WO2008050420A1

WO2008050420A1 - Motor

Info

Publication number: WO2008050420A1
Application number: PCT/JP2006/321278
Authority: WO
Inventors: Shigeru Endou; Shin Kumagai; Kazuo Nagatake; Licheng Dong; Atsushi Horikoshi; Toshimasa Wada
Original assignee: Nsk Ltd.
Priority date: 2006-10-25
Filing date: 2006-10-25
Publication date: 2008-05-02

Abstract

Provided is a motor for use in the atmosphere outside of the air, which is high in its performance and reliability while avoiding the atmosphere contamination, as might otherwise be caused by fixing magnetic poles. The motor is fixed by a magnetic force on the inner circumference of a rotor yoke (19a) made of a magnetic material and on outer rotor magnets (18), so that it is not easily displaced by the force of gravity or the torque at a power feeding time. In addition, the minimum clearance (C) in the circumferential direction between the confronting faces (18a and 18a) of the outer rotor magnets (18 and 18) is made smaller than the maximum width (W) of a spacer (19d) in the circumferential direction, and the portion to form the minimum clearance (C) in the circumferential direction between the confronting faces (18a and 18a) of the outer rotor magnets (18 and 18) is positioned radially outward of the portion of the maximum width (W) of the spacer (19d). Without using any adhesive, therefore, the drop or the circumferential displacement of the outer rotor magnets (18) can be suppressed even if an unexpected vibration or shock occurs. Even if the motor (D1) is arranged in vacuum, therefore, it is possible to avoid the atmosphere contamination which might otherwise be caused by the released gas (or the out gas) of occluded impurity molecules.

Description

Specification

motor

Technical field

[0001] The present invention relates to a motor suitable for use in an atmosphere outside the atmosphere, for example, in a vacuum.

Background art

[0002] For example, in a semiconductor manufacturing apparatus or the like, a workpiece is processed in an ultra-high vacuum atmosphere in a vacuum chamber in order to eliminate impurities as much as possible. As an actuator used in that case, for example, in a drive motor of a driven object positioning device, it is not possible to use a lubricant containing a volatile component such as general grease for a drive shaft bearing. Because it is impossible, the lubricity is improved by plating soft metals such as gold and silver on the inner and outer rings of the bearing. In addition, there is an actual situation when a stable material with excellent heat resistance and low emission gas is selected for the coil insulating material of the drive motor, the wiring coating material, and the adhesive of the laminated magnetic pole.

[0003] In particular, in recent years, the degree of integration of semiconductors has increased, and at the same time, higher density has been promoted by reducing the pattern width of ICs. In order to manufacture a wafer that can cope with this miniaturization, a high degree of uniformity in wafer quality is required. In order to meet this demand, it is important to further reduce the impurity gas concentration in the low-pressure gas processing chamber of the wafer. In addition, in order to perform microfabrication as required, a highly accurate positioning device is required. From this point of view, the following problems are pointed out when the above-mentioned conventional actuator is examined.

[0004] In other words, in the case of a drive motor used in a vacuum chamber equipped with an ultra-vacuum atmosphere, a stable material with excellent heat resistance and low emission gas is selected for the coil insulation of the drive motor and wiring coating, etc. However, as long as it is an organic insulating material, it is microscopically porous and has numerous holes on its surface. If this is exposed to the atmosphere, gas and water molecules will be taken in and occluded in the holes on the surface. It takes a long time for degassing to remove these occluded impure molecules by vacuum evacuation, and it is inevitable that the production efficiency will decline. [0005] Therefore, by using a circumferentially opposed surface magnet type brushless motor as the drive motor, the electrical wiring of the rotor is eliminated, and a cylindrical metal partition is provided between the stator and the rotor. On the other hand, many measures have been used to prevent the release of storage impurities by isolating the stator side, which uses many organic materials such as coil insulation and wiring coating, from the ultra-vacuum atmosphere.

On the other hand, although there is no electrical wiring in the rotor, it is common to use an adhesive to fix the permanent magnet and the rotor yoke, and in this ultra-vacuum atmosphere, the release of occluded impurity molecules from this adhesive is ignored. There is a problem that you can not. Here, the reason why the adhesive is widely used is that the stress due to the difference in linear expansion coefficient between the rotor yoke and the permanent magnet is absorbed by the adhesive layer, and the permanent magnet is cracked or chipped at extremely high or low temperatures. You can prevent it from being a good thing.

[0006] To solve such a problem, the rotor yoke is provided with two large-diameter portions having a diameter to which the thickness of the permanent magnet is added in the axial direction, and the permanent magnet is disposed between them to fill the curable resin. The permanent magnet is fixed, and a thin tube with a length sufficient to cover the two large-diameter portions is covered, and the mouth is welded and sealed to the two large-diameter portions, respectively. A motor having means for preventing the release of impurity molecules is described in Patent Document 1. Patent Document 1: JP 2000-69696 A By the way, the rotor yoke is a part that forms a magnetic path, but the change in magnetic flux is very small and eddy current loss hardly occurs. Therefore, low-carbon steel, which is a ferromagnetic material but is a structural material, is widely used. On the other hand, it is desirable to use a nonmagnetic metal such as austenitic stainless steel for the thin tube that covers the large diameter part of the rotor yoke together with the hardened resin that fixes the permanent magnet, in order to avoid short circuit of the magnetic flux. .

[0007] However, it is difficult to completely seal the two materials having greatly different material characteristics by welding, and an advanced technique is required, resulting in an increase in cost. In addition, if a curable resin is attached to the weld, it may cause poor welding. Furthermore, even if the thin tube is made of the same material as the rotor yoke, even if the thin tube uses the same material as the rotor yoke, the rotor yoke allows a certain amount of volume to pass through without saturating the magnetic flux. However, one thin tube narrows the air gap of the motor. Therefore, since the heat capacity that is desired to be very thin is very small, it is difficult to completely seal the tube by welding or cracking.

[0008] In addition, the ferromagnetic metal material used for the rotor yoke is very rusty, and it is necessary to carry out a fouling treatment such as nickel plating after welding in order to prevent dust generation in the vacuum chamber. There was a possibility that a pinhole was formed in the plating film applied to the welded part and the flaws proceeded from there immediately.

The present invention has been made in view of the problems of the prior art, and while avoiding atmospheric contamination caused by fixing of magnetic poles, the motor performance is high and the reliability is high in an atmosphere outside the atmosphere. It aims at providing the motor used.

Disclosure of the invention

[Invention 1]

The motor of the first aspect of the present invention is a motor having at least a main rotor and a stator, wherein the main rotor is an annular yoke having a magnetic force, and a plurality of magnetic poles made of permanent magnets arranged on the inner peripheral surface of the yoke. A spacer disposed between the adjacent magnetic poles and attached to the inner peripheral surface of the yoke,

The minimum distance in the circumferential direction between a pair of opposing surfaces of the adjacent magnetic poles is smaller than the maximum width in the circumferential direction of the spacer, and the minimum gap between the opposing surfaces of the magnetic poles is: It is characterized in that it is located radially outward from the maximum width portion of the spacer.

[0010] With this, the plurality of magnetic poles also having permanent magnet force are fixed to the inner peripheral surface by magnetic force with respect to the annular yoke having magnetic force, so that gravity is easily displaced by torque caused by energization. There is nothing. However, there is a risk that it may fall off or be displaced in the circumferential direction due to unexpected vibration or impact. Therefore, in the present invention, a spacer is disposed between adjacent magnetic poles, and the minimum circumferential interval between a pair of opposing surfaces of the adjacent magnetic poles is greater than the maximum circumferential width of the spacer. Since the portion that is small and has the smallest distance between the opposing surfaces of the magnetic poles is located radially outward from the portion having the maximum width of the spacer, unexpected vibration without using an adhesive or The magnetic poles can be prevented from falling off or displaced in the circumferential direction due to impact, etc. It is possible to avoid atmospheric pollution caused by outgas. However, the motor of the present invention is not limited to use in a vacuum. In some cases, such as heat-resistant applications, it may be undesirable to use an adhesive. Here, “radial direction” and “axial direction” are based on the yoke.

(Invention 2)

The motor of the invention 2 is characterized in that, in the motor of the invention 1, a gap is formed between the facing surface of the magnetic pole and the spacer.

[0011] With this, if a gap is formed between the opposing surface of the magnetic pole and the spacer, the difference in thermal expansion between the yoke and the magnetic pole due to temperature change is absorbed, and cracks and chips are lost. You can avoid problems such as.

(Invention 3)

The motor of the invention 3 is the motor of the invention 1 or 2, characterized in that the yoke has a contact portion that contacts the magnetic pole when the magnetic pole is displaced in the axial direction.

[0012] Thereby, when the magnetic pole has a contact portion that comes into contact with the magnetic pole when the magnetic pole is displaced in the axial direction, the yoke can prevent the magnetic pole from being displaced in the axial direction. it can.

(Invention 4)

The motor of the invention 4 is the direct drive motor of the invention 1 or 2, characterized in that the spacer has a contact portion that contacts the magnetic pole when the magnetic pole is displaced in the axial direction. To do.

Accordingly, when the spacer has a contact portion that contacts the magnetic pole when the magnetic pole is displaced in the axial direction, the spacer prevents the magnetic pole from being displaced in the axial direction. be able to.

(Invention 5)

The motor according to a fifth aspect of the present invention is the motor according to any one of the first to fourth aspects, wherein the spacer is fixed to the yoke by a bolt that also has a non-magnetic force.

[0014] Thereby, the spacer is fixed to the yoke by a bolt having a nonmagnetic force. If it is fixed, the motor performance can be secured while the spacer is securely fixed.

(Invention 6)

The motor of the invention 6 is the motor according to any one of the inventions 1 to 5, wherein the motor is a direct drive motor that directly drives the rotor without using a speed reducer or the like, and is used in an atmosphere outside the atmosphere. And a partition that extends the housing force and separates the atmosphere side from the atmosphere outside,

The main rotor is disposed outside the atmosphere with respect to the partition wall, and the stator is disposed on the atmosphere side with respect to the partition wall,

Furthermore, it has an auxiliary port that is disposed on the atmosphere side with respect to the partition wall and rotates with the main rotor, and a detector that detects the rotation speed of the auxiliary rotor.

[0015] Thereby, by placing the detector on the atmosphere side from the partition wall, it is possible to prevent the impure molecules in the wiring coating from contaminating the atmosphere outside the atmosphere from the partition wall, and By simultaneously driving the main rotor and the sub-rotor, the rotation angle of the sub-rotor is detected by the detector, so that the rotation angle of the main rotor can be obtained with high accuracy.

(Invention 7)

The direct drive motor of the invention 7 is a direct drive motor used in an atmosphere outside the atmosphere.

Knowing and

A partition wall extending the housing force and isolating the atmosphere side and the atmosphere outside;

An outer rotor disposed outside the atmosphere with respect to the partition;

A stator and an inner rotor disposed on the atmosphere side with respect to the partition;

A detector for detecting the rotational speed of the inner rotor,

The stator is characterized in that the outer rotor and the inner rotor are driven simultaneously.

[0016] Accordingly, in a direct drive motor used in an atmosphere outside the atmosphere, the housing, the partition that extends the housing force and isolates the atmosphere side from the outside of the atmosphere, An outer rotor disposed outside the atmosphere with respect to the partition wall, a stator and an inner rotor disposed on the atmosphere side with respect to the partition wall, and a detector that detects a rotational speed of the inner rotor, Since the outer rotor and the inner rotor are driven at the same time, by placing the detector on the air side from the partition wall, the occluded impurity molecules of the wiring coating may contaminate the atmosphere outside the air from the partition wall. The stator detects the rotation angle of the inner rotor with the detector by simultaneously driving the outer rotor and the inner rotor, so that the rotation angle of the outer rotor can be accurately obtained. Togashi.

(Invention 8)

The direct drive motor of invention 8 is the direct drive motor of invention 7, characterized in that the outer rotor and the inner rotor have the same number of magnetic poles.

[0017] With this, when the outer rotor and the inner rotor have the same number of magnetic poles, the rotation angles of the outer rotor and the inner rotor become equal, so the rotation angle of the inner rotor is detected. Thus, the rotation angle of the outer rotor can be obtained immediately. However, the present invention is not limited to this. For example, the number of magnetic poles in the outer rotor and the number of magnetic poles in the inner rotor may be a multiple or a fraction of an integer.

(Invention 9)

The direct drive motor according to a ninth aspect is characterized in that in the direct drive motor according to the seventh or eighth aspect, an inner rotor is disposed radially inward of the stator.

[0018] Thus, when the inner rotor is arranged on the inner side in the radial direction of the stator, the stator can be driven reliably, but it may be arranged so as to be shifted in the axial direction.

(Invention 10)

The direct drive motor of the invention 10 is a direct drive motor used in an atmosphere outside the atmosphere.

Knowing and

An outer rotor disposed outside the atmosphere with respect to the partition wall, and a magnetic coupling rotor that rotates integrally with the outer rotor; A stator that is arranged on the atmosphere side with respect to the partition and drives the outer rotor; an inner rotor that is arranged on the atmosphere side with respect to the partition;

A detector for detecting the rotational speed of the inner rotor,

The magnetic coupling rotor and the inner rotor rotate in synchronization by a magnetic coupling action.

Accordingly, in the direct drive motor used in an atmosphere outside the atmosphere, the housing, the partition extending the housing force and isolating the atmosphere side from the outside of the atmosphere, and the outside of the atmosphere with respect to the partition An outer rotor disposed therein and a magnetic coupling rotor that rotates integrally with the outer rotor; a stator that is disposed on the atmosphere side with respect to the partition; and that drives the outer port; and an atmosphere side with respect to the partition An inner rotor disposed on the inner rotor, and a detector that detects the rotational speed of the inner rotor, and the magnetic coupling rotor and the inner rotor rotate in synchronization by a magnetic coupling action. By placing the detector on the air side of the partition wall, it is possible to prevent the impurities stored in the wiring cover from contaminating the atmosphere outside the air from the partition wall, By detecting the rotation angle of the inner rotor that rotates in synchronization with the magnetic coupling rotor by the coupling action, the rotation angle of the outer rotor can be obtained with high accuracy. In the present invention, a force in which the “outer rotor” and the “magnetic coupling rotor” are different members in form, for example, when a driving magnet and a magnetic coupling magnet are provided on a single rotor, It can be said that the partial force of the rotor provided with the driving magnet ^ outer rotor "and the portion of the rotor provided with the magnet for magnetic force coupling is the" magnetic coupling rotor ". included.

(Invention 11)

The direct drive motor according to an eleventh aspect of the invention is characterized in that, unlike the direct drive motor according to the tenth aspect, the peak value of the resonance frequency gain in the magnetic coupling system is suppressed by the partition.

[0020] Accordingly, the partition between the atmosphere-side rotor and the atmosphere-side rotor makes it possible to perform positioning with less vibration due to the effect of suppressing the peak value of the resonance frequency gain in the magnetic coupling system. (Invention 12)

The direct drive motor of the invention 12 is a direct drive motor used in an atmosphere outside the atmosphere.

Knowing and

A partition wall extending the housing force and isolating the atmosphere side from the atmosphere outside;

An outer rotor disposed outside the atmosphere with respect to the partition;

A stator disposed on the atmosphere side with respect to the partition; an inner rotor disposed on the atmosphere side with respect to the partition;

A detector for detecting the rotational position of the inner rotor,

The partition has an attachment portion attached to the housing, the outer rotor, a cylindrical portion extending between the stator and the inner rotor, and a bottom portion, and the bottom portion is attached to the housing. On the other hand, it is restricted in the axial direction. Thus, in the direct drive motor used in an atmosphere outside the atmosphere, the housing, the partition extending the housing force, separating the atmosphere side from the outside of the atmosphere, and disposed outside the atmosphere with respect to the partition wall An outer rotor, a stator and an inner rotor arranged on the atmosphere side with respect to the partition wall, and a detector for detecting a rotational position of the inner rotor, the stator driving the outer rotor, Since the inner rotor is rotated together with the outer rotor, by placing the detector inside the partition wall, it is possible to prevent the impurities stored in the wiring cover from contaminating the atmosphere outside the partition wall. In addition, the partition wall includes an attachment portion attached to the housing, the outer rotor, a cylindrical portion extending between the stator and the inner rotor, and a bottom portion, and the bottom portion is Since the housing is not restrained in the axial direction, the bottom portion is pressed against the housing even when a dimensional error or deformation occurs in the partition wall due to dimensional accuracy, mechanical accuracy, or temperature change. Since it is not pulled or pulled, the axial stress and bending stress of the partition wall can be relaxed, thereby preventing seal failure and breakage. Further, since it is not necessary to process the mounting portion of the partition wall and the housing to which the partition wall is mounted with high accuracy, a lower cost direct drive motor can be provided. (Invention 13)

The direct drive motor of the invention 13 is a direct drive motor used in an atmosphere outside the atmosphere.

Knowing and

An outer rotor disposed outside the atmosphere with respect to the partition;

A detector for detecting the rotational position of the inner rotor,

The partition wall connects the mounting portion attached to the housing, the outer rotor, a cylindrical portion extending between the stator and the inner rotor, and the mounting portion and the cylindrical portion. And a thickness of the connecting portion is thinner than a thickness of the mounting portion.

[0022] Thus, in contrast to the effect of the twelfth aspect, the partition wall includes an attachment portion attached to the housing, the outer rotor, and a cylindrical portion extending between the stator and the inner rotor. The attachment portion and the tubular portion are connected to each other, and the thickness of the attachment portion is thicker than the thickness of the connection portion, and therefore, due to dimensional accuracy, mechanical accuracy, and temperature change. Even when the partition wall is deformed, the thin connecting portion is deformed first, so that axial stress and bending stress of the partition wall can be relieved, thereby preventing a seal failure or breakage. Can do. Accordingly, since it is not necessary to process the mounting portion of the partition wall and the housing to which the partition wall is mounted with high accuracy, a lower cost direct drive motor can be provided.

(Invention 14)

The direct drive motor according to a fourteenth aspect of the invention is characterized in that the connecting portion has a wave shape compared to the direct drive motor of the thirteenth aspect.

[0023] Thereby, if the connecting portion is wavy, stress relaxation can be achieved more effectively by the force applied portion.

(Invention 15) A motor system according to a fifteenth aspect of the present invention is a motor system in which a plurality of direct drive motors used in an atmosphere outside the atmosphere are coaxially coupled.

Each direct drive motor

Knowing and

An outer rotor disposed outside the atmosphere with respect to the partition;

A detector for detecting the rotational position of the inner rotor,

The outer rotor force of at least one direct drive motor is supported by a bearing with respect to the outer rotor of another direct drive motor. As a result, in a motor system in which a plurality of direct drive motors used in an atmosphere outside the atmosphere are coaxially coupled, each direct drive motor force, udging, and the housing force are extended to isolate the atmosphere side from the atmosphere outside. A partition wall that is disposed outside the atmosphere with respect to the partition wall, a stator and an inner rotor that are disposed on the atmosphere side with respect to the partition wall, and a detector that detects a rotational position of the inner rotor. The stator drives the outer rotor, and the inner rotor is rotated together with the outer rotor. Therefore, by placing the detector inside the partition wall, the occluded impurity molecules of the wiring cover are Contamination of the atmosphere outside the partition is prevented. Also, the outer rotor force of at least one direct drive motor is supported by a bearing with respect to the outer rotor of another direct drive motor, so that the outer rotors of a plurality of direct drive motors are coaxial with each other. When the frog redder arm is driven, the operation accuracy can be increased. Then, if the outer rotor of the one direct drive motor is removed, the bearing supporting the powerful outer rotor can be exposed, and the inspection and removal thereof can be easily performed, so that the maintainability is improved. Furthermore, since only the outer rotor outside the partition wall is removed, there is no need to remove the entire direct drive motor, so that a leak check or the like is not required at the time of reassembly, and the assemblability is improved. (Invention 16)

The motor system of the invention 16 is the motor system of the invention 15 characterized in that the partition wall force of one direct drive motor is common to the partition walls of other direct drive motors.

[0025] Thus, it is preferable that the partition wall force of one direct drive motor is the same as that of the partition wall of another direct drive motor, because the number of parts and the seal location can be reduced.

(Invention 17)

A motor system according to a seventeenth aspect of the present invention is the motor system according to the sixteenth aspect of the present invention, wherein the partition wall has a cup shape.

[0026] Accordingly, it is preferable that the partition wall be cup-shaped because the number of parts is reduced and the number of seals is reduced. However, the partition wall is not limited to a cup shape, and it may be combined with a cylinder and a disk and welded together, or a combination of a truncated cone and a disk whose diameter is reduced in the direction of removing the outer rotor. Also good.

(Invention 18)

The motor system of the invention 18 is a motor system in which a plurality of direct drive motors used in an atmosphere outside the atmosphere are coaxially coupled.

Each direct drive motor

Knowing and

An outer rotor disposed outside the atmosphere with respect to the partition;

A detector for detecting the rotational position of the inner rotor,

The outer rotor force of one direct drive motor is supported by a bearing against one of the ends of the housing, and the outer rotor of the other direct drive motor is connected to the other end of the housing. Is supported by a bearing. [0027] Thus, in the motor system in which a plurality of direct drive motors used in an atmosphere outside the atmosphere are coaxially coupled, each direct drive motor force, udging, and the housing force extend, and the atmosphere side and the atmosphere A partition that isolates the outside, an outer rotor that is disposed outside the atmosphere with respect to the partition, a stator and an inner rotor that are disposed on the atmosphere side with respect to the partition, and a detection that detects the rotational position of the inner rotor And the stator drives the outer rotor and the inner rotor is rotated together with the outer rotor. Therefore, by placing the detector inside the partition wall, the wiring cover has an impure impurity. Molecules are prevented from contaminating the atmosphere outside the partition. Also, since the outer rotor of the direct drive motor is supported by bearings at both ends of the housing, the mechanical accuracy of each other is hardly affected. Therefore, it is possible to provide a motor system with a large load capacity and allowable moment V.

(Invention 19)

The motor system of the nineteenth aspect of the present invention is the motor system of the eighteenth aspect of the present invention, wherein the shape of one end of the V of the housing is made detachable in the axial direction of the outer rotor of all direct drive motors. It is characterized by that.

[0028] With this, when one end shape of the housing supporting the partition wall structure is configured such that the outer rotor of the direct drive motor can be removed in the axial direction, The rotor can also remove the bulkhead force, which can be easily inspected and removed, improving maintainability. Furthermore, since it is only necessary to remove the outer rotor outside the partition wall, it is not necessary to remove the entire direct drive motor, so that a leak check or the like is not required at the time of reassembly, and assemblability is improved.

(Invention 20)

The motor system of the invention 20 is the motor system of the invention 18 characterized in that the partition wall force of one direct live motor is common to the partition walls of other direct drive motors.

[0029] Thus, it is preferable that the partition wall force of one direct live motor is the same as that of the partition wall of another direct drive motor, because the number of parts and the seal location can be reduced. (Invention 21)

The motor system according to a twenty-first aspect is the motor system according to the eighteenth aspect, characterized in that the partition wall has a sealing mechanism with the housing at both ends.

[0030] With this configuration, if the partition wall has sealing mechanisms (O-rings or the like) with the housing at both ends, the both ends of the housing can be disposed outside the atmosphere, so that the direct drive motor The outer rotor can be supported by bearings on both ends of the housing. (Invention 22)

The motor system of the invention 22 is a motor system in which four or more direct drive motors used in an atmosphere outside the atmosphere are coaxially coupled.

Each direct drive motor

Knowing and

An outer rotor disposed outside the atmosphere with respect to the partition;

A detector for detecting the rotational position of the inner rotor,

The outer rotor force of one direct drive motor is supported by a bearing against one of the ends of the housing, and the outer rotor of the other direct drive motor is connected to the other end of the housing. The outer rotor force of at least one direct drive motor is supported by a bearing with respect to each of the outer rotors of the two direct drive motors.

[0031] Thus, in a motor system in which four or more direct drive motors used in an atmosphere outside the atmosphere are coaxially coupled, each direct drive motor force housing extends from the housing and is connected to the atmosphere side. A partition that isolates the outside of the atmosphere, an outer rotor that is disposed outside the atmosphere with respect to the partition, a stator and an inner rotor that are disposed on the atmosphere side with respect to the partition, and a detection that detects a rotational position of the inner rotor The stator drives the outer rotor, and the inner rotor together with the outer rotor Therefore, by placing the detector inside the partition, it is possible to prevent the impurities stored in the wiring cover from contaminating the atmosphere outside the partition. The outer rotor of the direct drive motor is supported by bearings on both ends of the housing, and the outer rotor of each direct drive motor is connected to the outer side of another direct drive motor. Since the rotor is supported by the bearing, the same outer rotor connected by the bearing has a high degree of coaxiality with each other, and the outer rotor connected by the bearing is installed at the other housing end. It is possible to provide a motor system with small mutual interference of mechanical accuracy. Therefore, when applied to a 2-axis coaxial frog redder arm robot, it is possible to improve the operation accuracy and increase the load.

(Invention 23)

The motor system according to a twenty-third aspect of the present invention is the motor system according to the twenty-second aspect of the invention, wherein the shape of one end of the housing V is shifted so that the outer rotors of all the direct drive motors can be removed in the axial direction. It is characterized by being beaten!

[0032] Thereby, one end shape of the housing supporting the partition wall structure is made detachable in the axial direction of the outer rotor of the direct drive motor. Since the outer rotor of the motor can also be removed, it can be easily inspected and removed, thus improving maintainability. Furthermore, it is only necessary to remove the outer rotor on the outside of the partition wall, so there is no need to remove the entire direct drive motor, so there is no need to check for leaks, etc., improving assembly.

(Invention 24)

A motor system according to a twenty-fourth aspect of the present invention is the motor system according to the twenty-second aspect, wherein the housing can be divided into units commonly used in two adjacent direct drive motors.

[0033] Thus, if the housing can be divided into units commonly used in two adjacent direct drive motors, the housing is excellent in assemblability and adjustments such as phase alignment between the motor and the detector are possible. Easy to do, so preferred.

(Invention 25) A motor system according to a twenty-fifth aspect of the present invention is the motor system according to the twenty-second aspect, characterized in that the partition wall force of one direct live motor is common to the partition walls of another direct drive motor.

[0034] Accordingly, it is preferable that the partition wall force of one direct drive motor is the same as that of the partition wall of another direct drive motor because the number of parts and seal locations can be reduced.

(Invention 26)

A motor system according to a twenty-sixth aspect of the present invention is the motor system according to the twenty-second aspect of the present invention, characterized in that both ends of the partition wall have a sealing mechanism with the housing.

[0035] Thus, if the partition wall has a sealing mechanism (O-ring or the like) with the housing at both ends, the both ends of the housing can be disposed outside the atmosphere, so the direct drive motor The outer rotor can be supported by bearings at both ends of the housing. (Invention 27)

The motor system of the invention 27 is a motor system in which a first direct drive motor and a second direct drive motor used in an atmosphere outside the atmosphere are coaxially coupled.

Each direct drive motor

Knowing and

An outer rotor disposed outside the atmosphere with respect to the partition;

A detector for detecting the rotational position of the inner rotor,

Further, the outer rotor of the second direct drive motor adjacent to the outer rotor of the first direct drive motor is supported via a second bearing,

The outer rotor of the first direct drive motor is supported via a first bearing by a bearing holder removably attached to the housing. It is characterized by that.

Thus, in the motor system in which the first direct drive motor and the second direct drive motor used in an atmosphere outside the atmosphere are coaxially coupled, each direct drive motor includes a housing and the housing cover. A partition wall that separates the atmosphere side from the atmosphere outside, an outer rotor disposed outside the atmosphere with respect to the partition wall, a stator disposed on the atmosphere side with respect to the partition wall, and the atmosphere with respect to the partition wall And an inner rotor that rotates with the outer rotor, and a detector that detects the rotational position of the inner rotor.By placing the detector on the atmosphere side of the partition wall, It is possible to prevent the impure molecules of the wiring coating from contaminating the atmosphere outside the atmosphere of the partition wall. Further, the outer rotor of the second direct drive motor adjacent to the outer rotor of the first direct drive motor is supported via a second bearing, and the first rotor is supported by the first rotor. Since the outer rotor of the direct drive motor is supported via a first bearing by a bearing holder that is detachably attached to the housing, the first rotor can be removed by removing the bearing holder. The direct drive motor can be separated from the housing force, and maintenance work including inspection of the bearing attached to the bearing holder can be saved.

(Invention 28)

A motor system according to a twenty-eighth aspect is the motor system according to the twenty-seventh aspect, wherein the bearing holder is fixed to the housing by a bolt, and the bolt is disposed outside the outer rotor of the first direct drive motor. It is characterized by.

[0037] Thereby, the bearing holder is fixed to the housing by a bolt, and when the bolt is arranged outside the outer rotor of the first direct drive motor, the outer rotor to be applied is This is preferable because the bolt can be loosened without being removed. Note that “arranged outside the outer rotor” means that the bolt or the tool and the outer rotor do not interfere with each other at least when the bolt is detached. Therefore, when the outer diameter of the outer rotor is non-circular, depending on the rotational phase of the outer rotor, even if the bolt is inside the outer periphery, the bolt is rotated by rotating the outer rotor. When going outside, the bolt is placed outside the outer rotor Let's do it.

(Invention 29)

The motor system of the invention 29 is the motor system of the invention 27 to 28, wherein the minimum inner diameter of the outer rotor of the first direct drive motor and the outer rotor of the second direct drive motor is the maximum outer diameter of the partition wall. It ’s getting bigger,

When the bearing holder is removed from the housing, the outer ring rotor of the first direct drive motor and the outer ring rotor of the second direct drive motor can be pulled out along the partition wall in the axial direction. It is characterized by becoming.

[0038] Thereby, the minimum inner diameter of the outer rotor of the first direct drive motor and the outer rotor of the second direct drive motor is larger than the maximum outer diameter of the partition wall, When the bearing holder is removed from the housing, the outer ring rotor of the first direct drive motor and the outer ring rotor of the second direct drive motor are integrally extracted along the partition in the axial direction. If possible, it is preferable because both outer rotors can be disassembled integrally during maintenance.

(Invention 30)

A motor system according to a thirty-third aspect of the invention is the motor system according to the twenty-ninth aspect, wherein a bolt for fixing the first bearing and the bearing holder is exposed when the bearing force is removed from the housing force.

[0039] Thus, when the bolt for fixing the first bearing and the bearing holder is exposed when the bearing holder is removed from the housing, the forceful bolt can be loosened, and thus the first This is preferable because the outer rotor of the direct drive motor can be easily disassembled. Here, “exposed” means that a space is created in which a tool can be engaged and a bolt can be loosened.

(Invention 31)

A motor system according to a thirty-first aspect is the motor system according to the twenty-seventh aspect, wherein the outer rotor of the second direct drive motor is formed by connecting a plurality of parts with bolts, and the outer rotor is in a state where the motor system is assembled. By loosening the bolts that connect multiple parts, you can remove some of the parts. In this state, the bolt that fixes the second bearing and the outer ring rotor of the first direct drive motor is exposed.

Accordingly, the outer rotor of the second direct drive motor is formed by connecting a plurality of parts (for example, a second outer rotor 21b ′ and a cylindrical member 23 ′ described later) with bolts, and the motor system is In the assembled state, by loosening the bolt that connects the plurality of parts of the outer rotor, it is possible to remove some of the parts (for example, the cylindrical member 23 '), and remove the part of the parts. In this state, when the bolt for fixing the second bearing and the outer ring rotor of the first direct drive motor is exposed, the powerful bolt can be loosened. Therefore, the outer rotor of the second direct drive motor can be This is preferable because it can be easily disassembled!

(Invention 32)

A motor system according to a thirty-second aspect of the present invention is the motor system according to the thirty-first aspect of the present invention, in which the bolt that fixes the second bearing and the outer ring rotor of the first direct drive motor is loosened, thereby The remaining parts of the outer rotor can be pulled out in the axial direction along the partition wall.

[0041] Thus, by loosening a bolt that fixes the second bearing and the outer ring rotor of the first direct drive motor, the remaining components (for example, the outer rotor of the second direct drive motor (for example, If the second outer rotor 21b ′) can be pulled out along the partition wall in the axial direction, it is preferable because the outer rotor of the second direct drive motor can be easily disassembled.

(Invention 33)

The motor system according to a thirty-third aspect is the motor system according to any one of the twenty-seventh to thirty-second aspects, wherein the partition wall and the housing are common to each direct drive motor.

[0042] Thus, in each direct drive motor, it is preferable that the partition and the housing are common, because the number of parts can be reduced and the number of seal members for sealing between the members can be reduced.

(Invention 34) The motor system of the invention 34 is a motor system in which a plurality of direct drive motors used in an atmosphere outside the atmosphere are coaxially coupled.

Each direct drive motor

Knowing and

An outer rotor disposed outside the atmosphere with respect to the partition;

A detector for detecting the rotational position of the inner rotor,

Further, the outer rotors and inner rotors of adjacent direct drive motors

And a magnetic shield is disposed between at least one of the stators.

As a result, in a direct drive motor used in an atmosphere outside the atmosphere, the housing, the housing force extends, the partition that separates the atmosphere side and the outside of the atmosphere, and the outside of the partition wall are arranged outside the atmosphere. An outer rotor, a stator and an inner rotor arranged on the atmosphere side with respect to the partition wall, and a detector for detecting a rotational position of the inner rotor, the stator driving the outer rotor, Since the inner rotor is rotated together with the outer rotor, by placing the detector inside the partition wall, it is possible to prevent the impurities stored in the wiring cover from contaminating the atmosphere outside the partition wall. In addition, since the magnetic shield is arranged between at least one of the outer rotors, the inner rotors, and the stators in the adjacent direct drive motor, the rotor is affected by leakage magnetic flux generated by the stator force and electromagnetic noise. In addition, the direct motor adjacent to the rotor can be prevented from reaching the stator. Therefore, the motor system can be made thin.

(Invention 35)

The motor system of the invention 35 is a motor system in which a plurality of direct drive motors used in an atmosphere outside the atmosphere are coaxially coupled.

Each direct drive motor Knowing and

An outer rotor disposed outside the atmosphere with respect to the partition;

A detector for detecting the rotational position of the inner rotor,

Further, the outer rotors and inner rotors of adjacent direct drive motors

And at least one of the stators has a different number of magnetic poles.

As a result, in a direct drive motor used in an atmosphere outside the atmosphere, the housing, the housing force extends, the partition that separates the atmosphere side and the outside of the atmosphere, and the outside of the partition wall are arranged outside the atmosphere. An outer rotor, a stator and an inner rotor arranged on the atmosphere side with respect to the partition wall, and a detector for detecting a rotational position of the inner rotor, the stator driving the outer rotor, Since the inner rotor is rotated together with the outer rotor, by placing the detector inside the partition wall, it is possible to prevent the impurities stored in the wiring cover from contaminating the atmosphere outside the partition wall. In addition, since the number of magnetic poles is different between at least one of the outer rotors, the inner rotors, and the stators in adjacent direct drive motors, leakage magnetic flux, electromagnetic noise, etc. generated from the rotor and stator However, it is possible to suppress the problem that the rotor in the direct motor adjacent to it drives the stator. Therefore, the motor system can be made thin.

(Invention 36)

A motor system according to a thirty-sixth aspect of the present invention is a motor system in which a plurality of direct drive motors used in an atmosphere outside the atmosphere are coaxially coupled.

Each direct drive motor

Knowing and

An outer rotor disposed outside the atmosphere with respect to the partition; A stator disposed on the atmosphere side with respect to the partition; an inner rotor disposed on the atmosphere side with respect to the partition;

A detector for detecting the rotational position of the inner rotor,

Furthermore, a rotating wheel of a bearing device that rotatably supports the outer rotor is fitted into a rotor yoke.

[0045] Accordingly, in the direct drive motor used in an atmosphere outside the atmosphere, the housing, the partition that extends the housing force and separates the atmosphere side from the outside of the atmosphere, and the outside of the atmosphere with respect to the partition wall. An outer rotor disposed; a stator and an inner rotor disposed on the atmosphere side with respect to the partition; and a detector that detects a rotational position of the inner rotor, wherein the stator drives the outer rotor. Since the inner rotor is rotated together with the outer rotor, by placing the detector inside the partition wall, it is possible to prevent the impurity molecules stored in the wiring cover from contaminating the atmosphere outside the partition wall. Rotational accuracy is achieved by fitting the rotating wheel of the bearing device that is rotatably supported with the outer rotor to a rotor yoke that is easy to obtain processing accuracy and has a linear expansion coefficient substantially the same as the driving wheel of the bearing device. And improvement of friction torque due to temperature change can be prevented.

Brief Description of Drawings

FIG. 1 is a perspective view of a frog redder arm type transfer device using a motor that is powerful in the present embodiment.

FIG. 2 is a view of the configuration of FIG. 1 cut along the Π-Π line and viewed in the direction of the arrow.

[Fig. 3] Fig. 3 is a view of the configuration of Fig. 2 cut along the ΠΙ-ΠΙ line and viewed in the direction of the arrow.

FIG. 4 is an enlarged view showing an arrow IV part of FIG.

FIG. 5 is a view of the configuration of FIG. 4 taken along the line V-V and viewed in the direction of the arrow.

FIG. 6 is a diagram illustrating an example of a resolver control circuit.

FIG. 7 is a diagram showing an example of a motor control circuit.

FIG. 8 is a perspective view of a frog redder arm type transport device using a direct drive motor that works according to the present embodiment.

FIG. 9 is a view of the configuration of FIG. 8 cut along the Π- で line and viewed in the direction of the arrow.

FIG. 10 is a view of the configuration of FIG. FIG. 11 is a diagram illustrating an example of a resolver control circuit.

FIG. 12 is a diagram showing an example of a motor control circuit.

[13] FIG. 13 is a diagram showing a modification of the present embodiment.

14 is a cross-sectional view similar to FIG. 9 of a direct drive motor that can be used in the transport device shown in FIG.

[15] FIG. 15 is a schematic diagram showing a state where eddy current loss occurs in the partition wall 113.

FIG. 16 is a schematic view similar to FIG. 15 showing three magnets arranged in a line.

FIG. 17 is a block diagram of a motor control system when there is no partition wall.

FIG. 18 is a block diagram of a motor control system when there is a partition wall.

FIG. 19 is a diagram showing frequency characteristics of a transfer function G.

FIG. 20 is a diagram showing frequency characteristics of a transfer function G.

FIG. 21 is a view showing the spring stiffness of the magnetic coupling.

FIG. 22 is a perspective view of a frog redder arm type transport device using a direct drive motor that works according to the present embodiment.

FIG. 23 is a view of the configuration of FIG. 22 cut along the Π-Π line and viewed in the direction of the arrow.

FIG. 24 is a diagram showing an example of a resolver control circuit.

FIG. 25 is a diagram showing an example of a motor control circuit.

FIG. 26 is a cross-sectional view showing a second embodiment.

圆 27] It is a cross-sectional view showing a third embodiment.

圆 28] It is a sectional view showing a fourth embodiment.

FIG. 29 is a perspective view of a frog redder arm type conveyance device using a motor system including a direct drive motor that is effective in the present embodiment.

FIG. 30 is a view of the configuration of FIG. 29 taken along the line Π-Π and viewed in the direction of the arrow.

FIG. 31 is a diagram illustrating an example of a resolver control circuit.

FIG. 32 is a diagram showing an example of a motor control circuit.

圆 33] A cross-sectional view showing a second embodiment.

FIG. 34 is a perspective view of a frog redder arm type transfer device using a direct drive motor that is effective in the present embodiment. FIG. 35 is a view of the configuration of FIG. 34 taken along the line II-II and viewed in the direction of the arrow.

FIG. 36 is a diagram illustrating an example of a resolver control circuit.

FIG. 37 is a diagram showing an example of a motor control circuit.

FIG. 38 is a perspective view of a frog redder arm type conveyance device using a direct drive motor that works according to the present embodiment.

FIG. 39 is a view of the configuration of FIG. 38 taken along the line Π-Π and viewed in the direction of the arrow.

FIG. 40 is a diagram illustrating an example of a resolver control circuit.

FIG. 41 is a diagram showing an example of a motor control circuit.

FIG. 42 is a cross-sectional view showing an exploded process of the motor system according to the present embodiment.

FIG. 43 is a cross-sectional view showing an exploded process of the motor system according to the present embodiment.

FIG. 44 is a cross-sectional view showing an exploded process of the motor system according to the present embodiment.

FIG. 45 is a cross-sectional view showing an exploded process of the motor system according to the present embodiment.

FIG. 46 is a perspective view showing a disassembly process of the motor system according to the present embodiment.

FIG. 47 is a perspective view showing an exploded process of the motor system according to the present embodiment.

FIG. 48 is a perspective view showing a disassembly process of the motor system according to the present embodiment.

FIG. 49 is a perspective view showing an exploded process of the motor system according to the present embodiment. FIG. 50 is a cross-sectional view showing a modification of the present embodiment.

FIG. 51 is a perspective view of a frog redder arm type transport device using a direct drive motor that is powerful in a modified example.

FIG. 52 is a perspective view of a frog redder arm type conveyance device using a direct drive motor that works according to the present embodiment.

FIG. 53 is a view of the configuration of FIG. 52 taken along the Π-Π line and viewed in the direction of the arrow.

FIG. 54 is a diagram showing an example of a resolver control circuit.

FIG. 55 is a diagram showing an example of a motor control circuit.

圆 56] A sectional view showing a modification of the present embodiment.

Explanation of symbols

10 Body

10 disc Body

1 Lid member

1 Inner rotor magnet for magnetic coupling 2 Magnetic shield plate

3 Magnetic shield plate

7 Bearing holder

8 Coupling outer rotor magnet 9 Knock yoke

a Flange

Small disk

Bonoleto

, 111 Vol

0 Disc member

0 Upper disc

0 Body

0a Flange

0b Cylindrical mounting part

1 small disk

2 Large disc

3 Bulkhead

3a Bulkhead Honoreda

3b Thin cylinder

4-point contact ball bearing

5 Inner holder

Outer rotor

Outer holder

Outer rotor magnet

Knock yoke Large disc

Bulkhead

Body

112 body

1 Inner rotor

3 Bearing

5 Back yoke

5 Magnetic shield plate 6 Detection rotor

7 Incremental resolver 8 Absolute resolver 9 Stator

a Flange

a, 112a Flange 咅 b Outer peripheral edge

d hole

e missing

Bulkhead

, 113 Bulkhead

113, 213, 313 Bulkhead 0 Magnetic shield plate a Disk part

b Cylindrical part

4-point contact ball bearing Inner ring holder

Honoreda

Outer rotor

bolt Outer holder

107 Bearing holder

, 17, bearing holder

Outer rotor magnet

, 18, Bonore 卜

a Opposing surface

/ Cook York

19 '4 point contact ball bearing

19 ', 119, 119' 4 point contact ball bearing a Rotor yoke

b Yoke holder

c Bol

d Spacer

e Vol

f Screw hole

g side

h Short flange

Stator holder

, 20 'Vol

Inner rotor

The 21 'outer rotor

, 21, Outer rotor member

, 21 ', 121, 121' Outer rotor member a, 21a 'Permanent magnet

b, 21b 'York

Resolver holder

, 22 'Vol

Ball bearing Cylindrical member

123 Cylindrical member

'' Ring-shaped member

', 123, ring-shaped member

Inner rotor magnet

, 24 'Vol

Knock York

, 25 'Magnetic shield plate

Detection rotor Absolute:

Stator

29 'stator

29 ', 129, 129' stator Magnetic shield plate

, 30, inner rotor

30 ', 130, 130' Inner rotor a, 30a 'Permanent magnet

b, 30b 'knock yoke

32, Resolver Honoreda

, 32 ', 132, 132' resorno holder, 33 'bearing

, 33 ', 133, 133' bearing, 34 'detection rotor

34, 134, 134 'Detection rotor a, 34a'

a, 34a \ 134a, 134a'b, 34b, Absolute Resol Paro 34b, 34b \ 134b, 134b 'Absolute resolver rotor

35, 35 ', 135, 135' Incremental resolver stator

36, 36, absolute resolver stator

36, 36 ', 136, 136' Absolute resolver stator

41 Magnetic shield plate

A1, A2 arm

Al, A2, Al, A2, Arm

D1, D2 motor

D1, D2 Direct drive motor

Dl, D2, D3, D4 direct drive motor

DMC1 motor control circuit

DMC2 motor control circuit

G Surface plate

L1, L2 link

LI, L2, Ll \ L2 'link

OR O—Ring

T table

T ゝ T 'table

BEST MODE FOR CARRYING OUT THE INVENTION

[First embodiment]

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view of a frog redder arm type transfer device using a motor that works in this embodiment. In Fig. 1, two motors Dl and D2 are connected in series. The first arm A1 is connected to the rotor of the lower motor D1, and the first link L1 is pivotally connected to the tip of the first arm A1.

On the other hand, the second arm A2 is coupled to the rotor of the upper motor D2, and the second link L2 is pivotably coupled to the leading end of the second arm A2. Links LI and L2 place wafer W Each table is pivotably connected to the table T! Speak.

[0049] The force apparent from Fig. 1 If the rotors of the motors Dl and D2 rotate in the same direction, the table T also rotates in the same direction. If the powerful rotor rotates in the opposite direction, the table T becomes a motor It approaches or separates from Dl and D2. Therefore, if the motors Dl and D2 are rotated at an arbitrary angle, the wafer W can be transported to an arbitrary two-dimensional position within the range where the table T can reach.

Thus, for example, a wafer transfer arm placed in a vacuum chamber in a semiconductor manufacturing apparatus, for example, a device having a plurality of arms such as a scalar type or a frog redder type shown in the figure, particularly requires a plurality of rotary motors. It becomes. In a vacuum environment, the contact surface area with the outside world should be minimized, and at the same time, the number of mounting holes for motors, etc. should be minimized to make effective use of space. In addition, in order to transport the wafer W horizontally and with minimal vibration, it is necessary to firmly hold the moment acting on the tip of the arm with the rotor support. Therefore, a plurality of motors Dl and D2 are connected coaxially at the housing part, and the connecting part is tightly joined with a seal (tightly joined by welding, O-ring, metal gasket, etc.), and the space where the motor rotor is arranged It is also necessary to separate the housing from the external space.

[0050] In addition, in order to convey the wafer W horizontally and with little vibration, it is necessary to firmly hold the moment acting on the tips of the arms Al and A2 by the rotor support portion. In addition, when driving multiple axes in a vacuum environment, if the current rotation position of the arm is not recognized when the power is turned on, the arm Al, A2, etc. will be hit against the wall of the vacuum chamber or the shatter of the vacuum chamber. There is a possibility. A motor capable of meeting such a request will be described. FIG. 2 is a view of the configuration of FIG. Fig. 3 is a view of the configuration of Fig. 2 taken along line ΠΙ-ΠΙ and viewed in the direction of the arrow. The internal structure of the motor will be described in detail with reference to Figs. Since the basic configurations of the motors Dl and D2 are the same, only the motor D1 will be described, and the description of the configuration of the motor D2 will be omitted by giving the same reference numerals.

[0051] The hollow cylindrical main body 10 in which the flange 10a is installed on the surface plate G has a small circular plate 11 connected to the upper end thereof by a bolt. On the upper surface of the small disk 11, the large disk 12 is a bolt (not shown). It is more fixed. The center of the main body 10 can be used to pass wiring to the stator. The main body 10, small disk 11, and large disk 12 constitute the housing. A lid member 50 covering the opening of the main body 10 is hermetically bolted to the upper surface of the large disk 12. In addition, the resolver wiring HI for D2 and the motor wiring H2 for D2 are drawn out in the central opening of the main body 10 of the motor D2, and further, the resolver wiring H3 for D1 and D1 are inserted in the central opening of the main body 10 of the motor D1. The motor wiring H4 is drawn out, and these four wirings extend to the outside through the opening of the surface plate G.

[0052] On the flange 10a of the main body 10, a cylindrical partition wall 13 made of stainless steel (SUS304 or the like), which is a non-magnetic material, is attached coaxially to the main body 10. The upper part of the partition wall 13 is thin, and the upper end is bent inward in the radial direction, and is attached so as to be sandwiched by the small disk 11 by the disk 12. In addition, an O-ring OR is arranged between the members of the motor D1, as shown in the figure. Therefore, the internal space surrounded by the flange 10a of the main body 10, the partition wall 13, and the small disk 11 also has its external force. It is airtight. The partition wall 13 is not necessarily made of a nonmagnetic material. Further, instead of using an O-ring OR to seal the air, the members may be sealed by electron beam welding or laser beam welding.

[0053] The inner ring of a four-point contact ball bearing 14 used in vacuum is fitted to the lower outer periphery of the partition wall 13, and is attached to the partition wall 13 by an inner ring holder 15 fixed to the partition wall 13 with bolts. Yes. On the other hand, the outer ring of the bearing 14 is attached to the outer rotor 16 by an outer holder 17 that is fitted to the inner periphery of an outer rotor (also referred to as a main rotor) 16 and fixed to the outer rotor 16 with bolts. ing. That is, the outer rotor 16 is rotatably supported with respect to the partition wall 13. Bearing 14 is a four-point contact ball bearing that uses soft metal such as gold or silver plated on the inner ring and outer ring, and does not release gas even in vacuum, and is a four-point contact ball bearing. Force that can receive the moment of tilting of the outer rotor 16 from the arm A1 Not limited to the four-point contact type, cross rollers, cross balls, and cross taper bearings can also be used and may be used in a preload state. In order to improve lubricity, fluorine film treatment (DFO) may be performed.

An outer rotor magnet 18 is attached to the inner peripheral surface of the outer rotor 16. The outer rotor magnet 18 has a 24-pole configuration, and each of the 12 N-pole and S-pole magnets alternately has magnetic metal force. It is assembled to the knock yoke 19 with a gap through the wall 13.

FIG. 4 is an enlarged view of the arrow IV part of FIG. 3, and FIG. 5 is a view of the configuration of FIG. In the figure, the knock yoke 19 is configured by force with an annular rotor yoke (also simply referred to as a yoke) 19a made of a non-magnetic material and a yoke holder 19b fitted radially outward of the rotor yoke 19a. The rotor yoke 19a and the yoke holder 19b are fixed to each other by a Bonole 19c.

[0055] On the inner circumferential surface of the rotor yoke 19a, a plurality of outer rotor magnets (also referred to as magnetic poles) 18, which are permanent magnets, are arranged at intervals along the circumferential direction. The outer rotor magnets 18 are arranged so that the magnetic poles (N poles or S poles) are alternately directed inward in the radial direction, and a wedge-shaped spacer 19d is provided between the adjacent outer rotor magnets 18. Is arranged. The spacer 19d has a screw hole 19f, and a non-magnetic bolt 19e through which the radially outer cover of the rotor yoke 19a is threaded is screwed into the forceful screw hole 19f. It is attached to the inner peripheral surface.

[0056] One outer rotor magnet 18 has a shape in which circumferential end faces (also referred to as facing faces) 18a, 18a gradually approach each other in the radial direction as seen in the direction of FIG. . In other words, the interval between the opposing surfaces 18a, 18a of the adjacent outer rotor magnets 18, 18 increases inward in the radial direction as the force increases. On the other hand, the spacer 19d interposed between them has a shape in which the side surfaces 19g and 19g facing the facing surfaces 18a and 18a of the outer rotor magnets 18 and 18 gradually separate as they go radially inward. ing. The circumferential minimum distance C between the opposing surfaces 18a and 18a of the outer rotor magnets 18 and 18 is smaller than the maximum circumferential width W of the spacer 19d (W> C), and the outer rotor magnet 18 The parts forming the minimum circumferential interval C on the 18 opposing surfaces 18a, 18a are located radially outward from the part of the spacer 19d having the maximum width W. Further, gaps of ΔΖ2 are formed between the facing surfaces 18a and 18a and the side surfaces 19g and 19g, respectively.

[0057] The rotor yoke 19a may be magnetic stainless steel or nickel-plated iron. In this embodiment, the outer rotor magnet 18 is a segment type divided for each pole, and is made of a neodymium (Nd—Fe—B) type magnet having a high energy product. This neodymium magnet has a very small coefficient of linear expansion compared to iron, and is also brittle have. In the present embodiment, a nickel coating is applied to enhance corrosion resistance and to have high wear resistance. By applying such a surface treatment, it is difficult to occlude impure molecules, and sliding when fixing with the spacer 19d and generation of dust due to sliding wear when exposed to extreme high or low temperatures. Since it can prevent, it is suitable for a vacuum environment.

The shape of the outer rotor magnet 18 will be described in more detail. The shape on the outer diameter side in contact with the inner peripheral surface of the rotor yoke 19a is an arc shape having the same radius as the inner peripheral surface of the rotor yoke 19a or a slightly larger radius. In addition, the shape on the partition wall 13 side, which is the air gap side, is an arc shape having a radius such that the arc center of each magnet is the same as the rotation center when arranged on the rotor yoke 19a. The shapes of the circumferential end faces 18a and 18a are such that the flat force tangent intersection is close to the magnet. The axial end faces are a pair of parallel planes and are perpendicular to the axis. Each side is chamfered to prevent fine cracks and chips.

[0059] On the other hand, the rotor yoke 19a is made of low-carbon steel having high magnetism, and after processing and molding, considers the case where fouling and corrosion resistance are increased and is supported directly by the bearing, so that wear during replacement is avoided. Nickel plating is applied to prevent it. The shape of the outer rotor magnet 18 is slightly larger than the length of the axial end surface of the outer rotor magnet 18 and larger than the chamfering applied to the outer rotor magnet 18. Short flanges 19h and 19h are provided (see Fig. 5).

[0060] The gap between the outer rotor magnet 18 and the short flange portions 19h and 19h of the rotor yoke 19a is such a dimension that the gap remains even when exposed to the low temperature side of the use temperature and storage temperature of the motor.

The rotor yoke 19a has through holes 19j through which the bolts 19e for fastening the spacers 19d are passed in the radial direction with the same number and the same number of poles, and the bolt heads are sunk on the outer diameter surface. A counterbore 19k is provided. Further, a portion for fitting and fixing the rotating side of the bearing device and the yoke holder may be formed on the outer diameter side of the rotor yoke 19a, so that the inner ring and the yoke holder of the bearing device can be fitted. In such a case, using a grease grease lubricated four-point contact ball bearing, the inner ring, which is a rotating ring, can be tightly fitted to a yoke with high machining accuracy and a linear expansion coefficient that is almost the same as the bearing ring material of the bearing. With an intermediate fit, the outer ring, which is a rotating ring, is used frequently in aluminum or austenitic stainless steel in a vacuum environment. By making a clearance fit in the Tenres bearing holder, it is possible to prevent a decrease in the rotation accuracy of the bearing device and an increase in friction torque due to an increase in temperature.

[0061] The spacer 19d is made of austenitic stainless steel with less magnetism and is inserted between the magnetic poles to prevent the magnetic flux from short-circuiting and the interlinkage magnetic flux to the stator 29 from being reduced. It has a function of arranging the 18 on the rotor yoke 19a substantially equally. Further, since this material has high corrosion resistance, it is suitably used in a vacuum environment in which impure molecules are difficult to occlude. The spacer 19d has a trapezoidal columnar shape, and the portion in contact with the rotor yoke 19a has an arc shape having the same radius as the inner peripheral surface of the rotor yoke 19a or a slightly larger radius, like the outer rotor magnet 18. The spacer 19d has a screw hole 19f for fixing with the bolt 19e. The surface of the spacer 19d facing the partition wall 13 on the air gap side is flat, and the width from the part in contact with the rotor yoke 19a is the depth from the outer diameter of the rotor yoke 19a to the bolt head sinking into the rotor yoke counterbore 19k. Even if the dimensions are counted, the dimensions are located outside the inner diameter contact circle of each outer rotor magnet 18! /. The circumferential end surface of the spacer 19d is planar, but is substantially parallel to the circumferential end surface of the outer rotor magnet 18 that is equally distributed on the inner peripheral surface of the rotor yoke 19a and has a slight gap. Dimensions.

[0062] The tangential intersection angle between the outer rotor magnet 18 and the spacer 19d in the circumferential end face and the mutual clearance ΔΖ2 are based on the attractive force with the stator 29 even if the outer rotor magnet 18 floats in the air gap direction. Bolt 19e is a dimension that retains the clearance ΔZ2 even when exposed to the low temperature side of the operating temperature and storage temperature of the motor, and the bolt 19e has the same corrosion resistance as the spacer 19d. It is made of high and low magnetism! /, Austenitic stainless steel, which prevents the magnetic flux from short-circuiting and reducing the interlinkage magnetic flux to the stator 29.

[0063] The yoke holder 19b is made of an aluminum alloy having a small specific gravity as the metal material for reducing inertia, and has a fitting portion between the fitting portion with the outer diameter portion of the rotor yoke 19a and the end surface of the rotor yoke 19a. .

With such a configuration, after the outer rotor magnet 18 is attracted to the inner peripheral surface of the rotor yoke 19a, the outer rotor magnet 18 is removed by tightening the outer diameter side force of the spacer 19d with the bolt 19e. It can be easily arranged. [0064] Even when all the outer rotor magnets 18 and the spacers 19d are arranged, there is a clearance ΔΖ2 at the circumferential end faces of each other, so that the spacer 19d also lifts the inner circumferential surface force of the rotor yoke 19a. It can be securely fixed with bolts 19e without any problems. Furthermore, the portion of the spacer 19d in contact with the inner peripheral surface of the rotor yoke 19a is slightly larger than the inner radius of the rotor yoke 19a and has a slightly larger V! It is possible to make line contact at the entire surface or at two places and fix it more firmly.

[0065] On the other hand, since not only the circumferential end face of the outer rotor magnet 18 but also the axial end face has a clearance with respect to the rotor yoke 19a, the outer rotor magnet 18 is fixed only by a magnetic attraction force. Since the outer rotor magnet 18 is not mechanically constrained even when exposed to extremely high temperatures, it can be finely displaced with respect to the rotor yoke 19a, and there is a gap even when exposed to extremely low temperatures. And it does not receive compressive stress from short flange part 19h, 19h. Therefore, there is little possibility that the outer rotor magnet 18 will be cracked or chipped.

[0066] The portion of the outer rotor magnet 18 in contact with the inner peripheral surface of the rotor yoke 19a has the same radius as the inner peripheral surface of the rotor yoke 19a, and is a slightly larger arc having a radius. Line contact at the entire surface or at two locations. Therefore, wobbling is suppressed even when torque in the rotational direction due to energization of the stator 29 is applied.

In the state where the spacer 29 is fixed, even if a tensile force greater than the attractive force with the rotor yoke 19a is applied, the circumferential end surfaces of the outer rotor magnet 18 and the spacer 19d Since the shape is closer to the permanent magnet, the clearance ΔΖ2 or more with the spacer 19d cannot float, and the outer rotor magnet 18 does not come off to the gap side (partition wall 13 side). Further, in the state where the spacer 19d is fixed, the outer rotor magnet cannot be displaced because the gap between the short flange portions 19h and 19h of the rotor yoke 19a cannot be displaced even if it receives a force greater than the attracting force with the rotor yoke 19a in the axial direction. 18 does not come off in the axial direction. Further, since the outer rotor type is used, the outer rotor magnet 18 is not detached due to the centrifugal force accompanying the motor rotation.

[0067] The short flange portions 19h and 19h of the rotor yoke 19a are slightly higher than the chamfering made on the permanent magnet, and are much smaller than the radial thickness of the outer rotor magnet 18, so that the magnetic flux is short-circuited. The degradation of the motor performance due to can be minimized. Show me! However, when a thin outer rotor magnet is used or when it is desired to further reduce the short circuit of the magnetic flux, a non-magnetic material is provided between the axial end surface of the outer rotor magnet and the shoulders of the short flange portions 19h and 19h of the rotor yoke 19a. An annular member may be arranged. In that case, the short flanges 19h, 19h can be set without considering the short circuit of the magnetic flux.For example, an outer rotor magnet is buried between them to obtain the effect of preventing magnetic pole breakage during motor assembly. Is possible. In addition, if a strong annular member is cut at one point in the normal direction, it can be easily attached to the rotor 19a.

[0068] The width between the inner diameter side of the spacer 19d and the portion in contact with the rotor yoke 19a is not limited to the inner diameter contact of each permanent magnet, even if the depth of the sinked bolt head from the outer diameter of the rotor yoke 19a is added. The dimensions are located outside the circle. Therefore, in a state where the rotor yoke 19a is fitted to the yoke holder 19b, the spacer 19d is fixed! /, Even if the bolt 19e is loosened due to heat cycle or the like, it will not loosen more than the depth to the bolt head. Therefore, the spacer 19d can be prevented from interfering with the partition wall 13 to lock the motor.

[0069] The outer rotor magnet 18 of the present embodiment is a simple toroidal hexahedron similar to the case of fixing with an adhesive while having the above-described action, and uses unnecessary holes and holes related to magnetic pole fixing. There is no need to provide grooves, sides, and useless magnet volumes. Therefore, the motor performance and the component cost of the permanent magnet are equivalent to the case of fixing the magnetic pole with an adhesive. Conversely, since the attachment process can be omitted, the assembly cost can be reduced and the function can be easily guaranteed.

As described above, according to the present embodiment, the outer rotor magnet 18 is fixed to the inner peripheral surface of the rotor yoke 19a having magnetic force by magnetic force, so that gravity is easily displaced by torque caused by energization. There is nothing. The minimum circumferential distance C between the opposing surfaces 18a and 18a of the outer rotor magnets 18 and 18 is smaller than the maximum circumferential width W of the spacer 19d (W> C), and the outer rotor magnets The part forming the minimum circumferential distance C on the opposite faces 18a, 18a of 18, 18 is located radially outward from the part of the spacer 19d with the maximum width W, so use an adhesive. Even if unexpected vibrations or shocks occur, the outer rotor magnet 18 can be prevented from falling off or being displaced in the circumferential direction.Therefore, even when the motor D1 is placed in a vacuum, the released gas of the occluded impure molecules ( Outgas) It is possible to avoid atmospheric pollution. [0070] Further, when a clearance Δ / 2 is formed between the opposing surfaces 18a, 18a of the outer rotor magnets 18, 18 and the side surfaces 19g, 19g of the spacer 19d, the rotor yoke due to temperature change 1 Absorbs the difference in thermal expansion between the 9a and the outer rotor magnet 18 to avoid problems such as cracks and chipping.

Further, in FIG. 5, the rotor yoke 19a has short flange portions 19h and 19h extending radially inward at both ends in the axial direction, and the short flange portions 19h and 19h acting as contact portions are included in the rotor yoke 19a. Since it protrudes from the peripheral surface, the outer rotor magnet 18 is prevented from being displaced in the axial direction. A magnetic shield plate 30 is attached to the outer rotor 16 so as to cover the upper portion of the outer rotor magnet 18.

[0071] A stator 29 is arranged on the inner side in the radial direction of the partition wall 13 so as to face the inner peripheral surface of the outer rotor 16. The stator 29 is attached to the flange 10a of the main body 10 by the stator holder 20, and as shown in FIG. 3, 12 coils of each phase are arranged in a cylindrical shape in the order of U phase, V phase, and W phase. Lined up, so it contains a total of 36 coils. This coil is molded by a molding material and integrated. Since the stator 29 is thus arranged on the inner side of the partition wall 13, forced cooling such as water cooling or air cooling can be performed against coil heat generation or the like.

[0072] An inner rotor (also referred to as a sub-rotor) 21 is disposed on the radially inner side of the stator 29. The inner rotor 21 is rotatably supported by a ball bearing 23 with respect to a resolver holder 22 that is bolted to the outer peripheral surface of the main body 10. An inner rotor magnet 24 is attached to the outer peripheral surface of the inner rotor 21 via a knock 25. Like the outer rotor magnet 18, the inner rotor magnet 24 is composed of 24 poles, each consisting of 12 N poles and 12 S poles made of magnetic metal, and is assembled to the back yoke 25. Accordingly, the inner rotor 21 is rotationally driven by the stator 29 in synchronization with the outer rotor 16.

[0073] A detection rotor 26 for a detector for measuring a rotation angle is assembled on the inner periphery of the inner rotor 21, and resolvers 27 and 28 are attached to the outer periphery of the resolver holder 22 so as to face the rotor. Force In this embodiment, the high-resolution incremental resolver 27 and the absolute resolver 28 capable of detecting the position of the rotor in one rotation are arranged in two layers. Therefore, even when the power is turned on, the rotation angle of the detection rotor 26 can be determined and Since no return is required and the electrical phase angle of the magnet with respect to the coil is ineffective, rotation angle detection used for motor D1 drive current control is possible without using a pole detection sensor. .

[0074] In the high-resolution variable reluctance resolver used in the present embodiment, the detection rotor 26 has a plurality of slot tooth rows having a constant pitch, and the outer circumference of the magnetic poles of the stators of the resolvers 27 and 28 The surface is provided with teeth that are shifted in phase with respect to the detection rotor 26 at each magnetic pole in parallel with the rotation axis, and a coil is wound around each magnetic pole. When the detection rotor 26 rotates together with the inner rotor 21, the reluctance between the resolver 27 and 28 and the magnetic pole of the stator changes, and the fundamental component of the reluctance change becomes n periods in one rotation of the detection rotor 26. In this way, the change in reluctance is detected, digitized by the resolver control circuit shown in FIG. 6 and used as a position signal, so that the rotation angle (or rotation) of the detection rotor 26, that is, the inner rotor 21 is detected. Speed). The detection rotor 26 and the resolvers 27 and 28 constitute a detector.

In the present embodiment, the inner rotor 21 is driven to rotate in synchronization with the outer rotor 16 by the stator 29. Therefore, if the rotation angle of the inner rotor 21 can be detected, the inner rotor 21 is immediately started. The rotation angle of the outer rotor 16 can be obtained, whereby the drive control of the outer rotor 16 can be performed with high accuracy.

FIG. 7 is a block diagram showing a drive circuit of the motor D1. When a motor rotation command is input from an external computer, the motor control circuit DMC outputs a drive signal from the CPU to the three-phase amplifier (AMP), and the drive current is supplied to the three-phase amplifier (AMP) force motor D1. Supplied. As a result, the outer rotor 16 of the motor D1 rotates to move the arm A1. When the outer rotor 16 rotates, resolver signals are output from the resolvers 27 and 28 that have detected the rotation angle as described above. The CPU that is input after digital conversion of the signal by the resolver digital transformation ^ ^ (R DC) Determines whether the outer rotor 16 has reached the command position, and if it reaches the command position, stops the rotation of the outer rotor 16 by stopping the drive signal to the three-phase amplifier (AMP). Let As a result, servo control of the outer rotor 16 becomes possible.

[0076] In the present embodiment, since the absolute resolver 28 is used, the detection port The current flowing through the three-phase stator coil can be controlled according to the electrical angle of the motor 26 and the torque command. When a current is passed through the three-phase coils (U phase, V phase, W phase) of motor D1, the structure of the coreless motor is used. Torque can be generated. Originally, if the inner rotor 21 and the outer rotor 16 do not synchronize, each is supported by a rotatable bearing.

T: Torque generated on the outer rotor 16

o

I: Inertia including load on outer rotor 16 side

o

a: Acceleration of outer rotor 16

o

T: Torque generated to the inner rotor 21

I: Inner rotor 21 inertia

a: Acceleration of inner rotor 21

Since the arm A1 is attached to the outer rotor 16, Io: Since the inertia including the load on the outer rotor 16 side is large,

T = 1 X α

ο ο ο

Τ = Ι X α

Try to rotate at different accelerations.

[0077] The outer rotor 16 and the inner rotor 21 rotate in synchronization with each other, so that a predetermined torque is generated by the displacement of the rotation angle. Therefore, torque is transmitted from the inner rotor 21 to the outer rotor 16 when the inner rotor 21 without a loading load advances a minute angle phase in the torque generation direction with respect to the outer rotor 16, and as a result, the inner rotor 21 and the outer rotor Torque is transmitted so that the acceleration with 16 is the same, and the torque generated by the coil is generated according to the inertia.

[0078] In the present embodiment described above, since the motor D1 supports the moment force with the multipoint contact bearing 14, the wafer W is immediately transferred to the horizontal state even when the arm A1 having high rigidity is extended. it can. Also, since the inner ring of the bearing 14 is assembled to the thick member of the partition wall 13, the acting force hardly acts on the partition wall 13 and is directly applied to the main body 10, so that there is an extremely high risk that the partition wall 13 will be broken. Can be small.

Also, when driving multiple axes in a vacuum environment, the current arm A1 If the rotation position is not recognized, there is a possibility that the arm A1 etc. will hit the wall of the vacuum chamber or the shirt of the vacuum chamber. In this embodiment, however, the absolute position that detects the absolute position of one rotation of the rotating shaft is detected. A variable reluctance resolver consisting of a resolver 28 and an incremental resolver 27 that detects a rotational position with finer resolution is adopted! .

[0079] It should be noted that here, a force detector that employs a resolver for detecting the rotation of the inner rotor 21 can be arranged on the atmosphere side inside the partition wall 13, so that a servo motor generally used for high-precision positioning is highly accurate and smooth. An optical encoder adopted as a position detecting means for driving, a magnetic encoder using a magnetoresistive element, or the like can also be used. As described above, in the present embodiment, the same effect can be obtained even with the force inner rotor system described as an example of the motor of the rotor type. In that case, the tangent intersection of the outer rotor magnet 18 and the spacer 19d should be an angle at which the clearance ΔΖ2 or more with the spacer 19d cannot be lifted as described above. In addition, in order to prevent the bolt 19e from falling off and the outer rotor magnet 18 from being scattered, it is good to cover the rotor yoke with a non-magnetic thin tube.

[0080] The outer rotor magnet 18 uses a neodymium (Nd-Fe-B) magnet, and the force described using the example of nickel coating as a coating for enhancing corrosion resistance. It is appropriately changed depending on the environment in which it is not limited, and for example, a Samar-Co magnet (Sm-Co) magnet that is difficult to demagnetize at high temperatures depending on the temperature conditions during beta-out. Should be used in ultra-vacuum, a titanium nitride coating with a high outgas barrier should be applied.

[0081] Further, the rotor yoke 19b has been described using an example in which low-carbon steel is used as a material and nickel plating is performed. However, the material is not limited to the surface treatment and the material is not limited to the surface treatment. Especially for surface treatment, if it is used in an ultra-vacuum, it should be subjected to force-zen plating, clean soldering, titanium nitride coating, etc. with few pinholes.

In addition, the example of using a grease grease four-point contact ball bearing as the bearing device has been explained. However, the bearing device is not limited to this type, material, and lubrication method. It can be changed as appropriate and may be a cross roller bearing. Deep groove ball bearings may be structured to apply preload as an anguilla bearing, and when used in ultra-vacuum, a metal that does not emit gas, such as gold or silver plated soft metal on the race ring. Even if a lubricated one is used. Further, the material of the spacer 19d and the bolt 19e is appropriately changed depending on the manufacturing cost and the environment in which it is used.

The present invention has been described above with reference to the embodiment. However, the present invention should not be construed as being limited to the above embodiment, and can be appropriately changed or improved. The For example, the motor of this embodiment can be used not only in a vacuum atmosphere but also in an atmosphere outside the atmosphere. For example, in the case of a semiconductor manufacturing process, a reactive gas for etching may be introduced into the vacuum chamber after evacuation. In the motor of this embodiment, the inside and the outside are shielded by the partition wall. There is no risk of the motor coil or insulation material being etched! / ヽ.

Furthermore, the present invention is also applicable to ordinary motors other than the direct drive type motors D1 and D2 in the above-described embodiment.

[Second Embodiment]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 8 is a perspective view of a frog redder arm type transport device using a direct drive motor that works in this embodiment. In FIG. 8, two direct drive motors Dl and D2 are connected in series. The first arm A1 is connected to the rotor of the lower direct drive motor D1, and the first link L1 is pivotally connected to the tip of the first arm A1. On the other hand, the second arm A2 is connected to the rotor of the upper direct drive motor D2, and the second link L2 is pivotally connected to the tip of the second arm A2. The links LI and L2 are pivotally connected to a table T on which the wafer W is placed.

[0083] The force apparent from Fig. 8 If the rotors of the direct drive motors Dl and D2 rotate in the same direction, the table T also rotates in the same direction. If the powerful rotor rotates in the opposite direction, the table T The direct drive motors Dl and D2 are approaching or separating from each other. Therefore, if the direct drive motors Dl and D2 are rotated at an arbitrary angle, the wafer W can be transferred to an arbitrary two-dimensional position within a range where the table T can reach. Thus, for example, a wafer transporter disposed in a vacuum chamber in a semiconductor manufacturing apparatus. For example, a device having a plurality of arms such as a scalar type or a frog redder type shown in the figure requires a plurality of rotary motors. In a vacuum environment, the surface area of contact with the outside world should be minimized, and at the same time, the number of mounting holes for motors, etc., should be minimized to make effective use of space. Also, in order to transport the wafer W horizontally and with minimal vibration, it is necessary to hold the moment acting on the tip of the arm firmly at the rotor support. Therefore, a plurality of direct drive motors Dl and D2 are connected coaxially at the housing part, and the connection part is tightly joined with a seal (tightly joined by welding, O-ring, metal gasket, etc.), and the motor rotor is arranged. It is necessary to separate the open space from the housing external space.

[0084] In addition, in order to convey the wafer W horizontally and with little vibration, it is necessary to firmly hold the moment acting on the tips of the arms Al and A2 by the rotor support portion. In addition, when driving multiple axes in a vacuum environment, if the current rotation position of the arm is not recognized when the power is turned on, the arm Al, A2, etc. will be hit against the wall of the vacuum chamber or the shatter of the vacuum chamber. There is a possibility. A direct drive motor that can meet these requirements will be described.

FIG. 9 is a view of the configuration of FIG. 8 cut along the で -Π line and viewed in the direction of the arrow. FIG. 10 is a view of the configuration of FIG. 9 cut along the ΠΙ-ΠΙ line and viewed in the direction of the arrow. The internal structure of the direct drive motor will be described in detail with reference to FIGS. Since the direct drive motors D 1 and D 2 have the same basic configuration, only the direct drive motor D 1 will be described, and the description of the configuration of the direct drive motor D 2 will be omitted by attaching the same reference numerals.

[0086] The hollow cylindrical main body 10 in which the flange 10a is installed on the surface plate G has a small circular plate 11 connected to the upper end thereof by a bolt. On the upper surface of the small disk 11, a large disk 12 is fixed by a bolt (not shown). The center of the main body 10 can be used to pass wiring to the stator. The main body 10, small disk 11, and large disk 12 constitute the housing. A lid member 50 covering the opening of the main body 10 is hermetically bolted to the upper surface of the large disk 12. A cylindrical partition wall 13 made of stainless steel (SUS304 or the like), which is a non-magnetic material, is coaxially attached to the main body 10 on the flange 10a of the main body 10. The top of bulkhead 13 is thin Furthermore, the upper end is bent inward in the radial direction, and is attached in such a way that it is sandwiched by the small disk 11 by the disk 12. Incidentally, an O-ring OR is arranged between the members of the direct drive motor D1 as shown in the figure, and therefore the internal space surrounded by the flange 10a, the partition wall 13 and the small disk 11 of the main body 10 is External force is also airtight. The partition wall 13 is not necessarily made of a nonmagnetic material. Further, instead of using an O-ring OR, the members may be hermetically sealed by electron beam welding or laser beam welding.

[0087] The inner ring of a four-point contact ball bearing 14 used in vacuum is fitted to the lower outer periphery of the partition wall 13, and is attached to the partition wall 13 by an inner ring holder 15 fixed to the partition wall 13 with bolts. Yes. On the other hand, the outer ring of the bearing 14 is attached to the outer rotor 16 by an outer holder 17 that fits to the inner periphery of the outer rotor 16 and is bolted to the outer rotor 16. That is, the outer rotor 16 is rotatably supported with respect to the partition wall 13. The bearing 14 is a four-point contact ball bearing that uses a metal lubrication that is plated with a soft metal such as gold or silver on the inner ring and the outer ring to prevent outgassing even in a vacuum. Force that can receive moment in the tilting direction of the outer rotor 16 from the arm A1 Not limited to the four-point contact type, cross rollers, cross balls, cross taper bearings can also be used, and they may be used in a preload state Fluorine-based coating (DFO) may be performed to improve lubricity.

An outer rotor magnet 18 is attached to the inner peripheral surface of the outer rotor 16. The outer rotor magnet 18 is composed of 24 poles and 12 magnets of N poles and S poles alternately with magnetic metal force and assembled to the back yoke 19. The back yoke 19 may be made of magnetic stainless steel or iron-plated. In the present embodiment, the outer rotor magnet 18 is a nickel-plated magnet made of neodymium iron boron. Further, the outer rotor magnet 18 is fastened to the outer rotor 16 with a nonmagnetic metal wedge. Therefore, no resin such as adhesive is disposed, and even when the direct drive motor D1 is disposed in a vacuum, the released gas of the occluded impure molecules can be extremely reduced. A magnetic shield plate 30 is attached to the outer rotor 16 so as to cover the upper part of the outer rotor magnet 18.

[0089] On the radially inner side of the partition wall 13, facing the inner peripheral surface of the outer rotor 16, A stator 29 is arranged. The stator 29 is attached to the flange 10a of the main body 10 by the stator holder 20, and as shown in FIG. Lined up, so it contains a total of 36 coils. This coil is molded by a molding material and integrated. Since the stator 29 is thus arranged on the inner side of the partition wall 13, forced cooling such as water cooling or air cooling can be performed against coil heat generation or the like.

An inner rotor 21 is arranged on the inner side in the radial direction of the stator 29. The inner rotor 21 is rotatably supported by ball bearings 23 with respect to a resolver holder 22 that is bolted to the outer peripheral surface of the main body 10. An inner rotor magnet 24 is attached to the outer peripheral surface of the inner rotor 21 via a knock yoke 25. The inner rotor magnet 24 has a 24-pole configuration similar to the outer rotor magnet 18, and 12 N-pole and 12-pole magnets alternately have magnetic metal force and are assembled to the back yoke 25. Accordingly, the inner rotor 21 is rotationally driven by the stator 29 in synchronization with the outer rotor 16.

[0091] A detection rotor 26 for a detector that measures a rotation angle is assembled on the inner periphery of the inner rotor 21, and resolvers 27 and 28 are attached to the outer periphery of the resolver holder 22 so as to face the rotor. Force In this embodiment, a high-resolution incremental resolver 27 and an absolute resolver 28 capable of detecting the position of the rotor at one rotation are arranged in two layers. For this reason, even when the power is turned on, the rotation angle of the detection rotor 26 can be known, it is not necessary to return to the origin, and the electrical phase angle of the magnet with respect to the coil is ineffective. Rotation angle detection force to be used It is possible to use without using a pole detection sensor.

In the high-resolution variable reluctance resolver used in the present embodiment, the detection rotor 26 has a plurality of slot tooth rows having a constant pitch, and the outer circumference of the magnetic poles of the stators of the resolvers 27 and 28 The surface is provided with teeth that are shifted in phase with respect to the detection rotor 26 at each magnetic pole in parallel with the rotation axis, and a coil is wound around each magnetic pole. When the detection rotor 26 rotates together with the inner rotor 21, the reluctance between the resolver 27 and 28 and the magnetic poles of the stator changes, and the fundamental wave component of the reluctance change becomes n periods in one rotation of the detection rotor 26 Thus, the reluctance change is detected and the resolver control circuit shown in FIG. The rotation angle (or rotation speed) of the detection rotor 26, that is, the inner rotor 21, is detected by digitalizing and using it as a position signal. The detection rotor 26 and the resolvers 27 and 28 constitute a detector.

In the present embodiment, the inner rotor 21 is rotationally driven by the stator 29 in synchronism with the outer rotor 16. Therefore, if the rotation angle of the inner rotor 21 can be detected, the inner rotor 21 is immediately started. The rotation angle of the outer rotor 16 can be obtained, whereby the drive control of the outer rotor 16 can be performed with high accuracy.

FIG. 12 is a block diagram showing a drive circuit of the direct drive motor D1. When a motor rotation command is also input to an external computer, the motor control circuit DMC outputs a drive signal from the CPU to the three-phase amplifier (AMP), and the three-phase amplifier (AMP) force is also applied to the direct drive motor D1. A drive current is supplied. As a result, the outer rotor 16 of the direct drive motor D1 rotates to move the arm A1. When the outer rotor 16 rotates, resolver signals are output from the resolvers 27 and 28 that have detected the rotation angle as described above, and the CPU that has been input after digitally converting it with the resolver digital converter (RDC) It is determined whether or not the outer rotor 16 has reached the command position. When the command position is reached, the rotation of the outer rotor 16 is stopped by stopping the drive signal to the three-phase amplifier (AMP). This enables servo control of the outer rotor 16.

In the present embodiment, since the absolute resolver 28 is used, the current flowing through the three-phase stator coil can be controlled according to the electrical angle of the detection port 26 and the torque command. If a current is passed through the three-phase coils (U phase, V phase, W phase) of the direct drive motor D1, the structure of the coreless motor is used. Therefore, according to Fleming's left-hand rule, the outer rotor 16 and the inner motor 21 are Each can generate substantially the same torque. Originally, if the inner rotor 21 and the outer rotor 16 are not synchronized, each is supported by a rotatable bearing.

T: Torque generated on the outer rotor 16

o

I: Inertia including load on outer rotor 16 side

o

a: Acceleration of outer rotor 16

o

T: Torque generated to the inner rotor 21

I: Inner rotor 21 inertia a: Acceleration of inner rotor 21

T = 1 X α

ο ο ο

Τ = Ι X α

Try to rotate at different accelerations.

[0095] The outer rotor 16 and the inner rotor 21 rotate in synchronization with each other, so that a predetermined torque is generated by the displacement of the rotation angle. Therefore, torque is transmitted from the inner rotor 21 to the outer rotor 16 when the inner rotor 21 without a loading load advances a minute angle phase in the torque generation direction with respect to the outer rotor 16, and as a result, the inner rotor 21 and the outer rotor Torque is transmitted so that the acceleration with 16 is the same, and the torque generated by the coil is generated according to the inertia.

In the present embodiment described above, since the direct drive motor D1 supports the moment force with the multipoint contact bearing 14, the wafer W is straightened horizontally even when the arm A1 having high rigidity is extended. Can be transported. Since the inner ring of the bearing 14 is assembled to the thick member of the partition wall 13, the acting force hardly acts on the partition wall 13 and is directly applied to the main body 10, so that the risk of the partition wall 13 being broken is extremely high. Can be small.

Also, when driving multiple axes in a vacuum environment, if the current rotation position of the arm A1 is not recognized when the power is turned on, the arm A1 or the like may hit the wall of the vacuum chamber or the shatter of the vacuum chamber. However, in this embodiment, a variable reluctance resolver consisting of an absolute resolver 28 that detects the absolute position of one rotation of the rotating shaft and an incremental resolver 27 that detects a more precise rotational position is adopted. Therefore, the rotational position of the outer rotor 16, that is, the arm A 1 can be controlled with high accuracy.

[0097] Here, since a force detector that employs a resolver for detecting the rotation of the inner rotor 21 can be arranged on the atmosphere side inside the partition wall 13, a servo motor generally used for high-precision positioning is highly accurate and smooth. An optical encoder adopted as a position detecting means for driving, a magnetic encoder using a magnetoresistive element, or the like can also be used. FIG. 13 is a diagram showing a modification of the present embodiment. In the variation shown in FIG. The direct drive motors Dl and D2 are arranged in series (2 units in total). The direct drive motor has the same configuration as shown in Fig. 9 for the individual direct drive motors. The description will be omitted.

In the direct drive motor of the present embodiment, since the inner rotor is arranged inside the stator in the radial direction, the dimension in the axial direction can be reduced (thinned), so four pieces are conveyed in series as shown in FIG. Even if the device is configured, a compact configuration in the height direction can be provided. In addition, the thin structure increases the rigidity and avoids the risk of resonance, etc., which is advantageous for multi-axis use and can reduce the difference in control constant between the outer rotors. Furthermore, by using a stack of direct drive motors of the same shape, it is possible to replace only the direct drive motor in the event of a failure, providing excellent maintainability and minimizing the inventory of replacement parts.

FIG. 14 is a cross-sectional view similar to FIG. 9, showing a direct drive motor that can be used in the transport device shown in FIG. Since the direct drive motors Dl and D2 have the same basic configuration, only the direct drive motor D1 will be described, and the configuration of the direct drive motor D2 will be denoted by the same reference numerals and the description thereof will be omitted. In FIG. 14, a hollow cylindrical main body 110 in which a flange 110a is installed on a surface plate G has a small disk 111 connected to its upper end by a bolt. A large circular plate 112 is fixed to the outer peripheral side of the upper surface of the small circular plate 111 with a bolt (not shown). The center of the main body 110 can be used to pass wiring to the stator. The main body 110, the small disk 111, and the large disk 112 constitute a housing.

[0100] A cylindrical partition wall 113 made of stainless steel (SUS316L, etc.), which is a non-magnetic material, is inserted into the cylindrical mounting portion 110b formed on the flange 110a of the main body 110, so that the non-magnetic material is made of stainless steel. It is attached coaxially. The upper part of the partition wall 113 is thin, and the upper end is bent inward in the radial direction, and is attached to the small disk 111 together with the disk 112. Incidentally, an O-ring OR is arranged between the members of the direct drive motor D1 as shown in the figure, and therefore the internal space surrounded by the flange 110a of the main body 110, the partition wall 113, and the small disk 111 is External force is also airtight. Note that the partition wall 113 is not necessarily made of a nonmagnetic material. Further, instead of using an O-ring OR, the members may be hermetically sealed by electron beam welding or laser beam welding. [0101] The inner ring of a four-point contact ball bearing 114 used in vacuum is fitted to the lower outer periphery of the partition wall 113, and is attached to the partition wall 113 by an inner ring holder 115 fixed to the partition wall 113 with bolts. Yes. On the other hand, the outer ring of the bearing 114 is attached to the outer rotor 116 by an outer holder 117 that fits to the inner periphery of the outer rotor 116 and is fixed to the outer rotor 116 with a bolt. That is, the outer rotor 116 is supported rotatably with respect to the partition wall 113. The bearing 114 is a four-point contact ball bearing that uses soft metal such as gold and silver plated on the inner ring and outer ring to release metal even in vacuum, and is a four-point contact ball bearing. Force that can receive moment in the tilting direction of the outer rotor 116 from the arm A1 Not limited to the four-point contact type, cross rollers, cross balls, and cross taper bearings can also be used and may be used in a preload state In order to improve lubricity, fluorine film treatment (DFO) may be performed.

[0102] An outer rotor magnet 108 for magnetic coupling is attached to the center of the inner peripheral surface of the outer rotor 116. The outer rotor magnet 108 for magnetic coupling has a structure of 32 poles, and has a magnetic metal force in which 16 pieces of N pole and S pole magnets are alternately arranged, and is assembled to the knock yoke 109. The back yoke 109, which is a magnetic coupling rotor fitted and fixed to the outer rotor 116, may be magnetic stainless steel or iron-plated nickel. In the present embodiment, the outer rotor magnet 108 for magnetic coupling uses a nickel-plated magnet made of neodymium iron boron. Further, the outer rotor magnet 108 for magnetic coupling has a non-magnetic metal wedge fastened to the outer rotor 116 with a screw. Therefore, no grease such as adhesive is disposed, and even when the direct drive motor D1 is disposed in a vacuum, the released gas of the occluded impure molecules can be extremely reduced. A magnetic shield plate 103 is attached to the outer motor 116 so as to cover the upper part of the outer rotor magnet 108 for magnetic coupling.

Further, an outer rotor magnet 118 is attached to the upper part of the inner peripheral surface of the outer rotor 116. The outer rotor magnet 118 is composed of a magnetic metal in which 16 poles of N poles and S poles are alternately arranged in a 32 pole configuration, and is assembled to the back yoke 119. The back yoke 119 may be magnetic stainless steel or iron-nickel-plated. In the present embodiment, the outer rotor magnet 118 is a nickel-plated magnet made of neodymium iron boron. Yes. Further, the outer rotor magnet 118 has a nonmagnetic metal wedge fastened to the outer rotor 116 with a screw. Therefore, no resin such as adhesive is disposed, and even when the direct drive motor D1 is disposed in a vacuum, the released gas of the occluded impure molecules can be extremely reduced. A magnetic shield plate 130 is attached to the lower surface of the disc 112 so as to cover the upper portion of the outer rotor magnet 118.

[0104] On the radially inner side of the partition wall 113, a stateer 129 is arranged so as to face the outer rotor magnet 118. The stator 129 is attached to the main body 110. Although not shown, the stator 129 has a cylindrical shape with 3 slots for the U phase, 3 slots for the V phase, and 3 slots for the W phase. Slots are arranged. A magnetic shield plate 102 is attached to the outer rotor 116 so as to cover the top of the stator 129.

[0105] This 32-pole, 36-slot motor has a slot configuration that is four times that of a known art motor with fewer 8-coil and 9-slot cogginadas. In addition, since the configuration is an even multiple of the 8-pole 9-slot motor, the in-phase and the same pole are arranged on the diagonal line of the outer rotor 116. In the 8-pole 9-slot motor, the magnetic attraction force is unbalanced. 1S Radial force is generated in the bearing that supports it, and vibration may occur due to the rigidity of the bearing 114. Since the unbalanced force is canceled out by the same homologous poles on the diagonal line, the bearing 114 that supports the outer rotor 116 has a feature that suppresses the occurrence of vibration without using the unbalanced force.

Furthermore, the magnetic coupling inner rotor magnet 101 is arranged on the radially inner side of the partition wall 113 so as to face the magnetic coupling outer rotor magnet 108. The inner rotor magnet 101 for magnetic coupling is attached via a back yoke 125 to an inner rotor 121 that is rotatably supported via a bearing 123 with respect to a cylindrical mounting portion 110b of the flange 110a of the main body 110. Yes. The inner rotor magnet 101 for magnetic coupling, like the outer rotor magnet 108 for coupling, has a configuration of 32 poles and 16 magnets of N poles and S poles are alternately arranged. Therefore, the inner rotor magnet 101 for magnetic coupling and the outer rotor magnet 108 for magnetic coupling are fixed in relative rotation by the magnetic force attracting each other with the opposite poles facing each other with the partition wall 113 interposed therebetween, that is, between the two magnets. Based on the magnetic coupling force acting in a non-contact manner on the inner rotor 121, the inner rotor 121 It rotates in synchronization with the outer rotor 116.

[0107] A detection rotor 126 for a detector for measuring a rotation angle is assembled on the inner periphery of the inner rotor 121, and resolvers 127 and 128 are mounted on the outer periphery of the main body 110 so as to face the rotor. However, in the present embodiment, the high-resolution incremental resolver 127 and the absolute resolver 128 that can detect the position of the rotor in one rotation are arranged in two layers. For this reason, even when the power is turned on, the rotation angle of the detection rotor 126 can be known, the return to origin is unnecessary, and the electrical phase angle of the magnet with respect to the coil is ineffective, so the drive current control of the direct drive motor D1 This is possible without using the rotation angle detection force pole detection sensor used in the above.

In the high-resolution variable reluctance resolver used in the present embodiment, the detection rotor 126 has a plurality of slot tooth rows having a constant pitch, and the outer peripheral surfaces of the magnetic poles of the stators of the resolvers 127 and 128 Are provided with teeth shifted in phase with respect to the detection rotor 126 at each magnetic pole parallel to the rotation axis, and a coil is wound around each magnetic pole. When the detection rotor 126 rotates together with the inner rotor 121, the reluctance between the resolver 127 and 128 and the magnetic pole of the stator changes, and the fundamental wave component of the change in reluctance becomes n periods in one rotation of the detection rotor 126. Then, the change in reluctance is detected, digitized by the resolver control circuit shown in FIG. 11 and used as a position signal, so that the rotation angle (or rotation speed) of the detection rotor 126, that is, the inner rotor 121 is determined. It comes to detect. The detection rotor 126 and the resolvers 127 and 128 constitute a detector.

[0109] In the present embodiment, the inner rotor 121 is rotationally driven in synchronization with the outer rotor 116 via the magnetic coupling, so if the rotation angle of the inner rotor 121 can be detected, That force can also immediately determine the rotation angle of the outer rotor 116. Further, the direct drive motor D1 of the present embodiment is servo-controlled by a drive circuit as shown in FIG.

In the present embodiment, the magnetic shield plates 102 and 103 are configured so that the magnetic field generated between the stator 129 and the outer rotor magnet 118 is attracted between the magnetic coupling inner rotor magnet 101 and the magnetic coupling outer rotor magnet 108. It is provided to avoid disturbing the force and affecting the magnetic coupling action. However, stator 129 and outer rotor magnet 1 Since 18 magnetic poles are 32 poles, and the magnetic coupling inner rotor magnet 101 and the magnetic coupling outer rotor magnet 108 are also 32 magnetic poles, each has the same number of magnetic poles. Even if is omitted, the attractive force between the magnetic coupling inner rotor magnet 101 and the magnetic coupling outer rotor magnet 108 is not particularly disturbed. Therefore, the magnetic shield plates 102 and 103 are particularly effective when the magnetic poles of the stator 129 and the outer rotor magnet 118 are different from the magnetic poles of the magnetic coupling inner rotor magnet 101 and the magnetic coupling outer rotor magnet 108. is there.

[0110] By the way, when the outer rotor 116 vibrates due to the action of the magnetic coupling, the inner rotor 121 also vibrates and vibrates. Based on this, the resolver 127, 128 detects the angular position and controls the drive of the direct drive motor D1. Doing so may cause abnormal rotation of the outer rotor 116. This is called resonance of the magnetic coupling system. In this embodiment, the partition 113 is used to avoid an abnormal operation.

The principle of reducing the gain peak value of the resonance frequency of the magnetic coupling system using the eddy current loss of the partition wall 113 is shown below. FIG. 15 is a schematic diagram showing a state in which eddy current loss occurs in the partition wall 113. In FIG. 15, the outer rotor 116 is attached with the north pole of the outer magnet 108 for magnetic coupling, and the inner rotor 121 is fitted with the south pole of the inner magnet 101 for magnetic coupling. It is assumed that a magnetic coupling is formed by being opposed to each other with the partition wall 113 therebetween.

Here, when a predetermined electric power is supplied to a stator (not shown) in FIG. 15, the outer rotor 116 rotates in the direction of the arrow in the figure, but the inner coupling is performed by the magnetic coupling action based on the magnetic force penetrating the partition wall 113. The rotor 121 also rotates in the same direction. At this time, an eddy current A is generated on the a side (the side on which the magnetic flux density increases) of the partition wall 113 in the direction of weakening the magnetic flux. On the b side (the side where the magnetic flux density decreases) of the partition wall 113, a reverse eddy current B is generated in the direction of increasing the magnetic flux. This is the principle of eddy current, in which current is generated so as to prevent changes in magnetic flux.

FIG. 16 is a schematic diagram similar to FIG. 15 showing three magnets arranged in the direction, and shows a state in which a braking force against rotation is generated using eddy current. When the outer rotor 116 rotates relative to the direction indicated by the arrow in FIG. A current is generated to generate a magnetic flux. The magnetic flux generated by the eddy current generates a repulsive force with respect to the traveling direction of the magnet 108 mounted on the outer rotor 116. This eddy current increases as the rate of change of magnetic flux increases. Therefore, the eddy current increases as the permeability (magnetic resistance) of the partition wall 113 and the magnetic flux density and frequency of the magnet 108 increase. The partition wall 113 has a magnetic resistance value and an electrical resistance value specific to the material and shape force, and the product of the square of the electrical resistance value and the eddy current is the eddy current loss of the partition wall 113. Therefore, due to the eddy current loss of the partition wall 113 depending on the frequency, a damping resistance of the outer rotor 116 is generated at the time of magnetic coupling operation.

FIG. 17 is a block diagram of the motor control system when there is no partition wall, and FIG. 18 is a block diagram of the motor control system when there is a partition wall. When there is no partition wall 113, as shown in Fig. 17, the outer rotor 116 receives a reaction force only by the spring stiffness Kf of the magnetic coupling, and when there is the partition wall 113, as shown in Fig. 18, the magnetic coupling It can be seen that it receives a reaction force based on the spring stiffness Kf and the damping resistance Cf of the bulkhead.

Here, in the control system shown in FIG. 18, the transfer function of the motor speed corm with respect to the motor torque Te is expressed by the equation (1), and the resonance frequency and the attenuation factor are expressed by the equations (2), (3), (4) (5) Where Jm is the motor inertia, Jr is the resolver inertia, Kf is the spring force of the magnetic force coupling, Cf is the damping resistance of the magnetic coupling, ω a is the resonance frequency, ω ζ is the anti-resonance frequency, ζ and ζ are the damping rates is there.

a z

[0114] [Equation 1]

ω, _J__ 1 + 2 (. /) J + (1 /) ² j ²

G equation (1)

Jm + Jr l + 2 (. +

Kf {— + ~) expression)

Jm Jr equation (3)

Formula (4)

Formula (5)

[0115] The frequency characteristics of this transfer function G are shown in Figs. The gain is a force with a large peak value at the resonance point ω a. This is the damping factor ζ (or Cf: damping resistance due to eddy current loss)

a

As the power gets smaller, it gets bigger as it gets smaller. In other words, it can be seen that the smaller the eddy current loss with respect to the frequency, the greater the resonance gain peak value. If this resonance is large, the phase of the resolver angle detection signal and the phase of the outer rotor will be in opposite phases, which may cause the direct drive motor to oscillate. In order to avoid this, it is only necessary to increase the attenuation rate ζ. In this case, the damping resistance, which is the eddy current loss of the bulkhead, is increased.

The peak value can be made small by making it. Conventionally, oscillation could be prevented by using an angle signal using a notch filter for this resonance frequency in a motor control unit, etc. However, if the characteristic of the notch filter is too strong, the angle signal near the resonance frequency cannot be controlled. There is a risk of becoming. On the other hand, by using the eddy current loss of the partition wall, the resonance frequency peak value can be controlled by reducing the peak value of the resonance frequency. The spring stiffness of the magnetic coupling is expressed as shown in Fig. 21.

The biaxial coaxial direct drive motor according to the present invention can reduce the gain peak of the resonance frequency of the magnetic coupling by utilizing the eddy current loss of the partition wall. However, since eddy current loss leads to heat generation of the partition, it is desirable to determine the material and shape of the partition in consideration of heat generation. In addition, the damping resistance is determined along with the effect of a weak notch filter. Thus, control with less heat generation can be made possible.

The present invention has been described above with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and can be modified or improved as appropriate. For example, the direct drive motor of the present embodiment can be used not only in a vacuum atmosphere but also in an atmosphere outside the atmosphere. For example, in the case of a semiconductor manufacturing process, reactive gas for etching may be introduced into the vacuum chamber after evacuation, but in the direct drive motor of this embodiment, the inside and outside are shielded by the partition walls. Therefore, there is no possibility that the motor coil or the insulating material will be etched.

[Third embodiment]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 22 is a perspective view of a frog redder arm type transport device using a direct drive motor that works in the present embodiment. In FIG. 22, two direct drive motors Dl and D2 are connected in series. The first arm A1 is connected to the rotor of the lower direct drive motor D1, and the first link L1 is pivotally connected to the tip of the first arm A1. On the other hand, the second arm A2 is connected to the rotor of the upper direct drive motor D2, and the second link L2 is pivotally connected to the tip of the second arm A2. The links LI and L2 are pivotally connected to a table T on which the wafer W is placed.

The force apparent from Fig. 22 If the rotors of the direct drive motors Dl and D2 rotate in the same direction, the table T will also rotate in the same direction, and if the powerful rotor rotates in the opposite direction, the table T will become a direct drive It approaches or moves away from motors Dl and D2. Therefore, if the direct drive motors Dl and D2 are rotated at an arbitrary angle, the wafer W can be transferred to an arbitrary two-dimensional position within a range where the table T can reach. Thus, for example, a wafer transfer arm placed in a vacuum chamber in a semiconductor manufacturing apparatus, for example, an apparatus having a plurality of arms such as a scalar type or a frog redder type shown in the figure, particularly requires a plurality of rotary motors. It becomes. In a vacuum environment, the surface area of contact with the outside world should be minimized, and at the same time, the number of mounting holes for motors, etc., should be minimized to make effective use of space. Also, in order to transport wafer W horizontally and with minimal vibration, the moment acting on the tip of the arm is firmly held by the rotor support. It is necessary to have. Therefore, a plurality of direct drive motors Dl and D2 are connected coaxially at the housing part, and the connection part is tightly joined with a seal (tightly joined by welding, O-ring, metal gasket, etc.), and the motor rotor is arranged. It is necessary to separate the open space from the housing external space.

[0118] In addition, in order to transport wafer W horizontally and with less vibration, the moment acting on the tips of arms Al and A2 must be firmly held by the rotor support. In addition, when driving multiple axes in a vacuum environment, if the current rotation position of the arm is not recognized when the power is turned on, the arm Al, A2, etc. will be hit against the wall of the vacuum chamber or the shatter of the vacuum chamber. There is a possibility. A motor system in which a direct drive motor capable of meeting such requirements is connected to the same shaft will be described.

In the present embodiment, a surface magnet type 32-pole 36-slot outer rotor brushless type direct drive motor is used. The slot combination of 32 poles and 36 slots is generally known to have a large magnetic attraction force in the radial direction and large vibration during rotation. is there . 2 ⁿ times (n is an integer) cancels out the magnetic attractive force in the radial direction. Therefore, vibration during rotation can be achieved without increasing the roundness and coaxiality of the stator and rotor and the rigidity of the mechanical parts. Can be made small and cogging is inherently small, so that a very smooth rotation can be obtained. On the other hand, by using such a very multi-pole motor, the electrical angle cycle is greater than the mechanical angle cycle, so positioning controllability is good. Therefore, it is suitable for a direct drive motor that drives a robot apparatus without using a speed reducer as in the present invention. In addition, since the thickness and salient pole width of the stator connecting portion and the yoke thickness of the rotor can be reduced without lowering the total magnetic flux, the direct drive motor having a thin and large diameter and narrow width as in the present invention is used. Is preferred.

FIG. 23 is a view of the configuration of FIG. 22 cut along the Π-Π line and viewed in the direction of the arrow. With reference to FIG. 23, the internal structure of the two-axis motor system will be described in detail. First, the direct drive motor D1 will be described. A hollow cylindrical main body 12 fitted into the central opening 10a of the disk 10 installed on the surface plate G and fixed to each other by bolts 11 has a cup-shaped partition wall 13 attached to the upper end thereof. The center of the body 12 is used to pass the wiring to the stator. Can be used. The main body 12 and the disc 10 constitute a housing.

[0121] The partition wall 13 is made of stainless steel, which is a non-magnetic material, and extends from the peripheral edge of the partition wall 13 through the direct drive motors Dl and D2 in the axial direction. It consists of a cylindrical part (tubular part) 13b that is thinner than the existing disk part 13a. Therefore, the partition wall 13 is commonly used for the direct drive motors Dl and D2. The lower end of the cylindrical portion 13b is joined to the holder 15 so that it can be sealed by TIG welding, and the holder 15 is fixed to the disc 10 with bolts 16. Here, by making the welded portion of the cylindrical portion 13b and the holder 15 substantially the same thickness, it is possible to suppress heat from escaping only to the component on one side and to weld the fitting portion uniformly. . The contact surface between the holder 15 and the disk 10 is provided with a groove force that fits the seal member. After the seal member is fitted into the groove, the holder 15 and the disk 10 are fastened by the bolt 16. , Atmospheric side force is separated from the fastening part. The partition wall 13 is made of austenitic stainless steel SUS316, which has high corrosion resistance, and has a low magnetic property, and the holder 15 is made of SUS316 as well because of its weldability with the partition wall 13.

[0122] Further, the main body 12 and the partition wall 13, and the partition wall 13 and the holder 15 are hermetically joined, and the holder 15 and the disk 10 and the disk 10 and the surface plate G are respectively O-ring OR. Is airtight. Therefore, the internal space surrounded by the disc 10, the main body 12, and the partition wall 13 is airtight from the outside. The partition wall 13 is not necessarily made of a nonmagnetic material. Also, instead of using O-ring OR to seal the air, the parts may be sealed by electron beam welding or laser beam welding.

[0123] On the outer peripheral upper surface of the disc 10, a bearing holder 17 is fixed with bolts 18. The bearing holder 17 is fitted with an outer ring of a four-point contact ball bearing 19 that is used in a vacuum, and is fixed by bolts 20. On the other hand, the inner ring of the bearing 19 is fitted to the outer periphery of the first outer rotor 21 and is fixed by bolts 22. That is, the first outer rotor 21 is rotatably supported with respect to the partition wall 13, and a cylindrical member 23 that supports the arm A1 (FIG. 22) is fixed by the bolt 24. Here, the bolt 24 fastens the magnetic shield plate 25 extending inward in the radial direction together with the cylindrical member 23.

[0124] The disc 10 and the bearing holder 17 are made of austenitic stainless steel having high corrosion resistance, and the disc 10 also serves as a fitting fixing and sealing device with the surface plate G that is a chamber. A groove 10b for fitting the O-ring OR is provided on the lower surface thereof.

The magnetic shield plate 25 is subjected to nickel plating in order to enhance the anti-corrosion and corrosion resistance after press-forming the SPCC steel plate, which is a magnetic material. The effect of the bearing 19, which will be described later, is a four-point contact ball bearing that can apply radial, axial, and moment loads with a single bearing. By using this type of bearing, only one bearing for the direct drive motor D1 is required, so the two-axis coaxial motor system of the present invention can be made thinner. The bearing 19 is made of martensite stainless steel, which has high corrosion resistance for both the inner and outer rings and can be hardened by quenching. The rolling elements are ceramic balls, and the lubricant is vacuum grease that does not solidify even under vacuum.

[0125] The bearing 19 may be made of metal lubricated by plating a soft metal such as gold or silver on the inner ring and the outer ring so that outgassing is not generated even in vacuum, or a four-point contact ball. Because it is a bearing, it can receive a moment in the direction in which the first outer rotor 21 tilts from the arm A1, but it is not limited to the four-point contact type, and cross rollers, cross balls, and cross taper bearings can also be used. Yes, it can be used under preload conditions, or fluorine film treatment (DFO) can be performed to improve lubricity!ヽ.

[0126] The first outer rotor 21 includes a permanent magnet 21a, an annular yoke 21b made of a magnetic material to form a magnetic path, and a non-magnetic material for mechanically fastening the permanent magnet 21a and the yoke 21b. It consists of a wedge (not shown). Permanent magnet 21a has a configuration of 32 poles, each of which has 16 poles of N poles and S poles alternately made of magnetic metal, and is divided into segments. Each of the permanent magnets 21a has a sector shape. Although the inner and outer diameter arc centers are the same, the tangential intersection of the circumferential end faces is closer to the permanent magnet 21a, and the wedge is tightened from the outer diameter side of the yoke 21b with a screw to tighten the permanent magnet 21a to the yoke. Signed to 21b. With this configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. The permanent magnet 21a is a neodymium (Nd—Fe—B) based magnet having a high energy product, and has a nickel coating to enhance corrosion resistance. The yoke 21b is made of a low-carbon steel having high magnetism, and is plated with nickel to improve wear resistance and corrosion resistance and prevent wear during bearing replacement after processing and molding. In addition, the first outer rotor 21 has a surface for fitting and fixing the inner ring of the bearing 19 and the cylindrical member 23. The four-point contact ball bearing 19 is a very thin bearing, and its rotational accuracy and friction torque are greatly affected by differences in accuracy and linear expansion coefficient of the parts to be assembled. Therefore, in the case of the present embodiment, the inner ring of the bearing 19 which is a rotating ring is an interference fit or an intermediate fit to the yoke 21b which is easy to obtain processing accuracy and whose linear expansion coefficient is substantially the same as the bearing ring material of the bearing. The outer ring of the bearing 19, which is a fixed ring, is fitted to the austenitic stainless steel bearing holder or aluminum boss to prevent the bearing 19 from rotating and the friction torque from increasing due to temperature rise. ing.

A first stator 29 is disposed on the inner side in the radial direction of the partition wall 13 so as to face the inner peripheral surface of the first outer rotor 21. The first stator 29 is attached to a cylindrically deformed lower portion of a flange portion 12a extending in the radial direction at the center of the main body 12. The first stator 29 is formed of a laminated material of electromagnetic steel plates and is insulated from each salient pole. As a process, the motor coil is concentrated after the bobbin is fitted. The outer diameter of the first stator 29 is approximately the same as or smaller than the inner diameter of the partition wall 13.

The first inner rotor 30 is disposed on the radially inner side of the first stator 29. The first inner rotor 30 is rotatably supported by a ball bearing 33 with respect to a resolver holder 32 that is bolted to the outer peripheral surface of the main body 12. A permanent magnet 30a is attached to the outer peripheral surface of the first inner rotor 30 via a knock 30b. The permanent magnet 30a is composed of 32 poles in the same manner as the permanent magnet 21a of the first outer rotor 21, and 16 magnets of N poles and S poles are alternately made of magnetic metal. Accordingly, the first inner rotor 30 is rotated in synchronism with the first outer rotor 21 driven by the first stator 29.

[0130] The bearing 33 that rotatably supports the first inner rotor 30 is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, it is possible to reduce the thickness of the direct drive motor D1 because only one bearing is required. Since the interior of the partition wall 13 is an atmospheric environment, a bearing using grease lubrication based on general bearing steel and mineral oil can be applied.

Since the inside of the partition wall 13 is an atmospheric environment, the permanent magnet 30a is bonded and fixed to the back yoke 30b. Permanent magnet 30a is a neodymium (Nd-Fe-B) magnet with high energy product. Yes, with nickel coating to prevent wrinkle demagnetization. The yoke 30b is made of low-carbon steel with high magnetism, and is chromated to prevent fouling after machining.

[0131] Resolver rotors 34a and 34b are assembled on the inner periphery of the first inner rotor 30 as detectors for measuring the rotation angle, and the resolver stator 35 is disposed on the outer periphery of the resolver holder 32 so as to face it. In this embodiment, the high-resolution incremental resolver stator 35 and the absolute resolver stator 36 that can detect the position of the rotor in one rotation are arranged in two layers. /! For this reason, even when the power is turned on, the rotational angle of the absolute resolver rotor 34b is known, no return to origin is required, and the electrical phase angle of the magnet with respect to the coil increases, so the drive current of the direct drive motor D1 The rotation angle used for control can be detected without using a pole detection sensor.

[0132] The resolver holder 32 and the first inner rotor 30 are made of carbon steel, which is a magnetic material, so that electromagnetic noise from the motor field and motor coil is not transmitted to the resolver stators 35, 36 that are angle detectors. In order to prevent fouling after processing and molding, it is chromated.

The high-resolution variable reluctance resolver used in the present embodiment has an incremental resolver rotor 34a having a plurality of slot teeth having a constant pitch, and the outer peripheral surface of the incremental resolver stator 35. Are provided with teeth shifted in phase with respect to the incremental resolver rotor 34a at each magnetic pole parallel to the rotation axis, and a coil is wound around each magnetic pole. When the incremental resolver rotor 34a rotates together with the first inner rotor 30, the reluctance between the incremental resolver stator 35 and the magnetic pole changes, and the fundamental wave component of the change in reluctance is n cycles in one revolution of the incremental resolver rotor 34a. Thus, the change in reluctance is detected, digitalized by the resolver control circuit shown in FIG. 24, and used as a position signal, so that the rotational angle of the incremental resolving rotor 34a, that is, the first inner rotor 30 is obtained. (Or rotation speed) is detected. The resolver rotors 34a and 34b and the resolver stators 35 and 36 constitute a detector. [0133] According to the present embodiment, the first inner rotor 30 rotates at the same speed by the magnetic coupling action with respect to the first outer rotor 21, that is, rotates with the first outer rotor 21, so that the rotation of the first outer rotor 21 rotates. The corner can be detected through the bulkhead 13. Further, in the present embodiment, the resolver alone has the bearing 33 without using the parts forming the motor and the uzing. Therefore, the eccentricity adjustment with the resolver alone is performed before the resolver coil is assembled into the housing. Since accuracy adjustment such as position adjustment can be performed, there is no need to provide adjustment holes or notches on both flanges of the housing.

Next, the force for explaining the direct drive motor D2 Here, the main body 12 constitutes a housing. The cylindrical member 23 of the direct drive motor D1 described above extends upward to a position where it is superimposed on the direct drive motor D2, and the inner peripheral surface thereof is a four-point contact ball bearing 19 'used in a vacuum. The outer ring is fitted and fitted with bolts 20 '. On the other hand, the inner ring of the bearing 19 ′ is fitted to the outer periphery of the second outer rotor 21 ′ and is fixed by the bolt 22 ′. Here, the bolt 22 'and the magnetic shield plate 41 extending inward in the radial direction are fastened together. The second outer rotor 21 ′ is rotatably supported with respect to the partition wall 13, and a ring-shaped member 23 ′ that supports the arm A2 (FIG. 22) is fixed by a bolt 24 ′. Further, the bolt 24 'fastens the magnetic shield plate 25 extending inward in the radial direction together with the ring-shaped member 23'.

[0135] The magnetic shield plates 41 and 25 'are subjected to nickel plating in order to improve the anti-corrosion and corrosion resistance after press molding the SPCC steel plate, which is a magnetic material. The magnetic shield plates 41 and 25 are interposed between the first outer rotor 21 and the second outer rotor 21 to form a magnetic shield and prevent mutual rotation due to magnetic flux leakage from them. . That is, the magnetic shield plate 25 ′ is fastened to the yoke 21b ′ with the ring-shaped member 23 ′, which is a non-magnetic material, interposed therebetween, thereby preventing unnecessary magnetic circuits from being generated. Since the magnetic shield plates 41 and 25 can prevent magnetic interference between the rotors, it is possible to achieve a configuration in which the overall shaft length is suppressed while being a biaxial coaxial motor system. The magnetic shield plate 41 prevents foreign matter from being attracted from the outside.

[0136] The bearing 19 'is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, direct drive motor D2 Since only one bearing is required, the biaxial coaxial motor of the present invention can be thinned. The inner and outer rings are made of martensitic stainless steel, which has high corrosion resistance and can be hardened by quenching. The rolling elements are ceramic balls, and the lubricant is vacuum grease that does not solidify even under vacuum.

The bearing 19 'may be made of a metal lubrication that is plated with a soft metal such as gold or silver on the inner ring and the outer ring and does not release outgas even in vacuum, or a four-point contact ball bearing. As a result, it is possible to receive a moment in the direction in which the first outer rotor 21 from the arm A1 tilts. However, not only a four-point contact type, but also a cross roller, a cross ball, and a cross taper bearing can be used. It can be used under preload conditions, or it can be treated with fluorine coating (DFO) to improve lubricity!ヽ.

[0137] The second outer rotor 21 'mechanically fastens the permanent magnet 21a', the annular yoke 21b 'made of a magnetic material to form a magnetic path, and the permanent magnet 21a' and the yoke 21b '. It is made up of a wedge (not shown). Permanent magnet 21a 'is a segment type with a configuration of 32 poles, with 16 N-pole and S-pole magnets alternately made of magnetic metal and divided into poles, each of which has a sector shape. The center of the arc of the inner and outer diameters is the same force.By making the tangent intersection of the circumferential end face closer to the permanent magnet 21a ', the wedge is tightened from the outer diameter side of the yoke 21b' by screwing the permanent magnet 21a ' It is fastened to the yoke 21b '. With this configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. Permanent magnet 21a 'is a high energy product neodymium (Nd-Fe-B) based magnet, which is coated with nickel to enhance corrosion resistance. Yoke 21b 'is made of low-carbon steel with high magnetism and is plated with nickel in order to improve wear resistance and corrosion resistance and prevent wear during bearing replacement after processing and molding.

[0138] Further, the second outer rotor 21 'has a surface for fitting and fixing the inner ring of the bearing 19' and the ring-shaped member 23 '. The four-point contact ball bearing 19 'is a very thin bearing, and its rotational accuracy and friction torque are greatly affected by differences in the accuracy and linear expansion coefficient of the assembled parts. Therefore, in the case of the present embodiment, the inner ring of the bearing 19 ′ is tightly fitted or intermediately fitted to the yoke 21b, which is easy to obtain machining accuracy and has the same linear expansion coefficient as the bearing ring material of the bearing. Outer ring of austenitic stainless steel bearing holder and aluminum By adopting a clearance fit to the made boss, the bearing 19 'is prevented from lowering the rotational accuracy and preventing the friction torque from increasing due to temperature rise.

[0139] On the radially inner side of the partition wall 13, a second stator 29 'is disposed so as to face the inner peripheral surface of the second outer rotor 21'. The second stator 29 ′ is attached to the upper part of the flange 12 a that extends in the radial direction in the center of the main body 12, and is formed of a laminated material of electromagnetic steel sheets, and each salient pole is insulated. As shown, the motor coil is concentrated after the bobbin is fitted. The outer diameter of the second stator 29 ′ is approximately the same as or smaller than the inner diameter of the partition wall 13.

[0140] A second inner rotor 30 'is arranged on the radially inner side of the second stator 29'. The second inner rotor 30 ′ is rotatably supported by a ball bearing 33 ′ with respect to a resolver holder 32 ′ bolted to the outer peripheral surface of the main body 12. A permanent magnet 30a ′ is attached to the outer peripheral surface of the second inner rotor 30 ′ via a back yoke 30b ′. The permanent magnet 30a ′ has a configuration of 32 poles, like the permanent magnet 21a ′ of the second outer rotor 21 ′, and has 16 magnetic poles each having N poles and S poles alternately. Accordingly, the second inner rotor 30 ′ is rotationally driven by the second stator 29 ′ in synchronization with the second outer rotor 21 ′.

[0141] The bearing 33 ′ that rotatably supports the first inner rotor 30 ′ is a four-point contact ball bearing that can apply radial, axial, and moment loads with a single bearing. By using this type of bearing, only one bearing is required, so the direct drive motor D2 can be made thinner. Since the inside of the partition wall 13 is an atmospheric environment, a bearing using grease lubrication based on general bearing steel and mineral oil can be applied.

Since the inside of the partition wall 13 is an atmospheric environment, the permanent magnet 30a ′ is bonded and fixed to the back yoke 30b ′. The permanent magnet 30a 'is a neodymium (Nd-Fe-B) magnet with a high energy product and is coated with nickel to prevent demagnetization due to defects. Yoke 30b 'is made of low-carbon steel with high magnetism, and is chromated to prevent fouling after machining.

[0142] Resolver rotors 34a 'and 34b are assembled on the inner periphery of the second inner rotor 30' as detectors for measuring the rotation angle, and are arranged on the outer periphery of the resolver holder 32 'so as to face each other. The resorno stator 35 ′, 36 ′ Incremental resolver stator 35 with high performance and an absolute resolver stator 36 'that can detect the position of the rotor in one rotation are arranged in two layers. For this reason, even when the power is turned on, the rotational angle of the absolute resolver rotor 34b 'is known, no return to origin is required, and the electrical phase angle of the magnet with respect to the coil is different. This is possible without using a pole detection sensor.

[0143] The resolver holder 32 'and the second inner rotor 30' are magnetic bodies so that electromagnetic noise from the motor field and the motor coil is not transmitted to the resolver stators 35 'and 36' which are angle detectors. Carbon steel is used as a material, and chromate plating is applied after processing to prevent fouling.

According to the present embodiment, the second inner rotor 30 ′ rotates at the same speed by the magnetic coupling action with respect to the second outer rotor 21 ′, that is, rotates with the rotation angle of the second outer rotor 21 ′. Can be detected through the partition wall 13. Further, in this embodiment, the parts forming the motor, the bearing 33 is provided as a single resolver without using uzing, and therefore, the eccentricity adjustment with the single resolver is performed before being incorporated into the housing. Since it is possible to adjust the accuracy of the resolver coil position, etc., there is no need to provide separate adjustment holes or cutouts on both flanges of the housing.

In the high resolution variable reluctance resolver used in the present embodiment, the incremental resolver rotor 34a ′ has a plurality of slot tooth rows having a constant pitch, and the incremental stator resolver stator 35, On the outer peripheral surface, teeth whose phases are shifted with respect to the incremental resolver rotor 34a ′ by each magnetic pole in parallel with the rotation axis are provided, and a coil is wound around each magnetic pole. When the incremental resolver rotor rotor 34a rotates integrally with the second inner rotor 30 ', the reluctance between the magnetic poles of the incremental resolver stator 35 changes, and the fundamental wave component of the reluctance change is changed by one revolution of the incremental resolver rotor 34a'. The change in reluctance is detected so that there are n cycles, digitalized by the resolver control circuit shown in FIG. 24 as an example, and used as a position signal, so that the incremental resolver rotor 34a ′, that is, the second inner rotor 30 The rotation angle (or rotation speed) of 'is detected. Resolver rotors 34a, 34b, and resolver stators 35, 36 'And configure the detector.

[0145] In the present embodiment, the bottom 13a of the partition wall 13 is not restrained in the axial direction with respect to the main body 12, so that a dimensional error is caused in the partition wall 13 due to dimensional accuracy, mechanical accuracy, and temperature change. Even if a deformation occurs, the bottom 13a is not pressed against or pulled out of the main body 12, so the axial stress and bending stress of the partition wall 13 can be relieved, thereby preventing seal failure and breakage. Can do. In addition, since it is not necessary to process the depth of the bottom 13a and the length of the main body 12 with high precision, a lower cost direct drive motor can be provided.

Further, by making the cylindrical portion 13b thin, it is easy to ensure the amount of magnetic flux density between the rotor and the stator.

Furthermore, according to the present embodiment, since the magnetic shield plates 25 and 41 are arranged between the first outer rotor 21 and the second outer rotor 21 ′, mutual magnetic interference is prevented. Suppresses and avoids malfunctions such as erroneous driving and surroundings. Further, the outer peripheral edge 12b of the flange portion 12a extending between the direct drive motors D1 and D2 in the main body 12 is made of carbon steel, which is a magnetic material, between the first stator 29 and the second stator 29 ′. So that the first outer rotor 21 or the second outer rotor 21 does not generate a thrust in the wrong rotation direction due to the influence of the leakage magnetic flux! / Functions as a magnetic shield.

Note that the first stator 29 and the second stator 29 ′ are arranged vertically with the flange portion 12 a as the center, and a resolver is arranged on the radially inner side. The main body 12 has a hollow structure, and the flange portion 12a has at least one radial through hole 12d communicating with the center through which the motor wiring is drawn out to the center of the main body 12. It has a structure. On the other hand, at least one notch 12e, 12e is provided at each end of the main body 12, and the resolver wiring is drawn out to the center of the main body 12 through these. With this structure, the direct motor D1 resolver, the stator 29, the direct motor D2 stator 29, and the resolver can be arranged in this order from the housing side. In addition, the angle of the stator and resolver can be adjusted. Therefore, if a facility for rotationally driving the reference outer rotor is prepared separately, the main body 12 incorporating the stator and resolver is set in the facility, so that the resolution with respect to the stator can be accurately achieved. Since the angle of the bar can be adjusted, it is possible to prevent the angle positioning accuracy from being lowered due to the deviation of the commutation, and to improve the compatibility of the drive control circuit with the two-axis coaxial motor of the present invention.

FIG. 25 is a block diagram showing a drive circuit for the direct drive motors Dl and D2. When a motor rotation command is also input to the external computer force, the motor control circuit DMC1 for the direct drive motor D1 and the motor control circuit DMC2 for the direct drive motor D2 are each sent from the CPU to the three-layer amplifier (AMP). The drive signal is output, and the drive current is supplied to the direct drive motors Dl and D2 with a three-layer amplifier (AMP) force. As a result, the outer rotors 21 and 21 ′ of the direct drive motors Dl and D1 rotate independently to move the arms A1 and A2 (FIG. 22). When the outer rotor 21, 21 'rotates, the resolver signal is output from the resolver stator 35, 36, 35, 36, which has detected the rotation angle as described above, and is output to the resolver digital converter (RDC). The CPU input after digital conversion judges whether or not the outer rotor 21, 21 'has reached the command position, and when it reaches the command position, it stops the drive signal to the 3-layer amplifier (AMP). Stop rotation of outer ports 21, 21 '. This enables servo control of the outer rotors 21, 21 '.

[0149] When driving multiple axes in a vacuum environment, if the current rotation position of arms A1 and A2 is not recognized when the power is turned on, the arm A1 or the like is attached to the wall of the vacuum chamber or the shatter of the vacuum chamber. In this embodiment, the absolute resolver stators 36 and 36 'that detect the absolute position of one rotation of the rotating shaft, and the incremental resolver stator 35 and that detect a rotational position with finer resolution are used in this embodiment. 35, a variable reluctance resolver is used, so that the rotational position of the outer rotors 21 and 21, that is, the arms Al and A2, can be controlled with high accuracy.

[0150] It should be noted that here, a force detector that employs a resolver for detecting the rotation of the inner rotor 30 can be placed on the atmosphere side inside the partition wall 13, so a servo motor generally used for high-precision positioning is highly accurate and smooth. An optical encoder adopted as a position detecting means for driving, a magnetic encoder using a magnetoresistive element, or the like can also be used. FIG. 26 is a cross-sectional view similar to FIG. 23 that works on the second embodiment. In this embodiment Accordingly, different parts from the embodiment shown in FIGS. 23 to 25 will be described, and parts having similar functions will be denoted by the same reference numerals and description thereof will be omitted. In the configuration of FIG. 26, the inner rotor, the stator, and the resolver are shown as a simple integrated force. These are the same as the configuration shown in FIG.

[0151] In the present embodiment, bolts are used for the stepped portion 11Oa of the upper disc portion 110 attached to the upper surface of the cylindrical main body 112, and the annular portion 113a is hermetically sealed via the O-ring OR. Are connected. The lower portion of the annular portion 113a is a flange portion 113c that is thin and extends radially outward. The upper end of the thin cylindrical portion 113b is TIG welded to the bent outer edge. The thickness of the attachment portion of the annular portion 113a is thicker than the thickness of the flange portion 113c and the thin cylindrical portion 113b. The lower end of the thin cylindrical portion 113b is TIG welded to the holder 15 in the same manner as in the above embodiment. The annular portion 113a, the flange portion 113c, the thin cylindrical portion 113b, and the holder 15 constitute a partition wall 113. Further, the disc part 110, the main body 112 and the disc 10 constitute a nosing.

[0152] In the present embodiment, the upper surface of the upper disc portion 110 is closed by the lid member 101, and the bearing holder 107 attached to the outer periphery thereof supports the bearing 19 '. Therefore, the cylindrical member 123 of the direct drive motor D1 does not extend to the direct drive motor D2 side. The bearing holder 117 of the direct drive motor D1 is integrated with the disc 10. The upper disk part 110, the lid member 101, and the bearing holder 107 are made of V-austenitic stainless steel having high corrosion resistance.

[0153] The mounting outer peripheral surface of the upper disc portion 110 of the bearing holder 107 is located on the inner side in the radial direction from the thin cylindrical portion 113b. Therefore, if the bearing holder 107 is removed from the upper disc portion 110, 2 The two outer rotors 21 and 21 ′ can be removed upward without disassembling the upper disk part 110. Therefore, it is possible to facilitate work that does not require disassembly of the airtight structure during maintenance.

In the present embodiment, the thickness of the flange portion (connecting portion) 113c is thinner than the thickness of the annular portion (attachment portion) 113a of the partition wall 113, so that the dimensional accuracy, mechanical accuracy, and temperature change Even if an axial expansion / contraction stress is generated in the partition wall 113 due to the above, the flange portion 113c is deformed, so that the axial stress and bending stress of the partition wall 113 can be relaxed. Thus, it is possible to prevent a sealing failure or destruction. Further, since it is not necessary to process the annular portion 113a and the upper disk portion 110 and the main body 12 to which the annular portion 113a is attached with high precision, a lower cost direct drive motor can be provided.

FIG. 27 is a cross-sectional view similar to FIG. 23 that works on the third embodiment. With respect to the present embodiment, different parts from the embodiment of FIG. 26 will be described, and parts having similar functions will be denoted by the same reference numerals and description thereof will be omitted. In the configuration of FIG. 27, the inner rotor, the stator, and the resolver are shown as a simple integrated force. These are the same as the configuration shown in FIG.

In the present embodiment, the annular portion 213a is hermetically coupled to the step portion 11 Oa of the upper disc portion 110 attached to the upper surface of the cylindrical main body 112 through an O-ring OR using bolts. is doing. The lower portion of the annular portion 213a is a thin plate-like flange portion 213c extending radially outward in a wave shape, and is formed by TIG welding the upper end of the thin cylindrical portion 213b to the bent outer edge. The thickness of the attachment portion of the annular portion 213a is thicker than the thickness of the flange portion 213c and the thin cylindrical portion 213b. The lower end of the thin-walled cylindrical portion 213b is TIG welded to the holder 15 as in the above-described embodiment. The annular portion 213a, the flange portion 213c, the thin cylindrical portion 213b, and the holder 15 constitute a partition wall 213. Further, the disk part 110, the main body 112, and the disk 10 constitute a housing.

Also in the present embodiment, the thickness of the flange portion (connecting portion) 213c is thinner than the thickness of the annular portion (attachment portion) 213a of the partition wall 213, and further, the annular portion 213a The flange portion 213c that connects the thin cylindrical portion 213b is corrugated, so even if axial expansion and contraction stress occurs in the partition wall 213 due to dimensional accuracy, mechanical accuracy, and temperature changes, the flange portion By deforming 213c, axial stress and bending stress of the partition wall 213 can be relieved, thereby preventing seal failure and breakage. Further, since it is not necessary to process the annular portion 213a and the upper disk portion 110 and the main body 12 to which the annular portion 213a is attached with high accuracy, a lower cost direct drive motor can be provided.

FIG. 28 is a cross-sectional view similar to FIG. 23 that works on the fourth embodiment. With respect to the present embodiment, different parts from the embodiment of FIG. 26 will be described, and parts having similar functions will be denoted by the same reference numerals and description thereof will be omitted. Note that the configuration shown in FIG. However, the inner rotor, the stator, and the resolver are shown as a simple integrated force. These are the same as the configuration shown in FIG.

In the present embodiment, the annular portion 313a is hermetically coupled to the step portion 11 Oa of the upper disk portion 110 attached to the upper surface of the cylindrical main body 112 through an O-ring OR using bolts. is doing. The cylindrical portion 313e has a shape in which a small cylindrical portion 313c and a large cylindrical portion 313b having substantially the same thickness are connected by a flange portion 313d. The upper portion of the cylindrical portion 313c is an inner peripheral surface of the annular portion 313a. TIG welded. The thickness of the annular portion 313a is thicker than the thickness of the cylindrical portion 313e. The lower end of the large cylindrical portion 313b is TIG welded to the holder 15 as in the above-described embodiment. The annular portion 313a, the tubular portion 313e, and the holder 15 constitute a partition wall 313. The disk portion 110, the main body 112, and the disk 10 constitute a housing.

[0157] Also in the present embodiment, the thickness of the tubular portion 313e is thinner than the thickness of the annular portion (attachment portion) 313a of the partition wall 313, which causes dimensional accuracy, mechanical accuracy, and temperature changes. Therefore, even when an axial expansion / contraction stress is generated in the partition wall 313, the flange portion 313d is deformed, so that the axial stress and bending stress of the partition wall 313 can be relaxed. Destruction can be prevented. Further, since it is not necessary to process the annular portion 313a and the upper disk portion 110 and the main body 12 to which the annular portion 313a is attached with high accuracy, a lower cost direct drive motor can be provided.

In the above embodiment, the force described using the example using the surface magnet type 32-pole 36-slot outer rotor brushless motor is not limited to this type of motor.

Any brushless motor can be applied, and other magnetic pole types such as a permanent magnet embedded type, other slot combinations, or an inner rotor type may be used. Further, as a countermeasure against interference of each axis, a configuration may be adopted in which the number of rotor poles and the number of slots of adjacent axes in the axial direction are different. For example, in the case of 2-axis coaxial, the first axis is 32 poles and 36 slots, the second axis is 24 poles and 27 slots, and in the case of 4-axis coaxial, the first and third axes are 32 poles and 3 6 slots. If the two axes and the fourth axis are configured to have 24 poles and 27 slots, mutual interference such as generation of thrust in the rotational direction to the rotor and magnetic coupling device due to the magnetic field of each axis can be prevented. [0159] Also, the permanent magnet of the rotor is a neodymium (Nd-Fe-B) -based magnet, and the example in which nickel coating is applied as a coating for improving corrosion resistance has been described. This material is not limited to the surface treatment, but is changed as appropriate depending on the environment in which it is used. For example, samarium-cobalt (Sm'Co) is difficult to demagnetize at high temperatures depending on the temperature conditions during beta-out System magnets should be used, and if used in ultra-vacuum, a titanium nitride coating with a high outgas barrier should be applied.

[0160] Also, the yoke is made of low-carbon steel and explained with an example of nickel plating. This material is not limited to the surface treatment, and is appropriately changed depending on the environment used. Especially for surface treatment, if it is used in ultra-vacuum, it should be applied with force with few pinholes such as Zen plating, clean soldering, and titanium nitride coating.

The method for fastening the permanent magnet to the yoke has been described using an example in which a non-magnetic wedge is tightened from the outer diameter side of the yoke with a screw, but it may be changed as appropriate depending on the environment in which it is used. May be bonded or other fastening methods.

[0161] Also, bearings 19 and 19 'have been described using an example of grease lubricated four-point contact ball bearings for vacuum, but this is not limited to this type, material and lubrication method. It can be changed as appropriate depending on conditions, rotational speed, etc., and it can be a cross roller bearing. In the case of a 4-axis coaxial motor, it can be supported by another bearing to further increase mechanical rigidity. If a multi-point contact bearing cannot be used, such as when rotating at high speeds, a bearing that supports the rotor of each shaft and another bearing may be configured to apply preload as deep groove ball bearings or angular bearings. When used in an ultra-vacuum, it is possible to use a metal-lubricated material that does not emit gas, such as a metal ring plated with a soft metal such as gold or silver.

[0162] The inner rotor functioning as a magnetic coupling has been described in the form of using a permanent magnet and a back yoke. However, the material and shape of the permanent magnet and the back yoke are not limited thereto. For example, depending on the mass of the resolver and the frictional torque of the bearing, the number of poles may not be the same as that of the rotor, or may not be the same. A salient pole that does not use a permanent magnet may be used. In addition, an example using a resolver as an angle detector has been described. Therefore, it is appropriately changed, and for example, an optical rotary encoder may be used.

[0163] In addition, an example in which grease lubricated four-point contact ball bearings are used as the bearings 33 and 33 'that rotatably support the rotation side of the angle detector has been described, but this type and the lubrication method are limited. However, if the multi-point contact bearing cannot be used, such as high-speed rotation or reduction of friction torque, an anguilla bearing is a deep groove ball bearing. A structure may be used in which two are arranged for each axis to apply preload.

In addition, the material, shape, and manufacturing method of the structural parts and partition walls arranged in and out of the other partition walls are appropriately changed depending on the manufacturing cost, the environment used, the load conditions, the configuration, and the like.

[0164] Although the present invention has been described above with reference to the embodiments, it should be understood that the present invention should not be construed as being limited to the above-described embodiments but can be modified or improved as appropriate. The For example, the direct drive motor of the present embodiment can be used not only in a vacuum atmosphere but also in an atmosphere outside the atmosphere. For example, in the case of a semiconductor manufacturing process, reactive gas for etching may be introduced into the vacuum chamber after evacuation, but in the direct drive motor of this embodiment, the inside and outside are shielded by the partition walls. Therefore, there is no possibility that the motor coil or the insulating material will be etched.

[Fourth embodiment]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 29 is a perspective view of a frog redder arm type transfer device using a motor system including a direct drive motor that works in the present embodiment. In Fig. 29, two direct drive motors Dl and D2 are connected in series. A first arm A1 is connected to the rotor of the lower direct drive motor D1, and a first link L1 is pivotally connected to the tip of the first arm A1. On the other hand, the second arm A2 is connected to the rotor of the upper direct drive motor D2, and the second link L2 is pivotally connected to the tip of the second arm A2. The links LI and L2 are pivotally connected to a table T on which the wafer W is placed.

[0165] The force apparent from Fig. 29 If the rotors of the direct drive motors Dl and D2 rotate in the same direction, the table T also rotates in the same direction, and the powerful rotor rotates in the opposite direction. For example, the table T approaches or moves away from the direct drive motors Dl and D2. Therefore, if the direct drive motors Dl and D2 are rotated at an arbitrary angle, the wafer W can be transferred to an arbitrary two-dimensional position within a range where the table T can reach. Thus, for example, a wafer transfer arm placed in a vacuum chamber in a semiconductor manufacturing apparatus, for example, an apparatus having a plurality of arms such as a scalar type or a frog redder type shown in the figure, particularly requires a plurality of rotary motors. It becomes. In a vacuum environment, the contact surface area with the outside world should be minimized, and at the same time, the number of mounting holes for motors, etc. should be minimized to make effective use of space. Also, in order to transport the wafer W horizontally and with minimal vibration, it is necessary to hold the moment acting on the tip of the arm firmly at the rotor support. Therefore, a plurality of direct drive motors Dl and D2 are connected coaxially at the housing part, and the connection part is tightly joined with a seal (tightly joined by welding, O-ring, metal gasket, etc.), and the motor rotor is arranged. It is necessary to separate the open space from the housing external space.

[0166] In addition, in order to transport wafer W straight horizontally and with less vibration, the moment acting on the tips of arms Al and A2 must be firmly held by the rotor support. In addition, when driving multiple axes in a vacuum environment, if the current rotation position of the arm is not recognized when the power is turned on, the arm Al, A2, etc. will be hit against the wall of the vacuum chamber or the shatter of the vacuum chamber. There is a possibility. A motor system in which a direct drive motor capable of meeting such requirements is connected to the same shaft will be described.

In this embodiment, a surface magnet type 32-pole 36-slot outer rotor type brushless type direct drive motor is used. The slot combination of 32 poles and 36 slots is generally known to have a large magnetic attraction force in the radial direction and large vibration during rotation. is there . 2 ⁿ times (n is an integer) cancels out the magnetic attractive force in the radial direction. Therefore, vibration during rotation can be achieved without increasing the roundness and coaxiality of the stator and rotor and the rigidity of the mechanical parts. Can be made small and cogging is inherently small, so that a very smooth rotation can be obtained. On the other hand, by using such a very multi-pole motor, the electrical angle cycle is greater than the mechanical angle cycle, so positioning controllability is good. Thus, as in the present invention This is suitable for a direct drive motor that drives a robot apparatus without using a speed reducer. In addition, since the thickness and salient pole width of the stator connecting portion and the yoke thickness of the rotor can be reduced without lowering the total magnetic flux, the direct drive motor having a thin and large diameter and narrow width as in the present invention is used. Is preferred.

FIG. 30 is a view of the configuration of FIG. 29 taken along the Π-Π line and viewed in the direction of the arrow. With reference to FIG. 30, the internal structure of the two-axis motor system will be described in detail. First, the direct drive motor D1 will be described. A hollow cylindrical main body 12 joined coaxially to the central opening 10a of the disk 10 installed on the surface plate G and fixed to each other by bolts 11 has a cup-shaped partition wall 13 attached to the upper end thereof. The center of the main body 12 can be used for wiring to the stator. The main body 12 and the disk 10 constitute a housing.

[0169] The partition wall 13 is made of stainless steel, which is a non-magnetic material, and extends from the peripheral edge of the wall portion 13a fitted to the main body 12 to the direct drive motors Dl and D2 in the axial direction. It consists of a thin cylindrical portion 13b. Therefore, the partition wall 13 is commonly used for the direct drive motors Dl and D2. The lower end of the cylindrical portion 13b is joined to a holder 15 so as to be sealed by TIG welding, and the holder 15 is fixed to the disc 10 with bolts 16. Here, by setting the welded portion of the cylindrical portion 13b to substantially the same thickness, it is possible to prevent heat from escaping only to the component on one side and to weld the fitting portion uniformly. The contact surface between the holder 15 and the disk 10 is grooved so that the seal member is inserted into the groove. After the seal member OR is inserted into the groove, the holder 15 and the disk 10 are tightened with the bolts 16 to tighten them. The part is separated from the atmosphere side. The partition wall 13 is made of austenitic stainless steel SUS316, which has high corrosion resistance, and is less magnetic. The holder 15 is also made of SU S316 because of its weldability with the partition wall 13.

[0170] Further, the partition wall 13 and the holder 15 are hermetically joined, and the holder 15 and the disk 10 and the disk 10 and the surface plate G are hermetically sealed by O-rings OR, respectively. Therefore, the internal space surrounded by the disk 10 and the partition wall 13 is also hermetically sealed. The partition wall 13 is not necessarily made of a nonmagnetic material. Further, instead of using an O-ring OR, the members may be hermetically sealed by electron beam welding or laser beam welding.

A bearing holder 17 is formed on the outer peripheral upper surface of the disk 10 in a body-like manner. Bearing holder 17 The outer ring of a four-point contact ball bearing 19 used in a vacuum is fitted in a fitting manner and fixed by a bolt 20. On the other hand, the inner ring of the bearing 19 is fixed to a double cylindrical cylindrical member 23 fitted with the first outer rotor member 21 and fixed by a bolt 22 that fastens the first outer rotor member 21 together. . That is, the first outer rotor member 21 is rotatably supported with respect to the partition wall 13 by the cylindrical member 23 that supports the arm A1 (FIG. 29). The first outer rotor member 21 and the cylindrical member 23 constitute an outer rotor.

[0171] The disc 10 (including the bearing holder 17) is made of austenitic stainless steel with high corrosion resistance. The disc 10 also serves as a fitting and fixing device with the surface plate G, which is a chamber, and a sealing device. A groove 10b for inserting the O-ring OR is provided on the lower surface thereof.

Bearing 19 is a four-point contact ball bearing that can apply radial, axial, and moment loads with a single bearing. By using this type of bearing, only one bearing for the direct drive motor D1 is required, so the two-axis coaxial motor system of the present invention can be made thinner. The bearing 19 is made of martensite stainless steel, which has high corrosion resistance for both the inner and outer rings and can be hardened by quenching. The rolling elements are ceramic balls, and the lubricant is vacuum grease that does not solidify even under vacuum.

[0172] The bearing 19 may be made of metal lubricated by plating a soft metal such as gold or silver on the inner ring and the outer ring so as not to release outgas even in vacuum, or a four-point contact ball. Since it is a bearing, the force that can receive the moment in the direction in which the first outer rotor member 21 tilts from the arm A1 is not limited to a four-point contact type, and cross roller, cross ball, and cross taper bearings can also be used. It can be used in a preloaded state, or fluorine film treatment (DFO) can be performed to improve lubricity.

Further, the cylindrical member 23 has a surface for fitting and fixing the inner ring of the bearing 19. The four-point contact ball bearing 19 is a very thin bearing, and its rotational accuracy and friction torque are greatly affected by differences in the accuracy and linear expansion coefficient of the assembled parts. Therefore, in the case of the present embodiment, the inner ring of the bearing 19 which is a rotating ring is tightly fitted or intermediately fitted to the cylindrical member 23 which is easy to obtain machining accuracy and whose linear expansion coefficient is substantially the same as the bearing ring material of the bearing. By fitting the outer ring of the bearing 19 that is a fixed ring into the austenitic stainless steel bearing holder or the aluminum holder 17 with a clearance fit, the rotational accuracy of the bearing 19 decreases or the temperature increases. It is configured to prevent an increase in friction torque due to ascent.

[0174] The first outer rotor member 21 is composed of a permanent magnet 21a, an annular yoke 21b made of a magnetic material to form a magnetic path, and a non-magnetic material for mechanically fastening the permanent magnet 21a and the yoke 21b. It is made up of a wedge (not shown) that also has power. Permanent magnet 21a has a configuration of 32 poles, each of which has 16 poles of N poles and S poles, each of which is a magnetic metal cage, and is divided into segments, each of which has a fan shape. . Although the inner and outer diameter arc centers are the same, the tangential intersection of the circumferential end face is closer to the permanent magnet 21a, so that the wedge is tightened with a screw from the outer diameter side of the yoke 21b, thereby fixing the permanent magnet 21a to the yoke 21b. It is concluded to. With this configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. Permanent magnet 21a is a high energy product, neodymium (Nd-Fe-B) based magnet, which is nickel-coated to enhance corrosion resistance. The yoke 21b is made of low-carbon steel with high magnetism, and is nickel-plated to improve wear resistance and corrosion resistance after machining and to prevent wear during bearing replacement.

[0175] On the radially inner side of the partition wall 13, the first stator 29 is arranged so as to face the inner peripheral surface of the first outer rotor member 21. The first stator 29 is attached to a cylindrically deformed lower portion of a flange portion 12a extending in the radial direction at the center of the main body 12, and is formed of a laminated material of electromagnetic steel plates. After the bobbin is fitted, the motor coil is concentrated. The outer diameter of the first stator 29 is approximately the same as or smaller than the inner diameter of the partition wall 13.

[0176] The first inner rotor 30 is disposed adjacent to and parallel to the first stator 29. The first inner rotor 30 is rotatably supported by ball bearings 33 with respect to a resolver holder 32 bolted to the outer peripheral surface of the main body 12. A permanent magnet 30a is attached to the outer peripheral surface of the first inner rotor 30 via a knock 30b. As with the permanent magnet 21a of the first outer opening member 21, the permanent magnet 30a has a 32-pole configuration, and each of the 16 N-pole and S-pole magnets alternately has a magnetic metal force. Accordingly, the first inner rotor 30 is rotated in synchronism with the first outer rotor member 21 driven by the first stator 29.

[0177] The bearing 33 that rotatably supports the first inner rotor 30 is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. Use this type of bearing Therefore, the direct drive motor D1 can be made thinner because only one bearing is required. Since the inside of the partition wall 13 is an atmospheric environment, a bearing using grease lubrication based on general bearing steel and mineral oil can be applied.

Since the inside of the partition wall 13 is an atmospheric environment, the permanent magnet 30a is bonded and fixed to the back yoke 30b. Permanent magnet 30a is a high energy product neodymium (Nd-Fe-B) magnet with nickel coating to prevent demagnetization due to defects. The yoke 30b is made of low-carbon steel with high magnetism, and is chromated to prevent fouling after machining.

[0178] Resolver rotors 34a and 34b are assembled as detectors for measuring the rotation angle on the inner circumference of the first inner rotor 30, and the resolver stator 35 is disposed on the outer circumference of the resolver holder 32 so as to face it. In this embodiment, the high-resolution incremental resolver stator 35 and the absolute resolver stator 36 that can detect the position of the rotor in one rotation are arranged in two layers. /! For this reason, even when the power is turned on, the rotational angle of the absolute resolver rotor 34b is known, no return to origin is required, and the electrical phase angle of the magnet with respect to the coil increases, so the drive current of the direct drive motor D1 The rotation angle used for control can be detected without using a pole detection sensor.

[0179] The resolver holder 32 and the first inner rotor 30 are made of carbon steel, which is a magnetic material, so that electromagnetic noise from the motor field and motor coil is not transmitted to the resolver stators 35, 36 that are angle detectors. In order to prevent fouling after processing and molding, it is chromated.

The high-resolution variable reluctance resolver used in the present embodiment has an incremental resolver rotor 34a having a plurality of slot teeth having a constant pitch, and the outer peripheral surface of the incremental resolver stator 35. Are provided with teeth shifted in phase with respect to the incremental resolver rotor 34a at each magnetic pole parallel to the rotation axis, and a coil is wound around each magnetic pole. When the incremental resolver rotor 34a rotates integrally with the first inner rotor 30, the reluctance between the magnetic poles of the incremental resolver stator 35 changes, and the fundamental wave component of the reluctance change is changed by one rotation of the incremental resolver rotor 34a. The change in reluctance is detected so that there are n cycles, digitalized by the resolver control circuit shown in FIG. 31 and used as a position signal, so that the incremental resolver rotor 34a, that is, the first inner rotor 30 The rotation angle (or rotation speed) is detected. The resolver rotors 34a and 34b and the resolver stators 35 and 36 constitute a detector.

[0180] According to the present embodiment, the first inner rotor 30 rotates at the same speed by the magnetic coupling action with respect to the first outer rotor member 21, that is, the first outer rotor member 21 rotates. Can be detected through the partition wall 13. Further, in the present embodiment, the resolver alone has the bearing 33 without using any part of the motor that forms the motor. Therefore, the eccentricity of the resolver alone can be adjusted before the resolver coil is assembled into the housing. Since accuracy adjustment such as position adjustment can be performed, it is not necessary to provide adjustment holes and notches on both flanges of the housing.

[0181] Next, the force for explaining the direct drive motor D2 Here, the main body 12 constitutes a housing. The cylindrical member 23 of the direct drive motor D1 described above extends upward to a position where it is superimposed on the direct drive motor D2, and the inner peripheral surface thereof is a four-point contact ball bearing 19 'used in a vacuum. The outer ring is fitted and fitted with bolts 20 '. On the other hand, the inner ring of the bearing 19 ′ is fixed by a bolt 22 ′ that fits around the circumferential surface of a double cylindrical ring-shaped member 23 ′ and fastens the second outer rotor member 21 ′ together. That is, the second outer rotor member 21 ′ is rotatably supported with respect to the partition wall 13 by a ring-shaped member 23 ′ that supports the arm A 2 (FIG. 29). The second outer rotor member 21 ′ and the ring-shaped member 23 ′ constitute an outer rotor.

[0182] Bearing 19 'is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, since the direct drive motor D2 requires only one bearing, the biaxial coaxial motor of the present invention can be made thinner. The inner and outer rings are made of martensitic stainless steel, which has high corrosion resistance and can be hardened by quenching. The rolling elements are ceramic balls, and the lubricant is vacuum grease that does not solidify even under vacuum.

The bearing 19 'is plated with a soft metal such as gold or silver on the inner and outer rings, However, it is possible to use a metal-lubricated one that does not release outgas, and since it is a four-point contact ball bearing, it can receive a moment in the direction in which the first outer rotor member 21 from the arm A1 tilts. Force Not limited to the four-point contact type, cross rollers, cross balls, and cross taper bearings can also be used. They can be used under preload conditions, or fluorine film treatment (DFO) can be performed to improve lubricity. ! ヽ.

[0183] Further, the ring-shaped member 23 'has a surface for fitting and fixing the inner ring of the bearing 19'. The four-point contact ball bearing 19 'is a very thin bearing, and its rotational accuracy and friction torque are greatly affected by differences in the accuracy of the assembled parts and the linear expansion coefficient. Therefore, in the case of the present embodiment, the inner ring of the bearing 19 ′ has an interference fit or an intermediate fit on the yoke 21b which is easy to obtain machining accuracy and whose linear expansion coefficient is substantially the same as the bearing ring material of the bearing. The outer ring is fitted with an austenitic stainless steel bearing holder or aluminum boss to prevent a decrease in rotational accuracy of the bearing 19 'and an increase in friction torque due to temperature rise.

[0184] The second outer rotor member 21 'mechanically fastens the permanent magnet 21a', the annular yoke 21b 'made of a magnetic material to form a magnetic path, and the permanent magnet 21a' and the yoke 21b '. It is made up of a wedge (not shown) that also has non-magnetic strength. Permanent magnet 21a 'is a segment type with a configuration of 32 poles, each consisting of 16 magnets of N poles and S poles alternately made of magnetic metal, and each pole is segmented. The inner and outer diameter arc centers are the same, but the tangential intersection of the circumferential end face is closer to the permanent magnet 21a ', so that the wedge is tightened from the outer diameter side of the yoke 2 lb' by tightening the screw with the permanent magnet 21a. 'Is fastened to York 21b. With such a configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. The permanent magnet 21a 'is a neodymium (Nd-Fe-B) magnet with a high energy product, and has a nickel coating to improve corrosion resistance. Yoke 21b 'is made of low-carbon steel with high magnetism and is plated with nickel to improve wear resistance and corrosion resistance and prevent wear during bearing replacement after processing and molding.

[0185] On the radially inner side of the partition wall 13, the second stator 29 'is disposed so as to face the inner peripheral surface of the second outer rotor member 21'. The second stator 29 'is located at the center of the main body 12. Attached to the cylindrically deformed upper portion of the flange portion 12a extending in the radial direction, it is made of a laminated material of electromagnetic steel plates, and a motor coil is concentrated around each salient pole after a bobbin is fitted as an insulation treatment Has been. The outer diameter of the second stator 29 ′ is substantially the same as or smaller than the inner diameter of the partition wall 13.

[0186] A second inner rotor 30 'is disposed adjacent to and parallel to the second stator 29'. The second inner rotor 30 ′ is rotatably supported by a ball bearing 33 ′ with respect to a resolver holder 32 ′ that is bolted to the outer peripheral surface of the main body 12. A permanent magnet 30a ′ is attached to the outer peripheral surface of the second inner rotor 30 ′ via a knock yoke 30b ′. The permanent magnet 30a ′ has a configuration of 32 poles, like the permanent magnet 21a ′ of the second outer rotor member 21 ′, and 16 magnets of N poles and S poles are alternately made of magnetic metal. Accordingly, the second inner rotor 30 ′ is driven to rotate in synchronization with the second outer rotor member 21 ′ by the second stateer 29 ′.

[0187] The bearing 33 'that rotatably supports the first inner rotor 30' is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, only one bearing is required, so the direct drive motor D2 can be made thinner. Since the inside of the partition wall 13 is an atmospheric environment, a bearing using grease lubrication based on general bearing steel and mineral oil can be applied.

[0188] Resolver rotors 34a 'and 34b' are assembled on the inner circumference of the second inner rotor 30 'as detectors for measuring the rotation angle, and the outer circumference of the resolver holder 32' is opposed to it. In addition, in this embodiment, a high resolution incremental resolver stator 35 and an absolute resolver stator 36 ′ that can detect which position of the rotor is in one rotation in this embodiment. Are arranged in two layers. Therefore, even when the power is turned on, the rotation angle of the absolute resolver rotor 34b ' Since the electrical phase angle of the magnet with respect to the coil is ineffective, the relative rotational angle of the direct drive motor D2 can be achieved without using a pole detection sensor.

[0189] The resolver holder 32 and the second inner rotor 30 are magnetic bodies so that electromagnetic noise from the motor field and the motor coil is not transmitted to the resolver stators 35 'and 36' which are angle detectors. Carbon steel is used as a material, and chromate plating is applied after processing to prevent fouling.

According to the present embodiment, the second inner rotor 30 ′ rotates at the same speed by the magnetic coupling action with respect to the second outer rotor member 21 ′. Can be detected through the partition wall 13. Further, in the present embodiment, the resolver alone has the bearing 33 ′ without using the parts forming the motor, and therefore the eccentricity adjustment with the resolver alone is not performed before the housing is assembled. Because it is possible to adjust the accuracy of the housing position, etc., it is not necessary to provide a separate adjustment hole or notch on both flanges of the housing.

In the high resolution variable reluctance resolver used in the present embodiment, the incremental resolver rotor 34a ′ has a plurality of slot tooth rows having a constant pitch, and the outer circumference of the incremental resolver stator 35. The surface is provided with teeth that are shifted in phase with respect to the incremental resolver rotor 34a ′ at each magnetic pole parallel to the rotation axis, and a coil is wound around each magnetic pole. When the incremental resolver port 34a rotates integrally with the second inner rotor 30 ', the reluctance between the magnetic poles of the incremental resolver stator 35 changes, and the basic reluctance change occurs with one rotation of the incremental resolver rotor 34a. The reluctance change is detected so that the wave component has n cycles, is digitalized by the resolver control circuit shown in FIG. 31 and used as a position signal, so that the incremental resolver rotor 34a ′, that is, the first 2The rotation angle (or rotation speed) of the inner rotor 30 'is detected. The resolver rotors 34a, 34b and the resolver stators 35, 36 constitute a detector.

[0191] According to the present embodiment, the outer rotor of the direct drive motor D2 (the second outer rotor 21 and the ring-shaped member 23), the outer rotor of the other direct drive motor D1 (the first outer Side rotor 21 and cylindrical member 23) are supported by bearing 19 ', so if the outer rotor of direct drive motor D2 is removed, the powerful outer rotor is supported! If the outer rotor of the direct drive motor D1 can be exposed and then removed, the bearing 19 supporting the powerful outer rotor can be exposed, and these can be easily inspected and removed, thus improving maintainability. Furthermore, since only the outer rotor outside the partition wall 13 has to be removed, a leak check or the like is not required at the time of reassembly without the need to remove the partition wall structure, thereby improving the assemblability.

[0192] The first stator 29 and the second stator 29 'are vertically arranged around the flange portion 12a, and the resolver is arranged radially inward thereof. The main body 12 has a hollow structure, and the flange portion 12a has at least one radial through hole 12d communicating with the center through which the motor wiring is drawn out to the center of the main body 12. It has a structure. On the other hand, at least one notch 12e, 12e is provided at each end of the main body 12, and the resolver wiring is drawn out to the center of the main body 12 through these. With this structure, the direct motor D1 resolver, the stator 29, the direct motor D2 stator 29, and the resolver can be arranged in this order from the housing side. In addition, the angle of the stator and resolver can be adjusted. Therefore, if a separate facility for rotationally driving the reference outer rotor is prepared, the angle of the resolver relative to the stator can be adjusted with high accuracy by setting the main body 12 incorporating the stator and resolver in the facility. Therefore, it is possible to prevent the angle positioning accuracy from being lowered due to the deviation of the commutation, and to improve the compatibility of the drive control circuit with the two-axis coaxial motor of the present invention.

FIG. 32 is a block diagram showing a drive circuit for the direct drive motors Dl and D2. When a motor rotation command is also input to the external computer force, the motor control circuit DMC1 for the direct drive motor D1 and the motor control circuit DMC2 for the direct drive motor D2 are each sent from the CPU to the three-layer amplifier (AMP). The drive signal is output, and the drive current is supplied to the direct drive motors Dl and D2 with a three-layer amplifier (AMP) force. As a result, the outer rotor members 21, 21 of the direct drive motors Dl, D1 rotate independently to move the arms Al, A2 (Fig. 29). Outer rotor member 21, 21 'rotates Then, resolver signals are output from the resolver stators 35, 36, 35 'and 36' that have detected the rotation angle as described above. Determines whether or not the outer rotor member 21, 21 'has reached the command position. 21 'Stop rotation. Thus, servo control of the outer rotor members 21 and 21 ′ becomes possible.

[0194] When driving multiple axes in a vacuum environment, if the current rotation position of the arms A1 and A2 is not recognized when the power is turned on, the arm A1 etc. is hit against the wall of the vacuum chamber or the shatter of the vacuum chamber. In this embodiment, the absolute resolver stators 36 and 36 'that detect the absolute position of one rotation of the rotating shaft and the incremental resolver stators 35 and 35' that detect the rotational position with finer resolution are used in this embodiment. Since the variable reluctance resolver is used, the rotational position control of the outer rotor members 21 and 21, that is, the arms Al and A2, can be performed with high accuracy.

[0195] Here, since a force detector that employs a resolver for detecting the rotation of the inner rotor 30 can be arranged on the atmosphere side inside the partition wall 13, in general, a servo motor used for high-precision positioning is highly accurate and smooth. An optical encoder adopted as a position detecting means for driving, a magnetic encoder using a magnetoresistive element, or the like can also be used. FIG. 33 is a cross-sectional view similar to FIG. 30 that is helpful for the second embodiment. With respect to the present embodiment, different parts from those of the embodiments of FIGS. 30 to 32 will be described, and parts having similar functions will be denoted by the same reference numerals and description thereof will be omitted.

[0196] In the present embodiment, the annular portion 113a is airtightly bolted to the step portion 11Oa of the upper disc portion 110 attached to the upper surface of the cylindrical main body 112 via an O-ring OR. ing. The lower portion of the annular portion 113a is a thin flange portion 113c extending radially outward, and the upper end of the thin cylindrical portion 113b is TIG welded to the bent outer edge. The thickness of the attachment portion of the annular portion 113a is thicker than the thickness of the flange portion 113c and the thin cylindrical portion 113b. The lower end of the thin cylindrical portion 113b is TIG welded to the holder 15 in the same manner as in the above-described embodiment. The annular portion 113a, the flange portion 113c, the thin cylindrical portion 113b, and the holder 15 constitute a partition wall 113. In addition, the disc 110, the main body 112, and the disc 10 are used for nosing. Constitute.

In the present embodiment, the upper surface of the upper disk part 110 is closed by the lid member 101, and the bearing holder 107 attached to the outer periphery thereof supports the bearing 19 ′. Therefore, the cylindrical member 123 of the direct drive motor D1 does not extend to the direct drive motor D2 side. The upper disk part 110, the lid member 101, and the bearing holder 107 have high corrosion resistance and are made of austenitic stainless steel.

The outer diameter portion 110a of the mounting seat surface of the bearing holder 107 in the upper disc portion 110 is located radially inward from the thin cylindrical portion 113b. Therefore, if the bearing holder 107 is removed from the upper disc portion 110, 2 The two outer rotor members 21 and 21 ′ can be removed upward without disassembling the upper disk portion 110. Therefore, it is possible to facilitate work that does not require disassembly of the airtight structure during maintenance. That is, the maximum outer diameter portion of the housing (main body 12 and upper disc portion 110) supporting the partition wall structure is the outer rotor of the direct drive motors D1 and D2 (the outer rotor members 21 and 21 ′ and the ring-shaped member 23). And 23)), the outer rotor of the direct drive motors D1 and D2 can be removed from the bulkhead 13 by removing the bearing holder 107 from the housing, which facilitates inspection and removal. , Maintenance is also improved. Furthermore, since only the bearing holder 107 need be removed, there is no need to check for leaks when reassembling without the need to remove the bulkhead structure, and assemblability is improved.

[0198] Furthermore, in the present embodiment, the thickness of the flange portion 113c is thinner than the thickness of the annular portion 113a of the partition wall 113. Therefore, due to dimensional accuracy, mechanical accuracy, and temperature change, Even when the axial expansion and contraction stress is generated in the partition wall 113, the thin flange portion 113c is deformed, so that the axial stress and bending stress of the partition wall 113 can be relieved. Can be prevented. In addition, since it is not necessary to process the annular portion 113a and the upper disk portion 110 and the main body 12 to which the annular portion 113a is attached with high accuracy, a lower cost direct drive motor can be provided.

[0199] In the above embodiment, the force described using the example using the surface magnet type 32-pole 36-slot outer rotor type brushless motor is not limited to this type of motor. Applicable, other magnetic pole types, eg permanent magnets It may be an embedded type, another slot combination, or an inner rotor type.

Further, as a countermeasure against interference of each axis, a configuration may be adopted in which the number of rotor poles and the number of slots of adjacent axes in the axial direction are different. For example, in the case of 2-axis coaxial, the first axis is 32 poles and 36 slots, the second axis is 24 poles and 27 slots, and in the case of 4-axis coaxial, the first axis and the third axis are 32 poles and 3 6 slots. If the two axes and the fourth axis are configured with 24 poles and 27 slots, mutual interference such as generation of thrust in the rotational direction to the rotor and magnetic coupling device due to the magnetic field of each axis can be prevented.

[0200] The rotor permanent magnet is a neodymium (Nd-Fe-B) -based magnet, and nickel coating is used as an example of coating to improve corrosion resistance. This material is not limited to the surface treatment, but is changed as appropriate depending on the environment in which it is used. For example, samarium-cobalt (Sm'Co) is less susceptible to high-temperature demagnetization depending on the temperature conditions during beta-out. System magnets should be used, and if used in ultra-vacuum, a titanium nitride coating with a high outgas barrier should be applied.

[0201] Also, the yoke is made of low-carbon steel and explained with an example of nickel plating. This material is not limited to the surface treatment, and is appropriately changed depending on the environment used. Especially for surface treatment, if it is used in ultra-vacuum, it should be applied with force with few pinholes such as Zen plating, clean soldering, and titanium nitride coating.

[0202] In addition, bearings 19 and 19 'have been described using an example of grease lubricated four-point contact ball bearings for vacuum. It can be changed as appropriate depending on conditions, rotational speed, etc., and it can be a cross roller bearing. In the case of a 4-axis coaxial motor, it can be supported by another bearing to further increase mechanical rigidity. If a multi-point contact bearing cannot be used, such as when rotating at high speeds, a bearing that supports the rotor of each axis and another bearing is a deep groove ball bearing. It may be a structure that applies preload as a receiver, and when used in ultra-vacuum, use a metal-lubricated one that does not release gas, such as plating a soft metal such as gold or silver on the race. May be.

[0203] In addition, the inner rotor functioning as a magnetic coupling has been described as using a permanent magnet and a back yoke. However, the material and shape of the permanent magnet and the back yoke are not limited thereto. For example, depending on the mass of the resolver and the frictional torque of the bearing, the number of poles may not be the same as that of the rotor, or may not be the same. A salient pole that does not use a permanent magnet may be used. Further, although an example in which a resolver is used as an angle detector has been described, it can be appropriately changed depending on manufacturing cost and resolution, and for example, an optical rotary encoder may be used.

[0204] In addition, an example in which grease lubrication four-point contact ball bearings are used as the bearings 33 and 33 'that rotatably support the rotation side of the angle detector has been described, but this type and the lubrication method are limited. However, if the multi-point contact bearing cannot be used, such as high-speed rotation or reduction of friction torque, an anguilla bearing is a deep groove ball bearing. A structure may be used in which two are arranged for each axis to apply preload.

[0205] Although the present invention has been described above with reference to the embodiments, it should be understood that the present invention should not be construed as being limited to the above-described embodiments but may be modified or improved as appropriate. The For example, the motor system of the present embodiment can be used not only in a vacuum atmosphere but also in an atmosphere outside the atmosphere. For example, in the case of a semiconductor manufacturing process, the reactive gas for etching may be introduced into the vacuum chamber after evacuation. In the motor system of this embodiment, the inside and the outside are shielded by the partition walls. Also, there is no risk of the motor coil or insulation material being etched.

[Fifth embodiment]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 34 is a perspective view of a frog redder arm type transport device using a direct drive motor that works in this embodiment. is there. In FIG. 34, four direct drive motors Dl, D2, D3, and D4 are connected in series. The first arm A1 is connected to the rotor of the lowermost direct drive motor D1, and the first link L1 is pivotally connected to the tip of the first arm A1. On the other hand, the second arm A2 is connected to the rotor of the direct drive motor D2 thereon, and the second link L2 is pivotally connected to the tip of the second arm A2. Further, a first arm A1 is connected to the rotor of the upper direct drive motor D3, and a first link L1 'is pivotally connected to the tip of the first arm A1. Further, the second arm A2 is connected to the rotor of the uppermost direct drive motor D4, and the second link L2 ′ is pivotally connected to the tip of the second arm A2. The links LI and L2 are pivotally connected to the table T on which the wafer W is placed, and the links Ll 'and L2' are pivoted to the table T 'on which another wafer W is placed. It is linked movably.

[0206] The force apparent from Fig. 34 If the rotors of the direct drive motors Dl and D2 rotate in the same direction, the table T also rotates in the same direction, and if the powerful rotor rotates in the opposite direction, the table T becomes The direct drive motors Dl and D2 are approaching or separating from each other. Therefore, if the direct drive motors Dl and D2 are rotated at an arbitrary angle, the wafer W can be transferred to an arbitrary two-dimensional position within a range where the table T can reach. On the other hand, if the rotors of the direct drive motors D3 and D4 rotate in the same direction, the table T 'also rotates in the same direction, and if the powerful rotor rotates in the opposite direction, the table T' becomes a direct drive motor. It approaches or separates from D3 and D4. Therefore, if the direct drive motors D3 and D4 are rotated at an arbitrary angle, the wafer W can be transferred to an arbitrary two-dimensional position within the range where the table T ′ can reach.

[0207] As described above, for example, in a wafer transfer arm arranged in a vacuum chamber in a semiconductor manufacturing apparatus, for example, an apparatus having a plurality of arms such as a scalar type or a frog redder type shown in the drawing, a plurality of rotations are particularly required. A motor is required. In a vacuum environment, the surface area of contact with the outside world should be minimized, and at the same time, the number of mounting holes for motors, etc., should be minimized to make effective use of space. Also, in order to transport the wafer W horizontally and with minimal vibration, it is necessary to hold the moment acting on the tip of the arm firmly at the rotor support. Therefore, several direct drive motors Dl, D2, D3, D4 Connected coaxially at the jing part, and the connection part is tightly joined with a seal (tightly joined by welding, o-ring, metal gasket, etc.) to separate the space where the motor rotor is located from the space outside the housing It is also necessary.

[0208] In addition, in order to transport wafer W horizontally and with less vibration, the moment acting on the tips of arms Al, A2, Al ', A2' must be held firmly by the rotor support. . In addition, when driving multiple axes in a vacuum environment, if the current arm rotation position is not recognized when the power is turned on, the arm Al, A2, Al There is a possibility of hitting ', A2', etc. A motor system in which direct drive motors that can meet such demands are coaxially connected will be described.

In this embodiment, a surface magnet type 32-pole 36-slot outer rotor brushless type direct drive motor is used. The slot combination of 32 poles and 36 slots is generally known to have a large magnetic attraction force in the radial direction and large vibration during rotation. is there . 2 ⁿ times (n is an integer) cancels out the magnetic attractive force in the radial direction. Therefore, vibration during rotation can be achieved without increasing the roundness and coaxiality of the stator and rotor and the rigidity of the mechanical parts. Can be made small and cogging is inherently small, so that a very smooth rotation can be obtained. On the other hand, by using such a very multi-pole motor, the electrical angle cycle is greater than the mechanical angle cycle, so positioning controllability is good. Therefore, it is suitable for a direct drive motor that drives a robot apparatus without using a speed reducer as in the present invention. In addition, since the thickness and salient pole width of the stator connecting portion and the yoke thickness of the rotor can be reduced without lowering the total magnetic flux, the direct drive motor having a thin and large diameter and narrow width as in the present invention is used. Is preferred.

[0210] FIG. 35 is a diagram of the configuration of FIG. 34 cut along the Π-Π line and viewed in the direction of the arrow. The internal structure of the 4-axis motor system will be described in detail with reference to FIG. First, the direct drive motor D1 will be described. The hollow cylindrical first main bodies 12 are fixed to each other by bolts 11 fitted into the central opening 10a of the disc 10 installed on the surface plate G. The first body 12 has a reduced diameter portion 12h on the outer periphery of its upper end. The second main body 112 having a shape similar to that of the first main body 12 has a large-diameter portion 112h on the inner periphery of the lower end thereof. Reduced diameter section 12h, large The first main body 12 and the second main body 112 are coaxially connected by being fitted to the diameter portion 112h. The center of the main bodies 12 and 112 can be used to pass wiring to the stator. The first main body 12, the disk 10 and the second main body 112 constitute a housing.

[0211] On the upper surface of the second main body 112, a disc member 110 whose center opening is closed by the lid member 101 is attached. The disc member 110 is bolted to the lower surface of the upper end of the partition wall 13 and has a bearing holder 107 attached to the outer periphery. The disc member 110, the lid member 101, and the bearing holder 107 are made of austenitic stainless steel having high corrosion resistance. The bearing holder 107 will be described later.

The partition wall 13 is made of stainless steel, which is a non-magnetic material, and passes through the direct-drive motors D4, D3, D2, and D1 in the axial direction from the periphery of the thick disk portion 13a attached to the disk member 110. And a thin cylindrical portion 13b extending. A flange 13c extending from the lower surface of the disk portion 13a is TIG welded to the upper end of the cylindrical portion 13b. That is, the partition wall 13 is commonly used for the direct drive motors D1 to D4.

[0212] The lower end of the cylindrical portion 13b is joined to the holder 15 so as to be sealed by TIG welding, and the holder 15 is fixed to the disc 10 with bolts 16. Here, by setting the welded portion of the cylindrical portion 13b to substantially the same thickness, it is possible to prevent heat from escaping only to the component on one side and to weld the fitting portion uniformly. The contact surface between the holder 15 and the disk 10 is provided with a groove force to fit the seal member. After the seal member OR is fitted into the groove, the holder 15 and the disk 10 are fastened by the bolt 16. , Atmospheric side force is also separated from the fastening part. The partition wall 13 is made of austenitic stainless steel SUS316, which has high corrosion resistance and is particularly low in magnetism. The holder 15 is also made of SUS316 because of its weldability with the partition wall 13.

[0213] Further, the disk member 110 and the partition wall 13, and the partition wall 13 and the holder 15 are hermetically joined, and the holder 15 and the disk 10 and the disk 10 and the surface plate G are respectively O- Airtight by ring OR. Therefore, the external force of the internal space surrounded by the disk 10, the disk member 110, and the partition wall 13 is also airtight. The partition wall 13 is not necessarily made of a nonmagnetic material. Further, instead of using an O-ring OR to seal the air, the members may be sealed by electron beam welding or laser beam welding.

[0214] On the upper surface of the outer periphery of the disc 10, a bearing holder 17 is formed in a body-like manner. Bearing ho The outer ring of a four-point contact ball bearing 19 used in a vacuum is fitted to the rudder 17 in a fitting manner and fixed with bolts 20. On the other hand, the inner ring of the bearing 19 is fixed to a double cylindrical cylindrical member 23 including the first outer rotor member 21 and is fixed by a bolt 22 that fastens the first outer rotor member 21 together. Yes. That is, the first outer rotor member 21 is rotatably supported with respect to the partition wall 13 by the cylindrical member 23 that supports the arm A1 (FIG. 34).

The first outer rotor member 21 and the cylindrical member 23 constitute an outer rotor.

[0215] The disc 10 and the bearing holder 17 are made of austenitic stainless steel having high corrosion resistance. The disc 10 also serves as a fitting and fixing device with the surface plate G that is a chamber, and has a lower surface. A groove 10b is provided to fill the O-ring OR.

Bearing 19 is a four-point contact ball bearing that can apply radial, axial, and moment loads with a single bearing. By using this type of bearing, the direct drive motor D1 requires only one bearing, so the four-axis coaxial motor system of the present invention can be made thinner. The bearing 19 is made of martensite stainless steel, which has high corrosion resistance for both the inner and outer rings and can be hardened by quenching. The rolling elements are ceramic balls, and the lubricant is vacuum grease that does not solidify even under vacuum.

[0216] The bearing 19 may be made of metal lubricated by plating a soft metal such as gold or silver on the inner ring and the outer ring so as not to release outgas even in vacuum, or a four-point contact ball. Since it is a bearing, the force that can receive the moment in the direction in which the first outer rotor member 21 tilts from the arm A1 is not limited to a four-point contact type, and cross roller, cross ball, and cross taper bearings can also be used. It can be used in a preloaded state, or fluorine film treatment (DFO) can be performed to improve lubricity.

[0217] The first outer rotor member 21 includes a permanent magnet 21a, an annular yoke 21b made of a magnetic material to form a magnetic path, and a non-magnetic material for mechanically fastening the permanent magnet 21a and the yoke 21b. It is made up of a wedge (not shown) that also has power. Permanent magnet 21a is a segment type divided into poles, each of which has a sector shape, consisting of 16 magnetic poles each consisting of 16 poles with N poles and S poles. . The inner and outer diameter arc centers are the same, but by setting the tangent intersection of the circumferential end face closer to the permanent magnet 21a, the wedge is moved to the outer diameter of the yoke 21b. The permanent magnet 21a is fastened to the yoke 21b by screwing up from the side. With this configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. Permanent magnet 21a is a high energy product, neodymium (Nd-Fe-B) based magnet, which is nickel coated to enhance corrosion resistance. The yoke 21b is made of low-carbon steel with high magnetism, and is nickel-plated to improve wear resistance and corrosion resistance after processing and molding, and to prevent wear during bearing replacement.

[0218] On the radially inner side of the partition wall 13, the first stator 29 is arranged so as to face the inner peripheral surface of the first outer rotor member 21. The first stator 29 is attached to a cylindrically deformed lower portion of a flange portion 12a extending in the radial direction at the center of the main body 12, and is formed of a laminated material of electromagnetic steel plates. After the bobbin is fitted, the motor coil is concentrated. The outer diameter of the first stator 29 is approximately the same as or smaller than the inner diameter of the partition wall 13.

[0219] A first inner rotor 30 is disposed adjacent to and parallel to the first stator 29. The first inner rotor 30 is rotatably supported by ball bearings 33 with respect to a resolver holder 32 bolted to the outer peripheral surface of the main body 12. A permanent magnet 30a is attached to the outer peripheral surface of the first inner rotor 30 via a knock 30b. As with the permanent magnet 21a of the first outer opening member 21, the permanent magnet 30a has a 32-pole configuration, and each of the 16 N-pole and S-pole magnets alternately has a magnetic metal force. Accordingly, the first inner rotor 30 is rotated in synchronism with the first outer rotor member 21 driven by the first stator 29.

[0220] The bearing 33 that rotatably supports the first inner rotor 30 is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, it is possible to reduce the thickness of the direct drive motor D1 because only one bearing is required. Since the interior of the partition wall 13 is an atmospheric environment, a bearing using grease lubrication based on general bearing steel and mineral oil can be applied.

Since the inside of the partition wall 13 is an atmospheric environment, the permanent magnet 30a is bonded and fixed to the back yoke 30b. Permanent magnet 30a is a high energy product neodymium (Nd-Fe-B) magnet with nickel coating to prevent demagnetization due to defects. Yoke 30b is made of low-carbon steel with high magnetic properties, and is chromated to prevent fouling after machining. is doing.

[0221] The resolver rotors 34a and 34b are assembled as detectors for measuring the rotation angle on the inner periphery of the first inner rotor 30, and the resolver stator 35 is disposed on the outer periphery of the resolver holder 32 so as to face it. In this embodiment, the high-resolution incremental resolver stator 35 and the absolute resolver stator 36 that can detect the position of the rotor in one rotation are arranged in two layers. /! For this reason, even when the power is turned on, the rotational angle of the absolute resolver rotor 34b is known, no return to origin is required, and the electrical phase angle of the magnet with respect to the coil increases, so the drive current of the direct drive motor D1 The rotation angle used for control can be detected without using a pole detection sensor.

[0222] The resolver holder 32 and the first inner rotor 30 are made of carbon steel, which is a magnetic material, so that electromagnetic noise from the motor field and motor coil is not transmitted to the resolver stators 35, 36 that are angle detectors. In order to prevent fouling after processing and molding, it is chromated.

The high-resolution variable reluctance resolver used in the present embodiment has an incremental resolver rotor 34a having a plurality of slot teeth having a constant pitch, and the outer peripheral surface of the incremental resolver stator 35. Are provided with teeth shifted in phase with respect to the incremental resolver rotor 34a at each magnetic pole parallel to the rotation axis, and a coil is wound around each magnetic pole. When the incremental resolver rotor 34a rotates together with the first inner rotor 30, the reluctance between the incremental resolver stator 35 and the magnetic pole changes, and the fundamental wave component of the change in reluctance becomes n cycles in one revolution of the incremental resolver rotor 34a. Thus, the change in reluctance is detected, digitized by the resolver control circuit shown in FIG. 36, and used as a position signal, so that the rotational angle of the incremental resolver rotor 34a, that is, the first inner rotor 30 is (Or rotation speed) is detected. The resolver rotors 34a and 34b and the resolver stators 35 and 36 constitute a detector.

[0223] According to this embodiment, the first outer rotor member 21 rotates at the same speed, that is, rotates with the first outer rotor member 21 by the magnetic coupling action. The rotation angle of 21 can be detected through the partition wall 13. Further, in the present embodiment, the resolver alone has the bearing 33 without using the parts forming the motor, and therefore, the eccentricity adjustment with the resolver alone is performed before the resolver coil is assembled into the housing. Since accuracy adjustment such as position adjustment can be performed, there is no need to provide adjustment holes or notches on both flanges of the housing.

Next, the force for explaining the direct drive motor D2 Here, the first main body 12 constitutes housing. The cylindrical member 23 of the direct drive motor D1 described above extends upward to a position where it overlaps with the direct drive motor D2, and the four-point contact ball bearing used in the vacuum on the inner peripheral surface 19 The outer ring of 'is fitted in and fitted with bolts 20'. On the other hand, the inner ring of the bearing 19 'is fixed by a bolt 22' that fits around the circumferential surface of a double cylindrical ring-shaped member 23 'and fastens the second outer rotor member 21' together. That is, the second outer rotor member 21 ′ is rotatably supported with respect to the partition wall 13 by the ring-shaped member 23 ′ that supports the arm A2 (FIG. 34). The second outer rotor member 21 ′ and the ring-shaped member 23 ′ constitute an outer rotor.

[0225] Bearing 19 'is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, the direct drive motor D2 requires only one bearing, so the four-axis coaxial motor of the present invention can be made thinner. The inner and outer rings are made of martensitic stainless steel, which has high corrosion resistance and can be hardened by quenching. The rolling elements are ceramic balls, and the lubricant is vacuum grease that does not solidify even under vacuum.

The bearing 19 'may be made of a metal lubrication that is plated with a soft metal such as gold or silver on the inner ring and the outer ring and does not release outgas even in vacuum, or a four-point contact ball bearing. Therefore, the force that can receive the moment in the tilting direction of the second outer rotor member 21 from the arm A1 is not limited to the four-point contact type, and cross rollers, cross balls, and cross taper bearings can also be used. It can be used in the state, or fluorine coating (DFO) can be applied to improve lubricity.

[0226] Further, the ring-shaped member 23 'has a surface for fitting and fixing the inner ring of the bearing 19'. Four-point contact ball bearing 19 'is a very thin bearing, and the accuracy and linear expansion of the assembled parts Rotational accuracy and friction torque are greatly affected by the number difference. Therefore, in the case of the present embodiment, the inner ring of the bearing 19 ′, which is a rotating ring, is tightly fitted or intermediately fitted to a ring-shaped member 23 ′, which is easy to obtain machining accuracy and whose linear expansion coefficient is substantially the same as the bearing ring material of the bearing. By fitting the outer ring of the bearing 19 ', which is a fixed ring, with a clearance fit on the inner periphery of the cylindrical member 23, it is possible to prevent a decrease in rotational accuracy of the bearing 19' and an increase in friction torque due to a temperature rise. It is.

[0227] The second outer rotor member 21 'mechanically fastens the permanent magnet 21a', the annular yoke 21b 'made of a magnetic material to form a magnetic path, and the permanent magnet 21a' and the yoke 21b '. It is made up of a wedge (not shown) that also has non-magnetic strength. Permanent magnet 21a 'is a segment type with a configuration of 32 poles, each consisting of 16 magnets of N poles and S poles alternately made of magnetic metal, and each pole is segmented. Although the inner and outer diameter arc centers are the same, the tangential intersection of the circumferential end face is closer to the permanent magnet 21a ', so that the wedge is tightened with a screw from the outer side of the yoke 2 lb' permanent magnet 21a 'Is fastened to York 21b. With such a configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. The permanent magnet 21a 'is a neodymium (Nd-Fe-B) magnet with a high energy product, and has a nickel coating to improve corrosion resistance. Yoke 21b 'is made of low-carbon steel with high magnetism and is plated with nickel to improve wear resistance and corrosion resistance after machining and to prevent wear during bearing replacement.

[0228] On the radially inner side of the partition wall 13, the second stator 29 'is disposed so as to face the inner peripheral surface of the second outer rotor member 21'. The second stator 29 ′ is attached to a cylindrically deformed upper portion of the flange portion 12 a extending in the radial direction at the center of the first main body 12, and is formed of a laminated material of electromagnetic steel plates, and is attached to each salient pole. In this case, the motor coil is concentrated after the bobbin is fitted as an insulation treatment. The outer diameter of the second stator 29 is substantially the same as or smaller than the inner diameter of the partition wall 13.

[0229] A second inner rotor 30 'is disposed radially inward of the second stator 29'. The second inner rotor 30 ′ is rotatably supported by a ball bearing 33 ′ with respect to a resolver holder 32 ′ bolted to the outer peripheral surface of the first main body 12. On the outer peripheral surface of the second inner rotor 30 ' The permanent magnet 30a ′ is attached via the back yoke 30b ′. The permanent magnet 30a ′ has a configuration of 32 poles, as in the case of the permanent magnet 21a ′ of the second outer rotor member 21 ′, and is composed of 16 N-pole and 16 S-pole magnets alternately made of magnetic metal. Accordingly, the second inner rotor 30 ′ is rotationally driven by the second stator 29 ′ in synchronization with the second outer rotor member 21 ′.

[0230] The bearing 33 'that rotatably supports the second inner rotor 30' is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, only one bearing is required, so the direct drive motor D2 can be made thinner. Since the inside of the partition wall 13 is an atmospheric environment, a bearing using grease lubrication based on general bearing steel and mineral oil can be applied.

[0231] A resolver rotor 34b 'is assembled on the inner periphery of the second inner rotor 30' as a detector for measuring the rotation angle. The resolver stator 32 'is arranged on the outer periphery of the resolver holder 32' so as to face it. In this embodiment, a high-resolution incremental resolver stator 35, and an absolute resolver stator 36 'that can detect the position of the rotor in one rotation are divided into two. Arranged in layers. For this reason, even when the power is turned on, the rotational angle of the absolute resolver rotor 34 'is known, no return to origin is required, and the electrical phase angle of the magnet with respect to the coil increases, so the relative position of the direct drive motor D2 Rotation angle is possible without using a pole detection sensor! /

[0232] The resolver holder 32 'and the second inner rotor 30' are magnetic bodies so that electromagnetic noise from the motor field and the motor coil is not transmitted to the resolver stators 35 'and 36' that are angle detectors. Carbon steel is used as a material, and chromate plating is applied after processing to prevent fouling.

According to the present embodiment, the magnetic coupling action is applied to the second outer rotor member 21 ′. As a result, the second inner rotor 30 ′ rotates at the same speed, that is, rotates around, so that the rotation angle of the second outer rotor member 21 ′ can be detected through the partition wall 13. Further, in the present embodiment, the resolver itself has the bearing 33 ′ without using the parts forming the motor, and therefore, the eccentricity adjustment with the resolver alone is not performed before the housing is assembled. The housing can be adjusted for accuracy, such as adjusting the position of the housing, so there is no need to provide additional adjustment holes or notches on both flanges.

In the high resolution variable reluctance resolver used in the present embodiment, the incremental resolver rotor 34a ′ has a plurality of slot tooth rows having a constant pitch, and the outer circumference of the incremental resolver stator 35. The surface is provided with teeth that are shifted in phase with respect to the incremental resolver rotor 34a ′ at each magnetic pole parallel to the rotation axis, and a coil is wound around each magnetic pole. When the incremental resolver rotor 34a rotates together with the first inner rotor 30, the reluctance between the magnetic poles of the incremental resolver stator 35 changes, and the fundamental wave component of the change in reluctance with one revolution of the incremental resolver rotor 34a. 36, the reluctance change is detected, digitalized by the resolver control circuit shown in FIG. 36, and used as a position signal, so that the incremental resolver rotor 34a ′, that is, the first inner The rotation angle (or rotation speed) of the rotor 30 is detected. The resolver rotors 34a, 34b and the resolver stators 35, 36 constitute a detector.

[0234] The first stator 29 and the second stator 29 'are arranged vertically with the flange portion 12a as the center, and the resolver is arranged radially inward. The first body 12 has a hollow structure, and the flange portion 12a has at least one radial through hole 12d communicating with the center through which the motor wiring is routed. The structure is drawn out to the center of On the other hand, at least one notch 12e, 12e is provided at each end of the first main body 12, and the resolver wiring is drawn out to the center of the first main body 12 through these notches. With this structure, the housing side force can also be arranged in the order of the resolver of the direct motor D1, the stator 29, the stator 29 of the direct motor D2, and the resolver in this order. In addition, the angle of the stator and resolver can be adjusted. So, if you prepare a separate equipment to drive the outer rotor as a reference, By setting the first main body 12 incorporating the stator and resolver into the equipment, the angle of the resolver relative to the stator can be adjusted with high accuracy, preventing a decrease in angular positioning accuracy due to misalignment, and The compatibility of the drive control circuit with the four-axis coaxial motor of the invention can be enhanced.

FIG. 37 is a block diagram showing drive circuits for the direct drive motors Dl and D2. When a motor rotation command is also input to the external computer force, the motor control circuit DMC1 for the direct drive motor D1 and the motor control circuit DMC2 for the direct drive motor D2 are each sent from the CPU to the three-layer amplifier (AMP). The drive signal is output, and the drive current is supplied to the direct drive motors Dl and D2 with a three-layer amplifier (AMP) force. As a result, the outer rotor members 21 and 21 of the direct drive motors Dl and D1 rotate independently to move the arms Al and A2 (Fig. 34). When the outer rotor members 21, 21 ′ rotate, resolver signals are output from the resolver stators 35, 36, 35 ′, 36 ′ that have detected the rotation angles as described above. The CPU input after digital conversion by RDC) determines whether or not the outer rotor members 21, 21 'have reached the command position.If the CPU reaches the command position, it sends a drive signal to the 3-layer amplifier (AMP). Stopping stops the rotation of the outer rotor members 21, 21 '. Thus, servo control of the outer rotor members 21 and 21 ′ becomes possible.

[0236] When driving multiple axes in a vacuum environment, if the current rotation position of the arms A1 and A2 is not recognized when the power is turned on, the arm A1 etc. will be hit against the wall of the vacuum chamber or the shatter of the vacuum chamber. In this embodiment, the absolute resolver stators 36 and 36 'that detect the absolute position of one rotation of the rotating shaft and the incremental resolver stators 35 and 35' that detect the rotational position with finer resolution are used in this embodiment. Since the variable reluctance resolver is used, the rotational position control of the outer rotor members 21 and 21, that is, the arms Al and A2, can be performed with high accuracy.

[0237] Here, since a force detector that employs a resolver for detecting the rotation of the inner rotor 30 can be arranged on the atmosphere side inside the partition wall 13, in general, a servo motor used for high-accuracy positioning is highly accurate and smooth. An optical encoder adopted as a position detecting means for driving, a magnetic encoder using a magnetoresistive element, or the like can also be used. Next, the direct drive motor D4 will be described. A bearing holder 107 detachably bolted to the disc member 110 attached to the second main body 112 is fitted with an outer ring of a four-point contact ball bearing 119 used in a vacuum. It is attached and fixed with bolts 120. On the other hand, the inner ring of the bearing 119 is fixed by a bolt 122 that is fitted into a double cylindrical cylindrical member 123 including the first outer rotor member 121 and is fastened together with the first outer rotor member 121. . That is, the first outer rotor member 121 is rotatably supported with respect to the partition wall 113 by the cylindrical member 123 that supports the arm A2 ′ (FIG. 34). The first outer rotor member 121 and the cylindrical member 123 constitute an outer rotor.

[0238] The bearing holder 107 has high corrosion resistance and is made of austenitic stainless steel. Bearing 119 is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, only one bearing of the direct drive motor D4 is required, so the four-axis coaxial motor system of the present invention can be made thinner. Bearing 119 is made of martensitic stainless steel, which has high corrosion resistance for both the inner and outer rings and can be hardened by quenching. The rolling elements are ceramic balls, and the lubricant is vacuum grease that does not solidify even under vacuum.

[0239] Incidentally, the bearing 119 may be made of a metal lubricated material in which a soft metal such as gold or silver is plated on the inner ring and the outer ring and no outgassing is released even in a vacuum, or a four-point contact ball. Because it is a bearing, the force that can receive the moment in the tilting direction of the arm A2 and the first outer rotor member 121 is not limited to the four-point contact type, and cross rollers, cross balls, and cross taper bearings can also be used. It can be used in a preloaded state, or it can be treated with fluorine film (DFO) to improve lubricity.

[0240] The first outer rotor member 121 includes a permanent magnet 121a, an annular yoke 121b made of a magnetic material to form a magnetic path, and a nonmagnetic material for mechanically fastening the permanent magnet 121a and the yoke 121b. It is composed of a wedge (not shown) that also has physical strength. The permanent magnet 121a is a segment type in which each of the 16 pole magnets is composed of 16 magnetic poles each having 32 poles and is alternately divided into magnetic poles, each of which has a sector shape. The center of the arc of the inner and outer diameters is the same, but the wedge is reduced by making the tangent intersection of the circumferential end face closer to the permanent magnet 121a. The permanent magnet 121a is fastened to the yoke 121b by tightening with a screw from the outer diameter side of the yoke 121b. With such a configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. The permanent magnet 121a is a neodymium (Nd—Fe-B) magnet with a high energy product, and is nickel-coated to enhance corrosion resistance. The yoke 12 lb is made of low-carbon steel with high magnetic properties, and is plated with nickel to improve wear resistance and corrosion resistance after machining and to prevent wear during bearing replacement.

[0241] On the radially inner side of the partition wall 113, the first stator 129 is disposed so as to face the inner peripheral surface of the first outer rotor member 121. The first stator 129 is attached to a cylindrically deformed lower portion of a flange portion 112a extending in the radial direction at the center of the main body 112. The first stator 129 is formed of a laminated material of electromagnetic steel plates, and each salient pole is insulated. After the bobbin is fitted, the motor coil is concentrated. The outer diameter of the first stator 129 is substantially the same as or smaller than the inner diameter of the partition wall 13.

[0242] A first inner rotor 130 is disposed adjacent to and parallel to the first stator 129. The first inner rotor 130 is rotatably supported by ball bearings 133 with respect to a resolver holder 132 that is bolted to the outer peripheral surface of the second main body 112. A permanent magnet 130a is attached to the outer peripheral surface of the first inner rotor 130 via a knock yoke 130b. The permanent magnet 130a has a configuration of 32 poles as in the case of the permanent magnet 121a of the first outer rotor member 121, and 16 magnets of N poles and S poles alternately have a magnetic metal force. Accordingly, the first inner rotor 130 is rotated along with the first outer rotor member 121 driven by the first stator 129.

[0243] The bearing 133 that rotatably supports the first inner rotor 130 is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, only one bearing is required, so the direct drive motor D4 can be made thinner. Since the inside of the partition wall 13 is an atmospheric environment, a bearing using grease lubrication based on general bearing steel and mineral oil can be applied.

Since the inside of the partition wall 13 is an atmospheric environment, the permanent magnet 130a is bonded and fixed to the back yoke 130b. Permanent magnet 130a is a high energy product neodymium (Nd-Fe-B) magnet It has a nickel coating to prevent demagnetization due to wrinkles. The yoke 130b is made of low-carbon steel with high magnetism, and is chromated to prevent fouling after machining.

[0244] Resolver rotors 134a and 134b are assembled as detectors for measuring the rotation angle on the inner circumference of the first inner rotor 130, and the resolver stator 135 is placed on the outer circumference of the resolver holder 132 so as to face it. In this embodiment, a high-resolution incremental resolver stator 135 and an absolute resolver stator 136 capable of detecting whether the rotor is in one rotation are arranged in two layers. Therefore, even when the power is turned on, the rotational angle of the absolute resolver rotor 134b is known, no return to origin is required, and the electrical phase angle of the magnet with respect to the coil increases, so the drive current of the direct drive motor D4 This is possible without using the rotation angle detection force pole sensor used for control.

[0245] The resolver holder 132 and the first inner rotor 130 are made of carbon steel, which is a magnetic body, so that electromagnetic noise from the motor field and the motor coil is not transmitted to the resolver stators 135 and 136 that are angle detectors. As a material, it is chromate-plated to prevent fouling after processing and molding.

The high-resolution variable reluctance resolver used in the present embodiment has an incremental resolver rotor 134a having a plurality of slot tooth rows having a constant pitch, and the outer peripheral surface of the incremental resolver stator 135. Are provided with teeth that are shifted in phase with respect to the incremental resolver rotor 134a at each magnetic pole in parallel with the rotation axis, and a coil is wound around each magnetic pole. When the incremental resolver aperture 134a rotates integrally with the first inner rotor 130, the reluctance with the magnetic pole of the incremental resolver stator 135 changes. The change in the reluctance is detected so that there are n cycles, and the change is detected and digitized by the resolver control circuit shown in FIG. 36, and used as a position signal. Rotation angle (or rotation speed) is detected. The detector is composed of the Resonore rotors 134a and 134b and the Resonore stators 135 and 136. [0246] According to the present embodiment, the first inner rotor 130 rotates at the same speed by the magnetic coupling action with respect to the first outer rotor member 121, that is, rotates with the first outer rotor member 121. The rotation angle can be detected through the partition wall 13. Also, in this embodiment, the parts forming the motor have the bearing 133 as a single resolver without using the nosing, so the eccentricity adjustment with the resolver alone can be performed before the resolver is assembled. Since accuracy adjustment such as position adjustment can be performed, it is not necessary to provide a separate adjustment hole or notch on both flanges of the housing.

[0247] Next, the force for explaining the direct drive motor D3. Here, the second main body 112 constitutes the housing. The cylindrical member 123 of the direct drive motor D4 described above extends downward to a position where it is superimposed on the direct drive motor D3, and the inner peripheral surface of the four-point contact ball bearing 119 'used in vacuum is used. The outer ring is fitted and fixed by bolt 120 '. On the other hand, the inner ring of the bearing 119 ′ is fixed by a bolt 122 ′ that fits to the circumferential surface of the double cylindrical ring-shaped member 123 ′ and fastens the second outer rotor member 121 ′ together. That is, the second outer rotor member 121 ′ is rotatably supported with respect to the partition wall 13 by the ring-shaped member 123 ′ that supports the arm A 1 ′ (FIG. 34).

The second outer rotor member 121 ′ and the ring-shaped member 123 ′ constitute an outer rotor.

[0248] Bearing 119 'is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, only one bearing for the direct drive motor D3 is required, so the four-axis coaxial motor of the present invention can be made thinner. The inner and outer rings are made of martensitic stainless steel, which has high corrosion resistance and can be hardened by quenching. The rolling elements are ceramic balls, and the lubricant is vacuum grease that does not solidify even under vacuum.

Note that the bearing 119 'is a four-point contact ball bearing that can be made by using a metal lubrication that does not emit outgas even in a vacuum by plating a soft metal such as gold or silver on the inner and outer rings. Therefore, the force that can receive the moment in the tilting direction of the arm A1 and the second outer rotor member 121 ′ of force is not limited to the four-point contact type, and cross rollers, cross balls, and cross taper bearings can also be used. It can be used in a pre-loaded state, or fluorine-based film treatment (DFO) can be performed to improve lubricity. [0249] The second outer rotor member 121 'mechanically fastens the permanent magnet 121a', the annular yoke 121b 'made of a magnetic material to form a magnetic path, and the permanent magnet 121a' and the yoke 121b '. It is made up of a wedge (not shown) that also has a non-magnetic force. Permanent magnet 121a 'is a segment type with 32 poles and 16 N pole and S pole magnets, each of which is divided into magnetic poles, each of which has a sector shape. is there. The inner and outer diameter arc centers are the same, but the tangential intersection of the circumferential end face is closer to the permanent magnet 121a ', so that the wedge is tightened from the outer diameter side of the yoke 121b' with a screw. 121a 'is fastened to yoke 1 21b'. With this configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. Permanent magnet 121a 'is a neodymium (Nd-Fe-B) magnet with high energy accumulation, and has a nickel coating to enhance corrosion resistance. Yoke 121b 'is made of low-carbon steel with high magnetism, and is subjected to nickel plating to improve wear resistance and corrosion resistance and to prevent wear during bearing replacement after molding.

[0250] On the radially inner side of the partition wall 13, the second stator 129 'is arranged so as to face the inner peripheral surface of the second outer rotor member 121'. The second stator 129 ′ is attached to the cylindrically deformed upper portion of the flange portion 112 a extending in the radial direction at the center of the second main body 112, and is formed of a laminated material of electromagnetic steel plates. After the bobbin is fitted into the salient pole as an insulation treatment, the motor coil is concentrated. The outer diameter of the second stator 129 'is approximately the same as or smaller than the inner diameter of the partition wall 13! /

[0251] A second inner rotor 130 'is arranged on the radially inner side of the second stator 129'.

The second inner rotor 130 ′ is rotatably supported by a ball bearing 133 ′ with respect to a resolver holder 132 ′ bolted to the outer peripheral surface of the second main body 112. A permanent magnet 130a 'is attached to the outer peripheral surface of the second inner rotor 130' via a knock yoke 130b '! /. Permanent magnet 130a 'has a configuration of 32 poles as in the case of permanent magnet 121a' of second outer rotor member 121 ', and 16 magnets of N poles and S poles are alternately made of magnetic metal. Therefore, the second inner rotor 130 ′ is driven to rotate in synchronization with the second outer rotor member 121 ′ by the second stator 129 ′! / Speak.

[0252] The bearing 33 'that rotatably supports the second inner rotor 30' is a radial, axial, motor This is a four-point contact ball bearing that can load the load with a single bearing. By using this type of bearing, the direct drive motor D3 can be made thinner because only one bearing is required. Since the inside of the partition wall 13 is an atmospheric environment, it is possible to use a bearing using grease lubrication based on general bearing steel and mineral oil.

Since the inside of the partition wall 13 is an atmospheric environment, the permanent magnet 130a 'is fixedly bonded to the back yoke 130b'. The permanent magnet 130a is a neodymium (Nd-Fe-B) magnet with a high energy product and is coated with nickel to prevent demagnetization due to defects. Yoke 130b 'is made of low-carbon steel with high magnetism and is chromate-plated for protection after machining.

[0253] Resolver rotors 134a, 134b are assembled as detectors for measuring the rotation angle on the inner periphery of the second inner rotor 130 ', and are arranged on the outer periphery of the resolver holder 132 so as to face it. In this embodiment, the resolver stators 135 'and 136' are attached to a high-resolution incremental resolver stator 135, and an absolute resolver stator 136 'that can detect the position of the rotor in one rotation. Arranged in two layers. For this reason, even when the power is turned on, the rotation angle of the detection rotor 134 'is known, no return to origin is required, and the electrical phase angle of the magnet with respect to the coil increases, so the relative rotation angle of the direct drive motor D3 can be reduced. It becomes possible without using the pole detection sensor! /

[0254] The resolver holder 132 and the second inner rotor 130 are magnetic bodies so that electromagnetic noise generated by the motor field and motor coil force is not transmitted to the resolver stators 135 'and 136' that are angle detectors. Carbon steel is used as a material, and chromate plating is applied after processing to prevent fouling.

According to the present embodiment, the second inner rotor 130 ′ rotates at the same speed by the magnetic coupling action with respect to the second outer rotor member 121 ′. The rotation angle can be detected through the partition wall 13. Further, in this embodiment, the resolver alone has the bearing 133 ′ without using the parts forming the motor, and therefore the eccentricity adjustment of the resolver alone before the assembly into the housing is performed. Since accuracy adjustment such as position adjustment can be performed, there is no need to separately provide adjustment holes or notches on both flanges of the housing. In the high resolution variable reluctance resolver used in the present embodiment, the incremental resolver rotor 134a ′ has a plurality of slot teeth having a constant pitch, and the magnetic poles of the incremental resolver stator 135. On the outer peripheral surface, teeth that are shifted in phase with respect to the incremental resolver rotor 134a ′ at each magnetic pole in parallel with the rotation axis are provided, and a coil is wound around each magnetic pole. When the incremental resolver rotor 134a rotates integrally with the second inner rotor 130 ', the reluctance with the magnetic pole of the incremental resolver stator 135 changes, and the basic change in reluctance with one revolution of the incremental resolver rotor 134a. Incremental resolver rotor 134a, that is, the second inner side is detected by detecting the change in reluctance so that the wave component has n cycles, digitizing it by the resolver control circuit shown in FIG. 36 and using it as a position signal. The rotation angle (or rotation speed) of the rotor 130 'is detected. The resolver rotors 134a and 134b and the resolver stators 135 and 136 constitute a detector.

[0256] The first stator 129 and the second stator 129 'are arranged vertically with the flange portion 112a as the center, and the resolver is arranged radially inside. The second body 112 has a hollow structure, and the flange portion 112a has at least one radial through hole 112d communicating with the center, through which the motor wiring is connected to the second wire 112d. It is structured to be pulled out to the center of the main body 112. On the other hand, at least one notch 112e, 112e force is provided at both ends of the second main body 112, and the resolver wiring is drawn out to the center of the second main body 112 via these. By adopting such a structure, it is possible to arrange the force on the side and the oozing side force in order of the resolver of the direct motor D4, the stator 129, the stator 129 of the direct motor D3, and the resolver in this order. The angle between the stator and resolver can be adjusted easily. Therefore, if a separate facility for rotationally driving the reference outer rotor is prepared, the angle of the resolver with respect to the stator can be adjusted with high accuracy by setting the second body 112 incorporating the stator and resolver into the facility. Therefore, it is possible to prevent the angle positioning accuracy from being lowered due to the deviation of the com- mission, and to improve the compatibility of the drive control circuit with the four-axis coaxial motor of the present invention.

FIG. 37 is a block diagram showing a drive circuit for the direct drive motors Dl and D2. When a motor rotation command is input to the external computer force, the direct drive motor D3 Motor control circuit DMC1 and direct drive motor D4 Motor control circuit DMC2 outputs a drive signal from its CPU to the three-layer amplifier (AMP), and direct drive from the three-layer amplifier (AMP) Drive current is supplied to motors D3 and D4. As a result, the outer rotor members 121 and 121 of the direct drive motors D3 and D4 rotate independently to move the arms ΑΙ ′ and A2 ′ (FIG. 34). When the outer rotor member 121, 121 'rotates, the resolver signal is output from the resolver stator 135, 136, 135', 136 'whose rotation angle has been detected as described above. The CPU input after digital conversion at) determines whether or not the outer rotor member 121, 121 'has reached the command position, and if it reaches the command position, stops the drive signal to the 3-layer amplifier (AMP) As a result, the rotation of the outer rotor members 121 and 121 ′ is stopped. As a result, servo control of the outer rotor members 121 and 121 ′ becomes possible.

[0258] When driving multiple axes in a vacuum environment, if the current rotation positions of the arms A1 and A2 'are not recognized when the power is turned on, the arm A1' In this embodiment, the absolute resolver stators 136 and 136 that detect the absolute position of one rotation of the rotating shaft, and the incremental resolver stator that detects a rotational position with finer resolution are used in this embodiment. Since the variable reluctance resolver consisting of 135 and 135 is employed, the rotational position control of the outer rotor members 121 and 121, that is, the arms Al and A 2 'can be performed with high accuracy.

[0259] Although a resolver is used here to detect the rotation of the inner rotor 130, the detector can be placed on the atmosphere side inside the partition wall 13, so a servo motor generally used for high-accuracy positioning is highly accurate. Also, an optical encoder that is employed as a position detecting means for smooth and smooth driving, a magnetic encoder using a magnetoresistive element, or the like can be used. The cylindrical member 123 that constitutes the outer rotor of the (first) direct drive motor D4 closest to the upper end of the motor system that works in this embodiment is detachably attached to the housing (here, the cylindrical member 110). Thus, the outer diameter part 110a of the mounting seat surface of the bearing holder 107 in the cylindrical member 110 is positioned in the radial direction from the thin cylindrical part 13b. . Therefore, if the bearing holder 10 7 is removed, the cylindrical member 123 of the direct drive motor D4 and the bearing 119 ' The cylindrical member 123 of the supported direct drive motor D3 can be removed from the partition wall 13 integrally with the outer rotor members 121 and 121 ', and then the direct drive motors D2 and D1 can be removed. As a result, it can be easily inspected and removed, thus improving maintainability. Furthermore, since only the bearing holder 107 needs to be removed, a leak check or the like is not required at the time of reassembly without the need to remove the partition wall structure, and assemblability is improved.

[0260] In the housing of the present embodiment, the first main body 12 and the second main body 112 are connectable in an arbitrary phase in the axial direction, that is, two adjacent direct drive motors Dl, Each unit commonly used in D2, D3, and D4 is detachably bolted. The first main body 12 includes, in order from the disk 10, the angle detector of the direct drive motor D1, the stator of the direct drive motor D1, the stator of the direct drive motor D2, and the angle of the direct drive motor D2. In the order of the detector and the second body 112, the first main body 12 side force is also in order, the direct drive motor D3 axis angle detector, direct drive motor D3 axis stator, direct drive motor D4 stator In addition, the angle detectors of the direct drive motor D4 can be arranged in this order, and the angle of the angle detector with respect to the stator can be easily adjusted for each axis. Therefore, if a facility for rotating the reference motor rotor is prepared separately, the first main body or the second main body incorporating the motor stator and the rotation detector can be set in that equipment, so that the individual In addition, the angle adjustment of the angle detector with respect to the motor stator can be performed with high accuracy, so that deterioration of the angle positioning accuracy due to misalignment is prevented, adjustment after assembly is easy or unnecessary, and the present invention 4-axis coaxial The compatibility of the drive control circuit with the motor can be increased. In the above embodiment, the force described with reference to the example using the surface magnet type 32-pole 36-slot outer rotor brushless motor is limited to this type of motor. Not something

Any brushless motor can be used, and other magnetic pole types such as a permanent magnet embedded type, other slot combinations, or an inner rotor type may be used.

[0261] Further, as a countermeasure against interference of each axis, a configuration may be adopted in which the number of rotor poles and the number of slots of adjacent axes in the axial direction are different. For example, in the case of 4-axis coaxial, the first axis is 32 poles 36 Lot, the second axis is 24 poles 27 slots, the 4-axis coaxial, the first axis and the third axis 32 poles 3 6 slots, the second axis and the fourth axis 24 poles 27 slots, Mutual interference such as generation of thrust in the rotational direction on the rotor and magnetic coupling device due to the magnetic field of each axis can be prevented.

[0262] The rotor permanent magnet is a neodymium (Nd-Fe-B) magnet, and nickel coating is used as an example of coating to improve corrosion resistance. This material is not limited to the surface treatment, but is changed as appropriate depending on the environment in which it is used. For example, samarium-cobalt (Sm'Co) is less susceptible to high temperature demagnetization depending on the temperature conditions during beta-out System magnets should be used, and if used in ultra-vacuum, a titanium nitride coating with a high outgas barrier should be applied.

[0263] In addition, the yoke is made of low-carbon steel and explained with an example of nickel plating. This material is not limited to surface treatment, and is appropriately changed depending on the environment used. Especially for surface treatment, if it is used in ultra-vacuum, it should be applied with force with few pinholes such as Zen plating, clean soldering, and titanium nitride coating.

[0264] Also, bearings 19, 19 ', 119, and 119' have been described using examples of grease lubricated four-point contact ball bearings for vacuum lubrication, but they are not limited to this type, material, and lubrication method. It can be changed as appropriate according to the environment, load conditions, rotational speed, etc., and may be a cross roller bearing. In the case of a 4-axis coaxial motor, another bearing is used to further increase mechanical rigidity. If a multi-point contact bearing cannot be used, such as when rotating at high speeds, a bearing that supports the rotor of each shaft and another bearing can be preloaded as a deep groove ball bearing or an angular bearing. It is also possible to use a structure that hangs, or when used in ultra-vacuum, it is possible to use a metal lubrication that does not release gas, such as a metal ring plated with a soft metal such as gold or silver. .

[0265] As an inner rotor that functions as a magnetic coupling, a permanent magnet and a back yoke are provided. Although described in the format used, the material and shape of the permanent magnet and the back yoke are not limited to this. For example, depending on the mass of the resolver and the frictional torque of the bearing, the number of poles may not be the same as that of the outer rotor, or the width may not be the same. A salient pole that does not use a permanent magnet is also acceptable.

Further, although an example in which a resolver is used as an angle detector has been described, it can be appropriately changed depending on manufacturing cost and resolution, and for example, an optical rotary encoder may be used.

[0266] Further, although examples in which grease lubricated four-point contact ball bearings are used as the bearings 33, 33 ', 133, 133' that rotatably support the rotation side of the angle detector have been described, If the multi-point contact bearing cannot be used, such as high-speed rotation or reduction of friction torque, it can be changed appropriately depending on the installation space, friction torque, rotation speed, etc., which is not limited to the lubrication method. For bearings, two deep groove ball bearings may be arranged for each shaft to apply preload.

[0267] In addition, the material, shape, and manufacturing method of the structural components and partition walls arranged outside and in the other partition walls are appropriately changed depending on the manufacturing cost, the environment used, the load conditions, the configuration, and the like. is there.

In the motor system described above, the magnetic force coupling used in each rotor and rotation detector generates a thrust in the rotational direction by the magnetic flux leaking the magnetic coupling force used in the rotor, stator, and resolver of each axis. In this way, magnetic shields for shielding each other's magnetic field are arranged between the rotors of each shaft, and the rotor, stator, and resolver force of each shaft interfere with each other's resolver. However, by arranging magnetic shields to shield each other's electromagnetic fields, or by changing the number of rotor slots and the number of stator slots between adjacent shafts in the axial direction, Since magnetic interference generated between the axes is prevented, the axial length of each axis and the axial distance of each axis can be shortened. Therefore, a multi-axis coaxial motor system such as 4-axis coaxial or 4-axis coaxial can be configured with a reduced overall axial length. In particular, in a system using a multi-axis direct drive motor such as a 4-axis coaxial system, two frog redder arm robots that can be positioned with high accuracy without greatly changing the chamber structure can be installed. Performance and availability can be increased. It can also be used for motor systems with more than 4 axes. Needless to say, you can.

[0268] The present invention has been described above with reference to the embodiment. However, the present invention should not be construed as being limited to the above embodiment, and can be appropriately changed or improved. The For example, the direct drive motor of the present embodiment can be used not only in a vacuum atmosphere but also in an atmosphere outside the atmosphere. For example, in the case of a semiconductor manufacturing process, reactive gas for etching may be introduced into the vacuum chamber after evacuation, but in the direct drive motor of this embodiment, the inside and outside are shielded by the partition walls. Therefore, there is no possibility that the motor coil or the insulating material will be etched.

[Sixth embodiment]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 38 is a perspective view of a frog redder arm type transport device using a direct drive motor that works in the present embodiment. In FIG. 38, two direct drive motors Dl and D2 are connected in series. A first arm A1 is connected to the rotor of the lower (first) direct drive motor D1, and a first link L1 is pivotally connected to the tip of the first arm A1. On the other hand, the second arm A2 is connected to the rotor of the upper (second) direct drive motor D2, and the second link L2 is pivotally connected to the tip of the second arm A2. The links LI and L2 are pivotally connected to a table T on which Ueno and W are placed.

[0269] The force apparent from Fig. 38 If the rotors of the direct drive motors Dl and D2 rotate in the same direction, the table T also rotates in the same direction. If the powerful rotor rotates in the opposite direction, the table T The direct drive motors Dl and D2 are approaching or separating from each other. Therefore, if the direct drive motors Dl and D2 are rotated at an arbitrary angle, the wafer W can be transferred to an arbitrary two-dimensional position within a range where the table T can reach. Thus, for example, a wafer transfer arm placed in a vacuum chamber in a semiconductor manufacturing apparatus, for example, an apparatus having a plurality of arms such as a scalar type or a frog redder type shown in the figure, particularly requires a plurality of rotary motors. It becomes. In a vacuum environment, the surface area of contact with the outside world should be minimized, and at the same time, the number of mounting holes for motors, etc., should be minimized to make effective use of space. Also, in order to transport wafer W horizontally and with minimal vibration, the moment acting on the tip of the arm is firmly held by the rotor support. It is necessary to have. Therefore, a plurality of direct drive motors Dl and D2 are connected coaxially at the housing part, and the connection part is tightly joined with a seal (tightly joined by welding, O-ring, metal gasket, etc.), and the motor rotor is arranged. It is necessary to separate the open space from the housing external space.

[0270] In addition, in order to convey wafer W straight horizontally and with less vibration, the moment acting on the tips of arms Al and A2 must be firmly held by the rotor support. In addition, when driving multiple axes in a vacuum environment, if the current rotation position of the arm is not recognized when the power is turned on, the arm Al, A2, etc. will be hit against the wall of the vacuum chamber or the shatter of the vacuum chamber. There is a possibility. A motor system in which a direct drive motor capable of meeting such requirements is connected to the same shaft will be described.

FIG. 39 is a view of the configuration of FIG. 38, taken along the Π-Π line and viewed in the direction of the arrow. With reference to FIG. 39, the internal structure of the two-axis motor system will be described in detail. First, the direct drive motor D1 will be described. A hollow cylindrical main body 12 fitted into the central opening 10a of the disk 10 installed on the surface plate G and fixed to each other by bolts 11 has a cup-shaped partition wall 13 attached to the upper end thereof. The center of the body 12 is used to pass the wiring to the stator. Can be used. The main body 12 and the disk 10 constitute a housing.

[0273] The partition wall 13 is made of stainless steel, which is a non-magnetic material. The partition wall 13 extends from the peripheral edge of the wall portion 13a and the direct drive motors Dl and D2 in the axial direction. It consists of an existing thin cylindrical portion 13 b and a holder 15. Therefore, the partition wall 13 is commonly used for the direct drive motors Dl and D2. The lower end of the cylindrical portion 13b is joined to a holder 15 so as to be sealed by TIG welding, and the holder 15 is fixed to the disc 10 with bolts 16. Here, by setting the welded portion of the cylindrical portion 13b and the holder 15 to substantially the same thickness, it is possible to suppress heat from escaping only to the component on one side and to weld the fitting portion uniformly. The contact surface between the holder 15 and the disc 10 is provided with a groove force that fits the seal member. After the seal member OR is fitted into the groove, the holder 15 and the disc 10 are fastened by the bolt 16. As a result, the fastening part is isolated from the atmospheric force. The partition wall 13 is made of austenitic stainless steel SUS316, which has high corrosion resistance, and is particularly magnetic. The holder 15 is also made of SUS316 because of its weldability with the partition wall 13.

[0274] Further, the partition wall 13 and the holder 15 are hermetically joined, and the holder 15 and the disk 10 and the disk 10 and the surface plate G are hermetically sealed by O-rings OR, respectively. Therefore, the internal space surrounded by the disk 10 and the partition wall 13 is also hermetically sealed. The partition wall 13 is not necessarily made of a nonmagnetic material. Further, instead of using an O-ring OR, the members may be hermetically sealed by electron beam welding or laser beam welding.

A bearing holder 17, which is a separate body, is fixed by bolts 18 on the outer peripheral upper surface of the disk 10 that is an atmospheric outer member. The bolt 18 is disposed outside the cylindrical member 23 and exposes its head. An outer ring of a four-point contact ball bearing (first bearing) 19 used in a vacuum is fitted to the bearing holder 17 in a fitting manner, and is fixed by a bolt 20 via an annular bearing restraint BH. On the other hand, the inner ring of the bearing 19 is fitted to the outer periphery of the first outer rotor 21 and is fixed by a bolt 22 via an annular bearing restraint BH. That is, the first outer rotor 21 is rotatably supported by the bearing 19 and the partition wall 13 by the bearing 19, and a cylindrical member 23 that supports the arm A1 (FIG. 38) is formed on the upper surface thereof. It is fixed by 24. Here, the bolt 24 can fasten a magnetic shield plate 25 (indicated by a dotted line) extending radially inward to the cylindrical member 23 together. 1st outer port The rotor 21 and the cylindrical member 23 constitute an outer rotor.

[0275] The disc 10 and the bearing holder 17 are made of austenitic stainless steel having high corrosion resistance, and the disc 10 also serves as a fitting and fixing device with the surface plate G, which is a chamber, on its lower surface. A groove 10b is provided to fill the O-ring OR.

[0276] The bearing 19 may be made of metal lubricated by plating a soft metal such as gold or silver on the inner ring and the outer ring so that no outgassing occurs even in vacuum, or a four-point contact ball. Because it is a bearing, it can receive a moment in the direction in which the first outer rotor 21 tilts from the arm A1, but it is not limited to the four-point contact type, and cross rollers, cross balls, and cross taper bearings can also be used. Yes, it can be used under preload conditions, or fluorine film treatment (DFO) can be performed to improve lubricity!ヽ.

[0277] The first outer rotor 21 includes a permanent magnet 21a, an annular yoke 21b made of a magnetic material to form a magnetic path, and a non-magnetic material for mechanically fastening the permanent magnet 21a and the yoke 21b. It consists of a wedge (not shown). Permanent magnet 21a has a configuration of 32 poles, each of which has 16 poles of N poles and S poles alternately made of magnetic metal, and is divided into segments. Each of the permanent magnets 21a has a sector shape. Although the inner and outer diameter arc centers are the same, the tangential intersection of the circumferential end faces is closer to the permanent magnet 21a, and the wedge is tightened from the outer diameter side of the yoke 21b with a screw to tighten the permanent magnet 21a to the yoke. Signed to 21b. With this configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. Permanent magnet 21a is a high energy product of neodymium (Nd—Fe—B ) Series magnets with nickel coating to enhance corrosion resistance. The yoke 21b is made of a low-carbon steel having high magnetism, and is plated with nickel to improve wear resistance and corrosion resistance and prevent wear during bearing replacement after processing and molding.

[0278] The first outer rotor 21 has a surface for fitting and fixing the inner ring of the bearing 19 and the cylindrical member 23. The four-point contact ball bearing 19 is a very thin bearing, and its rotational accuracy and friction torque are greatly affected by differences in accuracy and linear expansion coefficient of the assembled parts. Therefore, in the case of the present embodiment, the inner ring of the bearing 19 which is a rotating ring is an interference fit or an intermediate fit to the yoke 21b which is easy to obtain processing accuracy and whose linear expansion coefficient is substantially the same as the bearing ring material of the bearing. The outer ring of the bearing 19, which is a fixed ring, is fitted to the austenitic stainless steel bearing holder or aluminum boss to prevent the bearing 19 from rotating and the friction torque from increasing due to temperature rise. ing.

[0279] A first stator 29 is disposed on the inner side in the radial direction of the partition wall 13 so as to face the inner peripheral surface of the first outer rotor 21. The first stator 29 is attached to a cylindrically deformed lower portion of a flange portion 12a extending in the radial direction at the center of the main body 12. The first stator 29 is formed of a laminated material of electromagnetic steel plates and is insulated from each salient pole. As a process, the motor coil is concentrated after the bobbin is fitted. The outer diameter of the first stator 29 is approximately the same as or smaller than the inner diameter of the partition wall 13.

[0280] The first inner rotor 30 is disposed on the radially inner side of the first stator 29. The first inner rotor 30 is rotatably supported by a ball bearing 33 with respect to a resolver holder 32 that is bolted to the outer peripheral surface of the main body 12. A permanent magnet 30a is attached to the outer peripheral surface of the first inner rotor 30 via a knock 30b. The permanent magnet 30a is composed of 32 poles in the same manner as the permanent magnet 21a of the first outer rotor 21, and 16 magnets of N poles and S poles are alternately made of magnetic metal. Accordingly, the first inner rotor 30 is rotated in synchronism with the first outer rotor 21 driven by the first stator 29.

[0281] The bearing 33 that rotatably supports the first inner rotor 30 is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, the direct drive motor D1 can be made thinner because only one bearing is required. Since the inside of the partition wall 13 is an atmospheric environment, grease lubrication based on general bearing steel and mineral oil is recommended. The used bearing can be applied.

[0282] Resolver rotors 34a and 34b are assembled as detectors for measuring the rotation angle on the inner periphery of the first inner rotor 30, and the resolver stator 35 is disposed on the outer periphery of the resolver holder 32 so as to oppose it. In this embodiment, the high-resolution incremental resolver stator 35 and the absolute resolver stator 36 that can detect the position of the rotor in one rotation are arranged in two layers. /! For this reason, even when the power is turned on, the rotational angle of the absolute resolver rotor 34b is known, no return to origin is required, and the electrical phase angle of the magnet with respect to the coil increases, so the drive current of the direct drive motor D1 The rotation angle used for control can be detected without using a pole detection sensor.

[0283] The resolver holder 32 and the first inner rotor 30 are made of carbon steel, which is a magnetic material, so that electromagnetic noise from the motor field and motor coil is not transmitted to the resolver stators 35, 36 that are angle detectors. In order to prevent fouling after processing and molding, chromate plating is applied.

The high-resolution variable reluctance resolver used in the present embodiment has an incremental resolver rotor 34a having a plurality of slot teeth having a constant pitch, and the outer peripheral surface of the incremental resolver stator 35. Are provided with teeth shifted in phase with respect to the incremental resolver rotor 34a at each magnetic pole parallel to the rotation axis, and a coil is wound around each magnetic pole. When the incremental resolver rotor 34a rotates together with the first inner rotor 30, the reluctance between the incremental resolver stator 35 and the magnetic pole changes, and the fundamental wave component of the change in reluctance becomes n cycles in one revolution of the incremental resolver rotor 34a. In this way, the reluctance change is detected, digitalized by the resolver control circuit shown in FIG. 40, and used as a position signal, so that an incremental resolution is obtained. The rotation angle (or rotation speed) of the rotor 34a, that is, the first inner rotor 30 is detected. The resolver rotors 34a and 34b and the resolver stators 35 and 36 constitute a detector.

[0284] According to the present embodiment, the first inner rotor 30 rotates at the same speed by the magnetic coupling action with respect to the first outer rotor 21, that is, rotates with the first outer rotor 21, so that the first outer rotor 21 rotates. The corner can be detected through the bulkhead 13. Further, in the present embodiment, the resolver alone has the bearing 33 without using the parts forming the motor and the uzing, and therefore, the eccentricity adjustment with the resolver alone is performed before the resolver coil is assembled into the housing. Since accuracy adjustment such as position adjustment can be performed, there is no need to provide adjustment holes or notches on both flanges of the housing. In addition, the rotating wheel of the bearing device 19 that is rotatably supported by the first outer rotor 21 is fitted into a rotor yoke 21b that is easy to obtain machining accuracy and has the same linear expansion coefficient as the driving wheel of the bearing device 19. In addition, the rotation accuracy can be improved and the friction torque can be prevented from changing due to temperature changes.

[0285] Next, the force for explaining the direct drive motor D2 Here, the main body 12 constitutes a housing. The above-described cylindrical member 23 of the direct drive motor D1 extends upward to a position where it overlaps with the direct drive motor D2, and has a four-point contact ball bearing (no. 2 bearing) The outer ring of 19 'is fitted in a fitting manner, and is fixed by a bolt 20' via an annular bearing restraint BH '. On the other hand, the inner ring of the bearing 19 ′ is fitted to the outer periphery of the second outer rotor 21, and is fixed by bolts 22 via an annular bearing restraint BH.

[0286] Here, the bolt 22 'and the magnetic shield plate 41 (indicated by a dotted line) extending radially inward can be fastened together. The second outer rotor 21 ′ is rotatably supported by the bearing 19 ′ with respect to the cylindrical member 23 and the partition wall 13, and the ring-shaped member 23 ′ supporting the arm A 2 (FIG. 38) is It is fixed on the top surface with bolts 24 '. Further, the bolt 24 'has a magnetic shield plate 25' extending radially inward and fastened together with the ring-shaped member 23 '. In the forcefully assembled state, the cylindrical member 23 ′ integrated with the second outer rotor 21 ′ covers the bolt 20 ′ with axial outward force and radial outward force. The second outer rotor 21 ′ and the cylindrical member 23 ′ constitute an outer rotor. [0287] The magnetic shield plates 41 and 25 'can be subjected to nickel plating in order to improve the anti-corrosion and corrosion resistance after press molding the SPCC steel plate, which is a magnetic material. The magnetic shield plates 4 1 and 25 are interposed between the first outer rotor 21 and the second outer rotor 21 to form a magnetic shield, and each other due to magnetic flux leakage from them! Has a function to prevent the bag from being carried around. That is, the magnetic shield plate 25 ′ can be fastened to the yoke 21b ′ with the ring-shaped member 23 ′, which is a nonmagnetic material, interposed therebetween, thereby preventing generation of an unnecessary magnetic circuit. Since the magnetic shield plates 41 and 25 can prevent magnetic interference between the rotors, the overall axial length can be reduced even though it is a two-axis coaxial motor system. The magnetic shield plate 41 can prevent external force from attracting foreign matter.

[0288] Bearing 19 'is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, since the direct drive motor D2 requires only one bearing, the biaxial coaxial motor of the present invention can be made thinner. The inner and outer rings are made of martensitic stainless steel, which has high corrosion resistance and can be hardened by quenching. The rolling elements are ceramic balls, and the lubricant is vacuum grease that does not solidify even under vacuum.

[0289] The second outer rotor 21 'mechanically fastens the permanent magnet 21a', the annular yoke 21b 'made of a magnetic material to form a magnetic path, and the permanent magnet 21a' and the yoke 21b '. It is made up of a wedge (not shown). Permanent magnet 21a 'is a segment type with a configuration of 32 poles, with 16 N-pole and S-pole magnets alternately made of magnetic metal and divided into poles, each of which has a sector shape. The center of the arc of the inner and outer diameter is the same. It is fastened to the yoke 21b '. With such a configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. Permanent magnet 21a 'is a high energy product neodymium (Nd-Fe-B) based magnet, which is coated with nickel to enhance corrosion resistance. Yoke 21b 'is made of low-carbon steel with high magnetic properties, and is plated with nickel to improve wear resistance and corrosion resistance after machining and to prevent wear during bearing replacement.

[0290] Further, the second outer rotor 21 'has a surface for fitting and fixing the inner ring of the bearing 19' and the ring-shaped member 23 '. The four-point contact ball bearing 19 'is a very thin bearing, and its rotational accuracy and friction torque are greatly affected by differences in the accuracy and linear expansion coefficient of the assembled parts. Therefore, in the case of the present embodiment, the inner ring of the bearing 19 ′ is tightly fitted or intermediately fitted to the yoke 21b, which is easy to obtain machining accuracy and has the same linear expansion coefficient as the bearing ring material of the bearing. The outer ring is made into a clearance fit with an austenitic stainless steel bearing holder or an aluminum boss, thereby preventing a decrease in rotational accuracy of the bearing 19 ′ and an increase in friction torque due to a temperature rise.

[0291] On the radially inner side of the partition wall 13, a second stator 29 'is disposed so as to face the inner peripheral surface of the second outer rotor 21'. The second stator 29 ′ is attached to the upper part of the flange 12 a that extends in the radial direction in the center of the main body 12, and is formed of a laminated material of electromagnetic steel sheets, and each salient pole is insulated. As shown, the motor coil is concentrated after the bobbin is fitted. The outer diameter of the second stator 29 ′ is approximately the same as or smaller than the inner diameter of the partition wall 13.

[0292] A second inner rotor 30 'is arranged inside the second stator 29' in the radial direction. The second inner rotor 30 ′ is rotatably supported by a ball bearing 33 ′ with respect to a resolver holder 32 ′ bolted to the outer peripheral surface of the main body 12. A permanent magnet 30a ′ is attached to the outer peripheral surface of the second inner rotor 30 ′ via a back yoke 30b ′. The permanent magnet 30a ′ has a configuration of 32 poles, like the permanent magnet 21a ′ of the second outer rotor 21 ′, and has 16 magnetic poles each having N poles and S poles alternately. Accordingly, the second inner rotor 30 ′ is rotationally driven by the second stator 29 ′ in synchronization with the second outer rotor 21 ′.

[0293] The bearing 33 'that rotatably supports the first inner rotor 30' is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. Use this type of bearing Therefore, the direct drive motor D2 can be made thinner because only one bearing is required. Since the inside of the partition wall 13 is an atmospheric environment, it is possible to use a bearing using grease lubrication based on general bearing steel and mineral oil.

[0294] The resolver rotors 34a 'and 34b' are assembled as detectors for measuring the rotation angle on the inner periphery of the second inner rotor 30 ', and the outer periphery of the resolver holder 32' is opposed to it. In this embodiment, the resolution of the resolver stator 35 ', 36' is high resolution incremental resolver stator 35, and the absolute resolver stator 36 'that can detect the position of the rotor in one rotation. Are arranged in two layers. For this reason, even when the power is turned on, the rotational angle of the absolute resolver rotor 34b 'can be known, no return to origin is required, and the electrical phase angle of the magnet with respect to the coil is different, so the relative rotational angle of the direct drive motor D2 is This is possible without using a pole detection sensor.

[0295] The resolver holder 32 'and the second inner rotor 30' are magnetic bodies so that electromagnetic noise from the motor field and the motor coil is not transmitted to the resolver stators 35 'and 36' that are angle detectors. Carbon steel is used as a material, and chromate plating is applied after processing to prevent fouling.

According to the present embodiment, the second inner rotor 30 ′ rotates at the same speed by the magnetic coupling action with respect to the second outer rotor 21 ′, that is, rotates with the rotation angle of the second outer rotor 21 ′. Can be detected through the partition wall 13. Further, in the present embodiment, the parts constituting the motor, the bearing 33 is provided as a single resolver without using uzing. Since it is possible to adjust the accuracy of the resolver coil position, etc., there is no need to provide adjustment holes or notches on both flanges of the housing. Also, a bearing device that rotatably supports the second outer rotor 21 ′ By fitting the 19 'rotating wheel to the rotor yoke 21b', which is easy to achieve machining accuracy and has the same linear expansion coefficient as the drive wheel of the bearing device 19 ', the rotational accuracy is improved and the friction torque due to temperature changes is reduced. It is possible to prevent fluctuations.

In the high-resolution variable reluctance resolver used in the present embodiment, the incremental resolver rotor 34a ′ has a plurality of slot tooth rows having a constant pitch, and the outer circumference of the incremental resolver stator 35. The surface is provided with teeth that are shifted in phase with respect to the incremental resolver rotor 34a ′ at each magnetic pole parallel to the rotation axis, and a coil is wound around each magnetic pole. When the incremental resolver port 34a rotates together with the second inner rotor 30 ', the reluctance between the magnetic poles of the incremental resolver stator 35 changes, and the basic reluctance change occurs with one rotation of the incremental resolver rotor 34a. The reluctance change is detected so that the wave component has n cycles, is digitalized by the resolver control circuit shown in FIG. 40, and is used as a position signal, so that the incremental resolver rotor 34a ' 2The rotation angle (or rotation speed) of the inner rotor 30 'is detected. The resolver rotors 34a, 34b and the resolver stators 35, 36 constitute a detector.

[0297] According to the present embodiment, the magnetic shield plates 25 and 41 are arranged between the first outer rotor 21 and the second outer rotor 21 'to suppress mutual magnetic interference. , Malfunctions such as erroneous driving and accompanying people can be avoided. In addition, the outer peripheral edge 12b of the flange portion 12a extending between the direct drive motors Dl and D2 in the main body 12 is made of carbon steel, which is a magnetic material, between the first stator 29 and the second stator 29 ′. In order to prevent the first outer rotor 21 or the second outer rotor 21 ′ from generating a thrust in the wrong rotation direction due to the influence of the leakage magnetic flux, the magnetic fields that shield each other's magnetic field are included. Functions as a shield.

[0298] The first stator 29 and the second stator 29 'are arranged vertically with the flange portion 12a as the center, and the resolver is arranged radially inward thereof. The main body 12 has a hollow structure, and the flange portion 12a has at least one radial through hole 12d communicating with the center through which the motor wiring is drawn out to the center of the main body 12. It has a structure. On the other hand, at least one notch 12e, 12e is provided at each end of the main body 12, and the resolver wiring is drawn out to the center of the main body 12 through these. Such a structure In this way, it is possible to arrange the resolver of the direct motor D1, the stator 29, the stator 29 of the direct motor D2, and the resolver in this order from the housing side. Can be adjusted. Therefore, if a separate facility for rotationally driving the reference outer rotor is prepared, the angle of the resolver relative to the stator can be adjusted with high accuracy by setting the main body 12 incorporating the stator and resolver in the facility. Therefore, it is possible to prevent the angle positioning accuracy from being lowered due to the deviation of the commutation, and to improve the compatibility of the drive control circuit with the two-axis coaxial motor of the present invention.

FIG. 41 is a block diagram showing a drive circuit for direct drive motors Dl and D2. When a motor rotation command is also input to the external computer force, the motor control circuit DMC1 for the direct drive motor D1 and the motor control circuit DMC2 for the direct drive motor D2 are each sent from the CPU to the three-layer amplifier (AMP). The drive signal is output, and the drive current is supplied to the direct drive motors Dl and D2 with a three-layer amplifier (AMP) force. As a result, the outer rotors 21 and 21 ′ of the direct drive motors Dl and D1 rotate independently to move the arms A1 and A2 (FIG. 38). When the outer rotor 21, 21 'rotates, the resolver signal is output from the resolver stator 35, 36, 35, 36, which has detected the rotation angle as described above, and is output to the resolver digital converter (RDC). The CPU input after digital conversion judges whether or not the outer rotor 21, 21 'has reached the command position, and when it reaches the command position, it stops the drive signal to the 3-layer amplifier (AMP). Stop rotation of outer ports 21, 21 '. This enables servo control of the outer rotors 21, 21 '.

[0300] When driving multiple axes in a vacuum environment, if the current rotation position of arms A1 and A2 is not recognized when the power is turned on, the arm A1 or the like is placed on the wall of the vacuum chamber or the shatter of the vacuum chamber. In this embodiment, the absolute resolver stators 36 and 36 'that detect the absolute position of one rotation of the rotating shaft, and the incremental resolver stator 35 and that detect a rotational position with finer resolution are used in this embodiment. 35, a variable reluctance resolver is used, so that the rotational position of the outer rotors 21 and 21, that is, the arms Al and A2, can be controlled with high accuracy. [0301] It should be noted that here a force detector that employs a resolver for detecting the rotation of the inner rotor 30 can be arranged on the atmosphere side inside the partition wall 13, so that a servo motor generally used for high-precision positioning is highly accurate and smooth. An optical encoder adopted as a position detecting means for driving, a magnetic encoder using a magnetoresistive element, or the like can also be used. Next, a disassembled aspect of the motor system that works according to the present embodiment will be described. 42 to 45 are cross-sectional views showing a disassembly process of the motor system that works according to the present embodiment, and FIGS. 46 to 49 are perspective views showing a disassembly process of the motor system that works according to the present embodiment. It is.

[0302] In the motor system according to the present embodiment, it is assumed that the bearing 19 of the direct drive motor D1 needs to be inspected or replaced. In such a case, a tool (not shown) is engaged with the hexagon bolt 18 with the exposed head to loosen it. Then, as shown in FIG. 42, since the bearing holder 17 can be separated from the disk 10, the direct drive motors Dl and D2 can be pulled upward together (see FIG. 46). Here, since the partition wall 13 and the disk 10 remain assembled, their airtightness has not collapsed, and it is not necessary to perform a leak check or the like when reassembling.

[0303] At this time, since the lower surface of the direct drive motor D1 is exposed, the lubrication state and the like of the bearing 19 can be inspected. If it is determined that the bearing 19 is about to be replaced by a strong inspection, the bearing 19 needs to be replaced.

When replacing the bearing 19, remove the bolt 22 from the yoke 21b as shown in Fig. 43 (see Fig. 47). Then, since the bearing restraint BH that has fixed the inner ring of the bearing 19 can be separated, the bearing 19 can be removed integrally with the bearing holder 17 as shown in FIG. 44 (see FIG. 48).

[0304] If the bolt 20 is removed from the bearing holder 17 in such a state, the outer ring of the bearing 19 can be fixed and the bearing restraint BH can be separated, so that the bearing 19 can be separated from the bearing holder 17. Assembly may be performed in the reverse order of the above.

If it is necessary to inspect or replace the bearing 19 'of the direct drive motor D2, the cylindrical member 23' can be separated by removing the bolt 24 'from the yoke 21b' in FIG. At this time, since the bearing 19 'is visible, its lubrication state and the like can be inspected. The

[0305] If it is determined that the bearing 19 'is about to be replaced by vigorous inspection, removing the bolt 20' from the cylindrical member 23 will remove the bearing restraint BH 'that secured the outer ring of the bearing 19'. Therefore, the bearing 19 ′ can be separated integrally with the yoke 21b ′.

Further, when the bolt 22 ′ is also removed from the yoke 21b ′, the bearing restraint BH ′ that has fixed the inner ring of the bearing 19 can be separated, so that the bearing 19 ′ can be separated from the yoke 21b ′. Assembly may be performed in the reverse order. Figures 45 and 12 show the direct drive motors Dl and D2 completely disassembled.

[0306] According to this embodiment, the minimum inner diameter force of the first outer rotor 21 of the direct drive motor D1 and the second outer rotor 21 'of the direct drive motor D2 is larger than the maximum outer diameter of the partition wall 13. In addition, the yoke 21b of the direct drive motor D1 is attached to the disk 10 by the bolt 18 via the bearing holder 17, and further, the direct drive motor D1 is connected to the cylindrical member 23 of the direct drive motor D1 via the bearing 19 '. Since the yoke 21b 'of D2 is installed, the direct drive motor Dl and D2 can be separated from the disk 10 and the bulkhead 13 together with the bearing holder 17 by removing the bolt 18, and the airtight structure of the bulkhead 13 must be disassembled. Easily perform maintenance work on the direct drive motor D1

FIG. 50 is a cross-sectional view showing a four-axis coaxial motor system that works on a modification of the present embodiment. In the modified example shown in FIG. 50, the force formed by directly arranging two sets (four in total) of direct drive motors Dl and D2 The individual direct drive motors are the same as those shown in FIG. The same reference numerals are given to the parts, and the description is omitted.

In the present embodiment, a partition wall holder 113a is hermetically coupled to the upper disk part 110 attached to the upper surface of the main body 12 connected in series via an O-ring OR, and a thin cylinder is formed on the outer peripheral surface thereof. The upper end of 113b is TIG welded. The lower end of the thin-walled cylinder 113b is TIG welded to the holder 15 as in the above-described embodiment. The partition wall holder 113a, the thin cylinder 113b and the holder 15 constitute a partition wall. This is commonly used for the four direct drive motors.

[0308] The upper surface of the disc portion 110 is closed by the lid member 101, and the bearing is attached to the outer periphery thereof. The holder 107 supports the bearing 19. The disc portion 110, the lid member 101, and the bearing holder 107 are made of austenitic stainless steel having high corrosion resistance. The main body 12, the disc 10, and the upper disc portion 110 constitute a housing.

In the lower direct drive motors Dl and D2, a separate bearing holder 17 is fixed by bolts 18 on the outer peripheral upper surface of the disk 10 which is an atmospheric outer member. The first outer rotor 21 is supported by the bearing 19 with respect to the bearing holder 17. The second outer rotor 21 ′ is supported by the bearing 19 ′ with respect to the cylindrical member 23.

[0309] On the other hand, in the upper direct drive motors Dl and D2, a bearing holder 107 is fixed by bolts 118 on the outer peripheral upper surface of the upper disc portion 110 that is an atmospheric outer member. The first outer rotor 21 is supported by the bearing 19 with respect to the bearing holder 17. The second outer port 21 ′ is supported by the bearing 19 ′ with respect to the first outer rotor 21.

The minimum inner diameter of the first outer rotor 21 of the direct drive motor D1 and the second outer rotor 21 'of the direct drive motor D2 is larger than the maximum outer diameter of the partition wall 13, and the upper disk part 110 is separated. The mounting outer peripheral surface of the bearing holder 107 is located on the inner side in the radial direction from the thin cylinder 113b. Therefore, if the bearing holder 107 is removed from the upper disk part 110, the two outer rotors 21, 21 at the upper part are connected. The upper disk part 110 can be extracted upward without disassembling, and if the bearing holder 17 is further removed from the disk 10, the lower two outer rotors 21, 21 ' Can be extracted upward without disassembling. Therefore, it is possible to facilitate the maintenance work without the need to disassemble the airtight structure by the partition wall 13 during maintenance such as inspection and replacement of the bearing.

[0310] In the present embodiment, the magnetic shield plates 25 'and 25' are arranged between the second outer rotors 21 and 21 at the center, so that mutual magnetic interference is suppressed. This avoids malfunctions such as erroneous driving and companionship. Between the main bodies 12 and 12, a magnetic shield plate 125 whose outer peripheral force extends in the radial direction to the inside of the thin cylinder 113b is disposed. The magnetic shield plate 125 is made of carbon steel, which is a magnetic material, and is interposed between the second stators 29 ′ and 29 ′, so that the adjacent second outer rotor 21 ′ is affected by the leakage magnetic flux. , 21 'functions as a magnetic shield that shields the magnetic field of each other so as not to generate a thrust in the wrong rotation direction. In this way, coupled with the effects of other magnetic shields 25, 41, 12b, Although it is a 4-axis coaxial, it can be configured with a reduced overall axial length.

[0311] FIG. 51 is a perspective view of a frog-leg-game transport apparatus using a four-axis coaxial motor system that is effective in the present embodiment. In FIG. 51, the first arm A1 is connected to the port of each direct drive motor D1, and the first link L1 is pivotally connected to the tip of the first arm A1. On the other hand, the second arm A2 is connected to the rotor of each direct drive motor D2, and the second link L2 is pivotally connected to the tip of the second arm A2. The links LI and L2 are pivotally connected to a table T on which the wafer W is placed. Each table T moves independently.

[0312] In the above embodiment, the force described using the example using the surface magnet type 32-pole 36-slot outer rotor brushless motor is not limited to this type of motor.

Any brushless motor can be used, and other magnetic pole types such as a permanent magnet embedded type, other slot combinations, or an inner rotor type may be used. Further, as a countermeasure against interference of each axis, a configuration may be adopted in which the number of rotor poles and the number of slots of adjacent axes in the axial direction are different. For example, in the case of 2-axis coaxial, the first axis is 32 poles and 36 slots, the second axis is 24 poles and 27 slots, and in the case of 4-axis coaxial, the first axis and the third axis are 32 poles and 3 6 slots. If the two axes and the fourth axis are configured with 24 poles and 27 slots, mutual interference such as generation of thrust in the rotational direction to the rotor and magnetic coupling device due to the magnetic field of each axis can be prevented.

[0313] The rotor permanent magnet is a neodymium (Nd-Fe-B) magnet, and nickel coating is used as an example of coating to improve corrosion resistance. This material is not limited to the surface treatment, but is changed as appropriate depending on the environment in which it is used. For example, samarium-cobalt (Sm'Co) is less susceptible to high-temperature demagnetization depending on the temperature conditions during beta-out. System magnets should be used, and if used in ultra-vacuum, a titanium nitride coating with a high outgas barrier should be applied.

[0314] In addition, the yoke is made of low-carbon steel and explained with an example of nickel plating. This material is not limited to the surface treatment and is appropriately changed depending on the environment used. If it is used in ultra-vacuum, especially for surface treatment For example, force with few pinholes-Zen plating, clean soldering, titanium nitride coating, etc. should be applied.

[0315] In addition, bearings 19 and 19 'have been described using an example of grease grease lubrication for four-point contact ball bearings. However, this is not limited to this type, material, and lubrication method. It can be changed as appropriate depending on conditions, rotational speed, etc., and it can be a cross roller bearing. In the case of a 4-axis coaxial motor, it can be supported by another bearing to further increase mechanical rigidity. If a multi-point contact bearing cannot be used, such as when rotating at high speeds, a bearing that supports the rotor of each shaft and another bearing may be configured to apply preload as deep groove ball bearings or angular bearings. When used in an ultra-vacuum, it is possible to use a metal-lubricated material that does not emit gas, such as a metal ring plated with a soft metal such as gold or silver.

[0316] Further, although the inner rotor functioning as a magnetic coupling has been described as a form using a permanent magnet and a back yoke, the material and shape of the permanent magnet and the back yoke are not limited thereto. For example, depending on the mass of the resolver and the friction torque of the bearing, the number of poles may not be the same as that of the outer rotor, or the width may not be the same. A salient pole that does not use a permanent magnet is also acceptable.

[0317] In addition, an example in which grease lubricated four-point contact ball bearings are used as the bearings 33 and 33 'that rotatably support the rotation side of the angle detector has been described, but this type and the lubrication method are limited. However, if the multi-point contact bearing cannot be used, such as high-speed rotation or reduction of friction torque, an anguilla bearing is a deep groove ball bearing. A structure may be used in which two are arranged for each axis to apply preload.

In addition, the material, shape, and structure of the structural parts and bulkheads placed outside and inside the other bulkheads The manufacturing method is appropriately changed depending on the manufacturing cost, the environment in which it is used, the load conditions, the configuration, and the like.

[0318] In the motor system described above, the thrust in the rotational direction is applied to the magnetic force coupling used for each rotor and rotation detector by the magnetic flux that also leaks the magnetic coupling force used for the rotor, stator, and resolver of each axis. Thus, magnetic shields for shielding each other's magnetic field are arranged between the rotors of each axis, or the electromagnetic fields generated by the rotor, stator and resolver force of each axis In order not to interfere with the resolver, a magnetic shield is provided to shield each other's electromagnetic field, or the number of rotor poles and the number of stator slots in the axially adjacent axes are changed. As a result, magnetic interference generated between the axes is prevented, so that the axial length of each axis and the axial distance of each axis can be shortened. Therefore, although it is a multi-axis coaxial motor system such as 2-axis coaxial or 4-axis coaxial, a configuration in which the overall axial length is suppressed is possible. In particular, in a system using a multi-axis direct drive motor such as a 4-axis coaxial system, two frog redder arm robots that can be positioned with high accuracy without greatly changing the chamber structure can be installed. Performance and availability can be increased.

[0319] The present invention has been described above with reference to the embodiment. However, the present invention should not be construed as being limited to the above embodiment, and can be appropriately changed or improved. The For example, the direct drive motor of the present embodiment can be used not only in a vacuum atmosphere but also in an atmosphere outside the atmosphere. For example, in the case of a semiconductor manufacturing process, reactive gas for etching may be introduced into the vacuum chamber after evacuation, but in the direct drive motor of this embodiment, the inside and outside are shielded by the partition walls. Therefore, there is no possibility that the motor coil or the insulating material will be etched.

[Seventh embodiment]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 52 is a perspective view of a frog redder arm type conveyance device using a direct drive motor that works in the present embodiment. In FIG. 52, two direct drive motors Dl and D2 are connected in series. The first arm A1 is connected to the rotor of the lower direct drive motor D1, and the first link L1 is pivotally connected to the tip of the first arm A1. On the other hand, the upper direct The second arm A2 is connected to the rotor of the drive motor D2, and the second link L2 is pivotally connected to the tip of the second arm A2. The links LI and L2 are pivotally connected to a table T on which the wafer W is placed.

[0320] Force apparent from Fig. 52 If the rotors of the direct drive motors Dl and D2 rotate in the same direction, the table T also rotates in the same direction, and if the powerful rotor rotates in the opposite direction, the table T The direct drive motors Dl and D2 are approaching or separating from each other. Therefore, if the direct drive motors Dl and D2 are rotated at an arbitrary angle, the wafer W can be transferred to an arbitrary two-dimensional position within a range where the table T can reach. Thus, for example, a wafer transfer arm placed in a vacuum chamber in a semiconductor manufacturing apparatus, for example, a device having a plurality of arms such as a scalar type or a frog redder type shown in the figure, particularly requires a plurality of rotary motors. It becomes. In a vacuum environment, the contact surface area with the outside world should be minimized, and at the same time, the number of mounting holes for motors, etc. should be minimized to make effective use of space. In addition, in order to transport the wafer W horizontally and with minimal vibration, it is necessary to firmly hold the moment acting on the tip of the arm with the rotor support. Therefore, a plurality of direct drive motors Dl and D2 are connected coaxially at the housing part, and the connection part is tightly joined with a seal (tightly joined by welding, O-ring, metal gasket, etc.), and the motor rotor is arranged. It is necessary to separate the open space from the housing external space.

[0321] In addition, in order to transport wafer W horizontally and with little vibration, the moment acting on the tips of arms Al and A2 must be firmly held by the rotor support. In addition, when driving multiple axes in a vacuum environment, if the current rotation position of the arm is not recognized when the power is turned on, the arm Al, A2, etc. will be hit against the wall of the vacuum chamber or the shatter of the vacuum chamber. There is a possibility. A motor system in which a direct drive motor capable of meeting such requirements is connected to the same shaft will be described.

[0322] This embodiment uses a surface magnet type 32-pole 36-slot outer rotor brushless type direct drive motor. The slot combination of 32 poles and 36 slots is generally known to have a large magnetic attraction force in the radial direction and a large vibration during rotation, although the cogging is small. is there . 2 ⁿ times (n is an integer) cancels out the magnetic attractive force in the radial direction. Therefore, vibration during rotation can be achieved without increasing the roundness and coaxiality of the stator and rotor and the rigidity of the mechanical parts. Can be made small and cogging is inherently small, so that a very smooth rotation can be obtained. On the other hand, by using such a very multi-pole motor, the electrical angle cycle is greater than the mechanical angle cycle, so positioning controllability is good. Therefore, it is suitable for a direct drive motor that drives a robot apparatus without using a speed reducer as in the present invention. In addition, since the thickness and salient pole width of the stator connecting portion and the yoke thickness of the rotor can be reduced without lowering the total magnetic flux, the direct drive motor having a thin and large diameter and narrow width as in the present invention is used. Is preferred.

FIG. 53 is a view of the configuration of FIG. 52 taken along the Π-Π line and viewed in the direction of the arrow. With reference to FIG. 53, the internal structure of the two-axis motor system will be described in detail. First, the direct drive motor D1 will be described. A hollow cylindrical main body 12 fitted in the central opening 10a of the disk 10 installed on the surface plate G and fixed to each other by bolts 11 has a cup-shaped partition wall 13 attached to the upper end thereof. The center of the main body 12 can be used to pass wiring to the stator. The main body 12 and the disk 10 constitute a housing.

[0324] The partition wall 13 is made of stainless steel, which is a non-magnetic material. The partition wall 13 extends from the peripheral edge of the wall 13 through the direct drive motors Dl and D2 in the axial direction. It consists of an existing thin cylindrical portion 13 b and a holder 15. Therefore, the partition wall 13 is commonly used for the direct drive motors Dl and D2. The lower end of the cylindrical portion 13b is joined to a holder 15 so as to be sealed by TIG welding, and the holder 15 is fixed to the disc 10 with bolts 16. Here, by setting the welded portion of the cylindrical portion 13b and the holder 15 to substantially the same thickness, it is possible to suppress heat from escaping only to the component on one side and to weld the fitting portion uniformly. The contact surface between the holder 15 and the disc 10 is provided with a groove force that fits the seal member. After the seal member OR is fitted into the groove, the holder 15 and the disc 10 are fastened by the bolt 16. As a result, the fastening part is isolated from the atmospheric force. The partition wall 13 is made of austenitic stainless steel SUS316, which has high corrosion resistance, and is particularly magnetic. The holder 15 is also made of SUS316 because of its weldability with the partition wall 13.

[0325] Furthermore, the partition wall 13 and the holder 15 are hermetically bonded, and the holder 15, the disk 10, and the circle. The plate 10 and the surface plate G are hermetically sealed by O-ring OR. Therefore, the internal space surrounded by the disk 10 and the partition wall 13 is hermetically sealed. The partition wall 13 is not necessarily made of a nonmagnetic material. Further, instead of using an O-ring OR, the members may be hermetically sealed by electron beam welding or laser beam welding.

A bearing holder 17 is fixed with bolts 18 on the outer peripheral upper surface of the disk 10. The bearing holder 17 is fitted with an outer ring of a four-point contact ball bearing 19 that is used in a vacuum, and is fixed by bolts 20. On the other hand, the inner ring of the bearing 19 is fitted to the outer periphery of the first outer rotor 21 and is fixed by bolts 22. That is, the first outer rotor 21 is rotatably supported with respect to the partition wall 13, and a cylindrical member 23 that supports the arm A1 (FIG. 52) is fixed by the bolt 24. Here, the bolt 24 fastens the magnetic shield plate 25 extending inward in the radial direction together with the cylindrical member 23.

[0326] The disc 10 and the bearing holder 17 are made of austenitic stainless steel, which has high corrosion resistance. The disc 10 also serves as a fitting and fixing device with the surface plate G, which is a chamber, on the bottom surface. A groove 10b is provided to fill the O-ring OR.

[0327] The bearing 19 may be made of metal lubricated by plating a soft metal such as gold or silver on the inner ring and the outer ring so as not to release outgas even in vacuum, or a four-point contact ball. Because it is a bearing, it can receive a moment in the direction in which the first outer rotor 21 tilts from the arm A1, but it is not limited to the four-point contact type, and cross rollers, cross balls, and cross taper bearings can also be used. Yes, it can be used in a pre-loaded state, or a fluorine-based coating to improve lubricity Processing (DFO) may be performed!ヽ.

[0328] The first outer rotor 21 includes a permanent magnet 21a, an annular yoke 21b made of a magnetic material to form a magnetic path, and a non-magnetic material for mechanically fastening the permanent magnet 21a and the yoke 21b. It consists of a wedge (not shown). Permanent magnet 21a has a configuration of 32 poles, each of which has 16 poles of N poles and S poles made of magnetic metal alternately, and is divided into segments. Each of the permanent magnets 21a has a sector shape. The inner and outer diameter arc centers are the same, but the tangent intersection of the circumferential end face is closer to the permanent magnet 21a, so that the wedge is tightened from the outer diameter side of the yoke 21b by screwing the permanent magnet 21a to the yoke. Signed to 21b. With this configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. The permanent magnet 21a is a neodymium (Nd—Fe—B) based magnet having a high energy product, and is coated with nickel to enhance corrosion resistance. The yoke 21b is made of a low-carbon steel having high magnetism, and is plated with nickel to improve wear resistance and corrosion resistance and prevent wear during bearing replacement after processing and molding.

[0329] The first outer rotor 21 has a surface for fitting and fixing the inner ring of the bearing 19 and the cylindrical member 23. The four-point contact ball bearing 19 is a very thin bearing, and its rotational accuracy and friction torque are greatly affected by differences in accuracy and linear expansion coefficient of the assembled parts. Therefore, in the case of the present embodiment, the inner ring of the bearing 19 which is a rotating ring is an interference fit or an intermediate fit to the yoke 21b which is easy to obtain processing accuracy and whose linear expansion coefficient is substantially the same as the bearing ring material of the bearing. The outer ring of the bearing 19, which is a fixed ring, is fitted to the austenitic stainless steel bearing holder or aluminum boss to prevent the bearing 19 from rotating and the friction torque from increasing due to temperature rise. ing.

[0330] A first stator 29 is disposed on the inner side in the radial direction of the partition wall 13 so as to face the inner peripheral surface of the first outer rotor 21. The first stator 29 is attached to a cylindrically deformed lower portion of a flange portion 12a extending in the radial direction at the center of the main body 12. The first stator 29 is formed of a laminated material of electromagnetic steel plates and is insulated from each salient pole. As a process, the motor coil is concentrated after the bobbin is fitted. The outer diameter of the first stator 29 is approximately the same as or smaller than the inner diameter of the partition wall 13.

[0331] The first inner rotor 30 is disposed on the radially inner side of the first stator 29. 1st inside The rotor 30 is rotatably supported by a ball bearing 33 with respect to a resolver holder 32 that is bolted to the outer peripheral surface of the main body 12. A permanent magnet 30a is attached to the outer peripheral surface of the first inner rotor 30 via a knock 30b. The permanent magnet 30a is composed of 32 poles in the same manner as the permanent magnet 21a of the first outer rotor 21, and 16 magnets of N poles and S poles are alternately made of magnetic metal. Accordingly, the first inner rotor 30 is rotated in synchronism with the first outer rotor 21 driven by the first stator 29.

[0332] The bearing 33 that rotatably supports the first inner rotor 30 is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, it is possible to reduce the thickness of the direct drive motor D1 because only one bearing is required. Since the interior of the partition wall 13 is an atmospheric environment, a bearing using grease lubrication based on general bearing steel and mineral oil can be applied.

[0333] Resolver rotors 34a and 34b are assembled as detectors for measuring the rotation angle on the inner periphery of the first inner rotor 30, and the resolver stator 35 is disposed on the outer periphery of the resolver holder 32 so as to be opposed thereto. In this embodiment, the high-resolution incremental resolver stator 35 and the absolute resolver stator 36 that can detect the position of the rotor in one rotation are arranged in two layers. /! For this reason, even when the power is turned on, the rotational angle of the absolute resolver rotor 34b is known, no return to origin is required, and the electrical phase angle of the magnet with respect to the coil increases, so the drive current of the direct drive motor D1 The rotation angle used for control can be detected without using a pole detection sensor.

[0334] The resolver holder 32 and the first inner rotor 30 are made of carbon steel, which is a magnetic material, so that electromagnetic noise from the motor field and motor coil is not transmitted to the resolver stators 35, 36 that are angle detectors. In addition, after processing and molding, it has been chromated to prevent fouling. The

The high-resolution variable reluctance resolver used in the present embodiment has an incremental resolver rotor 34a having a plurality of slot teeth having a constant pitch, and the outer peripheral surface of the incremental resolver stator 35. Are provided with teeth shifted in phase with respect to the incremental resolver rotor 34a at each magnetic pole parallel to the rotation axis, and a coil is wound around each magnetic pole. When the incremental resolver rotor 34a rotates together with the first inner rotor 30, the reluctance between the incremental resolver stator 35 and the magnetic pole changes, and the fundamental wave component of the change in reluctance becomes n cycles in one revolution of the incremental resolver rotor 34a. Thus, the change in reluctance is detected, digitalized by the resolver control circuit shown in FIG. 54, and used as a position signal, so that the rotational angle of the incremental resolver rotor 34a, that is, the first inner rotor 30 is (Or rotation speed) is detected. The resolver rotors 34a and 34b and the resolver stators 35 and 36 constitute a detector.

[0335] According to the present embodiment, the first inner rotor 30 rotates at the same speed by the magnetic coupling action with respect to the first outer rotor 21, that is, rotates with the first outer rotor 21, so that the first outer rotor 21 rotates. The corner can be detected through the bulkhead 13. Further, in the present embodiment, the resolver alone has the bearing 33 without using the parts forming the motor and the uzing, and therefore, the eccentricity adjustment with the resolver alone is performed before the resolver coil is assembled into the housing. Since accuracy adjustment such as position adjustment can be performed, there is no need to provide adjustment holes or notches on both flanges of the housing. In addition, the rotating wheel of the bearing device 19 that is rotatably supported by the first outer rotor 21 is fitted into a rotor yoke 21b that is easy to obtain machining accuracy and has the same linear expansion coefficient as the driving wheel of the bearing device 19. In addition, the rotation accuracy can be improved and the friction torque can be prevented from changing due to temperature changes.

Next, the force for explaining the direct drive motor D2 Here, the main body 12 constitutes a housing. The above-described cylindrical member 23 of the direct drive motor D1 extends upward to a position where it overlaps with the direct drive motor D2, and has a four-point contact ball bearing 19 ′ used in vacuum on its inner peripheral surface. The outer ring is fitted and fitted with bolts 20 '. On the other hand, the inner ring of the bearing 19 ′ is fitted to the outer periphery of the second outer rotor 21 ′, It is fixed by the bolt 22 '. Here, the bolt 22 'and the magnetic shield plate 41 extending inward in the radial direction are fastened together. The second outer rotor 21 ′ is rotatably supported with respect to the partition wall 13, and a ring-shaped member 23 ′ that supports the arm A2 (FIG. 52) is fixed by a bolt 24 ′. Further, the bolt 24 'fastens the magnetic shield plate 25 extending inward in the radial direction together with the ring-shaped member 23'.

[0337] The magnetic shield plates 41 and 25 'are subjected to nickel plating in order to enhance the anti-corrosion and corrosion resistance after press molding the SPCC steel plate, which is a magnetic material. The magnetic shield plates 41 and 25 are interposed between the first outer rotor 21 and the second outer rotor 21 to form a magnetic shield and prevent mutual rotation due to magnetic flux leakage from them. . That is, the magnetic shield plate 25 ′ is fastened to the yoke 21b ′ with the ring-shaped member 23 ′, which is a non-magnetic material, interposed therebetween, thereby preventing unnecessary magnetic circuits from being generated. Since the magnetic shield plates 41 and 25 can prevent magnetic interference between the rotors, it is possible to achieve a configuration in which the overall shaft length is suppressed while being a biaxial coaxial motor system. The magnetic shield plate 41 prevents foreign matter from being attracted from the outside.

[0338] The bearing 19 'is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, since the direct drive motor D2 requires only one bearing, the biaxial coaxial motor of the present invention can be made thinner. The inner and outer rings are made of martensitic stainless steel, which has high corrosion resistance and can be hardened by quenching. The rolling elements are ceramic balls, and the lubricant is vacuum grease that does not solidify even under vacuum.

[0339] The second outer rotor 21 'mechanically fastens the permanent magnet 21a', the annular yoke 21b 'made of a magnetic material to form a magnetic path, and the permanent magnet 21a' and the yoke 21b '. Non-magnetic for It is composed of a wedge (not shown) that is physically strong. Permanent magnet 21a 'is a segment type with a configuration of 32 poles, with 16 N-pole and S-pole magnets alternately made of magnetic metal and divided into poles, each of which has a sector shape. The center of the arc of the inner and outer diameters is the same force.By making the tangential intersection of the circumferential end faces closer to the permanent magnet 21a ', the wedge 21a' is tightened with a screw from the outer diameter side to tighten the permanent magnet 21a '. It is fastened to York 21b '. With such a configuration, the permanent magnet can be fastened without using a fixing member that generates outgas, such as an adhesive. Permanent magnet 21a 'is a high energy product neodymium (Nd-Fe-B) based magnet, which is coated with nickel to enhance corrosion resistance. Yoke 21b 'is made of low-carbon steel with high magnetic properties, and is plated with nickel to improve wear resistance and corrosion resistance after machining and to prevent wear during bearing replacement.

[0340] Further, the second outer rotor 21 'has a surface for fitting and fixing the inner ring of the bearing 19' and the ring-shaped member 23 '. The four-point contact ball bearing 19 'is a very thin bearing, and its rotational accuracy and friction torque are greatly affected by differences in the accuracy and linear expansion coefficient of the assembled parts. Therefore, in the case of the present embodiment, the inner ring of the bearing 19 ′ is tightly fitted or intermediately fitted to the yoke 21b, which is easy to obtain machining accuracy and has the same linear expansion coefficient as the bearing ring material of the bearing. The outer ring is made into a clearance fit with an austenitic stainless steel bearing holder or an aluminum boss, thereby preventing a decrease in rotational accuracy of the bearing 19 ′ and an increase in friction torque due to a temperature rise.

[0341] On the radially inner side of the partition wall 13, a second stator 29 'is disposed so as to face the inner peripheral surface of the second outer rotor 21'. The second stator 29 ′ is attached to the upper part of the flange 12 a that extends in the radial direction in the center of the main body 12, and is formed of a laminated material of electromagnetic steel sheets, and each salient pole is insulated. As shown, the motor coil is concentrated after the bobbin is fitted. The outer diameter of the second stator 29 ′ is approximately the same as or smaller than the inner diameter of the partition wall 13.

[0342] A second inner rotor 30 'is arranged inside the second stator 29' in the radial direction. The second inner rotor 30 ′ is rotatably supported by a ball bearing 33 ′ with respect to a resolver holder 32 ′ bolted to the outer peripheral surface of the main body 12. A permanent magnet 30a ′ is attached to the outer peripheral surface of the second inner rotor 30 ′ via a back yoke 30b ′. Permanent magnet 30a ' 2 As with the permanent magnet 21a 'of the outer rotor 21', it has a 32-pole configuration, and each of the 16 N-pole and S-pole magnets has a magnetic metal force alternately. Accordingly, the second inner rotor 30 ′ is rotationally driven by the second stator 29 ′ in synchronization with the second outer rotor 21 ′.

[0343] The bearing 33 'that rotatably supports the first inner rotor 30' is a four-point contact ball bearing that can load radial, axial, and moment loads with a single bearing. By using this type of bearing, only one bearing is required, so the direct drive motor D2 can be made thinner. Since the inside of the partition wall 13 is an atmospheric environment, a bearing using grease lubrication based on general bearing steel and mineral oil can be applied.

[0344] The resolver rotors 34a 'and 34b' are assembled as detectors for measuring the rotation angle on the inner periphery of the second inner rotor 30 ', and the outer periphery of the resolver holder 32' is opposed to it. In this embodiment, the resolution of the resolver stator 35 ', 36' is high resolution incremental resolver stator 35, and the absolute resolver stator 36 'that can detect the position of the rotor in one rotation. Are arranged in two layers. For this reason, even when the power is turned on, the rotational angle of the absolute resolver rotor 34b 'can be known, no return to origin is required, and the electrical phase angle of the magnet with respect to the coil is different, so the relative rotational angle of the direct drive motor D2 is This is possible without using a pole detection sensor.

[0345] The resolver holder 32 and the second inner rotor 30 are magnetic bodies so that electromagnetic noise from the motor field and the motor coil is not transmitted to the resolver stators 35 'and 36' that are angle detectors. Carbon steel is used as a material, and chromate plating is applied after processing to prevent fouling.

According to the present embodiment, the second inner rotor 30 'rotates at the same speed by the magnetic coupling action with respect to the second outer rotor 21'. The rotation angle can be detected through the partition wall 13. Further, in the present embodiment, the parts constituting the motor, the bearing 33 is provided as a single resolver without using uzing. Since it is possible to adjust the accuracy of the resolver coil position, etc., there is no need to provide adjustment holes or notches on both flanges of the housing. In addition, the rotating wheel of the bearing device 19 ′ that is rotatably supported by the second outer rotor 21 ′ is fitted to the rotor yoke 21 b ′, which is easy to obtain machining accuracy and whose linear expansion coefficient is substantially the same as the driving wheel of the bearing device 19 ′. By combining them, it is possible to improve the rotation accuracy and prevent the friction torque from fluctuating due to temperature changes.

In the high-resolution variable reluctance resolver used in the present embodiment, the incremental resolver rotor 34a ′ has a plurality of slot tooth rows having a constant pitch, and the outer circumference of the incremental resolver stator 35. The surface is provided with teeth that are shifted in phase with respect to the incremental resolver rotor 34a ′ at each magnetic pole parallel to the rotation axis, and a coil is wound around each magnetic pole. When the incremental resolver port 34a rotates together with the second inner rotor 30 ', the reluctance between the magnetic poles of the incremental resolver stator 35 changes, and the basic reluctance change occurs with one rotation of the incremental resolver rotor 34a. The reluctance change is detected so that the wave component has n cycles, is digitalized by the resolver control circuit shown in FIG. 54, and is used as a position signal, so that the incremental resolver rotor 34a ′, that is, the first 2The rotation angle (or rotation speed) of the inner rotor 30 'is detected. The resolver rotors 34a, 34b and the resolver stators 35, 36 constitute a detector.

[0347] According to the present embodiment, the magnetic shield plates 25 and 41 are arranged between the first outer rotor 21 and the second outer rotor 21 ', thereby suppressing mutual magnetic interference. However, it avoids malfunctions such as erroneous driving and rotation. In addition, the outer peripheral edge 12b of the flange portion 12a extending between the direct drive motors Dl and D2 in the main body 12 is made of carbon steel, which is a magnetic material, between the first stator 29 and the second stator 29 ′. In order to prevent the first outer rotor 21 or the second outer rotor 21 ′ from generating a thrust in the wrong rotation direction due to the influence of the leakage magnetic flux, the magnetic fields that shield each other's magnetic field are included. Functions as a shield.

[0348] The first stator 29 and the second stator 29 'are vertically arranged around the flange portion 12a. A resolver is arranged on the radially inner side. The main body 12 has a hollow structure, and the flange portion 12a has at least one radial through hole 12d communicating with the center through which the motor wiring is drawn out to the center of the main body 12. It has a structure. On the other hand, at least one notch 12e, 12e is provided at each end of the main body 12, and the resolver wiring is drawn out to the center of the main body 12 through these. With this structure, the direct motor D1 resolver, the stator 29, the direct motor D2 stator 29, and the resolver can be arranged in this order from the housing side. In addition, the angle of the stator and resolver can be adjusted. Therefore, if a separate facility for rotationally driving the reference outer rotor is prepared, the angle of the resolver relative to the stator can be adjusted with high accuracy by setting the main body 12 incorporating the stator and resolver in the facility. Therefore, it is possible to prevent the angle positioning accuracy from being lowered due to the deviation of the commutation, and to improve the compatibility of the drive control circuit with the two-axis coaxial motor of the present invention.

FIG. 55 is a block diagram showing a drive circuit for the direct drive motors Dl and D2. When a motor rotation command is also input to the external computer force, the motor control circuit DMC1 for the direct drive motor D1 and the motor control circuit DMC2 for the direct drive motor D2 are each sent from the CPU to the three-layer amplifier (AMP). The drive signal is output, and the drive current is supplied to the direct drive motors Dl and D2 with a three-layer amplifier (AMP) force. As a result, the outer rotors 21, 21 'of the direct drive motors Dl, D1 rotate independently to move the arms A1, A2 (Fig. 52). When the outer rotor 21, 21 'rotates, the resolver signal is output from the resolver stator 35, 36, 35, 36, which has detected the rotation angle as described above, and is output to the resolver digital converter (RDC). The CPU input after digital conversion judges whether or not the outer rotor 21, 21 'has reached the command position, and when it reaches the command position, it stops the drive signal to the 3-layer amplifier (AMP). Stop rotation of outer ports 21, 21 '. This enables servo control of the outer rotors 21, 21 '.

[0350] When driving multiple axes in a vacuum environment, if the current rotation position of arms A1 and A2 is not recognized when the power is turned on, the arm A1 or the like is attached to the wall of the vacuum chamber or the shatter of the vacuum chamber. In this embodiment, the absolute resolver stators 36 and 36 'that detect the absolute position of one rotation of the rotating shaft, and the incremental resolver stator 35 and that detect a rotational position with finer resolution are used in this embodiment. 35, a variable reluctance resolver is used, so that the rotational position of the outer rotors 21 and 21, that is, the arms Al and A2, can be controlled with high accuracy.

[0351] Here, since a force detector that employs a resolver for detecting the rotation of the inner rotor 30 can be disposed on the atmosphere side inside the partition wall 13, in general, a servo motor used for high-accuracy positioning is highly accurate and smooth. An optical encoder adopted as a position detecting means for driving, a magnetic encoder using a magnetoresistive element, or the like can also be used. FIG. 56 is a cross-sectional view showing a four-axis coaxial motor system that works on a modification of the present embodiment.

In the modification shown in FIG. 56, two sets of direct drive motors Dl and D2 (4 in total) are directly arranged. The individual direct drive motors have the same configuration as shown in FIG. The same reference numerals are given to the main parts, and the description is omitted.

In the present embodiment, partition wall holder 113a is airtightly coupled to upper disk portion 110 attached to the upper surface of main body 12 connected in series via O-ring OR, and the outer peripheral surface thereof. The upper end of thin cylinder 113b is TIG welded. The lower end of the thin-walled cylinder 113b is TIG welded to the holder 15 as in the above-described embodiment. The partition wall holder 113a, the thin cylinder 113b and the holder 15 constitute a partition wall. This is commonly used for the four direct drive motors.

[0353] The upper surface of the disc part 110 is closed by the lid member 101, and the bearing holder 107 attached to the outer periphery thereof supports the bearing 19. The disk part 110, the lid member 101, and the bearing holder 107 have high corrosion resistance! Use austenitic stainless steel as the material! /

The outer peripheral surface of the upper disk part 110 where the bearing holder 107 is attached is located radially inward of the thin cylinder 113b. Therefore, if the bearing holder 107 is removed from the upper disk part 110, the four outer rotors 21, 21 ′ can be removed upward without disassembling the upper disk part 110. Therefore, it is possible to facilitate work that does not require disassembly of the airtight structure during maintenance. [0354] In the present embodiment, the magnetic shield plates 25 'and 25' are arranged between the second outer rotors 21 and 21 at the center, so that mutual magnetic interference is suppressed. This avoids malfunctions such as erroneous driving and companionship. Between the main bodies 12 and 12, a magnetic shield plate 125 whose outer peripheral force extends in the radial direction to the inside of the thin cylinder 113b is disposed. The magnetic shield plate 125 is made of carbon steel, which is a magnetic material, and is interposed between the second stators 29 ′ and 29 ′, so that the adjacent second outer rotor 21 ′ is affected by the leakage magnetic flux. , 21 'functions as a magnetic shield that shields the magnetic field of each other so as not to generate a thrust in the wrong rotation direction. In this way, coupled with the effects of the other magnetic shields 25, 41, and 12b, it is possible to achieve a configuration in which the overall axial length is suppressed while being 4-axis coaxial.

[0356] The rotor permanent magnet is a neodymium (Nd-Fe-B) -based magnet, and nickel coating is used as an example of coating to improve corrosion resistance. This material is not limited to the surface treatment, and it is changed as appropriate depending on the environment in which it is used. System magnets should be used, and if used in ultra-vacuum, a titanium nitride coating with a high outgas barrier should be applied.

[0357] In addition, the yoke is made of low-carbon steel and has been explained using an example of nickel plating. 1S This material is suitable depending on the environment in which the material is used and not limited to surface treatment. Especially for surface treatment, if it is used in ultra-vacuum, it should be subjected to force-less plating with a small number of pinholes, clean soldering, titanium nitride coating, etc.

[0358] Also, bearings 19 and 19 'have been described using an example of grease lubricated four-point contact ball bearings for vacuum, but this is not limited to this type, material, and lubrication method. It can be changed as appropriate depending on conditions, rotational speed, etc., and it can be a cross roller bearing. In the case of a 4-axis coaxial motor, it can be supported by another bearing to further increase mechanical rigidity. If a multi-point contact bearing cannot be used, such as when rotating at high speeds, a bearing that supports the rotor of each shaft and another bearing may be configured to apply preload as deep groove ball bearings or angular bearings. When used in an ultra-vacuum, it is possible to use a metal-lubricated material that does not emit gas, such as a metal ring plated with a soft metal such as gold or silver.

[0359] Further, although the inner rotor functioning as a magnetic coupling has been described in the form of using a permanent magnet and a back yoke, the material and shape of the permanent magnet and the back yoke are not limited to this. For example, depending on the mass of the resolver and the friction torque of the bearing, the number of poles may not be the same as that of the outer rotor, or the width may not be the same. A salient pole that does not use a permanent magnet is also acceptable.

[0360] In addition, an example in which grease lubrication four-point contact ball bearings are used as the bearings 33 and 33 'that rotatably support the rotation side of the angle detector has been described, but this type and the lubrication method are limited. However, if the multi-point contact bearing cannot be used, such as high-speed rotation or reduction of friction torque, an anguilla bearing is a deep groove ball bearing. A structure may be used in which two are arranged for each axis to apply preload. In addition, the material, shape, and manufacturing method of the structural parts and partition walls arranged in and out of the other partition walls are appropriately changed depending on the manufacturing cost, the environment used, the load conditions, the configuration, and the like.

[0361] In the motor system described above, the thrust in the rotational direction is applied to the magnetic force coupling used for each rotor and rotation detector by the magnetic flux that also leaks the magnetic coupling force used for the rotor, stator, and resolver of each axis. Thus, magnetic shields for shielding each other's magnetic field are arranged between the rotors of each axis, or the electromagnetic fields generated by the rotor, stator and resolver force of each axis In order not to interfere with the resolver, a magnetic shield is provided to shield each other's electromagnetic field, or the number of rotor poles and the number of stator slots in the axially adjacent axes are changed. As a result, magnetic interference generated between the axes is prevented, so that the axial length of each axis and the axial distance of each axis can be shortened. Therefore, although it is a multi-axis coaxial motor system such as 2-axis coaxial or 4-axis coaxial, a configuration in which the overall axial length is suppressed is possible. In particular, in a system using a multi-axis direct drive motor such as a 4-axis coaxial system, two frog redder arm robots that can be positioned with high accuracy without greatly changing the chamber structure can be installed. Performance and availability can be increased.

[0362] While the present invention has been described with reference to the embodiments, it should be understood that the present invention should not be construed as being limited to the above-described embodiments, and that modifications and improvements can be made as appropriate. The For example, the direct drive motor of the present embodiment can be used not only in a vacuum atmosphere but also in an atmosphere outside the atmosphere. For example, in the case of a semiconductor manufacturing process, reactive gas for etching may be introduced into the vacuum chamber after evacuation, but in the direct drive motor of this embodiment, the inside and outside are shielded by the partition walls. Therefore, there is no possibility that the motor coil or the insulating material will be etched.

Claims

The scope of the claims

[1] In a motor having at least a main rotor and a stator,

The main rotor is attached to the inner peripheral surface of the yoke disposed between the adjacent magnetic poles, an annular yoke having magnetic force, a plurality of magnetic poles made of permanent magnets arranged on the inner peripheral surface of the yoke, and Including spacers,

The minimum distance in the circumferential direction between a pair of opposing surfaces of the adjacent magnetic poles is smaller than the maximum width in the circumferential direction of the spacer, and the minimum gap between the opposing surfaces of the magnetic poles is: A motor, characterized in that the motor is located radially outward from the maximum width portion of the spacer.

[2] The motor according to claim 1, wherein a gap is formed between an opposing surface of the magnetic pole and the spacer.

3. The motor according to claim 1, wherein the yoke has an abutting portion that abuts on the magnetic pole when the magnetic pole is displaced in the axial direction.

4. The direct drive motor according to claim 1 or 2, wherein the spacer has a contact portion that contacts the magnetic pole when the magnetic pole is displaced in the axial direction.

[5] The motor according to any one of [1] to [4], wherein the spacer is fixed to the yoke by a bolt that also has a non-magnetic force.

[6] The motor is a direct drive motor that directly drives the rotor without using a reduction gear or the like. The motor is used in an atmosphere outside the atmosphere. The housing extends the housing force, and the atmosphere side and the atmosphere outside. And a partition wall that isolates

6. The apparatus according to claim 1, further comprising: a sub-porter disposed on the atmosphere side with respect to the partition wall and rotated together with the main rotor; and a detector for detecting a rotation speed of the sub-rotor. A motor according to any one of the above.