JP2000032701A - Hermetic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite hermetic actuator whose length is suppressed and which enables space saving of the device as a whole. SOLUTION: Hermetic actuators which are respectively composed of motor rotors 16A and 16B which have rotor poles 15A and 15B and are connected to respective output shafts A and B driven rotate individually, motor stators 14A and 14B which are provided so as to face the motor rotors 16A and 16B and have stator poles 13A and 13B excited by rotation driving coils 12A and 12B, a housing 11 in which the motor stator are housed so as to be airtightly separated from the inside of a chamber, sealing partitions 28A and 28B which are made of nonmagnetic metal and placed between the corresponding motor rotors and motor stators, and measuring means 21A and 21B by which displacements of the motor rotors are measured are used as unit hermetic actuators 10A and 10B which are coaxially arranged in parallel with each other at positions radially different from each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a closed type actuator, and more particularly, to a magnetic pole or a coil of a motor which is corroded in an ultra-high vacuum atmosphere in which a trace amount of contaminants or impurity gases is not allowed or in a corrosive gas atmosphere. The present invention relates to a closed-type actuator suitable for use in an environment in which the actuator is closed.

[0002]

2. Description of the Related Art For example, in a semiconductor manufacturing apparatus and the like, a work on a workpiece is performed in an ultra-high vacuum atmosphere in order to remove impurities as much as possible. An actuator for rotating an output shaft for positioning and transporting is required for a workpiece positioning device and a transporting device used in that case. As a conventional actuator of this type, for example, a closed-type actuator previously proposed by the present applicant and capable of high-precision positioning without releasing an impurity gas in an ultra-high vacuum atmosphere (Japanese Patent Laid-Open No. 3-150041)
And JP-A-3-150042). This motor includes a motor stator having a rotation driving magnetic pole that is excited by a rotation driving coil, and a rolling bearing that is disposed facing the magnetic pole surface of the motor stator with a slight clearance therebetween. A motor rotor rotatably supported via the motor rotor; and a resolver serving as displacement detection means for measuring the displacement of the motor rotor. A non-magnetic metal partition is disposed in a gap between the motor stator and the motor rotor to hermetically surround the internal space in which the motor stator is disposed, thereby isolating the internal space from the motor rotor side space. With this actuator placed outside the vacuum chamber, a rotational force is applied to an output shaft protruding into the vacuum chamber.

As described above, since the motor stator and the motor rotor are separated from each other by the non-magnetic metal partition walls, even when used in a high vacuum atmosphere or a reactive gas atmosphere of the semiconductor manufacturing apparatus, the coil of the actuator or the organic insulating material can be used. Does not release impurity gas from the atmosphere and contaminate the atmosphere or erode the coils and the organic insulating material. Further, the formation of the magnetic circuit between the motor stator and the motor rotor is not hindered, and furthermore, the resolver is used. This is extremely useful in practical use, such as realizing accurate positioning.

Further, Japanese Patent Publication No. Hei 8-5067671 discloses a biaxially coaxial rotary drive actuator for a transfer device in a vacuum chamber. This one is
As shown in FIG. 5, a mounting flange 201 is mounted on the opening of the bottom wall 202 of the vacuum chamber, and inside the housings 216 and 236 located outside the vacuum chamber, an outer drive shaft 204 and an inner drive shaft 205 are provided. Are arranged coaxially and extend out of the housing through the opening. The outer drive shaft 204 located in the vacuum chamber is supported by a bearing 206 at the tip of the inner drive shaft 205.

A motor rotor 207 is mounted on the outer surface of the outer drive shaft 204, and a corresponding motor stator 208 is supported by a housing 216 outside the motor rotor 207. Similarly, the inner drive shaft 205
A motor rotor 209 is attached to the outer surface of the motor rotor 209, and a corresponding motor stator 210 is supported by a housing 236 outside the motor rotor 209.

The outer drive shaft 204 is supported by the housing 216 by bearings 218 and 219, and the inner drive shaft 205 is supported by the housing 236 by bearings 238 and 239. Between the motor rotor 207 and the motor stator 208, and between the motor rotor 209 and the motor stator 210
A thin nonmetallic partition wall 216a, 236a extending from the housing 216 and the housing 236 is interposed therebetween, and separates the motor rotors 207, 209 to the vacuum side and the motor stators 208, 210 to the atmosphere side. Impurity gas released from the motor stator coil is prevented from contaminating the inside of the vacuum chamber. The motor rotor 20
7 (209), for example, a disk 211 (231) having an optical slit is provided on the motor rotor 207 (209), and the light emitting element 213 (233) and the light receiving element 214 (234) are provided on the motor stator side. )
Is provided with an optical detection mechanism.

As is apparent from the configuration shown in FIG. 5, this biaxial rotary driving actuator has two actuators connected in series.
Japanese Patent No. 38438 discloses a biaxial coaxial rotary drive actuator shown in FIG. 6 proposed by the present applicant. Here, the motor stator 311 on which the rotation driving magnetic pole 315 is formed, and the magnetic pole face of the motor stator 311 are supported via rolling bearings 317 and 318 which are disposed facing each other with a slight gap therebetween. Motor rotor 3
12 and a variable reluctance type resolver 326 for measuring the displacement of the motor rotor 312.
A sealing wall 333 made of a non-magnetic metal is disposed in a gap between the motor rotor 312 and the motor rotor 312 to hermetically cover the internal space in which the motor stator 311 is disposed, and the bearings 317 and 318 are disposed in the axial direction of the sealing wall 333. A sealed actuator arranged on both sides and configured to directly receive a load acting on the bearing by the housing is used as a unit actuator. And 2
The two unit actuators are connected in series to form a biaxial coaxial actuator unit having two output shafts A and B coaxially. As described above, the necessity and effect of the composite type actuator in which a plurality of unit actuators are coaxially connected are described in JP-A-9-2384.
No. 38, items [0067] to [0070] are described in detail, and redundant description is omitted. In short, by combining the output shaft coaxially, the mounting opening in the vacuum chamber is minimized, And it can be said that it is extremely effective in minimizing the surface area in the vacuum chamber. On the other hand, the actuator itself has the advantage that many components can be shared, and the cost of component production can be reduced and maintenance can be facilitated.

[0008]

However, in the above-mentioned conventional composite type actuator, since the unit actuators are arranged in series in the axial direction, there is a problem that the total length of the actuator becomes long. In recent years, there has been a tendency to increase the need to drive larger objects, and if the torque is increased to cope with this, the outer diameter and overall length of the actuator must be increased.

Accordingly, the present invention has been made in view of such problems of the conventional composite type actuator, and has a composite type closed type that can reduce the length and save the space of the entire apparatus. It is an object to provide an actuator.

[0010]

In order to achieve the above object, the invention according to claim 1 of the present invention is directed to a hermetically sealed type having a plurality of output shafts coaxially driven independently of each other in a chamber. An actuator, comprising: a motor rotor having rotor magnetic poles connected to each of the plurality of output shafts; and a motor driven rotor disposed at a distance from a magnetic pole surface of the motor rotor so as to be opposed to each other and excited by a rotation driving coil. A motor stator having stator poles, a housing in which the motor stator is air-tightly separated from the chamber, a bearing for rotatably supporting a rotation shaft of the motor rotor in the housing, and a motor rotor and a motor stator opposed to each other. And a sealing partition made of a non-magnetic metal material and a displacement measuring means for measuring a displacement of the motor rotor A sealed actuator closable actuator unit is composed of a plurality units of sealed actuator of the unit, respectively, characterized by being configured in parallel concentrically different position in the radial direction.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. The hermetically-sealed actuator 10 shown in FIG. 1 is independently rotatably driven in a double-cylindrical housing 11 having two large-diameter and small-diameter cylindrical bodies 11A and 11B hermetically connected by a bottom plate 11C and having an open top. Two output shafts, namely, a first output shaft A and a second output shaft B are coaxially arranged. In other words, a sealed actuator 10A having a unit having the first output shaft A and a sealed actuator 10B having the second output shaft B are connected in parallel on two axes coaxially and at different positions in the radial direction. One unit of the sealed actuator 10A is disposed outside, and the other unit of the sealed actuator 10B is concentrically disposed inside.

First, the structure of the hermetically sealed actuator 10A disposed outside will be described. The actuator 10A is a so-called inner rotor type variable reluctance step motor. That is, a plurality of motor stator magnetic poles 13A as rotation driving magnetic poles excited by the rotation driving coil 12A are arranged and fixed on the inner circumferential surface of the outer wall 11A of the double cylindrical housing 11 at equal circumferential intervals. ing. On the inner circumference of each motor stator pole 13A, a plurality of teeth having a constant pitch are provided in parallel with the rotation axis of the first output shaft A. These teeth have a known configuration called salient pole teeth in a step motor, and are also referred to as salient pole teeth in the following description. By winding a rotation drive coil 12A around each motor stator magnetic pole 13A via an insulating material, a motor stator 14A of the unitary sealed actuator 10A is configured.

On the other hand, a motor rotor magnetic pole 15A made of a magnetic metal is disposed opposite to the inner peripheral surface of the motor stator 14A with a slight air gap therebetween. To form a motor rotor 16A of the unitary sealed actuator 10A.

A row of teeth is provided on the outer peripheral surface of the motor rotor magnetic pole 15A in parallel with salient pole teeth on the inner peripheral surface of the motor stator magnetic pole 13A. The pitch of the tooth row is the same as the pitch of the teeth of the motor stator magnetic pole 13A, but the salient pole teeth of the motor stator magnetic pole 13A and the tooth row of the magnetic pole of the motor rotor magnetic pole 15A are arranged so as to be relatively shifted in phase. I have. Thus, by sequentially energizing the teeth of the motor stator magnetic pole 13A in the circumferential direction while controlling the supply of current to the rotation drive coil 12A, the tooth rows of the motor rotor magnetic pole 15A are sequentially attracted to form the motor rotor 16A. 1
The output shaft A is rotated inside the motor stator 14A.

The first output shaft A constituting the motor rotor 16A is spaced apart in the axial direction from the motor stator 14A.
It is rotatably supported on the housing outer wall 11A via vacuum rolling bearings 17A and 18A coaxially arranged. Each of the above-mentioned vacuum rolling bearings 17A and 18A uses a metal lubrication without gas release by plating a soft metal such as gold or silver on an inner ring and an outer ring.
The upper end of the first output shaft A protrudes outside the opening of the outer wall 11A of the housing 11, and a bolt hole 19A for fixing the driven body is provided on the end face. Reference numeral 20A denotes a preload setting spring for applying a preload to the lower vacuum rolling bearing 18A.

The displacement detector for detecting the relative displacement between the motor stator 14A and the motor rotor 16A in a space located on the upper end side of the motor stator magnetic pole 13A with high precision, as a rotation detector of high resolution. The variable reluctance type resolver 21A is incorporated therein. The resolver stator 23A having the resolver coil 22A is fixed to the inner peripheral surface of the housing outer wall 11A. On the other hand, the resolver rotor 24A is opposed to the resolver stator 23A and has a first output shaft A.
Is fixed to the step 25A. A plurality of salient pole teeth having a fixed pitch are provided on the inner peripheral surface of the magnetic pole of the resolver stator 23A of the variable reactance type resolver 21A, similarly to the motor stator magnetic pole 13A, and the resolver coil 22A is formed of the resolver stator 23A. It is wound around each magnetic pole. On the other hand, the resolver rotor 24A has, like the motor rotor magnetic pole 15A, a tooth row having the same pitch but shifted in phase. Then, with the rotation of the motor rotor 16A, the resolver rotor 24A rotates and the reluctance between the magnetic pole of the resolver stator 23A changes,
The fundamental wave component of the reluctance change is made to have n periods in one rotation of the resolver rotor 24A, and the reluctance change is detected and digitized by the resolver control circuit.
The rotation angle position (or rotation speed) of the first output shaft A constituting the motor rotor 16A by using it as a position signal
Is to be detected. Reference numeral 26A is a magnetic shield plate interposed between the motor stator magnetic pole 13A and the resolver 21A and fixed to the motor stator 14A.

For example, a non-magnetic stainless steel SUS304 is provided in a gap (air gap) between opposing surfaces of the motor stator magnetic pole 13A and the motor rotor magnetic pole 15A and a gap (air gap) between the opposing surfaces of the resolver stator 23A and the resolver rotor 24A. A cylindrical partition 28A made of a non-magnetic metal such as a non-magnetic metal is provided. The upper and lower ends of the partition wall 28A are subjected to electron beam welding and laser beam welding, respectively, so that the upper and lower vacuum rolling bearings 17A and 18A are provided.
Is hermetically welded to the inner peripheral surface of the housing outer wall 11A. Accordingly, the space in which the magnetic pole 13A of the motor stator 14A, the rotation driving coil 12A, the resolver stator 23A, the resolver coil 22A, and the like are housed is sealed in the housing outer wall 11A, and the space on the motor rotor 16A and the resolver rotor 24A side. (To be in a vacuum state as will be described later).

In this connection, for example, a molding agent is injected without gap into a space in which the motor stator 14A partitioned by the partition wall 28A, the rotation driving coil 12A, the resolver stator 23A, the resolver coil 22A and the like are stored. The partition wall 28A can be reinforced. A vacuum flange portion 11F is attached to the upper end side of the outer wall 11A of the housing 11, and constitutes a portion for attaching the hermetically sealed actuator 10 to a vacuum device.

Here, the variable reluctance resolver described above
21A will be described. As this resolver,
For example, Japanese Patent Application Laid-Open No. 5-122A916
And Japanese Unexamined Patent Publication No. Hei 8-506771 are preferred.
Appropriately available. This resolver is a resolver stator 2
3A, a first magnetic pole A having three phases and 18 poles as shown in FIG. ₁₁
~ A₁₆, B₁₁~ B₁₆, C₁₁~ C₁₆Are formed at predetermined intervals
And a second magnetic pole having three phases and 18 poles at an intermediate position of the first magnetic pole.
Pole A_{twenty one}~ A₂₆, B_{twenty one}~ B₂₆, C_{twenty one}~ C₂₆Are formed at predetermined intervals
And each pole is A₁₁─C_{twenty one}─B₁₁─A_{twenty one}─C₁₁─B_{twenty one}
─A₁₂─C_{twenty two}Are arranged in the order of ─. Each magnetic pole A
₁₁~ C₂₆Has three teeth T on the inner peripheral side end face._S1, T_S2,
T_S3Is formed and one excitation winding L is provided at the center._A11
~ L_C26Is wound. Therefore, the position of 180 °
Are in phase with each other. Also, the resolver rotor 24
Is the tooth T of the resolver stator 23A._S1~ T_S3Out of phase with
And the same pitch tooth row T_Rhave.

FIG. 3 shows a configuration of the resolver control circuit. One end of each of the exciting windings L _{A11 to} L _C26 is connected to a single-phase AC power supply 30 and the other end is connected through resistors R _{A1 to} R _C2. By grounding, the teeth T _{R of the} resolver rotor 24 are output from the output terminals T _{A1 to} T _C2 derived from between the excitation winding and the resistor.
I-phase output signals f _a1 (θ) to f _c1 (θ) and f _a2 (θ) based on a current change corresponding to a reluctance change between
f _c2 (θ) is output to terminals T _{A1 to} T _C1 and T _{A2 to} T _C2 , and is input to differential amplifiers 31A to 31C. The differential amplifiers 31A to 31C calculate the difference value, and the output is converted into a two-phase signal by the phase conversion circuit 32, and the two-phase signal f _c (θ),
f _s (θ) is supplied to the signal processing circuit 33.

The signal processing circuit 33 includes a multiplier and a synchronous rectifier to which an AC voltage is input as a synchronous signal from an AC power supply for excitation. The output signal of the synchronous rectifier is output as a speed signal, and the rotational speed is reduced. The digital value shown is output. For details of the resolver and the resolver control circuit,
Reference may be made to JP-A-5-122A916.

Next, a description will be given of the structure of the hermetically sealed actuator 10B disposed inside. The actuator 10B is a so-called outer rotor type variable reluctance step motor. Motor stator magnetic pole 13B excited by rotation drive coil 12B
Are fixed to the outer peripheral surface of the inner wall 11B of the double cylindrical housing 11. Each motor stator pole 13
A plurality of salient pole teeth having a constant pitch are provided on the outer circumference of B in parallel with the rotation axis of the second output shaft B. By winding a rotation drive coil 12B around each motor stator magnetic pole 13B via an insulating material, a motor stator 14B of the unitary sealed actuator 10B is formed.

On the other hand, a motor rotor magnetic pole 15B made of a magnetic metal is disposed to face the outer peripheral surface of the motor stator 14B with a slight air gap, and this is disposed on the inner peripheral surface of the second output shaft B. The motor rotor 16B of the unitary closed-type actuator 10B is integrally fixed to a surface. On the inner peripheral surface of the motor rotor magnetic pole 15B, a tooth row is provided in parallel with the salient pole teeth on the outer peripheral surface of the motor stator magnetic pole 13B. The pitch of the tooth row is the same as the pitch of the teeth of the motor stator magnetic pole 13B, but the phases of the salient pole teeth of the motor stator magnetic pole 13B and the tooth row of the motor rotor magnetic pole 15B are relatively shifted. Thus, the teeth of the motor rotor magnetic poles 15B are sequentially attracted by sequentially exciting the teeth of the motor stator magnetic poles 13B in the circumferential direction while controlling the current supply to the rotation drive coil 12B, and the second motor rotor 16B as the motor rotor 16B is sequentially attracted. Output shaft B
Is rotated outside the motor stator 14B.

The second output shaft B constituting the motor rotor 16B is spaced apart in the axial direction from the motor stator 14B.
It is rotatably supported on the housing outer wall 11B via vacuum rolling bearings 17B and 18B coaxially arranged. The upper end of the second output shaft B penetrates through the hollow hole of the first output shaft A and projects outside the opening of the outer wall 11A of the housing 11, and is used for fixing the driven body to the end face. A bolt hole 19B is provided. Reference numeral 20B denotes a preload setting spring for applying a preload to the lower vacuum rolling bearing 18B.

In a space located on the upper end side of the motor stator magnetic pole 13B, displacement detecting means for detecting a relative displacement between the motor stator 14B and the motor rotor 16B is provided.
A variable reluctance resolver 21B as a high-resolution rotation detector is incorporated. The resolver stator 23B having the resolver coil 22B is connected to the housing inner wall 11.
B is fixed to the outer peripheral surface. On the other hand, the resolver rotor 24B is fixed to the step 25B of the second output shaft B so as to face the resolver stator 23B. A plurality of salient pole teeth having a fixed pitch are provided on the outer peripheral surface of the magnetic pole of the resolver stator 23B of the variable reactance type resolver 21B, similarly to the motor stator magnetic pole 13B, and the resolver coil 22B is connected to the resolver stator 23B.
B is wound around the magnetic pole. On the other hand, the resolver rotor 24
B has tooth rows of the same pitch, shifted in phase, like the motor rotor magnetic pole 15B. A magnetic shield plate 26B is interposed between the motor stator magnetic pole 13B and the resolver 21B located above the magnetic pole 13B.

For example, a non-magnetic stainless steel SUS304 is provided in the gap between the opposing surfaces of the motor stator magnetic pole 13B and the motor rotor magnetic pole 15B (air gap) and between the opposing surfaces of the resolver stator 23B and the resolver rotor 24B (air gap). A cylindrical partition 28B made of a non-magnetic metal such as a non-magnetic metal is provided. The upper and lower ends of the partition wall 28B are respectively subjected to electron beam welding and laser beam welding to form the upper and lower vacuum rolling bearings 17B and 18B.
Is hermetically welded to the outer peripheral surface of the housing inner wall 11B. Thereby, the space in which the magnetic pole 13B of the motor stator 14B, the rotation driving coil 12B, the resolver stator 23B, the resolver coil 22B and the like are housed is sealed, and the space on the motor rotor 16B and the resolver rotor 24B side (vacuum state as will be described later). ) Are completely airtight.

In this connection, for example, a molding agent is injected without gap into a space in which the motor stator 14B, the rotation driving coil 12B, the resolver stator 23B, the resolver coil 22B and the like partitioned by the partition wall 28B are stored. The partition wall 28B can be reinforced. The upper end side of the cylindrical inner wall 11B of the housing 11B is closed, and only the lower end side is open.

Next, the operation of the closed type actuator 10 will be described. This composite hermetic actuator 10 is
For example, it is attached to an actuator attachment opening of a vacuum chamber. In this case, the tips of the first output shaft A and the second output shaft B are inserted into the vacuum chamber. An actuator 10A for driving these two axes,
10B are installed concentrically in parallel at different positions in the radial direction from each other, so that the overall length of the actuator 10 can be reduced to approximately half as compared with the case where both actuators are connected in series, and the entire device can be saved. Space can be realized.

This composite type closed actuator 1
0, a variable reluctance type step motor is used for each of the outer actuator 10A and the inner actuator 10B.
A and 16B do not generate heat due to overcurrent unlike an induction motor, and the motor rotors 16A and 16B are made of magnetic material having salient pole teeth without using a permanent magnet which is porous and easily absorbs gas. The arrival time is short.

Further, in this composite type sealed actuator 10, the motor stator 14A and the resolver stator 23A of the outer actuator 10A are separated from the inside of the vacuum chamber by a partition wall 28A, and the motor stator of the inner actuator 10B is separated. 14B and the resolver stator 23B are separated from the inside of the vacuum chamber by a partition wall 28B, so that the rotation driving coils 12A and 12B of the motor stator and the resolver coils 22A and 22B are separated.
There is no danger that the gas or moisture stored in the insulating material or the like will diffuse into the vacuum chamber and contaminate the vacuum atmosphere. Accordingly, the inside of the vacuum chamber can be easily evacuated, and a predetermined ultra-high vacuum can be reached in a short time even during bakeout, so that the production efficiency is high.
Also, there is no need to use an expensive inorganic material for the coil insulating material.

Further, in the case of manufacturing a semiconductor, the reactive gas for etching introduced into the vacuum chamber V after evacuation is protected by the partition walls 28A and 28B made of stainless steel. There is no possibility that the insulating material or the like is etched. The rotation drive coil 12
Since A and 12B are on the atmosphere side, it is easy to forcibly cool the interior of motor stators 14A and 14B by passing air or water as needed.

Also, the positioning accuracy of the rotation of the motor rotors 16A and 16B is ensured to be extremely high by feedback control. Now, each motor stator 1
When a current is applied to the rotary drive coils 12A, 12B of the motor stators 4A, 14B, a magnetomotive force is generated, and the motor stator magnetic poles 13A, 13B are generated.
The salient pole teeth of B are excited. In this case, since the thickness of the partition walls 28A and 28B made of non-magnetic metal is sufficiently small, the magnetic flux reaches the motor rotors 16A and 16B through the partition walls 28A and 28B. A magnetic circuit is formed between the energized motor stator magnetic poles 13A, 13B and the opposing motor rotor magnetic poles 15A, 15B, and the opposing teeth of both magnetic poles strongly attract each other.

That is, a motor current controlled via a drive unit (not shown) is sequentially supplied to each of the plurality of rotary drive coils 12A and 12B arranged in order along the circumferential direction in accordance with the arrangement. Excitation of each tooth of the motor stator magnetic poles 13A, 13B is sequentially moved according to the order of energization, and the respective motor rotors 16A, 16B rotate. Accordingly, the resolver rotors 24A and 24B of the resolvers 21A and 21B also rotate. The resulting reluctance change between the teeth of the resolver stators 23A and 23B is digitized by a resolver control circuit of a drive unit (not shown), and is used as a position signal, so that the motor rotor 16A of each of the unit actuators 10A and 10B can be used. Precise feedback control of the rotation angle of 16B is performed, and highly accurate positioning can be performed.

In this embodiment, the variable reluctance resolvers 21A and 21B are used as displacement measuring means for the motor rotors 16A and 16B. However, the present invention is not limited to this, and is generally used in servomotors used for high-precision positioning. An optical encoder, a magnetic encoder, or the like to be used can also be used. However, when it is assumed that the optical encoder is used in an ultra-high vacuum as in the present embodiment, an optical encoder or a magnetic encoder is not preferable. The reason is that the light emitting element, the light receiving element, the magnetoresistive element, and the like used therein are semiconductors, so that high-temperature bakeout at 100 ° C. or higher, which is generally performed as pretreatment in a vacuum chamber, is difficult, and This is because impurities contained in an insulating resin, a printed circuit board, and the like, which are required to prevent a short circuit when the circuit is used in a vacuum, may contaminate the vacuum environment.

In this embodiment, the magnetic shield plates 26A, 26B are provided between the variable reluctance resolvers 21A, 21B and the motor actuators 10A, 10B.
Are respectively interposed, but each actuator 1
The first output shaft A to which the motor rotor magnetic poles 15A, 15B of 0A and 10B and the resolver rotors 24A, 24B are attached.
The material of the second output shaft B may be a non-magnetic material. This makes it difficult to control the magnetism generated by the motor stack around the resolver with a normal resolver, but can cancel out the magnetism flowing from the motor stack and achieve more stable control. Become. That is, the partition wall 2 made of a non-magnetic metal that blocks between the resolver stators 23A and 23B and the resolver rotors 24A and 24B.
8A and 28B, the high frequency magnetic flux of the switching frequency of the motor current supplied from the motor driving power supply of the actuator and the leakage magnetic flux from the rotating magnetic field generated from the motor stator are mixed into the resolver to lower the S / N ratio. If there is a possibility of adversely affecting the high-accuracy position detection, if the first output shaft A and the second output shaft B, which are the mounting members of the resolver rotors 24A and 24B, are made of a non-magnetic material, the leakage magnetic flux is reduced. Mixing into the resolver rotors 24A and 24B via the output shaft can be suppressed,
By improving the S / N ratio, highly accurate position detection becomes possible.

Generally, the variable reluctance resolver is
Apply AC voltage to the resolver coil for detection to excite,
A reluctance change according to the rotational position θ of the slot teeth of the opposed resolver rotor is detected as an inductance change. The output Vsin θ from which the excitation voltage component has been removed by the synchronous rectifier can be detected, and the rotational position of the rotor can be detected. Can be detected. However, when partition walls 28A and 28B made of non-magnetic metal are provided to cut off between the stator and the rotor as in the present embodiment, if the frequency of the AC voltage for exciting the detection coil is high, the sealing is not performed. The eddy current in the non-magnetic metal generated when the magnetic flux penetrates the partition walls 28A and 28B increases, and it may be difficult to detect the rotational position of the rotor. In this case, if an alternating current of about 1 to 10 KHz is applied to excite the partition wall 28A for sealing,
The generation of the eddy current in 28B is suppressed, and the stable drive control of the rotor becomes possible.

In order to improve the S / N ratio, the windings 22A of the resolver stators 23A and 23B constituting the variable reluctance type resolver have been proposed by the present applicant in Japanese Patent Application Laid-Open No. 9-238438. , 22B as a differential circuit type to reduce noise.

FIG. 4 shows another embodiment of the present invention. Note that the same or corresponding parts as those in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. This differs from the sealed actuator 10 of the first embodiment in that the drive motor for the first output shaft A in the closed-type actuator 10 has an outer rotor structure instead of an inner rotor structure. That is, as shown in FIG. 4, a sealed actuator 10A having a first output shaft A and a sealed actuator 10B having a second output shaft B are coaxially arranged in two axes coaxially and at different positions in the radial direction. The configuration of the connection is the same as that of the first embodiment, except that the sealed actuator 10A of the unit disposed outside is replaced with an inner rotor type variable reluctance type step motor, and an outer rotor type It consists of a variable reluctance step motor.

The housing 11 further includes a cylindrical intermediate partition 11D at an intermediate position between the outer wall 11A, which is a large-diameter cylindrical body, and the inner wall 11B, which is a small-diameter cylindrical body. A plurality of motor stator magnetic poles 13A as rotation driving magnetic poles of the closed unit actuator 10A on the outer unit are arranged and fixed on the outer peripheral surface of the intermediate partition 11D at equal circumferential intervals. The salient pole teeth of each of the motor stator magnetic poles 13A are provided on a cylindrical outer peripheral surface. A rotation drive coil 12A is wound around each of the motor stator magnetic poles 13A via an insulating material to form a motor stator 14A of a unitary sealed actuator 10A. On the other hand, a motor rotor magnetic pole 15A made of a magnetic metal and disposed to face the outer circumferential surface of the motor stator 14A with a slight air gap is integrally fixed to the inner circumferential surface of the first output shaft A. Thus, the motor rotor 16A of the unitary sealed actuator 10A is configured.

A tooth row is provided on the inner peripheral surface of the motor rotor magnetic pole 15A in parallel with salient pole teeth on the outer peripheral surface of the motor stator magnetic pole 13A. The pitch of the tooth row is the same as the pitch of the teeth of the motor stator magnetic pole 13A, but the phases of the salient pole teeth of the motor stator magnetic pole 13A and the tooth row of the motor rotor magnetic pole 15A are relatively shifted. Thus, by sequentially energizing the teeth of the motor stator magnetic pole 13A in the circumferential direction while controlling the supply of the current to the rotation drive coil 12A, the teeth of the motor rotor magnetic pole 15A are sequentially attracted, and the first motor rotor 16A as the motor rotor 16A is sequentially attracted. Output shaft A
Is rotated outside the motor stator 14A.

In the second embodiment, the first output shaft A
There is an advantage that machining is easier than in the first embodiment in which the drive motor of the first embodiment has an inner rotor type structure. Other configurations, operations and effects are almost the same as those of the first embodiment.

In each of the above embodiments, the case where the closed type actuator of the present invention is used by being attached to a vacuum chamber is described. However, the present invention is not limited to this. It is also possible to use.

Also, the actuator of the unit to be combined is 2
Although the case where the axes are arranged coaxially at different positions in the radial direction is shown, the actuators of two or more axes may be coaxially arranged at different positions in the radial direction.

[0044]

As described above, according to the first aspect of the present invention,
According to the composite type sealed actuator according to the above, a plurality of units of the closed type actuator are concentrically arranged in parallel at different positions in the radial direction from each other, so that the composite type having the same torque connected in series in the axial direction is used. The overall length of the actuator can be reduced to approximately half of that of the closed type actuator, and the space of the entire device can be used efficiently.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a first embodiment of the present invention.

FIG. 2 is a schematic sectional view of the variable reluctance resolver shown in FIG.

FIG. 3 is a circuit diagram of the resolver.

FIG. 4 is a cross-sectional view of a second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing an example of a conventional composite-type closed actuator.

FIG. 6 is a cross-sectional view showing another example of the conventional composite type sealed actuator.

[Explanation of symbols]

 Reference Signs List 10 Hermetic actuator 10 Hermetic actuator in units of 10A Hermetic actuator in units of 10B 11 Housing 12A Rotary drive coil 12B Rotary drive coil 13A Motor stator magnetic pole 13B Motor stator magnetic pole 14A Motor stator 14B Motor stator 15A Motor rotor magnetic pole 15B Motor rotor magnetic pole 16A Motor rotor 16B Motor rotor 17A Bearing 17B Bearing 18A Bearing 18B Bearing 21A Displacement measuring means 21B Displacement measuring means 28A Sealing partition 28B Sealing partition

Claims (1)

[Claims] 1. A closed-type actuator having a plurality of output shafts coaxially driven independently of each other in a chamber, the motor rotor having rotor magnetic poles connected to each of the plurality of output shafts, A motor stator having stator magnetic poles which are respectively disposed to face each other at an interval with respect to the magnetic pole surface of the motor rotor and are excited by a rotation drive coil, and the motor stator is mounted in a manner airtightly separated from the chamber. A housing, a bearing that rotatably supports the rotation shaft of the motor rotor on the housing, a sealing partition made of a non-magnetic metal material disposed between the opposed motor rotor and the motor stator, and a displacement of the motor rotor. A sealed actuator composed of a displacement measuring means for measuring and a sealed actuator of a unit, Multiple units of sealed actuator serial units, sealed actuator is characterized in that each configured in parallel concentrically different position in the radial direction.