JP2013230031A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor which inhibits the demagnetization of magnets and reduces the emission of an impurity gas in an environment atmosphere where the motor is used.SOLUTION: A motor 1 includes: a motor stator 30; a motor housing 20 and a flange member 24 that form a housing; a motor rotor 40; a bearing device 14; an airtight sealing member 60; an air intake port 61H; and an exhaust port 68. The airtight sealing member 60 hermetically seals so that a gas in a space where the motor stator 30 is disposed does not circulate into a space where the motor rotor 40 is disposed. The air intake port 61H draws a gas a1 ventilated on at least parts of surfaces of the magnets 42.

Description

  The present invention relates to a motor used in a special environment such as, for example, a vacuum environment, an environment decompressed in a sealed space, or an environment containing a process gas.

  Patent Document 1 describes a technology of a sealed actuator (motor) that does not emit impurity gas in an ultra-high vacuum atmosphere, can be positioned with high accuracy, and can maintain sufficient strength. .

JP-A-9-238438

  However, in the motor described in Patent Document 1, no consideration is given to demagnetization of the magnet accompanying the temperature increase of the motor rotor.

  The present invention has been made in view of the above, and an object of the present invention is to provide a motor capable of suppressing demagnetization of a magnet and reducing emission of impurity gas in an environmental atmosphere to be used.

  In order to solve the above-described problems and achieve the object, the motor is provided with a motor stator including an exciting coil and a stator magnetic pole, a housing for fixing the motor stator, and the stator magnetic pole through a predetermined magnetic gap. And a motor rotor having a plurality of magnets arranged in a circumferential direction, a bearing device that rotatably supports the motor rotor on the housing, and a space in which the motor stator is disposed in a space in which the motor rotor is disposed. It includes a hermetic sealing member that is hermetically sealed so that gas does not flow and is disposed in the magnetic gap, and an intake port that sucks in gas that flows through at least part of the surface of the magnet.

  With the above configuration, the motor can release the heat transmitted to the motor rotor by using gas as a medium. For this reason, the motor can reduce the possibility that heat is accumulated in the motor rotor, and can suppress demagnetization of the magnet arranged in the motor rotor. The motor is hermetically sealed so that the gas in the space in which the motor stator is disposed does not flow in the space in which the motor rotor is disposed, so that the impurity gas derived from the motor stator is released into the environmental atmosphere used. The possibility of being reduced can be reduced.

  With the above configuration, even when the motor is used in an environment filled with process gas that may cause corrosion of the magnet, the surface of the magnet is protected by the purge gas flowing in from the intake port. The possibility that the surface of the magnet is exposed to the process gas can be reduced.

  As a desirable mode of the present invention, it is preferable that the intake port is provided on an extension line of the rotation center of the motor rotor.

  With the above configuration, the gas can be uniformly ventilated through the magnet arranged in the circumferential direction of the motor rotor. As a result, the motor can cause the gas cooling effect to act on the magnets arranged in the circumferential direction, reduce the influence of the gas flow on the rotation of the motor rotor, and keep the motor rotation smooth.

  As a desirable aspect of the present invention, it is preferable that the housing further includes a forced exhaust port through which the gas is forcibly exhausted.

  With the above configuration, it is possible to increase the flow rate of the gas that can be sucked at the intake port and to improve the cooling efficiency. Moreover, even if outgas is contained in the space where the motor rotor is arranged, outgas can be discharged from the forced exhaust port. For this reason, the range of selection of the material etc. which can be arrange | positioned in the space where the motor rotor is arrange | positioned can be expanded, and the cost of a motor can be reduced.

  As a preferred aspect of the present invention, the bearing device includes a first bearing device and a second bearing device that are separated from each other in a direction parallel to the rotation center of the motor rotor, and the forced exhaust port is formed with the first bearing device. It is preferable to open between the second bearing device.

  The heat transferred to the bearing device promotes evaporation of the lubricant in the bearing device. With the above configuration, heat from the first bearing device and the second bearing device is discharged to the outside using gas as a medium. For this reason, the rise in the temperature of the bearing device can be suppressed by transferring the heat in the space where the motor rotor is arranged to the gas and taking it away. Thereby, evaporation of the lubricant in the bearing device is suppressed, and the motor can extend the life of the bearing device.

  As a desirable mode of the present invention, a differential pressure is generated between the space and the space in the housing through which the forced exhaust port communicates, including a plurality of throttle channels that divide the space inside the housing. preferable.

  With the above configuration, it is possible to reduce the possibility that a differential pressure is generated and the gas flowing in from the intake port leaks to other than the forced exhaust port.

  As a desirable aspect of the present invention, the housing further includes a first forced exhaust port and a second forced exhaust port from which the gas is forcibly exhausted, and the first forced exhaust port and the second forced exhaust port It is preferable to provide a throttle channel for narrowing the channel between them.

  With the above configuration, a space provided with the second forced exhaust port is created between spaces having different pressure differences, and the gas flowing into the space provided with the second forced exhaust port is exhausted. For this reason, even if the motor is used in a special environment, such as a vacuum environment, an environment where the pressure is reduced in a sealed space, or an atmosphere containing a process gas, it discharges the gas flowing into the special environment from the intake port. It is possible to reduce the possibility of the occurrence.

  As a desirable aspect of the present invention, the housing further includes a first forced exhaust port and a second forced exhaust port from which the gas is forcibly exhausted, and the first forced exhaust port and the second forced exhaust port It is preferable to provide a seal member that seals the flow path therebetween.

  With the above configuration, a space provided with the second forced exhaust port is formed between the spaces having different pressure differences, the space provided with the second forced exhaust port is sealed by the seal member, and the space provided with the second forced exhaust port. Exhaust the gas flowing in. For this reason, even if the motor is used in a special environment, such as a vacuum environment, an environment where the pressure is reduced in a sealed space, or an atmosphere containing a process gas, it discharges the gas flowing into the special environment from the intake port. It is possible to reduce the possibility of the occurrence.

  As a desirable aspect of the present invention, it is preferable that the motor rotor and a load body rotated by the motor rotor are directly connected.

  With this configuration, the motor becomes a so-called direct drive motor and can directly rotate the load body. Further, the motor can be positioned with high accuracy.

  ADVANTAGE OF THE INVENTION According to this invention, the motor which can suppress demagnetization of a magnet and can reduce discharge | release of impurity gas in the environmental atmosphere to be used can be provided.

FIG. 1 is an explanatory diagram illustrating a usage state of the motor according to the first embodiment. FIG. 2 is a schematic diagram illustrating an example of a loading table and a workpiece. FIG. 3 is a partial cross-sectional view schematically showing the configuration of the motor of Embodiment 1 on a virtual plane including the rotation center. FIG. 4 is a partial cross-sectional view schematically showing the motor rotor by cutting the configuration of the motor according to the first embodiment along a virtual plane orthogonal to the rotation center. FIG. 5 is an exploded perspective view showing a magnet attached state. FIG. 6 is a partial cross-sectional view schematically showing a magnet attachment state by cutting along a virtual plane orthogonal to the rotation center. FIG. 7 is a partial cross-sectional view schematically showing the shaft portion gas introduction hole of the shaft portion by cutting the configuration of the motor of Embodiment 1 along a virtual plane orthogonal to the rotation center. FIG. 8 is a partial cross-sectional view schematically showing the discharge hole by cutting the configuration of the motor of Embodiment 1 along a virtual plane orthogonal to the rotation center. FIG. 9 is a partial cross-sectional view schematically showing the configuration of the motor of the second embodiment on a virtual plane including the rotation center. FIG. 10 is a partial cross-sectional view schematically illustrating the configuration of the motor according to the third embodiment on a virtual plane including the rotation center.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present invention is not limited by the contents described in the following embodiments. The constituent elements described below include those that can be easily assumed by those skilled in the art and those that are substantially the same. Furthermore, the constituent elements described below can be appropriately combined.

(Embodiment 1)
FIG. 1 is an explanatory diagram illustrating a usage state of the motor according to the first embodiment. FIG. 2 is a schematic diagram illustrating an example of a loading table and a workpiece. The motor 1 rotates the loading table 52 around the rotation center Zr. For example, as shown in FIG. 2, the loading table 52 includes a disk-shaped plate portion 52 a and an arm portion 52 b for wafer transfer or the like. And the arm part 52b carries the workpiece | work 53. FIG. By rotation of the plate portion 52a of the mounting table 52, the arm portion 52b disposed in the chamber 51 of the vacuum atmosphere Va in the semiconductor manufacturing apparatus is positioned in a state where the workpiece 53a is mounted.

  The motor 1 can directly transmit a rotational force to the work 53 and the loading platform 52 as the load body 50 without rotating a transmission mechanism such as a gear, a belt, or a roller, and can rotate the work 53. The motor 1 is a direct drive motor in which a so-called motor rotation shaft and a load body 50 are directly connected. The motor 1 may be a direct drive motor in which a so-called motor rotation shaft and a work 53 as a load body 50 are directly connected. Moreover, the motor 1 according to the first embodiment is called an outer rotor type as described later, and the motor stator is arranged closer to the rotation center Zr than the motor rotor.

  In general, the degree of integration of a semiconductor manufacturing apparatus is increasing, and at the same time, the density of the IC is being increased by miniaturizing the pattern width of the IC. 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 the demand, it is important to further reduce the impurity gas concentration in the vacuum atmosphere Va. For this reason, in the motor 1 arranged in the mounting hole of the chamber 51, it is necessary to separate the space of the vacuum atmosphere Va from the atmospheric atmosphere At outside the housing. In the present embodiment, the inside of the chamber 51 is set to the vacuum atmosphere Va. However, the vacuum atmosphere Va may be different from the atmospheric atmosphere At such as nitrogen gas or rare gas instead of the vacuum.

  As shown in FIG. 1, when a motor rotation command i is input from an external computer, the motor control circuit 90 outputs a drive signal from a CPU (Central Processing Unit) 91 to a three-phase amplifier (AMP) 92. The drive current Mi is supplied from the AMP 92 to the motor 1. The motor 1 is configured to move the work 53 by rotating the loading platform 52 by the drive current Mi. When the loading table 52 rotates, a detection signal (resolver signal) Sr is output from an angle detector such as a resolver that detects a rotation angle described later. The motor control circuit 90 digitally converts the detection signal Sr with a resolver digital converter (RDC: Resolver to Digital Converter) 93. Based on the digital information of the detection signal Sr from the RDC 93, the CPU 91 determines whether or not the work 53 has reached the command position, and when it reaches the command position, stops the drive signal to the AMP 92.

  As shown in FIG. 1, the motor 1 is connected to a pump P1, which is a gas delivery means, via a suction channel A1, as will be described later. As shown in FIG. 1, the motor 1 may be connected to a pump P2, which is a gas delivery unit, via a discharge channel A2, as will be described later. The pump P1 is driven based on the pump control signal pi1 of the CPU 91, and sends gas to the motor 1 via the suction flow path A1. The pump P2 is driven based on the pump control signal pi2 of the CPU 91, and sends the gas to the motor 1 via the discharge flow path A2. The pumps P1 and P2 may be controlled by a controller (not shown) different from the CPU 91.

  FIG. 3 is a partial cross-sectional view schematically showing the configuration of the motor of Embodiment 1 on a virtual plane including the rotation center. The motor 1 fixes a stator (hereinafter referred to as “motor stator”) 30 that is maintained in a stationary state, a rotor (hereinafter referred to as “motor rotor”) 40 that is rotatably arranged with respect to the motor stator 30, and a motor stator 30. The motor housing 20 attached to the support member of the chamber 51 via the cylindrical flange member 24, the motor rotating body 10 fixed to the motor rotor 40 and rotatable together with the motor rotor 40, the motor housing 20 and the motor rotating body 10 And a vacuum side bearing device 14 that supports the motor rotating body 10 relative to the motor housing 20.

  The motor rotating body 10 includes a rotating plate 10A, and a shaft portion 10S and a shaft portion 10M that are coaxial with the rotation center Zr of the rotating plate 10A. The shaft portion 10S and the shaft portion 10M are connected to form an output shaft by a fixing member 10b such as a bolt so as to extend in the extending direction of the rotation center Zr. In the motor rotating body 10 according to the first embodiment, the rotating plate 10A and the shaft portion 10S are fixed by a fixing member 19 such as a bolt. The output shaft is divided and configured like the shaft portion 10S and the shaft portion 10M, but may be configured as a single unit. At the end of the shaft portion 10M, a loading table 52 is fixed to the vacuum side inner surface 51a side of the chamber 51 by a fixing member 50b such as a bolt.

  The motor housing 20, the motor rotor 40, and the motor stator 30 are all annular structures. The motor rotor 40 and the motor stator 30 are arranged concentrically around the rotation center Zr. Further, the motor 1 is arranged in order of the motor stator 30 and the motor rotor 40 from the rotation center Zr to the outside. Such a motor 1 is called an outer rotor type, and the motor stator 30 is closer to the rotation center Zr than the motor rotor 40.

  The motor housing 20 includes a substantially disk-shaped housing base 21, a housing outer 22, and a housing inner 23. The motor housing 20 of the first embodiment is on the atmosphere side of the chamber 51 and is disposed on the outer surface 51 b side outside the chamber 51. For this reason, the motor housing 20 is fixed to the chamber 51 via the cylindrical flange member 24. The flange member 24 is a hollow structure and includes a flange portion 27, a cylindrical portion 26, a protruding portion 28, and a motor housing fixing portion 29.

  The flange portion 27 of the flange member 24 is disposed on the outer side surface 51b outside the chamber 51, and is fixed via a fixing member 20c such as a bolt. The fixing surface 24a of the housing base 21 of the flange member 24 is on the atmosphere side of the chamber 51, and is fixed to the outer surface 51b of the chamber 51 through a sealing member 20p such as an O-ring. With this structure, the motor 1 according to the first embodiment is disposed so as to be suspended from the mounting hole of the chamber 51 in the atmospheric atmosphere At that is the atmospheric side, and the flange member 24 and the outer side surface 51b outside the chamber 51 are sealed. It has been stopped.

  The flange member 24 preferably has a projecting portion 28 projecting toward the shaft outer peripheral surface 10a side of the shaft portion 10M and the shaft portion 10S on the rotation center Zr side. The protruding portion 28 narrows the gap 12 between the inner peripheral surface 28b of the protruding portion 28 and the shaft outer peripheral surface 10a more than the distance between the inner peripheral surface 26b of the cylindrical portion 26 and the shaft outer peripheral surface 10a. It becomes a labyrinth seal capable of preventing leakage of purge gas (gas).

  The motor housing fixing portion 29 of the flange member 24 is hermetically connected to the motor housing 20 by a fixing member 20b such as a bolt via a sealing member 20a such as an O-ring at the end of the housing outer 22, for example.

  The cylindrical portion 26 of the flange member 24 has a hollow structure, and the shaft portion 10S and the shaft portion 10M which are output shafts connected to the motor rotor 40 and the rotating plate 10A pass through the rotation center Zr.

  The bearing device 14 on the vacuum side is disposed between the inner diameter of the flange member 24 and the shaft portion 10S. The bearing device 14 has an outer ring fixed to the flange member 24 side and an inner ring fixed to the shaft portion 10S side. For example, a bearing restraining member 25 that is fixed to the end of the cylindrical portion 26 with a fixing member 25b such as a bolt and that is annular and fixes the inner ring of the bearing device 14 is disposed inside the flange member 24. . The shaft portion 10M is a bearing restraining member that fixes the outer ring of the bearing device 14.

  In the bearing device 14, the outer ring is fixed to the flange member 24, and the inner ring is fixed to the shaft portion 10S. Thus, the bearing device 14 can rotatably support the motor rotating body 10 and the motor rotor 40 with respect to the housing base 21. For this reason, the motor 1 can rotate the motor rotating body 10 and the motor rotor 40 with respect to the housing base 21 and the motor stator 30.

  The vacuum-side bearing device 14 is preferably a plurality of bearing devices, and the first bearing device 14A and the second bearing device 14B are preferably arranged as a back surface combination. The outer ring of the bearing device 14 is fitted to the flange member 24, and the end face of the outer ring is pressed by the bearing restrainer 25. The first bearing device 14A and the second bearing device 14B are preferably a plurality of angular bearings, but may be other types of bearings such as a deep groove ball bearing.

  Further, the first bearing device 14A and the second bearing device 14B are preferably arranged via the inner spacer 10C and the outer spacer 20C. An annular space cc is formed between the inner spacer 10C and the outer spacer 20C. Further, the inner spacer 10C and the outer spacer 20C can increase the allowable moment load by increasing the distance between the first bearing device 14A and the second bearing device 14B.

  The rotation center Zr side of the bearing restraining member 25 preferably has a protruding portion 23a that protrudes toward the shaft portion 10S. The protrusion 25a serves as a labyrinth seal that narrows the gap l1 between the bearing restraining member 25 and the shaft portion 10S and prevents foreign matter from entering or leakage of a gas a6 described later. Further, the protrusion 25a can reduce the possibility that the lubricant of the second bearing device 14B is pushed out to the outside by a gas a6 to be described later, resulting in poor lubrication.

  The inner ring and the outer ring of the bearing device 14 are made of martensitic stainless steel or the like. With this structure, since the inner ring and the outer ring of the bearing device 14 can be hardened by quenching, rust resistance and durability can be improved. The rolling elements of the bearing device 14 are formed of ceramic balls or the like. Since the rolling element of the bearing device 14 is made of a material different from the material of the inner ring and the outer ring of the bearing device 14, durability can be improved. More preferably, spacer balls such as martensitic stainless steel are disposed between the rolling elements of the bearing device 14. This structure can prevent the rolling elements of ceramic balls from contacting each other.

  Or the inner ring | wheel and the outer ring | wheel of the bearing apparatus 14 can also be formed with austenitic stainless steel, and rust resistance and durability can be improved by performing a surface hardening process. In this case, the rolling elements of the bearing device 14 are made of martensitic stainless steel and can be hardened by quenching, so that rust resistance and durability can be improved. Moreover, since the rolling element of the bearing apparatus 14 is a material different from the material of the inner ring | wheel and outer ring | wheel of the bearing apparatus 14, durability can be improved. A cage (not shown) is made of austenitic stainless steel or the like, and prevents the rolling elements of the first bearing device 14A and the second bearing device 14B from contacting each other.

  The motor housing 20 is disposed on the lower surface of the flange member 24 and is fixed via a fixing member 20b such as a bolt. The bottom surface 21 a of the housing base 21 of the motor housing 20 is exposed to an atmospheric atmosphere At that is the atmospheric side of the chamber 51.

  The housing base 21 includes a center protrusion 21A that protrudes in the vicinity of the rotation center Zr. The center protrusion 21A fixes an airtight sealing member 60 described later.

  The housing inner 23 is a projecting portion that is a concentric circle projecting from the housing base 21 so as to surround the rotation center Zr. The housing outer 22 is a projecting portion that is a concentric circle projecting from the housing base 21 so as to surround the housing inner 23. For this reason, the upper surface 21 b of the housing base 21 includes an annular groove surrounded by the housing inner 23 and the housing outer 22.

  A motor stator 30 is fastened to a side surface of the housing inner 23 opposite to the rotation center Zr side by a fixing member such as a bolt. Thereby, the motor stator 30 is positioned and fixed with respect to the housing base 21. The central axis of the motor stator 30 coincides with the rotation center Zr of the motor rotor 40.

  The motor stator 30 includes a stator core 31 and an excitation coil 32. In the motor stator 30, an exciting coil 32 is wound around a stator core 31. A wiring 32a for supplying power from a power source is connected to the motor stator 30, and power is supplied from the motor control circuit 90 to the excitation coil 32 through this wiring 32a. .

  The motor rotor 40 has a cylindrical shape in which the inner diameter of the motor rotor 40 is larger than the outer diameter dimension of the motor stator 30. The motor rotor 40 includes a rotor yoke 41 and a magnet 42 attached to the inner periphery of the rotor yoke 41. The magnet 42 will be described later.

  The rotating plate 10A has a disk shape, and the rotor yoke 41 is integrated with the outer edge. The motor rotor 40 has a cylindrical shape in which a disk-shaped rotating plate 10A at one end serves as a lid and the other end is open. The motor rotor 40 may be fixed to the cylindrical rotating plate 10A by a fixing member such as a bolt. The rotation plate 10 </ b> A has a central axis that is coaxial with the rotation center Zr of the motor 1.

  The air bearing device 74 supports the inner rotor 82 so as to be rotatable with respect to the central protrusion 21A. Moreover, it is preferable that the bearing device 74 on the atmosphere side fits and fixes the plurality of deep groove ball bearings 74A and 74B to the center protruding portion 21A described above. The deep groove ball bearings 74 </ b> A and 74 </ b> B are subjected to a constant pressure preload by a preload spring 75.

  The preload spring 75 can suppress an excessive change in the preload due to a temperature change in the space where the motor stator 30 is disposed. For this reason, the preload spring 75 increases the lost motion caused by the torsion spring constant of the magnetic coupling effect and the hysteresis of the starting torque of the bearing device 74 on the atmosphere side, or unwanted vibration of the angle detector 70 due to the preload loss. Can be suppressed. The lost motion refers to a difference between both stop positions due to positioning in a positive direction to a certain position and positioning in a negative direction.

  The motor 1 includes a coupling magnet 84 and a coupling yoke 81 that supports the coupling magnet 84. The magnet 42 of the motor rotor 40 is disposed to face the coupling magnet 84 via an airtight sealing member 60 described later, and includes a plurality of coupling magnets 84 and a holder that holds the coupling magnets 84 and the coupling yoke 81. The inner rotor 82. The coupling yoke 81 is fixed to the inner rotor 82 by a fixing member 83 such as a bolt.

  With this configuration, a magnetic force generated between the magnet 42 of the motor rotor 40 and the coupling magnet 84 acts, and the inner rotor 82 rotates in conjunction with the rotation of the motor rotor 40. For example, magnetic attraction or magnetic repulsion is generated between the magnet 42 of the motor rotor 40 and the coupling magnet 84, so that a so-called magnetic coupling effect is generated, and the motor rotor 40 follows the inner rotor 82.

  The torsion spring constant of the magnetic coupling effect is substantially constant, although the residual magnetic flux density of the magnet is affected by temperature and the torsion spring constant slightly changes, and the rotational moment of the inner rotor 82 is also constant. Therefore, the resonance frequency determined from the torsion spring constant of the magnetic coupling effect and the rotation moment of the inner rotor 82 is also constant, and this resonance frequency is independent of the rotation moment of the load body 50 loaded on the motor rotor 40. In the motor 1 of the present embodiment, the vibration of the inner rotor 82 is suppressed by attenuating the vicinity of the resonance frequency with the notch filter or the low-pass filter from the control band of the motor control circuit 90 described above.

  Coupling magnet 84 is preferably multipolarly magnetized on the surface of a single magnet, and preferably has opposite polarities facing each other at a position facing motor rotor 40.

  The motor 1 preferably includes an angle detector 70. The angle detector 70 is, for example, a resolver, and can detect the rotational positions of the motor rotor 40 and the motor rotor 10 with high accuracy.

  The angle detector 70 is a resolver stator 71A, 71B that is maintained in a stationary state, and a resolver rotor 72A that is disposed to face the resolver stator 71A, 71B with a predetermined gap therebetween and is rotatable with respect to the resolver stator 71A, 71B. 72B. The resolver stators 71 </ b> A and 71 </ b> B are disposed in the housing inner 23. The resolver rotors 72 </ b> A and 72 </ b> B are disposed on the inner rotor 82.

  When the exciting coil 32 of the motor stator 30 is excited and the motor rotor 40 is rotationally driven, the inner rotor 82 is rotationally driven simultaneously. With this configuration, the rotation angle of the motor rotor 40 can be detected by the angle detector 70 through the hermetic sealing member 60.

  The resolver stators 71A and 71B have an annular laminated core in which a plurality of stator magnetic poles are formed at equal intervals in the circumferential direction, and a resolver coil is wound around each stator magnetic pole. Each resolver coil is connected to a wiring 73 for outputting a detection signal (resolver signal) Sr.

  The resolver rotors 72 </ b> A and 72 </ b> B are constituted by hollow annular laminated iron cores and are fixed to the outside of the inner rotor 82. The arrangement position of the angle detector 70 is not particularly limited as long as the rotation of the motor rotor 40 (the motor rotating body 10) can be detected, and any position depending on the shape of the motor rotating body 10 and the motor housing 20 is possible. Can be arranged.

  When the motor rotor 40 rotates, the motor rotor 10 rotates together with the motor rotor 40, and the resolver rotors 72A and 72B also rotate in conjunction with the motor rotor 40. Thereby, the reluctance between resolver rotor 72A, 72B and resolver stator 71A, 71B changes continuously. Resolver stators 71A and 71B detect a change in reluctance, and RDC 93 converts detection signal Sr described above into a digital signal. The CPU 91 of the motor control circuit 90 that controls the motor 1 calculates the position and rotation angle of the motor rotor 10 and the motor rotor 40 that are linked to the resolver rotors 72A and 72B per unit time based on the electrical signal of the RDC 93. Can do. As a result, the motor control circuit 90 that controls the motor 1 can measure the rotation state (for example, the rotation speed, the rotation direction, or the rotation angle) of the motor rotating body 10.

  The resolver rotor 72A described above has an annular shape having an eccentric outer periphery. Therefore, when the resolver rotor 72A rotates along with the rotation of the motor rotor 40, the distance between the resolver stator 71A and the resolver stator 71A is continuously changed in the circumferential direction, and the reluctance between the two is continuously changed depending on the position of the resolver rotor 72A. To change. For each rotation of the resolver rotor 72A, a single pole resolver signal is output in which the fundamental wave component of the reluctance change is one cycle, and the resolver rotor 72A and the resolver stator 71A become a so-called single pole resolver.

  The resolver rotor 72B has a plurality of salient pole-like teeth formed at equal intervals in the circumferential direction. Therefore, when the resolver rotor 72B rotates with the rotation of the motor rotor 40, the distance between the resolver stator 71B is periodically changed in the circumferential direction, and the reluctance between the two depends on the position of the teeth of the resolver rotor 72B. It changes continuously. For each rotation of the resolver rotor 72B, a multipolar resolver signal is output in which the fundamental wave component of the reluctance change has a multi-cycle, and the resolver rotor 72B and the resolver stator 71B become a so-called multipolar resolver.

  Thus, the motor 1 can grasp the absolute position of the motor rotating body 10 by including the angle detector 70 having different periods of the fundamental wave component of the reluctance change for one rotation of the motor rotor 40, The accuracy of measuring the rotation state (for example, rotation speed, rotation direction, or rotation angle) of the motor rotating body 10 can be increased. Further, the motor 1 can perform positioning without having to perform a pole detection operation by one-phase energization or an origin return operation.

  In the motor 1, the load body 50 is directly fixed to the motor rotating body 10 by a fixing member such as a bolt. In the motor described in Patent Document 1 described above, when the temperature of the work 53 that is the load body 50 is high, the heat of the work 53 may be transmitted to the motor rotor 40 via the loading table 52 and the motor rotating body 10. . In the motor described in Patent Document 1 described above, when the transmitted heat is accumulated in the motor rotor 40, the magnet 42, which is a permanent magnet disposed in the motor rotor 40, may be demagnetized. When the magnet 42 is demagnetized, the motor 1 may not be able to fully exhibit the motor torque.

  Further, in the motor described in Patent Document 1 described above, the lubricant in the bearing device 14 may be deteriorated or evaporated by the heat transmitted to the motor rotor 40. When the lubricant deteriorates or evaporates, the friction of the bearing device 14 becomes excessive, and the output torque may be reduced. In addition, spike-like torque fluctuations may occur, and the workpiece 53 mounted on the load body 50 may be damaged. As described above, the motor described in Patent Document 1 described above may cause vibration of the motor rotating body 10, and the vibration of the motor rotating body 10 is transmitted to the load body 50.

  In the motor described in Patent Document 1 described above, the motor rotor 40 is disposed in a space communicating with the vacuum atmosphere Va on the vacuum side, and the cooling effect due to heat transfer tends to be small. For example, the cooling effect by gas convection cannot be obtained in a vacuum as compared with the atmosphere. As a result, the motor rotor 40 tends to accumulate heat. In addition, components placed in a vacuum are often polished with a clean metallic color on the component surface in order to reduce the outgassing of deposits, and the cooling effect of heat radiation due to radiation tends to be small.

  However, compared with the motor described in Patent Document 1 described above, the motor 1 according to the first embodiment can suppress the demagnetization of the magnet 42 and reduce the emission of impurity gas in the environmental atmosphere to be used. . The motor 1 according to the first embodiment includes a motor stator 30, a motor housing 20 and a flange member 24, a motor rotor 40, a bearing device 14, an airtight sealing member 60, an intake port 61H, and a forced exhaust port 68. Including. The motor 1 according to the first embodiment can release the heat transmitted to the motor rotor 40 from the forced exhaust port 68 via a purge gas that is a gas sucked into the space where the motor rotor 40 is disposed from the intake port 61H. For this reason, the motor 1 can obtain the cooling effect by the convection of gas, can reduce the possibility that heat is accumulated in the motor rotor 40, and can suppress the demagnetization of the magnet 42 arranged in the motor rotor 40. it can.

  FIG. 4 is a partial cross-sectional view schematically showing the motor rotor by cutting the configuration of the motor according to the first embodiment along a virtual plane orthogonal to the rotation center. As shown in FIG. 4, the motor rotor 40 includes a rotor yoke 41 and a magnet 42. The rotor yoke 41 is formed in a cylindrical shape. The rotor yoke 41 is preferably made of a ferromagnetic low carbon steel, and the surface thereof is preferably plated with nickel. By applying nickel plating, the rotor yoke 41 can prevent rust and reduce outgas.

  A plurality of magnets 42 are attached along the inner peripheral surface of the rotor yoke 41, and a plurality of magnets 42 are provided. The magnet 42 is a permanent magnet, and S poles and N poles are alternately arranged at equal intervals in the circumferential direction of the rotor yoke 41. Accordingly, the number of poles of the motor rotor 40 shown in FIG. 4 is 20 poles in which the N pole and the S pole are alternately arranged in the circumferential direction of the rotor yoke 41 on the outer peripheral side of the rotor yoke 41.

  As shown in FIG. 4, the motor 1 of this embodiment has a slot combination configuration of 20 poles and 18 slots. For example, it is generally known that a slot combination configuration of 10 poles and 9 slots is a fractional slot and has a small cogging force but easily generates a magnetic attractive force in the radial direction. On the other hand, the motor 1 of the present embodiment has a configuration twice as large as a slot combination configuration of 10 poles and 9 slots, and cancels the radial magnetic attraction force, so that the roundness of the stator and the rotor is reduced. Alternatively, vibration during rotation can be reduced without increasing the coaxiality, cogging can be suppressed, and very smooth rotation can be obtained. Note that the number of poles of the motor rotor 40 and the number of slots of the motor stator 30 are not limited to the configuration of 20 poles and 18 slots, and can be appropriately changed as necessary.

  Further, as the permanent magnet of the magnet 42, for example, an Nd—Fe—B magnet (neodymium magnet) can be used. The magnet 42 is preferably plated with nickel. By applying nickel plating, the magnet 42 can prevent rust and reduce outgas even if it is disposed in the vacuum atmosphere Va.

  The motor 1 can reduce the possibility of heat being accumulated in the motor rotor 40, and can suppress demagnetization of the magnet 42 disposed in the motor rotor 40. For this reason, the motor 1 can use a neodymium magnet that has a high energy product but easily demagnetizes at a high temperature as the magnet 42 as compared with other rare earth magnets, and the motor rotor 40 can be downsized. As a result, the motor 1 becomes compact, and for example, a mounting hole opened in the support member of the chamber 51 can be made small.

  FIG. 5 is an exploded perspective view showing a magnet attached state. FIG. 6 is a partial cross-sectional view schematically showing a magnet attachment state by cutting along a virtual plane orthogonal to the rotation center. A pair of magnet pressing members 43 for positioning the magnet 42 shown in FIG. 5 are provided on the inner periphery of the rotor yoke 41 shown in FIG. The pair of magnet pressing members 43 is a non-magnetic material, and is formed of, for example, austenitic stainless steel or the like, and can reduce the rate at which the interference changes due to the temperature change of the motor rotor 40. The pair of magnet pressing members 43 are fixed to the inner periphery of the rotor yoke 41 by press fitting or shrink fitting.

  In general, an adhesive is often used to fix a segmented magnet in a motor. However, since the motor 1 of Embodiment 1 is disposed in the vacuum atmosphere Va, it is necessary to reduce the outgas emitted from the adhesive. Further, the adhesive exposed to the vacuum atmosphere Va is deteriorated, and there is a possibility that the adhesive strength is deteriorated. The motor 1 of the first embodiment can fix the magnet 42 by using the magnet pressing member 43 without using an adhesive. As a result, the motor 1 according to the first embodiment can ensure the positioning of the magnet 42 and reduce the emission of impurity gas in the environmental atmosphere to be used.

  As shown in FIG. 5, the magnet pressing member 43 includes an annular portion 44A along the inner peripheral diameter of the rotor yoke 41 and positioning portions 44B that are a plurality of convex portions provided on the annular portion 44A. As for the positioning part 44B, when the number of poles of the magnet is n, a plurality of n-1 pieces are provided in the circumferential direction. A space between the adjacent positioning portions 44 </ b> B serves as a recess for accommodating the magnet 42. The magnet 42 is sandwiched between recesses that accommodate the magnet 42. The magnet 42 is accommodated between the pair of magnet pressing members 43 and attached to the inner periphery of the rotor yoke 41. In the first embodiment, the magnet 42 is a segmented magnet (segment structure) that is affixed along the contact surface of the inner peripheral surface of the rotor yoke 41 and is provided in plural.

  As shown in FIG. 6, the circumferential end surface of the magnet 42 is such that the intersection Mr of the tangent to the positioning portion 44B is closer to the magnet 42 than the rotation center Zr. For this reason, the magnet pressing member 43 reduces the possibility that the magnet 42 protrudes to the rotation center Zr side from the positioning portion 44B. By making the radius of curvature of the circular arc in the rotational direction at the outer peripheral portion (outer peripheral surface) in the radial direction of the magnet 42 slightly smaller than the radius of curvature of the inner peripheral diameter of the rotor yoke 41, the outer peripheral portion in the radial direction of the magnet 42 is changed. It is more preferable to make line contact with the inner peripheral diameter of the rotor yoke 41 at two points. As a result, the motor 1 can reduce the possibility that the magnet 42 rattles against the rotor yoke 41.

  The motor stator 30 is provided in a cylindrical shape so as to surround the housing inner 23 on the rotation center Zr side. As shown in FIG. 4, the motor stator 30 has a stator core (stator magnetic pole) 31 in which teeth 31a are arranged at equal intervals in the circumferential direction centering on the rotation center Zr described above, and a back yoke 31b is integrally disposed. . The motor stator 30 is not limited to such an integral core, and may be a divided core in which a plurality of divided stator cores 31 are arranged at equal intervals in the circumferential direction around the rotation center Zr described above. . The stator core 31 is fixed to the housing base 21 through the housing inner 23.

  The stator core 31 is formed by laminating and bundling a plurality of teeth 31a formed in substantially the same shape in the direction of the rotation center Zr. The stator core 31 is made of a magnetic material such as an electromagnetic steel plate. The motor stator 30 forms an annular shape when a plurality of stator cores 31 are combined.

  The exciting coil 32 shown in FIG. 4 is a linear electric wire. The exciting coil 32 is concentratedly wound around the teeth 31a of the stator core 31 via an insulator. The exciting coil 32 has a U-phase forward winding, U-phase reverse winding, U-phase forward winding, V-phase forward winding, V-phase reverse winding, V-phase forward winding, W-phase forward winding, W-phase reverse winding, and W-phase forward winding Wired by repeating the sequence. With this configuration, the number of magnetic poles can be reduced, and the coil amount can be reduced because the coil ends are shortened compared to distributed winding. As a result, the cost can be reduced and the motor 1 can be made compact. The insulator is a member for insulating the exciting coil 32 and the stator core 31 and is formed of a heat resistant member.

  The exciting coil 32 may be distributedly wound around a plurality of teeth 31 a of the stator core 31. With this configuration, the number of magnetic poles is increased and the distribution of magnetic flux is stabilized, so that torque ripple can be suppressed. The exciting coil 32 may be toroidally wound around the outer periphery of the back yoke 31b. With this configuration, a magnetic flux distribution equivalent to distributed winding can be generated. As a result, torque ripple can be suppressed.

  By combining a plurality of stator cores 31 thus configured as shown in FIG. 3, the motor stator 30 has a shape that can surround the housing inner 23. That is, the stator core 31 is annularly arranged with a gap serving as the magnetic gap G inside the rotor yoke 41 (on the side far from the rotation center Zr).

  As shown in FIG. 3, the hermetic sealing member 60 includes a top plate portion 61, a body portion 62, and a mouth flange portion 63. As shown in FIG. 4, the hermetic sealing member 60 has a body portion 62 disposed in a magnetic gap G between the stator core 31 and the rotor yoke 41, and a space in which the motor stator 30 is disposed in a space in which the motor rotor 40 is disposed. The partition wall is sealed so that no gas flows.

  The hermetic sealing member 60 is an integrally molded product obtained by cutting the top plate portion 61, the body portion 62, and the mouth flange portion 63 from austenitic stainless steel or the like. The trunk | drum 62 is formed in the thin tubular shape (thin cylinder shape with a thin thickness) by the thickness of 0.5 mm or more and 0.6 mm or less, for example. With this structure, the body portion 62 can suppress eddy current loss due to a magnetic field change.

  The top plate portion 61 is fitted and connected to the center protruding portion 21 </ b> A of the housing base 21 in the vicinity of the rotation center Zr of the housing base 21. The top plate portion 61 may be fixed to the housing base 21 with a fixing member such as a bolt (not shown). The top plate portion 61 can be connected to the housing base 21 to suppress deformation due to a pressure difference between the vacuum atmosphere Va and the atmospheric atmosphere At.

  The mouth flange portion 63 is fixed to the upper surface 21b of the housing base 21 with a fixing member 64 such as a bolt via a sealing member 65 such as an O-ring. With this structure, the annular groove surrounded by the housing inner 23 and the housing outer 22 is partitioned by the hermetic sealing member 60 into a space where the motor rotor 40 is arranged and a space where the motor stator 30 is arranged. Gas can be prevented from flowing to the vacuum side.

  As shown in FIG. 3, the hermetic sealing member 60 is provided with an intake port 61H for sucking purge gas. Further, the cylindrical portion 26 described above is provided with a forced exhaust port 68 for forcibly exhausting the purge gas.

  For example, the pump P1 supplies the clean gas a1 to the intake connector 66 to which the pump P1 is connected via the intake flow path A1. The gas a1 serving as the purge gas is preferably an inert gas such as nitrogen.

  The gas a1 reaches the intake port 61H via the communication hole 67 of the central protrusion 21A. That is, the intake port 61H communicates with the communication hole 67 and the intake connector 66. The communication hole 67 and the intake port 61H are provided on an extension line of the rotation center Zr of the motor rotor 40. The gas a1 is sent to the intake port 61H, and is discharged from the intake port 61H as the gas a2 into the space where the motor rotor 40 is arranged, separated from the atmospheric atmosphere At by the hermetic sealing member 60. Since the intake port 61H is provided on an extension line of the rotation center Zr of the motor rotor 40, the gas a2 can be evenly sent toward the outside in the radial direction of the motor rotor 10. The gas a2 passes through at least a part of the surface of the magnet 42 as the gas a3. For this reason, the inlet 61H is an inlet for sucking in the gas a3 that ventilates at least a part of the surface of the magnet 42.

  For example, the gas a <b> 3 can pass between the body 62 and the surface of the magnet 42 to cool the magnet 42. The gas a3 is reversed as the gas a4 at the mouth flange portion 63 and passes between the outer side in the radial direction of the rotor yoke 41 and the housing outer 22 while cooling the rotor yoke 41 as the gas a5. The gas a5 reaches the position of the gas a6. The gas a6 flows between the flange member 24 and the motor rotating body 10 in a direction approaching the rotation center Zr, and is guided to the shaft portion gas introduction hole 10G opened in the shaft portion 10S. The diameter d1 of the shaft portion gas introduction hole 10G is preferably larger than the gap 11 described above. Thereby, the protrusion part 25a can suppress that the gas a6 flows into the 2nd bearing apparatus 14B.

  FIG. 7 is a partial cross-sectional view schematically showing the shaft portion gas introduction hole of the shaft portion by cutting the configuration of the motor of Embodiment 1 along a virtual plane orthogonal to the rotation center. As shown in FIG. 7, a plurality of shaft portion gas introduction holes 10G are provided radially outward with the rotation center Zr as a center. The number of shaft portion gas introduction holes 10G may be one, but when a plurality of shaft portion gas introduction holes 10G are equally disposed in the circumferential direction, the gas a6 can be collected more evenly from the periphery of the shaft portion 10S. The shaft portion 10S includes a gas introduction path 10H including the rotation center Zr. The gas introduction path 10H is connected to the shaft portion gas introduction hole 10G. As shown in FIG. 3 and FIG. 7, the gas a <b> 6 guided to the shaft part gas introduction hole 10 </ b> G opened in the shaft part 10 </ b> S joins in the gas introduction path 10 </ b> H and flows as the gas a <b> 7.

  FIG. 8 is a partial cross-sectional view schematically showing the discharge hole by cutting the configuration of the motor of Embodiment 1 along a virtual plane orthogonal to the rotation center. As shown in FIG. 8, a plurality of shaft portion gas discharge holes 10J are provided radially outward from the rotation center Zr. The number of the shaft portion gas discharge holes 10J may be one, but when a plurality of the shaft portion gas discharge holes 10J are equally arranged in the circumferential direction, the gas a8 can be discharged more uniformly from the periphery of the shaft portion 10S. The gas introduction path 10H described above is connected to one end of the shaft part gas discharge hole 10J. The other end of the shaft portion gas discharge hole 10J is connected to a hole communicating with the space cc formed in the inner spacer 10C.

  As shown in FIG. 8, the forced exhaust port 68 is connected to a hole communicating with the space cc opened in the outer spacer 20 </ b> C. The forced exhaust port 68 is opened between the first bearing device 14A and the second bearing device 14B. For this reason, the shaft portion gas discharge hole 10J and the forced exhaust port 68 communicate with each other. The gas a7 passes through the shaft portion gas discharge hole 10J as the gas a8. The gas a9 that has passed through the shaft portion gas discharge hole 10J enters the space cc and is guided to the forced exhaust port 68. The diameter d2 of the hole leading to the space cc opened in the outer spacer 20C is preferably larger than the gap 11 or the gap 12 described above.

  The forced exhaust port 68 is connected to an exhaust connector 69 attached to the outer peripheral surface 26 a of the cylindrical portion 26. The number of exhaust connectors 69 may be one, but when a plurality of exhaust connectors 69 are equally disposed in the circumferential direction, the gas a9 can be discharged more uniformly from the cylindrical portion 26. The gas a9 that has passed through the forced exhaust port 68 passes through the exhaust passage A2 via the exhaust connector 69 and returns to the pump P2. Thus, the pump P2 forcibly exhausts the gas a9 through the forced exhaust port 68. For this reason, it is possible to increase the flow rate of the purge gas (gas a1, gas a2, gas a3, gas a4, gas a5, gas a6, gas a7, gas a8 and gas a9) that can be sucked in from the intake port 61H, thereby improving the cooling efficiency. it can.

  The gas flow of the purge gas such as gas a1, gas a2, gas a3, gas a4, gas a5, gas a6, gas a7, gas a8 and gas a9 takes the heat of the magnet 42 and discharges it out of the motor 1. Can do. The pumps P <b> 1 and P <b> 2 are gas delivery means for forcibly cooling the purge gas by flowing the gas in the space where the motor rotor 40 is disposed. The pumps P1 and P2 can increase the amount of cooling by increasing the volume per time for discharging or sucking gas. Since the motor 1 separates the pump P1 and the pump P2 to form the gas flow of the purge gas, the substance contained in the gas a9 in the discharge passage A2 is not mixed with the gas a1, and the gas a1 is cleaned. State.

  When the workpiece 53 is at a high temperature, the heat transmitted to the motor rotor 40 may heat the magnet 42. With the above configuration, the motor 1 can suppress an increase in the temperature of the magnet 42 by taking the heat of the magnet 42 using gas (purge gas) as a medium. Thereby, the motor 1 can suppress the demagnetization of the magnet 42.

  Generally, the heat transferred to the bearing device 14 promotes evaporation of the lubricant in the bearing device 14. In the motor 1 according to the first embodiment, when the work 53 is at a high temperature, the heat transmitted to the bearing device 14 takes the heat of the bearing device 14 by using a gas (purge gas) as a medium, whereby the lubricant of the bearing device 14 is obtained. Can reduce the possibility of deterioration or evaporation. That is, the motor 1 according to the first embodiment includes the first bearing device 14A and the second bearing device 14B in which the bearing device 14 is separated from each other in a direction parallel to the rotation center Zr of the motor rotor 40, and the first through the flow of the gas a9. Heat from the bearing device 14A and the second bearing device 14B is discharged to the outside using the gas a9 as a medium. For this reason, the motor 1 of Embodiment 1 can suppress the temperature rise of the bearing device 14 by transferring the heat in the space where the motor rotor 40 is arranged, for example, the space cc, to the gas a9 and taking it away. Thereby, deterioration or evaporation of the lubricant is suppressed, so that the possibility that the friction of the bearing device 14 becomes excessive and the output torque decreases is reduced. In the motor 1 according to the first embodiment, spike-like torque fluctuations due to poor lubrication are suppressed, and the possibility of damaging the workpiece 53 mounted on the load body 50 can be reduced. Further, since the purge gas flows between the first bearing device 14A and the second bearing device 14B, the cooling efficiency of the first bearing device 14A and the second bearing device 14B can be increased.

  Note that the lubricant of the first bearing device 14A and the second bearing device 14B is preferably grease based on fluorine-based synthetic oil. The fluorine-based synthetic oil is, for example, perfluoropolyether (PFPE) oil. In general, fluorine-based synthetic oil has a low vapor pressure and can suppress volatilization even in a vacuum.

  As described above, the motor 1 according to the first embodiment includes the motor stator 30, the motor housing 20 and the flange member 24, which are the housing, the motor rotor 40, the bearing device 14, the hermetic sealing member 60, and the air inlet 61H. And a forced exhaust port 68. The motor stator 30 includes an exciting coil 32 and a stator core 31. A housing inner 23 of the motor housing 20 fixes the motor stator 30. The motor rotor 40 includes a plurality of magnets 42 that face the stator core 31 via a predetermined magnetic gap G and are arranged in the circumferential direction. The bearing device 14 supports the motor rotor 40 rotatably on the housing outer 22 of the motor housing 20. The hermetic sealing member 60 is sealed so that the gas in the space in which the motor stator 30 is disposed does not flow in the space in which the motor rotor 40 is disposed. Further, the body portion 62 of the hermetic sealing member 60 is disposed in the magnetic gap G. The intake port 61H sucks in the gas a1 that flows through at least a part of the surface of the magnet 42. The forced exhaust port 68 exhausts the gas sucked from the intake port 61H to the outside of the motor 1.

  The heat transmitted to the motor rotor 40 can escape using the gas a3 flowing through at least a part of the surface of the magnet 42 as a medium. For this reason, the possibility that heat is accumulated in the motor rotor 40 can be reduced, and demagnetization of the magnet 42 disposed in the motor rotor 40 can be suppressed. Further, since the hermetic sealing member 60 is sealed so that the gas in the space in which the motor stator 30 is disposed does not flow in the space in which the motor rotor 40 is disposed, the environmental atmosphere and vacuum used by the impurity gas resulting from the motor stator 30 The possibility of being released into the atmosphere Va can be reduced.

  In the first embodiment, the chamber 51 includes the vacuum atmosphere Va. For example, instead of the vacuum atmosphere Va, the chamber 51 may hold a process gas that may cause corrosion of the magnet 42 or the like. Thus, even in an environment where the chamber 51 is filled with the process gas, the surface of the magnet 42 is protected by the purge gas flowing from the intake port 61H to the magnet 42, so that the surface of the magnet 42 becomes the process gas. The possibility of exposure can be reduced.

  As described above, the first bearing device 14A and the second bearing device 14B are arranged via the inner spacer 10C and the outer spacer 20C. The motor 1 of the first embodiment can increase the volume of the space cc and increase the cooling efficiency by increasing the length of the inner spacer 10C and the outer spacer 20C in the direction parallel to the rotation center Zr. In addition, the hole formed in the inner spacer 10C and the hole formed in the outer spacer 20C are the same as the position in the direction parallel to the rotation center Zr (both are in a plane orthogonal to the rotation center Zr). The positions may be different.

  When the hole drilled in the inner spacer 10C is on a different plane in the plane perpendicular to the rotation center Zr and the hole drilled in the outer spacer 20C, the hole drilled in the inner spacer 10C is close to the first bearing device 14A. The hole opened in the outer spacer 20C is close to the second bearing device 14B. According to this structure, the flow path of the gas a9 from the hole opened in the inner spacer 10C to the hole opened in the outer spacer 20C can be lengthened. As a result, the heat taken away by the gas a9 increases, so that the cooling efficiency can be increased. Further, since the hole opened in the inner spacer 10C and the hole opened in the outer spacer 20C are close to the first bearing device 14A and the second bearing device 14B, the cooling of the first bearing device 14A and the second bearing device 14B is reduced. Promoted.

  As described above, the motor 1 according to the first embodiment uses the pair of magnet pressing members 43 to suppress outgassing in a space where the motor rotor 40 is disposed. The motor 1 of the first embodiment includes a forced exhaust port 68 and forcibly discharges the purge gas. For this reason, even if there is outgas in the space where the motor rotor 40 is disposed, the possibility that the outgas is released into the vacuum atmosphere Va can be reduced by exhausting the outgas from the forced exhaust port 68 together. For this reason, since the motor 1 can use an adhesive agent etc. instead of the pair of magnet pressing members 43 described above, the configuration of the motor 1 is simplified, and the cost of the motor 1 can be suppressed.

(Embodiment 2)
FIG. 9 is a partial cross-sectional view schematically showing the configuration of the motor of the second embodiment on a virtual plane including the rotation center. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in Embodiment 1 mentioned above, and the overlapping description is abbreviate | omitted.

  Similarly to the motor 1 of the first embodiment, the motor 1 of the second embodiment is referred to as an outer rotor type, and the motor stator 30 is disposed closer to the rotation center Zr than the motor rotor 40. The motor 1 of the second embodiment includes a first forced exhaust port 68A and a second forced exhaust port 68B, which are a plurality of exhaust ports, as compared with the motor 1 of the first embodiment.

  The first forced exhaust port 68A has the same structure as the forced exhaust port 68 of the first embodiment described above, and is connected to and communicates with an exhaust connector 69A attached to the cylindrical portion 26A. The gas a9 that has passed through the first forced exhaust port 68A passes through the exhaust passage A2 via the exhaust connector 69A. Thus, the pump P2 sucks the gas a9 through the forced exhaust port 68A and the discharge flow path A2, and forcibly exhausts it. For this reason, the pump P2 increases the flow rate of the purge gas (gas a1, gas a2, gas a3, gas a4, gas a5, gas a6, gas a7, gas a8, and gas a9) that can be sucked in the intake port 61H, and cooling efficiency Can be increased.

  The flange member 24A of the second embodiment is a hollow structure, and includes a flange portion 27, a cylindrical portion 26A, a protruding portion 28A, a protruding portion 28B, and a motor housing fixing portion 29. The protrusion 28A becomes a labyrinth seal (a minute gap) that narrows the gap 12 between the inner peripheral surface 28Ab of the flange member 24A and the shaft outer peripheral surface 10a, and prevents foreign matter from entering or purge gas from leaking.

  The gap l2 is a minute gap having a gap of, for example, several tens of μm or less, more preferably 5 μm or more and 10 μm or less. The protrusion 28B serves as a labyrinth seal that can narrow the gap 12 between the inner peripheral surface 28Bb of the flange member 24A and the shaft outer peripheral surface 10a and prevent foreign matter from entering or purge gas from leaking. The gap between the inner circumferential surface 28Bb and the shaft outer circumferential surface 10a is also a minute gap having a gap of, for example, several tens of μm or less, more preferably 5 μm or more and 10 μm or less.

  The motor 1 according to the second embodiment includes the protrusion 28A and the protrusion 28B on the inner peripheral side (rotation center Zr side) of the flange member 24A, thereby providing the flange member 24A, the protrusion 28A, and the protrusion 28B. The space 26P and the space 26Q surrounded by the shaft portion 10S and the shaft portion 10M and the first bearing device 14A are provided. The cylindrical portion 26A of the flange member 24A is provided with a second forced exhaust port 68B that opens into the space 26Q. The second forced exhaust port 68B is connected to an exhaust connector 69B attached to the cylindrical portion 26A and communicates therewith. doing. The gas a10 in the space 26Q passes through the second forced exhaust port 68B and passes through the discharge flow path A3 via the exhaust connector 69B. The pump P3 sucks the gas a10 through the discharge channel A3 and forcibly exhausts it.

  The space 26P is disposed adjacent to the space cc via the first bearing device 14A. The gap 12 is a throttle channel that increases the resistance of the channel between the space 26P and the space 26Q. The exhaust system sucked by the pump P2, that is, the first exhaust system including the forced exhaust port 68A, the exhaust connector 69A, and the outflow passage A2 to the pump P2, has a resistance in the gap 12 that is greater than the resistance of the entire first exhaust system. Is significantly larger. For this reason, when the gas a9 is forcibly sucked by the pump P2, most of the gas a9 is sucked by the pump P2 disposed in the first exhaust system having a low resistance. A slight gas gas a10 that has not passed through the space P between the protrusion 28A and the shaft outer peripheral surface 10a flows into the space 26Q without being sucked by the pump P2. The flow rate of the gas a10 is determined by the pressure difference between the space 26P and the space 26Q and the resistance of the throttle channel. The flow rate of the gas a10 is approximately proportional to the pressure difference between the space 26P and the space 26Q and inversely proportional to the resistance of the throttle channel.

The gap l3 between the protruding portion 28B and the shaft outer peripheral surface 10a is a throttle channel that divides the space 26Q and increases the resistance of the channel between the space in the chamber 51 and the space 26Q.
The exhaust system sucked by the pump P3, that is, the second exhaust system including the forced exhaust port 68B, the exhaust connector 69B, and the outflow passage A3 to the pump P2, has a resistance of the gap 13 higher than the resistance of the entire second exhaust system. Is significantly larger. For this reason, when the gas a10 is forcibly sucked by the pump P3, most of the gas a10 is sucked by the pump P3 disposed in the second exhaust system having a low resistance.

  When the inside of the chamber 51 is a high-vacuum vacuum atmosphere Va, in order to suppress the inflow of the purge gas (gas a10), a pump suitable for large-capacity exhaust is selected as the pump P2, and the gas 10a is exhausted into the pump P3. In this case, it is preferable to select a pump that can obtain a suction port pressure lower than the pressure in the space 26P. The suction port pressure is approximately proportional to the gas flow rate and inversely proportional to the gas exhaust speed. With this configuration, the pump P3 can suck the slight gas a10 that has passed through the gap l2. A seal system in which a space 26Q is provided between the space P2 having a different pressure difference and the chamber 51 and the gas 10a flowing into the space 26Q is exhausted is called a differential exhaust seal. The pressure in the space 26P is a pressure obtained by adding the pressure loss (= flow rate × resistance) accompanying the flow in the first exhaust system to the suction port pressure. The pressure in the space 26Q is a pressure obtained by adding the pressure loss (= flow rate × resistance) accompanying the flow in the second exhaust system to the suction port pressure.

  In order to suppress the flow of gas generated between the chamber 51 and the space 26P and obtain high sealing efficiency, the gap l2 between the protruding portion 28A and the shaft outer peripheral surface 10a, or the protruding portion 28B and the shaft outer peripheral surface 10a It is preferable to make the gap 13 small, for example, to be a gap of several tens of μm or less, more preferably 5 μm or more and 10 μm or less. Alternatively, in order to suppress the gas flow generated between the chamber 51 and the space 26P, the length of the protrusion 28A or the protrusion 28B in the direction parallel to the rotation center Zr is increased, thereby increasing the seal length. It is preferable to lengthen the length.

  As described above, the motor 1 according to the second embodiment includes the narrow passage 26P and the second space 26P connected to the first forced exhaust port 68A by the minute gap such as the gap l2 around the shaft portion 10S or the shaft portion 10M. A differential pressure is generated between the space 26Q connected to the forced exhaust port 68B. The motor 1 according to the second embodiment can suppress the purge gas (gas a9) from the motor 1 side into the process in the chamber 51 by including the second forced exhaust port 68B.

  As a modified example of the motor 1 of the second embodiment, when the chamber 51 is a decompressed space by supply of process gas or the like, the space a so that the gas a1 as the purge gas does not flow into the chamber 51 serving as the process chamber. In the 26P and the space 26Q, it is preferable to configure the first piping system and pump P2 and the second piping system and pump P3 described above so that the pressure in the space 26Q is higher.

  As another modification of the motor 1 of the second embodiment, in the case of a simply decompressed space where no gas is supplied into the chamber 51, the second forced exhaust port 68B opened to the space 26Q is closed or the second forced Do not open the exhaust port 68B. This structure is the same as that of the motor 1 of the first embodiment described above. Even if the gas a10 is not forcibly sucked by the pump P3, the space Q and the first forced exhaust port 68A are provided in the housing of the motor 1. A differential pressure is generated between the housing P and the space P in the housing. For this reason, the motor 1 can suppress the inflow of the gas a9 into the chamber 51.

  As described above, the flange member 24A serving as the housing includes the first forced exhaust port 68A and the second forced exhaust port 68B through which the gas is forcibly exhausted, and the first forced exhaust port 68A and the second forced exhaust port 68B are provided. A minute gap is provided as a throttle channel for narrowing the channel between the exhaust port 68B.

  A differential pressure is generated across the flow path between the first forced exhaust port 68A and the second forced exhaust port 68B, and the purge gas flowing in from the intake port 61H is other than the first forced exhaust port 68A and the second forced exhaust port 68B. The possibility of leakage into the chamber 51 can be reduced. For this reason, even if the motor 1 of the second embodiment is used in a special environment such as an environment in a high-vacuum vacuum atmosphere Va, an environment decompressed in a sealed space, or an environment containing a process gas, The possibility that the gas flowing into the special environment from the intake port 61H is released can be reduced.

(Embodiment 3)
FIG. 10 is a partial cross-sectional view schematically illustrating the configuration of the motor according to the third embodiment on a virtual plane including the rotation center. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in Embodiment 1 and Embodiment 2 mentioned above, and the overlapping description is abbreviate | omitted.

  Similar to the motor 1 of the first embodiment, the motor 1 of the third embodiment is referred to as an outer rotor type, and the motor stator 30 is disposed closer to the rotation center Zr than the motor rotor 40. Compared with the motor 1 of the second embodiment, the motor 1 of the third embodiment includes a first forced exhaust port 68A and a second forced exhaust port 68B, which are a plurality of exhaust ports, as compared with the motor 1 of the first embodiment. An elastic seal 86 is provided.

  The first forced exhaust port 68A has the same structure as the forced exhaust port 68 of the first embodiment described above, and is connected to and communicates with the exhaust connector 69A attached to the cylindrical portion 26B. The gas a9 that has passed through the first forced exhaust port 68A passes through the exhaust passage A2 via the exhaust connector 69A. The pump P2 sucks the gas a9 through the discharge channel A2 and forcibly exhausts it.

  The flange member 24B of the third embodiment is a hollow structure and includes a flange portion 27, a cylindrical portion 26B, a protruding portion 28C, and a motor housing fixing portion 29. The protruding portion 28 </ b> C positions the mounting position of the elastic body seal 86. The elastic body seal 86 is preferably a material that is called a lip seal or an O-ring and does not release outgas, and is an elastic body formed of, for example, silicon rubber or fluororubber.

  The elastic seal 86 can narrow the gap between the inner peripheral surface of the flange member 24B and the shaft outer peripheral surface 10a, and prevent foreign matter from entering or purge gas from leaking. The elastic body seal 86 includes an elastic body base 87 fixed to the inner peripheral surface of the flange member 24B, and a lip portion 88. The lip portion 88 slides on the shaft outer peripheral surface 10 a as the motor rotating body 10 rotates. The elastic body seal 86 includes two lip portions 88, but may include one lip portion 88, or may include three or more lip portions 88.

  The motor 1 according to the third embodiment includes the elastic body seals 86 and 86 on the inner peripheral side (rotation center Zr side) of the flange member 24B, so that the flange member 24B, the elastic body seals 86 and 86, the shaft portion 10S, and the like. A space 26Pa and a space 26Qa surrounded by the shaft portion 10M and the first bearing device 14A are provided. The cylindrical portion 26B of the flange member 24B has a second forced exhaust port 68B that opens to the space 26Qa. The second forced exhaust port 68B is connected to an exhaust connector 69B attached to the cylindrical portion 26B, and communicates therewith. doing. The gas a11 in the space 26Qa passes through the second forced exhaust port 68B and passes through the discharge flow path A3 via the exhaust connector 69B. The pump P3 sucks the gas a11 through the discharge passage A3 and forcibly exhausts it.

  The space 26Pa is disposed adjacent to the space cc via the first bearing device 14A. The lip portion 88 and the shaft outer peripheral surface 10a are basically slidable contact surfaces, and a slight partial gap is generated between the lip portion 88 and the shaft outer peripheral surface 10a. The gap is a throttle channel that narrows the channel between the space 26Pa and the space 26Qa. The exhaust differential pressure between the first forced exhaust port 68A and the second forced exhaust port 68B increases the resistance in the throttle channel, and the throttle channel acts as a so-called differential exhaust seal. Since the gas flowing through the gap between the lip portion 88 and the shaft outer peripheral surface 10a is suppressed, when the gas a9 and the gas a11 are forcibly sucked by the pump P2 and the pump P3, the space 26Pa and the space 26Qa are interposed. A pressure difference occurs. When the pressure of the space 26Qa is set higher than the pressure of the space 26Pa, the inflow of the gas a9 into the chamber 51 is suppressed. As described above, the motor according to the third embodiment includes the throttle channel with the small gap around the shaft portion 10S or the shaft portion 10M, and is connected to the space 26Pa connected to the first forced exhaust port 68A and the second forced exhaust port 68B. By generating a differential pressure with the space 26Qa, it is possible to suppress contamination of purge gas (gas a9) or foreign matter from the motor 1 side into the process in the chamber 51.

  As described above, in the motor 1 of the third embodiment, the flange member 24B serving as the housing includes the first forced exhaust port 68A and the second forced exhaust port 68B from which the gas a9 and the gas a11 are forcibly exhausted. The elastic body seal 86 is provided as a seal member for sealing the flow path between the first forced exhaust port 68A and the second forced exhaust port 68B.

  With this structure, a space 26Qa having a second forced exhaust port is formed between the space 26Pa having a different pressure difference and the chamber 51, an elastic seal 86 seals the space 26Qa having the second forced exhaust port 68B, and The gas a11 flowing into the space 26Qa provided with the second forced exhaust port 68B is exhausted. For this reason, even if the motor 1 of the third embodiment is used in a special environment such as an environment in a high-vacuum vacuum atmosphere Va, an environment in which pressure is reduced in a sealed space, or an environment containing a process gas, The possibility of releasing the gas a1 flowing from the intake port 61H into the special environment can be reduced.

DESCRIPTION OF SYMBOLS 1, 1B, 1C Motor 10 Motor rotating body 10A Rotating plate 10C Inner spacer 10G Shaft part gas introduction hole 10H Gas introduction path 10J Shaft part gas discharge hole 10M, 10S Shaft part 10a Shaft outer peripheral surface 14, 74 Bearing device 14A First Bearing device 14B Second bearing device 20 Motor housing 21 Housing base 21A Center protruding portion 22 Housing outer 23 Housing inner 24, 24A, 24B Flange member 25 Bearing holding member 25a Protruding portion 26, 26A, 26B Cylindrical portion 26P, 26Pa, 26Q, 26Qa, cc space 27 collar portion 28, 28A, 28B protrusion 29 motor housing fixing portion 30 motor stator 31 stator core (stator magnetic pole)
31a Teeth 31b Back yoke 32 Excitation coil 40 Motor rotor 41 Rotor yoke 42 Magnet 51 Chamber 60 Airtight sealing member 61H Air intake 61 Top plate portion 62 Body portion 63 Front flange portion 64 Fixing member 65 Sealing member 66 Inlet connector 67 Communication hole 68, 68A, 68B Forced exhaust port 69, 69A, 69B Exhaust connector 70 Angle detector 71A, 71B Resolver stator 72A, 72B Resolver rotor 81 Coupling yoke 82 Inner rotor 84 Coupling magnet 86 Elastic body seal 87 Elastic body base 88 Lip part 90 Motor control circuit l1, l2, l3 Clearance P1, P2, P3 Pump Zr Rotation center

Claims (8)

A motor stator including an exciting coil and a stator magnetic pole;
A housing for fixing the motor stator;
A motor rotor comprising a plurality of magnets opposed to the stator magnetic poles via a predetermined magnetic gap and arranged in a circumferential direction;
A bearing device that rotatably supports the motor rotor on the housing;
An airtight sealing member that is sealed so that gas in the space in which the motor stator is disposed does not flow in the space in which the motor rotor is disposed, and is disposed in the magnetic gap;
An air inlet that sucks in gas that flows through at least part of the surface of the magnet;
Including a motor.   The motor according to claim 1, wherein the intake port is provided on an extension line of a rotation center of the motor rotor.   The motor according to claim 1, wherein the housing further includes a forced exhaust port through which the gas is forcibly exhausted. The bearing device includes a first bearing device and a second bearing device separated from each other in a direction parallel to the rotation center of the motor rotor,
The motor according to claim 3, wherein the forced exhaust port is opened between the first bearing device and the second bearing device.   5. The differential pressure is generated between the space and a space in the housing through which the forced exhaust port communicates, wherein the housing includes a plurality of throttle channels that partition the space. Motor.   The housing further includes a first forced exhaust port and a second forced exhaust port through which the gas is forcibly exhausted, and a throttle that restricts a flow path between the first forced exhaust port and the second forced exhaust port. The motor according to claim 1, further comprising a flow path.   The housing further includes a first forced exhaust port and a second forced exhaust port through which the gas is forcibly exhausted, and seals a flow path between the first forced exhaust port and the second forced exhaust port. The motor according to claim 1, further comprising a seal member.   The motor according to any one of claims 1 to 7, wherein the motor rotor and a load body rotated by the motor rotor are directly connected.

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