Motor

Abstract

To provide a motor capable of suppressing outflow of generated dust to the exterior.SOLUTION: A motor has: a housing that includes a housing base and a housing shaft part; a motor stator arranged radially outside the housing shaft part; a motor rotor; a bearing that supports the motor rotor rotatably to the housing shaft part; a first seal structure that tightly seals between the motor rotor and the housing shaft part; a second seal structure that tightly seals between the motor rotor and the housing base; and a resolver that detects rotation of the motor rotor. The resolver is provided radially outside the bearing and at an opposite side to the housing base of the motor stator in a direction along a rotation central axis. The bearing has: an inner ring provided on the housing shaft part; an outer ring provided on the motor rotor; and a rolling body provided between the inner ring and the outer ring. A lubricant is enclosed between the inner ring and the outer ring.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a motor. [Background technology]

[0002] Patent Documents 1 to 3 describe motors used in a vacuum atmosphere or the like. In the motors described in Patent Documents 1 to 3, a partition wall is provided between the motor rotor and the motor stator. The partition wall separates the space in which the motor rotor is disposed from the space in which the motor stator is disposed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2006-311649 A [Patent Document 2] Patent No. 4445075 [Patent Document 3] JP 2001-339920 A Summary of the Invention [Problem to be solved by the invention]

[0004] For example, in semiconductor manufacturing processes and the like, when a motor is used in a vacuum and high-temperature environment, it is required to suppress dust and gas generation from the motor. The motor described in Patent Document 1 is a so-called outer rotor type, and the motor rotor is installed on the vacuum atmosphere side (inside the chamber). For this reason, there is a possibility that dust and gas generation from the motor rotor will flow into the vacuum atmosphere side.

[0005] In the motors of Patent Documents 2 and 3, a bearing is provided on the outer periphery of the motor rotor or the output shaft connected to the motor rotor. For this reason, the bearing is exposed to the vacuum atmosphere, and there is a possibility that dust generated from the bearing will flow into the vacuum side.

[0006] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a motor that can suppress the outflow of dust to the outside. [Means for solving the problem]

[0007] In order to achieve the above object, a motor according to one aspect of the present invention comprises a housing including a housing base and a housing shaft portion provided on the housing base and extending in a direction along a central axis of rotation, a motor stator arranged radially outside the housing shaft portion, a motor rotor provided between the motor stator and the housing shaft portion, a bearing provided radially inside the motor rotor and rotatably supporting the motor rotor on the housing shaft portion, and a seal provided on the opposite side of the bearing to the housing base in the axial direction of the motor rotor (e.g., on the output shaft 17 side in the embodiment) and sealing between the motor rotor and the housing shaft portion. The motor stator has a first seal structure, a second seal structure provided on the housing base side of the bearing in the axial direction of the motor rotor and sealing between the motor rotor and the housing base, and a resolver that detects rotation of the motor rotor, the resolver being provided radially outward from the bearing and on the opposite side of the motor stator to the housing base in the direction along the central axis of rotation (for example, on the output shaft 17 side in an embodiment), the bearing has an inner ring provided on the housing shaft portion, an outer ring provided on the motor rotor, and rolling elements provided between the inner ring and the outer ring, and a lubricant is sealed between the inner ring and the outer ring.

[0008] According to this, the bearing is provided on the radial inside of the motor rotor. A lubricant is sealed in the bearing, and the output shaft side and the housing base side of the bearing are sealed by a first seal structure and a second seal structure, respectively. In addition, the output shaft side of the motor rotor is sealed by a lid or the like during use. Therefore, it is possible to suppress dust generated in the bearing from flowing out to the outside, for example, to the vacuum atmosphere side. In addition, even if metal powder generated due to wear of the bearing goes around inside the motor, the metal powder is adsorbed to the motor stator. Therefore, the motor can suppress dust generated inside from flowing out to the outside. In addition, since the metal powder is suppressed from flowing out to the resolver side, it is possible to suppress a decrease in the detection accuracy of the resolver.

[0009] In a preferred embodiment of the motor, the inner and outer rings of the bearings are made of magnetic stainless steel, so that even if dust generated by the wear of the bearings gets inside the motor, the metal powder is effectively attracted to the permanent magnets of the motor stator and motor rotor.

[0010] In a preferred embodiment of the motor, the motor rotor has a rotor yoke and a plurality of magnets arranged along the outer periphery of the rotor yoke, the rotor yoke is disposed radially inward of the magnets, and the bearing is disposed radially inward of the rotor yoke. With this, even if metal powder generated by wear of the bearing flows out of the seal structure and into the inside of the motor, the metal powder is attracted to the magnet.

[0011] In a preferred embodiment of the motor, the bearing comprises a plurality of angular contact ball bearings arranged in a back-to-back configuration, thereby improving the rigidity of the bearing against moment loads.

[0012] In a preferred embodiment of the motor, at least one of the first seal structure and the second seal structure has a labyrinth structure formed with a gap of 0.05 mm to 0.15 mm, thereby enabling the motor to provide good non-contact sealing between the motor rotor and the housing shaft.

[0013] In a preferred embodiment of the motor, the bearing comprises a first bearing and a second bearing arranged along the axial direction, an inner ring spacer provided between the inner ring of the first bearing and the inner ring of the second bearing, and an outer ring spacer provided between the outer ring of the first bearing and the outer ring of the second bearing. With this, the first bearing and the second bearing are given a fixed position preload by the inner ring spacer and the outer ring spacer, so that the rigidity can be improved compared to a constant pressure preload. Also, the bearings are filled with a lubricant, so that the wear of the bearings is suppressed, and therefore a fixed position preload can be given well.

[0014] In a preferred embodiment of the motor, a motor partition is provided between the motor stator and the motor rotor to separate the space in which the motor stator is disposed from the space in which the motor rotor is disposed. In this manner, the motor partition can prevent gas on the atmospheric side, where the motor stator is disposed, from flowing out to the vacuum atmosphere side, where the motor rotor is disposed.

[0015] In a preferred embodiment of the motor, the resolver includes a resolver rotor connected to the motor rotor, and a resolver stator disposed radially outside the resolver rotor and having an excitation coil, and a resolver partition is provided between the resolver rotor and the resolver stator. This allows the resolver partition to separate a space in which the resolver rotor is disposed from a space in which the resolver stator is disposed, and can prevent gas on the atmospheric side where the resolver stator is disposed from flowing out to the vacuum atmosphere side where the resolver rotor is disposed. In addition, a resolver is used as an angle detector, and no electronic elements are disposed in the motor. Therefore, even when the motor is used in a high-temperature environment, the angle can be detected satisfactorily.

[0016] In a preferred embodiment of the motor, the outer diameter of the motor rotor is smaller than the outer diameter of the resolver rotor, so that the rotating structure including the motor rotor and the resolver rotor can be pulled out as a unit from the output shaft, facilitating replacement and maintenance of the bearings.

[0017] In a preferred embodiment of the motor, a connecting portion made of a magnetic material is disposed between the motor stator and the resolver in a direction along the central axis. With this, the connecting portion can shield the magnetic field generated by the motor stator, thereby improving the detection accuracy of the resolver. In addition, the connecting portion can absorb metal powder generated by wear.

[0018] In a preferred embodiment of the motor, the motor has an outer ring pressing part provided on the opposite side of the motor rotor from the housing base in the axial direction (e.g., the output shaft 17 side in the embodiment) and fixed to the outer ring of the bearing, and an inner ring pressing part provided on the opposite side of the housing shaft from the housing base in the axial direction (e.g., the output shaft 17 side in the embodiment) and fixed to the inner ring of the bearing, and the seal structure has a labyrinth structure formed by the outer ring pressing part and the inner ring pressing part. This allows dust generated from the motor due to wear of the bearing, etc., to be blocked by the seal structure and prevented from leaking out.

[0019] In a preferred embodiment of the motor, the motor stator is disposed in a space closer to the atmosphere than the space in which the motor rotor is disposed, thereby making it possible to improve the cooling efficiency of the motor stator compared to a case in which the motor stator is disposed in the same space as the motor rotor, for example in a vacuum atmosphere.

[0020] In a preferred embodiment of the motor, the motor rotor includes a samarium-cobalt permanent magnet, which prevents demagnetization even when the motor is used in a high-temperature environment, and allows the motor rotor to be rotated satisfactorily.

[0021] In a preferred embodiment of the motor, the motor control circuit supplies a drive current to the excitation coil of the motor stator based on the detection signal of the resolver. With this, the motor control circuit can constantly monitor the rotation torque and speed ripple based on the detection signal of the resolver. This makes it possible to quickly detect, for example, the occurrence of an abnormality in a bearing, or to know when to replace the bearing. Effect of the Invention

[0022] According to the present invention, it is possible to provide a motor that can suppress the outflow of dust to the outside. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is an explanatory diagram illustrating a state in which a motor according to an embodiment is used. [Diagram 2] FIG. 2 is a cross-sectional view that illustrates a schematic diagram of the motor according to the embodiment. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III' of FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of a first bearing of the motor according to the embodiment. [Diagram 5] FIG. 5 is an enlarged cross-sectional view showing a motor stator, a motor rotor, and a motor bulkhead of the motor according to the embodiment. [Figure 6] FIG. 6 is a plan view of the motor according to the embodiment as viewed from the housing base side. [Figure 7] FIG. 7 is a cross-sectional view that typically shows the first refrigerant flow path, the second refrigerant flow path, and the second throttle portion. [Figure 8] FIG. 8 is an enlarged cross-sectional view showing a resolver and a resolver partition wall of the motor according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] The present invention will be described in detail below with reference to the drawings. Note that the present invention is not limited to the following modes for carrying out the invention (hereinafter, referred to as embodiments). Furthermore, the components in the following embodiments include those that a person skilled in the art can easily imagine, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiments can be appropriately combined.

[0025] FIG. 1 is an explanatory diagram for explaining a state of use of a motor according to an embodiment. As shown in FIG. 1, a semiconductor manufacturing apparatus 100 will be described as an example of a manufacturing apparatus in which a motor 1 is used. The semiconductor manufacturing apparatus 100 includes a chamber 101, a motor 1, a motor control circuit 90, a control device 99, and a conveying device 110. The motor 1 rotates an output shaft 17 (see FIG. 2) about a rotation center axis AX. The conveying device 110 including a conveying table 111 is disposed inside the chamber 101 and is connected to the motor 1 through an opening 102. The semiconductor manufacturing apparatus 100 rotates the conveying table 111 by driving the motor 1. The semiconductor manufacturing apparatus 100 moves a workpiece (transported object) 120 in a vacuum atmosphere Va mounted on the conveying table 111. The workpiece 120 is, for example, a semiconductor substrate, a workpiece, or a tool.

[0026] The motor 1 can transmit a rotational force directly to the conveying table 111 and the workpiece 120 without using a transmission mechanism such as a gear, a belt, or a roller, and can rotate the workpiece 120. The motor 1 is a so-called direct drive motor. In this embodiment, the axial direction is the direction along the central axis of rotation AX.

[0027] The control device 99 includes an input circuit, a CPU (Central Processing Unit) which is a central processing unit, a memory which is a storage device, and an output circuit (none of which are shown). The control device 99 generates a motor rotation command i for controlling the motor 1 according to a program stored in the memory, and outputs the command to the motor control circuit 90.

[0028] When a motor rotation command i is input from the control device 99, the motor control circuit 90 outputs a drive signal from a CPU (Central Processing Unit) 91 to a three-phase amplifier (hereinafter referred to as an AMP (Amplifier) ​​92), and a drive current Mi is supplied from the AMP 92 to the motor 1. The motor 1 is driven to rotate by the drive current Mi, and rotates the conveying table 111. This moves the workpiece 120 mounted on the conveying table 111. Note that the conveying device 110 may have other members such as an arm for conveying a wafer in addition to the conveying table 111, and a configuration according to the workpiece 120 can be appropriately adopted.

[0029] When the conveyor table 111 rotates, a detection signal (resolver signal) Sr is output from an angle detector such as a resolver 60 (see FIG. 2) that detects the rotation angle. The motor control circuit 90 digitally converts the detection signal Sr using a resolver to digital converter (hereinafter referred to as an 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 workpiece 120 has reached a command position, and if the workpiece 120 has reached the command position, stops the drive signal to the AMP 92.

[0030] Furthermore, the motor control circuit 90 can constantly monitor the rotational torque and the speed ripple based on the detection signal Sr of the resolver 60. This allows the motor control circuit 90 to quickly detect the occurrence of an abnormality in the first bearing 21A and the second bearing 21B shown in Fig. 2, for example, or to know when to replace the first bearing 21A and the second bearing 21B.

[0031] In general, in the semiconductor manufacturing apparatus 100, the integration degree of semiconductors is increasing, and at the same time, the pattern width of ICs is becoming finer, leading to higher density. In order to manufacture wafers (semiconductor components) that can accommodate this fineness, a high degree of uniformity in wafer quality is required. In order to meet this demand, it is important to further reduce the impurity gas concentration in the vacuum atmosphere Va. For this reason, in the motor 1 disposed in the mounting hole (opening 102) of the chamber 101, it is also necessary to separate the space of the vacuum atmosphere Va from the external air atmosphere At.

[0032] In this embodiment, the inside of the chamber 101 is a vacuum atmosphere Va. However, the inside of the chamber 101 is not limited to a vacuum environment, and may be an atmosphere different from the atmospheric atmosphere At, such as a reduced pressure environment or an environment filled with a process gas such as nitrogen gas or a rare gas. Also, a vacuum and high temperature environment such as a diffusion furnace used in semiconductor manufacturing can be applied to the inside of the chamber 101. Also, in this embodiment, the "atmosphere side" is a space with a higher pressure than the "vacuum side" (vacuum atmosphere Va). Or, the "atmosphere side" may be a space with a lower ratio of process gas than the "vacuum side" (vacuum atmosphere Va).

[0033] FIG. 2 is a cross-sectional view showing a schematic diagram of a motor according to an embodiment. FIG. 3 is a cross-sectional view taken along line III-III' in FIG. 2. FIG. 2 is a cross-sectional view showing a motor 1 cut along a virtual plane including the central axis of rotation AX. In the following description, the direction along the central axis of rotation AX toward the output shaft 17 (vacuum atmosphere Va) may be referred to as "upper" or simply "up". Also, the direction along the central axis of rotation AX toward the housing base 11 (air atmosphere At) may be referred to as "lower" or simply "down".

[0034] 2 to 8 are exaggerated and shown in a schematic manner to facilitate understanding. For example, the motor partition 50 is shown thicker than it actually is. Furthermore, the sizes of the gap G0 and the first gap G1 to the sixth gap G6 are shown larger than they actually are, but the gap G0 and the first gap G1 to the sixth gap G6 are all formed as very small gaps.

[0035] As shown in Fig. 2, the motor 1 has a housing 10, a motor stator 30, a motor rotor 40, a first bearing 21A, a second bearing 21B, a resolver 60, a motor partition wall 50, a resolver partition wall 70, a connecting portion 15, and an output shaft 17. Note that Figs. 2 and 3 only explain the overall layout relationship of the components, and the detailed connection structure and seal structure between the components will be described later.

[0036] The housing 10 includes a housing base 11, a housing shaft portion 12, a housing outer 13, a cooling housing 14, and a cooling shaft 18. The housing base 11 is a flat plate-like member extending in a direction intersecting the rotation axis AX, and is formed in an annular shape with an opening provided at a position overlapping the rotation axis AX. The housing shaft portion 12 and the housing outer 13 are each a cylindrical member extending in a direction along the rotation axis AX (hereinafter referred to as the axial direction). The lower end of the housing shaft portion 12 is connected to the inner peripheral edge side of the housing base 11, and the lower end of the housing outer 13 is connected to the outer peripheral edge side of the housing base 11. In other words, the housing outer 13 is disposed facing the radially outer side of the housing shaft portion 12 in the radial direction. The upper end of the housing shaft portion 12 is covered by a lid portion 12a.

[0037] The cooling housing 14 is provided to cover the opening of the housing base 11. The cooling housing 14 isolates the internal space of the housing shaft portion 12 from the atmospheric atmosphere At, and prevents foreign matter from entering the internal space. The cooling housing 14 has an annular member 14a extending along the axial direction in the internal space of the housing shaft portion 12. The annular member 14a is a cylindrical member having an internal space, and the outer circumferential surface of the annular member 14a faces the inner circumferential surface of the housing shaft portion 12 with a predetermined gap (fourth gap G4 (see FIG. 5)).

[0038] The cooling shaft 18 is a columnar member provided in the internal space of the annular member 14a and extending along the rotation center axis AX. The upper end side of the cooling shaft 18 is fixed to the cover portion 12a of the housing shaft portion 12, and the lower end side of the cooling shaft 18 is fixed to the bottom portion of the cooling housing 14. The outer peripheral surface of the cooling shaft 18 faces the inner peripheral surface of the annular member 14a with a predetermined gap. That is, the annular member 14a is provided on the radial inner side of the housing shaft portion 12, and the cooling shaft 18 is provided on the radial inner side of the annular member 14a. In other words, the cooling shaft 18, the annular member 14a (cooling housing 14), and the housing shaft portion 12 are arranged in this order from the rotation center axis AX to the radial outer side.

[0039] The housing shaft portion 12 is provided radially inward of the bearings (first bearing 21A and second bearing 21B), and a first refrigerant flow path 82 and a second refrigerant flow path 83 for flowing a refrigerant are provided radially inward of the housing shaft portion 12. Specifically, the first refrigerant flow path 82 is formed between the annular member 14a and the housing shaft portion 12, which are opposed to each other in the radial direction. The first refrigerant flow path 82 is formed in an annular shape around the annular member 14a and extends in the axial direction along the annular member 14a. In addition, the second refrigerant flow path 83 is formed between the cooling shaft 18 and the annular member 14a, which are opposed to each other in the radial direction. The second refrigerant flow path 83 is formed in an annular shape around the cooling shaft 18 and extends in the axial direction along the cooling shaft 18. The first refrigerant flow path 82 and the second refrigerant flow path 83 are connected to each other at the upper end side (the side opposite to the housing base 11) of the annular member 14a. In other words, the annular member 14a is provided so as to divide the space between the cooling shaft 18 and the housing shaft portion 12 to form a first refrigerant flow path 82 and a second refrigerant flow path 83.

[0040] Further, a refrigerant supply passage 81 and a refrigerant discharge passage 84 are provided in the housing base 11 and the cooling housing 14. The refrigerant discharge passage 84 is shown by a dotted line in FIG. 2. The refrigerant supply passage 81 is connected to an external refrigerant supply device (not shown) through an opening 81a provided in the outer peripheral surface of the housing base 11. The refrigerant supply passage 81 extends radially inward from the outer peripheral surface of the housing base 11 and is connected to a lower end side (the end on the housing base 11 side) of the first refrigerant flow path 82. The refrigerant discharge passage 84 (see FIG. 6) extends radially inward from the outer peripheral surface of the housing base 11 and is connected to a lower end side of the second refrigerant flow path 83.

[0041] With this configuration, the refrigerant supply passage 81, the first refrigerant flow passage 82, the second refrigerant flow passage 83, and the refrigerant discharge passage 84 are connected to each other. A double refrigerant flow passage is formed by the first refrigerant flow passage 82 and the second refrigerant flow passage 83 on the radial inside of the bearings (first bearing 21A and second bearing 21B). As a result, the bearings (first bearing 21A and second bearing 21B) are effectively cooled by the refrigerant flowing through the refrigerant flow passage. More specifically, the refrigerant flows through the refrigerant supply passage 81, the first refrigerant flow passage 82, the second refrigerant flow passage 83, and the refrigerant discharge passage 84 in this order along the directions indicated by the arrows A1, A2, and A3. The first refrigerant flow passage 82 connected to the refrigerant supply passage 81 is provided on the radial outside, i.e., at a position close to the bearings (first bearing 21A and second bearing 21B), and the second refrigerant flow passage 83 connected to the refrigerant discharge passage 84 is provided on the radial inside, i.e., at a position away from the bearings (first bearing 21A and second bearing 21B). As a result, the bearings (first bearing 21A and second bearing 21B) are cooled in sequence by the inner ring 22, the rolling elements 24, and the outer ring 23. The refrigerant may be air-cooled or water-cooled.

[0042] Since the housing base 11, the housing shaft portion 12, and the cooling housing 14 are partially exposed to a vacuum, vacuum materials that emit less gas in a vacuum and whose emitted gas components are known, such as austenitic stainless steel and aluminum alloys, can be used. Depending on the degree of vacuum to be applied, it is more preferable to perform surface treatments such as electrolytic polishing, smoothing, and oxide coating to reduce the surface area and reduce the release of dissolved gas. In this embodiment, the housing outer 13 is exposed to the air atmosphere At and not exposed to a vacuum, so general structural materials such as cast iron and low carbon steel may be used, and stainless steel may also be used. With this structure, the motor 1 can increase the ratio of structural materials used and reduce the amount of vacuum materials used, which are more expensive than structural materials.

[0043] A motor stator 30, a motor rotor 40, a first bearing 21A, and a second bearing 21B, The motor bulkhead 50 and the connecting portion 15 are fitted between the housing shaft portion 12 and the housing outer 13 .

[0044] The motor stator 30 is disposed radially outside the housing shaft portion 12 and the motor rotor 40, and is maintained in a stationary state. Specifically, the connecting portion 15 is provided to cover the upper side (resolver 60 side) of the motor stator 30, and the motor stator 30 is fixed to the housing outer 13 via the connecting portion 15. As a method for fixing the motor stator 30, for example, the stator core 31 of the motor stator 30 is fastened to the housing 10 (housing outer 13) with a bolt. As a result, the motor stator 30, which is a non-rotating part, is positioned and fixed to the housing base 11. In addition, the motor rotor 40 is provided between the motor stator 30 and the housing shaft portion 12. The first bearing 21A and the second bearing 21B rotatably support the motor rotor 40 on the housing shaft portion 12. That is, the motor rotor 40 is disposed rotatably with respect to the motor stator 30.

[0045] As shown in Fig. 3, the motor stator 30, the motor rotor 40, the first bearing 21A (not shown in Fig. 3), and the second bearing 21B are all annular structures and are arranged concentrically around the rotation axis AX. From the housing shaft portion 12, the bearings (first bearing 21A and second bearing 21B), the motor rotor 40, the motor bulkhead 50, the motor stator 30, and the housing outer 13 are arranged in this order from the housing shaft portion 12 toward the outside in the radial direction. In other words, the motor 1 is a so-called inner rotor type, and the motor rotor 40 is located closer to the rotation axis AX than the motor stator 30. In other words, the motor rotor 40 is arranged on the vacuum atmosphere Va side, and the motor stator 30 is arranged on the air atmosphere At side.

[0046] The motor stator 30 is formed by overlapping electromagnetic steel sheets, and includes a stator core 31, an insulator 34 (see FIG. 2), and an excitation coil 35 (see FIG. 2). The motor stator 30 is formed, for example, by bonding steel sheets or by in-die crimping. This makes it easy to process the stator core 31, and good magnetic characteristics of the motor stator 30 can be obtained. The stator core 31 has a back yoke 32 and teeth 33. The back yoke 32 is an annular member and is arranged facing the inner peripheral surface of the housing outer 13 with a space therebetween. A plurality of teeth 33 are arranged in the circumferential direction on the back yoke 32, and are arranged at equal intervals. The teeth 33 each protrude radially inward from the back yoke 32. The motor stator 30 is not limited to such an integral core, and may be a split core in which a plurality of split stator cores 31 are arranged. The excitation coils 35 are wound around the teeth 33 of the stator core 31 via the insulators 34. A wiring for supplying electric power from a power source is connected to the motor stator 30, and a driving current Mi is supplied from the motor control circuit 90 to the exciting coil 35 through this wiring.

[0047] The motor windings and insulator 34 (insulating material) constituting the excitation coil 35 shown in Fig. 2 are both made of heat-resistant materials. The motor windings and insulator 34 (insulating material) have a heat resistance of, for example, 200°C or higher. This allows the motor 1 to operate satisfactorily in a high-temperature environment. The motor windings are coated with, for example, polyimide. The material of the insulator 34 is, for example, insulating paper, or a resin material, or a combination of insulating paper and a resin material.

[0048] The motor rotor 40 includes a rotor yoke 41, a magnet 42, and a space 43 (see FIG. 2). The rotor yoke 41 is a cylindrical member, and the outer diameter of the rotor yoke 41 is smaller than the inner diameter of the stator core 31. The motor rotor 40 is provided in an annular shape on the radially inner side of the motor stator 30 with a gap that becomes a magnetic gap MG. The rotor yoke 41 is formed of low carbon steel, which is a ferromagnetic material, and it is preferable that the surface is nickel plated. By applying nickel plating, the rotor yoke 41 can be prevented from rusting and outgassing can be reduced.

[0049] As shown in FIG. 3, the magnets 42 are attached along the outer periphery of the rotor yoke 41. That is, the motor stator 30 (stator core 31) is disposed radially outside the magnets 42 via the motor bulkhead 50. Since the rotating motor rotor 40 and the motor stator 30, which is a non-rotating part, are disposed without contact with each other, it is possible to suppress the generation of foreign matter. The magnets 42 are disposed such that the south poles and north poles are alternately disposed at equal intervals in the circumferential direction of the rotor yoke 41. The number of poles of the motor rotor 40 is, for example, 20 poles. 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 a 20-pole, 18-slot configuration, and can be appropriately changed as necessary.

[0050] In this embodiment, it is preferable to use a samarium-cobalt permanent magnet for the magnet 42. This prevents demagnetization even when the motor 1 is used in a high-temperature environment, and allows the motor rotor 40 to be rotated satisfactorily. However, the magnet 42 is not limited to this, and other materials such as a neodymium magnet may be used.

[0051] 2 is a space that prevents magnetic flux from flowing around the end face of the magnet 42. The step dimension Y (see FIG. 4) of the rotor yoke 41 that forms the space 43 is preferably about 1 / 3 to 1 / 2 of the thickness dimension X (see FIG. 4) of the magnet 42. If this range is exceeded, magnetic flux will flow around the upper end face of the magnet 42 of the motor rotor 40, preventing the magnetic flux from flowing around the stator core 31, resulting in a decrease in output torque.

[0052] The motor partition 50 is provided in the magnetic gap MG between the motor stator 30 and the motor rotor 40, and separates the space in which the motor rotor 40 is disposed (vacuum atmosphere Va side) from the space in which the motor stator 30 is disposed (air atmosphere At side). A detailed configuration of the motor partition 50 will be described later.

[0053] An output shaft 17 is connected to the upper end of the rotor yoke 41. The output shaft 17 rotates together with the rotor yoke 41, and transmits the torque of the motor 1 to the outside (for example, the conveyor table 111).

[0054] The first bearing 21A and the second bearing 21B are provided between the outer periphery of the housing shaft portion 12 and the inner periphery of the rotor yoke 41. The first bearing 21A and the second bearing 21B are angular ball bearings, and are arranged in a back-to-back combination. The first bearing 21A and the second bearing 21B are rolling bearings having an inner ring 22, an outer ring 23, and a rolling element 24. The rolling element 24 is provided between the inner ring 22 and the outer ring 23. In the direction along the rotation center axis AX, the first bearing 21A is disposed on the output shaft 17 side, and the second bearing 21B is disposed on the housing base 11 side. The inner ring 22 of the first bearing 21A and the inner ring 22 of the second bearing 21B are fixed to the housing shaft portion 12. The outer ring 23 of the first bearing 21A and the outer ring 23 of the second bearing 21B are fixed to the rotor yoke 41 of the motor rotor 40. The first bearing 21A and the second bearing 21B are each a bearing in which a lubricant such as grease (not shown) is enclosed between the outer ring 23 and the inner ring 22. The lubricant used is vacuum grease (e.g., fluorine-based grease) that can be used even at high temperatures.

[0055] An inner ring spacer 25 is provided between the inner ring 22 of the first bearing 21A and the inner ring 22 of the second bearing 21B. An outer ring spacer 26 is provided between the outer ring 23 of the first bearing 21A and the outer ring 23 of the second bearing 21B. This defines the positions of the first bearing 21A and the second bearing 21B in the axial direction. An inner ring holder 16 is connected to the upper end (the end opposite the housing base 11 in the axial direction) of the housing shaft portion 12, and the position of the upper end of the inner ring 22 of the first bearing 21A is fixed by the inner ring holder 16. The output shaft 17 also serves as the outer ring holder, and the position of the upper end of the outer ring 23 of the first bearing 21A is fixed by the output shaft 17.

[0056] The lower end of the inner ring 22 of the second bearing 21B is fixed to the housing base 11. Also, the lower end of the outer ring 23 of the second bearing 21B is fixed to the rotor yoke 41. With this configuration, the first bearing 21A, the spacers (the inner ring spacer 25 and the outer ring spacer 26), and the second bearing 21B are positioned so that no gap (backlash) occurs in the axial direction, forming a rotation support structure of a fixed position preload type. Since the first bearing 21A and the second bearing 21B are given a fixed position preload by the inner ring spacer 25 and the outer ring spacer 26, the rigidity can be improved compared to a fixed pressure preload described later. Also, since the first bearing 21A and the second bearing 21B are arranged in a back-to-back combination, the rigidity against moment loads can be improved. Also, the first bearing 21A and the second bearing 21B are filled with a lubricant, and wear is suppressed. As a result, no gap (backlash) occurs in the axial direction of the first bearing 21A and the second bearing 21B due to wear, so that the inner ring spacer 25 and the outer ring spacer 26 can impart a fixed position preload more satisfactorily.

[0057] A first seal structure LS1 is provided on the output shaft 17 side of the motor rotor 40 (the side opposite to the housing base 11 in the axial direction) to seal between the motor rotor 40 and the housing shaft portion 12 without contact. More specifically, the first seal structure LS1 is formed of a minute gap formed between the output shaft 17 and the inner ring pressing portion 16 on the output shaft 17 side of the first bearing 21A. In addition, a second seal structure LS2 is provided on the housing base 11 side of the second bearing 21B to seal between the motor rotor 40 and the housing shaft portion 12 without contact. As a result, the output shaft 17 side and the housing base 11 side of the first bearing 21A and the second bearing 21B are sealed by the first seal structure LS1 and the second seal structure LS2, respectively. The motor 1 can suppress dust generated due to wear of the first bearing 21A and the second bearing 21B from flowing out to the vacuum atmosphere Va side by the first seal structure LS1 and the second seal structure LS2.

[0058] Furthermore, the inner ring 22 and the outer ring 23 of the first bearing 21A and the second bearing 21B are made of a magnetic iron-based material. The magnetic iron-based material is, for example, martensitic stainless steel. With this, even if dust (metal powder) generated by wear of the bearings (first bearing 21A and second bearing 21B) gets inside the motor 1, it is attracted to the magnet 42 of the motor rotor 40 and the motor bulkhead 50 (the magnetic force of the motor stator 30 acts through a wall portion 51 (see FIG. 5 described later)).

[0059] The rolling elements 24 can be made of the same material as the inner ring 22 and the outer ring 23, such as martensitic stainless steel. Alternatively, the inner ring 22 and the outer ring 23 may be made of ceramics. Examples of ceramic materials used for the inner ring 22 and the outer ring 23 include silicon nitride, zirconia, and alumina. This can suppress dust generation due to wear from the rolling elements 24 of the first bearing 21A and the second bearing 21B, and gas generation in a high-temperature environment.

[0060] The resolver 60 is provided radially outward of the first bearing 21A and the second bearing 21B and axially closer to the output shaft 17 than the motor stator 30. The resolver 60 is an angle detector that detects the rotation of the motor rotor 40.

[0061] The resolver 60 includes resolver stators 61A, 61B and resolver rotors 62A, 62B. The resolver rotors 62A, 62B are disposed opposite the resolver stators 61A, 61B across a predetermined gap, and are rotatable relative to the resolver stators 61A, 61B. Specifically, the resolver stators 61A, 61B are fixed to the housing outer 13. As a result, the resolver stators 61A, 61B are positioned and fixed relative to the motor stator 30 and the housing base 11, and are maintained in a stationary state. The resolver rotors 62A, 62B are fixed to the outer periphery of the output shaft 17. The resolver rotors 62A, 62B rotate together with the motor rotor 40.

[0062] A resolver partition 70 is provided between the resolver rotors 62A, 62B and the resolver stators 61A, 61B. The resolver partition 70 is provided to cover the resolver stators 61A, 61B. The resolver partition 70 also serves as an attachment structure for the chamber 101 (see FIG. 1), and is fixed to the chamber 101 at a portion that protrudes radially outward beyond the housing outer 13. A groove 70b is provided in a partition upper surface 70a of the resolver partition 70. The groove 70b is formed in an annular shape centered on the central axis of rotation AX. A sealing member (not shown), such as an O-ring, fitted into the groove 70b provides a seal between the partition upper surface 70a and the chamber 101.

[0063] With the above-mentioned configuration, the motor stator 30 is disposed closer to the atmospheric atmosphere At than the motor rotor 40. The bearings (the first bearing 21A and the second bearing 21B) are disposed radially inside the motor rotor 40. More specifically, the rotor yoke 41 is disposed radially inside the magnet 42, and the bearings (the first bearing 21A and the second bearing 21B) are disposed radially inside the rotor yoke 41. The resolver 60 is disposed axially closer to the output shaft 17 than the motor stator 30. The output shaft 17 side of the motor rotor 40 in the axial direction is sealed with a lid or the like during use, so that dust generated in the bearing can be prevented from flowing out to the outside (to the vacuum atmosphere Va side). Even if metal powder generated due to wear of the bearing goes around inside the motor 1, the metal powder is attracted to the magnet 42 and the motor bulkhead 50 (where the magnetic force of the motor stator 30 acts through the wall 51). Therefore, the motor 1 can prevent dust generated inside from flowing out to the outside.

[0064] In addition, the housing 10 is provided with an exhaust port 80 that is connected to the outside. This allows gas in the space in which the motor stator 30 is arranged to be exhausted to the outside, improving the cooling efficiency of the motor stator 30. In addition, as shown in FIG. 2, the outer diameter of the motor rotor 40 is smaller than the outer diameter of the resolver rotors 62A, 62B. Therefore, the rotating structure including the motor rotor 40 and the resolver rotors 62A, 62B can be pulled out as a unit from the output shaft 17 side simply by removing the inner ring retaining portion 16 from the housing shaft portion 12. This makes it easy to replace or maintain the bearings (first bearing 21A and second bearing 21B).

[0065] Next, the detailed structure of each component of the motor 1 will be described. FIG. 4 is an enlarged cross-sectional view of the first bearing of the motor according to the embodiment. As shown in FIG. 4, the inner ring pressing portion 16 is fixed to the upper end of the housing shaft portion 12 by a bolt BT1. The inner ring pressing portion 16 is an annular member having an opening that is connected to the internal space SP. However, the inner ring pressing portion 16 may be a flat plate that covers the internal space SP. A step portion 16a is formed on the outer periphery of the inner ring pressing portion 16 at a portion that protrudes radially outward from the housing shaft portion 12. The upper end of the inner ring 22 of the first bearing 21A contacts the step portion 16a. The lower end of the inner ring 22 of the first bearing 21A contacts the inner ring spacer 25. The inner ring 22 of the first bearing 21A is positioned in the axial direction by being sandwiched between the step portion 16a and the inner ring spacer 25.

[0066] The output shaft 17 is fixed to the upper end of the rotor yoke 41 of the motor rotor 40 by a bolt BT2. A protruding portion 41d protruding in the axial direction is provided at the upper end (the end opposite to the housing base 11 in the axial direction) of the rotor yoke 41. The protruding portion 41d is an annular member provided along the outer periphery of the rotor yoke 41, and is formed to have a width smaller than the width of the rotor yoke 41 in the radial direction. The output shaft 17 is fixed to the radial inside of the protruding portion 41d. That is, the output shaft 17 and the rotor yoke 41 are fixed by a so-called spigot joint. For this reason, the positioning of the output shaft 17 can be easily performed when replacing or maintaining the bearings (the first bearing 21A and the second bearing 21B). In addition, it is preferable that the output shaft 17 is made of a material having a thermal expansion coefficient larger than those of the rotor yoke 41 and the protruding portion 41d. This makes it possible to suppress the positional deviation of the output shaft 17 when the motor 1 is used in a high-temperature environment.

[0067] A step portion 17b is formed on the output shaft 17 at a portion that protrudes radially inward beyond the inner circumferential surface of the rotor yoke 41. An upper end of the outer ring 23 of the first bearing 21A contacts the step portion 17b. A lower end of the outer ring 23 of the first bearing 21A contacts the outer ring spacer 26. The outer ring 23 of the first bearing 21A is positioned in the axial direction by being sandwiched between the step portion 17b and the outer ring spacer 26.

[0068] The output shaft 17 further has a flange portion 17a. The flange portion 17a is an annular member extending radially inward from the inner peripheral surface of the output shaft 17. The flange portion 17a is provided so as to cover the space between the inner ring 22 and the outer ring 23 of the first bearing 21A. The inner peripheral surface of the flange portion 17a is disposed opposite the outer peripheral surface of the inner ring pressing portion 16 with a gap G0 therebetween, thereby forming a first seal structure LS1. The gap G0 constituting the first seal structure LS1 is formed, for example, to be about 0.05 mm or more and 0.15 mm or less. The first seal structure LS1 preferably employs a labyrinth structure. The labyrinth structure may have any configuration, but for example, a groove portion may be formed at a position opposite the flange portion 17a of the inner ring pressing portion 16, and the gap G0 may be formed to be approximately C-shaped in cross section.

[0069] The output shaft 17 also serves as a support structure for the resolver rotors 62A, 62B. That is, the output shaft 17 has a protruding portion 17d that protrudes radially outward beyond the motor rotor 40, and a step portion 17c is formed by a portion fixed to the motor rotor 40 and the protruding portion 17d. The resolver rotors 62A, 62B are incorporated into the step portion 17c and fixed with bolts BT3. With this structure, the resolver rotors 62A, 62B rotate integrally with the output shaft 17 and the motor rotor 40.

[0070] 5 is an enlarged cross-sectional view of the motor stator, motor rotor, and motor bulkhead of the motor according to the embodiment. The cooling housing 14 of the housing 10 is fixed to the housing base 11 with bolts BT4. The cooling housing 14 has a sealing member SL1 such as an O-ring that seals the gap between the upper surface of the cooling housing 14 and the lower surface of the housing base 11.

[0071] The housing outer 13 is fixed to the outer edge side of the housing base 11 with bolts BT5. A plurality of steps 11a, 11b, 11c, 11d, and 11e are formed on the upper surface of the housing base 11 between the housing shaft portion 12 and the housing outer 13. The steps 11a, 11b, 11c, 11d, and 11e are provided in this order from the housing shaft portion 12 toward the outside in the radial direction, and the heights of the upper surfaces decrease in the order of the steps 11a, 11b, 11c, 11d, and 11e.

[0072] The lower end of the inner ring 22 of the second bearing 21B contacts the upper surface of the step portion 11a. The upper end of the inner ring 22 of the second bearing 21B contacts the inner ring spacer 25. The inner ring 22 of the second bearing 21B is sandwiched between the step portion 11a and the inner ring spacer 25 to fix its axial position. A flange portion 41a protruding radially inward from the inner peripheral surface is formed on the lower end side of the rotor yoke 41. The lower end of the outer ring 23 of the second bearing 21B contacts the upper surface of the flange portion 41a. The upper end of the outer ring 23 of the second bearing 21B contacts the outer ring spacer 26. The outer ring 23 of the second bearing 21B is sandwiched between the flange portion 41a and the outer ring spacer 26 to fix its axial position. In addition, since the housing base 11 is formed with steps 11b and 11c, the outer ring 23 of the second bearing 21B and the lower end side of the rotor yoke 41 are provided without contacting the housing base 11. The second seal structure LS2 is constituted by a minute gap formed between the steps 11b and 11c of the housing base 11 and the lower end side of the rotor yoke 41. The minute gap constituting the second seal structure LS2 is formed, for example, to be about 0.05 mm or more and 0.15 mm or less. It is preferable that the second seal structure LS2 adopts a labyrinth structure. In addition, the upper end of the magnet 42 is in contact with the step 41b formed on the outer periphery of the rotor yoke 41 to be positioned.

[0073] Next, a detailed configuration of the motor partition 50 will be described. As shown in Fig. 5, the motor partition 50 has a wall portion 51, a top plate portion 52, and a flange portion 53. The motor partition 50 is a partition that seals the space in which the motor stator 30 is arranged (on the air atmosphere At side) so that gas does not flow into the space in which the motor rotor 40 is arranged (on the vacuum atmosphere Va side).

[0074] Specifically, the wall portion 51 of the motor partition wall 50 is a cylindrical member extending in the axial direction and is disposed between the stator core 31 and the magnet 42 fixed to the rotor yoke 41. The wall portion 51 faces the outer periphery of the magnet 42 with a first gap G1 therebetween. In other words, the first gap G1 is a gap formed between the motor partition wall 50 and the motor rotor 40 in the radial direction. The thickness of the wall portion 51 in the radial direction is 40% or more and 80% or less of the length of the gap between the stator core 31 and the magnet 42 fixed to the rotor yoke 41. This can improve the strength of the motor partition wall 50 and suppress deformation of the motor partition wall 50. In addition, contact between the motor partition wall 50 and the motor rotor 40, which is a rotating part, can be suppressed.

[0075] The top plate portion 52 is connected to an upper end side of the wall portion 51 and extends radially outward. The top plate portion 52 is provided to cover at least a portion of the motor stator 30. In other words, the top plate portion 52 is disposed closer to the output shaft 17 than the stator core 31, the insulator 34, and the excitation coil 35 in the axial direction.

[0076] The connecting portion 15 is provided to cover the upper surface and the radial outer side of the top plate portion 52. Specifically, the connecting portion 15 has a connecting top plate portion 15a and a connecting wall portion 15b. The connecting wall portion 15b is a cylindrical member, extends along the axial direction, and is disposed between the inner circumferential surface of the housing outer 13 and the outer circumferential surface of the insulator 34 and the top plate portion 52. The connecting top plate portion 15a is connected to the upper end side of the connecting wall portion 15b and extends radially inward. The connecting top plate portion 15a is provided to overlap with the top plate portion 52 of the motor partition wall 50.

[0077] A flange portion 13a extending radially inward is provided on the inner circumferential surface of the housing outer 13. The upper end of the connecting wall portion 15b is fixed to the lower surface of the flange portion 13a with bolts BT6. Furthermore, the stator core 31 of the motor stator 30 is fixed to the lower end of the connecting wall portion 15b with bolts BT7. With this configuration, the motor stator 30 is fixed to the housing outer 13 of the housing 10 via the connecting portion 15.

[0078] A portion of the inner peripheral surface 15c side of the connecting top plate portion 15a overlaps with the top plate portion 52. The top plate portion 52 is fixed to the connecting top plate portion 15a with bolts BT8. As a result, the top plate portion 52 is fixed to the housing outer 13 via the connecting portion 15. In addition, the gap between the lower surface of the connecting top plate portion 15a and the upper surface of the top plate portion 52 is sealed with a sealing member SL3 such as an O-ring.

[0079] Also, the inner peripheral surface 15c of the connecting top plate portion 15a is provided facing the outer peripheral surface 41c of the rotor yoke 41 with a third gap G3. The size of the third gap G3 is smaller than the size of the first gap G1. This makes it possible to prevent dust generated due to wear of the first bearing 21A and the second bearing 21B from flowing through the third gap G3 to the resolver 60 side. Also, as described above, the connecting portion 15 is fixed and positioned on the housing outer 13, and this makes it possible to ensure the distance (third gap G3) between the rotor yoke 41 of the motor rotor 40 and the connecting portion 15 within a predetermined range.

[0080] The flange portion 53 of the motor partition wall 50 is connected to the lower end side of the wall portion 51 and extends radially inward. The flange portion 53 is fixed to the upper surface of the step portion 11d of the housing base 11 by a bolt BT9. A sealing member SL2 such as an O-ring seals the gap between the lower surface of the flange portion 53 and the upper surface of the step portion 11d. With this configuration, the space surrounded by the motor partition wall 50, the housing base 11, the housing outer 13, and the connecting portion 15 is sealed. The motor stator 30 is provided in the space surrounded by the motor partition wall 50, the housing base 11, the housing outer 13, and the connecting portion 15. The motor rotor 40 and the bearings (the first bearing 21A and the second bearing 21B) are provided in the space surrounded by the motor partition wall 50, the housing base 11, the housing shaft portion 12, and the output shaft 17. This can improve the positioning accuracy of each component and the rigidity of the motor 1.

[0081] A non-magnetic material is used for the motor partition 50. For example, austenitic stainless steel is suitable as the material for the motor partition 50. Therefore, it is possible to suppress the decrease in the magnetic field when the motor rotor 40 is driven through the wall portion 51. The motor partition 50 can be formed as a cylindrical integral molding by, for example, applying deep drawing to a non-magnetic stainless steel plate. The wall portion 51 is formed thinner than the top plate portion 52 and the flange portion 53. Specifically, while the top plate portion 52 and the flange portion 53 have a thickness of several mm, the wall portion 51 is stretched to a thickness of 0.2 mm to 0.5 mm. This makes it possible to suppress magnetic loss when driving the motor rotor 40 while ensuring the rigidity and airtightness of the motor partition 50. In addition, since the first gap G1 is small, it is possible to improve the magnetic coupling between the motor stator 30 and the motor rotor 40, and it is possible to rotate and drive the motor rotor 40 well.

[0082] The connecting portion 15 is made of a magnetic material. The connecting portion 15 is a soft magnetic material, and is made of, for example, low carbon steel with a carbon concentration of 0.48% or less. An example of low carbon steel is S45C defined by the JIS standard. Therefore, the connecting portion 15 functions as a shield and can prevent the magnetic field generated from the motor stator 30 from reaching the resolver 60. Note that a part of the connecting portion 15 (the inner peripheral surface 15c of the connecting top plate portion 15a) is exposed to the vacuum atmosphere Va, so it is preferable to use the same material as the rotor yoke 41 of the motor rotor 40.

[0083] More specifically, a third gap G3 between inner peripheral surface 15c of connecting portion 15 and outer peripheral surface 41c of rotor yoke 41 in the radial direction is about 0.1 mm or more and 0.4 mm or less. The length of third gap G3 between inner peripheral surface 15c of connecting portion 15 and outer peripheral surface 41c of rotor yoke 41 in the direction along the central axis of rotation is about 1 mm or more and 4 mm or less. Furthermore, the thickness of a portion of connecting portion 15 facing rotor yoke 41 is 1 mm or more. Here, the thickness is the thickness of connecting portion 15 on the radial inner side (rotor yoke 41 side) of bolt BT10 (see FIG. 8).

[0084] With this configuration, a magnetic circuit is formed in which the magnetic field generated from the motor stator 30 passes through the rotor yoke 41, the third gap G3, and the connecting portion 15 and returns to the motor stator 30. This makes it possible to prevent the magnetic field generated by the drive current Mi flowing through the excitation coil 35 from propagating through the motor rotor 40 and reaching the resolver 60. As a result, the motor 1 can prevent erroneous detection of the position information of the resolver 60.

[0085] With the above-mentioned configuration, even if metal powder is generated due to wear of the first bearing 21A and the second bearing 21B, the first seal structure LS1 (see FIG. 4) provided on the output shaft side of the first bearing 21A and the second seal structure LS2 (see FIG. 5) provided on the housing base 11 side of the second bearing 21B can prevent the metal powder from flowing out to the vacuum atmosphere Va. Even if the metal powder gets into the motor 1 from the lower side (housing base 11 side) of the second bearing 21B, it is attracted to the motor bulkhead 50 (where the magnetic force generated from the motor stator 30 acts through the wall 51 (see FIG. 5)) or the connecting portion 15 (where the magnetic force generated from the motor stator 30 acts), so that it is possible to prevent the metal powder from flowing out to the outside.

[0086] Next, the detailed configuration of the first refrigerant flow path 82 and the second refrigerant flow path 83 will be described with reference to Fig. 5 to Fig. 7. Fig. 6 is a plan view of the motor according to the embodiment, seen from the housing base side. Fig. 7 is a cross-sectional view showing the first refrigerant flow path, the second refrigerant flow path, and the second throttle portion. Fig. 7 is a cross-sectional view taken along line VII-VII' in Fig. 2, and omits the configuration radially outward from the housing shaft portion 12.

[0087] As shown in FIG. 5, the width of the fourth gap G4 in the radial direction of the first refrigerant flow path 82, i.e., the size of the gap in the radial direction between the annular member 14a and the housing shaft portion 12, is, for example, about 0.5 mm or more and 1.5 mm or less. The gap in the radial direction of the second refrigerant flow path 83 is also formed to be about the same size as the fourth gap G4. That is, the size of the gap in the radial direction between the annular member 14a and the cooling shaft 18 is, for example, about 0.5 mm or more and 1.5 mm or less. In the example shown in FIG. 5, the gap in the radial direction of the second refrigerant flow path 83 is formed to be larger than the fourth gap G4 in the radial direction of the first refrigerant flow path 82. With this configuration, the flow rate and pressure of the refrigerant flowing through the first refrigerant flow path 82 and the second refrigerant flow path 83 can be set to appropriate values.

[0088] A first reservoir 82T is provided at the lower end of the first refrigerant flow passage 82, that is, at the position where the refrigerant supply passage 81 (see FIG. 6) is connected. The first reservoir 82T is formed in an annular shape on the outer periphery of the annular member 14a. The size of the fifth gap G5 in the radial direction of the first reservoir 82T is about three to five times the size of the fourth gap G4. The length of the first reservoir 82T in the axial direction is about three to five times the size of the fourth gap G4. As a result, the refrigerant supplied from the refrigerant supply passage 81 is accumulated around the annular member 14a in the first reservoir 82T, and then flows into the first refrigerant flow passage 82 in a gap smaller than the first reservoir 82T. As a result, it is possible to suppress the variation in the pressure distribution of the refrigerant in the circumferential direction of the first refrigerant flow passage 82.

[0089] At the upper end side of the first refrigerant flow path 82, i.e., the end on the side where the cover portion 12a is provided, protrusions 14b are provided that protrude radially outward from the outer circumferential surface of the annular member 14a. A plurality of protrusions 14b are arranged along the circumferential direction of the annular member 14a. A first throttle portion 82S is formed between the plurality of protrusions 14b and the inner circumferential surface of the housing shaft portion 12.

[0090] At the upper end side of the second refrigerant flow passage 83, i.e., at the end on the side where the lid portion 12a is provided, a protrusion 18c is provided that protrudes radially outward from the outer circumferential surface of the cooling shaft 18. A plurality of protrusions 18c are arranged along the circumferential direction of the cooling shaft 18. As shown in FIG. 7, each of the plurality of protrusions 18c has a substantially triangular shape, and six of the protrusions 18c are arranged side by side in the circumferential direction to form a hexagon as a whole. In the example shown in FIG. 7, the cooling shaft 18 is provided inscribed in the hexagon formed by the six protrusions 18c. A second throttling portion 83S is formed between the plurality of protrusions 18c and the inner circumferential surface of the annular member 14a.

[0091] The plurality of protruding portions 14b in the first refrigerant flow passage 82 shown in FIG. 5 may have the same configuration as the plurality of protruding portions 18c shown in FIG. 7. The first throttling portion 82S and the second throttling portion 83S are provided at a position where the refrigerant flows from the first refrigerant flow passage 82 through the upper end side of the annular member 14a and turns back to the second refrigerant flow passage 83. This makes it possible to suppress the variation in pressure distribution of the refrigerant that turns back from the first refrigerant flow passage 82 and flows into the second refrigerant flow passage 83. The plurality of protruding portions 14b, 18c are each triangular in shape, but are not limited thereto. The shape and number of the plurality of protruding portions 14b, 18c may be appropriately changed, and may be formed into a quadrangular shape and arranged at a distance in the circumferential direction, for example. The first throttling portion 82S and the second throttling portion 83S are not limited to a configuration in which both are provided, and it is sufficient that at least one of them is provided.

[0092] Returning to FIG. 5, the protrusion 18a provided at the upper end of the cooling shaft 18 is fitted into a recess provided in the lid portion 12a. The protrusion 18b provided at the lower end of the cooling shaft 18 is fitted into a recess provided in the cooling housing 14. This allows the cooling shaft 18 to be positioned in the axial and radial directions. Meanwhile, the lower end side (cooling housing 14) of the annular member 14a is fixed to the housing base 11 with a bolt BT4, and the upper end side of the annular member 14a is disposed with a gap between it and the housing shaft portion 12, the lid portion 12a, and the cooling shaft 18. This forms a flow path for the refrigerant. Even in this case, since the multiple protrusions 14b and the multiple protrusions 18c are provided, it is possible to suppress the radial positional deviation of the upper end side of the annular member 14a.

[0093] A second reservoir 83T is provided at the lower end of the second refrigerant flow path 83, that is, at the position where the refrigerant discharge passage 84 (see FIG. 6) is connected. The second reservoir 83T is formed in an annular shape on the inner circumference of the annular member 14a. The size of the sixth gap G6 in the radial direction of the second reservoir 83T is about three to six times the gap in the radial direction of the second refrigerant flow path 83. The length of the second reservoir 83T in the axial direction is about three to six times the gap in the radial direction of the second refrigerant flow path 83. As a result, the refrigerant flowing through the second refrigerant flow path 83 is accumulated between the annular member 14a and the cooling shaft 18 in the second reservoir 83T, and then flows into the refrigerant discharge passage 84, which is a gap smaller than the second reservoir 83T, and is discharged to an external refrigerant supply device. As a result, it is possible to suppress the variation in the pressure distribution of the refrigerant in the second refrigerant flow path 83. It is to be noted that either the first accumulation portion 82T or the second accumulation portion 83T does not necessarily have to be provided.

[0094] With this configuration, the bearings (first bearing 21A and second bearing 21B) are effectively cooled by the refrigerant flowing through the first refrigerant flow path 82 and the second refrigerant flow path 83. Therefore, even when the motor 1 is used in a high-temperature environment, deterioration of the lubricant in the bearings can be suppressed, and wear of the bearings can be suppressed. Furthermore, the first refrigerant flow path 82 and the second refrigerant flow path 83 are disposed in a space closer to the atmosphere than the housing base 11, the housing shaft portion 12, and the lid portion 12a. This makes it possible to suppress contamination of the vacuum atmosphere Va by the refrigerant flowing through the first refrigerant flow path 82 and the second refrigerant flow path 83.

[0095] Next, the configuration of the resolver 60 will be described. Fig. 8 is an enlarged cross-sectional view of the resolver and the resolver partition wall of the motor according to the embodiment. As shown in Fig. 8, the resolver stators 61A and 61B are fixed to the upper surface of the flange portion 13a of the housing outer 13 by bolts BT12.

[0096] The resolver stators 61A and 61B have an annular laminated core with a plurality of stator poles formed at equal intervals in the circumferential direction, and a resolver coil is wound around each of the stator poles. A wire for outputting a detection signal (resolver signal) Sr is connected to each resolver coil.

[0097] The resolver rotors 62A, 62B are formed of hollow annular laminated iron cores, and are fixed to the outer stepped portion 17c of the output shaft 17. The location of the resolver 60 is not particularly limited as long as it is closer to the output shaft 17 than the motor stator 30 in the axial direction, and the location is capable of detecting the rotation of the motor rotor 40 (output shaft 17).

[0098] A motor control circuit 90 (see FIG. 1) that controls the motor 1 supplies a drive current Mi to the excitation coil 35 of the motor stator 30 based on the detection signal Sr of the resolver 60. Specifically, when the motor rotor 40 rotates, the output shaft 17 rotates together with the motor rotor 40, and the resolver rotors 62A, 62B also rotate in conjunction with the motor rotor 40. This causes the reluctance between the resolver rotors 62A, 62B and the resolver stators 61A, 61B to change continuously. The resolver stators 61A, 61B detect the change in reluctance and convert the detection signal Sr into a digital signal by the RDC 93. A CPU 91 of the motor control circuit 90 that controls the motor 1 can calculate and process the positions and rotation angles of the output shaft 17 and the motor rotor 40 that are linked to the resolver rotors 62A, 62B per unit time based on the electrical signal of the RDC 93. As a result, the motor control circuit 90 is able to measure the rotation state of the output shaft 17 (for example, the rotation speed, the rotation direction, or the rotation angle, etc.).

[0099] The resolver partition wall 70 has an inner wall portion 71, a resolver top plate portion 72, an attachment portion 73, and a flange portion 74. The inner wall portion 71 is a cylindrical member extending in the axial direction, and is provided between the resolver stators 61A, 61B and the resolver rotors 62A, 62B in the radial direction.

[0100] The resolver top plate portion 72 is connected to an upper end of the inner wall portion 71 and extends radially outward. The resolver top plate portion 72 is provided to cover the resolver stators 61A, 61B. The upper surface of the resolver top plate portion 72 becomes the partition wall upper surface 70a described above. The mounting portion 73 is provided radially outward from the resolver top plate portion 72 and is formed to be thicker than the resolver top plate portion 72. The mounting portion 73 is fixed to the upper end of the housing outer 13 by the bolt BT11. As described above, the mounting portion 73 is fixed to the outer wall of the chamber 101 by a fixing member such as a bolt.

[0101] The flange portion 74 is connected to the lower end of the inner wall portion 71 and extends radially inward. The flange portion 74 is provided so as to overlap the upper surface of the connecting portion 15 and is fixed to the connecting portion 15 by bolts BT10. The gap between the lower surface of the flange portion 74 and the upper surface of the connecting portion 15 is sealed by a sealing member SL4 such as an O-ring.

[0102] With this configuration, the resolver partition 70 can seal the space (vacuum atmosphere Va side) in which the resolver rotors 62A, 62B are arranged so that gas in the space (air atmosphere At side) in which the resolver stators 61A, 61B are arranged does not flow into the space (vacuum atmosphere Va side) in which the resolver rotors 62A, 62B are arranged. That is, the resolver stators 61A, 61B are provided in a space surrounded by the resolver partition 70, the housing outer 13, and the connecting portion 15. The resolver rotors 62A, 62B are provided in a space between the resolver partition 70 and the output shaft 17.

[0103] The outer peripheral surface 71a of the inner wall portion 71 is provided opposite to the outer peripheral surface of the protruding portion 17d of the output shaft 17 with a second gap G2 therebetween. In other words, the second gap G2 is a gap formed between the resolver partition wall 70 and the resolver rotors 62A, 62B in the radial direction. The second gap G2 is larger than the first gap G1 and larger than the third gap G3.

[0104] As a result, even if metal powder is generated due to wear of the first bearing 21A and the second bearing 21B, the metal powder is attracted to the connecting portion 15 when passing through the third gap G3 (where the magnetic field generated by the motor stator 30 acts), and it is possible to prevent the metal powder from flowing out to the resolver 60 side. In addition, since the second gap G2 is formed large, the rotating portion (the motor rotor 40, the resolver rotors 62A, 62B, the output shaft 17, the first bearing 21A, and the second bearing 21B) can be easily removed to the output shaft 17 side during maintenance, etc.

[0105] The shapes and configurations of the components of the motor 1 described above are merely examples and may be modified as appropriate. For example, the resolver partition 70 is not limited to being formed as a single unit, and may be divided into multiple parts. The fixing structure and sealing structure of each component may also be modified as appropriate.

[0106] As described above, the motor 1 of this embodiment includes the housing 10, the motor stator 30, the motor rotor 40, the bearings (the first bearing 21A and the second bearing 21B), the first seal structure LS1, the second seal structure LS2, and the resolver 60. The housing 10 includes the housing base 11 and the housing shaft portion 12 that is provided in the housing base 11 and extends in a direction along the rotation center axis AX. The motor stator 30 is disposed on the radial outside of the housing shaft portion 12. The motor rotor 40 is provided between the motor stator 30 and the housing shaft portion 12. The bearing is provided on the radial inside of the motor rotor 40 and rotatably supports the motor rotor 40 on the housing shaft portion 12. The first seal structure LS1 is provided on the output shaft 17 side of the motor rotor 40 and seals between the motor rotor 40 and the housing shaft portion 12. The second seal structure LS2 is provided on the housing base 11 side of the bearing in the axial direction of the motor rotor 40, and seals the gap between the motor rotor 40 and the housing base 11. The resolver 60 detects the rotation of the motor rotor 40. The resolver 60 is provided radially outward from the bearing and on the output shaft 17 side of the motor stator 30 in the direction along the rotation center axis AX. The bearing has an inner ring 22 provided on the housing shaft portion 12, an outer ring 23 provided on the motor rotor 40, and rolling elements 24 provided between the inner ring 22 and the outer ring 23, and a lubricant is enclosed between the inner ring 22 and the outer ring 23.

[0107] According to this, the bearing is provided on the radial inside of the motor rotor 40. A lubricant is sealed in the bearing, and the output shaft 17 side and the housing base 11 side of the bearing are sealed by the first seal structure LS1 and the second seal structure LS2, respectively. In addition, the output shaft 17 side of the motor rotor 40 is sealed by a lid or the like during use. Therefore, it is possible to suppress dust generated in the bearing from flowing out to the outside, for example, to the vacuum atmosphere Va side. In addition, even if dust (metal powder) generated by the wear of the bearing goes around inside the motor 1, the metal powder is attracted to the motor bulkhead 50 (by the magnetic force of the motor stator 30). Therefore, the motor 1 can suppress dust generated inside from flowing out to the outside. In addition, since the metal powder is suppressed from flowing out to the resolver 60 side, it is possible to suppress a decrease in the detection accuracy of the resolver 60.

[0108] In addition, the inner ring 22 and the outer ring 23 of the bearings in the motor 1 are made of magnetic stainless steel. With this, even if dust generated by the wear of the bearings gets inside the motor 1, the metal powder is effectively attracted to the permanent magnets of the motor stator 30 and the motor rotor 40.

[0109] Moreover, in the motor 1, the motor rotor 40 has a rotor yoke 41 and a plurality of magnets (magnets 42) provided along the outer periphery of the rotor yoke 41, the rotor yoke 41 is disposed radially inward of the plurality of magnets, and the bearings (first bearing 21A and second bearing 21B) are disposed radially inward of the rotor yoke 41. With this, even if metal powder generated due to wear of the bearing flows out of the seal structure (first seal structure LS1 and second seal structure LS2) and goes around into the inside of the motor, the metal powder is attracted to the magnets.

[0110] Furthermore, in the motor 1, the bearings (first bearing 21A and second bearing 21B) have a plurality of angular ball bearings arranged in a back-to-back configuration, which allows the bearings (first bearing 21A and second bearing 21B) to have improved rigidity against moment loads.

[0111] In the motor 1, at least one of the first seal structure LS1 and the second seal structure LS2 has a labyrinth structure formed with a gap of 0.05 mm or more and 0.15 mm or less, thereby enabling the motor 1 to satisfactorily seal between the motor rotor 40 and the housing shaft portion 12 in a non-contact manner.

[0112] In addition, in the motor 1, the bearing has a first bearing 21A and a second bearing 21B arranged along the axial direction, and has an inner ring spacer 25 provided between the inner ring 22 of the first bearing 21A and the inner ring 22 of the second bearing 21B, and an outer ring spacer 26 provided between the outer ring 23 of the first bearing 21A and the outer ring 23 of the second bearing 21B. With this, a fixed position preload is applied to the first bearing 21A and the second bearing 21B by the inner ring spacer 25 and the outer ring spacer 26, so that the rigidity can be improved compared to a fixed pressure preload. Also, since a lubricant is sealed in the bearing, the wear of the bearing is suppressed, so that a fixed position preload can be applied satisfactorily.

[0113] Moreover, the motor 1 has a motor partition 50 that is provided between the motor stator 30 and the motor rotor 40 and separates the space in which the motor stator 30 is disposed from the space in which the motor rotor 40 is disposed. With this, the motor partition 50 can prevent gas on the atmospheric side, where the motor stator 30 is disposed, from flowing out to the vacuum atmosphere side, where the motor rotor 40 is disposed.

[0114] In the motor 1, the resolver 60 includes resolver rotors 62A and 62B connected to the motor rotor 40, and resolver stators 61A and 61B provided radially outside the resolver rotors 62A and 62B and having excitation coils. A resolver partition 70 is provided between the resolver rotors 62A and 62B and the resolver stators 61A and 61B. This allows the resolver partition 70 to separate the space in which the resolver rotors 62A and 62B are arranged from the space in which the resolver stators 61A and 61B are arranged, and prevents the gas on the atmosphere side where the resolver stators 61A and 61B are arranged from flowing out to the vacuum atmosphere side where the resolver rotors 62A and 62B are arranged. In addition, the resolver 60 is used as an angle detector, and no electronic elements are provided in the motor 1. Therefore, even when the motor 1 is used in a high-temperature environment, the angle can be detected satisfactorily.

[0115] Furthermore, in the motor 1, the outer diameter of the motor rotor 40 is smaller than the outer diameters of the resolver rotors 62A, 62B. This allows the rotating structure including the motor rotor 40 and the resolver rotors 62A, 62B to be pulled out as a unit from the output shaft 17 side, facilitating replacement and maintenance of the bearings (first bearing 21A and second bearing 21B).

[0116] In addition, in the motor 1, a connecting portion 15 made of a magnetic material is disposed between the motor stator 30 and the resolver 60 in the direction along the central axis of rotation AX. This allows the connecting portion 15 to shield the magnetic field generated from the motor stator 30, thereby improving the detection accuracy of the resolver 60. The connecting portion 15 can also adsorb metal powder generated by wear.

[0117] Moreover, the motor 1 has an outer ring pressing portion (step portion 17b) provided on the output shaft 17 side of the motor rotor 40 and fixed to the outer ring 23 of the bearing, and an inner ring pressing portion 16 provided on the output shaft 17 side of the housing shaft portion 12 and fixed to the inner ring 22 of the bearing, and the seal structure LS has a labyrinth structure formed by the outer ring pressing portion and the inner ring pressing portion 16. With this, dust generated from the motor 1 due to wear of the bearing or the like is blocked by the seal structure LS, and it is possible to prevent the dust from leaking out to the outside.

[0118] Furthermore, in the motor 1, the motor stator 30 is disposed in a space closer to the atmosphere than the space in which the motor rotor 40 is disposed. This allows the cooling efficiency of the motor stator 30 to be improved compared to a case in which the motor stator 30 is disposed in the same space as the motor rotor 40, for example, in a vacuum atmosphere Va.

[0119] Furthermore, in the motor 1, the motor rotor 40 includes a samarium-cobalt permanent magnet. This prevents the magnet 42 from demagnetizing even when the motor 1 is used in a high-temperature environment, so that the motor rotor 40 can be rotated satisfactorily.

[0120] The motor 1 also includes a motor control circuit 90 that supplies a drive current Mi to the excitation coil 35 of the motor stator 30 based on the detection signal Sr of the resolver 60. This allows the motor control circuit 90 to constantly monitor the rotational torque and speed ripple based on the detection signal Sr of the resolver 60. This makes it possible to quickly find, for example, an abnormality in a bearing, or to know when to replace the bearing. [Explanation of symbols]

[0121] 1 Motor 10. Housing 11 Housing Base 12 Housing shaft 14 Cooling housing 14a Annular member 14b Projection 15 Connecting part 17 Output shaft 18 Cooling shaft 18a, 18b, 18c protrusion 21A No. 1 bearing 21B No. 2 bearing 22 Inner Circle 23 Outer Ring 24 Rolling elements 30 Motor stator 40 Motor rotor 41 Rotor yoke 50 Motor bulkhead 60 Resolver 61A, 61B Resolver stator 62A, 62B Resolver rotor 70 Resolver bulkhead 81 Refrigerant supply passage 82 First refrigerant flow path 82S First squeeze section 82T First pool 83 Second coolant flow path 83S Second squeeze section 83T Second pool 84 Refrigerant discharge passage 90 Motor control circuit 100 Semiconductor manufacturing equipment 101 Chamber 111 Transport table At atmospheric pressure Va Vacuum atmosphere LS1 1st seal structure LS2 Second seal structure

Claims

1. a housing including a housing base and a housing shaft portion provided on the housing base and extending in a direction along a central axis of rotation; a motor stator disposed radially outside the housing shaft portion; a motor rotor provided between the motor stator and the housing shaft portion; a bearing provided on a radially inner side of the motor rotor and configured to rotatably support the motor rotor on the housing shaft portion; a first seal structure provided on a side of the bearing opposite to the housing base in an axial direction of the motor rotor, the first seal structure sealingly sealing a gap between the motor rotor and the housing shaft portion; a second seal structure provided on the housing base side of the bearing in the axial direction of the motor rotor to seal between the motor rotor and the housing base; a resolver that detects rotation of the motor rotor, the resolver is provided radially outward of the bearing and on an opposite side of the motor stator to the housing base in a direction along the central axis of rotation, The bearing has an inner ring provided on the housing shaft portion, an outer ring provided on the motor rotor, and a rolling element provided between the inner ring and the outer ring, and a lubricant is sealed between the inner ring and the outer ring, a motor partition wall provided between the motor stator and the motor rotor to separate a space in which the motor stator is disposed from a space in which the motor rotor is disposed, the resolver includes a resolver rotor connected to the motor rotor, and a resolver stator provided radially outside the resolver rotor and including an excitation coil; a resolver partition is provided between the resolver rotor and the resolver stator; The outer diameter of the motor rotor is smaller than the outer diameter of the resolver rotor. Motor.

2. a housing including a housing base and a housing shaft portion provided on the housing base and extending in a direction along a central axis of rotation; a motor stator disposed radially outside the housing shaft portion; a motor rotor provided between the motor stator and the housing shaft portion; a bearing provided on a radially inner side of the motor rotor and configured to rotatably support the motor rotor on the housing shaft portion; a first seal structure provided on a side of the bearing opposite to the housing base in an axial direction of the motor rotor, the first seal structure sealingly sealing a gap between the motor rotor and the housing shaft portion; a second seal structure provided on the housing base side of the bearing in the axial direction of the motor rotor to seal between the motor rotor and the housing base; a resolver that detects rotation of the motor rotor, the resolver is provided radially outward of the bearing and on an opposite side of the motor stator to the housing base in a direction along the central axis of rotation, The bearing has an inner ring provided on the housing shaft portion, an outer ring provided on the motor rotor, and a rolling element provided between the inner ring and the outer ring, and a lubricant is sealed between the inner ring and the outer ring, A coupling portion made of a magnetic material is disposed between the motor stator and the resolver in a direction along the central axis of rotation. Motor.

3. a housing including a housing base and a housing shaft portion provided on the housing base and extending in a direction along a central axis of rotation; a motor stator disposed radially outside the housing shaft portion; a motor rotor provided between the motor stator and the housing shaft portion; a bearing provided on a radially inner side of the motor rotor and configured to rotatably support the motor rotor on the housing shaft portion; a first seal structure provided on a side of the bearing opposite to the housing base in an axial direction of the motor rotor, the first seal structure sealingly sealing a gap between the motor rotor and the housing shaft portion; a second seal structure provided on the housing base side of the bearing in the axial direction of the motor rotor to seal between the motor rotor and the housing base; a resolver that detects rotation of the motor rotor, the resolver is provided radially outward of the bearing and on an opposite side of the motor stator to the housing base in a direction along the central axis of rotation, The bearing has an inner ring provided on the housing shaft portion, an outer ring provided on the motor rotor, and a rolling element provided between the inner ring and the outer ring, and a lubricant is sealed between the inner ring and the outer ring, an outer ring pressing portion provided on the opposite side of the housing base in the axial direction of the motor rotor and fixed to an outer ring of the bearing; and an inner ring pressing portion provided on the opposite side of the housing base in the axial direction of the housing shaft portion and fixed to an inner ring of the bearing, The first seal structure has a labyrinth structure formed by the outer ring holding portion and the inner ring holding portion. Motor.

4. a motor partition wall provided between the motor stator and the motor rotor to separate a space in which the motor stator is disposed from a space in which the motor rotor is disposed; The motor according to claim 2 or 3.

5. the resolver includes a resolver rotor connected to the motor rotor, and a resolver stator provided radially outside the resolver rotor and including an excitation coil; A resolver partition is provided between the resolver rotor and the resolver stator.

5. The motor according to claim 4.

6. The outer diameter of the motor rotor is smaller than the outer diameter of the resolver rotor.

6. The motor according to claim 5.

7. The inner ring and the outer ring of the bearing are made of magnetic stainless steel. The motor according to any one of claims 1 to 6.

8. the motor rotor has a rotor yoke and a plurality of magnets provided along an outer periphery of the rotor yoke, the rotor yoke is disposed radially inside the plurality of magnets, The bearing is disposed radially inward of the rotor yoke. A motor according to any one of claims 1 to 7.

9. The bearing has a plurality of angular contact ball bearings arranged in a back-to-back configuration. A motor according to any one of claims 1 to 8.

10. At least one of the first seal structure and the second seal structure has a labyrinth structure formed with a gap of 0.05 mm or more and 0.15 mm or less. A motor according to any one of claims 1 to 9.

11. The bearing includes a first bearing and a second bearing arranged along the axial direction, an inner ring spacer provided between an inner ring of the first bearing and an inner ring of the second bearing; and an outer ring spacer provided between the outer ring of the first bearing and the outer ring of the second bearing. A motor according to any one of claims 1 to 10.

12. The motor stator is disposed in a space closer to the atmosphere than a space in which the motor rotor is disposed. A motor according to any one of claims 1 to 11.

13. The motor rotor includes a samarium cobalt permanent magnet. A motor according to any one of claims 1 to 12.

14. A motor control circuit is provided that supplies a drive current to an excitation coil of the motor stator based on a detection signal of the resolver. A motor according to any one of claims 1 to 13.

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