Rotation transmission device

Abstract

Provided is a rotation transmission device. The rotation transmission device comprises: a shaft body; a rotor; a housing; a stator that surrounds the housing around the axis; a bearing that is interposed between the inner circumferential surface of the housing and the outer circumferential surface of a support region located at a second end side in the shaft body with respect to the rotor, and that supports the shaft body so as to be rotatable about the axis relative to the housing; a magnetic fluid seal that blocks an internal space surrounded by the housing in a seal region located at the second end side in the shaft body with respect to the bearing; and a heat dissipating body that surrounds at least the outer side of the support region around the axis in the housing.

Description

Rotary transmission device Cross-reference to related applications

[0001] This international application claims priority based on Japanese Patent Application No. 2024-231915 filed with the Japan Patent Office on December 27, 2024, and incorporates the entire content thereof by reference into this international application.

[0002] This disclosure relates to a rotary transmission device that transmits rotation to a rotating object.

[0003] Conventionally, in a process such as manufacturing a semiconductor, processing is performed while rotating a rotating object in a reduced-pressure closed space. As such, as a device for transmitting rotation to a rotating object, a rotary transmission device has been proposed in which the end side of a shaft body rotated by a motor is sealed with a magnetic fluid and a rotating object is attached to the end face of this shaft body (see Patent Document 1).

[0004] Japanese Patent Application Laid-Open No. 2024-60469

[0005] However, in the process of manufacturing a semiconductor, the closed space or the rotating object may be placed in a high-temperature environment. In this case, heat flowing in via the rotating object may be transmitted to the motor through the shaft body. As a result, there is a problem that the operation of the motor becomes unstable due to the influence of this heat.

[0006] One aspect of this disclosure is to provide a technique for suppressing the influence of heat on a motor in a rotary transmission device.

[0007] To solve the above problems, the first phase of the rotational transmission device comprises a shaft extending in a predetermined direction, a rotor provided so as to surround the shaft around its axis and which is driven by the rotation of the shaft around its axis, a housing which is a cylindrical member surrounding the shaft around its axis outside the rotor, with a first end of this member being closed and a second end being open, a stator which surrounds the housing around its axis and is provided so as to face the rotor in the inward and outward directions and is fixed to the housing, and a part of the shaft that is further from the rotor The device comprises: a bearing interposed between the outer circumferential surface of a support region at two ends and the inner circumferential surface of the housing, supporting the shaft so that it can rotate around its axis relative to the housing; a magnetic fluid seal that seals the internal space surrounded by the housing in the seal region by interposing magnetic fluid between the outer circumferential surface of a seal region on the second end side of the shaft and the inner circumferential surface of the housing; and a heat sink that surrounds at least the outside of the support region around its axis in the housing, promoting heat dissipation from the outer circumferential surface of the housing.

[0008] In this rotational transmission device, heat dissipation is promoted from the support area through the bearings, housing, and heat sink. As a result, heat is less likely to be transferred to the motor (rotor and stator) in the adjacent area, thus suppressing the thermal impact on the motor.

[0009] This phase may also be as shown in the second phase below. In the second phase, the thermal resistance per unit thickness along the axial direction in the adjacent region adjacent to the support region at the first end of the shaft is greater than that of the support region.

[0010] In this type of rotational transmission device, the difference in thermal resistance suppresses heat conduction from the support region of the shaft to adjacent regions. As a result, heat is less likely to reach the motor (rotor and stator) located closer to the adjacent region, thus reducing the thermal impact on the motor.

[0011] This phase may also be as shown in the third and fourth phases below. In the third phase, the shaft has a hole that extends from the first end to the adjacent region, and the cross-sectional area intersecting the axis in the adjacent region is smaller than that of the support region.

[0012] In this type of rotational transmission device, the hole extending from the first end to the adjacent region makes the cross-sectional area of ​​the adjacent region smaller than that of the support region, thereby increasing the thermal resistance of the adjacent region compared to that of the support region.

[0013] In the fourth phase, the shaft may be formed of a material with a lower thermal conductivity than the support region in at least a portion of the adjacent region.

[0014] In this type of rotational transmission device, the thermal resistance in the adjacent region can be made greater than that of the support region by forming a portion of the adjacent region with a material that has a lower thermal conductivity than the support region.

[0015] This phase may be as shown in the fifth and sixth phases below. In the fourth phase, the shaft is formed of a material with lower thermal conductivity than the support region in a region extending a predetermined thickness in at least the adjacent region.

[0016] In this type of rotational transmission device, the thermal resistance in the adjacent region can be made greater than that of the support region by forming a region of a predetermined thickness in the adjacent region with a material that has a lower thermal conductivity than the support region.

[0017] In the sixth phase, the shaft body may be formed of a material in which the entire adjacent region has a lower thermal conductivity than the support region.

[0018] In this type of rotational transmission device, the thermal resistance in the adjacent region can be made greater than that of the support region because the entire adjacent region is made of a material with lower thermal conductivity than the support region.

[0019] Furthermore, each of the above phases may be as shown in the seventh phase below. In the seventh phase, an inner fitting groove is formed in the support region around the entire circumference of the axis, and the inner ring of the bearing of the shaft is fitted into this inner fitting groove.

[0020] In this type of rotational transmission device, the internal fitting groove formed in the support region increases the contact area between the bearing and the support region, i.e., the shaft, not only on its inner circumferential surface but also on the first and second end faces of the bearing's inner ring. Therefore, heat dissipation from the support region through the bearing, housing, and heat sink can be effectively promoted.

[0021] Furthermore, each of the above phases may be as shown in the eighth phase below. In the eighth phase, an outer fitting groove is formed around the entire circumference of the axis in the region of the inner circumferential surface of the housing that faces the support region and the inner and outer sides, and the bearing outer ring of the bearing is fitted into this outer fitting groove.

[0022] In this type of rotational transmission device, the external fitting groove formed in the housing allows the bearing to engage not only with its outer surface but also with the first and second end faces of the bearing's outer ring, thereby increasing the contact area. As a result, heat dissipation from the support area through the bearing, housing, and heat sink can be effectively promoted.

[0023] Front view of a rotary transmission device and vacuum chamber according to one embodiment of the present disclosure Cross-sectional view of a rotary transmission device and vacuum chamber according to one embodiment of the present disclosure, taken along the plane formed by the axial direction and its intersecting direction (view taken along the line A-A in Figure 1) Cross-sectional view of a rotary transmission device according to one embodiment of the present disclosure, taken along the plane formed by the axial direction and its intersecting direction (view taken along the line A-A in Figure 1) Cross-sectional view of each of the components of a rotary transmission device according to one embodiment of the present disclosure, taken along the plane formed by the axial direction and its intersecting direction (view taken along the line A-A in Figure 1) Magnetic flow in a rotary transmission device according to one embodiment of the present disclosure Cross-sectional view of the main part of the body seal, viewed in cross-section along the plane formed by the axial direction and its intersecting direction. Cross-sectional view of each of the components of the rotary transmission device in another embodiment, viewed in cross-section along the plane formed by the axial direction and its intersecting direction (view taken along the line A-A in Figure 1) (1 / 3) Cross-sectional view of each of the components of the rotary transmission device in another embodiment, viewed in cross-section along the plane formed by the axial direction and its intersecting direction (view taken along the line A-A in Figure 1) (2 / 3) Cross-sectional view of each of the components of the rotary transmission device in another embodiment, viewed in cross-section along the plane formed by the axial direction and its intersecting direction (view taken along the line A-A in Figure 1) (3 / 3)

[0024] Embodiments of the present disclosure will be described below with reference to the drawings. (1) Overall configuration (1-1) The first embodiment of the rotation transmission device 1 is a device attached to a processing apparatus that processes an object to be rotated in a depressurized closed space in order to rotate the object to be rotated. In this embodiment, as shown in Figures 1 and 2, the rotation transmission device 1 is attached to a vacuum chamber 3 of a semiconductor manufacturing apparatus that processes an object to be rotated in a depressurized closed space in order to rotate the turntable 2.

[0025] As shown in Figure 3, the rotation transmission device 1 comprises a shaft 10 extending in a predetermined direction (up and down in the figure), a rotor 20 surrounding the shaft 10 around an axis 110 extending in the predetermined direction, a cylindrical housing 30 surrounding the shaft 10 outside the rotor 20 around the axis 110, a stator 40 surrounding the housing 30 around the axis 110, a bearing 50 supporting the shaft 10 so that it can rotate around the axis 110 relative to the housing 30, a magnetic fluid seal 60 sealing the internal space surrounded by the housing 30, a heat sink 70 surrounding the outside of the housing 30 around the axis 110, and a rotation detection unit 80 for detecting the rotation of the shaft 10.

[0026] As shown in Figure 3, the shaft 10 has a first end 10a (lower end in the figure) and a second end 10b (upper end in the figure). The first end 10a is one end of the shaft 10 that lies along the axis 110, and the second end 10b is the end of the shaft 10 opposite to the first end 10a. The shaft 10 has a mounting surface 11 formed on the second end 10b side for attaching the object to be rotated, with the first end 10a side being housed in the housing 30. In this embodiment, the object to be rotated is screwed to the shaft 10 while positioned along the mounting surface 11 of the shaft 10.

[0027] Furthermore, the shaft body 10 is provided with a flange 13 that widens to a larger diameter at the second end 10b than in the rest of the shaft. This flange 13 is positioned on the first end 10a side of the bearing 50.

[0028] Furthermore, as shown in Figure 4, the shaft body 10 has a support region 15 located on the second end 10b side of the rotor 20, and an adjacent region 17 adjacent to the support region 15 on the first end 10a side. In this case, the entire area of ​​the shaft body 10 on the first end 10a side of the support region 15 is the adjacent region 17.

[0029] The shaft 10 is configured such that the thermal resistance per unit thickness along the axis 110 in the adjacent region 17 is greater than the thermal resistance of the support region 15.

[0030] In this embodiment, the shaft 10 has a hole 120 that extends from the first end 10a to the adjacent region 17. This hole 120 makes the cross-sectional area where it intersects the axis 110 in the adjacent region 17 smaller than that of the support region 15, thereby making the thermal resistance in the adjacent region 17 greater than that of the support region 15. In this embodiment, the hole 120 extends from the first end 10a of the shaft 10 to the boundary between the support region 15 and the adjacent region 17.

[0031] The rotor 20 is provided so as to surround the shaft body 10 around the axis 110 and is driven by the rotation of the shaft body 10 around the axis 110. In this embodiment, the rotor 20 is provided along the outer circumference of the shaft body 10 at a position on the first end 10a side of the flange 13 along the axis 110.

[0032] The housing 30 is a cylindrical member that surrounds the shaft 10 around the axis 110, outside the rotor 20. The lower end (first end 10a) of this member is closed, while the upper end (second end 10b) is open. The housing 30 is made of a non-magnetic material.

[0033] The stator 40 surrounds the housing 30 around the axis 110 and is positioned to face the rotor 20 in the inward and outward directions, and is fixed to the housing 30. In this embodiment, the stator 40 surrounds the shaft 10 on the outside of the housing 30 and is fixed to the outer circumferential surface of the housing 30 in a state where it faces the rotor 20 in the inward and outward directions across a partition wall in the housing 30.

[0034] The bearing 50 is interposed between the outer circumferential surface of the support region 15 on the shaft 10 and the inner circumferential surface of the housing 30, and supports the shaft 10 so that it can rotate around the axis 110 relative to the housing 30. In this embodiment, a ball bearing is used as the bearing 50.

[0035] Here, an inner fitting groove 15a is formed in the support region 15 of the shaft body 10, extending around the entire circumference of the axis 110, and the inner bearing ring 51 of the bearing 50 is fitted into this inner fitting groove 15a. In addition, an outer fitting groove 31 is formed in the inner circumferential surface of the housing 30, extending around the entire circumference of the axis 110 in the region facing the support region 15, and the outer bearing ring 53 of the bearing 50 is fitted into this outer fitting groove 31.

[0036] The magnetic fluid seal 60 seals the internal space surrounded by the housing 30 with the seal region 19 by interposing magnetic fluid 63 between the outer circumferential surface of the seal region 19 located on the second end 10b side of the bearing 50 on the shaft body 10 and the inner circumferential surface of the housing 30.

[0037] As shown in Figure 5, the magnetic fluid seal 60 comprises a pair of magnetic poles 61 that protrude from the shaft 10 toward the housing 30 in the sealing region 19, and a magnetic fluid 63 interposed between the tip of the magnetic poles 61 and the housing 30. The magnetic poles 61 may be provided to protrude from the housing 30 toward the shaft 10 in the sealing region 19, in which case the magnetic fluid 63 may be interposed between the tip of the magnetic poles 61 and the shaft 10.

[0038] Each of these magnetic poles 61 has a permanent magnet 65 sandwiched at its tip. The pair of magnetic poles 61 magnetically holds the magnetic fluid 63 between the shaft 10 and the housing 30 by forming a magnetic circuit (see dashed line in the figure) located between the tips of the pair of magnetic poles 61 and the housing 30.

[0039] The heat sink 70 is a block that surrounds at least the outside of the support area 15 of the housing 30 around the axis 110, and is intended to promote heat dissipation from the outer surface of the housing 30. The heat sink 70 is equipped with a coolant inlet 71 and outlet 73 provided on the side, as well as a flow path 75 connecting them. The flow path 75 is arranged to circulate around the axis 110 within the housing 30 and the stator 40.

[0040] The rotation detection unit 80 is a magnetic encoder disposed on the first end 10a side of the shaft body 10 relative to the rotor 20, and includes a magnet piece 81 that rotates around the axis 110 following the shaft body 10, and a magnetic sensor 83 that detects a change in the magnetic field accompanying the rotation of the magnet piece 81 as the rotation of the shaft body 10.

[0041] Among these, the magnet piece 81 has a plurality of opposing magnetic poles (S poles, N poles) alternately adjacent to each other around the axis 110. The magnetic sensor 83 is a Hall element that detects a change in the magnetic poles along the axis 110.

[0042] In the rotation transmission device 1 configured as described above, with a rotation object attached to the second end 10b side of the shaft body 10, the shaft body 10 is rotated together with the rotor 20 by energizing the stator 40, and this rotation is transmitted to the rotation object. (1-2) Second Embodiment The rotation transmission device 1 of this embodiment is different from the first embodiment in that at least a part of the adjacent region 17 of the shaft body 10 is formed of a material having a lower thermal conductivity than the support region 15.

[0043] As such a rotation transmission device 1, for example, it is conceivable to form a region having a predetermined thickness in the adjacent region 17 of a material having a lower thermal conductivity than the support region 15. Specifically, as shown in FIG. 6, the surface on the second end 10b side of the adjacent region 17 may be constituted by a sheet member 17a of a material (for example, a resin material) having a lower thermal conductivity than the support region 15. Here, other than the sheet member 17a in the adjacent region 17 may be constituted of a metal material or the like having a higher thermal conductivity than the sheet member 17a. Each region may be screwed in the direction of the axis 110.

[0044] Also, as the rotation transmission device 1 of this embodiment, it is conceivable to form the entire adjacent region 17 of a material having a lower thermal conductivity than the support region 15. Specifically, as shown in FIG. 7, the entire adjacent region 17 may be constituted of a material (for example, a resin material) having a lower thermal conductivity than the support region 15. Here, the support region 15 may be constituted of a metal material or the like having a higher thermal conductivity than the adjacent region 17. Each region may be screwed in the direction of the axis 110.

[0045] Further, as the rotation transmission device 1 of the present embodiment, it is conceivable to provide a portion made of a material having a low thermal conductivity in a part of the adjacent region 17. Specifically, as shown in FIG. 8, a cylindrical gap 130 extending in the direction of the axis 110 is provided in the adjacent region 17, and a material having a lower thermal conductivity than other regions (for example, a resin material) may be filled therein to form a filling portion 131. Here, the support region 15 and the adjacent region 17 may be made of a metal material or the like having a higher thermal conductivity than the adjacent region 17. (2) Modified Example As described above, the embodiments of the present disclosure have been described. However, the present disclosure is not limited to the above embodiments, and it is needless to say that the present disclosure can take various forms as long as it belongs to the technical scope of the present disclosure.

[0046] For example, in the above embodiment, the configuration in which the hole 120 extending from the first end 10a of the shaft body 10 to the adjacent region 17 is formed is illustrated. However, this hole 120 only needs to have a smaller cross-sectional area in the adjacent region 17 than in the support region 15, and does not necessarily have to be a hole extending from the first end 10a of the shaft body 10.

[0047] Further, in the above embodiment, the configuration in which the rotor 20 is provided on the outer periphery of the shaft body 10 and integrated with the shaft body 10 so that the rotor 2 is driven by the rotation of the shaft body 10 around the axis 110 is illustrated. However, the rotor 20 only needs to be configured so that the rotor 20 is driven by the rotation of the shaft body 10 around the axis 110, and does not necessarily have to be integrated with the shaft body 10. Specifically, it is conceivable to form a hole such as the gap 130 in the second embodiment.

[0048] Further, in the above embodiment, the configuration in which the stator 40 surrounds the shaft body 10 outside the housing 30 and is fixed to the outer peripheral surface of the housing 30 is illustrated. However, the stator 40 may surround the shaft body 10 inside the housing 30 and be fixed to the inner peripheral surface of the housing 30.

[0049] Further, in the above embodiment, the configuration in which the magnetic pole 61 in the magnetic fluid seal 60 is provided on the shaft body 10 side is illustrated. However, this magnetic pole 61 may be provided on the housing 30 side.

[0050] Furthermore, in the above embodiment, a configuration in which a magnetic encoder is used as the rotation detection unit 80 is illustrated. However, a configuration in which an optical or electromagnetic induction encoder is used as the rotation detection unit 80 is also possible. (3) Operation and Effects In the rotation transmission device 1 of the above embodiment, heat dissipation is promoted from the support region 15 through the bearing 50, housing 30 and heat sink 70. In addition, in the rotation transmission device 1 of the above embodiment, the conduction of heat from the support region 15 of the shaft body 10 to the adjacent region 17 is suppressed due to the difference in thermal resistance.

[0051] For example, in a configuration in which a hole 120 is formed extending from the first end 10a to the adjacent region 17, the thermal resistance in the adjacent region 17 can be made greater than that of the support region 15 by making the cross-sectional area of ​​the adjacent region 17 smaller than that of the support region 15. Also, in a configuration in which part or all of the adjacent region 17 is formed of a material with lower thermal conductivity than that of the support region 15, the presence of this material can make the thermal resistance in the adjacent region 17 greater than that of the support region 15.

[0052] In this way, the rotational transmission device 1 makes it difficult for heat to be transferred to the motor (rotor 20 and stator 40) located in the adjacent region 17, thereby suppressing the thermal effects on the motor.

[0053] Furthermore, in the above embodiment of the rotational transmission device 1, the inner fitting groove 15a formed in the support region 15 allows the bearing 50 to engage not only with its inner circumferential surface, but also with the first end 10a side and the second end 10b side of the bearing inner ring 51, thereby increasing the contact area with the support region 15, i.e., the shaft 10. As a result, heat dissipation from the support region 15 through the bearing 50, housing 30, and heat sink 70 can be effectively promoted.

[0054] Furthermore, in the above embodiment of the rotational transmission device 1, the outer fitting groove 31 formed in the housing 30 allows the bearing 50 to fit not only its outer surface but also the first end 10a side and the second end 10b side of the bearing outer ring 53 with the housing 30, thereby increasing the contact area. As a result, heat dissipation from the support area 15 through the bearing 50, housing 30, and heat sink 70 can be effectively promoted.

[0055] 1...Rotation transmission device, 2...Turntable, 3...Vacuum chamber, 10...Shaft body, 10a...First end, 10b...Second end, 11...Mounting surface, 13...Flange, 15...Support area, 15a...Inner fitting groove, 17...Adjacent area, 17a...Sheet member, 19...Seal area, 20...Rotor, 30...Housing, 31...Outer fitting groove, 40...Stator, 50...Bearing, 51...Inner ring of bearing, 53...Outer ring of bearing, 60...Magnetic fluid seal, 61...Magnetic pole, 63...Magnetic fluid, 65...Permanent magnet, 70...Heat sink, 71...Inlet, 73...Outlet, 75...Flow path, 80...Rotation detection unit, 81...Magnet piece, 83...Magnetic sensor, 110...Axis, 120...Hole, 130...Gap, 131...Filling part.

Claims

1. A shaft extending in a predetermined direction; a rotor provided to surround the shaft around its axis and to follow the rotation of the shaft around its axis; a housing which is a cylindrical member surrounding the shaft around its axis outside the rotor, with a first end of the member being closed and a second end being open; a stator which surrounds the housing around its axis and is provided so as to face the rotor in the inward and outward directions and is fixed to the housing; a bearing interposed between the outer circumferential surface of a support region on the shaft located on the second end side of the rotor and the inner circumferential surface of the housing, supporting the shaft so that the shaft can rotate around its axis relative to the housing; a magnetic fluid seal which seals the internal space surrounded by the housing in the seal region by interposing magnetic fluid between the outer circumferential surface of a seal region on the shaft located on the second end side of the bearing and the inner circumferential surface of the housing; A rotational transmission device comprising a heat sink that surrounds at least the outside of the support area around the axis within the housing and promotes heat dissipation from the outer surface of the housing.

2. The rotational transmission device according to claim 1, wherein the shaft has a thermal resistance per unit thickness along the axial direction in an adjacent region adjacent to the support region at the first end side, which is greater than that of the support region.

3. The rotational transmission device according to claim 2, wherein the shaft has a hole formed therein that extends from the first end to the adjacent region, and the cross-sectional area intersecting the axis in the adjacent region is smaller than that of the support region.

4. The rotational transmission device according to claim 2 or 3, wherein at least a portion of the adjacent region of the shaft is made of a material with lower thermal conductivity than the support region.

5. The rotational transmission device according to claim 4, wherein the shaft body is formed of a material with lower thermal conductivity than the support region in a region extending a predetermined thickness in at least the adjacent region.

6. The rotational transmission device according to claim 4, wherein the shaft body is formed in an adjacent region of a material with a lower thermal conductivity than the support region.

7. The rotational transmission device according to any one of claims 2 to 6, wherein an inner fitting groove is formed in the support region around the entire circumference of the axis, and the inner ring of the bearing of the shaft is fitted into this inner fitting groove.

8. The rotational transmission device according to claim 7, wherein an outer fitting groove is formed around the entire circumference of the axis in the region of the inner circumferential surface of the housing that faces the support region and the inner and outer regions, and the bearing outer ring of the bearing is fitted into this outer fitting groove.

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