Actuator

Abstract

An actuator 1 includes a motor 20 and a speed reducer 30 that are mutually connected. A heat transfer member 25 that is elastic is disposed between: a coil end 232a of the motor 20; and a first speed-reducer casing 34A of the speed reducer 30.

Description

Actuator

[0001] The present invention relates to an actuator.

[0002] Conventionally, actuators equipped with a motor and a reducer have been known (see, for example, Patent Document 1). Heat generation by the motor is a problem with this type of actuator. For a motor alone, a common method is to dissipate heat from the casing (housing) by providing heat dissipation fins on the casing, but there is still room for improvement in the cooling performance (heat dissipation).

[0003] Japanese Patent Application Laid-Open No. 2021-97430

[0004] The present invention has been made in view of the above circumstances, and has an object to improve the heat dissipation performance of a motor.

[0005] The present invention provides an actuator comprising a motor and a reducer connected to each other, and an elastic heat transfer member disposed between the coil end of the motor and a reducer casing of the reducer.

[0006] According to the present invention, the heat dissipation performance of the motor can be improved.

[0007] Fig. 2 is a cross-sectional view showing an actuator according to a first embodiment; Fig. 3 is an enlarged view of the periphery of a motor in Fig. 1; Fig. 4 is a cross-sectional view showing an actuator according to a second embodiment;

[0008] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0009] First Embodiment FIG. 1 is a cross-sectional view showing an actuator 1 according to a first embodiment of the present invention, and FIG. 2 is an enlarged view of the motor 20 and its surroundings. As shown in FIG. 1 , the actuator 1 according to the first embodiment includes a motor 20, a reducer 30, a brake 40, and a circuit unit 50. The application of the actuator 1 is not particularly limited, and it may be incorporated into a joint of an industrial robot, a collaborative robot, or a service robot, for example. In the following description, the direction along the central axis Ax of the actuator 1 is referred to as the "axial direction," the direction perpendicular to the central axis Ax is referred to as the "radial direction," and the direction of rotation about the central axis Ax is referred to as the "circumferential direction." In addition, in the axial direction, the side coupled to a driven member (not shown) (the left side in the drawing) is referred to as the "output side (load side)," and the side opposite the output side (the right side in the drawing) is referred to as the "anti-output side (anti-load side)."

[0010] [Motor Configuration] The motor 20 includes a rotating shaft 21, a motor rotor 22, a motor stator 23, and a motor casing 24. The rotating shaft 21 is disposed so as to pass through the center from the reducer 30 to the brake 40, and is supported rotatably about a central axis Ax. The motor rotor 22 is fixed to the outer peripheral surface of the rotating shaft 21 and rotates integrally with the rotating shaft 21. The motor rotor 22 has a permanent magnet, such as a neodymium magnet, on its outer peripheral surface.

[0011] The motor stator 23 is configured by winding a coil around a stator core 231 made of, for example, laminated steel plates. The motor stator 23 is arranged concentrically on the outer periphery of the motor rotor 22. Coil ends 232, which are exposed portions of the coil wound around the stator core 231, protrude from both axial sides of the motor stator 23. The entire coil end 232 is molded with resin. Elastic heat transfer members 25 are sandwiched between the output-side coil end 232a and the first reducer casing 34A of the reducer 30, and between the counter-output-side coil end 232b and the cover member 61. Details of the contact state of the heat transfer members 25 will be described later.

[0012] The motor casing 24 covers the outer periphery of the motor rotor 22 and the motor stator 23, and the motor stator 23 is fitted into the inner periphery. The motor casing 24 is made of aluminum, although not particularly limited thereto, primarily for the purposes of reducing weight and improving cooling performance. The type of motor 20 is not particularly limited, and may be, for example, an induction motor instead of a permanent magnet type.

[0013] [Configuration of the Reducer] The reducer 30 is a center-crank eccentric oscillating reducer and is disposed on the output side of the motor 20. Specifically, the reducer 30 includes multiple (two) eccentric bodies 31a, 31b, external gears 32A, 32B, first to third output shafts 33A, 33B, a first reducer casing 34A, and a second reducer casing 34B. The eccentric bodies 31a, 31b are provided on the outer peripheral surface of the rotating shaft 21. In this embodiment, the rotating shaft 21 serves as both the output shaft of the motor and the input shaft of the reducer, but the output shaft of the motor and the input shaft of the reducer may be separate bodies and connected to each other.

[0014] The external gears 32A, 32B have a plurality of inner pin holes provided circumferentially spaced apart at positions offset from the central axis Ax, and a central through-hole through which the rotating shaft 21 is inserted. The external gears 32A, 32B are rotatably supported with respect to the eccentric bodies 31 a, 31 b by eccentric body bearings 35 a, 35 b disposed between the external gears 32A, 32B and the eccentric bodies 31 a, 31 b, respectively, and oscillate with the rotation of the eccentric bodies 31 a, 31 b.

[0015] The first output shaft 33A is disposed on the outer periphery of the rotary shaft 21 and on the output side of the external gears 32A and 32B. The second output shaft 33B is disposed on the output side of the first output shaft 33A, and the third output shaft 33C is disposed on the output side of the second output shaft 33B. The first to third output shafts 33A to 33C are fixed to each other and to a driven member (not shown) (e.g., a distal arm member of a robot). The first output shaft 33A rotatably supports the rotary shaft 21 via a bearing 36 disposed between the first output shaft 33A and the rotary shaft 21. The first output shaft 33A has multiple inner pins 33p formed to bulge outward in a pin-like shape toward the opposite output side. The inner pins 33p are inserted into the inner pin holes of the external gears 32A and 32B. A retaining plate 38 is disposed on the opposite output side of the inner pins 33p to restrict movement of the external gear 32A toward the opposite output side. In addition, an inner roller is rotatably fitted onto the inner pin 33p to promote sliding with the inner pin hole of the external gear 32, and the retaining plate 38 also restricts movement of the inner roller toward the anti-output side.

[0016] As shown in FIG. 2 , the retaining plate 38 has a disk portion 38a disposed perpendicular to the axial direction, a cylindrical portion 38b extending from the inner peripheral end of the disk portion 38a toward the non-output side, and an extension portion 38c extending from the non-output side end of the cylindrical portion 38b toward the inner peripheral side. The outer peripheral portion of the disk portion 38a is held (or fitted) in the first reducer casing 34A, and the non-output side surface is substantially flush with the surface of the first reducer casing 34A. The cylindrical portion 38b has a tapered shape that gradually decreases in diameter from the output side toward the non-output side. The outer diameter of the extension portion 38c is larger than the outer diameter of the restricting member 39a and smaller than the outer diameter of the restricting member 39a. The restricting member 39a is fitted to the outer peripheral surface of the rotating shaft 21 at the non-output side of the eccentric body bearing 35a to restrict movement of the eccentric body bearing 35a toward the non-output side. A first retaining ring 39b fitted into a circumferential groove in the rotating shaft 21 is disposed on the side of the restricting member 39a opposite the output side. A second retaining ring 39c fitted into a circumferential groove in the rotating shaft 21 is disposed on the axially opposite side of the extending portion 38c from the first retaining ring 39b. A labyrinth seal is formed by the cylindrical portion 38b and extending portion 38c of the retaining plate 38, the restricting member 39a, the first retaining ring 39b, the second retaining ring 39c, and the rotating shaft 21. This allows for a compact and low-loss configuration, compared to providing an oil seal in this portion, to provide an appropriate seal between the motor 20 and the reducer 30, and to prevent the outflow of lubricant from the reducer 30.

[0017] As shown in FIG. 1 , the first reducer casing 34A is disposed on the outer periphery of the external gears 32A, 32B and the retaining plate 38. An internal gear 34g is provided on the inner periphery of the first reducer casing 34A. The internal gear 34g has a plurality of external pins that form internal teeth and internally meshes with the external gears 32A, 32B. The second reducer casing 34B is disposed on the outer periphery of the first output shaft 33A and the second output shaft 33B. The second reducer casing 34B rotatably supports the first output shaft 33A via a main bearing 37 disposed between the second reducer casing 34B and the first output shaft 33A. The second reducer casing 34B is fixed to the first reducer casing 34A. The second reducer casing 34B is also fixed to a mating member E (e.g., a base-end arm member of a robot).

[0018] With this configuration, in the reducer 30, the eccentric bodies 31a and 31b rotate inside the external gears 32A and 32B in response to the rotation of the rotating shaft 21 output from the motor 20, causing the external gears 32A and 32B to oscillate in different phases from each other. The oscillation of the external gears 32A and 32B causes the external teeth farthest from the central axis Ax to mesh with the internal gear 34g, and this meshing position changes circumferentially as the oscillation occurs. Specifically, with each rotation of the rotating shaft 21, the meshing position between the internal gear 34g and the external gears 32A and 32B moves around the circumference. There is a difference in the number of teeth between the external gears 32A and 32B and the internal gear 34g, and each time the meshing position with the internal gear 34g moves around the circumference, the external gears 32A and 32B rotate by the difference in the number of teeth. This rotation is transmitted to the first to third output shafts 33A to 33C via the inner pin 33p, whereby the rotational motion of the rotary shaft 21 is decelerated and extracted from the driven member connected to the third output shaft 33C.

[0019] [Structure of the Brake] The brake 40 is disposed on the opposite side to the output side of the motor 20. The brake 40 in this embodiment is a holding brake that holds the rotating shaft 21 in a stopped state, although this is not particularly limited.

[0020] The brake 40 includes a hub member 41, a rotor 42, an armature 43, an electromagnetic coil 44, a plate 46, a frame 47, and a brake casing 48. The hub member 41 is fixed (connected by a key, for example) to the rotating shaft 21 that extends from the motor 20 to the inside of the brake 40, and the rotor 42 is formed in a disk shape and connected to the hub member 41 by a spline or the like. Therefore, the rotor 42 rotates integrally with the rotating shaft 21.

[0021] The armature 43 is disposed on the output side of the rotor 42 and is supported so as to be displaceable in the axial direction so as to move toward and away from the rotor 42. Meanwhile, a plate 46 is disposed on the anti-output side of the rotor 42 and is supported by a frame 47. Two friction materials (linings) 43a, 46a are fixed to the respective surfaces of the armature 43 and plate 46 that face the rotor 42 in the axial direction. Of these, the one provided on the armature 43 is the movable friction material 43a, and the one provided on the plate 46 is the fixed friction material 46a.

[0022] The electromagnetic coil 44 moves the armature 43 in the axial direction by a magnetic force generated when current is passed through it, and moves the movable friction material 43a toward and away from the rotor 42. The frame 47 is supported by a brake casing 48 and holds the electromagnetic coil 44, the plate 46, etc. The brake casing 48 is fixed to a cover member 61.

[0023] A cover member 61 is disposed between the brake 40 and the motor 20. A bearing 62 that rotatably supports the rotating shaft 21 and an oil seal 63 that seals between the motor 20 and the brake 40 are disposed on the inner periphery of the cover member 61. The cover member 61 is fastened together with the brake casing 48, the motor casing 24, and the first reducer casing 34A by fastening screws 64.

[0024] In the brake 40 having the above configuration, the action of the electromagnetic coil 44 pinches the rotor 42 between the armature 43 and the plate 46 via the respective friction materials 43a, 46a, thereby applying a braking force (holding force) to the rotating shaft 21. Conversely, the action of the electromagnetic coil 44 releases the force that pinches the rotor 42 between the armature 43 and the plate 46, thereby releasing the braking force (holding force) on the rotating shaft 21. Note that the brake 40 of this embodiment is a non-excitation actuated brake, and when the electromagnetic coil 44 is not energized, it is actuated by the biasing force of a spring (not shown), and the armature 43 presses the rotor 42 to hold the rotating shaft 21 in a stopped state.

[0025] [Configuration of Circuit Unit] The circuit unit 50 is disposed on the opposite output side of the brake 40. The circuit unit 50 includes a rotation detection unit 51 that detects the rotation of the rotary shaft 21, a motor driver board on which a drive circuit for the motor 20 is mounted, an encoder board on which a detection circuit for the rotation detection unit 51 is mounted, and the like. These components are housed in a circuit unit casing 52 that is fixed to the brake casing 48.

[0026] 2 , an elastic heat transfer member 25 is interposed between each coil end 232 of the motor 20 and an adjacent member on the axial outside thereof. Specifically, a first heat transfer member 25a is disposed between the output-side coil end 232a and the first reducer casing 34A of the reducer 30, and a second heat transfer member 25b is disposed between the anti-output-side coil end 232b and the cover member 61. More specifically, because each coil end 232 is resin-molded, each heat transfer member 25 is disposed (sandwiched) between the resin-molded coil end 232 (i.e., the mold resin that molds the coil end 232) and the first reducer casing 34A or the cover member 61. Furthermore, each heat transfer member 25 is sandwiched between the coil end 232 and the first reducer casing 34A or the cover member 61 in a more compressed state (a state in which the axial dimension is smaller) than before assembly (before being assembled between the coil end 232 and the first reducer casing 34A or the cover member 61). In other words, the axial dimension between the coil end 232 and the first reducer casing 34A or the cover member 61 is smaller (shorter) than the axial dimension of the heat transfer member 25 before assembly.

[0027] The first heat transfer member 25a on the output side contacts the first reducer casing 34A of the reducer 30 and also contacts the retaining plate 38 on the inner circumferential side thereof. However, it is preferable that the axial compression (force) of the first heat transfer member 25a between the coil end 232a and the retaining plate 38 is weaker than the axial compression (force) of the first heat transfer member 25a between the coil end 232a and the first reducer casing 34A. In other words, with respect to the space in which the first heat transfer member 25a is installed, it is preferable that the axial dimension between the coil end 232a and the retaining plate 38 is larger (longer) than the axial dimension between the coil end 232a and the first reducer casing 34A. It is also preferable that the first heat transfer member 25a on the output side have higher heat conductivity than the second heat transfer member 25b on the opposite side to the output side. To achieve this, the first heat transfer member 25a may have a higher thermal conductivity than the second heat transfer member 25b, or the axial compression of the first heat transfer member 25a may be stronger than that of the second heat transfer member 25b.

[0028] The heat transfer member 25 is not particularly limited as long as it is elastic and has a thermal conductivity greater than that of air (approximately 0.025 W / m·K). For example, various high-thermal-conductivity resins can be suitably used. For example, if the heat transfer member 25 is made of epoxy resin or silicone resin, a thermal conductivity of 0.5 to 5.5 W / m·K can be achieved. This improves heat dissipation compared to when a gap (air) is provided between the coil end 232 and the first reducer casing 34A or the cover member 61. The form of the heat transfer member 25 is also not particularly limited. For example, a sheet, gel, or other form can be used. It may also be applied to the coil end 232, attached to it, or simply placed thereon.

[0029] By providing such heat transfer members 25, heat from the motor stator 23 is transferred through the motor casing 24 to the first reducer casing 34A or the cover member 61, and simultaneously transferred from each coil end 232 to the first reducer casing 34A or the cover member 61 through each heat transfer member 25. This improves the heat dissipation of the motor 20 (motor stator 23), particularly the heat dissipation of the coil ends 232. Furthermore, because each heat transfer member 25 is elastic, it is possible to hold the retaining plate 38 or the cover member 61 without applying an excessive load, and strict dimensional control is not required.

[0030] [Technical Effects of the First Embodiment] As described above, according to the actuator 1 of the first embodiment, the elastic first heat transfer member 25a is disposed between the coil end 232a of the motor 20 and the first reducer casing 34A of the reducer 30. As a result, heat generated from the coil end 232a is transferred to the first reducer casing 34A through the first heat transfer member 25a. Therefore, unlike conventional methods in which heat was dissipated by the motor alone, the heat dissipation performance of the motor 20 can be suitably improved as an actuator 1. Furthermore, because the heat transfer member 25 is elastic, the heat transfer member 25 can be easily incorporated without the need for strict dimensional control.

[0031] Furthermore, according to the actuator 1 of the first embodiment, the first reducer casing 34A is connected to the mating member E (via the second reducer casing 34B), so heat generated by the coil end 232a is transmitted to the mating member E via the first reducer casing 34A. This further improves the heat dissipation performance of the motor 20.

[0032] Furthermore, according to the actuator 1 of the first embodiment, the first heat transfer member 25a is sandwiched between the coil end 232a and the first reducer casing 34A in a state where it is more compressed (a state where its axial dimension is smaller) than before assembly, which further improves the heat transfer effect from the coil end 232a to the first reducer casing 34A through the first heat transfer member 25a.

[0033] Furthermore, according to the actuator 1 of the first embodiment, the first heat transfer member 25a is in contact with the first reducer casing 34A and the retaining plate 38 that is disposed on the inner circumferential side of the first reducer casing 34A and that axially retains the external gear 32A (reduction member). This allows the first heat transfer member 25a to suitably hold the retaining plate 38 while transmitting heat from the coil end 232a to the first reducer casing 34A.

[0034] Furthermore, according to the actuator 1 of the first embodiment, the axial compression of the first heat transfer member 25a between the coil end 232a and the retaining plate 38 is weaker than the axial compression of the first heat transfer member 25a between the coil end 232a and the first reducer casing 34A. This makes it possible to relatively increase the heat transfer performance of the first heat transfer member 25a to the first reducer casing 34A while favorably holding the retaining plate 38.

[0035] Furthermore, according to the actuator 1 of the first embodiment, an elastic second heat transfer member 25b is also disposed between the anti-output side coil end 232b and the cover member 61 disposed on the anti-output side of the motor 20. This allows heat to be dissipated from the anti-output side coil end 232b to the cover member 61, further improving the heat dissipation performance of the motor 20.

[0036] Furthermore, according to the actuator 1 of the first embodiment, the first heat transfer member 25a on the output side has higher heat transfer properties than the second heat transfer member 25b on the opposite side from the output side. This makes it possible to improve heat transfer to the output side to which the mating member E is connected, i.e., the side with a larger heat capacity, and ultimately to further improve the heat dissipation properties of the motor 20.

[0037] Second Embodiment Next, a second embodiment of the present invention will be described. Figure 3 is a cross-sectional view showing an actuator 2 according to the second embodiment. The actuator 2 differs from the actuator 1 of the first embodiment in that it includes a flexible meshing reducer 70 instead of the eccentric oscillation reducer 30 in the first embodiment. The following mainly describes this difference, and components similar to those in the first embodiment will be designated by the same reference numerals and their description will be omitted.

[0038] 3, the reducer 70 is a cylindrical flexible mesh reducer, and is disposed on the output side of the motor 20. Specifically, the reducer 70 includes a vibrator 71, an external gear 72, a first internal gear 73G, a second internal gear 74G, a first reducer casing 73A, a second reducer casing 73B, and an internal gear member 74.

[0039] The vibrator 71 is provided on a portion of the rotating shaft 21 that extends into the reducer 70, and has a non-circular (e.g., elliptical) outer shape in a cross section perpendicular to the central axis Ax. The external gear 72 is a flexible cylindrical member centered on the central axis Ax, and has teeth on its outer periphery. The external gear 72 is rotatable relative to the vibrator 71 by a vibrator bearing 71B arranged between the external gear 72 and the vibrator 71, and is flexibly deformed by the rotation of the vibrator 71.

[0040] The first internal gear 73G and the second internal gear 74G rotate around the central axis Ax around the vibrator 71. The first internal gear 73G and the second internal gear 74G are arranged side by side in the axial direction and mesh with the external gear 72. The first internal gear 73G and the second internal gear 74G are configured by providing internal teeth at corresponding locations on the inner periphery of the first reducer casing 73A and the internal gear member 74. The first reducer casing 73A covers the outer periphery of the external gear 72. The first reducer casing 73A is fastened together with the brake casing 48, the cover member 61, and the motor casing 24 by fastening screws 64. The internal gear member 74 is connected to an output member 77 arranged on its output side. The output member 77 rotatably supports the rotating shaft 21 via a bearing 75. The output member 77 is connected to a driven member (not shown).

[0041] The second reducer casing 73B is disposed on the output side of and connected to the first reducer casing 73A. The second reducer casing 73B covers the outer periphery of the internal gear member 74 and rotatably supports the internal gear member 74 via a main bearing 76B (e.g., a cross roller bearing). The second reducer casing 73B is fixed to the mating member E together with the first reducer casing 73A.

[0042] A retaining plate 78 is disposed on the non-output side of the external gear 72 and the vibrator bearing 71B to restrict their movement toward the non-output side. The retaining plate 78 is configured similarly to the retaining plate 38 of the first embodiment. It includes a disk portion 78a disposed perpendicular to the axial direction, a cylindrical portion 78b extending from the inner peripheral end of the disk portion 78a toward the non-output side, and an extending portion 78c extending from the non-output side end of the cylindrical portion 78b toward the inner peripheral side. The outer peripheral portion of the disk portion 78a is held (or fitted) in the first reducer casing 73A, and the non-output side surface is substantially flush with the surface of the first reducer casing 73A. The cylindrical portion 78b has a tapered shape that gradually decreases in diameter from the output side toward the non-output side. The extending portion 78c has an outer diameter larger than the outer diameter of the stepped portion 21a of the rotating shaft 21 and an inner diameter smaller than the outer diameter of the stepped portion 21a. The stepped portion 21a of the rotating shaft 21 is disposed on the inner circumferential side of the cylindrical portion 78b and is formed in a stepped shape with an outer diameter that decreases toward the non-output side. A retaining ring 79 fitted into a circumferential groove of the rotating shaft 21 is disposed on the axially opposite side of the extended portion 78c from the stepped portion 21a. The cylindrical portion 78b and extended portion 78c of the retaining plate 78, the stepped portion 21a of the rotating shaft 21, and the retaining ring 79 form a labyrinth seal. This provides an appropriate seal between the motor 20 and the reducer 70 with a compact and low-loss configuration compared to when an oil seal is provided in this portion, and prevents the leakage of lubricant from the reducer 70.

[0043] With this configuration, in the reducer 70, as the rotating shaft 21 output from the motor 20 rotates, the vibrator 71, which is integral with the rotating shaft 21, also rotates, and this motion is transmitted to the external gear 72. At this time, the external gear 72 is restricted to a shape that follows the outer circumferential surface of the vibrator 71 and bends into an elliptical shape when viewed from the axial direction. Furthermore, because the external gear 72 is meshed with the fixed first internal gear 73G at its major axis, it does not rotate at the same rotational speed as the vibrator 71, and the vibrator 71 rotates relatively inside the external gear 72. Then, with this relative rotation, the external gear 72 is bent and deformed such that the major axis position and minor axis position move circumferentially. The period of this deformation is proportional to the rotation period of the vibrator 71. When the external gear 72 flexibly deforms, the position of its major axis moves, causing the meshing position between the external gear 72 and the first internal gear 73G to change in the rotational direction, causing the external gear 72 to rotate and be decelerated at a reduction ratio corresponding to the difference in the number of teeth between the external gear 72 and the first internal gear 73G. For example, if the external gear 72 has 100 teeth and the first internal gear 73G has 102 teeth, the speed is reduced to 1 / 50. Meanwhile, because the external gear 72 also meshes with the second internal gear 74G, the meshing position between the external gear 72 and the second internal gear 74G also changes in the rotational direction due to the rotation of the vibration exciter 71. Here, if the number of teeth of the second internal gear 74G and the number of teeth of the external gear 72 are the same, the external gear 72 and the second internal gear 74G do not rotate relative to each other, and the rotational motion of the external gear 72 is transmitted to the second internal gear 74G at a reduction ratio of 1:1. As a result, the rotational motion of the vibrator 71 is decelerated and transmitted to the internal gear member 74 and the output member 77, and this rotational motion is output to the driven member.

[0044] Furthermore, in the actuator 2 of the second embodiment, the first heat transfer member 25a arranged on the coil end 232a of the motor 20 contacts the first reducer casing 73A and the pressing plate 78, instead of the first reducer casing 34A and the pressing plate 38 in the first embodiment. As in the first embodiment, the first heat transfer member 25a transfers heat generated by the coil end 232a to the first reducer casing 73A while holding the pressing plate 78.

[0045] The actuator 2 of the second embodiment configured as above can also achieve the same effects as those of the first embodiment.

[0046] <Others> Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above embodiments, a center crank type eccentric oscillating reducer and a cylindrical type flexible mesh reducer are exemplified as reducers. However, the type of reducer according to the present invention is not particularly limited, and may be, for example, a cup type or top hat type flexible mesh reducer, a distribution type eccentric oscillating reducer, a simple planetary reducer, or the like, or may be a parallel axis reducer or an orthogonal reducer.

[0047] In addition, the details shown in the above embodiment can be modified as appropriate without departing from the spirit of the invention.

[0048] As described above, the present invention is useful for improving the heat dissipation performance of a motor.

[0049] REFERENCE SIGNS LIST 1, 2 Actuator 20 Motor 21 Rotating shaft 23 Motor stator 24 Motor casing 25 Heat transfer member 25a First heat transfer member 25b Second heat transfer member 30 Reducer 32A, 32B External gear (gear member) 33p Inner pin 34A First reducer casing 34B Second reducer casing 38 Retaining plate 40 Brake 50 Circuit section 61 Cover member 62 Bearing 63 Oil seal 70 Reducer 71B Vibrator bearing 72 External gear (gear member) 73A First reducer casing 73B Second reducer casing 78 Retaining plate 231 Stator core 232, 232a, 232b Coil end Ax Central axis E Counter member

Claims

1. An actuator comprising a motor and a reducer connected to each other, and an elastic heat transfer member disposed between a coil end of the motor and a reducer casing of the reducer.

2. The actuator according to claim 1, wherein the reducer casing is connected to a mating member.

3. The actuator according to claim 1 or 2, wherein the heat transfer member is sandwiched between the coil end and the reducer casing in a state that is more compressed than before assembly.

4. An actuator as claimed in any one of claims 1 to 3, wherein the reducer has a pressure plate arranged inside the reducer casing to restrict axial movement of the gear member, and the heat transfer member is in contact with the reducer casing and the pressure plate.

5. The actuator according to claim 4, wherein compression of the heat transfer member between the coil end and the retaining plate is weaker than compression of the heat transfer member between the coil end and the reducer casing.

6. An actuator according to any one of claims 1 to 5, wherein the coil end is resin-molded, and the heat transfer member is sandwiched between the resin that molds the coil end and the reducer casing.

7. An actuator as claimed in any one of claims 1 to 6, wherein the motor has another coil end on the opposite side to the reducer, and another elastic heat transfer member is arranged between the other coil end and a cover member arranged on the opposite side to the reducer than the coil end.

8. The actuator according to claim 7, wherein the heat transfer member has a higher heat transfer property than the other heat transfer members.

Images