JP-7854817-B2 - Actuator

Inventors

• 重見 貴夫
• 守谷 幸次

Assignees

• 住友重機械工業株式会社

Dates

Publication Date

20260507

Application Date

20220207

Claims (7)

1. It comprises a motor and a reduction gear connected to each other, An elastic heat transfer member is placed between the coil end of the motor and the reduction gear casing of the reduction gear . The reduction gear has a retaining plate positioned inside the reduction gear casing that restricts the axial movement of the gear members. The heat transfer member is in contact with the gearbox casing and the retaining plate. Actuator.
2. The aforementioned reduction gear casing is connected to the mating member, The actuator according to claim 1.
3. The heat transfer member is sandwiched between the coil end and the reduction gear casing in a compressed state compared to before assembly. The actuator according to claim 1 or claim 2.
4. The compression of the heat transfer member between the coil end and the retaining plate is weaker than the compression of the heat transfer member between the coil end and the reduction gear casing. The actuator according to any one of claims 1 to 3 .
5. The coil end is resin-molded, The heat transfer member is sandwiched between the resin molding the coil end and the gearbox casing. The actuator according to any one of claims 1 to 4 .
6. The motor has another coil end on the side opposite to the reduction gear side, An elastic heat transfer member is positioned between the other coil end and the cover member located on the side opposite the reduction gear than the coil end. The actuator according to any one of claims 1 to 5 .
7. The heat transfer member described above has higher heat transfer properties than the other heat transfer members described above. The actuator according to claim 6 .

Description

This invention relates to an actuator. Conventionally, actuators comprising a motor and a reduction gear are known (see, for example, Patent Document 1). In this type of actuator, motor heat generation is a problem. While it's common practice to dissipate heat from the casing (housing) by adding heat sinks, there was room for improvement in the cooling performance (heat dissipation). Japanese Patent Publication No. 2021-97430 This is a cross-sectional view showing an actuator according to the first embodiment.This is a magnified view of the area around the motor in Figure 1.This is a cross-sectional view showing an actuator according to the second embodiment. The embodiments of the present invention will be described in detail below with reference to the drawings. <First Embodiment> Figure 1 is a cross-sectional view showing an actuator 1 according to the first embodiment of the present invention, and Figure 2 is an enlarged view of the area around the motor 20. As shown in Figure 1, the actuator 1 according to the first embodiment includes a motor 20, a reduction gear 30, a brake 40, and a circuit unit 50. The application of the actuator 1 is not particularly limited, but it may be incorporated into the joints of, for example, industrial robots, collaborative robots, or service robots. In the following explanation, 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 rotational direction around the central axis Ax is referred to as the "circumferential direction." Furthermore, within the axial direction, the side connected to the driven member (not shown) (left side in the diagram) is referred to as the "output side (load side)," and the side opposite the output side (right side in the diagram) is referred to as the "anti-output side (anti-load side)." [Motor Configuration] The motor 20 comprises a rotating shaft 21, a motor rotor 22, a motor stator 23, and a motor casing 24. The rotating shaft 21 is positioned to pass through the center of the gearbox 30 to the brake 40 and is supported so as to be rotatable around the central axis Ax. The motor rotor 22 is fixed to the outer surface of the rotating shaft 21 and rotates integrally with the rotating shaft 21. The motor rotor 22 has permanent magnets, such as neodymium magnets, on its outer surface. The motor stator 23 is constructed by winding coils around a stator core 231, which is made of laminated steel plates, for example. The motor stator 23 is arranged concentrically on the outer circumference of the motor rotor 22. Coil ends 232, in which the coils wound around the stator core 231 are exposed, protrude from both axial sides of the motor stator 23. The coil ends 232 are resin-molded throughout. Elastic heat transfer members 25 are sandwiched between the output coil end 232a and the first reducer casing 34A of the reducer 30, and between the non-output coil end 232b and the cover member 61. Details of the contact state of these heat transfer members 25 will be described later. The motor casing 24 covers the outer circumference of the motor rotor 22 and the motor stator 23, with the motor stator 23 fitted inside its inner surface. The motor casing 24 is not particularly limited, but is made of aluminum primarily for the purpose of weight reduction and improved cooling. The type of motor 20 is not particularly limited; for example, it may be an induction motor instead of a permanent magnet motor. [Configuration of the gearbox] The reduction gear 30 is a center-crank type eccentric oscillating reduction gear and is located on the output side of the motor 20. Specifically, the reduction gear 30 comprises a plurality (two) of eccentric bodies 31a, 31b, external gears 32A, 32B, first to third output shafts 33A to 33C, and a first reduction gear casing 34A and a second reduction gear casing 34B. The eccentric bodies 31a and 31b are provided on the outer circumferential 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 reduction gear, but the output shaft of the motor and the input shaft of the reduction gear may be separate and connected to each other. The external gears 32A and 32B have multiple internal pin holes spaced circumferentially 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 and 32B are rotatably supported relative to the eccentric bodies 31a and 31b by eccentric bearings 35a and 35b, respectively, positioned between them, and oscillate with the rotation of the eccentric bodies 31a and 31b. The first output shaft 33A is located on the outer circumference of the rotating shaft 21 and on the output side of the external gears 32A and 32B. The second output shaft 33B is located on the output side of the first outp