Rotation mechanism and robot

Abstract

To provide a rotation mechanism and robot, for which assembly and disassembly work efficiency can be improved and which can be operated stably and extend the product service life.SOLUTION: A speed reduction mechanism 1B according to an embodiment includes an output shaft 9, carriers 13, 14 each of which has an output shaft hole 13b, 14b, and oscillating gears 11, 12 each of which has an output shaft insertion hole 25a, 25b. The output shaft holes 13b, 14b and the output shaft insertion holes 25a, 25b are inserted with the output shaft 9 and have inner peripheral surfaces contacted with the output shaft 9. The surface roughness Ra of the inner peripheral surfaces of the output shaft holes 13b, 14b and output shaft insertion holes 25a, 25b is equal to or less than 1.6 μm, and the static friction coefficient of the inner peripheral surfaces against the output shaft 9 is equal to or less than 0.2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a rotation mechanism and a robot. [Background technology]

[0002] Collaborative robots that share a workspace with a worker have been known for some time. Among these collaborative robots, for example, articulated collaborative robots are provided with a speed reduction mechanism as a rotation mechanism at a joint where two arms are connected, and further provided with an electric motor or the like that applies a rotational force to the speed reduction mechanism. By reducing the rotational force of the electric motor and outputting it, a large output torque can be applied to one of the two arms relative to the other arm.

[0003] The reduction mechanism used is, for example, an eccentric oscillating reduction mechanism with high rotational position accuracy and load resistance. This type of reduction mechanism includes, for example, a housing with an internal gear formed on its inner circumferential surface, an oscillating gear (external gear) that meshes with the internal gear and rotates oscillatingly, an input crankshaft (first rotating part) that has an eccentric part (eccentric body) that rotatably supports the oscillating gear and transmits rotational force to the oscillating gear, an output shaft (carrier pin) to which the rotational force of the oscillating gear is transmitted, and a support part (carrier) connected to the output shaft. The support part is rotatably supported by the housing via a plain bearing. The output shaft is press-fitted into a hole (press-fit hole) formed in the support part and is integrated with the support part. As a result, when the rotational force of the oscillating gear is transmitted to the output shaft, the support part rotates relative to the housing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-17362 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned conventional technology, the output shaft is press-fitted into the support part, which makes assembling and disassembling the reduction gear mechanism cumbersome. Furthermore, because the output shaft cannot freely rotate relative to the support part, the limit PV values ​​of the support part and the output shaft are low, which can lead to problems such as seizure in the support part and the output shaft. This makes it difficult to operate the reduction gear mechanism stably, which can shorten the product life of the reduction gear mechanism.

[0006] The present invention provides a rotation mechanism and a robot that can improve the ease of assembly and disassembly, and can operate stably to extend the product life. [Means for solving the problem]

[0007] A rotation mechanism according to one embodiment of the present invention comprises a shaft, and a rotating body having a shaft insertion hole into which the shaft is inserted and whose inner surface is in contact with the shaft, the rotating body being rotatable relative to the shaft, wherein the surface roughness Ra of the inner surface is 1.6 μm or less, and the static friction coefficient of the inner surface with respect to the shaft is 0.2 or less.

[0008] This configuration improves the ease of assembly and disassembly of the rotor and shaft. Furthermore, the surface roughness Ra of the rotor's inner peripheral surface is set to 1.6 μm or less, and the static friction coefficient of the rotor's inner peripheral surface with respect to the shaft is set to 0.2 or less. This reduces the sliding resistance of the shaft against the rotor, and increases the limit PV value of the rotor. This allows for stable operation of the rotation mechanism and extends the product life.

[0009] In the above configuration, the rotating body may be configured such that at least the periphery of the shaft, including the inner circumferential surface, is made of resin, and the shaft is made of metal.

[0010] The above configuration comprises an internal gear having internal teeth, an oscillating gear having external teeth that mesh with the internal teeth of the internal gear and that rotates in an oscillating manner, an input crankshaft that has an eccentric portion that rotatably supports the oscillating gear and transmits rotational force to the oscillating gear, an output shaft to which the rotational force of the oscillating gear is transmitted, and a support portion that rotatably supports both axial ends of the output shaft, wherein the shaft is the output shaft, the rotating body is the oscillating gear and the support portion, and the shaft insertion hole may be a gear-side shaft hole formed in the oscillating gear and a support portion-side shaft hole formed in the support portion.

[0011] In the above configuration, a shim may be provided on at least one of both axial ends of the output shaft to position the output shaft in the axial direction.

[0012] In the above configuration, the shim may include an elastic shim that is elastically deformable.

[0013] In the above configuration, the shim may have an annular spacer into which the output shaft is inserted.

[0014] In the above configuration, the internal gear comprises a cylindrical case and a plurality of internal pins arranged circumferentially on the inner surface of the case, and the thermal conductivity of the case may be higher than the thermal conductivity of the oscillating gear.

[0015] In the above configuration, the internal gear comprises a cylindrical case and a plurality of internal pins arranged circumferentially on the inner surface of the case, and the thermal conductivity of the case may be higher than the thermal conductivity of the internal pins.

[0016] A rotation mechanism according to another aspect of the present invention comprises an internal gear having internal teeth, an oscillating gear formed from resin and having external teeth that mesh with the internal teeth of the internal gear and that rotates in an oscillating manner, an input crankshaft formed from metal and having an eccentric portion that rotatably supports the oscillating gear and transmits rotational force to the oscillating gear, an output shaft formed from metal to which the rotational force of the oscillating gear is transmitted, and support portions formed from resin that rotatably support both axial ends of the output shaft.

[0017] With this configuration, when an eccentric oscillating reduction mechanism is used as the rotation mechanism, the coefficient of static friction between the inner circumferential surfaces of the gear-side shaft hole and the support-side shaft hole and the output shaft can be easily reduced. Furthermore, the limit PV values ​​of the oscillating gear and the support can be easily increased. This allows the rotation mechanism to operate stably, extending its product life. Furthermore, by forming the output shaft from metal, the rigidity of the output shaft can be increased, further stabilizing the operation of the rotation mechanism and extending its product life.

[0018] A robot according to another aspect of the present invention comprises a first member, a second member, and a rotation mechanism provided between the first member and the second member and rotating the second member relative to the first member, the rotation mechanism comprising: an internal gear having internal teeth; an oscillating gear formed from resin and having external teeth that mesh with the internal teeth of the internal gear and that rotates in an oscillating manner; an input crankshaft formed from metal and having an eccentric portion that rotatably supports the oscillating gear and transmits rotational force to the oscillating gear; an output shaft formed from metal and to which the rotational force of the oscillating gear is transmitted; and support portions formed from resin that rotatably support both axial ends of the output shaft.

[0019] By configuring it in this way, it is possible to provide a robot that can operate stably and extend its product life. [Effects of the Invention]

[0020] The above-described rotation mechanism and robot can improve the ease of assembly and disassembly, and can operate stably to extend the product life. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic configuration diagram of a collaborative robot according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a schematic configuration diagram of a second reduction mechanism according to the first embodiment of the present invention. [Figure 3] FIG. 6 is a schematic configuration diagram of a speed reduction mechanism according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0022] Next, an embodiment of the present invention will be described with reference to the drawings.

[0023] <Collaborative robots> FIG. 1 is a schematic diagram of a collaborative robot 100. In the following description, the vertical and horizontal directions of the collaborative robot 100 refer to the vertical and horizontal directions when the collaborative robot 100 is placed on an installation surface F.

[0024] As shown in FIG. 1, the collaborative robot 100 includes a base unit (an example of the first or second member in the claims) 101 placed on an installation surface F, a rotating head (an example of the first or second member in the claims) 102 provided on the base unit 101, an arm unit (an example of the first or second member in the claims) 103 rotatably attached to the upper part of the rotating head (an example of the first or second member in the claims), and an arm unit (an example of the first or second member in the claims) 103 attached to the upper part of the rotating head (an example of the first or second member in the claims). The arm unit 103 includes reduction mechanisms 1A, 1B, 1C (first reduction mechanism 1A, second reduction mechanism 1B, third reduction mechanism 1C) assembled to joints 106a, 106b, 106c (first joint 106a, second joint 106b, third joint 106c) of the arm unit 103, servo motors 107, 108, 109 (first servo motor 107, second servo motor 108, third servo motor 109) as drive sources, and an end effector 110 attached to the arm unit 103.

[0025] The rotary head 102 is connected to the base part 101 so as to be rotatable about a first rotation axis L1. This connected part is a first joint part 106a, and a first reduction mechanism 1A and a first servo motor 107 are assembled to a first joint part 106ad. The first rotation axis L1 coincides with, for example, the vertical direction. The rotation of the first servo motor 107 is transmitted to the rotating head 102 via the first reduction gear mechanism 1A. As a result, the rotating head 102 is driven to rotate around the first rotation axis L1 relative to the base part 101.

[0026] The arm unit 103 is made up of, for example, two arms 111 and 112 (a first arm 111 and a second arm 112) that are long in one direction. Of the two arms 111 and 112, one end of the first arm 111 is connected to the upper part of the rotary head 102 so as to be rotatable about a second rotation axis L2. This connected part is the second joint part 106b, and the second reduction mechanism 1B and the second servo motor 108 are assembled to the second joint part 106b.

[0027] The second rotation axis L2 coincides with, for example, the horizontal direction. The rotation of the second servo motor 108 is transmitted to the first arm 111 via the second reduction gear mechanism 1B. As a result, the first arm 111 is driven to rotate about the second rotation axis L2 relative to the rotary head 102. For example, the first arm 111 is driven to swing back and forth relative to the base part 101.

[0028] One end of the second arm 112 of the two arms 111, 112 is connected to the other end of the first arm 111 so as to be rotatable about a third rotation axis L3. This connected location is a third joint portion 106c, to which a third reduction mechanism 1C and a third servo motor 109 are attached. The third rotation axis L3 coincides with, for example, the horizontal direction. The rotation of the third servo motor 109 is transmitted to the second arm 112 via the third reduction gear mechanism 1C. As a result, the second arm 112 is driven to rotate about the third rotation axis L3 relative to the first arm 111. For example, the second arm 112 is driven to swing up and down relative to the first arm 111.

[0029] The end effector 110 is attached to the other end of the second arm 112. By driving the rotary head 102, the first arm 111, and the second arm 112, the end effector 110 is driven three-dimensionally.

[0030] The base 101, rotary head 102, first arm 111, and second arm 112 that make up the collaborative robot 100 are made of, for example, an aluminum alloy. The thermal conductivity of aluminum alloy is approximately 201 [W / m·K]. Alternatively, each of these may be made of, for example, a magnesium alloy, carbon fiber reinforced plastic (CFRP), or a resin containing boron nitride to increase thermal conductivity. The thermal conductivity of magnesium alloy is, for example, approximately 51.2 [W / m·K].

[0031] [First embodiment] <Deceleration mechanism> Next, each of the reduction mechanisms 1A to 1C will be described with reference to FIG. The basic configuration of each of the reduction mechanisms 1A to 1C is the same. Therefore, in the following explanation, only the second reduction mechanism 1B of the reduction mechanisms 1A to 1C will be explained, and explanations of the first reduction mechanism 1A and the third reduction mechanism 1C will be omitted.

[0032] FIG. 2 is a schematic diagram of the second reduction mechanism 1B. 2, the second reduction mechanism 1B is a so-called eccentric oscillating type reduction mechanism. The second reduction mechanism 1B includes a cylindrical case (an example of the internal gear in the claims) 2, a carrier (an example of the support portion in the claims) 7 rotatably supported by the case 2, an input crankshaft 8 rotatably supported by the carrier 7, and multiple (e.g., three) output shafts 9, and oscillating gears 11 and 12 (a first oscillating gear 11 and a second oscillating gear 12) rotatably supported by the input crankshaft 8.

[0033] The central axis C1 of the case 2 coincides with the second rotation axis L2. In the following description, the direction parallel to the second rotation axis L2 will be referred to as the axial direction, the direction around the second rotation axis L2 will be referred to as the circumferential direction, and the direction perpendicular to the axial and circumferential directions will be referred to as the radial direction.

[0034] The case 2 is made of, for example, an aluminum alloy. Alternatively, the case 2 may be made of, for example, a magnesium alloy, carbon fiber reinforced plastic (CFRP), or a resin containing boron nitride to increase thermal conductivity. The thermal conductivity of the case 2 is preferably higher than that of the internal pin 6, which will be described later. An outer flange portion 4 that protrudes radially outward is integrally formed in the axial center of the outer peripheral surface 2a of the case 2. The outer flange portion 4 has a rectangular cross section along the axial direction.

[0035] The outer flange portion 4 has a plurality of bolt holes 4a that penetrate in the axial direction and are formed at equal intervals around the circumference. A rotating head 102 is placed on the outer flange portion 4, for example, from the axial outside. Then, a bolt 5 is inserted into the bolt hole 4a from the side of the outer flange portion 4 opposite the rotating head 102. The bolt 5 is tightened into the female thread portion 102a of the rotating head 102, thereby fixing the case 2 to the rotating head 102.

[0036] On both axial sides of the inner peripheral surface 2b of the case 2, expanded diameter portions 3a, 3b (first expanded diameter portion 3a, second expanded diameter portion 3b) are formed via steps 3c, 3d (first stepped portion 3c, second stepped portion 3d), respectively. The inner diameter of each expanded diameter portion 3a, 3b is larger than the inner diameter of the inner peripheral surface 2b of the case 2. A carrier 7 is provided on each expanded diameter portion 3a, 3b.

[0037] Furthermore, a plurality of internally toothed pins (an example of the internally toothed gear in the claims) 6 are provided on the inner peripheral surface 2b of the case 2 between the two step portions 3c, 3d. The internally toothed pins 6 are formed of, for example, metal. Alternatively, the internally toothed pins 6 can be formed of a highly thermally conductive resin, a non-metal, or the like. The internally toothed pins 6 may also be formed of a resin containing carbon nanotubes (CNTs) or boron nitride nanotubes (BNNTs). Furthermore, the internally toothed pins 6 may be formed of an iron-based metal such as bearing steel. The internally toothed pins 6 may also be formed of carbon fiber reinforced plastic (CFRP).

[0038] The internal tooth pin 6 is formed in a cylindrical shape. However, this is not limited thereto, and the internal tooth pin 6 may be a hollow member. The internal tooth pin 6 may be a member with a multilayer structure in which a core material is wrapped with a surface material. For example, one of the core material and the surface material of the internal tooth pin 6 may be an iron-based metal, and the other may be a copper-based or aluminum-based metal. In this case, it is possible to achieve both mechanical properties and thermal properties. As another example, one of the core material and the surface material of the internal tooth pin 6 may be made of metal, and the other may be made of resin. The internal tooth pin 6 may also be made of sintered metal.

[0039] The axial direction of the internal pins 6 coincides with the central axis C1 of the case 2. The internal pins 6 are arranged at equal intervals in the circumferential direction. The internal pins 6 function as internal teeth that mesh with the oscillating gears 11 and 12.

[0040] The carrier 7 consists of a first carrier (shaft flange) 13 provided on the first enlarged diameter portion 3a on the rotating head 102 side of the two enlarged diameter portions 3a, 3b formed on the case 2, and a second carrier (hold flange) 14 provided on the second enlarged diameter portion 3b on the axially opposite side of the first enlarged diameter portion 3a. Each of the carriers 13 and 14 is formed in a disk shape. The outer circumferential surface of each of the carriers 13 and 14 is slidably fitted into the corresponding enlarged diameter portion 3a and 3b. Each of the carriers 13 and 14 is positioned in the axial direction by abutting against the corresponding stepped portion 3c and 3d.

[0041] Each of the carriers 13, 14 is formed of, for example, a resin. For example, each of the carriers 13, 14 can be formed of POM (polyacetal). Also, each of the carriers 13, 14 may be formed of a resin other than POM, such as PAEK (Polyaryl Ether Ketones), typified by PEEK (poly Ether Ether Ketone). The resin may be PPS (Poly Phenylene Sulfide) or a resin blended with PPS. Each of the carriers 13, 14 may be formed of carbon fiber reinforced plastic (CFRP). For example, the thermal conductivity of PPS is about 0.2 [W / m·K]. The thermal conductivity of PPS containing boron nitride is, for example, about 2.6 [W / m·K]. Also, the linear expansion coefficient of each of the carriers 13, 14 is, for example, about 1 / 2 to 1 / 4 of an aluminum alloy (23 to 24 (×10 -6 / °C) or higher.

[0042] Input shaft holes 13a, 14a that penetrate in the axial direction are formed in the radial center of each carrier 13, 14. The input crankshaft 8 is inserted into these input shaft holes 13a, 14a. Bearings 15a, 15b (first bearing 15a and second bearing 15b) are provided in the input shaft holes 13a, 14a, respectively. Ball bearings, for example, are used as the bearings 15a, 15b. The input crankshaft 8 is rotatably supported by each of the carriers 13, 14 via these bearings 15a, 15b. The rotation axis of the input crankshaft 8 coincides with the central axis C1 (second rotation axis L2) of the case 2.

[0043] Each carrier 13, 14 has a plurality of (e.g., three) output shaft holes (an example of a shaft insertion hole or a support portion-side shaft hole in the claims) 13b, 14b formed at equal intervals in the circumferential direction around the input shaft hole 13a, 14a. The output shaft 9 is inserted into these output shaft holes 13b, 14b. The surface roughness Ra of the inner peripheral surface of the output shaft holes 13b, 14b is 1.6 μm or less. The static friction coefficient of the inner peripheral surface of the output shaft holes 13b, 14b with respect to the output shaft 9 is 0.2 or less.

[0044] Of the two carriers 13, 14, a shim accommodating recess 41 is formed coaxially with the output shaft hole 13b on one surface 13c of the first carrier 13 opposite the second carrier 14. The shim accommodating recess 41 is open on the one surface 13c side and communicates with the output shaft hole 13b.

[0045] An annular elastic shim 42 (an example of a shim in the claims) is housed in the shim housing recess 41. The inner diameter of the elastic shim 42 is approximately the same as or slightly larger than the inner diameter of the output shaft hole 13b. The elastic shim 42 is made of rubber or the like and is elastically deformable. The elastic shim 42 may be made of a material other than rubber as long as it is made of a material that is elastically deformable. For example, a wave washer may be used as the elastic shim 42 instead of rubber.

[0046] An annular spacer (an example of a shim in the claims) 43 is disposed on the elastic shim 42. The inner diameter of the spacer 43 is approximately the same as or slightly larger than the inner diameter of the output shaft hole 13b. The spacer 43 is made of, for example, metal. The elastic shim 42 and the spacer 43 are used to position the output shaft 9 relative to the carriers 13 and 14 (details will be described later).

[0047] Of the two carriers 13, 14, a recess 16 is formed coaxially with the output shaft hole 14b on one surface 14c of the second carrier 14 opposite to the first carrier 13. The recess 16 is open on the one surface 14c side and communicates with the output shaft hole 14b. The recess 16 can be filled with, for example, grease 17. The grease 17 is used to dissipate heat transmitted to the output shaft 9. The thermal conductivity of the grease 17 is higher than the thermal conductivity of the oscillating gears 11 and 12 and the second carrier 14. The thermal conductivity of the grease 17 is 5 W / m K or higher.

[0048] The output shaft 9 inserted into the output shaft holes 13b and 14b is made of, for example, an aluminum alloy. The output shaft 9 is not limited to an aluminum alloy and can also be made of stainless steel. The thermal conductivity of stainless steel is approximately 16.7 W / m K. Alternatively, for example, an iron-based metal can be used for the output shaft 9. As the iron-based metal, carbon steel, bearing steel, or the like can be used depending on the desired characteristics. For example, the thermal conductivity of S45C iron is approximately 45 W / m K.

[0049] A first end 9a of the output shaft 9 on the first carrier 13 side protrudes slightly from a surface 13c of the first carrier 13 opposite the second carrier 14. An elastic shim 42 and a spacer 43 are attached to the first end 9a of the output shaft 9. A first retaining ring 18a is attached to the first end 9a of the output shaft 9 from above the spacer 43. The first retaining ring 18a abuts against the spacer 43, restricting movement of the output shaft 9 toward the second carrier 14 side.

[0050] A second end 9b of the output shaft 9 on the second carrier 14 side is located slightly lower than one surface 14c of the second carrier 14. In other words, the second end 9b of the output shaft 9 is housed within a recess 16 of the second carrier 14. A second retaining ring 18b is attached to the second end 9b of the output shaft 9. The second retaining ring 18b is also housed within the recess 16. When the second retaining ring 18b hits the bottom surface 16a of the recess 16, movement of the output shaft 9 toward the first carrier 13 side is restricted.

[0051] That is, the elastic shim 42, the spacer 43, and the retaining rings 18a, 18b function to position the output shaft 9 relative to the carriers 13, 14. Of these, the elastic shim 42 and the spacer 43 function to absorb manufacturing errors of the case 2, the carriers 13, 14, and the output shaft 9, and adjust the position of the output shaft 9 relative to the carriers 13, 14. In other words, the axial thickness of the elastic shim 42 and the spacer 43 is adjusted according to the magnitude of axial play of the output shaft 9 relative to the carriers 13, 14, thereby reducing axial play of the output shaft 9 relative to the carriers 13, 14. This play is play caused by play that allows the output shaft 9 to move axially relative to the carriers 13, 14 due to manufacturing errors of the case 2, the carriers 13, 14, and the output shaft 9.

[0052] The axial thickness of the elastic shim 42 is determined so that it is in a slightly compressed state. As a result, the restoring force generated in the attached elastic shim 42 biases the first carrier 13 toward the second carrier 14. As a result, rattle of the carriers 13, 14 and the output shaft 9 is reliably suppressed. Furthermore, even if the axial rattle of the output shaft 9 relative to the carriers 13, 14 increases due to aging or other reasons, this rattle can be absorbed by the elastic shim 42. Furthermore, biasing the first carrier 13 toward the second carrier 14 also applies preload to the bearings 15a, 15b provided in the input shaft holes 13a, 14a of the carriers 13, 14.

[0053] Furthermore, axial movement of the output shaft 9 relative to each of the carriers 13, 14 is restricted; in other words, axial movement of each of the carriers 13, 14 is restricted. Therefore, each of the carriers 13, 14 remains fitted in the corresponding expanded diameter portion 3a, 3b of the case 2. Also, each of the carriers 13, 14 and each of the output shafts 9 are integrated. Since the output shaft 9 is inserted into the output shaft holes 13b, 14b of each of the carriers 13, 14, it is arranged around the input crankshaft 8. The input crankshaft 8 is made of, for example, an aluminum alloy, similar to the output shaft 9. Alternatively, the input crankshaft 8 may be made of, for example, stainless steel or various iron-based metals, similar to the output shaft 9.

[0054] A first end 8a of the input crankshaft 8 on the first carrier 13 side protrudes axially outward via a first bearing 15a provided on the first carrier 13. A second servomotor 108 is connected to this first end 8a. The rotation of the second servomotor 108 is transmitted to the input crankshaft 8.

[0055] A second end 8b of the input crankshaft 8 on the second carrier 14 side is positioned on approximately the same plane as the end face of a second bearing 15b provided on the second carrier 14 on the opposite side from the first carrier 13. The input crankshaft 8 is formed with a first eccentric portion 21a and a second eccentric portion 21b aligned in the axial direction between the bearings 15a and 15b provided on the carriers 13 and 14. The input crankshaft 8 is also formed with an expanded diameter portion 20 between the eccentric portions 21a and 21b, the expanded diameter portion 20 having a diameter larger than that of the eccentric portions 21a and 21b.

[0056] The first eccentric portion 21a is disposed on the first carrier 13 side. The second eccentric portion 21b is disposed on the second carrier 14 side. The eccentric portions 21a, 21b are eccentric from the second rotation axis L2. The eccentric portions 21a, 21b are shifted in phase angle from each other. For example, the eccentric portions 21a, 21b are shifted in phase angle from each other by 180°.

[0057] The eccentric portions 21a and 21b are provided with bearings 15c and 15d (third bearing 15c and fourth bearing 15d), respectively. As with the first bearing 15a and the second bearing 15b, ball bearings are used for these bearings 15c and 15d. The axial distance between the bearings 15c and 15d is regulated by the axial end faces of these bearings 15c and 15d abutting against the enlarged diameter portion 20. The oscillating gears 11 and 12 (first oscillating gear 11 and second oscillating gear 12) are rotatably supported on the eccentric portions 21a and 21b via the bearings 15c and 15d.

[0058] The two oscillating gears 11, 12 are formed, for example, from a resin. For example, the oscillating gears 11, 12 can be formed from POM (polyacetal). In addition, various resins can be used for the oscillating gears 11, 12, similar to the material for forming the carriers 13, 14. Because the oscillating gears 11, 12 are formed from a resin, the thermal conductivity of the output shaft 9 and the input crankshaft 8 is higher than that of the oscillating gears 11, 12. Furthermore, the thermal conductivity of the case 2 is higher than that of the oscillating gears 11, 12. Furthermore, the thermal conductivity of the internal pin 6 is higher than that of the oscillating gears 11, 12.

[0059] The two oscillating gears 11, 12 are arranged at a fixed interval between the two carriers 13, 14. Crankshaft insertion holes 24a, 24b (first crankshaft insertion hole 24a, second crankshaft insertion hole 24b) are formed in the radial centers of the two oscillating gears 11, 12, penetrating the thickness direction and into which the outer peripheral surfaces of the corresponding bearings 15c, 15d are fitted. As a result, the oscillating gears 11, 12 are rotatably supported by the eccentric portions 21a, 21b, respectively, via the bearings 15c, 15d. The oscillating gears 11, 12 are oscillatingly rotated by the eccentric portions 21a, 21b.

[0060] External teeth 23a, 23b that mesh with internal pins 6 provided on the case 2 are formed on the outer peripheries of the two oscillating gears 11, 12. The number of teeth of each of the external teeth 23a, 23b is, for example, one less than the number of internal pins 6. Furthermore, the two oscillating gears 11, 12 are formed with output shaft insertion holes 25a, 25b (first output shaft insertion hole 25a, second output shaft insertion hole 25b; examples of shaft insertion holes and gear-side shaft holes in the claims) at positions corresponding to the output shaft 9, into which the output shaft 9 is inserted. The inner diameter of each output shaft insertion hole 25a, 25b is large enough to allow oscillating rotation of the oscillating gears 11, 12 with the output shaft 9 inserted in the output shaft insertion hole 25a, 25b. Furthermore, the surface roughness Ra of the inner peripheral surfaces of the output shaft insertion holes 25a, 25b is 1.6 μm or less, and the static friction coefficient of the inner peripheral surfaces of the output shaft insertion holes 25a, 25b with respect to the output shaft 9 is 0.2 or less.

[0061] Of the two carriers 13, 14 of the second reduction gear mechanism 1B configured in this manner, for example, a first arm 111 is placed on one surface 14c of the second carrier 14 opposite to the first carrier 13. Then, the first arm 111 is fixed to the first carrier 13 by a bolt (not shown). The first arm 111 is formed with a protrusion 111a that fits into the input shaft hole 14a of the second carrier 14. This positions the first arm 111 in the radial direction relative to the second carrier 14. The protrusion 111a protrudes to an extent that it faces the second bearing 15b and the second end 8b of the input crankshaft 8 with a small gap between them.

[0062] <Operation and Function of Second Reduction Mechanism> Next, the operation and function of the second reduction mechanism 1B will be described. By driving the second servo motor 108, the input crankshaft 8 is rotated. As a result, the oscillating gears 11 and 12 rotatably supported by the eccentric portions 21 a and 21 b are oscillated and rotated. As a result, the internal tooth pin 6 of the case 2 meshes with a portion of the external teeth 23 a and 23 b of the oscillating gears 11 and 12.

[0063] At this time, since the number of teeth of each of the external teeth 23a, 23b is, for example, one less than the number of the internal tooth pins 6, the oscillating gears 11, 12 rotate around their axes such that the meshing points of each of the external teeth 23a, 23b with respect to the internal tooth pins 6 (case 2) are sequentially shifted in the circumferential direction. This rotation is decelerated relative to the rotation of the input crankshaft 8.

[0064] An output shaft 9 is inserted into the output shaft insertion holes 25a, 25b of the oscillating gears 11, 12. Therefore, when the oscillating gears 11, 12 rotate, a rotational force in the rotation direction of the oscillating gears 11, 12 is transmitted to each output shaft 9. Furthermore, each output shaft 9 is rotatably supported by each carrier 13, 14. Therefore, the rotational force of the oscillating gears 11, 12 is transmitted to each carrier 13, 14.

[0065] The outer peripheral surfaces of the carriers 13, 14 are slidably fitted into the corresponding expanded diameter portions 3a, 3b of the case 2. Therefore, the carriers 13, 14 are rotated relative to the case 2. That is, the rotation by the second servo motor 108 is decelerated and output to the carriers 7 (first carrier 13, second carrier 14). A rotary head 102 is fixed to the case 2. Meanwhile, a first arm 111 is fixed to the second carrier 14 of the carriers 13, 14. Therefore, the first arm 111 rotates relative to the rotary head 102 about a second rotation axis L2.

[0066] Here, for example, if the rotation of the first arm 111 (second carrier 14) is restricted, the rotation by the second servo motor 108 is decelerated and output to the case 2. In this case, the rotary head 102 rotates about the second rotation axis L2 relative to the first arm 111. That is, by restricting the rotation of either the case 2 or the carrier 7, the speed reduction mechanisms 1A to 1C allow the other to become the output for each of the servo motors 107 to 109. This operating principle also applies to the first reduction mechanism 1A and the third reduction mechanism 1C.

[0067] The output shaft 9 and each carrier 13, 14 are integrated by inserting the output shaft 9 into output shaft holes 13b, 14b formed in each carrier 13, 14. This allows the output shaft 9 to rotate freely relative to each carrier 13, 14. Moreover, by forming each carrier 13, 14 from resin, it is possible to rotatably support the output shaft 9 on each carrier 13, 14 without providing a bearing separate from each carrier 13, 14.

[0068] In addition, the surface roughness Ra of the inner peripheral surfaces of the output shaft holes 13b, 14b is 1.6 μm or less. The static friction coefficient of the inner peripheral surfaces of the output shaft holes 13b, 14b with respect to the output shaft 9 is 0.2 or less. As a result, the sliding resistance of the output shaft 9 with respect to each of the carriers 13, 14 can be reduced, and the output shaft 9 can rotate smoothly with respect to each of the carriers 13, 14.

[0069] The same can be said for the relationship between each of the oscillating gears 22a, 22b and the output shaft 9. That is, each of the oscillating gears 22a, 22b is made of resin. The surface roughness Ra of the inner peripheral surface of the output shaft insertion holes 25a, 25b formed in each of the oscillating gears 22a, 22b is 1.6 μm or less. Furthermore, the static friction coefficient of the inner peripheral surface of the output shaft insertion holes 25a, 25b with respect to the output shaft 9 is 0.2 or less. Therefore, the output shaft 9 comes into smooth contact with each of the oscillating gears 22a, 22b without providing bearings separate from each of the oscillating gears 22a, 22b.

[0070] By the way, each member generates heat due to meshing between the internal pin 6 and the oscillating gears 11, 12, sliding friction between the case 2 and each carrier 13, 14, sliding friction between each carrier 13, 14 and the output shaft 9, sliding friction between the bearings 15a to 15d, etc. The input crankshaft 8 and the output shaft 9 are made of, for example, an aluminum alloy. The thermal conductivity of the input crankshaft 8 and the output shaft 9 is higher than the thermal conductivity of the oscillating gears 11 and 12.

[0071] For this reason, heat trapped inside the second reduction gear mechanism 1B is actively transferred to the input crankshaft 8 and the output shaft 9. For example, heat from the bearings 15a to 15d and heat from the oscillating gears 11 and 12 is actively transferred to the input crankshaft 8. In addition, heat trapped in the oscillating gears 11 and 12 due to heat transfer to the oscillating gears 11 and 12 by the internally toothed pin 6, the third bearing 15c, and the fourth bearing 15d, and heat from the oscillating gears 11 and 12 themselves, is actively transferred to the output shaft 9.

[0072] The heat transferred to the input crankshaft 8 is distributed throughout the entire axial direction and is transferred to the first end 8a and the second end 8b. The heat is then dissipated through the ends 8a and 8b. Because the second end 8b faces the protrusion 111a of the first arm 111 with a small gap between them, the heat from the second end 8b is also transferred to the first arm 111. The first arm 111 is made of, for example, an aluminum alloy, and has a thermal conductivity equal to or greater than that of the input crankshaft 8 and the output shaft 9. Therefore, the heat transferred from the input crankshaft 8 to the first arm 111 is effectively dissipated.

[0073] On the other hand, the heat transferred to the output shaft 9 is distributed over the entire axial direction and is transferred to the first end 9a and the second end 9b, and is then dissipated through the ends 9a and 9b. Here, a recess 16 is formed in the second carrier 14 around the second end 9b of the output shaft 9. Furthermore, the recess 16 is filled with grease 17. The first arm 111 is disposed so as to close the opening of the recess 16 filled with grease 17, that is, so as to overlap one surface 14c of the second carrier 14. Therefore, heat from the second end 9b of the output shaft 9 is efficiently transferred to the first arm 111 via the grease 17. Therefore, the heat transferred from the output shaft 9 to the first arm 111 is effectively dissipated.

[0074] The case 2 is made of, for example, an aluminum alloy. The internal pin 6 can be made of a metal material, a highly thermally conductive resin, a non-metallic material, or the like. The oscillating gears 11 and 12 are made of, for example, a resin. The thermal conductivity of the case 2 is higher than that of the oscillating gears 11 and 12, and the thermal conductivity of the internal pin 6 is higher than that of the oscillating gears 11 and 12. Therefore, heat generated by the meshing between the internal pin 6 and the oscillating gears 11 and 12 can be actively transferred to the case 2 and the internal pin 6. This prevents heat from being trapped inside the second reduction gear mechanism 1B.

[0075] The first reduction gear mechanism 1A and the third reduction gear mechanism 1C also have the same heat dissipation effect as described above. Heat trapped inside the first reduction gear mechanism 1A and the third reduction gear mechanism 1C is dissipated by the input crankshaft 8 and the output shaft 9. The heat is also transferred to the rotating head 102, the second arm 112, etc. via the input crankshaft 8 and the output shaft 9, and is effectively dissipated. Furthermore, the case 2 and the internal tooth pin 6 prevent heat from being trapped inside the reduction gear mechanisms 1A and 1C.

[0076] As described above, in the above-described reduction gear mechanisms 1A, 1B, and 1C, the surface roughness Ra of the inner circumferential surfaces of the output shaft holes 13b and 14b formed in the respective carriers 13 and 14, which are rotating bodies, is 1.6 μm or less. Also, the static friction coefficient of the inner circumferential surfaces of the output shaft holes 13b and 14b with respect to the output shaft 9 is 0.2 or less. Similarly, the surface roughness Ra of the inner circumferential surfaces of the output shaft insertion holes 25a and 25b formed in the respective oscillating gears 22a and 22b, which are rotating bodies, is 1.6 μm or less. Also, the static friction coefficient of the inner circumferential surfaces of the output shaft insertion holes 25a and 25b with respect to the output shaft 9 is 0.2 or less.

[0077] Therefore, the output shaft 9 can be smoothly and rotatably supported on each of the carriers 13, 14 without providing separate bearings for each of the carriers 13, 14. The output shaft 9 can be brought into smooth contact with each of the oscillating gears 22a, 22b without providing separate bearings for each of the oscillating gears 22a, 22b. In addition, the limit PV values ​​of each of the carriers 13, 14 and each of the oscillating gears 22a, 22b can be increased. This allows the reduction mechanisms 1A, 1B, 1C to operate stably, and extends their product lifespan.

[0078] Since there is no need to provide bearings for contact between the carriers 13, 14 and the output shaft 9 or between the oscillating gears 22a, 22b and the output shaft 9, the reduction mechanisms 1A, 1B, 1C can be made smaller. In addition, the linear expansion coefficient of each carrier 13, 14 is, for example, aluminum alloy (23 to 24 × 10 -6 / °C). On the other hand, the output shaft 9 is formed of, for example, an aluminum alloy. Therefore, even if the temperature of each of the carriers 13, 14 rises due to driving the reduction gear mechanisms 1A, 1B, 1C, the outer diameter of the output shaft 9 does not become too large compared to the inner diameter of the output shaft holes 13b, 14b, and the output shaft 9 can be supported by each of the carriers 13, 14 so as to be smoothly rotatable.

[0079] The output shaft 9 is inserted into the output shaft holes 13b, 14b of the carriers 13, 14. Therefore, compared to when the output shaft 9 is press-fitted into and fixed to the carriers 13, 14, the assembly and disassembly workability of the reduction mechanisms 1A, 1B, 1C can be improved.

[0080] By forming the carriers 13, 14 and the oscillating gears 22a, 22b from resin, the surface roughness Ra of the inner peripheral surfaces of the output shaft holes 13b, 14b and the output shaft insertion holes 25a, 25b can be easily set to 1.6 μm or less. Also, the static friction coefficient of the inner peripheral surfaces of the output shaft holes 13b, 14b and the output shaft insertion holes 25a, 25b with respect to the output shaft 9 can be easily set to 0.2 or less. On the other hand, by forming the output shaft 9 from metal, it is possible to increase the rigidity of the output shaft 9. This allows the reduction mechanisms 1A, 1B, and 1C to operate more stably, thereby extending the product life.

[0081] In the eccentric oscillating type reduction mechanism (reduction mechanism 1A, 1B, 1C), by using the first carrier 13 having the output shaft holes 13b, 14b and the second carrier 14 having the output shaft insertion holes 25a, 25b as described above, it is possible to improve the drive efficiency while reducing the size of each reduction mechanism 1A, 1B, 1C. In addition, the limit PV values ​​of each carrier 13, 14 and each oscillating gear 22a, 22b can be easily increased, and the rigidity of the output shaft 9 can also be increased, ensuring stable operation of each reduction mechanism 1A, 1B, 1C. The product life of each reduction mechanism 1A, 1B, 1C can be extended.

[0082] Additionally, an elastic shim 42 and a spacer 43 are provided on the first end 9a side of the output shaft 9. This allows the output shaft 9 to be positioned easily and accurately relative to the carriers 13, 14. The elastic shim 42 and the spacer 43 can absorb manufacturing errors in the case 2, the carriers 13, 14, and the output shaft 9. The elastic shim 42 and the spacer 43 also allow the position of the output shaft 9 relative to the carriers 13, 14 to be adjusted.

[0083] Two components (elastic shim 42 and spacer 43) are used to adjust the position of output shaft 9, and the combination of these two components can increase the variety of position adjustment methods. This makes it possible to position output shaft 9 with respect to each of carriers 13 and 14 more easily and with higher precision, thereby reducing wobble of the output shaft.

[0084] In particular, the elastic shim 42 is elastically deformed. Therefore, by attaching the elastic shim 42 while compressing it slightly in the axial direction, the restoring force generated in the elastic shim 42 can urge the first carrier 13 toward the second carrier 14. As a result, rattle of the carriers 13, 14 and the output shaft 9 can be reliably suppressed. Furthermore, even if the axial rattle of the output shaft 9 relative to the carriers 13, 14 increases due to aging or the like, this rattle can be absorbed by the elastic shim 42. Furthermore, by urging the first carrier 13 toward the second carrier 14, a preload can be applied to the bearings 15a, 15b provided in the input shaft holes 13a, 14a of the carriers 13, 14.

[0085] In the reduction mechanisms 1A, 1B, and 1C, the thermal conductivity of the case 2 is higher than that of each of the oscillating gears 22a and 22b. Therefore, the heat in the reduction mechanisms 1A, 1B, and 1C can be efficiently dissipated through the case 2. Furthermore, by making the thermal conductivity of the case 2 higher than that of the internal pin 6, the heat trapped in the internal pin 6 can be actively transferred to the case 2. This allows the heat inside the reduction mechanisms 1A, 1B, and 1C to be efficiently dissipated via the case 2.

[0086] By using the above-described speed reduction mechanisms 1A, 1B, and 1C in the joints 106a, 106b, and 106c of the collaborative robot 100, it is possible to stabilize the operation of the collaborative robot 100. In addition, it is possible to extend the product life of the collaborative robot 100.

[0087] In the first embodiment described above, the elastic shim 42 and the spacer 43 are provided on the first end 9a side of the output shaft 9. However, this is not limiting, and the elastic shim 42 and the spacer 43 may be provided on the second end 9b side of the output shaft 9. The elastic shim 42 and the spacer 43 may be provided on both ends 9a, 9b of the output shaft 9. Furthermore, either the elastic shim 42 or the spacer 43 may be provided.

[0088] [Second embodiment] <Deceleration mechanism> Next, a second embodiment will be described with reference to FIG. 1 and based on FIG. 3 is a schematic diagram of a speed reduction mechanism 201 according to the second embodiment. Note that the same components as those in the first embodiment will be denoted by the same reference numerals. Furthermore, in the description of the second embodiment, the same names as those in the first embodiment may be used and the description thereof may be omitted.

[0089] As shown in FIG. 1, the second embodiment is similar to the first embodiment in that a speed reduction mechanism 201 is used in the collaborative robot 100. As shown in FIG. 2, the reduction mechanism 201 of the second embodiment is a so-called eccentric oscillating type reduction mechanism, and is similar to each of the reduction mechanisms 1A, 1B, and 1C of the first embodiment described above in that it includes a case 2, a carrier 7, an input crankshaft 8, an output shaft 9, and oscillating gears 11 and 12.

[0090] The difference between the first and second embodiments described above is that in the first embodiment, an elastic shim 42 is provided on the first end 9a side of the output shaft 9, whereas in the second embodiment, an elastic shim 42 is not provided. That is, the shim storage recess 41 (see FIG. 2) is not formed on the one surface 13c of the first carrier 13, and the one surface 13c of the first carrier 13 is flat over its entirety. Only a spacer 43 is provided on the first end 9a side of the output shaft 9. Even with this configuration, the same effects as those of the first embodiment described above can be achieved.

[0091] The present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the spirit of the present invention. For example, in the above-described embodiment, the reduction mechanism 1A-1C, 201 is used in the collaborative robot 100. However, this is not limited to this. The configuration of the above-described embodiment can be adopted in various robots having two members (a first member and a second member), with the reduction mechanism 1A-1C, 201 provided between the two members, and with the second member rotating relative to the first member.

[0092] In the above-described embodiments, the reduction gear mechanisms 1A to 1C and 201 have been described as examples of gear mechanisms. However, the gear mechanisms are not limited to these. Instead of the reduction gear mechanisms 1A to 1C, the configurations of the above-described embodiments can be employed in various gear mechanisms in which two gears are meshed together and a rotational force is transmitted to one of the two gears, or a shaft is used to transmit the rotational force of the one gear.

[0093] In the above-described embodiments, the reduction gear mechanisms 1A to 1C, 201 are so-called eccentric oscillating type reduction gear mechanisms, and have been described as having one center crankshaft (input crankshaft 8, 208) coaxial with the central axis C1 of the case 2. However, this is not limiting, and the eccentric oscillating type reduction gear mechanism may be configured such that the oscillating gears 11, 12 are oscillated and rotated by rotating multiple input crankshafts 8, 208 in conjunction with each other. In this case, the input crankshaft 8, 208 itself rotates on its own axis while revolving around the central axis C1.

[0094] The above-described collaborative robot 100 has been described as using servo motors 107, 108, and 109 as drive sources. However, this is not limiting, and various drive sources such as electric motors, hydraulic motors, and engines can be used instead of servo motors.

[0095] In the above embodiment, the carriers 13, 14 are formed of, for example, resin. However, this is not limiting, and it is sufficient that the surface roughness Ra of the inner peripheral surface of the output shaft holes 13b, 14b is 1.6 μm or less, and the static friction coefficient of the inner peripheral surface of the output shaft holes 13b, 14b with respect to the output shaft 9 is 0.2 or less.

[0096] For example, each carrier 13, 14 may be formed from a material other than resin, and the inner circumferential surfaces of the output shaft holes 13b, 14b may be coated with a fluororesin. Of each carrier 13, 14, only the periphery of the output shaft 9, including at least the inner circumferential surfaces of the output shaft holes 13b, 14b, may be formed from resin. Alternatively, each carrier may be formed from sintered metal or casting. Only the periphery of the output shaft 9, including the inner circumferential surfaces of the output shaft holes 13b, 14b, may be formed from sintered metal or casting.

[0097] In the above-described embodiment, the elastic shims 42 and the spacers 43 are described as being annular in shape. Furthermore, the elastic shims 42 and the spacers 43 are described as being attached to the first end 9a of the output shaft 9. However, this is not limited thereto, and any shape may be used as long as the elastic shims 42 and the spacers 43 can absorb manufacturing errors of the case 2, the carriers 13 and 14, and the output shaft 9. Furthermore, any shape may be used as long as the elastic shims 42 and the spacers 43 can adjust the position of the output shaft 9 relative to the carriers 13 and 14. For example, the elastic shims 42 and the spacers 43 may be U-shaped. In this case, it is preferable to configure the shim storage recess 41 formed in the first carrier 13 to store not only the elastic shims 42 but also the spacers 43. This configuration can prevent the elastic shims 42 and the spacers 43 from falling off, regardless of their shapes.

[0098] Among the embodiments disclosed in this specification, those that are comprised of multiple objects may be integrated, and conversely, those that are comprised of a single object may be separated into multiple objects. Regardless of whether they are integrated, it is sufficient that they are configured to achieve the object of the invention. [Explanation of symbols]

[0099] 1A, 1B, 1C, 201...Reduction mechanism (rotation mechanism) 2...Case (internal gear) 6...Inner tooth pin (inner tooth) 7...Carrier (rotating body, support part) 8...Input crankshaft 9...Output shaft (shaft) 9a...First end (end) 9b…Second end (end) 11...First oscillating gear (rotating body, oscillating gear) 12... Second oscillating gear (rotating body, oscillating gear) 13...First carrier (rotating body, support part) 13b, 14b...Output shaft hole (shaft insertion hole, support portion side shaft hole) 14...Second carrier (rotating body, support part) 21a...First eccentric part (eccentric part) 21b...Second eccentric part (eccentric part) 23a, 23b…external teeth 25a...First output shaft insertion hole (shaft insertion hole, gear side shaft hole) 25b... Second output shaft insertion hole (shaft insertion hole, gear side shaft hole) 42...Elastic shim (shim) 43...Spacer (shim) 100... Collaborative robot (robot) 101...base portion (first member, second member) 102...Rotating head (first member, second member) 103...Arm unit (first member, second member) 111...First arm (first member, second member) 112...Second arm (first member, second member)

Claims

1. An internal gear having internal teeth; an oscillating gear having external teeth meshed with the internal teeth of the internal gear and oscillatingly rotated; an input crankshaft having an eccentric portion that rotatably supports the oscillating gear and that transmits rotational force to the oscillating gear; an output shaft to which the rotational force of the oscillating gear is transmitted; a support portion that rotatably supports both axial end portions of the output shaft, a gear-side shaft hole is formed in the oscillating gear, into which the output shaft is inserted and into which the output shaft comes into contact with a gear-side inner peripheral surface; a support portion-side shaft hole is formed in the support portion, into which the output shaft is inserted and into which the output shaft comes into contact with a support portion-side inner circumferential surface; a rubber, annular elastic shim fitted to at least one of both axial end portions of the output shaft for axial positioning of the output shaft; a shim accommodating recess formed in the support portion, the shim accommodating recess communicating with the support portion-side shaft hole and coaxially aligned with the support portion-side shaft hole; The elastic shim is fitted into the shim receiving recess, The gear-side inner peripheral surface and the support-side inner peripheral surface have a surface roughness Ra of 1.6 μm or less, and the gear-side inner peripheral surface and the support-side inner peripheral surface have a static friction coefficient with respect to the output shaft of 0.2 or less. Rotation mechanism.

2. The oscillating gear and the support portion are formed of resin around the output shaft, including at least the inner peripheral surface of the gear side and the inner peripheral surface of the support portion side, and the output shaft is formed of metal. The rotation mechanism according to claim 1 .

3. A rotating mechanism as described in claim 1 or claim 2, having an annular spacer into which the output shaft is inserted.

4. The internal gear is A cylindrical case and a plurality of internally toothed pins arranged along a circumferential direction on an inner peripheral surface of the case, The rotation mechanism according to claim 1 , wherein the case has a thermal conductivity higher than that of the oscillating gear.

5. The internal gear is A cylindrical case and a plurality of internally toothed pins arranged along a circumferential direction on an inner peripheral surface of the case, The rotation mechanism according to claim 1 , wherein the case has a thermal conductivity higher than that of the internally toothed pin.

6. an internal gear having internal teeth; an oscillating gear formed of resin, having external teeth that mesh with the internal teeth of the internal gear, and that oscillates and rotates; an input crankshaft made of metal, having an eccentric portion that rotatably supports the oscillating gear, and transmitting a rotational force to the oscillating gear; an output shaft made of metal to which the rotational force of the oscillating gear is transmitted; a support portion formed of resin and configured to rotatably support both axial end portions of the output shaft; Equipped with a gear-side shaft hole is formed in the oscillating gear, into which the output shaft is inserted and into which the output shaft comes into contact with a gear-side inner peripheral surface; a support portion-side shaft hole is formed in the support portion, into which the output shaft is inserted and into which the output shaft comes into contact with a support portion-side inner circumferential surface; a rubber, annular elastic shim fitted to at least one of both axial end portions of the output shaft for axial positioning of the output shaft; a shim accommodating recess formed in the support portion, the shim accommodating recess communicating with the support portion-side shaft hole and coaxially aligned with the support portion-side shaft hole; The elastic shim is fitted into the shim receiving recess. Rotation mechanism.

7. a first member and a second member; a rotation mechanism provided between the first member and the second member and configured to rotate the second member relative to the first member; Equipped with The rotation mechanism includes: an internal gear having internal teeth; an oscillating gear formed of resin, having external teeth that mesh with the internal teeth of the internal gear, and that oscillates and rotates; an input crankshaft made of metal, having an eccentric portion that rotatably supports the oscillating gear, and transmitting a rotational force to the oscillating gear; an output shaft made of metal to which the rotational force of the oscillating gear is transmitted; a support portion formed of resin and configured to rotatably support both axial end portions of the output shaft; Equipped with a gear-side shaft hole is formed in the oscillating gear, into which the output shaft is inserted and into which the output shaft comes into contact with a gear-side inner peripheral surface; a support portion-side shaft hole is formed in the support portion, into which the output shaft is inserted and into which the output shaft comes into contact with a support portion-side inner circumferential surface; a rubber, annular elastic shim fitted to at least one of both axial end portions of the output shaft for axial positioning of the output shaft; a shim accommodating recess formed in the support portion, the shim accommodating recess communicating with the support portion-side shaft hole and coaxially aligned with the support portion-side shaft hole; The elastic shim is fitted into the shim receiving recess. robot.

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