Gear mechanisms and robots

Abstract

To provide a gear mechanism and a robot capable of efficiently suppressing internal temperature rise.SOLUTION: A speed reduction mechanism 1B comprises: a case 2 and an internal tooth pin 6; oscillating gears 11, 12 meshed with the internal tooth pin 6; an input crankshaft 8 that transmits rotational force to the oscillating gears 11, 12; and an output shaft 9 to which the rotational force of the oscillating gears 11, 12 is transmitted. Either of the shafts 8, 9 has, at least in part, a shaft side high thermal conductivity part extending over the entire axial direction of the shafts 8, 9 and having a thermal conductivity higher than those of the oscillating gears 11, 12.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gear 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, have a speed reduction mechanism as a gear mechanism at a joint where two arms are connected, and further have 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 may be, for example, an eccentric oscillating type reduction mechanism with high rotational position accuracy and load resistance. This type of reduction mechanism includes, for example, an internal gear, an oscillating gear (external gear) that meshes with the internal gear, and a crankshaft (eccentric body) that oscillates and rotates the oscillating gear. However, in this type of reduction mechanism, the temperature inside the reduction mechanism rises due to frictional heat generated by the sequential shifting of the meshing position between the internal gear and the oscillating gear. If the temperature inside the reduction mechanism becomes too high, seizure or other problems will occur, shortening the product life. For this reason, various technologies have been proposed to suppress the temperature rise inside the reduction mechanism.

[0004] For example, a technology has been disclosed in which an oscillating gear is made of resin. One technology has been disclosed in which the internal gear is constructed from a resin case (internal gear main body) and internal pins (external pins) that are rotatably disposed in pin grooves provided in the case and are made of a material with a higher thermal conductivity than that of the case. This configuration aims to transfer heat generated by meshing between the internal gear and the oscillating gear to the internal pins, thereby suppressing temperature increases in the case and the oscillating gear. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2020-16262 Summary of the Invention [Problem to be solved by the invention]

[0006] In the internal gear of the gear mechanism described above, the volume of the internal pin is extremely small compared to the volume of the case. This limits the amount of heat that can be stored in the internal pin, so suppressing temperature rise within the gear mechanism actually depends on the heat dissipation ability of the case. As a result, heat dissipation within the gear mechanism is not promoted and heat is trapped, making it difficult to efficiently suppress temperature rise within the gear mechanism.

[0007] The present invention provides a gear mechanism and a robot that can efficiently suppress an increase in internal temperature. [Means for solving the problem]

[0008] A gear mechanism according to one embodiment of the present invention comprises a first gear, a second gear meshed with the first gear, and a shaft inserted into the second gear to transmit rotational force to the second gear or to which rotational force of the second gear is transmitted, wherein the shaft has a shaft-side high thermal conductivity portion having a thermal conductivity higher than that of the second gear over at least a portion of the entire axial direction of the shaft.

[0009] With this configuration, heat generated by the meshing of the first gear and the second gear and heat generated between the second gear and the shaft can be actively transferred to the shaft. Because a shaft-side high thermal conductivity portion is provided over the entire axial direction of at least a portion of the shaft, the heat transferred to the shaft is distributed to both axial ends of the shaft. Heat can be actively dissipated from both axial ends of the shaft. This makes it possible to efficiently suppress temperature increases inside the gear mechanism.

[0010] In the above configuration, the shaft has a tubular portion extending throughout the entire axial direction of the shaft, and a shaft-side high thermal conductivity portion provided inside the tubular portion and in contact with the inner surface of the tubular portion, and the rigidity of the tubular portion may be higher than the rigidity of the shaft-side high thermal conductivity portion.

[0011] In the above configuration, the thermal conductivity of the shaft-side high thermal conductivity portion may be higher than the thermal conductivity of the tubular portion and may be 100 W / m·K or more.

[0012] In the above configuration, the shaft-side high thermal conductivity portion may be a heat pipe.

[0013] In the above configuration, a support part may be provided that rotatably supports the axial end part of the shaft, and the support part may have a support part-side high thermal conductivity part that is provided around the shaft and has a thermal conductivity higher than that of the second gear and the support part.

[0014] In the above configuration, the support portion may have a recess formed around the shaft, and the support portion side high thermal conductivity portion may be housed in the recess.

[0015] In the above configuration, the support-portion-side high thermal conductivity portion may be grease.

[0016] In the above configuration, the support portion-side high thermal conductivity portion may have a thermal conductivity of 5 W / m·K or more.

[0017] In the above configuration, the support portion may have a mating member to which the support portion is attached, and the mating member may have a thermal conductivity equal to or higher than the thermal conductivity of the shaft-side high thermal conductivity portion.

[0018] In the above configuration, the first gear is an internal gear having internal teeth, the second gear is an oscillating gear having external teeth that mesh with the internal teeth of the internal gear and that rotates in an oscillating manner, and the shaft may be at least one of an input crankshaft that has an eccentric portion that rotatably supports the oscillating gear and transmits rotational force to the oscillating gear, and an output shaft that is arranged around the input crankshaft and inserted into the oscillating gear to transmit the rotational force of the oscillating gear.

[0019] 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 and the thermal conductivity of the oscillating gear.

[0020] 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 that of the oscillating gear, and the thermal conductivity of the internal pins may be higher than that of the oscillating gear.

[0021] In the above configuration, the oscillating gear may be made of resin.

[0022] A gear mechanism according to another aspect of the present invention includes: an internal gear having internal teeth; an oscillating gear having external teeth meshing with the internal teeth of the internal gear and oscillatingly rotated; an input crankshaft having an eccentric portion rotatably supporting the oscillating gear and transmitting a rotational force to the oscillating gear; an output shaft disposed around the input crankshaft and inserted into the oscillating gear to which the rotational force of the oscillating gear is transmitted; and support portions rotatably supporting both axial end portions of the output shaft; and at least one of the output shafts has a tubular portion extending entirely in the axial direction, and a shaft-side high thermal conductivity portion provided inside the tubular portion and in contact with the inner surface of the tubular portion, the thermal conductivity of the shaft-side high thermal conductivity portion being higher than the thermal conductivity of the oscillating gear, the rigidity of the tubular portion being higher than the rigidity of the shaft-side high thermal conductivity portion, the support portion having a recess formed around the output shaft of the support portion, and the recess housing a support portion-side high thermal conductivity portion having a thermal conductivity higher than that of the oscillating gear.

[0023] In this way, with an eccentric oscillating gear mechanism, heat generated by meshing between the internal gear and the oscillating gear and heat generated between the oscillating gear and the shaft can be actively transferred to the input crankshaft or the output shaft. Since a shaft-side high thermal conductivity portion is provided over the entire axial length of at least one of the shafts, heat transferred to the input crankshaft or the output shaft is distributed to both axial ends of the shaft. Heat can be actively dissipated from both axial ends of either shaft. This makes it possible to efficiently suppress temperature increases inside the gear mechanism. Furthermore, by configuring at least one of the input crankshaft and the output shaft with a tubular portion and a high thermal conductivity shaft portion, the rigidity of the shaft can be ensured even if a high thermal conductivity shaft portion is used for either shaft, thereby providing a highly reliable gear mechanism.

[0024] A gear mechanism according to another aspect of the present invention comprises a cylindrical case, a plurality of internally toothed pins arranged circumferentially on the inner surface of the case, an oscillating gear having external teeth that mesh with the internally toothed pins and that rotates in an oscillating manner, 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 that is arranged around the input crankshaft and inserted into the oscillating gear and to which the rotational force of the oscillating gear is transmitted, and support portions that rotatably support both axial ends of the output shaft, wherein the thermal conductivity of the case is higher than the thermal conductivity of the internally toothed pins and the thermal conductivity of the oscillating gear.

[0025] In this way, with an eccentric oscillating gear mechanism, heat generated by meshing between the internal gear and the oscillating gear and heat generated between the oscillating gear and the shaft can be actively transferred to the case. Because heat can be efficiently dissipated through this case, temperature increases inside the gear mechanism can be efficiently suppressed.

[0026] Another aspect of the present invention provides a robot comprising a first member and a second member, and a gear mechanism provided between the first member and the second member and rotating the second member relative to the first member, the gear mechanism comprising an internal gear fixed to the first member and having internal teeth, an oscillating gear having external teeth meshing with the internal teeth of the internal gear and rotated in an oscillating manner, an input crankshaft having an eccentric portion rotatably supporting the oscillating gear and transmitting rotational force to the oscillating gear, an output shaft arranged around the input crankshaft and inserted into the oscillating gear to which the rotational force of the oscillating gear is transmitted, and support portions rotatably supporting both axial ends of the output shaft and fixed to the second member, and at least one of the input crankshaft and the output shaft has a shaft-side high thermal conductivity portion provided over at least the entire axial direction and having a thermal conductivity higher than that of the oscillating gear.

[0027] In this way, in a robot using an eccentric oscillating gear mechanism, temperature rise inside the gear mechanism can be efficiently suppressed, which results in extending the product life of the gear mechanism and reducing the maintenance costs of the robot.

[0028] In the above configuration, at least one of the input crankshaft and the output shaft may have a tubular portion extending entirely in the axial direction, and a shaft-side high thermal conductivity portion provided inside the tubular portion and in contact with the inner surface of the tubular portion.

[0029] In the above configuration, the support portion may have a recess formed around the output shaft of the support portion, and a support portion-side high thermal conductivity portion having a thermal conductivity higher than that of the oscillating gear may be housed in the recess.

[0030] In the aforementioned configuration, the thermal conductivity of the second member may be equal to or greater than the thermal conductivity of the output shaft. [Effects of the Invention]

[0031] The gear mechanism and robot described above can efficiently suppress an increase in internal temperature. [Brief explanation of the drawings]

[0032] [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

[0033] Next, an embodiment of the present invention will be described with reference to the drawings.

[0034] <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.

[0035] As shown in FIG. 1, the collaborative robot 100 includes a base unit 101 (an example of the first or second member in the claims) placed on an installation surface F, a rotating head 102 (an example of the first or second member in the claims) provided on the base unit 101, an arm unit 103 (an example of the first or second member in the claims) rotatably attached to the upper part of the rotating head 102 (an example of the first or second member in the claims) (both are also examples of the mating member in the claims), and the base unit 10 1, a rotary head 102, and 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 an 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.

[0036] 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 rotary head 102 via the first reduction gear mechanism 1. As a result, the rotary head 102 is driven to rotate around the first rotation axis L1 relative to the base part 101.

[0037] 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.

[0038] 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.

[0039] 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.

[0040] 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.

[0041] 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].

[0042] [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.

[0043] 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 2 (an example of a first gear or an internal gear in the claims), a carrier 7 (an example of a support portion in the claims) rotatably supported by the case 2, an input crankshaft 8 (a center shaft; an example of a shaft-side high thermal conductivity portion in the claims) rotatably supported by the carrier 7, a plurality of (e.g., three) output shafts 9 (an example of a shaft-side high thermal conductivity portion in the claims), and oscillating gears 11 and 12 (a first oscillating gear 11 and a second oscillating gear 12; an example of a second gear in the claims) rotatably supported by the input crankshaft 8.

[0044] 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.

[0045] 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 on the outer peripheral surface 2a of the case 2, closer to one side of the axial center (toward the left in Figure 2). The outer flange portion 4 has a rectangular cross section along the axial direction.

[0046] 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.

[0047] 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.

[0048] Furthermore, a plurality of internally toothed pins (an example of the first gear or 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 can be made of a metal material, a highly thermally conductive resin, a non-metallic material, or the like. The internally toothed pins 6 may also be made of a resin containing carbon nanotubes (CNTs) or boron nitride nanotubes (BNNTs). Furthermore, the internally toothed pins 6 may be made of an iron-based metal such as bearing steel. The internally toothed pins 6 may also be made of carbon fiber reinforced plastic (CFRP).

[0049] 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.

[0050] 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.

[0051] 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.

[0052] 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). Alternatively, 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 approximately 0.2 [W / m·K]. The thermal conductivity of PPS containing boron nitride is, for example, approximately 2.6 [W / m·K].

[0053] 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.

[0054] Furthermore, a plurality of (for example, three) output shaft holes 13b, 14b are formed around the input shaft holes 13a, 14a at equal intervals in the circumferential direction in each carrier 13, 14. The output shaft 9 is inserted into these output shaft holes 13b, 14b. 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.

[0055] The recess 16 is filled with grease 17 (an example of the support portion-side high thermal conductivity portion in the claims). The grease 17 is a support portion-side high thermal conductivity portion having a thermal conductivity higher than that of the oscillating gears 11, 12 and the second carrier 14. The thermal conductivity of the grease 17 is 5 W / m K or higher. The output shaft 9 inserted into the output shaft holes 13b and 14b is made of, for example, an aluminum alloy. That is, the output shaft 9 itself is made of a shaft-side high thermal conductivity portion having a thermal conductivity higher than that of the oscillating gears 11 and 12.

[0056] 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, the output shaft 9 can be made of, for example, an iron-based metal. Depending on the desired characteristics, carbon steel, bearing steel, or the like can be used as the iron-based metal. For example, the thermal conductivity of S45C iron is approximately 45 W / m K.

[0057] 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. A second end 9b of the output shaft 9 on the second carrier 14 side is located slightly lower than a 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. The recess 16 is formed in the second carrier 14 around the output shaft 9.

[0058] A retaining ring 18 is attached to each end 9a, 9b of the output shaft 9. The retaining ring 18 restricts axial movement of the output shaft 9 relative to each carrier 13, 14. In other words, the retaining ring 18 restricts each carrier 13, 14 from coming off the output shaft 9 in the axial direction. This keeps each carrier 13, 14 fitted into the corresponding expanded diameter portion 3a, 3b of the case 2. Furthermore, each carrier 13, 14 and each output shaft 9 are integrated. Furthermore, since the output shaft 9 is inserted into the output shaft hole 13b, 14b of each carrier 13, 14, it is arranged around the input crankshaft 8.

[0059] The input crankshaft 8 is made of, for example, an aluminum alloy, similar to the output shaft 9. That is, the input crankshaft 8 itself is made of a shaft-side high thermal conductivity portion having a thermal conductivity higher than that of the oscillating gears 11 and 12. In addition, the input crankshaft 8 can be made of, for example, stainless steel or various iron-based metals, just like the output shaft 9 .

[0060] 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.

[0061] 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.

[0062] 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°.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] External teeth 23a, 23b that mesh with the internally toothed pins 6 provided on the case 2 are formed on the outer peripheries of the two carriers 13, 14. The number of teeth of each of the external teeth 23a, 23b is, for example, one less than the number of the internally toothed 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) 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 when the output shaft 9 is inserted into the output shaft insertion holes 25a, 25b.

[0067] 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.

[0068] <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.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] 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.

[0073] 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, stainless steel. 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.

[0074] 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.

[0075] 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 (see the arrows in FIG. 2). 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.

[0076] On the other hand, the heat transferred to the output shaft 9 is distributed throughout the entire axial direction and is transferred to the first end 9a and the second end 9b (see the arrows in FIG. 2), and is then dissipated through each of 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.

[0077] 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.

[0078] 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.

[0079] As described above, the reduction gears 1A, 1B, and 1C described above include the case 2 (internal pin 6), the oscillating gears 11 and 12 meshed with the internal pin 6, the input crankshaft 8 that transmits rotational force to the oscillating gears 11 and 12, and the output shaft 9 to which the rotational force of the oscillating gears 11 and 12 is transmitted. The shafts 8 and 9 are formed of, for example, an aluminum alloy, which has a higher thermal conductivity than the oscillating gears 11 and 12. This allows heat generated by the internal pin 6, the oscillating gears 11 and 12, the carriers 13 and 14, and the bearings 15a to 15d to be actively transmitted to the input crankshaft 8 and the output shaft 9. The heat transmitted to the shafts 8 and 9 is distributed throughout the entire axial direction and can be actively dissipated from the ends 8a to 9b of the shafts 8 and 9. This allows for efficient suppression of temperature rises within the reduction gears 1A, 1B, and 1C.

[0080] 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. Therefore, heat from the second end 9b of the output shaft 9 can be efficiently transferred to the rotary head 102 and the arms 111, 112 via the grease 17. Furthermore, heat from the second end 9b of the output shaft 9 can be efficiently dissipated with a simple structure.

[0081] If the recess 16 is not filled with the grease 17, the area where the recess 16 is formed becomes an air layer, which generates a heat insulating effect. By filling the recess 16 with the grease 17, the heat conduction efficiency in the recess 16 can be significantly improved. Since the thermal conductivity of the grease 17 is 5 W / m·K or more, heat can be efficiently transferred from the second end 9 b of the output shaft 9 to the second carrier 14, the rotating head 102, and each arm 111, 112, thereby dissipating the heat.

[0082] The base unit 101, the rotating head 102, the first arm 111, and the second arm 112 that constitute the collaborative robot 100 are made of, for example, an aluminum alloy. That is, the thermal conductivity of the base unit 101, the rotating head 102, the first arm 111, and the second arm 112 is equal to or higher than the thermal conductivity of each of the shafts 8 and 9, which are made of, for example, stainless steel. Therefore, heat transferred to each of the shafts 8 and 9 can be efficiently transferred to the rotating head 102, the first arm 111, and the second arm 112. This further improves the heat dissipation performance of the heat transferred to each of the shafts 8 and 9, and more efficiently suppresses temperature increases inside the reduction mechanisms 1A, 1B, and 1C.

[0083] As described above, in the eccentric oscillating type reduction mechanism (reduction mechanisms 1A, 1B, 1C), the heat generated by the internal pin 6, the oscillating gears 11, 12, the carriers 13, 14, and the bearings 15a to 15d can be efficiently dissipated by utilizing the input crankshaft 8 and the output shaft 9. The case 2 is made of, for example, an aluminum alloy. By making the thermal conductivity of the case 2 higher than that of the internal pin 6 and the oscillating gears 11 and 12, the case 2 can be used to actively dissipate heat inside the reduction mechanisms 1A, 1B, and 1C. The case 2 can maximize the heat dissipation area of ​​the reduction mechanisms 1A, 1B, and 1C. This makes it possible to more efficiently suppress temperature increases inside the reduction mechanisms 1A, 1B, and 1C.

[0084] The case 2 is formed from, for example, an aluminum alloy, and the internal pin 6 can be formed from a metal material, a highly thermally conductive resin, a non-metallic material, or the like. The oscillating gears 11 and 12 are formed from, 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.

[0085] Because the oscillating gears 11 and 12 are made of resin, the oscillating gears 11 and 12 can be easily molded, reducing the manufacturing costs of the reduction mechanisms 1A, 1B, and 1C. In addition, heat transfer to the oscillating gears 11 and 12 can be suppressed, thereby reducing unevenness in heat transfer to the case 2 and each of the shafts 8 and 9. This allows the heat inside the reduction mechanisms 1A, 1B, and 1C to be actively dissipated to the outside, making it possible to more efficiently suppress temperature increases inside the reduction mechanisms 1A, 1B, and 1C.

[0086] Furthermore, in the collaborative robot 100, by using the above-described reduction mechanisms 1A, 1B, and 1C, the temperature rise of the reduction mechanisms 1A, 1B, and 1C can be efficiently suppressed, thereby extending the product life of the reduction mechanisms 1A, 1B, and 1C, and thus reducing the maintenance cost of the collaborative robot 100.

[0087] In the first embodiment described above, the input crankshaft 8 and the output shaft 9 themselves are formed of an aluminum alloy or the like, which is a shaft-side high thermal conductive portion with a thermal conductivity higher than that of the oscillating gears 11 and 12. However, this is not limited thereto, and the input crankshaft 8 and the output shaft 9 may have at least a portion of a shaft-side high thermal conductive portion (e.g., an aluminum alloy) over the entire axial direction. For example, an aluminum alloy may be insert-molded into a portion of a resin shaft. By disposing the aluminum alloy over the entire axial direction, heat is distributed to both axial end portions 8a-9b of each shaft 8 and 9, and can be dissipated via each end portion 9a and 9b.

[0088] Furthermore, the input crankshaft 8 and the output shaft 9 do not all need to have the same configuration. At least one of the input crankshaft 8 and the output shaft 9 may have a shaft-side high thermal conductivity portion (e.g., aluminum alloy) at least in part over the entire axial direction.

[0089] [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.

[0090] 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 comprises a case 2, a carrier 7, an input crankshaft (an example of the shaft-side high thermal conductivity portion in the claims) 208, an output shaft (an example of the shaft-side high thermal conductivity portion in the claims) 209, and oscillating gears 11 and 12.

[0091] The difference between the first and second embodiments described above is that the shafts 8 and 9 in the first embodiment are different from the shafts 208 and 209 in the second embodiment. That is, the output shaft 209 includes an output tubular portion 31 extending in the axial direction, and an output heat pipe 32 provided inside the output tubular portion 31 .

[0092] The axial length of the output tubular portion 31 is the same as the axial length of the output shaft 9 of the above-described first embodiment. The output tubular portion 31 is cylindrical in its entirety in the axial direction. The output tubular portion 31 is formed, for example, from an aluminum alloy, similar to the output shaft 9 of the above-described first embodiment. Alternatively, the output tubular portion 31 can be made of, for example, stainless steel or various iron-based metals, similar to the output shaft 9. Retaining rings 18 are attached to both axial ends 209a, 209b of the output tubular portion 31.

[0093] The output heat pipe 32 is provided so as to fill the output tubular portion 31 and is in contact with the inner circumferential surface of the output tubular portion 31. The thermal conductivity of the output heat pipe 32 is approximately 30,000 [W / m K]. Since the output tubular portion 31 is made of an aluminum alloy, stainless steel, or an iron-based metal, the rigidity of the output tubular portion 31 is higher than the rigidity of the output heat pipe 32.

[0094] The input crankshaft 208 includes an input tubular portion 34 extending in the axial direction, and an input heat pipe 35 provided inside the input tubular portion 34. The axial length of the input tubular portion 34 is the same as the axial length of the input crankshaft 8 of the first embodiment described above. The input tubular portion 34 is cylindrical in its entirety in the axial direction. The input tubular portion 34 is formed of, for example, an aluminum alloy, similar to the input crankshaft 8 of the first embodiment described above. Alternatively, the input tubular portion 34 can be made of, for example, stainless steel or various iron-based metals, similar to the input crankshaft 8.

[0095] The input tubular portion 34 has a first eccentric portion 21a and a second eccentric portion 21b formed side by side in the axial direction between the bearings 15a and 15b provided on the carriers 13 and 14. The input tubular portion 34 also has an expanded diameter portion 20 formed 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. The input heat pipe 35 is disposed so as to fill the input tubular portion 34 and is in contact with the inner circumferential surface of the input tubular portion 34. The configuration of the input heat pipe 35 is the same as the configuration of the output heat pipe 32. Therefore, the rigidity of the input tubular portion 34 is higher than the rigidity of the input heat pipe 35.

[0096] Therefore, the second embodiment described above achieves the same effects as the first embodiment. Furthermore, each shaft 208, 209 includes a tubular portion 31, 34 (output tubular portion 31, input tubular portion 34) and a heat pipe 32, 35 (output heat pipe 32, input heat pipe 35) provided inside the tubular portion 31, 34. The rigidity of the tubular portion 31, 34 is higher than the rigidity of the heat pipe 32, 35. Therefore, by using a material with high thermal conductivity such as the heat pipe 32, 35, the thermal conductivity of the entire shaft 208, 209 can be increased while ensuring the rigidity of the shaft 208, 209. As a result, a highly reliable reduction gear mechanism 201 can be provided. By using the heat pipes 32, 35, the thermal conductivity of the entire shaft 208, 209 can be effectively increased with a simple structure.

[0097] The thermal conductivity of the heat pipes 32, 35 is higher than that of the tubular portions 31, 34, and is 100 W / m K or higher. This allows the heat transferred to each of the shafts 208, 209 to be reliably and efficiently distributed to both axial end portions 208a to 209b (see arrows in FIG. 3). The heat transferred from these end portions 208a to 209b to each of the shafts 208, 209 can be actively dissipated. This allows the temperature rise inside the reduction gear mechanism 201 to be efficiently suppressed.

[0098] In the second embodiment described above, the heat pipes 32, 35 provided inside the tubular portions 31, 34 are used as the shaft-side highly thermally conductive portions having a thermal conductivity higher than that of the oscillating gears 11, 12. However, this is not limiting, and the shaft-side highly thermally conductive portions may have a thermal conductivity higher than that of the oscillating gears 11, 12. Preferably, the thermal conductivity is higher than that of the tubular portions 31, 34 and is 100 W / m K or higher.

[0099] For example, copper, silver, or thermal grease can be used instead of the heat pipes 32 and 35. The thermal conductivity of copper is about 403 [W / m·K]. The thermal conductivity of silver is about 428 [W / m·K]. With this configuration, the heat transferred to each of the shafts 208, 209 can be reliably and efficiently distributed to both axial ends 208a to 209b of each of the shafts 208, 209. The heat transferred to each of the shafts 208, 209 can be actively dissipated from each of the ends 208a to 209b. As a result, the temperature rise inside the reduction gear mechanism 201 can be efficiently suppressed.

[0100] In the second embodiment described above, the tubular portions 31, 32 constituting the respective shafts 208, 209 are described as being cylindrical in the entire axial direction. That is, the tubular portions 31, 32 are described as having holes (cavities) formed therethrough in the axial direction. However, this is not limited thereto, and the tubular portions 31, 32 do not necessarily need to have holes (cavities) formed over the entire axial direction.

[0101] A specific example of this is shown below the central axis C1 in FIG. That is, the output tubular portion 31 of the output shaft 210 shown in FIG. 3 below the central axis C1 may have a recess 33a formed in the axial center of the solid shaft 33 from the second end 209b to just before the first end 209a. This recess 33a can be filled with thermal grease or the like. A similar configuration can also be adopted for the input crankshaft 208. When such a configuration is adopted, the thermal conductivity of the tubular portions 31 and 32 is configured to be higher than that of the oscillating gears 11 and 12. This configuration achieves the same effects as the first embodiment described above. In addition, heat can be efficiently transferred to both axial ends 208a to 209b of each shaft 208, 209, and 210.

[0102] In the reduction mechanism 201, the output shafts 209 and 210 may be used in combination. In the second embodiment described above, the input crankshaft 208 and the output shaft 209 are configured from the tubular portions 31, 34 and the heat pipes 32, 35. However, this is not limiting, and it is sufficient that at least one of the input crankshaft 208 and the output shaft 209 is configured from the tubular portions 31, 34 and the heat pipes 32, 35.

[0103] 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.

[0104] 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.

[0105] 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.

[0106] 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.

[0107] In the above embodiment, the recess 16 formed in the second carrier 14 is filled with grease 17 as a support-side high thermal conductivity portion having a thermal conductivity higher than that of the oscillating gears 11 and 12 and the second carrier 14. However, this is not limited to this, and a member serving as a support-side high thermal conductivity portion does not necessarily have to be housed in the recess 16. When a support-side high thermal conductivity portion is provided in the second carrier 14, it does not have to be constituted by the recess 16 or grease 17. It is sufficient that a member serving as a support-side high thermal conductivity portion having a thermal conductivity higher than that of the oscillating gears 11 and 12 and the second carrier 14 is provided in a location on the second carrier 14 corresponding to the periphery of the output shaft 9. The support-side high thermal conductivity portion desirably has a thermal conductivity of 5 W / m K or higher.

[0108] In the above-described first embodiment, the reduction gear mechanisms 1A to 1C are described as including the input crankshaft 8 and the output shaft 9. In the above-described second embodiment, the reduction gear mechanism 201 is described as including the input crankshaft 208 and the output shaft 209. However, this is not limited to this, and the shafts 8 and 9 of the first embodiment and the shafts 208, 209, and 210 of the second embodiment may be used in combination.

[0109] 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]

[0110] 1A, 1B, 1C, 201... Reduction mechanism (gear mechanism) 2...Case (first gear, internal gear) 6...Internal pin (first gear, internal gear) 7...Carrier (support part) 8...Input crankshaft (shaft, high heat conductivity part on the shaft side) 9...Output shaft (shaft, high thermal conductivity part on shaft side) 11...First oscillating gear (second gear, oscillating gear) 12... Second oscillating gear (second gear, oscillating gear) 13...First carrier (support part) 14...Second carrier (support part) 16...Recess 17...Grease (high thermal conductivity part on the support side) 21a...First eccentric part (eccentric part) 21b...Second eccentric part (eccentric part) 23a, 23b…external teeth 31...Output tubular portion (tubular portion) 32...Output heat pipe (shaft side high thermal conductivity part, heat pipe) 33...Solid shaft (tubular part) 33a...recess (tubular portion) 34...Input tubular portion (tubular portion) 35...Input heat pipe (high thermal conductivity part on the shaft, heat pipe) 100... Collaborative robot (robot) 101...base portion (first member, second member, mating member) 102... Rotating head (first member, second member, mating member) 103...Arm unit (first member, second member, mating member) 111...First arm (first member, second member, mating member) 112... Second arm (first member, second member, mating member) 208...Input crankshaft (shaft) 209, 210...Output shaft (shaft)

Claims

1. A first gear; a second gear that meshes with the first gear; a shaft inserted into the second gear and configured to transmit a rotational force to the second gear or to which a rotational force of the second gear is transmitted; a support portion that rotatably supports an axial end portion of the shaft; Equipped with the shaft has a shaft-side high thermal conductivity portion having a thermal conductivity higher than that of the second gear over at least a portion of the shaft in the axial direction thereof, the support portion has a recess formed around the shaft for each of the shafts, the recesses are formed separately from one another without communicating with one another and are formed so as to expose an outer circumferential surface of the axial end of the shaft, A support portion-side high thermal conductivity portion having a thermal conductivity higher than that of the second gear and the support portion is housed in the recess in contact with the outer circumferential surface of the shaft. Gear mechanism.

2. The shaft a tubular portion extending over the entire axial length of the shaft; the shaft-side high thermal conductivity portion provided inside the tubular portion and in contact with an inner circumferential surface of the tubular portion; and 2. The gear mechanism according to claim 1, wherein the tubular portion has a rigidity higher than that of the shaft-side high thermal conductivity portion.

3. The thermal conductivity of the shaft-side high thermal conductivity portion is higher than the thermal conductivity of the tubular portion and is 100 W / m·K or more.

3. The gear mechanism according to claim 2.

4. The shaft-side high thermal conductivity portion is a heat pipe.

4. The gear mechanism according to claim 2 or 3.

5. The support-side high thermal conductivity portion is made of grease. The gear mechanism according to any one of claims 1 to 4.

6. 6. The gear mechanism according to claim 1, wherein the support-portion-side high-thermal-conductivity portion has a thermal conductivity of 5 W / m·K or more.

7. a mating member to which the support portion is attached, 7. The gear mechanism according to claim 1, wherein the thermal conductivity of the mating member is equal to or higher than the thermal conductivity of the shaft-side high thermal conductivity portion.

8. the first gear is an internal gear having internal teeth, the second gear is an oscillating gear that has external teeth that mesh with the internal teeth of the internal gear and is oscillatingly rotated, The shaft is at least one of an input crankshaft that has an eccentric portion that rotatably supports the oscillating gear and transmits rotational force to the oscillating gear, and an output shaft that is disposed around the input crankshaft and inserted into the oscillating gear to transmit the rotational force of the oscillating gear. A gear mechanism according to any one of claims 1 to 7.

9. 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 thermal conductivity of the case is higher than the thermal conductivity of the internal pin and the thermal conductivity of the oscillating gear.

9. The gear mechanism according to claim 8.

10. 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 thermal conductivity of the case is higher than the thermal conductivity of the oscillating gear; 9. The gear mechanism according to claim 8, wherein the thermal conductivity of the internally toothed pin is higher than the thermal conductivity of the oscillating gear.

11. The oscillating gear is made of resin. A gear mechanism according to any one of claims 8 to 10.

12. 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 disposed around the input crankshaft and inserted into the oscillating gear, to which a rotational force of the oscillating gear is transmitted; a support portion that rotatably supports both axial end portions of the output shaft, At least one of the input crankshaft and the output shaft is a tubular portion extending in the entire axial direction; a shaft-side high thermal conductivity portion provided inside the tubular portion and in contact with an inner circumferential surface of the tubular portion; and the thermal conductivity of the shaft-side high thermal conductivity portion is higher than the thermal conductivity of the oscillating gear, the rigidity of the tubular portion is higher than the rigidity of the shaft-side high thermal conductivity portion, the support portion has a recess formed around the output shaft for each of the output shafts of the support portion, the recesses are formed separately from one another without communicating with one another, and are formed so as to expose an outer circumferential surface of an axial end portion of the output shaft, The recessed portion accommodates a support portion-side high thermal conductivity portion having a thermal conductivity higher than that of the oscillating gear. Gear mechanism.

13. a first member and a second member; a gear mechanism provided between the first member and the second member, the gear mechanism rotating the second member relative to the first member; Equipped with The gear mechanism includes: an internal gear fixed to the first member and 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 disposed around the input crankshaft and inserted into the oscillating gear, to which a rotational force of the oscillating gear is transmitted; a support portion that rotatably supports both axial end portions of the output shaft and is fixed to the second member; Equipped with at least one of the input crankshaft and the output shaft has a shaft-side high thermal conductivity portion that is provided over at least a portion of the entire axial direction and has a thermal conductivity higher than that of the oscillating gear; the support portion has a recess formed around the output shaft for each of the output shafts, the recesses are formed separately from one another without communicating with one another, and are formed so as to expose an outer circumferential surface of an axial end portion of the output shaft, A support portion-side high thermal conductivity portion having a thermal conductivity higher than that of the oscillating gear and the support portion is housed in the recess in contact with the outer circumferential surface of the output shaft. robot.

14. At least one of the input crankshaft and the output shaft is a tubular portion extending in the entire axial direction; a shaft-side high thermal conductivity portion provided inside the tubular portion and in contact with the inner circumferential surface of the tubular portion; The robot of claim 13.

15. 15. The robot according to claim 13 or 14, wherein the thermal conductivity of the second member is equal to or greater than the thermal conductivity of the output shaft.

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