Gear mechanisms and robots

Abstract

This invention relates to gear mechanisms and robots. One embodiment of the reduction mechanism (1B) of the invention comprises: a housing (2) and an internal gear pin (6); oscillating gears (11, 12) meshing with the internal gear pin (6); an input crankshaft (8) transmitting rotational force to the oscillating gears (11), (12); and an output shaft (9) transmitting the rotational force of the oscillating gears (11), (12). Each of the shafts (8, 9) has a high thermal conductivity portion on its axial side, which at least partially extends along the axial direction of the shaft (8, 9) and has a thermal conductivity higher than that of the oscillating gears (11, 12).

Description

Technical Field

[0001] This invention relates to gear mechanisms and robots. Background Technology

[0002] Previously, collaborative robots, which share a workspace with operators, were known as robots. In such collaborative robots, for example, multi-joint collaborative robots, a reduction gear mechanism is installed at the joint connecting the two arms, and an electric motor is installed to apply rotational force to the reduction gear mechanism. By reducing and outputting the rotational force of the electric motor, a larger output torque can be applied from one arm to the other.

[0003] As a speed reduction mechanism, for example, an eccentric oscillating type speed reduction mechanism with high rotational positioning accuracy and load-bearing capacity is used. Such a speed reduction mechanism includes, for example, an internal gear, an oscillating gear (external gear) meshing with the internal gear, and a crankshaft (eccentric body) that causes the oscillating gear to oscillate and rotate.

[0004] However, in such a reduction mechanism, the temperature inside the mechanism rises due to frictional heat generated by the sequential changes in the meshing position between the internal gear and the oscillating gear. If the temperature inside the reduction mechanism becomes high, aging and other problems will occur, shortening the product's lifespan. Therefore, various techniques have been proposed to suppress the temperature rise inside the reduction mechanism.

[0005] For example, there are disclosed techniques for making the oscillating gear from resin. There is also a technique that discloses an internal gear consisting of a resin housing (internal gear body) and an internal pin (outer pin), the internal pin being rotatably disposed in a pin groove provided in the housing, and being formed from a raw material with a higher thermal conductivity than the housing. With this configuration, heat generated by the meshing between the internal gear and the oscillating gear is transferred to the internal pin, suppressing the temperature rise of the housing and the oscillating gear.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: Japanese Patent Application Publication No. 2020-16262 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] In the internal gear of the gear mechanism described above, the volume of the internal gear pin is extremely small compared to the volume of the housing. Therefore, the heat accumulated in the internal gear pin is limited, and the suppression of temperature rise within the gear mechanism actually depends on the heat dissipation of the housing. As a result, the following problem exists: heat retention occurs due to insufficient heat dissipation within the gear mechanism, making it difficult to efficiently suppress temperature rise within the gear mechanism.

[0011] This invention provides a gear mechanism and a robot that can efficiently suppress internal temperature rise.

[0012] Solution for solving the problem

[0013] A gear mechanism according to one embodiment of the present invention comprises: a first gear; a second gear meshing with the first gear; and a shaft inserted into the second gear, wherein the shaft transmits rotational force or the rotational force of the second gear along the axial direction of the second gear, the shaft having a high thermal conductivity portion on its axial side, the high thermal conductivity portion being integrally disposed on the shaft at least partially throughout the axial direction of the shaft, the thermal conductivity of the high thermal conductivity portion being higher than the thermal conductivity of the second gear.

[0014] This configuration allows for the efficient transfer of heat generated between the first and second gears, and between the second gear and the shaft, to the shaft. Because a high thermal conductivity section is integrally provided along the shaft's axial direction, at least partially, the heat transferred to the shaft is dispersed towards both axial ends. This enables efficient heat dissipation from both axial ends of the shaft. Therefore, it effectively suppresses temperature rise within the gear mechanism.

[0015] In the above structure, the shaft may also have a tubular portion that extends integrally along the axial direction of the shaft, the high thermal conductivity portion on the shaft side is disposed inside the tubular portion and contacts the inner circumferential surface of the tubular portion, and the rigidity of the tubular portion is higher than the rigidity of the high thermal conductivity portion on the shaft side.

[0016] In the above structure, the thermal conductivity of the axially high thermal conductivity part may be higher than that of the tubular part, and may be 100 W / m·K or more.

[0017] In the above structure, the axially high thermal conductivity part may also include a heat pipe.

[0018] In the above structure, the gear mechanism may also include a support portion that supports the axial end of the shaft in a rotatable manner. The support portion has a support-side high thermal conductivity portion disposed around the shaft, and the thermal conductivity of the support-side high thermal conductivity portion is higher than that of the second gear and the support portion.

[0019] In the above structure, the support portion may also have a recess formed around the shaft, and the thermally conductive portion of the support portion may be housed within the recess.

[0020] In the above structure, the high thermal conductivity part on the support side may also contain grease.

[0021] In the above structure, the thermal conductivity of the high thermal conductivity part on the support side may be 5 W / m·K or higher.

[0022] In the above structure, the gear mechanism may also have a corresponding component for mounting the support portion, and the thermal conductivity of the corresponding component is greater than or equal to the thermal conductivity of the high thermal conductivity portion on the shaft side.

[0023] In the above structure, the first gear may include an internal gear with internal teeth, the second gear may include an oscillating gear with external teeth that mesh with the internal teeth and oscillates, the shaft may include at least one of an input crankshaft that transmits rotational force to the oscillating gear and an output shaft that transmits rotational force to the oscillating gear, the input crankshaft having an eccentric portion that supports the oscillating gear for rotation, and the output shaft being disposed around the input crankshaft and inserted into the oscillating gear.

[0024] In the above structure, the internal gear may also include: a cylindrical outer shell; and a plurality of internal toothed pins arranged circumferentially on the inner circumferential surface of the outer shell, wherein the thermal conductivity of the outer shell is higher than that of the internal toothed pins and the thermal conductivity of the oscillating gear.

[0025] In the above structure, the internal gear may also include: a cylindrical outer shell; and a plurality of internal toothed pins arranged circumferentially on the inner circumferential surface of the outer shell, wherein the thermal conductivity of the outer shell is higher than that of the oscillating gear, and the thermal conductivity of the internal toothed pins is higher than that of the oscillating gear.

[0026] In the above structure, the oscillating gear may also be formed of resin.

[0027] Another technical solution of the present invention provides a robot comprising: a first component and a second component; and a gear mechanism disposed between the first component and the second component, the gear mechanism causing the second component to rotate relative to the first component, the gear mechanism comprising: an internal gear having internal teeth; a oscillating gear oscillating and rotating; an input crankshaft transmitting rotational force to the oscillating gear; an output shaft transmitting the rotational force of the oscillating gear; and a support fixed to the second component, the internal gear fixed to the first component, and the oscillating gear having internal teeth. The input crankshaft has external teeth that mesh with the internal teeth of the internal gear, and has an eccentric portion that supports the oscillating gear for rotation. The output shaft is disposed around the input crankshaft and inserted into the oscillating gear. The support portion supports both axial ends of the output shaft in a manner that allows the output shaft to rotate freely. At least one of the input crankshaft and the output shaft has a axially high thermal conductivity portion with a thermal conductivity higher than that of the oscillating gear. The axially high thermal conductivity portion is integrally disposed axially throughout at least a portion of the input crankshaft and the output shaft.

[0028] In robots employing eccentric oscillating gear mechanisms, the internal temperature rise of the gear mechanism can be effectively suppressed. This results in an extended product lifespan for the gear mechanism and reduced robot maintenance costs.

[0029] The effects of the invention

[0030] The aforementioned gear mechanism and robot can effectively suppress the rise in internal temperature. Attached Figure Description

[0031] Figure 1 This is a schematic structural diagram of a collaborative robot according to an embodiment of the present invention.

[0032] Figure 2 This is a schematic structural diagram of the second deceleration mechanism according to the first embodiment of the present invention.

[0033] Figure 3 This is a schematic structural diagram of the deceleration mechanism according to the second embodiment of the present invention.

[0034] Explanation of reference numerals in the attached figures

[0035] 1A, 1B, 1C, 201, Reduction mechanism (gear mechanism); 2, Housing (first gear, internal gear); 6, Internal pin (first gear, internal gear); 7, Gear carrier (support); 8, Input crankshaft (shaft, high thermal conductivity part on 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 gear carrier (support); 14, Second gear carrier (support); 16, Recess; 17, Grease (high thermal conductivity part on support side); 21a, First eccentric part (eccentric part); 21b, Second eccentric part (eccentric part); 23a, 23b, External gear; 31, Output tubular part ( 32. Output heat pipe (axially high thermal conductivity part, heat pipe); 33. Solid shaft (tubular part); 33a. Recess (tubular part); 34. Input tubular part (tubular part); 35. Input heat pipe (axially high thermal conductivity part, heat pipe); 100. Collaborative robot (robot); 101. Base part (first component, second component, corresponding component); 102. Rotating head (first component, second component, corresponding component); 103. Arm unit (first component, second component, corresponding component); 111. First arm (first component, second component, corresponding component); 112. Second arm (first component, second component, corresponding component); 208. Input crankshaft (shaft); 209, 210. Output shaft (shaft). Detailed Implementation

[0036] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[0037] Collaborative Robots

[0038] Figure 1 This is a schematic diagram of the collaborative robot 100.

[0039] 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 the setting surface F.

[0040] like Figure 1 As shown, the collaborative robot 100 includes: a base portion (an example of the first or second component in the claims) 101, which is mounted on a mounting surface F; a rotating head (an example of the first or second component in the claims) 102, which is disposed on the base portion 101; an arm unit (an example of the first or second component in the claims) 103 (both examples of corresponding components in the claims), which is rotatably assembled to the upper part of the rotating head (an example of the first or second component in the claims) 102; and reduction mechanisms 1A and 1B. B, 1C (first reduction mechanism 1A, second reduction mechanism 1B, third reduction mechanism 1C), which are assembled in the base part 101, the rotating head 102 and the joint parts 106a, 106b, 106c (first joint part 106a, second joint part 106b, third joint part 106c) of the arm unit 103; servo motors 107, 108, 109 (first servo motor 107, second servo motor 108, third servo motor 109), which serve as drive sources; and end effector 110, which is mounted in the arm unit 103.

[0041] The rotating head 102 is rotatably connected to the base portion 101 about the first rotation axis L1. The connection is at the first joint portion 106a, where the first reduction mechanism 1A and the first servo motor 107 are assembled.

[0042] The first rotation axis L1 is aligned with the vertical direction, for example. The rotation of the first servo motor 107 is transmitted to the rotary head 102 via the first reduction mechanism 1. As a result, the rotary head 102 is driven to rotate relative to the base portion 101 about the first rotation axis L1.

[0043] The arm unit 103 includes, for example, two arms 111 and 112 (first arm 111 and second arm 112) that are longer in one direction. One end of the first arm 111 is rotatably connected to the upper part of the rotating head 102 about the second rotation axis L2. The connection point is the second joint 106b, where the second reduction mechanism 1B and the second servo motor 108 are assembled.

[0044] The second rotation axis L2 is, for example, aligned with the horizontal direction. The rotation of the second servo motor 108 is transmitted to the first arm 111 via the second reduction mechanism 1B. As a result, the first arm 111 is driven to rotate relative to the rotating head 102 about the second rotation axis L2. For example, the first arm 111 is driven to swing relative to the base portion 101 in the back-and-forth direction.

[0045] One end of the second arm 112 of the two arms 111 and 112 is rotatably connected to the other end of the first arm 111 about the third rotation axis L3. The connection point is the third joint 106c, where the third reduction mechanism 1C and the third servo motor 109 are assembled.

[0046] The third rotation axis L3 is, for example, aligned with the horizontal direction. The rotation of the third servo motor 109 is transmitted to the second arm 112 via the third reduction mechanism 1C. As a result, the second arm 112 is driven to rotate relative to the first arm 111 about the third rotation axis L3. For example, the second arm 112 is driven to swing relative to the first arm 111 in the vertical direction.

[0047] The end effector 110 is mounted at the other end of the second arm 112. The end effector 110 is driven in three dimensions by driving the rotating head 102, the first arm 111, and the second arm 112.

[0048] The base 101, rotating head 102, first arm 111, and second arm 112 of the collaborative robot 100 are, for example, formed of aluminum alloy. The thermal conductivity of aluminum alloy is approximately 201 [W / m·K]. Alternatively, they can be formed of, for example, magnesium alloy, carbon fiber reinforced plastic (CFRP), or resin containing boron nitride to improve thermal conductivity. The thermal conductivity of magnesium alloy is, for example, approximately 51.2 [W / m·K].

[0049] [First Implementation]

[0050] <Speed ​​Reduction Mechanism>

[0051] Next, based on Figure 2 The deceleration mechanisms 1A to 1C are described below.

[0052] The basic structure of each reduction mechanism 1A to 1C is the same. Therefore, in the following description, only the second reduction mechanism 1B of each reduction mechanism 1A to 1C will be described, and the description of the first reduction mechanism 1A and the third reduction mechanism 1C will be omitted.

[0053] Figure 2 This is a schematic structural diagram of the second deceleration mechanism 1B.

[0054] like Figure 2As shown, the second reduction mechanism 1B is a so-called eccentric oscillating type reduction mechanism. The second reduction mechanism 1B includes a cylindrical housing (an example of the first gear or internal gear in the claims) 2, a gear carrier (an example of the support portion in the claims) 7 rotatably supported on the housing 2, an input crankshaft (central shaft; an example of the high thermal conductivity portion on the shaft side in the claims) 8 rotatably supported on the gear carrier 7, a plurality of (e.g., 3) output shafts (an example of the high thermal conductivity portion on the shaft side in the claims) 9, and oscillating gears 11 and 12 (the first oscillating gear 11 and the second oscillating gear 12; an example of the second gear in the claims) rotatably supported on the input crankshaft 8.

[0055] The central axis C1 of the outer casing 2 coincides with the second rotation axis L2. In the following description, the direction parallel to the second rotation axis L2 is sometimes referred to as the axial direction, the direction about the second rotation axis L2 is referred to as the circumferential direction, and the direction orthogonal to the axial and circumferential directions is referred to as the radial direction.

[0056] The outer casing 2 is formed, for example, of an aluminum alloy. Alternatively, the outer casing 2 may also be formed of a magnesium alloy, carbon fiber reinforced plastic (CFRP), or a resin containing boron nitride to improve thermal conductivity. It is desirable that the thermal conductivity of the outer casing 2 is higher than that of the internal toothed pin 6, which will be described later.

[0057] On the outer peripheral surface 2a of the outer casing 2, at a position closer to one side than the axial center (in) Figure 2 The outer flange 4, located on the left side of the center, is integrally formed and protrudes radially outward. The cross-section of the outer flange 4 along the axial direction is quadrilateral.

[0058] The outer flange 4 has a plurality of bolt holes 4a formed at equal intervals in the circumferential direction, extending axially. A rotating head 102 overlaps the outer flange 4, for example, from the outer axial direction. A bolt 5 is inserted into the bolt holes 4a from the side of the outer flange 4 opposite to the rotating head 102. By tightening the bolt 5 into the internal thread 102a of the rotating head 102, the housing 2 is fixed to the rotating head 102.

[0059] On the inner circumferential surface 2b of the outer casing 2, enlarged diameter portions 3a and 3b (first enlarged diameter portion 3a and second enlarged diameter portion 3b) are formed on both axial sides via stepped portions 3c and 3d (first stepped portion 3c and second stepped portion 3d). The inner diameter of each enlarged diameter portion 3a and 3b is larger than the inner diameter of the inner circumferential surface 2b of the outer casing 2. A gear carrier 7 is provided in each enlarged diameter portion 3a and 3b.

[0060] A plurality of internal toothed pins (an example of the first gear or internal gear in the claims) 6 are provided on the inner circumferential surface 2b of the outer casing 2 between two stepped portions 3c and 3d. The internal toothed pins 6 can be formed of metallic materials, highly thermally conductive resins, non-metallic materials, etc. The internal toothed pins 6 can also be resins mixed with carbon nanotubes (CNTs) and boron nitride nanotubes (BNNTs). The internal toothed pins 6 can also be formed of ferrous metals such as bearing steel. The internal toothed pins 6 can also be formed using carbon fiber reinforced plastic (CFRP).

[0061] The internal toothed pin 6 is formed in a cylindrical shape. However, it is not limited to this; the internal toothed pin 6 can also be a hollow component. The internal toothed pin 6 can also be a multi-layered component formed by wrapping a core material with a surface material. For example, one of the core material and the surface material of the internal toothed pin 6 can be an ferrous metal, and the other can be a copper-based or aluminum-based metal. In this case, a balance between mechanical and thermal properties can be achieved. As another example, one of the core material and the surface material of the internal toothed pin 6 can be made of metal, and the other can be made of resin. The internal toothed pin 6 can also be formed of sintered metal.

[0062] The axial direction of the internal toothed pin 6 is aligned with the central axis C1 of the housing 2. The internal toothed pins 6 are arranged at equal intervals in the circumferential direction. The internal toothed pins 6 function as internal teeth that mesh with the oscillating gears 11 and 12.

[0063] The gear carrier 7 includes a first gear carrier (shaft flange) 13 and a second gear carrier (retaining flange) 14. The first gear carrier 13 is disposed on the first expanded diameter portion 3a on the side of the rotating head 102 in the two expanded diameter portions 3a and 3b formed in the housing 2. The second gear carrier 14 is disposed on the second expanded diameter portion 3b on the side opposite to the first expanded diameter portion 3a in the axial direction.

[0064] Each gear carrier 13 and 14 is formed in the shape of a circular plate. The outer peripheral surface of each gear carrier 13 and 14 can be slidably fitted into the corresponding enlarged diameter portions 3a and 3b. Each gear carrier 13 and 14 is axially positioned by abutting against the corresponding stepped portions 3c and 3d.

[0065] Each gear carrier 13, 14 is formed of resin, for example. For example, each gear carrier 13, 14 can be formed of POM (polyacetal). Each gear carrier 13, 14 can also be formed of resins different from POM, such as PAEK (poly ether ether ketone) or PAEK (polyaryl ether ketone). As the resin, it can also be PPS (polyphenylene sulfide) or a resin mixed with PPS. Each gear carrier 13, 14 can also be formed using 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].

[0066] An axially extending input shaft hole 13a, 14a is formed at the radial center of each gear carrier 13, 14. The input crankshaft 8 is inserted into these input shaft holes 13a, 14a.

[0067] Bearings 15a and 15b (first bearing 15a and second bearing 15b) are provided in each input shaft hole 13a and 14a. Ball bearings are used, for example, as bearings 15a and 15b. The input crankshaft 8 is rotatably supported on each gear carrier 13 and 14 via these bearings 15a and 15b. The axis of rotation of the input crankshaft 8 coincides with the central axis C1 (second axis of rotation L2) of the housing 2.

[0068] Each gear carrier 13, 14 has multiple (e.g., 3) output shaft holes 13b, 14b formed at equal intervals along the circumference around the input shaft holes 13a, 14a. Output shafts 9 are inserted into these output shaft holes 13b, 14b.

[0069] On a surface 14c of the second gear carrier 14, opposite to the first gear carrier 13, a recess 16 is formed on the same axis as the output shaft hole 14b. The recess 16 has an opening on one surface 14c and communicates with the output shaft hole 14b.

[0070] The recess 16 is filled with grease (an example of a high thermal conductivity support portion in the claims) 17. The grease 17 is a high thermal conductivity support portion with a higher thermal conductivity than the oscillating gears 11, 12 and the second gear carrier 14. The thermal conductivity of the grease 17 is 5 [W / m·K] or higher.

[0071] The output shaft 9, which is inserted into the output shaft holes 13b and 14b, is made of aluminum alloy, for example. That is, the output shaft 9 itself is formed by a high thermal conductivity section on the shaft side, which has a higher thermal conductivity than the oscillating gears 11 and 12.

[0072] The output shaft 9 is not limited to aluminum alloy and can also be made of stainless steel. Stainless steel has a thermal conductivity of approximately 16.7 [W / m·K]. In addition, ferrous metals can be used as the output shaft 9, for example. As ferrous metals, carbon steel, bearing steel, etc., can be used depending on the desired properties. For example, as iron, S45C has a thermal conductivity of approximately 45 [W / m·K].

[0073] The first end 9a of the output shaft 9 on the side of the first gear carrier 13 protrudes slightly from a surface 13c on the side of the first gear carrier 13 opposite to the second gear carrier 14. The second end 9b of the output shaft 9 on the side of the second gear carrier 14 is located at a position slightly lower than a surface 14c of the second gear carrier 14. That is, the second end 9b of the output shaft 9 is housed within a recess 16 of the second gear carrier 14. The recess 16 is shaped to surround the output shaft 9 formed in the second gear carrier 14.

[0074] Retaining rings 18 are installed at each end 9a, 9b of the output shaft 9. The retaining rings 18 restrict the axial movement of the output shaft 9 relative to each gear carrier 13, 14. In other words, the retaining rings 18 restrict the gear carriers 13, 14 from disengaging axially from the output shaft 9. Thus, each gear carrier 13, 14 maintains a state of engagement with the corresponding expanded diameter portions 3a, 3b of the housing 2. Each gear carrier 13, 14 is integrated with each output shaft 9. The output shaft 9 is inserted into the output shaft holes 13b, 14b of each gear carrier 13, 14, thus being positioned around the input crankshaft 8.

[0075] The input crankshaft 8, like the output shaft 9, is made of aluminum alloy, for example. That is, the input crankshaft 8 itself is formed of a shaft-side high thermal conductivity section with a higher thermal conductivity than that of the oscillating gears 11 and 12.

[0076] In addition, the input crankshaft 8 can be made of stainless steel or various ferrous metals, just like the output shaft 9.

[0077] The first end 8a on the first gear carrier 13 side of the input crankshaft 8 protrudes axially outward via the first bearing 15a disposed on the first gear carrier 13. A second servo motor 108 is connected to this first end 8a. The rotation of the second servo motor 108 is transmitted to the input crankshaft 8.

[0078] The second end 8b on the side of the second gear carrier 14 of the input crankshaft 8 and the end face of the second bearing 15b on the side opposite to the first gear carrier 13 are located on approximately the same plane.

[0079] The input crankshaft 8 has a first eccentric portion 21a and a second eccentric portion 21b arranged axially between the bearings 15a and 15b disposed on each gear carrier 13 and 14. An enlarged diameter portion 20, larger than the diameter of these eccentric portions 21a and 21b, is formed between each eccentric portion 21a and 21b on the input crankshaft 8.

[0080] The first eccentric portion 21a is disposed on the side of the first gear carrier 13. The second eccentric portion 21b is disposed on the side of the second gear carrier 14. Each eccentric portion 21a and 21b is eccentric relative to the second rotation axis L2. The phase angles of each eccentric portion 21a and 21b are offset from each other. For example, the phase angles of each eccentric portion 21a and 21b are offset from each other by 180°.

[0081] Bearings 15c and 15d (the third bearing 15c and the fourth bearing 15d) are respectively provided in each eccentric portion 21a and 21b. These bearings 15c and 15d are also ball bearings, for example, used in the same manner as the first bearing 15a and the second bearing 15b. The axial spacing of the bearings 15c and 15d is limited by the contact between the axial end faces of these bearings 15c and 15d and the enlarged diameter portion 20. Through these bearings 15c and 15d, the oscillating gears 11 and 12 (the first oscillating gear 11 and the second oscillating gear 12) are rotatably supported in each eccentric portion 21a and 21b.

[0082] The two oscillating gears 11 and 12 are formed of resin, for example. For instance, the oscillating gears 11 and 12 can be formed of POM (polyacetal). In addition, various resins can be used as the oscillating gears 11 and 12, similar to the materials used to form the gear carriers 13 and 14 described above. Because the oscillating gears 11 and 12 are formed of resin, the thermal conductivity of the output shaft 9 and the input crankshaft 8 is higher than that of the oscillating gears 11 and 12. The thermal conductivity of the housing 2 is higher than that of the oscillating gears 11 and 12. The thermal conductivity of the internal gear pin 6 is higher than that of the oscillating gears 11 and 12.

[0083] Two oscillating gears 11 and 12 are configured to be spaced apart between two gear carriers 13 and 14. Crankshaft insertion holes 24a and 24b (first crankshaft insertion hole 24a and second crankshaft insertion hole 24b) are formed at the radial center of each oscillating gear 11 and 12, extending along the thickness direction and fitting into the outer peripheral surfaces of corresponding bearings 15c and 15d. Thus, the oscillating gears 11 and 12 are rotatably supported by their respective eccentric portions 21a and 21b via the bearings 15c and 15d. The oscillating gears 11 and 12 oscillate and rotate using the eccentric portions 21a and 21b.

[0084] External teeth 23a and 23b are formed on the outer periphery of the two gear carriers 13 and 14 to mesh with the internal toothed pins 6 provided on the housing 2. The number of teeth of each external tooth 23a and 23b is, for example, one less than the number of internal toothed pins 6.

[0085] Two oscillating gears 11 and 12 have output shaft insertion holes 25a and 25b (first output shaft insertion hole 25a and second output shaft insertion hole 25b) formed at positions corresponding to the output shaft 9 for insertion of the output shaft 9. The inner diameter of each output shaft insertion hole 25a and 25b is the size that allows the oscillating gears 11 and 12 to oscillate and rotate when the output shaft 9 is inserted into these output shaft insertion holes 25a and 25b.

[0086] In the second reduction mechanism 1B constructed in this way, a first arm 111 overlaps, for example, on a surface 14c of the second gear carrier 14 on the side opposite to the first gear carrier 13. The first arm 111 is fixed to the first gear carrier 13 by bolts (not shown).

[0087] A protrusion 111a is formed on the first arm 111 to engage with the input shaft hole 14a of the second gear carrier 14. This allows for the radial positioning of the first arm 111 relative to the second gear carrier 14. The protrusion 111a protrudes to a degree that it faces the second bearing 15b and the second end 8b of the input crankshaft 8 with a slight clearance.

[0088] <The Operation and Function of the Second Reduction Mechanism>

[0089] Next, the operation and function of the second deceleration mechanism 1B will be explained.

[0090] The crankshaft 8 is rotated by driving the second servo motor 108. As a result, the oscillating gears 11 and 12, which are rotatably supported on the eccentric portions 21a and 21b, oscillate and rotate. Then, a portion of the external teeth 23a and 23b of each oscillating gear 11 and 12 meshes with the internal toothed pin 6 of the housing 2.

[0091] At this time, the number of teeth on each of the external teeth 23a and 23b is, for example, one less than the number of internal tooth pins 6. Therefore, the oscillating gears 11 and 12 rotate in such a way that the meshing parts of each of the external teeth 23a and 23b relative to the internal tooth pins 6 (outer housing 2) are staggered in the circumferential direction. This rotation is decelerated relative to the rotation of the input crankshaft 8.

[0092] Output shafts 9 are inserted into the output shaft insertion holes 25a and 25b of the oscillating gears 11 and 12. Therefore, the rotation of the oscillating gears 11 and 12 transmits rotational force in the direction of their rotation to each output shaft 9. Each output shaft 9 is supported by its respective gear carrier 13 and 14 for free rotation. Therefore, the rotational force of the oscillating gears 11 and 12 is transmitted to each gear carrier 13 and 14.

[0093] The outer peripheral surfaces of each gear carrier 13, 14 can slidably fit into the corresponding expanded diameter portions 3a, 3b of the housing 2. Therefore, each gear carrier 13, 14 rotates relative to the housing 2. That is, the rotation of the second servo motor 108 is reduced and output to the gear carrier 7 (first gear carrier 13, second gear carrier 14).

[0094] The rotating head 102 is fixed to the housing 2. On the other hand, the first arm 111 is fixed to the second gear carrier 14 of each gear carrier 13, 14. Therefore, the first arm 111 rotates relative to the rotating head 102 about the second rotation axis L2.

[0095] For example, when the rotation of the first arm 111 (second gear carrier 14) is restricted, the rotation of the second servo motor 108 is reduced and output to the housing 2. In this case, the rotating head 102 rotates relative to the first arm 111 about the second rotation axis L2. That is, the reduction mechanisms 1A to 1C restrict the rotation of either the housing 2 or the gear carrier 7, thereby making the other the output relative to each of the servo motors 107 to 109. This operating principle is also the same in the first reduction mechanism 1A and the third reduction mechanism 1C.

[0096] However, due to the meshing between the internal toothed pin 6 and the oscillating gears 11 and 12, the sliding friction between the housing 2 and each gear carrier 13 and 14, the sliding friction between each gear carrier 13 and 14 and the output shaft 9, and the sliding friction of the bearings 15a to 15d, each component generates heat.

[0097] The input crankshaft 8 and output shaft 9 are made of stainless steel, for example. The thermal conductivity of the input crankshaft 8 and output shaft 9 is higher than that of the oscillating gears 11 and 12.

[0098] Therefore, the heat retained inside the second reduction gear 1B is actively transferred to the input crankshaft 8 and the output shaft 9. For example, the heat from each bearing 15a to 15d and the heat from the oscillating gears 11 and 12 are actively transferred to the input crankshaft 8. The heat retained in the oscillating gears 11 and 12 due to the heat transferred from the internal gear pin 6, the third bearing 15c, and the fourth bearing 15d to the oscillating gears 11 and 12, as well as the heat of the oscillating gears 11 and 12 themselves, is actively transferred to the output shaft 9.

[0099] The heat transferred to the input crankshaft 8 is distributed and transferred along the entire axial direction until it reaches the first end 8a and the second end 8b (see reference). Figure 2(The arrow indicates heat dissipation). Heat is dissipated via each end 8a, 8b. The second end 8b faces the protrusion 111a of the first arm 111 through a small gap, so 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 therefore has a thermal conductivity greater than that of the input crankshaft 8 and the output shaft 9. Therefore, heat transferred from the input crankshaft 8 to the first arm 111 is effectively dissipated.

[0100] The heat transferred to the output shaft 9 is distributed and transferred along the entire axis until it reaches the first end 9a and the second end 9b (see reference). Figure 2 (The arrows). Heat is dissipated through each end 9a, 9b.

[0101] A recess 16 is formed around the second end 9b of the output shaft 9 on the second gear carrier 14. Grease 17 is filled in the recess 16. The first arm 111 is positioned such that it overlaps with a surface 14c of the second gear carrier 14, thus sealing the opening of the grease-filled recess 16. Therefore, heat from the second end 9b of the output shaft 9 is efficiently transferred to the first arm 111 via the grease 17. Consequently, heat transferred from the output shaft 9 to the first arm 111 is effectively dissipated.

[0102] The outer casing 2 is formed, for example, of an aluminum alloy. The internal toothed pin 6 can be formed of a metallic material, a resin with high thermal conductivity, a non-metallic material, etc. The oscillating gears 11 and 12 are formed, for example, of resin. The thermal conductivity of the outer casing 2 is higher than that of the oscillating gears 11 and 12, and the thermal conductivity of the internal toothed pin 6 is higher than that of the oscillating gears 11 and 12. Therefore, the heat generated by the meshing between the internal toothed pin 6 and the oscillating gears 11 and 12 can be actively transferred to the outer casing 2 and the internal toothed pin 6. Thus, heat retention inside the second reduction mechanism 1B is suppressed.

[0103] Regarding the heat dissipation effect described above, the first reduction gear 1A and the third reduction gear 1C also function similarly. Heat trapped inside these first reduction gear 1A and third reduction gear 1C is dissipated through the input crankshaft 8 and output shaft 9. Heat is effectively dissipated by transferring heat to the rotary head 102, the second arm 112, etc., via the input crankshaft 8 and output shaft 9. The housing 2 and the internal gear pin 6 effectively prevent heat from remaining inside each reduction gear 1A and 1C.

[0104] As described above, the reduction mechanisms 1A, 1B, and 1C include a housing 2 (internal gear pin 6), oscillating gears 11 and 12 meshing with the internal gear pin 6, an input crankshaft 8 that transmits rotational force to the oscillating gears 11 and 12, and an output shaft 9 that transmits the rotational force to the oscillating gears 11 and 12. Each shaft 8 and 9 is formed of, for example, an aluminum alloy with a higher thermal conductivity than the oscillating gears 11 and 12. Therefore, the heat generated by the internal gear pin 6, the oscillating gears 11 and 12, the gear carriers 13 and 14, and the bearings 15a to 15d can be actively transmitted to the input crankshaft 8 and the output shaft 9. The heat transmitted to each shaft 8 and 9 can be distributed along the entire axial direction, and heat is actively dissipated from the ends 8a to 9b of each shaft 8 and 9. Therefore, the temperature rise inside the reduction mechanisms 1A, 1B, and 1C can be effectively suppressed.

[0105] A recess 16 is formed around the second end 9b of the output shaft 9 on the second gear carrier 14. Grease 17 is filled in the recess 16. Therefore, heat from the second end 9b of the output shaft 9 can be efficiently transferred to the rotating head 102 and the arms 111, 112 via the grease 17. This allows for efficient heat dissipation from the second end 9b of the output shaft 9 with a simple construction.

[0106] When the recess 16 is not filled with grease 17, the area where the recess 16 is formed becomes an air layer, thus producing a heat insulation effect. By filling the recess 16 with grease 17, the thermal conductivity of the recess 16 can be improved at each stage.

[0107] The grease 17 has a thermal conductivity of 5 [W / m·K] or higher, thus enabling efficient heat transfer and dissipation from the second end 9b of the output shaft 9 to the second gear carrier 14, the rotating head 102, and each arm 111, 112.

[0108] The base 101, rotating head 102, first arm 111, and second arm 112 constituting the collaborative robot 100 are, for example, made of aluminum alloy. That is, the thermal conductivity of the base 101, rotating head 102, first arm 111, and second arm 112 is, for example, higher than the thermal conductivity of each of the shafts 8 and 9, which are made of stainless steel. Therefore, heat transferred to each shaft 8 and 9 can be efficiently transferred to the rotating head 102, first arm 111, and second arm 112. Therefore, the heat dissipation of heat transferred to each shaft 8 and 9 can be further improved, and the temperature rise inside the deceleration mechanisms 1A, 1B, and 1C can be further effectively suppressed.

[0109] As described above, in the eccentric oscillating type reduction mechanism (reduction mechanism 1A, 1B, 1C), the input crankshaft 8 and output shaft 9 can be used to efficiently dissipate heat from the internal gear pin 6, oscillating gears 11, 12, each gear carrier 13, 14, and bearings 15a to 15d.

[0110] The outer casing 2 is made of, for example, aluminum alloy. By making the thermal conductivity of the outer casing 2 higher than that of the internal gear pin 6 and the oscillating gears 11 and 12, the outer casing 2 can actively dissipate heat from the interior of the reduction mechanisms 1A, 1B, and 1C. Using the outer casing 2, the heat dissipation area of ​​the reduction mechanisms 1A, 1B, and 1C can be maximized. Therefore, the temperature rise inside the reduction mechanisms 1A, 1B, and 1C can be suppressed more efficiently.

[0111] Besides the outer casing 2 being made of, for example, aluminum alloy, the internal gear pin 6 can also be made of metallic materials, highly thermally conductive resins, non-metallic materials, etc. The oscillating gears 11 and 12 are, for example, made of resin. The thermal conductivity of the outer casing 2 is higher than that of the oscillating gears 11 and 12, and the thermal conductivity of the internal gear pin 6 is higher than that of the oscillating gears 11 and 12. Therefore, the heat generated by the meshing between the internal gear pin 6 and the oscillating gears 11 and 12 can be actively transferred to the outer casing 2 and the internal gear pin 6. Therefore, heat retention inside the second reduction mechanism 1B can be suppressed.

[0112] The oscillating gears 11 and 12 are formed of resin, thus allowing for easy molding and reducing the manufacturing cost of the reduction mechanisms 1A, 1B, and 1C. Heat transfer to the oscillating gears 11 and 12 is suppressed, resulting in reduced uneven heat transfer to the housing 2 and the shafts 8 and 9. Therefore, heat inside the reduction mechanisms 1A, 1B, and 1C can be actively dissipated to the outside, more efficiently suppressing temperature rise inside the reduction mechanisms 1A, 1B, and 1C.

[0113] In the collaborative robot 100, by using the aforementioned reduction mechanisms 1A, 1B, and 1C, the temperature rise of the reduction mechanisms 1A, 1B, and 1C is effectively suppressed, thereby extending the product life of the reduction mechanisms 1A, 1B, and 1C. Therefore, the maintenance cost of the collaborative robot 100 can also be reduced.

[0114] In the first embodiment described above, the case where the input crankshaft 8 and output shaft 9 are themselves formed of a high thermal conductivity axial portion, i.e., aluminum alloy, which has a higher thermal conductivity than the oscillating gears 11 and 12, was described. However, this is not a limitation; it is sufficient that the input crankshaft 8 and output shaft 9 have a high thermal conductivity axial portion (e.g., aluminum alloy) at least partially throughout the axial direction. For example, molded aluminum alloy may be partially embedded in the resin shaft. By arranging aluminum alloy throughout the axial direction, heat can be distributed to both axial ends 8a to 9b of each shaft 8 and 9 and dissipated through each end 9a and 9b.

[0115] The input crankshaft 8 and the output shaft 9 do not need to be entirely identical. It is sufficient that at least either the input crankshaft 8 or the output shaft 9 has a high thermal conductivity section (e.g., aluminum alloy) on the shaft side, at least locally throughout the axial direction.

[0116] [Second Implementation]

[0117] <Speed ​​Reduction Mechanism>

[0118] Next, quote Figure 1 ,based on Figure 3 The second embodiment will be described.

[0119] Figure 3 This is a schematic structural diagram of the deceleration mechanism 201 according to the second embodiment. The same reference numerals are used to describe the same features as in the first embodiment. In the description of the second embodiment, sometimes the same names as in the first embodiment are used and descriptions are omitted.

[0120] like Figure 1 As shown, in the second embodiment, the use of the deceleration mechanism 201 in the collaborative robot 100 is the same as in the first embodiment described above.

[0121] like Figure 2 As shown, the reduction mechanism 201 of the second embodiment is a so-called eccentric oscillating type reduction mechanism, which is the same as the reduction mechanisms 1A, 1B, and 1C of the first embodiment described above in terms of having a housing 2, a gear carrier 7, an input crankshaft (an example of a shaft-side high thermal conductivity part in the claims) 208, an output shaft (an example of a shaft-side high thermal conductivity part in the claims) 209, and oscillating gears 11 and 12.

[0122] The difference between the first embodiment and the second embodiment mentioned above is as follows: the axes 8 and 9 in the first embodiment are different from the axes 208 and 209 in the second embodiment.

[0123] That is, the output shaft 209 has an output tubular portion 31 extending along the axial direction and an output heat pipe 32 disposed inside the output tubular portion 31.

[0124] The axial length of the output tubular portion 31 is the same as the axial length of the output shaft 9 in the first embodiment described above. The output tubular portion 31 is cylindrical in the axial direction. The output tubular portion 31 is formed of aluminum alloy, for example, in the same way as the output shaft 9 in the first embodiment described above. In addition, the output tubular portion 31 can be made of materials such as stainless steel or various ferrous metals, just like the output shaft 9. Retaining rings 18 are installed at both axial ends 209a and 209b of the output tubular portion 31.

[0125] The output heat pipe 32 is embedded inside the output tubular portion 31 and contacts 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 formed of aluminum alloy, stainless steel, or ferrous metals, the rigidity of the output tubular portion 31 is higher than that of the output heat pipe 32.

[0126] The input crankshaft 208 includes an axially extending input tubular portion 34 and an input heat pipe 35 disposed 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 in the first embodiment described above. The axial portion 34 is cylindrical in shape. The input tubular portion 34 is formed of aluminum alloy, for example, similar to the input crankshaft 8 in the first embodiment described above. In addition, the input tubular portion 34 can be made of materials such as stainless steel or various ferrous metals, similar to the input crankshaft 8.

[0127] In the input tubular section 34, a first eccentric portion 21a and a second eccentric portion 21b are formed between the bearings 15a and 15b disposed in each gear carrier 13 and 14 in an axially arranged manner. An enlarged diameter portion 20 with a larger diameter than the diameter of these eccentric portions 21a and 21b is formed between each eccentric portion 21a and 21b in the input tubular section 34.

[0128] The input heat pipe 35 is configured to be embedded within the input tubular portion 34 and in contact with the inner circumferential surface of the input tubular portion 34. The structure of the input heat pipe 35 is the same as that of the output heat pipe 32. Therefore, the rigidity of the input tubular portion 34 is higher than that of the input heat pipe 35.

[0129] Therefore, according to the second embodiment described above, the same effects as those of the first embodiment are achieved. Each shaft 208, 209 includes tubular portions 31, 34 (output tubular portion 31, input tubular portion 34) and heat pipes 32, 35 (output heat pipe 32, input heat pipe 35) disposed inside the tubular portions 31, 34. The rigidity of the tubular portions 31, 34 is higher than that of the heat pipes 32, 35. Therefore, materials with high thermal conductivity, such as heat pipes 32, 35, can be used to improve the overall thermal conductivity of each shaft 208, 209, while also ensuring the rigidity of each shaft 208, 209. As a result, a highly reliable deceleration mechanism 201 can be provided. By using heat pipes 32, 35, the overall thermal conductivity of each shaft 208, 209 can be effectively improved with a simple construction.

[0130] The heat pipes 32 and 35 have a higher thermal conductivity than the tubular sections 31 and 34, exceeding 100 [W / m·K]. Therefore, the heat transferred to each shaft 208 and 209 can be reliably and efficiently distributed to the two ends 208a to 209b of the axial direction (see reference). Figure 3 (The arrows indicate this). This allows heat transferred to each shaft 208, 209 to be actively dissipated from these ends 208a to 209b. Therefore, it is possible to efficiently suppress the temperature rise inside the reduction mechanism 201.

[0131] In the second embodiment described above, the case where heat pipes 32 and 35 disposed inside the tubular portions 31 and 34 are used as axially high thermal conductivity portions with a thermal conductivity higher than that of the oscillating gears 11 and 12 has been described. However, it is not limited to this, as long as the thermal conductivity of the axially high thermal conductivity portion is higher than that of the oscillating gears 11 and 12. It is desirable that the thermal conductivity is higher than that of the tubular portions 31 and 34, and the thermal conductivity is 100 [W / m·K] or higher.

[0132] For example, copper, silver, or thermal grease can be used to replace heat pipes 32 and 35. Copper has a thermal conductivity of approximately 403 W / m·K. Silver has a thermal conductivity of approximately 428 W / m·K.

[0133] This configuration allows heat transferred to each shaft 208, 209 to be reliably and efficiently distributed to both axial ends 208a-209b of each shaft 208, 209. It also allows heat transferred to each shaft 208, 209 to be actively dissipated from each end 208a-209b. Therefore, it effectively suppresses temperature rise inside the reduction mechanism 201.

[0134] In the second embodiment described above, the case where the tubular portions 31 and 32 constituting each shaft 208 and 209 are cylindrical in the axial direction was explained. That is, the case where the tubular portions 31 and 32 are formed with holes (cavities) extending through the axial direction was explained. However, it is not limited to this, and it is also possible that the holes (cavities) in the tubular portions 31 and 32 are not completely formed throughout the axial direction.

[0135] In response, Figure 3 A specific example is shown at a position lower than the central axis C1.

[0136] That is, it can also be, in Figure 3 The output tubular portion 31 of the output shaft 210, shown in the diagram below the central axis C1, has a recess 33a formed in the axial center of the solid shaft 33, near the front of the second end 209b to the first end 209a. This recess 33a can be filled with hot grease or similar material. The input crankshaft 208 can also adopt the same structure. With this structure, the thermal conductivity of the tubular portions 31 and 32 is higher than that of the oscillating gears 11 and 12. This configuration achieves the same effect as the first embodiment described above. Furthermore, heat can be efficiently transferred to the axial ends 208a to 209b of each shaft 208, 209, and 210.

[0137] In the reduction mechanism 201, the output shafts 209 and 210 can also be used in combination.

[0138] In the second embodiment described above, the case where the input crankshaft 208 and the output shaft 209 are composed of tubular portions 31 and 34 and heat pipes 32 and 35 has been explained. However, it is not limited to this, as long as at least one of the input crankshaft 208 and the output shaft 209 is composed of tubular portions 31 and 34 and heat pipes 32 and 35.

[0139] This invention is not limited to the embodiments described above, but includes embodiments that are modified from the above embodiments without departing from the spirit of this invention.

[0140] For example, in the above embodiment, the case of using the deceleration mechanisms 1A-1C and 201 as a collaborative robot 100 has been described. However, it is not limited to this. The structure of the above embodiment can be adopted in a variety of robots with the following structure: having two components (first component and second component), with the deceleration mechanisms 1A-1C and 201 provided between the two components, and the second component rotating relative to the first component.

[0141] In the above embodiments, reduction mechanisms 1A-1C and 201 were described as examples of gear mechanisms. However, gear mechanisms are not limited to this. The structure of the above embodiments can be adopted in a variety of gear mechanisms, such as those that replace reduction mechanisms 1A-1C to mesh two gears and transmit rotational force to one of the two gears, or those that have a shaft for transmitting rotational force to one of the gears.

[0142] In the above embodiment, the reduction mechanisms 1A-1C and 201 are described as so-called eccentric oscillating type reduction mechanisms, having a central crankshaft (input crankshaft 8, 208) coaxial with the central axis C1 of the housing 2. However, it is not limited to this; as an eccentric oscillating type reduction mechanism, it is also possible to have a structure in which the oscillating gears 11 and 12 oscillate and rotate by rotating multiple input crankshafts 8, 208 in conjunction. In this case, the input crankshafts 8, 208 themselves revolve around the central axis C1 while rotating on their own axis.

[0143] The case where the collaborative robot 100 described above uses servo motors 107, 108, and 109 as the drive source has been explained. However, it is not limited to this; various other drive sources, such as electric motors, hydraulic motors, and engines, can be used instead of servo motors as the drive source.

[0144] In the above embodiment, the case where the recess 16 formed in the second gear carrier 14 is filled with grease 17 to form a high thermal conductivity support section with a thermal conductivity higher than that of each oscillating gear 11, 12 and the second gear carrier 14 has been described. However, this is not a limitation, and the component serving as the high thermal conductivity support section may not be housed in the recess 16. When the high thermal conductivity support section is provided in the second gear carrier 14, it may not be composed of the recess 16 and grease 17. It is sufficient to provide a component serving as the high thermal conductivity support section with a thermal conductivity higher than that of each oscillating gear 11, 12 and the second gear carrier 14 at a position corresponding to the periphery of the output shaft 9 in the second gear carrier 14. As a high thermal conductivity support section, it is desirable that the thermal conductivity is 5 [W / m·K] or higher.

[0145] In the first embodiment described above, the reduction mechanisms 1A to 1C are described as having an input crankshaft 8 and an output shaft 9. In the second embodiment described above, the reduction mechanism 201 is described as having an input crankshaft 208 and an output shaft 209. However, it is not limited to this, and the shafts 8 and 9 of the first embodiment can also be used in combination with the shafts 208, 209, and 210 of the second embodiment.

[0146] In the embodiments disclosed in this specification, a component composed of multiple objects may be integrated into one unit; conversely, a component composed of a single object may be divided into multiple objects. Whether integrated or not, the configuration is sufficient to achieve the purpose of the invention.

[0147] The present invention includes the following forms.

[0148] (Postscript 1)

[0149] A gear mechanism, wherein,

[0150] This gear mechanism has the following features:

[0151] Internal gears, which have internal teeth;

[0152] A oscillating gear that oscillates and rotates.

[0153] The input crankshaft transmits rotational force to the oscillating gear;

[0154] An output shaft that transmits the rotational force of the oscillating gear; and

[0155] A support portion that rotatably supports both axial ends of the output shaft.

[0156] The oscillating gear has external teeth that mesh with the internal teeth of the internal gear.

[0157] The input crankshaft has an eccentric portion that supports the oscillating gear for free rotation.

[0158] The output shaft is positioned around the input crankshaft and inserted into the oscillating gear.

[0159] At least one of the input crankshaft and the output shaft has:

[0160] A tubular portion that extends integrally along the axial direction; and

[0161] A high thermal conductivity axial section is disposed inside the tubular section.

[0162] The axially high thermal conductivity section is in contact with the inner circumferential surface of the tubular section.

[0163] The thermal conductivity of the high thermal conductivity section on the shaft side is higher than that of the oscillating gear.

[0164] The rigidity of the tubular section is higher than that of the axial side, which is also higher than that of the thermally conductive section.

[0165] The support portion has a recess formed around the output shaft.

[0166] The recess houses a support-side high thermal conductivity part, which has a higher thermal conductivity than the oscillating gear.

[0167] (Postscript 2)

[0168] A gear mechanism, wherein,

[0169] This gear mechanism has the following features:

[0170] A cylindrical shell;

[0171] Multiple internal toothed pins are arranged circumferentially on the inner circumferential surface of the housing;

[0172] A oscillating gear that oscillates and rotates.

[0173] The input crankshaft transmits rotational force to the oscillating gear;

[0174] An output shaft that transmits the rotational force of the oscillating gear; and

[0175] A support portion that rotatably supports both axial ends of the output shaft.

[0176] The oscillating gear has external teeth that mesh with the internal toothed pin.

[0177] The input crankshaft has an eccentric portion that supports the oscillating gear for free rotation.

[0178] The output shaft is positioned around the input crankshaft and inserted into the oscillating gear.

[0179] The thermal conductivity of the outer casing is higher than that of the internal toothed pin and the oscillating gear.

[0180] (Note 3)

[0181] A robot, in which,

[0182] This robot has the following features:

[0183] Component 1 and Component 2; and

[0184] A gear mechanism is disposed between the first component and the second component.

[0185] The gear mechanism causes the second component to rotate relative to the first component.

[0186] The gear mechanism includes:

[0187] Internal gears, which have internal teeth;

[0188] A oscillating gear that oscillates and rotates.

[0189] The input crankshaft transmits rotational force to the oscillating gear;

[0190] An output shaft that transmits the rotational force of the oscillating gear; and

[0191] The support portion, which is fixed to the second component,

[0192] The internal gear is fixed to the first component.

[0193] The oscillating gear has external teeth that mesh with the internal teeth of the internal gear.

[0194] The input crankshaft has an eccentric portion that supports the oscillating gear for free rotation.

[0195] The output shaft is positioned around the input crankshaft and inserted into the oscillating gear.

[0196] The support portion supports both axial ends of the output shaft in a manner that allows the output shaft to rotate freely.

[0197] At least one of the input crankshaft and the output shaft has a shaft-side high thermal conductivity section with a higher thermal conductivity than the oscillating gear.

[0198] The high thermal conductivity axial section is integrally and axially distributed at least partially throughout the input crankshaft and the output shaft.

[0199] At least one of the input crankshaft and the output shaft has:

[0200] A tubular portion that extends integrally along the axial direction; and

[0201] A high thermal conductivity axial section is disposed inside the tubular section.

[0202] The axially high thermal conductivity section is in contact with the inner circumferential surface of the tubular section.

[0203] (Postscript 4)

[0204] According to the robot described in Appendix 3, wherein...

[0205] The support portion has a recess formed around the output shaft, and a high thermal conductivity portion on the support portion side is received in the recess.

[0206] The thermal conductivity of the high thermal conductivity part on the support side is higher than that of the oscillating gear.

[0207] (Note 5)

[0208] According to Appendix 3 or 4, the robot, wherein

[0209] The thermal conductivity of the second component is greater than that of the output shaft.

Claims

1. A gear mechanism, wherein the gear mechanism has: a first gear; a second gear that meshes with the first gear; a shaft that is inserted into the second gear, transmits a rotational force to the second gear, or transmits a rotational force of the second gear; and a support portion that supports an axial end portion of the shaft in a manner in which the shaft is rotatable, the shaft has, at least partially throughout an axial direction of the shaft, a shaft-side high thermal conductivity portion that has a higher thermal conductivity than the second gear, the support portion has, for each of the shafts, a recess formed around the shaft, the recesses are each independently formed in a manner in which they do not communicate with each other and in a manner in which an outer peripheral surface of the axial end portion of the shaft is exposed, in the recess, a support-portion-side high thermal conductivity portion that has a higher thermal conductivity than the second gear and the support portion is received in contact with the outer peripheral surface of the shaft.

2. The gear mechanism according to claim 1, wherein the shaft has a tubular portion that extends throughout the axial direction of the shaft, the shaft-side high thermal conductivity portion is provided inside the tubular portion and is in contact with an inner peripheral surface of the tubular portion, the tubular portion has a higher rigidity than the shaft-side high thermal conductivity portion.

3. The gear mechanism according to claim 2, wherein the shaft-side high thermal conductivity portion has a thermal conductivity that is higher than a thermal conductivity of the tubular portion and is 100 W / m K or more.

4. The gear mechanism according to claim 2 or 3, wherein the shaft-side high thermal conductivity portion includes a heat pipe.

5. The gear mechanism according to claim 1, wherein the support-portion-side high thermal conductivity portion includes grease.

6. The gear mechanism according to claim 1 or 2, wherein the support-portion-side high thermal conductivity portion has a thermal conductivity of 5 W / m K or more.

7. The gear mechanism according to claim 1 or 2, wherein the gear mechanism has a counterpart member for the support portion to be mounted, the counterpart member has a thermal conductivity that is the same as or higher than a thermal conductivity of the shaft-side high thermal conductivity portion.

8. The gear mechanism according to claim 1 or 2, wherein the first gear includes a ring gear having internal teeth, the second gear includes a swing gear that has external teeth that mesh with the internal teeth and that swings and rotates, the shaft includes at least either an input crankshaft that transmits a rotational force to the swing gear or an output shaft that transmits a rotational force of the swing gear, the input crankshaft has an eccentric portion that supports the swing gear so as to be rotatable, the output shaft is disposed around the input crankshaft and is inserted into the swing gear.

9. The gear mechanism according to claim 8, wherein the ring gear has: a cylindrical housing; and a plurality of internal tooth pins that are arranged in a circumferential direction on an inner peripheral surface of the housing, the housing has a higher thermal conductivity than a thermal conductivity of the internal tooth pins and a thermal conductivity of the swing gear.

10. The gear mechanism according to claim 8, wherein the ring gear has: a cylindrical housing; and a plurality of internal tooth pins that are arranged in a circumferential direction on an inner peripheral surface of the housing, the housing has a higher thermal conductivity than a thermal conductivity of the swing gear. ​ The inner tooth pin has a higher thermal conductivity than the oscillating gear.

11. The gear mechanism according to claim 8, wherein The oscillating gear is formed of resin.

12. A robot, wherein The robot is provided with: a first member and a second member; and a gear mechanism provided between the first member and the second member to rotate the second member relative to the first member, The gear mechanism is provided with: an inner tooth gear fixed to the first member and having inner teeth; an oscillating gear having outer teeth that mesh with the inner teeth of the inner tooth gear and that oscillate and rotate; an input crankshaft having an eccentric portion that supports the oscillating gear so as to be rotatable, and that transmits a rotational force to the oscillating gear; an output shaft disposed around the input crankshaft and inserted in the oscillating gear, and that transmits a rotational force of the oscillating gear; and a support portion that supports both axial end portions of the output shaft so as to be rotatable, and that is fixed to the second member, At least either one of the input crankshaft and the output shaft has a shaft-side high thermal conductivity portion that is provided integrally in at least a part of the entire shaft in the axial direction and has a higher thermal conductivity than the oscillating gear, The support portion has, for each of the output shafts, a recess portion formed around the output shaft, The recess portions are respectively independently formed so as not to communicate with each other, and are formed so as to expose an outer peripheral surface of an axial end portion of the output shaft, In the recess portion, a support-portion-side high thermal conductivity portion having a higher thermal conductivity than the oscillating gear and the support portion is received in contact with the outer peripheral surface of the output shaft. ​

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