Rotating mechanisms and robots

Abstract

This invention relates to rotary mechanisms and robots. One embodiment of the present invention, a reduction mechanism (1B), comprises an output shaft (9), gear carriers (13, 14) having output shaft holes (13b, 14b), and oscillating gears (11, 12) having output shaft insertion holes (25a, 25b). The output shaft holes (13b, 14b) and the output shaft insertion holes (25a, 25b) are for insertion of the output shaft (9) and are in contact with the output shaft (9) on their inner circumferential surfaces. The surface roughness Ra of the inner circumferential surfaces of the output shaft holes (13b, 14b) and the output shaft insertion holes (25a, 25b) is 1.6 μm or less, and the coefficient of static friction of the inner circumferential surfaces relative to the output shaft (9) is 0.2 or less.

Description

Technical Field

[0001] This invention relates to rotating 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, jointed collaborative robots, a reduction gear is provided at the joint connecting the two arms as a rotational mechanism. For example, jointed collaborative robots may include an electric motor that applies rotational force to the reduction gear. By reducing and outputting the rotational force of the electric motor, a larger output torque can be applied to the other arm relative to the first arm.

[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. This speed reduction mechanism includes, for example, a housing with an internal gear formed on its inner circumferential surface, an oscillating gear (external gear) that meshes with the internal gear and oscillates and rotates, an input crankshaft (first rotating part) having an eccentric part (eccentric body) that supports the oscillating gear and transmits rotational force to the oscillating gear, an output shaft (gear carrier pin) that transmits the rotational force of the oscillating gear, and a support part (gear carrier) connected to the output shaft. The support part is rotatably supported on the housing via a sliding bearing. The output shaft is pressed into a hole formed in the support part (press-in hole) and is integrated with the support part. Thus, when the rotational force of the oscillating gear is transmitted to the output shaft, the support part rotates relative to the housing.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-17362 Summary of the Invention

[0007] The problem the invention aims to solve

[0008] However, in the aforementioned prior art, because an output shaft is pressed into the support, the assembly and disassembly of the reduction mechanism are quite cumbersome. Since the output shaft does not rotate freely relative to the support, the limiting PV value of the support and output shaft is low, potentially leading to aging and other defects. Therefore, it is difficult to ensure stable operation of the reduction mechanism, which may reduce its product lifespan.

[0009] This invention provides a rotating mechanism and a robot that can improve assembly and disassembly workability, stabilize operation, and extend product life.

[0010] Solution for solving the problem

[0011] A rotating mechanism according to one embodiment of the present invention comprises: a shaft; and a rotating body having a shaft insertion hole for inserting the shaft and contacting the shaft on its inner circumferential surface, the rotating body being rotatable relative to the shaft, the surface roughness Ra of the inner circumferential surface being 1.6 μm or less, and the static friction coefficient of the inner circumferential surface relative to the shaft being 0.2 or less.

[0012] This configuration improves the ease of assembly and disassembly of the rotating body and shaft. The surface roughness Ra of the inner circumferential surface of the rotating body is set to 1.6 μm or less, and the static friction coefficient of the inner circumferential surface of the rotating body relative to the shaft is set to 0.2 or less. Therefore, the sliding resistance between the shaft and the rotating body is reduced, and the limiting PV value of the rotating body is increased. This, in turn, ensures stable operation of the rotating mechanism and extends product life.

[0013] In the above structure, the portion of the rotating body that includes at least the inner circumferential surface and surrounds the shaft may be formed of resin, and the shaft may be formed of metal.

[0014] In the above structure, the rotating mechanism may also include: an internal gear having internal teeth; a oscillating gear having external teeth that mesh with the internal teeth of the internal gear and oscillating and rotating; an input crankshaft having an eccentric portion that supports the oscillating gear for rotational freedom; an output shaft that transmits the rotational force of the oscillating gear; and a support portion that supports both axial ends of the output shaft in a manner that allows the output shaft to rotate freely. The input crankshaft transmits rotational force to the oscillating gear, the shaft includes the output shaft, the rotating body includes the oscillating gear and the support portion, and the shaft insertion hole includes a gear-side shaft hole formed in the oscillating gear and a support-side shaft hole formed in the support portion.

[0015] In the above structure, the rotating mechanism may also have a shim disposed at at least one of the two axial ends of the output shaft, the shim being used to position the output shaft in the axial direction.

[0016] In the above structure, the gasket may also be an elastic gasket capable of elastic deformation.

[0017] In the above structure, the gasket may also have an annular spacer into which the output shaft is inserted.

[0018] In the above structure, the internal gear may also include: a cylindrical outer shell; and a plurality of internal 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.

[0019] 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.

[0020] Another technical solution of the present invention provides a rotating mechanism comprising: an internal gear having internal teeth; an oscillating gear formed of resin and oscillating and rotating; an input crankshaft formed of metal and transmitting rotational force to the oscillating gear; an output shaft formed of metal and transmitting the rotational force of the oscillating gear; and a support portion formed of resin and supporting the axial ends of the output shaft in a rotatable manner, wherein the oscillating gear has external teeth that mesh with the internal teeth of the internal gear, and the input crankshaft has an eccentric portion that supports the oscillating gear for rotational rotation.

[0021] By employing this configuration, when using an eccentric oscillating reduction mechanism as the rotating mechanism, the static friction coefficient of the inner circumferential surfaces of the gear side shaft hole and the support side shaft hole relative to the output shaft can be easily reduced. The limiting PV value of the oscillating gear and the support can be easily increased. Therefore, the rotating mechanism can operate stably, extending product life. Using metal to form the output shaft increases its rigidity, further stabilizing the rotating mechanism and further extending product life.

[0022] Another embodiment of the present invention provides a robot comprising: a first component and a second component; and a rotating mechanism disposed between the first component and the second component, the rotating mechanism causing the second component to rotate relative to the first component, the rotating mechanism comprising: an internal gear having internal teeth; an oscillating gear formed of resin and oscillating and rotating; an input crankshaft formed of metal and transmitting rotational force to the oscillating gear; an output shaft formed of metal and transmitting the rotational force of the oscillating gear; and a support portion formed of resin and supporting the axial ends of the output shaft in a rotatable manner, the oscillating gear having external teeth meshing with the internal teeth of the internal gear, and the input crankshaft having an eccentric portion supporting the oscillating gear for rotatability.

[0023] This configuration allows for the creation of a robot that can operate stably and extend product lifespan.

[0024] The effects of the invention

[0025] The aforementioned rotating mechanism and robot can improve assembly and disassembly workability, stabilize operation, and extend product life. Attached Figure Description

[0026] Figure 1This is a schematic structural diagram of a collaborative robot according to an embodiment of the present invention.

[0027] Figure 2 This is a schematic structural diagram of the second deceleration mechanism according to the first embodiment of the present invention.

[0028] Figure 3 This is a schematic structural diagram of the deceleration mechanism according to the second embodiment of the present invention.

[0029] Explanation of reference numerals in the attached figures

[0030] 1A, 1B, 1C, 201, Reduction mechanism (rotary mechanism); 2, Housing (internal gear); 6, Internal gear pin (internal gear); 7, Gear carrier (rotating body, support); 8, Input crankshaft; 9, Output shaft (shaft); 9a, First end (end); 9b, Second end (end); 11, First oscillating gear (rotating body, oscillating gear); 12, Second oscillating gear (rotating body, oscillating gear); 13, First gear carrier (rotating body, support); 13b, 14b, Output shaft hole (shaft insertion hole, support side shaft hole); 14, Second gear carrier (rotating body, support); 21a, First eccentric part (eccentric part) 21b, Second eccentric part (eccentric part); 23a, 23b, External teeth; 25a, First output shaft insertion hole (shaft insertion hole, gear side shaft hole); 25b, Second output shaft insertion hole (shaft insertion hole, gear side shaft hole); 42, Elastic shim (shim); 43, Spacer (shim); 100, Collaborative robot (robot); 101, Base part (first component, second component); 102, Rotating head (first component, second component); 103, Arm unit (first component, second component); 111, First arm (first component, second component); 112, Second arm (first component, second component). Detailed Implementation

[0031] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[0032] Collaborative Robots

[0033] Figure 1 This is a schematic diagram of the collaborative robot 100.

[0034] 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.

[0035] like Figure 1As 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, 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, 1B, 1C (the first reduction mechanism). The system includes a speed reduction mechanism 1A, a second speed reduction mechanism 1B, and a third speed reduction mechanism 1C, which are assembled on the base 101, the rotating head 102, and the joints 106a, 106b, and 106c (first joint 106a, second joint 106b, and third joint 106c) of the arm unit 103; servo motors 107, 108, and 109 (first servo motor 107, second servo motor 108, and third servo motor 109), which serve as drive sources; and an end effector 110, which is mounted on the arm unit 103.

[0036] The rotating head 102 is rotatably connected to the base portion 101 about the first rotation axis L1. The connection point is the first joint portion 106a. The first reduction mechanism 1A and the first servo motor 107 are assembled in the first joint portion 106a.

[0037] 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 1A. As a result, the rotary head 102 is driven to rotate relative to the base portion 101 about the first rotation axis L1.

[0038] The arm unit 103 is, for example, composed of 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.

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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].

[0044] [First Implementation]

[0045] <Speed ​​Reduction Mechanism>

[0046] Next, based on Figure 2 The deceleration mechanisms 1A to 1C are described below.

[0047] 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.

[0048] Figure 2 This is a schematic structural diagram of the second deceleration mechanism 1B.

[0049] like Figure 2 As 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 an internal gear in the claims) 2, a gear carrier (an example of a support in the claims) 7 rotatably supported on the housing 2, an input crankshaft 8 rotatably supported on the gear carrier 7, a plurality of (e.g., 3) output shafts 9, and oscillating gears 11 and 12 (first oscillating gear 11 and second oscillating gear 12) rotatably supported on the input crankshaft 8.

[0050] 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.

[0051] 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.

[0052] An outer flange 4 protruding radially outward is integrally formed at the center of the outer peripheral surface 2a of the outer casing 2. The cross-section of the outer flange 4 along the axial direction is quadrilateral.

[0053] 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.

[0054] 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.

[0055] A plurality of internal toothed pins (an example of an 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 are formed of metal, for example. In addition, the internal toothed pins 6 can be formed of resin with high thermal conductivity, non-metals, etc. The internal toothed pins 6 can also be a resin 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).

[0056] 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.

[0057] 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.

[0058] The gear carrier 7 is composed of a first gear carrier (shaft flange) 13 and a second gear carrier (retaining flange) 14. The first gear carrier 13 is provided 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, and the second gear carrier 14 is provided on the second expanded diameter portion 3b on the side opposite to the first expanded diameter portion 3a in the axial direction.

[0059] 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.

[0060] 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]. It is desirable that the coefficient of linear expansion of each gear carrier 13, 14 is, for example, the coefficient of linear expansion of aluminum alloy (23-24 × 10⁻⁶). －6 / ℃)) or above.

[0061] An axially penetrating input shaft hole 13a, 14a is formed at the radial center of each gear carrier 13, 14. The input crankshaft 8 is inserted into the input shaft hole 13a, 14a.

[0062] 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 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.

[0063] Each gear carrier 13, 14 has a plurality (e.g., 3) of output shaft holes (an example of shaft insertion holes and support-side shaft holes in the claims) 13b, 14b formed at equal intervals along the circumferential direction around the input shaft holes 13a, 14a. An output shaft 9 is inserted into the output shaft holes 13b, 14b. The surface roughness Ra of the inner circumferential surfaces of the output shaft holes 13b, 14b is 1.6 μm or less. The coefficient of static friction of the inner circumferential surfaces of the output shaft holes 13b, 14b relative to the output shaft 9 is 0.2 or less.

[0064] On a surface 13c of the first gear carrier 13, opposite to the second gear carrier 14, a shim receiving recess 41 is formed on the same axis as the output shaft hole 13b. The shim receiving recess 41 has an opening on one surface 13c and communicates with the output shaft hole 13b.

[0065] A circular elastic washer (an example of the washer in the claims) 42 is housed in the washer receiving recess 41. The inner diameter of the elastic washer 42 is approximately the same as or slightly larger than the inner diameter of the output shaft hole 13b. The elastic washer 42 is made of rubber or the like and is capable of elastic deformation. The elastic washer 42 may also be made of a material other than rubber, as long as it is made of a material capable of elastic deformation. For example, a corrugated washer may be used instead of rubber as the elastic washer 42.

[0066] An annular spacer (an example of a spacer in the claims) 43 is disposed on the elastic washer 42. The inner diameter of the spacer 43 is approximately the same as or slightly larger than the inner diameter of the output shaft hole 13b. The spacer 43 is, for example, made of metal. The elastic washer 42 and the spacer 43 are used for positioning the output shaft 9 relative to the gear carriers 13, 14 (details described later).

[0067] 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.

[0068] For example, grease (not shown) can be filled into the recess 16. The grease is used to dissipate heat transferred to the output shaft 9. The thermal conductivity of the grease is higher than that of the oscillating gears 11, 12 and the second gear carrier 14. The thermal conductivity of the grease is 5 [W / m·K] or higher.

[0069] The output shaft 9, inserted into the output shaft holes 13b and 14b, is made of, for example, aluminum alloy. The output shaft 9 is not limited to aluminum alloy; it 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].

[0070] The first end 9a of the output shaft 9 on the side of the first gear carrier 13 slightly protrudes from a surface 13c on the side of the first gear carrier 13 opposite to the second gear carrier 14. An elastic washer 42 and a spacer 43 are mounted on the first end 9a of the output shaft 9. A first retaining ring 18a is mounted on the spacer 43 at the first end 9a of the output shaft 9. The first retaining ring 18a abuts against the spacer 43, thereby restricting the movement of the output shaft 9 toward the second gear carrier 14.

[0071] The second end 9b of the output shaft 9 on the side of the second gear carrier 14 is located 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 the recess 16 of the second gear carrier 14. A second retaining ring 18b is installed on the second end 9b of the output shaft 9. The second retaining ring 18b is also housed within the recess 16. By abutting against the bottom surface 16a of the recess 16, the movement of the output shaft 9 toward the first gear carrier 13 is restricted.

[0072] That is, the elastic shim 42, the spacer 43, and the retaining rings 18a and 18b have the function of positioning the output shaft 9 relative to the gear carriers 13 and 14. Specifically, the elastic shim 42 and the spacer 43 have the function of absorbing manufacturing errors in the housing 2, the gear carriers 13 and 14, and the output shaft 9 to adjust the position of the output shaft 9 relative to the gear carriers 13 and 14. In other words, the axial thickness of the elastic shim 42 and the spacer 43 is adjusted according to the degree of axial looseness of the output shaft 9 relative to the gear carriers 13 and 14 to suppress axial looseness of the output shaft 9 relative to the gear carriers 13 and 14. This looseness refers to the looseness caused by gaps that allow the output shaft 9 to move axially relative to the gear carriers 13 and 14 due to manufacturing errors in the housing 2, the gear carriers 13 and 14, and the output shaft 9.

[0073] The axial thickness of the elastic shim 42 is determined to be slightly compressed. Therefore, the restoring force generated by the installed elastic shim 42 applies force to the first gear carrier 13 towards the second gear carrier 14. As a result, loosening of each gear carrier 13, 14, and output shaft 9 is reliably suppressed. Even if the axial loosening of the output shaft 9 relative to each gear carrier 13, 14 increases due to years of deterioration, the elastic shim 42 can absorb this loosening. By applying force to the first gear carrier 13 towards the second gear carrier 14, preload is also applied to each bearing 15a, 15b provided in each input shaft hole 13a, 14a of each gear carrier 13, 14.

[0074] Since the axial movement of the output shaft 9 relative to each gear carrier 13, 14 is restricted, in other words, the axial movement of each gear carrier 13, 14 is restricted. Therefore, 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 becoming a configuration around the input crankshaft 8.

[0075] The input crankshaft 8, like the output shaft 9, is made of, for example, aluminum alloy. In addition, the input crankshaft 8 can be made of, for example, stainless steel or various ferrous metals, just like the output shaft 9.

[0076] 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 the first end 8a. The rotation of the second servo motor 108 is transmitted to the input crankshaft 8.

[0077] 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.

[0078] 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 expanded diameter portion 20, larger than the diameter of the eccentric portions 21a and 21b, is formed between each eccentric portion 21a and 21b on the input crankshaft 8.

[0079] 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°.

[0080] Bearings 15c and 15d (the third bearing 15c and the fourth bearing 15d) are respectively provided in each eccentric portion 21a and 21b. 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 bearings 15c and 15d is limited by their axial end faces abutting against 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.

[0081] 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.

[0082] 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.

[0083] External teeth 23a and 23b are formed on the outer periphery of the two oscillating gears 11 and 12, which 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.

[0084] Two oscillating gears 11 and 12 have output shaft insertion holes 25a and 25b (first output shaft insertion hole 25a, second output shaft insertion hole 25b; an example of shaft insertion hole and gear side shaft hole in the claims) formed at positions corresponding to the output shaft 9. The inner diameter of each output shaft insertion hole 25a and 25b is such that the oscillating gears 11 and 12 can oscillate and rotate when the output shaft 9 is inserted into the output shaft insertion hole 25a and 25b.

[0085] The surface roughness Ra of the inner circumferential surfaces of the output shaft insertion holes 25a and 25b is less than 1.6 μm. The static friction coefficient of the inner circumferential surfaces of the output shaft insertion holes 25a and 25b relative to the output shaft 9 is less than 0.2.

[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] By inserting the output shaft 9 into the output shaft holes 13b and 14b formed in each gear carrier 13 and 14, the output shaft 9 and each gear carrier 13 and 14 are integrated. Thus, the output shaft 9 can rotate freely relative to each gear carrier 13 and 14. Furthermore, by using resin to form each gear carrier 13 and 14, bearings do not need to be separately provided with each gear carrier 13 and 14, allowing the output shaft 9 to be rotatably supported on each gear carrier 13 and 14.

[0097] The surface roughness Ra of the inner circumferential surfaces of the output shaft holes 13b and 14b is 1.6 μm or less. The static friction coefficient of the inner circumferential surfaces of the output shaft holes 13b and 14b relative to the output shaft 9 is 0.2 or less. As a result, the sliding resistance of the output shaft 9 relative to each gear carrier 13 and 14 can be reduced, allowing the output shaft 9 to rotate smoothly relative to each gear carrier 13 and 14.

[0098] This situation can also be explained by the relationship between each oscillating gear 11, 12 and the output shaft 9. Specifically, each oscillating gear 11, 12 is formed of resin. The surface roughness Ra of the inner circumferential surfaces of the output shaft insertion holes 25a, 25b formed on each oscillating gear 11, 12 is 1.6 μm or less. The coefficient of static friction between the inner circumferential surfaces of the output shaft insertion holes 25a, 25b and the output shaft 9 is 0.2 or less. Therefore, without the need for separate bearings for each oscillating gear 11, 12, the output shaft 9 can smoothly contact each oscillating gear 11, 12.

[0099] 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.

[0100] The input crankshaft 8 and output shaft 9 are, for example, made of aluminum alloy. The thermal conductivity of the input crankshaft 8 and output shaft 9 is higher than that of the oscillating gears 11 and 12.

[0101] 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.

[0102] 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. Heat is dissipated via each end 8a and 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, for example, formed of aluminum alloy, and therefore has a thermal conductivity 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.

[0103] 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. Heat is dissipated through each end 9a and 9b.

[0104] A recess 16 is formed around the second end 9b of the output shaft 9 on the second gear carrier 14. The recess 16 is filled with grease. 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. Consequently, heat transferred from the output shaft 9 to the first arm 111 is effectively dissipated.

[0105] The outer casing 2 is made of, for example, aluminum alloy. The internal toothed pin 6 can be made of a metallic material, a resin with high thermal conductivity, a non-metallic material, etc. The oscillating gears 11 and 12 are made of, for example, resin. The thermal conductivity of the outer casing 2 is higher than that of the oscillating gears 11 and 12. 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. Therefore, heat retention inside the second reduction mechanism 1B is suppressed.

[0106] Regarding the heat dissipation effect described above, the first reduction mechanism 1A and the third reduction mechanism 1C also function similarly. Heat trapped inside the first reduction mechanism 1A and the third reduction mechanism 1C is dissipated through the input crankshaft 8 and the output shaft 9. Heat is effectively dissipated by transferring heat to the rotating head 102, the second arm 112, etc., via the input crankshaft 8 and the output shaft 9. The housing 2 and the internal gear pin 6 effectively prevent heat from remaining inside each reduction mechanism 1A and 1C.

[0107] Thus, in the aforementioned reduction mechanisms 1A, 1B, and 1C, the surface roughness Ra of the inner circumferential surfaces of the output shaft holes 13b and 14b formed in each gear carrier 13 and 14, which are rotating bodies, is 1.6 μm or less. The static friction coefficient of the inner circumferential surfaces of the output shaft holes 13b and 14b relative to the output shaft 9 is 0.2 or less. Similarly, the surface roughness Ra of the inner circumferential surfaces of the output shaft insertion holes 25a and 25b formed in each oscillating gear 11 and 12, which are rotating bodies, is 1.6 μm or less. The static friction coefficient of the inner circumferential surfaces of the output shaft insertion holes 25a and 25b relative to the output shaft 9 is 0.2 or less.

[0108] Therefore, without the need for independent bearings for each gear carrier 13 and 14, the output shaft 9 can be smoothly and freely supported on each gear carrier 13 and 14. Without the need for independent bearings for each oscillating gear 11 and 12, the output shaft 9 can smoothly contact each oscillating gear 11 and 12. This improves the limiting PV value of each gear carrier 13 and 14 and each oscillating gear 11 and 12. Therefore, the reduction mechanisms 1A, 1B, and 1C can operate stably, extending product life.

[0109] For the contact between each gear carrier 13, 14, each oscillating gear 11, 12 and the output shaft 9, there is no need to install bearings, which allows the reduction mechanisms 1A, 1B and 1C to be miniaturized accordingly.

[0110] In addition, the linear expansion coefficients of each gear carrier 13 and 14 are, for example, the linear expansion coefficients of aluminum alloy (23-24 × 10⁻⁶). －6 / ℃)) or above. On the other hand, the output shaft 9 is, for example, made of aluminum alloy. Therefore, even if the temperature of each gear carrier 13, 14 rises due to driving the reduction mechanisms 1A, 1B, 1C, the outer diameter of the output shaft 9 will not become excessively large relative to the inner diameter of the output shaft holes 13b, 14b. The output shaft 9 can be smoothly and freely supported on each gear carrier 13, 14.

[0111] Output shafts 9 are inserted into the output shaft holes 13b and 14b of each gear carrier 13 and 14. Therefore, compared with pressing the output shafts 9 into and fixing them to each gear carrier 13 and 14, the assembly and disassembly of each reduction mechanism 1A, 1B, and 1C can be improved.

[0112] By using resin to form each gear carrier 13, 14 and each oscillating gear 11, 12, the surface roughness Ra of the inner circumferential surfaces of the output shaft holes 13b, 14b and the output shaft insertion holes 25a, 25b can be easily made to be 1.6 μm or less. The static friction coefficient of the inner circumferential surfaces of the output shaft holes 13b, 14b and the output shaft insertion holes 25a, 25b relative to the output shaft 9 can be easily made to be 0.2 or less.

[0113] By using metal to form the output shaft 9, its rigidity can be improved. Therefore, the reduction mechanisms 1A, 1B, and 1C can operate more stably, extending the product life.

[0114] In the eccentric oscillating type reduction mechanisms (reduction mechanisms 1A, 1B, 1C), as described above, by using a first gear carrier 13 with output shaft holes 13b and 14b and a second gear carrier 14 with output shaft insertion holes 25a and 25b, miniaturization of each reduction mechanism 1A, 1B, and 1C can be achieved, and drive efficiency can be improved. The limiting PV values ​​of each gear carrier 13 and 14, and each oscillating gear 11 and 12, can be easily improved, and the rigidity of the output shaft 9 can also be increased. Therefore, each reduction mechanism 1A, 1B, and 1C can operate reliably and stably. The product life of each reduction mechanism 1A, 1B, and 1C can be extended.

[0115] An elastic washer 42 and a spacer 43 are provided on the first end 9a side of the output shaft 9. Therefore, the output shaft 9 can be easily and accurately positioned relative to each gear carrier 13, 14. The elastic washer 42 and the spacer 43 can absorb manufacturing errors in the housing 2, each gear carrier 13, 14, and the output shaft 9. The elastic washer 42 and the spacer 43 can be used to adjust the position of the output shaft 9 relative to each gear carrier 13, 14.

[0116] Two components (elastic shim 42 and spacer 43) are used for adjusting the position of the output shaft 9, thus allowing for variations in the position adjustment method through the combination of these two components. Therefore, the output shaft 9 can be positioned relative to each gear carrier 13, 14 more easily and with higher precision, and loosening of the output shaft can be suppressed.

[0117] In particular, the elastic shim 42 is capable of elastic deformation. Therefore, by installing the elastic shim 42 with slight axial compression deformation, the restoring force generated by the elastic shim 42 can be used to apply force to the first gear carrier 13 towards the second gear carrier 14 side. As a result, loosening of each gear carrier 13, 14 and the output shaft 9 can be reliably suppressed. Even if the output shaft 9 becomes looser in the axial direction relative to each gear carrier 13, 14 due to years of deterioration, the elastic shim 42 can absorb the loosening. By applying force to the first gear carrier 13 towards the second gear carrier 14 side, preload can also be applied to each bearing 15a, 15b provided in each input shaft hole 13a, 14a of each gear carrier 13, 14.

[0118] In the reduction mechanisms 1A, 1B, and 1C, the thermal conductivity of the outer casing 2 is higher than that of each oscillating gear 11 and 12. Therefore, the heat inside the reduction mechanisms 1A, 1B, and 1C can be efficiently dissipated through the outer casing 2.

[0119] The thermal conductivity of the outer casing 2 is higher than that of the inner tooth pin 6, thereby enabling the heat trapped in the inner tooth pin 6 to be actively transferred to the outer casing 2. As a result, the heat in the reduction mechanisms 1A, 1B, and 1C can be efficiently dissipated through the outer casing 2.

[0120] By using the aforementioned deceleration mechanisms 1A, 1B, and 1C at the joints 106a, 106b, and 106c of the collaborative robot 100, the movement of the collaborative robot 100 can be stabilized, thereby extending the product lifespan of the collaborative robot 100.

[0121] In the first embodiment described above, the case where an elastic washer 42 and a spacer 43 are provided at the first end 9a side of the output shaft 9 has been explained. However, it is not limited to this; the elastic washer 42 and the spacer 43 may also be provided at the second end 9b side of the output shaft 9. The elastic washer 42 and the spacer 43 may also be provided at both ends 9a and 9b of the output shaft 9. Either the elastic washer 42 or the spacer 43 may be provided.

[0122] [Second Implementation]

[0123] <Speed ​​Reduction Mechanism>

[0124] Next, quote Figure 1 ,based on Figure 3 The second embodiment will be described.

[0125] 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.

[0126] 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.

[0127] 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 8, an output shaft 9, and oscillating gears 11 and 12.

[0128] The difference between the first and second embodiments described above is as follows: In the first embodiment, an elastic washer 42 is provided on the first end 9a side of the output shaft 9, while in the second embodiment, the elastic washer 42 is not provided.

[0129] That is, a shim receiving recess 41 is not formed on one surface 13c of the first gear carrier 13 (see reference). Figure 2 The first gear carrier 13 has a surface 13c that is generally flat. Only a spacer 43 is provided on the first end 9a side of the output shaft 9.

[0130] Even with this configuration, it achieves the same effect as the first embodiment described above.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] In the above embodiments, the reduction mechanisms 1A-1C and 201 are described as so-called eccentric oscillating type reduction mechanisms, having a central crankshaft (input crankshaft 8) 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 in conjunction. In this case, the input crankshaft 8 itself revolves around the central axis C1 while rotating on its own axis.

[0135] 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.

[0136] In the above embodiments, the case where each gear carrier 13, 14 is formed of resin, for example, has been described. However, it is not limited to this, as long as the surface roughness Ra of the inner circumferential surface of the output shaft holes 13b, 14b is 1.6 μm or less, and the static friction coefficient of the inner circumferential surface of the output shaft holes 13b, 14b relative to the output shaft 9 is 0.2 or less.

[0137] For example, gear carriers 13 and 14 can be formed using materials other than resin, and the inner circumferential surfaces of the output shaft holes 13b and 14b can be processed with fluoropolymer resin. Alternatively, only the area around the output shaft 9 in each gear carrier 13 and 14, including at least the inner circumferential surfaces of the output shaft holes 13b and 14b, can be formed using resin. Alternatively, gear carriers can be formed using sintered metal or castings. Again, only the area around the output shaft 9, including the inner circumferential surfaces of the output shaft holes 13b and 14b, can be formed using sintered metal or castings.

[0138] In the above embodiments, the case where the elastic pad 42 and the spacer 43 are annular has been described. The case where they are installed at the first end 9a of the output shaft 9 has been described. However, it is not limited to this; any shape that can absorb manufacturing errors of the housing 2, the gear carriers 13 and 14, and the output shaft 9 using the elastic pad 42 and the spacer 43 is acceptable. Any shape that allows for position adjustment of the output shaft 9 relative to the gear carriers 13 and 14 using the elastic pad 42 and the spacer 43 is acceptable. For example, the elastic pad 42 and the spacer 43 can also be formed in a U-shape. In this case, it is preferable, for example, that the pad receiving recess 41 formed on the first gear carrier 13 receives not only the elastic pad 42 but also the spacer 43. With this configuration, the elastic pad 42 and the spacer 43 can be prevented from falling off regardless of their shape.

[0139] 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.

Claims

1. A rotating mechanism, wherein, This rotating mechanism has the following features: Internal gear, which has internal teeth; A oscillating gear having external teeth that mesh with the internal teeth of the internal gear, and oscillating and rotating; An input crankshaft has an eccentric portion that supports the oscillating gear as a rotatable component and transmits rotational force to the oscillating gear. The output shaft transmits the rotational force of the oscillating gear; as well as A support portion that rotatably supports both axial ends of the output shaft. The oscillating gear has a gear-side shaft hole for the output shaft to be inserted into and for contacting the output shaft on the inner circumferential surface of the gear side. The support portion has a support-side shaft hole for inserting the output shaft and for contacting the output shaft on the inner circumferential surface of the support portion. The rotating mechanism has a rubber, annular elastic washer that fits into at least one of the two axial ends of the output shaft to position the output shaft in the axial direction. A shim receiving recess is formed in the support portion, which communicates with the side shaft hole of the support portion and is formed on the same axis as the side shaft hole of the support portion. The elastic gasket is fitted into the gasket receiving recess. The surface roughness Ra of the inner circumferential surface on the gear side and the inner circumferential surface on the support side is less than 1.6 μm. The static friction coefficients of the inner circumferential surface of the gear side and the inner circumferential surface of the support side relative to the output shaft are 0.2 or less.

2. The rotating mechanism according to claim 1, wherein, The portions of the oscillating gear and the support portion, including at least the inner circumferential surfaces of the gear side and the support portion side and surrounding the output shaft, are formed of resin. The output shaft is made of metal.

3. The rotating mechanism according to claim 1 or 2, wherein, The rotating mechanism has an annular spacer into which the output shaft is inserted.

4. The rotating mechanism according to claim 1 or 2, wherein, The internal gear has: A cylindrical outer shell; and Multiple internal toothed pins are arranged circumferentially on the inner circumferential surface of the housing. The thermal conductivity of the outer casing is higher than that of the oscillating gear.

5. The rotating mechanism according to claim 1 or 2, wherein, The internal gear has: A cylindrical outer shell; and Multiple internal toothed pins are arranged circumferentially on the inner circumferential surface of the housing. The thermal conductivity of the outer shell is higher than that of the inner toothed pin.

6. A rotating mechanism, wherein, This rotating mechanism has the following features: Internal gear, which has internal teeth; A oscillating gear, formed of resin, having external teeth that mesh with the internal teeth of the internal gear, and oscillating and rotating; An input crankshaft, which is formed of metal, has an eccentric portion that supports the oscillating gear as a freely rotatable part and transmits rotational force to the oscillating gear; The output shaft, which is made of metal, transmits the rotational force of the oscillating gear; as well as The support portion, formed of resin, supports both axial ends of the output shaft in a manner that allows the output shaft to rotate freely. The oscillating gear has a gear-side shaft hole for the output shaft to be inserted into and for contacting the output shaft on the inner circumferential surface of the gear side. The support portion has a support-side shaft hole for inserting the output shaft and for contacting the output shaft on the inner circumferential surface of the support portion. The rotating mechanism has a rubber, annular elastic washer that fits into at least one of the two axial ends of the output shaft to position the output shaft in the axial direction. A shim receiving recess is formed in the support portion, which communicates with the side shaft hole of the support portion and is formed on the same axis as the side shaft hole of the support portion. The elastic pad is fitted into the pad receiving recess.

7. A robot, wherein, This robot has the following features: Component 1 and Component 2; and A rotating mechanism is disposed between the first component and the second component. The rotating mechanism causes the second component to rotate relative to the first component. The rotating mechanism includes: Internal gear, which has internal teeth; A oscillating gear, formed of resin, having external teeth that mesh with the internal teeth of the internal gear, and oscillating and rotating; An input crankshaft, which is formed of metal, has an eccentric portion that supports the oscillating gear as a freely rotatable part and transmits rotational force to the oscillating gear; The output shaft, which is made of metal, transmits the rotational force of the oscillating gear; The support portion, formed of resin, supports both axial ends of the output shaft in a manner that allows the output shaft to rotate freely. The oscillating gear has a gear-side shaft hole for the output shaft to be inserted into and for contacting the output shaft on the inner circumferential surface of the gear side. The support portion has a support-side shaft hole for inserting the output shaft and for contacting the output shaft on the inner circumferential surface of the support portion. The rotating mechanism has a rubber, annular elastic washer that fits into at least one of the two axial ends of the output shaft to position the output shaft in the axial direction. A shim receiving recess is formed in the support portion, which communicates with the side shaft hole of the support portion and is formed on the same axis as the side shaft hole of the support portion. The elastic pad is fitted into the pad receiving recess.

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