Gearing

Abstract

To inhibit temperature increase of a gear device efficiently.SOLUTION: A gear device 1 includes: a first gear 22g; and a second gear 12 which engages with the first gear. At least the first gear has: a connection member 22 which is formed of a resin and connected to an external member 55; path members 22, 23 disposed on paths leading to the first gear and the connection member; and other members 24, 26, 27 which are members other than the first gear, the second gear, the connection member, and the path members and formed of a resin. The first gear, the connection member, and the path members are formed by the resin having heat conductivity higher than those of the other members.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a gear device. [Background technology]

[0002] In recent years, due to demands for weight reduction in gear devices, it has been proposed to use gears made of resin. However, when resin is used for gears, there are concerns that heat generation at the meshing points of the gears may cause thermal degradation and thermal deformation. Therefore, in conventional gear devices, one of the meshing gears is made from a resin material and the other gear is made from a material with higher thermal conductivity than the resin gear, thereby diffusing the heat and suppressing the temperature rise (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-155313 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the gear device of Patent Document 1 has room for improvement in terms of heat dissipation from the resin gear side.

[0005] An object of the present invention is to efficiently suppress a temperature rise in a gear device. [Means for solving the problem]

[0006] The present invention provides a gear device including a first gear and a second gear meshing with the first gear, At least the first gear is made of resin, a connecting member connected to an external member, a path member arranged on a path from the first gear to the connecting member, and another member other than the first gear, the second gear, the connecting member, and the path member and made of resin, the first gear, the connecting member, and the path member are made of a resin having a higher thermal conductivity than the other members, The other member includes at least a cover that supports an input bearing, A heat transfer path from the first gear to the connecting member is Resin with higher thermal conductivity than the other materials The gear device is configured by the path member without passing through a low thermal conductive resin member made of a low thermal conductive resin having a lower thermal conductivity than the low thermal conductive resin. Effect of the Invention

[0007] According to the present invention, it is possible to efficiently suppress a temperature rise in a gear device. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a gear device according to a first embodiment of the present invention. [Diagram 2] FIG. 5 is a cross-sectional view showing a gear device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [First embodiment] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will now be described in detail with reference to the drawings. Fig. 1 is a cross-sectional view showing a flexure mesh gear device as a gear device according to the first embodiment. In the following, the direction along the rotation axis O1 in the figure is defined as the "axial direction", the direction perpendicular to the rotation axis O1 is defined as the "radial direction", and the rotation direction around the rotation axis O1 is defined as the "circumferential direction".

[0010] As shown in FIG. 1, the flexible mesh gear device 1 is a cylindrical flexible mesh gear device in which an external gear 12 (second gear) is flexibly deformed to transmit rotational motion about a rotation axis O1. Specifically, the flexible mesh gear device 1 includes a vibration exciter shaft 10, an external gear 12 that is flexibly deformed by the vibration exciter shaft 10, a first internal gear 22g and a second internal gear 23g that mesh with the external gear 12, and a vibration exciter bearing 15. Furthermore, the flexible mesh gear device 1 includes a first casing 22, an internal gear member 23, a second casing 24, a first cover 26, a second cover 27, input bearings 31, 32, and a main bearing 33.

[0011] The vibrator shaft 10 is a hollow shaft and includes a vibrator 10A having an elliptical cross section perpendicular to the rotation axis O1, and shaft sections 10B and 10C provided on both sides of the axial direction of the vibrator 10A and having circular cross sections perpendicular to the rotation axis O1. Note that the elliptical shape is not limited to a geometrically strict ellipse, but includes an approximate ellipse. The vibrator shaft 10 rotates around the rotation axis O1, and the center of the cross section perpendicular to the rotation axis O1 of the vibrator 10A coincides with the rotation axis O1. This vibrator shaft 10 is an input shaft that is connected to a drive source (not shown) such as a motor to input a driving force.

[0012] The external gear 12 is a cylindrical flexible metal member having teeth on its outer periphery.

[0013] The first internal gear 22g and the second internal gear 23g rotate around the vibration exciter shaft 10 with the rotation axis O1 as the center. The first internal gear 22g and the second internal gear 23g are arranged side by side in the axial direction and mesh with the external gear 12. Specifically, one of the first internal gear 22g and the second internal gear 23g meshes with teeth on one side of the axial center of the external gear 12, and the other meshes with teeth on the other side of the axial center of the external gear 12. The first internal gear 22g is configured by having internal teeth provided at a corresponding location on the inner periphery of the first casing 22. The second internal gear 23g is configured by having internal teeth provided at a corresponding location on the inner periphery of the internal gear member 23.

[0014] The vibrator bearing 15 is disposed between the vibrator 10A and the external gear 12. The vibrator bearing 15 has a plurality of rolling elements (rollers) 15A and a cage 15C that holds the plurality of rolling elements 15A. The plurality of rolling elements 15A roll with the outer circumferential surface of the vibrator 10A and the inner circumferential surface of the external gear 12 as rolling surfaces. The vibrator bearing 15 may have an inner ring separate from the vibrator 10A and an outer ring separate from the external gear 12.

[0015] Spacer rings 36, 37 are provided on both axial sides of the external gear 12 and the retainer 15C of the vibration exciter bearing 15 as restricting members that come into contact with them and restrict their axial movement.

[0016] The first casing 22 and the second casing 24 are connected to each other by bolts 57, which are connecting members, and cover the radial outside of the first internal gear 22g, the second internal gear 23g, and the external gear 12. Of these, the first casing 22 has internal teeth provided on a portion of its inner periphery, as described above, and is configured integrally with the first internal gear 22g.

[0017] The first casing 22 and the second casing 24 are provided with bolt connection holes 22h, 24h that extend continuously in the axial direction at the end on the anti-load side (the right side in FIG. 1). When the flexible mesh gear device 1 is connected to an external member 55 (e.g., a base-end arm member of a robot) outside the device, the first casing 22 and the second casing 24 are connected to the external member 55 by fastening them together through the bolt connection holes 22h, 24h with a bolt 53 that is a connecting member. These bolt connection holes 22h, 24h are provided at a plurality of positions in the circumferential direction. The first casing 22 and the second casing 24 also have bolt holes 22j, 24j that are separate from the bolt connection holes 22h, 24h, and are connected (temporarily fastened) to each other by the aforementioned bolt 57 that is inserted and screwed into the bolt holes 22j, 24j.

[0018] At least a portion of the internal gear member 23 is disposed radially inside the second casing 24 and radially outside the vibration exciter shaft 10. As described above, the internal gear member 23 has internal teeth provided on a portion of its inner periphery, and is configured integrally with the second internal gear 23g.

[0019] The first cover 26 and the first casing 22 have bolt holes 26k, 22k on the anti-load side, and are connected to each other by bolts 51 inserted and screwed into the bolt holes 26k, 22k. The first cover 26 covers the outer periphery of one end of the vibration exciter shaft 10 .

[0020] The second cover 27 is connected to the internal gear member 23 and covers the outer periphery at the other end of the vibrator shaft 10. The second cover 27 and the internal gear member 23 are provided with bolt connection holes 27h, 23h that extend continuously in the axial direction at the end on the load side (left side in FIG. 1). When the flexible mesh gear device 1 is connected to a driven member 56 outside the device (for example, a tip arm member of a robot), the second cover 27 and the internal gear member 23 are connected to the driven member 56 by bolts 54, which are connecting members, by fastening them together through the bolt connection holes 27h, 23h. These bolt connection holes 27h, 23h are provided at multiple points in the circumferential direction. Further, the second cover 27 and the internal gear member 23 have bolt holes 27j, 23j in addition to the bolt connection holes 27h, 23h, and are connected (temporarily fastened) to each other by bolts 52 inserted and screwed into the bolt holes 27j, 23j.

[0021] The input bearing 31 is, for example, a ball bearing having an inner ring 31a, an outer ring 31b, and rolling elements 31c, and is disposed between the shaft portion 10B of the vibrator shaft 10 and the first cover 26. The first cover 26 rotatably supports the vibrator shaft 10 via the input bearing 31. Note that the input bearing 31 is not limited to a ball bearing, and various bearings may be used, for example, a roller bearing. Also, without having a dedicated inner ring or outer ring, the inner ring may be integrally formed with the vibrator shaft 10, or the outer ring may be integrally formed with the first cover 26. The input bearing 32 is, for example, a ball bearing having an inner ring 32a, an outer ring 32b, and rolling elements 32c, and is disposed between the shaft portion 10C of the vibrator shaft 10 and the second cover 27. The second cover 27 rotatably supports the vibrator shaft 10 via the input bearing 32. Note that the input bearing 32 is not limited to a ball bearing, and various bearings may be used, for example, a roller bearing. Also, without having a dedicated inner ring or outer ring, the inner ring may be integrally formed with the vibrator shaft 10, or the outer ring may be integrally formed with the second cover 27. Further, although both of the input bearings 31 and 32 are sealed bearings with lubricant sealed therein, they do not have to be sealed.

[0022] The main bearing 33 is, for example, a ball bearing having an inner ring 33a, an outer ring 33b, and rolling elements 33c, and is disposed between the internal gear member 23 and the second casing 24. The second casing 24 rotatably supports the internal gear member 23 via the main bearing 33. The main bearing 33 is not limited to a ball bearing, and various bearings can be used. For example, it may be a cross roller bearing, or it may be composed of a plurality of bearings (angular ball bearings, tapered bearings, etc.) spaced apart in the axial direction between the internal gear member 23 and the second casing 24. The main bearing 33 may not have a dedicated inner ring or outer ring, and the inner ring may be integrally formed with the internal gear member 23, or the outer ring may be integrally formed with the second casing 24. The main bearing 33 may be, but is not limited to, a sealed bearing with a lubricant sealed therein.

[0023] Seal portions 41 to 43, which are shaft seal portions for ensuring sealing performance for these bearings, are provided on the axial outside of the input bearings 31, 32 and the main bearing 33 relative to the lubricant containing space S in which the mechanical portions of the flexible mesh gear device 1 are housed.

[0024] The seal portion 41 of the input bearing 31 extends radially inward from the first cover 26 to near the outer circumferential surface of the vibrator shaft 10 (shaft portion 10B) and consists of a wall surface that covers the axially outer side of the input bearing 31, forming a small gap between it and the outer periphery of the shaft portion 10B to hinder the movement of lubricant. The seal portion 42 of the input bearing 32 extends radially inward from the second cover 27 to near the outer circumferential surface of the vibrator shaft 10 (shaft portion 10C) and consists of a wall surface that covers the axially outer side of the input bearing 32, forming a small gap between it and the outer periphery of the shaft portion 10C to hinder the movement of lubricant. The seal portion 43 of the main bearing 33 extends radially inward from the second casing 24 to the vicinity of the outer circumferential surface of the second cover 27, and is made of a wall surface covering the axially outer side of the main bearing 33, forming a small gap between it and the outer periphery of the second cover 27 to inhibit the movement of lubricant. In addition, the inner side (main bearing 33 side) of the seal portion 43 has a protrusion that protrudes radially outward from the second cover 27. The seal portion 43 and the protrusion form a labyrinth structure.

[0025] [Materials of each component] In this embodiment, the materials of the respective members are configured as follows. The vibration exciter shaft 10, the external gear 12, and the spacer rings 36, 37 are made of metal materials such as steel. Although not particularly limited, more specifically, the vibration exciter shaft 10 is made of a steel material such as chrome-molybdenum steel. The external gear 12 is made of a steel material such as nickel-chrome-molybdenum steel. The spacer rings 36, 37 are made of a steel material such as high carbon chrome bearing steel.

[0026] The input bearings 31, 32 and the main bearing 33 have inner and outer races and rolling elements made of metal, for example, high carbon chromium bearing steel. Moreover, the vibrator bearing 15 has rolling elements 15A and a cage 15C made of metal, for example, high carbon chromium bearing steel. Moreover, each of the bolts 51 to 54, 57 is made of a metal, for example, a rolled steel material for general construction, a carbon steel wire for cold heading, a carbon steel material for machine construction, or the like.

[0027] The flexible mesh gear device 1 has a "first gear", a "second gear" that meshes with the "first gear", a "connecting member" that is connected to an "external member", a "pathway member" that is arranged in the (heat transfer) path leading to the "first gear" and the "connecting member", and "other members" that are members other than the "first gear", "second gear", "connecting member" and "pathway member" and are made of resin. One of the features of the "first gear", "connecting member" and "pathway member" is that they are made of resin with a higher thermal conductivity than the "other members".

[0028] Another feature of the flexible mesh gear device 1 is that it has an "output member" that is connected to the "driven member" as the "other member", the "output member" is disposed between the "driven member" and any one of the "first gear", "connecting member" and "path member", and the "driven member" is connected to any one of the "first gear", "connecting member" and "path member" by a metal bolt that passes through the "output member".

[0029] In the flexible mesh gear device 1, the "first gear" corresponds to the first internal gear 22g and the second internal gear 23g, and the "second gear" that meshes with the "first gear" corresponds to the external gear 12. The "external member" corresponds to the external member 55, and the "connecting member" connected to the "external member" corresponds to the first casing 22.

[0030] When the first internal gear 22g is defined as the "first gear," the first casing 22 corresponds to a "path member" that is arranged on the path leading to the "first gear" and the "connecting member." That is, for the path of heat transfer of the first internal gear 22g, the connecting portion of the first casing 22 with the external member 55 (the radially outer portion of the first casing 22) is the "connecting member," and the portion of the first casing 22 between the peripheral portion of the first internal gear 22g and the vicinity of the connecting portion with the external member 55 is the "path member." In other words, for the path of heat transfer of the first internal gear 22g, the "first gear," "path member," and "connecting member" are integrally configured.

[0031] When the second internal gear 23g is defined as the "first gear", the internal gear member 23 corresponds to a "path member" that is arranged on the path leading to the "first gear" and the "connecting member". That is, for the heat transfer path of the second internal gear 23g, the first casing 22 is a "connecting member," and the portion of the internal gear member 23 other than the second internal gear 23g is a "path member." In other words, for the heat transfer path of the second internal gear 23g, the "first gear" and the "path member" are integrally configured. In the case of the heat transfer path of the second internal gear 23g, a metallic main bearing 33 is provided between the internal gear member 23 as the "path member" and the first casing 22 as the "connecting member", and the main bearing 33 constitutes a part of the heat transfer path. More specifically, an inner ring 33a of the main bearing 33 abuts against the internal gear member 23 in the radial and axial directions, and an outer ring 33b of the main bearing 33 abuts against the first casing 22 in the axial direction, thereby forming the heat transfer path.

[0032] The "other members" that are members other than the "first gear", "second gear", "connecting member" and "path member" and are made of resin include the second casing 24, the first cover 26 and the second cover 27. In other words, the "other parts" are parts excluding parts corresponding to any of the above-mentioned "first gear," "second gear," "connecting part," and "path part," as well as metal parts such as the vibrator shaft 10, the external gear 12, the spacer rings 36, 37, the input bearings 31, 32, the main bearing 33, the vibrator bearing 15, and the bolts 51-54, 57, etc., already mentioned.

[0033] In this flexible meshing gear device 1, the second casing 24, first cover 26 and second cover 27, which correspond to the "other parts", are made of resin, and the first internal gear 22g, second internal gear 23g, first casing 22 and internal gear member 23, which correspond to the "first gear", "connecting member" and "path member", are made of resin having a higher thermal conductivity than the respective parts corresponding to the "other parts". In the following description, the term "high thermal conductive resin member" will be used to collectively refer to members made of resin with a higher thermal conductivity than the "other members", such as the "first gear", "connecting member" and "path member", and the term "low thermal conductive resin member" will be used to collectively refer to members made of resin with a lower thermal conductivity that falls under the "other members". In Fig. 1, the members corresponding to the "low thermal conductive resin member" are hatched with the same pattern, and the members corresponding to the "high thermal conductive resin member" are hatched with a different pattern, so that they can be easily distinguished from each other. This is also the case with Fig. 2, which will be described later.

[0034] For all the members corresponding to the above-mentioned "low thermal conductive resin member", multiple types of resins may be used instead of the same resin. Similarly, for all the members corresponding to the above-mentioned "high thermal conductive resin member", multiple types of resins may be used instead of the same resin. However, all of the resins used in the "high thermal conductive resin member" have a higher thermal conductivity than all of the resins used in the "low thermal conductive resin member".

[0035] In the present embodiment, the resin used for the "low thermal conductive resin member" is one in which reinforcing fibers are contained in the resin base material. Note that a resin that does not contain reinforcing fibers may also be used. The base resin is, for example, an engineering plastic (general-purpose engineering plastic) with heat resistance of about 50 to 60°C. Specific examples include polyamide (PA), polycarbonate (PC), polyacetal (POM), modified polyphenylene ether (m-PPE), polybutylene terephthalate (PBT), etc. Heat resistance here does not refer to the temperature at which the shape can be statically maintained, but rather the temperature at which the gear's performance can be maintained, and the same applies to highly thermally conductive resin members. Examples of reinforcing fibers include glass fibers, aramid fibers, polyethylene fibers, Zylon fibers, boron fibers, etc. General-purpose engineering plastics containing these fibers (for example, polyacetal containing glass fibers) have a thermal conductivity of less than 0.3 W / m°C.

[0036] In the present embodiment, the resin used for the "high thermal conductive resin member" is one in which reinforcing fibers are contained in the resin base material. Note that a resin that does not contain reinforcing fibers may also be used. The base resin is preferably a resin with a heat resistance of 70° C. or more, for example, a super engineering plastic (special engineering plastic) with a heat resistance of 100° C. or more is used. Specific examples include polyether ether ketone (PEEK), polyamide imide (PAI), polyphenylene sulfide (PPS), polytetrafluoroethylene (PTFE), aromatic polyamide (PPA), liquid crystal polymer (LCP), polysulfone (PSU), polyether sulfone (PES), polyether imide (PEI), polyarylate (PAR), thermoplastic polyimide (TPI), etc. The reinforcing fibers may be fibers having higher thermal conductivity than the reinforcing fibers of the "low thermal conductive resin member", such as carbon fibers. The thermal conductivity of the high thermal conductive resin member is preferably 0.5 W / m°C or higher, and in the case of a resin containing carbon fibers in a super engineering plastic (e.g., polyether ether ketone), the thermal conductivity is 0.95 W / m°C.

[0037] In the flexure mesh gear device 1, the "driven member" corresponds to the driven member 56, and the "output member" connected to the "driven member" corresponds to the second cover 27. The second cover 27 is disposed between the internal gear member 23, which serves as the "path member", and the driven member 56. The driven member 56 is connected to the internal gear member 23, which is the "path member", by a metal bolt 54 passing through the second cover 27, which serves as the "output member".

[0038] [Operation description] In the flexible mesh gear device 1 configured as above, when the vibration exciter shaft 10 is rotated by a driving source such as a motor, the motion of the vibration exciter 10A is transmitted to the external gear 12. At this time, the external gear 12 is restricted to a shape that conforms to the outer circumferential surface of the vibration exciter 10A, and is bent into an elliptical shape having a major axis portion and a minor axis portion when viewed from the axial direction. Furthermore, the external gear 12 is meshed with the fixed first internal gear 22g at the major axis portion. Therefore, the external gear 12 does not rotate at the same rotation speed as the vibration exciter 10A, and the vibration exciter 10A rotates relatively inside the external gear 12. Then, with this relative rotation, the external gear 12 is flexibly deformed so that the major axis position and the minor axis position move in the circumferential direction. The period of this deformation is proportional to the rotation period of the vibration exciter shaft 10.

[0039] When the external gear 12 flexes and deforms, the position of its major axis moves, and the meshing position between the external gear 12 and the first internal gear 22g changes in the rotation direction. Here, for example, if the number of teeth of the external gear 12 is 100 and the number of teeth of the first internal gear 22g is 102, the meshing teeth of the external gear 12 and the first internal gear 22g shift every time the meshing position rotates around one revolution. For example, when the external member 55 is fixed, the first internal gear 22g is fixed, so the external gear 12 rotates (spins on its axis). With the above number of teeth, the rotational motion of the vibration exciter shaft 10 is decelerated at a reduction ratio of 100:2 and transmitted to the external gear 12.

[0040] Meanwhile, since the external gear 12 also meshes with the second internal gear 23g, the meshing position between the external gear 12 and the second internal gear 23g also changes in the rotational direction due to the rotation of the vibration exciter shaft 10. If the number of teeth of the second internal gear 23g and the number of teeth of the external gear 12 are the same, the external gear 12 and the second internal gear 23g do not rotate relative to each other, and the rotational motion of the external gear 12 is transmitted to the second internal gear 23g at a reduction ratio of 1:1. As a result, the rotational motion of the vibration exciter shaft 10 is decelerated at a reduction ratio of 100:2 and transmitted to the internal gear member 23 and the second cover 27, and this rotational motion is output to the driven member 56.

[0041] During this operation, the first internal gear 22g and the second internal gear 23g mesh with the external gear 12, respectively, and generate heat due to friction. A part of the heat generated at this meshing portion is transferred to the external gear 12 made of metal with high thermal conductivity, the vibrator bearing 15, and the vibrator shaft 10, and is dissipated. Furthermore, the heat generated in the first internal gear 22g is transferred to the external member 55 through the first casing 22 and is dissipated. Moreover, the heat generated in the second internal gear 23g is transmitted to the internal gear member 23, and further transmitted from the first casing 22 to the external member 55 via the main bearing 33, and is dissipated. Moreover, the heat generated in the second internal gear 23g is also transmitted to the driven member 56 through the bolts 54 and is dissipated.

[0042] [Technical effect of the present embodiment] The flexible mesh gear device 1 is made of resin, with the second casing 24, first cover 26 and second cover 27 corresponding to the "other parts", and the first internal gear 22g, second internal gear 23g, first casing 22 and internal gear member 23 corresponding to the "first gear", "connecting member" and "path member". Therefore, it is possible to reduce the number of metal members in the flexible mesh gear device 1, thereby realizing a reduction in weight.

[0043] Furthermore, in the flexible mesh gear device 1, the external gear 12 (the vibrator bearing 15 and the vibrator shaft 10) are made of metal, so heat generated in the meshing portion can be dissipated via these metal members. Furthermore, in the flexible meshing gear device 1, each component that serves as the heat transfer path from the first internal gear 22g and the second internal gear 23g to the external member 55 and the driven member 56 is made of a resin material that is a highly thermal conductive resin component, so that heat is efficiently dissipated to the external member 55, making it possible to effectively suppress the temperature rise of the device.

[0044] Furthermore, in the flexure mesh gear device 1, not all resin members are made of highly heat-conductive resin, but low-heat-conductive resin members are used for the other members that do not form a heat transfer path. The resin base material used for low thermal conductive resin members is generally an inexpensive resin, such as general-purpose engineering plastics, while the resin base material used for high thermal conductive resin members is generally an expensive resin with special functions and characteristics, such as super engineering plastics.Furthermore, the fibers with low thermal conductivity (e.g., glass fibers) contained in low thermal conductive resin members are less expensive than the fibers with high thermal conductivity (e.g., carbon fibers) contained in high thermal conductive resin members. Therefore, as described above, by using a resin with high thermal conductivity only for the components that serve as the heat transfer path from the heat generation point in the flexural meshing gear device 1 to the external component 55 capable of dissipating heat, it is possible to reduce the weight of the flexural meshing gear device 1 while also reducing manufacturing costs.

[0045] Furthermore, the highly thermally conductive resin member uses fibers contained in the resin serving as the base material that have a higher thermal conductivity than the low thermally conductive resin member. Therefore, the highly thermally conductive resin member is capable of efficiently transferring heat while maintaining high component strength and realizing a lightweight structure, thereby enabling effective heat dissipation.

[0046] Furthermore, the high thermal conductive resin member uses, as its base material, a resin with higher heat resistance than the base material of the low thermal conductive resin member. Therefore, even if the first internal gear 22g and the second internal gear 23g generate heat during operation of the flexure meshing gear device 1, wear, deterioration, and deformation are suppressed due to the high heat resistance, and high operational accuracy can be maintained. Furthermore, the high heat resistance of each component through which heat is transferred makes it possible to suppress deterioration and deformation.

[0047] In addition, the flexible mesh gear device 1 has the first internal gear 22g and the second internal gear 23g as first gears, and the external gear 12 as a second gear. When an internal gear and an external gear mesh, the external gear has a larger overall size and therefore a larger volume. Therefore, by making the first internal gear 22g and the second internal gear 23g the first gears and making them from resin, it is possible to effectively reduce the weight.

[0048] Furthermore, in the flexible mesh gear device 1, a metal main bearing 33 is arranged between the internal gear member 23 and the first casing 22, which form the heat transfer path, so that efficient heat conduction is achieved through the main bearing 33, making it possible to efficiently dissipate heat.

[0049] In addition, since the first casing 22 as a connecting member and the external member 55 are connected by metal bolts 53, heat is efficiently transferred not only through the contact surfaces of these members but also through the bolts 53, making it possible to efficiently dissipate heat.

[0050] In addition, the flexible mesh gear device 1 is provided with a second cover 27 as an output member connected to the driven member 56, and the driven member 56 is connected to the internal gear member 23 by a metal bolt 54 passing through the second cover 27. Therefore, even if the second cover 27, which is a low thermal conductive resin material, is interposed in the middle of the heat transfer path, the bolt 54 ensures a heat transfer path from the second internal gear 23g to the driven member 56, making it possible to dissipate heat efficiently.

[0051] [Second embodiment] A second embodiment of the present invention will be described in detail with reference to the drawings. Fig. 2 is a cross-sectional view showing a flexible mesh gear device 1 according to the second embodiment. Since most of the configuration of the flexible mesh gear device 1 of the second embodiment is the same as that of the flexible mesh gear device 1 of the first embodiment, only these differences will be mainly described.

[0052] In the first embodiment, the flexible mesh gear device 1 is configured such that the first casing 22 and the second casing 24 are connected to the external member 55 in a co-tightened state by bolts 53, with the external member 55 in direct contact with the first casing 22. In contrast, in the second embodiment, the flexible mesh gear device 1 is configured such that the first casing 22 and the second casing 24 are connected to the external member 55 in a co-tightened state by bolts 53, with the external member 55 in direct contact with the second casing 24.

[0053] Accordingly, in the first embodiment, the second casing 24 corresponds to "other members" (low thermal conductive resin member), but in the second embodiment, the second casing 24 corresponds to "connecting member" that serves as a path for heat transfer between the first internal gear 22g and the second internal gear 23g, and is made of resin as a highly thermal conductive resin member. The base material of the resin as the highly thermal conductive resin member and the fine particles contained therein are as exemplified in the first embodiment.

[0054] In this second embodiment of the flexible mesh gear device 1, when the first internal gear 22g is the "first gear," the first casing 22 serves as the "path member" and the second casing 24 serves as the "connecting member," forming a heat transfer path, and heat is dissipated from the external member 55. Furthermore, when the second internal gear 23g is the "first gear", the internal gear member 23 constitutes a heat transfer path as a "path member" and the second casing 24 constitutes a "connecting member". Heat is transferred between the internal gear member 23 and the second casing 24 via the main bearing 33. Thus, heat is dissipated from the external member 55.

[0055] In this way, when the connecting member used for connection to the external member 55 is changed, the member corresponding to the high thermal conductivity resin member changes; however, even in the case of the flexible mesh gear device 1 of the second embodiment, it is possible to obtain the same technical effect as the flexible mesh gear device 1 of the first embodiment.

[0056] [others] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments. For example, in the above-mentioned flexible mesh gear device 1, the member corresponding to the "first gear" and the member corresponding to the "path member" may be integrally formed, or may be formed as separate members. The same applies to the member corresponding to the "path member" and the member corresponding to the "connecting member".

[0057] In addition, in each of the above embodiments, the first internal gear 22g and the second internal gear 23g are each defined as the "first gear" and a heat transfer path is configured for each of them, but only one of the first internal gear 22g and the second internal gear 23g may be defined as the "first gear" and a heat transfer path may be configured for only that one gear. The heat transfer path may also be configured with the external gear 12 as the "first gear". In that case, it is preferable that the external gear 12 is configured to transfer heat to the "path member" via a metal bearing (for example, the vibration exciter bearing 15).

[0058] Also, some or all of the vibrator shaft 10, external gear 12, spacer rings 36, 37, input bearings 31, 32, main bearing 33, vibrator bearing 15, and bolts 51 to 54, 57, which are exemplified as metal members, may be made of resin. In that case, it is preferable that the members in the heat transfer path are made of the resin matrix and fibers exemplified in the first embodiment as highly thermally conductive resin members.

[0059] In addition, in each of the above embodiments, a configuration has been exemplified in which the driven member 56 is connected to the internal gear member 23 as a path member by a metal bolt 54, but this is not limited to the above, and the driven member 56 may also be connected to a member corresponding to the "first gear" or the "connecting member" by a bolt.

[0060] In addition, in each of the above embodiments, a so-called cylindrical type flexure mesh gear device has been shown as the flexure mesh gear device 1. However, the present invention is not limited to this and can also be applied to, for example, a so-called cup type or top hat type flexure mesh gear device.

[0061] Furthermore, the present invention is not limited to flexible meshing gear devices, but can be applied to various gear devices, for example, to gear devices that constitute a center crank type or distribution type eccentric oscillating reduction gear device, or to simple planetary gear devices, and can also be applied to parallel axis gear devices, or orthogonal gear devices, etc. In addition, the details shown in the above embodiment can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0062] 1. Flexible mesh gear system (gear system) 12 External gear (second gear) 15 Vibrator bearing 22 First casing (connecting member, path member) 22g 1st internal gear (1st gear) 23 Internal gear component (path component) 23g 2nd internal gear (1st gear) 24 Second casing (connecting member, other members) 26 First cover (other parts) 27 Second cover (other parts, output parts) 31,32 Input bearing 33 Main bearing 51~54,57 Volts 55 External parts 56 Driven member

Claims

1. A gear device including a first gear and a second gear meshing with the first gear, At least the first gear is made of resin, a connecting member connected to an external member, a path member arranged on a path from the first gear to the connecting member, and another member other than the first gear, the second gear, the connecting member, and the path member and made of resin, the first gear, the connecting member, and the path member are made of a resin having a higher thermal conductivity than the other members, The other member includes at least a cover that supports an input bearing, A gear device in which a heat transfer path from the first gear to the connecting member is formed by the path member without passing through a low thermal conductive resin member made of a low thermal conductive resin having a lower thermal conductivity than a resin having a higher thermal conductivity than the other members.

2. the connecting member includes a casing that covers the radial outside of the first gear and the second gear, The casing is connected to the external member.

2. The gear arrangement of claim 1.

3. The casing includes a first casing connected to the cover and a second casing supporting a main bearing, The first casing, the second casing, and the external member are connected together in a fastened state by bolts.

3. The gear arrangement of claim 2.

4. The cover includes a first cover connected to the connecting member and a second cover, The other member includes at least one of the first cover and the second cover. A gear arrangement according to any one of claims 1 to 3.

5. The gear device is a flexible mesh gear device, The first cover covers an outer periphery of one end of the vibration exciter shaft, The second cover covers an outer periphery of the other end of the vibration exciter shaft.

5. The gear arrangement of claim 4.

6. The first gear is an internal gear, The second gear is an external gear. A gear arrangement according to any one of claims 1 to 5.

7. The fibers contained in the resin of the first gear, the connecting member, and the path member have a higher thermal conductivity than the fibers contained in the resin of the other members. A gear arrangement according to any one of claims 1 to 6.

8. The resin base material of the first gear, the connecting member, and the path member has higher heat resistance than the resin base material of the other members. A gear arrangement according to any one of claims 1 to 7.

9. A metal bearing is disposed between the first gear, the connecting member, and the path member. A gear arrangement according to any one of claims 1 to 8.

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