CN115539597A

CN115539597A - Flexible gear, wave speed reducer and robot

Info

Publication number: CN115539597A
Application number: CN202210747218.8A
Authority: CN
Inventors: 前口裕二; 杉下健治; 松下勇树
Original assignee: Nidec Shimpo Corp
Current assignee: Nidec Drive Technology Corp
Priority date: 2021-06-30
Filing date: 2022-06-29
Publication date: 2022-12-30
Also published as: JP2023006337A

Abstract

The invention provides a flexible gear, a wave speed reducer and a robot. The flexible gear (40) has: a flexible body (41) extending in the axial direction around the central axis (9); and a 1 st oil-containing member (44) containing a lubricating oil. The body (41) has: a 1 st body (411) having a cylindrical shape extending in an axial direction; and a 2 nd body part (412) which is disposed on one side in the axial direction of the 1 st body part (411) and has a cylindrical shape extending in the axial direction. The radially inner surface of the 1 st oil-retaining member (44) is in contact with the radially outer surface of the 1 st body (411). The 2 nd barrel (412) has a plurality of external teeth (400) projecting radially outward from the radially outer surface.

Description

Flexible gear, wave speed reducer and robot

Technical Field

The invention relates to a flexible gear, a wave speed reducer and a robot.

Background

Conventionally, there has been known a wave gear device mainly used for a speed reducer (japanese unexamined patent publication No. 2006-132726).

In a conventional gear device and a harmonic type reduction gear, in order to improve wear resistance of tooth surfaces of external teeth of a flexible spline (flexible gear) and tooth surfaces of internal teeth of a rigid spline (internal gear) that mesh with each other, the tooth surfaces of the external teeth of the flexible spline and the tooth surfaces of the internal teeth of the rigid spline are formed of a specific type of resin.

However, when a flexible gear is molded with a resin, there is a problem that molding accuracy is low as compared with a flexible gear made of a metal. In addition, if the material of the flexible gear and the internal gear is changed, a new manufacturing apparatus needs to be introduced. Therefore, it is preferable to lubricate the external teeth of the flexible gear without changing the material of the conventional flexible gear and internal gear, thereby improving the wear resistance of the external teeth of the flexible gear.

Disclosure of Invention

The purpose of the present invention is to provide a technique capable of lubricating the external teeth of a flexible gear.

An exemplary embodiment of the present application provides a flexible gear having: a flexible body extending in an axial direction around a central axis; and a 1 st oil-containing member containing a lubricating oil. The body has: a 1 st body part having a cylindrical shape extending in an axial direction; and a 2 nd body part which is in a cylindrical shape extending in the axial direction and is disposed on one side in the axial direction of the 1 st body part. The radially inner side surface of the 1 st oil-containing member is in contact with the radially outer side surface of the 1 st body. The 2 nd body portion has a plurality of external teeth projecting radially outward from a radially outer side surface.

A wave speed reducer according to an exemplary embodiment of the present invention includes: the flexible gear described above; a wave generator rotatable about the central axis; a flexible bearing that connects a radially outer surface of the wave generator and a radially inner surface of the 2 nd body so as to be relatively rotatable; and an internal gear disposed radially outward of the 2 nd body portion and having a plurality of internal teeth arranged in a circumferential direction.

A robot according to an exemplary embodiment of the present invention includes: the above-described wave speed reducer; a motor that provides rotational power to the wave generator; and an output portion rotatable with the flexible gear.

According to the flexible gear of the exemplary embodiment of the present application, when the flexible gear is flexibly deformed, the lubricating oil oozes out from the 1 st oil-impregnated member, and the external teeth are lubricated. In addition, according to the wave speed reducer and the robot of the exemplary embodiment of the present invention, the wave speed reducer and the robot can be driven for a long time.

The above and other features, elements, steps, features and advantages of the present invention will be more clearly understood from the following detailed description of preferred embodiments of the present invention with reference to the accompanying drawings.

Drawings

Fig. 1 is a longitudinal sectional view of a wave speed reducer of embodiment 1.

Fig. 2 is a cross-sectional view of the wave speed reducer of embodiment 1.

Fig. 3 is a partial longitudinal sectional view of the wave speed reducer of embodiment 1.

Fig. 4 is a partial longitudinal sectional view of the wave speed reducer of embodiment 1.

Fig. 5 is a perspective view of the 1 st oil-impregnated member of the 1 st embodiment.

Fig. 6 is a perspective view of the flexible bearing according to embodiment 1.

Fig. 7 is a perspective view of the 2 nd oil-impregnated member of embodiment 1.

Fig. 8 is a perspective view of the 1 st oil-impregnated member of the modification.

Fig. 9 is a partial plan view of the 1 st oil-impregnated member according to the modification.

Fig. 10 is a perspective view of a flexible bearing according to a modification.

Fig. 11 is a perspective view of the 2 nd oil-impregnated member of the modification.

Fig. 12 is a perspective view of a 3 rd oil-retaining member of a modification.

Fig. 13 is a perspective view of a robot with a wave-motion reducer.

Detailed Description

Hereinafter, exemplary embodiments of the present application will be described with reference to the drawings. In the present application, a direction parallel to the central axis of the wave speed reducer is referred to as an "axial direction", a direction perpendicular to the central axis of the wave speed reducer is referred to as a "radial direction", and a direction along an arc centered on the central axis of the wave speed reducer is referred to as a "circumferential direction". However, the "parallel direction" also includes a substantially parallel direction. The "vertical direction" also includes a substantially vertical direction.

< 1. Embodiment 1 >

< 1-1. Integral Structure of wave retarder

Fig. 1 is a longitudinal sectional view of a wave speed reducer 1 of embodiment 1. In addition, FIG. 1 is A sectional view of the section A-O-A' shown in FIG. 2. Fig. 2 is a cross-sectional view of the wave speed reducer 1. In addition, fig. 2 is a sectional view of the section B-B of fig. 1.

The wave speed reducer 1 is a device that transmits a rotational motion of a 1 st rotational speed obtained from a motor to a subsequent stage while shifting (decelerating) the rotational motion to a 2 nd rotational speed lower than the 1 st rotational speed. The wave speed reducer 1 is used by being assembled to a joint of a small robot together with a motor, for example. However, the wave speed reducer of the present invention may be used for other devices such as an auxiliary set, a turntable, an index plate of a machine tool, a wheelchair, and an automated guided vehicle.

The wave speed reducer 1 has a wave generator 20, a flexible bearing 30, a flexible gear 40, and an internal gear 50. As shown in fig. 1 and 2, the wave speed reducer 1 of the present embodiment includes an input member 10, a wave generator 20, a flexible bearing 30, a flexible gear 40, an internal gear 50, a 1 st housing 60, a 2 nd housing 70, and a roller bearing 80.

The input member 10 is rotated at the 1 st rotation speed before the speed reduction. The input member 10 of the present embodiment is cylindrical and extends along the center axis 9. The input member 10 may be a motor shaft, or may be a member connected to a motor, not shown, directly or via a power transmission mechanism such as a gear. When the motor is driven, the input member 10 rotates around the center axis 9 at the 1 st rotation speed.

The wave generator 20 is a mechanism that generates periodic flexural deformation of a 2 nd body portion 412, which will be described later, of the flexible gear 40. The wave generator 20 is rotatable about the central axis 9. When the motor is driven, the wave generator 20 is also rotated together with the input member 10 at the 1 st rotation speed about the central axis 9. The wave generator 20 of the present embodiment is an elliptical cam. The input member 10 and the wave generator 20 may be formed of a single member as shown in fig. 1, or may be separate members.

The flexible bearing 30 is disposed between the wave generator 20 and the flexible gear 40. The flexible bearing 30 connects the radially outer side surface of the wave generator 20 and the radially inner side surface of the 2 nd body portion 412 so as to be able to rotate relative to each other. The flexible bearing 30 is capable of displacing in the radial direction in accordance with the rotation of the wave generator 20.

The flexible bearing 30 has a flexible inner race 31, a flexible outer race 32, and a plurality of balls 33. The flexible bearing 30 is a ball bearing. The flexible inner ring 31 is fixed to a radially outer side surface of the wave generator 20. A radially inner side surface of the flexible inner ring 31 is fixed to a radially outer side surface of the wave generator 20. The radially outer side surface of the flexible outer race 32 is fixed to the radially inner side surface of the 2 nd body portion 412 of the flexible gear 40. The plurality of balls 33 are rotatably disposed between the flexible inner race 31 and the flexible outer race 32. The detailed structure of the flexible bearing 30 will be described later.

The flexible gear 40 is a thin ring-shaped gear that can be deformed by bending. In the present embodiment, the flexible gear 40 has a substantially elliptical shape in a cross-sectional view perpendicular to the center axis 9. The flexible gear 40 is supported to be rotatable about the central axis 9. The flexible gear 40 of the present embodiment includes a body portion 41, a flange portion 42, a fixing portion 43, and a 1 st oil-containing member 44. The body 41 has flexibility and extends in the axial direction around the central axis 9. The 1 st oil-containing member 44 contains lubricating oil. That is, the flexible gear 40 includes a flexible body portion 41 extending in the axial direction about the center axis 9 and a 1 st oil-containing member 44 containing lubricating oil. The 1 st oil-containing member 44 will be described later.

The body 41 extends cylindrically in the axial direction around the center axis 9. The body 41 has a 1 st body 411 and a 2 nd body 412. The 1 st body portion 411 and the 2 nd body portion 412 each have a cylindrical shape extending in the axial direction. The 2 nd body portion 412 is disposed on one side in the axial direction of the 1 st body portion 411. The axial side is oriented from the 1 st housing 60 toward the 2 nd housing 70. In the drawings, one axial side is denoted by D1, and the other axial side is denoted by D2.

The compliant gear 40 has a flange portion 42. The flange 42 is an annular portion extending radially outward from the other axial end of the body 41. The fixing portion 43 is a portion extending further radially outward from the radially outer end of the flange portion 42. The thickness of the fixing portion 43 in the axial direction is larger than the thickness of the flange portion 42 in the axial direction. The fixing portion 43 is fixed to the 1 st housing 60 and an outer ring 82 of the roller bearing 80, which will be described later.

The body 41 is flexible and therefore can be deformed in the radial direction. In particular, the 2 nd body portion 412 is a distal end portion of the body portion 41 and a free end, and therefore can be displaced more largely in the radial direction than the 1 st body portion 411. On the other hand, the 1 st body 411 is less likely to be deformed in the radial direction as it approaches the vicinity of the other axial end of the body 41. In addition, with the modification of the body portion 41, the flange portion 42 is slightly flexurally deformed in the axial direction, but the fixing portion 43 is hardly deformed.

As shown in fig. 1 and 2, the compliant gear 40 has a plurality of external teeth 400. Specifically, the 2 nd body portion 412 has a plurality of external teeth 400 protruding radially outward from the radially outer surface. In addition, the plurality of outer teeth 400 are arranged at a constant pitch in the circumferential direction.

The 2 nd body portion 412 is pressed radially outward via the flexible outer ring 32 of the flexible bearing 30 at 2 locations at the same circumferential position as the circumferential position of the major axis of the elliptical wave generator 20. Thereby, the 2 nd body portion 412 is flexurally deformed into an elliptical shape. As a result, the external teeth 400 provided in the 2 nd body part 412 mesh with the internal teeth 500 of the internal gear 50 described later at 2 locations corresponding to the major axis of the ellipse in the circumferential direction. Hereinafter, the circumferential position at which the outer teeth 400 mesh with the inner teeth 500 is referred to as "meshing position".

The internal gear 50 has a substantially annular shape centered on the central axis 9. The internal gear 50 is fixed to the 2 nd housing 70 by, for example, screws. The rigidity of the internal gear 50 is much higher than that of the body portion 41 of the flexible gear 40. Therefore, the internal gear 50 can be substantially regarded as a rigid body. The internal gear 50 has a plurality of internal teeth 500. The plurality of internal teeth 500 protrude radially inward from the radially inner side surface of the internal gear 50. In addition, the plurality of internal teeth 500 are arranged at a constant pitch in the circumferential direction.

The internal gear 50 is disposed radially outward of the 2 nd body portion 412. That is, the internal gear 50 is disposed radially outward of the 2 nd body portion 412 and has a plurality of internal teeth 500 arranged in the circumferential direction.

The flexible gear 40 has a slightly different number of external teeth 400 than the internal teeth 500 of the internal gear 50.

The wave speed reducer 1 has a housing that is disposed on the other axial side of the flexible gear 40 and fixes the flexible gear 40. The 1 st case 60 is an example of the case. The 1 st housing 60 is disposed on the other axial side of the flexible gear 40. The 1 st housing 60 has a cylindrical portion 61 and a hood portion 62.

The cylindrical portion 61 is a substantially cylindrical portion extending along the central axis 9. One axial end of the cylindrical portion 61 is disposed radially inward of the 1 st body 411 of the flexible gear 40. The other axial end of the cylindrical portion 61 is disposed on the other axial side of the flexible gear 40. A bearing 11 is disposed between the radially inner surface of the cylindrical portion 61 and the radially outer surface of the input member 10. Thereby, the input member 10 can rotate with respect to the 1 st housing 60.

The cover portion 62 extends radially outward from the other axial end of the cylindrical portion 61. The cover 62 is an annular portion surrounding the central axis 9. The cover portion 62 overlaps the entirety of the flexible gear 40 when viewed from the other axial side. The flexible gear 40 is fixed to the 1 st housing 60. Specifically, the fixing portion 43 of the flexible gear 40 is sandwiched between the cover portion 62 of the 1 st housing 60 and the outer ring 82, and is fixed by a fastening member such as a screw.

The 2 nd housing 70 is disposed on one axial side of the internal gear 50. The 2 nd housing 70 has a ring shape centered on the central axis 9. The 2 nd housing 70 overlaps the entire internal gear 50 when viewed from one axial side. The internal gear 50 is fixed to the 2 nd housing 70. Specifically, the internal gear 50 is sandwiched between the 2 nd housing 70 and an inner ring 81 of a roller bearing 80 described later, and is fixed by a fastening member such as a screw. Further, a bearing 12 is disposed between the radially inner surface of the 2 nd housing 70 and the radially outer surface of the input member 10. Thereby, the input member 10 is supported rotatably with respect to the 2 nd housing 70.

The roller bearing 80 is disposed radially outward of the 1 st body 411. The roller bearing 80 has an inner ring 81, an outer ring 82, and a plurality of rolling elements 83 sandwiched between the inner ring 81 and the outer ring 82. As described above, the inner race 81 of the roller bearing 80 is fixed to the internal gear 50. In more detail, the inner race 81 of the roller bearing 80 is fixed to the internal gear 50 and the No. 2 housing 70. The outer race 82 of the roller bearing 80 is fixed to the compliant gear 40. More specifically, the outer race 82 of the roller bearing 80 is fixed to the fixed portion 43 of the flexible gear 40 and the cover portion 62 of the 1 st housing 60. Thereby, the roller bearing 80 connects the flexible gear 40 and the 1 st housing 60, and the internal gear 50 and the 2 nd housing 70 in a relatively rotatable manner.

In the present embodiment, the 1 st housing 60 is an output member of the wave speed reducer 1. When the 1 st case 60 is used as the output member, the 2 nd case 70 is fixed to a housing of a device in which the wave speed reducer 1 is mounted, for example, by screwing. When the wave generator 20 rotates at the 1 st rotational speed, the major axis of the compliant gear 40 also rotates at the 1 st rotational speed. Then, the meshing position of the external teeth 400 and the internal teeth 500 also changes in the circumferential direction at the 1 st rotation speed. In addition, as described above, the number of external teeth 400 of the flexible gear 40 is slightly different from the number of internal teeth 500 of the internal gear 50. Due to the difference in the number of teeth, the meshing position of the external teeth 400 and the internal teeth 500 slightly changes in the circumferential direction every 1 rotation of the wave generator 20. As a result, the flexible gear 40 rotates around the central axis 9 with respect to the internal gear 50 at the 2 nd rotation speed lower than the 1 st rotation speed. Therefore, the rotation motion of the 2 nd rotation speed after the speed reduction is output from the 1 st housing 60 rotating at the same rotation speed as the flexible gear 40. That is, the 1 st housing 60 serves as an output portion that rotates together with the flexible gear 40.

The 2 nd housing 70 may be used as an output member. When the 2 nd case 70 is used as the output member, the 1 st case 60 is fixed to a housing of a device in which the wave speed reducer 1 is mounted, for example, by fastening with screws. In this case, when the wave generator 20 rotates at the 1 st rotation speed, the internal gear 50 rotates with respect to the flexible gear 40 around the central axis 9 at the 2 nd rotation speed lower than the 1 st rotation speed. Therefore, the rotation motion of the 2 nd rotation speed after the speed reduction is output from the 2 nd housing 70 that rotates at the same rotation speed as the internal gear 50.

< 1-2 > about the 1 st oil-containing part

Next, the 1 st oil-retaining member 44 will be described with reference to fig. 1 and fig. 3 to 5. Fig. 3 and 4 are partial longitudinal sectional views of the wave speed reducer 1. Fig. 3 is A cross-sectional view of the O-A section other than the meshing position of the outer teeth 400 and the inner teeth 500. Fig. 4 is A cross-sectional view of the cross section O-A' at the meshing position between the outer teeth 400 and the inner teeth 500. Fig. 5 is a perspective view of the 1 st oil-impregnated member 44.

The 1 st oil-containing member 44 is a member containing lubricating oil. In the present embodiment, the resin molded article forming the 1 st oil-containing member 44 is formed by mixing a resin material and a lubricating oil, injecting the mixture into the interior of a mold, and performing heat treatment. This results in a resin molded article having a plurality of fine cavities therein. Since the lubricating oil is stored in the cavity, an oil-containing member is formed in which the lubricating oil is exuded by external force or surface tension. However, the 1 st oil-containing member may be formed by another manufacturing method.

As shown in fig. 3 and 4, the radially inner side surface of the 1 st oil-containing member 44 is in contact with the radially outer side surface of the 1 st body 411. As shown in fig. 3, the body 41 does not flex radially outward at a position farthest from the meshing position of the outer teeth 400 and the inner teeth 500 in the circumferential direction. Therefore, the 1 st oil-containing member 44 is also hardly deflected, and the lubricating oil is less likely to bleed out.

On the other hand, as shown in fig. 4, at the meshing position of the external teeth 400 and the internal teeth 500 in the circumferential direction, the body 41 flexes radially outward. Thereby, the 1 st oil-impregnated member 44 is pressed radially outward by the body portion 41 and is deflected. Therefore, at the meshing position, the 1 st oil-containing member 44 is elastically deformed, so that the lubricating oil that has penetrated inside slightly bleeds out. The oozed lubricating oil lubricates the external teeth 400 along the outer surface of the body portion 41.

Thus, the external teeth 400 are lubricated when the flexible gear 40 is flexibly deformed. Particularly at the meshing position of the outer teeth 400 and the inner teeth 500, the lubricating effect is remarkable. Further, since the wave speed reducer 1 includes the flexible gear 40, the external teeth of the flexible gear 40 can be lubricated, and therefore the wave speed reducer 1 can be driven for a long time.

As shown in fig. 3 and 4, the axial position of the end portion on one axial side of the 1 st oil-impregnated member 44 is the same as the axial position of the end portion on the other axial side of the outer teeth 400. That is, the end portion on one axial side of the 1 st oil-impregnated member 44 is radially opposed to the end portion on the other axial side of the outer teeth 400. This suppresses the 1 st oil-containing member 44 from moving to one side in the axial direction. Further, the lubricating oil of the 1 st oil-impregnated member 44 easily penetrates into the external teeth 400 due to surface tension.

As shown in fig. 5, the 1 st oil-retaining member 44 has a cylindrical shape extending in the axial direction. Thereby, the 1 st oil-retaining member 44 surrounds the radially outer side surface of the 1 st body 411. This allows lubrication of outer teeth 400 over the entire circumference of 2 nd body part 412.

As shown in fig. 3 and 4, the 1 st oil-retaining member 44 has a cylindrical portion 441, a tapered portion 442, and a projecting portion 443.

The cylindrical portion 441 is a substantially cylindrical portion. The tapered portion 442 is disposed at an axial one-side end portion of the 1 st oil-containing member 44. The radially inner surface of the cylindrical portion 441 contacts the radially outer surface of the 1 st body 411. Thereby, the radial position of the 1 st oil-containing member 44 is determined.

The radially inner surface of the tapered portion 442 is inclined radially outward as it goes toward one axial side. As shown in fig. 4, the 1 st body 411 is mainly flexurally deformed near its one axial side end portion at the meshing position of the external teeth 400 and the internal teeth 500. That is, as indicated by the broken line arrow in fig. 4, the 1 st oil-retaining member 44 is most likely to be largely deformed by bending in the vicinity of the one axial end thereof. Therefore, the 1 st oil-retaining member 44 is tapered radially outward in the deformation direction at its one radial end, and excessive lubricant oil oozing out due to large flexible deformation is suppressed.

The projecting portion 443 projects radially outward from the radially outer surface of the cylindrical portion 441 at the other axial end of the cylindrical portion 441. The other axial end of the projection 443 axially contacts one axial surface of the flange 42. That is, the other axial end of the 1 st oil-retaining member 44 is in axial contact with the one axial surface of the flange 42. This suppresses the 1 st oil-retaining member 44 from moving to the other side in the axial direction.

The 1 st oil-retaining member 44 has a projecting portion 443 projecting radially outward from the radially outer side surface. The radially outer end of the projection 443 radially contacts the radially inner surface of the inner ring 81 of the roller bearing 80. Thereby, the 1 st oil retaining member 44 is supported by the 1 st body 411 and the inner ring 81 from both sides in the radial direction. Therefore, the 1 st oil-impregnated member 44 can be more reliably positioned in the radial direction. On the other hand, by using the projection 443 disposed only in a part of the axial direction as a contact portion with the inner ring 81 of the roller bearing 80, the contact area between the inner ring 81 and the 1 st oil-containing member 44 that rotate relative to each other is suppressed, and power loss is suppressed.

The 1 st oil-containing member 44 has one or more notches extending in the axial direction from the end portion on one side in the axial direction or the end portion on the other side in the axial direction. In the present embodiment, as shown in fig. 5, the 1 st oil-retaining member 44 has a plurality of

notches

91 and 92. In the present embodiment, the 1 st oil-retaining member 44 has one 1 st notch 91 and a plurality of 2 nd notches 92. The number of the 2 nd notches 92 is 19.

The 1 st notch 91 cuts the 1 st oil-containing member 44 from one axial end portion to the other axial end portion. That is, the notch includes the 1 st notch 91 formed by cutting the 1 st oil-retaining member 44 from the end on one axial side to the end on the other axial side. By providing only one 1 st notch 91 in the 1 st oil-retaining member 44, the 1 st oil-retaining member 44 can be expanded into a C-shape when viewed in the axial direction. This makes it easy to attach the 1 st oil-impregnated member 44 to the body 41 in the manufacturing process of the flexible gear 40.

The 2 nd notch 92 extends from one axial end of the 1 st oil retaining member 44 to one axial end of the 1 st oil retaining member 44. Specifically, the other axial end of the 2 nd notch 92 is positioned on one axial side of the projection 443.

By providing the

notches

91 and 92 extending in the axial direction in this way, the 1 st oil retaining member 44 is also easily flexibly deformed in accordance with the flexible deformation of the body portion 41 of the flexible gear 40. That is, it is difficult to suppress the flexible deformation of the body 41. Further, the

notches

91 and 92 allow the lubricating oil to smoothly seep out of the 1 st oil-containing member 44.

In the present embodiment, the number of the

notches

91 and 92 is 20 in total. The number of

notches

91, 92 is smaller than the number of outer teeth 400. The plurality of

notches

91 and 92 are arranged at equal intervals in the circumferential direction. This makes the 1 st oil-retaining member 44 uniform in deformation easiness in the circumferential direction. Therefore, the oozing of the lubricating oil from the 1 st oil-impregnated member 44 also becomes more uniform in the circumferential direction.

< 1-3 > about the 2 nd oil-containing part

Next, the 2 nd oil-retaining member 34 will be described with reference to fig. 6 and 7. Fig. 6 is a perspective view of the flexible bearing 30. Fig. 7 is a perspective view of the 2 nd oil-impregnated member 34.

As shown in fig. 6, the flexible bearing 30 of the present embodiment includes a 2 nd oil-retaining member 34 disposed between the flexible inner ring 31 and the flexible outer ring 32. As shown in fig. 7, the 2 nd oil-retaining member 34 is an annular member. In the present embodiment, the 2 nd oil-containing member 34 has a substantially annular shape. The 2 nd oil-containing member 34 is formed by molding a material obtained by mixing a resin material and a lubricating oil, for example, in the same manner as the 1 st oil-containing member 44.

As shown in fig. 7, the 2 nd oil-containing member 34 has a plurality of 1 st recesses 341 and a plurality of 2 nd recesses 342. In the present embodiment, the 2 nd oil-impregnated member 34 further includes a plurality of hollow portions 343. The plurality of 1 st recesses 341 extend from the radially outer side toward the radially inner side. More specifically, the 1 st recessed portions 341 extend radially inward from the radially outer surface of the 2 nd oil retaining member 34. The plurality of 2 nd recesses 342 are directed from the radially inner side toward the radially outer side. More specifically, the 2 nd recessed portions 342 extend radially outward from the radially inner surface of the 2 nd oil-retaining member 34. The hollow sections 343 are respectively provided with balls 33.

The plurality of 1 st recessed portions 341 and the plurality of 2 nd recessed portions 342 are alternately arranged in the circumferential direction. Further, a cavity 343 is disposed between the 1 st recessed portion 341 and the 2 nd recessed portion 342 adjacent in the circumferential direction. In the present embodiment, the number of balls 33 (i.e., the number of hollow portions 343) is 23, and is an odd number. Therefore, the two 1 st recessed portions 341 are located at circumferentially adjacent positions with the hollow portion 343 interposed therebetween.

By disposing the 2 nd oil-containing member 34 in the space between the flexible inner ring 31 and the flexible outer ring 32 in this way, the flexible bearing 30 is lubricated, and the power loss of the flexible bearing 30 is reduced.

Further, the plurality of 1 st recessed portions 341 and the plurality of 2 nd recessed portions 342 are alternately arranged in the circumferential direction, so that the 2 nd oil-containing member 34 is easily expanded and contracted in the radial direction like a wrinkle. Therefore, even when the 2 nd oil-retaining member 34 is disposed between the flexible inner ring 31 and the flexible outer ring 32, it is difficult to suppress deformation of the flexible inner ring 31 and the flexible outer ring 32 in the radial direction.

< 1-4 > about the 3 rd oil-impregnated part

Next, the 3 rd oil-retaining member 35 will be described with reference to fig. 1, 3, and 4. As shown in fig. 1, 3, and 4, the wave reducer 1 of the present embodiment includes the 3 rd oil-containing member 35 disposed radially inward of the body portion 41.

The 3 rd oil-retaining member 35 of the present embodiment is a cylindrical member. The 3 rd oil-containing member 35 is formed by molding a material obtained by mixing a resin material and a lubricating oil, for example, in the same manner as the 1 st oil-containing member 44. The 3 rd oil-retaining member 35 is disposed along the radially inner surface of the body 41. An end surface on one axial side of the 3 rd oil retaining member 35 is in axial contact with an end surface on the other axial side of the flexible bearing 30. This allows the flexible bearing 30 to be lubricated with the lubricating oil that has leaked from the 3 rd oil-impregnated member 35. In addition, the 3 rd oil-impregnated member 35 and the flexible bearing 30 can be positioned in the axial direction.

Further, the other axial end surface of the 3 rd oil-retaining member 35 is in axial contact with the one axial surface of the housing. The 1 st case 60 is an example of the case. That is, the other axial end surface of the 3 rd oil retaining member 35 axially contacts one axial surface of the cylindrical portion 61 of the 1 st housing 60. This can suppress the 3 rd oil-retaining member 35 from shifting to the other axial side.

The 1 st oil-containing member 44 and the 3 rd oil-containing member 35 are arranged at positions overlapping in the radial direction in at least a partial region in the axial direction. That is, a part of the 1 st oil-retaining member 44 and a part of the 3 rd oil-retaining member 35 are opposed to each other in the radial direction via the body 41. This provides a good balance between the radially inner and outer weights of the body 41. Further, by making the axial direction region in which the 1 st oil-impregnated member 44 for lubricating the external teeth 400 is disposed the same as the axial direction region in which the 3 rd oil-impregnated member 35 for lubricating the flexible bearing 30 is disposed, both the external teeth 400 and the flexible bearing 30 can be lubricated without increasing the axial length of the wave reducer 1.

< 2. Variant

The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments.

< 2-1. Variation 1 >)

Fig. 8 is a perspective view of the 1 st oil-impregnated member 44A of a modification. Fig. 9 is a partial plan view of a part of the 1 st oil-impregnated member 44A as viewed from the axial side. The 1 st oil-retaining member 44A can be used in place of the 1 st oil-retaining member 44 in the wave speed reducer 1 of the above embodiment.

The 1 st oil-impregnated member 44A has a plurality of 1 st convex portions 444A protruding radially outward and a plurality of 2 nd convex portions 445A protruding radially inward. The plurality of 1 st convex portions 444A and the plurality of 2 nd convex portions 445A are alternately arranged in the circumferential direction. That is, the 1 st oil-impregnated member 44A has a corrugated shape. This makes it easy to expand or contract the 1 st oil-containing member 44A in the radial direction. Therefore, the 1 st oil-impregnated member 44A is easily attached to the radially outer side surface of the body 41.

As shown in fig. 8 and 9, the radial outer end of the 1 st projection 444A projects in a V shape near the other axial end. This portion becomes the projection 443A. The projection 443A radially contacts the radially inner surface of the inner ring 81.

At an axial position other than the projection 443A, the radial outer end of the 1 st projection 444A is an outer chamfered surface 446A along a cylindrical surface having a smaller diameter than the radial outer end of the projection 443A.

In addition, the radially inner end portion of the 2 nd convex portion 445A includes an inner chamfered surface 447A and a tapered surface 448A. The inner chamfered surface 447A is along a cylindrical surface having a smaller diameter than the outer chamfered surface 446A. The axial region of the 1 st oil-impregnated member 44A including the outer chamfered surface 446A and the inner chamfered surface 447A corresponds to the cylindrical portion 441 in the above embodiment.

The tapered surface 448A is disposed at one axial end of the 1 st oil-retaining member 44A. The tapered surface 448A is inclined axially outward from the axial end of the inner chamfered surface 447A toward the axial side. The axial region of the 1 st oil-impregnated member 44A including the outer chamfered surface 446A and the tapered surface 448A corresponds to the tapered portion 442 in the above embodiment.

The 1 st oil-containing member 44A is corrugated, and therefore easily expands or contracts in the radial direction. Thus, the 1 st oil-containing member 44A can be easily attached to the body 41 without having a cut portion such as the 1 st notch 91 of the 1 st oil-containing member 44 of the above embodiment.

< 2-2. Variation 2 > (ii)

Fig. 10 is a perspective view of a flexible bearing 30B having a 2 nd oil-impregnated member 34B of a modification. Fig. 11 is a perspective view of the 2 nd oil-impregnated member 34B. The flexible bearing 30B can be used in place of the flexible bearing 30 in the wave speed reducer 1 of the above embodiment. The flexible inner race 31, the flexible outer race 32, and the plurality of balls 33 of the flexible bearing 30B shown in fig. 10 are the same as those of the above-described embodiment, and therefore, the description thereof is omitted.

As shown in fig. 11, the 2 nd oil-retaining member 34B has an annular portion 344B and a plurality of columnar portions 345B. The annular portion 344B is an annular portion. The annular portion 344B is disposed on the other axial side of the plurality of balls 33 in a space between the flexible inner race 31 and the flexible outer race 32. The columnar portions 345B extend axially one side from the annular portions 344B. The columnar portions 345B and the balls 33 are alternately arranged in the circumferential direction. Thereby, each columnar portion 345B can lubricate the balls 33 adjacent in the circumferential direction.

In the examples of fig. 10 and 11, the columnar portions 345B each have a quadrangular prism shape, but the shape of the columnar portions 345B is not limited thereto. For example, the circumferential surface of the columnar portion 345B may be a curved surface along the balls 33 adjacent in the circumferential direction.

In the example of fig. 10 and 11, the annular portion 344B is disposed on the other axial side, but the present invention is not limited thereto. The annular portion 344B may be disposed on one axial side.

< 2-3. Variation 3 > (iii)

Fig. 12 is a perspective view of a 3 rd oil-impregnated member 35C of a modification. The 3 rd oil-retaining member 35C can be used in place of the 3 rd oil-retaining member 35 in the wave speed reducer 1 of the above embodiment.

The 3 rd oil-retaining member 35C has a plurality of outer protrusions 351C protruding radially outward and a plurality of inner protrusions 352C protruding radially inward. The plurality of outer convex portions 351C and the plurality of inner convex portions 352C are alternately arranged in the circumferential direction. That is, the 3 rd oil-retaining member 35C has a corrugated shape.

As shown in fig. 12, the radially outer end of the outer convex portion 351C is formed in a V shape which is slightly chamfered. The radially outer end of the outer projection 351C is arranged along the radially inner surface of the body 41. The radially inner end of the inner protrusion 352C is slightly chamfered and has a V-shape.

The 3 rd oil-containing member 35C is easily expanded or contracted in the radial direction because it is corrugated. Thus, the 3 rd oil-retaining member 35C can be easily attached to a predetermined position in the manufacturing process of the wave speed reducer.

< 2-4. Other modifications

In the above-described embodiment, the wave speed reducer 1 includes the 2 nd oil-impregnated member 34 and the 3 rd oil-impregnated member 35 that lubricate the flexible bearing 30 in addition to the 1 st oil-impregnated member 44 that lubricates the external teeth 400, but the present invention is not limited thereto. The 1 st oil-retaining member 44, the 2 nd oil-retaining member 34, and the 3 rd oil-retaining member 35 may be used alone.

< 3. Robot >

Fig. 13 is a perspective view of the robot 100 having the wave speed reducer 1. The robot 100 is, for example, a so-called industrial robot that performs operations such as conveyance, processing, and assembly of components in a production line of industrial products. The robot 100 has a wave speed reducer 1, a motor 13, a base frame 101, and an arm 102 as an output portion.

An output shaft of the motor 13 is fixed to the input member 10 of the wave speed reducer 1. Thereby, the motor 13 supplies the wave generator 1 with rotational power. The arm 102 is fixed to the 1 st housing 60. Thereby, the arm 102 as the output portion can rotate together with the flexible gear 40. When the motor 13 is driven, the input member 10 rotates at the 1 st rotation speed together with the output shaft of the motor 13. Thus, the arm 102 rotates with the 1 st housing 60 and the compliant gear 40 at the 2 nd rotational speed.

As described above, the robot 100 has the wave reducer 1, the motor 13 that supplies rotational power to the wave generator, and the output portion that is rotatable together with the flexible gear 40. As a result, the external teeth 400 can be lubricated by the 1 st oil-impregnated member 44 in the flexible gear 40 of the wave speed reducer 1 mounted on the robot 100. Therefore, the wave speed reducer 1 and the robot can be driven for a long time.

Further, the detailed configuration of the wave speed reducer may be appropriately modified within a range not departing from the gist of the present invention. Further, elements appearing in the above-described embodiments and modifications may be appropriately combined within a range not to cause contradiction.

The present invention can be used for, for example, a flexible gear, a wave speed reducer, and a robot.

Claims

1. A compliant gear, comprising:

a flexible body portion extending in an axial direction with a center axis as a center; and

1 st oil-containing member containing a lubricating oil,

the body has:

a 1 st body part having a cylindrical shape extending in an axial direction; and

a 2 nd body part which is in a cylindrical shape extending in an axial direction and is disposed on one side in the axial direction of the 1 st body part,

it is characterized in that the preparation method is characterized in that,

the radial inner side surface of the 1 st oil-containing member is in contact with the radial outer side surface of the 1 st body,

the 2 nd body portion has a plurality of external teeth projecting radially outward from a radially outer side surface.

2. The compliant gear according to claim 1,

the axial position of the end portion on one axial side of the 1 st oil-impregnated member is the same as the axial position of the end portion on the other axial side of the external teeth.

3. Flexible gear according to claim 1 or 2,

the 1 st oil-retaining member has a cylindrical shape extending in the axial direction,

the 1 st oil-containing member has one or more notches extending in the axial direction from an end portion on one side in the axial direction or an end portion on the other side in the axial direction.

4. Flexible gear according to claim 3,

the notch includes a 1 st notch formed by cutting the 1 st oil-containing member from one end portion in the axial direction to the other end portion in the axial direction.

5. Flexible gear according to claim 3 or 4,

the 1 st oil-containing part has a plurality of the notches,

the notch includes a 2 nd notch extending from an end portion on one axial side of the 1 st oil-retaining member to a position closer to one axial side than an end portion on the other axial side of the 1 st oil-retaining member.

6. Flexible gear according to claim 5,

the number of the notches is smaller than the number of the outer teeth,

the plurality of notches are arranged at equal intervals in the circumferential direction.

7. Flexible gear according to any of claims 1 to 6,

the flexible gear further includes a flange portion extending radially outward from an end portion on the other axial side of the body portion,

an end portion of the 1 st oil-retaining member on the other axial side is in contact with a surface of the flange portion on one axial side in the axial direction.

8. Flexible gear according to any of claims 1 to 7,

the 1 st oil-containing member has:

a plurality of 1 st convex portions, the plurality of 1 st convex portions protruding radially outward; and

a plurality of 2 nd convex parts, the plurality of 2 nd convex parts protruding to the radial inner side,

the plurality of 1 st projections and the plurality of 2 nd projections are alternately arranged in the circumferential direction.

9. A wave speed reducer, characterized in that,

the wave speed reducer has:

the compliant gear of any one of claims 1-8;

a wave generator rotatable about the central axis;

a flexible bearing that connects a radially outer surface of the wave generator and a radially inner surface of the 2 nd body so as to be relatively rotatable; and

and an internal gear disposed radially outward of the 2 nd body and having a plurality of internal teeth arranged in a circumferential direction.

10. A wave speed reducer according to claim 9,

the flexible bearing has:

an inner ring fixed to a radially outer side surface of the wave generator;

an outer ring fixed to a radially inner surface of the 2 nd body;

a plurality of balls rotatably disposed between the inner race and the outer race; and

a 2 nd oil-containing member disposed between the inner ring and the outer ring.

11. The wave retarder of claim 10,

the 2 nd oil-containing member has:

a plurality of 1 st recesses, the plurality of 1 st recesses extending from a radially outer side toward a radially inner side; and

a plurality of 2 nd recessed portions, the plurality of 2 nd recessed portions facing radially outward from a radially inner side,

the plurality of 1 st recessed portions and the plurality of 2 nd recessed portions are alternately arranged in the circumferential direction.

12. A wave retarder according to any of claims 9-11,

the wave speed reducer further includes a cylindrical 3 rd oil-containing member disposed along a radially inner surface of the body,

an end surface of the 3 rd oil-retaining member on one axial side is in axial contact with an end surface of the flexible bearing on the other axial side.

13. A wave speed reducer according to claim 12,

the 3 rd oil-containing member has:

a plurality of outer convex portions protruding radially outward; and

a plurality of inner convex portions protruding radially inward,

the plurality of outer protrusions and the plurality of inner protrusions are alternately arranged in the circumferential direction.

14. A wave speed reducer according to claim 12 or 13,

the 1 st oil-containing member and the 3 rd oil-containing member are arranged at positions overlapping in a radial direction in at least a partial region in an axial direction.

15. A wave retarder according to any of claims 12-14,

the wave speed reducer further has a housing that is disposed on the other axial side of the flexible gear and fixes the flexible gear,

the end surface of the other axial side of the 3 rd oil-containing member is in axial contact with the surface of one axial side of the housing.

16. A wave speed reducer according to any of claims 9-15,

the wave speed reducer further includes a roller bearing disposed radially outward of the 1 st body portion,

the outer ring of the roller bearing is fixed with the flexible gear,

the inner ring of the roller bearing is fixed with the internal gear,

the 1 st oil-containing member has a projecting portion projecting radially outward from a radially outer side surface,

a radially outer end of the protruding portion is in contact with a radially inner surface of the inner ring of the roller bearing in a radial direction.

17. A robot is characterized in that a robot body is provided with a plurality of robots,

the robot comprises:

a wave retarder according to any of claims 9 to 16;

a motor that provides rotational power to the wave generator; and

an output rotatable with the compliant gear.