CN112128343B

CN112128343B - Speed reducer and robot with same

Info

Publication number: CN112128343B
Application number: CN202011182972.9A
Authority: CN
Inventors: 袁成林; 程中甫; 谷甲甲; 张弛; 张皓; 杨繁荣
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2020-10-29
Filing date: 2020-10-29
Publication date: 2021-10-08
Anticipated expiration: 2040-10-29
Also published as: CN112128343A

Abstract

The invention provides a speed reducer and a robot with the same. The reduction gear includes flexbile gear and wave generator, and the wave generator includes: a cam; the bearing is sleeved on the cam, the flexible gear is sleeved on the bearing, and the bearing is positioned between the cam and the flexible gear; wherein, the bearing is a joint bearing or a self-aligning roller bearing. The speed reducer solves the problem that in the prior art, when the axis of the input end and the axis of the speed reducer have an inclined angle, the wave generator cannot realize the aligning function with higher coaxiality requirement.

Description

Speed reducer and robot with same

Technical Field

The invention relates to the field of speed reducers, in particular to a speed reducer and a robot with the same.

Background

The harmonic reducer is mainly composed of a rigid gear, a flexible gear and a wave generator. The flexible gear generates elastic deformation under the action of the wave generator and interacts with the rigid gear, thereby achieving the effect of speed reduction and transmission. Under the action of gear engagement, the harmonic reducer achieves the speed reduction effect and simultaneously improves the bearing torque of the output end.

The wave generator of the self-aligning harmonic reducer is arranged in the inner wall of a flexible gear, and the wave generator can effectively adjust the coaxiality of connection with an input motor by arranging a cross connecting structure, so that the wave generator and a reducer body can be ensured to be matched with each other in a higher coaxiality manner in the installation and use processes. In addition, one side of the wave generator is a cross-shaped pressing block, and the other side of the wave generator is provided with a pressing plate and a spring washer. The two-side structure can axially position the cam of the wave generator.

However, the wave generator described above can only be aligned in a direction perpendicular to its axis, and when there is an inclination angle between the axis of the input end and the axis of the reducer body during installation, the wave generator cannot achieve the alignment function required for high coaxiality.

In addition, the wave generator is provided with the cross-shaped connecting structure, and the wave generator comprises various parts, so that the processing and assembling difficulty is increased, and the production cost of the wave generator is improved.

Disclosure of Invention

The invention mainly aims to provide a speed reducer and a robot with the speed reducer, and aims to solve the problem that in the prior art, when the axis of an input end and the axis of the speed reducer have an inclined angle, a wave generator cannot realize a centering function with high coaxiality requirement.

In order to achieve the above object, according to one aspect of the present invention, there is provided a reducer including a flexspline and a wave generator, the wave generator including: a cam; the bearing is sleeved on the cam, the flexible gear is sleeved on the bearing, and the bearing is positioned between the cam and the flexible gear; wherein, the bearing is a joint bearing or a self-aligning roller bearing.

Further, the cam has a shaft hole for inserting an input shaft of the speed reducer; a lubricating oil hole is formed in the cam; the bearing is provided with a bearing inner ring and a bearing outer ring sleeved on the bearing inner ring, the bearing inner ring is sleeved on the cam, and the flexible gear is sleeved on the bearing outer ring; the bearing is provided with a lubricating channel which is communicated with the lubricating oil hole, so that oil entering the lubricating channel from the lubricating oil hole lubricates the space between the bearing inner ring and the bearing outer ring.

Further, the lubricating channel is provided with a first communicating opening and a second communicating opening which are oppositely arranged, the first communicating opening is located on the inner wall of the bearing inner ring of the bearing, and the second communicating opening is located on the outer wall of the bearing outer ring of the bearing.

Furthermore, the joint bearing is provided with a first bearing inner ring and a first bearing outer ring sleeved on the first bearing inner ring, the first bearing inner ring is sleeved on the cam, and the flexible gear is sleeved on the first bearing outer ring; a first through hole is formed in the first bearing inner ring, a second through hole is formed in the first bearing outer ring, and the first through hole is communicated with the second through hole to form a lubricating channel.

Furthermore, the joint bearing also comprises a first sealing ring, and the first sealing ring is arranged at the first end of the joint bearing and is positioned between the first bearing inner ring and the first bearing outer ring; and/or the joint bearing further comprises a second sealing ring, and the second sealing ring is arranged at the second end of the joint bearing and is positioned between the first bearing inner ring and the first bearing outer ring.

Furthermore, the self-aligning roller bearing is provided with a second bearing inner ring and a second bearing outer ring sleeved on the second bearing inner ring, the second bearing inner ring is sleeved on the cam, and the flexible gear is sleeved on the second bearing outer ring; the self-aligning roller bearing also comprises a first roller assembly and a second roller assembly, wherein the first roller assembly and the second roller assembly are both arranged between the inner ring of the second bearing and the outer ring of the second bearing; in the axial direction of the self-aligning roller bearing, a gap is formed between the first roller assembly and the second roller assembly; the second bearing inner ring is provided with a third through hole, the second bearing outer ring is provided with a fourth through hole, and the third through hole is communicated with the fourth through hole through a gap to form a lubricating channel.

Further, the lubricating oil hole and the lubricating passage are provided in pairs; at least two lubricating oil holes are formed in the cam and are arranged around the shaft hole at intervals.

Further, the lubrication oil hole extends in a radial direction of the cam, and the lubrication passage extends in a radial direction of the bearing.

Furthermore, the bearing is provided with a bearing inner ring and a bearing outer ring sleeved on the bearing inner ring, the bearing inner ring is sleeved on the cam, and the flexible gear is sleeved on the bearing outer ring; the thickness from the inner wall of the bearing inner ring to the outer wall of the bearing outer ring along the radial direction of the bearing is d; the aperture of the inner hole of the flexible gear is D; wherein the value range of D/D is 10-15%.

Further, the cam is in interference fit with the bearing, and the bearing is in interference fit with the flexible gear.

According to another aspect of the present invention, there is provided a robot comprising a decelerator, wherein the decelerator is the decelerator described above.

The speed reducer is a harmonic speed reducer and comprises a flexible gear and a wave generator, wherein the wave generator comprises a cam and a bearing, the bearing is sleeved on the cam, the flexible gear is sleeved on the bearing, and the bearing is positioned between the cam and the flexible gear; wherein, the bearing is a joint bearing or a self-aligning roller bearing. The wave generator of the speed reducer is installed in an inner hole of the flexible gear, is connected with the input end and is in a high-speed rotating motion state, the wave generator can automatically adjust the coaxiality of the input end and the speed reducer by adopting the knuckle bearing or the self-aligning roller bearing, and the problem that the wave generator cannot realize the self-aligning function with higher coaxiality requirement when the axis of the input end and the axis of the speed reducer body have inclination angles is solved.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 shows a cross-sectional view of a first embodiment of a retarder according to the invention;

fig. 2 shows a cross-section of a wave generator in a first embodiment of a reducer according to the invention;

fig. 3 shows a cross-section of a wave generator in a second embodiment of a reducer according to the invention.

Wherein the figures include the following reference numerals:

10. a flexible gear; 11. an inner bore; 20. a wave generator; 21. a cam; 211. a shaft hole; 212. a lubricating oil hole; 30. a knuckle bearing; 31. a first bearing inner race; 311. a first through hole; 32. a first bearing outer race; 321. a second through hole; 33. a first seal ring; 34. a second seal ring; 35. a first end; 36. a second end; 40. a self-aligning roller bearing; 41. a second bearing inner race; 411. a third through hole; 42. a second bearing outer race; 421. a fourth via hole; 43. a first roller assembly; 44. a second roller assembly; 45. a gap; 50. a lubrication channel.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The present invention provides a reducer, please refer to fig. 1 to 3, comprising a flexible gear 10 and a wave generator 20, wherein the wave generator 20 comprises: a cam 21; the bearing is sleeved on the cam 21, the flexible gear 10 is sleeved on the bearing, and the bearing is positioned between the cam 21 and the flexible gear 10; wherein, the bearing is a joint bearing 30 or a self-aligning roller bearing 40.

The speed reducer is a harmonic speed reducer, and comprises a flexible gear 10 and a wave generator 20, wherein the wave generator 20 comprises a cam 21 and a bearing, the bearing is sleeved on the cam 21, the flexible gear 10 is sleeved on the bearing, and the bearing is positioned between the cam 21 and the flexible gear 10; wherein, the bearing is a joint bearing 30 or a self-aligning roller bearing 40. The wave generator 20 of the speed reducer is installed in the inner hole 11 of the flexible gear 10, is connected with the input end and is in a high-speed rotating motion state, the wave generator 20 can automatically adjust the coaxiality of the input end and the speed reducer by adopting the knuckle bearing 30 or the self-aligning roller bearing 40, and the problem that the wave generator cannot realize the self-aligning function with higher coaxiality requirement when the axis of the input end and the axis of the speed reducer have an inclined angle is solved.

Specifically, the input end is a driving end of the motor, that is, an output shaft of the motor.

In the present embodiment, the cam 21 has a shaft hole 211, and the shaft hole 211 is used for inserting an input shaft of the speed reducer; a lubricating oil hole 212 is formed in the cam 21; the bearing is provided with a bearing inner ring and a bearing outer ring sleeved on the bearing inner ring, the bearing inner ring is sleeved on the cam 21, and the flexible gear 10 is sleeved on the bearing outer ring; the bearing is provided with a lubricating channel 50, and the lubricating channel 50 is communicated with the lubricating oil hole 212, so that oil entering the lubricating channel 50 from the lubricating oil hole 212 lubricates the space between the bearing inner ring and the bearing outer ring.

Specifically, the speed reducer is installed in a sealing mode, and an oil lubrication mode is adopted. The wave generator is driven by a high-speed input shaft, heat is generated by rotation and stored in a lubricating medium, and the lubricating medium is deteriorated due to overhigh heat, so that the lubricating effect is influenced. The heat dissipation effect of oil lubrication is better than that of grease lubrication, so the oil lubrication effect is better. Further, the sufficient lubrication effect can directly prolong the service life of the bearing.

Specifically, the lubricating oil hole 212 of the cam 21 can lubricate the bearing inner ring; meanwhile, the lubricating oil can lubricate the contact surface between the bearing inner ring and the bearing outer ring. It can be seen that the wave generator 20 can both adjust the coaxiality and achieve lubrication.

In the present embodiment, the lubrication passage 50 has a first communication port and a second communication port that are disposed opposite to each other, the first communication port being located on an inner wall of a bearing inner race of the bearing, and the second communication port being located on an outer wall of a bearing outer race of the bearing.

Specifically, due to the fluidity of the liquid, the lubricating oil enters the cam 21 from the lubricating oil hole 212; under the action of centrifugal force generated by rotation, lubricating oil fully lubricates the space between the outer wall of the bearing inner ring and the inner wall of the bearing outer ring through the lubricating oil hole 212. Lubricating oil flows between the bearing outer ring and the flexible gear 10 after passing through the lubricating channel 50, heat dissipation can be carried out on the flexible gear 10, the circulating lubricating oil is beneficial to heat dissipation of the wave generator during working, and high temperature generated by movement of the bearing is relieved.

In a first embodiment, as shown in fig. 1 and 2, the bearing is a spherical plain bearing 30. The knuckle bearing 30 has a first bearing inner ring 31 and a first bearing outer ring 32 sleeved on the first bearing inner ring 31, the first bearing inner ring 31 is sleeved on the cam 21, and the flexible gear 10 is sleeved on the first bearing outer ring 32; the first bearing inner race 31 is provided with a first through hole 311, the first bearing outer race 32 is provided with a second through hole 321, and the first through hole 311 is communicated with the second through hole 321 to form the lubrication passage 50.

Specifically, the spherical inclination angle of the inner ring and the outer ring of the joint bearing is far larger than that of a common self-aligning rolling bearing, and a rolling friction pair consisting of the first bearing inner ring 31 and the first bearing outer ring 32 can ensure the arc surface contact to achieve the effect of adjusting the installation coaxiality under the action of the cam 21 in the movement process, so that the coaxiality and the verticality of the input end and the speed reducer are ensured.

Specifically, under the adjustment of the spherical inclination angle of the first bearing inner race 31, the first bearing outer race 32 is in interference fit with the flexspline, and the coaxiality of the wave generator 20 and the speed reducer is ensured. Moreover, the first bearing inner ring 31 is a circular arc spherical surface, and the contact mode of the circular arc surface can obtain a stable wave generator profile. In the assembling process, the knuckle bearing facilitates the installation and disassembly of the wave generator, i.e., the wave generator 20 can be screwed into or out of the reducer in a state that the first bearing outer ring 32 is slightly inclined.

In particular, the bearings have play, the magnitude of which affects the outer profile of the wave generator 20 and, consequently, the degree of meshing of the tooth profiles between the flexspline and the rigid spline. In the cooperation of the wave generator 20 with the inner wall of the flexspline 10, a radial play value is mainly active. Generally, the bearing can determine the clearance grade according to national standards, and the working clearance value is stabilized in a certain designed clearance interval in different grade ranges. In the structure of the wave generator 20, the stability of the bearing play value needs to be ensured, the cambered surface contact of the joint bearing increases the contact length, reduces the specific pressure, avoids the condition of the ball gap of the conventional ball bearing, can ensure the stability of the play value, and is beneficial to the meshing transmission of the flexible gear 10 and the rigid gear.

The contact surface between the first bearing inner ring 31 and the first bearing outer ring 32 can ensure the stability of the radial clearance value in the work, specifically, the first bearing inner ring 31 and the first bearing outer ring 32 are in arc surface contact, and the contact mode is in uniform contact in the circumferential direction, so that the radial clearance fluctuation caused by the gap between the rolling balls of the conventional ball bearing is avoided, and the stability of the radial clearance value can be maintained.

In the first embodiment, the oscillating bearing 30 further includes a first seal ring 33, the first seal ring 33 being disposed at a first end 35 of the oscillating bearing 30 between the first bearing inner race 31 and the first bearing outer race 32; and/or, the oscillating bearing 30 further comprises a second seal ring 34, the second seal ring 34 being disposed at a second end 36 of the oscillating bearing 30 between the first bearing inner race 31 and the first bearing outer race 32. The first sealing ring 33 and the second sealing ring 34 can ensure that the lubricating oil can be lubricated between the first bearing inner ring 31 and the first bearing outer ring 32 and flow to the flexible gear 10, and the lubricating oil is prevented from leaking.

In a second embodiment, as shown in fig. 3, the bearing is a self-aligning roller bearing 40. The self-aligning roller bearing 40 is provided with a second bearing inner ring 41 and a second bearing outer ring 42 sleeved on the second bearing inner ring 41, the second bearing inner ring 41 is sleeved on the cam 21, and the flexible gear 10 is sleeved on the second bearing outer ring 42; the self-aligning roller bearing 40 further comprises a first roller assembly 43 and a second roller assembly 44, the first roller assembly 43 and the second roller assembly 44 are both disposed between the second bearing inner race 41 and the second bearing outer race 42; in the axial direction of the self-aligning roller bearing 40, there is a gap 45 between the first roller assembly 43 and the second roller assembly 44; the second bearing inner ring 41 is provided with a third through hole 411, the second bearing outer ring 42 is provided with a fourth through hole 421, and the third through hole 411 is communicated with the fourth through hole 421 through a gap 45 to form a lubricating channel 50.

Specifically, the self-aligning roller bearing 40 itself can adjust the installation coaxiality of the wave generator; under the action of the cam 21, oil lubricates between the first and

second roller assemblies

43 and 44 and the second bearing inner race 41 and the second bearing outer race 42 through the lubrication oil hole 212.

Specifically, the balls in the first roller assembly 43 and the balls in the second roller assembly 44 are both cylinders, and the contact with the second bearing inner ring 41 and the second bearing outer ring 42 is both line contact, and has a larger contact area compared with the rolling ball of a conventional ball bearing and a smaller contact area compared with the cambered surface contact of a joint bearing. The self-aligning roller bearing 40 can also improve the stability of the working play, and the stabilizing effect is between that of a conventional ball bearing and a joint bearing.

In the present embodiment, the lubricating oil hole 212 and the lubricating passage 50 are provided in pairs; the cam 21 is provided with at least two lubrication holes 212, and the at least two lubrication holes 212 are arranged around the shaft hole 211 at intervals. Such setting ensures a lubricating effect and a heat dissipation effect.

In the present embodiment, the lubrication oil hole 212 extends in the radial direction of the cam 21, and the lubrication passage 50 extends in the radial direction of the bearing. Specifically, the pair of the lubricating oil holes 212 and the lubricating passage 50 extend in the same direction.

Specifically, the cam 21 has a short axis and a long axis; the number of the lubricating oil holes 212 is two, the two lubricating oil holes 212 are symmetrically arranged relative to the axis of the cam 21, and the two lubricating oil holes 212 are arranged on the long shaft of the cam, so that the play of the bearing per se can be eaten in the direction of the long shaft when the bearing is used, and the bearing needs to be lubricated more. The long axis here means a portion of the cam 21 having the longest dimension in the radial direction.

In this embodiment, the bearing has a bearing inner ring and a bearing outer ring sleeved on the bearing inner ring, the bearing inner ring is sleeved on the cam 21, and the flexible gear 10 is sleeved on the bearing outer ring; the thickness from the inner wall of the bearing inner ring to the outer wall of the bearing outer ring along the radial direction of the bearing is d; the aperture of an inner hole 11 of the flexible gear 10 is D; wherein the value range of D/D is 10-15%. Specifically, the deformation contour of the bearing is the outer contour of the wave generator, the value range of D/D is set to be 10-15%, the thicknesses of the inner ring and the outer ring of the bearing can be guaranteed to be thin, and the deformation of the bearing is facilitated. The thickness from the inner wall of the bearing inner ring to the outer wall of the bearing outer ring is the thickness from the bearing inner ring directly to the bearing outer ring, and the middle of the bearing inner ring does not pass through the bearing inner ring on the other side with the axis as a boundary.

The thickness d from the inner wall of the bearing inner ring to the outer wall of the bearing outer ring is a single-side thickness between the bearing inner ring and the bearing outer ring.

In this embodiment, there is an interference fit between the cam 21 and the bearing, and an interference fit between the bearing and the flexspline 10.

In the embodiment, in the high-speed rotation with the motor as the input end, the function of adjusting the coaxiality of the wave generator can be realized by adopting the mode that the thin-wall bearing is matched with the cam 21, and in the actual work, the play value is stable, so that the stable outer contour of the wave generator is obtained, and the meshing of a flexible gear and a rigid gear of the speed reducer is facilitated.

The wave generator of the speed reducer of the application is directly connected with the high-speed input end of the motor. The wave generator is arranged in the flexible gear and is integrally used in the sealed working condition of oil lubrication.

The invention realizes the following technical effects: 1. the wave generator has the function of adjusting the coaxiality; 2. the lubricating effect of the wave generator is optimized, and the service life of the wave generator is prolonged; 3. the problem of wave generator bearing play fluctuation is solved, and the stability of bearing working play is enhanced.

The invention also provides a robot, which comprises a speed reducer, wherein the speed reducer is the speed reducer in the embodiment.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:

the speed reducer of the invention is a harmonic speed reducer. The reducer comprises a flexible gear 10 and a wave generator 20, wherein the wave generator 20 comprises a cam 21 and a bearing, the bearing is sleeved on the cam 21, the flexible gear 10 is sleeved on the bearing, and the bearing is positioned between the cam 21 and the flexible gear 10; wherein, the bearing is a joint bearing 30 or a self-aligning roller bearing 40. The wave generator 20 of the speed reducer is installed in the inner hole 11 of the flexible gear 10, is connected with the input end and is in a high-speed rotating motion state, the wave generator 20 can automatically adjust the coaxiality of the input end and the speed reducer by adopting the knuckle bearing 30 or the self-aligning roller bearing 40, and the problem that the wave generator cannot realize the self-aligning function with higher coaxiality requirement when the axis of the input end and the axis of the speed reducer body have an inclined angle is solved.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A reducer comprising a flexspline (10) and a wave generator (20), characterized in that the wave generator (20) comprises:

a cam (21);

the bearing is sleeved on the cam (21), the flexible gear (10) is sleeved on the bearing, and the bearing is positioned between the cam (21) and the flexible gear (10);

wherein the bearing is a joint bearing (30) or a self-aligning roller bearing (40);

the cam (21) is provided with a shaft hole (211), and the shaft hole (211) is used for being inserted into an input shaft of the speed reducer; a lubricating oil hole (212) is formed in the cam (21);

the bearing is provided with a bearing inner ring and a bearing outer ring sleeved on the bearing inner ring, the bearing inner ring is sleeved on the cam (21), and the flexible gear (10) is sleeved on the bearing outer ring;

the bearing is provided with a lubricating channel (50), and the lubricating channel (50) is communicated with the lubricating oil hole (212) so that oil entering the lubricating channel (50) from the lubricating oil hole (212) lubricates the space between the bearing inner ring and the bearing outer ring.

2. A reducer according to claim 1, in which the lubrication channel (50) has a first communication port and a second communication port arranged opposite to each other, the first communication port being located on an inner wall of a bearing inner race of the bearing, and the second communication port being located on an outer wall of a bearing outer race of the bearing.

3. Reducer according to claim 1 or 2, wherein the oscillating bearing (30) has a first inner bearing ring (31) and a first outer bearing ring (32) fitted over the first inner bearing ring (31), the first inner bearing ring (31) being fitted over the cam (21), the flexspline (10) being fitted over the first outer bearing ring (32);

the lubricating device is characterized in that a first through hole (311) is formed in the first bearing inner ring (31), a second through hole (321) is formed in the first bearing outer ring (32), and the first through hole (311) is communicated with the second through hole (321) to form the lubricating channel (50).

4. A reducer according to claim 3, in which the spherical plain bearing (30) further comprises a first sealing ring (33), the first sealing ring (33) being disposed at a first end (35) of the spherical plain bearing (30) between the first bearing inner ring (31) and the first bearing outer ring (32); and/or the presence of a gas in the gas,

the spherical plain bearing (30) further comprises a second seal ring (34), the second seal ring (34) being disposed at a second end (36) of the spherical plain bearing (30) and being located between the first bearing inner ring (31) and the first bearing outer ring (32).

5. Reducer according to claim 1 or 2, wherein the self-aligning roller bearing (40) has a second bearing inner ring (41) and a second bearing outer ring (42) fitted over the second bearing inner ring (41), the second bearing inner ring (41) being fitted over the cam (21), the flexspline (10) being fitted over the second bearing outer ring (42); the self-aligning roller bearing (40) further comprises a first roller assembly (43) and a second roller assembly (44), the first roller assembly (43) and the second roller assembly (44) are both disposed between the second bearing inner ring (41) and the second bearing outer ring (42); a gap (45) is arranged between the first roller assembly (43) and the second roller assembly (44) in the axial direction of the self-aligning roller bearing (40);

and a third through hole (411) is formed in the second bearing inner ring (41), a fourth through hole (421) is formed in the second bearing outer ring (42), and the third through hole (411) is communicated with the fourth through hole (421) through the gap (45) to form the lubricating channel (50).

6. Reducer according to claim 1 or 2, in which the lubrication holes (212) and the lubrication channels (50) are provided in pairs; the cam (21) is provided with at least two lubricating oil holes (212), and the at least two lubricating oil holes (212) are arranged around the shaft hole (211) at intervals.

7. A reducer according to claim 1 or 2, in which the lubrication oil hole (212) extends in the radial direction of the cam (21), the lubrication channel (50) extending in the radial direction of the bearing.

8. A reducer according to claim 1, wherein the bearing has an inner bearing ring and an outer bearing ring fitted over the inner bearing ring, the inner bearing ring being fitted over the cam (21), the flexspline (10) being fitted over the outer bearing ring;

the thickness from the inner wall of the bearing inner ring to the outer wall of the bearing outer ring along the radial direction of the bearing is d; the aperture of an inner hole (11) of the flexible gear (10) is D; wherein the value range of D/D is 10-15%.

9. A reducer according to claim 1, in which there is an interference fit between the cam (21) and the bearing, and between the bearing and the flexspline (10).

10. A robot comprising a decelerator, wherein the decelerator is as claimed in any one of claims 1 to 9.