CN115199724A

CN115199724A - Joint, mechanical arm, robot and harmonic reducer device thereof

Info

Publication number: CN115199724A
Application number: CN202210886233.0A
Authority: CN
Inventors: 王重彬; 胡万权; 叶伟智; 刘主福; 刘培超
Original assignee: Shenzhen Yuejiang Technology Co Ltd
Current assignee: Shenzhen Yuejiang Technology Co Ltd
Priority date: 2021-09-30
Filing date: 2022-07-26
Publication date: 2022-10-18
Also published as: WO2023051714A1; CN113847404A; CN115199725A; CN115289197A

Abstract

The invention relates to the field of robots, and provides a robot, a mechanical arm, a joint and a harmonic reducer device thereof, which comprises a cup-shaped flexible gear, a rigid gear meshed with the flexible gear, a wave generator, an end cover and an output bearing, wherein the wave generator comprises a sleeve for power input, a wave generator main body which is arranged on the sleeve and enables the flexible gear to deform radially under the rotation of the sleeve so as to change the meshing position of the flexible gear and the rigid gear, the wave generator main body also comprises a first stopping structure and a second stopping structure which are arranged oppositely, the first stopping structure and the second stopping structure stop the sleeve, and the projection of the power output end of the wave generator and the second stopping structure on the axis of the sleeve is at least partially overlapped. The invention breaks through the conventional situation that the projection of the power output end of the wave generator and the second stop structure on the axis of the sleeve is at least partially overlapped, and under the condition that the radial size of the rigid wheel is not changed, the axial size of the harmonic reducer device is directly changed, so that the requirement of more miniaturization of the harmonic reducer device is met, and the market requirement is met.

Description

Joint, mechanical arm, robot and harmonic reducer device thereof

The present application claims priority from chinese patent application No. 202111164470.8 entitled "joint, robot arm, robot and harmonic reducer device thereof" filed by chinese patent office at 30/09/2021, the entire contents of which are incorporated herein by reference.

Technical Field

The invention relates to the technical field of robots, in particular to a joint, a mechanical arm, a robot and a harmonic reducer device thereof.

Background

The robot generally comprises a mechanical arm and a joint for rotating the mechanical arm, wherein a harmonic reducer is used for speed regulation at the joint. The harmonic reducer consists of three main components, which are respectively a fixed rigid gear, a flexible gear and a wave generator for radially deforming the flexible gear. The inner wheel is provided with an inner gear, the flexible gear is an easily-deformed thin-wall cylindrical outer gear, power is transmitted through the meshing of the inner gear and the outer gear, under the action of a wave generator, gaps between the teeth of the rigid gear and the flexible gear are uniform, at the moment, no speed reduction power is transmitted, under the action of the wave generator, a generator arranged in the flexible gear enables the flexible gear to be radially deformed into an ellipse, at the moment, the teeth are meshed along the whole working height on the long axis of the ellipse, radial gaps are formed between tooth tops on the short axis, and the shape of the flexible gear is always close to the ellipse in the rotating process of the generator, so that speed reduction transmission is realized.

The harmonic reducer has the advantages of high bearing capacity, large transmission ratio, small volume, stable transmission and high transmission precision, and is widely applied to the industries of electronics, aerospace, robots and the like.

Referring to fig. 1, a flexible gear 10 includes a cylinder 11 and an annular fixed table 12 that is perpendicular to an axis of the cylinder 11 and is folded outward, a central cavity (not shown) that extends along the axis direction and completely penetrates through a core of the cylinder 11 is formed in a core of the cylinder 11, and an annular gear belt 13 that extends along the axis direction and is distributed by a single gear in an annular array is disposed on an outer circumferential surface of the cylinder 11. When the size of the cylinder 11 of the flexspline is determined, the size of the harmonic reducer 100 cannot be further reduced in the space region occupied by the annular mount 12 due to the presence of the outwardly folded annular mount 12.

In the technological research and development process for many years, researchers invented a cup-shaped flexible gear and apply it to a harmonic reducer, please refer to fig. 2, the flexible gear 10a includes an annular rotator 11a and an annular fixed table 12a which is perpendicular to the axis of the annular rotator 11a and is turned inwards, since the silk hat-shaped flexible gear 10 is replaced by the cup-shaped flexible gear 10a, the space area occupied by the outward turned fixed table 12 of the silk hat-shaped flexible gear 10 is reduced, the harmonic reducer 100a has a smaller size, the size of the robot joint using the harmonic reducer 100a is also smaller, and the whole robot is very small.

However, with the enthusiasm of people on robots, the demand for miniaturization of robots is higher, the miniaturization is mainly embodied in joint parts, smaller harmonic reducers are hot spots in the market, and over the past years, no more miniaturized products are available in the market.

Disclosure of Invention

The embodiment of the invention aims to provide a harmonic reducer device to solve the technical problem that the size of the conventional harmonic reducer device cannot meet the requirement of people on miniaturization.

In order to realize the purpose, the invention adopts the technical scheme that: the utility model provides a harmonic speed reducer device, including cupped flexbile gear, with flexbile gear engaged with rigid gear and wave generator, wave generator including supply power input's sleeve and set up in on the sleeve and make under telescopic rotation the flexbile gear takes place radial deformation in order to change the flexbile gear with the wave generator main part of rigid gear meshing position, harmonic speed reducer device is still including the relative end cover and the output bearing that set up, harmonic speed reducer device still includes right the sleeve carries out first backstop structure and the second backstop structure of backstop, the power take off end of wave generator with second backstop structure is in projection on the telescopic axis is partial overlapping at least.

In one embodiment, the projection overlap ratio of the power output end of the wave generator and the second stop structure on the axis of the sleeve is in the range of 0.1-1.

In one embodiment, the projection overlap ratio of the power output end of the wave generator and the second stop structure on the axis of the sleeve is in the range of 0.5-0.9.

In one embodiment, the second stop structure is a stop bearing.

In one embodiment, the harmonic reducer apparatus further includes an output shaft fixedly connected to the inner race of the output bearing, and the second stop structure is located between the output shaft and the sleeve.

In one embodiment, the first stopping structure is a non-bearing structure and is sleeved on the sleeve.

In one embodiment, a gap is formed between the sleeve and the end cap, and the first stop structure seals the gap.

In one embodiment, the axial dimension of the first stop structure is less than the difference between the inner and outer diameters of the first stop structure.

In one embodiment, the first and second stop structures provide axial bi-directional stops for the sleeve.

In one embodiment, the outer annular surface of the sleeve is formed with a first step, the outer side surface of the end cap is formed with a surrounding plate, and the first stopping structure is arranged between the first step and the surrounding plate.

In one embodiment, the first stopping structure includes a stopping member sleeved on the sleeve and rotating along with the rotation of the sleeve, and a sealing member rotating relative to the stopping member, the sealing member is fixedly connected with the end cover, the stopping member abuts against the first step, and the sealing member abuts against the enclosing plate.

In one embodiment, a sealing structure is formed between the stopper and the sealing element, the sealing structure comprises an annular groove and a convex ring inserted into the annular groove, one of the stopper and the sealing element is provided with the annular groove, and the other of the stopper and the sealing element is provided with the convex ring in a protruding mode.

In one embodiment, at least one of the stopper and the seal is sheet-like.

In one embodiment, the first stopping structure comprises a stopping part sleeved on the sleeve and rotating along with the rotation of the sleeve and a sealing part connected to the stopping part; the inner side face of one end of the stop piece abuts against the first step, and the outer side face of one end of the sealing piece abuts against the coaming.

In one embodiment, the seal member and the closure are in constant contact as the seal member rotates, and a seal is formed at the contact between the seal member and the closure.

In one embodiment, the stop member includes a fixing portion having a U-shaped cross section, an extending portion extending in a direction away from the sleeve from one side of the fixing portion close to the wave generator main body, and an inclined portion extending in a direction away from the sleeve and inclined toward the shroud from a side edge of the extending portion away from the sleeve, and the sealing member includes a stopper portion fixed in the fixing portion and a contact portion extending in an inclined direction toward the shroud from one side of the stopper portion away from the sleeve and close to the shroud, the contact portion being in contact with the shroud.

In one embodiment, the outer side surface of the end cap is formed with a surrounding plate, the first stopping structure comprises a connecting ring connected to one side of the surrounding plate close to the sleeve, and a sealing structure is formed between the connecting ring and the outer annular surface of the sleeve.

In one embodiment, the connection ring is in surface contact with the outer annular surface of the sleeve, and the sealing structure is at least one annular groove formed in the contact surface between the connection ring and the sleeve.

In one embodiment, the end cap includes a body, the rigid wheel is fixed between an inner end face of the body and an outer ring of the output bearing, and the shroud is connected to an outer end edge of the body and is integral with the body.

In one embodiment, the outer ring surface of the output shaft is convexly provided with a mounting part, and the mounting part and the cup bottom part of the flexible gear are fixed on the inner ring of the output bearing together.

In one embodiment, the inner annular surface of the sleeve is provided with a second step; one side of the stop bearing abuts against the second step, the other side of the stop bearing indirectly abuts against the cup bottom of the flexible gear, and the outer ring of the stop bearing abuts against the second step.

In one embodiment, the harmonic reducer device further comprises an output shaft fixedly connected with the inner ring of the output bearing, and another end cover located outside the output bearing, the another end cover being connected to the inner ring of the output bearing.

In one embodiment, the other end cover and the output shaft are two independent parts, and a wire harness structure is arranged between the other end cover and the output shaft.

In one embodiment, the output bearing is a self-contained bearing.

In one embodiment, the wave generator body includes a rotation arm formed on the sleeve and rollers mounted at opposite ends of the rotation arm; or, the wave generator body comprises a cam formed on the sleeve and a flexible bearing connected to the cam; alternatively, the wave generator body comprises an elliptical disc formed on the sleeve and a compliant bearing connected to the elliptical disc.

An object of an embodiment of the present invention is to further provide a joint, which includes the harmonic reducer device in the above embodiment and a driving motor for inputting power to the sleeve.

In one embodiment, the joint further comprises another bearing sleeved on the sleeve and a mounting part for limiting the another bearing, an accommodating space is formed between a stator and a rotor of the motor, and the another bearing is located in the accommodating space.

In one embodiment, the mounting member includes a plate body and a limiting ring connected to one side of the plate body, the limiting ring and the sleeve radially limit the other bearing, a third step is formed on an outer circumferential surface of the sleeve, and the third step and the plate body axially limit the other bearing.

An object of an embodiment of the present invention is to further provide a robot arm, which includes the joint in the above embodiment.

The embodiment of the invention aims to further provide a robot, which comprises the mechanical arm in the embodiment.

The invention has the following beneficial effects:

the harmonic reducer device in the embodiment breaks through the conventional structure, and creatively improves the structural position relation between the second stopping structure and the power output end of the wave generator, so that the projection of the power output end of the wave generator and the second stopping structure on the axial line of the sleeve is at least partially overlapped, the axial size of the harmonic reducer device is reduced, and the harmonic reducer device contributes to the miniaturization development of the harmonic reducer device. Under the condition that the radial size of the rigid wheel is not changed, the axial size of the harmonic reducer device is directly changed, the requirement for miniaturization of the harmonic reducer device is met, and the market requirement is met.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required to be used in the embodiments or the prior art description will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings may be obtained according to these drawings without inventive labor.

Fig. 1 is a schematic cross-sectional view of a harmonic reducer using a silk hat type flexspline.

Fig. 2 is a schematic sectional view of a harmonic reducer using a cup-type flexspline.

Fig. 3 is a schematic perspective view of a robot according to an embodiment of the present invention.

Fig. 4 is a schematic plan view of the robot shown in fig. 3.

Fig. 5 is an assembly view of one of the joints of the robot shown in fig. 4.

FIG. 6 isbase:Sub>A cross-sectional view of the joint of FIG. 5 taken along line A-A, wherein the first embodiment harmonic reducer assembly is applied to the joint.

Fig. 7 shows a comparison of the harmonic reducer assembly provided by the first embodiment of the present invention with the harmonic reducer of fig. 2 in axial dimension.

Figure 8 is an enlarged view of a portion of the joint of figure 5.

Fig. 9 is an enlarged view of fig. 8 at circle B.

FIG. 10 isbase:Sub>A cross-sectional view of the joint of FIG. 5 taken along line A-A, whereinbase:Sub>A harmonic reducer assembly of the second embodiment is applied to the joint.

Figure 11 is an enlarged view of the joint of figure 10 taken at circle C.

FIG. 12 isbase:Sub>A cross-sectional view of the joint of FIG. 5 taken along line A-A, wherein the third embodiment harmonic reducer assembly is applied to the joint.

Figure 13 is an enlarged view of the joint of figure 12 taken at circle D.

Fig. 14 shows a comparison of the harmonic reducer apparatus provided by the third embodiment of the present invention with the harmonic reducer of fig. 2 in axial dimension.

FIG. 15 isbase:Sub>A cross-sectional view of the joint of FIG. 5 taken along line A-A, wherein the fourth embodiment harmonic reducer assembly is applied to the joint.

FIG. 16 isbase:Sub>A cross-sectional view of the joint of FIG. 5 taken along line A-A, whereinbase:Sub>A fifth embodiment harmonic reducer assembly is applied to the joint.

FIG. 17 isbase:Sub>A cross-sectional view of the joint of FIG. 5 taken along line A-A, wherein the joint hasbase:Sub>A sixth embodiment ofbase:Sub>A harmonic reducer assembly applied thereto.

FIG. 18 isbase:Sub>A cross-sectional view of the joint of FIG. 5 taken along line A-A, wherein the harmonic reducer assembly of the seventh embodiment is applied to the joint.

FIG. 19 isbase:Sub>A cross-sectional view of the joint of FIG. 5 taken along line A-A, wherein the eighth embodiment harmonic reducer assembly is applied to the joint.

FIG. 20 isbase:Sub>A cross-sectional view of the joint of FIG. 5 taken along line A-A, whereinbase:Sub>A ninth embodiment harmonic reducer assembly is applied to the joint.

Fig. 21 shows a comparison of the harmonic reducer apparatus provided by the first embodiment of the present invention and the harmonic reducer apparatus shown in fig. 18 in the axial dimension.

FIG. 22 isbase:Sub>A cross-sectional view of the joint of FIG. 5 taken along line A-A, wherein the tenth embodiment harmonic reducer assembly is applied to the joint.

Fig. 23 is a perspective view showing a joint of a robot according to an embodiment of the present invention, to which a harmonic reducer device according to a seventh embodiment is applied.

Figure 24 is a cross-sectional schematic view of the joint shown in figure 23.

Fig. 25 is a schematic partial sectional view of a robot according to an embodiment of the present application, in which a joint used in the robot joint is a harmonic reducer device according to a seventh embodiment.

The reference numbers are specified as follows:

10. a flexible gear; 11. a cylinder; 12. a fixed table; 13. a cogged belt; 100. a harmonic reducer;

10a, a flexible gear; 11a, a rotator; 12a, a fixed table; 100a, harmonic reducers; 20a, a wave generator; 21a, a sleeve; 22a, a roller; 30a, a first positioning bearing; 40a, a second positioning bearing; 50a, a first end cover; 60a, a rigid wheel; 70a, roller bearings; 51a, a connecting flange; 71a, an outer ring of the roller bearing 70 a; 80a, an output shaft; 52a, a fixing plate; 81a, a gasket; 82a, a radial connection; 83a, an axial ring portion; 93a, a second end cap; 95a and the inner side of the second end cover 93a are provided with oil seals;

200. a robot; 2001. an outer housing; 2002. turning; 203. a base; 201. a mechanical arm; 202. an arm body; 204. a joint; 9. a motor; 100b, a harmonic reducer device; 10b, a flexible gear; 60b, a rigid wheel; 20b, a wave generator; 21b, a sleeve; 22b, a wave generator body; 90b, end caps; 70b, an output bearing; 30b, a first stop structure; 40b, a second stop structure; 40b, a stopper bearing; 91b, a coaming; 92b, end cap 90 b; 61b, a first fixing member; 80b, an output shaft; 81b, a washer; 82b, a mounting part; 93b, the other end cover; 1b, a wire harness structure; 95b and the output bearing 70b are provided with oil seals; 209. a housing of the brake 205; 208. a limiting ring; 207. a plate body; 206. a mounting member; 205. a brake; 92. a stator; 91. a rotor; 101. another bearing; 11b, a ring portion; 12b, a cup bottom; 14b, an accommodating space; 23b, a first step; 24b, a second step; 72b, inner race of output bearing 70 b; 31b, a stopper; 32b, a seal; 33b, a sealing structure; 34b, a ring groove; 35b, a convex ring; 36b, groove wall surfaces; 37b, the groove bottom surface; 38b, corners; 94b, a connecting part; 101b, a pipe body; 102b, an expansion part; 103b, a cable; 2b, the outer periphery of the mount 206; 94. a housing of the motor 9; 93. an accommodating space; 95. an elastic member; 27b, a third step; 25b, an elliptical disk; 26b, a flexible bearing; 73b, a containing groove;

100c, a harmonic reducer device; 21c, a sleeve; 30c, a first stop structure; 31c, a stopper; 32c, a seal; 23c, a first step; 91c, a coaming; 22c, a wave generator body; 301c, a fixing portion; 302c, an extension; 303c, an inclined portion; 320c, a stop portion; 321c, a contact portion;

100d, a harmonic reducer device; 21d, a sleeve; 30d, a first stop structure; 90d, end covers; 91d, enclosing plates; 92d, a connecting ring; 33d, a sealing structure; 34d, a ring groove; 36d, groove wall surfaces; 37d, the bottom surface of the groove; 38d, corners; 9d, a motor; 921d, stator; 911d, rotor; 93d, an accommodating space;

100e, a harmonic reducer device; 93e, the other end cover; 80e, an output shaft; 70e, an output bearing; 72e, an inner ring of the output bearing 70 e; 10e, a flexible gear; 12e, the bottom of the cup;

100f, a harmonic reducer device; 93f, the other end cover; 80f, an output shaft; 70f, an output bearing; 72f, inner race of output bearing 70 f; 10f, a flexible gear; 12f, the bottom of the cup;

100g, harmonic reducer device; 93g, the other end cover; 80g, an output shaft; 70g, an output bearing; 72g, inner ring of output bearing 70 g; 10g, a flexible gear; 12g, the bottom of the cup;

100h, a harmonic reducer device; 30h, a first stop structure; 91h, enclosing plates; 23h, a first step; 95h, an elastic piece; 9h, a motor; 92h, a stator; 94h, a rotor; 93h, an accommodating space; 96h, convex hull; 97h, a cavity; 204h, joints; 21h, a sleeve; 2041. a motor end encoder; 205h, a brake; 209h, brake 205 h; 40h, a second stop structure; 2042. a servo driver power board; 209h, a brake fixing seat; 80h, an output shaft; 2043. a load side encoder; 2044. a servo driver control board; 2045. a cable fixing plate; 9h, a motor;

100i, a harmonic reducer device; 93i, the other end cover; 80i and an output shaft; 70i, an output bearing; 72i, inner race of output bearing 70 i; 10i, a flexible gear; 12i, a cup bottom;

100k, harmonic reducer unit; 30k, a first stop structure; 91b, a coaming; 90k, an end cover; 910k, a projecting ring portion; 9k, a motor; 92k, a stator; 91k, rotor; 98k, an accommodating space; 920k, a check ring; 23k, a first step; 21k, a sleeve; 80k, an output shaft; 40k, a second stop structure; 40k, a seal; 34k, a ring groove; 24k, a second step; 10k, a flexible gear; 12k, the bottom of the cup; 101k, another bearing; 22k, a wave generator body.

100n, harmonic reducer devices; 205n, a brake; 9n, a motor; 101n, another bearing; 206n, a mount; 207n, plate body; 208n, a limit ring; 21n, a sleeve; 211n, a fixing sleeve; 212n, a third step; 94n, a motor shell; 209n, a brake fixing seat; 93n and an accommodating space.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

In the description of the present invention, it is to be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate orientations or positional relationships based on those shown in the drawings, and are merely for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.

In addition, in the present invention, in each embodiment in claims, if "second" appears first in the embodiment, it does not mean that "first" is necessarily present in the embodiment. "first" and "second" are used for descriptive purposes only, and elements called the same name are distinguished by "first" and "second", e.g., a first step, a second step, where "first" and "second" merely distinguish this structure of steps.

In the present invention, unless otherwise expressly stated or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

With the enthusiasm of people on robots, the requirement on the miniaturization of the robots is higher, the miniaturization is mainly embodied in joint parts, smaller harmonic reducers are hot spots in the market, and over the past years, no more miniaturized product is available in the market. Referring to fig. 2 again, the cup-shaped flexspline 10a is applied to a harmonic reducer to achieve the purpose of reducing the size of the harmonic reducer, and simultaneously, the sleeve 21a of the wave generator 20a is provided with a first positioning bearing 30a and a second positioning bearing 40a respectively corresponding to the inner end and the outer end of the roller 22a to achieve the axial bidirectional positioning of the sleeve 21a, and the structural schemes of the cup-shaped flexspline 10a, the sleeve 21a, the first positioning bearing 30a and the second positioning bearing 40a shown in fig. 2 are currently preferred alternatives, and in the process of developing toward a smaller harmonic reducer, researchers have generated a fixed thinking and do not change the structural schemes of the cup-shaped flexspline 10a, the sleeve 21a, the first positioning bearing 30a and the second positioning bearing 40a shown in fig. 2, but make efforts toward other directions, for example:

1. the first end cap 50a is modified so that no innovation can be made in the size of the first end cap 50 a;

2. the rigid wheel 60a is improved, and innovation cannot be made on the size of the rigid wheel 60 a;

3. the flexible gear 10a is improved, and innovation cannot be made on the size of the flexible gear 10 a;

4. the roller bearing 70a is improved, innovation cannot be made from the size of the roller bearing 70a, and so on.

However, many years of effort by researchers in the industry have not resulted in good results. Specifically, regarding point 1, the first end cover 50a has to satisfy the fixed connection strength of the connection flange 51a, the rigid wheel 60a and the outer ring 71a of the roller bearing 70a, and also leave a receiving space for the first positioning bearing 30a, which is difficult to break through; for the point 2 and the point 3, the harmonic reducer 100a adjusts the rotation speed through the change of the meshing position of the rigid gear 60a and the flexible gear 10a, after a certain rotation speed ratio is determined, the parameters of the meshing teeth of the flexible gear 10a and the rigid gear 60a are fixed, and are limited by the existing gear processing level, and it is difficult to achieve the same rotation speed ratio through smaller meshing teeth, so the purpose of reducing the volume through adjusting the radial size of the flexible gear 10a and the rigid gear 60a is difficult to achieve, in addition, the power transmission is achieved through the meshing of the flexible gear 10a and the rigid gear 60a, the structural strength of the flexible gear 10a and the rigid gear 60a reaches the standard, and the breakthrough from the axial size of the flexible gear 10a and the rigid gear 60a is difficult; as for the point 4, the roller bearing 70a is a direct component for transmitting power to the output shaft 80a, and the structural strength thereof also needs to be satisfied, and there is no substantial breakthrough in the size of the roller bearing 70 a.

So for many years no more miniaturized product has appeared on the market. However, the applicant also carries out the research of this technology with a huge research and development cost, breaking through the original structural scheme (as shown in fig. 2) of the cup-shaped flexible gear 10a, the sleeve 21a, the first positioning bearing 30a and the second positioning bearing 40a, and innovatively providing a brand-new structural scheme, so that the harmonic reducer 100a is more miniaturized on the basis of the originally smaller scheme. In the case of further miniaturization of the harmonic reducer 100a, the joint to which the harmonic reducer 100a is applied is also further miniaturized, and at the same time, the robot to which the joint is applied is also further miniaturized.

The following describes specific implementations of the present invention in more detail with reference to specific embodiments:

referring to fig. 3 and 4, an embodiment of the invention provides a robot 200, which includes a base 203 and a robot arm 201 connected to the base 203, wherein the robot arm 201 includes at least two arm bodies 202 and a joint 204 connected between the arm bodies 202, and the movement of the robot arm 201 is realized through the joint 204.

Referring to fig. 5 and fig. 6, the joint 204 includes the motor 9 and the harmonic reducer device 100b connected to the motor 9. Fig. 5 and 6 show a harmonic reducer apparatus 100b provided in a first embodiment of the present invention.

The harmonic reducer apparatus 100b includes a cup-shaped flexible gear 10b, a rigid gear 60b engaged with the flexible gear 10b, and a wave generator 20b. The wave generator 20b includes a sleeve 21b to which power is input, and a wave generator body 22b that is provided on the sleeve 21b and radially deforms the flexspline 10b under rotation of the sleeve 21b to change a meshing position of the flexspline 10b with the rigid spline 60b.

The harmonic reducer assembly 100b also includes an end cap 90b and an output bearing 70b disposed in opposition. The harmonic reducer device 100b further includes a first stop structure 30b and a second stop structure 40b that stop the sleeve 21b. The first stopping structure 30b is a non-bearing structure and is sleeved on the sleeve 21b.

The axial dimension of the first stop structure 30b is smaller than that of a conventional bearing providing an axial stop function, e.g., the axial dimension of the first stop structure 30b is smaller than that of the first positioning bearing 30a shown in fig. 2.

The harmonic reducer device 100b in the present embodiment breaks through the conventional structure, and the first stopper structure 30b does not employ a bearing structure, but replaces the conventional bearing with the first stopper structure 30b having a smaller axial dimension than that of the conventional bearing that provides the axial limit function, thereby achieving an innovative break in the reduction of the axial dimension. Because the existing bearing needs to add balls between the inner ring and the outer ring, in order to ensure that the balls can safely and reliably run between the inner ring and the outer ring, the axial sizes of the inner ring and the outer ring cannot be made to be small, the bearing is directly broken through the use of abandoning the bearing conventionally, and the axial size is changed into the first stop structure 30b smaller than that of the conventional bearing, under the condition that the radial size of the rigid wheel 60b is not changed, the requirement of more miniaturization of the harmonic reducer device 100b is met directly by changing the axial size of the harmonic reducer device 100b, and the market requirement is met. It should be noted that the conventional bearing may be the first positioning bearing 30a shown in fig. 2.

Referring to fig. 7, fig. 7 is a comparison diagram of the harmonic reducer device 100b according to the embodiment of the present invention and the harmonic reducer 100a of fig. 2 in the axial dimension, and it can be seen from the diagram that the axial dimension is significantly reduced under the same radial dimension L of the rigid wheel 60b, specifically, the distance between the two can be measured by taking the element having the function of limiting the left side of the first stopping structure 30b as a starting point (the fixing plate 52a is taken as a starting point for fig. 2, and the left side of the surrounding plate 91b itself is taken as a starting point for fig. 7) and the cup bottom 12b of the flexible wheel 10b as an ending point, where A1 is significantly smaller than A2, and the harmonic reducer device 100b according to the embodiment of the present invention is significantly reduced in the axial dimension than the harmonic reducer 100a of fig. 2. In this embodiment, a reduction of 5mm to 13mm is specified. Preferably, the reduction is 8mm to 10mm.

Referring again to fig. 5 and 6, a gap (not shown) is formed between the sleeve 21b and the end cap 90 b. The first stop structure 30b seals the gap.

In the present embodiment, the first and

second stop structures

30b and 40b provide axial bi-directional stops for the sleeve 21b.

The outer circumferential surface of the sleeve 21b is formed with a first step 23b. The outer side surface of the end cover 90b is formed with a shroud 91b. The first stop 30b is disposed between the first step 23b and the fence 91b. The first stopper structure 30b is restricted in its bidirectional movement in the axial direction of the sleeve 21b by the first step 23b and the collar 91b. In the present embodiment, the first step 23b is formed by reducing the diameter of the sleeve 21b at a position corresponding to the first stopper structure 30b of the sleeve 21b. In other embodiments, the first step 23b may be formed by increasing the diameter of the sleeve 21b on the right side of the sleeve 21b at a position corresponding to the first stopper structure 30b, where the "right side" refers to a side of the first stopper structure 30b close to the wave generator body 22b.

In this embodiment, the first stopping structure 30b includes a stopping member 31b sleeved on the sleeve 21b and rotating along with the rotation of the sleeve 21b and a sealing member 32b rotating relative to the stopping member 31b, the sealing member 32b is fixedly connected with the end cover 90b, the stopping member 31b abuts against the first step 23b, and the sealing member 32b abuts against the enclosing plate 91b. By replacing the bearing structure by two relatively rotating stops 31b and seals 32b, a smaller axial dimension can be achieved without impeding the rotation of the sleeve 21b relative to the end cap 90 b.

The revolute pair between the stopper 31b and the seal 32b is formed at a portion overlapping between the outside of the stopper 31b and the inside of the seal 32b. Here, the outer side of the stopper 31b refers to a side away from the wave generator main body 22b, and the inner side of the seal 32b refers to a side close to the wave generator main body 22b.

The projections of the seal 32b and the stopper 31b in the direction parallel to the axis of the sleeve 21b at least partially overlap. The first stop structure 30b is formed as a revolute pair at the overlapping portion.

The position of the stopper 31b and the sleeve 21b is fixed relatively, so that the stopper 31b rotates with the rotation of the sleeve 21b. Seal 32b is fixedly attached to end cap 90b such that stop 31b acts as a rotor and seal 32b acts as a stator.

In the present embodiment, the first stopping structure 30b is composed of the stopping member 31b and the sealing member 32b, the first stopping structure 30b is composed of only two parts, and is one part less in number than the conventional bearing, specifically, the conventional bearing is composed of three parts including an inner ring, an outer ring and balls disposed between the inner ring and the outer ring, whereas the first stopping structure 30b in the present invention is composed of only two parts, i.e., the stopping member 31b and the sealing member 32b. The invention has great breakthrough in reducing material cost caused by reducing parts.

In this embodiment, the axial dimension of the first stop structure 30b is less than the difference between the inner and outer diameters of the first stop structure 30 b. The harmonic reducer device 100b in the present embodiment breaks through the conventional structure, and the first stopper structure 30b does not adopt a bearing structure, but adopts the first stopper structure 30b having an axial dimension smaller than the difference between the inner diameter and the outer diameter instead of the conventional bearing, thereby achieving an innovative breakthrough in the reduction of the axial dimension. Because the existing bearing needs to add balls between the inner ring and the outer ring, in order to ensure the balls to safely and reliably run between the inner ring and the outer ring, the axial sizes of the inner ring and the outer ring cannot be made small, and usually, the axial size of the inner ring or the outer ring is equal to the difference between the inner diameter and the outer diameter of the bearing or the axial size of the inner ring or the outer ring is larger than the difference between the inner diameter and the outer diameter of the bearing, wherein the difference between the inner diameter and the outer diameter of the bearing refers to the difference between the diameters of the inner ring and the outer ring or the difference between the diameters of the inner ring and the outer ring. The invention directly breaks through the conventional situation that the use of the bearing is abandoned, and the structure that the axial size is smaller than the difference between the inner diameter and the outer diameter is changed, under the condition that the radial size of the rigid wheel 60b is not changed, the axial size of the harmonic reducer device 100b is directly changed, the requirement of more miniaturization of the harmonic reducer device 100b is met, and the market requirement is met.

In the present embodiment, a seal structure 33b is formed between the stopper 31b and the seal 32b to achieve a sealing function and prevent leakage of the lubricating oil in the cavity of the harmonic reducer device 100b.

In the present embodiment, the sealing structure 33b includes an annular groove 34b and a convex ring 35b inserted into the annular groove 34b, one of the stopper 31b and the sealing element 32b is provided with the annular groove 34b, and the other of the stopper 31b and the sealing element 32b is provided with the convex ring 35b in a protruding manner. By the engagement of the annular groove 34b with the protruding ring 35b, not only the relative rotation between the stopper 31b and the seal 32b is not hindered, but also a sealing function is provided for the rotation pair between the stopper 31b and the seal 32b. The specific sealing effect is realized by the labyrinth matching surface of the annular groove 34b and the convex ring 35b.

Referring to fig. 8 and 9, in the present embodiment, at least three mating surfaces of the annular groove 34b and the protruding ring 35b include two groove wall surfaces 36b and a groove bottom surface 37b connecting the two groove wall surfaces 36 b. A corner 38b is formed between the groove bottom surface 37b and each groove wall surface 36 b. The arrangement is such that even if the lubricant oil is going to flow out, the lubricant oil must pass through the two groove wall surfaces 36b, the one groove bottom surface 37b and the two corners 38b, and the long path finally prevents the lubricant oil from flowing out, so as to achieve the purposes of sealing and leakage prevention.

The axial dimension between the stopper 31b and the seal 32b is further reduced by the fitting arrangement of the annular groove 34b and the projecting ring 35b. Meanwhile, the stopper 31b has a certain supporting function for the sealing member 32b by the engagement of the annular groove 34b and the protruding ring 35b, and of course, the stopper 31b also has a certain supporting function for the end cap 90b by the sealing member 32b.

The annular groove 34b and the protruding ring 35b are provided in pairs, and may be provided in one pair, two pairs, three or more pairs, or the like. The specific set number of pairs is required to be determined by the radial dimension difference between the end cover 90b and the sleeve 21b and the thickness of the convex ring 35b, where the radial dimension difference between the end cover 90b and the sleeve 21b refers to the radial distance between the end cover 90b and the sleeve 21b, specifically, the radial distance between the main body 92b of the end cover 90b and the sleeve 21b. In the present embodiment, the ring grooves 34b and the collars 35b are provided in two pairs.

At least one of the stopper 31b and the sealing member 32b is in the form of a sheet. The sheet-like shape here means that the axial dimension is smaller than the difference between the inner and outer diameters. In the present embodiment, the stopper 31b and the seal 32b are both in the form of a sheet, the axial dimension of the stopper 31b is smaller than the difference between the inner and outer diameters of the stopper 31b, and the axial dimension of the seal 32b is smaller than the difference between the inner and outer diameters of the seal 32b. In other embodiments, one of the stopper 31b and the sealing member 32b may be provided in a sheet structure.

End cap 90b includes a body 92b that holds rigid wheel 60b between the inner end face of body 92b and the outer race of output bearing 70b. The inner end surface of the main body 92b as referred to herein means the end surface of the main body 92b near the output bearing 70b. An annular cavity is formed between the inner end face of the main body 92b and the outer race of the output bearing 70b, and the rigid gear 60b is disposed in the annular cavity and sandwiched between the inner end face of the main body 92b and the outer race of the output bearing 70b. The main body 92b, the rigid gear 60b, and the outer race of the output bearing 70b are fixed together by the first fixing member 61 b.

In the present embodiment, the shroud 91b is connected to the outer end edge of the main body 92b and is integral with the main body 92 b. That is, the shroud 91b does not exist as a separate component, but is integrated with the main body 92b of the end cap 90b, so that the number of components can be reduced, the additional processing cost of the shroud 91b as a separate component is reduced, the processing and assembling processes of the shroud 91b as a separate component are also reduced, and the cost of the harmonic reducer apparatus 100b is saved to some extent. Referring to fig. 2 again, the component serving as the enclosing plate 91b is the fixing plate 52a on the outer side of the first end cap 50a, and the fixing plate 52a exists as a separate component in fig. 2, which substantially increases the number of components, also increases the inventory space, increases the inventory control types of the components, and also increases the manufacturing process and the assembling process, and of course, increases the cost.

In the present embodiment, the flexible gear 10b has a cup shape, and includes a ring portion 11b and a cup bottom portion 12b connected to the ring portion 11 b. The cup bottom portion 12b is formed by extending inward from one end edge of the ring portion 11 b. The cup bottom 12b is formed with a through hole (not shown) for the output shaft 80b to pass through. The outer circumferential surface of the ring portion 11b is provided with an external gear (not shown) for meshing with an internal gear (not shown) of the ring gear 60b. The ring portion 11b and the cup bottom portion 12b form an accommodating space 14b, and the wave generator body 22b and the second stopper 40b are located in the accommodating space 14 b.

The ring gear 60b has a ring shape, and an internal gear is formed inside thereof and engaged with the flexible gear 10 b. The flexspline 10b is disposed in the interior cavity of the rigid spline 60b.

In this embodiment, the second stop structure 40b is a stop bearing 40b, and the power take-off of the wave generator 20b at least partially overlaps the projection of the stop bearing 40b on the axis of the sleeve 21b. So arranged, the overall axial dimensions of the stop bearing 40b and of the power take-off of the wave generator 20b are reduced, and with reference again to fig. 2, the power take-off of the wave generator 20a in the harmonic reducer 100a shown in fig. 2 does not overlap at all with the projection of the second positioning bearing 40a on the axis of the sleeve 21 a. In the present invention, there is an overlap between the power output end of the wave generator 20b and the projection of the stopper bearing 40b on the axis of the sleeve 21b, and the size in the axial direction of the sleeve 21b is smaller. The consistent design scheme in the harmonic reducer device in the industry is as shown in fig. 2, two

stop bearings

30a and 40a are arranged on two opposite sides of the power output end of the wave generator 20a, and are not overlapped, but the invention breaks through the conventional scheme, creatively improves the structural position relationship between the stop bearing 40b and the power output end of the wave generator 20b, enables the projection of the power output end of the wave generator 20b and the stop bearing 40b on the axis of the sleeve 21b to be at least partially overlapped, further reduces the axial dimension of the harmonic reducer device 100b, and further contributes to the miniaturization development of the harmonic reducer device 100b.

In the present embodiment, the projection overlap ratio of the power output end of the wave generator 20b and the stop bearing 40b on the axis of the sleeve 21b ranges from 0.1 to 1. Specifically, the projection overlap ratio may be 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9. The term "projected overlapping ratio" as used herein means, in a cross section parallel to the axial direction of the sleeve 21b, the definition: a axial length of the stop bearing 40b coinciding with a projection of the power take-off end of the wave generator 20b on the axis of the sleeve 21 b; b axial length of the stopper bearing 40B or axial length of the power output end of the wave generator 20B; c is the projection overlap ratio; where C = a/B, i.e. the projection overlap ratio C is equal to the ratio of a to B.

Preferably, the projection overlap ratio of the power output end of the wave generator and the stop bearing on the axis of the sleeve is in the range of 0.5-0.9.

The research and development personnel, under the guidance of the idea of overlapping the power take-off of the wave generator 20b with the projection of the stop bearing 40b on the axis of the sleeve 21b, continuously study and test, sample the finished product, test, and unexpectedly found in a large number of samples that "the overlap ratio of the projection of the power take-off of the wave generator and the stop bearing on the axis of the sleeve is in the range of 0.5-0.9", not only made a greater contribution in the axial dimension, but also well guaranteed in the product reliability.

The inner ring surface of the sleeve 21b is provided with a second step 24b; one side of the stop bearing 40b abuts against the second step 24b, and the other side indirectly abuts against the cup bottom 12b of the flexible gear 10 b. The second step 24b is formed by increasing the inner diameter of the sleeve 21b at a position corresponding to the second stopper structure 40b of the sleeve 21b.

The harmonic reducer unit 100b further includes an output shaft 80b fixedly connected to the inner race 72b of the output bearing 70b, with the stopper bearing 40b being located between the output shaft 80b and the sleeve 21b. In designing the harmonic reducer apparatus 100b, the inertial thinking is to arrange the stop bearing 40b at the periphery of the sleeve 21b, and it is not thought to arrange the stop bearing 40b between the sleeve 21b and the output shaft 80b, but the present invention proposes a completely new design idea, in which the stop bearing 40b is directly arranged between the sleeve 21b and the output shaft 80b, and the stop bearing 40b extends below the power output end of the wave generator 20b, and the sleeve 21b is arranged between the stop bearing 40b and the power output end of the wave generator 20b. The sleeve 21b and the output shaft 80b radially limit the stop bearing 40b, and no other limit structure is required to be additionally arranged.

The harmonic reducer device 100b further includes a washer 81b disposed between the cup bottom portion 12b of the flexspline 10b and the stopper bearing 40b. The gasket 81b has a sheet shape. The washer 81b and the second step 24b perform axial bidirectional limiting on the stopper bearing 40b, and the sleeve 21b and the output shaft 80b perform radial limiting on the stopper bearing 40b, so that the stopper bearing 40b is limited in both axial and radial directions.

The washer 81b is in the form of a sheet, the washer 81b and the stopper bearing 40b do not overlap in the axial direction of the sleeve 21b, and the washer 81b and the stopper bearing 40b are fitted to the sleeve 21b side by side. Referring to fig. 2 again, the washer 81a in fig. 2 includes a radial connecting portion 82a and an axial ring portion 83a, and the stopper bearing 40b is radially limited by the radial connecting portion 82a, but in the present invention, the washer 81b only needs to be simply in a sheet shape, and does not need the radial connecting portion 82a, so that the structure is simpler, and the assembly is easy.

A mounting portion 82b is projected from an outer circumferential surface of the output shaft 80b, and the mounting portion 82b is fixed to the inner ring 72b of the output bearing 70b together with the cup bottom portion 12b of the flexspline 10 b. In the axial direction of the sleeve 21b, the stopper bearing 40b, the washer 81b, the cup bottom portion 12b of the flexspline 10b, the mounting portion 82b, and the inner race 72b of the output bearing 70b are closely arranged in this order, and no other component is provided in the middle. The inner race 72b of the output bearing 70b has a receiving groove 73b formed therein, and the mounting portion 82b is mounted in the receiving groove 73b.

The harmonic reducer device 100b further includes another end cover 93b located outside the output bearing 70b, the other end cover 93b being connected to the inner race 72b of the output bearing 70b. The outer side of the output bearing 70b here means the side of the output bearing 70b facing away from the rigid wheel 60b.

The other end cap 93b is a separate piece from the output shaft 80 b. A harness structure 1b is provided between one side of the other end cover 93b and the output shaft 80 b. The other end cover 93b and the output shaft 80b are provided as two independent parts, so that the inconvenience of processing and installation caused by the integral structure of the output shaft 80a and the second end cover 93a shown in fig. 2 is reduced, and the cost is reduced, and the wire harness structure 1b can be arranged between the other end cover 93b and the end part of the output shaft 80 b.

The other end cover 93b is provided with a connecting portion 94b protruding from a side close to the output bearing 70b, and the connecting portion 94b extends into the inner race 72b of the output bearing 70b and is close to the end of the output shaft 80 b. In the present embodiment, the harness structure 1b includes a pipe body 101b connected to the inside of the connecting portion 94b, and an elastic expansion portion 102b sleeved outside the pipe body 101 b. The tube 101b is through which the cable 103b passes. One end of the pipe body 101b extends into the output shaft 80b, and the other end is connected to the connection portion 94 b. The expansion part 102b is located between the pipe body 101b and the connection part 94 b.

In the present embodiment, the wave generator main body 22b includes an elliptical disk 25b formed on the sleeve 21b and a flexible bearing 26b attached to the elliptical disk 25 b. In other embodiments, the wave generator body 22b includes a swivel arm formed on the sleeve 21b and rollers mounted at opposite ends of the swivel arm; alternatively, the wave generator main body 22b includes a cam formed on the sleeve 21b and a flexible bearing 26b connected to the cam.

In this embodiment, the output bearing 70b is a bearing with an oil seal 95b, and it is not necessary to provide the oil seal 95a on the inner side of the second end cover 93a as in the harmonic reducer shown in fig. 2, and the oil seal 95a provided on the inner side of the second end cover 93a needs to be customized, which is relatively high in cost.

In summary, the harmonic reducer device 100b of the present invention is reduced in cost by approximately 20% as compared to the harmonic reducer 100a shown in fig. 2. The concrete expression is as follows:

1. the rigid gear 60a and the flexible gear 10a of the harmonic reducer 100a shown in fig. 2 need to be customized, while the harmonic reducer device 100b of the present invention only needs to adopt the standard components of the rigid gear 60b and the flexible gear 10b to meet the design requirements, so that the customization cost is reduced;

2. the roller bearing 70a of the harmonic reducer 100a shown in fig. 2 is a bearing without an oil seal, and the oil seal is customized and designed between the right end cover 93a and the roller bearing 70a, while the output bearing 70b with the oil seal 95b is adopted in the invention, so that no additional design is needed, and the customization cost is reduced;

3. in the harmonic reducer 100a shown in fig. 2, the component serving as the shroud 91b is the fixing plate 52a on the outer side of the first end cap 50a, and this fixing plate 52a exists as a separate component in fig. 2, which inevitably increases the number of components, requires an increase in inventory space, increases the inventory control types of components, and increases the number of machining processes and assembling processes, and of course, increases the cost, whereas in the present invention, the shroud 91b is connected to the outer end edge of the main body 92b and is integrated with the main body 92 b. The surrounding plate 91b does not exist as a separate part, but is integrated with the main body 92b of the end cover 90b, so that the number of parts can be reduced, the additional processing cost of the surrounding plate 91b as the separate part is reduced, the processing procedure and the assembling procedure of the surrounding plate 91b as the separate part are also reduced, and the cost of the harmonic reducer device 100b is saved to a certain extent;

4. in the harmonic reducer 100a shown in fig. 2, the output shaft 80a and the right end cover 93a are integrated, the entire volume of the components is large, and the right end cover 93a and the output shaft 80a are almost perpendicular to each other, which increases the processing cost virtually in terms of the processing difficulty.

The joint 204 further includes a drive motor 9 that inputs power to the sleeve 21b. The drive motor 9 is provided on one side of the harmonic reducer device 100b. The joint 204 further includes another bearing 101 sleeved on the sleeve 21b, and the driving motor 9 includes a rotor 91 sleeved on the sleeve 21b and a stator 92 engaged with the rotor 91. The other bearing 101 is located on the side of the rotor remote from the wave generator 20b. The other bearing 101 is located on the side of the rotor 91 remote from the other end cap 93 b.

The joint 204 further includes a mounting member 206 sleeved on the sleeve 21b. The mounting member 206 is located on the side of the motor 9 remote from the end cap 90b and serves to retain the other bearing 101.

An accommodating space 93 is formed between the stator 92 and the rotor 91 of the motor 9, and the other bearing 101 is located in the accommodating space 93 and does not occupy the axial space of the joint 204. The mounting member 206 includes a plate body 207 and a retainer ring 208 coupled to one side of the plate body 207. The retainer ring 208 and the sleeve 21b radially retain the other bearing 101. The outer circumferential surface of the sleeve 21b is formed with a third step 27b. The third step 27b and the plate 207 axially limit the other bearing 101. The limiting ring 208 extends into the accommodating space 93. An elastic member 95 is disposed between the other bearing 101 and the plate 207, and plays a role of shock absorption.

The joint 204 further includes a stopper 205 mounted to the sleeve 21b. The stopper 205 is located outside the mounting member 206. The mount 206 is located between the brake 205 and the motor 9. The outer peripheral portion 2b of the attachment 206 is interposed between the housing 94 of the motor 9 and the case 209 of the brake 205, thereby fixing the attachment 206.

The mounting member 206 utilizes the original gap between the existing motor and the brake to mount the other bearing 101, and by extending the limiting ring 208 into the accommodating space 93 of the motor 9, the outer peripheral portion 2b of the mounting member 206 is connected between the housing 94 of the motor 9 and the housing 209 of the brake 205 in a staggered manner, so that the axial dimension of the whole joint is not increased.

As described above, the harmonic reducer apparatus 100b is reduced in the axial dimension, and the radial dimension of the ring gear 60b is not changed, so that the harmonic reducer apparatus 100b is required to be further reduced in size, and the joint 204 to which the harmonic reducer apparatus 100b is applied is also further reduced in size. Further, the robot arm 201 to which such a miniaturized joint is applied is also more miniaturized. The robot 200 using such a robot arm is also more miniaturized.

Referring to fig. 10 and fig. 11, a harmonic reducer apparatus 100c according to a second embodiment of the present invention is substantially the same as the harmonic reducer apparatus 100b according to the first embodiment, except that:

the first stopping structure 30c includes a stopping member 31c sleeved on the sleeve 21c and rotating along with the rotation of the sleeve 21c and a sealing member 32c connected to the stopping member 31 c; the inner side surface of one end of the stop member 31c abuts against the first step 23c, and the outer side surface of one end of the sealing member 32c abuts against the surrounding plate 91c, so that the first stop structure 30c is limited between the first step 23c and the surrounding plate 91 c. The inner side surface here means a side close to the wave generator main body 22c, and the outer side surface means a side far from the wave generator main body 22 c. Here, the one end of the stopper 31c means the one end close to the sleeve 21c, and the one end of the seal 32c means the one end close to the apron 91c and far from the sleeve 21c.

The first stopper structure 30c is generally sheet-like. The overall axial dimension of the first stop structure 30c is less than the difference between the inner and outer diameters of the first stop structure 30 c. The seal 32c rotates together with the stopper 31c along with the sleeve 21c. A rotation pair is formed between the seal 32c and the apron 91c, and when the sleeve 21c rotates, one end outer edge of the seal 32c contacts with the apron 91c to form the rotation pair. The one end outer edge of the seal 32c is always in contact with the apron 91c when the seal 32c rotates, and a seal structure is formed at the contact portion between the seal 32c and the apron 91 c.

The stopper 31c has a ring shape. The stopper 31c includes a fixing portion 301c having a U-shaped cross section, an extending portion 302c extending away from the sleeve 21c from a side of the fixing portion 301c close to the wave generator main body 22c, and an inclined portion 303c extending obliquely away from the sleeve 21c and toward the apron 91c from a side edge of the extending portion 302c away from the sleeve 21c.

The seal 32c is annular. The sealing member 32c includes a stopper portion 320c fixed in the fixing portion 301c, and a contact portion 321c extending obliquely from a side of the stopper portion 320c away from the sleeve 21c and close to the shroud 91c toward the shroud 91 c. The contact portion 321c and the stopper portion 320c form an obtuse angle.

The stopper 31c is a rigid member, and the seal member 32c is a flexible member. When the first stopping structure 30c rotates along with the sleeve 21c, the contact portion 321c and the enclosing plate 91c are always pressed to be in close contact, so that the limiting effect is achieved, and the sealing effect is also achieved.

Referring to fig. 12 and 13, a harmonic reducer apparatus 100d according to a third embodiment of the present invention is substantially the same as the harmonic reducer apparatus 100b according to the first embodiment, except that:

the first stopping structure 30d sleeved on the sleeve 21d is directly formed on the end cover 90d, and the axial stopping function is not realized by separate parts, so that the number of parts is reduced.

In the third embodiment, the first stop structure 30d is formed directly on the shroud 91 d. The first step is no longer required for limiting. The first stop structure 30d includes a connector ring 92d connected to a side of the shroud 91d adjacent the sleeve 21d, the connector ring 92d being in surface contact with the outer annular surface of the sleeve 21 d.

A seal structure 33d is formed between the connection ring 92d and the outer circumferential surface of the sleeve 21 d. The sealing structure 33d has a ring groove 34d formed in the contact surface between the connection ring 92d and the sleeve 21 d. The ring groove 34d includes two groove wall surfaces 36d and a groove bottom surface 37d connecting the two groove wall surfaces 36 d. A corner 38d is formed between the groove bottom surface 37d and each groove wall surface 36 d. The arrangement is such that even if the lubricant oil is going to flow out, the lubricant oil must pass through the two groove wall surfaces 36d, the one groove bottom surface 37d and the two corners 38d, and the long path finally prevents the lubricant oil from flowing out, so as to achieve the purposes of sealing and leakage prevention.

The annular groove 34d may be provided in plural numbers, for example, 1, 2, 3, etc., and in the case of reducing the axial dimension, the number of the annular grooves 34d may be set as appropriate.

In the present embodiment, the use of the first positioning bearing 30a of the harmonic reducer 100a shown in fig. 2 is eliminated, and the dimension of the first stopper structure 30d in the axial direction is smaller than the sum of the axial dimensions of the fixing plate 52a and the first positioning bearing 30a of the harmonic reducer 100a shown in fig. 2.

In the present embodiment, the connection ring 92d may extend toward the motor 9 d. It is understood that, in order to further reduce the axial dimension, the connection ring 92d may extend into the accommodation space 93d between the stator 921d and the rotor 911d of the motor 9 d.

Referring to fig. 14, fig. 14 is a comparison diagram of the harmonic reducer device 100d according to the third embodiment of the present invention and the harmonic reducer 100a of fig. 2 in the axial dimension, and it can be seen from the diagram that, under the same radial dimension L of the

rigid wheels

60d, 60a, the axial dimension is significantly reduced, specifically, the distance between the two is measured by taking the line W as a reference, and taking the element having the function of limiting the left side of the first stop structure 30d as a starting point (for fig. 2, the fixed plate 52a as a starting point, for fig. 14, the left side of the first stop structure 30d itself as a starting point), and taking the cup bottom 12d of the flexible wheel as an end point, and A1 is significantly smaller than A2, and the harmonic reducer device 100d according to the embodiment of the present invention is significantly reduced in the axial dimension compared with the harmonic reducer 100a of fig. 2. In the present example, a reduction of 5mm to 13mm is specified. Preferably, it is reduced by 8mm to 10mm.

In the first, second and third examples, three different solutions of the first stopping structure are provided, and in other embodiments, the first stopping structure may be another supporting structure such as a bushing.

In the present embodiment, the concept of the stopper means a receiving state, and does not necessarily have to be always in a contact state, and may be a stopper when the stopper is received in the moving direction. In other embodiments, the stop may function as a seal and/or a location, meaning a stationary location.

Referring to fig. 15, a harmonic reducer apparatus 100e according to a fourth embodiment of the present invention is substantially the same as the harmonic reducer apparatus 100b according to the first embodiment, except that:

the other end cap 93e is integral with the output shaft 80 e. The mounting portion 82b is not provided on the output shaft 80e, and the receiving groove 73b does not need to be provided in the inner race 72e of the output bearing 70 e. The cup bottom 12e of the flexspline 10e is directly fixed to the inner race 72e of the output bearing 70 e. The mounting portion 82b is not provided between the cup bottom portion 12e of the flexspline 10e and the inner race 72e of the output bearing 70 e. The cup bottom 12e of the flexspline 10e is in direct contact with the inner race 72e of the output bearing 70 e. The output shaft 80e is fixed to the inner race 72e of the output bearing 70e by fixing the other end cover 93e to the inner race 72e of the output bearing 70 e.

Referring to fig. 16, a harmonic reducer apparatus 100f according to a fifth embodiment of the present invention is substantially the same as the harmonic reducer apparatus 100c according to the second embodiment, and the difference therebetween is the same as the harmonic reducer apparatus 100e according to the fourth embodiment of the present invention and the harmonic reducer apparatus 100b according to the first embodiment, that is, the other end cover 93f is integrated with the output shaft 80 f. The output shaft 80f is no longer provided with a mounting portion, and the inner race 72f of the output bearing 70f is also not provided with a receiving groove. The cup bottom 12f of the flexspline 10f is directly fixed to the inner race 72f of the output bearing 70 f. No mounting portion is provided between the cup bottom portion 12f of the flexspline 10f and the inner race 72f of the output bearing 70 f. The cup bottom 12f of the flexspline 10f directly contacts the inner race 72f of the output bearing 70 f. The output shaft 80f is fixed to the inner race 72f of the output bearing 70f by fixing the other end cover 93f to the inner race 72f of the output bearing 70 f.

Referring to fig. 17, a harmonic reducer device 100g according to a sixth embodiment of the present invention is substantially the same as the harmonic reducer device 100d according to the third embodiment, and the difference is the same as the harmonic reducer device 100e according to the fourth embodiment of the present invention and the harmonic reducer device 100b according to the first embodiment, that is, the other end cover 93g is integrated with the output shaft 80 g. The output shaft 80g is not provided with a mounting portion, and the inner ring 72g of the output bearing 70g is not provided with an accommodating groove. The cup bottom 12g of the flexspline 10g is directly fixed to the inner race 72g of the output bearing 70 g. No mounting portion is provided between the cup bottom portion 12g of the flexspline 10g and the inner ring 72g of the output bearing 70 g. The cup bottom 12g of the flexspline 10g directly contacts the inner race 72g of the output bearing 70 g. The output shaft 80g is fixed to the inner ring 72g of the output bearing 70g by fixing the other end cover 93g to the inner ring 72g of the output bearing 70 g.

In the first to sixth embodiments described above, at least 2 points contributing to the reduction in the axial dimension of the harmonic reducer apparatus, specifically:

1. the first stop structure does not adopt a bearing structure, but adopts the

first stop structures

30b, 30c, 30d described in the above embodiments, and the axial dimension of the

first stop structures

30b, 30c, 30d is made smaller than that of a conventional bearing by the structural design thereof.

2. The projection of the power output end of the wave generator and the second stop structure on the axis of the sleeve at least partially overlaps.

It will be appreciated that in other embodiments, the harmonic reducer assembly is contemplated to be modified at point 2, without excessive modification at point 1, and again with a bearing arrangement. Specifically, the seventh embodiment, the eighth embodiment, and the ninth embodiment in the following description may be referred to.

Referring to fig. 18, a harmonic reducer apparatus 100h according to a seventh embodiment of the present invention is substantially the same as the harmonic reducer apparatus 100b according to the first embodiment, except that:

unlike the first embodiment, there is no need for a further bearing 101 between the brake 205 and the motor 9, nor of course the mounting 206, but rather the first stop arrangement 30h is of a bearing arrangement. Specifically, a stopper bearing 30h is provided between the shroud 91h and the first step 23 h. Due to the presence of the further bearing 101 and the mounting 206, the mounting 206 may take up axial length space, resulting in that the axial length of the harmonic reducer device cannot be further reduced in terms of mounting problems of the further bearing 101. In the seventh embodiment, the other bearing 101 and the mount 206 are eliminated, further reducing the axial length of the harmonic reducer apparatus.

In the seventh embodiment, the first stop structure 30h is a bearing structure, and plays a supporting role together with the second stop structure, so that the other bearing 101 and the mounting member 206 are eliminated.

Referring to fig. 21, fig. 21 is a comparison view of the harmonic reducer device 100b according to the first embodiment of the present invention and the harmonic reducer device 100h according to the seventh embodiment of the present invention shown in fig. 18, in which three lines are shown, the first line is a line E, the line E is a common starting line of the two

harmonic reducer devices

100b and 100h on the rightmost side, the second line is a line F on which the end face of the brake 205 on the rightmost side of the harmonic reducer device 100b according to the first embodiment is located, and the third line is a line G on which the end face of the brake 205 on the rightmost side of the harmonic reducer device 100h according to the seventh embodiment is located. The perpendicular distance from line E to line F is denoted by B1, and the perpendicular distance from line E to line G is denoted by B2, B1 being significantly greater than B2, it can be seen that the seventh embodiment provides a harmonic reducer apparatus 100h having a significantly reduced axial dimension as compared to the harmonic reducer apparatus 100B of the first embodiment. In the seventh embodiment, the reduction is specifically 5mm to 7mm. Preferably, it is reduced by 6mm to 7mm.

Further, an elastic member 95h is disposed between the stopper bearing 30h and the shroud 91h, and plays a role in damping vibration. One end of the elastic member 95h abuts against the surrounding plate 91h, and the other end abuts against the stop bearing 30h. The elastic member 95h is sandwiched between the enclosing plate 91h and the first stopping structure 30h. Specifically, the inner ring of the stopper bearing 30h is fitted around the outer circumferential surface of the sleeve, and rotates together with the sleeve. The other end of the elastic member 95h abuts against the outer ring of the stopper bearing 30h. In the present embodiment, the elastic member 95h is a wave spring. In other embodiments, the resilient member 95h can be other structures, such as a spring, a resilient washer, or the like.

Further, the shroud 91h extends into an accommodating space 93h formed between a stator 92h and a rotor 94h of the motor 9h. To further reduce the axial dimension. The surrounding plate 91h extends into the accommodating space 93h, so that the end cover forms a convex hull 96h protruding towards the accommodating space 93h, a cavity 97h is formed in the end cover corresponding to the convex hull 96h, and the stop bearing 30h and the elastic piece 95h are located in the cavity 97 h. The stopper bearing 30h and the elastic member 95h are sandwiched between the shroud plate 91h and the first step 23 h.

Referring to fig. 19, a harmonic reducer apparatus 100i according to an eighth embodiment of the present invention is substantially the same as the harmonic reducer apparatus 100h according to the seventh embodiment, and the difference therebetween is:

the other end cap 93i is integral with the output shaft 80 i. The output shaft 80i is not provided with a mounting portion, and the inner ring 72i of the output bearing 70i is not provided with an accommodating groove. The cup bottom 12i of the flexspline 10i is directly fixed to the inner race 72i of the output bearing 70 i. No mounting portion is provided between the cup bottom portion 12i of the flexspline 10i and the inner ring 72i of the output bearing 70 i. The cup bottom 12i of the flexspline 10i directly contacts the inner race 72i of the output bearing 70 i. The output shaft 80i is fixed to the inner ring 72i of the output bearing 70i by fixing the other end cover 93i to the inner ring 72i of the output bearing 70 i.

Referring to fig. 20, a harmonic reducer apparatus 100k according to a ninth embodiment of the present invention is substantially the same as the harmonic reducer apparatus 100b according to the first embodiment, except that:

the first stopper structure 30k adopts a bearing structure, and the surrounding plate 91b of the first embodiment is not provided; the end cap 90k extends into the receiving space 98k formed between the stator 92k and the rotor 91k of the motor 9k through a protruding ring portion 910 k.

The first stopper structure 30k is located within the raised ring portion 910 k. A locking ring 920k is provided between the first stop structure 30k and the rotor 91k of the motor 9 k. The first stopper structure 30k is located between the first step 23k and the retaining ring 920k at the upper axial limit of the sleeve 21 k. The first stopper structure 30k is confined between the projected ring portion 910k and the output shaft 80k in the radial direction of the sleeve 21 k.

The first stopper structure 30k extends between the stator 92k and the rotor 91 k. The second stop structure 40k replaces the bearing with a seal 40k. The seal 40k is sandwiched between the inner annular surface of the sleeve 21k and the output shaft 80 k. The seal 40k is in surface contact with the output shaft 80 k. A sealing structure is formed at the contact surface. The seal structure includes at least one annular groove 34k opening in the contact surface of the seal member 40k. In the present embodiment, the annular groove 34k is provided in plural, and a labyrinth seal structure is formed on the contact surface.

The seal 40k bears on one side against the second step 24k and on the other side indirectly or directly against the cup bottom 12k of the flexspline 10 k. A gasket (not shown) may be provided between the seal 40k and the cup bottom 12k of the flexspline 10k such that the other side of the seal 40k abuts against the cup bottom 12k of the flexspline 10k through the gasket.

The first stop arrangement 30k and the further bearing 101k are both located on the same side of the wave generator body 22 k.

In the ninth embodiment, the output shaft 80k is provided separately from the other end cover 93k as shown in the first embodiment, and in other embodiments, the output shaft 80k and the other end cover 93k may be integrated as shown in the fourth embodiment.

Referring to fig. 22, a harmonic reducer apparatus 100n according to a tenth embodiment of the present invention is substantially the same as the harmonic reducer apparatus 100h according to the seventh embodiment, except that: another bearing 101n and mount 206n provided between the brake 205n and the motor 9n remain. The structure of the mount 206n may be the same as that of the mount of the harmonic reducer apparatus provided in the first embodiment, and will not be described in detail. The structure of the mounting element 206n may also be slightly changed, and referring to fig. 22 in particular, the mounting element 206n includes a plate body 207n and a limit ring 208n connected to one side of the plate body 207n, a fixing sleeve 211n is sleeved on the outer side of the sleeve 21n, and the limit ring 208n and the fixing sleeve 211n limit the other bearing 101n in the radial direction. A third step 212n is formed on the outer annular surface of the fixing sleeve 211n, and the third step 212n and the plate body 207n axially limit the other bearing 101 n. The outer periphery of the mounting member 206n is secured to the outer shell of the overall joint. Specifically, the outer peripheral edge of the mounting member 206n is sandwiched between the motor housing 94n and the brake fixing seat 209 n. The other bearing 101n is at least partially located in the accommodating space 93 n.

Referring to fig. 23 and 24, fig. 23 is a perspective view of a joint 204h of a robot according to an embodiment of the present disclosure, to which a harmonic reducer apparatus 100h according to a seventh embodiment is applied. In addition to the structural differences with respect to the joint 204 to which the harmonic reducer device of the first embodiment is applied, the following differences (hereinafter, referred to as differences) are also provided:

the joint 204h further includes a motor-side encoder 2041. The motor-end encoder 2041 is sleeved on the sleeve 21h, and a part of the motor-end encoder 2041 is located inside the housing 209h of the brake 205h, and another part is located outside the housing 209h of the brake 205 h. The motor-end encoder 2041 does not take up axial space of the joint 204 h. The sleeve 21h is a separate body extending from the second stop structure 40h to the motor end encoder 2041 and beyond the motor end encoder 2041. The sleeve 21h is a separate integral component, which makes the assembly easier and reduces the number of parts. The entire harmonic reducer apparatus 100h is simple in structure. Of course, the structure of the entire joint 204h is also simple.

The joint 204h further includes a servo driver power board 2042, the servo driver power board 2042 is supported on a housing 209h (the housing 209h may also be called a brake fixing base 209h for fixing the brake 205 h) of the brake 205h, and a gap is left between the servo driver power board 2042 and the brake fixing base 209h to avoid each component on the servo driver power board 2042. The output shaft 80h passes through the servo driver power plate 2042.

The joint 204h also includes a load side encoder 2043. The load-side encoder 2043 is sleeved on the output shaft 80h and is located between the servo driver power board 2042 and the output shaft 80 h. The load side encoder 2043 does not occupy the axial space of the joint 204 h.

The joint 204h further includes a servo driver control board 2044 supported on the servo driver power board 2042. The servo driver control board 2044 is spaced apart from the servo driver power board 2042.

The joint 204h further includes a cable fixing plate 2045 through which the cable passes within the output shaft 80h and is fixed by the cable fixing plate 2045. The cable fixing plate 2045 is fixed outside the servo driver control board 2044 at intervals. The cable fixing plate 2045, the servo driver power plate 2042 and the servo driver control plate 2044 are arranged at intervals.

In the extending direction of the sleeve 21h, the brake fixing seat 209h, the servo driver power board 2042 and the servo driver control board 2044 are sequentially arranged at intervals.

The above-described "description of the difference" is also applicable to the joint or the robot having the harmonic reducer device provided in the first to sixth, eighth to tenth embodiments.

Some additional details need to be added (hereinafter referred to as additional description) here, as follows:

the first stop structure 30h and the second stop structure 40h are respectively located on opposite sides of the sleeve 21h, specifically, the first stop structure 30h is located on the outer side of the sleeve 21h, and the second stop structure 40h is located on the inner side of the sleeve 21h and between the sleeve 21h and the output shaft 80 h.

The sleeve 21h is a separate component. A first stop 30h, a second stop 40h and an electric motor 9h are arranged over the extension of the sleeve 21 h. Further, a stopper 205h and a motor-end encoder 2041 are also disposed on the extension length of the sleeve 21 h.

The joint 204h is used as an independent module, and a simple and convenient design idea is provided for installation and structural arrangement of the whole mechanical arm. In addition, the size of the joint of this application can reduce on axial dimensions for the joint of the harmonic speed reducer ware of using cup type flexbile gear for the joint of an independent module obtains bigger advantage, and short and small is bold, and market competition is strong. More space is also provided for the housing design of the robot arm.

It is to be understood that the above supplementary description is equally applicable to a joint or a robot having the harmonic reducer device provided in the first to sixth, eighth to tenth embodiments.

Referring to fig. 25, the joint 204h is a small-sized independent module, and when the module is installed in the whole outer casing 2001 of the robot, the outer casing 2001 can be smoothly transited at the joint turning 2002, and the smooth transition does not make the whole robot become heavy or heavy at the turning 2002. Of course, the rounded transition structure of the outer housing 2001 is equally applicable to either embodiment.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalents or improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A harmonic reducer device, characterized in that: harmonic speed reducer device include cupped flexbile gear, with flexbile gear engaged with rigid wheel and wave generator, the wave generator including supply power input's sleeve and set up in on the sleeve and make under telescopic rotation the flexbile gear takes place radial deformation in order to change the flexbile gear with the wave generator main part of rigid wheel meshing position, harmonic speed reducer device is still including the end cover and the output bearing of relative setting, harmonic speed reducer device still includes right the sleeve carries out first backstop structure and the second backstop structure of backstop, the power take off end of wave generator with the second backstop structure is in projection on the telescopic axis is at least partly overlaps.

2. The harmonic reducer apparatus of claim 1 wherein: the projection overlapping rate range of the power output end of the wave generator and the second stopping structure on the axis of the sleeve is 0.1-1.

3. The harmonic reducer apparatus of claim 1 wherein: the projection overlapping rate of the power output end of the wave generator and the second stopping structure on the axis of the sleeve ranges from 0.5 to 0.9.

4. The harmonic reducer apparatus of claim 1 wherein: the second stop structure is a stop bearing.

5. The harmonic reducer apparatus of claim 1 wherein: the harmonic reducer device further comprises an output shaft fixedly connected with the inner ring of the output bearing, and the second stop structure is located between the output shaft and the sleeve.

6. The harmonic reducer apparatus of claim 1 wherein: the first stopping structure is of a bearing structure and is sleeved outside the sleeve.

7. The harmonic reducer apparatus of claim 1 wherein: a gap is formed between the sleeve and the end cover, and the first stopping structure seals the gap.

8. The harmonic reducer apparatus of claim 1 wherein: the axial dimension of the first stop structure is less than the difference between the inner and outer diameters of the first stop structure.

9. The harmonic reducer apparatus of claim 1 wherein: the first stopping structure and the second stopping structure perform axial bidirectional stopping on the sleeve.

10. The harmonic reducer apparatus of claim 1 wherein: the outer ring surface of the sleeve is provided with a first step, the outer side surface of the end cover is provided with a surrounding plate, and the first stopping structure is arranged between the first step and the surrounding plate.

11. A harmonic reducer apparatus as defined in any of claims 1-9 in which: the first stopping structure adopts a bearing structure, and an elastic piece is arranged between the end cover and the first stopping structure.

12. The harmonic reducer apparatus of claim 11 wherein: and a coaming is formed on the outer side surface of the end cover, and the elastic piece is clamped between the coaming and the first stopping structure.

13. The harmonic reducer apparatus of claim 12, wherein: the inner ring of the first stopping structure is sleeved on the peripheral surface of the sleeve and rotates along with the sleeve; one end of the elastic piece is abutted against the enclosing plate, and the other end of the elastic piece is abutted against the outer ring of the first stop structure.

14. The harmonic reducer apparatus of claim 10 wherein: the end cover comprises a main body, the rigid wheel is fixed between the inner end face of the main body and the outer ring of the output bearing, and the coaming is connected to the outer end edge of the main body and is integrated with the main body.

15. The harmonic reducer apparatus of claim 5 wherein: the outer ring surface of the output shaft is convexly provided with an installation part, and the installation part and the cup bottom of the flexible gear are fixed on the inner ring of the output bearing together.

16. The harmonic reducer apparatus of claim 4 wherein: a second step is arranged on the inner ring surface of the sleeve; one side of the stop bearing abuts against the second step, the other side of the stop bearing indirectly abuts against the bottom of the flexible gear, and the outer ring of the stop bearing abuts against the second step.

17. A harmonic reducer apparatus as defined in any of claims 1-4 and 6-10 wherein: the harmonic reducer device further comprises an output shaft fixedly connected with the inner ring of the output bearing and another end cover located on the outer side of the output bearing, and the other end cover is connected to the inner ring of the output bearing.

18. The harmonic reducer apparatus of claim 17 wherein: the other end cover and the output shaft are two independent parts, and a wire harness structure is arranged between the other end cover and the output shaft.

19. A harmonic reducer apparatus as defined in any of claims 1-10 and 15-16 wherein: the wave generator main body comprises a rotating arm formed on the sleeve and rollers arranged at two opposite ends of the rotating arm; or, the wave generator body comprises a cam formed on the sleeve and a flexible bearing connected to the cam; alternatively, the wave generator main body comprises an elliptical disk formed on the sleeve and a flexible bearing connected to the elliptical disk.

20. A joint, characterized by: the joint comprises a harmonic reducer assembly according to any of claims 1-19 and a drive motor for power input to the sleeve.

21. A joint according to claim 20, wherein: the joint further comprises another bearing sleeved on the sleeve and a mounting part for limiting the other bearing, an accommodating space is formed between a stator and a rotor of the motor, and at least part of the other bearing is located in the accommodating space.

22. The joint of claim 21, wherein: the mounting piece comprises a plate body and a limiting ring connected to one side of the plate body, the limiting ring and the sleeve are used for radially limiting the other bearing, a third step is formed on the outer annular surface of the sleeve, and the third step and the plate body are used for axially limiting the other bearing.

23. The joint of claim 21, wherein: the mounting piece comprises a plate body and a limiting ring connected to one side of the plate body, a fixing sleeve is sleeved on the outer side of the sleeve, the limiting ring and the fixing sleeve are used for radially limiting the other bearing, a third step is formed on the outer ring surface of the fixing sleeve, and the third step and the plate body are used for axially limiting the other bearing.

24. A joint according to any one of claims 20 to 23, wherein: the joint further comprises a brake arranged on the sleeve, a brake fixing seat for fixing the brake, a servo driver power plate and a servo driver control plate; in the extending direction of the sleeve, the brake fixing seat, the servo driver power board and the servo driver control board are sequentially arranged at intervals.

25. A joint according to claim 24, wherein: the joint further comprises a motor end encoder sleeved on the sleeve and a load end encoder sleeved on the output shaft, and the motor end encoder and the load end encoder do not occupy the axial space of the joint.

26. A robotic arm, characterized by: the robot arm comprising a joint as claimed in any one of claims 20-23, the joint being present as a stand-alone module.

27. A robot, characterized by: the robot comprising a robotic arm as claimed in claim 26.

28. A robot as recited in claim 27, wherein: the robot comprises an outer shell, and the outer shell forms a smooth transition structure at the turning of the joint.