CN214352540U - Arm joint and arm - Google Patents

Abstract

The utility model discloses an arm joint and arm relates to arm technical field. The mechanical arm joint comprises a body, an end cover and a speed reducing mechanism. The body is provided with a mounting groove; the end cover is arranged at the opening of the mounting groove, a mounting cavity is enclosed by the end cover and the mounting groove, and the end cover is provided with a through hole; the speed reducing mechanism is arranged in the mounting cavity, the output end of the speed reducing mechanism is connected with the body, and the input shaft of the speed reducing mechanism extends out of the mounting cavity through the through hole. This arm joint is through all setting up reduction gears on a arm joint in order to avoid the assembly mistake and improve assembly efficiency.

Description

Arm joint and arm

Technical Field

The utility model relates to an arm technical field especially relates to a arm joint and arm.

Background

With the progress of the mechatronic technology and the vigorous development of artificial intelligence wave, industrial products are developed towards the direction of intellectualization, systematization, miniaturization, modularization and man-machine cooperation. In an automated production line, the assembly and transfer of the parts are completed by a robot arm. The mechanical arm has the development trend of high refinement, modularization, light weight and multiple degrees of freedom. A robot arm generally includes a plurality of robot joints connected in series, and a gripper, a cutting tool, a detector, and the like may be mounted on the robot joint at the end of the robot arm to perform various motions. The mechanical arm joints are provided with speed reducing mechanisms connected with the driving device, and in the prior art, the speed reducing mechanisms are separately arranged in two adjacent mechanical arm joints and then assembled. This makes the operation difficult in the production process, and the reduction mechanism is liable to be erroneously assembled, and the assembly efficiency is low.

In view of the above problems, it is necessary to develop a robot joint and a robot to solve the problems of easy assembly error and low assembly efficiency caused by the sub-assembly of the speed reduction mechanism components.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a mechanical arm joint and arm, through with all setting up the reduction gears on a mechanical arm joint in order to avoid assembly mistake and improve assembly efficiency.

To achieve the purpose, the utility model adopts the following technical proposal:

a robotic arm joint, comprising:

the body is provided with a mounting groove;

the end cover is arranged at the opening of the mounting groove, a mounting cavity is defined by the end cover and the mounting groove, and the end cover is provided with a through hole;

the speed reducing mechanism is arranged in the mounting cavity, the output end of the speed reducing mechanism is connected with the body, and the input shaft of the speed reducing mechanism extends out of the mounting cavity through the through hole.

Preferably, the reduction gears is the harmonic reduction gear, the harmonic reduction gear include the input shaft, set up in wave generator on the input shaft, the cover is located the outer flexbile gear of wave generator and can with the steel wheel of flexbile gear meshing, the steel wheel respectively with the body with the end cover is fixed.

Preferably, the end cover comprises a cover plate and an annular flange arranged around the edge of the cover plate, the inner side surface of the flange is a first positioning surface, the first positioning surface is abutted to the outer peripheral surface of the steel wheel, and the cover plate is abutted to the end surface of the steel wheel.

Preferably, the end cap is an interference fit with the steel wheel.

Preferably, the device further comprises a guide assembly, wherein the guide assembly comprises:

the first bearing is arranged on the bottom surface of the mounting groove;

the second bearing is arranged in the through hole;

one end of the input shaft extending into the mounting cavity is rotatably connected with the body through the first bearing, and the input shaft is rotatably connected with the end cover through the second bearing.

Preferably, the positioning device further comprises a positioning assembly, wherein the positioning assembly comprises:

the first bearing cover is arranged on the end face of one side, extending into the mounting cavity, of the input shaft and is abutted against the inner ring of the first bearing;

the second bearing cover is sleeved outside the input shaft and connected with the end cover, and the second bearing is positioned between the second bearing cover and the end cover;

the wave generator is respectively abutted against the inner rings of the first bearing and the second bearing.

Preferably, the side wall of the through hole is a second positioning surface, and the side wall of the outer ring of the second bearing is abutted to the second positioning surface.

Preferably, a first sealing ring is arranged between the end face of the steel wheel and the bottom face of the mounting groove, and a second sealing ring is arranged between the end cover and the steel wheel.

Preferably, an oil seal is arranged between the input shaft and the end cover.

A mechanical arm comprises the mechanical arm joint.

Preferably, the mechanical arm comprises at least two mechanical arm joints which are connected in sequence, an annular boss is convexly arranged on the outer side of the end cover, the side wall of the boss is a third positioning surface, and in two adjacent mechanical arm joints, one of the mechanical arm joints is buckled on the other mechanical arm joint on the boss and is abutted against the third positioning surface.

The utility model has the advantages that:

the utility model provides a mechanical arm joint and mechanical arm. In this arm joint, reduction gears sets up in the mounting groove of body to fix the part in the reduction gears through the end cover, make whole arm joint can assemble with another arm joint again after the assembly is accomplished, avoid assembling the reduction gears branch station, produce the condition of reduction gears assembly error. Meanwhile, the mechanical arm joint is assembled in a modularized mode, and the production efficiency is greatly improved.

Drawings

Fig. 1 is a schematic structural diagram of a robot arm provided by the present invention;

fig. 2 is a front view of a robot arm joint provided by the present invention;

fig. 3 is a cross-sectional view taken at a-a of fig. 2 in accordance with the present invention;

fig. 4 is a schematic structural view of the body and the speed reducing mechanism provided by the present invention;

fig. 5 is a cross-sectional view of an end cap provided by the present invention.

1. A body; 2. an end cap; 3. a speed reduction mechanism; 4. a guide assembly; 5. a positioning assembly; 6. a shaft sleeve; 7. oil sealing; 8. a mechanical arm;

21. a through hole; 22. a first positioning surface; 23. a second seal ring; 24. a second positioning surface; 25. a third positioning surface; 31. a steel wheel; 32. a wave generator; 33. an input shaft; 41. a first bearing; 42. a second bearing; 51. a first bearing cover; 52. a second bearing cover; 81. a base; 82. a first mechanical arm joint; 83. a second mechanical arm joint; 84. a third mechanical arm joint; 85. and a fourth mechanical arm joint.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and intended to be used for explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplification of description, but do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Wherein the terms "first position" and "second position" are two different positions.

Unless expressly stated or limited otherwise, the terms "mounted," "connected," and "secured" are to be construed broadly and encompass, for example, both fixed and removable connections; can be mechanically or electrically connected; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meaning of the above terms in the present invention can be understood according to specific situations by those skilled in the art.

Unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may include the first feature being in direct contact with the second feature, or may include the first feature being in direct contact with the second feature but being in contact with the second feature by another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

The technical solution of the present invention is further explained by the following embodiments with reference to the accompanying drawings.

As shown in fig. 1, the present embodiment provides a robot arm 8, which includes a plurality of robot arm joints connected in sequence, where the end of the robot arm 8 is used to connect with an execution mechanism, and two adjacent robot arm joints are in transmission connection to implement multi-degree-of-freedom motion of the end of the robot arm 8.

Specifically, the mechanical arm 8 includes a base 81, a first mechanical arm joint 82, a second mechanical arm joint 83, a third mechanical arm joint 84 and a fourth mechanical arm joint 85, the first mechanical arm joint 82 on the base 81 can rotate around the Z axis, the first mechanical arm joint 82 can drive the second mechanical arm joint 83 to rotate around the X axis, the second mechanical arm joint 83 can drive the third mechanical arm joint 84 to rotate around the X axis, and the third mechanical arm joint 84 can drive the fourth mechanical arm joint 85 to rotate around the Z axis.

In two adjacent mechanical arm joints, the driven mechanical arm joint is in transmission connection with the output end of the other adjacent mechanical arm joint through an input shaft 33 of a speed reducing mechanism 3, and the speed reducing mechanism 3 can be a harmonic speed reducer or a planetary speed reducer.

Because the harmonic speed reducer has the advantage that the speed reduction ratio is high, the precision is high, can improve arm joint pivoted precision, and the harmonic speed reducer can realize very high speed reduction ratio with less volume, can reduce the space that arm joint took by a wide margin, so use in the arm joint in this embodiment is the harmonic speed reducer.

For the assembly of convenient arm 8, integrate reduction gears 3 in the arm joint that is driven in this embodiment for every arm joint's modularization degree is high, can assemble the arm joint back, and two adjacent arm joints of reassembling produce the problem that assembly error and assembly efficiency are low easily that leads to in two arm joints with 3 part partial shipment of reduction gears. In the present embodiment, the third robot joint 84 will be described as an example.

As shown in fig. 2 and 3, the robot joint includes a body 1, an end cap 2, and a speed reduction mechanism 3. Body 1 is provided with the mounting groove, and end cover 2 sets up in the opening part of mounting groove and relatively fixed with body 1, and end cover 2 encloses into the installation cavity with the mounting groove, and end cover 2 is provided with through-hole 21, and reduction gears 3 sets up in the installation cavity, and reduction gears 3's output and body 1 are connected, and reduction gears 3's input shaft 33 stretches out outside the installation cavity by through-hole 21.

All parts of the speed reducing mechanism 3 are mounted on the third mechanical arm joint 84 through the end cover 2, so that when the third mechanical arm joint 84 and the second mechanical arm joint 83 are assembled, the speed reducing mechanism 3 does not need to be detached firstly, and then the speed reducing mechanism 3 is mounted in the two mechanical arm joints respectively and then is assembled, but the speed reducing mechanism 3 can be completely assembled on the third mechanical arm joint 84, and then the second mechanical arm joint 83 is integrally assembled on the input shaft 33. This has the advantage that only the two mechanical arm joints need to be assembled with the mutually matching structures, and then the driving member needs to be in transmission connection with the input shaft 33 of the speed reducing mechanism 3. Compare through the part of reduction gears 3 with two arm joint connection, the condition that modular assembly greatly reduced like this and taken place assembly error has just improved production efficiency. And because the arm joint is heavier, and assembly structure is more complicated, and the assembly precision is difficult to master more, lead to 8 precision on the arm not high, can't be competent in the work that becomes more meticulous. The mechanical arm 8 is more convenient for replacing and maintaining the speed reducing mechanism 3.

Through setting up end cover 2, can improve the modularization degree of third arm joint 84, two arm joints of mutually supporting can assemble the back alone, assemble again, are favorable to the reasonable division of assembly line to improve assembly efficiency.

In addition, the modular design of the mechanical arm joint can be favorable for standardized production of the mechanical arm joint, so that the structure of the joint can be used for connection of various mechanical arms, the applicability of parts is greatly improved, large-scale production can be realized, and the production cost is reduced.

Preferably, the speed reduction mechanism 3 is a harmonic reducer, and includes an input shaft 33, a wave generator 32 disposed on the input shaft 33, a flexible gear sleeved outside the wave generator 32, and a steel wheel 31 capable of meshing with the flexible gear, wherein the steel wheel 31 is fixed to the body 1 and the end cap 2, respectively. When the input shaft 33 rotates, the wave generator 32 is driven to rotate to generate periodic elastic deformation waves to deform the flexible gear, the extending part of the flexible gear is meshed with the inner ring of the steel gear 31, the rest part of the flexible gear is separated from the steel gear 31, the tooth pitches of the flexible gear and the steel gear 31 are equal, the number of teeth of the flexible gear and the number of teeth of the steel gear 31 are small, the flexible gear and the steel gear 31 rotate relatively, when one of the flexible gear and the steel gear is fixed, the other flexible gear and the steel gear are used as output ends to output torque and rotating speed. In this embodiment, the steel wheel 31 is fixedly connected to the body 1 of the third mechanical arm joint 84 as a fixing member, and the rotation of the mechanical arm joint is realized by the rotation of the steel wheel 31.

It should be noted that any structure in the art may be adopted for the harmonic reducer, and the specific structure of the harmonic reducer and the connection relationship between the components are not described in detail in this embodiment.

It will be appreciated that the end cap 2 may also be fixedly connected directly to the body 1.

Preferably, the end cover 2 comprises a cover plate and an annular flange arranged around the edge of the cover plate, the inner side surface of the flange is a first positioning surface 22, the first positioning surface 22 abuts against the outer peripheral surface of the steel wheel 31, and the cover plate abuts against the end surface of the steel wheel 31. Through the cooperation of the first positioning surface 22 and the outer peripheral surface of the steel wheel 31, the precision of the third mechanical arm joint 84 can be improved, the input shaft 33 is more stable in rotation, the difficulty of the end cover 2 in the assembling process is reduced, and the working efficiency is greatly improved.

Preferably, the end cover 2 is in interference fit with the steel wheel 31, so that the assembly gap between the end cover 2 and the steel wheel 31 can be eliminated. In the running process of the speed reducing mechanism 3, the end cover 2 cannot be installed and loosened due to vibration caused by high-speed rotation of the input shaft 33, so that the track running precision of the mechanical arm 8 is improved, and meanwhile, noise is reduced. The reduction in the noise of the operation of the drive train can improve the competitiveness of the robot arm 8 in production.

Further, steel wheel 31 includes major diameter section and path section, and the major diameter section is close to body 1 inboard, path section and 2 interference fit of end cover. The steel wheel 31 can be fixedly connected with the body 1 through a bolt, and the bolt is screwed in from a step surface formed at the joint of the large-diameter section and the small-diameter section and is in threaded connection with the body 1.

Preferably, the third mechanical arm joint 84 further comprises a guide assembly 4 including a first bearing 41 and a second bearing 42. The first bearing 41 is arranged on the bottom surface of the mounting groove, the second bearing 42 is arranged in the through hole 21, one end of the input shaft 33 extending into the mounting cavity is rotatably connected with the body 1 through the first bearing 41, and the input shaft 33 is rotatably connected with the end cover 2 through the second bearing 42. The friction received when input shaft 33 rotates is reduced by the bearing, the loss in the transmission process is reduced, and the transmission efficiency is improved.

Preferably, the third mechanical arm joint 84 further comprises a positioning assembly 5, including a first bearing cover 51 and a second bearing cover 52. The first bearing cover 51 is arranged on the end face of one side of the input shaft 33, which extends into the mounting cavity, the first bearing cover 51 is abutted against the inner ring of the first bearing 41, the second bearing cover 52 is sleeved outside the input shaft 33 and is connected with the end cover 2, the second bearing 42 is positioned between the second bearing cover 52 and the end cover 2, and the wave generator 32 is respectively abutted against the inner rings of the first bearing 41 and the second bearing 42.

The second bearing cover 52 and the end cover 2 jointly fix the second bearing 42, the wave generator 32 abuts against the inner rings of the first bearing 41 and the second bearing 42, the three jointly rotate along with the input shaft 33, and the axial positioning of the whole structure is realized through the first bearing cover 51.

In other embodiments, the third mechanical arm joint 84 further comprises a bushing 6, the bushing 6 being disposed between the first gear and the wave generator 32 and the second gear and the wave generator 32. The sleeve 6 abuts against the inner ring of the first gear, the wave generator 32 and the inner ring of the second gear and rotates synchronously with the input shaft 33, and all the components are stably fixed.

In order to prevent the transmission efficiency from being reduced due to the relative sliding between the input shaft 33 and the wave generator 32, in the embodiment, the input shaft 33 is provided with a flat key, one part of the flat key is embedded in the input shaft 33, and the other part of the flat key is embedded in the wave generator 32, so that the synchronous rotation of the input shaft 33 and the wave generator 32 is ensured.

Wherein, be provided with first sealing washer between the bottom surface of the terminal surface of steel wheel 31 and mounting groove, be provided with second sealing washer 23 between end cover 2 and the steel wheel 31. The space enclosed by the end cover 2, the steel wheel 31 and the body 1 is divided into two oil cavities by the wave generator 32, and lubricating grease is filled in the two oil cavities and used for lubricating the first bearing 41 and the second bearing 42, so that abrasion is reduced.

In this embodiment, the end cover 2 is arranged to realize the modular design of the third mechanical arm joint 84, so that when the third mechanical arm joint 84 is detached from another mechanical arm in cooperation with the third mechanical arm joint, an oil cavity in the third mechanical arm joint 84 is always kept in a sealed state, and the leakage of lubricating grease is avoided.

Further, an oil seal 7 is provided between the input shaft 33 and the end cover 2 in order to prevent grease from leaking out when the two robot joints are removed for maintenance.

Preferably, the side wall of the through hole 21 of the end cover 2 is a second positioning surface 24, and the outer ring side wall of the second bearing 42 abuts against the second positioning surface 24. The second locating surface 24 is used to provide precision assurance for the position of the bearing of the second bearing 42 and the oil seal 7, so that the input shaft 33 is less sloshing during rotation, and precision is improved. Wherein, the second positioning surface 24 can be provided with two steps in a step shape and is used for being respectively abutted with the second bearing 42 and the outer ring of the oil seal 7.

Preferably, an annular boss is convexly arranged on the outer side of the end cover 2, the side wall of the boss is a third positioning surface 25, and in two adjacent mechanical arm joints, the body 1 of the second mechanical arm joint 83 is buckled on the boss of the third mechanical arm joint 84 and is abutted against the third positioning surface 25. The third positioning surface 25 can reduce the difficulty of the operator in assembling the mechanical arm 8, provides a reference for the assembly of the operator, greatly improves the assembly efficiency, and ensures the assembly precision.

In the assembling process of the mechanical arm joint, the assembling steps are as follows:

s1: the steel wheel 31 of the harmonic reducer is installed on the body 1 of the third mechanical arm joint 84 through screws;

s2: inserting the input shaft 33 through the second bearing 42, and inserting the second bearing 42 into the through hole 21 of the end cap 2 such that the outer surface of the second bearing 42 abuts against the second positioning surface 24;

s3: an outer race for fixing the second bearing 42 by mounting the second bearing cover 52 on the end cap 2 with screws;

s4: the wave generator 32 and the first bearing 41 are sequentially arranged on the input shaft 33, and a shaft sleeve 6 is respectively arranged between the second bearing 42 and the wave generator 32 and between the wave generator 32 and the first bearing 41;

s5: a first bearing cover 51 is installed on the input shaft 33 at one end of the first bearing 41 by using a screw, and the first bearing 41, the wave generator 32, the second bearing 42 and the two shaft sleeves 6 are tightly abutted in the axial direction of the input shaft 33;

s6: the end cover 2 is buckled on the steel wheel 31 and fixed through screws, and meanwhile, the first bearing 41 is fixed on the bottom surface of the body 1;

s7: an oil seal 7 is mounted between the input shaft 33 and the second locating surface 24 of the end cap 2.

In the assembling process of the third mechanical arm joint 84, except the steel wheel 31, other structures of the speed reducing mechanism 3 are assembled with the end cover 2 and then are arranged in the body 1, so that the installation, the disassembly and the replacement and the maintenance are convenient.

In some embodiments, the steel wheel 31 may also be installed on the end cover 2 together with other structures in the speed reducing mechanism 3, and then the end cover 2 and the speed reducing mechanism 3 are installed in the body 1, because the step surface of the steel wheel 31 is exposed out of the end cover 2, a bolt may be screwed into the step surface, so as to fix the steel wheel 31 and the body 1 by a screw.

It can be understood that the requirement of the mechanical arm 8 on the rotation precision of the input shaft 33 is high, and in the assembling process, the first positioning surface 22, the second positioning surface 24 and the third positioning surface 25 on the end cover 2 can well guarantee the precision, and the assembling difficulty is reduced. And the three positioning surfaces of the end cover 2 are circumferential surfaces and are coaxially arranged, so that the end cover can be machined by utilizing a lathe, the operation is simple and convenient, the coaxial precision of the three surfaces can be easily ensured, and the guarantee is provided for the high precision of subsequent assembly. And the coaxiality can help to reduce the vibration and noise caused by high-speed movement of a shafting in the operation process of the mechanical arm 8, reduce the vibration of a transmission system and reduce the shaking condition of the tail end of the robot, thereby improving the track operation precision of the robot. The reduction of the operating noise of the transmission system can improve the competitiveness of robot products.

Preferably, the second mechanical arm joint 83 is further provided with a rotating motor, and an output shaft of the rotating motor can drive the input shaft 33 to rotate. The input shaft 33 is driven to rotate by the rotating motor, the rotating speed is reduced by the speed reducing mechanism 3, the third mechanical arm joint 84 can be driven to rotate relative to the second mechanical arm joint 83, and the rotating angle of the two mechanical arm joints can be calculated by the rotating speed of the rotating motor and the speed reducing ratio of the speed reducing mechanism 3.

Preferably, the rotating electrical machine may drive the input shaft 33 to rotate through a gear train, and the drive to the input shaft 33 may also be accomplished by tensioning a belt over the output shaft and the input shaft 33.

The above description is only for the preferred embodiment of the present invention, and for those skilled in the art, there are variations on the detailed description and the application scope according to the idea of the present invention, and the content of the description should not be construed as a limitation to the present invention.

Claims (11)

1. A robot arm joint, comprising:

the device comprises a body (1), wherein a mounting groove is formed in the body (1);

the end cover (2) is arranged at an opening of the mounting groove, the end cover (2) and the mounting groove enclose a mounting cavity, and the end cover (2) is provided with a through hole (21);

reduction gears (3), reduction gears (3) set up in the installation cavity, the output of reduction gears (3) with body (1) is connected, input shaft (33) of reduction gears (3) by through-hole (21) stretch out outside the installation cavity.

2. The mechanical arm joint as claimed in claim 1, wherein the speed reducing mechanism (3) is a harmonic speed reducer, the harmonic speed reducer comprises the input shaft (33), a wave generator (32) arranged on the input shaft (33), a flexible gear sleeved outside the wave generator (32), and a steel gear (31) capable of being engaged with the flexible gear, and the steel gear (31) is fixed with the body (1) and the end cap (2) respectively.

3. The mechanical arm joint as recited in claim 2, wherein the end cover (2) comprises a cover plate and an annular flange arranged around the edge of the cover plate, the inner side surface of the flange is a first positioning surface (22), the first positioning surface (22) is abutted with the outer circumferential surface of the steel wheel (31), and the cover plate is abutted with the end surface of the steel wheel (31).

4. A robot arm joint according to claim 3, characterized in that the end cap (2) is an interference fit with the steel wheel (31).

5. The mechanical arm joint according to claim 2, further comprising a guide assembly (4), the guide assembly (4) comprising:

a first bearing (41), the first bearing (41) being disposed on a bottom surface of the mounting groove;

a second bearing (42), said second bearing (42) being disposed within said through hole (21);

one end of the input shaft (33) extending into the installation cavity is rotatably connected with the body (1) through the first bearing (41), and the input shaft (33) is rotatably connected with the end cover (2) through the second bearing (42).

6. The mechanical arm joint according to claim 5, further comprising a positioning assembly (5), the positioning assembly (5) comprising:

the first bearing cover (51) is arranged on one side end face, extending into the mounting cavity, of the input shaft (33), and the first bearing cover (51) is abutted with the inner ring of the first bearing (41);

the second bearing cover (52) is sleeved outside the input shaft (33) and connected with the end cover (2), and the second bearing (42) is positioned between the second bearing cover (52) and the end cover (2);

the wave generator (32) is in contact with inner rings of the first bearing (41) and the second bearing (42), respectively.

7. The mechanical arm joint as claimed in claim 5, wherein the side wall of the through hole (21) is a second positioning surface (24), and the outer ring side wall of the second bearing (42) abuts against the second positioning surface (24).

8. A mechanical arm joint as claimed in claim 2, wherein a first sealing ring is arranged between the end surface of the steel wheel (31) and the bottom surface of the mounting groove, and a second sealing ring (23) is arranged between the end cover (2) and the steel wheel (31).

9. A robot arm joint according to claim 1, characterized in that an oil seal (7) is provided between the input shaft (33) and the end cap (2).

10. A robot arm comprising a robot joint according to any of claims 1 to 9.

11. The mechanical arm according to claim 10, characterized in that the mechanical arm comprises at least two mechanical arm joints connected in sequence, an annular boss is convexly arranged on the outer side of the end cover (2), the side wall of the boss is a third positioning surface (25), and the body (1) in one of the two adjacent mechanical arm joints is buckled on the boss of the other mechanical arm joint and is abutted against the third positioning surface (25).

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