Axially compact joint module and joint structure

Abstract

The invention provides an axially compact joint module and a joint structure. The axially compact joint module comprises a harmonic assembly, wherein the harmonic assembly comprises a crossed roller bearing outer ring which is fixedly connected with a steel wheel, a crossed roller bearing inner ring which is fixedly connected with a hollow shaft, a flexible gear is meshed with the steel wheel, and the flexible gear is connected with a wave generator through a bearing; the motor assembly comprises a motor stator and a motor rotor which are coupled, a motor shaft is fixedly connected with the motor rotor, the meshing part of the flexible gear and the steel wheel extends into the motor shaft, and a small bearing is arranged between the inner circle of the motor shaft and the hollow shaft; the brake assembly comprises a brake rotating shaft and a brake cover plate, the brake rotating shaft is fixedly connected with the motor shaft, the brake cover plate is fixedly connected with the shell, and the outer circle of the motor shaft is connected with the shell through a large bearing and the brake cover plate in a matched mode. The meshing part of the flexible wheel and the steel wheel extends into the motor shaft and is overlapped in the axial size, the total length of the joint can be reduced by axially overlapping the small bearing and the large bearing, and the axial compactness of the joint module is improved.

Description

Technical Field

[0001] The present invention relates to the field of joint module structure design, and in particular to an axially compact joint module and a joint structure. Background Art

[0002] The joint module is a highly integrated robot joint component. It is generally composed of multiple key components such as motors (such as frameless torque motors), reducers (such as harmonic, planetary, roller screws, etc.), encoders, and drivers. As a key component of humanoid robots, the joint module largely determines the explosive power and load capacity of humanoid robots.

[0003] With the development of science and technology, higher requirements are placed on the structural design of robots, for example: greater space utilization is required.

[0004] The existing Chinese patent application document with publication number CN109366480A discloses a highly integrated mechatronic robot joint module, which includes a shell, a braking device, a hollow frameless motor, a harmonic reducer, a low-voltage DC drive and a corresponding PCB circuit board, and also includes an incremental encoder for measuring the input speed of the motor and an absolute encoder for measuring the output of the harmonic reducer; all rotating parts of the joint module are coaxially arranged and designed as a hollow mode for wiring.

[0005] The joint module in the prior art adopts a configuration in which the brake, motor and harmonic components are arranged side by side in sequence, which has the following defects:

[0006] 1. The motor shaft does not have double support, and the rotation stability is insufficient;

[0007] 2. The overall axial dimension of the joint is long and the joint is not compact enough. Summary of the invention

[0008] In view of the defects in the prior art, an object of the present invention is to provide an axially compact joint module and joint structure.

[0009] According to the present invention, an axially compact joint module includes a housing, a harmonic component, a motor component and a brake component, wherein the harmonic component, the motor component and the brake component are sequentially arranged along the axial direction of the housing;

[0010] The harmonic assembly includes a cross roller bearing, a steel wheel, a flexible wheel, a wave generator and a hollow shaft, the outer ring of the cross roller bearing is fixedly connected to the steel wheel, the inner ring of the cross roller bearing is fixedly connected to the hollow shaft, the flexible wheel is meshed with the steel wheel, and the flexible wheel is connected to the wave generator through a bearing;

[0011] The motor assembly includes a motor stator, a motor rotor and a motor shaft. The motor stator is coupled to the motor rotor, the motor shaft is fixedly connected to the motor rotor, the meshing part of the flexible wheel and the steel wheel extends into the motor shaft, and a small bearing is arranged between the inner circle of the motor shaft and the hollow shaft.

[0012] Preferably, the small bearing and the large bearing partially or completely overlap in the axial direction.

[0013] Preferably, a first concave cavity is formed on a side of the motor shaft close to the harmonic component, and the meshing portion of the flexible wheel and the steel wheel extends into the first concave cavity.

[0014] Preferably, the brake assembly includes a brake shaft and a brake cover plate, the brake shaft is fixedly connected to the motor shaft, the brake cover plate is fixedly connected to the outer shell, and the outer circle of the motor shaft is connected to the outer shell through a large bearing and a brake cover plate; the outer circle of the motor shaft on one side close to the brake assembly cooperates with the motor stator to form a second concave cavity; the inner circle of the large bearing and the brake cover plate are arranged in the second concave cavity, and the inner circle of the large bearing contacts with the outer circle of the motor shaft.

[0015] Preferably, the outer circle of the brake cover plate extends out of the second concave cavity, and the outer circle of the brake cover plate is abutted and fixed by a fixing piece fixed on the outer shell.

[0016] Preferably, the fixing member comprises a top screw, and the top screw can eliminate the bearing clearance by applying an external force before locking.

[0017] Preferably, a washer or a shaft retaining ring for limiting the axial displacement of the small bearing is disposed on the outer periphery of the hollow shaft; the washer or the shaft retaining ring is disposed on a side of the small bearing away from the brake assembly.

[0018] Preferably, the brake assembly includes a brake shaft and a brake cover plate, the brake shaft is fixedly connected to the motor shaft, the brake cover plate is fixedly connected to the housing, and the outer circle of the motor shaft is connected to the housing through a large bearing and the brake cover plate; the brake assembly also includes a brake pad, an armature and an electromagnet; the electromagnet separates the armature from the brake pad or presses the brake pad onto the brake cover plate by applying magnetic force to the armature or disconnecting the magnetic force.

[0019] Preferably, the electromagnet is ring-shaped, and an encoder circuit board is fixedly mounted on the inner circle of the electromagnet; an output end encoder is arranged on the hollow shaft, and the output end encoder is coupled to the encoder circuit board.

[0020] A joint structure provided by the present invention adopts an axially compact joint module.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. The present invention extends the meshing part of the flexible wheel and the steel wheel into the motor shaft, and overlaps the flexible wheel, the steel wheel and the motor shaft in the axial dimension, which helps to improve the axial compactness of the joint module.

[0023] 2. The double-support structure of the small bearing and the large bearing of the present invention can enhance the stability of the motor shaft rotation on the one hand, and on the other hand, the axial overlapping distribution of the two bearings can reduce the total length of the joint, which helps to improve the axial compactness of the joint module.

[0024] 3. The present invention uses the brake cover plate as a brake component on the one hand, which can brake by friction with the brake pad; on the other hand, it serves as an outer ring support of the bearing and has the function of a bearing seat. One part has multiple functions, and there is no need to design an additional bearing seat, which saves space and helps to improve the compactness of the structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0026] Figure 1 This is a schematic diagram of the overall structure of the joint module mainly embodied in the present invention;

[0027] Figure 2 This is a cross-sectional view mainly showing the overall structure of the joint module of the present invention.

[0028] As shown in the figure:

[0029] Harmonic component 1 Motor shaft 33

[0030] Cross roller bearing 11 Brake shaft 34

[0031] Steel wheel 12 Brake assembly 4

[0032] Flexwheel 13 Brake cover 41

[0033] Wave generator 14 Brake pad 42

[0034] Hollow shaft 15 Armature 43

[0035] Retaining ring 16 Electromagnet 44

[0036] Housing 21 Large bearing 51

[0037] Top screw 22 Small bearing 52

[0038] Motor assembly 3 Input encoder 61

[0039] Motor stator 31 Encoder circuit board 62

[0040] Motor rotor 32 Output encoder 63 DETAILED DESCRIPTION

[0041] The present invention is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but are not intended to limit the present invention in any form. It should be noted that, for those of ordinary skill in the art, several changes and improvements can also be made without departing from the concept of the present invention. These all belong to the protection scope of the present invention.

[0042] like Figure 1 and Figure 2 As shown, an axially compact joint module provided according to the present invention includes a housing 21, a harmonic component 1, 3 motor components and a brake component 4, and the harmonic component 1, the 3 motor components and the brake component 4 are arranged in sequence along the axial direction of the housing 21.

[0043] The harmonic component 1 includes a cross roller bearing 11, a steel wheel 12, a flexible wheel 13, a wave generator 14 and a hollow shaft 15. The outer ring of the cross roller bearing 11 is fixedly connected to the steel wheel 12, the inner ring of the cross roller bearing 11 is fixedly connected to the hollow shaft 15, the flexible wheel 13 is meshed with the steel wheel 12, and the flexible wheel 13 is connected to the wave generator 14 through a bearing. The motor component 3 includes a motor stator 31, a motor rotor 32 and a motor shaft 33. The motor stator 31 is coupled with the motor rotor 32, the motor shaft 33 is fixedly connected with the motor rotor 32, the meshing part of the flexible wheel 13 and the steel wheel 12 extends into the motor shaft 33, and a small bearing 52 is arranged between the inner circle of the motor shaft 33 and the hollow shaft 15. The brake assembly 4 includes a brake shaft 34 and a brake cover plate 41 . The brake shaft 34 is fixedly connected to the motor shaft 33 . The brake cover plate 41 is fixedly connected to the housing 21 . The outer circle of the motor shaft 33 is connected to the housing 21 through a large bearing 51 and the brake cover plate 41 .

[0044] The technical solution of the present application extends the meshing part of the flexible wheel 13 and the steel wheel 12 into the motor shaft 33 through the design of the joint module structure, and overlaps them in the axial dimension. The double-support structure of the small bearing 52 and the large bearing 51 can enhance the rotation stability of the motor shaft 33, and the axial overlapping distribution of the two bearings can reduce the total length of the joint, thereby realizing an axially compact joint module.

[0045] Specifically, the harmonic component 1 includes a cross roller bearing 11, a steel wheel 12, a flexible wheel 13, a wave generator 14, a hollow shaft 15, etc. After the outer ring of the cross roller bearing 11 is locked with the steel wheel 12 by screws, they are locked together on the housing 21 as a component. The inner ring of the cross roller bearing 11 is locked with the hollow shaft 15 by screws, and rotates with the flexible wheel 13 and provides output. The structure of the harmonic component 1 of the present application is basically the same as the structure of the harmonic component 1 in the prior art, and will not be repeated here. It should be emphasized that the wave generator 14 of the harmonic component 1 of the present application is connected to the motor shaft 33 by an interference fit, the screw parts are omitted and the concentricity between the motor shaft 33 and the wave generator 14 is ensured. The meshing part of the flexible wheel 13 and the steel wheel 12 extends into the motor shaft 33, overlaps in the axial dimension, and optimizes the axial compactness of the joint module.

[0046] More specifically, a first concave cavity is formed on the side of the motor shaft 33 close to the harmonic component 1, and the meshing portion of the flexible wheel 13 and the steel wheel 12 extends into the first concave cavity. Further, the first concave cavity is in the shape of a "pocket", and the cup of the flexible wheel 13 of the harmonic component 1 needs a certain length to ensure strength. The meshing portion of the flexible wheel 13 and the steel wheel 12 is extended into the motor shaft 33, and overlaps in the axial dimension. The outer circle of the motor shaft 33 close to the brake component 4 and the motor stator 31 cooperate to form a second concave cavity, and the inner circle of the large bearing 51 and the brake cover plate 41 are arranged in the second concave cavity, and the inner circle of the large bearing 51 contacts the outer circle of the motor shaft 33. The outer circle of the brake cover plate 41 extends out of the second concave cavity, and the outer circle of the brake cover plate 41 is fixed by abutting against a fixing member fixed on the housing 21. The fixing member includes a top screw 22, and the top screw 22 can eliminate the bearing clearance by applying an external force before locking.

[0047] The outer ring of the motor shaft 33 is attached to the motor rotor 32 with a retaining adhesive. The motor stator 31 is attached to the joint housing 21 with a retaining adhesive. The inner circle of the motor shaft 33 is supported by a small bearing 52, and the outer circle is supported by a large bearing 51. The double-support structure can enhance the stability of the rotation of the motor shaft 33, and the axial overlapping distribution of the two bearings can reduce the total length of the joint. The motor shaft 33 is connected to the brake shaft 34 with screws. The brake shaft 34 also serves as the mounting base of the input end encoder 61. The input end encoder 61 rotates with the motor shaft 33 to provide input end position, speed and other signals.

[0048] Specifically, the brake assembly 4 further includes a brake pad 42, an armature 43 and an electromagnet 44; the electromagnet 44 separates the armature 43 from the brake pad 42 or presses the brake pad 42 onto the brake cover plate 41 by applying magnetic force to the armature 43 or disconnecting the magnetic force. The electromagnet 44 is annular, and an encoder circuit board 62 is fixedly mounted on the inner circle of the electromagnet 44; an output end encoder 63 is arranged on the hollow shaft 15, and the output end encoder 63 is coupled to the encoder circuit board 62.

[0049] In a feasible implementation, the brake assembly 4 is mainly composed of a brake cover plate 41, a brake pad 42, an armature 43, and an electromagnet 44. The brake cover plate 41 also supports the outer ring of the large bearing 51. The outer ring of the brake cover plate 41 is processed with uniformly distributed platforms, which are supported and locked by the top screw 22 of the housing 21. Before locking, the bearing clearance can be eliminated by applying external force. The inner circle of the electromagnet 44 has three bosses and threaded holes, which can lock the encoder circuit board 62. The output end encoder 63 is pressed onto the hollow shaft 15 by interference fit, providing signals such as the position and speed of the output end.

[0050] In a preferred embodiment, the small bearing 52 and the large bearing 51 partially or completely overlap in the axial direction.

[0051] In a preferred embodiment, a washer or shaft retaining ring 16 for limiting the axial displacement of the small bearing 52 is disposed on the outer periphery of the hollow shaft 15 ; the washer or shaft retaining ring 16 is disposed on the side of the small bearing 52 away from the brake assembly 4 .

[0052] It should be noted that the harmonic component 1 is inserted into the motor component 3, the support bearings of the motor shaft 33 are distributed inside and outside, and the brake component 4 is fixed to the housing 21 using the top screw 22. This design arranges the parts to overlap in the axial dimension as much as possible, minimizes the axial dimension of the joint and the overall weight of the joint, and has significant advantages such as high lightness and high energy density.

[0053] The present invention also provides a joint structure, which adopts an axially compact joint module. The joint structure can be realized by executing the process steps of the axially compact joint module method.

[0054] In the description of the present application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0055] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. An axially compact joint module, characterized in that: It comprises a housing (21), a harmonic component (1), a motor component (3) and a brake component (4), wherein the harmonic component (1), the motor component (3) and the brake component (4) are arranged in sequence along the axial direction of the housing (21); The harmonic component (1) comprises a cross roller bearing (11), a steel wheel (12), a flexible wheel (13), a wave generator (14) and a hollow shaft (15), wherein the outer ring of the cross roller bearing (11) is fixedly connected to the steel wheel (12), the inner ring of the cross roller bearing (11) is fixedly connected to the hollow shaft (15), the flexible wheel (13) is meshed with the steel wheel (12), and the flexible wheel (13) is connected to the wave generator (14) via a bearing; The motor assembly (3) comprises a motor stator (31), a motor rotor (32) and a motor shaft (33); the motor stator (31) is coupled to the motor rotor (32); the motor shaft (33) is fixedly connected to the motor rotor (32); the meshing portion of the flexible wheel (13) and the steel wheel (12) extends into the motor shaft (33); and a small bearing (52) is provided between the inner circle of the motor shaft (33) and the hollow shaft (15).

2. The axially compact joint module according to claim 1, characterized in that: The small bearing (52) and the large bearing (51) partially or completely overlap in the axial direction.

3. The axially compact joint module according to claim 1, characterized in that: A first concave cavity is formed on one side of the motor shaft (33) close to the harmonic component (1), and the meshing portion between the flexible wheel (13) and the steel wheel (12) extends into the first concave cavity.

4. The axially compact joint module according to claim 1, characterized in that: The brake assembly (4) comprises a brake shaft (34) and a brake cover plate (41), wherein the brake shaft (34) is fixedly connected to the motor shaft (33), the brake cover plate (41) is fixedly connected to the housing (21), and the outer circle of the motor shaft (33) is matched with the housing (21) through a large bearing (51) and the brake cover plate (41); The outer circle of one side of the motor shaft (33) close to the brake assembly (4) cooperates with the motor stator (31) to form a second concave cavity; The inner circles of the large bearing (51) and the brake cover plate (41) are arranged in the second concave cavity, and the inner circle of the large bearing (51) is in contact with the outer circle of the motor shaft (33).

5. The axially compact joint module according to claim 4, characterized in that: The outer circle of the brake cover plate (41) extends out of the second concave cavity, and the outer circle of the brake cover plate (41) is abutted and fixed by a fixing piece fixed on the outer shell (21).

6. The axially compact joint module according to claim 5, characterized in that: The fixing member comprises a top screw (22), and the top screw (22) can eliminate the bearing clearance by applying an external force before locking.

7. The axially compact joint module according to claim 1, characterized in that: The outer periphery of the hollow shaft (15) is provided with a washer or a shaft retaining ring (16) for limiting the axial displacement of the small bearing (52); The washer or shaft retaining ring (16) is arranged on the side of the small bearing (52) away from the brake assembly (4).

8. The axially compact joint module according to claim 1, characterized in that: The brake assembly (4) comprises a brake shaft (34) and a brake cover plate (41), wherein the brake shaft (34) is fixedly connected to the motor shaft (33), the brake cover plate (41) is fixedly connected to the housing (21), and the outer circle of the motor shaft (33) is matched with the housing (21) through a large bearing (51) and the brake cover plate (41); The brake assembly (4) further comprises a brake pad (42), an armature (43) and an electromagnet (44); The electromagnet (44) separates the armature (43) from the brake pad (42) or presses the brake pad (42) onto the brake cover plate (41) by applying magnetic force to the armature (43) or disconnecting the magnetic force.

9. The axially compact joint module according to claim 8, characterized in that: The electromagnet (44) is ring-shaped, and an encoder circuit board (62) is fixedly mounted on the inner circle of the electromagnet (44); An output end encoder (63) is arranged on the hollow shaft (15), and the output end encoder (63) is coupled to an encoder circuit board (62).

10. A joint structure, characterized in that: An axially compact joint module as described in any one of claims 1 to 9 is adopted.

Images