Joint module

Abstract

The invention relates to the technical field of robots, in particular to a joint module. The joint module comprises a joint shell, a driver, a motor assembly and a speed reducer, wherein the joint shell is provided with an assembly cavity penetrating in the axial direction, the driver is arranged at the first end of the joint shell, the motor assembly and the speed reducer are arranged in the assembly cavity of the joint shell, and a fixing shaft is coaxially arranged in the assembly cavity. A stator part of the motor assembly is fixedly arranged on the periphery of the fixed shaft, and a rotor part of the motor assembly is rotatably arranged outside the stator part; the speed reducer is annularly arranged on the periphery of the fixing shaft, and the input end of the speed reducer is directly connected with the rotor part. On the basis, parts such as a power input shaft and a power output shaft of a traditional joint module are omitted, the overall length of the joint module can be reduced, the internal integration degree of the joint module is improved, and the joint module is lighter.

Description

Technical Field

[0001] The present invention relates to the field of robotics technology, and in particular to a joint module. Background Art

[0002] As the application fields of robots increase, collaborative robots, as automated labor that works in collaboration with humans, have entered more light industrial production. The movement of each degree of freedom of the collaborative robot is generated by the joint module at each joint. The joint module usually includes a joint housing, a power input shaft arranged in the joint housing and on the same axis, a power output shaft, a driver, a brake, a motor assembly, an encoder and a harmonic reducer. The driver is arranged at the first end of the joint housing, and the harmonic reducer is arranged at the second end of the joint housing. The power output shaft is passed through the joint housing along the axial direction, the power input shaft is sleeved on the outer periphery of the power output shaft, the second end of the power input shaft and the power output shaft are connected to the harmonic reducer, and the first end extends to the first end of the joint housing along the axial direction. The rotor part of the motor assembly is arranged on the outer periphery of the power input shaft to drive it to rotate, and the stator part of the motor assembly is arranged on the outer periphery of the rotor part and is connected to the joint housing.

[0003] Conventional technology requires both a power input shaft and a power output shaft, with the motor assembly's rotor fixed to the outer periphery of the power output shaft. This allows high-speed, low-torque power to be transmitted to a harmonic reducer via the power input shaft. After being decelerated by the harmonic reducer, the low-speed, high-torque power is output via the power output shaft. This not only increases the structural complexity but also the axial length of the joint module, failing to meet the requirements for lightweight and miniaturized joint modules. Summary of the Invention

[0004] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a joint module.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is: a joint module is provided, including a joint housing having an assembly cavity passing through in the axial direction, a driver arranged at the first end of the joint housing, a motor assembly and a reducer arranged in the assembly cavity, and a fixed shaft is coaxially arranged in the assembly cavity; the stator part of the motor assembly is fixedly arranged on the outer periphery of the fixed shaft, and the rotor part of the motor assembly is rotatably arranged outside the stator part; the reducer is arranged on the outer periphery of the fixed shaft and its input end is directly connected to the rotor part.

[0006] Furthermore, the reducer includes a cam arranged around the outer periphery of the rotor portion and rotating therewith, a first bearing arranged around the outer periphery of the cam, a flexible spline arranged around the outer periphery of the first bearing and rotating with the cam, and a rigid wheel assembly arranged around the outer periphery of the flexible spline, the cam serving as the input end of the reducer, which is used to drive the flexible spline to rotate, the flexible spline cooperates with the rigid wheel assembly to reduce the rotation speed, and the rigid wheel assembly is used to output the decelerated output power;

[0007] The rigid wheel assembly includes a reduction rigid wheel fixed in the joint housing and meshed with the outer periphery of the flexible wheel, and an output rigid wheel rotatably disposed in the joint housing and meshed with the flexible wheel, the reduction rigid wheel is used to cooperate with the flexible wheel to reduce the rotation speed of the flexible wheel, and the output rigid wheel is used to output the decelerated output power;

[0008] The outer periphery of the reduction rigid wheel is fixed to the inner wall surface of the joint housing, the inner periphery of the reduction rigid wheel is meshed with the outer periphery of the first end of the flexible wheel, and the number of internal teeth of the reduction rigid wheel is greater than the number of external teeth of the flexible wheel; the inner periphery of the output rigid wheel is meshed with the outer periphery of the second end of the flexible wheel, and the number of internal teeth of the output rigid wheel is adapted to the number of internal teeth of the flexible wheel, and the outer periphery of the output rigid wheel is connected to the joint housing through a second bearing.

[0009] Furthermore, the first end of the cam is connected to the fixed shaft via a third bearing, and the second end of the cam is connected to the fixed shaft via a fourth bearing;

[0010] The second end of the cam is provided with a rotor part of the encoder, which is arranged around the outer circumference of the fixed shaft and rotates with the cam; the stator part of the encoder is provided at a position on the fixed shaft corresponding to the rotor part of the encoder, and the rotor part and the stator part of the encoder are both accommodated in the inner empty space of the rigid wheel assembly.

[0011] Furthermore, the first end of the cam protrudes from the first end surface of the rotor portion; a ring portion having a diameter adapted to the inner diameter of the first end of the cam is provided on the fixed shaft at a position corresponding to the first end of the cam; the inner ring of the third bearing is connected to the ring portion, and the outer ring is connected to the first end of the cam;

[0012] The second end of the cam has a second end plate extending inward, and a through hole with an inner diameter matching the outer diameter of the fixed shaft is coaxially arranged on the second end plate. The hole wall of the through hole is connected to the outer ring of the fourth bearing, and the inner ring of the fourth bearing is fixed to the outer periphery of the fixed shaft.

[0013] Furthermore, the outer periphery of the annular portion is provided with a first stop portion for resisting the first end of the inner ring of the third bearing, and the second end of the outer ring of the third bearing is limited by the rotor part of the motor assembly; the first end of the through hole is provided with a second stop portion for resisting the outer ring of the fourth bearing, and the fixed shaft is provided with a third stop portion for stopping the second end of the inner ring of the fourth bearing, and the third stop portion is configured as a stop ring passed through the center hole of the rotor part of the encoder, and the stop ring is held between the inner ring of the fourth bearing and the stator part of the encoder.

[0014] Furthermore, the joint housing is provided with an assembly ring groove for assembling the rigid wheel assembly, which has a first groove wall close to the first end direction of the joint housing, a second groove wall close to the second end direction of the joint housing, and a groove bottom wall close to the outer wall surface of the joint housing;

[0015] The outer circumference of the reduction rigid wheel is fixedly connected to the assembly ring groove, and the first end face of the reduction rigid wheel abuts against the first groove wall of the assembly ring groove; the wall thickness of the reduction rigid wheel is less than the depth of the assembly ring groove so that the reduction rigid wheel sinks into the assembly ring groove; when the flexible wheel is engaged with the inner circumference of the reduction rigid wheel, the outer circumference of the flexible wheel is placed in the assembly ring groove, the first end of the flexible wheel is limited by the part of the first groove wall that protrudes out of the inner circumference of the reduction rigid wheel, and the second end of the flexible wheel can be limited by the output rigid wheel.

[0016] Furthermore, the inner circumference of the output rigid wheel is provided with a stop portion which is held at the second end of the flexible wheel, and the stop portion cooperates with the first groove wall of the assembly ring groove to axially limit the flexible wheel.

[0017] Furthermore, the output rigid wheel is configured to be at least partially disposed in the assembly ring groove, and the output rigid wheel includes a first section adapted to the outer diameter of the assembly ring groove, a second section adapted to the inner diameter of the assembly ring groove, and a third end plate formed at the second end of the second section; the inner circumference of the first end of the first section is engaged with the outer circumference of the flexible wheel, the inner diameter of the second end of the first section is larger than the inner diameter of the first end to form the stop portion, and an avoidance groove is formed on the outer circumference of the second end of the second section for avoiding the second bearing, the inner ring of the second bearing is fixed at the avoidance groove, and the outer ring is fixed to the inner circumference of the joint housing.

[0018] Furthermore, an embedding groove for accommodating and fixing the outer ring of the second bearing is provided on the inner wall of the joint housing. The outer ring of the second bearing is axially limited by the embedding groove, and the inner ring is axially limited by the avoidance groove.

[0019] Furthermore, the second end of the output rigid wheel is connected to an output flange, and the output flange is rotatably arranged on the second end of the joint housing and rotates with the output rigid wheel; the output flange has a ring plate and a second convex ring coaxially arranged on the first end of the ring plate, the second convex ring and the ring plate both have a center hole with the same aperture, a fifth bearing is arranged between the hole wall of the center hole and the fixed shaft, the inner ring of the fifth bearing is fixedly arranged on the outer periphery of the fixed shaft, and the outer ring is fixedly arranged on the hole wall of the center hole; a fourth stop portion for resisting the first end of the inner ring of the fifth bearing is provided on the fixed shaft, and a fifth stop portion for resisting the second end of the outer ring of the fifth bearing is provided on the hole wall of the second end of the center hole.

[0020] The joint module of the present invention has at least the following beneficial effects: (1) It adopts a design route that is opposite to the traditional joint module in which the stator part of the motor assembly is outside and the rotor part is inside. The motor assembly is configured with the stator part inside and the rotor part outside. The rotor part outside can be directly connected to the input end of the reducer, eliminating the power input shaft, power output shaft and other components of the traditional joint module, which can reduce the overall length of the joint module, improve the internal integration of the joint module, make the joint module more lightweight, and save manufacturing costs. (2) The design circuit of the traditional harmonic reducer is changed so that its input end is directly connected to the rotor part, that is, the cam of the harmonic reducer is directly fixed to the outer periphery of the rotor part, and the rigid wheel assembly is designed to include a reduction rigid wheel and an output rigid wheel meshed with the outer periphery of the flexible wheel, so that the reduction rigid wheel decelerates the flexible wheel and the output rigid wheel directly outputs the output power after deceleration; In addition, the flexible wheel is directly designed as a cylindrical flexible wheel, eliminating the need for a flexible wheel pressure plate and a flexible wheel and power output shaft connection assembly in the traditional technology, so that the output rigid wheel is directly connected to the external component through the output flange, reducing the number of parts of the reducer, further reducing the internal space occupied by the joint module, further making the joint module lightweight, and further reducing the manufacturing cost. (3) The encoder is directly designed in the inner space of the rigid wheel assembly, saving the installation space of the encoder and not occupying the axial length of the joint module. Compared with the traditional encoder design method, the axial length of the joint module can be reduced, the layout compactness of the joint module can be further improved, and the integration of the joint module can be improved. (4) By integrating the motor assembly with the reducer, high-performance engineering plastics can be used for the internal and external gears, and the injection molding process is adopted to ensure that the parts meet the strength requirements while reducing the quality, thereby improving the production efficiency of the parts. In summary, the joint module of the present invention can reduce the volume, weight, and manufacturing costs, and has a more compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0022] Figure 1 It is a structural diagram of an embodiment of a joint module of the present invention.

[0023] Figure 2 It is a structural schematic diagram of the joint housing in one embodiment of the joint module of the present invention.

[0024] Figure 3 This is a structural diagram of the joint housing in one embodiment of the joint module of the present invention, in which the driver and encoder are hidden.

[0025] The accompanying drawings in this specification are numeraled as follows:

[0026] Joint housing 100; first end plate 110; first housing 120; first protrusion 121; first recess 122; second housing 130; second recess 131; second protrusion 132; fixed shaft 140; wire hole 141; insertion portion 142; annular platform 143; first stop 143a; motor mounting portion 144; mounting ring groove 150; embedded groove 160;

[0027] Driver 200;

[0028] Motor assembly 300; stator portion 310; rotor portion 320;

[0029] Reducer 400; cam 410; cam body 411; second end plate 412; through hole 412a; second stop portion 412b; third stop portion 412c; assembly groove 413; first bearing 420; flex spline 430; rigid pulley assembly 440; reduction rigid pulley 441; output rigid pulley 442; stop portion 442a; first section 4421; second section 4422; third end plate 4423; avoidance groove 4424; second bearing 443; third bearing 451; fourth bearing 452; output flange 460; ring plate 461; second protruding ring 462; fifth bearing 463; fourth stop portion 464; fifth stop portion 465;

[0030] Encoder 500; rotor part 510; stator part 520; fixing ring 521; bottom ring 521a; first protruding ring 521b. DETAILED DESCRIPTION

[0031] To make the purpose, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments of this application and the corresponding drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0032] The following disclosure provides a variety of different embodiments or examples for implementing the different features of the present invention. Specific examples of components and arrangements will be described below to simplify the present invention. Of course, these are merely examples and are not intended to limit the present invention. For example, in the following description, forming a first component above or on a second component may include an embodiment in which the first component and the second component are in direct contact, and may also include an embodiment in which other components may be formed between the first component and the second component so that the first component and the second component are not in direct contact. In addition, the present invention may repeat reference symbols and / or characters in multiple instances. This repetition is for simplicity and clarity and does not, by itself, represent a relationship between the multiple embodiments and / or configurations.

[0033] Furthermore, spatially relative terms, such as "below," "beneath," "below," "above," and "upper," may be used herein to readily describe the relationship of one element or component to another element(s) or component(s) as illustrated in the figures. Spatially relative terms are intended to encompass various orientations of the device in use or operation in addition to the orientation depicted in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0034] In addition, the technical parts described in the present invention and the appended claims are mainly the technical parts improved by the present invention, which does not limit the object protected by the present invention to only having such technical parts. Other known necessary components (structures and / or methods) and / or non-essential components of the protected object other than the technical parts described in the present invention and the appended claims are not described in the present invention and the appended claims because they do not fall within the scope of improvement of the present invention. However, this does not mean that the object protected by the present invention does not have these known components.

[0035] See Figure 1 , Figure 1 The structural diagram of the joint module of the present invention is shown exemplarily. Figure 1In the illustrated embodiment, the joint module includes a joint housing 100, a driver 200 arranged at the first end of the joint housing 100, a motor assembly 300 and a reducer 400 arranged in the joint housing 100. The joint housing 100 can adopt a structure that is the same as or similar to the structure or function of the prior art. The joint housing 100 has an assembly cavity arranged along its axial direction. The motor assembly 300 and the reducer 400 can be completely assembled in the joint housing 100 (in the assembly cavity), or can be at least partially assembled in the joint housing 100. For example, at least a portion of the reducer 400 is assembled in the joint housing 100. Since this embodiment does not make relevant improvements to the driver 200, the driver 200 can adopt the driver 200 structure and principle of any known joint module, and can be assembled on the joint housing 100 using any known assembly method, for example, the driver 200 is assembled on the first end face of the joint housing 100.

[0036] In this embodiment, for ease of description, the end of the joint module facing the driver 200 or used to assemble the driver 200 is referred to as the first end, and the end of the joint module axially away from the first end is referred to as the second end. This includes the first and second ends of the joint housing 100, the first and second ends of the motor assembly 300, the first and second ends of the reducer 400 and its various components, and the first and second ends of the fixed shaft 140 described below.

[0037] See Figure 2 In order to facilitate the assembly of the driver 200, a first end plate 110 is provided at the first end of the joint housing 100, and the driver 200 is arranged on the first end plate 110. The first end plate 110 is formed by extending inward in a radial direction from the first end of the joint housing 100, so that the outer shape of the first end plate 110 is an annular plate structure, and the radial dimension of its center hole is smaller than the radial dimension of the assembly cavity. In addition to facilitating the assembly of the driver 200, the provision of the first end plate 110 also facilitates the assembly of the fixed shaft 140 described below, thereby improving the compactness of the joint module and further reducing the volume of the joint module. It will be understood by those skilled in the art that the assembly method of the driver 200 and the fixed shaft 140 is not limited to assembly through the first end plate 110 provided here. In different embodiments, the assembly method of the driver 200 and the fixed shaft 140 can be adaptively changed according to different needs, which also falls within the scope of protection of the joint module of the present invention.

[0038] To facilitate assembly of the reducer 400 and the motor assembly 300, the joint housing 100 can be configured to include a first housing 120 and a second housing 130 detachably mounted at the second end of the first housing 120. The first and second housings 120, 130 are coaxially arranged along the axis and can be detachably connected via a detachable connection method, such as screwing, riveting, or snapping. In this embodiment, the driver 200 is mounted at the first end wall of the first housing 120. Specifically, the first end plate 110 is mounted at the first end of the first housing 120, forming the first end wall. To facilitate assembly, positioning structures can be provided at the mating ends of the first and second housings 120, 130, to facilitate pre-assembly alignment. The positioning structures can, for example, include a concave positioning portion, a convex positioning portion, or a concave-convex positioning portion disposed at the second end of the first housing 120. The positioning structures can also include a convex positioning portion corresponding to the concave positioning portion, a concave positioning portion corresponding to the convex positioning portion, or a convex-concave positioning portion corresponding to the concave-convex positioning portion, disposed at the first end of the second housing 130. Illustratively, the second end of the first housing 120 is provided with a first protrusion 121 and a first recess 122 distributed sequentially along the radial direction from the outside to the inside. Correspondingly, the first end of the second housing 130 is provided with a second recess 131 and a second protrusion 132 distributed sequentially along the radial direction from the outside to the inside. When the first housing 120 and the second housing 130 are mated, the first protrusion 121 protrudes into the second recess 131, and the first recess 122 accommodates the second protrusion 132.

[0039] In order to facilitate the support and assembly of the motor assembly 300, the reducer 400, the encoder 500 and other components, a fixed shaft 140 distributed along its axial direction is provided in the assembly cavity in the joint housing 100. The fixed shaft 140 can be coaxially arranged in the joint housing 100 in a detachable manner, and the fixed shaft 140 has an axially through-line hole 141. The axis of the fixed shaft 140 coincides with the axis of the joint module, so that the motor assembly 300, the reducer 400, the encoder 500 and other components supported on the periphery of the fixed shaft 140 are all coaxially distributed in the joint housing 100. As a preferred embodiment or exemplary embodiment of the joint module of the present invention, the provision of the fixed shaft 140 can make the above-mentioned motor assembly 300, the reducer 400, the encoder 500 and other components all be assembled together through the fixed shaft 140, thereby improving the integration, improving the compactness of the layout of each component in the joint housing 100, improving the support and assembly strength, and reducing the volume of the joint module.

[0040] In this embodiment, the fixed shaft 140 can be disposed in the joint housing 100 in a detachable manner such as screw connection, for example, it can be detachably connected to the first end plate 110. The fixed shaft 140 can adopt a design structure as follows: the fixed shaft 140 has an insertion portion 142, an annular portion 143, and a motor assembly portion 144 distributed in sequence from the first end to the second end. The insertion portion 142 is used to be inserted into the center hole of the first end plate 110, the position and radial dimensions of the annular portion 143 are adapted to the position and radial dimensions of the cam described below, and the radial dimensions of the motor assembly portion 144 are adapted to the inner radial direction of the stator portion of the motor assembly 300. The radial dimensions of the remaining parts of the fixed shaft 140 except the motor assembly portion 144 and the annular portion 143 can be configured to be consistent. It should be understood by those skilled in the art that the structure and dimensions of the fixed shaft 140 described in this embodiment are only examples. In different embodiments, the structure, dimensions, etc. of the fixed shaft 140 can be configured according to the requirements of different embodiments.

[0041] Please continue to see Figure 1 , the motor assembly 300 includes a stator part 310 fixedly arranged in the joint housing 100 and a rotor part 320 rotatably arranged outside the stator part 310. The stator part 310 of the motor assembly 300 can be fixedly arranged in the joint housing 100 in any fixing manner. For example, the stator part 310 of the motor assembly 300 can be fixedly arranged on the periphery of the fixed shaft 140 (such as the above-mentioned motor assembly part 144). The rotor of the motor assembly 300 is directly connected to the input end of the reducer 400, so that the high-speed rotational force is directly transmitted to the reducer 400, and the output power of the low-speed and high-torque after deceleration is output through the output end of the reducer 400. In this way, the traditional power input shaft and power output shaft structure can be eliminated, the structural complexity can be reduced, and the occupied space in the joint housing 100 can be reduced, so that the overall volume and length of the joint module can be reduced.

[0042] The reducer 400 is a harmonic reducer 400. The input end of the reducer 400 is directly connected to the rotor part 320 of the motor assembly 300, and the output end of the reducer 400 is directed toward or disposed at the second end of the joint housing 100. The reducer 400 includes a cam 410 that is arranged around the outer periphery of the rotor part 320 and rotates therewith, a first bearing 420 (such as a flexible bearing) arranged around the outer periphery of the cam 410, a flexible spline 430 that is arranged around the outer periphery of the first bearing 420 and rotates with the cam 410, and a rigid wheel assembly 440 that is arranged around the outer periphery of the flexible spline 430. The cam 410 serves as the input end of the reducer 400 and is used to drive the flexible spline 430 to rotate. The flexible spline 430 cooperates with the rigid wheel assembly 440 to reduce the rotation speed, and the rigid wheel assembly 440 is used to output the decelerated output power.

[0043] The cam 410 serves as the input end of the reducer 400 and is used to receive high-speed, low-torque input power from the rotor portion 320 of the motor assembly 300. The external structure of the cam 410, the mating relationship between the cam 410 and the flexspline 430, and the power transmission principle can all adopt the same or similar existing technologies. The cam 410 is fixedly mounted on the outer periphery of the rotor portion 320 of the motor assembly 300 so as to rotate with the rotor portion 320 of the motor assembly 300. The cam 410 can be configured such that its first end is connected to the fixed shaft 140 via a third bearing 451, for example, the first end of the cam 410 is rotatably connected to the outer periphery of the annular portion 143 via the third bearing 451. The cam 410 can be configured such that its second end is connected to the fixed shaft 140 via a fourth bearing 452, for example, the second end of the cam 410 is rotatably fixed to the outer periphery of the fixed shaft 140 via the fourth bearing 452, thereby enabling rotation around the axis of the joint module under the drive of the rotor portion 320.

[0044] See Figure 3In this embodiment, the inner wall surface of the first end of the cam 410 is connected to the outer ring of the third bearing 451, and the inner ring of the third bearing 451 is fixed to the outer circumference of the ring portion 143. The second end of the outer ring of the third bearing 451 is limited by the rotor portion 320 of the motor assembly 300, and the inner ring of the third bearing 451 is limited by the first stop portion 143a provided on the ring portion 143. The cam 410 includes a cam body 411 and a second end plate 412 provided at the second end of the cam body 411. The cam body 411 is fixedly provided on the outer circumference of the rotor portion 320 of the motor assembly 300, and the cam body 411 has a protruding section that protrudes from the rotor portion 320 toward the first end. The inner wall surface of the protruding section is connected to the outer ring of the third bearing 451. The second end plate 412 is coaxially provided with a through hole 412a (center hole) whose inner diameter matches the outer diameter of the fixed shaft 140. The wall of the through hole 412a is connected to the outer ring of the fourth bearing 452, and the inner ring of the fourth bearing 452 is fixed to the outer periphery of the fixed shaft 140. In order to prevent the fourth bearing 452 from shifting toward the first end, a second stop portion 412b is provided at the first end of the through hole 412a for limiting the first end of the outer ring of the fourth bearing 452. The fixed shaft 140 is provided with a third stop portion 412c (see FIG. 1 ) for limiting the second end of the inner ring of the fourth bearing 452. Figure 1 ).

[0045] Please continue to see Figure 1 and Figure 3The second end of the cam 410 is also provided with the rotor portion 510 of the encoder 500. The rotor portion 510 of the encoder 500 is arranged around the outer circumference of the fixed shaft 140 and rotates with the cam 410. Exemplarily, the second end surface of the cam 410 (i.e., the second end surface of the second end plate 412) is provided with a mounting groove 413 for mounting the rotor portion 510 of the encoder 500. The rotor portion 510 of the encoder 500 is mounted in the mounting groove 413, and the second end protrudes from the second end surface of the cam 410. The rotor portion 510 of the encoder 500 has a center hole with an inner diameter greater than the diameter of the fixed shaft 140, so that the rotor portion 510 of the encoder 500 can rotatably surround the outer circumference of the fixed shaft 140 and rotate with the cam 410. The stator portion 520 of the encoder 500 is provided at a position on the fixed shaft 140 corresponding to the rotor portion 510 of the encoder 500. The stator portion 520 of the encoder 500 is mounted on the fixed shaft 140 via a fixing ring 521 fixed to the fixed shaft 140. The third stop portion 412c described above is configured as a stop ring that is inserted into the center hole of the rotor portion 510 of the encoder 500. The stop ring is abutted between the inner ring of the fourth bearing 452 and the stator portion 520 (i.e., the fixing ring 521) of the encoder 500. The fixing ring 521 includes a base ring 521a with a larger outer diameter and a first protruding ring 521b coaxially formed at a first end of the base ring 521a. A stepped mounting portion is formed between the outer periphery of the first protruding ring 521b and the outer periphery of the base ring 521a. The stator portion 520 of the encoder 500 is sleeved around the outer periphery of the first protruding ring 521b and mounted on the stepped mounting portion.

[0046] The first bearing 420 is configured as a cylindrical bearing and is fixedly disposed on the outer periphery of the cam 410 (i.e., the cam body 411). The flexspline 430 is fixedly disposed on the outer periphery of the first bearing 420, and the outer periphery of the flexspline 430 is configured to mesh with the inner periphery of the rigid wheel assembly 440.

[0047] The rigid wheel assembly 440 includes a reduction rigid wheel 441 fixed in the joint housing 100 and meshed with the outer periphery of the flexible wheel 430, and an output rigid wheel 442 rotatably disposed in the joint housing 100 and meshed with the flexible wheel 430. The reduction rigid wheel 441 is used to cooperate with the flexible wheel 430 to reduce the rotation speed of the flexible wheel 430, and the output rigid wheel 442 is used to output the decelerated output power.

[0048] The outer periphery of the reduction rigid pulley 441 is fixed to the inner wall of the joint housing 100. The inner periphery of the reduction rigid pulley 441 meshes with the outer periphery of the first end of the flex spline 430, and the number of internal teeth of the reduction rigid pulley 441 is greater than the number of external teeth of the flex spline 430. The inner periphery of the first end of the output rigid pulley 442 meshes with the outer periphery of the second end of the flex spline 430, and the number of internal teeth of the output rigid pulley 442 matches the number of internal teeth of the flex spline 430. The outer periphery of the output rigid pulley 442 is connected to the joint housing 100 via a second bearing 443.

[0049] Please continue to see Figure 2 In order to facilitate the assembly of the flexible wheel 430 and the rigid wheel assembly 440, reduce space occupancy, and improve the compactness of the layout, an assembly ring groove 150 is provided in the joint housing 100. The assembly ring groove 150 is formed outward from the inner wall surface of the joint housing 100, and has a first groove wall 151 close to the first end of the joint housing 100, a second groove wall 152 close to the second end of the joint housing 100, and a groove bottom wall 153 close to the outer wall surface of the joint housing 100. The assembly ring groove 150 is divided into two parts in the axial direction by the first housing 120 and the second housing 130, that is, the first half of the assembly ring groove 150 in the axial direction is opened at the second end of the first housing 120, and the second half of the assembly ring groove 150 in the axial direction is opened at the first end of the second housing 130. When they are aligned, the assembly ring groove 150 is formed.

[0050] The outer circumference of the reduction rigid pulley 441 is fixedly connected to the bottom wall 153 of the assembly ring groove 150 (the first half groove), and the first end surface of the reduction rigid pulley 441 abuts the first groove wall 151 of the assembly ring groove 150. In this embodiment, the wall thickness of the reduction rigid pulley 441 is less than the depth of the assembly ring groove 150, allowing the reduction rigid pulley 441 to sink into the assembly ring groove 150 and the first groove wall 151 to protrude inwardly beyond the inner circumference of the reduction rigid pulley 441. With this arrangement, when the flex spline 430 engages with the inner circumference of the reduction rigid pulley 441, the outer circumference of the flex spline 430 rests within the assembly ring groove 150. The first end of the flex spline 430 is restrained by the portion of the first groove wall 151 protruding beyond the inner circumference of the reduction rigid pulley 441, while the second end of the flex spline 430 is restrained by the output rigid pulley 442.

[0051] The inner circumference of the output rigid pulley 442 is provided with a stopper 442a that blocks the second end of the flexspline 430. The stopper 442a cooperates with the first groove wall 151 of the assembly ring groove 150 to axially limit the flexspline 430. The inner diameter of the output rigid pulley 442 is larger than the outer diameter of the encoder 500 to accommodate the encoder 500, thereby improving the tightness between them, increasing the compactness of the layout, and reducing the axial length of the joint module.

[0052] A gap is formed between the output rigid pulley 442 and the inner wall surface of the joint housing 100 to facilitate rotation of the output rigid pulley 442. The output rigid pulley 442 can be configured to be at least partially disposed within the assembly ring groove 150. For example, the output rigid pulley 442 can include a first section 4421 adapted to the outer diameter of the assembly ring groove 150, a second section 4422 adapted to the inner diameter (the diameter of the notch surface) of the assembly ring groove 150, and a third end plate 4423 formed at the second end of the second section 4422. The third end plate 4423 is located outside the second end of the encoder 500 and is similarly configured as an annular plate structure with a center hole disposed outside the fixed shaft 140. The outer diameter of the first section 4421 is smaller than the outer diameter of the assembly ring groove 150, forming a first gap between the first section 4421 and the groove bottom wall 153. The inner circumference of the first end of the first section 4421 engages with the outer circumference of the flexible spline 430. The inner diameter of the second end of the first section 4421 is larger than the inner diameter of the first end, forming the stopper 442a. The outer diameter of the second section 4422 is smaller than the inner diameter of the portion of the joint housing 100 corresponding to the second section 4422, forming a second gap. A clearance groove 4424 is formed on the outer circumference of the second end of the second section 4422 to allow for the second bearing 443 to pass through. The inner ring of the second bearing 443 is fixed to the clearance groove 4424 to be axially limited by the clearance groove 4424, and the outer ring is fixed to the inner circumference of the joint housing 100 (second housing 130). In this embodiment, an inner wall of the joint housing 100 is provided with an embedding groove 160 for accommodating and fixing the outer ring of the second bearing 443 , and the outer ring of the second bearing 443 is partially embedded in the embedding groove 160 .

[0053] The output end of the reducer 400 is connected to an output flange 460. This output flange 460 is rotatably mounted on the second end of the joint housing 100 and rotates with the output rigid pulley 442, thereby transmitting the output power to an external component. In this embodiment, the output flange 460 is connected to the second end of the output rigid pulley 442, for example, to the third end plate 4423. The output flange 460 is an annular plate-like structure comprising a ring plate 461 and a second protruding ring 462 coaxially mounted on the first end of the ring plate 461. Both the second protruding ring 462 and the ring plate 461 have a central hole of the same diameter. A fifth bearing 463 is disposed between the wall of the central hole and the fixed shaft 140. The inner ring of the fifth bearing 463 is fixedly mounted on the outer circumference of the fixed shaft 140, while the outer ring is fixedly mounted on the wall of the central hole. In order to prevent the fifth bearing 463 from shifting in the axial direction, a fourth stop portion 464 (see FIG. 1 ) is provided on the fixed shaft 140 for abutting against the first end of the inner ring of the fifth bearing 463. Figure 1 ), the fourth stop portion 464 can be configured as a stop ring, the first end of which abuts against the fixing ring 521 of the encoder 500, and the second end of which abuts against the inner ring of the fifth bearing 463. The outer ring of the fifth bearing 463 is limited by providing a fifth stop portion 465 on the hole wall at the second end of the center hole. The fifth stop portion 465 can be configured as a stop ring protruding inward from the hole wall of the center hole.

[0054] Based on the above embodiments, the joint module of the present invention has at least the following beneficial effects: (1) It adopts a design route opposite to the traditional joint module in which the stator part 310 of the motor assembly 300 is outside and the rotor part 320 is inside, and the motor assembly 300 is configured with the stator part 310 inside and the rotor part 320 outside. The rotor part 320 outside can be directly connected to the input end of the reducer 400, eliminating the power input shaft, power output shaft and other components of the traditional joint module, which can reduce the overall length of the joint module, improve the internal integration of the joint module, make the joint module more lightweight, and save manufacturing costs. (2) The design circuit of the traditional harmonic reducer 400 is changed so that its input end is directly connected to the rotor part 320, that is, the cam 410 of the harmonic reducer 400 is directly fixed to the outer periphery of the rotor part 320, and the rigid wheel assembly 440 is designed to include two parts: a reduction rigid wheel 441 and an output rigid wheel 442 engaged with the outer periphery of the flexible wheel 430, so that the reduction rigid wheel 441 decelerates the flexible wheel 430, and the output rigid wheel 442 directly outputs the decelerated output power; in addition, the flexible wheel 430 is directly designed as a cylindrical flexible wheel 430, eliminating the need for the flexible wheel 430 pressure plate and the flexible wheel 430 to be configured with a connecting assembly between the flexible wheel 430 and the power output shaft in the traditional technology, so that the output rigid wheel 442 is directly connected to the external component through the output flange 460, thereby reducing the parts of the reducer 400, further reducing the internal space occupied by the joint module, further making the joint module lightweight, and further reducing the manufacturing cost. (3) The encoder 500 is directly designed in the inner space of the rigid wheel assembly 440 (output rigid wheel 442), which saves the installation space of the encoder 500 and does not occupy the axial length of the joint module. Compared with the traditional encoder 500 design method, the axial length of the joint module can be reduced, the layout compactness of the joint module can be further improved, and the integration of the joint module can be improved. (4) By integrating the motor assembly 300 with the reducer 400 part, the internal and external gears (flexible wheel and rigid wheel) can use high-performance engineering plastics and adopt injection molding technology to make the parts meet the strength and reduce the quality while improving the production efficiency of the parts. In summary, the joint module of the present invention can reduce the volume, reduce the weight, reduce the manufacturing cost, and have a more compact structure.

[0055] The above embodiments merely represent preferred embodiments of the present invention. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent for this invention shall be determined by the appended claims.

Claims

1. A joint module, comprising a joint housing having an assembly cavity extending therethrough in an axial direction, a driver disposed at a first end of the joint housing, a motor assembly disposed in the assembly cavity, and a reducer, characterized in that: A fixed shaft is coaxially arranged in the assembly cavity; the stator part of the motor assembly is fixedly arranged on the outer periphery of the fixed shaft, and the rotor part of the motor assembly is rotatably arranged outside the stator part; the reducer is arranged around the outer periphery of the fixed shaft and its input end is directly connected to the rotor part.

2. The joint module according to claim 1, wherein: The reducer includes a cam arranged around the outer periphery of the rotor portion and rotating therewith, a first bearing arranged around the outer periphery of the cam, a flexible spline arranged around the outer periphery of the first bearing and rotating with the cam, and a rigid wheel assembly arranged around the outer periphery of the flexible spline. The cam serves as the input end of the reducer and is used to drive the flexible spline to rotate. The flexible spline cooperates with the rigid wheel assembly to reduce the rotation speed. The rigid wheel assembly is used to output the decelerated output power. The rigid wheel assembly includes a reduction rigid wheel fixed in the joint housing and meshed with the outer periphery of the flexible wheel, and an output rigid wheel rotatably disposed in the joint housing and meshed with the flexible wheel, the reduction rigid wheel is used to cooperate with the flexible wheel to reduce the rotation speed of the flexible wheel, and the output rigid wheel is used to output the decelerated output power; The outer periphery of the reduction rigid wheel is fixed to the inner wall surface of the joint housing, the inner periphery of the reduction rigid wheel is meshed with the outer periphery of the first end of the flexible wheel, and the number of internal teeth of the reduction rigid wheel is greater than the number of external teeth of the flexible wheel; the inner periphery of the output rigid wheel is meshed with the outer periphery of the second end of the flexible wheel, and the number of internal teeth of the output rigid wheel is adapted to the number of internal teeth of the flexible wheel, and the outer periphery of the output rigid wheel is connected to the joint housing through a second bearing.

3. The joint module according to claim 2, wherein: The first end of the cam is connected to the fixed shaft through a third bearing, and the second end of the cam is connected to the fixed shaft through a fourth bearing; The second end of the cam is provided with a rotor part of the encoder, which is arranged around the outer circumference of the fixed shaft and rotates with the cam; the stator part of the encoder is provided at a position on the fixed shaft corresponding to the rotor part of the encoder, and the rotor part and the stator part of the encoder are both accommodated in the inner empty space of the rigid wheel assembly.

4. The joint module according to claim 3, wherein: The first end of the cam protrudes from the first end surface of the rotor portion; a ring portion having a diameter adapted to the inner diameter of the first end of the cam is provided on the fixed shaft at a position corresponding to the first end of the cam; the inner ring of the third bearing is connected to the ring portion, and the outer ring is connected to the first end of the cam; The second end of the cam has a second end plate extending inward, and a through hole with an inner diameter matching the outer diameter of the fixed shaft is coaxially arranged on the second end plate. The hole wall of the through hole is connected to the outer ring of the fourth bearing, and the inner ring of the fourth bearing is fixed to the outer periphery of the fixed shaft.

5. The joint module according to claim 4, wherein: The outer periphery of the annular portion is provided with a first stop portion for resisting the first end of the inner ring of the third bearing, and the second end of the outer ring of the third bearing is limited by the rotor part of the motor assembly; the first end of the through hole is provided with a second stop portion for resisting the outer ring of the fourth bearing, and the fixed shaft is provided with a third stop portion for stopping the second end of the inner ring of the fourth bearing, and the third stop portion is configured as a stop ring passed through the center hole of the rotor part of the encoder, and the stop ring is held between the inner ring of the fourth bearing and the stator part of the encoder.

6. The joint module according to claim 2, wherein: The joint housing is provided with an assembly ring groove for assembling the rigid wheel assembly, which has a first groove wall close to the first end direction of the joint housing, a second groove wall close to the second end direction of the joint housing, and a groove bottom wall close to the outer wall surface of the joint housing; The outer circumference of the reduction rigid wheel is fixedly connected to the assembly ring groove, and the first end face of the reduction rigid wheel abuts against the first groove wall of the assembly ring groove; the wall thickness of the reduction rigid wheel is less than the depth of the assembly ring groove so that the reduction rigid wheel sinks into the assembly ring groove; when the flexible wheel is engaged with the inner circumference of the reduction rigid wheel, the outer circumference of the flexible wheel is placed in the assembly ring groove, the first end of the flexible wheel is limited by the part of the first groove wall that protrudes out of the inner circumference of the reduction rigid wheel, and the second end of the flexible wheel can be limited by the output rigid wheel.

7. The joint module according to claim 6, wherein: The inner circumference of the output rigid wheel is provided with a stop portion which is held at the second end of the flexible wheel. The stop portion cooperates with the first groove wall of the assembly ring groove to axially limit the flexible wheel.

8. The joint module according to claim 7, wherein: The output rigid wheel is configured to be at least partially disposed in the assembly ring groove, and the output rigid wheel includes a first section adapted to the outer diameter of the assembly ring groove, a second section adapted to the inner diameter of the assembly ring groove, and a third end plate formed at the second end of the second section; the inner circumference of the first end of the first section is engaged with the outer circumference of the flexible wheel, the inner diameter of the second end of the first section is larger than the inner diameter of the first end to form the stopper, and an avoidance groove is formed on the outer circumference of the second end of the second section for avoiding the second bearing, the inner ring of the second bearing is fixed at the avoidance groove, and the outer ring is fixed to the inner circumference of the joint housing.

9. The joint module according to claim 8, wherein: An embedding groove for accommodating and fixing the outer ring of the second bearing is provided on the inner wall of the joint housing. The outer ring of the second bearing is axially limited by the embedding groove, and the inner ring is axially limited by the avoidance groove.

10. The joint module according to claim 2, wherein: The second end of the output rigid wheel is connected to an output flange, which is rotatably arranged on the second end of the joint housing and rotates with the output rigid wheel; the output flange has a ring plate and a second convex ring coaxially arranged on the first end of the ring plate, the second convex ring and the ring plate both have a center hole with the same aperture, a fifth bearing is arranged between the hole wall of the center hole and the fixed shaft, the inner ring of the fifth bearing is fixedly arranged on the outer periphery of the fixed shaft, and the outer ring is fixedly arranged on the hole wall of the center hole; the fixed shaft is provided with a fourth stop portion for resisting the first end of the inner ring of the fifth bearing, and the hole wall of the second end of the center hole is provided with a fifth stop portion for resisting the second end of the outer ring of the fifth bearing.

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