Robot joint module

Abstract

The utility model provides a robot joint module in the technical field of robot manufacturing. The robot joint module comprises a motor assembly, a harmonic speed reducer assembly and an encoder assembly. The double-rigid-wheel harmonic speed reducer and the outer rotor motor are adopted, the motor is embedded into a flexible wheel of the harmonic speed reducer, the axial length of the joint module is effectively shortened, and the radial size is reduced; the motor rotor is elliptical and is in contact with the inner ring of the flexible bearing, and the outer ring of the flexible bearing is in contact with the inner ring of the flexible gear of the harmonic speed reducer, so that the motor rotor shell and the flexible bearing jointly serve as a harmonic generator, and meanwhile, the motor stator shell and the harmonic speed reducer shell are integrally designed, so that the number of parts is reduced; the rotor end cover, the rotor rotating shaft, the output flange and the output shaft are all integrally designed into hollow shafts, and the output hollow shaft of the output flange is arranged in the rotor hollow shaft, so that cables can be arranged in the module. The integrated design of motor parts and harmonic reducer parts has the cost advantage in the aspects of manufacturing and maintenance.

Description

A robot joint module Technical Field

[0001] This utility model relates to the field of robot manufacturing technology, and in particular to a robot joint module. Background Technology

[0002] With rising labor costs and rapid technological advancements, robotics has been widely adopted in factories and service industries. Joint modules, as core components of robots, play a crucial role in enhancing their motion performance.

[0003] Currently, the design trend for robot joint modules is towards miniaturization, while simultaneously addressing wiring issues to optimize robot control. Traditional robots typically employ external wiring, which is not only cluttered but can also pose safety risks. Therefore, there is a pressing need in the market for more compact joint modules. With the increasing number of robot applications in production lines and everyday life, especially robots that need to collaborate or move with humans, there are stringent requirements regarding the size and weight of joint modules. Therefore, reducing the volume and weight of joint modules has become particularly important. Traditional robot joint modules are increasingly unable to meet these miniaturization application demands.

[0004] However, existing robot joint modules typically use planetary gearboxes as the core component, integrating motors, encoders, and other parts. This design stacks the main components axially, resulting in a long axial length of the module. Furthermore, due to the large radial dimension of the planetary gearbox, the overall module size is correspondingly large. Moreover, the cables for planetary geared joint modules need to be routed externally, which not only occupies more space but also poses safety hazards.

[0005] Alternatively, a top-hat type harmonic reducer (also known as a hat-shaped harmonic reducer) is used as the basis, with its flexible wheel shaped like a top hat. In this design, the input and output shafts are connected to the harmonic reducer, while the motor, brake, encoder, and drive plate are mounted axially on the input and output shafts. The input and output shafts are typically designed as coaxial hollow cylindrical shafts, with the hollow portion used for wiring. The input shaft is located outside the output shaft, and the output shaft is longer than the input shaft to accommodate the encoder, providing feedback on the speeds of the input and output shafts. However, the internal space of the harmonic reducer is not fully utilized beyond the space passing through the input and output shafts. The axial connection of other components to the harmonic reducer results in a relatively long axial length of the joint module, failing to effectively reduce the overall volume of the module. Summary of the Invention

[0006] This invention provides a robot joint module with lower cost and higher integration compared to existing robot joint modules. It employs a dual-rigid-wheel harmonic reducer and an external rotor motor. The elliptical design of the motor rotor housing allows the rotor housing and flexible bearings to jointly act as a harmonic generator. The rotor end cover, rotor shaft, output flange, and output shaft are all integrated into a hollow shaft design, with the output flange's hollow shaft being housed within the rotor's hollow shaft. The integrated design of the motor and harmonic reducer components in this invention provides cost advantages in manufacturing and maintenance.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: a robot joint module, comprising three parts: a motor assembly, a harmonic reducer assembly, and an encoder assembly.

[0008] The motor assembly is a standalone module consisting of a flange base, stator core, windings, second bearing, third bearing, magnets, rotor housing, rotor end cover, second oil seal, and shaft retaining ring. The upper and lower end faces of the second oil seal respectively fit against the inner end face of the flange base and the end face of the rotor housing. The outer ring of the rotor housing is elliptical. The flange base has a cable outlet hole for cable passage and connection to an external drive PCBA.

[0009] A harmonic reducer assembly includes: a stationary rigid wheel, an output rigid wheel, a first bearing, a flexible wheel, a flexible bearing, a first screw, and an output flange. The inner side of the rollers of the flexible bearing is interference-fitted with the elliptical outer ring of the rotor housing, and the outer side of the rollers contacts the inner ring of the flexible wheel. A certain number of teeth are evenly distributed on the outer ring of the flexible wheel, engaging with the same number of teeth on the inner ring of the stationary rigid wheel. The outer ring of the stationary rigid wheel is interference-fitted with and fixedly connected to the inner ring of the flange base. The first bearing is installed in the flange base, and its outer ring is fixedly connected to the inner ring of the flange base. The output rigid wheel and the output flange are fixedly connected by the first screw, and the outer ring of the output rigid wheel is coaxially fitted with the inner ring of the output flange. The output rigid wheel and the output flange are placed in the flange base, and the end face of the output flange is in contact with the end face of the first bearing. The inner ring of the first bearing engages with and is fixedly connected to the outer ring of the output rigid wheel.

[0010] The encoder assembly, comprising a fourth bearing, encoder main gear, encoder cover plate, encoder magnet, second screw, fifth bearing, encoder secondary gear, encoder housing, magnetic induction chip, PCBA, and third screw, is a separate module. The encoder secondary gear has the same number of teeth as the encoder main gear and meshes with it for drive. A high-performance two-pole encoder magnet is embedded within the inner hole of the encoder secondary gear; this magnet rotates with the encoder secondary gear, carrying the speed and position information of the motor rotor. The magnetic induction chip is soldered onto the PCBA.

[0011] The motor rotor end cover is provided with a hollow shaft, the output flange is provided with an output flange hollow shaft, the encoder main gear is provided with a hollow hole, and the output flange hollow shaft passes through the hollow shaft of the motor rotor end cover and the hollow hole of the encoder main gear.

[0012] The stop of the encoder main gear and the stop of the hollow shaft of the motor assembly rotor end cover are a concave-convex fit structure.

[0013] The hollow shaft of the output flange is provided with a first oil seal, the inner ring of which is interference-fitted with the outer ring of the hollow shaft of the output flange; the upper and lower end faces of the first oil seal are respectively in contact with the outer end face of the rotor end cover and the inner end face of the output flange.

[0014] The entire encoder assembly is fixed to the flange base by a third screw, and the inner ring of the encoder housing and the outer ring of the flange base are coaxially fitted; the inner end face of the encoder housing is in contact with the end face of the flange base.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) The double rigid wheel harmonic reducer and the external rotor motor embed the motor inside the flexible wheel of the harmonic reducer, which effectively shortens the axial length of the joint module and reduces the radial dimension;

[0017] (2) The motor rotor is designed in an elliptical shape, contacting the inner ring of the flexible bearing, while the outer ring of the flexible bearing contacts the inner ring of the flex wheel of the harmonic reducer. This allows the motor rotor housing and the flexible bearing to act as a harmonic generator. When the motor rotor rotates, the rollers of the flexible bearing undergo periodic radial deformation, which in turn causes the flex wheel to undergo periodic deformation, driving the rigid wheel, which has a different number of teeth than the flex wheel, to rotate. The output rigid wheel is connected to the output flange by screws, thereby achieving the output of torque and speed.

[0018] (3) The motor stator housing and the harmonic reducer housing are designed as a single unit, which reduces the number of parts, simplifies the assembly process, and reduces the module size;

[0019] (4) The rotor end cover and rotor shaft are integrated into a hollow shaft, and the output flange and output shaft are also integrated into a hollow shaft. The output hollow shaft of the output flange is built into the hollow shaft of the rotor. This design allows cables to be arranged inside the module, which facilitates the cable routing between the joint module and other modules of the robot, and improves the overall space utilization and aesthetics.

[0020] In summary, this utility model's robot joint module reduces the number of parts, simplifies the assembly process, and lowers the complexity and cost of the device, while also reducing the equipment's failure rate and improving its reliability. Secondly, the robot joint module's motor and harmonic reducer components are all integrated into a single unit, giving it cost advantages in manufacturing and maintenance. The compact structure and hollow shaft design not only simplify the number of parts and optimize the device structure but also improve overall space utilization and aesthetics. Therefore, this utility model has broad market demand, especially in scenarios with complex functions, high space requirements, and strong aesthetic appeal, such as home service robots and market service robots, where it has enormous application potential. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention.

[0022] Figure 1 is a cross-sectional view of a robot joint module according to the present invention;

[0023] Figure 2 is a view of the motor assembly of a robot joint module according to this utility model;

[0024] Figure 3 is a view of a flexible bearing assembly for a robot joint module according to this utility model.

[0025] Figure 4 is a static rigid wheel view of a robot joint module according to this utility model;

[0026] Figure 5 is a view of the output rigid wheel of a robot joint module according to this utility model;

[0027] Figure 6 is a view of the flexible wheel of a robot joint module according to this utility model;

[0028] Figure 7 is a view of the output flange of a robot joint module according to this utility model;

[0029] Figure 8 is a view of the motor oil seal of a robot joint module according to this utility model;

[0030] Figure 9 is a view of the output oil seal of a robot joint module according to this utility model;

[0031] Figure 10 is a view of the encoder main gear of a robot joint module according to the present invention;

[0032] Figure 11 is a view of the encoder sub-gear of a robot joint module according to the present invention;

[0033] Figure 12 is a view of the encoder assembly of a robot joint module according to the present invention;

[0034] Figure 13 is a view of the rotor shell of a robot joint module according to this utility model.

[0035] The above figures include the following reference numerals:

[0036] 1. Flange base; 2. Stationary rigid wheel; 3. Output rigid wheel; 4. First bearing; 5. Flexible wheel; 6. Flexible bearing; 7. First screw; 8. Output flange; 9. Rotor end cover; 10. Second bearing; 11. First oil seal; 12. Stator core; 13. Winding; 14. Magnet; 15. Rotor housing; 16. Second oil seal; 17. Third bearing; 18. Shaft retaining ring; 19. Fourth bearing; 21. Encoder main gear; 22. Encoder cover plate; 23. Encoder magnet; 24. Second screw; 25. Fifth bearing; 26. Encoder auxiliary gear; 27. Encoder housing; 28. Magnetic induction chip; 29. ​​PCBA; 30. Third screw;

[0037] 101. First end face of flange base; 103. First inner ring of flange base; 104. Second end face of flange base; 105. Second inner ring of flange base; 108. Outer ring of flange base stop; 109. End face of flange base stop; 110. Cable outlet hole of flange base; 201. Outer ring of stationary rigid wheel; 202. Inner ring teeth of stationary rigid wheel; 301. Outer ring of output rigid wheel; 501. Inner ring of flexible wheel; 503. Outer ring teeth of flexible wheel; 602. Flexible bearing roller; 6021. Outer side of flexible bearing roller; 6022. Inner side of flexible bearing roller; 804. Output 805. Flange inner end face; 806. Output flange hollow shaft; 807. Output flange inner ring; 808. Output flange end face; 909. Rotor end cover outer end face; 9000. Motor rotor end cover hollow shaft; 901. Rotor end cover hollow shaft stop; 1101. Oil seal inner ring; 1501. Rotor housing outer ring; 1502. Rotor housing end face; 2101. Encoder main gear stop; 2102. Encoder main gear hollow hole; 2602. Encoder secondary gear inner hole; 2701. Encoder housing stop inner ring; 2702. Encoder housing stop inner end face. Detailed Implementation

[0038] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments, and the embodiments and features in the embodiments of this application can be combined with each other without conflict. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0039] It should be noted that, unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. The terms “set,” “connected,” “linked,” “through,” and “through” as used in this specification and claims should be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; as a direct connection or an indirect connection via an intermediate medium; or as a connection within two elements. When the terms “comprising” and / or “including” are used in this specification and claims, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. This utility model relates to directional descriptions, such as up, down, front, back, left, right, horizontal, vertical, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. These are merely for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of this application described herein can be implemented, for example, in a sequence other than those illustrated or described herein.

[0040] As shown in Figures 1 to 13, a robot joint module includes: a motor assembly, a harmonic reducer assembly, and an encoder assembly.

[0041] The motor assembly is an independent module, including: a flange base 1, a stator core 12, windings 13, a second bearing 10, a third bearing 17, a magnet 14, a rotor housing 15, a rotor end cover 9, a second oil seal 16, and a shaft retaining ring 18. The upper and lower end faces of the second oil seal 16 respectively abut against the first end face 101 of the flange base and the end face 1502 of the rotor housing 15, achieving a sealing effect to prevent the lubricating grease from the harmonic reducer from penetrating into the motor, thus avoiding motor malfunction. The outer ring 1501 of the rotor housing 15 is elliptical; the flange base 1 has a cable outlet hole 110 for cables to pass through and connect to an external drive PCBA.

[0042] The harmonic reducer assembly includes a stationary rigid wheel 2, an output rigid wheel 3, a first bearing 4, a flexible wheel 5, a flexible bearing 6, a first screw 7, and an output flange 8. The inner side 6022 of the flexible bearing roller 602 is interference-fitted with the elliptical outer ring 1501 of the rotor housing 15, while the outer side 6021 of the flexible bearing roller 602 contacts the inner ring 501 of the flexible wheel 5. A certain number of teeth 503 are evenly distributed on the outer ring of the flexible wheel 5, engaging with the same number of teeth 202 on the inner ring of the stationary rigid wheel 2. Because the flexible wheel 5 and the stationary rigid wheel 2 have the same number of teeth, the stationary rigid wheel 2 will not rotate relative to the flexible wheel 5 during radial periodic deformation. The outer ring 201 of the stationary rigid wheel 2 is interference-fitted and fixedly connected to the first inner ring 103 of the flange base, for example, by means of a pin, to prevent the stationary rigid wheel 2 from radially moving under force. The first bearing 4 is installed in the flange base 1, and its outer ring is fixedly connected to the second inner ring 105 of the flange base, for example, by using strong adhesive to ensure that the end face of the first bearing 4 is in contact with the second end face 104 of the flange base, preventing the first bearing 4 from radially and axially moving. The output rigid wheel 3 is connected and fixed to the output flange 8 by the first screw 7, and the outer ring 301 of the output rigid wheel 3 is precisely fitted with the inner ring 806 of the output flange 8 to ensure coaxiality. The output rigid wheel 3 and the output flange 8 are placed in the flange base 1, which contains the first bearing 4, the flexible wheel 5, the flexible bearing 6, and the motor assembly. The end face 807 of the output flange 8 is fitted with the end face of the first bearing 4 to achieve axial positioning. The inner ring of the first bearing 4 is fitted and fixedly connected to the outer ring 301 of the output rigid wheel 3, for example, by using strong adhesive to prevent radial and axial movement of the output rigid wheel 3 and the output flange 8. This design allows the motor rotor housing 15 and the flexible bearing 6 to work together as a harmonic generator. When the motor rotor rotates, the elliptical outer ring 1501 of the rotor housing 15 forces the flexible bearing 6 to undergo periodic radial deformation, which in turn drives the flexible wheel 5 to undergo periodic deformation. The stationary rigid wheel 2, which has the same number of teeth as the flexible wheel 5, does not rotate relative to it. The output rigid wheel 3, which has two more teeth than the flexible wheel 5, only rotates and moves two teeth in the circumferential direction during the radial deformation of the flexible wheel 5, thus achieving the output of torque and speed.

[0043] The encoder assembly includes: a fourth bearing 19, an encoder main gear 21, an encoder cover plate 22, an encoder magnet 23, a second screw 24, a fifth bearing 25, an encoder secondary gear 26, an encoder housing 27, a magnetic induction chip 28, a PCBA 29, and a third screw 30. The encoder secondary gear 26 has the same number of teeth as the encoder main gear 21 and meshes with it for mutual drive. Therefore, the rotational speed of the encoder secondary gear 26 is the same as that of the encoder main gear 21, i.e., the same as the rotational speed of the motor rotor. A high-performance two-pole encoder magnet 23 is embedded in the inner hole 2602 of the encoder secondary gear 26. The magnet 23 rotates with the encoder secondary gear 26, carrying the speed and position information of the motor rotor. The magnetic induction chip 28 is soldered onto the PCBA 29. By acquiring the N / S pole position and change rate of the encoder magnet 23, it obtains the rotational speed and position information of the motor rotor and transmits this information as a feedback signal to the drive controller to control the motor speed and torque.

[0044] Furthermore, the motor rotor end cover 9 is provided with a hollow shaft 903, the output flange 8 is provided with an output flange hollow shaft 805, and the encoder main gear 21 is provided with a hollow hole 2102. The output flange hollow shaft 805 passes through the hollow shaft 903 of the motor rotor end cover 9 and the hollow hole 2102 of the encoder main gear 21. This design allows for the arrangement of cables inside the module, facilitating cable routing between the joint module and other modules of the robot, and improving the overall space utilization and aesthetics.

[0045] Furthermore, the stop 2101 of the encoder main gear 21 and the hollow shaft stop 904 of the motor assembly rotor end cover 9 have a concave-convex fit structure, so that the drive encoder main gear 21 rotates at the same speed when the motor rotates.

[0046] Furthermore, the first oil seal 11 is provided on the hollow shaft 805 of the output flange, and its inner ring 1101 is interference-fitted with the outer ring of the hollow shaft 805 of the output flange. The upper and lower end faces of the first oil seal 11 are respectively in contact with the outer end face 902 of the rotor end cover 9 and the inner end face 804 of the output flange 8 to achieve a sealing effect and prevent the lubricating grease of the harmonic reducer from entering the hollow shaft 903 of the motor rotor end cover 9 and flowing out to the outside of the joint module.

[0047] In some embodiments of this utility model, the entire encoder assembly can be fixed to the flange base 1 by the third screw 30. The inner ring 2701 of the encoder housing 27 and the outer ring 108 of the flange base 1 cooperate with each other to ensure the coaxiality of the encoder main gear 21 and the motor assembly, so as to achieve smooth rotation and accurate transmission of motor rotor position and speed information. The inner end face 2702 of the encoder housing 27 fits against the end face 109 of the flange base 1, which plays a role in axial positioning and limiting, facilitating quick installation of the encoder assembly.

[0048] This document uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. Furthermore, for those skilled in the art, based on the ideas of this utility model, there will be changes in the specific implementation methods and application scope. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. A robot joint module, characterized in that, include: The system comprises a motor assembly, a harmonic reducer assembly, and an encoder assembly. The motor assembly includes: a flange base, a stator core, windings, a second bearing, a third bearing, magnets, a rotor housing, a rotor end cover, a second oil seal, and a shaft retaining ring. The upper and lower end faces of the second oil seal are respectively fitted to the inner end face of the flange base and the end face of the rotor housing. The outer ring of the rotor housing is elliptical. The flange base has a cable outlet hole for cable passage and connection to an external drive PCBA. The harmonic reducer assembly includes: a stationary rigid wheel, an output rigid wheel, a first bearing, a flexible wheel, a flexible bearing, a first screw, and an output flange. The inner side of the rollers of the flexible bearing is interference-fitted with the elliptical outer ring of the rotor housing, and the outer side of the rollers contacts the inner ring of the flexible wheel. The flexible wheel has a certain number of teeth evenly distributed on its outer ring, which mesh with the same number of teeth on the inner ring of the stationary rigid wheel; the outer ring of the stationary rigid wheel is interference-fitted with and fixedly connected to the inner ring of the flange base; the first bearing is installed in the flange base, and its outer ring is fixedly connected to the inner ring of the flange base; the output rigid wheel is fixedly connected to the output flange by a first screw, and the outer ring of the output rigid wheel is coaxially fitted with the inner ring of the first bearing; the output rigid wheel and the output flange are placed in the flange base, and the end face of the output flange is in contact with the end face of the first bearing; the encoder assembly includes a fourth bearing, an encoder main gear, an encoder cover plate, an encoder magnet, a second screw, a bearing, an encoder secondary gear, an encoder housing, a magnetic induction chip, a PCBA, and a third screw; the encoder secondary gear has the same number of teeth as the encoder main gear and meshes with it for mutual drive; a high-performance two-pole encoder magnet is built into the inner hole of the encoder secondary gear, and the encoder magnet rotates with the encoder secondary gear, carrying the speed and position information of the motor rotor; the magnetic induction chip is soldered onto the PCBA.

2. A robot joint module according to claim 1, characterized in that, The motor rotor end cover is provided with a hollow shaft, the output flange is provided with an output flange hollow shaft, the encoder main gear is provided with a hollow hole, and the output flange hollow shaft passes through the motor rotor end cover hollow shaft and the encoder main gear hollow hole.

3. A robot joint module according to claim 2, characterized in that, The stop of the encoder main gear and the stop of the hollow shaft in the rotor end cover of the motor assembly have a concave-convex fit structure.

4. A robot joint module according to claim 2, characterized in that, The hollow shaft of the output flange is provided with a first oil seal, the inner ring of which is interference-fitted with the outer ring of the hollow shaft of the output flange; the upper and lower end faces of the first oil seal are respectively in contact with the outer end face of the rotor end cover and the inner end face of the output flange.

5. A robot joint module according to claim 1, characterized in that, The encoder assembly is fixed to the flange base by a third screw. The inner ring of the encoder housing and the outer ring of the flange base are coaxially fitted. The inner end face of the encoder housing is in contact with the end face of the flange base. The upper and lower end faces of the second oil seal are in contact with the inner end face of the flange base and the end face of the rotor housing, respectively.

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