Robot joint module zero position and mechanical limiting structure
By using the limit pins and zero pins in conjunction with the arc-shaped limit groove on the outer ring of the bearing, combined with the labyrinth seal structure and roller bearings, the problems of high cost, poor anti-interference and sealing of limit and zero calibration of robot joint modules are solved, achieving compact design and high-precision operation.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-23
- Publication Date
- 2026-03-17
AI Technical Summary
Existing methods for calibrating the limit and zero positions of robot joint modules suffer from high costs, poor anti-interference capabilities, complex structures, large space requirements, and easy wear of sealed designs, making it difficult to meet the needs of compact designs.
By using limit pins and zero pins in conjunction with the arc-shaped limit groove on the outer ring of the bearing, the mechanical limit and zero calibration are physically integrated. Combined with the labyrinth seal structure and roller bearing, the assembly complexity is reduced and the anti-interference and sealing performance are improved.
It achieves compact structure, low cost, and strong anti-interference mechanical limit and zero-position calibration, improves the repeatability and reliability of the module, and reduces the risk of lubricant leakage.
Smart Images
Figure CN223998429U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of robot joint module technology, and in particular relates to a zero-position and mechanical limiting structure for a robot joint module. Background Technology
[0002] As a core driving component of industrial robots, collaborative robots, and service robots, the performance of robot joint modules directly determines the robot's motion accuracy, load capacity, and reliability. Zero-position calibration and mechanical limit structures are key technologies in joint module design, directly affecting the module's repeatability and safe operation. In existing technologies, joint modules typically achieve limit and zero-position functions in two ways: one is by detecting the rotational position through external photoelectric sensors or Hall elements, combined with software control to achieve electronic limiting; the other is a purely mechanical structure using mechanical stops and limit screws. However, the former suffers from high cost and poor anti-interference capabilities, especially susceptible to interference in complex electromagnetic environments; the latter, due to its complex structure and large space occupation, is difficult to meet the design requirements of compact joint modules. Furthermore, the sealing design in existing mechanical limit structures often uses a single sealing ring, which is prone to lubricant leakage due to wear during high-speed operation or long-term use, thus affecting the lifespan of harmonic reducers and bearings. Utility Model Content
[0003] To address the aforementioned technical problems, the purpose of this utility model is to provide a zero-position and mechanical limiting structure for a robot joint module. This structure is compact, low in cost, and convenient for zero-position calibration.
[0004] To achieve the above-mentioned objectives, this utility model adopts the following technical solution:
[0005] A robot joint module zero-position and mechanical limiting structure includes a motor assembly and a harmonic reducer. The motor assembly includes a housing, a stator assembly, and a rotor assembly. The stator assembly is fixed to the inner wall of the housing, and the rotor assembly is disposed within the stator assembly and rotatably connected to the housing at both ends.
[0006] The harmonic reducer includes a wave generator, a flexible wheel, a steel wheel, a support bearing, and an output disc. The support bearing includes an inner bearing ring and an outer bearing ring. The inner bearing ring is fixed to one end of the motor assembly housing via the steel wheel. The output disc is fixed to the outer bearing ring. One end of the flexible wheel is fixed to the output disc, and the other end of the flexible wheel is driven by the steel wheel through a toothed transmission. The rotor assembly includes a rotating shaft and a rotor core. The wave generator is located at the end of the rotating shaft that extends out of the housing and is located inside the flexible wheel, driving the flexible wheel to deform.
[0007] It also includes a limit pin and a zero pin. The outer ring of the bearing is provided with an arc-shaped limit groove. One end of the housing is also provided with a connecting edge. The limit pin or zero pin is inserted on the connecting edge and extends into the arc-shaped limit groove of the outer ring of the bearing after passing through the steel wheel.
[0008] As a preferred embodiment, one end of the arc-shaped limiting groove is also provided with a zero-position positioning blind hole, the diameter of which is smaller than the diameter of the limiting pin.
[0009] As a preferred embodiment, the zero-position pin is stepped and includes two cylindrical sections with different diameters. One cylindrical section has the same diameter as the limiting pin, and the outer diameter of the other cylindrical section matches the diameter of the zero-position positioning blind hole.
[0010] As a preferred embodiment, the arc-shaped limiting groove occupies 1 / 3 to 1 / 2 of the circumference of the outer ring of the bearing.
[0011] As a preferred embodiment, a convex ring is provided on one side of the output disk, and a torque sensor is fixed inside the convex ring. The flexible wheel is fixed to the torque sensor.
[0012] As a preferred embodiment, a T-shaped shaft is fixed on the output disk. The T-shaped shaft includes a connecting disk and an intermediate tube. The connecting disk covers the outside of the convex ring. One end of the intermediate tube is fixed to the middle of the connecting disk and communicates with the connecting disk. The intermediate tube extends into the rotating shaft.
[0013] As a preferred embodiment, one end face of the housing of the motor assembly is further provided with an inner positioning ring and an outer positioning ring arranged concentrically. The side of the steel wheel that is fixed to the housing is further provided with a stepped surface and a positioning inner edge. The outer positioning ring abuts against the stepped surface, the inner positioning ring abuts against the positioning inner edge, and O-rings are provided between the inner positioning ring and the positioning inner edge, and between the outer positioning ring and the stepped surface.
[0014] As a preferred embodiment, the other side of the steel wheel is also provided with a protruding ridge, which abuts against the inner wall of the support bearing, and a sealing ring is also provided between the protruding ridge and the support bearing.
[0015] As a preferred embodiment, the support bearing is a roller bearing, and a sealing ring is provided between the outer ring and the inner ring of the bearing.
[0016] As a preferred embodiment, the other end of the motor assembly is further provided with a controller assembly.
[0017] Compared with the prior art, the beneficial effects of this utility model are as follows:
[0018] This invention achieves physical integration of mechanical positioning and zero-position calibration through the cooperation of a limiting pin and a zero-position pin with the arc-shaped limiting groove of the bearing outer ring. The design of the limiting pin penetrating the steel wheel and embedding into the groove directly constrains the rotation angle of the bearing outer ring (i.e., the output disc), eliminating the need for external sensors, resulting in a compact structure and strong anti-interference capabilities. Furthermore, the zero-position pin and the limiting pin share the same mounting position, simplifying the assembly process and reducing the complexity of multi-component calibration. Attached Figure Description
[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute a limitation thereof.
[0020] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0021] Figure 2 and Figure 3 These are two different exploded structural diagrams of this utility model.
[0022] The attached figures are labeled as follows: 1. Motor assembly; 10. Controller assembly; 11. Inner positioning ring; 12. Outer positioning ring; 2. Limiting pin; 3. Elliptical hub; 4. Flexible bearing; 5. Steel wheel; 51. Raised ridge; 52. Sealing ring; 53. Stepped surface; 54. Positioning inner edge; 6. Bearing outer ring; 61. Arc-shaped limiting groove; 62. Zero-position positioning blind hole; 63. Sealing ring; 64. Bearing inner ring; 7. Flexible wheel; 8. Output disc; 81. Raised ring; 91. Connecting disc; 92. Intermediate tube. Detailed Implementation
[0023] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. 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.
[0024] It should be noted that 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. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0025] Furthermore, in the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model.
[0026] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more, unless otherwise expressly defined.
[0027] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.
[0028] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.
[0029] The present invention will be further described below with reference to the accompanying drawings and embodiments:
[0030] like Figures 1 to 3As shown, a robot joint module includes a motor assembly 1, a harmonic reducer, a limit pin 2, and a zero-position pin. The motor assembly 1 includes a housing, a stator assembly, and a rotor assembly. The stator assembly is fixed to the inner wall of the housing, and the rotor assembly is disposed within the stator assembly, with both ends rotatably connected to the housing. A controller assembly 10 is also provided at the other end of the motor assembly 1. After integration with the motor assembly, the controller assembly directly drives the motor via an internal bus, reducing signal transmission delay to the nanosecond level. The conformal design of the controller heat sink and the motor housing increases the module's power density by more than 30% while reducing external electromagnetic interference.
[0031] The harmonic reducer includes a wave generator, a flexible wheel 7, a steel wheel 5, a support bearing, and an output disc 8. The support bearing includes an inner bearing ring 64 and an outer bearing ring 6. The inner bearing ring 64 is fixed to one end of the housing of the motor assembly 1 via the steel wheel 5. The output disc 8 is fixed to the outer bearing ring 6. One end of the flexible wheel 7 is fixed to the output disc 8, and the other end of the flexible wheel 7 is located inside the steel wheel 5. The rotor assembly includes a rotating shaft and a rotor core. The wave generator includes an elliptical hub 3 and a flexible bearing 4. The elliptical hub 3 is fixed to one end of the rotating shaft that extends out of the housing and is disposed inside the flexible wheel 7 via the flexible bearing 4, driving the flexible wheel 7 to deform; thereby enabling the flexible wheel 7 and the steel wheel 5 to perform staggered gear transmission.
[0032] The zero-position and mechanical limiting structure of the above-mentioned robot joint module is as follows: the outer ring 6 of the bearing is provided with an arc-shaped limiting groove 61, and one end of the housing is also provided with a connecting edge. The limiting pin 2 or the zero-position pin is inserted on the connecting edge and extends into the arc-shaped limiting groove 61 of the outer ring 6 of the bearing after passing through the steel wheel 5.
[0033] This invention achieves physical integration of mechanical positioning and zero-position calibration through the cooperation of the limiting pin and zero-position pin with the arc-shaped limiting groove of the bearing outer ring; the design of the limiting pin penetrating the steel wheel and embedding into the groove directly constrains the rotation angle of the bearing outer ring (i.e., the output disc), without relying on external sensors, and has a compact structure and strong anti-interference ability.
[0034] One end of the arc-shaped limiting slot 61 is also provided with a zero-position positioning blind hole 62, the diameter of which is smaller than the diameter of the limiting pin 2. The zero-position pin is stepped and includes two cylindrical sections with different diameters. One cylindrical section has the same diameter as the limiting pin 2, and the outer diameter of the other cylindrical section matches the diameter of the zero-position positioning blind hole 62.
[0035] A zero-position blind hole is added at the end of the arc-shaped limiting groove, and the diameter of the blind hole is smaller than the diameter of the limiting pin to prevent the limiting pin from being mistakenly inserted into the zero-position blind hole, thus affecting the realization of the mechanical limiting function. The stepped zero-position pin adopts a two-section design with different diameters. The smaller diameter section (matching the blind hole) is used for guidance and alignment, and the larger diameter section (with the same diameter as the limiting pin) achieves final fixation. The zero-position pin and the limiting pin share the same installation position, simplifying the assembly steps and reducing the complexity of multi-component calibration.
[0036] The arc-shaped limiting groove 61 occupies 1 / 3 to 1 / 2 of the circumference of the outer ring 6 of the bearing. The above structure ensures the effective rotation range of the joint module and avoids the reduction of the stiffness of the outer ring of the bearing due to excessive groove length.
[0037] A convex ring 81 is also provided on one side of the output disk 8, and a torque sensor is fixed inside the convex ring 81. The flexible wheel 7 is fixed to the torque sensor. The convex ring of the output disk integrates a torque sensor, which is directly fixed to the end face of the flexible wheel, forming a closed force transmission path. Compared with an external sensor, this design reduces torque loss in the intermediate transmission chain, and the sensor directly contacts the deformed part of the flexible wheel, improving the dynamic torque detection response speed.
[0038] A T-shaped shaft is fixed on the output disk 8. The T-shaped shaft includes a connecting disk 91 and an intermediate tube 92. The connecting disk 91 covers the outside of the convex ring 81. One end of the intermediate tube 92 is fixed to the middle of the connecting disk 91 and communicates with the connecting disk. The intermediate tube 92 extends into the rotating shaft.
[0039] The T-shaped shaft is nested within the motor shaft via a central tube, forming a "shaft-in-shaft" structure. The snap-on design of the connecting disc and the convex ring disperses radial forces, reducing deflection of the output disc under eccentric loads. The through-tube design facilitates wiring (such as sensor signal lines) and avoids the risk of external cable entanglement.
[0040] The motor assembly 1 is provided with an inner positioning ring 11 and an outer positioning ring 12 arranged concentrically on one end face of its housing. The steel wheel 5 is also provided with a stepped surface 53 and a positioning inner edge 54 on the side fixed to the housing. The outer positioning ring 12 abuts against the stepped surface 53, and the inner positioning ring 11 abuts against the positioning inner edge 54. O-rings are provided between the inner positioning ring 11 and the positioning inner edge 54, and between the outer positioning ring 12 and the stepped surface 53.
[0041] The inner and outer locating rings, along with the stepped surfaces and inner locating edges of the steel wheel, form a labyrinthine sealing structure. With the O-rings in place, the sealing rating reaches IP67, effectively preventing grease leakage from the harmonic reducer. Simultaneously, the interference fit of the locating rings eliminates assembly clearance between the steel wheel and the housing, reducing the probability of misalignment in the harmonic drive.
[0042] The steel wheel 5 also has a protruding ridge 51 on its other side, which abuts against the inner wall of the supporting bearing, and a sealing ring 52 is provided between the protruding ridge 51 and the supporting bearing. The protruding ridge on the side of the steel wheel and the inner wall of the supporting bearing form an axial sealing surface, which, together with the sealing ring, prevents external dust from entering the bearing raceway.
[0043] The support bearing is a roller bearing, and a sealing ring 63 is provided between the outer ring 6 and the inner ring 64. Replacing the traditional deep groove ball bearing with a roller bearing increases the axial load capacity of the support bearing by 2 to 3 times. The sealing ring is made of fluororubber, with a temperature resistance range extended to -40℃ to 150℃, suitable for high-speed or alternating high and low temperature operating conditions.
[0044] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0045] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.
Claims
1. A robot joint module zero position and mechanical limit structure, comprising a motor assembly (1) and a harmonic reducer, the motor assembly (1) comprising a shell, a stator assembly fixed on the inner wall of the shell, and a rotor assembly arranged in the stator assembly and rotationally connected to the shell at both ends, the harmonic reducer comprising a wave generator, a flexspline (7), a steel wheel (5), a support bearing comprising a bearing inner ring (64) and a bearing outer ring (6), and an output disc (8), the bearing inner ring (64) being fixed at one end of the shell of the motor assembly (1) through the steel wheel (5), the output disc (8) being fixed with the bearing outer ring (6), one end of the flexspline (7) being fixed with the output disc (8), the other end of the flexspline (7) being in gear transmission with the steel wheel (5), the rotor assembly comprising a rotating shaft and a rotor core, the wave generator being arranged at one end of the rotating shaft penetrating the shell and located in the flexspline (7) to drive the flexspline (7) to deform; characterized in that further comprising a limit pin (2) and a zero position pin, the bearing outer ring (6) being provided with an arc-shaped limit slot (61), one end of the shell being further provided with a connecting edge, the limit pin (2) or the zero position pin being inserted on the connecting edge and extending through the steel wheel (5) and into the arc-shaped limit slot (61) of the bearing outer ring (6).
2. The robot joint module zero position and mechanical limit structure according to claim 1, characterized in that, One end of the arc-shaped limit slot (61) is further provided with a zero position positioning blind hole (62), the diameter of the zero position positioning blind hole (62) being smaller than the diameter of the limit pin (2).
3. The robot joint module zero position and mechanical limit structure according to claim 2, characterized in that, The zero position pin is in a stepped shape and comprises two cylindrical sections with different diameters, one of which has the same diameter as the limit pin (2) and the other of which has an outer diameter matching the diameter of the zero position positioning blind hole (62).
4. The robot joint module zero position and mechanical limit structure of claim 1, wherein, The arc-shaped limit slot (61) accounts for 1 / 3 to 1 / 2 of the circumference of the bearing outer ring (6).
5. The robot joint module zero position and mechanical limit structure according to claim 1, characterized in that, One side of the output disc (8) is further provided with a convex ring (81), a torque sensor is further fixed in the convex ring (81), and the flexspline (7) is fixed with the torque sensor.
6. The robot joint module zero position and mechanical limit structure of claim 5, wherein, A T-shaped shaft is fixed on the output disc (8), the T-shaped shaft comprising a connecting disc (91) and an intermediate tube (92), the connecting disc (91) being buckled outside the convex ring (81), one end of the intermediate tube (92) being fixed in the middle of the connecting disc (91) and penetrating the connecting disc, and the intermediate tube (92) extending into the rotating shaft.
7. The robot joint module zero position and mechanical limit structure of claim 1, wherein: One end surface of the shell of the motor assembly (1) is further provided with an inner positioning ring (11) and an outer positioning ring (12) arranged concentrically, one side of the steel wheel (5) fixed with the shell is further provided with a stepped surface (53) and a positioning inner edge (54), the outer positioning ring (12) abutting against the stepped surface (53), the inner positioning ring (11) abutting against the positioning inner edge (54), and O-shaped sealing rings being arranged between the inner positioning ring (11) and the positioning inner edge (54) and between the outer positioning ring (12) and the stepped surface (53).
8. The robot joint module zero position and mechanical limit structure according to claim 7, characterized in that: The other side of the steel wheel (5) is further provided with a convex rib (51), the convex rib (51) abutting against the inner side wall of the support bearing, and a sealing ring (52) being further arranged between the convex rib (51) and the support bearing.
9. The robot joint module zero position and mechanical limit structure of claim 1, wherein, The support bearing is a roller bearing, and a sealing ring (63) is further arranged between the bearing outer ring (6) and the bearing inner ring (64).
10. The robot joint module zero position and mechanical limit structure of claim 1, wherein, The other end of the motor assembly (1) is further provided with a controller assembly (10).