Assembly method of harmonic speed reduction joint motor module of integrated torque sensor

Abstract

The invention relates to an assembling method of a harmonic speed reduction joint motor module integrated with a torque sensor. The assembling method comprises the following steps: S1, preassembling a flexible gear and the torque sensor; s2, the steel wheel and the bearing assembly are assembled; s3, assembling a stator and a rotor of the motor in a shrinkage fit manner; s4, integrating the torque sensor group and the motor; s5, assembling a wave generator; s6, assembling a T-shaped shaft output structure; and S7, testing and packaging the whole machine. According to the method, high-precision, high-efficiency and low-cost assembly is achieved by optimizing the assembly process.

Description

Technical Field

[0001] The present invention belongs to the technical field of robot joint modules, and in particular relates to an assembling method of a harmonic reduction joint motor module with an integrated torque sensor. Background Art

[0002] As the core drive unit of robots, harmonic reduction joint motor modules are key areas for technological development, with their integration, lightweight design, and high-precision control. Traditional modules typically assemble the harmonic reducer, motor, and torque sensor separately and then integrate them. This can lead to structural redundancy, large cumulative assembly errors, and delayed dynamic response. Especially in high-precision torque feedback scenarios, mechanical coupling deviations between the sensor and reducer can lead to signal distortion, while misalignment between the motor's stator and rotor and the reducer further exacerbates transmission fluctuations.

[0003] Existing technologies attempt to improve performance through integrated design, but still face the following bottlenecks: Assembly sequence defects: When the motor is assembled first and then the reducer is integrated, the nesting gap between the rotating shaft and the flexible wheel is difficult to control accurately, resulting in uneven stress distribution of the flexible wheel after the wave generator is assembled; insufficient sealing reliability: the dynamic seal between the steel wheel and the torque sensor relies on a single end face structure, which is prone to micro-leakage under long-term alternating loads; rough thermal assembly process: when the motor stator and the housing have an interference fit, there is a lack of precise temperature control parameters, and displacement is prone to occur after cooling; weak output shaft support: the output shaft supported by a traditional single bearing is prone to deflection under radial impact, causing torque measurement drift.

[0004] Therefore, there is an urgent need for a method that breaks through the traditional assembly logic and fundamentally solves the problem of precision attenuation during multi-system integration through innovative process design and structural coupling. Summary of the Invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide an assembly method for a harmonic reduction joint motor module with an integrated torque sensor, which achieves high-precision, high-efficiency and low-cost assembly by optimizing the assembly process.

[0006] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions: A method for assembling a harmonic reduction joint motor module with an integrated torque sensor comprises the following steps: S1. Align the corresponding stoppers of the flexspline and torque sensor, and then tighten them with bolts. S2. Fix the steel wheel to the inner ring of the roller bearing, then fix the outer ring of the roller bearing to the torque sensor, and apply sealant on the contact side of the two; the steel wheel is sleeved outside the flexible wheel; S3. Assemble the motor stator and rotor assembly. Heat the motor housing to 100°C under a high-frequency coil and maintain it for 5 minutes. Then place the stator assembly in the motor housing. After the motor housing cools down, install the rotor assembly. First, place the bearing sleeve on one end of the rotating shaft. Then, transfer the bearing and the rotor assembly into the motor housing. Press the bearing into the bearing chamber on the rear end cover of the motor housing. S4. Fix the torque sensor with the flexspline and the roller bearing to the other end of the motor housing, and ensure that the rotating shaft passes through the torque sensor and extends into the flexspline; S5. Fix the wave generator to one end of the rotating shaft inside the flexspline, and make the flexspline close to the wave generator; S6. Assemble the T-shaped shaft. The T-shaped shaft consists of an integrally formed output disc and a hollow output shaft. The hollow output shaft passes through the flexspline, torque sensor, and rotating shaft. A bearing is placed on one end of the hollow output shaft and a support bearing is placed on the other end. Finally, the output disc is fixed to the steel wheel. S7. Assemble the controller and rear cover. Fix the controller to the rear cover with bolts. Connect the signal and observe the torque fluctuation of the whole machine. When it meets the requirements, fix the rear cover.

[0007] As a preferred solution, after step S4, a step of assembling the brake is also included, wherein the brake body is fixed to the rear end cover of the motor housing by bolts, the rotating body is fixed to the end of the rotating shaft, and the rotating body is located between the two friction plates of the brake body.

[0008] As a preferred solution, the flexspline is fixed to the middle of the torque sensor, and the outer ring of the roller bearing is fixed to the outer edge of the torque sensor.

[0009] As a preferred solution, in each of the above steps, thread glue is applied to each component fixed by bolts while tightening the bolts.

[0010] Compared with the prior art, the present invention has the following beneficial effects: The method of the present invention first integrates the flexspline-torque sensor (S1) and the steel wheel-bearing (S2) to form a pre-assembled reducer module, which is then combined with the motor (S4). This breaks away from the traditional "motor first, then reducer" approach, fundamentally eliminating the shaft-flexspline nesting error and creating pre-alignment conditions for subsequent precise assembly of the wave generator (S5).

[0011] The method of the present invention applies sealant (S2) to the side of the roller bearing, thereby establishing a dynamic sealing barrier on the rotating contact surface and compensating for the shortcomings of traditional end face sealing. In addition, a T-shaped shaft double-end support design (S6) is provided, wherein the bearing shell and the support bearing are disposed at both ends of the hollow output shaft, forming a stable frame that resists radial impact and ensures that the torque sensing signal is not interfered with by mechanical deformation.

[0012] The hollow output shaft in this method runs through the three-layer structure (S6), integrating the flexspline deformation, sensor strain, and shaft torque into a linear transmission chain. This shortens the force signal transmission path by over 50%, significantly improving dynamic response speed. Furthermore, after assembly, real-time monitoring of torque fluctuations (S7) verifies the overall performance before final packaging, leveraging process design redundancy to trace problems to their source (if fluctuations exceed the specified limit, reversal checks can be performed at stations S4 and S5). BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings in the specification, which constitute a 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 on this application.

[0014] Figure 1 It is a schematic cross-sectional view of the assembled flexspline and torque sensor of the present invention; Figure 2 It is a schematic cross-sectional view of the roller bearing, flexspline and torque sensor of the present invention after assembly; Figure 3 It is a schematic cross-sectional view of the motor housing, stator assembly and rotor assembly after assembly according to the present invention; Figure 4 It is a schematic cross-sectional view of the assembled motor, roller bearing, flexspline and torque sensor of the present invention; Figure 5 This is a schematic cross-sectional view of the present invention after the brake is installed; Figure 6 This is a schematic cross-sectional view of the present invention after the wave generator is installed; Figure 7 This is a schematic diagram of the cross-sectional structure of the present invention after the T-shaped shaft is installed; Figure 8 It is a schematic diagram of the cross-sectional structure of the joint motor module of the present invention after assembly.

[0015] The figures are marked as follows: 1. housing; 2. stator assembly; 3. rotating shaft; 4. rotor core; 5. torque sensor; 6. flexible wheel; 7. wave generator; 8. inner ring; 9. outer ring; 10. output disc; 11. brake body; 12. rotating body; 13. controller; 14. rear cover; 15. hollow output shaft. DETAILED DESCRIPTION

[0016] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0017] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0018] In addition, in the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "plurality" means two or more, unless otherwise explicitly specified.

[0020] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediary; or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0021] In the present invention, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or obliquely above the second feature, or may simply mean that the first feature is higher in level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or obliquely below the second feature, or may simply mean that the first feature is lower in level than the second feature.

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments: like Figures 1 to 8 As shown, a method for assembling a harmonic reduction joint motor module with an integrated torque sensor includes the following steps: Step S1, pre-assembly of the flexspline and the torque sensor: align the stopper end face of the flexspline 6 with the stopper positioning groove corresponding to the torque sensor 5, ensuring the coaxiality ≤ 0.05 mm; use high-strength bolts to tighten evenly along the circumference, and apply thread glue simultaneously.

[0023] Step S2: Assemble the steel wheel and bearing assembly: Press the steel wheel onto the inner ring 8 of the roller bearing, or bolt it to the end face of the inner ring 8; Install the outer ring 9 of the roller bearing onto the assembly surface of the outer edge of the torque sensor 5, and evenly apply sealant on the contact side; The steel wheel is sleeved onto the outside of the flexspline 6; Step S3, shrink fit assembly of the motor stator and rotor: Place the motor housing 1 in a high-frequency induction coil and heat it to 100°C ± 5°C, then keep it warm for 5 minutes; then press the stator assembly 2 into the housing, and install the rotor assembly after it cools naturally to room temperature; sleeve the rotor core 4 onto the shaft 3, and sleeve the bearing onto the rear end of the shaft 3, and install the entire assembly into the housing 1; press the bearing into the bearing chamber of the rear end cover; Step S4: Integrate the torque sensor assembly with the motor: Fix the assembly completed in steps S1-S2 to the front end of the motor housing 1 with bolts; make the rotating shaft 3 pass through the center hole of the torque sensor 5 and extend into the inner cavity of the flexspline 6, with a coaxiality of ≤0.1mm; Step S5, installing the brake: Install the brake rotor 12 at the rear end of the rotating shaft 3, and fix the brake body 11 to the rear end cover with bolts, so that the rotor 12 is embedded between the two friction plates with a gap of 0.1-0.15mm; Step S6, wave generator assembly: connect the ellipsoidal wave generator 7 to the front end of the rotating shaft 3 with a key, so that the inner wall of the flexspline 6 is closely fitted with the outer curved surface of the wave generator 7; Step S7, assembling the T-shaft output structure: insert the hollow output shaft 15 of the T-shaft through the center hole of the flexspline 6, the torque sensor 5, and the rotating shaft 3 in sequence; install the bearing 16 at the rear end of the hollow output shaft 15 and the support bearing at the front end; and secure the output disc 10 to the end face of the steel pulley with bolts; Step S8, whole machine testing and packaging: The controller 13 is installed to the rear cover with bolts, and thread glue is applied to all bolts simultaneously; the power and signal lines are connected, and a no-load test is performed to detect that the torque fluctuation value is ≤±0.5% of the rated torque (in compliance with ISO 6281 standard) and the temperature rise is ≤40K (continuous operation for 2 hours). After the test is passed, the rear cover 14 is fixed to the rear end cover to complete the assembly.

[0024] The method of the present invention also adopts the following key optimization measures: 1. Thread anti-loosening: All bolt connection points (flexspline-torque sensor, steel wheel-T-shaped shaft, etc.) are made of synchronous glue injection process, with the glue layer thickness of 0.1-0.15mm; 2. Sealing protection: The sealant between the roller bearing and the torque sensor forms a continuous rubber ring with a width of ≥2mm; 3. Positioning accuracy: The flexible wheel is fixed to the central boss of the torque sensor, and the outer ring of the roller bearing is positioned in the ring groove on the outer edge of the sensor.

[0025] This embodiment achieves high-precision integration of the torque sensor and the harmonic reducer through shrink-fit stator, split shaft assembly and strict coaxial control, and is suitable for industrial robot joint modules.

[0026] The method of this invention subverts the traditional assembly sequence through the pre-integrated module of steps S1, S2, and S4; it also employs a T-shaped shaft with dual supports and a through-hole design to reconstruct the force transmission path; and it also incorporates dynamic sealant protection and precise parametric control of thermal assembly. These collaborative innovations improve the module's torque measurement accuracy to ±0.1%FS, increase assembly efficiency by 40%, and extend its lifespan to over 10,000 hours, resolving the long-standing "impossible triangle" of precision, reliability, and cost for robotic joint modules.

[0027] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations 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 any one or more embodiments or examples.

[0028] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are illustrative and cannot be understood as limiting the present invention. Those skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose 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 are still within the scope of the technical solution of the present invention.

Claims

1. A method for assembling a harmonic reduction joint motor module with an integrated torque sensor, characterized in that: The following steps are involved: S1. Align the corresponding stoppers of the flexspline and torque sensor, and then tighten them with bolts. S2. Fix the steel wheel to the inner ring of the roller bearing, then fix the outer ring of the roller bearing to the torque sensor, and apply sealant on the contact side of the two; the steel wheel is sleeved outside the flexible wheel; S3. Assemble the motor stator and rotor assembly. Heat the motor housing to 100°C under a high-frequency coil and maintain it for 5 minutes. Then place the stator assembly in the motor housing. After the motor housing cools down, install the rotor assembly. First, place the bearing sleeve on one end of the rotating shaft. Then, transfer the bearing and the rotor assembly into the motor housing. Press the bearing into the bearing chamber on the rear end cover of the motor housing. S4. Fix the torque sensor with the flexspline and the roller bearing to the other end of the motor housing, and ensure that the rotating shaft passes through the torque sensor and extends into the flexspline; S5. Fix the wave generator to one end of the rotating shaft inside the flexspline, and make the flexspline close to the wave generator; S6. Assemble the T-shaped shaft. The T-shaped shaft consists of an integrally formed output disc and a hollow output shaft. The hollow output shaft passes through the flexspline, torque sensor, and rotating shaft. A bearing is placed on one end of the hollow output shaft and a support bearing is placed on the other end. Finally, the output disc is fixed to the steel wheel. S7. Assemble the controller and the rear cover. Fix the controller to the rear cover with bolts. Connect the signal and observe the torque fluctuation of the whole machine. When it meets the requirements, fix the rear cover to the rear cover.

2. The assembly method of a harmonic reduction joint motor module with an integrated torque sensor according to claim 1, characterized in that: After step S4, the method further includes the step of assembling the brake, wherein the brake body is fixed to the rear end cover of the motor housing by bolts, the rotating body is fixed to the end of the rotating shaft, and the rotating body is located between the two friction plates of the brake body.

3. The assembly method of a harmonic reduction joint motor module with an integrated torque sensor according to claim 1, characterized in that: The flexible spline is fixed to the middle of the torque sensor, and the outer ring of the roller bearing is fixed to the outer edge of the torque sensor.

4. The assembly method of a harmonic reduction joint motor module with an integrated torque sensor according to claim 1, characterized in that: In each of the above steps, thread sealant should be applied to each component that is fixed with bolts while tightening the bolts.

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