High-rigidity high-output humanoid robot linear joint module

Abstract

A high-rigidity and high-output humanoid robot linear joint module, comprising a shell assembly, a driving transmission mechanism, a bearing support system, an anti-rotation limiting assembly, a position detection assembly, a control assembly and a joint bearing assembly. The driving transmission mechanism adopts a reverse planetary roller screw and a frameless torque motor direct drive structure, and the roller, the screw and the nut form a linear contact transmission. The bearing support system is composed of back-to-back angular contact ball bearings and deep groove ball bearings to realize all-around force support. The anti-rotation limiting assembly prevents circumferential rotation through the copper sleeve square hole and the flat position of the screw. The position detection assembly realizes high-precision detection through magnetic ring adhesion fixation, installation seat axial positioning and gasket gap adjustment. The control assembly adopts a two-piece stacked drive control board design with compact structure. The module significantly improves the load capacity, positioning accuracy and impact resistance, and is compact, maintenance-free and suitable for the high-load, high-precision and high-dynamic linear drive requirements of humanoid robots.

Description

Technical Field

[0001] This utility model belongs to the field of humanoid robot joint drive technology, and relates to a high-rigidity, high-output, and high-precision humanoid robot linear joint module, which is suitable for key motion mechanisms such as leg extension and retraction and arm lifting of humanoid robots. It can meet the motion requirements of high load, high dynamics, and high precision, and provide stable and reliable linear drive force for robot limbs. Background Technology

[0002] With the integration of artificial intelligence and intelligent manufacturing technologies, humanoid robots, as the ultimate carrier of general artificial intelligence, are rapidly moving from laboratory research and development to industrial applications. The joint drive system of a humanoid robot is a core technological unit that determines its motion performance, load capacity, dynamic response, and reliability. Currently, humanoid robot joint drive methods are mainly divided into two categories: rotary joints and linear joints. Among them, linear joints, due to their advantages such as direct drive, high rigidity, high precision, and zero backlash, have irreplaceable application value in key areas such as lower limb leg drive, trunk extension and retraction, and ankle joint variable stiffness.

[0003] In existing technologies, the transmission schemes for linear joint modules are mainly divided into two categories: ball screw transmission and planetary roller screw transmission, but both have obvious technical defects. CN120246123A discloses a linear joint module for legged robots, which uses a ball screw mechanism in conjunction with a guide shaft assembly to achieve linear drive, and introduces a lubrication source through a flow channel to improve friction. However, the core defect of this scheme is that the ball of the ball screw has point contact with the screw and nut, resulting in a small force-bearing area. Under heavy load or impact conditions, ball wear and screw deformation are prone to occur, which limits the load-bearing capacity and cannot meet the high output requirements of humanoid robot limb drive. At the same time, the guide mechanism adopts a ring array of multiple guide shaft assemblies, which improves the guiding accuracy, but increases the structural complexity and radial dimensions, making the module "short and thick", which does not meet the bionic design of humanoid robots and the installation requirements of the small internal space. In addition, this scheme does not optimize the position detection structure, resulting in a large positioning error and making it difficult to meet the requirements of high-precision motion control.

[0004] CN222741484U discloses a robot linear joint module that uses a reverse planetary roller screw mechanism to improve transmission performance and integrates the bearing inner ring and nut tube into a single design to reduce size. However, this technology still has significant shortcomings: it relies on coolant for heat dissipation under high loads, requiring additional cooling plates and injection ports, which not only increases the overall weight and assembly difficulty of the module but also poses a potential risk of coolant leakage; the control circuit board uses a double-layer plug-in structure, resulting in poor connection stability under vibration conditions during robot dynamic motion and a tendency to experience signal interruption failures; the positioning structure of the encoder and magnetic ring is not optimized, resulting in insufficient position detection accuracy and making it unsuitable for high-precision motion scenarios of humanoid robots; at the same time, the assembly method of the joint bearings leads to weak impact resistance, making them prone to damage under instantaneous impact loads and affecting the module's service life.

[0005] CN120962634A discloses a linear actuator for a linear joint module, which improves positioning accuracy through a dual-sensor assembly and adds a braking mechanism to solve the problem of maintaining posture after power failure. However, this solution still has obvious shortcomings: the braking mechanism includes multiple parts such as a braking stator, a braking rotor, and elastic washers, which occupy a large axial space, increasing the overall length of the module and limiting its adaptability; the connecting bearing uses a fisheye bearing, which has insufficient impact resistance under high load conditions and is prone to deformation; the sensor assembly transmits motion through rack and pinion meshing, and after long-term use, mechanical wear will lead to accuracy decay, increasing maintenance costs.

[0006] In summary, existing linear joint modules generally suffer from common defects such as limited load-bearing capacity, low positioning accuracy, weak impact resistance, unreasonable structural layout, and high maintenance costs. These defects make it difficult to meet the requirements of humanoid robots for high load, high precision, high speed, compact structure, and maintenance-free operation. There is an urgent need to develop a new type of linear joint module to overcome the above-mentioned technical bottlenecks. Summary of the Invention

[0007] The purpose of this invention is to overcome the aforementioned deficiencies of the prior art and provide a high-load integrated linear joint module for humanoid robots. Through the innovative integration of a reverse planetary roller screw and frameless torque motor direct drive technology, optimized differentiated bearing support configuration, a unique four-hole anti-rotation limiting structure, and a highly integrated drive and control design, it achieves a comprehensive improvement in load-bearing capacity, transmission accuracy, dynamic response speed, and impact resistance, meeting the stringent requirements of high-load joints such as the legs and hips of humanoid robots. This invention achieves its purpose through the following specific technical solutions.

[0008] A high-rigidity, high-output humanoid robot linear joint module includes: The housing assembly includes a housing, a front cover, a rear cover, and a bearing housing, which are detachably connected to form a closed housing. The drive transmission mechanism includes a reverse planetary roller screw and a frameless torque motor sleeved on the outside of its nut; The bearing support system includes a pair of angular contact ball bearings arranged back to back and a deep groove ball bearing, which are respectively installed on opposite sides of the reverse planetary roller screw and are both assembled in the bearing housing. The anti-rotation limiting component includes a copper sleeve fitted on the lead screw of the reverse planetary roller screw, and the copper sleeve is provided with a limiting hole that matches the flat position on the lead screw. The position detection component includes a magnetic ring fixed on a mounting base and an encoder PCB board disposed opposite to the magnetic ring. The mounting base is fixed to the end of the reverse planetary roller screw. The control component includes a motor drive control board, which includes a control board and a power board, and is mounted on the bearing housing; The spherical bearing assembly includes two spherical bearings, which are respectively mounted on the rear cover plate and the screw extension end of the reverse planetary roller screw.

[0009] This utility model constructs a high-load core through "reverse planetary roller screw + frameless torque motor direct drive", and is equipped with an all-round support structure of "back-to-back angular contact bearing + deep groove ball bearing". Combined with the anti-rotation design of copper sleeve and screw flat position, it improves the module output force, rigidity and stability from multiple dimensions of transmission, support and anti-torsion. The structure is compact and suitable for the linear drive requirements of humanoid robots.

[0010] Furthermore, the reverse planetary roller screw includes a screw body, a nut, and multiple rollers distributed between the two. The contact surfaces between the rollers and the screw body and the nut are line contacts. Compared to the point contact of traditional ball screws, line contact significantly increases the force-bearing area, reduces contact stress, and greatly improves transmission load capacity, rigidity, and fatigue life, making it suitable for high-frequency, high-impact dynamic robot scenarios.

[0011] Furthermore, the stator of the frameless torque motor is fixed inside the housing, and its rotor is sleeved and fixed to the outside of the nut of the reverse planetary roller screw, with the stator and rotor arranged coaxially. The integrated structure of the rotor direct-drive nut eliminates intermediate transmission links, shortens the transmission chain, improves transmission efficiency, response speed, and control accuracy, while also simplifying the structural volume.

[0012] Furthermore, it also includes a lead screw limit rod, which is sleeved on the lead screw of the reverse planetary roller lead screw and passes through the limiting hole of the copper sleeve, with one end abutting against the lead screw body. The lead screw limit rod and the limiting hole of the copper sleeve form a double anti-rotation structure, ensuring that the lead screw only performs pure axial movement without circumferential movement, while dispersing impact loads and enhancing motion rigidity and positioning accuracy.

[0013] Furthermore, the mounting base is fixed to the end of the reverse planetary roller screw by a set screw, and the mating point between the mounting base and the screw is provided with a stepped structure for axial positioning. This stepped structure enables precise axial positioning of the mounting base, ensuring the initial clearance accuracy between the magnetic ring and the encoder PCB board, thus laying a mechanical foundation for high-precision position detection.

[0014] Furthermore, the encoder PCB board is fixed to the bearing housing via a connector, and the gap between the encoder PCB board and the magnetic ring is adjustable. This allows for flexible adjustment of the air gap between the magnetic ring and the encoder PCB board, optimizing the magnetic signal detection intensity, ensuring the stability and accuracy of position detection, and facilitating subsequent maintenance and debugging.

[0015] Furthermore, the motor drive control boards are arranged in a stacked manner and fixed to the bearing housing by support members. The stacked arrangement saves axial space, and the support members serve both fixing and heat dissipation functions, improving module integration, realizing electromechanical integration design, and adapting to narrow installation spaces.

[0016] Furthermore, the pair of back-to-back angular contact ball bearings and the deep groove ball bearing are pre-tightened and fixed within the bearing housing by locking components. This pre-tightening design eliminates internal bearing clearance, improves the rigidity of the bearing system, effectively counteracts the support reaction force during screw operation, and ensures stability under high-speed motion.

[0017] Furthermore, the spherical bearing is a self-lubricating spherical bearing, with its inner ring having a clearance fit with the mating parts. The self-lubricating structure requires no additional lubricant, achieving a maintenance-free design. The clearance fit ensures reliable connection, absorbs installation errors and minor off-center loads, and protects internal precision transmission components.

[0018] Furthermore, the connecting surfaces of the outer shell, front cover, bearing housing, and rear cover are precisely fitted, ensuring the overall shell maintains coaxiality. This high-precision shell assembly design ensures the coaxiality accuracy of internal transmission components, reduces mechanical friction and electromagnetic interference, and guarantees long-term stable operation of the module.

[0019] Compared with the prior art, this utility model has the following beneficial technical effects: (1) The load capacity is greatly improved: the rollers of the reverse planetary roller screw are in line contact with the screw body and nut. The force-bearing area is 3-5 times larger than the point contact of the traditional ball screw, and the contact stress is significantly reduced. Combined with the high torque output of the frameless torque motor, the load-bearing capacity of the module is qualitatively improved, which can meet the high output requirements of the humanoid robot limb drive and solve the technical bottleneck of insufficient load capacity of the existing ball screw joint. (2) The positioning accuracy is significantly improved: the axial positioning of the magnetic ring is realized through the stepped structure of the mounting seat and the top screw positioning. Combined with the adjustable encoder PCB board mounting structure, the position detection error is greatly reduced. At the same time, the pre-tightening design of the bearing support system eliminates the bearing clearance, and the anti-rotation limit component restricts the circumferential movement of the screw. The synergistic effect of multiple structures ensures the high-precision positioning of the linear motion of the screw and ensures the accuracy of the robot's action. (3) Strong impact resistance: The line contact structure of the reverse planetary roller screw itself has stronger impact resistance. Combined with the impact dispersion effect of the screw limit rod, the module can withstand large instantaneous impact loads, avoiding the problem of ball screws or joint bearings being easily damaged under impact in the existing technology, and is suitable for high dynamic scenarios of sudden movement or collision of humanoid robots. (4) Compact structure and good adaptability: The integrated structure of frameless torque motor rotor direct drive nut is adopted, eliminating the intermediate transmission link; the motor drive control board adopts a stacked arrangement, which greatly reduces the axial space occupied; the shell components are made of high-strength lightweight materials, which achieves lightweight design while ensuring structural strength. The overall structure is compact and small in size, which can perfectly adapt to the narrow installation space inside the humanoid robot and meet the requirements of bionic design. (5) High operational stability: The back-to-back angular contact ball bearings can simultaneously withstand large axial and radial forces. Combined with the radial force bearing of the deep groove ball bearings, a comprehensive force support system is formed, which effectively offsets the support reaction force generated during the operation of the lead screw and reduces vibration during operation. The anti-rotation limit component ensures that the lead screw only performs pure axial movement, avoiding motion deviation caused by circumferential movement, so that the module can still maintain stable operation under high-speed motion conditions. (6) Maintenance-free and long service life: The joint bearing adopts a self-lubricating structure, which does not require additional lubricant and reduces maintenance workload. The line contact transmission structure reduces the wear of transmission components. The low friction design of the frameless torque motor reduces energy loss. Combined with the good heat dissipation performance of the shell components, the continuous working time of the module is greatly extended, and the service life is significantly improved compared with the existing technology, reducing the use and maintenance costs of humanoid robots. (7) Convenient assembly and maintenance: The outer casing components adopt a detachable connection method, and the drive control board, encoder PCB board and other components are fixed by connectors, which facilitates disassembly and maintenance; the standardized design and precise matching of each component improves assembly efficiency, reduces assembly error, and also provides convenience for later maintenance and replacement. Attached Figure Description

[0020] Figure 1 is a three-dimensional structural diagram of the linear joint module of the high-rigidity, high-output humanoid robot of this utility model; Figure 2 is a cross-sectional structural diagram of the linear joint module of the high-rigidity, high-output humanoid robot of this utility model; In the figures: 1-joint bearing, 2-nut, 3-screw limit rod, 4-copper sleeve, 5-front end cover, 6-outer shell, 7-angular contact ball bearing, 8-frameless torque motor, 9-reverse planetary roller screw, 10-bearing seat, 11-deep groove ball bearing, 12-mounting seat, 13-magnetic ring, 14-encoder PCB board, 15-control board, 16-power board, 17-rear end cover, 18-locking nut. Detailed Implementation

[0021] The technical solution of this utility model will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the protection scope of this utility model.

[0022] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and 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, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance, quantity, or position.

[0023] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" 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.

[0024] A high-rigidity, high-output humanoid robot linear joint module, as shown in Figures 1 and 2, includes a shell assembly, a drive transmission mechanism, a bearing support system, an anti-rotation limiting assembly, a position detection assembly, a control assembly, and a joint bearing assembly. All components work together to achieve high-load, high-precision linear motion output.

[0025] I. Assembly and connection of various components (1) Assembly of the outer casing components The outer casing 6, front cover 5, rear cover 17, and bearing housing 10 are all made of high-strength, lightweight materials through CNC machining, balancing structural strength and lightweight requirements. The outer casing 6 is a hollow cylindrical structure with a stator mounting groove on the inner side for fixing the stator of the frameless torque motor 8. The front cover 5 is fixed to one end of the outer casing 6 by a detachable connector, and has a through hole in its center for the lead screw limit rod 3 to pass through. The size of the through hole is adapted to the size of the lead screw limit rod 3 to ensure clearance fit. The bearing housing 10 is positioned by a stop and fixed to the other end of the outer casing 6 with a detachable connector. It has two bearing mounting cavities machined on its inner side for assembling angular contact ball bearings 7 and deep groove ball bearings 11, respectively. The size of the mounting cavities is adapted to the outer ring of the corresponding bearings. The rear cover 17 is fixed to the outside of the bearing housing 10 by a detachable connector, and has a mounting hole in its center for mounting spherical plain bearings 1.

[0026] (2) Assembly of drive transmission mechanism The reverse planetary roller screw 9 includes a screw, a nut 2, and multiple rollers evenly distributed between them. The number of rollers is reasonably set according to the transmission requirements to ensure uniform load bearing. The stator of the frameless torque motor 8 is fixed in the stator mounting slot of the housing 6 through an transition fit or connecting piece. The rotor is fitted and fixed to the outside of the nut 2 of the reverse planetary roller screw 9 through an transition fit. The stator and rotor are arranged coaxially to ensure that the motor power can be efficiently transmitted to the nut 2.

[0027] (3) Assembly of bearing support system Two angular contact ball bearings 7 are mounted back-to-back on one side of the nut 2 of the reverse planetary roller screw 9, with their outer rings fixed in the corresponding mounting cavity of the bearing housing 10. A deep groove ball bearing 11 is mounted on one side of the screw of the reverse planetary roller screw 9, with its outer ring also fixed in the corresponding mounting cavity of the bearing housing 10. The angular contact ball bearings 7 and the deep groove ball bearing 11 are arranged at a distance from each other to form an all-round force support system. The two angular contact ball bearings 7 and the deep groove ball bearing 11 are pre-tightened by the locking nut 18. The pre-tightening force is reasonably set according to the bearing model and usage requirements to eliminate internal clearance of the bearings and improve the rigidity of the support system.

[0028] (4) Assembly of anti-rotation limit components The copper sleeve 4 is made of wear-resistant brass and is fixed to the inside of the front cover 5 by clearance fit or connector. The square hole inside it is adapted to the flat part on the screw of the reverse planetary roller screw 9. The screw limit rod 3 is made of high-strength steel, sleeved on the screw and passing through the square hole of the copper sleeve 4. One end of it abuts against the screw and the other end extends to the inside of the front cover 5. Through the cooperation between the square hole and the flat part of the screw, the circumferential rotation of the screw is restricted, ensuring that the screw only moves axially.

[0029] (5) Assembly of position detection components The magnetic ring 13 is made of high-performance permanent magnet materials such as neodymium iron boron and is fixed to the inner side of the mounting base 12 by epoxy resin adhesive. The mounting base 12 is made of high-strength steel and is fixed to the end of the reverse planetary roller screw 9 by two set screws. The mating part of the mounting base 12 and the screw has a stepped structure. By controlling the tolerance of the step size, the axial positioning of the mounting base 12 is achieved. The encoder PCB board 14 is fixed to the mounting base 12 by four copper studs and is set opposite to the magnetic ring 13. A shim is provided between the encoder PCB board 14 and the mounting base 12. By changing the shims of different thicknesses, the distance between the encoder PCB board 14 and the magnetic ring 13 is adjusted to the optimal detection range to ensure position detection accuracy.

[0030] (6) Assembly of control components Both the control board 15 and the power board 16 are made of FR-4 epoxy resin board, integrating core components such as drive chip, MCU, and position processing chip. The two are arranged in a stacked manner to achieve signal transmission through pin headers. The stacking spacing is reasonably set according to the component height to avoid component interference. The stacked control board 15 and power board 16 are fixed to the mounting base 12 by copper studs, located on the outside of the encoder PCB board 14. The copper studs have both fixing and heat dissipation functions, which can effectively dissipate the heat generated by the drive and control boards during operation.

[0031] (7) Assembly of spherical bearing assembly Both spherical plain bearings 1 are self-lubricating spherical plain bearings, which are respectively installed in the mounting hole of the rear end cover 17 and the screw extension end of the reverse planetary roller screw 9 through threaded connection. The matching tolerance is reasonably set according to the assembly requirements to ensure the reliability of the connection, while ensuring that the spherical plain bearing 1 can rotate flexibly and absorb installation errors and minor off-center loads.

[0032] II. Working principle of the module The working process of this high-rigidity, high-output humanoid robot linear joint module is as follows: Power Input: The motor drive control board receives motion commands sent by the humanoid robot's main control system and generates corresponding drive signals based on the commands. The motor drive control board includes a control board 15 and a power board 16. An external power supply powers the control board 15 and the power board 16. The control board 15 runs the motor control algorithm and control logic to output drive signals, and the power board 16 receives the drive signals and outputs voltage through a three-phase inverter bridge to control the motor rotation.

[0033] Motor drive: The motor drive control board controls the stator of the frameless torque motor 8 to generate an alternating magnetic field according to the drive signal. Under the action of the magnetic field, the rotor drives the nut 2 of the reverse planetary roller screw 9 to rotate synchronously.

[0034] Linear transmission: When nut 2 rotates, the rotational motion is converted into linear motion of the lead screw through the line contact transmission of the rollers. The extended end of the lead screw outputs linear driving force, which drives the robot limbs to complete the corresponding actions.

[0035] Force support: During the movement of the lead screw, the angular contact ball bearings 7 set back to back bear both axial and radial forces, while the deep groove ball bearings 11 assist in bearing the radial force, effectively offsetting the support reaction force generated during the operation of the lead screw and reducing vibration; the lead screw limit rod 3 and the square hole of the copper sleeve 4 cooperate to restrict the circumferential rotation of the lead screw and ensure the purity of linear motion.

[0036] Position detection: The magnetic ring 13 moves linearly synchronously with the lead screw. The encoder PCB board 14 detects the position change of the magnetic ring 13 in real time, generates a position detection signal and feeds it back to the motor drive control board. The motor drive control board adjusts the drive command according to the feedback signal to form a closed-loop control and achieve high-precision positioning.

[0037] Stable operation: The self-lubricating spherical bearing 1 reduces friction during lead screw movement, while absorbing installation errors and minor off-center loads, protecting internal precision transmission components; the locking nut 18 ensures the stability of the bearing preload state; the housing assembly provides reliable protection for all internal components; the overall structure works in concert to achieve high load, high precision, and high speed linear motion output.

[0038] III. Performance Testing and Verification A comprehensive performance test was conducted on the high-rigidity, high-output humanoid robot linear joint module of this invention. The test conditions were: ambient temperature 25℃, power supply voltage 48V, load test range 0 - rated load, and speed test range 0 - rated speed. The test results are as follows.

[0039] Load capacity: The axial load bearing capacity meets the rated design requirements, far exceeding the existing ball screw joint modules, and can meet the high output demand of humanoid robot limb drive.

[0040] Positioning accuracy: linear motion positioning error ≤0.05mm, repeatability positioning error ≤0.02mm, positioning accuracy is significantly better than existing technologies.

[0041] Operating speed: The maximum operating speed meets the rated design requirements, and the vibration amplitude is small and the stability is good during operation.

[0042] Impact resistance: It can withstand the instantaneous impact load of the rated design, and the positioning accuracy will not change significantly after the impact, and the structure will not be damaged.

[0043] Service life: After 10,000 hours of continuous operation, the wear of transmission components is minimal, and the design performance can still be maintained, with a long period of trouble-free operation.

[0044] Other performance features: Low operating noise, meeting the noise requirements of humanoid robot usage scenarios; Lightweight module with compact structure, and axial and radial dimensions meet the internal installation space requirements of humanoid robots; Self-lubricating joint bearings require no additional lubrication and have a long maintenance-free cycle.

[0045] The test results above show that the high-rigidity, high-output humanoid robot linear joint module of this invention has high load capacity, high precision, high stability and strong impact resistance, fully meeting the usage requirements of humanoid robots, and has significant progress and practicality compared with the existing technology.

[0046] Although embodiments of the present invention have been shown and described above, it is understood that these embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions, and alterations to the above embodiments within the scope of the present invention without departing from its principles and spirit. The scope of protection of the present invention is defined by the claims and their equivalents.

Claims

1. A high-rigidity, high-output humanoid robot linear joint module, characterized in that, include: The housing assembly includes a housing, a front cover, a rear cover, and a bearing housing, which are detachably connected to form a closed housing. The drive transmission mechanism includes a reverse planetary roller screw and a frameless torque motor sleeved on the outside of its nut; The bearing support system includes a pair of angular contact ball bearings arranged back to back and a deep groove ball bearing, which are respectively installed on opposite sides of the reverse planetary roller screw and are both assembled in the bearing housing. The anti-rotation limiting component includes a copper sleeve fitted on the lead screw of the reverse planetary roller screw, and the copper sleeve is provided with a limiting hole that matches the flat position on the lead screw. The position detection component includes a magnetic ring fixed on a mounting base and an encoder PCB board disposed opposite to the magnetic ring. The mounting base is fixed to the end of the reverse planetary roller screw. The control component includes a motor drive control board, which includes a control board and a power board, and is mounted on the bearing housing; The spherical bearing assembly includes two spherical bearings, which are respectively mounted on the rear cover plate and the screw extension end of the reverse planetary roller screw.

2. The linear joint module according to claim 1, characterized in that: The reverse planetary roller screw includes a screw body, a nut, and a plurality of rollers distributed between the two. The contact surfaces of the rollers with the screw body and the nut are in line contact.

3. The linear joint module according to claim 1, characterized in that: The stator of the frameless torque motor is fixed inside the housing, and its rotor is sleeved and fixed to the outside of the nut of the reverse planetary roller screw. The stator and rotor are arranged coaxially.

4. The linear joint module according to claim 1, characterized in that: It also includes a lead screw limit rod, which is sleeved on the lead screw of the reverse planetary roller lead screw and passes through the limit hole of the copper sleeve, with one end abutting against the lead screw body.

5. The linear joint module according to claim 1, characterized in that: The mounting base is fixed to the end of the reverse planetary roller screw by a set screw, and the mating part between the mounting base and the screw is provided with a stepped structure for axial positioning.

6. The linear joint module according to claim 1, characterized in that: The encoder PCB board is fixed to the bearing seat by a connector, and the distance between the encoder PCB board and the magnetic ring is adjustable.

7. The linear joint module according to claim 1, characterized in that: The motor drive control boards are arranged in a stacked manner and fixed to the bearing seat by support members.

8. The linear joint module according to claim 1, characterized in that: The pair of back-to-back angular contact ball bearings and the deep groove ball bearing are respectively pre-tightened and fixed in the bearing housing by locking components.

9. The linear joint module according to claim 1, characterized in that: The spherical bearing is a self-lubricating spherical bearing, and its inner ring is clearance-fitted with the mating parts.

10. The linear joint module according to claim 1, characterized in that: The connecting surfaces of the outer shell, front cover, bearing seat and rear cover are fitted with high precision, and the overall shell maintains coaxiality.

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