High-integration degree mechanical arm joint module

Abstract

The application relates to the technical field of mechanical arms, in particular to a high-integration-degree mechanical arm joint module which comprises a control unit, a coding unit, a core driving unit, a speed reduction unit, a bearing unit, a torque feedback unit, a crankshaft and a shell assembly; the bearing unit comprises a bearing inner ring, a bearing outer ring, steel balls and a sealing ring which are coaxially arranged, the bearing inner ring is provided with an outer groove matched with the steel balls on an outer wall, and the bearing outer ring is provided with an inner groove corresponding to the outer groove on an inner wall; the bearing inner ring is provided with an inner ring clamping groove for clamping the sealing ring at a position close to an end portion, and the bearing outer ring is provided with an outer ring clamping groove corresponding to the inner ring clamping groove at a position close to an end portion. The application has the effects of realizing the synergistic optimization of high torque density and low friction loss in a limited space, reducing the volume of a sealing structure and improving the integration degree of the module.

Description

Technical Field

[0001] This application relates to the technical field of robotic arms, and in particular to a highly integrated robotic arm joint module. Background Technology

[0002] Robotic arm joint modules are core motion units in industrial robots, special-operation equipment, and other fields. The core function of the joint module is to achieve complex motion control between adjacent links through high-precision, high-torque output.

[0003] In related technologies, joint modules typically consist of a drive unit (servo motor), a transmission unit (reducer or planetary gearbox), a support unit (bearing), and a sealing unit. They must meet stringent requirements such as high torque density, low friction loss, and dynamic response within a limited space to enable the robotic arm to perform load-bearing and precision movements in scenarios such as handling, assembly, and precision machining. The sealing structure of joint modules generally employs conventional skeleton oil seals to isolate the interface between the rotating shaft and the bearing housing / shell, and a lip seal structure to prevent grease from leaking out from the mating gap between the shaft and the shell.

[0004] Regarding the aforementioned technologies, although skeleton oil seals can achieve basic leak-proof functions, their overall thickness usually exceeds 5mm. During installation, an additional 3-5mm buffer gap needs to be reserved, which significantly reduces the layout space of the transmission unit or drive unit. This forces designers to use larger size reducers or higher power motors to compensate for torque loss, creating a vicious cycle of "volume-performance". On the other hand, the sliding friction between the rubber lip and the rotating shaft will consume additional system torque. Utility Model Content

[0005] In order to achieve synergistic optimization of high torque density and low friction loss within a limited space, reduce the volume of the sealing structure, and improve the module integration, this application provides a highly integrated robotic arm joint module.

[0006] The highly integrated robotic arm joint module provided in this application adopts the following technical solution: A highly integrated robotic arm joint module includes a control unit, an encoding unit, a core drive unit, a reduction unit, a bearing unit, a torque feedback unit, a crankshaft for linkage of the core drive unit, the reduction unit, and the bearing unit, and an outer housing assembly that provides installation space for each unit, arranged in sequence. The bearing unit includes a bearing inner ring and a bearing outer ring arranged coaxially, a plurality of steel balls that are rolled between the bearing inner ring and the bearing outer ring, and a sealing ring for sealing the bearing inner and outer rings. The bearing inner ring has an outer groove on its outer wall that mates with the steel balls, and the bearing outer ring has an inner groove on its inner wall that corresponds to the outer groove. The inner ring of the bearing has an inner ring groove near its end for the sealing ring to be inserted, and the outer ring of the bearing has an outer ring groove near its end that corresponds to the inner ring groove.

[0007] By adopting the above technical solution, the bearing unit of the joint module abandons the traditional bulky skeleton oil seal, integrating the sealing structure into the inner and outer rings of the bearing. This integrated sealing component reduces the installation clearance and buffer structure required by traditional oil seals, solving the problems of large volume, high friction loss, and limited module integration associated with existing sealing structures. The dual-bearing collaborative sealing mechanism sets sealing structures at both ends of the joint module's bearings. Precision-machined grooves embed the sealing rings into the inner and outer rings of the bearings, creating a bidirectional labyrinthine sealing path within the module system, blocking lubricant leakage. Simultaneously, it reduces axial space requirements, freeing up space for a compact layout of the drive and reduction units, balancing sealing reliability and lightweight requirements. This overcomes the "volume-performance" contradiction of traditional skeleton oil seals in precision joint modules, providing a foundation for the high integration and high performance development of industrial robots and special equipment.

[0008] Furthermore, the sealing ring includes a sealing ring portion for sealing the inner and outer rings of the bearing, an inner retaining ring portion for engaging with the inner ring retaining groove, and an outer retaining ring portion for engaging with the outer ring retaining groove. The outer retaining ring portion is integrally connected along the outer diameter direction of the sealing ring portion and is arranged perpendicular to the sealing ring portion. The outer retaining ring is circumferentially arranged on the outer wall and integrally connected with a retaining protrusion ring. The outer ring of the bearing is connected to the outer ring retaining groove and has an internal retaining ring groove for the retaining protrusion ring to be engaged.

[0009] By adopting the above technical solution, the sealing ring uses an integrated composite structure. The outer retaining ring extends vertically along the outer diameter of the sealing ring and is integrally connected to the retaining protrusion. The retaining protrusion and the inner retaining ring groove of the bearing outer ring form a mechanical interlock, preventing the sealing ring from falling off under high vibration conditions. The L-shaped cross-section formed by the sealing ring and the inner and outer retaining rings generates radial compressive stress after being inserted into the retaining groove, forming an adaptive elastic preload. This not only compensates for the difference in thermal expansion of the bearing, but also significantly increases the resistance to lubricating oil leakage through the labyrinthine sealing path with two 90° turns. The overall structure achieves rapid positioning through the guiding action of the retaining protrusion and the inner retaining ring groove, and also improves the impact resistance through the shear stress resistance of the composite structure, ensuring that the sealing ring maintains a stable fit during long-term use. The integrated design of the sealing ring and the bearing compresses the axial space to accommodate the compact layout of the drive unit and the reduction unit, balancing the requirements of sealing reliability and lightweight design, and providing sealing protection for the module.

[0010] Furthermore, the inner retaining ring portion is provided with a U-shaped deformation groove in the circumferential direction for elastic deformation.

[0011] By adopting the above technical solution, a U-shaped deformation groove is circumferentially provided on the inner retaining ring. This groove structure guides the inner retaining ring to undergo controllable radial elastic deformation during assembly, reducing the frictional resistance during assembly with the bearing inner ring groove. The deformation energy storage characteristic enhances the seal's ability to compensate for bearing thermal expansion. When the bearing experiences dimensional fluctuations due to temperature changes, the elastic deformation of the U-shaped groove automatically adjusts the sealing gap, avoiding stress concentration problems caused by traditional rigid clamping and maintaining stable sealing pressure. Through a deformation energy storage and release mechanism, the structure forms adaptive sealing compensation under dynamic operating conditions, mitigating the impact damage to the sealing interface from high-frequency vibrations. The deformation restoring force enhances the fit between the seal and the groove, providing a seal that combines flexibility and stability for high-precision bearing units.

[0012] Furthermore, the sealing ring has an annular liner inside for providing rigid support. The annular liner includes a first support ring embedded in the sealing ring portion and a second support ring embedded in the outer retaining ring portion and perpendicular to and integrally connected with the first support ring.

[0013] By adopting the above technical solution, the first support ring is embedded in the sealing ring to form a radially rigid skeleton, which can suppress the radial expansion deformation of the sealing ring under high pressure conditions and avoid the delamination of the sealing interface caused by excessive deformation of traditional soft sealing materials. The second support ring is vertically embedded in the outer retaining ring to form an axial support beam, which forms a triangular stress distribution structure with the bearing outer ring groove, decomposing the axial impact load into a radial component force, significantly reducing the risk of fatigue damage to the sealing ring under high-frequency vibration of the robot joint. The L-shaped orthogonal layout of the two support rings forms a self-reinforcing grid structure inside the sealing ring through the material mechanics coupling effect, improving the overall crush resistance of the sealing assembly. Through the rigid skeleton and the elastic sealing body complementing each other, the sealing interface is maintained in tight contact under extreme conditions.

[0014] Furthermore, the reduction unit includes a pin tooth housing installed within the housing assembly, and a first cycloidal wheel and a second cycloidal wheel arranged adjacent to each other within the pin tooth housing for cooperating with the crankshaft. The crankshaft has a first eccentric convex ring on its outer peripheral wall for cooperating with the first cycloidal wheel and a second eccentric convex ring for cooperating with the second cycloidal wheel. The first eccentric convex ring and the second eccentric convex ring are arranged adjacent to each other and are integrally connected to the crankshaft.

[0015] By adopting the above technical solution, the first eccentric cam ring and the second eccentric cam ring arranged adjacent to each other on the outer periphery of the crankshaft form a continuous eccentric trajectory through an integrated molding process, forming a two-stage planetary transmission chain with the first cycloidal wheel and the second cycloidal wheel, reducing the axial space occupation required by the traditional multi-stage eccentric gear train, and improving the reduction ratio accuracy through the superposition effect of eccentricity.

[0016] Furthermore, a plurality of steel balls are arranged circumferentially between the first cycloidal wheel and the first eccentric convex ring. The first cycloidal wheel has an inner groove on its inner wall for the steel balls to be inserted. The first eccentric convex ring has an outer groove on its outer wall that corresponds to the inner groove of the cycloidal wheel.

[0017] By adopting the above technical solution, the circumferential constraint channel formed by the inner groove of the cycloidal wheel and the outer groove of the convex ring ensures that the steel balls maintain rolling contact, transforming traditional sliding friction into rolling friction to reduce energy loss. The radial limiting effect of the groove structure on the steel balls controls the phenomenon of contact stress concentration, avoiding material fatigue caused by local overload. At the same time, the continuous rolling path of the steel balls in the groove forms a dynamic pressure equilibrium distribution, suppressing the transmission of high-frequency vibration to the transmission system. Through the cooperative constraint of the groove and rail and the mediating effect of the rolling medium, the motion smoothness and impact resistance of the reduction unit are improved while ensuring power transmission efficiency, providing a reliability guarantee for high-precision cycloidal transmission systems.

[0018] Furthermore, a ball retainer is provided between the first cycloidal wheel and the first eccentric convex ring. The ball retainer is provided with ball-and-socket grooves at equal intervals for each ball to be inserted and rolled together. The inner groove of the cycloidal wheel, the outer groove of the convex ring and the ball-and-socket grooves together form a chamber for the steel balls to roll.

[0019] By adopting the above technical solution, during the periodic rotation of the crankshaft and eccentric ring, the steel balls between the cycloidal wheel and the eccentric ring experience intermittent contact stress fluctuations due to changes in eccentricity. The ball-and-socket grooves of the ball cage form a rigid support network through preset geometric constraints, maintaining the rolling path accuracy of the steel balls when loaded. In the unloaded stage, the groove structure radially positions the steel balls, avoiding steel ball accumulation or idle stroke caused by inertial displacement. Through the elastic support of the ball cage, a dynamic pressure compensation layer is formed in the meshing gap between the eccentric ring and the cycloidal wheel. When the eccentric ring experiences a sudden change in load, causing some steel balls to lose contact, the cage applies a preload force to the steel balls through the micro-elastic deformation of the groove wall, maintaining the continuous contact state of the transmission pair and eliminating the impact vibration that may be caused by traditional free rolling. The ball sockets of the ball cage are evenly distributed, which disperses the peak force of the ball into multiple levels of buffer. Combined with the damping effect of the lubricating medium in the chamber, it reduces the risk of ball fatigue and spalling caused by alternating loads, providing shock-resistant and long-life transmission protection for high dynamic cycloidal deceleration systems.

[0020] Furthermore, the core drive unit includes a stator fixedly connected to the outer housing assembly and a rotor assembly disposed outside the crankshaft and between the stator. The rotor assembly includes an adapter ring sleeved and fixedly connected to the outside of the crankshaft, a magnet frame sleeved and fixedly connected to the outside of the adapter ring, and a plurality of magnet plates for cooperating with the stator. Each magnet plate is circumferentially disposed outside the magnet frame and is arranged along the length direction of the crankshaft.

[0021] By adopting the above technical solution, the modular assembly structure of the adapter ring and the magnet frame efficiently transfers the crankshaft's rotational kinetic energy to the permanent magnet magnetic field system. The circumferentially distributed annular magnets are continuously arranged axially to form a sinusoidal magnetic field gradient, eliminating the cogging effect of traditional centralized magnetic pole layouts. The alternating distribution of magnetic poles enhances the uniformity of air gap magnetic flux density, significantly improving the efficiency of electro-mechanical energy conversion. The axial arrangement of the magnets along the crankshaft's length effectively utilizes spatial dimensions, increasing the effective magnetic circuit cross-sectional area while reducing magnetic reluctance loss. Combined with the distributed winding design of the stator windings, this forms multi-pole pair magnetic field coupling, achieving low-speed, high-torque output characteristics.

[0022] Furthermore, the length of each of the magnetic steel sheets is the same as the length of the magnetic steel frame, the length of the magnetic steel frame is greater than the length of the adapter ring, and the adapter ring is located at the middle position of the magnetic steel frame.

[0023] By adopting the above technical solution, the axial extension of the magnetic steel sheet and the magnetic steel frame of equal length ensures the continuity of the magnetic pole distribution, eliminating the magnetic field distortion caused by traditional segmented magnetic pole splicing. Simultaneously, the end extension of the magnetic steel frame beyond the adapter ring forms a magnetic flux buffer, effectively suppressing end leakage magnetic effects through reluctance gradient adjustment. The geometric constraint of the centrally located adapter ring evenly distributes the load on the magnetic steel frame to the magnetic pole regions on both sides, avoiding fatigue cracks caused by stress concentration on one side of the magnet. Combined with the equal-length matching characteristics of the magnetic steel sheet and the magnetic steel frame, a symmetrical magnetic circuit coupling structure is formed. The synergistic optimization of the magnetic pole distribution and mechanical structure improves the utilization rate of permanent magnet materials while reducing the impact of magnetic field harmonics on motor control accuracy, providing a stable electromagnetic foundation for high-power-density drive systems.

[0024] Furthermore, the housing assembly includes a first housing for mounting the core drive unit and the deceleration unit, a second housing for mounting the encoding unit and the control unit, and a rear cover for cooperating with the second housing; The first housing has a first mounting inner plate circumferentially arranged and fixedly connected to the inner wall on the side near the bearing unit, and the second housing has a second mounting inner plate for insertion into the first housing on the side away from the rear cover. The outer wall of the crankshaft, the inner wall of the magnet frame, and the end of the adapter ring near the reduction unit together form a first mounting chamber into which the first mounting inner plate extends. The outer wall of the crankshaft, the inner wall of the magnet frame, and the end of the adapter ring near the encoding unit together form a second mounting chamber into which the second mounting inner plate extends.

[0025] By adopting the above technical solution, the adapter ring is centrally positioned, allowing the extended sections at both ends of the magnet frame to form mounting chambers, providing a mounting base for the housing components. Matching the chambers with the housing eliminates redundant axial spacing. The dual-chamber structure integrates the drive unit and control unit housings within the extended sections of the magnet frame, forming a stacked layout along the axial direction. The spatial structure formed by the extended sections at the ends of the magnet frame allows the housings of the encoding unit and control unit to be nested and installed on both sides of the magnet frame, while maintaining minimum electrical safety distance between each unit, resolving the conflict between electromagnetic compatibility and spatial layout in high-power-density drive systems.

[0026] In summary, this application includes at least one of the following beneficial technical effects: 1. By embedding the sealing ring into the inner and outer ring bodies of the bearing, a bidirectional sealing path is constructed, eliminating the volume occupation of traditional skeleton oil seals and forming dynamic pressure compensation. The L-shaped composite structure of the sealing ring and the snap-fit ​​convex ring enhance vibration resistance through mechanical interlocking, and the U-shaped deformation groove achieves adaptive thermal expansion compensation. This breaks through the axial space limitations of traditional sealing structures, ensuring no lubricating oil leakage while freeing up space for the compact arrangement of the drive unit and reduction unit, reducing the overall axial length of the module; 2. The double cycloidal wheel and the crankshaft eccentric cam ring form a two-stage planetary reduction chain. The inner groove of the cycloidal wheel and the outer groove of the cam ring precisely fit with the steel balls, converting sliding friction into rolling friction and reducing energy loss. The dynamic pressure compensation mechanism of the steel ball cage maintains a uniform distribution of contact stress in the steel balls when the eccentricity changes, keeping the reduction ratio accuracy error within a very small range. At the same time, the elastic support structure reduces the vibration amplitude, achieving a synergistic optimization of high torque density and low noise. 3. The first and second housings are arranged separately, with the drive unit, reduction unit, and control unit stacked and integrated along the axial direction. The cavity formed by the extension section at the end of the magnet frame allows the encoding unit and control unit housings to be nested together, improving electromagnetic shielding effectiveness. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the overall structure of a highly integrated robotic arm joint module according to an embodiment of this application.

[0028] Figure 2 This is a schematic cross-sectional view of a highly integrated robotic arm joint module according to an embodiment of this application. Figure 1 .

[0029] Figure 3 This is an exploded view of the structure of the outer shell assembly, control unit, and coding unit in the embodiments of this application.

[0030] Figure 4 This is an exploded view of the first housing, core drive unit, and second housing in an embodiment of this application. Figure 1 .

[0031] Figure 5 This is an exploded view of the first housing, core drive unit, and second housing in an embodiment of this application. Figure 2 .

[0032] Figure 6 This is an exploded view of the crankshaft and reduction unit in the embodiments of this application.

[0033] Figure 7 This is a cross-sectional structural diagram of the crankshaft and bearing unit in an embodiment of this application.

[0034] Figure 8 This is a cross-sectional structural diagram of the bearing unit in an embodiment of this application.

[0035] Figure 9 This is a cross-sectional schematic diagram of the sealing ring in an embodiment of this application.

[0036] Figure 10 This is an exploded view of the structure of the torque feedback unit and other units of the module in the embodiments of this application.

[0037] Figure 11 This is a schematic cross-sectional view of a highly integrated robotic arm joint module according to an embodiment of this application. Figure 2 .

[0038] Explanation of reference numerals in the attached drawings: 1. Control unit; 11. Driver board; 12. Encoder board; 2. Encoding unit; 21. High-speed encoder; 22. Output encoder; 3. Core drive unit; 31. Stator; 32. Rotor assembly; 321. Adapter ring; 3211. First mounting chamber; 3212. Second mounting chamber; 322. Magnet frame; 323. Magnet sheet; 4. Reduction unit; 41. Needle tooth housing; 42. First cycloidal wheel; 421. Cycloidal wheel inner groove; 43. Second cycloidal wheel; 5. Bearing unit; 51. Bearing inner ring; 511. Outer groove; 512. Inner ring slot; 52. Bearing outer ring; 521. Inner groove; 522. Outer ring slot; 523. Snap ring groove; 53. Steel ball; 54. Sealing ring; 541. Sealing ring portion; 542. Inner retaining ring portion; 5421. U-shaped deformation groove; 543. Outer retaining ring portion; 5431. Snap-fitting protrusion ring; 544. Annular liner; 5441. First support ring; 5442. Second support ring; 6. Torque feedback unit; 61. Sensor body; 611. Positioning pin; 62. Mounting housing; 621. Positioning groove; 622. Circumferential angle mark; 7. Crankshaft; 71. First eccentric protrusion ring; 711. Outer groove of protrusion ring; 72. Second eccentric protrusion ring; 73. Steel ball retainer; 731. Ball socket groove; 8. Housing assembly; 81. First housing; 811. First mounting inner plate; 82. Second housing; 821. Second mounting inner plate; 83. Rear cover. Detailed Implementation

[0039] To make the purpose, technical solution, and advantages of this application clearer, the following description is provided in conjunction with the appendix. Figure 1-11 The present application will be further described in detail with reference to the embodiments.

[0040] This application discloses a highly integrated robotic arm joint module. (Refer to...) Figure 1 and Figure 2 The highly integrated robotic arm joint module includes a control unit 1, an encoding unit 2, a core drive unit 3, a reduction unit 4, a bearing unit 5, a torque feedback unit 6, a crankshaft 7, and a housing assembly 8. The crankshaft 7 is used to link the encoding unit 2, the core drive unit 3, the reduction unit 4, and the bearing unit 5, while the housing assembly 8 provides installation space for each unit of the module.

[0041] Reference Figure 2 and Figure 3 The outer casing assembly 8 includes a first casing 81, a second casing 82, and a rear cover 83. The first casing 81 is used to install the core drive unit 3 and the reduction unit 4. The second casing 82 is used to install the encoding unit 2 and the control unit 1. The rear cover 83 is interlocked and fixedly connected with the second casing 82 to enclose the encoding unit 2 and the control unit 1.

[0042] Control unit 1 includes a driver board 11 and an encoder board 12 arranged adjacent to each other for electrical connection. Encoding unit 2 includes a high-speed encoder 21 and an output encoder 22 arranged coaxially. The high-speed encoder 21 is adapted to the crankshaft 7 and is used to monitor the status of the core drive unit 3 (motor). The output encoder 22 is connected to the output end via a screw coaxially passing through the motor crankshaft 7, thereby monitoring the status of the reduction unit 4 located near the output end.

[0043] Reference Figure 4 and Figure 5 In this embodiment, the core drive unit 3 is preferably a frameless torque motor capable of providing high torque. The core drive unit 3 includes a stator 31 fixedly connected to the first housing 81 and a rotor assembly 32 disposed between the crankshaft 7 and the stator 31. The rotor assembly 32 includes an adapter ring 321 sleeved and fixedly connected to the outside of the crankshaft 7, a magnet frame 322 sleeved and fixedly connected to the outside of the adapter ring 321, and a plurality of magnet plates 323 for cooperating with the stator 31. Each magnet plate 323 is circumferentially arranged around the outside of the magnet frame 322 and is arranged along the length direction of the crankshaft 7.

[0044] The first housing 81 has a first mounting inner plate 811 circumferentially arranged and fixedly connected to the inner wall of the first housing 81 near the bearing unit 5, and the second housing 82 has a second mounting inner plate 821 integrally connected to the side away from the rear cover 83 for inserting into the first housing 81.

[0045] In this embodiment, the length of each magnet 323 is the same as the length of the magnet frame 322, and the length of the magnet frame 322 is greater than the length of the adapter ring 321. The adapter ring 321 is located in the middle of the magnet frame 322. The axial extension of the magnet 323 and the magnet frame 322 of equal length ensures the continuity of the magnetic pole distribution and eliminates the magnetic field distortion caused by the traditional segmented magnetic pole splicing. At the same time, the end extension of the magnet frame 322 beyond the adapter ring 321 forms a magnetic flux buffer, which effectively suppresses the end leakage magnetic effect through magnetic reluctance gradient adjustment. The geometric constraint of the centrally located adapter ring 321 evenly distributes the stress load of the magnet frame 322 to the magnetic pole regions on both sides, avoiding fatigue cracks caused by stress concentration on one side of the magnet. Combined with the equal length matching characteristics of the magnet 323 and the magnet frame 322, a symmetrical magnetic circuit coupling structure is formed. The synergistic optimization of magnetic pole distribution and mechanical structure improves the utilization rate of permanent magnet materials while reducing the impact of magnetic field harmonics on motor control accuracy, providing a stable electromagnetic foundation for high power density drive systems.

[0046] The outer wall of the crankshaft 7, the inner wall of the magnet frame 322, and the end of the adapter ring 321 near the reduction unit 4 together constitute the first mounting chamber 3211 into which the first mounting inner plate 811 extends. The outer wall of the crankshaft 7, the inner wall of the magnet frame 322, and the end of the adapter ring 321 near the encoding unit 2 together constitute the second mounting chamber 3212 into which the second mounting inner plate 821 extends. The first mounting chamber 3211 and the second mounting chamber 3212 are located at opposite ends of the adapter ring 321.

[0047] The adapter ring 321 is centrally located, allowing the extended sections at both ends of the magnet frame 322 to form mounting chambers, providing a mounting base for the housing assembly 8. By matching the chambers with the housing, redundant axial spacing is eliminated. The dual-chamber structure integrates the housings of the drive unit and control unit 1 within the extended sections of the magnet frame 322, forming a stacked layout along the axial direction. The spatial structure formed by the extended sections at the ends of the magnet frame 322 allows the housings of the encoding unit 2 and control unit 1 to be nested and installed on both sides of the magnet frame 322, while maintaining a minimum electrical safety distance between each unit, resolving the conflict between electromagnetic compatibility and spatial layout in high-power-density drive systems.

[0048] Reference Figure 6 and Figure 7The reduction unit 4 includes a pin tooth housing 41 installed within the first housing 81, and a first cycloidal wheel 42 and a second cycloidal wheel 43 arranged adjacent to and meshing within the pin tooth housing 41. The crankshaft 7 has a first eccentric convex ring 71 on its outer peripheral wall for engaging with the first cycloidal wheel 42 and a second eccentric convex ring 72 for engaging with the second cycloidal wheel 43. The first eccentric convex ring 71 and the second eccentric convex ring 72 are arranged adjacent to each other and are integrally connected to the crankshaft 7. The first eccentric convex ring 71 and the second eccentric convex ring 72 arranged adjacent to each other on the outer peripheral wall of the crankshaft 7 form a continuous eccentric trajectory through an integrated molding process, forming a two-stage planetary transmission chain with the first cycloidal wheel 42 and the second cycloidal wheel 43. This reduces the axial space required by traditional multi-stage eccentric gear trains and improves the reduction ratio accuracy through the superposition effect of eccentricity.

[0049] Multiple steel balls 53 (not shown in the figure) are circumferentially arranged between the first cycloidal wheel 42 and the first eccentric ring 71. The first cycloidal wheel 42 has an inner groove 421 on its inner wall for the steel balls 53 to be inserted. The first eccentric ring 71 has an outer groove 711 on its outer wall corresponding to the inner groove 421. A steel ball 53 retainer is provided between the first cycloidal wheel 42 and the first eccentric ring 71. The steel ball 53 retainer has ball-and-socket grooves 731 at equal intervals for each steel ball 53 to be inserted and rolled together. The inner groove 421, the outer groove 711, and the ball-and-socket grooves 731 together form a chamber for the steel balls 53 to roll. The second cycloidal wheel 43 and the second eccentric ring 72 are also arranged with steel balls 53 and a steel ball 53 retainer, in the same manner as the first cycloidal wheel 42 and the first eccentric ring 71.

[0050] During the periodic rotation of crankshaft 7 and eccentric ring, the steel balls 53 between the cycloidal wheel and eccentric ring experience intermittent contact stress fluctuations due to changes in eccentricity. The ball-and-socket grooves 731 of the steel ball 53 cage form a rigid support network through preset geometric constraints. This maintains the rolling path accuracy of the steel balls 53 when they are under load, and radially positions them through the groove structure during the unloaded phase, preventing accumulation or idle strokes caused by inertial displacement. The elastic support of the steel ball 53 cage creates a dynamic pressure compensation layer in the meshing gap between the eccentric ring and the cycloidal wheel. When a sudden change in load causes some steel balls 53 to lose contact, the cage applies a preload force to the steel balls 53 through the micro-elastic deformation of the groove wall, maintaining continuous contact between the transmission pair and eliminating the impact vibrations that might occur with traditional free rolling. The ball sockets 731 of the steel ball 53 cage are evenly distributed, which disperses the peak force of the steel ball 53 into multi-level buffers. Combined with the damping effect of the lubricating medium in the chamber, it reduces the risk of fatigue spalling of the steel ball 53 caused by alternating loads, and provides shock-resistant and long-life transmission protection for the high dynamic cycloidal deceleration system.

[0051] Reference Figure 7 and Figure 8The bearing unit 5 includes a bearing inner ring 51 and a bearing outer ring 52 arranged coaxially, a plurality of steel balls 53 rollingly connected between the bearing inner ring 51 and the bearing outer ring 52, and a sealing ring 54 for sealing the bearing inner and outer rings.

[0052] The bearing unit 5 of the joint module abandons the traditional bulky skeleton oil seal, integrating the sealing structure into the inner ring 51 and outer ring body of the bearing. This integrated sealing component reduces the installation clearance and buffer structure required by traditional oil seals, solving the problems of large volume, high friction loss, and limited module integration of existing sealing structures. A two-end bearing collaborative sealing mechanism is implemented, with sealing structures set at both ends of the joint module's bearings. Precision-machined grooves embed the sealing ring 54 into the inner and outer rings of the bearings, creating a sealing path within the module system and blocking lubricant leakage. Simultaneously, it reduces axial space requirements, freeing up space for a compact layout of the drive unit and reduction unit 4. This balances sealing reliability with lightweight requirements, overcoming the "volume-performance" contradiction of traditional skeleton oil seals in precision joint modules, and providing a foundation for the high integration and high performance development of industrial robots and special equipment.

[0053] The inner ring 51 of the bearing has an outer groove 511 on its outer wall circumferentially to mate with the steel ball 53, and the outer ring 52 of the bearing has an inner groove 521 on its inner wall circumferentially corresponding to the outer groove 511. The inner ring 51 of the bearing has an inner ring groove 512 near its end for the sealing ring 54 to be inserted, and the outer ring 52 of the bearing has an outer ring groove 522 near its end corresponding to the inner ring groove 512.

[0054] Reference Figure 8 and Figure 9 The sealing ring 54 includes a sealing ring portion 541 for sealing the inner and outer rings of the bearing, an inner retaining ring portion 542 for engaging with the inner ring retaining groove 512, and an outer retaining ring portion 543 for engaging with the outer ring retaining groove 522. The outer retaining ring portion 543 is integrally connected along the outer diameter direction of the sealing ring portion 541 and is perpendicular to the sealing ring portion 541. The outer retaining ring portion 543 is circumferentially arranged on its outer wall and integrally connected with a retaining protrusion ring 5431. The outer ring 52 of the bearing has an internal retaining ring groove 523 in the outer ring retaining groove 522 for the retaining protrusion ring 5431 to engage. The inner retaining ring portion 542 has a U-shaped deformation groove 5421 circumferentially formed for elastic deformation.

[0055] The sealing ring 54 adopts an integrated composite structure. The outer retaining ring portion 543 extends vertically along the outer diameter direction of the sealing ring portion 541 and is integrally connected to the retaining protrusion ring 5431. The retaining protrusion ring 5431 and the inner retaining ring groove 523 of the bearing outer ring 52 form a mechanical interlock to prevent the sealing ring 54 from falling off under high vibration conditions. The L-shaped cross-section formed by the sealing ring portion 541 and the inner and outer retaining ring portions 543 generates radial compressive stress after being inserted into the groove, forming an adaptive elastic preload. This not only compensates for the difference in thermal expansion of the bearing, but also significantly increases the resistance to lubricating oil leakage through the labyrinthine sealing path with two 90° turns. The overall structure achieves rapid positioning through the guiding action of the retaining protrusion ring 5431 and the inner retaining ring groove 523, and also improves the impact resistance through the shear stress resistance of the composite structure, so that the sealing ring 54 maintains a stable fit during long-term use. The integrated design of the sealing ring 54 and the bearing compresses the axial space to adapt to the compact layout of the drive unit and the reduction unit 4, balancing the requirements of sealing reliability and lightweight, and providing sealing protection for the module.

[0056] The inner retaining ring 542 is circumferentially provided with a U-shaped deformation groove 5421. This groove structure guides the inner retaining ring 542 to undergo controllable radial elastic deformation during assembly, reducing the frictional resistance during assembly with the bearing inner ring 51 groove. The deformation energy storage characteristic enhances the sealing ring 54's ability to compensate for bearing thermal expansion. When the bearing experiences dimensional fluctuations due to temperature changes, the elastic deformation of the U-shaped groove automatically adjusts the sealing gap, avoiding stress concentration problems caused by traditional rigid clamping and maintaining stable sealing pressure. Through a deformation energy storage and release mechanism, the structure forms adaptive sealing compensation under dynamic operating conditions, mitigating the impact damage to the sealing interface from high-frequency vibrations. The deformation restoring force enhances the fit between the sealing ring 54 and the groove, providing a seal that combines flexibility and stability for the high-precision bearing unit 5.

[0057] The sealing ring 54 has an annular liner 544 inside for providing rigid support. The annular liner 544 includes a first support ring 5441 embedded in the sealing ring portion 541 and a second support ring 5442 embedded in the outer retaining ring portion 543 and perpendicular to and integrally connected with the first support ring 5441.

[0058] The first support ring 5441 is embedded in the sealing ring portion 541 to form a radially rigid skeleton, which can suppress the radial expansion deformation of the sealing ring 54 under high pressure conditions and avoid the delamination of the sealing interface caused by excessive deformation of traditional soft sealing materials. The second support ring 5442 is vertically embedded in the outer retaining ring portion 543 to form an axial support beam, which forms a triangular stress distribution structure with the bearing outer ring 52 groove, decomposing the axial impact load into a radial component force, significantly reducing the risk of fatigue damage to the sealing ring 54 under high-frequency vibration of the robot joint. The L-shaped orthogonal layout of the two support rings forms a self-reinforcing grid structure inside the sealing ring 54 through the material mechanics coupling effect, improving the overall crush resistance of the sealing assembly. Through the rigid skeleton and the elastic sealing body complementing each other, the sealing interface is maintained in tight contact under extreme conditions.

[0059] Reference Figure 10 and Figure 11 The torque feedback unit 6 is preferably a high-precision torque sensor, comprising a sensor body 61 and a mounting housing 62. A positioning pin 611 is vertically arranged and fixedly connected to the side wall of the sensor body 61. The mounting housing 62 has a positioning groove 621 on its inner peripheral wall for the positioning pin 611 to extend into. The positioning structure formed by the positioning pin 611 and the positioning groove 621 can prevent angle changes caused by accidental human intervention. In this embodiment, the circumferential angle of the positioning groove 621 is 180°, and the mounting housing 62 has a circumferential angle marking 622 on its outer peripheral wall that matches the circumferential angle.

[0060] In this embodiment, the mounting housing 62 is arranged adjacent to and detachably connected to the bearing unit 5. Removing the torque feedback unit 6 does not affect the overall function of the module. The end face of the bearing unit 5 can be quickly adapted to other systems after simple modification.

[0061] The implementation principle of a highly integrated robotic arm joint module in this application embodiment is as follows: through multi-unit collaborative optimization and structural innovation, high torque density, low friction loss, and high reliability are achieved within a limited space. The core drive unit 3 adopts a frameless torque motor. The rotor assembly 32 is integrated with the crankshaft 7 through a transition ring 321, a magnet frame 322, and axially continuously arranged magnet plates 323. The axial extension of the magnet plates 323 increases the effective magnetic circuit cross-sectional area, and combined with the stator 31 windings, a multi-pole logarithmic magnetic field coupling is formed, outputting low speed and high torque. The reduction unit 4, through the meshing of the eccentric convex ring of the crankshaft 7 with the first and second cycloidal wheels 43, and in conjunction with the cavity structure of the cycloidal wheel inner groove 421, the outer groove 711 of the convex ring, and the steel ball 53 retainer, converts sliding friction into rolling friction. Through the dynamic pressure compensation and elastic support of the steel ball 53 retainer, vibration is suppressed and transmission smoothness is improved. Bearing unit 5 abandons the traditional skeleton oil seal, integrating the sealing ring 54 into the inner and outer rings of the bearing. A sealing path is formed through an L-shaped composite structure, a snap-fit ​​protruding ring 5431, and a U-shaped deformation groove 5421, achieving adaptive thermal compensation and impact-resistant sealing while compressing axial space. The outer casing assembly 8, through the separate layout of the first and second housings 82, combined with the mounting inner plate and chamber structure, integrates the drive, deceleration, and control unit 1 axially, resolving the conflict between electromagnetic compatibility and spatial layout. The torque feedback unit 6, through the fixing structure of the positioning pin 611 and the positioning groove 621, achieves quick disassembly while retaining its function. Through structural synergy and innovation, each unit achieves the performance goals of high integration, high torque density, and low friction loss within a limited space.

[0062] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made to the structure, shape, and principle of this application should be covered within the scope of protection of this application. In the description of this embodiment, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" 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 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. Since the embodiments disclosed in this application can be set in different directions, these terms indicating direction are only for illustration and should not be regarded as limitations. For example, "upper" and "lower" are not necessarily limited to directions opposite to or consistent with the direction of gravity. In addition, features defined as "first" and "second" may explicitly or implicitly include one or more of these features.

Claims

1. A highly integrated robotic arm joint module, characterized in that: It includes a control unit (1), an encoding unit (2), a core drive unit (3), a reduction unit (4), a bearing unit (5), a torque feedback unit (6), a crankshaft (7), and an outer housing assembly (8) that provides installation space for each unit, arranged in sequence. The bearing unit (5) includes a bearing inner ring (51) and a bearing outer ring (52) arranged coaxially, a plurality of steel balls (53) rollingly connected between the bearing inner ring (51) and the bearing outer ring (52), and a sealing ring (54) for sealing the bearing inner and outer rings. The bearing inner ring (51) has an outer groove (511) on its outer wall that mates with the steel balls (53), and the bearing outer ring (52) has an inner groove (521) on its inner wall that corresponds to the outer groove (511). The bearing inner ring (51) has an inner ring groove (512) near the end for the sealing ring (54) to be inserted, and the bearing outer ring (52) has an outer ring groove (522) near the end corresponding to the inner ring groove (512).

2. The highly integrated robotic arm joint module according to claim 1, characterized in that: The sealing ring (54) includes a sealing ring portion (541) for sealing the inner and outer rings of the bearing, an inner retaining ring portion (542) for engaging with the inner ring retaining groove (512), and an outer retaining ring portion (543) for engaging with the outer ring retaining groove (522). The outer retaining ring portion (543) is integrally connected along the outer diameter direction of the sealing ring portion (541) and is arranged perpendicular to the sealing ring portion (541). The outer retaining ring portion (543) is circumferentially arranged on the outer wall and integrally connected with a retaining protrusion ring (5431). The bearing outer ring (52) is connected in the outer ring retaining groove (522) and has an internal retaining ring groove (523) for the retaining protrusion ring (5431) to be engaged.

3. The highly integrated robotic arm joint module according to claim 2, characterized in that: The inner retaining ring portion (542) is provided with a U-shaped deformation groove (5421) for elastic deformation.

4. The highly integrated robotic arm joint module according to claim 2, characterized in that: The sealing ring (54) has an annular liner (544) inside for providing rigid support. The annular liner (544) includes a first support ring (5441) embedded in the sealing ring portion (541) and a second support ring (5442) embedded in the outer retaining ring portion (543) and perpendicular to and integrally connected with the first support ring (5441).

5. A highly integrated robotic arm joint module according to claim 1, characterized in that: The reduction unit (4) includes a pin tooth housing (41) installed in the housing assembly (8) and a first cycloidal wheel (42) and a second cycloidal wheel (43) arranged adjacent to each other in the pin tooth housing (41) for cooperating with the crankshaft (7). The crankshaft (7) has a first eccentric convex ring (71) for cooperating with the first cycloidal wheel (42) and a second eccentric convex ring (72) for cooperating with the second cycloidal wheel (43) on its outer peripheral wall. The first eccentric convex ring (71) and the second eccentric convex ring (72) are arranged adjacent to each other and are integrally connected to the crankshaft (7).

6. A highly integrated robotic arm joint module according to claim 5, characterized in that: A plurality of steel balls (53) are arranged circumferentially between the first cycloidal wheel (42) and the first eccentric convex ring (71). The first cycloidal wheel (42) has an inner groove (421) on its inner wall for the steel balls (53) to be inserted. The first eccentric convex ring (71) has an outer groove (711) on its outer wall that corresponds to the inner groove (421) of the cycloidal wheel.

7. A highly integrated robotic arm joint module according to claim 6, characterized in that: A ball (53) holder is provided between the first cycloidal wheel (42) and the first eccentric convex ring (71). The ball (53) holder is provided with ball-and-socket grooves (731) spaced at equal intervals for each ball (53) to be inserted and rolled together. The inner groove (421) of the cycloidal wheel, the outer groove (711) of the convex ring and the ball-and-socket grooves (731) together form a chamber for the ball (53) to roll.

8. A highly integrated robotic arm joint module according to claim 1, characterized in that: The core drive unit (3) includes a stator (31) fixedly connected to the outer casing assembly (8) and a rotor assembly (32) disposed between the crankshaft (7) and the stator (31). The rotor assembly (32) includes a transition ring (321) sleeved and fixedly connected to the outside of the crankshaft (7), a magnet frame (322) sleeved and fixedly connected to the outside of the transition ring (321), and a plurality of magnet plates (323) for cooperating with the stator (31). Each magnet plate (323) is circumferentially disposed around the outside of the magnet frame (322) and is arranged along the length direction of the crankshaft (7).

9. A highly integrated robotic arm joint module according to claim 8, characterized in that: The length of each of the magnetic steel sheets (323) is the same as the length of the magnetic steel frame (322), the length of the magnetic steel frame (322) is greater than the length of the adapter ring (321), and the adapter ring (321) is located at the middle position of the magnetic steel frame (322).

10. A highly integrated robotic arm joint module according to claim 9, characterized in that: The outer casing assembly (8) includes a first housing (81) for mounting the core drive unit (3) and the deceleration unit (4), a second housing (82) for mounting the encoding unit (2) and the control unit (1), and a rear cover (83) for cooperating with the second housing (82); The first housing (81) has a first mounting inner plate (811) arranged circumferentially on the inner wall near the bearing unit (5) and fixedly connected thereto. The second housing (82) has a second mounting inner plate (821) for insertion into the first housing (81) on the side away from the rear cover (83). The outer wall of the crankshaft (7), the inner wall of the magnet frame (322), and the end of the adapter ring (321) near the reduction unit (4) together constitute a first mounting chamber (3211) into which the first mounting inner plate (811) extends. The outer wall of the crankshaft (7), the inner wall of the magnet frame (322), and the end of the adapter ring (321) near the encoding unit (2) together constitute a second mounting chamber (3212) into which the second mounting inner plate (821) extends.

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