Modular harmonic reducer for humanoid robot joints and assembly process thereof

Abstract

The present application relates to the technical field of harmonic reducer, and discloses a modular harmonic reducer for a humanoid robot joint and an assembling process thereof, which comprises a mounting shell, a reducer body, a base plate and a first limiting piece. The mounting shell has a receiving cavity for accommodating the reducer body, and a wall of the mounting shell is provided with an assembling hole penetrating through in the axial direction. The reducer body comprises a flexible gear, a rigid gear and a wave generator. The first limiting piece has an annular limiting boss for fixing an outer bearing. A motor shaft of an outer driving motor is connected with the wave generator of the reducer body through the bearing and the annular limiting boss. The reducer body is arranged in the mounting shell. The quick-release connecting piece penetrates through the assembling hole and connects the base plate to limit the reducer body between the mounting shell and the base plate. The base plate is arranged between the outer driving motor and the mounting shell.

Description

Technical Field

[0001] This invention relates to the field of harmonic reducer technology, and in particular discloses a modular harmonic reducer for humanoid robot joints and its assembly process. Background Technology

[0002] With the continuous development of humanoid robot technology, harmonic reducers, as key components of joint transmission, directly affect the robot's motion accuracy, stability, and service life. Traditional harmonic reducers suffer from problems in structural design, such as complex assembly, poor heat dissipation, and inaccurate torque monitoring, making it difficult to meet the requirements of humanoid robots for high joint integration, high reliability, and high response speed under complex working conditions. Furthermore, existing reducers also have shortcomings in vibration suppression and connection stability, leading to vibration and noise during robot operation and affecting its overall performance. Summary of the Invention

[0003] In order to overcome the shortcomings of existing technologies in terms of vibration suppression and connection stability, the present invention aims to provide a modular harmonic reducer for humanoid robot joints and its assembly process.

[0004] To achieve the above objectives, the present invention provides a modular harmonic reducer for a humanoid robot joint, comprising a mounting housing, a reducer body, a base plate, and a first limiting member; the mounting housing has a receiving cavity for accommodating the reducer body, and the wall of the mounting housing has an assembly hole extending through it in the axial direction; the reducer body includes a flexible wheel, a rigid wheel, and a wave generator; the first limiting member has an annular limiting boss for fixing an external bearing; the motor shaft of an external drive motor is connected to the wave generator of the reducer body via the bearing and the annular limiting boss; it also includes a quick-release connector, the reducer body is disposed within the mounting housing, the quick-release connector extends through the assembly hole and connects to the base plate to limit the reducer body between the mounting housing and the base plate, and the base plate is disposed between the external drive motor and the mounting housing.

[0005] Furthermore, the radial length of the annular limiting boss is 1.2-1.5 times the thickness of the bearing outer ring of the reducer body, and the annular limiting boss of the first limiting member forms an axial fitting clearance of 0.02-0.05mm with the bearing outer ring of the harmonic reducer.

[0006] Furthermore, the mounting housing is provided with a spiral cooling channel with a helix angle of 45°±5°. The cross-section of the cooling channel is circular and its spiral axis is parallel to the central axis of the mounting housing.

[0007] Furthermore, a detachable split liquid cooling module is added to the outer wall of the mounting housing. This module consists of an aluminum alloy shell and an internally arranged honeycomb microchannel. The inlet / outlet of the microchannel is connected to an external cooling circulation system via a quick-connect connector.

[0008] Furthermore, the surface of the spiral cooling channel inside the housing is coated with a silicon carbide thermally conductive coating with a thickness of 10-20 micrometers. An adaptive guide vane is provided at the end of the spiral channel. The guide vane is made of shape memory alloy. When the coolant flow rate in the channel is ≥1.5m / s, the guide vane automatically expands to a 30° tilt angle to enhance the turbulent heat dissipation effect.

[0009] Furthermore, the quick-release connector is a high-strength bolt, and the high-strength bolt is made of nano-alloy steel made of iron-based alloy, carbon, silicon, nickel, molybdenum and niobium. The nano-alloy steel is quenched at 850℃ and tempered at 250℃. The high-strength bolt has an anti-loosening diameter reduction section, and the diameter of its shank is reduced by 0.1-0.3mm at 1 / 3 of the distance from the bolt head to form a flexible deformation zone.

[0010] Furthermore, the signal output interface of the torque sensor is provided with a combined sealing ring on the outside, which includes a silicone sealing ring and a polyurethane dustproof ring disposed on the outside of the silicone sealing ring.

[0011] Furthermore, the wave generator includes at least two sets of rotating components. Each rotating component includes a mounting bracket for connecting with the motor shaft of an external drive motor and rollers rotatably mounted on the mounting bracket. The mounting bracket extends radially along the flexure of the reducer body. The vertical distance between the outer walls of the rollers of the two sets of rotating components is greater than the inner diameter of the flexure of the reducer body.

[0012] Furthermore, the outer wall of the roller of the wave generator is covered with a rubber layer, the hardness of which transitions from Shore 70A to 90A from the inside to the outside, and the surface of the rubber layer is provided with spiral grooves to increase the coefficient of friction with the flexible roller.

[0013] Furthermore, the mounting bracket has two radially protruding limiting plates at one end away from its rotation axis, and each of the two limiting plates has a through mounting hole. A limiting post is detachably installed in the mounting hole, and the roller rotates with the limiting post via a bearing.

[0014] Furthermore, a piezoelectric ceramic micro-actuator is embedded inside the limiting plate of the mounting bracket, which is connected to the torque sensor signal of the substrate through a flexible circuit; when the torque sensor detects a torque fluctuation of ≥5%, the micro-actuator drives the limiting column to move radially by about 0.05mm, thereby compensating for the meshing gap between the flexible wheel and the rigid wheel in real time.

[0015] Furthermore, the flex wheel of the reducer body has a rigid bottom wall and a flexible ring integrally formed with the rigid bottom wall. The flexible outer ring is provided with an external gear ring for meshing with the rigid wheel of the reducer body. The rigid bottom wall has a shaft hole in the middle, through which the motor shaft of the external drive motor passes and is detachably connected to the mounting bracket of the rotating component. The end face of the rigid bottom wall near the mounting bracket is provided with a plurality of radially arranged grooves, which are irregular stress grooves for dispersing the stress of the bottom wall of the flex wheel.

[0016] An assembly process for a modular harmonic reducer for a humanoid robot joint, as described in this invention, includes the following steps:

[0017] Step S1: Provide a mounting housing with assembly holes, an electric tightening tool, quick-release connectors, and a reducer body, and pre-assemble and position the reducer body.

[0018] Step S2: Insert the rigid wheel of the reducer body into the mounting housing along the axial direction, insert the flexible wheel and wave generator of the reducer body into the mounting housing and make the flexible wheel cooperate with the rigid wheel, fix the first limiting piece in the middle of the flexible wheel so that the central axis of the annular limiting boss coincides with the rotation axis of the bearing, and insert the quick-release connector into the assembly hole of the mounting housing.

[0019] Step S3: Use an electric tightening tool to apply torque at a uniform speed to connect and fix the quick-release connector and the base plate, and connect and fix the motor shaft of the drive motor to the wave generator of the reducer body.

[0020] Step S4: Inject viscoelastic damping adhesive between the first limiting member and the wave generator to form a 0.05mm-0.1mm damping buffer layer;

[0021] Step S5: Perform torque verification on the quick-release connector.

[0022] Furthermore, after step S3 is completed, the viscoelastic damping adhesive injected between the first limiting member and the wave generator is a polyether-modified silicone gel with a working temperature range of 40-120℃. The viscoelastic damping adhesive is used to absorb the vibration energy transmitted by the wave generator when the harmonic reducer is running at high speed.

[0023] The working principle of this invention is as follows: The motor shaft of the external drive motor is connected to the rotating component of the wave generator. The rotation of the motor drives the wave generator to rotate, and the rollers of the wave generator cause the flexible wheel to undergo elastic deformation. The outer gear ring of the flexible wheel meshes with the rigid wheel to achieve speed reduction transmission. A torque sensor monitors the torque transmitted by the reducer in real time and transmits the data to the control system through a signal output interface. During robot operation, the cooling channels on the mounting housing carry away the heat generated by the reducer through the circulation of coolant, ensuring that it operates within a suitable temperature range. The annular limiting boss of the first limiting component axially limits the bearing, and the quick-release connector tightly connects all components to form a stable transmission system, ensuring the precise movement and reliable operation of the humanoid robot's joints.

[0024] The beneficial effects of this invention are as follows: Through modular design, the invention organically combines components such as the mounting housing, reducer body, base plate, and first limiting member, utilizing quick-release connectors for rapid assembly, significantly improving production efficiency and maintenance convenience. The precise fit clearance between the annular limiting boss and the bearing outer ring effectively ensures stable bearing operation; the spiral cooling channel design greatly improves heat dissipation efficiency and reduces the reducer's operating temperature. The anti-loosening variable diameter section and flexible deformation zone design of the high-strength bolts enhance connection reliability and vibration resistance; the combined sealing ring design of the torque sensor improves signal transmission stability and dust and water resistance. The special structure of the wave generator and the irregular stress groove design of the flexible wheel further optimize transmission performance and extend the reducer's service life. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the harmonic reducer of the present invention in use with an external drive motor;

[0026] Figure 2 for Figure 1 A schematic diagram of the three-dimensional structure after partial cross-section;

[0027] Figure 3 This is a schematic diagram of the disassembled state of the harmonic reducer of the present invention;

[0028] Figure 4 This is a three-dimensional structural diagram of the mounting housing of the present invention after partial cross-section;

[0029] Figure 5 This is a schematic diagram of the structure of the flexible wheel in the reducer body of the present invention;

[0030] Figure 6 This is a schematic diagram of the decomposed state of the wave generator of the present invention;

[0031] Figure 7 This is a schematic diagram of the assembly process of the modular harmonic reducer for humanoid robot joints according to the present invention.

[0032] The reference numerals in the figures include:

[0033] 1. Mounting housing; 2. Reducer body; 3. Base plate; 4. First limiting component; 5. Drive motor; 6. Quick-release connector; 7. Torque sensor; 8. Bearing; 71. Combined sealing ring; 72. Silicone sealing ring; 73. Polyurethane dustproof ring; 11. Assembly hole; 12. Cooling channel; 21. Wave generator; 22. Flexible wheel; 221. Rigid bottom wall; 2210. Shaft hole; 2211. Groove; 222. Flexible ring; 223. External gear ring; 23. Rigid wheel; 24. Rotating component; 241. Mounting bracket; 242. Roller; 243. Limiting plate; 244. Mounting hole; 245. Limiting post; 41. Annular limiting boss. Detailed Implementation

[0034] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0035] Please see Figures 1 to 7 As shown, this invention proposes a modular harmonic reducer for humanoid robot joints, including a mounting housing 1, a reducer body 2, a base plate 3, and a first limiting member 4; the mounting housing 1 has an assembly hole 11 extending through it in the axial direction, the reducer body 2 includes a flexible wheel 22, a rigid wheel 23, and a wave generator 21, the first limiting member 4 has an annular limiting boss 41 for fixing an external bearing 8, the motor shaft of the external drive motor 5 is connected to the reducer body 2 via the bearing 8 and the annular limiting boss 41; it also includes a quick-release connector 6, the reducer body 2 is disposed inside the mounting housing 1, the quick-release connector 6 passes through the assembly hole 11 and connects the base plate 3 and the first limiting member 4, the base plate 3 is disposed between the external drive motor 5 and the mounting housing 1.

[0036] The mounting housing 1 refers to a support component with an axially through-hole structure. In this embodiment, it is formed into a cylindrical structure with assembly holes 11 using aluminum alloy casting technology, and the axial through-hole enables synchronous positioning of multiple components. The reducer body 2 includes a transmission component comprising a flexible wheel 22, a rigid wheel 23, and a wave generator 21. It uses the harmonic drive principle to construct a meshing pair, forming a precision reduction transmission system. The base plate 3 refers to a positioning component located between the drive motor 5 and the housing. It is implemented using a flange structure with a torque sensor 7, establishing a rigid connection interface between the motor and the reducer. The annular limiting boss 41 of the first limiting member 4 is a protruding structure used to constrain the axial displacement of the bearing 8. It is implemented using a precision-machined annular step, and the preload of the bearing 8 is controlled by dimensional matching. The quick-release connector 6 refers to a fastening element that enables quick assembly and disassembly. It is implemented using a variable diameter bolt structure, providing elastic deformation capability while ensuring connection strength.

[0037] Specifically, the axial through-hole 11 of the mounting housing 1 and the quick-release connector 6 form a coaxial positioning system, enabling multi-component alignment during assembly via a single-axis guide. The base plate 3 is positioned between the output end of the drive motor 5 and the housing, forming a three-point support structure to balance the transmission torque. The annular limiting boss 41 of the first limiting member 4 forms a clearance fit with the outer ring of the bearing 8, allowing for slight displacement adjustments during thermal expansion. The variable-diameter section of the quick-release connector 6 generates elastic deformation during pre-tightening, absorbing the impact load of the transmission system. The spiral cooling channel 12 extends axially along the housing, improving the heat exchange efficiency of the cooling medium by optimizing the flow path. The irregularly shaped stress grooves at the bottom of the flexible wheel 22 adopt an asymmetrical layout, transforming concentrated stress into a gradient distribution state.

[0038] Compared to existing technologies, the modular assembly structure changes the traditional split-type installation mode, simplifying the assembly process through single-axis positioning. The spiral cooling channel 12 replaces the traditional straight channel, increasing the turbulence of the cooling medium to improve heat dissipation efficiency. The variable-diameter bolt design breaks through the traditional equal-diameter connection method, reducing the stress concentration coefficient under the same preload. The clearance fit design between the annular limiting boss 41 and the bearing 8 differs from the traditional interference fit method, providing compensation space for thermal expansion. The irregular stress groove layout breaks the conventional symmetrical groove design, achieving optimized stress distribution.

[0039] Through the above technical solutions, this application achieves standardized operation of the harmonic reducer assembly process, reducing manual adjustment steps. It optimizes the thermal management efficiency of the transmission system, avoiding material property degradation caused by localized overheating. It improves the dynamic stability of the connection interface, effectively suppressing high-frequency vibration transmission. It enhances the fatigue resistance of key components, extending equipment maintenance cycles. It improves the torque fluctuation response of the transmission system and reduces operating noise levels.

[0040] Specifically, the mounting housing 1 has a spiral cooling channel 12 with a helix angle of 45°±5° inside. The cross-section of the cooling channel 12 is circular and its spiral axis is parallel to the central axis of the mounting housing 1.

[0041] The helix angle refers to the angle between the helix of the cooling channel 12 and the central axis of the mounting housing 1. Specifically, it can be achieved using machining parameters of 45°±5°. This angle range balances the relationship between coolant flow resistance and heat dissipation area. The circular cross-section reduces turbulence losses during coolant flow. The parallelism between the helix axis and the central axis of the mounting housing 1 means that the extension direction of the cooling channel 12 is aligned with the axial direction of the housing. Coaxial positioning fixtures ensure machining accuracy, and this layout achieves uniform heat distribution along the axial direction.

[0042] Specifically, the spiral cooling channel 12 achieves efficient heat exchange through optimized geometry. The spiral angle is controlled within the range of 45°±5°, ensuring sufficient heat dissipation area while reducing flow resistance, allowing the coolant to flow through the entire channel at a stable velocity. The circular cross-section design reduces fluid separation and maintains laminar flow to improve heat transfer efficiency. The structural layout, with the spiral axis parallel to the housing axis, creates a continuous, circling cooling path within a limited space, enhancing heat exchange by extending the coolant residence time. The axial distribution of the entire channel ensures uniform heat dissipation along the axial conduction path from the drive motor 5 to the reducer.

[0043] Compared to existing technologies, traditional straight or right-angle bend flow channels suffer from dead zones, leading to uneven heat dissipation. This solution eliminates localized vortex phenomena through a spiral flow channel structure. Compared to conventional flow channels with a spiral helix angle greater than 50°, this solution reduces the flow pressure drop by approximately 30% while maintaining the equivalent heat dissipation area. Compared to square or irregularly shaped flow channel cross-sections, the circular cross-section design improves the uniformity of flow velocity distribution by approximately 25%, avoiding the decrease in heat transfer efficiency caused by flow boundary layer separation.

[0044] Specifically, a detachable split liquid cooling module is added to the outer wall of the housing 1. The module consists of an aluminum alloy shell and an internally arranged honeycomb microchannel. The inlet or outlet of the microchannel is connected to the external cooling circulation system via a quick-connect connector.

[0045] During gearbox operation, external coolant is injected into the honeycomb microchannels of the liquid cooling module through quick-connect fittings. The staggered channel structure creates a spiral turbulent flow of coolant, rapidly dissipating the heat generated by the gearbox through the efficient thermal conductivity of the aluminum alloy casing. For maintenance, the liquid cooling module can be removed entirely by releasing the clips or bolts, eliminating the need to disassemble internal gearbox components and avoiding the cumbersome disassembly required for traditional cooling systems. The porous structure of the honeycomb microchannels provides a larger heat exchange area within the same volume, and combined with the thermal conductivity advantages of aluminum alloy, significantly improves heat dissipation efficiency.

[0046] Compared to existing technologies, the cooling channels 12 of traditional harmonic reducers are typically integrated inside the housing, making them impossible to disassemble and maintain independently. This necessitates shutdown and disassembly of the entire unit for maintenance. In contrast, this solution utilizes a modular, split design, making the cooling system an independent, replaceable unit. Maintenance requires only the disassembly of the module itself. Existing cooling channels 12 are mostly straight lines or simple spiral structures, resulting in short coolant flow paths and insufficient turbulence. In contrast, the honeycomb microchannels, through their staggered arrangement, significantly increase the effective heat exchange area and reduce flow disturbance. Traditional cooling pipes use flange or threaded connections, requiring specialized tools and time-consuming disassembly and assembly. This solution's quick-connect couplings allow for rapid manual connection while ensuring reliable sealing.

[0047] Specifically, in this embodiment, a silicon carbide thermally conductive coating is applied to the surface of the spiral cooling channel 12 inside the mounting housing 1, and an adaptive guide vane made of shape memory alloy is provided at the end of the spiral channel. When the coolant flow rate in the channel reaches a set value, the guide vane automatically expands to a specific angle to enhance the turbulent heat dissipation effect.

[0048] The silicon carbide thermally conductive coating is a composite ceramic layer formed on the inner wall of the spiral cooling channel 12 through physical vapor deposition, achieved using magnetron sputtering. This coating can effectively improve the heat transfer efficiency of the channel surface. The shape memory alloy guide plate is a thin metal sheet with a bidirectional shape memory effect, made of nickel-titanium alloy, which can trigger shape transformation according to changes in coolant flow rate.

[0049] Specifically, the silicon carbide coating enhances the thermal conductivity of the flow channel surface, enabling the heat generated by the reducer body 2 to be rapidly transferred to the coolant. The guide vanes at the end of the spiral flow channel remain flat in a static state to reduce flow resistance. When the coolant pumping power increases, causing the flow velocity to exceed a critical value, the guide vanes experience temperature changes due to fluid impact, triggering the phase transformation behavior of the shape memory alloy and causing it to unfold at a specific angle. After the guide vanes unfold, they alter the flow state of the coolant within the flow channel, changing it from laminar to turbulent flow, thereby enhancing the heat exchange efficiency between the fluid and the flow channel wall.

[0050] Compared to existing technologies, traditional heat dissipation solutions often employ fixed-structure heat dissipation channels, making it impossible to dynamically adjust the heat dissipation intensity according to actual operating conditions. This solution, however, achieves proactive optimization of heat dissipation performance through the synergistic effect of intelligent responsive flow guides and a high thermal conductivity coating. Existing passive heat dissipation methods are prone to heat accumulation at low flow rates and cannot overcome laminar flow limitations at high flow rates. This solution, on the other hand, achieves adaptive heat dissipation efficiency based on operating conditions through a flow rate-triggered flow guide mechanism.

[0051] Through the above technical solution, this application can actively enhance heat dissipation intensity when the harmonic reducer is running under high load, avoiding material thermal expansion and decreased meshing accuracy caused by temperature rise, while ensuring low energy consumption operation under low load conditions. The turbulent state formed in the flow channel effectively improves the contact efficiency between the coolant and the flow channel wall, and the uniform coverage of the silicon carbide coating avoids the formation of local hot spots, thereby maintaining the dimensional stability of the overall structure of the reducer.

[0052] Specifically, the quick-release connector 6 is a high-strength bolt. The high-strength bolt is made of nano-alloy steel made of iron-based alloy, carbon, silicon, nickel, molybdenum and niobium. The nano-alloy steel is quenched at 850℃ and tempered at 250℃. The high-strength bolt has an anti-loosening diameter reduction section. The diameter of its shank is reduced by 0.1-0.3mm at 1 / 3 of the distance from the bolt head to form a flexible deformation zone.

[0053] Among them, the iron-based alloy composite carbon, silicon, nickel, molybdenum, and niobium material of nano-alloy steel refers to an alloy system based on iron, with the addition of carbon, silicon, nickel, molybdenum, and niobium elements. Powder metallurgy is used to achieve a uniform nanoscale grain distribution. Carbon strengthens the grain boundary structure, molybdenum and niobium form a high-temperature stable phase, and nickel and silicon improve the material's toughness. The anti-loosening diameter transition section refers to the area where the bolt shank's diameter decreases at 1 / 3 of the distance from the bolt head. Precision turning creates a gradually changing diameter structure. This area undergoes elastic deformation under alternating loads, changing the bolt's stress distribution pattern. The 850℃ quenching and 250℃ low-temperature tempering treatment involves heating the alloy material to its austenitizing temperature, rapidly cooling it to form a martensitic structure, and then adjusting the internal stress state through low-temperature tempering. This process is achieved using a controlled atmosphere heat treatment furnace, resulting in a balance between high strength and impact resistance.

[0054] Specifically, carbon in the iron-based alloy enhances material hardness through interstitial solid solution strengthening, while molybdenum and niobium form carbide phases that maintain structural stability at high temperatures, and nickel and silicon inhibit crack propagation. Quenching treatment creates a high-hardness martensitic matrix, and low-temperature tempering eliminates quenching stress while retaining sufficient strength. The reduced diameter design of the anti-loosening reducing section causes preferential elastic deformation in this area under preload, absorbing vibration energy generated during robot joint operation. Simultaneously, deformation adjustment maintains constant contact pressure in the threaded engagement section. When external dynamic loads cause micro-displacement at the connection interface, the flexible deformation zone compensates for the displacement through its own elastic deformation, preventing slippage and wear between the threads, thus preventing preload attenuation.

[0055] Compared to existing technologies, traditional high-strength bolts, reinforced with a single alloy element, are prone to stress concentration and fracture under dynamic loads. They also lack active anti-loosening structures, relying solely on thread friction to maintain the connection. Conventional heat treatment processes struggle to balance hardness and toughness, and high-temperature tempering can lead to strength reduction. This solution achieves synergistic optimization of material properties through multi-component nano-alloy design. The elastic deformation mechanism of the anti-loosening diameter section actively adapts to dynamic load changes, and the heat treatment process precisely controls the material's microstructure, thus solving the reliability problems of traditional fasteners caused by fatigue fracture and vibration loosening.

[0056] Through the above technical solutions, this application achieves improved dynamic stability of the connection structure of the robot joint transmission system, prevents bolts from loosening and failing under long-term alternating loads, effectively absorbs the vibration energy generated by the operation of the harmonic reducer, and ensures reliable connection of the joint module under high-speed and heavy-load conditions. The elastic compensation mechanism of the flexible deformation zone maintains constant compressive stress between the threaded pairs, avoids preload loss caused by fretting wear, and extends the service life of key connecting components.

[0057] Specifically, the outer wall of the roller 242 of the wave generator 21 is covered with a rubber layer. The hardness of the rubber layer transitions from Shore 70A to 90A from the inside to the outside. The surface of the rubber layer is provided with spiral grooves to increase the coefficient of friction with the flexible roller 22.

[0058] The hardness gradient of the rubber layer refers to the continuous change from soft to hard from the inside to the outside of the material. This is achieved by adjusting the proportion of vulcanizing agent in stages through a layered injection molding process. The inner layer of low-hardness rubber absorbs impact energy at the moment of contact, while the outer layer of high-hardness rubber provides stable support.

[0059] Among them, the spiral grooves refer to the continuous grooves formed along the circumference of the roller 242 with a constant pitch. Specifically, they can be prepared by laser engraving or mold forming process. The grooves form micro fluid channels, reduce lubricant retention between contact surfaces, and increase the effective friction area.

[0060] Specifically, during the contact between roller 242 and flexible wheel 22, the inner low-hardness rubber undergoes elastic deformation first, absorbing the transmission impact force through material compression and avoiding instantaneous vibration caused by hard contact; the outer high-hardness rubber maintains the stiffness of the contact surface, ensuring stable transmission of torque. The spiral grooves generate tangential resistance during relative motion, and the edges of the grooves 2211 form localized high-pressure zones, increasing the coefficient of friction through a microscopic locking effect. The hardness gradient of the rubber layers and the surface texture work synergistically, preventing stress fatigue cracks caused by materials of single hardness under long-term alternating loads, and suppressing vibration transmission by optimizing the contact stress distribution.

[0061] Through the above technical solutions, this application effectively improves the friction coefficient between the wave generator 21 and the flexible wheel 22, and reduces energy loss during transmission; through the layered buffer design of the contact surface, the transmission of high-frequency vibration to the mechanical structure is significantly reduced, and operating noise is suppressed; the fluid channel formed by the spiral groove can discharge impurities from the contact surface in a timely manner, and extend the service life of the rubber layer.

[0062] Specifically, the wave generator 21 includes at least two sets of rotating members 24. Each rotating member 24 includes a mounting bracket 241 for connecting with the motor shaft of an external drive motor 5 and a roller 242 rotatably mounted on the mounting bracket 241. In this embodiment, the roller 242 is preferably a ball bearing. The mounting bracket 241 extends along the radial direction of the flexure 22 of the reducer body 2. The vertical distance between the outer walls of the rollers 242 of the two sets of rotating members 24 is greater than the inner diameter of the flexure 22 of the reducer body.

[0063] The rotating component 24 refers to the power transmission unit consisting of a mounting frame 241 and a roller 242, which is made of carbon steel. The mounting frame 241 is detachably connected to the motor shaft, and the roller 242 rotates through a bearing 8. This structure disperses the local stress during the meshing of the flexible wheel 22 through multi-point contact.

[0064] The installation bracket 241 extends along the radial direction of the flex wheel 22, meaning that the length of the installation bracket 241 is parallel to the radial axis of the flex wheel 22. This is achieved using an integrated casting process. This design ensures that the movement trajectory of the roller 242 is consistent with the deformation direction of the flex wheel 22, reducing the impact caused by deviation in the movement direction.

[0065] The fact that the distance between the outer walls of the two sets of rollers 242 is greater than the inner diameter of the flexible wheel 22 refers to the geometric constraint formed by the installation position of the rollers 242, which is achieved by adjusting the length of the mounting bracket 241. This distance forms a preload on the flexible wheel 22, which maintains contact pressure during dynamic engagement to achieve a deceleration effect.

[0066] Specifically, the mounting bracket 241, extending radially along the flexible wheel 22, ensures that the movement direction of the roller 242 is synchronized with the deformation direction of the flexible wheel 22, guaranteeing a uniform distribution of the contact surface. The two sets of rotating components 24 form a symmetrical support structure. The geometric constraint that the distance between the rollers 242 is greater than the inner diameter of the flexible wheel 22 generates an initial preload during assembly, ensuring that the flexible wheel 22 and the rigid wheel 23 maintain effective contact at all times. When the motor drives the wave generator 21 to rotate, the contact point between the roller 242 and the inner wall of the flexible wheel 22 moves periodically circumferentially, dispersing the single-point load through multi-point contact and reducing vibration transmission caused by localized stress concentration. The continuous action of the preload compensates for dynamic changes in the meshing clearance, preventing impact vibrations caused by instantaneous increases in clearance.

[0067] Compared with existing technologies, traditional wave generators 21 mostly adopt a single elliptical cam structure, which suffers from problems such as concentrated contact points and uneven stress distribution. This solution improves single-point contact to multi-point contact through the symmetrical layout of multiple sets of independent rotating parts 24, forming a redundant support structure. In existing technologies, gap compensation usually relies on passive adjustment of elastic elements, while this solution achieves active gap control through the preload generated by geometric constraints, improving dynamic stability while maintaining structural rigidity.

[0068] Through the above technical solution, this application effectively suppresses the vibration transmission caused by gap fluctuations during the meshing of the flexible wheel 22 and the rigid wheel 23, thereby improving the smoothness of joint transmission. The multi-point contact structure reduces the risk of local stress concentration, and the constant contact pressure maintained by the preload avoids impact noise caused by sudden gap changes, thus improving the accuracy and reliability of the humanoid robot joint during high-speed movement.

[0069] Specifically, the flexible wheel 22 of the reducer body 2 is integrally formed by precision forging and CNC machining using high-strength alloy steel (40CrNiMoA). The rigid bottom wall 221 has a thickness of 5mm, the flexible ring 222 has a wall thickness of 1mm, and the external gear ring 223 adopts a standard involute tooth profile with 200 teeth and a module of 0.3 to ensure precise meshing with the rigid wheel 23. A shaft hole 2210 with a diameter of 30mm is machined in the center of the rigid bottom wall 221. The inner wall surface of the shaft hole 2210 has a surface finish of Ra0.4. The motor shaft is detachably connected to the mounting bracket 241 of the rotating part 24 of the wave generator 21 via a keyway and is fixed with M6 bolts. Six radially distributed irregular stress grooves are machined on the end face of the rigid bottom wall 221 near the mounting bracket 241. The grooves are triangular in shape, 1.5mm deep, 0.5-1mm wide, 8mm apart, and have a corner radius of 0.3mm. The groove shape is optimized to disperse stress concentration.

[0070] During manufacturing, the blank is first forged, then quenched at 850℃ and tempered at 200℃. The gear ring and stress grooves are then precision machined using a five-axis CNC machine tool to ensure a form and position tolerance of ≤0.02mm. Compared to existing technologies, the irregularly shaped stress grooves effectively reduce stress concentration on the bottom wall, extending the fatigue life of the flexible gear 22. The one-piece molding improves structural rigidity, reduces assembly errors, and further enhances meshing accuracy.

[0071] This application further proposes an assembly process for a modular harmonic reducer for humanoid robot joints, including the following steps:

[0072] First, a mounting housing 1 with multiple axial through mounting holes 11 is provided, along with an adjustable torque electric tightening tool, a set of multiple sets of high-strength quick-release connectors 6, a pre-adjusted reducer body 2, and a matching external drive motor 5.

[0073] At the initial stage of assembly, the operator pre-positions and assembles the flexible wheel 22, rigid wheel 23 and wave generator 21 in the reducer body 2 on the external platform to ensure that the gear meshing clearance is within the design tolerance. Then, the rigid wheel 23 assembly is inserted into the pre-positioned cavity inside the mounting housing 1 along the axial direction of the housing, and the flexible wheel 22 and wave generator 21 assembly are inserted in the same direction to achieve high-precision meshing with the rigid wheel 23.

[0074] The flexible wheel 22 is centered by a first limiting member 4 with an annular limiting boss 41. The central axis of this limiting member must be strictly coaxial with the rotation axis of the bearing 8 to ensure the concentricity of the entire system. Next, the operator inserts the high-strength quick-release connector 6 through the mounting hole 11 outside the housing and through the installation channel of the limiting member. At this time, a uniform torque is applied to the connector by an electric tightening tool to rigidly fix the reducer body 2, the base plate 3 and the housing. At the same time, the motor shaft of the drive motor 5 is precisely inserted into the connecting hole in the center of the wave generator 21 and fixed to the mounting bracket 241 by thread locking or keyway, ensuring power input efficiency and centering accuracy.

[0075] After connection, a high-performance viscoelastic damping adhesive, preferably polyether-modified silicone gel, is injected into the gap between the first limiting member 4 and the wave generator 21. This gel possesses excellent heat resistance and vibration damping properties. The adhesive layer is controlled between 0.05mm and 0.1mm to ensure uniform filling and no air bubbles. This gel maintains stable viscoelasticity within a temperature range of 40℃ to 120℃, effectively absorbing high-frequency vibrations and shock waves transmitted from the wave generator 21 to the flexible wheel 22 and housing structure during high-speed operation of the reducer, reducing system noise and mechanical stress concentration. Finally, a digital torque verification tool is used to precisely verify the locking torque applied to each quick-release connector 6 to confirm whether it meets the design torque requirements (e.g., 30±2 N·m for each bolt), ensuring the reliability and consistency of the structural connection.

[0076] Compared to the traditional, complex, and difficult-to-reproduce reducer assembly process, this invention significantly reduces the technical threshold for manual assembly through modular segmented structural design and standardized assembly technology, achieving a rapid assembly effect with high efficiency, low error, and strong stability. The introduced limiting components, combined with the vibration-damping adhesive layer structure, effectively buffer the periodic impacts of the wave generator 21, reduce dynamic load fluctuations in the joint structure, and improve the overall reliability and lifespan of the humanoid robot's joint transmission system. Specifically, the assembly process achieves synergistic optimization of structural stability and vibration suppression through phased implementation of mechanical connections and damping filling.

[0077] The pre-assembly positioning step provides a precise reference surface for subsequent assembly, ensuring the axial alignment accuracy of each component. The axial fitting design of the mounting housing 1, combined with the use of quick-release connectors 6, enables rapid positioning and fixing of modular components. The electric tightening tool applies torque at a uniform speed, avoiding uneven preload distribution caused by manual operation. The timing of injecting viscoelastic damping adhesive after completing the mechanical connection ensures that the adhesive fully fills the structural gaps before curing, while also preventing the curing stress of the adhesive from affecting the assembly accuracy. The increased fluidity of polyether-modified silicone gel with increasing temperature during the initial stage of equipment operation allows it to penetrate into the microscopic depressions of the mating surfaces, forming a continuous buffer layer. Finally, the torque verification step verifies the reliability of the connection, forming a complete closed-loop control of assembly quality.

[0078] Compared with existing technologies, traditional assembly processes typically employ modular assembly and manual tightening, resulting in stress concentration and a lack of vibration damping measures. This invention, through a modular quick-assembly structure design combined with a staged injection of damping material, achieves a balance between structural stiffness and vibration damping while maintaining assembly efficiency.

[0079] Through the above technical solutions, this application solves the technical problems of complex assembly and insufficient vibration suppression in traditional harmonic reducers, achieving stable connection and precise transmission under high dynamic conditions. The modular assembly process simplifies on-site operation, and the quick-release structure and electric tightening improve assembly efficiency. The introduction of a viscoelastic damping layer effectively absorbs high-frequency vibration energy in the transmission system, reducing the risk of resonance. Phased assembly timing control and final torque verification form a complete quality control chain, ensuring that the reducer maintains stable motion accuracy and structural reliability during long-term operation.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A modular harmonic reducer for humanoid robot joints, characterized in that: The system includes a mounting housing (1), a reducer body (2), a base plate (3), and a first limiting member (4). The mounting housing (1) has a cavity for accommodating the reducer body (2), and the wall of the mounting housing (1) has an assembly hole (11) that extends through it in the axial direction. The reducer body (2) includes a flexible wheel (22), a rigid wheel (23), and a wave generator (21). The first limiting member (4) has an annular limiting boss (41) for fixing an external bearing (8). An external drive motor... (5) The motor shaft is connected to the wave generator (21) of the reducer body (2) via a bearing (8) and an annular limiting boss (41); it also includes a quick-release connector (6), the reducer body (2) is disposed in the mounting housing (1), the quick-release connector (6) passes through the assembly hole (11) and connects to the base plate (3) to limit the reducer body (2) between the mounting housing (1) and the base plate (3), the base plate (3) is disposed between the external drive motor (5) and the mounting housing (1); The mounting housing (1) has a spiral cooling channel (12) with a helix angle of 45°±5° inside. The cross-section of the cooling channel (12) is circular and its spiral axis is parallel to the central axis of the mounting housing (1). The spiral cooling channel inside the housing is coated with a silicon carbide thermal conductive coating with a thickness of 10-20 micrometers. The end of the spiral channel is equipped with an adaptive guide vane made of shape memory alloy. When the coolant flow rate in the channel is ≥1.5m / s, the guide vane automatically expands to a 30° tilt angle to enhance the turbulent heat dissipation effect. The outer wall of the mounting housing is provided with a detachable split liquid cooling module, which consists of an aluminum alloy shell and an internally arranged honeycomb microchannel. The inlet / outlet of the microchannel is connected to the external cooling circulation system through a quick-connect connector.

2. The modular harmonic reducer for humanoid robot joints according to claim 1, characterized in that: The radial length of the annular limiting boss (41) is 1.2-1.5 times the thickness of the outer ring of the outer bearing (8), and a 0.02-0.05mm fitting clearance is formed between the annular limiting boss (41) and the outer ring of the bearing (8).

3. The modular harmonic reducer for humanoid robot joints according to claim 1, characterized in that: The quick-release connector (6) is a high-strength bolt. The high-strength bolt is made of nano-alloy steel made of iron-based alloy, carbon, silicon, nickel, molybdenum and niobium. The high-strength bolt has an anti-loosening diameter section. The diameter of the anti-loosening diameter section is reduced by 0.1-0.3 mm near the bolt head to form a flexible deformation zone.

4. The modular harmonic reducer for humanoid robot joints according to claim 1, characterized in that: The modular harmonic reducer also includes a torque sensor (7) that is connected to the reducer body (2). The signal output interface of the torque sensor (7) is provided with a combined sealing ring (71). The combined sealing ring (71) includes a silicone sealing ring (72) and a polyurethane dustproof ring (73) provided on the outside of the silicone sealing ring (72).

5. The modular harmonic reducer for humanoid robot joints according to claim 1, characterized in that: The wave generator (21) includes at least two sets of rotating parts (24). Each rotating part (24) includes a mounting bracket (241) for connecting with the motor shaft of an external drive motor (5) and a roller (242) rotatably mounted on the mounting bracket (241). The mounting bracket (241) extends radially along the flexure (22) of the reducer body (2). The vertical distance between the outer walls of the rollers (242) of the two sets of rotating parts (24) is greater than the inner diameter of the flexure (22) of the reducer body (2).

6. The modular harmonic reducer for humanoid robot joints according to claim 5, characterized in that: The mounting bracket (241) has two radially protruding limiting plates (243) at one end away from its rotation axis. Each of the two limiting plates (243) has a through mounting hole (244). A limiting post (245) is detachably installed in the mounting hole (244). The roller (242) rotates with the limiting post (245) via a bearing (8).

7. The modular harmonic reducer for humanoid robot joints according to claim 5, characterized in that: The flex wheel (22) of the reducer body (2) has a rigid bottom wall (221) and a flexible ring (222) integrally formed with the rigid bottom wall (221). The flexible ring (222) is provided with an external gear ring (223) for meshing with the rigid wheel (23) of the reducer body (2). The rigid bottom wall (221) is provided with a shaft hole (2210) in the middle. The motor shaft of the external drive motor (5) passes through the shaft hole (2210) and is detachably connected to the mounting bracket (241) of the rotating part (24). The end face of the rigid bottom wall (221) near the mounting bracket (241) is provided with a plurality of grooves (2211). The grooves (2211) are irregular stress grooves for dispersing the stress of the rigid bottom wall.

8. An assembly process for assembling the modular harmonic reducer for humanoid robot joints according to any one of claims 1-7, characterized in that: Includes the following steps: Step S1: Provide an installation housing (1) with an assembly hole (11) and a pre-fabricated spiral cooling channel, an electric tightening tool, a quick-release connector (6), and a reducer body (2), and pre-assemble and position the reducer body (2); wherein the spiral cooling channel inside the installation housing is pre-fabricated with a silicon carbide thermal conductive coating with a thickness of 10-20 micrometers, and the end of the spiral channel is pre-fabricated with an adaptive guide plate made of shape memory alloy material, wherein the guide plate can automatically expand to a 30° tilt angle when the coolant flow rate in the channel is ≥1.5m / s to enhance the turbulent heat dissipation effect; Step S2: Mount the housing (1) axially onto the outside of the rigid wheel of the reducer body (2), place the flexible wheel (22) and wave generator (21) of the reducer body (2) into the housing (1) and make the flexible wheel (22) cooperate with the rigid wheel (23), fix the first limiting piece (4) in the middle of the flexible wheel (22) so that the central axis of the annular limiting boss (41) coincides with the rotation axis of the bearing (8), and insert the quick-release connector (6) into the assembly hole (11) of the housing (1). Step S3: Use an electric tightening tool to apply torque at a uniform speed to connect and fix the quick-release connector (6) to the base plate (3), fix the base plate (3) on the drive motor (5), and connect and fix the motor shaft of the drive motor (5) to the wave generator (21) of the reducer body (2). Step S4: Inject viscoelastic damping adhesive between the first limiting member (4) and the wave generator (21) to form a 0.05mm-0.1mm damping buffer layer; Step S5: Add a detachable split liquid cooling module to the outer wall of the mounting housing (1). The module consists of an aluminum alloy shell and an internally arranged honeycomb microchannel. The inlet / outlet of the microchannel is connected to the external cooling circulation system through a quick-connect connector.

9. The assembly process for assembling a modular harmonic reducer for a humanoid robot joint according to claim 8, characterized in that: After step S3 is completed, the viscoelastic damping adhesive injected between the first limiting member (4) and the wave generator (21) is a polyether modified silicone gel with a working temperature range of 40-120℃. The viscoelastic damping adhesive is used to absorb the vibration energy transmitted by the wave generator (21) when the harmonic reducer is running at high speed.

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