Pre-tensioned crossed roller humanoid robot bearing

Abstract

The application relates to the technical field of cross-roller bearings, in particular to a pre-tightening type cross-roller humanoid robot bearing which comprises a bearing inner ring and a bearing outer ring, a raceway is formed on the bearing inner ring and the bearing outer ring, rollers are arranged on the raceways, an oil injection port is formed on the bearing outer ring, a sealing cover is arranged on the oil injection port, an installation groove is formed on the bearing outer ring, an oil storage bag is arranged in the installation groove, an oil outlet is formed on the oil storage bag, and the oil outlet is communicated with the raceway inside the oil storage bag. According to the design that the installation groove is formed on the bearing outer ring and the oil storage bag is arranged in the installation groove, when the temperature rises, the gas in the pressure chamber expands and presses the oil storage bag, so that the lubricating oil is squeezed out; when the temperature decreases, the situation is reversed, thereby the problems that the oil supply is excessive at low speed and low temperature and the oil supply is insufficient at high speed and high temperature can be avoided, the structure design is simple and compact, no external lubricating device needs to be additionally arranged or the bearing volume needs to be enlarged, and the structure is highly suitable for the narrow space of a robot joint.

Description

Technical Field

[0001] This invention relates to the field of crossed roller bearing technology, specifically a preloaded crossed roller humanoid robot bearing. Background Technology

[0002] Humanoid robots have extremely limited joint space and need to frequently cope with multi-dimensional composite loads such as radial, axial, and overturning loads generated by starting, stopping, changing direction, and carrying heavy loads. Their matching bearings must have a compact structure, high rigidity, high rotational accuracy, and excellent service durability. Crossed roller bearings, with their rollers arranged in a 90° perpendicular cross pattern, can bear multi-directional forces with a single bearing set, significantly replacing the traditional solution that requires two sets of bearings and greatly saving axial installation space. Therefore, they have become the ideal choice in this field.

[0003] At the material level, these bearings are typically manufactured using high-carbon chromium bearing steel (such as GCr15), achieving a "hard surface, tough core" characteristic through specific heat treatment processes. The surface acquires a high-hardness, wear-resistant layer to resist rolling contact fatigue, while the core retains sufficient toughness to absorb impacts and vibrations during robot movement. However, currently, the conventional maintenance method for these bearings involves manually adding a constant amount of lubricating oil periodically. This approach has significant limitations in adaptability to different operating conditions: firstly, under low-speed and low-temperature conditions, the oil supply is relatively excessive. Excess lubricating oil, agitated by the rolling elements, generates additional viscous resistance, reducing transmission efficiency. Efficiency; secondly, under high-speed and high-temperature conditions, the oil supply is relatively insufficient, and the temperature rise causes the viscosity of the lubricating oil to drop sharply, the oil film thickness to decrease sharply or even break, which in turn causes direct metal-to-metal contact between the rolling elements and the raceway, accelerating abrasive wear and adhesive wear. In particular, although high-carbon chromium bearing steel has excellent wear resistance and fatigue life under ideal lubrication conditions, once it loses cooling and isolation protection due to lubrication failure, its overall brittle characteristics will be exposed. Without cooling and oil film isolation, the bearing is very prone to excessive wear or even sudden seizure or breakage.

[0004] To address the aforementioned issues, existing technologies offer several solutions. For example, patent application number CN202511814159.1 provides a lightweight thin-walled crossed roller bearing for high-precision industrial robots. This invention utilizes an adaptive lubrication assembly based on a shape memory alloy spring to adjust the lubricating oil supply by driving a valve core through temperature changes. Simultaneously, it incorporates a recovery assembly and a heat dissipation assembly to achieve residual oil recovery and efficient heat dissipation, thereby improving lubrication efficiency and bearing life. However, this design requires the installation of a storage cavity, external delivery pipeline, and return oil pipeline on the mounting base, increasing system complexity and external space occupation, making it difficult to adapt to application scenarios with extremely limited space, such as humanoid robot joints. Summary of the Invention

[0005] The purpose of this invention is to provide a preloaded cross-roller humanoid robot bearing to solve the problem that conventional automatic oil supply designs are complex, occupy a large amount of space, and are difficult to adapt to application scenarios where robot joints are in extremely limited space.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A preloaded cross-roller humanoid robot bearing includes an inner ring and an outer ring. Raceways are formed on both the inner and outer rings, and rollers are arranged on the raceways. An oil inlet is provided on the outer ring, and a sealing cap is provided on the oil inlet. An mounting groove is formed on the outer ring, and an oil reservoir is disposed inside the mounting groove. The oil reservoir is fixedly connected to a plane near the raceway side of the mounting groove. A pressure chamber is formed on the outer ring, and the pressure chamber communicates with the mounting groove. An oil outlet is formed on the oil reservoir, and the oil outlet connects the interior of the oil reservoir to the raceway.

[0007] This invention, through the design of an installation groove on the outer ring of the bearing and the inclusion of an internal oil reservoir, achieves an adaptive lubrication mechanism that automatically adjusts the lubrication supply according to changes in the bearing's operating temperature. When the temperature rises, the gas inside the pressure chamber expands, compressing the oil reservoir and forcing out the lubricating oil; conversely, when the temperature drops, the opposite occurs. This precisely avoids the problem of excessive oil supply causing roller agitation and additional resistance in traditional constant-volume lubrication methods under low-speed, low-temperature conditions. Simultaneously, it effectively prevents direct metal-to-metal contact and abnormal wear caused by insufficient oil supply and oil film thinning and rupture under high-speed, high-temperature conditions. This significantly improves the reliability and durability of the bearing under frequent starts and stops, changes in direction, and combined loads. Furthermore, the oil reservoir, as an internal oil storage chamber, can... Sufficient lubricant reserves and long-term automatic replenishment not only simplify maintenance operations and reduce the frequency and cost of manual periodic lubrication, but also reduce grease waste and external contamination risks through on-demand supply. Furthermore, the simple and compact structure integrates all components inside the bearing outer ring, perfectly fitting the compact installation space requirements of preloaded crossed roller bearings. No additional external lubrication devices or bearing volume are required. While ensuring high bearing rigidity, high rotational accuracy, and anti-tipping capability, it further optimizes the stability and response consistency of joint movements, significantly extending the overall service life of the bearing under harsh operating conditions and improving the operational safety of the humanoid robot joint system.

[0008] Preferably, the oil reservoir has a corrugated shell on its side, a rectangular frame is slidably connected inside the mounting groove, and the side of the oil reservoir away from the raceway is fixedly connected to the rectangular frame.

[0009] This invention utilizes a corrugated shell on the side of the oil reservoir, combined with a rectangular frame slidably connected inside the mounting groove. The side of the oil reservoir furthest from the raceway is fixedly connected to the rectangular frame. The corrugated shell, with its bellows-like expansion and contraction characteristics, provides precise axial constraint to the oil reservoir under pressure deformation. This ensures the oil reservoir always contracts and expands regularly in a direction perpendicular to the raceway, effectively preventing lateral twisting or radial displacement of the oil reservoir caused by high-frequency vibration, abrupt changes in direction, or impact loads on the humanoid robot bearing. This completely avoids friction damage or displacement jamming of the oil reservoir against the inner wall of the mounting groove due to irregular oscillation. Simultaneously, the structural rigidity of the corrugated shell ensures the oil reservoir will not slide or misalign relative to the mounting groove due to centrifugal force or vibration generated by the bearing's own operation. Meanwhile, the rectangular frame, as a rigid support component, is slidably connected inside the mounting groove, significantly enhancing the overall structural strength and support stability of the oil reservoir's back side, making it more resistant to pressure when compressed by gas expansion within the pressure chamber. With uniform area and consistent pressure distribution, the oil reservoir avoids premature fatigue failure caused by localized stress concentration. Furthermore, the precision sliding pair formed by the rectangular frame and the inner wall of the mounting groove further constrains the directional sliding stroke of the oil reservoir along the axis of the mounting groove, ensuring a consistent reciprocating motion trajectory during thermal expansion and contraction cycles caused by temperature changes. This guarantees a precise linear response of oil output to temperature variations and, through the mechanical limiting effect of the rectangular frame, avoids the risk of rupture or oil supply interruption caused by excessive expansion or compression of the oil reservoir. Therefore, this design significantly extends the service life of the oil reservoir and the entire lubrication structure. It also allows for more efficient transmission of extrusion pressure to the oil reservoir when the gas inside the pressure chamber expands, improving the responsiveness and consistency of lubricant supply. This ensures that the internal lubrication channels of the preloaded crossed roller bearing remain unobstructed and the oil film thickness is stable without increasing external space requirements, comprehensively enhancing the safety and motion continuity of the humanoid robot's joints during high-load movements.

[0010] Preferably, the outer ring of the bearing has an annular arc groove and an oil collection groove, which is connected to the oil outlet. The depth of the annular arc groove is A, where 1mm ≤ A ≤ 2mm.

[0011] This invention utilizes a structural design that incorporates an annular arc groove on the outer ring of the bearing, along with an oil collection groove connected to the oil outlet. When the humanoid robot bearing operates at high speed, the lubricating oil accumulates and adheres to the raceway surface of the outer ring due to centrifugal force. The lubricating oil then accumulates in the annular arc groove, creating a localized enrichment area within the groove. The lubricating oil then flows through the annular arc groove and accumulates again in the oil collection groove, ensuring the oil outlet is always submerged in lubricating oil. This allows the oil reservoir's outlet to consistently contact and draw in sufficient liquid lubricating oil without drawing in excessive air due to uneven oil distribution or a thin oil layer on the raceway surface. This ensures the oil reservoir can stably replenish and recover sufficient and pure lubricating oil during every thermal expansion and contraction cycle, thereby significantly improving the adaptive lubrication system. The system ensures reliable circulation and continuous oil supply. Furthermore, because the depth A of the circular groove is strictly limited to between 1mm and 2mm, this minimal depth ensures that the annular groove has sufficient volume to accommodate the amount of lubricating oil ejected by centrifugal force, while completely avoiding the risk of weakening the structural strength of the bearing outer ring or causing stress concentration due to excessive groove depth. The continuous annular structure of the circular groove provides auxiliary lubrication to the contact area between the roller ends and the flange, effectively reducing the boundary friction coefficient and suppressing localized wear. Ultimately, without increasing bearing manufacturing costs or assembly difficulty, the system significantly optimizes the temperature rise control and operational smoothness of the humanoid robot joint bearing under frequent start-stop, speed change, and heavy-load impact conditions, comprehensively improving the long-term reliability and lifespan of the bearing in harsh service environments.

[0012] Preferably, an oil supply pipe is provided on the oil inlet, one end of the oil supply pipe extends into the oil reservoir, the oil supply pipe is slidably connected to the oil inlet, the sealing cap is threadedly connected to the oil supply pipe, a push block is provided on the oil supply pipe, a spring is provided between the push block and the inner wall of the outer ring of the bearing, and the push block contacts the rectangular frame.

[0013] This invention, by setting an oil delivery pipe at the oil inlet and extending one end of the oil delivery pipe into the oil reservoir, allows for the direct injection of fresh external lubricating oil into the reservoir during subsequent maintenance and lubrication oil replacement. Simultaneously, the existing old lubricating oil inside the reservoir can be discharged or replaced via the same oil delivery pipe, achieving simultaneous and thorough replacement of the lubricating oil stored in the reservoir. This avoids the need for separate cleaning of the old oil inside the reservoir, significantly improving the maintenance convenience of the bearing lubrication system. Secondly, by setting a spring and having a pusher block contact the rectangular frame, when the sealing cap is tightened, the sealing cap, through its threaded connection, fixes the oil delivery pipe and pusher block in their initial positions and compresses the spring. At this time, the oil reservoir maintains its normal working volume. When the sealing cap is unscrewed to replace the lubricating oil, the oil delivery pipe loses the threaded connection and limiting constraint of the sealing cap, and the spring releases its elastic potential energy from the compressed state, pushing the oil delivery pipe to deliver oil. The first spring then drives the pusher block to move towards the oil reservoir. The pusher block transmits the thrust to the rectangular frame through contact with the rectangular frame, further squeezing the oil reservoir. This automatically forces the old lubricating oil inside the reservoir to be emptied during the oil change process, eliminating the need for external tools and avoiding the inconvenience of operation in confined spaces. This significantly simplifies the oil change process and shortens maintenance time. At the same time, the automatic pushing force of the first spring ensures that the oil reservoir is subjected to uniform and continuous squeezing during the oil draining process, allowing the old lubricating oil to be fully drained with minimal residue inside the reservoir. This effectively avoids the mixing of new and old oil and the decline in lubrication performance caused by incomplete drainage of old oil. This design significantly reduces the operational difficulty of changing the lubricating oil in crossed roller bearings, further ensuring the initial cleanliness and oil supply accuracy of the lubrication system after each oil change. Ultimately, it comprehensively improves the long-term reliability, maintenance economy, and practical engineering application feasibility of the oil reservoir under harsh service conditions.

[0014] Preferably, an oil supply pipe 2 is coaxially slidably connected to the first oil supply pipe. The second oil supply pipe is located inside the oil reservoir. A spherical valve core is provided at one end of the second oil supply pipe. A spring 2 is provided between the spherical valve core and the second oil supply pipe. A sealing surface is provided at one end of the second oil supply pipe. The spherical valve core and the sealing surface cooperate with each other. A limit block is fixedly connected to one end of the second oil supply pipe.

[0015] This invention achieves this by coaxially slidingly connecting oil pipe two to oil pipe one and placing oil pipe two inside an oil reservoir. Simultaneously, a spherical valve core, spring two, a sealing surface, and a limiting block are used. During oil changes, spring one pushes oil pipe one and oil pipe two to squeeze the oil reservoir and empty the old oil. At this time, the limiting block on oil pipe two contacts the inner wall of one side of the oil reservoir. The operator then begins injecting lubricating oil. The lubricating oil flows into oil pipe two through the injection port and pushes the spherical valve core to open. The spherical valve core then moves away from the sealing surface and contacts the oil outlet end face on one side, sealing the outlet. During injection, the lubricating oil can only flow into the oil reservoir first, causing it to gradually expand. This, in turn, pushes oil pipe one and the push block on oil pipe one by the expanding oil reservoir. Due to the liquid pressure during injection, oil pipe two remains in place and continues to inject oil until the reservoir is filled. After the reservoir is fully expanded, oil supply pipe one and oil supply pipe two slide relative to each other to the end of their stroke. At this point, as oil supply pipe one continues to move, it drives oil supply pipe two to retract, causing the ball valve core to disengage from the oil outlet. At this time, the oil outlet opens and the raceway is normally filled with oil. This timing control ensures that the reservoir is completely filled with new oil before supplying oil to the bearing each time the oil is changed. This avoids problems such as air residue, insufficient oil storage, and inaccurate response to thermal expansion and contraction caused by an incompletely filled reservoir. The entire oil change and filling process does not require external electrical control components or additional operations and is completed automatically by a fully mechanical system. This greatly reduces the difficulty of maintenance and the risk of operation. Furthermore, this structure makes full use of the original sliding fit space without increasing the external dimensions of the bearing. While ensuring the high rigidity, high precision, and anti-tipping ability of the preloaded crossed roller bearing, it significantly improves the maintenance convenience and oil supply stability of the lubrication system.

[0016] Preferably, the oil outlet is provided with a flexible self-sealing valve flap, which cooperates with the spherical valve core.

[0017] This invention, by incorporating a flexible self-sealing valve flap at the oil outlet and cooperating with a spherical valve core, achieves a closed state for the flexible self-sealing valve flap under no pressure. This prevents lubricating oil inside the oil reservoir from leaking from the outlet to the raceway when the bearing is stationary or when the oil reservoir is not under pressure. This effectively avoids oil loss in the oil reservoir, excessive oil accumulation on the raceway surface, and fluctuations in starting torque due to increased cold resistance during frequent start-stop operations caused by abnormal lubricating oil leakage. Simultaneously, when the bearing rotates, the centrifugal force of the bearing causes the second oil supply pipe and the spherical valve core on it to retract away from the oil outlet. When the oil reservoir is discharging oil, the flexible self-sealing valve flap deforms outwards, while when the oil reservoir is absorbing oil, it deforms inwards. In these situations, the flexible self-sealing valve flap does not contact the spherical valve core, thus not affecting the normal operation of the oil reservoir. When the bearing stops, if the mounting groove and oil reservoir are located at the highest point of the bearing, the lubricating oil will leave the oil collection groove due to gravity. When the bearing temperature decreases, the oil reservoir begins to draw in oil. However, due to the loss of centrifugal force and its own gravity, the oil supply pipe and the ball valve core move towards the oil outlet and contact the flexible self-sealing valve disc that deforms towards the inside of the oil reservoir to form a blockage. At this time, the oil reservoir cannot draw in oil, thus preventing the lubricating oil from leaving the oil collection groove due to gravity and causing the oil reservoir to draw in a large amount of air during oil intake. This ensures the purity and volume stability of the lubricating oil in the oil reservoir. Furthermore, during the oil filling process, the channel will only open when the pressure of the new oil is sufficient to overcome the elastic closing force of the flexible self-sealing valve disc. This, combined with the sealing effect of the ball valve core on the oil outlet end face, makes the timing control of the oil reservoir being filled with new oil first and then supplying oil to the raceway more precise and reliable, thereby comprehensively improving the sealing safety and leak prevention capability of the lubrication system.

[0018] Preferably, a sealing ring is fixedly connected to one end of the oil pipeline, and the sealing ring is in contact with the end face of the oil injection port.

[0019] This invention achieves a reliable seal by fixing a sealing ring to one end of the oil supply pipe and ensuring that the sealing ring contacts the end face of the oil inlet. When the sealing cap is closed, the sealing ring is pressed tightly against the end face of the oil inlet, effectively preventing gas inside the pressure chamber from leaking out through the sliding fit gap between the oil inlet and the oil supply pipe. This ensures that the internal gas volume of the pressure chamber expands or contracts precisely with temperature changes, thus guaranteeing an accurate linear relationship between the compressive force on the oil reservoir and temperature changes. This avoids delayed response to thermal expansion and contraction or insufficient driving force caused by gas leakage. This ensures that the timing and quantity of oil supply in the adaptive lubrication system are always precise and reliable. Simultaneously, the sealing ring remains in contact with the inner wall of the oil inlet during the sliding of the oil supply pipe, without affecting the normal sliding stroke of the oil supply pipe. It also automatically enhances the sealing contact stress when the pressure fluctuates inside the pressure chamber, forming a pressure-assisted sealing effect. This effectively blocks external dust, moisture, and contaminants from entering the pressure chamber through the oil inlet, preventing contamination and deterioration of the oil reservoir and lubricating medium. This significantly improves the adaptability and lifespan of the humanoid robot's joint bearings in harsh environments such as dusty and humid conditions.

[0020] Preferably, the inner wall of the pressure chamber is provided with multiple rows of heat-conducting fins.

[0021] This invention significantly increases the heat exchange area between the gas inside the pressure chamber and the outer ring of the bearing by setting multiple rows of heat-conducting fins on the inner wall of the pressure chamber. This allows the heat generated during bearing operation to be transferred to the gas inside the pressure chamber more quickly and fully through the heat-conducting fins, thereby significantly shortening the gas's response time to temperature changes and ensuring that the gas volume changes more sensitively and promptly with temperature fluctuations. At the same time, the multiple rows of heat-conducting fins form an orderly flow guiding structure inside the pressure chamber, which promotes the convection circulation of the gas inside the pressure chamber, making the internal temperature distribution of the gas more uniform. This avoids problems such as uneven thermal expansion or compression lag caused by local temperature differences, thereby improving the consistency of the driving force and the stability of oil supply when the gas compresses the oil reservoir.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention, by creating an installation groove on the outer ring of the bearing and incorporating an oil reservoir, allows the gas inside the pressure chamber to expand and compress the oil reservoir when the temperature rises, thereby squeezing out the lubricating oil. Conversely, when the temperature drops, the opposite occurs. This not only avoids the problem of excessive oil supply causing additional resistance due to roller agitation at low speeds and low temperatures, but also avoids the problem of insufficient oil supply at high speeds and high temperatures. Furthermore, this structural design fully meets the compact installation space requirements of preloaded crossed roller bearings, is simple in structure, requires no additional external lubrication devices or increased bearing volume, and is highly adaptable to the confined space of robot joints.

[0023] 2. This invention provides a corrugated shell on the side of the oil reservoir and a rectangular frame. The corrugated shell uses its corrugated tubular telescopic guiding characteristics to provide precise axial constraint for the oil reservoir, ensuring that it expands and contracts regularly along the direction perpendicular to the raceway. This effectively prevents lateral torsion, radial offset, or sliding misalignment caused by high-frequency vibration, impact loads, and centrifugal force. The rectangular frame slides in the mounting groove as a rigid support component, enhancing the structural strength and support stability of the back side of the oil reservoir, ensuring uniform stress distribution and avoiding local stress concentration. This ensures smooth deformation of the oil reservoir without increasing the external space.

[0024] 3. This invention creates an annular arc groove on the outer ring of the bearing and connects it with an oil collection groove and an oil outlet. When the bearing is running at high speed, the lubricating oil is concentrated on the raceway surface by centrifugal force and accumulates in the annular arc groove to form a local enrichment area. The lubricating oil then flows into the oil collection groove through the annular arc groove, ensuring that the oil outlet is always submerged in the lubricating oil. This ensures that the oil reservoir can stably absorb a sufficient amount of pure lubricating oil without sucking in air during the thermal expansion and contraction cycle, greatly improving the oil supply continuity and cycle reliability of the adaptive lubrication system. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the preloaded cross roller humanoid robot bearing of the present invention; Figure 2 for Figure 1 A partial sectional view of the outer ring of the intermediate bearing; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 for Figure 3 Partial cross-sectional view of the central oil storage bladder; Figure 5 A cross-sectional view of a preloaded cross roller humanoid robot bearing; Figure 6 for Figure 5 Enlarged view at point B in the middle; Figure 7 for Figure 6 Enlarged view of point C in the middle.

[0026] In the diagram: 1. Inner ring of bearing; 2. Outer ring of bearing; 3. Raceway; 4. Roller; 5. Oil inlet; 6. Sealing cap; 7. Mounting groove; 8. Oil reservoir; 9. Oil outlet; 10. Corrugated housing; 11. Rectangular frame; 12. Annular arc groove; 13. Oil collection groove; 14. Oil supply pipe one; 15. Push block; 16. Spring one; 17. Oil supply pipe two; 18. Spherical valve core; 19. Spring two; 20. Sealing surface; 21. Limiting block; 22. Flexible self-sealing valve disc; 23. Sealing ring; 24. Heat-conducting fins; 25. Pressure chamber. Detailed Implementation

[0027] This invention provides a preloaded crossed roller humanoid robot bearing, the technical solution of which is as follows: Please see Figures 1 to 7 A preloaded cross-roller humanoid robot bearing includes an inner ring 1 and an outer ring 2. Raceways 3 are formed on both the inner and outer rings 1 and 2. Rollers 4 are mounted on the raceways 3. An oil inlet 5 is formed on the outer ring 2, and a sealing cap 6 is provided on the oil inlet 5. An installation groove 7 is formed on the outer ring 2, and an oil reservoir 8 is disposed inside the installation groove 7. The oil reservoir 8 is fixedly connected to the plane of the installation groove 7 near the raceway 3. A pressure chamber 25 is formed on the outer ring 2 and communicates with the installation groove 7. An oil outlet 9 is formed on the oil reservoir 8, connecting the interior of the oil reservoir 8 to the raceway 3. A corrugated shell 10 is provided on the side of the oil reservoir 8. A rectangular frame 11 is slidably connected inside the installation groove 7, and the side of the oil reservoir 8 away from the raceway 3 is fixedly connected to the rectangular frame 11.

[0028] Please see Figures 1 to 7 An annular groove 12 is formed on the outer ring 2 of the bearing, and an oil collecting groove 13 is formed on the outer ring 2 of the bearing. The oil collecting groove 13 is connected to the oil outlet 9. The depth of the annular groove 12 is 2mm. An oil supply pipe 14 is provided on the oil filling port 5. One end of the oil supply pipe 14 extends into the oil reservoir 8. The oil supply pipe 14 is slidably connected to the oil filling port 5. The sealing cap 6 is threadedly connected to the oil supply pipe 14. A push block 15 is provided on the oil supply pipe 14. A spring 16 is provided between the push block 15 and the inner wall of the outer ring 2 of the bearing. The push block 15 contacts the rectangular frame 11. An oil supply pipe 2 slidably connects to the oil supply pipe 14 on the coaxial side. The oil supply pipe 2 17 is located in the reservoir. Inside the oil sac 8, a spherical valve core 18 is provided at one end of the second oil supply pipe 17, and a spring 19 is provided between the spherical valve core 18 and the second oil supply pipe 17. A sealing surface 20 is provided at one end of the second oil supply pipe 17, and the spherical valve core 18 and the sealing surface 20 cooperate with each other. A limit block 21 is fixedly connected to one end of the second oil supply pipe 17. A flexible self-sealing valve flap 22 is provided on the oil outlet 9, and the flexible self-sealing valve flap 22 cooperates with the spherical valve core 18. A sealing ring 23 is fixedly connected to one end of the first oil supply pipe 14, and the sealing ring 23 contacts the end face of the oil injection port 5. Multiple rows of heat-conducting fins 24 are provided on the inner wall of the pressure chamber 25.

[0029] Please see Figures 1 to 7 The working process of a preloaded cross roller humanoid robot bearing is as follows: In the initial assembly state, the sealing cap 6 fixes the oil supply pipe 14 to the oil inlet 5 through the threaded connection. The oil supply pipe 14 drives the push block 15 to compress the spring 16, causing the spring 16 to store elastic potential energy. At the same time, the sealing ring 23 on the oil supply pipe 14 is pressed against the end face of the oil inlet 5 to form a reliable seal. The pressure chamber 25 is filled with a certain amount of gas, and the oil reservoir 8 stores a sufficient amount of lubricating oil. The flexible self-sealing valve disc 22 on the oil outlet 9 remains closed under no pressure. The ball valve core 18, under the action of the spring 29, cooperates with the sealing surface 20 on the oil supply pipe 27 to maintain the initial position.

[0030] When the humanoid robot's joint bearings begin normal operation, the inner ring 1 and outer ring 2 of the bearing rotate relative to each other. As the bearing's operating load and speed increase, the temperature of the outer ring 2 gradually rises. Heat is transferred from the outer ring 2 to the inner wall of the pressure chamber 25. The multiple rows of heat-conducting fins 24 on the inner wall of the pressure chamber 25 significantly increase the heat exchange area, allowing heat to be transferred more quickly and fully to the gas inside the pressure chamber 25. The gas expands due to heat, increasing its volume. This expansion pushes the rectangular frame 11 to slide along the inner wall of the mounting groove 7. The rectangular frame 11 drives the oil reservoir 8, which is fixedly connected to it, to move from the side away from the raceway 3 towards the side closer to the raceway 3. Simultaneously, the corrugated shell 10 on the side of the oil reservoir 8 utilizes its bellows-like expansion and contraction guiding characteristics to constrain the oil reservoir 8 to regularly contract in a direction perpendicular to the raceway 3. After being compressed, the internal pressure of the oil reservoir 8 increases, and lubricating oil flows out through the oil outlet 9 and pushes open the flexible self-sealing valve 22, allowing lubricating oil to flow out. The lubricating oil enters the oil collection groove 13 on the outer ring 2 of the bearing through the oil outlet 9, and then flows through the oil collection groove 13 to the annular arc groove 12 on the outer ring 2 of the bearing. Finally, the lubricating oil is distributed from the annular arc groove 12 to the raceway 3 to lubricate the rollers 4. When the bearing load decreases or the temperature gradually decreases after the machine stops, the gas inside the pressure chamber 25 contracts, and the rectangular frame 11 drives the oil reservoir 8 to move away from the raceway 3. A negative pressure is generated inside the oil reservoir 8, and the flexible self-sealing valve 22 deforms inward towards the oil reservoir 8. The lubricating oil is collected in the oil collection groove 13 through the annular arc groove 12 and then sucked back into the oil reservoir 8 through the oil outlet 9. Since the depth of the annular arc groove 12 is 2mm and the structure of the annular arc groove 12 and the oil collection groove 13 are connected, the oil outlet 9 is always submerged in lubricating oil. This ensures that the oil reservoir 8 can always absorb a sufficient amount of liquid lubricating oil without sucking in air when absorbing oil, thus completing a complete thermal expansion and contraction adaptive lubrication cycle.

[0031] When the bearing is operating at high speed, the lubricating oil accumulates and adheres to the surface of the raceway 3 of the outer ring 2 due to centrifugal force. The annular groove 12 captures and traps the lubricating oil that is scattered along the circumference of the raceway 3, forming a localized enrichment area within the annular groove 12. The oil then accumulates in the oil collection groove 13, ensuring that the oil outlet 9 is always submerged in lubricating oil. Simultaneously, the centrifugal force generated during bearing operation causes the second oil supply pipe 17 and the ball valve core 18 on the second oil supply pipe 17 to retract away from the oil outlet 9. When the oil reservoir 8 is compressed by gas expansion, the flexible self-sealing valve 22 deforms and opens outward from the oil reservoir 8, allowing the lubricating oil to flow out smoothly. When the oil reservoir 8 contracts to draw in oil, the flexible self-sealing valve 22... The deformation of the oil reservoir 8 into the interior allows lubricating oil to be smoothly drawn in. At this time, the flexible self-sealing valve disc 22 does not contact the ball valve core 18, and does not affect the normal operation of the oil reservoir 8. When the bearing stops running and the mounting groove 7 and the oil reservoir 8 are located at the highest point of the bearing, the lubricating oil leaves the oil collection groove 13 due to gravity. When the bearing temperature drops and the oil reservoir 8 begins to draw in oil, due to the loss of centrifugal force and the influence of its own gravity, the oil delivery pipe 17, together with the ball valve core 18, moves towards the oil outlet 9. The ball valve core 18 and the flexible self-sealing valve disc 22, which deforms towards the interior of the oil reservoir 8, come into contact with each other to form a blockage. At this time, the oil reservoir 8 cannot draw in oil, thus avoiding the oil reservoir 8 from drawing in a large amount of air due to the lubricating oil leaving the oil collection groove 13 due to gravity.

[0032] When the bearing needs to have its lubricating oil changed after a certain period of use, first unscrew the sealing cap 6. The oil supply pipe 14 loses the threaded connection and limiting constraint of the sealing cap 6. Spring 16 releases its elastic potential energy from its compressed state and pushes the oil supply pipe 14. The oil supply pipe 14 drives the push block 15 to move towards the oil reservoir 8. The push block 15 transmits the thrust to the rectangular frame 11 through contact with it, further compressing the oil reservoir 8. Simultaneously, the oil supply pipe 14 drives the coaxially slidingly connected oil supply pipe 17 to move together. The limiting block 21 on the oil supply pipe 17 moves with the oil supply pipe 17 until it contacts the inner wall of one side of the oil reservoir 8. The oil reservoir 8 then... During the compression process, the old lubricating oil stored inside is discharged into the raceway 3 through the oil outlet 9, the oil collection groove 13, and the annular arc groove 12, completing the forced emptying of the old lubricating oil. Then, the staff injects new lubricating oil through the oil inlet 5. The new lubricating oil flows into the first oil supply pipe 14 through the oil inlet 5 and then into the second oil supply pipe 17. The new lubricating oil pushes the ball valve core 18 on the second oil supply pipe 17 to move against the force of the second spring 19. The ball valve core 18 leaves the sealing surface 20 and moves to contact the end face of the oil outlet 9, so that the new lubricating oil cannot flow out from the oil outlet 9. The new lubricating oil is forced to flow into the oil reservoir 8. The oil reservoir 8 gradually expands and pushes the torque. The frame 11, push block 15, and oil supply pipe 14 gradually retract against the elastic force of spring 16. At this time, oil supply pipe 14 and oil supply pipe 2 17 slide relative to each other on the same axis. However, oil supply pipe 2 17 remains in place due to the pressure of the new lubricating oil and continues to inject oil into the oil reservoir 8. After the oil reservoir 8 is fully filled by the new lubricating oil, the relative sliding between oil supply pipe 14 and oil supply pipe 2 17 reaches the end of its stroke. At this time, when oil supply pipe 14 continues to retract, it drives oil supply pipe 2 17 to retract as well. The retraction of oil supply pipe 2 17 causes the ball valve core 18 to disengage from the end face of the oil outlet 9. At the same time, the pressure of the new lubricating oil overcomes the flexible self-sealing valve. The elastic closing force of the flap 22 causes it to open, and the oil outlet 9 is fully opened. At this time, the newly injected lubricating oil flows out through the oil outlet 9 to the oil collection groove 13 and the annular arc groove 12 and finally enters the raceway 3, completing the oil filling of the bearing raceway 3. After the new lubricating oil fills the raceway 3, tighten the sealing cap 6. The sealing cap 6 drives the oil supply pipe 14 to return to its original position through the threaded connection and compresses the spring 16 to restore its elastic potential energy. The push block 15 returns with the oil supply pipe 14 to release the pressure on the rectangular frame 11. At the same time, the sealing ring 23 is pressed against the end face of the oil inlet 5 when the sealing cap 6 is closed to form a reliable seal. This completes the entire oil change and oil filling operation process.

[0033] The specific embodiment of the present invention has been described in detail above with reference to the accompanying drawings, but the present invention is not limited to the embodiments described above. For those skilled in the art, various changes, modifications, substitutions, and variations made to these embodiments without departing from the principles and ideas of the present invention should still fall within the protection scope of the present invention.

Claims

1. A preloaded cross-roller humanoid robot bearing, comprising an inner bearing ring (1) and an outer bearing ring (2), wherein raceways (3) are provided on the inner bearing ring (1) and the outer bearing ring (2), rollers (4) are provided on the raceways (3), and an oil inlet (5) is provided on the outer bearing ring (2), wherein a sealing cap (6) is provided on the oil inlet (5), characterized in that, The bearing outer ring (2) is provided with an installation groove (7), and an oil reservoir (8) is provided inside the installation groove (7). The oil reservoir (8) is fixedly connected to the plane of the installation groove (7) near the raceway (3). The bearing outer ring (2) is provided with a pressure chamber (25), which is connected to the installation groove (7). The oil reservoir (8) is provided with an oil outlet (9), which connects the inside of the oil reservoir (8) to the raceway (3).

2. The preloaded cross-roller humanoid robot bearing according to claim 1, characterized in that, The oil reservoir (8) has a pleated shell (10) on its side, and a rectangular frame (11) is slidably connected inside the mounting groove (7). The side of the oil reservoir (8) away from the raceway (3) is fixedly connected to the rectangular frame (11).

3. A preloaded cross-roller humanoid robot bearing according to claim 2, characterized in that, The outer ring (2) of the bearing is provided with an annular arc groove (12) and an oil collection groove (13) is provided on the outer ring (2). The oil collection groove (13) is connected to the oil outlet (9). The depth of the annular arc groove (12) is A, 1mm≤A≤2mm.

4. A preloaded cross-roller humanoid robot bearing according to claim 2, characterized in that, An oil supply pipe (14) is provided on the oil inlet (5). One end of the oil supply pipe (14) extends into the oil reservoir (8). The oil supply pipe (14) is slidably connected to the oil inlet (5). The sealing cap (6) is threadedly connected to the oil supply pipe (14). A push block (15) is provided on the oil supply pipe (14). A spring (16) is provided between the push block (15) and the inner wall of the outer ring (2) of the bearing. The push block (15) contacts the rectangular frame (11).

5. A preloaded cross-roller humanoid robot bearing according to claim 4, characterized in that, Oil pipe two (17) is coaxially slidably connected to oil pipe one (14). Oil pipe two (17) is located inside oil reservoir (8). A ball valve core (18) is provided at one end of oil pipe two (17). A spring two (19) is provided between the ball valve core (18) and oil pipe two (17). A sealing surface (20) is provided at one end of oil pipe two (17). The ball valve core (18) and the sealing surface (20) cooperate with each other. A limit block (21) is fixedly connected to one end of oil pipe two (17).

6. A preloaded cross-roller humanoid robot bearing according to claim 5, characterized in that, The oil outlet (9) is provided with a flexible self-sealing valve flap (22), which cooperates with the spherical valve core (18).

7. A preloaded cross-roller humanoid robot bearing according to claim 5, characterized in that, A sealing ring (23) is fixedly connected to one end of the oil pipeline (14), and the sealing ring (23) is in contact with the end face of the oil inlet (5).

8. A preloaded cross-roller humanoid robot bearing according to claim 1, characterized in that, Multiple rows of heat-conducting fins (24) are provided on the inner wall of the pressure chamber (25).

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