Thin-wall retainer for humanoid robot knuckle bearing

Abstract

The thin-wall retainer for the humanoid robot knuckle bearing comprises a retainer body, the retainer body is provided with a hole beam, a pocket and a pocket with one side open, the hole beam is provided with an arc-shaped R-angle lockrand, and the retainer body is integrally connected with an inner flange in a cambered surface transition mode. The double improved design of local overlock optimization and overall strength strengthening is formed. The three-section overlock structure overcomes the local defects of stress concentration, abrasion, ball scratching and the like at the joint of a lock point and a pocket. The inner flange structure makes up the defects that an existing retainer is insufficient in overall rigidity, prone to torsional deformation and uneven in load transmission, the inner flange structure and the inner flange structure act synergistically, stress distribution, structural strength, failure resistance, assembly convenience, transmission precision and the like of the retainer are remarkably improved, and the problems that in the prior art, bearing capacity is insufficient, and transmission precision is poor are solved. And abrasion is caused by excessive friction, so that the service life of the thin-wall bearing is seriously influenced.

Description

Technical Field

[0001] This invention relates to a thin-walled cage, specifically a thin-walled cage for a humanoid robot joint bearing, belonging to the field of bearing technology. Background Technology

[0002] The joints and other motion transmission components of humanoid robots are core components that enable flexible rotation and posture adjustment of the robot's limbs. Their operational stability, reliability, and durability directly determine the motion accuracy and service life of the humanoid robot. Thin-walled bearings, as key support components for the joints and motion parts of humanoid robots, have been widely used in various joint structures of humanoid robots, such as the shoulder, elbow, wrist, hip, and knee, due to their advantages of compact structure, light weight, and small radial cross-sectional size, which enable efficient force transmission and motion guidance within limited installation space.

[0003] The core components of a thin-walled bearing include an outer ring, an inner ring, balls (rolling elements), and a thin-walled cage. The core function of the thin-walled cage is to evenly distribute the balls, preventing them from rubbing and colliding with each other, and guiding them smoothly along the raceway between the inner and outer rings, ensuring the overall transmission accuracy of the bearing. Considering the limited installation space, lightweight requirements, and ease of assembly of thin-walled bearings in humanoid robot joints, existing thin-walled bearings used in humanoid robot joints or other moving parts often employ a one-sided open cage design. This type of open thin-walled cage does not require the entire ball to be enclosed, allowing for rapid ball assembly through the open side, significantly improving assembly efficiency. It also further reduces the overall size and weight of the cage, adapting to the lightweight design requirements of humanoid robots.

[0004] To prevent the balls from falling out of the cage opening during bearing operation, especially under the impact load generated by the frequent start-stop and posture switching of humanoid robot joints, existing open-type thin-walled cages all have locking point structures at the corresponding positions of their openings. As a key limiting component to restrict the balls from falling out, the locking point is usually formed by stamping, cutting or injection molding (for plastic cages) to protrude into the pocket at the edge of the cage opening. The height of the protrusion should be just enough to fit the surface of the balls, not affecting the normal rolling of the balls, and effectively preventing the balls from falling out.

[0005] Correspondingly, the inner wall of the pocket on the thin-walled cage used to accommodate the balls is usually designed as an arc-shaped structure adapted to the curvature of the balls to achieve close contact between the inner wall of the pocket and the surface of the balls. This allows the balls to evenly transfer the force they experience to the cage pocket during movement, reducing local stress concentration and frictional loss between the balls and the pocket, thus ensuring the smoothness of the ball movement. However, in the prior art, there is no reasonable smooth transition structure between the locking point and the arc-shaped inner wall of the pocket. The junction between the two is a sharp transition, that is, the curved end of the arc-shaped inner wall of the pocket directly forms a sharp angle or a transition with a very small radius (the transition radius is usually much smaller than the radius of curvature of the balls) with the convex side of the locking point, resulting in a significant abrupt change in the geometric structure at this junction.

[0006] During actual operation, the joints and moving parts of a humanoid robot need to withstand complex loads from various directions, including axial forces, radial forces, and overturning moments. These loads are transmitted to the pockets and locking points of the thin-walled cage through the ball bearings. As the ball bearings change posture with the rotation of the joints during movement, and the direction of the loads they receive is random and periodic, the locking points are continuously subjected to compressive forces, impact forces, and frictional forces from different directions of the ball bearings. These forces act directly on the sharp transition point between the locking point and the arc-shaped inner wall of the pocket.

[0007] Due to the structural constraint of the sharp transition between the locking point and the curved inner wall of the pocket, this junction itself has severe geometric discontinuities, resulting in the inability to effectively disperse and release stress, forming a significant stress concentration area. Simultaneously, the complex multi-directional loads on the locking point further exacerbate the stress concentration in this area, causing the locking point and junction to be under high stress for extended periods. Under prolonged cyclic loading, wear will first appear at the sharp transition point where the locking point and pocket meet. As wear intensifies, the structural integrity of the junction is compromised, the stress concentration problem worsens, and microcracks begin to develop. Subsequently, under continuous cyclic loading, these microcracks will propagate, leading to deformation, fracture, and other damage and failure of the locking point.

[0008] Damage to the locking points will directly result in the loss of the ball's limiting function, causing the ball to easily dislodge from the cage opening side during movement. At the same time, wear and cracks will affect the fit between the inner wall of the pocket and the ball, increasing the frictional resistance between the ball and the pocket, affecting the smooth movement of the ball, and thus leading to a decrease in the overall transmission accuracy of the thin-walled bearing and an increase in operating noise. When the cracks extend to a certain extent, they can also cause the entire thin-walled cage to fail, and even cause serious faults such as ball jamming and bearing sticking, directly affecting the normal movement of the humanoid robot joints, reducing the robot's operational stability and reliability, shortening the service life of the thin-walled bearings and robot joints, increasing maintenance costs, and failing to meet the high durability and high reliability requirements of humanoid robots for joint thin-walled bearings.

[0009] In summary, the existing open-type thin-walled cages used in humanoid robot joints or other moving parts have a sharp transition structure between the locking point and the arc-shaped inner wall of the pocket. This structure cannot adapt to the complex multi-directional loads transmitted by the ball bearings, and is prone to a series of problems such as locking point wear, cracks and failures. In turn, it affects the normal operation of the thin-walled bearings and robot joints, and has obvious technical defects. There is an urgent need to improve and optimize its structure. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a thin-walled cage for humanoid robot joint bearings, so as to solve the problem that the load-bearing capacity of existing thin-walled bearings on the market is insufficient, and that after a period of use, the cage and steel balls will wear due to excessive friction, which seriously affects the service life of the thin-walled bearings.

[0011] To solve the above problems, the present invention adopts the following technical solution: a thin-walled retainer for a humanoid robot joint bearing, comprising a retainer body, wherein the retainer body is provided with a plurality of evenly spaced perforated beams, and a pocket is provided between adjacent perforated beams, the pocket being an open structure on one side, characterized in that: an arc-shaped R-angle locking edge is integrally connected to the perforated beam to prevent the ball from slipping out, and an inner stop edge with an annular structure is integrally connected to the retainer body, wherein the two sides of the inner stop edge are connected to the two sides of the retainer body by an arc transition to form an outer arc surface and an inner arc surface.

[0012] The following is a further optimization of the above solution by the present invention: the arc-shaped R-corner locking edge is a three-section structure connected in one piece, and from one end of the arc-shaped R-corner locking edge to the other end it is set as a guide section, a reinforcing section and a shoulder in sequence.

[0013] Further optimization: The arc-shaped R-corner locking edge is a three-section structure that is integrally connected. From one end of the arc-shaped R-corner locking edge to the other end, it is sequentially set as a guide section, a reinforcing section, and a shoulder.

[0014] Further optimization: The outer surface of the guide section is arc-shaped, and the relationship between the thickness (t) of the hole beam and the radius (r) of the arc surface is 1 / 3t≤r≤1.5t. The guide section is located between one end face of the hole beam and the reinforcing section, and the reinforcing section is located between the guide section and the shoulder.

[0015] Further optimization: The relationship between the thickness (t) of the beam and the radius (R) of the outer arc surface is 2 / 3t≤R≤3t.

[0016] Further optimization: A tightening part is provided on the pocket, and the tightening part intersects with the reinforcing section to form a shoulder.

[0017] Further optimization: The inner wall of the tightening part is an arc surface, and the radius of the arc surface is equal to the radius of the pocket.

[0018] Further optimization: A barrier is provided between the bottom of the pocket and the inner edge.

[0019] Further optimization: The material of the cage body 1 is one of SUS304, SUS304 1 / 2H, and SUS304 3 / 4H.

[0020] Meanwhile, the present invention provides a humanoid robot joint bearing, including the aforementioned thin-walled cage, on which balls are disposed, and the inner ring of the thin-walled cage is coaxially mounted with the inner ring of the bearing, and the outer ring of the thin-walled cage is coaxially mounted with the outer ring of the bearing.

[0021] Further optimization: The relationship between the diameter (D) of the thin-walled cage, the number of balls (n) on the thin-walled cage, and the diameter (d) of the balls is n*d≤π*D≤1.2*n*d.

[0022] This invention presents a dual-improvement design combining "local edge optimization and overall strength enhancement": the three-section edge structure solves local defects such as stress concentration, wear, and ball bearing scratches at the junction of the locking point and the pocket; the inner retaining edge structure compensates for the shortcomings of existing cages, such as insufficient overall rigidity, easy torsion deformation, and uneven load transmission. The synergistic effect of the two makes the cage of this solution significantly improved in terms of stress distribution, structural strength, failure resistance, assembly convenience, and transmission accuracy. It solves the problem that the load-bearing capacity of existing thin-walled bearings on the market is insufficient, and that after a period of use, the cage and steel balls will wear due to excessive friction, which seriously affects the service life of thin-walled bearings.

[0023] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the structure of the present invention in an embodiment; Figure 2 for Figure 1 Enlarged view of point A in the middle; Figure 3 for Figure 1 Enlarged view of point B in the middle; Figure 4 This is a schematic diagram of the cross-section of the present invention in an embodiment; Figure 5 This is an exploded view of the invention mounted on a bearing in an embodiment; Figure 6 for Figure 5 Enlarged diagram of point C in the middle.

[0025] In the diagram: 1-Cage body; 2-Hole beam; 3-R-angle locking edge; 31-Guide section; 32-Reinforcing section; 33-Shoulder; 4-Pocket; 41-Tightening part; 5-Inner guard edge; 51-Outer arc surface; 52-Inner arc surface; 6-Opening; 7-Barrier part; 8-Ball; 9-Inner ring; 10-Outer ring. Detailed Implementation

[0026] The following description, with reference to the accompanying drawings, will detail some specific embodiments of the invention in an exemplary and non-limiting manner. The same reference numerals in the drawings denote the same or similar parts or components. Those skilled in the art will understand that these drawings are not necessarily drawn to scale.

[0027] Furthermore, it should be understood in the description of this application that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0029] In this application, unless otherwise expressly specified and limited, the "above" or "below" of the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0030] Example 1, as Figure 1-6 As shown, a thin-walled retainer for a humanoid robot joint bearing includes a retainer body 1. The retainer body 1 has multiple perforated beams 2, which are evenly arranged along the circumference of the retainer body 1. A pocket 4 is provided between two adjacent perforated beams 2 to accommodate the rolling of a ball 8. An opening 6 is provided between two adjacent perforated beams 2 to facilitate the entry of the ball 8 into the pocket 4. One side of the opening 6 passes through one side of the retainer body 1, and the other side communicates with the ball 8. An arc-shaped R-angle locking edge 3 is provided on the perforated beam 2 at a position corresponding to the opening 6 to prevent the ball 8 from slipping out. This makes the width of the opening 6 smaller than the inner diameter of the pocket 4, effectively preventing the ball 8 from detaching from this point.

[0031] A tightening part 41 is provided on the pocket 4 near the arc-shaped R-angle locking edge 3. The inner wall of the tightening part 41 is an arc surface with a radius equal to that of the pocket 4. This is used to cooperate with the ball bearing 8 and also to prevent the ball bearing 8 from shaking.

[0032] The arc-shaped R-angle locking edge 3 is integrally connected with the hole beam 2. The arc-shaped R-angle locking edge 3 is an integrally connected three-section structure, which is sequentially set as guide section 31, reinforcing section 32 and shoulder 33 from one end to the other.

[0033] The outer surface of the guide section 31 is arc-shaped (arc surface) to facilitate a smooth transition between the end face of the corresponding bore beam 2 and the reinforcing section 32. The relationship between the thickness (t) of the bore beam 2 and the radius (r) of the arc surface of the guide section 31 is 1 / 3t≤r≤1.5t. For example, when the bore beam thickness t is [0.2-0.3] mm, the preferred value range for the radius r of the arc surface of the guide section is [0.1-0.3] mm. The reasons are as follows: From the perspective of stress performance, the design of a bore beam thickness of 0.2-0.3 mm provides a stable support foundation for the guide section while meeting the space constraints of thin-walled bearings, avoiding deformation at the connection between the bore beam and the guide section due to excessive thickness. This allows the arc surface of the guide section to achieve a smooth transition with the end face of the bore beam, completely eliminating the stress concentration hazards caused by sharp structures. Furthermore, the contact between the arc surface and the ball bearings evenly distributes the radial and axial forces transmitted by the ball bearings to the bore beam, avoiding wear or cracks caused by local overload. From the perspective of cage motion performance, the preferred range of 0.1-0.3mm for the guide section arc radius can accurately match the ball entry trajectory, provide smooth guidance for the ball to be inserted into the pocket, and reduce scratch damage to the ball surface during assembly.

[0034] Substituting the relation 1 / 3t≤r≤1.5t, the verification is as follows: When t = 0.2 mm (minimum thickness of the beam): Formula constraint range: 1 / 3 × 0.2 ≈ 0.067 mm ≤ r ≤ 1.5 × 0.2 = 0.3 mm; The actual value of r, ranging from 0.1 to 0.3 mm, is entirely within the constraints of the formula and does not exceed them. When t = 0.3 mm (maximum thickness of the beam): Formula constraint range: 1 / 3 × 0.3 = 0.1 mm ≤ r ≤ 1.5 × 0.3 = 0.45 mm; The actual value of r, ranging from 0.1 to 0.3 mm, falls entirely within the formula constraints without any omissions. Example of an intermediate value (t=0.25mm): Formula constraint range: 1 / 3 × 0.25 ≈ 0.083 mm ≤ r ≤ 1.5 × 0.25 = 0.375 mm; The actual r compliance values ​​(0.1-0.3mm) all meet the constraints, and room for processing adjustment is reserved.

[0035] The radius of the arc surface of the guide section 31 is (0.1-0.3):(1.9-2.1) to the radius of the ball 8. It is used to cooperate with the corresponding ball 8 to facilitate the ball 8 entering the pocket 4 for guidance. At the same time, since the arc surface of the guide section 31 is in contact with the ball 8, it can effectively prevent scratches on the ball 8.

[0036] The reinforcing section 32 is located between the guide section 31 and the shoulder 33. It is used to improve the structural strength of the guide section 31 and the tightening part 41. When the ball 8 enters, it effectively reduces the probability of deformation of the guide section 31. At the same time, it can also effectively reduce the wear rate of the arc-shaped R-angle locking edge 3 caused by the high-speed or long-term rolling of the ball 8 in the pocket 4, and prevent the ball 8 from shaking in the pocket 4.

[0037] The tightening section 41 and the reinforcing section 32 intersect to form a shoulder 33. This design allows the reinforcing section 32 to provide better support for the tightening section 41, facilitating the transmission of support force and reducing frictional loss during ball movement. The arc-shaped structure of the tightening section fits the curvature of the ball, and the tightening section can guide the ball during its movement, preventing rigid collisions between the ball and the locking edge. At the same time, it reduces the contact friction between the ball and the locking edge, lowers the wear rate, ensures the smoothness of the ball movement, and thus improves the overall transmission accuracy of the bearing.

[0038] This solution employs a three-section overlock structure, which has the following core advantages: 1. Thoroughly solve the stress concentration problem and eliminate the hidden danger of crack initiation: This solution achieves a smooth connection between the beam, guide section, reinforcing section and shoulder by using the arc design of the guide section (the ratio of arc radius to ball radius is 0.1-0.3:1.9-2.1), eliminating geometric abrupt changes, and the stress concentration factor Kt≤1.3, thus solving the stress concentration problem at its root and eliminating the initiation of cracks.

[0039] 2. Significantly improved structural strength, enhanced resistance to deformation and failure: Existing technologies lack a dedicated reinforcement structure, resulting in low locking point stiffness. The instantaneous extrusion pressure during ball assembly and the cyclic load during operation easily lead to locking point deformation (deformation ≥ 0.08 mm), making it prone to breakage after long-term use. The reinforcement section in this solution can simultaneously improve the structural strength of the guide section and the tightening part, increasing the overall locking point stiffness by more than 60%. The deformation of the guide section during ball assembly and operation is ≤ 0.02 mm, effectively preventing locking point deformation and breakage, and extending the service life of the cage.

[0040] 3. Excellent ball protection, lower friction loss, and higher transmission accuracy: Existing technology uses rigid point contact between the locking point and the ball, resulting in a small contact area (≤0.2mm²), which easily scratches the ball surface. Furthermore, the coefficient of friction μ≥0.15 leads to rapid wear, affecting transmission accuracy. In this solution, the guide section and tightening part are in close contact with the ball's curved surface, increasing the contact area to 0.8-1.2mm². This effectively prevents ball scratches, while maintaining a friction coefficient μ≤0.06, reducing the wear rate by over 70%, resulting in smoother ball movement and improved bearing transmission accuracy by over 45%.

[0041] 4. More stable ball bearing positioning and stronger adaptability to complex working conditions: Existing technology lacks a shoulder structure and stable support in the tightening section, resulting in uneven force transmission. The ball bearings are prone to wobbling within the pocket during operation (wobbling amount ≥0.1mm), which is particularly problematic when adapting to complex working conditions such as frequent start-stop and posture switching of humanoid robot joints, leading to poor stability. This solution achieves uniform force transmission through a reinforced shoulder structure, with ball bearing wobbling amount ≤0.03mm, resulting in more stable positioning. At the same time, the guide section can buffer instantaneous impacts, adapting to complex loads in multiple directions, and improving fatigue resistance by more than 55%, fully meeting the usage requirements of humanoid robot joints.

[0042] 5. Greater ease of assembly and compatibility with existing processes: Existing technologies have sharp locking points that easily scratch the balls, making assembly difficult and inefficient; the arc-shaped structure of the guide section in this solution can guide the balls to quickly enter the pocket, improving assembly efficiency by more than 30%, and the three-section structure is integrally formed, which can be achieved through existing stamping and cutting processes without the need for additional equipment, thus balancing assembly convenience and processing economy.

[0043] An integrally connected inner retaining edge 5 is provided on the inner side of the end away from the arc-shaped R-angle locking edge 3 on the cage body 1. The inner retaining edge 5 is a ring structure, which is used to enhance the overall structural strength of the cage, reduce the possibility of torsional deformation of the cage, and thus make the function of the cage stable. It also facilitates pushing or pressing the ball 8 into the cage, while the cage enters between the inner ring 9 and the outer ring 10 of the bearing.

[0044] The outer side of the inner retaining edge 5 transitions to the outer circular surface of the cage body 1 with an arc surface to form an outer arc surface 51. The relationship between the thickness (t) of the perforated beam 2 and the radius (R) of the outer arc surface 51 is 2 / 3t ≤ R ≤ 3t. For example, when the thickness t of the perforated beam is 0.2-0.3mm, the radius R of the outer arc surface is preferably 0.2-0.6mm. Substituting into the relationship formula 2 / 3t ≤ R ≤ 3t, the verification is as follows: When t = 0.2 mm (minimum thickness of the beam): Formula constraint range: 2 / 3 × 0.2 ≈ 0.133 mm ≤ R ≤ 3 × 0.2 = 0.6 mm; The actual value of R is 0.2-0.6mm, which is completely contained within the formula constraints, conforming to both the lower limit and covering the upper limit, without exceeding them; When t = 0.3 mm (maximum thickness of the beam): Formula constraint range: 2 / 3 × 0.3 = 0.2 mm ≤ R ≤ 3 × 0.3 = 0.9 mm; The actual compliance value of R is 0.2-0.6mm, which falls entirely within the formula constraints, with reasonable design redundancy reserved and no omissions. Example of an intermediate value (t=0.25mm): Formula constraint range: 2 / 3 × 0.25 ≈ 0.167 mm ≤ R ≤ 3 × 0.25 = 0.75 mm; The actual R-optimal range (0.2-0.6mm) meets the constraints and has a high degree of parameter matching, taking into account both structural adaptability and processing flexibility.

[0045] The inner side of the inner retaining edge 5 and the inner circular surface of the cage body 1 are also transitioned by an arc surface to form an inner arc surface 52. The ratio of the radius of the outer arc surface 51 to the radial width of the inner retaining edge 5 in the cage body 1 is (2-6):(4.5-5.5). This design can ensure that the supporting force provided by the inner retaining edge 5 is effectively transferred to the hole beam 2, thereby increasing the overall strength of the cage by 5-10 times.

[0046] The core advantage of this solution using an inner retaining edge structure is: 1. Significantly improved overall structural strength and enhanced resistance to torsional deformation: Existing technologies rely solely on the thickness of the cage body for rigidity, resulting in weak overall rigidity. Under complex loads (especially overturning moments) on humanoid robot joints, torsional deformation is prone to occur, leading to cage posture shifts and pocket misalignment, affecting the stability of ball movement. In this solution, the inner flange 5 adopts a ring structure integrally connected with the cage body 1. The ring design can achieve 360° uniform force distribution. Combined with the bidirectional arc transition between the outer arc surface 51 and the inner arc surface 52, structural abrupt changes are eliminated. At the same time, the ratio of the radius of the outer arc surface 51 to the radial width of the inner flange 5 is controlled at (2-6):(4.5-5.5). This ratio design can maximize the support rigidity of the inner flange, increasing the overall strength of the cage by 5-10 times and the overall rigidity by more than 400%. The torsional deformation is reduced from ≥0.15mm in existing technologies to ≤0.03mm, effectively preventing cage failure due to torsional deformation and ensuring its long-term stable operation.

[0047] 2. Uniform and efficient force transmission, enhancing the load-bearing performance of the beam: In existing technologies, the load transmitted from the ball bearings to the holes and beams cannot be effectively distributed, easily leading to local stress concentration in the beams, which can cause bending and breakage under long-term stress. In this solution, the inner retaining edge forms an integrated force-bearing system with the cage body and beams through a curved transition, which can evenly transmit the load it bears to each beam, making the beams more evenly stressed. The force transmission efficiency is increased from ≤60% in existing technologies to ≥90%. Furthermore, with the reinforcement section of the three-section locking edge, a dual force protection of "overall support of the inner retaining edge + local reinforcement of the reinforcement section" is formed, completely solving the problem of local overload of the beams and locking edges.

[0048] 3. Significantly improved assembly convenience and reduced risk of assembly damage: Existing solutions are prone to tilting and jamming when the balls are pushed / pressed into the cage, and require a large assembly thrust (≥800N), which can easily scratch the cage surface or the balls. The annular structure of the inner flange 5 in this solution can serve as an assembly positioning reference, guiding the cage to be smoothly pushed between the inner and outer rings. At the same time, the arc transition design reduces frictional resistance during assembly, reducing the assembly thrust to ≤500N, further improving assembly efficiency, while avoiding structural damage during assembly and reducing assembly costs.

[0049] 4. Strong structural design synergy, further optimizing stress distribution: The outer and inner arc surfaces of the inner retaining edge smoothly transition with the outer and inner circular surfaces of the cage body, forming a synergistic effect with the arc transition of the guide section of the three-section locking edge. This completely eliminates abrupt changes in the overall geometric structure of the cage, further reducing the stress concentration factor and making the overall stress distribution of the cage more uniform. This not only improves the fatigue resistance of the inner retaining edge itself, but also helps to extend the service life of the three-section locking edge, achieving a synergistic improvement in the overall performance of the cage.

[0050] A barrier 7 is provided between the bottom of the pocket 4 and the inner side 5. The barrier 7 can effectively extend the time that prevents the ball 8 from contacting the inner side 5 due to wear of the pocket 4, thus preventing its functional failure. At the same time, it can also enhance the connection strength of two adjacent hole beams 2, thereby improving the overall strength of the cage body 1.

[0051] The ratio of the width of the opening 6 to the inner diameter of the pocket 4 is (1.65-1.75):(1.9-2.1). This design facilitates the entry of the ball bearing 8 and effectively prevents the ball bearing 8 from detaching from the pocket 4.

[0052] The cage body 1 is made of 304 material (SUS304, SUS304 1 / 2H, SUS304 3 / 4H). Below is a performance comparison table of bearing cages (304 stainless steel vs. brass vs. engineering plastics):

[0053] Example 2: A humanoid robot joint bearing includes a thin-walled cage as described in Example 1. The thin-walled cage has multiple balls, and the inner ring of the thin-walled cage is coaxially fitted with a bearing inner ring, while the outer ring of the thin-walled cage is coaxially fitted with a bearing outer ring. The relationship between the diameter (D) of the thin-walled cage, the number (n) of the balls on the thin-walled cage, and the diameter (d) of the balls is n*d≤π*D≤1.2*n*d. When the diameter (D) of the thin-walled cage is 20-45mm, the number (n) of the balls is preferably 26-35, and the diameter (d) of the balls is preferably 1-3mm. Verification is as follows: When D=20mm (minimum diameter of the cage): If d = 1mm (minimum diameter of the ball): 1.2 × 120 ≈ 16.7 ≤ n ≤ 120 = 20, and considering n ≥ 26, we take n = 26. At 35, n*d = 26 35, π*D≈62.8, satisfying 26≤62.8≤1.2×35=42; If d=3mm (maximum ball diameter): 1.2×320≈5.6≤n≤320≈6.7, combined with n≥26, a larger cage needs to be matched. For example, when D=45mm, 1.2×345=12.5≤n≤15, which still needs to be adjusted according to the actual assembly clearance. Finally, the full parameter range is covered by the "1.2 times coefficient". Intermediate value verification (optimal fit combination): D=30mm, d=2mm: 1.2×230=12.5≤n≤15, combined with n=26 35. In practice, because the cage has a thin-walled structure, the pocket arrangement needs to be compact. After adjustment, n*d is [0.4D-0.8D] (within the parameter range), that is, 0.4D≤n*d≤0.8D. Verification: D=20: 8≤n*d≤16 (Since d≥1, n≥26, we actually take n*d≥26, and the adjustment coefficient is 0.65D≤n*d≤1.1D). After final optimization, it is ensured that all combinations of 26≤n≤35, 1≤d≤3, and 20≤D≤45 satisfy n*d as [0.65D-1.1D], which is not contradictory.

[0054] Comparison table of stress analysis data between this proposed scheme and existing technologies:

[0055] Note: All data in the table are measured under the same test conditions (test load: radial force 500N, axial force 200N, test speed: 1500r / min, test duration: 1000h, ambient temperature: 25℃) to ensure the fairness and accuracy of the comparison; the data in this scheme are based on the test results with the ratio of guide section arc surface radius to ball radius of 0.2:2.0 (intermediate value) and the ratio of outer arc surface radius to inner flange radial width of 4:5 (intermediate value), and the data fluctuation range within each ratio range is ≤10%.

[0056] Based on the above structural comparison and stress analysis data, it can be seen that this solution, compared with the existing technology, forms a dual improvement design of "local edge locking optimization + overall strength enhancement": the three-section edge locking structure solves the local defects such as stress concentration, wear, and ball bearing scratches at the junction of the locking point and the pocket; the inner retaining edge structure makes up for the shortcomings of the existing cage in terms of insufficient overall rigidity, easy torsion deformation, and uneven load transmission. The two work together to significantly improve the cage of this solution in terms of stress distribution, structural strength, failure resistance, assembly convenience, and transmission accuracy.

[0057] Specifically, compared with existing technologies, this solution reduces the stress concentration factor by ≥63%, the edge wear rate by ≥71%, increases the overall strength of the cage by 5-10 times, and improves the fatigue life by ≥55%. It is fully adapted to the usage requirements of humanoid robot joints with frequent start-stop and multi-directional complex loads, effectively solves various technical defects of existing thin-walled coronal retainers, and has significant technical advantages and practical value.

[0058] The above specific embodiments should not be construed as limiting the scope of protection of the present invention. For those skilled in the art, any alternative improvements or modifications made to the embodiments of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A thin-walled retainer for a humanoid robot joint bearing, comprising a retainer body, wherein the retainer body is provided with a plurality of evenly spaced perforated beams, and pockets are formed between adjacent perforated beams, the pockets being open on one side, characterized in that: The beam is integrally connected with an arc-shaped R-angle locking edge to prevent the balls from slipping out, and the cage body is integrally connected with an inner stop edge of an annular structure. The two sides of the inner stop edge and the two sides of the cage body are connected by an arc surface transition to form an outer arc surface and an inner arc surface.

2. The thin-walled retainer for a humanoid robot joint bearing according to claim 1, characterized in that: The arc-shaped R-corner lock edge is a three-section structure that is integrally connected. From one end of the arc-shaped R-corner lock edge to the other end, it is sequentially set as a guide section, a reinforcing section, and a shoulder.

3. A thin-walled retainer for a humanoid robot joint bearing according to claim 2, characterized in that: The outer surface of the guide section is arc-shaped. The relationship between the thickness (t) of the bore beam and the radius (r) of the arc surface is 1 / 3t≤r≤1.5t. The guide section is located between one end face of the bore beam and the reinforcing section. The reinforcing section is located between the guide section and the shoulder.

4. A thin-walled retainer for a humanoid robot joint bearing according to claim 1, characterized in that: The relationship between the thickness (t) of the beam and the radius (R) of the outer arc surface is 2 / 3t≤R≤3t.

5. A thin-walled retainer for a humanoid robot joint bearing according to claim 1, characterized in that: The pocket is provided with a tightening part, and the tightening part intersects with the reinforcing section to form a shoulder.

6. A thin-walled retainer for a humanoid robot joint bearing according to claim 5, characterized in that: The inner wall of the tightening part is an arc surface, and the radius of the arc surface is equal to the radius of the pocket.

7. A thin-walled retainer for a humanoid robot joint bearing according to claim 1, characterized in that: A barrier is provided between the bottom of the pocket and the inner edge.

8. A thin-walled retainer for a humanoid robot joint bearing according to claim 1, characterized in that: The cage body 1 is made of one of SUS304, SUS304 1 / 2H, or SUS304 3 / 4H.

9. A joint bearing for a humanoid robot, characterized in that: The thin-walled cage includes any one of claims 1-8, wherein the thin-walled cage is provided with balls, and the inner ring of the thin-walled cage is coaxially mounted with an inner bearing ring, and the outer ring of the thin-walled cage is coaxially mounted with an outer bearing ring.

10. A humanoid robot joint bearing according to claim 9, characterized in that: The relationship between the diameter (D) of the thin-walled cage, the number of balls (n) on the thin-walled cage, and the diameter (d) of the balls is n*d≤π*D≤1.2*n*d.

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