A bearing cage

Abstract

This invention relates to the field of bearing technology, specifically to a bearing cage, comprising an upper cage, a lower cage, and multiple reinforcing ribs. The upper cage and the reinforcing ribs share an internal oil reservoir. Each reinforcing rib has trapezoidal grooves on both sides, and each trapezoidal groove contains two symmetrical adjusting plates. Each adjusting plate has a spherical groove adapted to the rolling elements on its side away from the reinforcing rib. Through the adjusting plates, spherical grooves, trapezoidal grooves, and sliding grooves and slide plates, an adaptive clearance fit can be formed between the rolling elements and the cage. When the rolling elements rotate, they cause the adjusting plates to float slightly along the sliding grooves, automatically adjusting the contact clearance according to the load. Combined with the elastic buffering effect of the first damping plate, the second damping plate, the first damping strip, and the second damping strip, flexible guidance and impact absorption of the rolling elements are achieved, avoiding the shaking impact, jamming wear problems caused by fixed clearances, and significantly improving the bearing's operational stability and service life.

Description

Technical Field

[0001] This invention relates to the field of bearing technology, and more specifically to a bearing cage. Background Technology

[0002] Bearings are core supporting components in the joint reducers of industrial robots, collaborative robots, and humanoid robots. They mainly consist of an inner ring, an outer ring, rolling elements, and a cage. As a key component of the bearing, the cage is used to evenly separate the rolling elements, prevent them from colliding and rubbing against each other, and guide them to run stably along the raceway. Its structural strength, self-lubricating properties, and smooth operation directly determine the positioning accuracy, operating noise, and service life of the robot joint. Considering the characteristics of robot joints such as low-speed heavy load, frequent start-stop, and high-precision operation, the use of lightweight, high-strength, and self-lubricating PA66 reinforced modified material to make cages has become an important development direction for high-end robot bearings.

[0003] Existing PA66 cages for robot joints are mostly one-piece window-type or wave-shaped structures. In actual use, the cage pocket and rolling elements have a fixed clearance fit without adaptive adjustment capability. Under conditions of frequent forward and reverse rotation, start-stop impact, and variable load, the clearance is prone to cause rolling element wobbling and impact due to excessive clearance, or jamming and wear due to insufficient clearance. This seriously affects the bearing's operational stability and service life. Moreover, the cage lacks an automatic lubrication supply structure that adjusts with the operating conditions. The lubricating medium is easily thrown outward and lost under centrifugal force, making it impossible to form a continuous and stable lubricating film on the contact surface between the rolling elements and the pocket. This results in the friction pair being in a state of insufficient lubrication or even dry friction for a long time, which in turn leads to premature wear, increased noise, and decreased accuracy. Summary of the Invention

[0004] In view of the above situation and to overcome the defects of the prior art, the present invention provides a bearing cage to solve the above problems.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: a bearing cage, comprising an upper cage, a lower cage, and multiple reinforcing ribs, wherein the upper cage and the multiple reinforcing ribs share an oil reservoir, each reinforcing rib has a trapezoidal groove on both sides, each trapezoidal groove has two symmetrical adjusting plates inside, each adjusting plate has a spherical groove adapted to a ball on the side away from the reinforcing rib, each trapezoidal groove has two first oil outlet holes on both inclined surfaces, and each adjusting plate has two second oil outlet holes on the surface of the adjusting plate on the side of the spherical groove.

[0006] Preferably, each trapezoidal groove has two sliding grooves on its two inclined surfaces, each sliding groove has a sliding plate slidably connected inside, and the surface of each sliding plate is fixedly connected to the surface of the adjusting plate.

[0007] Preferably, each of the first oil outlet holes is staggered with the second oil outlet hole, and one side of each of the adjusting plates is in contact with the two inclined surfaces of the trapezoidal groove.

[0008] Preferably, each of the first oil outlet holes is connected to an oil outlet pipe on its inner wall, and the end face of each oil outlet pipe is arranged in a T-shape with the inner wall of the first oil outlet hole.

[0009] Preferably, each of the oil storage tanks has two filter plates on the inner wall of the reinforcing rib, and each filter plate is located outside the liquid inlet end of the second oil outlet, and each pair of filter plates is arranged symmetrically.

[0010] Preferably, each of the filter plates is T-shaped, the convex surface of each filter plate is in contact with the inner wall of the oil storage tank, the inner wall of each oil storage tank is connected to a slide rail on the outer side of each filter plate, and the interior of each slide rail is slidably connected to the surfaces on both sides of the filter plate.

[0011] Preferably, the inner wall of each trapezoidal groove is connected to two symmetrical first damping plates, and the outer surface of each adjusting plate is fixedly connected to a second damping plate.

[0012] Preferably, a first damping strip is fixedly connected to the far side surface of each pair of adjustment plates, and two second damping strips are connected to one end of each of the two inclined surfaces of each trapezoidal groove.

[0013] Preferably, the inner wall of the oil storage tank is integrally formed with an oil injection pipe, the top of each reinforcing rib is connected to the bottom surface of the upper retainer, and the bottom of each reinforcing rib is connected to the assembly groove of the lower retainer.

[0014] The beneficial effects of this invention are as follows: 1. Through the structure of the adjustment plate, spherical groove, trapezoidal groove, slide groove and sliding plate working together, an adaptive clearance fit can be formed between the rolling element and the cage. When the rolling element is running, it drives the adjustment plate to float slightly along the slide groove, which can automatically adjust the contact clearance according to the load. Combined with the elastic buffering effect of the first damping plate, the second damping plate, the first damping strip and the second damping strip, the rolling element is flexibly guided and impact absorbed, avoiding the shaking impact, jamming and wear problems caused by fixed clearance, and significantly improving the bearing's operating stability and service life. 2. Through the interconnected structure of the oil reservoir, first oil outlet, second oil outlet, and oil outlet pipe inside the upper cage and reinforcing rib, the lubricating medium can be transported from the oil reservoir to the contact surface between the rolling element and the spherical groove by centrifugal force when the bearing is running. With the floating action of the adjusting plate, the opening of the oil outlet can be adaptively changed, realizing the on-demand supply and continuous oil supply of the lubricating medium, avoiding problems such as lubricating medium loss, dry friction with insufficient oil, early wear, and increased noise, and ensuring that a stable lubricating film is formed on the contact surface between the rolling element and the pocket. Attached Figure Description

[0015] Figure 1 This is a three-dimensional overall structural diagram of the present invention; Figure 2 This is a three-dimensional cross-sectional view of the cage structure of the present invention; Figure 3 This is a three-dimensional structural diagram of the oil storage tank of the present invention; Figure 4 This is a three-dimensional structural diagram of the reinforcing rib of the present invention; Figure 5 This is a three-dimensional structural diagram of the adjusting plate of the present invention; Figure 6 This is a three-dimensional structural diagram of the filter plate of the present invention.

[0016] In the attached diagram: 1. Upper retainer; 2. Reinforcing rib; 3. Lower retainer; 4. Spherical groove; 5. Oil injection pipe; 6. Trapezoidal groove; 7. Oil reservoir; 8. Filter plate; 9. Slide rail; 10. Second oil outlet; 11. Slide plate; 12. First damping strip; 13. Second damping plate; 14. First oil outlet; 15. Second damping strip; 16. Slide groove; 17. First damping plate; 18. Adjusting plate; 19. Oil outlet pipe. Detailed Implementation

[0017] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0018] Example: Please see Figures 1 to 6 A bearing cage includes an upper cage 1, a lower cage 3, and multiple reinforcing ribs 2. The upper cage 1 and the multiple reinforcing ribs 2 have an oil reservoir 7. Each reinforcing rib 2 has a trapezoidal groove 6 on both sides. Each trapezoidal groove 6 has two symmetrical adjusting plates 18 inside. Each adjusting plate 18 has a spherical groove 4 adapted to the ball on the side away from the reinforcing rib 2. Each trapezoidal groove 6 has two first oil outlet holes 14 on both inclined surfaces. Each adjusting plate 18 has two second oil outlet holes 10 on the surface of the adjusting plate 18 on the side of the spherical groove 4. Two sliding grooves 16 are provided on the two inclined surfaces of each trapezoidal groove 6. A sliding plate 11 is slidably connected inside each sliding groove 16. The surface of each sliding plate 11 is fixedly connected to the surface of the adjusting plate 18. Each first oil outlet 14 is staggered with the second oil outlet 10, and one side of each adjusting plate 18 is in contact with the two inclined surfaces of the trapezoidal groove 6.

[0019] Working principle: The ball fits into the curved surface of the spherical groove 4 on the adjusting plate 18. When the ball rotates, it generates a radial thrust on the adjusting plate 18. The adjusting plate 18 and the slide plate 11 are fixedly connected. This fixed connection can also be made by conventional methods such as integral molding, bonding, snap-fit, bolt connection, etc.

[0020] The sliding plate 11 and the sliding groove 16 form a sliding guide fit. This sliding fit can also adopt existing open fit methods such as guide rail sliders and guide grooves, so that the adjusting plate 18 can make a small adaptive movement along the inclined surface of the trapezoidal groove 6.

[0021] The adjusting plate 18 and the inclined surface of the trapezoidal groove 6 maintain real-time surface contact. The first oil outlet 14 and the second oil outlet 10 form an alternating opening and closing state as the adjusting plate 18 moves. In the initial state, the adjusting plate 18 blocks half of the first oil outlet 14, and the first oil outlet 14 and the second oil outlet 10 are in an alternating state, so as to realize adaptive compensation of the fit clearance between the ball and the cage, and avoid the problems of shaking impact, jamming wear and increased operating noise caused by fixed clearance.

[0022] In this scheme, the adjusting plate 18 can be any one of the arc plate, straight plate, or trapezoidal plate, and the trapezoidal groove 6 can be any one of the symmetrical trapezoidal groove, asymmetrical trapezoidal groove, or wedge groove, all of which can achieve the effect of adaptive gap adjustment.

[0023] It should be noted that adaptive clearance compensation means that the cage can automatically adjust the fit clearance between the balls and the pockets according to the load size during operation, so as to adapt to the working conditions of frequent start-stop and forward / reverse switching of the robot joint. The adjustment plate 18 and the balls form a flexible guiding fit, which does not change the original assembly relationship between the inner and outer rings of the bearing and the rolling elements, and does not affect the normal operation of the joint.

[0024] Please see Figures 1 to 6 Each first oil outlet hole 14 has an oil outlet pipe 19 connected to its inner wall, and the end face of each oil outlet pipe 19 is arranged in a T-shape with the inner wall of the first oil outlet hole 14.

[0025] Working principle: Under the action of centrifugal force, the lubricating medium flows from the oil storage tank 7 into the first oil outlet 14. The oil outlet pipe 19 and the inner wall of the first oil outlet 14 are integrally injection molded and connected. This connection can also adopt existing fixed connection methods such as plug-in, bonding, and interference fit.

[0026] The oil outlet pipe 19 and the inner wall of the first oil outlet hole 14 form a T-shaped fixed arrangement structure. The T-shaped structure can increase the flow cross section of the lubricating medium and stabilize the flow direction of the lubricating medium. The oil outlet pipe 19 changes the effective opening of the oil outlet channel as the adjusting plate 18 moves, so that the lubricating medium is stably delivered to the contact area between the ball and the spherical groove 4 according to the operation requirements, forming a continuous and uniform lubricating film in the contact area, avoiding the problems of lubricating medium loss, dry friction with insufficient oil, and early wear.

[0027] In this design, the oil outlet pipe 19 can be any of the round pipe, square pipe, or flat pipe, and the T-shaped structure can be any of the orthogonal T-shaped, oblique T-shaped, or stepped T-shaped. All of these can achieve a stable oil guiding effect and can achieve long-term self-lubrication without external oil replenishment. This does not increase the overall volume of the bearing and does not affect the assembly accuracy of the joint.

[0028] Please see Figures 1 to 6 Each oil storage tank 7 has two filter plates 8 on the inner wall of the reinforcing rib 2. Each filter plate 8 is located on the outer side of the liquid inlet end of the second oil outlet 10, and each pair of filter plates 8 are arranged symmetrically. Each filter plate 8 is T-shaped, and the convex surface of each filter plate 8 is in contact with the inner wall of the oil storage tank 7. The inner wall of each oil storage tank 7 is connected to a slide rail 9 on the outer side of each filter plate 8, and the interior of each slide rail 9 is slidably connected to the surfaces on both sides of the filter plate 8.

[0029] Working principle: After the lubricating medium flows out of the oil reservoir 7, it first passes through the filter plate 8. The filter plate 8 adopts a T-shaped structure. The convex surface of the T-shaped structure fits and is positioned against the curved surface of the inner wall of the oil reservoir 7. The filter plate 8 and the slide rail 9 are in a sliding limit fit. This fit can also adopt conventional positioning methods such as snap-fit, threaded connection, and plug-in to keep the filter plate 8 in a stable installation state in the oil reservoir 7. The filter plate 8 intercepts and filters metal debris and impurity particles in the lubricating medium, ensuring that the lubricating medium entering the first oil outlet 14 and the second oil outlet 10 is clean, avoiding problems such as oil circuit blockage, contact surface scratches, and accelerated wear caused by impurities.

[0030] The filter plate 8 can be any of the flat plate, mesh, or porous types, and the slide rail 9 can be any of the linear slide rail, arc slide rail, or dovetail slide rail types. All of these can achieve filtration and limiting effects, extend the service life of the lubrication system, reduce maintenance frequency, and not affect the normal flow of the lubrication medium.

[0031] Please see Figures 1 to 6 Each trapezoidal groove 6 has two symmetrical first damping plates 17 connected to its inner wall, and each adjusting plate 18 has a second damping plate 13 fixedly connected to its outer surface. Each pair of adjusting plates 18 has a first damping strip 12 fixedly connected to one end of each pair of adjusting plates 18, and each trapezoidal groove 6 has two second damping strips 15 connected to one end of each of the two inclined surfaces.

[0032] Working principle: When the adjusting plate 18 moves, it forms an elastic abutment with the first damping plate 17, which is integrally injection molded into the inner wall of the trapezoidal groove 6. The second damping plate 13 is fixedly connected to the adjusting plate 18. This connection can also be made by conventional methods such as bonding, snap-fitting, or hot-melt connection.

[0033] The second damping plate 13 on the outer surface of the adjusting plate 18 forms a double-layer elastic buffer fit with the first damping plate 17. The first damping strip 12 is fixedly connected to the adjusting plate 18, and the second damping strip 15 is integrally injection molded and connected to the trapezoidal groove 6. The first damping strip 12 and the second damping strip 15 form an end elastic buffer fit. The multi-layer elastic structure absorbs the impact load and vibration energy generated by the operation of the ball and the movement of the adjusting plate 18, reduces the vibration and noise of the cage operation, and improves the smoothness of the bearing operation.

[0034] The first damping plate 17 and the second damping plate 13 can be any one of the following: arc-shaped spring sheet, straight spring sheet, or wavy spring sheet. The first damping strip 12 and the second damping strip 15 can be any one of the following: round strip, square strip, or flat strip. All of these can achieve the effect of damping and noise reduction, and can control the operating noise below 35dB, meeting the requirements for use in a human-machine integrated environment.

[0035] Please see Figures 1 to 6 The inner wall of the oil storage tank 7 is integrally formed with an oil injection pipe 5. The top of each reinforcing rib 2 is connected to the bottom surface of the upper retainer 1, and the bottom of each reinforcing rib 2 is connected to the assembly groove of the lower retainer 3.

[0036] Working principle: The oil injection pipe 5 is integrally formed with the inner wall of the oil storage tank 7. This connection can also adopt conventional methods such as threaded connection, plug connection, and snap connection. The oil injection pipe 5 is used to inject lubricating medium into the oil storage tank 7.

[0037] The reinforcing rib 2 and the upper cage 1 adopt an integral injection molding structure, which improves the overall structural strength and dimensional stability of the cage. The bottom end of the reinforcing rib 2 and the assembly groove on the lower cage 3 are connected by an embedded fit. This fit can also adopt existing assembly methods such as snap-fit, thread, and transition fit, so as to realize the rapid and accurate assembly of the upper cage 1, the reinforcing rib 2 and the lower cage 3, ensuring that the overall structure of the cage is firm and the lubrication channel is reliably sealed.

[0038] The oil filling pipe 5 can be any of the straight pipe, bent pipe, or tapered pipe, and the assembly groove can be any of the rectangular groove or circular groove. All of these can achieve the filling and assembly effect. The cage forms a standard assembly relationship with the inner ring, outer ring, and rolling elements of the bearing, without changing the original structure and transmission accuracy of the reducer. It can directly replace the traditional metal cage and the ordinary PA66 cage.

[0039] In summary, during the operation of the entire equipment: During bearing operation, the balls contact the curved surface of the spherical groove 4 on the adjusting plate 18, generating radial thrust. This pushes the adjusting plate 18 to move slightly adaptively along the slide groove 16 via the slide plate 11 fixedly connected to it. This ensures that the adjusting plate 18 maintains real-time surface contact with the inclined surface of the trapezoidal groove 6. The first oil outlet 14 and the second oil outlet 10 open and close alternately with the movement of the adjusting plate 18, achieving adaptive compensation of the clearance between the balls and the cage. Simultaneously, the lubricating medium flows out from the oil reservoir 7 under centrifugal force. It first passes through the filter plate 8 to intercept and filter metal debris and impurities, then flows sequentially through the first oil outlet 14 and the T-shaped oil outlet pipe 19. The movement of the adjusting plate 18 changes the effective opening of the oil outlet channel, stably delivering the lubricating medium to the contact area between the balls and the spherical groove 4, forming a continuous and uniform lubricating film. During the movement of the adjusting plate 18, it forms an elastic contact with the first damping plate 17 and the second damping plate 13. The first damping strip 12 and the second damping strip 15 form an end elastic buffer, which together absorbs the impact and vibration energy of operation, reduces operating noise and improves the smoothness of operation. The oil injection pipe 5 continuously provides lubricating medium to the oil storage tank 7. The integrated structure of the reinforcing rib 2 and the upper cage 1 and the embedded cooperation with the lower cage 3 ensure that the overall structure is firm and the lubrication channel is sealed reliably. Finally, under the frequent start-stop, forward and reverse switching and low-speed heavy load conditions of the robot joint reducer bearing, the rolling element flexible guidance, clearance adaptive adjustment, long-term self-lubrication and vibration reduction work together to avoid the shaking impact, jamming wear, lubricating medium loss, dry friction and early wear caused by fixed clearance, and meet the requirements of high precision, low noise and long service life.

[0040] It should be noted that in the description of this invention, terms such as "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," which indicate direction or positional relationships, are based on the direction or positional relationships shown in the accompanying drawings. These are used merely for ease of description and do not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0041] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0042] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A bearing cage, comprising an upper cage (1), a lower cage (3), and a plurality of reinforcing ribs (2), characterized in that: The upper retainer (1) and the multiple reinforcing ribs (2) are provided with an oil storage groove (7). Each reinforcing rib (2) has a trapezoidal groove (6) on both sides. Each trapezoidal groove (6) has two symmetrical adjustment plates (18) inside. Each adjustment plate (18) has a spherical groove (4) adapted to the ball on the side away from the reinforcing rib (2). Each trapezoidal groove (6) has two first oil outlet holes (14) on both sides of its inclined surface. Each adjustment plate (18) has two second oil outlet holes (10) on the side of its surface located in the spherical groove (4).

2. A bearing cage according to claim 1, characterized in that: Two sliding grooves (16) are provided on both sides of each trapezoidal groove (6), and a sliding plate (11) is slidably connected inside each sliding groove (16). The surface of each sliding plate (11) is fixedly connected to the surface of the adjusting plate (18).

3. A bearing cage according to claim 1, characterized in that: Each of the first oil outlet holes (14) is staggered with the second oil outlet hole (10), and one side of each of the adjusting plates (18) is in contact with the two inclined surfaces of the trapezoidal groove (6).

4. A bearing cage according to claim 1, characterized in that: Each of the first oil outlet holes (14) has an oil outlet pipe (19) connected to its inner wall, and the end face of each oil outlet pipe (19) is arranged in a T-shape with the inner wall of the first oil outlet hole (14).

5. A bearing cage according to claim 1, characterized in that: Each of the oil storage tanks (7) has two filter plates (8) on the inner wall of the reinforcing rib (2). Each filter plate (8) is located on the outer side of the liquid inlet end of the second oil outlet (10), and each pair of filter plates (8) are arranged symmetrically.

6. A bearing cage according to claim 5, characterized in that: Each of the filter plates (8) is T-shaped, and the convex surface of each filter plate (8) is in contact with the inner wall of the oil storage tank (7). The inner wall of each oil storage tank (7) is connected to a slide rail (9) on the outer side of each filter plate (8), and the interior of each slide rail (9) is slidably connected to the surfaces on both sides of the filter plate (8).

7. A bearing cage according to claim 1, characterized in that: The inner wall of each trapezoidal groove (6) is connected to two symmetrical first damping plates (17), and the outer surface of each adjustment plate (18) is fixedly connected to a second damping plate (13).

8. A bearing cage according to claim 1, characterized in that: Each pair of adjustment plates (18) has a first damping strip (12) fixedly connected to the opposite end surface, and each trapezoidal groove (6) has two second damping strips (15) connected to one end of each of the two inclined surfaces.

9. A bearing cage according to claim 1, characterized in that: The inner wall of the oil storage tank (7) is integrally formed with an oil injection pipe (5). The top of each of the reinforcing ribs (2) is connected to the bottom surface of the upper retainer (1), and the bottom of each of the reinforcing ribs (2) is connected to the assembly groove of the lower retainer (3).

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