Bearing retainer and ball bearing

Abstract

The invention provides a bearing retainer and a ball bearing, and belongs to the field of bearings. The bearing retainer comprises a retainer body and a pocket formed in the retainer body, the pocket is defined by three arc surfaces which are equal in length and radius and protrude outwards, when a ball is located in the center of the pocket during use, the minimum gap between the three arc surfaces and the ball is a pocket gap, and the radius of the arc surfaces, the radius of the ball and the pocket gap meet the requirement that the diameter of the pocket is smaller than that of the ball. And normal contact forces generated on the two arc surfaces are vertically orthogonal when the balls are in contact with any two arc surfaces in the pockets at the same time. The ball bearing comprises the bearing retainer. The orthogonal three-petal circular pockets are formed in the bearing retainer, so that the frictional wear condition of the contact interface of the inner walls of the pockets is improved, the overall friction torque of the ball bearing is reduced, the service life of the ball bearing is prolonged, and the reliability of the ball bearing is improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of bearings, in particular to a bearing retainer and a ball bearing. BACKGROUND

[0002] To ensure the normal operation of the ball bearing and prolong the service life of the ball bearing, the ball bearing needs to be regularly supplemented with lubricant during use. However, in some cases, it is inconvenient to supplement the ball bearing with lubricant in a timely manner due to space conditions and other factors, for example, angular contact ball bearings used in space vehicles momentum wheels. These ball bearings often work in an oil-starved state, at which time the friction and wear of the contact interface between the ball and the pocket on the retainer will intensify, thereby increasing the overall friction torque of the ball bearing. With continuous wear, the performance of the ball bearing will continue to deteriorate, eventually leading to failure of the ball bearing.

[0003] The pockets on the retainers of common ball bearings are generally circular in shape. Related research shows that during high-speed rotation of the ball bearing, the ball will move irregularly in all directions in the pocket due to complex motion and force conditions. Moreover, when the ball contacts the inner wall of the circular pocket, there is only one contact point, the stability of the ball during operation is poor, and the probability of collision and friction between the ball and the inner wall of the pocket is high, accelerating the friction and wear of the ball and the inner wall of the pocket, which also results in a larger overall friction torque of the ball bearing.

[0004] To solve this technical problem, some products have designed the pockets to be right-angled rhombic, for example, the main shaft bearing for tight machine tools disclosed in the Chinese Utility Model Patent Application with the publication number CN208397132U. The pockets of the bearing retainer are right-angled rhombic pockets, and when the ball contacts the inner wall of the pocket, there are at most two contact points. During operation, the pocket can provide more constraints on the ball, improving the stability of the ball and thereby reducing the probability of collision between the ball and the inner wall of the pocket. However, due to the small contact area between the spherical surface of the ball and the plane of the inner wall of the pocket, stress concentration is likely to occur at the position where the inner wall surface of the right-angled rhombic pocket contacts the ball, thereby producing stronger local scraping and local fatigue wear when used in an oil-starved state, and thereby resulting in a larger friction torque. Similarly, the square pockets of the angular contact ball bearing retainer, the retainer injection molding device, and the angular contact ball bearing disclosed in the Chinese Invention Patent Application with the publication number CN118309727A also have the problem of local wear due to large local stress.

[0005] Based on the current technical development and usage requirements, it is of great significance to develop a ball bearing that can reduce the friction and wear of the contact interface between the pocket and the ball and reduce the friction torque of the bearing in an oil-starved state, in order to improve the life and reliability of structures such as space momentum wheels. SUMMARY

[0006] The bearing retainer aims to solve the technical problem of serious friction and wear between the ball and the inner wall of the pocket in the prior art.

[0007] Another object of the present application is to provide a ball bearing to solve the above technical problems.

[0008] To achieve the above object, the technical scheme of the bearing retainer provided by the present application is as follows:

[0009] A bearing retainer comprises a retainer body and pockets arranged on the retainer body, the pockets are surrounded by three circular arc surfaces with equal length, equal radius and convexity, when the ball is located at the center of the pocket, the minimum gap between the three circular arc surfaces and the ball is pocket gap , the circular arc surface radius , the ball radius and the pocket gap satisfy , so that the normal contact forces generated on the two circular arc surfaces are perpendicular and orthogonal when the ball contacts with any two circular arc surfaces in the pocket.

[0010] As a further improvement, the intersection line of the two adjacent circular arc surfaces is the circular arc intersection line, the plane perpendicular to the retainer axis and passing through the center axis of each pocket is the pocket distribution plane, and at least part of the pockets have a circular arc intersection line on the pocket distribution plane.

[0011] As a further improvement, all the pockets have a circular arc intersection line on the pocket distribution plane, and the pocket top angles corresponding to the circular arc intersection lines on the pocket distribution plane are all directed to the same direction in the circumferential direction of the retainer.

[0012] As a further improvement, all the pockets have a circular arc intersection line on the pocket distribution plane, and in the adjacent pockets, the pocket top angles corresponding to the circular arc intersection lines on the pocket distribution plane are directed to the opposite directions in the circumferential direction of the retainer.

[0013] As a further improvement, the pockets are arranged in groups, and the directions of the pocket top angles of the pockets in the same group are different.

[0014] The bearing retainer provided by the application is an improvement over the prior art. The bearing retainer is provided with orthogonal three-petal circular pockets, so that the normal contact forces generated when the ball simultaneously contacts two circular arc surfaces in the orthogonal three-petal circular pocket are perpendicular and orthogonal, contact force decoupling is achieved, the orthogonal three-petal circular pocket has a good restraining and positioning effect on the ball, the stability of the ball is improved, the ball swing is inhibited, the probability of collision and friction between the pocket and the ball is low, and thus the friction and wear between the ball and the retainer are reduced. Meanwhile, the contact fit between the circular arc surface in the orthogonal three-petal circular pocket and the ball is high, and the contact area is larger, so that the contact stress can be dispersed, the stress concentration degree of the inner wall of the pocket is reduced, and the local wear of the contact interface is also reduced. After the friction and wear of the contact interface between the ball and the inner wall of the pocket are improved, the overall friction torque of the ball bearing using the retainer is lower, which is beneficial to improving the service life and reliability of the ball bearing.

[0015] To achieve the above-mentioned object, the technical scheme of the ball bearing provided by the application is as follows:

[0016] A ball bearing, comprising an inner ring, an outer ring, a retainer and balls located between the inner ring and the outer ring, the retainer comprising a retainer main body and pockets provided on the retainer main body, the balls being located in the pockets, the pocket being surrounded by three circular arc surfaces with equal length, equal radius and outward convexity, when the ball is located in the center of the pocket during use, the minimum gap between the ball and the three circular arc surfaces is pocket gap , the radius of the circular arc surface , the radius of the ball and the pocket gap satisfy , so that the normal contact forces generated on the two circular arc surfaces when the ball simultaneously contacts the two circular arc surfaces in the pocket are perpendicular and orthogonal.

[0017] As a further improvement, the intersection line of the two adjacent circular arc surfaces is a circular arc intersection line, the plane perpendicular to the retainer axis and passing through the center axis of each pocket is a pocket distribution plane, and at least part of the pockets have a circular arc intersection line on the pocket distribution plane.

[0018] As a further improvement, all the pockets have a circular arc intersection line on the pocket distribution plane, and the pocket top angles corresponding to the circular arc intersection lines on the pocket distribution plane all point in the same direction in the circumferential direction of the retainer.

[0019] As a further improvement, all the pockets have a circular arc intersection line on the pocket distribution plane, and in adjacent pockets, the pocket top angles corresponding to the circular arc intersection lines on the pocket distribution plane point in opposite directions in the circumferential direction of the retainer.

[0020] As a further improvement, the pockets are arranged in groups, and the pocket top angles of the pockets in the same group point in different directions.

[0021] The beneficial effect is that the bearing retainer provided by the application is an improvement on the prior art. The pockets on the bearing retainer in the ball bearing are orthogonal three-petal circular pockets, so that the normal contact force generated when the ball simultaneously contacts two circular arc surfaces in the orthogonal three-petal circular pockets is perpendicular and orthogonal, contact force decoupling is achieved, the orthogonal three-petal circular pockets play a good restraining and positioning role on the ball, the stability of the ball is improved, the ball swing is inhibited, the probability of collision and friction between the pockets and the ball is lower, thereby reducing the friction and wear between the ball and the retainer. At the same time, the contact fit between the circular arc surfaces in the orthogonal three-petal circular pockets and the ball is higher, and the contact area is larger, so that the contact stress can be dispersed, the stress concentration degree of the inner wall of the pocket is reduced, and it is also beneficial to reduce the local wear of the contact interface. After the friction and wear of the contact interface between the ball and the inner wall of the pocket are improved, the overall friction torque of the ball bearing is lower, which is beneficial to improve the service life and reliability of the ball bearing. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is a structure schematic view of the embodiment 1 of the ball bearing in the application;

[0023] Figure 2 It is a sectional view of the embodiment 1 of the ball bearing in the application;

[0024] Figure 3 It is a structure schematic view of the inner ring in the embodiment 1 of the ball bearing in the application;

[0025] Figure 4 It is a structure schematic view of the outer ring in the embodiment 1 of the ball bearing in the application;

[0026] Figure 5 It is a structure schematic view of the retainer in the embodiment 1 of the ball bearing in the application;

[0027] Figure 6 It is a state schematic view of the ball and the pocket in the embodiment 1 of the ball bearing in the application when the ball is located at the center position of the pocket;

[0028] Figure 7 It is a state schematic view of the ball and the pocket in the embodiment 1 of the ball bearing in the application when the ball simultaneously contacts two circular arc surfaces of the pocket;

[0029] Figure 8 It is a force analysis diagram between the ball and the inner wall of the pocket in the embodiment 1 of the ball bearing in the application;

[0030] Figure 9 It is a friction torque comparison diagram when the angular contact ball bearing with different shaped pockets is used.

[0031] BRIEF DESCRIPTION OF DRAWINGS

[0032] 1. Inner ring; 2. Outer ring; 3. Inner raceway; 4. Outer raceway; 5. Cage; 6. Pocket; 7. Ball bearings. Detailed Implementation

[0033] The present invention will be further described in detail below with reference to the embodiments.

[0034] Specific embodiment 1 of the ball bearing provided by the present invention:

[0035] See appendix Figure 1 and attached Figure 2 The ball bearing is specifically an angular contact ball bearing, comprising an inner ring 1, an outer ring 2, a cage 5 located between the inner ring 1 and the outer ring 2, and balls 7. See attached diagram. Figure 3 and attached Figure 4 The outer ring 2 has an inner raceway 3 on its inner side and an outer raceway 4 on its outer side. The balls 7 roll between the inner raceway 3 and the outer raceway 4. Both the inner raceway 3 and the outer raceway 4 adopt a standard curved surface raceway. The cage 5 includes a cage 5 body and pockets 6 provided on the cage 5 body. The pockets 6 are evenly spaced along the circumference of the cage 5 body and are all the same shape. Each pocket 6 is equipped with a ball 7. The cage 5 isolates each ball 7 in the circumferential direction and restricts the axial movement of each ball 7.

[0036] See appendix Figure 5 The pocket 6 is an orthogonal three-lobed circular pocket. The inner wall of the pocket 6 is formed by three convex arc surfaces of equal length and radius. The intersection of adjacent arc surfaces forms an arc intersection line, and the intersection lines of each arc surface are parallel to each other. The central axis of the pocket 6 intersects perpendicularly with the axis of the cage 5, and the intersection lines of each arc surface are simultaneously parallel to the central axis of the corresponding pocket 6.

[0037] The plane perpendicular to the axis of the cage 5 and passing through the central axis of each pocket 6 is the pocket 6 distribution plane. All pockets 6 have an arc surface intersection line located on the aforementioned pocket 6 distribution plane, and the apex angle of the pocket 6 corresponding to the arc surface intersection line located on the pocket 6 distribution plane all face the same direction in the circumferential direction of the cage 5.

[0038] See appendix Figure 6 and attached Figure 7 The radii of the three arc surfaces are all The spatial distance from the central axis of pocket 6 to the intersection of the three arc surfaces ( All are the same. When ball 7 is located at the center of pocket 6, there is a gap between the three arc surfaces and ball 7. The minimum value of this gap is the pocket gap. The gap between the three arc surfaces and the ball 7 All are equal. Radius of the arc surface Ball radius and the pocket gap satisfy , so that the normal contact forces generated on the two circular arc surfaces are perpendicular and orthogonal when the ball 7 simultaneously contacts any two circular arc surfaces in the pocket 6 、 are perpendicular and orthogonal.

[0039] The Figure 8 The geometric relationship between the ball 7 and the pocket 6 is shown in the figure, in which the three large circles are the whole circles of the circular arc surfaces in the pocket 6, Q1, Q2, and Q3 are the centers of the three large circles, and the overlapping area of the three large circles is the pocket 6. The solid small circle in the pocket 6 is the ball 7 when it contacts the side wall of the pocket 6, and O3 is the center of the ball 7 at this time. The dashed small circle is the ball 7 in the center position, and O is the center of the ball 7 at this time. F1 is the tangent point of the solid small circle and one large circle, and F2 is the tangent point of the solid small circle and another large circle. Q1, O3, and F1 are on the same straight line, and Q2, O3, and F2 are on the same straight line. P1 is the intersection point of the line Q1O and the circle where Q1 is located, and P2 is the intersection point of the line Q2O and the circle where Q2 is located. Q3, O3, and O are on the same straight line, N3 is the intersection point of the line O3O and the dashed small circle, and P3 is the intersection point of the line O3O and the circle where Q3 is located. The scale relationship in the figure is adjusted for convenience of display.

[0040] To ensure that the normal contact forces are perpendicular and orthogonal when the ball 7 simultaneously contacts any two circular arc surfaces in the pocket 6, it is necessary to ensure that According to geometric knowledge, we have

[0041] (1)

[0042] and

[0043] (2)

[0044] Solving equations (1) and (2) together, we can obtain the relationship between the radius of the circular arc surface, the radius of the ball, and the pocket gap.

[0045] Compared with the circular pocket in the prior art, the normal contact forces generated when the ball 7 simultaneously contacts two circular arc surfaces in the orthogonal three-petal circular pocket are perpendicular and orthogonal, which can achieve contact force decoupling, make the orthogonal three-petal circular pocket play a good restraining and positioning role on the ball 7, improve the stability of the ball 7, suppress the swing of the ball 7, and reduce the probability of collision and friction between the pocket 6 and the ball 7, so that the degree of friction and wear between the ball 7 and the retainer 5 is reduced when used for a long time in the oil-starved state, and the overall friction torque of the ball bearing is also lower.

[0046] ​​​Compared with the square pocket and the right-angled rhombic pocket in the prior art, the contact between the circular arc surface in the orthogonal three-petal circular pocket and the ball 7 is more closely contacted, and the contact area is larger, so that the contact stress can be dispersed, the stress concentration degree of the inner wall of the pocket 6 is reduced, and the local wear of the contact interface is reduced. After the wear between the ball 7 and the retainer 5 is improved, the friction torque of the ball bearing is also low under the condition of long-time oil starvation.

[0047] It should be noted that although theoretically the contact between the spherical surface and the circular arc surface is point contact, considering the deformation of the material when in contact, under the same conditions, the contact area between the spherical surface and the circular arc surface after extrusion deformation is larger than that between the spherical surface and the plane after extrusion deformation.

[0048] To verify the expected effect of the angular contact ball bearing with the orthogonal three-petal circular pocket under the oil-starved working condition, dynamic friction torque simulation is performed on the angular contact ball bearings with the same specifications (7004C) of the circular pocket, the square pocket and the right-angled rhombic pocket. The inner ring 1 rotates at 5000 r / min, the axial load is 60 N, and the radial load is 0 N. The simulation results are shown in FIG. 2. As can be seen, the friction torque of the angular contact ball bearing with the orthogonal three-petal circular pocket is significantly lower than that of the angular contact ball bearings with the circular pocket, the square pocket and the right-angled rhombic pocket. Figure 9

[0049] It should be noted that the above simulation still simulates the oil-starved working condition, and the change in friction torque caused by the change in pocket shape is more obvious under the oil-starved working condition. If the bearing is fully lubricated, the friction torque of the angular contact ball bearings with different shaped pockets will not differ much.

[0050] In other embodiments, the orthogonal three-petal circular pocket can also be applied to other ball bearings, such as deep groove ball bearings, to reduce friction and wear and friction torque.

[0051] In addition, the circular arc surface in the present application is not completely equivalent to the pocket side wall surface. When the pocket side wall surface has only three circular arc surfaces, the side wall surface of one side of the pocket can be regarded as the above-mentioned circular arc surface. When the pocket structure is relatively complex, such as the addition of notches, arc transition surfaces and other structures that do not affect the normal contact between the ball and the pocket side wall at the top corner of the pocket, the side wall surface of one side of the pocket is only a part of the above-mentioned circular arc surface.

[0052] Specific embodiment 2 of the ball bearing provided by the present application:

[0053] ​The embodiment is based on the embodiment 1, and differs from the embodiment 1 in that, in the embodiment, the top corners of the pockets corresponding to the intersection lines of the circular arc surfaces on the pocket distribution surface in adjacent pockets are opposite in the circumferential direction of the retainer. In this way, the characteristics of the retainer in the two opposite directions of the circumference are less different, and the force between the balls and the retainer is more uniform during use.

[0054] The specific embodiment 3 of the ball bearing provided by the application is as follows:

[0055] The embodiment is based on the embodiment 1, and differs from the embodiment 1 in that, in the embodiment, the intersection lines of the circular arc surfaces of a part of the pockets are on the pocket distribution surface, and the intersection lines of the circular arc surfaces of the remaining pockets are not on the pocket distribution surface. Specifically, the pockets whose intersection lines of the circular arc surfaces are not on the pocket distribution surface are separated by two or three pockets whose intersection lines of the circular arc surfaces are on the pocket distribution surface.

[0056] The specific embodiment 4 of the ball bearing provided by the application is as follows:

[0057] The embodiment is based on the embodiment 1, and differs from the embodiment 1 in that, in the embodiment, the intersection lines of the circular arc surfaces of all the pockets are not on the pocket distribution surface. Since the balls move in all directions when the ball bearing rotates at high speed and collide with the side walls of the pockets in all directions, the pockets can also constrain the balls well, inhibit the swing of the balls, reduce the probability of collision between the pockets and the balls, and thus reduce the friction torque of the ball bearing even if the intersection lines of the circular arc surfaces of all the pockets are not on the pocket distribution surface.

[0058] The specific embodiment 5 of the ball bearing provided by the application is as follows:

[0059] The embodiment is based on the embodiment 1, and differs from the embodiment 1 in that, in the embodiment, the pockets are arranged in groups, and the directions indicated by the top corners of the pockets in the same group are different.

[0060] Specifically, each pocket arranged in sequence in the circumferential direction in the same group is deflected by a certain angle with the center axis of the pocket as the center compared with the previous pocket, and the deflection angles of any two adjacent pockets are equal. In this way, the characteristics in all directions of the retainer as a whole are more uniform.

[0061] The specific embodiment of the bearing retainer provided by the application is as follows:

[0062] The bearing retainer is the retainer in the specific embodiments of the ball bearing described above, and will not be described again.

[0063] Finally, it should be noted that the above description is only the preferred embodiments of the present application, and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will appreciate that modifications can be made to the technical solutions described in the foregoing embodiments without departing from the spirit and principle of the present application, or some technical features thereof can be replaced by equivalent features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A bearing cage comprising a cage body and pockets provided on the cage body, characterized in that, The pocket is surrounded by three circular arc surfaces with equal length, equal radius and convexity. When the ball is in the center of the pocket, the minimum gap between the three circular arc surfaces and the ball is the pocket gap , the radius of the circular arc surface , the radius of the ball and the pocket gap satisfy , so that the normal contact forces generated on the two circular arc surfaces are perpendicular and orthogonal when the ball contacts with any two circular arc surfaces in the pocket.

2. The bearing cage of claim 1, wherein, The intersection line of the two adjacent circular arc surfaces is a circular arc intersection line, and the plane which is perpendicular to the retainer axis and passes through the center axis of each pocket is a pocket distribution plane, and at least part of the pockets have one circular arc intersection line on the pocket distribution plane.

3. The bearing cage of claim 2, wherein, All the pockets have one circular arc intersection line on the pocket distribution plane, and the pocket top angles corresponding to the circular arc intersection lines on the pocket distribution plane are all directed to the same direction in the circumferential direction of the retainer.

4. The bearing cage of claim 2 wherein, All the pockets have one circular arc intersection line on the pocket distribution plane, and in the adjacent pockets, the pocket top angles corresponding to the circular arc intersection lines on the pocket distribution plane are directed to opposite directions in the circumferential direction of the retainer.

5. The bearing cage of claim 1 wherein, The pockets are arranged in groups, and the directions of the pocket top angles of the pockets in the same group are different.

6. A ball bearing comprising an inner ring, an outer ring, a retainer and balls located between the inner ring and the outer ring, the retainer comprising a retainer main body and pockets provided on the retainer main body, the balls being located in the pockets, characterized in that, The pocket is formed by three circular arc surfaces with equal length, equal radius and convexity. When the ball is located at the center of the pocket, the minimum gap between the three circular arc surfaces and the ball is the pocket gap , the circular arc surface radius , the ball radius and the pocket gap satisfy , so that the normal contact forces generated on the two circular arc surfaces are perpendicular and orthogonal when the ball contacts with any two circular arc surfaces in the pocket.

7. The ball bearing of claim 6 wherein, The intersection line of the two adjacent circular arc surfaces is a circular arc intersection line, and the plane which is perpendicular to the retainer axis and passes through the center axis of each pocket is a pocket distribution plane, and at least part of the pockets have one circular arc intersection line on the pocket distribution plane.

8. The ball bearing of claim 7, wherein, All the pockets have one circular arc intersection line on the pocket distribution plane, and the pocket top angles corresponding to the circular arc intersection lines on the pocket distribution plane are all directed to the same direction in the circumferential direction of the retainer.

9. The ball bearing of claim 7 wherein, All the pockets have one circular arc intersection line on the pocket distribution plane, and in the adjacent pockets, the pocket top angles corresponding to the circular arc intersection lines on the pocket distribution plane are directed to opposite directions in the circumferential direction of the retainer.

10. The ball bearing of claim 6 wherein, The pockets are arranged in groups, and the directions of the pocket top angles of the pockets in the same group are different. The intersection line of the two adjacent circular arc surfaces is a circular arc intersection line, and the plane which is perpendicular to the retainer axis and passes through the center axis of each pocket is a pocket distribution plane, and at least part of the pockets have one circular arc intersection line on the pocket distribution plane. All the pockets have one circular arc intersection line on the pocket distribution plane, and the pocket top angles corresponding to the circular arc intersection lines on the pocket distribution plane are all directed to the same direction in the circumferential direction of the retainer. All the pockets have one circular arc intersection line on the pocket distribution plane, and in the adjacent pockets, the pocket top angles corresponding to the circular arc intersection lines on the pocket distribution plane are directed to opposite directions in the circumferential direction of the retainer. The pockets are arranged in groups, and the directions of the pocket top angles of the pockets in the same group are different.

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