Retainer for ball bearing and ball bearing

Abstract

The invention relates to a retainer for a ball bearing and the ball bearing. The retainer comprises an annular ring body and a plurality of pairs of clamping jaws extending from the ring body to the same axial direction, the plurality of pairs of clamping jaws are arranged at intervals in the circumferential direction, and a pocket used for retaining a corresponding rolling body of the ball bearing is formed between each pair of clamping jaws in the circumferential direction. Each pocket is open in an axial direction opposite the ring body and includes a retaining inner surface for contacting a respective rolling body. Wherein the cage further comprises a plurality of extended ribs, each extended rib extending around a respective pocket along a side surface of the ring body and a respective pair of jaws and protruding toward a radial side with respect to the side surface, each extended rib providing a portion of a retaining inner surface of the respective pocket, a radial extension of the respective retaining inner surface exceeds the ring body and the respective clamping jaw. The retainer and the ball bearing have improved structures.

Description

Technical Field

[0001] The present invention relates to the technical field of bearings. Specifically, the present invention relates to a cage for a ball bearing and a ball bearing including such a cage. Background Art

[0002] Ball bearings, especially deep groove ball bearings, are a common type of bearing. A ball bearing generally includes an outer ring, an inner ring, a cage, and a plurality of spherical rolling elements. The outer ring and the inner ring are coaxially arranged, and the rolling elements are rollably arranged between the outer ring and the inner ring and are held at circumferential intervals by the cage. By rolling of the rolling elements along the raceways on the outer ring and the inner ring, the ball bearing allows relative rotation between the outer ring and the inner ring.

[0003] The ball bearings in the prior art often adopt a claw-type cage. Specifically, the cage has a plurality of pairs of claws extending from the ring body toward one axial side, and pockets for holding the rolling elements are formed between each pair of claws. The pockets thus formed open toward one axial side. When installing the rolling elements, it is necessary to allow the claws to enter the pockets through the opening by elastic deformation of the claws; after the installation is completed and during operation, the claws need to have a certain strength to provide sufficient axial restraint to hold the rolling elements in the pockets. Such a cage can be made of an organic material such as polyamide, for example.

[0004] However, in some current application scenarios, such as in electric vehicles, the ball bearings need to rotate at high speeds. Since the centrifugal force is proportional to the square of the rotational speed, the cage will be subjected to a large centrifugal force at high rotational speeds, and stress concentration is likely to occur in the main load-bearing areas such as the bottom of the pockets, thus triggering a risk of fracture. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to provide an improved cage and ball bearing.

[0006] The above technical problem is solved by a cage for a ball bearing according to the present invention. The cage includes an annular ring body and multiple pairs of jaws extending from the ring body in the same axial direction. The multiple pairs of jaws are circumferentially spaced apart, and pockets for holding the corresponding rolling elements of the ball bearing are formed between the circumferences of each pair of jaws. Each pocket opens in the axial direction opposite to the ring body and includes a holding inner surface for contacting the corresponding rolling element. Among them, the cage further includes a plurality of extending ribs. Each extending rib extends around the corresponding pocket along the side surfaces of the ring body and the corresponding pair of jaws and protrudes radially outward relative to the side surfaces. Each extending rib provides a part of the holding inner surface of the corresponding pocket, so that the radial extension range of the corresponding holding inner surface exceeds that of the ring body and the corresponding jaws. By using the extending ribs extending around the pockets to meet the dimensional requirements of the holding inner surfaces of the pockets, the thickness in other areas of the ring body can be relatively reduced, thereby reducing the overall weight of the cage, improving the elasticity of the jaws, and at the same time meeting the strength requirements of the pockets.

[0007] According to a preferred embodiment of the present invention, each extending rib may include two side segments and a bottom segment that continuously extend around the corresponding pocket. The bottom segment of each extending rib is formed on the ring body and is located between the corresponding two side segments in the extending direction. The protruding height of the bottom segment of each extending rib is greater than that of the corresponding two side segments. The protruding height of the side segment of each extending rib gradually increases from the free end towards the corresponding bottom segment. The bottom segment is the main load-bearing area when holding the pocket and is prone to stress concentration. The bottom segment with a greater protruding height has higher strength, while the side segment with a smaller protruding height can improve the elasticity of the jaws, thereby facilitating the installation of the rolling elements.

[0008] According to another preferred embodiment of the present invention, the side segment of each extending rib may not extend to the free end of the corresponding pair of jaws. Thereby, the elasticity of the free end of the jaws is improved, facilitating the installation of the rolling elements.

[0009] According to another preferred embodiment of the present invention, the bottom segment of each extending rib may be flush with the axial end face of the ring body facing away from the opening direction of the pocket. Thereby, the thickness of the bottom segment is increased, further improving the strength of the bottom segment.

[0010] According to another preferred embodiment of the present invention, each extending rib may extend independently of each other and thus not be connected together. Thereby, the thickness in other areas is reduced, thus reducing the weight of the cage.

[0011] According to another preferred embodiment of the present invention, the cage may include one or more perforations in each extending rib, each perforation penetrating from the corresponding holding inner surface to the opposite surface of the corresponding extending rib in the corresponding extending rib. The perforations can reduce the contact area between the holding inner surface and the rolling elements, thereby reducing the frictional force, and at the same time can also reduce the weight of the cage.

[0012] According to another preferred embodiment of the present invention, the perforations in each extending rib may be located outside the circumferential center region of the holding inner surface of the corresponding pocket. This ensures the strength of the holding inner surface in the main load-bearing area.

[0013] According to another preferred embodiment of the present invention, the perforations in each extending rib may be symmetrically distributed about the circumferential midpoint of the holding inner surface of the corresponding pocket. This ensures the circumferential force balance of the rolling elements.

[0014] According to another preferred embodiment of the present invention, each extending rib may protrude radially outward from the ring body and the corresponding jaws. When the radial position of the holding inner surface of the pocket is fixed, the ring body in this design has a smaller radius, and thus bears less centrifugal force during rotation.

[0015] The above technical problem is also solved by a ball bearing according to the present invention. The ball bearing includes a cage having the above characteristics. Such a ball bearing thus also has the advantages corresponding to the above cage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below with reference to the accompanying drawings. The same reference numerals in the drawings represent elements with the same functions. Among them:

[0017] Figure 1 A schematic diagram showing a ball bearing with a cage installed according to an exemplary embodiment of the present invention;

[0018] Figure 2 and Figure 3 Stereoscopic views showing different perspectives of a cage according to an exemplary embodiment of the present invention; and

[0019] Figure 4 A partial schematic diagram showing a cage according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following will describe the specific embodiments of the cage and the ball bearing according to the present invention with reference to the accompanying drawings. The following detailed description and the drawings are used to exemplarily illustrate the principles of the present invention. The present invention is not limited to the described preferred embodiments, and the protection scope of the present invention is defined by the claims.

[0021] According to an embodiment of the present invention, there is provided a cage for a ball bearing and a ball bearing including such a cage.Figures 1 to 4 An exemplary embodiment of a cage according to the invention is shown.

[0022] Figure 1 1 shows a perspective view of a ball bearing equipped with a cage 30 according to an exemplary embodiment of the present invention. Figure 1 As shown, the ball bearing includes an outer ring 10, an inner ring 20, a cage 30 and a plurality of rolling elements 40. The outer ring 10 and the inner ring 20 are respectively formed as substantially cylindrical components, wherein the outer ring 10 is coaxially arranged radially outside the inner ring 20. The rolling elements 40 are spherical rolling elements. These rolling elements 40 are arranged between the outer ring 10 and the inner ring 20 in the radial direction and are distributed at intervals in the circumferential direction. These rolling elements 40 can roll along the inner surface of the outer ring 10 and the outer surface of the inner ring 20, thereby allowing the outer ring 10 and the inner ring 20 to rotate relative to each other around the central axis. The cage 30 is coaxially arranged between the outer ring 10 and the inner ring 20 in the radial direction and maintains the circumferential positions of the plurality of rolling elements 40 relative to each other.

[0023] Figure 2 and Figure 3 1 and 2 show three-dimensional views of the retaining frame 30 according to different viewing angles of the exemplary embodiment. Figure 2 and Figure 3 As shown, the retainer 30 includes an annular ring body 31 and a plurality of pairs of jaws 32 extending approximately axially from the ring body 31. When installed in a ball bearing, the annular ring body 31 is arranged approximately coaxially with the outer ring 10 and the inner ring 20. Each jaw 32 extends toward the same axial direction from the same axial side of the ring body 31. These jaws 32 are arranged at intervals along the circumference. A pocket 34 for holding the corresponding moving body 40 is formed between the circumference of each pair of jaws 32. Specifically, each pair of jaws 32 is composed of two circumferentially adjacent jaws, and the two jaws 32 can be respectively formed as roughly arc-shaped parts facing each other in the bending direction (observed in the radial direction of the ring body 31), thereby forming a circular space corresponding to the spherical contour of the rolling body 40 between the two jaws 32, i.e., a pocket 34. Each pocket 34 opens in the axial direction opposite to the ring body 31. When the clamping jaws 32 are not deformed, the circumferential dimension of the opening is smaller than the diameter of the rolling element 40, so that the rolling element 40 installed in the pocket 34 will not escape from the pocket 34 through the opening. During installation, the two clamping jaws 32 on both sides of the pocket 34 can be elastically deformed away from each other, so that the circumferential dimension of the opening becomes larger, so that the corresponding rolling element 40 can be installed in the pocket 34 through the opening. Each pocket 34 has a retaining inner surface for contacting the corresponding rolling element 40. The retaining inner surface of the pocket 34 can preferably have a profile corresponding to the shape of the rolling element 40, that is, a spherical profile.

[0024] like Figure 2 and Figure 3As shown, the cage 30 further includes a plurality of extension ribs 33. Each extension rib 33 extends along the side surfaces of the ring body 31 and a corresponding pair of jaws 32 and around the corresponding pocket 34 and protrudes radially outward or radially inward relative to the side surfaces. Here, the side surfaces refer to the surfaces of the ring body 31 and the jaws 32 facing radially outward or radially inward. The side surfaces of the ring body 31 and the jaws 32 are continuously extending surfaces, and each extension rib 33 formed on the side surfaces of the ring body 31 and the pair of jaws 32 is also a continuously extending rib. The extension ribs 33 of all the pockets 34 may be located on the same side of the ring body 31 in the radial direction, that is, all the extension ribs 33 are located radially inward of the ring body 31 and the jaws 32, or all the extension ribs 33 are located radially outward of the ring body 31 and the jaws 32. In the illustrated embodiment, all the extension ribs 33 are located radially outward of the ring body 31 and the jaws 32, so as to protrude radially outward relative to the ring body 31 and the jaws 32.

[0025] The surface of each extension rib 33 facing the inside of the corresponding pocket 34 is smoothly connected to the surface of each extension rib 33 of the ring body 31 and the jaws 32 facing the inside of the corresponding pocket 34, so as to jointly form the retaining inner surface of the pocket 34. Since a part of the retaining inner surface of each pocket 34 is provided by the corresponding extension rib 33, the radially extending range of the retaining inner surface (i.e., the length extending in the radial direction of the ring body 31) exceeds that of the ring body 31 and the corresponding jaws 32. Since the retaining inner surface usually has relatively fixed required dimensions, this means that the radial thickness of the ring body 31, which is the main body part of the cage 30, and the area of the jaws 32 where no extension ribs 33 are formed can be relatively reduced. Thereby, the overall weight of the cage 30 is reduced, and the elasticity of the jaws 32 is improved.

[0026] Preferably, each extension rib 33 extends independently of each other on the side surfaces of the ring body 31 and the jaws 32 and is not connected together. That is to say, the extension ribs 33 of different pockets 34 are separated from each other in the circumferential direction, and there is no other rib structure connecting the adjacent extension ribs 33.

[0027] As described above, in the embodiment of the present invention, the extension ribs 33 can protrude radially outward from the ring body 31 and the jaws 32, or can protrude radially inward from the ring body 31 and the jaws 32. However, as shown in the figure, the extension ribs 33 protruding radially outward are preferred. The reason is that the radial position of the retaining inner surface of the pocket 34 usually has definite requirements. In this case, when the extension ribs 33 protrude radially outward, the ring body 31 can have a relatively small radius, so the centrifugal force borne during rotation is smaller.

[0028] Each extension rib 33 extends continuously around a corresponding pocket hole 34 and can be divided in its extending direction into three interconnected segments, including two side segments 33a and a bottom segment 33b. The bottom segment 33b of each extension rib 33 is substantially formed on the ring body 31 and is located between the corresponding two side segments 33a in the extending direction. The two side segments 33a respectively extend from the circumferential two ends of the bottom segment 33b towards the free ends of the two jaws 32 located on both sides of the corresponding pocket hole 34. The bottom segment 33b and the opening of the corresponding pocket hole 34 are substantially axially opposite. When the ball bearing rotates, the circumferential region corresponding to the bottom segment 33b on the inner surface is the main load-bearing region and stress concentration region. Preferably, the overall shape of the extension rib 33 can be substantially symmetric about the circumferential midpoint of the pocket hole 34.

[0029] Figure 4 A longitudinal sectional view of the cage 30 at the midpoint of a pocket hole 34 is shown. As Figure 4 shown, preferably, the protruding height of the bottom segment 33b of each extension rib 33 can be greater than the protruding heights of the corresponding two side segments 33a. In addition, the protruding height of the side segment 33a of each extension rib 33 can also gradually increase from the free end of the side segment 33a (the end away from the bottom segment 33b) towards the corresponding bottom segment 33b. Each bottom segment 33b can have a substantially constant protruding height or can have a protruding height that gradually increases from the circumferential two ends towards the circumferential midpoint. Preferably, the protruding height at the connection between the side segment 33a and the bottom segment 33b can be continuously and smoothly transitioned. The protruding height here refers to the length by which the extension rib 33 protrudes from the side surfaces of the ring body 31 and the jaws 32 in the radial direction of the ring body 31 at a certain position in the extending direction. The extension rib 33 of this shape has higher strength in the bottom segment 33b, thereby reducing the risk of fracture. At the same time, the closer to the free end of the jaw 32, the smaller the size of the extension rib 33 and the greater the elasticity of the jaw 32, thus facilitating the installation of the rolling elements 40. Since the free end of the jaw 32 bears less load during operation, therefore, the two side segments 33a of each extension rib 33 can preferably not extend to the free ends of the corresponding pair of jaws 32. This reduces the size of the extension rib 33 and further reduces the overall weight of the cage 30.

[0030] As Figure 2 shown, in a preferred embodiment, the bottom segment 33b of each extension rib 33 can be flush with the axial end face of the ring body 31 facing away from the pocket hole opening direction. This increases the thickness of the bottom segment 33b, thereby further improving the strength of the bottom segment 33b.

[0031] In a preferred embodiment, the cage 30 includes one or more perforations 33c in each extending rib 33. Each perforation 33c extends from the corresponding holding inner surface through to the opposite surface of the corresponding extending rib 33, i.e., the side surface of the extending rib 33 facing away from the pocket 34. These perforations 33c are only formed in the region of the extending rib 33 and do not extend into the regions of the ring body 31 and the jaws 32. The perforations 33c reduce the contact area between the holding inner surface and the rolling elements 40, reduce the frictional force, and at the same time further reduce the weight of the cage 30.

[0032] The perforations 33c on each extending rib 33 can be formed either in the side section 33a, or in the bottom section 33b, or in both the side section 33a and the bottom section 33b simultaneously. Preferably, the perforations 33c formed on each extending rib 33 are located outside the circumferential central region of the holding inner surface of the corresponding pocket 34. That is to say, the perforations 33c preferably avoid the circumferential central region of the holding inner surface, thereby ensuring the structural strength of the main load-bearing region. Preferably, similar to the shape of the extending rib 33, one or more perforations 33c of each extending rib 33 can also be symmetrically distributed about the circumferential midpoint of the holding inner surface of the corresponding pocket 34.

[0033] According to an embodiment of the present invention, there is also provided a ball bearing including the above-mentioned cage 30. This ball bearing thus has the corresponding features and advantages as the above-mentioned cage 30.

[0034] In the cage and the ball bearing according to the present invention, a part of the holding inner surface for holding the rolling elements is provided by the extending ribs protruding from the ring body and the jaws, so that the overall thickness of the ring body and the jaws can be reduced, thereby reducing the overall weight of the cage. At the same time, through the dimensional arrangement of the extending ribs, the structural strength in the main load-bearing region and the stress concentration region can be specifically improved, thereby ensuring the reliability of the cage and facilitating the installation of the rolling elements. In addition, through the perforations formed on the extending ribs, the weight of the cage can be further reduced, and at the same time, the friction between the rolling elements and the holding inner surface can be reduced, thereby improving the overall efficiency of the ball bearing.

[0035] Although possible embodiments have been described exemplarily in the above description, it should be understood that there are still a large number of variations of the embodiments through combinations of all known and additionally technically conceivable technical features and embodiments. It should also be understood that the exemplary embodiments are merely an example, and such embodiments in no way limit the protection scope, application, and construction of the present invention. Through the foregoing description, more is to provide a technical guidance for those skilled in the art to transform at least one exemplary embodiment, wherein various changes can be made as long as the protection scope of the claims is not departed from, especially changes regarding the functions and structures of the components.

[0036] List of reference signs

[0037] 10 Outer ring

[0038] 20 Inner ring

[0039] 30 Cage

[0040] 31 Ring body

[0041] 32 Claw

[0042] 33 Extension rib

[0043] 33a Side section

[0044] 33b Bottom section

[0045] 33c Perforation

[0046] 34 Pocket

[0047] 40 Rolling element

Claims

1. A cage (30) for a ball bearing, comprising an annular ring body (31) and a plurality of pairs of jaws (32) extending from the ring body (31) in the same axial direction. The plurality of pairs of jaws (32) are circumferentially spaced apart, and a pocket (34) for holding a corresponding rolling element (40) of the ball bearing is formed between the circumferences of each pair of jaws (32). Each pocket (34) opens in an axial direction opposite to the ring body (31) and includes a holding inner surface for contacting the corresponding rolling element (40). Characterized in that, the cage (30) further includes a plurality of extending ribs (33). Each extending rib (33) extends around the corresponding pocket (34) along the side surfaces of the ring body (31) and the corresponding pair of jaws (32) and protrudes radially outward with respect to the side surfaces. Each extending rib (33) provides a part of the holding inner surface of the corresponding pocket (34), such that the radial extension range of the corresponding holding inner surface exceeds the ring body (31) and the corresponding jaws (32).

2. The cage (30) according to claim 1, characterized in that, Each extending rib (33) includes two side segments (33a) and a bottom segment (33b) that continuously extend around the corresponding pocket (34). The bottom segment (33b) of each extending rib (33) is formed on the ring body (31) and is located between the corresponding two side segments (33a) in the extending direction. The protruding height of the bottom segment (33b) of each extending rib (33) is greater than the protruding heights of the corresponding two side segments (33a). The protruding height of the side segment (33a) of each extending rib (33) gradually increases from the free end towards the corresponding bottom segment (33b).

3. The cage (30) according to claim 2, characterized in that, The side segment (33a) of each extending rib (33) does not extend to the free end of the corresponding pair of jaws (32).

4. The cage (30) according to claim 2, characterized in that, The bottom segment (33b) of each extending rib (33) is flush with the axial end face of the ring body (31) facing away from the pocket opening direction.

5. The cage (30) according to claim 1, characterized in that, Each extending rib (33) extends independently of each other and is not connected together.

6. The cage (30) according to claim 1, characterized in that, The cage (30) includes one or more through holes (33c) in each extending rib (33). Each through hole (33c) penetrates from the corresponding holding inner surface to the opposite surface of the corresponding extending rib (33) in the corresponding extending rib (33).

7. The cage (30) according to claim 6, characterized in that, The through hole (33c) of each extending rib (33) is located outside the circumferential center region of the holding inner surface of the corresponding pocket (34).

8. The cage (30) according to claim 1, characterized in that, The through holes (33c) of each extending rib (33) are symmetrically distributed about the circumferential midpoint of the holding inner surface of the corresponding pocket (34).

9. The cage (30) according to any one of claims 1 to 8, characterized in that, Each extending rib (33) protrudes radially outward from the ring body (31) and the corresponding jaws (32).

10. A ball bearing, characterized in that, The ball bearing includes the cage (30) according to any one of claims 1 to 9.

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