ROLLING-ELEMENT BEARING CAGE, ROLLING-ELEMENT BEARING, VEHICLE, AND METHOD FOR ASSEMBLING A ROLLING-ELEMENT BEARING CAGE

Abstract

A rolling-element bearing cage having a central axis of rotation includes a first cage ring having an axial extension and at least one snap arm disposed directly on the extension, and a second cage ring having an attachment region to which the at least one snap arm is snapped. The attachment region is located at a first distance from the central axis of rotation. A portion of each of the at least one each snap arm of the first cage ring is located at a second distance from the central axis of rotation, the second distance being less than the first distance.

Claims

1. A rolling-element bearing cage having a central axis of rotation and comprising: a first cage ring having an axial extension and at least one snap arm disposed directly on the extension, and a second cage ring having an attachment region to which the at least one snap arm is snapped, the attachment region being located at a first distance from the central axis of rotation, wherein a portion of each of the at least one each snap arm of the first cage ring is located at a second distance from the central axis of rotation, the second distance being less than the first distance.

2. The rolling-element bearing cage according to claim 1, wherein the rolling-element bearing cage includes a plurality of pockets each defined by the first cage ring and the second cage ring, wherein each of the at least one snap arm is circumferentially disposed between a pair of circumferentially adjacent ones of the plurality of pockets, and wherein each of the at least one snap arm is not circumferentially centered between the pockets of the pair of circumferentially adjacent ones of the plurality of pockets.

3. The rolling-element bearing cage according to claim 1, wherein the attachment region includes a radially outwardly facing surface.

4. The rolling-element bearing cage according to claim 1, wherein the entire attachment region is located more than the first distance from the central axis of rotation.

5. The rolling-element bearing cage according to claim 1, wherein the first cage ring and the second cage ring are identical.

6. The rolling-element bearing cage according to claim 1, wherein the second cage ring includes a snap arm, and wherein the at least one snap arm of the first cage ring and the snap arm of the second cage ring are located between a pair of circumferentially adjacent ones of the plurality of pockets

7. A ball bearing including a rolling-element bearing cage according to claim 1.

8. An electric vehicle comprising: an electric motor, and a drive shaft driven by the electric motor, wherein the drive shaft is supported by a ball bearing according to claim 7

9. The rolling-element bearing according to claim 1, wherein the portion of the at least one snap arm includes a radially outwardly facing concave surface, and wherein the attachment region includes a radially inwardly facing convex surface.

10. A method for assembling a rolling-element bearing cage, comprising: moving a first cage ring having an axial extension and at least one snap arm disposed directly on the extension axially toward a second cage ring having an attachment region such that each of the at least one snap arm is deflected radially inwards by a radially inner portion of the attachment region until the at least one snap arm is snapped to the attachment region.

11. The method of claim 9, wherein partial regions of a lateral ring that is part of the first cage ring and, in an assembled state of the rolling-element bearing cage, is disposed on an axial end of the rolling-element bearing cage, are deflected relative to other partial regions of the lateral ring at least in an axial direction of the first cage ring during a producing of the snap connection.

12. A rolling-element bearing cage with a first cage ring which includes an axial extension and at least one snap arm disposed directly on the extension and at least one second cage ring which includes at least one attachment region at which the at least one snap arm for forming a snap connection is snapped, characterized in that there is wherein there is a section extending in the axial direction of the rolling-element bearing cage in which each snap arm of the first cage ring disposed directly on the extension has a smaller distance from a central axis of the rolling bearing cage extending in the axial direction of the rolling bearing cage than the attachment region.

13. The rolling-element bearing cage according to claim 12, wherein with respect to a circumferential direction of the rolling-element bearing cage, the snap arm is disposed between two pockets disposed adjacent in the circumferential direction of the rolling-element bearing cage, and a first of the pockets is delimited by a lateral ring of the first cage ring and a lateral ring of the second cage ring and a first crosspiece of the rolling-element bearing cage and a second crosspiece of the rolling-bearing cage, wherein the second crosspiece has a greater distance from the snap arm than the first crosspiece, wherein the snap arm and/or the extension are or is disposed spaced from the first crosspiece.

14. The rolling-element bearing cage according to claim 13, wherein the snap arm and a further snap arm of the rolling-element bearing cage are disposed between two pockets, adjacent in the circumferential direction of the rolling-element bearing cage.

15. A ball bearing with a rolling-element bearing cage according to claim 12.

16. A vehicle with electric propulsion and with a rolling-element bearing according to claim 15, wherein the rolling-element bearing supports a shaft of an electric motor of the vehicle, which shaft is provided to at least contribute to the propulsion of the vehicle, or the rolling-element bearing is part of a transmission that transmits a propulsion from the electric motor to a differential of the vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] FIG. 1 is a perspective view of a first cage ring of an inventive rolling-element bearing cage according to an embodiment of the present disclosure.

[0024] FIG. 2 is a perspective view of the rolling-element bearing cage of FIG. 1.

[0025] FIG. 3 is a perspective view of a second cage ring of the rolling-element bearing cage of FIG. 1.

[0026] FIG. 4 is a perspective, axial sectional view of the rolling-element bearing cage of FIG. 1.

[0027] FIG. 5 is a schematic representation of a part of the rolling-element bearing cage of FIG. 1 with a snap arm and an attachment region immediately before a snap connection is formed.

[0028] FIG. 6 is a schematic representation of the part of the rolling-element bearing cage during the production of the snap connection.

[0029] FIG. 7 is a schematic representation of the part of the rolling-element bearing cage after the production of the snap connection.

[0030] FIG. 8 is a schematic view of a part of a second exemplary embodiment of a rolling-element bearing cage according to the present disclosure.

[0031] FIG. 9 is a perspective view of a cage ring of the rolling-element bearing cage of FIG. 8.

[0032] FIG. 10 is a perspective view of an axial section of rolling-element bearing cage of FIG. 8.

[0033] FIG. 11 is a perspective view of a second cage ring of the rolling-element bearing cage of FIG. 8.

[0034] FIG. 12 is a schematic view of a part of a third exemplary embodiment of a rolling-element bearing cage according to the present disclosure.

[0035] FIG. 13 is a perspective view of an axial section of the rolling-element bearing cage of FIG. 12.

[0036] FIG. 14 is a perspective view of a first cage ring of the rolling-element bearing cage of FIG. 12.

[0037] FIG. 15 is a perspective view of a second cage ring of the rolling-element bearing cage of FIG. 12.

[0038] FIG. 16 is a further perspective view of the second cage ring of the rolling-element bearing cage of FIG. 12.

[0039] FIG. 17 is a schematic view from radially outside onto a fourth embodiment of a rolling-element bearing cage according to the present disclosure.

DETAILED DESCRIPTION

[0040] FIG. 1 shows a perspective view of a first cage ring 12 of an inventive rolling-element bearing cage 10, which is depicted completely in FIG. 2. The cage ring 12 includes a lateral ring 40, to which an axial extension 14 connects. The extension 14 forms a part of a boundary 16 of a pocket 18 of the rolling-element bearing cage. A snap arm 20 is directly attached to the extension 14. The rolling-element bearing cage further includes a second cage ring 22 that comprises an attachment region 24 into which the snap arm 20 is snapped for forming a snap connection (FIGS. 4 and 7). The rolling-element bearing cage has a central axis 28 extending in the axial direction of the rolling-element bearing cage along which central axis 28 there is a section 26 in which each snap arm 20 of the first cage ring 12, which is disposed directly on the extension 14, has a smaller distance from the central axis 28 than the attachment region 24. More precisely, a part of the snap arm 20 that is disposed between two planes 44, 46 that each include an endpoint of the section 26 and are cut vertically from the central axis 28, has a smaller distance from the central axis 28 than the attachment region 24, which is disposed completely between the planes 44, 46 because a complete axial extension region of the attachment region 24 is the axial section 26. Furthermore, the attachment region has a surface region 32 lying outwardly with respect to a radial direction 30 of the rolling-element bearing cage of the rolling-element bearing cage (FIGS. 4 and 7).

[0041] The first cage ring 12 and the second cage ring 22 are identically formed. The second cage ring includes a recess 48 into which the snap arm 20 is introduced and snapped during a producing of the snap connection. A snap arm 34 of the second cage ring 22 is directly adjacent to the recess 48. During the producing of the snap connection, the snap arm 34 is introduced and snapped into a recess (not depicted) of the first cage ring 12; the recess is directly adjacent to the snap arm 20. The two snap arms 20, 34 are thus disposed between the pocket 18 and a pocket 36, which are disposed adjacent in the circumferential direction of the rolling-element bearing cage and are thus directly consecutive. Between all adjacent pockets of the rolling-element bearing cage, two snap arms are disposed that form a snap connection as described for the snap arm 20. All snap arms are formed identically.

[0042] In comparison to a radially outer surface of the extension 14, the snap arm 20 is disposed radially inward. A tip of the snap arm 20 forms a part of an end surface of the second cage ring 22.

[0043] In the FIGS. 5-7, the different stages are depicted of a producing of the snap connection that is ultimately realized by the snap arm 20 and the attachment region 24. At a start of a forming of the snap connection, a taper of the snap arm 20 contacts the attachment region 24 such that by a further moving of the snap arm 20 toward the attachment region 24, the snap arm 20 is deflected radially inward compare FIG. 6, in which a deformation of the snap arm is not depicted. With a still further moving of the snap arm 20 toward the attachment region 24, in comparison to the arrangement depicted in FIG. 6, the snap arm snaps radially outward and engages behind the attachment region 24. However, in this case the snap arm has a shape which permits non-destructive release of the snap connection by pulling the fastening area 24 and the snap arm 20 apart axially.

[0044] Overall, the first cage ring 12 is attached to the second cage ring 22 by a snap connection, which is realized by the individual snap connection of the individual snap arms of the rolling-element bearing cage. An assembling of the rolling-element bearing cage consists in attaching the cage ring 12 to the cage ring 22 by the snap connection. During the producing of this snap connection, the cage ring 12 is pressed against the cage ring 22 such that in comparison to an unassembled state in which the first cage ring is disposed spaced from the second cage ring, all snap arms of the first cage ring and all snap arms of the second cage ring 22 are deflected radially inward, and, with a further pressing of the cage ring 12 against the cage ring 22, snap in.

[0045] During the assembling of the rolling-element bearing cage 10, partial regions of the lateral ring 40, which is part of the first cage ring 12 and in an assembled state of the rolling-element bearing cage is disposed on an axial end 41 of the rolling-element bearing cage, are deflected during a producing of the snap connection relative to other partial regions 42 of the lateral ring 40 at least in an axial direction of the first cage ring 12. A larger deflection of the snap arms radially inward is thereby made possible. A force that is required for the producing of the snap connection thus depends on a rigidity of the lateral ring 40. The deflecting of the partial regions 38 is effected by them each performing a rotational movement.

[0046] In an installed state, the rolling-element bearing cage is part of a ball bearing. The ball bearing is in turn part of a vehicle with electric propulsion and supports there a shaft of an electric motor, which is provided to provide at least a contribution to a propulsion of the vehicle. Alternatively, the ball bearing can also be part of a transmission of the vehicle, which transmits a propulsion from the electric motor to a differential of the vehicle.

[0047] The cage ring 12 and the cage ring 22 are each configured one-piece. Each of the two cage rings can be produced in a single injection molding process, which is cost-effective, or by 3D printing. In the injection molding processes, molds without movable parts can be used, whereby a particularly cost-effective production is possible. Furthermore, after the injection molding processes, rods can be introduced into the injection molds, whereby a simple demolding is possible.

[0048] The rolling-element bearing cage can in particular be formed from polyamide 66 or polyetheretherketone. Here a reinforcing by fibers can be present, and specifically in particular a reinforcing by glass fibers and/or carbon fibers. Furthermore, the rolling-element bearing cage can also be comprised of a metallic material, such as in particular brass or aluminum. The rolling-element bearing cage can be homogeneously constructed from a single material.

[0049] Due to the fact that the two cage rings are attached to each other by snapping, a simple, fast, and cost-effective assembling of the rolling-element bearing cage is possible.

[0050] The rolling-element bearing cage is in particular robust in comparison to a one-part cage because a suitability for high rotational speeds is present. Further, when the cage is rotated, the snap arms 20,34 are forced radially outward, increasing a circumferential attachment of the snap arms and thus the cage ring 12 to the cage ring 22 by improving a frictional connection between the snap arms and the cage ring 22 through an increased force. Furthermore, during the rotation the snap connection becomes tighter.

[0051] The snap arm 20 tapers with increasing distance from the extension 14 in an alternative embodiment according to FIG. 5 (in this case, FIG. 5 is not merely schematic). This allows for easy demolding when manufactured by injection molding. During the demolding, the snap arm 20, when it is demolded curved as depicted in FIG. 5, is bent nearly straight. This is possible due to the elasticity of the rolling-element bearing material and a high casting temperature during an injection molding of the cage, but means that the degree of curvature of the snap arms is limited. The possible degree of curvature also depends on the thickness of the snap arms. The thicker the arms, the stronger they are, but the thickness limits the curvature. In the alternative embodiment according to FIG. 5, the snap arm 20 and the attachment region 24 then also configured according to an alternative embodiment have a round contact surface.

[0052] In the rolling-element bearing cage 10 there is no umbrella effect. Furthermore, the design of the rolling-element bearing cage 10 is suitable when the rolling-element bearing cage must be small, because there is no snap arm arranged on a radially outer side of the mounting portion 24, which is attached to the extension 14. Installation space is thereby saved in the radial direction.

[0053] The rolling-element bearing cage 10 is comprised of the cage rings 12, 22.

[0054] After a final assembly, the rolling-element bearing cage 10 can be part of any device in which it enables rotation at high speed. Here the rolling-element bearing cage can have comparatively small dimensions. For example, the rolling-element bearing cage can be used in a supporting of a shaft of a motor, or in special vacuum pumps.

[0055] Alternative exemplary embodiments are depicted in FIGS. 8 to 17. Essentially identical components, features, and functions are generally numbered with the same reference numbers. However, to distinguish the exemplary embodiments, the letter a or the letter b or the letter c are added to the reference numbers of the exemplary embodiments of FIGS. 8 to 17. The following description is essentially limited to the differences to the exemplary embodiment in FIG. 1 to FIG. 7, whereby reference can be made to the description of the embodiment example in FIGS. 1 to 7 with regard to components, features and functions which remain the same.

[0056] FIGS. 8 to 11 represent a second exemplary embodiment. FIG. 8 shows a view from radially outside onto the first alternative exemplary embodiment of a rolling-element bearing cage 10a. Between two circumferentially adjacent pockets 18a, 36a, only one snap arm 20a of the rolling bearing cage is arranged in each case. The snap arm 20a is part of a cage ring 12a, and is snapped in an attachment region 24a of a second cage ring 22a (FIGS. 8 and 10). The rolling-element bearing cage includes an even number of pockets. Therefore, the cage rings are identical. However, in an alternative embodiment, the rolling-element bearing cage can also include an odd number of pockets. The two exemplary embodiments are particularly advantageous for situations in which the rolling-element bearing cage is to be small, or only little space is present between two adjacent pockets 18a, 36a.

[0057] FIGS. 12 to 16 represent a third exemplary embodiment. FIG. 12 shows a radially outer view of the second alternative exemplary embodiment of a rolling-element bearing cage 10b. In each case only a single snap arm 20b of the rolling-element bearing cage is disposed between two pockets 18b, 36b adjacent in the circumferential direction (FIGS. 12 and 14). All snap arms of the rolling-element bearing cage are part of a cage ring 12b. A second cage ring 22b is free of snap arms (FIGS. 15 and 16). The present exemplary embodiment is suitable for an even number of pockets. In particular, the exemplary embodiment is particularly suitable for an odd number of pockets because in this case it is not possible to have two identical cage rings 12, 22.

[0058] FIG. 17 shows a radially outer view of a fourth embodiment of a rolling-element bearing cage 10c. A snap arm 20c is arranged with respect to a circumferential direction of the rolling bearing cage between two pockets 18c, 36c of the rolling bearing cage arranged adjacent to each other in the circumferential direction. A first of the pockets 18c is delimited by a lateral ring 40c of the first cage ring 12c and a lateral ring 50c of the second cage ring 22c and a first crosspiece 52c of the rolling-element bearing cage and a second crosspiece 54c of the rolling-element bearing cage, wherein the second crosspiece has a greater distance from the snap arm 20c than the first crosspiece. The snap arm and an extension 14c are disposed spaced from the first crosspiece. The snap arm is also spaced from those crosspieces that delimit the pocket 36c. In the present exemplary embodiment, the rolling-element bearing cage is a cage of a cylindrical roller bearing. In alternative embodiments the crosspieces can also be shaped such that they are adapted to rolling-elements of a different geometry, such as, in particular, balls.

[0059] Representative, non-limiting examples of the present invention were described above in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Furthermore, each of the additional features and teachings disclosed above may be utilized separately or in conjunction with other features and teachings to provide improved rolling element bearing cages and assemblies including such cages.

[0060] Moreover, combinations of features and steps disclosed in the above detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Furthermore, various features of the above-described representative examples, as well as the various independent and dependent claims below, may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings.

[0061] All features disclosed in the description and/or the claims are intended to be disclosed separately and independently from each other for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter, independent of the compositions of the features in the embodiments and/or the claims. In addition, all value ranges or indications of groups of entities are intended to disclose every possible intermediate value or intermediate entity for the purpose of original written disclosure, as well as for the purpose of restricting the claimed subject matter.

REFERENCE NUMBER LIST

[0062] 10 Rolling-clement bearing cage [0063] 12 Cage ring [0064] 14 Extension [0065] 16 Boundary [0066] 18 Pocket [0067] 20 Snap arm [0068] 22 Cage ring [0069] 24 Attachment region [0070] 26 Section [0071] 28 Central axis [0072] 30 Radial direction [0073] 32 Surface region [0074] 34 Snap arm [0075] 36 Pocket [0076] 38 Partial region [0077] 40 Lateral ring [0078] 41 End [0079] 42 Partial region [0080] 44 Plane [0081] 46 Plane [0082] 48 Recess [0083] 50 Lateral ring [0084] 52 Crosspiece [0085] 54 Crosspiece