Method for machining a bearing ring and for producing a rolling bearing

Abstract

A method for machining a bearing ring of a rolling bearing includes clamping a blank for the bearing ring in a machining machine, and applying a pulsating pressure using a machining body to structure and simultaneously harden an annularly closed sealing surface of the blank. The machining body may be a spherical machining body. The method may also include removing material from the blank to produce a bearing ring track using the same clamping. The blank may be rotated during the applying a pulsating pressure step and the removing material step.

Claims

1.-10. (canceled)

11. A method for machining a bearing ring of a rolling bearing, comprising: clamping a blank for the bearing ring in a machining machine; and applying a pulsating pressure using a machining body to structure and simultaneously harden an annularly closed sealing surface of the blank.

12. The method of claim 11, wherein the machining body is a spherical machining body.

13. The method of claim 11, further comprising removing material from the blank to produce a bearing ring track using the same clamping, wherein the blank is rotated during the applying a pulsating pressure step and the removing material step.

14. The method of claim 11, further comprising displacing the bearing ring blank in an axial direction during the applying a pulsating pressure step.

15. The method of claim 14, wherein the machining body applies the pulsating pressure to the annularly closed sealing surface in a helical line.

16. The method of claim 14, wherein the machining body applies the pulsating pressure to the annularly closed sealing surface in a wavy line that intersects itself multiple times.

17. The method of claim 11, further comprising displacing the bearing ring blank in a radial direction during the applying a pulsating pressure step.

18. The method of claim 17, wherein the machining body applies the pulsating pressure to the annularly closed sealing surface in a spiral line.

19. The method of claim 17, wherein the machining body applies the pulsating pressure to the annularly closed sealing surface in a wavy line that intersects itself multiple times.

20. A method for producing a rolling bearing comprising: providing the bearing ring of claim 11 with the annularly closed sealing surface comprising depressions; providing a second bearing ring; placing a plurality of rolling element between the bearing ring and the second bearing ring; and installing a seal onto the second bearing ring such that is contacts the annularly closed sealing surface.

21. A rolling bearing, comprising: a first bearing ring comprising a hardened surface having a plurality of depressions; a second bearing ring; a plurality of rolling elements arranged between the first bearing ring and the second bearing ring; and a seal fixed to the second bearing ring and contacting the hardened surface.

22. The rolling bearing of claim 21 wherein the rolling bearing is a wheel bearing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Below, two exemplary embodiments are explained in more detail by means of a drawing. In the figures:

[0029] FIG. 1 shows a schematic representation of the machining of a surface of a bearing ring by means of pulsating application of pressure,

[0030] FIG. 2 shows a perspective view of the bearing ring machined with the method according to FIG. 1,

[0031] FIG. 3 shows a rolling bearing designed as a deep groove ball bearing including the bearing ring according to FIG. 2, and

[0032] FIG. 4 shows a section of a rolling bearing designed as a wheel bearing with a bearing ring machined according to FIG. 1.

DETAILED DESCRIPTION

[0033] Unless otherwise stated, the following explanations relate to both exemplary embodiments. Parts or structures that correspond to each other or have basically the same effect are marked with the same reference symbols in all figures.

[0034] A rolling bearing identified overall with the reference number 1 is designed as a ball bearing and includes an inner ring 2 and an outer ring 3. The rolling bearing 1 shown in FIG. 3 is a deep groove ball bearing, while the rolling bearing 1, only partially sketched in FIG. 4, is a two-row angular ball bearing, namely a wheel bearing for a motor vehicle. In this case, a flange of the inner ring 2 is denoted by 4.

[0035] In both cases, balls roll as rolling elements 5 between the bearing rings 2, 3. The balls 5 can be guided in a cage (not shown). A track of the inner ring 2 coming into contact with the rolling elements 5 is denoted by 6, and a track of the outer ring 3 is denoted by 7.

[0036] A seal 8, which has a sealing lip 9, is held on the outer ring 3. The sealing lip 9 comes into contact with a surface 10 of the inner ring 2 which, in the case of FIG. 3, describes a cylinder which is concentric to the central axis M of the rolling bearing 1. In the case of FIG. 4, on the other hand, the surface 10 lies on a plane which is oriented normal to the central axis M. In both cases, the seal 8 is a contact seal. In a manner not shown, the seal 8 can have more than one sealing lip 9.

[0037] The surface 10, which is contacted by the sealing lip 9, is structured by means of a method which is illustrated in FIG. 1 and provides a surface structuring 11. This method is used in the production of the inner ring 2 of the rolling bearing 1 according to FIG. 3 as well as in the production of the inner ring 2 of the rolling bearing 1 according to FIG. 4.

[0038] To produce the inner ring 2, a blank, the basic shape of which corresponds to the shape of the later inner ring 2, is clamped into a machining machine (not shown), e.g., a lathe. During the following machining, the blank, i.e., the later inner ring 2, rotates about the central axis M thereof. The machining of the blank while it is being clamped in the machining machine includes the cutting machining of the rolling element track 6.

[0039] In the example sketched out in FIGS. 1 to 3, the rolling bearing 1 is only sealed on one side. Accordingly, the rolling bearing 1 has only a single cylindrical surface 10, Which functions as a sealing surface within the fully assembled rolling bearing 1 (FIG. 3). The surface structuring 11 of the surface 10 indicated in FIG. 2 is also given in the exemplary embodiment according to FIG. 4. The surface structuring 11 has the form of numerous depressions 12, which are distributed almost randomly on the surface 10. The roughness depth R.sub.t of the structured surface 10 is in the range from 3 to 5 μm.

[0040] A tool 13, which is indicated in FIG. 1, is used to produce the depressions 12. The tool 13 is installed on the machining machine, e.g., a lathe, and includes a machining ball 14, which is generally referred to as a machining body. The machining ball 14 is rotatably arranged inside the tool 13 and is supported by a liquid cushion inside the tool 13. By generating an oscillating pressure that acts within the liquid cushion, an oscillation of the machining ball 14 is produced, which is referred to as vertical oscillation V without loss of generality. In the example according to FIG. 1, the vertical oscillation V is oriented in the radial direction with respect to the central axis M. In contrast, when machining the inner ring 2 of the rolling bearing 1 according to FIG. 4, a vertical oscillation V is to be generated, which is oriented in the axial direction with respect to the central axis M. The frequency of the vertical oscillation V is significantly higher than the speed of the inner ring 2 in both cases.

[0041] In the case of FIG. 1, an axial displacement AV of the tool 13 is superimposed on the vertical oscillation V. The axial displacement AV is also an oscillating movement. This oscillation describes a wavy line on the surface 10 along which lie the depressions 12. In the course of the multiple revolutions of the inner ring 2, multiple overlaps of this wavy line occur, so that ultimately the desired quasi-statistical distribution of the depressions 12 on the surface 10 occurs.

[0042] In a modified method, it is possible to move the machining body of the tool 13 only once in the axial direction over the surface 10, wherein the axial displacement AV in this case is much slower than in the case of the wave-shaped machining paths. The slow, one-time movement of the tool 13 theoretically generates a helical line on the surface 10. The slope of this helical line is so small that in this case too, a distribution of the depressions 12 on the surface 10 that ultimately results is uniform to a very good approximation.

[0043] To produce the surface structuring of the inner ring 2 according to FIG. 4, the tool 13 is, for example, moved slowly and evenly radially from the inside to the outside or from the outside to the inside. The depressions 12 thus generated theoretically lie on a spiral line. If, on the other hand, the tool 13 is moved at a comparatively high frequency between a first extreme point, which lies radially inward, and a second extreme point, which represents the radially outer boundary of the surface 10, then waveforms of the structuring 11 arise first which lie in a single plane, namely the plane of the surface 10. In the course of several revolutions of the inner ring 2, these waves overlap several times, in principle comparable to the exemplary embodiment according to FIG. 1, so that also in this case a high uniformity is achieved in the distribution of the depressions 12 within the surface 10.

REFERENCE NUMERALS

[0044] 1 Rolling bearing [0045] 2 Inner ring [0046] 3 Outer ring [0047] 4 Flange [0048] 5 Rolling element [0049] 6 Inner ring track [0050] 7 Outer ring track [0051] 8 Seal [0052] 9 Sealing lip [0053] 10 Surface [0054] 11 Surface structuring [0055] 12 Depression [0056] 13 Tool [0057] 14 Machining ball [0058] AV Axial displacement [0059] M Central axis [0060] V Vertical oscillation