Rolling bearing

Abstract

A rolling bearing is disclosed which comprises an outer ring and an inner ring, wherein rolling elements are arranged between the outer ring and the inner ring, and wherein the rolling elements are spaced apart by a cage being arranged between the outer ring and the inner ring, wherein the cage is made of polymer containing reinforcing fibers, and the outer ring and/or the inner ring are steel rings with fine carbide precipitation.

Claims

1. A rolling bearing comprising: an outer ring and an inner ring, wherein the outer ring and/or the inner ring is formed from a steel with carbide precipitation, a bearing cage between the inner ring and the outer ring; and a plurality of rolling elements retained by the cage, the cage maintaining a spacing of the plurality of rolling elements; wherein the cage comprises reinforcing fibers in a polymer matrix, and wherein particles of the steel are completely embedded in the polymer matrix.

2. The rolling bearing according to claim 1, wherein the cage contains more than 15% volume fraction of the reinforcing fibers.

3. The rolling bearing according to claim 1, wherein the polymer matrix has a hardness of about 35 HB and the reinforcing fibers have a hardness of about 1000 HB.

4. The rolling bearing according to claim 1, wherein the polymer is polyether ether ketone.

5. The rolling bearing according to claim 1, wherein the reinforcing fibers are carbon fibers or glass fibers or steel fibers.

6. The rolling bearing according to claim 1, wherein the reinforcing fibers are steel fibers.

7. A rolling bearing comprising: an outer ring formed from a steel with carbide precipitation; an inner ring formed from the steel, a bearing cage between the inner ring and the outer ring; and a plurality of rolling elements retained by the cage, the cage maintaining a spacing of the plurality of rolling elements; wherein the cage is formed of polyether ether ketone containing reinforcing fibers, the reinforcing fibers having a hardness of about 1000 HB, wherein the cage includes particles of the steel completely embedded in the polyether ether ketone, wherein the polymer contains more than 15% volume fraction of the reinforcing fibers, and wherein the reinforcing fibers are carbon fibers or glass fibers or steel fibers.

8. The rolling bearing according to claim 7, wherein the reinforcing fibers are the steel fibers.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the following, the present invention will be described by means of embodiments shown in the figures. The shown embodiments are exemplarily, only, and are not intended to limit the scope of protection. The scope of protection is solely defined by the attached claims.

(2) FIG. 1 shows a top view of a rolling bearing; and

(3) FIG. 2 shows a perspective view of a polymer cage used in the rolling bearing of FIG. 1.

DETAILED DESCRIPTION

(4) In the following same or similar functioning elements are indicated with the same reference numerals.

(5) FIG. 1 shows a rolling bearing 1 comprising an outer ring 2 and an inner ring 4. Between the outer ring 2 and the inner ring 4, a cage 6 is arranged for guiding rolling elements 8 and for holding them spaced apart. As shown in FIG. 2, the cage 6 comprises openings 10 which form pockets for receiving the rolling elements 8, in this case balls. However, any other kind of rolling elements 8 may be used.

(6) In the contact region between the rings 2, 4 and the cage 6, contamination with hard particles may occur. These hard particles may originate from the rings 2, 4, in particular when the outer ring 2 and/or the inner ring 4 are steel rings with fine carbide precipitation.

(7) In previous bearings, steel cages with silver plating were used, wherein the silver plating served as a friction reducing and lubricating layer. However, the silver plating is a very soft layer in which hard particles may be captured. When the particles are captured in the silver plating, they typically stick out of the surface of the cage, in particular the silver plating, and may damage the surfaces of the rings 2, 4 in the contact region between the cage 6 and the rings 2, 4.

(8) In order to avoid or at least reduce such capturing of hard particles, a polymer cage 6, in particular a PEEK cage, with a high amount of reinforcing fibers is used in the herein described rolling bearing 1. The reinforcing fibers may be for example carbon fibers. Such a polymer cage 6 provides the following advantages.

(9) Hard particles in the contact region between the cage 6 and the rings 2, 4 may contact the reinforcing fibers which are harder than the hard particles. As a consequence, the hard particles are not able to penetrate the surface of the polymer cage 6 and will slip away out of the contact region. Thus, these particles will not damage the surface of the rings 2, 4.

(10) If the hard particles contact the polymer cage 6 not in an area of reinforcing fibers but at an area where the polymer material is at the surface of the cage 6, the hard particles may penetrate the surface of the polymer cage 6. However, due to the soft polymer material, the hard particles will completely enter into the polymer and will be embedded in the polymer cage 6. Thus, none of these particles will stick out of the surface of the cage 6 and will also not damage the surface of the rings 2, 4.

(11) It may be the case that some of the hard particles will neither slip away due to a contact with the reinforcing fibers nor will be embedded in the polymer material. These particles may stick out of the surface of the cage 6 and may get in contact with the rings 2, 4. However, the number of these particles will be significantly reduced compared to the number of particles which would be captured in a silver-plated cage.

(12) Thus, by providing a rolling bearing having a polymer cage having a high amount of reinforcing fibers, the contamination with hard particles in the surface of the cage may be reduced.

REFERENCE NUMERALS

(13) 1 rolling bearing 2 outer ring 4 inner ring 6 cage 8 rolling elements 10 pockets