Cage for a rolling bearing

Abstract

The cage (18) for a rolling bearing is intended to ensure the circumferential spacing of at least one row of balls and comprises a plurality of cells (24) for the balls of said row. The cage comprises an annular heel (20) and separation portions (22) extending from the heel and delimiting between each other said cells. The cage also comprises at least one reinforcing ring (25) that is embedded at least partially inside the heel (20) and that extends, inside said cage, exclusively in the heel.

Description

[0001] Description

[0002] Title: Cage for a rolling bearing

[0003] Technical field of the invention

[0004] The present invention relates to the field of cages for rolling bearings intended to ensure the circumferential spacing of at least one row of balls, and notably cages intended for applications involving high rotational speeds.

[0005] Prior art

[0006] Conventionally, a cage comprises an annular heel and separation portions extending from the heel and delimiting between each other cells for seating the balls. The separation portions are usually provided with claws to delimit the cells and to ensure the cage is retained on the balls. For more details on the design of such a cage, reference may for example be made to patent FR 2911934 Bl.

[0007] For reasons of cost and weight, this type of cage is usually made of synthetic material.

[0008] For applications involving high rotational speeds or high temperatures, the cage may become deformed, resulting in contact with the rings of the bearing and / or an enlargement of the cells, which may lead to the balls becoming separated from the cage.

[0009] To overcome these drawbacks, one solution involves increasing the thickness of the heel of the cage. However, this may be incompatible with the specifications in some applications.

[0010] Another solution involves reducing the radial dimension of the separation portions of the cage so that these portions are less sensitive to the centrifugal effects. However, this may result in the balls being lost.

[0011] The present invention is intended to address these drawbacks.

[0012] Summary of the invention

[0013] The invention relates to a cage for a rolling bearing intended to ensure the circumferential spacing of at least one row of balls and comprising a plurality of cells for the balls of said row. The cage comprises an annular heel and separation portions extending from the heel and delimiting between each other said cells.

[0014] According to a general feature, the cage also comprises at least one reinforcing ring that is embedded at least partially inside the heel and that extends, inside said cage, entirely in the heel.

[0015] The reinforcing ring increases the mechanical strength of the cage. The reinforcing ring stiffens the cage only when it is deformed.

[0016] The reinforcing ring limits the deformations of the cage in applications of the cage involving high rotational speeds or high temperatures. By stiffening the cage, the reinforcing ring also improves reactivity during significant accelerations.

[0017] The heel is preferably provided with a first front face and an opposing second front face from which the separation portions extend. The first and second front faces axially delimit the axial thickness of the heel. Said reinforcing ring is entirely located, inside said cage, between the first and second front faces.

[0018] In one embodiment, the cage comprises a plurality of recesses spaced apart from one another in the circumferential direction. Each recess may extend in the thickness of one of the separation portions and be open radially on the inside. The recesses may extend from the first front face of the heel.

[0019] The recesses may be used to centre the reinforcing ring in the related production mould. The recesses also provide the cage with a substantially constant thickness.

[0020] Said reinforcing ring may be flush with the bottom of each recess. Alternatively, said reinforcing ring may remain radially remote from the bottom of each recess.

[0021] In one embodiment, the reinforcing ring is open at a point on the circumference thereof. The reinforcing ring is thus provided with opposing first and second ends that delimit the ring in the circumferential direction and that are spaced apart from one another.

[0022] The opening may be located circumferentially in the zone of one of the separation portions. Alternatively, the opening may be located circumferentially between two successive separation portions.

[0023] Alternatively, the first and second ends of the ring could bear against one another. In another variant, the reinforcing ring could be annular, i.e. continuous in the circumferential direction.

[0024] Said reinforcing ring may have a square or rectangular or circular profile in cross section.

[0025] Preferably, the heel and the separation portions of the cage are made as a single part by moulding at least one synthetic material.

[0026] The outer surface of said reinforcing ring may have hollow elements, for example slots and / or grooves, to engage the heel therewith.

[0027] The invention also relates to a bearing comprising an inner ring, an outer ring, at least one row of balls arranged between said rings, and a cage as defined above.

[0028] Brief description of the figures

[0029] The present invention will be better understood on studying the detailed description of embodiments, given by way of entirely non-limiting example and illustrated by the appended drawings, in which :

[0030] [Fig 1] is a partial perspective view of a rolling bearing according to an example embodiment of the invention,

[0031] [Fig 2] is a perspective view of the cage of the bearing in Figure 1,

[0032] [Fig 3] is a front view of the cage in Figure 2,

[0033] [Fig 4] is a view in cross section along the line IV-IV in Figure 3, and

[0034] [Fig 5]

[0035] [Fig 6]

[0036] [Fig 7]

[0037] [Fig 8] are views in cross section of the cage for rolling bearings according to other example embodiments of the invention.

[0038] Detailed description of the invention

[0039] As shown in Figure 1, the rolling bearing 10 comprises an outer ring 12, an inner ring 14, a plurality of balls 16 arranged radially between the rings, and a cage 18 for maintaining the regular circumferential spacing of the balls. The outer ring 12 and inner ring 14 are in this case solid. A "solid ring" is understood to mean a ring having a shape obtained by machining with stock removal (turning or grinding) from tubes, bars, or forged and / or rolled blanks. As illustrated more clearly in Figures 2 and 3, the cage 18 comprises an axial portion or annular heel 20 intended to be arranged axially on one side of the balls, and fingers or separation portions 22 extending axially from the heel 20 and spaced apart from one another in the circumferential direction. The separation portions 22 delimit between each other cells 24 in which the balls are arranged. Each cell 24 is delimited in the circumferential direction by two successive separation portions 22. Each cell 24 is open radially inwards and outwards, and is also open axially on the side opposite the heel 20. The separation portions 22 and the cells 24 are in this case respectively identical to one another.

[0040] The heel 20 and the separation portions 22 of the cage are advantageously produced as a single part by moulding a synthetic material, such as, for example, polyamide, notably PA 66 or PA 46, or alternatively a polyetheretherketone (PEEK).

[0041] As described in greater detail below, the cage 18, having an axis 18a, also comprises a reinforcing ring 25 partially embedded inside the heel 20. The reinforcing ring 25 may be made of metal, for example steel or aluminium, or an alloy, or may alternatively be made of rigid synthetic material.

[0042] With reference now to Figure 4, the heel 20 of the cage is provided with a first front face 20a and an opposing second front face 20b delimiting the axial thickness of said heel. The front faces 20a, 20b in this case extend radially.

[0043] The separation portions 22 of the cage extend axially from the front face 20b of the heel on the opposite side to the front face 20a. The separation portions 22 are in the form of pins projecting axially from the heel 20. Each separation portion 22 is delimited radially by an inner surface aligned with the bore of the heel 20.

[0044] Each separation portion 22 has, on each side in the circumferential direction, a spherical wall connected to the spherical wall of the adjacent separation portion 22 to form the related cell 24.

[0045] Each separation portion 22 comprises two claws 26 extending axially away from the heel 20 and extending circumferentially in opposite directions. Each of the claws 26 of each separation portion 22 axially and circumferentially extends one of the spherical walls of said separation portion. For a given cell 24, the spherical walls and the claws 26 of the separation portions 22 tend to envelop the related ball.

[0046] Each claw 26 extends towards the claw 26 of the adjacent separation portion 22 to delimit the related cell 24. The free ends of the two adjacent claws 26 of two adjacent separation portions 22 are spaced apart by a distance less than the diameter of the related ball. The claws 26 are capable of axially retaining the cage 18 by snap-fitting onto the ball arranged in the related cell 24. The cage 18 is retained axially on the balls by the claws 26. The claws 26 of each separation portion 22 are separated in the circumferential direction by a recess 28 so that they each have a relatively small circumferential thickness and a degree of flexibility enabling the cage 18 to be snap-fitted on the rolling elements.

[0047] The cage 18 also comprises a plurality of recesses 30 spaced apart from one another in the circumferential direction, in this case regularly. Each recess 30 extends in the radial thickness of one of the separation portions 22 and is open radially on the inside. Each recess 30 extends radially from the inner surface of the related separation portion 22. Each recess 30 extends axially from the front face 20a of the heel to the related separation portion 22 while remaining axially distant from the recess 28. Each recess 30 has a generally rectangular shape.

[0048] As mentioned above, the cage 18 also comprises the reinforcing ring 25 partially embedded inside the heel 20. The reinforcing ring 25 is coaxial with the axis 18a of the cage. Inside the cage 18, the reinforcing ring 25 extends exclusively in the heel 20. In other words, inside the cage 18, the reinforcing ring 25 does not extend inside the separation portions 22. Inside the cage 18, the reinforcing ring 25 is entirely located between the front faces 20a, 20b of the heel, considering the axial direction.

[0049] As shown notably in Figure 2, the reinforcing ring 25 is in this case open at one point on the circumference thereof. The reinforcing ring 25 is provided with opposing first and second ends that delimit the ring in the circumferential direction. The opening in the reinforcing ring 25 is located circumferentially in the zone of one of the separation portions 22. The opening in the reinforcing ring 25 is therefore located in the axial extension of this separation portion 22. With reference again to Figure 4, the reinforcing ring 25 is provided with a first front face 25a and an opposing second front face 25b delimiting the axial thickness of said ring. The front faces 25a, 25b in this case extend radially. In the example embodiment illustrated, the reinforcing ring 25 is flush with the front face 20a of the heel. The front face 25a of the reinforcing ring is flush with this front face 20a. The remainder of the reinforcing ring 25 is embedded inside the heel 20.

[0050] Alternatively, the reinforcing ring 25 may be arranged otherwise inside the heel 20 of the cage.

[0051] For example, the front face 25a of the reinforcing ring could be embedded inside the heel 20 and the bore of said ring could be flush with the bottom of each recess 30.

[0052] Another possible arrangement is illustrated in Figure 5, which differs from the first illustrated example only in that the reinforcing ring 25 is located at the centre of the heel 20 of the cage, considering the radial direction.

[0053] Yet another possible arrangement is illustrated in Figure 6, which differs from the first illustrated example only in that the outer surface of the reinforcing ring 25 is flush with the outer surface of the heel 20 of the cage.

[0054] In the example embodiment illustrated in Figure 7, the reinforcing ring 25 is flush with the bottom of each cell 24. More specifically, the front face 25b of the reinforcing ring is flush with the bottom of each cell 24.

[0055] In the example embodiments illustrated previously, the reinforcing ring 25 has a square profile in cross section. In a variant, the reinforcing ring 25 may have a different profile, for example a triangular, rectangular or even circular profile, as illustrated in Figure 8.

[0056] In the example embodiments described above, the reinforcing ring 25 is only partially embedded inside the heel 20. This makes it easier to position and hold the reinforcing ring 25 inside the related production mould before overmoulding the synthetic material of the heel 20 and of the separation portions 22.

[0057] In a variant, the reinforcing ring 25 may nonetheless be entirely embedded inside the heel 20. In the example embodiments illustrated, a single reinforcing ring 25 is embedded inside the heel 20. Alternatively, several reinforcing rings could be embedded inside the heel 20.

[0058] In the example embodiments illustrated, the reinforcing ring 25 is in the form of a flat ring. In a variant, the reinforcing ring could have corrugations in the radial direction and / or in the axial direction. In another variant, the reinforcing ring could be provided in the form of a winding of coils.

Claims

Claims1. Cage (18) for a rolling bearing intended to ensure the circumferential spacing of at least one row of balls and comprising a plurality of cells (24) for the balls of said row, the cage comprising an annular heel (20) and separation portions (22) extending from the heel and delimiting between each other said cells, characterized in that it also comprises at least one reinforcing ring (25) that is embedded at least partially inside the heel (20) and that extends, inside said cage, exclusively in the heel.

2. Cage according to Claim 1, wherein the heel (20) is provided with a first front face (20a) and an opposing second front face (20b) from which the separation portions (22) extend, the first and second front faces (20a, 20b) axially delimiting the axial thickness of the heel, and said reinforcing ring (25) being entirely located, inside said cage, between the first and second front faces (20a, 20b).

3. Cage according to Claim 2, wherein said reinforcing ring (25) is flush with the first front face (20a) of the heel.

4. Cage according to any one of the preceding claims, comprising a plurality of recesses (30) spaced apart from one another in the circumferential direction, each recess (30) extending in the thickness of one of the separation portions (22) and being open radially on the inside.

5. Cage according to Claim 4 when dependent on Claim 2 or 3, wherein the recesses (30) extend from the first front face (20a) of the heel.

6. Cage according to Claim 4 or 5, wherein said reinforcing ring (25) is flush with the bottom of each recess (30).

7. Cage according to any one of the preceding claims, wherein said reinforcing ring (25) is made of metal.

8. Cage according to any one of the preceding claims, wherein said reinforcing ring (25) is open at a point on the circumference thereof, the opening being located circumferentially in the zone of one of the separation portions.

9. Cage according to any one of the preceding claims, wherein said reinforcing ring (25) has a square or rectangular or circular profile in cross section.

10. Rolling bearing comprising an inner ring (12), an outer ring (14), at least one row of balls (16) arranged between said rings, and a cage (18) according to any one of the preceding claims.

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