FR2773857A1 - Clutch thrust bearing - Google Patents

Abstract

The bearing consists of concentric exterior (1) and interior (2) sleeves, with formed rolling paths formed on each sleeve containing a ball bearing assembly (3) held together by a cage (4). The internal volume between the rolling balls (3) and the sleeves (1,2) is occupied by a solid lubricant (5) which envelopes the balls (3) up to their contact point with both the cage (4) and the rolling paths.

Description

BEARING FOR RELEASE STOP
The present invention relates to a clutch release clutch release bearing and more particularly relates to a bearing for a clutch release bearing having concentric inner and outer rings and lubricated rolling bodies.

 Conventionally, the lubrication of bearings intended to be mounted on release bearings is ensured by a grease maintained inside the rings by means of seals.

 A drawback of this type of bearing lies in the fact that the operating constraints of a clutch release bearing are such that the life of the bearing is generally limited by lubrication problems, this despite the development of new greases and the adoption of ever more sophisticated sealing systems. This lack of lubrication of the rolling bodies is generally due to the ejection of the lubricant out of the raceways by centrifugal force and to the migration, in more or less large quantity of the lubricant towards the outside of the bearing.

 Indeed, a clutch release bearing often operates under extremely severe operating conditions, at high temperature, often above 100 "C and with a high speed of rotation, making the bearing seal difficult to achieve. It is known from the document FR-A-2 675 877, to improve the tightness of the bearings for the clutch release bearing and increase their service life, to use lip seals reacting to centrifugal force and providing a constant contact pressure of the lip on the friction surface.

 However, such seals are relatively complex to produce and the use of a simple sealing lip does not guarantee perfect sealing of the bearing over time. Furthermore, the need for a reduced friction torque of the bearing, so as to allow rapid rotation of the rotating ring, prevents the use of a high contact pressure between the sealing lip and the surface of friction or the multiplication of the number of sealing lips, necessary to obtain a reliable bearing seal over time.

 The object of the present invention is therefore to propose a bearing for a clutch release bearing ensuring better lubrication of the rolling bodies so as to prolong the life of the bearing and which is easy to assemble and economical to produce.

 The subject of the invention is a bearing for a clutch release bearing comprising an inner ring, a concentric outer ring, raceways formed on one and the other ring and a set of rolling bodies connected together by a cage.

 According to the invention, the bearing for a clutch release bearing is characterized in that the internal volume of the bearing comprised between said rolling bodies and inner and outer rings is occupied by a solid lubricant which envelops the rolling bodies until close to their contact with the cage and the raceways.

 According to a characteristic of the bearing according to the invention, the cage has, near the rolling bodies, cavities intended to receive solid lubricant.

 This characteristic makes it possible to increase the mass of solid lubricant in contact with the rolling bodies and therefore to improve the lubrication of the latter.

 According to another characteristic of the bearing which is the subject of the invention, the cage is completely enveloped by the solid lubricant to form a ring of solid lubricant integrating the rolling bodies and the cage.

 According to yet another characteristic of the bearing which is the subject of the invention, deflectors are arranged on either side of the solid lubricant.

 This characteristic protects the lubricating ring against impurities.

The aims, aspects and advantages of the present invention will be better understood from the description given below of an embodiment of the invention, presented by way of non-limiting example, with reference to the accompanying drawings, wherein
- Figure 1 is a half view, in axial section, of a bearing for a clutch release bearing according to the invention;
- Figure 2 is a plan view along II-II of the cage and the rolling bodies covered with a solid lubricant of the bearing according to the invention.

 To make the drawings easier to read, similar elements have the same references from one figure to another.

 FIG. 1 represents a clutch release bearing comprising an outer ring 1 and an inner ring 2.

 The outer ring 1 has, in known manner, a dropped edge 7 directed radially towards the axis of rotation of the bearing and adapted to act on the diaphragm of the clutch mechanism. The inner ring 2 also carries in known manner, a fallen edge 10, directed radially towards the axis of rotation of the bearing and intended to be mounted in abutment on a support, not shown, subjected to the action of an operating member. .

 The rings 1 and 2 are arranged concentrically and delimit an annular space receiving rolling bodies 3 coming into contact with mounted in a cage 4 and take place in housings 9 regularly spaced, the shape of the housings 9 being adapted to leave cavities 8 to proximity to rolling bodies 3.

 A solid lubricant 5, the formulation of which corresponds to a solidified mixture of an oil and a resin, is introduced into the internal volume of the bearing comprised between the outer 1 and inner 2 rings and delimited by two deflectors 6a and 6b arranged on the side and on the other side of the rolling bodies 3 and of the cage 4.

 The introduction of the solid lubricant 5 can be carried out for example in the liquid phase, at high temperature, before the installation of the deflector 6a, the lubricant 5 coming to cover the whole of the cage 4 and the cavities 8 to come close to the rolling bodies 3 and their contacts with the raceways. The lubricant 5 is then brought to a temperature allowing it to pass into the solid phase so as to form a lubricating ring protected from impurities by the defectors 6a and 6b.

 Thanks to its solid state, the lubricant 5 is kept close to the contacts between rolling bodies 3 and raceways of the rings 1 and 2 and thus ensures perfect lubrication of the bearing even at high speed of rotation. Furthermore, as can be seen in FIG. 2, the cavities 8 of the cage 4 make it possible to increase the quantity of grease stored near the rolling bodies 3 and to keep the lubricant 5 at this location during the entire operating time. of the bearing.

 The application of lubricant 5 such as denial avoids the use of additional sealing means, necessary to retain the lubricant but creates an additional friction torque, and therefore ensures for a reduced friction torque between the outer and inner rings extended bearing life.

 Of course, the invention is in no way limited to the embodiment described and illustrated, which has been given only by way of example. Thus it is possible in a simplified embodiment of the bearing according to the invention, not shown in the figures, to remove the deflectors 6a and 6b, the solid lubricant 5 then constituting an annular lubricating ring which opens into contact with the lateral faces of the bearing and whose rigid blanks provide protection against impurities.

Claims (1)

 CLAIMS [1] Bearing for declutching bearing comprising an outer ring (1), an inner ring (2) concentric, raceways formed on both rings (1,2) and a set of rolling bodies (3) interconnected by a cage (4), characterized in that the internal volume of the bearing comprised between said rolling bodies (3) and rings (1,2) is occupied by a solid lubricant (5) which envelops the bodies rollers (3) until close to their contact with the cage (4) and the raceways. [2] Bearing for a clutch release bearing according to claim 1, characterized in that the cage (4) has, near the rolling bodies, cavities (8) intended to receive solid lubricant (5). [3] Bearing for a clutch release bearing according to any one of claims 1 and 2, characterized in that said cage (4) is completely enveloped by the solid lubricant (5) to form a ring of solid lubricant integrating the rolling bodies ( 3) and the cage (4). [4] Bearing for clutch release bearing according to any one of claims l to 3, characterized in that deflectors (6a, 6b) are arranged on either side of the solid lubricant (5).