TECHNICAL FIELD OF THE INVENTION The invention concerns a rolling bearing assembly. BACKGROUND OF THE INVENTION

Sensor bearing units, for example on two-wheelers, generally comprise a bearing and a sensor unit mounted in a housing. The housing is often made of a light metallic alloy including aluminum. At high temperatures, a clearance provoked by thermal dilatation can appear between the housing and the outer ring of the bearing. In such a case, the sensor body could rotate with respect to the housing. It is known to avoid the clearance by using a bushing or sleeve arranged between the housing and the outer ring of the bearing which can therefore float in an axial direction. The steel bushing is assembled in the housing and the bearing or the sensor bearing is assembled inside the steel bushing. The bushing may comprise a radial portion for supporting an axial preload acting on the outer ring. A wavy spring is provided to generate the axial preload.

A sensor body or sensor housing has to be attached so as to be fixed in relation to the stationary ring. It has been proposed to integrate the sleeve with the sensor body or to arrange the sensor body between the wavy spring and the radial portion of the ring. In both cases, the axial preload is supported on the sensor body such that sensor body cannot be disassembled without disassembling the entire bearing, the preload and the sleeve. Moreover, both the preload effort and the sensor position in relation to the encoder ring are difficult to control.

SUMMARY OF THE INVENTION

The aim of the invention is to provide an improved rolling bearing assembly, in which the integration and detachment of a sensor unit is facilitated.

To this end, the invention concerns a rolling bearing assembly, comprising a bearing including a rotating ring configured to be mounted on a shaft and a stationary ring and a sleeve configured to be mounted in a housing. The sleeve has a cylindrical inner surface configured to be in contact with a radially outer surface of the stationary ring of the bearing and a radial portion protruding from cylindrical inner surface radially inward. A pre- stressing element for pre-stressing the stationary ring is provided and adapted to exert a pre-stressing force between an axially inner surface of the radial portion of the sleeve and the stationary ring. The bearing assembly further includes a sensor unit including an impulse ring coupled in rotation to the rotating ring and a sensing unit comprising at least one sensing element mounted in a sensor body.

It is proposed that the sensor body is mounted on an outer surface of the sleeve. The outer surface can be any surface other than the axially inner surface and the radially inner surface in contact with the pre-stressing element or the stationary ring. Consequently, the sensor body may be mounted or dismounted for assembly, replacement or maintenance purposes without dismounting the pre-stressing element, which is preferably formed as a wavy spring. The preload can be kept and controlled and the control of the sensor placement in relation to the impulse ring is facilitated.

The sleeve may be metallic, e.g. made of steel, or be made of a synthetic material.

In a preferred embodiment of the invention, the sensor body is mounted on one of the axial end faces of the sleeve. Where the sleeve protrudes over the housing, the sensor body may further overlap with or be mounted on the radially outer surface of the sleeve.

In one embodiment of the invention, the axial end face of the sleeve onto which the sensor body is mounted is an axial end face on a side of the radial portion. The larger radial width facilitates the mounting. In a further embodiment of the invention, the axial end face of the sleeve is an axial end face on a side opposite to the radial portion. Further, the sensor body may be mounted on a radially outer surface of the sleeve.

In a preferred embodiment of the invention, the sensor body is detachably fixed to the sleeve by means of at least one screw. The easy attachment and detachment of the sensor body using a simple screw can be obtained in a simple way without disassembling the bearing, the sleeve or bushing or the pre-stressing element.

The positioning of the sensor can be further facilitated by providing the axial end face of the sensor body with a groove configured to receive an axial end portion of the sleeve.

A further aspect of the invention relates to a machine including a rolling bearing assembly according to one of the preceding claims. Further features, functions and advantages of the invention will become apparent upon reading the following description of preferred embodiments of the invention in combination with the attached drawings. This specification, the claims and the drawings describe the features of the invention in specific combinations. The skilled person will consider these features in isolation or find other combinations or sub-combinations of these features in order to adapt the invention to his or her specific needs.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in correspondence with the annexed figures, and as an illustrative example, without restricting the object of the invention. In the annexed figures:

figure 1 is a perspective view of a rolling bearing assembly according to the invention;

figure 2 is a sectional view of the rolling bearing assembly of figure 1 ;

figure 3 is an enlarged view of a detail III of figure 2;

figure 4 figure 2 is a further sectional view across a sensor body of the rolling bearing assembly of figure 1 ;

figure 5 is an enlarged view of a detail V of figure 4;

figure 6 is a sectional view of a rolling bearing assembly according to a second embodiment of the invention; and

Figure 7 is an enlarged view of a detail VII of figure 6; DETAILED DESCRIPTION OF SOME EMBODIMENTS

The rolling bearing assembly A represented on figures 1 to 5 is adapted to be mounted on an automotive vehicle, in particular in an e-machine. The rolling bearing assembly A is mounted on a shaft C, within a housing H as a single and compact sensor bearing unit U.

The rolling bearing assembly A defines a central rotation axis X-X'. In this description, the words "axial" and "radial" are used in reference to axis X-X'.

Referring to figures 2 and 3, a sensor-bearing unit U is a compact pre-assembled unit comprising a rolling bearing 2 including a rotating ring 22 and a stationary ring 24. In the example, the rotating ring 22 is the inner ring, while the stationary ring 24 is the outer ring. The rolling bearing 2 also includes rolling elements, which are balls 26 in this example. In a non-shown embodiment, the rolling bearing 2 may comprise another type of rolling elements, such as rollers or needles.

The sensor bearing unit U comprises a sensor unit 6 which includes an impulse ring 62 coupled in rotation to the rotating ring 22 and a sensing unit 64 comprising at least one sensing element 641 mounted in a sensor body 66.

The sensor-bearing unit U includes a sleeve 8 in which the bearing 2 and the sensor body 66 are mounted. The sleeve 8 comprises a cylindrical portion 80 mounted in a bore H1 of the housing H. The cylindrical portion 80 defines a cylindrical inner surface, against which the stationary ring 24 is mounted, the sleeve 8 thereby providing radial support for the stationary ring 24. The sleeve 8 comprises an inwardly extending radial portion 82 having an axially inner surface against which a pre-stressing element 4 formed as a wavy spring is in direct contact. According to the embodiment of Figure 3, said radial portion 82 consists in an annular rim. Alternatively, the radial portion may consist in a ring mounted within an annular groove of said sleeve 8, or any other appropriate means.

In this context, an axially inner side refers to a side facing the bearing 2 and an outer side refers to a side facing away from the bearing 2. A limited axial displacement of the stationary ring 24 against the effort of a pre-stressing element 4 within the cylindrical inner surface of the sleeve is possible.

The sensor body 66 is mounted on an axial end face of the sleeve 8 on a side opposite to the radial portion 82 of the sleeve 8. The mounting of the sensor body 66 on the sleeve 8 facilitates the assembly of the rolling bearing assembly A and the detachment of the sensor body 66 without disassembling the entire bearing.

The sleeve 8 is made of a metallic material such as steel. As an alternative, the sleeve 8 can be made of a synthetic material, such as polyethylene terephthalate (PET). Such a material is light, not much expensive, provides electric isolation properties and is suitable for compensating dilatation of metallic rings such as the outer ring 24. The housing H may also be made of a synthetic material such as PET. The housing H and the sleeve 8 may both be made of a synthetic material, or only one of the housing H and the sleeve 8 may be made of a synthetic material. As shown in Figs. 4 and 5, the sensor body 66 is detachably fixed to the sleeve 8 by a simple screw 67. Other suitable detachable fixing means may be used as well.

The sensor unit 6 is adapted to transmit sensed data via wire transmission. The sensor unit 6 therefore comprises an output transmission cable 68. In this example, the cable 68 extends in a radial direction.

The pre-stressing element 4 for pre-stressing the stationary ring 24 is adapted to exert a pre-stressing force between radial portion 82 of the sleeve and the stationary ring 24. In the example, the pre-stressing element 4 is a wavy spring comprising alternating waves, which are in contact with one axial end face of the stationary ring 24 and with a radial portion 82 of the sleeve 8.

The axial end face of the stationary ring 24 and the radial portion 82 of the sleeve 8 form a chamber in which the pre-stressing element 4 is mounted. An axial side face of the sensor body 66 facing the rolling bearing 2 is provided with a groove 665 adapted to receive the axial end portion of the sleeve 8.

In the embodiment illustrated in figures 1 to 5, the sensor body 66 is mounted on the end of the sleeve 8 opposite to the end where the radial portion 82 of the sleeve 8 is provided.

A second embodiment of the invention is represented on figures 6 and 7. In this embodiment, elements similar to the first embodiment have the same references and work in the same way. Only the differences with respect to the first embodiment are described hereafter.

As illustrated in figures 6 and 7, the axial direction of the sleeve 8 is reversed as compared to the embodiment illustrated in figures 1 - 5 such that the radial portion 82 is arranged at an end facing to the outside of the housing H.

The sensor body 66 is attached to the end face of the sleeve 8 on the side where the radial portion 82 is provided.

According to a non-shown embodiment, the sensor unit 6 is adapted to transmit sensed data via wireless transmission.

In addition, technical features of the different embodiments can be, in whole or part, combined with each other to form new embodiments of the invention.