CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application no. 102019201119.5, filed Jan. 29, 2019, the contents of which are fully incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a suspension thrust bearing device, in particular of the MacPherson type (“MacPherson Suspension Bearing Unit” or MSBU). The invention also relates to a strut for a motor vehicle, comprising a damper and such a suspension thrust bearing device. The field of the invention is that of suspension systems, notably motor-vehicle suspension systems.

BACKGROUND OF THE INVENTION

In a known manner, a motor vehicle suspension system comprises a suspension strut supporting an axle and a vehicle wheel. A suspension thrust bearing device is disposed in an upper portion of the suspension strut, opposite to the wheel and the ground, and between a suspension spring and an upper support block attached to the vehicle chassis.

The suspension thrust bearing device includes at least one bearing, for example a rolling bearing, comprising upper and lower annular bearing members in relative rotation around a main axis.

The suspension thrust bearing device enables transmission of axial forces between the spring and the body of the vehicle and, in the meantime, allows relative angular movement between the spring, which is mobile in rotation, and the fixed support block attached to the body.

The damping function of the suspension thrust bearing device can be improved using a damping element made of resilient material and mounted between the lower annular bearing member and the suspension spring. In a known manner, the damping element is overmolded onto the lower member.

However, the axial load and vibrations of suspension spring onto the damping element may induce axial and radial deformations of the element. Relative micro displacements may be induced between the damping element and the lower bearing element. This undesired damping element displacement leads to separation of damping element from the lower bearing element. The consequences are negative impact on damping performances. The suspension strut may have a reduced service life. It also leads to an extra noise which must be prohibited.

SUMMARY OF THE INVENTION

The aim of the invention is to overcome these drawbacks by proposing an enhanced suspension thrust bearing device. It is desirable to provide a suspension thrust bearing device which is relatively inexpensive, has a good operational reliability, and has an increased service life.

To this end, the invention relates to a suspension thrust bearing device, for use with a suspension spring in an automotive suspension strut of a vehicle. The suspension thrust bearing device comprises a bearing having upper and lower annular bearing members in relative rotation. The lower annular bearing member has a body provided with an embedded stiffening insert.

The suspension thrust bearing device further comprises a damping element made of resilient material and interposed between the lower annular bearing member and the suspension spring.

According to the invention, the body of annular bearing member comprises at least one body through hole, and the embedded stiffening insert also comprises at least one insert through hole provided within the body through hole. The insert through hole is of lower diameter than the body through hole. The damping element further comprises at least one extending pin arranged within the body and insert through holes, the pin having a circumferential groove wherein the insert is fitted.

According to further aspects of the invention which are advantageous but not compulsory, such a suspension thrust bearing device may incorporate one or several of the following features:

The suspension thrust bearing device comprises a bearing with a first ring fixed to an upper cap, so as to form the upper annular bearing member of the suspension thrust bearing, and a second ring fixed to a lower cap, so as to form the lower annular bearing member of the suspension thrust bearing.

The first and second rings are made from a stamped metal sheet.

The upper and lower caps are made from a rigid plastic material.

The bearing is a rolling bearing, the first and second rings defining an annular rolling chamber between them and at least one row of rolling elements being disposed within the rolling chamber.

The rolling elements are balls.

The damping element is directly molded on the lower annular bearing member.

The damping element comprises rubber thermoplastic elastomer (TPE), in particular thermoplastic polyurethane (TPU), melt processible elastomer (MPE) or elastomer cellular foam.

The lower bearing member and the embedded stiffening insert comprise each a plurality of circumferentially arranged through holes.

The body and insert through holes are equally circumferentially spaced.

The lower cap comprises a radial flange, a stiffening insert being embedded within the radial flange.

The lower cap comprises an axial hub, a stiffening insert being embedded within the axial hub.

The radial flange and the embedded stiffening insert comprise each at least one of the through hole.

The axial hub and the embedded stiffening insert comprise each at least one of the through hole.

The invention also relates to a motor vehicle suspension strut comprising a damper rod, a suspension spring, and a suspension thrust bearing device as mentioned above.

