SUSPENSION THRUST BEARING DEVICE

A suspension thrust bearing device that provides a lower support cap, an upper bearing cap and at least one bearing arranged between the caps. The upper bearing cap includes an outer skirt radially surrounding the lower support cap. The lower support cap ha at least one annular flange extending towards the outer skirt of the upper bearing cap while remaining radially spaced apart from the outer skirt. The upper bearing cap further includes at least one annular rib extending axially towards an upper surface of the flange of the lower support cap while remaining axially spaced apart from the lower support cap. The annular rib is radially located between the outer skirt of the upper bearing cap and the bearing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application no. 102020200587.7, filed Jan. 20, 2020, the contents of which is fully incorporated herein by reference.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to the field of suspension thrust bearing devices, used in particular for motor vehicles in the suspension struts of the steered road wheels.

BACKGROUND OF THE INVENTION

A suspension thrust bearing device is generally provided with a rolling bearing comprising an upper ring and a lower ring between which are positioned rolling elements, for example balls or rollers, and with lower and upper caps. The lower and upper caps form housings for the rings of the rolling bearing and provide the interface between the rings and the neighboring elements.

The suspension thrust bearing device is arranged in the top part of the suspension strut between the vehicle body and a suspension spring. The suspension spring is mounted around a damping piston rod, the end of which is connected to the vehicle body. The suspension spring axially bears, directly or indirectly, on the lower cap of the thrust bearing device.

The suspension thrust bearing device allows transmission of axial and radial forces between the suspension spring and the vehicle body, while allowing a relative rotational movement between the lower cap and the upper cap resulting from a deflection of the steered wheels of the vehicle and/or compression of the suspension spring.

Generally, the upper cap of the suspension thrust bearing device is provided with a plurality of hooks arranged on an outer skirt and adapted to diametrically interfere with a plurality of hooks of the lower cap. The hooks of each cap are spaced apart from each other in the circumferential direction.

The hooks form retaining means provided to axially retain the upper and lower caps relative to one another. These hooks also form narrow passageways in order to prevent the intrusion of foreign matter radially between the outer skirt of the upper cap and the lower cap.

However, a suspension thrust bearing device is generally exposed to various kinds of pollution.

With such suspension thrust bearing device, pollutants can easily be infiltrated between the outer skirt of the upper cap and the lower cap, and then be directed towards the rolling bearing and be introduced inside the latter.

One aim of the present invention is to overcome this drawback.

SUMMARY OF THE INVENTION

It is a particular object of the present invention to provide a suspension thrust bearing device having good sealing properties to protect the bearing against ingress of pollutants while ensuring a low friction torque.

The invention relates to a suspension thrust bearing device comprising a lower support cap, an upper bearing cap and at least one bearing arranged between the caps, the upper bearing cap comprising an outer skirt radially surrounding the lower support cap.

According to a first general feature, the lower support cap comprises at least one annular flange extending towards the outer skirt of the upper bearing cap while remaining radially spaced apart from the outer skirt.

According to a second general feature, the upper bearing cap further comprises at least one annular rib extending axially towards an upper surface of the flange of the lower support cap while remaining axially spaced apart from the lower support cap. The rib is radially located between the outer skirt of the upper bearing cap and the bearing.

The flange of the lower support cap enables to avoid water flow to go up in the device and damage the bearing. The flange forms a barrier for diverting the water flow directed upwards between the outer skirt of the upper bearing cap and the lower support cap.

Besides, the annular rib of the upper bearing cap forms a vertical barrier arranged radially between the outer skirt of this cap and the bearing to protect the bearing. The annular rib of the upper bearing cap enables to limit pollutants to go up in the device and damage the bearing.

To this end, the annular rib has a lower surface which is preferably axially offset downwards with respect to an uppermost face of the lower support cap, and/or with respect to the outer diameter of the bearing.

In one embodiment, the upper bearing cap comprises a radial portion from which extends the outer skirt and having an upper surface and an opposite lower surface defining the thickness of the radial portion. The annular rib protrudes from the lower surface of the radial portion.

Advantageously, at least an annular axial labyrinth seal is formed between the annular rib of the upper bearing cap and the lower support cap.

In one embodiment, at least a part of the upper surface of the flange of the lower support cap extends obliquely downwards. The flange may also have a lower inclined surface extending obliquely downwards. With the lower inclined surface of the flange, the water flow is re-oriented towards the opening formed between the free end of the outer skirt of the upper bearing cap and the lower support cap. For example, the lower inclined surface of the flange may form an angle with the axis of the device comprised between 45° and 65°.

In one embodiment, the upper bearing cap comprises an inner skirt comprising a plurality of hooks able to interfere diametrically with hooks provided on the lower support cap. Alternatively, the outer skirt of the upper bearing cap may comprise a plurality of hooks able to interfere diametrically with the flange of the lower support cap.

In one embodiment, the lower support cap comprises a radial portion in contact with a lower ring of the bearing, the flange extending outwards from the radial portion. The flange may extend radially outwards from the radial portion of the lower support cap.

The lower support cap may also comprise an annular rib extending axially towards a radial portion of the upper bearing cap while remaining axially spaced apart from the radial portion, the rib of the upper bearing cap radially surrounding the annular rib of the lower support cap. The annular rib of the lower support cap also forms an additional barrier to protect the bearing.

The annular rib may extend from a radial portion of the lower support cap and projects axially upwards, or is flush, with respect to a free upper end of the lower ring of the bearing.

DETAILED DESCRIPTION OF THE INVENTION

The suspension thrust bearing device10represented onFIG. 1is adapted to be installed between a top retainer seat suitable of resting, directly or indirectly, in an element of a chassis of the motor vehicle, and a suspension spring.

The device10, with an axis12, comprises an upper bearing cap14, a lower support cap16, and a rolling bearing18axially interposed between the caps14,16. The caps14,16are mounted in direct contact with the rolling bearing18without the interposition of an intermediate element.

As will be described later, the upper bearing cap14is designed to prevent intrusion of pollutants towards the rolling bearing18.

The upper bearing cap14may consist in one part, for example from plastic material, such as polyamide PA6.6which may or may not be reinforced with glass fibers.

The upper bearing cap14comprises a radial portion14a, an annular axial inner skirt14b, and an annular axial outer skirt14cradially surrounding the inner skirt14b. The radial portion14aprovides an upper surface15intended to face the top retainer seat, and an opposite lower surface17in contact with the rolling bearing18. The upper and lower surfaces15,17define the thickness of the radial portion14a. In the illustrated example, the radial portion14ahas a stepped shape.

The outer skirt14cradially surrounds the lower support cap16. The inner and outer skirts14b,14cextend axially downwards from the radial portion14a. In the illustrated example, the outer skirt14cextends a large-diameter edge of the radial portion14a. The inner skirt14bextends a small-diameter edge of the radial portion14a.

The upper bearing cap14further comprises a plurality of inner hooks14darranged on the inner skirt14band extending radially outwards. The hooks14dextend from the outer surface of the inner skirt14bradially outward in the direction of the lower support cap16. In the illustrated example, the hooks14dare arranged on the lower end of the inner skirt14b. In the illustrated example, the hooks14dare spaced relative to one another in the circumferential direction. Alternatively, an annular hook may be provided on the outer surface of the skirt14b.

The rolling bearing18is entirely located radially between the skirts14b,14cof the upper bearing cap. The rolling bearing18comprises an upper ring20in contact with the upper bearing cap14, a lower ring22in contact with the lower support cap16, and one row of rolling elements24, here balls, arranged between raceways formed on the rings. In the illustrated example, the rolling bearing18is of the oblique contact type to absorb both the radial forces and the axial forces exerted on the device.

The upper ring20and the lower ring22of the rolling bearing are made of a thin metal sheet, which has been stamped or rolled so as to define toroidal raceways for the rolling elements24between the two rings. The upper ring20is in contact with the lower surface17of the radial portion14aof the upper bearing cap. The lower ring22is in contact with an upper surface of the lower support cap16. The rolling bearing18also comprises a cage (not referenced) between the upper and lower rings20,22so as to maintain a regular circumferential spacing between the rolling elements24.

The lower support cap16may consist in one part, for example from plastic material, such as polyamide PA6.6which may or may not be reinforced with glass fibers.

The lower support cap16comprises an annular radial portion28in the form of a plate, and an annular axial skirt30which extends a small-diameter edge of the radial portion28. The skirt30extends axially on the side opposite to the upper bearing cap14and the rolling bearing18. The skirt30allows centering of the suspension spring. This centering is achieved by the outer surface of the skirt30. The radial portion28provides a lower annular radial surface28adelimiting a bearing surface for the suspension spring, and an upper surface28bin contact with the lower ring22of the bearing and of complementary form. A free upper end of the lower ring22axially protrudes with respect to the radial portion28.

The lower support cap16also comprises a plurality of inner hooks32arranged on the radial portion28and extending radially inwards. The hooks32extend from the bore of the radial portion28radially inward in the direction of the inner skirt14bof the upper bearing cap. The hooks32are spaced apart from each other in the circumferential direction, preferably regularly. Alternatively, the lower support cap16may comprise one annular inner hook, i.e. which is continuous in the circumferential direction.

The hooks32are disposed axially above the hooks14dof the inner skirt14bof the upper bearing cap. The hooks14dhave an outer diameter higher than the inner diameter of the hooks32so as to be able to interfere diametrically with the hooks32in the case of relative axial displacement of the bearing cap14and the support cap16. The hooks14dof the upper bearing cap form axial retention means cooperating with complementary axial retention means of the support cap16formed by the hooks32.

Otherwise, the hooks14d,32form narrow passageways in order to prevent the intrusion of foreign matter radially between the internal skirt14bof the upper bearing cap and the bore of the skirt30of the lower support cap.

The lower support cap16further comprises an annular flange34extending towards the outer skirt14cof the upper bearing cap while remaining radially spaced apart from the outer skirt. More generally, the flange34remains spaced apart from the upper bearing cap14.

The flange34is located radially slightly away from the bore of the outer skirt14cof the upper bearing cap to form a labyrinth sealing portion. An annular radial labyrinth seal (not referenced) is formed between the flange34and the outer skirt14cof the upper bearing. For instance, the radial gap between the flange34and the outer skirt14ccap may be less than 2 mm, and for instance comprised between 1 mm and 1.4 mm, and notably equal to 1.2 mm.

The flange34protrudes outwards from the radial portion28of the lower support cap. The flange34extends outwards from the outer surface of the radial portion28. The flange34extends radially. The flange34has a lower radial surface34aand an opposite upper radial surface34b. The lower and upper surfaces34a,34bdefine the thickness of the flange34. The lower and upper surfaces34a,34bextend radially from the outer surface of the radial portion28. The upper surface34bof the flange is oriented axially towards the radial portion14aof the upper bearing cap.

The lower support cap16further comprises an annular radial protrusion36extending radially outwards from the radial portion28. The protrusion36protrudes outwards from the outer surface of the radial portion28.

The protrusion36extends below the outer skirt14cof the upper bearing cap. In the illustrated example, the protrusion36extends radially outwards beyond the outer skirt14c. The protrusion36extends radially the lower radial surface28aof the radial portion delimiting the bearing surface for the suspension spring.

In the illustrated example, the lower support cap16also comprises an annular rib40extending axially from the radial portion28towards the radial portion14bof the upper bearing cap. The rib40extends from the upper face of the radial portion28. The rib40remains axially spaced apart from the lower surface17of the radial portion. The upper surface of the rib40forms the uppermost face of the lower support cap16.

The rib40radially surrounds a free upper end of the lower ring22of the bearing. In the illustrated example, the rib40is flush with respect to the free upper end of the lower ring22. Alternatively, the rib40may project axially upwards with respect to the free upper end of the lower ring22while remaining axially spaced apart from the radial portion14bof the upper bearing cap. In another variant, the lower support cap16may be deprived of the rib40. In this case, the upper face of the radial portion28forms the uppermost face of the lower support cap16.

As previously mentioned, the upper bearing cap14is designed to prevent intrusion of pollutants towards the rolling bearing18. The upper bearing cap14comprises an annular rib42extending axially towards the flange34of the lower support cap. The rib42extends from the radial portion14aof the upper bearing cap. The rib42protrudes from the lower surface17of the radial portion14a. The flange34extends radially outwards beyond the rib42.

The rib42remains axially spaced apart from the flange34of the lower support cap. The rib42extends axially towards the upper surface34bof the flange while remaining axially spaced apart from this surface. The rib42is located axially slightly away from the upper surface34bof the flange to form a labyrinth sealing portion. An annular axial labyrinth seal44is formed between the rib42and the upper surface34bof the flange. For instance, the axial gap between the rib42and the upper surface34bmay be less than 2 mm, and for instance comprised between 1 mm and 1.4 mm, and notably equal to 1.2 mm.

The rib42is radially located between the outer skirt14cof the upper bearing cap, and between the bearing18and the rib40of the lower support cap. The rib42radially surrounds the bearing18and the rib40.

The rib42has a lower surface42aaxially facing the upper surface34bof the flange. In the illustrated example, the lower surface42aextends radially. The lower surface42ais axially offset downwards with respect to the upper surface of the rib40forming the uppermost face of the lower support cap16. The lower surface42ais axially offset downwards with respect to the outer diameter of the rolling bearing18. In the illustrated example, the lower surface42ais axially offset downwards with respect to the free upper ends of the lower and upper rings22,20.

In the illustrated example, the rib42is located radially slightly away from the rib40. An annular radial labyrinth seal (not referenced) is formed between the ribs40,42. For instance, the radial gap between the ribs40,42may be less than 2 mm, and for instance comprised between 1 mm and 1.4 mm, and notably equal to 1.2 mm. In an alternative example, the radial gap between the ribs40,42may be filled by grease.

The rib42of the upper bearing cap forms a vertical barrier arranged radially between the outer skirt14cand the rolling bearing18to protect the bearing. With the rib42, the ingress of pollutant into the rolling bearing18is limited. The rib42also limits any splashes of water directed towards the rolling bearing18.

Otherwise, the flange34of the lower support cap forms a deflector against which is broken the water flow thrown up in the direction of the rolling bearing18.

The example shown onFIG. 2, in which identical parts are given identical references, differs from the first example in that the upper surface34bof the flange34of the lower support cap extends obliquely downwards. The upper inclined surface34bextend obliquely downwards from the outer surface of the radial portion28. This facilitates the circulation of the water by gravity outside of the device.

The example shown onFIG. 3, in which identical parts are given identical references, differs from the first example in that the flange34of the lower support cap extends obliquely downwards. Each of the lower and upper surfaces34a,34bof the flange are inclined. The lower and upper inclined surfaces34a,34bextend obliquely downwards from the outer surface of the radial portion28.

In a radial plane of the device as shown onFIG. 3, the lower inclined surface34aforms an angle with the axis12of the device which may be preferably comprised between extending 45° and 65°. In the illustrated example, the upper inclined surface34bof the flange extends parallel to the lower inclined surface34a.

In this example, the rib42has a lower inclined surface42aaxially facing the upper inclined surface34bof the flange which extends parallel to this upper inclined surface34b. Accordingly, the axial gap44between these surfaces42a,34bis constant. Alternatively, the lower surface42aof the rib may have other shape. For example, the lower surface42amay extend radially.

In the illustrated examples, the thrust bearing device comprises an angular contact rolling bearing provided with one row of balls. The thrust bearing device may comprise other types of rolling bearing, for example bearings having four points contacts and/or with at least double rows of balls. The rolling bearing of the device may comprise other types of rolling elements, for example rollers. In another variant, the bearing of the device may also be a sliding bearing having no rolling elements.