WO2016030638A1

WO2016030638A1 - Bump stop comprising a moving sealing element

Info

Publication number: WO2016030638A1
Application number: PCT/FR2015/052288
Authority: WO
Inventors: Anthony CAMPART
Original assignee: Ntn-Snr Roulements
Priority date: 2014-08-28
Filing date: 2015-08-28
Publication date: 2016-03-03
Also published as: FR3025138A1; FR3025138B1

Abstract

Bump stop comprising a moving sealing element. The invention relates to a motor vehicle bump stop, said stop comprising an upper coupling (1), a lower coupling (2) and roller bodies disposed between said couplings to allow their relative rotation, said couplings being arranged to form between them at least one annular sealing chamber (14b), said stop further comprising a sealing element (16) having two segments (16a, 16b) which are mounted so as to move inside said chamber in relation respectively to a first (22) and a second (23) bearing face formed respectively on a coupling (1, 2), the first segment (16a) being mounted to slidingly seal on the first bearing face (22), said sliding seal being arranged to enable a reversible movement of the sealing element (16) to a position in which the second segment (16b) comes into sealed contact against the second bearing face (23).

Description

Suspension stopper comprising a movable sealing element

The invention relates to a motor vehicle suspension stop, particularly intended to be integrated into a telescopic strut of a motor vehicle steering wheel.

The invention applies to a suspension stop comprising a fixed upper cup intended to be associated with the vehicle body, a lower rotating cup having a support for the suspension spring and rolling bodies arranged between said cups to allow their rotation. relative.

To prevent, on the one hand, the leakage of the lubricant present in the running space and, on the other hand, the contamination of said space with external pollutants, the use of seals comprising a flexible sealing element which is associated or integrated with one of the cups to be in rubbing contact on the other cup.

This embodiment has the disadvantage of inducing a friction torque during the relative rotation of the cups, which is detrimental to the use of the stop in the mounting of a steering wheel.

To solve this problem, the document WO-2009/019340 proposes a motor vehicle suspension stop which comprises an upper cup, a lower cup and rolling bodies arranged between said cups to allow their relative rotation, said cups being arranged to present between they at least one annular sealing chamber, said abutment further comprising a sealing element which is disposed in said chamber to be in rubbing contact on each of the cups and which is mounted to move relative to at least one cup. Thus, a compromise between the sealing function and the induced torque is obtained particularly satisfactorily, even in case of deformation of the abutment under the effect of the forces undergone. However, the suspension stop may be subjected to projections of external pollutants, for example jets of water and / or mud, especially when the vehicle is used in bad weather on muddy ground and / or covered with puddles. water. In this case, the pollutants can be projected at high speed against the sealing element which, being mobile, can move in the sealing chamber causing the breaking of the rubbing contact and the entry of pollutants into said chamber. The invention aims to improve the prior art by proposing a suspension stop in which the seal is provided by at least one sealing element which is mounted to move in the sealing chamber so as to be able to temporarily reinforce the tightness. in particular avoiding the entry of external pollutants projected on said element.

For this purpose, the invention proposes a motor vehicle suspension stop, said stop comprising an upper cup, a lower cup and rolling bodies arranged between said cups to allow their relative rotation, said cups being arranged to form between them at least an annular sealing chamber, said abutment further comprising a sealing member having two segments which are movably mounted in said chamber with respect to respectively a first and a second span respectively formed on a cup, the first segment being slidably mounted sealing on the first span, said sealed slip being arranged to allow a reversible displacement of the sealing member to a position in which the second segment comes into sealing contact against the second range. Other features and advantages of the invention will appear in the description which follows, made with reference to the appended figures, in which:

- Figure 1 shows in axial section a suspension stop according to one embodiment of the invention;

- Figure 1a is an enlarged partial view showing more particularly the mounting of the inner sealing member of the abutment of Figure 1.

In this description, the terms of positioning in space are taken with reference to the axis of rotation A of the suspension abutment (vertical in the figures). In particular, the term "inside" relates to a disposition close to this axis A and the term "outside" relates to a distance arrangement of this axis A. Moreover, the terms "higher" and "lower" are relative. at the disposal of the stop as shown in the figures. A wheel of a motor vehicle, including a steering wheel, is mounted on the chassis via a strut that allows the suspension of the body relative to the ground. For this purpose, the strut conventionally comprises a damper, a suspension spring and a suspension stop on which the spring bears.

In relation to the figures, a suspension abutment is described below which comprises a fixed upper cup 1 intended to be associated with the vehicle body, a lower rotary cup 2 comprising a support 3 for the suspension spring and rolling bodies. disposed between said cups to allow their relative rotation about an axis A. Thus, when the spring is biased in compression and relaxation, the winding of the turns of the latter on themselves is modified, which causes the rotation of the lower cup 2. In addition, the steering of the wheels also induces a rotation of the lower cup 2.

In the embodiment shown, the upper and lower cups 1 each comprise a washer 5, 6, in particular made of stamped sheet metal, which is provided with a rolling track respectively lower and upper for the rolling bodies.

More precisely, the upper washer 5 has an axial inner stiffening surface 7, and an axi-radial bearing surface 8 on the lower part of which the upper raceway is formed. The lower washer 6 comprises an internal axial stiffening bearing surface 9, and an axi-radial bearing surface 10 on which the lower raceway is formed opposite the upper raceway to form an oblique-contact raceway of the rolling bodies.

The abutment further comprises two trim parts January 1, 12, in particular made by molding a rigid thermoplastic material, for example polyamide type 6.6. These parts are respectively a lid 1 1 associated on the upper washer 5 to be interposed between the frame and said upper washer, and a support 12 associated under the lower washer 6, said support comprising the spring support 3. These parts dressing 1 1, 12 allow in particular a recovery of the forces of the spring and possibly those of the abutment.

In the embodiment shown, the cover 1 1 comprises an outer annular skirt 13a and an inner annular skirt 13b forming on one side of the support 12 respectively an outer annular chamber 14a and an inner annular chamber 14b between said cover and said support. In particular, the sealing chambers 14a, 14b are formed between the inner and outer diameters of the cover 1 1 and the support 12 and have a clearance so as to allow the rotation of the support 12 relative to the cover 1 1 without interference between those -this. To prevent, on the one hand, the leakage of the lubricant present in the running space and, on the other hand, the contamination of said space with external pollutants, each of the sealing chambers 14a, 14b comprises an element sealing 15, 16, in particular made of rigid thermoplastic material, for example polyethylene, polypropylene, polyamide 6, 6.6, 1 1 or 12.

The sealing elements 15, 16 have an annular geometry which can be made in one piece, for example by molding, each of said sealing elements having two segments which are movably mounted in a chamber 14a, 14b with respect to respectively a cup 1, 2.

According to one embodiment, at least one chamber 14a, 14b may contain a viscous substance to improve the sealing provided by the sealing element 15, 16. In particular, the substance may also have a lubricating function relative to the displacements of the sealing element 15, 16 in the chamber 14a, 14b. In the figures, the outer annular chamber 14a comprises a radial annular groove 17 which is formed in the lower cup 2, in particular on the outer diameter of the support 12. A first sealing element 15 is mounted to move in the groove 17 and, the opposite of said groove, is in rubbing contact on the upper cup 1, in particular on the lid January 1. Thus, the groove 17 allows the guiding of the sealing element 15 during its movements, while ensuring a sealed frictional contact of said element on the support 12 and on the lid January 1.

The outer annular chamber 14a is delimited by a bearing surface 18 formed on an inner surface of the outer skirt 13a. Moreover, the first sealing element 15 extends radially and comprises a first outer segment which is in frictional contact on the bearing surface 18, as well as a second inner segment which moves radially in the groove 17 in a direction normal to the bearing 18. Thus, in case of relative displacement of the lid 1 1 and the support 12, the bearing surface 18 induces a displacement force of the element 15 in the groove 17 which is optimized to limit the resulting torque. In particular, the groove 17 extends radially and the bearing surface 18 extends axially. In this embodiment, a radial clearance is formed between the diameters of the first sealing member 15 and the groove 17 so as to allow radial displacement of said sealing member in said groove. Furthermore, the first sealing element 15 has, at least at its second segment, a substantially similar section to that of the groove 17, namely rectangular in FIG.

According to one variant, a clearance can be formed between the outer peripheries of the first sealing element 15 and the internal groove 17. According to another variant, a sliding frictional contact can be made between the groove 17 and the second segment of the groove 17. element 15 which is arranged inside.

In the figures, the outer skirt 13a is provided with projections 20, the support 12 having a cavity 21 in which the said projections are arranged without interference so as to form a hook for holding the lid 1 1 on the support 12.

The inner annular chamber 14b is equipped with a second sealing element 16 whose two segments 16a, 16b are movably mounted in said chamber relative to respectively a first 22 and a second span 23 formed respectively on a cup 1, 2.

In particular, the second sealing element 16 is mounted in the inner chamber 14b so that its first segment 16a is sealingly mounted on the first bearing surface 22, said sealed slip being arranged to allow a reversible displacement of the sealing member 16 to a position in which the second segment 16b comes into sealing engagement against the second bearing surface 23.

Thus, when a projection of external pollutant comes into contact with the second element 16, said element is moved by leaktight sliding of its first segment 16a along the first surface 22, until the second segment 16b comes to be pressed against the second reach 23 to make a sealed contact and form dam to said projection of external pollutant. Moreover, after the projection of pollutant, the sealing member 16 is no longer constrained, and returns to its initial position by sealing slip of the first segment 16a along the first bearing 22. At the same time, the contact sealing between the second segment 16b and the second bearing 23 is broken so as not to induce friction torque between two projections.

As a result, the sealing element 16 is generally in frictional contact only against a cup 1, 2, in particular the lower cup 2, in order to limit the torque induced by the sealing function and, during a projection of pollutant in the chamber 14b, said element is put punctually in rubbing contact against the two cups 1, 2 to temporarily enhance the sealing of said chamber by blocking the entry of pollutant.

Thus, it is possible to combine the sealing function induced by the rubbing contact with the limitation of the torque induced by the possibility of displacement of the sealing element 16 with respect to at least one cup 1, 2. in case of deformation of the stop, in particular of the cover 1 1 relative to the support 12, a reduction of the clearance formed in the annular chamber 14b does not lead to an increase in the torque induced by the friction of the sealing element 16. in addition, this makes it possible to obtain a torque that is substantially constant and therefore controllable precisely over an extended operating range, and in particular with respect to the mechanical stresses that the suspension stop has to undergo in the context of its use.

According to a variant not shown, such a sealing member 16 could be mounted in the outer annular chamber 14a and the inner annular chamber 14b could be equipped with a sealing member 15 as described above. According to another variant, the two annular chambers 14a, 14b could each be equipped with such a sealing element 16. Insofar as the second sealing element 16 is rigid, the ends of the segments 16a, 16b can be arranged to improve the contact on the bearing surfaces 22, 23. For this purpose, in the embodiment shown, the end of each segment 16a, 16b has a rounded tip.

In the figures, the first 22 and second 23 bearings are formed respectively on the lower cup 2 and on the upper cup 1, more particularly on the support 12 (for the first reach 22) and on the cover 1 1 (for the second reach 23).

In particular, the second segment 16b and the second surface 23 are arranged to form a sealed contact along a generatrix G which is inclined relative to the axis of rotation A of the abutment.

To do this, the second sealing element 16 has an annular geometry whose section has an inclination with respect to the axis of rotation A, said inclination being in particular directed towards the inside, the first 16a and second 16b segments being formed on one end of said section respectively.

More specifically, the sealing member 16 has an outer end on which the first segment 16a is formed and an inner end bearing the second segment 16b. In addition, the first bearing 22 extends parallel to the axis of rotation A, and the second bearing 23 extends parallel to the inclination a forming a clearance J with the second segment 16b.

Thus, as shown in FIGS. 1, in the absence of projection on the sealing element 16, the second segment 16b is not in contact on the cup 1 while forming the clearance J as well as a radial clearance between the inner end of said element and the skirt 13b, said sets being arranged to form a sealing baffle between said element and the lid January. And, when a projection of external pollutant comes into contact with the sealing element 16, said element is reversibly displaced on a stroke corresponding to the clearance J by axial sliding upwards of the first segment 16a against the first bearing surface 22, the sealed contact being made in an inclined direction between the second segment 16b and the second bearing surface 23.

The inner annular chamber 14b has an opening 24 formed between the cups 1, 2, said opening having an orientation which is substantially perpendicular to the second sealing member 16.

Thus, any projection of external pollutant which enters through the opening 24 is directed substantially in this particular orientation of said opening, so as to strike perpendicularly the second sealing member 16 and cause its upward vertical displacement by sliding of its first segment 16a along the first span 22, until the second segment 16b comes to plead in sealing contact against the second bearing surface 23 to form a barrier to said projection.

The opening 24 is delimited by two projections 25, 26 belonging respectively to a cup 1, 2 to form a baffle, to form a dam designed to reduce the power of a pollutant projection entering through said opening.

In relation to the figures, the support 12 and the cover 1 1 respectively comprise a radial projection 26 and an axial projection 25 between which the opening 24 is formed. According to one embodiment, at least one projection 25, 26 may have a skirt which is connected to a bearing surface 22, 23.

In particular, the support 12 comprises an internal projection 27 which has an axial wall 28 from a lower edge of which the radial projection 26 extends, and a radial platform 29 which extends from an upper edge of said wall, the first bearing 22 extending axially from an outer edge of said platform. Advantageously, the projection 26 and the platform 29 can be slightly sloped to facilitate the evacuation of liquids and other pollutants.

The axial projection 25 extends from the lower end of the inner skirt 13b, the second span 23 extending at the inclination α from the upper end of said inner skirt. Thus, the skirt 13b and the second wall 23 form between them a housing 30 in which the second segment 16b comes into sealing contact. To improve the sealing of the contact between the second segment 16b and the second surface 23, the housing 30 may have a geometry complementary to the geometry of the inner end of the sealing element 16.

Insofar as the sealing elements 15, 16 are rigid, it is possible, to ensure the mounting of the stop, to provide said elements on the support 12, in particular by arranging the first element 15 in the radial groove 17 and the second member 16 on the first bearing 22, and then mounting said support on the lid 1 1 arranged upside down.

Moreover, to facilitate this assembly, the free edge of the outer skirt 13a and at least one projection 25, 26, in particular the axial projection 25, may have a chamfer 19, 31 on which the rounded end respectively of the first segment of the sealing member 15 and the second segment 16b of the sealing member 16 slides to be disposed correctly in the chamber 14a, 14b.

Claims

1. Motor vehicle suspension stop, said stop comprising an upper cup (1), a lower cup (2) and rolling bodies arranged between said cups to allow their relative rotation, said cups being arranged to form between them at least one annular chamber sealing member (14b), said stopper further comprising a sealing member (16) having two segments (16a, 16b) which are movably mounted in said chamber with respect to respectively a first (22) and a second (23) bearing formed on respectively a cup (1, 2), said stop being characterized in that the first segment (16a) is sealingly mounted on the first bearing surface (22), said sealed slip being arranged to allow a reversible displacement of the sealing member (16) to a position in which the second segment (16b) makes sealing engagement against the second bearing surface (23).

2. Suspension stop according to claim 1, characterized in that the second segment (16b) and the second surface (23) are arranged to form a sealed contact along a generatrix (G) which is inclined relative to the axis of rotation (A) of said stop.

3. Suspension stop according to claim 2, characterized in that the sealing element (16) has an annular geometry whose section has an inclination (a) with respect to the axis of rotation (A), both segments (16a, 16b) being formed on one end of said section, respectively.

4. Suspension stop according to claim 3, characterized in that the second bearing (23) extends parallel to the inclination (a) forming a clearance (J) with the second segment (16b), the sealing contact being performed by plating said second segment on said second span following the reversible displacement of the sealing element (16) on a stroke corresponding to said clearance.

5. Suspension stop according to any one of claims 1 to 4, characterized in that the first bearing (22) extends parallel to the axis of rotation (A).

6. Suspension stop according to any one of claims 1 to 5, characterized in that the first (22) and second (23) carried are formed respectively on the lower cup (2) and on the upper cup (1).

7. suspension stop according to any one of claims 1 to 6, characterized in that the upper cups (1) and lower (2) each comprise a washer (5, 6) which is provided with a raceway respectively lower and upper for the rolling bodies, said stopper further comprising two trim parts (1 1, 12), respectively a cover (1 1) associated on the upper washer (5) and a support (12) associated under the washer lower (6), the sealing chamber (14b) being provided between said cover and said support.

8. Suspension stop according to any one of claims 1 to 7, characterized in that it comprises a second annular sealing chamber (14a) in which a second sealing member (15) is disposed.

9. Suspension stop according to claim 8, characterized in that the second chamber (14a) comprises at least one annular groove (17) formed in a cup (2), the second sealing element (15) being movably mounted in said groove and, opposite said groove, being in rubbing contact on the other cup (1).

10. Suspension stop according to claim 9, characterized in that the groove (17) extends radially and the second sealing element (15) extends radially with a first segment which is in rubbing contact on the another cup (1) and a second segment which moves radially in said groove.

1 1. Suspension stop according to one of claims 1 to 10, characterized in that the sealing element (15, 16) is made of rigid thermoplastic material.

12. Suspension stop according to any one of claims 1 to 1 1, characterized in that the sealing chamber (14b) has an opening (24) formed between the cups (1, 2), said opening having an orientation which is substantially perpendicular to the sealing member (16).

13. Suspension stop according to claim 12, characterized in that the opening (24) is delimited by two projections (25, 26) belonging respectively to a cup (1, 2) to form a baffle.

14. Suspension stop according to claim 13, characterized in that at least one projection (25) has a chamfer (31).

15. Suspension stop according to claim 13 or 14, characterized in that at least one projection (25) has a skirt (13b) which is connected to a bearing surface (23).