Vehicle suspension stop formed by bearing comprises spring support dish, elastic support block, bearing comprising upper and lower bushes located in upper and lower annular covers

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Suspension stop device.

The present invention relates to the field of suspension stops used in particular on motor vehicles in the telescopic suspension struts of the steered wheels.

A suspension stop generally comprises an upper ring and a lower ring between which are arranged rolling elements, in the form of balls or rollers.

A suspension stop is generally arranged in the upper part of the suspension strut, between a lower metal cup, also serving as a support seat for a suspension spring, and an upper element integral with the body of the vehicle. The spring of the suspension device is installed around the rod of the shock absorber piston, the end of which is secured to an elastic support block. The suspension thrust bearing allows a rotational movement between the spring support cup, movable in rotation, and the elastic support block which is fixed to the vehicle body. The relative angular movement between the spring support cup and the elastic block results from a deflection of the steering wheel and / or the compression of the suspension spring.

The suspension stopper also makes it possible to transmit the axial forces between the spring and the vehicle body.

From document FR 2 779 096, a suspension stop device is known, the bearing of which comprises an upper ring disposed inside a cover in contact with the elastic support block and a lower ring directly in contact with the support cup. The bearing comprises a cage provided with sealing lips to ensure the sealing of the bearing.

However, the sealing of the bearing thus obtained is not satisfactory. In fact, the suspension thrust bearings are located under the body of the vehicle and in the immediate vicinity of the wheels which project, in particular in rainy weather, polluting elements liable to enter the bearing.

Pollution of the bearing by external elements can over time impair the proper functioning of the bearing.

The subject of the invention is a very tight suspension thrust bearing, while remaining compact, axially and radially.

The invention proposes a suspension thrust bearing making it possible to transmit both axial and radial forces, while ensuring good distribution of the forces.

Finally, the invention proposes a suspension thrust bearing with a high level of sealing, which can be easily assembled, cannot be dismantled, and has a low manufacturing cost.

A suspension stop device for a vehicle, according to the invention, is of the type comprising an angular contact bearing forming a stop, a support cup for a spring, and an elastic support block, the bearing being arranged between the cup d 'support and the resilient support block integral with the vehicle frame. The bearing comprises an upper ring disposed in an annular upper cover forming an interface between said upper ring and the elastic block with which the upper cover is in contact, a lower ring, and rolling elements arranged between the races of the bearings of the upper and lower rings. . The suspension stop device comprises an annular lower cover forming an interface between the lower ring and the bearing cup with which the lower cover is in contact. The lower and upper covers each comprise a thick portion and a thin portion, the thin portion of one cover lying axially opposite the thick portion of the other cover, the lower and upper rings resting on the thick portions of the covers. lower and upper covers forming an angular contact bearing.

The arrangement of a thick portion facing a thin portion makes it possible to obtain an oblique contact bearing of reduced axial and radial size. The particular shape of the hoods comprising a thick portion and a thin portion allows a good distribution of the forces of a hood towards the bearing cup or of a hood towards the elastic support block, while facilitating the formation on the hoods of sealing means and / or the insert seal arrangement, to protect the suspension thrust bearing effectively.

Advantageously, one ring has an outer diameter substantially equal to the inner diameter of the other ring, so that the lower and upper rings can be obtained from the same blank in order to reduce the manufacturing cost thereof. Such a ring configuration easily makes it possible to obtain an angular contact bearing operating under good conditions of use.

Preferably, the ratio between the inner diameter of one outer ring and the outer diameter of the other ring is between 1 and 1.05. Depending on the orientation of the angular contact of the bearing, the upper ring is the ring with the largest average diameter, or the lower ring is the ring with the largest average diameter.

In a preferred embodiment, the upper and lower covers define an interior space where the upper and lower rings are located, the upper and lower covers comprising sealing means for sealing the interior space. The lower cover cooperates with the upper cover to form an interior space in which the bearing of the suspension stop device is located, which is thus protected. The sealing means of the upper and lower cowls cooperating with each other make it possible to ensure that the bearing is protected against the introduction of external polluting elements.

In one embodiment, a cover comprises a skirt extending axially in the direction of the other cover and radially limiting the interior space, while forming a narrow sealing passage with the other cover. The presence of the skirt makes it possible to close radially, at the inner or outer periphery, the inner space defined between the upper and lower cowls. The skirt forms a sealing means cooperating with the other cover to ensure the sealing of the interior space, by narrow radial and / or axial passage.

Preferably, a cover comprises means for axial retention with the other cover. Thus, a compact and non-removable assembly is obtained which can easily be handled without the risk of being accidentally dismantled by an operator.

In one embodiment, a cover comprises a radially elastic lip extending in the direction of a skirt of the other cover, forming a narrow passage and cooperating with a radial bead of the skirt to allow axial movement in a full direction. by preventing reverse axial movement. The lip cooperates with the skirt to provide a means of sealing the interior space. The skirt cooperates with the radial bead to provide an axial holding means between the upper cover and the lower cover. The skirt therefore fulfills a dual function of axial retention and sealing, which can be produced at low cost, and allows easy mounting of the suspension thrust bearing, and ensuring that the suspension thrust bearing cannot be accidentally removed.

To further improve the sealing of the bearing, the suspension stop device may comprise a seal disposed on a cover, for example in an annular rib, and having a lip in contact with a radial portion of the ring disposed on the 'other cover, or with the other cover. Optionally, each cover may include a seal cooperating with the ring disposed on the other cover or directly with the other cover. Thus, a seal provides improved sealing, the sealing means between the upper and lower covers allowing additional sealing.

Advantageously, a seal is overmolded on a cover by injection or molded at the same time as said cover by bi-injection.

The invention also relates to a method of manufacturing a bearing comprising a lower ring and an upper ring, in which two rings provided with toroidal portions are formed in a thin annular cup comprising surfaces having a concave profile in cross section, said surfaces being able to form raceways, a ring having an internal diameter substantially equal to the external diameter of the other ring, the rings being connected, the rings are separated, the groove radius is reduced by at least one ring and / or the internal diameter of the ring of larger diameter.

This manufacturing process can easily be applied to a hanger stop device: the rings are secured with lower and upper annular covers, the rolling elements are placed between the rings to form a suspension thrust bearing, the bearing is placed between a support cup of a spring and an integral elastic support block of the vehicle chassis, the upper cover forming an interface between said upper ring and the elastic block with which it is placed in contact, the lower cover forming an interface between the lower ring and the bearing cup with which it is placed in contact, each cover comprising a thick portion and a thin portion, the thin portion of a cover lying axially opposite the thick portion on the other cover, the lower and upper rings bearing against the thick portions of the lower and upper covers, forming an oblique contact bearing. The rings easily allow the manufacture of an angular contact bearing accepting axial and radial forces.

The present invention and its advantages will be better understood by studying the detailed description of embodiments taken by way of non-limiting examples and illustrated by the appended drawings, in which:

FIG. 1 is a view in axial section of a suspension thrust bearing in the mounted state;

FIG. 2 is a view of the suspension thrust bearing according to FIG. i;

FIG. 3 is a variant of a suspension thrust bearing according to FIG. 2; and

FIGS. 4 to 6 illustrate a method of manufacturing two rings used in the suspension thrust bearings according to FIGS. 1 to 3.

In Figure 1, a shock absorber comprises a cylinder not shown in which can slide a piston whose rod 1 is linked by its upper end to an elastic support block 2 which comes to bear in an element of the frame 3 forming a seat by being secured. with this one. The elastic support block 2 comprises an annular inner connecting element 4 made in two parts 4a and 4b on which the end of the rod 1 of the shock absorber piston is mounted by means of a nut 5, a connecting element annular outer 6 serving for connection with the frame 3, an annular upper cup 7 serving as a support seat for the thrust bearing 8, a rubber block 9 adhered to the surface of these three parts and forming a connection between them with filtration of vibrations.

The outer connecting element 6 is fixed to the frame 3, for example by screwing or bolting. The upper cup 7 is disposed axially at the level of the internal connecting element 4, but has a larger diameter. We also see the suspension spring 10, the upper end of which rests on an annular lower cup 11 which, in turn, rests on the thrust bearing 8.

The upper cup 7 comprises a radial portion 7a and a cylindrical axial portion 7b extending from the portion of larger diameter of the radial portion 7a. The upper surface of the radial portion 7a and the outer surface of the cylindrical portion 7b are in contact with the rubber block 9 of the elastic support block 2.

The lower cup 11 comprises a groove 11a in which the end of the spring 10 bears, a radial portion 11b extending radially inward from the groove 11a, and a cylindrical portion 11c extending axially towards the interior. upper cup 7 from the free inner edge of the radial portion 11b

The suspension stop 8, better visible in FIG. 2, comprises an upper ring 12, a lower ring 13, between which are housed rolling elements 14, here balls, kept circumferentially regularly spaced by a cage 15 made of synthetic material. The upper 12 and lower 13 rings are formed from sheet steel by cutting and stamping.

The upper ring 12 comprises a toroidal portion 12a having in cross section a concave quarter-circle internal profile and capable of forming a toroidal raceway for balls, said toroidal portion 12a being extended outwardly by a radial portion 12b, extending from a lower edge of the toroidal portion 12a.

The lower ring 13 comprises a toroidal portion 13a having in cross section a concave internal profile in a quarter circle and capable of forming a toroidal raceway for balls, said toroidal portion 13a being extended inwardly by a radial portion 13b, extending from an upper edge of the toroidal portion 13a. The inside diameter of the upper ring 12 is substantially equal to the outside diameter of the lower ring 13.

The suspension stopper 8 comprises an annular upper cover 16 and an annular lower cover 17 made of synthetic material such as a polyamide filled with glass fibers. The top cover 16 comprises a thick peripheral portion 18 extended radially inwardly by a thin radial portion 19 of thinner thickness, from the upper end of the thick portion 18.

The thick portion 18 comprises a radial surface 18b oriented towards the lower cover 17 and a toroidal inner surface 18a having in cross section a concave profile oriented towards the lower cover 17 and radially inward, the inner surface 18a connecting the thick portion 18 to the thin portion 19. The thick portion 18 is of thickness decreasing radially inwardly. The top cover 16 includes an upper radial surface 16a and an outer cylindrical surface 16b connected by a rounded chamfer 16c.

The upper cover 16 comprises an inner skirt 20 extending axially in the direction of the lower cover 17 from the region of lesser diameter of the thin portion 19. The cover 16 also comprises an outer skirt 21 extending axially in the direction of the cover. lower 17 from the area of ​​greatest diameter of the thick portion 18.

The thick portion 18 matches the shape of the upper ring

12, the convex outer surface of the toroidal portion 12a bearing against the toroidal inner surface 18a of the thick portion 18, and the substantially radial portion 12b projecting onto the radial surface 18b of the thick portion 18.

The lower cover 17 comprises a thick portion 22 of smaller diameter extended radially outwards, and from a lower edge of the thick portion 22, by a thin radial portion 23 of smaller thickness. The thick portion 22 comprises an outer surface 22a having in cross section a concave profile oriented outwardly, the outer surface 22a connecting the thick portion 22 to the thinner portion 23. The thick portion 22 is of thickness decreasing radially outwards. The lower cover 17 comprises a lower radial surface 17a and a cylindrical inner surface 17b connected by a rounded chamfer 17c.

The thick portion 22 matches the shape of the lower ring

13, the inner surface with a concave profile of the toroidal portion 13a resting on the outer surface 22a of the thick portion, the radial portion 13b slightly covering the thick portion 22 of the lower cover 17.

The lower cover 17 comprises an annular rib 24 extending axially in the direction of the upper cover 16, from the thick portion 22. The diameter of the annular rib 24 is greater than the diameter of the inner cylindrical surface 17b, being less than the diameter. diameter of the area of ​​smallest diameter of the outer surface 22a. The lower cover 17 comprises a radial surface 22b located between the cylindrical surface 17b and the annular rib 24, and a radial surface 22c located between the annular rib 24 and the upper edge of the outer surface 22a. The radial portion 13b of the lower ring 13 covers the radial surface 22c by coming radially close to the annular rib 24.

The inner skirt 20 of the top cover 16 extends axially near the radial surface 22b forming a narrow radial passage. The outer skirt 20 surrounds the annular rib 24 forming a narrow axial passage. Thus, the skirt 20 cooperates with the annular rib 24 to form a sealing means by narrow passage between the lower cover 17 and the upper cover 16.

The inner skirt 20 has an inner diameter substantially equal to the inner diameter of the thick portion 22 of the lower cover 17.

The cover 17 comprises a radially resilient lip 25, extending obliquely outwardly from the surface of an annular bead 25a formed at the larger diameter end of the thinner portion 23, and coming into contact. or near the inner surface of the outer skirt 21 of the top cover 16. The lip 25 extends radially outwards and axially on the side opposite the top cover 16. The lip 25 makes it possible to produce a sealing means between the upper 16 and lower 17 cowls by narrow passage or possibly by frictional contact.

The outer skirt 21 comprises at its axial end opposite the upper cover 16 an annular bead 26 extending radially inward. The annular bead 26 allows passage axially in one direction of the lip 25 of the lower cover 17 which deforms radially inwardly, and prevents a reverse axial movement of the lip 25. The lower cover 17 can thus be axially secured with the top cover 16. The bead 26 comprises a frustoconical surface 26a oriented on the side opposite to the upper cover 16 facilitating the deformation of the lip 25 during the introduction of the lower cover 17 into the upper cover 16. The bead 26 comprises a frustoconical surface 26b oriented towards the cover. 16, on which the lip 25 bears if the lower cover 17 tends to move away axially from the upper cover 16, preventing axial movement away from the lower 17 and upper 16 covers.

The lip 25 has a dual sealing and axial holding function. The lip 25, integral with the lower cover 17, can easily be obtained at the same time as the lower cover 17. The lip 25 allows easy assembly and axial retention, possibly with axial play.

The suspension stop 8 comprises a seal 27 comprising a heel 28 arranged and fixed in an annular groove 29 of the lower cover 17 and a lip 30 extending radially outwardly and axially towards the upper cover 16, and coming from in frictional contact with the radial portion 12b of the upper ring 12. The heel 28 of the seal 27 is located axially opposite the rolling elements 14, surrounding the free edge of the toroidal portion 13a of the lower ring 13.

The use of an upper cover 16 and a lower cover 17 makes it possible to form an interior space delimited axially by the upper cover 16 and the lower cover 17 and radially by the inner 20 and outer 21 skirts, in which the rings 12, 13 as well as the rolling elements 14. It is easy to seal the interior space.

The covers 16, 17 forming an interface respectively between the upper cup 7 and the upper ring 12, and between the lower ring 13 and the lower cup 11, allow transmission and distribution of axial and radial forces between the upper 7 and lower cups. II. Returning to FIG. 1, the upper cover 16 bears axially by its thick 18 and thin 19 portions on the annular portion 7a of the upper cup 7, and in contact by its thick portion 18 with the cylindrical portion 7b. The thick portion 18 transmits radial and axial forces to the upper cup 7. The thin portion 19 mainly transmits axial forces to the upper cup 7. Likewise, the lower cover 17 bears axially by its thick 22 and thin 23 portions. on the annular portion 11b of the lower cup, and in radial bearing, by its thick portion 22, on the axial portion 11c.

Optionally, the upper cover 16 can be placed directly in contact with the rubber block 9 without using an intermediate upper cup 7.

The lip 25 cooperating with the annular bead 26 forms an axial retaining means between the upper cover 16 and the lower cover 17 so as to obtain a suspension stop bearing 8 which is easy to assemble and cannot be removed, so that it can be handled. by an operator without risk of accidental dismantling.

To improve the tightness of the suspension thrust bearing 8, and as shown in FIG. 3, provision can be made to have a second seal 31 having a heel 32 disposed radially in the region of smaller diameter of the thin portion 19, fixed in an annular groove 33 formed between the inner skirt 20 and an annular bead 19a of the thinner portion 19 of the top cover 16, and having a lip 34 extending obliquely, axially in the direction of the lower cover 17 and radially outwards, and coming into frictional contact with the radial portion 13b of the lower ring 13. Thus, the seals 31, 27 allow effective sealing, improving the sealing already provided by the sealing means of the upper 16 and lower 17 covers.

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The presence of the thin portions 19, 23 extending radially, and axially opposite the thick portions 22, 18, facilitates the fixing of the additional seals 31, 27.

In the embodiment illustrated by Figure 3, the radial surface 22b is formed at a level offset axially downward from the radial surface 22c, so that the outer skirt 21 is more extended axially, the annular rib 24 being less extended axially to allow the passage of the lip 34, while retaining a narrow passage of dimensions similar to the embodiment illustrated above.

In the previous embodiments, the upper 16 and lower 17 covers can easily be obtained by molding. Advantageously, the seals 27, 31 can be overmolded directly on the upper and lower covers 16, 17 or be manufactured by bi-injection molding at the same time as said covers 16,17.

The outside diameter of the lower ring 13 is substantially equal to the inside diameter of the upper ring 12. This particular configuration makes it possible to obtain the upper 12 and lower 13 rings from the same blank, as illustrated in FIGS. 4 to 6. .

In FIG. 4, an annular cup 35 made of thin sheet metal, shaped for example by cutting and stamping, comprises two future rings 36, 37 connected together and symbolically separated in FIG. 4 by lines 38. The ring 36 of smaller diameter comprises a toroidal portion 39, the outer surface 39a of which has in cross section a concave profile substantially in a quarter of a circle, and a radial portion 40 extending inwardly from the region of lesser diameter. diameter of the toroidal portion 39.

The ring 37 extends from the free edge of the ring 36 opposite to the radial portion 40. The ring 37 comprises a toroidal portion 41 whose inner surface 41a has in cross section a concave profile substantially in a quarter circle, and comprises a radial portion 42 extending outwardly from the free edge of the ring 37 opposite to the ring 36.

The surfaces with a concave profile 39a, 41a of the toroidal portions 39, 41 of the rings 36, 37 are able to form raceways for the rolling elements of a suspension thrust bearing, for example balls.

To obtain the lower and upper rings, the rings 36, 37 are separated, for example by means of a cutting punch which shears the material of the cup 35 in a circle whose center passes through the axis of revolution of the cup. cup 35 and radially delimited by the lines 38. A ring 36 is obtained with an outside diameter substantially equal to the inside diameter of the other ring 37. The concave profile surface 39a has a groove radius RI materialized on a dotted circle 43.

FIG. 6 illustrates the ring 37 after an additional shaping operation, during which the groove radius of the ring 37 is reduced to obtain a groove radius R2 less than RI, shown on a dotted circle 44. It is possible, during the same operation, to slightly reduce the internal diameter of the ring 37 so that the ring 37 projects radially inwards beyond the pitch radius of the rolling bearing formed using the ring 37, to ensure that the free edge of the ring 37 does not damage the rolling elements in the event of significant axial force. An identical operation can be carried out on the ring 36.

A groove radius R2 of the ring 37 identical to the groove radius of the ring 36 is preferably adopted on the finished rings, the two groove radii being slightly greater than the radius of the balls of the bearing. Preferably, the ratio between the final inside diameter of the ring 36 and the final outside diameter of the ring 37 is between 1 and 1.05.

Returning to Figures 1 to 3, and using the rings 36 and 37 whose inner and outer diameters have been modified, to form the rings 13 and 12, it is ensured that the free end of the toroidal portion 12a of the upper ring 12 and the free end of the toroidal portion 13a of the lower ring 13 will not damage the rolling elements 14 in the event of transmission of a large axial force by the suspension thrust bearing 8.

The method of manufacturing the suspension bearing 8 makes it possible to obtain the upper and lower rings from the same blank, which makes it possible to reduce the manufacturing cost of the suspension thrust bearing. In addition, by a simple additional operation, the groove radius of the lower ring and / or the upper ring is reduced, and the elements are held in good condition during the transmission of significant axial forces.

Thanks to the invention, a suspension thrust bearing is obtained comprising two covers defining an interior space, the sealing of which is ensured by sealing means of the mutually cooperating covers as well as by attached seals. The particular structure of the covers makes it possible to obtain a bearing of reduced axial size, facilitating the arrangement of attached seals. The suspension thrust bearing makes it possible to transmit both axial and radial forces, the lower and upper cowls allowing a good distribution and better transmission of the forces from the lower support cup to the upper support cup, and vice versa .