WO2007010105A1

WO2007010105A1 - Assembly forming drive wheel bearing incorporating a secondary drive shaft

Info

Publication number: WO2007010105A1
Application number: PCT/FR2006/001552
Authority: WO
Inventors: James Perillat-Amede; Bernard Chaudier; Christophe Nicot
Original assignee: S.N.R. Roulements
Priority date: 2005-07-18
Filing date: 2006-06-30
Publication date: 2007-01-25
Also published as: EP1904755A1; FR2888529B1; FR2888529A1

Abstract

The invention concerns an assembly forming a roller bearing for a motor vehicle drive wheel, said assembly comprising a rotating hub (1) whereon the wheel is to be mounted, a stationary outer ring (5) of a ball bearing which is mounted on the hub (1) via running elements (4) so as to enable said assembly to be associated with the vehicle chassis, said hub including a bore wherein is arranged a three-ball-and-trunnion universal joint, said assembly further comprising a secondary drive shaft (14) which is fixed to the three-ball-and-trunnion universal joint, the inner end part of said secondary drive shaft being provided with a device for being reversibly coupled with an engine drive shaft (17).

Description

Driving wheel bearing assembly incorporating a secondary drive shaft

The invention relates to a rolling bearing assembly for a drive wheel of a motor vehicle.

Such assemblies are known which comprise a rotating hub on which the wheel is intended to be mounted, a fixed outer race of a bearing allowing the combination of the assembly to the chassis of the vehicle, and a tripod joint associated with the hub. The motor transmission shaft is associated with the tripod joint so as to drive the hub in rotation in the different phases of rolling of the wheel, in particular whatever the relative position of the wheel relative to the frame.

This embodiment, which integrates the combination of the wheel and the torque transmission in one piece, provides a compact, lightweight and robust, which is desirable given the efforts that apply to a wheel driving.

However, the prior art provides to associate the motor drive shaft directly to the tripod joint which is not fully satisfactory.

In particular, given the mechanical stresses applied, the tripod joint requires lubrication to ensure optimal operation thereof over time. However, with the assemblies presented above, this lubrication makes relatively complex assembly of the motor transmission shaft in the tripod joint, and the decoupling thereof.

In addition, given the size of the motor shaft, and its association with the output of the gearbox, the manipulation thereof for its direct association with the tripod joint is not easy. The invention aims to solve the problems of the prior art by providing a rolling bearing assembly in which the coupling of the motor shaft is not made directly on the tripod joint.

For this purpose, the invention proposes a rolling bearing assembly for a driving wheel of a motor vehicle, said assembly comprising a rotating hub on which the wheel is intended to be mounted, a fixed outer ring of a bearing which is mounted on the wheel. hub via rolling bodies so as to allow the combination of said assembly to the vehicle frame, said hub comprising a bore in which a tripod joint is disposed. The assembly further includes a secondary drive shaft which is attached to the tripod joint, the inner end portion of said secondary drive shaft being provided with a reversible coupling device with a motor drive shaft.

Thus, the assembly integrates a portion of the transmission function and makes reversible, at the integrated secondary transmission shaft, the coupling of the motor transmission shaft.

Other objects and advantages of the invention will become apparent from the following description, made with reference to the appended drawings, in which:

- Figure 1 is a longitudinal sectional representation of an assembly according to a first embodiment of the invention; FIG. 2 is a perspective representation of the assembly of FIG. 1;

FIG. 3 is a partial view of FIG. 1 showing the reversible coupling device in which a motor transmission shaft is coupled; - Figure 4 is a similar view of Figure 3 showing the reversible coupling device according to an alternative embodiment;

- Figures 4a and 4b are half sections respectively along lines AA and BB of Figure 5; FIG. 5 is a representation in longitudinal section of an assembly according to a second embodiment of the invention;

- Figures 6a to 6e are partial views of Figure 5 showing two arrangements of an angular encoder means in combination with three embodiments of the bearing seal;

FIG. 7 is a representation in longitudinal section of an assembly according to a third embodiment of the invention;

- Figures 8a to 8e are partial views of Figure 7 showing two arrangements of an angular encoder means in combination with two embodiments of the bearing seal.

With reference to FIGS. 1 and 2, a first embodiment of a rolling bearing assembly for a driving wheel of a motor vehicle is described.

The assembly comprises a rotating hub 1 on which the wheel is intended to be mounted. The hub is formed of an annular body having a central bore coaxial with the axis of rotation. On the outer part of the surface of the body, a radial flange 2 is formed, said flange being provided with orifices 3 forming means for fastening the wheel by screwing.

In the remainder of the description, the terms "internal" and "external" are defined with respect to the right and left sides respectively of the sectional figures of the assembly.

On the inner part of the body surface, two bearing tracks are formed so as to allow them to rotate on two rows of rolling bodies 4. In addition, a fixed outer ring 5 of a bearing is mounted on the hub 1 , said ring also comprising two bearing tracks arranged opposite those of the hub 1 so as to form a raceway for the rolling bodies 4. In known manner, the rolling bodies 4 of a row are maintained at equidistance and are guided in rotation through a cage. In the embodiments shown, the rolling bodies 4 are balls, but could be provided other geometry, including rollers of a conical bearing, and a number of rows of rolling bodies 4 different.

To allow the combination of the assembly on the chassis of the motor vehicle, the outer ring 5 comprises a radial flange 6 provided with orifices 7 forming fastening means by screwing the assembly on a rocket door. In addition, in the embodiments shown, fixing holes 8 of the brake caliper are also provided in the flange 6. As a variant not shown, it could be provided that the outer ring 5 has no flange, the combination from said ring to the rocket door being then feasible by fitting.

The running space formed between the outer ring 5 and the hub 1 is sealed by two seals 9, 10 respectively provided on the inner and outer side faces of said space.

The outer seal 9 comprises a frame 9a mounted in an annular recess of the outer ring 5, and an elastomeric lip 9b associated with the frame, for example by overmolding. The lip 9b comprises a free portion which bears against a bearing surface of the body surface. In the following description, this type attached will be called "first type" of seal.

The inner seal 10 comprises an outer armature 10a fitted into the outer ring 5 and an inner armature 10b fitted on the surface of the body, so as to form an annular space between said armatures. An elastomeric lip 10c is associated with the outer armature 10a, said lip comprising at least one free portion bearing against the inner armature 10b. In the rest of the description, this type will be called a "second type" of joint.

The assembly further comprises a tripod joint which is disposed in the bore of the hub 1 so as to transmit the engine torque to said hub. The assembly according to the invention has the advantage of not requiring a seal tripod of complex realization. The tripod joint shown comprises an inner ring 11 provided with a bore coaxial with the bore of the hub 1. The outer surface of the inner ring 11 is provided with convex bearing paths for rolling bodies 12 which are held by a cage 13 between said bearing paths and concave bearing paths provided on the periphery of the bore of the hub 1.

To improve the compactness of the assembly and reduce the steering angle of the wheel, it can be provided that the median transverse plane P1 of the tripod joint is disposed between the inner transverse plane P2 of the bearing and the median transverse plane P3 of said bearing. In the embodiment of FIG. 1, the median transverse plane P1 of the tripod joint is substantially coincident with the internal transverse plane P2 of the bearing.

The assembly further comprises a secondary transmission shaft 14 which is fixed to the tripod joint by fitting the outer end portion of said shaft into the bore of the inner ring 11 of said tripod joint. In particular, the axial retention of the secondary shaft 14 in the bore is achieved by means of a stop member formed of a ring 15 which is disposed between two annular grooves provided respectively opposite the bore of the inner ring 11 and on the outer surface of the shaft 14. In addition, the outer end portion of the shaft comprises an annular bearing surface 16 which comes into contact with the inner side face of the inner ring 11. In addition, to ensure the transmission of the rotational torque, one can provide axial grooves respectively on the bore of the inner ring 11 and on the outer surface of the outer end portion of the shaft 14.

The inner end portion of the secondary transmission shaft 14 is provided with a reversible coupling device with a motor transmission shaft 17. This embodiment, by integrating part of the transmission function, makes it possible to simplify the assembly of the transmission. together on the engine transmission shaft 17 by providing that the coupling is no longer made at the tripod joint, and without complicating the completion of said seal. Thus, the standard exchange of the rolling bearing is simplified. In the assembly shown, a bellows 18 is provided between the hub 1 and the inner end portion. This bellows 18, typically made of elastomeric material, protects the tripod joint pollutants. In addition, a lubricant of the tripod joint is contained in the bellows. In this embodiment, the presence of the reversible coupling device according to the invention makes it possible to overcome the lubrication constraints of the tripod joint during the coupling and uncoupling of the assembly with the motor transmission shaft 17.

In the embodiments described, the reversible coupling device comprises a clamping nut 19 which is provided around the inner end portion of the secondary transmission shaft 14.

In the embodiment shown in Figure 1, the inner end portion of the secondary shaft comprises a cylindrical end of diameter D1 which is provided to allow the arrangement of the motor transmission shaft 17 around said end. In particular, the outer end of the motor shaft comprises a blind bore 17a of diameter slightly greater than D1 so as to accommodate the end of the secondary shaft inside thereof (see Figure 3).

Moreover, to ensure the transmission of the rotational torque, axial splines 14a can be provided respectively on the bore and on the outer surface of the end. The inner end portion also includes a cylindrical portion adjacent the end, whose diameter D2 is substantially the same as the outside diameter of the bore 17a of the drive shaft 17.

The bellows 18 comprises a portion 18a forming a sheath for the adjacent portion, that is to say having a cylindrical housing of inner diameter substantially equal to D2. The sheath portion 18a extends axially around the end with a substantially constant inner diameter. In addition, the sheath portion 18a comprises an axial thread on which the nut 19 is moves axially by screwing so as to allow the realization of a tight contact between the portion 18a and the outer surface of the drive shaft 17.

In particular, during screwing, the nut 19 moves from one position around the adjacent portion in which the shafts 14, 17 can be joined, to a position where it is also arranged around the end, the contact tightening ensuring the coupling being made in this second position. In addition, due to the screwing and the nature of the material forming the bellows 18, a tight coupling is obtained between the two shafts 14, 17.

According to the embodiment shown in Figure 1, the nut 19 is formed of a folded sheet 19a comprising an axial annular portion provided with a thread, and an axi-radial fold.

According to the variant of Figure 4, the nut 19 is formed of a ring 19b whose bore is provided with a thread, and whose outer surface has a geometry for the realization of the clamping, including the nut is nut type full nut, solid hex nut or solid nut with grooves.

In addition, as shown in FIGS. 4a and 4b, axial notches 20 are provided on the inner surface of the sheath portion 18a, said notches cooperating with axial projections 21 provided on the outer surface of the adjacent portion so as to avoid the rotation of the bellows 18 during the tightening of the nut 19.

FIG. 5 represents a second embodiment of an assembly in which the reversible coupling device is identical to that of FIG. 4. In this embodiment, the bore of the hub 1 is plugged on the outer side by a bridge of material 30, for example from the foundry of the hub. The material bridge 30 mechanically reinforces the hub 1. This embodiment is made possible because of the presence of the reversible coupling device because it makes non-mandatory external access to the tripod joint. However, as shown in FIG. 1, it is possible to provide a plug removable 22 on the outer side of the hub so as to maintain external access to the tripod joint.

In the embodiments shown, an annular reinforcement 23 is provided between the bellows 18 and the hub 1 to seal between the inside and the outside of the bellows 18. In the embodiment of FIGS. armature 23 is not integrated in the bellows 18 but allows, by fitting and possibly clipping on a cylindrical surface of the outer surface of the body of the hub 1, to seal between the bellows 18 and said hub. In particular, the frame 23 comprises a radial flange 23a.

As described with reference to FIGS. 6a to 6e, this armature 23 can be used as a support for an angular encoder means 24 of the bearing. In fact, in wheel bearings for a motor vehicle, it has become necessary to code the angular position of the wheel relative to the chassis so as to deduce rolling parameters such as the speed of rotation of the wheel. The encoder means 24 may be of the magnetic or optical type, for example in the form of an annular body formed of a binder in which magnetic particles are magnetized so as to present a tangentially alternating succession of North and South poles.

According to FIGS. 6a and 6b, the armature 23 comprises, connected to the rim 23a, a substantially axial wall 23b on which is disposed, by overmolding, gluing or the like, the encoder means 24. In this embodiment, the reading of the signal coming from the encoder 24 is radially, and a sensor (not shown) is provided reading distance from the encoder 24 to detect this signal. On the other hand, in FIG. 6a the outer seal is of the first type 9 and the inner seal is of the second type 10, while in FIG. 6b the inner and outer seals are of the first type 9.

According to FIGS. 6c to 6e, the armature 23 further comprises, connected to the axial wall 23b, a substantially radial wall 23c on which the encoder means 24 is arranged for a facial reading of the signal. The seal in FIGS. 6c and 6d is produced with the same types of joint as on the Figures 6b and 6a. In Figure 6e, the axial portion 23b has been elongated with respect to Figure 6d so that the radial portion 23c is disposed near the inner seal. The seal used is then of the first type with a free portion of the lip which bears against the face of the radial portion 23c which is opposed to the encoder means 24.

FIG. 7 represents a third embodiment of an assembly which differs from the first one in that the bearing comprises two inner rings 25a, 25b which are fixed on the outer surface of the hub 1. In this embodiment, the hub 1 is therefore devoid of The inner rings 25a, 25b are held axially on the one hand by an outer annular abutment 26 on which the outer lateral face of a ring 25a abuts, and on the other hand by realization of a flange 27 after fitting of the inner rings 25a, 25b. To achieve this flange 27, one can for example use a method such as that described in FR-A1-2 827 202. The flange 27 is then substantially radial and bears on the inner side face of a ring 25b.

In this third embodiment, the median transverse plane P1 of the tripod joint is substantially coincident with the median transverse plane P3 of the bearing.

Furthermore, the armature 23 is associated with the bellows 18 so as to allow its association on the hub 1 by fitting, said armature comprising a radial flange 23a. In relation to FIGS. 8a to 8e, arrangements of the encoder means 24 are described on such a frame 23.

According to FIGS. 8a and 8b, the armature 23 comprises, connected to the flange 23a, a substantially axial wall 23b on which the encoder means 24 is arranged for a radial reading. On the other hand, in FIG. 8a the outer seal is of the first type 9 and the inner seal is of the second type 10, whereas in FIG. 8b the inner and outer seals are of the first type 9. According to Figures 8c to 8e, the armature 23 further comprises, connected to the axial wall 23b, a substantially radial wall 23c on which is disposed the encoder means 24 for a facial reading of the signal. The seal in FIGS. 8c and 8d-8e is made with the same types of seal as in FIGS. 8b and 8a respectively. Furthermore, in FIG. 8e, the flange 23a comprises a curved fold 23e to surround the flange 27. In addition, the axial wall 23b covers the space between the flange 27 and the inner ring 25b, which contributes to limiting the corrosion phenomenon at this level. It is also possible that the armature 23 is overmolded by an elastomeric material to improve its sealing function. Alternatively not shown, it is also possible that the encoder means 24 is disposed on the inner face of the wall 23c.

As described above, the instrumentation of the armature 23 of a bellows 18 on a hub 1 has advantages that can be used by those skilled in the art independently of the reversible coupling device. Therefore, the present description also relates to a rolling bearing assembly for a motor vehicle drive wheel, said assembly comprising a rotating hub 1 on which the wheel is intended to be mounted, a fixed outer ring 5 of a bearing which is mounted on the hub 1 via rolling bodies 4 so as to allow the combination of said assembly to the chassis of the vehicle, said hub comprising a bore in which a tripod joint is disposed, wherein a frame 23 carrying an angular encoder means 24 as described above is provided to associate a bellows 18 between the hub 1 and a transmission shaft associated with the tripod joint.

Claims

Rolling bearing assembly for a drive wheel of a motor vehicle, said assembly comprising a rotating hub (1) on which the wheel is to be mounted, a fixed outer ring (5) of a bearing which is mounted on the hub (1) by means of rolling bodies (4) so as to allow said assembly to be associated with the vehicle chassis, said hub comprising a bore in which a tripod joint is arranged, said assembly being characterized in that it comprises in addition a secondary transmission shaft (14) which is fixed to the tripod joint, the inner end portion of said secondary transmission shaft being provided with a reversible coupling device with a motor transmission shaft (17).

2. An assembly according to claim 1, characterized in that the tripod joint comprises an inner ring (11) provided with a bore coaxial with the bore of the hub (1), the outer end portion of the secondary transmission shaft ( 14) being fixed in the bore of said inner ring.

3. An assembly according to claim 2, characterized in that the inner ring (11) is provided with raceways for rolling bodies.

(12) which are held by a cage (13) between said raceways and raceways provided on the periphery of the bore of the hub (1).

4. The assembly of claim 2 or 3, characterized in that the bore of the inner ring (11) comprises an annular groove which is provided opposite an annular groove provided on the outer surface of the secondary transmission shaft a stop member (15) being disposed in said grooves for axially holding said shaft in the bore.

5. An assembly according to any one of claims 1 to 4, characterized in that the bearing comprises at least one inner ring (25a, 25b) which is fixed on the outer surface of the hub (1).

6. An assembly according to claim 5, characterized in that the inner ring (25a, 25b) is fixed by fitting and producing a substantially radial flange (27) bearing on an inner side face of the inner ring (25b). .

7. An assembly according to any one of claims 1 to 6, characterized in that the outer ring (5) comprises a radial flange (6) provided with fixing means (7) of said assembly on a rocket door.

8. The assembly of claim 7, characterized in that the flange (6) further comprises fixing means (8) of a brake caliper.

9. An assembly according to any one of claims 1 to 8, characterized in that the hub (1) comprises a radial flange (2) provided with fixing means (3) of the wheel.

10. An assembly according to any one of claims 1 to 9, characterized in that the bore of the hub (1) is plugged on the outer side by a material bridge (30).

11. An assembly according to any one of claims 1 to 10, characterized in that the median transverse plane (P1) of the tripod joint is disposed between the inner transverse plane (P2) of the bearing and the median transverse plane (P3) of said bearing. .

12. An assembly according to any one of claims 1 to 11, characterized in that a bellows (18) is provided between the hub (1) and the inner end portion, said bellows containing a lubricant for the tripod joint.

An assembly according to any one of claims 1 to 12, characterized in that the reversible coupling device comprises a clamping nut (19) which is provided around the inner end portion of the secondary drive shaft (14). ).

14. The assembly of claim 12 and 13, characterized in that the inner end portion comprises an end of diameter D1 which is provided to allow the arrangement of the motor transmission shaft (17) around said end, and an adjacent portion of diameter D2 greater than D1 which is intended to be substantially the same as the outer diameter of the motor drive shaft (17), the bellows (18) comprising a sleeve portion (18a) for the adjacent portion and extending around the end, said portion comprising a thread on which the nut (19) is intended to allow the realization of a tight contact between the bellows (18) and the outer surface of the shaft (17).

15. The assembly of claim 14, characterized in that notches (20) are provided on the inner surface of the portion (18a) forming a sheath, said notches cooperating with projections (21) provided on the outer surface of the adjacent portion. , so as to avoid rotation of the bellows (18) when tightening the nut (19).

16. The assembly of claim 14 or 15, characterized in that the outer surface of the end comprises axial grooves (14a).

17. An assembly according to any one of claims 13 to 16, characterized in that the nut (19) is formed of a folded sheet (19a).

18. Assembly according to any one of claims 13 to 16, characterized in that the nut (19) is formed of a ring (19b) whose outer surface has a geometry allowing the realization of clamping.

19. An assembly according to any one of claims 12 to 18, characterized in that an annular reinforcement (23) is provided between the bellows (18) and the hub (1).

20. The assembly of claim 19, characterized in that the armature (23) comprises a substantially axial wall (23b) on which is disposed a radial encoder means (24) radial reading.

21. An assembly according to claim 19, characterized in that the armature (23) comprises a substantially radial wall (23c) on which is disposed a facet angle encoder means (24).

22. An assembly according to any one of claims 19 to 21, characterized in that the armature (23) is associated with the bellows (18) so as to allow its association on the hub (1) by fitting.