Sealed clutch thrust bearing device and transmission system including such a device

Abstract

The invention relates to a clutch thrust bearing device (1) comprising a rolling bearing (4), an axially movable piston (6) having a radial plate (11a), and an elastic biasing member (7). The device (1) further comprises a sleeve (30) made of elastic material and mounted together with a fixed ring (16), the sleeve (30) comprising at least one sealing lip (36) in sliding contact with a rotatable ring (17).

Description

Technical Field

[0001] The present invention relates to a clutch thrust bearing arrangement comprising a bearing and a driveline system comprising such an arrangement, the driveline system being arranged in an all-wheel drive driveline system of a motor vehicle. Background Art

[0002] An all-wheel drive drivetrain for a motor vehicle typically includes a primary front drive shaft coupled to a secondary or rear drive shaft.

[0003] When only two wheels of a four-wheeled vehicle are operated as drive wheels, the rear drive system comprising the rear drive shaft and the rear wheels can be disconnected from the front drive system comprising the front drive shaft and the front wheels. In addition, it may be desirable to disconnect only one of the rear wheels or both rear wheels depending on the operating mode of the motor vehicle.

[0004] To this end, it is known to provide a rear drive module in the rear drive system, said rear drive module including a clutch thrust device to distribute torque between the front and rear axles and between the two wheels. The clutch thrust device can also disconnect the rear drive system, so that the wheels are not coupled to the driveline. It is also known that the rear drive module includes two clutches, each clutch being able to disconnect a rear wheel from the driveline.

[0005] Such a rear drive module provides the motor vehicle with off-road capability and high performance on the road, in particular with high stability, high dynamics and low fuel consumption.

[0006] Advantageously, the clutch thrust device is of the known multi-plate type and comprises an axially movable piston arranged in a cavity between the clutch bearing and the housing, the piston cavity being connected to a hydraulic fluid source which can variably provide pressurized fluid in the cavity to move the piston axially. The clutch thrust device also comprises an elastic biasing member which applies an axial preload to the clutch bearing. The clutch bearing can be moved axially by the movement of the piston and then actuates the coupling member of the coupling plate. It is known to use such a clutch bearing which has a plurality of rolling elements (e.g. needle rollers or balls) which are arranged in a raceway chamber defined between two rings which rotate relative to each other.

[0007] Rolling elements and races are affected by contamination, which increases the friction torque in the clutch bearings, further increasing vehicle fuel consumption, deteriorating these parts and reducing the service life of the clutch bearings. Therefore, it is desirable to further improve the performance of such rear drive modules, in particular by protecting the raceway chamber from particles and dust. Summary of the Invention

[0008] The object of the present invention is to overcome these drawbacks by proposing a sealed clutch thrust bearing, in particular, the sealed thrust bearing is used in a rear drive module of a transmission system of a motor vehicle, and is capable of transmitting axial force from an axially movable piston to an elastic biasing member, reducing friction torque, extending service life, and simplifying the manufacturing process and reducing the cost of the manufacturing process.

[0009] To this end, the present invention relates to a clutch thrust bearing arrangement comprising a rolling bearing, an axially movable piston, and an elastic biasing member.

[0010] The rolling bearing has a fixed ring, a rotatable ring, and a plurality of rolling elements located in a raceway chamber defined between the fixed ring and the rotatable ring.

[0011] An axially movable piston is disposed between the housing and the rolling bearing. The axially movable piston includes a radial plate that bears against an axial contact surface of a retaining ring. The piston includes a housing sealing member formed of an elastomeric material to define a sealed piston cavity with the housing. The piston cavity is connected to a hydraulic fluid source that can variably provide pressurized fluid in the cavity to move the piston axially.

[0012] The resilient biasing member applies an axial preload ( / preload) on the axial contact surface of the rotatable ring, and the rolling bearing is able to move axially by piston movement, and then compresses the resilient biasing member, which actuates the connecting member of the coupling plate.

[0013] According to the invention, the device also comprises a sleeve made of elastic material and mounted together with the fixed ring, the sleeve comprising at least one sealing lip in sliding contact with the rotatable ring.

[0014] According to further advantageous but non-limiting aspects of the invention, such a ball bearing may include one or more of the following features:

[0015] - The rolling elements are balls. The rolling elements are balls located in raceway chambers defined between the rings.

[0016] - The fixed ring is the inner ring and the rotatable ring is the outer ring.

[0017] - The fixed ring is the outer ring and the rotatable ring is the inner ring.

[0018] The ball bearing further comprises an annular cage comprising a plurality of cavities for receiving each ball.

[0019] - The inner ring and the outer ring are made of tempered steel.

[0020] - The radial plates are made of steel.

[0021] The housing sealing element comprises an inner lip and an outer lip in sliding contact with the wall of the piston chamber.

[0022] - The housing sealing component is made of polymer or synthetic material.

[0023] - The housing sealing component is over-molded onto the radial plate.

[0024] - The elastic biasing member is a wave spring.

[0025] - The sleeve is made of a synthetic or polymer material.

[0026] The retaining ring comprises a toroidal portion provided with a toroidal surface forming a raceway for the balls, and a radial portion extending radially from the toroidal portion and provided with an axial contact surface abutting against the axially movable piston.

[0027] The sleeve is mounted on the surface of the annular portion radially facing away from the raceway.

[0028] - the rotatable ring comprises an annular portion provided with an annular surface forming a raceway for the balls, and a radial portion extending radially from the annular portion and provided with an axial contact surface abutting the elastic biasing member.

[0029] The sealing lip of the sleeve is in sliding contact with a surface of the radial portion of the rotatable ring axially facing away from the axial contact surface.

[0030] The sleeve comprises an axial annular body from which the sealing lip extends axially towards the rotatable ring.

[0031] The sleeve comprises a first supporting portion directed towards the fixing ring and cooperating with the annular portion of the fixing ring.

[0032] - said first supporting portion is annular and has a shape substantially corresponding to the annular portion of said fixing ring.

[0033] The first supporting portion comprises a first series of circumferentially spaced ribs cooperating with the free edge of the annular portion to block the retaining ring in a first axial direction.

[0034] The first supporting portion comprises a second series of ribs spaced apart in the circumferential direction, said ribs cooperating with the annular surface opposite the raceway of the annular portion to block the retaining ring in a second axial direction.

[0035] The ribs of the first series and the ribs of the second series are arranged at the same angular position.

[0036] The ribs of the first series and the ribs of the second series are arranged alternately in the circumferential direction.

[0037] The axially movable piston comprises an axial portion extending axially from the periphery of the radial plate towards the rotatable ring.

[0038] - said sleeve comprises a second supporting portion directed towards said axial portion of the piston.

[0039] - The second supporting portion is annular.

[0040] - the second supporting portion comprises a plurality of ribs spaced apart in the circumferential direction.

[0041] The axial portion comprises at least one protruding portion which protrudes radially from the axial portion towards the sleeve and which cooperates with the second supporting portion to block the sleeve in an axial direction.

[0042] - The protrusion is annular.

[0043] - The protruding portion is made of elastic material.

[0044] - The protruding portion is part of a sealing gasket of elastic material covering the surface of the axial portion.

[0045] The lip of the housing sealing element is formed integrally with the sealing gasket and the projection.

[0046] The invention also relates to a transmission system for a motor vehicle, comprising a clutch thrust bearing arrangement according to the invention for selectively connecting or disconnecting at least one wheel from the transmission system.

[0047] Advantageously, the transmission system includes a front drive system and a rear drive system, the front drive system includes a front drive shaft and front wheels, the rear drive system includes a rear drive shaft, a rear drive module and rear wheels, the rear drive module is arranged in series with the clutch thrust bearing device according to the present invention, and each clutch thrust bearing device can selectively connect or disconnect with one of the rear wheels. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] The invention will now be explained with reference to the accompanying drawings which are provided as illustrative examples and not for limiting purposes of the invention. In the drawings:

[0049] - Figure 1 is an axial section AA of a clutch thrust bearing device including a ball bearing according to a first embodiment of the present invention;

[0050] - Figure 2 yes Figure 1 Axial cross section BB of the clutch thrust bearing assembly;

[0051] - Figure 3 yes Figure 1 and Figure 2 a radial cross-section of a clutch thrust bearing assembly; and

[0052] - Figure 4 is a perspective view of a sleeve according to a second embodiment of the present invention. DETAILED DESCRIPTION

[0053] like Figure 1 As shown, the clutch thrust bearing arrangement 1 is advantageously integrated in a driveline system (not shown) of a motor vehicle. The clutch thrust bearing arrangement 1 is substantially annular and centred on a central axis.

[0054] The clutch thrust bearing device 1 includes a fixed housing 3, a rolling bearing (here a ball bearing 4) and an elastic biasing member 7 (for example, a wave spring) shown in a dotted line. The fixed housing 3 and the ball bearing 4 define a cavity 5 in which an axially movable piston 6 is arranged.

[0055] The housing 3 is stationary and advantageously is part of a rear drive module provided in the transmission system. The housing comprises an annular cavity 5 centered on a central axis. The cavity 5 is defined between two lateral ( / transverse) walls 8, 9 and a bottom surface 10, and is open axially towards the ball bearing 4.

[0056] The piston 6 is annular, centered on a central axis, and is disposed in the cavity 5 of the housing 3. The piston 6 comprises a substantially radial plate 11 a extending in the radial direction between the two lateral walls 8, 9 of the cavity 5. The piston 6 is provided with an inner axial portion 11 b extending axially from the inner periphery of the radial plate 11 a toward the ball bearing 4, and an outer axial portion 11 c extending axially from the outer periphery of the radial plate 11 a toward the ball bearing 4.

[0057] Advantageously, the piston 6 further comprises an inner sealing member 12 made of an elastic material and disposed within the inner bore of the radial plate 11a. The sealing member is provided with a sealing lip that is in sliding contact with the lateral wall 8 of the chamber 5. The piston further comprises an outer sealing member 13 made of an elastic material and disposed outside the radial plate 11a. The sealing member is provided with a sealing lip that is in sliding contact with the transverse wall 9 of the chamber 5. Advantageously, the inner sealing member 12 is attached to the inner axial portion 11b, and the outer sealing member 13 is attached to the outer axial portion 11c. Advantageously, the sealing members 12 and 13 are made of a polymer or synthetic material. Advantageously, the sealing members 12 and 13 are overmolded onto the axial portions 11b and 11c, respectively.

[0058] The piston 6, the lateral walls 8 and 9, and the bottom surface 10 define a sealed chamber 14. At least one passage 15 is provided through the housing 3 to connect the sealed chamber 14 to a hydraulic fluid source (not shown), which can variably provide pressurized fluid in the sealed chamber 14 to move the piston 6 in the axial direction. The lateral walls 8, 9 of the chamber 5 allow lateral guidance of the piston 6.

[0059] In the present embodiment, the substantially radial plate 11a of the piston 6 has a shape adapted to the ball bearing 4. Alternatively, the substantially radial plate 11a may have any other suitable shape.

[0060] The ball bearing 4 is annular and centered on the central axis. The ball bearing 4 is at least partially arranged in a cavity 5 of the housing 3, with the piston 6 axially interposed between a bottom surface 10 of the cavity 5 and the ball bearing 4.

[0061] The ball bearing 4 comprises a stationary inner ring 16, a rotatable outer ring 17 and a series of balls 18 located in a raceway chamber 19 defined between the rings 16, 17. Alternatively, the bearing 4 may comprise any other suitable type of rolling elements, such as rollers or needle rollers.

[0062] The fixed inner ring 16 includes an annular portion 20 having an outer toroidal surface 21 that forms an inner raceway for the balls 18, and a radial portion 22 that extends radially outward from the annular portion 20. The radial portion 22 has an axial contact surface 23 that bears against the radial plate 11a of the axially movable piston 6. The ball bearing 4 is set in axial motion by transmitting the movement of the piston 6 to the axial contact surface 23 of the fixed inner ring 16.

[0063] The rotatable outer ring 17 comprises an annular portion 24 having an inner annular surface 25 forming an outer raceway for the balls 18 .

[0064] Advantageously, the rotatable outer ring 17 further comprises a radial portion 26 extending radially outwards from the inner side of the annular portion 24. The radial portion 26 has an axial contact surface 27 abutting the elastic biasing member 7 in the axial direction.

[0065] As an alternative not shown, the rotatable ring cooperating with the elastic biasing member 7 may be the inner ring, while the fixed ring cooperating with the axially movable piston 6 may be the outer ring.

[0066] Advantageously, the ball bearing 4 further comprises an annular cage 28 comprising a plurality of cavities for receiving each ball 18. The balls 18 are then equally spaced and retained in the circumferential direction.

[0067] According to the invention, the device 1 also comprises a sleeve 30 made of elastic material and mounted together with the fixed inner ring 16 .

[0068] The sleeve 30 comprises an annular body 31 arranged in the hole defined by the annular portion 20 of the fixed inner ring 16. The sleeve 30 also comprises a first support portion 32 directed towards the fixed inner ring 16 and cooperating with the annular portion 20 of said ring 16. The first support portion 32 generally has a shape corresponding to the inner surface of said annular portion 20. Figure 3 As shown, the first support portion 32 according to the first embodiment of the present invention includes a series of ribs spaced apart in the circumferential direction, which cooperate with the inner surface of the annular portion 20 to block the retaining ring 16 in the first axial direction toward the piston 6. Alternatively, the first support portion 32 is annular.

[0069] The annular body 31 includes a shoulder 33 that points toward the bearing 4 and forms a stop for the free edge of the annular portion 20, blocking the retaining ring 16 in a second axial direction opposite to the first axial direction. Thanks to the shoulder 33 on one axial side and the rib on the second axial side, the sleeve 30 is then attached to the inner ring 16. The sleeve 30 can be installed in the annular portion 20 by deformation of the elastic material.

[0070] The sleeve 30 further comprises a second support portion 34 directed towards the inner axial portion 11b of the piston 6. The second support portion 34 is mounted on the outer surface of the inner axial portion 11b. The second support portion 34 has a shape substantially corresponding to that of the inner axial portion 11b. Figure 3 As shown, the second support portion 34 according to the first embodiment of the present invention comprises a series of ribs spaced apart in the circumferential direction, said ribs cooperating with the inner surface of the inner axial portion 11b. The second support portion 34 is blocked in the first axial direction by the radial plate 11 of the piston 6. Alternatively, the second support portion 34 is annular.

[0071] like Figure 1and Figure 2 As shown, the free end of the inner axial portion 11b of the piston 6 is provided with a radial projection ( / protrusion) 35. The radial projection 35 can be annular or include a plurality of circumferentially spaced portions. Said portion 35 cooperates with the second support portion 34 of the sleeve 34 to block the sleeve 30 relative to the piston 6 in a second axial direction opposite to the first axial direction. Advantageously, the radial projection 35 is made of an elastic material and deforms when the piston 6 and the sleeve 30 are mounted together. Advantageously, the radial projection 35 is made of a synthetic material or a polymer material and is advantageously formed ( / molded) onto the inner axial portion 11b. Advantageously, the radial projection 35 is formed integrally with the inner sealing lip 12.

[0072] The sleeve 30 is then mounted between and attached to the stationary inner ring 16 and the piston 6 .

[0073] According to another embodiment of the invention, the sleeve 30 further comprises at least one annular sealing lip 36 in sliding contact with the radial portion 26 of the rotatable outer ring 17. The sealing lip 36 extends axially from the axial body 31 towards the rotatable outer ring 17. As an alternative, not shown, the sleeve 30 may comprise two or more sealing lips in sliding contact with the rotatable outer ring 17 or forming a labyrinth seal.

[0074] Figure 4 Another embodiment of the present invention is shown in FIG. A sleeve 30 includes an annular body 31 provided with a first series of ribs 37 spaced apart in the circumferential direction. These ribs 37 cooperate with the free edge of the annular portion 20 to block the fixed inner ring 16 in a first axial direction. The sleeve 30 also includes a second series of ribs 38 spaced apart in the circumferential direction. These ribs 38 cooperate with the annular surface opposite the raceway 21 of the annular portion 20 to block the fixed inner ring 16 in a second axial direction. The first series of ribs 37 and the second series of ribs 38 are arranged alternately in the circumferential direction. According to an alternative embodiment, the first and second series of ribs are arranged at the same angular position.

[0075] exist Figure 4 In the embodiment shown in FIG, the sleeve 30 comprises a second support portion 39 directed towards the inner axial portion of the piston and dedicated to cooperating with said inner axial portion. The second support portion 39 is annular.

[0076] Representative, non-limiting examples of the present invention have been described in detail above with reference to the accompanying drawings. This detailed description is intended only to teach those skilled in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the present invention. Furthermore, each of the additional features and teachings disclosed above can be used alone or in combination with other features and teachings to provide improved ball bearings.

[0077] Furthermore, various features of the above representative examples and of each independent and dependent claim may be combined in ways not specifically and expressly recited to provide other useful embodiments of the present teachings.

Claims

1. A clutch thrust bearing device (1), comprising: - a rolling bearing (4) having a fixed ring (16), a rotatable ring (17) and a plurality of rolling elements (18) located in a raceway chamber (19) defined between the fixed ring (16) and the rotatable ring (17); - an axially movable piston (6) arranged between the housing (3) and the rolling bearing (4), the axially movable piston (6) having a radial plate (11a) bearing against an axial contact surface (23) of the fixing ring (16); - a housing sealing member made of an elastic material, sealing the piston relative to the housing and forming a piston chamber, the piston chamber (14) being connectable to a hydraulic fluid source (15) for variably supplying pressurized fluid to the piston chamber (14) to move the piston (6) in the axial direction; - an elastic biasing member (7) exerting an axial preload on the axial contact surface (27) of the rotatable ring (17), said rolling bearing (4) being moved axially by the piston movement and then compressing said elastic biasing member (7); and a sleeve made of elastic material, mounted on the fixed ring (16), the sleeve (30) comprising at least one sealing lip (36) in sliding contact with the rotatable ring (17); The housing sealing component (12) includes a radial protrusion (35), and the radial protrusion (35) is configured to limit the axial movement of the sleeve (30) relative to the piston (6).

2. The device according to claim 1, characterized in that The rolling element (18) is a ball, the fixed ring (16) includes an annular portion (20) and a radial portion (22), the annular portion (20) of the fixed ring (16) is provided with an annular surface (21) forming a raceway for the ball (18), the radial portion (22) of the fixed ring (16) radially extends from the annular portion (20) of the fixed ring (16) and is provided with an axial contact surface (23) abutting against the axially movable piston (6), and the sleeve (30) is mounted on the surface of the annular portion (20) of the fixed ring (16) that is radially opposite to the annular surface (21) of the fixed ring (16).

3. The device according to claim 1 or 2, characterized in that The rolling element (18) is a ball, wherein the rotatable ring (17) includes an annular portion (24) and a radial portion (26), the annular portion (24) of the rotatable ring (17) is provided with an annular surface (25) forming a raceway for the ball (18), the radial portion (26) of the rotatable ring (17) radially extends from the annular portion (24) of the rotatable ring (17) and is provided with an axial contact surface (27) abutting the elastic biasing member (7), and the sealing lip (36) of the sleeve (30) is in sliding contact with a surface of the radial portion (26) of the rotatable ring (17) that is axially opposite to the axial contact surface (27) of the rotatable ring (17).

4. The device according to claim 1, characterized in that The sleeve (30) comprises an axial annular body (31) from which the sealing lip (36) extends axially towards the rotatable ring (17).

5. The device according to claim 4, characterized in that The sleeve comprises a first supporting portion (32) which points towards the fixing ring (16) and cooperates with the annular portion (20) of the fixing ring (16).

6. The device according to claim 4 or 5, characterized in that The axially movable piston (6) includes an axial portion (11b) extending axially from the outer periphery of the radial plate (11a) toward the rotatable ring (17), and the sleeve (30) includes a second support portion (34) pointing toward the axial portion (11b) of the piston (6).

7. The device according to claim 6, characterized in that The axial portion (11b) includes at least one radial protrusion (35) that radially protrudes from the axial portion (11b) toward the sleeve (30) and cooperates with the second supporting portion (34) to block the sleeve (30) in one axial direction.

8. The device according to claim 7, characterized in that The radial protrusion (35) is made of elastic material.

9. A transmission system for a motor vehicle comprising a clutch thrust bearing arrangement (1) according to any one of the preceding claims for selectively connecting or disconnecting at least one wheel to the transmission system.

10. The transmission system according to claim 9, wherein the transmission system includes a front drive system and a rear drive system, the front drive system includes a front drive shaft and front wheels, the rear drive system includes a rear drive shaft, a rear drive module and rear wheels, the rear drive module is arranged in series with the clutch thrust bearing device (1) according to any one of the preceding claims, and each clutch thrust bearing device can be selectively connected or disconnected with one of the rear wheels.

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