HYDROKINETIC TORQUE COUPLING DEVICE FOR A MOTOR VEHICLE

Abstract

The invention relates to a hydrokinetic. torque coupling device, comprising an impeller wheel (2) able to hydrokinetically drive a turbine wheel (3) into rotation, with the turbine wheel (3) being able to be axially moved between an engaged position and a disengaged position, characterized in that the radially external periphery of the turbine wheel (3) comprises a seal (18) able to come to rest onto a matching sealing surface (22) positioned radially outside the turbine wheel (3), onto the impeller wheel (2) or onto a part (5) rotationally coupled to the impeller wheel (2) in the disengaged position.

Claims

1. A hydrokinetic torque coupling device for a motor vehicle, comprising an impeller wheel (2) intended to be coupled to a crankshaft and able to hydrokinetically drive a turbine wheel (3) into rotation, with the turbine wheel (3) being able to be axially moved between an engaged position in which the turbine wheel (3) and the impeller wheel (2) are rotationally coupled together, and a disengaged position, in which the turbine wheel (3) and the impeller wheel (2) are rotationally uncoupled, wherein the radially external periphery of the turbine wheel (3) comprises a seal (18) able to come to rest onto a matching sealing surface (22) positioned radially outside the turbine wheel (3), onto the impeller wheel (2) or onto a part (5) rotationally coupled to the impeller wheel (2) in the disengaged position.

2. A hydrokinetic torque coupling device (1) according to claim 1, wherein the seal (18) is able to be moved away from said sealing surface (22) in the disengaged position.

3. A hydrokinetic torque coupling device (1) according to claim 1, wherein the turbine wheel (3) comprises friction means (26, 27) able to cooperate with matching friction means (9) on the impeller wheel (2) or a part (5) connected to said impeller wheel (2), with the friction means (26, 27) of the turbine wheel (3) being positioned in a zone away from the seal (18).

4. A hydrokinetic torque coupling device (1) according to claim 1, wherein ale impeller wheel (2) or said part (5) connected to said impeller wheel (2) comprises a cylindrical surface (22) and an annular groove (20) arranged in said cylindrical surface (22), with the seal (18) of the turbine wheel (3) being annular and being able to come to rest onto said cylindrical surface (22) in the engaged position, with the seal (18) being positioned axially opposite the groove (20) in the disengaged position.

5. A hydrokinetic torque coupling device (1) according to claim 1, wherein the joint (18) is a lip seal (19).

6. A hydrokinetic torque coupling device (1) according to claim 1, wherein the turbine wheel (3) and/or the seal (18) comprise(s) leakage means (23) able to enable a fluid. flow through said turbine wheel (3) and/or said seal (18).

7. A hydrokinetic torque coupling device (1) according to claim 1, wherein it comprises a bracing member (24) axially extending between the turbine wheel (3) and a cover (5) rotationally coupled to the impeller wheel (2), with the bracing member (24) being able to limit the axial motion of the turbine wheel (3) towards the cover (5), opposite the turbine wheel (3).

8. A hydrokinetic torque coupling device (1) according to claim 7, wherein the bracing member (24) is attached to the turbine wheel (3) or to the cover (5), respectively, to a so-called attachment end, with the turbine wheel (3) or the cover (5), respectively being adapted to rest on another so-called rest end of the bracing member (24).

9. A hydrokinetic torque coupling device (1) according to claim 7, wherein the bracing member (24) is provided with at least one friction lining (27) adapted to come to rest onto a matching friction surface (9) of the cover (5), or the turbine wheel (3) respectively, in the engaged position, so as to provide the rotational coupling of the turbine wheel (3) and the cover (5).

10. A hydrokinetic torque coupling device (1) according to claim 1, wherein it comprises damping means (28) mounted between the turbine wheel (3) and a hub (11) intended to be coupled with a transmission input shaft.

11. A hydrokinetic torque coupling device (1) according to claim 10, wherein the damping means (28) comprise an annular wheel disc (12) connected to the hub (11) and a least one guiding washer (29, 30) connected to the turbine wheel (3), with at least a first elastic member (31) acting on the circumference being mounted between the annular wheel disc (12) and the guiding washer (29, 30), with the first elastic member (31) being adapted to oppose the rotation of the annular wheel disc (12) relative to the guiding washer (29, 30).

12. A hydrokinetic torque coupling device (1) according to claim 11, wherein the damping means (28) comprise at least one second elastic member (32) mounted between the guiding washer (29, 30) and the turbine wheel (3). with the second elastic member (32) being adapted to oppose the rotation of the turbine wheel (3) relative to the guiding washer (29, 30).

13. A hydrokinetic torque coupling device (1) according to claim 2, wherein the turbine wheel (3) comprises friction means (26, 27) able to cooperate with matching friction means (9) on the impeller wheel (2) or a part (5) connected to said impeller wheel (2), with the friction means (26, 27) of the turbine wheel (3) being positioned in a zone away from the seal (18).

14. A hydrokinetic torque coupling device (1) according to claim 2, wherein the impeller wheel (2) or said part (5) connected to said impeller wheel (2) comprises a cylindrical surface (22) and an annular groove (20) arranged in said cylindrical surface (22), with the seal (18) of the turbine wheel (3) being annular and being able to come to rest onto said cylindrical surface (22) in the engaged position, with the seal (18) being positioned axially opposite the groove (20) in the disengaged position.

15. A hydrokinetic torque coupling device (1) according to claim 3, wherein the impeller wheel (2) or said part (5) connected to said impeller wheel (2) comprises a cylindrical surface (22) and an annular groove (20) arranged in said cylindrical surface (22), with the seal (18) of the turbine wheel (3) being annular and being able to come to rest onto said cylindrical surface (22) in the engaged position, with the seal (18) being positioned axially opposite the groove (20) in the disengaged position.

16. A hydrokinetic torque coupling device (1) according to claim 2, wherein the joint (18) is a lip seal (19).

17. A hydrokinetic torque coupling device (1) according to claim 3, wherein the joint (18) is a lip seal (19).

18. A hydrokinetic torque coupling device (1) according to claim 4, wherein the joint (18) is a lip seal (19).

19. A hydrokinetic torque coupling device (1) according to claim 2, wherein the turbine wheel (3) and/or the seal (18) comprise(s) leakage means (23) able to enable a fluid flow through said turbine wheel (3) and/or said seal (18).

20. A hydrokinetic torque coupling device (1) according to claim 3 wherein the turbine wheel (3) and/or the seal (18) comprise(s) leakage means (23) able to enable a fluid flow through said turbine wheel (3) and/or said seal (18).

21. A hydrokinetic torque coupling device (1) according to claim 4, wherein the turbine wheel (3) and/or the seal (18) comprise(s) leakage means (23) able to enable a fluid flow through said turbine wheel (3) and/or said seal (18).

22. A hydrokinetic torque coupling device (1) according to claim 5, wherein the turbine wheel (3) and/or the seal (18) comprise(s) leakage means (23) able to enable a fluid flow through said turbine wheel (3) and/or said seal (18).

Description

[0049] The invention will be better understood, and other details, characteristics and advantages of the invention will appear upon reading the following description given by way of a non restrictive example while referring to the appended drawings wherein:

[0050] FIG. 1 is a half-sectional view along an axial plane, of a torque converter according to a first embodiment of the invention, in the disengaged position,

[0051] FIG. 2 is a detailed view of FIG. 1,

[0052] FIG. 3 is a view corresponding to FIG. 1, in the engaged position of he torque converter,

[0053] FIG. 4 is a detailed view of FIG. 3,

[0054] FIG. 5 is a view corresponding to FIG. 2, illustrating an alternative embodiment of the invention,

[0055] FIG. 6 is a schematic view illustrating a second embodiment of the invention,

[0056] FIG. 7 is a view corresponding to FIG. 6, illustrating a third embodiment of the invention,

[0057] FIG. 8 is a view corresponding to FIG. 6, illustrating a fourth embodiment of the invention.

[0058] A hydrokinetic torque coupling device according to a first embodiment of the invention is shown in FIGS. 1 to 4. The hydrokinetic torque coupling device is more particularly a hydrokinetic torque converter.

[0059] Such device makes it possible to transmit a torque from the output shaft of an internal combustion engine in a motor vehicle, such as for instance a crankshaft, to a transmission input shaft. The axis of the torque converter bears reference X.

[0060] In the following, the words “axial” and “radial” are defined relative to the X axis.

[0061] The torque converter 1 comprises an impeller bladed wheel 2, able to hydrokinetically drive a turbine bladed wheel 3 through a reactor 4.

[0062] The impeller wheel 2 is attached to a cover 5 by welding and defines with said cover 5 an internal volume 6 accommodating the impeller wheel 2, the turbine wheel 3 and the reactor 4. The impeller wheel comprises a cylindrical part 7 on the radially external periphery thereof, attached to a cylindrical part 8 of the cover 5, with the front end of said cylindrical part 8 being extended by a radial part 9 radially extending inwards. The radial part 9 comprises attaching means 10 making it possible to rotationally couple said cover 5 to the crankshaft.

[0063] The torque converter 1 further comprises a central hub 11, the radially internal periphery of which is ribbed, having an X axis and being accommodated in the internal volume 6. The central hub 11 comprises an annular rim 12 which radially extends outwards and a front end 13, facing the turbine wheel 3. A pad 14 adapted to limit friction and made of a synthetic material for instance, is inserted between the front end 13 of the hub 11 and the radial part 9 of the cover 5.

[0064] The turbine wheel 3 comprises a cylindrical rim 15 on the radially internal periphery thereof, mounted about a cylindrical part 16 formed at the back end of the hub 11. Said cylindrical part 16 comprises an O-ring 17 mounted in a groove of the hub 11. The turbine wheel 3 is adapted to axially move relative to said cylindrical part 16 of the hub 11.

[0065] An annular seal 18, such as an elastomeric lip seal, for instance is mounted on the radially external periphery of the turbine wheel 3. As can be best seen in FIG. 2, the lip 19 of said seal 18 is able to come to rest onto the radially internal cylindrical surface 22 of the cylindrical part 7 of the impeller wheel 2, or opposite the annular groove 20 arranged in said cylindrical surface 22, depending on the axial position of the turbine wheel 3.

[0066] The seal 18 is for example glued to the radially external periphery of the turbine wheel 3.

[0067] According to an alternative embodiment illustrated in FIG. 5, the seal 18 may be overmolded onto the turbine wheel 3.

[0068] The lip 19 may be tilted rearwards and radially outwards. The front end of the groove 20 may also comprise a surface 21 inclined in the same direction as the lip 19, so as to gradually follow the deformation of the lip 19 when the seal 18 axially moves from the groove 20 towards the cylindrical surface 22.

[0069] The seal 18 and/or the turbine wheel 3 may comprise openings 23 such as cylindrical holes or notches, for instance. The diameter of the holes 23 ranges from 0.5 to 1.5 mm, for instance, is about 0.8 mm, for example. A bracing member 24 is attached, for example by welding, on the radially external periphery of the turbine wheel 3, opposite the impeller wheel 2. The bracing member 24 comprises an axially extending annular part 25, the front end of which is extended by lugs 26 or a rim extending radially inwards. The rim 26 supports a friction lining 27 adapted to come to rest onto the radial part 9 of the cover 5.

[0070] The turbine wheel 3 is able to be axially moved from a disengaged position illustrated in FIGS. 1 and 2, in which the turbine wheel 3 and the impeller wheel 2 are axially moved closer to one another and rotationally uncoupled, and a disengaged position, illustrated in FIGS. 3 and 4, in which the turbine wheel 3 and the impeller wheel 2 are axially separated and in which the rim 26 and the friction lining 27 are supported by the cover 5 so as to rotationally couple the turbine wheel 3, the cover 5 and the impeller wheel 2.

[0071] The motion of the turbine wheel 3 is controlled by pressure chambers positioned on either side of the turbine wheel 3 and separated from one another by the seal 18. The openings 23 make it possible to generate a leakage rate ranging from 0.2 l/min to 5 l/min through the turbine wheel 3 or the seal 18, for instance.

[0072] In the disengaged position, the axial position of the turbine wheel 3 is such that the lip 19 of the seal 18 faces the groove 20 (FIGS. 1 and 2). Thus the seal 18 does not rest on the impeller wheel 2. On the contrary, in the engaged position, the axial position of the turbine wheel 3 is such that the lip 19 of the seal 18 rests on the cylindrical part 7 of the impeller wheel 2, so as to seal the pressure chambers, except for the leakage rate generated by the above-mentioned openings 23 of the seal 18 and/or the turbine wheel 3 (FIGS. 3 and 4).

[0073] It should be noted that the axial clearance j1 between the friction lining 27 and, the radial part 9 of the cover is greater than the clearance j2 between the lip 19 of the seal 18 and the front end of the groove (FIG. 1). The clearance j1 is for example approximately 2 mm and the clearance j2 is for example approximately 1.8 mm. This secures the resting of the lip 19 on the cylindrical surface in the engaged position (FIGS. 3 and 4), It should also be noted that, in case of wear of the friction lining, the clearance j1 is increased, according to the above-mentioned principle.

[0074] The turbine wheel 3 is rotationally coupled to the hub 11 through damping means 28.

[0075] The damping means 28 comprise the annular wheel disc 12 integral with the hub 11, two guiding washers 29, 30 axially positioned on either side of the annular wheel disc 12, and first elastic members 21 acting on the circumference 31 mounted between the annular wheel disc 12 and the guiding washers 29, 30. The first elastic members 31 are adapted to act against the pivoting of the guiding washers 29, 30 relative to the annular wheel disc 12. The damping means 28 further comprise second elastic members 22 acting on the circumference 32, mounted between a linking member 33 attached to the turbine wheel 3, for instance by welding, and the radially external periphery of one of the guiding washers 29, 30, for instance the radially external periphery of the guiding washer 30 opposite the turbine wheel 3. The second elastic members 32 are adapted to act against the pivoting of the guiding washers 29, 30 relative to the turbine wheel 3.

[0076] The first and second elastic members 31, 32 are for instance straight or curved coil compression springs.

[0077] In operation, in the disengaged position of the turbine wheel 3, the torque is transmitted from the crankshaft of the vehicle engine to the cover 5 and to the impeller wheel 2, with such torque being then transmitted to the turbine wheel 3 through the hydrokinetic coupling means formed by the impeller wheel 2, the turbine wheel 3 and the reactor 4. The torque is then transmitted to the hub 11 through the damping means 28. As mentioned above, in this disengaged position, the seal 18 does not rest on the impeller wheel 2 and is positioned axially opposite the groove 20 so that the seal 18 does not rub on the impeller wheel 2 during the relative rotation of the impeller wheel 2 relative to the turbine wheel 3.

[0078] When the turbine wheel 3 is in the engaged position, the torque is directly transmitted from the cover 5 and from the impeller wheel 2 to the turbine wheel 3, without any action from the hydrokinetic coupling means. The torque is then transmitted to the hub 11 through the damping means 28. In this position, the seal 18 rests on the cylindrical part 7 of the impeller wheel 2, with the latter being rotationally coupled to the turbine wheel 3. Since no relative rotation exists between the impeller wheel 2 and the turbine wheel 3, the seal 18 thus does not rub against the impeller wheel 2 either, but simply rests on the matching surface 22 of the impeller wheel 2.

[0079] The turbine wheel 3 moving between the engaged and disengaged positions thereof thus makes it possible to activate or deactivate the hydrokinetic coupling,

[0080] Additionally, the torque converter 1 is adapted to operate in a so-called direct mode, wherein the torque is transmitted from the impeller wheel 2 to the turbine wheel 3. More specifically, in the disengaged position of the turbine wheel 3, i.e. when the hydrokinetic coupling is activated, the impeller wheel 2 turns faster than the turbine wheel 3. Conversely, in a so-called back operation, the turbine wheel 3 can turn faster than the impeller wheel 2.

[0081] The back operation mode is used for instance when the motor brake is used or when the user suddenly takes his/her foot off the accelerator pedal,

[0082] In some operation cases, specifically in the back mode and when the hydrokinetic coupling is activated, the turbine wheel 3 may be axially pushed back opposite the impeller wheel 2. Such a motion of the turbine wheel 3 has to be limited so as to prevent any damage to the torque converter 1, in particular.

[0083] For this purpose, the bracing member 24 is adapted to limit the axial motion of the turbine wheel 3 towards the radial part 9 of the cover 5 opposite the impeller wheel 2.

[0084] According to one embodiment illustrated in FIG. 6, at least one of the guiding washers 29, 30 for example may be provided with pendulum masses 34, movably mounted on the corresponding guiding washer 29, 30. The pendulum masses 34 are preferably positioned on a radially external zone of the corresponding guiding washer 29, 30.

[0085] Using such pendulum masses 34 is more particularly known from documents US14/305128, GB598811, US6026940 and EP1744074.

[0086] According to another embodiment illustrated in FIG. 7, at least one of the guiding washers 29, 30 may, for instance, be equipped with an inertial absorber, consisting of a mass 35 connected to one of the guiding washers 29, 30 by one elastic member 36 able to generate an elastic return torque on either side of a rest position. Using an inertial absorber is known more particularly from document WO2004/018897. The stiffness constant of such elastic member 36 may change or not, and the elastic member may consist of at least one coil spring, for instance.

[0087] According to still another embodiment illustrated in FIG. 8, the damping means 28 may consist of at least one elastically deformable leaf 37 coupled to the turbine wheel 3 or to the hub 11 respectively, at least one bearing member 38 pivotally mounted on a support 39 coupled to the hub 11 or to the turbine wheel 3 respectively, with each leaf 37 being elastically held and radially resting on the corresponding bearing member 38 so as to bend upon rotation of the hub 11 relative to the turbine wheel 3.

[0088] Using such an elastic leaf is more particularly known from document FR3000155.