FR3049022A1 - DOUBLE WET CLUTCH WITH FORCE CENTER TRANSMISSION BODIES - Google Patents

Abstract

The invention relates to a double wet clutch (1) intended to be arranged in a motor vehicle transmission chain, between a motor having a crankshaft and a gearbox comprising two input coaxial shafts (2, 3), said double wet clutch (1) comprising a first and a second clutch (4, 5) which are respectively capable of transmitting a torque of the crankshaft towards one and the other of the two input shafts (2, 3) of the gear box; speeds, each of the first and second clutches (4, 5) comprising: - an inlet disk carrier (8, 9) for coupling in rotation to the crankshaft; an output disk carrier (15, 30) intended to be coupled in rotation to one or the other of the two input shafts of the gearbox; a multi-disk assembly (10, 11) movable between a disengaged position and an engaged position; and - a force transmission member (25, 38) which is movable in translation along the X axis so as to move the multi-disc assembly (10, 11) from its disengaged position to its engaged position; the force transmission members being guided in rotation and centered around the X axis.

Description

DOUBLE WET CLUTCH WITH TRANSMISSION DEVICES

FORCE CENTERS

TECHNICAL FIELD The invention relates to the field of transmissions for a motor vehicle. The invention relates more particularly to a double wet clutch intended to be arranged, in a transmission chain of a motor vehicle, between an engine block and a gearbox comprising two input shafts.

Technological background

A wet double clutch comprises an input hub intended to be secured in rotation to a flywheel attached to the crankshaft of the engine and two clutches each having an inlet disk holder rotatably connected to the input hub, a disk holder an output shaft rotatably connected to one or both of the input shafts of a gearbox and a multi-disk assembly for transmitting torque between the input disk carrier and the disk carrier of output of said clutch when said clutch is in its engaged position. One of the input shafts of the gearbox, rotatably connected to the output disk carrier of one of the clutches, corresponds to the odd gearbox ratios while the other input shaft is connected in rotation to the output disk carrier of the other clutch, corresponds to even reports. Thus, to effect a shift, one of the clutches is moved from its engaged position to its disengaged position while the other clutch is moved from its disengaged position to its engaged position. Such a double clutch thus makes it possible to change speed ratio without breaking torque.

It is known, from DE102014212805, double wet clutches which are actuated by means of a hydraulic control system comprising, a housing, intended to be fixed on the gearbox, having two concentric annular chambers and two axially movable annular pistons. respectively in one and the other of the two annular chambers. Each of the pistons carries a rotating stop which is in abutment against a force transmission member cooperating with one or the other of the two clutches so as to move said clutch between a disengaged position and a position engaged during the movement of the piston. inside its respective annular chamber. Such a control system limits the drag torque and therefore provides satisfactory energy consumption performance.

However, the force transmission members are not centered and guided in rotation about the X axis, which is likely to unbalance the double clutch by generating an unbalance, to affect the homogeneity of the forces exerted between the rotary stops and the force transmission members, to vary the radius of application of the forces on the multi-disk assemblies and to affect the parallelism of the clutch forces exerted by the force transmission members on the multi-disk assemblies.

Such a double clutch is not fully satisfactory. summary

An idea underlying the invention is to solve the disadvantages of the prior art by providing a double wet clutch which is particularly reliable.

According to one embodiment, the invention provides a double wet clutch intended to be arranged in a motor vehicle chain, between a motor having a crankshaft and a gearbox comprising two input coaxial shafts extending in a direction X axis, said double wet clutch comprising a first and a second clutch which are respectively able to transmit a torque of the crankshaft towards one and the other of the two input shafts of the gearbox, each of the first and second clutches comprising: - an input disk carrier for coupling in rotation to the crankshaft; an output disk carrier intended to be coupled in rotation to one or the other of the two input shafts of the gearbox; a multi-disk assembly comprising at least one friction disc integral in rotation with one of the inlet and outlet disk carriers and at least two plates respectively arranged on either side of each friction disk, integral in rotation on the other hand input and output disc carriers, the friction disc and the platens being movable axially between a disengaged position and an engaged position in which said platens pinch said friction disc so as to transmit a torque between the input disk carrier and the output disk carrier; and - a force transmitting member which is movable in translation along the axis X so as to move the multiisque assembly from its disengaged position to its engaged position; said double wet clutch further comprising a control system comprising: - a casing intended to be fixed on the gearbox; - A first and a second annular pistons which are mounted to slide axially on the housing and respectively carry a first and a second rotary stops; the first and second rotational stops cooperating respectively with the force transmitting member of the first and second clutch to move said clutch between its disengaged position and its engaged position; the force transmission members being guided in rotation and centered around the X axis.

Thus, the centering of the force transmission members makes it possible to ensure a balancing of the double wet clutch; a homogeneity of the forces exerted between the rotating stops and the force transmission members; stability of the application radius and parallelism of the forces exerted by the force transmission members on the multi-disk assemblies.

In addition, the hydraulic control system does not require the presence of dynamic seals, which limits the drag torque and, therefore, to limit the energy consumption of the engine.

According to other advantageous embodiments, such a double wet clutch can have one or more of the following characteristics.

The first annular piston is located radially outside the second annular piston.

According to one embodiment, each force transmission member comprises at least one cylindrical centering surface, each of the cylindrical surfaces being circumferentially discontinuous around the axis X. In other words, the centering of the force transmission members It is not carried out continuously around the X axis. Thus, only the cylindrical centering surfaces requiring a large dimensional accuracy, the zones of the force transmission members outside the cylindrical centering surfaces may have greater manufacturing tolerances. , which makes it possible to reduce the manufacturing costs of the force transmission members.

In addition, the geometric interruptions between the cylindrical centering surfaces allow a better circulation of the cooling fluid between the force transmission members.

According to one embodiment, the cylindrical centering surfaces are revolution cylinder portions whose generator is the X axis.

According to one embodiment, the cylinder portions each extend angularly around the X axis over a range of between 5 ° and 45 °.

According to one embodiment, each force transmission member comprises at least three cylinder portions regularly distributed angularly about the X axis, for example distributed every 120 ° when the member has three cylinder portions.

According to one embodiment, the force transmission member of the first clutch and the force transmission member of the second clutch are centered on one another.

According to an advantageous variant, the force transmission members of the first clutch and the second clutch each comprise an inner portion cooperating with one of the first and second rotary stops, an outer portion cooperating with one of the multi-disk assemblies and a cylindrical skirt. centering axial orientation connecting the inner portion and the outer portion; the cylindrical centering skirts of the force transmission members of the first clutch and the second clutch cooperating with each other so as to center the force transmission members one on the other.

According to one embodiment, each input or output disk carrier comprises a cylindrical fluted skirt; each friction disk or plate being axially movably mounted on the cylindrical corrugated skirt of one of the output or inlet disk carriers and integrally rotated therewith; one of the input disk carriers having a support portion directed radially inwardly from an edge of its cylindrical corrugated skirt directed toward the control system; said support portion having a radially inner edge cooperating with a guide bearing in rotation of the double clutch about the X axis.

According to one embodiment, the force transmission member of the second clutch is centered on the support portion. Thus, the centering of the force transmission member of the first clutch is provided by the support portion which is itself centered and guided in rotation about the X axis by means of the guide bearing in rotation of the double clutch.

According to one embodiment, the support portion has an outer portion, an inner portion that is axially offset relative to the outer portion and is disposed within the multi-disk assemblies, and a cylindrical axial centering skirt connecting the outer portion and the inner portion; the force transmission member of the second clutch comprising a cylindrical centering skirt of axial orientation cooperating with the cylindrical centering skirt of the support portion so as to center the force transmission member of the second clutch on the portion of support.

According to an embodiment in which the force transmission members are centered on one another and the force transmission member of the second clutch is centered on a support portion; the force transmitting member of the first clutch and the force transmitting member of the second clutch cooperate with each other via a plurality of cylindrical surfaces regularly distributed about the axis X so as to center the transmitting force on each other, and the second clutch force transmitting member is centered on the support portion via a plurality of cylindrical surfaces which are regularly distributed about the X axis and are circumferentially offset around of the X axis with respect to the cylindrical surfaces through which the force transmission members of the first and second clutches cooperate.

According to one embodiment, the second rotary stop comprises a first ring fixed to the second annular piston, a second ring bearing against the force transmission device of the second clutch and rolling bodies interposed between the first ring and the second ring; the force transmission member of the second clutch being centered on the second ring.

According to an alternative embodiment, the force transmission member of the second clutch comprises a cylindrical centering surface cooperating with a complementary centering cylindrical surface formed on an edge of the second ring.

According to one embodiment, the first rotary stop comprises a first ring fixed to the first annular piston, a second ring bearing against the force transmission device of the first clutch and rolling bodies interposed between the first ring and the second ring and the first ring. power transmission member of the first clutch is centered on the second ring. Thus, the centering of the force transmission member of the first clutch is provided by the first rotary stop which further ensures the rotational guidance of said force transmission member relative to the axis X.

According to a variant, the force transmission member of the first clutch comprises a cylindrical centering surface cooperating with a complementary centering cylindrical surface formed on an edge of the second ring of the first rotary stop.

According to another embodiment, the force transmission member of the first clutch is centered and guided in rotation on the housing of the actuating system.

According to an alternative embodiment, the casing of the actuating system comprises a cylindrical centering surface radially outside the first and second annular pistons and the force transmission member of the first clutch comprises an inner portion cooperating with the first rotary stop, an outer portion and a cylindrical centering skirt axially oriented connecting the inner portion and the outer portion, said cylindrical centering skirt cooperating with the cylindrical centering surface of the casing so as to center and guide in rotation the force transmission member of the first clutch relative to the housing.

According to one embodiment, the housing of the control system comprises an inner tube extending axially about the axis X and providing an internal space for the passage of the two input shafts of the gearbox, the first and the second annular pistons being slidably mounted axially on the casing, outside the inner tube; the support portion being rotatably mounted on the inner tube via said guide bearing.

According to one embodiment, the inner tube extends axially towards the two clutches beyond the first and the second annular chambers.

According to one embodiment, the inner tube is made of material, that is to say formed integrally with the housing.

According to one embodiment, the inner tube has at least one channel for passing a cooling fluid for conducting said cooling fluid to the clutches. Thus, the clutch cooling circuit is integrated with the hydraulic system for controlling the double clutch, which makes it possible to reduce the number of components of the wet double clutch, to reduce its size and contributes to increasing the standardization of its components.

The passage channel of a cooling fluid has an outlet opening opening axially beyond the rotating abutment of the second annular piston irrespective of the position of said second annular piston between its rest position and its active position. Therefore, the circulation of the cooling fluid is particularly effective due to the proper axial positioning of the outlet orifice, which ensures a powerful cooling of the double clutch. In particular, since the passage of the cooling fluid opens out beyond the stroke of the annular pistons between their active position and their rest position, effective cooling of the clutches is ensured regardless of the position of the clutches and in particular when they are closed. positioned at the point of licking and that the cooling requirements are the most important.

According to one embodiment, the inner tube comprises a plurality of cooling fluid passageways distributed circumferentially around the X axis, which ensures efficient and homogeneous cooling. According to one embodiment, the passageways of the cooling fluid are equitably distributed around the X axis.

According to one embodiment, the two clutches are arranged radially one inside the other, which limits the axial size of the double clutch.

According to one embodiment, the input disk carriers are arranged radially outside the outlet disk holder of their respective clutch.

According to one embodiment, the input disk carriers of the two clutches are rotatably mounted about the X axis on the inner tube of the control system via a bearing. Thus, the input disk carriers being supported on the control system, intended to be fixed on the gearbox, the bearing is mounted on a stable and rigid element which is not subjected to axial movements and / or radial, which ensures a stability of the double clutch and a greater reliability of the bearing. In addition, the bearing being mounted on an inner tube having a relatively small diameter, the diameter of the bearing is limited, which reduces its cost, especially if it is a rolling bearing.

According to one embodiment, the bearing is a rolling bearing.

According to one embodiment, the rolling bearing comprises an inner ring which is mounted around the inner tube, an outer ring mounted inside an inlet disk holder housing of one of the clutches and the bodies. rollers interposed between the inner ring and the outer ring.

According to one embodiment, the inner ring is retained on the inner tube in a direction opposite to the control system by an elastic ring which is mounted in a groove on the inner tube.

According to another embodiment, the ring is retained by a shoulder formed directly on the inner tube.

According to one embodiment, the inner tube is secured axially with the housing so that the axial clutch forces exerted by the annular pistons are taken directly by the housing.

According to one embodiment, the rolling bearing is angular contact.

According to one embodiment, the bearing is mounted on a bearing surface of the inner tube, said bearing surface being positioned, in the direction of the two clutches, beyond the races of the first and second annular pistons between their rest position and their position. active position, at least as long as the friction linings of the multi-disk assemblies are not worn.

According to one embodiment, the output disk carriers are fixed to an outlet hub or formed integrally with it, said output hub having grooves cooperating with complementary grooves formed at the end of one either of the input shafts of the gearbox.

According to one embodiment, the cylindrical skirts of the output disk carriers are connected to their respective output hub by a radial portion which extends radially inwardly from an edge of said cylindrical skirt directed in one direction. opposite to the hydraulic control system.

According to one embodiment, the multi-disk assembly of one of the clutches is disposed radially inside the multi-disk assembly of the other clutch and the bearing is disposed radially inside the multi-disk assemblies of the clutches.

According to one embodiment, the multi-disk assembly of one of the clutches is disposed radially inside the multi-disk assembly of the other clutch, the bearing which supports the input disk carriers being arranged radially at the other end. the interior of the multi-disk assemblies of the clutches and the support portion having an inner zone which is folded in a direction opposite to the hydraulic control system, within the multi-disk assemblies.

According to one embodiment, the force transmission member of each of the clutches has an outer periphery equipped with a plurality of axially oriented fingers each passing through the support portion through a respective opening; said fingers being in abutment against the multi-disk assembly of said clutch.

According to one embodiment, each of the force transmission members comprises an inner portion having an axial recess towards the two clutches inside which are at least partially housed the first and second annular pistons of the control system. Such an arrangement also contributes to increasing the axial compactness of the double clutch.

According to one embodiment, the double clutch comprises an inlet hub comprising splines intended to cooperate with complementary splines of an element attached to the crankshaft of the engine, such as a flywheel. The input disk carriers are attached to the input hub, for example via an inlet web.

According to one embodiment, the input disk carriers are arranged radially outside the outlet disk holder of their respective clutch.

According to one embodiment, the invention also provides a motor vehicle comprising a double clutch of the aforementioned type.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be better understood, and other objects, details, features and advantages thereof will become more clearly apparent from the following description of several particular embodiments of the invention, given solely for the purposes of the invention. illustrative and not limiting, with reference to the accompanying drawings. - Figure 1 is a partial sectional view of a double wet clutch according to a first embodiment. - Figure 2 is a partial sectional view of a double wet clutch according to a second embodiment. - Figure 3 is a partial sectional view of a double wet clutch according to a third embodiment. - Figure 4 is a partial sectional view of a double wet clutch according to a third embodiment. - Figure 5 is a rear view of the double wet clutch of Figure 1. - Figure 6 is a partial sectional view in a plane perpendicular to the X axis of the double clutch of Figure 3.

Detailed description of embodiments

In the description and the claims, the terms "external" and "internal" as well as the "axial" and "radial" orientations will be used to designate, according to the definitions given in the description, elements of the double clutch. By convention, the "radial" orientation is directed orthogonally to the X axis of rotation of the double clutch determining the "axial" orientation and, from the inside towards the outside away from said axis, the orientation " circumferential "is orthogonal to the X axis and orthogonal to the radial direction. The terms "external" and "internal" are used to define the relative position of one element relative to another, with reference to the X axis, an element close to the X axis is thus described as internal by opposition an outer member located radially peripherally. Furthermore, the terms "rear" AR and "front" AV are used to define the relative position of one element relative to another in the axial direction, an element intended to be placed close to the engine being designated by before and an element intended to be placed close to the gearbox being designated by the rear.

In connection with Figure 1, there is a dual clutch 1 which is intended to be disposed between an engine block and a gearbox. Such a double clutch 1 is intended to transmit a torque of the crankshaft of the heat engine selectively to one or the other of the two shafts 2, 3 coaxial input of the gearbox. The shaft 2, inside, passes through the housing of the gearbox and extends longitudinally along the axis X. The shaft 3, hollow, also passes through the housing of the gearbox and surrounds the inner shaft 2. The double clutch 1 comprises two clutches 4, 5 which are each intended to temporarily couple the crankshaft of the engine to one of the shafts 2, 3 input of the gearbox. One of the input shafts 2, 3 of the gearbox corresponds to certain gear ratios, for example the odd-speed gears and the reverse gear, and the other corresponds to the other gears, for example example even gear ratios. Thus, to effect a change of speed ratio, one of the clutches 4, 5 is moved from its engaged position to its disengaged position while the other clutch 4, 5 is moved from its disengaged position to its engaged position, so that the engine torque is progressively transferred from one to the other of the clutches 4, 5. Such a double clutch 1 thus makes it possible to change the speed ratio, without breaking the torque, that is to say while maintaining the transmission engine torque to the wheels of the vehicle.

The double clutch 1 comprises an inlet hub 6 which has external splines intended to cooperate with complementary splines formed on an element fixed to the crankshaft of the heat engine, such as a flywheel, single or double, not shown.

The dual clutch 1 is intended to be housed in a clutch housing, not shown, which is fixed on the gearbox. The clutch housing is closed forward by means of a closing cap, not shown, which is guided in rotation on the outer cylindrical surface of the inlet hub 6 by means of a bearing, not shown. The closure cap carries at its outer periphery an annular seal which cooperates with the inner surface of the clutch housing to seal the double clutch 1.

The double clutch 1 also comprises an inlet web 7 which is welded to the inlet hub 6 or formed integrally therewith. The entry web is rotatably connected to an input disk carrier of each of the two clutches 4, 5.

The two clutches 4, 5 each comprise a multidisk assembly 10, 11, that is to say an axial stack of friction discs and trays. The multi-disk assemblies 10, 11 of one and the other of the two clutches are arranged radially one inside the other, so as to limit the axial size of the double clutch 1.

The first clutch 4, that is to say the clutch whose multi-disk assembly 10 is radially outside that of the other clutch 5, comprises an inlet disk carrier 8 which is fixed on the 7. To this end, the inlet web 7 has on its outer periphery an external toothing 12 which cooperates with an internal toothing 13 formed on the inner surface of the inlet disk holder 8 of the first clutch 4 of FIG. in order to join the inlet web 7 in rotation to said inlet disk carrier 8. Furthermore, the inlet web 7 is retained axially rearwardly relative to the inlet disk carrier 8 of the first clutch 4 by means of a stop ring 14. The stop ring 14 is for example an elastic coupling rod which is housed in a groove formed at the front end of the inlet disk holder 8 of the first clutch 4.

The first clutch 4 also includes an output disc holder 15 which is attached to or integrally formed with an outlet hub 16. The output hub 16 is splined and cooperates with complementary splines formed on the outer periphery of the end of one of the input shafts of the gearbox, here the inner shaft 2. Thus, the output hub 16 of the output disk carrier 15 is integral in rotation with the inner shaft 2. The output hub 16 has, at the front, on its outer periphery a shoulder defining an axial bearing surface for a bearing 17. The bearing 17 also cooperates with a shoulder formed on the inner periphery of the inlet hub 6 and defining an axial bearing surface for said bearing 17. The bearing 17 thus ensures the axial positioning of the output disk carrier 15 the first clutch 4 with respect to the inlet web 7. The bearing 17 is for example a rolling bearing.

The inlet disk holder 8 comprises a cylindrical skirt 18 of axial orientation in which is provided an internal toothing and a support portion 19 of annular shape which extends radially inwards from the rear end of the cylindrical skirt 18. The support portion 19 and the cylindrical skirt 18 may be formed in one piece, in the same sheet, as in the embodiment shown, or be formed of two separate pieces attached to each other. 'other. The inlet disk holder 8 is rotatably mounted on the hydraulic control system 21 via a bearing 20, described in more detail below, which cooperates on the one hand with the control system 21 and on the other hand with the radially inner edge of the support portion 19. Advantageously, in order to limit the axial size of the double clutch, the support portion 19 of the input disk carrier 8 comprises an outer portion 19a which has a radial orientation and is disposed at the rear of the multi-disk assemblies 10, 11 of the two clutches 4, 5 and an inner portion 19b which is folded forward and thus extends radially inside the multi-disk assemblies 10, 11.

The output disc holder 15 comprises a cylindrical skirt 22 of axial orientation which is arranged radially inside the cylindrical skirt 18 of the input disc holder 8 and in which is provided an external toothing. The outlet disc holder 15 also has a radially oriented portion 23 which extends radially from the front end of the cylindrical skirt 22 of the output disc holder 15 to the outlet hub 16. The multi-disc assembly 10 comprises a plurality of annular plates, of steel for example, which are integral in rotation with the input disk holder 8 and axially slidably mounted relative to said input disk holder 8. To this end, each plate comprises on its external periphery an external toothing which is in engagement with the internal toothing formed on the internal face of the cylindrical skirt 18 of the input disc holder 8. The multi-disc assembly 10 further comprises a plurality of friction discs which are each interposed between two plates and are integral in rotation with the output disk carrier 15 with an axial translation freedom. To do this, each friction disc has on its inner periphery an internal toothing which is engaged with the external toothing carried by the cylindrical skirt 22 of the output disc holder 15. Each friction disc has friction linings disposed on each of its faces, front and back. The multi-disk assembly 10 is supported forwards against a reaction zone formed on the inlet web 7. The reaction zone is, in the embodiment shown, formed with the aid of an annular rim 24 formed in the vicinity of the outer periphery of the inlet web 7. Furthermore, the plate disposed at the rear end of the multi-disk assembly 10 cooperates with a force transmission member 25. The force transmission member 25 is slidably mounted axially and cooperates with the hydraulic control system 21, described in more detail later, which is adapted to axially slide the force transmission member 25 forward to move the first clutch 4 from its disengaged position towards its engaged position. The force transmission member 25 here consists of a metal sheet which comprises at its outer periphery a plurality of fingers 26 of axial orientation, regularly distributed about the axis X. As shown in FIG. each finger 26 passes through the support portion 19 of the input disk carrier 8 through a dedicated opening 27. Returning to FIG. 1, it can be seen that each finger 26 is thus in abutment with the plate disposed at the rear end of the multi-disk assembly 10 of the first clutch 4.

To move the first clutch 4 from its disengaged position to its engaged position, the force transmission member 25 is moved forward so that each of the friction discs is clamped between two plates and the torque is thus transmitted between the input disk carrier 8 and the output disk carrier 15 and therefore between the crankshaft of the engine and the input shaft 2 of the gearbox. Conversely, when the force transmission member 25 is no longer forced forward, the friction discs and trays find their disengaged position in which they are spaced axially from each other. In order to facilitate the return of the friction discs and plates to their disengaged position, corrugated elastic washers, not shown, are interposed between the plates.

In each gap between two adjacent plates, a spring washer is disposed radially outside the friction disc located in said gap.

In order to limit the axial size of the double clutch 1, the force transmission member 25 comprises at its inner portion an axial recess 28 forwards inside which is, at least partly, housed the system. hydraulic control 21.

The second clutch 5, that is to say the clutch whose multi-plate assembly 11 is disposed radially inside that of the other clutch 4, has a similar structure to the first clutch. The second clutch 5 comprises an inlet disk carrier 9 integral in rotation with the inlet web 7. To do this, the inlet disk carrier 9 of the second clutch 5 is fixed, for example by welding, to the portion of support 19 of the input disk carrier 8 of the first clutch 4. The input disk carrier 9 has a cylindrical skirt 29 of axial orientation which is arranged radially inside the cylindrical skirt 22 of the output disk carrier 15 of the first clutch 4. The cylindrical skirt 29 has an internal toothing.

The second clutch 5 also includes an outlet disk carrier 30 which is attached to or is integrally formed with an outlet hub 31. The outlet hub 31 has internal splines which cooperate with complementary splines formed on the outer periphery of the end of one of the input shafts of the gearbox, here the outer shaft 3. In order to ensure the axial positioning of the output disk carrier 30, a first axial bearing 32 is interposed between the output hub 16 of the first clutch 4 and the output hub 31 of the second clutch 5 and a second axial bearing 33 is interposed between the hub of output 31 of the second clutch 5 and an inner tube 42 of the hydraulic control system 21.

The outlet disc holder 30 comprises a cylindrical skirt 34 of axial orientation, arranged radially inside the cylindrical skirt 29 of the inlet disc holder 9 and having external toothing. The outlet disc holder 30 also has a radially oriented portion 35 which extends radially from the front end of the cylindrical skirt 34 of the output disc holder 30 to the outlet hub 31. The multi-disc assembly 11 of the second clutch 5 comprises a plurality of annular plates having a structure similar to that of the annular plates of the first clutch 4. Each plate has on its outer periphery an external toothing which cooperates with the complementary toothing formed on the internal face of the cylindrical skirt 29 of the input disc holder 9. The multi-disc assembly 11 further comprises a plurality of friction discs which have a structure similar to those of the first clutch 4 and are mounted integral in rotation with the output disc holder 30 and sliding axially on it. To do this, each friction disc has on its inner periphery an internal toothing which is in engagement with the external toothing formed on the cylindrical skirt 34 of the output disc holder 30. Each friction disc is interposed between two plates.

The plate disposed at the front end of the multi-disk assembly 11 cooperates with a reaction member 36. The reaction member 36 is in turn held forward by means of a stop ring 37 which is attached to the input disk carrier 9 of the second clutch 5, at the front end of its cylindrical skirt 34.

The second clutch 5 is actuated by means of a force transmitting member 38 which, on the one hand, cooperates with the plate disposed at the rear end of the multi-disk assembly 11 of the second clutch 5 and, on the other hand , cooperates with the hydraulic control system 21 which is able to slide axially forwardly so as to move the second clutch 5 from its disengaged position to its engaged position. The force transmitting member 38 here consists of a metal sheet which comprises at its outer periphery a plurality of axially oriented fingers 39 regularly distributed around the axis X. Each finger 39 passes through a dedicated opening formed in the support portion 19 of the input disk carrier 8 of the first clutch 4 and is thus in abutment against the plate disposed at the rear end of the multi-disk assembly 11 of the second clutch 5.

To move the second clutch 5 from its disengaged position to its engaged position, the force transmitting member 38 is moved forwardly so that each of the friction discs is clamped between two platens and the torque is thereby transmitted between the input disk carrier 9 and the output disk carrier 30 and therefore between the crankshaft of the engine and the external shaft 3 input of the gearbox.

In order to limit the axial size of the double clutch, the force transmission member 38 comprises at its inner portion an axial recess 40 forwards inside which is, at least partly, housed the hydraulic system order 21.

The double clutch 1 further comprises a hydraulic control system 21 for actuating the two clutches 4, 5. The hydraulic control system 21 comprises a housing 41 which is fixed against a wall of the gearbox, not shown. The housing 41 has an inner tube 42 extending axially about the axis X and providing an internal space through which pass the shafts 2, 3 input of the gearbox. The inner tube 42 is made of material with the casing 41. The casing 41 also has first and second concentric annular chambers 43, 44 arranged radially outside the inner tube 42. First and second pistons 45, 46 of annular shape are respectively movably mounted in axial translation inside the first and second chambers 43, 44.

The housing 41 further has, for each of the first and second chambers 43, 44, a channel 47, 48 for supplying pressurized fluid opening into said chamber 43, 44 so as to allow its supply of fluid. Each of the channels 47, 48 is connected to a hydraulic circuit equipped with a pump. The first and second chambers 43, 44 are thus intended to be supplied with fluid to cause the piston 45, 46 to move forward from its rest position to its active position.

Each of the first and second pistons 45, 46 carries a rotary stop 49, 50 which is fixed to the end of said piston 45, 46. Each rotary stop 49, 50 has a first ring 59, 60 which is fixed to the piston 43, 44 a second ring 61, 62 bearing against one of the force transmission members 25, 38 and rolling bodies, such as balls, interposed between the two rings.

The inner tube 42 extends axially forwardly beyond the first and second chambers 43, 44. Furthermore, beyond the stroke of the first and second pistons 45, 46 corresponding to the displacement of the first and second clutches 4 5 of their disengaged position towards their engaged position, the inner tube 42 has a cylindrical bearing surface 51 on which is mounted the bearing 20 supporting the input disk carriers 8, 9 of the clutches 4, 5. The bearing 20 is here a rolling bearing comprising an inner ring which is mounted around the cylindrical bearing surface 51 of the inner tube 42, an outer ring which is mounted inside a housing 52 formed at the radially inner edge of the portion support 19 of the inlet disk holder 8 of the first clutch 4 and the rolling bodies, such as balls, interposed between the outer ring and the inner ring. The rolling bearing is angular contact. The housing 52 has, rearwardly a shoulder 53 for retaining the outer ring backwards. Furthermore, the inner ring is held forward by an elastic ring 54 of the "circlip" type which is mounted in a groove in the inner tube 42, in front of the cylindrical bearing surface 51. The outer diameter of the cylindrical bearing surface 51 is smaller than the internal bore of the force transmitting member 38.

In the embodiment illustrated in FIG. 1, the force transmission member 38 of the second clutch 5 is centered on the force transmission member 25 of the first clutch 4. Furthermore, the force transmission member 25 of the first clutch 4 is centered on the second ring 61 of the first rotary stop 49.

To do this, the force transmission members 25, 38 each have a cylindrical centering skirt 63, 64 which has an axial orientation. The cylindrical centering skirts 63, 64 each connect the inner portion and the outer portion of their respective force transmission member 25, 38 and thus provide the axial recess 28, 40 forward of the inner portion. The cylindrical centering skirts 63, 64 cooperate with each other so as to center the force transmission members 25, 38 relative to each other. The cylindrical centering skirt 63 of the force transmission member 25 of the first clutch 4 is disposed radially outside the cylindrical centering skirt 64 of the force transmission member 38 of the second clutch 4 so that the inner surface of the cylindrical centering skirt 63 cooperates with the outer surface of the cylindrical centering skirt 64.

According to one embodiment, the cylindrical centering skirts 63, 64 have a cylindrical shape of revolution about the axis X. In other words, the centering cylindrical skirts 63, 64 cooperate with each other. continuously around their entire periphery around the X axis.

According to another embodiment, the cylindrical centering skirts 63, 64 cooperate with each other on dedicated centering cylindrical surfaces which are discontinuous around the X axis and are regularly distributed around the X axis. This embodiment will be described in more detail later with reference to FIGS. 3 and 6.

The axial dimensions of the cylindrical centering skirts 63, 64 and their relative positioning are such that: firstly, the first piston 45 can move to its active position corresponding to an engaged state of the first clutch 4 whereas the second piston 46 remains in its rest position without the force transmission member 25 of the first clutch 4 comes to bear axially against the force transmission member 38 of the second clutch 5; and that - secondly, the second piston 46 can move to its active position corresponding to an engaged state of the second clutch 5 while the first piston 45 remains in its rest position without guiding between the two skirts cylindrical centering 63, 64 is interrupted.

Furthermore, the force transmission member 25 of the first clutch 4 has an annular projection 65 formed in its inner portion and projecting rearwardly. A cylindrical centering surface is thus formed on the radially inner periphery of the annular projection 65. This cylindrical centering surface cooperates with a complementary centering cylindrical surface which is formed by a radially outward end of the second ring 61 of the first rotary stop 49. The annular projection 65 may be formed continuously all around the X axis or consist of a plurality of annular segments which are circumferentially spaced from each other and evenly distributed about the X axis.

According to other embodiments not shown, the centering of the force transmission member 25 of the first clutch 4 on the second ring 61 of the rotary stop 49 may be provided by means of different shapes.

In this embodiment, the rotational guidance of two force transmission members 25, 38 with respect to the axis X is thus ensured by means of the rotary stopper 49 of the first clutch 4.

This embodiment is particularly advantageous in that, in operation, the two force transmission members 25, 38 and the second ring 61 of the first rotary stop 49 have an identical speed, namely that of the crankshaft, so that the rotational guidance of the two force transmission members 25, 38 is ensured without generating an additional friction torque, which thus limits the drag torque and moderates the energy consumption.

Figure 2 illustrates another embodiment in which each of the force transmission members 25, 38 is centered on the rotary stop 49, 50 with which it cooperates. The force transmission member 25 of the first clutch 4 is produced in accordance with what has previously been described in relation to FIG. 1. In FIG. 2, the force transmission member 38 of the second clutch 5 also comprises a projection ring 66 protruding rearwardly. The annular projection 66 has, on its inner periphery, a cylindrical centering surface which cooperates with a complementary cylindrical centering surface which is formed by a radially outwardly directed end of the second ring 62 of the second rotary stopper 60.

FIGS. 3 and 6 illustrate another embodiment in which the force transmission member 38 of the second clutch 5 is centered on the support portion 19 and the force transmission members 25, 38 of the two clutches 4, 5 are centered on each other.

As in the embodiment of FIG. 1, the force transmission members 25, 38 each have a cylindrical centering skirt 63, 64 and said cylindrical centering skirts 63, 64 cooperate with each other so as to centering the force transmission members 25, 38 relative to each other.

Furthermore, the support portion 19 comprises a cylindrical centering skirt 67 having an axial orientation and connecting the outer portion 19a and the inner portion 19b of the support portion 19. The cylindrical centering skirt 67 has an inner surface which cooperates with the outer surface of the cylindrical centering skirt 64 of the force transmission member 38 of the second clutch 5 to ensure the centering thereof.

In this embodiment, in addition to the rules for axial dimensioning and relative positioning of the centering cylindrical skirts 63, 64 of the force transmission members 25, 38 defined above, the axial dimension and the positioning of the cylindrical centering skirt 67 of FIG. the support portion 19 are such that the second piston 46 can move to its active position without the force transmission member 25, 38 of the second clutch 5 comes into abutment against the support portion 19.

In relation to the cross-sectional view of FIG. 6, the structure of the centering cylindrical skirts 63, 64 and 67 according to one embodiment is observed. The cylindrical centering skirt 67 has three centering tabs 69a, 69b, 69c which are oriented radially inwards and are evenly distributed around the axis X. The surface of the centering lugs 69a, 69b, 69c which is directed towards the inside has the shape of a revolution cylinder portion whose generator is the X axis and cooperates with the outer surface of the cylindrical centering skirt 64 of the force transmission member 38 of the second clutch 5. Each centering lug 69a, 69b, 69c extends circumferentially over an angular sector between 5 and 45 °.

Furthermore, the cylindrical centering skirt 64 of the force transmission member 38 also comprises three centering tabs 70a, 70b, 70c which are oriented radially inwards and are regularly distributed around the axis X. Each leg 70a, 70b, 70c circumferentially extends on an angular sector Y between 5 and 45 ° and is circumferentially offset, by an angle Z, with respect to the angular sector of the centering tabs 69a, 69b, 69c of the skirt cylindrical centering 67 of the support portion 19. Furthermore, the cylindrical centering skirt 63 of the force transmission member 25 of the first clutch 4 also comprises three centering lugs 71a, 71b, 71c which are oriented radially towards 'outside. The surface of the inwardly facing centering tabs 70a, 70b, 70c cooperates with the surface of the centering tabs 71a, 71b, 71c which is outwardly oriented to center the force transmission members 25, 38 in relation to each other. The centering tabs 70a, 70b, 70c and 71a, 71b, 71c vis-a-vis cooperate with each other via surfaces having the shape of a portion of a cylinder of revolution whose generator is the X axis .

In the embodiment of FIG. 4, the force transmission member 25, 38 of the first clutch 4 is centered and guided in rotation on the housing 41 of the actuating system 21 while the force transmission members 25, 38 of the two clutches 4, 5 are centered on one another.

As in the embodiment of Figures 1 and 3, the force transmission members 25, 38 each have a cylindrical centering skirt 63, 64 of axial orientation and said cylindrical centering skirts 63, 64 cooperate with each other. other so as to center the force transmission members 25, 38 relative to each other.

Furthermore, the housing 41 has on its radially outer periphery a cylindrical centering surface 68 which cooperates with the internal surface of the cylindrical skirt 63 of the force transmission member 25 of the first clutch 4 so as to center and guide in rotation said force-transmitting member 25 with respect to the axis X. In order to guide the force-transmitting member 25 in rotation with respect to the casing 41, the cylindrical centering surface 68 has the shape of a cylinder of revolution whose generator is the axis X. In an embodiment not shown, a smooth annular bearing is disposed between the force transmission member 25 and the housing 41 to limit friction. Such an annular bearing may in particular be made of plastic material, such as polytetrafluoroethylene (PTFE) for example.

Of course, other arrangements are possible to ensure a centering and rotational guidance of the force transmission members 25, 38 with respect to the X axis. In particular, the characteristics of the four aforementioned embodiments can be combined.

Also, in another alternative embodiment, not shown, the force transmission member 38 of the second clutch 5 is centered on the second ring 62 of the second rotary stop 50 and the force transmission members of the two clutches 25, 38 are centered on each other.

In another embodiment, the force transmission member 38 of the second clutch 5 is centered on the second ring 62 of the second rotary stop 50 and the force transmission member 25 of the first clutch 4 is centered and guided by rotation on the casing 41 of the actuating system 21.

In another embodiment, the force transmitting member 38 of the first clutch 4 is centered on the second ring 61 of the first rotary stop 49 and the force transmitting member of the second clutch is centered on the support portion. 19.

In yet another embodiment, the force transmission member 38 of the first clutch 4 is centered and guided in rotation on the housing 41 of the actuating system and the force transmission member 38 of the second clutch 5 is centered. on the support portion 19.

Returning to FIG. 1, it can be seen that the inner tube 42 of the hydraulic control system 21 comprises a plurality of channels 55 for the passage of a cooling fluid, such as gearbox oil, intended to provide the cooling and lubrication of the multi-disk assemblies 10, 11. The channels 55 are equitably distributed around the X axis.

Each channel 55 extends axially between an inlet orifice 56 opening at the rear face of the housing 41 of the hydraulic control system and an outlet orifice 57 opening at the front end of the inner tube 42. The orifices input 55 are connected to a hydraulic circuit equipped with a pump. The outlet orifices 57 are regularly distributed around the X axis and open radially inside the multi-disk assemblies 10, 11. The outlet orifices 57 are directed radially outwards in order to guide the cooling fluid radially towards the outside. In the illustrated embodiment, the outlet orifices 57 open axially at a portion of the inner tube extending beyond the cylindrical bearing surface 51 on which is 20. The coolant then passes between the input disk carriers 8, 9 and the output disk carriers 15, 30.

In order to allow oil to flow from the outlet ports to the outside of the double clutch, passing through the multi-disk assemblies 10, 11, the cylindrical skirts 29, 34 of the inlet and outlet disk carriers 9, 30 of the second clutch 5 and the cylindrical skirts 18, 22 of the inlet and outlet disc holders 8, 15 of the first clutch 4 have radial orifices 58. In FIG. 1, only the orifices 58 of the exit disc holder 30 of the second clutch 5 are visible.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is not limited thereto and that it comprises all the technical equivalents of the means described and their combinations if they are within the scope of the invention. The use of the verb "to include", "to understand" or "to include" and its conjugated forms does not exclude the presence of other elements or steps other than those set out in a claim.

In the claims, any reference sign in parentheses can not be interpreted as a limitation of the claim.

Claims (18)

1. Double wet clutch (1) intended to be arranged in a motor vehicle transmission chain, between a motor having a crankshaft and a gearbox comprising two axially-extending coaxial input shafts (2, 3) X, said double wet clutch (1) comprising a first and a second clutch (4, 5) which are respectively capable of transmitting a torque of the crankshaft towards one and the other of the two input shafts (2, 3) of the gearbox, each of the first and second clutches (4, 5) comprising: - an input disk carrier (8, 9) intended to be coupled in rotation to the crankshaft; an output disk carrier (15, 30) intended to be coupled in rotation to one or the other of the two input shafts of the gearbox; a multi-disk assembly (10, 11) comprising at least one friction disc integral in rotation with one of the input and output disk carriers (8, 9, 15, 30) and at least two plates respectively arranged on each side of each friction disk, integral in rotation with the other of the inlet and outlet disk carriers (8, 9, 15, 30), the friction disk and the plates being movable axially between a disengaged position and an engaged position in which said trays pinch said friction disk so as to transmit a torque between the input disk carrier (8, 9) and the output disk carrier (15, 30); and - a force transmission member (25, 38) which is movable in translation along the X axis so as to move the multi-disc assembly (10, 11) from its disengaged position to its engaged position; said double wet clutch (1) further comprising a control system (21) comprising: - a housing (41) for attachment to the gearbox; - a first and a second annular pistons (45, 46) which are mounted to slide axially on the housing (41) and respectively carry a first and a second rotary stops (49, 50); the first and second rotational stops (49, 50) cooperating respectively with the force transmitting member (25, 38) of the first and second clutch (4, 5) to move said clutch (4, 5) between its disengaged position and its engaged position,; the force transmission members (25, 38) being guided in rotation and centered around the X axis. A dual wet clutch (1) according to claim 1, wherein each force transmitting member (25, 38) has at least one cylindrical centering surface, each of the centering cylindrical surfaces being circumferentially discontinuous about the X axis. . The dual wet clutch (1) according to claim 2, wherein the cylindrical centering surfaces are cylinder portions. 4. Double wet clutch (1) according to claim 3, wherein the cylinder portions each extend angularly about the X axis over a range of between 5 ° and 45 °. A dual wet clutch (1) according to claim 3 or 4, wherein each force transmitting member (25, 38) has at least three cylinder portions evenly distributed angularly about the X axis. A dual wet clutch (1) according to any one of claims 1 to 5, wherein the force transmitting member (25) of the first clutch (4) and the force transmitting member (38) of the second clutch (5) are centered on one another. A dual wet clutch (1) according to claim 6, wherein the force transmitting members (25, 38) of the first clutch (4) and the second clutch (5) each have an inner portion cooperating with one of the first and second rotary stops (49, 50), an outer portion cooperating with one of the multi-disk assemblies (10, 11) and a cylindrical centering skirt (63, 64) of axial orientation connecting the inner portion and the outer portion and wherein the cylindrical centering skirts (63, 64) of the force transmitting members (25, 38) of the first clutch (4) and the second clutch (5) cooperate with one another so as to center the force transmission members (25, 38) on each other. A dual wet clutch (1) according to any one of claims 1 to 7, wherein each inlet or outlet disk carrier (8, 9, 15, 30) comprises a cylindrical corrugated skirt (18, 22, 29, 34); each friction disk or plate being axially movably mounted on the cylindrical corrugated skirt of one of the output or inlet disk carriers and integrally in rotation therewith and in which one of the disk carriers is inlet (8, 9) has a support portion (19) directed radially inwardly from an edge of its cylindrical corrugated skirt directed towards the control system; said support portion (19) having a radially inner edge cooperating with a bearing (20) for rotating the double clutch about the X axis, and wherein the force transmission member (38) of the second clutch ( 5) is centered on the support portion (19). A double wet clutch (1) according to claim 8, wherein the support portion (19) has an outer portion (19a), an inner portion (19a) which is axially offset from the outer portion (19a) and is disposed within the multi-disk assemblies (10, 11), and an axially oriented cylindrical centering skirt (67) connecting the outer portion (19a) and the inner portion (19b) and in which the transmission member of force (38) of the second clutch (5) comprises a cylindrical centering skirt (64) axially oriented cooperating with the cylindrical centering skirt (67) of the support portion (19) so as to center the body of the power transmission (38) of the second clutch (5) to the support portion (19). A dual wet clutch according to claim 8 or 9 taken in combination with claim 6 or 7, wherein the force transmitting member (25) of the first clutch (4) and the force transmitting member (38). of the second clutch (5) cooperate with one another via a plurality of cylindrical surfaces regularly distributed about the axis X so as to center the force transmission members (25, 38) on one another and wherein the force transmitting member (38) of the second clutch (5) is centered on the support portion (19) via a plurality of cylindrical surfaces which are regularly distributed about the X axis and are circumferentially offset around the X-axis with respect to the cylindrical surfaces through which the force-transmitting members (25, 38) of the first and second clutches (4, 5) co-operate. 11. Double wet clutch (1) according to any one of claims 1 to 7, wherein the second rotary stop (50) comprises a first ring (60) attached to the second annular piston (46), a second ring (62). in abutment against the force transmission device (38) of the second clutch (5) and of the rolling bodies interposed between the first ring and the second ring and in which the force transmission member of the second clutch (5) is centered on the second ring (62). 12. Double wet clutch (1) according to claim 11, wherein the force transmitting member (38) of the second clutch (5) comprises a cylindrical centering surface (66) cooperating with a complementary centering cylindrical surface formed on an edge of the second ring (62). A dual wet clutch (1) according to any one of claims 1 to 7, wherein each inlet or outlet disk carrier (8, 9, 15, 30) comprises a cylindrical corrugated skirt (18, 22, 29, 34); each friction disk or plate being axially movably mounted on the cylindrical corrugated skirt of one of the output or inlet disk carriers and integrally in rotation therewith and in which one of the disk carriers is inlet (8, 9) has a support portion (19) directed radially inwardly from an edge of its cylindrical corrugated skirt directed towards the control system; said support portion (19) having a radially inner edge cooperating with a bearing (20) for rotating the double clutch about the X axis, and wherein the force transmission member (38) of the second clutch ( 5) is centered on the support portion (19). The double wet clutch (1) according to claim 13, wherein the support portion (19) has an outer portion (19a), an inner portion (19a) which is axially offset from the outer portion (19a) and is disposed within the multi-disk assemblies (10, 11), and an axially oriented cylindrical centering skirt (67) connecting the outer portion (19a) and the inner portion (19b) and in which the transmission member of force (38) of the second clutch (5) comprises a cylindrical centering skirt (64) axially oriented cooperating with the cylindrical centering skirt (67) of the support portion (19) so as to center the body of the power transmission (38) of the second clutch (5) to the support portion (19). 15. Double wet clutch (1) according to any one of claims 1 to 14, wherein the first rotary stop (49) comprises a first ring (59) attached to the first annular piston (45), a second ring (61). bearing against the force transmission device (25) of the first clutch (4) and the rolling bodies interposed between the first ring (59) and the second ring (61) and in which the force transmission member (25) of the first clutch (4) is centered on the second ring (61). The dual wet clutch (1) according to claim 15, wherein the force transmitting member (25) of the first clutch (4) has a cylindrical centering surface (65) cooperating with a complementary centering cylindrical surface formed on an edge of the second ring (61) of the first rotary stop (49). 17. Double wet clutch (1) according to claim any one of claims 1 to 14, wherein the force transmission member (25) of the first clutch (4) is centered and guided in rotation on the housing (41). ) of the actuating system (21). Double wet clutch (1) according to claim 17, wherein the housing (41) of the actuating system (21) has a cylindrical centering surface (68) radially outside the first and second annular pistons ( 45, 46), wherein the force transmission member (25) of the first clutch (4) has an inner portion cooperating with the first rotary stop (49), an outer portion and a cylindrical centering skirt (63) of axial orientation connecting the inner portion and the outer portion and wherein said cylindrical centering skirt (63) cooperates with the cylindrical centering surface (68) of the housing (41) so as to center and guide in rotation the transmission of force (25) of the first clutch (4) relative to the housing (41).