FR3123097A1 - Disc carrier assembly and double wet clutch including this disc carrier assembly - Google Patents

Abstract

Assembled disc carrier and double wet clutch comprising this assembled disc carrier Assembled torque input disc carrier (50) for double wet clutch comprising: - a central hub (51) with an axis of rotation (X) comprising a cylindrical portion (52) and a flange (53), - an annular disc support (10) comprising an external spline (101) arranged to receive the multi-disc assembly of a first clutch (E1), the free end (103) of the disc support being provided with the external spline (101) and the other end being provided with a flange (104) resting on the flange, the disc support and the flange of the central hub are fixedly assembled by a first welded connection (60), the outer diameter of the external spline being offset radially with respect to the first welded connection, and in that the disc support (10) and the flange (53) are assembled by fastening means additional (70) offset radially with respect to the first welded connection (60). Figure for abstract: Figure 2

Description

Disc carrier assembly and double wet clutch including this disc carrier assembly

The present invention relates to an assembled disc carrier and a double wet clutch comprising this assembled disc carrier. The invention also relates to a triple wet clutch comprising this assembled disc carrier.

The present invention relates to the field of torque transmission chains for motor vehicles, in particular arranged between a combustion engine and a gearbox.

The invention relates more specifically to a triple wet clutch for a motor vehicle of the hybrid type in which a rotating electrical machine is arranged in the torque transmission chain.

In the state of the art, motor vehicles of the hybrid type are known comprising a double wet clutch arranged between an internal combustion engine and a gearbox, a rotating electrical machine as well as a torque cut-off clutch otherwise called “K0 clutch”. An actuating member of this torque cut-off clutch makes it possible to couple or uncouple in rotation a crankshaft of the internal combustion engine to a rotor of the rotating electrical machine. Thus, it is possible to cut the internal combustion engine each time the vehicle stops and to restart it thanks to the rotating electrical machine. The rotating electrical machine can also act as an electric brake or provide a surplus of energy to the internal combustion engine to assist it or prevent it from stalling. When the internal combustion engine is running, the electrical machine can act as an alternator. The rotating electrical machine can also drive the vehicle independently of the internal combustion engine.

Patent application EP 1678429 A1 discloses a double wet clutch for a motor vehicle, comprising torque input means intended to be coupled to a crankshaft, a first torque output shaft, a second torque output shaft, a first clutch capable of coupling or decoupling the torque input means and the first torque output shaft, a second clutch capable of coupling or decoupling the torque input means and the second torque output shaft. The first and second clutches, respectively of the multi-disc type, are arranged radially one above the other. Each of the multi-disc clutches is rotated by a common torque input disc carrier rotatably linked to the crankshaft.

The input disc carrier in this case comprises a cylindrical hub and a disc support common to the first and second clutches. The disc support comprises in particular an external spline supporting the multi-disc assembly of the first clutch and an internal spline supporting the multi-disc assembly of the second clutch. The disc support is attached to the cylindrical hub by a recessed connection which is offset radially with respect to the support of the multi-disc assemblies. This connection supports significant forces and must withstand high shear and bending stresses. The mechanical reliability of such a connection also depends on the actuation forces generated within the double clutch. The repetition of the efforts is in this case doubled since the torque input disc carrier is common to the two clutches. The fatigue resistance of such a connection is problematic.

US patent application 5388474 discloses a method for assembling disc carriers on a ring-shaped hub. This process proposes to assemble by laser welding the disc support on an outer surface of the hub. This welding process enables end-to-end assembly of the inner periphery of the disc carrier and the outer bearing surface of the hub, but imposes a very small clearance between parts due to the absence of filler material and the sharpness of the beam from the laser source. Obtaining by stamping and press-cutting the disc support does not make it possible to obtain precise parts, which makes it difficult to place the parts end to end. The constraints of the laser process impose reduced flatness defects and a small clearance between parts. Otherwise, the laser weld may then present unacceptable appearance defects. It is sometimes necessary to machine the internal periphery of the disc support so that the clearance between parts becomes compatible with the laser welding process.

In addition, under actuation force, the welded connection supports significant forces and must withstand high shearing and bending stresses given that this connection is offset radially with respect to the support of the multi-disc assembly. The fatigue resistance of such a connection is also problematic.

The object of the invention is in particular to provide a simple, effective and economical solution to this problem.

The object of the present invention is in particular to propose an assembled disc carrier for a double wet clutch making it possible to solve at least in part the drawbacks mentioned of the prior art.

For this purpose, the invention proposes, according to one of its aspects, an assembled torque input disc carrier for a double wet clutch comprising:
- a central hub with axis of rotation X comprising a cylindrical portion and a flange extending radially from the cylindrical portion,
- an annular disc support comprising a spline arranged to receive the multi-disc assembly of a clutch, the free end of the disc support being provided with the spline and the other end being provided with a collar resting on the flask,
in which the disc support and the flange of the central hub are fixedly assembled by a first welded connection located on the internal periphery of the flange, the outer diameter of the spline being offset radially with respect to the first welded connection, and in that the disk support and the flange are assembled by means of additional fixings offset radially with respect to the first welded connection.

This assembled disc holder, according to the invention, has the advantage, thanks to the positioning of the first welded connection and the additional fixing means on two different installation diameters, of distributing the bending and shearing stresses over two zones of separate fixing. The disc support rests on the flange of the central hub thanks to the collar, which simplifies the axial positioning of the spline relative to said central hub, said spline being able to be arranged outside or inside the disc support. This assembled disc carrier, according to the invention, has the advantage of reducing the geometric defects of the assembly by welding.

Advantageously, the spline of the disc support can be an external spline arranged to receive the multi-disc assembly of a first clutch, the external diameter of the external spline being offset radially with respect to the first welded connection.

Preferably, the first welded connection is made on a first implantation diameter, the additional fastening means are made on a second implantation diameter, the second implantation diameter being arranged radially between the first implantation diameter and the outer diameter of the outer spline. This positioning of the first welded connection and the additional fixing means on two different installation diameters makes it possible to distribute the bending stress mainly on the additional fixing means and the shear stress on the first welded connection.

According to one embodiment of the invention, the first implantation diameter may be strictly less than the second implantation diameter. This layout is particularly suited to the double wet clutch having a radial architecture for which radial compactness is sought.

According to another embodiment of the invention, the first implantation diameter may be strictly greater than the second implantation diameter.

Preferably, an annular groove opening radially outwards can be formed by the combination of surfaces coming from the disc support and the flange, the annular groove being arranged axially between the flange and the external spline. Reinforcing the connection of the disc support on the central hub makes it possible to radially offset the external spline of the first clutch with respect to the central hub. The bending stresses generated by this radial offset are not retransmitted within the first welded connection. It is thus possible to install the balancing chamber of the first clutch on an annular space of larger diameter.

Advantageously, the disc support may comprise on its free end an internal spline arranged to receive the multi-disc assembly of a second clutch. This arrangement is particularly suited to the double wet clutch having a radial architecture for which radial compactness is sought.

Preferably, the flange of the disc support may comprise a flat surface of annular shape resting on a flat surface of the flange as well as the internal periphery centered on an edge of the flange. The positioning of the outer spline of the first clutch is improved by using a geometric reference formed by the flat bearing face of the flange. This assembled disc carrier, according to the invention, has the advantage of reducing the geometric defects of the assembly by welding.

By internal periphery is meant a part of the part located close to the axis of rotation of the clutch device.

In all of the above, the first welded connection may be a continuous 360° weld made with or without addition of material, for example laser welding.

As a variant, the first welded connection can be a series of discontinuous weld beads distributed angularly around the axis X, the weld being carried out with or without addition of material, for example laser welding.

According to another variant, the spline of the disc support may be an internal spline arranged to receive the multi-disc assembly of a second clutch, the outer diameter of the internal spline being offset radially with respect to the first welded connection.

The invention may have one or other of the characteristics described below combined with each other or taken independently of each other:

According to one embodiment of the invention, the additional fastening means may be discontinuous weld beads, produced by laser welding by transparency, the weld passing through the collar of the disc support.

Preferably, the discontinuous weld beads can be made in an arc of a circle, the curvilinear length of all the discontinuous weld beads being less than the curvilinear length of the first welded connection.

Advantageously, the ratio of the curvilinear length of the first welded connection divided by the curvilinear length of all the discontinuous weld beads is greater than or equal to 1.2.

The additional fixing means are, for example, six discontinuous weld beads made according to an arc of a circle of 40° and spaced angularly every 60°.

According to another embodiment of the invention, the additional fastening means may be spot welds distributed angularly around the axis of rotation, for example made by transparency welding. In this embodiment, the spot weld passes through the flange of the disk carrier.

According to another embodiment of the invention, the additional fastening means may be rivets distributed angularly around the axis of rotation, the rivets passing through the collar and the flange. In this embodiment, the rivets are arranged under the annular groove of the assembled disc carrier.

The invention also relates, according to another of its aspects, to a double wet clutch for a torque transmission system comprising:
- A first clutch;
- a second clutch arranged radially inside the first clutch, the first and second clutches being controlled to selectively couple a driving shaft to a first driven shaft and to a second driven shaft, for example a first and a second gearbox shafts speeds, and
- an assembled torque input disc carrier incorporating all or part of the characteristics mentioned above, in which the disc carrier is common to the first clutch and to the second clutch.

This double wet clutch according to the invention has the advantage, thanks to the positioning of the first welded connection and the additional fixing means on two different installation diameters, of distributing the bending and shearing stresses on two distinct fixing zones. . The reliability of the wet double clutch is thus improved.

Preferably, the first clutch of the double wet clutch can comprise:
- A first torque output disc carrier arranged to be connected in rotation to a first driven shaft;
- A multi-disc assembly comprising friction discs and plates driven in rotation by the assembled torque input disc carrier and the first output disc carrier;
- an axially movable actuating piston which is controlled in movement by means of a control chamber and a balancing chamber, said actuating piston alternately clamping axially in an engaged position the multi-disc assembly against means of reaction disposed on the free end of the outer spline of the disk carrier and axially release the multi-disc assembly in a disengaged position, the balancing chamber being housed in the annular groove of the assembled disk carrier.

This double wet clutch according to the invention has the advantage, thanks to the positioning of the balancing chamber within the annular groove of the assembled disc carrier, of reducing its overall size. Reinforcing the connection of the disc support on the central hub makes it possible to radially offset the external spline of the first clutch with respect to the central hub. The bending stresses generated by this radial offset are not retransmitted within the first welded connection. It is thus possible to install the balancing chamber of the first clutch on an annular space of larger diameter.

Within the meaning of the present application, a wet clutch is a clutch which is adapted to operate in an oil bath.

The invention also relates, according to another of its aspects, to a triple wet clutch for a torque transmission system comprising a torque cut-off clutch of the multi-plate type, controlled to selectively couple a shaft driving an electric machine, and a double wet clutch incorporating all or part of the characteristics mentioned above, the torque cut-off clutch being arranged radially beyond the double wet clutch.

Advantageously, the triple wet clutch may include the assembled disc carrier of the double wet clutch which is also common to the torque cut-off clutch, said assembled disc carrier comprising an annular cavity disposed radially beyond the double wet clutch and arranged to receive an actuating piston of the torque cut-off clutch, said assembled disc carrier comprising an attached drive cover and arranged to be driven in rotation by an electric machine, the drive cover forming part of the cavity annular.

Advantageously, the drive cover can surround the outer periphery of the flange.

Thanks to this triple wet clutch architecture, the clutches are concentric and arranged radially in the same plane. The axial bulk of such a triple wet clutch within a torque transmission system or a torque transmission chain is thus reduced.

According to one embodiment, the drive cover may comprise an electrical connection zone capable of being linked in rotation with an electrical machine rotating around an axis parallel to the axis of rotation X. The electrical connection zone may be axially offset from the cut-off clutch and/or the first and second clutches. The electric machine is then said to be “off-line”.

Preferably, the drive cover may comprise a spline arranged to receive the multi-disc assembly of the torque cut-off clutch, said spline being made in one piece with the drive cover or attached to the drive cover.

Advantageously, the drive cover may comprise a toothed ring adapted to be connected in rotation with an electrical machine rotating around an axis parallel to the axis of rotation X.

This arrangement makes it possible to position the electric machine according to the space available in the torque transmission chain of the vehicle. This arrangement makes it possible in particular not to have to arrange the electric machine axially following the clutches, which would be negative for the axial compactness. This arrangement makes it possible in particular not to have to arrange the electric machine radially beyond the clutches, which would be negative for the radial compactness.

Alternatively, a chain or a belt can be used to connect the rotating electrical machine to the electrical connection area.

The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the following description of a particular embodiment of the invention, given solely by way of illustration and not limiting, with reference to the appended figures.

- the shows an axial sectional view of a triple wet clutch according to a first embodiment of the invention.

- the shows an isometric view of the assembled disc carrier according to the first embodiment of the invention of the .

- the shows a detail view in axial section of the disc holder assembled according to the first embodiment of the invention of the

- the shows a detail view in axial section of a disc holder assembled according to a second embodiment of the invention.

In the remainder of the description and the claims, the terms "front" or "rear" will be used, without limitation and in order to facilitate understanding, depending on the direction with respect to an axial orientation determined by the main axis X of rotation of the transmission of the motor vehicle and the terms "inner/inner" or "outer/outer" with respect to the X axis and in a radial orientation, orthogonal to said axial orientation.

There is shown in Figures 1 to 3 a first embodiment of an assembled disc carrier 50 torque input according to the invention integrated within a triple wet clutch 1. The triple wet clutch 1 is shown in within a motor vehicle torque transmission chain via a gearbox housing 110 fitted with two driven torque output shafts A1, A2.

On the , there is a triple wet clutch 1 comprising:
- a multi-disc type K0 torque cut-off clutch, controlled to selectively couple a shaft leading to an electric machine,
- a first torque output clutch E1 and a second torque output clutch E2 respectively of the multi-disc type, controlled to selectively couple the electric machine and/or the driving shaft to a first driven shaft and to a second driven shaft, the first and second clutches E1, E2 being arranged radially one above the other, and
- an assembled disc carrier 50 having the function of introducing the torque within the clutches and the other function of supplying oil to the control chambers of the torque cut-off clutch K0, of the first clutch E1 and of the second clutch E2.

The first clutch E1 is of the multi-disc type, operates in a humid environment and comprises the assembled disc carrier 50 according to the first embodiment of the invention.
The assembled disc carrier 50 comprises a central hub 51 with an axis of rotation X comprising:
- a cylindrical portion 52,
- a flange 53 extending radially from the cylindrical portion 52,
- a first annular cavity 56 arranged on the side of the flange and arranged to receive an actuating piston 15 of the first clutch E1,
- a second annular cavity 55 arranged on the same side of the flange as the first annular cavity and arranged to receive an actuating piston 25 of the second clutch E2,
- a third annular cavity 57 arranged radially beyond the other two annular cavities and arranged to receive an actuating piston 5 of the torque cut-off clutch K0, and
- Oil pipes 54a, 54b and 54c formed in the central hub 51 passing through the cylindrical portion 52 and the flange 53, and emerging separately into the annular cavities.

The annular cavities 57, 56, 55 of the torque cut-off clutch K0, of the first clutch E1 and of the second clutch E2 are oriented in the same direction, for example in the direction of the drive shaft, i.e. say in the direction of the heat engine of the torque transmission chain. The annular cavities serve as a control chamber for the respective clutches.

The triple wet clutch 1 comprises around its axis of rotation X at least one torque input element 2 which is connected in rotation to a drive shaft (not shown). Input element 2 is located in front of triple wet clutch 1.

In the first embodiment, the input element 2 generally having an "L" shape, comprises a radially oriented part formed by a torque input veil 3 and an axially oriented part formed by a torque input hub 4. The torque input element 2 is guided in rotation inside a box 111 fixed with respect to the torque transmission chain.

The torque input input element 2 is for example linked in rotation by means of splines formed at the output of a damping device (such as a double damped flywheel, etc.) whose input is linked, in particular by means of a flywheel, to the drive shaft formed by a crankshaft which is driven in rotation by a heat engine fitted to the motor vehicle.

The torque input veil 3 comprises, at its outer radial end, a spline arranged to receive the multi-disc assembly of the torque cut-off clutch K0.

In the example considered, the triple wet clutch 1 further comprises a torque cut-off clutch K0 coupling selectively and by friction the torque input disc 3 and an intermediate disc carrier 81 of the torque cut-off clutch K0 integral in rotation with the assembled disc carrier 50.

The K0 torque cut-off clutch comprises a multi-disc assembly comprising several friction discs 7, equipped with friction linings, integral in rotation with the torque input web 3, several plates 6 respectively arranged on either side of each friction disc 7, integral in rotation with the intermediate disc carrier 81. The torque cut-off clutch K0 is actuated by an actuating piston 5 which is axially movable, here from the rear to the front, between a disengaged position and an engaged position which correspond respectively to the open and closed states of the torque cut-off clutch K0. The actuating piston 5 pinches the friction linings so as to transmit a torque between the torque input veil 3 and the intermediate disc carrier 81.

The plates 6 of the multi-disc assembly of the torque cut-off clutch K0 are connected in rotation to the assembled disk carrier 50 by means of a groove and the friction disks 7 connected in rotation to the element of entry 2.

The assembled disc holder 50 comprises a drive cover 80 attached to the outer periphery of the flange 53. In the present case, the drive cover 80 partly forms the annular cavity 57. The assembled disc holder 50 has the function to transmit the torque within the triple wet clutch 1. For this, the drive cover 80 is integral in rotation with the intermediate disc holder 81, in this case by means of a welded connection.

The drive cover 80 includes an electrical connection zone 82 able to be connected in rotation with a rotating electrical machine. In the present case, the electric machine rotates around an axis parallel to the axis of rotation X. The electric machine is said to be "off-line" because it is not concentric with the transmission shaft but aligned according to a parallel shaft. The electrical connection zone 82 is capable of cooperating directly with a pinion of the rotary electrical machine.

The electrical connection zone 82 can be made in the form of a crown capable of being meshed directly by a pinion or indirectly (belt, chain, etc.) of the rotating electrical machine (not visible). The crown may have helical toothing of a shape complementary to the pinion of the rotary electrical machine.

The assembled disk carrier 50 is able to transmit the torque coming from two separate sources, thermal and electrical. When the torque cut-off clutch K0 is closed, the torque from the thermal engine can then be transmitted to the coaxial shafts A1, A2 of the gearbox depending on the closing of one or the other of the first clutch E1 or the second clutch E2.

The first driven shaft A1 is driven in rotation when said first clutch E1 is closed and the second driven shaft A2 is driven in rotation when said second clutch E2 is closed.

The multi-disc assembly of the first clutch E1 comprises plates 11 connected in rotation to a disk support 10 attached to the assembled disk carrier 50 and friction disks 12 connected in rotation to a first output disk carrier 13. The disks 12 of friction are individually axially interposed between two successive plates 11.

The first output disc carrier 13 of the first clutch E1 is connected in rotation by meshing with the friction discs 12 and by a splined connection with said first driven shaft A1. The inner radial end of the first output disc carrier 13 is secured to a splined output hub.

The multi-disc assembly of the second clutch E2 comprises plates 21 connected in rotation to the disk support 10 attached to the assembled disk carrier 50 and friction disks 22 connected in rotation to a second output disk carrier 23. The disks 22 friction are individually axially interposed between two successive plates 21.

The second output disc carrier 23 of the second clutch E2 is connected in rotation by meshing with the friction discs 22 and by a splined connection with said second driven shaft A1. The inner radial end of the second output disc carrier 23 is secured to a splined output hub.

As illustrated on the , the disc carrier 10 of annular shape comprises an external spline 101 which meshes with the multi-disc assembly of the first clutch E1 and an internal spline 102 which meshes with the multi-disc assembly of the second clutch E2. The disc support 10 common to the first clutch E1 and to the second clutch E2 is fixedly assembled to the central hub 51 via a first welded connection 60 located on the inner periphery 106 of said disc support. In this configuration, the disc support 10 and the first welded connection 60 must withstand a number of actuations multiplied by two compared to a standard case where the disc supports are separate.

In a variant not shown, the internal and external splines meshing with the multi-disc assemblies of the clutches E1 and E2 can be distributed over two separate disc supports and attached to the central hub.

As illustrated in FIGS. 1 and 2, the outer diameter de1 of the outer spline 101 of the disc support 10 is offset radially with respect to the first welded connection 60. Each time the first actuating piston 15 of the first clutch E1 or of the second actuating piston 25 of the second clutch E2, the first welded connection 60 undergoes high shear and bending stresses. The outer diameter de1 corresponds to the largest measurable diameter on the outer spline 101. In this first embodiment, the outer diameter de2 of the outer spline 102 of the disc carrier 10 is also offset radially with respect to the first welded connection 60. The outer diameter de2 corresponds to the largest diameter measurable on the inner spline 102.

In this first embodiment of the invention, the disk support comprises a free end 103 provided with the external groove 101 and another end provided with a flange 104 resting on the flange 53. The flange 104 comprises in particular a surface ring-shaped planar resting on a planar surface 59 of the flange and an internal periphery 106 centered on a rim 58 of the flange. The first welded connection 60 is located on the internal periphery 106 of the flange 104. This positioning of the flange 104 on the flange 53 has the advantage of reducing the geometric defects of the assembly by welding.

The first welded connection 60 is a continuous 360° weld made by laser welding without adding material. In order to avoid the deterioration of the first welded connection 60, the disc support and the flange are also assembled by means of additional fixings offset radially with respect to the first welded connection. In this first embodiment, the additional fastening means 70 are discontinuous weld beads 71, produced by laser welding by transparency. The solder notably passes through the collar 104 of the disk support.

This double wet clutch according to the invention has the advantage, thanks to the positioning of the first welded connection 60 and the additional fixing means 70 on two different installation diameters, of distributing the bending and shearing stresses over two zones of separate fixing.

The first welded connection 60 is made on a first implantation diameter d1, the additional fastening means 70 are made on a second implantation diameter d2, the second implantation diameter d2 being disposed radially between the first implantation diameter d1 and the outer diameter de1 of the outer spline 101. More specifically, the first implantation diameter d1 is strictly less than the second implantation diameter d2. In this way, the bending stress is mainly taken up by the additional fastening means 70 and the shearing stress is taken up by the first welded connection 60. The reliability of the double wet clutch is thus improved.

According to this first embodiment, the discontinuous weld beads 71 are made in an arc of a circle and the curvilinear length of all the discontinuous weld beads 71 is less than the curvilinear length of the first welded connection 60. There are six beads discontinuous welds 71 made according to an arc of a circle of 40° and spaced angularly every 60°. The discontinuous weld beads 71 extend circumferentially at an angle of 240°.

For a better distribution of shear and bending stresses, the ratio of the curvilinear length of the first welded connection divided by the curvilinear length of all the discontinuous weld beads is greater than or equal to 1.2.

In a variant not shown, the first implantation diameter may be strictly greater than the second implantation diameter. In this case, the first welded connection is arranged radially beyond the outer diameter of the outer spline.

From a general operating point of view, the triple wet clutch 1 is hydraulically controlled by means of a pressurized fluid, generally oil.

To selectively control the change of state of the torque cut-off clutch K0, of the first clutch E1 and of the second clutch E2, a triple wet clutch control device manages the pressurized oil supply within control chambers separated. The control device is generally integrated into the gearbox housing 110. The control device is connected to the central hub 50 which comprises oil pipes 54a, 54b and 54c under pressure, for example three in number as represented on the . The oil pipes 54a, 54b and 54c are distributed angularly around the cylindrical portion 52 of the central hub 50.

Each of the oil pipes 54a, 54b and 54c consist of substantially radial and axial bores directed in the direction of the control chambers of the torque cut-off clutch K0, of the first and second clutches E1, E2.

For example, the oil pipe 54c whose inlet is located axially at the rear end of the cylindrical portion 52 is associated with the control chamber 55 of the second clutch E2. The oil pipe 54c is produced by drilling successive axial and radial pipes within the central hub 51. The pipes emerge into each other and are arranged to supply pressurized fluid to the control chamber of the second clutch E2. The oil pipe 54c opens into the second annular cavity 55 formed partly by the cylindrical portion 52 of the central hub 51 and partly by the disc support 10 attached to the flange 53.

The second clutch E2 comprises an actuating piston 25 which is axially movable, here from rear to front, between a disengaged position and an engaged position which correspond respectively to the open and closed states of the second clutch E2. The multi-disc assembly of the second clutch E2 is actuated directly by the second actuating piston 25 made from stamped sheet metal. The actuating piston 25 is axially movable relative to the second annular cavity 55 of the central hub 51. The actuating piston 25 is controlled in movement by means of a control chamber delimited in part by the disk support 10.

The oil pipe 54b machined in the central hub 51 is associated with the control chamber of the first clutch E1. The oil pipe 54b is produced by drilling successive axial and radial pipes within the central hub 51. The pipes emerge into each other and are arranged to supply pressurized fluid to the control chamber 56 of the first clutch E1. The oil pipe 54b opens into the first annular cavity 56.

The first clutch E1 comprises an actuating piston 15 which is axially movable, here from rear to front, between a disengaged position and an engaged position which correspond respectively to the open and closed states of the first clutch E1. The actuating piston 15 is controlled in movement by means of a control chamber 56 and a balancing chamber 91, said actuating piston 15 alternately clamping axially in an engaged position the multi-disc assembly against means reaction 19 arranged on the free end 103 of the outer spline of the disc carrier and axially release the multi-disc assembly in a disengaged position. The reaction means 19 can for example be an elastic ring.

In the first embodiment, the oil pipes 54a, 54b and 54c open onto the outer periphery of the flange 53 and are closed by the drive cover 80.

As is known in the operation of a wet clutch, a balancing chamber is associated with each control chamber. The balancing chambers are supplied with fluid, for example cooling fluid. Coolant enters channels separate from oil lines 54a, 54b and 54c. These separate channels are also formed in the central hub 51.

In order to facilitate the control of the actuating piston 15, the first clutch E1 uses the balancing chamber 91 supplied with cooling fluid. The balancing chamber 91 is arranged radially beyond the control chamber 55 of the second clutch E2. To improve the compactness of the double wet clutch, the balancing chamber 91 is arranged in an annular groove 105 emerging radially outwards and formed in the assembled disc holder 50.

The annular groove 105 is formed by the combination of surfaces coming from the disc support 10 and the flange 53. Advantageously, the annular groove 105 is arranged axially between the flange 53 and the external spline 101. The reinforcement of the connection of the disc support 10 on the central hub 51 allows the external spline 101 of the first clutch E1 to be offset radially with respect to the central hub 51. The bending stresses generated by this radial offset are not transmitted within the first welded connection 60. It is thus possible to install on an annular space of larger diameter the balancing chamber 91 of the first clutch E1.

We will now present other embodiments of the assembled disc carrier 50. All of these assembled disc carriers 50 perform the same functions of transmitting torque, supporting the friction discs and conveying oil under pressure to the within a wet clutch.

The presents an assembled disc carrier 50 according to a second embodiment of the invention similar to the first embodiment at least in its general operation.

This second embodiment differs from that exposed with reference to FIGS. 1 to 3 in that the additional fixing means 70 are rivets 72 distributed angularly around the axis of rotation X. The rivets 72 pass through the flange 104 of the discs 10 and flange 53.

In this embodiment, the rivets 72 are arranged under the annular groove 105 of the assembled disc carrier 50. The first welded connection 60 is made on a first implantation diameter d1, the rivets 72 are arranged on a second diameter of implantation d2, the second implantation diameter d2 being arranged radially between the first implantation diameter d1 and the external diameter de1 of the external spline 101. More precisely, the first implantation diameter d1 is strictly less than the second diameter d' implantation d2. In this way, the bending stress is mainly taken up by the rivets 72 and the shearing stress is taken up by the first welded connection 60. The reliability of the double wet clutch is thus improved.

According to a third embodiment of the invention, the additional fixing means 70 are spot welds distributed angularly around the axis of rotation, for example made by transparency welding. In this third embodiment, the spot weld passes through the flange of the disk carrier.

According to a fourth embodiment of the invention, the first welded connection 60 is a series of discontinuous weld beads distributed angularly around the axis X, the weld being carried out with or without addition of material, for example laser welding.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

It is understood on reading the foregoing that the present invention proposes a triple wet clutch in which the clutches are concentric and arranged radially in the same plane. The axial size of such a triple wet clutch within a torque transmission chain is reduced. This triple wet clutch includes an assembled disc carrier in which the mechanical strength of the disc carrier on the central hub is improved.

The invention cannot however be limited to the means and configurations described and illustrated here, and it also extends to any equivalent means or configuration and to any technical combination operating such means. In particular, the shape of the assembled disk holder can be modified without harming the invention, insofar as these components, ultimately, fulfill the same functions as those described in this document.

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

Claims (18)

Torque input assembled disc carrier (50) for double wet clutch comprising:
- a central hub (51) of axis of rotation (X) comprising a cylindrical portion (52) and a flange (53) extending radially from the cylindrical portion (52),
- an annular disc support (10) comprising a groove (101, 102) arranged to receive the multi-disc assembly of a clutch (E1, E2), the free end (103) of the disc support being provided with the groove (101, 102) and the other end being provided with a collar (104) resting on the flange,
characterized in that the disc support (10) and the flange (53) of the central hub are fixedly assembled by a first welded connection (60) located on the internal periphery (106) of the flange (104), the external diameter ( de1, de2) of the spline (101, 102) being offset radially with respect to the first welded connection, and in that the disc support (10) and the flange (53) are assembled by additional fixing means (70 ) radially offset from the first welded connection (60). Disc carrier assembly (50) according to Claim 1, in which the spline of the disc carrier (10) is an external spline (101) arranged to receive the multi-disc assembly of a first clutch (E1), the outer diameter ( de1) of the external spline (101) being offset radially with respect to the first welded connection (60). Assembled disc carrier (50) according to the preceding claim, in which the first welded connection (60) is produced on a first implantation diameter (d1), the additional fixing means (70) are produced on a second diameter of implantation (d2), the second implantation diameter (d2) being arranged radially between the first implantation diameter (d1) and the external diameter (de1) of the external spline (101). Assembled disc holder (50) according to the preceding claim, in which the first implantation diameter (d1) is smaller than the second implantation diameter (d2). Assembled disc holder (50) according to one of Claims 2 to 4, in which an annular groove (105) emerging radially outwards is formed by the combination of surfaces originating from the disc support (10) and from the flange (53), the annular groove (105) being arranged axially between the flange and the outer spline (101). Assembled disc holder (50) according to one of Claims 2 to 5, in which the disc support (10) comprises on its free end (103) an internal groove (102) arranged to receive the multi-disc assembly of a second clutch (E2). Assembled disc carrier (50) according to one of Claims 1 to 6, in which the collar (104) of the disc carrier comprises a flat surface of annular shape resting on a flat surface (59) of the flange as well as the periphery internal (106) centered on a flange (58) of the flange. Assembled disc carrier (50) according to one of Claims 1 to 7, in which the first welded connection (60) is a continuous 360° weld made with or without addition of material, for example laser welding. Assembled disc carrier (50) according to one of Claims 1 to 7, in which the first welded connection (60) is a series of discontinuous weld beads distributed angularly around the axis (X), the weld being made with or without addition of material, for example laser welding. Assembled disc carrier (50) according to one of Claims 1 to 9, in which the additional fixing means (70) are discontinuous weld beads (71), produced by laser welding by transparency, the weld passing through the collar ( 104) from the disc support. Assembled disc carrier (50) according to the preceding claim, in which the discontinuous weld beads (71) are made in an arc of a circle, the curvilinear length of the set of discontinuous weld beads (71) being less than the curvilinear length of the first welded connection (60). Assembled disc carrier (50) according to the preceding claim, in which the ratio of the curvilinear length of the first welded link (60) divided by the curvilinear length of the set of discontinuous weld beads (71) is greater than or equal to 1.2. Assembled disc holder (50) according to one of Claims 1 to 9, in which the additional fixing means (70) are spot welds distributed angularly around the axis of rotation, for example made by transparency welding. Assembled disc carrier (50) according to one of Claims 1 to 9, in which the additional fixing means (70) are rivets (72) distributed angularly around the axis of rotation, the rivets passing through the collar (104 ) and the flange (53). Disc carrier assembly (50) according to Claim 1, in which the spline of the disc carrier (10) is an internal spline (102) arranged to receive the multi-disc assembly of a second clutch (E2), the outer diameter ( de2) of the internal spline (102) being offset radially with respect to the first welded connection (60). Double wet clutch (E1, E2) for torque transmission system including:
- a first clutch (E1);
- a second clutch (E2) arranged radially inside the first clutch (E1), the first and second clutches being controlled to selectively couple a driving shaft to a first driven shaft and to a second driven shaft, for example a first and a second gearbox shaft, and
- an assembled disc holder (50) for torque input according to one of the preceding claims, in which the disc support (10) is common to the first clutch (E1) and to the second clutch (E2). Double wet clutch (E1, E2) according to the preceding claim taken in combination with claim 5, in which the first clutch (E1) comprises:
- a first torque output disc carrier (13) arranged to be connected in rotation to a first driven shaft (A1);
- a multi-disc assembly comprising friction discs (12, 22) and plates (11, 21) driven in rotation by the assembled torque input disc carrier (50) and the first output disc carrier (13) ;
- an axially movable actuating piston (15) which is controlled in movement by means of a control chamber (56) and a balancing chamber (91), said actuating piston (15) alternately clamping axially in an engaged position the multi-disc assembly against reaction means (19) arranged on the free end of the external spline (101) of the disc support (10) and release axially in a disengaged position the multi-disc assembly, the balance chamber (91) being housed in the annular groove (105) of the assembled disc holder (50). Triple wet clutch for a torque transmission system comprising a torque cut-off clutch (K0) of the multi-plate type, controlled to selectively couple a shaft driving an electric machine, and a double wet clutch (E1, E2) according to one of claims 16 or 17, the torque cut-off clutch (K0) being arranged radially above the double wet clutch (E1, E2).