CN113757269A - Wet-type double clutch - Google Patents

Abstract

A dual wet clutch (1) for torque transmission comprising: a first (E1) and a second (E2) multi-disc clutch, the two clutches (E1, E2) being positioned one above the other radially about the rotation axis (X), the first clutch (E1) comprising a first disc carrier (10) adapted to support a multi-disc assembly of said first clutch (E1), the first clutch being actuated by a first actuating piston, the movement of which is controlled by a control chamber (32), a balance chamber (31) being associated with the control chamber (32), a balance cover (70) defining a balance chamber (31) of the first clutch (E1), the second clutch (E2) comprising a second disc carrier (20) adapted to support a multi-disc assembly of the second clutch (E2), the second disc carrier (20) being rigidly connected to the first disc carrier (10) so as to rotate together with the first disc carrier, wherein the balancing cover (70) is axially retained between the first disk holder (10) and the second disk holder (20).

Description

Wet-type double clutch

Technical Field

The present invention relates to a wet double clutch for a vehicle transmission system, for example of the hybrid type, in which a rotating electric machine is located in the torque transmission line.

Background

As is known, each wet dual clutch mechanism comprises a first and a second clutch of the multi-plate type, supported by a clutch hub, and a first and a second actuator capable of generating a force to configure the first and the second clutch respectively in an engaged or disengaged configuration by means of a piston. Each clutch includes an axially movable piston that in turn moves the first friction disk relative to the second friction disk to configure the corresponding clutch in one or the other of the above configurations.

The displacement of the piston is controlled by a control chamber associated with an equilibrium chamber delimited at least by an equilibrium cover which must contain a quantity of hydraulic fluid, called coolant, which supplies the equilibrium chamber, which lubricates the components and compensates for the axial forces generated by the movable piston. Such balance covers necessarily impose limitations on the design, positioning, centering, fastening and footprint within the dual clutch.

In the current development of vehicle hybrids, there is a need for a torque transmission line incorporating an electrical power source, however, that does not affect the axial and radial compactness of the torque transmission line. The current solutions are not entirely satisfactory. Due to the presence of the wet clutch, there is a need to design a wet dual clutch such that fluid can be provided to the different clutches without changing the footprint of the torque transfer lines. The pursuit of axial and radial compactness forms the basis of the present invention.

The present invention aims to improve the existing designs by providing a wet double clutch which makes it possible to coordinate the requirements of axial and radial compactness, while ensuring a satisfactory supply of fluid to the clutch and its actuating piston.

Disclosure of Invention

To this end, according to one aspect of the invention, the invention proposes a wet double clutch for torque transmission, comprising:

a first clutch and a second clutch, respectively of the multi-disk type, positioned one above the other radially around the axis of rotation,

the first clutch comprises a first disc holder adapted to support a multi-disc assembly of the first clutch, the first clutch being actuated by a first actuating piston, the movement of the first actuating piston being controlled by a control chamber, the balancing chamber being associated with the control chamber,

a balance cover defining a balance chamber of the first clutch,

the second clutch comprises a second disc carrier adapted to support a multi-disc assembly of the second clutch, the second disc carrier being rigidly connected to the first disc carrier for rotation therewith,

wherein the balance cap is axially retained between the first disk holder and the second disk holder.

Due to the balancing cover supported on the first and second disc holders, no additional space needs to be provided for receiving a seal or any other component or fastening method for keeping the balancing cover in an axial position. Such a wet double clutch has the advantage of a reduced radial footprint, while at the same time the retention of the balance cap is axially simplified, which is achieved jointly by the first and second disk carriers being rigidly connected to each other. This interaction between the components optimally ensures the positioning of the balancing cover, for example in order to accommodate a fluid volume.

Advantageously, the balancing cover is axially supported on a portion of the first disc holder and on a portion of the second disc holder, the axial support taking place on either side of the balancing cover and defining a support area. As a result, the balance cover is axially interposed between and supported by the two disk holders. In other words, the first and second disc holders are supported positioned on either side of the balancing cover in their respective support areas on either side of the balancing cover. The components have the advantage of being axially positioned or stacked on top of each other in order to optimize the assembly steps.

The invention may have one or other of the features described below in combination with each other or considered independently of each other:

the portions of the first and second disc holders may be annular, respectively. Alternatively, one portion may comprise segments of material angularly distributed about the axis X;

the portion of the second disc holder may be a radially inner portion of the second disc holder;

the support region of the second disk carrier, the balancing cover and the support region of the first disk carrier can be positioned axially one after the other. In other words, each support area is located on one side or the other of the balancing cover. The support areas are thus axially close to each other in order to concentrate their forces at the same location on each side of the balancing cover, thereby improving axial retention, for example on the inner end of the balancing cover.

The support area of the first disc holder may be made by machining or pressing;

the support area of the second disc holder can be made by machining or pressing;

preferably, the support area may be a flat surface adapted to receive one end of the balancing cover;

the first and second disc holders may be torque input disc holders;

as a variant, the first and second disk holders may be torque output disk holders;

the first disc holder, which is cylindrical, may comprise an internal spline supporting the multi-disc assembly of the first clutch and a web extending radially inwards with respect to the axis X, said portion of the first disc holder being formed by the web. The web may be integrally formed with the first disc holder;

the balancing cover can be supported on the web in the support region of the first disk carrier;

the cylindrical second disc carrier may comprise internal splines supporting the multi-disc assembly of the second clutch and a collar at the end of the splines, said part of the second disc carrier forming said collar;

the collar can be supported on the balance cap in the support region of the second disk holder;

-a weld connecting said portions of the first and second disc holders is formed on the edge of the collar;

the collar may be continuous. The collar may extend from the radially inner end of the spline, for example towards the axis X. In this case, the welding is performed on the inner end of the collar;

the collar and a portion of the balancing cover may have complementary shapes;

the butt welding may be laser welding, with fusion of the edges of the portions of the first and second disc holders, without any additional manufacturing costs or additional filling material. Alternatively, the welding may be capacitor discharge welding;

the balancing cap may further comprise a skirt adapted to interact with the collar so as to center said skirt on the second disc holder. Here, the advantage is that the centering surface of the second disk holder is increased;

the first disc carrier may be a subassembly comprising an internal spline supporting the multi-disc assembly of the first clutch and a central hub, the internal spline and the central hub being rigidly connected for common rotation, said portion of the first disc carrier being formed by the central hub. Preferably, the central hub supports the first clutch and the second clutch together.

The central hub may comprise a flange extending radially with respect to the axis X, the balancing cover being supported on the flange of said portion. The central hub may include an oil supply passage through the cylindrical portion and the flange and into the balance chamber of the first clutch. The advantage of such a central hub is that oil is supplied to the first clutch;

advantageously, the oil supply channels may be arranged in the same plane through the flange. This facilitates its integration into the wet double clutch and its production. Therefore, the axial footprint of such wet dual clutches is reduced;

preferably, the oil supply channel may be present at the periphery of the flange and may be closed by the inner cylindrical surface of the drive cap. Therefore, a part of the oil supply passage can be sealed without using other expensive components;

preferably, the oil supply channel may be created by drilling a continuous conduit into the central hub, said conduits entering each other and being arranged to supply the control chamber of the first clutch with pressurized fluid. The fluid may be oil, such as transmission oil.

The balancing cover may comprise a first support face oriented along the axis X towards the first disc holder and a second support face oriented along the axis X towards the second disc holder, the first and second support faces being located on an inner circumference of the balancing cover;

the first support face may be received on a support area of the first disk holder portion;

the second support face may be received on a support area of the second disc holder portion;

the balancing cover may be positioned radially inside the first disc holder;

the balancing cover may be positioned radially above the second disc holder;

for example, the portion of the first disc holder may comprise an annular rim on which the balancing cover is centered and the support area. Advantageously, the annular rim may extend angularly at least 280 degrees, for example 360 degrees, about the axis X;

the first and second support surfaces of the balancing cover may be radially delimited between the internal spline of the second disc holder and the annular rim of the first disc holder;

the collar may surround the annular rim. In the tunnel, an annular rim may surround the collar. In any case, this has the advantage of retaining and centering the collar;

the annular rim may be obtained by forging, machining or pressing said portion of the first disc holder;

the annular rim may be integrally formed with said portion of the first disc holder. As a variant, the annular rim may be attached to the first disc holder, for example fastened by welding;

in another example, the portion of the first disc holder may comprise a series of angularly distributed pressing bosses, and a series of support areas formed on each of the bosses, the balancing cover being centered on the bosses. Advantageously, the bosses may be discontinuous;

preferably, the bosses may be angularly distributed about the axis X, in a uniform distribution;

the collar may surround a series of pressed bosses. This has the advantage of radially retaining the collar;

in the preceding example, said portion of the first disk support holds the balancing cover in its supporting area and additionally centers the balancing cover together with the first and second disk supports on said annular rim or on said pressing boss;

the annular rim or the series of pressed bosses may be positioned radially below the splines of the first disc holder. An annular rim or a series of stamped bosses may be positioned radially inside the balancing cap. As a variant, the annular rim or the series of pressed bosses can be positioned radially outside the balancing cap;

the annular rim may have a shape complementary to that of the balancing cover, for example a smooth or toothed profile, so as to improve the retention of said cover by means of a shape or nested fit;

the balancing cover may comprise an opening adapted to receive the boss of the first disc carrier, with the advantage of improved fastening by form fit, having an open or closed profile;

the portion of the second disc holder may be attached to the portion of the first disc holder, e.g. fastened together by welding. The weld seam may be circumferentially continuous about the axis X, in particular at the ends of the component;

the portion of the second disc holder may be attached to the annular rim or the series of pressed bosses, e.g. fastened by welding. The weld may be circumferentially continuous about the axis X;

as a variant, the weld seam may be discontinuous about the rotation axis X, for example formed by a plurality of weld beads angularly distributed about the axis X. The advantage of the weld bead is that a material gap or opening is created in the assembly of the first and second disc holders;

preferably, the weld is at an end of the component. As a result, welding can be performed on the inner or outer periphery of the annular rim, or on the edge of the pressed boss;

in a first example, the portion of the second disc holder may be attached to the annular rim, for example by welding or alternatively by being fastened together end to end by form fit. Alternatively, the portion of the second disc holder may be attached to the series of pressed bosses, for example by welding;

in another example, said portion of the second disc holder may be fastened to said annular rim by means of a clip or a snap. In other words, it may be secured by a clip, such as an elastic ring;

an advantage of the above-described assembly example is that the first and second disc holders are rigidly connected for common rotation, while the balancing cover is held axially fixedly between them.

The annular rim or the series of pressed bosses may be positioned radially below the portion of the second disc holder or, as a variant, radially above the portion of the second disc holder;

the portion of the first disc holder may comprise a recess adapted to receive an elastic ring, the second disc holder being rotated by a boss of the portion and being axially retained by the elastic ring received in the recess of the portion. The advantage is that the parts are assembled by axial fixing, without welding, the partial bosses making it possible to connect the first and second disc holders by form-fitting;

the elastic return element, which may be supported on or formed with the balancing cap, is for example an elastic washer or an elastic return means;

the elastic restoring element can be positioned radially above the second disk carrier;

for example, an elastic gasket may be supported between the cover and the first disc holder;

for example, the balancing cover may form in part an elastic return means for the second actuating piston of the second clutch;

advantageously, the balancing cap may comprise an annular plate of the helical spring supporting the elastic return means of the first piston, which is located on the outer periphery of the balancing cap;

the wet double clutch can be controlled so as to selectively couple the internal combustion engine and the rotary electric machine to the first and second driven shafts, the first and second disk supports being kinematically connectable to the internal combustion engine;

preferably, said portion of the second disk holder, the balancing cover and said portion of the first disk holder can be positioned radially below the rotary electric machine, so as to optimize the axial and radial compactness of the transfer line (in-line and off-line), regardless of the power source used;

the wet double clutch may comprise a drive cover kinematically connected with the rotary electric machine, the drive cover being attached to the periphery of the flange of the central hub, blocking the radial end of the at least one oil supply channel. The advantage of this wet double clutch is that the radial footprint is reduced, as the drive cover is positioned on the periphery of the flange, while facilitating the transport of fluid within the wet clutch. The sealing of the oil supply channel is achieved by covering the opening with a member initially arranged to transmit torque. Thus reducing the number of parts required to manufacture the dual wet clutch.

Preferably, the central hub may comprise a first annular chamber located to one side of the flange and arranged to receive the actuator piston of the first clutch and a second annular chamber arranged to receive the actuator piston of the second clutch, the at least one oil supply passage being present in one of the annular chambers of the clutches. Due to this construction, the annular chamber forms a control chamber of the clutch. The control chambers are concentric and radially positioned in the same plane, facilitating installation of the wet clutch in the torque transmission line;

advantageously, the oil supply channels for the first and second chambers may be arranged in the same plane through the flange. This facilitates its integration into the wet double clutch and its production. Therefore, the axial footprint of such wet dual clutches is reduced;

the drive cap may comprise an inner cylindrical surface for supporting the actuator piston seal, the cylindrical surface portion forming the first annular chamber. The wet double clutch according to the invention has the advantage of reducing the manufacturing costs due to the use of the attached annular drive cover. This attached annular portion enables the annular cavity to be formed in part at a lower cost.

Another object of the present invention is a method for assembling a wet double clutch, which may have all or some of the above characteristics, comprising at least the following steps:

a) providing a first disk holder having a rotation axis X, a second disk holder and a balancing cover,

b) placing the balance cover so that it is axially supported on a portion of the first disk holder,

c) placing a portion of the second disk holder so that it is axially supported on the balance cap,

d) the portions of the second disc holder and the first disc holder are fastened together end-to-end by welding, for example by laser welding.

According to the method, the step of assembling the three components is performed in a simple manner. In a single welding operation, the two disc holders are assembled end-to-end via their ends, so that the balancing cover can be fixedly positioned. This avoids, for example, the addition of another component or additional welding.

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

Drawings

The invention will be better understood and other objects, details, characteristics and advantages thereof will become more apparent from the following description of particular embodiments thereof, given by way of non-limiting illustration only, with reference to the accompanying drawings. In the drawings:

fig. 1 is an axial sectional view of a wet double clutch according to a first embodiment of the invention;

fig. 2 is another axial cross-sectional view of the wet double clutch according to the first embodiment of the invention;

fig. 3 is an axial sectional view of a wet double clutch according to a second embodiment of the present invention.

Detailed Description

By "vehicle" is meant a motor vehicle, including not only passenger cars, but also industrial vehicles, including in particular heavy goods vehicles, public transport vehicles and agricultural vehicles, and any means of transport capable of transporting living beings and/or objects from one location to another.

In the following description and claims, by way of non-limiting example and for the sake of easy understanding, the terms "front" or "rear" will be used with reference to a direction relative to an axial orientation determined by the main axis of rotation X of the transmission of the motor vehicle, and the terms "inner/inner" or "outer/outer" will be used with reference to the axis X and with reference to a radial orientation orthogonal to said axial orientation.

Unless otherwise stated, "axial" means "parallel to the axis of rotation X of the balance cover or the dual clutch", "radial" means "along a transverse axis intersecting the axis of rotation of the wet dual clutch", "angled" or "circumferentially" means "around the axis of rotation X of the wet dual clutch".

Here, the thickness is measured along the rotation axis X. Unless otherwise stated, the verbs "comprising", "having" or "including" must be interpreted broadly, i.e. without limitation.

Fig. 1 and 2 depict a first embodiment of a wet double clutch 1 for a vehicle transmission. The wet double clutch 1 is shown in a motor vehicle torque transmission line by means of a gearbox housing provided with two driven torque output shafts a1, a 2.

The wet double clutch 1 thus includes a first clutch E1 and a second clutch E2, each of multiple disc type, which are controlled to selectively couple the internal combustion engine and the rotary electric machine M to the first and second driven shafts. Torque from the internal combustion engine and the electric motor may then be transferred to the coaxial gearbox shafts a1, a2 upon closure of one or the other of the first clutch E1 and the second clutch E2. When the first clutch E1 is closed, the first driven shaft a1 rotates, and when the second clutch E2 is closed, the second driven shaft a2 rotates. The first clutch E1 and the second clutch E2 are positioned radially one above the other about the axis of rotation X.

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

In the illustrated example, the generally L-shaped input member 2 includes a radially oriented portion formed by the torque input web 3 and an axially oriented portion formed by the torque input hub 4. The web 3 and the hub 4 are rigidly connected to each other, preferably fastened together by welding. The torque input hub 4 is rotatably guided in a housing 101, the housing 101 being fixed relative to the torque transmission line. The torque input hub 4 is rotatably connected, for example by means of splines formed at the output of a damping device (for example a dual mass flywheel or the like), the output of which is connected, in particular through an engine flywheel, to a drive shaft formed by a crankshaft rotated by an internal combustion engine provided on the motor vehicle.

The two clutches E1, E2 include a first torque input disc carrier 10 and a second torque input disc carrier 120, which are kinematically connected to the internal combustion engine. The torque input web 3 is rotatably connected to a first torque input disc carrier 10, arranged to receive a multi-disc assembly of a first clutch E1. The rotational connection is here realized by welding, but it can also be realized by interlocking splines.

In the illustrated example, the first disc holder 10 includes an internal spline 10a that engages with the multi-disc assembly of the first clutch E1. The multi-plate assembly of the first clutch E1 includes a plate 11 rotatably connected to the first plate holder 10, and a friction plate 12 rotatably connected to the output plate holder 13.

The friction discs 12 are individually axially interposed between two successive plates 11. The output disc carrier 13 of the first clutch E1 is rotationally connected by meshing with the friction discs 12 and rotationally connected by a splined connection with the first driven shaft a 1. The output disc carrier 13 has an overall "L" shape with its radially inner end rigidly connected to a splined output hub.

The second disc carrier 20 is arranged to receive the multi-disc assembly of the second clutch E2. In the present case, the second disc carrier 20 is cylindrical and includes internal splines 20a which engage with the multi-disc assembly of the second clutch E2. The multi-plate assembly of the second clutch E2 includes a plate 21 and a friction plate 22, the plate 21 being rotatably connected to the second plate holder 20 attached to the first plate holder 10, the friction plate 22 being rotatably connected to the output plate holder 23. The output disc carrier 23 of the second clutch E2 is rotatably connected by meshing engagement with the friction discs 22 and is rotatably connected by a splined connection to the second driven shaft a 2. The output disc carrier 23 has an overall "L" shape with its radially inner end rigidly connected to a splined output hub.

The wet double clutch 1 is hydraulically controlled by a pressurized fluid (typically oil). In order to selectively control the state changes of the first clutch E1 and the second clutch E2, the control device of the wet dual clutch manages the supply of the pressurized oil in the separate control chambers. The control device is typically incorporated in the gearbox housing.

The control device is supported and connected to the central hub 50. As shown in fig. 1, the center hub 50 includes pressurized oil supply passages 54a and 54c so that the center hub 50 can supply oil to the first clutch E1 and the second clutch E2. As is well known, in operation of the wet clutch, a balance chamber 31, 41 is associated with each control chamber 32, 42. Typically, the balance chamber is positioned axially beside the annular chamber which serves as a control chamber.

In the illustrated example, the central oil supply hub 50 comprises:

a cylindrical portion 55 having an axis X,

a flange 53 extending radially from the cylindrical portion 55,

a first annular chamber 51, positioned at the side of the flange and designed to receive the actuating piston 14 of the first clutch E1,

a second annular cavity 52, located on the same side of the flange as the first annular cavity, and arranged to receive the actuator piston 24 of the second clutch E2,

oil supply channels 54a, 54b and 54c, passing through the cylindrical portion 55 and the flange 53 and entering the annular chamber, in particular the balancing chamber 31 of the first clutch E1.

An oil supply passage 54a machined in the central hub 50 is associated with the control chamber of the second clutch E2. The oil supply conduits 54a are made by drilling successive axial and radial conduits in the central hub 50. The conduits extend into each other and are arranged to supply pressurized fluid to a control chamber of the second clutch E2. An oil supply channel 54b is present in the second annular cavity 52 formed directly in the central hub 50.

The annular chambers 51, 52 of the first clutch E1 and of the second clutch E2 are oriented in the same direction, in this example towards the drive shaft, i.e. towards the internal combustion engine of the torque transmission line. The first cavity 51 and the second cavity 52 are radially nested one above the other. The first balance chamber 31 of the first clutch is positioned axially beside the first cavity 51. The second balance chamber 41 of the second clutch is positioned axially beside the second cavity 52. The multi-plate assembly of the second clutch E2 is positioned radially between the first and second chambers. Thus, the available space inside the wet double clutch can be utilized, thereby reducing the axial footprint.

The first clutch E1 is actuated by the first actuating piston 14, the movement of the piston 14 is controlled by the control chamber 32, and the balance chamber 31 is associated with the control chamber 32. The actuation piston 14 of the first clutch E1 is axially movable between a disengaged position and an engaged position, here from rear to front, corresponding to the open and closed states of the first clutch E1, respectively. The multi-plate assembly of the first clutch E1 is directly actuated by the first actuating piston 14. The movement of the first actuator piston 14 is controlled by a control chamber 32 delimited by a first cavity 51. Similarly, movement of the second actuator piston 24 is controlled by the control chamber 42 defined by the second chamber 52. Thus, the control chambers 32, 42 of the first clutch E1 and the second clutch E2, respectively, are positioned as close as possible to the central oil supply hub in order to reduce leakage within the wet dual clutch.

The second clutch E2 is actuated by the second actuator piston 24, the movement of the second actuator piston 24 is controlled by the control chamber 42, and the balance chamber 41 is associated with the control chamber 42. The actuator piston 24 of the second clutch E2 is axially movable between a disengaged position and an engaged position, here from rear to front, corresponding to the open and closed states of the second clutch E2, respectively. The multi-plate assembly of the second clutch E2 is directly actuated by the second actuating piston 24 by pressing a sheet metal plate.

The second actuator piston 24 is axially movable relative to the second annular cavity 52 of the central hub 50. Likewise, the free end of the second actuator piston 24 of the second clutch E2 supported on the multi-plate assembly is positioned radially between the first chamber 51 and the second chamber 52 oriented toward the drive shaft. The cylindrical portion 55 of the central hub extends axially in a direction away from the drive shaft. The balancing chambers 31, 41 are supplied with coolant.

The cylindrical portion includes oil supply passages 54a, 54b, and 54c of the first chamber 51, the second chamber 52, and the balance chambers 31 and 41. The coolant employs an oil supply passage 54b that is separate from the other oil supply passages 54a and 54 c. The oil supply passage 54b is also formed in the central oil supply hub 50. The oil supply passages 54a, 54b, and 54c are angularly distributed around the cylindrical portion 55. Preferably, the central portion 50 supports the first and second clutches together, for example on a cylindrical portion 55 or a flange 53. Each of the oil supply passages 54a, 54b, and 54c consists of generally radial and axial perforations oriented toward the control chambers of the first and second clutches E1, E2, but also toward the balance chambers 31, 32 of the first and second clutches E1, E2. The oil supply channels 54a, 54b, 54c of the first chamber 51, of the second chamber 52 and of the first balancing chamber 31 are angularly distributed around the rotation axis X and pass radially through the flange 53.

For example, the oil supply passage 54c, which is located axially at the rear end of the central hub 50, is associated with the control chamber 42 of the first clutch E1. The oil supply channel 54c is formed by drilling successive axial and radial conduits in the central hub 50. The conduits are in contact with each other and are arranged to supply pressurized fluid to the control chamber 32 of the first clutch E1. Fig. 1 shows an oil supply passage 54b machined in the central hub 50 and associated with the balance chamber of the first clutch E1. In this example, the oil supply passage 54b is common to the oil supply passage of the balance chamber 31 of the second clutch E2. The oil supply channel 54b is formed by drilling successive axial and radial conduits in the central hub 50.

The first balancing chamber 31 is partially delimited by the balancing cover 70 of the first clutch E1, so that a closed chamber is formed into which the passage 54b emerges. Thus, the first actuator piston 14 and the balance cover 70 of the first clutch E1 together form the balance chamber 31 of the first clutch. The balancing cap is particularly arranged to interact with the first actuation piston 14 by sliding. The balance cover 70 is positioned radially above the multi-plate assembly of the second clutch E2.

Preferably, the balance cap 70 is an annular or cylindrical member having a constant sheet metal thickness Ep. Balance cap 70 extends radially between diametrically opposed outer and inner peripheries 74, 75 thereof. The inner periphery 75 is positioned radially inward of the first disc holder 10, preferably at least partially below the multi-disc assembly of the first clutch E1. Thus, the inner periphery 75 is located radially below the first actuator piston 14 and radially above the second actuator piston 24. The outer periphery 74 is formed, for example, by bending the balance cap 70.

In the illustrated example, the balance cap 70 also includes a continuous annular or cylindrical skirt 76 that partially defines the balance chamber 31 of the first clutch E1. The skirt 76 of the balancing cover 70 extends 360 degrees around the axis X on both sides towards the first and second disc holders 10, 20. As a result, the skirt 76 partially connects the radially opposed outer and inner peripheries 74, 75 together.

In fig. 1 to 3, a portion of the balancing cover 70 is axially delimited between two opposite lateral support surfaces 71, 72. The lateral support face 71 faces the first disk holder 10. The lateral support surface 72 advantageously faces the second disk holder 20. The space between the opposing lateral support surfaces 71, 72 defines a thickness Ep axially.

The balance cover 70 defining the balance chamber 31 is notable in that it is axially retained by the first disk holder 10 and the second disk holder 20. The balancing cover 70 is axially supported on its lateral support face 71 on a portion 15 of the first disk holder 10. As a result, the support area 150 of the portion 15, referred to as the first support area of the first tray support 10, defines a usable support surface for receiving the balancing cover 70. Preferably, the support area 150 is the area "closest" to the balancing cover 70 and is oriented along the axis X towards the lateral support face 71. In fig. 1 to 3, the portion 15 receives a balancing cap 70 on its inner periphery 75. Thus, the inner periphery 75 is axially retained with respect to the first disk holder 10. As a variant not shown, the portion 15 can receive the periphery 74.

Furthermore, the balancing cap 70 is axially supported on its lateral support face 71 on a portion 25 of the second disk carrier 20. As a result, the support area 250 of the portion 25, referred to as the second support area of the second disc holder 20, defines a usable support surface for receiving the balancing cover 70. Preferably, the support region 250 is the region "closest" to the balancing cover 70 and is oriented along the axis X towards the lateral surface 72.

In the example illustrated, the portion 25 is a radially inner portion of the second disc holder 20 and is circumferentially continuous, for example annular, about the axis X. As a variant not shown, the portion 25 may comprise segments of material angularly distributed about the axis X

The support areas 150,250, which are separate from each other, each receive said respective lateral surface 71, 72 of the balancing cover 70. The support areas 150,250 may receive the same portion of the balancing cover 70, or conversely, different portions of the balancing cover, that is, portions that are positioned differently from one another.

As a variant not shown, the portion 25 may receive, for example, the inner periphery 75 and the portion 15 may receive another portion of the balancing cap 70, for example, the outer periphery 74.

In fig. 1 to 3, the balancing cover 70 is advantageously positioned axially between the first disk holder 10 and the second disk holder 20. As a result, axial support via the support regions 150,250 occurs on either side of the balancing cap 70. The portions 15, 25 are located on either side of the balancing cap 70, close to each other. More specifically, the support areas 150,250 receive the inner perimeter 75. Thus, the inner periphery 75 is commonly retained by the portions 15, 25, axially interposed (sandwiching the same portion of the balancing cap 70) between the portions 15, 25 via respective support areas 150,250 of the portions 15, 25.

In the step of assembling the two disc holders 10, 20, the portion 25 thus fixedly presses or positions the inner periphery 75 of the balancing cover 70 on the portion 15 along the axis X via the respective support areas 150, 250. Thus, the portion 25, the balancing cap 70 and the portion 15 are axially stacked on top of each other.

In the illustrated example, the support region 250 of the second disk holder 20, the balancing cover 70 and the support region 150 of the first disk holder 10 are positioned axially one after the other. In other words, a straight line D extending parallel to the axis X passes simultaneously through the support region 250, the inner periphery 75 of the lid and the support region 150 in succession.

In fig. 1-3, the opposing lateral surfaces 71, 72 axially define an inner periphery 75. In other words, the first support surface 71 and the second support surface 72 are located at the same end of the balance cover 70. The radially inner edge 73 of the balancing cover connects the two axially opposite support surfaces 71, 72. Preferably, the support region 150 extends radially above the internal spline 20 a.

The first and second disk supports 10, 20 are rigidly secured together end-to-end and connected to each other at their respective portions 15, 20. In other words, the portions 15, 25 are rigidly connected together, for example by welding 100, as shown in fig. 1 and 2. Advantageously, the weld seam 100 is discontinuous about the rotation axis X, so as to form a plurality of weld beads angularly distributed about the axis X.

In the first embodiment, the weld 100 is a laser weld. Portion 25 is supported by portion 15. In fig. 1 and 2, the balancing cap is (indirectly) held by said weld seam 100. The parts 15, 25 may also be assembled by any other possible fastening means, for example by form-fitting, such as a boss or spline connection, or by other fastening or assembling means.

Advantageously, the portions 15, 25 interact with each other. As a variant not shown, the portion 15 of the first disc holder may also comprise a series of angularly distributed pressing bosses, on which the balancing cover is centered, and a series of support areas formed on each of the bosses.

In this case, the bosses may be discontinuous and distributed angularly about the axis X, in a uniform distribution. For this purpose, the balancing cover can be held differently by form fitting or nesting. The balancing cover may have a shape complementary to the shape of the annular rim, for example a smooth or toothed profile, or an opening in the balancing cover adapted to the shape of and to receive the profile of the boss of the first disk holder, in order to improve the retention of said balancing cover. The portions 25 of the second disc holder may be attached to the series of pressed bosses, for example fastened together by welds 100.

Advantageously, the second disc holder 20 further comprises a collar 251, which is axially located at the end of the internal spline 20 a. The collar 251 is formed integrally with the spline 20 a. Preferably, the collar 251 is continuous about the axis X. In fig. 1-3, the collar 251 extends inwardly from the radially inner end of the spline 20a toward the portion 15 or axis X. As a variant not shown, the collar 251 may extend radially outwards, for example towards the internal splines of the first disc holder 10.

The collar 251 is supported on the balance cap 70 in the support region 250 of the second disk holder. In other words, the portion 25 partially forms said collar 251. Preferably, the collar 251 and the inner periphery 75 of the balance cap 70 are of complementary dimensions. The support area 250 of the second disc holder 25 may be created by machining or pressing the collar 251. Preferably, the collar 251 is rigidly connected to the portion 15, preferably by welding at the ends of the collar. In the illustrated example, the weld 100 is formed partially on a radially inner edge or end of the collar 251.

In the first embodiment, the first disk holder 10 is a subassembly of assembly components. In addition to the internal splines 10a (multi-plate assembly supporting the first clutch E1), the first plate carrier 10 also includes the central hub 50. As a result, the portion 15 is formed by the central hub 50 of the first disk holder 10. Portion 15 is formed integrally with flange 53. Here, portion 15 is circumferentially continuous about axis X

In fig. 1 and 2, the internal splines 10a and central hub 50 are rigidly connected for common rotation by a drive cap 80. Thus, the assembled first disc holder 10 is composed of the spline 10a, the central hub 50 and the drive cover 80, thereby supporting the two clutches E1, E2 together.

A drive cap 80 is attached to the outer periphery of the flange 53 of the central hub 50. The function of the central hub 50 is to transmit torque within the wet double clutch 1. To this end, the drive cap 80 is rigidly connected to the central hub 50 for rotation therewith, in this case by press-fitting over the flange 53. As a variant not shown, the drive cap 80 can be welded to the flange of the central hub.

The drive cover 80 includes external teeth kinematically connected with the rotary motor M, the teeth being integrally formed with or attached to the drive cover. The external teeth have a helical profile, the shape of which is complementary to that of the pinion of the rotary electric machine M. Alternatively, the teeth may have a straight profile, the shape of which is complementary to the chain or belt used to connect the rotating electrical machine M.

As a variant not shown, the drive cap 80 may comprise a ring gear axially offset with respect to the flange 53 of the central hub 50. This ring gear is still kinematically connected to the rotary motor M so as to rotate with it about an axis parallel to the rotation axis X. In such a variation, the ring gear may be attached to the drive cap. The ring gear is therefore axially offset relative to the first clutch E1 and the second clutch E2, so that the radial compactness of the wet double clutch can be further improved.

In particular, the drive cap 80 comprises an inner cylindrical surface 81 for supporting the seal of the first actuating piston 14 of the first clutch E1, the cylindrical surface 81 partially forming the first annular chamber 51. The oil supply channel 54c emerges in the first annular chamber 51, this first annular chamber 51 being formed in part by the axial extension directly from the flange 53 and in part by the drive cap 80. The central hub 50 is adapted to transfer torque from two separate sources, i.e., combustion and electrical power.

As can be understood from fig. 1 and 2, all the oil supply passages 54a, 54b, and 54c are arranged in the same plane P perpendicular to the axis X passing through the flange 53. The oil supply channels 54a, 54b and 54c emerge radially on the outer periphery of the flange 53 and are closed off from the inner cylindrical surface 81 by the inner bore 82 of the drive cap. The drive cap 80 surrounds the outer periphery of the flange 53. In another possible case, the oil supply channel may be closed by an inner cylindrical surface of the drive cap.

As a variant not shown, to facilitate the production of the central hub 50, the annular member can be attached to the flange 53 of the central hub and comprise at least one inner or outer cylindrical surface for supporting the seal of one of the actuating pistons of the first clutch E1 or of the second clutch E2. The attached annular portion may thus partially form an annular cavity of one of the first and second clutches. The attached annular portion may be secured to the flange of the central hub by welding, for example by transparent laser welding.

Preferably, portion 15 also comprises an annular rim 17, which extends axially towards portion 25. The annular rim 17 receives the portion 25. As a result, the collar 251 surrounds the annular rim 17 of the first disk holder 10 to center the second disk holder 20 on the annular rim 17. The annular rim 17 is preferably spaced from the support region 150. In fig. 1 to 3, the annular rim 17 is situated radially below the support region 150. Preferably, the annular rim 17 extends at an angle of 360 ° about the axis X.

As a variant not shown, the annular rim 17 may be positioned radially above the internal splines of the second disc carrier and/or above the support area 150.

Preferably, the annular rim 17 is integral with the portion 15. The annular rim 17 is thus obtained by forging and machining the portion 15, in particular from the flange 53. As a variant not shown, the annular rim 17 can be attached to the first disk holder 10, for example fastened by welding.

Advantageously, the annular rim 17 supports the balancing cap 70, in particular on said radially inner edge 73, so as to center the balancing cap 70 on the annular rim 17. In fig. 1 to 3, the free space formed between the annular rim and the rest of the portion 15 makes it possible to receive and retain the end of the balancing cap 70. The annular rim 17 is thus positioned radially below the internal spline 20 a.

To ensure optimal operation, the balancing chamber 31 is sealed by a seal, comprising a seal 90 of the balancing cap 70, which rubs on the cylindrical portion of the first piston 14. The skirt 76 of the balance cap 70 includes a seal 90, here overmolded, on its outer periphery 74.

The wet dual clutch further comprises a resilient return element 40 of the first actuating piston 14, which is supported on the balancing cover 70 or is formed together with the balancing cover 70. The function of the elastic return element 40 is to automatically return the first actuating piston 14 to the disengaged position, corresponding to the open state of the clutch. The elastic restoring element 40 is, for example, an elastic washer or an elastic restoring means. Advantageously, the balancing cover 70 supports or partially forms the elastic return element 40.

In the illustrated example, the balance cap 70 includes an annular plate that partially forms the resilient return means of the first actuation piston 14, which is located on the outer periphery 74 of the balance cap 70, as shown in fig. 1 to 3.

The elastic return element 40 comprises a series of helical springs supported on the first actuation piston 14 by a first annular support plate 63, axially interposed between the front wall of the first actuation piston 14 and the annular surface of the balancing chamber. Thus, the first support plate 63 supports the series of springs and pushes back the first piston 14 by applying an axial compression force. Thus, the first axial reset force opposes motion.

Instead, the annular plate of the balancing cap 70 supports the coil spring of the first piston 14, here by the second plate 64, the second plate 64 itself being supported on the balancing cap 70 and being pressed by the coil spring towards the outer periphery 74. In fig. 1 to 3, a plurality of helical springs are thus positioned axially between the first actuating piston 14 and the annular plate of the balancing cover 70. As a variant not shown, the annular plate of the balancing cover 70 and the second plate 64 may form a single part, in particular comprising a guiding stud able to receive said helical spring.

A method for assembling the wet double clutch as shown in the first embodiment in fig. 1 and 2 will now be described. The assembly comprises, among other things, the steps of:

according to a first step, a first disk holder 10 having a rotation axis X, a second disk holder 20 and a balancing cover 70 are provided;

according to a second step, the balancing cover 70 is placed so that it is axially supported on a portion 15 of the first disk holder 10;

according to a third step, a portion 25 of the second disc holder 20 is placed so that it is axially supported on the balancing cover 70;

according to a fourth step, the second disc holder 20 and the first disc holder 10 are fastened together end-to-end by welding 100, for example laser welding.

The advantage of this method is that the clutch cover is fixedly mounted only in a single welding operation between the first and second disc holders. According to a third step, the portion 15 is preferably positioned axially facing the portion 25, so as to bring the applied axial support closer together, improving the retention of the balancing cover 70. Furthermore, the portion 25 may advantageously have a complementary shape to a portion of the cover, to provide improved fixed retention of said cover 70, for example by form-fitting or nesting.

Fig. 3 shows a second embodiment of the invention, which is substantially similar to the first embodiment, except that the parts 15, 25 are assembled by clip or snap fastening, without any additional welding. The portion 25 of the second disc holder 20 is fastened to said annular rim 17 by means of a clip or resilient retaining ring 60. As a result, the balancing cap is (indirectly) held by said elastic ring 60.

In the second embodiment, the portion 15 of the first disc holder 10 comprises a recess 255 adapted to receive the elastic ring 60. According to the first and fourth steps of the method for assembling the wet dual clutch, an elastic ring 60 is additionally provided, which is inserted into said groove 255 in the portion 15 during the fourth step. The elastic ring 60 received in the groove 255 makes it possible to hold and rotatably connect the second disk holder 20 to the first disk holder 10 without any welding. The elastic ring 60 is, for example, a belleville washer centered on the axis X.

As a result, the elastic ring 60 axially retains the portion 25, the portion 25 being intended to be rotated by the portion 15. Likewise, the annular rim 17 is formed integrally with the portion 15. Likewise, the portions 15, 25 interact with each other. The portions 25 of the second disc holder 20 are rotated by the bosses of the portion 15, angularly distributed about the axis X, for example so as to be uniformly distributed. The portion 25 is axially retained by an elastic ring 60.

In the second embodiment, the first disk holder 10 further includes a cylindrical web 151 that extends radially inward relative to the axis X from the internal spline 10a (the multi-disk assembly that supports the first clutch E1). The portion 15 is formed by a central hub 151 of the first disk holder 10. As a result, the balance cap 70 is supported on the web 151 on its inner periphery 75. The web 151 also includes an annular rim 17 to center the balance cap 70, and a support portion 25 rigidly connects the first and second disk supports 10, 20.

In fig. 3, the first disk holder 10 is one piece and the web 151 at least partially includes the flange 53. The web 151 and the remainder of the central hub 50 may be secured together by welding, for example by a weld bead. The web 151 is preferably produced by forging.

To ensure optimal centering, the collar 251 and skirt 76 of the balancing cap 70 have complementary shapes. In the second embodiment, the skirt 76 is shaped to interact with a portion of the collar 251 by a form fit. In fig. 3, the skirt 76 is received and centered on the collar 251, more specifically on an edge or chamfer of the collar 251, spaced from the portion 25. This edge or chamfer is shown as pressed or arched and it connects the internal spline 20a to the portion 25 of the second disc holder 20.

As can be understood from the above, the present invention proposes a wet double clutch in which the clutches are concentric and radially positioned in the same plane. The axial occupation of the wet double clutch in the torque transmission line is reduced. Such a wet double clutch comprises a central oil supply hub, wherein the network of oil supply channels is simpler in design and shorter in manufacturing time.

The invention is in no way limited to the arrangements and constructions described and illustrated herein, but extends to any equivalent arrangement or construction and any technically operable combination of such arrangements. In particular, without prejudice to the invention, it is possible to modify the shape of the central oil supply hub, as long as these components finally perform the same functions as those described in the present document.

The wet dual clutch according to the invention can be associated with a K0 disconnect clutch, in which case the K0 disconnect clutch will be located upstream of the torque input element 2. The KO disconnect clutch will make it possible to disconnect the internal combustion engine from the rest of the drive line.

For example, the wet dual clutch according to the invention may form part of a triple clutch or hybrid clutch, suitable for automatic, semiautomatic, hybrid and/or electric transmissions of motor vehicles.

In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

Claims (14)

1. A dual wet clutch (1) for torque transmission comprising:

a first clutch (E1) and a second clutch (E2) each of the multiple-disc type, the first clutch (E1) and the second clutch (E2) being positioned one above the other in the radial direction about the rotation axis (X),

the first clutch (E1) comprising a first disc support (10) adapted to support a multi-disc assembly of the first clutch (E1), the first clutch being actuated by a first actuating piston (14), the movement of which is controlled by a control chamber (32), a balancing chamber (31) being associated with the control chamber (32),

a balance cover (70) defining a balance chamber (31) of the first clutch (E1),

the second clutch (E2) comprising a second disc carrier (20) adapted to support a multi-disc assembly of the second clutch (E2), the second disc carrier (20) being rigidly connected to the first disc carrier (10) for rotation therewith,

characterized in that the balancing cover (70) is axially retained between the first disk holder (10) and the second disk holder (20).

2. The dual wet clutch (1) according to claim 1, wherein the balancing cover (70) is axially supported on a portion (15) of the first disc holder (10) and on a portion (25) of the second disc holder (20), axial support occurring on either side of the balancing cover (70) and defining a support area (150, 250).

3. Double wet clutch (1) according to claim 2, wherein the support area (250) of the second disc carrier (20), the balancing cover (70) and the support area (150) of the first disc carrier (10) are positioned axially one after the other.

4. Double wet clutch (1) according to one of claims 2 to 3, wherein the portion (15) of the first disc holder (10) comprises an annular rim (17) and the support area (150), the balance cap (70) being centered on the annular rim (17).

5. Double wet clutch (1) according to any one of claims 2 to 3, wherein the portion (15) of the first disc holder (10) comprises a series of pressed bosses distributed angularly, on which the balancing cover (70) is centered, and a series of support areas (150) formed on each of the bosses.

6. Double wet clutch (1) according to claim 4 or 5, wherein the portion (25) of the second disc carrier (20) is attached to the annular rim (17) or the series of pressed bosses, fastened together for example by a weld seam (100).

7. Double wet clutch (1) according to claim 6, wherein the portion (25) of the second disc holder (20) is fastened to the annular rim (17) or the series of pressed bosses by welding, the weld seam (100) being discontinuous about the rotation axis X, for example consisting of a plurality of weld beads angularly distributed about the axis X.

8. Double wet clutch (1) according to one of claims 2 to 7, wherein a cylindrical second disc carrier (20) comprises internal splines (20a) supporting a multi-disc assembly of the second clutch (E2) and a collar (251) at the end of a spline (20a), a portion (25) of the second disc carrier (20) forming in part the collar (251), the collar (251) being supported on the balance cap (70) in a support region (250).

9. Double wet clutch (1) according to one of the claims 2 to 8, wherein the balancing cover (70) comprises a first bearing surface (71) oriented along the axis X towards the first disc holder (10) and a second bearing surface (72) oriented along the axis X towards the second disc holder (20), the first bearing surface (71) and the second bearing surface (72) being located on an inner circumference (75) of the balancing cover (70).

10. Double wet clutch (1) according to any one of claims 2 to 9, wherein a first disc holder (10) of cylindrical shape comprises internal splines (10a) supporting a multi-disc assembly of the first clutch (E1) and a web extending radially inwards with respect to an axis (X), the portion (15) of the first disc holder (10) being formed by the web (151), and the balancing cover (70) being supported on the web (151) of the first disc holder (10).

11. Double wet clutch (1) according to any one of claims 2 to 9, wherein the first disc carrier (10) is a subassembly comprising a central hub (50) and internal splines (10a) of a multi-disc assembly supporting the first clutch (E1), the internal splines (10a) and the central hub (50) being rigidly connected for common rotation, a portion (15) of the first disc carrier (10) being formed by the central hub (50).

12. Double wet clutch (1) according to claim 11, wherein the central hub (50) comprises a flange (53) extending radially with respect to the axis (X), the balancing cover (70) being supported on the flange (53) in the portion (15), the central hub (50) comprising an oil supply channel (54a, 54b, 54c) passing through the portion (15) and the flange (53) and emerging into the balancing chamber (31) of the first clutch (E1).

13. Double wet clutch (1) according to any of claims 1 to 11, wherein the balance cap (70) comprises a skirt (76) adapted to interact with the collar (251) in order to center the skirt (76) on the second disc holder (20).

14. Method for assembling a wet double clutch, comprising at least the following steps:

a) providing a first disk holder (10) having a rotation axis (X), a second disk holder (20) and a balancing cover (70),

b) placing the balancing cover (70) so that it is axially supported on a portion (15) of the first disk holder (10),

c) placing a portion (25) of the second disc holder (20) such that it is axially supported on the balancing cover (70),

d) the second disc holder (20) and the first disc holder (10) are fastened together end-to-end by a weld, such as a laser weld (100).

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