DE102009006422B4 - Dual clutch assembly for motor vehicles and method of operation therefor - Google Patents

Abstract

A dual clutch arrangement (16) for a motor vehicle (11), comprising a housing (62), a first dry friction clutch (42) and a second dry friction clutch (44), the friction clutches (42, 44) each having an input member (46, 48) which can be connected to a drive shaft (28), wherein the friction clutches (42, 44) have a first and a second output member (50, 82, 52, 84) which are connected to a first and a second transmission input shaft (38, 40), with a first actuator (68) for actuating the first friction clutch (42) and with a second actuator (70) for actuating the second friction clutch (44), wherein the actuators (68, 70) on a housing-fixed hub ( 58) are arranged and the associated friction clutch (42, 44) each directly via a thrust bearing (74) actuate, characterized in that on the hub (58) between the output members (50, 82, 52, 84) arranged central plate (54 ) is mounted radially, wherein the first Ausgangsg Song (50, 82) between the first input member (46) and the central plate ...

Description

The The present invention relates to a dual-clutch arrangement for a motor vehicle, with a housing, a first dry friction clutch and a second dry one Friction clutch, wherein the friction clutches each have an input member have, which is connectable to a drive shaft, wherein the Friction clutches have a first and a second output member, connectable to first and second transmission input shafts are, and with a first and a second actuator for actuating the first and the second friction clutch, wherein the actuators on a housing-fixed hub are arranged and the associated friction clutch in each case via a Actuate thrust bearing directly.

The publication DE 10 2006 010 113 B4 shows, for example, a dual clutch assembly according to the preamble of the invention.

such Dual clutch arrangements are used in dual-clutch transmissions for motor vehicles used. Such dual-clutch transmission have in addition to the dual clutch arrangement two partial transmissions on. The partial transmissions are usually in countershaft design executed. One of the partial transmission is assigned to the even gears, the other partial transmissions the odd gears.

By overlapping activity The two friction clutches can be a gear change without interruption of traction carried out become. This type of dual-clutch transmissions is suitable for every type of motor vehicles, in particular for passenger cars.

In the dual clutch arrangements usually fluidly operated (wet) friction clutches are used, for example. Wet-running multi-plate clutches. Examples of this can be found in the publications DE 101 46 606 A1 and DE 10 2005 063 248 A1 ,

Wet-running Although multi-plate clutches can indeed transmit relatively high moments. Because the resulting in the slip operation due to the frictional Heat can by the fluid used (cooling oil) comparatively be transported well. Wet-running multi-plate clutches have but generally a slightly lower efficiency than conventional ones Dry clutches, as used in manual transmissions for many Years, in particular due to the higher drag losses.

Although it is generally desirable, such dry friction clutches also in dual clutch arrangements of the type described above use, this application is problematic in some ways. For one thing Dry friction clutches a relatively large amount of space. In addition, are dry Friction clutches normally closed in the unactuated state and will be over a relatively complex Lever mechanism open (Disengaged). Furthermore, such dry friction clutches, if automated actuated be generally regulated so that the clutch travel the relevant Controlled variable is.

In front In this context, it is the object of the invention to provide an improved Double clutch arrangement for a motor vehicle and a method for operating a dry friction clutch specify.

These Task is a double clutch assembly for a motor vehicle solved, with a housing, a first dry friction clutch and a second dry one Friction clutch, wherein the friction clutches each have an input member have, which is connectable to a drive shaft, wherein the Friction clutches have a first and a second output member, connectable to first and second transmission input shafts are, with a first actuator for actuating the first friction clutch and with a second actuator for actuating the second friction clutch, wherein the actuators are arranged on a housing fixed hub and directly actuate the associated friction clutch via a thrust bearing, wherein the first output member between the first input member and the Central plate and the second output member between the second Input member and the central plate is clamped to the associated friction clutch close.

The The above object is further solved by a method for actuating a dry friction clutch, in particular a dual-clutch transmission, being a housing solid Actuator operated the friction clutch directly via a thrust bearing, wherein the Actuator over a controller is controlled whose controlled variable applied by the actuator Force is, and the friction clutch is an output member and an input member and the output member between the input member and a Central plate is clamped.

By direct operation the dry friction clutches over Thrust bearing is possible, on the one hand, complex To avoid lever constructions. Moreover, in such a activity also possible, to regulate the dry friction clutch so that the relevant Controlled variable from the force applied to the actuator. With such an actuation method especially the overlapping operations of two friction clutches of a dual-clutch transmission simpler or realize more efficiently.

The Central plate can interact with the moving parts of the friction clutches move along and can support serve by operating forces. Provided the friction clutches in the longitudinal direction are arranged one behind the other, the plate is preferably as a central plate formed between the output members of the friction clutches is arranged.

The used in the prior art lever mechanisms for operating dry Friction clutches have too much inherent elasticity and hysteresis properties, so that a force control is generally unthinkable.

The fixed to the housing Hub can serve any kind of actuator and any type of feed to realize energy to the actuator.

Further Overall, a very compact structure can be realized.

Under a direct operation the friction clutch over a thrust bearing should therefore be understood in the present case that the friction clutch without force-displacement-converter (like a lever mechanism) actuated becomes.

The Use of a housing-fixed Hub for the storage of actuators also allows a fluidic activity the friction clutches. Because on a housing-fixed hub can in contrast to rotary rotary joints (The mechanical seals have) a substantially complete seal across from the clutch space can be achieved, for the operation of dry friction clutches necessary is.

There A complex force-displacement converter is not needed, is not a wear adjustment necessary or less expensive especially when the operation the respective dry friction clutch is force-controlled.

So far in this case of the controlled variable "force" the speech is understood that this term is synonymous with this proportional sizes, like For example, the hydraulic pressure in a hydraulic actuator.

The Task is thus completely solved.

According to one preferred embodiment the hub on the drive side of the dual clutch assembly with the housing connected.

A such motor-side support allows a pre-assembly of the complete dual-clutch arrangement. These preassembled dual-clutch arrangement must for mounting the dual-clutch transmission only over pushed the transmission input shafts and in the area of the motor flange be screwed.

According to one another preferred embodiment is the first output member on the transmission side of the dual clutch assembly via a first Radial bearing on the housing stored.

According to one another preferred embodiment is the second output member on the transmission side of the dual clutch assembly via a second Radial bearing mounted on the first output member.

hereby axial space is saved. Moreover, it is not necessary this Components on one of the transmission input shafts (such as a hollow shaft of the gearbox).

Provided the output links rigid with the transmission input shafts of the partial transmission are connected, these radial bearings also serve to support the transmission input shafts. A separate shaft bearing in the coupling wall can be omitted. Further the axial space can be reduced.

All in all it is further preferred if the thrust bearings each for transmission of axial forces of at least 4,000 Newton, in particular at least 5,000 Newton are designed.

By Use of such dimensioned thrust bearing is an application the dual clutch assembly in motor vehicles in the usual Service areas possible.

All in all It is also advantageous if the thrust bearings each lubricated are.

at this embodiment Consequently, it is not necessary for the thrust bearings during the Operate permanently supplying a fluid such as a cooling oil. Accordingly, are suitable These thrust bearings especially in combination with dry friction clutches.

Further it is advantageous if at least one of the thrust bearing as a double row Thrust bearing is formed.

With such a thrust bearing can be space-optimized, the necessary axial forces transferred to the respective friction clutch.

In general, a double-row thrust bearing is understood here to mean any type of reinforced thrust bearing, ie, for example, so-called four-point bearing or bearing with other rolling elements as balls. It is crucial that in this case a relatively large axial force is transferable. This is also important in dry couplings because only two Friction surfaces are available to transmit the necessary moments.

Further it is advantageous if the hub has at least one hydraulic fluid channel has no function.

A such design allows it that the hub can also be used with other dual-clutch transmissions is, for example, include wet-running multi-plate clutches. At this Application, the hydraulic fluid channel then eg. For cooling / lubrication the wet dual clutch arrangement can be used.

Further It is generally advantageous if the friction clutches in the longitudinal direction arranged one behind the other and with respect to a transverse to the longitudinal direction Level are arranged substantially mirror-symmetrically.

hereby For example, the dual clutch arrangement can be in particular in the radial direction be realized with a comparatively small space.

Further It is altogether advantageous if the dual clutch arrangement a control unit for driving the actuators, wherein the control unit is designed to force-control the friction clutches to press.

in this connection can for the Operation of the dual clutch designed much simpler control strategies be, especially at the intersecting activity the friction clutches. Furthermore, a wear adjustment can be omitted or be simplified.

The Actuators are in accordance with a another overall preferred embodiment as a hydraulic Actuators trained.

These embodiment is particularly suitable, although the transmission part of the dual clutch transmission is controlled by hydraulic actuators. In addition, are suitable hydraulic actuators particularly well for the realization of a force control, as it should preferably be realized.

Further it is advantageous if at least one actuator housing element welded to the hub. Hereby, the number of seals can be reduced and the Place of welding can when setting the clearance be set the respective friction clutch.

The weld together an actuator housing element with the hub leads Furthermore, lower production costs in an automatic assembly and to a lower dispersion of the set clearance. Furthermore, the axial space can be reduced.

All in all it is also advantageous if an output member of one of Friction clutches connected to a rotor of an electric motor is disposed coaxially around the dual clutch assembly around is.

at This configuration, the dual clutch assembly for implementation a hybrid powertrain, either as a full hybrid or as a so-called "mild hybrid". Further can in a determination of the rotor on the outer circumference of the radially outer output member a high inertia will be realized.

It it is understood that the above and the following yet to be explained features not only in the specified combination, but also in other combinations or alone, without to leave the scope of the present invention.

embodiments The invention are illustrated in the drawings and in the following description explained. Show it:

1 a schematic representation of a first embodiment of a drive train with a dual clutch assembly according to the invention

2 a schematic longitudinal sectional view through a further embodiment of a dual clutch assembly according to the invention;

3 a detailed view of another embodiment of a dual clutch assembly according to the invention; and

4 a schematic longitudinal sectional view through a further embodiment of a dual clutch assembly according to the invention.

In 1 is a drive train of a schematically indicated motor vehicle 11 generally with 10 designated. The car 11 can be, for example, a passenger car.

The powertrain 10 includes a drive motor 12 , such as an internal combustion engine or a hybrid drive unit, and a dual-clutch transmission 14 ,

The dual-clutch transmission 14 on the one hand includes a dual clutch arrangement 16 and a gearbox 18 , which is a first partial transmission 20 and a second partial transmission 22 having.

The two partial transmissions 20 . 22 have a common output shaft 24 on, for example, with an axle drive a driven axle of the motor vehicle 11 is connectable. Furthermore, in 1 schematically a countershaft 26 of the transmission 18 shown to indicate that it is the transmissions 20 . 22 Generally geared in helical gear in countershaft design. One partial transmission is assigned the even gear stages, the other partial transmission the odd gear stages.

The drive motor 12 has a drive shaft 28 on that with the input of the dual clutch assembly 16 connected in the present case via a crankshaft pulley 32 , the damping agents 34 (such as a dual mass flywheel) may include. The dual clutch arrangement 16 has an input shaft 36 on that with an output member of the damping means 34 is connected and in a longitudinal direction 13 , substantially coaxial with the drive shaft 28 extends. The dual clutch arrangement 16 further includes a first output shaft 38 connected to the input of the first sub-transmission 20 is connected, and a second output shaft 40 connected to the input of the second sub-transmission 22 connected is. The second output shaft 40 is formed as an inner shaft and concentric with the input shaft 36 aligned. The first output shaft 38 is as a hollow shaft around the second output shaft 40 trained around.

The general operation of such a dual-clutch transmission 14 is well known and will not be discussed in detail herein. One of the key features of such dual-clutch transmissions, however, is that gear changes can be performed substantially without Zugkrafteinbruch by the drive power from the drive motor 12 by overlapping operation of the dual clutch assembly 16 is transferred from one sub-transmission to the other sub-transmission.

The dual clutch arrangement 16 has a first friction clutch 42 and a second friction clutch 44 on. The friction clutches 42 . 44 are designed as dry friction clutches, which need for operation no fluid supply in the form of a cooling fluid or the like.

The first friction clutch 42 has a first input member 46 on, and the second friction clutch 44 has a second input member 48 on. In a corresponding manner, the first friction clutch 42 a first output member 50 on, with the first output shaft 38 is connected, and the second friction clutch 44 has a second output member 52 on that with the second output shaft 40 connected is. Between the output links 50 . 52 is a central plate 54 arranged, which have a plate radial bearing 56 on a hub fixed to the housing 58 is rotatably mounted, which is designed as a hollow hub. The hub 58 Coaxially extends around the input shaft 36 around and is on the drive side (ie on the to the drive motor 12 facing side) via a radially extending support plate 60 with the housing 62 the dual clutch arrangement 16 rigidly connected.

In the support plate 60 are at least two fluid channels 64 present, with corresponding fluid channels 66 in the hub 58 are connected. The fluid channels 64 . 66 serve for fluid supply of a first actuator 68 and a second actuator 70 ,

The first actuator 68 serves to actuate the first friction clutch 42 , The second actuator 70 serves to actuate the second friction clutch 44 ,

The actuators 68 . 70 are right at the hub 58 arranged, on opposite sides of the plate radial bearing 56 , More precisely, the actuators are 68 . 70 arranged substantially mirror-symmetrically with respect to a plane perpendicular to the longitudinal direction 13 and through the central plate 54 passes through.

Each of the actuators 68 . 70 has a piston housing 72 up, rigid with the hub 58 is connected, for example. Via a weld 73 , Alternatively, the attachment can also be made via an axial circlip.

Each of the actuators 68 . 70 also includes a thrust bearing 74 , between a fluid-filled cylinder space of the piston housing 72 and a piston member 76 is arranged. The thrust bearing 74 can be the piston of the respective actuator 68 . 70 form.

The piston element 76 is with the first input member 46 connected. If the cylinder space of the actuator 68 is filled with fluid, the thrust bearing 74 longitudinal 13 offset, causing the piston element 76 longitudinal 13 is offset. As a result, the piston element exercises 76 directly an axial force 77 on the first input member 46 to close the associated friction clutch. This z. B. the first output member 50 between the first input member 46 and the central plate 54 clamped to this way the first input member 46 and the first output member 50 to connect in the direction of rotation.

Unless for the first actuator 68 hydraulic pressure is no longer available, opens the first friction clutch 42 , by means of a return spring 78 between the central plate 54 and the piston element 76 engages and is designed to the piston element 76 to press in an open position.

To the above description, it should be noted that the above-mentioned reference numerals in FIG 1 for the sake of clarity, only for the first actuator 68 are registered. The second actuator 70 can be operated in the same way, with its axial force acting on the second input member 48 acts exactly opposite to that of the first actuator 68 applied axial force 77 ,

It should also be noted that the actuators 68 . 70 each have a fixed part, the housing fixed to the hub 58 is connected (piston housing 72 ), Furthermore, the actuators have 68 . 70 in each case an axially displaceable piston element which has an axial force 77 on the input member 46 respectively. 48 exerts and thus in the circumferential direction with a rotation of the input shaft 36 can turn. The thrust bearing 74 thus has a circumferentially not co-rotating bearing ring, which in the manner of a piston in the piston housing 72 is guided axially. Furthermore, the thrust bearing 74 in each case a further bearing ring which is rigid with the piston element 76 is connected and is rotatable in the circumferential direction with respect to the aforementioned bearing ring. It is understood that in the thrust bearing 74 each suitable rolling elements may be present, such as, balls, rollers, etc.

The plate radial bearing 56 serves for a pivotal mounting of the central plate 54 at the hub 58 , On the other hand is the plate radial bearing 56 axially on the hub 58 fixes and holds the support plate 60 in an axial central position between the output members 50 . 52 ,

The input links 46 . 48 the friction clutches 42 . 44 are via a drive basket 80 with the input shaft 36 connected. The drive basket 80 extends from an axial end of the input shaft 36 , opposite the hub 58 preferably protrudes in the axial direction, in the radial direction to the outside. Furthermore, the drive basket 80 an axially extending portion extending from the radial portion in the axial direction back toward the drive motor 12 extends and with the two input members 46 . 48 connected is.

The first output member 50 the first friction clutch 42 is via a first output cage 82 with the first output shaft 38 connected. The first output cage 82 has an axially extending portion extending from the first output member 50 in the axial direction to the transmission 18 extends. Furthermore, the first output cage 82 a radial portion extending radially inwardly toward the first output shaft 38 extends. Furthermore, this radial section has a step section, by means of which the first output cage 82 over a first radial bearing 88 on the housing 62 is rotatably mounted.

The second output member 52 is via a second output cage 84 with the second output shaft 40 connected. The second output cage 84 extends radially within the first output cage 82 and is shaped like this. The radial sections of the two output cages 82 . 84 extend in the radial direction parallel to a housing wall 86 , the example. The interior of the dual clutch assembly 16 from the interior of the transmission 18 separates. The radial section of the second output cage 84 is also a second radial bearing 90 on the first output cage 82 rotatably mounted.

A third radial bearing 92 serves for the rotatable mounting of the input shaft 36 within the housing-fixed arrangement, the support plate 60 and the hub 58 having.

The third radial bearing 92 is preferred at the hub 58 or the support plate 60 adjacent to the drive motor 12 arranged.

The dual clutch arrangement 16 is generally operated automatically. For this purpose is an electronic control unit 94 provided, inter alia, designed a hydraulic circuit 96 head for. The control unit 94 has an electronic control unit 98 on, for example, also for controlling clutches of the transmission 18 can be designed. The control unit 98 For example, may also be connected to a parent vehicle control, for example. With a control of the drive motor 12 to interact.

The control unit 94 also has a regulator 100 on, which may be provided separately or as part of the control unit 98 can be trained. The controller may be, for example, a PI controller or the like.

The hydraulic circuit 96 includes a pump 102 that provides a line pressure. Furthermore, the hydraulic circuit includes 96 a pressure control valve 104 and a pressure measuring device 106 , The pressure control valve 104 is with the fluid channel 64 connected so that in one of the actuators (the right actuator in 1 ) a certain hydraulic pressure can be provided. It is understood that for the respective other actuator, a further pressure control valve and a further pressure measuring device may be provided, as well as a separate controller.

The actuators 68 . 70 are operated with force control or pressure regulation. For this purpose, the controller receives 100 from the pressure measuring device 106 via a return line 108 the current one Actual pressure P _{i of} the respective actuator. Furthermore, the controller receives 100 from the controller 98 a desired pressure P _s , via a line 110 ,

On a pipe 112 represents the regulator 100 a manipulated variable S ready, which is on the pressure control valve 104 acts. In this way, that of the control unit 98 predetermined target pressure P _s are adjusted for the respective actuator. By the direct operation of the friction clutches 42 . 44 is such a force or pressure control possible that generally excreted in lever-operated dry friction clutches.

By force or pressure control can be the dual clutch arrangement 16 regulate very quickly and precisely, so that fast and jerk-free circuits are possible.

Below are further embodiments of dual clutch arrangements 16 described in terms of structure and operation generally the dual clutch assembly 16 of the 1 correspond. The same elements are therefore provided with the same reference numerals. In the following, only the differences are discussed.

2 shows a dual clutch assembly 16 in which the plate radial bearing 56 about axial securing means 113 in the axial direction on the hub 58 is fixed. Furthermore, the central plate 54 on the outer ring of the plate radial bearing 56 fixed in the axial direction (axial securing means 114 ),

Further shows 2 an arrangement in which the piston housing 72 not to the hub 58 is welded, but via a circlip 116 is fixed (which can take, inter alia, axial forces). In this embodiment, a seal is provided to prevent leakage of hydraulic fluid from the actuator 118 provided the piston housing 72 against the hub 58 seals. In a similar way is a seal 120 provided, which serves as a piston bearing ring of the thrust bearing 74 against the piston housing 72 or against the hub 58 seals. In 2 It can also be seen that the piston of the actuators in each case by a separate piston element 122 may be formed adjacent to the respective bearing ring of the thrust bearing 74 is arranged. Alternatively, it is also conceivable that this bearing ring forms the piston element.

In the dual clutch arrangement 16 of the 3 are the thrust bearings 74 each as a double row thrust bearing with a first row 124 and a second row 126 educated. As a result, the comparatively high forces to be transmitted can be better absorbed or transmitted. The first row of double row thrust bearings 74 is in each case adjacent to the plate radial bearing 56 arranged. The second row is in this case arranged offset in the radial direction obliquely outwards, so that still a mirror image arrangement of the thrust bearings 74 in relation to the central plate 54 given is.

In 4 is shown a further embodiment, wherein the first output cage 82 on the radially outer periphery with a rotor 128 an electric machine 130 connected is. A stator 132 the electric machine 130 is on the case 62 established. This allows the dual clutch arrangement 16 Represent part of a hybrid powertrain.

In 4 is further shown that the hub 58 a fluid channel 134 may have, which is inoperative and, for example. By means of a plug 136 is closed. Such a hub 58 is therefore not only in dual clutch arrangements 16 can be used with dry double clutches, but also in such dual-clutch arrangements in which the friction clutches are designed as wet or wet-running friction clutches (for example, multi-plate clutches). For this alternative application, the hub 58 be used over the fluid channel 134 To supply cooling or other operating fluid to the wet friction clutches.

Claims (14)

Double clutch arrangement ( 16 ) for a motor vehicle ( 11 ), with a housing ( 62 ), a first dry friction clutch ( 42 ) and a second dry friction clutch ( 44 ), wherein the friction clutches ( 42 . 44 ) an input element ( 46 . 48 ), which with a drive shaft ( 28 ) is connectable, wherein the friction clutches ( 42 . 44 ) a first and a second output member ( 50 . 82 ; 52 . 84 ) having a first and a second transmission input shaft ( 38 . 40 ) are connectable, with a first actuator ( 68 ) for actuating the first friction clutch ( 42 ) and with a second actuator ( 70 ) for actuating the second friction clutch ( 44 ), wherein the actuators ( 68 . 70 ) on a housing-fixed hub ( 58 ) are arranged and the associated friction clutch ( 42 . 44 ) each via a thrust bearing ( 74 ) directly, characterized in that at the hub ( 58 ) one between the output members ( 50 . 82 ; 52 . 84 ) arranged central plate ( 54 ) is mounted radially, wherein the first output member ( 50 . 82 ) between the first input member ( 46 ) and the central plate ( 54 ) and the second output member ( 52 . 84 ) between the second input member ( 48 ) and the central plate ( 54 ) is clamped to the associated friction clutch ( 42 . 44 ) close. Dual clutch arrangement according to claim 1, wherein the hub ( 58 ) on the drive side (A) of Double clutch arrangement ( 16 ) with the housing ( 62 ) connected is. Double clutch arrangement according to claim 1 or 2, wherein the first output member ( 50 . 82 ) on the transmission side (G) of the dual clutch assembly ( 16 ) via a first radial bearing ( 88 ) is mounted on the housing. Dual clutch arrangement according to claim 3, wherein the second output member ( 52 . 84 ) on the transmission side (G) of the dual clutch assembly ( 16 ) via a second radial bearing ( 90 ) at the first output member ( 50 . 82 ) is stored. Double clutch arrangement according to one of claims 1 to 4, wherein the thrust bearings ( 74 ) in each case for the transmission of axial forces ( 77 ) of at least 4,000 Newton, in particular of at least 5,000 Newton. Double clutch arrangement according to one of claims 1 to 5, wherein the thrust bearings ( 74 ) are each self lubricated. Double clutch arrangement according to one of claims 1 to 6, wherein at least one of the thrust bearings ( 74 ) is designed as a double-row thrust bearing. Dual clutch arrangement according to one of claims 1 to 7, wherein the hub ( 58 ) at least one hydraulic fluid channel ( 134 ), which is inoperative. Dual clutch arrangement according to one of claims 1 to 8, wherein the friction clutches ( 42 . 44 ) longitudinal ( 13 ) arranged one behind the other and with respect to one to the longitudinal direction ( 13 ) transverse plane are arranged substantially mirror-symmetrically. Double clutch arrangement according to one of Claims 1 to 9, having a control unit ( 94 ) for driving the actuators ( 68 . 70 ), the control unit ( 94 ) is adapted to the friction clutches ( 42 . 44 ) with force control. Double clutch arrangement according to one of claims 1 to 10, wherein actuators ( 68 . 70 ) are designed as hydraulic actuators. Double clutch arrangement according to one of claims 1 to 11, wherein at least one actuator housing element is welded to the hub. Dual clutch arrangement according to one of claims 1 to 12, wherein an output member ( 50 . 82 ) of one of the friction clutches ( 42 . 44 ) with a rotor ( 128 ) of an electric motor ( 130 ) connected coaxially about the dual clutch arrangement ( 16 ) is arranged around. Method for actuating a dry friction clutch ( 42 . 44 ), in particular a dual-clutch transmission ( 14 ), wherein a housing-fixed actuator ( 68 . 70 ) the friction clutch ( 42 . 44 ) directly via a thrust bearing ( 74 ), wherein the actuator ( 68 . 70 ) via a controller ( 100 ), characterized in that a controlled variable (P _i ) of the regulator ( 100 ) from the actuator ( 68 . 70 ) applied force ( 77 ), and the friction clutch ( 42 . 44 ) an output member ( 50 . 82 ; 52 . 84 ) and an input member ( 46 . 48 ), and the output member ( 50 . 82 ; 52 . 84 ) between the input member ( 46 . 48 ) and a central plate ( 54 ) is trapped.

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