DE102008057656B4 - Coupling system with an automated friction clutch - Google Patents

Abstract

Coupling system (11) with an automated friction clutch (2, 18, 30) with a friction linings (43) clamped by means of a pressure plate (31) and an axially to this against the action of a lever system (22, 37) acted upon pressure plate (32) arranged a clutch disc (44), a hydraulic clutch release system (3) consisting of a master cylinder (12) with a master cylinder piston (28), a slave cylinder (14, 33) with a lever system (22, 37) by means of an interposition of a release bearing (21 , 39) the lever system (22, 37) acting slave cylinder piston (24, 38), a slave cylinder (14, 33) and master cylinder (12) connecting pressure line (13) and one with the master cylinder (12) in a predetermined position of the master cylinder piston ( 28) of this opened connection opening (29) which connects the master cylinder (12) and a supply reservoir (17) for pressure medium, one of a control unit ( 5) controlled actuator (4, 19) for actuating the master cylinder piston (28), wherein the control unit (5) for setting a predetermined via the friction clutch (2, 18, 30) to be transmitted torque to the actuator (4, 19) outputs control signals in which signal values dependent on the rotational speed of the friction clutch (2, 18, 30) are determined and output to the actuator (4, 19), characterized in that the connecting opening (29) is only at one rotational speed of the friction clutch (2, 18, 30 ) is released up to a predetermined limit value from the master cylinder piston (28), wherein the limit value is set so that a Druckauslgeich so long that a, the inertia and the geometric configuration of the lever system (22, 37) dependent centrifugal force escape of pressure medium can be prevented in the return tank (17).

Description

The invention relates to a clutch system with an automated friction clutch with a hydraulic clutch release system, which is actuated by an actuator controlled by means of a control device, having the features of the preamble of claim 1.

The DE 102 28 709 A1 discloses a method of adapting the adjustment, such as the tactile point or torque characteristic, as well as performing a snooping operation of an automated clutch in the driveline of a vehicle.

The DE 101 27 766 A1 discloses a method for compensating the influence of the speed on the characteristic curve of a clutch.

The DE 198 24 480 A1 discloses a method of controlling the operation of an automated clutch disposed in the drive train of a motor vehicle between a drive motor and a gearbox.

The DE 10 2005 027 066 A1 discloses a method of controlling the compensation of a hydraulic path of a clutch actuator, wherein the compensation is accomplished by sweeping an opening of a hydraulic path to a surge tank having a piston member, and opening the hydraulic path to the surge tank.

Clutch systems with automated friction clutches are well known. In the case of a hydrostatic actuated by means of a hydraulic clutch release system friction clutch, a master cylinder is actuated by an actuator, such as an electric motor. The master cylinder transmits the pressure generated at the master cylinder via a pressure line to the slave cylinder, which acts by means of an axially displaceable piston and interposition of a release bearing on a lever system which may be formed by a plate spring which acts rotatably and axially displaceable connected to a clutch housing pressure plate and clamped against a fixedly connected to the clutch housing pressure plate. Between the pressure plate and pressure plate, a clutch disc with friction linings is arranged, which form a frictional connection depending on the tension between the pressure plate and the pressure plate and close the friction clutch or open when the frictional connection is canceled.

The actuator is controlled by a control unit, which acts on the basis of stored in this calibration data, such as clutch characteristics, the actuator with signal values that cause a predetermined path to the friction clutch. The path in the chain of action of the clutch release system, for example in the actuator directly, is detected and corrected taking into account the existing between friction clutch and sensor translations. In this way, the path traveled can be assigned a torque to be transmitted via the friction clutch.

In a hydraulic clutch release system, the hydraulic path is exposed to external influences, such as the temperature or wear of the friction linings, which cause the volume of the pressure medium to vary. In the master cylinder, therefore, a connection opening to a non-pressurized overflow container is provided, a so-called sniffer bore. If it is an impressed friction clutch, which is opened by pressing the slave cylinder piston, the connection opening can be released with closed friction clutch by moving the master cylinder piston in a rest position and a pressure equalization. If the friction clutch is compressed, the pressure compensation can take place with the friction clutch fully open, since here the master cylinder piston is at rest and exposes the connection opening.

The automated friction clutch is recalibrated after a pressure equalization, for example, by re-assigning the so-called touch point of the friction clutch and this calibration data stored in the control unit and used in the assignment of the path to the transmitted via the friction clutch torque.

The object of the invention is to advantageously develop a clutch system with an automated friction clutch and to expand its scope.

The object is achieved by a clutch system with an automated friction clutch with a by means of a pressure plate and an axially against this acted upon the action of a lever system clamped pressure plate clamped friction linings a clutch disc, a hydraulic clutch release system consisting of a master cylinder with a master cylinder piston, a slave cylinder with a the lever system by means of an interposing a release bearing the lever system acting slave cylinder piston, a slave cylinder and master cylinder connecting pressure line and one with the master cylinder in a predetermined position of the master cylinder piston with closed friction clutch of this open connection opening which connects the master cylinder and a supply reservoir for pressure medium, an actuator controlled by a control unit for actuating the master cylinder piston, wherein the control unit for setting a predetermined via the friction clutch torque to be transmitted to the actuator outputs control signals, and the rotational speed of the friction clutch dependent signal values are determined and output to the actuator.

By taking into account the speed of the friction clutch centrifugal force effects on the clutch system can be compensated. For example, may be due to the speed-dependent action of centrifugal force on the lever system for actuating the friction clutch, for example, a pressure plate with the pressure plate spanning disc spring - especially if the lever system has larger axial shares - an axial displacement of the lever areas result, which are acted upon by the Kupplungsausrücksystem. As a result, a pressure on the slave cylinder piston is exerted centrifugally force dependent, which has an escape of pressure medium into the follow-up container, for example, when the construction of the friction clutch in the closed state of the friction clutch. With decreasing speed, a dead path when opening the friction clutch can lead to uncomfortable torque changes. In particular, it has been shown that when not clamped with the lever system slave cylinder piston or a so-called floating seal in the slave cylinder which seals the pressure chamber to the outside and is not axially fixed to the slave cylinder piston to reduce large wear due to pulsating movements of the slave cylinder piston, a corresponding dead path occurs. Because of this dead path, for example, the stored in the control unit touch point can no longer be assigned to the centrifugal force adjusting touch point. According to the invention, therefore, the control of the friction clutch is made centrifugally dependent.

Under the speed of the friction clutch is the speed of the clutch housing and the parts attached thereto such as pressure plate, pressure plate and lever system to understand, the clutch disc can take depending on the degree of opening of the friction clutch deviating speeds. The speed can be determined by means of a speed sensor. If the friction clutch is arranged, for example, on the crankshaft of an internal combustion engine or a rotor of an electric machine, then the rotational speed can be derived from its rotational speed, which is available, for example, in motor vehicles via a common data connection such as a CAN bus.

According to the invention, the closing of the connection opening in dependence on the centrifugal force acting on the friction clutch is provided to prevent centrifugal force escaping of pressure medium in the follow-up container. For this purpose can be controlled by the control unit, the actuator above a speed limit or a limit of the speed of the friction clutch so that the master cylinder closes the connection opening while the friction clutch is not yet disengaged. The limit is chosen so that at lower speeds, a pressure compensation can be done as long as possible, for example, in rapid temperature changes. The centrifugal force is dependent on the moment of inertia and the geometric design of the lever system. The determination of the limit value can be carried out empirically or for example by means of FEM methods.

According to a further advantageous embodiment example, the connection opening can remain open over an entire rotational speed range of the friction clutch with the friction clutch closed and after exceeding the rotational speed of the friction clutch over a predetermined limit and after return of the speed below a minimum value of the master cylinder piston moves by a predetermined path in the opening direction of the friction clutch and then moved back so far that the connection opening is opened. The limit value does not have to correspond to the previously mentioned limit value for closing the connection opening. Rather, can be tolerated with centrifugal force displacement of the slave cylinder piston and thus depending on the speed of the friction clutch and thus a detuning effect of the centrifugal force of the corresponding coupling design, assume at the open connection opening a displacement of pressure medium in the follower container under displacement of the slave cylinder as a result of centrifugal force is. If a correspondingly adapted limit value has been exceeded, the actuator can be operated to a slight extent after lowering the speed below the minimum value of the master cylinder, for example against the seal of the slave cylinder mounted in the pressure chamber again against the clamped, for example, with the lever system of the friction clutch and therefore this axially in a backward movement with decreasing centrifugal force follower slave cylinder piston and thus compensate for the resulting dead path. If the master cylinder is subsequently pulled back into its rest position, a so-called suction-suction effect arises, in which the seal of the master cylinder lifts off as a result of the negative pressure and allows a subsequent flow of the pressure medium from the after-reservoir. Is the master cylinder in its Rest position, the connection opening is unlocked and allows complete pressure equalization.

According to one embodiment of the invention, the wear of the friction linings is considered in the determination and definition of the limit values and / or the minimum value. As a result of wear of the friction linings, the lever system adjusts to the side of the loading by the slave cylinder piston. As a result, the axial component of the lever system, which increases under the influence of centrifugal force, so that - compared with friction linings without wear - even at lower speeds, the same influence of centrifugal force on the lever system, for example, the exhibited plate spring tongues of a disc spring occurs. Advantageously, therefore, depending on the wear of the friction linings, at least one limit value and / or minimum value is lowered. When bracing the friction linings by means of the lever system on the pressure and pressure plate is an equilibrium of forces, so that the effect of the tensioning force accumulator, for example, the force edge of a disc spring, other lever ratios subject, so that - in a known per se with decreasing friction lining thickness due to wear on the one hand, the radially inner, applied to the release bearing lever areas are set up and on the other higher release forces are necessary. It has proven to be advantageous to evaluate these balance of power in the control unit by, for example, the energy requirement of the actuator is determined, and to use as a measure of the wear in the centrifugal force-dependent control of the actuator. In this case, the position of the lever system determined in this way can be determined during an actuation process of the friction clutch, for example when the friction clutch is engaged or disengaged. In this case, the position of the lever system can be determined from a force / path behavior of the actuator during an actuation process of the friction clutch.

The compensation of the effects of centrifugal force, for example, a relation to the slave cylinder piston displaced seal by a control of the master cylinder piston in the opening direction is carried out only to a degree at which the friction clutch does not start to open. For this purpose, the slip of the friction clutch can be monitored and aborted when exceeding a predetermined size, moved the master cylinder piston for pressure equalization in the rest position and this process may be repeated as often as necessary. Furthermore, a detuning dimension can be formed from a position of the lever system and the rotational speed of the friction clutch and an actuator travel necessary for its compensation can be determined, wherein the determined actuator travel is limited to a value corresponding to an actuation position of the friction clutch in which a slip of the friction clutch during the Operation of the master cylinder in the opening direction of the friction clutch is negligible.

Another alternative provides that from a position of the lever system and the speed of the friction clutch Abstimmungsmaß is formed, which is superimposed on a stored in the control unit clutch characteristic for controlling a path of the actuator in response to a via the friction clutch to be transmitted moment.

It is understood that a method for operating the coupling system described by the invention is included.

• 1 einen schematisch dargestellten Antriebsstrang mit einem Kupplungssystem,
• 2 ein Kupplungssystem,
• 3 eine Reibungskupplung mit einem Nehmerzylinder und
• 4 einen Ablauf zur Steuerung eines Kupplungssystems.

The invention is based on the 1 to 4 explains in more detail:

• 1 a schematically illustrated drive train with a coupling system,
• 2 a coupling system,
• 3 a friction clutch with a slave cylinder and
• 4 a sequence for controlling a coupling system.

1 shows an embodiment of a schematically illustrated drive train 1 whose friction clutch 2 by means of an automated hydraulic clutch release system 3 from an actor 4 that of a control unit 5 is controlled, is operated. In the powertrain 1 it is a hybrid powertrain with an internal combustion engine 6 and an electric machine 7 that by means of the friction clutch 2 from the internal combustion engine 6 and by means of a torque converter 8th with the gearbox 9 is connectable. The electric machine 7 is arranged on the transmission side and can with open friction clutch 2 the vehicle via the drive wheels 10 drive alone or recuperate in overrun.

When disconnected from the gearbox 9 by means of a lockup clutch or at low speeds at which the torque converter can transmit only negligible moments due to its principle of action, can with closed friction clutch 2 the internal combustion engine 6 by means of the electric machine 7 directly or with the friction clutch first opened 2 and after an electric machine accelerated to a starting speed 7 closed clutch 2 be started in the impulse method. Such an operation places high demands on the hydraulic clutch release system 3 in which a secure assignment of one of the control unit 5 calculated and sent to the actuator 4 issued and implemented by this actuating path. Advantageously, such a drive train 1 controlled so that centrifugal forces occurring at the friction clutch 2 , Be considered in particular of the not apparent from this schematic representation lever system and the adverse effects caused eliminated.

2 shows a schematic representation of a possible embodiment of a coupling system 11 with a clutch release system with a master cylinder 12 and one by means of a line 13 Slave cylinder connected to the master cylinder 14 , Between the pipe parts 15 and 16 or integrated into master cylinder or slave cylinder can be a filter 17 , which can serve as a pressure relief valve and / or as a so-called Kribbelfilter be installed.

The hydraulic clutch release system actuates the friction clutch 18 of the coupling system 11 hydraulically by acting on the master cylinder 12 by means of the actuator 19 coming from the controller 5 is controlled. As a result, by means of a mechanical transmission 20 such as a piston rod pressure in the master cylinder 12 built and over the line 13 in the slave cylinder 14 , which is designed as Zentralausrücker, directed. The slave cylinder 14 brings over a release bearing 21 the necessary release force to the friction clutch 18 , or on the lever system 22 , For example, a plate spring or an operating lever. The type of tension of the lever system with the clutch housing 23 Defines whether it is an added or compressed friction clutch. Accordingly, the friction clutch becomes when the release bearing 21 through the slave cylinder piston 24 opened or in the case of a - not shown pressed-friction clutch - by the slave cylinder piston 24 closed. The transmission input shaft 25 transmits when the friction clutch is closed 18 the torque of the - not shown-, with the friction clutch rotatably connected internal combustion engine via the clutch disc 26 to a not-shown gear and then to the drive wheels of a motor vehicle.

Will the friction clutch 18 operated at high speed, learns the lever system 22 especially at even higher axial portion of the radially inner lever segments 27 a centrifugal force radially outward, causing the release bearing 21 and thus the slave cylinder piston 24 the slave cylinder 14 is pressed into the slave cylinder housing and a volume corresponding to the axial displacement and the piston surface of the slave cylinder piston via the line 13 and the master cylinder 12 in the return tank 17 is displaced. If the speed decreases again, the lever segments return again and usually under bias by means of the release bearing 21 Slave cylinder pistons resting against the lever segments 24 will also be moved back. The not apparent, under pressure on the slave cylinder piston 24 fitting seal, which is not due to wear on the slave cylinder piston 24 set seal remains in the maximum, caused by the centrifugal deflection and causes without initiating further action in the next disengaging a dead path until it has unlocked again to the slave cylinder piston. According to the invention by the control unit 5 Steps initiated to eliminate this effect before the next disengagement of the friction clutch.

For this purpose, upon reaching a predetermined speed of the master cylinder piston 28 from the actor 5 to the extent that the connection opening 29 to the trailer tank 17 is closed. In this way, a pressure equalization is no longer possible and slave cylinder piston 24 including seal stay in place. Alternatively, one of the slave cylinder piston 24 be brought back into contact with the slave cylinder piston due to centrifugal force influence by the donor cylinder piston 28 is displaced in the release direction until the seal back to the slave cylinder piston 24 is created. The master cylinder piston is only moved so far that a predetermined slip limit of the friction clutch is not reached. The return movement of the slave cylinder piston 24 requires a pressure equalization by pressure medium from the after-reservoir 17 is sucked.

3 shows a partial section through a friction clutch 30 with a non-rotatably connected to a crankshaft of an internal combustion engine, not shown, pressure plate 31 , one of a lever system 37 applied pressure plate 32 and a slave cylinder 33 , the cover festfest by means of a rolling bearing 34 rotatable on one with the clutch housing 35 connected sheet metal part 36 is included. The slave cylinder piston 38 acted upon by the release bearing 39 the radially inner lever segments 40 , With a displacement of the slave cylinder piston 38 in the direction of the friction clutch 30 turns the lever system 37 , in the non-actuated state of the friction clutch due to its disc spring properties by means of the force margin 41 the pressure plate 32 with the pressure plate 31 braced to the annular turning line 42 , so that the tension of the pressure plate against the pressure plate 31 wears off and the means of friction linings 43 between pressure plate 32 and pressure plate 31 tensioned clutch disc 44 connected to the transmission input shaft 45 rotatably under Interposition of a torsional vibration damper 46 is connected, is rotatable.

At high speeds of the friction clutch 30 becomes the lever system 37 accelerated due to centrifugal force and because of the axial portions radially within the rotational line 42 The lever segments are in the direction of the slave cylinder 33 shifted, causing the slave cylinder piston 38 in the direction of slave cylinder housing 47 is relocated. The illustration shows a slave cylinder piston 38 , after a centrifugal load due to the spring force of the spring 48 at lower speeds the decreasing lever segments 40 followed, while not on the slave cylinder piston 38 Tailored seal 49 at the position of the centrifugal force induced deflection position of the slave cylinder piston 38 has stopped.

4 shows an embodiment of a process 50 to take account of centrifugal forces in a software for controlling a friction clutch. The method for controlling the friction clutch, for example, according to expiration 1 in the control unit 5 ( 1 and 2 ).

In block 51 the detuned value VSM is determined, for example, estimated or calculated. The Vermaßungsmaß VSM includes the failure of the hydraulic clutch release system by centrifugal force at high speeds of the friction clutch. Furthermore, the centrifugal force can be increased by an uplifting lever system, so that for the detuning a map can be formed, which is at least spanned by the wear of the friction linings of the friction clutch and the rotational speeds of the friction clutch. This map is updated continuously, preferably in real time. The wear can be done by evaluating the force / travel behavior of the actuator. For determining the force or the power or consumed energy, electrical variables, for example a current flowing over a path section, a voltage drop or the like can be used. With the appropriate parameterization, the detuning dimension returns to what extent the seal is likely to be displaced with respect to the slave cylinder piston.

In block 52 the slip limit SG of the friction clutch is determined, for example, estimated or calculated. The slip limit SG marks the path position at which the friction clutch reaches a predetermined slip during a disengagement process. This limit can be set so that, although slip occurs, for example, a differential speed between the crankshaft and the transmission input shaft of 20-100 1 / s, but no break in the torque transmission is felt. By determining the slip limit, a piston stroke of the master cylinder piston can be determined, which indeed generates a pressure in the slave cylinder, but does not yet disengage the friction clutch beyond a desired, appreciable extent. As the basis of the determination of the underlying variables, for example, the determined before the disturbance by the influence of centrifugal force sensing point and / or operating point without slippage and the rest position of the master cylinder piston serve.

In the branch 53 a decision is made as to whether the detuning parameter VSM parameterized in the dimension of a path is smaller than the slip limit SG and an adjustment, that is to say, an actuation of the master cylinder for exerting pressure on the slave cylinder is to be released at all. If, for example, the detuning amount VSM is greater than the slip limit SG, the friction clutch would be opened further than the slip limit in the case of complete compensation. Adjustment may still be prohibited if, for example, the number of compensations has been exceeded in a given period of time to minimize seal wear over life. Furthermore, for example, at low temperatures, where the pressure medium has low viscosity, a balance can be suspended.

Is one of the conditions in branching 53 not met, will be in block 54 the detuning dimension VSM is taken into account in the calculation of the clutch characteristic, for example by wholly or partially fitting the detuning dimension VSM dimensioned as a path to the path of the frictional clutch in a coupling characteristic of the torque to be transmitted via the path. Below is in the branch 55 Checks whether the VSM detuning exceeds a predetermined limit. If this is the case, in block 56 changed the operating mode, for example, by the dynamics of the actuator is reduced and the friction clutch is operated at a reduced speed and / or certain operating modes that make high demands on the control of the friction clutch, such as sports mode and / or in hybrid vehicles sailing, recuperation, start / stop Operations and the like. If the limit is not exceeded, bypassing block 56 directly to the calculation and conversion of the clutch characteristic and to control the actuator by means of this clutch characteristic in block 57 passed.

Are in the branch 53 fulfilling both conditions will be ramified 58 Check that the gasket is far enough away from the slave cylinder piston that an adjustment is required. For this purpose, the detuning can be subjected to a further limit value. Will depend on this Limit decided that the seal does not need to be applied to the slave cylinder piston, is in block 59 decided whether a so-called snooping should be performed. Sniffing is to be understood as the withdrawal of the master cylinder piston into the rest position, in which the connection opening to the after-reservoir is released and a pressure equalization with the after-reservoir is made possible. The decision as to whether a snooping operation should be performed at very low detuning rates depends on operating parameters, such as temperature changes, time since the last snooping operation, operating or calibration data that greatly varies over time, and the like.

If a snooping process is to be performed, this is done in block 60 , where at the end of the snooping process in block 61 the detuning VSM is reset. Will be in the branch 59 decided that no snooping should be done, then in block 57 calculated the clutch characteristic and implemented on the actuator.

Will be in the branch 58 If the seal is found to be an impermissible distance from the slave cylinder, the seal becomes block 62 "Captured". This means that the master cylinder piston from the actuator to the detuning VSM, due to branching 53 is smaller than the slip limit SG of the friction clutch, is moved, so that the seal is applied due to the pressure built up by the master cylinder piston back to the slave cylinder piston. Subsequently, the master cylinder piston is moved to the rest position and opened the connection opening to the reservoir and thereby allows pressure equalization. In the block 57 the clutch characteristic is calculated and converted at the actuator.

LIST OF REFERENCE NUMBERS

1

powertrain

2

friction clutch

3

clutch release

4

actuator

5

control unit

6

Internal combustion engine

7

electric machine

8th

torque converter

9

transmission

10

drive wheel

11

coupling system

12

Master cylinder

13

management

14

slave cylinder

15

line part

16

line part

17

An expansion reservoir

18

friction clutch

19

actuator

20

Mechanical transmission

21

release bearing

22

lever system

23

clutch housing

24

Slave cylinder piston

25

Transmission input shaft

26

clutch disc

27

lever segment

28

Master cylinder piston

29

connecting opening

30

friction clutch

31

pressure plate

32

printing plate

33

slave cylinder

34

roller bearing

35

clutch housing

36

Sheet metal part

37

lever system

38

Slave cylinder piston

39

release bearing

40

lever segment

41

force boundary

42

rotary line

43

friction lining

44

clutch disc

45

Transmission input shaft

46

torsional vibration dampers

47

Slave cylinder housing

48

feather

49

poetry

50

procedure

51

block

52

block

53

branch

54

block

55

branch

56

block

57

block

58

branch

59

branch

60

block

61

block

62

block

Claims (6)

Coupling system (11) with an automated friction clutch (2, 18, 30) with a friction linings (43) clamped by means of a pressure plate (31) and an axially to this against the action of a lever system (22, 37) acted upon pressure plate (32) arranged a clutch disc (44), a hydraulic clutch release system (3) consisting of a master cylinder (12) with a master cylinder piston (28), a slave cylinder (14, 33) with a lever system (22, 37) by means of an interposition of a release bearing (21 , 39) the lever system (22, 37) acting slave cylinder piston (24, 38), a slave cylinder (14, 33) and master cylinder (12) connecting pressure line (13) and one with the master cylinder (12) in a predetermined position of the master cylinder piston ( 28) of this opened connection opening (29) which connects the master cylinder (12) and a supply reservoir (17) for pressure medium, one of a control unit ( 5) controlled actuator (4, 19) for actuating the master cylinder piston (28), wherein the control unit (5) for setting a predetermined via the friction clutch (2, 18, 30) to be transmitted torque to the actuator (4, 19) outputs control signals in which signal values dependent on the rotational speed of the friction clutch (2, 18, 30) are determined and output to the actuator (4, 19), characterized in that the connecting opening (29) is only at one rotational speed of the friction clutch (2, 18, 30 ) is released up to a predetermined limit value from the master cylinder piston (28), wherein the limit value is set so that a Druckauslgeich so long that a, the inertia and the geometric configuration of the lever system (22, 37) dependent centrifugal force escape of pressure medium can be prevented in the return tank (17). Coupling system (11) according to Claim 1 , characterized in that the connection opening (29) remains open over an entire rotational speed range of the friction clutch (2, 18, 30) with the friction clutch (2, 18, 30) closed and after exceeding the rotational speed of the friction clutch (2, 18, 30) is moved beyond a predetermined limit value after the return of the rotational speed below a minimum value of the master cylinder piston (28) by a predetermined distance in the opening direction of the friction clutch (2, 18, 30) and then moved back so far that the communication port (29) is opened. Coupling system (11) according to one of Claims 1 or 2 , characterized in that at least one limit value and / or minimum value is modified depending on a position of the lever system (22, 37) when the friction clutch (2, 18, 30) is closed. Coupling system (11) according to Claim 2 and 3 , characterized in that from a position of the lever system (22, 37) and the rotational speed of the friction clutch (2, 18, 30) a detuning (VSM) is formed and a necessary for its compensation Aktorweg is determined, wherein the determined Aktorweg to a value is limited, which corresponds to an operating position of the friction clutch (2, 18, 30), in which slippage of the friction clutch (2, 18, 30) during actuation of the master cylinder (12) in the opening direction of the friction clutch (2, 18, 30) negligible is. Coupling system (11) according to Claim 2 or 3 , characterized in that the position of the lever system (22, 37) from a force / path behavior of the actuator (4, 19) during an actuation operation of the friction clutch (2, 18, 30) is determined. Coupling system (11) according to Claim 1 , characterized in that from a position of the lever system (22, 37) and the rotational speed of the friction clutch (2, 18, 37) a detuning (VSM) is formed, the one in the control unit (5) stored clutch characteristic for controlling a path of the actuator (4, 19) is superimposed in response to a via the friction clutch (2, 18, 30) to be transmitted torque.

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