DE102014216279A1 - Method for protecting a clutch actuator of a clutch actuation system, preferably for a motor vehicle - Google Patents

Abstract

The invention relates to a method for protecting a Kupplungsaktorik for a clutch actuation system, preferably for a motor vehicle, which controls a self-closing clutch (4) by a first piston (18) of a master cylinder (13) of the Kupplungsaktorik is adjusted by an electric motor, whereby a hydrostatic path (14) for actuating the clutch (4) a second piston (16) of a slave cylinder (15) is moved, and a maximum travel of the second piston (16) is limited by a stop. In a method of ensuring that the clutch actuator is not destroyed by improper operations, a non-permanent stop is used, the stop being considered actuated when the second piston (16) has traveled a stop travel which is a predetermined distance is reduced relative to the mechanical stop, wherein a maximum position of a hydrostatic clutch actuator (12) is defined in dependence on the traveled stroke stroke.

Description

The invention relates to a method for protecting a clutch actuator of a clutch actuation system, preferably for a motor vehicle, which controls a self-closing clutch by a first piston of a master cylinder of the Kupplungsaktorik is adjusted by an electric motor, whereby a second piston of a slave cylinder process over a hydrostatic path for actuating the clutch is and a maximum travel of the second piston is limited by a stop.

From the DE 10 2012 218 255 A1 For example, a method for driving a clutch with a hydrostatic actuator is known, which comprises a threaded spindle which is rotated in order to move a piston of a master cylinder in the axial direction, wherein a distance covered by the piston is determined directly or indirectly by means of a sensor device.

If self-closing couplings, which are also referred to as non-actuated closed couplings, used in combination with a hydrostatic clutch actuator, the clutch is actuated via a hydrostatic circuit. The piston of a master cylinder is driven by an electric motor and actuated via a hydraulic fluid in the system, a second piston in a slave cylinder. The second piston of the slave cylinder acts on the lever spring tips, which then lifts on actuation of a clutch plate of a clutch disc and thus interrupts the transmission of a clutch torque via the clutch. In the unactuated state, the preloaded lever spring closes the clutch.

In contrast to conventional clutches operated by a clutch pedal, the ratio between the measurable travel of the hydrostatic clutch actuator and the travel of the piston of the slave cylinder is very small. Errors in the positioning of the hydrostatic clutch actuator are transferred directly to the piston of the slave cylinder. This situation is reinforced by the fact that a displacement detection of the hydrostatic clutch actuator by itself has very large tolerances, which are significantly greater than in a manually operated system. A large part of the tolerances of the hydrostatic actuator relates to the accuracy of the installation position of an absolute travel sensor.

In a defined position of the hydrostatic clutch actuator results in a large inaccuracy of the position of the piston of the slave cylinder, as in 3 is shown. In order to safely open the clutch, a certain stroke of the hydrostatic clutch actuator (HCA) must be approached taking into account all possible tolerances that occur due to the geometry of the individual components of the clutch actuators, such as piston area tolerances, friction variations, absolute value sensor errors of the hydrostatic actuator, new condition and others become. How out 3 it can be seen, the position of the hydrostatic clutch actuator (HCA) of 13.3 mm must be approached at a stroke of the piston of the slave cylinder, for example, 6.3 mm. However, if the hydrostatic clutch actuator (HCA) retards a distance of 13.3 mm, an adjustment distance in the slave cylinder can amount to 10.8 mm. Due to space constraints, however, the maximum stroke of the slave cylinder is limited to 9.6 mm. However, in order to move the coupling into the safe-opening position, the maximum permitted travel of the piston of the slave cylinder can be exceeded by the path of the hydraulic clutch actuator (HCA) due to the tolerance scattering, up to a distance of 10.8 mm. If the maximum permissible lift of the slave cylinder is exceeded, hydraulic fluid escapes and the system is destroyed, whereby a clutch actuation is no longer possible.

The invention has for its object to provide a method for protecting the Kupplungsaktorik, in which, despite tolerances, component problems and only a limited number of stop detectors clutch components remain undamaged.

According to the invention, this object is achieved in that a non-permanent stop is used, wherein the stop is considered to be operated when the second piston of the slave cylinder has covered a Anschlagungsweg, which is reduced by a predetermined distance from the stop, depending on the traveled stroke a maximum position of a hydrostatic clutch actuator is defined. Under a non-fatigue stop is to be understood hereinafter a stop, which is not designed for the entire life of the slave cylinder. This ensures that the stop in the slave cylinder is not actuated by most systems that include the clutch and the hydrostatic clutch actuator. Due to the lack of operation is reliably prevented that the slave cylinder is damaged. By determining the maximum position of the hydrostatic clutch actuator as a function of the non-fatigue stop it is ensured that in this position of the slave cylinder, the clutch is securely opened and thus no clutch torque is transmitted.

Advantageously, the clutch actuation becomes successful until the detection of the Actuation stroke of the second piston actuated, wherein upon successful detection of the stroke of the second piston, a first position of the hydrostatic clutch actuator, which is smaller than the maximum position, is considered to be achieved, in which the clutch is securely opened. Since in this case the maximum position of the hydrostatic clutch actuator is certainly not approached, thus eliminating forces that operate the slave cylinder over the predetermined maximum stroke and thus destroy the system.

In one embodiment, the maximum position of the hydrostatic clutch actuator is reduced by a predetermined value in the absence of detection of the stop travel of the second piston of the slave cylinder. This ensures that the clutch is always safely opened due to the position assumed by the hydrostatic clutch actuator and that the maximum lift of the slave cylinder is not exceeded.

In one variant, the determination of the maximum position of the hydrostatic clutch actuator in dependence on tolerances of a, the stop travel of the second piston of the slave cylinder detecting displacement sensor. In this case, not only the tolerances of the individual system units are taken into account, but at the same time those of the measuring sensors, so that an erroneous operation of the clutch actuator is reliably prevented.

In a further development, the setting of the maximum position of the hydrostatic clutch actuator and / or the non-fatigue stop during a tape end check a production of a clutch comprehensive transmission takes place. During the band end test, the clutch system learns due to the proposed method, both the maximum position of the hydrostatic clutch actuator and the position of the non-fatigue stop, which are then used in the operation of the transmission in the motor vehicle over its lifetime.

In one embodiment, as part of the tape end check, a touch point adaptation is performed, defining a standby point of the hydrostatic clutch actuator in which the clutch is considered open. Due to this setting, the routines that are performed during the tape end check can be processed reliably.

Advantageously, the readiness point of the hydrostatic clutch actuator is smaller than its maximum position. The standby point, which represents the touch point plus a tolerance of x mm, indicates that the clutch is defined as open for further operation. Since this touch point and thus the standby point represents an important parameter in the control of the clutch during operation of the motor vehicle, this must not be above the maximum position of the hydrostatic clutch actuator to prevent damage to the Kupplungsaktorik.

In one variant, a clutch of a drive train of a hybrid vehicle is used as a clutch. In this case, errors that can be transmitted during the positioning of the hydrostatic clutch actuator on the piston of the slave cylinder, minimized.

The invention allows numerous embodiments. One of them will be explained in more detail with reference to the figures shown in the drawing.

Show it:

1 Schematic representation of a drive train of a hybrid vehicle.

2 Schematic representation of a clutch actuation system in the hybrid vehicle,

3 a representation of the translation spread of a clutch with a hydrostatic clutch actuator according to the prior art.

The schematic diagram of a drive train 1 a hybrid vehicle is in 1 shown. This powertrain 1 includes an internal combustion engine 2 and an electric motor 3 , Between the combustion engine 2 and the electric motor 3 is right behind the combustion engine 2 a separating clutch 4 arranged. internal combustion engine 2 and separating clutch 4 are over a crankshaft 5 connected with each other. The electric motor 3 has a rotatable rotor 6 and a fixed stator 7 on. The output shaft 8th the separating clutch 4 is with a gearbox 9 connected, which contains a coupling element, not shown, for example, a second clutch or a torque converter, that between the electric motor 3 and the transmission 9 is arranged. The gear 9 transmits that from the internal combustion engine 2 and / or the electric motor 3 generated torque on the drive wheels 10 of the hybrid vehicle. The separating clutch 4 and the gearbox 9 form a gear system 11 , wherein the separating clutch 4 from a hydrostatic clutch actuator 12 is controlled.

In 2 is the hydrostatic clutch actuator 12 for actuating the separating clutch 4 shown in simplified form. The hydrostatic clutch actuator 12 includes a master cylinder 13 , via a hydraulic line, also referred to as a pressure line 14 with a slave cylinder 15 connected is. In the slave cylinder 15 is a slave piston 16 mounted axially movable, with the interposition of a release bearing 17 the separating clutch 4 actuated. In the master cylinder 13 is a master piston 18 mounted axially movable. From the master piston 18 go a piston rod 19 out, in the longitudinal extension of the master cylinder 13 together with the master piston 18 is translationally movable. The piston rod 18 of the master cylinder 13 is via a threaded spindle 20 with an electromotive actuator 21 coupled. The electromotive actuator 21 includes an electric motor 22 and an evaluation unit 23 , The threaded spindle 20 sets a rotary motion of the electric motor 22 in a longitudinal movement of the piston rod 19 or the master piston 18 around. Parallel to the master cylinder 13 is a first way sensor 24 arranged while a second path sensor 25 the displacement of the slave piston 16 on the slave cylinder 15 detected.

In addition, it is assumed that it is the disconnect clutch 4 to an unactuated closed clutch (self-closing coupling) is. In the production of such, the disconnect clutch 4 comprehensive transmission system 11 becomes the transmission system 11 subjected to a band end test, on which stops both for the slave piston 16 the slave cylinder 15 as well as ways that the hydrostatic clutch actuator 12 can be learned, in order to prevent a destruction of the clutch actuator. This is done on a test bench on the tested transmission system 11 executed an actuating stroke, wherein the hydrostatic clutch actuator 12 by the movement of the master piston 18 of the master cylinder 13 assumes a predetermined position, via the hydraulic fluid to the slave piston 16 the slave cylinder 15 is transmitted, which also occupies a corresponding position. Due to the tolerances of the different transmission systems 21 It will occur that part of the transmission systems 21 reached the stop while another part of the transmission systems 21 not reached this stop. To ensure that even with this wide dispersion destruction of the components of the transmission system 21 is prevented, two strategies are distinguished. In both strategies, a non-permanent mechanical stop is used, which means that this stop is mechanically designed so that it survives only a limited number of actuation strokes. However, the non-fatigue stop is not capable of one million actuations of the transmission system 21 which are necessary over the lifetime to endure. In the case of the non-fatigue stop, the stop travel of the slave piston to be detected is thereby detected 16 the slave cylinder 15 set so that the stop is considered reached when a predetermined distance value by which the stop position is reduced by the second slave piston 16 the slave cylinder 15 is achieved, which means the displacement sensor 25 is detected.

In the case that this predetermined distance value when operating the transmission system 21 successful through the displacement sensor 25 is detected, it is assumed that with this operating stroke, the state of the separating clutch 4 guaranteed to be safe. That means the master cylinder 13 of the hydrostatic clutch actuator 12 occupies a position in which by the slave cylinder 15 the separating clutch 4 Reliably opened without damaging it. In this consideration, it is assumed that the impact forces and the diaphragm spring paths that the disconnect clutch 4 operate within specified tolerances. From this design results, for example, a minimum distance value for a safely opened disconnect clutch 4 for example, 1 mm, which means that the stop travel to be detected, which is the second slave piston 16 the slave cylinder 15 travels at an actuating stroke, 1 mm before the actual mechanical stop ends.

For the definition of the maximum position of the hydrostatic clutch actuator 12 In addition, the tolerances of the displacement sensors 24 takes into account which the way of the master piston 18 of the master cylinder 13 detected. This maximum position corresponds to a stroke of the slave cylinder 15 , which is 0.5 mm smaller than the position of the stop of the slave cylinder 15 , This ensures that the self-closing disconnect clutch 4 at this defined path of the hydrostatic clutch actuator 12 opens sufficiently for the tape end routines to be performed. At the same time, there is the possibility that the stop of the slave piston can be approached once during a new startup, for example in the case of servicing a component replacement.

The second possibility of setting maximum positions of the hydrostatic clutch actuator 12 and the stop is considered on the premise that the slave piston 16 the slave cylinder 15 has not executed the defined stroke stop, which is why this can not be detected. It is assumed that the impact forces are in order, but not the diaphragm springs. In this case, every transmission system 12 subjected to an operating stroke on the test stand, in which it is assumed that the hydrostatic clutch actuator 12 the separating clutch 4 safely opens plus covers a defined additional path, in which again the tolerances of the displacement sensor 24 be taken into account. In transmission systems 21 , which the The maximum stroke of the hydrostatic clutch actuator will not be exceeded 12 limited to the driven stroke by 0.5 mm.

In both options explained is the separating clutch 4 each actuated sufficiently, which is why the request of the stop and the permitted plate spring travel are taken into account. The maximum position of the hydrostatic clutch actuator 12 is now just as the attack learned and will be in the transmission system 21 stored and when starting the separating clutch 4 used during operation in the motor vehicle, with damage or destruction of the Kupplungsaktorik over the life of the actuation of the slave cylinder 16 reliably prevented.

Starting from the maximum position of the hydrostatic clutch actuator 12 and the learned stop travel during the tape end test, a touch point adaptation is performed, in which, depending on the detected touch point, in which the separating clutch 4 begins to transmit a clutch torque, a standby point is defined at which the disconnect clutch 4 is reliably open and thus transmits no clutch torque. The standby point is composed of the touch point plus x mm.

By using a non-durable stop in the separating clutch 4 or in the slave cylinder 15 becomes a driving strategy of the separating clutch 4 selected, in which not every operation, the stop is detected, but on the one hand, the clutch actuator protected from damage and on the other hand, the disconnect clutch 4 is sufficiently impressed.

LIST OF REFERENCE NUMBERS

1

 powertrain

2

 internal combustion engine

3

 electric motor

4

 separating clutch

5

 crankshaft

6

 rotor

7

 stator

8th

 output shaft

9

 transmission

10

 drive wheels

11

 transmission system

12

 hydrostatic clutch actuator

13

 Master cylinder

14

 hydraulic line

15

 slave cylinder

16

 slave piston

17

 release bearing

18

 master piston

19

 piston rod

20

 screw

21

 electromotive actuator

22

 electric motor

23

 evaluation

24

 Position Sensor

25

 Position Sensor

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012218255 A1 [0002]

Claims (8)

Method for protecting a clutch actuator for a clutch actuation system, preferably for a motor vehicle, which has a self-closing clutch ( 4 ) is triggered by a first piston ( 18 ) of a master cylinder ( 13 ) the Kupplungsaktorik is adjusted by an electric motor, whereby over a hydrostatic path ( 14 ) for actuating the clutch ( 4 ) a second piston ( 16 ) of a slave cylinder ( 15 ), wherein a maximum travel of the second piston ( 16 ) is limited by a stop, characterized in that a non-permanent stop is used, wherein the stop is considered to be actuated when the second piston ( 16 ) has covered a stop travel, which is reduced by a predetermined distance value relative to the mechanical stop, wherein a maximum position of a hydrostatic clutch actuator (depending on the traveled stop travel) ( 12 ) is defined. A method according to claim 1, characterized in that the clutch actuator until successful detection of the stop travel of the second piston ( 16 ) is actuated, wherein upon successful detection of the stop travel of the second piston, a first position of the hydrostatic clutch actuator ( 12 ), which is smaller than the maximum position, is considered reached, in which the clutch ( 4 ) is safely opened. A method according to claim 2, characterized in that in the absence of detection of the stop travel of the second piston ( 16 ) of the slave cylinder ( 15 ) the maximum position of the hydrostatic clutch actuator ( 12 ) is reduced by a predetermined value. Method according to Claim 2 or 3, characterized in that the determination of the maximum position of the hydrostatic clutch actuator ( 12 ) in response to tolerances of one, the stop travel of the second piston ( 16 ) of the slave cylinder ( 15 ) detecting displacement sensor ( 25 ) he follows. Method according to at least one of the preceding claims, characterized in that the setting of the maximum position of the hydrostatic clutch actuator ( 12 ) and / or the non-fatigue stop during a tape end test of a manufacture of a, the coupling ( 4 ) comprehensive transmission ( 9 ) he follows. A method according to claim 5, characterized in that in the context of tape end check a Tastpunktadaption is performed, wherein a standby point of the hydrostatic clutch actuator ( 12 ) is defined, in which the coupling ( 4 ) is considered open. A method according to claim 6, characterized in that the readiness point of the hydrostatic clutch actuator ( 12 ) is smaller than its maximum position. Method according to at least one of the preceding claims, characterized in that a separating clutch ( 4 ) of a drive train ( 1 ) of a hybrid vehicle is used.

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