DE4427942C2 - Hydraulic actuation system for a friction clutch - Google Patents

Description

The invention relates to a hydraulic Actuating system for a friction clutch in a vehicle, in particular according to the features of the preamble of claim 1.

DE-OS 34 27 791 a generic disengaging device emerged which is a housing with a one-sided protruding from this Has guide tube. There is an axial displacement on the guide tube plier piston resting on the end of a clutch release bearing guided, which is a radial distance between the guide tube and the Housing bridged. For a positive connection of the piston on Clutch release bearing with a preload serves one between the piston and Compression spring inserted in the housing. For pressurizing the annular piston, which in a correspondingly out protrudes pressure chamber, there is a pressure medium connection on the housing seen from which a tap hole leads to the pressure chamber. This known device requires a large axial space overall, due to the axial arrangement of the individual components. Furthermore the device is not adequately protected against contamination, such as it occurs in clutch housings of vehicles.

Another disadvantage arises from the almost exclusively Steel-made individual components in the form of turned parts or Castings that cause high manufacturing costs and a high weight exhibit. As sealing elements on machined peripheral surfaces can only be carried out with comparatively great effort  surface roughness can be achieved, the long life of the seal allow association.

The object of the invention is therefore to optimize the installation space and weight Mated release device to create that can be produced inexpensively and is easy to assemble and has a long service life.

By the features listed in claim 1 solved this task.

The structure of the release device according to the invention sees a piston before, which has a sheet metal sleeve projecting axially on one side, which in a hole, advantageously designed as a stepped hole, the Druckge house is sealed. The sheet metal sleeve is arranged so that this at least partially encloses a lateral surface of the piston. The one Sheet metal sleeve with a small wall thickness optimizes the installation space tion, especially in the radial direction, as this saves space not pressurized release device in the corresponding radial molded areas of an annular space of the guide tube can be inserted is. According to the invention, the pressure housing further has one side axially shaped collar. This takes the pressure housing in one Neutral position, d. H. if the friction clutch is not actuated, all sliding components, such as. B. the release bearing.

This advantageously results in contamination protected arrangement in which the release bearing as well as the slave cylinders are shielded. This measure is particularly advantageous for friction clutches in which the abrasion of the friction lining Drive plate all components of the release device of a strong Are exposed to dust when they are unprotected, causing the Function of the release device could be adversely affected.

A step-like bore is made in the pressure housing brings in which the guide tube is fixed in position and in the one on the Guide tube guided, sleeve-shaped piston including of the release bearing located on the end of the piston is insertable. This design is conducive to creating a compact  Building disengaging device, since individual components fit into each other are slidable.

Further advantageous refinements of the invention are shown in FIGS dependent claims 2 to 24 listed.

An embodiment of the invention provides a guide according to claim 2 tube forward with a longitudinal extension that the width of the release forward direction corresponds or covers this. It advantageously results no addition due to this one-piece design of the guide tube of tolerances in the axial direction to the neighboring components, in Comparison to a guide tube consisting of several individual parts or components through which the axial width of the release device is determined.

According to claim 3, the guide tube also serves to receive a Sealing ring on the end facing away from the clutch release bearing Guide tube. The sealing ring inserted inside the guide tube ensures a seal to the gear housing. Through this out the release device is provided with the gearbox seal tion advantageous to a pre-assembled, together on the gearbox screw-on unit.

In a further embodiment of the invention according to claim 4 comes out Sheet metal machined guide tube for use, which on the in Pressure housing located end in the form of an open on one side, in Direction of the release bearing facing annular space preferably a flange is formed. This is advantageous Annulus designed as part of the pressure chamber for the slave cylinder and in the neutral position of the release device for receiving Determines components that are axially displaceable in the annular space. Of the total pressure space for the slave cylinder is limited by the axial projecting section of the sheet metal sleeve, a bore wall of the pressure housing, an annular piston surface of the piston and different sections of the guide tube, such as one cylindrical surface and the sheet metal edge forming at the end. The pressure chamber according to the invention consequently consists of one another  connected, circularly shaped pressure rooms of different Diameter together.

According to claim 5 it is provided in the pressure chamber in front of a guide sleeve watch a transition area between the guide tube and the Pressure housing covered. The cylindrical shape is advantageous Guide sleeve centering the guide tube outside the pressure housing.

According to claim 7, the sheet metal sleeve, which is partially the jacket encloses the surface of the piston, with a flange at the end see that is included or cast in the piston. Through this Training will be an advantageously firm bond between the piston and the sheet metal sleeve ensured.

To achieve an effective axial fixation of the guide tube in the Pressure housing is provided according to claim 8, a radial disc non-detachably arranged on the outer surface of the annular space and on Pressure housing is attached.

The inventive design of the piston for the slave cylinder sees according to claim 9 a rotating on the piston in an annular groove position-fixed board, on which the clutch is axially unilateral supports bearing. The board is still on the radial interior and Provide the outer zone with the sheet metal sleeve and a ring shoulder, their axial sections in different zones of the bore or the stepped bore of the pressure housing. It is advantageous by the radial outer ring shoulder an effective coverage of the Clutch release bearing from considered secondary seal of the Given slave cylinder.

To create an alternative arrangement of the clutch release bearing on the piston is the piston with a stepped according to claim 10 Provide section on which a guide sleeve can be mounted in a rotationally fixed manner is. The guide sleeve, which is preferably made of plastic, has end, d. H. a board pointing to the pressure housing, which with its axially inner portion is embedded in the guide sleeve  and its radial section as a system for the clutch release bearing serves.

For sealing all position-changing components of the pressure chamber according to claim 11 and claim 12, a seal in the form of compact sealing rings provided without a press fit, both in the pressure housing and are also inserted into a groove in the piston. Alternatively offers it also looks like an entire circular surface provided compact sealing ring covering the piston.

By the measure provided in claim 13, the front on To place a diaphragm ring in front of the piston-mounted compact sealing ring, a delayed pressurization of the compact seal is advantageous reached all around. This training favors the mode of operation and the Service life of the compact sealing ring.

To further improve the seal, the claim sees 14 panels before, arranged on the pressure side immediately in front of the compact sealing rings are, whereby a direct pressurization of the sealing rings ver is avoided and thus dampened pressure impulses on the sealing rings will wear. The compact can be used to create panels Sealing ring axially offset from the pressure chamber in the piston or pressure housing be introduced and the side of the groove of the compact sealing ring offset section forming an annular gap in the piston or in the pressure housing take on the function of an aperture. The construction and the Arrangement of the compact sealing rings further provide that regardless of the axial displacement of the piston only one sealing lip of the com compact sealing ring is applied. The integrated sealing arrangement on the piston and in the pressure housing further advantageously causes one sufficient sealing against a disadvantageous air entry at one possible negative pressure in the hydraulic system, which causes the seal withstands all stresses on clutch release systems.

The compact sealing rings with a square cross are advantageous provided section profile, in which a match of the length and Width dimension of the cross section of the compact sealing ring in the installed Condition exists. Compact sealing rings of this type have a high  Seal quality on without additional measures such. B. a separately back rings used in the compact sealing ring.

According to claim 15 are as treads or sealing surfaces for the com Compact sealing rings provided for non-machined, unprocessed surfaces, on which the compact sealing rings slide, these surfaces for ver avoid corrosion to have a surface protection.

The claim 16 states that between the rigid, the pressure chamber forming components, the outer surface of the annulus on the guide tube and the pressure housing has a radially static seal, e.g. B. in the form of a O-ring, is provided. This seal is effective complete protection against possible relocation of the printing area home safe.

According to claim 17 is between the guide tube and the clutch bell a seal claimed. Alternatively, it offers itself on the outer surface of the guide tube in the axially from the pressure housing projecting section to provide a gasket or a flat seal device, which is attached to the radial section of the guide tube.

To achieve a cleaning effect on the lateral surface of the guide Pipe in the area of the clutch release bearing serves according to claim 18 multi-spline toothing on the inside of the piston. This loosens deposits on the guide tube, which are separated from the Connection to the toothing of the full cross-section of the piston when the slave cylinder is pressurized via the free end of the guide tube are pushed away.

According to claim 19, the guide sleeve is ver with a seal see that is arranged on the side facing away from the pressure housing. The seal has a sealing lip on the outer surface of the guide is guided. The sealing lip has a scraper radio tion, which advantageously a dirt entry in the guide gap between the piston and the guide tube is avoided.  

In a further embodiment of the invention is according to claim 20 an anti-rotation device between the shelf and the collar on the pressure housing and between the piston of the slave cylinder and the clutch back storage provided. This is an effective torque transmission between the outer ring of the release bearing, the piston and the Druckge created housing, which ensures that even at low temperatures and grease in the clutch release bearing of the pistons of the Slave cylinder cannot rotate with the bearing, which also causes a effective protection against seal wear can be achieved.

According to claim 21, the anti-rotation between the board and the Pressure housing designed as a gap seal, which advantageously the one dirt and dust penetrate into the area covered by the board Effectively avoids pressure housing and thus the service life of the pressure chamber Sealing, d. H. of the compact sealing ring increased.

In claim 22 it is stated that a movable snapped tether Extension of the release bearing provided on the piston or the guide sleeve with which a limited alignment of the release bearing on components the friction clutch can be ensured. The snapped Connection also results in simple, quick installation.

In a further embodiment of the inventive concept is after Claim 23 provided a self-centering spring, over which the Clutch release bearing supported on board. It is advantageous as one Sheet metal ring formed board integrally connected to the guide sleeve the, for example in the guide sleeve made of plastic poured.

To create an inseparable connection and thus preassembled Release device is according to claim 24 to the annular space of the guide tion tube attached axial disc or a radial portion of the Guide tube connected to the pressure housing by riveting. The radial rivet arranged in the pressure housing is advantageous One screw connection each for fastening the release device tung, z. B. on the gearbox.

The invention is based on the drawings and the associated figure descriptions explained in more detail. Show it:

Fig. 1 in a sectional view, the back device according to the invention in the neutral position;

Fig. 2 shows a release device according to Figure 1 in the disengaged position.

Fig. 3 shows another embodiment with a Ausrückvor direction, which in particular has a modified Kolbenab seal;

Fig. 4, the disengaging device shown in Figure 3 is combined with a release bearing;

Figure 5 shows the release device in a front view.

Fig. 6 shows the release device in the installed state.

In Figs. 1 and 2, the structure of the lockout inventive device 1 shown, wherein Fig. 1, the release bearing 2 in the neutral position, that is in the unpressurized condition shows where the Off return storage 2 is flush with the outer contour of the collar 6, the is first explained. The release device 1 then comprises essentially a release bearing 2 , a slave cylinder 3 and a guide tube 4 , which are integrated into a pressure housing 5 including all components. The pressure housing 5 is provided with a laterally arranged collar 6 in the form of a sleeve-shaped extension, in which a bore 7 and a bore 40 are made, which are guided axially through the pressure housing 5 . In a remote section of the pressure housing 7 in the direction facing away from the collar 6, a collar 13 of the guide tube 4 is fitted into the bore 40 and sealed by a sealing ring 9 . The collar 13 is designed so that there is a radial step concentrically with an axis of symmetry 10 of the Ausrückvorrich device 1 for receiving an end inserted into the guide tube 4 shaft seal ring 11th The course of the wall of the guide tube 4 is radially spaced in the area of the shaft sealing ring 11 , folded over further to form an annular annular space 8 , which partially forms the pressure space 12 for the slave cylinder 3 . The radially outer region of the guide tube 4 , namely the collar 13 , which is partially fitted into a portion of the bore 40 in the pressure housing 5 , has a radial disk 14 which bears axially on the pressure housing 5 and thus a stop for the guide tube 4th forms. A directly on the collar 13 angeord Neter, lying on the disc 14 O-ring seal 15 is used to seal the disengaging device 1 in a gear housing, not shown in Fig. 1.

A lateral surface 16 of the guide tube 4 serves to receive and guide a piston 17 of the slave cylinder 3 , on which the release bearing 2 is arranged at the end on the end facing away from the pressure chamber 12 . In order to achieve a limited radial displaceability of the clutch release bearing 2 , this is snapped onto the piston 17 by means of a spring 18 serving as a loss prevention device. An anti-rotation device 19 is used to prevent the release bearing 2 from rotating relative to the piston 17 . An axial support undergoes the release bearing 2 by a non-rotatably fixed to the piston 17 board 20 which has an annular shoulder at a radially inner and outer zone 21, and a sheet metal sleeve 22 comprises the processing in the side facing away from the clutch release bearing 2 Rich in the bore 7 and the bore 40 are performed.

The annular shoulder 22 reaching axially over the piston 17 further serves to limit the pressure chamber 12 . In order to seal all the positionally displaceable components connected to the pressure chamber 12 , both the piston 17 and the pressure housing 5 are provided with compact sealing rings 23 , 24 in the area of the guide of the sheet metal sleeve 22 , which in the direction of the pressure chamber 12 have an aperture 25 , 26 , designed as an annular gap, is assigned. The orifices 25 , 26 dampen pressure peaks before they hit the compact sealing rings 23 , 24 in the event of a sudden pressure build-up in the pressure chamber 12 through a pressure medium passed through the bore 27 into the pressure chamber 12 . To prevent rotation of the piston 17, including all related components to the pressure housing 5 , a rotation 28 serves between the annular shoulder 21 and the collar 6 of the pressure housing 5 .

Fig. 2 shows the indented position.

The design of the anti-rotation device 28 is illustrated in FIG. 2. The rim 20 covering the radial distance between the piston 17 and the inner contour of the collar 6 , including the annular shoulder 21, also has the task of protecting the pressure chamber 12 from contamination. A splined toothing 29, which is introduced on the inside in the end region on the side of the piston 17 directed towards the release bearing 2 , serves to remove impurities on the lateral surface 16 , which is released from the splined toothing 29 when the release device is actuated and is axially displaced via the guide tube 4 . Underlining the compact design, the sheet metal sleeve 22 projects into the specially designed annular space 8 on the guide tube 4 . The ring shoulder 21, however, is flush against a contact surface 30 . To achieve an inseparable connection, in particular between the guide tube 4 and the pressure housing 5 , these are connected by a plurality of hollow rivets 31 , which is provided with a bore through which the disengaging device can be fastened with screws 32 to the gear housing.

In a second exemplary embodiment ( FIGS. 3 and 4) of a release device according to the invention, the components which correspond to the first exemplary embodiment in terms of structure and function are provided with the same reference numerals, so that reference can be made to the description of the first exemplary embodiment with regard to their description.

The piston 17 a shown in FIGS. 3 and 4 has a structure and seal which differ from FIGS. 1 and 2. The sheet metal sleeve 22 a which surrounds the piston 17 a radially also protrudes axially beyond the contour of the piston 17 a into the pressure chamber 12 , but is provided on the opposite side with a radially inwardly directed flange 45 which is cast into the piston 17 a. For the piston seal, a compact sealing ring 23 a is provided, which bridges the radial distance between the guide tube and the sheet metal sleeve 22 a and which abuts the piston 17 a on the end face. To achieve an advantageous delayed pressurization of the compact sealing ring 23 a this is an aperture ring 41 upstream. To stiffen the guide tube 4 a and to form an end stop for the piston 17 a, a bush 44 is used , which is inserted into the release bearing 2 a adjacent end of the guide tube 4 a.

Another difference over the design according to FIGS. 1 and 2 consists in the design of the guide tube 4 a in the area of the annular space 8 . A guide sleeve 42 is provided in the transition region of the guide tube 4 a to the pressure housing 5 a in order to achieve an improved seal and a simpler assembly. The guide sleeve 42 fitted into a bore of the pressure housing 5 a and sealed with a sealing ring 9 extends axially out of the pressure housing 5 a as far as the end of the annular space 8 . To seal the disengaging device 1 a in the direction of the clutch bell 35 (see Fig. 6), a flat seal 43 is provided, which is arranged abutting the outer surface 13 on the radial portion of the guide tube 4 .

In Fig. 4, the clutch release bearing 2 a is shown in the neutral position, comparable to FIG. 1. The piston 17 a is stepped at its end facing the bush 44 to form a snug fit 49 on which a guide sleeve 48 is rotatably guided, which leads to Includes the clutch release bearing 2 a. Due to the axial force of the spring 18 , the clutch release bearing 2 a is non-positively on the board 20 a of the guide sleeve 48 . The rim 20 a in the radial outer region merges into an annular shoulder 21 a arranged at right angles thereto, which can be displaced at a distance from the collar 6 together with the clutch release bearing 2 a in the bore 7 . To avoid the entry of dirt between the piston 17 a and the raceway 16 in the region of the guide 47 , a seal 46 is arranged on the end of the piston 17 a pointing in the direction of the bush 44 , which also removes dirt on the guide tube when the clutch is actuated.

To achieve a better alignment of the release bearing 2 a on board 20 a is a self-centering spring 50 which is used between the release bearing 2 a and the board 20 a.

Fig. 5 shows the front view of the disengaging device 1 accordingly the arrow direction A of Fig. 1. It shows a possible outer design of the pressure housing 5 with a largely cylindrical collar 6 and an adjoining triangular section. The collar 6 has two radially outward protection against rotation 28 in the form of outwardly stepped sections, in which the same shaped sections of the annular shoulder 21 are fitted. To achieve an axial securing of the annular shoulder 21 and the associated clutch release bearing 2 , an axial stop 34 in the form of an externally inserted into the collar 6 in the area of an anti-rotation pin 28 is used . Each triangular section is provided with a previously mentioned rivet 31 . In the loading area of the triangular section of the pressure housing 5 , a pressure port 33 is further provided locally, to which a pressure line can be connected and which is provided with a centrally arranged bore 27 (see FIG. 1), from which pressure medium into the pressure chamber of the release device 1 can occur to act on the slave cylinder with which an axial displacement of the release bearing 2 can be reached bar.

Fig. 6 shows the release device 1 in the installed state. The gear shaft 36 protrudes into the clutch bell 35 . Axially offset at the end to the roller bearing 39 , coaxially to the gear shaft 36 , the release device 1 is arranged and thereby bridges the axial distance between the gear housing wall in the region of the roller bearing 39 and a friction clutch 37 , which is connected to an internal combustion engine not shown in FIG . The release bearing 2 is independent of the switch position of the clutch 1-positively to a clutch release lever 38 of the friction clutch 37 on to solve either the friction clutch 37 (see neutral position of the release bearing 2) indent 37 or the friction clutch (see release position of the release bearing 2).

Reference list

1

,

1

a release device

2nd

,

2nd

a release bearing

3rd

Slave cylinder

4th

,

4th

a guide tube

5

,

5

a pressure housing

6

collar

7

drilling

8th

Annulus

9

Sealing ring

10th

Radial stage

11

Shaft seal

12th

,

12th

a pressure room

13

collar

14

disc

15

O-ring

16

Lateral surface

17th

,

17th

a piston

18th

feather

19th

Anti-rotation device

20th

,

20th

a board

21

,

21

a ring shoulder

22

,

22

a sheet metal sleeve

23

,

23

a compact sealing ring

24th

Compact sealing ring

25th

cover

26

cover

27

drilling

28

Anti-rotation device

29

Multiple splines

30th

Contact surface

31

Hollow rivet

32

screw

33

Discharge nozzle

34

Axial stop

35

Clutch bell

36

Gear shaft

37

Friction clutch

38

Release cable

39

roller bearing

40

drilling

41

Aperture ring

42

Guide sleeve

43

Flat gasket

44

Rifle

45

Flanging

46

poetry

47

guide

48

Guide sleeve

49

Fit

50

Self centering spring

Claims (24)

1.Hydraulic actuation system for a friction clutch in a vehicle with a disengaging device which has a pressure housing concentrically surrounding a drive shaft and which can be fixed to the transmission housing or to a clutch bell, in the bore of which a guide tube is inserted to form a slave cylinder having an annular cross section, one of which is its end with a piston connected from the back bearing is sealingly guided between the guide sleeve and the slave cylinder, characterized in that the piston ( 17 , 17 a) is provided with a sheet metal sleeve ( 22 , 22 a) at least partially enclosing its outer surface, which is provided with one of the release bearing ( 2 , 2 a) facing away from the end of the piston ( 17 , 17 a) protrudes axially and is sealingly guided in the bore ( 40 ). 2. Hydraulic actuation system according to claim 1, characterized in that in a neutral position of the disengaging device ( 1 , 1 a) the axial extension of the guide tube ( 4 , 4 a) corresponds to the width of the disengaging device ( 1 , 1 a). 3. Hydraulic actuation system according to claim 2, characterized in that a shaft sealing ring ( 11 ) is provided at the end of the guide tube ( 4 , 4 a) facing away from the release bearing ( 2 , 2 a) in a radial step ( 10 ). 4. Hydraulic actuation system according to one of the preceding claims, characterized in that a chipless shaped guide tube ( 4 , 4 a) is used, which has an annular space ( 8 ) at one end, formed by a white send in the radial and axial direction , Collar ( 13 ) produced by flanging, the annular space ( 8 ) being part of a pressure space ( 12 ) and a further part of the pressure space ( 12 ) comprising the pressure housing ( 5 ), the sheet metal sleeve ( 22 ), an annular piston surface of the Piston ( 17 ) and a cylindrical outer surface ( 16 ) of the guide tube ( 4 ) is limited ( Fig. 1 and 2). 5. Hydraulic actuation system according to claim 4, characterized in that the collar ( 13 ) merges into a flange on the end face on the pressure housing ( 5 a), and that in the pressure chamber ( 12 a) in a transition region between the pressure housing ( 5 a) and a guide sleeve ( 42 ) is fitted to the flange ( Fig. 3). 6. Hydraulic actuation system according to claim 1, characterized in that the piston ( 17 a) has an aperture ring ( 41 ) in front. 7. Hydraulic actuation system according to claim 5, characterized in that the sheet metal sleeve ( 22 a) has a material of the piston ( 17 a) overmolded or encapsulated flange ( 45 ) ( Fig. 3 and 4). 8. Hydraulic actuation system according to claim 4, characterized in that a radial disc ( 14 ) on the collar ( 13 ) is permanently attached ( Fig. 1 and 2). 9. Hydraulic actuation system according to claim 1, characterized in that in an outer annular groove of the piston ( 17 ) a rim ( 20 ) of the sheet metal sleeve ( 22 ) is rotated and fixed in position, on the end face of which the clutch release bearing ( 2 ) is axially supported, the rim ( 20 ) being provided with an annular shoulder ( 21 ) on a radial outer zone, the annular shoulder ( 21 ) on an axially projecting collar ( 6 ) of the pressure housing ( 5 ) and the sheet metal sleeve ( 22 ) in the bore ( 40 ) of the pressure housing ( 5 ) are guided ( Fig. 1 and 2). 10. Hydraulic actuation system according to claim 1, characterized in that the piston ( 17 a) has a stepped portion for receiving a guide sleeve ( 48 ) on which a radially extending support disc ( 51 ) is fixed, with this support disc made of sheet metal (51) the clutch release bearing (2 a) federkraftbeauf strike is applied (Fig. 4). 11. Hydraulic actuation system according to one of claims 4 to 7, characterized in that for sealing all position-changing components of the pressure chamber ( 12 , 12 a) serve compact sealing rings ( 23 , 23 a, 24 ) which in the pressure housing ( 5 , 5 a) or in the piston ( 17 , 17 a) are used. 12. Hydraulic actuation system according to claim 11, characterized in that for sealing the piston ( 17 a) a compact sealing ring ( 23 a) is used, the end face in the direction of the pressure chamber ( 12 ) pointing to the piston ( 17 a) and thereby attached radial distance between the sheet metal sleeve ( 22 a) and the guide tube ( 4 a) bridges ( Fig. 3 and 4). 13. Hydraulic actuation system according to claim 12, characterized in that the compact sealing ring ( 23 a) has an aperture ring ( 41 ) is mounted in front ( Fig. 3 and 4). 14. Hydraulic actuation system according to claim 11, characterized in that on one side facing the pressure chamber ( 12 ) the compact sealing ring ( 23 , 24 ) is assigned an aperture ( 25 , 26 ) ( Fig. 1 and 2). 15. Hydraulic actuation system according to claim 11 or 12, characterized in that the compact sealing rings ( 23 , 23 a, 24 ) on non-machined, unprocessed running surfaces of the guide tube ( 4 , 4 a) and the sheet metal sleeve ( 22 , 22 a) slide. 16. Hydraulic actuation system according to claim 4 or 5, characterized in that to achieve a radially static seal between the pressure housing ( 5 , 5 a) and the guide tube ( 4 , 4 a) a sealing ring ( 9 ) between the collar ( 13 ) or the guide sleeve ( 42 ) and the pressure housing ( 5 , 5 a) is provided. 17. Hydraulic actuation system according to claim 1, characterized in that between the guide tube ( 4 , 4 a) and the clutch bell ( 35 ) an O-ring ( 15 ) or a flat seal ( 43 ) is seen before. 18. Hydraulic actuation system according to claim 1, characterized in that on the release bearing ( 2 ) directed end of the piston ( 17 ) on its inside has a spline ( 29 ). 19. Hydraulic actuation system according to claim 10, characterized in that the guide sleeve ( 48 ) is provided with a seal ( 46 ) which is arranged on the side facing away from the pressure housing ( 5 a) and sealingly on the circumference of the guide tube ( 4th a) creates ( Fig. 4). 20. Hydraulic actuation system according to claim 1 and 9, characterized in that an anti-rotation device ( 19 , 28 ) between the components board ( 20 ) and collar ( 6 ) and between the piston ( 17 ) and release bearing ( 2 ) is provided. 21. Hydraulic actuation system according to claim 20, characterized in that the anti-rotation device ( 28 ) between the board ( 20 ) and the collar ( 6 ) is designed as a gap seal to protect the compact sealing ring ( 24 ). 22. Hydraulic actuation system according to claim 1, characterized in that a movable, snapped connection of the release bearing ( 2 , 2 a) on the piston ( 17 , 17 a) or the guide sleeve ( 48 ) is seen before ( Fig. 1 and 4th ). 23. A hydraulic actuation system as claimed in claim 10, characterized in that the clutch release bearing (2 a) a Selbstzentrierungs is spring (50) is assigned, via which the clutch release bearing (2 a) is present (Fig. 4) on the board (20 a). 24. Hydraulic actuation system according to claim 1, characterized in that a hollow rivet ( 31 ) to achieve an insoluble connection Ver the pressure housing ( 5 , 5 a) with the guide tube ( 4 a) or with the washer on the guide tube ( 4 ) ( 14 ) is provided and for fastening the disengaging device ( 1 , 1 a) a screw connection ( 32 ) guided through the hollow rivet ( 31 ) is used ( FIGS. 1 and 4).