CN111433476A

CN111433476A - Slave cylinder with height-adjustable piston and clutch with slave cylinder

Info

Publication number: CN111433476A
Application number: CN201880074232.8A
Authority: CN
Inventors: 托马斯·尼森; 曼纽尔·巴斯勒; 菲利普·瓦格纳; 弗拉迪米尔·沙林
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2017-11-15
Filing date: 2018-11-12
Publication date: 2020-07-17
Anticipated expiration: 2038-11-12
Also published as: CN111433476B; DE112018005699A5; DE102017126870A1; WO2019096350A1

Abstract

The invention relates to a slave cylinder (1) for actuating a clutch (2) or a brake of a motor vehicle, having a housing (3) and a piston (4) which is arranged axially displaceably in the housing (3) and which is designed to displace an actuating bearing (5) when axially displaced relative to the housing (3) in order to actuate the clutch (2) or the brake, wherein the piston (4) is designed in terms of construction and/or material such that it occupies one of different predetermined axial lengths depending on its setting for operation. The invention also relates to a clutch (2) for a motor vehicle having such a slave cylinder (1).

Description

Slave cylinder with height-adjustable piston and clutch with slave cylinder

Technical Field

The invention relates to a slave cylinder for actuating a clutch or a brake of a motor vehicle, having a housing and a piston which is arranged axially displaceably in the housing and is designed to displace an actuating bearing when axially displaced relative to the housing in order to actuate the clutch or the brake. The invention further relates to a clutch for a motor vehicle having such a slave cylinder.

Background

Clutch slave cylinders are already known in the prior art. For example, EP 2739870B 1 discloses a release system for actuating a clutch, which release system is of the type of a slave cylinder (CSC, concentric/clutch slave cylinder) and has at least one first piston which is movable in a housing along a longitudinal axis, the end of which, which is directed toward a first pressure chamber, has a first seal, and the region of which, which is opposite the seal, acts on a first, radially outer coupling bearing, wherein, in order to prevent a stationary first bearing ring of the first coupling bearing from rotating in order to support a drag torque caused by the first coupling bearing, at least one energy storage element is integrated in the slave cylinder, which element counteracts the drag torque by a tangential support torque (torque).

However, the prior art always has the following disadvantages: washers are used in conventional slave cylinders to bridge the tolerances between the slave cylinder and the clutch. Since the slave cylinder and the clutch have to be measured separately in order to compensate for the spacing and this spacing may vary strongly, it is necessary to provide washers/shims (shim discs) of sufficiently different thicknesses corresponding to the respective diameters of the bearing surfaces on the bearings in order to counteract the spacing. Thereby requiring many additional fittings and making assembly difficult.

Disclosure of Invention

It is therefore an object of the present invention to avoid or at least reduce the disadvantages of the prior art. In particular, a slave cylinder is to be provided which can be assembled particularly simply, has few fittings and can therefore be produced at low cost.

According to the invention, the object is achieved in a device of this type in that the piston is designed structurally and/or materially in such a way that it assumes one of different predetermined axial lengths, i.e. heights, depending on its setting for operation. In other words, the piston is designed such that it is height-adjustable, i.e. its axial length is adjustable.

This has the advantage that the number of fittings is reduced by replacing the extra washers by the piston itself.

Advantageous embodiments are claimed in the dependent claims and are explained in more detail below.

It is furthermore advantageous if the piston has an upper piston part and a lower piston part, which is formed separately from the upper piston part, for example, and which can be displaced relative to one another in the axial direction in order to be fixed relative to one another in at least one setting. Thus, the piston may set/adjust its overall axial length by displacing its constituent parts relative to each other.

It is also advantageous if the upper piston part can be arranged in a predetermined position at different axial distances from the lower piston part. Thus, depending on the setting of the piston, it is in one of the predetermined positions, for example in the minimum position, the intermediate position or the maximum position, in which positions the piston constitutes a different axial length for operation.

It is also advantageous if the lower piston part has at least one bearing surface which is designed such that a corresponding bearing surface of the upper piston part rests against the bearing surface in order to transmit forces in the axial direction, wherein the upper piston part has a plurality of corresponding bearing surfaces which are arranged offset from one another in the axial direction. The different counter bearing surfaces are thus arranged in different planes in the axial direction, so that the overall length of the piston can be influenced or set depending on which counter bearing surface abuts against the bearing surface. The distance between the outer axial end sides of the piston upper part and the piston lower part facing away from each other is thereby changed.

It is also expedient for the position to be settable by rotating the upper piston part relative to the lower piston part. It is particularly advantageous if the upper piston part can be brought into an adjustment position in which a rotation of the upper piston part relative to the lower piston part is possible. It is then advantageous, on the contrary, to prevent the piston upper part from rotating relative to the piston lower part in any position other than the adjustment position.

It is also advantageous if, between adjacent corresponding bearing surfaces of different axial height, a wall projecting in the axial direction is formed in the form of a rib in the circumferential direction, which wall is designed to support the drag torque when interacting with a flank arranged perpendicularly to the circumferential direction at the lower part of the piston.

Furthermore, it is advantageous if fastening hooks are formed on the upper piston part, which fastening hooks are designed such that, when the position is set, they maintain contact between the upper piston part and the lower piston part. The securing hook thus advantageously acts as a loss prevention device.

It is also advantageous if the fixing hook enables or guides a rotation between the upper piston part and the lower piston part, for example in the adjustment position. Thereby simplifying the setting of the position.

Furthermore, it is advantageous if an adjustment guide is formed on the lower piston part, which guide is designed to guide the rotation of the upper piston part relative to the lower piston part. It is particularly advantageous if the adjustment guide is designed as a circumferential groove which, for example, cooperates with the fastening hook, for example, as a thickening on the fastening hook, for guiding the relative rotation.

It is also advantageous if at least one position marking for each position of different axial height is present at the upper part of the piston. Thus enabling setting of the desired position.

It is also expedient if at the lower part of the piston there is at least one locking part which is designed to indicate the position of the bearing surface in the circumferential direction. This simplifies the setting of the position in a simple manner.

It is particularly expedient if, when there are a plurality of bearing surfaces, a latching portion is present for each bearing surface. It is also preferred that the arrangement of the latching section is matched to the arrangement of the position markings, so that in each of the predetermined positions the latching section is arranged at the same height in the circumferential direction as one of the position markings.

It is also advantageous if the outer diameter of the lower part of the piston increases up to the adjustment guide. Thus, an axial force is applied to the upper piston part, which presses the upper piston part towards the lower piston part. In this case, the lower part of the piston preferably has a conical section.

The object of the invention is also achieved according to the invention by a clutch for a motor vehicle having a slave cylinder according to the invention.

In other words, the invention relates to a slave cylinder with a piston (shim piston) which is height-adjustable in the axial direction, wherein shim discs/washers can be dispensed with. The invention is intended for the field of use of slave cylinders (CSC, Clutch slave cylinder) or double slave cylinders (DCSC, double Clutch slave cylinder). The conventional piston of the slave cylinder is therefore replaced by a height-adjustable piston which transmits the force for opening or closing the clutch via a corresponding bearing/actuating bearing. Assembly is simplified and the number of additional fittings is reduced by eliminating shim discs/washers, which correspond to the respective diameters of the bearing surfaces on the bearings and which, in conventional pistons, bridge the tolerances between the CSC/DCSC and the clutch to be actuated. In order to be able to compensate for the different spacing of each slave cylinder-clutch pair, the slave cylinder and the clutch must be measured separately. The spacing between the bearing surface of the bearing and the clutch can then be determined. Since the spacing can vary widely, it is necessary to provide a sufficient number of shim discs of different thicknesses to compensate for the spacing. According to the invention, the height adjustment means are integrated in the piston such that the piston can be locked/set to different height levels/axial heights by rotating the variable upper part/piston upper part of the piston. The height of the individual pistons in the slave cylinders can be adjusted by the customer in the field.

The forces occurring during the actuation of the clutch are supported via the bearing surfaces. The drag torque is absorbed via the wall of each step. In order to be able to easily find or set the position of the bearing surfaces, a locking device for each bearing surface is mounted on the outer edge of the lower part of the piston. In the illustrated embodiment, the piston can be moved into four different positions. Three of which are fixed and one for the adjustability of the upper part of the piston. In the adjusting position, the fixing hook/fixing clip of the upper piston part is placed in the adjusting guide at the lower piston part.

The piston/shim piston according to the invention consists of a total of two parts, wherein the upper variable part/piston upper part is supported on its bearing surface in such a way that it rests on the lower part/piston lower part. The lower portion is disposed in the housing with the seal. The corresponding height can be set by means of a bearing surface/step at the upper part of the shim piston. Depending on the implementation, the number, height and shape of the steps may be varied. At the outer edge of the upper part of the piston there are fixing hooks which ensure that the two parts are linked together during transport. The shape is designed such that the fixing hook fits exactly into the adjustment guide. This determines the position in which the upper piston part can be rotated and the desired step can be set. The outer diameter of the hook becomes larger toward the adjustment guide. The upper piston part is thus pressed against the bearing surface at a higher step. The position marking and locking device enables the upper piston part to be positioned precisely on the lower piston part.

Drawings

The invention is explained below with the aid of the figures. The figures show:

figure 1 shows a longitudinal section through a slave cylinder with a height-adjustable piston,

fig. 2 shows an enlarged view of a part of fig. 1.

Figure 3 shows a longitudinal section of the slave cylinder,

figure 4 shows a perspective view of the lower part of the piston,

figure 5 shows a perspective view of the upper part of the piston,

figures 6 and 7 show perspective views of the piston,

figures 8 to 11 show longitudinal sectional views of the piston in different positions,

FIG. 12 shows an enlarged view of a portion of FIG. 9, an

Fig. 13 to 20 show further views of the piston, of the upper part of the piston and of the lower part of the piston.

The figures are merely schematic and are used only for the understanding of the present invention. Like elements have like reference numerals.

Detailed Description

Fig. 1 to 3 show a slave cylinder 1 for actuating a clutch 2 of a motor vehicle. The slave cylinder 1 has a housing 3 in which a piston 4 is arranged so as to be axially displaceable. When the piston 4 is moved axially relative to the housing 3, the actuating bearing 5 for actuating the clutch 2 is displaced. The piston 4 is designed in terms of construction and/or material such that it can occupy different predetermined axial lengths.

When the actuating bearing 5 is disengaged, the pressure pot 6 is displaced in the axial direction, so that the clutch discs 7 of the clutch 2, which are friction clutches 8, are pressed together, so that torque is transmitted in a force-fitting manner. In the embodiment shown, there is a second slave cylinder 9, which is arranged concentrically to the slave cylinder 1 according to the invention. The second slave cylinder 9 is designed as a conventional slave cylinder, the piston 10 of which is not height-adjustable. In order to be able to set different axial heights, a washer 11 (shim plate) is used, which is arranged between the second actuating bearing 12 and the second pressure tank 13.

The piston 4 of the slave cylinder 1 according to the invention is constructed such that its axial length/height can be varied. The piston 4 has an upper piston part 14 and a lower piston part 15, wherein the upper piston part 14 and the lower piston part 15 can be set at a distance from one another.

Fig. 4 shows the lower piston part 15 with an annular body 16. On the axial end side of the piston lower part 15, three bearing surfaces 17 for the piston upper part 14 are formed, which project in the axial direction and are arranged at regular intervals around the circumference of the body 16. The bearing surface 17 is arranged in a plane perpendicular to the axial direction. The bearing surface 17 has the shape of a ring segment in cross section, and the side 18 of the bearing surface 17 is oriented perpendicular to the axial direction of the piston lower part 15. Three locking portions 19 are formed on the outer diameter of the piston lower part 15, which are arranged in the circumferential direction at the level of the three bearing surfaces 17. The locking part 19 is formed as two parallel webs 20 which project in the radial direction and are oriented in the axial direction.

Fig. 5 shows the piston upper part 14, which has an annular plate-shaped body 21. On the axial end side 22 of the piston upper part 14 facing the piston lower part, nine ring-segment-shaped counter-bearing surfaces 23 are formed, which are arranged so as to be distributed uniformly over the circumference of the main body 21. The corresponding bearing surface 23 protrudes in the axial direction. The three corresponding bearing surfaces 23 are each arranged in a plane arranged perpendicular to the axial direction, wherein the planes are offset from one another in the axial direction. This means that three first counter-bearing surfaces 24 are arranged in a first plane, three second counter-bearing surfaces 25 are arranged in a second plane, and three third counter-bearing surfaces 26 are arranged in a third plane, wherein the first plane has the largest spacing, the second plane has the second largest spacing, and the third plane has the third largest (i.e. smallest) spacing in the axial direction from the axial end side 27 of the piston upper part 14 facing away from the piston lower part. The first, second and third counter bearing surfaces 24, 25, 26 are each arranged at regular intervals in the circumferential direction, wherein the intervals each correspond to the intervals in the circumferential direction of the bearing surfaces 17 at the piston lower part 15. Between two corresponding bearing surfaces 23 which are adjacent in the circumferential direction, in each case a wall 28 in the form of a rib 29 which projects in the axial direction and is oriented in the radial direction is formed for supporting the drag torque.

On the piston upper part 14, a circumferential collar 30 is formed which projects in the axial direction from the end face 22 facing the piston lower part. Nine fixing hooks 31 uniformly distributed in the circumferential direction project from the flange 30 in the axial direction. The fastening hook 31 therefore has a thickening 32 at its axial end facing the lower piston part. A positioning mark 33 is provided on the radially outer side of each fixing hook 31. Each of the position marks 33 is arranged at the same height in the circumferential direction as one of the first, second and third corresponding bearing surfaces 24, 25, 26. In the exemplary embodiment shown, the position markers 33 are triangular in configuration. The fastening hook 31 is therefore adapted to the latching portion 19 of the piston lower part 15, so that the width of the fastening hook 31 is smaller than the distance between the two parallel webs 20 of the latching portion 19.

Fig. 6 and 7 show a piston 4 with a lower piston part 15 and an upper piston part 14. The piston upper part 14 is arranged with its axial end side 22 facing the piston lower part, on which a bearing surface 17 is formed, on the axial end side of the piston lower part 15. The upper piston part 14 is positioned on the lower piston part 15 in such a way that the first counter bearing surface 24 or the second counter bearing surface 25 or the third counter bearing surface 26 rests on the bearing surface 17 of the lower piston part 15. By the first, second and third corresponding bearing surfaces 24, 25, 26 being arranged in planes offset from each other in the axial direction, the axial length of the piston 4 varies depending on the position of the piston upper part 14 relative to the piston lower part 15 (i.e. which corresponding bearing surface 23 is located). The drag torque can be supported via the wall 28 of the upper piston part 14 and the side 18 of the lower piston part 15.

In the piston lower part 14, an adjustment guide 34 is provided, which is designed as a continuously encircling groove 35. The position of the piston upper part 14 relative to the piston lower part 15 can be set by bringing the piston upper part 14 into an adjustment position in which the thickened portion 32 of the fixing hook 31 engages into the adjustment guide 34; in the adjusting position, the upper piston part 14 can be rotated relative to the lower piston part 15. The thickened portion 32 also serves as a loss prevention means. The outer diameter of the lower piston part 15 increases in the axial direction via the ramp 36 toward the adjustment guide 34, so that an axial force is exerted in cooperation with the securing hook 31, which axial force presses the upper piston part 14 against the lower piston part 15.

Fig. 8 to 11 show different positions of the upper piston part 14 relative to the lower piston part 15. In fig. 8, the third corresponding bearing surface 26 is seated on the bearing surface 17 such that the piston 4 is in a minimum position/setting and has a minimum axial length. In fig. 9, the second corresponding bearing surface 25 is seated on the bearing surface 17 such that the piston 4 is in a medium position/setting and has a medium axial length. In fig. 10, the first corresponding bearing surface 24 is seated on the bearing surface 17 such that the piston 4 is in the maximum position/setting and has the maximum axial length. In fig. 11, the thickening 32 on the fixing hook 31 is located in the adjustment guide so that the piston 4 is in the adjustment position and the piston upper part 14 is rotatable relative to the piston lower part 15 in order to set the minimum position, the intermediate position and the maximum position.

Fig. 12 shows an enlarged view of the upper piston part 14 and the lower piston part 15. Fig. 13 to 15 show further views of the piston 4. Fig. 16 and 17 show further views of the lower piston part 15 and fig. 18 to 20 show further views of the upper piston part 14.

List of reference numerals

1 slave cylinder

2 Clutch

3 case

4 piston

5 operating bearing

6 pressure tank

7 clutch disc

8 friction clutch

9 second slave cylinder

10 piston

11 gasket

12 second steering bearing

13 second pressure tank

14 upper part of piston

15 lower part of piston

16 main body

17 bearing surface

18 side surface

19 locking part

20 contact piece

21 main body

22 axial end side

23 corresponding to the bearing surface

24 first counter bearing surface

25 second corresponding bearing surface

26 third corresponding bearing surface

27 axial end side

28 wall section

29 Rib

30 flange

31 fixed hook

32 thickened part

33 position mark

34 adjustment guide

35 groove

36 inclined plane

Claims

1. A slave cylinder (1) for actuating a clutch (2) or a brake of a motor vehicle, having a housing (3) and a piston (4) which is arranged axially displaceably in the housing (3) and which is designed for displacing an actuating bearing (5) upon axial displacement relative to the housing (3) in order to actuate the clutch (2) or the brake, characterized in that the piston (4) is designed structurally and/or materially such that it occupies one of different predetermined axial lengths depending on its setting for operation.

2. The slave cylinder (1) according to claim 1, characterised in that the piston (4) has an upper piston part (14) and a lower piston part (15) which are displaceable relative to each other in the axial direction in order to be fixed to each other in at least one setting.

3. The slave cylinder (1) according to claim 2, characterized in that the upper piston part (14) can be arranged in a predetermined position with different axial distances from the lower piston part (15).

4. The slave cylinder (1) according to claim 2 or 3, characterized in that the lower piston part (15) has at least one bearing surface (17) which is designed such that a corresponding bearing surface (23, 24, 25, 26) of the upper piston part (14) bears against it for axial transmission of force, wherein the upper piston part (14) has a plurality of corresponding bearing surfaces (23, 24, 25, 26) which are arranged offset from one another in the axial direction.

5. The slave cylinder (1) according to any one of claims 2 to 4, characterized in that the position can be set by rotating the piston upper part (14) relative to the piston lower part (15).

6. The slave cylinder (1) according to one of claims 3 to 5, characterised in that fixing hooks (31) are formed at the piston upper part (14), which fixing hooks are designed such that, when adjusting the position, they maintain contact between the piston upper part (14) and the piston lower part (15).

7. The slave cylinder (1) according to one of claims 2 to 6, characterized in that an adjustment guide (34) is formed at the piston lower part (15), which adjustment guide is designed for guiding a rotation of the piston upper part (14) relative to the piston lower part (15).

8. The slave cylinder (1) according to any one of claims 3 to 7, characterised in that at least one position marking (33) is present at the piston upper part (14) for each position of different axial height.

9. The slave cylinder (1) according to one of claims 2 to 8, characterized in that at the piston lower part (15) there is at least one locking portion (19) which is designed to indicate the position of the bearing surface (17) in the circumferential direction.

10. A clutch (2) for a motor vehicle having a slave cylinder (1) according to any of claims 1 to 9.