CN112639322B

CN112639322B - Slave cylinder with exhaust on housing

Info

Publication number: CN112639322B
Application number: CN201980055483.6A
Authority: CN
Inventors: D·M·罗伊特; S·奥特曼; P·奥博勒
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2018-08-23
Filing date: 2019-08-02
Publication date: 2022-10-25
Anticipated expiration: 2039-08-02
Also published as: WO2020038524A1; CN112639322A; DE102018120581A1; DE112019004203A5

Abstract

The invention relates to a slave cylinder (1) for a clutch actuating device of a motor vehicle, comprising a housing (2) and a piston (4) which is accommodated in the housing (2) such that it can move and delimits a pressure chamber (3) together with the housing (2), wherein the piston (4) comprises a seal (5) which abuts against the housing (2) within a displacement path of the piston (4) in order to seal the pressure chamber (3) from the surroundings of the housing (2), wherein the seal (5) is located on a ventilation recess (6) of the housing (2) in at least one ventilation position of the piston (4) adjacent to the displacement path in such a way that the pressure chamber (3) is open to the surroundings. The invention also relates to a clutch actuating device having the slave cylinder (1); and to a clutch system.

Description

Slave cylinder with exhaust on housing

Technical Field

The invention relates to a hydraulic slave cylinder for a clutch actuation device of a motor vehicle, such as a passenger vehicle, a lorry, a bus or another commercial vehicle, having a housing and a piston which is accommodated displaceably in the housing and which delimits a pressure chamber together with the housing, wherein the piston has a seal which sealingly/tightly abuts against the housing within the path of displacement of the piston in order to seal the pressure chamber from the surroundings of the housing. The invention also relates to a clutch actuating device having such a slave cylinder. The invention further relates to a clutch system.

Background

In order to ensure a reliable function of the clutch actuation device and thus of the slave cylinder, an exhaust system is provided in the known clutch system. Such a venting solution is usually provided in the master cylinder of the clutch actuating device, for example in WO 2011/072641 A2.

However, the clutch actuation device has the disadvantage that in the final installed state, the slave cylinder must always be arranged lower than the master cylinder with respect to the applied gravitational field. Increasingly, however, the slave cylinder is arranged above the master cylinder with respect to the acting gravitational field. The setting thus results in: air accumulates in the slave cylinder and can cause malfunctions when the clutch is actuated.

Disclosure of Invention

The object of the present invention is therefore to eliminate the disadvantages known from the prior art and in particular to provide a slave cylinder which enables reliable venting of a clutch actuating system, wherein a seal is established on a venting recess of the housing in at least one venting position of the piston adjacent to the displacement path, so that the pressure chamber is open to the surroundings. That venting recess is provided on a specific/limited circumferential area of the housing.

In this way, a reliable function of the clutch actuation device is ensured for the case in which the slave cylinder is arranged at a higher level than the master cylinder.

The dependent claims protect further advantageous embodiments and are further elaborated below.

It is therefore advantageous if the venting recess is arranged at the highest point of the pressure chamber/housing, which delimits the pressure chamber radially to the outside, with respect to the intended motor vehicle-side installation state of the slave cylinder and/or alternatively with respect to the applied gravitational field. This makes it possible to achieve particularly effective venting.

It is furthermore advantageous if the venting recess has a longitudinal extension in the direction of movement of the piston and is realized with a defined width and/or depth. The cross section of the venting recess can thereby be adjusted in a defined manner in accordance with the existing pump volume and the set dynamic pressure. Furthermore, the length of the venting recess and thus the overall geometry can be adjusted individually.

If the venting recess is realized in a radially (locally) thickened portion of the housing, the strength of the housing is significantly less weakened or even not weakened via the venting recess. The radial thickening is formed only over a partial section of the circumferential/limited circumferential region of the housing. The thickened portion projects in said limited circumferential region from the generally circular extension of the housing (along an imaginary circumferential line around the longitudinal axis) inwards in a radial direction.

The manufacturing effort is further reduced if the housing is made of plastic.

In this case, the venting recesses can also be formed in the prototype technology (preferably directly during the casting of the housing). Instead of the prototype technique of forming the venting recesses, they can also be realized in a cut-out manner (as drilled or milled portions).

The housing is particularly stable if it is made of metal.

With regard to the metallic construction of the housing, it is also advantageous if the venting recesses are produced by embossing.

The invention further relates to a clutch actuation device for a drive train of a motor vehicle, having a hydraulic slave cylinder according to the invention and a master cylinder which is hydraulically coupled or couplable to the slave cylinder, according to at least one of the embodiments described above.

The invention also relates to a clutch system for a drive train of a motor vehicle, having a clutch and a clutch actuation device operatively connected to the clutch.

In other words, according to the invention, the venting opening (venting recess) is realized in the slave cylinder pressure chamber (pressure chamber). For the venting of the hydraulic system, a venting groove (venting recess) is therefore integrated into the pressure chamber of the slave cylinder.

The present invention may also include a drive train having a hydraulic slave cylinder, wherein the slave cylinder may have one or more of the features described above.

In particular, the venting recess can be arranged at the highest point of the pressure chamber/housing, which bounds the pressure chamber radially to the outside, with respect to the installed state of the slave cylinder in the drive train and also with respect to the applied gravitational field. This makes it possible to achieve particularly effective venting.

Drawings

The invention will now be explained in more detail below with reference to different embodiments according to the accompanying drawings.

The figures show:

fig. 1 shows a longitudinal section through a slave cylinder according to a first embodiment of the invention, with the piston of the slave cylinder in the extended position,

fig. 2 shows a longitudinal section of the slave cylinder, similar to fig. 1, with the piston in the venting position, in which venting of the piston chamber to the surroundings can take place past a seal on the piston,

figure 3 shows a front view of the housing of the slave cylinder used in figures 1 and 2,

figure 4 shows a detail view of the circumferential region of the housing indicated by "IV" in figure 3,

fig. 5 shows a detailed longitudinal section of the housing according to fig. 3 and 4, for illustrating the venting recess,

FIG. 6 shows a longitudinal section through a slave cylinder according to a second embodiment of the invention, in which the housing is no longer formed of plastic but of metal, in contrast to the first embodiment, and

fig. 7 shows a perspective view of the housing used in fig. 6, cut open in the region of the venting recess in the longitudinal direction.

The drawings are merely schematic representations, which are only used for an understanding of the present invention. Like elements are provided with like reference numerals. The different features of the different embodiments can also be freely combined with each other.

Detailed Description

The principle configuration of a slave cylinder 1 according to a first embodiment of the present invention is illustrated in fig. 1. The hydraulic slave cylinder 1 is used in a typical manner for a clutch operating device of a clutch system during its operation. In addition to the slave cylinder 1, the clutch actuation device has a master cylinder, which is not shown here for the sake of clarity, coupled to the slave cylinder 1, i.e. to the pressure chamber 3 of the slave cylinder 1, via a hydraulic path. During operation of the clutch actuation device, the slave cylinder 1 is normally actuated with a pressure build-up on the master cylinder side. The slave cylinder 1 has a regulating effect on a clutch, such as a friction clutch, of a clutch system. Clutches are also used in a known manner in the drive train of a motor vehicle.

The Slave Cylinder 1 is realized in this embodiment as a so-called Concentric Slave Cylinder 1 (CSC/"Concentric Slave Cylinder"). The slave cylinder 1 thus overall is realized in the form of a ring extending around the central longitudinal axis 7. The housing 2 of the slave cylinder 1, which is formed in an annular manner in this way, accommodates a piston 4 in the form of an annular piston in a displaceable manner. The piston 4 has a seal 5 (sealing ring; here a lip seal ring) which, together with the housing 2 (annularly), delimits the pressure chamber 3. The radially inner side of the seal 5 bears tightly against the (radially) inner wall 8 of the housing 2. Radially to the outside, the seal 5 bears against a (radially) outer wall 9, which is arranged radially outside the inner wall 8. The piston 4 is coupled in a non-displaceable manner to an axially outer actuating bearing 10 (engagement bearing or release bearing as an alternative) of the housing 2, which actuating bearing is realized here in the form of an angular contact ball bearing. In this embodiment, the piston 4 is coupled immovably to the outer ring 11 of the actuating bearing 10. Furthermore, an inner ring 12 of the actuating bearing 10, which is arranged radially inside the outer ring 11, is coupled to the element for actuating the clutch.

As can be seen from the overview of fig. 1 and 2, the piston 4 is accommodated displaceably in the housing 2 on the path of movement which is achieved in normal clutch operation, i.e. between an extended position, which preferably corresponds to the engaged position of the clutch (disengaged position as an alternative), and a retracted position, which preferably corresponds to the disengaged position of the clutch (engaged position as an alternative). In the usual travel path, the seal 5 bears circumferentially around the housing 2, so that the pressure chamber 3 is sealed off from the surroundings of the housing 2. In the venting position, which is viewed along the longitudinal axis 7 and follows the usual path of travel, i.e. in the venting region (further path of travel) the seal 5 interacts in a targeted manner with the venting recess 6. For this purpose, the venting recess 6 is designed such that the seal 5 is lifted off the outer wall 9 when the piston 4 is moved into the venting region and opens the pressure chamber 3 in a targeted manner to the surroundings of the housing 2. As a result, the pressure chamber 3 is vented in a targeted manner, as indicated by the arrow 13, according to fig. 2.

The shaping of the housing 2 and the venting recess 6 can also be seen more clearly in connection with fig. 3 to 5. In this embodiment, the housing 2 is manufactured entirely from a plastic material. The ventilation recess 6 is preferably formed in prototype technology, for example directly by means of the remaining structure of the housing 2 in the casting process of the housing 2. However, according to other embodiments, the venting recess 6 (as a groove) is also introduced into the housing 2 in a cut-away manner, and is then referred to as a venting groove. The ventilation recess 6 extends with its longitudinal extension along/parallel to the longitudinal axis 7. The venting recess 6 has a specific length such that the sealing element 5 can be vented within the venting area.

According to fig. 4, the venting recess 6 also has a defined width 15 (extension in the circumferential direction) and, in conjunction with fig. 5, a defined depth 16 (radial extension). By means of this geometry, the cross section of the ventilation recess 6 can be individually adapted to the respective region of use. The venting recess 6 is arranged at the highest point of the housing 2, i.e. at the highest point of the pressure chamber 3, radially inside the outer wall 9, with respect to the installed position and acting gravitational field. As is also more clearly shown in fig. 4 and 5, the ventilation recess 6 is integrated in a (radial) thickening 14 of the housing 2, which thickening 14 projects radially inward from a generally circular extension of the housing 2 along an imaginary circular line about the longitudinal axis 7.

The slave cylinder 1 is in this embodiment made entirely of plastic. The piston 4 and the seal 5 are therefore also each made of plastic, in addition to the housing 2.

With reference to fig. 6 and 7, a second exemplary embodiment of a slave cylinder 1 according to the invention is shown, the principle configuration of which and the function of which corresponds to the first exemplary embodiment. For the sake of brevity, only the main differences from the first embodiment are described in the following.

In fig. 6, the housing 2 is no longer made of a plastic material but of metal, here a modified metal sheet (steel or aluminum sheet). The attachment of the venting recess 6 to the outer wall 9 is thus preferably realized via a cold press molding technique pressed in, i.e. embossed profile. As can be seen in fig. 7, the venting recess 6 is formed as an embossing recess radially inside the outer wall 9. The seal 5 is now realized in two parts; i.e. with a first sub-seal on the outer wall 9 and a second sub-seal on the inner wall 8.

In other words, according to the invention, an additional step (thickened portion 14) is partially embedded on the circumference for the venting groove 6 on the pressure chamber 3. There, the seal 5 is then turned over to the side and allows air to escape if necessary. At the same time, a small diameter in the engaged state is ensured, since there is a maximum operating pressure.

The required geometry is depicted in fig. 1 to 5 for a solid plastic CSC 1. In fig. 2, it can be seen that the outer sealing lip extends beyond the vent groove 6 in the lower position. The outer sealing lip is turned over to the side and allows air to escape. The position of the vent slot 6 in the housing 2 can be seen in fig. 3. The ventilation channel is always located at the highest point in the structural space. By means of said geometry, a defined width 15 and depth 16 can be set. The cross section of the ventilation channel 6 can thus be designed according to the pump volume and the dynamic pressure built up. This can be seen in fig. 4 and 5.

For CSC1 with aluminum or cylinder plate pots 2, the recesses 6 can be embossed by means of a stamp. Thus, geometries with undercuts may be achieved. The required geometry is shown in figures 6 and 7.

List of reference numerals:

1. slave cylinder

2. Shell body

3. Pressure chamber

4. Piston

5. Sealing element

6. Ventilation recess

7. Longitudinal axis

8. Inner wall

9. Outer wall

10. Operating bearing

11. Outer ring

12. Inner ring

13. Arrow head

14. Thickened part

15. Width of

16. Depth of field

Claims

1. A hydraulic slave cylinder (1) for a clutch operating device of a motor vehicle, having a housing (2) and a piston (4) which is accommodated displaceably in the housing (2) and which, together with the housing (2), delimits a pressure chamber (3), wherein the piston (4) has a seal (5) which abuts against the housing (2) within the path of displacement of the piston (4) in order to seal the pressure chamber (3) against the environment of the housing (2), characterized in that,

the seal (5) is located on a venting recess (6) of the housing (2) in at least one venting position of the piston (4) adjacent to the displacement path, so that the pressure chamber (3) is open to the surroundings.

2. The slave cylinder (1) according to claim 1, characterized in that the venting recess (6) is arranged at the highest point of the pressure chamber (3) with respect to the acting gravitational field.

3. The slave cylinder (1) according to claim 1, characterized in that the venting recess (6) has a longitudinal extension in the direction of movement of the piston (4) and is realized with a defined width (15) and depth (16).

4. The slave cylinder (1) according to claim 1, characterized in that the venting recess (6) is realized in a radial thickening (14) of the housing (2).

5. The slave cylinder (1) according to any one of claims 1 to 4, characterised in that the housing (2) consists of plastic.

6. The slave cylinder (1) according to claim 5, characterized in that the venting recess (6) is constructed in a prototype technology.

7. The slave cylinder (1) according to any one of claims 1 to 4, characterized in that the housing (2) consists of metal.

8. The slave cylinder (1) according to claim 7, characterized in that the venting recess (6) is made in a stamping technique.

9. A clutch operating device for a drive train of a motor vehicle, having a slave cylinder (1) according to one of claims 1 to 8 and a master cylinder which is hydraulically or couplable to the slave cylinder (1).

10. A clutch system for a motor vehicle drive train having a clutch and a clutch operating device according to claim 9 operatively connected to the clutch.