DE102017214547A1 - Pneumatic actuating device for a motor vehicle - Google Patents

Abstract

Pneumatic actuating device (10) for a motor vehicle, comprising a working cylinder (14) and a working piston (12) which together define a pressure chamber (16), wherein at least a part of the working piston (12) spans or engages in cross-section a free space (54) wherein within the free space (54) a valve unit (56) is arranged.
In addition, a further pneumatic actuator (10) is proposed.

Description

The invention relates to a pneumatic actuator for a motor vehicle.

There are pneumatic actuators known which are controlled by valve units. In common drive trains, these valve units are usually arranged on a transmission housing. On this basis, the valve units via hoses or pneumatic channels, which are introduced into the respective housing, connected to the pneumatic actuator. This structure requires a long way between a pressure medium filled pressure chamber of the pneumatic actuator and the valve unit. A pneumatic pressure medium spreads in the room, so that a long way to a correspondingly long duration of operation result. Due to these longer dead times increased control effort is necessary to the pneumatic actuator unit defined and disengaged. In addition, the arrangement of the valve unit on the transmission housing requires space within the drive train.

It is therefore an object to provide a pneumatic actuator, which has low dead times during actuation processes and also saves installation space.

This object is achieved by a pneumatic actuator according to claim 1. The dependent claims represent advantageous embodiments of the pneumatic actuator.

The pneumatic actuator explained in detail below is suitable for a motor vehicle. Conveniently, this is used in a commercial vehicle having a pneumatic system. The pneumatic actuator has a working cylinder and a working piston. The working cylinder and the working piston are axially movable against each other and sealed against each other.

Pressure chamber is defined by the working cylinder and the working piston. With particular advantage, the pressure chamber is defined exclusively by the working cylinder and the working piston and enclosed by this. In an alternative variant, however, at least one further component can also contribute to a closed pressure chamber. By way of example, this further component can be formed by a radially inner guide tube. For this, the working piston can be firmly and airtightly connected to the guide tube, wherein the working cylinder can slide along the guide tube in the axial direction. Accordingly define or enclose the working piston, the working cylinder and the guide tube pressure chamber airtight. Conveniently, a sealing element is arranged between the working cylinder and the other components, ie in particular the guide tube.

In the pneumatic actuator of the working piston is conveniently fixed and the working cylinder designed to be axially movable. The working piston forms a free space. This free space is defined on the working piston via at least one radially extending portion and an axially extending portion which span this space. For example, the working piston may also be substantially U-shaped or C-shaped, wherein the U or C shape spans the free space. In other words, the clearance is located within the U or C shape. In this last case, the clearance would be formed within the U-shaped working piston.

Within the free space is a valve unit, preferably a plurality of valve units arranged. To operate the valve unit, this is connected to the supply and removal of pressure medium with a pneumatic system, for example via hoses or pneumatic channels, which are formed on a housing. The valve unit is also operatively connected to the pressure chamber, so that the pressure chamber can supply pressure medium or dissipate pressure medium through the valve unit. The supply and discharge of pressure medium is used to disengage and engage the pneumatic actuator for actuating a clutch.

Such an arrangement has two advantages. First, the aforementioned dead time is minimized by the proximity of the valve unit to the pressure space of the pneumatic actuator, so that the timing for the pneumatic actuator is short. In addition, the space within the drive train is optimally utilized by arranging the pneumatic actuator within the free space. By exploiting the space for the arrangement of the valve unit or the valve units space is available to gear housing.

With particular advantage, no component is arranged within the pressure chamber. The pressure chamber is enclosed exclusively by working piston, working cylinder and optionally one or more further components, wherein no other components, such as a biasing spring, are arranged within the pressure chamber. In the engaged state of the pneumatic actuator, so when the clutch is closed and there is a torque connection between the engine and transmission, a volume of the pressure chamber is minimal. In a locked state of Friction clutch, the volume of the pressure chamber can be almost zero, in particular, the pressure-chamber side surfaces of the working piston and cylinder substantially abut each other without a gap.

An arrangement of components within the pressure chamber is not excluded. In particular, a biasing spring can be arranged within the pressure chamber.

This arrangement of the valve unit within the free space is particularly possible by the stationary design of the working piston on the pneumatic actuator, wherein the working cylinder is axially movable relative to the working piston and also with respect to the pneumatic actuator.

The pneumatic actuator is fixedly arranged on a transmission housing, directly or indirectly. The fixed arrangement of the pneumatic actuator is therefore the fixed and immovable arrangement relative to the pneumatic actuator and the housing or the fixed and immovable arrangement relative to the transmission housing, for example by indirect or direct screw.

Accordingly, the working piston has no degree of freedom compared to the other stationary components, such as a mounting element, the pneumatic actuator and in particular can not move axially relative to these. With particular advantage, the working piston is arranged axially fixed to other components of the pneumatic actuator. Immediately or indirectly, the working piston is then firmly connected to a transmission housing of a transmission. The working piston is conveniently bolted to a mounting element. The mounting element in turn is firmly connected to a transmission housing.

In addition, advantageous embodiments of the invention are described.

The pneumatic actuating device expediently has a mounting element for fastening to a drive train, in particular to a transmission housing of the drive train.

The mounting element is conveniently designed as a mounting plate and connected with advantage fixed to the working piston. This connection can be done for example by a screw. The mounting element is favorably disc-shaped. With particular advantage, the guide tube is arranged radially inward on the mounting element and firmly connected thereto, for example by pressing or welding.

With particular advantage, only the working cylinder and the working piston define the pressure chamber. Working cylinder and piston are sealed against each other to provide an airtight pressure chamber. In addition, advantageously no further components are arranged within the pressure chamber. As a result, the dead volume of the pressure chamber can be kept very small. This in turn leads to a rapid response of the pneumatic actuator.

In a preferred embodiment, the working piston is fastened to the mounting element, so that the mounting element at least partially closes off or covers the clearance.

The cheaper way disk-shaped mounting element is used, inter alia, as a cover plate for the free space and for attachment of the working piston. In addition, the mounting element allows the attachment of the pneumatic actuator to another assembly of the drive train, such as the transmission housing. Conveniently, the mounting element covers the working piston, in particular the free space, completely, so that it is protected against ingress of dirt.

Advantageously, at least one opening for the supply and removal of the pressure medium to the valve unit or away from the valve unit is formed on the mounting element. The mounting element may also have a plurality of openings for the supply and removal of pressure medium. Advantageously, the mounting element or the mounting plate is sealed against the working piston. In particular, the mounting plate or the mounting member is sealed at the opening or the openings for the supply and discharge of pressure medium.

The supply and removal of pressure medium to a valve unit can be accomplished for example via a hose, via pneumatic channels in one or more housings, or even a combination thereof.

With particular advantage, the valve unit is operatively connected via a pneumatic channel of the working piston with the pressure chamber.

A pneumatic channel is an opening made in the working piston or a corresponding channel which extends, for example, along or within the working piston. This pneumatic channel can be generated for example by one or more holes. Alternatively, a pneumatic channel can also be introduced by milling into the working piston become. A combination of the mentioned methods and further manufacturing methods is possible.

On the working piston, a pneumatic channel or it may be formed a plurality of pneumatic channels. Conveniently, a plurality of valve units are arranged within the free space on the pneumatic actuator. By way of example, a valve unit for filling the pressure space and a valve unit for venting the pressure space can be used.

A common variant is the use of four valve units in the form of switching valves, which can open and close respectively. By opening and closing, these switching valves release or close a flow with a defined cross-section. Two of the switching valves are provided for filling and the other two switching valves for venting. One of the switching valves for filling has a large diameter and the other switching valve for filling has a relatively small diameter to this. The switching valves for venting are identical or similar. In order to achieve a fast movement of the working cylinder relative to the working piston, both valves are opened. If a slower movement is needed, for example, to make a fine adjustment of the position of the pneumatic actuator, the large flow switching valve or the small flow switching valve is switched.

Alternatively, a control valve for venting and a control valve for venting are formed, wherein this control valve has an adjustable, ie variable diameter, so that the inflow or outflow of pressure medium can be regulated.

Preferably, two or more valve units are arranged within the free space. Advantageously, within the free space and valve units are formed, the other pneumatic components with compressed air supply and venting. This may for example be a transmission brake, which is arranged within a transmission. For this purpose, additional openings may be formed on the mounting element and optionally additional pneumatic channels on the working piston.

It is further proposed that the valve unit is connected directly to the pneumatic channel of the working piston.

The valve unit is connected directly, ie directly, to the pneumatic channel. There is no further component, such as a pneumatic hose necessary. In this way, the shortest possible way from the valve unit to the pressure chamber can be made possible. As already mentioned, a corresponding dead time for filling or venting the pressure chamber is as small as possible. The valve unit or the valve units are conveniently connected directly to the pneumatic channels, preferably attached to this.

In an advantageous embodiment, the pneumatic channel is formed as an opening passing through the working piston.

Such an opening is also referred to as a passage, wherein this is advantageously introduced through a bore or during the manufacturing process, for example during an injection molding process, in the working piston. This direct passage provides the shortest possible path from valve unit to pressure chamber. Conveniently, a separate passage in the form of an opening through the working piston is formed for each valve unit, which serves to fill or vent the pressure chamber.

In an alternative embodiment variant, the pneumatic actuating device has a plurality of valve units and a plurality of pneumatic channels, wherein the valve units are operatively connected to the pressure chamber via a network of pneumatic channels.

The network of pneumatic channels provides a connection between the pressure-chamber-side connections of the valve units. The network is connected to the pressure chamber via one or more pneumatic channels. Optionally, a separate network of pneumatic channels or a common network of pneumatic channels can be designed for the valve unit (s) for aerating and venting the pressure chamber. The pneumatic channels of the network are favorably formed on or within the working piston, so that no additional components for the connection between the valve unit and the pressure chamber, such as pneumatic hoses, are needed.

The working piston may have at least one pressure medium supply / discharge channel for supplying and discharging pressure medium from the pneumatic system to the valve unit. This can be exemplified, as the pneumatic channels, incorporated into the working piston, in particular via drilling, milling or even during an injection molding process. Alternatively, a supply / discharge hose can be used, which conveniently reaches through an opening of the mounting element.

With particular advantage is a terminating in the pressure chamber section of a pneumatic channel or a breakthrough nozzle-shaped or conical.

This section ends with advantage directly in the pressure chamber. The section is conveniently formed conically widening to the pressure chamber. A cross-sectional area, particularly a diameter, of this portion becomes monotonously larger toward the pressure space. This nozzle-shaped or conical design of the end portion allows a particularly advantageous inflow and outflow of the pressure medium into or out of the pressure space.

It is further proposed that the working piston is designed in several parts. This multi-part allows a simpler and more accurate production of the working piston.

In a particularly advantageous embodiment variant, the multi-part working piston has a base body, which defines the free space, and a cover body which seals the pneumatic channels of the base body in an airtight manner.

The main body allows the space-saving and close to the pressure chamber arrangement of the valve unit on the pneumatic actuator. On the body pneumatic channels are formed. The pneumatic channels can be introduced, for example by milling in the body. The cover body is firmly connected to the base body and covers the pneumatic channels airtight. Optionally, one or more seals are formed between the base body and the cover body, which seal the pneumatic channels with each other and with respect to the pressure chamber. The cover body advantageously has at least one opening which provides an operative connection between the pneumatic channels of the base body and the pressure chamber. The opening may be formed, for example, by a passage in accordance with the above explanations, and optionally also in the form of a nozzle or conical for a better inflow and outflow of the pressure medium.

It is further proposed that a preload spring is formed radially outside or radially within the pressure chamber. The preload spring serves for preloaded contact of the pneumatic actuation device, in particular a release bearing, on a diaphragm spring of the coupling. The arrangement of the preload spring radially outside or radially within the pressure chamber makes it possible to form the pressure chamber free of other components. This is advantageous because the dead space of the pressure chamber can thereby be kept as small as possible, whereby a quick and comfortable response of the pneumatic actuator is achieved. The preload spring acts between the working cylinder and the working piston, which can be arranged in each case directly or indirectly on the working cylinder and the working piston. By way of example, the preload spring is arranged between a sliding element and the mounting element and is in contact with them, whereby an indirect connection between the working piston and the working cylinder is produced.

It is further proposed that a valve unit arranged within the free space is operatively connected to a further pneumatic construction device, in particular a transmission brake.

The arrangement of the valve unit within the pneumatic actuator is particularly space-saving and allows common supply / discharge channels for the various valve units. The further pneumatic construction device can be, for example, a transmission brake, which can be arranged within a transmission housing. The further construction device is normally not formed on the pneumatic actuator, but on another assembly, such as a transmission. On the pneumatic actuator unit preferably further lines, pneumatic channels or hoses are formed, which provide a connection of the respective valve unit with its other pneumatic units. Optionally, a combination thereof may also be used.

It is further proposed that a holding element is attached to the working cylinder.

The holding element is favorably designed as a holding plate having a disc shape. The holding element is firmly connected to the working cylinder and performs together with this an axial movement relative to the working piston. A component of a sensor unit is advantageously fixedly arranged on the holding element, for example a position transmitter of the sensor unit. The axial movement of the position sensor and the working cylinder is detected by a sensor electronics. Conveniently, a spring element is arranged between the retaining element and the release bearing. This spring element is in particular in abutting contact with a support portion of the holding element, so that the spring element biases the release bearing in the axial direction relative to the pneumatic actuating device, in particular the working cylinder. This allows a captive and self-centering arrangement of the release bearing on the pneumatic actuator.

It is also proposed a pneumatic actuator for a motor vehicle according to claim 10.

The pneumatic actuating device has a working cylinder and a working piston which define a pressure chamber. The pressure chamber is conveniently surrounded exclusively by the working cylinder and the working piston, which seals against each other. In an alternative variant, the pressure chamber is enclosed by the working cylinder, the working piston and at least one further component. The working piston, the working cylinder and the other component are sealed accordingly to provide an airtight pressure chamber. The working cylinder is in this case formed axially movable relative to working piston.

With particular advantage, the working piston is fixedly arranged on the pneumatic actuator, whereas the working cylinder is designed to be axially movable on the pneumatic actuator. Stationary means that the working piston is fixedly arranged on the pneumatic actuating device and is substantially immovable relative to a housing and also to other assemblies of the drive train.

The pneumatic actuating device has a dirt deflector unit, which is fastened directly or indirectly to the working piston and which is in contact with the working cylinder via a stripping element which is fastened to the dirt deflector unit. The working cylinder can move in the axial direction relative to the dirt deflector unit. The dirt deflector unit preferably surrounds the working cylinder and the working piston radially on the outside, so that the pressure chamber is optimally protected against penetrating dirt.

The dirt deflector unit is advantageously sleeve-shaped and has a covering body and a stripping element, which is fastened to the covering body, preferably directly. The cover body advantageously has the aforementioned sleeve shape, so that working cylinder and working piston are enclosed over a large area, and is favorably formed from plastic. The stripping element is advantageously formed from a felt. The stripping element can be arranged, for example, in a circular circumferential groove of the stripping element.

The scraper slides on the cylinder and wipes off dirt particles that have accumulated on the cylinder, so that no dirt can penetrate into a space enclosed by the Schmutzabweisereinheit interior.

The cover body is conveniently indirectly or directly attached to the working piston. This attachment may be formed, for example, by snap hooks, which are exemplary in openings of a mounting member and snap on this.

The stripping element is advantageously arranged on the cover body axially opposite the fastening or corresponding fastening element, such as snap hooks. The stripping element is also advantageously arranged on the axially in the disengagement direction facing end of the cover body. The stripping element is advantageously arranged radially on the inside of the cover body.

In a particular embodiment variant, the dirt deflector unit or the cover body has an axial extension which corresponds approximately to the axial extent of the working cylinder. The covering body is therefore approximately as long in the axial direction as the axial extension of the working cylinder, preferably slightly shorter.

• 1 eine pneumatische Betätigungseinrichtung mit ortsfesten Arbeitskolben im Querschnitt;
• 2 die pneumatische Betätigungseinrichtung aus 1 in einer perspektivischen Frontansicht;
• 3 die pneumatische Betätigungseinrichtung aus 1 in einer perspektivischen Rückansicht;
• 4 eine rückseitige perspektivische Darstellung eines Arbeitskolbens mit mehreren Ventileinheiten;
• 5 eine schematische Darstellung eines mehrteiligen Arbeitskolbens im Querschnitt.

The pneumatic actuator will be explained in detail below by way of example with reference to several figures. Show it:

• 1 a pneumatic actuator with stationary working piston in cross section;
• 2 the pneumatic actuator off 1 in a perspective front view;
• 3 the pneumatic actuator off 1 in a perspective rear view;
• 4 a rear perspective view of a working piston with a plurality of valve units;
• 5 a schematic representation of a multi-part working piston in cross section.

The 1 shows a pneumatic actuator 10 in cross section. The same pneumatic actuator 10 is also in the 2 and 3 shown in perspective. The pneumatic actuator 10 is intended for installation in a motor vehicle, in particular in its drive train.

The pneumatic actuator 10 has a working piston 12 as well as a working cylinder 14 on. The working piston 12 and the working cylinder 14 are axially movable with each other. The working piston 12 and the working cylinder 14 define a pressure chamber 16 and close this pressure chamber 16 with the help of sealing elements 18 airtight.

To actuate a coupling, not shown, the pressure chamber 16 with a pressure medium, in this case a pneumatic medium, especially air, filled. As a result, the working cylinder moves 14 axially opposite the working piston 12 and actuates a diaphragm spring, not shown, via a release bearing 20 ,

The pneumatic actuator 10 has a stationary working piston 12 on. This means that the working piston is fixed to a mounting element 22 is connected and not facing this, which is a kind of housing for the pneumatic actuator 10 represents, can move. The solid connection is by screws 24 provided. The mounting element 22 is as a mounting plate 22 trained and serves among other things the attachment of the pneumatic actuator 10 on further components of the drive train, for example on a transmission housing.

The working cylinder 14 is radially fixed inside with a sliding element 26 connected, for example by pressing and / or welding. The sliding element 26 leads with the working cylinder 14 a common axial movement and slides on a guide tube 28 , The sliding element 26 absorbs forces introduced into the release bearing and introduces them into the guide tube. On the sliding element 26 are a scraping element 30 as well as two slip rings 32 educated.

The guide tube 28 in turn is fixed to the mounting element 22 connected. This is the mounting element 22 at its radially inner periphery to form a mounting portion 22a bent in the axial direction. The attachment section 22a and the guide tube 28 For example, they are pressed together and / or welded together. In particular, the connection between the mounting element and guide tube is formed at least dirt particle density.

The working cylinder 14 , the sliding element 26 , the guide tube 28 as well as the mounting element 22 form a space 34 out. Inside this room 34 is a spring element 36 arranged. The spring element 36 serves as preload spring 36 for the pneumatic actuator 10 ,

The working cylinder 14 and the release bearing 20 be through the spring element 36 axially biased against a diaphragm spring, not shown, of the clutch. The spring element 36 is radially inside the Ausrückarbeitszylinders 14 and thus also radially within the pressure chamber 16 , ie in particular not in the pressure chamber 16 , educated. The dead space in the pressure room 16 is thereby reduced to a minimum, whereby a quick and comfortable disengagement of the pneumatic actuator is achieved. Besides, that's in the room 34 arranged spring element 36 , in particular due to the stripping element 30 , particularly well protected against ingress of dirt.

At the pneumatic actuator 10 is also a holding element 38 educated. The holding element 38 is fixed to the working cylinder 14 connected and performs with this a common axial movement. Here is the holding element 38 disc-shaped, for example, as a sheet metal part, and has substantially a rotationally symmetrical shape.

At its radially inner portion, the holding plate 38 a support section 38a on. At this support section 38a engages a spring element 40 on which an axial preload on the release bearing 20 in the direction of the working cylinder 14 exercises, so the release bearing 20 is arranged captive and self-centering on the pneumatic actuator.

The holding element 38a has at the radially inner end of a deformation, the support of the spring element 40 serves. The spring element 40 is supported in the axial direction on the support portion 38a and causes an axial spring force on the radially outer bearing ring of the release bearing 20 in the direction of the working cylinder 14 , The release bearing can thus move in the radial direction to perform a self-centering, but is still secured captive.

Furthermore, the holding element 38 at its radially outer end a mounting portion 38b on, the attachment of a position sensor 42 a sensor unit 44 serves. The position transmitter 42 performs a joint movement with the working cylinder 14 out, with a sensor electronics 46 the sensor unit 44 the position and movement of the position sensor 42 detected.

The pneumatic actuator 10 also has a dirt deflector unit 48 put on a cover body 50 and a stripping element 52 includes. The cover body 50 is formed of plastic and has a sleeve shape, wherein the cover body 50 substantially radially outward in the axial direction along the working cylinder 14 extends. This shields the cover body 50 the working cylinder 14 and the working piston 12 from penetrating dirt.

The dirt deflector unit 48 is through the cover body 50 who has several snap hooks 50a has, on the mounting element 22 attached. The cover body 50 can be used as an example of other fastening means fixed to the mounting element 22 be connected. The attachment can for example also with respect to the working piston 12 happen. In particular, the dirt deflector unit 48 directly or indirectly fixed to the working piston 12 connected.

The working cylinder 14 moves accordingly in the axial direction relative to the soil deflector unit 48 and its stripping element 52 , which radially outward on the working cylinder 14 comes to the investment contact. This scraping element 52 For example, it is formed of felt and wipes off dirt deposited on itself on the radially outer surface of the working piston 12 located. In particular, the stripping element is circularly encircling in a groove of the cover body 50 arranged, in particular radially inward on the cover body 50 ,

The dirt deflector unit 48 , in particular its covering body 50 extends in the axial direction favorably at least over the axial stroke of the working cylinder 12 , By this arrangement, the dirt deflector unit 48 and the sealing elements 18 a particularly advantageous dirt shield is possible. In particular, incoming debris must travel a very long distance from the stripping element 52 up to the mounting element 22 and then again in the reverse direction to the sealing element 18 cover in order to finally be able to penetrate into the cubic capacity. This structure makes the penetration of dirt into the pressure chamber considerably more difficult and leads to a longer service life.

The dirt deflector unit 48 , in particular the cover body 50 and the stripping element 52 are rotationally symmetrical. In the 2 and 3 you can tell that the snap hook 50a are distributed substantially uniformly on the circumference.

The stationary working piston 12 has a radial section 12a and two axially extending sections 12b and c on. The axial section 12b is radially outside the axial section 12c arranged. A radial section 12a and an axial section 12b or 12c create a free space 54 on, which is described in cross-section through a quadrilateral, in particular a rectangle.

In addition, the free space 54 also by the cross-section C- or U-shaped working piston 12 encompassed. The radial section 12a as well as the axial section 12b and the axial section 12c accordingly encompass the free space 54 , In addition, the free space 54 from the mounting element 22 covered.

The open space 54 is through the sections of the working piston 12 and by the mounting element 22 surround. Within the free space 54 are several valve units 56 are arranged. A perspective view in a rear view of the working piston is in the 4 shown, which also includes the valve units 56 represents. The valve units 56 are arranged in the free space in the circumferential direction adjacent to each other. However, any other possible arrangement is conceivable, for example, a star-shaped or uniformly distributed arrangement.

The arrangement comprises in particular the on the working piston 12 arranged pressure medium inlet and outlet 58 in the form of a channel. The pressure medium flows in and out via the pressure medium 58 and via pneumatic channels 60 the valve units 56 supplied or led away from this. The concrete flow of pressure medium and the execution or interconnection of the individual pneumatic channels 60 with the valve units 56 should not be continued at this point. It should be noted, however, that the pneumatic channels 60 in the working piston 12 are introduced. By way of example, the pneumatic channels 60 be introduced by drilling or milling.

In the embodiment according to 1 points the working piston 12 several pneumatic channels 60 on, with such a pneumatic channel 60 as axially through the working piston 12 is formed through opening. This allows the shortest possible path between the valve unit 56 and the pressure room 16 , so that a direct response and the lowest possible dead time can be achieved. In addition, the arrangement of the valve units 56 within the existing free space 54 Space saved elsewhere on the drive train.

Here is for each valve unit 56 a separate axial through the working piston 12 passing pneumatic channel 60 educated. In another embodiment, which is already explained in the general part of the description, the valve units via a network of pneumatic channels 60 interconnected, so that, for example, only a common breakthrough 66 is sufficient for the pressure chamber. Optionally, the valve units have 56 for filling and the valve units 56 for venting the pressure chamber 16 each with its own network of pneumatic channels 60 on. According to 1 is the pneumatic channel 60 at the same time also a breakthrough 66 ,

The pneumatic channel 60 as well as a possible breakthrough 66 a network of pneumatic channels 60 have a pressure-chamber-side end portion 66a on, which can be either nozzle-shaped widening or conical. The diameter of this end section 66a expands towards the pressure room. As a result, an improved inflow and outflow behavior of the pressure medium is achieved.

In a further variant, which has also already been carried out in the general description part, the working piston 12 be formed in several parts. This is in 5 exemplified. The multipart working piston 12 includes a main body 62 as well as a cover body 64 , The open space 54 gets through the body 62 clamped. Again, the valve units 56 arranged within the free space.

The valve unit is also here with the pneumatic channels 60 connected. The pneumatic channels 60 are in the main body 62 incorporated, which are shown by dashed lines by way of example. The pneumatic channels 60 form one or more networks for the various valve units 56 out.

The cover body 64 is fixed to the main body 62 connected and covers the pneumatic channels 60 from. In particular, the cover body covers 64 the pneumatic channels 60 airtight. This can be achieved for example by means of a seal, which is not shown, or by an appropriate connection method, such as airtight welding of body 62 and cover body 64 , body 62 and cover body 64 For example, they can also be screwed together. Advantageous are the pneumatic channels 60 or the networks of pneumatic channels 60 against each other and against the pressure chamber 16 sealed.

The cover body 64 has a breakthrough 66 , or alternatively a plurality of openings, on which a connection between the pneumatic channels and the pressure chamber 16 provides. The breakthrough 66 may be formed nozzle-shaped or conical according to the preceding embodiments.

LIST OF REFERENCE NUMBERS

10

pneumatic actuator

12

working piston

12a

radial section

12b, c

axial section

14

working cylinder

16

pressure chamber

18

sealing element

20

release bearing

22

mounting element

22a

attachment section

22b

opening

24

screw

26

Slide

28

guide tube

30

stripping element

32

sliding ring

34

room

36

spring element

38

retaining element

38a

support section

38b

attachment section

40

spring element

42

locator

44

sensor unit

46

sensor electronics

48

Schmutzabweisereinheit

50

covering

50a

snap hooks

52

stripping element

54

free space

56

valve unit

58

Pressure medium inlet and outlet

60

pneumatic channel

62

body

64

cover body

66

breakthrough

66a

pressure chamber side end portion

Claims (10)

Pneumatic actuating device (10) for a motor vehicle, comprising a working cylinder (14) and a working piston (12) which together define a pressure space (16), - Wherein at least a portion of the working piston (12) in cross-section spans or embraces a free space (54) - Wherein within the free space (54) a valve unit (56) is arranged. Pneumatic actuating device (10) according to one of the preceding claims, characterized in that the pneumatic actuating device (10) has a mounting element (22) for attachment to a drive train, in particular to a transmission housing. Pneumatic actuating device (10) according to one of the preceding claims, characterized in that the working piston (12) is fastened to the mounting element (22), so that the Mounting element (22) the space (54) at least partially closes / covers. Pneumatic actuating device (10) according to one of the preceding claims, characterized in that the valve unit (56) via a pneumatic channel (60) of the working piston (12) with the pressure chamber (16) is operatively connected. Pneumatic actuating device (10) according to one of the preceding claims, characterized in that the valve unit (56) connects directly to the pneumatic channel (60) of the working piston (12). Pneumatic actuating device (10) according to one of the preceding claims, characterized in that the pneumatic channel (60) is formed as an opening passing through the working piston (12). Pneumatic actuating device (10) according to one of the preceding claims, characterized in that the pneumatic actuating device (10) has a plurality of valve units (56) and a plurality of pneumatic channels (60), wherein the valve units (56) communicate with the valve via a network of pneumatic channels (60) Pressure chamber (16) are operatively connected. Pneumatic actuating device (10) according to one of the preceding claims, characterized in that the working piston (12) is designed in several parts. Pneumatic actuating device (10) according to one of the preceding claims, characterized in that the multipart working piston (12) has a base body (62) which defines the free space (54) and a cover body (64), the pneumatic channels (60) of the base body ( 62) hermetically seals. Pneumatic actuating device (10) for a motor vehicle, comprising a working cylinder (14) and a working piston (12) defining a pressure space (16), - Wherein the working cylinder (14) is formed axially movable relative to the working piston (12), wherein - A dirt deflector unit (48) which is directly or indirectly attached to the working piston (12) and via a stripping element (52) which is fixed to the soil deflector unit (48), with the working cylinder (14) in abutting contact.

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