DE102008063601A1 - Switching device of a gearbox - Google Patents

Abstract

The invention relates to a switching device (1, 50) with at least one rail (2), with a switching element (3) and with a drive unit (5), wherein the switching element (3) is mounted longitudinally displaceable on the rail (2) Drive unit (5) by means of the pressure medium longitudinally driven and the switching element (3) by means of the drive unit (5) can be driven in two opposite longitudinal directions.

Description

Field of the invention

switching device at least with a rail, with a switching element and with a Drive unit, wherein the switching element by means of a guide is mounted longitudinally displaceable on the rail, the drive unit longitudinally drivable by means of the pressure medium and the switching element by means of the drive unit in two opposite longitudinal directions is drivable.

Background of the invention

The Switching device is assisted by means of auxiliary power or operated by foreign power operated gearboxes, in which the shift forks, shift fingers or similar actuators partially supporting the transmission of switching movements or in full by pressure medium on the shift rail along is moved.

Such a switching device is in EP0150583A1 shown, with a synchronizer clutch of a transmission is switched. For this purpose, the Schaltvor device is provided with a switching element in the form of a shift fork. The shift fork is mounted longitudinally movably mounted on a shift rail, which will be called "rail" in the following. The actuated by the pressure medium drive is formed in this case by a drive piston called drive unit. The drive unit is composed of a drive cylinder and its storage on the rail, a partition wall, a return device and share a pressure oil supply. The drive cylinder engages around the rail and is arranged on this longitudinally displaceable.

Of the Drive cylinder is a hollow body, the inside two pressure chambers having. The two pressure chambers are separated by the partition wall separated. The partition is fixed on the rail. The two pressure chambers are the longitudinal channels of the Pressure oil supply, which transversely into the respective pressure chamber open, acted upon with pressure medium.

The Shift fork is attached to the drive cylinder and over this supported transversely to the longitudinal direction and longitudinally movable stored.

Of the Seat of the drive cylinder on the rail is due to functional and manufacturing reasons backlash. The drive cylinder is under the influence of Forces, with which the shift fork against acting on the shift fork Forces on the drive cylinder is supported, tilt. By tilting the pressure chamber is against the surrounding construction or highly loaded in the reverse direction sealing gasket. The seal assembly is correspondingly expensive.

The Bearing points where the drive cylinder is on the rail supported by the attacking on the switching element Forces heavily loaded. The drive cylinder tilts in the depository opposite the rail. longitudinal movements the tilted drive cylinder lead to premature Wear in the guides.

One Another problem is that the pressure chambers in the absence the supply of hydraulic pressure means run empty and themselves fill with air. This leads to commissioning and delayed upon activation of the switching device with pressure means Reactions, as these are only vented.

When Hydraulic pressure means is often used in such switching devices the gearbox used. Transmission oil is usually through Whirling in vehicle operation enriched with air. Otherwise non-compressible fluid could be due to mixing become partially compressible with air and when using pressure-tight pressure chambers to delayed reactions during Switching lead.

Summary of the invention

The The object of the invention is therefore to provide a switching device, with the aforementioned disadvantages are avoided.

These Task is by a switching device according to the subject of the Claim 1 solved.

The Switching device according to the invention is characterized by at least a means of pressure longitudinally (axially) driven drive unit formed, which are mounted separately to the switching element on the rail is. With the drive unit, the switching element is at least longitudinal slidably drivable on the rail.

The Drive unit is at least a drive cylinder and piston elements educated.

Under Drive cylinder is in the context of the invention, a hydraulic component in which pressure can be built up, that in essentially cylindrically shaped, inside but also from the cylindrical Form may have different cross-sections. Outside is the drive cylinder designed arbitrarily and can both from the cylindrical as well as deviating from a symmetrical shape be.

The Drive unit has two longitudinally in opposite directions pointing and longitudinally displaceable on the rail piston elements on. Of the piston elements each defines a pressure chamber for the Pressure medium in the drive cylinder in another longitudinal direction as the other one. The drive cylinder is separate and independent from the guide across the piston elements transversely (radially) stored on the rail. The piston elements are longitudinally movable stored on the rail. The drive cylinder sits on the piston elements and surrounds it with its inner surface. As part of Relative movements arising from games and elastic deflections between the drive cylinder and switching element are thus wanted and possible.

following listed embodiments of the invention are provided.

The The switching device according to the invention has at least a switching element. The switching element is by means of a to Drive unit separate guide longitudinally displaceable mounted on a rail and is for example a shift fork, but can also be a shift finger or a lever or mechanism be to transfer switching movements.

The Switching element sits longitudinally movable on a circumscribed by the term "rail" Rod, shaft, bolt, shift rail or other longitudinal conceivable guide element, on which a switching element is longitudinally movable can be.

The Switching element has, for example, a linear guide and Preferably, a linear bearing, with which the switching element against transverse to the longitudinal direction directed forces on the Rail supported and longitudinally movable on the rail is stored. The switching element is preferably with two linear guides guided, which are spaced apart longitudinally. The linear bearing can be a rolling bearing with rolling elements or a plain bearing. The plain bearing is for example by a sliding bush formed or made of the material of the support or from the switching element.

lever are either air or preferably hydraulic fluids, in particular gear oils.

Of the Drive cylinder takes according to the invention at least two longitudinally pointing and acting in opposite directions and on the rail longitudinally displaceable piston elements on. The piston elements are, for example, annular formed and have on their inner circumference in each case a seat or a storage facility for longitudinally movable storage of the drive cylinder.

The Drive unit is characterized by at least one drive cylinder, the optionally end by cover or seals and preferably is sealed by the piston elements, and by an oil supply educated. Drive unit therefore consists at least of the drive cylinder and optionally from the lid and from the piston elements. oil is preferably over by the oil supply at least one initially in the longitudinal direction in the rail and then transverse channel in the pressure chamber or into and out of the pressure chambers. alternative can connections for the oil supply also on the drive cylinder, on the piston elements or on the Be lids.

Of the Drive cylinder is an at least inside cylindrical part, the Preferably, a cylindrical sleeve made of sheet metal, the but alternatively cast, for example using Light metal alloys can be designed.

Drive cylinder and piston elements are fixed according to one embodiment of the invention and preferably connected to each other pressure-tight. In this case, drive cylinder and piston elements also be integrally formed with each other. However, the drive cylinder is preferably a single part, which is slidably mounted on the piston elements.

The Piston elements are made of plastic, alternatively of light metal alloys made or preferably sheet metal parts. The piston elements are seal carriers. At least one seal sits in the piston member and seals against a sealing surface from the rail. As the drive cylinder with the piston elements moved against the rail, this seal is dynamic designed for longitudinal movements. The respective piston element Optionally takes on a seal on the outside, against seals the drive cylinder. Since piston elements and drive cylinder in the switching device longitudinally relative to each other immovable are arranged, this seal acts static.

The Sealing surface on the rail is either the surface the rail itself or a sleeve or the like, that in order to improved sealing surface on the rail put on or pressed or otherwise attached to the rail is. The sealing surface on the drive cylinder is preferably the smooth inner surface of the drive cylinder itself.

Of the Drive cylinder is formed separately from the guide and is longitudinally between the linear guides of Support arranged. According to one embodiment of the invention is the drive cylinder form-fitting with the support so movably coupled or in both longitudinal directions the guide struck that relative movements of the drive cylinder towards the leadership are possible, the Drive cylinder but at least when driving against the leadership can strike. For this purpose, the drive cylinder is longitudinal, for example arranged almost free of play between two linear guides. Alternatively, the drive cylinder is in both longitudinal directions Movable and tackable away from the lead. Important is that the drive cylinder opposite the guide so relatively mobile is that no reactions of movements, forces and moments acting on the switching element, transferable to the drive cylinder are.

All over the switching element introduced into the prop static and dynamic factors are in the inventive Device of the linear guides of the support added. Such an arrangement has the advantage that the by longitudinal movement dynamically loaded seals in the Drive cylinder of lateral forces are free, since this in the Unlike the prior art switching devices none Reactions from the factors influencing the switching element must record. Tilting in the seal seat is therefore not possible.

A Further embodiment of the invention provides that the drive cylinder having two pressure chambers separated by a partition are separated. The partition is attached to the rail. The partition is made of plastic, light metal or preferably one or more parts formed from sheet metal. The two pressure chambers are sealed from each other. For this purpose, at least one seal is attached to the partition, the seals against the drive cylinder.

A Another embodiment of the invention provides at least one self-closing valve preferably for venting the pressure chamber or the pressure chambers in front. About the valve may possibly pressure in the pressure chamber Air in the chamber escape from the drive cylinder. The valve is, for example, through a diaphragm that works on pressure differences reacted, formed. The diaphragm lifts off a valve seat when higher pressure prevails in the pressure chamber than in the pressure chamber Surroundings. If a small pressure difference between inside and outside prevails or if same pressures (for example, in atmospheric pressure) in the pressure chamber and the environment prevail, the membrane closes the valve seat.

• – Dichten – Erhalten des Öldrucks in der druckbeaufschlagten Druckkammer. Das Ventil ist so ausgelegt, dass der durch Öffnen des Ventils entstehende Leckölverlust so gering ist, dass die Funktion des Antriebszylinders nicht beeinträchtigt ist.
• – Entlüften – Wenn in der Druckkammer Überdruck gegenüber der Umgebung der Schaltvorrichtung vorherrscht, hebt öffnet das Ventil und entlüftet den Druckraum. Geringe Leckölmengen während des Betriebs werden in Kauf genommen und sind nicht schädlich.
• – Auslaufen verhindern – Wenn die Druckdifferenz beispielsweise bei Stillstand des Fahrzeugs nachlässt oder Null ist, schließt das Ventil wieder. Das in der Druckkammer befindliche Öl kann dadurch bei Stillstand des Fahrzeugs in Abhängigkeit von Ausführung und Verlauf der Ölversorgung zumindest teilweise in der Druckkammer gehalten werden. In einer Antriebseinheit mit zwei Druckkammern sind die beiden Druckkammern im Schaltbetrieb wechselseitig mit Druckmittel beaufschlagt. Das Selbstschlussventil der druckbelasteten Kammer ist geöffnet. Das Selbstschlussventil der in dem Moment unbelasteten Druckkammer ist geschlossen. Für wechselseitige ständige Entlüftung während des Schaltbetriebs ist gesorgt.
• – Beschleunigung der Entleerung – In einem Antriebszylinder mit zwei Kammern, wird sich bei Längsverschiebung des Schaltelements das Volumen der mit Druck beaufschlagten Kammer vergrößern und das Volumen der unbelasteten Kammer verkleinern. Beim Erreichen einer Endstellung wird das Volumen der bisher unbelasteten Druckkammer klein sein. Im Extremfall ist dieses nahezu Null. Das Volumen der bisher druckbelasteten Druckkammer hat sich um den Betrag vergrößert, um den sich das Volumen in der anderen Kammer verringert hat und kann somit im Extremfall dem Doppelten seiner Ausgangsgröße entsprechen. Die Druckkammer mit großem Volumen ist mit Öl gefüllt. Beim Wechsel der Schaltrichtung wird sich das Volumen der großen Kammer verringern und das darin befindliche Öl muss möglichst schnell aus dieser verdrängt werden. Ansonsten ist mit unnötigen Druckaufbau in der nicht beaufschlagten und sich verkleinernden Kammer und somit mit unerwünschten Widerstand zu rechnen. Ein Ventil könnte so ausgelegt sein, zum Beispiel eine Dichtlippe könnte so ausgerichtet sein, dass dieses aufgrund der mit der Verdrängung des Öls entstehenden Druckdifferenz öffnet und das Öl schnell aus der Kammer verdrängt werden kann.

Accordingly, the term self-closing valve hides a device which opens and closes the pressure chamber with respect to the surrounding construction and which responds to pressure differences between the surrounding structure and the pressure chamber. At overpressure in the pressure chamber opens this valve. At low pressure differences, the valve automatically returns, for example, by spring force or elastic self-biasing in its closing starting position. The self-closing valve can fulfill four functions:

• - Density - Preservation of the oil pressure in the pressurized pressure chamber. The valve is designed so that the leakage oil loss caused by opening the valve is so small that the function of the drive cylinder is not impaired.
• - Bleeding - When the pressure in the pressure chamber is overpressured relative to the environment of the switching device, it raises the valve and vents the pressure chamber. Small amounts of oil leakage during operation are accepted and are not harmful.
• - Prevent leakage - If the pressure difference decreases, for example when the vehicle is at a standstill or zero, close the valve again. The oil in the pressure chamber can be held at least partially in the pressure chamber at standstill of the vehicle depending on the design and course of the oil supply. In a drive unit with two pressure chambers, the two pressure chambers are alternately pressurized in switching operation with pressure medium. The self-closing valve of the pressure-loaded chamber is open. The self-closing valve of the momentarily unloaded pressure chamber is closed. For mutual constant ventilation during switching operation is taken care of.
• - Acceleration of emptying - In a drive cylinder with two chambers, the longitudinal displacement of the switching element, the volume of the pressurized chamber will increase and reduce the volume of the unloaded chamber. When reaching an end position, the volume of the previously unloaded pressure chamber will be small. In extreme cases, this is almost zero. The volume of the previously pressure-loaded pressure chamber has increased by the amount by which the volume in the other chamber has decreased and thus can in extreme cases correspond to twice its initial size. The large-volume pressure chamber is filled with oil. When changing the switching direction, the volume of the large chamber will decrease and the oil contained therein must be displaced as quickly as possible from this. Otherwise is to be expected with unnecessary pressure build-up in the uninvited and decreasing chamber and thus with unwanted resistance. A valve could be so designed, for example, a sealing lip could be oriented to open due to the pressure difference created with the displacement of the oil, and the oil can be quickly displaced from the chamber.

The Self-closing valve is preferably a seal with which the Pressure chamber opposite the surrounding construction or opposite the pressure chamber is sealed. It is conceivable two of these valves insert, one of which in the one longitudinal direction and the other seals in the other longitudinal direction. The Seal seals the pressure chamber preferably between the piston element and the drive cylinder from, but can alternatively also between Seal the piston element and the shift rail. It sits the Seal preferably on the piston element.

The Seal has at least one sealing lip on the pressure differences responding. When in the pressure chamber over pressure prevails the environment of the switching device, lifts the sealing lip of Sealing seat and vented the pressure chamber if necessary. If the pressure difference, for example, at standstill of the vehicle decreases or becomes zero, the sealing lip sets again elastically biased to the sealing surface.

Description of the drawings

The Invention will become apparent from the following drawings described. Show it.

1 an overall view of an embodiment of a switching device according to the invention,

2 a longitudinal section through the switching device after 1 in a vertical plane E,

3 a further embodiment of a switching device according to the invention in a longitudinal section and

the 4 and 5 the detail Z from the 2 and 3 in an enlarged and not to scale, wherein a formed by a lip seal self-closing valve in 4 closed and in 5 is shown open.

1 and 2 - The 1 and 2 show a switching device 1 for an unillustrated gear change transmission. The switching device 1 has a rail 2 , a switching element 3 in the form of a shift fork 4 and a drive unit 5 on. The shift fork 4 is by means of a guide 6 longitudinally displaceable on the rail 6 stored. The leadership 6 is through a base plate 7 ( 2 ), through two front panels 8th and 9 and two linear guides 15 educated. The base plate 7 is in each case by means of a plug connection 10 on the front panels 8th and 9 recorded and secured for example by form or material connection to this.

The switching device 1 also has side plates 11 and 12 on which stabilize and on which other functional elements such as transmission elements for switching movements or encoder 13 a Wegmesssensorik or can be attached.

The front panels each have a collar 14 on, the part of the relevant linear guide 15 is. With the linear guide 15 are the one above the base plate 7 and side plate 12 connected front panels 8th and 9 on the rails 2 mounted longitudinally displaceable and supported transversely. The linear guide 15 has in this case as a linear bearing a sliding bushing 16 on, which can alternatively be a rolling bearing. Between the front panels 8th and 9 or the linear guides 15 the leadership 6 is the drive unit 5 arranged.

3 - The switching device 50 to 3 has substantially the same structure as the switching device 1 and differs only in the structure of leadership 51 and the switching element 3 of this. The leadership 51 is a peripheral closed component, such as light metal, and is on one side by a bottom 52 and on the other side by a lid 53 locked. The lid 53 sits in the component. The linear guides 15 are at the bottom 52 and in the lid 53 educated. With the linear guide 15 is the lead 51 on the rails 2 mounted longitudinally displaceable and supported transversely. The linear guide 15 also has a sliding bush as a linear bearing in this case 16 on, which can alternatively be a rolling bearing. The switching element 3 is integral with the leadership 51 and as a shift fork 54 cupped.

2 and 3 - The drive unit 5 both switching devices 1 and 50 is from a drive cylinder 17 and two piston elements 18 and 19 educated. The drive cylinder 17 is through a thin-walled hollow cylindrical metal sleeve 20 formed on the piston elements 18 and 19 is deferred, and limits two pressure chambers 21 and 22 , The pressure chambers 21 and 22 are through a partition 23 separated from each other.

The partition 23 is double-walled from two sheet metal parts 24 educated. The sheet metal parts 24 are sleeve-like with edge 25 as well as a bunch 26 trained and each have a crank 27 on. The sheet metal section from which the bend 27 Shaped is running from the edge 25 from first in the longitudinal direction and then in an annular disc section 28 transverse to the central axis 29 the rail 2 , The sheet metal parts 24 each sit with the waistband 26 on the rails. Here are the edges 25 so to each other, that by the longitudinally opposite disc sections 28 a radially (transversely) outwardly open annular groove 31 is limited longitudinally.

In the ring groove 31 sits a sealing ring 30 For example, an O-ring or other shape profile with which the pressure chambers 21 and 22 sealed against each other. This is the sealing ring 30 outwardly directed to the sheet metal sleeve 20 sealingly. The sealing ring 30 is dynamically loaded, since in switching operation of the switching device 1 the drive cylinder 17 relative to the partition 23 emotional.

The piston elements 18 and 19 are each with a seal 32 and a seal 33 Mistake. The seals 32 seal radially inward on the rail 2 from and have at least one sealing edge 58 on. Since the piston elements 18 and 19 in switching operation of the switching device along the rail 2 move, are the seals 32 loaded dynamically. The seals 33 are directed radially outward and are biased to the drive cylinder 17 at. The seals 33 are statically loaded, as these are in the switching operation of the switching device 1 with the drive cylinder 17 along the same direction.

The drive piston 12 is about the piston elements 18 and 19 on the rails 2 stored. The drive cylinder 17 is with at least as much axial play "A" between the front panels 8th and 9 the leadership 6 or the ground 52 and lid 53 the leadership 50 guided, without being clamped by this longitudinally. The drive cylinder 17 the switching device 50 is also transverse to the radial play "S" to the leadership 51 spaced as the drive cylinder 17 on the piston elements 18 and 19 this is "floating" on the seals 32 and 33 supported.

The switching device 1 respectively. 50 is supplied with hydraulic fluid by a pressurized oil supply. The in the switching device 1 respectively. 50 integrated components of the pressure oil supply are a feed pipe 34 with pressure seals 35 , Cross channels 36 . 37 and 45 as well as longitudinal channels 39 and 40 , The feeding pipe 34 sits in the inside hollow rail 2 and is in this by means of three sealing seats 38 . 43 and 44 pressure-tight radial (transverse) in the rail 2 supported. The sealing seats 38 have side walls 41 on, which has a circumferential groove 42 limit. In the circumferential groove 42 sits the pressure seal 35 in the form of an O-ring.

The supply and discharge of the pressure medium to the pressure chamber 21 takes place via the trained as an annular channel longitudinal channel 39 and over the cross channels 36 and 37 , The ring channel is inside through the surface 46 of the feeding pipe 34 and outside through the inner surface 47 the rail 2 limited and in axial directions through the sealing seats 38 and 43 with the pressure seals 35 sealed.

The supply and discharge of the pressure medium to the pressure chamber 22 takes place via the longitudinal channel 40 inside the feeding tube 34 , at least one circumference in the feed tube 34 introduced transverse opening 48 , a ring channel 49 and over the cross channel 45 , The longitudinal channel 40 is closed at one end. The ring channel 49 is in axial directions through the sealing seats 43 and 44 with the pressure seals 35 sealed.

The switching element 3 gets in through the directional arrow 55 marked longitudinal direction are moved by the pressure chamber 21 would be acted upon with pressure medium. The piston element 18 would be applied and longitudinally against the front panel 9 or firmly in the leadership 51 sitting lid 53 struck that the leadership 6 respectively. 50 moved longitudinally. This increases the volume of the pressure chamber 21 by the amount at the same time the volume of the pressure chamber 22 reduced. Eventual in the pressure chamber 22 located oil would be displaced from this. Any air in the pressure chamber would be squeezed out of this.

4 - 4 shows the detail Z from the 2 and 3 , The seal 33 is as a self-closing valve 56 designed. The sealing lip 55 the seal 32 is self-closing by its own bias radially to the drive cylinder 17 when the pressure chamber 21 not pressurized. The sealing lip closes 55 the pressure chamber 21 and seals them against the environment.

5 - 5 shows the detail Z from the 2 and 3 when the pressure chamber 21 is pressurized. The as a self-closing valve 56 designed sealing lip 55 due to the pressure difference between the pressures in the pressure chamber 21 and the environment of the power cylinder 17 lifted and gives an annular gap 57 free, through which air or leaked oil can escape into the environment. The environment is the interior of the housing of the transmission, not shown. reference numeral 1 switching device 31 ring groove 2 rail 32 poetry 3 switching element 33 poetry 4 shift fork 34 feed pipe 5 drive unit 35 pressure seal 6 guide 36 Querkanal 7 baseplate 37 Querkanal 8th front panel 38 sealing seats 9 front panel 39 longitudinal channel 10 connector 40 longitudinal channel 11 side plate 41 Side wall 12 side plate 42 Side wall 13 Transmission element or encoder 43 sealing seat 14 Federation 44 sealing seat 15 linear guide 45 Querkanal 16 bush 46 surface 17 drive cylinder 47 Inner surface area 18 piston element 48 transverse opening 19 piston element 49 annular channel 20 sheet metal sleeve 50 switching device 21 pressure chamber 51 guide 22 pressure chamber 52 ground 23 partition wall 53 cover 24 Sheet metal part 54 shift fork 25 edge 55 sealing lip 26 Federation 56 Self-closing valve 27 cranking 57 annular gap 28 disk portion 58 sealing edge 29 central axis 30 seal

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• EP 0150583 A1 [0003]

Claims (14)

Switching device ( 1 . 50 ) at least with a rail ( 2 ), with a switching element ( 3 ) and with a drive unit ( 5 ), wherein the switching element ( 3 ) longitudinally displaceable on the rail ( 2 ), the drive unit ( 5 ) driven longitudinally by means of the pressure medium and the switching element ( 3 ) by means of the drive unit ( 5 ) is drivable in two opposite longitudinal directions, characterized in that the switching element ( 3 ) separately from the drive unit ( 5 ) on the rails ( 2 ) is mounted transversely and longitudinally displaceable and that the drive unit ( 5 ) at least one drive cylinder ( 17 ) and two longitudinally pointing in the opposite direction and on the rail ( 2 ) longitudinally displaceable piston elements ( 18 . 19 ), each of which has a pressure chamber ( 21 . 22 ) is limited in another longitudinal direction, wherein the drive cylinder ( 17 ) via the piston elements ( 18 . 19 ) separately and independently of the switching element ( 3 ) on the rails ( 2 ) is mounted transversely and longitudinally displaceable. Switching device according to claim 1, characterized in that the drive cylinder ( 17 ) a sheet metal sleeve ( 20 ) is formed, in which the pressure chambers ( 21 . 22 ) are formed and in which the piston elements ( 18 . 19 ) are at least partially arranged. Switching device according to claim 2, characterized in that the piston elements ( 18 . 19 ) the rail ( 2 ) embrace. Switching device according to claim 2, characterized in that at least one of the piston elements ( 18 . 19 ) with at least one rail ( 2 ) and at least temporarily on the railways ( 2 ) sealing gasket ( 32 ) is provided. Switching device according to claim 2, characterized in that at least one of the piston elements ( 18 . 19 ) each with at least one rail ( 2 ) encompassing and at least temporarily on the drive cylinder ( 17 ) sealing gasket ( 33 ) is provided. Switching device according to claim 1, characterized in that each of the piston elements ( 18 . 19 ) a separate pressure chamber ( 21 . 22 ) assigned. Switching device according to claim 7, characterized in that between the pressure chambers ( 21 . 22 ) at least one partition wall ( 23 ) is trained. Switching device according to claim 7, characterized in that the drive cylinder ( 17 ) at the ends by the piston elements ( 18 . 19 ) is sealed, wherein the piston elements ( 18 . 19 ) from the rail ( 2 ) and that the rail ( 2 ) is provided with at least one pressure medium supply and discharge pressure medium supply. Switching device according to claim 7, characterized in that the partition wall ( 23 ) by two longitudinally adjacent sheet metal parts ( 24 ) is formed, wherein at least one of the sheet metal parts ( 24 ) a longitudinally oriented collar ( 26 ), with which the partition wall ( 23 ) on the rails ( 2 ) is attached. Switching device according to claim 9, characterized in that at least one sheet metal parts ( 24 ) has a seal at the edge, the sealing of the drive cylinder ( 17 ) is present. Switching device according to claim 1, characterized in that the pressure chamber ( 21 . 22 ) at least one at pressures of the pressure medium in the pressure chamber ( 21 . 22 ) and self-acting self-closing valve ( 56 ) having. Switching device according to claim 11, characterized in that each of the piston elements ( 18 . 19 ) at least one seal sealing transversely to the longitudinal direction ( 32 . 33 ), wherein at least one of the seals ( 33 ) the self-closing valve ( 56 ). Switching device according to claim 1, characterized in that the switching element ( 3 ) two longitudinally spaced linear guides ( 15 ), via which the switching element ( 3 ) on the rails ( 2 ) is supported and mounted longitudinally displaceable, wherein the drive piston ( 5 ) longitudinally between the linear guides ( 15 ) is arranged. Switching device according to claim 14, characterized in that the piston elements ( 18 . 19 ) longitudinally against the linear guides ( 15 ) are applicable.