DE102012220342B4 - Sealing element for pressure fluid actuator - Google Patents

Abstract

Pressure fluid actuation unit (14) for a clutch arrangement, in particular for a dual clutch (12) of a motor vehicle, comprising a cylinder (68) and at least one actuating piston (70, 72) guided in a fluid-tight manner in the cylinder (68), wherein the cylinder (68) engages in its cylinder wall (74) has at least one bore (132) for a pressurized fluid extending from a bore inlet (134) provided in the cylinder face (79) to a bore outlet (135), the bore outlet (135) being adapted for receiving for the actuating piston (70; 72), so that a fluid connection between a pressurized fluid supply unit and the working space (118; 130) can be provided with the bore (132), wherein the bore (132) and a pressurized fluid supply (144) having an offset, characterized in that at the bore inlet (134) at least one sealing element (136) with a a seal inlet (140) and a seal outlet (142), the seal member (136) providing an offset between its seal inlet (140) and seal outlet (142), sealing with its seal outlet (142) the bore inlet (134) contacted and provided with its offset to the seal outlet (142) arranged sealing inlet (140) with respect to the bore (132) in the cylinder wall (74), on the one hand, the sealing inlet (140) in fluid contact with the pressure fluid supply (144) in fluid contact and on the other hand, the seal outlet (142) is sealingly connected to the bore (132).

Description

The present invention relates to a Druckfluidbetätigungseinheit for a clutch assembly according to the preamble of claim 1, and a dual clutch assembly, in particular for a motor vehicle, according to claim 11.

From the prior art, for example the DE 10 2007 049 879 , Druckfluidbetätigungseinheiten, in particular pneumatic actuation units for vehicle clutches, known in which a pressurized fluid in a working space of a displaceably arranged in a cylinder piston is passed. The piston in turn is designed to bring a clutch in frictional engagement or frictional engagement. In order to direct the pressurized fluid or the compressed air to the working space, recesses are provided in the cylinder and on a connecting plate to be fastened to the cylinder, through which the pressurized fluid passes into the working chamber of the piston.

However, a disadvantage of this actuating unit is that the radial minimum distance of the recess is determined by the radial extension of a seal on the cylinder, so that the actuating element can be used only with sufficiently large available space.

In order to use a pressure fluid actuator even in very small installation spaces or for the operation of a double clutch, in which two actuator units must be arranged in a very small space, therefore, in the prior art, for example DE 10 2010 031 664 , has been proposed to provide the cylinder wall with holes which open into the respective working space of the associated piston. However, to facilitate connection to a pressurized fluid supply unit, the bore may not extend axially through the cylinder wall and the cylinder face, but must have a radial offset realized in the prior art through an angled bore.

The radial offset to the outside is necessary to provide sufficient radial space for a connection seal, without narrowing the radially inner space of the cylinder, otherwise the radially inner piston would no longer be mounted in the cylinder.

A disadvantage of this prior art, however, that the angled bore can be achieved only by a bore of the cylinder wall from two sides, which on the one hand increases the assembly effort and on the other to produce the risk of waste, if the holes do not merge into each other exactly.

Furthermore, the shows DE 10 2009 030 976 A1 a double clutch with an actuator. The dual clutch can perform a tumbling motion during operation. Here, a tube is arranged between two fluid channels, which fluid-tightly connects the two fluid channels and allows a Taumelausgleich.

Object of the present invention is therefore to provide a Druckfluidbetätigungseinheit, which has the lowest possible production costs.

This object is achieved by a pressure fluid actuation unit according to claim 1, as well as a double clutch with such a pressure fluid actuation unit according to claim 11.

The invention is based on the idea of providing a sealing element for a pressure fluid actuation unit having a seal inlet and a seal outlet, wherein the seal inlet has a preferably radial offset relative to the seal outlet. In other words, an offset of the seal inlet with respect to the seal outlet is provided in a lateral plane extending transversely to a pressure fluid flow direction or transversely to a pressure fluid supply.

According to a further aspect of the present invention, the sealing element according to the invention is used on a pressure fluid actuation unit, wherein the pressure fluid actuation unit according to the invention has a cylinder and at least one actuation piston guided in a fluid-tight manner in the cylinder. The cylinder has, as known from the prior art, in its cylinder wall at least one bore for a pressurized fluid, which extends from a provided in the cylinder end bore input to a bore outlet. The bore outlet opens into a designed for receiving a pressurized fluid working space of the actuating piston, so that the bore makes a fluid connection between a pressurized fluid supply unit and the working space. The invention is based on the idea, instead of the known from the prior art obliquely arranged to be formed from two sides hole to drill through the bore axially, but at the hole inlet to provide the sealing element according to the invention with its Dichtlauslass the bore inlet sealingly contacted and offset with his arranged sealing inlet provides the necessary offset between the bore and seal inlet.

Due to this sealing element according to the invention, the bore can be drilled in the axial direction without a slope, so that the Manufacturing costs is reduced. Instead of a conventional O-ring as a seal, the sealing element according to the invention is now used, the sealing inlet has the necessary offset relative to its sealing outlet. As a result, in spite of the close to the cylinder wall extending through bore from the prior art, in particular from the DE 10 2010 031 664 Known, highly integrated concept for a pressurized fluid actuation unit can be used without the usual large manufacturing effort, so that the pressurized fluid actuation unit can be used in very small installation spaces.

According to a further advantageous embodiment, the sealing element is elastic, so that it is elastically adaptable to the bore inlet. However, it may be advantageous to make the sealing element less elastic, in particular at its sealing outlet. This can be prevented that the sealing element elastically expands when pressurized fluid into the bore and closes it.

According to a further advantageous embodiment, the pressure fluid actuation unit is connectable to a coupling housing section having a pressure fluid connection opening, in particular to a coupling-side transmission wall section, wherein the offset provided by the at least one sealing element is dimensioned such that an offset between the pressure fluid connection opening and the bore can be compensated.

To arrange the sealing element particularly well at the bore inlet can, as another advantageous embodiment shows, at the hole inlet a recess may be provided which is designed as a seal seat and at least partially receives the sealing element. As a result, the seal element can not slip during installation and the recess supports the staggered guidance of the pressurized fluid from the seal inlet to the seal outlet and thus to the bore inlet.

Advantageously, the recess depth can even be dimensioned such that the seal seat can be formed overall as a pressurized fluid passage.

According to a further advantageous embodiment, the pressure fluid actuation unit is adapted to actuate a double clutch, wherein the cylinder has two coaxially arranged actuating piston whose working spaces preferably overlap radially. In this case, the cylinder wall in each case has at least one bore for a pressurized fluid inlet which in each case extends from a bore inlet provided in the cylinder end side to a bore outlet opening into the working space for the respective actuating piston. According to the invention, the sealing element according to the invention is used on at least one of the bore inlets, which provides an offset of the seal inlet with respect to the associated bore in the cylinder wall.

The pressure fluid actuation unit according to the invention is particularly suitable for compressed air.

Another aspect of the present invention relates to a dual clutch for a motor vehicle, with such a pressure fluid actuation unit.

Further advantages and advantageous embodiments are defined in the claims, the drawings and the description.

In the following, the invention will be illustrated in more detail with reference to drawings. The embodiments illustrated in the drawings are purely exemplary in nature and do not specify the scope of protection of the application. This is defined solely by the appended claims.

Show it:

1 a schematic sectional view through a double clutch with inventive pressure fluid actuation unit;

2 : a sectional view through the in 1 illustrated Druckfluidbetätigungseinheit invention;

3 : A schematic view of a component of the pressure fluid actuation unit according to the invention 2 ;

4 : an enlarged section of the pressure fluid actuation unit according to the invention 2 , with the component of 3 ;

5 : an enlarged detail of the pressure fluid actuation unit according to the invention 2 ;

6 : A plan view of the pressure fluid actuation unit according to the invention 2 from transmission side; and

7 : an enlarged view of a detail of 6 ,

In the following, identical or functionally equivalent components are identified by the same reference numerals.

1 shows a schematic sectional view through a dual clutch assembly 10 , In this case, the illustrated double clutch arrangement comprises 10 essentially a double clutch 12 and a pressure fluid actuation unit according to the invention 14 ,

The double clutch 12 comprises two axially substantially adjacent coupling regions 16 . 18 , Both coupling areas 16 . 18 together is an intermediate plate 20 , with a motor side arranged connecting plate, not shown, on the one hand and a transmission side arranged housing 22 is firmly connected. The motor side arranged connecting plate is connected to a drive shaft (not shown), for example, a crankshaft of an internal combustion engine for common rotation about a rotation axis A or connect, wherein the connecting plate, the intermediate plate 20 and the case 22 essentially the input area of the double clutch 12 form.

The first coupling area 16 is of the normal-open type and includes one substantially between the intermediate plate 20 and the connecting plate, not shown, arranged first pressure plate 28 , The pressure plate 28 For example, with the connection plate and / or the intermediate plate 20 for common rotation about the axis of rotation A rotationally fixed, with respect to this, however, be held axially movable, and is biased for example by tangential leaf springs (not shown) or the like in the direction of disengagement. The first coupling area 16 has a first clutch disk assembly 30 on, their friction area 32 axially between the first pressure plate 28 and the intermediate plate 20 is held. Radially inside is the first clutch disk assembly 30 via a torsional vibration damper assembly 34 with a radially inner first transmission input shaft 36 rotatably coupled in a known manner.

To operate the first coupling area is a lever ring 56 provided, the radially outside a power transmission ring 58 loaded and radially inward on the housing 22 supported. The lever ring 56 is biased in a direction in which it has no force on the power transmission ring 58 exercises. Radially within contacted the lever ring 56 the pressure fluid actuation unit 14 ,

The second coupling area 18 is of the normally-closed type and includes one on the other transmission-side axial side of the intermediate plate 20 arranged pressure plate 38 and a second clutch disk assembly 40 whose friction area 42 between the second pressure plate 38 and the intermediate plate 20 is held. Also the second clutch disc assembly 40 includes a torsional vibration damper assembly 44 and is in its radially inner region with a first transmission input shaft 36 coaxially surrounding radially outer second transmission input shaft 46 coupled for common rotation in a known manner. The second pressure plate 38 is regarding the intermediate plate 20 and the housing 22 rotatably held, but axially movable and by means of a diaphragm spring 48 , which are located on the transmission side of the second pressure plate 38 and motor side of the housing 22 supports, biased towards engagement.

To the second pressure plate 38 disengage, are the radially inwardly extending spring tongues of the diaphragm spring 48 pulled towards the gear, causing the diaphragm spring 48 by the support radially on the outside of the housing 22 in its radially central region in the axial direction of the second pressure plate 38 moved away. This may cause the second pressure plate 38 also in the direction of the intermediate plate 20 move away.

To actuate the dual clutch is the pressurized fluid actuator assembly 14 formed so that it on the radially inner region of the lever ring 56 pushes and on the radially inner region of the diaphragm spring 48 draws. This is the first coupling area 16 engaged while the second clutch area 18 is disengaged.

As 1 and detailed 2 it can be seen, has the Druckfluidbetätigungsanordnung 14 as essential components an annular cylinder 68 and two coaxial with the axis of rotation A and the cylinder 68 arranged and on the cylinder 68 fluid-tight displaceable guided annular actuating piston 70 and 72 , of which the first actuating piston 70 for actuating the first coupling region 16 serves and the second actuating piston 72 for actuating the second coupling region 18 serves.

The cylinder 68 includes a radially outer annular cylinder wall 74 , an annular radially inner cylinder wall 76 , and one the radially outer cylinder wall 74 and the radially inner cylinder wall 76 radially connecting connecting wall 78 on. The cylinder walls form 74 . 76 . 78 a pocket 80 made, which is designed for the second actuating piston 72 take. The radially inner cylinder wall 76 is provided at its gear-side end with a radially inwardly facing projection whose end with a groove for receiving a sealing ring 81 , in particular lip seal ring is provided.

The first actuating piston 70 includes a radially outer in an axial direction concentric with the axis of rotation A extending piston section 82 and a radially inward of the radially outer piston portion 82 coaxial with this and the axis of rotation A extending radially inner piston portion 84 , which at their respective coupling-side end in the radial direction through a piston head 86 are connected. The piston bottom 86 extends radially inwardly beyond the clutch-side end of the radially inner piston portion 84 and is at its radially inner end with a radially inward and in the axial direction of the double clutch 12 open recess 88 for receiving one on the lever ring 56 acting engine-side actuating bearing 90 provided, which in the recess 88 in the axial direction by means of a securing ring 92 is fixed.

To jump out of the circlip 92 To prevent its groove, is also a bearing mounting by means of a plate spring 94 provided with integrated circlip attachment, which as a separate element in 3 and in their mounting position in the enlarged view of 4 is shown. As 3 shows, the plate spring 94 long tongues 96 and short tongues 98 on. The long tongues 96 are like 4a shows shaped so that they the locking ring 92 radially while the short tongues 98 radially inside the locking ring 92 are arranged. The long tongues 96 hold the retaining ring 92 axially in the groove, while the short tongues 98 (please refer 4b ) the circlip 92 supported against movement radially inward, causing the retaining ring 92 is secured in the groove.

Similar to the first actuating piston 70 also has the second actuating piston 72 two in a radial direction opposite piston portions, namely a substantially in an axial direction concentric with the axis of rotation A extending radially outer piston portion 102 and a radially inner piston portion also extending substantially in an axial direction concentric with the axis of rotation A. 104 , the transmission side by a extending in a radial direction piston crown 106 are connected.

The radially inner piston section 104 has a gearbox side and radially inwardly open recess 108 on, for receiving a transmission-side actuating bearing 110 serves. The actuation bearing 110 is designed for the diaphragm spring 48 act. It is on his inner ring 111 rotatably with a sleeve 112 provided, the diaphragm spring at its coupling end 48 engages behind and is in operative connection with her. To the sleeve 112 with the diaphragm spring 48 to bring into operative connection, the second actuating piston 72 moves against its normal direction of movement in the direction of the clutch, so that the coupling-side edge of the sleeve by the spring tongues of the diaphragm spring 48 is pressed. During this movement, it may happen that the inner ring 111 and the outer ring 113 of the actuating bearing 110 detach each other so that the actuator bearing 110 goes out of his operative connection. To prevent such behavior is a snap ring 114 provided, which is the actuation bearing 110 axially fixed in position.

2 and enlarged 5 continue to show that the first actuating piston 70 the coupling-side end of the annular cylinder 68 encloses to between the first actuating piston 70 and coupling-side connection wall 76 of the cylinder 68 a first workroom 118 form for receiving pressurized fluid. The radial outer side of the cylinder wall is used 74 as a running surface for the radially outer piston section 84 of the first actuating piston 70 , wherein a plurality of axially displaced sliding bearing elements 120 and a sealing element 122 a fluid-tight displaceability of the actuating piston 70 on the cylinder wall 74 guarantee. The sliding bearing elements 120 and the sealing element 122 , are preferably in respective ones on the inner periphery of the radially outer piston portion 82 trained grooves added.

Radial inside is the working space 118 of the first actuating piston 70 by means of a sealing ring 124 located in one in the radially inner piston section 84 trained groove is received, sealed fluid-tight but displaceable.

In contrast to the first actuating piston 70 is the second actuating piston 72 with its radially outer piston portion 102 on the radial inside of the cylinder 74 with the interposition of several sliding bearing elements 126 and a sealing ring 128 guided in a fluid-tight manner. The sliding bearing elements 126 and the sealing ring 128 are arranged in grooves, each in the outer periphery of the radially outer piston portion 102 of the second actuating piston 72 are formed. In addition, the second actuating piston is located 72 with its radially inner piston portion 104 with the interposition of the sealing ring 81 fluid-tightly displaceable on the radially inner cylinder wall 76 to one of the second actuating piston 72 , the radially outer cylinder wall 74 and the radially inner cylinder wall 78 limited second workspace 130 sealed fluid-tight.

The first workroom 118 will have an in 5 shown, a pressure fluid channel forming first bore 132 supplied with pressurized fluid. The hole 132 extends from a transmission-side bore inlet 134 in the axial direction inside the cylinder wall 74 to coupling-side connecting wall 76 of the cylinder 68 and flows with its bore outlet 135 in the first actuation chamber 118 ,

Analog becomes the second workspace 130 supplied via a not shown in the figures second bore with pressurized fluid, which is also in the axial direction in the interior of the cylinder wall 74 up to the coupling side connecting wall 76 extends, but does not pierce. Instead, allows a radially inwardly facing passage through the cylinder wall 74 (not shown) the supply of the second working space 130 with pressurized fluid.

According to the invention, both are preferably in the cylinder wall 74 trained holes 132 axially straight-drilled and have at their gear-side bore inlet 134 a seal 136 on. The seal 136 is in the illustrated embodiment in a recess 138 received in the transmission side radially outwardly extending cylinder wall portion 79 of the cylinder 68 is trained.

The seal 136 has a sealing inlet 140 and a sealing outlet 142 on, with the seal inlet 140 relative to the seal outlet 142 offset radially outward. The seal inlet 140 is how in 5 shown with a pressure fluid supply 144 in fluid contact to pressurized fluid from a pressurized fluid supply unit (not shown) into the pressurized fluid actuation unit 14 initiate. The seal outlet 142 however, is sealing with the bore 132 connected so that the pressurized fluid above the offset provided by the seal into the bore 132 and thus also in the workspace 118 can be introduced.

Since the offset according to the invention by the seal 136 is provided, and not as known in the art via an oblique bore, the manufacturing cost is significantly reduced.

The seal according to the invention 136 is preferably made of an elastic material, so that the seal 136 easy in the recess 138 is customizable. Optionally, the seal 136 in one area 146 with which the seal 136 the hole 132 Covered, in particular in its edge region, have a harder or stiffened area to prevent them from being elastic in the bore 132 expands. 5 further shows that in the cylinder 68 trained recess 138 and the seal 136 may be formed such that between seal 136 and recess 138 a gap 148 remains, which is designed as a pressure fluid passage. Alternatively, the Druckfluidpassage also directly from the seal 136 be educated.

Advantageously, the seal 136 also have a rim (not shown), which covers the recess and the seal 136 saved from slipping into the recess. It can be the edge, like the area 146 , Also be made of a material that is less elastic than the rest of the material of the seal. This prevents in particular that the seal slips when exposed to a pressurized fluid in the recess and a seal between the cylinder 68 and one the cylinder 68 contacting gear housing (not shown) is no longer provided.

6 shows a view of the in 1 and 2 illustrated actuating unit 14 from the transmission side, being significantly different from the seals 136 provided offset between gasket inlet 140 and sealing outlet 142 you can see. Furthermore is 6 to take that seal 136 a border area 150 that has the recess 138 covered. Also well illustrated is the offset between the gasket inlet 140 and sealing outlet 142 , wherein the seal outlet 142 at the same time as the inlet for the hole 132 is. As the enlarged view 7 it can be seen, is a distance D of the bore center to the cylinder wall 74 smaller than the radius A of the seal 136 even.

Referring again to 2 and 5 , it can be seen that it is possible by the inventive design, the bore 132 in the cylinder wall 74 completely drill through and seal, but at the same time ensure that cylinder 68 and pistons 72 remain mountable as the seal 136 not in the piston opening 154 of the cylinder 68 protrudes.

To prevent dirt from entering the area between the radially outer piston section 92 and the cylinder wall 74 To prevent radially outward is an annular cover 156 provided the cylinder 68 Coaxially surrounds.

At the radial inside of the pressurized fluid actuator assembly 14 The function of a dirt cover from the sleeve 112 accepted. To prevent dirt from entering a gap between the sleeve 112 and transmission input shaft 46 to prevent is radially inward on the sleeve 112 a dirt scraper 158 intended. As it is at the dirt scraper 158 is not a seal in the conventional sense, the material can be deliberately chosen so that it is due to the relative movement of sleeve 112 and transmission input shaft 46 can work so that the game is just big enough to hold back dirt, but the friction is not too big.

Preferably, this is in the workrooms 118 and 130 introduced pressurized fluid compressed air, which, for example, from a pressure accumulator, fed by a compressor, and under the control of a compressed air valve can be fed.

By the present invention, a Druckfluidbetätigungsanordnung or a double clutch equipped with it is provided, which ensures a compact and compact size reliable and defined operation of the two coupling portions of a double clutch. As the supply of work spaces 118 and 130 with pressurized fluid through drilled holes 132 takes place, however, the necessary offset via the seal according to the invention 136 is provided, the assembly and production costs are significantly reduced.

LIST OF REFERENCE NUMBERS

10

Dual clutch assembly

12

Double coupling

14

Pressure fluid actuator

16, 18

clutch areas

20

intermediate plate

22

casing

28

pressure plate

30

Clutch disk assembly

32

friction

34

torsional vibration damper

36

Transmission input shaft

38

pressure plate

40

Clutch disk assembly

44

torsional vibration damper

46

second transmission input shaft

48

diaphragm spring

56

lever ring

58

Power transmission ring

68

cylinder

70, 72

actuating piston

74

radially outer cylinder wall

76

radially inner cylinder wall

78

radial connecting wall

80

bag

81

poetry

82

radially outer piston section

84

radially inner piston section

86

piston crown

88

recess

90

operation seat

92

circlip

94

Belleville spring

96

long plate spring tongues

98

short plate spring tongues

102

outer piston section

104

inner piston section

106

piston crown

108

recess

110

operation seat

111

Inner ring of the actuating bearing

112

shell

113

Outer ring of the actuating bearing

114

circlip

118

working space

120

bearings

122

poetry

124

poetry

126

bearings

128

poetry

130

working space

132

first hole

134

hole inlet

135

bore outlet

136

sealing element

138

recess

140

seal inlet

142

Dichtungsauslass

144

Pressure fluid supply

146

less elastic range

148

gap

150

border area

154

Opening in the cylinder

156

cover

158

wipers

Claims (11)

Pressure fluid actuation unit ( 14 ) for a clutch arrangement, in particular for a double clutch ( 12 ) of a motor vehicle, with a cylinder ( 68 ) and at least one in the cylinder ( 68 ) fluid-tight displaceable guided actuating piston ( 70 ; 72 ), whereby the cylinder ( 68 ) in its cylinder wall ( 74 ) at least one bore ( 132 ) for a pressurized fluid extending from one in the cylinder face ( 79 ) bore inlet ( 134 ) to a bore outlet ( 135 ), wherein the bore outlet ( 135 ) in a designed for receiving the pressurized working space ( 118 ; 130 ) for the actuating piston ( 70 ; 72 ), so that with the bore ( 132 ) a fluidic connection between a pressurized fluid supply unit and the working space ( 118 ; 130 ), whereby the bore ( 132 ) and a pressurized fluid supply ( 144 ) have an offset, characterized in that at the bore inlet ( 134 ) at least one sealing element ( 136 ) with a sealing inlet ( 140 ) and a sealing outlet ( 142 ), wherein the sealing element ( 136 ) between its sealing inlet ( 140 ) and its sealing outlet ( 142 ) provides an offset, which is provided with its sealing outlet ( 142 ) the bore inlet ( 134 ) sealingly contacted and with his to Dichtungsauslass ( 142 ) arranged offset sealing inlet ( 140 ) an offset with respect to the bore ( 132 ) in the cylinder wall ( 74 ), wherein on the one hand the sealing inlet ( 140 ) with the pressure fluid supply ( 144 ) in fluid contact and on the other hand, the sealing outlet ( 142 ) sealing with the bore ( 132 ) connected is. Pressure fluid actuation unit ( 14 ) according to claim 1, wherein the sealing element ( 136 ) is elastic. Pressure fluid actuation unit ( 14 ) according to claim 2, wherein the sealing element ( 136 ), in particular at its sealing outlet ( 142 ), an area ( 148 ), in particular has an edge region which is less elastic than the rest of the sealing element ( 136 ). Pressure fluid actuation unit ( 14 ) according to one of claims 1 to 3, wherein the pressure fluid actuation unit ( 14 ) is connectable to a coupling housing section having at least one pressure fluid connection opening, in particular to a coupling-side transmission wall section, and that of the at least one sealing element ( 136 ) offset is dimensioned such that an offset between the pressure fluid port and the bore ( 132 ) is compensable. Pressure fluid actuation unit ( 14 ) according to one of claims 1 to 4, wherein at the bore inlet ( 134 ) a recess ( 138 ) is provided, which is designed as a sealing seat and the sealing element ( 136 ) at least partially absorbs. Pressure fluid actuation unit ( 14 ) according to claim 5, wherein the recess depth is dimensioned such that the seal seat can be formed as Druckfluiddurchlass. Pressure fluid actuation unit ( 14 ) according to one of the preceding claims with a sealing element ( 136 ) according to claim 3, wherein the sealing element ( 136 ) is adapted to the bore inlet ( 134 ) and / or the recess ( 138 ) To cover with the less elastic trained area. Pressure fluid actuation unit ( 14 ) according to one of claims 1 to 7, wherein a radial distance (D) of an axial center axis of the bore ( 132 ) to the cylinder wall ( 74 ) is smaller than a radial dimension (A) of the sealing element ( 136 ). Pressure fluid actuation unit ( 14 ) according to one of claims 1 to 8, wherein the pressure fluid actuation unit ( 14 ) is designed to have a double clutch ( 12 ) and the cylinder ( 68 ) two coaxially arranged actuating pistons ( 70 ; 72 ) whose working spaces ( 118 ; 130 ) preferably radially overlap, wherein the cylinder wall ( 74 ) at least one bore ( 132 ) for a pressurized fluid, each of which is provided by a provided in the cylinder end side bore inlet ( 134 ) to one in the respective work space ( 118 ; 130 ) for the respective actuating piston ( 70 ; 72 ) bore outlet ( 135 ), wherein at least one of the bore inlets ( 143 ) a sealing element ( 136 ) with a sealing inlet ( 140 ), which is an offset of the gasket inlet ( 140 ) with respect to the associated bore ( 132 ) in the cylinder wall ( 74 ). Pressure fluid actuation unit ( 14 ) according to one of claims 1 to 9, wherein the pressurized fluid is compressed air. Double coupling ( 12 ), in particular for a motor vehicle, with a pressure fluid actuation unit ( 14 ) according to one of claims 1 to 10.

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