Release device for a clutch

Abstract

Release device (105) for a clutch (100) with a rotational axis (110), the release device (105) comprising: - a rotatable component (115) with a hollow cylindrical end portion (120); - a hydraulic piston (145) which is axially movable relative to a radially outer surface (125) of the end portion (120) for defining a hydraulic working chamber (170); - a support element (135) attached to the rotatable component (115); - an elastic element (150) for providing an axial spreading force between the support element (135) and the piston (145) in order to reduce the hydraulic working space (170); wherein - the support element (135) comprises a radial portion (160) for axial engagement with the elastic element (150) and an axial portion (155) for radial engagement with a radially inner surface (130) of the end portion (120) of the rotatable component (115), - wherein the support element (135) is held on the rotatable component (115) in the axial direction by means of a positive locking element (140).

Description

[0001] The invention relates to a clutch release device. In particular, the invention relates to a hydraulic clutch release device, for example, in a drive train of a motor vehicle.

[0002] A clutch in a motor vehicle drivetrain is designed to transmit torque, particularly provided by a drive engine, to a downstream component such as a transmission or to decouple it from it. For this purpose, the clutch can be actuated to varying degrees. In one embodiment, the clutch engages gradually with increasing force the greater the degree of actuation. For this purpose, a first friction disc, connected to the input side of the clutch, is pressed axially against a second friction disc, connected to the output side of the clutch.

[0003] In a hydraulically actuated clutch, a hydraulic working chamber may be provided, which is closed on one axial side by a piston acting axially on one of the friction discs. Furthermore, an axially acting spring is provided to push the piston back to its original position and reduce the hydraulic volume in the working chamber when actuation decreases and the hydraulic pressure in the working chamber drops.

[0004] In one embodiment, which is particularly frequently used on a dual clutch, the piston is mounted concentrically to a rotating component, whereby the rotating component also forms part of the boundary of the hydraulic working chamber. The hydraulic working chamber is in the shape of a ring or torus. To mount the piston to the rotating component, it is usually pushed axially onto one end of the rotating component. The axially acting spring can also be mounted axially and supported on a support element, which is then attached to the rotating component.

[0005] Typically, the support element is welded to the rotating component. This welding process is relatively complex and costly. Furthermore, the support element is then firmly bonded to the rotating component and cannot be removed without causing damage.

[0006] As prior art, reference is made to EP 0 762 004 A2, US 5 172 799 A and JP 2008 - 256 056 A, each of which discloses release devices with a piston, a support element and an elastic element.

[0007] The invention is based on the object of providing a clutch release device that can be easily assembled and disassembled without causing damage. The invention achieves this object by means of a release device having the features of the independent claim. Subclaims specify preferred embodiments.

[0008] A release device for a clutch with a rotational axis comprises a rotatable component with a hollow cylindrical section, a hydraulic piston that is axially movable relative to a radially outer surface of the end section for defining a hydraulic working chamber, a support element attached to the rotatable component, and an elastic element for providing an axial spreading force between the support element and the piston in order to reduce the hydraulic working chamber. The support element comprises a radial section for axial contact with the elastic element and an axial section for radial contact with a radially inner surface of the end section of the rotatable component. The support element is held in the axial direction on the rotatable component by means of a positive locking element.

[0009] By providing a positive-locking connection instead of a material-locking connection between the support element and the rotating component, both simple assembly and non-destructive disassembly of the support element can be ensured. The available installation space can be optimally utilized, and production and assembly costs can be reduced. In particular, an otherwise unused interior space of the hollow cylindrical section can be utilized. The axial position of the support element relative to the rotating component can be precisely determined, so that the spring force of the elastic element is always predictable. The clutch can therefore be actuated with great precision. The release device is particularly advantageous for use with a dual clutch.

[0010] Preferably, the support element has a first radial recess in the axial section. Furthermore, the rotatable component has a second radial recess on the radial inner side, and the securing element extends radially through the first recess into the second recess.

[0011] In this way, the position of the locking element can be independent of the position and extent of the hydraulic working chamber. This can result in a greater usable piston travel. The locking element, which runs through the radial recesses, can precisely and reliably define the axial position of the support element on the rotating component.

[0012] In one embodiment, the second recess comprises a circumferential groove. The circumferential groove can be incorporated into the rotatable component with little effort. Furthermore, the circumferential groove can allow the support element to be rotated relative to the rotatable component. This can be advantageous, for example, for assembly or disassembly purposes.

[0013] Preferably, a plurality of first recesses are provided, with the securing element extending through several of the first recesses. This allows the axial load to be better distributed between the support element and the rotatable component.

[0014] In one embodiment, the first recesses are distributed circumferentially around the rotation axis. A uniform distribution is particularly advantageous in order to achieve a good distribution of the axial forces. It is particularly preferred that three first recesses are provided, which are evenly distributed around the rotation axis, with the securing element extending through all three first recesses into one or more second recesses in the rotatable component.

[0015] The securing element preferably comprises a flat retaining ring. Due to its flat shape, the retaining ring can be easily manufactured. Furthermore, it can be relatively narrow in the axial direction, since the shear forces occurring in the region of the first and second recesses are relatively low due to short levers. The retaining element can thus exhibit high radial stability, allowing it to securely hold the support element to the hollow cylindrical section of the rotatable component.

[0016] The retaining ring can have a uniform distance between its radially inner and outer boundaries. Deforming the retaining ring in the axial direction to attach or detach the retaining ring to the support element and the rotating component can therefore require a more easily predeterminable deformation force. This prevents unintentional release of the retaining element.

[0017] In a preferred embodiment, the retaining ring has a circular basic shape with one or more radially outwardly extending bulges for engaging the first and second recesses. Sections between the bulges or first recesses of the support element can thus be designed to save space, while the bulges can be shaped to allow relatively simple mounting of the retaining ring on the first recesses.

[0018] Preferably, the retaining ring has a radially extending parting line. In other words, the retaining ring is not completely closed at one point. This can reduce radial tension on the retaining ring, improving its assembly and disassembly.

[0019] The retaining ring can be manufactured by stamping from a flat sheet of metal. This allows the retaining ring to be manufactured cost-effectively using a process suitable for mass production.

[0020] The invention will now be described in more detail with reference to the accompanying figures, in which: Fig. 1 is a schematic sectional view of part of a clutch with hydraulic release device; Fig. 2 a two-side view of an embodiment of a support element of the release device of Fig. 1, and Fig. 3 a plan view of an exemplary securing element of the release device of Fig. 1represents.

[0021] Fig. 1 shows a schematic sectional view of a portion of a clutch 100 with a hydraulic release device 105. Both the clutch 100 and the hydraulic release device 105 are rotatably mounted about a rotational axis 110. The release device 105 comprises a rotatable component 115, which can be designed in particular as a stub shaft or hub, with a hollow cylindrical end section 120. A radially outer surface 125 and a radially inner surface 130 are located in the region of the end section 120. The hydraulic release device 105 further comprises a support element 135, a securing element 140, a hydraulic piston 145, and an elastic element 150.

[0022] The support element 135 comprises an axial section 155, the radial outer side of which rests against the radial inner surface 130 of the end section 120, and a radial section 160, which extends radially beyond the end section 120. The elastic element 150 is mounted between the piston 145 and the radial section of the support element 135. The piston 145 is preferably sealed from the outer surface 125 of the cylindrical section 120 by means of a seal 165. The piston 145 defines a hydraulic working chamber 170, which in the present embodiment is further defined by the rotatable component 115. If a fluid under pressure enters the hydraulic working chamber 170, the piston 145 is moved against the force of the elastic element 150 in the illustration of Fig. 1 is pressed to the right, thereby increasing or decreasing the axial contact force of friction discs (not shown) of clutch 100. If the pressure in the hydraulic working chamber 170 drops, the elastic element 150 pushes the piston 145 back, so that the working chamber 170 is reduced. The clutch actuation is thereby reduced again.

[0023] The elastic element 150 provides a spreading force between the piston 145 and the support element 135. Therefore, the elastic element 150 preferably comprises a compression spring. The support element 135 is held in the axial direction on the rotatable component 115 by means of the securing element 140 in the region of its axial section 155. For this purpose, the support element 135 has a first radial recess 175 in the region of its axial section 155, and the rotatable component 115 has a second radial recess 180 in the region of its hollow cylindrical end section 120. Several radial recesses 180 can be provided, or the second radial recess 180 can be designed in the form of a radial groove. The securing element 140 extends in the radial direction through the first recess 175 and into the second recess 180.

[0024] If the elastic element 150 is compressed, the securing element 140 is subjected to shear stress between the first recess 175 and the second recess 180. Since the boundaries of the recesses 175, 180 are preferably aligned with one another in the axial direction relative to the rotation axis 110, the effective levers for this stress on the securing element 140 are small, so that the securing element 140 is not subjected to significant stress.

[0025] Fig. Figure 2 shows a two-side view of an embodiment of the support element 135 of the release device 105 of Fig. 1. The left-hand section shows a longitudinal section along the rotation axis 110, and the right-hand section shows a top view. In the illustrated embodiment, a plurality of first recesses 175 are provided, which are preferably arranged on a circumference around the rotation axis 110 and more preferably are evenly distributed. In the present case, three first recesses 175 are provided, which are offset from one another by 120° with respect to the rotation axis 110. In further embodiments, more than three first recesses 175 are also possible. The first recesses 175 can be of the same or different shapes and have the same or different lengths and relative distances from one another.The number of first recesses 175 is not fundamentally limited, but it is recommended to provide sufficient material of the support element 135 between adjacent first recesses 175 in order to ensure axial load-bearing capacity of the axial section 155, in particular under extension.

[0026] Fig. 3 shows a plan view of an exemplary securing element of the release device 105 of Fig. 1. The illustrated embodiment can be used in particular with the Fig. 2 illustrated embodiment of the support element 135 with three evenly offset first recesses 175 can be used on the hydraulic release device 105.

[0027] The securing element 140 can preferably be manufactured from a flat sheet metal, in particular by stamping. In another embodiment, the securing element 140 can also be formed, for example, from a bent wire.

[0028] Preferably, the securing element 140 has a radial parting line 305. The shape of the securing element 140 results from a circular basic shape 310 around the rotation axis 110. Starting from the basic shape 310, one or more, in the illustration of Fig. 3 three bulges 315 are provided, which are designed to extend through the first recesses 175 into the second recesses 180 when the securing element 140 on the hydraulic release device 105 of Fig. 1 is attached.

[0029] Preferably, a distance between an inner boundary 320 and an outer boundary 325 of the securing element 140 is substantially uniform. List of reference symbols 100 clutch 105 hydraulic release device 110 axis of rotation 115 rotating component 120 hollow cylindrical end section 125 radial outer surface 130 radial inner surface 135 Support element 140 securing element 145 hydraulic piston 150 elastic element 155 axial section 160 radial section 165 Seal 170 hydraulic working space 175 first radial recess 180 second radial recess 305 Separation joint 310 circular basic shape 315 bulge 320 inner boundary 325 outer boundary

Claims

[1] Release device (105) for a clutch (100) with a rotational axis (110), the release device (105) comprising: - a rotatable component (115) with a hollow cylindrical end portion (120); - a hydraulic piston (145) which is axially movable relative to a radially outer surface (125) of the end portion (120) for defining a hydraulic working chamber (170); - a support element (135) attached to the rotatable component (115); - an elastic element (150) for providing an axial spreading force between the support element (135) and the piston (145) in order to reduce the hydraulic working space (170); wherein - the support element (135) comprises a radial portion (160) for axial engagement with the elastic element (150) and an axial portion (155) for radial engagement with a radially inner surface (130) of the end portion (120) of the rotatable component (115), - wherein the support element (135) is held on the rotatable component (115) in the axial direction by means of a positive locking element (140). [2] Release device (105) according to claim 1, wherein the support element (135) has a first radial recess (175) in the axial section (155) and the rotatable component (115) has a second radial recess (180) on the radial inner side (130) and the securing element (140) extends in the radial direction through the first recess (175) into the second recess (180). [3] Release device (105) according to claim 2, wherein the second recess (180) comprises a circumferential groove. [4] Release device (105) according to claim 2 or 3, wherein a plurality of first recesses (175) are provided and the securing element (140) extends through a plurality of the first recesses (175). [5] Release device (105) according to claim 4, wherein the first recesses (175) are distributed on a circumference around the axis of rotation (110). [6] Release device (105) according to one of the preceding claims, wherein the securing element (140) comprises a flat securing ring. [7] Release device (105) according to claim 6, wherein the retaining ring (140) has a uniform distance between its radially inner (320) and its radially outer boundary (325). [8] Release device (105) according to claim 6 or 7, wherein the retaining ring (140) has a circular basic shape (310) with one or more radially outwardly extending bulges (315) for immersing into the recesses (175, 180). [9] Release device (105) according to one of claims 6 to 8, wherein the retaining ring (140) has a parting line (305) extending in the radial direction. [10] Release device (105) according to one of the preceding claims, wherein the retaining ring (140) can be produced by punching from a flat sheet metal.

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