Hydraulic release device for clutch assembly and clutch assembly having such release device

Abstract

The present invention relates to a release device (10) for a clutch device (100) of a motor vehicle (1), comprising: an annular piston (11) housed in an annular release device housing (12) such that it can slide axially relative to the central axis Z of the release device housing (12) when hydraulic pressure is applied, wherein the annular piston (11) has a radially inner surface (11a) and a radially outer surface (11b), wherein the radially outer surface (11b) is adjacent to the annular release device housing (12) and is sealed relative to the annular release device housing (12) by means of a first groove seal (13) and a second groove seal (14), wherein an inlet opening (12a) for hydraulic fluid to pass through is provided in the release device housing (12), wherein the inlet opening (12a) is arranged between the first groove seal (13) and the second groove seal (14). The first groove seal (13) and the second groove seal (14) act on the radial outer surface (11b) of the annular piston (11) and together with the outer surface (11b) and the separator housing (12), define a pressure chamber (12b) for hydraulic fluid.

Description

Technical Field

[0001] The present invention relates to a hydraulic release device for driving a clutch device, particularly a release device for disengaging a clutch in a motor vehicle with hybrid or electric drive, and a clutch device having the release device. Background Technology

[0002] Disengagement clutches are used in both hybrid and electric vehicles to disconnect the electric motor from the internal combustion engine or for shifting gears in the electric motor. For the associated disengagement devices used to engage or disengage such clutches, the fault-free operation of the disengagement device is of particular importance for functional safety (FUSI). Furthermore, stringent environmental considerations must be taken into account; therefore, components of the disengagement clutch and disengagement device should be manufactured in a cost-effective and CO2-emission manner.

[0003] Clutch devices incorporating such disengagement clutches, for example, may be mounted in the wet chamber of a clutch, and typically consist of a closed release housing (often made of polymer), a piston, a grooved seal with a corresponding sheet metal retaining ring, an O-ring, and a release bearing with a gasket (also called a gasket disc). Similar to conventional hydraulic release devices, pressure is built up, causing the piston to move axially within the release housing, thereby actuating the disengagement clutch.

[0004] Such separation devices often encounter problems such as internal seal torsion, leakage, and pressure oscillation. Furthermore, these devices typically consist of numerous individual components, resulting in high manufacturing costs. Summary of the Invention

[0005] Therefore, one object of the present invention is to provide a separation device for a clutch, especially a disengagement clutch, which has fewer parts, can be manufactured at a lower cost, and has lower fault sensitivity.

[0006] According to the present invention, this objective is achieved by the separation device as described in claim 1 and the clutch device as described in claim 8. Preferred embodiments are given in the dependent claims.

[0007] A release device for a motor vehicle clutch assembly includes an annular piston housed within an annular release device housing in such a manner that it can slide axially relative to the central axis Z of the release device housing when hydraulic pressure is applied. The annular piston has a radially inner surface and a radially outer surface, wherein the radially outer surface is adjacent to the annular release device housing and is sealed relative to the annular release device housing by means of a first groove seal and a second groove seal. An inlet opening for hydraulic fluid passage is provided in the release device housing, wherein the inlet opening is arranged between the first groove seal and the second groove seal, and the first groove seal and the second groove seal act on the radially outer surface of the annular piston and, together with the release device housing, define a pressure chamber for the hydraulic fluid.

[0008] Generally speaking, it should be noted that, within the scope of this invention, when directional indicators such as “axial,” “radial,” or “circumferential” are used, unless otherwise stated, these indicators always refer to the central axis Z.

[0009] The separation device of the present invention extends annularly around a central axis Z. When the separation device is used to disengage a clutch, the central axis Z can coincide with the rotation axis of the clutch. The annular separation device housing, together with the radially outer surface of the annular piston and two groove seals, forms a pressure chamber for hydraulic fluid. Hydraulic fluid can flow into the pressure chamber through the inlet opening to allow the annular piston to move axially relative to the central axis Z. For this purpose, at least a portion of the radially outer surface of the annular piston is made flat in the axial direction.

[0010] Therefore, the pressure chamber is positioned laterally relative to the annular piston. This simplifies both the structure of the annular piston and the structure of the separator housing. The separator housing can be constructed with a smaller radial dimension relative to the central axis, thus saving materials and manufacturing costs.

[0011] The annular piston may have at least a first region having a first outer diameter D and a second region having a second outer diameter d, wherein the first outer diameter D is larger than the second outer diameter d. The first region may transition to the second region via a step or step. In this case, the step or step may include an edge, particularly a right angle, which can serve as a receiving seat for one of two groove seals. The first and second groove seals may be arranged in the first region, i.e., in the region with the smaller outer diameter. The second region D with the larger outer diameter forms a radially outward protrusion, where one of the groove seals can abut to define a pressure chamber. In particular, the annular piston can be formed solely by means of this step or step, thereby providing an annular piston that is very easy to manufacture.

[0012] According to one embodiment of the invention, the separator housing defines the annular piston only on its outer surface. In other words, the separator housing includes an annular wall but not a bottom wall extending substantially perpendicular to the central axis Z. Therefore, the separator housing is open on both end faces, i.e., on the sides extending perpendicular to the central axis Z, or is largely open (at least about 80% of the corresponding end face area). When the separator is driven, i.e., when the pressure chamber is filled with pressurized hydraulic fluid, the annular piston moves axially alongside the separator housing. In this way, while simplifying the separator housing structure, a separator structure that saves installation space, particularly in the radial direction, is achieved.

[0013] According to a further preferred embodiment of the invention, the inlet opening is configured as a pipe fitting, wherein the receiving portion for the first groove seal ring is defined axially by the pipe fitting. For the purposes of this invention, a "pipe fitting" refers to a short tubular supply portion leading to the pressure chamber. Preferably, the pipe fitting is integrally formed with the separation device housing. Furthermore, the pipe fitting is preferably radially extending, meaning that the central axis of the pipe fitting is perpendicular to the central axis Z. The pipe fitting, or one of its radial walls, may form part of the receiving portion for the first groove seal ring, for defining the pressure chamber in the axial direction.

[0014] During axial travel, the annular piston is movable relative to the first groove seal. This means that during axial movement of the annular piston, the first groove seal is fixed within its receiving portion, while the outer surface of the annular piston slides along the first groove seal. This embodiment further supports the simplicity of the annular piston structure.

[0015] According to another embodiment, the second groove seal ring may have a static sealing lip and a dynamic sealing lip, wherein the static sealing lip abuts against the radially outer surface of the annular piston, while the dynamic sealing lip abuts against the separator housing. In this embodiment, the second groove seal ring moves together with the annular piston during axial travel, wherein the dynamic sealing lip slides along the separator housing.

[0016] A radially inner shoulder may be formed on the radially inner surface of the annular piston, which serves as a support surface for the release bearing. The radially inner shoulder may be arranged at a right angle, forming a transition from a first region to a second region of the radially inner surface, wherein the first region abuts an axial end face of the annular piston and has a larger radius relative to the central axis than the second region.

[0017] The present invention also relates to a clutch device having a clutch and a release device according to at least one of the above embodiments, wherein the clutch is operatively connected to the release device via a release bearing. The clutch device further has an annular housing that at least partially surrounds and concentrically arranges the release device housing, wherein the annular housing and the radially outer side of the release device housing together form an external pressure chamber.

[0018] The phrase "at least partially enclosed" should be understood to mean that the annular housing of the clutch assembly has at least one recess, wherein the release device, i.e., the release device housing and the annular piston, is at least partially accommodated. In the clutch assembly of the present invention, the annular piston is surrounded by the release device housing in at least one axial segment on its outer surface, and the release device housing is in turn surrounded by the annular housing in at least one axial segment. These two housings can cooperate with each other to accommodate the release device.

[0019] The annular housing of the clutch assembly and the radially outer side of the release housing together form an external pressure chamber, which is located radially outside the pressure chamber formed by the outer surfaces of the release housing and the annular piston. Therefore, the pressure chamber of the release housing is equivalent to an internal pressure chamber. During clutch operation, pressurized hydraulic fluid flows from the external pressure chamber through an inlet opening in the release housing to the internal pressure chamber on the annular piston side. In other words, the inlet opening connects the external pressure chamber to the radially inner pressure chamber.

[0020] The clutch that is operationally connected to the release mechanism via a release bearing can be, for example, a multi-plate clutch. In particular, it can be a wet clutch mounted within a wet chamber including the release mechanism. It is well known that a wet clutch is part of the hydraulic circuit of the transmission to which it is mounted. In particular, this clutch can be a disengagement clutch in electric or hybrid vehicles.

[0021] According to one embodiment of the clutch device of the present invention, an inlet leading to an external pressure chamber is formed in the radially outer sidewall of the annular housing. This inlet forms an angle of 0° to 30° with the inlet opening of the separation device housing in the circumferential direction relative to the central axis Z. In other words, the inlet of the external pressure chamber is located near the inlet opening of the pressure chamber in the circumferential direction.

[0022] Furthermore, the inlet can also be at the same height or approximately the same height as the inlet opening in the axial direction. In other words, the central axis of the inlet opening or pipe fitting can coincide with the central axis of the inlet, or their axes can be parallel to each other, and preferably offset relative to each other only by a small distance in the axial direction. The inlet opening and the inlet are arranged radially opposite each other at least in a partial area via an internal pressure chamber. This allows for a shorter flow path for the hydraulic fluid.

[0023] The housing has an outer side wall, a bottom wall, and an inner side wall, wherein the outer side wall is connected to the inner side wall via the bottom wall, and the bottom wall abuts and rests against an axial end of the release device housing. This axial end is the axial end of the annular piston on the side away from the clutch. Unlike prior art, the axial end of the annular piston away from the clutch is not defined by the release device housing, but directly by the clutch assembly housing. Therefore, the release device housing itself can be constructed in a simple and low-material-consumption manner. The release device housing and the clutch assembly housing thus cooperate to hold the release device within the clutch assembly. Compared to prior art, fewer parts are required, thereby reducing manufacturing costs for the same function. Attached Figure Description

[0024] The invention will now be described in more detail with reference to a non-limiting embodiment in the accompanying drawings.

[0025] As shown in the attached figure: Figure 1 shows the basic structure of a clutch device with a release mechanism in a cross-sectional view according to the prior art; Figure 2 shows a clutch device in cross-sectional view according to an embodiment of the present invention; Figure 3a 3b represent the engagement and disengagement states, respectively. Figure 2 Cross-sectional views of the clutch assembly shown; Figure 4a 4b represent the engagement and disengagement states, respectively. Figure 2 Cross-sectional views of the separation device shown.

[0026] These figures are for illustrative purposes only and are intended to help understand the invention. Identical or similar elements are labeled with the same reference numerals. Detailed Implementation

[0027] exist Figure 1 In the middle, through dissection Figure 1 A clutch device 1 according to the prior art is shown. The clutch device 1 includes a clutch 2, an annular housing 3, and a disengagement device 10, which is at least partially housed in the housing 3. The clutch 2 is a disengagement clutch used in motor vehicles or electric vehicles with hybrid drive to disengage the electric motor from the internal combustion engine, or for shifting gears in pure electric vehicles.

[0028] The separation device 10 has a separation device housing 12 in which an annular piston 11 is movably housed, and the separation device housing 12 itself is mounted in an annular housing 3. The separation device housing 12 is sealed relative to the annular housing 3 by means of an O-ring 4. Since the clutch 2 in this embodiment is a wet-type disengagement clutch, the clutch 2 is located in a wet chamber 5, and the separation device 10 is also located in the wet chamber 5.

[0029] A pressure chamber 12b is formed within the separator housing 12, to which pressurized hydraulic fluid can be supplied through an inlet opening 12a. As can be seen, the pressure chamber 12b is sealed outwards (i.e., relative to the wet chamber 5) at the annular piston 11 and at the separator housing 12 by means of groove seals 13 and 14. Sheet metal retaining rings 16 are used to mechanically support the groove seals 13 and 14.

[0030] The annular housing 3, the annular piston 11 housed therein, and the separation device housing 12 extend in a ring around the central axis Z. When hydraulic fluid flows into the pressure chamber 12b through the inlet opening 12a, the annular piston 11 moves axially to the left relative to the central axis Z, corresponding to a stroke motion, and disengages the clutch 2. Once the clutch 2 is disengaged, the full torque of a motor (not shown in the figure) can be transmitted. When the hydraulic pressure in the pressure chamber 12b decreases again, the annular piston 11 returns to its initial position (to the right in the figure), and the clutch 2 disengages. In this position, no torque is transmitted. During this process, the clutch 2 pushes the annular piston 11 back to its initial position.

[0031] See now Figure 2 This describes an embodiment of a clutch device 1 according to the present invention, wherein the same components and functions are not discussed separately in detail.

[0032] The clutch device 1 according to the invention also includes a clutch 2, an annular housing 3, and a release device 10, in which an annular piston 11 is housed. The annular housing 3 can be made of metal (e.g., aluminum or steel), particularly a casting, while the release device housing 12 of the release device 10 can be made of polymer. Similar to the prior art, an O-ring 4 is provided between the release device housing 12 and the annular housing 3 to achieve a seal relative to the wet chamber 5.

[0033] Unlike existing technologies, in the clutch device 1 of the present invention, the pressure chamber 12b is arranged only on the side of the annular piston 11. The annular piston 11 has an inner surface 11a and an outer surface 11b, wherein the first groove seal ring 13 and the second groove seal ring 14 act on the radially outer surface 11b and together with the outer surface 11b and the radially outer surface 12d of the separation device housing 12, form the pressure chamber 12b. As can be seen, the inlet opening 12a leading to the pressure chamber 12b is here configured as a short pipe joint that extends into the pressure chamber 12b and is arranged axially between the first groove seal ring 13 and the second groove seal ring 14.

[0034] The separator housing 12 is significantly smaller than that of prior art separator housings, covering only the radially outer surface 11b of the annular piston 11. Thus, the separator housing 12 forms a bottomless, open housing. This results in a low-cost, material-saving clutch device 1 that requires minimal installation space.

[0035] See Figure 3a and Figure 3b They respectively illustrate the clutch device 1 according to the invention in the engaged state ( Figure 3a ) and in the separated state ( Figure 3b The sectional view below will provide a more detailed explanation of the clutch device 1 and its functions.

[0036] The annular housing 3 includes a radially outer sidewall 3c, a bottom wall 3d, and a radially inner sidewall 3e. An external pressure chamber 3a is formed between the separation device housing 12 and the radially outer sidewall 3c of the annular housing 3, with an inlet 3b opening that extends radially through the outer sidewall 3c of the annular housing 3. Figure 3a As shown, in the initial state, one axial end region 11g of the annular piston 11 is directly attached to the annular housing 3, that is, attached to its bottom wall 3d.

[0037] As from Figure 3a and Figure 3b As can be seen in the cross-sectional view, the inlet 3b is only slightly offset in the axial direction relative to the inlet opening 12a of the separation device housing 12, and is arranged at the same angle in the circumferential direction. Therefore, the inlet opening 12a and the inlet 3b are positioned corresponding to each other in some areas.

[0038] The annular piston 11 has at least a first region 11c having a first outer diameter D and a second region 11d having a second outer diameter d, wherein the first outer diameter D is larger than the second outer diameter d. The first region 11c transitions to the second region 11d at an outer shoulder 11e.

[0039] Figure 3b The representation of and Figure 3aThe difference lies in the representation of , Figure 3b The separation device 10 is in a separated state, wherein the annular piston 11 is relative to Figure 3a The diagram shows a leftward offset along the direction of the hollow arrow, thereby driving the clutch 2 via the release bearing 15. The release housing 12 still rests against the bottom wall 3d of the annular housing 3 with one axial end 12e, but the axial end region 11g of the annular piston 11 is now spaced apart from the bottom wall 3d.

[0040] See now Figure 4a and Figure 4b The separation device 10 of the present invention will be described in more detail below. As can be seen, first and second groove seals 13, 14 are arranged in the second region 11d of the annular piston 11. The outer shoulder 11e serves as a seat for the second groove seal 14, the latter having a static sealing lip 14a abutting against the annular piston 11 and a dynamic sealing lip 14b abutting against the separation device housing 12. The first groove seal 13 is received in the receiving portion 12c of the separation device housing 12. As can be seen, the inlet opening 12a of the separation device housing 12, which is configured as a tubular connector, forms a support wall for the first groove seal 13 (which is a static seal). The inner surface 11a of the annular piston 11 forms a radially inner shoulder 11f, which serves to form a support for the separation bearing 15.

[0041] exist Figure 4a In the middle, the separation device 10 is in the initial position, while Figure 4b In the middle, it is in the separated state, in which the annular piston 11 is displaced relative to the stroke H. As can be seen by comparing the two figures, during the movement of the annular piston 11, the first groove seal ring 13 remains in its position, while the second groove seal ring 14 is driven during the separation movement of the annular piston 11.

[0042] In summary, it should be noted that, in the embodiments according to the invention, the separator housing 12 is "divided," and thus "opened," compared to the prior art. The annular piston 11 is adapted to the available installation space and can be manufactured with a simple geometry. Since the first groove seal ring 13 is configured as a static seal, only one dynamic / moving seal exists, namely the second groove seal ring 14. The supply of hydraulic fluid remains substantially constant. Compared to the prior art, the installation space required for the separator is reduced, thereby further saving costs. Since a dynamic seal is not required on the radially inner surface 11a of the annular piston 11, problems such as inner seal torsion, which often occur in the prior art, are not present.

[0043] Explanation of reference numerals in the attached figures 1. Clutch device 2. Clutch 3. Shell 3a External pressure chamber 3b entrance 3c Lateral wall 3D bottom wall 3e Inner wall 4 O-rings 5 wet chamber 10 Separation device 11. Annular piston 11a Inner surface 11b Outer surface 11c First Region 11d Second Region 11e Outer shoulder 11f Inner shoulder 11g Axial end region 12 Separation device housing 12a Inlet opening 12b Pressure chamber 12c Retaining section 12d Radial outer side 12e Axial end 13 First Groove Sealing Ring 14 Second Groove Sealing Ring 14a Static sealing lip 14b Dynamic sealing lip 15 Separation bearing 16 Sheet metal retaining ring Z-axis D. Outer diameter of the first region d. Outer diameter of the second region.

Claims

1. A release device (10) for a clutch assembly (100) in a motor vehicle (1), comprising: An annular piston (11) is housed in an annular separator housing (12), thereby allowing it to slide axially relative to the central axis Z of the separator housing (12) when hydraulic pressure is applied. The annular piston (11) has a radially inner surface (11a) and a radially outer surface (11b). The radially outer surface (11b) is adjacent to the annular separation device housing (12) and is sealed relative to the annular separation device housing (12) by means of a first groove sealing ring (13) and a second groove sealing ring (14). The separation device housing (12) is provided with an inlet opening (12a) for hydraulic fluid to pass through. The inlet opening (12a) is arranged between the first groove sealing ring (13) and the second groove sealing ring (14). Its features are, The first groove seal (13) and the second groove seal (14) act on the radial outer surface (11b) of the annular piston (11) and together with the outer surface (11b) and the separation device housing (12), define a pressure chamber (12b) for the hydraulic fluid.

2. The separation device (10) according to claim 1, Its features are, The annular piston (11) has at least a first region (11c) with a first outer diameter D and a second region (11d) with a second outer diameter d. Wherein the first outer diameter D is greater than the second outer diameter d. The first region (11c) transitions to the second region (11d) via the outer shoulder (11e). Furthermore, the first and second groove sealing rings (13; 14) are disposed in the second region (11d).

3. The separation device (10) according to claim 1 or 2, Its features are, The housing (12) of the separation device is defined only on the outer surface (11b) of the annular piston (11).

4. The separation device (10) according to any one of the preceding claims, Its features are, The inlet opening (12a) is configured as a pipe fitting. The receiving portion (12c) for the first groove sealing ring (13) is defined by the pipe fitting in the axial direction.

5. The separation device (10) according to claim 4, Its features are, The annular piston (11) is movable relative to the first groove seal (13) during its axial stroke.

6. The separation device (10) according to any one of the preceding claims, Its features are, The second groove sealing ring (14) has a static sealing lip (14a) and a dynamic sealing lip (14b). The static sealing lip (14a) is attached to the radially outer surface (11b). The dynamic sealing lip (14b) abuts against the housing (12) of the separation device.

7. The separation device (10) according to any one of the preceding claims, Its features are, A radially inner shoulder (11f) is formed on the radially inner surface (11a) of the annular piston (11). It serves as the support surface for the release bearing (15).

8. A clutch device (1), comprising a clutch (2) and a disengagement device (10) according to any of the preceding claims, in, The clutch (2) is in working connection with the release device (10) via the release bearing (15). The clutch device (1) has an annular housing (3). The annular shell (3) at least partially surrounds and is concentrically arranged with the separation device shell (12). The annular shell (3) together with the radial outer side (12d) of the separation device shell (12) form an external pressure chamber (3a).

9. The clutch device (1) according to claim 8, Its features are, An inlet (3b) leading to the external pressure chamber (3a) is provided in the housing (3) through the outer side wall (3c) of the housing (3). Its angle with the inlet opening (12a) of the separation device housing (12) in the circumferential direction relative to the central axis Z is 0° to 30°.

10. The clutch device (1) according to claim 8, Its features are, The shell (3) has an outer side wall (3c), a bottom wall (3d), and an inner side wall (3e). The outer sidewall (3c) is connected to the inner sidewall (3e) via the bottom wall (3d). Furthermore, the bottom wall (3d) is adjacent to and abuts against the axial end (12e) of the housing (12) of the separation device.

Images