Clutch device with hydraulic release device

Abstract

The invention relates to a release device (10) for a clutch device (100) of a motor vehicle (1), comprising: an annular piston (11) which is accommodated in an annular release housing (12) such that it can slide in the axial direction with respect to a center axis Z of the release housing (12) when a hydraulic pressure is applied, wherein the annular piston (11) has a radially inner side surface (11a) and a radially outer side surface (11b), wherein the radially outer side surface (11b) adjoins the annular release housing (12) and is sealed against the annular release housing (12) by a first groove sealing ring (13) and a second groove sealing ring (14), wherein an inlet opening (12a) for the passage of hydraulic fluid is provided in the release housing (12), wherein the inlet opening (12a) is between the first groove sealing ring (13) and the second groove sealing ring (14) is positioned.The first groove sealing ring (13) and the second groove sealing ring (14) engage the radially outer side surface (11b) of the annular piston (11) and, together with the outer side surface (11b) and the release housing (12), delimit a pressure chamber (12b) for the hydraulic fluid.

Description

The invention relates to a hydraulic disengagement device for the actuation of a clutch device, in particular a separating clutch in a motor vehicle with a hybrid or electric drive, and to a clutch device with such a disengagement device.Separating clutches are used both in hybrid drives and in electric vehicles and serve for separating the electric motor from the internal combustion engine or for changing gears for electric motors. In associated disengagement devices for disengaging or engaging such a separating clutch, a perfect functionality of the disengagement device has a particular significance with regard to functional safety (FUSI). Furthermore, tight environmental aspects must also be taken into account, which is why components of the disconnect clutch and of the disconnect device should be produced cost-effectively and CO 2- arm.Clutch devices which contain such a separating clutch, which can be installed, for example, in a wet chamber of the clutch, are usually constructed from a closed clutch release housing, which is frequently produced from a polymer, pistons, groove sealing rings with associated sheet metal retaining ring, O-rings and a clutch release bearing with bearing disk (also referred to as shim disk). As in conventional hydraulic disengagement devices, a pressure build-up moves the piston axially in the disengagement housing and actuates the separating clutch in this case.In such disengagement devices, problems generally arise such as twisting of an inner seal, leakage and pressure oscillations. Moreover, the disengaging device is conventionally made up of numerous individual components, so that the production costs for producing such a disengaging device are high.It is therefore an object of the present invention to specify a disengagement device for a clutch, in particular a separating clutch, which has a reduced number of components, can be produced cost-effectively and has a low susceptibility to errors.This object is achieved according to the invention by a disengagement device according to claim 1 and a clutch device according to claim 8. Preferred embodiments are specified in the dependent claims.A clutch device for an automobile, a ring piston accommodated in an annular clutch housing so as to be slidable in an axial direction with respect to a center axis Z of the clutch housing upon application of a hydraulic pressure. The ring piston has a radially inner side surface and a radially outer side surface, wherein the radially outer side surface adjoins the annular release housing and is sealed against the annular release housing by a first groove sealing ring and a second groove sealing ring. An inlet opening is provided in the release housing for the passage of hydraulic fluid, wherein the inlet opening is positioned between the first groove sealing ring and the second groove sealing ring, and wherein the first groove sealing ring and the second groove sealing ring engage on the radially outer side surface of the ring piston and define a pressure chamber for the hydraulic fluid with the release housing.It should generally be noted that, within the scope of the present invention, if directional references such as "axial", "radial" or "circumferential" are used, these always relate to the central axis Z, unless otherwise stated.The disengagement device according to the invention extends annularly about the central axis Z, which can coincide with an axis of rotation of the clutch when the disengagement device is used in a separating clutch. The annular release housing, together with the radially outer side face of the annular piston and the two groove sealing rings, forms a pressure chamber for the hydraulic fluid, which can flow via the inlet opening into the pressure chamber in order to move the annular piston in the axial direction with respect to the central axis Z. For this purpose, at least a part of the radially outer side surface of the annular piston is configured to be planar in the axial direction.Thus, the pressure chamber is arranged purely laterally with respect to the ring piston. This simplifies both a construction of the annular piston and of the release housing. The clutch release housing can be formed with small radial dimensions with respect to the center axis, whereby both material and production costs can be saved.The annular piston can have at least a first region with a first outer diameter D and a second region with a second outer diameter d, wherein the first outer diameter D is greater than the second outer diameter d. The first region can merge into the second region via a shoulder or step. The shoulder or step can comprise an edge, in particular a right angle edge, which can serve as a receiving seat for one of the two groove sealing rings. The first and the second groove sealing ring can be arranged in the first region, i.e. in the region with a smaller outer diameter. The second region with the larger outer diameter D forms a projection radially outwards, against which one of the groove sealing rings can abut in order to delimit the pressure chamber. In particular, the annular piston can be formed with only this one shoulder or step, whereby an annular piston which is very simple to produce is provided.According to one embodiment of the invention, the release housing delimits the annular piston exclusively on its outer lateral surface. In other words, the release housing comprises an annular wall, but not a bottom wall, which extends substantially perpendicular to the central axis Z. This is thus a release housing which is open on both end sides, i.e. on the sides which run perpendicular to the central axis Z, or is open to a large extent (at least approximately 80% of the area of the respective end side). Upon actuation of the disengagement device, i.e. upon filling of the pressure chamber with pressurized hydraulic fluid, the ring piston moves in the axial direction next to the disengagement housing. This results in a construction of the disengaging device which is particularly space-saving, in particular in the radial direction, with simultaneously simplified construction of the disengaging housing.According to a further advantageous embodiment of the invention, the inlet opening is designed as a pipe socket, wherein a receptacle for the first groove sealing ring is delimited in an axial direction by the pipe socket. The term "pipe socket" in the context of the present invention means a short tubular feed line to the pressure chamber. Preferably, the pipe socket is formed integrally with the release housing. In addition, the pipe socket can preferably extend radially, which in this context means that a central axis of the pipe socket runs perpendicular to the central axis Z. The pipe socket or a radial wall thereof can be part of a receptacle for the first groove sealing ring, which receptacle serves to delimit the pressure chamber in an axial direction.The ring piston can be movable in the axial direction relative to the first groove sealing ring during a stroke movement. This means that the first groove sealing ring remains firmly in its receptacle during a movement of the annular piston in the axial direction and the outer side surface of the annular piston slides along the first groove sealing ring. This embodiment further assists the simplicity of the construction of the annular piston.According to a further embodiment, the second groove sealing ring can have a static sealing lip and a dynamic sealing lip, wherein the static sealing lip abuts the radially outer side surface of the ring piston and the dynamic sealing lip abuts the release housing. In this embodiment, the second grooved ring seal moves together with the ring piston during an axial stroke movement, wherein the dynamic sealing lip slides along the release housing.In this case, a radially inner shoulder can be formed on the radially inner side surface of the annular piston, which shoulder serves as a contact surface for a release bearing. The radially inner shoulder can be formed in particular at right angles, wherein it forms a transition from a first region of the radially inner side surface to a second region of the radially inner side surface, wherein the first region adjoins an axial end face of the annular piston and has a greater radius with respect to the central axis than the second region.The invention also relates to a clutch device which has a clutch and a disengagement device according to at least one of the preceding configurations, wherein the clutch is operatively connected to the disengagement device via a disengagement bearing. The clutch device also has an annular housing which at least partially surrounds the release housing and is arranged concentrically with respect thereto, wherein the annular housing forms an outer pressure chamber with a radial outer side of the release housing.The expression "at least partially encompasses" is to be understood to mean that the annular housing of the clutch device has at least one recess in which the disengagement device, i.e. the disengagement housing and the annular piston, are at least partially accommodated. In the clutch device according to the invention, the annular piston is surrounded on its outer side surface at least on an axial section by the release housing, which in turn is surrounded at least on an axial section by the annular housing. The two housings may cooperate to receive the release device.The annular housing of the clutch device forms, together with the radial outer side of the release housing, an outer pressure chamber which is arranged upstream of the pressure chamber which forms the release housing with the outer side surface of the annular piston in the radial direction. The pressure chamber of the release housing thus forms, as it were, an inner pressure chamber. During operation of the clutch device, hydraulic fluid flows under pressure from the outer pressure chamber via the inlet opening in the release housing to the inner pressure chamber on the side of the annular piston. In other words, the inlet opening leads from the outer pressure chamber to the radially inner pressure chamber.The clutch, which is operatively connected to the disengagement device via a disengagement bearing, can be, for example, a multiplate clutch. In particular, it can be a wet clutch which is accommodated in a wet chamber which also contains the disengagement device. As is well known, wet clutches are those that form part of a hydraulic circuit of a transmission in which they are installed. In particular, the clutch can be a separating clutch of an electric or hybrid vehicle.According to one embodiment of the clutch device according to the invention, an inlet is formed in the annular housing in a radially outer side wall to the outer pressure chamber, which inlet encloses an angle of between 0° and 30° with the inlet opening of the release housing in the circumferential direction with respect to the central axis Z. In other words, the inlet of the outer pressure chamber is located in the circumferential direction in the vicinity of the inlet opening of the pressure chamber.In addition, the inlet can also be arranged at the same height or approximately at the same height as the inlet opening in the axial direction. In other words, a central axis of the inlet opening or of the pipe socket can coincide with a central axis of the inlet or the two axes can be parallel to one another, wherein they are preferably offset from one another only by a small distance in the axial direction. The inlet opening and the inlet are radially opposite one another at least in sections across the inner pressure chamber. Thus, a flow path of the hydraulic fluid can be kept short.The housing has the 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 wherein the bottom wall abuts and abuts an axial end of the release housing. The axial end is an axial end of the annular piston remote from the clutch. Unlike in the prior art, the annular piston is therefore not limited at the axial end remote from the clutch by the release housing of the release device, but rather directly by the housing of the clutch device. Thus, the release housing itself can be formed simply and with little material use. The release housing and the housing of the clutch device thus cooperate to retain the release device in the clutch device. In comparison with the prior art, fewer components are required, as a result of which low costs are produced during production with the same function.The invention is explained in more detail below on the basis of a non-limiting exemplary embodiment with reference to the drawings.In the drawing, the following are shown: FIG. 1 shows a basic structure of a clutch device with a disengagement device according to the prior art in cross section; FIG. 2 shows a coupling device according to an embodiment of the invention in cross section; FIGS. 3 a, 3 b show respective cross-sectional views of the clutch device of FIG. 2 in the engaged and disengaged states, respectively; FIGS. 4 a, 4 b show respective cross-sectional views of the disengagement device of FIG. 2 in the engaged and disengaged states, respectively.The figures are merely schematic in nature and serve exclusively for understanding the invention. Identical or analogous elements are provided with the same reference numerals.In FIG. 1, a clutch device 1 according to the prior art is generally shown in a cross-sectional view. The clutch device 1 comprises a clutch 2, an annular housing 3 and a disengagement device 10, which is at least partially accommodated in the housing 3. The clutch 2 is a separating clutch, as is used in hybrid motor vehicles or in electric vehicles, in order to separate an electric motor from an internal combustion engine, or in order to enable a gear change in a pure electric vehicle.The disengaging device 10 has a disengaging housing 12 in which an annular piston 11 is accommodated in a displaceable manner and which in turn is seated in the annular housing 3. The release housing 12 is sealed by O-rings 4 on the annular housing 3. Since the clutch 2 of the present embodiment is a wet disconnect clutch, the clutch 2 is located in a wet room 5 in which the release device 10 is also located.A pressure chamber 12 bis formed in the release housing 12 and hydraulic fluid under pressure can be supplied to said pressure chamber via an inlet opening 12 a. As can be seen, the pressure chamber 12 bis sealed off from the outside, i.e. from the wet chamber 5, on the annular piston 11 and on the releaser housing 12 via groove sealing rings 13, 14. To mechanically support the groove sealing rings 13, 14, sheet metal retaining rings 16 are inserted.The annular housing 3, the annular piston 11 received therein and the release housing 12 extend annularly about a central axis Z. When hydraulic fluid flows into the pressure chamber 12 bvia the inlet opening 12 a, the annular piston 11 moves to the left in the illustration shown in the axial direction with respect to the central axis Z, which corresponds to a stroke movement, and closes the clutch 2. as soon as the clutch 2 is closed, a full torque of an engine (not shown in the figures) can be transmitted. When the hydraulic pressure in the pressure chamber 12b is relieved again, the ring piston 11 moves back into its starting position (to the right in the illustration) and the clutch 2 is opened. In this position, no torque transmission is possible. The clutch 2 presses the ring piston 11 back into the starting position.With reference now to FIG. 2, an embodiment of a clutch device 1 according to the invention is described, wherein analogous components and functions are no longer discussed separately in detail.The clutch device 1 according to the invention also comprises the clutch 2, the annular housing 3 and the disengagement device 10 with the annular piston 11 accommodated therein. while the annular housing 3 can be produced, in particular cast, from a metal, for example aluminum or steel, the disengagement housing 12 of the disengagement device 10 can be produced from a polymer. Similarly to the prior art, O-rings 4 are inserted between the releaser housing 12 and the annular housing 3 for sealing against the wet chamber 5.Unlike in the prior art, in the clutch device 1 according to the invention, the pressure chamber 12 bis arranged exclusively laterally of the annular piston 11. The ring piston 11 has an inner side surface 11 aand an outer side surface 11 b, wherein a first groove sealing ring 13 and a second groove sealing ring 14 engage on the radially outer side surface 11 band together with the outer side surface 11 band a radial outer surface 12 dof the release housing 12 form the pressure chamber 12 b. As can be seen, the inlet opening 12 ato the pressure chamber 12 bis designed here as a short pipe socket which projects into the pressure chamber 12 band is positioned in the axial direction between the first groove sealing ring 13 and the second groove sealing ring 14.The release case 12 is made considerably smaller than that of the prior art, covering the ring piston 11 number on its radially outer side surface 11b. The release housing 12 thus forms an open housing without a base. This results in a cost-effective and material-saving coupling device 1 that requires at the same time little installation space.With reference to Figures 3a and 3b, which show a cross-sectional view of the clutch device 1 according to the invention in the engaged state (Figure 3a) and in the disengaged state (Figure 3b), the clutch device 1 and the function will be explained in more detail.The annular housing 3 comprises a radially outer side wall 3 c, a bottom wall 3 dand a radially inner side wall 3 e. In this case, an outer pressure chamber 3 ais formed between the release housing 12 and the radially outer side wall 3 cof the annular housing 3, into which chamber an inlet 3 bopens, which inlet extends here as a radial bore through the outer side wall 3 cof the annular housing 3. As can be seen in FIG. 3 a, the annular piston 11 bears with an axial end region 11 gin an initial state directly against the annular housing 3, namely against a bottom wall 3 dthereof.As can be seen in the sectional views of FIGS. 3 aand 3 b, the inlet 3 bis only slightly offset in the axial direction with respect to the inlet opening 12 aof the release housing 12, wherein they are arranged here at an equal angle in the circumferential direction, such that the inlet opening 12 aand the inlet 3 bare partially positioned with respect to one another.The annular piston 11 has at least a first region 11 chaving a first outer diameter D and a second region 11 dhaving a second outer diameter d, wherein the first outer diameter D is greater than the second outer diameter d. The first region 11 cchanges over into the second region 11 don an outer shoulder 11 e.The illustration of FIG. 3 bdiffers from that of FIG. 3 ain that the disengagement device 10 is illustrated in FIG. 3 bin the disengaged state, in which the ring piston 11 is displaced to the left in the direction of the hollow arrow compared to the illustration of FIG. 3 a, and thus actuates the clutch 2 via the disengagement bearing 15. The release housing 12 also abuts with an axial end 12e against the bottom wall 3d of the annular housing 3, but the axial end portion 11g of the ring piston 11 is now spaced from the bottom wall 3d.Referring now to Figures 4a and 4b, the release device 10 of the present invention will be described in more detail. As can be seen, the first and second groove sealing rings 13; 14 are arranged in the second region 11d of the annular piston 11. The outer shoulder 11 etherefore serves as a seat of the second groove sealing ring 14, which rests with a static sealing lip 14 aon the ring piston 11 and with a dynamic sealing lip 14 bon the release housing 12. As can be seen, the inlet opening 12 aof the release housing 12 which is designed as a tubular connection forms an abutment wall for the first groove sealing ring 13, which is a static seal. The inner side surface 11a of the annular piston 11 forms a radially inner shoulder 11f from which it serves to form a bearing for the release bearing 15.In FIG. 4 a, the disengagement device 10 is shown in the initial position, while in FIG. 4 b it is shown in the disengaged state, wherein the ring piston 11 is offset by the stroke H. As can be seen in comparison with the two figures, the first groove sealing ring 13 remains in place during a movement of the annular piston 11, while the second groove sealing ring 14 is carried along with the annular piston 11 during its disengagement movement.In summary, it should be noted that in the embodiments according to the invention, the release housing 12 is "halved" and thus "opened" compared to the prior art. The annular piston 11 is adapted according to the available installation space and can be manufactured in a simple geometric form. Since the first groove sealing ring 13 is formed as a stationary seal, only one dynamic / moving seal exists, namely the second groove sealing ring 14. An installation space required for the disengagement device is reduced compared to the prior art, as a result of which further costs are saved. Since no dynamic seal is required on the radially inner side surface 11 aof the annular piston 11, no problems arise with a rotation of such an inner seal, as is frequently the case in the prior art.List of reference characters1 Clutch device 2 Clutch 3 Housing 3 a Äußerer pressure chamber 3 b Zulauf 3 c Äußere side wall 3 d Bodenwand wall 3 e Innere side wall 4 O-ring 5 Wet chamber 10 Disengagement device 11 Ring piston 11 a Innere side surface 11 b Äußere side surface 11 cFirst region 11 dSecond region 11 e Äußere shoulder 11 f Innere shoulder 11 gAxial end region 12 Disengagement housing 12 a Einlassöffnung opening 12 bPress chamber 12 c Aufnahme 12 dRadial outer side 12 eAxial end 13First groove sealing ring 14Second groove sealing ring 14 aStatic sealing lip 14 bDynamic sealing lip 15 Disengagement bearing 16 Sheet metal retaining ring Z Center axis D Outer diameter of first region d Outer diameter of second region

Claims

Disengagement device (10) for a clutch device (100) of a motor vehicle (1), comprising: an annular piston (11) which is accommodated in an annular disengagement housing (12) such that it can slide in the axial direction with respect to a central axis Z of the disengagement housing (12) upon application of a hydraulic pressure, wherein the annular piston (11) has a radially inner side face (11a) and a radially outer side face (11b), wherein the radially outer side face (11b) adjoins the annular disengagement housing (12) and is sealed against the annular disengagement housing (12) by means of a first groove sealing ring (13) and a second groove sealing ring (14), wherein an inlet opening (12a) for the passage of hydraulic fluid is present in the disengagement housing (12), wherein the inlet opening (12a) is positioned between the first groove sealing ring (13) and the second groove sealing ring (14), characterized in that the first groove sealing ring (13) and the second groove sealing ring (14) engage on the radially outer side surface (11b) of the annular piston (11) and together with the outer side surface (11b) and with the release housing (12) delimit a pressure chamber (12b) for the hydraulic fluid.Disengagement device (10) according to Claim 1, characterized in that the annular piston (11) has at least one first region (11c) with a first outer diameter D and a second region (11d) with a second outer diameter d, the first outer diameter D being greater than the second outer diameter d, the first region (11c) merging into the second region (11d) via an outer shoulder (11e), and the first and the second groove sealing rings (13; 14) being arranged in the second region (11d).Disengagement device (10) according to Claim 1 or 2, characterized in that the disengagement housing (12) delimits the annular piston (11) exclusively on its outer side face (11b).Disengagement device (10) according to one of the preceding claims, characterized in that the inlet opening (12a) is designed as a pipe socket, wherein a receptacle (12c) for the first groove sealing ring (13) is delimited in an axial direction by the pipe socket.Disengagement device (10) according to Claim 4, characterized in that the annular piston (11) is movable in the axial direction relative to the first groove sealing ring (13) during a stroke movement.Disengagement device (10) according to one of the preceding claims, characterized in that the second groove sealing ring (14) has a static sealing lip (14a) and a dynamic sealing lip (14b), wherein the static sealing lip (14a) bears against the radially outer side face (11b) and the dynamic sealing lip (14b) bears against the disengagement housing (12).Disengagement device (10) according to one of the preceding claims, characterized in that a radially inner shoulder (11f) is formed on the radially inner side face (11a) of the annular piston (11), said shoulder serving as a bearing face for a disengagement bearing (15).Clutch device (1) comprising a clutch (2) and a disengagement device (10) according to one of the preceding claims, wherein the clutch (2) is operatively connected to the disengagement device (10) via a disengagement bearing (15), wherein the clutch device (1) comprises an annular housing (3) which at least partially surrounds the disengagement housing (12) and is arranged concentrically with respect thereto, wherein the annular housing (3) forms an outer pressure space (3a) with a radial outer side (12d) of the disengagement housing (12).Clutch device (1) according to Claim 8, characterized in that the housing (3) has formed in it an inlet (3b) through an outer side wall (3c) of the housing (3) to the outer pressure space (3a), which in the circumferential direction, with respect to the centre axis Z, encloses an angle of between 0° and 30° with the inlet opening (12a) of the release housing (12).Clutch device (1) according to Claim 8, characterized in that the housing (3) has the outer side wall (3c), a bottom wall (3d) and an inner side wall (3e), wherein the outer side wall (3c) is connected to the inner side wall (3e) via the bottom wall (3d) and wherein the bottom wall (3d) adjoins an axial end (12e) of the release housing (12) and bears against the latter.

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