Clutch with double-acting piston and axially elastic end stop discs for a sliding sleeve

Abstract

The present invention relates to a clutch (1) for coupling and decoupling an engine to and from the drivetrain of a motor vehicle, the clutch comprising a piston (2) positioned in a housing (3) so as to be axially displaceable between two pressure chambers (6, 7) as a result of pressure, the piston (2) being connected to an actuating bell (8) configured to contact / move a sliding sleeve (9), and provided with axially elastic end stop discs (22) for limiting the axial displaceability of the sliding sleeve (9).

Description

[Technical Field]

[0001] The present invention relates to a clutch for coupling and decoupling a motor to and from a motor vehicle drivetrain, the clutch comprising a piston arranged in a housing and having, for example, a pressure connection between two pressure chambers, each of the two pressure chambers being connected to one of the pressure connections so as to be axially displaceable by pressure, the piston being connected, for example, in a material-bonded, form-fitting, and / or pressure-fitting or integral manner, to a separate or integrated actuation cap which is arranged to contact / displace a sliding sleeve. [Background technology]

[0002] Decoupling devices for decoupling a motor from a drive train are already known from the prior art, for example DE 10 2021 101 141 A1 discloses such a decoupling device, which may also be referred to as a clutch.

[0003] This older prior art relates to a decoupling device for decoupling a motor from a drivetrain, the decoupling device having a piston displaceably mounted within a housing parallel to a longitudinal axis L of the housing and having an arm for indirectly or directly actuating a clutch element, a first region of the piston operatively connected to a first pressure space such that application of pressure to the first pressure space causes the piston to displace in a first direction parallel to the longitudinal axis L, and a second pressure space is provided, the second pressure space operatively connected to a second region of the piston such that application of pressure to the second pressure space causes the piston to displace in a second direction parallel to the longitudinal axis L, the second direction being opposite to the first direction. The present invention also relates to such objects which are considered to be included herein. In this prior patent application, it is particularly emphasized that the first region is located at a first longitudinal end of the piston and the second region is formed by a recess in the outer surface of the piston, and that the recess is formed in the outer half of the outer surface of the piston, viewed radially relative to the longitudinal axis L. It has also been found to be advantageous for each of the pressure spaces to have one pressure connection each. In addition, the piston should be configured as an annular piston extending around the longitudinal axis L.

[0004] Furthermore, the prior patent application, which should be considered incorporated herein with respect to its functional and operational context and geometrical configuration, includes a first ball bearing located radially inward of the piston, on which the piston arm is mounted, whereby the first ball bearing is mounted radially inward and has a meshing portion configured to actuate a clutch element at its free end. A second ball bearing may be included, on which the housing is supported radially outward.

[0005] Similar devices are known from DE 102014213884 A1 and JP 04-203626 A1.

[0006] The clutches known from the prior art, in particular the clutches identified above, have drawbacks that must be improved or at least alleviated, in particular the aim being to achieve a better functioning and, above all, adjustable solution. Summary of the Invention [Problem to be solved by the invention]

[0007] This object is achieved in the general clutch according to the invention in that end stop discs configured to be axially elastic are provided to limit the axial displacement potential of the sliding sleeve / shift sleeve. [Means for solving the problem]

[0008] Due to hydraulic actuation, the end stops of the shift piston are easily controlled. As a result, unacceptable NVH noise does not occur between the sliding sleeve and the clutch body. In this solution, an S-disc is used as the end stop between the locking ring and the clutch body. The S-disc can be configured to be elastic specifically for the application, thereby reducing noise at the end stops. The S-disc can be mounted between the clutch body and the locking ring with an appropriate preload force. An improved disconnect unit with hydraulic actuation is now possible, particularly for electric front axles and dual-drive E-axles. While multiple-disc clutch concepts are known on the market, they are currently being improved. Until now, the discs were always preloaded when the shift piston was under force, and the end stops of the multiple-disc clutch were the discs themselves. However, improved variations are now possible. Due to current requirements, instead of a multiple-disc clutch, a dog clutch is engaged with a form fit. However, shift noise at the end stops is avoided. Due to hydraulic actuation, the end stops of the shift piston are still not easy to control, but unacceptable noise is avoided. Hard end stops between the clutch body and the sliding sleeve are avoided. Currently known end stops that rely on a form fit, for example, by using a "hump" on the clutch body, or on a form fit, for example, by three end stops on the sliding sleeve itself, are not necessary here. In the solution according to the invention, an S-disc is used as the end stop between the locking ring and the clutch body. The S-disc can be configured elastically, depending on the application, which reduces noise at the end stop. The S-disc can be installed with an appropriate preload force between the clutch body and the locking ring.

[0009] The present invention also provides a system that functions for double-acting pistons operating in an alternating fashion. This new concept focuses on developing two variable pressure spaces within a single housing using a baffle plate and a variable pressure connection using a pressure space sleeve. To return to a disengaged state when the dog clutch is engaged, the baffle plate is placed behind a second seal, changing the configuration of the pressure spaces. In a first variant, a housing configuration is provided that confines a piston that can operate in two directions. The piston is inserted into the housing with two seals, similar to a standard hydraulic clutch slave cylinder. Here, the first pressure chamber and pressure connection are located next to the ring piston, e.g., to the right of the ring piston, providing the forward stroke. In this case, the second pressure chamber is located, e.g., to the left of the tapered section of the ring piston. This second pressure chamber is made possible by inserting a baffle plate into the housing with a third seal and securing it with a circlip. This has a second pressure connection that moves the piston back to the left when pressure is applied, thereby providing the return stroke. However, in some embodiments, the piston must logically consist of two parts for assembly.

[0010] A variant that avoids this is characterized by the fact that the second pressure chamber is relocated inward, beneath the piston. In this case, a pressure space sleeve is used to accommodate the pressure connection within the limited installation space inside the housing. It is equipped with an annular groove and two outer O-rings and is fixed to the housing with a circlip. In this regard, two holes in the annular groove ensure the flow of the working medium.

[0011] It should be noted that in general the piston should always be guided and centered via the sliding belt. The baffle plate is sealed to the housing using an O-ring. End stops are implemented via additional webs on the baffle plate when the mating parts are disengaged. In both variants, a sensor path measurement is provided. An X-seal ring can be used when pressure is applied from both sides (pressure chambers 1 and 2) (alternating manner).

[0012] The present invention is particularly well suited to hydraulic actuation of the front E-axle and clutch / decoupling units, particularly when using dog clutches.

[0013] Finally, the present invention provides a hydraulically actuated DCU / disconnect unit for an E-axle with a locking element. This invention achieves significant improvements. Unwanted residual pressure in the shift piston (connection P1 or P2) from the hydraulic system, due to the form-fit connection between the shift piston and the sliding sleeve, can cause abnormal movement of the shift piston within the pressure chambers P1 and P2, in addition to movement of the sliding sleeve. Such unintended movement can have significant consequences for both functionality and functional safety (e.g., tooth breakage, uncontrollable vehicle operation). Hydraulic systems can be implemented with additional effort, or pressure valves can be implemented in a complex manner using additional valves. This is no longer necessary. At the same time, due to the complex hydraulic valves, the controllability and positioning of the shift piston were not robust in the past. This also achieves improvements. The use of a locking element within / with a moving part leads to an improved DCU. The locking element between the shift cylinder and the shift piston can be a single locking element, such as a slotted wire ring, a molded wire ring, or a pressure piece with a spiral spring. At the same time, it is also useful to use a locking element between the sliding sleeve and the idler gear. The role of both locking elements is to prevent abnormal axial movement of the shift piston, which is successful. The axial force is distributed between both locking elements, ensuring the end positions of the sliding sleeve and the shift piston simultaneously. To minimize friction, axial play is ensured between the sliding sleeve and the shift piston.

[0014] Here, an improved disconnection unit with hydraulic actuation is introduced, especially for the front axle and dual drive E-axle. Due to current knowledge and a new concept that utilizes form-fitting (not frictional engagement), this type of solution is still unknown.

[0015] This invention relates to a DCU / disconnect unit for an E-axle with a dual-function shift crown. The concept of a multi-disc clutch is known on the market. Until now, the discs were always preloaded by the shift piston under force. The soft end stops of a multi-disc clutch were the discs themselves. Due to current requirements, a torque clutch is engaged with a form fit instead of a multi-disc clutch. This results in shift noise during engagement, which can now be avoided. Due to hydraulic actuation, the teeth and tooth position of the shift piston / shift crown cannot be easily controlled with the appropriate speed and force. This still applies, but previously unacceptable NVH noise is avoided. In other cases, such noise is usually generated between the sliding sleeve / shift sleeve and the clutch body. Currently known solutions are based on synchronization and the use of a shift fork with a corresponding stiffness. However, in this case, the assembly of the shift crown / shift piston with the sliding sleeve must also be considered. This is completely avoided here, and the axial stiffness is preset, simplifying assembly. Hard end stops at the engagement point between the clutch body and the sliding sleeve are reduced. A robust assembly is achieved with the help of a snap connection to the sliding sleeve. This solution utilizes a special configuration of the shift crown, which simultaneously takes into account assembly and axial stiffness. The shift crown has a special arm configuration for assembly and stiffness. Using a lever for radial stiffness, it is possible to implement a snap connection to the web of the sliding sleeve in the groove of the shift crown / shift piston. The lever for axial stiffness also allows for good adjustment of the axial stiffness.

[0016] Advantageous embodiments are claimed in the dependent claims and are explained in more detail below.

[0017] Thus, it is advantageous if the end stop discs have an S-shape or double S-shape in longitudinal cross section along the axis of rotation of the clutch.

[0018] It is also advantageous if the end stop discs are mounted in a preloaded manner.

[0019] It is further advantageous if the end stop discs are mounted on a shaft, for example an intermediate shaft.

[0020] An advantageous embodiment is also characterized in that the end stop disc is mounted with a preload force between the clutch body, which is prepared for torque connection with the sliding sleeve, and a locking ring fixed to the shaft.

[0021] It has proven advantageous if the radial extension of the end stop disc is greater than the radial extension of the clutch body.

[0022] It is also advantageous if a space is enclosed between the end stop disc and the clutch body.

[0023] It is further advantageous if the locking ring is arranged in an axially position-fixed manner in a groove provided on the outer surface of the shaft.

[0024] An advantageous embodiment is further characterized in that the end stop disc is configured to be at least 10 times (up to 100 times) more elastic in the axial direction than the locking ring and / or the clutch body.

[0025] Furthermore, it may be advantageous if a stop disk / baffle plate is arranged in the pressure chamber, in particular separately from the housing and the piston, which stop disk / baffle plate limits the axial displacement possibility of the piston at least in the axial direction. In this way, a variable pressure space / pressure chamber and pressure connection for a piston acting in an alternating manner is implemented. The present invention further focuses on two variants for implementing a variable pressure chamber for a piston acting in an alternating manner.

[0026] It is advantageous if the stop disk is arranged radially inside or radially outside the piston. A radially inside arrangement has the advantage, in particular, that the piston can be formed integrally with the actuation cap. A radially outside arrangement may achieve better utilization of the installation space, in particular less installation space. However, this may have drawbacks during assembly.

[0027] If the piston is arranged for double acting / alternating pressure, actuation in one axial direction and in the opposite axial direction is possible in a small installation space.

[0028] It has also proven advantageous if the stop disc has at least one axial protrusion that abuts against the axial piston and is configured to penetrate one of the pressure chambers, resulting in a targeted configuration and use of installation space.

[0029] If the stop disc has a plurality of axial protrusions distributed around the circumference protruding from one end face, it is possible to effectively prevent the piston / ring piston from getting stuck in the housing. In particular, an evenly distributed arrangement of the axial protrusions is particularly advantageous in this regard.

[0030] An advantageous embodiment is also characterized in that a circlip fixed in the housing determines at least the axial position of the stopping disc, for example together with a step in the housing.

[0031] It is advantageous if the sliding sleeve is connected to the actuation cap. This can also simplify assembly. This connection can be permanent or temporary.

[0032] It is also advantageous if at least one mechanical locking element is formed and arranged between the axially movable component and the axially fixed component in such a way that it can lock or unlock the sliding sleeve in two different axial positions depending on the operating state.

[0033] It is therefore advantageous if the locking element is arranged on the one hand on an (axially) movable component, i.e. the shift sleeve or the piston, and on the other hand on an axially fixed component, i.e. the idler gear or the housing.

[0034] The locking element is advantageously arranged in a spring-loaded manner in a seat of the axially fixed (or axially movable) component for selectively engaging in a locking manner between two grooves of the axially movable (or axially fixed) component.

[0035] In this regard, it has been found to be advantageous for the groove to form a recess that is inclined on both sides.

[0036] It is advantageous if the locking / stopping action is forced when the locking element engages in one of the two grooves.

[0037] For particularly good distribution of forces, it has been found to be advantageous to utilize multiple locking elements.

[0038] It is desirable that at least one of the locking elements / the locking elements is formed as a ball or is spherical.

[0039] An advantageous embodiment is also characterized in that two detents, each with a locking element, are provided at the same radial distance from the axis of rotation of the clutch.

[0040] In this respect it is advantageous if the grooves are provided in the hardened insert.

[0041] The actuation cap is preferably configured as a cantilever and has a portion with a snap-fit ​​at one free end for engaging with the sliding sleeve.

[0042] It is also advantageous if the cantilever protruding from the base of the actuation cap is spaced apart via a slot / recess extending between the cantilever and the base, whereby the axial and radial resilience / stiffness are adjusted in a targeted manner. Thus, the cantilever is (mostly, but not completely) separated from the base via the slot. The resilience / stiffness in both the axial and radial directions is adjusted in a targeted manner via the extension.

[0043] It has been found to be advantageous for the slots to only partially penetrate the material of the actuation cap in the circumferential direction, but completely penetrate radially.

[0044] It is also useful if the cantilever is provided with an elongated hole. A particularly precise adjustment of the stiffness / elasticity can then be made.

[0045] Manufacturing is simplified if the elongated holes run parallel to the slots and preferably have the same axial width.

[0046] It is advantageous if a cantilever defines the lever, as this simplifies pre-adjustment.

[0047] Assembly is simplified if the snap-fastening surrounds the radial projection of the sliding sleeve with axial play.

[0048] It is advantageous if the slots are configured as rectangular through-holes.

[0049] An advantageous embodiment is also characterized in that the cantilever is configured in an L-shape or a Z-shape.

[0050] The invention is explained in more detail below with the aid of the drawings. [Brief explanation of the drawings]

[0051] [Figure 1] 1 shows a partially illustrated longitudinal section of a clutch according to the invention, in which two pressure spaces are provided radially outside the piston. [Figure 2] 2 shows the operating position of the clutch of FIG. 1 for "meshing engagement." [Figure 3] 3 shows the clutch of FIGS. 1 and 2 in a "disengaged" operating position; [Figure 4] 1 shows a clutch according to the present invention, where a pressure chamber is provided radially inward of the piston. [Figure 5] The operating positions of the clutch of FIG. 4 are shown in an "engaged" operating position (FIG. 5) and a "disengaged" operating position (FIG. 6). [Figure 6] The operating positions of the clutch of FIG. 4 are shown in an "engaged" operating position (FIG. 5) and a "disengaged" operating position (FIG. 6). [Figure 7] 3 shows a detail of a longitudinal section of a further clutch according to the invention in a first operating position, in which an intermediate shaft fitted with end stop discs is used as a special feature. [Figure 8] 8 shows a part of a longitudinal section of a further clutch according to the invention, with the shift sleeve and the actuation cap in a second operating position, which is an axially displaced position relative to FIG. 7; [Figure 9] Detail of the shifted position of the actuation cap is shown, with the snap fastening shown enlarged in longitudinal section in FIG. 9 and the cantilever shown enlarged in perspective view in FIG. 10. [Figure 10]Detail of the shifted position of the actuation cap is shown, with the snap fastening shown enlarged in longitudinal section in FIG. 9 and the cantilever shown enlarged in perspective view in FIG. 10. DETAILED DESCRIPTION OF THE INVENTION

[0052] These figures are merely schematic in nature and serve only to understand the invention. Identical elements are provided with identical reference symbols. Features of the individual embodiments can be interchanged.

[0053] FIG. 1 shows a clutch 1. The clutch 1 has a piston 2. The piston 2 is configured for double-acting / alternating pressure application. The piston 2 is arranged in a housing 3. Pressure connections 4 and 5 lead to a first pressure chamber 6 and a second pressure chamber 7, respectively. In this respect, reference is also made to FIGS. 2 and 3. The pressure connection 4 leads to the first pressure chamber 6. The pressure connection 5 leads to the second pressure chamber 7. Naturally, this solution can also be implemented in reverse.

[0054] An actuation cap 8 is also attached to the piston 2. In the clutch 1 of Figures 1-3, the piston 2 and actuation cap 8 are two separate components that are attached to one another. In the clutch 1 of Figures 4-6, the piston 2 and actuation cap 8 form an integrated, single-material, seamless component.

[0055] The actuating cap 8 engages with a sliding sleeve 9. The clutch 1 of Figures 1 to 6 is also provided with a stop disc / baffle plate 10. The stop disc 10 has a first seat 11 on the radially outer side and a second seat 12 on the radially inner side.

[0056] As can be seen in Figures 2 and 3, a seal 13 is provided on each of the two seats 11 and 12. These seals 13 seal the pressure chamber 7, i.e. the second pressure chamber. Two further seals 14 seal the first pressure chamber 6. The stop disc 10 has an axial protrusion 15. In the "disengaged" operating position, the axial protrusion 15 protrudes completely through the second pressure chamber 7 and abuts the piston 2, as shown in Figure 3. Here, the axial protrusion 15 protrudes from an end face 16 of the piston 2.

[0057] There is a circlip 17 and a step 18 to which the stopping disc 10 is indirectly or directly fixed about its axial position. This can be seen particularly well in figures 5 and 6.

[0058] 4, attention should be paid to the pressure space sleeve 19. This pressure space sleeve 19 is necessary to connect the pressure connection 5 to the second pressure chamber 7.

[0059] In this regard, the pressure space sleeve 19 is fixed in place via a pressure space sleeve circlip 20 by the insertion of a seal in the form of an O-ring 21 .

[0060] Figure 7 shows a clutch 1 with an end stop disc 22, which is axially arranged between a locking ring 23 and a clutch body 24. These last two components are located on the outer surface 25 of an (intermediate) shaft 26. There is also an idler gear 27.

[0061] The end stop disc 22 has an S-shape and is axially resilient. The end stop disc 22 is made of sheet metal. A space 28 is defined between the end stop disc 22 and the clutch body 24. The locking ring 23 is seated in a groove 29 in the outer surface 25.

[0062] A number of locking elements are provided, namely locking elements 30 and 31. Both locking elements 30 and 31 are configured as balls. Locking element 30 seats in a locking element receiving groove / groove 32 in housing 3, while locking element 31 seats in a locking element receiving groove / groove 33. Locking element 30 is intended to lock its insertion in groove 34, while locking element 31 is intended to engage in an identical groove 35 in an insert 36 fixed in piston 2. These grooves 34 and 35 have inclined surfaces. The rotation axis is designated by the reference number 37.

[0063] A bearing 38 is also provided on the (intermediate) shaft 26 .

[0064] In FIG. 7 one position of the clutch is assumed, whereas in FIG. 8 the other shift position of the clutch 1 is assumed.

[0065] In this respect, attention should again be paid to the configuration of the actuation cap 8 with a base 38, which transitions into a cantilever 39, which forms at its free end a snap-fit ​​40 which, with axial play, surrounds a radial projection 41 of the sliding / shifting sleeve. In this respect, reference should also be made to FIG. 9.

[0066] 10, the end of the snap-like cantilever 39 is configured in the manner of a clip or gripper, on the one hand it is provided with a slot 42 and on the other hand it is provided with an elongated hole 43 for targeted adjustment of the elasticity / stiffness indicated by portions 44 and 45.

[0067] 1, in Fig. 10 the axial direction is indicated by reference numeral 46 and the radial direction is indicated by reference numeral 47. In Fig. 10, the circumferential direction is indicated by reference numeral 48.

[0068] As a result, the cantilever 39 forms a lever 49 . [Explanation of symbols]

[0069] 1 clutch 2 pistons / shift pistons 3 Housing / (shift) cylinder 4 Pressure Connections 5 Pressure Connection 6. First Pressure Chamber 7 Second Pressure Chamber 8 Operating Cap 9 Slide sleeve / shift sleeve 10 Stop disc / baffle plate 11 First Sheet 12 Second Sheet 13 Seal 14 Seals 15 Axial protrusion 16 End face 17 Circlip 18 steps 19 Pressure space sleeve 20 Pressure Space Sleeve Circlip 21 O-ring 22 End Stop Disc 23 Locking Ring 24 Clutch body 25 External surface 26 (intermediate) shaft 27 Idler gear 28 Space 29 Groove 30 Locking Elements 31 Locking Elements 32 Locking element receiving groove / groove 33 Locking element receiving groove / groove 34 channels / grooves 35 channels / grooves 36 Insertion section 37 Rotation axis 38 Base 39 Cantilever 40 snap closure 41 Radial protrusion 42 slots / recesses 43 Slot 44 Elasticity / Rigidity 45 Elasticity / Rigidity 46 Axial 47 Radial 48 Circumferential direction 49 Lever

Claims

1. A clutch (1) for coupling and decoupling a motor to and from a drive train of a motor vehicle, comprising a piston (2) arranged in a housing (3) between two pressure chambers (6, 7) so as to be axially displaceable by pressure, said piston (2) being connected to an actuation cap (8) arranged to contact / displace a sliding sleeve (9), an end stop disk (22) configured to be axially elastic being provided to limit the axial displaceability of said sliding sleeve (9), A clutch (1), characterized in that the end stop discs (22) have an S-shape in longitudinal section along the axis of rotation (37) of the clutch (1).

2. A clutch (1) for coupling and decoupling a motor to and from a drive train of a motor vehicle, comprising a piston (2) arranged between two pressure chambers (6, 7) in a housing (3) so as to be axially displaceable by pressure, said piston (2) being connected to an actuation cap (8) which is arranged to contact / move a sliding sleeve (9), and an end stop disc (22) which is arranged to be axially elastic is provided to limit the axial displaceability of said sliding sleeve (9), A clutch (1) characterized in that said end stop discs (22) are mounted in a preloaded manner.

3. A clutch (1) according to claim 1 or 2, characterized in that the end stop discs (22) are mounted on a shaft (26).

4. A clutch (1) for coupling and decoupling a motor to and from a drive train of a motor vehicle, comprising a piston (2) arranged between two pressure chambers (6, 7) in a housing (3) so as to be axially displaceable by pressure, said piston (2) being connected to an actuating cap (8) which is arranged to contact / move a sliding sleeve (9), and an end stop disc (22) which is arranged to be axially elastic is provided to limit the axial displaceability of said sliding sleeve (9), A clutch (1), characterized in that the end stop disc (22) is mounted with a preload force between a clutch body (24) prepared for torque connection with the sliding sleeve (9) and a locking ring (23) fixed to a shaft (26).

5. 5. A clutch (1) according to claim 4, characterized in that the radial portion of said end stop discs (22) is greater than the radial portion of said clutch body (24).

6. 5. A clutch (1) according to claim 4, characterized in that a space (28) is enclosed between said end stop disc (22) and said clutch body (24).

7. 5. A clutch (1) according to claim 4, characterized in that the locking ring (23) is arranged in an axially fixed manner in a groove (29) on the outer surface (25) of the shaft (26).

8. 5. A clutch (1) according to claim 1, 2 or 4, characterized in that the sliding sleeve (9) is connected to the actuation cap (8).

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