Clutch with a piston pressurizable on both sides and a snap-fastening part with a cantilever arm

Abstract

The present invention relates to a clutch (1) for coupling and decoupling a motor to and from a drivetrain of a motor vehicle, comprising a piston (2) arranged in a housing (3) between two pressure chambers (6, 7) in an axially movable manner depending on pressure, the piston (2) being connected to an actuation cap (8) configured to contact / move a shift sleeve (9), the actuation cap (8) having a portion configured as a cantilevered arm (39) and having a snap-fastening portion (40) at its free end for engaging with the shift sleeve (9).

Description

[Technical Field]

[0001] The present invention relates to a clutch for connecting and disconnecting a motor to and from a motor vehicle drivetrain, which has a piston arranged in a housing having pressure connections, for example, between two pressure chambers each connected to one of the pressure connections, so that it can be axially displaced by pressure, and which piston is connected in a material-bonded, form-fit and / or pressure-fit or integral manner to a separate or integral actuating cap, for example, which is arranged to contact / displace a sliding sleeve. [Background technology]

[0002] Decoupling devices for decoupling the motor from the drive train are already known from the prior art, for example in DE 102021101141 A1, which 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 movably mounted within a housing parallel to a longitudinal axis L of the housing and having an arm for directly or indirectly actuating a coupling 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 move 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 move in a second direction parallel to the longitudinal axis L, the second direction being opposite the first direction. The present invention also relates to such an object, which will be 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. Furthermore, it has been found to be advantageous for each of the pressure spaces to be provided with a pressure connection. In addition, the piston should be formed as an annular piston extending around the longitudinal axis L.

[0004] Furthermore, the prior patent application, which is considered to be included when disclosed herein in terms of functional and operative relationship and geometric 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 also 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 should be eliminated 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 according to the invention in that the actuating cap has a portion configured as a cantilever arm and has at its free end a snap-fastening portion for engaging with the sliding sleeve. [Means for solving the problem]

[0008] This invention relates to a DCU / disconnect unit for an electric axle with a dual-function shift crown. The concept of multiple disc clutches is well known in the market. Until now, discs were constantly preloaded using a shift piston. In multiple disc clutches, the soft end stops were the discs themselves. Due to current requirements, multiple disc clutches are being replaced by form-fit torque clutches. Torque clutches cause shift noise during engagement (engagement), which is now avoided. Due to hydraulic actuation, the engagement position of the shift piston / shift crown cannot be easily controlled with the appropriate speed and force. While this still applies, previously unacceptable NVH disturbances are avoided. These would otherwise occur between the sliding sleeve / shift sleeve and the clutch body. Previous solutions involved shift forks with synchronization and corresponding stiffness. Additionally, the shift crown / shift piston had to be assembled with the sliding sleeve. This is all avoided here, providing axial stiffness. This simplifies assembly. Hard end stops at the engagement position between the clutch body and sliding sleeve are reduced. A robust assembly is achieved with the help of a snap connection to the sliding sleeve. This solution uses 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 mounting and stiffness. Using a lever for radial stiffness, it is possible to realize a snap connection between the groove of the shift crown / shift piston and the web of the sliding sleeve. The lever for axial stiffness also makes it easy to adjust the axial stiffness. With regard to function, it is particularly advantageous to take the axial stiffness into account by selecting the appropriate material thickness and respective length. The shape and configuration must also remain in focus.

[0009] The present invention also discloses a system that functions for bidirectionally actuating / interacting pistons. The new concept focuses on developing two variable pressure chambers using baffle plates and a variable pressure connection using a pressure space sleeve for implementation within a single housing. To return the dog clutch to its open state when the dog clutch is closed, a baffle plate is placed behind a second seal, changing the configuration of the pressure chambers. In the first variant, a housing configuration incorporating a piston that can be actuated in two directions is shown. The piston is inserted into a housing with two seals, similar to a standard hydraulic clutch slave cylinder. The first pressure chamber and pressure connection are located adjacent to the right side of the annular piston, for example, to provide the prestroke. The second pressure chamber is then located to the left of the tapered section of the annular piston, for example. This second pressure chamber is made possible by inserting a baffle plate with a third seal into the housing and securing it with a circlip. This has a second pressure connection that returns the piston to the left when pressure is applied, thereby creating the return stroke. However, in some configurations, the piston must be made in two pieces for assembly.

[0010] A variant that avoids this is characterized by the second pressure chamber being moved inward, towards the underside of the piston. To accommodate the pressure connection in the limited space inside the housing, a pressure space sleeve is used. It has an annular groove and two O-rings on the sides and is fixed to the housing with a circlip. Two holes in the annular groove ensure the flow of the working medium.

[0011] It should be understood that in general the piston should always be guided and centered via the sliding band. The baffle plate is sealed to the housing with an O-ring. The end stops when the engagement is open are realized via additional webs on the baffle plate. In both variants, sensor displacement measurement is provided. Since it is pressurized (alternately) from both sides (pressure chambers 1 and 2), an X-seal ring can be used.

[0012] The present invention is particularly suitable for hydraulic actuation of the front E-axle and coupling / decoupling units, particularly when using dog clutches.

[0013] Advantageous embodiments are claimed in the dependent claims and are explained in detail below.

[0014] It is therefore advantageous if the cantilevered arms projecting from the base of the actuation cap are spaced apart by a slit / recess extending between the cantilevered arms and the base, thereby allowing the elasticity / stiffness in the axial and radial directions to be selectively adjusted. The cantilevered arms are therefore (mostly, but not completely) spaced apart from the base via the slit. The extension allows the elasticity / stiffness to be selectively adjusted in both the axial and radial directions.

[0015] It has been found to be effective if the slits extend only partially through the material of the actuation cap in the circumferential direction, but completely through the material in the radial direction.

[0016] It is also advantageous if the cantilevered arm has a slot. A particularly precise adjustment of the stiffness / elasticity can then be made.

[0017] Manufacturing is simplified if the slots run parallel to the slits and preferably have the same axial width.

[0018] It is advantageous if the cantilevered arm defines the lever. Presetting is then easier.

[0019] Assembly is made easier if the snap fastening with axial clearance surrounds the radial projection of the sliding sleeve.

[0020] It is useful if the slot is configured as a rectangular through opening.

[0021] An advantageous embodiment is also characterized in that the cantilevered arms are configured in an L-shape or a Z-shape.

[0022] It is advantageous if a stop disk / baffle plate is arranged in the pressure chamber, in particular away from the housing and the piston, and limits the axial movement of the piston in at least one axial direction. In this way, a variable pressure space / pressure chamber and pressure connection for the interacting pistons is realized. The present invention focuses on two variants for implementing a variable pressure space for the interacting pistons.

[0023] It is advantageous if the stop disk is arranged radially inside or radially outside the piston. In particular, a radially inside arrangement is advantageous because the piston can be formed integrally with the actuation cap. Better utilization of the installation space, in particular smaller utilization of the installation space, may be achieved with a radially outside arrangement. However, this may have drawbacks during installation.

[0024] If the piston is arranged for bidirectional / alternating pressure, actuation in one axial direction and in the opposite axial direction is possible in a small installation space.

[0025] It has also been found to be advantageous if the stop disc has at least one axial protrusion which is arranged to abut against the axial piston and penetrate one of the pressure chambers, which then results in a targeted configuration and use of space.

[0026] If a large number of axial protrusions protrude from the end face of the stop disc and are distributed over the periphery, jamming of the piston / annular piston in the housing can be effectively prevented, and in particular an evenly distributed arrangement of the axial protrusions has a particularly great advantage in this respect.

[0027] An advantageous embodiment is also characterized in that by means of a circlip fixed in the housing, at least the axial position of the stopping disc is fixed, for example together with a step of the housing.

[0028] It is advantageous if the sliding sleeve is connected to the actuation cap. This also allows for easier assembly. This connection can be permanent or temporary.

[0029] Furthermore, it may be advantageous if axially resiliently configured end stop disks are provided to limit the axial movement of the sliding sleeve / shift sleeve.

[0030] It is advantageous if the end stop discs have an S-shape or a double S-shape in longitudinal cross section along the axis of rotation of the clutch.

[0031] It is also advantageous if the end stop discs are mounted in a preloaded manner.

[0032] It is also advantageous if the end stop discs are attached to the shaft, for example the intermediate shaft.

[0033] 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 fixing ring fixed to the shaft.

[0034] It has proven to be advantageous if the radial extension of the end stop disc is greater than the radial extension of the clutch body.

[0035] It is also advantageous if there is space between the end stop discs and the clutch body.

[0036] It is further advantageous if the fixing ring is arranged in a groove on the outer surface of the shaft at an axially defined position.

[0037] An advantageous embodiment is further characterized in that the end stop discs, i.e. the fixing rings and / or the clutch body, are configured to be at least 10 times (up to 100 times) more elastic in the axial direction.

[0038] It is also advantageous if at least one mechanical locking element between the axially movable component and the axially fixed component is configured and arranged to be able / to lock the sliding sleeve in two different axial positions depending on the operating state.

[0039] 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.

[0040] It is advantageous if the locking element is disposed in a spring-biased seat in the axially fixed (or axially movable) component for selectively engaging in a locking manner between two grooves in the axially movable (or axially fixed) component.

[0041] It has been found to be advantageous if the groove forms a recess which is inclined on both sides.

[0042] It is useful when the locking element is forced to lock when it engages one of the two grooves.

[0043] For particularly good distribution of forces, it has been found useful to use multiple locking elements.

[0044] It is preferred if at least one of the locking elements / the locking element is shaped as a sphere or ball.

[0045] An advantageous embodiment is also characterized in that the two detents, each with a locking element, are at the same radial distance from the axis of rotation of the clutch.

[0046] This is useful if the groove is in a hardened insert.

[0047] The sliding sleeve is also preferably connected to the actuation cap.

[0048] Finally, the present invention provides a DCU / disconnect unit for hydraulically actuated electric axles with a locking element. This invention achieves a significant improvement. Unwanted residual pressure in the shift piston (connection P1 or P2) from the hydraulic system can cause abnormal movement of the shift piston within the pressure chambers P1 and P2 due to the form-fit connection between the shift piston and the sliding sleeve, as well as the movement of the sliding sleeve. Such unwanted movement can have serious consequences for both functionality and functional safety (e.g., tooth breakage, uncontrollable vehicle operation). In hydraulic systems, this can be implemented with additional effort, or in pressure valves, complicated by the use of complex additional valves. This is no longer necessary. At the same time, the controllability and positioning of the shift piston are also not robust due to the complex hydraulic valves. Here, too, an improvement is achieved. The use of a locking element within / with a moving part leads to an improvement in the DCU. The locking element between the shift cylinder and the shift piston can be a single locking element, for example, a slotted wire ring, a formed 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 purpose of both locking elements is to prevent abnormal axial movement of the shift piston, and this is achieved. The axial force is distributed between both locking elements, while at the same time ensuring the end positions of the sliding sleeve and the shift piston. To minimize friction, an axial clearance is ensured between the sliding sleeve and the shift piston.

[0049] Here, an improved cutting unit with hydraulic actuation is introduced, especially for front axles and dual drive E-axles. Due to current knowledge and new concepts using form fits (not friction fits), solutions of this type are still unknown.

[0050] Thanks to hydraulic actuation, the end stops of the shift piston are now easier to control. This means that unacceptable NVH disturbances no longer exist between the sliding sleeve and the clutch body. The solution is to use an S-disc 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 with an appropriate preload between the clutch body and the locking ring. Improved disconnect units with hydraulic actuation are now possible, especially for electric front axles and dual-drive electric axles. The concept of multiple-disc clutches is known on the market but is currently being improved. While the discs are constantly preloaded by the shift piston and the end stops of multiple-disc clutches were the discs themselves, improved variations are possible. Due to current requirements, multiple-disc clutches are being replaced by dog ​​clutches with form-fitting mechanisms. However, end-stop shift noise is avoided. Although the end stop points of the shift piston are still not easy to control due to hydraulic actuation, 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 particular application, which reduces noise at the end stop. The S-disc can be mounted with an appropriate preload between the clutch body and the fixing ring.

[0051] The invention is explained in more detail below with the aid of the drawings. [Brief explanation of the drawings]

[0052] [Figure 1]1 shows a partially illustrated longitudinal section of a clutch according to the invention, in which the two pressure spaces are located radially outside the piston. [Figure 2] This shows the "engagement portion closed" operating position of the clutch in Figure 1. [Figure 3] 3 shows the "open mesh" operating position of the clutch of FIGS. 1 and 2; [Figure 4] 1 shows a clutch according to the present invention in which the pressure chamber is located radially inward of the piston. [Figure 5] The operating positions of the clutch in Figure 4 are "mesh portion closed" (Figure 5) and "mesh portion open" (Figure 6). [Figure 6] The operating positions of the clutch in Figure 4 are "mesh portion closed" (Figure 5) and "mesh portion open" (Figure 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 detail in longitudinal section of a further clutch according to the invention in a second operating position, in which the shift sleeve and the actuation cap are in an axially displaced position relative to FIG. 7; [Figure 9] In FIG. 9 the snap fastening is shown enlarged in longitudinal section, and in FIG. 10 the cantilevered arm is shown enlarged in perspective view in detail in the switching position of the actuation cap. [Figure 10] In FIG. 9 the snap fastening is shown enlarged in longitudinal section, and in FIG. 10 the cantilevered arm is shown enlarged in perspective view in detail in the switching position of the actuation cap. DETAILED DESCRIPTION OF THE INVENTION

[0053] These figures are merely schematic in nature and serve only to understand the invention. Identical elements are provided with the same reference symbols. Features of the individual embodiments can be interchanged.

[0054] Figure 1 shows a clutch 1. The clutch 1 has a piston 2. The piston 2 is configured for bidirectional / 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. Reference is now made to Figures 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. Of course, this can also be achieved vice versa.

[0055] 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 attached to each other. In the clutch 1 of Figures 4-6, the piston 2 and actuation cap 8 form an integral, single-material component.

[0056] 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 its radially outer side and a second seat 12 on its radially inner side.

[0057] As can be seen in Figures 2 and 3, there is a seal 13 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 its "open mesh" operating position, as shown in Figure 3, the axial protrusion 15 extends completely through the second pressure chamber 7 and abuts the piston 2. The axial protrusion 15 protrudes from an end face 16 of the piston 2.

[0058] There is a circlip 17 and a step 18 which directly or indirectly fixes the stopping disc 10 in its central axial position. This is particularly well shown in Figures 5 and 6.

[0059] 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.

[0060] The pressure space sleeve 19 is fixed in place by a pressure space sleeve circlip 20 with an intervening seal in the form of an O-ring 21 .

[0061] Figure 7 shows a clutch 1 with an end stop disc 22, which is axially arranged between a fixed ring 23 and a clutch body 24. These two components are located on the outer surface 25 of an (intermediate) shaft 26. There is also an idler gear 27.

[0062] The end stop disc 22 has an S-shape and is axially elastic. The end stop disc 22 is made of sheet metal. A space 28 is enclosed between the end stop disc 22 and the clutch body 24. The fixing ring 23 is seated in a groove 29 in the outer surface 25.

[0063] There are various locking elements, namely locking element 30 and locking element 31. Both locking element 30 and locking element 31 are configured as balls. Locking element 30 is seated in a locking element receiving groove / groove 32 in housing 3, and locking element 31 is seated in a locking element receiving groove / groove 33. Locking element 30 is intended for locking / locking insertion into a channel / groove 34, and locking element 31 is intended to engage in a similar channel / groove 35 in an insert 36 that is fixed in piston 2. These channels / grooves 34 and 35 have inclined surfaces. The rotation axis is designated by the reference number 37.

[0064] Also on the (intermediate) shaft 26 there is a bearing 38 .

[0065] In FIG. 7 one position of the clutch is assumed, whereas in FIG. 8 the other shift position of the clutch 1 is assumed.

[0066] Also, attention should be paid again to the configuration of the actuation cap 8, which has a base 38 which merges into a cantilevered arm 39 which forms at its free end a snap-fastening 40 which surrounds with an axial clearance a radial projection 41 of the shift / slide sleeve, see also Figure 9.

[0067] 10, the snap-fit ​​end of the cantilevered arm 39 is configured in the style of a clip or gripper, with a slit 42 on one side and a slot 43 on the other side for selectively adjusting the elasticity / stiffness indicated by portions 44 and 45.

[0068] 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.

[0069] The cantilevered arm 39 thereby represents a lever 49 . [Explanation of symbols]

[0070] 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 Fixing 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 Arm 40 Snap fastener 41 Radial protrusion 42 Slits / recesses 43 slots 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) in a manner that allows it to move axially depending on the pressure, said piston (2) being connected to an actuating cap (8) arranged to contact / move a sliding sleeve (9), said actuating cap (8) having a portion configured as a cantilever arm (39) and having a snap-fastening portion (40) at its free end for engaging with said sliding sleeve (9), A clutch (1), characterized in that the cantilevered arms (39) protruding from the base (38) of the actuation cap (8) are spaced apart by slits (42) extending between the cantilevered arms (39) and the base (38), and the slits (42) allow selective adjustment of elasticity / rigidity in the axial and radial directions.

2. 2. A clutch (1) according to claim 1, characterized in that the slits (42) penetrate only partially through the material of the actuating cap (8) in the circumferential direction but completely through the material of the actuating cap in the radial direction.

3. 2. A clutch (1) according to claim 1, characterized in that said cantilevered arm (39) defines a lever (49).

4. 2. The clutch (1) according to claim 1, characterized in that the snap-fastening portion (40) surrounds the radial projection (41) of the sliding sleeve (9) with an axial clearance.

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

6. A clutch (1) for coupling and decoupling a motor to and from the drive train of a motor vehicle, comprising a piston (2) arranged in a pressure-dependent manner between two pressure chambers (6, 7) in a housing (3) so as to be axially movable, said piston (2) being connected to an actuating cap (8) adapted to contact / move a sliding sleeve (9), said actuating cap (8) having a portion configured as a cantilever arm (39) and having a snap-fastening portion (40) at its free end for engaging with said sliding sleeve (9); A clutch (1), characterized in that a slot (43) is provided in said cantilever arm (39).

7. The cantilevered arms (39) protruding from the base (38) of the actuation cap (8) are spaced apart by slits (42) extending between the cantilevered arms (39) and the base (38), and the slits (42) selectively adjust the axial and radial elasticity / rigidity; 7. A clutch (1) according to claim 6, characterized in that said slots (43) extend parallel to said slits (42).

8. 7. A clutch (1) according to claim 6, characterized in that the slot (43) is configured as a rectangular through-opening.

9. A clutch (1) for coupling and decoupling a motor to and from the drive train of a motor vehicle, comprising a piston (2) arranged in a pressure-dependent manner between two pressure chambers (6, 7) in a housing (3), the piston (2) being connected to an actuating cap (8) adapted to contact / move a sliding sleeve (9), the actuating cap (8) having a portion configured as a cantilever arm (39) and having a snap-fastening portion (40) at its free end for engaging with the sliding sleeve (9); A clutch (1), characterized in that the cantilevered arm (39) is configured to include an L-shape.

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