coupling

Abstract

Clutch (1) for a motor vehicle transmission with at least one friction clutch (K1), wherein the friction clutch (K1) is connectable to a motor shaft and to a transmission input shaft, wherein the friction clutch (K1) has a multi-plate clutch pack (3) with several inner plates (5) and several outer plates (6), wherein at least one expanding spring (11) is arranged radially outside friction surfaces formed between the inner plates (5) and the outer plates (6) between at least some of the outer plates (6), wherein the multi-plate clutch pack (3) is axially supported on an abutment (17) designed as a support disk (19) with an external toothing (9) engaging in an outer plate carrier and is actuated by an actuating means (23) designed as an actuating piston (25),wherein both the actuating means (23) and the abutment (17) each have a first pressure area (29) at the radial height of the spreading springs (11) and the lamellar pack (3) is functionally supported or can be supported on the one hand on the first pressure area (29) of the actuating means (23) and on the other hand on the first pressure area (27) of the abutment (17) and wherein both the actuating means (23) and the abutment (17) each have a second pressure area (31, 32) radially spaced from the first pressure area (27, 29), which is formed at the radial height of the friction surfaces formed between the inner lamellae (5) and the outer lamellae (6), characterized in that the support disc (19) is corrugated such that it has the first pressure area (27) and the second pressure area (31), and the actuating piston (25) has tongues at the height of the lamellar pack (4),which form the first printing area (29) and the second printing area (33).

Description

[0001] The invention relates to a clutch, in particular for a transmission of a motor vehicle, preferably a multiple clutch or a double clutch for an automatic or automated double-clutch transmission, with at least one friction clutch, wherein the friction clutch is connectable or connected, on the one hand, to an engine shaft and, on the other hand, to a transmission input shaft, wherein the friction clutch has a disk pack with a plurality of inner disks and a plurality of outer disks, wherein at least one spreading spring is arranged between at least some outer disks radially outside of friction surfaces formed between the inner disks and the outer disks, wherein the disk pack is axially supported on an abutment formed as a support disk with external teeth engaging in an outer disk carrier and is actuable by an actuating means,wherein both the actuating means and the abutment each have a first pressure region at the radial height of the spreading springs, wherein the disk pack is functionally supported or can be supported on the one hand on the first pressure region (29) of the actuating means and on the other hand on the first pressure region of the abutment, and wherein both the actuating means and the abutment each have a second pressure region radially spaced from the first pressure region, which is formed at the radial height of the friction surfaces formed between the inner disks and the outer disks.

[0002] Such a coupling is known from DE 10 2010 044 379 A1.

[0003] Dual clutches distribute the torque to be transmitted, specifically between two different transmission input shafts of a dual-clutch transmission. The first friction clutch, which is preferably connected to the first gear of the first transmission input shaft, is generally subject to higher thermal stress, as this friction clutch must dissipate the heat generated during acceleration. Torque is transmitted from the engine shaft to the two friction clutches.

[0004] The two friction clutches each have a plate pack. The plate pack has outer plates and inner plates. The dual clutch has two actuating pistons and at least one outer plate carrier and preferably two inner plate carriers. The two friction clutches are connectable or can be connected to the engine shaft via the outer plate carrier and to one of the transmission input shafts via one of the inner plate carriers. The actuating pistons are arranged so as to be axially displaceable. The actuating piston serves as the actuating means. A support disk can serve as an abutment to support the plate pack. Various spring designs are used to reset the actuating piston. One known method is to support the actuating piston with spring arrangements arranged outside the plate pack for resetting.

[0005] Furthermore, it is known to arrange expanding springs within the disk pack, i.e., between at least some of the disks of the disk pack. The expanding springs can also cause piston retraction. Different designs for such expanding springs are known, for example, from DE 10 2010 009 672 A1 (coil springs), DE 11 2009 001 177 T5 (wave springs), DE 10 2008 062 645 A1 (elastomers), and DE 101 24 583 A1 (spring clips).

[0006] DE 10 2009 057 353 A1 discloses a multi-plate clutch with a first set of plates and a second set of plates. The first set of plates is connected to a first plate carrier, and the second set of plates is connected in a rotationally fixed manner to a second plate carrier. The two sets of plates are arranged alternately one behind the other in the axial direction and can be brought into frictional engagement with one another. The spreading springs are used as a spring device for separating the plates. The spreading springs are provided for at least one pair of plates consisting of two adjacent plates of the first set of plates. By means of the spreading springs, the two adjacent plates of the pair of plates can be spaced apart from one another in the axial direction when the multi-plate clutch is open, forming an axial distance. The distance is greater than the width of the intervening plates of the second set of plates in the axial direction.The actuating elements, designed as actuating pistons with supporting fingers, and the abutment, designed as a drive plate, are each positioned approximately centrally on the friction surfaces acting between the inner and outer plates. Such a clutch is not yet optimally designed. In some cases, so-called "dipping," i.e., lurching of the plates, can occur, resulting in a drag torque between them.

[0007] A multi-plate clutch with a similarly designed actuating piston is known from EP 1 577 575 A1. This document also discloses a variety of abutment shapes, some of which are block-shaped with large, differently positioned pressure areas, or wave-shaped, each with a pressure area acting on the radially inner or outer edge of the contact surfaces.

[0008] From the aforementioned generic document DE 10 2010 044 379 A1, it is known to provide the actuating piston with a corrugated pressure ring, with which it acts on the disk pack. The corrugation is designed in such a way that a first pressure zone is created radially at the level of the expanding springs, i.e., radially outside the friction surfaces, and – radially spaced from this – a second pressure zone is created centrally of the friction surfaces. This design counteracts the discs on the actuating means side. The abutment, on the other hand, is designed as a convexly curved support ring that rests against the disk pack at the radial height of the center of the friction surface.

[0009] A similar design of the actuating piston is disclosed in DE 10 2005 025 772 A1, in which the abutment is described as a bell with an outwardly bent edge, which rests on the disk pack at the radial height of the friction surface center.

[0010] DE 10 2010 049 504 A1 also discloses an actuating piston designed in this way, but does not disclose a separate abutment. This technically necessary element is not shown in the document, presumably for reasons of graphic simplicity.

[0011] DE 10 2009 012 283 A1 discloses - in various designs of the actuating piston - a support ring fixed to the outer disk carrier, projecting radially inwards as an abutment, which has an axial bulge in the area of ​​the friction surface center with which it rests against the disk pack.

[0012] DE 10 2010 021 036 A1 discloses an actuating piston with a flat contact ring surface extending from the outer edge of the plates to the center of the friction surfaces. The abutment is a ring extending radially outward into the axial space between two clutches, with a symmetrical bead on its inner circumference. The bead is located at the radial height of the center of the friction surface.

[0013] DE 101 46 606 A1 combines a bell-shaped design of the actuating piston and a design of the abutment as an L-shaped ring projecting from radially outside to radially inside, whereby in both cases the comparatively sharp contact edges are located in the central area of ​​the friction surfaces.

[0014] DE 10 2009 050 998 A1 discloses two axially adjacent clutches, between which an abutment designed as a corrugated ring with two pressure areas is arranged, the first of which is located in the center of the friction surfaces and the second of which is located in the radially inner edge area of ​​the friction surfaces.

[0015] JP H04-366 031 A discloses a clutch whose pressure piston has an annular recess on its side adjacent to the disk pack, creating two separate pressure zones. The first is located at the level of the radially inner area of ​​the friction surfaces, and the second is located at the level of the radially outer area of ​​the friction surfaces and extends radially outside the friction surfaces. The abutment, on the other hand, forms a uniform pressure zone extending across the entire width of the friction surface and radially outward beyond it.

[0016] In the clutch disclosed in JP 2007-315551 A, both the pressure piston and the abutment each form a uniform pressure area that extends across the entire friction surface width and radially outward beyond it. The same applies to the clutches disclosed in US 3,412,834 A, US 4,940,124 A, US 2009 / 0314601 A1, and JP H08-21458 A. Such designs are heavy and require a lot of material.

[0017] The invention is based on the object of simplifying the overall design of the coupling.

[0018] The object underlying the invention is achieved in that the support disc is corrugated in such a way that it has the first pressure region and the second pressure region, and the actuating piston has tongues at the level of the plate pack that form the first pressure region and the second pressure region. This has the advantage that, despite a significantly simplified overall design, dishing caused by the force of the expanding springs is avoided. The expanding springs can generate high forces to cause the piston to return without this leading to dishing of the plates, in particular of the loaded outer plates. The clearance between the plates is not reduced as a result. An increased drag torque is avoided.The first pressure zone provides the expanding springs with a pressure line in the plate pack, so that the spring-loaded plates can be functionally supported on the abutment and the actuating means via the expanding springs. The expanding springs are arranged between the outer plates. The expanding springs are arranged radially outside the inner plates. The first pressure zone is formed on the actuating means, for example, an actuating piston, and an abutment, for example, a corresponding support disc, at the level of the expanding springs (seen in the radial direction) outside the inner plates. The disadvantages mentioned above are therefore avoided and corresponding advantages are achieved.

[0019] There are now numerous possibilities for advantageously designing and developing the coupling according to the invention. Reference is made to the claims subordinate to claim 1. The drawing shows: Fig. 1 in a schematic, sectional detailed view of a double clutch with two friction clutches.

[0020] In Fig. 1 shows a clutch 1, particularly for a transmission of a motor vehicle. Clutch 1 is designed here as a dual clutch 2 for an automatic or automated dual-clutch transmission (not shown in detail). A multiple clutch design is also conceivable.

[0021] A first friction clutch K1 and a second friction clutch K2 are clearly visible. The two friction clutches K1 and K2 can be connected to a motor shaft (not shown in detail). The first and second friction clutches K1 and K2 can each be connected to a transmission input shaft (not shown in detail) of the dual-clutch transmission. The friction clutches K1 and K2 are designed as wet-running friction clutches K1 and K2.

[0022] The friction clutches K1 and K2 each have a plate pack 3, 4. The plate pack 3 has inner plates 5 and outer plates 6. The plate pack 4 has inner plates 7 and outer plates 8. The inner plates 5, 7 and the outer plates 6, 8 are each alternately stacked. The outer plates 6, 8 have external teeth 9. The inner plates 5, 7 have internal teeth 10. The outer plates 6, 8 and / or the inner plates 5, 7 can have a friction lining (not further specified).

[0023] At least one expanding spring 11 is arranged between at least some of the lamellae, preferably between all relevant lamellae. In the illustrated embodiment, several expanding springs 11 are provided. The expanding springs 11 are each arranged between the outer lamellae 6 of the first lamella pack 3 and between the outer lamellae 8 of the second lamella pack 4. The expanding springs 11 are designed as wave springs 12. The wave spring 12 has corrugated regions (not designated in more detail) in the axial direction, with which it rests against two adjacent outer lamellae 6 and 8, respectively. The use of wave springs 12 has the advantage of low hysteresis.

[0024] In an alternative embodiment, the expansion springs 11 are designed as disc springs. One function of the expansion springs 11 is to separate the plates and thereby reduce the risk of drag torques between the adjacent inner plates 5, 7 and outer plates 6, 8.

[0025] The disk pack preferably has two end disks 13, 14 and 15, 16, respectively. In the illustrated embodiment, the end disks 13 to 16 are designed as outer disks 6 and 8, respectively. The end disks 13 to 16 have a greater width than the outer disks 8 arranged between them.

[0026] The outer plates 6, 8 engage with their external teeth 9 in an outer plate carrier (not shown). In the illustrated embodiment, the dual clutch 2 has a common outer plate carrier for both friction clutches K1, K2. In an alternative embodiment, the two friction clutches K1 and K2 could be arranged radially to one another rather than axially adjacent to one another. The outer plate carrier is functionally connectable to the motor shaft. The internal teeth 10 of the inner plates 5 engage in a first inner plate carrier (not shown), and the internal teeth 10 of the second inner plates 7 engage in a second inner plate carrier. The inner plate carriers are functionally connectable to corresponding transmission input shafts (not shown).

[0027] The disk pack 3 is supported on an abutment 17, and the disk pack 4 is supported on an abutment 18. The two abutments 17, 18 are essentially identical in design. The abutments 17, 18 each have a support disk 19, 20. The support disks 19, 20 preferably have external teeth (not designated in more detail), with the support disks 19, 20 engaging with the external teeth (not designated in more detail) in the outer disk carrier. Each of the support disks 19, 20 is secured against axial displacement, in particular with a retaining ring 21, 22. The retaining ring 21, 22 engages in a corresponding groove in the outer disk carrier.

[0028] On the side of the disk pack 3, 4 facing away from the abutment 17, 18, an actuating means 23, 24 in the form of an actuating piston 25, 26 engages the disk pack 3, 4. By axially displacing the actuating piston 25, 26 or actuating means 23, 24, the friction clutch K1 or K2 can be opened and closed. The actuating piston 25, 26 counteracts the force of the expanding springs 11.

[0029] The disadvantages mentioned above are now avoided in that the abutment 17 and the actuating means 23 have a first pressure region 27, 29 at the radial height of the spreading springs 11, wherein the disk pack 4 is supported or can be supported on the first pressure region 27, 28, 29, 30. The abutment 17 has the first pressure region 27. The second abutment 18 has the first pressure region 28. The first actuating means 23 has the first pressure region 29. The second actuating means 24 has the first pressure region 30. The first pressure regions 29, 27 are at the height of the spreading springs 11 of the first disk pack 3. This avoids drag torques.Even if the spreading springs 11 apply strong forces to the actuating piston 25 for resetting, the slats, in particular the outer slats 6, are functionally effectively supported via the spreading springs 11 on the two first pressure areas 27, 29, whereby a dishing of the slats, in particular the outer slats 6, is prevented.

[0030] The abutment 17, 18 and the actuating means 23 and 24 further have a second pressure region 31, 32, 33, 34. The second pressure region 31, 32, 33, 34 is formed at the (radial) height of the overlapping friction surfaces of the inner plates 5, 7 and the outer plates 6, 8. The second pressure region 31, 32, 33, 34 is formed, in particular, radially centrally relative to the overlap area of ​​the inner plates 5, 7 and the outer plates 6, 8. The first and second pressure regions 27 to 29 and 31 to 34, respectively, support the plate packs 3, 4 both centrally and at the height of the spreading springs 11. This prevents the plates from warping. Drag torques are accordingly prevented.

[0031] The support disc 19, 20 is correspondingly corrugated in the radial direction. The support ring 21, 22 is arranged substantially at the level of the expanding springs 11. In the illustrated clutch 1, the actuating piston 25 also has a correspondingly corrugated shape at the level of the disk pack 3. However, this does not correspond to the present invention. In an alternative embodiment according to the invention, but not shown, the actuating piston 26 has several tongues for forming the first pressure region or the second pressure region 34.

[0032] The first and second pressure regions 27 to 29 and 31 to 34 are spaced apart from one another, particularly in the radial direction.

[0033] The invention allows the use of expanding springs 11 with high spring force without deforming the separate inner plates 5, 7 and outer plates 6, 8. Even if expanding springs 11 are provided in the plate packs 3, 4, which forcibly space the inner plates 5, 7 and outer plates 6, 8, their force cannot lead to a cupping of the inner plates 5, 7 and the outer plates 6, 8. Corresponding drag torques are avoided. This allows the expanding springs 11 to also be used as return springs for the actuating means 23, 24, i.e., the actuating pistons 25, 26, without negatively affecting the drag torque. The plate packs 3, 4 are not only supported on the average friction diameter by the corresponding second pressure area 31 to 34, but are also supported in the pressure line of the spreading springs 11, i.e. in the first pressure area 27, 28, 29, to avoid dishing.The opposing first pressure areas 27, 28 and 29 respectively form corresponding abutments which prevent the disk packs 3 and 4 from warping. List of reference symbols 1 clutch 2 dual clutch 3 slat pack 4 slat pack 5 inner lamella 6 outer slats 7 inner lamella 8 outer slats 9 External gearing 10 Internal gearing 11 Spreader spring 12 wave spring 13 End lamella 14 End slat 15 End slat 16 End slat 17 abutments 18 abutments 19 Support disc 20 support disc 21 Retaining ring 22 Retaining ring 23 Actuating means 24 Actuating devices 25 actuating pistons 26 actuating pistons 27 first printing area 28 first printing area 29 first printing area 31 second printing area 32 second pressure area 33 second printing area 34 second printing area K1 friction clutch K2 friction clutch

Claims

[1] Clutch (1) for a transmission of a motor vehicle with at least one friction clutch (K1), wherein the friction clutch (K1) is connectable or connected, on the one hand, to an engine shaft and, on the other hand, to a transmission input shaft, wherein the friction clutch (K1) has a disk pack (3) with a plurality of inner disks (5) and a plurality of outer disks (6), wherein at least one spreading spring (11) is arranged between at least some outer disks (6) radially outside of friction surfaces formed between the inner disks (5) and the outer disks (6), wherein the disk pack (3) is axially supported on an abutment (17) designed as a support disk (19) with an external toothing (9) engaging in an outer disk carrier and is actuable by an actuating means (23) designed as an actuating piston (25),wherein both the actuating means (23) and the abutment (17) each have a first pressure region (29) at the radial height of the spreading springs (11), and the disk set (3) is functionally supported or can be supported on the one hand on the first pressure region (29) of the actuating means (23) and on the other hand on the first pressure region (27) of the abutment (17), and wherein both the actuating means (23) and the abutment (17) each have a second pressure region (31, 32) radially spaced from the first pressure region (27, 29) formed at the radial height of the friction surfaces formed between the inner disks (5) and the outer disks (6), characterized bythat the support disc (19) is corrugated in such a way that it has the first pressure region (27) and the second pressure region (31), and the actuating piston (25) has tongues at the level of the disk pack (4) which form the first pressure region (29) and the second pressure region (33). [2] Coupling according to claim 1, characterized by that the second pressure region (31, 32) is formed radially centrally relative to the friction surfaces. [3] Coupling according to one of the preceding claims, characterized by that the spreading springs (11) are designed as wave springs (12). [4] Coupling according to one of the preceding claims, characterized by that the restoring force of the spreading springs (11) is designed such that the actuating means (23) can be reset by means of the spring force of the spreading springs (11). [5] Coupling according to one of the preceding claims, characterized bythat the support disc (19) is secured at least on one side against axial displacement on the outer disc carrier by a retaining ring (21). [6] Coupling according to one of the preceding claims, characterized by that the outer plates (6) are arranged on a common outer plate carrier at the same radial height. [7] Coupling according to one of the preceding claims, characterized by that the clutch (1) is designed as a double clutch (2) and has two friction clutches (K1, K2).

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