DE112014001037B4 - friction clutch - Google Patents

Abstract

Friction clutch for coupling a drive shaft of a motor vehicle engine to a transmission input shaft of a motor vehicle transmission, with a counter-plate for introducing a torque, a pressure plate (14) that can be displaced relative to the counter-plate for frictionally pressing a clutch disc for dissipating the torque, a clutch cover (12) connected to the counter-plate, at least partially Covering the pressure plate (14), a lever spring (18), in particular a plate spring, supported pivotably on the clutch cover (12), for moving the pressure plate (14), a servo spring (26), in particular designed as a lever spring, for reducing a pressure plate for moving the pressure plate (14) the required actuating force that can be applied by an actuating system in the event of wear and a support element (28), in particular designed as a retaining hook (28), spaced apart from the pressure plate (14) for axially supporting the servo spring (26), the support element (28) having an axial direction and a support stop (34) protruding in the radial direction and/or essentially in the tangential direction for axial abutment on a first force edge (38) of the servo spring (26), the lever spring (18) having a spring opening ( 30) and the web (32) of the support element (28) protrudes through the spring opening (30), characterized in that the servo spring (26) is designed in one piece with the lever spring (18), the servo spring (26) in particular as a spring tongue of the lever spring (18) protruding in the radial direction.

Description

The invention relates to a friction clutch, with the aid of which a drive shaft of a motor vehicle engine can be coupled to a transmission input shaft of a motor vehicle transmission.

Out of DE 10 2006 058 311 A1 and EP 1 980 766 A1 a friction clutch is known in each case, which has a pressure plate that can be displaced axially by a lever spring for frictionally pressing a clutch disk between the pressure plate and a counterplate. A clutch cover is firmly connected to the counterplate, through which a screw screwed to the pressure plate is passed. On the side of the clutch cover pointing away from the pressure plate, the screw has a screw head which is supported on the clutch cover via a plate spring arranged between the clutch cover and the screw head. The actuating force required to actuate the friction clutch when the clutch disc is worn can be influenced by the diaphragm spring contacting the clutch cover and the screw.

There is a constant need to keep the actuating force required to actuate a friction clutch low, even when wear occurs, without increasing the space requirement.

Furthermore, from the DE 11 2007 000 229 T5 a friction clutch is known, which can be read on the preamble of claim 1. From the WO 98/25043 A1 a friction clutch is known, which can be read on the preamble of claim 8.

It is the object of the invention to indicate measures which enable a small actuating force required to actuate a friction clutch, even when wear occurs, and a small installation space requirement for a friction clutch.

The object is achieved according to the invention by a friction clutch having the features of claim 1 and a friction clutch having the features of claim 8. Preferred developments of the invention are specified in the subclaims, which individually or in combination can represent an aspect of the invention.

According to the invention, a friction clutch for coupling a drive shaft of a motor vehicle engine to a transmission input shaft of a motor vehicle transmission is provided with a counter-plate for introducing a torque, a pressure plate that can be displaced relative to the counter-plate for frictionally pressing a clutch disc for dissipating the torque, a clutch cover connected to the counter-plate for at least partial covering the pressure plate, a lever spring, in particular a cup spring, pivotably supported on the clutch cover, for moving the pressure plate, a servo spring, in particular designed as a lever spring, for reducing an actuating force that is required for moving the pressure plate and can be applied by an actuating system in the event of wear and a, in particular designed as a retaining hook , spaced apart from the pressure plate for the axial support of the servo spring, the support element having a web running in the axial direction and a support stop protruding in the radial direction and/or essentially in the tangential direction for axial contact with a first force edge of the servo spring, the lever spring having a Has spring opening and the web of the support element protrudes through the spring opening.

Due to the support element projecting through the lever spring, the servo spring can be provided in an otherwise unused volume of the friction clutch, so that a small actuating force required to actuate a friction clutch is made possible even when wear occurs and a small installation space requirement for the friction clutch is made possible. In particular, it is possible to avoid an increase in the space required for the friction clutch in the axial direction and/or in the radial direction. Furthermore, it can be provided that the support element is used for centering and/or as a stop for the lever spring acting in the circumferential direction and/or in the radial direction, so that it is possible to save on additional centering elements. The servo spring can act radially outside of the support element or radially inside of the support element with a second force edge of the servo spring that is different from the first force edge on the cup spring or the pressure plate. The servo spring and/or the support element do not necessarily have to encompass the lever spring radially on the outside and/or protrude from the clutch cover in an axial direction pointing away from the pressure plate. At the same time, with the help of the servo spring, when the friction clutch wears, in particular when friction linings provided between the counterplate and the clutch disc and/or between the pressure plate and the clutch disc become thinner due to wear and the stroke of the pressure plate to close the friction clutch increases, an otherwise occurring increase the required operating force, in particular Release force, are at least partially compensated for actuating the friction clutch. The maximum required actuation force occurring over the wear area of the friction clutch can be reduced and kept low as a result. This makes it possible to save on a wear adjustment device for compensating for a travel of the pressure plate that increases due to wear, for example with the aid of a ramp system provided between the pressure plate and the lever spring and/or between the lever spring and the clutch cover, without an excessive increase in the maximum required actuating force that occurs to have to accept. By saving the wear adjustment device, the space required for the friction clutch can be further reduced.

The support stop has in particular a contact surface pointing away from the pressure plate for contact with the servo spring. The servo spring is in particular a separate component from the lever spring. The support stop is preferably spaced apart from the lever spring in the axial direction, with the support stop being particularly preferably positioned at a distance from the lever spring over the entire wear area of the friction clutch. In particular, only the web of the support element is provided at a common axial height of the lever spring, ie only the web of the support element is provided within the spring opening. Since the support element is at a distance from the pressure plate, there is no connection, for example a screw connection, between the support element and the pressure plate. In particular, this makes it possible to reduce the number of components and/or to save on machining steps, in particular the production of an internal thread in the pressure plate. Furthermore, the servo spring can essentially act directly on the lever spring, so that intermediate components provided in the force flow between the servo spring and the lever spring can be saved. This prevents intermediate components from being able to impair the spring effect that can be applied by the servo spring to the lever spring due to their own elastic behavior under the influence of force. For example, it is not necessary for the servo spring to exert a spring force on the pressure plate so that the pressure plate can transmit this spring force to the lever spring in order to reduce the actuating force in the wear area. Instead, the flow of force between the servo spring and the lever spring can be routed past the pressure plate, resulting in a cost-effective and space-saving structure for the friction clutch. In particular, the maximum actuating force to be provided for actuating the friction clutch can be reduced with the aid of the servo spring, so that an actuating system for generating the actuating force can be dimensioned to be smaller and more space-saving. It is possible here that the smaller installation space requirement for the actuating system does not lead to an increased installation space requirement for the rest of the friction clutch. In particular, the servo spring is designed in such a way that the servo spring builds up an ever increasing spring force, which points in the direction of the actuating force, as the wear of friction linings increases in the non-actuated state of the friction clutch. If, when the friction clutch is actuated, the lever spring covers an ever greater pivoting path as the wear of the clutch disc increases, part of the force required to move the pressure plate over an ever increasing stroke path can be provided by the servo spring, so that in particular an increase in the Actuating force can be compensated for example by setting up the lever spring designed as a plate spring.

The servo spring can be designed in particular as a disk spring. For this purpose, the servo spring can be designed, for example, as an encircling, conically shaped ring. In particular, the servo spring can provide a spring force that counteracts the lever spring. The spring system made up of lever spring and servo spring can thereby in particular provide an overall spring characteristic which essentially corresponds to a lever spring which is stiffer than the lever spring. The servo spring preferably has projections that protrude radially outwards and/or radially inwards and form the first force edge or the second force edge. For this purpose, the servo spring can have, for example, a circumferential, conically shaped, ring-shaped disk spring area, which in particular provides a large part of the spring effect of the servo spring. Due to the protruding projections, the servo spring can, for example, be inserted into corresponding recesses and/or projections of the support element so that it cannot rotate, in order to simplify the assembly of the friction clutch. Furthermore, the lever spring can in particular have spring tongues that protrude radially inwards or radially outwards, which preferably protrude from a circumferential ring, with the servo spring being able to be supported with the protruding lugs on the spring tongues of the lever spring. The radial position of the respective force edge can be easily adjusted by the approaches. Furthermore, the spring properties of the servo spring can be adjusted through the dimensioning, in particular the radial extent, of the respective projections and/or a circumferentially closed ring with little design and manufacturing effort.

The spring opening of the lever spring designed in particular as a disc spring can be designed as an opening in the material of the lever spring, which is completely continuous in the axial direction, ie essentially parallel to the axis of rotation of the friction clutch. The spring opening can be designed, for example, as an opening with a peripherally closed edge, in which case the opening can be designed as a bore or a punched-out area, for example. Preferably, the lever spring has essentially radially extending spring tongues, which in particular project radially from a closed ring, which preferably acts as a disc spring. In this case, the spring opening is formed in particular by a gap provided between two spring tongues that follow one another in the circumferential direction. As a result, the spring opening is designed to be open in a radial direction. If necessary, the gap provided between two subsequent spring tongues can widen to accommodate the retaining hook. As a result, the retaining hook can be made wider than the rest of the width of the gap, particularly in the circumferential direction, so that the retaining hook can provide a sufficiently large contact surface for contact with the servo spring, which is preferably dimensioned so large that the servo spring frictionally engages during operation of the friction clutch twisting can be secured.

The counter-plate of the friction clutch can be configured in particular by a flywheel, which can be non-rotatably connected, for example, to a crankshaft of a motor vehicle engine. In particular, it is possible to use the friction clutch for a dual clutch, in which case the counterplate can be formed in particular by a common central plate of the dual clutch, so that this central plate can form a counterplate for a friction clutch on both axial sides. The clutch cover is preferably firmly connected to the counterplate, for example by screwing or riveting. In particular, the clutch disk provided in the axial direction between the pressure plate and the counterplate can be connected in a torque-proof manner to a transmission input shaft of a motor vehicle transmission, for example via splines. In particular, the clutch disk can have friction linings that wear out over the service life and can become thinner as a result. Preferably, the clutch disk has a lining spring system for the friction linings, which allows the friction clutch to be closed gently and, in particular when the friction clutch is in the closed state, provides a spring force for opening the friction clutch. A restoring spring connected to the pressure plate and the clutch cover or the counter-plate is particularly preferably provided for positioning the pressure plate in an open position when no force is applied to the pressure plate by the lever spring. If the friction clutch is closed ("normally closed") when an actuating force is not applied to the lever spring by an actuating system, the pressure plate can follow the lever spring by the return spring if the lever spring pivots into a position due to an actuating force applied by the actuating system to the lever spring is, which corresponds to an open position of the friction clutch. The lever spring can in particular be pivoted about an annular, circumferential pivot point, the annular, circumferential pivot point preferably being defined by at least one wire ring supported on the clutch cover.

In particular, at least one spacer bolt, preferably at least three spacer bolts, is connected to the clutch cover for axial contact with a second force edge of the servo spring that is different from the first force edge, the spacer bolt protruding in particular through the lever spring. Due to the spacer bolt, the servo spring can hit the spacer bolt and lift off the lever spring from a defined angular position of the lever spring. This makes it possible for the servo spring to act and become effective only from a defined angular position of the lever spring on the lever spring, while in the other angular position range of the lever spring the effectiveness of the servo spring is prevented by striking the spacer bolt. The course of the characteristic curve of the actuating force via the angular position of the lever spring and/or the axial position of the pressure plate displaced by the lever spring can thus be set section by section, with the spring force provided by the servo spring being effective in one section of the characteristic curve and not in another section of the characteristic curve . The course of the characteristic curve of the actuating force can be made more uniform as a result. Furthermore, it can be provided that the spacer bolt is used for centering and/or as a stop for the lever spring acting in the circumferential direction and/or in the radial direction, so that it is possible to save on additional centering elements and/or components provided as centering elements at the same time as spacer bolts for the Use servo spring.

The support element is preferably designed in one piece with the clutch cover. As a result, the support element can be designed as a retaining hook bent from the material of the clutch cover. The support element can then preferably be produced by stamping and non-cutting bending, so that cutting processing steps can be avoided.

In one embodiment, it is provided in particular that the servo spring is axially supported on an outside pointing away from the pressure plate in the axial direction with a second force edge that is different from the first force edge, with the support element being guided through the clutch cover so that it can be moved relative to the clutch cover. As a result, the servo spring does not act directly, but indirectly via the movable support element on the lever spring. The maximum insertion depth of the support element into the clutch cover can be specified by striking a radially protruding shoulder of the support element on the clutch cover.

According to the invention, the servo spring is configured in one piece with the lever spring, with the servo spring being configured in particular as a spring tongue of the lever spring that protrudes in the radial direction. The number of components can be reduced as a result. Furthermore, the servo spring can thereby be provided essentially completely with the lever spring at a common height, so that essentially no separate installation space has to be provided for the servo spring.

In particular, when the friction clutch is in the closed state, the lever spring acts directly or indirectly on a first radius on the clutch cover and on a second radius directly or indirectly on the pressure plate, with the support element radially inside both the first radius and the second radius or radially outside both is arranged to the first radius and to the second radius. As a result, the support element and/or the servo spring can be positioned in a radial area where they do not impair the displacement of the pressure plate with the aid of the lever spring. Furthermore, it is possible to design the lever spring in the area between the first radius and the second radius as a substantially completely closed ring in the manner of a disk spring. Recesses in the plate spring, in particular the spring opening for the support element to pass through, can be kept out of the area of the lever spring running in the circumferential direction between the first radius and the second radius, so that the entire radial area between the first radius and the second radius can be filled with the material of the Lever spring can be filled. The lever spring is thus made comparatively stiff between the first radius and the second radius, so that when the friction clutch is actuated, a correspondingly high lever effect can be achieved, which is correspondingly slightly impaired by the inherent spring behavior of the lever spring.

The support stop of the support element is preferably arranged in the axial direction at the level of the pressure plate, with the servo spring acting on the pressure plate in particular with a second force edge of the servo spring that is different from the first force edge. The support stop can in particular be arranged radially outside or radially inside a friction surface of the pressure plate pointing towards the counter-plate. In the closed state of the friction clutch, the friction surface of the pressure plate can create a frictional connection with a clutch disk that is to be pressed between the counterplate and the pressure plate. Coming from the clutch cover in particular, the support stop can protrude so far into the friction clutch that the support stop not only runs through the lever spring, but also extends into the axial height area of the friction clutch. The servo spring can thereby contact the pressure plate and act indirectly via the pressure plate on the lever spring with its spring force in order to influence the actuating force required to actuate the pressure plate.

The support element particularly preferably has a limit stop pointing towards the pressure plate for striking against the pressure plate in an extreme axial position of the pressure plate. In the case of a support element that can be moved relative to the clutch cover, the insertion depth of the support element can be limited as a result. In the case of a support element designed to be non-moving with the clutch cover, an extreme position of the pressure plate, for example a maximum open position of the friction clutch, can be specified by the limit stop. For example, the pressure plate can be pressed against the limit stop formed by the support element by a restoring spring acting on the pressure plate, so that relative movements and/or rattling noises can be avoided without having to provide the lever spring for this purpose.

The invention also relates to a friction clutch for coupling a drive shaft of a motor vehicle engine to a transmission input shaft of a motor vehicle transmission, with a counter-plate for introducing a torque, a pressure plate that can be displaced relative to the counter-plate for frictionally pressing a clutch disc for dissipating the torque, a clutch cover connected to the counter-plate for at least partial covering of the pressure plate, a lever spring, in particular a cup spring, pivotably supported on the clutch cover, for moving the pressure plate, and a servo spring, in particular designed as a lever spring, for reducing a pressure plate for moving the pressure plate required actuating force that can be applied by an actuating system in the event of wear, the clutch cover having a first holding surface pointing towards the pressure plate for contact with the servo spring and a second holding surface pointing away from the pressure plate for contact with the servo spring, with the servo spring between the first holding surface and the second holding surface is secured axially. Due to the servo spring used between the first holding surface and the second holding surface of the clutch cover, the position of the servo spring is predetermined without an additional component being required, so that a small actuating force required to actuate a friction clutch is made possible, even when wear occurs, and a small installation space requirement for the friction clutch is made possible. A part, in particular a lug or several lugs, can protrude from the servo spring in the radial direction and acts directly or indirectly on the lever spring in order to influence the actuating force required to actuate the pressure plate.

In particular, the clutch cover and/or the servo spring has at least one assembly window for axial insertion past the first mounting surface and/or the second mounting surface of the clutch cover, the servo spring for positioning the servo spring between the first mounting surface and the second mounting surface relative to the clutch cover in the circumferential direction is rotatable. As a result, the servo spring can initially be inserted in the axial direction without hitting the component forming the first holding surface and/or the second holding surface. The mounting window is large enough to avoid hitting it. After the servo spring has been moved axially past the component provided in the assembly path, the servo spring can be rotated in the circumferential direction to such an extent that part of the servo spring is positioned between the first holding surface and the second holding surface. In this position, the servo spring is held captive against falling out in the axial direction. The servo spring is preferably held in a frictionally engaged manner between the first holding surface and the second holding surface by its own spring action, so that undesired twisting during operation of the friction clutch can be avoided.

Preferably, the first holding surface and/or the second holding surface is formed by a tab bent out of the material of the clutch cover. The tab is then preferably produced by stamping and non-cutting bending, so that cutting processing steps can be avoided.

Particularly preferably, when the friction clutch is in the closed state, the lever spring acts directly or indirectly on the clutch cover on a first radius and directly or indirectly on the pressure plate on a second radius, with the servo spring radially outside both the first radius and the second radius or between the first radius and the second radius engages the lever spring. In particular, the servo spring can be held essentially radially outside the lever spring between the holding surfaces and protrude radially inward up to the lever spring. The structural space radially within the first and second radius is not required. If the servo spring acts on the lever spring radially outside of the first and second radius, the lever spring can have at least one extension piece protruding radially outwards, on which the servo spring can act.

According to the invention, the lever spring engages in the closed state of the friction clutch directly or indirectly on a first radius on the clutch cover and on a second radius directly or indirectly on the pressure plate, the first radius being larger than the second radius. As a result, the friction clutch can be designed in particular as a so-called “pulled clutch”.

In all of the above-described embodiments of the friction clutch, it can preferably be provided that the lever spring, when the friction clutch is in the closed state, acts directly or indirectly on the clutch cover on a first radius R ₁ and on the pressure plate on a second radius R ₂ , with the servo spring acts directly or indirectly on the lever spring on a third radius R ₃ , where 0.00≦|R ₂ -R ₃ |/R ₂ ≦0.30, in particular 0.01≦|R ₂ -R ₃ |/R ₂ ≦ 0.25, preferably 0.05≦|R ₂ -R ₃ |/R ₂ ≦0.15 and particularly preferably 0.07≦|R ₂ -R ₃ |/R ₂ ≦0.10. As a result, the servo spring can act on the lever spring comparatively close to the second radius on which, for example, the lever spring acts on an actuating cam of the pressure plate that protrudes in the axial direction. Impairment of the spring effect of the servo spring on the lever spring due to elastic deflection of the lever spring can be reduced or even eliminated as a result.

Particularly preferably, the servo spring acts on an axial side of the lever spring pointing toward the pressure plate or on an axial side of the lever spring pointing away from the pressure plate. Depending on whether the servo spring provides a spring force in the direction of the pressure plate or away from the pressure plate, the servo spring can act on one or the other axial side of the lever spring. In particular, the servo spring depending on requirements tion profile and / or existing space be configured as a compression spring or tension spring.

The invention also relates to a drive train of a motor vehicle with a drive shaft of a motor vehicle engine, at least one transmission input shaft of a motor vehicle transmission and a friction clutch, which can be designed and developed as described above, for coupling the drive shaft to the transmission input shaft. Due to the support element of the friction clutch protruding through the lever spring, the servo spring can be provided in an otherwise unused volume of the friction clutch, so that a small actuating force required to actuate a friction clutch is made possible even when wear occurs, and a small installation space requirement for the drive train is made possible.

• 1: eine schematische perspektivische Schnittansicht einer Reibungskupplung in einer ersten Ausführungsform,
• 2: eine schematische Schnittansicht der Reibungskupplung aus 1,
• 3: eine schematische Schnittansicht einer Reibungskupplung in einer zweiten Ausführungsform,
• 4: eine schematische Schnittansicht einer Reibungskupplung in einer dritten Ausführungsform,
• 5: eine schematische Schnittansicht einer Reibungskupplung in einer vierten Ausführungsform,
• 6: eine schematische Schnittansicht einer Reibungskupplung in einer fünften Ausführungsform,
• 7: eine schematische Schnittansicht einer Reibungskupplung in einer sechsten Ausführungsform,
• 8: eine schematische Schnittansicht einer Reibungskupplung in einer siebten Ausführungsform,
• 9: eine schematische Schnittansicht einer Reibungskupplung in einer achten Ausführungsform,
• 10: eine schematische Schnittansicht einer Reibungskupplung in einer neunten Ausführungsform und
• 11: eine schematische Schnittansicht einer Reibungskupplung in einer zehnten Ausführungsform.

In the following, the invention is explained by way of example with reference to the attached drawings using preferred exemplary embodiments, it being possible for the features presented below to represent an aspect of the invention both individually and in combination. Show it:

• 1 : a schematic perspective sectional view of a friction clutch in a first embodiment,
• 2 : a schematic sectional view of the friction clutch 1 ,
• 3 : a schematic sectional view of a friction clutch in a second embodiment,
• 4 : a schematic sectional view of a friction clutch in a third embodiment,
• 5 : a schematic sectional view of a friction clutch in a fourth embodiment,
• 6 : a schematic sectional view of a friction clutch in a fifth embodiment,
• 7 : a schematic sectional view of a friction clutch in a sixth embodiment,
• 8th : a schematic sectional view of a friction clutch in a seventh embodiment,
• 9 : a schematic sectional view of a friction clutch in an eighth embodiment,
• 10 : a schematic sectional view of a friction clutch in a ninth embodiment and
• 11 : a schematic sectional view of a friction clutch in a tenth embodiment.

In the 1 Friction clutch 10, only partially shown, has a clutch cover 12, which can be connected to a counterplate, not shown, for example by screwing and/or riveting. The clutch cover 12 at least partially covers a pressure plate 14 which can be displaced in the axial direction with the aid of a lever spring 18 embodied as a cup spring with a plurality of radially projecting spring tongues 16 . The lever spring 16 can be pivoted about an annular pivot point. For this purpose, the lever spring 16 is supported on the clutch cover 12 via a closed wire ring 20 which defines the pivot point. When an actuating force is introduced into the lever spring 18 via the spring tongues 16, the lever spring 18 is pivoted on the wire ring 20 and presses against a cam 22 of the pressure plate 14, as a result of which the pressure plate 14 is displaced relative to the clutch cover 12. If no actuating force is applied, the pressure plate 14 can be positioned in a defined, in particular open, initial position with the aid of a return spring 24 connected to the pressure plate 14 and the clutch cover 12 and configured in particular as a leaf spring. In order to at least partially compensate for an increase in the actuating force due to wear of the friction linings of the friction clutch, a servo spring 26 designed in particular as a plate spring is provided, which is supported in particular with pretension on the clutch cover 12 and the lever spring 18 . The servo spring 26 is provided radially inward of the pivot point of the lever spring 18 and/or radially inward of the point of application of the lever spring on the cam 22 .

As in 2 shown, the clutch cover 12 has, on a radially inner edge, retaining hooks 28 that protrude in the axial direction and each project through a spring opening 30 provided between two spring tongues 16 that are adjacent in the circumferential direction. The retaining hook 28 has a web 32 which protrudes through the spring opening 30 and from which a support stop 34 protrudes. The support stop 34 has a contact surface 36 pointing away from the pressure plate 14 and on which a first force edge 38 of the servo spring 26 is supported. In the exemplary embodiment shown, the support stop 34 protrudes from the web 32 essentially in the tangential direction, so that the web 32 forms a stop for the defined positioning of the lever spring 18 in the circumferential direction. The servo spring 26 is supported on the lever spring 18 via a second force edge 40 , the second force edge 40 being provided on a larger radius than the first force edge 38 . In the illustrated Embodiment, the point of the servo spring 26 is provided on the lever spring 18 close to the cam 22. In the exemplary embodiment shown, a spacer bolt 42 riveted to the clutch cover 12 is also provided, against which the second force edge 40 of the servo spring 26 rests from a certain angular position of the lever spring 18 and no longer exerts any spring force on the lever spring 18 . As a result, the servo spring 26 is limited axially and rattling of the servo spring 26 when disengaging is avoided. In particular, the lever spring 18 is centered on the standoff 42 . This embodiment is essentially space-neutral, has a small number of components and only slight deflection of the lever spring 18 at the point of application of the servo spring 26. Furthermore, the retaining hooks 28 allow easy assembly.

At the in 3 The embodiment shown is compared to that in 2 illustrated embodiment of the support stop 34 radially outward from the web 32 of the retaining hook 28 from. The web 32 thereby forms a stop for the defined positioning of the lever spring 18 in the radial direction and/or for centering. In particular, it is possible with a friction clutch 10, for example, alternating both the in 2 shown retaining hooks 28 as well as in 3 provided holding hook 28 shown. This embodiment is essentially space-neutral, has a small number of components and only slight deflection of the lever spring 18 at the point of application of the servo spring 26. Furthermore, the retaining hooks 28 allow easy assembly.

At the in 4 embodiment shown is compared to the in 2 illustrated embodiment, the second force edge 40 of the servo spring 26 resting on the lever spring 18 is provided on a smaller radius than the first force edge 38 of the servo spring 26 resting on the holding hook 28 . In addition, the spacer bolt 42 is not embodied as a separate component riveted to the clutch cover 12 but as a one-piece component with the clutch cover and a component bent off the clutch cover 12 . This embodiment is essentially space-neutral, has a small number of components and, due to the long lever arm, lower servo spring forces of the servo spring 26, which can also result in lower tolerance requirements. Furthermore, the retaining hooks 28 allow easy assembly.

At the in 5 embodiment shown is compared to the in 3 illustrated embodiment, the second force edge 40 of the servo spring 26 resting on the lever spring 18 is provided on a smaller radius than the first force edge 38 of the servo spring 26 resting on the holding hook 28 . For this purpose, the support stop 34 does not protrude radially outward, but radially inward from the web 32 . In addition, the spacer bolt 42 is not embodied as a separate component riveted to the clutch cover 12 but as a one-piece component with the clutch cover and a component bent off the clutch cover 12 . This embodiment is essentially space-neutral, has a small number of components and, due to the long lever arm, lower servo spring forces of the servo spring 26, which can also result in lower tolerance requirements. Furthermore, the retaining hooks 28 allow easy assembly.

At the in 6 In the illustrated embodiment, in comparison to the previous embodiments, the servo spring 26 is provided outside the clutch cover 12 and is supported indirectly on the lever spring 18 via a retaining hook 28 that is axially movable relative to the clutch cover 12 . The support stop 34 of the holding hook 28 is also provided outside of the clutch cover 12 . At the end of the web 32 pointing away from the support stop 34 there is a thickening 44 which can strike the lever spring 18 in order to impress the applied spring force of the servo spring 26 on the lever spring 18 . Furthermore, the thickening 44 has a limit stop 46 pointing towards the pressure plate 14 and which can strike the pressure plate 14 when the pressure plate 14 is in a corresponding position. In particular, a plurality of, for example at least three, correspondingly designed holding hooks 28 are distributed uniformly relative to one another in the circumferential direction on a common radius.

At the in 7 embodiment shown is compared to the in 6 In the illustrated embodiment, the retaining hook 26 does not strike the pressure plate 14, but rather a spacer bolt 42, the spacer bolt 42 being made in one piece with the clutch cover in the illustrated embodiment. Additionally or alternatively, a spacer bolt 42 designed as a separate component can be provided, which can be connected to the clutch cover 12 by riveting, for example. Furthermore, the wire ring 22 is replaced by a pronounced lug 48, replacing the wire ring 22 with the lug 48 or replacing the lug 48 with the wire ring 22 is possible in principle in all of the illustrated embodiments. When the friction clutch 10 wears out, the lever spring 18 pulls the retaining hook 28 in the direction of the pressure plate 14 and thereby tensions the servo spring 26. When disengaging, the retaining hook 28 is again supported on the spacer bolt 42 on the clutch cover 12.

At the in 8th embodiment shown is compared to the in 7 illustrated embodiment, the servo spring 26 is designed in one piece with the lever spring 18 in that the servo spring 26 is designed as a radially outwardly protruding spring tongue connected to the lever spring 18 on the inside. Furthermore, the retaining hook 28 is designed in one piece with the clutch cover 12 . As a result, a particularly small number of components is achieved. The characteristic curve achievable by such an integral combination of the servo spring 26 with the lever spring 18 can be essentially linear. This means that initially the desired compensating effect of the servo spring 26 can be achieved. After reaching the maximum, however, the lever spring force decreases again, while the servo spring force continues to increase. As a result, the wear area is shortened.

At the in 9 illustrated embodiment protrudes compared to the in 3 illustrated embodiment of the retaining hook 28 significantly further into the friction clutch 10 inside. This makes it possible for the servo spring 26 to act on the lever spring 18 not directly but only indirectly via the pressure plate 14 . For this purpose, the pressure plate 14 has a projection 50 protruding radially inwards, on which the second force edge 40 of the servo spring 26 can rest. Alternatively, it can be provided that the holding hook 28 surrounds the pressure plate 14 radially on the outside in order to position the servo spring 26 between the support stop 34 of the holding hook 28 and the pressure plate 14 . In a further embodiment, the retaining hook 28 can also encompass the lever spring 18 radially on the outside without being guided through a spring opening provided in the lever spring 18 .

At the in 10 embodiment shown is compared to the in 3 In the illustrated embodiment, the servo spring 26 is provided radially outward of the point of application of the lever spring on the cam 22 and also radially outward of the pivot point of the lever spring 18 on the lug 48 . This makes it possible to replace the retaining hook 28 with a tab 52 bent out of the axially running part of the clutch cover 12 . In the exemplary embodiment shown, the clutch cover 12 has a first holding surface 54 pointing toward the pressure plate 14 and the tab 50 has a second holding surface 56 pointing away from the pressure plate 14, between which the servo spring 26 is held captively, in particular with pretension. The servo spring 26 extends radially inwards from the region of the tab 52 to such an extent that the second force edge 40 of the servo spring 26 can act on the lever spring 18 . In the exemplary embodiment shown, the lever spring 18 has at least one extension piece 58 which protrudes radially outwards and on which the servo spring 26 rests.

As an alternative to the in 10 illustrated embodiment can be as in 11 shown, the servo spring 26 extend radially inwards to such an extent that the second force edge 40 of the servo spring 26 can act on the lever spring 18 between the pivot point of the lever spring 18 on the nose 48 and the point of application on the cam 22, so that the extension piece 58 is omitted can. Furthermore, it is possible that the first holding surface 54 pointing to the pressure plate 14 is provided by the tab 52 .

Reference List

10

friction clutch

12

clutch cover

14

pressure plate

16

spring tongue

18

lever spring

20

wire ring

22

cam

24

return spring

26

servo spring

28

retaining hook

30

spring opening

32

web

34

support stop

36

contact surface

38

first edge of power

40

second edge of power

42

standoffs

44

thickening

46

limit stop

48

Nose

50

Approach

52

tab

54

first holding surface

56

second holding surface

58

extension piece

Claims (13)

Friction clutch for coupling a drive shaft of a motor vehicle engine to a transmission input shaft of a motor vehicle drive, with a counter-plate for introducing a torque, a pressure plate (14) that can be displaced relative to the counter-plate for the frictional pressing of a clutch disc for dissipating the torque, a clutch cover (12) connected to the counter-plate for at least partially covering the pressure plate (14), a pivotable A lever spring (18), in particular a disk spring, supported on the clutch cover (12) for moving the pressure plate (14), a servo spring (26), in particular designed as a lever spring, for reducing an actuating force that can be applied by an actuating system and is required to move the pressure plate (14). in the event of wear and a support element (28), designed in particular as a retaining hook (28), spaced apart from the pressure plate (14) for axially supporting the servo spring (26), the support element (28) having a web (32) running in the axial direction and a has a support stop (34) protruding in the radial direction and/or essentially in the tangential direction for axial contact with a first force edge (38) of the servo spring (26), the lever spring (18) having a spring opening (30) and the web (32 ) of the support element (28) protrudes through the spring opening (30), characterized in that the servo spring (26) is designed in one piece with the lever spring (18), the servo spring (26) in particular as a spring tongue of the lever spring ( 18) is configured. friction clutch after claim 1 characterized in that at least one spacer bolt (42), preferably at least three spacer bolts (42), is connected to the clutch cover (12) for axial contact with a second force edge (40) of the servo spring that differs from the first force edge (38), the Spacer bolts (42) protrudes in particular through the lever spring (18). friction clutch after claim 1 or 2 characterized in that the support element (28) is designed in one piece with the clutch cover (12). friction clutch after claim 1 or 2 characterized in that the servo spring (26) is axially supported on an outside pointing away from the pressure plate (14) in the axial direction with a second force edge (40) different from the first force edge (38), the supporting element (28) being movable relative to the Clutch cover (12) is passed through the clutch cover (12). Friction clutch according to one of Claims 1 until 4 characterized in that in the closed state of the friction clutch (10) the lever spring (18) acts directly or indirectly on the clutch cover (12) over a first radius and acts directly or indirectly on the pressure plate (14) over a second radius, the support element ( 28) located radially inward of both the first radius and the second radius, or radially outward of both the first radius and the second radius. Friction clutch according to one of Claims 1 until 5 characterized in that the support stop (34) of the support element (28) is arranged in the axial direction at the level of the pressure plate (14), the servo spring (26) in particular having a second force edge (40) that is different from the first force edge (38). Servo spring (26) engages the pressure plate (14). Friction clutch according to one of Claims 1 until 6 characterized in that the supporting element (28) has a limit stop (42) pointing towards the pressure plate (14) for striking against the pressure plate (14) in an axial extreme position of the pressure plate (14). Friction clutch for coupling a drive shaft of a motor vehicle engine to a transmission input shaft of a motor vehicle transmission, with a counter-plate for introducing a torque, a pressure plate (14) which can be displaced relative to the counter-plate for frictionally pressing a clutch disc for dissipating the torque, a clutch cover (12) connected to the counter-plate for at least partial covering of the pressure plate (14), a lever spring (18) pivotably supported on the clutch cover (12), in particular a plate spring, for moving the pressure plate (14), and a servo spring (26), in particular designed as a lever spring, for reducing a Displacement of the pressure plate (14) required actuation force that can be applied by an actuation system in the event of wear, the clutch cover (12) having a first retaining surface (54) pointing towards the pressure plate (14) for contact with the servo spring (26) and one of the pressure plate (14) has a pioneering second holding surface (56) for contact with the servo spring (26), the servo spring (26) being secured axially between the first holding surface (54) and the second holding surface (56), characterized in that the lever spring (18) in closed state of the friction clutch (10) on a first radius directly or indirectly on the clutch cover (12) and acts directly or indirectly on the pressure plate (14) on a second radius, the first radius being larger than the second radius. friction clutch after claim 8 characterized in that the clutch cover (12) and/or the servo spring (26) has at least one assembly window for axial insertion past the first retaining surface (54) and/or the second retaining surface (56) of the clutch cover (12), the servo spring (26) for positioning the servo spring (26) between the first holding surface (54) and the second holding surface (56) relative to the clutch cover (12) can be rotated in the circumferential direction. friction clutch after claim 8 or 9 characterized in that the first holding surface (54) and/or the second holding surface (56) is formed by a tab (52) bent out of the material of the clutch cover. Friction clutch according to one of Claims 8 until 10 characterized in that the lever spring (18) in the closed state of the friction clutch (10) acts directly or indirectly on a first radius on the clutch cover (12) and on a second radius directly or indirectly on the pressure plate (14), the servo spring ( 26) engages the lever spring (18) radially outward of both the first radius and the second radius or between the first radius and the second radius. Friction clutch according to one of Claims 1 until 11 characterized in that the lever spring (18) in the closed state of the friction clutch (18) acts directly or indirectly on a first radius R ₁ on the clutch cover (12) and on a second radius R ₂ acts directly or indirectly on the pressure plate (14), wherein the servo spring (36) acts directly or indirectly on the lever spring (18) on a third radius R ₃ , where 0.00≦|R ₂ -R ₃ |/R ₂ ≦0.30, in particular 0.01≦|R ₂ -R ₃ |/R ₂ ≤ 0.25, preferably 0.05 ≤ |R ₂ -R ₃ |/R ₂ ≤ 0.15 and more preferably 0.07 ≤ |R ₂ -R ₃ |/R ₂ ≤ 0.10 applies. Friction clutch according to one of Claims 1 until 12 characterized in that the servo spring (26) acts on an axial side of the lever spring (18) pointing towards the pressure plate (14) or on an axial side of the lever spring (18) pointing away from the pressure plate (14).

Images