EP2861883A1

EP2861883A1 - Friction clutch

Info

Publication number: EP2861883A1
Application number: EP13727094.8A
Authority: EP
Inventors: Christophe Reichert
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2012-06-14
Filing date: 2013-05-29
Publication date: 2015-04-22
Also published as: DE112013002928A5; CN104379955A; WO2013186046A1; DE102013209993A1; CN104379955B

Abstract

According to the invention, a friction clutch for coupling a drive shaft of a motor vehicle engine to a gearbox input shaft of a motor vehicle gearbox is provided with: a counter-plate (12) for introducing a torque; a pressing plate (14) displaceable relative to the counter-plate for frictionally engaged pressing of a clutch disc in order to output the torque; a clutch cover connected to the counter-plate for at least partially covering the pressing plate; a lever spring (24), particularly a disc spring, supported pivotably on the clutch cover (20) in order to displace the pressing plate; and a servo spring (32), designed particularly as a lever spring, for reducing an actuating force necessary for displacing the pressing plate in the event of wear, which force is to be applied by an actuating system, wherein the servo spring is supported at a first force edge (36) on the clutch cover and at a second force edge (38) on the lever spring. Because the servo spring can be supported on the clutch cover and the lever spring, it is not necessary to provide a bolt screwed to the pressing plate. The friction clutch can therefore be produced with a lower construction expense.

Description

friction clutch

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.

From DE 10 2006 058 31 1 A1 a friction clutch is known which is one of a

Has lever spring axially displaceable pressure plate for frictional pressing a clutch disc between the pressure plate and a counter-plate. With the counter plate a clutch cover is firmly connected, through which a bolt screwed to the pressure plate screw is passed. At the side facing away from the pressure plate side of the clutch cover, the screw on a screw head, which is supported on a disposed between the clutch cover and the screw head cup spring to the clutch cover. By the clutch cover and the screw contacting disc spring required for actuating the friction clutch actuating force can be influenced in a wear of the clutch disc.

There is a constant need for the design effort to produce a

Reduce friction clutch.

It is the object of the invention to show measures that one with low

allow constructive effort producible friction clutch.

The object is achieved by a friction clutch with the features of claim 1. Preferred embodiments of the invention are specified in the subclaims, which individually or in combination may constitute an aspect of the invention.

According to the invention, a friction clutch for coupling a drive shaft of a

Motor vehicle engine with a transmission input shaft of a motor vehicle transmission provided with a counter-plate for introducing a torque, a relative to the counter-plate displaceable pressure plate for frictionally pressing a clutch disc for discharging the torque, a connected to the counter-plate clutch cover for at least partially covering the pressure plate, a pivotally supported on the clutch cover lever spring, in particular plate spring, for displacing the pressure plate and a, in particular designed as a lever spring servo spring to reduce a force required for displacing the pressure plate by an actuating system applied operating force during wear, wherein the servo spring is supported on a first force edge on the clutch cover and on a second edge of force on the lever spring.

Since the servo spring can be supported on the clutch cover and the lever spring, it is particularly not necessary to provide a bolt bolted to the pressure plate, so that the friction clutch can be manufactured with a low design effort, with an increase in an operating force at wear by the servo spring at least partially compensated. In particular, it is possible to reduce the number of components and / or to save machining operations, in particular production of an internal thread in the pressure plate. Furthermore, the servo spring can act substantially directly on the lever spring, so that between the servo spring and the lever spring provided intermediate components can be saved in the power flow. This avoids that intermediate components due to their own elastic behavior under the influence of force can affect the spring effect applied by the servo spring on the lever spring. For example, it is not necessary that the servo spring exerts a spring force on the pressure plate, so that the pressure plate can pass this spring force to reduce the operating force in the wear area to the lever spring. Instead, the power flow between the servo spring and the lever spring can be guided past the pressure plate, so that there is a cost-effective and space-saving design for the friction clutch. In particular, with the aid of the servo spring, the maximum operating force to be provided for actuating the friction clutch can be reduced so that an actuating system for generating the actuating force can be dimensioned to be smaller and less bulky. It is possible that the smaller space requirement for the actuating system does not lead to an increased space requirement for the remaining friction clutch. In particular, the servo spring is designed such that the servo spring builds up an increasingly strong spring force with an increasingly strong wear of friction linings in the unactuated state of the friction clutch, which points in the direction of the actuating force. If, during an actuation of the friction clutch, the lever spring sweeps over an increasingly larger pivoting path with ever increasing wear on the clutch disc, a part of the force required to displace the pressure plate over an ever increasing stroke can be provided by the servo spring be, so that in particular an increase in the actuation force, for example by setting up the lever spring designed as a plate spring, can be compensated.

The servo spring can be configured in particular as a plate spring. The servo spring can be designed for this purpose, for example, as a circumferential conical ring. Preferably, the servo spring has radially outwardly and / or radially inwardly projecting lugs, which form the first force edge or the second force edge. For this purpose, the servo spring can, for example, have a circumferential, conical annular disk spring area, which in particular provides a large part of the spring action of the servo spring. By protruding approaches the servo spring, for example, can be inserted against rotation in corresponding recesses of the pressure plate to facilitate the assembly of the friction clutch. Furthermore, the lever spring can in particular have radially inwardly projecting spring tongues, which preferably protrude from a circumferential ring, wherein the servo spring can be supported with the protruding lugs on the spring tongues of the lever spring. Through the approaches, the radial position of the respective force margin can be easily adjusted. Further, by the dimensioning, in particular the radial extent, the respective lugs and / or a circumferentially closed ring, the spring properties of the servo spring can be adjusted by low design and manufacturing effort.

The counterplate of the friction clutch can be configured, in particular, by a flywheel, which can be non-rotatably connected to, for example, a crankshaft of an automobile engine. In particular, it is possible to use the friction clutch for a double clutch, wherein the counter-plate can be formed in particular by a common central plate of the double clutch, so that this central plate can form a counter-plate on both axial sides for a respective friction clutch. The clutch cover is preferably fixedly connected to the counter-plate, for example by screwing or riveting. In particular, the coupling disc provided in the axial direction between the pressure plate and the counterplate can be non-rotatably connected to the transmission input shaft, for example via spline teeth. The clutch disc may in particular have friction linings which wear over their service life and can thereby become thinner. Preferably, the clutch disc has a lining suspension for the friction linings, which allow a smooth closing of the friction clutch and in particular provide a spring force for opening the friction clutch in the closed state of the friction clutch. Particularly preferred is a return spring connected to the pressure plate and the clutch cover or the counter plate for positioning the attachment. press plate in an open position, when no pressure is applied to the pressure plate of the lever spring provided. If the friction clutch is "normally closed" in an actuating force not applied to the lever spring by an actuating system, the pressure spring may follow the lever spring by the return spring when the lever spring is in position by an actuating force applied to the lever spring by the actuating system The return spring is particularly preferably fastened to the pressure plate by means of a spacer bolt fixedly connected to the pressure plate, for example by plastic deformation, for example by a corresponding opening in the clutch cover through the clutch cover be guided to the outside, so that a projecting from the bolt stop can strike on reaching the clutch of a predetermined maximum wear at the wear area end of the friction linings Tandbolzen a transport lock are formed, which can prevent unintentional relative movement of the pressure plate to the counter plate before mounting the friction clutch in a drive train of a motor vehicle. The lever spring can in particular be pivoted about a ring-shaped pivot point, wherein the annular circumferential pivot point is preferably defined by at least one supported on the clutch cover wire ring.

In particular, it is provided that the first force edge contacts the clutch cover and / or the second force edge the lever spring. Due to the direct contact of the servo spring with the clutch cover and / or with the lever spring intermediate components can be saved, so that a small number of components and a simple construction of the friction clutch is made possible.

Preferably, the force applied to displace the pressure plate on the lever spring actuation force away from the counter-plate, wherein the friction clutch is closed at a missing actuation force for torque transmission to the clutch disc. The friction clutch can be designed as a drawn normally closed friction clutch. This makes it possible in particular to provide the pivot point for the lever spring radially outward to a contact point of the lever spring on the pressure plate. The servo spring can thereby be particularly easily attacked without additional significant space requirements significantly spaced from the pivot point of the lever spring on the lever spring, so that there is a correspondingly large spring travel for the servo spring by the lever effect of the lever spring. In particular, it is possible by the between the pivot point of the lever spring and the support point of the second force edge of the servo spring on the lever spring trained lever arm and a suitably selected spring characteristic of the servo spring particularly easy to set a suitable spring force curve of the servo spring on the lever spring over a defined wear range.

Particularly preferably, the first force edge of the servo spring is arranged radially outside the second force edge of the servo spring. The servo spring can thereby be supported radially on the outside of the clutch cover and radially inward on the lever spring. This makes it easier to design the servo spring, in particular in a drawn normally closed friction clutch, as a compression spring, which can be designed in particular as a space-saving plate spring.

In a preferred embodiment, the first force edge of the servo spring is located on an inner side of the clutch cover and the second force edge of the servo spring is located on a pressure plate side of the lever spring facing the pressure plate. The servo spring can thereby be positioned substantially completely within the friction clutch, so that no additional space for the friction clutch is required. The servo spring can be supported on a provided between the lever spring and the pressure plate and / or counter plate part of the clutch cover. The servo spring may be completely provided within a space bounded by the clutch cover and the counter plate. The inside of the clutch cover points to a limited by the clutch cover and the counter plate space in which the pressure plate is provided.

In particular, the clutch cover has a retaining hook pointing to the pressure plate, wherein the retaining hook forms an inside of the clutch cover facing away from the pressure plate and the first force edge of the servo spring bears against the inside of the clutch cover formed by the retaining hook. The retaining hook can in particular extend radially outward to the lever spring, so that the retaining hook and the lever spring can not interfere with each other. Preferably, the retaining hook may have a radially inwardly pointing approach, which forms the region of the inside of the clutch cover, in which the servo spring is supported on the clutch cover. In particular, it is possible for the attachment to protrude at least partially into a radial region which can be covered by the lever spring. That is, viewed in the axial direction, the lever spring can cover the approach of the holding hook. In this case, the lever spring in particular recesses in order to pass the retaining hooks through the lever spring can. Particularly preferably, the lever spring after passing the holding hook in the circumferential direction be twisted so that at the same time a captive for the lever spring in the clutch cover is formed by the retaining hook. Additionally or alternatively, the retaining hook can be used as a stop for a maximum permissible pivot position of the lever spring.

The servo spring is preferably arranged completely in a radial region which can be covered by the pressure plate. The radially inner and radially outer boundary of the radial region can be defined by the first force edge and the second force edge. Viewed in the axial direction, the pressure plate can completely cover the servo spring. The radial space requirement of the friction clutch is thus not determined by the servo spring, so that no additional radial space is required for the servo spring.

Particularly preferably, the pressure plate has at least one cam for engagement with the lever spring on a contact radius, wherein the second force edge of the servo spring contacts the lever spring substantially on the contact radius. As a result, both the force flow between the lever spring and the pressure plate and the power flow between the lever spring and the servo spring can take place on a substantially common radius. This leads to comparable loads on the lever spring when closing and when opening the friction clutch. In particular, it is possible that a part of the servo spring, which forms the second force edge, is arranged between two cams or a cam between two parts of the servo spring which form the second force edge, so that an anti-twist arrangement results which prevents a relative rotation of the servo spring to the pressure plate or at least limited.

In a preferred embodiment it is provided that the first force edge of the

Servo spring rests on an outer side of the clutch cover and the second force edge of the servo spring is supported on a pressure plate facing the pressure plate side of the lever spring. The servo spring, for example, engage around the clutch cover and the lever spring like a clamp. For this purpose, the servo spring can be guided through openings provided in the clutch cover and the lever spring. This makes it possible for the first force edge and the second force edge to be positioned radially outwardly to a connecting piece guided through the clutch cover and the lever spring, which connects the first force edge and the second force edge to one another. For this purpose, for example, a plurality of only partially extending in the circumferential direction servo springs may be provided, which can be inserted radially inward into corresponding openings and moved radially outward to clasp the clutch cover and the lever spring.

In particular, the servo spring has a guided through openings in the clutch cover and the lever spring spring hook for supporting the servo spring on the lever spring, wherein in particular the spring hook via a support element, in particular a wire ring, is supported on the lever spring. The servo spring can be designed as a ring closed in the circumferential direction, so that in particular only exactly one servo spring is sufficient. By the support member, the servo spring can be supported on the facing in the mounting direction to the pressure plate back of the lever spring. The spring hook can be clipped for this purpose in particular with a closed wire ring. The servo spring may, in particular, have a cup spring region which is conical in the manner of a cup spring. The spring hooks can protrude substantially in the axial direction of the disc spring area. The disc spring area can thereby be provided substantially completely on the outside of the clutch cover. A kinematically inverted design is also possible, in which the cup spring region is provided with the second force edge substantially completely on the pressure plate side of the lever spring and the spring hook is supported with the first force edge, in particular by means of a support member on the clutch cover.

The invention further relates to a clutch assembly for coupling a drive shaft of an automotive engine having at least one transmission input shaft of a motor vehicle transmission with at least one friction clutch, which may be off and on as described above and an actuating system for actuating the at least one friction clutch. The clutch unit is in particular as a double clutch with two friction clutches for coupling the drive shaft with a first transmission input shaft and / or a second transmission input shaft, wherein preferably the counter plates for both friction clutches are formed by a common central plate. Since the servo spring of the friction clutch can be supported on the clutch cover and the lever spring, it is particularly not necessary to provide a bolt bolted to the pressure plate, so that the friction clutch can be made with a low design effort, with an increase in an operating force at wear at the same time the servo spring can be at least partially compensated. The invention will now be described by way of example with reference to the accompanying drawings with reference to preferred embodiments, wherein the features shown below, both individually and in combination may represent an aspect of the invention. Show it:

1 is a schematic sectional view of a friction clutch in a first embodiment,

2 is a schematic exploded perspective view of the friction clutch of FIG. 1,

3 shows a schematic sectional view of a friction clutch in a second

embodiment,

4 is a schematic exploded perspective view of the friction clutch of Fig. 3 and

5: a qualitative comparison of a course of an actuating force for the friction clutches from FIG. 1 and FIG. 2 with and without servo spring.

The friction clutch 10 shown in FIG. 1 has a counter-plate 12 and a pressure plate 14 which is displaceable relative to the counter-plate 12 in order to be able to press a friction plate 16 containing friction plate 16 frictionally to close the friction clutch 10. With the counter-plate 12, a clutch cover 20 is screwed to which an annular ring pivot forming a ring 22 designed as a slotted plate spring lever spring 24 is pivotally supported for displacing the pressure plate 14. For this purpose, the lever spring 24 abut a protruding cam 36 of the pressure plate 14. Connected to the clutch cover 20 and the pressure plate 14 is a return spring 28 designed as a leaf spring, which moves the pressure plate 14 away from the counter plate 12 when substantially no axial force acts on the pressure plate 14. The lever spring 24 may be inserted between the clutch cover 20 and the pressure plate 14 such that the lever spring 24 in the unactuated state, that is, when substantially no actuating force 30 is applied to the lever spring 24, the pressure plate 14 presses against the counter plate 12 and thereby the Friction clutch in the unactuated state closes. When the actuating force 30 directed away from the counter-plate 12 acts radially inward on the lever spring 24 and the Lever spring 24 moves away from the counter-plate 12, the lever spring 24 can pivot away from the counter-plate 12, wherein by the restoring force applied by the return spring 28, the pressure plate 14 of the lever spring 24 can follow to open the friction clutch 10 in the actuated state.

With wear of the friction clutch 10, the friction linings 16 of the clutch disc 18 become thinner, so that the actuating travel of the lever spring 24 between the closed and the open position becomes greater and / or the actuation force 30 required for pivoting the lever spring 24 increases. In order to compensate for at least a portion of the increasing actuating force 30 in the event of wear, a servo spring 32 designed essentially as a plate spring is provided. In the illustrated embodiment, the clutch cover 20 has a retaining hook 34, so that the servo spring 32 is supported with a radially outer first force edge 36 on the retaining hook. With a radially inner second force edge 38, the servo spring 32 is radially spaced from the ring 22 supported on a pressure plate 14 facing the pressure plate side 40 of the lever spring 24. In a wear of the friction linings 16, the lever spring 24 is pivoted with the friction clutch 10 in a position in which the servo spring 32 has set up stronger and applies a spring force in the direction of the actuating force 30 on the lever spring 24, so that a correspondingly lower actuation force 30 for Opening the friction clutch 10 is required.

In the illustrated embodiment, the servo spring 32 is disposed entirely within a bounded by the counter-plate 12 and the clutch cover 20 space. The servo spring 32 rests with its first force edge 36 on an inner side 42 of the clutch cover 20, wherein the servo spring 32 is supported by the retaining hook 34 in a region of the inner side 42 facing away from the counter-plate 12. As shown in Fig. 2, the servo spring 32 may have a plurality of radially projecting lugs 44, through which the first force edge 36 and the second force edge 38 can be formed. As a result, for example, the lugs 44 forming the second force edge 38 can be provided on a comparable radius as the cams 26 of the pressure plate 14, in order to form an anti-twist device.

In the embodiment of the friction clutch 10 shown in FIG. 3 and FIG. 4, the servo spring 32 is not on the inside 42 but on an outside 46 of the coupling in comparison to the embodiment of the friction clutch 10 shown in FIGS. 1 and 2. Lungsdeckels 20 supported. The servo spring 32 has a guided through the clutch cover 20 and the lever spring 24 spring arm 48 which is connected to a wire ring 50, for example by clipping, to be supported on the Anpressplattenseite 40 of the lever spring 24. A formed by the clutch cover 20 holding hook 34 is not required in this case.

In Fig. 5, a force 52 in N via an actuating travel 54 in mm is shown when the lever spring 24 is pulled to open the friction clutch 10. An actuating force 56 without Servofeder 32 has in comparison to the actuating force 30 with servo spring 32 to a difference 58 higher maximum required actuating force 56, on the basis of an actuating system for actuating the friction clutch 10 must be dimensioned. By the servo spring 32, a lower maximum required actuation force 30 can result, which makes the operation of the friction clutch more comfortable and allows, for example, a smaller dimensioned actuation system.

Reference numeral friction clutch

counterplate

pressure plate

friction lining

clutch disc

clutch cover

ring

lever spring

cam

Return spring

operating force

servo spring

retaining hook

first force border

second force border

Anpressplattenseite

inside

approach

outside

spring arm

wire ring

force

actuating

Operating force without servo spring

difference

Claims

claims

1 . Friction clutch for coupling a drive shaft of an automotive engine with a transmission input shaft of a motor vehicle transmission, with

a counter-plate (12) for introducing a torque,

a pressure plate (14) displaceable relative to the counterplate (12) for the frictional pressing of a clutch disc (18) for discharging the torque, a clutch cover (20) connected to the counterplate (12) for at least partially covering the pressure plate (14),

a pivotally mounted on the clutch cover (20) lever spring (24), in particular disc spring, for displacing the pressure plate (14) and

a servo spring (32), in particular designed as a lever spring, for reducing an actuation force (30) which can be applied by an actuation system for displacing the pressure plate (14) during wear,

wherein the servo spring (32) is supported at a first force edge (36) on the clutch cover (20) and on a second force edge (38) on the lever spring (24).

2. Friction clutch according to claim 1, characterized in that the first force edge (36) the clutch cover (20) and / or the second force edge (38) contacts the lever spring (24).

3. Friction clutch according to claim 1 or 2, characterized in that for displacing the pressure plate (14) on the lever spring (24) attachable actuating force (30) of the counter-plate (12) points away, wherein the friction clutch (10) at a lack of actuation force (30) is closed.

4. Friction clutch according to one of claims 1 to 3, characterized in that the first force edge (36) of the servo spring (32) is arranged radially outward to the second force edge (38) of the servo spring (32).

5. Friction clutch according to one of claims 1 to 4, characterized in that the first force edge (36) of the servo spring (32) on an inner side (42) of the coupling Cover (20) and the second force edge (38) of the servo spring (32) on a pressure plate (14) facing the pressure plate side (40) of the lever spring (24).

6. Friction clutch according to claim 5, characterized in that the clutch cover (20) has a pressure plate (14) facing retaining hooks (34), wherein the retaining hook (34) one of the pressure plate (14) pioneering inside (40) of the clutch cover (20 ) and the first force edge (36) of the servo spring (32) bears against the inside (42) of the clutch cover (20) formed by the retaining hook (34).

7. friction clutch according to claim 5 or 6, characterized in that the servo spring (32) is arranged completely in one of the pressure plate (14) coverable radial region.

8. Friction clutch according to one of claims 5 to 7, characterized in that the pressure plate (14) has at least one cam (26) for engagement with the lever spring (24) at a contact radius, wherein the second force edge (38) of the servo spring (32). contacted the lever spring (24) substantially at the contact radius.

9. friction clutch according to one of claims 1 to 4, characterized in that the first force edge (36) of the servo spring (32) on an outer side (46) of the clutch cover (20) abuts and the second force edge (38) of the servo spring (32) one to the pressure plate (14) facing pressure plate side (40) of the lever spring (24) is supported

10. Friction clutch according to claim 9, characterized in that the servo spring

(32) has a through spring through openings in the clutch cover (20) and the lever spring (24) guided spring hook (48) for supporting the servo spring (32) on the lever spring (24), wherein in particular the spring hook (48) via a supporting element, in particular a wire ring (50) is supported on the lever spring (24).