DE102015225636A1 - Lever spring for shifting a pressure plate of a friction clutch - Google Patents

Abstract

It is a lever spring (10) for displacing a pressure plate (42, 44) of a friction clutch (28, 30) provided with a radially extending spring tongue (14) for receiving an actuating force at a radially inner force introduction region (16) and at a radially outer End with the spring tongue (14) connected separate force edge (12) for transmitting the actuating force to the pressure plate (42, 44), wherein in the radial direction between the force introduction region (16) and the radially outer edge of the force edge (12) has a pivot surface for training a distance (d) of a center of mass (22) of the spring tongue (14) and of the radial extension of the spring tongue (14) provided proportion of the force edge (12) to the pivot surface is lower than in one with the force edge (12) integrally designed spring tongue (14). By shifting the center of mass (22) closer to the pivot point (20), the influence of centrifugal force on the required actuating force can at least be reduced, so that essentially identical actuating force profiles are possible in all operating states of a friction clutch (28, 30).

Description

The invention relates to a lever spring, by means of which a pressure plate of a friction clutch can be displaced by pivoting in response to an actuating force acting on the lever spring in order to press a clutch disc.

Out DE 10 2012 221 068 A1 is a lid assembly for a friction clutch is known in which an actuating element in the form of a designed as a plate spring with spring tongues lever spring in the axial direction immovable but pivotally received in a clutch cover. At an radially inner end of the spring tongues, an actuating force can be introduced, whereby the plate spring is pivoted and a pressure plate for frictional pressing a clutch disc between the pressure plate and a counter plate can be moved to open the clutch.

There is a constant need in all operating conditions of a friction clutch to provide substantially similar Betätigungskraftverläufe.

It is the object of the invention to show measures that allow substantially similar Betätigungskraftverläufe in all operating conditions of a friction clutch.

The object is achieved according to the invention by a lever spring having the features of claim 1. Preferred embodiments of the invention are specified in the subclaims and the following description, which individually or in combination may represent an aspect of the invention.

According to the invention, a lever spring for displacing a pressure plate of a friction clutch is provided with a radially extending spring tongue for receiving an actuating force at a radially inner force introduction region and at a radially outer end connected to the spring tongue separate force edge for transmitting the actuating force to the pressure plate, wherein in the radial direction between the force introduction region and the radially outer edge of the force edge a pivot surface for forming a, in particular circumferential circumferential pivot point is provided for pivoting the lever spring, wherein a distance of a center of mass of the spring tongue and provided in the radial extension of the spring tongue portion of the force edge to the pivot surface less is as a one-piece executed with the force of force spring tongue.

Due to the fact that the lever spring was not punched in one piece from a metal sheet and bent in the manner of a plate spring, but the force edge on the one hand and the spring tongue on the other hand are made as separate components, it is possible to form the mass distribution of the lever spring in the radial direction deviating from a one-piece mass continuum , This makes it possible in particular to provide more mass or a higher density in the force edge. As a result, in comparison to a one-piece lever spring, the center of gravity moves in a peripheral region of the respective spring tongue closer to the pivot point defined by the pivot surface. Here, the knowledge is exploited that attack at the center of gravity during operation of the friction clutch centrifugal forces that can act through the center between the center of gravity and the pivot point formed lever arm by the pivoted position of the lever spring with a share of force in the axial direction of the pressure plate. In this case, the centrifugal force pointing in the radial direction can be divided into a portion along the pivoted longitudinal direction of the lever spring and a portion in the axial direction. This means that depending on the current speed of the friction clutch, the centrifugal force and the centrifugal force caused by the force acting on the pressure plate changes, which would result in different speeds to be provided by the actuating system actuating forces for different speeds. As a result, for example, the operation of a clutch pedal by a driver of a motor vehicle would feel different depending on the current engine speed, which can be irritating and uncomfortable for the driver. Furthermore, in an automatic transmission a certain coupling position is correlated with a specific actuating force, so that in particular the automatic fast or slow control of certain coupling positions is disturbed by a coupling control software provided for this purpose, in particular when closing the friction clutch. This can, for example, lead to a sudden, jerky closing of the friction clutch or a clearly too slow closing of the friction clutch, which is perceived as uncomfortable for the driver. By shifting the center of gravity closer to the pivot point, however, the influence of centrifugal force on the required actuating force can at least be reduced, so that substantially similar actuation force profiles are made possible in all operating states of a friction clutch.

The lever spring may in particular be designed in the manner of a plate spring, in which a plurality of circumferentially preferably uniformly distributed spring tongues can protrude radially inward from the force edge. In particular, an in Circumferentially formed annular annular disk spring area, which may optionally be wholly or partially formed by the force edge. The cup spring region may allow pivoting of the lever spring by changing its taper about a circumferential pivot point. The force introduction regions formed at the radially inner end of the spring tongues can receive an actuating force provided by a hydraulic actuating system in particular. For this purpose, for example, be extended or retracted by the actuating system, a piston which presses or pulls against the force application areas, whereby the lever spring can be pivoted. The force edge can directly or indirectly, for example via an adjusting device for adjusting a wear-related misalignment of the pressure plate to a counter-plate of the friction clutch, engage the pressure plate and press the pressure plate on the counter plate to the closed position of the friction clutch or pivoting of the lever spring on pivoting of the lever spring Pull the counter plate into the open position of the friction clutch. By way of the distance of the force introduction region from the pivot point on the one hand and the distance of a contact region of the force edge from the pressure plate to the pivot point on the other hand, a suitable lever transmission can be set. The pivot surface may be supported directly or indirectly, for example via an adjusting device for adjusting a wear-related incorrect spacing of the pressure plate to a counter-plate of the friction clutch, pivotally supported on a part of the friction clutch, in particular a clutch cover. The pivot surface can act as an abutment for a pivot bearing. The pivot point for the lever spring is thereby formed on the surface of the lever spring in the pivot surface.

In a preferred embodiment, the force edge in the axial direction is substantially completely covered by the spring tongue in the circumferential angular range covered by the spring tongue. The force edge and the spring tongue can be arranged one behind the other in the axial direction. In particular, the force edge and the spring tongue have the same outer radius. The force edge can be stiffened by means of the spring tongue. In particular, this means that a particularly large amount of mass is positioned radially on the outside, as a result of which the center of gravity can be displaced to the pivot point.

In particular, the force edge has a higher density than the spring tongue. Preferably, the spring tongue is configured less massive than the force edge. For example, the spring tongue recesses and / or cavities. In particular, the force edge is designed in the circumferential direction as a continuous continuum, that is, the force edge has substantially no unfilled through holes or cavities. As a result of the higher density of the force edge, the center of mass of gravity, which is usually located in the radial direction within the pivot point, can be displaced closer to the pivot point.

Preferably, the force is made of a different material than the spring tongue. Due to the multi-part design of the lever spring, it is particularly easy to shift the center of mass to the pivot point by a material with a high density, such as steel, and the spring tongue a material with a low density, such as aluminum, is used for the force edge.

Particularly preferably, the force edge has a greater material thickness in the axial direction than the spring tongue. As a result, more mass can be positioned in the radially outer region of the lever spring through the thicker force edge, as a result of which the center of gravity can move closer to the pivot point radially outward.

In particular, an additional mass with the force edge and / or is connected to the lever spring radially outward to the pivot surface. As a result, more mass can be positioned in the radially outer region of the lever spring with the aid of the additional mass provided in addition to the force edge, as a result of which the center of gravity can move closer to the pivot point radially outward. In particular, a plurality of additional masses are provided, which may be spaced apart in the circumferential direction. In particular, in the intermediate regions between the additional masses, the force edge can act on a cam of the pressure plate, without the contact of the force edge being adversely affected by the additional masses. The additional masses can be provided in a free space between the cams, so that the axial space requirement does not increase by the additional masses, but can remain low.

Preferably, the distance d of the center of gravity to the pivot surface with respect to the outer radius R of the force edge is 0.0 ≦ d / R ≦ 0.5, in particular 0.0 ≦ d / R ≦ 0.33, preferably 0.0 ≦ d / R ≦ 0.2 and more preferably 0.0 ≤ d / R ≤ 0.1. This can already be achieved in comparison to a one-piece lever spring a significant reduction of the distance d and the influence of centrifugal force. Preferably, the center of gravity coincides substantially with the pivot point.

Particularly preferably, the force edge is positively connected via a separate fastening means, in particular riveted, with the spring tongue connected. The fastening means on the one hand provides a secure attachment of the force edge with the spring tongue and on the other hand provides a further mass that can be provided radially outward to the pivot point. By providing the fastening means, a displacement of the center of mass can already be achieved closer to the pivot point.

The invention further relates to a cover assembly for a friction clutch for coupling a drive shaft of a motor vehicle engine with at least one transmission input shaft of a motor vehicle transmission with a pressure plate for frictionally pressing a clutch disc between the pressure plate and a counter plate, a couplable with the drive shaft clutch cover and a directly or indirectly on the clutch cover pivotally supported lever spring, which may be formed and further developed as described above, for the axial displacement of the pressure plate in response to an initiation of an actuating system in the lever spring actuation force. By shifting the center of mass of the lever spring closer to the pivot point, the influence of centrifugal force on the required actuating force can at least be reduced, so that essentially identical actuating force profiles are made possible in all operating states of a friction clutch.

In particular, the lever spring in the manner of a plate spring by a change in its conicity is pivotable about a pivot point extending in the circumferential direction. The lever spring can thereby be made comparatively stiff, so that the pressure plate can be easily displaced, without much of the engagement of engaging the force application area actuating system for elastic bending of the spring tongues must be spent.

The invention further relates to a friction clutch for coupling a drive shaft of a motor vehicle engine with at least one transmission input shaft of a motor vehicle transmission with a counterpart plate coupled to the drive shaft for introducing a torque, a couplable with the transmission input shaft clutch disc and a cover assembly, which may be as described above and further developed , for frictionally pressing the clutch disc. By shifting the center of gravity of the lever spring of the cover assembly closer to the pivot point of the centrifugal force influence can be at least reduced to the required operating force, so that substantially similar Betätigungskraftverläufe in all operating conditions of a friction clutch are possible.

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 : a schematic diagram of a previously known lever spring,

2 FIG. 2 is a schematic diagram of a lever spring according to the invention, FIG.

3 : A schematic perspective view of an embodiment of the lever spring 2 and

4 : A schematic sectional view of a double clutch with a friction clutch for the lever spring 2 ,

In the 1 illustrated lever spring 10 can be about a rotation axis 12 rotate. The lever spring 10 has a force border 12 on, of which several one-piece spring tongues 14 can protrude radially inward. The spring tongues 14 have at their radially inner end a force application area 16 on, where an actuating system can initiate an actuating force. As a result of the initiated actuating force of the force application area 16 along a Einrückwegs 18 be shifted, causing the lever spring 10 around a circumferential pivot point 20 can be pivoted by changing its taper. In the considered by the spring tongue 14 swept circumferential angle range has the spring tongue 14 together with the force margin provided in the same circumferential angle range 12 a mass center of gravity 22 up to the pivot point 20 has a distance d.

Compared to the in 1 illustrated known lever spring 10 has the in 2 illustrated lever spring according to the invention 10 a designed as a separate component force edge 12 on, so the lever spring 10 not in one piece, but designed in several parts. In the illustrated embodiment, the force edge 12 and the spring tongue 14 arranged one behind the other in the axial direction. This results in the radius range of the force margin 12 a mass of material due to which the center of gravity 22 with a smaller distance d closer to the pivot point 20 is positioned. This may be due to a lower lever arm of the center of mass 22 to the pivot point 20 the influence of centrifugal force at the center of mass 22 acting centrifugal force on the for displacing a pressure plate of a friction clutch by means of the lever spring 10 initiated operating force can be reduced.

As in 3 can show the separate force border 12 For example, with the help of designed as a rivet fasteners 24 with the individual spring tongues 14 be connected. Here, the fasteners carry 24 also to the accumulation of material, whereby the distance d can be further reduced. In particular, the force is 12 made of a different material than the spring tongue 14 made, compared to the material of the spring tongue 14 has a higher density.

In the 4 illustrated double clutch 26 has a first friction clutch 28 and a second friction clutch 30 on, over a common counter-plate 32 indirectly via a designed as a dual mass flywheel torsional vibration damper 34 with a drive shaft 36 a motor vehicle engine are connected. With the counter plate 32 is a clutch cover 38 connected, which is part of the double clutch 26 can cover. At one axial side of the clutch cover 38 is a lever spring 10 indirectly via an adjusting device 40 pivotally supported, with their power 12 indirectly via a tie rod 46 on a first pressure plate 42 the first friction clutch 28 or on a second pressure plate 44 the second friction clutch 30 can attack. This allows the first friction clutch 28 one with a first transmission input shaft 48 a rotatably connected first clutch plate as a dual-clutch transmission automotive transmission 50 Press frictionally. The second friction clutch 30 can one with a second transmission input shaft 52 the motor vehicle transmission rotatably connected second clutch disc 54 Press frictionally.

LIST OF REFERENCE NUMBERS

10

 lever spring

12

 force boundary

14

 spring tongue

16

 Force application area

18

 engagement path

20

 pivot point

22

 Center of gravity

24

 fastener

26

 Double coupling

28

 first friction clutch

30

 second friction clutch

32

 counterplate

34

 torsional vibration dampers

36

 drive shaft

38

 clutch cover

40

 readjustment

42

 first pressure plate

44

 second pressure plate

46

 tie rods

48

 first transmission input shaft

50

 first clutch disc

52

 second transmission input shaft

54

 second clutch disc

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102012221068 A1 [0002]

Claims (10)

Lever spring for relocating a pressure plate ( 42 . 44 ) a friction clutch ( 28 . 30 ), with a radially extending spring tongue ( 14 ) for receiving an actuating force at a radially inner force introduction region ( 16 ) and one at a radially outer end with the spring tongue ( 14 ) separate force border ( 12 ) for transmitting the actuating force to the pressure plate ( 42 . 44 ), wherein in the radial direction between the force introduction region ( 16 ) and the radially outer edge of the force edge ( 12 ) a pivot surface for forming a, in particular circumferential circumferential direction, pivot point ( 20 ) for pivoting the lever spring ( 10 ), wherein a distance (d) of a center of mass ( 22 ) of the spring tongue ( 14 ) and in the radial extension of the spring tongue ( 14 ) proportion of the force ( 12 ) is less to the pivot surface than one with the force edge ( 12 ) integrally designed spring tongue ( 14 ). Lever spring according to claim 1, characterized in that the force edge ( 12 ) a higher density than the spring tongue ( 14 ) having. Lever spring according to claim 1 or 2, characterized in that the force edge ( 12 ) is made of a different material than the spring tongue ( 14 ). Lever spring according to one of claims 1 to 3, characterized in that the force edge ( 12 ) a greater material thickness in the axial direction than the spring tongue ( 14 ) having. Lever spring according to one of claims 1 to 4, characterized in that radially outside the pivot surface an additional mass with the force edge ( 12 ) and / or with the lever spring ( 14 ) connected is. Lever spring according to one of claims 1 to 5, characterized in that the distance d of the center of mass ( 22 ) to the pivot surface with respect to the outer radius R of the force edge ( 12 ) 0.0 ≦ d / R ≦ 0.5, in particular 0.0 ≦ d / R ≦ 0.33, preferably 0.0 ≦ d / R ≦ 0.2, and more preferably 0.0 ≦ d / R ≦ 0 , 1 is. Lever spring according to one of claims 1 to 6, characterized in that the force edge ( 12 ) in a form-fitting manner via a separate fastening means ( 24 ), in particular riveted connection, with the spring tongue ( 14 ) connected is. Cover arrangement for a friction clutch ( 28 . 30 ) for coupling a drive shaft ( 36 ) of a motor vehicle engine having at least one transmission input shaft ( 48 . 52 ) of a motor vehicle transmission with a pressure plate ( 42 . 44 ) for the frictional compression of a clutch disc ( 50 . 54 ) between the pressure plate ( 42 . 44 ) and a counter-plate ( 32 ), one with the drive shaft ( 36 ) coupling clutch cover ( 38 ) and one directly or indirectly on the clutch cover ( 38 ) pivotally supported lever spring ( 10 ) according to one of claims 1 to 7 for the axial displacement of the pressure plate ( 42 . 44 ) in response to an operation of an actuating system in the lever spring ( 10 ) initiable operating force. Lid assembly according to claim 8, characterized in that the lever spring ( 10 ) in the manner of a diaphragm spring by a change in its taper around a circumferentially extending pivot point ( 20 ) is pivotable. Friction clutch for coupling a drive shaft ( 36 ) of a motor vehicle engine having at least one transmission input shaft ( 48 . 52 ) of a motor vehicle transmission with one with the drive shaft ( 36 ) coupling counter plate ( 32 ) for introducing a torque, one with the transmission input shaft ( 48 . 52 ) coupling clutch disc ( 50 . 54 ) and a lid assembly according to claim 8 or 9 for the frictional pressing of the clutch disc ( 50 . 54 ).

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