WO2008064634A1

WO2008064634A1 - Self-adjusting friction clutch

Info

Publication number: WO2008064634A1
Application number: PCT/DE2007/002011
Authority: WO
Inventors: Sebastien Oster; Karl-Ludwig Kimmig; Marco Becht; Lászlo MAN; Christoph Raber
Original assignee: Luk Lamellen Und Kupplungsbau Beteiligungs Kg
Priority date: 2006-11-27
Filing date: 2007-11-08
Publication date: 2008-06-05
Also published as: DE112007002601A5

Abstract

In a self-adjusting friction clutch comprising a housing (10, 12), a pressing plate (14) that is connected to the housing so as to be rotationally fixed, but axially displaceable, a lever spring (20) provided between the housing and the pressing plate, the inner circumferential edge of which is axially displaceable for moving the pressing plate, a driving spring (28) equipped with a radial slot (31), wherein the driving spring comprises a detection tongue (40) and an adjustment tongue (34), wherein the tongues engage in gears of a component (24, 54) that can be rotated relative to the driving spring such that a free-running state exists in a direction of the relative rotation between the component and the tongues and locking occurs in the opposite direction. The driving spring deforms with an axial displacement of the pressing plate while conically reducing the outside diameter thereof such that the detection tongue traverses the gear in the event of an above-threshold deformation, and the component rotates relative to the driving spring in a free-running state between the adjustment tongue and the associated gear upon completion of the super-critical deformation, causing an axial support length between the lever spring and the pressing plate to change relative to the associated counter-surfaces due to a displacement of ramp surfaces.

Description

Self-adjusting friction clutch

The invention relates to a self-adjusting friction clutch with a housing, a rotatably connected to the housing, but axially limited movable pressure plate, provided between the housing and the pressure plate, a total annular disk-shaped lever spring which is supported on a housing-fixed ring bearing and the inner peripheral edge for moving the Pressure plate is axially movable.

A peculiarity of friction clutches is that friction linings of a clutch disc wear during operation. In order to achieve the same contact pressure and thus the same transmittable torque despite the resulting thinner clutch disc, an adjustment must be made so that the position or deformation of the annular disc-shaped lever spring remains constant regardless of the wear of the friction linings.

The invention has for its object to provide a self-adjusting friction clutch, which ensures a reliable wear adjustment with a simple structure.

This object is achieved by a self-adjusting friction clutch with a housing, a rotatably connected to the housing, but axially limited movable pressure plate, provided between the housing and the pressure plate, a total annular disk-shaped lever spring which is supported on a housing-fixed ring bearing and whose inner peripheral edge to Moving the pressure plate is axially movable, provided with a radial slot annular disc-shaped drive spring, one of the slot adjacent end radially outward has a Detektierzunge and the other, the slot adjacent end radially outward a Nachstellzunge which tongues in teeth of a relative to the drive spring engaging such rotatable member that there is a freewheel in a direction of relative rotation between the component and the tongues and in the opposite direction blocking takes place, which drive spring at an axial Movement of the pressure plate with reduction of its outer diameter conically deformed so that at a suprathreshold deformation, the Detektierzunge the toothing over and at the completion of the supercritical deformation, the component is rotated under freewheel between the Nachstellzunge and the associated teeth relative to the drive spring, resulting in an axial support length between the lever spring and the pressure plate changed due to a displacement of ramp surfaces relative to associated mating surfaces. With the inventively provided, provided with a Detektierzunge and a Nachstellzunge drive spring is achieved by their occurring during an actuation of the clutch deformation, which is associated with a reduction in the outer diameter, that the Nachstellzunge when exceeding a predetermined wear since a previous adjustment along the associated To move toothing of the rotatable relative to the drive member and the component during its re-deformation by the engagement between Nachstellzunge and the associated toothing causes a relative rotation between the drive spring and the component, whereby an adjustment of the clutch takes place.

Advantageously, an embodiment of the friction clutch is such that the component rotatable relative to the drive spring is a ramp ring over which the lever spring is supported on the pressure plate, wherein the axial support length depends on circumferentially directed ramp surfaces of the rotational position of the ramp ring, the drive spring is in an axial direction on the ramp ring and radially spaced apart in the axial opposite direction on a housing-fixed abutment is supported and provided with the Nachstellzunge, the slot adjacent end portion of the drive spring is fixed by a fixed housing stop in the circumferential direction.

The ramp ring is a relatively easy to manufacture component, and can serve directly for centering the drive spring.

Preferably, the Detektierzunge and the Nachstellzunge are designed as elastically resilient arms, at the free ends of which at least one tooth is provided, which is urged by deformation of the arm in engagement with the toothing of the ramp ring.

Further, the ramp ring is preferably formed in the circumferential direction in its axial thickness increasing ramp surfaces, which cooperate with corresponding, formed on the rotatable relative to the housing pressure plate counter surfaces.

In a preferred embodiment of the friction clutch, the pressure plate is pressed by the inherent rigidity of the lever spring in abutment against friction linings of a clutch disc and the drive spring is deformed suprathreshold with increasing wear of the friction linings. To avoid unintentional readjustment, the detection tongue and the adjusting tongue can be designed such that they can not be released simultaneously from the associated toothings.

In this case, the formation of the friction clutch may be such that the ends of the Detektierzunge and the Nachstellzunge overlap radially and engage in radially opposite directions in associated teeth, wherein a radial distance between the overlapping tongues in their engagement with the associated teeth is smaller than that Sum of the depths of the gears.

Another way to avoid an unintentional adjustment, for example, as a result of high acting on the entire coupling spins, is that on the relative to the drive spring rotatable component, a locking pin is attached, which allows a free coming of the Detektierzunge from the associated teeth only when Do not rotate the component and the drive spring together in the freewheeling direction.

Another way to avoid unintentional adjustment is that between the Detektierzunge and an adjacent peripheral edge portion of the drive spring mounted on the drive spring locking wedge is arranged, which allows a free coming of the Detektierzunge from the associated teeth only in suprathresholded drive spring.

The invention is explained below with reference to schematic drawings, for example, and with further details.

In the figures represent:

1 Axialhalbschnitte a friction clutch and partial supervision on a drive to 6 spring in different operating states of the clutch,

FIG. 7 shows a perspective view of a drive spring,

8 shows a perspective view of a pressure plate, FIG. 9 is a perspective view of a ramp ring;

10 partial views of a drive spring with a device for preventing unintentional up to 13 adjustment,

Fig. 14 partial views of a drive spring with an alternative means for Verhin- 16 tion of an undesired adjustment and

17 partial views of a drive spring with a further embodiment of a device for preventing an unwanted adjustment.

According to FIGS. 1 to 9, a self-adjusting friction clutch contains a cover 10, which is rigidly connected to a counter-plate 12 and forms a housing together with it. With the housing is non-rotatably, but axially limited movable, a pressure plate 14 is connected, between which and the counter plate 12 is provided with a friction linings 16 clutch disc 18 which is non-rotatably connected to a shaft, not shown, for example, a transmission input shaft.

For axial displacement of the pressure plate 14 is a rotatably connected to the housing, pivoting, generally annular disk-shaped plate spring or lever spring 20, which is supported on the housing via a ring bearing 22 and is supported on the pressure plate 14 via a ramp ring 24. In order to limit the mobility of the radially outer peripheral region of the lever spring 20 when it is correspondingly actuated, a housing-fixed stop 26 is provided.

At the pressure plate 14 facing side of the ramp ring 24, a drive spring 28 is supported, which is centered by the ramp ring 24 at the same time and which rests against a housing-fixed abutment 30.

The drive spring 28, which is shown in perspective in Figure 7, is a generally designed as a plate spring annular disk-shaped component, which is not closed in the circumferential direction, but has a slot 31.

Of a slot 31 adjacent to the end portion 32 of the drive spring 28 is in the circumferential direction and the slot 31 partially overlapping a Nachstellzunge 34 before. The Nachstellzunge 34 is formed as an arm having at its free end a pawl-like, at least one tooth having, radially outwardly directed teeth 36.

The end portion 32 opposite end portion 38 is formed with a Detektierzunge 40 which overlaps a radially thinned portion of the drive spring 28 in the same circumferential direction as the Nachstellzunge 34 and is also designed as an arm, the free end of an outwardly facing pawl-like teeth 42nd having at least one tooth.

The drive spring 28, which forms a plate spring as a whole, has circumferentially spaced-apart recesses 44, which support their deformability and between which the drive spring is supported on the housing. By trained on the housing lugs that engage in the recesses, the radial mobility of the drive spring and its mobility can be determined in the circumferential direction.

As can be seen in particular from Figure 1, which is provided with the Nachstellzunge 34 end portion 32 of the drive spring 28 by engagement between a fixed housing pin 45 (Figure 1) in an end region 32 adjacent recess 44 of the drive spring 28 in the circumferential direction, whereas the with the Detektierzunge 40 provided end portion 38 of the drive spring 28 can move in the circumferential direction.

Figure 8 shows the pressure plate 14 in a perspective view. Clearly visible on the pressure plate trained ramp surfaces 48 which are spaced in the circumferential direction and whose axial thickness changes in each case in the circumferential direction.

Figure 9 shows in perspective the ramp ring 24, on the radial outer side of the ramp surfaces 48 corresponding ramps 50 are formed, which rest on the ramp surfaces 48. As can be readily understood from FIGS. 8 and 9, the axial distance between the pressure plate 14 and the ramp ring 24 depends on the angular position of the ramp ring 24 relative to the pressure plate 14. As can also be seen from FIG. 9, the ramp ring is formed on its radially inner side with toothings 52 which are provided for engagement with the toothings 36 and 42 of the adjusting tongue 34 and the detection tongue 40, respectively.

The following describes the function of the coupling: By the prestressed lever spring 20, a contact force between the pressure plate 14 and the counter-plate 12 is generated, which urges the friction linings 16 in frictional engagement with the pressure plate 14 and the counter-plate 12 and allows a torque transmission of the clutch. By pivoting the lever spring 20 according to Figure 1 in the clockwise direction around the ring bearing 22 acting on the pressure plate 14 bias of the lever spring 20 is released to interrupt the torque transmission. The axial travel of the pressure plate 14, the ramp ring 24 and the lever spring 20 are limited by the stop 26.

By pivoting the lever spring 20 or an axial displacement of the pressure plate 14 and the ramp ring 24, the conicity of the drive spring 28 changes, with Konitätsve- ränderungen associated with a change in diameter. These changes in diameter are possible by changing the width of the slot 31 of the drive spring 28.

The engagement between the teeth 36 and 42 of the Nachstellzunge 34 and the Detektier- tongue 40 and the teeth 52 of the ramp ring 24 is such that in the example of Figures 1 to 6 in a relative direction of rotation between the drive spring 28 and the ramp ring 24 with a rotation the drive spring 28 is formed in the clockwise direction a freewheel, ie the teeth 42 and 36 can override the teeth 52, whereas in the other direction of relative rotation a block is formed.

In the following, an adjustment cycle will be explained with reference to the figure sequence of Figures 1 to 6, as it is required to hold the actuating forces of the clutch and in particular the position of the lever spring 20 fully engaged and fully disengaged clutch regardless of wear of the friction linings 16:

It is first assumed (Figure 1) with the clutch is closed, the pressure plate 14 is pressed by the force of the lever spring 20 against the friction linings 16, so that the clutch transmits torque. In this position, the drive spring 28 has a taper or a diameter at which the teeth 36 and 42 are in engagement with the teeth 52.

To release the friction clutch, the lever spring 20 is pivoted in the clockwise direction (Figure 2), whereby the group pressure plate 14, ramp ring 24 and drive spring 28 moves according to Figure 2 to the right, the torque transmission is interrupted and the drive spring 28 changes its taper. The tooth engagement between the ramp ring 24 and the Detektierzunge 40 remains locked, whereas the teeth 36 of the Nachstellzunge 34 is released from the teeth 52 of the ramp ring, but without jumping into its adjacent teeth. In particular, to ensure this, the stop 26 is provided.

When the friction linings 16 wear, the pressure plate 14 moves together with the ramp ring according to the figures 1 to 6 to the left, the lever spring 20 follows this movement and continues to apply the necessary contact pressure. The movement to the left leads to an increasing conicity of the drive spring 28 (FIG. 3), whereby the width of the slot 31 is reduced and the toothing 42 of the detection tongue 40 is released from the toothing 52 and, in the event of excessive wear, jumps into the adjacent teeth of the toothing 52 (FIG. see FIG. 4). For example, a tooth jump may be a shift between 0.5 mm and 3.0 mm.

In a subsequent operation of the friction clutch, the lever spring 20 is pivoted again to interrupt the torque transmission. In this case, the drive spring 28 in turn changes its conicity and the slot 31 assumes its original width again, wherein the Detektierzunge 40 of the drive spring 28 rotatably drives the ramp ring 24. In this case, the teeth 36 of the Nachstellzunge 34 passes over the teeth 52 of the ramp ring in the sense of a freewheel (Figure 5) and comes into engagement with the following teeth (Figure 6). In this way, the ramp ring 24 has rotated by at least one tooth. This results in a change in the effective thickness of the assembly pressure plate 14 and ramp ring 24 due to the engagement between the ramps 50 of the ramp ring 24 and the ramp surfaces 48 of the pressure plate 14, whereby wear of the friction linings 16 is compensated. The wear adjustment can be done, for example, in steps between 0.1 mm and 0.5 mm.

The adjustment according to the invention by means of the drive spring 28, which causes a relative rotation in the circumferential direction between two over ramp surfaces in axial mutual contact components, can be used in a variety of couplings, such as depressed couplings, towed clutches, compressed couplings, pressed double clutches, etc. Due to the interaction between Detektierzunge, Nachstellzunge and their respective locking in a circumferential direction and freewheeling in the opposite direction engagement with a counter toothing is achieved that the Detektierzunge as a result of überschwelligem Reibbelagverschleiß first a new, in the circumferential direction displaced intermeshing engagement causes, which then leads to a wear adjustment, in which the Nachstellzunge comes in a new meshing.

A problem that can occur quite generally with a wear adjustment made by means of tooth engagement is that, for very large rotational angular accelerations of the clutch, there is an undesired rotational movement between the drive spring and a component which is rotationally displaced therefrom, for example the ramp ring, in the freewheeling direction of the toothing can. This would correspond to an unwanted reenactment. In the following, possibilities are given, how such an unwanted adjustment can be avoided. In the following figures, the same reference numerals as previously used for components that are functionally similar to the previously described components. The teeth 52 formed on a component which is rotated relative to the drive spring at a wear adjustment need not necessarily be formed on a ramp ring, but may be formed on the housing or the lever spring or elsewhere, so that this relatively twisted Component is provided with the reference numeral 54.

According to Figure 10, the drive spring 28 is formed with the Nachstellzunge 34 and Detektierzunge 40 which protrude in the illustrated embodiment in opposite directions of end portions and whose trained at their end portions gears 36 and 42 overlap. The toothing 36 is directed radially outward and engages in a corresponding toothing 52 of the component 54 to be rotated. The toothing 42 is directed radially inwardly and engages in a radially outwardly directed counter toothing 52 of the component 54 a. The toothing interventions are such that the drive spring 28 can be rotated freely running in the clockwise direction relative to the component 54, whereas the toothings lock in the opposite direction.

The distance a between the backs of the sensing or Detekierzunge 40 and the Nachstellzunge 34 is a tooth height plus the sum of possible manufacturing tolerances. Mutual detection or readjustment is possible in this way. However, both gears can not disengage simultaneously, since in this case the Detektierzunge and the Nachstellzunge abut with their backs to each other. A simultaneous freewheeling is therefore not possible. The blocking is guaranteed. FIG. 11 shows the state in which the two toothings can not at the same time be completely released from one another since the backs of the adjusting tongue and the detection tongue are in mutual contact.

FIG. 12 shows the state in which the toothing of the detection tongue 40 is free from the counter-toothing, whereas the toothing of the adjusting tongue 34 is in engagement with the counter-toothing 52.

FIG. 13 shows the state in which the toothing of the detection tongue 40 engages in the counter-toothing 52, whereas the toothing of the adjusting tongue 34 is free of the toothing 52.

A further possibility will be explained with reference to FIGS. 14 to 16, as an undesired adjustment as a result of high rotational accelerations can be avoided. The Nachstellzunge 34 and the Detektierzunge are in turn directed the same in this example and provided with radially outwardly directed teeth, which engage in a counter-toothing 52 of the component 54.

Upon sensing, the detection tab 40 moves relative to the component 54, which may be, for example, the lever spring 20 (FIG. 1). In an unintentional readjustment due to high angular acceleration, the drive spring 28 and the component 54 move together. To prevent this, a locking pin 56 is rigidly attached to the component 54. The locking pin 56 is provided with a skew, which corresponds to the inclination of the free end surface of the Detektierzunge 40 whose direction corresponds approximately to the direction in which the Detektierzunge 40 can move out of the teeth 52. As can be seen directly from the figures, the system between the beveled surfaces of the locking pin 56 and the Detektierzunge 40 inhibits movement of the Detektierzunge from the teeth 52 when the locking pin 56 and thus the component 54 together with the drive spring 28 due to very high angular accelerations in Move the circumferential direction. On the other hand, if no contact force between the locking pin 56 and the Detektierzunge 40 is effective, this can, as shown in Figure 15, free from the teeth 52 and get into a subsequent group of teeth (Figure 16).

While the possibility described with reference to FIGS. 10 to 13 of preventing undesired readjustment makes it possible to use a plurality of readjusting tongues. restricts (thereby reduces the Nachstellschrittweite), the solution according to Figures 14 to 16 can be realized with multiple Nachstellzungen.

A further possibility of suppressing unwanted readjustment is explained with reference to FIGS. 17 to 19:

According to FIGS. 17 to 19, a blocking wedge 58 is provided which normally fills a gap between the detection tongue 40 and an outer contour of the drive spring 28. This locking wedge 58 is elastically yielding connected to the drive spring 28 via a connection region 60. The shape of the locking wedge 58 is matched to that of the free end of the Detektierzunge 40 so that it does not come out of the teeth 52 without a predetermined amount exceeding deformation of the drive spring 28. Only with a suprathreshold deformation of the drive spring 28, as occurs for example for the purpose of Sensierens or detecting suprathreshold wear of the friction linings, the locking wedge 58 can move relative to the Detektierzunge 40 and thereby release their mobility from the teeth 52 out into an adjacent group of teeth (see Figures 18 and 19).

LIST OF REFERENCE NUMBERS

Cover Counterplate Clamping plate Friction lining Clutch disc Lever spring Ring bearing Ramp ring Stopper Drive spring Counter bearing Slot End area Adjustment tongue Gearing End area Detection tongue Gearing Gap Spigot Ramp area Ramp Gearing relative to component to be rotated Locking pin Locking wedge Connection area

Claims

claims

1. Self-adjusting friction clutch with a housing (10, 12), a rotationally fixed to the housing, but axially limited movable contact pressure plate (14) provided between the housing and the pressure plate, a total annular disc-shaped lever spring (20) on a housing-fixed ring bearing (22) is supported and the inner peripheral edge for moving the pressure plate is axially movable, one provided with a radial slot (31) annular disc-shaped drive spring (28) whose one, the slot adjacent end portion (38) radially outwardly a Detektierzunge (40) and whose other, the slot adjacent end portion (32) radially outwardly a Nachstellzunge (34), which tongues in teeth (52) of a relative to the drive spring rotatable member (24, 54) engage such that in a direction of relative rotation between the component and the tongues a free-wheeling exists and in the opposite direction a blockage takes place, which Antr iebsfeder be conically deformed with an axial movement of the pressure plate while reducing its outer diameter, so that at a suprathreshold deformation of the detection tongue passes over the teeth and at the end of the supercritical deformation, the component under free running between the Nachstellzunge and the associated toothing twisted relative to the drive spring, whereby an axial support length between the lever spring and the pressure plate due to a displacement of ramp surfaces (48) relative to associated counter-surfaces (50) changed.

2. A friction clutch according to claim 1, wherein the relative to the drive spring (28) rotatable member is a ramp ring (24) through which the lever spring (20) on the pressure plate (14) is supported, wherein the axial support length directed at circumferentially ramp surfaces (48, 50) depends on the rotational position of the ramp ring, the drive spring is supported in an axial direction on the ramp ring and radially spaced in the axial opposite direction on a housing fixed abutment (30) and provided with the Nachstellzunge (34), the slot (31) adjacent end portion (32) of the drive spring is fixed by a fixed housing stop (45) in the circumferential direction.

3. friction clutch according to claim 2, wherein the Detektierzunge (40) and the Nachstellzunge (34) are formed as elastically resilient arms, at the free ends of which at least one tooth (36, 42) is provided, which by deformation of the arm in engagement with the Gearing (52) of the ramp ring (24) is urged.

4. A friction clutch according to claim 2 or 3, wherein the ramp ring (24) is formed with ramps (50) having in the circumferential direction in its axial thickness increasing ramp surfaces (48) of the relative to the housing (10, 12) rotatable pressure plate (14). interact.

5. Friction clutch according to one of claims 2 to 4, wherein the pressure plate (14) by the inherent rigidity of the lever spring (20) in contact with friction linings (16) of a clutch disc (18) is pressed and the drive spring (28) with increasing wear of the friction linings is suprathreshold deformed.

6. A friction clutch according to any one of claims 1 to 5, wherein the Detektierzunge (40) and the Nachstellzunge (34) are formed such that they can not be released simultaneously from the associated teeth (52).

A friction clutch according to claim 6, wherein the ends of the detection tab (40) and the adjuster tab (34) overlap radially, engage in radially opposite directions in associated serrations (52) and a radial distance between the overlapping tabs as they engage the corresponding toothing is smaller than the sum of the depths of the teeth.

8. A friction clutch according to any one of claims 1 to 5, wherein on the relative to the drive spring (28) rotatable member (54) a locking pin (56) is mounted, which only allows a free coming of the Detektierzunge (40) from the associated toothing (52) if the component and the drive spring do not rotate together in the freewheeling direction.

9. Friction clutch according to one of claims 1 to 5, wherein between the Detektierzunge (40) and an adjacent peripheral edge portion of the drive spring (28) mounted on the drive spring locking wedge (58) is arranged, the free coming of the Detektierzunge from the associated toothing (52 ) only possible with suprathreshold deformed drive spring.