DE102017119106A1 - Friction clutch for a motor vehicle - Google Patents

Abstract

The invention relates to a friction clutch (1) having a rotation axis (2), a counterplate (3) and a pressure plate (5) which can be displaced in an axial direction (4) relative to the counterplate (3). A leaf spring (6) connects, for transmitting torques and for ensuring a displacement of the pressure plate (5) in the axial direction (4), the pressure plate (5) with a clutch cover (7) connected to the counter plate (3); wherein the pressure plate (5) relative to the clutch cover (7) when a predetermined, by the friction clutch (1) to be transmitted torque in a circumferential direction (8) is relatively rotatable; in which
- The at least one leaf spring (6) via a, in the torque, in the circumferential direction (8) elastically deformable connecting element (9) on the clutch cover (7) or on the pressure plate (5) is connected;
or
- The at least one leaf spring (6) with a first end (10) on the clutch cover (7) and with a second end (11) on one, with the pressure plate (5) connected ramp ring (12) is connected.

Description

The invention relates to a friction clutch for a motor vehicle, in particular for coupling a drive shaft of a motor vehicle with a transmission input shaft of a transmission. The friction clutch comprises a rotation axis, a counterplate and a pressure plate displaceable relative to the counterplate in an axial direction for frictionally pressing a clutch disc which can be arranged between the counterplate and the pressure plate.

From the DE 32 24 403 A1 is such a friction clutch with a rotational axis, a counter-plate and a, relative to the counter-plate in an axial direction displaceable pressure plate for frictionally pressing a can be arranged between the counter-plate and the pressure plate clutch disc known. In this case, leaf springs are provided for transmitting torques and for ensuring a displacement of the pressure plate in the axial direction, which are connected on the one hand to a first connection to the pressure plate and on the other hand to a second connection to a, connected to the counter plate clutch cover. The leaf springs are connected via a respective rivet on the clutch cover, wherein the rivet extends along the axial direction through the clutch cover and through the leaf spring.

The leaf springs extend primarily in the circumferential direction, so that the pressure plate and the counter plate along the axial direction are arranged to be movable relative to each other and on the other hand pressed together or pressed apart due to the spring force of the leaf springs. In operation of the friction clutch, the leaf springs are stressed due to the transmission of torques in the circumferential direction to train and pressure.

It has now been observed that in the operation of friction clutches, these rivet connections of leaf spring and clutch cover can fail. The rivets are sheared off by shear forces acting in the circumferential direction (when pulling). On the other hand, it has been observed that the leaf springs buckle due to overstress in the circumferential direction (in overrun condition).

The object of the invention is to improve the known friction clutches structurally and / or functionally. In particular, the leaf springs should be fixed in such a way that overstressing and thus damage to the leaf springs is prevented.

This object is achieved with a friction clutch according to the features of the independent claim. Further advantageous embodiments of the invention are specified in the dependent formulated claims. The individually listed in the dependent formulated features can be combined in a technologically meaningful way and can define further embodiments of the invention. In addition, the features specified in the claims are specified and explained in more detail in the description, wherein further preferred embodiments of the invention are shown.

It is proposed a friction clutch, in particular for coupling a drive shaft of a motor vehicle with a transmission input shaft of a transmission.

The friction clutch comprises a rotation axis, a counterplate and a pressure plate displaceable relative to the counterplate in an axial direction for frictionally pressing a clutch disc which can be arranged between the counterplate and the pressure plate. At least one leaf spring connects, for the transmission of torques and to ensure a displacement of the pressure plate in the axial direction, the pressure plate with a clutch plate connected to the counter plate. The pressure plate is relatively rotatable relative to the clutch cover when a predetermined, to be transmitted by the friction clutch torque in a circumferential direction is exceeded.

For this purpose, two (mutually independent) embodiments of the friction clutch are proposed.

In the first embodiment, the at least one leaf spring is connected via a, in the torque in a circumferential direction elastically deformable, connecting element on the clutch cover or on the pressure plate. In particular, the connection element is not (or only to a small degree) elastically deformable until it reaches the torque (ie at lower torques).

In particular, the attachment member is made stiff in the axial direction, so that the function of the at least one leaf spring, namely the compression or pressing apart of pressure plate and counter plate along the axial direction thereof is not affected.

In the second embodiment, the at least one leaf spring is rotatably connected to a first end on the clutch cover and with a second end to a, connected to the pressure plate, ramp ring. The ramp ring has at least one, at least partially along the circumferential direction in the axial direction continuously increasing ramp, which cooperates with at least one, with the pressure plate rotatably connected, sliding member, so that the slider moves when the torque is exceeded along the rising ramp in the circumferential direction.

Both embodiments allow for a predeterminable torque relative rotation of pressure plate and clutch cover is made possible. Thus, the connections of the leaf springs and the leaf springs themselves can be protected from overloading. The predetermined torque is in particular at least 50%, preferably at least 75% of a torque, for the transmission of which the friction clutch is designed.

In particular, the at least one leaf spring comprises a plurality of leaf springs, which are folded together to form a stack and connected as a stack via connections (for example via rivets) to the friction clutch.

Preferably, a plurality of leaf springs, along the circumferential direction from each other uniformly spaced from the friction clutch connected.

In particular, the leaf springs are arranged in a radial direction outside or on an outer edge of the pressure plate, the counter plate or the clutch cover.

In particular, the at least one leaf spring is rotatably connected on the one hand to the clutch cover and on the other hand to the connection element and the ramp ring. So here there are just no slots provided on the leaf spring, by which the leaf spring would be displaceable on the one hand or on the other hand in the circumferential direction when the torque is exceeded relative to the clutch cover on the one hand. The relative displacement between the pressure plate and the clutch cover is realized either via the connecting element or via the ramp ring and the sliding element.

The components of rotation axis, counter plate, pressure plate and clutch disc are arranged in particular coaxially with each other.

The attachment element (the first embodiment) is elastically deformable exclusively in the circumferential direction (exclusively) in the case of the torque.

Due to the (only) elastic deformation of the connecting element springs back after each actuation, so that a reproducible behavior of the friction clutch can be ensured even for subsequent operations of the friction clutch.

The connection element can be arranged on the clutch cover. In particular, the connection element is produced in one piece (and together) with the clutch cover by a primary molding process (eg casting) or forming process (eg bending).

Alternatively, the connection element can also be connected to the clutch cover by means of a joining method (eg, by welding technology, or by means of a connecting element, eg, a rivet, that is to say in a form-fitting manner).

The connection element is in particular made of a different material than the clutch cover, z. B. from a spring steel.

The ramp ring (the second embodiment) may be a freewheel, wherein the at least one sliding element in a circumferential direction relative to the at least one ramp movable and in the other circumferential direction (in particular in a pushing operation) by at least one stop is lockable.

In a freewheel ramps are z. B. executed sawtooth. The ramps continuously increase along a circumferential direction in the axial direction and then form a step, so that the slider is blocked in the other circumferential direction by this stop.

Alternatively, the ramp ring may have continuously rising and falling ramps, e.g. B. in the manner of a wave. In this case, relative rotations of pressure plate and clutch cover can be made possible in both directions. The slopes of the ramps increasing in a circumferential direction relative to the descending ramps can be made different, so that, depending on the direction of the stress of the friction clutch, different predetermined torques for a relative rotation must be overcome.

The pressure plate can be aligned with respect to the axis of rotation via at least one centering element, in particular that applies to the second embodiment of the friction clutch. The centering may be required because the pressure plate is not centered directly by the leaf spring when the at least one leaf spring is connected to the ramp ring.

The ramp ring, the at least one sliding element and the pressure plate can with each other be connected axially fixed. Axialfest here means that a displacement of these components relative to each other does not take place in the axial direction. In particular, the at least one sliding element can deform elastically with respect to the pressure plate (only when the torque is reached) (in the axial direction), so that sliding over the ramps, when the torque is exceeded; is possible.

The ramp ring may have a plurality of ramps and the pressure plate may have a (different, in particular smaller) number of sliding elements (in particular corresponding to the number of ramps).

The at least one sliding element may be formed on a ring element, which is non-rotatably (and axially fixed) connected to the pressure plate. The ring element can be arranged coaxially to the pressure plate. The ring element can be made in one piece with the pressure plate or be made in one piece. Preferably, the ring element is connected to the pressure plate via connecting elements (eg rivets).

By way of precaution, it should be noted that the numerical terms used here ("first", "second",...) Primarily (only) serve to distinguish a plurality of similar objects, variables or processes, ie in particular no dependence and / or order of these objects, quantities or mandate processes to one another. If a dependency and / or order are required, this is explicitly stated here or it obviously results for the person skilled in the art when studying the concretely described embodiment.

• 1: eine bekannte Reibungskupplung in perspektivischer Ansicht;
• 2: ein vergrößertes Detail der 1 in perspektivischer Ansicht;
• 3: ein weiteres Detail der Reibungskupplung nach 1 und 2 in einer Seitenansicht entlang der radialen Richtung im Schnitt;
• 4: eine erste Ausführungsvariante einer Reibungskupplung in einer Seitenansicht entlang der radialen Richtung im Schnitt;
• 5: eine zweite Ausführungsvariante einer Reibungskupplung in einer Draufsicht entlang der axialen Richtung; und
• 6: einen Ausschnitt eines Rampenrings mit Gleitelementen in einer Ansicht entlang der radialen Richtung.

The invention and the technical environment will be explained in more detail with reference to FIGS. It should be noted that the invention should not be limited by the embodiments shown. In particular, unless explicitly stated otherwise, it is also possible to extract partial aspects of the facts explained in the figures and to combine them with other components and findings from the present description and / or figures. In particular, it should be noted that the figures and in particular the illustrated proportions are only schematic. The same reference numerals designate the same objects, so that explanations of other figures can be used if necessary. Show it:

• 1 a known friction clutch in perspective view;
• 2 : an enlarged detail of the 1 in perspective view;
• 3 : another detail of the friction clutch after 1 and 2 in a side view along the radial direction in section;
• 4 a first embodiment of a friction clutch in a side view along the radial direction in section;
• 5 a second embodiment of a friction clutch in a plan view along the axial direction; and
• 6 a section of a ramp ring with sliding elements in a view along the radial direction.

The 1 shows a known friction clutch 1 in perspective view. 2 shows an enlarged detail of 1 in perspective view. 3 shows another detail of the friction clutch 1 to 1 and 2 in a side view along the radial direction 18 on average. The 1 to 3 will be described together below.

The 1 to 3 show a friction clutch 1 with a rotation axis 2 , a counter-plate 3 (please refer 3 ) and one, opposite the counter plate 3 in an axial direction 4 movable pressure plate 5 for frictionally pressing one between the counter-plate 3 and the pressure plate 5 mountable clutch disc. Several leaf springs 6 for transmitting torques and ensuring a displacement of the pressure plate 5 in the axial direction 4 are, in the circumferential direction 8th spaced from each other, provided. Every leaf spring 6 is on the one hand to a connection to the pressure plate 5 and on the other hand, at a connection to one, with the counter-plate 3 connected clutch cover 7 tethered. The leaf springs 6 are each a rivet as a connecting element 19 on the clutch cover 7 tethered, with the rivet along the axial direction 4 through the clutch cover 7 and through the leaf spring 6 extends through.

The leaf springs 6 extend primarily in the circumferential direction 8th , so that pressure plate 5 and counter plate 3 along the axial direction 4 are mutually movable and on the other hand due to the spring force of the leaf springs 6 compressed or pressed apart. In operation of the friction clutch 1 become the leaf springs 6 due to the transmission of torques in the circumferential direction 8th stressed on train and pressure.

It has now been observed that in the operation of friction clutches 1 these rivet joints of leaf spring 6 and clutch cover 7 can fail. The rivets are through in the circumferential direction 8th acting shear forces sheared off (in train operation). On the other hand, it was observed that the leaf springs 6 due to overstress in the circumferential direction 8th , buckling (in overrun mode).

4 shows a first embodiment of a friction clutch 1 in a side view along the radial direction 18 in section (similar view as in 3 ).

The friction clutch 1 includes a rotation axis 2 , a counter-plate 3 (please refer 3 ) and one, opposite the counter plate 3 in an axial direction 4 movable pressure plate 5 , At least one leaf spring 6 connects, for the transmission of torque and to ensure a displacement of the pressure plate 5 in the axial direction 4 , the pressure plate 5 with one with the counter plate 3 connected clutch cover 7 , The pressure plate 5 is opposite the clutch cover 7 when a predetermined, through the friction clutch 1 torque to be transmitted in a circumferential direction 8th relatively rotatable.

In the first embodiment shown here is the leaf spring 6 over, at the torque in a circumferential direction 8th elastically deformable, connecting element 9 on the clutch cover 7 tethered. The connection element 9 is in the axial direction 4 rigid, so that the function of the leaf spring 6 , namely the compression or squeezing of pressure plate 5 and counter plate 3 along the axial direction 4 , will not be affected.

5 shows a second embodiment of a friction clutch 1 in a plan view along the axial direction 4 , 6 shows a section of a ramp ring 12 with sliding elements 14 in a view along the radial direction 18 , The 5 and 6 will be described together below.

In the second embodiment, the leaf spring 6 with a first end 10 rotatably (a relative rotation of leaf spring 6 and clutch cover 7 in the circumferential direction 8th is not possible) on the clutch cover 7 and with a second end 11 on one, with the pressure plate 5 connected, ramp ring 12 tethered. The ramp ring 12 has a plurality, each along the circumferential direction 8th in the axial direction 4 at least partially continuously increasing ramps 13 on. One ramp each 13 (but not every ramp 13 ) works with one, with the pressure plate 5 rotatably connected, sliding element 14 together, so that the sliding element 14 when the torque is exceeded along the rising ramp 13 in the circumferential direction 8th (together with the pressure plate 5 ) emotional.

This is a predeterminable torque relative rotation of pressure plate 5 and clutch cover 7 allows.

The ramp ring 12 Here is a freewheel, where the sliding element 14 in a circumferential direction 8th opposite the respective ramp 13 movable and in the other circumferential direction 8th through a stop 15 is lockable.

At the ramp ring 12 are the ramps 13 sawtooth executed. The ramps 12 increase along a circumferential direction 8th in the axial direction 4 continuously and then form a step or a stop 15 so that the sliding element 14 in the other circumferential direction 8th through this stop 15 is blocked.

The pressure plate 5 is via a centering element 16 opposite the axis of rotation 2 aligned.

The ramp ring 12 , the sliding element 14 and the pressure plate 5 are connected to each other axially. Axialfest here means that a displacement of these components relative to each other in the axial direction 4 not happened. The sliding element 14 deform against the pressure plate 5 (only when reaching the torque) elastic (in the axial direction 4 ), allowing a slide over the ramps 13 , if the torque is exceeded; is possible.

The sliding elements 14 are on a ring element 17 trained, with the pressure plate 5 rotatably (and axially) is connected. The ring element 17 is coaxial with the pressure plate 5 arranged.

LIST OF REFERENCE NUMBERS

1

friction clutch

2

axis of rotation

3

counterplate

4

axial direction

5

pressure plate

6

leaf spring

7

clutch cover

8th

circumferentially

9

connecting element

10

first end

11

second end

12

ramp ring

13

ramp

14

Slide

15

attack

16

centering

17

ring element

18

radial direction

19

connecting member

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 3224403 A1 [0002]

Claims (8)

Friction clutch (1) having a rotation axis (2), a counter-plate (3) and, relative to the counter-plate (3) in an axial direction (4) displaceable pressure plate (5) for frictionally pressing a between the counter-plate (3) and the pressure plate (5) disposable clutch disc; wherein at least one leaf spring (6), for transmitting torques and for ensuring a displacement of the pressure plate (5) in the axial direction (4) connects the pressure plate (5) with a clutch cover (7) connected to the counter plate (3); wherein the pressure plate (5) relative to the clutch cover (7) when a predetermined, by the friction clutch (1) to be transmitted torque in a circumferential direction (8) is relatively rotatable; in which - The at least one leaf spring (6) via a, in the torque, in the circumferential direction (8) elastically deformable connecting element (9) on the clutch cover (7) or on the pressure plate (5) is connected; or - The at least one leaf spring (6) with a first end (10) rotatably connected to the clutch cover (7) and with a second end (11) on one, with the pressure plate (5) connected to the ramp ring (12) is connected; wherein the ramp ring (12) has at least one ramp (13) which increases at least partially continuously along the circumferential direction (8) in the axial direction (4) and which is connected to at least one sliding element (14) which is non-rotatably connected to the pressure plate (5). cooperates, so that the sliding member (14) moves when the torque is exceeded along the rising ramp (13) in the circumferential direction (8). Friction clutch (1) after Claim 1 , wherein the connecting element (9) is elastically deformable at the torque only in the circumferential direction (8). Friction clutch (1) according to one of the preceding claims, wherein the connecting element (9) on the clutch cover (7) is arranged. Friction clutch (1) after Claim 1 in which the ramp ring (12) is a freewheel, in which the at least one sliding element (14) is movable in one circumferential direction (8) relative to the at least one ramp (13) and in the other circumferential direction (8) by at least one stop (15). is lockable. Friction clutch (1) according to one of the preceding Claims 1 and 4 , wherein the pressure plate (5) via at least one centering element (16) relative to the axis of rotation (2) is aligned. Friction clutch (1) according to one of the preceding Claims 1 and 4 and 5 , wherein the ramp ring (12), the at least one sliding element (14) and the pressure plate (5) are connected to each other axially fixed. Friction clutch (1) according to one of the preceding Claims 1 and 4 to 6 wherein the ramp ring (12) has a plurality of ramps (13) and the pressure plate (5) comprises a plurality of sliding elements (14). Friction clutch (1) according to one of the preceding Claims 1 and 4 to 7 in which the at least one sliding element (14) is formed on a ring element (17) which is non-rotatably connected to the pressure plate (5).

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