DE102017109642A1 - Friction clutch with leaf springs and rivets for attachment - Google Patents

Abstract

The invention relates to a friction clutch having an axis of rotation, 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; wherein at least one leaf spring, for transmitting torque and for ensuring a displacement of the pressure plate in the axial direction, 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 is connected; wherein the at least one leaf spring is connected to the clutch cover via at least one rivet, the at least one rivet extending along the axial direction from a first end through the clutch cover and through the at least one leaf spring and with a second end in a recess of Pressure plate is arranged, wherein at least the first end forms a rivet head, wherein the rivet head rests with a bearing surface on the leaf spring, wherein the support surface has a peripheral contour, which is executed out of round.

Description

The invention relates to a friction clutch with leaf springs and a rivet with a special Nietkopfgeometrie, which is used to connect the leaf springs in the friction clutch. The friction clutch is provided in particular 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, in particular, an axis of rotation, 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 each connected via a rivet to the clutch cover, wherein the rivet extends along the axial direction, starting from a first end 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. On the other hand, it has been observed that the leaf springs buckle due to overstress in the circumferential direction.

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 Nietkopfgeometrie 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 at least one axis of rotation, 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. The friction clutch further comprises at least one leaf spring, for transmitting torques and for ensuring a displacement of the pressure plate relative to the counter-plate in the axial direction, wherein the at least one leaf spring 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 is connected. The at least one leaf spring is connected via at least one rivet to the clutch cover, wherein the at least one rivet extends along the axial direction starting from a first end through the clutch cover and through the leaf spring and is arranged with a second end in a recess of the pressure plate , At least the first end of the rivet forms a rivet head, wherein the rivet head rests with a support surface on the leaf spring, wherein the support surface has a peripheral contour, which is executed out of round.

Usually rivets are used with rivet heads, which have a round peripheral contour. Round means here that the peripheral contour is formed by a single radius and thus a largest diameter of the circumferential contour is the same everywhere.

In the case of round rivet heads, it was found that a point contact is formed between the bearing surface of the rivet head and the leaf spring. During operation of the friction clutch (ie when displacing the pressure plate along the axial direction relative to the clutch cover, this creates a concentrated and thus strong voltage increase at the bottom of the leaf spring (ie on the side facing away from the rivet head of the leaf spring). It is now proposed to perform the rivet head out of round. Thereby, a significant reduction of the tension on the leaf spring can be achieved, wherein the rigidity of the leaf spring is unchanged.

In particular, the at least one leaf spring comprises a plurality of leaf springs, which are combined to form a stack and connected as a stack via the first connection and the second connection to the friction clutch.

Preferably, a plurality of leaf springs (or packages of leaf springs), along the circumferential direction of uniformly spaced from each other on the pressure plate and arranged on the clutch cover.

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.

Preferably, the first connection and the second connection are arranged overlapping in a radial direction. In particular, arranged overlapping in the radial direction means that the at least one leaf spring extends substantially in the circumferential direction (and optionally additionally in the axial direction). The first connection and the second connection are then arranged at a substantially equal distance from a rotational axis of the friction clutch.

In particular, the peripheral contour is at least partially formed by a first radius which is at least a factor of two, in particular at least one factor 5 , preferably at least one factor 8th , greater than a largest diameter of the peripheral contour.

Initial calculations have shown that the maximum tension on the underside of the leaf spring can be reduced by up to 18% (compared to a round peripheral contour with the same largest diameter).

In particular, the leaf spring extends between the first connection and the second connection along a circumferential direction and the first connection and the second connection can be connected by a (virtual) straight line; wherein the first radius extends over a first angular range; wherein the rivet head is arranged such that the first angle range is oriented towards the second connection and the straight line is arranged substantially centrally to the first angle range.

Preferably, a length of the peripheral contour formed by the first radius is at least 50% of the largest diameter of the peripheral contour. The length is determined along the circumferential contour (in the first angle range).

• 1: eine bekannte Reibungskupplung in einer Draufsicht;
• 2: eine Reibungskupplung mit einer ersten Ausführungsvariante eines Niets in einer Draufsicht;
• 3: eine Reibungskupplung mit einer zweiten Ausführungsvariante eines Niets in einer Draufsicht;
• 4: eine Reibungskupplung mit einer dritten Ausführungsvariante eines Niets in einer Draufsicht;
• 5: die Reibungskupplung mit der ersten Ausführungsvariante eines Niets in einer Draufsicht;
• 6: einen Niet gemäß der ersten Ausführungsvariante in einer Draufsicht auf das zweite Ende;
• 7: den Niet nach 6 in einer Seitenansicht;
• 8: den Niet nach 6 und 7 in einer Draufsicht auf das erste Ende;
• 9: eine Reibungskupplung mit einer vierten Ausführungsvariante eines Niets in einer Draufsicht; und
• 10: eine Reibungskupplung mit einer fünften Ausführungsvariante eines Niets in einer Draufsicht.

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 a plan view;
• 2 a friction clutch with a first embodiment of a rivet in a plan view;
• 3 a friction clutch with a second embodiment of a rivet in a plan view;
• 4 a friction clutch with a third embodiment of a rivet in a plan view;
• 5 the friction clutch with the first embodiment of a rivet in a plan view;
• 6 a rivet according to the first embodiment in a plan view of the second end;
• 7 : the rivet after 6 in a side view;
• 8th : the rivet after 6 and 7 in a plan view of the first end;
• 9 a friction clutch with a fourth embodiment of a rivet in a plan view; and
• 10 a friction clutch with a fifth embodiment of a rivet in a plan view.

The 1 shows a known friction clutch 1 in a plan view with a rotation axis 2 one, against a counter-plate in an axial direction 3 movable pressure plate 4 for frictionally pressing a between the Counter plate and the pressure plate 4 mountable clutch disc. Several leaf springs 5 for transmitting torques and ensuring a displacement of the pressure plate 4 in the axial direction 3 are, in the circumferential direction 17 spaced from each other, provided. Every leaf spring 5 is on the one hand at a first connection 6 on the pressure plate 4 and on the other hand at a second connection 7 on one, with the counter plate connected clutch cover 8th tethered. The leaf springs 5 are each over a rivet 9 as a connecting element to the clutch cover 8th and on the pressure plate 4 Tied, whereby the rivet 9 along the axial direction 4 starting from a first end 10 through the clutch cover 8th and through the leaf spring 5 extends through.

The leaf springs 5 extend primarily in the circumferential direction 17 , so that pressure plate 4 and counter plate along the axial direction 3 are mutually movable and on the other hand due to the spring force of the leaf springs 5 compressed or pressed apart. In operation of the friction clutch 1 become the leaf springs 5 due to the transmission of torques in the circumferential direction 17 stressed on train and pressure.

Usually, rivets are 9 with rivet heads 12 used a round perimeter contour 14 exhibit. Round means here that the peripheral contour 14 by a single radius 15 is formed and thus a largest diameter 16 the circumferential contour 14 is the same everywhere. For round rivet heads 12 it was found that between the bearing surface 13 the rivet head 12 and the leaf spring 5 a point contact is formed. In operation of the friction clutch 1 (ie when relocating the pressure plate 4 along the axial direction 3 opposite the clutch cover 8th , This creates a concentrated and thus strong voltage overshoot on the underside of the leaf spring 5 (ie on the rivet head 12 opposite side of the leaf spring 5 ). It is now proposed the rivet head 12 out of round. This can significantly reduce the tension on the leaf spring 5 be achieved, the rigidity of the leaf spring 5 unchanged.

2 shows a friction clutch 1 with a first embodiment of a rivet 9 in a top view. At least the first end 10 of the rivet 9 forms a rivet head 12 out, with the rivet head 12 with a support surface 13 on the leaf spring 5 rests, the bearing surface 13 a circumferential contour 14 has, which is executed out of round.

The first connection 6 and the second connection 7 are in a radial direction 21 arranged overlapping. In the radial direction 21 arranged overlapping means that the leaf spring 5 essentially in the circumferential direction 17 (and optionally in addition in the axial direction 3 ). The first connection 6 and the second connection 7 are then at a substantially same distance to a rotation axis 2 the friction clutch 1 arranged.

The peripheral contour 14 is at least partially by a first radius 15 formed by at least a factor of two, here about a factor 10 larger than a largest diameter 16 the circumferential contour 14 , Here, the rivet head is approximately square, with the peripheral contour 14 each of the four side surfaces is formed by a first radius.

3 shows a friction clutch 1 with a second embodiment of a rivet 9 in a top view. 4 shows a friction clutch 1 with a third embodiment of a rivet 9 in a top view. 5 shows the friction clutch 1 with the first embodiment of a rivet 9 in a top view. The 3 to 5 will be described together below. On the comments too 2 will be referred.

The leaf spring 5 extends between the first connection 6 and the second connection 7 along the circumferential direction 17 and the first connection 6 and the second connection 7 are by a (virtual) straight line 18 connectable; where the first radius 15 over a first angle range 19 extends; with the rivet head 12 is arranged so that the first angular range 19 towards the second connection 7 oriented and the straight line 18 substantially centered to the first angular range 19 is arranged.

A length 20 the one by the first radius 15 formed circumferential contour 14 is at least 50% of the largest diameter 16 the circumferential contour 14 , The length 20 becomes along the circumferential contour 14 determined (in the first angle range 19 ).

6 shows a rivet 9 according to the first embodiment in a plan view of the second end 11 , 7 shows the rivet 9 to 6 in a side view. 8th shows the rivet 9 to 6 and 7 in a plan view of the first end 10 , The 6 to 8th will be described together below.

The peripheral contour 14 is at least partially by a first radius 15 formed by at least a factor of two, here about a factor 10 larger than a largest diameter 16 the circumferential contour 14 , Here's the rivet head 12 formed approximately square, wherein the peripheral contour 14 each of the four side surfaces by a first radius 15 is formed.

9 shows a friction clutch 1 with a fourth embodiment of a rivet 9 in a top view. 10 shows a friction clutch 1 with a fifth embodiment of a rivet 9 in a top view. The 9 and 10 will be described together below. On the comments too 2 will be referred.

Here, every rivet head points 12 a circumferential contour 14 on, which is rotationally symmetrical only with respect to a rotation of 360 degrees.

Of course, the rivet described here 9 also at the first connection 6 be used.

LIST OF REFERENCE NUMBERS

1

friction clutch

2

axis of rotation

3

axial direction

4

pressure plate

5

leaf spring

6

first connection

7

second connection

8th

clutch cover

9

rivet

10

first end

11

second end

12

rivet head

13

bearing surface

14

peripheral contour

15

first radius

16

largest diameter

17

circumferentially

18

Just

19

first angular range

20

length

21

radial direction

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 (4)

Friction clutch (1) having a rotation axis (2), a counterplate and a pressure plate (4) displaceable relative to the counterplate in an axial direction (3) for frictionally pressing a clutch disc which can be arranged between the counterplate and the pressure plate (4); wherein at least one leaf spring (5), for transmitting torques and for ensuring a displacement of the pressure plate (4) in the axial direction (3), on the one hand to a first connection (6) on the pressure plate (4) and on the other hand to a second connection (7) is connected to a, connected to the counter-plate clutch cover (8); wherein the at least one leaf spring (5) is connected to the clutch cover (8) via at least one rivet (9), wherein the at least one rivet (9) extends along the axial direction (3) from a first end (10) through the Clutch cover (8) and extending through the at least one leaf spring (5) and with a second end (11) in a recess of the pressure plate (4) is arranged, wherein at least the first end (10) forms a rivet head (12), wherein the rivet head (12) rests with a bearing surface (13) on the leaf spring (5), wherein the bearing surface (13) has a peripheral contour (14) which is non-circular. Friction clutch (1) after Claim 1 wherein the peripheral contour (14) is at least partially formed by a first radius (15) which is at least a factor of two larger than a maximum diameter (16) of the peripheral contour (14). Friction clutch (1) after Claim 2 , wherein the leaf spring (5) between the first connection (6) and the second connection (7) along a circumferential direction (17) and the first connection (6) and the second connection (7) by a straight line (18) connectable are; wherein the first radius (15) extends over a first angular range (19); wherein the rivet head (12) is arranged so that the first angular region (19) oriented towards the second connection (7) and the straight line (18) is arranged centrally to the first angular region (19) Friction clutch (1) according to one of the preceding Claims 2 and 3 wherein a length (20) of the peripheral contour (14) formed by the first radius (15) has at least 50% of the largest diameter (16) of the peripheral contour (14).

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