FR2731056A1 - MOTOR VEHICLE FRICTION CLUTCH WITH AUTOMATIC WEAR COMPENSATION - Google Patents

Abstract

In a motor vehicle friction clutch, with automatic wear compensation, there is provided at least one play transmission element 9 acting, by means of an actuating lever 12 directed radially inwards, on a take-up device, which is arranged opposite the pressure plate 4, and which consists of an annular element 18 produced in the form of a sheet metal ring concentrically surrounding the axis of rotation 3. Thanks to the combination of these two elements, a single play transmission element may be sufficient, which makes it possible to obtain a generally economical manufacturing construction method.

Description

The invention relates to a friction clutch of a motor vehicle,

  with automatic wear compensation for the pressure plate assembly, which is fixed to a flywheel, with the interposition of a clutch disc comprising friction linings, and which in common with the flywheel, forms a axis of rotation, the clutch comprising a pressure plate fixed in rotation but axially movable in a clutch housing, and a diaphragm spring, which is inserted under preload between the pressure plate and the clutch housing , and which, in the area of its outer periphery and in an area of smaller diameter, rests on the clutch housing as well as on a support of the pressure plate, the support being effected with interposition of '' a take-up device allowing axial movement of the

  pressure in the direction of a spring removal-

  diaphragm and in accordance with the wear of the linings of

clutch disc friction.

  German patent application document 43 06 688 already discloses a motor vehicle friction clutch, which comprises a device intended for automatic compensation of the wear of the friction linings. This state of the art recommends conical, radially movable elements which, after the appearance of wear, produce a corresponding increase in distance between the diaphragm spring and the pressure plate, thanks to a movement taking place radially towards the outside. Such wear compensation works perfectly correctly, when several elements of

  game transmission distributed on the periphery.

  Furthermore, document DE-OS 44 12 107 discloses an automatic wear compensation device, consisting of two annular elements, which are arranged concentric to the axis of rotation, which are stressed by a spring force. one against the other in the peripheral direction, and which support one another by means of partial surfaces making a slope, and correspondingly increasing, during wear, the distance

  between the diaphragm spring and the pressure plate.

  The object of the present invention is to provide a friction clutch of a motor vehicle with an automatic wear compensation system, which can be manufactured according to the simplest and economical method of construction, while retaining

perfect functioning.

  According to the invention, this object is achieved by the following solution characterized in that at least one game transmission element is provided, which is disposed on the pressure plate assembly, and which acts, with a lever actuation directed radially inwards, directly or indirectly on a part of the take-up device, in that the play transmission element is mounted so as to be able to slide axially and to be locked by friction, in an opening arranged parallel to the axis of rotation in the pressure plate, in that the play transmission element has a fixed axial stop of the casing, which limits its movement in the direction of the flywheel, and in that the take-up device, during the declutching phase following the appearance of wear, engages in the increased distance between the play transmission element and the pressure plate, the take-up device and ant consisting of at least one annular element, which is arranged concentrically with the axis of rotation, bears peripherally on a guide diameter of the pressure plate, is of a rigid configuration in the axial direction, has on a frontal side, partial surfaces achieving an axial slope in the peripheral direction, and is biased in the peripheral direction, by a spring system, in the direction of a relative rotation and thus of an increase in overall dimensions axial. Thanks to this arrangement, it has proved possible to reduce the number of game transmission elements, without causing any operating restrictions. In most cases, using just one game transmission element may be sufficient; in the case of critical clutches, it may be necessary to use two play transmission elements which would then be arranged approximately diagonally opposite. This simplification is made possible by the fact that the annular element is guided precisely over a guide diameter of the pressure plate, produced concentrically with the axis of rotation, and is of a rigid configuration in the direction of the axis. For this purpose, the annular element can be guided on an internal diameter, which allows it to be of an open configuration in the peripheral direction. However, it is also possible to provide guidance on an outside diameter, but in this case it is necessary to have an annular element.

  closed in the peripheral direction.

  According to another characteristic of the invention, the conjugate partial surfaces intended to increase the axial size, can be produced in the pressure plate, in the diaphragm spring, or in a second annular element disposed in axial alignment with the first. . It is thus possible, on the one hand to be satisfied with a single annular element thereby reducing the number of different parts, and on the other hand to also provide two annular elements, which simplifies assembly in the sense that '' it is possible to mount beforehand the sub-assembly formed by the annular elements and the spring device provided for the relative rotational movement of the two

annular elements.

  In the context of the invention, the annular element advantageously has a rectangular cross section, the longest side being guided parallel to the axis of rotation over a guide diameter of the pressure plate, so that the element ring can be easily manufactured, for example by

  die cutting, from a metal strip.

  Furthermore, each game transmission element is biased by a spring for the purpose of blocking in the opening of the pressure plate. This spring jams the play transmission element in the opening of the pressure plate, to achieve an automatic blocking during all operating states, except take-up of wear. In this case, this spring bears on the actuation lever and on the pressure plate. It can, by the choice of support points, generate a sufficient wedging effect, despite a low force

spring elastic.

  In addition, each play transmission element is biased, in the region of the opening, by a spring intended for axial sliding, by biasing the play transmission element relative to the pressure plate, in the direction of the flywheel, which essentially serves to obtain the initial adjustment during assembly of the friction clutch, thanks to the fact that each game transmission element is brought to bear on a fixed part with the casing, for example the flywheel. The game transmission element is advantageously guided in a bore by a sliding pin extending parallel to the axis of rotation, and the spring is arranged concentrically around the sliding pin, and is supported by a part on the pressure plate and on the other hand on the sliding spindle (for example a head 15 thereof). Thus, the spring is guided by

  reliably and space-saving.

  According to another characteristic of the invention, each game transmission element comprises a rotation lock in the opening, preferably made in the form of a bore, this blockage being in the form of a pin parallel to the bore and located at a radial distance from it. It is thus guaranteed that the game transmission element subjected to centrifugal force, retains its necessary position, relative to the pressure plate. In addition, the second spring intended for blocking the game transmission element is arranged so concentric around the pin, which blocks the transmission element of] against a relative rotation, this spring urging the actuating arm so as to move it away from the pressure plate. The pin thus ensures both the locking in rotation and the guiding of this spring considered. In the following, the invention will be explained in more detail with regard to an exemplary embodiment shown in the single figure of the accompanying drawings, which

  shows an axial section of a friction clutch.

  The friction clutch 1 is fixed to a flywheel 2 of an internal combustion engine, this flywheel being capable of turning around the axis of rotation 3. It consists of a clutch housing 6, which usually is screwed onto the flywheel 2. Between the flywheel 2 and the clutch housing 6 is provided a pressure plate 4, which is fixedly connected in rotation to the clutch housing 6, but is guided movably in the axial direction. For this purpose, tangential spring blades are usually used here, not shown. Between the pressure plate 4 and the flywheel 2 is disposed the clutch disc 5 with its friction linings 23. Between the pressure plate 4 and the clutch housing 6 is provided a diaphragm spring 7 which in the area of medium diameter, is pivotally mounted by means of several spacer pins 8 fixed to the clutch housing 6, and which, in the area of its outside diameter, acts on the pressure plate 4, in the direction of tightening of the friction linings 23 between the pressure plate 4 and the flywheel 2. Radially inwards, the diaphragm spring 7 is provided with spring tongues 17, which can be actuated by a system of clutch not shown. Between the diaphragm spring 7 and the pressure plate 4 is provided a device intended for the automatic compensation of wear. This consists of at least one annular element 18, which extends concentrically with the axis of rotation 3 and is guided in a

  guide diameter 22 of the pressure plate 4.

  The annular element 18 is shown in a partial detail in top view, and has a planar peripheral edge, as well as, on the opposite side, several partial surfaces 20 inclined in the peripheral direction, which are opposite corresponding mating surfaces. The annular element 18 is biased in the peripheral direction, by a spring 21, which, for example, is hooked by one of its ends, in the openings 19. The annular element 18 can, for example, as shown in longitudinal section, cooperate with a second annular element 18a, the two annular elements 18, 18a being arranged so as to be aligned in the axial direction. In this case, the annular element 18a has surfaces conjugated with the partial surfaces 20 and resting on them. In the present case, the annular element 18a is supported on the pressure plate 4, and the element

  annular 18 is biased by the diaphragm spring 7.

  In the case of the existence of these two annular elements 18, 18a, the spring 21 acts between the two annular elements and biases them in such a way that, thanks to the reciprocal rise of the partial surfaces 20 and of the partial surfaces conjugated on each other. the others, the annular elements tend to achieve an increase in size. However, it is also possible to use, without problem, only one annular element 18 whose partial surfaces 20, which cooperate, for example, with partial surfaces conjugated directly on the pressure plate 4, or else these partial surfaces 20 are produced opposite the diaphragm spring 7, and the diaphragm spring then has the corresponding conjugate partial surfaces. The friction clutch 1 is equipped with at least one play transmission element 9, which comprises a sliding pin 10 extending parallel to the axis of rotation 3, through the pressure plate 4. This pin is of preferably of round configuration, and the opening in the pressure plate 4 is consequently produced in the form of a bore 24. The sliding pin 10 has, at its end directed towards the flywheel 2, a head 15. Between this head 15 and the pressure plate 4, a first spring 13 is arranged, which biases the play transmission element 9 in the direction of the flywheel 2. The sliding pin 10 is provided, on its side opposite to that directed towards the flywheel, an actuating lever 12 which extends radially inwards and which, during wear-free operation, blocks the play transmission element 9 in the bore 24, by appropriate wedging . A second spring 14 contributes to this jamming, this spring being arranged around the pin 11, which is arranged in the pressure plate, parallel to the axis of rotation 3, and which serves as a rotation lock for the actuating lever 12 through an appropriate opening in the actuating lever 12. The radially inner end of the actuating lever 12 extends, seen in the axial direction, between the zone of outside diameter of the diaphragm spring 7 and the plate pressure 4, as far as against the annular element 18. For this purpose, the annular element 18 is provided with a separate, corresponding recess 25, as shown in the separate illustration. In the disengaged state of the friction clutch, the wedging between the play transmission element 9 and the bore 24 in the pressure plate is reinforced by the spring 21 and the surfaces

partial 20.

  Now, the operating mode of the friction clutch 1 is as follows: during assembly, in the engaged state of the friction clutch, care is taken, having interposed the clutch disc 5, that the head 15 of the game transmission element 9 comes to bear on the flywheel 2. The annular element 18 is, on this occasion, adjusted against the force of the spring 21, so as to present, during this mounting phase, a small axial distance to the radially inner end of the actuating lever 12. After mounting, the annular element 18 is released and turns by a certain amount, under the effect of the force of the spring 21, namely until the axial space between the pressure plate 4 and the actuating lever 12, is filled by the annular element 18. The diaphragm spring 7 rests on this occasion on the edge of the annular element 18, opposite to that directed towards the pressure plate 4, and is located distance from the actuating lever 12. The slope of the partial surfaces 20 is here dimensioned in such a way that the force of the diaphragm spring 7 cannot produce relative movement of the annular element 18, in the peripheral direction. If now, during a start-up phase under high load, wear occurs at the friction linings 23, then the pressure plate 4 moves under the effect of the force of the diaphragm spring 7, common with the annular element 18, of the value of wear, in the direction of the flywheel 2. Due to the support of the sliding spindle 10, with its head 15, on the flywheel 2, the game transmission 9 cannot follow this relative movement of the pressure plate 4 in the direction of the flywheel 2. In this operating state, the diaphragm spring 7 neutralizes the friction tightening between the sliding spindle 10 and the bore 24. It thus occurs, between the radially inner end of the actuating lever 12 and the annular element 18, in the region of the recess 25, a space corresponding to wear at the friction surfaces 23. At the during the next declutching phase, when the spring tabs 17 are moved in the direction of the flywheel 2, by the declutching system, and the diaphragm spring, in the region of its outside diameter, performs a reverse movement, it is possible, thanks to the force of the spring 21, to make rotate the annular element 18 about the axis of rotation 3, whereby, due to the oblique partial surfaces 20, the space with respect to the actuating lever 12 is filled, and this lever is then found again in

  axial connection without play with the pressure plate 4.

  In the next clutch phase, the distance

  axial between the radially outer zone of the spring-

  diaphragm 7 and the pressure plate 4, is increased by the value of the previous wear, so that in

  the clutched state of the friction clutch, the spring-

  diaphragm 7 has retained its initial mounting position.

  This ensures that the diaphragm spring always works in the same force range, that the actuating forces are always kept at the same level, and that it is possible to establish the torque transmission capacity of the clutch. friction and

to respect it.

  It should be noted that the radially inner end zones of the actuating levers 12 can also be arranged in such a way that they rest on the side of the diaphragm spring 7, opposite to that directed towards the flywheel 2, and do not thus indirectly controlling the compensation movement of the annular element 18. In the case of such a configuration, the actuation levers 12 serve simultaneously for the forced release movement

  pressure plate 4 during the declutching phase.

  The other functions remain unchanged. Instead of an annular element 18, it is also possible to mount one after the other in the axial direction, two annular elements 18, 18a, which have the partial surfaces 20 and corresponding mating surfaces, directed respectively towards each other, and the spring 21 exerts its force on the two annular elements, with a view to a relative rotation of the two annular elements with respect to each other. However, it is possible to use only one annular element 18, the surfaces conjugated to the partial surfaces 20 can then be arranged, either in the pressure plate 4, or also in the diaphragm spring 7. The annular element 18 can, in a particularly simple manner, be cut by stamping, from a sheet metal strip, and be bent into a ring, and used in the form of an open ring, in the case of the example shown. If however the guide diameter 22 is in the form of an outer diameter, it is preferable that the annular element 18 is closed in the peripheral direction. The fact of making the annular element 18 relatively rigid, despite a simple construction method, makes it possible in most cases to achieve the desired function using a single game transmission element 9. Only in exceptional cases, it may be necessary to provide for two elements

  9 game transmission distributed on the periphery.

Claims (9)

CLAIMS.   1. Motor vehicle friction clutch, with automatic wear compensation for the pressure plate assembly, which is fixed to a flywheel, with the interposition of a clutch disc comprising friction linings, and which in common with the flywheel, forms an axis of rotation, the clutch comprising a pressure plate fixed in rotation, but axially   movable in a clutch housing, and a spring-   diaphragm, which is inserted under preload between the pressure plate and the clutch housing, and which, in the region of its outer periphery and in an area of smaller diameter, rests equally well on the clutch housing, that on a pressure plate support, the support being effected with the interposition of a take-up device allowing an axial displacement of the pressure plate in the direction of a distance from the diaphragm spring and in accordance with the wear of the linings friction of the clutch disc, characterized in that at least one clearance transmission element (9) is provided, which is arranged on the pressure plate assembly, and which acts, with an actuating lever ( 12) directed radially inwards, directly or indirectly on a part of the take-up device (18, 18a), in that the play transmission element (9) is mounted so as to be able to slide axially and to be locked by friction, in a opening (24) arranged parallel to the axis of rotation (3) in the pressure plate (4), in that the play transmission element (9) has an axial stop (2, 15) fixed to the housing, which limits its movement towards the flywheel (2), and in that the take-up device (18, 18a), during the declutching phase following the appearance of wear, engages in the distance having increased between the play transmission element and the pressure plate, the take-up device consisting of at least one annular element (18), which is arranged concentrically with the axis of rotation (3), s' peripherally presses on a guide diameter (22) of the pressure plate (4), is of a rigid configuration in the axial direction, present on a front side, partial surfaces (20) providing an axial slope in the direction peripheral, and is solicited in the peripheral direction, by a res system sort (21), in the direction of a relative rotation and thus a   increase in axial dimensions.   2. Friction clutch according to claim 1, characterized in that the conjugate partial surfaces can be produced in the pressure plate (4), in the diaphragm spring (7), or in a second annular element (18a) arranged in alignment axial with the first.   3. Friction clutch according to claim 2, characterized in that the annular element (18, 18a) has a rectangular cross section, the longest side being guided parallel to the axis of rotation (3) over a diameter of guide (22) of the pressure (4).   4. Friction clutch according to claim 1, characterized in that each game transmission element (9) is biased by a spring (14) with a view to blocking in the opening (24) of the plate pressure (4).   5. Friction clutch according to claim 4, characterized in that the spring (14) bears on the actuation lever (12) and on the plate pressure (4).   6. Friction clutch according to claim 1, characterized in that each game transmission element (9) is biased, in the region of the opening (24), by a spring (13), with a view to a   axial sliding towards the flywheel (2).   7. Friction clutch according to claim 6, characterized in that the play transmission element (9) is guided in a bore (24) by a sliding pin (10) extending parallel to the axis of rotation ( 3), and in that the spring (13) is arranged concentrically around the sliding spindle (10), and rests on the one hand on the pressure plate (4) and on the other hand on the spindle sliding (10) (by example a head 15 thereof).   8. Friction clutch according to claim 1, characterized in that each game transmission element (9) comprises a rotation lock in the opening preferably made in the form of a bore (24), this blocking being under the shape of a pin (11) parallel to the bore (24) and located at radial distance from it.   9. Friction clutch according to claim, characterized in that the second spring (14) is arranged concentrically around the pin (11), and biases the actuating arm so as to move it away from the pressure plate.