FR2886997A1 - PUSHED DIAPHRAGM CLUTCH COMPRISING A DIAPHRAGM JOINT WITH GAME COMPENSATION - Google Patents

Abstract

The high-diaphragm clutch comprises a cover (1), a pressure plate (15), a diaphragm (7) mounted prestressed between the cover (1) and the pressure plate (15), and means (23, 25, 27) of articulation of the diaphragm (7) relative to the cover (1) .These hinge means are of the game compensation type and comprise a ring (23) and a counter-ring (27) provided with ramps (31). ) and against ramps (33) allowing, under the action of resilient means (32), to maintain the counter-ring (27) in contact with the periphery (19) of the diaphragm (7) regardless of the wear imposed by this diaphragm to this counter-crown (27).

Description

The present invention relates to a high diaphragm clutch

  comprising a compensating diaphragm hinge.

  Such a clutch, used in particular in the automotive field, typically comprises a cover, a pressure plate, a diaphragm mounted prestressed between the cover and the pressure plate, and means for articulating this diaphragm relative to the cover.

  In the engaged position, the diaphragm exerts on the pressure plate sufficient forces to lock the clutch disc and thus allow the transmission of engine torque to the gearbox.

  In the disengaged position, the periphery of the diaphragm is moved away from the pressure plate, which then moves away from the clutch disk under the effect of resilient return means, thus making it possible to stop transmitting the torque from the engine to the gearbox and, if necessary, make the necessary gear changes.

  It was found that following a large number of clutches, the means of articulation of the diaphragm relative to the lid tended to wear (we speak of matting) under the effect of repeated movements of the diaphragm, and that he thus ended up appearing games between these means of articulation and the diaphragm.

  The appearance of such games has the effect of reducing the stroke of the periphery of the diaphragm when it is pushed by the clutch abutment, and thus reduce the travel of the pressure plate during the transition from the engaged position to the disengaged position.

  As a result of this, after a certain period of time, it is no longer possible to perform a complete disengagement, that is to say to eliminate any contact between the pressure plate and the clutch disc linings. : part of the engine torque and continues to be transmitted to this disc, which makes it difficult, if not impossible changes gear ratio.

  FR 2 548 301 discloses a device to solve this problem: this device comprises wedge-shaped clearance compensation elements, which can move radially under the effect of the centrifugal force when the clutch is in position engaged.

  By their wedge shape, these elements can thus compensate for the games that appear gradually due to wear (or matting) means of articulation of the diaphragm relative to the lid.

  Although quite satisfactory, this solution has disadvantages: in practice, all the compensation elements do not move exactly at the same amplitude towards the periphery of the diaphragm, which results in the compensation of the games between the means of articulation and the diaphragm is not uniform and therefore that the forces printed at the diaphragm by the hinge means during disengagement are unequally distributed.

  These differences in effort fatigue the diaphragm prematurely, affect the homogeneity of the contact between the periphery of the diaphragm and the pressure plate and, in general, reduce the longevity of the clutch.

  The present invention is intended to overcome this disadvantage.

  This object of the invention is achieved with a high diaphragm clutch comprising a cover, a pressure plate, a diaphragm mounted prestressed between said cover and said pressure plate, and means for articulating said diaphragm with respect to said cover, these hinge means being of the clearance compensating type and comprising: - a fixed ring relative to said cover, located between said pressure plate and said diaphragm, - a counter-ring freely mounted between said ring and said diaphragm, said crown and against-crown being respectively provided with ramps and against-ramps slightly inclined relative to the mean plane of said crown and against-crown, - elastic return means tending to rotate said counter-crown relative to said ring in a direction where under the effect of the sliding of said counter-ramps on said ramps, said counter-ring moves axially away from said ring, so that said counter-crown remains in abutment against said diaphragm irrespective of the wear caused by this diaphragm to this counter-crown.

  Thanks to the presence of the crown and its associated counter-crown, a device is obtained for evenly distributing the compensation of the clearances between the articulation means and the diaphragm. In this way, compensating compensation inequalities inherent in the device of the prior art are dispensed with.

  According to an optional feature of the present invention, said ramps and counter-ramps form an angle of between 1 and 10 degrees with respect to said average plane, and preferably about 3 degrees.

  Such a slope is adapted to prevent that when moving to the disengaged position, where the diaphragm strongly presses against the crown, it does not approach the axle axially.

  According to other optional features of the present invention: said elastic means are arranged to work in extension, - said elastic means are arranged to work in compression, - said elastic means comprise a plurality of springs interposed between said ring and said counter-crown, - said springs are connected to said crown and countersunk by means of fixing studs, - said elastic means are distributed regularly, or in regular groups, on said crown and counter-crown.

  Other features and advantages of the present invention will appear on examining the attached drawing board, in which: - Figure 1 shows an axial section of a clutch according to the invention, in the engaged position, - FIG. 2 represents an exploded perspective view of a part of this clutch, on which clutch clearance compensation means are visible; FIG. 3 represents a perspective view of the elements of FIG. 2, in position assembly, and - Figure 4 shows a partial view in the direction IV of Figure 3 of the game compensation means of the clutch.

  Referring now to Figure 1 in which we see that the clutch according to the invention comprises a cover 1 connected by suitable fastening means 3 to a flywheel 5 itself mounted on the shaft of a motor for example of the internal combustion type (not shown).

  Between the cover 1 the flywheel 5 are arranged, in this order: a diaphragm 7, a game compensation device 9, a pressure plate 15 and a clutch disc 17.

  The diaphragm 7 is mounted prestressed between the cover 1 and the pressure plate 15.

  This diaphragm comprises, in the manner of a Belleville washer, on the one hand a peripheral part 19 full and on the other hand fingers 21 which extend radially towards the inside of the diaphragm from the peripheral part 19.

  The game compensation device 9 comprises a ring 23 fixedly mounted relative to the cover 1 by appropriate fixing means such as rivets 25 passing between the fingers 21 of the diaphragm 7 (see FIGS. 1 and 4 in FIG. represented only one of these rivets).

  The game compensation device 9 also comprises a countercourt 27 which cooperates with the ring 23.

  The ring 23 and the counter-ring 27 can be obtained by machining or stamping.

  Referring more particularly to Figures 2 to 4, it can be seen that the periphery of the ring 23 and the counter-ring 27 respectively comprise ramps 31 and counter-ramps 33 cooperating with each other.

  These ramps and counter-ramps are evenly distributed around the periphery of the ring 23 and the counter-ring 27 and form a small angle α relative to the mean plane P of the clearance compensation device 9.

  The angle a is preferably in a range of 1 to 10 degrees and is preferably about 3 degrees (centigrade).

  The counter-crown 27 is simply interposed between the peripheral portion 19 of the diaphragm 7 and the crown 23.

  In other words, when the peripheral portion 19 of the diaphragm 7 exerts no force on the counter-crown 27, the latter can move freely relative to the ring 23.

  Referring now more particularly to Figures 2 and 3 on which it can be seen that resilient means such as springs 32 are interposed between the ring 23 and against the crown 27.

  More specifically, the two ends of each spring 32 are respectively fixed to a stud 34 secured to the ring gear 23 and to a stud 35 secured to the counter-ring 27.

  A plurality of centering pins 50, only one of which is visible in FIGS. 2 and 3, are regularly distributed on the ring 23.

  These pins, which may for example be three in number, are intended to center the counter-ring 27 relative to the ring 23, so as to ensure a homogeneous support of the counter-ring against the diaphragm 7 and a reduction of the false parallelism of the pressure plate 15 during a clutch.

  Preferably, the springs 32 are evenly distributed on the ring 23 and against the crown 27, or in regular groups, as shown in Figure 2 (3 groups of three springs).

  The springs 32 are arranged so that under the effect of the restoring forces they exert, the counter-crown 27 has a tendency to pivot relative to the ring gear 23 in the direction which has the effect of axially crown 27 of the crown 23 under the effect of the sliding of the counter-ramps 33 on the ramps 31.

  Two variants are possible: a variant where the springs 32 work in traction, as shown in Figures 2 and 3, and a variant not shown in which the springs 32 would work in compression.

  The pressure plate 15 comprises a shoulder 37 cooperating with the peripheral portion 19 of the diaphragm 7 and, opposite this shoulder, a friction surface 39 (see Figure 1).

  The pressure plate 15 is movable in the direction of the axis A of the clutch.

  The clutch disk 17 supports at its periphery linings 41 capable of being gripped between the friction surface 39 of the pressure plate 15 and the flywheel 5.

  The mode of operation and advantages of the clutch according to the invention result directly from the foregoing description.

  In Figure 1 the clutch according to the invention is shown in the engaged position.

  In this position, a small thrust force (also called residual force), typically of the order of 5 kg, is exerted on the free ends of the fingers 21 of the diaphragm 7.

  Under these conditions, and because the diaphragm 7 is prestressed between the cover 1 and the pressure plate 15, the peripheral portion 19 of this diaphragm exerts on the shoulder 37 of the pressure plate efforts to pinch the lining 41 of the disk clutch 17 between the friction surface 39 of the pressure plate and the flywheel 5.

  Note that it can advantageously be provided that the peripheral portion 19 of the diaphragm 7 bears on the cover 1 by means of a bead or rod 43 formed or not of material with this cover.

  When the clutch according to the invention is in this engaged position, the peripheral portion 19 of the diaphragm 7 exerts no axial force on the counter-crown 27.

  Thus, under the action of the springs 32, this counter-crown 27 can pivot relative to the ring gear 23 and thus, under the effect of the sliding of the counter-ramps 33 on the ramps 31, move axially away from this ring, towards the peripheral portion 19 of the diaphragm 7.

  During a disengagement, axial thrust forces F (see FIG. 1) are exerted on the free ends of the fingers 21 of the diaphragm 7.

  In doing so, the peripheral portion 19 of the diaphragm 7 is supported on the counter-crown 27 and in this way a lever effect is obtained by which the free edge 45 of the diaphragm 7 approaches the cover 1, as indicated by arrow D of FIG.

  In other words, the counter-ring 27 allows, via the ring 23 and the rivets 25, the articulation of the diaphragm 7 with respect to the cover 1.

  In doing so, and thanks to appropriate means of reminders and not shown, the pressure plate 15 moves away from the linings 41, which makes it possible to break the transmission of the engine torque to the clutch disc 17.

  During this disengagement operation, the axial forces exerted by the peripheral portion 19 of the diaphragm 7 on the counter-crown 27 are considerable.

  However, because of the low slope of the ramps 31 and against ramps 33, these axial forces fail to cause a rotation of the counter-ring 27 relative to the ring 23 in the direction that would be likely to bring this axially against crown of this crown.

  It is now understood that the game compensation device 9 allows, when the clutch is in the engaged position, to make up the clearances that can appear between the counter-ring 27 and the peripheral portion 19 of the diaphragm 7 due to wear (or matting) of this counter-crown by this peripheral part 19.

  It is also understood that this catch-up of games is irreversible, that is to say that during a clutch operation consecutive to this catching of games, the counter-ring 27 remains in the axial position that it has reached, which allows to keep, for the free edge 45 of the peripheral portion 19 of the diaphragm 7, a sufficient stroke to ensure complete release of the lining 41 of the clutch plate 17 by the pressure plate 15.

  It will be understood that, by virtue of its annular configuration, the counter-crown 27 exerts, during the disengagement, efforts uniformly distributed over the peripheral portion 19 of the diaphragm 7, and that thus the clearance compensation is homogeneous.

  In this way, the disadvantages associated with the device of the prior art, described in the preamble of the present description, are overcome.

  Of course, the present invention is not limited to the embodiment described and shown, provided by way of illustrative and non-limiting example.

  Thus, the invention could be incorporated in a clutch mechanism comprising a double damping flywheel, and / or a dual-disc and / or a flexible flywheel, and / or a wear-compensating mechanism.

Claims (7)

  1. A diaphragm push-type clutch comprising a cover (1), a pressure plate (15), a diaphragm (7) mounted prestressed between said cover (1) and said pressure plate (15), and means (23, 25, 27) of articulation of said diaphragm (7) with respect to said cover (1), these articulation means being of the clearing type and comprising: - a ring (23) fixed relative to said cover (1), located between said pressure plate (15) and said diaphragm (7), a counter-ring (27) freely mounted between said ring (23) and said diaphragm (7), said ring (23) and counter-ring (27). ) being respectively provided with ramps (31) and against ramps (33) slightly inclined relative to the mean plane (P) of said ring (23) and countercurrent (27), - resilient return means (32) tending to rotate said counter-ring (27) with respect to said ring (23) in a direction where, under the effect of the sliding of said counter-ramps (3) 3) on said ramps (31), said counter-ring (27) moves axially away from said ring (23), so that said counter-ring (27) remains in abutment against said diaphragm (7) regardless of the wear caused by this diaphragm (7) to this against-crown (27).   2. Clutch according to claim 1, wherein said ramps (31) and counter-ramps (33) form an angle (a) between 1 and 10 degrees relative to said mean plane (P), and preferably about 3 degrees.   3. Clutch according to one of claims 1 or 2, wherein said resilient means (32) are arranged to work in extension.   4. Clutch according to any one of claims 1 to 3, wherein said resilient means are arranged to work in compression.   5. Clutch according to any one of the preceding claims, wherein said elastic means comprise a plurality of springs (32) interposed between said ring (23) and said counter-ring (27).   6. Clutch according to claim 5, wherein said springs (32) are connected to said ring gear (23) and counter-ring (27) by means of fixing studs (34, 35).   7. Clutch according to one of claims 5 or 6, wherein said resilient means (32) are regularly distributed, or in regular groups, said crowns (23) and counter-crown (27).