FR3062442B1 - CLUTCH MECHANISM, IN PARTICULAR FOR A MOTOR VEHICLE - Google Patents

Abstract

The invention relates to a clutch mechanism (1), particularly for a motor vehicle, comprising a cover (2), a pressure plate (3) movable relative to the cover (2) along an axis of the mechanism, a diaphragm (12). ) movable between an engaged position and a disengaged position, able to actuate the displacement of the pressure plate (3), wear compensating means interposed between the diaphragm (12) and the pressure plate (3).

Description

Clutch mechanism, in particular for a motor vehicle

The present invention relates to a wear-catching clutch mechanism, in particular for a motor vehicle.

A clutch device conventionally comprises a reaction plate, a clutch mechanism comprising a movable pressure plate, and a friction disk mounted between said reaction and pressure plates. The movement of the pressure plate is controlled by a diaphragm, itself controlled by a clutch abutment.

The clutch abutment may be of the actuator type controlled by an electronic computer, hydraulic control, or cable control in order to exert a predetermined force on the diaphragm and move it into a disengaged position.

The pressure plate is thus movable between a clutch position in which the friction disk is clamped between said pressure and reaction plates, and a disengaging position in which the friction disk is released.

The use of the clutch device causes wear of the friction disc liners and the counter-materials of the associated pressure and reaction plates. This results in a variation of the position of the pressure plate relative to the associated diaphragm and / or with respect to the reaction plate, generating a variation of the friction disk clamping force and a modification of the licking point and the stroke of the clutch stop. It is recalled that the licking point is the position from which a torque can be transmitted through the clutch device.

A wear-catching clutch device is known from the document FR 2 847 626 in the name of the Applicant. This document discloses a wear-compensating clutch device for a motor vehicle, comprising a pressure plate intended to bear against a friction disc of the clutch device, a diaphragm serving to actuate the pressure plate between a fully engaged position in which said pressure plate is pushed against the friction disk, and a fully disengaged position in which said pressure plate is moved away from the friction disk by means of return means of the pressure plate.

The pressure plate, the friction disk and the diaphragm are housed in a cover which is fixed with respect to the reaction plate.

The device further comprises a compensating member of the wear of the friction disc, interposed between the diaphragm and the pressure plate, and movable in rotation about an axis in a determined range, said catch member comprising a co-operating ramp. with a counter-boom turned on the side of the pressure plate, so as to adjust the distance between the diaphragm and the pressure plate and compensate the wear of the friction disc according to the position of the ramp relative to the counter-pressure ramp.

The clutch device further comprises displacement means comprising a ratchet wheel adapted to pivot about an axis mounted on a cassette but integrally supported by the cover at the ends of the axis. The displacement means also comprise a pawl comprising a body fixed on the cover and an actuating tab cooperating with the ratchet wheel so as to actuate the pivoting of the ratchet wheel in case of wear. The ratchet wheel is coupled in rotation to a worm mounted around the aforementioned axis and meshing with a toothing of the catch member. Thus, the rotation of said ratchet wheel causes the retraction member to move in order to compensate for the wear.

In general, the lid is made by stamping a steel sheet. The axis is conventionally engaged in a hole of the cover, the end or ends of the hole being partially closed by localized deformation of the material, for example by notching. The axis is thus held in position relative to the lid.

There is currently a tendency to increase the torque from the engine to be transmitted through the clutch device, without increasing the bulk of the latter.

For this purpose, it is planned to replace the stamped steel sheet cover with a molded cast iron cover, for example cast aluminum alloy or carbon alloy cast iron. A local deformation of material by notching is feasible in the case of a cast iron lid but requires a deep and delicate development of the process, because of the risk of cracking said lid.

The invention therefore aims to propose an alternative solution for fixing the axis on the lid.

For this purpose, it proposes a clutch mechanism, in particular for a motor vehicle, comprising:

a cover, a movable pressure plate relative to the cover along an axis of the mechanism, a diaphragm movable between an engaged position and a disengaged position, able to actuate the displacement of the pressure plate (3), wear compensating means interposed between the diaphragm and the pressure plate, said catching means comprising ramp means cooperating with counter-lamp means so that the rotation of the ramp means relative to the counter-ramp means changes the distance between the diaphragm and pressure plate, and means for rotating the ramp means, housed at least partly in a cassette and mounted at least partly around an axis, said axis being mounted in the cassette and being supported by the cover, characterized in that the axis is retained or fixed to the cover by screwing.

Of course, this solution is applicable to any type of lid and is not limited to cast iron covers.

The lid can thus be a stamped steel lid or a cast iron cover obtained by casting.

The cover obtained by molding allows freedom of shape which facilitates the integration of the screwed axis. It is in particular possible to have a material allowance located at the level of the thread receiving the bolted axis.

The axis may comprise a threaded portion, screwed into a threaded portion of the cover.

The axis may comprise a threaded portion, cooperating with a fixed nut relative to the lid.

The nut can be housed in a hole or recess in the lid.

The axis can form a screw and have a head, resting on a surface of the cover or housed in the corresponding hole of the cover.

The axis can be housed in at least one hole of the cover, the axis being immobilized in said hole of the cover by a screw engaged in a threaded portion of said hole of the cover. The screw is coaxial with the axis.

The axis can be housed in at least one hole of the cover, the axis being immobilized in said hole of the cover by a screw engaged in a hole of the cover whose axis is parallel to the axis of rotation of the clutch mechanism .

The screw engaged in the hole is distinct from the axis.

The screw or the threaded part of the shaft can be held in the threaded part of the cover or the nut by means of a threadlock, or by locking with a suitable tightening torque.

The cassette may comprise a base having two lateral edges from which extend two lateral flanks, the axis of the cassette passing through the lateral flanks.

The lid can be obtained by casting aluminum alloy cast iron or carbon alloy cast iron.

The lid may comprise two studs, each end of the axis being engaged in one of the studs of the lid. The studs can be obtained by molding.

The cassette can be positioned circumferentially between the two studs.

The displacement means may comprise a ratchet wheel pivotable about the axis, an endless screw rotatably coupled to the ratchet, the worm meshing with a toothing of the ramp means, and a pawl having a body fixed on the cover and an actuating tab cooperating with the ratchet wheel to actuate the pivoting of the ratchet wheel in case of wear, the rotation of said ratchet wheel causing the movement of the ramp means to compensate for the 'wear.

Furthermore, the cassette may comprise means capable of limiting its rotation relative to the lid, around the aforementioned axis. These means may be formed by a tab adapted to bear on a bearing surface of the lid.

The invention also relates to a device comprising a clutch mechanism of the aforementioned type, characterized in that it comprises a reaction plate, the friction disc being able to be clamped between the pressure plate and the reaction plate in position. engaged and released in the disengaged position, the cover being fixed relative to the reaction plate.

The invention will be better understood and other details, characteristics and advantages of the invention will appear on reading the following description given by way of non-limiting example with reference to the accompanying drawings in which:

FIG. 1 is a view in axial section of a clutch mechanism, according to a first embodiment of the invention,

FIG. 2 is an exploded view, in perspective, of a part of the clutch mechanism of FIG. 1,

FIG. 3 is a sectional view of part of the mechanism of FIGS. 1 and 2,

FIG. 4 is a view corresponding to a second embodiment of the invention,

FIG. 5 is a view corresponding to a third embodiment of the invention,

FIG. 6 is a view corresponding to a fourth embodiment of the invention,

FIG. 7 is a view corresponding to a fifth embodiment of the invention,

FIGS. 8 and 9 are views corresponding to FIG. 3, FIG. 3, FIG. 3, FIG. 3, FIG. 3, illustrating illustrating illustrating illustrating illustrating a sixth embodiment of the invention,

FIG. 10 is a view corresponding to FIG. 3, illustrating a seventh embodiment of the invention,

- Figure 11 is a view corresponding to Figure 3, illustrating an eighth embodiment of the invention.

Figures 1 to 3 show a clutch mechanism 1 to take up wear according to a first embodiment of the invention. It comprises an annular fixed cover 2 of axis X, intended to be fixed on a reaction plate 2a, an annular pressure plate 3 and movable along the axis X with respect to the reaction plate and the cover 2. A friction disc 3a is intended to be interposed axially between the pressure plate 3 and the reaction plate. The lid 2 is fixed to the reaction plate 2a by six fixing screws 52.

More particularly, the cover 2 comprises an annular portion 4 extending generally radially and studs 5a, 5b, 5c extending axially from the radially outer periphery of the radial portion 4. The free ends of the studs 5b are fixed to the plate of FIG. reaction, for example by riveting or screwing, with holes 6b formed in the studs 5b. The cover 2 comprises for example six fixing studs 5b. The axis of each hole 6b is parallel to the axis of rotation X of the mechanism 1.

The lid 2 also comprises three centering pins 5a distributed at 120 ° and fitted on pins (not shown) of the reaction plate with holes 6a.

The lid 2 is made of cast iron, for example cast aluminum alloy or carbon alloy cast iron, and is made by molding.

The pressure plate 3 is housed radially inside the pads 5a, 5b, 5c.

A diaphragm 7 is mounted radially inside the pads 5, said diaphragm 7 having a deformable annular portion 8, in the manner of a Belleville washer, from which actuating fingers 9 extend radially towards the inside. The radially inner periphery of the fingers 9 is adapted to cooperate with a clutch abutment, as is known per se. The diaphragm 7 is mounted bearing on the cover 2, at the level of bearing zones 10 formed on a sheet 10 'integral with the cover 2 (FIG. 1), and is held in abutment on the said zones 10 by means of hooks 11 which are fixed to the cover 2 by means of rivets 12. The rivets 12 also secure the sheet 10 'to the cover 2.

The diaphragm 7 serves to actuate the pressure plate 3 between a fully engaged position in which said pressure plate 3 is pushed towards the reaction plate, so as to grip the friction disk between said plates, and a position disengaged in said pressure plate 3 is moved away from the reaction plate so as to release the friction disc. For this purpose, resilient tongues 13 able to exert an axial force connect the lid 2 and the pressure plate 3. The tongues 13 are arranged to resiliently bias the pressure plate 3 towards its disengaged position.

Wear compensating means are interposed axially between the pressure plate 3 and the diaphragm 7. More particularly, the diaphragm 7 cooperates with said wear compensating means in an area located radially outwardly of the zones. support 10 of said diaphragm 7 on the lid 2.

These means comprise a mobile retraction member 14 in the form of a ring and having an end 15 against which the diaphragm 7 is able to come into abutment, and an end comprising at least one ramp 16 extending circumferentially, cooperating with an associated counter ramp 17 formed directly on the pressure plate 3.

By way of example, the angle of each ramp 16 of the catch member and the associated counter ramp 17 of the pressure plate 3 is between 2 and 12 °.

The catch member 14 comprises a toothed sector 18 forming a circumferentially extending rack, adapted to cooperate with displacement means so as to be rotated about the axis X, in case of wear of the friction disk. .

The displacement means comprise a worm 19 held in mesh with the rack 18. The worm 19 is rotatably coupled to a ratchet wheel 20 cooperating with a pawl 21 having an actuating tab 22 whose free end engages with the ratchet wheel 20 and whose actuation of the free end is caused by the wear of the friction disc.

The position of the ratchet wheel 20 with respect to said free end of the tab 22 of the pawl 21 varies as a function of the wear of the friction disc and the position of the pressure plate 3, so that the pawl 21 is able to drive the ratchet wheel 20, in case of wear of the friction disc, by displacement of the pressure plate 3 between its engaged and disengaged positions, as is known in itself. The rotation of the ratchet wheel 20 thus causes the rotational movement of the catch member 14 and therefore a change in the axial distance between the bearing zone 15 and the pressure plate 3, due to the presence of the ramp 16 and against the ramp 17. This variation in distance makes it possible to compensate the wear of the friction disk when necessary.

The ratchet wheel 20 and the worm 19 are pivotally mounted about an axis 23, the assembly being housed in a cassette 24. The cassette 24 is itself housed circumferentially between two studs of the lid 2. The cassette 24 is reported on the lid 2.

The cassette 24 comprises a base 26 of generally rectangular shape, extending in the horizontal plane and having two longitudinal edges 27, 28, respectively a radially inner longitudinal edge 27 and a radially outer longitudinal edge 28, and two lateral edges 29, flanks 30 extending in the axial direction from each of the side edges 29 of the base 26.

The base 26 further comprises a recess 31 formed opposite the worm 19, the worm 19 extending partially into said recess 31.

Each flank 30 has a hole 32 for passing the axis 23 with clearance. The axis 23 is thus not supported by the flanks of the cassette 24, but by the cover 2. A positioning tab 33 extends from each side. Each lug 33 has in particular a first portion extending in the direction of the corresponding lateral edge and connected to said sidewall 30, and a second part folded perpendicular to the first part, parallel to the base 26.

Note that the base 26 has a radially inner portion and a radially outer portion axially offset from each other connected by a cambered area. These two parts could however be located in the same axial plane.

The toothed sector 18 is interposed axially between the base 26 and the positioning tabs 33, so as to keep the toothed sector 18 and the catch member 14 axially in position.

Furthermore, the base 26 is able to bear on the free end of the stud 5c, so as to limit the rotation of the cassette 24 relative to the lid 2, about the axis 23.

The worm 19 may be able to bear on one of the flanks 30, possibly via a ring serving to limit friction, the ratchet wheel 20 bearing axially and rotatably coupled to the worm 19. An elastic member 34, here a helical compression spring, is mounted between the opposite flank and the ratchet wheel 20. The elastic member 34 exerts a preload of the ratchet wheel 20 and one of the flanks 10 of the cassette 24.

The pawl 21 is fixed to the cover 2, in the internal volume of said cover 2, by means of the rivet 12. A window or a recess 35 (FIG. 1) can be formed in the cover 2, so as to allow the movement of the ratchet 21, as is known per se.

The cassette 24 is mounted on the lid 2 so that the ends of the pin 23 are engaged in holes 40a, 40b formed in the studs of the lid 2. The hole 40a is opening and passes right through the stud 5a in the circumferential direction. The hole 40b opens on one side of the stud 5b and in the hole 6b.

The axis 23 comprises a hexagonal head 41 supported by means of a washer or an enlarged zone 42 on a bottom surface 43 of a countersink formed in the stud 5a, and a threaded end 44, opposite to the head 41. The axis 23 thus forms a screw. The threaded end 44 is screwed into a tapping hole 40b.

The threaded portion 44 can be held by a threadlock in the threaded portion of the stud 5b. Alternatively, the maintenance can be provided by a suitable tightening torque.

The axis 23 is thus held in position in the lid 2.

FIG. 4 illustrates a second embodiment, which differs from that described above with reference to FIGS. 1 to 3 in that the hole 40b can be blind, the hole 40a having a threaded portion cooperating with a threaded portion 44 of the axis 23. Thus, in this embodiment, the threaded portion 44 of the axis 23 is located near the head 41 and not at the end of the axis 23 which is opposite to the head 41.

FIG. 5 illustrates a third embodiment which differs from that described above with reference to FIGS. 1 to 3 in that the head 41 of the axis 23 is embedded in the hole 40a, in the manner of a screw HC.

FIG. 6 illustrates a fourth embodiment which differs from that described above with reference to FIGS. 1 to 3 in that the threaded portion 44 of the axis 23 cooperates with a nut 46 engaged in the hole 6b of the corresponding stud 5b. The hole 40b is then devoid of threaded portion.

FIG. 7 illustrates a fifth embodiment, which differs from those previously described in that the cover 2 comprises a hollow zone comprising a first flank 47a and a second flank 47b. The flanks 47a, 47b extend axially and are connected by a wall 48 extending circumferentially between said flanks 47a, 47b. The cassette 24 is mounted circumferentially between the flanks 47a, 47b, the axis 23 passing through holes formed in the flanks 47a, 47b of the cover 2. Such a cover 2 is for example made of steel, by stamping a sheet.

The shaft 23 comprises a head 41 at one end, resting on the side 47a by means of a washer or an enlarged zone 42, and a second threaded end 44, cooperating with a nut 46 resting on the flank 47b.

Figures 8 and 9 illustrate a sixth embodiment, which differs from those previously described in that the axis 23 has a first end engaged in the hole 40a and a second end engaged in the hole 40b. The second end has a threaded portion 44 screwed into a threaded portion of the hole 40b. The first end has a breakable portion 49 connected to the rest of the axis 23 by a ruptible zone 50. The ruptible zone 50 is designed to break when the tightening torque applied to the breakable portion 49 is greater than a determined torque. This torque value is variable and depends on the thread diameter of the threaded portion 44. This value may for example be between 2 N.m and 15 Nm in the case where the thread diameter is between 3 and 5 mm. The ruptible zone 50 is for example formed by a material restriction zone.

Thus during assembly, the axis 23 is engaged in the holes 40a, 40b and screwed by means of the head 41, for example of hexagonal shape, of the breakable part 49. Such screwing is achieved by cooperation of the part threaded 44 and the corresponding threaded portion of the hole 40b. The operator applies the aforementioned tightening torque so as to break the ruptible area 50. The breakable portion 49 can then be removed from the hole 40a. Subsequent disassembly of the axis 23 is no longer allowed. This is therefore maintained in the holes 40a, 40b of the cover 2.

Figure 10 illustrates a seventh embodiment, which differs from that discussed with reference to Figures 8 and 9 in that the axis 23 is smooth, i.e. is devoid of threaded portion. This is engaged in the hole 40a which is opening and passes through the stud 5a, and in the hole 40b which is one-eyed. A retaining screw 51 is screwed into a tapping hole 40a so as to maintain the axis 23 in the holes 40a, 40b of the cover 2. Indeed, the displacement of the axis 23 is limited, at a first end, by the end of the holding screw 51, and at a second end, by the bottom of the blind hole 40b. The shaft 23 is thus retained to the lid 2 by screwing. The holding screw 51 is separate from the axis 23. The holding screw 51 is coaxial with the axis 23.

FIG. 11 illustrates an eighth embodiment which differs from those previously described in that the hole 40a is blind, the hole 40b being opening and passing through the stud 5b. The axis 23 is devoid of threaded zone and is engaged in the holes 40a, 40b of the lid 2b. The axis 23 is held in position by one of the fixing screws 52 engaged in a tapping hole 6b. The fixing screw 52 allows the cover 2 to be fixed to the reaction plate 2a. The displacement of the axis 23 is thus limited, at a first end, by the bottom of the blind hole 40a, and at a second end, by the end of the screw 52. The axis 23 is thus retained to the lid 2 by screwing. The screw 52 is distinct from the axis 23.

Claims (11)

Clutch mechanism (1), in particular for a motor vehicle, comprising: a cover (2), a pressure plate (3) movable relative to the cover (2) along an axis of the mechanism, a diaphragm (12) movable between an engaged position and a disengaged position, able to actuate the movement of the plate of pressure (3), wear compensating means interposed between the diaphragm (12) and the pressure plate (3), said catching means comprising ramp means (14, 16) cooperating with counter-ramp means (3, 17) so that the rotation of the ramp means relative to the counter-ramp means changes the distance between the diaphragm (12) and the pressure plate (3), and means for rotating the ramp means, housed at least partly in a cassette (24) and mounted at least partly around an axis (23), said axis (23) being mounted in the cassette (24) and being supported by the cover ( 2), characterized in that the axis (23) is retained or fixed to the cover (2) by screwing. 2. Mechanism according to claim 1, characterized in that the axis (23) comprises a threaded portion (44), screwed into a threaded portion of the cover (2). 3. Mechanism according to claim 1, characterized in that the axis (23) comprises a threaded portion (44), cooperating with a nut (46) fixed relative to the lid (2). 4. Mechanism according to claim 3, characterized in that the nut is housed in a hole or a recess of the lid. 5. Mechanism according to one of claims 2 to 4, characterized in that the axis (23) forms a screw and comprises a head (41) resting on a surface of the lid (2) or housed in the corresponding hole (40a) of the lid (2). 6. Mechanism according to claim 1, characterized in that the axis (23) is housed in at least one hole (40a, 40b) of the cover (2), the axis (23) being immobilized in said hole (40a, 40b) of the cover (2) by a screw (51) engaged in a threaded portion of the cover (2), or by a screw (52) engaged in a hole (6b) of the cover (2) whose axis is parallel to the axis of rotation (X) of the clutch mechanism (1). 7. Mechanism (1) according to one of claims 1 to 6, characterized in that the cassette (24) comprises a base (26) having two side edges (29) from which extend two side flanks (30). , the axis (23) of the cassette (24) passing through the lateral flanks (30). 8. Mechanism (1) according to one of claims 1 to 7, characterized in that the lid (2) is obtained by molding cast aluminum alloy or carbon alloy cast iron. 9. Mechanism according to one of claims 1 to 8, characterized in that the cover comprises two pads (5a, 5b), each end of the axis (23) being engaged in one of the pads (5a, 5b). cover (5). 10. Mechanism according to one of claims 1 to 9, characterized in that the displacement means comprises a ratchet wheel (20) pivotable about the axis (23), a worm (19) coupled in ratchet rotation (20), the worm (19) meshing with a toothing (18) of the ramp means (14), and a pawl (21) having a body attached to the cover (2) and a pawl of actuating (22) cooperating with the ratchet wheel (20) to actuate the pivoting of the ratchet wheel (20) in case of wear, the rotation of said ratchet wheel (20) causing the moving of the ramp means (14) to compensate for wear. 11. Device comprising a clutch mechanism (1) according to one of claims 1 to 10, characterized in that it comprises a reaction plate, the friction disk being adapted to be clamped between the pressure plate (3). ) and the reaction plate in the engaged position and released in the disengaged position, the cover (2) being fixed relative to the reaction plate.