WO2012049383A1

WO2012049383A1 - Wedge-type actuating device for motor vehicle clutch system

Info

Publication number: WO2012049383A1
Application number: PCT/FR2011/051926
Authority: WO
Inventors: Gilles Lebas; Thibaut Laforge
Original assignee: Valeo Embrayages
Priority date: 2010-10-14
Filing date: 2011-08-17
Publication date: 2012-04-19
Also published as: FR2966216B1; FR2966216A1

Abstract

The invention relates to an actuating device (10) for a motor vehicle friction clutch system, which comprises: a moving wedge (36) for actuating the clutch system, the wedge (36) being able to move between an extreme upper rest position and an extreme lower position in which it actuates the clutch system; - a vertical push rod (50) able to move vertically to push the wedge (36) from its rest position (P2) into its actuating position; characterized in that the push rod (50) can be connected temporarily to the wedge (36) by means (60, 62) of temporary connection which are operated between a locked state in which the push rod (50) moves as one in longitudinal displacement in both directions with the wedge (36), and a released state in which the push rod (50) can slide vertically upwards without the wedge (36) accompanying it.

Description

"Wedge actuator for a motor vehicle clutch system"

The invention relates to an actuating device for a friction clutch system, particularly a motor vehicle, which comprises:

- A movable wedge which is adapted to exert a longitudinal force of actuation of the clutch system, the wedge being movable along a vertical actuating stroke between an upper end position of rest of the clutch system to which it is resiliently biased, and a lower extreme position of actuation of the clutch system;

- A vertical push rod movable vertically at least between an upper position of docking with the corner and a lower extreme position of urging to push the wedge from its rest position to its actuated position.

The friction clutches generally comprise a pressure plate which is intended to be clamped longitudinally against a reaction plate with the interposition of a friction disc in order to couple a driven shaft with a driving shaft, the clutch then being in a state engaged.

When the pressure plate is moved away from the reaction plate, the friction disk is no longer in contact with any of the plates. The driven shaft is decoupled from the drive shaft, the clutch then being in a disengaged state.

Clamping of the pressure plate is effected by the longitudinal sliding of an actuating stop. The position of the actuating stop is controlled by an actuator via a pivoting lever.

Such clutches may be of the type called "normally closed" or of the type called "normally open.

In the case of clutches of the "normally closed" type, the pressure plate is resiliently biased towards a clamping position against the reaction plate so that the clutch system is in its engaged state. The actuating stop is then in an extreme rear position of rest. To control the clutch system to its disengaged state, it is necessary to slide the actuating stop longitudinally forward to an extreme position before actuation against the elastic return force of the reaction plate.

Conversely, in the case of clutch systems of the type

"Normally open", the pressure plate is resiliently biased to a position away from the reaction plate so that the clutch system is in a disengaged state. The actuating stop is then in its rear rest position. To control the clutch system to its engaged state, it is necessary to slide the actuating stop longitudinally forward to an actuating position against the elastic return force of the reaction plate.

In the rest of the description and in the claims, it will therefore be understood that the actuating position of the actuating stop may, depending on the case, correspond to a disengaged state for a clutch system of the "normally closed" type or in an engaged condition for a clutch system of the "normally open" type.

The control lever is generally biased by the free end of a push rod which extends in a direction generally orthogonal to the lever arm.

However, the space allocated by car manufacturers for mounting a clutch system sometimes has dimensions or shapes that are not compatible with known actuators.

To solve this problem, it has already been proposed to control the movements of the stop by means of a sliding wedge parallel to the arm of the operating lever. The lever push rod is thus arranged parallel to the lever arm, which reduces the size.

The wedge is generally returned to its rest position by the elastic return of the actuating stop to its rest position. Thus, the push rod is in principle only to push the corner to its actuating position. The push rod can thus be retracted along a second race located below the rest position of the wedge. This second stroke is for example used to actuate stroke retraction means that compensate for the axial displacement of the push rod resulting from the wear of the friction lining of the clutch.

However, because of the displacement of the wedge in a direction generally orthogonal to the longitudinal return force of the actuating abutment, it happens that the wedge is trapped in an intermediate position between its rest position and its actuating position. .

The invention proposes to solve this problem in particular.

Another object of the invention is to improve the means of catch-up adjustment in order to adapt them to this type of wedge-actuating device.

The actuating device according to the invention is characterized in that the push rod is capable of being temporarily connected to the wedge by temporary connection means controlled between a locked state in which the push rod is secured in longitudinal displacement in both directions with the wedge, and a released state in which the push rod is slidable vertically upward without causing the wedge.

According to other features of the invention:

the temporary connection means are means by interlocking between a first connecting element carried by the push rod and a second connecting element of complementary shape carried by the wedge, the connecting elements being movable relative to one another; another between a locking position corresponding to the locked state of the connecting means and a release position corresponding to the released state of the connecting means;

the temporary connection means are automatically controlled in their unlocked state when the corner occupies its extreme rest position; and in their locked state when the wedge is moved relative to its extreme rest position;

at least one of the connecting elements is mounted to move elastically between its locking position and its release position, so as to be resiliently biased towards one of these positions, while is forced towards the other of these positions by contact with a fixed ramp of the ispositif;

the element of the mobile unit is resiliently returned to its position of ligation;

the second element of the housing is mounted on one end with an elastically flexible vertical tongue which is carried by the corner, the end of the tongue being interposed between a face of the corner and the fixed ramp;

the device comprises means of compensating for the stroke which makes it possible to compensate for the axial displacement of the push rod which results from the wear of the friction linings of the clutch, the means of catch-up being capable of be actuated by sliding the push rod vertically upward beyond its docking position;

the racing catching means comprise:

an actuating element to which the push rod is moved by screwing means in such a way that the push rod and the actuating element are idle in vertical displacement in both directions, and in such a way as to allow adjustment of the vertical position of the push rod relative to the actuating element by screwing;

an external toothing which is sol idaire in vertical displacement of the actuating element, the external toothing being sol idid in rotation with the push rod;

two fixed internal teeth for unidirectional drive of the external toothing of the push rod for adjusting the vertical position of the push rod by screwing in one direction or the other of the push rod relative to the actuating element;

the external toothing is carried by an adjustment ring which is arranged around the push rod, the adjustment ring being immobilized vertically upwards against an abutment face of the actuating element, and towards the down by means of ground idarization in vertical displacement downwards. - The adjustment ring is secured in vertical displacement with the actuating element via a pulling ring which has an upper locking face which abuts downwardly against a vis-à-vis face. screw of the actuating element, a lower locking face which abuts against a face vis-à-vis the adjusting ring, and a vertical rigid connecting body of the two locking faces of the locking ring. draw;

- The body of the pull ring is interposed radially between the push rod and the adjusting ring;

- The body of the pull ring is interposed radially between the adjusting ring and the internal teeth;

- The body of the pull ring is arranged externally with respect to the internal teeth.

Other characteristics and advantages will become apparent on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings among which:

- Figure 1 is a perspective view showing a wedge clutch actuator made according to the teachings of the invention;

- Figure 2 is a side view which shows the device of Figure 1;

- Figures 3 to 7 are side views which show schematically the connection between the push rod and the corner of the device of Figures 1 and 2 in different phases of operation;

- Figure 8 is a view similar to those of Figures 3 to 7 which shows an alternative embodiment of the invention;

- Figure 9 is a transverse vertical sectional view which schematically shows the means of catching stroke between the push rod and an actuating element of the device of Figures 1 and 2;

FIG. 10 is a perspective view showing the stroke-catching means of FIG. 9 in which the thrust rod provided with an adjusting ring and means for securing the adjusting ring with the actuating element;

- Figures 1 1 and 12 are views similar to that of Figure 9 which respectively represent a first and a second embodiment of the invention.

In the remainder of the description and in the claims, the following will be adopted in a nonlimiting manner: longitudinal directions, oriented from back to front, vertical, oriented from bottom to top, and transverse, oriented from left to right indicated by the "L" trihedron. , V, T "of the figures. In order to facilitate understanding of the description, the vertical direction is chosen to be parallel to the axis of the push rod regardless of the direction of Earth's gravity.

In the following description, like reference numerals denote like parts or having similar functions.

FIG. 1 shows an actuating device 10 of a friction clutch system (not shown) of a motor vehicle which is intended to couple a motor shaft with at least one driven shaft. The motor shaft and the driven shaft are rotatable about a same longitudinal axis of rotation "A". Conventionally, the driven shaft is connected to a rear gearbox (not shown).

The clutch system is intended to be controlled by an actuating device 10 which is shown in FIG.

The actuating device 10 comprises an annular actuating stopper 12 of the clutch system which is slidably mounted longitudinally with respect to a fixed casing of the clutch system on a clutch stroke which is delimited by an extreme position before the clutch. actuation in which it actuates the clutch system against an elastic return force "F1", and an extreme rear position of rest towards which the actuating stopper 12 is resiliently biased by said elastic return force "F1"". As shown in Figure 2, the elastic return force "F1" is applied to the actuating abutment 12 in a longitudinally oriented direction towards the rear, for example by a diaphragm. The actuating abutment 12 is here formed by a rolling bearing which is slidably mounted around a longitudinal guide tube 14 of longitudinal axis "A". The actuating abutment 12 comprises a first ring carrying a face 16 before biasing the diaphragm, and a second ring carrying a flange 17 radially outside. Such an actuating stop 12 is well known and will not be described in more detail.

The actuating device 10 also comprises an actuator 18 which is intended to control the sliding of the actuating abutment 12 by means of a rigid control lever 20.

The control lever 20 extends along a principal axis "B" globally vertical. It comprises a first section 22 of upper end forming a bar. The control lever 20 also has a second lower end section 24 divided into two branches 26 forming a fork "U" open vertically downward. Because of this particular shape, such a control lever 20 is commonly referred to as a "fork".

The upper end 28 of the control lever 20 is articulated on a member (not shown) fixed relative to the gearbox housing of the motor vehicle. The control lever 20 is in particular mounted pivotally pivoted about a transverse axis of pivoting "C" through a hinge (not shown).

Said articulation is advantageously a ball joint which also allows an angular travel of the control lever 20 around its main axis "B". The control lever 20 is thus capable of pivoting "in roll" around its main axis "B" to compensate for tolerances and mounting clearances of the actuating stop 12 and the diaphragm.

As can be seen in FIG. 2, the control lever 20 is mounted so that the branches 26 of the fork 24 embrace transversely the actuating abutment 12 longitudinally behind the flange 17. Thus, the lower end free of each branch 26 is arranged vis-à-vis the rear face of the flange 17. The two free lower ends of the branches 26 are more particularly arranged diametrically opposite to the axis "A" of rotation of the clutch system. The free ends thus form a point of thrust 30 of the actuating abutment 12 via the collar 17.

The actuator 18 is capable of exerting an orthogonal actuating force to the second lever arm, here a longitudinal force, at a biasing point 34 of the control lever 20 to cause the pivoting of the control lever 20 around its axis. pivoting "C" so as to push the actuating abutment 12 longitudinally forwardly by leverage against the elastic return force "F1".

The biasing point 34 occupies a fixed position on the control lever 20 and is offset vertically with respect to the thrust point 30. The biasing point 34 is here arranged between the pivot axis "C" and the thrust point 30 of the control lever 20. The control lever 20 thus forms a so-called "third kind" lever.

In this configuration, the control lever 20 has two lever arms. A first fixed length lever arm is defined as a straight line connecting the pivot axis "C" with the free lower end 30 of the legs 26. The second fixed length lever arm is defined as a straight line connects the pivot axis "C" to the point of stress 34.

The biasing point 34 is here globally aligned vertically with the pivot axis "C" and the thrust point 30. The two lever arms thus extend in the same vertical longitudinal plane.

According to a not shown variant of the invention, the control lever can also be a lever of the first kind, in which the hinge is interposed between the push point and the biasing point. The control lever may also be a lever of the second kind, in which the point of thrust is interposed between the articulation and the point of stress.

In the embodiment shown in the figures, the control lever 20 extends along a generally straight main axis "B". Alternatively, the control lever 20 has a shape bent or curved in a longitudinal vertical plane. In this case, the first lever arm can form an angle with the second lever arm.

As shown in FIG. 2, the actuator 18 comprises a movable wedge 36 whose front face forms a cam track 38. The cam path 38 is arranged in sliding contact with the biasing point 34 of the control lever 20 the biasing point 34 thus forming a cam follower.

By the term "sliding", it will be understood that the contact can be made either by friction or by rolling of the biasing point 34 on the cam path 38 of the wedge 36.

The wedge 36 has a prismatic shape delimited longitudinally rearwards by a transverse vertical rear face 40 and forwardly by the cam path 38. The wedge 36 is further delimited upwards by an upper face 41.

As shown in Figure 2, the wedge 36 is movably mounted along an actuating stroke which extends in a fixed transverse plane, said transverse plane being generally parallel to the second lever arm. In the examples shown, the wedge 36 is more particularly slidably mounted along a vertical rectilinear race which extends parallel to the second lever arm. The wedge 36 is thus slidably mounted between:

an extreme upper rest position corresponding to the extreme rear rest position of the actuating stopper 12 and in which the upper face 41 of the wedge 36 abuts against a fixed face 54 of the actuator 18; and

- A lower actuating position in which the actuating stop 12 is in its extreme position before actuation.

The wedge 36 is thus able to exert the longitudinal force of actuation on the lever 20 to actuate the clutch system.

The cam path 38 here has a plane slope which is inclined relative to a transverse vertical plane. The inclination of the slope is such that the lower vertical end of the wedge 36 is less thick, in the longitudinal direction, than its upper vertical face 41. Sliding between the biasing point 34 and the cam path 38 is here made by rolling. For this purpose, the control lever 20 comprises a roller 42 which is rotatably mounted about a transverse axis at the point of stress 34. The roller 42 thus forms the point of stress 34 of the control lever 20.

The wedge 36 is designed and arranged so that the rolling roller 42 is in permanent contact with the cam path 38 regardless of the position of the wedge 36 along its actuating stroke.

In a nonlimiting manner, the cam path 38 has a rectilinear profile so that the pivoting of the control lever 20 is linearly proportional to the sliding path of the wedge 36.

In general, it is possible to define the profile of the cam path 38 as a function of the actuating force to be applied to the wedge 36 to pivot the control lever 20 and as a function of the length of the stroke of the cam. actuation.

As represented in FIG. 2, the elastic return force "F1" is reflected by the control lever 20 on the wedge 36 perpendicularly to the cam path 38. Due to the slope formed by the cam path 38, the elastic return force "F1" is divided into two components.

A first vertical component "F1 v" of the elastic return force in projection on a vertical axis acts on the wedge 36 to slide vertically upwards. During normal operation, the wedge 36 is thus resiliently returned to its extreme rest position by the elastic return force.

A second longitudinal component "F1 I" of the elastic return force "F1" projection on a longitudinal axis pushes the wedge 36 longitudinally rearwardly. This second longitudinal force "F1 I" is intended to be transmitted to a fixed element. For this purpose, the wedge 36 is constantly in longitudinal support rearward against a transverse vertical bottom 44 of reaction. The bottom 44 is fixed relative to the gearbox of the motor vehicle. It is here formed by a plate which is fixed to the housing of the gearbox. The bottom 44 is for example made in a stamped sheet having stiffeners, or a forged part or a molded part.

According to a not shown variant of the invention, the bottom 44 is formed directly by a transverse vertical wall of the gearbox of the motor vehicle.

To allow the sliding of the wedge 36 relative to the bottom 44, the wedge 36 comprises rollers 46. The wedge 36 is thus rolled along a track formed on the bottom 44. Advantageously, the bottom 44 is provided with rails of longitudinal guides (not shown) which line the track vertically so as to prevent the corner 36 from leaving the track.

As shown in Figure 2, the actuator 18 also comprises a casing 54 carrying an electric motor 56 which is capable of moving a movable member guided in translation in the housing 54 in a vertical direction. This moving element acts via a push rod 50 on the sliding of the wedge 36.

As shown in more detail in FIG. 3, the push rod 50 has a vertical axis, and it is delimited downwards by a free lower end section 64. The push rod 50 also comprises a lower face 51 of abutment which is capable of being brought into abutment vertically downwards against the upper face 41 of the wedge 36 to push the wedge 36 towards its extreme operating position. The abutment face 51 is here formed by a shoulder face which delimits vertically upward the free lower end section 64 of the push rod 50.

The upper face 41 of the wedge 36 has a housing 68 which is open upwards and backwards. The lower free end section 64 of the push rod 50 can be inserted vertically into the housing 68 when the abutment face 51 of the push rod 50 abuts against the upper face 41 of the wedge 36.

As shown in FIG. 3, the wedge 36 is intended to be pushed vertically downwards by the vertical thrust rod 50 against the vertical component "F1v" of the elastic return force "F1" of the diaphragm. The push rod 50 thus extends generally parallel to the second lever arm of the control lever 20.

The moving element, which is better seen in FIG. 2, comprises a sliding actuating element 58 which is driven by the electric motor 56. The push rod 50 is integral in vertical displacement in both directions with the element The thrust rod 50 is more particularly connected to the actuating element 58 by an upper end section of the thrust rod 50.

The actuating element 58 is here connected to the push rod 50 by means of catch-up stroke which will be detailed later. These stroke-compensating means make it possible to compensate for the axial displacement of the thrust rod 50 which results from the wear of the friction linings of the clutch. The stroke-catching means make it possible to adjust the vertical position of the abutment face 51 of the thrust rod 50 with respect to the actuating element 58.

The actuating element 58 and the push rod 50 are thus able to slide in the housing 54 in a total sliding stroke which is longer than the actuating stroke of the wedge 36. The total sliding stroke of the Actuating element 58 and push rod 50 thus have a first adjustment stroke and a second actuating stroke.

The first adjustment stroke "P0-P1" is delimited:

upwardly by an upper extreme adjustment position "P0" which is represented in FIG. 3 and in which the abutment face 51 of the push rod 50 is spaced from the upper face 41 of the wedge 36; and

downwards by an intermediate docking position "P1" which is indicated in FIG. 4, and in which the abutment face 51 of the push rod 50 is in contact with the upper face 41 of the wedge 36, the wedge 36 being in its rest position.

The second actuation stroke "P1 -P2" is delimited:

upwardly by said intermediate docking position "P1"; and downwardly by a lower biasing position "P2" which is shown in FIG. 5, and in which the wedge 36 is pushed into its extreme operating position.

The references "PO, P1, P2" of the figures more particularly indicate the position of the stop face 51 of the push rod 50 with respect to the casing 54.

The actuating stroke "P1-P2" of the actuating element 58 corresponds to the displacement of the push rod 50 for the opening and closing of the clutch. Along this actuating stroke "P1-P2", the abutment face 51 of the push rod 50 bears against the upper face 41 of the wedge 36.

When the push rod 50 moves along its first adjustment stroke "P0-P1", the wedge 36 is normally in its upper rest position in which it is in vertical abutment against the housing 54 of the actuator 18. Thus, the abutment face 51 of the push rod 50 is spaced from the corner 36 vertically upwards.

However, it has been found that a simple connection by plane support of the push rod 50 on the upper face 41 of the wedge 36 is likely to create problems when returning the wedge 36 to its rest position. Indeed, when the push rod 50 returns to its upper docking position, the wedge 36 is returned to its rest position only by first vertical component "F1 v" of the elastic return force. However, it can happen that the corner 36 is stuck before being returned to its rest position. This is particularly the case when the sliding of the wedge 36 is done with friction. The push rod 50 then slides towards its docking position "P1" leaving the wedge 36 wedged in an intermediate position.

To solve this problem, the invention proposes that the push rod 50 is capable of being temporarily connected to the wedge 36 along the actuating stroke "P1-P2" of the push rod 50. For this purpose, the push rod 50 and the wedge 36 are equipped with temporary connection means which are controlled between: a locked state in which the push rod 50 is integral with the wedge 36 in vertical displacement in both directions; and

- A released state in which the push rod 50 is slidable along its adjustment path "P0-P1" without causing the wedge 36.

The temporary connection means are here means by elastic interlocking between a first connecting element 60 carried by the push rod 50 and a second connecting element 62 of complementary shape carried by the wedge 36. The two connecting elements 60, 62 are capable of being nested one inside the other in a direction orthogonal to the vertical axis of the push rod 50. Thus, when they are nested, an upper face of the first connecting element 60 is arranged vertically against a lower face of the second connecting element 62 so that the push rod 50 is able to pull the wedge 36 upwards.

The nesting is done automatically when the push rod 50 pushes the wedge 36 towards its extreme operating position.

As shown in FIGS. 3 to 7, the first connecting element 60 is a female element which is formed by a notch formed in a rear face of the free lower end section 64 of the push rod 50.

The second connecting element 62 is a male element which is formed by a longitudinal lug. This second connecting element 62 is carried by a longitudinal tongue 66 which is fixed under the rear face 40 of the wedge 36. The tongue 66 has a first lower fastening end 67 to the rear face 40 of the wedge 36, and a second upper end. 69. The second connecting element 62 extends projecting longitudinally forwards from the upper free end 69 of the tongue 66.

The interlocking of the second connecting element 62 in the first connecting element 60 is made with a vertical clearance to facilitate the interlocking and disengagement movements between the two connecting elements 60, 62. In addition, the upper free end 69 of the tongue 66 is arranged longitudinally overboard on the housing 68 which opens in the rear face 40 of the wedge 36, so that the second connecting element 62 is arranged vis-à-vis the first connecting element 60 when the lower free end section 64 of the push rod 50 is inserted into the housing 68, that is to say when the abutment face 51 of the push rod 50 is abutting against the upper face 41 of the corner 36.

The tongue 66 is made of an elastic material so as to be elastically flexible between:

a locking position which is represented in FIG. 5 and in which the second connecting element 62 is fitted into the first connecting element 60 inside the housing 68, this position corresponding to the locked state of the connecting means temporary; and

- A release position which is shown in Figures 4 and 6 and wherein the second connecting member 62 is moved longitudinally rearwardly out of the housing 68 so as to allow the insertion or withdrawal of the push rod 50 relative to the housing 68 of the corner 36, this position corresponding to the released state of the locking means.

The temporary link means can be automatically controlled:

- In their released state when the wedge 36 is in its extreme rest position, as shown in Figures 3, 4 and 6;

in their locked state when the wedge 36 is displaced with respect to its extreme rest position, as represented in FIG.

For this purpose, at least one of the connecting elements 60, 62 is mounted elastically movable between its locking position and its release position, so as to be resiliently biased towards one of these positions, while it is constrained to the other of these positions by contact with a fixed ramp 70 of the device.

In the example shown in FIGS. 3 to 7, the tongue 66 is resiliently biased towards its release position in which the free end 69 of the tongue 66 is spaced longitudinally rearward with respect to the rear face 40 of the wedge 36 , towards the bottom 44. The upper free end 69 of the tongue 66 is slidable along a fixed ramp 70 which is arranged against the fixed bottom 44 opposite the free upper end 69 of the tongue 66. 70 extends projecting longitudinally forwards with respect to the bottom 44. The upper free end 69 of the tongue 66 is thus interposed between the rear face 40 of the wedge 36 and the fixed ramp 70.

The ramp 70 extends along the path of the upper free end 69 of the tongue 66 when the wedge 36 travels its actuating stroke "P1-P2". The ramp 70 is shaped so as to bend the tongue 66 towards its locking position against the elastic return force as the wedge 36 is engaged on its actuating stroke "P1-P2".

In practice, the tongue 66 is biased towards its release position a little before the wedge 36 is in its extreme rest position, so as to ensure the release of the push rod 50. This distance traveled by the wedge 36 in the unlocked state of the connecting means is advantageously a very short dead stroke which does not influence the state of the clutch.

According to a variant of the invention which is shown in Figure 8, the tongue 66 is elastically biased towards its locking position. In this case, the fixed ramp 70 is arranged to constrain the tongue 66 to its release position when the wedge 36 travels its dead path towards its rest position. The ramp 70 is here arranged vertically opposite the free upper end 69 of the tongue 66 so that the tongue 66 comes into contact with the ramp 70 via its free upper end 69. upper end 69 of the tongue 66 is bent so as to promote its sliding against the ramp 70.

In operation of the controller 10, as shown in FIG. 3, the push rod 50 is retracted vertically upwardly relative to the wedge 36. The wedge 36 is in its rest position.

When the actuator 18 is controlled so as to actuate the clutch system, the push rod 50 slides vertically towards the down to its docking position "P1", as shown in Figure 4. The tab 66 then occupies its release position.

Then the push rod 50 pushes vertically down the wedge 36. The push rod 50 then moves solidly with the wedge 36. The upper end 69 of the tongue 66 then slides on the ramp 70, causing it to sag elastic to its locking position. The second connecting element 62 is then fitted longitudinally forwards in the first connecting element 60. The push rod 50 is then secured in vertical displacement in both directions with the wedge 36.

When the wedge 36 is controlled to its rest position, the push rod 50 is controlled vertically upwardly. The wedge 36 is itself resiliently biased towards its rest position by the vertical component "F1 v" of the elastic return force "F1".

In the event of jamming of the wedge 36, as represented in FIG. 5, the push rod 50 assists the elastic return force "F1" by pulling the wedge 36 towards its rest position by means of the temporary connection means 60 , 62 in their locked state.

When the wedge 36 comes close to its rest position, the upper free end 69 of the tongue 66 is no longer constrained by the ramp 70, as shown in FIG. 6. The tongue 66 is then returned to its position of release. The push rod 50 is then free to slide towards its upper extreme position without pulling on the wedge 36.

It may also happen that the second connecting element 62 remains locked in the first connecting element 60 because of the friction, as shown in FIG. 7. This can happen in particular when the push rod 50 has to pull strongly on the corner 36 to assist his return to his resting position. In order to avoid such a problem, when the push rod 50 has returned to its docking position "P1", it is again slidably controlled for a very short distance to its actuating position. This slight displacement makes it possible to restore sufficient vertical clearance between the contacting faces of the connecting elements 60, 62. The clearance thus allows the tongue 66 to be returned to its release position. The stroke-catching means are now described which enable the actuating element 58 to be adjustably connected to the push rod 50. This description is made with reference to FIGS. 9 and 10.

The race-catching means make it possible to compensate for the axial displacement of the push rod 50 which results from the wear of friction linings of the clutch. The catch-up means are capable of being actuated by sliding of the push rod 50 along its adjustment path "P0-P1".

As shown in FIG. 9, for its adjustable attachment to the actuating element 58, the push rod 50 is received in a downwardly-opening, vertical axis orifice 71 formed in the actuating element 58.

The section of the push rod 50 which is inserted into the orifice 71 is provided with an external thread 72 which is intended to be screwed into a tapping 74 of the actuating element 58. This screw connection makes it possible to ensure the vertical displacement secured in both directions of the push rod 50 with the actuating element 58.

In a variant, the actuating element comprises a threaded section which is screwed into a tapping of the push rod.

This screw connection also makes it possible to adjust the vertical position of the abutment face 51 of the push rod 50 by turning the push rod 50 about its axis in one direction or the other with respect to the pressure element. actuation 58.

The rotation of the push rod 50 is controlled by means of an adjusting ring 76 which is arranged around the push rod 50. The adjusting ring 76 is here arranged outside the opening 71 of the actuating element.

The adjusting ring 76 is locked in rotation relative to the push rod 50. Thus a rotation of the adjusting ring 76 causes a rotation of the push rod 50. The locking in rotation is for example achieved by press fitting. a section of the push rod 50 having a non-circular section in a central orifice of complementary shape of the adjusting ring 76. The locking in rotation can also be achieved by means of a pin or other known locking means.

The push rod 50 is free to slide vertically with respect to the adjusting ring 76.

In addition, the adjusting ring 76 is immobilized vertically with respect to the actuating element 58:

upwards against an abutment face 78 of the actuating element 58; and

downwards by means of securing in vertical displacement with the actuating element 58.

The securing means are formed by a pull ring 80 which comprises a sleeve 82 of vertical axis which is interposed radially between the adjusting ring 76 and the push rod 50. The pulling ring 80 also comprises a collar 84 of FIG. lower end and an upper end flange 86. Each flange 84, 86 extends radially outwardly with respect to the sleeve 82.

The lower flange 84 is arranged vertically under the adjusting ring 76 so that an upper locking face of the flange 84 is vertically abutting against a face facing the adjusting ring 76.

The upper flange 86 is arranged vertically above the adjusting ring 76, so as to be received in an annular groove 88 formed in the inner cylindrical wall of the orifice 71 of the actuating element 58. Thus, the upper flange 86 has a lower locking face which abuts against a face opposite the groove 88 of the actuating element 58. The adjustment ring 76 is thus capable of pulled upwards by the actuating element 58.

The sleeve 82 forms a vertical body which makes it possible to rigidly connect the two collars 84, 86 of the pull ring 80 between them.

The adjusting ring 76 is made of an elastically deformable material such as plastic to facilitate its mounting. Advantageously, as illustrated in Figure 10, an upper end portion of the sleeve 82 and the upper flange 86 has notches which open vertically upwards. The indentations circumferentially delimit vertical tabs 89 formed in the sleeve 82 and each tab 89 carries an upper flange portion 86. Thus, each tab 89 is capable of elastically deformed in flexion to facilitate the insertion of the upper flange 84 into throat 88.

As is more particularly visible in FIG. 9, the adjusting ring 76 has an external toothing 90 which is thus integral in vertical displacement with the actuating element 58. In addition, the external toothing 90 is integral in rotation with the thread 72 of the push rod 50.

The external toothing 90 is formed of lozenges distributed on its periphery. The external toothing 90 is intended to cooperate with the internal teeth 92 of two rings 94 unidirectional drive.

The one-way drive rings 94 are fixedly and coaxially mounted in the housing 54 so as to surround the actuating element 58. The adjusting ring 76 is slidable vertically within the drive rings 94 .

Each fixed internal toothing 92 is capable of cooperating with the external toothing 90 of the adjustment ring 76 to adjust the vertical position of the push rod 90 by screwing the thread 72 of the push rod 50 with respect to the thread 74 of the actuating element 58.

The principle of driving a ring by unidirectional drive rings is similar to that of already known devices. For a detailed explanation of the control in rotation of the adjusting ring 76, reference will be made to the document FR-A1 -2,901,587 or to the document US-A1 -2009 / 028,934. These documents describe a similar device in which the adjusting ring 76 is replaced by a nut.

According to a variant of the invention shown in Figure 1 1, the sleeve 82 of the pull ring 80 is interposed radially between the adjusting ring 76 and the internal teeth 92. In this case, the groove 88 is formed in an outer face of the actuating element 58, and the flanges 84, 86 extend radially inwards. The sleeve 82 then has openings to allow the passage of the external toothing 90.

According to another variant of the invention shown in Figure 12, the sleeve 82 of the pull ring 80 is arranged externally relative to the rings 94 of unidirectional drive.

The stroke retraction device made according to the teachings of the invention makes it possible to simplify the structure of the device by eliminating in particular the spring which was present in the devices of the state of the art. In addition, such a device is more reliable and less expensive to produce.

Claims

REVEN D ICATIONS

1. Actuating device (10) for a friction clutch system, particularly a motor vehicle, comprising:

- A wedge (36) movable which is adapted to exert a longitudinal force of actuation of the clutch system, the wedge (36) being movable along a vertical actuating stroke between an upper rest position of the system clutch to which it is resiliently biased, and a lower extreme position of actuation of the clutch system;

- a vertically movable vertical push rod (50) at least between an upper docking position (P1) with the wedge (36) and a lower biasing position (P2) for urging the wedge (36) from its position of rest (P2) to its actuating position;

characterized in that the push rod (50) is capable of being temporarily connected to the wedge (36) by means of temporary connection means (60, 62) controlled between a locked state in which the push rod (50) is secured in longitudinal displacement in both directions with the wedge (36), and a released state in which the push rod (50) is slidable vertically upwards without causing the wedge (36).

2. Device (10) according to the preceding claim, characterized in that the temporary connection means are means by interlocking between a first connecting element (60) carried by the push rod (50) and a second connecting element ( 62) of complementary shape carried by the wedge (36), the connecting elements (60, 62) being movable relative to each other between a locking position, corresponding to the locked state of the connecting means, and a release position corresponding to the released state of the link means.

3. Device (10) according to any one of the preceding claims, characterized in that the means (60, 62) of temporary connection are controlled automatically:

- in their unlocked state when the corner (36) occupies its extreme rest position; in their locked state when the wedge (36) is displaced with respect to its extreme rest position.

4. Device (10) according to the preceding claim, characterized in that at least one of the connecting elements (62) is mounted elastically movable between its locking position and its release position, so as to be resiliently biased towards one of these positions, while it is forced towards the other of these positions by contact with a fixed ramp (70) of the device (10).

5. Device (10) according to the preceding claim, characterized in that the movable connecting element (62) is resiliently biased towards its release position.

6. Device (10) according to any one of claims 4 or 5, characterized in that the second connecting element (62) is mounted on a free end (69) of a tongue (66) elastically flexible vertical which is carried by the wedge (36), the free end (69) of the tongue (66) being interposed between a face (40) of the wedge (36) and the fixed ramp (70).

7. Device (10) according to any one of the preceding claims, characterized in that it comprises means of compensating stroke that compensate for the axial displacement of the push rod (50) resulting from the wear of friction pads of the clutch, the race-catching means being capable of being actuated by sliding the thrust rod (50) vertically upwards beyond its docking position (P1).

8. Device (10) according to the preceding claim, characterized in that the catch-up means comprise:

an actuating element (58) to which the push rod (50) is connected by screw means (72, 74) so that the push rod (50) and the actuating element (58) are integral in vertical displacement in both directions, and so as to allow adjustment of the vertical position of the push rod (50) with respect to the actuating element (58) by screwing; - An external toothing (90) which is integral in vertical displacement of the actuating element (58), the external toothing (58) being integral in rotation with the push rod (50);

two fixed internal teeth (92) for unidirectional drive of the external toothing (90) of the push rod (50) for adjusting the vertical position of the push rod (50) by screwing in one direction or the other the push rod (50) with respect to the actuating element (58).

9. Device (10) according to the preceding claim, characterized in that the external toothing (90) is carried by an adjusting ring (76) which is arranged around the push rod (50), the adjusting ring ( 76) being immobilized vertically:

- upwards against a stop face of the actuating element

(58);

downwardly by means (80) for joining vertically downwardly.

10. Device (10) according to the preceding claim, characterized in that the adjusting ring (76) is secured in vertical displacement with the actuating element (58) via a pull ring (80). ) which includes :

- an upper locking face (86) which abuts against a face (88) vis-à-vis the actuating element (58);

- a lower locking face (84) which abuts against a face vis-à-vis the adjusting ring (76);

- A vertical body (82) rigid connection of the two locking faces (84, 8) of the pull ring (80).

1 1. Device (10) according to the preceding claim, characterized in that the body (82) of the pull ring (80) is interposed radially between the push rod (50) and the adjusting ring (76).

12. Device (10) according to claim 10, characterized in that the body (82) of the pull ring (80) is interposed radially between the adjusting ring (76) and the internal teeth (92).

13. Device (10) according to claim 10, characterized in that the body (82) of the pull ring (80) is arranged externally relative to the internal teeth (92).