FR2768787A1 - FRICTION CLUTCH - Google Patents

Abstract

The invention relates to a friction clutch comprising a cover (6), an annular spring (7) mounted so as to be able to pivot therein and urging a pressure plate (11), connected to the cover in a non-rotating manner but nevertheless with possibility of limited axial offset. To ensure forced retention of the pressure plate during a pivoting movement of the annular spring, provision is made between the annular spring and the pressure plate of the retaining stirrups (15) which, at least under the action of a centrifugal force, are connected by friction, (in 16b, 21) with a component (6) movable axially relative to the pressure plate (11).

Description

FRICTION CLUTCH

  The present invention relates to a friction clutch, in particular for vehicles, comprising a device which dampens the oscillations of the pressure plate, occurring in particular during the clutch and disengage processes, so that also unpleasant noises can be suppressed. In particular, the invention relates to a friction clutch comprising a casing and an annular spring, mounted so as to be able to pivot on the latter and which requests a pressure plate, connected to the casing without the possibility of relative rotation but nevertheless with the possibility of axial offset. limited, and o there is provided, for a forced retention of the pressure plate during a pivoting movement of the annular spring, des.étipers retaining between the annular spring and the pressure plate. The object of the present invention is to create a friction clutch of the type defined above, in which, with as little expense as possible, the oscillations occurring at least temporarily during the clutching and disengaging processes, can be prevented by simple and inexpensive means, without adversely affecting the function of

the friction clutch.

  In accordance with the invention, this is achieved by the fact that retaining stirrups are used to produce friction damping which reduces at least the axial oscillations of the pressure plate. The friction connection which is ensured by the retaining stirrups is then established at least when centrifugal forces act on the retaining stirrups which are pressed against a part which is axially movable by

compared to the pressure plate.

  The arrangement according to the invention ensures, in a particularly simple manner, that the means already provided in friction clutches and in the form of retaining stirrups can be used for damping oscillations of the

pressure plate.

  In a particularly advantageous manner, the friction connection can be provided between the retaining stirrups and the casing. The retaining stirrups can then bear directly against the casing or else a corresponding intermediate layer can be provided, formed for example of a friction material or a sliding material. The areas of the housing serving to support the retaining calipers can be advantageously arranged so as to be oriented at least approximately parallel to the axis of rotation of the friction clutch. These support zones can be

  created by parts of the housing wall.

  It may be advisable for the retaining stirrups to be fixed to the pressure plate and to hang axially behind the outer border area of the annular spring on the side opposite the pressure plate. Advantageously, the retaining stirrups are formed from spring steel and then the stirrups can be installed with pretension in the friction clutch and in particular advantageously so that the pressure plate is pushed dynamically against

the annular spring.

  A particularly advantageous arrangement can be obtained for the retaining calipers when they have a shape which guarantees elastic radial retention in the state of mounting in the friction clutch. The retaining calipers can then be installed with radial preload in the friction clutch and bear against the housing. It may be advisable for the friction action exerted between the retaining stirrups and the casing to occur at the axial height of the outer edge of the annular spring. This friction action can however also occur in another place and for this purpose the retaining stirrups must be arranged in correspondence. Thus, such retaining stirrups can also comprise fins formed unitarily and which bear elastically against a component which can be displaced relative to the pressure plate, such as the clutch housing. These fins can then be supported in a radial direction, or else in the case where they are bent in correspondence with respect to the basic body of the retaining stirrup, also laterally or else in a circumferential direction of the friction clutch. , against the corresponding component, and in particular to produce a

friction damping.

  The invention further converges a friction clutch which is arranged, in association with a flywheel with two flywheels, between a drive motor and a transmission, the flywheel located on the engine side being connected by means bolts with the engine crankshaft and at least the second mass of inertia, carrying the friction clutch using a clutch disc, has recesses allowing the passage of a bolt actuation tool ; in this regard, for disassembly of the flywheel with two inertia masses, the friction clutch and the clutch disc are separated from the second inertia mass and then the recesses of the second inertia mass are brought axially coinciding with the bolt heads by rotating the second mass of inertia in correspondence and then the bolts are loosened

  using a tool engaged through the recesses.

  The bolt head actuation tool can then be arranged in such a way that it is always ensured that, during unscrewing, the bolt heads can correctly penetrate into the recesses provided in the

second mass of inertia.

  Other characteristics and advantages of the invention will be highlighted in the rest of the

  description, given by way of nonlimiting example, in

  reference to the accompanying drawings in which: FIG. 1 represents a friction clutch provided with a retaining caliper arranged in accordance with the invention and which is mounted on a flywheel with two inertia masses, FIG. 2 represents a retaining caliper in an elevation view taken along arrow II of Figure 1, Figure 3.is a side elevation view of Figure 2, Figure 4 is a plan view of Figure 3, Figure 5 shows a detail of Figure 1, and Figure 6 shows the arrangement of a pivoting support for holding an annular clutch spring on a cover, Figure 7 is a partial sectional view of another arrangement, according to the invention , a friction clutch, Figure 8 is a sectional view on an enlarged scale of the retainer, which is shown in section in Figure 7, Figure 8 showing the relaxed position of this retainer, the Figure 9 is a plan view of the re element held, made according to arrow IX of Figure 7, and Figure 10 is an elevational view in

  correspondence to arrow X in FIG. 9.

  In FIG. 1 is shown a friction clutch 1 which is mounted on a so-called flywheel with two inertia masses 2. The flywheel with two inertia masses 2 consists of a primary inertia mass 3 , which can be coupled to the crankshaft of an engine, and a secondary mass of inertia 5, which can rotate in a limited manner relative to the primary mass of inertia by means of a bearing 4 and on which is

fixed friction clutch 1.

  With regard to the arrangement and the mode of operation of the flywheel with two inertia masses 2, reference is made to German patent application DE-OS 44 14 584, the content of which is disclosed is thus incorporated into the

this patent application.

  The friction clutch 1 has a cover 6 on. which is pivotally held by an annular spring acting as a lever with two arms. The annular spring 7 comprises tongues 7a, oriented radially inwards, for actuating the friction clutch as well as an outer base body 7b, of annular shape, connected unitarily to the tongues 7a and which serves as an accumulator for energy. The annular spring 7 is mounted so as to be able to pivot between a pivoting support 8 situated on the cover side and a pivoting support 9 provided on the side of the annular spring which is opposite to the cover. The pivoting supports 8, 9 are constituted, in the embodiment shown, by metal wire rings which are connected axially to the cover 6 by means of rivets 10 which extend radially in the base body 7b, axially through the annular spring. Inside the cover 6, a pressure plate 11 is provided, which is connected to the cover 6 by means of elements 12 in the form of elastic blades, without the possibility of relative rotation but

  however with the possibility of limited axial offset.

  In the embodiment shown, the elements 12 in the form of elastic blades are connected to the rivets 10 and simultaneously serve to axially support the pivot supports 8, 9 as well as the annular spring 7. By their other end, the elements 12 in in the form of elastic blades, are connected in a non-rotating manner to the pressure plate 11, and in particular in a manner analogous to that which has been shown in FIG. 1 of the aforementioned German patent application DE-OS 44 14 584. The cover clutch 6, also called "casing", firmly connected to the secondary inertia mass 5, is also securely connected to a component 13 in the form of a hollow cylinder, in particular advantageously by bolting, as has been described in the application of the aforementioned German patent DE-OS 44 14 584. The component 13 in the form of a hollow cylinder surrounds the secondary mass of inertia 5 and is firmly connected thereto. The friction linings of a clutch disc 14 are axially clamped between the pressure plate 11 and the secondary inertia mass 5, forming a back pressure plate. The friction clutch 1 further comprises retaining stirrups 15, which are firmly connected to the pressure plate 11 and which hook, by means of a hook-shaped zone 16, behind the outer edge of the annular spring. 7 on the side of this

  last one opposite the pressure plate 11.

  Advantageously, three such retaining stirrups 15 are provided which are distributed at equal intervals over the

around the pressure plate 11.

  The retaining stirrups 15 are arranged so that, in the assembled state, they exert a clamping force on the annular spring 7, so that the pressure plate 11 is applied against the underside of the annular spring 7. The outer edge of the annular spring 7 is thus tightened elastically between the bearing zones 16a of the hook-shaped parts 16a of the retaining stirrups 15 and the bosses 17 of the pressure plate 11. As shown in FIG. 1, the zones of contact of the bearing parts 16a and the bosses 17 are advantageously aligned axially, with the annular spring 7 disposed between them. However, these contact zones can also be offset in a radial direction and in this respect, however, due to the axial prestressing of the elastic stirrups 15, the annular spring 7 is subjected to a torque which has an influence on the force exerted by this spring. annular 7 on the support bosses 17 of the

pressure plate 11.

  In the embodiment shown, the retaining stirrups 15 are fixed to the radially outer peripheral surface of the pressure plate 11, and in particular in the embodiment shown using screw connections 18. However, the stirrups retainer 15 could also be similarly connected to a pressure plate, as is

  known for example from the US patent US-

  3,640,364, that is to say by means of a radially oriented zone which is fixed by riveting to the corresponding pressure plate. Riveting can then be used simultaneously to fix the elements in the form of elastic blades establishing the rotary connection between the pressure plate and the casing. In addition, the retaining stirrups according to the invention can also be individually linked to the elements in the form of an elastic blade which establish the non-rotating connection between the corresponding pressure plate and

the housing.

  As shown in FIG. 2, the retaining stirrups 15 comprise, in a foot area 20, a recess 19 in the form of a hole for a fastening means 18. The hook-shaped area 16, arranged after the area fixing 20, is arranged so that it bears, at least under the effect of a centrifugal force, against an area 21 of the wall of the cover or casing 6. Advantageously, however, the retaining brackets 15 are arranged so that they are mounted with a certain radial preload in the friction clutch 1, the parts 16b of the hook-shaped zone 16 then pressing elastically against the wall zone 21 oriented axially. It is thus ensured that there is always a friction connection between the pressure plate 11 or the retaining stirrups and the casing 6. In the embodiment shown, the support between the calipers 15 and the casing 6 is established at the axial height of the outer edge zone of the annular spring 7. This support can however also be established in another place and in this respect the retaining stirrups 16 must be profiled in correspondence. Thus, for example, a retaining stirrup 15 can, as shown in FIG. 2, also include arms 22 formed in one piece and able to bear against the casing 6 with a prestress. In the embodiment shown, the wall zones 21, against which the retaining stirrups 15 bear radially, are oriented exactly axially. These wall zones 21 can however - by considering them in the axial direction of the clutch - also be oriented by a determined angle so that, during an axial offset of the pressure plate 11, for example during a process of disengaging the friction clutch 1, the radial preload of the retaining stirrups is modified, by undergoing for example, in the case of a disengagement an increase or else however a

  decrease if more appropriate.

  The extent of the wall zones 21 against which the retaining stirrups 15 are supported is dimensioned such that this support, or else the friction connection, advantageously manifests itself throughout the duration of the friction clutch 1. This consequently means that, also in the case where the friction linings of the clutch disc 14 are worn, there is a bond by conjugation of forces or a bond by friction conjugation between the calipers

retainer 16 and housing 6.

  The support of the zones 16b of the retaining stirrups 15 against the casing 6 can be carried out either directly, as shown in FIG. 1, or indirectly. Thus, for example, a friction or sliding material can be placed between the bearing zones 21 and the retaining stirrups 15, that is to say an intermediate layer which can be carried by the casing 6 and / or by the different

retaining brackets 15.

  It may also be advisable for the retaining stirrups 15 to be provided with a coating at least in the region of the contact parts 16b. This coating can be formed for example by a layer of phosphate or by a layer of hard nickel. Where appropriate, the casing 6 may also include a coating corresponding at least to the areas cooperating with the

retaining brackets 15.

  The retaining stirrups 15 arranged as elastic stirrups, ensure that, when the friction clutch 1 is actuated, the pressure plate undergoes axially a forced offset under the effect of the annular spring 7. Under the effect of the friction connection existing between the retaining stirrups 15 and the casing 6, it is ensured that the axial oscillations of the pressure plate occurring during the clutching and disengaging processes are damped, so that one is ensuring a correct separation between the friction linings of the clutch disc 14 and the friction surfaces of the pressure plate 11 and the back pressure plate 5. In addition, the retaining brackets 15 make it possible to eliminate noise which could be produced for example by abutment of the bosses 17 against the annular spring 7 during

  pressure plate 11.

  The arrangement of the retaining calipers 15 according to the invention thus makes it possible to obtain a simple and inexpensive solution for damping the axial oscillations of the pressure plate 11, and in particular over the entire service life of the friction clutch. 1. Thus, thanks to the simple and elegant arrangement of the friction clutch according to the invention, what is called switching rattling is avoided under the effect of axial oscillations of the pressure plate. In addition, the damping by friction with a view to eliminating axial oscillations of the pressure plate 11 can be modified, for example increased, during an increase in the speed of rotation by means of a corresponding arrangement of the retaining calipers in what

concerns their elasticity.

  The group shown in Figure 1 - consisting of the friction clutch 1, the disc

  clutch 14 and flywheel with two flywheels 2 -

  can, as described in the German patent application already cited DE-OS 44 14 584, be transported or shipped in this condition and be fully attached to the crankshaft of an engine in the assembly line of the plant of automobile manufacturing. The dismantling of the complete group by means of a corresponding bolting tool can be carried out in a manner analogous to mounting and in this respect however it is initially necessary to bring the openings, provided for a passage of the bolting or dismantling tool in the annular spring 7 of the clutch disc 14 and of the second mass of inertia, in positions at least substantially in alignment

axial to reach the bolts.

  It may however also be advantageous that, for a disassembly of the flywheel with two mass of inertia 2 of the crankshaft of an engine, initially the clutch 1 is separated or disassembled from the secondary mass of inertia 5, so that also the clutch disc 14 can be removed. Provided that the springs of the damper 24, arranged between the two masses of inertia 3 and 5 and can be compressed into one. circumferential direction, do not push the two masses of inertia 3 and 5 in a defined initial position o the recesses 5a provided in the secondary mass of inertia 5 do not come to be placed axially practically in alignment with the heads of bolts 23, it is necessary if necessary to rotate the

  secondary inertia mass 5 of a corresponding angle.

  As soon as the sets of holes 5a of the secondary inertia mass 5 and the bolt heads 23 are arranged at least approximately in mutually aligned positions, it is possible to loosen the bolts using a corresponding tool 25 , which is shown in Figure 5 and which is engaged in the holes 5a. It is advisable in this regard that the bolting tool has a contour which is adapted at least approximately to the diameters or contours of the recesses 5a so that it can be ensured that, when the bolts 23a are unscrewed, their heads 23 can engage in the recesses Sa of the secondary inertia mass 5. It is particularly advantageous that the bolting tool 25 has in the region of the recesses 5a, a section which is tangent to a circle having a diameter approximately at the less equal to or greater than the circle tangent to the outer contour of a bolt head 23. To avoid jamming between the bolt heads 23 and the secondary inertia mass 5, the bolt heads 23 and / or the recesses 5a may include chamfers which constitute surfaces

introductory assistance.

  The mounting system shown in FIG. 6 for a pivoting mounting of an annular spring 107 on a casing or cover 106 can also be used in

  a friction clutch 1 such as that of FIG. 1.

  The pivoting support located on the cover side consists of imprints 108 in the form of bristles which are created in the cover 106 in the circumferential direction between the retaining means 110. The retaining means 110 form a single piece with the cover 106. The retaining means 110 arranged in the form of lugs are formed from the material of the cover 106 in a similar manner to that which has been described in the German patent application DE-OS 44 20 251 and in the application patent filed in the United States under serial number 08 / 264.557. According to the invention, however, it is not necessary to involve any additional support means, such as for example the metal wire ring 9 of FIG. 1, because the end zones 110a of the holding means 110 are directly profiled to support the annular spring 107. To guarantee correct support and pivoting of the annular spring 107 on the retaining means 110, the annular spring 107 comprises, in the region of the recesses 107a, through which the retaining means extend axially 110, indents 197b of curved or rounded shape around which the holding means or the legs 110 or else their bearing area 110a, are arranged or curved. The parts 110b of the tabs 110 which hook below the annular spring 107 or its base body 107c of annular shape, are arranged so that the annular spring 107 can pivot correctly relative to the cover, and this also when the clutch disc (14 in Figure 1) is worn. To this end, in the example of embodiment shown and in the case of a new friction clutch and also of a new clutch disc, there is between the zones 110b and the base body 107c an angle 112. This angle 112 allows the modification of taper of the annular spring 107, necessary during the service life of the friction clutch and which allows a. compensation for wear on the linings of

clutch disc friction.

  In the case of an arrangement of a pivoting support in accordance with FIG. 6, it is advisable for the tabs 110 to be connected to the cover 106 so that the zones 110a catching below the annular spring 107 are stressed or pushed by a determined force towards the pivoting support 108 located on the cover side. In this regard, reference is made to the patent applications already cited and to United States patent 4,781,820. In accordance with this prior art, the holding means 110 are connected to the base body proper of the cover by means of parts of this cover acting as elastic zones in torsion or elastic zones in bending, which makes it possible to compensate for a wear in the area of the ring spring pivot bearings. An arrangement of a pivoting support for an annular spring 107 in accordance with FIG. 6 has the advantage that, by means of a simple bending or of a simple folding of the end zones 110a of the tabs 110, the annular spring 107 can be pivotally mounted on the cover 106. During the folding process of the holding elements 110, the base body 107c of the annular spring 107 serves as a support part in

  thus practically constituting a folding tool.

  The friction clutch 201 partially shown in FIG. 7 is produced, independently of the particular arrangement of the retaining means 215, in a manner analogous to the friction clutch 1 of FIG. 1 and it can be mounted, also analogously to this clutch, so there is no need to

  redo a detailed description.

  The retaining means 215, which axially connect the annular spring 207 to the pressure plate 211, comprise a base body 207 of annular shape which, in the embodiment shown, acts like a membrane or a flexible spring, as well as arms 217, starting from the outer edge of the base body 216 and forming retaining elements which ensure the connection of the pressure plate 211 axially with the annular spring 207. As shown in FIG. 9, provision is made in this embodiment four retaining elements 217 distributed at equal intervals around the periphery. Figure 8 shows that, in the relaxed state, that is to say not mounted, of the retaining means 215, the base body 216 of annular shape is arranged in the manner of an annular spring. In addition, it can be seen that the arms or retaining elements 217 are separated by offset or pivoting radially in the direction of the axis of rotation of the clutch 201 relative to the position they occupy in the clutch 201 in accordance with the Figure 7. Figures 7 and 8 also show that during the assembly of the annular spring 207, the housing 206 and the pressure plate 211, the base body 216 of annular shape, acting as an elastic ring, changes taper , and in particular in the direction of a decrease in taper whereas, on the other hand, the arms 217 are spaced radially from the axis of rotation of the clutch 201 by pivoting and bear radially

  outside against pressure plate 211.

  The retaining means 215 arranged as an elastic ring or a retaining ring are produced in such a way that, in the assembled state, they exert a clamping force on the annular spring 207, which causes the pressure plate 211 is applied against the lower side of the annular spring 207. The elastic ring 216 forms a support zone 218 of annular profile, which is located on the side of the spring

  annular 207 which is opposite to the pressure plate 211.

  The support zone 218 may extend over a complete circle but it is however also possible that it is composed of several zones in the form of sectors, in which case at least in part of the circumferential extent of the legs 217, it there must be support zones through which the retaining ring 215 bears against the annular spring 207. The contact zones of the support parts 218 and the bosses 219 of the pressure plate with the annular spring 207 are advantageously arranged, at least approximately, in respective axial alignment and in this regard, as shown in Figure 7, there may also be a radial offset. FIG. 7 also shows that the contact zones between the retaining ring and the annular spring 207 are slightly offset radially inwards with respect to the contact zones between the

  bosses 219 and the annular spring 7.

  When mounting the friction clutch 201, and before the annular spring 207 is pivotally fixed in a 3D manner on the clutch housing 206, the elastic ring 215 is put in place in the housing 206. This housing 206 comprises a bearing area 206a of annular shape, against which the tongues 220 formed axially can bear radially inwardly on the base body 216 of annular shape. In the mounting condition in new condition of the friction clutch 201, the pressure plate 211 occupies the axial position shown in FIG. 7 so that the base body 207a of annular shape of the annular spring 207 is practically tightened in a flat layout. As shown in a comparison of FIGS. 7 and 8, one obtains, at least in the state of assembly in the new state of the friction clutch 201, an axial tightening of the base body 216 of annular shape between the annular spring 207 and the bearing areas 206a of the casing 206. The force exerted axially by the base body 216 of annular shape is added to the force exerted by the

annular spring 207.

  As shown in FIGS. 7 to 10, the retaining elements 217, which are preloaded in the radial direction, bear radially against external zones 221 of the pressure plate 211. The arms 217, extending in the axially essential, comprise in the illustrated embodiment, two outer branches 222, 223, which are connected with each other, at their ends opposite to the base body 216 of annular shape, by means of a transversal link 224. From this transverse link 224 again leaves a tongue 225, which is oriented axially in the direction of the base body 216 of annular shape. The free end 226 bears with radial preload against parts 225 of the casing 206. The parts 227 are located, in the embodiment shown in FIG. 7, in the region of an axially oriented wall 228, of the casing 206. As a comparison of FIGS. 7 and 8 shows, the tongues 225 protrude radially from the branches 222, 223 in the unassembled state of the elastic ring 215 whereas, on the other hand, in the assembled state of this ring elastic, the tongues 225 associated respectively with the two branches 222, 223 are located, at least approximately, in the same plane as the said branches 222, 223. The tongue end 226 is provided with a curved profile and it is placed in connection friction with the housing 206. This ensures that there is always a friction connection between the pressure plate 211 or the annular spring 207 and the housing 206. The axial connection between the retaining element or the elastic ring eu 215 and the pressure plate 211 is established via a link 229. by conjugation of forms. To this end, the branches 217 comprise, at their free end directed towards the pressure plate 211, tongues 230 which hook axially below radially outer zones of the pressure plate 211. As shown in FIGS. 8 and 10, the tongues 230 extend in an axial direction before the mounting of the elastic ring 215 in the clutch 201. As soon as the pressure plate 211 has been put in place in the casing 206 and there has been a corresponding tightening of the annular spring 207, for example at least of the axial offset of the pressure plate 211, the tongues 230 are bent radially inwards so as to axially tighten the pressure plate 211 with the spring

  annular 207 by means of the elastic ring 215.

  The structural arrangement can however be made in such a way that corresponding zones 230, directed radially inwards, are already provided before mounting of the elastic ring 216. The arm 217 or the branches 222, 223 must then have a corresponding radial elastic deformation capacity, which allows zones 230, directed radially inwardly, to be guided axially above corresponding zones of the pressure plate 211 and, after a determined position has been reached,

  again retract radially inward.

  Between the retaining element 215 and the casing 206,

  an anti-security system is also provided

  rotation. This anti-rotation security system 231 is created by means of arms 232 which are carried by the retaining element 215 and which engage in corresponding recesses in the casing 206. As shown in FIGS. 8 and 9, these arms 232 are formed, in the embodiment shown, on the inner radial edge of the base body 215 of annular shape, and in particular, considering a circumferential direction, in the area

tabs 225.

  The friction hysteresis occurring under the effect of the friction exerted between the tongues 226 and the casing 206 produces at least the same effects as the friction action exerted, as this has been described in the figure. 1, between the retaining brackets 15

and the housing 6.

  - .. As shown in particular in FIG. 8, the retaining element 215 comprises, radially outside the support zones 218, zones 233 in the form of hooks or arcs, which are arranged so that the parts 207b of the annular spring which are located radially outside the bearing zones 218 can be moved by pivoting, for the purpose of disengaging the friction clutch 201, without coming to bear against the abovementioned zones 233 . The base body 216 of annular shape of the retaining element 215 occupies, in the state of assembly in the friction clutch, also a corresponding arrangement which allows a pivoting movement of the annular spring 207. The zones 233 in shape arcs are located between the base body 216 of annular shape and

branches 222, 223.

  In a variant of FIGS. 7 to 10, it would also be possible to use several retaining elements distributed around the periphery. In the embodiment considered, four such retaining elements could be used, distributed for example with a respective offset of 90 around the periphery. We can highlight such an arrangement using FIG. 9 when we delete in this figure the areas of the base body 216 of annular shape which extend in a circumferential direction between the branches 222, 223 or the arms 217. The tongues 232 and the cover 206 are then advantageously adapted to each other so that the corresponding retaining elements

  are blocked or supported radially outwards.

  This radial locking could also be established by a combination of shapes between the retaining elements and the annular spring 207. For this purpose, for example zones in the form of tongues, similar to the tongues 232, could engage in corresponding recesses of the annular spring 207 or could be applied against corresponding support contours of this spring

ring finger 207.

  The friction occurring between zones 226 and 227 is a function of the force acting on the tongues 225 under the effect of the centrifugal force occurring during the rotation of the clutch 201. This therefore means that the damping by friction

  increases as the speed of rotation increases.

  Because the base body 216 of annular profile is arranged in the manner of an annular spring,

  this can have a force- characteristic curve

  race that is not linear. By means of a corresponding choice of this characteristic spring curve or else of a corresponding installation position of the base body 216 of annular shape in the new state of the clutch, it is thus possible to act on the clamping force exerted on the pressure plate 211 during the service life of the friction clutch. Also the evolution of the declutching force of the friction clutch 201 is influenced by the basic body 216 in

annular spring form.

  The claims filed with the request for

  patent are drafting proposals without detrimental effect for obtaining future patent protection. The Applicant also reserves the right to claim other highlighted characteristics

  so far only in the description and / or

sure. the drawings.

  Attachments used in

  secondary claims relate to other wagers

  implementation of the subject-matter of the main claim by the characteristics of the corresponding secondary claim, but they should not be considered as a renunciation of obtaining specific independent protection of the characteristics of the

  related secondary claims.

  The objects of these secondary claims

  also constitute particular inventions which are of an independent conception of the objects of

  previous secondary claims.

  The invention is also not limited to

  examples of embodiments given in the description. At

  on the contrary, within the framework of the invention, it is possible to envisage numerous variations and modifications, in particular variants, elements and combinations and / or materials which are inventive, for example by combination or modification of certain particularities, or elements, or operational steps, which have been described in relation

  with those described in the general description, the

  embodiments and claims and which are

  contained in the drawings leading, by a combination of features to a new object, or to new operating steps, or to new sequences of operating steps, provided that this also relates to manufacturing, control and

Implementation.

22 2768787

Claims (14)

  1. Friction clutch comprising a casing, an annular spring pivotally mounted thereon and urging a pressure plate connected in a non-rotating manner to the casing, the annular spring (107) comprising an outer base body of annular shape, from which protruding tongues oriented radially inwards and separated from each other by slots opening into adjacent recesses provided in the base body, and furthermore legs (110) formed unitarily with the material of the casing extend axially through recesses (107a) of the annular spring and are bent, on the side of the annular spring (107) which is opposite the casing, so as to maintain this spring with the possibility of pivoting, clutch characterized in that the tabs (110 ) are bent directly around the areas of the base body of the annular spring which are adjacent   to the corresponding recesses (107a).   2. Friction clutch according to claim 1, characterized in that the annular spring (107) serves as a support tool for bending the end zones (llOa) legs (110).   3. Friction clutch according to one of   claims 1 or 2, characterized in that the spring   annular mounted so as to be able to pivot thereon and urging a pressure plate, is connected to the casing in a non-rotating manner but nevertheless with the possibility of limited axial offset, and o it is provided for forced retention of the pressure plate during 'a pivoting movement of the annular spring, retaining stirrups between the annular spring and the pressure plate, the retaining stirrups (15) comprising, at least under the action of a centrifugal force, a connection by friction conjugation (in 16b, 21) with a component movable axially relative to the pressure plate. 23 2768787   4. Friction clutch according to one of   Claims 1 to 3, characterized in that the connection   by friction conjugation is established between stirrups retainer (15) and the housing (6).   5. Friction clutch according to one of   Claims 1 to 4, characterized in that stirrups   retainers (15) bear directly on the housing (6).   6. Friction clutch according to claim 5, characterized in that the bearing zones (21) of the housing for the retaining stirrups (15) are created by zones of the housing wall which are oriented substantially axially. 7. Friction clutch according to one of   Claims 1 to 6, characterized in that stirrups   retainers (15) are fixed on the pressure plate (11) and hook axially behind the outer edge area of the annular spring on the side opposite the pressure plate.   8. Friction clutch according to one of   Claims 1 to 7, characterized in that stirrups   retainers (15) are made of spring steel and are pre-tensioned so that the pressure plate (11) is dynamically pushed against the annular spring (7).   9. Friction clutch according to one of   Claims 1 to 8, characterized in that stirrups   retainers (15) are shaped so that they are elastically prestressed in a radial direction in the state of mounting in the clutch friction.   10. Friction clutch according to one of   claims 1 to 9, characterized in that stirrups   retainers (15) are mounted with radial preload in the friction clutch and bear against the housing.   11. Friction clutch according to one of   Claims 1 to 10, characterized in that the action of   friction between retaining stirrups (15) and the housing 24 2768787   (6) occurs at the axial height of the outer edge of the annular spring (7).   12. Friction clutch comprising a casing, an annular spring pivotally mounted thereon and urging a pressure plate which is connected to the casing in a non-rotating manner, but nevertheless with the possibility of limited axial offset, characterized in that the annular spring and the pressure plate are coupled for their movements by means of connection means (15) and the connection means (15) comprise a connection by friction conjugation (at 16b, 21) with a component movable axially by report pressure plate.   13. Friction clutch according to claim 10, characterized in that the connecting means are arranged and / or act in accordance with at least one of claims 4 to 11.   14. Friction clutch according to one of   claims 1 to 13, characterized in that it is   arranged in connection with a flywheel with two inertia masses between a drive motor and a transmission, the inertia mass situated on the engine side being connected by means of bolts with the crankshaft of the engine and at least the second mass d inertia, carrying the friction clutch in association with a clutch disc (14), comprising recesses (5a) to allow the passage of a bolt actuation tool, for disassembly of the flywheel two inertia masses, initially the friction clutch (1) and the clutch disc being removed from the second inertia mass, then the recesses provided in the second inertia mass being brought axially in alignment with the heads of bolts by means of a corresponding rotation of the second mass of inertia and then the bolts being loosened using a tool (25) engaged through the recesses.