GB2342704A - A clutch with twin mass flywheel fixed to an engine by screws for dismantling purposes - Google Patents

Abstract

A clutch 1 has a first flywheel mass 3 fixed to an engine crankshaft by screws 23a which are accessible through recesses 5a in second flywheel mass 5. A tool (25, fig 5) passes through recesses 5a when the second flywheel mass 5 is rotated so as to bring the recesses 5a and screws 23a into axial alignment. Before the second flywheel mass 5 is rotated the clutch 1 and clutch disc 14 are dismantled form the second flywheel mass 5. The tool (25) projects through the recesses 5a and is contoured so as to match the recesses 5a diameter. In another embodiment tabs (110, fig 6) integral with a clutch housing are provided. These tabs are bent down around areas of a diaphragm spring 7, thereby providing a swivel connection for the diaphragm spring 7 on the cover 6.

Description

FRICTION CLUTCH The invention relates to a friction clutch, more particularly for motor vehicles, with a device which dampens the vibrations of the pressure plate which occur particularly during the engagement and disengagement process whereby unacceptable noises can also be suppressed. The invention relates more particularly to a friction clutch with a housing and a diaphragm spring which is swivel mounted on the housing and which biases a pressure plate which is connected to the housing rotationally secured but axially displaceable to a restricted amount.

According to a first aspect of the invention there is provided a friction clutch which is provided in connection with a twin-mass flywheel between a drive motor and a gearbox wherein the flywheel mass on the engine side is connected by screws to the output shaft of the motor and at least the second flywheel mass supporting the friction clutch together with a clutch disc has recesses for passing through an operating tool for the screws wherein in order to dismantle the twin-mass flywheel first the friction clutch and the clutch disc are dismantled from the second flywheel mass and then the recesses of the second flywheel mass are brought into axial alignment with the screw heads by turning the second flywheel mass accordingly whereupon the screws are released by a tool passing through the recesses.

According to a second aspect of the invention, there is provided a friction clutch with a housing and a diaphragm spring mounted for swivel movement thereon and biasing a pressure plate connected rotationally secured to the housing wherein the diaphragm spring has an outer ring-shaped body from which extend radially inwardly aligned tongues which are separated from each other by slits which open into recesses adjoining the body, furthermore tabs formed integral with the housing material extend axially through recesses of the diaphragm spring and on the side of the diaphragm spring remote from the housing are bent down for swivel holding same, wherein the tabs are bent down directly round the areas of the body of the diaphragm spring adjoining the corresponding recesses.

Lift bars may be provided between the diaphragm spring and pressure plate in order to lift up the pressure plate automatically during swivel movement of the diaphragm spring wherein the lift bars have at least under the action of centrifugal force a friction connection with a component part which is axially movable relative to the pressure plate. This arrangement makes use of the lift bars to damp vibrations of the pressure plate.

In a particularly advantageous way the friction contact can be between the lift bars and the housing. The lift bars can be supported directly on the housing, or it is also possible to provide an intermediate layer, eg of friction or sliding material. The areas of the housing which make contact with the lift bars can advantageously be aligned at least approximately parallel to the axis of rotation of the friction clutch. The contact areas can be formed by wall areas of the housing.

It can be expedient if the lift bars are fixed on the pressure plate and engage axially behind an outer edge area of the diaphragm spring on the side remote from the pressure plate. Preferably the lift bars consist of spring steel.

These bars can then be mounted with pretension in the friction clutch, so that the pressure plate is biased with force against the diaphragm spring.

It is particularly advantageous if the lift bars have a shape which ensures an elastic radial pretension in the installed state in the friction clutch. The lift bars can then be installed with radial pretension in the friction clutch and be supported against the housing. It can be advantageous if the frictional contact takes place between the lift bars and the housing axially level with the outer edge of the diaphragm spring. This frictional contact can however also be made at any other point with the lift bars being designed accordingly. The lift bars can have integral moulded wings which are supported elastically against a component part such as the clutch housing relative to which the pressure plate is movable. These wings can be supported radially or (if they are angled correspondingly relative to the body of the lift bars) also laterally, viewed in the circumferential direction of the friction clutch, on the corresponding component part, namely to produce friction damping.

The operating tool for the screw heads can be designed so that it is always ensured that during unscrewing the screw heads can project satisfactorily into the recesses provided on the second flywheel mass.

The diaphragm spring and the pressure plate can be coupled together by connecting means which are in frictional contact with a component part relative to which the pressure plate is axially movable.

The invention will now be explained in further detail with reference to Figures 1 to 4 in which: Figure 1 shows a friction clutch with a lift bar according to the invention mounted on a twin-mass flywheel; Figure 2 shows a lift bar viewed along the arrow II in Figure 1; Figure 3 shows a side view of Figure 2; Figure 4 is a plan view of Figure 3; Figure 5 is a detail of Figure 1; Figure 6 shows a design of the swivel bearing for holding a clutch diaphragm spring on a cover.

Figure 7 is a partial sectional view through a further design of a friction clutch according to the invention; Figure 8 is an enlarged section of the lift element which is shown in section in Figure 7 wherein Figure 8 shows the relaxed position of this lift element; Figure 9 is a plan view of the lift element according to arrow IX of Figure 7; and Figure 10 is a view according to the arrow X of Figure 9.

Figure 1 shows a friction clutch 1 which is mounted on a socalled twin-mass flywheel 2. The twin mass flywheel 2 consists of a primary mass 3 connectable with the output shaft of a motor and a second flywheel mass 5 which can be rotated a restricted amount relative to the first flywheel mass through a bearing 4. The friction clutch 1 is fixed on the second flywheel mass.

For the construction and method of functioning of the twinmass flywheel 2 reference is made to DE-OS 44 14 584 whose disclosure is thus considered integrated into the present application.

The friction clutch 1 has a clutch cover 6 on which a diaphragm spring acting as a double-armed lever is held for swivel movement. The diaphragm spring 7 has radially inwardly aligned tongues 7a for operating the friction clutch as well as an outer ring-shaped body 7b connected integral with the tongues 7a and serving as an energy accumulator. The diaphragm spring 7 is mounted for swivel movement between a swivel bearing pad 8 on the side of the cover and a swivel bearing pad 9 on the side of the diaphragm spring remote from the cover. The swivel bearing pads 8,9 are formed in the illustrated embodiment by wire rings which are connected axially to the cover 6 by rivets 10 which extend radially inside the body 7b axially through the diaphragm spring. Inside the cover 6 is a pressure plate 11 which is connected by leaf spring elements 12 to the cover 6 rotationally secured but axially displaceable to a restricted amount. In the illustrated embodiment the leaf spring elements 12 are connected to the rivets 10 and serve at the same time for the axial support of the swivel bearing pads 8,9 and diaphragm spring 7. With their other end the leaf spring elements 12 are connected rotationally secured to the pressure plate 11, namely in a similar way to that shown in Figure 1 of the DE-OS 44 14 584 already mentioned.

The clutch cover 6 fixedly connected to the secondary flywheel mass 5 is fixedly connected to a hollow cylindrical component part 13, namely preferably by screws, as disclosed in the DE-OS 44 14 584 already mentioned. The hollow cylindrical component part 13 engages round the secondary flywheel mass 5 and is fixedly connected to same. The friction linings of a clutch disc 14 are tensioned axially between the pressure plate 11 and the secondary flywheel mass 5 forming the counter pressure plate.

The friction clutch 1 has lift bars 15 which are fixedly connected to the pressure plate 11 and engage behind the outer edge of the diaphragm spring 7 on the side of the diaphragm spring 7 remote from the pressure plate 11 by a hook area 16. There are preferably three such lift bars 15 which are evenly spread out over the circumference of the pressure plate 11.

The lift bars 15 are designed so that these exert in the installed state a pretension force on the diaphragm spring 7 whereby the pressure plate 11 is drawn against the underneath of the diaphragm spring 7. The outer edge of the diaphragm spring 7 is thus resiliently tensioned between the support areas 16a of the hook areas 16 of the lift bars 15 and the cams 17 of the pressure plate 11. As can be seen from Figure 1 the contact areas of the support areas 16a and cams 17 with the diaphragm spring 7 are mounted preferably axially opposite one another. These contact areas can however also be off-set radially relative to each other whereby then as a result of the axial pretension of the spring bars 15 a torque is introduced into the diaphragm springs 7 which influences the force exerted by the diaphragm spring 7 on the support cams 17 of the pressure plate 11.

In the illustrated embodiment the lift bars 15 are fixed on the radially outer sleeve face of the pressure plate 11, namely in the illustrated embodiment by means of screw connections 18. The lift bars 15 could however also be connected in a similar way to a pressure plate as has been known from for example the US-PS 3 640 364, thus through a radially aligned area which is rivetted to the corresponding pressure plate. The rivetting can thereby serve at the same time to fix the leaf spring elements producing the rotary connection between the pressure plate and the housing.

Furthermore the lift bars can also be formed in one piece with the leaf spring elements which produce the rotationally secured connection between the corresponding pressure plate and housing.

As can be seen from Figure 2 the lift bars 15 have in the foot area 20 a hole-like recess 19 for a fastener 18. The hooked area 16 adjoining the fixing area 20 is designed so that it is supported on a wall area 21 of the cover 6 at least under the effect of centrifugal force. However the lift bars 15 are preferably designed so that they are housed with a certain radial pretension in the friction clutch 1 whereby the sections 16b of the hooked area 16 resiliently adjoin the axially aligned wall area 21. It is thereby ensured that a friction connection is always present between the pressure plate 11 or lift bars 15 and the housing 6. In the illustrated embodiment the support between the bars 15 and housing 6 is axially level with the outer edge area of the diaphragm spring 7. This support can however also be provided at another point whereby the lift bars 16 have to be shaped accordingly. Thus for example a lift bar 15 as shown in Figure 2 can also have integral moulded extension arms 22 which can be supported on the housing 6 with pretension. In the illustrated embodiment the wall ares-21 on which the lift bars 15 are radially supported are aligned exactly axially. These wall areas 21 can however-viewed in the axial direction of the clutch-also have a certain angle so that during axial displacement of the pressure plate 11, eg during the disengagement process of the friction clutch 1 the radial pretension of the bars 15 changes eg increases during disengagement or where appropriate decreases.

The extension of the wall areas 21 on which the lift bars 15 are supported is measured so that this support or friction connection is present preferably throughout the entire service life of the friction clutch 1. This means that even with worn out friction linings on the clutch disc 14 there is a force locking or friction connection between the lift bars 16 and the housing 6.

The support of the areas 16b of the lift bars 15 on the housing 6 can take place either directly as shown in Figure 1 or indirectly. Thus for example a friction or sliding material can be provided between the support areas 21 and the lift bars 15, thus an intermediate layer which can be supported either by the housing 6 and/or by the individual lift bars 15.

It can however also be advantageous if the lift bars 15 are coated at least in the area of the contact sections 16b.

This coating can be formed for example by a phosphate layer or a hard nickel layer. Where required the housing 6 can also have a corresponding coating on at least the areas interacting with the lift bars 15.

The lift bars 15 designed as spring bars cause the pressure plate 11 to be moved axially automatically through the diaphragm spring 7 when the friction clutch 1 is operated.

Through the friction connection between the lift bars 15 and housing 6 it is ensured that the axial vibrations of the pressure plate occurring during the engagement and disengagement process are damped whereby a satisfactory separation is ensured between the friction linings of the clutch disc 14 and the friction faces of the pressure plate 11 and counter pressure plate 5. Furthermore the lift bars 15 can suppress noises which can be produced for example when the cams 17 strike the diaphragm spring 7 during vibration of the pressure plate 11.

The design of the lift bars 15 thus allows a simple costeffective solution for damping the axial vibrations of the pressure plate 11, namely throughout the entire service life of the friction clutch 1. Thus through the design of the friction clutch it is possible to avoid in a simple elegant way so-called gearbox chatter following axial vibrations of the pressure plate. Furthermore the friction damping can be changed, eg increased in terms of its elasticity at increasing speed for suppressing the axial vibrations of the pressure plate 11 through corresponding design of the lift bars.

The assembly illustrated in Figure 1 and comprising the friction clutch 1, clutch disc 14 and twin-mass flywheel 2 can as described in the DE-OS 44 14 584 already mentioned be transported and despatched as such and can be fixed complete on the output shaft of an engine on the assembly line at a car manufacturing plant. The dismantling of the complete assembly by means of a corresponding screwing tool can be carried out in the same way as the assembly, whereby for this first the openings in the diaphragm spring 7 of the clutch disc 14 and second flywheel mass 5 provided for passing through the screwing or dismantling tool have to be brought into an at least substantially axially aligned position in order to reach the screws.

It can however also be advantageous if to dismantle the twin-mass flywheel 2 from the output shaft of an engine first the clutch 1 is removed or separated from the secondary flywheel mass 5 whereby the clutch disc 14 can also be removed. If the springs of the damper 24 which are mounted between the two flywheel masses 3 and 5 and can be compressed in the circumferential direction do not force the two flywheel masses 3 and 5 into a definite starting position where the recesses 5a provided in the secondary flywheel mass 5 come to lie axially practically in alignment with the screw heads 23 then where applicable the secondary flywheel mass 5 must be turned round a corresponding angle.

If the hole pattern 5a of the secondary flywheel mass 5 and the screw heads 23 are correctly positioned at least approximately over each other then the screws can be released by a corresponding tool 25 which as shown in Figure 5 projects through the bores 5a. It is thereby expedient if the screwing tool has a contour which at least approximately matches the diameter or contours of the recesses 5a whereby it can be ensured that when unscrewing the screws 23a their heads 23 can project into the recesses 5a of the secondary flywheel mass 5. It is particularly advantageous if the screwing tool 25 has in the area of the recesses 5a a crosssection which touches a circle with a diameter which is at least approximately the same size or larger than the circle touching the outer contours of a screwing head 23. In order to avoid canting between the screw heads 23 and the secondary flywheel mass 5 the screw heads 23 and/or the recesses 5a have corresponding inclined areas which form lead-in contours.

The bearing shown in Figure 6 for the swivel hold of a diaphragm spring 107 on a housing 106 can also be used with a friction clutch 1 according to Figure 1.

The swivel bearing pad on the cover side is formed by swagelike indentations 108 formed in the cover 106 in the circumferential direction between the retaining means 110.

The retaining means 110 are formed integral with the cover 106. The retaining means 110 formed as tabs are shaped out of the cover 106 in a similar way to that described in DE-OS 44 20 251 and US Patent Application Serial No 08/264,557. No additional supporting means such as for example a wire ring according to Figure 1 is then required since the end areas 110a of the retaining means 110 are used directly for supporting the diaphragm spring 107. In order to ensure a satisfactory support and swivelling of the diaphragm spring 107 on the retaining means 110 the diaphragm spring 107 has, in the area of the recesses 107a through which the retaining means 110 axially extend, curved or rounded indentations 107b around which the retaining means or tabs 110 or their support areas 110a are placed or bent. The sections 110b of the tabs 110 engaging underneath the diaphragm spring 107 or the ring shaped body 107b thereof are designed so that the diaphragm spring 107 can swivel satisfactorily relative to the cover and this is possible even when the clutch disc (14 in Figure 1) is worn. To this end in the illustrated embodiment and with new friction clutches and new clutch discs an angle 112 is provided between the areas 100b and the body 107b. The angle 112 allows the change in conicity of the diaphragm spring 107 which is required throughout the service life of the friction clutch to compensate the wear on the friction linings of the clutch disc.

In a design of the swivel bearing according to Figure 6 it is advantageous if the tabs 110 are connected to the cover 106 so that the areas 110 engaging underneath the diaphragm spring 107 are biased or stressed with a certain force in the direction of the swivel bearing pad 108 on the cover side. For this reference is made to the patent applications already mentioned and to the US PS 4 781 280. According to this prior art the retaining means 110 are connected by cover sections acting as elastic torsion areas or elastic bending areas to the actual body of the cover whereby wear in the area of the swivel bearing of the diaphragm spring can be compensated. A design of the swivel bearing for a diaphragm spring 107 according to Figure 6 has the advantage that by simple angling or bending of the end areas 110a of the tabs 110 the diaphragm spring 107 can be held for swivel movement on the cover 106. The body 107b of the diaphragm spring 107 serves as support during the bending of the retaining element 110 and thus forms in practice a bending tool.t The friction clutch 20 shown in part in Figure 7 is, apart from the special design of the lift means 215, designed similar to and can be used in the same way as the friction clutch 1 according to Figure 1 so that a detailed description of this is not necessary.

The lift means 215 which connect the diaphragm spring 207 axially to the pressure plate 211 comprise a ring-shaped body 216 which with the illustrated embodiment acts like a membrane or plate-spring, as well as extension arms 217 extending from the outer edge of the body 216 to form lift elements which connect the pressure plate 211 axially to the diaphragm spring 207. As can be seen from Figure 9 with this embodiment there are four lift elements 217 spread evenly over the circumference. It can be seen from Figure 8 that in the relaxed, thus non-assembled, state of the lift means 215 the ring-shaped body 216 is set up like a diaphragm spring. Furthermore it can be seen that the extension arms or lift elements 217 are off-set or swivelled radially in the direction of the axis of rotation of the clutch 201 opposite the position which they occupy in the clutch according to Figure 7. It is thus apparent from Figures 7 and 8 that when assembling the diaphragm spring 207, housing 206 and pressure plate 211 the ring-shaped body 216 acting as the spring ring changes its conicity, namely in the sense of reducing the conicity whilst the extension arms 217 are swivelled radially away from the axis of rotation of the clutch 201 and are supported radially outwards on the pressure plate 211.

The lift means 215 which are formed as a spring or lift ring are designed so that in the installed state they exert a tension force on the diaphragm spring 207 whereby the pressure plate 211 is drawn towards the underneath of the diaphragm spring 207. The spring ring 216 forms a ringshaped support area 218 which is mounted on the side of the diaphragm spring 207 remote from the pressure plate 211.

The support area 218 can extend over an entire circular circumference but it can however also consist of individual sector-shaped areas wherein at least in the circumferential extension area of the extension arms 217 supporting areas should be provided through which the lift ring 215 is supported on the diaphragm spring 207. The contact areas of the supporting areas 218 and of the pressure plate cams 219 with the diaphragm springs 207 are preferably mounted at least approximately axially opposite one another wherein as can be seen from Figure 7 a radial stagger can also be provided. It can be seen from Figure 7 that the contact areas between the lift ring 215 and the diaphragm spring 207 are off-set slightly radially inwards relative to the contact areas between the cams 219 and diaphragm spring 7.

When assembling the friction clutch 201 before the diaphragm spring 207 is fixed for swivel movement on the clutch housing 206, the spring ring 215 is placed in the housing 206. The housing 206 has a ring-shaped supporting area 206a on which the tongues 220 radially formed on the ring-shaped body 216 can be supported axially. In the assembled new state of the friction clutch 201 the pressure plate 211 occupies the axial position shown in Figure 7 whereby the ring-shaped body 207a of the diaphragm spring 207 is tensioned practically into a flat position. As can be seen by comparing Figures 7 and 8 at least in the assembled new state of the friction clutch 201 the ring-shaped body 216 is tensioned axially between the diaphragm spring 207 and the supporting areas 206a of the housing 206. The force applied axially by the ring-shaped body 216 is added to the force applied by the diaphragm spring 207.

As can be seen from Figures 7 to 10 the lift elements 217 which are pretensioned in the radial direction are supported radially on the outer areas 221 of the pressure plate 211.

The substantially axially extending extension arms 217 have in the illustrated embodiment two outer arms 222,223 which are connected together at their end remote from the ringshaped body 216 by a cross-section 224. From the cross connection 224 extends in turn a tongue 225 which extends axially in the direction of the ring-shaped body 216. The free end 226 is supported with radial pretension on sections 227 of the housing 206. The sections 227 are located in the illustrated embodiment according to Figure 7 in the area of an axially aligned wall 228 of the housing 206. As can be seen by comparing Figures 7 and 8 the tongues 225 in the non-installed state of the spring ring 215 protrude radially opposite the arms 222,223 whilst in the assembled state the tongue 225 associated each time with the two arms 222,223 lies at least approximately in one plane with these arms 222,223. The tongue end 226 is formed ball-shaped and is located in friction connection with the housing 206. It is thereby guaranteed that there is always a friction connection between the pressure plate 211 or the diaphragm spring 207 and the housing 206. The axial connection between the lift element or spring ring 215 and the pressure plate 211 is provided by a keyed connection 229. To this end the extension arms 217 have at their free end facing the pressure plate 211 tongues 230 which engage axially underneath radially outer areas of the pressure plate 211.

As can be seen from Figures 8 and 10 the tongues 230 extend axially prior to fitting the spring ring 215 into the clutch 201. Only after the pressure plate 211 has been placed in the housing 206 and a corresponding tensioning of the diaphragm spring 207 has taken place, eg by means of axial displacement of the pressure plate 211 are the tongues 230 bent round radially inwards in order to tension the pressure plate 211 axially by means of the spring ring 215 with the diaphragm spring 207. The structural design can however also be formed so that corresponding radially inwardly pointing areas 230 are present already prior to fitting the spring ring 216. The extension arms 217 or arms 222,223 must then have a corresponding radial elastic deforming capacity which allows the radially inwardly pointing areas 230 to move axially forward over the corresponding areas of the pressure plate 211 and spring back again radially inwards after reaching a certain position.

An anti rotation lock 231 is provided between the lift element 215 and the housing 206. The anti-rotation lock 231 is provided by means of the extension arms 232 which are supported by the lift element 215 and which engage in corresponding recesses of the housing 206. As can be seen from Figures 8 and 9 with the illustrated embodiment these extension arms 232 are formed on the radial inner edge of the ring shaped body 215, namely in the area of the tongues 225 viewed circumferentially.

The friction hysteresis occurring through the friction engagement between the tongues 226 and the housing 206 causes at least the same effect as the friction engagement which was described in connection with Figure 1 and is provided between the lift bars 15 and housing 6.

As can be seen in particular from Figure 8 the lift element 215 has radially outside of the supporting areas 218 hookshaped or curved areas 233 which are designed so that the diaphragm spring areas 207b provided radially outside of the supporting areas 218 can be swivelled in order to disengage the friction clutch 201 without coming to adjoin these areas 233. The ring shaped body 216 of the lift element 215 likewise has in the installed state in the friction clutch a corresponding position which allows the diaphragm spring 207 to swivel. The curved areas 233 are provided between the ring-shaped body 216 and the arms 222,223.

In a modification of Figures 7 to 10 individual lift elements spread out over the circumference could also be used. In the present embodiment for example four such lift elements could be used which can be mounted for example spread out over the circumference each off-set by 90 . A construction of this kind can be deduced using Figure 9 if in this drawing one imagines not to be there the areas of the ring-shaped body 216 which extend in the circumferential direction between the arms 222, 223 and the bearings 217.

The tongues 232 and the cover 206 are thereby preferably adapted to each other so that the corresponding lift elements are secured and supported radially outwards. This radial securing could however also be provided by a keyed connection between the lift elements and the diaphragm spring 207. To this end for example the tongue-like areas engage like the tongues 232 in corresponding recesses of the diaphragm spring 207 or adjoin corresponding support contours of the diaphragm spring 207.

The friction occurring between the areas 226 and 227 is dependent on the force which acts on the tongues 225 as a result of the centrifugal force which exists when the clutch 201 turns. This thus means that the friction damping increases with increasing speed.

Since the ring-shaped body 216 is formed like a diaphragm spring this can have a non-linear force-path characteristic line. By suitably selecting the spring characteristic line or by a corresponding installation position of the ringshaped body 216 in the new state of the clutch it is possible to influence the contact pressure force which acts on the pressure plate 211 during the service life of the friction clutch. Also the disengagement force curve of the clutch 201 is influenced by the plate-spring-like body 216.

The invention is also not restricted to the embodiment of the description. Rather numerous modifications and alterations are possible within the scope of the invention as defined by the claims, more particularly those variations, elements and combinations and/or materials described individually in connection with the description and embodiments and contained in the drawings or which through combinable features lead to a new subject or new method step or sequence of method steps whether they relate to manufacturing, testing or work processes.

Claims (14)

1. Claims 1. Friction clutch which is provided in connection with a twin-mass flywheel between a drive motor and a gearbox wherein the flywheel mass on the engine side is connected by screws to the output shaft of the motor and at least the second flywheel mass supporting the friction clutch together with a clutch disc has recesses for passing through an operating tool for the screws wherein in order to dismantle the twin-mass flywheel first the friction clutch and the clutch disc are dismantled from the second flywheel mass and then the recesses of the second flywheel mass are brought into axial alignment with the screw heads by turning the second flywheel mass accordingly whereupon the screws are released by a tool passing through the recesses.
2. 2. Friction clutch with a housing and a diaphragm spring mounted for swivel movement thereon and biasing a pressure plate connected rotationally secured to the housing wherein the diaphragm spring has an outer ring-shaped body from which extend radially inwardly aligned tongues which are separated from each other by slits which open into recesses adjoining the body, furthermore tabs formed integral with the housing material extend axially through recesses of the diaphragm spring and on the side of the diaphragm spring remote from the housing are bent down for swivel holding same, wherein the tabs are bent down directly round the areas of the body of the diaphragm spring adjoining the corresponding recesses.
3. 3. Friction clutch as claimed in Claim 2, wherein the diaphragm spring serves as a supporting tool for bending down the end areas of the tabs.
4. 4. Friction clutch as claimed in Claim 2 or Claim 3, wherein lift bars are provided between the diaphragm spring and pressure plate in order to lift up the pressure plate automatically during swivel movement of the diaphragm spring wherein the lift bars have at least under the action of centrifugal force a friction connection with a component part which is axially movable relative to the pressure plate.
5. 5. Friction clutch as claimed in Claim 4, wherein the friction connection is provided between the lift bars and the housing.
6. 6. Friction clutch as claimed in Claim 4 or 5, wherein the lift bars are supported directly on the housing.
7. 7. Friction clutch as claimed in Claim 6, wherein the supporting areas of the housing for the lift bars are formed by substantially axially aligned wall areas of the housing.
8. 8. Friction clutch according to any one of Claims 4 to 7, wherein the lift bars are fixed on the pressure plate and engage axially behind the outer edge area of the diaphragm spring on the side remote from the pressure plate.
9. 9. Friction clutch according to any one of Claims 4 to 8, wherein the lift bars are made of spring steel and are mounted pretensioned whereby the pressure plate is biased with force against the diaphragm spring.
10. 10. Friction clutch according to any one of Claims 4 to 9, wherein the lift bars are formed so that they are pretensioned radially resiliently when installed in the friction clutch.
11. 11. Friction clutch according to any one of Claims 4 to 10, wherein the lift bars are installed with radial pretension in the friction clutch and are supported on the housing.
12. 12. Friction clutch according to any one of Claims 4 to 11, wherein the friction engagement takes place between the lift bars and the housing axially level with the outer edge of the diaphragm spring.
13. 13. Friction clutch as claimed in any preceding claim, wherein the diaphragm spring and the pressure plate are coupled together in movement by connecting means and the connecting means have a friction connection with a component part which is axially movable opposite the pressure plate.
14. 14. Friction clutch as claimed in Claim 13, wherein the connecting means are formed and/or are active according to at least one of claims 2 to 9.