Abstract:
A torsional vibration damper for use in a motor vehicle power train has an input disc part connected to the vehicle engine and an output disc part to the downstream side of the power train. The disc parts are rotatable relative to each other against the action of an energy accumulator such as a coiled compression spring. The energy accumulator is seated in a suspension device that is divided into two socket parts. The socket parts are rotatable in relation to each other as well as in relation to the input and output disc parts. The input and output disc parts have biasing means engaging the socket parts so that, for a first sense of relative rotation between the input and output disc parts, the biasing means of the input disc part engage the first socket part and the biasing means of the output disc part engage the second socket part while, for a second, opposite sense of relative rotation, the biasing means of the input disc part engage the second socket part and the biasing means of the output disc part engage the first socket part, with the result that for either sense of relative rotation between the input and output disc parts, the energy accumulator is always force-biased in a compressive sense between the socket parts.

Description:
This is a continuation of International Application No. PCT/DE99/00898, filed Mar. 23, 1999 now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates to a torsional vibration damper for taking up and/or compensating for rotary shocks, especially torque fluctuations of an internal combustion engine, with at last two disc parts which are rotatable relative to each other against the action of at least one energy accumulator which is provided between the disc parts in the force transmitting path and acts at least in the circumferential direction. 
     Torsional vibration dampers of such kind are known and in accordance with one embodiment, can constitute divided flywheels with flywheel masses. Torsional vibration dampers of such kind normally comprise circumferentially spaced apart energy accumulators which are biased on the circumferential side through recesses or shaped areas in the two flywheel masses. By way of example, reference is made to FR PS 2 166 604. Such torsional vibration dampers are subject to pronounced wear upon the biasing devices and energy accumulators as a result of their design. Solutions have therefore been proposed such as, for example, in DE PS 35 15 928 using lubricant-filled energy accumulator chambers which are sealed on the outside but these are correspondingly expensive to construct and therefore involve increased manufacturing costs. 
     OBJECT OF THE INVENTION 
     Accordingly, it is an object of the invention to provide a torsional vibration damper of the kind described which is less susceptible to wear and thus exhibits a greater durability whilst at the same time optimizes production costs. Furthermore, a simple mounting of the energy accumulators in the flywheel masses is also to be made possible. The energy accumulators should be supported as uniformly as possible at their ends in the circumferential direction and secured against escape radially outwards in the event of high centrifugal forces. 
     SUMMARY OF THE INVENTION 
     This is achieved according to the invention by the provision of a torsional vibration damper which comprises between at least two relatively rotatable disc parts at least one energy accumulator in the force transmitting path, which is active at least in the circumferential direction, and which is housed in a suspension device divided into two socket parts, the two socket parts being adapted to be biased in dependence on the circumferential direction by biasing means of the two disc parts to compress at least one energy accumulator and the biasing devices each bias one socket part alternately in dependence on the direction of rotation. 
     Torsional vibration dampers of such kind can be equipped for example with simple disc parts and can be used as friction lining supports in a clutch, for example, in the power train between the drive unit and the gearbox. Furthermore, the disc parts can be provided with flywheel masses or can consist of flywheel mass elements whereby they can be used in the power train as a divided flywheel with two flywheel masses which can be rotated relative to each other against the action of the at least one energy accumulator. 
     The biasing means can advantageously be shaped as a bolt or stud fixed axially on the disc parts, and the disc parts can constitute circular discs and can be provided with flywheel masses and one disc part can be connected to the drive shaft of an internal combustion engine and the second disc part can be connected to the input shaft of a gearbox through a friction clutch or the like fixed on the second disc part. 
     The suspension or receiving device, which can also be used in conventional damping devices without flywheel masses, consists for suspension of the at least one energy accumulator, wherein four to eight, and preferably six, helical compression springs spread out over the circumference can be particularly advantageous, of two socket parts which for reasons of cost efficiency and easier mounting can be identical and face one another mirror symmetrically and can be fitted in each other turned by the angle of one energy accumulator socket whereby in the event of predetermined stressing they can transmit a basic friction torque in the torsion vibration damper at the points where they contact each other. Furthermore, stops or sockets for the energy accumulator corresponding to the relevant number of energy accumulators can be provided on each socket part and extend over the entire axial width of the suspension device and therefore engage in the relevant other socket part so that for each energy accumulator one stop or one biasing device can be formed at one circumferential end by the first socket part and thus by the first disc part and at the other end by the second socket part and thus by the second disc part. The large surface socket can advantageously be 70% and more of the area of the energy accumulator cross-sections and, therefore, the ends of the energy accumulators need not be ground as exactly flat as in conventional dampers or indeed grinding can be omitted completely. The inclination of a socket in the circumferential direction is preferably selected in such a way that it conforms to the inclination of the ends of the energy accumulators and thus the contact faces of the energy accumulator ends can be further optimized. 
     According to the invention, the two preferably identical socket parts are formed in such a way that they each have a ring-shaped carrier mounted at the outer circumference and a ring shaped support mounted on the inner circumference which both lie in one plane and have approximately half the axial width of the suspension device whereby on one axial side the sockets provided radially between the support rings protrude for the energy accumulators which when the two socket parts are assembled engage in each other. The outer support can have approximately the cross-sectional shape of a quarter circle or can be chamfered so that the suspension device overall can have approximately a semi circular profiled section or a profiled section on the outer circumference which is chamfered at the outer edges. 
     It can further be advantageous to limit the extent of angular movement of the two socket parts, that is the angular movement of the socket parts relative to the biasing means of the disc parts. To this end, in addition to the blocking of the energy accumulators—when using coil compression springs through the windings stopping against each other—stops can be provided on the sockets for the energy accumulators inside the outer support and these project circumferentially into the pockets in which the energy accumulators are housed whereby of each socket of the energy accumulator one stop projects into the pocket so that by selecting the length of the two stops projecting into the pockets it is possible to fix the turning angle in the circumferential direction. A turning angle is preferably selected which is smaller than that provided by the blocking of the energy accumulators. 
     The stops which are provided to limit the extent of angular movement advantageously serve at the same time as radial supports for the energy accumulators radially outwards, especially in the case of high centrifugal force action, and to this end can have the cross-section of a ring segment. A profiled section matching the cross-section of the energy accumulators can be formed as a support for the energy accumulators on the inside in the area of the pockets for holding the energy accumulators on the inner support whereby the overall profiled section is produced by fitting together the two supports of the socket parts. The inner circumference of the two inner supports can be designed flat so that the hanging device where required can be centered and/or mounted thereon. 
     When using coil compression springs as energy accumulators these can be wound according to the invention so that they have windings with different diameters. Coil compression springs can advantageously be used which starting and ending with a winding of larger diameter have alternately large and small windings. Furthermore it can be provided that the center point axis of the windings with large and small diameter is not the same—thus a concentric arrangement of the windings along the axial extension—but that the center point axis of the windings with smaller diameter is displaced parallel to the center point axis of the large windings so that on one side of the winding circumference the windings of small diameter can be inserted in the inner circumference of the windings of large diameter and on the other side can be mounted at the same radial height. An installation position of the coil springs can be advantageous with the insertable windings of small diameter on the outer circumference of the suspension device so that the radially larger compression path of the springs can be compensated for and the spring capacity can be optimized whereby the springs can be suspended in the corresponding sockets so that rotation is prevented. Springs of this kind can advantageously be used also in many other cases, for example, in disengagement devices as over dead center springs, compensation springs and/or return springs and the like. 
     Further sockets or openings can be provided at the sockets for the energy accumulators facing away from the socket faces for engagement of the biasing means of the flywheel masses. The biasing means of the disc parts advantageously consist of bolts engaging axially in a socket part for which half-shell shaped openings are impressed on the side of the energy accumulator sockets opposite the receiving faces for the energy accumulators and these openings form with the second socket part an approximately circular opening in which an axially aligned biasing means—here preferably bolts—of each disc part can enter without contacting one another. Therefore, during rotation of the two disc parts relative to each other, the two socket parts can be turned in the relevant direction of rotation of the disc parts and the energy accumulators can thereby be compressed about their neutral position by each disc part. This can lead to a more even biasing of the energy accumulators and thus to reduced wear, especially in the case of high speeds with corresponding centrifugal force action and with energy accumulators which are stretched in the circumferential direction accordingly. 
     In order to shield the suspension device from the action of the centrifugal force and/or to protect the suspension device from thermal stressing by the disc parts—particularly in the case of disc parts having flywheel masses of a divided flywheel which is connected to the output side on account of the ensuing friction heat through the clutch which can be attached here—the suspension device can be provided on its outer circumference with a corresponding reinforcement made for example of a heat-reflecting and/or tension-resistant material such as metal whereby this reinforcement can follow the surface profile of the outer support and can surround same over the entire circumference in cross-section approximately semi-circularly or chamfered over the outer edges or a reinforcement can be provided for each support, by way of example, by means of two circumferentially complete wire rings on the outer circumference of each support whereby a circumferential groove can be formed in the supports to guard against axial slipping of the rings. 
     Advantageously the suspension device is made from a plastic material whereby injection moulding processes are preferably used although a design of metal can also be advantageous. 
     The suspension device can be arranged for an ideal formation of the energy accumulators over the entire radius of the torsional vibration damper whereby advantages are gained when mounted in the area radially outside of the fastening screws of the first disc part on the drive shaft of the internal combustion engine, especially directly at the circumference of this screw circle. 
     The torsional vibration damper according to the invention can be fitted with a friction generating device acting in the range of the angular displacement between the two disc parts and which can include a base friction and/or a selected variable friction whereby the selected variable friction can be controlled by means of a friction control disc which can engage in a disc part or in a component part fixedly connected thereto and acts on a friction disc which is fixed securely on the other disc part or a component part connected to same whereby an intended turning play between the friction control disc and the disc part can cause a delayed friction. In this way a friction generating device can be designed so that the friction control disc engages by axially protruding teeth, preferably formed on its outer circumference, in recesses of one of the two disc parts, preferably in the force applying component—by way of example in the divided flywheel connected to the drive shaft—whereby the friction generating device can be mounted radially outside or radially inside the suspension device. The friction disc is advantageously inserted or snap-fitted by axially protruding studs rotationally secured on the other disc part preferably the one connected to the gearbox side or emitting the force. It can be further advantageous to make the friction force dependent on the force being applied to the energy accumulator, thus in dependence on the spring force in the case of coil compression springs. To this end, one side of the torsional vibration damper, for example, the side of the first flywheel mass can be fitted with conical biasing means which are placed against complementary conical sockets of the socket part and thus form a ramp. The friction disc is mounted axially between the flywheel mass and the energy accumulator sockets and can be placed in the neutral position of the energy accumulators friction-free or with a predetermined basic friction. If relative rotation takes place between the flywheel masses through biasing of the energy accumulators, then the socket part with the socket of the energy accumulators is moved along the ramp in dependence on the force being applied to the energy accumulators axially in the direction of the friction disc and thus the friction force is correspondingly increased. 
     A further inventive concept contemplates the provision of a torsional vibration damper whose biasing means are formed directly on, for example integral with, a disc part or a component part connected therewith. For example, it can be advantageous to design the biasing means of a disc part mounted on the gearbox side with a flywheel mass of axially aligned extension arms of the clutch cover fixed on the disc part or on the flywheel mass and/or to provide the biasing means on the drive side as radially aligned stops or a window recessed in the disc part according to the spatial extension of the energy accumulator. 
     Furthermore it can be advantageous to use a slip clutch which can have preferably a restricted turning angle. The slip clutch can be provided between a disc part on the gearbox side or drive side, preferably connected on the gearbox side, and the associated flywheel mass whereby the turning angle is restricted by recesses in the flywheel mass forming stops, in which corresponding extension arms of the disc part can be moved between two stops against the action of the friction force of the slip clutch. The friction devices establishing the friction force of the slip clutch can be mounted on the side of the disc part or flywheel mass facing the gearbox and/or internal combustion engine, for example, radially inside the friction face for the shift clutch and/or at the rear side of the flywheel mass formed as a contact pressure plate. 
     A further inventive concept involves the provision of an arrangement of several but at least two suspension devices radially spaced from each other so that two independent damping devices are formed which can be combined with each other and which can be formed in two stages or are designed for the purpose of increasing the torque which is to be damped and/or transmitted. Furthermore, it is conceivable that a suspension device be combined with a damping device fitted radially on the outside, for example in series connection, which has as energy accumulators in the form of curved springs and which can be filled with lubricant. Furthermore, it can be particularly advantageous for producing a particularly long-running torsional vibration damper to also grease or oil the hanging device or to operate same confined in a chamber in lubricating medium such as grease or oil or the like. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be explained in further detail with reference to the embodiments shown in FIGS. 1 to  11 . There are shown in: 
     FIG. 1 a cross-section through a torsional vibration damper according to the invention; 
     FIG. 2 an elevational view of a socket part of a suspension device according to the invention; 
     FIGS. 3 to  10  sections of further design samples of torsional vibration dampers according to the invention and 
     FIG. 11 a detail of a suspension device with friction dependent on spring force. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 shows a torsional vibration damper  1  as a divided flywheel with a first disc part  2  serving as a flywheel mass and having a starting gear ring  2   a  which is attached radially on the outside and is fixed on the drive side by circumferentially distributed screws  3  and reinforcement or washer discs  3   a  on a drive shaft (not shown) of an internal combustion engine, and a second disc part  9  connected to the gearbox side through a flywheel mass  4  on which a clutch (not shown) can be fitted by means of a centering or locator bolt, as well as the suspension device  5  which is mounted in the force path between same and which is acted upon by the axially aligned bolts  6 , 7  which are connected to the disc parts  2 ,  9 , with preferably six coil springs  8  which are spread out over the circumference and oppose rotation of the two disc parts  2 , 9 . 
     The disc part  2  is centered on a bearing bush  10  which is likewise non-rotatably connected to the drive shaft by means of a radially outwardly oriented flange part  11  and the screws  3 . A rotatably mounted stop ring  13  of L-shaped cross-section is drawn onto a shoulder  12  of the bearing bush  10  which is formed radially on the inside and spaced axially from the flange part  11  whereby the disc part  9  is placed against the stop ring by means of a tubular flange part  17  formed on the inner circumference axially in the direction of the disc part  2  with the interposition of a sliding bush  14 . Six rivets or bolts  6 , 7  circumferentially spaced, preferably on each disc part are riveted as biasing means or sockets for the suspension device  5  on the two disc parts  2 ,  9  with the interposition of the ring disc like intermediate parts  15 ,  16  wherein these have windows  18 , 19  shaped and dimensioned to receive the energy accumulators  8 , and the intermediate part  16  attached to the disc part  9  holds the flywheel disc  4  radially outwards by means of further rivets  20  spread out over the circumference, whereby other connecting means such as for example screw bolts and the like can also be used. The bolts  6 ,  7  extend axially so far that they do not contact one another and only bias the two socket parts  21 , 22 . The heads  6   a  ,  7   a  of the rivets  6 ,  7  are dimensioned with regard to their diameter so that a play-free engagement or, for producing an undamped small angular area about the neutral position of the compression of the energy accumulator  8 , an engagement with play in the openings  25  of the suspension device  5  is ensured whereby the round openings  25  are each formed by a biasing device  23  of the one socket part  21  formed as a half dish and stressing the entire width of the suspension device  5 , and a circumferentially following biasing device  24  of the socket part  22  which mirrors the biasing device  23 . With relative rotation of the two disc parts  2 ,  9  against each other the annulus of rivets thereby entrains with the bolt  7  the socket parts  21  and biases the energy accumulator  8  by means of the biasing devices  23  for example in the positive turning direction and the bolts  6  of the disc part  9  remain stationary or bias the socket part  22  by means of the biasing means  24  against the action of the energy accumulator  8  in the negative sense and vice versa whereby the two half shells  23 ,  24  are separated from each other to an extent corresponding to the turning angle. The biasing devices  23 ,  24  have for holding the energy accumulators  8  in the circumferential direction, opposite the half shells forming the openings  25 , contact bearing faces  26 ,  27  complementary to the ends of the energy accumulators—seen more clearly in FIG.  2 . Circumferentially continuous wire rings  28 ,  29  are provided at the outer circumferences of the socket parts  21 ,  22  for reinforcing these in the event of high centrifugal forces and these wire rings are inserted in circumferential grooves  30 , 31  formed in the socket parts  21 ,  22 . 
     A base amount of friction of the torsional vibration damper  1  is achieved through the axial biasing of the two socket parts  21 ,  22  whereby friction torque is built up at the contact points thereof. In addition, an actual friction device  32  with a friction disc  37  is mounted radially outside of the suspension device  5 . The friction disc  37  is advantageously inserted (as shown in FIG. 1) or, as an alternative (not shown), snap-fitted by axially protruding studs rotationally secured on the disc part  9 . A stop plate  33  is secured in the area of its outer circumference by means of circumferentially distributed screws  34  on an axial circumferential projection  35  of the disc part  2  on the drive side, whereby a radially inwardly open groove  36  is formed between the disc part  2  and the stop plate  33 . The friction disc  37  is placed in this groove and biased by means of the diaphragm spring  38  which is placed against the disc part  2 . The friction control disc  40  has an external tooth profile engaged in an internal tooth profile with internal teeth  39  formed on the inner circumference of the friction disc  37 . The friction control disc  40  further has internal teeth  41  making a positive locking connection with screws  42  which are distributed over the circumference and are aligned axially in the direction of the disc part  2  and which are fixed by means of threaded bushes  43  and nuts  44  in the flywheel mass  4  on the output side whereby the friction control disc  40  is pushed against the heads  42   a  of the screws  42  by means of the plate spring  45  which is inserted in a groove  46  between the friction disc and stop disc  33 . To delay the onset of friction, an angular play can be provided either between the friction disc  37  and friction control disc  40  or between the internal teeth  41  of the friction control disc  40  and the screws  42 . As an alternative to the foregoing illustrated embodiment of FIG. 1, the friction device  32  can be designed so that the friction control disc  40  engages by axially protruding teeth, preferably formed on its outer circumference, in recesses of one of the two disc parts, preferably in the force applying component—by way of example in the divided flywheel connected to the drive shaft—whereby the friction generating device  32  can be mounted radially outside or radially inside the suspension device. It can be further advantageous to make the friction force dependent on the force being applied to the energy accumulators  8 , thus in dependence on the spring force in the instance where the energy accumulators  8  are coil compression springs. 
     FIG. 2 shows a suspension device  5  according to the invention having the socket parts  21 ,  22  whereby the socket part  22  for clarity is only shown in section. Both socket parts  21 ,  22  are identical and are fitted into each other whereby the openings  25  are formed for biasing through the bolts (not shown) of the disc parts. Each of the socket parts  21 ,  22  forms in the number of the energy accumulators  8  which can be stored—in certain cases spaces can be left unoccupied for the energy accumulators—a biasing device  23 ,  24  which has half shell shaped openings  23   a ,  24   a  which in the neutral position form the openings  25  and have shaped portions  23   b ,  24   b  complementary to the bolts, and on the opposite side in the circumferential direction have contact bearing faces  26 ,  27  for the energy accumulators  8  which correspond to the width of the entire suspension device  5  and thus project axially into each other socket part  21  or  22  whereby for the relevant energy accumulator  8  a contact bearing face  26 , 27  is formed corresponding to its cross-section whereby a contact bearing face  26  and a contact bearing face  27  biases each energy accumulator  8 . The socket parts  21 ,  22  are rotatable relative to each other against the action of the energy accumulators  8 . The maximum turning angle is determined by stops  50 ,  51  projecting circumferentially into the pockets  52 ,  53  for holding the energy accumulators whereby the stops block the turning in the event of the maximum predetermined turning angle and bypass the damping device. The stops  50 ,  51  conform in cross-section to the contour of the energy accumulator  8  so that these are supported radially outwards in the event of high centrifugal forces. The biasing devices  23 ,  24  of the socket parts  21 ,  22  are housed radially outwards by an outer support  54  and radially inwards by an inner support  55  which are mounted in a common plane. The outer support  54  has approximately the cross-section of a quarter circle so that when the socket parts  21 ,  22  are fitted together roughly the cross-section of a semicircle is formed with radially outwardly guided circular arc or profiled section which is chamfered at the outer edges. The inner support  55  is formed on its inner circumference as a flat cylinder face so that the suspension device  5  can thereby be housed and centered. The outer circumference of the inner support  55  is provided in the pockets  52  with conical chamfers  56  which, when the socket parts  21 ,  22  are fitted together, are approximately barrel-shaped and in which the energy accumulators  8  can be fitted whereby these are supported radially. 
     The receiving faces  26 ,  27  of the socket parts  21 ,  22  can advantageously be 70% or more of the area of the energy accumulator cross sections and, therefore, the ends of the energy accumulators  8  need not be ground as exactly flat as in conventional dampers or indeed grinding can be omitted completely. The inclination of the receiving faces  26 ,  27  relative to the circumferential direction is preferably selected in such a way that it conforms to the inclination of the ends of the energy accumulators  8 . 
     In the illustrated embodiment, the energy accumulator  8  is formed as a coil compression spring with windings  8   a ,  8   b  of smaller and larger diameter whereby, seen in the installation position, the small windings  8   a  can be inserted relative to the socket parts  21 ,  22  radially outwards with compression into the large windings  8 b and radially inwards—if the stops do not lock this turning angle—pass into a block. The advantage of this spring assembly is the greater compression length since the compression path at the outer circumference is greater than at the inner circumference. In order to block the rotation of the springs  8  along their longitudinal axes the spring ends are inserted in the indentations  26   a  ,  27   a  of the contact bearing faces  26 , 26 . 
     Advantageously the suspension device  5  is made from a plastic material whereby injection moulding processes are preferably used although a design of metal can also be advantageous. 
     FIG. 3 shows a partial view of a torsional vibration damper  101  as a divided flywheel which is designed basically in the same way as the torsional vibration damper  1  in FIG. 1 but with the following modified design features: 
     The disc part  102  supports as the flywheel mass on the drive side a ring-disc like sheet metal part  102   b  fixed radially outwards by means of circumferentially distributed screws, rivets or the like and shaped round into a bead  102   c  on its outer circumference in the axial direction and radially outwards approximately round 180 degs. in the direction of the starting gear ring  102   a  which is attached radially outside on the disc part  102  in order to increase the moment of inertia. The sheet metal part  102   b  forms on the inner circumference with the disc part  102  by means of an axially impressed shoulder  102   d  a circumferential groove  136  in the friction control disc  140  and a plate spring  138  which is supported between the disc part  102  and the friction control disc  140  whereby friction torque is produced when the friction control disc  140  turns relative to the sheet metal part  102   b . To this end, the friction control disc  140  is connected by means of teeth  141  which can provide a certain amount of play to produce a delayed friction, with the disc part  109  which has on the outer circumference tongues  109   b  shaped round axially accordingly in the direction of the disc part  102 , to the disc part  102  whereby the proposed friction torque is established during corresponding relative rotation of the disc parts  102 , 109 . The circumferentially distributed tongues  109   b  are inserted at their bending radius  109   a  into corresponding recesses  104   b  of the flywheel mass  104  on the output side connected to the disc part  109  and having means  104   a  for holding a clutch (not shown). 
     The reinforcement  128  is in this embodiment designed so that it axially encloses both support parts  154   a ,  154   b  and is drawn radially inwards at the flanks. The shape of the reinforcement is designed so that the two support parts can turn circumferentially relative to each other without problem whereby friction of the support parts  154   a ,  154   b  during relative rotation can be set on the reinforcement whereby a hysteresis provided in addition to the friction device can be effected. 
     The journalling of the disc part  109  is effected directly through the interposition of an anti-friction bearing bush  114  on the disc part  102  and the two disc parts are formed round axially facing one another. For axially spacing out the two disc parts  102 ,  109  the reinforcement disc  180  which is screwed to the drive shaft by means of the screws  103  which also undertake the task of fixing the disc part  102  on the drive shaft is shaped round correspondingly axially to form a radially inwardly directed extension  180   a.    
     The suspension device  105  which serves as a holding device for the energy accumulators  108  has at its outer circumference a circumferential reinforcement  128  which is adapted to the shape of the two outer supports  154   a ,  154   b  and engages over same and which counteracts the centrifugal forces at high speeds and/or can serve as thermal protection whereby the material must be able to withstand tensile stresses and/or to be thermally stressed according to these conditions and/or have heat-radiating properties. Furthermore the reinforcement  128  can be mounted on the outside support  154   a ,  154   b  by exerting initial axial stressing so that the friction force can thereby be set between the two and a basic friction can be established for the torsion vibration damper  101 . 
     FIG. 4 shows a divided flywheel  201  similar to the embodiment  101  of FIG.  3  and fitted in addition with a circumferentially restricted slip clutch  256 . The flywheel mass  204  on the output side is rotatable circumferentially relative to the disc part  209  on the output side against the friction torque caused by the friction discs  258 ,  259  relatively in the area of the turning angle defined by the stops  257  in which the bending radii  209   a  of the side disc  109  are guided. The flywheel mass  204  is to this end housed between two ring disc like metal plates  260 ,  261  and supported against the friction discs  258 ,  259  attached to the plates  260 ,  261  whereby the plate  260  is non-rotatably connected to the disc part  209  by means of the bolts  206  biasing the suspension device  205  and the plate  261  is suspended by means of teeth  262  which can be provided with play to form a two-stage slip clutch  256 , in the tongues  209   b  which have stops  209   c  for the axial support of the metal plate  261 . 
     The disc part  309  of the embodiment of a divided flywheel  301  shown in FIG. 5 is formed as a complete casting so that especially the radially outer part is inserted as flywheel mass  304  and the friction control disc  340  by means of the inner teeth  341  is inserted in circumferentially spaced apart extension arms  309   a  aligned axially in the direction of the disc part  302 . 
     The disc part  309  is journalled as in the previous embodiments in the disc part  302  and it is axially expanded in the area of the bearing socket  312  and circumferentially spaced assembly openings  303   a  are provided for fixing the flywheel  301  on the drive shaft by means of the screws  303 . 
     In the embodiment of a divided flywheel  401  shown in FIG. 6 the disc part  402  is reshaped axially to form a flywheel mass  488  in the direction of the disc part  409  which in turn is formed as a casting and is extended over its radial outer circumference. The friction device  432  is formed by a friction control disc  440  which fits radially close outside the screws  403  for fixing the disc part  402  and inside the suspension device  405  and by the plate spring  438 . The friction control disc  440  is housed, with a radially inwardly aligned attachment  440   a , in radially aligned tongues  481  of the reinforcement flange  480  and is biased by a diaphragm spring  438  which is inserted between the disc part  402  and friction control disc and engages by inner teeth  438   a  likewise in the tongues  481 . The friction control disc  440  is connected in the disc part  409  by spur gearing  440   b  which engages with keyed connection in suitably recessed openings  409   a  of the disc part  409 . The teeth can be provided with play between the parts  481 ,  438   a  and/or  440   b ,  409   a  to produce delayed friction. 
     A torsional vibration damper, especially in the form of a divided flywheel  501  can—as shown in FIG.  7 —have two suspension devices  505   a ,  505   b —as described in the previous embodiments—radially spaced from each other whereby a torque intensification can be achieved by increasing the number of energy accumulators  508   a ,  508   b  and/or a two-stage damping device can be created. When creating a two-stage damping device, the biasing devices—which cannot be seen but are denoted in FIG. 2 by reference characters  23 ,  24 —or the energy accumulator sockets ( 26 ,  27  in FIG. 2) of the radially inner or radially outer suspension device  505   a ,  505   b  can be provided with circumferential play so that the biasing of the corresponding energy accumulators  508   a ,  508   b  only takes place in the event of greater angular displacement between the disc parts  502 ,  509 . A restriction of the diameter of the bolts  506   a  ,  507   a  or  506   b ,  507   b  is also possible to produce turning play. 
     In the same way—as shown in FIG.  8 —a divided flywheel  601  can be proposed which has as a first damping device a suspension device  605   a  with preferably six circumferentially spaced apart short coil compression springs  608   a  and a second damping device  605   b  with long arcuate springs  608   b  extending over a larger area on the outer circumference of the flywheel  601 , as known per se from DE OS 37 21 711 for example and which are housed with the interposition of an anti-wear shell  687  provided on the outer circumference of the curved springs  608   b , in a radially inwardly circumferentially open chamber  686  formed by the disc part  602  and a radially inwardly directed flange part  602   b  welded to an axially aligned connecting part  602   a  shaped round axially on the outer circumference of the disc part  602 . The two damping devices  605   a ,  605   b  are thereby connected in series in a sense such that the one end of the curved springs  608   b  of the damping device  605   b  on the circumferential side, viewed from the drive side, is first biased in the circumferential direction by means of axially shaped biasing devices  606   b  and  607   b  provided in the disc part  602  and the flange part  602   b , and the radially aligned flange  688  engaging through the radially inwardly open chamber  686  into the other end of the curve springs  608   b  on the circumferential side by means of biasing devices  688  formed as radially aligned extension arms directly biases with the bolts  607  on the drive side acting as biasing devices the damping device  605   a  which acts in a known way on the disc part  609 . The flange part  688  and the disc part are rotatable relative to each other in the turning angle range of the damping devices  605   a ,  605   b  whereby this is restricted mechanically by the stops  651 —see also FIG. 2, indices  50 ,  51 —and the flange part  688  is centered on the reinforcement part  680 . The friction disc  640  acting on the damping device  605   b  engages by teeth  641  with keyed engagement preferably with turning play in openings  688   b  in the flange part  688  provided therefor and is supported by means of the axial action of the plate spring  648  between the flange part  602   b  and the friction control disc  640  conically on the flange part  688 . The basic friction which acts on the damping device  605   a  takes place through the contact points  621 ,  621   b ,  621   c  of the two socket parts  621 ,  622  wherein the friction can be selected in this area by the reinforcement  628 . 
     The friction control disc  740  of the friction device  732  of the divided flywheel  701  shown in FIG. 9 is inserted axially between the suspension device  705  and the disc part  702  and is connected positively by the outer teeth  741  with the axially aligned extension arms  709   a  whereby rotational play can be provided for producing delayed friction. The friction control disc  740  is entrained by the extension arms  709   a  so that with relative rotation between the disc parts  702 ,  709  a friction torque is produced between the friction control disc  740  and the disc part  702 . This friction torque can be formed dependent on spring force, that is the friction torque increases with the force being applied to the coil springs  708 . 
     To this end, FIG. 11 shows in a sectional view the disc part  702  with the biasing bolt  707  fixed thereon which engages in the biasing device  723  on the drive side of the suspension device  705 . The friction control disc  740  is mounted between the suspension device  705  and the disc part  702 . During relative rotation between the two disc parts  702 , 709  the energy accumulators  708  are compressed whereby a counter force occurs in dependence on the spring force between the biasing devices  723  of the suspension device  705  and the biasing bolts  706 , 707 . The contours of the biasing means  707 ,  723  are formed so that a ramp  723   a  is formed between same along which as a result of the spring force arising on the circumferential side an axial component of this force is introduced from the suspension device  705  into the friction control disc  740  whereby as the spring force increases so a higher contact pressure force acts on same and the friction torque is thereby increased. 
     FIG. 10 shows a divided flywheel  801  with a clutch  888  which consists of the disc part  809  with the flywheel mass  804  forming the contact pressure plate  889 , as well as the clutch disc  892  which is mounted axially between the contact pressure plate  889  and the pressure plate  890  and establishes by means of teeth  892   a  the connection with the gearbox (not shown) and supports radially outwards friction linings  892   b , the clutch cover  893  on which the clutch plate spring  895  is mounted through the socket device  894  and which biases the pressure plate  890  through the cams  890   a , whereby the clutch cover  893  is fixedly connected to the flywheel mass  804  on the outer circumference thereof. 
     The suspension device  805  which acts between the disc parts  802 ,  809  in the circumferential direction is mounted as the damping device axially between the disc part  802  and a further disc part  897  which is housed with the disc part  802  by means of screws  803  and centered thereon whereby the energy accumulators  808  are biased on the drive side by axially protruding radially aligned biasing devices  806 ,  807  formed from disc parts  802 ,  897 , and on the output side by axially extended extension arms  893   a  of the clutch cover  893 . The extension arms  893   a  thereby engage radially outside of the energy accumulators  808  in suitably provided openings  854   a  of the outer supports  854 ,  855  and during relative rotation between the disc parts  802 ,  809  entrain the suspension device  805  whereby the energy accumulators  808  are compressed since they are held firm by the biasing means  806 ,  807  on the drive side and vice versa. For small turning angles it is possible as in the other embodiments to provide a turning play—here through circumferentially expanded openings  854   a —in the attachment of the suspension device  805  in which the damping device is inoperative. 
     The friction control disc  840  is in this embodiment provided radially inside the suspension device  805  with the disc parts  802 ,  897  and is controlled on the output side by means of cams  804   a  provided axially in the direction of the drive side on the disc part  809  and which are guided through the entire turning play in circumferentially recessed openings  897   a . The friction control disc  840  and the plate spring  841  are housed on these cams  804   a  by means of the inner teeth  840   a ,  841   a  whereby the friction control device  840  is supported by means of the diaphragm spring  841  on a stop ring  842  which is riveted to the disc part  802  in the radial outer area. 
     The invention is also not restricted to the embodiments of the description. Rather numerous amendments and modifications are possible within the scope of the invention, particularly those variations, elements and combinations and/or materials which are inventive for example through combination or modification of individual features or elements or process steps contained in the drawings and described in connection with the general description and embodiments and claims and which through combinable features lead to a new subject or to new process steps or sequences of process steps insofar as these refer to manufacturing, testing and work processes.