GB2184515A - Device for reducing vibrations excited in a motor-driven drive line - Google Patents

Abstract

Two flywheel elements (1,2) are capable of rotation relative to one another against springs (3) which are arranged between annular disc-shaped abutment parts (40, 50, 51). The one abutment part (40) is frictionally coupled to the one flywheel element (2) by means of a clutch (41) and is only capable of limited rotation relative to this flywheel element (2). The other abutment part (50, 51) is connected to the other flywheel element by means of another clutch (53), the frictional contact of which is greater than in the case of the previously mentioned clutch (41), and this other abutment part is capable of unlimited rotation relative to this flywheel element (1). <IMAGE>

Description

SPECIFICATION Device for reducing vibrations excited in a motor-driven drive line The invention relates to a device for reducing drive line vibrations excited byan engine, in particular a splitflywheel, having two device or flywheel elements which are arranged mutually on the same axis axis and are coupled to one another in a driven manner by means ofaspring mounting, one of which device or flywheel elements is connected or can be connected to the engine and the other is connected orcan be connected to the drive line, the abutmentofthespring mountingallocatedtothe one device or flywheel element being arranged on an abutment part which is frictionally connected to this device or flywheel element in a driven manner without limitation of the rotational capacity relative to one another, and the strength ofthefrictional contact being greaterthan the maximum torque of the engine.

Such a device or a corresponding flywheel is the subject-matter of the earlier Patent Application No 8603567 in which a frictional clutch is provided between the elements of the device. Another device ofthis general kind is also disclosed in German PatentApplication No P3519912.1.

The advantage of the corresponding arrangement is that a good degree of comfort can be achieved.

The drive system is adapted in such a way that the resonant frequency if at all possible lies somewhat below the idling speed ofthe engine. Consequently, the resonant frequency can be excited virtually only when starting the engine. This is equivalenttosaying that travel operation is performed in the so-called hyper-critical range, ie. the frequency ofthe vibrations occurring in travel operation is generally considerably higher than the resonant frequency.

Consequently, only relatively low vibrational amplitudes occur between the device or flywheel elements during travel, a transmission ofthe vibrationsfrom the engine to the drive line orvice versa being prevented by the spring mounting between the flywheel elements. If, when starting the engine, the resonant range ofthe device or ofthe flywheel is traversed, the device orflywheel elements execute comparatively large displacement movements relative to one anotherwhich are effectively da m ped, however, beca u se th e fo rces transmitted by the spring mounting between the device or flywheel elements exceed the strength of the frictional contact, so that the abutment part frictionally connected to the one device orflywheel element slips relative to the said element.

As long as the forces transmitted between the device orflywheel elements by means of the spring mounting -such as during the travel of a veh;cle - are lower than the strength of the frictional contact the same cannot exert any damping effect. This is admittedly especially desirable in the case ofthe relativelysmail displacement vibrations such as occur in the hypercritical range. However, there are situations in which larger relative movement between the device or flywheel elements can occur even outside the resonant frequency of the drive line.

this isthe case,forexample, in the load change between coasting and drive of a vehicle. As, however,theforces occurring in such a load change are often less than the strength offrictional contact, a damping of the vibrations associated with the load change is not readily possible.

It is therefore the object of the invention to design the device or the flywheel of the type outlined above in such a way that the relative movements occurring between the device or flywheel elements are also already effectively damped when the forces acting between the device and the flywheel elements in these relative movements are weaker than the maximum enginetorque, butstrongerthan a thresholdvalueto be specified.

According to the invention, there is provided a device for reducing vibrations excited in a motor-driven drive line, including in particular a split flywheel, having two device or flywheel elements which are arranged mutually on the same axis and are coupled to one another in a driven manner by means of a spring mounting, one of which device or flywheel elements is connected or can be connected to the engine and the other is connected or can be connected to the drive line, and preferably also having a frictional clutch which is active between the device or flywheel elements and is effected by clearance, in which the abutment of the spring mounting, which abutment is allocated to one device orflywheel element, is arranged on an abutment part which is frictionally connected to this device or flywheel element in a driven mannerwithout limitation of the rotating capacity relative to one another, with the force ofthe frictional contact being greaterthan the maximum torque ofthe engine, wherein the abutment of the spring mounting allocated to the other device of flywheel element is arranged in another abutment partwhich is frictionally connected to the other device orflywheel element but with limited rotational capacity, and the strength ofthisfrictional contact is a smallervalue than the frictional contact between the one device and the flywheel element and the first-mentioned abutment part.

Thus, on the basis ofthe invention, one of the abutment parts can yield or disconnect even with comparatively small torques, and consequently damp relative movements between the device or flywheel elements comparatively earlier. Onlywhen there are very strong torques or extremely high vibration amplitudes of the relative movements between the device or flywheel elements does the other abutment also yield with corresponding damping effect.

Thus, the invention ensures that a progressive damping ofthe relative movements ofthe device or flywheel elements is ensured, ie. the damping increases with increasing relative movements.

According to a preferred embodiment ofthe invention, the progressivity can be improved further by each abutment part being frictionally connected to the allocated and/orthe respective other device or flywheel element through one or more clutches affected by clearance, the clutches having in each case a different clearance so that, when there is correspondingly strong relative movement ofthe device orflywheel elements, the effects of the clutches come into action successively with corresponding increase of the respective frictional contact between abutment part and device or flywheel element.

In a particularly advantageous embodiment of the invention, annular discs, radially overlapping one another are arranged as abutments, these discs having, in the overlap region, cut-outs or windows extending in the peripheral direction and overlapping one another, which accommodate helical compression springs which are arranged in the peripheral direction and the face ends of which-seen in the axial view ofthe helical compression springs-in each case pass through the disc planes, andtheannulardiscsformingthe one abutment are frictionally connected in the region of their inner periphery by means of coupling laminae totheonedeviceorflywheel element and the annular d iscs forming the other abutment a re frictionally connected in the region oftheirouter periphery by means of coupling laminae to the other device orflywheel element. This achieves a space-saving and easily assembled construction.

At the same time, it is expedient if the annula r discs forming the one abutment have projections on their inner periphery- for example radial projections -which interact in the manner of stops, with clearance in the peripheral direction, with counter-projections on the one device or flywheel elementora hubpartofthesame,oriftheannular discforming the other abutment have on their outer periphery corresponding projections which interact in the manner of stops, with clearance in the peripheral direction, with counter-projections which are arranged on the other device or flywheel element ora peripheral rim ofthesame. In this way, the limited mobility of one of the abutment parts with respect to the allocated device or flywheel element can be ensured byverysimplemeans.

Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which: Figure Ito 6shows schematic representations of various embodiments ofa split flywheel constructed in accordance with the invention, Figure 7shows a diagramm to explain the dependency between the torques (M), acting orto be overcome between the flywheel elements ofthe embodiment of Figure 5, as a function of the relative deflection (ack) oftheflywheel elements to one another, and Figure 8and 9 show axial sectional views of flywheels according to the invention according to the design arrangement shown in Figure 5.

In Figure 1, the two flywheel elements 1 and 2 are shown schematically as heavy bodies which are supported or coupled relative to one another by means of a spring mounting 3. The spring mounting 3 is clamped between two abutments 4,5, which in each case are frictionally connected by means of a slip clutch 6 and 7, respectively, to the respectively allocated flywheei element 1 or 2. The slip clutches 6 and 7 arethus arranged in series with the spring mounting 3.The slip clutches 6 and 7 operate with differentfrictional contacts, ie.the slip clutch 6 breaks away or disconnects even at relatively small torques, which the slip clutch 7 does not yield until there aretorques greaterthanthe maximumtorque ofthe engine. The abutment4 is arranged with limited mobility with respect to the flywheel element 2, which is preset by stops 8, or by their distance. The abutment 5, on the other hand, can in principle move in an unlimited mannerwith respect two the flywheel element 1 when the slip clutch 7 breaks away.

In travel operation, the flywheel elements 1 and 2 execute relative movements with respect two one another, which are reproduced in Figure 1 as approach or withdrawal oftheflywheel elements 1 and 2 towards or away from one another.

Insofar as only slight relative movements, ie.

vibrations of low amplitude, occur between the flywheel elements 1 and 2, neither of the slip clutches 6 and 7 will break away, so that the flywheel elements 1 and 2 can move towards one another virtually undamped.

With strongervibrational amplitudes and correspondingly highertorques acting between the flywheel elements 1 and 2, first of all the slop clutch 6 breaks away, ie. the abutment4 moves relative to the flywheel 2. Consequently, the relative movement between the flywheel elements 1 and 2 is damped along a greater or lesser travel distance by the frictional contact ofthe slip clutch 6.

With even strongervibrational amplitudes, the travel distance available to the abutment4 between the stops8 is used up, ie.the abutment4comes up against the stops 8. With corresponding apportionment of the frictional contact ofthe slip clutch 7,the latterwill then break away and, with damping of the relative movements oftheflywheel elements 1 and 2, limitthe maximum torque transmitted between the flywheel elements 1 and 2.

The arrangement according to Figure 2 differs from that according to Figure 1 merely in that between the abutments 4 and 5 is arranged aslip clutch 9 which is affected by clearance and which in each case only becomes active when the abutment5 has used up a clearance available to it between stops 10. The slip clutch 9 thus acts in the manner of a stiffening ofthespring mounting 3 when the abutments 4 and 5 are deflected to a greater extent relative to one another in one direction orthe other.

The distances between the stops 8 and 10 and the frictional contacts ofthe slip clutches 6 and 9 are expediently apportioned such that the slip clutches only break away successively when there is a correspondingly strong relative movement ofthe flywheel elements 1 and 2.

The embodiment according to Figure 3 differs from that according to Figure 1 in that the abutmentS is frictionally coupled buy a slip clutch 11 affected by clearance to the flywheel element 2 as well, the slip clutch 11 only becoming active when a movement space given to the abutment5 between stops 12 has been used up.

In the embodiment according to Figure 4, it is provided furthermore that the abutment 4 is, compared with Figure 3, additionally frictionally connected by means of a slip clutch 13 affected by clearance to the flywheel element 1, the effect ofthe slip clutch 13 not coming into action until the abutment 4 has used up a movement space remaining between the stops 14.

The distances of the various stops 8,12 and 14and the torques transmitted by the respective slip clutches 6, 11 and 13 are expediently apportioned in such a way that the said slip clutches only break away successively when there is correspondingly strong deflection oftheflywheel elements 1 and 2 relative to one another, to achieve a correspondingly progressive damping ofthe relative movements of the flywheel elements 1 and 2.

The embodiment according to Figure 5 differs from that preceding embodiments in that the abutments 4 and 5 are additionallyfrictionally coupled to the respectivelyallocatedflywheel elements 1 and 2 by slip clutches 22 and 15, respectively, affected by clearance, which in each case only become active after using up a movement clearance preset by stops 16 or 17 for the respective abutments 4 or 5. Heretoo,thearrangementis expediently again adpated such that the slip clutches break away successively when there is correspondingly strong deflection of the flywheel elements 1 and 2 relative to one another until,with very large relative movements, all the slip clutches 6, 7,14 and 15 slip.

It can be seen from Figure 6 that the arrangement according to Figures 4 and 5 can also be combined.

In some cases, in addition, still another arrangement according to Figure 2 is possible. However, for reasons of clarity, this has not been shown in Figure 6.

The diagram in Figure 7 shows in detail the functional mode of the flywheel shown in Figure 5. In this diagram,thetorque M active ortransmitted between the flywheel elements 1 and 2 is shown as a functions of the displacement or rotation (4) ofthe flywheel elements 1 and 2 relative to one another.

Let the flywheel first be located in the centre position shown in Figure 5.

lftheflywheel elements 1 and 2 are now to be rotated relative to one another- in the representation of Figure 5 in an approach directionfirst of all only the resistance of the spring mounting 3 must be overcome, which sets up an increasing counter-moment against an increasing relative rotation of the flywheel elements 1 and 2 according to the curve section A. Then the slip clutch 6 breaks away and slips according to a curve section B until the clearance available to the abutment 4 between the stops 16 has been used up. Then, with further rotation, the spring mounting 3 is increasingly tensioned according to the curve section C until the slip clutch 14 also slips according to the curve section D.As soon as the clearance availabletothe abutment 4 between the stops 8 has been used up, the spring mounting 3 is in turn increasingly tensioned according to the curve section E until the maximum torque between the flywheel elements 1 and 2transmittable bytileeslipcGutch 7 actsandthe slip clutch 7 slips according to the curve section F.As soon as the clearance available to the abutment 5 between the stops 17 has been used up, the spring mounting 3 is once again increasingly tensioned according to the curve section G until the resistance ofthe slip clutch 15 is also overcome according to the curve section H.

As soon asthe relative movement between the flywheel elements 1 and 2 in the specified direction has cometo a standstill, the spring mounting 3 can in turn relax according to the curve section 1. In some cases, the previously described sequence of movements can the proceed in the reverse direction.

It must be noted herethatthe abutments 4 and 5 in each case assume an end position between the stops 8,16 and 17 and can consequently be displaced in the reverse direction along relatively large travel distances B', D' and F', respectively. Moreover, the same relationship described applies analogously in the relative displacement of the flywheel elements 1 and 2 in the reverse direction. With a renewed direction reversal, the abutments 4 and 5 can, of course, move between the stops 8,16 and 17, again along relatively large travel distances B", D", which have the same length as the travel distances A', B'.

Figure 8 shows an axial section of constructional embodimentoftheflywheel accordingtothe invention corresponding to the design arrangement shown in Figure 5.

The flywheel element 1 is connected in a driven mannertotheengine (notshown).Theflywheel element 2 is rotatably mounted on the flywheel element 1 by means of a bearing arrangement 18 and can be connected in a driven manner by a clutch (not shown) to the input shaft ofa drive line or a vehicle transmission orthe like (also not shown).

Between the flywheel elements 1 and 2 there remainsanannularspace 19whichservesto accommodate the spring mounting 3 and its abutments, which are each frictionally connected to a flywheel element 1 and 2, respectively, as explained further below.

The one abutment is formed by an annular disc40 which has on its inner periphery radial projections or recesses on a hub part 21 firmly connected by pins 20 to the flywheel element 2. In this arrangement, the recesses and projections are arranged on the hub part 21 and the ann u lar disc 40, respectiveiy, with adequate clearance such that the annulardisc40 has limited rotational capacity relative to the flywheel element 2, forexample by an angle of 20. These projections and recesses correspond to the stops 8 ofthe flywheel element 2 in Figures 1 to 6, interacting with the abutment part 4.

Theannulardisc40 isfrictionallyconnected inthe region of its inner periphery by means of a clutch arrangement 41 to the flywheel element 2 and the hub part 21.The coupling arrangement41 is progressively designed, ie. the strength ofthe frictional contact increases with increasing deflection ofthe annular disc 40 from a centre position relative to the flywheel element 2. For this purpose, the annular disc 40 is frictionally connected to friction laminae 42 fixed relative to the flywheel element 2. The friction laminae 42 always set up a given resistance against a displacement of the annular dise 40 relative to the flywheel element 2 or the hub part21.

Furthermore, the annular disc 40 is positively connected to an annular laminae, but with clearance, which is less than the movement clearance ofthe annulardisc40 relative to the hub part 21 ortothe flywheel element2. In addition,theannularlaminae 43 has on its outer periphery bent-over portions 43' which engage in lateral recesses on the annular disc 40. Atthe same time,the recesses on the annular disc 40 have a larger extent in the peripheral direction than the bent-over portions 43' to allow the annular lamina 43 the required clearance relative to the annulardisc40. The annularlamina43 interacts with other annular laminae 44, which establish a frictional connection between the flywheel element2 orthe hub part21 andtheannularlamina43.

If, therefore, the annular disc 40 is displaced relative to the flywheel element 2, first of all merely the frictional contact which is generated by the friction Iaminae 42 has to be overcome. With larger deflection angles, then the frictional contact between the annular lamina 43 and the hub part 21 orthe flywheel element 2 has to be additionally overcome.

In the vicinity ofthe outer periphery, the annular disc40 has windows or apertures 45 extending in the peripheral direction in which helical compression springs 3 serving as a spring mounting are inserted with our without pretension.

Arranged at the side ofthe aperture region ofthe annulardisc40 are annularwebs 51 whichfortheir partarefitted - by means of pins orthe like -to an annular disc 50 which for its part is arranged concentricallytotheannulardisc40. In the annular webs 51 are arranged apertures 52 corresponding to theaper.ures4S ofthe annulardisc40 and accommodating areas of the helical compression springs 3.

In a central position ofthe annulardiscs 40 and 50, the apertures45 and 52 lie oppositeand in alignment with one another, so that the two ends of each helical compression spring 3 bear in each case against the radial edges ofthe apertures 45 and 52. if annular discs 40 and 50 are deflected out of their centre position relative to one another, the apertures 45 and 52 can only overlap partially, with the consequence thatthe helical compression springs 3 are increasingly compressed, the one end of each helical compression spring bearing only against a radial edge organ aperture 45 and the other ends only against radial edges ofthe apertures 52.Thus, the helical compression springs 3 are increasingly tensioned ifthe annulardiscs 40 and 50 are deflected relative to one another more or less far in one dimation orthe other.

At its radial outer edge, the annular disc 50 is frictionally connected merely - by means of a clutch arrangement 53 - to the flywheel element 1, ie. when the frictional contact is overcome, the annular disc50 can be rotated as far as desired relative to the flywheel element 1.

The clutch arrangement 53 is, in turn, progressively designed, ie. a smallerfrictional intact is effective at small deflection angles r,ttfleen annular disc 50 and flywheel element 1 than at larger deflection angles.

For this, the annular disc 50 is constantly, ie.

independently of the displacement angle, frictionally cou pled by friction laminae 54 and 57 to the flywheel element 1. Thus,this frictional contact is effective at any relative displacement between annular disc 50 and flywheel element 1.

Furthermore, an annularlamina 55 is positively connected to the flywheel element 1 by bent-over portions 55' on the outer peripheryofthe annular lamina 55 being axially displaceable in recesses on the flywheel element 1, but engaging free of clearance in the peripheral direction. In addition, the annular disc 50 is positively connected, butwith clearance,toanotherannularlamina56,which has in the region of its inner periphery windows extending in the peripheral direction, in which the pins 20' or their heads are accommodated with clearance in the peripheral direction.

The annular lamina 56 interacts with other friction laminae 57, so that, after using up the movement clearance of the annular lamina 56 relative to the annular disc 50, in each case an additional frictional contact comes into action between the flywheel element1 and the annulardisc50.

In the arrangement shown, the coupling arrangement 41 has overall a frictional contact which is smallerthan the maximum torque of the engine, whilethecoupling arrangement 53 can, oncethe clearance between the pin 20' and the annular lamina 56 has been used up, only be rotated further if the torque acting exceedsthe maximum engine torque.

The embodiment according to Figure 9 differs from that according to Figure 8 in thattheflywheel elements 1 and 2 are directly coupled to one another through a clutch 60 affected by clearance. Forth is, an annular lamina 61 is positively connected in the peripheral direction, butwith clearance, to the flywheel element 2 by radial projections or recesses arranged on the outer periphery ofthe annular lamina 61 which interact with recesses or projections on the flywheel element 2 by radial projections on the flywheel element 2 and ensure the required clearance. The annular lamina 61 is, for its part, arranged between friction lamina 62 which are mounted on the flywheel element 1.The clutch 60 thus allows the flywheel element 2 a free movement space relative to the flywheel element 1 corresponding to the clearance between the annular iamina 61 and the flywheel element. As soon as the clearance has been used up in one direction orthe other, the - relatively weak -frictional contact ofthe clutch 60 is effective between the flywheel elements 1 and 2.

The clutch 41 acts in the embodiment of Figure 9 between the radially outer region of the annular disc 40 and the flywheel element 1. The annular disc 40 is axially displaceable on the flywheel element 1 and arranged rotatably relative to the flywheel element 1 between friction laminae 42, one of which is directly adjacent to the flywheel element 1, while the other friction lamina is adjoined by an annular lamina 47 which is movable on the flywheel element 1 in the axial direction ofthe same, but is mounted non-rotatably. Arranged between two otherfriction laminae 42, which for their part are arranged between the annular lamina 47 and an annular disc 48, is the annular lamina 43 which engages by bent-over portions 43' on its inner periphery in openings of the annular disc 40.Atthe sametime, the said openings ofthe annulardisc40 are apportioned in the peripheral direction in such a way that the said bent-over portions have a clearance in the peripheral direction. The entire arrangement described is pressed together in the axial direction of theflywheel by means of a spring ring 49, which has an S-like cross-section and is tensioned by its radially inner region againstthe radiallyinner region ofthe annular disc48.

As long as the clearance of the bent-over portions on the annularlamina 43 in the recesses oropenings in the annular disc40 have not yet been used up, the annulardisc40 can, with adequatetorques,be rotated relative to the flywheel element 1 without the annular lamina 43 turning with it. As soon as the clearance between the annular lamina 43 and the annulardisc40 has been used up, the annulardisc40 can only keep rotating by using an increased force relative to the flywheel element 1. In this arrangement, the frictional contact is expediently to beapportioned such that itexceedsthe maximum torque ofthe engine.

The annular disc 50 and the annularwebs 51 are axiallydisplaceablebytheirinnerperipheryand arranged movablyontheflywheel element 2 with clearance in the peripheral direction. Atthesame time, the clearance in the peripheral direction is limited by recesses arranged on the inner periphery ofthe annular disc 50 orofthe annularwebs 51, which interact in the manner of stops with the studs 20. Arranged on either side of the annularwebs 51 arefriction laminae 54, which interact on the one hand with one ofthe annularwebs 51 and on the other hand with an annular part 58 or an annular lamina 55.The annular part 58 is connected by means ofthe studs 20 non-rotatably with the flywheel element 2, while the annular lamina 55 is arranged axially displaceably, but is immovable in its peripheral direction because it clasps the studs 20 by means of recesses on its inner periphery. An annular lamina 55' is arranged between two other friction laminae. This annular lamina 55' has on its outer periphery projections which clasp a pin 20' on one of the annularwebs 51,with clearance in the peripheral direction, so that the annular laminar 55' can be rotated by a limited travel distance relative to the annularwebs 51 . In this arrangement, the movement clearance between the annular lamina 55' and the annularwebs 51 is smallerthan the movement clearance of the annularwebs 51 relative to the flywheel element 2.There then follows, towards the flywheel element 2, another annular lamina 56 which is designed and arranged in the same way as the annular lamina 55. The entire clutch 53 is axially compressed by means of a spring washer 63. As long as the movement clearance between the annular webs 51 on the one hand and the annular lamina 55' has not yet been used up, the annularwebs 51 can, as long as the movement clearance relative to the flywheel element 2 permits, rotate relative to the flywheel element 2 without simultaneous movement oftheannularlamina 55'.After using upthe clearance between the annularwebs 51 andthe annular lamina 55', an increased resistance must be overcome if the annular webs areto rotate relative to the flywheel element 2. Forthis,the maximum frictional contact of the clutch 53 is apportioned such thatthe annularwebs 51 are already displaced relative to the flywheel element 2 when torques act whicharesmallerthanthemaximumtorqueofthe engine.

In some cases, the arrangement described can also be modified by the annulardisc40 having,for example on its outer periphery, projections or recesses which interact with recesses or projections on theflywheel element 1 in such awaythatonlya limited rotation ofthe annulardisc40 relativetothe flywheel element 1 is possible. In this case, this clearance is apportioned such that the clearance availabletotheannulardisc40 relativetothe flywheel element 1 is greaterthan the clearance of the bent-over portions 43' ofthe annular lamina 43 in the recesses or openings ofthe annulardisc40.

If theannulardisc40 isonlycapable of limited rotation relative to the flywheel element 1 in the way described,furthermore the annular disc 50 and the annularwebs 51 are arranged to be capable of unlimited rotation relative to the flywheel element 2, ie. no recesses or projections or the like which could interact with the pins 20 or other elements in the sense of a rotational travel distance limitation are arranged on the inner periphery ofthe annular disc 50 orthe annularwebs 51.

Moreover, in the case ofthe last-described embodiment, the frictional contact of the clutch arrangement 53 is apportioned so as to be greater overall than the maximum torque of the engine, whilethemaximumfrictional contact of the clutch 41 issmallerthanthemaximumenginetorque.

Claims (8)

1. A device for reducing vibrations excited in a motor-driven drive line, including in particular a split flywheel, having two device or flywheel elements which are arranged mutually on the same axis and are coupled to one another in a driven manner by means of a spring mounting, one of which device or flywheel elements is connected or can be connected to the engine and the other is connected or can be connected to the drive line, and preferably also having a frictional clutch which is active between the device orflywheel elements is affected by clearance, in which the abutment ofthe spring mounting, which abutment is allocated to one device or flywheel element, is arranged on an abutment part which is frictionally connected to this device orflywheel element in a driven mannerwithout limitation ofthe rotating capacity relative to one another, with the force of the frictional contact being greater than the maximum torque ofthe engine, wherein the abutmentofthespring mounting allocated to the other device orflywheel element is arranged on another abutment part which is frictionally connected to the other device or flywheel element but with limited rotational capacity, and the strength of this frictional contact is a smaller value than the frictional contact between the one device and flywheel element and thefirst-mentioned abutment part.

2. A device according to Claim 1, wherein at least one ofthe abutment parts is in each case progressivelyfrictionallyconnectedto atleastone device orflywheel element.

3. A device according to Claim 1 or Claim 2, wherein the abutment parts are frictionally connected to one another by a clutch affected by clearance.

4. Adevice according to anyone of Claims 1 to3, wherein each abutment part is frictionally connected to the allocated and/or the respective other device or flywheel elementvia a clutch affected by clearance.

5. A device according to any one of Claims 1 to 4, wherein there are arranged as abutments annular discs, radially overlapping one another and having, in the overlap region, cut-outs or window extending in the peripheral direction and overlapping one another, which accommodate helical compression springs which are arranged in the peripheral direction and the face ends of which as seen in axial view ofthe helical compression springs in each case passthroughthe disc planes, andthe annulardiscs forming the one abutment are frictionally connected in the region of their inner periphery by means of coupling lami nae to th e one device offlywheel elementandtheannulardiscforming the other abutment are frictionally connected in the region of their outer periphery by means of coupling laminae to the other device or flywheel element.

6. Adevice accordingto any one of Claims 1 to5, wherein the annular discs forming the one abutment have projections on their inner periphery, which projections interact in the manner of stops, with clearance in the peripheral direction, with counter-projections on the one device or flywheel elementora hub part ofthe same, orthe annular discs forming the other abutment have on their outer periphery corresponding projections which interact in the manner of stops, with clearance in the peripheral direction,with counter-projections which are arranged on the other device or flywheel element ora peripheral rim thereof.

7. A device according to any one of Claims 1 to 6, wherein the device orflywheel elements are directly coupled by means of a clutch affected by clearance.

8. A device for reducing vibrations excited in a motor-driven drive line, substantially as hereinbefore described and with reference to any one of Figures 1 to 6 or Figures 5 and 7 modified in accordance with Figure 8 or Figure 9 ofthe accompanying drawings.