GB2379725A

GB2379725A - Torsional vibration damper with pre-damper

Info

Publication number: GB2379725A
Application number: GB0226961A
Authority: GB
Inventors: Joachim Hoffmann; Steffen Lehmann; Andreas Posch
Original assignee: LuK Lamellen und Kupplungsbau Beteiligungs KG; LuK Lamellen und Kupplungsbau GmbH
Current assignee: Schaeffler Buehl Verwaltungs GmbH; LuK Lamellen und Kupplungsbau GmbH
Priority date: 1998-05-07
Filing date: 1999-05-04
Publication date: 2003-03-19
Anticipated expiration: 2019-05-04
Also published as: GB0226961D0; GB2379725B

Abstract

The torsional vibration damper comprises damper input cover plates 405, 407 driving damper output hub 411 having external teeth via load springs and hub disc 408 having internal teeth and with predamper 402 operating within play between the hub and disc teeth. The predamper has input parts connected to the hub disc and an output part 419 coupled to the hub, the predamper parts compressing energy absorbers therebetween and are located on one axial side of the hub disc. Basic predamper friction damping is provided by engagement of cover plate 407 on contact surface 431a of mounting cone 431 under the preload of diapragm spring 388 and delayed second stage friction damping is provided by relative rotation of the hub disc with friction control disc 429 located on the other side of the hub disc.

Description

TORSION VIBRATION DAMPER The invention relates to a torsion vibration damper, more particularly for motor vehicle clutch discs, with at least one preliminary damper acting in a predetermined angular area and having energy accumulators of lower stiffness, and at least one main damper acting in a predetermined angular area and having energy accumulators of greater stiffness, wherein the energy accumulators are active between the respective input and output parts of the preliminary and main dampers, and the output part of the torsion vibration damper is a hub provided with inner profiled sections to fit onto a gearbox shaft, as well as a flange forming the output part of the main damper is provided with inner profiled sections so that the inner profiled sections engage with the outer profiled sections of the hub and through this profiling the flange of the main damper is able to execute restricted relative rotation relative to the hub, as well as having at least one disc part which forms the input part of the main damper and holds the friction linings, and with at least one friction device.

Torsion vibration dampers with preliminary and main dampers having associated friction devices are known for example from DE 40 26 765 which each have a separate friction device for the main and for the preliminary damper, wherein the preliminary damper has a two-stage friction build-up and two-stage mounted energy accumulators for adapting to the different conditions. The drawback with this type of torsion vibration damper is

the inability to dampen by simple means the torsion vibrations of the pressure plate at high speeds, such as occur for example during engagement and disengagement processes, so that the turning path of the preliminary damper is exceeded and the preliminary damper strikes against its restricting stop and thereby causes clutch noises which cannot be tolerated. Furthermore a construction of this kind is relatively complicated and the assembly becomes correspondingly expensive through the numerous structural elements used, which is all the more apparent if additional measures have to be used to

counteract the clutch knocking previously described- 11 Z, z According to the invention, there is provided a torsion vibration damper having at least one pre-damper acting over an angular region and having energy accumulators of lower stiffness, and at least one main damper acting over a further angular region and having energy accumulators of greater stiffness, wherein the energy accumulators are compressed between the respective input and output parts of the pre-and main dampers, wherein the output part of the torsion vibration damper is a hub provided with inner profiled sections to fit onto a gearbox shaft, which hub receives a flange with inner profiled sections forming the output part of the main damper, with the inner profiled sections engaging with play with the outer profiled sections of the hub, further more an end disc is arranged on both sides of the flange, which are rotationally fast with one another and form the input part of the main damper, wherein an input part and an output part rotationally connected with the hub of the pre-damper are

arranged axially between one of the end discs and the flange of the main damper and a friction control disc is provided axially between the other end disc and the other side of the flange, which is engaged, with play, with the output part provided on the other side of the flange, and within the working range of the pre-damper a second friction stage is connected, which is active only after a relative rotation between input and output parts of the pre-damper from a starting position.

The friction control disc preferably has a contact surface which is in direct frictional engagement with the flange, and can be tensioned by a diaphragm spring against the flange. The diaphragm spring can have a rotationally fast connection with the friction control disc and may have radially outward projecting extensions which cooperate with recesses of the friction control disc to form a rotationally fast connection between these parts.

The diaphragm spring can be supported radially inwardly on a friction ring, and axially tensioned through being supported on the one hand radially outwardly on the friction control disc and on the other hand radially inwardly on a friction ring. The friction ring is preferably supported directly on the adjacent end disc.

In a preferred embodiment, centring is produced between one of the end discs and the hub by means of conical surfaces, and one of the conical surfaces can be formed by a friction ring.

Both the pre-damper and the main damper can have a twostage characteristic.

The first friction stage comprises a diaphragm spring which is axially supported at one side on one of the end discs and biases the hub axially in the direction of the other end disc. A friction ring can be provided between the diaphragm spring and the hub, and the diaphragm spring can be arranged at the side of the main damper flange facing the friction control disc of the pre-damper.

The riven--or, W4-1 1 i-zxn-----The invention will now be explained in further detail with reference to the embodiments shown in the accompanying Figures 1 to 9 in which: Figure 1 shows the torsion vibration damper in longitudinal section; Figure la shows a partial view of the torsion vibration damper; Figure 2 shows a longitudinal sectional view of a part of Figure 1 relating to the preliminary damper; Figure 3 shows a longitudinal sectional view of a part of another embodiment relating to the preliminary damper; Figure 4 is a view of the input part of the preliminary damper with fitted spring; Figure 5 shows a characteristic line of an embodiment; Figure 6a shows a characteristic line of the preliminary damper whilst omitting the friction jump;

Figure 6b shows the path of the friction moment for rotation over the entire active area of the preliminary damper with friction jump; and Figures 7 to 9 show in detail further embodiments of torsion vibration dampers.

The torsion vibration damper 1 shown in the drawings has a preliminary damper 2 and a main damper 3. The input part of the torsion vibration damper 1 which represents the input part of the main damper 3 is formed by a first disc part 5 (not shown complete) supporting friction linings 4 as well as by a second disc part 7 connected rotationally secured to the first part by spacer bolts 6. The output part of the main damper 3 is formed by a flange 8 which has an internal profiled section, preferably internal teeth 9, which engage in an external profiled section, preferably external teeth 10, of a hub 11. Between the external teeth 10 of the hub 11 and the internal teeth 9 of the flange there is a tooth flank play in the circumferential direction which corresponds to the active area of the preliminary damper 2. The hub 11 furthermore has internal teeth 12 for fitting rotationally secured but axially displaceable on a gearbox input shaft.

The main damper 3 has a first set of coil compression springs 13a which can comprise a pair of coil compression springs boxed in each other, for the first main damper stage, which are provided in window-shaped recesses 14a, 15a of the first and second disc part 5,7 on one side as well as in window-shaped cut-out sections 16a of the flange 8. The action of the coil compression springs 13a

is activated through the relative rotation of the recesses 14a, 15a opposite the recesses 16a, after using up the free angle, in which the preliminary damper is active, between the hub 11 and flange 8. A second set of coil compression springs 13b (Figure la) of higher stiffness, which can also consist of coil compression springs boxed in each other, but off-set on a circumference of the same diameter by an angle of preferably 900 relative to the coil springs of the first stage, for the second main damper stage is set in the recesses 14b, 15b (Figure la) of the disc parts 5,7 and in the window-shaped recesses lob (Figure la) of the flange 8 wherein the recesses 16b have a larger cut-out section than the length of the coil compression springs 13b whereby during relative rotation of the disc parts 5,7 opposite the flange 8 the action of this coil spring set 13b is only used with greater turning angles and thus a second damper stage of the main damper is formed. Between the flange 8 and the disc part 5 is a friction control part 23 which has recesses 23a (Figure la) for housing the coil spring set 13b (Figure la) and on these recesses 23a axially aligned tabs 23b (Figure la) which engage in the flange 8 and during rotation of the flange 8 about a turning angle which activates the second main damper stage, entrain the friction control part 23 whereby a friction engagement which only acts in the second main damper stage is produced on a friction disc 34 attached between the friction control part 23 and the flange 8. Furthermore the friction control part 23 has axially extending tabs 24 for holding a plate spring 25 which is supported on a further friction ring 28 fixed on the disc part 7 and thus defines the friction engagement

on the friction discs 28 and 26. The rotation of the main damper is restricted by the spacer bolts 6, which connect the two disc parts 5 and 7 together, stopping against the end contours of the cut-out sections 17 of the flange 8 into which they project axially.

The preliminary damper 2 is mounted axially between the flange 8 and the disc part 7. The input part 18 made from plastics preferably by injection moulding is connected rotationally secured to the flange 8 through pins 26 projecting axially into the corners of the recesses 16 of the flange 8. The output part 19 of the preliminary damper 2 made from plastics preferably by means of injection moulding is connected rotationally secured through internal teeth 19a to the external teeth 10 of the hub 11 whereby as a result of the tooth flank play of the internal teeth 9 of the flange 8 and the external teeth 10 of the hub 11 relative rotation is possible between the output part 19 and input part 18 level with the active area of the preliminary damper 2 against the action of the coil compression springs 27 housed in the window-shaped recesses 21,22 in the output part 19 and the input part 18. The recesses 22 of the output part 19 provided for controlling the coil compression springs 27 are divided alternately into two groups on a circumference of constant diameter of the preliminary damper 2 whereby the recesses of the one group arranged on the same circumference are formed longer in the circumferential direction compared to the other group whereby the coil compression springs 27 housed in this group are only controlled in the event of greater relative rotations to thereby form a second

preliminary damper stage. It is advantageous if the coil compression springs 27 belonging to this group have at the same time a higher stiffness.

The friction device of the torsion vibration damper 1 is made up as follows: the basic friction of the main damper 3 takes place through friction engagement of the friction control disc 23 and the disc part 5 on the friction disc 36 which is connected rotationally secured to same by means of hollow pins 36a, wherein the friction engagement takes place over the entire active area of the main damper 3 and the spring 29 which is supported on the friction ring 28 and on the input part 18 of the preliminary damper 2 which is supported in turn on the flange 8 defines the friction moment. The friction moment of the friction disc 34 already mentioned above and acting in the second main damper stage, between the friction control part 23 and the disc part 5, is likewise fixed by the plate spring 30 which is supported on the friction control part 23. This is joined by a friction moment arising at the friction disc 28 and acting in the entire active area of the main damper 3 and which is defined by the plate spring 29 which is supported on the input part 18, formed as a friction ring, of the preliminary damper 19. After using up the free angle which the spring 29 forms during engagement of its internal teeth 39 with the external teeth 10 of the hub 11, the friction also becomes active in the preliminary damper 2 which leads to a delayed friction jump in the preliminary damper 2. The basic friction of the preliminary damper arises at the friction disc 32 which adjoins the inner circumference of the friction disc

36 and is pressed against the hub 11 by means of a plate spring 33 supported on the disc part 5 and provided with tooth-like outer profile, whereby a part of the radially longer formed teeth engages on one side in recesses 37 of the disc part 5 and thereby produces the rotational lock of the spring and on the other side the remaining part of the shorter teeth engages in recesses 38 of the friction disc 36, wherein the hub 11 is supported in turn on the disc part 7 by means of a cone 31.

The cone 31 which is provided with axial recesses 31a for keyed engagement with the external teeth 10 of the hub 11 serves to centre the disc part 7 on the disc part 5 and causes the fixing of the friction force on the friction discs 34 and 36.

Figure la shows the torsion vibration damper 1 according to the invention in partial view from which for clarity the preliminary damper has been omitted and the parts arranged underneath the disc part 7 are shown by dotted lines. The parts described above are in detail: the first disc part 5 with the friction linings 4 which have grooves 4a is connected rotationally secured by the retaining bolts 6 to the second disc part 7, in-between-building up from below-are the friction control part 23 with its two groups of tabs 23b and 24 as well as the recesses 23a for the second spring set with the coil compression springs 13b which are also fitted into the recesses 14b, 15b of the two disc parts 5,7. The first spring set with the coil compression springs 13a is housed in the recesses 14a, 15a of the two disc parts 5,7. The flange 8

undertakes the control of the spring sets 13a, 13b by its recesses 16a, 16b for the two coil compression spring sets 13a, 13b in the turning angle of the main damper 3 defined by the recesses 17 and retaining bolts 6, wherein the recesses 16b have a larger cut-out section than the length of the coil compression springs 13b so that the entrainment of the springs 13b thereby forming a second main damper stage only takes place in the event of a larger turning angle.

A more detailed explanation of the preliminary damper 2 with the component parts enclosing same is shown in the section from Figure 1 provided in Figure 2. The spring 29 according to the invention is tensioned between the friction ring 28 and the input part 18 of the preliminary damper 2. The inner circumference of the spring 29 is designed as an inner profiled section, preferably as internal teeth 39, which engages in the external profiled section, preferably external teeth 10 of the hub 11 and has a circumferentially arranged tooth flank play which allows relative rotation between the hub 11 and spring 29. The tooth flank play is selected so that the turning angle is smaller than the active area of the preliminary damper 2 so that in the case of large turning angles of the preliminary damper the friction arising through the friction faces 40a (Figure 4) between the spring 29 and input part 18 of the preliminary damper on one side and between the spring 29 and friction ring 28 on the other side, after using up the free angle set between the teeth 10, 39, becomes active on the preliminary damper and produces a friction jump wherein prior to using up the

free angle the spring co-rotates on the input part 18 without producing friction moments.

On the outer circumference the spring 29 has evenly distributed tongues 41 with approximately semi-circular shaped recesses 41a (Figure 4) into which axially protruding pins 42 of the input part 18 project with a play which does not impede the rotation of the spring 29 in the free angle provided but allows assistance during assembly. The input part 18 is formed at the friction face 40a (Figure 4) with the spring 29 as a rounded end 40 so that the spring 29 adjoins with the smallest possible contact bearing angle and thus the friction face 40a (Figure 4) is optimised.

The friction ring 28 forms with the spring 29 a designated friction surface 43 of a raised ring 46 whereby the ring surface drops in the direction of the internal diameter of the ring in order to produce a small contact bearing angle . On the inner circumference of the friction ring 28 which is fitted rotationally secured by axially formed hollow pins 45 in recesses 44 of the disc part 7, a plate spring 30 having outwardly extending tabs 25a (Figure 1) attached on the circumference and supported by these tabs 25a against the tabs 24 of the friction control part 23 (Figure 1) adjoins the ring face 28a and causes a friction moment acting on the main damper 3.

A further design model is shown in the form of a longitudinal section in Figure 3. A torsion vibration damper 101 according to the invention and similar to the

torsion vibration damper 1 has a hub 111 with axially shorter external teeth 110 in which the cone 131 as a second hub part engages with positive locking by means of axial teeth. Furthermore the cone 131 supports external teeth 131a, which preferably differ from the external teeth 110 of the hub 111, into which the spring 129 engages by means of internal teeth 139 producing the tooth flank play required for the delayed friction, whereby it is not necessary to adapt the spring 129 to the hub 111 and in the case of different requirements regarding the delayed friction system only the cone 139 need be changed in respect of the free angle which is to be varied.

A further design possibility relates to the friction ring 128 whose raised ring 146 has a flat ring face 143 wherein the friction face between the ring 146 and spring 129 is optimised in that on the spring 129 in the area of the contact surface with the ring 146 the circumferential bend 129a is adapted to the path of the friction face 143.

Figure 4 shows the hub 11 having the internal teeth 12 which engage in the external teeth of a gearbox input shaft (not shown), and the external teeth 10 which engage

with tooth flank play lOa in the internal teeth of the spring 29 whereby through a tooth flank play lOa in the circumferential direction of preferably 2. 5 the friction jump is controlled by means of the friction moment arising on the friction faces 40a between the spring 29 and the input part 18 of the preliminary damper 2 on one side and between the spring 29 and the friction ring 28,128 (Figures 1, 2 or 3) on the other side,

wherein the size of the friction moment is fixed by the axially acting spring rate of the spring 29.

The spring 29 has on its axial circumference radially extending tongues 41 which hold through their approximately semi-circular shaped recesses 41a the pins 42 which are formed with an axially aligned centre bore 42a wherein the play required for smooth setting the friction jump remains between the tongues 41 and pins 42.

The pins 42 serve as stops against the direction of rotation.

The tongues 41 are widened out at their outer side so that additional friction surface is obtained which is optimised through a rounded end formation 40 of the input part 18 of the preliminary damper 2 relative to the contact bearing angle p of the spring 29 with the input part 18.

Fixing the preliminary damper 2, which is shown here without the output part 10 and the coil springs 27 (Figure 1), on the flange 8 is undertaken by means of pins 26 extending axially at the corners 26a at the side remote from view and which fit into the window shaped recesses 16a, 16b of the flange 8 (Figure 1). The edges 26c of the recesses 26b of the input part 18 of the preliminary damper 2 extending down in the axial direction thereby form a positive locking connection with the window shaped recesses 16a, 16b of the flange.

Figure 5 shows the theoretical path of the turning moment in dependence on the turning angle. The path of the

turning moment in the event of small turning angles in the direction of the pull side, thus in the direction in which the drive assembly turns the torsion vibration damper whilst the gearbox input shaft is still stationary is in this embodiment orientated up to about 90 from the damping properties of the two-stage preliminary damper 2 (Figure 6a). The first stage of the main damper 3 is set after using up the free angle between the external teeth 10 of the hub 11 and the internal teeth 9 of the flange 8.

The second main damper stage is set after using up the clearances of the recesses 16b of the flange with a turning angle of 160. The increase in the turning moment is more than double the turning moment of the first main damper stage since the coil compression springs 13b of the second main damper stage have a higher stiffness compared with the coil compression springs 13a of the first stage.

With a turning angle of about 20.5 0 in this embodiment the recess 17 of the flange 8 strikes against the retaining bolts 6 which connect the disc parts 5, 7 together so that the action of the main damper stage is terminated.

In the push side direction the free angle of the preliminary damper 2 is restricted to a turning angle of 2. 50 so that the first main damper stage only starts from this turning angle. Also the start of the action and the stop of the second main damper stage are restricted to turning angles of 12. 50 and 140 respectively.

Figure 6a shows an enlarged area of Figure 5 for a better illustration of the turning moment of the preliminary

damper 2 over the turning angle. In the pull direction (right section of the drawing) the first preliminary damper stage cl operates at turning angles up to 60. In the case of larger turning angles the clearance of the recesses 22 of the output part 19 of the preliminary damper 2 is used up and the second preliminary damper stage c2 is activated up to an angle of 90 at which the free angle between the external teeth 10 of the hub 11 and the internal teeth 9 of the flange 8 is used up and the main damper device is used. The method of operation of the preliminary damper is in this embodiment serial, that is the spring tension of the preliminary damper 2 remains during the action of the main damper 3. The preliminary damper 2 has during the push operation a restricted turning ability, namely a turning angle of 2. 50 wherein only the first preliminary damper stage is activated.

Figure 6b shows the path of the turning moment M of an embodiment of the preliminary damper 2 according to the invention in dependence on the turning angle a taking into account the hysteresis H1 conditioned by the friction device.

The solid lines marked by arrows thereby show the path of the turning moment in the direction of the arrows when the preliminary damper 2 has turned and with a reversal of the turning angle, the dashed lines show the path of the curve of the turning moment without friction jump and the chain-dotted line shows the mean value of the turning moment corrected by the hysteresis without taking into account the friction jump.

Starting with a turning angle a at which during push operation the preliminary damper is standing against the stop and only the first preliminary damper stage is active, the turning moment M in relation to the pull side decreases to a turning angle of 0 , the neutral phase of the first preliminary damper stage. The turning moment M then increases successively in dependence on the spring rate and the basic friction of the first preliminary damper stage up to the free angle FW between the internal teeth 39 of the spring 29 and the external teeth 10 of the hub 11. The spring 29 is then entrained by the hub 11 and produces through the resulting relative rotation a friction moment at the contact faces with the friction ring 28 and with the input part 18 of the preliminary damper 2 from which the illustrated friction jump Rl arises with the turning angle FW. The additional friction moment is superimposed on the friction moment of the first preliminary damper stage until the second preliminary damper stage by way of example c2 (Figure 6a) is activated with an additional friction moment in the case of a turning angle of 60. From the pitch of this curved section it is clear that the coil compression springs of the first preliminary damper stage have smaller stiffness than the coil compression springs of the second preliminary damper stage. At the end A of the active area of the preliminary damper 2 in the pull direction the turning angle is changed over whereby the hysteresis HI acts in the reverse direction and the friction moment of the friction jump Rl ceases since now the relative rotation of the spring 29 opposite the hub 11 is provided

again through the changed direction of rotation by means of the free angle relative to the hub 11. With a reverse turning angle of 30 in relation to the embodiment in Figure 6a the second preliminary damper stage becomes inactive again and the friction moment M drops to the value of the first damper stage reduced by the hysteresis HI in the event of a full deflection. A further decrease in the turning angle a causes the free angle to be used up between the spring 29 and the hub 11 in the reverse direction and the friction jump Rl is set analogous with the other positive turning direction wherein an angular stagger is observed in the case of the two turning directions which results from the non-uniformity of the active areas in the pull and push type operation of the preliminary damper 2 (Figure 6a). With a reduction in the turning angle the first preliminary damper stage runs through the neutral phase and a negative turning moment M is built up up to the end B of the push direction.

Figure 7 shows a detail of an embodiment with a torsion vibration damper 201 in which the input parts 205,207 are tensioned relative to one another by means of the diaphragm spring 233, with axial interposition of the cone 231 which itself is axially supported on a radially extending shoulder 211a of the hub 211 so that a centering of the disc part 207 on the cone 231 is effected by the axial spring constant of the diaphragm spring 233. For optimisation of the centering of the side disc 207 on the cone 231 the cone angle a of the cone 231 and the disc part 207 in the region 207a of the contact surface of the

cone 231 is set between 0 < a < 450, preferably 250 < a < 350. On a relative rotation between the hub 211 and the disc parts 205, 207 a friction torque arises at the cone 231 which is determined in dependence on the cone angle alpha, the friction surfaces in contact with one another, the spring constant of the diaphragm spring 233 and the friction values of the relatively rotating parts. Thus the friction engagement between the region 207a and the cone 231 at the cone surface 231a and/or preferably between the cone 231 and the output of the energy store 219 of the pre-damper at the contact surface 231b can be adjusted so that here between the two parts 231, 219 a friction plate can be provided. The driven side control or biasing of the energy store 227 occurs by means of a control plate 227a engaging from the side of the disc part 205 in the energy store 227, which control plate engages in the toothing 219a of the hub 211.

Figure 8 shows a further construction, similar to the embodiment of Figure 7, of a detail relating to the cone 331 with a cone angle 0 < a < 45 , preferably 250 < a < 350 and a friction contact to the hub toothing 219a under formation of friction surface 331b, which produces a friction torque on a relative rotation of the radially outer disc part 305,307 which are axially connected to one another, against the hub 311. The two disc parts 305, 307 are thus tensioned, against the hub 311, with axial interposition of the cone 331 on the one side and an abutment ring 332 on the other side by means of the axially operating diaphragm spring 333 which supports itself on the disc part 305 and on the abutment ring 332.

Figure 9 shows a modified embodiment of the torsion vibration damper 1 in Figure 1. The torsion vibration damper 401 of Figure 9 illustrated as a part section has in the region of a pre-damper 402 a friction device 428 arranged so that the diaphragm spring 433 itself offers no friction function but only the tension of the friction control disc 429 against the cone 431 on the one hand as well as against the flange 408 on the other hand. In this way, a two stage construction of the friction device 428 is possible.

The first step is to find by an axial tensioning of the two radially outer disc parts 406,407 which are connected with one another, with axial inter position of the cone 431 with the hub 411 by means of the diaphragm spring 488.

By the pretensioning of the disc parts 405,407 there arises a friction engagement on a relative rotation of the hub 411 against the disc parts 405,407 as a first friction stage at the contact surface 431a between the cone 431 and the disc part 407, wherein on appropriate setting up of the friction conditions, the friction engagement in accordance with Figures 7 and 8 also in the contact region 431b between hub 411 and cone 431 can be transferred, in that for example the cone angle a of the contact surface 431c can be steeper wherein at this position the friction torque can be reduced and the centering of the disc part 405,407 on the cone 431 is improved.

The second friction stage occurs on a relative rotation of the flange 408 relative to the friction control disc 429, thus in the working region of the pre-damper 402, wherein the friction torque is formed at the contact surface 429a of the friction control disc 429 to the flange 408 and the friction control disc 429 is hooked into the output part 419 and by means of a rotational play between the parts 429,419 a slipping friction can be produced. In order to avoid the diaphragm spring 433 from moving relative to the cone 431 and/or the friction control disc 429, radially projecting extensions 433a, 433b are provided at the inner and outer circumferences, which with axially raised cams 431d of the cone 431 and recesses 429b of the friction control disc 429 form rotationally fast connections. The diaphragm spring 433 produces in the embodiment an increased tension of the cone 431 with the disc part 407 additionally to the action of the diaphragm spring 408, whereby especially on a misalignment of the drive unit in the gear box an improved tensioning and thus a better centering of the disc part 405 on the cone and a better defined friction engagement is possible.

The invention is not restricted to the embodiments of the description. Numerous amendments and modifications are possible within the scope of the invention as defined by the claims, particularly those variations, elements and combinations and/or materials which are combinations or modifications of individual features or elements or process steps contained in the drawings and described in connection with the general description and embodiments and claims.

Claims

1. Torsion vibration damper having at least one pre- damper acting over an angular region and having energy accumulators of lower stiffness, and at least one main damper acting over a further angular region and having energy accumulators of greater stiffness, wherein the energy accumulators are compressed between the respective input and output parts of the pre-and main dampers, wherein the output part of the torsion vibration damper is a hub provided with inner profiled sections to fit onto a gearbox shaft, which hub receives a flange with inner profiled sections forming the output part of the main damper, with the inner profiled sections engaging with play with the outer profiled sections of the hub, further more an end disc is arranged on both sides of the flange, which are rotationally fast with one another and form the input part of the main damper, wherein an input part and an output part rotationally connected with the hub of the pre-damper are arranged axially between one of the end discs and the flange of the main damper and a friction control disc is provided axially between the other end disc and the other side of the flange, which is engaged, with play, with the output part provided on the other side of the flange, and within the working range of the predamper a second friction stage is connected, which is active only after a relative rotation between input and output parts of the pre-damper from a starting position.

2. Torsion vibration damper as claimed in Claim 1, wherein the friction control disc has a contact surface which is in direct frictional engagement with the flange.

3. Torsion vibration damper as claimed in Claim 1 or Claim 2, wherein the friction control disc is tensioned by a diaphragm spring against the flange.

4. Torsion vibration damper as claimed in Claim 3, wherein the diaphragm spring has a rotationally fast connection with the friction control disc.

5. Torsion vibration damper as claimed in Claim 3 or Claim 4, wherein the diaphragm spring has radially outward projecting extensions which cooperate with recesses of the friction control disc to form a rotationally fast connection between these parts.

6. Torsion vibration damper as claimed in any one of Claims 3 to 5, wherein the diaphragm spring is supported radially inwardly on a friction ring.

7. Torsion vibration damper as claimed in any one of Claims 3 to 6, wherein the diaphragm spring is axially tensioned through being supported on the one hand radially outwardly on the friction control disc and radially inwardly on a friction ring.

8. Torsion vibration damper as claimed in Claim 6 or Claim 7, wherein the friction ring is supported directly on the adjacent end disc.

9. Torsion vibration damper as claimed in any preceding claim, wherein centring is produced between one of the end discs and the hub by means of conical surfaces.

10. Torsion vibration damper as claimed in Claim 9, wherein one of the conical surfaces is formed by a friction ring.

11. Torsion vibration damper as claimed in any preceding claim, wherein both the pre-damper and the main damper have a two-stage characteristic.

12. Torsion vibration damper as claimed in any preceding claim, wherein the first friction stage comprises a diaphragm spring which is axially supported at one side on one of the end discs and biases the hub axially in the direction of the other end disc.

13. Torsion vibration damper as claimed in Claim 12, wherein a friction ring is provided between the diaphragm spring and the hub.

14. Torsion vibration damper as claimed in Claim 11 or Claim 12, wherein the diaphragm spring is arranged at the side of the main damper flange facing the friction control disc of the pre-damper.