GB2303196A

GB2303196A - Clutch disc assembly with torsion dampers

Info

Publication number: GB2303196A
Application number: GB9613878A
Authority: GB
Inventors: Norbert Ament; Georg Kraus
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1995-07-07
Filing date: 1996-07-02
Publication date: 1997-02-12
Anticipated expiration: 2016-07-02
Also published as: FR2736406A1; DE19524749C1; ES2142196A1; BR9602996A; GB9613878D0; FR2736406B1; GB2303196B; ES2142196B1

Description

1 1 DescriDtion "Clutch disc assembly with torsion dami)ers" 2303196 The

invention relates to a clutch disc assembly.

A clutch disc assembly is known from DE 39 22 730 AI in which a main torsion damper is disposed between cover plates and a hub disc, supported with rotational play on a hub which is rotationally-locked with a transmission shaft. Springs of the main torsion damper are accommodated in windows of the cover plates and the hub disc and the damper employs a friction loading device. An idling torsion damper is also arranged wdally between the hub disc and one of the cover plates. The idling torsion damper comprises another secondary hub disc rotationally-locked to the hub, secondary plates arranged on both sides thereof and springs which engage in windows in the secondary hub disc and the secondary plates. A friction ring is arranged axially between one of the cover plates of the main torsion damper and the adjacent secondary plate of the idling torsion damper. The fliction ring is guided outwards in a radial direction through the secondary plate adjacent to the associated cover plate and has axial projections in the outer radial region which engage in recesses of the hub disc. To create specific rotational play between the friction ring and hub disc the recesses are larger in circumference than the projections. The fliction ring is supported on the one hand on the cover plate of the main torsion damper and on the other hand by an axial thrust spring on the adjacent secondary plate of the idling torsion damper.

2 By means of the axial arrangement of the friction ring between a cover plate of the main torsion damper and the adjacent secondary plate of the idling torsion damper, friction loading occurs, if the actual area of influence of the friction ring, namely the range of the idling load torsion damping, has already been left, as in the range of the main torsion damping there is a relative rotation between the cover plates acting as the input of the main torsion damper and the hub disc acting as the output thereof and because of the rotationally-locked connection between the secondary plates of the idling torsion damper with the hub disc and also between the latter and the cover plate. Accordingly the friction ring is continually loaded even in a range of operation in which it is not supposed to be elfective and is therefore subjected to rapid wear, in particular when the friction ring is made of plastic, at least on one of its frictional surfaces. The wear of the friction ring on these frictional surfaces can lead to a change in tension of the wdal thrust force loading it, whereupon the damping behaviour in the actual area of influence of the friction ring, namely with the idling torsion damping operating, could be adversely afFected.

An object of the invention is to provide an improved clutch disc assembly in which the idling torsion damper is subjected to minimal wear.

According to the invention there is provided a clutch disc assembly with torsion vibration damping for motor vehicle clutches; said assembly comprising a hub for fitting onto a transmission shaft for rotation therewith, a hub disc which is arranged on the hub 3 with specific rotational play and forms an output of a main torsion damper, at least one cover plate alongside the hub disc, energy stores of the main torsion damper arranged between the cover plate and the hub disc, an idling torsion damper which is arranged axially between the cover plate and the hub disc, the idling torsion damper being composed of at least one finther secondary plate forming an input for the idling torsion damper, a flu-ther secondary hub disc, an axial energy store and a fliction ring, the further secondary plate being rotationally-locked to the hub and the friction ring engaging by means of an axial projection with the further secondary hub disc with rotational play of a smaller angle than the play between the hub disc and the hub, and the axial energy store being supported on the cover plate to provide an axial force for locating the idling torsion damper between the cover plate and the hub disc of the main torsion damper, characterised in that the axial energy store for the idling torsion damper is part of a loading friction device of the main torsion damper and the ffiction ring is positioned axially between the flu-ther secondary plate and the hub disc and is flictionally engaged under the effect of the axial energy store.

It is convenient for there to be two primary cover plates associated with the main torsion damper and two secondary plates associated with the idling torsion damper. Since the friction ring is disposed axially between the hub disc of the main torsion damper and one of the secondary plates of the idling torsion damper it is located between two components which, because of their rotationally-locked connection, do not move relative to one another. Because of this both in the range of the fliction influence in the 4 idling motion, in which the ffiction ring, participating in the movement of the hub disc of the main torsion damper and the secondary plates of the idling torsion damper, can move relative to the secondary hub disc, and within the range of main torsion damping in which the secondary hub disc, the secondary plate, the friction ring and the hub disc move relative to the cover plates of the main torsion damper, the friction ring remains free of movement relative to the adjacent cover plate or the adjacent hub disc. When the idling torsion vibration damper is operative the secondary plates of the idling torsion damper and the hub disc of the main torsion damper flictionany follow the cover plates of the latter, whilst the friction ring after using up its play relative to the secondary hub disc of the idling torsion damper has already taken up its position and come to a stop. Only in a small range of operation is there a relative movement between the ffiction ring and the adjacent components so that the period during which it is subjected to wear is reduced to a minimum. Therefore even if the fliction ring is made of plastic a change in the behaviour of the idling torsion damper because of the egect of wear is minimi ed.

A fi=her advantage of the disc assembly is that the ftiction ring is frictionally engaged between the components by the axial energy store of the main torsion damper so that it does not require its own energy store. By arranging the friction ring carefidly relative to the components of the main and the idling torsion damper the number of components can be reduced.

The idling torsion damper may have finther secondary plates on both sides of the secondary hub disc. A rotationally-locked drive of the finther plates relative to the hub disc of the main torsion damper can be established by means of axially bent tabs on one of the further plates adjacent to the cover plate of the main torsion damper which, without circumferential play, extends into recesses in the other fin-ther plate and also without circumferential play into recesses in the hub disc.

The friction ring is arranged axially between the hub disc and the other further plate provided with the recesses can also be provided with projections which extend axially through the further plate into recess provided in the hub disc.

It is desirable to provide an axial engagement of the projections of the friction ring so that a radial extension of the latter over the cover plate can be avoided. By designing the openings in the cover plate to have a larger circumference than the recesses of the hub disc the movement of the fliction ring is not restricted.

An embodiment of the invention will be described in more detail in the following description with reference to the accompany drawings wherein

Fig. 1 is a complete axially-longitudinal section of a clutch disc assembly constructed in accordance with the invention; 6 Fig. 2 is an enlarged view of the upper half of the sectional view according to Fig. 1; Fig. 3 is a part-sectional end view of the assembly shown in Figures 1 and 2; Fig. 4 is a view corresponding to Fig. 2, but depicting a dilferent design of the idling torsion damper.

Figures 1 to 3 show an entire clutch disc assembly which has a hub 1 mounted rotationally-locked but axially displaceable on a transmission shaft (not shown) for rotating about an axis of rotation 3. The hub 1 is connected circumferentially with a hub disc 2 by means of a toothed wheel 4 with rotational play 5. Cover plates 6 and 7 are arranged on both sides of the hub disc 2 and the plates 6, 7 are connected to one another in the region of their outer diameter by connecting rivets 35. Torsion springs 9 are arranged in windows of the cover plates 6 and 7 and in windows of the hub disc 2. The springs 9 in cooperation with the cover plates 6 and 7 and the hub disc 2 form a main torsion damper 14. Friction finings 8 are secured to the outer circumference of the cover plate 6. Both cover plates 6 and 7 are guided for rotation by a bearing ring 22 disposed on the inner diameter of the cover plate 6 in radial engagement with the periphery of the hub 1. An idling torsion damper 15 is arranged between the hub disc 2 and the cover plate 6. The damper 15 is composed of two finiher secondary discs or plates 10 and 11, a flinher hub disc 12 and torsion springs 13. The hub disc 12 is fixed for rotation onto 7 the hub 1 and all the associated components are wdally secured thereto. The plate 10 of the idling torsion damper 15 adjacent to the cover plate 6 of the main torsion damper 14 comprises in the region of its outer circumference and radially outside the torsion springs 13 axially angled projections 16, which extend into recesses 17 in the hub disc 2 and thereby form a circumferential rotationally-locked connection. The same projections 16 also secure the plate I I circurnferentially adjacent to the hub disc 2 in that they engage without play in recesses 38 in the plate 11. In an axial direction, the plate 10 rests by means of support edges '56 on the plate I I and both are supported axially by means of a friction ring 27 on the hub disc 2. The axial supporting force is produced by an axial energy store 18 in the form of a disc spring which is positioned axially between the cover plate 7 and an angular ring 19 which is connected rotationally-fast - but axially displaceably - to the cover plate 7 and loads a friction lining 20 which is supported on the hub disc 2. The amdal force of the energy store 18 is controlled by one of the connecting rivets 35 on the cover plate 6 and from there by a fliction lining 21 to the outer cover plate 10 of the idling torsion damper 15. Thus the system is closed in the vial direction whereby the axial energy store 18 together with the angled ring 19 and the friction linings 20, 21 forms a loading friction device 40. The mial guiding of the rotatable components is performed by means of the bearing ring 22 which is inserted and axially securely in the cover plate 6. The latter is loaded by a zigzag spring 24 which is supported on the opposite side of the toothed wheel 4 of the hub I by means of a spacer ring 23. The spring force is transferred via the cover plate 7 and the connecting rivet 3 5 to the cover plate 6. In this way the hub I together with the zigzag spring 24, the bearing 8 ring 22 and the spacer ring 23 forms a base friction device 25 with a low coefficient of friction which is effective over the entire angular rotational range. In the region of influence of the main torsion damper 14 in addition to this frictional force there is an additional force which is produced by the two friction linings 20 and 21 in connection with the axial energy store 18. Furthermore, an entrained idling loading friction device 26 is provided which is formed by the friction ring 27 arranged between the axially innermost plate I I of the idling torsion damper 15 and the hub disc 2 of the main torsion damper 14 and is frictionally held under the effect of the axial energy store 18 between the two said components 2 and 11. The friction ring 27 comprises several projections 28 distributed around its periphery, pointing a-,dally in the direction of the hub disc 12, which engage in recesses 30 of the hub disc 12 with circumferential play. Thus in Fig. 2 for illustration purposes a projection 28 is depicted in a dash-dotted line into the section plane, whilst in the example according to Fig. 3 the projections 28 and 16 are arranged distributed about the periphery. In this way the projections 28, 16 can be made to have the same diameter and thus take up little space in the radial direction.

Briefly the operation of the clutch disc assembly is as follows:

During idle running of the internal combustion engine, the components 6, 7, 9, 2 of the main torsion damper 14 are to be seen as a rigid unit and they move relative to the hub 1 in a circumferential direction only the rotational play 5 of the toothed wheel 4 between the hub disc 2 and the hub 1. In this state of operation the idling torsion damper 15 is loaded with its torsion springs 13. The loading of the torsion springs 13 is 9 performed by means of the two plates 10 and I I connected rotation-fast to the hub disc 2 and the hub disc 12 rotationally-locked to the hub 1. The following components are used to produce friction:

First of all, the basic friction device 25 effective over the entire range of influence of the clutch disc assembly and comprising parts 22, 12, 1, 23 and 24. A first frictional contact is produced between a nose 37 formed on the bearing ring 22 and directed towards the hub disc 12 and a second friction contact is produced between the hub I and the zigzag spring 24 by means of the spacer ring 23. In addition, on exceeding a predetermined angle the fictional force of the idling loading fhction device 26 is effective. More particularly the projections 28 of the friction ring 27 entrained by the rotationally-locked components I I and 12 after using up the rotational play relative to the recesses 30 in the hub disc 12 rest on the restriction of the recesses 30, whereupon the movement of the friction ring 27 is adapted to that of the hub disc 12 and the hub 1, whilst the plates 10 and I I and the hub disc 2 follow unchanged the movement of the cover plates 6 and 7. As a result fliction is created on the one hand between the friction ring 27 and the plate I I adjacent thereto and on the other hand between the friction ring 27 and the hub disc 2. The ftiction remains until the play 5 in the toothed wheel 4 between the hub I and the hub disc 2 is used up. Each time on reversing the direction of rotation there is first an free movement corresponding to the play between the projections 28 and the recesses 30 without producing friction. As soon as the play 5 in the toothed wheel 4 is used up completely the hub disc 2 and the plates 10 and I I and the hub disc 12 of the idling torsion damper 15 are rotationally-locked with the hub 1, so the clutch disc assembly works in the region of the main torsion damping. Because of this the fliction ring 27 is held again free of forces acting in a circumferential direction between the plate 11 and the hub 2 and therefore no longer effective. Friction contact occurs between the cover plate 6 of the main torsion damper 14 and the adjacent plate 10 of the idling torsion damper 15 and on the other hand between the angled ring 19 rotationally-locked with the cover plate 7 and the hub disc 2 on the friction linings 20 and 21.

Finally, it should also be mentioned that with each reversal in the direction of rotation of the rotatable components relative to the hub 1 the idling loading fliction device 26 first runs through the clearance angle before it is effective again. The adjustment of the flictional force can be performed in a simple manner in that friction finings which are used can have different material compositions.

In contrast to the embodiment as described above and illustrated in Figures I to 3 the projections 28 on the friction ring 27 in the embodiment according to fig. 4 are not disposed radially outside the adjacent plate I I but run inside the extension area of this cover plate in the direction of the hub disc 12. In this way the projections 28 penetrate assigned openings 33 in the plate I I extending in a peripheral direction and engage in the recesses 30 of the hub disc 12. The openings 33 in the plate I I are sufficiently large in the circumferential direction not to hinder relative movement between the friction ring 27 and the hub disc 12. Preferably, the openings 33 are therefore larger in circumference than the recesses 30 in the hub disc 12. Otherwise, the design of the torsion vibration 11 damper according to fig. 4 corresponds to the one described above for which reason it is not explained further here.

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Claims

1. A clutch disc assembly with torsion vibration damping for motor vehicle clutches; said assembly comprising a hub for fitting onto a transmission shaft for rotation therewith, a hub disc which is arranged on the hub with specific rotational play and forms an output of a main torsion damper, at least one cover plate alongside the hub disc energy stores of the a main torsion damper arranged between the cover plate and the hub disc, an idling torsion damper which is arranged axially between the cover plate and the hub Clisc, the idling torsion damper being composed of at least one further secondary plate formiAg an input for the idlin k. g torsion damper, a further secondary hub disc, an axia! energy store- and a friction ringa, the further secondary plate being rotationallylocked to t_he hub and the friction ring engaging by means of an axial projection with the further secondary hub disc with rotational play of a smaller angle than the play between the hub jIsc and the hub, and the axial energy store being supported on the cover plate to provide an vial force for locating the idling torsion damper between the cover plate and the hub disc of the main torsion damper, characterised in that the axial energy store (18) for the idling torsion damper is part of a loading fliction device (40) of the main torsion damper (14) and the friction ring (27) is positioned axially between the finther secondary plate (11) and the hub disc (2) forming an output of the main torsion damper (14) and is frictionally engaged under the effiect of the axial energy store (18).

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2. A clutch disc assembly according to claim 1, wherein the idling torsion damper has two further secondary plates (10, 11) on both sides of the secondary hub disc (12), and a rotationally-locked drive of the finther plates relative to the hub disc (2) of the main torsion damper is established by means of axially bent tabs on one of the fimther plates (12) adjacent to the cover plate (7) of the main torsion damper, which without circumferential play extends into recesses (38) in the other further plate (11) and also without circumferential play into recesses (17) in the hub disc (2).

3. A clutch disc assembly according to claim 2, wherein the friction ring (27) is arranged axially between the hub disc (2) and the other further plate (11) and is provided with projections (28', which extend axially through the other further plate (11) into recess (30) provided in the hub disc (12).

4. A clutch disc assembly according to claim 3, wherein the projections (28) extend through openings (33) in the one finther plate (11) which are larger than the recesses (30) in the hub disc (12).

5. A clutch disc assembly substantially as described herein with reference to, and as illustrated in, any one or more of the Figures of the accompany drawings.