GB2217432A

GB2217432A - Clutch disc with disengageable idling damper

Info

Publication number: GB2217432A
Application number: GB8908465A
Authority: GB
Inventors: Harald Raab; Norbert Ament
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1988-04-15
Filing date: 1989-04-14
Publication date: 1989-10-25
Anticipated expiration: 2009-04-14
Also published as: GB2217432B; DE3812573A1; ES2013434A6; FR2630173A1; GB8908465D0; DE3812573C2

Description

a -%f 22 17432 1 CLUTCH DISC WITH DISENGAGEABLE IDLING DAMPER This

invention relates to a clutch disc for motor vehicle clutches with torsional vibration system, in which a spring system with flat characteristic curve and at least one spring system with steeper characteristic curve are provided and the spring system with the flat characteristic curve is blockable or by-passable in dependence upon rotation rate through spring-loaded centrifugal weights.

A clutch disc of the above-stated construcItion type is known for example from DE-OS 3,13.1,045.

Now the invention is based upon the probler,., cf producing, compared with the prior art, the most compact. possible embodiment which is operationally reliable and easy to handle.

According to the invention there is provided a clutch disc assembly for motor vehicle clutches with torsional vibration system, in which a spring system with flat characteristic curve and at least one spring system with steeper characteristic curve are provided and the spring system with the flat characteristic curve is blockable or bypassable in dependence upon rotation rate by means of springloaded centrifugal weights, characterised in that a toothing determining the range of effect of the spring system with the flat characteristic curve is provided, consisting of an external toothing and an internal toothing, which possesses corresponding play in the circumferential direction, while 2 between at least one tooth of the external tooth-,na and a gap of the internal toothing a centrifugal weight is radially -ion rate is displaceable arranged which at lower rotat arranged radially inwards in a rest position and at higher rotation rate moves radially outwards into an active position and there completely fills out the space between tooth and gap.

By arrangement of the centrifugal weights within the tOOthing elements between idling and load systems a very space-saving construction is possible. Moreover the already existing components of the toothing are also used for thz-locking.

In the internal toothing an aperture ma-Y be provided the height of which corresponds to the height of the centrifugal weight and the circumferential extent of which is equal to or less than the circumferential extent of the centrifugal weight. Thus it is ensured that the centrifugal weight is seated circumferentially in the immediate vicinity of the radially 3 outwardly pointing tooth of the external toothing and thus, on charging with higher rotation rate, it is guaranteed that the centrifugal weight can certainly move radially outwards. Furthermore the aperture for the centrifugal weight is arranged on the side of the toothing parts which is loaded in overrun operation. Thus it is guaranteed that in acceleration of the vehicle - starting from a very low rotation rate - the space necessary for the centrifugal weight for radially outward movement is free.

It is proposed to provide several centrifugal weights distributed on the circumference. Furthermore a design is advantageous in which a hub with radially outwardly pointing hub disc is provided, which is provided with the external toothing and in which a hub disc with internal toothing engages, the hub disc constituting the output part of the spring system with the steeper characteristic curve. In such a design the centrifugal weights are formed as substantially cylindrical rollers the axes of which extend parallel to the axis of rotation of the clutch disc; the rollers are axially made longer than the width of the clutch disc and each comprise a guide groove in each of the two end regions, in which in each case there engages, with appropriate initial stress, a worm spring closed upon itself, which loads all rollers. By this design firstly it is made possible to make the centrifugal weights relatively heavy, and also by the two worm springs it is ensured that the individual centrifugal weights can move out 4 simultaneously and also that tilting of them is suppressed. Here in their rest position the rollers lie on the root circle of the external toothing by the initial stress force of the worm springs and thus it is guaranteed that in idling operation their position is not changed in relation to the hub and thus at all times the possibility of radially outward movement exists. Each roller is here provided in its two end regions with a disc of larger diameter which carries the surrounding guide groove for the worm spring. In this way axial fixing of the rollers is provided by these discs. Furthermore it is provided that the hub disc for the idling system is arranged on the hub axially beside the centrifugal weights. Thus a compact style of construction, especially in the radial direction, is possible.

By the formation of the centrifugal weights or parts of them from a material with high density, for example from tungsten, a high certainty of action is achieved even at low rotation rates.

The invention will next be explained in greater detail by reference to an example of embodiment. Individually FIGURE 1 shows the longitudinal section through the upper half of a complete clutch disc; FIGURES 2 to 5 each show a partial section A A according to Figure 1 through the toothing zone, in various positions.

The clutch disc I according to Figure I is arranged fast in rotation but axially displaceably on a gear shaft (not shown). It is made symmetrical in rotation in relation el to the rotation axis 2. It consists of a hub 22 having a radially protruding hub disc 23 in which a hub disc 33 engages from radially outside with play in the circumferential direction by way of a corresponding toothing. The hub disc 33 is part of the load system 3, consisting of the two cover plates 7 and 8, several springs 5 distributed on the circumference and the hub disc 33. One of the two cover plates carries the lining carriers 9 with the two friction linings 10. The two cover plates 7 and 8 are connected fast in rotation with one another and held spaced by distance rivets 11. The two cover plates 7 and 8 are mounted on the hub 22, and in the present case the cover plate 7 is guided exactly by means of a guide ring 15 while the cover plate 8 has a slight play. The springs 5 are arranged in corresponding windows both in the hub disc 33 and in the cover plates 7 and 8, at least one spring being inserted in both kinds of window without play in the circumferential direction.

Radially within the springs and in the axial region between the two cover plates 7 and 8 the idling system 4 is further arranged. It consists of a hub disc 19 which is arranged fast on the hub 22. On both sides of the hub disc 19 cover plates 17 and 18 are arranged which can for example consist of a composite component and are connected fast in rotation with the hub disc 33 and also axially supported on it, in a manner not further designated. Springs 6 are arranged in appropriate windows in the hub disc 19 and in the cover plates 17 and 18. Here again at least one of 6 these springs is inserted in the circumferential direction without play in the corresponding windows In the present case friction devices also belong to the load system 3 and to the idling system 4. These devices consist of a presser ring 14 which is loaded away from the hub disc 33 by a friction spring 12 and clamps in a friction ring 13 between itself and the cover plate 7. On the opposite side a friction ring 20 is clamped in between the outer cover plate 18 of the idling system 4 and the cover plate 8. It is likewise loaded by the friction spring 12 through the distance rivets 11. Furthermore a friction spring 16 is arranged between guide ring 15 and a corresponding edge of the hub 22, the spring force of which spring 16 acts through the distance rivets 11 upon an angle ring 21 which is supported on the hub 22 and the hub disc 19.

As may also be seen in connection with Figures 2 to 5, the hub disc 33 of the load system 3 engages through a toothing in the hub disc 23 of the hub 22 with play in the circumferential direction. In this case several circumferentially distributed teeth 29 are provided on the hub disc 23 and engage in gaps 30 of the hub disc 33. The gaps 30 have such an extent in the circumferential direction that the teeth 29 do not come to abut on the circumferential edges in idling operation. Furthermore on at least some of the gaps 30 a recess 32 is provided serving for the reception of a centrifugal weight 24 in each case, the body of which extends in the form of a roller 25 parallel to the c 7 rotation axis 2 and is held by springs in abutment on the root circle 31 of the hub disc 23 of the hub 22 below a pre determined rotation rate lying above the idling rotation rate. As may be seen especially from Figure 1, each centrifugal weight is connected in its axial end zones outside the width of the hub disc 23 with a disc 26 each, each disc 26 having a guide groove 28 into which a closed worm spring 27 is hooked. Thus all centrifugal weights 24 arranged in distribution on the circumference are held by two worm springs 27 in the rest position according to Figure 2. In idling operation now starting from the rest position according to Figure 2 the hub 22 is deflected in both directions of rotation in relation to the hub disc 33 against the force of the springs 6 and against the force of the friction device, consisting of the parts 15, 16, 19 and 21. However in this movement no parts of any kind of the toothing come to abut on one another. If now during the operation of starting moving the torque in the traction direction is increased, then a movement occurs according to Figure 3. The edge of the tooth 39 facing oppositely to the recess 32 places itself against the corresponding edge of the gap 30. Due to this abutment now the load system 3 comes into action. At the same time the rollers 25 travel out of the recess 32 and rise radially outwards, as represented in Figure 4, against the initial stress force of the worm springs 27. In this position a play-free fixing is effected by the rollers 25 between the teeth 29 and the gaps 30, that is between the hub disc 33 and the hub 22. Thus 8 the idling system 4 is blocked and the load system 3 takes over the further torque transmission and torsion damping. In this condition, on a change of load from traction to overrun or vice versa. the occurrence of load-change noises, which without blocking by the rollers 25 would result in each case in rapid travel through the range of effect of the idling system, is prevented. On a drop in rotation rate below the pre-determined rotation rate and without torque loading upon the drive line, the rollers 25 are drawn radially inwards by the worm springs 27 and can assume their rest position, by resting on the root circle 31. It must be determined here that according to Figure 5 in the case of deflection of the parts 33 and 22 on overrun loading the teeth 29 can come directly into abutment through the rollers 25 on the recess 32. Thus it is made sure that the rollers 25 rest on the root circle 31 always directly on the tooth 29 too.

By arrangement of the two discs 26 with the guide grooves 28, with the two worm springs a symmetrical loading of the centrifugal weights 24 results, so that these can carry out a controlled outward movement. The discs 26 made larger in diameter further provide a satisfactory guidance of the centrifugal weights 24 in relation to the hub 22 with the teeth 29 for the one part and the hub disc 33 with the gaps 30 for the other. Moreover the fitting of the worm springs with the centrifugal weights 24 is considerably more simple to execute than in accordance with the prior art.

The centrifugal weights 24 can be produced completely t 9 from a material with high density, to increase the security of operation. Tungsten for example is suitable as such a material. It is however also possible to produce the only partially from such a material of high density. Thus by way of example it is conceivable to produce the roller 25 alone from tungsten, or to drill through the roller 25 and insert the core of an appropriate material.

centrifugal weights

Claims

CLAIMS:

1. Clutch disc assembly for motor vehicle clutches with torsional vibration system, in which a spring system with flat characteristic curve and at least one spring system with steeper characteristic curve are provided and the spring system with the flat characteristic curve is blockable or by-passable in dependence upon rotation rate by means of spring-loaded centrifugal weights, characterised in that a toothing (29, 30) determining the range of effect of the spring system with the flat characteristic curve (4) is provided, consisting of an external toothing (29) and an internal toothing (30), which possesses corresponding play in the circumferential direction, while between at least one tooth (29) of the external toothing and a gap (30) of the internal toothing a centrifugal weight (24) is radially displaceably arranged which at lower rotation rate is arranged radially inwards in a rest position and at higher rotation rate moves radially outwards into an active position and there completely fills out the space between tooth (29) and gap (30).

2. Clutch disc assembly according to Claim 1, characterised in that the gap (30) of the internal toothing has in the region of the rest position of the centrifugal weight (24) a recess (32) the height of which corresponds to the height of the centrifugal weights (24) and the circumferential extent of which is less than or equal to the circumferential extent of the centrifugal weight (24).

3. Clutch disc assembly according to Claims 1 and 2, i i W 1 i i i i 1 W.

11 characterised in that the recess (32) for the centrifugal weight (24) is arranged on the side of the toothing parts loaded in overrun operation.

4. Clutch disc assembly according to Claims 1, 2 or 3, characterised in that several circumferentially distributed centrifugal weights (24) are provided.

5. Clutch disc assembly according to any one of Clai 1 to 4, in which a hub with radially outwardly pointing hub disc is provided which is provided with the external toothing and in which a hub disc with internal toothing engages, the hub disc constituting the output part of the spring system with the steep characteristic curve, characterised in that the centrifugal weights (24) are made as substantially cylindrical rollers (25) the axes of which extend parallel to the axis (2) of rotation of the clutch disc, in that the rollers (25) are made axially longer than the width of the hub disc (23) and comprise a guide groove (28) in each of the two end regions, into each of which grooves there is inserted with appropriate initial stress a closed worm spring (27), which loads all rollers (25).

6. Clutch disc assembly according to any One Of CliRim 1 to 5, characterised in that the rollers (25) in the rest position rest on the root circle (31) of the external toothing.

7. Clutch disc assembly according to any one of Claims 1 to 6, characterised in that each rolle (25) carries in its end regions a disc (26) of larger diameter with a surrounding guide groove (28) for the worm springs (27).

8. Clutch disc assembly according to any one of Claims 1 to 7, 12 z characterised in that the hub disc (19) for the idling system (4) is arranged on the hub axially beside the centrifugal weights (24).

9. Clutch disc assembly according to any one of Claims 1 to 8, characterised in that the centrifugal weights (24) are produced wholly or partially from material with high density (for example) tungsten.

10. Clutch disc assembly substantially as described with reference to the accompanying drawings.

1 Published 1989 at The Patent Office. State House, 60 7 1 High Holborn. London WCIR 4TP Further copies maybe obtained from The Patent Office. Sales Branch, St Mary Cray. Orpington, Kent BR5 3RD. Printed by Multaplex techniques ltd, St M&T7 Cray, Kent, Con. 1/87