GB2251285A

GB2251285A - Clutch disk assembly for a motor vehicle friction clutch

Info

Publication number: GB2251285A
Application number: GB9127019A
Authority: GB
Inventors: Harald Raab; Norbert Ament; Peter Wiggen; Juergen Kleifges
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1990-12-19
Filing date: 1991-12-19
Publication date: 1992-07-01
Anticipated expiration: 2011-12-19
Also published as: FR2670852A1; GB2251285B; DE4040595C2; FR2670852B1; GB9127019D0; DE4040595A1

Abstract

A clutch disk assembly comprises an idling damper system 5, 8, 11-14 and a load damper system 3, 4, 6, 10, 21-23 in which, after the idling damper system has been bridged over, the load damper system is provided with an idling path in the region of the transition from the idling relative rotational angle range of the idling damper system 5, 8, 11-14 into the load relative rotational range, solely the friction device 21-23 of the load damper system being effective in the said idling path. <IMAGE>

Description

2231235 CLUTCH DISK ASSEMBLY FOR A MOTOR VEHICLE FRICTION CLUTCH The

invention relates to a clutch disk assembly for motor vehicle friction clutch having an idling damper system (springing and optionally friction) which acts only in the idling rang e, as well as a load damper system (springing and friction) which acts after the idling range.

A clutch disk assembly of this design is known, for example, from DEPS 1 680 049. With this known clutch disk assembly, the higher frictional force of this system is employed together with the steeper springing characteristic curve of the load damper system. With certain operating states, it is now possible for rotational angle movements to occur which go beyond the idling range and sometimes extend into the load range. This is possible, for example, during the start up of the internal combustion engine, during the stoppage of the internal combustion engine and during rapid clutch engagement. With these running states, in which this point in the characteristic curve is to be passed over very rapidly, the increase in the frictional force as well as optionally a slight initial tension of the springs of the load damper system act as a stage jump, corresponding noises being audible.

An object of the present invention is to eliminate the above described noises using means which are as simple as possible.

According to the invention there is provided a clutch disk assembly for a motor vehicle friction clutch having a torsional vibration damper which comprises an idling damper system dimensioned for idle running as well as a load damper - system dirensioned for'load running, wherein both the idling damper system and the load damper system have input parts and output parts which are rotatable relative to one another round a common axis of rotation, are torsionally elastically connected to one another via separate spring means and at least the load damper system comprises a friction device and wherein the idling damper system is effective solely in an idling relative rotational angle range allocated to idle running and the load damper system is effective in a load relative rotational angle range outside the idling relative rotational angle range, wherein the spring means of the load damper system is allocated an idling rotational path in the region of the transition from the idling relative rotational angle range into the load relative rotational angle range, solely the friction device of the load damper system being effective in this idling rotational path.

By allocating an idling rotational path to the load damper system in which only the load friction is effective, the stage jump can be reduced until it no longer appears in an undesirable manner. Within this idling path, therefore, the spring force does not increase and the jump in the frictional force produced during the transition into the load damper system has to be overcome only at the beginning of the idling path.

With a clutch disk with which the idling damper system is bridged overby stops after the idling rotational path has been covered, it is proposed that all helical springs arranged in the input and output parts of the load damper system are inserted into corresponding apertures which, in one type of part - input or output parts - correspond to the peripheral dimension of the springs and, in the other parts, ok LeosP_ are peripherally greater in designby the proposed 'idling path than the dimension of the springs. This ensures that an idling path in which only the frictional force of the load damper system is effective has to be passed through after the effective range of the idling damper system. Therefore, no increase in spring force is recorded in this idling path and the frictional force acting there is uniform over the rotational angle of the idling path.

In a preferred embodiment, the springs of the load damper system are preferably inserted without clearance or with slight initial tension in the apertures of the input parts, which, for example, can have the form of a covering disk or a lining carrier, whereas the apertures of the output part, for example a hub disk, are peripherally greater in design by the size of the idling path. Exact fixing of the springs in the covering disk or in the lining carrier is therefore achieved and is effective in particular even at relatively high speeds.

If several spring stages are provided in the load damper system, the apertures of the second and the further stage have to be correspondingly greater in design than the size of the idling path.

The invention is described in more detail hereinafter with reference to an embodiment.

Figure 1 is a schematic diagram of the torsional vibration damper of a clutch assembly with_load and idling damper system, Figure 2 is a graph showing the trend of the torque M a function of the rotational angle c& of the torsional vibration damper, and Figure 3 is an axial longitudinal section through an embodiment of the clutch disk assembly.

Figures 1 and 2 should be viewed together. The basic arrangement according to Figure 1 shows a torsional vibration damper with an idling damper system and a load damper system in the rest position. The springs 14 of the idling system are relaxed and a hub disk 6 of the load damper system is orientated centrally with respect to an internal hub 8, the internal hub 8 being non-rotatably arranged on a gearshaft (not shown). Between the hub disk 6 and the internal hub 8 there are arranged clearance teeth 7 which allow relative rotation of the two parts by the angle&,, or O2. The clearance teeth 7 are arranged between the internal hub 8 and an external hub 5, the external hub 5 being designed integrally with the hub disk 6. Several apertures 18 which are distributed round the periphery and co-operate with springs 10 of the load damper system are also arranged in the hub disk 6. A friction lining carrier 3 and a covering disk 4 which are also equipped with apertures 19 and 20 for receiving the springs 10 are arranged on either side of the hub disk 6. The apertures 19 and 20 are provided with a peripheral dimension which is such that the springs 10 are held therein at least without clearance and optionally with slight initial tension. The corresponding apertures 18 in the hub disk 6 are peripherally greater in design by an amount X in one direction and by an amount Y in the other direction than the peripheral dimension of the fitted springs 10. As described hereinafter in conjunction with the description of Figure 3, the frictional force of a load friction device acts between the hub disk 6 and the parts 3 and 4 during relative rotation. The idling damper system can also be provided with a friction device which is however adjusted to a very low level.

During torque loading of the input parts of the load damper system, i.e. during introduction of torque into the friction lining carrier 3 and the covering disk 4 in the pulling direction (-c& direction) or in the pushing direction (+c'-direction) corresponding to the arrows, and when the internal hub 8 is considered to be fixed, the following sequence of movements takes place: during torque loading in the pulling direction, all parts of the load damper system are rotated as a complete unit in a clockwise direction against the force of the springs 14 of the idling damper system owing to the high frictional force of the load friction device acting between them. A torque corresponding to the flat spring characteristic curve in Figure 2 is formed, starting from the neutral position corresponding to zero on the torque axis M and the rotational angle axis c&. The build-up of torque on this flat spring characteristic curve continues until the clearance teeth 7 come to rest on one side after the angle c.1 has been covered. From this moment on, the idling damper system is bridged over and the load damper system comes into use. This means, however, that a pure frictional force initially has to be overcome as the spring 10 of the load damper system is loaded only after the path X has been covered. The rotational angle path X therefore extends parallel to the rotational angle axis without an increase in torque. After this path X has been covered, one or all springs 10 of the load damper system are loaded and the characteristic curve has a substantially steeper trend from here. With the return stroke during the reduction of torque, a reduction and the reversal of the load friction moment takes place first of all and then a backward movement parallel to the run up with the same steep spring characteristic. At the kink between the steep and the flat spring characteristic curve, therefore when the springs 10 are relaxed, the load damper system as a unit will carry out a complete backward movement corresponding to the sum of the angles c(, and c 2 The springs 14 of the idling damper system are therefore relaxed and tensioned again. After this run through and after the clearance teeth 7 have struck the opposing edges, the load damper system again comes into use in that it is moved with its high friction over a path of X + Y while no torque is building up. The steep spring characteristic curve is then passed through after the path X + Y. The subsequent reverse movement is exactly the opposite of the rotational movement just described. After a single rotation into the load range, the torque and frictional force trends illustrated in Figure 2 and provided with arrows are produced.

Owing to the idling path which acts during the build-up of torque and has a value of X + Y and in which only the frictional force of the load damper system..., an improved transition from the idling damper system to the load damper system is achieved and the undesirable start up and stopping noises as well as the clutch engagement jolts are avoided.

Figure 3 shows how the principle according to Figure 1 can be transposed with reference to a clutch disk 1 shown in detail. All concentric parts of the clutch disk 1 are arranged rotatably round an axis of rotation 9. The internal hub 8 is provided with internal teeth for non-rotatable application onto a gearshaft (not shown). It is connected radially outwardly via the clearance teeth 7 to the external -hub 5. The clearance a-mounting toc'l +"'2 determines the range of action of the idling damper system. The hub disk 6 having apertures 18 for receiving torsion springs 10 for the load damper system is designed integrally with the external hub 5. The friction lining carrier 3 and the covering disk 4 which are non-rotatably connected and are kept apart by spacer rivets 15 are arranged on either side of the hub disk 6. The friction lining carrier 3 is connected radially externally via rivets 16 to spring segments 17 and friction linings 2. Radially inside the torsion springs 10, between the friction lining carrier 3 and the covering disk 4 as well as the hub disk 6, there is arranged the friction device for the load damper system consisting of two friction rings 21, a supporting ring 22 as well as a Belleville spring washer 23. The idling damper system is arranged to the side of the friction lining carrier 3 and therefore spatially outside the load damper system, a hub disk 11 of this system being arranged rigidly on the internal hub 8 and its two covering disks 12 and 13 being non-rotatably connected to the external hub 5. Damper springs 14 for the idling damper system are arranged in corresponding apertures in the hub disk 11 and the covering disks 12 and 13. This construction is basically also carried out with the load damper system, the damper springs 10 also being inserted in apertures 19 and 20 of friction lining carrier 3 and covering disk 4. An appropriate arrangement of the apertures and the springs according to Figure 1 produces a mode of operation corresponding to the torque and frictional force trend of Figure 2. The external construction of the clutch disk 1 is not linked to the system in Figure 3. The same mode of operation can be achieved if the idling damper system is spatially integrated into the load damper system as, for example, according to German patent applications Nos. 3 345 409 and 3 415 927.It is also pointed out that the load damper system can be equipped with different groups of springs which are used in succession so that the spring characteristic curve is increasingly steep in a stepwise manner. In such a case, all apertures for the load springs in the hub disk.-of the external hub, should be greater at least by the amount X + Y, the subsequently used springs requiring correspondingly greater apertures.

Claims

CLAIMS:

1. A clutch disk assembly for a motor vehicle friction clutch having a torsional vibration damper which comprises an idling damper system (5, 8, 14; 11-14) dimensioned for idle running as well as a load damper system (3, 4, 6, 10, 21-23) dimensioned for load running, wherein both the idling damper system (5, 8, 14; 11-14) and the load damper system (3, 4, 6, 10, 21-23) have input parts (3, 4, and 5; 12, 13) and output parts (6, and 8: 11) which are rotatable relative to one another round a common axis of rotation (.9), are torsionally elastically connected to one another via separate spring means (10 and 14) and at least the load damper system (3, 4, 6, 10, 21-23) comprises a friction device (21-23) and wherein the idling damper system (5, 8, 14; 11-14) is effective solely in an idling relative rotational angle range allocated to idle running and the load damper system is effective in a load relative rotational angle range outside the idling relative rotational angle range, wherein the spring means (10) of the load damper system (3, 4, 6, 10, 21- 23) is allocated an idling rotational path (X, Y) in the region of the transition from the idling relative rotational angle range into the load relative rotational angle range, solely the friction device (21-23) of the load damper system (3, 4, 6, 10, 21-23) being effective in this - idling rotational path (X, Y).

2. A clutch disk assembly as claimed in claim 1, wherein the idling relative rotational angle range is limited by stops (7) which bridge over the idling damper system (5, 8, 14, 11-14) outside the idling relative rotational angle range, and wherein the spring means of the idling damoer system k3, 4, 6, 10, 21-23) comprises several springs (10), in particular helical springs, which are all held in mutually allocated apertures (18, 19, 20) of the input part (3, 4) and the output part (6) of the load damping system (3, 4, 6, 10, 21-23), wherein the dimensions of the apertures (18, 19, 20) provided in these parts (3, 4, 6) in the peripheral direction are selected for each of the springs (10) of the load damper system (3, 4, 6, 10, 21-23) such that the spring (10) rests in one of the parts (3, 4) essentially without clearance in the peripheral direction and in the other part (6) at least with a clearance corresponding to the idling rotational path (X, Y) in the peripheral direction in its apertures (18, 19, 20).

3. A clutch disk assembly as claimed in claim 2, wherein the springs (10) of the load damper system rest without clearance in the apertures (19, 20) of the input part (3, 4) and with the idling rotational path clearance (X, Y) in the apertures (18) of the output part (6).

4. A clutch disk assembly as claimed in claim 2 or 3, wherein the load damper system (3, 4, 6, 10, 2123) comprises at least two spring stages which come into use in succession during a relative rotation between its input part (3, 4) and its output part (6), of which the springs (10) rest in mutually allocated apertures (18, 19, 20) of the input part (3, 4) and the output part (6) of the load damper system (3, 4, 6, 10, 21-23) and wherein the springs (10) of at least one of the spring stages rests in apertures (18, 19, 20 of the input part (3, 4) or of the output part (6) which are enlarged in the peripheral direction in addition to the idling rotational Dath clearance (X, Y) by a further predetermined clearance relative to the apertures of the other respective part.

5. A clutch disk assembly substantially as described with reference to Figure 3 of the accompanying drawings.