GB2179119A

GB2179119A - Torsional vibration damper

Info

Publication number: GB2179119A
Application number: GB08619089A
Authority: GB
Inventors: Johann Hayen; Alfred Schraut; Helmuth Weissenberger
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1985-08-09
Filing date: 1986-08-05
Publication date: 1987-02-25
Also published as: GB2179119B; DE3528662C2; FR2586073A1; GB8619089D0; DE3528662A1; FR2586073B1

Abstract

In a torsional vibration damper wherein the torsion springs 10 for the idling range are arranged within torsion springs 9 for the under-load range, the idling springs protrude at least in one direction beyond the springs for the under-load range and are effective alone by the amount of their over-hang. They are supported in the circumferential direction through spring dishes 13 which extend axially and are fixed in the radial direction in the hub discs 2, and are fixed in the axial direction by closed outward bulges 11, 12 of the windows which hold the under-load springs in the cover plates 4,5. <IMAGE>

Description

SPECIFICATION Torsional vibration damper The invention relates to a torsional vibration damper, especially for clutch discs of motor vehicles. From German Publication Specification No. 3,433,903 a torsional vibration damper is known, consisting of a hub for rotationfast connection with a gear shaft, a hub disc, cover plates arranged to both sides of the hub disc, windows being provided in hub disc and cover plates for the reception of torsion springs which consist of a plurality of first springs which are guided by outwardly domed pockets in the cover plates and of at least one second spring which is made smaller in diameter, possesses a flatter characteristic curve and is arranged in the interior of one of the first springs.On the basis of this prior art it was the task of the present invention to develop a torsional vibration damper which, with low expense and with low space requirement works satisfactorily over the entire torque course.

This problem is solved in accordance with the invention by the features of the main claim.

By the inclusion of the springs for the lowest torque range spatially within the springs for the higher torque range and by the supporting in accordance with the invention of the weaker springs through spring dishes it is possible on the one hand to achieve a satisfactory guidance and loading of the weaker and stronger springs and on the other hand to utilise the space radially within the circle of arrangement of the spring arrangement for example for the optimum accommodation of the friction devices. In this case the inner springs are loaded through spring dishes which are guided radially both in the middle disc and in the side discs and are held in the axial direction by pockets of the side discs.

Further advantageous examples of embodiment appear from the Sub-Claims.

The invention will next be explained in greater detail by reference to two examples of embodiment.

Individually: FIGURE 1 shows the partial section through a clutch disc; FIGURE 2 shows in the left half the partial section B-C and in the right half the partial elevation A according to Figure 1; FIGURE 3 shows the partial section through a side disc according to Figures 1 and 2; FIGURE 4 shows the partial section through a clutch disc with different assembly.

Figure 1 shows the longitudinal section through the upper half of a clutch disc with a torsional vibration damper. The latter consists of a hub 1 which is arranged fast in rotation with an internal toothing on a gear shaft (not shown). The hub 1 is firmly connected with two axially mutuaily opposite side discs or cover plates 4 and 5, through securing rivets 23.

A middle disc or hub disc 2 is rotatably arranged in the space between the two cover plates 4 and 5. In the present case it consists of several individual parts assembled in layered manner; it can however consist of a one-piece (homogeneous) component. The hub disc 2 carries in the radially outer region friction linings 8 by way of which a torque can be introduced and passed on to the gear shaft. The two cover plates 4 and 5 are provided with pockets 11 and 12 domed outwards away from one another, in which torsion springs 9 in the form of helical springs are situated. These torsion springs 9 are illustrated only in chain lines in order to improve the clarity of the representation. The torsion springs 9 are here arranged both in windows 20 of the hub disc 2 and in windows 21 of the cover plates 4 and 5.Details of this arrangement appear especially from Figure 2.

This shows on the left the section B-C from Figure 1 and on the right the partial elevation according to the arrow A in Figure 1. The torsional vibration damper comprises several springs 9 distributed in the circumferential direction, which transmit the torque in the case of higher angles of rotation and in the case of greater moments. The windows 21 in the cover plates 4 and 5 are produced in the circumferential direction by approximately radial punched incisions 16 which are cut with spacing from one another into the cover plates, the pockets 11 and 12 for the springs 9 being domed to the exterior. The configuration of the punched incisions 16 will be explained in greater detail below. In at least one of the torsion springs 9 a further torsion spring 10 is housed. The diameter of the torsion spring 10 is so selected that it finds space within the torsion spring 9.It has a substantially flatter spring characteristic curve and effects the springing of the torsional vibration damper in the idling range. At least at one end region the torsion spring 10 reaches in the circumferential direction out beyond the end region of the corresponding torsion spring 9. For this purpose a corresponding outward bulge is provided in the hub disc 2.

In the latter there is also situated a spring dish 13 which extends parallel with the rotation axis 22 of the clutch disc, has a width approximately of the diameter of the torsion spring 10 and the length of which is so adapted that it is axially guided in the clear internal width oi the pockets 11 and 12. Between the torsion spring 10 and the spring dish 13 a plane 17 of separation results which extends in each case parallel with the rotation axis 22. This plane of separation coincides with the punched incision 16. The spring dishes 13 are provided each with a longitudinally extending corrugation 18 pointing away from the torsion spring 10. This corrugation 18 serves both for the stiffening of the spring dish 13 and for its radial guidance in a corresponding aperture 19 in the hub disc 2 or apertures 25 in the cover plates 4 and 5.The punched incisions 16 in their middle region approximately follow the contour of the spring dish 13 pointing away from the spring 10 and form tabs 15 which axially fix the spring dishes 13. The guidance of the torsion spring 10 in the radial direction is effected through guide edges 14 in the hub disc 2 which merge into the aperture 19 for the spring dish 13. The arrangement in the cover plates appears from Figure 3, which shows the cover plate 5 in section. The pocket 12 is bent out of the plane of the cover plate 5 so that the circumferential end edges of the window 21 lie free towards the torsion spring 9. Furthermore the aperture 25 may be seen in which the spring dish 13 is radially guided with its corrugation 18.As may be seen especially from Figure 2 on the right, elevation A, the punched incision 16 in the cover plate 5 and also in the cover plate 4, in the rest position of the torsional vibration damper, is remote in the circumierential direction from the torsion spring 9 by the distance by which the torsion spring 10 reaches out of the interior of the torsion spring 9. Since the punched incision 16 at the same time forms the abutment edge of the window 21 for the torsion spring 9, the amount of the overhang of the torsion spring 10 at the same time determines the range of action of the idling system in which only the torsion spring 10 is effective.

The function of the torsional vibration damper according to Figures 1 to 3 is as follows: Assuming a firmly held hub 1 and a torque loading of the hub disc 2 in the clockwise direction according to Figure 2, the torsion springs 9 are initially not stressed, since they can move in the cover plates 4 and 5, which are likewise held fast. The torsion spring 10 is loaded through the hub disc 2 and the spring dish 13, arranged oppositely to the clockwise direction, and is supported through the spring dish 13, lying in the clockwise direction, in the windows 21 of the cover plates 4 and 5.

This movement is completely accompanied by the torsion springs 9 without them being subjected to compression. In this first range of rotation angle thus only the torsion spring 10 is effective and it effects a very flat spring characteristic curve. After a predetermined angle of rotation the end zonea of the torsion springs 9, lying forward in the direction of rotation, come into contact with the windows 21 in the cover plates 4 and 5. From this moment onwards both the torsion springs 9 and the torsion springs 10 are loaded with torque. As a result of the considerably steeper spring characteristic curve of the torsion springs 9, the transmittable torque per angle of rotation increases considerably.

As may be seen from Figure 1, a friction device 24 can be arranged in the space radially within the circle of arrangement of the torsion springs, which device can utilise this space advantageously since the torsion spring for the idling range is arranged concentrically with the torsion spring for the under-load range.

Figure 4 shows the upper half of a longitudinal section through a clutch disc in which the torsion springs have been omitted for the sake of simplicity. In this clutch disc the hub 1 and the hub disc 3 are of one-piece construction, while the cover plates 6 and 7 together with the friction linings 8 can carry out a relative rotation in relation to the hub lon torque loading. In this construction again the torsion springs for the idling range, arranged in the torsion springs for the under-load range, are supported through spring dishes 13 on the hub disc 3 and the cover plates 6, 7, while the spring dishes 13 are axially and radially fixed analogously with Figure 1.

It is not necessary to discuss details separately, since the function and assembly correspond in principle to the constructions hitherto. Here again the space iadially within the circle of arrangement of the torsion spring arrangement can be utilised especially for friction devices.

Claims

1. Torsional vibration damper, especially for a motor vehicle clutch disc, comprising: a) two disc units (2, 4, 5; 3, 6, 7) rotatable in relation to one another about a common rotation axis (22), of which a first disc unit comprises two side discs (4, 5,; 6, 7) firmly connected with one another with axial spacing from one another and a second disc unit comprises a middle disc (2;3) arranged axially between the two side discs (4, 5; 6, 7), b) several helical first springs (9) offset in relation to one another in the circumferential direction which are arranged in windows (20) of the middle disc (2; 3) and engage in windows (21) of the two side discs (4, 5; 6, 7) for the rotationally elastic coupling of the two disc units (2, 4, 5; 3, 6, 7), the windows (21) of the tXo side discs (4, 5; 6, 7) being formed by outwardly domed pockets (11, 12) which radially guide the first springs (9), c) at least one second spring (10) rotationally elasticaily coupling the disc units (2, 4, 5; 3, 6, 7) with one another which second spring has an external diameter smaller than the internal diameter of the first spring (9), is arranged in the first spring (9) and has a lower spring rating than the first springs (9), characterised in that at least one of the ends of the second spring (10) protrudes in the circumferential direction of the disc parts (2, 4, 5; 3, 6, 7) beyond the first spring (9) enclosing it, in that the first springs (9) are arranged with play in the circumferential direction of the disc units (2, 4, 5; 3, 6, 7) in the windows (21) of one of the two disc units (4, 5; 6, 7), in that at least the end of the second spring (10) protruding beyond the first spring (9) is supported in each case on a spring dish (13) which is axially fixed in the pockets (11, 12) of the two side diacs (4, 5; 6, 7) and is radially guided in shape-engaging manner both on the middle disc (2; 3) and on the two side discs (4, 5; 6, 7).

2. Torsional vibration damper according to Claim 1, characterised in that the pockets (11, 12) of the side discs (4, 5; 6, 7) arranged axially beside the second spring (10) are limited in the circumferential direction by substantially radially extending punched incisions (16) which in their middle region form tabs overlapping in the circumferential direction with the spring dish (13) and axially fixing the latter and in their outer regions radially adjoining the tabs (15) form stop edges, co-operating with the first spring, of the windows (21) in the side discs (4, 5; 6, 7).

3. Torsional vibration damper according to Claim 2, characterised in that the outer regions of the punched incisions (18) extend substantially in an end face plane (17) of the second spring (10).

4. Torsional vibration damper according to Claim 2 or 3, characterised in that the punched incisions (16) in their middle region substantially follow the contour of the spring dish (13) remote from the second spring (10) in the circumferential direction of the disc units (2, 4, 5; 3, 6, 7).

5. Torsional vibration damper according to one of Claims 1 to 4, characterised in that the spring dish (13) comprises a stiffening corrugation (18) extending longitudinally in the direction of the rotation axis (22), which corrugation in the circumferential direction of the disc units (2, 4, 5; 3, 6, 7) points away from the second spring (10) and engages for radial guidance in matching apertures (19) of the windows (20, 21) of the middle disc 2; 3) and of the side discs (4, 5; 6, 7).

6. A torsional vibration damper substantially as described with reference to and as illustrated by any one of the embodiments shown in the accompanying drawings.