GB2181817A

GB2181817A - Torsional vibration damper

Info

Publication number: GB2181817A
Application number: GB08624337A
Authority: GB
Inventors: Franz Hartig; Harald Raab; Matthias Fischer
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1985-10-19
Filing date: 1986-10-10
Publication date: 1987-04-29
Also published as: GB8624337D0; DE3546918C2; FR2588929A1; DE3537324C2; DE3537324A1; FR2588929B1; GB2181817B

Abstract

The invention relates to the simplified production of an idling system in a torsional vibration damper. The basis is adopted of a torsional vibration damper in which the hub disc 5 of the under-load system engages, with play in the circumferential direction, with a toothing 4 in the hub 2. The improvement is to be seen in that the toothing 4 of the hub 2 is made lengthened in the axial direction and in the region beside the hub disc 5 of the under-load system the toothing is used directly for the actuation of the torsion springs 12 of the idling system 11, or a separate hub disc 17 with a corresponding internal toothing is set without play in the circumferential direction upon the prolonged toothing of the hub. <IMAGE>

Description

SPECIFICATION Torsional vibration damper The invention relates to a torsional vibration damper, especially for clutch discs of motor vehicle clutches, consisting inter alia of a hub with internal toothing for rotation-fast engagement in an external toothing of a shaft, an external toothing on the hub for engagement of an internally toothed hub disc, with play in the circumferential direction between the two toothings, cover plates to both sides of the hub disc and torsion springs with steep spring characteristic curves in windows of the cover plates and the hub disc, possibly a friction device for the under-load range, a torsion damper device for the idling range with torsion springs of flat spring characteristic curve, which is effective in the range of the play between the two toothings, the torsion springs being arranged approximately in the space between the toothings and the one cover plate and radially within the torsion springs with steep spring characteristic curve while the torsion damper device for the idling range consists of at least two spring-guiding components of which one output part is arranged fast.in rotation on the hub and one input part engages by means of axially extending noses fast in rotation in openings of the hub disc and the torsion springs engage in corresponding openings of both components.

A torsional vibration damper of the abovestated style of construction is known for example from Fed. German Inspection Document No. 3,345,409. The function of this torsional vibration damper conforms entirely with the expectations made of it.

It is the problem of the present invention to improve torsional vibration dampers of the stated kind to such effect tha they can be produced more simply and fitted more easily.

In accordance with the invention this problem is solved by the characteristic of the Main Claim. Due to the configuration in accordance with the invention of the external toothing of the hub, in one production operation, beside the torque introduction of the under-load range that of the idling range can also take place by way of the same toothing. Therefore the hitherto necessary separate securing of the torque output part of the idling system is eliminated.

In accordance with Sub-Claims 2 and 3 it is here also possible for the second zone of toothing of the hub to be formed directly as output part of the idling system, which makes the production of a separate component superfluous; it is however also possible for the output part of the idling system to comprise an internal toothing with which it engages without play in the circumferential dirction in the second toothing zone of the external toothing of the hub. Such a formation has the advantage that the output part of the idling system can be produced as regards form and material for this specific task independently of the hub of the torsional vibration damper.

Further advantageous embodiment possibilities are laid down in the Sub-Claims.

The invention will next be explained in greater detail by reference to examples of embodiment. Individually: Figure 1 shows the partial longitudinal section through a torisional vibration damper; Figure 2 shows the partial longitudinal section through a torsional vibration damper in which the output part of the idling system is made in one piece with the hub; Figure 3 shows the section C-C of two different embodiments, namely in the right half according to Fig. 2 and in the left half according to Fig. 4; Figure 4 shows the partial longitudinal section B-B according to the left half of Fig. 3; Figure 5 shows the partial longitudinal section through a further variant; Figure 6 shows the section E-E according to Fig. 5.

Fig. 1 shows the partial longitudinal section through a torsional vibration damper 1. This comprises a hub 2 which is provided with an internal toothing 3 for rotation-fast connection with a shaft (not shown). The hub 2 comprises an external toothing 4 having two different zones. In the first toothing zone 18 a hub disc 5 is fitted on with an internal toothing 13 in a manner in which play in the circumferential direction is provided which fixes the range of action of a torsional damper device for the idling range. The hub disc 5 comprises in its radially outer region windows 6 for the reception of torsion springs 7 with steep spring characteristic curves. On both sides of the hub disc 5 there are arranged cover plates 8 and 9 which likewise comprise windows 10 for the reception of these torsion springs 7.One of the two cover plates is formed, in a manner not further shown, as carrier for the friction linings for the introduction of the torque. The torsion damper device 11 for the idling range is arranged approximately in the region between the toothings 13 and 18, the cover plate 9 and radially within the torsion springs 7. In the present case it is assembled in principle like the torsion damper device for the under-load range. It consists of a hub disc 14 which engages with an internal toothing 1 5 without play in the circumferential direction in the second toothing zone 19 of the hub 2. The hub disc 14 has windows 17 for the reception of torsion springs 12 with flat spring characteristic curve. To both sides of the hub disc 14 the input parts for the idling system are provided, namely in the form of two cover plates 21 and 23.The cover plate 23 lies directly against the hub disc 5 and comprises windows 25 for the torsion springs 7. The cover plate 21 lies on the side of the hub disc 14 facing the cover plate 9 of the under-load system and reaches in the axial direction by way of noses 22 into corresponding openings 49 in the hub disc 5. Thus the cover plate 21 is connected fast in rotation with the hub disc 5 and at the same time ensures the rotation-fast connection of the cover plate 23. It is here supported in the axial direction through the cover plate 23 on the hub disc 5. The cover plate 21 comprises windows 26 for the reception of the torsion springs 12. The hub disc 14 is provided with a collar 27 which protrudes in the axial direction beyond the end of the second toothing zone 19 and.there forms a friction face 44 opposite to the cover plate 9.The cover plate 21 of the idling system likewise comprises a friction face 24 opposite to the cover plate 9.

On the side of the hub disc 5 remote from the idling system a guide ring 28 is arranged in the first toothing zone 18 and is arranged in the radial direction on the hub 2. This guide ring 28 guides the mutually firmly connected cover plates 8 and 9 in the radial direction. At the same time the guide ring 28 of L-shaped formation is made similarly to a corrugated spring in such a way that it exerts an initial stress force in the axial direction, which loads the cover plate 8 away from the hub disc 5.

The supporting of this resilient force takes place from the cover plate 8, through the connection elements (not shown) on to the cover plate 9, thence through the friction face 44 of the collar 27 on to the hub disc 14 and thence by way of a stop edge 16 directly on to the external toothing 4, which is made in one piece with the hub 2. To constitute the stop edge 16 the external toothing 4, which has a uniform toothing profile over its entire axial extent, is reduced in external diameter in the second toothing zone 19 for example by swarf-removing machining. Thus the hub disc 14 can be supported on the stop edge 16 of the hub 2. Due to this arrangement a friction device is realised which is effective both in the idling range and in the under-load range.

Here not only the friction face 44 but also the guide ring 28 contributes to the generation of this friction. Preferably both the guide ring 28 and the hub disc 14 are produced each as a synthetic plastics material part. Thus not only is a simple and thus economically priced style of production guaranteed, but at the same time it is rendered possible to adapt the friction force in accordance with requirements by selection of the synthetic plastics material.

In addition to this friction arrangement, which is effective both in the idling and in the under-load range, a further friction arrangement is provided which acts only in the underload range. This consists of a friction spring 29 which is arranged between hub disc 5 and cover plate 8 and generates an initial stress force in the axial direction. Furthermore the following components participate in this friction arrangement: the cover plate 21, which is supported on the hub disc 5 and forms a friction face 24b opposite to the cover plate 9, and the cover plate 9 itself. In this underload friction arrangement the force supporting, starting from the friction spring 29, takes place by way of the cover plate 8, the cover plate 9, the friction face 24, the cover plate 21, the cover plate 23 and the hub disc 5.

This friction arrangement can be formed and attuned completely independently of the friction arrangement as described above. Here again both the friction spring 29 and the cover plate 21 are each produced advantageously as synthetic plastics material parts.

The manner of operation of the torsional vibration damper 1 is briefly as follows: Assuming a firmly held hub 2 and torque introduction by way of the two cover plates 8 and 9, in the range of the circumferential play between the inner toothing 13 of the hub disc 5 and the first toothing zone 18 of the hub 2, a loading solely of the torsion springs 12 of the idling system takes place. The hub disc 5 and the cover plates 8 and 9 and the torsion springs 7 are regarded in this range as a rigid unit, so that through the openings 49 in the hub disc 5 the noses 22 of the cover plate 21 are loaded with torque. Since the hub disc 14 of the idling system is fitted with the torsion springs 12 fast in rotation with their internal toothing 1 5 on the second toothing zone 19 of the hub 2, the torsion springs 12 are loaded.Within this range of action of the idling system a relatively low friction also acts parallel to the torque loading of the torsion springs, namely between cover plate 9 and hub disc 14 in the region of the friction face 44 for the one part and for the other part between guide ring 28 and the cover plate 8 or the first toothing zone 18. After the play between internal toothing 13 and first toothing zone 18 is taken up, the hub disc 5 is fixed in relation to the hub 2, and on correspondingly higher torque loading now the two cover plates 8 and 9 move in relation to the hub disc 5 and load the torsion springs 7. As the hub disc 5 is now stationary the torsion springs 12 of the idling system are also not further loaded. The friction in the under-load range is now composed of the friction still effective as before during operation of the idling system and additionally the friction between cover plate 21 and cover plate 9 for one part and the under-load friction spring 29 and cover plate 8 or hub disc 5 for the other part.

Due to the arrangement as described, the external toothing 4 of the hub 2 can be produced in one operation, the addendum line being subsequently reduced by swarf removal in the second toothing zone 19, in order to guarantee an axial abutment of the hub disc 14 on the stop edge 16. Thus securing of the hub disc 14 in the axial direction is not necessary.

In Fig. 2 and in the right half of Fig. 3 there is reproduced a further possible embodiment of a torsional vibration damper with the function of that already described. The torsional vibration damper 50 is reproduced in Fig. 2 as section A-A of the right half of Fig. 3. The right half of Fig. 3 shows the cross-section C-C according to Fig. 2. In the following description the constructional differences from the embodiment according to Fig. 1 are deliberately to be discussed and the components of equal construction and effect will now briefly be enumerated. As immediately visible from Fig. 3, the torsional vibration damper 50 differs in the manner of arrangement of the torsion springs 12 for the idling range from the embodiment according to Fig. 1.In the present case the torsion damper springs 12 are arranged approximately centrally of a concentric separation gap 32 between input part 33 and second toothing zone 31 of the external toothing 4 of the hub 30. For actuation the torsion springs 12 are provided with a spring holder 45 at each end, and this spring holder 45 is loaded by extensions 36 and 37 which point in the peripheral direction. In the case of the input part 33 this manner of loading is clear. However the loading by the extensions 36 of the second toothing zone 31 needs to be explained in greater detail: The external toothing 4 of the hub 30 in the original condition has a contour such as may be seen from the right half of Fig. 3.This contour is in conformity in the lower region with the first toothing zone 18 and radially outwardly has a specially formed head zone which is provided in the direction towards the spring holders 45 with the extensions 36. In this way the torsion springs 12 can be actuated directly by a component of the hub 30.

The first toothing zone 18, as may also be seen from Fig. 2, is reduced in external circumference for example by swarf-removing machining so far that the zone with the extentions 36 is completely removed. In this way in the first toothing zone 18 a quite normal toothing is produced for engagement of the internal toothing 13 of the hub disc 5 with appropriate play in the circumferential direction for the range of use of the idling system. Due to this configuration the second toothing zone 31 directly forms a friction face 42 with the cover plate 9, which together with the manner of operation of the guide ring 28 on the opposite side, as already described, generates a friction effect of the torsional damper device 53 with low friction force.

In conformity with the different actuation of the torsion springs 12, here present, the input part 33 extends over approximately the same axial depth as the second toothing zone 31.

Here the input part 33 engages likewise with several axially protruding noses 22, distributed on the circumference, in corresponding openings 49 of the hub disc 5, for rotation-fast connection. At the same time the input part 33 is supported circumferentially outside the noses 22 axially on the hub disc 5. Thus, in combination with the under-load friction spring 29, likewise already described, by way of the under-load friction face 24 a friction effect can be achieved which comes into action outside the idling range.

With the present construction it is possible, using a uniform external toothing 4 of the hub 30, both to achieve a direct actuation of the torsion springs 12 for the idling range and to actuate the hub disc 5 for the under-load range. A torsional vibration damper 50 of this style of construction makes a minimum of individual parts suffice.

In Fig. 4 the section B-B according to the left half of Fig. 3 is reproduced. This torsional vibration damper 51 resembles the construction according to Figs. 2 and 3, in the nature of the actuation of the torsion springs 12 for the idling range, but with the difference that the hub disc 38 of the torsional damper device 54 for the idling range is produced as a separate component and is set with its internal toothing 15 in play-free manner upon the second toothing zone 19 of the external toothing 4 of the hub 2.Here again-as already described with reference to Fig. 1-the external toothing 4 of the hub 2 is produced with a uniform profile, and in the second toothing zone 19 the external diameter was reduced in such a way that the hub disc 38 set on here mets a stop edge 16 on the first toothing zone 18, in order to be able to generate a low friction force by way of the friction face 44 against the cover plate 9, which force is effective in both the idling and the under-load ranges. The input part 43 does not differ in form and function from the input part 33 according to Fig. 2 and the right half of Fig. 3.

Figs. 5 and 6 show a longitudinal section and a cross-section of a further form of embodiment of a torsional vibration damper 52.

The assembly according to Fig. 5 is substantially in conformity with the design according to Fig. 4. The hub disc 40 of the ilding system is set fast in rotation by means of its internal toothing 15 on the toothing of the second toothing zone 19. Likewise the hub disc 40 is supported in the axial direction through the stop edge 16 on the hub disc 5 of the under-load system. However the arrangement and actuation of the torsion springs 12 for the idling range are different from the previous constructions. In the hub disc 40 there are arranged several windows 47 of circumferentially large formation each containing two torsion springs 12 spaced from one another in the circumferential direction. Now the input part 41 protrudes radially inwards with a nose 48 in each case-for the loading of the free ends of the two torsion springs 12. In this way during use of the torsion dam per device 55 for the idling range, in each case one of the two springs 12 is loaded and the other relieved. With regard to the longitudinal section in Fig. 5 thus no functional modifications occur compared with Fig. 4. The input part 41 is of different formation only in the view according to Fig. 6, but otherwise likewise comprises an under-load friction face 24 opposite to the cover plate 9 and likewise engages through noses 22 in openings 49 of the hub disc 5, without play in the circumferential direction, for rotation-fast entraining.

Here again the already known two mutually independently acting friction devices are provided. A detailed description of function can therefore be omitted.

Claims

1. Torsional vibration damper, especially for clutch discs of motor vehicle clutches, consisting inter alia of a hub (2) with internal toothing (3) for rotation-fast engagement in an external toothing (4) of a shaft, an external toothing (4) on the hub (2) for the engagement of a hub disc (5) with internal toothing (13) and play in the circumferential direction between the two toothings (4, 13), cover plates (8, 9) to both sides of the hub disc (5) and torsion.springs (7) with steep spring characteristic curve in windows (10 and 6) of the cover plates (8, 9) and of the hub disc (5), possibly a friction device (29, 21, 24-Fig. 1) for the under-load range, a torsion damper device (11-Fig. 1) for the idling range with torsion springs (12-Fig. 1) of flat spring characteristic curve which is effective in the region of the play between the two toothings (4, 13), while the torsion springs (12-Fig. 1) are arranged approximately in the space between the toothings (4, 13-Fig. 1) for the one part and the one cover plate (9) for the other part and radially within the torsion springs (7) with steep spring characteristic curve and the torsion damper device (11) for the idling range consists of at least two spring-guiding components (21, 23, 24-Fig. 1), of which one output part (14-Fig. 1) is arranged fast in rotation on the hub (2) one input part (21, 23-Fig. 1) engages through axially extending noses (22) fast in rotation in openings (49) of the hub disc (5) and the torsion springs (12) engage in corresponding openings (25, 26, 12-Fig. 1) of the two components (21, 23, 14-Fig. 1), characterised in that the external toothing (4) of the hub (2, 30) is made larger in the axial direction than the width of the hub disc (5) of the under-load system, so that the hub disc (5) is arranged in a first toothing zone (18) and the second toothing zone (19, 31) is formed for the torque supporting of the idling system.

2. Torsional vibration damper according to Claim 1, characterised in that the second toothing zone (31) of the hub (30) is formed directly as output part of the idling system.

3. Torsional vibration damper according to Claim 2, characterised in that the torsion springs (12) of the idling system are arranged somewhat symmetrically in relation to a separating gap (32) between toothing zone (31) of the hub (30) and input part (33) and in openings (34, 35) coinciding in the radial direction, and the openings end each in extensions (36, 37) pointing each in the circumferential direction, for the loading of the torsion springs, the extensions (36) of the second toothing zone (31) being part of the addendum line zone of the external toothing (4) and the addendum line region being reduced by swarf removal in the region of the hub disc (5) of the underload system, for the formation of the first toothing zone (18).

4. Torsional vibration damper according to Claim 3, characterised in that the input part (33) is supported circumferentially in the region outside the noses (22) axially on the hub disc (5) and forms an under-load friction face (24) opposite to the cover plate (9) allocated to it, and an under-load friction spring (29) is arranged between the hub disc and the other cover plate (8).

5. Torsional vibration damper according to Claim 4, characterised in that under-load friction spring (29) and input part (33) are preferably produced from synthetic plastics material.

6. Torsional vibration damper according to Claim 5, characterised in that the end face of the second toothing zone (31), directed oppositely to the first toothing zone (18), together with the inner side of the cover plate (9) forms a friction face (42) for the idling and under-load ranges.

7. Torsional vibration damper according to Claim 6, characterised in that an L-shaped guide range (28), which preferably consists of synthetic plastics material and is made resilient in the axial direction, is provided on the hub (30) between the first toothing zone (18) and the corresponding cover plate (8).

8. Torsional vibration damper according to one of the preceding Claims, characterised in that the output part (14, 38, 40) protrudes in the axial direction beyond the second toothing zone (19)-possibly by formation of a collar (27)-at least in the region radially within the torsion springs (12), to constitute a friction face (44) opposite to the cover plate (9) for the idling and under-load ranges.

9. Torsional vibration damper according to Claim 8, characterised in that the output part (14, 38, 40) is preferably produced from synthetics plastics material.

10. Torsional vibration damper according to Claim 9, characterised in that an L-shaped guide ring (28), which preferably consists of synthetic plastics material and is made resilient in the axial direction, is provided on the hub (2) between the first toothing zone (18) and the pertinent cover plate (8).

11. Torsional vibration damper according to Claim 10, characterised in that the input part (21, 41, 43) is supported circumferentially outside the noses (22) axially on the hub disc (5) and forms opposite to the associated cover plate (9) an under-load friction face (24), and an under-load friction spring (29) is arranged between the hub disc and the other cover plate (8).

12. Torsional vibration damper according to Claim 11, characterised in that the underload friction spring (29) and the input part (21, 41, 43) are preferably produced from synthetic plastics material.

13. Torsional vibration damper as claimed in Claim 1 substantially as described with reference to Fig. 1, Fig. 2, Figs. 2 and 3, Figs. 2 and 4 or Figs. 5 and 6 of the accompanying drawings.