GB2340579A

GB2340579A - Torsional vibration damper

Info

Publication number: GB2340579A
Application number: GB9918434A
Authority: GB
Inventors: Klaus Steinel; Michael Grosse-Erdmann
Original assignee: Mannesmann Sachs AG
Current assignee: ZF Friedrichshafen AG
Priority date: 1998-08-12
Filing date: 1999-08-04
Publication date: 2000-02-23
Anticipated expiration: 2019-08-04
Also published as: SE9902744D0; SE523097C2; SE9902744L; FR2782360B1; GB2340579B; DE19836478B4; FR2782360A1; DE19836478A1; GB9918434D0

Abstract

A torsional vibration damper for use in a motor vehicle power train is incorporated into a clutch disc assembly which has an inner hub (1) on which an external hub (9) is rotatable through a limited angle. At least two peripherally acting spring systems (10) are deformed relative to the hub (1) during operation and are arranged axially outside the region of annular module (4). External engagement devices (12) for spring elements (13) are non-rotatably connected to the hub (1) and internal engagement devices (11) for the spring elements (13) are connected to the external hub (9). Friction devices (8), (123) and (124) are provided, and the coil spring elements (13) may be replaced by any elastic material, for example rubber.

Description

2340579 Torsional vibration damper for use in the pover train off a motor

vehicle The present invention relates to a torsional vibration damper for use in the power train of a motor vehicle.

Torsional vibration dampers are required for damping the torsional vibrations induced mainly in internal-combustion engines. In addition to creating roaring sounds in the vehicle body, torsional vibrations also produce noise in subsequent shifting and differential gears. The elastic forces typically used to absorb torsional vibration and to deliver a torque which is as uniform as possible must, on the one hand, be sufficiently low for effective damping but, on the other hand, absorb high accelerations or forces. High deflection and therefore large torque angles of the torsional vibration damper aretherefore desirable.

Torsional vibration dampers with high maximum transmissible torques which have good response behaviour and are comparatively compact can be produced using springs connected in parallel. Torsional vibration dampers with double or multiple spring systems coupled in parallel are known, for example, from DE 31 50 877 Al. A clutch disc assembly with torsional vibration dampers is disclosed in which the torsional vibrations of the engine are to be suppressed by two or more substantially identical torsional vibration dampers connected in parallel. Each of these torsional vibration dampers comprises an annular flange for the drive side and two annular flanges for the driven side and a system of spiral springs connected in series. Two friction devices which generate hysteresis torques as a function of the torque angle are also provided. In addition to the high production costs, a 2 clutch disc assembly of this type has much greater dimensions in both the radial and the axial direction. The mass also increases significantly.

It is an object of the present invention to provide a torsional vibration damper which comprises springs connected in parallel but is much more compact, lighter and cheaper to produce than is possible with the state of the art.

According to the present invention a torsional vibration damper for use in the power train of a motor vehicle, comprises a hub mounted non- rotatably with respect to an axis of rotation, a multi-part annular component which is fastened rotatably around the axis of rotation on said hub and at least two peripherally acting spring systems which are deformed against the hub during torsion of the annular component, wherein external engagement means for spring elements of the spring system are non-rotatably connected to the hub axially outside the region of the annular component and at an axial distance therefrom, the annular component has internal engagement means for the spring elements axially on the external faces and the spring systems are arranged axially outside the region of the annular component.

The annular component or module can have a radially very compact construction if the spring systems are arranged axially outside it. Spaces for receiving the spring elements, of the type required in torsional vibration dampers with completely or partially internal spring systems, can also be dispensed with. Spring systems fastened on external faces of the annular component also have the advantage that the torsional vibration dampers with two or more spring systems connected in parallel can be produced inexpensively from parts used for producing those with only one spring system (or with 3 two spring systems connected in series).

In this respect, spring systems which are substantially the same or identical can preferably be used which, in addition to the aforementioned advantages, are also stressed uniformly owing to the uniform flow of force as ensured, so the stress on the individual parts can be reduced. Components which are typically highly stressed such as teeth can therefore be produced in a desirable manner. The particularly preferred arrangement of spring systems symmetrical about the plane of rotation, which are substantially the same or identical, is particularly distinguished in this respect.

In one advantageous design, at least one of the spring systems is loaded not when the torsional vibration damper is at rest, but only from a defined higher torsion. Loading can also be angularly offset, for example to produce different characteristic curves. Thus, for example, at least two chambers can be formed by the reciprocally rotatable spring element engagement means and these chambers can be given different sizes in the rest position. If the spring systems are then equipped with identical springs, the spring system is loaded with small engagement devices even at small torque angles. Conversely, spring elements with different spring constants can obviously also be used.

In a further advantageous design, the torsional vibration damper can be provided with at least one friction device. If the friction device cooperates with one of the spring systems, it can easily be adapted to the respective requirements. This can be achieved by a suitable combination of the friction device with one of the aforementioned spring systems.

In a further advantageous design, the double or multiple 4 spring systems are so designed that, even toward the maximum anticipated torque, small torques lead to significant torsion of the torsional vibration damper. As the relatively high torques which can be transmitted even by comparatively small spring systems are a significant advantage of a plurality of spring systems connected in parallel, a torsional vibration damper of this type can have a very compact construction. In a preferred embodiment, the above-mentioned spring systems are designed as idle-motion dampers. These comparatively low torques necessitate relatively small spring forces. The correspondingly small spring elements require hardly any additional space in the arrangement shown here.

In a further preferred embodiment, the spring systems act as a pre-damper during operation of auxiliary units. The parallel arrangement of the spring systems allows high torque angles as weaker spring elements can be deformed more markedly so the drag moments required for auxiliary drives can be transmitted at the same time if the engine vibrations are well isolated.

Furthermore, the torsional vibration damper can be connected in series with an additional spring system designed for a further range of applications. Therefore, the double or multiple spring system is not loaded by the corresponding possibly harmful - forces if it is protected from excessive twisting, for example by stops.

In an advantageous design, this further spring system is arranged radially outside the multi-part spring system as there is more space available over the greater radius, in particular in the peripheral direction, and large spring elements can therefore also be accommodated without difficulty.

In a preferred embodiment, this further spring system is designed as a load damper. The multi-part spring system can therefore be substantially protected from being loaded by high torques. An altogether wider range of torsional vibrations can therefore be covered.

The invention may be understood more readily, and various other aspects and features of the invention may become apparent, from consideration of the following description.

The construction and operation of embodiments will now be described in more detail hereinafter, by way of examples only, and with reference to the accompanying drawings, in which:

Figure 1 is an end view of part of a clutch disc assembly which has an embodiment of the torsional vibration damper radially internally and a load spring arrangement connected in series therewith radially externally; Figure 2 is a sectional view taken along line A-A of Figure 1; Figure 3 is a sectional view taken along line B-B of Figure 1; Figure 4 is a longitudinal section of a further clutch disc assembly which also has an embodiment of the torsional vibration damper radially internally and a load spring arrangement connected in series therewith radially externally; Figure 5 is a sectional view of part of a further clutch disc assembly which has only one embodiment of the torsional vibration damper and Figure 6 are schematic end views showing the external and internal engagement means.

6 The clutch disc assembly shown in Figures 1 to 3 has an inner hub 1 with inner teeth 2 for non-rotatable and coaxial connection to a gear shaft (not shown) extending in the direction of an axis of rotation 3. An external hub 9 is keyed to the inner hub 1 with inter-engaging teeth 16. Two cover plates 5 and 6 non-rotatably connected to one another are elastically connected to a hub disc 7 via a load spring arrangement 15. A friction device 8 is provided between the hub disc 4 and the cover plates 4, 5. The parts 5, 6, 7, 8, 9 and 14 form an annular module 4 which is arranged on the hub 1 so that it can be twisted round the axis of rotation 3 within predetermined limits. In the preferred embodiment shown here, the limits of torsion are defined by the circumferential backlash in the teeth 16 between the inner hub 1 and the external hub 9. Axially on either side of the annular module 4 are arranged two substantially identical spring systems 10 acting as torsional vibration dampers. Each spring system 10 has an internal engagement means 11 and an external engagement means 12. The internal engagement means 11 is non-rotatably connected to the cover plates 4 and 5 and the external hub 9, preferably by riveting but also by other methods such as welding. The external engagement means 12 is non-rotatably connected to the inner hub 1, the axial movement of the external engagement means 12 being prevented in that it engages with a shoulder on the hub 1 and is preferably caulked thereon. The respective internal engagement means 11 and external engagement means 12 are reciprocally rotatable round the axis of rotation 3 and are elastically connected to one another by means of spring elements 13. Spiral springs are preferably used as spring elements 13 in this embodiment, but any elastic components such as rubber elements can also be used just as satisfactorily.

7 As shown in Figure 2, the at least one of the dampers 10 cooperates with a friction device 17. The friction device 17 essentially consists of friction linings 123 non-rotatably connected to the internal engagement means 11 via a ring 122 and friction linings 124 non-rotatably connected to the external engagement means 12.

In this embodiment, the annular external hub 9 is arranged to partially rotate on the inner hub 1 and is non-rotatably connected to the two annular cover plates 5 and 6. The cover plates 5 and 6 are elastically connected to the hub disc 7 by means of peripherally acting spring elements 14 of the load spring arrangement 15.. The friction device 8 is in engagement with axial interstices between the hub disc 7 and the cover plates 5 and 6.

During operation, undesirable torsional vibrations produced by an internal combustion engine are transmitted to the discshaped module 4 via friction linings fastened on the hub disc 7 and high torsional accelerations are damped by the load spring arrangement 15. During idling, the torsional accelerations are comparatively low and the load spring arrangement 15 quasi rigid. The relatively weak torsional vibrations during idling are absorbed by the pre-damper which consists of two substantially identical spring systems or dampers 10 connected in parallel in the preferred embodiment shown in Figure 1. The maximum torque angle of the torsional vibration damper can be defined here by the torsional backlash of the teeth 16 between the hub 1 and the external hub 9, which gives the spring arrangements 10 the freedom to pivot to a certain extent. The torsional backlash is used up on attainment of a predetermined torque between the hub 1 and the disc-shaped module 4, so the torque is transmitted via the teeth 16.

8 Figure 4 shows a further clutch disc assembly with a different embodiment of the torsional vibration damper. The differences from the clutch disc assembly shown in Figures 1 to 3 are substantially restricted to the construction of the annular module 4. In this embodiment, the friction linings 18 are_ fastened on the cover plate 5 via a friction lining carrier. The engine torque therefore passes initially to the cover plate 5 and thence via the spring element 14 to the hub disc 7. Teeth 16 with torsional backlash which allow freedom to pivot to a predetermined extent are provided between the hub disc 7 and the hub 1. The hub 1 and the hub disc 7 are connected via two peripherally acting spring systems 10. The spring systems comprise, -inte-r alla, two annular engagement means 11 and 11a which are non-rotatably connected to one another and of which at least one is non-rotatably connected to the hub disc 7 while a further annular engagement means 12 is non-rotatably connected to the hub 1 via teeth.

As in the first embodiment, the spring systems 10 absorb the torsional vibrations during idling. If a defined torque is exceeded and the torsional backlash of the teeth 16 used up between the hub 1 and the hub disc 7, the torque is transmitted from the hub disc 7 to the hub 1 via the teeth 16.

The torsional vibration dampers shown in Figures 1 to 3 and in Figure 4 are preferably both designed as predampers. Once the predetermined torque angle has been used up, a load spring arrangement connected in series with it is loaded. However, the construction shown here is not absolutely essential. For example, the double or multiple torsional vibration damper could just as well be designed as a load spring arrangement and be arranged axially outside the annular component.

9 Figure 5 shows a further design in the form of a clutch disc assembly having a torsional vibration damper which consists of a respective spring system 10, whereas a further spring arrangement connected in series is dispensed with. The multipart torsional vibration damper is preferably designed as a predamper. A load spring arrangement can then be provided in a further component of the power train.

Figure 6 shows examples of external and internal engagement means 11 and 12 for the spring system 10. The associated spring elements 13 are located in the engagement orifices 121 in the assembled state. If, as in the present case, individual engagement orifices 121 are larger than the spring elements 13 in the undeformed state, the corresponding spring elements 13 are not loaded in the vicinity of the rest position of the torsional vibration damper. A corresponding opposing force occurs only after a defined torque angle when one or more of the spring elements 13 are moved onto one of the radially extending edges of the engagement orifices 121. On the other hand, it the engagement orifices 121 are shorter than the spring elements 13 in the rest state, an opposing force occurs during each rotation. Any number of linear or progressive characteristic curves can therefore be produced by a suitable combination. In this case, the spring elements 13 initially act in the shorter orifices 121 whereas the entire opposing force is present with a large torque angle.

Spiral springs have been used to produce the spring elements 13 and 14 in all preferred embodiments shown here. However, the invention can be implemented with any elastic material. Furthermore, the peripheral elasticity is decisive for damping torsional vibrations. However, spring systems which, for example, are also capable of absorbing radial forces can also be combined with the torsional vibration damper proposed here.

List of reference numerals 1 inner hub 2 inner teeth 3 axis of rotation 4 annular component/module cover plate 6 cover plate 7 hub disc 8 friction device 9 external hub spring system 11 engagement means 11a engagement means 12 engagement means 13 spring element 14 spring element spring system 16 teeth 17 friction device 18 friction lining 19 teeth 112 fastening orifice 121 engagement orifice 122 ring 123 friction lining 124 friction lining 771

Claims

1. A torsional vibration damper for use in the power train of a motor vehicle, said damper comprising a hub (1) mounted non-rotatably with respect to an axis of rotation (3), a multi-part annular component (4) which is fastened rotatably around the axis of rotation (3) on said hub (1) and at least two peripherally acting spring systems (10) which are deformed against the hub (1) during torsion of the annular component (4), wherein external engagement means (12) for spring elements (13) of the spring system are non-rotatably connected to the hub (1) axially outside the region of the annular component (4) and at an axial distance therefrom, the annular component (4) has internal engagement means (11) for the spring elements (13) axially on the external faces and the spring systems (10) are arranged axially outside the region of the annular component (4).

2. A torsional vibration damper according to claim 1, wherein the spring systems (10) are at least substantially similar.

3. A torsional vibration damper according to claim 1, wherein the spring systems (10) are identical.

4. A torsional vibration damper according to claim 2 or 3, wherein the spring systems (10) are arranged symmetrically with respect to a plane of rotation.

5. A torsional vibration damper according to one of the preceding claims, wherein at least one of the spring systems (10) is not loaded when the torsional vibration damper is at rest.

12

6. A torsional vibration damper according to any one of the preceding claims, wherein at least two of the spring systems (10) are loaded when mutually offset at an angle.

7. A torsional vibration damper according to one of the preceding claims, wherein at least two chambers are formed by the engagement means (11) and/or (12) and are of different sizes for receiving or deforming the spring elements (13) of the spring arrangements (10).

8. A torsional vibration damper according to any one of the preceding claims, and further comprising at least one friction device (8) for cooperating with at least one of the spring systems.

9. A torsional vibration damper according to any one of the preceding claims, wherein the spring systems (10) allow significant torsion of the annular component (4) against the hub (1) far below the expected maximum torques.

10. A torsional vibration damper according to claim 9, wherein the spring systems (10) act as an idle-motion damper device.

11. A torsional vibration damper according to claim 9 or 10, wherein the spring systems (10) are able to transmit, in particular, also the torques expected during operation of auxiliary units.

12. A torsional vibration damper according to any one of the preceding claims, wherein the spring systems (10) are connected in series with a further spring system (15).

13. A torsional vibration damper according to claim 12, 13 wherein the further spring system (15) is arranged radially outside the first-mentioned spring systems (10).

14. A torsional vibration damper according to claim 12 or 13, wherein the further spring system (15) acts as a load spring arrangement.

15. A torsional vibration damper according to claim 1, wherein the annular component (4) comprises an annular external hub (9) which is arranged rotatably on the hub (1) and is non-rotatably connected to two annular cover plates (5, 6), the cover plates (5, 6) being elastically connected to the hub disc (7) by means of peripherally acting spring elements (14), the cover plates (5, 6) are associated with each of the spring systems (10) which comprises at least one peripherally acting spring element (13), the associated internal engagement means (11) is fastened on the cover plates (5, 6) and the associated external engagement device (12) is fastened on the hub (1) and arranged on the axially outwardly directed faces of the cover plates (5, 6)

16. A torsional vibration damper according to claim 15, wherein the internal engagement means (11) is fastened on the respective cover plates (5, 6) by riveting.

17. A torsional vibration damper according to one of the preceding claims, wherein the external engagement means (12) is fastened on the hub (1) by caulking.

18. A torsional vibration damper or a clutch disc assembly incorporating such a damper substantially as described with reference to and as illustrated in any one or more of the Figures of the accompanying drawings.