GB2310270A

GB2310270A - Clutch disc assembly with a two-stage idling device

Info

Publication number: GB2310270A
Application number: GB9627111A
Authority: GB
Inventors: Norbert Ament
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1996-02-16
Filing date: 1996-12-31
Publication date: 1997-08-20
Anticipated expiration: 2016-12-31
Also published as: DE19605721C1; FR2745050B1; FR2745050A1; BR9700981A; ES2147685A1; GB2310270B; ES2147685B1; GB9627111D0

Description

1 2310270 "Clutch disc assembly with a two-stat!e idlinp- device" This

invention relates to a clutch disc assembly, especially for use in the ffiction clutches of automobiles.

A known clutch disc assembly, described in DE OS 4031762, employs a hub which rotates with a drive shaft and which is keyed with teeth to a hub disc acting as the output of a torsion load damper. A pair of cover plates disposed either side of the hub disc function as the load damper input and are fixed together. One of the cover plates carries the friction finings. Spring elements set in windows in the cover plates and the hub disc resiliently couple the cover plates to the hub disc. An idling damper is disposed axially between one of the cover plates and the hub disc. The idling damper is composed of a further hub disc and at least one further cover plate likewise coupled together with springs set in windows in these components. The further cover plate acting as the input component of the idling damper is torsionally keyed +1.0 the hub disc acting as the output component of the load damper and is supported axially against the hub disc. The further hub disc acting as the output component of the idling damper is torsionally keyed to the hub. Frictional force generating devices define the load range and the idling range and include a control unit or plate which is axially frictionafly clamped between the input and output components of the idling damper.

In this known clutch disc assembly, the control unit is subjected on its two sides to different ffictional forces. In conjunction with a predetermined spring clamping, it is thus possible to generate a different, delayed and angle-dependent frictional force.

2 It is an objective of the present invention to create an improved clutch disc assembly with a similar two-stage idling fliction device, which is economical and space-saying and in which the frictional forces can be adjustable quite independently of one another.

According to the invention, there is provided a clutch disc assembly, especially for the friction clutches of automobiles, said assembly comprising a load damper input component having ffiction finings, a load damper output component and spring elements between the input and output components for permitting relative resilient rotation between the components under torque loading, a hub for rotationally locked mounting on a shaft which defines an axis of rotation, a set of teeth between the load damper output component and the hub with play in the radial direction, an idling damper disposed axially between the input and output components of the load damper, the idling damper having an input component which is rotationally locked to the output component of the load damper and is supported axially against the latter, an output component which is rotationally locked to the hub and spring elements between the input and output components of the idling damper for permitting relative resilient rotation therebetween and friction force- creating devices for defining the load range and idling range comprising a control plate which is axially frictionally clamped between the input and output components of the idling damper, wherein a) the spring elements of the idling damper are disposed in windows in the output component of the load damper, the control plate co-operates with at least one of the idling spring elements which comes into action after a first angle of twist (a, B) of the idling damper, and the window in the output component for the at least one idling spring element is larger in the circumferential direction at least by the value of the first angle of twist, 3 b) the control plate engages with at least one control lug into the window between the at least one spring element and an edge of the window and the control plate is connected to the input and output components of the load friction damper via a fliction device, which is capable of being adjusted independently.

With this form of construction assurance is provided that the two-step or two-stage idling spring device is combined with a two-step or two-stage ffiction device, it being possible for the second friction step to be adjusted and tuned independendy of all other frictional and spring forces. Such a possibility aiTords to the developer the necessary freedom of choice when a vehicle is particularly sensitive in the tuning of the idfing noise. The location for mounting the friction device can be easily adapted to the local circumstances in that the torsionally keyed connection can be made outside the bearing surface of the control plate.

It is proposed that the control plate is constructed preferably radially outwardly extended and is in play-free connection there, via axially extending connecting elements, to the friction device. A possibility for accommodating the friction device win be present in many cases, especially radially outside the control plate particularly having regard to the space that otherwise would remain unused due to the circular cross- section of the torsion springs in the region of the one or the other cover plate. It is, however, also possible to provide this friction device radially inside the control plate, since the necessary space may be available also in this region.

4 The control plate preferably possesses two mutually opposite pairs of windows, which are angularly displaced from one another by about 900, and the one pair has circumferentially at least the length of the idling springs, which are active already in the range of the angle of torsion (a, 8) and the other pair has circumferentially the length of the idling springs which come into action after the range of the angle of torsion (a, 13). The control plate can be provided, in the circumferential end range of these windows, with axially projecting control lugs. With this construction it is ensured in simple manner that the use of the second frictional stage takes place purely as a function of the angle of rotation and that this effiect is retained even with reversed direction of rotation.

The control plate can have, preferably, two radiafly outwardly open apertures distributed at the circumference and radially outside the windows, into which a substantially axially extending connecting element of the friction device engages without play. By this torsionally keyed connection, simple to manufacture, the friction device is coupled to the control plate.

In known manner, the load damper input component can be in the form of cover plates, which are firmly connected to each other and are held spaced apart, and the output component can be in the form of a hub disc between the cover plate which is connected by the set of teeth with play to the hub. The idling damper is then disposed between one of the cover plates and the hub disc of the load damper. The idling damper can consist of at least one further cover plate as an input component which, optionally with the incorporation of a friction material, bears against the inner face of the one cover plate and is axially supported via axially bent-over noses against the hub disc and is torsionally keyed to the latter. A further hub disc acting as the output component of the idling damper is seated and torsionally keyed on the hub. By this construction assurance is provided that the friction device present for the load range excludes influencing of the control plate, so that the control plate is clamped only by the spring device of the basic friction device.

It is furthermore proposed that the control plate possesses, circumferentially ofiEset from the apertures, zones of reduced diameter to permit the noses of the cover plate of the idling damper to pass. By this construction, a very compact arrangement in the radial direction is made possible.

It is also proposed that the axial clamping of the control plate between the further hub disc of the idling damper and the cover plate disposed on the side of the hub disc of the idling damper remote fl-om the hub disc of the load damper can be provided by the force of the springs for the basic ffiction device, which is effective over the entire angle of twist. By this arrangement, on the one hand the axial space demand can be clearly established by the control plate and additional tolerances by safety spacings can thus be avoided.

It is, however, also possible for the axial clamping of the control plate to take place between the further hub disc of the idling damper and the hub disc of the load damper by the force of the springs for the basic fliction device that are active over the entire range of the angle of twist. In this manner, the distance between the two hub discs can be exactly regulated by the arrangement of the control plate. In advantageous manner, the inwardly situated cover plate of the idling damper can then be on-titted, allowing the springs of the idling damper to be governed by corresponding pockets in the hub disc of the load damper.

6 The invention will now be explained in more detail with reference to the following description:

In the accompanying drawings:

Figure 1 is a longitudinal section through the upper half of a clutch disc assembly constructed in accordance with the invention; Figure 2 is a section taken along the fine A-B of Figure 1; and Figures 3 to 5 are somewhat enlarged partial longitudinal sections corresponding to Figure 1 and representing further embodiments of the invention.

The clutch disc assembly 1 depicted in Figure 1 possesses a hub 7, which is mounted concentrically to an axis of rotation 8, and is torsionally keyed to a gear or t-ansmission shaft, not shown. In its radially outer region, the hub 7 possesses an external set of teeth 11. A hub disc 6 has an internal set of teeth 12 which meshes with the teeth 11 and forms therewith a tooth system 10 which possesses a predetermined amount of radial play. The hub disc 6 is the output component of a torsional load damper which comprises also cover plates 4 and 5 disposed on either side of the hub disc 6 acting as the input component of the load damper. The cover plate 4 is provided with resilient lining supports 3 and friction linings 2 disposed radially outwardly of the cover plate. 4. The two cover plates 4, 5 are rotationally locked to one another in a manner not further shown and held apart at a certain axial spacing. In corresponding windows of the cover plates 4, 5 and of the hub disc 6, load springs 9 are disposed, which are preferably constructed as helical cod springs disposed generally tangentially about the axis of rotation 8. Radially inside the load springs 9 and between the hub disc 6 and the cover plate 5, an idling torsion damper is disposed. This damper consists of a further hub disc 7 15, which is torsionally locked by a set of teeth 33 to a portion, of reduced external diameter, of the external set of teeth 11 of the hub 7. On either side of the further hub disc 15, further cover plates 13, 14 are disposed, by which idling springs 16, 26 are mounted and controlled. The springs 16, 26 are mounted in windows in the further disc 15 and the further cover plates 13, 14. The presence of the cover plate 13 is not absolutely necessary, because this function can be undertaken also by the hub disc 6, by the latter having appropriate windows or pockets for mounting the springs 16, 26. The cover plate 14 is provided with axially cranked noses 19, which on the one hand make a torsionally locked connection with the hub disc 6 and on the other hand create an axial support against the hub disc 6 or against the cover plate 13, so that a space free of axial force results in the axial intermediate space between the cover plate 14 and the hub disc 6. By this axial support, the forces that are exerted by a load friction device are conducted away. This load friction device consists of two friction rings 22 and 23, a spring 21 and of a load ring 20. The friction ring 23 is disposed between the cover plate 14 and the cover plate 5 and the fiction ring 22 is disposed between the load ring 20 and the hub disc 6. The load ring 2Cr is connected in a torsionally locked but axially displaceable manner to the cover plate 4 and is loaded by the spring 2 1. The load friction device 20, 21, 22, 23 is elfective only when the play in the tooth system 10 has been used up and a relative rotation between hub disc 6 and the cover plates 4 and 5 takes place. A basic friction device is also provided, which consists of a bearing 17 which supports and guides the cover plate 4 in a radial direction relative to the hub 7, and a spring 18, which is disposed between a shoulder of the external set of teeth 11 of the hub 7 and the hub disc 15. The hub disc 15 is torsionally locked to the hub by the set of teeth 33, but is guided for displacement in the axial direction. The spring 18 acts, via the hub disc 15, and a control plate or unit 28 - to be described later - on the cover plate 14, via the ffiction ring 23 on the cover plate 5, via connecting elements, not illustrated, onto the 8 cover plate 4 on the opposite side and thence via the bearing 17 again on the external set of teeth 11 of the hub 7. As a consequence of the axial bearing of the cover plate 14 via its noses 19 against the hub disc 6 a space, free of axial forces, is provided for the hub disc 15. Hence, the load fliction device cannot influence the basic friction device and the two can be adjusted independently of one another.

The clutch disc assembly 1 also possesses an additional fliction device, which will be explained in more detail in connection with Figure 2. As shown in Figures 1 and 2, the assembly 1 employs a control plate 28, which is axially clamped between the hub disc 15 and the cover plate 14 of the idling damper by the force of the spring 18. This control plate 28 is, in the present case, extended radially outwards and is in connection with the additional friction device composed of a spring 24 and a fliction ring 25. The additional ffiction device is so governed that it comes into use within the working range of the idling damper. For this purpose, two different types of springs 16, 26 are provided in the idling damper as shown in Figure 2. The springs 16 are disposed in windows 32 in the hub disc 15 and the cover plates 13, 14 so that in the at-rest position of the entire system they are disposed play-free and thus immediately come into action when the idling damper is in use. The springs 26 are disposed in windows 30 and are so arranged that they come into use after a predetermined angle of rotation a, B respectively, still within the working range of the idling damper. For this purpose, the windows 30 in the hub disc 15 are circumferentially of greater size than the corresponding windows 32 for the springs 16. Furthermore, the control plate 28 is provided with axially projecting control lugs 29, which engage into the windows 30 of the hub disc 15 in such a manner that in the at-rest position of the entire system they possess a circumferential spacing corresponding to the non-loaded springs 26. The windows 30 in the hub disc 15 are however larger in the circumferential direction by the angle value a, 13 respectively than 9 the circumferential extent of the springs 26 in the at-rest position inclusive of the circumferential extent of the control lugs 29. In the control plate 28 itself, windows 3 1, 32 are also disposed for receiving the springs 16, 26. The windows 32 are for the springs 16, which are identical to the corresponding windows 32 in the hub disc 15 and in the cover plates 13, 14 for these springs. The windows 31 for the springs 26, correspond to the windows 30 in the two cover plates 13 and 14. It can furthermore be seen from Figure 2 that the control plate 28 is provided, in the region of its outer periphery, preferably in the region of the individual springs 16, 26, with apertures 34, which preferably are open on the radially outer side, and into which noses 27 engage without play in the circumferential direction. These noses 27 are a part of the additional friction device, consisting of the friction ring 25 and the spring 24. The last two names components bear in the axial direction, on the one hand against the cover plate 14 of the idling damper and on the other hand against the inner face of the cover plate 5 of the load damper. From Figure 2 it can furthermore be seen that the control plate 28 possesses, circumferentially ofiEset from the apertures 34, regions 38, which are reduced in diameter so that here the noses 19 of the cover plate 14 can be conducted past.

The operation of the clutch disc assembly 1 is as follows: When a torque is introduced via the fliction linings 2 and with the hub 7 fixed, the load damper behaves, in the working range of the idling damper, as a stiff unit. The two cover plates 4 and 5 together with the hub discs 6 and 9, thus move synchronously together with the cover plates 13 and 14 and the two friction rings 22 and 23. The control plate 28 also participates in this motion and twists, with generation of fliction force, relative to the hub disc 15, which is torsionally locked to the hub 7. This entrainment takes place by the relatively high friction force of the components 24 and 25. The control plate 28 is loaded by the spring 18, which creates a ffictional contact between the external set of teeth 11 of the hub 7 and the bearing 17, and also exerts an axial force on the hub disc 15, which by the axially loose connection via the set of teeth 33 creates the clamping of the control plate 28. After travelling through a part of the idling range corresponding to a or 13, that is to say in the one or the other rotational direction, the control lugs 29 of the control plate 28 come to bear against the windows 30 in the hub disc 15. In this movement sequence, only the two idling springs 16 have been loaded, which are disposed in identical windows 3 2 of hub disc 15 and cover plates 13, 14. After abutment of the control lugs 29 against the end zones of the windows 30 of the hub disc 15, an additional compression takes place of the springs 26, so that the spring characteristic increases at a steeper angle. Simultaneously, the control plate 28 comes to a stop circumferentially relative to the hub disc 15, so that from now onwards the additional friction de-vice is effective. This device consists of the spring 24 and the ffiction ring 25, which is coupled torsionally locked by its noses 27 to the control plate 28. Thus the ffiction ring 25 stops relative to the cover plate 5 and creates additional friction. Preferably, the spring 24 is also torsionally locked to the ffiction ring 25, so that a frictional force is created also at the point of contact between the spring 24 and the cover plate 14. With the coming into play of the two idling springs 26, a jump in frictional force is thus created, it being possible for the magnitude of this additional friction to be tuned completely independently of all other components creating a friction force. The free space for the spring 24 and the ffiction ring 25 is determined by the high force of the spring 21 and the axial space of the friction ring 23. As a further increase in the torque occurs, the set of teeth 10 becomes blocked, that is to say the internal teeth 12 of the hub disc 6 and the external teeth 11 of the hub 7 strike one another. The idling damper is thereby bridged over by this contact and is no longer moved in the circumferential direction, but now the resilience and also the friction of the load damper comes into play. From now onwards, the two cover plates 4 and 5 rotate relative to the hub disc 6, so that 11 the load springs 9 are loaded and the two friction rings 22 and 23 provide their flictiongenerating action. In parallel to this, the basic friction device comprising the spring 18 and the bearing 17 continues in operation.

In the reverse movement within the range of action of the idling damper, the compressed springs 26 first of all ensure that the additional friction device continues to function through the components 24 and 25, until the springs 26 are destressed. Only then will the control plate 28, together with the cover plates 13, 14 and 5, execute an equal rotational movement so that the frictional action of the components 24 and 25 is then cancelled.

In Figure 3, a partial longitudinal section is shown through another clutch disc assembly in which the additional fliction device in the range of angular rotation of the idling damper is modffied. The components making up the additional friction device are composed of a transmission ring 35, a spring 24 and a friction ring 25, all disposed on the side of the hub disc 6 opposite the idling damper. The components 35, 24, 25 are situated in diametric region radially outside the components of the load friction device, consisting of the spring 21, the load ring 20 and the friction ring 22. Since the axial distance from the control plate 28 is now increased in relation to the Figure 1 embodiment, the additional friction device is provided with the separate transmission ring 35, which is preferably made of metal and which penetrates, with the axially projecting lugs 27, through corresponding openings of the hub disc 6 and creates, in the region of the idling damper, a torsionally locked connection to the control plate 28. A single component, e.g. of plastics corresponding to Figure 1, might not be of sufficient strength. All the other components in this Figure 3 construction correspond in construction and function to those of Figure 1.

12 Figure 4 also shows a partial longitudinal section through a further clutch disc assembly wherein, in contrast to Figure 1, the complete idfing damper with the additional friction device has been placed on the left side, that is to say the crank shaft side of the internal combustion engine. The components of the load friction device are on the opposite side. The operation of the clutch disc assembly is thereby unchanged. In Figure 4, however, the bearing 17 for the cover plate 4 has been extended radiaIly outwards by an extension 37 and this extension forms part of the load fliction device. The axial alignment of the two cover plates 4 and 5 with respect to the hub 7 is provided by a ffiction ring 36, which is situated between the cover plate 5 and the external set of teeth 11. The friction ring 36 is a part of the basic ffiction device, the frictional clamping being provided by the spring 18 between the hub disc 15 of the idling damper and the external set of teeth 11. The other components are already known from Figure 1 and correspond also to the fanction described above.

The clutch disc assembly according to Figure 5 dilfers from the forms of construction corresponding to Figures 1 to 4 in that the control plate 28 is situated between the hub disc 15 of the idling damper and the hub disc 6 of the load damper and the inwardly located cover plate of the idfing damper provided in the other forms of construction is now omitted. In this way an axiafiy space-saving construction is obtained. Furthermore, in this construction, the hub disc 15 is circumferentiafiy and axially fwn-dy connected to the hub 7, which can be achieved for example, by a peening operation. The spring 18 for the basic fliction device is situated directly between the hub disc 15 and the bearing 17 of the cover plate 4 so the spring 18 and the bearing 17 form parts of the basic ffiction device. The other components correspond in their form and function to the already described arrangements. In all the Figures 1 to 5, the fliction ring 25 is guided in the 13 radial direction on one Of the cover plates 4 or 5, a separate step or shoulder being provided for this purpose on the cover plate 4, 5. The axially extending noses 27 of the friction rings 25 simultaneously centre the control plate 28. In the case of Figure 3, the fliction ring 25 is tightened together with the transmission ring 35 to form one unit, so that here also the control plate 28 is guided in the radial direction by the ffiction ring 25.

14

Claims

Claims

1. A clutch disc assembly, especially for the ffiction clutches of automobiles, said assembly comprising a load damper input component having fliction linings, a load damper output component and spring elements between the input and output components for permitting relative resilient rotation between the components under torque loading, a hub for rotationally locked mounting on a shaft which defines an axis of rotation, a set of teeth between load damper output component and the hub with play in the radial direction, an idling damper axially between the input and output components of the load damper., the idling damper having an input component which is rotationally locked to the output component of the load damper and is supported axially against the latter, an output component which is rotationally locked to the hub and spring elements between the input and output components of the idling damper for permitting relative resilient rotation therebetween and friction force- creating devices for defining the load range and the idling range comprising a control plate which is axially frictionally clamped between the input and output components of the idling damper, characterised in that:

a) the spring elements (26, 16) of the idling damper are disposed in windows (32, 3 0,3 1) in the output component (15) of the load damper, the control plate (28) co-operates with at least one of the idling spring elements (26) which comes into action after a first angle of twist (a, B) of the idling damper and the window (30) in the output component (15) for the at least one idling spring element is larger in the circumferential direction at least by the value (a, B), is the control plate (28) engages with at least one control lug (29) into the window (30) between the at least one spring element (26) and an edge of the window (30) and, c) the control plate (28) is connected to the input and output components (14,15) of the load fliction damper via a fliction device (24, 25), which is capable of being adjusted independently.

A clutch disc assembly according to claim 1, wherein the control plate (28) is connected to the friction device (24, 25) via axially extending connecting elements (27).

A clutch disc assembly according to claim 2, wherein the control plate (U) possesses two sets of windows (31, 32) which are offset through about 90' from one another, each window of one set of windows (32) extending circumferentially at least to the length of the other spring element (16) which are already active in the range of angular rotation (a, 13) and each window of the other set (3 1) extends circumferentially by the length of and at least one spring element (26) which come into action after the range of angular rotation (a, 13) and the control plate (28) is provided, in the circumferential end zone of the other set of windows (3 1), with axially projecting control lugs (29).

4. A clutch disc assembly according to claim 3, wherein the control plate (28) has at least two radially outwardly open apertures (34) disposed radially outside the windows (3) 1, 32), into which the axially extending connecting element (27) of the fliction device (24, 25) engage without play.

16 5. A clutch disc assembly according to any one of claims 1 to 4, wherein the input component of the load damper consists of two cover plates (4, 5), which are firmly connected to each other and held apart from one another, the output component of the load damper is a hub disc (6) disposed between the cover plates (4, 5), and the idling damper is disposed between one of the cover plates (5) and the hub disc (6) of the load damper and consists of at least one further cover plate (14) acting as an input component for the idling damper, the further cover plate (14) being supported against an inner face of the one cover plate (5) and is rotationally locked and axially supported via axially bent-over noses (19) against the hub disc (6) and a further hub disc (15) which is rotationally locked on the hub (7).

6. A clutch disc assembly according to claim 5, wherein a ffiction ring (23) is interposed between the further cover plate (14) and the one cover plate (5).

7. A clutch disc assembly according to claim 5 or 6, wherein the control plate (28) possesses regions (3 8) of reduced diameter to allow the passage of the noses (19) of the further cover plate (14) of the idling damper.

8. A clutch disc assembly according to claim 7 wherein the control plate (28) is clamped axially between the further hub disc (15) of the idling damper and the cover plate (14) disposed on the side of the further hub disc (15) remote from the hub disc (6) of the load damper by means of a spring (18) of a basic friction device, which is active over the entire range of angular twist.

9. A clutch disc assembly according to claim 7 wherein the control plate (28) is clamped between the further hub disc (15) of the idling damper and the hub disc (6) of 17 the load damper by means of a spring (18) of a basic friction device, which is active over the entire range of angular twist.

10. A clutch disc assembly substantially as described herein with reference to and as illustrated in any one or more of the Figures of the accompanying drawings.