GB2207965A

GB2207965A - Friction clutch assembly

Info

Publication number: GB2207965A
Application number: GB08818471A
Authority: GB
Inventors: Reinhold Ruppel; Winfried Sturmer
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1987-08-07
Filing date: 1988-08-03
Publication date: 1989-02-15
Also published as: GB8818471D0; FR2619175A1; DE3726342A1; BR8803905A

Description

9 2Lur9 Title: Friction clutch assembly The invention relates to a clutch

assembly, consisting of two clutch discs, an intermediate plate, a presser plate, a clutch cover, a spring device for loading the presser plate in the direction towards the clutch discs, a release spring device for loading the intermediate plate in the direction towards the presset plate, a rotation-fast but axially free connection between each of the intermediate plate and the presser plate. for the one part and clutch cover for the other part, and a lever arrangement between cover, intermediate plate and presser plate for the positive disenga gement of the intermediate plate with about half the disengagement distance of the presser plate.

Such a two-disc clutch is known by way of example from German Patent Application P 35 25 486.6. In this known twodisc clutch, support levers are arranged on the external circumference of the intermediate plate, which levers extend obliquely in the direction towards the diaphragm spring and there rest on it radially between its the two circles of support. This arrangement has for example the disadvantage that it is not readily adjustable to freedom from play when the clutch is in the condition installed in the motor vehicle. Moreover the support levers are quite bulky, in order to guarantee an adequate rigidity.

It is therefore the problem of the present invention to improve two-disc clutches of the above-stated construction type to such effect that easier assembly and adjustment especially when the clutch is in the installed condition are rendered possible.

r In accordance with the invention this problem is solved by the characteristic of the Main Claim. By the arrangement of radial levers sufficient space is available for the accommodation of other important components of the clutch, as for example the tangential leaf springs. Supporting on the intermediate plate is effected by a very simple component of stable form in its loading direction, and the arrangement of the support on the cover side as an externally accessible adjusting device renders adjustment possible when the clutch is in the installed condition, and in this case the clutch disc on the fly-wheel side, with its tolerances, can be taken into consideration. In that case it is not necessary to provide large openings in the cover surrounding the clutch Dismantling and assembly of a clutch which has already run is here possible without fresh adjustment. Moreover this construction is even suitable for clutches with for example three clutch discs.

Further advantageous possible embodiments appear from the Sub-Claims. The radial levers reach with their inner ends into an opening in the presser plate and are there supported on a stop plate which is screwed in the axial direction from the exterior on to the presser plate and partially closes this opening again. With the radially outwardly pointing ends the radial levers are held in a displacement device or in an adjusting device, the radial. lever comprising at this end a nose with which it engages in a corresponding opening of an axially displaceable slider and is supported with shoulders on both sides of the nose on the radially inwardly pointing face of the slider against

I i centrifugal force. The opening of the slider forms a knifeedge and the slider serves for playfree adjustment of the radial levers in relation to this knife-edge and in relation to the support plates secured to the intermediate plate. The slider is here guided in the outer region of the cover in an axially proceeding groove and is axially adjustable and arrestable. The arresting'can be effected from radially outside by a screw, but it is also possible for a frictional-engagement connection to be provided between the sliders and the clutch cover, the displacement force of which is so great that it permits no displacement during operation of the clutch, while however a displacement can be effected in the adjustment for example by a hammer blow. In this case due to the arrangement of the sliders on the external circumference of the cover their accessibility is especially good.

The invention will next be explained in greater detail by reference to several exam,ples. Individually:

Figure 1 shows the longitudinal section C - D through a two-disc clutch for.a motor vehicle; Figure 2 shows the section A - B according to Figure 1; Figure 3 shows a longitudinal section through another form of embodiment of a clutch; Figure 4 shows the longitudinal section through a further clutch variant.

The two Figures 1 and 2 are to be considered in correlation. They show in longitu-dinal section and practically in elevation, through a sectional clutch cover, a two-disc clutch which is fitted on the fly-wheel 1 of an 4 internal combustion engine. The clutch cover 2 is screwed through an intermediate ring 3 with the f ly-wheel 1. A diaphragm spring 8 is supported with its external circumference through a support ring 27 on the clutch cover. In its middle region the diaphragm spring 8 is supported through a support ring 28 on the presser plate 4. The radially inwardly pointing spr-ing tongues 9 of the diaphragm spring 8 are loaded and pivoted in the direction of the arrow P by a release system (not shown) for the release of the clutch. Between the flywheel 1 and the spring-loaded presser plate 4 there are arranged, starting from the flywheel, a clutch disc 7, an intermediate plate 5 and a clutch disc 6. Both clutch discs 6 and 7 are arranged fast in rotation but axially displaceably on a gear shaft (not shown). The whole system is arranged symmetrically and rotatably about an axis 10 of rotation. The intermediate plate 5 is arranged fast in rotation but axially displaceably in relation to the interemediate ring 3, in a manner not further illustrated. It is here initially stressed by means -of a release spring arrangement in the direction towards the presser plate 4. Tangential leaf springs as indicated at 45 are ordinarily used for the initial stress and for the rotation-fast connection. The presser plate 4 too must be arranged fast in rotation but axially displaceably in relation to the cover 2. Here again' tangential leaf springs as indicated at 46 can be used. In the case of the presser plate 4 too it is to be ensured that in a release movement of the diaphragm spring 8 the presser plate 4 carries out a release movement either by positive 31 coupling with the diaphragm spring 8 or likewise by a release spring arrangement. This then acts likewise according to Figure 1 from left to right.

For the positive coupling of presser plate 4 and intermediate plate 5 during the engagement or disengagement action several circumferentially distributed radial levers 21 are provided which extend substantially radially. They extend, starting from the presser plate 4, in the radial direction into the cover 2. In the cover 2 for each of the sliders 12 a displacement device 11 is provided which consists of a slider 12 which as may be seen especially from Figure 2 - is axially displaceably guided in a groove 40 of the cover. The displacement device 11 further contains a clamping screw 13 which penetrates a slot 15 in the slider 12 and is secured in a welded nut 33 which is welded to the inner wall of the cover 2. The clamping screw 13 has a collar with which it can be tightened on the cover 2. It acts upon one or more dished springs 14, achieving a corresponding initial stress force between the slider 12 and the cover 2. The slider 12 penetrates the cover 2, in an abundantly dimensioned opening 18, and dips with a nose 19 into an opening 16 of the slider. This opening 16 ends, on the side of the radial lever 21 remote from the intermediate plate 5, in a knife-edge 17. With its other end the radial lever 21 is supported against the presser plate 4, namely on a stop plate 23 which is held by screws 26 on the presser plate 4 and extends parallel with the clutch discs 6 and 7. For the dipping of the radial levers 21 into the presser plate 4 corresponding openings 24 are provided which are 6 e open radially outwards and pointing in the axial direction away from the intermediate plate 5 and are partially closed again by the stop plate 23 for the formation of blind openings. For the execution of their function the radial levers 21 are further supported somewhat centrally between the stop plate 23 and the knife-edge 17 on the opposite side through-a support plate 22 on-the intermediate plate 5. The support plates 22 are of simple straight form and screwed by screws 25 from radially outwards on to the intermediate plate 5. To secure the radial levers 21 in the radial direction, for example to take up the centrifugal forces, each radial lever is provided laterally of its nose 19 with shoulders 20, and these shoulders rest on the inwardly facing face of the slider 12. Furthermore the supports 29 for the support ring 28 may be seen from the two Figures, which supports are interrupted in the circumferential direction and merge laterally into radial ribs 30 which serve for better air circulation within the clutch. These ribs 30 are interrupted in the region of the stop plates 23.

Now the function of the two-disc clutch as illustrated is as follows: In the assembly of the clutch firstly the cover 2 is completed with the diaphragm spring.8, the presser plate 4, the radial levers 21 and the displacement devices 11. Here the sliders 12 are situated in their position furthest remote from the fly-wheel 1. With. interposition of the clutch disc 6 now the intermediate ring 3 with the intermediate plate 5 secured thereto is laid upon the cover 2. Now the fitting and securing to the fly-wheel take place, with interposition of the clutch disc 7. Here -1 1 mutually corresponding bores extending parallel to the axis 10 of rotation are provided in the cover 2 and in the intermediate ring 3 for the introduction of screws. After the screwing of the cover parts with the fly-wheel 1 the presser plate 4, the clutch disc 6, the intermediate plate 5 and the clutch disc 7 lie without play against the fly-wheel 1 under the initial stress force of the diaphragm spring 8. Due to the extreme position of the sliders 12 maintained in fitting the radial levers 21 are arranged loosely in the axial direction. By a hammer blow upon the free ends of the sliders 12 these are displaced in the axial direction in the groove 40 against the friction force generated by the dished springs 14, in the direction towards the fly-wheel 1, and the radial levers 21 are clamped in without play at their three support positions. These three suppport positions are firstly the knife-edge 17, next the free end, remote from the fly-wheel 1, of the support plate 22, and the stop plate 23 on the presser plate 4. In all now succeeding release and engagemnent movements of the clutch the intermediate plate 5 is posit.ively coupled with the movement of the presser plate 4, since it is loaded by the release spring arrangement in the direction towards the presser plate 4 and thus, through the support plates 22 and the radial levers 21, is compelled to imitate a part of the axial movement of the presser plate 4. By appropriate selection of the distances between the bearing points of the radial levers 21 on the stop plates 23 and on the knife-edge 17 for the one part and of the position of the support plates 22 for the other part, the proportional ratio of the release distance v 8 - 1 of the presser plate 4 to that of the presser plate 5 can be appropriately adapted. The friction force between the sliders 12 and the cover 2 must be so high that in all operational conditions of the clutch an unintended displacement cannot take place. The intended displacement is merely the adjusting operation after the fitting of the clutch.

This adjusting operation can take place advantageously after the assembly of clutch and engine, so that the actual axial space requirement of the clutch disc 7 on the flywheel side is automatically also taken into consideration. This adjustment is possible through a relatively small opening in the cover surrounding the clutch. If the clutch is dismantled and assembled again, reusing the two clutch discs 6 and 7, readjustment is not necessary. The relatively strong clamping-in of the sliders 12 effects a very uniform wearing of the friction linings of the two clutch discs 6 and 7, whereby the life of the clutch is lengthened. Due to the simple adjustment of the displacement device 11 it is possible to permit. relatively large tolerances in all components, so that production of the clutch at worth- while price is possible.

In Figure 3 there is represented a thru st plate in which, in departure from Figure 1, the fly-wheel 1 and the clutch disc 7 on the fly-wheel side are not illustrated. This thrust plate differs from that in Figure 1 merely in that a different arrangement of the diaphragm spring 8 is -provided. The thrust plate is shown by what is called a 19pressed" clutch, in which for the release movement of the 1 9 presser plate 4 and the intermeoiate plate 5 the spring tongues 9 of the diaphragm spring 8 are loaded in the direction of the arrow P in the direction towards the flywheel (not shown). The release movement according to Figure 1 in what is called a "pulled" clutch is converse. This differerke necessitates the supporting of the diaphragm spring 8 in the region of its.external circumference on the presser plate 4 and in the region of a smaller circle on the clutch cover 2 through support rings 27 and rivet bolts 31-, Otherwise the clutch according to Figure 3 corresponds exactly to the formation and function of the clutch according to Figu res 1 and 2, while all parts have the same reference numerals and therefore the function does not need to be explained afresh.

In Figure 4 a further longitudinal section through a thrust plate of, a two-disc clutch is represented, in which the clutch actuation takes place through release levers 34. In this case too what is called a "pressed" construction style is provided. The release levers 34 are for the one part mounted pivotably about rotation axes 39 on the clutch cover 2 by means of bearing brackets 38 on a middle diameter and they engage with their external diameter by means of rotation axes 37 in bearing brackets 36 of the presser plate 4. This results, on loading through a release system (not shown) in the direction of the arrow P, in a movement of the. presser plate 4 in the direction towards the cover 2, whereby the clutch disc 6 and the clutch disc 7 (not shown) are disengaged. For the generation of the pressureapplication force here several circumferentially distributed 10 helical springs 35 are provided.

The other components of this thrust plate correspond to those of Figures 1 to 3, and they are also provided with the same reference numerals. The sole difference from the above-described embodiments is to be seen in that the adjusting device 32 does without springs and thus in the adjustment of the clutch after the first assembly an axial displacement of the sliders 12 does not alone suffice, but after the positioning of these sliders 12 the clamping screws 13 must be tightened firmly.

This construction too has the same advantages as the embodiment as described in Figures 1 to 3.

i 1

Claims

- 11 C 1 a i m s l.) A clutch assembly, comprising a) two clutch discs (7,

6), b) a clutch cover (2), c) an intermediate plate (5), axially between the two clutch discs (6, 7), which is guided fast in rotation but axially movably in relation td the clutch cover (2), d) a presser plate (4) guided fast in rotation but axially movably in relation to the clutch cover (2) on the side of one of the two clutch discs (6) axially remote from the intermediate plate (5), - e) a clutch spring device (8) acting between the clutch cover (2) and the presser plate (4), which device initially stresses the presser plate (4) axially towards the intermediate pllate (5), f) a release spring device (45) initially stressing the intermediate plate (5) axially towards the presser plate (4) g) a lever arrangement (21, 22) which couples the intermediate plate.(5) with the presser plate (4) and in the release of the presser plate (4) limits the release distance of the intermediate plate (5) to about half of the release distance of the presser plate (4), characterised in that the lever arrangement comprises a plurality of radial levers (21) distributed in the. circumferential direction of the presser plate (4), each of which is supported with its radially outer end on a circumferential wall of the clutch cover (2) and with its radially inner end on the presser plate (4) through support - 12 -.

joints (17, 19 and end of 21, 23)g in that from the intermediate plate (5) there protrude axial projections (22) which are supported, approximately in the middle between the support joints (17, 19 and end of 21, 23) of the radial levers (21), on the latter, and in that the radially outer support joints (17, 19) of the radial levers (21) are accessible and adjustable in their position in relation to the clutch cover (2) from outside the clutch cover (2). -
2.) A clutch assembly according to Claim 19 characterised in that sliders (12) accessible from outside the clutch cover (2) are axially displaceably secured on the circumferential wall of the clutch cover (2), each of which sliders comprises an opening (16) in which there engages a nose (19) protruding from the radially outer end of the radial lever (21).
3.) A clutch assembly according to Claim 2, characterised in that shoulders (20) are formed on both sides of the nose (19) on the radial lever (21) through which the lever (21) is supported radially -on the slider (12), and in that the edge of the opening (16) of the slider (12) facing axially away from the intermediate plate (5) is formed as a knifeedge (17).
4.) A clutcb Assembly according to Claim 2 or 3, characterised in that the sliders (12) are guided securely. against rotation but axially displaceably on the outside of the circumferential wall of the clutch cover (2).
S.) A clutch assembly according to Claim 4 characterised in that the sliders (12) are displaceably 0 guided in axial grooves (40) of the circumferential wall.
6.) A clutch assently according to one of Claims 2 to 5, characterised in that the sliders (12) are secured on the clutch cover (2) by means of screw connections (13, 33) accessible from outside the clutch cover (2).
7.) A clutch assembly gccording to one of Claims 2 to 6, characterised in that the sliders (12) are fixed in the axial direction on the clutch cover (2) by means of a friction-force connection (13 14 33).
8.) A clutch assembly ac.ording to one of Claims 1 to 7, characterised in that each radial lever (21) engages with its radially inner end in a radially outwardly open blind opening (24) of the presser plate (4) and is radially supported in the blind opening (24).

assembly
9.) A clutch characterised in that the blind opening is formed by an aperture (24) of groove form on the side of the presser plate (4) axially remote from the intermediate plate (5) and a stop plate (23) covering the aperture (24) and secured to the presser plate (4).
10.) A clutch assembly according to one of Claims 1 to 9, characterised in that the projections of the intermediate plate (5) are formed as support plates (22) screwed to the external circumference of the intermediate plat e (5).

according to Claim 87
ll.) A clutch assembly substantially as described with reference to the example shown in Figpres 1 and 2, Figure 3 or Figure 4 of the accompanying drawings.

Published 1988 at The Patent Office. State House, 66 71 High Holborn, London WC1R 4TP. Further copies may be obtained from The Patent Office, Seles Branch, St Mary Cray. Orpington, Kent BRS 3RD. Printed by Multiplex techniques ltd. St Mary Cray, Kent. Con. 1187.