GB2044865A

GB2044865A - Clutch

Info

Publication number: GB2044865A
Application number: GB8007329A
Authority: GB
Original assignee: Fichtel and Sachs AG
Current assignee: ZF Sachs AG
Priority date: 1979-03-21
Filing date: 1980-03-04
Publication date: 1980-10-22
Also published as: GB2044865B; FR2452029A1; DE2910979C2; JPS55129625A; JPH0150769B2; DE2910979A1; FR2452029B1

Abstract

Release levers (46) of a clutch are provided with wear-resisting pads (54) of porcelain, ceramics or sintered material for engaging a release thrust bearing. The clutch may include two friction discs (20, 22) with porcelain facings for connecting a drive housing to concentric output shafts, each disc cooperating with a respective presser plate operable by respective levers fitted with pads as above. Alternatively, both discs may transmit the drive to a single output shaft. <IMAGE>

Description

SPECIFICATION Clutch The invention relates to a clutch arrangement for installation between a drive disc and a gearing, comprising a clutch housing for securing to a drive disc, at least one clutch disc within this clutch housing and connectable with a drive-output shaft leading to the gearing, at least one presser plate within the clutch housing, at least one spring arrangement for pressing the presser plate against the clutch disc and for pressing the clutch disc against a drive face arranged fast in rotation on the clutch housing or the drive disc, and disengaging levers pivotably mounted on the clutch housing with operative faces for a disengaging bearing and with engagement parts for engagement with the presser plate.

In known clutch arrangements of this kind it has appeared that the operative faces of the disengaging levers on which the disengaging bearing acts wear relatively quickly if these operative faces are formed from the usual metallic materials.

Starting from the fundamental idea of a lengthening of the life of the clutch arrangement, the invention is based upon the problem of reducinng the wear on the operative faces of the disengaging levers.

To solve this problem it is proposed in accordance with the invention that the operative faces of the disengaging levers are formed on operative parts of porcelain, ceramics or sintered material, which operative parts are secured on the disengaging levers.

As ceramic materials there may be considered especially an aluminium oxide-ceramic material such as Rapal-100.

As sintered materials there may be considered especially the material Sint-A 10 in accordance with DIN Standard.

The formation of the operative faces in accordance with the invention on special operative parts which in turn are secured to the disengaging levers permits of producing the disengaging levers themselves from cheap materials with labour-saving production methods; especially it is possible to produce the disengaging levers from sheet metal by stamping, pressing or drawing.

The securing of the operative parts on the disengaging levers can likewise be effected in a simple manner especially by clamping, preferably by leaf springs. The leaf springs can here engage in slots of the operative parts which are let into the operative bodies from the respective operative face.

The fitting of special operative parts on the disengaging levers provides the prerequisite for an especially interesting further development of independent inventive significance: It becomes possible, by permission of a slight movement of the operative parts in relation to the disengaging levers, to compensate for defects of alignment and/or angle between the clutch axis and the disengager axis, and thus largely to render harmless radial relative movements between the co-operating parts of the disengaging levers and of the disengager as regards wear phenomena.

This can be effected especially in that the disengaging parts are tiltable in abutment sockets of the disengaging levers about axes placed tangentially of the rotation axis of the drive disc.

A measure of further development of independent inventive significance aiming likewise at the prolongation of the life consists in that the clutch disc is provided with friction linings of porcelain, ceramics or sintered material.

The use of disengaging levers of cheap material rendered possible by the basic idea of the invention necessitates further considerations regarding the mounting of the disengaging levers on the clutch housing in order on the one hand to guarantee long life even at the bearing points and on the other hand to fulfil the requirement for production at favourable cost even at the bearing points.On the basis of these considerations, according to a further development of independent inventive significance it is proposed that the disengaging levers with flanges substantially parallel to one another and to the clutch axis are mounted by two bearing bolts each between ribs of the clutch housing which are substantially parallel to one another and to the clutch axis likewise, each of which bolts engages with a non-circular head in a correspondingly non-circular aperture of the respective flange and with a cylindrical section in a bore of the respective bearing rib, the heads of the two bearing bolts of a disengaging lever on the oner hand abutting on the associated bearing ribs and on the other hand being secured against axial displacement by a securing element which is detachably secured on the respective disengaging lever.The securing elements can here be secured on the disengaging levers at the position of the connection of the engagement parts with the disengaging levers, preferably using the connection means which connect the engaging parts with the disengaging levers.

The measures according to the invention as discussed so far are fundamentally applicable to the most various clutch types, especially motor vehicle clutches. The life-prolonging measures however acquire special significance in clutches for utility vehicles of all kinds, especially heavy freight vehicles and agricultural tractors. In such vehicles according to experience the clutches are subjected to especially heavy stresses and furthermore specifically in such high-greade investment goods long life is expected.For this reason the measures proposed in accordance with the invention are proposed especially for double action and dual clutches, that is to say a clutch which is characterised in that it is formed iwth two clutch discs, two presser plates between these clutch discs and a spring arrangement between the presser plates, this spring arrangement pressing the two presser plates away from one another against the two clutch discs and the two clutch discs each against a drive face of the drive disc and a drive face of the clutch housing, and in that two groups of disengaging levers are provided, a first group to act upon the first presser plate close to the drive disc and a second group of disengaging levers to act upon the second presser plate remote from the drive disc.The application of the fundamental idea of the invention to this type of clutch requires measures of further development therein at different points.

The disengaging levers of the first group may be considered first; radially outside the bearing axes, tie bolts act upon these which engage at the other end on the first presser plate. The production of these disengaging levers from cheap materials with manufacturing methods of favourable cost leads to tolerances which necessitate a well thought-out adjustment technique which however is again of favourable cost.

On the basis of this consideration it is proposed that the tie bolts are provided on the disengaging lever side with a threading, carry an adjusting nut on this threading and that between this adjusting nut and the respective disengaging lever an abutment plate lies which at the same time serves as securing element for the bearing bolts of the disengaging lever. The adjusting nut can here be formed as a compression nut, having a deformable collar for engagement with a noncircular surface of the respective tie bolt. In order to gain a low-wearing, easily adjustable connection between disengaging lever and tie bolt which permits the angular movements between disengaging lever and tie bolt, here the disengaging levers of the first group can abut with a convex curvature on the respective abutment plate.

During operation with the clutch engaged the disengaging levers are subject to a centrifugal force which can effect a displacement of the disengaging levers out of the normal rest position, unless the centre of gravity of the disengaging levers lies in the same radial plane in which the tangential pivot axis of the disengaging lever on the clutch housing also lies. This condition for the position of the centre of gravity cannot always be observed.

It is therefore further proposed that the disengaging levers are pressed against the respective adjusting nut by an elastic presser device which bears on the first presser plate. The elastic presser device can comprise a compression spring enclosing the respective tie bolt and in series therewith a pressure sleeve preferably of synthetic plastics material which abuts against the disengaging lever, preferably in the region of a concave curvature of the disengaging lever complementary to the convex curvature.

Now the expedient measures of further development on the second group of disengaging levers should be considered. The adjustment problems considered above are here solved in a manner in which threaded bores are formed on the disengaging levers of the second group and thrust bolts are inserted into these threaded bores and act radially within the pivot bearings of these disengaging levers on the second presser plate. If the disengaging levers consist of sheet metal, the threaded bores for the thrust bolts cannot readily be prepared. It is therefore further proposed that the threaded bores each extend into a neck which is swarflessly formed on the respective disengaging lever of the second group, in the course of the production operation.

In order that no excessive bending forces on the thrust bolts themselves and on the disengaging levers have to be tolerated due to long thrust bolts, it is further proposed that each of the thrust bolts abuts against a dog of the second presser plate which, starting from the second presser plate, points in the axial direction towards the respective disengaging lever. This also provides a favourable prerequisite for a measure which is also expedient on these disengaging levers, to prevent excessive action of centrifugal force.

Such a measure can consist in that with the thrust bolts on the clutch housing there are associated abutment faces against which the thrust bolts can place themselves if the disengaging levers are loaded in a direction opposite to the direction of action of the disengager, by centrifugal force or by grasping of the disengaging levers. The abutment faces can here be formed by pockets of the clutch housing.

The thrust bolts can be secured on the disengaging levers by lock nuts; a securing element for the bearing bolt pertaining to the respective disengaging lever can be clamped in here in each case between the disengaging lever and the respective lock nut.

On the disengaging levers there can also be fitted spring arches which bear on a clutch part, especially the second presser plate, and hold the disengaging levers in a rest position.

These spring arches can have the effect that the disengaging levers are always subject to a certain tension which is advantageous for the desired smooth running of the clutch. When a clutch is lifted it is frequently grasped by the disengaging levers. The elastic presser devices proposed for the first group of disengaging levers and the spring arches proposed especially for the second group at least partially take up the forces then introduced into the disengaging levers, and finally the thrust bolts can also come to abut on their associated abutment faces.

The spring arches can likewise be clamped in between the disengaging levers and the respective lock nuts.

The spring arrangement forced between the two presser plates can be formed by a diaphragm spring or dished spring which is usual per se in clutch construction. In order to obtain an abutment with low noise and wear between diaphragm spring or dished spring on the one hand and presser plate on the other, in further development according to the invention it is proposed that the diaphragm spring or dished spring comprises convexly curved abutment humps to abut on the presser plates.

The centring of the diaphragm spring or dished spring can be effected in an especially simple manner at favourable cost in that the diaphragm or dished spring is centred on at least one presser plate by at least two centring elements. According to a first alternative the centring elements can here be formed by axially directed splined pins which are received each by a bore of a presser plate and engage in an aperture of the diaphragm or dished spring, preferably in a slot between two successive tongues; according to a second alternative the centring elements can be formed by angled clipped-out portions, preferably between two successive tongues of the diaphragm or dished spring, which engage in bores of the presser plate.

The invention is explained by the accompanying Figures, wherein: Figure 1 shows the diagram of a clutch arrangement to which the proposals of the invention are applicable; Figure 2 shows a view of a clutch arrangement according to the invention in the direction of the arrow II in Fig. 1; Figure 3 shows a section along the line Ill-Ill in Fig. 2; Figure 4 shows a section along the line IV-IV in Fig. 2; Figure 5 shows a section along the live V-V in Fig. 2; Figure 6 shows a diaphragm spring of the clutch arrangement according to the invention and Figure 7 shows the centring of the diaphragm spring on a presser plate, in a configuration differing from Fig. 3.

In Fig. 1 the drive-output shaft of an internal combustion engine is designated by 1 0. A drive disc connected with this drive-output shaft is designated by 1 2. A clutch housing 14 is secured on this drive disc 12. The clutch housing 1 4 has a housing shell 1 6 and a housing cover plate 1 8. A first clutch disc 20 and a second clutch disc 22 are accommodated in the clutch housing. The first clutch disc 20 is fitted non-rotatably but axially displaceably on a first drive-output shaft 24 which leads to a gearing 26.The second clutch disc 22 is fitted fast in rotation but axially displaceably on a second drive-output shaft 28 which as hollow shaft encloses the first drive-output shaft 24 and is connected through a pair of gear wheels 30, 32 with a power take-off arrangement 34. Between the two clutch discs 20 and 22 there are arranged a first presser plate 36 and a second presser plate 38. The first presser plate 36 is pressed against the first clutch disc 20 and thus at the same time the first clutch disc 20 is pressed in frictional engagement against an abutment face 42 on the drive disc 12, by a spring arrangement 40 which is arranged between the two presser plates 36 and 38.At the same time thanks to the action of the spring arrangement 40 the second presser plate 38 is pressed against the second clutch disc 22 and thus the second clutch disc 22 is pressed in frictional engagement against a drive face 44 on the housing cover plate 18.

Thus in the condition as described hitherto both clutch discs 20 and 22 are driven by the drive disc 1 2 so that the drive-output shafts 24 and 28 are driven.

The clutch discs 20 and 22 can be disengaged from the frictional engagement with the drive faces 42 and 44. For this purpose disengaging levers are provided, namely disengaging levers 46 pertaining to a first group of disengaging levers and disengaging levers 48 pertaining to a second group of disengaging levers.

The disengaging levers 46 are mounted by first disengaging lever bearings 50 on the clutch housing; the disengaging levers 48 are mounted by second disengaging lever bearings 52 on the clutch housing. On their radially inner ends the disengaging levers 46 and 48 of both groups comprise operative parts 54. Upon these operative parts 54 there can act a disengaging bearing 56 which is displaceable in the axial direction of the clutch arrangement and consists of a bearing part 58 connected fast in rotation with a shift device and a bearing part 60 which is rotatable in relative to the bearing part 58. The bearing part 60 is intended to act directly on the operative parts 54. When the disengaging bearing 56 is shifted to the left in Fig. 1 and the rotatable bearing part 60 runs against the operative parts 54, the disengaging levers 46 and 48 are pivoted.The pivoting movement of the disengaging levers 46 is transmitted through tie bolts 62 to the first presser plate 36, so that the latter is lifted away from the first clutch disc 20. The pivoting movement of the disengaging levers 48 is transmitted through thrust bolts 64 so that the second pressure plate 38 is lifted away from the second clutch disc 22.

The clutch arrangement as described hitherto represents a so-called dual clutch. It can however also be used as a so-called doubleaction clutch by simple measures of conversion. In this case the two clutch discs 20 and 22 are connected axially displaceably but fast in rotation with the first drive-output shaft 24 and the second drive-output shaft 28 is not present. The two clutch discs 20 and 22 thus in this case serve exclusively for the transmission of the torque from the drive disc 1 2 to a drive-output shaft 24 and thus to the gearing 26.

Figs. 3 and 4 show details of the disengaging levers. The disengaging levers 46 of the first group and 48 of the second group are both produced by drawing from sheet metal.

The formation at their radially inner ends is common to the disengaging levers 46 and 48. On these radially inner ends there are formed abutment sockets 68. Operative parts 54 of porcelain, ceramics or sintered material are inserted into these abutment sockets 68.

The operative parts 54 have a curved back 72 for abutment on an abutment face 74 of the sockets 68 so that the operative parts 54 can carry out tilting movements on the abutment faces 74, namely about axes 70 which in Figs. 4 and 3 are perpendicular to the plane of the drawing and are tangential in relation to the rotation axis of the clutch arrangement.

The operative parts 54 are held by leaf springs 76 against the abutment faces 74 of the abutment sockets 68. The leaf spring 76 are secured by rivets 78 on the disengaging levers 46 and 48 and engage in slots 80 of the operative parts 54. On the operative parts 54 there are arranged operative surfaces 82 which are curved about the tilting axes 70 so that the operative parts can in practice roll between the abutment faces 74 and the rotatable bearing race 60 of the disengaging bearing 56 if there is necessity to compensate for radial displacements.

Now the mounting of the disengaging levers 46 and 48 on the clutch housing 14 should be further considered. It is sufficient to consider the mounting of the disengaging levers 46, which is quite generally designated by 50. As may be seen from Fig. 2, the disengaging levers 46 comprise flanges 88 substantially parallel to one another and also to the axis of the clutch. In these flanges 88 there are provided square apertures 90 (Fig.

4). These square apertures 90 of the flanges 88 accommodate similarly square heads 92 of bearing bolts 94. The bearing bolts 94 are inserted with cylindrical sections 96 into bores 98 of bearing ribs 100 of the housing cover plate 1 8 in such manner that they accompany the rotation of the disengaging levers 46, but are mounted rotatably in the bores 98; the heads 92 rest on the bearing ribs 100 and are held in the abutment position by securing elements 102, which are to be discussed hereinafter.

Now the co-operation of the disengaging levers 46 with the first presser plate 36 is to be considered; in this connection reference is again made to Fig. 3.

A domed portion 104, which is convex to the right and concave to the left, is formed on the disengaging lever 46 at its radially outer end outside the bearing point 50. The disengaging lever is provided in the region of this domed portion 104 with a piercing 106 which is penetrated by the tie bolt 62. The tie bolt 62 also penetrates the first presser plate 36 and has at its left end in Fig. 3 a tie bolt head 108 which abuts on the presser plate 36. The end of the tie bolt 62 to the right in Fig. 3 is provided with a threading 110. A compression nut 11 2 is screwed on to this threading.The compression nut 11 2 rests through the intermediary of the securing element 102, formed as sheet metal, against the convex side of the domed portion 1 04. The compression nut 11 2 is provided with a compressible collar 11 4 which after the adjustment of the compression nut 1 12 can be squeezed against a flat face 1 16 of the tie bolt 62 so that the compression nut 11 2 is thenceforth secured. As may be seen from Fig. 2 the securing element 102 is dimensioned in width in the region of the bolt heads 92 so that the bearing bolts 94 cannot slip out of the bores 98.

Between the concave side of the domed portion 104 and the first presser plate 36 there is an elastic presser device 11 8 which is composed of a helical compression spring 1 20 and a pressure sleeve 1 22. The pressure sleeve 1 22 is pointed at its right end in Fig. 3 so that it engages with its points in the concave face of the domed portion 1 04. Due to the presser device the radially outer end of the disengaging lever 46 is kept constantly in engagement with the compression nut 11 2 so that the position of the disengaging lever 46 is unambiguously determined and is not lost even if the clutch is in rotation and centrifugal forces act upon the disengaging lever 46, or if in the dismantled condition a workshop operator graps the disengaging lever 46, for example to lift the clutch.

Now the formation of the disengaging levers 48 of the second group of disengaging levers is to be considered, for which purpose reference is made to Fig. 4. The mounting 52 of the disengaging levers 48 corresponds to the mounting 50 of the disengaging levers 46. This is indicated by the insertion of corresponding references, each provided with an apostrophe.

After this short remark on the mounting 52 of the disengaging levers 48 the connection between the disengaging levers 48 and the second presser plate 38 can be discussed below. In Fig. 4 it is seen that the thrust bolts 64 are screwed with a threading 126 into a threaded bore 1 28 of a neck piece 1 30 of the disengaging lever 48. The thrust bolt 64 engages with a thrust bolt head 1 31 on a dog 1 32 of the second presser plate 38. To secure the thrust bolt 64 against rotation a compression nut 1 34 is provided having a compressible neck 1 36. The compressible neck can be pressed against a flattened portion 1 38 of the thrust bolt 64.Between the compression nut 1 34 and the disengaging lever 48 there are clamped the securing element 102' for the bearing bolts 94' and a spring arch 140. The spring arch 140 rests with its end remote from the disengaging lever on a circumferential surface 1 42 of the second presser plate 38 and thus seeks to pivot the disengaging lever 48 in the clockwise direction, considered in Fig. 4, about its pivot bearing 52 so that it abuts under spring pressure with the thrust bolt head 131 against the dog 132. The disengaging lever 48 is thus secured in a rest position.Opposite to the thrust bolt head 131 there is a pocket 144 on the housing cover plate 1 8. When the disengaging lever 48 is pivoted too far in the clockwise direction in Fig. 4, for example due to the fact that a workshop operator seeks to lift the clutch by grasping the disengaging levers, the thrust bolt head 131 comes to abut in the pocket 144, so that the disengaging lever arrangement cannot be damaged.

The clutch discs 20 and 22 are provided with friction linings 1 48 of porcelain which can be riveted directly on to the clutch discs 20 and 22, as illustrated in Fig. 4, but can also be accommodated by holders 1 50 which in turn are riveted on to the clutch discs.

The spring arrangement 40 arranged between the presser plates 36 and 38 is formed, as may be seen from Figs. 3 to 5, by a diaphragm spring. This diaphragm spring is represented in detail in Fig. 6. It comprises radially inwardly directed tongues 1 52 which abut on a rib 1 54 of the presser plate 36.

Humps 1 56 are formed on the tongues 1 52 and abut with their convex side on the annular rib 1 54. On the radially outer edge of the diaphragm spring 40 an elevation 1 58 of toroid form is formed which abuts with its convex side on an annular rib 1 60 of the presser plate. The arrangement of the convex humps 1 56 and of the convex rib 1 58 on the diaphragm spring 40 permits of dispensing with especially fine machining of the ribs 154, 166 of the presser plates 36, 38, or even any machining at all.

In Fig. 5 the diaphragm spring 40 is secured on the presser plate 36 by at least two splined pins 1 62 which on the one hand are inserted into a bore 1 64 of the presser plate 36 and on the other hand engage in the interspace between two successive tongues 1 52 of the presser plate 40.

In the modification according to Fig. 7 the centring of the diaphragm spring 40 is constituted by at least two clipped-out portions 1 66 which engage in the bores 1 64. The clippedout portions 1 66 can be formed from the material between two successive spring tongues 1 52.

Claims

1. Clutch arrangement for installation between a drive disc and a gearing, comprising a clutch housing for securing to a drive disc, at least one clutch disc within this clutch housing and connectable with a drive-output shaft leading to the gearing, at least one presser plate within the clutch housing, at least one spring arrangement for pressing the presser plate against the clutch disc and for pressing the clutch disc against a drive face arranged fast in rotation of the clutch housing or the drive disc, and disengaging levers pivotably mounted on the clutch housing with operative faces for a disengaging bearing and with engagement parts for engagement with the presser plate, characterised in that the operative faces (82) of the disengaging levers (46) are formed on operative parts (54) of porcelain, ceramics or sintered material, which operative parts (54) are secured on the disengaging levers (46).

2. Clutch arrangement according to Claim 1, characterised in that the disengaging levers (46) are produced by stamping, pressing and/ or drawing from sheet metal.

3. Clutch arrangement according to one of Claims 1 and 2, characterised in that the operative parts (54) are held by leaf springs (76) on abutment faces (74) of the disengaging levers (46).

4. Clutch arrangement according to Claim 3, characterised in that the leaf springs (76) engage in slots (80) of the operative parts (54) which are let from the respective operative face (82) into the operative body (54).

5. Clutch arrangement, especially according to one of Claims 1 to 4, characterised in that the operative parts (54) are movably arranged on the disengaging levers (46) in such a way that by their mobility they compensate for defects of alignment and/or angle between the clutch axis and the disengager axis.

6. Clutch arrangement according to Claim 5, characterised in that the disengager parts (54) are tiltable in abutment sockets (68) of the disengaging levers (46) about axes (70) placed tangentially of the rotation axis of the drive disc.

7. Clutch arrangement, especially according to one of Claims 1 to 6, characterised in that the clutch disc (20) is provided with friction linings (148) of porcelain, ceramics or sintered material.

8. Clutch arrangement, especially according to one of Claims 1 to 7, characterised in that the disengaging levers (46) are mounted, with flanges (88) substantially parallel to one another and to the clutch axis, between bearing ribs (100) of the clutch housing (14) which are likewise substantially parallel to one another and to the clutch axis, by two bearing bolts (94) each, each of which engages with a non-circular head (92) into a correspondingly non-circular aperture (90) of the respective flange (88) and with a cylindrical section (96) in a bore (98) of the respective bearing rib (100), the heads (92) of the two bearing bolts (94) of a disengaging lever (46) abutting on the one hand on the associated bearing ribs (100) and being secured on the other hand by a securing element (102) against axial displacement, which element is detachably secured on the respective disengaging lever (46).

9. Clutch arrangement according to Claim 8, characterised in that the securing elements (102) are secured on the disengaging levers (46) at the position of the connection of the engagement parts (62) with the disengaging levers (46), preferably using the connection means (1 12) which connect the engagement parts (62) with the disengaging levers (46).

1 0. Clutch arrangement according to one of Claims 1 to 9, characterised in that it is formed with two clutch discs (20, 22), two presser plates (36, 38) between these clutch discs (20, 22) and a spring arrangement (40) between the presser plates (36, 38), where this spring arrangement (40) presses the two presser plates (36, 38) away from one another against the two clutch discs (20, 22) and presses the two clutch discs (20, 22) each against a drive face (42) of the drive disc (12) and a drive face (44) of the clutch housing (14), and in that two groups of disengaging levers (46, 48) are provided, a first group (46) for acting upon the first presser plate (36) close to the drive disc (12) and a second group of disengaging levers (48) for acting upon the second presser plate (38) remote from the drive disc (1 2).

11. Clutch arrangement according to Claim 10, characterised in that tie bolts (62) act on the disengaging levers (46) of the first group radially outside the mounting (50) of these disengaging levers (46) and engage at the other end with the first presser plate (36).

1 2. Clutch arrangement according to Claim 11, characterised in that the tie bolts (62) are provided on the disengaging lever side with a threading (110), carry an adjusting nut (112) on this threading (110), and in that between this adjusting nut (112) and the respective disengaging lever (46) there lies an abutment plate (102) which serves at the same time as securing element for the bearing bolts (94) of the disengaging lever (46).

1 3. Clutch arrangement according to Claim 1 2, characterised in that the adjusting nut (112) is formed as compression nut with a deformable collar (114) for engagement with a non-circular surface (116) of the respective tie bolt (62).

14. Clutch arrangement according to one of Claims 1 2 and 13, characterised in that the disengaging levers (46) of the first group abut with a convex domed portion at (104) on the respective abutment plate (102).

1 5. Clutch arrangement especially according to one of Claims 1 2 to 14, characterised in that the disengaging levers (46) are pressed against the respective adjusting nut (112) by an elastic presser device (11 8) which bears on the first presser plate (36).

1 6. Clutch arrangement according to Claim 15, characterised in that the elastic presser device (118) comprises a compression spring (120) enclosing the respective tie bolt (62) and a presser sleeve (122) in series with this spring, preferably of synthetic plastics material, which abuts against the disengaging lever (46) preferably in the region of a concave curvature, complementary to the convex curvature, at (104) of the disengaging lever (46).

1 7. Clutch arrangement according to one of Claims 10 to 16, characterised in that threaded bores (128) are formed on the disengaging levers (48) of the second group and in that thrust bolts (64) are inserted into these threaded bores (128) and act on the second presser plate (38) radially within the pivot bearings (52) of these disengaging levers (48).

1 8. Clutch arrangement especially according to Claim 17, characterised in that the threaded bores (128) extend each into a neck (130) which is swarflessly formed on the respective disengaging lever (48) of the second group in the course of the production operation.

1 9. Clutch arrangement according to one of Claims 1 7 and 18, characterised in that the thrust bolts (64) abut each against a dog (132) of the second presser plate (38) which starting from a second presser plate (38) points in the axial direction to the respective disengaging lever (48).

20. Clutch arrangement especially according to Claim 19, characterised in that with the thrust bolts (64) there are associated abutment faces (144) on the clutch housing (14), against which the thrust bolts (64) can abut if the disengaging levers (48) are loaded in a direction opposite to the direction of action of the disengager (56), by centrifugal force or by grasping of the disengaging levers (48).

21. Clutch arrangement according to Claim 20, characterised in that the abutment faces (144) are formed by pockets of the clutch housing (14).

22. Clutch arrangement according to one of Claims 17 to 21, characterised in that the thrust bolts (64) are secured on the disengaging levers (48) by lock nuts (134).

23. Clutch arrangement according to Claim 22, characterised in that a securing element (102') for the bearing bolt (94') pertaining to the respective disengaging lever (48) is clamped in between each disengaging lever (48) and the respective lock nut (134).

24. Clutch arrangement especially according to one of Claims 1 7 to 23, characterised in that on the disengaging levers (48) there are fitted spring arches (140) which bear on a clutch part, especially on the second presser plate (38), and hold the disengaging levers (48) in a rest position.

25. Clutch arrangement according to Claim 24, characterised in that the spring arches (140) are clamped in between the disengaging levers (48) and the respective lock nuts (134).

26. Clutch arrangement according to one of Claims 10 to 25, characterised in that the spring arrangement (40) between the two presser plates (36, 38) is formed by a diaphragm spring or dished spring.

27. Clutch arrangement especially according to Claim 26, characterised in that the diaphragm or dished spring comprises convexly curved abutment humps (1 56, 1 58) for abutment on the presser plates (36, 38).

28. Clutch arrangement especially according to Claim 26 or Claim 27, characterised in that the diaphragm or dished spring is centred on at least one presser plate (36, 38) by at least two centring elements (162).

29. Clutch arrangement according to Claim 28, characterised in that the centring elements (162) are formed by axially directed splined pins which are accommodated each by a bore (164) of a presser plate (36) and engage in an aperture of the diaphragm or dished spring (40), preferably in a slot between two successive tongues (152).

30. Clutch arrangement according to Claim 28, characterised in that the centring elements are formed by angled clipped-out portions (1 66), preferably between two successive tongues (152) of the diaphragm or dished spring, which engage in bores (164) of the presser plate (36).

31. Clutch arrangement according to one of Claims 10 to 30, characterised in that it is formed as double-action clutch in that both clutch discs (20, 22) are securable on a common gearing input shaft leading to the gearing.

32. Clutch arrangement according to one of Claims 10 to 30, characterised in that it is formed as dual clutch in that each clutch disc (20, 22) is connectable with a different driveoutput shaft (24, 28).

33. Clutch arrangement for installation between a drive disc and a gearing substantially as described herein with reference to the accompanying drawings.