GB2150652A

GB2150652A - Friction disc clutch

Info

Publication number: GB2150652A
Application number: GB08426978A
Authority: GB
Inventors: Dieter Lutz
Original assignee: Sachs Systemtechnik GmbH
Current assignee: Sachs Systemtechnik GmbH
Priority date: 1983-12-01
Filing date: 1984-10-25
Publication date: 1985-07-03
Also published as: DE3343506A1; GB8426978D0; DE3343506C2; FR2560312B1; FR2560312A1; GB2150652B

Abstract

The fly-wheel (1) of the motor vehicle friction disc clutch, the clutch disc (17), the presser plate (13) and the clutch cover (11) are connected with one another into a construction unit which preferably cannot be separated without destruction. The construction unit is removably screwed to a securing disc (3), preferably formed as sheet metal shaped part, which in turn is detachably secured to the crank- shaft (9) of the motor vehicle internal combustion engine. The securing disc is radially ribbed or provided with corrugations (49) which stiffen it axially and in the circumferential direction and provide radial cooling air passages. The clutch cover (11) is clamped under radial pressure on to the fly- wheel (1), preferably consisting of cast iron, and non-detachably secured to the fly-wheel by rolling- in (39). By adjustment of the application pressure in the rolling-in it is possible to compensate for manufacturing tolerances which influence the initial stress force of the diaphragm spring (25). <IMAGE>

Description

SPECIFICATION Friction disc clutch The invention relates to a friction disc clutch, especially for a motor vehicle, comprising a first friction plate drivable about a rotation axis, a second friction plate guided fast in rotation but axially displaceably on the first friction plate, a clutch disc coaxially arranged axially between the friction plates and rotatable in relation to the friction plates, a spring device which axially resiliently initially stresses the second friction plate towards the first friction plate, and a releaser device.

In clutches of this kind the first friction plate, which forms a fly-wheel, is screwed directly to the crank-shaft of the internal combustion engine. The second friction plate, serving as presser plate, together with a clutch cover and a dished spring or diaphragm spring, forms a pressure plate unit which in assembly is screwed to the fly-wheel, being centred in relation to the crank-shaft. In this operation the initial stress force of the spring has to be overcome. The clutch disc is also to be installed as a component separate from the pressure plate unit.

Since the clutch is assembled from mutually independently assembled parts, relatively great total tolerances can result, leading to flucutations of the pressure application force from clutch to clutch. In this way undesiredly high pressure application forces can initially result, or the initial stress force reduces to unacceptably low values when the clutch is only slightly worn.

It is the problem of the invention to indicate a way in which the assembling of the clutch can be facilitated and assembly-required tolerances can be observed better.

In accordance with the invention this problem is solved in that the two friction plates, the clutch disc and the spring device are united into one construction unit which is securable, for removal as such, on a securing part coaxial with the friction plates. In such a clutch all components which influence the spring tolerances are pre-fitted into one construction unit which can be tested for tolerances and adjusted if necessary, independently of the final fitting. Such a construction unit can be balanced as a whole, which is also not possible in clutches hitherto. In the final fitting of the clutch unit no initial spring stress forces have to be overcome, and this facilitates the centring and installation. Dismantlement of the clutch is also facilitated, especially in the case of drawn clutches.If a pushin gear input shaft is present, with suitable configuration of the gear bell the clutch can be dismantled without separation of engine and gearing. The space requirement for the storage of such clutches is reduced, since the clutch disc is not stored separately but already installed in the clutch.

The first friction plate does not necessarily have already to contain the entire fly-wheel mass, even though this is preferred. A part of the fly-wheel mass can also be provided by the securing part. However the weight of the clutch can be reduced, for an intertia moment of predetermined magnitude, if the first friction plate is formed as an annular fly-wheel which is screwed to a comparatively light securing disc for connection with the crankshaft. The securing disc can be a sheet metal shaped part which is stiffened both axially and in the circumferential direction by corrugations in order to be able to take up the torque of the clutch and the axial release forces.

The sheet metal shaped part preferably extends over substantially the whole radial width of the annular fly-wheel, and is screwed to the fly-wheel in the region of its outer circumference. In this way the greatest part of the inertia masses can be placed at the outer edge of the fly-wheel, with sufficient rigidity of the fly-wheel.

The corrugations or ribs extend substantially radially between the securing disc and the axially adjacent friction plate and form cooling air passages for the friction faces of the flywheel. The wear ratios of the fly-wheel and of the presser plate can thus be of approximately equal magnitudes, in contrast to conventional clutches.

The first friction plate, which forms the flywheel, especially when stiffened by the securing disc, can consist of a cheap material, for example cast iron. In order to be able to take up the centrifugal force loading, especially in these forms of embodiment, the first friction plate is seated under initial radial pressure stress in a ring of steel or the like drawn on to the external circumference of the first friction plate, which ring can at the same time form the clutch cover. The ring forming the clutch cover is preferably secured non-detachably by crimping-over on the fly-wheel. This style of securing reduces the production costs, the clutch weight and the clutch volume.The rolling of the ring on the side of the fly-wheel remote from the presser plate is especially advantageous, since here the spring stress of the clutch spring can be adjusted by adjustment of the crimping-over force.

Examples of embodiment are to be explained in greater detail below by reference to drawings, wherein: Figure 1 shows an axial longitudinal section through the upper half of a motor vehicle drawn-type friction disc clutch; Figure 2 shows a radial detail view of the clutch according to Fig. 1, seen in the direction II, and Figure 3 shows an axial longitudinal section through the upper half of a motor vehicle pressed-type friction disc clutch.

The motor vehicle drawn-type friction disc clutch as represented in Figs. 1 and 2 comprises a fly-wheel 1 which is fixed coaxially by means of an annular sheet-metal disc 3 on a flange 5 of a crank-shaft 9, rotating about a rotation axis 7, of an internal combustion engine. The fly-wheel 1 carries a substantially annular clutch cover 11 which encloses a substantially annular-disc-shaped presser plate 1 3 on the side of the fly-wheel 1 axially remote from the crank-shaft 9. The presser plate 1 3 is guided fast in rotation but axially displaceably on the clutch cover 11 with the aid of several tangential straps 1 5 arranged in distribution in the circumferential direction.A clutch disc 17, which is coupled in the usual way axially displaceably but fast in rotation with input shaft 1 9 of a gearing (not shown further), is arranged axially between the flywheel 1 and the presser plate 1 3 coaxially with the rotation axis 7. The clutch disc 1 7 carries friction linings 2 and can comprise torsional vibration dampers indicated at 23 and frictional vibration dampers which are not further illustrated. Between the clutch cover 11 for the one part and the presser plate 1 3 for the other there is stressed a diaphragm spring 25 which resiliently initially stresses the presser plate 13, through the friction linings 21 of the clutch disc 1 7, against the fly-wheel 1.The diaphragm spring 25 is here supported in the region of its external circumference on the clutch cover 11 and lies along a diameter between the external diameter and the internal diameter on projections 27 of the presser plate 1 3. By means of a releaser rolling bearing 31, guided axially displaceably on a guide tube 29 of the gearing and acting on the radially inner ends of the tongues 35 of the diaphragm spring 25, the presser plate 1 3 can be relieved of the pressure application force of the diaphragm spring 25 and the clutch can be disengaged.

The fly-wheel 1 consists of cast iron, but can also consist of conventional fly-wheel materials, for example of steel.

The clutch cover 11 grasps non-detachably around a radially protruding annular flange 37 of the fly-wheel 1. It is seated with radial initial stress with press fit on the external circumference of the annular flange 37 and takes up the centrifugal forces acting upon the cast iron material of the fly-wheel. The marginal portion of the clutch cover 11 axially remote from the diaphragm spring 25 is rolled in behind the face of the fly-wheel 1 on the crank-shaft side and forms a radially inwardly extending annular flange 39 which holds the clutch cover 11 on the fly-wheel 1.The rollingin of the marginal portion of the clutch cover 11 at the same time clamps the clutch cover 11 radially firmly on to the fly-wheel 1.In the opposite axial direction a shoulder 41 pointing axially to the annular flange 39 fixes the clutch cover 11 on the fly-wheel 1. On the outer side of the channel formed by the shoulder 41 there is seated a toothed ring 43 for the engagement of the starter pinion.

The sheet metal disc 3 is screwed by its radially inner edge with screws 45 to the flange 5 of the crank-shaft 9. The sheet metal disc 3 protrudes radially inwards over the internal circumference of the fly-wheel 1 of substantially annular disc form and extends radially outwards substantially to the external circumference of the fly-wheel 1, where it is screwed with screws 47 through the annular flange 39 to the fly-wheel 1. Into the sheet metal disc 3 there are pressed substantially radially extending ribs or corrugations 49 which stiffen the sheet metal disc both axially and in the circumferential direction. The corrugations extending between the sheet metal disc 3 and the fly-wheel 1 form cooling air passages open radially on both sides of the fly-wheel for the cooling of the fly-wheel 1.

Between cooling air passages succeeding one another in the circumferential direction the flywheel 1 can be supported over its whole radial width on the sheet metal disc 3.

The fly-wheel 1, the presser plate 1 3, the clutch disc 1 7 and the diaphragm spring 25 form one unit which can be secured as such, by means of the screws 47, detachably to the sheet metal disc 3 and thus to the crank-shaft 9. Such a construction unit can be fitted more easily than conventional clutches, where the pressure plate unit must be secured to the flywheel against the force of the diaphragm spring. Additional centring pegs or the like to facilitate centring may be provided.Furthermore the clutch can be balanced as a construction unit and by variation of the application pressure in the rolling-on of the annular flange 39 it is possible to compensate for tolerances of the fly-wheel 1, the clutch disc 17, the presser plate 1 3 and of the clutch cover, which influence the initial stress force of the diaphragm spring 25.

Fig. 3 shows a motor vehicle pressed-type friction disc clutch which differs from the clutch according to Figs. 1 and 2 essentially only in the arrangement of its tangential straps, which guide the presser plate on the fly-wheel, and the supporting, which differs according to the type of actuation, of the diaphragm spring on the clutch cover, the presser plate and the release rolling bearing.

Parts having the same effect are designated with reference numerals increased by the number 100 compared with Figs. 1 and 2.

For more detailed explanation to this extent reference is made to the description of Figs. 1 and 2.

In detail, the noses 1 27 of the presser plate 11 3 are arranged on its external circumference and are supported on the diaphragm spring 1 25 in the region of its external cir cumference. The clutch cover 111 engages, on the side axially remote from the presser plate 11 3, into a middle region of the dia phragm spring 125, which is supported in this region on the clutch cover 111. The presser plate 11 3 is relieved of the initial stress force of the diaphragm spring 1 25 by a disengaging movement of the releaser rolling bearing 1 31 directed towards the crank-shaft 109. The tangential straps 115 are secured with their one end to the presser plate 113, with their other end however directly, that is not through the cover 111, to the fly-wheel 101. This style of fastening facilitates the assembly of the clutch and may also be used in the case of the drawn-type clutch according to Fig. 1.

Claims

1. Friction disc clutch, especially for a motor vehicle, comprising a) a first friction plate (1; 101) drivable about a rotation axis (7; 107), b) a second friction plate (13; 11 3) guided fast in rotation but axially displaceably on the first friction plate (1; 101), c) a clutch disc (17; 11 7) coaxially arranged axially between the friction plates (1, 13; 101, 113) and rotatable in relation to the friction plates, d) a spring device (25; 125) initially stressing the second friction plate (13; 113) axially resiliently towards the first friction plate (1; 101) and e) a releaser device (31; 131), characterised in that the two friction plates (1, 13; 101, 113), the clutch disc (17; 117) and the spring device (25: 125) are united into one construction unit which is securable, removably as such, on a securing part (3; 103) coaxial with the friction plates (1, 13; 113).

2. Friction disc clutch according to Claim 1, characterised in that the first friction plate is formed as an annular fly-wheel (1; 101) and the second friction plate is formed as an annular presser plate (13; 11 3) and in that the construction unit is screwed to a securing disc (3; 103).

3. Friction disc clutch according to Claim 2, characterised in that the securing disc (3; 103) is formed as a sheet metal shaped part which is stiffened both axially and in the circumferential direction by corrugations (49; 149).

4. Friction disc clutch according to Claim 3, characterised in that the sheet metal shaped part (3; 103) extends substantially over the entire radial width of the annular flywheel (1; 101) and is screwed in the region of its external circumference to the fly-wheel (1101).

5. Friction disc clutch according to Claim 3 or 4, characterised in that the corrugations (49; 149) form substantially radially extending cooling air passages axially between the securing disc (3; 103) and the axially adjacent friction plate (1; 101).

6. Friction disc clutch according to one of Claims 1 to 5, where the second friction plate (11 3) is held fast in rotation but axially displaceably on the first friction plate (101) by way of several tangential straps (115) distributed in the circumferential direction, characterised in that the ends of the tangential straps (11 5) are secured directly on the first friction plate (101) for the one part and the second friction plate (113) for the other part.

7. Friction disc clutch according to one of Claims 1 to 6, characterised in that a closed ring (11; 111) firmly encloses the external circumference of the first friction disc (1; 101) with radial press fit.

8. Friction disc clutch according to Claim 7, characterised in that the ring (11; 111) is rolled in along its edge axially remote from the second friction plate (13; 113), forming a radially inwardly extending annular flange (39; 139) engaging behind the first friction plate (1; 101).

9. Friction disc clutch according to Claim 7 or 8, characterised in that at least one of the two friction plates (1, 13; 101, 113), preferably the first friction plate (1; 101), consists of cast iron.

10. Firction disc clutch as claimed in Claim 1 substantially as described with reference to Figs. 1 and 2 or Fig. 3 of the accompanying drawings.