FR2688840A1 - DIAPHRAGM FOR CLUTCH MODULE AND ITS CLUTCH MODULE, PARTICULARLY FOR MOTOR VEHICLES. - Google Patents

Abstract

The diaphragm has a Belleville washer, and radial fingers (62) fragmented by slots (64). Openings (181, 182, 183) are provided for the passage of a screwing tool (20). The slits (64) have a buttonhole shaped portion. At least one buttonhole (65) is widened locally to create a third opening (181) allowing the passage of a tool (20) for screwing a fixing screw (2). Application: clutch module comprising such a diaphragm.

Description

The present invention relates to the diaphragms for the clutch module,

  in particular for motor vehicles, of the type comprising a periphery part, forming a Belleville washer, and a central part fragmented into radial fingers by slots, said central part being provided with openings for the passage of tools for screwing the module fixing screws.

clutch to a drive shaft.

  Such a diaphragm is described in the documents

  DE-A-30 13 298 and FR-A-2 662 767 and poses problems.

  Indeed, the openings weaken the fingers of the diaphragm and for reasons of indexation of the clutch module relative to its driving shaft, one of the fixing screws is offset from the other screws It is therefore necessary to provide a specific opening , said

  third opening, at the diaphragm.

  The implantation of this third opening must leave enough material at the level of the fingers so that they do not break. In addition, all the openings make the diaphragm fingers more flexible. This increased flexibility is detrimental because, for the same declutching stroke, the lifting of the pressure plate, which usually comprises the clutch module also provided with a clutch friction, is reduced so that the friction linings of the clutch friction may not be released in a suitable manner. In addition, it is important that the root zone of the diaphragm fingers is not of too great a circumferential length, so that these since appropriately controlling the desired deformation of the Belleville washer of the diaphragm In addition it is important that the diaphragm provides a maximum bearing surface for the clutch release bearing, in order to

reduce wear.

  The object of the present invention is to reconcile

all of these requirements.

  According to the invention, a diaphragm of the above type

  indicated in which the slots of the diaphragm have a buttonhole shape opening into the central opening of the diaphragm by a slot of small width, is characterized in that a third opening is provided at the buttonhole of the slots separating two to two fingers of the diaphragm for the passage of a tool for screwing a fixing screw, said opening affecting only one of the two adjacent radial fingers concerned and being formed in favor of said buttonhole. Thanks to this third opening, indexing of the clutch module relative to its driving shaft is made possible and a maximum of material is kept for the finger concerned because the third opening is

  formed by the buttonhole.

  Advantageously, this third opening is made at the internal periphery of the flank concerned of the

  buttonhole of the slot concerned.

  Thanks to all these provisions, the rooting zones of the diaphragm fingers can be reduced and said fingers offer a large bearing surface for the clutch release bearing. The other openings being, for some of them, also formed in favor of the buttonholes in the slots by affecting the

  two affected fingers of the diaphragm.

  According to an important characteristic of the invention, an arrangement has been sought which again makes it possible to reduce the flexibility of the fingers

diaphragm.

  Thus according to a characteristic of the invention, a diaphragm of the above-mentioned type in which its radial fingers are subdivided into two elementary radial fingers by a buttonhole, is characterized in that at least one of the buttonholes is widened locally for creation of a first opening allowing the

  passage of a tool for screwing a fixing screw.

  Thus the diaphragm fingers are widened, so that their resistance is good despite the openings, and that these are less flexible than those

of the prior art.

  Thanks to the buttonholes, the root zone of the diaphragm fingers can be reduced, while at their internal periphery, said fingers offer a

  large bearing surface for the clutch release bearing.

  According to another characteristic, at least a second opening, for the passage of a said screwing tool, is provided at the level of the slots separating the fingers of the diaphragm in pairs, said opening affecting

  the two adjacent adjacent fingers of the diaphragm.

  In addition, the buttonhole associated with the third opening has a specific shape to give good

  mechanical pivoting characteristics of said fingers.

  Thanks to these three series of openings, an ideal solution is obtained to respond to the problem posed, while having the possibility of having a large number of openings. According to another characteristic, said diaphragm being integrated in a clutch module comprising a clutch friction with at least one friction washer implanted radially below windows for accommodating elastic members and balusters crossing the plane of a web, said columns being located radially at the inner periphery of the windows, is characterized in that said clutch friction has complementary openings located radially below the windows in the free space freed by the friction washer, for communication with the openings of

diaphragm.

  Preferably, the openings are located at the

  level of the lower corners of the windows.

  Thanks to this arrangement, it is possible to retain all of the friction functions

  clutch, while minimizing its resistance.

  The assembly of the clutch module with integrated fixing screws is thus made possible, with good performance, both for the diaphragm and for the

clutch friction.

  The following description illustrates the invention

  with reference to the accompanying drawings in which: FIG. 1 is an elevation view with local cutaway showing a clutch module equipped with a diaphragm according to the invention; Figure 2 is a sectional view along line 2-2 of Figure 1; Figure 3 is a partial view along arrow 3 of Figure 2 of the clutch friction; Figure 4 is an axial view of another fixing screw with part of its associated passage in the clutch friction; Figure 5 is a partial view of the diaphragm

according to the invention.

  In the illustrated figures, it involves assembling a flywheel 1 on the crankshaft 8 of an internal combustion engine of a motor vehicle by means of a plurality of fixing screws 2 Here the flywheel 1 forms the plate of reaction of a clutch for a motor vehicle It is here unitary but of course it can

  be divided as described in document FR-A-2 662 767.

  In this case, the flywheel comprises a first mass of inertia fixed by the screws 2 to the crankshaft 8, a second mass of inertia comprising a plate forming the

  clutch reaction plate.

  The first mass has a hub centrally

  allowing the flywheel to be fixed on the crankshaft.

  As is known, a clutch comprises at least, in axial succession, the flywheel 1 or reaction plate, a clutch friction 3, a pressure plate 4, a cover 5, a diaphragm 6 All these

parts being annular in shape.

  In Figure 2 the flywheel 1 is intended to be secured to a driving shaft, here the crankshaft 8 of the

internal combustion engine.

  The clutch friction is intended to be secured in rotation to a driven shaft 7, here the input shaft of the gearbox, in a manner known per se, by means of a hub 31 with grooved internal bore for this purpose, the end of the shaft 7 being

  fluted in a complementary manner.

  The cover 5 is integral in rotation with the

  reaction plate 1 and is axially linked thereto.

  The diaphragm 6 is supported on the cover 5 and urges the pressure plate 4 towards the reaction plate 1 for axial tightening of the clutch friction 3 between the two plates 1.4 The diaphragm 6 has a frustoconical shape in the state free and has a circular continuous peripheral part forming a Belleville 61 washer and a circular central part

  fragmented into radial fingers 62 by slots 64.

  The internal end of the slots 64 opens at the internal periphery of said central part, in a

  central opening common to all fingers 62.

  Its external end opens into enlarged orifices 63, here generally of rectangular shape, implanted at the level of the internal periphery of the Belleville washer 61 (FIG. 5) The slots 64 are generally in the form of a buttonhole opening in the central opening of the diaphragm through a slit of

  narrow width as described below.

  Here the diaphragm 6 is pivotally mounted on the cover 5 and the cover 5 is in the form of a hollow plate and has at its outer periphery a radial rim fragmented into a fixing range

and a centrally open bottom 56.

  The fixing pads 55 are used for fixing the cover 5 to the reaction plate 1 by means of screws 3 here, for axially connecting the cover 6 to said plate 1 and also securing it

in rotation.

  As a variant, riveting can be carried out, as described in document FR-A-2 526 104, or a

crimping.

  Here the assembly is carried out as in document FR-A-2 585 424, by means of assembly, pivotally securing the diaphragm 6 to the cover 5 by axially applying said diaphragm 6 with an elastic clamping load constantly against a primary support 53 carried by the cover 5 Here this support consists of a stamped, alternatively it may be

of a rush.

  These assembly means comprise retaining lugs 51 or assembly coming from a single piece of the bottom 56 of the cover 1 by folding. These lugs 51 have an axial part passing through the diaphragm 6 by means of enlarged orifices 67 of that -ci, described below, and an end wing folded radially in the opposite direction to the axis of the assembly and defining with said

axial part a wedging elbow.

  A ring crown 54, here of frustoconical shape, is wedged in said elbow and is shaped to provide for the diaphragm a secondary support arranged opposite

primary support.

  As a variant, the assembly means may include balusters and rods, as in the

document FR-A-2 311 221.

  Normally the clutch is engaged, its clutch friction 3 being clamped between the plates 1,4 To disengage, it is necessary to press by pushing in the direction of the arrow F (figure 2) on the internal end of the diaphragm fingers. using a clutch release bearing shown diagrammatically at 70, with the consequence of canceling the load exerted by the diaphragm 6 on the pressure plate 4, releasing the clutch friction and disengaging the clutch in particular change gears. During the declutching operation, there is thus a lifting of the pressure plate by means of tongues 43 described below, the plate 4 being recalled by said tongues in the direction of the bottom 56

of the cover.

  Here the diaphragm is pinched between said primary 53 and secondary 54 supports at the inner periphery of its Belleville washer 61 and rests on the outer periphery of its Belleville washer 61 on a bead

  annular 41 fractional of the pressure plate.

  Of course, the clutch can be of the pulled type

  as described for example in document FR-A-2 463 874.

  The diaphragm then rests on the outer periphery of its Belleville washer on a support carried by the cover and on the inner periphery of its washer

  Belleville on the bead of the pressure plate.

  In this case, the stop comes, by pulling on the end of the diaphragm fingers, to release the force exerted normally by the diaphragm to disengage the clutch. Of course as described in document FR-A-2 550 835, the cover can be in one piece

with the diaphragm.

  The pressure plate 4 is integral in rotation with the cover 5, and therefore with the plate or flywheel 1, by being mounted axially movable relative to the latter by means of elastic tongues

  tangentials 43, here three in number.

  To do this, the plate 4 has at its outer periphery three ears 42 on which the tabs are fixed by riveting, which are also fixed by riveting at their other end to the cover, one of the fixing points being referenced at 57 in the Figure 1. Of course, this connection can be of the tenon-mortise type, with radial lugs of the pressure plate penetrating into complementary grooves

  formed in the skirt of the cover.

  Alternatively, this tenon-mortise type connection can be made between the pressure plate and a peripheral annular rim of the reaction plate as disclosed in the aforementioned document

  FR-A-2 550 835, the cover then being flat.

  As described in document US-A-4,892,177, an arrangement can be provided with two trays of

  pressure and a drive crown.

  The clutch friction 3 here comprises two coaxial parts mounted movable relative to each other against elastic means with circumferential action 36 and friction means 39 to

axial action.

  Here the first part comprises two guide washers 33 connected together by small columns 37 also serving for fixing a disc 34 attached to one of the washers 33 This disc 34 carries at its external periphery, on each of its faces, of

  friction pads 35 possibly split.

  It is these friction linings 35 which are intended to be clamped between the plates 1.4 for

  transmission of the torque from the shaft leading to the driven shaft.

  The second part of the friction 3 comprises a veil 32 interposed axially between the two guide washers 33 Here the friction is of the type described in document EP-A-0 382 616 and the veil 32 is mounted thus movable in rotation, with a clearance defined by means of engagement with clearance, with respect to the hub 31 For this, reference is made to FIG. 3 of the above-mentioned document Elastic means of low stiffness are

also planned.

  Of course the web 32 can be secured to the hub 31, and the structures can be reversed, the web 32 being movable relative to the hub 31 and the guide washers secured to the hub 31, the disc 34 being

secured to the veil 32.

  The friction means 39 comprise two friction washers 131 of identical shape, as well as elastic clamping means These elastic means bear on one of the guide washers and on one of the washers 131 to urge the web 32 in the direction the other guide washer 33 and thus axially tighten the other washer 131 between said web

  32 and the relevant guide washer 33.

  Annular bearings 132, of L-shaped section, are also provided, inserted radially between the internal periphery of the guide washer concerned and the hub 31. Such a bearing is visible in FIG. 2 and includes lunules penetrating into corresponding openings. of the guide washer for

its rotational drive.

  It will be noted that the friction washer 131 is of annular shape and comprises three triangular projecting points carrying nipples each penetrating into a corresponding opening made in the guide washer These washers 131 are thus secured in

  rotation of the guide washers 33.

  The guide washers 33 extending axially on either side of the web 32, the balusters 37 extend here at the outer periphery of said washers and pass through the web through oblong openings

  38, which the latter presents at its outer periphery.

  The elastic circumferential means 36 here consist of coil springs mounted partly in the windows of the web 32 and partly in the windows of the guide washers, said windows being arranged opposite and referenced 135 at the Figure 3. Here the openings 38 alternate circumferentially with the windows 135 three in number, as the springs 36 mounted without play in said windows Of course, some of the springs 36, possibly in the form of blocks of elastomeric material, can be mounted with game in

  veil 32 windows for delayed intervention.

  The friction means 39 are therefore here located radially below windows 135 and

  springs 36 as shown in Figure 3.

  As a reminder, it will be mentioned that the flywheel 1 carries at its outer periphery a starting ring 12 suitable for being driven by the starter of the vehicle, said flywheel 1 being shaped at its internal flange periphery for mounting by confrontation with the crankshaft and at using fixing screws 2, each having a head 21 and a threaded barrel 22 passing through an associated opening 11 made in the handwheel 1 to be screwed

  in the end of the crankshaft 8 shaped for this purpose.

  The steering wheel 1 is therefore clamped between the heads 21 of the

  screw 2 and the free end of the crankshaft 8.

  The fingers 62 of the diaphragm 6 are here subdivided into two elementary radial fingers each by a buttonhole 65 as described in document FR-A-2 311 221 One of the buttonholes 66 has a special shape and

will be described below.

  The lateral flanks of the buttonholes 65 are spaced from each other. Said buttonhole 65 is elongated radially from an external end closed to an internal end disposed at a distance from the internal periphery of the fingers 62 and therefore from the central opening of the eye.

diaphragm 6.

  The external ends of the buttonholes 65 are widened to form orifices 67, of generally rectangular shape and identical to the orifices 63 (FIG. 5) The orifices 67 alternate

  circumferentially with the holes 63.

  In the example shown in Figure 1, nine retaining lugs 51 or assembly are provided and the

  diaphragm has nine radial fingers 62.

  It will be noted that the slots 64 have a shape identical to the buttonholes 65 and differ from these by the fact that the internal end of their buttonhole is open by a slot which connects it radially to the central opening of the diaphragm This

  slot is very narrow (Figure 3).

  The tabs 51 alternate circumferentially with the radial orientation tabs 52 delimiting the internal periphery of the bottom 56 of the cover 5 The tabs 52 limit the inclination of the diaphragm when the cover 5 is not mounted on the steering wheel The tabs 51

  pass through the holes 67 of the buttonholes 65.

  According to a characteristic of the invention, at least one of the buttonholes 65 is widened locally to create a first opening 183 allowing the passage of a tool for the screwing of a fixing screw 2 This opening 183 is produced here at the periphery

internal buttonhole 65.

  According to a characteristic of the invention, a second opening 182 is provided at the level of the buttonhole of the slots 64 separating the fingers 62 in pairs for the passage of a said screwing tool 20, the opening 182 affecting the two radial fingers

adjacent 62 concerned.

  Here several openings 183,182 are planned, their number depends on the applications, just like the number

tabs 51 and orifices 63.67.

  According to the invention, a third opening 181 is provided at the buttonhole of the slots 64 separating the radial fingers 62 in pairs for the passage of a said tool 20, said opening affecting only one of the two radial fingers adjacent and

  being formed in favor of said buttonhole.

  Here the first 183 and the second openings 182 are circular in shape They are distributed

  regularly on the same circumference of the assembly.

  These openings 182,183 symmetrically affect respectively the slots 64 concerned and the

65 buttonholes concerned.

  The opening 181 (here generally semicircular) is implanted on the same said circumference but is not distributed in a regular manner compared to the other openings 182,183 The opening 181 affects only

  one of the fingers 62 concerned, the other finger being intact.

  It is practiced according to the invention at the internal periphery of the flank concerned of the buttonhole

  the slot 64 concerned, like the openings 182.

  As a corollary the buttonhole 66 concerned has a tortuous shape with at its internal periphery a curved portion offset towards the other end of the finger 62 concerned (FIG. 1) This buttonhole 60 is identical at the level of its external periphery to the buttonholes 65 and therefore has an orifice 67 and a radial part which ends at its internal periphery by said curved portion. Here six openings 181,182,183 are provided for the screwing of six fixing screws 2, distributed in a similar manner to said openings, the head of the screws being in correspondence with said openings, while the

  tools 20 belong to a screwdriver.

  There is an opening 181 here, three openings

182 and two openings 183.

  The opening 181, and therefore the screw concerned, allows indexing of the flywheel 1 relative to the crankshaft 8, which is in particular necessary when a

  ignition target on the steering wheel 1 or the cover 5.

  The same diaphragm may therefore be suitable for attachment to three screws on the crankshaft 8. According to another characteristic of the invention, the clutch friction comprises, coincident with the openings 181, 182,183, passage openings respectively 81.82 , 83 These openings are axially aligned with the apertures in the diaphragm and the fixing screws, so that each screwing tool can pass through the diaphragm and the clutch friction to engage the head of the screws 2, here hollowed out at this point. effect The recess 23 has for example a hexagonal or quadratic shape and it is the same for the screwing tool

  which has a complementary shape.

  As will be understood, each opening 81, 82, 83 consists of holes, coincidentally, made in the washers 33, the web 32 and the disc 34

  (figure 2) Here we pierce through the friction 3.

  This is made possible by the conformation of the clutch friction, the openings 82, 83 being located at the internal circumferential edge of the windows 135, being of generally circular shape (FIG. 3) They are located in the free space

by washers 131.

  As can be seen in FIG. 3, two of the sets of windows 135 are assigned in the vicinity of each of the ends (or corners) of their internal circumferential edge, respectively of an opening 82 and an opening 83, while the third set of windows 135 is only affected by an opening 82 in the vicinity of one of its ends (its corners) of its edges

internal circumferentials.

  The opening 81, here of circular shape, is offset circumferentially for reasons

  indexing and therefore does not affect windows 135.

  These openings 81, 82, 83 are directed inward and are located on either side of a

  tip of friction washers 131 radially in-

  below the holes 38. With this layout, the clutch friction is intact in terms of its functions and its resistance is not unduly affected by said openings. Thanks to the invention, it is therefore possible to form, with standard parts, in advance a module comprising the flywheel 1, the clutch friction 3 pre-centered, the cover 5 fixed on the flywheel 1, the pressure plate 4 mounted on the cover 5 thanks to the tongues 43, the diaphragm 6 pivotally mounted on the cover and the fixing screws 2 mounted captively

inside the module.

  It will be noted that the openings 181, 81 allow a precentring of the friction using for example a

rod.

  Of course the screws 2 are threaded into the holes 11 before placing the linings 35 of the friction 3 on the plate 1, then fixing the unitary unit pressure plate cover 4 diaphragm 6, said assembly

  being commonly referred to as the clutch mechanism.

  Once the clutch module has been mounted, the head of the screws is trapped axially between the flywheel 1 and the friction 3, so that there is no risk of the friction escaping, the length of the barrels 22 being greater than 1 steering wheel thickness 1 at

  the inner periphery of it.

  The length of the barrels 22 is such that said barrels remain in engagement with the openings there when the

  head of the screws 21 abuts between the friction 3.

  Of course, the passages 81 to 83-181 to 183 have a size smaller than the head of the screws, the size of said openings being dimensioned to allow passage of the screwing tools 20 and is therefore a function of the

hollow 23 of the head of the screws 21.

  Thus the clutch manufacturer can balance the clutch module in advance, so that the installation of such a module at the end of the crankshaft at the motor vehicle manufacturer is advantageously minimized, the operations to be carried out at said manufacturer are advantageously reduced

especially.

  No error can occur on the choice of fixing screws which do not have to be stored by

said builder.

  As will be understood, the shape of the slots 64, for the most part in the form of a buttonhole open internally for a slot of small width, makes it possible to offer the stop 70 a maximum bearing range in

  cooperation with buttonholes 65,66.

  The buttonhole of the slot 64 associated with the opening 181 participates in the formation of said opening and therefore allows a saving of material for the

  fingers 62 affected by opening 181.

  Thanks to the orifices 63,67 the rooting zone of the fingers 62, split into two elementary fingers by the buttonholes 65,66, does not have a significant circumferential development, hence an easy operation of the diaphragm The fingers 62 also have the desired resistance They allow minimization

  loss of lifting of the pressure plate.

  Of course the buttonhole 66 can have another shape, for example being devoid of a curved part at its internal periphery, the buttonhole being

  then shorter radially than the others.

  Likewise, the orifices 63 may have a different configuration from the orifices 67 by being

lower example.

  Likewise, the friction washer 131 can be

  linked in rotation to the hub web 132.

  While in the illustrated figures, said washer 131 is made of plastic, it can be metallic and include tabs in the form of a square to penetrate into the associated openings of said guide washers or of the web, said washer bearing

then a friction lining.

  In all cases, it is important that the balusters are not located at the internal periphery of the windows of the clutch friction, for reasons of resistance in particular, while the openings for the passage of the screwing tools are located radially below. windows and radially above the

  friction washer proper.

  Of course (FIG. 4), the head 121 of the screw 2 can be stepped with an end portion, of hexagonal shape, partially penetrating into the passages 81, 82, 83 of the friction. Thus the screws may not

protrude from the module before mounting.

  The balusters 37 can extend beyond the

  veil 32 and cross the plane of veil 32.

  The module may include a divided steering wheel as in document FR-A-2 662 767 or may have the constitution of that described in the document

DE-A-30 13 298.

  Finally, as a variant, the buttonholes 65, at their internal end, can be opened by a narrow slot connecting each buttonhole to the central opening of the diaphragm, so that the buttonholes 65 are identical to the slots. A diaphragm is therefore obtained.

at eighteen fingers.

Claims (8)

  1) Diaphragm for a clutch module, in particular for motor vehicles, of the type comprising a peripheral part (61), forming a Belleville washer, and a central part fragmented into radial fingers (62) by slots (64), said central part being provided with openings (181,182,183) for the passage each of a screwing tool (20) of fixing screws (2) of the clutch module to a driving shaft (8), in which the slots (64) of the diaphragm have a buttonhole shape opening in the central opening, which the diaphragm has through a narrow slot, characterized in that a third opening (181) is provided at the buttonhole of the slots (64) separating two to two the diaphragm fingers for the passage of a tool (20) for the screwing of a fixing screw (2), said opening (181) affecting only one of the two adjacent radial fingers concerned and being formed in party to favor of said buttonhole.   2) Diaphragm according to claim 1, characterized in that the third opening (181) is made at the internal periphery of the flank concerned of the   buttonhole of the slot (64) concerned.   3) diaphragm according to claim 1 or 2, wherein the radial fingers (62) are subdivided into two elementary radial fingers by a buttonhole (65), characterized in that at least one of the buttonholes (65) is locally enlarged for creation a first opening (183) allowing the passage of a tool (20)   for screwing in a fixing screw (2).   4) Diaphragm according to claim 3, characterized in that a second opening (182) is provided at the slots (64) separating the fingers (62) in pairs for the passage of a said screwing tool (20) , said opening (182) affecting the two fingers adjacent radials (62) concerned.   ) Diaphragm according to any one of   Claims 2 to 4, characterized in that the slots   (64) have a shape identical to the buttonholes (65) and differ from them by the fact that their internal end is opened by a very narrow slot, which connects the buttonhole of the slot (64) to the opening central diaphragm, and in that the first (183) and the second opening (182) extend symmetrically   on either side of their affected buttonhole.   6) A diaphragm according to claim 5, characterized in that said first (183) and said second (182) openings are made at the periphery   internal buttonhole.   7) A diaphragm according to any one of claims 4 to 6, characterized in that the first, the second and the third opening are located on the same circumference, the third opening (181) not being distributed evenly with respect to to the other openings (182,183).   8) Diaphragm according to any one of   claims 3 to 7, characterized in that the   buttonhole (66) associated with the third opening (181) ends at its internal periphery by a curved portion   shifted to the other end of the affected finger.   9) Clutch module comprising a clutch friction provided with passage openings (81, 82, 83) for tools for screwing a fixing screw, characterized in that it comprises a diaphragm according to   any one of claims 1 to 8, and in that   the openings (181,182,183) of said diaphragm are aligned with the passage openings (81,82,83) of said clutch friction.   ) A clutch module according to claim 9, in which the clutch friction includes   friction washers (131) located radially in   undersides of windows (135) for housing circumferential elastic members (36) and balusters (37) connecting two guide washers (33) arranged on either side of the web, characterized in that the balusters (37) are located radially beyond the friction washers (131), and in that said passage openings (81, 82, 83) of the clutch friction are located radially below the windows (135) in   the space freed by the friction washers (131).