FR2670853A1 - CLUTCH DISC WITH TWO-STAGE FRICTION DEVICE. - Google Patents

Abstract

This disc comprises an input element (7, 8), provided with friction linings (9), an output element (12; 31), rotating in a limited manner around an axis of rotation (6) common to the input element (7, 8; 31), provided with a means (11), a plurality of damping elements (10) coupling the output element (12) to the input element (7, 8). A friction device (14, 18, 25) placed in the area located radially between the damping springs (10) and the axis of rotation (6), has a control disk member (14) coupled with at least the one of the damping springs (10), which element is placed together with a friction ring (25), in the force path of an annular spring (18), acting axially.

Description

Clutch disc with two-stage friction device This

  The invention relates to a clutch disc for a friction clutch, comprising a roughly disc-shaped input element provided with clutch friction linings, a roughly disc-shaped output element, rotating by limited way around a common axis of rotation, relative to the element

  input, provided with a hub, several damped elements

  sors coupling elastically in rotation the output element to the input element, one or more friction devices, placed in a zone located radially between the damping elements and the axis of rotation, acting during relative rotation of the input element and the output element, at least one of which comprises a control disc element coupled with at least one of the shock-absorbing springs, which control disc element is placed together with a ring friction in the force path of a concentric annular spring at

  the axis of rotation, acting axially.

  A clutch disc of this type is known for example from the German patent application No. P 29 16 868, in which a control disc element or a sheet of

  control allows increasing friction force

  on the angle of rotation, several individual elements participate in the reduction of the friction force. The object of the present invention is to produce a stepped friction device, comprising as few as possible parts of simple construction, this friction device having to be very secure.

  and a long service life.

  This object is achieved, according to the invention, by the fact that the annular spring is placed axially between the control disc element on the one hand and the input element or the output element on the other hand and forms, with one of these elements, a metal-to-metal friction element of the friction device, by the fact that the friction ring is placed on the side of the control disc element, opposite the annular spring and has a lower coefficient of friction than metal and the fact that the annular spring has a central friction radius which is greater than the central friction radius of

the friction ring.

  Providing on the one hand the joint use of an annular spring as a friction element as well as a large central friction radius for this spring, with a coefficient of friction greater than that of a friction ring of the device friction, ensures that a sufficient friction force deviation is achieved

  large in the friction device.

  The entire device thus comprises only a minimum of parts which can be housed in a very space-saving manner in the axial direction. By varying the central friction radii and the friction coefficient of the friction ring, it is possible to vary the differences in friction force in a simple manner and

to a very large extent.

  To define the friction side or the diameter, it is advantageous to make sure that the

  ring spring engages almost without play, periphery

  only by legs in corresponding openings

  of the disc-shaped element.

  In a particularly advantageous manner, a wavy spring is proposed for this purpose. It is certainly possible to use a flat spring, but this must be fixed in rotation so that its useful friction radius is defined. In addition, without additional means, the

flat spring is subject to wear.

  The corrugated spring is advantageously provided with flat parts, in the areas which are applied against the input element or the output element in the form of a disc. By increasing the bearing surface with flat parts, it is possible maintain spring wear

  wavy, within very narrow limits, in this place.

  According to a characteristic of the invention, it is advantageous to design the corrugated spring so that it rests against the control disc element as well as against the input element or the disc-shaped output element, by flat parts It is thus possible to produce surfaces defined with respect to the two elements, surfaces which serve to produce a force of

  uniform friction and to limit wear.

  It is proposed to provide the corrugated spring, in the region of its parts applying against the input element or the output element in the form of a disc, with legs obliquely directed towards the disc-shaped element and which engage almost without play, in the

  peripheral direction, in corresponding openings

  tes As a result, the wave spring is, on the one hand, fixed in a defined manner and produces its friction force with respect to the control disc element, on the other hand, the tabs protrude from the flat parts, view of the fixed link in rotation and cannot therefore have repercussions on

the characteristics of the spring.

  There are at least two peripherals

times three flat parts.

  A preferred embodiment comprises, in this case, four flat parts facing the control disc element and four flat parts facing the input element or the disc-shaped output element, the parts of each side being offset from each other by ninety degrees and the parts of the two sides being offset from one another by forty five degrees This results in a very uniform support of the corrugated spring on

Both sides.

  In a preferred clutch disc, its lining support is advantageously guided axially and radially by a guide ring, on the hub and, on the opposite side, are placed the friction ring, the control disc element and the corrugated spring This results in a balanced distribution of the different parts between the lining support or the cover sheet on the one hand

and the hub disc on the other hand.

  In another preferred clutch disc, the control disc element, the friction ring and the corrugated spring advantageously form part of a load damper. The stepped friction device thus intervenes only after travel. the angle of rotation for the idle damper, which means that it can be optionally fitted with its own device for

a friction force.

  In another preferred clutch disc, the friction device, consisting of the friction ring, the drive disc member and the wave spring, is placed between the hub and one of the side discs, while another friction ring is provided between the hub and the other lateral disc. In this construction, the hub disc serves as an input element for the torsional oscillation damper and the two cover sheets.

  with the hub serve as an outlet.

  Various other features of the invention

  emerge from the detailed description which follows

  of embodiment of the invention are shown by way of nonlimiting examples in the appended drawings: FIG. 1 is a partial view, in axial longitudinal section, of a clutch disc with lining support and cover disc serving for 'input element; Figure 2 shows a detail of Figure 1 with a flat spring intended to produce the friction force; Figure 3 is a projection and sectional view of a wave spring of Figure 1; Figures 4 and 5 are partial axial longitudinal sectional views of clutch plates, with load damper and idle damper; Figure 6 is a projection and sectional view of a wave spring of Figure 5; Figure 7 is a partial axial longitudinal sectional view of a clutch disc in which the hub disc serves as an input element and two discs

  cover with a hub serve as an outlet.

  Figure 1 is a partial axial longitudinal sectional view of a clutch disc 1 with a hub it placed concentrically to a common axis of rotation 6 with a hub disc 12 projecting radially outwards, this hub being placed fixed in rotation, by an internal toothing, on a transmission shaft not shown On one side of the hub disc 12 is a lining support 7 which is provided with friction linings 9, in the region of its outer periphery The support of linings 7 is guided, axially and radially, in the region of its outer periphery, by a guide ring 13 roughly L-shaped, in its toric cross section, relative to the hub 11 On the other side of the hub disc 12 there is provided a cover disc 8 which, by spacing rivets 36, is connected fixed in rotation with the packing support 7 and kept apart. The spacing rivets 36 pass through, in this case, openings corresponding to the hub disc 12 On a central diameter, there are provided, in the windows of the hub disc 12 as well as the lining support 7 and the cover plate 8, damping springs 10 which are more or less compressed when the clutch disc is subjected to a torque There is thus a relative rotation between the lining support 7 and the cover disc 8 on one side as well

  between the hub 11 and the hub disc 12 on the other hand.

  In the axial space between the hub disc 12 and the cover disc 8 as well as radially inside the zone of the shock-absorbing springs 10, a two-stage friction device is provided. firstly, a control disc element 14 which is placed in the space indicated with its basic body and which can be connected with one of the damping springs 10, by lugs 15 directed radially outwards In addition, there may be provided, on the control disc element, lugs 16 axially bent which engage in corresponding openings 17 of the hub disc 12. The two elements 15 and 16 may be provided for the specific control of the control disc member 14 Between the base body of the control disc member 14 and the hub disc 12 there is provided a friction ring 25 which has a lower coefficient of friction than that of metal. 'element of di sque of control 14 and the cover disc 8 there is provided a corrugated spring 18 which, to produce a friction force, is axially prestressed and which, for the fixed connection in rotation with the cover disc 8, is provided with lugs 20 protruding; to this end, it has corresponding openings 22 As shown in FIG. 3, the wavy spring 18 is provided with a rotating base body which is applied against the cover disc 8, by several flat parts 24, distributed on the periphery, the tabs 20 projecting obliquely and radially inwards, from these flat parts 24 The corrugated spring 18 is thus applied by several flat parts 24 against the cover disc 8 and is fixedly connected in rotation with the latter, by the lugs 20 As shown in FIG. 1, the wavy spring 18 is provided with a central friction radius R which is greater than the central friction radius r of the friction ring 25 At the same time , the coefficient of friction between the control disc element 14 and the wave spring 18 is much higher because these two elements I are made of metal than the coefficient of friction between the control disc element 14 or the hub disc 12 and the year friction water 25 which can be achieved in a

plastic material.

  Thanks to the arrangement shown and the choice of materials, it is thus possible to produce, in a first angular range of rotation from the rest position of the clutch disc, a friction force which is due to a relative displacement between the lining support 7 and the control disc element 14 on the one hand and the hub disc 12 on the other hand, by interposition of the guide ring 13 and the ring of

  friction 25, this friction force being insignificant.

  In this first angular range of rotation, in fact, the control disc element 14 must be considered as being integral, in rotation, with the cover disc 8, because the control disc element must be considered as a united unit in rotation, due to the higher friction force of the wave spring 18 with the cover disc 8 After a given angle of rotation, the control disc element 14 is prevented from rotating,

  for example by its legs 7 engaging in the openings

  tures 17 and is therefore kept fixed relative to the hub disc 12 It follows that the effect of the friction ring 25 is canceled and that the friction acts between the control disc element 14 and the corrugated spring 18 The difference in friction force, during this passage, can now be controlled by the differences existing in the friction coefficient of the friction surfaces concerned and by the difference in the central friction radii r or R The components concerned are simple to manufacture and easy assembly and are especially very compact axially. 2 shows a detail of the friction device of FIG. 1 with a flat spring 39 instead of the wavy spring. Since the flat spring 39 is supported axially, by a larger diameter and a smaller diameter, it is entirely recommended fact, for the latter, to ensure a rotation lock relative to one of the two elements In this case, the rotation lock is provided as in FIG. 1, by lugs 40 which are directed radially towards the and which engage, in an almost fixed manner in rotation, in openings 22 of the cover disc 8 The flat spring 39 is applied, in this case, with all its outer edge, against the disc element 14 and serves as a friction element with respect thereto The central friction radius R of the

  flat spring 39 is here defined by its outside diameter.

  FIG. 4 shows, with reference to a partial sectional view of a clutch disc 2, the manner in which the friction device previously described can be placed in a clutch disc with integrated idle damper 30 On the hub 11, a hub disc 26 is placed, by a backlash 27, so that, in the region of the counter play, the idle damper 30 acts When this play is exceeded, the load damper

  becomes operative and the idle damper is bridged.

  The load damper comprises the cover disc 8 fixedly connected with the lining support 7, these two elements being in active connection with the hub disc 26, by damping springs 10 Between the hub disc 26 and the lining support 7, an idle damper 30 is provided, the different parts of which are in principle designed like the clutch disc of FIG. 1 and consist of two cover discs and a hub disc as well as damper springs in windows of the two groups, a separate friction device which can still be provided Between the hub disc 26 and the cover disc 8, is inserted the friction device already described, consisting of the control disc element 14 with its lugs 15 and its lugs 16, as well as the corrugated spring 18 and the friction ring The lining support 7 is guided, in this case, relative to the hub 11, by a guide ring 37 In addition, it is t provided a friction ring 28, between the lining support 7 and the components of the idle damper 30, connected in rotation with the hub disc 26 The corrugated spring corresponds to the embodiment shown in FIG. 3 and is connected , fixed in rotation, with the cover disc 8, by lugs 20, projecting, engaging in openings 22 of this disc It exerts an axial force which clamps together all the components provided with friction elements. inside the rotation play authorized by the play gear 27, only the friction device 38 for idling, acts with the friction effect of the guide ring 37 as well as the force of

  corresponding spring preload for damping

  idle speed 30 After compensation for the play in the backlash 27, the load damper intervenes and, in this case, first of all the friction forces produced by the friction rings 25 and 28, because in this operating region , the control disc element 14 is still connected with the cover disc 8, by the friction greater than that of the corrugated spring 18 After exceeding the angular range of rotation, ensuring this reduced friction, the control disc element 14 is kept fixed relative to the hub disc 26 and the friction goes to a much higher value which is conditioned by the coefficient of friction between the drive disc element 14 and the corrugated spring 18 as well as by the difference between the spokes central friction r

or R according to figure 1.

  FIG. 5 represents a clutch disc 3 which corresponds, in its action, to the clutch disc 2 of FIG. 4, but in which the idle damper 30 is located outside the components of the damper of load The clutch disc 3 corresponds, within the perimeter of its load shock absorber, roughly to the construction of the clutch disc 1 of FIG. 1, the hub there being placed, by a set of teeth 27, on a inner hub 29 which, in turn, is wedged on the drive shaft not shown The idle damper 30 is placed laterally and acts between the two hubs il and 29 The load damper comprises a corrugated spring 19 whose figure 6 represents a view in projection and in section Unlike the wavy spring 18 of FIG. 1, this comprises tabs 21 projecting obliquely radially outwards which engage in

  corresponding openings 22 of the lining support 7.

  The other components have already been described with reference to

Figure 1.

  The operating mode of this clutch disc 3 corresponds to that of the clutch disc 2 of FIG. 4 The corrugated spring 19 is however provided with flat parts 23 or 24 facing the lining support 7 as well as facing the element of the control disc 14, a well-defined support of the friction zones being thus produced relative to the control disc element 14 These flat parts 23 facing the control disc element 14 reduce the wear at this location because it is

  produces a defined contact between surfaces.

  FIG. 7 represents a clutch disc 4 in which the principle construction of the elements in

  disc shape input element and output element-

  is reversed compared to the construction of figure 1.

  The two cover discs 32 are fixedly connected with the hub 33, by rivets 35, while the hub disc 31 forms, with the friction linings 9, the input element and is guided rotating, against the force of the torsion springs 10, relative to the hub 33 and to the two cover discs 32 Radially inside the shock absorber springs 10, a friction ring 34 is provided, between the hub disc 31 and a cover disc 32 and, on the other side, there is provided the friction device consisting of the control disc element 14, the friction ring 25 and the wave spring 18 In this case, the wave spring 18 is designed like that of FIG. 3 and may comprise, in addition to the flat parts 24 on the side of the cover disc 32, flat parts 23 on the side of the control disc element. The operation corresponds to the operation already described; here again, after exceeding a given angle of rotation, the friction force is no longer produced by the friction ring 25 and it is the corrugated spring 18 which produces the friction force, which is greater, depending on the difference in the coefficient of friction and the

  difference in the central friction radius.

Claims (9)

  1 Clutch disc for a friction clutch, comprising an approximately disc-shaped input element (7, 8; 31), provided with clutch friction linings (9), an output element (12 ; 31) roughly disc-shaped, rotating in a limited fashion about a common axis of rotation (6), relative to the input element (7, 8; 31), provided with a hub ( 11; 33), several damping elements (10) coupling, in rotationally elastic manner, the output element (12; 32) to the input element (7, 8; 31), one or more friction devices (14, 18, 25; 14, 25, 39; 14, 19, 25), placed in a zone located radially between the damping elements (10) and the axis of rotation (6), acting during the relative rotation of the input element (7, 8; 31) and the output element (12; 32), at least one of which comprises a control disc element (14) coupled with at least one of the shock-absorbing springs (10), which ele The control disc is placed, together with a friction ring (25), in the force path of an annular spring (18; 19; 39) concentric with the axis of rotation (6), acting axially, characterized in that the annular spring (18; 19; 25) is placed axially between the control disc element (14) on the one hand and the the input element (7, 8) or the output element (32) on the other hand and forms, with one of these elements, a metal-to-metal friction element of the friction device (14, 18, 25; 14, 25, 39; 14, 19, 25), in that the friction ring (25) is placed on the side of the control disc element (14), opposite the annular spring (18; 19;) and has a lower coefficient of friction than that of metal and in that the annular spring (18; 19;) has a central friction radius (R) which is greater than the central friction radius (r) of the ring of friction (25).   2 clutch disc according to claim 1, characterized in that the control disc element (14) is made of metal and the annular spring (18; 19; 39) and the friction ring (25) apply directly against the drive disc element (14) on opposite sides to one another.   3 Clutch disc according to any one   claims 1 and 2, characterized in that the spring   annular (18; 19; 39) bears, on the side axially opposite the control disc element (14), against the input element (7, 8) or the output element (32) and has, on this side, tabs (20; 21; 40) which engage, almost without play, peripherally, in openings (22) of the input element (7, 8) or of the output element (32).   4 clutch disc according to claim 3, characterized in that the control disc element (14) has tabs (16) which engage peripherally with a certain play in openings (17) of the element d input (7, 8) or the output element (32) not connected with the annular spring (18; 19; 39) by its legs (20; 21; 40).   Clutch disc according to any one   claims 1 to 4, characterized in that the spring   annular is a wavy spring (18; 19) whose annular body has several planar portions (23, 24) distributed peripherally, by which the annular body is pressed against the input element (7, 8) or the element exit (32) on the one hand and / or against the element   control disc (14) on the other hand.   6 clutch disc according to claim 5, characterized in that, of a certain number, at least, of the flat parts of the annular body, of the tabs (20; 21) protrude, obliquely, towards the axis of rotation ( 6),   which legs engage, more or less, without peripheral play   only in openings (22) of the input element (7,   8) or the output element (32).   7 clutch disc according to claim 5 or 6, characterized in that there is provided, on the annular body, at least three pairs, distributed around the periphery, each consisting alternately and successively of a flat part (24 ) pressing against the input element (7, 8) or against the output element (32) and a flat part (23) applying against   the drive disc member (14).   8 clutch disc according to claim 7, characterized in that there are provided four pairs of flat parts (23, 24) which are all offset by one 45 compared to each other.   9 Clutch disc according to any one   claims 1 to 8, characterized in that the element   input comprises two lateral discs (7, 8) fixedly connected to each other, axially spaced and rotating guides on the hub (11), one of which (7) forms a support for friction linings and in that the output element comprises a hub disc, placed between the side discs (7, 8) and in that one (7) of the side discs (7, 8), in particular the lining support disc, is guided radially against the hub (11), by means of a guide ring (13) and the friction ring (25), the control disc element (14) and the axially acting spring (18) are placed axially between the disc   hub (12) and the other (8) of the two side discs.   Clutch disc according to any one   claims 1 to 8, characterized in that the element   input has a guided hub disc (31) rotating on the hub (33) and the output element has two lateral discs (32) arranged axially on either side of the hub disc (31), fixedly connected with the hub (33), in that the friction ring (25), the axially acting spring (18) and the control disc element (14) are placed axially between the hub disc (31) and the one of the side discs (32) and in that another friction ring (34) is placed between the disc of   hub (31) and the other of the two side discs (32).   11 Clutch disc according to any one   of claims 1 to 10, characterized in that it is   provided separate shock absorber systems (7, 8, 10, 12, 30) for idling and load operation, each of which has shock absorber springs and at least one friction device and in that the disc member of control (14), the friction ring (25) and the annular spring (18) are an integral part of the system   shock absorber designed for operation under load.