FR2756031A1 - DOUBLE SHOCK ABSORBER FOR MOTOR VEHICLE - Google Patents

Abstract

Double damping flywheel, for a motor vehicle, of the type comprising a primary flywheel intended to be connected to the crankshaft of the engine of the vehicle, a secondary flywheel intended to receive a clutch mechanism, circumferentially acting torsion damping means being arranged kinematically between the primary and secondary flywheels, said damping means comprising elastic means (30) with circumferential action associated with friction means, said elastic means (30) consisting of at least one group of springs (31) acting in series by the intermediate coupling parts (18) provided with rollers adapted to roll on the inner surface of an outer skirt of the primary flywheel: the coupling parts (18) carry wedging horns (29) for said springs (31) which extend, from the bearing surfaces (27), inside the springs (31).

Description

"Double damping flywheel for motor vehicle" The present invention

  has for object a double damping flywheel for

motor vehicle.

  More specifically, it relates to a double damping flywheel, for a motor vehicle, of the type comprising a primary flywheel intended to be connected to the crankshaft of the vehicle engine and a secondary flywheel intended to receive a clutch mechanism; circumferential action torsional damping means are kinematically disposed between the primary and secondary flywheels; as is known, such an arrangement allows an excellent filtering of the torsional oscillations generated by the engine, particularly in low revs, with as a consequence a

  significant reduction in noise, especially in the gearbox.

  Of course, according to this configuration, the torsion damping means have a large clearance; generally, to do this, the elastic means 1 5 are long helical springs, most often pre-bent, housed in an annular channel formed largely in the primary flywheel; taking into account the great length of the springs, it is frequent to fill said annular channel at least partially with grease and to place, between the external periphery of the springs and the interior of the annular channel, a piece of protection against wear; as can be seen, such an arrangement, of the kind described for example in document FR-A-2 601 104, is expensive. It has already been proposed, in a torsion damper, to work in series a group of springs, arranged circumferentially, by means of coupling parts provided with rollers adapted to roll on the inner surface of an outer skirt of the steering wheel. primary; this arrangement is described for example in document FR-A-2 393 200; but, here again, the arrangement is complicated, the primary and secondary members of the shock absorber, more particularly the secondary member, are provided with additional pieces in the form of blinders to wedge the springs in particular at

  against the centrifugal force to which they are subjected.

  The present invention aims to overcome these drawbacks.

  Thus, according to the invention, a double damping flywheel for a motor vehicle, of the type comprising a primary flywheel intended to be connected to the crankshaft of the vehicle engine, a secondary flywheel intended to receive a clutch mechanism, torsional damping means. with circumferential action being kinematically arranged between the primary and secondary flywheels, said damping means comprising elastic means with circumferential action associated with friction means with axial action, said elastic means being constituted by at least one group of springs acting in series by the intermediary of coupling parts provided with rollers adapted to roll on the inner surface of an external skirt of the primary flywheel, is characterized by the fact that the coupling parts carry i15 wedging horns for said springs which extend, from spans

  support, inside the springs.

  Advantageously, each coupling piece is mounted to rotate freely

  around the axis of the double steering wheel while being guided.

  Preferably, each coupling piece comprises a body on either side of which are defined two bearing surfaces for the springs, said body being hollowed out of a cavity which opens out, on the one hand, radially and, on the other hand, axially, the roller being housed in the cavity

from which it projects radially.

  Advantageously, the roller is received in a groove made in the

  inner surface of the outer skirt.

  Preferably, each coupling piece has, at its end

  internal, an ear received in a throat of the primary flywheel.

  Advantageously, each wedge horn has an arm extending along an arc of a circle centered on the axis of the double flywheel; each arm is attached to the body by a stiffening rib extending towards

  the outside from the outermost side of each arm.

  Advantageously, the springs placed at the ends of said group of springs are in support, at rest, each on a stirrup with a U-shaped section secured to the primary flywheel; the secondary flywheel supports at least one drive tab extending transversely inside said stirrup; the drive tab is provided with at least one wedge horn; the horn of

  setting of the drive leg is identical to that of the coupling piece.

  Preferably, an end of travel stop element, integral with the secondary flywheel, is adapted to cooperate, at the relative end of travel of the primary and secondary flywheels, with at least one stop spring carried by the primary flywheel. Advantageously, each group of springs comprises at least three

  springs, at least two coupling parts being provided.

  i 5 Preferably, two groups of springs are provided.

  Advantageously, the primary flywheel has a central hub and the secondary flywheel a sleeve surrounding said central hub, a means of

  bearing being disposed between the central hub and the sleeve.

  To better understand the object of the invention, we will now describe, by way of example, purely illustrative and not limiting, a method of

  realization shown in the accompanying drawings.

  In these drawings: - Figure 1 is a section of a double damping flywheel according to the invention, corresponding to the line I-I of Figure 2; - Figure 2 is a partial view of the double flywheel along line 11-11 of Figure 1; - Figure 3 is a perspective view of a coupling part of the double steering wheel according to the invention; - Figure 4 is a perspective view of a drive tab of the double flywheel according to the invention; - Figure 5 is similar to Figure 2, the primary and secondary flywheels having rotated relative to each other; - Figures 6 and 7 are similar to the lower part of Figure 1 and

  each show a variant of friction means.

  The double damping flywheel illustrated in FIGS. 1 to 4, intended to equip a motor vehicle, comprises a primary flywheel 10 and a flywheel

secondary 20.

  The primary flywheel 10, equipped with a starter ring 11, is arranged to be connected, here by screws not referenced, to the crankshaft of the engine of the motor vehicle; the primary flywheel 10 is of revolution, of C-shaped axial section, and has an external skirt 12 and a central hub 13 connected laterally by an annular flange 14. The skirt 12 and the hub 13 are of annular shape and orientation axial, while the

  flange 14 is of transverse orientation.

  1 5 The secondary flywheel 20, also of revolution, is intended to receive a clutch mechanism, not shown, and constitutes a reaction plate adapted to cooperate with a friction disc, not shown, associated with said clutch mechanism; the secondary flywheel 20 consists of a plate 21 of annular shape of transverse orientation provided at its internal periphery with a sleeve 22 extending axially in the direction of the flange 14 of the primary flywheel 10 with which it surrounds the central hub 13. The secondary flywheel 20 is thus intended to be disengageably linked in rotation to the input shaft of the gearbox via the clutch mechanism. A rolling means 15 is disposed between the central hub 13 of the primary flywheel 10 and the sleeve 22 of the secondary flywheel 20, and is retained axially between a flange 50, directed inwards, of the sleeve 22 and attached stops fixed on the front face of the hub 13, here washers

  51 regularly distributed circumferentially.

  Circumferential action torsional damping means are

  kinematically arranged between the primary 10 and secondary 20 flywheels.

  Said damping means comprise elastic means 30 with circumferential action associated with friction means 40 with axial action. The elastic means 30 are constituted by a plurality of helical springs 31, two groups of three springs according to the example shown,

  coupled in series by coupling parts 18.

  Each part 18 comprises a body 24 provided at its internal end, that is to say that which is closest to the axis of the double flywheel when mounted therein, with an ear 25 extending circumferentially from on either side of the body 24 and pierced with a hole 35 for the passage of a rivet 23 used for fixing an anti-friction pad 26 which covers at least the radially inner end of the ear 25. The body 24 of the part 18 has a cross section, that is to say perpendicular to the axis of the double flywheel, generally V-shaped; the body 24 is hollowed out internally to define a cavity 38 whose cross section is also generally V-shaped and which opens to the outside, on the one hand, radially, through a rectangular opening 32 and, on the other hand , axially by two circular openings 33 which intersect the rectangular opening 32 along a cord smaller than the diameter of the circle corresponding to

openings 33.

  On either side of the body 24 are defined two inclined faces or bearing surfaces 27, of generally radial orientation, one on each side of the body 24, for the springs 31 and from which extend two wedging horns 29 of circumferential orientation, facing the ear 25, and adapted to be introduced inside the turns of the springs 31; the horns 29, better visible in FIG. 3, include arms 66 attached to the body 24 by stiffening ribs 67 extending outward from their outermost face; the arms 66 extend in arcs of a circle centered on the axis of the double flywheel; thus, their innermost face is parallel to the inner wall of the skirt 12 and, therefore, it is certain that, under the action of the centrifugal force to which they are subjected, the springs 31, stopped by the arms 66 ,

  will not come into contact with said skirt 12.

  The two circular openings 33, which therefore embrace an arc greater than 180 degrees, define axial cylindrical bearings with which an axis 16 cooperates in rotation for a roller 17 of small diameter whose diameter is sufficiently larger than that which corresponds to the openings 33 so that, when the roller 17 is mounted on the axis 16 in the cavity 38 of the body 24 and the axis 16 is mounted by its ends in the openings 33, the roller 17 protrudes from the rectangular opening 32 end of the body 24. Advantageously, anti-friction rings 28 are interposed between the axial walls of the openings 33 and the ends

  of the axis 16 that they receive. Anyway, thanks to the provision below

  above, in particular because the openings 33 are not of closed contour, the axis 16 is of a relatively large diameter, which reduces the pressure on the bearings formed by the internal face of the openings 33. The axis 1 6 can come as close as possible to the skirt 12, which makes it possible to reduce the circumferential width of the body 24 The annular flange 14 of the primary flywheel 10 carries, on its internal face, on a radius less than that where the coupling parts are placed 18, two sections 34 of generally U-shaped cross section, fixed by their central core with screws 39 to the flange 14 and each extending circumferentially over a little less than 180 degrees; The circumferential space which separates the opposite ends of the two profiles 34 defines a housing for two helical springs 52, diametrically opposed, whose role will appear below. The springs 52 can be axially long and be located radially closest to the skirt 12 thanks to the

  configuration of the bodies 24 of the parts 18.

  Each profile 34 therefore comprises two annular orientation wings

  axial, one internal 36, the other external 37.

  The outer wing 37 has locally a transverse rim 46 directed

outwards.

  The flange 14 of the primary flywheel 10 has an axial projection on its internal face an annular bead 47 externally running along the outer wing 37 of the profiles 34 over part of its axial length so that between the free end of the bead 47 which forms facing edge 46 and said edge 46 is

defined a throat 48.

  The groove 48 receives circumferentially sliding the ear 25 of the coupling parts 18, more precisely of the anti-friction pads 26; moreover, a groove 49 formed on the inner surface of the external skirt 12 of the primary flywheel 10 receives the rollers 17. It will be appreciated that this external guide is produced over a large diameter; therefore, the roller can be small in size 1 5 and therefore compact, which also leads to a body 24 little

  angularly bulky thus making it possible to lengthen the springs 52.

  According to the example shown, each group of springs comprising three helical springs 31, there are therefore two coupling parts 18 per group

springs.

  The two springs 31 placed at the ends of each group of springs are each supported on the edges of a stirrup 41 with a U-shaped section open axially towards the plate 21 of the secondary flywheel 20 and secured to the flange 14 of the primary flywheel 10 by rivets 42 via the central core of the U; said flange 14 therefore carries two

  diametrically opposed stirrups 41.

  The tray 21 of the secondary flywheel 20 supports two diametrically opposite radial drive lugs 43 secured to the free transverse face of the tray 21 of the secondary flywheel 20 facing the flange 14 of the primary flywheel 10 by fixing means 44 such as screws, so that said legs 43 can extend axially inside

  stirrups 41, advantageously in the middle position in the axial direction.

  The radial end of the legs 43 plumb with the stirrups 41 has dimensions such, in the circumferential direction and in the radial direction, that it fits inside the stirrups 41 so that at rest, in the position which is illustrated by FIGS. 1 and 2, the end turns of the end springs 31 are supported on the edges of the stirrups 41 and not on those of the legs 43; a circumferential clearance exists between these end turns and the lateral edges 68 of inclined bearing, of radial orientation, of the body of the lugs 43 with which these end turns are intended to cooperate circumferentially: this clearance corresponds to the operation of the motor to very low

  torque, especially when the gearbox is in neutral.

  For centering and radial maintenance of said end springs 31 in operation, as described below, the tabs 43 carry on their lateral edges 68, which face said springs, horns 45 of circumferential orientation adapted to penetrate inside the turns of said springs; the horns 45 have the same constitution and the same profiles as the horns

  29 of the coupling parts 18, for the same reasons as those explained above

above about the horns 29.

  The coupling parts 18 are mounted to rotate freely, around the central hub 13 of the primary flywheel 10, by their lug 25 fitted with the anti-friction pad 26 and their roller 17; they are axially wedged by the groove 48

and by groove 49.

  In the internal dimensions of the U of each profile 34, a limit stop member 53, in the form of a circular arc, is made to move circumferentially, secured by screws 168 to the plate 21 of the secondary flywheel 20 and adapted to cooperate, by its ends, in abutment with washers or cups 54 placed between helical springs 52 and the ends of the profiles 34; this cooperation leads to the compression of the springs 52, in one direction or the other, at the end of relative angular travel

  primary 10 and secondary 20 flywheels, and dampens this limit switch.

  The friction means 40 with axial action are arranged in the usual way, acting between the primary 10 and secondary flywheels 20. The friction means 40 here comprise a web 154, mounted rotating around the hub 13, rotated by the secondary flywheel 20 thanks to two radial lugs 55 which it has, only one of which is visible in FIG. 2 and which are diametrically opposite, these two lugs 55 cooperating with the edges of a notch 56 provided in the internal wing of each abutment element 53 with a U-shaped section. On either side of the web 154 are provided friction washers 57 associated with application washers 58 integral in rotation with the hub 13 of the primary flywheel 10 by means of radial lugs 59

  which they have and which cooperate with axial grooves of the hub 13.

  1 5 The washers 57 can be mounted loose or be fixed for example by

  bonding to washers 58 or web 154.

  The assembly can be moved axially under the stress of an elastic washer 60, being placed, as known per se, between a transverse bearing surface of the hub 13 and a circlip axially wedging the means of

  bearing 15, for example a ball bearing.

  The friction means 40 can be made otherwise; thus, according to FIG. 6, the rim 50 of the sleeve 22 of the secondary flywheel 20 is extended towards the axis of the double flywheel and is provided with a notch 61 which receives an axial tab 62 of the web 154 for its rotation drive by the secondary flywheel 20, while the inner wing of the profile 34 is extended inwards by a transverse rim 63 and is provided with an opening 64 receiving transverse lugs of the application washers 58 for their driving in rotation by the flywheel primary 10; the rim 63 constitutes, when the assembly is mounted, an axial stop cooperating with the washer

  58 placed on the secondary flywheel side.

  It will be appreciated that the friction means according to FIGS. 1 or 6 take advantage of the available space existing between the primary 10 and secondary 20 flywheels, radially below the springs 52 and axially at right

of these.

  According to FIG. 7, the friction means 40 are of the conventional type, for example with a cassette placed outside the space available between the two flywheels 10, 20 and fixed on the secondary flywheel 20, such as those described in the French patent application filed on May 4, 1995 under

  the number 95 05332 and, for this reason, will not be detailed here.

  The operation of the double damping flywheel according to the invention

  follows from the description which has just been given.

  When the primary 10 and secondary 20 flywheels have a rotational movement with respect to each other, the springs 31 of the same group of springs compress in series: FIG. 5 shows such a position where said springs 31 are tablets; in this figure, the primary flywheel occupies the same position as it has in Figure 2, while the flywheel

  secondary 20 has turned, relative to the primary flywheel 10, in the anti-

  clockwise relative to the figure, at an angle of about forty degrees. The

  springs 52 limit the relative movement between the two flywheels 10, 20.

  As can be seen, thanks to the coupling parts 18, not only the springs 31, of great length, compress in series, but moreover said parts 18 provide for said springs 31 good support in the circumferential direction and good protection against centrifugal force by their wedging horns 29. It is the same with the legs 43 which provide by their lateral edges 68 a good circumferential support for the springs 31 and a

  good protection against centrifugal force by their wedge horn 45.

  Of course, as known per se, the action of the friction means accompanies that of the elastic means 30 during the travel

  relative angular of the primary 10 and secondary 20 flywheels.

  Thanks to the invention, it is possible to obtain a large clearance

  relative angle between the flywheels 10, 20 without having to lubricate the springs 31.

  In addition, thanks to the wedging horns 29, no contact will occur between the springs 31 and the internal periphery of the outer annular skirt 12, of axial orientation, of the primary flywheel 10, despite the action exerted by the force. centrifugal on the springs 31. The presence of protective part of

  spring wear is not necessary, which is economical.

  In addition, the flounces 10, 20 have a simple shape and are robust. Here, they are made of moldable material, such as cast iron, so that their manufacture

is inexpensive.

  Thanks to the coupling parts 18 and to the drive lugs 43, very thick bearing and setting surfaces are obtained for the springs.

  31; there is therefore no provision for cups for the springs.

  In addition, we take advantage of the axial space available between the two

1 5 masses.

  It will be appreciated, due to the presence of the cavities 38, that one can

  fill them with grease to lubricate the rollers 17.

Claims (15)

  1. Double damping flywheel for a motor vehicle, of the type comprising a primary flywheel (10) intended to be connected to the crankshaft of the vehicle engine, a secondary flywheel (20) intended to receive a clutch mechanism, torsional damping means with circumferential action being kinematically disposed between the primary (10) and secondary (20) flywheels, said damping means comprising elastic means (30) with circumferential action associated with friction means (40), said elastic means (30) being constituted at least one spring group (31) acting in series by means of coupling parts (18) provided with rollers (17) adapted to roll on the inner surface of an external skirt (12) of the primary flywheel (10), characterized by the fact that the coupling parts (18) carry wedging horns (29) for said springs (31) which extend, from bearing surfaces (27), inside springs (31).   2. Double damping flywheel according to claim 1, characterized in that each coupling piece (18) is mounted to rotate freely around   the axis of the double steering wheel while being guided.   3. Double damping flywheel according to claim 2, characterized in that each coupling piece (18) comprises a body (24) on either side of which are defined two bearing surfaces (27) for the springs ( 31), said body (24) being hollowed out by a cavity (38) which opens to the outside, on the one hand, radially (32) and, on the other hand, axially (33), the roller (17)   being housed in the cavity (38) from which it projects radially.   4. Double damping flywheel according to one of claims 1 to 3,   characterized in that the roller (17) is received in a groove (49)   formed on the inner surface of the outer skirt (12).   5. Double damping flywheel according to one of claims 1 to 4,   characterized in that each coupling piece (18) has, at its internal end, an ear (25) received in a groove (48) of the steering wheel primary (10).   6. Double damping flywheel according to claim 3 to 5, characterized in that each wedging horn (29) comprises an arm (66) extending in an arc of a circle centered on the axis of the double flywheel. 7. Double damping flywheel according to claim 6, characterized in that each arm (66) is attached to the body (24) by a stiffening rib (67) extending outwards from the outermost face of each arm (66).   8. Double damping flywheel according to one of claims 1 to 7,   characterized in that the springs placed at the ends of said group of springs (31) are supported, at rest, each on a stirrup (41) with a cross-section   U shape secured to the primary flywheel (10).   9. Double damping flywheel according to claim 8, characterized in that the secondary flywheel (20) supports at least one drive lug   (43) extending transversely inside said stirrup (41).   10. Double damping flywheel according to claim 9, characterized in that the drive lug (43) is provided with at least one horn. wedging (45).   11. Double damping flywheel according to claim 10, characterized in that the wedging horn (45) of the drive tab (43) is   identical to that (29) of the coupling piece (18).   12. Double damping flywheel according to one of claims 1 to 11,   characterized by the fact that at least one end of travel stop element (53), integral with the secondary flywheel (20), is adapted to cooperate, at the relative end of travel of the primary (10) and secondary (20) flywheels, with at least one   stop spring (52) carried by the primary flywheel (10).   13. Double damping flywheel according to one of claims 1 to 12,   characterized in that each group of springs comprises at least three   springs (31), at least two coupling parts (18) being provided.   14. Double damping flywheel according to one of claims 1 to 13,   characterized in that two groups of springs are provided.   15. Double damping flywheel according to one of claims 1 to 14,   characterized in that the primary flywheel (10) has a central hub (13) and the secondary flywheel (20) a sleeve (22) surrounding said central hub (13), a rolling means (15) being disposed between the hub central (13) and the sleeve (22).