FR2675872A1 - Double damping flywheel with double damping using friction, particularly for motor vehicles - Google Patents

Abstract

The double torsion-damping flywheel includes a primary mass (1), a secondary mass (10), an intermediate mass (40) coaxial with the primary mass (1), being mounted so that it can rotate with respect to the latter and to the secondary mass (10), a first series of elastic members (51) coming into play between the primary (1) and intermediate (40) masses, and a second series of elastic members (61) coming into play between the secondary (10) and intermediate (40) masses. The first friction means (40), elastically preloaded, come into play between the primary mass (1) and the intermediate mass (40), with implementation of first means (72) for meshing, with clearance, second friction means (80), elastically preloaded, come into play between the secondary mass (10) and the primary mass (1) with implementation of second means (82) for meshing, with clearance. Application to motor vehicles.

Description

 The present invention relates to a double damping flywheel, in particular for motor vehicles, comprising a primary mass comprising a hub, a secondary mass mounted on said hub, by means of a bearing, and comprising a secondary flywheel for action of a disc. friction, an intermediate mass coaxial with the primary mass being rotatably mounted with respect to the latter and to the secondary mass, a first series of elastic members with circumferential action intervening between the primary and intermediate masses, and a second series of 'elastic members with circumferential action located on a circumference of diameter less than that of said first series of elastic members and intervening between the intermediate and secondary masses.

Such a double flywheel is described in the request.
FR 90 03823 filed March 26, 1990 and not published to date. In this document, there is a viscous damping arrangement, and the intermediate mass arrangement allows the viscous arrangement to have its effects, satisfactorily when the motor vehicle engine is stopped and starting, while not interfering not running, the angular movement between the primary and secondary masses.

 In certain applications, it may be advantageous to replace the viscous arrangement by a less costly elastic clamping friction, while benefiting from the advantages of a non-annoying intervention in operation.

 The object of the present invention is to meet this wish.

 According to the invention, a double damping flywheel of the above-mentioned type is characterized in that first friction means, resiliently calibrated, intervene between the primary mass and the intermediate mass, in that first means of engagement with play are provided between said first friction means and one of said primary and intermediate masses, in that second friction means, resiliently calibrated, intervene between the secondary mass and the primary mass, and in that second engagement means clearance are provided between said second friction means and one of said primary and secondary masses.

 Thanks to the invention, when starting and stopping the engine of the internal combustion vehicle, a large angular clearance occurs between the primary mass and the secondary mass, with the intervention of the two friction means, so that a good amortization is obtained. On the other hand, when the vehicle is running, said friction means have less action, to the benefit of the comfort of the user.

 In addition, even if the first series of elastic members is blocked, it continues to benefit from correct damping by the second friction means during large movements between the primary and secondary masses, such as when starting the engine.

 According to an important characteristic, the play of the first play engagement means is less than the second play play means.

 With this arrangement, it is certain, when the vehicle is moving, that the friction will be less than when the motor vehicle is stopped and starting.

 Advantageously, said friction means are arranged in the vicinity of the hub of the primary mass, being centered by the latter, and a single elastic washer acts on the two friction devices for their calibration.

 Thanks to this arrangement, an elastic washer is saved for the benefit of the axial size and the implementation is simple.

The following description illustrates the invention with reference to the accompanying drawings in which
- Figure 1 is a partial view of the double steering wheel according to the invention and along line 1-1 of Figure 2
- Figure 2 is a half-view in axial section along the broken line 2-2 of Figure 1
- Figure 3 is a view showing on a larger scale the central part of Figure 2
- Figure 4 is a schematic diagram of the double steering wheel according to the invention.

 In the illustrated figures, the double torsion damping flywheel equips a motor vehicle, and comprises a primary mass 1 comprising a hub 6,7, a secondary mass 10 mounted on the hub 6,7 of the primary mass by means of a bearing 30 and comprising a secondary flywheel 11,12, for the action of a friction disc (not visible), an intermediate mass 40 coaxial with the primary mass 1, by being rotatably mounted relative to the latter and to the second mass, a first series of elastic members 51, with circumferential action, intervening between the primary 1 and intermediate masses 40, and a second series of elastic members 61, with circumferential action, located on a circumference of diameter less than that of said first series 51 of elastic members and intervening between the intermediate 40 and secondary 10 masses.

 According to the invention, a double damping flywheel of the above-mentioned type is characterized in that first friction means 70, resiliently calibrated, intervene between the primary mass 1 and the intermediate mass 40, in that the first meshing means clearance 72 are provided between said first friction means 70 and one of said primary 1 and intermediate 40 masses, in that second friction means 80, resiliently calibrated, intervene between secondary mass 10 and primary mass 1, and in that second clearance engagement means 82 are provided between said second friction means 80 and one of said primary 1 and secondary 10 masses.

 More specifically, the primary mass 1 comprises an annular hub 6,7 on which is attached, by non-visible screws, a hollow plate 2. At its external periphery, this plate 2 carries a starter ring 90 and has an axial return 3 at the end of which is attached, by screws 5, a counter-plate 4 of annular shape like the plate 2. The counter-plate 4 extends in the direction of the axis of the assembly, having only a radial extension limited. I1 defines, annularly with the plate 2, a cage 20 inside which extend the elastic members 51 of said first series of elastic members.

 This peripheral cage 20 is delimited externally by the annular return 3, and internally by thickeners in the form of crowns 9 in one piece respectively with the plate 2, and the counter plate 4. The cage is at least partially filled with a lubricating fluid, here grease, for the elastic members 51.

 The plate 2 and the counter-plate 4 constitute guide washers for the members 51, here of great length, and each carry for this purpose blocks 8 added by riveting thereon.

 Of course, the presence of the cage 20 is not obligatory, and the plates 2,4 may have windows for housing the members 51 capable of coming into contact, preferably with the intervention of an anti-wear coating, with the back 3.

 The secondary mass 10 comprises a secondary flywheel 11,12 and is rotatably mounted on the hub 7, here by means of a ball bearing 30, which as a variant can be replaced by an anti-friction bearing. The secondary flywheel 11,12 comprises, on the one hand, an axial return 12 at its external periphery for fixing the cover of a clutch clutch mechanism, and on the other hand, a shape reaction plate 11 annular to serve as a support for a friction lining, optionally split, of a friction disc integral in rotation with the input shaft of the gearbox; the primary mass 1 being in turn integral in rotation with the crankshaft of the internal combustion engine, its hub 6,7 and its plate 2 having for this purpose passages 52, for mounting fixing screws, not visible, to the crankshaft.

 It will be noted that said fixing screws as well as the screws for fixing the plate 2 to the hub are shown in the aforementioned document FR 90 03823 to which reference may be made.

 As in this document, the hub 6,7 is in two parts, namely a shoulder part 6 having an annular heel for centering of the plate 2 by cooperation with the internal periphery thereof, a second part 7, mounted centering on the first part 6, for mounting the bearing 30. This bearing 30 is interposed radially between the internal periphery of the plate 11, shouldered for this purpose, and the external periphery of the part 7. The external ring of this bearing 30 is wedged axially between said shoulder of the plate 11 and a washer 17 fixed to the plate 11, while its internal ring is wedged axially between a washer 16 and a shoulder 94 (FIG. 3) belonging to part 6.

 Here the washers 16 and 17 are installed at the level of the external face of the rings of the bearing 30.

Of course, the arrangement of document FR 90 03823 is conceivable, the washers then being located at the internal face, facing the plate 2, of the rings of the bearing 30.

 The secondary flywheel 11,12 is disposed in the vicinity of the backing plate 4 and has at its internal periphery a protruding overhang axially cooperating with the internal periphery of the counter plate 4 open centrally.

 An annular web 14 is fixed by screws 15 to this extra thickness and has for this purpose annularly at its internal periphery an axial return 13, into which the screws 15 of axial orientation penetrate. This veil 14 extends radially up to the level of the extra thicknesses 9.

 I1 is framed by two flanges 41, 42 belonging to the intermediate mass 40. The flange 42 is crossed at its internal periphery by the axial return 13, said flanges 41, 42 joining at their external periphery to form radial arms 43 penetrating at the interior of the cavity 20. These radial arms are fixed to each other by fixing members 44, here in the form of screws.

 Thus the flanges 41, 42 are attached to their external periphery to form the arms 43, while centrally they are offset axially with respect to each other for housing the web 14. These arms 43 are capable of interfering with play with the first series of elastic members 51 each mounted without play between the blocks 8, arranged opposite, plates 2,4.

 The flanges 41, 42 are provided, radially below the members 51 and the cavity 20, with windows 62 for housing the second series of elastic members 61 mounted without play in said windows 62, as well as in windows 63 provided, look of the windows 62, in the veil 14.

 The members 51 and 61 here consist of a plurality of coil springs with circumferential action distributed regularly, but of course, these can be replaced by blocks of elastic material, in particular as regards the springs 61.

 Here the stiffness K2 of the members 61 is greater than that of K1 of the members 61.

 It will be noted that a narrow passage exists between the flanges 41,42 and the rings 9, and that the flanges 41,42 are mounted in a floating manner, a radial clearance existing in particular between the return 13 and the flange 42 surrounding said return. Thus the flanges 41,42 constitute phasing washers, the springs 51,61 acting in series thanks to the intermediate mass 40.

 According to an important characteristic, the first friction means 70 comprise at least one first friction washer 71 centered internally by the part 6 of the hub and externally carrying teeth of trapezoidal shape circumferentially alternately with trapezoidal notches.

 As a corollary, the flange 41, the closest to the plate 2, has at its internal periphery an annular bead 45, in which are formed teeth and notches of shape complementary to those of the washer 71. The teeth of the washer 71 penetrate to clearance in the notches of the bead 45 and vice versa, for the formation of the first engagement means with clearance 72.

 The first backlash engagement means 72 are therefore carried, in part, by the washer 71, and in part by the intermediate mass 40.

 The washer 71 (Figure 3) is thickened at its internal periphery for contact with the plate 2. Similarly, the second friction means comprise at least one second friction washer 81 centered internally by the part 6 of the hub and having at its external periphery a circumferential alternation of teeth and trapezoidal notches, for clearance play with notches and complementary teeth formed at the internal periphery of the web 14, at its return 13 axially beyond the fixing screws 15. For to do this, the outer periphery of the washer 81 is offset axially relative to its internal periphery.

 The second play engagement means 82 are therefore carried, in part, by the washer 81 and, in part, by the web 14.

 Between the washers 71 and 81 is inserted a first application washer 91, while a second application washer 92 is arranged on the other face of the washer 81 in contact with the latter. These washers 91, 92 have at their internal periphery teeth for cooperation with complementary grooves 95 made at the external periphery of part 6 of the hub 11.

 Thus the washers 91 and 92 are locked in rotation on the part 6 with axial mobility.

 An elastic means with axial action 93, here in the form of a Belleville washer, is supported by its external periphery on the face of the washer 92 turned away from the washer 81, while by its internal periphery it is supported on the 'shoulder 94 also serving to wedge the inner ring of the bearing 30. Of course this washer 93 may consist of a corrugated elastic washer or the like. Thus a single elastic washer is used to calibrate the first 70 and second 80 friction means.

 It will be appreciated that the washers 91 and 92 extend radially below the return 13 and therefore that the available space left free at the outer periphery of the hub 6,7 is best occupied.

 The first washer 71 extends radially beyond the external periphery of the second washer 81, the bead 45 of the flange 41 being adapted to the thickness of said washer 71, as well as to the free space existing between the web 14 and the tray 2.

 According to an important characteristic, the play of the first play-engaging means 72 intervening between the flange 41 and the washer 71 is less than the play of the second play-engaging means 82 intervening between the web 14 and the washer 81 ( figure 1).

The device works as follows
- when starting the internal combustion engine, the double flywheel is allowed to pass through the resonance frequency and a large angular movement occurs between the plates 2,4 and the flanges 41,42.

During this movement, the play between the arms 43 and the members 51 is caught up, said members being compressed between the blocks 8 and the arms 43 and the movement passes from the flanges 41, 42 to the springs 61 and to the web 14 with the intervention of friction means 70.80, the play of the engagement means 72.82 being canceled.

 At startup, therefore, there are two friction means 70.80.

 As will be understood, the washer 71, driven by the flange 41, is allowed to rub against the plate 2 and against the washer 91, while the washer 81, driven by the web 14, is allowed to rub against washers 91 and 92.

 When the vehicle is moving, the springs 51, 61 act in series as described above and the angular movement between the primary 1 and secondary 10 masses is less, so that the second friction means 80 are advantageously put out of play by construction, the play of the play-engaging means 92 is not canceled. Thus, by construction, there is a benefit of less friction due to the first friction means 70 and equal to half of the previous friction.

 It will be appreciated, if the springs 51 come to block due to their contact with the return 3 under the action of centrifugal force, that one nevertheless benefits from damping, since the springs 61, of greater stiffness , then make their effects felt, between the web 14 and the intermediate mass 40 integral in rotation with the primary mass 1, due to the blocking of the springs 51. No more friction then appears, the play of the engagement means 82 being chosen greater than the angular movement between the primary and secondary masses when the vehicle is traveling, while the play of the engagement means 72 is canceled when said vehicle is traveling.

 Of course, the play of the meshing means 72 can be canceled only at the end during the movement between the primary mass 1 and intermediate 40, so that at the start no friction appears when the vehicle is moving. It all depends on the applications.

 As will be understood, the primary mass is coupled to the secondary mass by two torsion damping devices 50.60 with elastic members 51.61 and friction means 70.80, the devices 50.60 being mounted in series and acting between the primary 1 and intermediate mass 40 for the device 50, and between the intermediate 40 and secondary mass for the device 60.

 The washers 71, 81, freely rotatably mounted around the hub 6, constitute drawer washers driven in play, here by the intermediate and secondary mass.

 Advantageously, the friction means 70.80 are greased during assembly, for example grease reserves are provided in the washers 71, 81 in the form of through hollows or not filled with grease, as shown in dotted lines in FIG. 3.

 Thus the friction will not drop due to pollution due to the grease coming from the cage 20, the spring 93 being calibrated accordingly. Of course, when the springs 51 are not greased, such lubrication is not necessary.

 Of course, the present invention is not limited to the embodiments described. In particular, instead of using screws 5,44,15 as a fixing member, rivets can be used.

 Similarly, the two flanges 41, 42 can be linked to each other by welding at the level of the arms 43. An elastic tightening means can be associated with each friction means 70, 80.

 The game engagement means may consist of pins of one of the components cooperating with oblong openings made in the other component.

 Finally, the structures can be reversed, for example the washer 71 may have teeth internally, to mesh with play with the hub 6, said washer being allowed to rub against the flange 41, to which is attached a counter-flange serving for the support of the elastic means for tightening the washer 71.

Claims (10)

 1) Double torsional damping flywheel, in particular for motor vehicles, comprising a primary mass (1) comprising a hub (6,7), a secondary mass (10) mounted on said hub (6,7) of the primary mass (1 ) by means of a bearing (30) and comprising a secondary flywheel (11,12), for the action of a friction disc, an intermediate mass (40) coaxial with the primary mass (1), being mounted rotatable with respect to the latter and to the secondary mass (10), a first series of elastic members (51), with circumferential action, intervening between the primary (1) and intermediate (40) masses, and a second series d elastic members (61), with circumferential action, located on a circumference of diameter less than that of said first series (51) of elastic members, and intervening between the secondary (11,12) and intermediate (40) masses, characterized in that first friction means (70), resiliently tared, in prevail between the primary mass (1) and the intermediate mass (40), in that first clearance engagement means (72) are provided between said first friction means (70) and one of said primary masses (1 ) and intermediate (40), in that second friction means (80), resiliently calibrated, intervene between the secondary mass (10) and the primary mass (1), and in that second engagement means with clearance (82) are provided between said second friction means (80) and one of said primary (1) and secondary (10) masses.  2) Double flywheel according to claim 1, characterized in that the play of the second play engagement means (82) is greater than the play of the first play engagement means (72).  3) Double flywheel according to claim 1 or 2, characterized in that the first friction means (70) comprise a friction washer (71) provided at its outer periphery with teeth alternating circumferentially with notches, for partially forming the first game engagement means (72).  4) Double flywheel according to claim 3, wherein the intermediate mass (40) has two flanges (41,42) offset axially axially with respect to each other, characterized in that the first engagement means with play (72) are formed in part at the internal periphery of one of said flanges, which for this purpose has teeth alternating with notches, for cooperation at play with the notches and teeth of said washer 71.  5) Double flywheel according to claim 4, wherein the primary mass (1) comprises a plate (2) carried by the hub (6,7) of said first mass (1), characterized in that the flange (41) the closer to said plate (2) has at its internal periphery a bead (45) for forming said first intermeshing means with play (71).  6) Double flywheel according to claim 1 or 2, characterized in that the second friction means (80) comprise a friction washer (81) provided at its outer periphery with teeth alternating circumferentially with notches for partially forming the second means mesh with play (82).  7) Double flywheel according to claim 6, in which the secondary mass (10) has a web (14) fixed to said mass (10), characterized in that said web (14) has teeth alternating with its internal periphery notches, for partially forming the second play engagement means (82), and play play with notches and teeth of said friction washer (81) of the second play engagement means (82).  8) Double flywheel according to any one of claims 1 to 7, characterized in that the first (70) and the second (80) friction means comprise friction washers (71,81) centered by the hub (6, 7) of the first mass (1) and subjected to the action of elastic means bearing on a shoulder (94) formed for this purpose at the external periphery of the hub (6).  9) Double flywheel according to claim 8, characterized in that the elastic means bear on said shoulder (94) of the hub for action on an application washer (92) locked in rotation on the hub and clamping between said washer (92 ) and the plate (2) of the first mass (1) respectively of a first friction washer (81) provided at its outer periphery in part with the first interlocking means with clearance (82), a washer application (91) fixed in rotation on the hub (6) of the first mass (1) and finally a friction washer (71), belonging to the first friction means (70), and provided at its external periphery partly with the first game engagement means (72).  10) Double flywheel according to claim 8 or 9, characterized in that said friction washers (71,81) are provided with recesses for the formation of grease reserves.