FR2687442A1 - Double damping flywheel, particularly for a motor vehicle - Google Patents

Abstract

The double damping flywheel includes a first mass (1) with a central hub (16), a second mass (2) comprising a plate (20) with an outer hub (29), a torsion damper coupling the first mass (1) to the plate (20), a friction device (5) acting axially between the first mass (1) and the second mass (2) and comprising a friction washer (54). The friction washer (54) is shaped at its outer periphery so as to engage with clearance with axial projections (56) secured to the outer hub (29). The said torsion damper extends radially beyond the said projections (56). The elastic means with axial action (51) of the friction means (5) bear on a shoulder (27) carried by the central hub (16). Application: motor vehicles.

Description

 The present invention relates to a double damping flywheel, in particular for a motor vehicle, of the type comprising a first mass comprising a central hub, a second mass comprising a plate internally carrying an external hub partially surrounding said central hub, a torsional damper with circumferential action coupling the first mass to the plate of the second mass and comprising a fixing part secured by means of fixing to said plate, a friction device acting axially between the first mass and the second mass and comprising a friction washer in friction contact with a friction surface integral with the first mass, in which, on the one hand, the second mass is rotatably mounted on the first mass by means of anti-friction bearings interposed radially between said central hub and said external hub and , on the other hand, said friction device surrounds the mo central eye and comprises an application washer subjected to the action of elastic means with axial action for clamping said friction washer between said application washer and said friction surface.

Such a double flywheel is described in the document
GB-A-2 160 296. In this, the torsional damper comprises a disc which extends radially inwards at the level of the external hub to provide a bearing surface for a Belleville washer belonging to the friction.

 This disc is secured by columns to the plate of the second mass. The balusters serve to drive the application washer in rotation without play.

 As a result, the friction device urges said columns, which, moreover, are of great length so that the solidity of the fixing of the torsion damper can be affected.

 This is not favorable to a deferred intervention of the friction means because then the columns should cooperate in play with the application washer, which would cause additional undesirable shocks.

In addition, the disc is extended and specially shaped to serve as a support for the washer.
Beautiful city. In addition, the friction surface cannot have as large an extent as desired, since it is interrupted locally by passages allowing the crimping of the columns, and the Belleville washer exerts a load on the plate of the second mass.

 Finally, the application washer has a large size, which increases its cost.

 The object of the present invention is to overcome these drawbacks in a simple and economical manner and therefore to create a new arrangement in which the torsional damper, with its associated fixing means, is independent of the friction means involved in play.

 According to the invention, a double flywheel of the above-mentioned type is characterized in that the friction washer is shaped at its external periphery to mesh in play with axial projections integral with the external hub and distinct from the means of fixing the shock absorber of torsion to the plate of the second mass, in that said torsion damper, with its associated fixing means, extends radially beyond said projections, and in that the elastic means with axial action of the friction means are supported on a shoulder carried by the central hub, for action on said application washer.

 Thanks to the invention, the friction means can intervene with play and the torsion damper is simplified and arranged.

 In addition, the friction surface of the first mass is not interrupted for fixing the torsional damper.

 The elastic means of the friction means do not exert a load on the plate of the second mass and can be used to load axially anti-friction bearing means with a divided internal ring, as in GB-A-2 160 296, which is favorable to a reduction in parts. In addition, the size of the application washer is reduced.

 Advantageously, the projections are in one piece with the central hub and extend in axial projection relative to said bearing means. This arrangement is very economical and robust.

 Advantageously, the friction washer is extended at its outer periphery to present notches, legs or the like, meshing with play with the projections. This arrangement is very economical, said extension advantageously forming an additional thickness, which simplifies the shape of the washer and increases the contact surfaces with the projections.

 In addition, the friction surface of the washer is increased by virtue of the extension, and the elastic means of the friction means can act centrally on the friction washer.

 According to another characteristic, the friction surface belongs to a carrying flange carrying the central hub and is offset axially relative to a main flange of the first mass.

 Thus, the external hub is of reduced axial size and the first mass may comprise a sealed housing, easily obtained by molding, and comprising in one piece the support flange, the central hub and the main flange.

 The friction washer can then close a sealed cavity at the level of the support flange.

 The torsion damper can then comprise an annular web of L-shaped section and penetrating into a cavity delimited by said housing.

Other advantages will become apparent in the light of the description which will follow with regard to the appended drawings in which
- Figure 1 is a half view in axial section of the double damping flywheel according to the invention
- Figure 2 is a partial view along arrow 2 in Figure 1, the cover and the tray having been removed
- Figure 3 is a partial view showing the interlocking play of the friction washer with the axial projections;
- Figure 4 is a partial view showing the connection by cooperation of shapes between the application washer and the central hub.

 The double damping flywheel illustrated in the figures is intended to equip a motor vehicle and is of the type comprising a first mass 1 comprising a central hub 16, a second mass 2 comprising a plate 20 internally carrying an external hub 29 partially surrounding said central hub 16, a torsional damper with circumferential action 4,41,32,31,21 coupling the first mass 1 to the plate 20 of the second mass 2 and comprising a fixing part 21 secured by fixing means 24 to said plate 20, a friction device 5 acting axially between the first mass 1 and the second mass 2 and comprising a friction washer 54 in friction contact with a friction surface 60 integral with the first mass 1.

 In this double flywheel, on the one hand, the second mass 2 is rotatably mounted on the first mass 1 by means of anti-friction bearings 3 interposed radially between said central hub and said external hub and, on the other hand , said friction device 5 surrounds the central hub 16 and includes an application washer 53 subjected to the action of elastic means with axial action 51 for clamping said friction washer between said application washer and said friction surface.

 According to the invention, a double flywheel of the above-mentioned type is characterized in that the friction washer 54 is shaped at its external periphery to mesh with play with axial projections 56 integral with the external hub 29 and distinct from the fixing means 24 from the torsional damper 4,41,32,31,21 to the plate 20 of the second mass 2, in that said torsional damper, with its associated fixing means 24, extends radially beyond said projections 56 , and in that the elastic means with axial action 51 of the friction means 5 bear on a shoulder 27 carried by the central hub 16, for action on said application washer 53.

 More precisely, the first mass 1 comprises globally annular parts, namely a hollow housing 10, 14, here metallic, with a flange 14, generally transverse and sealed, carrying at its external periphery a flange 10, of axial orientation, a cover 11 and the central hub 16. The cover 11 externally defines with the housing 10, 14 an annular cavity 15, partially filled with grease.

 To do this, the cover 11 is tightly fixed on the flange 10, here by screws 12, a seal being visible in dark in FIG. 1.

The rim 10 carries a fixing gear 13 for fixing suitable for being driven by the starter of the vehicle.

 The hub 16 is integral with the flange 14, called the main flange below, forming the bottom of the housing 10, 14. This hub 16 extends in axial projection relative to said bottom 14 and is here in one piece with the metal housing advantageously obtained by molding.

 The mass 1 is locked in rotation on the internal combustion engine of the motor vehicle by being fixed to the crankshaft of said engine by screws passing through passages 17 made in the hub 16.

 The second mass 2 is locked in rotation on the input shaft of the gearbox by means of the clutch of the motor vehicle.

To do this, mass 2 presents the plate 20 forming the clutch reaction plate. It is on this plate that is suitable for coming into friction contact with the friction disc of the clutch integral in rotation with the input shaft of the gearbox.

 For more precision, reference will be made to document GB-A-2 160 296, the friction face of the plate 20, here in cast iron, bearing the reference 22, while the fixing face of the clutch cover bears the reference 23.

 The second mass 2 further comprises an annular veil 21, here metallic in the shape of an L, coupled in rotation to the reaction plate 20 and penetrating into the cavity 15 axially between the bottom 14 and the cover 11.

This veil 21 belongs to the torsion damper, and here has an L-shaped section with a central tubular fixing part fixed to the plate 20. The cover 11 extends internally to said central part of the veil 21 by surrounding this with formation of a narrow passage. Thus, the fat of the cavity 15 does not risk escaping.

 The web 21 is provided with radial arms 31 (FIG. 2) for interference and support on elastic means with circumferential action 4 belonging to said torsion damper. Here the elastic means 4 consist of a plurality of coil springs 4 of great length resting on projecting blocks 32, facing each other, secured, for example by riveting or welding, to the cover 11 and the flange 14. These blocks 32 also belong to the torsion damper, like the arms 32, and are notched to cooperate with bases 41 serving to support the ends of the springs 4.

 Here the springs 4 are mounted without play between the blocks 32 and with play with respect to the arms 31. Of course the springs 4 can be mounted without play with respect to the arms 31 depending on the applications.

 The springs 4 extend at the internal periphery of the rim 10 and are lubricated by the grease in the cavity 15, which increases their service life.

Here the elastic means with axial action 51 of the friction device consist of a washer
Beautiful city. Alternatively, it may be a corrugated washer with axial action or two Belleville washers.

 The application washer 53, of reduced size, is linked in rotation to the central hub 16 by a link 58 with cooperation of shapes. Here the connection is of the fluted type and the hub has at its external periphery locally an additional thickness 52 with teeth of trapezoidal shape, while the application washer 53 has at its internal periphery complementary notches to cooperate with said teeth (FIG. 4).

 As a variant, it is possible to form complementary flats on the extra thickness 52 and in the internal bore of the washer 53.

 The friction washer 54 is inserted axially between the application washer 53 and the friction surface 60 of the mass 1. The friction device 5 surrounds the central hub 16 on which the anti-friction bearing means 3 are mounted, here a single row ball bearing.

 As a variant, the bearing means 3 may consist of a bearing with two rows of balls as in document GB-A-2 160 296 or a bearing made of anti-friction material.

 The bearing 3 is interposed radially between the hub 16 and the external hub 29 secured to the reaction plate 20, being here in one piece with the latter.

This hub 29, which extends at the internal periphery of the plate 20, is shouldered at the level of the face 22 for support of the external ring of the bearing engaged in the internal bore of the hub 29 and axially wedged on said hub by said shoulder and by a washer 26, such as a circlip, axially wedged internally on the hub 29 by means of a shoulder thereof (FIG. 1).

 The bearing 3 is fixed axially on the hub 16, on the one hand, by means of a washer 28 serving to support the head of the fixing screws (not visible) of the hub 16 to the crankshaft and, on the other hand part, by means of a washer 27 wedged axially on a shoulder formed by the free end of the extra thickness 52.

 The second mass 2 is thus wedged axially on the first mass 1 by being rotatably mounted relative to the latter by means of anti-friction bearings 3.

 The washer 27 forms a shoulder carried by the central hub 16 and serves as a support for the Belleville washer 51. The friction washer 54 is shaped to mesh with play with the axial projections 56 of the hub 29.

 These projections may consist of pins added to the external hub 29 but here the projections 56 are integral with the hub 29 and have a rectangular section.

 The friction washer 54 carries at its external periphery 55 here notches open externally 57 in which the protrusions 56 engage in play.

 The notches 57 may belong to a part secured to the washer 54, for example by overmolding, but here advantageously the friction washer 54 is in one piece. It is mounted to rotate freely relative to the application washer 53 and to the friction surface 60 of the first mass 1.

 Here this range 60 is continuous and belongs to a carrying flange 59 is offset axially with respect to the main flange 14 by extending radially inwards. This flange 59 belongs to an annular nose projecting from the flange 14 and directed towards the projections 56. This flange 59 carries the hub 16 centrally in one piece, while said nose extends at the internal periphery of the flange 14. The central part of the housing is therefore stepped, its flange 59 being generally in the plane of the web 21.

 The friction surface 60 is formed by the transverse face of the flange 59 facing the hub 29. It can be seen (FIG. 1) that the friction washer 54 can have the desired size without being hindered by the fastening means 24 of the web 21, said fixing means 24 here consisting of screws whose heads engage in associated blind holes 25 formed in the reaction plate 20. These screws 24 pass through the bottom of the blind hole to be screwed into the central part of the web 21. As a variant, the fixing means consist of rivets.

 We see that the web 21 extends radially beyond the hub 29 and that said outer hub 29 has, in axial projection relative to the bearing 3, an annular nose 30 carrying at its free end the projections 56. Thus the size of the web 21 can be reduced.

 Here the nose 30 has generally the same external diameter as the flange 59 and enters with the projections 56 in the housing 14,10.

 This arrangement opens the way to a large number of applications. Indeed, the friction washer 54 can be extended at its outer periphery 55 and thus have closed notches in the form of oblong holes (dotted lines in FIG. 3) for penetration with clearance of the protrusions 56. As a variant, the washer 54 can be provided at its outer periphery 55 with radial arms.

 Advantageously, the washer 54 is thickened at its outer periphery 55 in the direction of the hub 29, so that the bearing surfaces, between the projections 56 and said washer 54, are increased and the mating phenomena reduced. Furthermore, the extra thickness, in combination with the nose 30, prevents the fat from escaping from the sealed cavity 15 by forming a narrow passage between the flange 59 and the nose 30. The extra thickness internally closes the cavity 15.

 The washer 53 extends, like the washer 51, below the extra thickness 55 of the washer 54 and the projections 56.

 The washer 54 is advantageously made of plastic loaded with particles to give it the desired coefficient of friction, and is reinforced by fibers, such as glass fibers. It is easily obtained by molding.

The double shock-absorbing flywheel works as follows
- when the vehicle is initially driving the housing 10,14 and the cover 11 move angularly relative to the arms 31 driving with them the springs 4 until the bases 41 come into contact with the arms 31, the springs 4 being subsequently compressed to couple the first mass 1 to the plate 20
- during the relative movement of the mass 1 relative to the mass 2, the friction means 5 are inactive as long as the circumferential play, between the projections 56 and the notches 57, is not canceled
- After taking up the play, the friction washer is allowed to move relative to the friction surface and to the application washer by meshing with the projections 56;
- when the engine is started or stopped, the resonant frequency of the double flywheel is passed and a large angular movement occurs between the first and the second mass with the intervention of the friction device 5.

 Thus, thanks to the invention, and to the angular play between the projections 56 and the notches 57, the friction means can usefully be brought into play for a large clearance between them, so that at engine idling speed, said friction means are inhibited and that vibrations can be properly filtered.

 It will also be appreciated (FIG. 1) that the elastic washer 51 generally rests centrally, through the washer 53, on the friction washer 54, which is particularly favorable from the point of view of friction.

 Of course, the present invention is not limited to the embodiment described. In particular the web 21 of the torsion damper can be distinct from its central part then serving for the fixing of two flanges arranged on either side of the web 21. This web 21 then being clamped between the two said flanges, so that a torque limiter is formed.

 The reaction plate 20 may comprise radially beyond the nose 30 a second nose replacing the annular central part of the hub 21, said veil then being reduced to a disc fixed on this second nose.

 Finally, the shoulder 27 may be in one piece with the hub 16. It is possible, for example, to radially increase the notches of the washer 53 for mounting by force passage of the shoulder 27. The mounting of the washer 51 is also performing by force passage of the shoulder 27.

Claims (10)

 1) Double damping flywheel, in particular for a motor vehicle, of the type comprising a first mass (1) comprising a central hub (16), a second mass (2) comprising a plate (20) internally carrying an external hub (29) surrounding in part said central hub (16), a torsional damper with circumferential action (4,41,32,31,21) coupling the first mass (1) to the plate (20) of the second mass (2) and comprising a part of fixing (21) secured by fixing means (24) to said plate (20), a friction device (5) acting axially between the first mass (1) and the second mass (2) and comprising a friction washer (54 ) in frictional contact with a friction surface (60) integral with the first mass (1), in which, on the one hand, the second mass (2) is rotatably mounted on the first mass (1) via anti-friction bearing means (3) interposed radially between said central hub and ledi t external hub and, on the other hand, said friction device (5) surrounds the central hub (16) and comprises an application washer (53) subjected to the action of elastic means with axial action (51) for tightening of said friction washer between said application washer and said friction surface, characterized in that the friction washer (54) is shaped at its external periphery to mesh with play with axial projections (56) integral with the external hub ( 29) and distinct from the means for fixing (24) the torsional damper (4,41,32,31,21) to the plate (20) of the second mass (2), in that said torsional damper, with its associated fixing means (24), extends radially beyond said projections (56), and in that the elastic means with axial action (51) of the friction means (5) bear on a shoulder (27) carried by the central hub (16), for action on said application washer (53).  2) Double flywheel according to claim 1, characterized in that said projections (56) are in one piece with the external hub (29) and extend projecting relative to the means of anti-friction bearings (3).  3) Double flywheel according to claim 2, characterized in that the projections (56) belong to an annular projecting nose (30) in one piece with the plate (20) of the second mass (2), and in that said torsion damper (4,41,31,32,21) is fixed on said plate (20) radially beyond said nose (30).  4) Double flywheel according to any one of claims 1 to 3, characterized in that the friction washer (54) is notched at its outer periphery (55) to cooperate after taking up a clearance with the projections (56) of the external hub (29).  5) Double flywheel according to claim 4, characterized in that said notches (57) are formed by means of an extra thickness, which has the friction washer (54) at its outer periphery (55), said extra thickness being directed towards the outer hub (29).  6) Double flywheel according to any one of the preceding claims, characterized in that the application washer (53) of the friction means (5) is linked in rotation by cooperation of shapes to the central hub (16).  7) Double flywheel according to claim 6, characterized in that, for formation of said connection by cooperation of shapes, the central hub (16) locally has an extra thickness (52) delimiting at its free end a shoulder.  8) Double flywheel according to claim 7, characterized in that said free end of the extra thickness (52) serves as a support shoulder for a washer (27) axially wedging said means of anti-friction bearings (3) and serving as 'support to the axial action elastic means (51) of the friction means (5).  9) Double flywheel according to any one of the preceding claims, in which the first mass (1) comprises at its external periphery a main flange (14), characterized in that the friction surface (60) belongs to a flange (59 ) axially offset, toward the external hub (29), relative to the main flange (14) of the mass (1), and in that said flange (59) is integral with the main flange (14) and carries the central hub (16).  10) Double flywheel according to claim 9 and 3, characterized in that the friction washer internally closes a cavity (15) in combination with said annular projecting nose (30).