WO2018020155A1

WO2018020155A1 - Vibration damping system for a motor vehicle driveline

Info

Publication number: WO2018020155A1
Application number: PCT/FR2017/052083
Authority: WO
Inventors: Christophe Dhalleine; Daniel Fenioux; Ivan Dutier; Antonin Cheron; Jérôme BOULET
Original assignee: Valeo Embrayages
Priority date: 2016-07-28
Filing date: 2017-07-26
Publication date: 2018-02-01
Also published as: FR3054632A1; FR3054632B1

Abstract

a vibration damping system for a motor vehicle driveline comprising: a first element (2) and a second element (3), rotatable relative to each other about a rotational axis X; a damping elastic device coupling the first and second elements and comprising: two raceways (15, 16) which are each linked to the first element (2); two raceways (13, 14) which are each linked by an elastic connection (17, 18) to the second element (3); a first and a second rolling body (11, 12) suitable for moving on said raceways during relative rotation between the first and second elements; and a phasing element (19, 20) arranged for maintaining a constant relative angular position between the first and second rolling bodies (11, 12); said first and second rolling bodies (11, 12) each being rotatably mounted on the phasing element via a pivot (22, 23).

Description

VIBRATION DAMPING SYSTEM FOR A MOTOR VEHICLE TRANSMISSION CHAIN

Technical area

The invention relates to the field of vibration damping systems for equipping motor vehicle transmissions.

Technological background

Motor vehicle transmissions are generally equipped with a damping system for filtering vibrations upstream of the gearbox so as to avoid particularly undesirable shocks, noises or noise. Such damping systems include damping dual flywheels (DVA) and / or clutch friction, in the case of a manual or robotic transmission, or locking clutches, also called "lock-up" clutches, equipping the hydraulic coupling devices, in the case of an automatic transmission.

The damping systems comprise resilient damping means rotatably coupling an input member and an output member so as to allow torque transmission and damping of rotational acyclisms.

The document FR3000155 discloses a damping system in which the elastic damping means are formed of two flexible blades. The two flexible blades are mounted on one of the input and output elements of the damping system and each cooperate with an associated roller rotatably mounted on the other of the input and output elements. The flexible blades and the rollers are arranged such that, for an angular displacement between the input element and the output element, on either side of a relative angular position of rest, the roller moves along a cam surface carried by the blade and, in doing so, exerts a bending force on the flexible blade. By reaction, the flexible blade exerts on the roller a return force which tends to bring the input and output elements to their angular position of rest. The flexion of the flexible blade thus makes it possible to damp the vibrations and irregularities of rotation between the input element and the output element while ensuring the transmission of the torque. The performance of such a vibration damping system depends on the angular stiffness of the flexible blades. Indeed, the lower the angular stiffness of the damping device and the better its performance is advantageous. However, the flexible blades must be sufficiently stiff to allow transmission of the maximum torque generated by the engine. Thus, in order to allow a reduction of the angular stiffness of a damping system while allowing the transmission of the maximum torque that can be delivered by the motor, the maximum relative angular displacement between the elements of the motor must be increased. entry and exit. However, given the constraints related to the size of the blades, the angular clearance of a damping system as described in document FR3000155 remains limited.

Moreover, the torque transmitted between the input element and the output element is taken up by the support axes of the rollers which are capable of deforming.

Finally, the characteristic curve representative of the torque transmitted as a function of the angular displacement rests solely on the profile of the cam surfaces carried by the flexible blades and along which the rollers roll. However, the shape of the flexible blades is subject to many other design constraints, such as the size and stiffness of each blade, so that certain curves can not be realized.

The filtration performance of a damping system as described in the aforementioned document FR3000155 are therefore not fully satisfactory.

summary

An idea underlying the invention is to provide a vibration damping system for effectively filtering vibrations.

According to one embodiment, the invention provides a vibration damping system for a motor vehicle transmission chain comprising:

a first element and a second element movable in rotation relative to each other about an axis of rotation X;

an elastic damping device coupling the first and the second elements so as to allow vibration damping torque transmission between the first element and the second element; said elastic damping device comprising:

a first and a second raceway which are each connected to the first element;

a third and a fourth raceway which are each connected by an elastic connection to the second element;

a first and a second rolling body; the first rolling body cooperating with the first and third raceways and being able to move on said first and third raceways during a relative rotation between the first and the second elements and the second rolling body cooperating with the second rolling body; and the fourth raceway and being adapted to move on said second and fourth raceways during relative rotation between the first and second members; said first, second, third and fourth raceways being arranged such that, for relative rotation between the first and second members from an angular rest position, the first and second rolling bodies moving on the rolling tracks respective ones exert a bending force on the elastic links and the elastic connections thus each produce a reaction force on one of the first and second rolling bodies; the reaction forces being able to return said first and second elements towards the angular position of rest; and - a phasing element, free in rotation with respect to the first element and the second element, connecting the first and the second rolling bodies so as to maintain a constant relative angular position between the first and the second rolling bodies; said first and second rolling bodies being each rotatably mounted on the phasing element via a pivot.

Thus, each rolling body is movable relative to the first and second elements, which makes it possible to increase the maximum angular displacement between the first element and the second element relative to a damping system according to the prior art, such as previously described. Such a damping device thus makes it possible, for a maximum torque to be transmitted determined, to reduce the angular stiffness which leads to a significant increase in filtration performance.

In addition, in such a damping system, the characteristic curve, that is to say the curve representing the torque transmitted as a function of the angular displacement, depends both on the geometry of the raceways connected by a elastic connection to the second element and rolling tracks connected to the first element while it depends only on the geometry of the cam carried by the blade in a blade damping system according to the prior art. Therefore, such an arrangement is likely to offer a wider variety of representative curves of the torque transmitted as a function of the travel.

In addition, the torque is transmitted between the first element and the second element through the rolling body without passing through a support pin may deform. Such an arrangement therefore makes it possible to provide a particularly robust vibration damping system.

Finally, thanks to said phasing element, a synchronization of the movements of the two rolling bodies on their respective raceways is ensured, which ensures proper operation of the damping system.

According to other advantageous embodiments, such a damping system may have one or more of the following characteristics.

According to one embodiment, the first and the second rolling track are arranged in such a way that the first and second rolling bodies move radially during a relative rotation between the first and the second elements.

According to one embodiment, the phasing element is arranged to allow a radial displacement of the rolling bodies with respect to the X axis.

According to one embodiment, the phasing assembly is centered and guided in rotation about the X axis on one of the first and second elements.

According to one embodiment, the damping system comprises a sliding bearing interposed between the phasing assembly and the element among the first and second elements on which the phasing assembly is centered and guided in rotation.

According to one embodiment, the phasing assembly comprises a cylindrical centering skirt and an axial abutment surface which are respectively supported on a cylindrical bearing surface and an axial bearing surface of the element among the first and second elements on which the phasing assembly is centered and guided in rotation. This ensures, on the one hand, a centering and guidance in rotation around the axis X of the phasing assembly and, secondly, contributes to ensuring accurate axial positioning of the phasing assembly and, therefore, rolling bodies.

According to one embodiment, the plain bearing comprises a first portion which is radially interposed between the cylindrical bearing surface and the cylindrical centering skirt and a second portion which is axially interposed between the axial bearing surface and the axial abutment surface. .

According to one embodiment, the phasing assembly comprises a phasing washer and a first and second clevis elements which are fixed to said phasing washer; each of the first and second rolling bodies being disposed axially between the phasing washer and one of the clevis members and comprising two pivot rods which are respectively housed in an orifice formed in the phasing washer and in an orifice formed in the screed element.

According to one embodiment, the rolling bodies are cylindrical rollers.

According to one embodiment, the rods protrude axially from one and the other of the two bases of the cylindrical rollers.

According to one embodiment, the orifices formed in the phasing washer and in the first and second clevis members are grooves developing in a radial direction.

According to one embodiment, the rods of the first and second rolling bodies are each housed in a guide bearing which is housed in one of the orifices formed in the phasing washer and in one of the clevis elements.

According to one embodiment, each guide bearing comprises a collar interposed axially between a base of the rolling body and the phasing washer or one of the clevis members and a guide body housed in one of the orifices.

According to one embodiment, the guide bearing is made of a material with a low coefficient of friction. According to one embodiment, the first element comprises an annular portion extending radially and a cylindrical skirt extending axially towards the second element from an outer periphery of the annular portion.

According to one embodiment, the first and second race tracks are formed on an inner surface of the cylindrical skirt.

According to one embodiment, the damping system further comprises at least one elastic holding member which is fixed against one end of the cylindrical skirt opposite the annular portion and which is arranged to exert on the assembly of phasing a force elastic adapted to maintain said phasing assembly against the annular portion of the first element.

According to one embodiment, the damping system comprises two elastic annular segments which are fixed against one end of the cylindrical skirt respectively along the first and second raceways and which are arranged to exert on the whole of phasage an elastic force adapted to maintain said phasing assembly against the annular portion of the first element.

According to one embodiment, the phasing assembly is able to deform elastically, in the radial direction, so as to allow radial movement of the rolling bodies with respect to the axis X.

According to one embodiment, the phasing assembly comprises two phasing washers which are connected to one another and arranged axially on the one side and on the rolling bodies.

According to one embodiment, the phasing washers are each able to deform elastically so as to allow radial movement of the rolling bodies with respect to the X axis.

According to one embodiment, the phasing washers are connected to one another by a first and a second rod respectively forming a pivot for one and the other of the first and second rolling bodies.

According to one embodiment, each rod has two ends which are respectively mounted tightly in an orifice of one and the other of the two phasing washers. According to one embodiment, the first and second rolling bodies are rollers and are respectively rotatably mounted on the first and second rods.

According to one embodiment, the rollers are rotatably mounted on the rods by means of rolling elements.

According to one embodiment, when the elastic damping device comprises only two rolling bodies, the phasing assembly provides a diametrically opposite positioning of the two rolling bodies.

According to one embodiment, the third and fourth raceways are each carried by a respective flexible blade attached to the second element.

According to one embodiment, the two phase washers are arranged axially on either side of the flexible blades, which ensures axial positioning of the phasing assembly relative to the flexible blades.

According to one embodiment, each flexible blade is arranged to deform in a plane perpendicular to the axis of rotation X.

According to one embodiment, each flexible blade has a free distal end and is arranged in such a way that the radial distance separating the axis of rotation X from said free distal end varies as a function of the angular displacement between the first element and the second element. .

According to one embodiment, the rolling bodies are arranged radially outside their respective flexible blade. Such an arrangement makes it possible to retain the flexible blade radially when it is subjected to centrifugal force.

According to one embodiment, the flexible blades are evenly distributed around the axis of rotation X.

According to one embodiment, the two flexible blades are symmetrical to each other with respect to the axis of rotation X.

According to one embodiment, each flexible blade has a portion bent around the axis of rotation X. According to one embodiment, the first and third raceways are arranged facing each other, on either side of the first rolling body, and the second and fourth raceways are arranged facing each other. , on both sides of the second rolling body.

According to one embodiment, the third and the fourth raceway are respectively located radially inside the first and second raceways.

According to one embodiment, the first, second, third and fourth raceways have profiles arranged such that, when a torque is transmitted between the first element and the second element, the rolling bodies each exert a bending force on one of the flexible blades causing a coming of a free distal end of the flexible blades towards the X axis and a relative rotation between the first and second elements such that the first and second element deviate from their relative position of rest .

According to one embodiment, the profiles of the rolling tracks are such that the rolling bodies exert on the associated flexible blade a bending force having a radial component and a circumferential component.

According to one embodiment, the rolling tracks are smooth.

According to another embodiment, each rolling member comprises a pinion equipped with a toothing which meshes with a toothing formed on one and / or the other of the two associated raceways.

According to one embodiment, each flexible blade has a fixing portion on the second element and an elastic portion having an inner strand, an outer strand and a bent portion connecting the inner strand and the outer strand.

According to one embodiment, the third and fourth raceways are each formed on a part which is attached to one of the flexible blades. In another embodiment, the third and fourth raceways are each formed in the mass of the respective flexible blade.

According to one embodiment, the damping system is a double damping flywheel comprising a primary flywheel and a secondary flywheel, the first element forming one of the primary and secondary flywheels and the second element forming the other.

According to one embodiment, the first and second raceways develop in a circular manner about the axis of rotation.

Thus, because of the circular path followed by the rolling bodies, it is not necessary to allow radial displacement of the rolling bodies. For example, the orifices in the phasing washer may be circular orifices fitted to the pivot and / or the phasing washers may be rigid.

According to one embodiment, the invention also provides a motor vehicle comprising such a damping system.

Brief description of the figures

The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly in the course of the following description of several particular embodiments of the invention, given solely for illustrative and non-limiting purposes. with reference to the accompanying drawings.

- Figure 1 is a half-sectional view along a radial plane of a double damping flywheel according to a first embodiment.

- Figure 2 is a half-sectional view along the plane ll-ll of the double damping flywheel of Figure 1.

- Figure 3 is a partial front view of the double damping flywheel of Figures 1 and 2 in which the secondary flywheel is not shown.

- Figure 4 is a partial perspective view of the double damping flywheel of Figures 1 to 3 in which the secondary flywheel is not shown.

- Figure 5 is a schematic sectional view along a radial plane of the double damping flywheel of Figures 1 to 4 illustrating in detail a rolling member and the phasing assembly.

- Figure 6 is a view similar to that of Figure 5 for a double damping flywheel according to a second embodiment.

- Figure 7 is a partial sectional view along a radial plane of a double damping flywheel according to a third embodiment. - Figure 8 is a partial front view of the double damping flywheel of Figure 7 in which the secondary flywheel is not shown.

- Figure 9 is a partial perspective view of the double damping flywheel of Figures 7 and 8 in which the secondary flywheel is not shown.

Detailed description of embodiments

In the description and the claims, the terms "external" and "internal" as well as the "axial" and "radial" orientations will be used to designate, according to the definitions given in the description, elements of the vibration damping system. . By convention, the "radial" orientation is directed orthogonal to the X axis of rotation of the damping system determining the "axial" orientation and, from the inside towards the outside away from said axis, the "circumferential" orientation is directed orthogonally to the axis of the damping system and orthogonal to the radial direction. The terms "external" and "internal" are used to define the relative position of one element relative to another, with reference to the X axis of rotation of the damping system, an element close to the axis is thus described as internal as opposed to an external element located radially periphery. Furthermore, the terms "rear" AR and "front" AV are used to define the relative position of one element relative to another in the axial direction, an element intended to be placed close to the engine being designated by the rear and an element intended to be placed close to the gearbox being designated by before.

The vibration damping system is intended to be arranged in the transmission chain of a motor vehicle, between the internal combustion engine and the gearbox. It can be incorporated in particular a double damping flywheel, a clutch mechanism, a coupling clutch of a hydraulic coupling device or a clutch disc.

In the figures and the description below, the vibration damping system is a double damping flywheel.

In relation with FIGS. 1 to 5, a double damping flywheel 1 is observed according to a first embodiment. The double damping flywheel 1 comprises a primary flywheel 2, intended to be fixed at the end of a crankshaft of an internal combustion engine, not shown, and a flywheel of inertia secondary 3, shown in Figure 1, which is centered and guided on the primary flywheel 2 by means of a bearing 4, such as a rolling bearing ball. The primary and secondary flywheels 3 are intended to be mounted movably about an axis of rotation X and are, moreover, rotatable relative to each other about said axis X.

The secondary flywheel 3 is intended to form the reaction plate of a clutch, not shown, connected to the input shaft of a gearbox. To do this, the secondary flywheel 3 has a friction surface 5, annular and flat, facing forward and intended to cooperate with the friction linings of a clutch plate, not shown, when the clutch device is in the engaged state. The clutch disc is integral in rotation with an input shaft of the gearbox. Thus, the torque is transmitted between the crankshaft of the engine and the input shaft of the gearbox when the clutch device is in the engaged state.

The primary flywheel 2 comprises an inner hub 6 supporting the bearing 4, an annular portion 7 extending radially outwardly from the inner hub 6 and a cylindrical skirt 8 extending axially forwards from the outer periphery of the the annular portion 7.

As shown in Figures 2 to 4, the primary flywheel 2 is provided with orifices 9 formed in its annular portion 7 and allowing the passage of fasteners, such as screws, not shown, for fixing the primary flywheel 2 on the crankshaft of the engine. The secondary flywheel 3 also has orifices, not shown, which are arranged vis-à-vis the orifices 9 of the primary flywheel 2 and which are intended for the passage of the fasteners, when mounting the double damping flywheel 1 on the crankshaft .

The primary flywheel 2 carries on its outer periphery, a drive ring 10, toothed, for driving in rotation of the primary flywheel 2, using a starter.

The double damping flywheel 1 also comprises an elastic damping device which couples the primary flywheel 2 and the secondary flywheel 3 so as to allow a torque transmission with vibration damping between the primary flywheel 2 and the secondary flywheel 3. The elastic damping device comprises two rolling bodies 1 1, 12 which are each interposed between, on the one hand, a rolling track 13, 14 which is connected to the secondary flywheel 3 by an elastic connection and, on the other hand, a running track 15, 16 which is connected to the primary flywheel 2. In the embodiment shown, the elastic links are formed by two flexible blades 17, 18 respectively carrying one and the other of the two raceways 13, 14, connected to the secondary flywheel 3. In other words, each of the two rolling bodies 1 1, 12 is interposed radially between a rolling track 13, 14 carried by one of the flexible blades 17, 18 and a running track 15. , 16 carried by the primary flywheel 2. In an alternative embodiment not shown, the structure is reversed and the flexible blades 17, 18 are fixed on the primary flywheel 2 while the rolling bodies 1 1, 12 are interposed radially between a track bearing carried by one of the flexible blades 17, 18 and a rolling track carried by the secondary flywheel 3.

When a torque is transmitted between the primary flywheel 2 and the secondary flywheel 3, each rolling body January 1, 12 rolls against one and the other of the two associated raceways 13, 15; 14, 16 and moves relative to the primary flywheel 2 and the secondary flywheel 3 in two opposite directions. The rolling bodies 1 1, 12 thus allow relative rotation between the primary flywheels 2 and secondary 3. Furthermore, the rolling tracks 13, 14, 15, 16 have profiles arranged so that, during such rotation relative between the primary flywheels 2 and secondary 3 from their relative position of rest, the rolling bodies January 1, 12 each exert a bending force on their respective flexible blade 17, 18 and thus cause a rapprochement of the free distal end of the blades The profiles of the rolling tracks 13, 14, 15, 16 are such that the rolling bodies exert on the flexible blades a bending force having a radial component and a circumferential component.

In response, the flexible blades exert on the rolling bodies 1 1, 12 a restoring force having a circumferential component which tends to rotate the rolling bodies 1 1, 12 in an opposite direction of rotation and to recall therefore the primary flywheels 2 and secondary 3 to their relative position of rest and a radial component directed outwards so as to keep the rolling bodies in contact with their respective raceways 13, 14, 15, 16. The circumferential forces thus make it possible to transmit the torque from one steering wheel to the other.

The profiles of the rolling tracks 13, 14, 15, 16 may be arranged in such a way that the characteristic curve representative of the torque transmitted as a function of the angular displacement is symmetrical or not with respect to the relative position of rest. According to an advantageous embodiment, the angular deflection may be greater in the forward direction than in the retro direction.

In the embodiment shown, the rolling bodies 11, 12 are cylindrical rollers. The cylindrical rollers may be solid or hollow. It is also possible to use rolling bodies 11, 12 having other shapes. The rolling bodies may in particular be made of rolling steel.

In addition, according to another embodiment not shown, the rolling bodies January 1, 12 are pinions or toothed wheels which mesh in teeth in the raceways 13, 14, 15, 16.

As represented in FIGS. 1 to 5, the rolling tracks 15, 16 carried by the primary flywheel 2 are formed in the inner surface of the cylindrical skirt 8 of the primary flywheel 2. These running tracks 15, 16 may be made by molding or machining in the mass of the primary flywheel 2 or be carried out on a part which is attached to the primary flywheel 2. The running tracks 15, 16 have, when they are observed along the axis of rotation X, an arcuate shape whose concavity is directed towards the axis of rotation X. Thus, for any point of the rolling tracks 15, 16, the radius of curvature is less than the distance between the point considered and the axis X. Thus, when the rolling bodies 1 1, 12 move away in one direction or the other, their relative position of rest, illustrated in Figures 2 to 4, the rolling bodies 1 1, 12 are close to the X axis.

The two flexible blades 17, 18 are regularly distributed around the X axis and are symmetrical with respect to the X axis so as to ensure the balance of the double damping flywheel 1. The flexible blades 17, 18 are for example made of a spring steel. It is further observed that each flexible blade 17, 18 is attached independently to the secondary flywheel 3. To this end, each elastic blade 15, 16 comprises a fixing portion fixed on the secondary flywheel 3 via a plurality of rivets, three in the embodiment represent. In addition, each flexible blade 17, 18 here comprises an inner strand, an outer strand and a bent portion connecting the inner strand and the outer strand. Such a flexible blade is described in detail in the document W01605061 1.

The rolling tracks 13, 14 are formed on the outer surface of the flexible blades 17, 18. The raceways can be formed directly in the mass of the flexible blades 17, 18 or be provided on separate parts which are attached to the blades. flexible 17, 18.

Furthermore, the elastic damping device comprises a phasing element which is free to rotate relative to the primary flywheel 2 and the secondary flywheel 3 and which is arranged to maintain a constant relative angular position between the two rolling bodies 1 1, 12 .

In the embodiment of FIGS. 1 to 5, the phasing element comprises a phasing washer 19 and two clevis elements 20, 21 which respectively make it possible to fix in rotation the one and the other of the two rolling bodies 1 1 , 12 on the phasing washer 19. To do this, each rolling body January 1, 12 is disposed axially between the phasing washer 19 and the clevis member 20, 21 and comprises two rods 22, 23 forming pivot respectively projections axially forward and backward.

As shown in detail in Figure 5, the two rods 22, 23 are respectively housed in a groove 24 formed in one of the clevis members 20, 21 and in a groove 25 formed in the phasing washer 19. The grooves 24, 25 develop in a radial direction. Thus, the rolling bodies 1 1, 12 are rotatably mounted on the phasing element while allowing a radial movement of the rolling body January 1, 12 relative to the axis X. Such a radial movement of the rolling bodies 1 1 , 12 relative to the axis X is indeed necessary to allow them to roll on the raceways 15, 16 formed in the inner surface of the cylindrical skirt 8, given their curved shape.

As shown in FIG. 4, each clevis element 20, 21 comprises a cheek 26 in which is formed one of the grooves 24 and extending in a plane orthogonal to the axis X, parallel to the phasing washer 19 and two fixing lugs 27, 28 which extend circumferentially from on both sides of the respective rolling body 1 1, 12. The fixing lugs 27, 28 are for example welded to the phasing washer 19.

The phasing element is centered and guided in rotation around the axis X on the primary flywheel 2. To do this, as shown in FIGS. 1 and 5, the phasing washer 19 has an internal portion which is folded towards the rearward, that is to say towards the primary flywheel 2, so as to provide, on the one hand, an axial abutment surface 29 and, on the other hand, a cylindrical centering skirt 30 of axial orientation. The annular portion 7 of the primary flywheel 2 comprises a cylindrical bearing surface 31 centered around the axis X and an axial bearing surface 32 which cooperate respectively with the cylindrical centering skirt 30 and with the axial abutment surface 29 of the phasing washer 19 with interposition of a sliding bearing 33. To this end, the sliding bearing 33 comprises a first cylindrical portion of axial orientation, which is radially interposed between the cylindrical bearing surface 31 of the primary flywheel 2 and the skirt cylindrical centering 30 of the phasing washer 19 and a second portion, radially oriented, which is axially interposed between the axial bearing surface 32 of the primary flywheel 2 and the axial abutment surface 29 of the phasing washer 19. The sliding bearing 33 is made of a material having a low coefficient of friction. By way of example, the plain bearing comprises a metal structure which is coated with PTFE (polytetrafluoroethylene).

Furthermore, as shown in FIGS. 3, 4 and 5, the double damping flywheel 1 comprises two elastic annular segments 34, 35 making it possible to hold the rolling bodies 11, 12 and the phasing element axially in the forward direction. . The annular elastic segments 34, 35 are for example formed in a spring steel sheet. The resilient annular segments 34, 35 are attached to the primary flywheel 2, against the forward end of the cylindrical skirt 8. Each of the resilient annular segments 34, 35 extends along one of the raceways 15, 16 Also, each of the resilient annular segments 34, 35 exerts an axial force on the cheek 26 of one of the clevis members 21 and thus makes it possible to press the phasing element against the annular portion 7 of the primary flywheel 1, and more particularly to press the axial abutment surface 29 of the phasing washer 19 against the annular portion 7 of the primary flywheel 1. Such an arrangement makes it possible to guarantee precise axial positioning of the rolling bodies 1 1, 12. According to another alternative embodiment, not illustrated, the double damping flywheel may comprise a single elastic ring which is fixed on the primary flywheel 2, against the front end of the cylindrical skirt 8 and which cooperates with the two clevis elements 20 , 21 so as to maintain axially in the forward direction the rolling bodies 1 1, 12 and the phasing element.

Figure 6 illustrates in detail the phasing element and the rolling bodies 11, 12 according to another embodiment. This embodiment differs from the embodiment described above in relation to FIGS. 1 to 5 only in that the two rods 22, 23 of the rolling bodies 1 1, 12 are each housed in a guide bearing 36. Each bearing guide 36 comprises a flange 37 of radial orientation and a guide body 38 of axial orientation. Each collar 37 is interposed axially between one of the bases of the rolling body 1 1, 12 and the phasing washer 19 or the clevis member 20. Furthermore, the guide body 38 is housed in an oblong hole of the washer 19 or of the clevis member 20 and has a groove 39, 40 in which is housed one of the rods 22, 23 of a rolling body January 1, 12. As in the previous embodiment, the groove 39, 40 develops in a radial direction so as to allow radial movement of the rolling bodies January 1, 12. The guide bearings 36 are made of materials having a low coefficient of friction. By way of example, the guide bearings are formed in a metal structure which is coated with PTFE. Such guiding bearings 36 are particularly advantageous in that they make it possible to reduce the friction and wear between the rolling bodies 11, 12, on the one hand, and the phasing element.

Figures 7 to 9 illustrate a double damping flywheel according to a second embodiment.

In this embodiment, the two flexible blades 17, 18 are connected to an annular central body 41 which forms a common fixing portion to the two flexible strips 17, 18.

Furthermore, the phasing member comprises two phasing washers 42, 43 which are connected to one another. As shown in FIG. 7, the two phasing washers 42, 43 are fixed to each other by means of a rod 44. The rod 44 has two ends 45, 46 which are each mounted tightly. in an orifice 47, 48 of one of the phasing washers 42, 43. The rods 44 thus form spacers connecting the two phasing washers 42, 43.

The rods 44 also each form a pivot about which a rolling member 1 1, 12 rotates. The rolling bodies 1 1, 12 are here rollers which are each mounted in rotation on one of the rods 44 via rolling elements 47, such as balls, rolls or needles. The rolling elements 47 are arranged in a running space which is formed radially between an outer race 48 which is formed on the inner periphery of the roller and an inner race 49 which is formed on the outer periphery of the rod 44. The rolling elements 47 are held axially inside the running space by means, on the one hand, of a collar 50 carried by the rod 44 and, on the one hand, a retaining ring 51 mounted on the rod 44.

The running space is advantageously filled with a lubricant, such as grease and gaskets to ensure the tightness of the rolling space.

Moreover, as represented in FIGS. 8 and 9, the two phasing washers 42, 43 are arranged axially on either side of the flexible blades 17, 18, which makes it possible to guarantee the relative axial positioning of the rolling members 1 1, 12 with respect to the flexible blades 17, 18.

Furthermore, the phasing washers 42, 43 are able to deform elastically so as to allow a radial movement of the rolling bodies 1 1, 12 with respect to the axis X. To do this, the phasing washers 42, 43 are dimensioned and formed in a material, such as a spring steel, for giving the phasing washers 42, 43 the required elasticity.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is not limited thereto and that it comprises all the technical equivalents of the means described and their combinations if they are within the scope of the invention.

In particular, although the invention is described above in connection with an elastic damping device comprising two sliding bodies each cooperating with two raceways, the invention is not limited to such an embodiment and the elastically damping device is also susceptible to include a greater number of rolling bodies, each of the rolling bodies being rotatably mounted on the phasing element.

The use of the verb "to include", "to understand" or "to include" and its conjugated forms does not exclude the presence of other elements or steps other than those set out in a claim. The use of the indefinite article "a" or "an" for an element or a step does not exclude, unless otherwise stated, the presence of a plurality of such elements or steps.

In the claims, any reference sign in parentheses can not be interpreted as a limitation of the claim.

Claims

1. Vibration damping system for a motor vehicle transmission chain comprising:

a first element (2) and a second element (3) rotatable relative to one another about an axis of rotation X;

an elastic damping device coupling the first and the second elements so as to allow vibration damping torque transmission between the first element (2) and the second element (3);

said elastic damping device comprising:

a first and a second raceway (15, 16) which are each connected to the first element (2);

- a third and a fourth raceway (13, 14) which are each connected by an elastic connection (17, 18) to the second element (3);

a first and a second rolling body (1 1, 12); the first rolling body (1 1) cooperating with the first and third raceways (15, 13) and being able to move on said first and third raceways during a relative rotation between the first and the second elements and the second rolling body (12) cooperating with the second and fourth raceways (16, 14) and being able to move on said second and fourth raceways during a relative rotation between the first and second elements ; said first, second, third and fourth raceways (13, 14, 15, 16) being arranged such that for relative rotation between the first and second members (2, 3) from an angular position of rest, the first and second rolling bodies moving on the respective rolling tracks (13, 14, 15, 16) exert a bending force on the elastic links (17, 18) and the elastic links (17, 18) thus produce each a reaction force on one of the first and second rolling bodies (1 1, 12); the reaction forces being able to return said first and second elements (2, 3) towards the angular position of rest; and

- a phasing element (19, 20, 21, 42, 43), free in rotation with respect to the first element (2) and the second element (3), connecting the first and second rolling bodies (1 1, 12) so as to maintain a constant relative angular position between the first and second rolling bodies (1 1, 12); said first and second rolling bodies (1 1, 12) being each rotatably mounted on the phasing element via a pivot (22, 23, 44).

A vibration damping system according to claim 1, wherein the first and second race tracks (15, 16) are arranged such that the first and second rolling bodies (1 1, 12) move radially. during a relative rotation between the first and the second elements (2, 3) and in which the phasing element (19, 20, 21, 42, 43) is arranged to allow a radial displacement of the rolling elements (1 1 , 12) with respect to the X axis.

3. A damping system according to claim 1 or 2, wherein the phasing assembly (19, 20, 21) is centered and guided in rotation about the X axis on one of the first and second elements (2). , 3).

4. damping system according to claim 3, further comprising a sliding bearing (33) interposed between the phasing assembly (19, 20, 21) and the element among the first and second elements (2, 3) on which the phasing assembly (19, 20) is centered and guided in rotation.

5. damping system according to claim 3 or 4, wherein the phasing assembly (19, 20, 21) comprises a cylindrical centering skirt (30) and an axial abutment surface (29) which are respectively in abutment. on a cylindrical bearing surface (31) and an axial bearing surface (32) of the first and second element (2, 3) on which the phasing assembly (19, 20) is centered and guided in rotation.

The damping system according to claim 5 taken in combination with claim 4, wherein the sliding bearing (33) has a first portion which is radially interposed between the cylindrical bearing surface (31) and the cylindrical centering skirt ( 30) and a second portion which is axially interposed between the axial bearing surface (32) and the axial abutment surface (29).

The damping system according to any one of claims 1 to 6, wherein the phasing assembly comprises a phasing washer (19) and first and second clevis members (20, 21) which are attached to said phasing washer (19); each of the first and second rolling bodies (1 1, 12) being disposed axially between the phasing washer (19) and one of the clevis members (20, 21) and having two pivot rods (22, 23) which are respectively housed in an orifice (25) formed in the phasing washer (19) and in an orifice (24) formed in the respective clevis element (20, 21).

8. A damping system according to any one of claims 7, wherein the orifices in the phasing washer (19) and in the first and second clevis elements (20, 21) are grooves developing in one direction. radial.

9. damping system according to claim 7 or 8, wherein the rods (22, 23) of the first and second rolling bodies (1 1, 12) are each housed in a guide bearing (36) housed in one orifices (24, 25) formed in the phasing washer (19) and formed in one of the clevis elements (20, 21).

10. A damping system according to any one of claims 1 to 9, wherein the first element (2) comprises an annular portion (7) extending radially and a cylindrical skirt (8) extending axially towards the second element (3) from an outer periphery of the annular portion and wherein the first and second raceways (15, 16) are provided on an inner surface of the cylindrical skirt (8).

1 1. A damping system according to claim 10, further comprising at least one resilient retaining member (34,35) which is secured against one end of the cylindrical skirt (8) which is opposed to the annular portion (7) and which is arranged to exert on the phasing assembly (19, 20, 21) an elastic force able to maintain said phasing assembly against the annular portion (7) of the first element (2).

12. damping system according to claim 1 or 2, wherein the phasing assembly (42, 43) is able to deform elastically so as to allow radial movement of the rolling bodies (1 1, 12) relative to the X axis.

13. damping system according to any one of claims 1, 2 and 12, wherein the phasing assembly comprises two phasing rings (42, 43) which are connected to one another and arranged axially of parts and rolling bodies (1 1, 12).

14. A damping system according to claim 13, wherein the phasing washers (42, 43) are connected to each other by a first and a second rods (44) respectively pivoting for one and the other. other first and second rolling bodies (1 1, 12).

15. damping system according to claim 14, wherein the first and second rolling bodies (1 1, 12) are rollers and are respectively rotatably mounted on the first and second rods (44).