FR3053750A1 - DOUBLE FLYWHEEL DAMPER WITH FLEXIBLE BLADE FIXED ON THE PRIMARY ELEMENT - Google Patents

Abstract

The invention relates to a double damping flywheel for a motor vehicle transmission chain comprising: - a primary flywheel (2) intended to be fixed to a drive shaft of the transmission chain; - a secondary flywheel (3) for forming a reaction plate for a clutch device; - A resilient damping member (22) for transmitting torque and damping rotational acyclisms between the primary flywheel (2) and the secondary flywheel (3); the elastic damping member (22) being rotationally integral with the primary flywheel (2) and having a cam (27) connected to the primary flywheel by an elastic connection, the cam cooperating with a cam follower (28); the cam follower (28) being supported by a support member (29) which is attached to the secondary flywheel (3); the support member (29) having a support portion (67) which is axially spaced from the outer portion (5) of the secondary flywheel (3) and the cam follower (28) being carried by the support portion so as to thermally isolating it from the annular friction surface (6) of the secondary flywheel (3).

Description

Technical area

The invention relates to the field of transmissions for a motor vehicle and more particularly relates to a double damping flywheel capable of filtering acyclisms of the engine.

Technological background

An internal combustion engine has, due to successive explosions in the engine cylinders, acyclisms whose frequency varies in particular depending on the number of cylinders and the engine rotation speed.

In order to filter the vibrations generated by acyclisms upstream of the gearbox, it is known to equip the vehicle transmissions with a double damping flywheel (DVA) making it possible to dampen the vibrations. Otherwise, vibrations entering the gearbox would cause particularly undesirable shocks, noises or noise pollution during operation.

The dual shock-absorbing flywheels include a primary flywheel and a secondary coaxial flywheel, which rotate with respect to each other. The primary flywheel is intended to be fixed to the crankshaft of the combustion engine. The secondary flywheel forms a reaction plate intended to cooperate with a clutch disc integral in rotation with the input shaft of the gearbox. The primary and secondary flywheels are coupled in rotation by an elastic damping member allowing to transmit a torque and to dampen the acyclisms of rotation between the primary flywheel and the secondary flywheel.

In document FR3008152, the elastic damping member which couples in rotation the primary and secondary flywheel comprises flexible blades mounted on one of the primary and secondary flywheels and each having a cam surface cooperating with an associated cam follower mounted mobile in rotation on the other flywheel. The flexing of the flexible blades makes it possible to dampen the vibrations and irregularities in rotation between the primary and secondary flywheels while ensuring the transmission of the torque.

According to an embodiment disclosed in the aforementioned document, the cam followers are carried by cylindrical rods fixed to the secondary flywheel while the flexible blades are fixed to the primary flywheel. Such an embodiment is not satisfactory because the cylindrical rods for fixing the cam followers are fixed to the secondary flywheel in or near the friction surface of the secondary flywheel intended to cooperate with a clutch disc. Consequently, the cam followers are, in use, subjected to high temperatures, which is liable to degrade them, in particular if they are cam followers with bearings or plain bearings which are particularly sensitive to elevations of temperatures.

According to another embodiment disclosed in the aforementioned document, the cam followers are fixed on the primary flywheel while the flexible blades are fixed on the secondary flywheel. If this embodiment makes it possible to overcome the difficulties linked to the temperature sensitivity of the cam followers, it has other drawbacks. In fact, in this case, the flexible blades are fixed to the secondary flywheel in an area located radially outside the fixing screws of the primary flywheel on the engine crankshaft, which limits their length and consequently restricts the performance of filtration of vibrations from the double damping flywheel. In addition, the flexible blades being fixed to the secondary flywheel, the inertia of the secondary flywheel is increased to the detriment of that of the primary flywheel, which has the undesirable effect of degrading the behavior of the double damped flywheel at startup. Finally, depending on the axial location on the primary flywheel of the drive ring intended to cooperate with the starter, said drive ring is capable of being located radially outside the cam followers, which limits the radius d implantation of the cam followers and consequently limits the maximum torque likely to be transmitted by the double damping flywheel.

summary

The invention aims to remedy these problems by proposing a reliable and efficient double damping flywheel.

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

- a primary flywheel intended to be fixed to a shaft leading from the transmission chain;

- a secondary flywheel intended to form a reaction plate for a clutch device; the primary flywheel and the secondary flywheel being movable in rotation relative to each other about an X axis; the secondary flywheel comprising an internal portion and an external portion radially outside the internal portion, the external portion having an annular friction surface intended to cooperate with the clutch device;

- an elastic damping member for transmitting a torque and damping the rotation acyclisms between the primary flywheel and the secondary flywheel; the elastic damping member being integral in rotation with the primary flywheel and comprising a cam connected to the primary flywheel by an elastic connection, the cam cooperating with a cam follower;

- the cam follower being supported by a support element which is fixed to the secondary flywheel; the support element comprising a support portion which is axially spaced from the external portion of the secondary flywheel, and the cam follower being carried by the support portion so as to thermally isolate it from the annular friction surface of the secondary flywheel .

Such an arrangement is particularly advantageous in that it makes it possible to free oneself from the difficulties linked to the temperature sensitivity of the cam follower while also overcoming the disadvantages linked to the fixing of the elastic damping member on the secondary flywheel. In particular, the inertia of the secondary flywheel is not increased by the fixing of the elastic damping member thereon, which makes it possible to avoid undesirable behaviors of the double damped flywheel during starting.

According to other advantageous embodiments, such a double damping flywheel may have one or more of the following characteristics:

According to one embodiment, the elastic damping member, the cam follower and the support element are housed in an intermediate space formed axially between the primary flywheel and the secondary flywheel.

According to one embodiment, the support element is fixed to the internal portion of the secondary flywheel.

According to one embodiment, the external portion of the secondary flywheel is offset axially from the internal portion of the secondary flywheel in a direction opposite to the support element so as to provide at least part of a space axially separating the external portion of the secondary flywheel of the support portion.

According to one embodiment, the support element comprises a central opening having an annular border and the internal portion of the secondary flywheel comprises a shoulder providing a surface of cylindrical bearing cooperating with the annular border of the central opening and a surface of axial support bearing against the support element. This guarantees precise and simple positioning of the support element and the cam followers relative to the secondary flywheel.

According to one embodiment, the support element is fixed to the secondary flywheel by a plurality of fixing members, such as rivets for example, each passing through an orifice formed in the support element and d 'An orifice formed in the internal portion of the secondary flywheel. According to one embodiment, the fixing members are regularly distributed around the axis X.

According to one embodiment, the elastic damping member comprises a plurality of cams which are each connected to the primary flywheel by an elastic link and each cooperate with a respective cam follower; each of the cam followers being carried by the support portion.

According to one embodiment, the cams are circumferentially distributed around the axis X. Similarly, according to one embodiment, the cam followers are circumferentially distributed around the axis X.

When the double damper flywheel has an even number of cams, two for example, the cams are symmetrical to each other with respect to the axis of rotation X, which contributes to the balance of the double damper flywheel.

According to one embodiment, each of the cam followers is fixed on a respective tab of the support element which extends radially outwards. According to an advantageous embodiment, each of the cam followers is fixed on a respective tab of the support portion which extends radially outwards. This limits the inertia of the support element.

According to one embodiment, the double damping flywheel comprises at least one member for fixing the primary flywheel to the driving shaft and the elastic transmission member comprises a fixing portion which is connected to the cam by the elastic connection and which is attached to the primary steering wheel; said fixing portion being provided with a passage opening for said member for fixing the primary flywheel to the driving shaft. According to one embodiment, the double damping flywheel comprises several members for fixing the primary flywheel to the driving shaft, each of the fixing members passing through a respective orifice formed in the fixing portion.

According to one embodiment, the primary flywheel has a plurality of holes facing each of the fixing members of the support element on the secondary flywheel.

According to one embodiment, the fixing portion is an annular central body.

According to one embodiment, the internal portion of the secondary flywheel comprises a hub supporting a bearing; said bearing supporting the annular central body of the elastic damping member so as to guide the primary flywheel in rotation relative to the secondary flywheel.

According to an embodiment in which the double damping flywheel comprises a plurality of cams, the cams are fixed to the first element by a common fixing portion. Such a common fixing portion can in particular be formed by an annular central body.

In addition, in such a case, the cams are advantageously carried by flexible blades which are formed integrally with the fixing portion.

According to other embodiments not shown, the elastic transmission members are each formed of a separate element and are thus each fixed to the primary flywheel by an independent fixing portion.

According to one embodiment, the cam follower is a roller mounted to move in rotation on the support element by means of a bearing. The bearing is for example a lubricated rolling bearing.

According to one embodiment, the primary flywheel comprises an annular portion of radial orientation provided with an external periphery and a cylindrical skirt which is arranged radially outside the elastic damping member and the cam follower and s 'extends axially towards the secondary flywheel from the external periphery of the annular portion to a free edge of said cylindrical skirt which extends axially beyond the cam follower; the free edge of the cylindrical skirt supporting a drive ring and being offset radially inwards beyond the outermost point of the cam follower.

According to one embodiment, the annular portion of the primary flywheel has an opening which has a diameter greater than that of the cam follower and which is arranged to allow the mounting of the cam follower on the support element through the primary flywheel.

According to one embodiment, the drive ring is fixed to the support element.

According to one embodiment, the primary flywheel comprises an annular portion of radial orientation which comprises an internal part and an external part; said external part being offset axially with respect to the internal part in a direction opposite to the secondary flywheel; a part of the cam follower being arranged radially outside the internal part of the annular portion of the primary flywheel.

According to one embodiment, the primary flywheel further comprises a cylindrical skirt which is arranged radially outside the elastic damping member and of the cam follower and extends axially in the direction of the secondary flywheel from the external periphery the annular portion; the cylindrical skirt defining with the external part a cavity in which is partially housed the cam follower.

According to one embodiment, the double damping flywheel comprises a friction assembly arranged to exert a resistant friction torque during a relative rotation between the primary and secondary flywheels, the friction assembly comprising a friction washer pressed against the support element.

According to a first alternative embodiment, the friction assembly further comprises an elastic washer integral in rotation with the primary flywheel and exerting an axial force on the friction washer so as to press it against the support element.

According to a first alternative embodiment, the friction assembly further comprises:

- a cover which is mounted on the support element,

- An elastic washer which is supported on the cover and exerts an axial force on the friction washer so as to press it against the support element; and

- a drive member integral in rotation with the primary flywheel and capable of driving the friction washer in rotation relative to the support element during a relative rotation between the primary flywheel and the secondary flywheel.

According to one embodiment, the drive member cooperates with the friction washer with a determined circumferential clearance so that the friction washer is not driven in rotation relative to the support element so as to exert a torque friction resistant only when the circumferential play has been taken up.

According to one embodiment, the support element is formed in a metal sheet.

According to one embodiment, the metal sheet is heat treated. Such a metal sheet is a steel and preferably in a steel having a carbon content greater than 0.2% in order to make it suitable for undergoing heat treatments. Such a metal sheet is quenched and returned so as to give the support element the desired mechanical characteristics.

In one embodiment, the support member does not support a torsional damper with an oscillating mass of inertia.

In another embodiment, the double damping flywheel further comprises a torsional damper with oscillating mass of inertia supported by the support element.

According to one embodiment, the torsion damper with oscillating mass of inertia is a pendulum damper comprising a plurality of masses of inertia regularly distributed on the support element.

According to one embodiment, the pendulum damper comprises means for guiding the inertia masses which comprise, for each inertia mass, two rolling members which each cooperate with a first raceway carried by said inertia mass and with a second raceway carried by the support element.

According to an advantageous embodiment, each inertia mass comprises two sides extending axially on either side of the support element, the two sides being connected to one another by means of spacers of link which each pass through an associated opening formed in the support element.

According to one embodiment, each first raceway is formed on one of the connection spacers and each second raceway is formed by an outer edge of one of the openings for passage of a connection spacer made in the support element.

According to another embodiment not shown, the torsional damper with oscillating mass of inertia is an inertial beater comprising a mass of inertia which is coupled in rotation to the support element by means of a plurality of elastic return members capable of generating a force to return the mass of inertia relative to the support element in a relative position of equilibrium.

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

According to one embodiment, the cam follower is arranged radially outside the flexible blade. Such an arrangement allows the flexible blade to be retained radially when it is subjected to centrifugal force.

According to one embodiment, the flexible blade has a free distal end and is arranged so that the radial distance separating the axis of rotation X from said free distal end varies according to the angular clearance between the primary flywheel and the secondary flywheel .

According to one embodiment, the cam is arranged so that for a relative rotation between the primary flywheel and the secondary flywheel from a relative rest position, the cam follower exerts a bending force on the flexible blade which produces a force reaction of the flexible blade on the cam follower, this reaction force being able to return the primary and secondary flywheels to their relative rest position

According to one embodiment, the flexible blade has a portion curved around the axis of rotation X.

According to one embodiment, the secondary flywheel is centered and guided in rotation on the primary flywheel by means of a bearing, such as a rolling bearing.

According to one embodiment, the primary flywheel comprises an internal hub supporting a bearing which guides the secondary flywheel on the primary flywheel.

According to one embodiment, the primary flywheel comprises an annular portion having orifices for passage of the members for fixing the primary flywheel to the driving shaft.

According to one embodiment, the invention also provides a double damping flywheel for a motor vehicle transmission chain comprising:

- a primary flywheel intended to be fixed to a shaft leading from the transmission chain;

- a secondary flywheel intended to form a reaction plate for a clutch device; the primary flywheel and the secondary flywheel being movable in rotation relative to each other about an X axis;

- an elastic damping member for transmitting a torque and damping the rotation acyclisms between the primary flywheel and the secondary flywheel; the elastic damping member comprising a cam cooperating with a cam follower; the cam being connected by an elastic link to one of the primary flywheel and the secondary flywheel and the cam follower being integral in rotation with the other; the primary flywheel comprising an annular portion of radial orientation provided with an external periphery and a cylindrical skirt which is arranged radially outside the elastic damping member and the cam follower and extends axially in the direction of the secondary flywheel from the outer periphery of the annular portion to a free edge of said cylindrical skirt which extends axially beyond the cam follower; the free edge of the cylindrical skirt supporting a drive ring and being offset radially inwards beyond the radius of the outermost point of the cam follower.

Such a double damping flywheel having such an arrangement is particularly advantageous in that, for a set-up diameter of the drive crown, the set-up diameter of the cam follower can be increased as well as the torque transmissible by the double damping flywheel.

Such a double shock-absorbing flywheel can also have any of the additional characteristics mentioned above.

According to one embodiment, the invention also provides a motor vehicle comprising a double damping flywheel mentioned above.

Brief description of the figures

The invention will be better understood, and other objects, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely by way of illustration and without limitation. , with reference to the accompanying drawings.

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

- Figure 2 is a front perspective view of the secondary flywheel and the support element of the cam followers of the double damping flywheel of Figure 1.

- Figure 3 illustrates the elastic damping members and the cam followers of the double damping flywheel of Figure 1.

- Figure 4 is a rear perspective view of the secondary flywheel and of the support element for the cam followers of the double damped flywheel of Figure 1.

- Figure 5 is a perspective front view of the double damping flywheel of Figure 1.

- Figure 6 is a rear perspective view of the double damping flywheel of Figure 1.

- Figure 7 is a sectional view of a double damping flywheel according to a second embodiment.

- Figure 8 is a detailed view of zone VIII of Figure 7.

- Figure 9 is a sectional view along the axis IX-IX of the double damping flywheel of Figure 7.

- Figure 10 is a sectional view of a double damping flywheel according to a third embodiment.

- Figure 11 is a partial view of a double damping flywheel according to a fourth embodiment in which the secondary flywheel and the support element are not shown.

- Figure 12 is a sectional view along the axis XII-XII of the double damping flywheel of Figure 11.

FIG. 13 is a cutaway perspective view of the double damping flywheel in FIGS. 11 and 12.

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 double damping flywheel. By convention, the radial orientation is directed orthogonally to the axis X of rotation of the double damping flywheel determining the axial orientation and, from the inside towards the outside while moving away from said axis, the circumferential orientation is directed orthogonally to the axis of the double damping flywheel and orthogonally to the radial direction. The terms external and internal are used to define the relative position of an element with respect to another, with reference to the axis X of rotation of the double damping flywheel, an element close to the axis is thus qualified as internal by opposition to an external element located radially on the periphery. Furthermore, the terms rear AR and front AV are used to define the relative position of one element with respect to another in the axial direction, an element intended to be placed close to the heat engine being designated by rear and an element intended to be placed close to the gearbox being designated by front.

In connection with FIGS. 1 to 6, a double damping flywheel 1 is described according to a first embodiment.

The double damping flywheel 1 comprises a primary flywheel 2, intended to be fixed to the end of a shaft driving the transmission chain, such as the crankshaft of an internal combustion engine, not shown, and a flywheel d 'secondary inertia 3 which is centered and guided on the primary flywheel 2 by means of a bearing 4, such as a ball bearing. The primary 2 and secondary 3 flywheels are intended to be mounted mobile around an axis of rotation X and are, moreover, mobile in rotation relative to each other around said axis X.

The secondary flywheel 3 is intended to form the reaction plate of a clutch device, not shown. To do this, the secondary flywheel 3 comprises, on an external portion 5, a friction surface 6, annular and flat, facing forward and intended to cooperate with the friction linings of a clutch disc, not shown. , when the clutch device is in the engaged state. The clutch disc rotates with a gearbox input shaft. Thus, the torque is transmitted between the engine crankshaft and the gearbox input shaft when the clutch device is in the engaged state.

Furthermore, as shown in particular in Figure 2, the secondary flywheel 3 comprises, near its outer edge, studs 7 and orifices 8 used for mounting a cover of the clutch device.

The primary flywheel 2 comprises an internal hub 9 supporting the bearing 4, an annular portion 10 extending radially outward from the internal hub 9 and a cylindrical skirt 11 extending axially, forwardly, from the external periphery of the annular portion 10.

In the embodiment shown, the bearing 4 is a rolling bearing. The internal hub 9 of the primary flywheel 2 has a shoulder 12, serving to support the internal ring of the bearing 4 and retaining said internal ring towards the rear in the direction of the engine. In addition, the internal ring is retained forwards by means of an annular elastic ring 13 or circlip mounted in a groove formed in the internal hub 9. Similarly, the secondary flywheel 3 has on its internal periphery a shoulder 14 serving in support of the outer ring of the bearing 4 and retaining said outer ring forward. In addition, the outer ring is retained rearward by means of an annular elastic ring 15 or circlip mounted in a groove formed in the inner periphery of the secondary flywheel 3. As a variant, the rolling bearing can be replaced by a bearing smooth.

The primary flywheel 2 is provided with orifices 16 formed in an internal part 17 of its annular portion 10 and allowing the passage of fastening members 18, such as screws, intended for fixing the primary flywheel 2 on the engine crankshaft . The secondary flywheel 3 also comprises orifices 19 which are formed in an internal portion 20 of the secondary flywheel 3 and, arranged opposite the orifices 16 of the primary flywheel 2. The orifices 19 are intended for the passage of the fastening members 18, during mounting the double damping flywheel 1 on the drive shaft.

The primary flywheel 2 carries, on its outer periphery, a toothed drive ring 21, for the rotary drive of the primary flywheel 2, using a starter.

In FIGS. 1 and 3, the structure of the elastic damping member 22 is observed coupling the primary flywheel 2 and the secondary flywheel 3 and making it possible to dampen the vibrations between the primary flywheel 2 and the secondary flywheel 3.

The elastic damping member 22 comprises flexible blades 23 and is secured in rotation to the primary flywheel 2. In the embodiment shown, the elastic damping member 22 is formed in a single piece which is fixed to the flywheel primary 2 by a common fixing portion ensuring the fixing of all the flexible blades 23. The common fixing portion here comprises an annular central body 24.

As shown in Figure 1, the annular central body 24 is centered on a rear portion of the inner hub 9 of the primary flywheel 2. Furthermore, the annular central body 24 has a plurality of orifices 25 which are circumferentially distributed around the axis X and which each come opposite one of the orifices 16 of the primary flywheel 2. The orifices 25 allow the passage of the fastening members 18. As shown in FIG. 1, each of the orifices 16 has a countersink 26 making it possible to accommodate at least partially the head of the fixing members 18. Thus, in the embodiment shown, it is the same fixing members 18 which ensure the fixing of the elastic damping member 22 to the primary flywheel 2 and the fixing of the flywheel primary 2 to the leading tree.

In another embodiment not shown, the elastic damping member 22 is also fixed to the primary flywheel 2 via additional fixing members, such as rivets. Such additional fasteners make it possible to ensure precise relative positioning of the elastic damping member 22 relative to the primary flywheel 2 even when the fasteners for the primary flywheel 2 on the driving shaft are absent.

For the two aforementioned embodiments, the fixing portion of the elastic damping member 22 is located in the area of passage of the fixing members of the primary flywheel 2 to the driving shaft, which allows, compared to the arrangement of the fixing portion radially outside the passage area of the fixing members of the primary flywheel 2 to the driving shaft, to have more space for the flexible blades 23. Consequently, the length of the flexible blades 23 can be increased, which consequently increases the vibration filtration performance of the double damping flywheel 1 for the same radial size.

In other embodiments not shown, the flexible blades 23 of the elastic damping member 22 are fixed independently to the primary flywheel 2 and each has a separate fixing portion.

Returning to FIG. 3, it can be seen that each flexible blade 23 has a cam or cam surface 27 which is arranged to cooperate with a respective cam follower 28 which is linked to the secondary flywheel 3. The cam followers 28 are held in abutment against their respective cam surface 27 and are arranged to roll against said cam surface 27 during a relative movement between the primary 2 and secondary 3 flywheels. Furthermore, the cam followers 28 are arranged radially to the outside their respective cam surface 27 so as to radially maintain the flexible blades 23 when they are subjected to centrifugal force.

Each cam surface 27 is arranged such that, for a relative rotation between the primary flywheel 2 and the secondary flywheel 3 in one direction or the other, from a relative angular position of rest, the cam follower 28 moves on the cam surface 27 and, in so doing, exerts a bending force on the flexible blade 23. By reaction, the flexible blade 23 exerts on the cam follower 28 a restoring force having a circumferential component which tends to bring back the flywheels primary 2 and secondary 3 towards their relative angular position of rest. Thus, the flexible blades 23 are capable of transmitting a driving torque from the primary flywheel 2 to the secondary flywheel 3 (direct direction) and a resistant torque from the secondary flywheel 3 to the primary flywheel 2 (retro direction). Furthermore, the torsional vibrations and the torque irregularities which are produced by the engine and transmitted by the crankshaft to the primary flywheel 2 are damped by the bending of the flexible blades 23.

If in the embodiment shown in FIG. 3, each flexible blade 23 is formed from a flexible monobloc piece, in another embodiment, the flexible blades can each comprise a rigid portion carrying the cam surface and an elastic connection , for example rubber, connecting the rigid portion to the fixing portion of the elastic damping member.

In FIGS. 1, 2 and 4, it can be seen that the elastic damping members 22 and the cam followers 28 are arranged in an intermediate space formed axially between the primary flywheel 2 and the secondary flywheel 3. The cam followers 28 are fixed on a support element 29 separate from the secondary flywheel 3. The cam followers 28 are more particularly fixed on a support portion 67 which is formed near the radially external periphery of the support element 29. The support element 29 is fixed to the secondary flywheel 3 in the internal portion 20 thereof. The rear face of the external portion 5 of the secondary flywheel 3 is offset radially forward with respect to the internal portion of the secondary flywheel 3 so as to provide a space 31 axially separating the external portion 5 of the secondary flywheel 3 from the portion of support 67. Such a space 31 makes it possible to thermally isolate the cam followers 28 from the friction surface 6 of the secondary flywheel 3.

The support element 29 has a central opening and is centered on the internal portion 20 of the secondary flywheel 3. To do this, the internal portion 20 of the secondary flywheel 3 has a shoulder which provides, on the one hand, a bearing surface cylindrical 30 centered around the axis X and an axial bearing surface 32. The cylindrical bearing surface 30 cooperates with the annular edge of the central opening so as to center the support element 29 on the secondary flywheel 3. The support element 29 is pressed against the axial bearing surface 32.

Furthermore, the support element 29 is fixed to the internal portion 20 of the secondary flywheel 3 by means of a plurality of fixing members 33 circumferentially distributed around the axis X. The fixing members 33 are for example rivets each passing through two opposite orifices provided respectively in the axial bearing surface 32 of the secondary flywheel 3 and in the support element 29.

The support element 29 is formed from a metal sheet. The metal sheet is made of steel and has undergone a quenching heat treatment followed by tempering so as to give it the desired mechanical properties.

As shown in FIG. 4, each of the cam followers 28 is advantageously fixed on a lug 34 of the support element 29 extending radially outwards from a central body. Such an arrangement makes it possible to limit the inertia of the support element 29.

The cam followers 28 are here rollers 35 mounted mobile in rotation on the primary flywheel 2. In order to reduce parasitic friction likely to affect the damping function, the rollers 35 are advantageously mounted in rotation on the element of support 29 by means of rolling elements, such as balls, rollers or needles.

As shown in FIG. 1, the rollers 35 are each carried by a cylindrical rod 36 extending parallel to the axis of rotation X. The cylindrical rod 36 passes through an orifice formed in the support element 29 and is fixed by riveting. To do this, the cylindrical rod 36 comprises a flange 37 and a rivet head 38, deformed by riveting, which sandwich the support element 29. The rolling members cooperate, on the one hand, with a rolling track formed on the outer periphery of the cylindrical rod 36 and, on the other hand, with a raceway formed on the inner periphery of the roller 35. The rolling members are held axially in the rolling space by means of a collar 39 projecting radially outward from the rear end of the cylindrical rod 36 and a retaining ring 40 mounted on the cylindrical rod 36.

Furthermore, the inner periphery of the roller 35 has a front shoulder 41 and a rear shoulder 42 formed respectively on either side of the raceway formed on the inner periphery of the roller 35. The front shoulder 41 and the shoulder rear 42 cooperate respectively with the retaining ring 40 and the collar 39 so as to limit the axial movement of the roller 35 relative to the cylindrical rod 36.

As shown in FIG. 1, the annular portion 10 of the primary flywheel 2 comprises an external part 43 which is offset axially towards the rear. Thus, part of the cam followers 28 is disposed radially outside the internal part 17 of the primary flywheel 2, in a cavity defined by the external part 43 and the cylindrical skirt 11. Such an arrangement contributes to limiting the space requirement. axial of the double damping flywheel 1.

Furthermore, the drive ring 21 is fixed to a free edge 44 of the cylindrical skirt 11. As shown in FIG. 1, this free edge 44 extends forwards beyond the cam follower 28. This the free edge 44 is also offset radially inwards relative to the rest of the cylindrical skirt 11. The free edge 44 is offset radially beyond the outermost point of the cam follower

28. Such an arrangement makes it possible, for a set-up diameter of the drive crown 21, to increase the set-up diameter of the cam follower 28 and thus to increase the torque transmissible by the double damping flywheel 1.

In order to allow the mounting of the cam followers 28 in such a double damping flywheel 1, the primary flywheel 2 comprises for each of the cam followers 28 an opening 45 which has a diameter greater than that of the cam follower 28 and which is arranged for authorize the mounting of the cam follower 28 through the primary flywheel 2. Furthermore, as shown in FIG. 6, the primary flywheel 2 has a plurality of orifices 46 facing each of the fixing members 33 of the element support 29 on the secondary flywheel 3.

Also, for mounting such a double damping flywheel 1, the support element 29 is firstly presented opposite the primary flywheel 2 then the cam followers 28 are inserted through openings 45 formed in the primary flywheel 2 so that their cylindrical rod 36 is placed in the dedicated orifice of the support element 29. The rivet heads 38 are then deformed so as to secure the cam followers 28 to the support element

29. Subsequently, the secondary flywheel 3 is fixed to the support element 29 by means of dedicated fixing members 33, the orifices 46 formed in the primary flywheel 2 authorizing the riveting operations of said fixing members 33.

The double shock-absorbing flywheel 1 is further equipped with a friction assembly 47, in particular shown in FIG. 1, arranged to exert a friction-resistant torque during the relative rotation between the primary 2 and secondary flywheels 3. The assembly of friction 47 is thus able to dissipate by friction the energy accumulated in the flexible blades 23. The friction assembly 47 comprises a friction washer 48. The latter is held in abutment against the support element 29 by an elastic washer 49 which is integral in rotation with the primary flywheel 2. The elastic washer 49 is for example a metal washer of the "Belleville" washer type, while the friction washer 48 is preferably made of plastic.

Figures 7 to 9 illustrate a double damping flywheel 1 according to a second embodiment. This second embodiment differs from that described above in relation to FIGS. 1 to 6, on the one hand, by the structure of the friction assembly 47, and on the other hand, by the presence of a damper of torsion with oscillating mass of inertia supported by the support element 29. These two features have no connection between them and one and / or the other of these two features can be combined with the features described above.

The friction assembly 47 comprises a cover 51 which is fixed to the support element 29. The cover 51 is fixed to the support element 29 by a plurality of rivets, shown in FIG. 9. As shown in the figure 8, the cover 51 has an annular rim 53 which forms a bearing surface for an elastic washer 54. The elastic washer 54 thus exerts an axial force on a friction washer 55 so as to press it against the support element 29 Furthermore, the friction assembly 47 comprises a drive member 56 integral in rotation with the primary flywheel 2. To do this, the drive member 56 is for example riveted to the annular central body 24 for fixing the elastic members. damping 22, as shown in FIG. 7.

In relation to FIGS. 8 and 9, it can be seen that the drive member 56 comprises a plurality of radial fingers 57 which are each interposed with a determined circumferential clearance in a dedicated notch 58 which is formed in the friction washer 55. Thus, the friction washer 55 is rotated relative to the support member 29 so as to exert a friction resistant torque as soon as the circumferential play has been taken up.

Furthermore, as shown in FIG. 9, the double damping flywheel 1 is also equipped with a torsional damper with oscillating mass of inertia 50 of the pendulum damping type. The pendulum damper comprises a plurality of masses of inertia, also called pendulum weights 59, circumferentially distributed on the support element 29. The pendulum weights 59 are able to oscillate relative to the support element 29 in an orthogonal plane to the axis of rotation X, in response to irregularities in rotation.

The pendulum weights 59 have a general shape of an arc of a circle. Each pendulum weight 59 has two sides which extend axially on either side of the support element 29 and are axially connected to each other by means of two connecting spacers 60. To do this , each side has two cut-outs intended for fitting by force-fitting the connecting spacers 60. Furthermore, each connecting spacer 60 axially passes through an opening 61 made in the support element 29.

The oscillations of the pendulum weights 59 are guided by two rolling elements, not shown, which each cooperate with a first raceway carried by the pendulum weights 59 and with a second raceway, carried by the support element 29. The first rolling tracks are carried by the connecting spacer 60 connecting the sides of each pendulum flyweight 59 while the second rolling tracks are formed by the outer edge of the openings 61 for passage of the connecting spacers 60. The rolling element is, for example, formed by a cylindrical roller of circular section. The shapes of the raceways are arranged so that the pendulum weights 59 are tuned to an order taking a value close to the rank of the predominant harmonic vibrations generated by the motor. A motor operating with 2n cylinders mainly generating harmonics of rank n the pendulum damper must therefore be tuned to an order taking a value close to n in order to dampen the main vibrations.

FIG. 10 represents a double damping flywheel 1 according to a third embodiment. This embodiment differs from the second embodiment described above in relation to FIGS. 7 and 8 in that the drive ring 21 is fixed on the external periphery of the support element 29.

Figures 11 to 13 disclose a double damping flywheel 1 according to a fourth embodiment. This embodiment differs mainly from the embodiments described above by the structure of the primary 2 and secondary 3 flywheels. In this embodiment, the primary flywheel 2 comprises one or more flexible annular sheets 62 which are, on the one hand, fixed on an external annular mass of inertia 63 at their radially external edge, and, on the other hand, fixed to the annular central body 24 for fixing the elastic damping members 22. The starter ring 21 is fixed radially to the exterior of this external annular mass of inertia 63. The flexible annular sheet (s) 62 are fixed to the external annular mass of inertia 63 by a plurality of rivets 64 circumferentially distributed around the axis X. Furthermore, as shown in FIG. 11, the annular central body 24 is also fixed to the annular central body 24 for fixing the elastic damping members. ent 22 by riveting.

The secondary flywheel 3 has an internal hub which extends axially towards the rear from the internal portion of the secondary flywheel 3 and which supports a bearing 66 for guiding the secondary flywheel 3 in rotation, such as a rolling bearing.

The outer ring of the bearing 66 cooperates with an inner surface of the annular central body 24. Thus, in this embodiment, the fixing of the primary flywheel 2 on the driving shaft as well as the guiding in rotation of the primary flywheel 2 relative to the flywheel secondary 3 are provided by the annular central body 24 of the elastic damping members 22.

Although the invention has been described in connection with several particular embodiments, it is obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these are within the scope of the invention.

The use of the verb "behave", "understand" or "include" and its conjugate forms do not exclude the presence of other elements or steps than those set out in a claim.

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

Claims (19)

1. Double damping flywheel for a motor vehicle transmission chain comprising: - a primary flywheel (2) intended to be fixed to a shaft driving the transmission chain; - a secondary flywheel (3) intended to form a reaction plate for a clutch device; the primary flywheel (2) and the secondary flywheel (3) being rotatable relative to each other about an axis X; the secondary flywheel (3) comprising an internal portion (20) and an external portion (5) radially outside the internal portion (20), the external portion (5) having an annular friction surface (6) intended to cooperate with the clutch device; - an elastic damping member (22) for transmitting a torque and damping the rotation acyclisms between the primary flywheel (2) and the secondary flywheel (3); the elastic damping member (22) being integral in rotation with the primary flywheel (2) and comprising a cam (27) connected to the primary flywheel by an elastic connection, the cam cooperating with a cam follower (28); - the cam follower (28) being supported by a support element (29) which is fixed to the secondary flywheel (3); the support element (29) comprising a support portion (67) which is axially spaced from the external portion (5) of the secondary flywheel (3) and the cam follower (28) being carried by the support portion to thermally insulate it from the annular friction surface (6) of the secondary flywheel (3). 2. Double damping flywheel (1) according to claim 1, in which the support element (29) is fixed to the internal portion (20) of the secondary flywheel (3). 3. Double damping flywheel (1) according to claim 2, in which the external portion (5) of the secondary flywheel (3) is axially offset from the internal portion (20) of the secondary flywheel (3) in a direction opposite to the support element (29) so as to form at least part of a space (31) axially separating the external portion of the secondary flywheel (3) from the support portion (67). 4. Double damping flywheel (1) according to claim 2 or 3, in which the support element (29) has a central opening having an annular edge and in which the internal portion (20) of the secondary flywheel (3) has a shoulder providing a cylindrical bearing surface (30) cooperating with the annular edge of the central opening and an axial bearing surface (32) bearing against the support element (29). 5. Double damping flywheel (1) according to any one of claims 2 to 4, in which the support element (29) is fixed to the secondary flywheel (3) by a plurality of fastening members (23) passing through. each through an opening in the support element (29) and an opening in the internal portion of the secondary flywheel (3). 6. Double damping flywheel (1) according to any one of claims 1 to 5, in which the elastic damping member (22) comprises a plurality of cams (27) which are each connected to the primary flywheel (2) by an elastic link and each cooperate with a respective cam follower (28); each of the cam followers (28) being carried by the support portion (67). 7. Double damping flywheel (1) according to claim 6, in which each of the cam followers (28) is fixed on a lug (29) respective to the support portion (67) which extends radially outwards. 8. Double damping flywheel (1) according to any one of claims 1 to 7, comprising at least one fixing member (18) of the primary flywheel (2) to the driving shaft and in which the elastic transmission member ( 22) has a fixing portion which is connected to the cam (27) by the elastic link and which is fixed to the primary flywheel (2); said fixing portion being provided with an orifice (25) for passage of said fixing member (18) of the primary flywheel (2) to the driving shaft. 9. Double damping flywheel (1) according to claim 8, in which the fixing portion is an annular central body (24). 10. Double damping flywheel (1) according to claim 9, in which the internal portion of the secondary flywheel (3) comprises a hub (65) supporting a bearing (66); said bearing (66) supporting the annular central body (24) of the elastic damping member (22) so as to guide the primary flywheel (2) in rotation relative to the secondary flywheel (3). 11. Double damping flywheel (1) according to any one of claims 1 to 10, in which the primary flywheel (2) comprises an annular portion (10) of radial orientation provided with an external periphery and a cylindrical skirt (11 ) which is arranged radially outside the elastic damping member (22) and the cam follower (28) and extends axially towards the secondary flywheel (3) from the external periphery of the annular portion ( 10) to a free edge (44) of said cylindrical skirt (11) which extends axially beyond the cam follower (28); the free edge (44) of the cylindrical skirt (11) supporting a drive ring (21) and being offset radially inwards beyond the outermost point of the cam follower (28). 12. Double damping flywheel (1) according to claim 11, in which the annular portion of the primary flywheel (2) has an opening (45) which has a diameter greater than that of the cam follower (28) and which is arranged to allow mounting the cam follower (28) on the support element (29) through the primary flywheel (2). 13. Double damping flywheel (1) according to any one of claims 1 to 10, in which the drive ring (21) is fixed on the support element (29). 14. Double damping flywheel (1) according to any one of claims 1 to 13, in which the primary flywheel (2) comprises an annular portion (10) of radial orientation which comprises an internal part (17) and an external part (43); said external part (43) being axially offset with respect to the internal part (17) in a direction opposite to the secondary flywheel (3); a part of the cam follower (28) being arranged radially outside the internal part (17) of the annular portion (10) of the primary flywheel (2). 15. Double damping flywheel (1) according to claim 1 to 14, comprising a friction assembly (47) arranged to exert a friction resistant torque during a relative rotation between the primary (2) and secondary (3) flywheels, the friction assembly (47) having a friction washer (48, 55) pressed against the support member (29). 16. Double damping flywheel (1) according to claim 15, in which the friction assembly (47) further comprises an elastic washer (49) integral in rotation with the primary flywheel (2) and exerting an axial force on the washer. friction (48) so as to press it against the support element (29). 17. Double damping flywheel (1) according to claim 15, in which the friction assembly (47) further comprises: - a cover (51) which is mounted on the support element (29), - an elastic washer (54) which is supported on the cover (51) and exerts an axial force on the friction washer (55) so as to press it against the support element (29); and 5 - a drive member (56) integral in rotation with the primary flywheel (2) and capable of rotating the friction washer (55) relative to the support element (29) during a relative rotation between the primary flywheel (2) and the secondary flywheel (3). 18. Double damping flywheel (1) according to any one of 10 claims 1 to 17, wherein the support member (29) is formed from a heat treated metal sheet. 19. Double damping flywheel (1) according to any one of claims 1 to 18, in which the support element (29) does not support a torsional damper with oscillating mass of inertia. 1/8