FR3057928A1 - TORSION OSCILLATION DAMPING DEVICE - Google Patents

Abstract

Device for damping torsional oscillations, in particular for a clutch of a motor vehicle, said device comprising: - a support (12); a plurality of pendular bodies, each mounted oscillating on the support, arranged around an axis X of rotation of the support; a base (16) for fixing the support; a plurality of spacers (20) each having a support end and a base end respectively fixed to support (22) and base (26) attachment areas, respectively, on the support and the base, respectively; a weakening region (28) being provided on the support and / or the fixing base within 5 cm of the support and / or base fixing area respectively of said spacer.

Description

Technical area

The invention relates to a device for damping torsional oscillations, in particular for a clutch of a motor vehicle.

State of the art

A device for damping torsional oscillations, for example a double damping flywheel, is conventionally used to filter vibrations due to motor acyclisms. It can in particular be integrated into a clutch, a hydrodynamic torque converter or a dry or wet double clutch.

Conventionally, it comprises a pendulum damping device which comprises a support intended to be driven in rotation and several pendulum bodies mounted oscillating on the support, the movement of a pendulum body relative to the support being generally guided by two cooperating rolling members. with support tracks and pendulum body tracks. In the torsional oscillation damping device, the support of the pendulum damping device is fixed to a base, generally in the form of a sheet extending parallel to the support, by means of spacers.

In certain circumstances, for example when the driver abruptly takes his foot off the accelerator or when the ABS is triggered, for example when passing a speed bump, violent shocks are transmitted to the pendulum damping device. These shocks, which can reach several thousand N.m, can lead to the rupture of the pendulum damping device.

DE 10 2013 220113 discloses a device for damping torsional oscillations in which the support is fixed to a secondary flywheel by means of an axially flexible connecting piece, in particular by means of a piece of S section, in particular by means of an openwork part. This flexibility is obtained by placing the flexible element between two stiff elements. This flexibility contributes to axial flexibility.

In normal operation, however, this flexibility can affect the effectiveness of vibration damping. Furthermore, the deformation of the connecting piece of DE 10 2013 220113 takes place substantially exclusively in a plane comprising the axis of rotation. It is therefore not easy to adjust the flexibility of this connecting piece in the different directions of space.

Finally, in DE 10 2013 220113, the space constraints impose a radial offset between the areas for fixing the connecting piece to the support and to the base.

There is a need to at least partially resolve these problems.

An object of the invention is to meet this need.

Summary of the invention

To this end, the invention provides a device for damping torsional oscillations, in particular intended to be integrated in a transmission chain of a motor vehicle, in particular in a clutch, the device comprising:

a support ;

a plurality of pendulum bodies, each mounted to oscillate on the support, arranged around an axis X of rotation of the support; a base for fixing the support;

a plurality of spacers each having a support end and a base end fixed respectively to support and base fixing areas, respectively, to the support and the base, respectively;

a weakened region being provided on the support and / or the fixing base nearby, that is to say less than 5 cm, less than 3 cm, less than 2 cm, less than 1 cm, or even in contact with the support and / or base fixing area, respectively, of a said spacer.

The inventors have discovered that the presence of such a weakening region considerably reduces the risk of rupture in the event of extreme shock. In addition, advantageously, the provision of a weakened region on the support and / or the base can be carried out in many ways. In particular, the weakening region can be easily adapted as a function of the desired flexibility in the different directions of space.

The weakened region transforms flexion into torsion. This torsion is local at the level of the weakening zone and the axial stiffness of the device is hardly changed.

A device according to the invention can also include one or more of the following optional characteristics:

- the weakening region and the spacers are shaped so as to provide a connection having a stiffness of between 50 and 7000 N.m / °, in particular measured with respect to the axis of rotation of the support X.

- the weakening region is in the form of a window and / or a reduction in thickness and / or a local modification of the support or base material;

- The weakening region is shaped to promote rotation of the spacer around an axis intersecting with the axis X and passing through said spacer, preferably a radial axis relative to the axis X;

- A weakening region of the support and / or the base, preferably each of the weakening regions of the support and / or the base, has a window passing through the support and / or the base, respectively;

a weakening region near a support and / or base fixing zone of a spacer, preferably of any spacer, has two said windows extending symmetrically with respect to an axial plane, said windows windows preferably extending along a circular line centered on the axis of said spacer;

- A said window, preferably each window, extends between two adjacent spacers so as to constitute a weakening region for each of said spacers;

- Said window opens radially;

the weakening region extends parallel to the lateral surface of said spacer, said lateral surface preferably being cylindrical, preferably of circular section;

- The weakening region extends along a circular line whose axis coincides with the axis of said spacer;

- The weakening region has the form of one or more grooves, preferably circular, formed on one side, preferably on each side of the support and / or of the base;

- The weakening region is defined by an intermediate piece ensuring the mechanical connection between said spacer and the support or the base, said intermediate piece preferably being shaped so as to promote rotation of a spacer at least around an axis radial with respect to the X axis, the intermediate piece preferably being constituted by a substantially planar sheet;

- The intermediate piece is crimped on the spacer and / or the support and / or the base, or fixed by means of a rivet on said support and / or said base;

- Said intermediate piece, preferably in the form of a plate, is fixed at two points separated by a said fixing zone, preferably located at the same distance from the X axis;

a zone for fixing the support and / or the base, preferably each zone for fixing the support and / or the base is arranged on an island of material connected to a support and / or base base, respectively, by a material bridge, said material bridge preferably extending substantially radially with respect to the axis X;

- The material bridge has a thickness identical to that of the support base or the base to which it is connected;

- The material bridge extends radially outside the base base or radially inside the support base;

- The device comprises a spacer whose support and base fixing zones are arranged on said islands of respective material connected to the support and base bases, respectively, by bridges of support and base material, respectively, the ratio between the length of the support material bridge over the length of the base material bridge being between 0.5 and 10;

- The length / 20 of the spacer between the support and the base, measured along the axis X, is greater than the thickness of the base, the ratio l ₂ Q / eie being greater than two and less than ten;

- the weakening regions formed on the support are all the same and / or the weakening regions formed on the base are all the same, and / or all the weakening regions are the same.

The device for damping torsional oscillations according to the invention is preferably chosen from a double damping flywheel, a hydrodynamic torque converter and a friction disc.

The invention also relates to a motor vehicle equipped with a device for damping torsional oscillations according to the invention.

Brief description of the figures

Other characteristics and advantages of the invention will become apparent on reading the detailed description and on examining the appended drawing in which:

- Figure 1 shows, schematically, the deformation of a damping device in the prior art (fig. la) and a device according to the invention (fig. lb);

- Figures 2 to 8 show, schematically, sections illustrating different embodiments for a weakening region.

In the various figures, identical references are used to designate identical or analogous members.

Definitions

Unless otherwise stated,

- axially means parallel to the axis X of rotation of the support,

- Radially means along a transverse axis intersecting the axis of rotation of the support;

- transverse means in a plane perpendicular to the axis of rotation of the support,

- angularly or circumferentially mean around the axis of rotation of the support,

- orthoradialement means perpendicular to a radial direction and in a transverse plane.

By radial plane is meant a plane containing a radial axis and the X axis.

By axial plane is meant a plane containing the X axis.

By radial offset, reference is made to the positions of two members which are not at the same distance from the X axis.

The diameter of a section is equivalent to the diameter of a disc having the same surface as said section. When the section is discoidal, the equivalent diameter is therefore equal to the diameter of the section.

The rest position of a pendulum body is the position adopted by the pendulum body when it is subjected to a centrifugal force resulting from the rotation of the support, without being subjected to torsional oscillations coming from acyclisms of the heat engine. The pendulum bodies shown are in their rest positions.

The thickness of a part refers to a dimension measured along the X axis.

By motor vehicle is meant not only passenger vehicles, but also industrial vehicles, which notably includes heavy goods vehicles, public transport vehicles or agricultural vehicles.

Unless otherwise indicated, the verbs to include, present or understand must be interpreted broadly, that is to say without limitation.

detailed description

As shown in FIG. 2, a pendulum damping device 10 according to the invention comprises a support 12 able to move in rotation around an axis X and a plurality of pendular bodies 14 movable relative to the support 10. The bodies pendulars are preferably distributed equiangularly around the axis X. Preferably, their number is greater than two and / or less than eight. The device can in particular comprise three or six pendulum bodies. In the example shown, the device comprises six pendular bodies uniformly distributed around the axis X. The support 12 has a generally planar, annular shape.

Each pendulum body 14 conventionally comprises first and second pendulum masses, of generally planar shape, extending respectively opposite the first and second large support faces 12. Conventionally, the pendulum masses are matched by means of connecting members, again called sprains. Each pendulum body is mounted oscillating on the support, by means of rolling members, conventionally rollers, which pass through rolling windows made in the thickness of the support. Conventionally, each rolling member cooperates on the one hand with a first rolling track defined by the outline of one of the windows and, on the other hand, with a second rolling track defined by the pendular body, more precisely defined by the outline of a pendulum masses connecting member. In a variant not shown, each rolling member cooperates with a first rolling track defined by the outline of a window made in the support and, on the other hand, with two second rolling tracks, axially framing the first rolling track , each defined by one of the first and second pendulum masses. In a variant not yet shown, the support can be in two parts and the pendulum bodies are arranged axially between these two parts.

All known means for authorizing an oscillation of a pendulum body on the support can be implemented.

As shown in FIG. 1, the support 12 is conventionally rigidly linked to a base 16, by means of spacers 20.

The base 16 is preferably chosen from a web, a guide washer or a phasing washer from a double damping flywheel or from a hydrodynamic torque converter or from a friction disc.

Conventionally, the base 16 has a substantially planar shape, extending substantially transversely to the axis X of the support. The support and the base are therefore substantially parallel to each other and spaced from each other by a constant distance, defined by the useful length / 20 of the spacer 20.

In a preferred embodiment, the length / 20 of the spacer between the support 12 and the base 16, measured along the axis X, is greater than the thickness of the base. Preferably, the ratio / 2 (/ 2/6 is greater than 2, preferably greater than 3, preferably greater than 4 and / or preferably less than 10, preferably less than 8, preferably less than 6, a ratio of 5 being considered optimal, in particular between the axial size and the flexibility provided.

The length / 20 is preferably greater than 0.5 cm, preferably greater than 1 cm and / or preferably less than 5 cm. In particular, when is between 3 and 6 mm, preferably between 4 and 5 mm, then / 20 is between 15 and 30 mm, preferably between 20 and 25 mm.

The spacer 20 extends, preferably axially, between a support fixing zone 22 and a base fixing zone 26 by which it is rigidly fixed on the support and on the base, respectively. Between the support 12 and the base 16, the spacer has an equivalent diameter greater than 5 mm and / or less than 15 mm.

In a preferred embodiment, as shown, the cross section of the spacer is substantially constant between the support 12 and the base 16, preferably discoid.

The spacer is preferably made of steel. More preferably, the spacer has a resistance to torsion around its axis Y greater than the stiffness of the weakening zone.

The shape of the spacer 20 is not limiting.

The number of spacers 20 is preferably greater than 2 and / or preferably less than 8, preferably less than 6, preferably less than 4.

The spacers 20 are preferably distributed equiangularly around the axis X.

More preferably, the support attachment zones are radially closer to the X axis than the pendulum bodies.

The spacers can be fixed by any known means on the support and on the base. Preferably, they are fixed by riveting or crimping.

According to the invention, a weakening region 28 is provided in the vicinity of the support and / or base attachment area, preferably in the vicinity of the support attachment area and the base attachment area.

The weakened region is preferably in the form of a reduction in thickness and / or a window and / or a local modification of a support or base material.

Preferably, all of the weakened regions of the support are identical.

Preferably, all the weakening regions of the base are identical.

Preferably, all the weakening regions of the support and of the base are identical.

A weakening region 28 around a support fixing area may be the same or different from a weakening region near a basic fixing area. For the sake of clarity, only embodiments of weakening regions formed around a support fixing zone are described below. All of these embodiments are however applicable for the weakening regions formed around the basic fixing zones.

The weakening region is preferably configured so as to ensure a stiffness greater than 50 N.m / ° and preferably less than 6500 N.m / °.

In particular, when the device is intended for a Diesel vehicle, the weakening region is preferably configured so as to ensure a connection stiffness of between 50 and 4000 N.m / °, preferably less than 3000 N.m / °.

In particular, when the device is intended for an industrial vehicle, the weakening region is preferably configured so as to ensure a stiffness of connection with the spacer greater than 500 and less than 1500 N.m / °.

The stiffness values presented just above are overall stiffness values of the weakening regions and spacers, stiffness values measured in relation to the rotation tax of the support X.

As shown in FIGS. 4 to 8, the weakening region may include a reduction in thickness of the support, preferably all around the area for fixing the support. More preferably, the thinned region extends to the spacer and, more preferably, cooperates with the spacer in order to secure it (Figures 4 to 6).

The thinned region can be of constant or variable thickness, depending on the desired bending capacity in the different directions.

As shown in FIGS. 4 to 8, a thinned region may be of constant thickness along a circle centered on the axis Y of the spacer, preferably regardless of the circle considered.

In the embodiment of FIG. 7, the weakening region has concentric grooves 30, centered on Tax Y. The grooves can be formed on one or on the two large faces of the support.

Preferably, the minimum thickness in the weakening region is less than 80%, preferably less than 60%, or even less than 50% of the thickness of the support.

The thinned region may be substantially annular, as shown in FIG. 8.

In the embodiment of Figures 4 to 6, the thinning is obtained by means of an intermediate piece 32 fixed on the one hand on the support and on the other hand on the spacer. The attachment of the intermediate piece to the support can in particular be obtained by extrusion or by riveting.

Preferably, the intermediate piece provides the mechanical junction between the support and the spacer. The intermediate piece 32 can have the shape of a cup, fixed all along its periphery on the support 12 and provided with a central orifice inserted in an annular groove 34 of the spacer, as shown in FIG. 5b. The intermediate piece can in particular be crimped.

The intermediate piece 32 can also take the form of an elongated plate, as shown in FIG. 6, preferably fixed at at least two points on the support, the fixing points of the plate being preferably diametrically opposite with respect to the support attachment area.

The weakening can also result from the use of an intermediate piece 32 made of a material different from that of the support, for example having greater flexibility. Local thinning can then be optional.

In a particularly advantageous embodiment, as shown in FIG. 3a, the weakening region comprises one or more windows 36.

In the embodiment of FIG. 1b, the weakening region 28 comprises two windows arranged symmetrically with respect to a radial plane P passing through the axis Y. Preferably, each window 36 extends over an angular sector a, around the Y axis, greater than 60 °, preferably greater than 80 ° and / or less than 170 °, preferably less than 150 °. Preferably, each window 36 extends in an arc centered on the axis Y. The width / 36 of a window 36 is preferably constant. The width of a window 36 is preferably greater than 2 mm, preferably greater than 3 mm and / or less than 15 mm, preferably less than 12 mm. The dimensions of the windows are not, however, limiting.

The shape of the window 36 is not limiting. In one embodiment, a window 36 formed on the support opens radially towards the inside of the support and / or a window 36 formed on the base opens radially towards the outside of the base.

In a particularly advantageous embodiment, as shown in FIG. 3, a window 36 extends between two adjacent spacers, thus constituting a weakening region for these two spacers.

FIG. 3 illustrates an example in which the adjacent spacers of any pair of adjacent spacers are separated from each other by a window opening radially, towards the X axis or away from the X axis depending on whether the window considered constitutes a region of weakening of the support or of the base, respectively.

In this embodiment, the windows 36 are so wide that only bridges of support material 38 remain between the support fixing zones and the radially outer annular part 40, called the support base, which carries the bodies. commuters (not shown).

Likewise, the windows 36 ′ which separate the base attachment zones lead to the creation of bridges of base material 38 ′ connecting the base attachment zones to the annular part, said radially inner base base 40 ′, of base 16.

The length / 33 of a bridge of support material is preferably greater than 3 and / or less than 30 mm.

The length Ζ ₃₈ 'of a base material bridge is preferably greater than 3 and / or less than 30 mm.

Preferably, as shown in FIG. 3c, the ratio between the length of a bridge of support material 38 over the length I38 · of a bridge of base material 38 'is greater than 0.5, preferably greater than 0.8 and / or less than 10, preferably less than 8, preferably less than 5, preferably less than 3, preferably less than 2, a ratio of 1 being preferred.

In the embodiment of FIG. 3, the support attachment zones and / or the base attachment zones each belong to an island (42, 42 ′) connected to the rest of the support and / or of the base, (base of support 40 and base 40 '), respectively, by a material bridge.

A bridge of support or base material preferably extends in the general plane of the support or base, respectively. Preferably, it extends substantially radially. More preferably, the island and / or the material bridge connecting the island to a base have a thickness identical to that of said base.

Preferably, the thickness of the base and / or of the island is less than 10 mm, preferably less than 6 mm and more than 2 mm, preferably more than 3.5 mm.

Preferably, the width of a material bridge is greater than 3 mm, preferably 5 mm and less than 30 mm, preferably less than 25 mm. Preferably, the island and / or the material bridge came integrally with said base.

The material bridge can also be qualified as a torsion beam.

Tests have shown that the presence of weakening regions, preferably for each of the support and base attachment zones, significantly improves impact resistance. In addition, the weakened regions can have various shapes, which allows them to be precisely adapted to their environment.

Of course, the combinations of the various embodiments described above are possible.

Claims (15)

1. A device for damping torsional oscillations, in particular for a clutch of a motor vehicle, said device comprising: - a support (12); - A plurality of pendulum bodies, each mounted to oscillate on the support, arranged around an axis X of rotation of the support; - a base (16) for fixing the support; - a plurality of spacers (20) each having a support end and a base end fixed respectively on support (22) and base (26) fixing zones, respectively, on the support and the base, respectively; a weakening region (28) being provided on the support and / or the fixing base within 5 cm of the support and / or base fixing zone respectively of a said spacer. 2. Device according to the preceding claim, wherein the weakening region and the spacers are shaped so as to provide a connection having a stiffness between 50 and 7000 N.m / °. 3. Device according to any one of the preceding claims, in which the weakening region is in the form of a window and / or a reduction in thickness and / or a local modification of the support material. or from the base. 4. Device according to any one of the preceding claims, in which the weakening region is shaped to favor a rotation of the spacer around an axis intersecting with the axis X and passing through said spacer, preferably an axis. radial with respect to the X axis. 5. Device according to any one of the preceding claims, in which a weakened region of the support and / or of the base, preferably each of the weakened regions of the support and / or of the base, has a window (36 ) passing through the support and / or the base, respectively. 6. Device according to the immediately preceding claim, wherein said weakening region has two said windows extending symmetrically with respect to a plane containing the axis X, said windows preferably extending along a centered circular line. on the axis (Y) of said spacer. 7. Device according to any one of the two immediately preceding claims, in which each window extends between two adjacent spacers so as to constitute a weakening region for each of said spacers. 8. Device according to the immediately preceding claim, wherein said window opens radially. 9. Device according to any one of the preceding claims, in which the weakening region extends parallel to the lateral surface of said spacer. 10. Device according to any one of the preceding claims, in which the weakening region has the form of one or more grooves (30). 11. Device according to any one of the preceding claims, in which the weakening region is defined by an intermediate part (32) ensuring the mechanical connection between said spacer and the support or the base. 12. Device according to any one of the preceding claims, in which a zone for fixing the support and / or the base is disposed on an island of material connected to a support and / or base base, respectively, by a bridge. matter. 13. Device according to the immediately preceding claim, comprising a spacer, the support and base fixing zones of which are disposed on islands of respective material connected to support and base bases, respectively, by bridges of support material and base, respectively, the ratio between the length of the support material bridge over the length of the base material bridge being between 0.5 and 10. 14. Device according to any one of the preceding claims, in which the length / 20 of the portion of said spacer included between the support and the base, measured along the axis X, is greater than the thickness eie of the base, the ratio / 20 / ^ 70 being greater than 2 and less than 10. 15. Device according to any one of the preceding claims, in which the weakening regions formed on the support are all the same and / or the weakening regions formed on the base are all the same, and / or all the regions are the same.