CN112105838B - Torsional damper device with main damper and auxiliary damper - Google Patents

Abstract

A torsional damping device for a vehicle drive train, comprising: a first rotational element (7) for transmitting torque; a second rotational element (9 a,9 b) for transmitting torque; at least one damping module (M1, M2) comprising main dampers arranged between a first and a second rotary element, each main damper comprising a set of springs comprising a first spring (13-1) and a second spring (13-2) arranged in series by means of a phasing member (15), the first and second springs being provided between the first and the phasing element and between the phasing element and the second rotary element, respectively, the first and second springs, when deformed, allowing a relative rotation between the first and the second rotary element about a rotation axis (X).

Description

Torsional damper device with main damper and auxiliary damper

Technical Field

The present invention relates to the field of torque transmission in automotive devices and to a torsional damping device for a vehicle drive train.

Background

Motor vehicles usually have torsional damping devices which can be integrated in individual components of the drive train, for example a dual mass flywheel or a clutch disk. The torque limiter may also be associated with a torsional damping device to filter engine non-periodic (acyclism) and other torsional vibrations. The filtering is typically performed by one or more torsional damping modules, which are combined torsional dampers that operate in torsion and allow relative rotation of the first rotational torque transfer element with respect to the second rotational torque transfer element during transfer of torque. The spring may allow relative rotation and damping may be achieved by a friction device provided with a friction washer axially loaded by the spring washer, thereby dissipating some of the energy accumulated in the spring by friction.

In designing such torsional damping devices, particular attention is paid to the selection, size and arrangement of the springs to obtain a characteristic curve suitable for a particular application.

Disclosure of Invention

The object of the present invention is to improve the torsion damping devices of the prior art by proposing a device with an adjustable characteristic curve.

In particular, it is an object of the invention to make the angular stiffness of the damping device exceed a predetermined angular displacement threshold. In particular, it is an object of the invention to make the angular stiffness of the damping device exceed a predetermined angular displacement threshold.

To this end, the invention relates to a torsional damping device for a vehicle drive chain, comprising:

-a first rotational element for transmitting torque;

-a second rotational element for transmitting torque;

-at least one damping module comprising main dampers arranged between a first and a second rotary element, each main damper comprising a set of springs comprising a first and a second spring arranged in series by means of a phasing member, the first and second springs being provided between the first and the phasing member and between the phasing member and the second rotary element, respectively, the first and the second springs allowing, when deformed, a relative rotation between the first and the second rotary element about the rotation axis.

Each damping module comprises an additional spring carried by a phasing member, the torsional damping device being configured such that, in a first relative direction of rotation of the first rotary element with respect to the second rotary element from a relative angular position of repose adopted by the first and second rotary elements (at which no speed or torque is applied):

-when the angular displacement between the first and second rotary elements is less than a first angular displacement threshold between the first and second rotary elements, the additional spring is at a distance from the first rotary element such that no additional torque can be transmitted between the phasing member and the first rotary element by the additional spring, and

when the angular displacement between the first and second rotary elements is greater than or equal to the first angular displacement threshold, the additional spring bears directly or indirectly against the first rotary element, so that an additional torque can be transmitted between the phasing member and the first rotary element by the additional spring.

Here and in the rest of the text, the expression "directly and indirectly" or "directly or indirectly" is used because an interface element such as a seat may be used between the first or second rotating element or the phasing member and the spring.

The expression "relative direction of rotation" is used to define the relative rotation of the first rotational element with respect to the second rotational element.

The damping device may further comprise one or more of the following features:

-each additional spring is a helical spring comprising:

-a first bearing surface arranged to bear directly or indirectly against the phasing member, and

a second bearing surface capable of bearing directly or indirectly against the first actuating surface of the first rotary element when the angular displacement between the first rotary element and the second rotary element in the first relative rotational direction is greater than or equal to a first angular displacement threshold.

The torsional damping means is arranged such that each second spring stops being compressed when the angular displacement in the first relative rotational direction from the relative angle of repose position between the first and second rotational elements is greater than or equal to a second angular displacement threshold between the first and second rotational elements. Thus, the deactivation of each second spring makes it possible to increase the stiffness of the damping means beyond a second predetermined angular displacement threshold.

According to one embodiment, the torsional damping means comprise a first stop carried by said phasing member and arranged to interact with a second stop carried by the second rotating element when the angular displacement in the first relative direction of rotation, from the relative rest angular position, between said first rotating element and said second rotating element is greater than or equal to a second threshold value of angular displacement between the first rotating element and the second rotating element. Thus, bringing the first stop into contact with the second stop makes it possible to stop the compression of the second spring by directly transmitting the torque between the first stop of the phasing member and the second stop of the second rotating element, thus increasing the stiffness of the damping device.

As a variant, each second spring is configured to be compressed to its maximum value and its turns are abutting when the angular displacement between the first and second rotary elements is greater than or equal to a second angular displacement threshold between the first and second rotary elements.

-the torsional damping device has an angular position of maximum angular displacement when the angular displacement between the first rotational element and the second rotational element in a first relative rotational direction of the first rotational element with respect to the second rotational element from the relative angular rest position reaches a third angular displacement threshold between the first rotational element and the second rotational element. In other words, when the torque transmitted is greater than the torque that produces the angular displacement equal to the third threshold, there is no longer damping of the torque.

The third threshold value may be obtained by a stop and/or may correspond to a maximum compression of the spring.

Thus, in the damping phase obtained in the first relative rotation direction, and when the angular displacement between the first rotary element and the second rotary element with respect to said relative angle of repose position is greater than zero and less than the first threshold value A1, each additional spring is not stressed and damping can be obtained by:

-damping, if required, is obtained by means of a first spring and a second spring in each set of springs,

damping is obtained only by the first spring of each group if the first and second stops have been supported, or the second spring of each group is compressed to the maximum (the turns are abutting).

Then, in a damping phase subsequently obtained when the angular displacement between the first and second rotary elements in the first relative rotary direction is greater than said first threshold value, said second bearing surface and the first actuating surface of said first rotary element bear against each other so that said additional spring is compressed parallel to said first spring.

There are actually three possible options:

the first and second thresholds are substantially equal and the damping curve has generally two slopes, the first slope corresponding to the compression of the first and second springs in series and the second slope corresponding to the compression of each first spring and each additional spring in parallel. The second slope is then substantially greater than the first slope, since it corresponds both to the deactivation of each second spring by means of the first and second stop and to the compression of each additional spring in parallel with each first spring.

Or the first and second thresholds are different, the damping curve has generally three slopes, a first slope corresponding to the compression of each first spring and each second spring in series, and a third slope corresponding to the compression of each first spring and each additional spring in parallel. The second slope then corresponds to:

-a compression corresponding to each first spring only when the second threshold is lower than the first threshold; or

-when the second threshold is greater than the first threshold, each second spring being in series with the assembly formed by the first spring and the additional spring arranged in parallel, corresponding to the compression of each second spring.

A transition slope is thus obtained between a first slope with a "relatively low" stiffness and a third slope with a "relatively high" stiffness.

According to one embodiment, the first rotational element forms a torque input element (E) of the torsional damping device and the second rotational element forms a torque output element of the torsional damping device. Such elements of the damping device are referred to as input elements: torque from the engine enters the torsional damping device through this element. Such an element of the damping device is called an output element: through which the torque exits the torsional damping device and reaches the gearbox.

-alternatively, the first rotational element forms a torque output element (S) and the second rotational element forms a torque input element of the torsional damping device.

One of the first and second rotary elements is formed by two guide washers axially retaining the first and second springs of each set of springs; the other of the first and second rotary elements is formed by a web axially disposed between two guide washers. According to one embodiment, the second rotary element is formed by two guide washers axially retaining the first and second springs of each set of springs, and the first rotary element is formed by a web axially arranged between the two guide washers. As a variant, the first rotary element may be formed by two guide washers axially retaining the first and second springs of each set of springs, and the second rotary element may be formed by a web axially arranged between the two guide washers.

-each damping module has at least one pair of transmission plates carried by the phasing members, each pair of transmission plates comprising a first transmission plate and a second transmission plate axially spaced from each other; each drive plate includes a first thrust zone that interacts directly or indirectly with the first end of the first spring and a second thrust zone that interacts directly or indirectly with the first end of the second spring, the first thrust zones of each pair of plates being axially spaced from each other and the second thrust zones of each pair of plates being axially spaced from each other. Thus, torque is transmitted between the phasing member and each set of springs, directly or indirectly, on the side areas of the faces of the first spring and of the first end of the second spring. The thrust zones of the plate are therefore arranged axially on either side of the geometric centre of the faces of the ends of the first and second springs. Therefore, the thrust polygon may be defined by the spacing between the first plate and the second plate, and the stability of the torque transmission by the phasing member may be improved.

The term "plate" is not limited to flat elements here, but in particular elements made of metal which are sufficiently thin to be deformable, in particular stamped.

The first and second drive plates of each pair are formed on first and second phasing washers, respectively, that are axially spaced from one another.

The additional spring of the damping module is arranged at least partially circumferentially between the first spring and the second spring of the damping module.

The first spring has a first central axis and the second spring has a second central axis, the intersection of the first central axis and the second central axis being located in the space occupied by the additional spring.

There is a plane perpendicular to the axis of rotation that passes through the first spring, the second spring and the additional spring.

The phasing member comprises at least one radially extending annular portion disposed radially inward of the first and second springs.

Each phasing washer includes a radially extending annular portion disposed radially inward of the first and second springs.

By arranging the annular portion radially inside (rather than outside) the first and second springs, the deformation of the annular portion is smaller. In addition, the inertia is small, which makes it possible to avoid resonance frequencies with harmful low frequencies.

The first spring and the second spring are arranged on substantially the same radius around the rotation axis. In other words, they are arranged in series on the same circular path.

The stiffness of the first spring is in the range of 50% to 150% of the stiffness of the second spring.

The volume occupied by the first spring is in the range of 50% to 150% of the volume occupied by the second spring.

Two phasing washers are fixed to each other axially spaced from each other. In particular, the two phasing washers are fixed to each other by means of spacers, each spacer having a first end crimped on one of the phasing washers and a second end crimped on the other of the phasing washers.

Two phasing washers are arranged on both sides of the web.

The second rotating element has two guide washers, which are axially arranged on either side of the phasing member.

Each damping module comprises a transmission head carried by the phasing member and arranged circumferentially between a first spring and a second spring of the spring group of the damping module, each transmission head comprising a housing in which the additional spring of the damping module is housed, so as to transmit an additional torque between the phasing member and the first rotary element when the angular displacement between the first rotary element and the second rotary element in the first relative rotational direction is greater than or equal to a first angular displacement threshold.

For each damping module, the transmission head is formed by a pair of transmission plates, the first and second transmission plates each comprising a hole, the holes in the first and second transmission plates being axially arranged facing each other so as to accommodate the additional spring of the corresponding damping module.

Each drive head further comprises two axial retaining elements for axially retaining the associated additional spring, the two axial retaining elements for the additional spring being arranged axially on both sides of the additional spring.

Each axial retaining element for retaining an additional spring is formed by a retaining tab bent in a direction having a radial component, the retaining tab being formed in one of the first and second transmission plates of the transmission head.

Each drive head therefore comprises two axial retaining elements, which are arranged axially on both sides of the additional spring associated with the drive head. Thus, the phasing member also ensures axial guidance of each additional spring.

-each axial retention tab protrudes with a radial component from the edge of the hole in the first or second drive plate having said retention tab. In particular, the retention tab protrudes from the lower radial edge of the hole. In other words, the profile of the retention tab defines a portion of the profile of the aperture before the retention tab is bent.

-each drive plate comprises a first radial retaining element arranged to retain the first spring associated with the drive plate radially with respect to the centrifugal force and a second radial retaining element arranged to retain the second spring associated with the drive plate radially with respect to the centrifugal force.

The first and second radial retaining elements of each drive plate are arranged circumferentially on either side of the associated additional spring in the circumferential extension of the associated additional spring.

The first radial retaining element is a first finger extending circumferentially radially outside the first spring.

The second radial retaining element is a second finger extending circumferentially radially outside the second spring.

On each plate, a first finger protrudes from the outer radial end of the first thrust zone and extends circumferentially.

On each plate, a second finger protrudes from the outer radial end of the second thrust zone and extends circumferentially.

Each additional spring is prestressed in its housing, if necessary.

Each additional spring is arranged circumferentially between the first spring and the second spring of the associated damping module.

The volumes of the first and second springs of each damping module are inscribed in a ring, and at least a part of the associated additional spring is also located in the ring. Thus, a radially compact damping device may be provided.

The first and second springs of the damping module extend along first and second axes, respectively, which are substantially inscribed in an implantation plane perpendicular to the rotation axis X, and the additional spring associated with the damping module extends along a third axis, which is also substantially inscribed in the implantation plane. Thus, an axially compact damping device may be provided.

Each additional spring has, in a plane perpendicular to axis X, a first internal corner facing a first spring of the module associated with said additional spring and a second internal corner facing a second spring of the module associated with said additional spring, the first and second internal corners being arranged circumferentially in the plane between a face of a first end of the first spring and a face of a first end of the second spring interacting with the phasing member.

Each phasing washer has an annular portion, and each plate is connected to the annular portion of the phasing washer by a radial arm.

-the first thrust zone of each plate is formed by the first wall of said plate and the second thrust zone of each plate is formed by the second wall of said plate.

The inclination of the first wall and the inclination of the second wall of the same plate are such that, in a plane perpendicular to the axis X passing through the first and second walls, the line of intersection of the first wall and said plane intersects the line of intersection of the second wall and said plane between the associated additional spring and the axis of rotation X.

For example, the angular stiffness of the additional spring is at least twice the angular stiffness of the stiffer of the first and second springs. For example, the angular stiffness of the first spring may be 10 Nm/DEG, plus or minus 50%, the angular stiffness of DR2 may be 15 Nm/DEG, plus or minus 50%, and the angular stiffness of the additional spring may be 30 Nm/DEG, plus or minus 50%.

For each set of springs, the first rotary element comprises a main opening able to accommodate a first spring and a second spring.

For each damping module, the first rotating element comprises a cavity capable of allowing a circumferential movement of the additional spring with respect to the first rotating element, the first actuation surface 40 forming one of the circumferential ends of the cavity.

The main opening and the cavity associated with the same damping module are formed in the same window of the first rotary element.

The first rotary element has a first bearing surface arranged to interact with a second end of the first spring opposite to the first end of the first spring and a second bearing surface arranged to interact with a second end of the second spring opposite to the first end of the second spring.

The guide washer of the second rotary element is formed from sheet metal, and for each spring group, each guide washer of the second rotary element has a stamped portion arranged to partially house and axially guide a first spring and a second spring of the group of springs.

For each set of springs, each guide washer has a third bearing surface arranged to interact with the second end of the first spring and a fourth bearing surface arranged to interact with the second end of the second spring.

The first stop is located on the periphery of the phase element.

The first and/or second transmission plate of the phasing member has a lug forming a first stop b1. The lugs extend axially to radially cover the radially outer edge of the second rotating element.

The lug is arranged radially above the additional spring.

A lip bent towards the lug connects the lug to the radially outer edge of the hole in each plate. The lip stiffens the plate radially outward of the hole.

The second stop is located on the periphery of the second rotating element.

The second stop is formed by a first tooth extending radially outwards from at least one of the guide washers.

Each drive head has a first stop.

The torsional damping means comprises a third stop carried by the first rotary element and arranged to interact with a fourth stop carried by the second rotary element when the angular displacement between the first and second rotary elements from said relative angular position in a first relative rotational direction of the first rotary element with respect to the second rotary element reaches a third angular displacement threshold between the first and second rotary elements.

The third stop is located on the periphery of the first rotating element.

The third stop is formed by a hook formed on the outer radial periphery of the web, which hook has an end region extending substantially axially, which is able to move circumferentially radially outside the outer radial edge of one of the guide washers 9a,9 b.

The third stop is arranged circumferentially between the two main openings in the first rotational element.

The fourth stop is located on the periphery of the second rotating element.

The fourth stop is formed by a second tooth extending radially outwards from the at least one guide washer.

The damping device has two damping modules.

The torsional damping device is configured such that, in a second relative rotational direction opposite to the first relative rotational direction, starting from a relative angle of repose position adopted by the first and second rotational elements (at which no speed or torque is applied) with respect to the second rotational element:

-each additional spring is at a distance from the first rotational element when the angular displacement between the first rotational element and the second rotational element is less than a fourth angular displacement threshold between the first rotational element and the second rotational element, and

each additional spring bears directly or indirectly against the first rotary element when the angular displacement between the first and second rotary elements is greater than or equal to the fourth angular displacement threshold, so that each additional spring can transmit an additional torque between the phasing member and the first rotary element.

In contrast, when the angular displacement between the first and second rotary elements is less than the fourth angular displacement threshold, no additional spring transmits an additional torque between the phasing member and the first rotary element.

The second bearing surface of each additional spring is arranged to bear directly or indirectly against the phasing member, and the first bearing surface is able to bear directly or indirectly against the second actuation surface of the first rotational element when the angular displacement between the first rotational element and the second rotational element in the second relative rotational direction is greater than or equal to a fourth angular displacement threshold.

The second bearing surface of each additional spring is arranged to bear directly or indirectly against a second circumferential edge of the hole in the first and second transmission plates associated with said additional spring, the second circumferential edge being opposite to the first circumferential edge.

The torsional damping means are arranged such that each second spring stops being compressed when an angular displacement between the first and second rotational elements in the second relative rotational direction from the relative angular position of repose is greater than or equal to a fifth angular displacement threshold between the first and second rotational elements. The deactivation of the second spring thus makes it possible to increase the stiffness of the damping means in this second relative rotational direction beyond a fifth predetermined angular displacement threshold.

A fifth stop is carried by the phasing member and is arranged to interact with a sixth stop carried by the second rotary element when the angular displacement between the first and second rotary elements in the second relative rotational direction reaches a fifth displacement threshold. Thus, bringing the fifth stop into contact with the sixth stop makes it possible to stop the compression of the second spring by directly transmitting torque between the fifth stop of the phasing member and the sixth stop of the second rotating element, thereby increasing the stiffness of the damping device.

The fifth stop is also formed on the lug forming the first stop.

The first stop and the fifth stop are formed on two circumferentially opposite edges of the lug.

Forming a sixth stop on the second tooth, the second tooth also forming a fourth stop.

The fourth stop and the sixth stop are formed on two circumferentially opposite edges of the second tooth.

-the torsional damping device has an angular position of maximum angular displacement when an angular displacement between the first rotary element and the second rotary element from the relative angular position in a second relative rotational direction of the first rotary element with respect to the second rotary element reaches a hexagonal displacement threshold between the first rotary element and the second rotary element. In other words, for torques greater than the torque producing the angular displacement equal to the sixth threshold, there is no further damping of the torque.

The sixth threshold value may be obtained by a stop and/or may correspond to a maximum compression of the spring.

The additional springs are tightly mounted or sandwiched between the first circumferential edges of the holes in the first and second driving plates and their second circumferential edges. Each additional spring may be prestressed in its housing.

The torsional damping means comprise a seventh stop carried by the first rotary element and arranged to interact with an eighth stop carried by the second rotary element when an angular displacement between the first and second rotary elements from said relative angular position in a second relative rotational direction of the first rotary element with respect to the second rotary element reaches a hexagonal displacement threshold between the first and second rotary elements.

The seventh stop is formed on a hook which also forms the third stop.

The seventh stop and the third stop are formed on two circumferentially opposite edges of the hook.

The eighth stop is formed on the first tooth, which also forms the second stop.

The second bearing surface of each additional spring is arranged to bear directly or indirectly against the second circumferential edges of the holes in the first and second drive plates associated with said additional spring.

The first bearing seat is interposed between the first rotary element and the first spring of each damping module on the one hand, and the second rotary element and the first spring of each damping module on the other hand.

The second bearing seat is interposed between the first rotary element and the second spring of each damping module on the one hand, and between the second rotary element and the second spring of each damping module on the other hand.

The first bearing surface has a first recess arranged to receive a pivot shaft protruding from the first seat.

The second bearing surface has a second recess arranged to accommodate a pivot projecting from the second seat.

The third bearing surface has a third recess arranged to receive a pivot shaft projecting from the first seat.

The fourth bearing surface has a fourth recess arranged to accommodate a pivot projecting from the second seat.

The third bearing seat is interposed between the phasing member and the first spring of each damping module.

The fourth bearing seat is interposed between the phasing member and the second spring of each damping module.

The third seat has a front bearing surface interacting with the first end of the first spring.

The fourth seat has a front bearing surface interacting with the first end of the second spring.

According to one embodiment, the second and fourth bearing blocks are arranged in contact with each other when the angular displacement between the first and second rotary elements in the first relative rotational direction from said relative rest angular position is greater than or equal to a second threshold value of angular displacement between the first and second rotary elements. In other words, the first stop is formed on the fourth bearing and the second stop is formed on the second bearing.

Each bearing block has a cover arranged to radially retain the spring against which it bears against the centrifugal force.

The first stop is formed at the end of the cover of the fourth bearing and the second stop is formed at the end of the cover of the second bearing.

According to one embodiment, the two axial retention elements of each drive head are formed by eye-cup portions; the first and second drive plates associated with the corresponding drive module each include an eye-cup portion.

-forming two cuts on each plate, circumferentially on both sides of the portion of the plate intended to form the eye-cup portion.

If desired, at least one of the circumferential edges of the eye cup portion forms a first stop of the damping device. The eye cup portion is thus arranged to bear against the teeth of the second rotational element forming the second stop when the angular displacement between the first rotational element and the second rotational element from said relative angular position in a first relative rotational direction of the first rotational element relative to the second rotational element is greater than or equal to a second threshold value of angular displacement between the first rotational element and the second rotational element.

The other circumferential edge of the eye cup portion forms a fifth stop of the damping device.

The phasing member comprises circumferential guiding means for axially guiding the first spring and the second spring.

For example, each driving plate comprises a first centering member arranged inside the first end of the first spring and a second centering member arranged inside the first end of the second spring.

Thus, the first spring and the second spring can be axially guided.

Each centering member is a tongue formed in the sheet metal of the plate and bent into a C-shape.

The tongue of the first centering member forming the first drive plate and the tongue of the first centering member forming the second drive plate are arranged axially facing each other to form a centering tube for centering the first spring.

The tongue of the second centering member forming the first drive plate and the tongue of the second centering member forming the second drive plate are arranged axially facing each other to form a centering tube for centering the second spring.

One of the first and second rotary elements is rotatably coupled to the friction disc and the other of the first and second rotary elements is rotatably coupled to a hub capable of rotating the transmission input shaft.

The first rotational element is rotatably coupled to the friction disc and the second rotational element is rotatably coupled to a hub capable of rotating the gearbox input shaft.

The damping means also comprise friction means F intended to dissipate the energy of the spring and avoid oscillation phenomena. Preferably, the friction means are arranged to rub only in the reverse drive direction.

The invention also relates to a transmission system comprising a torque limiter comprising a friction disc and a damping device according to the previous characteristics, the friction disc being mounted in rotation integrally with one of the first and second rotating elements of the damping device.

The additional spring is arranged radially inside the friction disc.

According to another solution:

the third bearing block is mounted to pivot on the phasing member.

The fourth bearing block is mounted to pivot on the phasing member.

The third and fourth seats are mounted so as to be pivotable about the same pivot pin. Thus, the inclination of the third and fourth seats may be varied according to the torque transmitted by the damping means and according to the centrifugal force. Thus, the pivoting of the seat makes it possible to limit the friction at the first spring and the second spring.

The third and/or fourth bearing blocks 180 are mounted so as to pivot about a spacer for connecting two phasing washers, the spacer 116 forming the pivot pin of the blocks;

the third and fourth seats each have axially overlapping perforated connecting tabs, so that their apertures also overlap, the pivot pin being inserted both in the aperture in the connecting tab of the third seat and in the aperture in the connecting tab of the fourth seat.

The third seat has a back-side bearing surface interacting with the additional spring. The bearing surface is formed in the recess of the third seat.

The third seat is circumferentially interposed between the first spring and the additional spring.

The fourth seat has a back-side bearing surface interacting with the additional spring. The bearing surface is formed in the recess of the fourth seat.

The fourth seat is circumferentially interposed between the second spring and the additional spring.

The additional spring is sandwiched between the third seat (via its first bearing surface) and the fourth seat (via its second bearing surface). Thus, when the additional springs are compressed, the support points of the springs on the pads are angularly close to each other. Thus, an additional stiffness increase may be obtained.

The third mount has a first stud arranged in a recess in the first drive plate, the end of the recess being able to limit the movement of the first stud and thus the pivoting of the third mount.

The third seat has a second cylinder pin arranged in a recess of the second transmission plate, the end of the recess being able to limit the movement of the second cylinder pin and thus the pivoting of the third seat.

The fourth mount has a first stud arranged in a recess in the first transmission plate, the end of the recess being able to limit the movement of the first stud and thus the pivoting of the fourth mount.

The third seat has a second cylinder pin arranged in a recess of the second transmission plate, the end of the recess being able to limit the movement of the second cylinder pin and thus the pivoting of the fourth seat.

Drawings

Preferred embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

FIGS. 1 and 2 are block diagrams illustrating the operational principles of the present invention;

FIG. 3 is an exploded view of the first embodiment;

FIG. 4 is a perspective view of the first embodiment;

fig. 5 is a perspective view of the first embodiment, wherein the guide washer of the second rotating element is not shown;

FIGS. 6 and 7 are sectional views of the first embodiment;

fig. 8 is a graph showing three characteristic damping curves corresponding to three modified embodiments of the first embodiment;

FIGS. 9 and 10 are detailed perspective views of a second embodiment having two different stages of angular displacement;

fig. 11 and 12 are perspective views showing a phasing member of another solution;

fig. 13 is a perspective view of a phasing member according to a third embodiment;

fig. 14 is a perspective view of a damping device according to a third embodiment.

Detailed Description

Fig. 1 and 2 show two block diagrams illustrating a torsional damping device for a vehicle drive train, comprising:

a first rotating element 7 for transmitting torque;

a second rotating element 9 for transmitting torque;

a damping module comprising main dampers a arranged between the first and second rotary elements 7, 9, each main damper a comprising a set of springs comprising a first spring 13-1 and a second spring 13-2 arranged in series by means of a phasing member 15, the first and second springs 13-1, 13-2 being respectively provided between the first and second rotary elements 7, 15 and between the phasing member 15 and the second rotary element 9, the first and second springs 13-1, 13-2, when deformed, allowing a relative rotation between the first and second rotary elements 7, 9 about the rotation axis X.

Each damping module comprises an additional spring 25 carried by the phasing member 15, the torsional damping device being configured such that, in a first relative direction of rotation of the first rotary element 7 with respect to the second rotary element 9 from a relative angular position of repose adopted by the first and second rotary elements 7 and 9 (at which relative angular position of repose no speed or torque is applied):

when the angular displacement between first rotating element 7 and second rotating element 9 is less than a first threshold value of angular displacement A1 between first rotating element 7 and second rotating element 9, additional spring 25 is at a distance from first rotating element 7 such that no additional torque can be transmitted between phasing member 15 and the first rotating element by additional spring 25, and

when the angular displacement between first rotating element 7 and second rotating element 9 is greater than or equal to first angular displacement threshold A1, the additional spring bears directly or indirectly against first rotating element 7, so that an additional torque can be transmitted between phasing member 15 and first rotating element 7 by means of additional spring 25.

The torsional damping means are arranged such that each second spring 13-2 stops being compressed when the angular displacement between the first and second rotary elements 7, 9 from the relative rest angular position in a first relative rotational direction of the first rotary element 7 with respect to the second rotary element 9 is greater than or equal to a second angular displacement threshold A2 between the first and second rotary elements 7, 9.

To this end, the torsional damping device schematically illustrated comprises a first stop b1 carried by the phasing member 15, and the first stop b1 is arranged to interact with a second stop b2 carried by the second rotary element 9 when the angular displacement between the first rotary element 7 and said second rotary element 9 in the first relative direction of rotation, starting from the relative rest angular position, is greater than or equal to a second threshold value A2 of angular displacement between the first rotary element 7 and the second rotary element 9.

The torsional damping device also has an angular position of maximum angular displacement when the angular displacement between the first and second rotary elements 7, 9 in the first relative rotational direction from the relative angular position of repose reaches a third angular displacement threshold A3 between the first and second rotary elements 7, 9. In other words, when the torque transmitted is greater than the torque generating the angular displacement equal to the third threshold A3, there is no longer a damping of the torque.

To this end, the torsional damping device schematically shown comprises a third stop b3 carried by the first rotary element 7, and the third stop b3 is arranged to interact with a fourth stop b4 carried by the second rotary element 9 when the angular displacement in the first relative rotational direction from the relative rest angular position between the first rotary element 7 and the second rotary element 9 reaches a third angular displacement threshold A3 between the first rotary element 7 and the second rotary element 9.

In fig. 1, the torque input element of the damping device is the first rotational element 7, and the torque output element of the damping device is the second rotational element 9.

In fig. 2, the torque input element of the damping device is the second rotating element 9, and the torque output element of the damping device is the first rotating element 7.

As can be seen from fig. 1 and 2, the first threshold of angular displacement A1 is reached when the angular displacement between the first rotating element 7 and the phasing member 15 reaches the threshold A1', and the second threshold of angular displacement A2 is reached when the angular displacement between the phasing member 15 and the second rotating element reaches the threshold A2'.

In the description and in the claims, the terms "outer" and "inner" are used together with the orientations "axial" and "radial" to denote the elements of the damping device according to the definitions given in the description. The axis of rotation X defines the "axial" direction. The "radial" direction is perpendicular to the axis X. The "circumferential" orientation is orthogonal to the axis of rotation X and orthogonal to the radial direction. The terms "outer" and "inner" are used to define the relative position of one component with respect to the other component with respect to the axis of rotation X, the component close to said axis being therefore described as inner, on the contrary, the one radially located at the periphery as outer. Furthermore, the angles and angular sectors represented are defined relative to the axis of rotation X.

Fig. 3 to 7 show a first embodiment of the torsional damping device as schematically shown in fig. 1.

The torsional damping device is coupled to a friction disc 2 of a torque limiter intended, in normal operation, to transmit a torque by rotating about an axis X and to limit it to a certain value. The friction disc 2 has a backing disc to both sides of which two friction linings 3 are attached by means of a first set of rivets 4.

The friction disc 2 is fixed to a first rotary torque transmitting element, in this case constituted by a disc called "web" 7, by means of a second set of rivets 6.

In a transmission system, as shown in fig. 6 and 7, the friction disc 2 coupled with the damping device forms part of a torque limiter, the lining 3 of the friction disc is pressed against a support disc 88 by a pressure plate 86, the pressure plate 86 is elastically loaded by a spring such as a Belleville washer 87, and the support disc 88 is mounted rigidly fixed to the flywheel.

The hub 5 is fixed by means of a third set of rivets 8 to a second rotary torque-transmitting element, which in this case consists of a pair of discs called "guide washers" 9a,9 b. The first guide washer 9a is fixed against one side of the hub 5 and the second guide washer 9b is fixed against the opposite side of the hub 5. Two guide washers 9a and 9b axially retain the first and second springs of each set of springs, and the web 7 is axially disposed between the two guide washers 9a and 9 b.

The hub 5 has internal splines which are capable of interacting with external splines of a transmission shaft.

The two torsional damping modules M1 and M2 are interposed between the web 7 and the guide washers 9a,9b, so that the web 7 on the one hand and the guide washers 9a,9b on the other hand can be rotated relative to each other by compressing the two damping modules M1 and M2.

In operation, the flywheel rotates the friction disc 2 and therefore the web 7 rigidly fixed thereto. The web 7 compresses the damping module, which transmits the torque to the guide washers 9a,9b and thus to the hub 5 rigidly fixed thereto. By transmitting torque between the web 7 and the guide washers 9a,9b, the damping module filters out non-periodic and other undesirable torsional movements.

In each damping module, the additional spring 25 is a helical spring comprising:

a first bearing surface 25a arranged to bear directly or indirectly against the phasing member 25, and

a second bearing surface 25b capable of bearing directly or indirectly against the first actuating surface 40 of the web 7 when the angular displacement between the web 7 and the guide washers 9a,9b in the first relative rotational direction is greater than or equal to a first angular displacement threshold A1.

Each damping module has a pair of transmission plates 17a and 17b carried by the phasing member 15, each pair of transmission plates comprising a first transmission plate 17a and a second transmission plate 17b axially spaced from each other.

Each driving plate comprises a first thrust zone P1 interacting directly or indirectly with the first end 13-11 of the first spring 13-1 and a second thrust zone P2 interacting directly or indirectly with the first end 13-21 of the second spring 13-2, the first thrust zones of each pair of plates being axially spaced from each other and the second thrust zones of each pair of plates being axially spaced from each other. Thus, torque is transmitted between the phasing member and each set of springs, directly or indirectly, on the side areas of the faces of the first springs 13-1 and the first ends of the second springs 13-2. Thus, the thrust zones of the plates are arranged axially on either side of the geometric center of the faces of the first springs 13-1 and the first ends of the second springs 13-2. It is therefore possible to vary and in particular increase the thrust polygon of the spring according to the spacing between the first plate and the second plate and, in this way, to improve the stability of the torque transmitted by the phasing member.

The first and second drive plates 17a,17b of each pair are formed on first and second phasing washers 15a, 15b, respectively, which are axially spaced from each other. The two phasing washers 15a and 15b are fixed to each other by spacers 16, each spacer 16 having a first end crimped onto one of the phasing washers and a second end crimped onto the other one of the phasing washers.

Two phasing washers 15a and 15b are arranged on either side of the web 7, while two guide washers 9a and 9b are arranged axially on either side of the two phasing washers 15a and 15 b.

Each damping module M1, M2 comprises a drive head 17, which is interposed directly or indirectly between the first spring 13-1 and the second spring 13-2 of the spring set of the damping module. Each drive head 17 comprises a housing L in which an additional spring 25 of the damping module is accommodated.

Each pair of transmission plates 17a,17b forms a transmission head 17 of the phasing member 15, the first 17a and second 17b transmission plates of each pair comprising a hole 47a, 47b, the hole 47a in the first 17a and the hole 47b in the second 17b transmission plate being arranged axially facing each other in order to accommodate the additional spring 25 of the corresponding damping module M1, M2.

The first bearing surface 25a of each additional spring 25 is arranged to bear directly or indirectly against the first circumferential edge 47a1 of the hole 47 in the first transmission plate 17a and the first circumferential edge 47b1 of the hole 47b in the second transmission plate 17b.

Each drive head 17 further comprises two axial retaining elements 18a, 18b arranged axially on either side of an additional spring 25 associated with the drive head for axially retaining the additional spring 25.

Each axial retaining element 18a, 18b for retaining an additional spring is formed by a retaining tab 18a, 18b bent in a direction having a radial component, the retaining tab 18a, 18b being formed in one of the first and second transmission plates 17a,17b of the transmission head. Thus, the phasing member 15 also ensures the axial guidance of each additional spring 25.

Each axial retention tab 18a, 18b projects with a radial component from the lower radial edge of the hole 47a, 47b in the first or second transmission plate 17a,17b having said retention tab 18a, 18b. In other words, the profile of the retention tabs 18a, 18b defines a portion of the profile of the apertures 47a, 47b before the retention tabs 18a, 18b are bent.

Each driving plate 17a,17b comprises a first radial retaining element 19a, 19b and a second radial retaining element 20a, 20b, the first radial retaining element 19a, 19b being arranged to radially retain the associated first spring 13-1 with respect to the centrifugal force, and the second radial retaining element 20a, 20b being arranged to radially retain the associated second spring 13-2 with respect to the centrifugal force.

In particular, the first radial retaining element 19a, 19b and the second radial retaining element 20a, 20b of each driving plate are arranged circumferentially on either side of the associated additional spring 25, in the circumferential extension of the associated additional spring 25.

The first radial retaining elements 19a, 19b are formed by first fingers extending circumferentially radially outside the first spring 13-1. The second radial retaining elements 20a, 20b are formed by second fingers extending circumferentially on the radially outer side of the second spring 13-2.

On each plate 17a,17b, a first finger 19a, 19b projects from the outer radial end of the first thrust zone P1 and extends circumferentially. On each plate, a second finger 20a, 20b projects and extends from the outer radial end of the second thrust zone P2 in the circumferential direction in the opposite direction to the first finger.

According to one embodiment, each additional spring 25 is arranged circumferentially between the first and second spring of the associated damping module. The volumes of the first and second springs 13-1, 13-2 of each damping module M1, M2 are inscribed in a ring, and at least a part of the associated additional spring 25 is also located in the ring. Thus, a radially compact damping device may be provided.

The first and second springs 13-1, 13-2 of the damping module M1 extend along first and second axes, respectively, which are substantially inscribed in an implantation plane perpendicular to the rotation axis X, and the additional spring 25 of the damping module M1 extends along a third axis, which is also substantially inscribed in the implantation plane. Thus, an axially compact damping device may be provided. The axes of the springs of the second damping module M2 are inscribed substantially in the same implantation plane.

Each additional spring 25 has, in a plane perpendicular to the axis X, a first inner corner 253 facing a first spring of the module associated with said additional spring and a second inner corner 252 facing a second spring of the damping module associated with said additional spring, the first and second inner corners being arranged circumferentially in the plane between the first end 13-11 of the first spring 13-a and the first end 13-21 of the second spring 13-2 interacting with the phasing member 15.

As shown in fig. 3 and 5, each phasing washer 15a, 15b has an annular portion, and each plate 17a,17b is connected to the annular portion of the phasing washer 15a, 15b by a radial arm.

The first thrust zone of each plate is formed by the first wall P1 of said plate and the second thrust zone of each plate is formed by the second wall P2 of said plate. These walls correspond to edge portions of the first transfer plate 17a and the second transfer plate 17b. The inclination of the first wall P1 and the inclination of the second wall P2 of the same plate are such that, in a plane perpendicular to the axis X passing through the first wall P1 and the second wall P2, the intersection line of the first wall P1 and said plane intersects the intersection line of the second wall P2 and said plane between the associated additional spring 25 and the rotation axis X.

For each set of springs, the web 7 includes a primary opening 71 capable of receiving both the first spring 13-1 and the second spring 13-2. In addition, for each damping module M1, M2, the web 7 comprises a cavity 72 able to allow the circumferential movement of the additional spring 25 with respect to the web 7. The first actuating surface 40 forms one of the circumferential ends of the cavity 72. The main opening 71 and the cavity 72 associated with the same damping module M1, M2 are in this case formed in the same window of the web 7.

The web 7 has a first bearing surface 74 arranged to interact with a second end 13-12 of the first spring 13-1 opposite to the first end 13-11 of the first spring 13-1 and a second bearing surface 73 arranged to interact with a second end 13-22 of the second spring 13-2 opposite to the first end 13-21 of the second spring 13-2.

The guide washers 9a,9b are formed from sheet metal and for each spring set each guide washer 9a,9b has a stamped portion 91a, 91b arranged to partially receive and axially guide a first spring 13-1 and a second spring 13-2 of the set.

For each set of springs, each guide washer 9a,9b has a third bearing surface 94 arranged to interact with the second end 13-12 of the first spring 13-1 and a fourth bearing surface 93 arranged to interact with the second end 13-22 of the second spring 13-2.

For each set of springs, each guide washer 9a,9b has:

a first slot arranged between the stamped portion and the third bearing surface 94 to allow a portion of the second end 13-12 of the first spring 13-1 to pass through,

a second slot arranged between the stamped portion and the fourth bearing surface 93 to allow a portion of the second end 13-22 of the second spring 13-2 to pass through.

As can be seen in fig. 5, the first spring 13-1 and the second spring 13-2 are arranged substantially on the same radius around the rotation axis. In other words, they are arranged in series on the same circular path.

The additional spring 25 of the damping module is at least partially arranged circumferentially between the first spring 13-1 and the second spring 13-2 of the damping module. The first spring 13-1 has a first centre axis and the second spring 13-2 has a second centre axis, the intersection of the first and second centre axes being located in the space occupied by the additional spring 25.

Furthermore, there is a plane perpendicular to the rotation axis, which plane passes through the first spring 13-1, the second spring 13-2 and the additional spring 25.

It can also be seen that the phasing member comprises two radially extending annular portions, which are arranged radially inside the first spring 13-1 and the second spring 13-2. Each phasing washer includes a radially extending annular portion that is disposed radially inward of the first and second springs 13-1 and 13-2.

In this first embodiment, the first angular displacement threshold A1 is about 40 degrees and is substantially equal to the second angular displacement threshold A2. The angular stiffness of the additional spring 25 of each damping module is greater than the angular stiffness of the first spring 13-1 and greater than the angular stiffness of the second spring 13-2. In this case, the stiffness of each of the first springs 13-1 is about 10 Nm/deg., the stiffness of each of the second springs 13-2 is about 15 Nm/deg., and the stiffness of each of the additional springs is about 30 Nm/deg.

An example of a damping curve is shown in fig. 8. These curves show a variant embodiment before the displacement reaches the third angular displacement threshold. In these variations, there is no stop between the first rotational element and the second rotational element. Curve 1 shows a variant in which the first threshold value A1 is equal to the second threshold value A2. Curves 2 and 3 show the damping of the other two variants.

Curve 2: the second threshold A2 is greater than the first threshold A1,

curve 3: the second threshold A2 is smaller than the first threshold A1.

Thus, in curves 2 and 3, it can be seen that by adjusting the angular threshold of the stop, a transient damping slope can be obtained.

In the first embodiment shown in fig. 3 to 7, a first stop b1 is formed on the periphery of the phasing member 15 on each drive head. The first and second transmission plates 17a,17b of the phasing member 15 each have a lug 41 forming a first stop b1. The lugs 41 extend axially so as to each radially cover the radially outer edge of the guide washers 9a,9 b. Each lug 41 is arranged radially above the additional spring 25.

On each drive plate 17a,17b, a lip 159 bent towards the lug 41 connects the lug 41 to the radially outer edge of the hole 47a, 47b in the drive plate 17a,17 b. This lip 159 stiffens the plate radially outside the hole.

A second stop b2 is formed on the periphery of the two guide washers 9a,9 b. The second stop b2 is formed by a first tooth 42 extending radially outwards from the guide washers 9a,9 b.

The torsional damping means comprises a third stop b3 carried by the web 7, and the third stop b3 is arranged to interact with a fourth stop b4 carried by the second guide washer 9b when the angular displacement between the web 7 and the second guide washer 9b in the first relative rotational direction from the relative angular position reaches a third angular displacement threshold A3 between the web 7 and the second guide washer 9 b. The third stop b3 is made on the periphery of the web 7. The third stop b3 is formed by two hooks 43, each hook 43 having a substantially axially extending end zone which is circumferentially movable radially outside the outer radial edge of the second guide washer 9 b.

The third stop b3 is made circumferentially between two main openings 71 in the web 7.

The fourth stopper b4 is made on the outer periphery of the second guide washer 9 b. The fourth stop b4 is formed by two second teeth 44 extending radially outward from the second guide washer 9 b.

The above-described operating principle is equally valid in a transmission direction referred to as forward, i.e. the torque path from the engine to the vehicle gearbox or from the torque input element of the damping device to the torque output element, and in a transmission direction referred to as reverse, i.e. the torque path from the gearbox to the vehicle engine or from the torque output element of the damping device to the torque input element.

Thus, the torsional damping device is configured such that, in a second relative rotational direction of the web 7 relative to the guide washers 9a,9b, opposite to the first relative rotational direction, each additional spring 25 is at a distance from the web 7 when the angular displacement between the web 7 and the guide washers 9a,9b is less than a fourth angular displacement threshold A4 between the web 7 and the guide washers 9a,9b, from a relative angular position of repose assumed by the web 7 and the second rotational element 9, at which no speed or torque is applied. Therefore, when the angular displacement between the web 7 and the guide washers 9a,9b is less than the fourth angular displacement threshold A4, no additional spring 25 transmits torque between the phasing member 15 and the web 7.

When the angular displacement between the web 7 and the guide washers 9a,9b is greater than or equal to the fourth angular displacement threshold A4, each additional spring 25 bears directly or indirectly against the web 7, so that an additional torque can be transmitted between the phasing member 15 and the web 7 by each additional spring 25.

The torsional damping means is arranged such that each second spring 13-2 stops being compressed when the angular displacement in the second relative rotational direction from the relative rest angular position between the web 7 and the second rotational element 9 is greater than or equal to a fifth angular displacement threshold A5 between the web 7 and the guide washers 9a,9 b. The deactivation of the second spring 13-2 therefore makes it possible to increase the stiffness of the damping device in this second relative rotational direction beyond the fifth predetermined angular displacement threshold A5.

When the angular displacement in the second relative rotational direction reaches the fifth displacement threshold A5, the fifth stop b5 carried by the phasing member 15 is arranged to interact with the sixth stop b6 carried by the guide washers 9a,9 b.

The fifth stopper b5 is also formed on the lug 41 forming the first stopper b1. The first stopper b1 and the fifth stopper b5 are formed on two circumferentially opposite edges of the lug 41.

A sixth stopper b6 is formed on the second tooth 44, and the second tooth 44 also forms a fourth stopper b4. The fourth stopper b4 and the sixth stopper b6 are formed on two circumferentially opposite edges of the second tooth 44.

Thus, bringing the fifth stop b5 into contact with the sixth stop b6 makes it possible to stop the compression of the second spring 13-2 by directly transmitting torque between the fifth stop b5 of the phasing member 15 and the sixth stop b6 of the guide washers 9a,9b, thus increasing the stiffness of the damping device.

When the angular displacement between the web 7 and the guide washers 9a,9b in the second relative rotational direction from said relative angular position of repose reaches a sixth angular displacement threshold A6 between the web 7 and the guide washers 9a,9b, the torsional damping device has an angular position of maximum angular displacement. In other words, for torques greater than the torque producing the angular displacement equal to the sixth threshold A6, there is no further damping of the torque.

The sixth threshold A6 may be obtained by a stop and/or may correspond to a maximum compression of the spring.

The torsional damping means comprises a seventh stop b7 carried by the web 7, and the seventh stop b7 is arranged to interact with an eighth stop b8 carried by the second guide washer 9b when the angular displacement in the second relative rotational direction from the relative angular position of repose between the web 7 and the second guide washer 9b reaches a hexagonal threshold of displacement A6 between the web 7 and the guide washers 9a,9 b.

The seventh stopper b7 is formed on the hook 43 which also forms the third stopper b 3. The seventh stopper b7 and the third stopper b3 are formed on two circumferentially opposite edges of the hook 43.

The eighth stopper b8 is formed on the first tooth 42, and the first tooth 42 also forms the second stopper b2.

The second bearing surface 25b of each additional spring 25 is arranged to bear directly or indirectly against the first circumferential edges 47a2, 47b2 of the holes 47a and 47b in the first transmission plate 17a and in the second transmission plate 17b associated with said additional spring 25.

The second bearing surface 25b can bear directly or indirectly against the second actuation surface 48 of the web 7 when the angular displacement between the web 7 and the guide washers 9a,9b in the second relative rotational direction is greater than or equal to a fourth angular displacement threshold A4.

The first bearing surface 25a of each additional spring 25 is also arranged to bear directly or indirectly against the second circumferential edges 47a1, 47b1 of the holes 47a and 47b in the first and second transmission plates 17a,17b associated with said additional spring 25, the second circumferential edges 47a1, 47b1 being opposite to the first circumferential edges 47a2, 47b2.

The additional springs 25 are, if necessary, tightly mounted or sandwiched between the first circumferential edges 47a2, 47b2 of the holes in the first and second transmissions 17a and 17b and their second circumferential edges 47a1, 47b1. Each additional spring 25 can be prestressed in its housing L.

The damping device 1 also comprises friction means F intended to dissipate the energy of the spring and to avoid oscillation phenomena. In this case, the friction device F is arranged to rub only in the reverse drive direction. As regards the characteristics of this friction device, reference may be made to french patent application No. 1758778. Another conventional friction device is also conceivable.

In each damping module M1, M2, the first bearing seat 77 is interposed between the web 7 and the first spring 13-1 on the one hand, and between the guide washers 9a,9b and the first spring 13-1 of each damping module on the other hand. Likewise, the second bearing seat 78 is interposed between the web 7 and the second spring 13-2 on the one hand, and the guide washers 9a,9b and the second spring 13-2 on the other hand.

The first bearing surface 74 of the web 7 has a first recess 76, which first recess 76 is arranged to receive a pivot shaft protruding from a first seat 77. Likewise, the second bearing surface 73 of the web 7 has a second recess 75, which second recess 75 is arranged to receive a pivot shaft protruding from the second seat 78. The third bearing surface 94 has a third recess 96, the third recess 96 being arranged to receive a pivot shaft projecting from the first seat 77. The fourth bearing surface 93 also has a fourth recess 95, the fourth recess 95 being arranged to receive a pivot shaft projecting from the second seat 78.

In the second embodiment shown in fig. 9 and 10, third bearing 79 is interposed between phasing member 15 and first spring 13-1, and fourth bearing 80 is interposed between phasing member 15 and second spring 13-2 of each damping module.

The second and fourth bearing blocks 78, 80 are arranged to contact each other when the angular displacement between the web 7 and the guide washers 9a,9b in the first relative rotational direction is greater than or equal to a second threshold angular displacement A2 between the web 7 and the guide washers 9a,9 b. In other words, the first stopper b1 is formed on the fourth bearing 80, and the second stopper b2 is formed on the second bearing 78.

Each bearing 78, 80 has a cover arranged to radially hold the spring against which it bears against the centrifugal force. A first stopper b1 is formed at one end of the cover of the fourth bearing 80, and a second stopper b2 is formed at one end of the cover of the second bearing 78.

Fig. 13 and 14 show a third embodiment.

The two axial retaining elements of each drive head 17 are formed by eye cups 118a and 118b. The first and second transmission plates 17a,17b associated with a set of springs each include an eye cup portion 118a, 118b. To facilitate the making of the eye cup portions, two cutouts are formed in each plate, circumferentially on both sides of the portion of the plate for forming the eye cup portions.

One of the circumferential edges of each eye cup portion 118a, 118b forms a first stop b1 of the damping means, while the other circumferential edge of the eye cup portion forms a fifth stop b5 of the damping means.

Thus, each eye cup portion 118a, 118b is arranged to bear against the first tooth 142 forming the second stop b2 of the guide washer 9b when the angular displacement between the web 7 and the guide washer in the first relative rotational direction is greater than or equal to the second angular displacement threshold A2.

Conversely, each eyecup portion 118a, 118b is arranged to bear against the second tooth 144 of the sixth stop b6 forming the guide washer 9b when the angular displacement between the web 7 and the guide washer in the second relative rotational direction is greater than or equal to the fifth angular displacement threshold A5.

For each damping module, the guide washers 9a and 9b include a recess E4, which recess E4 extends between its first tooth 142 and second tooth 144 to allow movement of the eyecup portions 118a and 118b.

Each drive plate 17a,17b also includes a first centering member 65a, 65b disposed inboard of the first end 13-11 of the first spring 13-1 and a second centering member 66a, 66b disposed inboard of the first end 13-21 of the second spring 13-2.

Each centering member 65a, 65b, 66a, 66b is a tongue formed in the sheet metal of the plate and bent into a C-shape.

The tongue of the first centering member 65a forming the first transmission plate 17a and the tongue of the first centering member 65b forming the second transmission plate 17b are each arranged to axially face each other to form a centering tube 67 for centering the first spring. Likewise, the tongue of the second centering member 66a forming the first transmission plate 17a and the tongue of the second centering member 66b forming the second transmission plate 17b are arranged to axially face each other to form a centering tube 68 for centering the second spring 13-2.

Another solution is shown in fig. 11 and 12. In this case, the third 179 and fourth 180 bearing blocks are mounted to pivot on the centering member 115 about the same pivot pin 116.

Thus, the inclination of the third seat 179 and the fourth seat 180 may vary depending on the torque transmitted by the damping means and depending on the centrifugal force. The third 179 and/or fourth 180 bearing blocks are mounted to pivot about a spacer 116 for connecting the two phasing washers 15a and 15b, the spacer 116 forming the pivot pin of the block.

The third and fourth seats 179, 180 each have axially overlapping perforated connection tabs 192, and therefore their apertures also overlap, with the pivot pin 116 being inserted into both the apertures in the connection tabs 192 of the third seat 179 and the apertures in the connection tabs 192 of the fourth seat 180.

The third seat 179 and the fourth seat 180 each have a back-side bearing surface that interacts with the additional spring 25. These bearing surfaces are formed in the recesses 193 and 195 in the third and fourth seats 179 and 180. The third seat 179 is circumferentially interposed between the first spring 13-1 and the additional spring 25, and the fourth seat 180 is circumferentially interposed between the second spring 13-2 and the additional spring 25.

In other words, the additional spring 25 is sandwiched between the third seat 179 (via its first bearing surface 25 a) and the fourth seat 180 (via its second bearing surface 25 b). Thus, by means of the pivoting of the seat, an additional increase in rigidity can be obtained. In this case, the first spring, the second spring, and the additional spring are arranged in series, and the compression of the additional spring is delayed.

The third mount 179 has a first stud 81 disposed in a recess 197 in the first drive plate 117a, the end of the recess 197 being capable of limiting the movement 81 of the first stud and thus the pivoting of the third mount 179. The third seat has a second column pin 82 disposed in a recess of the second transmission plate 117b, an end of which recess is capable of restricting movement of the second column pin 82, thereby restricting pivoting of the third seat.

The fourth mount also has a first stud 81 disposed in a recess 198 in the first drive plate 117a, the end of which recess is capable of restricting movement of the first stud 81 and thus the pivoting of the fourth mount 180. The fourth seat 180 also has a second column pin 82 disposed in a recess of the second drive plate 117b, an end of which is capable of limiting movement of the second column pin, thereby limiting pivoting of the fourth seat 180.

Claims (15)

1. A torsional damping apparatus for a vehicle drive train, comprising:

a first rotational element (7) for transmitting torque;

a second rotational element (9) for transmitting torque;

at least one damping module (M1, M2) comprising main dampers (A) arranged between said first rotary element (7) and said second rotary element (9), each main damper comprising a set of springs comprising a first spring (13-1) and a second spring (13-2) arranged in series by means of a phasing member (15), said first spring (13-1) and said second spring (13-2) being provided between said first rotary element (7) and said phasing member (15) and between said phasing member (15) and said second rotary element (9), respectively, said first spring (13-1) and said second spring (13-2) allowing, when deformed, a relative rotation between said first rotary element (7) and said second rotary element (9) about a rotation axis (X);

characterized in that each damping module (M1, M2) comprises an additional spring (25) carried by the phasing member (15), the torsional damping means being configured such that, in a first relative direction of rotation of the first rotary element (7) with respect to the second rotary element (9) starting from a relative angle of repose position adopted by the first rotary element (7) and by the second rotary element (9) in which no speed or torque is applied:

when the angular displacement between the first and second rotary elements (7, 9) is less than a first threshold angular displacement (A1) between the first and second rotary elements (7, 9), the additional spring (25) is at a distance from the first rotary element (7) such that no additional torque can be transmitted between the phasing member (15) and the first rotary element (7) by the additional spring (25), and

when the angular displacement between the first rotary element (7) and the second rotary element (9) is greater than or equal to the first angular displacement threshold (A1), the additional spring (25) bears directly or indirectly against the first rotary element (7), so that an additional torque can be transmitted between the phasing member (15) and the first rotary element (7) through the additional spring (25).

2. A torsional damping device according to claim 1, wherein each additional spring (25) is a helical spring comprising:

a first bearing surface (25 a) arranged to bear directly or indirectly against the phasing member (15), and

a second bearing surface (25 b) capable of bearing directly or indirectly against a first actuating surface (40) of the first rotating element (7) when the angular displacement between the first rotating element (7) and the second rotating element (9) in the first relative rotational direction is greater than or equal to the first angular displacement threshold (A1).

3. A torsional damping device according to any of the preceding claims, wherein the torsional damping device is arranged such that each second spring (13-2) stops being compressed when an angular displacement between the first rotational element (7) and the second rotational element (9) in the first relative rotational direction from the relative angle of repose position is greater than or equal to a second threshold (A2) of angular displacement between the first rotational element (7) and the second rotational element (9).

4. A torsional damping device according to claim 3, wherein the torsional damping device comprises a first stop (b 1) carried by the phasing member (15), and the first stop (b 1) is arranged to interact with a second stop (b 2) carried by the second rotary element (9) when the angular displacement between the first rotary element (7) and the second rotary element (9) in the first relative direction of rotation from the relative angular position of rest is greater than or equal to a second threshold value of angular displacement (A2) between the first rotary element (7) and the second rotary element (9).

5. A torsional damping device according to claim 1 or 2, wherein one of the first and second rotary elements (7, 9) is formed by two guide washers (9 a,9 b) axially retaining the first and second springs (13-1, 13-2) of each set; and the other of the first rotary element (7) and the second rotary element (9) is formed by a web arranged axially between the two guide washers (9 a,9 b).

6. A torsional damping device according to claim 1 or 2, wherein an additional spring (25) of the damping module (M1, M2) is arranged at least partially circumferentially between the first spring (13-1) and the second spring (13-2) of the damping module.

7. A torsional damping device according to claim 1 or 2, wherein the phasing member comprises a radially extending annular portion arranged radially inside the first spring (13-1) and the second spring (13-2).

8. A torsional damping device according to claim 1 or 2, wherein each damping module (M1, M2) has at least one pair of transmission plates (17 a,17 b) carried by the phasing members, each pair of transmission plates comprising a first transmission plate (17 a) and a second transmission plate (17 b) axially spaced from each other; the first and second drive plates (17 a,17 b) each comprise a first thrust zone (P1) interacting directly or indirectly with the first end (13-11) of the first spring (13-1) and a second thrust zone (P2) interacting directly or indirectly with the first end (13-21) of the second spring (13-2), the first thrust zones of each pair of plates being axially spaced apart from each other and the second thrust zones of each pair of plates being axially spaced apart from each other.

9. The torsional damping device of claim 8, wherein the first and second drive plates (17 a,17 b) of each pair of drive plates are formed on first and second phasing washers (15 a, 15 b), respectively, axially spaced from each other.

10. A torsional damping device according to claim 1 or 2, wherein each damping module (M1, M2) comprises a drive head (17) carried by the phasing member (15) and arranged circumferentially between the first spring (13-1) and the second spring (13-2) of the damping module's spring group, each drive head (17) comprising a housing (L) in which an additional spring (25) of the damping module is housed, so as to transmit an additional torque between the phasing member (15) and the first rotary element (7) when the angular displacement in the first relative rotational direction between the first rotary element (7) and the second rotary element (9) is greater than or equal to the first angular displacement threshold (A1).

11. A torsional damping device according to claim 10, each damping module (M1, M2) having at least one pair of transmission plates (17 a,17 b) carried by the phasing members, each pair of transmission plates comprising a first transmission plate (17 a) and a second transmission plate (17 b) axially spaced from each other; said first and second transmission plates (17 a,17 b) each comprising a first thrust zone (P1) interacting directly or indirectly with the first end (13-11) of said first spring (13-1) and a second thrust zone (P2) interacting directly or indirectly with the first end (13-21) of said second spring (13-2), said first thrust zones of each pair of plates being axially spaced apart from each other and said second thrust zones of each pair of plates being axially spaced apart from each other, and wherein, for each damping module (M1, M2), said transmission head (17) is formed by a pair of transmission plates (17 a,17 b), each first (17 a) and second (17 b) transmission plate comprising a hole (47 a, 47 b), the holes (47 a, 47 b) in said first (17 a) and in said second (17 b) plate being arranged axially facing each other so as to accommodate an additional spring (25) of the corresponding damping module.

12. A torsional damping device according to claim 10, wherein each drive head (17) further comprises two axial holding elements (18 a, 18 b) for axially holding the associated additional spring (25), the two axial holding elements (18 a, 18 b) for the additional spring (25) being arranged axially on both sides of the additional spring (25).

13. A torsional damping device according to claim 1 or 2, wherein the torsional damping device is configured such that, in a second relative rotational direction, opposite to the first relative rotational direction, of the first rotational element (7) with respect to the second rotational element (9) from a relative angle of repose position assumed by the first and second rotational elements (7, 9) in which no speed or torque is applied:

each additional spring (25) is at a distance from the first rotating element (7) when the angular displacement between the first rotating element (7) and the second rotating element (9) is smaller than a fourth angular displacement threshold (A4) between the first rotating element (7) and the second rotating element (9), and

each additional spring bears directly or indirectly against the first rotary element (7) when the angular displacement between the first rotary element (7) and the second rotary element (9) is greater than or equal to the fourth angular displacement threshold (A4), so that an additional torque can be transmitted between the phasing member (15) and the first rotary element (7) through each additional spring (25).

14. The torsional damping device of claim 4, wherein each damping module (M1, M2) has at least one pair of transmission plates (17 a,17 b) carried by the phasing members, each pair of transmission plates comprising a first transmission plate (17 a) and a second transmission plate (17 b) axially spaced from each other; said first and second transmission plates (17 a,17 b) each comprising a first thrust zone (P1) interacting directly or indirectly with the first end (13-11) of said first spring (13-1) and a second thrust zone (P2) interacting directly or indirectly with the first end (13-21) of said second spring (13-2), said first thrust zones of each pair of plates being axially spaced from each other and said second thrust zones of each pair of plates being axially spaced from each other;

wherein the torsional damping device is configured such that, in a second relative rotational direction, opposite to the first relative rotational direction, of the first rotational element (7) with respect to the second rotational element (9) from a relative angle of repose position assumed by the first and second rotational elements (7, 9) at which no speed or torque is applied:

each additional spring (25) is at a distance from the first rotating element (7) when the angular displacement between the first rotating element (7) and the second rotating element (9) is smaller than a fourth angular displacement threshold (A4) between the first rotating element (7) and the second rotating element (9), and

each additional spring bears directly or indirectly against the first rotary element (7) when the angular displacement between the first rotary element (7) and the second rotary element (9) is greater than or equal to the fourth angular displacement threshold (A4), so that an additional torque can be transmitted between the phasing member (15) and the first rotary element (7) through each additional spring (25);

wherein the torsional damping device is arranged such that the second spring (13-2) stops being compressed when the angular displacement between the first rotary element (7) and the second rotary element (9) in the second relative rotational direction from the relative angular position of repose is greater than or equal to a fifth threshold angular displacement (A5) between the first rotary element (7) and the second rotary element (9), a fifth stop (b 5) being carried by the phasing member (15) and being arranged to interact with a sixth stop (b 6) carried by the second rotary element (9) when the angular displacement between the first rotary element (7) and the second rotary element (9) in the second relative rotational direction reaches a fifth threshold angular displacement (A5), the first and/or second drive plate (17 a,17 b) of the phasing member (15) having a drive lug (41) forming the first stop (b 1) and on this fifth stop (41) also forming a stop (A5).

15. A transmission system comprising a torque limiter comprising a friction disc and a damping device according to any preceding claim, the friction disc being rotationally mounted integrally with one of the first and second rotational elements (7, 9) of the damping device.

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