WO2023025663A1

WO2023025663A1 - Dual-mass flywheel

Info

Publication number: WO2023025663A1
Application number: PCT/EP2022/073121
Authority: WO
Inventors: Benjamin LAPORTE; Matthieu Malley; Nicola SAVASTANO
Original assignee: Valeo Embrayages
Priority date: 2021-08-24
Filing date: 2022-08-18
Publication date: 2023-03-02
Also published as: FR3126465B1; FR3126465A1

Abstract

The invention relates to a dual-mass flywheel (1) comprising a primary flywheel (2) intended to be fastened to a drive shaft and a secondary flywheel (3), the primary flywheel (2) and the secondary flywheel (3) being able to rotate with respect to each other about an axis of rotation X, the dual-mass flywheel (1) further comprising elastic members (8) configured to transmit a torque between the primary flywheel (2) and the secondary flywheel (3) and to damp rotational irregularities, the dual-mass flywheel (1) being characterized in that at least one among the primary flywheel (2) and the secondary flywheel (3) has a first element (17, 21) and a second element (18, 22) which are made of sheet metal and have different thicknesses and/or materials, the first element (17, 21) and the second element (18, 22) being arranged end to end and being fastened to each other by a weld (24, 26).

Description

Title of the invention: Double mass flywheel

Technical area

[1] The invention relates to the field of motor vehicle transmissions and relates more particularly to a dual mass flywheel.

Technology background

[2] Ignition engines do not generate a constant torque and exhibit acyclicity caused by successive explosions in their cylinders. These acyclisms generate vibrations which are likely to be transmitted to the gearbox and thus cause particularly undesirable shocks, noise and noise pollution.

[3] In order to reduce the undesirable effects of vibrations and improve motor vehicle driving comfort, certain motor vehicle transmissions are equipped with a dual mass flywheel. A double damped flywheel comprises a primary flywheel intended to be fixed at the end of an engine shaft, a secondary flywheel, coaxial with the primary flywheel, and elastic members interposed between the primary flywheel and the secondary flywheel to transmit a torque and dampen acyclisms of rotation between the primary flywheel and the secondary flywheel.

[4] The primary flywheel comprises a radially oriented annular portion which has holes in an internal zone through which screws pass intended to secure the primary flywheel to the nose of the engine shaft. The primary flywheel also comprises an axially oriented cylindrical skirt extending axially from the outer periphery of the radially oriented annular portion as well as an annular cover which is welded against the axially oriented cylindrical skirt. The annular cover defines with the radially oriented annular portion and the axially oriented cylindrical skirt, an annular chamber in which the elastic members are housed. The elastic members bear, on the one hand, against support lugs of the primary flywheel and, on the other hand, against support lugs of an annular web, the latter being housed between the cover and the portion annular radial orientation of the primary flywheel and fixed to the secondary flywheel.

[5] The secondary flywheel has a radially inner zone which has holes through which pass rivets securing the secondary flywheel to the annular web. [6] It is known to make the radially oriented annular portion and the axially oriented cylindrical skirt of the primary flywheel in one piece. These parts of the primary flywheel are made by machining a casting or more commonly by machining a stamped sheet of steel. The secondary flywheel is produced in a similar manner, that is to say by machining a casting or a stamped sheet formed in one piece.

[7] Such a process for manufacturing the primary and secondary flywheels is not satisfactory. Indeed, the primary and secondary flywheels have different zones with different thicknesses, the thickness being chosen according to the functionality of the zone. For example, the axially oriented cylindrical skirt of the primary flywheel may have a greater thickness than the radially oriented annular portion in order to increase the moment of inertia to mass ratio of the primary flywheel. Similarly, it may also be advantageous for the internal zone of the radially oriented annular portion to be thicker than the rest in order to reinforce the resistance of said internal zone which secures the primary flywheel to the engine shaft and thus undergoes the most important constraints. The production of a steering wheel having such variations in thickness requires numerous machining operations and leads to significant material losses, which has the effect in particular of negatively impacting the economic and environmental balance of the manufacturing operations of the double damping flywheel. In addition, given the aforementioned constraints, such a process for manufacturing a steering wheel does not allow the thickness of certain areas of the steering wheel to be limited to what is strictly necessary, in particular in its non-functional areas. This process therefore does not make it possible to optimally limit the mass of the double flywheel thus produced, which has a negative impact on the carbon dioxide emissions of motor vehicles equipped with such a double mass flywheel.

Summary

[8] One idea at the basis of the invention is therefore to propose a double mass flywheel as well as a method of manufacturing such a double mass flywheel which make it possible to solve the aforementioned drawbacks.

[9] To do this, according to a first aspect, the invention provides a double mass flywheel comprising a primary flywheel intended to be fixed to an engine shaft and a secondary flywheel, the primary flywheel and the secondary flywheel being movable in rotation the one with respect to the other around an axis of rotation X, the double mass flywheel further comprising elastic members configured to transmit a torque between the primary flywheel and the secondary flywheel and dampen rotational acyclics, the double mass flywheel being remarkable in that at least one of the primary flywheel and the flywheel secondary comprises a first element and a second element which are made of sheet metal and have different thicknesses and/or materials, the first element and the second element being arranged end to end and fixed to each other by welding.

[10] Thus, at least one of the primary and secondary flywheels of the dual mass flywheel is made by joining together two elements of different thicknesses and/or materials, which facilitates the manufacture of said steering wheel and lighten it.

[11] Within the meaning of this document, the term “welding” covers joints made with or without the addition of material.

[12] According to embodiments, such a dual mass flywheel may include one or more of the following characteristics.

[13] According to one embodiment, the primary flywheel comprises an annular portion of radial orientation, a cylindrical skirt of axial orientation projecting axially from an outer periphery of the annular portion of radial orientation and a cover fixed against an edge free from the axially oriented cylindrical skirt, the radially oriented annular portion comprising a zone equipped with orifices intended to receive fixing members for fixing the primary flywheel to an engine shaft. In a preferred example, the orifices are made in an internal zone of the radially oriented portion.

[14] According to one embodiment, the radially oriented annular portion, the axially oriented cylindrical skirt and the cover together form an annular chamber in which the elastic members are housed.

[15] According to one embodiment, the dual mass flywheel comprises an annular web which is housed between the cover and the radially oriented annular portion of the primary flywheel and which is fixed to the secondary flywheel, the elastic members being in support of on the one hand, against support sectors of the primary flywheel and, on the other hand, against support tabs of the annular web.

[16] According to one embodiment, the first element and the second element belong to the primary flywheel, the first element being arranged inside and in the extension in a radial direction of the second element, the first element forming the zone equipped with orifices of the radially oriented annular portion.

[17] Advantageously, in such an embodiment, the first element forming the zone equipped with orifices of the radially oriented annular portion has a thickness greater than that of the second element, which makes it possible to reinforce the resistance of said zone which secures the primary flywheel to the engine shaft and thus undergoes the greatest stresses. [18] Alternatively or additionally, the first element forming the zone equipped with orifices of the radially oriented annular portion is made of a material, such as steel, having a higher resistance than that of the material in which is realized the second element.

[19] According to one embodiment, the first element comprises cutouts distributed around the X axis and arranged to reduce the rigidity of the first element. Thus, the first element forms a flexible portion of the primary flywheel making it possible to dampen the excitations in the axial direction. According to an advantageous embodiment, the cutouts are regularly distributed around the X axis so as not to generate unbalance. However, according to another embodiment, the cutouts can also be irregularly distributed around the X axis.

[20] According to an alternative embodiment, the first element has a thickness such that it forms a flexible portion of the primary flywheel making it possible to dampen the excitations in the axial direction. In such a case, the cutouts are optional.

[21] According to one embodiment, the primary flywheel comprises a third element which forms at least a part of the axially oriented cylindrical skirt, the second element and the third element being made of sheet metal and having thicknesses and/or materials different, the third element and the second element being arranged end-to-end and fixed to each other by a weld.

[22] According to one embodiment, the third element which forms at least a part of the cylindrical skirt of axial orientation has a thickness greater than that of the second element. This makes it possible to increase the moment of inertia to mass ratio of the primary flywheel.

[23] According to an alternative or complementary embodiment, the third element which forms at least part of the cylindrical skirt of axial orientation is made of a material having a higher density than that of the material in which the first and the second element.

[24] According to one embodiment, the second element comprises a first portion extending radially and a second portion extending axially, the first portion being arranged in the extension in a radial direction of the first element and the second portion being arranged in the extension in a radial direction of the third element. [25] According to one embodiment, the third element comprises a first portion extending radially and a second portion extending axially, the first portion being arranged in the extension in a radial direction of the second element.

[26] According to one embodiment, the first element and the second element belong to the primary flywheel, the first element forming at least part of the annular portion of radial orientation and the second element forming at least part of the cylindrical skirt axial orientation.

[27] According to one embodiment, the second element forming at least a part of the axially oriented cylindrical skirt has a thickness greater than that of the first element, which makes it possible to increase the moment of inertia to mass ratio of the primary flywheel.

[28] According to an alternative or complementary embodiment, the second element which forms at least part of the cylindrical skirt of axial orientation is made of a material having a higher density than that of the material in which the first element is made.

[29] According to one embodiment, the second element comprises a first portion extending radially and a second portion extending axially, the first portion of the second element being arranged outside the first element in the extension along a direction radial of the first element.

[30] According to one embodiment, the first element and the second element belong to the secondary flywheel, the double damping flywheel comprising an annular web comprising support tabs cooperating with the elastic members, the first element being arranged inside and in the extension in a radial direction of the second element and being equipped with orifices traversed by rivets ensuring the attachment of the secondary flywheel to the annular web.

[31] According to one embodiment, the first element equipped with orifices traversed by rivets has a thickness greater than that of the second element, which makes it possible to reinforce the area of the secondary flywheel ensuring its attachment to the annular veil.

[32] Alternatively or additionally, the first element equipped with holes through which rivets pass is made of a material, such as steel, having a higher resistance than that of the material in which the second element is made.

[33] According to one embodiment, the secondary flywheel further comprises a third element which is arranged radially outside the second element and in the extension in a radial direction of the second element, the second element and the third element being made of sheet metal and having different thicknesses and/or materials, the third element and the second element being arranged end-to-end and fixed to each other by welding.

[34] According to an advantageous embodiment, the third element has a thickness greater than that of the first element, which makes it possible to increase the moment of inertia to mass ratio of the secondary flywheel.

[35] According to an alternative or complementary embodiment, the third element is made of a material having a higher density than that of the material in which the first and second elements are made.

[36] According to one embodiment, the first element and the second element are each made of a material chosen from among steel, aluminum, aluminum alloys, magnesium, magnesium alloys, tungsten and tungsten alloys.

[37] According to one embodiment, the third element is made of a material chosen from among steel, aluminum, aluminum alloys, magnesium, magnesium alloys, tungsten and tungsten alloys.

[38] According to one embodiment, the first element and the second element have a thickness of between 2 and 10 mm. According to one embodiment, the third element has a thickness of between 2 and 10 mm.

[39] According to one embodiment, the first element and the second have different thicknesses, the element among the first and the second element which has the greatest thickness being equipped with a peripheral shoulder against which the edge of the other element. This makes it possible in particular to facilitate the welding operations and to reinforce the mechanical strength of the junction.

[40] According to one embodiment, the invention relates to a method of manufacturing an aforementioned dual mass flywheel, comprising a step of shaping the first element and the second element and a step of welding the first element and the second end-to-end element.

[41] According to an advantageous embodiment, the first element and the second element are welded to each other end-to-end before being jointly shaped. This makes it possible in particular to simplify the welding operations.

[42] According to one embodiment, the welding step is carried out by laser welding.

[43] According to one embodiment, the shaping step is a stamping step. [44] According to one embodiment, the first element and the second element are cut, advantageously by a die-cut.

Brief description of figures

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

[46] Figure 1 is a sectional view of a dual mass flywheel according to one embodiment.

[47] Figure 2 is a partial sectional view of the primary flywheel of the dual mass flywheel of Figure 1.

[48] Figure 3 is a partial sectional view of the secondary flywheel of the dual mass flywheel of Figure 1.

[49] Figure 4 is a partial sectional view of a primary flywheel according to a second embodiment.

[50] Figure 5 is a partial sectional view of a primary flywheel according to a third embodiment.

[51] Figure 6 is a partial sectional view of a primary flywheel according to a fourth embodiment.

[52] Figure 7 is a partial sectional view of a primary flywheel according to a fifth embodiment.

[53] Figure 8 is a partial sectional view of a primary flywheel according to a sixth embodiment.

[54] Figure 9 is a partial sectional view of a primary flywheel according to a seventh embodiment.

[55] Figure 10 is a perspective view of part of the primary flywheel of Figure 9.

Description of embodiments

[56] In the description and the claims, the terms "external" and "internal" as well as the "axial" and "radial" orientations will be used to designate, according to the definitions given in the description, elements of the double mass flywheel . By convention, the "radial" orientation is directed orthogonally to the axis X of rotation of the dual mass flywheel determining the "axial" orientation and, from the inside outwards, moving away of said axis, the "circumferential" orientation is directed orthogonally to the axis of the device and orthogonal to the radial direction. The terms "external" and "internal" are used to define the relative position of one element with respect to another, with reference to the X axis of rotation of the device, an element close to the axis is thus qualified as internal as opposed to an external element located radially on the periphery.

[57] In connection with Figure 1, there is a double mass flywheel 1 according to a first embodiment. The dual mass flywheel 1 comprises a primary flywheel 2 intended to be fixed at the end of an engine shaft, that is to say the crankshaft of a combustion engine, not shown, and a secondary flywheel 3.

[58] The primary flywheel 2 and the secondary flywheel 3 are rotatable around the axis of rotation X and are, moreover, rotatable relative to each other, around said axis X.

[59] The primary flywheel 2 comprises an annular portion of radial orientation 4 and a cylindrical skirt of axial orientation 5 which extends axially from the outer periphery of the annular portion of radial orientation 4. The primary flywheel 2 also comprises a lid 6, annular, which is welded against the free edge of the cylindrical skirt of axial orientation 5. The lid 6 defines with the annular portion of radial orientation 4 and the cylindrical skirt of axial orientation 5, an annular chamber 7 .

[60] The double damped flywheel 1 also comprises elastic members 8 which make it possible to transmit a torque between the primary flywheel 2 and the secondary flywheel 3 and to dampen rotational acyclisms. The elastic members 8 are, for example, curved coil springs which are housed in the annular chamber 7 provided in the primary flywheel 2. Each of the elastic members 8 extends circumferentially between two support legs, not shown, of a annular web 9 which is integral in rotation with the secondary flywheel 3 and two support sectors, not shown, provided on the primary flywheel 2. Each support sector carried by the primary flywheel 2 is, for example, constituted by a boss formed in the radially oriented annular portion 4 and by a boss formed in the cover 6. Thus, in operation, each of the elastic members 8 bears, at a first end, against a support sector carried by the primary flywheel 2 and , at a second end, against a support tab provided on the annular web 9, so as to ensure the transmission of torque between the primary flywheel 2 and the secondary flywheel 3.

[61] The annular chamber 7 in which the elastic members 8 are housed is filled with a lubricating agent, preferably grease in order to limit the friction between the elastic members 8 and the primary flywheel 2. In order to avoid leaks of lubricant to the exterior of the annular chamber 7, the double damping flywheel 1 is equipped with sealing means arranged on either side of the annular web 9 and ensuring the sealing of the annular chamber 7, on the one hand, between the annular web 9 and the radially oriented annular portion 4 of the primary flywheel 2, and, on the other hand, between the annular web 9 and the cover 6. In the embodiment shown, the sealing means comprise two washers sealing 10, 11 which extend on either side of the annular web 9. Each sealing washer 10, 11 is formed by an elastically deformable sheet mounted axially prestressed. Each sealing washer 10, 11 is, on the one hand, riveted close to its radially internal edge on the annular web 9 and is, on the other hand, resting against a plastic washer 12, 13 positioned between the external edge of said sealing washer 10, 11 and cover 6 or radially oriented annular portion 4 of primary flywheel 2.

[62] Furthermore, the dual damped flywheel 1 advantageously comprises a friction device, not shown, also called a hysteresis device, which is capable of exerting a resisting friction torque during relative rotation between the primary flywheel 2 and the secondary flywheel 3. Thus, the torque is transmitted between the primary flywheel 2 and the secondary flywheel 3 by the elastic members 8 while the friction device makes it possible to dissipate the energy accumulated in the elastic members 8 so as to dampen the vibes.

[63] In the embodiment of Figure 1, the dual mass flywheel 1 comprises a hub 14 which is integral in rotation with the secondary flywheel 3 and the annular web 9. The hub 14 has internal splines intended to cooperate with splines complementary to a torque transmission device, such as a double clutch or a torque converter for example, which is able to transmit the torque from the double mass flywheel 1 to the wheels of the vehicle, for example via an input shaft of a gearbox. In the embodiment shown, the hub 14 comprises a flange 15 which is sandwiched between the annular web 9 and the secondary flywheel 3. In addition, the annular web 9, the hub 14 and the secondary flywheel 3 are fixed to each other. to the others by rivets 16 passing through orifices made in the three aforementioned elements.

[64] In another embodiment not shown, the secondary flywheel 3 is intended to be fixed to a cover of a clutch mechanism and comprises a flat annular surface intended to form a bearing surface for a friction lining of a clutch disc.

[65] As shown in Figures 1 and 2, the radially oriented annular portion 4 and the axially oriented cylindrical skirt 5 consist of a first, a second and a third separate elements 17, 18, 19 which are made of sheet metal and are welded to each other by welds 24, 25.

[66] The first element 17 forms a radially internal zone of the radially oriented annular portion 5. It has holes 20 intended for the passage of screws allowing the primary flywheel 2 to be fixed to the motor shaft. The second element 18 comprises a first portion extending radially in the extension of the first element 17 and a second portion extending axially in the extension of the third element 19. The first element 17 is arranged radially inside the first portion of the second element 18 and extends in the continuity of the first portion of the second element 18. The first element 17 and the second element 18 are welded and joined together, that is to say joined end to end. end. Thus, the outer peripheral edge of the first element 17 is placed against the inner peripheral edge of the second element 18. The outer peripheral edge of the first element 17 and the inner peripheral edge of the second element 17 are fixed to each other by the welding 24.

[67] Furthermore, the third element 19 extends axially and in the continuity of the second portion of the second element 18. The second element 18 and the third element 19 are welded and joined to each other, it is to say joined end to end. In other words, the front edge of the second element 18 is placed against the rear edge of the third element 19. The front edge of the second element 18 and the rear edge of the third element 19 are fixed to each other by a weld 25. According to one embodiment, the weld 25 extends continuously over 360° all around the axis X. According to another embodiment, the weld 25 is discontinuous.

[68] The first element 17 has a thickness greater than that of the second element 18, which makes it possible to reinforce the zone of the primary flywheel 2 ensuring its attachment to the motor shaft. Furthermore, the third element 19 has a thickness greater than that of the second element 18, which makes it possible to increase the moment of inertia of the primary flywheel 2. Alternatively or additionally, it is also possible to provide that the first, second and third elements 17, 18, 19 are made of different materials. It is for example possible to use different types of steel and/or different types of metals. Thus, according to a variant embodiment, the element likely to undergo the greatest stresses, here the first element 17, is made of high-strength steel while the other element(s), here the second and third elements 18, 19 are made of lower strength steel. According to an alternative or complementary variant, other metallic materials than steel can be used, for example an aluminum alloy, such as an alloy of aluminum and iron, in magnesium or magnesium alloy, tungsten or tungsten alloy. The aforementioned materials are chosen according to their density and the constraints linked to the inertia and to the mass of the primary flywheel to be produced.

[69] According to an advantageous embodiment, three flat sheets intended to form the first, the second and the third elements 17, 18, 19 are welded to each other, for example by laser welding, then the assembly thus produced is shaped by a stamping process. Alternatively, the sheets 17, 18, 19 can also be welded by other welding processes, such as cold welding processes, designated by the acronym CMT, arc welding processes designated by the acronyms TIG, MIG and resistance welding processes designated by the acronym ERW. Advantageously, the stamping process is carried out hot in order to facilitate shaping and confer final mechanical strength on the primary flywheel 2.

[70] In connection with Figures 1 and 3, the structure of the secondary flywheel 3 is described. The secondary flywheel 3 consists of a first element 21, a second element 22 and a third element 23 which are distinct are made of sheet metal and are welded edge-to-edge to each other by weld beads 26, 27. The first element 21 is arranged radially inside the second element and is equipped with orifices, one of which is shown in Figure 1, crossed by rivets 16 ensuring the attachment of the secondary flywheel 3 to the annular web 9. The first element 21 has a thickness greater than that of the second element 22, so as to reinforce the zone of the secondary flywheel 3 ensuring its attachment to the annular web 9. Furthermore, the third element 23 is disposed radially outside the second element 22. In the example shown, the third element 23 has a thickness greater than that of the second element 22, which makes it possible to increase the ratio ort moment of inertia on mass of the secondary flywheel 3. Alternatively or additionally, it is also possible to provide that the first, second and third elements 21, 22, 23 are made of different materials.

[71] Figure 4 illustrates a primary flywheel 2 according to another alternative embodiment. This alternative embodiment differs from that illustrated in FIG. 2 in that the third element 19 also forms part of the annular portion of radial orientation 4. To do this, the third element 19 comprises a first portion of radial orientation and a second portion of axial orientation. The first portion extends radially in the continuity of the second element 18 and is joined and welded to said second element 18. [72] Figure 5 partially illustrates a primary flywheel 2 according to yet another alternative embodiment. In this embodiment, the radially oriented annular portion 4 as well as the axially oriented cylindrical skirt 5 consist only of a first and a second distinct elements 17, 18. Thus, the second element 18 constitutes an outer zone of the radially oriented annular portion 4 as well as the entirety of the axially oriented cylindrical skirt 5. The second element 18 has a thickness less than that of the first element 17. This is advantageous for producing a primary flywheel 2 having a low mass.

[73] Figure 6 partially illustrates a primary flywheel 2 according to another alternative embodiment. This alternative embodiment differs from that described above in relation to FIG. 4 only in that the third element 19 has a thickness less than that of the second element 18. This also makes it possible to obtain a primary flywheel 2 having a low mass.

[74] According to alternative embodiments, as shown in Figures 7 and 8, at the junction between two elements 17, 18, the element 17 which has the greatest thickness has a peripheral shoulder 28 against which is placed the edge of the other element 18. This makes it possible in particular to facilitate the operations of welding the two elements 17, 18 to each other and to reinforce the mechanical strength at the junction between the two elements 17, 18. If, in the embodiment shown, such a junction is made between the first element 17 and the second element 18 of the primary flywheel 2, it is also possible to make it between the second element 18 and the third element 19 of the primary flywheel or between two of the first, second and third elements 21, 22, 23 of the secondary steering wheel 3.

[75] Figures 9 and 10 partially show a primary flywheel 2 according to another alternative embodiment. In this embodiment, the annular portion of radial orientation 4 as well as the cylindrical skirt of axial orientation 5 consist only of a first and a second distinct elements 17, 18. In addition, the first element 17 has a thickness less than that of the second element 18. The first element 17 here forms a flexible portion of the primary flywheel 2 which is intended to dampen the excitations in the axial direction.

[76] To do this, as shown in Figure 10, the first element 17 has cutouts 29 regularly distributed around the axis X and to reduce the rigidity of the first element 17. It will also be noted that in the variant represents , the first element 17 comprises several series of cutouts which are each located on different diameters. [77] Although the invention has been described in connection with several particular embodiments, it is quite obvious that it is in no way limited thereto and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

[78] The use of the verb “to comprise”, “to understand” or “to include” and of its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim.

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

Claims

[Claim 1] Double mass flywheel (1) comprising a primary flywheel (2) intended to be fixed to an engine shaft and a secondary flywheel (3), the primary flywheel (2) and the secondary flywheel (3) being rotatable relative to each other about an axis of rotation X, the dual mass flywheel (1) further comprising elastic members (8) configured to transmit a torque between the primary flywheel (2) and the secondary flywheel (3) and dampen rotational acyclisms, the dual damped flywheel (1) being characterized in that at least one of the primary flywheel (2) and the secondary flywheel (3) comprises a first element (17, 21) and a second element (18, 22) which are made of sheet metal and have different thicknesses and/or materials, the first element (17, 21) and the second element (18, 22) being arranged end to end and fixed to each other by a weld (24, 26).

[Claim 2] Double mass flywheel (1) according to claim 1, in which the primary flywheel (2) comprises an annular portion of radial orientation (4), a cylindrical skirt of axial orientation (5) projecting axially from a outer periphery of the annular portion of radial orientation (4) and a cover (6) fixed against a free edge of the cylindrical skirt of axial orientation (5), the annular portion of radial orientation (4) comprising a zone equipped orifices intended to receive fixing members for fixing the primary flywheel (2) to an engine shaft.

[Claim 3] Double mass flywheel (1) according to claim 2, wherein the first element (17) and the second element (18) belong to the primary flywheel (2), the first element (17) being arranged inside and in the extension in a radial direction of the second element (18), the first element (17) forming the zone equipped with orifices of the radially oriented annular portion (4).

[Claim 4] Double mass flywheel (1) according to claim 3, in which the first element (17) comprises cutouts (29) distributed around the axis X and arranged to reduce the rigidity of the first element (17).

[Claim 5] Double damped flywheel (1) according to claim 3 or 4, in which the primary flywheel (2) comprises a third element (19) which forms at least part of the cylindrical skirt of axial orientation (5), the second element (18) and the third element (19) being made of sheet metal and having different thicknesses and/or materials, the third element (19) and the second element (18) being arranged end-to-end and fixed to each other by a weld (25).

[Claim 6] A dual mass flywheel (1) according to claim 5, wherein the second member (18) comprises a first radially extending portion and a second axially extending portion, the first portion being disposed in the extension in a radial direction of the first element (17) and the second portion being arranged in the extension in a radial direction of the third element (19).

[Claim 7] Double mass flywheel (1) according to claim 5, in which the third element (19) comprises a first portion extending radially and a second portion extending axially, the first portion being arranged in the extension according to a radial direction of the second element (18).

[Claim 8] Double mass flywheel (1) according to claim 2, in which the first element (17) and the second element (18) belong to the primary flywheel (2), the first element forming at least part of the annular portion of radial orientation (4) and the second element (18) forming at least a part of the cylindrical skirt of axial orientation (5).

[Claim 9] A dual mass flywheel (1) according to claim 8, in which the second element (18) comprises a first portion extending radially and a second portion extending axially, the first portion of the second element (18) being arranged outside the first element (17) in the extension in a radial direction of the first element (17).

[Claim 10] Double mass flywheel (1) according to claim 1 or 2, in which the first element (21) and the second element (22) belong to the secondary flywheel (3), the double mass flywheel (1) comprising a ring (9) comprising bearing lugs cooperating with the elastic members (8), the first element (21) being disposed inside and in the extension in a radial direction of the second element (22) and being equipped with orifices traversed by rivets (16) securing the secondary wheel (3) to the annular web (9).

[Claim 11] Double mass flywheel (1) according to claim 9 or 10, wherein the secondary flywheel (3) further comprises a third element (23) which is arranged radially outside the second element (22) and in the extension in a radial direction of the second element (22), the second element (22) and the third element (23) being made of sheet metal and having different thicknesses and/or materials, the third element (23) and the second element (22) being arranged end-to-end and fixed to one another by a weld (27).

[Claim 12] Double mass flywheel (1) according to any one of claims 1 to 11, in which the first element (17) and the second element (18) have different thicknesses, the element among the first and the second element which has the greatest thickness being equipped with a peripheral shoulder (28) against which the edge of the other element is placed. 16

[Claim 13] A method of manufacturing a dual mass flywheel (1) according to any one of claims 1 to 12, comprising a step of shaping the first element (17, 21) and the second element (18, 22 ) and a step of welding the first element (17, 21) and the second element (18, 22) end to end.

[Claim 14] A manufacturing method according to claim 13, in which the first element (17, 21) and the second element (18, 22) are welded together end-to-end before being joined together. shaped.

[Claim 15] A manufacturing method according to claim 14 or 15, wherein the welding step is carried out by laser welding.