FR3059383A1 - MOTOR VEHICLE CLUTCH SUBASSEMBLY, TRANSMISSION SYSTEM COMPRISING SAID SUBASSEMBLY AND METHOD FOR ASSEMBLING SUCH A SYSTEM - Google Patents

Abstract

The invention relates, on the one hand; a clutch subassembly of a motor vehicle comprising, on the one hand, a clutch mechanism provided with a cover (2) and, on the other hand, fastening elements (3) housed in through orifices (20) of the cover (2) and intended to assemble the subassembly to a flywheel (1) by screwing at least one threaded end portion (31) of said fastening elements (3) in threaded bores (20) of said flywheel, characterized in that said orifices (20) of the cover are provided with retaining elements ensuring the positioning and temporary mounting of the fastening elements (3) on the cover (2) by axial retention their threaded end portion (31) and secondly; a transmission system comprising, in particular, the subassembly and a method for assembling said system

Description

© Publication no .: 3,059,383 (to be used only for reproduction orders)

©) National registration number: 16 61692 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY

COURBEVOIE © Int Cl ⁸ : F16 F15 / 315 (2017.01), F16D 13/58

A1 PATENT APPLICATION

©) Date of filing: 30.11.16. © Applicant (s): VALEO EMBRAYAGES Company by ©) Priority: simplified actions - FR. @ Inventor (s): BRAILLY JULIEN and DELIENCOURT NICOLAS. (43) Date of public availability of the request: 01.06.18 Bulletin 18/22. ©) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ® Holder (s): VALEO EMBRAYAGES Company by related: simplified actions. ©) Extension request (s): ©) Agent (s): VALEO EMBRAYAGES Company by simplified actions.

MOTOR VEHICLE CLUTCH SUB-ASSEMBLY, TRANSMISSION SYSTEM COMPRISING SUCH ASSEMBLY, AND METHOD FOR ASSEMBLING SUCH A SYSTEM.

FR 3,059,383 - A1 (5 £) The invention relates, on the one hand;

- a motor vehicle clutch sub-assembly comprising, on the one hand, a clutch mechanism provided with a cover (2) and, on the other hand, fixing elements (3) housed in through orifices (20) of the cover (2) and intended to ensure the assembly of the sub-assembly to a flywheel (1) by screwing at least one threaded end portion (31) of said fastening elements (3) in threaded bores (20) of said flywheel, characterized in that said holes (20) of the cover are provided with retaining elements ensuring the positioning and the provisional mounting of the fixing elements (3) on the cover (2) by an axial retention their threaded end portion (31) and, on the other hand;

- a transmission system comprising, in particular, the subassembly as well as a method of assembling said system

MOTOR VEHICLE CLUTCH SUB-ASSEMBLY, TRANSMISSION SYSTEM COMPRISING SUCH ASSEMBLY AND METHOD FOR ASSEMBLING SUCH A SYSTEM [0001] The invention relates both to a clutch sub-assembly, to a transmission system comprising this subassembly as well as a method of assembling said transmission system.

The invention more particularly relates to a sub-assembly comprising a clutch mechanism provided with a cover pre-fitted with elements for fixing to a flywheel.

STATE OF THE PRIOR ART Motor vehicle clutch mechanisms comprising, in particular, a cover, a diaphragm and a pressure plate, are generally assembled with a flywheel connected to the engine crankshaft. This flywheel, said flywheel and the cover, are intended to be secured by means of at least partially threaded fastening elements, housed in holes passing through the cover and intended to be screwed into tapped bores of the flywheel.

In the field of transmission systems, it is known to provide the engine crankshaft with a damping double flywheel itself provided with pre-assembled fastening elements.

Thus, the FR2973464 describes a clutch with a double damping flywheel in which an elastically deformable insert ensures the retention of the traditional fixing elements of the crankshaft in holes made in the secondary flywheel of the double damping flywheel.

In FR 2958704, it is a sealing plate which, by elastic clamping, ensures the retention of the fastening elements on the double damping flywheel.

However, there is currently a strong trend towards an increase in engine torques which is thwarted by the desire to minimize the dimensions of the clutch, and in particular its diametrical size or at least to maintain it at current values. to maintain a certain lightness and reduce its size.

However, such a compromise imposes a necessary optimization of the performance of the clutch mechanisms in order to increase the setting values without degrading the performance of the system because, in the presence of high torques, the cover enclosing the clutch mechanism is then subjected to deformation constraints.

This objective can be achieved, for example, by replacing the steel cover with a cast iron cover which provides a significant gain in stiffness. However, for reasons of mechanical strength, the cast iron cover has a significantly greater thickness than the steel cover, in particular, in the areas intended for fitting the fastening elements to the flywheel, [0010] However, the elements of traditional fasteners, which generally consist of standard size and / or size screws used on the assembly lines of the car manufacturer, are then too short and therefore prove to be unsuitable for allowing the assembly of a cast iron cover on the steering wheel engine.

Under these conditions, the use of these standard fasteners is no longer possible and it is therefore necessary to use the integration of specific fasteners which raises supply difficulties, management constraints of supplies from the car manufacturer, causes a slowdown in industrial production rates and also generates risks of reference errors. Consequently, this latter solution leads to technical and logistical problems and significant additional production costs.

Another technical problem lies in the provision of specific fastening elements carrying micro-beads of glue constituting an encapsulated adhesive called “thread locker” and of the risk of destruction of these micro-beads during the implementation of the process for pre-assembling the fastening elements on the clutch mechanism. This adhesive, which is deposited on the threaded end portion of the fastening elements, is intended to seal them in the tapped bores of the flywheel, guaranteeing a firm and final fixing. However, during the fitting of the fastening elements, these micro-balls can be crushed and the adhesive properties are then deteriorated even before the introduction of these elements into the orifices of the flywheel.

PRESENTATION OF THE INVENTION The invention aims to remedy the drawbacks of the state of the art by seeking to produce an integral sub-assembly consisting of the clutch mechanism and specific fixing elements for assembly to the flywheel thereby avoiding current operations of supply and installation of standard fasteners.

For this purpose, the invention provides a motor vehicle subassembly comprising, on the one hand, a clutch mechanism provided with a cover and, on the other hand, fixing elements housed in orifices through the cover and intended to ensure the assembly of the sub-assembly to a flywheel by screwing at least one threaded end portion of said fastening elements in tapped bores of said flywheel, characterized in that said orifices in the cover are provided with retaining elements ensuring the positioning and the provisional mounting of the fixing elements on the cover by an axial maintenance of their threaded end portion.

According to a first variant of the invention, the retaining elements consist of a threaded section of the inner wall of said holes in the cover.

According to an advantageous characteristic, the height of the threaded section of the orifices of the cover is less than or equal to the height of the threaded portion of the fastening elements.

According to a specific variant, the threaded section of the orifices in the cover forms a constriction of material at the upper part of said orifices.

Preferably, the lower part of the orifices of the cover has an inside diameter greater than the outside diameter of the threaded end portion of the fastening elements.

According to another characteristic, the height of the threaded end portion of the fastening elements is less than the height of the lower part of the holes in the cover. This height offset has the advantage of leaving axial freedom for the fastening elements after their introduction into the holes in the cover. Consequently, the introduction thread of the threaded end portion of the fastening elements is not constrained when it is inserted into the tapped bore of the flywheel.

According to a second alternative embodiment, the retaining elements consist of cylindrical inserts at least partially fitted inside said orifices and which are temporarily connected to the threaded end portion of the fastening elements.

Preferably, these inserts are at least partially threaded and are connected by screwing to the threaded end portion of the fastening elements.

According to another variant, the inserts are fitted inside the orifices of the cover until they come to bear axially against a shoulder forming a stop, machined in said orifices.

According to yet another variant, the inserts have a lower nozzle of smaller diameter intended to facilitate its introduction into said orifices.

According to an advantageous characteristic, the inserts are provided with anti-rotation lateral grooves cooperating with the inner wall of the orifices of the cover.

According to a preferred embodiment, the fastening elements are screws comprising a threaded end portion surmounted by an enlarged head.

In order to adapt to these latter variants, the threaded end portion of the fastening elements is surmounted by a smooth portion whose outside diameter is less than the inside diameter of the through holes of the cover. The smooth portion is located between the enlarged head and the threaded end portion.

Alternatively to adapt to the other variants, the threaded end portion extends over the entire length of the screws.

According to another variant, the screws comprise an axial superposition of two threads of different outside diameters, the smallest of the outside diameters being located on the end portion of the screws.

In the latter case, the outside diameter of the thread located on the end portion of the screws is less than the inside diameter of the tapped section of the holes in the cover. This configuration allows the deposition of the encapsulated glue called "thread locker" on the screws before their insertion into the holes in the cover. There is no longer any risk of deterioration of the pre-gluing of the fastening elements before their introduction into the tapped bores of the flywheel.

According to a first embodiment, the cover is made by molding a cast iron based on iron-carbon alloy.

According to a second embodiment, the cover is made by molding an aluminum-based foundry alloy.

According to a third embodiment, the cover is made of stamped sheet steel.

In the latter mode, the retaining elements consist of clamps mounted radially on the rim of the cover, the facing arms are provided with openings coming to align with said orifices and through which the portion is retained threaded fasteners.

Another object of the invention is a transmission system comprising a flywheel, a clutch disc and a clutch sub-assembly as defined above.

In this transmission system, it is expected that the threaded end portion of the fastening elements of the subassembly has a height substantially equal to the depth of the tapped bores of the flywheel.

Yet another object of the invention is a method of assembling a transmission system for a motor vehicle comprising a flywheel provided with threaded bores and a clutch mechanism provided with a cover itself provided with through holes which are secured by means of fastening elements having at least one threaded end portion, introduced into the through holes of the cover then screwed into the threaded bores of the flywheel, characterized in that a pre -assembly of the fastening elements on the cover by providing said orifices with retaining elements cooperating with at least the threaded end portion of said fastening elements to position them prior to their screwing in the tapped bores of the flywheel.

According to an advantageous characteristic of the method, a layer of encapsulated adhesive is deposited at least on the threaded end portion of the fastening elements after introduction of their threaded end portion in said retaining elements.

The invention finds more particularly its application on the assembly lines of the clutches where the assembly of the various components is carried out and then at the manufacturer or the automobile repairer who performs the final installation of the subassembly on the flywheel.

By replacing the steel cover with a cast iron cover, it becomes possible to use specific fastening elements which are then previously mounted on the cover and the threaded end portion of which is always adapted to the threaded bores of the flywheel. These fasteners are supplied to the manufacturer together with the clutch mechanism and by a single supplier.

The sub-assembly consisting of the clutch mechanism and its own fastening elements thus forms a whole, ready for assembly to the flywheel, without it being necessary to be concerned with the supply and installation. other fasteners. This results in a significant saving in production time.

In addition, with the assembly method of the transmission system of the invention providing for the prior mounting of the fastening elements on the cover, the deposition of the encapsulated glue called "thread locker" on the fastening elements can be performed after they are inserted and positioned in the holes in the cover. This method thus preserves the integrity of the micro-beads of the adhesive, which allows it to retain its adhesive properties until the final screwing in the bores of the flywheel.

BRIEF DESCRIPTION OF THE FIGURES

Other characteristics and advantages of the invention will emerge on reading the description which follows, with reference to the appended and detailed figures below.

FIGS. IA, IB and IC represent views, respectively, in perspective, in section along a diametral plane and in detail section of a first embodiment of the clutch subassembly of the invention, FIGS. 2A and 2B represent views, respectively, in perspective, and in section along a diametrical plane of a second embodiment of the clutch sub-assembly of the invention, FIGS. 3A and 3B represent views, respectively, in perspective, and in section along a diametrical plane of a variant of the second embodiment of the clutch sub-assembly of the invention, FIGS. 4A and 4B show views, respectively, in partial perspective, and in half-section along a diametral plane of a third embodiment of the clutch sub-assembly of the invention, FIGS. 5A and 5B represent views in partial perspective, respectively, in exploded view and in assembly of a fourth embodiment ization of the clutch sub-assembly of the invention.

FIG. 6 represents a detailed view in section of a fifth embodiment of the clutch sub-assembly of the invention.

For the sake of clarity, identical or similar elements are identified by identical reference signs in all of the figures. The upper part of the figures is on the side of the gearbox while the lower part is on the side of the flywheel.

DETAILED DESCRIPTION OF EMBODIMENTS Naturally, the embodiments illustrated by the figures presented above are given only by way of nonlimiting examples. It is explicitly provided that we can combine these different modes and variants to offer others.

According to one of its aspects, the invention relates to a sub-assembly intended to facilitate the integration of a clutch mechanism in a transmission chain between a crankshaft of an internal combustion engine (not shown) and an input shaft of a gearbox (not shown). This clutch mechanism is generally housed in a transmission system which consists, in particular, of the assembly of at least one flywheel 1 secured, directly or indirectly, on the one hand to the crankshaft and, on the other hand, to a cover 2 for closing the clutch mechanism. For the sake of clarity, the flywheel 1 has only been shown in section and in FIG. 1B alone. Between the flywheel and the clutch mechanism is interposed a clutch disc (shown in Figure IB but not referenced).

As illustrated, in particular, by Figures IA, 2A, 3A, 4A, 5A and 6, the attachment of the cover 2 to the steering wheel 1 is achieved by means of fastening elements 3 including at least one lower end portion 31 is threaded. These fastening elements 3 are housed in through orifices 20 of the cover 2 and are intended to be screwed into tapped bores 10 made opposite in the flywheel 1.

The cover 2 is made either of cast iron (Figures ΙΑ, 2A and 3A), or of stamped sheet steel (Figures 4A and 5A). Its thickness is less important in the second case than in the first case but its stiffness is then less. The embodiments of Figures ΙΑ, 2A and 3A, which are more particularly suitable for cast iron covers, proceed from an assembly of the fastening elements 3 on the cover 2 by the interior of its orifices 20 while the modes of embodiment of FIGS. 4A and 5A consist of an assembly of the fastening elements 3 on the cover 2 from the outside of these orifices 20.

In the two embodiments illustrated, respectively, by Figures 2A, 2B and 5A, 5B, the fastening elements 3 consist of screws of which at least one end portion is threaded and which are surmounted by enlarged heads 33 offering the grip to a screwing or tightening tool (not shown). In these embodiments, the threaded end portion extends over the entire length of the screw.

However, in the other embodiments (Figures ΙΑ, 3A and 4A, in particular), the threaded end portion 31 of the fastening elements 3, still in the form of a screw, is surmounted by a smooth portion 32 (non-threaded portion) located between the enlarged head 33 and the threaded end portion 31 whose outside diameter is less than the inside diameter of the through holes 20 of the cover 2. In all cases, the threaded end portion 31 of the fastening elements 3 has a height substantially equal to the depth of the tapped bores 10 of the flywheel 1.

The clutch subassembly according to the invention aims to achieve a pre-assembly of the fastening elements 3 on the cover 2 before mounting on the flywheel 1. For this purpose, the holes 20 of the cover 2 are provided with retaining elements ensuring the positioning and the provisional mounting of the fixing elements 3 on the cover by an axial retention of their threaded end portion 31.

In the embodiment of Figures IA, IB and IC, the retaining elements consist of a threaded section 21 formed directly on the inner wall of the orifices 20 of the cast iron cover and into which is screwed the portion of threaded end 31 of the fixing screws 3. The geometry of a cast iron cover requires thicknesses of material greater than those of a cover made of stamped sheet steel and therefore allows machining of the tapped section.

The height of this threaded section 21 is less than or equal to the height of the threaded portion 31 of the fastening elements and forms a shrinkage of material on the upper part of the through holes 20 of the cover 2. The axial retention is done by contacting and engaging the necked material with the threaded end portion of the screw.

The lower part 24 of the orifices 20 of the cover has an inner diameter greater than the outer diameter of the threaded end portion 31 of the fastening elements 3. The height of the threaded end portion 31 is then less than the height of the lower part 24 of the holes in the cover.

Similarly, the material shrinkage of the threaded section 21 has an inside diameter greater than the outside diameter of the smooth portion 32 of the screw 3.

Under these conditions, once screwed, the threaded end portion 31 located at the lower end of the screw 3 comes out from the bottom of the threaded section 21 and is then axially free. However, the screw still remains trapped in the through orifice 20, both upwards because its enlarged head 33 rests on the outer rim of the orifice 20 and downwards because its threaded portion 31 is blocked under the constriction of tapped material 21, as illustrated in Figure IC. This shrinkage of material ensures axial retention of the threaded end portion of the screw 3.

An alternative variant shown in Figure 6 is to produce the threaded section 21 of the orifices 20 with an internal diameter of thread greater than the diameter of the thread fl of the end portion 31 of the screws. Jointly, it is then expected that the screws 3 have an intermediate portion 32 with a thread f2 adapted to the tapped section 21 of the orifices and the presence of a smooth wall at the lower part 24 of the orifices 20 whose internal diameter is greater than that of the tapped section 21.

The screws 3 thus comprise an axial superposition of two threads fl, f2 of different outside diameters, the smallest of the outside diameters fl being located on their end portion 31 which, in this variant, therefore does not come in contact with the thread of the threaded section 21 of the orifices 20.

In this configuration, because the outside diameter of the thread fl located on the end portion 31 of the screws is less than the inside diameter of the threaded section 21 of the holes 20 of the cover 2, it is possible to pre-glue the screws before their insertion into the holes 20 of the cover.

In the embodiment of Figures 2A and 2B, the elements ensuring the retention of the screws 3 consist of cylindrical inserts 4 reported in the form of independent parts and fitted here integrally, optionally in force, inside the orifices 20 of cover 2.

The inserts 4 are placed in the orifices 20, either before the introduction of the screws 3 intended for attachment to the flywheel 1, in particular, if these inserts are made of plastic, or jointly with the screws 3 by being previously connected at their threaded end portion 31, if these inserts 4 are made of metal and tapped. In this embodiment with insert, provision is made for the screws 3 to be threaded over a height at least equal to the sum of the height of the inserts 4 and the depth of the tapped bores 10 of the flywheel 1 and, preferably, over any their height which guarantees, in the pre-assembly position, their retention in the orifices of the cover.

In the variant with plastic insert, the connection with the thread of the screws 3 is preferably obtained by deformation of the insert 4 while in the variant with metal insert, the connection with the screws is made by a simple screwing. In both cases, the inserts 4 remain housed in the orifices 20 of the cover after final screwing of the fastening elements 3 in the bores 10 of the steering wheel.

In the embodiment of Figures 3A and 3B, the retaining inserts 4 are metallic and are fitted, prior to the installation of the screws 3, inside the orifices 20 where they are blocked in axial translation downwards by axial support against a shoulder 22 forming a stop, machined in the orifices 20.

Where appropriate and according to a variant not shown, the inserts are provided with anti-rotation lateral grooves cooperating with the inner wall of the orifices of the cover.

In the embodiment illustrated in FIGS. 4A and 4B which applies more particularly to stamped covers made of sheet steel, the shoulder 22 ensuring the axial locking of the retaining inserts 4 is formed by the upper edge of the holes 20 of the cover and the insert is supported on an outer skirt 23 formed at the periphery of the cover.

In this case, the inserts 4 have a lower tip 40 which is the only one capable of being inserted into the orifices 20 of shallow depth while their upper section 41, of larger diameter, is held outside, in bearing on the shoulder 23 delimiting the upper periphery of the orifices 20. Preferably, the threaded lower end portion 31 of the screws 3 is engaged as far as the end piece 40. The cylindrical insert 4 comprises a tapped section produced on the wall of its axial and transverse inner duct. This tapped section forms a shrinkage of material at the upper part of the interior through duct.

In the embodiment illustrated in Figures 5A and 5B which also applies to stamped covers of sheet steel, the retaining elements consist of clips 5 mounted radially on the edge of the cover 2, before installation screws 3 which are here preferably threaded over their entire length.

The branches 51, 42 facing the clamps 5 are provided with openings 50 coming to align with the holes 20 of the cover 2 and through which is retained the threaded portion 31 of the fastening elements 3. The branch lower 51 of the clamps 5 is intended to be positioned under the through holes 20 of the cover 2 to be inserted between the respective flanges of the cover 2 and of the flywheel 1 (not visible in this figure).

The openings 50 made in the branches 51, 52 have, on their periphery, notches 50a facilitating the engagement of the thread of the screws 3 during the pre-assembly phase on the cover 2.

The method of pre-assembly of the fastening elements on the cover, 5 according to the invention, therefore consists in performing a pre-assembly of the fastening elements 3 with the cover 2 by providing its through holes 20 with elements of retainers such as threaded sections 21, inserts 4 or clamps 5 reported, in which at least the threaded end portion 31 of these fastening elements is temporarily mounted. Provisional and removable mounting is effected by axial retention of the threaded end portion.

A variant of the method of the invention provides for depositing a layer of encapsulated adhesive of the "threadlocker" type at least on the threaded end portion of the fastening elements.

Preferably and in order to preserve the adhesive properties of the adhesive, the layer of encapsulated adhesive is deposited on the fixing elements after introduction of their threaded portion into the retaining elements.

Claims (17)

1. Motor vehicle clutch sub-assembly comprising, on the one hand, a clutch mechanism provided with a cover (2) and, on the other hand, 5 fixing elements (3) housed in through holes (20) of the cover (2) and intended to ensure the assembly of the sub-assembly to a flywheel (1) by screwing at least one threaded end portion (31) of said fixing elements (3) in threaded bores (20) of said flywheel, characterized in that said holes (20) of the cover are provided with retaining elements ensuring the 10 positioning and provisional mounting of the fastening elements (3) on the cover (2) by axial maintenance of their threaded end portion (31). 2. Sub-assembly according to claim 1, characterized in that said retaining elements consist of a threaded section (21) of the inner wall of said orifices (20) of the cover (2). 15 3. Sub-assembly according to one of the preceding claims, characterized in that said tapped section (21) of the orifices (20) of the cover (2) forms a shrinkage of material at the upper part of said orifices. 4. Sub-assembly according to the preceding claim, characterized in that the lower part (24) of the orifices (20) of the cover (2) has an internal diameter 20 greater than the outside diameter of the threaded end portion (31) of the fastening elements (3). 5. Subassembly according to one of the preceding claims, characterized in that the height of the threaded end portion (31) is less than the height of the lower part (24) of the orifices (20) of the cover (2 ). 25 6. Subassembly according to one of the preceding claims, characterized in that said fixing elements (3) comprise an axial superposition of two threads (fl, f2) of different outside diameters, the smallest of the outside diameters (fl) being located on the end portion (31) of said fastening elements. 30 7. Sub-assembly according to the preceding claim, characterized in that the external diameter of the thread (fl) located on the end portion (31) of said fixing elements (3) is less than the internal diameter of the tapped section (21 ) holes (20) of the cover (2). 8. Sub-assembly according to claim 1, characterized in that said retaining elements consist of cylindrical inserts (4) at least partially fitted inside said orifices (20) and which are temporarily connected to the portion threaded end (31) of the fastening elements (3). 9. Sub-assembly according to the preceding claim, characterized in that said inserts (4) are at least partially tapped and are connected by screwing to the threaded end portion (31) of the fastening elements (3). 10. Sub-assembly according to one of claims 8 or 9, characterized in that said inserts (4) are fitted inside the orifices (20) of the cover (2) until they come to bear axially against a shoulder (22) forming a stop, machined in said orifices (20). 11. Subassembly according to one of the preceding claims, characterized in that the threaded end portion (31) of the fastening elements (3) is surmounted by a smooth portion (32) whose outside diameter is less than inner diameter of the through holes (20) of the cover (2) and the height is greater than or equal to the depth of said holes. 12. Sub-assembly according to one of the preceding claims, characterized in that said cover (2) is produced by molding a cast iron based on fercarbone alloy or by molding an aluminum alloy foundry . 13. The subassembly according to claim 1, characterized in that the cover (2) is made of stamped sheet steel. 14. Sub-assembly according to the preceding claim, characterized in that said retaining elements consist of clamps (5) mounted radially on the edge of the cover (2) whose arms facing each other (51, 52) are provided with 'openings (50) coming into alignment with said orifices (20) and through which the threaded portion (31) of the fastening elements (3) is retained. 15. Transmission system comprising a flywheel (1), a clutch disc and a clutch subassembly according to one of the preceding claims. 16. A method of assembling a transmission system for a motor vehicle comprising a flywheel (1) provided with threaded bores (10) and a clutch mechanism provided with a cover (2) itself provided with through holes (20) which are secured by means of fastening elements (3) having 5 at least one threaded end portion (31) introduced into the through holes (20) of the cover (2) then screwed into the threaded bores (10) of the flywheel (1), characterized in that a pre -assembly of the fastening elements (3) on the cover (2) by providing said orifices (20) with retaining elements (21, 4, 5) cooperating with at least the end portion 10 threaded (31) of said fastening elements to position them prior to their screwing in the threaded bores of the flywheel (1). 17. The assembly method according to claim 16, characterized in that a layer of encapsulated glue is deposited at least on the threaded end portion (31) of the fastening elements (3) after introduction of their end portion 15 threaded (31) in said retaining elements (21, 4, 5). 2/6