The invention relates to the field of decoupling pulleys.

Such a pulley is proposed for example in EP 0980479 (D1).

This pulley is shown in Figure 1, in a longitudinal sectional view.

The pulley P comprises a rim J and a hub H which can be coupled to one another via a RT torsion spring and one-way clutch, Inc mounted in series with the torsion spring RT.

RT torsion spring is constructed and arranged to transmit print rotational movements to the rim J, for example by a belt mounted on the rim and connected to a motor shaft, the hub M so that the hub M, which is example intended to be mounted on a shaft of an auxiliary device such as an alternator, can be driven in the same direction as the rim ( "coupling" mode).

The UE-way clutch is also constructed and arranged so that the hub M and hence, the shaft on which the hub is intended to be mounted rotatably to a speed greater than the speed of rotation of the rim J , particularly when the pulley is decelerated, for example due to engine deceleration ( "freewheel" mode).

Thus, and conventionally, in "coupling" mode, the engine torque pass through the belt, the rim J, the one-way clutch, Inc, which is then driven by friction with respect to the rim J, the RT torsion spring which is connected in series with the one-way clutch, Inc, the hub

M on which the RT torsion spring is mounted and which then comes into contact with a component C secured to the hub M and finally, the shaft on which the hub is mounted.

On the contrary, in "freewheel" mode, the one-way clutch disengages, Inc of the rim J and the torsion spring RT, in series with the one-way clutch is in the neutral position at zero torque.

A disadvantage of the pulley proposed in document D1 lies in the fact that the RT torsion spring can undergo deformation (radial expansion) very important in the "coupling" mode. Indeed, in this operating mode, the torque passes through the RT torsion spring without the radial expansion of the torsion spring, resulting from the application of torque is limited.

Also, it may happen that the radial expansion of RT torsion spring is such that the latter comes into contact with the one-way clutch, Inc. Indeed, in D1, the one-way clutch, Inc, which is placed in the receiving area for the belt is placed directly around the RT torsion spring.

This can make the device non-operational.

This problem is known and solutions to limit the radial expansion of the torsion spring have already been proposed.

Thus, not experience this problem, US 7

975 821 B2 (D2) proposes to implement an intermediate piece (reference 1 10 in Figure 2 of the document D2) between the torsion spring and one-way clutch.

The solution proposed in document D2, however, involves, at the receiving area of ​​the belt, a larger pulley diameter than the diameter of the pulley proposed in document D1.

This may be practical difficulties because the maximum acceptable diameter of the pulley at that belt receiving area, defined by the particular machine or motor vehicle manufacturers, does not allow its use in any application. This limits the démutiplication ratio obtained between the engine crankshaft and alternator. Practically, an effective diameter of 50 mm tooth area is impossible while it would be desirable. Therefore, this also limits the possibilities for the dimensioning of the spring the one-way clutch.

However, the torque transmitted between the rim and the hub also through the one-way clutch, it reduces all the possibilities for dimensioning of the one-way clutch.

An object of the invention is to provide a decoupling pulley implementing a one-way clutch and not having at least the aforementioned drawbacks.

To this end, the invention provides a decoupling pulley provided with a longitudinal axis, said pulley comprising:

- a rim comprising a first zone for receiving a belt connecting the rim to a first power transmission member, and a second zone situated in the axial extension, i.e. in the direction defined by the longitudinal axis of the pulley, of the first zone;

- a hub intended to be secured to a second power transmission member;

one of the power transmission members being driving and the other being carried out;

- a ring mounted in the second zone of the rim and around the hub, so that said ring is rotatable about said longitudinal axis relative to the rim and / or the hub;

- an elastically deformable element mounted between the hub and the ring;

- a one-way clutch having one end secured to the ring and whose remaining part is mounted both in the second zone of the rim and over the crown;

the pulley is such that the first region of the rim has an internal diameter, the second zone of the rim has an internal diameter, the internal diameter of the second area being larger than the inner diameter of the first zone.

The device may also have at least one of the following characteristics, taken alone or in combination:

- the pulley provides a cover fixedly mounted on the rim and in contact with the crown;

the one-way clutch is a spring, eg a helical spring with contiguous turns;

the end of the one-way clutch is housed in a slot in the ring, said pulley further including a wedge in the gap and adjacent to said end of the one-way clutch;

the elastically deformable element is a torsion spring centered on the hub;

the end of the one-way clutch is arranged in contact with one end of the torsion spring;

the pulley is such that the end of the torsion spring which is in contact with the one-way clutch is curved, relative to the rest, defining a generally cylindrical shape, said torsion spring and the end of the one-way clutch is contacting a side face of this bent end of the torsion spring;

the pulley is such that the end of the torsion spring which is in contact with the one-way clutch is not bent with respect to the rest, defining a generally cylindrical shape, said torsion spring and the end of the one-way clutch is brought end to end with this non-bent end of the torsion spring;

the pulley is such that the hub comprises at least one lug and the ring comprises at least one slot receiving said at least one hub pin, so that, in a relative rotation direction between the rim and the hub, the torsion spring engages the hub until said at least one hub pin abuts against one end of said at least one ring of light;

the pulley comprises at least one bearing located between the rim and the hub; said at least one bearing includes at least one face extending radially and in contact with the hub;

said at least one bearing is formed either by a plastics material selected from polyetheretherketone (PEEK), polyethylene terephthalate (PET), polyamide (PA) loaded into molybdenum disulfide (MoS 2 ) or polyamide (PA) in charge polytetrafluoroethylene (PTFE) or with

an inner metal layer or a metal alloy, covered by an outer layer loaded polytetrafluoroethylene (PTFE);

- the elastically deformable member is a body made of elastomer or thermoplastic elastomer;

- the pulley provided at least one bearing arranged between the hub and the rim, advantageously in the first zone of the rim.

The invention will be better understood and other objects, advantages and features thereof will appear more clearly from reading the following description which is made with reference to the following appended figures:

- Figure 2 shows a first embodiment of the invention in a longitudinal sectional view;

Figure 3 is an exploded view of the pulley shown in Figure 2;

Figure 4 is a perspective view and sectional view of the pulley shown in Figure 2;

Figure 5 is another perspective view of the pulley of Figure 2, according to a different section from that shown in Figure 4;

Figure 6 is another perspective view of the pulley of Figure 2 without the crown; Figure 7 is a sectional view of the pulley of Figure 2 shown in an analogous manner to the representation of Figure 4, but in another operating mode;

Figure 8 is a graph representing the evolution of the torque transmitted between the drive member (rim, for example) and the driven member (hub, in this example) according to an angular change between these same elements;

9 shows a second embodiment of a pulley according to the invention, in longitudinal section and in perspective;

- Figure 10 is an exploded view of the pulley shown in Figure 9;

Figure 1 1 shows a third embodiment of a pulley according to the invention, in longitudinal section and in perspective;

Figure 12 is an exploded view of the pulley shown in Figure 1 1;

13 shows a fourth embodiment of a pulley according to the invention, in longitudinal section and in perspective, without crown;

Figure 14 is an exploded view of the pulley shown in Figure 13;

Figure 15 is a front view in section of the pulley according to the first embodiment of the pulley according to the invention;

Figure 16 shows a one-way clutch of the pulley and a corner capable of being used in conjunction with the one-way clutch;

La figure 17 représente un cinquième mode de réalisation d'un poulie conforme à l'invention, dans lequel la couronne coopère avec une contre-couronne, selon une vue en coupe longitudinale ;

La figure 18 représente, selon une vue de face, la couronne de la figure 17 ;

La figure 19 représente, selon une vue de perspective arrière, la contre-couronne de la figure 17, destinée à coopérer avec la couronne de la figure 18 ;

La figure 20 représente, selon une vue de côté, un embrayage unidirectionnel susceptible d'être employé dans le cadre de l'invention ;

La figure 21 représente, selon une vue de côté, un autre embrayage unidirectionnel susceptible d'être employé dans le cadre de la l'invention ;

- Figure 22 shows, in a side view, yet another one-way clutch capable of being employed as part of the invention;

Figure 23 is an exploded view of a crown and a against-ring according to the fifth embodiment of a pulley according to the invention shown in Figure 17, with a one-way clutch according to Figure 22; and

- Figure 24 is a perspective view inverted with respect to that of Figure 23.

A first embodiment of a pulley 100 according to the invention is shown in different views in Figures 2-7.

The decoupling pulley 100 according to the invention comprises a rim 1 to be secured to a first power transmission member (not shown, e.g. a belt connected to a shaft of a vehicle engine, which would be the leading case). The rim 1 is provided with a first zone 1 1 for receiving for receiving a belt, in this case a typical poly V® belt, to make the connection between the rim 1 and the first power transmission element. The rim 1 is also provided with a second zone 12 located in the axial extension, i.e. in the direction defined by the longitudinal axis AX of the pulley 100, the first area 1 1.

Advantageously, the second zone 12 of the rim 1 has an internal diameter D12 larger than the inner diameter of the first zone 1 1 of the rim 1.

The pulley 100 also comprises a hub 2 designed to be secured to a second power transmission member (e.g., a shaft of an alternator, which is in this case conducted) and having, in this first embodiment, the least one lug 21, 22, 23 is advantageously axially extending (longitudinal axis AX in FIG 2).

One of the power transmission elements is leading and the other is conducted.

The pulley 100 also comprises a ring 3 mounted in the second zone 12 of the rim 1 and around the hub 2. Also, the ring 3 is mounted within the pulley 100, so that it can rotate about the longitudinal axis AX, relative to the rim 1 and / or relative to the hub 2. This rotational movement will be explained in more detail in the following description. In this first embodiment, the ring 3 further comprises at least one lumen 31, 32, 33 receiving said at least one lug 21, 22, 23 of the hub 2. The or each lumen 31, 32, 33 has two ends 310 31 1; 320, 321; 330, 331 adapted to serve as an abutment for the corresponding lug 21, 22, 23 of the hub 2, according to the mode of operation of the pulley 100.

The pulley 100 is also provided with an element 4 is elastically deformable, in this case in this first embodiment, a torsion spring 4.

This torsion spring 4 is mounted between the hub 2 and the rim 3. More specifically, the torsion spring 4 is centered on the hub 2, the latter advantageously providing a peripheral groove 25 for receiving the torsion spring 4. To ensure its assembly between the hub 2 and the ring 3, the torsion spring 4 is preferably attached to both the hub 2 and the ring 3. The fastening of the spring 4 of torsion to the hub 2 and the ring 3 can s performing by a recess or by forms of restraint, provided in the hub 2 and the ring 3. for example, and as illustrated in the accompanying figures it can be observed that the end 41 of the torsion spring 4 is fitted into the ring 3 (fig. 5) and the other end 42 of the torsion spring 4 is fitted into the hub 2 (fig. 2).

The pulley 100 also comprises a one-way clutch 5, which is provided in this case for example in the form of a helical spring with contiguous turns.

This unidirectional clutch 5 is mounted inside of the rim 1. More specifically, the unidirectional clutch 5 comprises an end 51 fixed to the ring 3, for example by insertion or installation in an opening or slot 35 formed in the ring 3. The remaining portion 52 of the unidirectional clutch 5 is in turn mounted both in the second zone 12 of the rim 1 and above the crown 3.

Note that this part 52 has the general shape of a cylinder.

Advantageously, the other end (not visible in the attached figures) of the unidirectional clutch 5 is left free and is therefore fixed either to the ring 3 or to the rim 1. In this case, the unidirectional clutch 5 is selected so that in the natural state, the diameter of this one-way clutch 5 is larger than that of the rim 1, which allows to ensure prestressing of the one-way clutch 5 when it is inserted into the inner bore of the second zone 12 of the rim 1.

The end 51 of the unidirectional clutch 5 is advantageously and as shown in Figures 1 to 7 attached by an arm. This end or arm 51 is advantageously in contact with the end 41 of the torsion spring 4, to provide improved transmission of torque. Specifically, the end 41 of the torsion spring 4 which is in contact with the one-way clutch 5 is bent relative to the remainder of the torsion spring, said rest defining a generally cylindrical shape. Therefore the end 51 of the one-way clutch is in contact with a side face 410 of the curved end 41 of the torsion spring 4. This design is facilitated by the presence of a bend 53 of the arm 51. In practice, the curved end can s' extend substantially radially. This particular design facilitates mode "coupling, working in the closing spring 4 against torsion the wall 27 of the hub 2.

It should be noted that advantageously, provision may be a corner 60 located in the slot 35 of the ring 3 and next to the end or arm 51 of the one-way clutch 5. This corner 60 facilitates maintaining the arm 51 in place in the torque transmission. Such area 60 is visible in particular in Figures 2 and 4 and Figure 16 is a fragmentary exploded view showing the one-way clutch 5 and the wedge 60 (the latter not having been shown in Figure 3 ). The corner 60 helps to hold the arm 51 in the slot 35 provided in the ring 3 to receive the arms 51. In particular, it avoids the buckling of the arm 51 when the couple pass.

It is understood that the unidirectional clutch 5 is mounted in series with the torsion spring 4, via the ring 3 which holds the contacts.

Advantageously, and as illustrated in Figures 1 to 7 attached, in particular Figures 2, 3 and 4, the pulley comprises at least one bearing 6, which is provided for example in the form of a cylindrical ring, interposed between the hub 2 and the rim 1. The bearing 6 then serves as a guide to the hub 2 and replaces one or more bearings, especially cumbersome in the case of an implementation of a spring 4 of twist. Said at least one bearing 6 advantageously comprises a face 61 extending radially and in contact with the hub 2. This face 61 facilitates the assembly and holding in place the bearing 6. Furthermore, the bearing 6 may be made of a material plastic selected from polyether ether ketone (PEEK), polyethylene terephthalate (PET),) Or polyamide (PA) loaded polytetrafluoroethylene (PTFE). Alternatively, the bearing 6 can be achieved with a metallic inner layer or metal alloy, covered by an outer layer loaded polytetrafluoroethylene (PTFE).

The pulley 100 finally comprises a cover 8 which is associated a sealing plug 9. The hood 8 is intended to cover the rim 1 at the second region 12 of the rim 1, and is fixed to the rim 1. Advantageously and as shown in Figures 2-7 attached, the cover 8 is mounted in contact with the ring 3, and more precisely in contact with the side face 37 of the ring 3, which faces the cover 8. The pulley 100 includes finally, a seal 10 coming in a lateral opening of the rim 1, the side opposite the cover 8.

We will now describe the operation of the pulley 100 in this first embodiment of the invention.

At rest, that is to say when the elastically deformable element 4, for example a torsion spring is not biased, the pulley

100 is present in the configuration shown in Figure 5.

If the pulley 100, more specifically the rim 1 is rotated by a belt for example, connected to a motor (typical case: engine acceleration phase), the rim 1 is then rotated, by convention, in the direction schedule.

La mise en rotation de la jante 1 provoque l'expansion radiale de l'embrayage unidirectionnel 5 qui vient alors exercer un effort radial contre l'alésage interne de la jante 1 . La jante 1 entraîne alors, par frottement, l'embrayage unidirectionnel 5 en rotation. L'embrayage unidirectionnel 5 étant par ailleurs connecté à la couronne 3, cette dernière va également être entraînée en rotation. Dans la mesure où l'embrayage unidirectionnel 5 est monté en série avec le ressort 4 de torsion par l'intermédiaire de la couronne 3, le ressort 4 de torsion va également se refermer et ainsi provoquer l'entraînement du moyeu 2 dans le sens de rotation de la jante 1 .

Lors de la fermeture du ressort 4 de torsion sur le moyeu 2 et plus précisément sur la paroi 27 du moyeu 2, la position relative entre la couronne 3 (ou la jante 1 , cela revient au même) et le moyeu 2 évolue depuis la position représentée sur la figure 5 vers la position représentée sur la figure 7. En d'autres termes, la ou chaque lumière 31 , 32, 33 de la couronne 3 se déplace alors par rapport à le ou chaque ergot correspondant 21 , 22, 23 du moyeu 2. En pratique, la position relative entre la couronne 3 et le moyeu 2 dépend de la valeur du couple transmis. Ainsi, la ou chaque lumière 31 , 32, 33 peut se déplacer, par rapport à l'ergot correspondant 21 , 22, 23 sur un angle inférieur à l'angle maximal alpha 1 (a1 ) défini entre les deux extrémités 310, 31 1 , 320, 321 , 330, 331 opposées de la lumière 31 , 32, 33 correspondante (à la largeur de l'ergot près). La ou chaque lumière 31 , 32, 33 peut aussi se déplacer jusqu'à une mise en butée entre les ergots 21 , 22, 23 et l'extrémité opposée 31 1 , 321 , 331 de la ou chaque lumière 31 , 32, 33, c'est-à-dire jusqu'à cet angle maximal alpha 1 (a1 ), comme cela est effectivement représenté sur la figure 7. Cette mise en butée, obtenue par la présence de la ou chaque butée 21 , 22, 23 de moyeu 2 et les lumières 31 , 32,

33 correspondantes de la couronne 3 limite la déformation radiale du ressort 4 de torsion. En effet, lorsque cette mise en butée est atteinte, le surcroit de couple passe de la couronne 3 vers le moyeu 2 par la ou chaque butée. Cette conception permet, notamment pour des applications où les couples à transmettre sont particulièrement importants, d'améliorer la durée de vie du ressort 4 de torsion et donc de la poulie 100.

On notera que l'angle alpha 1 est représenté sur la figure 15, laquelle est une vue de face de la poulie 100 selon le premier mode de réalisation, dans la position correspondante à celle de la figure 5.

La figure 8 représente le couple transmis entre la jante 1 et le moyeu 2 de la poulie 100 en fonction d'une évolution angulaire entre ces mêmes éléments. La référence (angle nul) correspond à la position de repos de la poulie (fig. 5).

Sur cette figure 8 (pas à l'échelle), le fonctionnement décrit correspond aux angles négatifs ou nul. Le couple initial (angle nul) présente une valeur Co (non nulle) qui est liée à la présence du palier 6 qui apporte un léger frottement contre le moyeu 2. Puis, on a une montée du couple, selon une droite, qui traduit l'engagement du ressort 4 de torsion avec le moyeu 2. Et si la ou chaque butée 21 , 22, 23 arrive contre l'extrémité opposée 31 1 , 321 , 331 de la lumière 31 , 32, 33 correspondante (figure 7), le surcroit de couple transmis entre la jante 1 et le moyeu 2 passe par la couronne 3, à l'angle défini par la valeur alpha 1 (ai ).

Tout ce qui précède sur le fonctionnement de la poulie 100 selon le premier mode de réalisation de l'invention concerne le mode « couplage ».

Si la jante 1 décélère (par exemple si le moteur l'entraînant décélère), alors cela provoque la contraction radiale de l'embrayage unidirectionnel 5, ce qui stoppe tout passage de couple entre la jante 1 et l'embrayage unidirectionnel 5 et donc vers le moyeu 2. Le moyeu 2 est alors en survitesse par rapport à la jante 1 , mais également par rapport à la couronne 3, ce qui provoque l'expansion radiale du ressort 4 de torsion qui retourne vers sa position d'équilibre (figure 5 ; absence de sollicitation) et, dans le même temps, le ou chaque ergot 21 , 22, 23 de moyeu 2 retourne en direction de sa position de la figure 5.

Une fois la position de la figure 5 atteinte, on se retrouve alors à l'angle de valeur nulle (figure 7). Le couple est alors à la valeur Co, pour les raisons expliquées précédemment.

Cependant, si la survitesse du moyeu 2 est suffisamment importante, le moyeu 2 va alors entraîner la couronne 3 en survitesse par rapport à la jante 1 et donc également par rapport au capot 8 qui est monté fixe sur la jante 1 et au contact de la face 37 de la couronne 3. L'effort de contact entre la couronne 3 et la capot 8 est généré par une précontrainte axiale du ressort 4. Cette précontrainte peut être modulable en fonction du niveau Ci souhaité. Ce contact implique alors entre le capot 8 et la couronne 3 un frottement qui fait passer le couple de la valeur C0 à la valeur Ci (|C1 |> CO, du fait que le frottement capot/couronne s'ajoute au frottement moyeu/palier). Il convient de noter que l'entraînement s'effectue alors par la liaison entre le ou chaque ergot 21 , 22, 23 et l'extrémité 310, 320, 330 de la lumière 31 , 32, 33 correspondante, sans passer par le ressort 4 de torsion. Le frottement entre le capot 8 et la couronne 3 permet alors de décélérer plus rapidement le moyeu 2. Ceci est particulièrement intéressant car la survitesse du moyeu 2 par rapport à la jante 1 génère des phénomènes de bruyance que l'on peut ainsi limiter.

Tout ce qui précède dans le cas d'une décélération de la jantel concerne donc le mode « roue libre ».

Compte tenu de ce qui précède, il convient de noter que le frottement entre le capot 8 et la couronne 3 n'intervient que dans le mode « roue libre ». En effet, dans le mode « couplage », la couronne 3 est entraînée par la jante 1 , si bien qu'il n'y a pas de vitesse relative entre le capot

8 et la couronne 3. Ce frottement est donc mis à profit lorsqu'il est utile, à savoir en mode « roue libre » pour améliorer la décélération du moyeu 2, la survitesse du moyeu 2 générant des phénomènes de bruyance qu'on cherche à limiter. Par ailleurs, en mode « couplage », l'absence de déplacement relatif entre le capot 8 et la couronne 3 évite des pertes mécaniques par frottement.

En revanche, le frottement entre le moyeu 2 et le palier 6 advient quel que soit le mode de fonctionnement de la poulie, mode « couplage » ou mode « roue libre ».

On notera toutefois que, dans le cadre de l'invention, le fait que la face latérale 37 de la couronne 3 soit au contact du capot 8 n'est pas obligatoire.

Nous allons maintenant décrire une poulie 100' selon un deuxième mode de réalisation conforme à l'invention, à l'appui des figures 9 et 10 (le joint d'étanchéité 10 n'est pas représenté sur ces figures, mais présent ; de même sur la figure 10 seulement le coin 60 n'est pas représenté mais est présent sur la figure 9, ce coin 60 se présentant, lorsqu'il est avantageusement prévu comme représenté sur la figure 16).

Dans ce deuxième mode de réalisation, des références identiques se réfèrent à des éléments identiques à ceux du premier mode de réalisation.

Le deuxième mode de réalisation se distingue du premier mode de réalisation par la conception du moyeu et de la couronne.

En effet, dans ce deuxième mode de réalisation, la poulie 100' comporte un moyeu 2' qui ne nécessite pas d'ergots et en conséquence d'une couronne 3' qui ne nécessite par de lumières correspondantes. Les figures 9 et 10 présentent en effet un moyeu 2' sans ergots et une couronne 3 sans lumière.

En conséquence, dans ce deuxième mode de réalisation, il n'est pas prévu de mise en butée à un angle maximal, nommé alpha 1 pour le premier mode de réalisation, pour assurer un passage de couple, en mode

"Coupling" directly between the ring 3 'and the hub 2' without passing through the torsion spring 4.

Indeed, such abutment is not required for certain applications where the torque transmitted between the rim 1 and the hub 2 'is limited.

In this second embodiment, in "freewheel" mode, the friction torque between the cover 8 and the ring 3 passes directly over the torsion spring 4. This results in a setting opening of the spring.

For the rest, the design of the pulley 100 'is identical to that of the pulley 100 of the first embodiment. This is particularly the case of the unidirectional clutch 5 and optionally the corner 60 shown in Figure 16. This is also the case of the Preferred but not required design placed in contact with the crown 3 'against the cover 8 and the choice of different materials, for example for the bearing 6. accordingly, the block diagram of the 100 'pulley corresponds to that of Figure 8, with the exception of the torque rise (vertical line) in the angle alpha 1 which does not exist in this second embodiment.

We will now describe a third embodiment, in support of Figures 1 1 and 12, a 100 "pulley according to the invention (the sealing gasket 10 is not shown in these figures, but this ).

In this third embodiment, the elastically deformable element is a spring 4 of twist.

Indeed, the torsion spring is replaced by a body 4 "elastomer or thermoplastic elastomer.

Due to this design, the hub 2 'has a suitable shape to receive the body 4 "elastomer or thermoplastic elastomer, by gluing or overmolding. Furthermore, this body 4 "elastomer or thermoplastic elastomer may be attached to the ring 3" by gluing or overmolding. The one-way clutch 5 may be the same as the first embodiment as the second embodiment, including the existence of an end, for example in form of an arm 51, which is fixed in the ring 3 and advantageously a corner 60 as described in Figure 16 (the arm 51 and the wedge 60 are not visible in figures 1 1 and 12, due to the cutting plane chosen for these figures).

In this case however, the arm end has not to be in contact with the body 4 "elastomer or thermoplastic elastomer and is therefore

simply accommodated in the ring 3. There is also provided a bearing 6 "mounted between the hub 2 'and the rim 1 for guiding in rotation of the hub 2'. The bearing 6" is then advantageously arranged in the first zone 1 1 of the rim 1, due to the place left free by the absence of a torsion spring 4. the presence of a bearing 6 is no longer necessary due to the presence of the bearing 6 ". also note that, analogously to the second embodiment, the hub 2 "has no lugs and the ring 3" does not, accordingly, lights to receive such pins.

Functionally, the third embodiment does not involve maximum deflection angle a1 "coupling" mode. The torque value Co is no longer linked to slight friction bearing / hub, but to the residual friction in the bearing 6 ". For the rest, the pulley 100 'operates identically to the pulley 100. In particular, the body 4 "works, that is to say elastically deforms in the negative angle zone of Figure 8 and is not applied in areas of positive angles. Moreover, the couple Co-match the contribution of the friction between the cover 8 and the ring 3, when the side face 37 of the latter is mounted in contact with the cap 8.

We will now describe a fourth embodiment of a pulley according to the invention, in support of Figures 13 and 14.

In these figures, the fourth embodiment is shown as a variant of the first embodiment.

In this fourth embodiment, the torsion spring no longer works in the closed in the "coupling" mode, but the opening.

In this case, the hub 2 has the peripheral groove 25, so that when the torsion spring 4 'working opening, it can come against the inner wall 26 of the peripheral groove 25 which is radially outermost in the peripheral groove 25 and belonging to the hub 2.

In this case, it also results in the absence of end 41 bent relative to the remainder of the torsion spring. The

torsion spring 4 'therefore here has a generally cylindrical shape. In other words, the end 41 'of the spring 4' twist which is in contact with the one-way clutch 5 is not bent in relation to the rest, defining a generally cylindrical shape, said spring 4 'twist. The contact between the end of arm 51 of the one-way clutch and the end 41 'of the torsion spring 4' therefore no longer done by keeping the end of the arm 51 against a side face 410 of the end 41 of the torsion spring 4 as illustrated in Figure 5 (first embodiment), but by butting of the end 51 of the one-way clutch with this non-curved end 41 'of the spring 4' twist. This design facilitates, in "coupling" mode, the opening of the spring 4 'twist against the wall 26 of the hub 2. As a result of this design, the torsion spring 4 is simplified in its execution. The one-way clutch 5 can be the same as the first embodiment and a wedge 60 can then be viewed in the same implantation conditions.

More generally, everything else is the same.

It should be noted that the fourth embodiment is also applicable as an alternative to the second embodiment.

There is shown in Figure 17, a longitudinal sectional view of a fifth embodiment of the invention. This figure 17 shows the Figure 4 example with a against-ring 300 cooperates with the ring 30.

The crown against 300 performs the same function as the corner 60. The crown against 300 replaces the corner 60. Everything else is identical with respect to the illustration in Figure 4 and is not referenced in the figure 17.

This crown against 300 present, however, for some applications, advantages over the use of the corner 60. Indeed, the mounting of the end 51 of the one-way clutch is easier with the use of cons -crown 300. Furthermore, its use limits deformation of the ring 30 when mounting the end 51 of

way clutch in the ring 30 because, unlike the wedge 60, there is no need to go force in the crown.

In Figure 18, there is shown, according to a front view of the ring 30 and in Figure 19, against the crown 300 according to a rear perspective view. Here, the ring 30 comprises two lights L1, L2 for receiving a corresponding lug E1, E2 of the against-ring 300. Once the ring 300 against-installed in the ring 30, no possible movement therebetween is possible. The attachment may for example be effected by ultrasound where, in particular, the ring 30 and against-ring 300 are made of a plastic material. Of course, there can be other methods of attachment (snap, collage ...). In Figure 18, there is also the presence of a housing 350 for receiving the end 51 of the one-way clutch and another for housing 360, meanwhile, receiving the torsion spring 4. Generally, the against-ring 300 has a shape complementary to the ring 30.

Il convient de noter que l'embrayage unidirectionnel 5 peut être conçu de différentes façons.

Généralement, l'embrayage unidirectionnel 5 se présente sous la forme d'un ressort hélicoïdal, de préférence à spires jointives.

Ce ressort hélicoïdal peut se présenter par ailleurs et classiquement, sous la forme d'un cylindre. En effet, classiquement, et mis à part l'extrémité 51 , toutes les spires présentent un même diamètre. C'est ce que l'on peut voir par exemple, avant montage complet de la poulie conforme à l'invention (i.e. avant que le ressort d'embrayage ne soit contraint par les autres composants de la poulie), sur les figures 3, 10, 12, 14 ou 16.

Cependant, d'autres formes peuvent être envisagées, formes qui procurent certains avantages par rapport à la forme cylindrique de ce ressort hélicoïdal.

En effet, l'embrayage unidirectionnel 5 fonctionne par friction. II faut donc, lorsque l'on souhaite faire passer du couple par l'embrayage éviter le glissement.

La forme cylindrique convient pour la plupart des cas.

Cependant, pour certaines applications, le couple devant être transmis est plus important et la forme cylindrique du ressort d'embrayage peut alors atteindre sa limite de glissement qui ne permet pas de faire passer du couple.

Le demandeur s'est rendu compte que des formes autres que la forme cylindrique pouvaient permettre de repousser la limite de glissement et ainsi fournir une poulie autorisant un passage de couple plus élevé, et ce sans augmenter le nombre de spires, ce qui est d'intérêt pour maîtriser l'encombrement.

Ainsi, la figure 20 représente un premier exemple d'embrayage unidirectionnel 5' se présentant sous la forme d'un ressort hélicoïdal à spires jointives qui n'est pas cylindrique (extrémité 51 ' toujours mise à part). En effet, sur cet exemple, les spires SP1 , SP2 et SP3 présentent un même diamètre. En revanche, la spire SP4 présentent un diamètre plus grand que les spires SP1 à SP3, la spire SP5 présente un diamètre plus grand que la spire SP4 et la spire SP6 présente un diamètre plus grand que la spire SP5. Avantageusement, et comme représenté sur la figure 20, l'évolution des diamètres des spires SP4, SP5 et SP6 se fait de manière constante. Autrement dit, on peut définir une droite D passant par un sommet S4, S5, S6 de chaque spire SP4, SP5, SP6. On peut aussi définir cette configuration par un angle a entre la droite D et la droite d passant par les sommets des spires SP1 , SP2 et SP3 (la droite d est parallèle à l'axe longitudinal de l'embrayage unidirectionnel 5'). L'angle a peut notamment être compris entre 5° et 10°, et par exemple de 7,5°.

De manière générale, la forme de ce ressort d'embrayage

(voir les lignes en pointillés) est définie par une première partie, cylindrique (en l'occurrence formée par les spires SP1 à SP3), dans le prolongement de l'extrémité 51 ' destinée à être fixée à la couronne, et une deuxième partie, tronconique (en l'occurrence formée par les spires SP4 à SP6), dans le prolongement de la première partie.

Avec cette conception, il est alors possible de monter le ressort d'embrayage 5' avec un serrage classique pour les spires SP1 à SP3 et de prévoir un serrage plus important pour les spires SP4 à SP6 et même, le cas échéant, un serrage d'autant plus important que le diamètre de la spire concerné est important. En augmentant ainsi le serrage sur les spires SP4 à SP6, on repousse la limite de glissement et on peut donc faire passer un couple plus important. Par ailleurs, cette conception ne pose pas de difficultés particulières, par rapport à un ressort cylindrique, lorsque a poulie fonctionne en roue libre. En revanche, cette conception rend cependant un peu plus difficile le montage de l'extrémité libre (celle qui est opposée à l'extrémité 51 ', non visible sur la figure 20) du ressort d'embrayage.

Ainsi également, la figure 21 représente un deuxième exemple d'embrayage unidirectionnel 5" se présentant sous la forme d'un ressort hélicoïdal, en l'occurrence à spires jointives, qui n'est pas cylindrique (extrémité 51 " toujours mise à part). En effet, dans cet exemple, la forme générale est celle d'un tonneau. Les spires extrêmes SP10, SP15 présentent donc les plus faibles diamètres et les spires centrales SP12, SP13, les plus grands diamètres. Les spires intermédiaires SP1 1 , SP14 présentent des diamètres supérieures à ceux des spires extrêmes SP10, SP15 mais inférieurs à ceux des spires centrales SP12, SP13.

Analogously to the design of Figure 20, the turns of larger diameter SP12, SP13 can be tightened more strongly compared to a case where the clutch spring is cylindrical. Here too, we therefore reject the slip limit, allowing to pass more torque. Furthermore, the free end of the clutch spring is then less stressed in the design of Figure 20, which does not involve any harmful effect on the ease of assembly. However, the design of Figure 21 gives the block a residual torque during the freewheeling that is not negligible.

22 shows a third example of unidirectional clutch 5 " 'is in the form of a helical spring, in this case with contiguous turns, which is not cylindrical (end 51"'

always apart). In this example, the spiral SP1 10 has a first diameter, the SP130 turns, SP140, SP150 and SP160 show a second and same diameter and the SP120 turn is an intermediate turn whose diameter evolved from the coil SP1 10 to the coil SP130. The second diameter is larger than the first diameter.

Generally, the shape of the clutch spring is defined by a first portion, frustoconical (in this case formed by the SP1 turns 10 and SP120) in the extension of the end 51 'intended to be secured to the ring, and a second portion, cylindrical (in this case formed by the turns SP130 to SP160), in the extension of the first part.

Compared to a helical spring, the design of Figure 22 makes it possible to push the slip limit. Moreover, as for a cylindrical design, it does not pose mounting challenges and presents no particular drawbacks when the pulley freewheels mode.

The latter design is particularly advantageous.

To give an example, we can consider a one-way clutch 5, which is in the form of a helical spring with contiguous turns, of cylindrical shape, intended to be placed in a pulley according to the invention, the diameter D12 = 58mm. It then provides a uniform clamping of 1 6mm. This means, incidentally, that the diameter of the clutch spring is, before mounting 59,6mm. Moreover, the unidirectional clutch 5 is here realized with a steel according to the standard EN10270-1 SH.

The rim 1 is itself made of steel AISI 1018 with as a contact surface with the one-way clutch, a nitriding to achieve superior 300HV0.1 hardness.

Analogously, to a one-way clutch 5 " 'according to Figure 22, and the same pulley D12 diameter = 58mm, is then provided, for the winding SP1 10, a clamping of 1 mm and for the turns SP130 to SP160, a clamping 2mm. These clamps then define

incidentally clamping the SP120 transitional thread turn. Moreover, the unidirectional clutch is here realized with a steel according to the standard EN10270-1 SH. The rim 1 is itself made of steel AISI 1018 with as a contact surface with the one-way clutch, a nitriding to achieve superior 300HV0.1 hardness.

In Figures 23 and 24, there is shown, the ring 30, against the crown 300 and a one-way clutch 5 " 'according to the design of Figure 22, before assembly.

Whatever the embodiment envisaged, a pulley according to the invention provides several advantages over the prior art.

Indeed, the fact of shifting axially the unidirectional clutch 5, 5 ', 5 ", 5"' to the first region 1 1 of the rim 1, thanks to a crown 3, 30 also offset axially and serving as a support mechanical way clutch gives more freedom in design.

This is especially true when the one-way clutch is located entirely in the second zone 12 of the rim 1 (absolutely not, even in part, in the first zone 1 1 of the rim 1) and / or when the crown 3, 30, 30 'is integrally located in the second zone 12 of the rim well (absolutely not, even in part, in the first zone 1 1 of the rim 1) and that the diameters D1 1 D12 are equal or the diameter D12 is greater (strictly) the diameter D1 1.

Thus, when a torsion spring 4 is used in the context of the invention, it frees a space between the hub 2 and the rim 1 which allows to insert a bearing 6. This avoids the use of one or more bearings (D1) in which, for lack of space in the radial space between the torsion spring and the clutch are mounted on the sides. This alleviates the pulley and generally reduces its axial size.

And also, when a body 4 "elastically deformable is used in the context of the invention, one can implement a rolling centered under the first region 1 1 of the rim 1 (receiving area of ​​the belt) for the whole Place is released without increasing the radius of the pulley at the Zone 1 1 of the rim and without generating a greater axial dimension.

Generally, the crown 3, 30 provides mechanical support to the unidirectional clutch 5, 5 ', 5 ", 5"' which can only be beneficial.

The crown 3, 30 also allows, by having ports therein, to allow a direct interaction with the hub of lugs to limit the deformation of the spring 4 of twist.

Moreover, the implementation of a ring able to move in rotation with respect to the rim 1 and / or, as the mode of operation, relative to the hub 2 is particularly interesting. Indeed, when this ring 3, 30 is in contact with the cover 8, a brake is ensured mode "freewheel" and "freewheel" mode only, so that braking is implemented only when necessary ( limit the noisiness, for example rotation of the ring 3 with the hub 2 when the latter is in overspeed with respect to the rim 1). Mode "coupling", which friction does not exist which improves the torque transfer without unnecessary wear the ring 3, 30 or the cap 8.

Furthermore, in the case where the second area 12 of the rim 1 has an internal diameter D12 larger than the inner diameter of the first zone 1 1 of the rim, it can implement a one-way clutch 5 whose diameter is larger than the one proposed in D1. This is particularly interesting because the couple might be transmitted through the one-way clutch 5, 5 ', 5 ", 5" is limited by its diameter. In the context of the invention, we can implement a one-way clutch adapted to pass higher torques. Incidentally, for a given pair on the one-way clutch, the tangential force applied thereto (friction with the rim 1) is then smaller than in the document D1.

The life of the one-way clutch 5, 5 ', 5 ", 5"' can not then being improved.

CLAIMS

1. Pulley (100, 100 ', 100 ", 100"', 100 "") decoupling provided with a longitudinal axis (AX), said pulley comprising:

- a rim (1) comprising a first zone (1 1) for receiving a strap connecting the rim to a first power transmission member, and a second zone (12) situated in the axial extension, i.e. in the direction defined by the longitudinal axis (AX) of the pulley, of the first zone (1 1);

- a hub (2, 2 ', 2 ") intended to be secured to a second power transmission member;

one of the power transmission members being driving and the other being carried out;

- a ring (3) mounted in the second zone (12) of the rim (1) and around the hub (2, 2 ', 2 ") so that said ring (3) is rotatable about said longitudinal axis, relative to the rim (1) and / or the hub (2, 2 ', 2 ");

- an element (4, 4 ', 4 ") deformable elastically mounted between the hub (2, 2', 2") and the crown (3);

- a one-way clutch (5) having one end (51) is secured to the crown (3) and the remaining part (52) is mounted both in the second zone (12) of the rim (1) and au above the crown (3);

the pulley being moreover such that:

- the first zone (1 1) of the rim (1) has an internal diameter (Du);

- the second zone (12) of the rim (1) has an internal diameter (D 12 ), the internal diameter (D 12 ) of the second zone (12) being larger than the inner diameter (Du) of the first zone (1 1).

2. Pulley (100, 100 ', 100 ", 100"', 100 "") according to claim 1, wherein there is provided a cover (8) fixedly mounted on the rim (1) and in contact with the ring ( 3).

3. Pulley (100, 100 ', 100 "', 100" ") according to one of the preceding claims, wherein the resiliently deformable member is a torsion spring (4, 4 ') centered on the hub (2) .

4. Pulley (100, 100 ', 100 "', 100" ") according to the preceding claim, wherein the end (51) of the unidirectional clutch (5) is arranged in contact with one end (41, 41 ') of the spring (4, 4') to twisting.

5. Pulley (100, 100 ', 100 "', 100" ") according to the preceding claim, wherein:

- the end (41) of the spring (4) of twist which is in contact with the one-way clutch (5) is bent in relation to the rest, defining a generally cylindrical shape of said spring (4) of twist; and

- the end (51) of the unidirectional clutch (5) is in contact with a side face (410) of this bent end (41) of the spring (4) from twisting.

6. Pulley (100 " ') according to claim 4, wherein:

- the end (41 ') of the spring (4) of twist which is in contact with the one-way clutch (5) is not bent with respect to the rest, defining a generally cylindrical shape of said spring (4) of twist; and

- the end (51) of the unidirectional clutch (5) is abutted with this non-curved end (41 ') of the spring (4') to twisting.

7. Pulley (100, 100 " ') according to one of claims 4 to 6, wherein:

- the hub (2) comprises at least one lug (21, 22, 23); and

- the ring (3) comprises at least one lumen (31, 32, 33) receiving said at least one lug (21, 22, 23) of hub (2);

so that, in a relative rotation direction between the rim (1) and the hub (2), the torsion spring (4, 4 ") engages the hub (2) until said at least a lug (21, 22, 23) of hub (2) abuts against a

end (31 1, 321, 331) of said at least one lumen (31, 32, 33) of ring (3).

8. Pulley (100, 100 ', 100 ") according to one of claims 4 to 7, comprising at least one bearing (6) between the rim (1) and the hub (2).

9. Pulley (100, 100 ', 100 ") according to the preceding claim, wherein said at least one bearing (6) has at least one face (61) extending radially and in contact with the hub (2, 2' ).

10. Pulley (100, 100 ', 100 ") according to one of Claims 8 or 9, wherein said at least one bearing (6) is achieved either by a plastics material selected from polyetheretherketone (PEEK), polyterephthalate ethylene (PET), polyamide (PA) loaded into molybdenum disulfide (MoS 2 ) or polyamide (PA) loaded polytetrafluoroethylene (PTFE) or with a metallic inner layer or metal alloy, covered by an outer layer charged with polytetrafluoroethylene (PTFE).

January 1. Pulley (100 ") according to one of claims 1 or 2, wherein the resiliently deformable member is a body (4") made of elastomer or thermoplastic elastomer.

12. Pulley (100 ") according to the preceding claim, wherein there is provided at least one roller (6") arranged between the hub (2 ") and the rim (1), advantageously in the first zone (1 1) of the rim (1).

13. Pulley (100, 100 ', 100 "') according to one of the preceding claims, wherein the end (51) of the unidirectional clutch (5) is accommodated in a slot (35) of the ring (3 ), said pulley further comprising a wedge (60) located in the slot (35) and adjacent said end (51) of the unidirectional clutch (5).

14. Pulley (100 "") according to one of claims 1 to 12, comprising a against-ring (300, 300 ') cooperating with the ring (30, 30'), e.g., at least through openings ( L1, L2) provided in the ring and lugs (E1, E2) provided in the against-ring.

15. Pulley (100, 100 ', 100 ", 100"', 100 "") according to one of the preceding claims, wherein the one-way clutch (5) is a helical spring, for example with contiguous turns.

16. Pulley (100, 100 ', 100 ", 100"', 100 "") according to the preceding claim wherein the helical spring, for example with contiguous turns, presents a shape selected from:

- a cylindrical shape;

- a form comprising a first portion, cylindrical, in the extension of its end (51) attached to the ring and a second portion, frusto-conical, in the extension of the first portion;

- a barrel shape; or

- a form comprising a first portion, frusto-conical, in the extension of its end (51) attached to the ring and a second part cylindrical in the extension of the first part.