EP1691068A1 - Apparatus for starting an internal combustion engine - Google Patents

Abstract

The device has an overrunning clutch (30) selectively coupling in rotation a pulley (80) and an output shaft (12). The clutch is integrated in a central hole of the pulley and is axially fixed. The clutch has a driver (300) and a coaxial cylindrical groove (303) respectively coupled in rotation to the pulley and shaft. The driver is engaged with the pulley in a continuous manner.

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to a starter device, also called a starter, for driving a heat engine, also called an internal combustion engine, particularly a motor vehicle, by means of at least one belt or a chain and at least one pulley, as described in the French patent application FR 2 858 368 according to the preamble of claim 1 and shown in Figures 1a and 1b appended.

STATE OF THE ART

The starting device 10 (FIGS. 1a, 1b) comprises an output shaft 12 or drive shaft, which is intended to be rotated by the armature shaft 14 of an electric motor 16, here by the intermediate of two reduction gears planetary gear before 19, also called first reducer, and rear 18, also called second reducer, cascaded or series so that their reduction rate is increasing.

The shafts 12 and 14 are coaxial with axis X1.

The rear free end 20 of the output shaft 12 is guided in rotation by a rear bearing 24, with the interposition of a guide sleeve 25.

A movable assembly 28 includes a rear freewheel 30 which drives a front gear 32. The movable assembly 28 is mounted to slide axially on a splined intermediate section 34 of the output shaft 12 so as to be integral with the latter in rotation.

The first gearbox 19 (FIG. 1b) comprises a set of satellites 36 whose axes of rotation 38 are borne by a flange 40 of transverse orientation, perpendicular to the axis X1, which is integral in translation and in rotation with the end 20 of the shaft 12 and which is fixed on the latter by crimping.

The satellites 36 are immobilized axially in translation by a plate 42 force-fitted on the axes 38 of the satellites 36.

This gear 19 also includes a ring gear 44, which is made in one piece with an outer axial annular skirt 33 fixed in the casing or housing 48 of the starter 10. This ring 44 has at the front a bottom (not referenced ) in the form of a flange of transversely oriented transverse orientation for passage of the shaft 12. The sleeve 25 is between the outer periphery of the shaft 12 and the inner periphery of the flange of the ring 44.

The satellites 36 mesh with splines 50 carried by a front section 52 of the output shaft 13 of movement of the second rear gearbox 18.

The free end 59 before the shaft 13 is guided in rotation in a blind axial bore 57, which is formed in the rear face of the rear free end 20 of the shaft 12 with the interposition of a guide sleeve 63 This front end 59 is keyed in translation forward by a wedging ball 60 which is housed in the bottom of the bore 57.

The second reducer 18 is similar to the first gear 19 and comprises a set of satellites 37 whose axes of rotation 39 are carried by a flange 41 of transverse orientation, which is integral in translation and in rotation with the output shaft 13 movement and which is fixed on the latter by crimping.

The satellites 37 are immobilized axially in translation by a plate 43 force-fitted on the axes 39 of the satellites 37.
This gear 18 also comprises a ring gear 45, which is made in one piece with an outer axial ring skirt 31 fixed in the casing or housing 48 of the starter 10. This ring has a cross-shaped perforated flange bottom with interposition radial of a guide sleeve between the inner periphery of the bottom of the ring 45 and the outer periphery of the shaft 13.

The satellites 37 mesh with splines 51 carried by a front section 53 of the armature shaft 14.

The free end 54 before the armature shaft 14 is guided in rotation in a blind axial bore 56 which is formed in the rear face of the rear free end of the shaft 13 with the interposition of a guide sleeve. 58. This front end 54 is wedged in translation forwards by a wedging ball 61 which is housed in the bottom of the bore 56.

The starter 10 also comprises an electromagnetic contactor 62 (FIG. 1a), known per se in the field of motor vehicle starters, provided with a movable magnetic core 64 whose displacements are caused by a coaxial annular winding or winding 65, also solenoid, of axis X2 parallel to the axis X1. This core controls the axial displacement of the moving element 28 by means of a lever 66 which is pivotally mounted about an intermediate axis Y orthogonal to the axes X1 and X2. The casing 48 carries the switch 62 extending over the electric motor.

The movable core 64 acts on the upper end 68 of the lever 66, as it moves backwardly driven by the solenoid 65, so as to cause a corresponding axial rearward motion. forward of the lower end 70 of the lever 66 which is here shaped fork to act on the crew 28.

The solenoid 65 is supplied with electrical current to cause both the axial displacement of the moving element 28 forward and the starting of the electric motor 16 by means of a movable contact (not referenced) actuated by the mobile core 64.

For more details we refer for example to the document FR A 2 795 884, which describes in particular the movable contact, the spring teeth against teeth, the return spring and the fixed core of the contactor.

The electric motor 16, when electrically powered via the moving contact of the contactor, rotates the armature shaft 14, which transmits this rotational movement to the output shaft 12 via the two consecutive reducers 18 and 19.

The casing 48, intended to be fixed on a fixed part of the vehicle, houses, except for a part of the contactor 62, all the components of the starter which, for the drive of an internal combustion engine also called engine thermal (not shown), comprises a grooved pulley 80 which is arranged outside the casing 48, and which is coaxial axis X1 with the drive shaft 12 whose front free end 22 is guided in rotation by the pulley 80 with the interposition of a front ball bearing 82 arranged inside the axial bore 84 which passes through the tubular body 86 of the pulley 80, whose front section is externally grooved 88 to receive a belt 89.

The rear portion 90 of the body 86 is of reduced diameter and is rotatably mounted in the housing 48 via a rear ball bearing 92 which is received in a concave housing 94 formed in a tubular open front end 96 of the housing 48.

The design of the pulley 80 and bearings 82 and 92 is such that the pulley 80 is fixed axially relative to the housing 48 along the axis X1.

The starter 10 thus comprises, from rear to front, an axial stack, of axis X1, consisting of the electric motor 16 with its armature shaft 14, the two consecutive reducers 18 and 19, the moving element 28 with freewheeling 30 and the movement output pulley 80.

The axial displacements towards the front of the mobile assembly 28, called launcher, with its front pinion 32 are limited by a front axial stop 110, which is here a rod mounted on the shaft 12 by an elastic ring 112 mounted in a groove 116 of the shaft 12.

To constitute a controlled coupling mechanism in rotation, or clutch, with the pinion gear 32, the rear portion 90 of the internal bore 84 of the pulley 80 is toothed internally with a group of teeth to form a ring gear internally 118 in which the pinion 32 with its complementary teeth 120 can penetrate axially from rear to front under the action of the force applied to the moving element 28 by the fork 70 of the lever 66.

Thanks to the coupling mechanism 32-118, it is possible to separate the pulley 80 in rotation from the free wheel 30 and therefore from the drive shaft 12 which therefore does not operate continuously for very long periods of operation and in a very restrictive environment such as that of a heat engine.

The freewheel 30 is of known general structure with cylindrical rollers 29 of the type commonly used in sprocket starters whose performance, qualities and reliability are well known. and adapted to the automotive context. Such a wheel is of reduced cost and requires only reduced lubrication.

Pinion 32, which constitutes the movement input element of the coupling controlled mechanism, has teeth radially outwardly projecting angularly distributed angularly.

The teeth 119 of the ring gear of the pulley 80 are complementary to the teeth 120, and they can all be chamfered at their axial ends to facilitate the axial insertion of the pinion 32 in the ring 118, that is to say the interconnection of the freewheel 30 and pulley 80.

When the supply of the linear actuator constituted by the switch 62 is cut off, the return spring 67 of the core 64 recalls the moving element 28, via the lever 66, axially towards the rear.

When the heat engine is started, the pulley 80 is permanently rotated at a speed of between 2,000 and 18,000 revolutions / minute, which is a function of the rotational speed of the engine, and the drive ratio via the belt 89 between the pulley of the engine. crankshaft of the engine and the pulley 80.

The pulleys and the belt therefore belong to a motion transmission device intervening between the crankshaft of the engine and the starting device called starter.

When the coupling clutch 32, 118 is disengaged, only the pulley 80 and the bearings 82 and 92 rotate continuously. The other coaxial components of the starter 10 are not rotated.

The electric motor 16 comprises a stator 161, a rotor 162 provided with a packet of notched laminations receiving the winding 163, a collector 164 with electrically conductive blades 165 connected to the winding 163, and brushes 166 held in contact with the blades 165 by resilient return members.

Here the housing 48 is divided into a front portion 481 and a rear portion 482 secured by tie rods 483, the skirts 31 and 33 and the stator 161 being axially stacked and held pressed against each other between the front 481 and rear 482 .

The skirts 31 and 33 have at their outer periphery indentations (not referenced) for complementary passage of the tie rods 483 so that they are immobilized in rotation by the tie rods 483. The rear portion 482 constitutes a guide bearing for a portion of rear free end 141 of the shaft 14.

FIG. 6 of this document FR 2 858 368 shows an embodiment in which the free wheel is fixed axially and is housed in the rear part of the pulley. This freewheel has a first coaxial portion belonging to a driver secured to the rear portion of the pulley.

These starter devices are satisfactory, however it may be desirable to decrease the length of the starter device.

Indeed, the presence of the moving element 28 and the need to provide it with sufficient axial travel to allow the pinion 32 to disengage itself completely from the ring gear 118, increase the length of the starting device or starter 10.

SUMMARY OF THE INVENTION

The present invention aims in particular to reduce the length of the starter device.

To this end, the invention proposes a starting device for driving a heat engine, in particular of a motor vehicle, via at least one belt or chain and at least one pulley, this device comprising an electric motor with an armature shaft, an output shaft intended to be rotated by the armature shaft of the electric motor via one or more speed reducers rotationally linking the output shaft to the armature shaft, and an axially fixed freewheel selectively rotating the pulley and the the output shaft, in which the freewheel is housed in an internal bore of the pulley and comprises two coaxial parts of common axis, a first of the coaxial parts belonging to a driver integral with the rear part of the pulley, characterized in that that the second coaxial portion is integral with a front section of the output shaft constituting the output shaft of an epicyclic gear speed reducer.

The invention takes advantage of the pulley and the output shaft which reduces the axial length of the starter device.

In addition to the previous embodiment can be removed meshing pinion 32 with the ring gear 118, so that the solution according to the invention is quieter.

In addition we can remove the lever and the moving element of Figure 1a and Figure 6 so that the output shaft is simplified since it is devoid of fluted section.

The contactor is also simplified because it has only one power supply function of the electric motor.

One can alternatively use another component to perform this function.

The casing of the device is simplified as well as the freewheel because it does not have an inner ring toothed internally.

In addition the coach belongs to the rear part of the pulley so that we take advantage of the material of the pulley.

The freewheel is housed in a central bore of the pulley to further increase the axial compactness of the starter device.

The starting device according to the invention, with a reduced number of parts, is thus less complex, lighter, less bulky axially and less expensive.

• Le dispositif comporte deux réducteurs de vitesse avant et arrière à train épicycloïdal montés en série, l'arbre de sortie constituant l'arbre de sortie de mouvement d'un réducteur de vitesse à train épicycloïdal avant, tandis que l'arbre d'induit est configuré à l'avant pour former le pignon solaire d'un réducteur de vitesse à train épicycloïdal arrière.
• Chaque réducteur de vitesse comportant une couronne à denture interne, est prévu une couronne unique commune aux deux réducteurs de vitesses et la couronne unique présente des moyens de blocage en rotation par rapport à un carter que présente le dispositif.
• Les parties coaxiales sont d'un seul tenant respectivement avec l'arbre de sortie et avec la poulie pour diminuer le nombre de pièces et rendre la solution plus économique.
• La deuxième partie coaxiale appartient à un tronçon cylindrique avant de l'arbre de sortie en sorte que la deuxième partie a une forme simple.
• La roue libre comprend un entraîneur pourvu d'une partie annulaire coaxiale à l'arbre, des logements creusés circonférenciellement dans une face radialement intérieure de la partie annulaire, une piste cylindrique disposée à l'intérieur de la partie annulaire, des éléments roulants disposés dans les logements, et des organes élastiques sollicitant les éléments roulants vers des premières extrémités circonférencielles respectives des logements, en sorte que la roue libre a une structure inversée par rapport à une roue libre conventionnelle.
• Le fond de chaque logement forme une rampe de profil tel que, quand l'entraîneur tourne plus vite que la piste, l'entraîneur et la piste sont libres en rotation l'un par rapport à l'autre et la roue libre ne transmet pas de couple, tandis que pour de faible différence de vitesse de rotation entre l'entraîneur et la piste les éléments roulants sont bloqués entre la rampe et la piste du côté de la première extrémité des logements et la roue libre transmet le couple de l'arbre de sortie à la poulie en sorte que le moteur électrique est ménagé et que la roue libre est fiable et que le coincement et le décoincement des éléments roulants sont réalisés de manière aisée.
• La roue libre peut comprendre des moyens pour maintenir les éléments roulants à distance de la piste quand l'entraîneur tourne à grande vitesse par rapport à la piste en sorte que les usures de la roue libre sont réduites et que la durée de vie de celle-ci est augmentée ainsi que sa fiabilité.
• Les éléments roulants peuvent être maintenus à distance de la piste par la force centrifuge quand l'entraîneur tourne à grande vitesse par rapport à la piste en sorte que les usures sont réduites et que l'on obtient un désaccouplement automatique entre l'entraîneur et la piste en fonction de la vitesse de rotation et ce de manière simple et économique.
• L'élément roulant peut être maintenu en équilibre en un point de la rampe sous l'effet combiné de la force centrifuge et de l'effort exercé par l'organe élastique quand l'entraîneur tourne à grande vitesse par rapport à la piste.
• La direction perpendiculaire à la tangente à la rampe audit point d'équilibre peut former un angle par rapport à la direction radiale passant par le centre de l'élément roulant tel que celui-ci est sollicité vers la seconde extrémité circonférentielle sous l'effet de la force centrifuge quand l'entraîneur tourne à grande vitesse par rapport à la piste.
• La raideur des organes élastiques et les profils des rampes peuvent être choisis pour que les éléments roulants roulent sur la piste quand l'entraîneur tourne par rapport à la piste à une vitesse inférieure à un seuil prédéterminé, ces éléments étant maintenus à distance de la piste pour une vitesse de rotation supérieure audit seuil.
• Le seuil prédéterminé peut être supérieur à 800 tours par minutes.
• Les éléments roulants peuvent être des galets.
• La roue libre est du type à embrayage conique.
• La roue libre peut être fixe axialement pour réduction de l'encombrement axial du dispositif de démarrage et réduction de la longueur de l'arbre de sortie.
• L'alésage central de la poulie présente une chambre avant qui reçoit un axe avant fixe ou une partie cylindrique axialement fixe, des moyens de palier intervenant entre la périphérie externe de l'axe avant ou de la partie fixe et la périphérie interne de la poulie (80).
• L'axe avant ou la partie fixe sont solidaire de la partie avant d'un carter que présente le dispositif.

The device described above may further comprise in combination one or more of the following features:

• The device comprises two series-connected front and rear speed reducers in series, the output shaft constituting the output shaft of a forward planetary speed reducer, while the armature shaft is configured at the front to form the sun gear of a rear epicyclic gearbox.
• Each speed reducer comprising a crown with internal teeth, is provided a single ring common to both gearboxes and the single ring has means for locking in rotation relative to a housing that presents the device.
• The coaxial parts are in one piece respectively with the output shaft and with the pulley to reduce the number of parts and make the solution more economical.
• The second coaxial part belongs to a cylindrical section before the output shaft so that the second part has a simple shape.
• The freewheel comprises a trainer provided with an annular portion coaxial with the shaft, recesses circumferentially recessed in a radially inner face of the annular part, a cylindrical track disposed inside the annular part, rolling elements arranged in the annular part. the housings, and elastic members urging the rolling elements to respective first circumferential ends of the housing, so that the freewheel has an inverted structure with respect to a conventional freewheel.
• The bottom of each housing forms a profile ramp such that, when the coach rotates faster than the track, the coach and the track are free to rotate relative to each other and the freewheel does not transmit torque, while for a small difference in rotational speed between the trainer and the track the rolling elements are blocked between the ramp and the track on the side of the first end of the housing and the freewheel transmits the torque of the shaft output to the pulley so that the electric motor is formed and that the freewheel is reliable and the jamming and unhooking of the rolling elements are performed easily.
• The freewheel may comprise means for keeping the rolling elements at a distance from the track when the trainer rotates at a high speed with respect to the track so that the wear of the freewheel is reduced and the service life of the latter is reduced. it is increased as well as its reliability.
• The rolling elements can be kept away from the track by the centrifugal force when the trainer rotates at high speed relative to the track so that the wear is reduced and that there is an automatic disconnection between the trainer and the track depending on the rotational speed in a simple and economical manner.
• The rolling element can be kept in equilibrium at a point of the ramp under the combined effect of the centrifugal force and the force exerted by the elastic member when the driver rotates at a high speed relative to the track.
• The direction perpendicular to the tangent to the ramp at said equilibrium point may form an angle with respect to the radial direction passing through the center of the rolling element such that it is biased towards the second circumferential end under the effect of the centrifugal force when the trainer rotates at a high speed relative to the track.
• The stiffness of the elastic members and the profiles of the ramps may be chosen so that the rolling elements roll on the track when the trainer rotates relative to the track at a speed below a predetermined threshold, these elements being kept at a distance from the track for a speed of rotation greater than said threshold.
• The predetermined threshold may be greater than 800 revolutions per minute.
• The rolling elements can be rollers.
• The free wheel is of the conical clutch type.
• The freewheel can be fixed axially to reduce the axial size of the starting device and reduce the length of the output shaft.
• The central bore of the pulley has a front chamber which receives a fixed front axle or an axially fixed cylindrical portion, bearing means intervening between the outer periphery of the front axle or the fixed part and the inner periphery of the pulley (80).
• The front axle or the fixed part are integral with the front part of a casing that the device has.

It will be appreciated, in the context of a freewheel with rolling elements, that the freewheel is formed since there is no longer any contact between the track and the rolling elements for the high speeds of rotation of the trainer relative to at the track.

This solution allows a permanent connection between the starting device and the heat engine.

In addition, the output shaft is simplified since the housings of the rolling elements are made in an annular portion integral with the pulley. The operation of the freewheel is therefore improved. In addition, the free wheel can easily hang up after each compression stroke of the engine.
The freewheel is safe operation in all cases and the electric motor is arranged.

BRIEF DESCRIPTION OF THE FIGURES

• la figure 1a est une vue en coupe axiale d'un dispositif de démarrage selon l'art antérieur,
• la figure 1b est une vue agrandie des réducteurs du dispositif de la figure 1a,
• la figure 2 est une vue partielle en coupe axiale d'un dispositif de démarrage conforme à l'invention,
• la figure 3 est une représentation graphique de l'intensité du courant consommé par le moteur électrique du démarreur de la figure 2 en fonction du temps, pendant le démarrage d'un moteur thermique,
• la figure 4 est une vue en coupe du dispositif de la figure 2, dans un plan perpendiculaire à l'axe de rotation du moteur électrique, considérée selon l'incidence des flèches IV de la figure 2,
• la figure 5 est une vue agrandie d'un détail V de la figure 4 montrant les efforts s'exerçant sur les galets de la roue libre sous l'effet de la force de centrifugation,
• la figure 6 est une vue en perspective de la roue libre de la figure 4,
• la figure 7 est une vue similaire à la figure 2, pour une variante de réalisation de l'invention et
• la figure 8 est une vue agrandie d'une variante de la couronne dentée de la figure 7.

Other characteristics and advantages of the invention will emerge clearly from the description which is given below, by way of indication and in no way limiting, with reference to the appended figures, among which:

• FIG. 1a is an axial sectional view of a starting device according to the prior art,
• FIG. 1b is an enlarged view of the gear units of the device of FIG. 1a,
• FIG. 2 is a partial view in axial section of a starting device according to the invention,
• FIG. 3 is a graphical representation of the intensity of the current consumed by the electric motor of the starter of FIG. 2 as a function of time, during the starting of a heat engine,
• FIG. 4 is a sectional view of the device of FIG. 2, in a plane perpendicular to the axis of rotation of the electric motor, considered according to the incidence of the arrows IV of FIG. 2,
• FIG. 5 is an enlarged view of a detail V of FIG. 4 showing the forces exerted on the rollers of the free wheel under the effect of the centrifugal force,
• FIG. 6 is a perspective view of the freewheel of FIG. 4,
• FIG. 7 is a view similar to FIG. 2, for a variant embodiment of the invention and
• FIG. 8 is an enlarged view of a variant of the ring gear of FIG. 7.

DETAILED DESCRIPTION OF AT LEAST ONE EMBODIMENT OF THE INVENTION

In the following description, reference is made to a front-to-back orientation, corresponding to the left-to-right orientation in FIGS. 1 and 2, and the invention illustrated in FIGS. 2 to 8 will be used to describe the invention. the same reference numerals as those used in the description of Figures 1a, 1b to designate identical parts or the same function.

The starting device of FIGS. 2 and 7 comprises an electric motor 16 with a shaft armature 14, driven in rotation by the electric motor 16 when the latter is electrically powered, an output shaft 12, front and rear gear shifters 18 and 18, and a free wheel 30 selectively rotating the pulley 80 and the output shaft 12.

The electric motor 16 comprises components 161 to 165 as in FIGS. 1a, 1b, its stator 161 and its brushes being in FIG. 2 of the type described in document FR A 2 726 701 and in FIG. that described in document EP A 0 794 194 to which reference will be made.

The gear reducers 19, 18, here with epicyclic gear train, are connected in series and rotate the output shaft 12 to the armature shaft 14.

Each of these reducers 19, 18 comprises a sun gear 52, 53 respectively provided with splines or teeth 50, 51, satellites 36, 37 mounted loosely about axes 38, 39 carried by a planet carrier 40, 41, a ring 44 , 45, 46 fixed toothed internally. The satellites mesh with the sun gear and the crown. Here a plate is fitted on the axes of the satellites. Alternatively the plates are removed and are replaced for example by a plurality of thrust washers mounted on the axes 38, 39.

The armature shaft 14 is configured at the front to form the sun gear 53 of the rear gearbox 18.

In FIGS. 2 and 7, the sun gear 52 of the front reduction gear 19 belongs to the output shaft 13 of the rear gearbox 18. This shaft 13 is integral with the rear of the rear gearbox 18, in the form of a flange of transverse orientation.

In Figure 2 this tree is full in the front and has the same configuration as that of Figures la and 1b. It thus presents at the back a blind hole for receiving the front end of reduced diameter of the armature shaft 14 with radial interposition of a guide sleeve (not referenced). At the front end of reduced diameter of the shaft 13 is received in a blind hole of the rear end of the output shaft 12 with radial interposition of a guide sleeve 63. The satellite door of the gearbox 18 is crimped to the rear end of the shaft 13.

In Figure 7 the satellite carrier 41 of the rear gear 18 is integral with the rear end of the rear gearbox output shaft 18. This shaft is coincident with the sun gear 52 of the front gear 19. This pinion 52 is traversed by the front portion 54 of reduced diameter of the armature shaft 14. In a variant, the planet carrier 41 is crimped on the rear end of the pinion 52.

In Figure 2 is provided for each gear 19, 18 a ring respectively 44, 45 with internal teeth. Each ring has at the front a flange of transverse orientation traversed respectively by the shaft 12 and the shaft 13 with the interposition of a guide sleeve between the outer periphery of the shaft concerned and the inner periphery of the associated flange .

In Figure 7 there is provided a single ring 46 common to the two reducers 18, 19 and devoid of flange so that the solution is more economical and less bulky axially.

The rings 44, 45, 46 are advantageously made of moldable plastic to reduce noise. They are in an embodiment of thermosetting plastic material. This plastic material is alternatively reinforced with fibers.

In these FIGS. 2 and 7, the output shaft 12 constitutes the output shaft of movement of the epicyclic gearbox before 19.

The pulley 80 has a body 86 with an axial inner bore 84.

It will be noted that, unlike the prior art, the bore 84 of the pulley 80 has in FIG. 2 an internal partition 841 perpendicular to the axis X1, dividing this bore into a cylindrical front chamber 842 of axis X1. and a cylindrical rear chamber 843 of X1 axis in which is housed the free wheel 30. It is the same in Figure 7 in which we did not refer to the partition and the rooms for simplicity.

Partition 841 is in one piece with the body of the pulley. In a variant this partition is attached to the body for example by means of a plurality of screws.

This partition is secured to the pulley.

As an alternative to Figure 7, the partition is distinct from the body of the pulley and belongs to the front portion 481 of the housing 48 described below.

Thus, according to a characteristic, the freewheel 30 is integrated in the central bore 84 of the pulley 80.

This free wheel 30 is in Figures 2 and 7 integrated in the rear portion 90 of the pulley 80.

This rear portion 90 is here ring-shaped.

This free wheel 30 is axially fixed which reduces the axial length of the starting device and spare the freewheel.

The front chamber 842 receives in FIG. 2 a front axle 21 having a threaded front end portion 211 projecting out of the bore 84 forward and received in a threaded hole 202 of a nose 204 which belongs to a radial extension 206 of the front portion 481 of the casing 48.

This axis 21 can be screwed from the inside.

As a variant, this axis is screwed from the outside, the threaded end then having at its front face an impression for a screwing tool of the axis 21.

Other modes of attachment are possible for example using complementary frustoconical shapes of the hole 202 and the axis 21 threaded at its free end to receive a nut bearing on the nose 204 via a bearing washer. At least one key can be provided to complete the locking in rotation.

In Figure 7 the housing 48 is extended forward by a nose 204 shaped as a fixed axial portion 221 cylindrical axis X1, around which the pulley 80 is mounted idle.

Preferably the nose 204 is in one piece with the front portion 481 of the housing. Alternatively it is reported on this front 481 for example by screwing or welding.

Ball bearings 82, mounted in the chamber 842, are interposed radially between the inner periphery of the pulley 80, delimiting the axial bore 84, and the outer periphery respectively of the front axle 21 (Figure 2) and the part fixed 221 (Figure 7).

These ball bearings 82 are identical unlike bearings 82, 92 of Figure 1b.

Alternatively the bearings 82 are replaced by a bearing with two rows of balls or by roller or needle bearings. Bearing means therefore intervene between the outer periphery of the front axle 21 or the fixed part 221 and the inner periphery of the pulley 80 defining the bore 84.
In FIGS. 2 and 7, the nose 204 is configured to house the pulley 80 therein. The nose has an opening for the passage of the belt 89 and is configured to present, in the lower part of FIGS. 2 and 7, a cavity delimited in part. by the outer periphery of the axis 21 or the fixed part 221. This cavity serves to accommodate the pulley 80 and the belt 89.
This cavity is open at the top of FIGS. 2 and 7 for passage of the motion transmission belt 89. The nose 204 is therefore of interrupted annular shape for the passage of the belt 89.

In FIG. 2, the nose 204 also houses the free wheel 30. The nose comprises an axially oriented bottom belonging to the front portion 481 of the casing 48. This bottom is extended at its front end by the extension 206 of the front end. radial orientation, that is to say of transverse orientation with respect to the axis X1.

This bottom is extended at its rear end by a rearward extension (not referenced) of radial orientation, that is to say of transverse orientation relative to the axis X1. This rear extend belongs to the front part 481.

The rear extension is provided with an opening, here circular, (not referenced) into which the output shaft 12 enters. This rear extension here is longer radially than the extension before 206, the axial distance between the two extensions depending on the width of the belt 89 and the freewheel 30.

It is the same in Figure 7 in which the rear portion 90 of the pulley passes through said opening of the rear radial extension of the front portion 481.

The freewheel 30 is in this case housed in the front part 481 and is separated from the front part of the pulley by the rear extension of the front portion 481.

This front part 481 is in FIGS. 2 and 7, advantageously made of moldable material, here based on aluminum and in a non-visible manner, with perforated lugs for fixing the starter device, for example using screws or bolts. , on a fixed part, such as the housing of the engine. This engine is in a fixed embodiment. Here the engine is that of a motor vehicle, such as a passenger vehicle or a motor boat. The front portion 481 differs from that of a conventional starter in particular by the nose 204 preferably molded with the front portion 481.

In FIG. 7, preferably the fixed portion 221 is integrally molded with the nose 204 and the front portion 481 of the casing 48. Specifically, the nose 204 is connected to the front portion 481 by at least one support arm, which is partially visible. in FIG. 2. As a variant, this part 221 is attached for example by screwing or welding on the nose 204.

This front portion 481 comprises in FIGS. 2 and 7 threaded-hole lugs, one of which is visible in FIG. 2, for screwing the tie-rods 483. The bearings 82 of FIG. 2 are housed in the front chamber 842 of FIG. the bore 84 and it is the same in Figure 7, the pulley 80 is thus mounted mad about the fixed axis 21 or the fixed portion 221. The output shaft 12 has in Figure 2 a portion of front end 121 of reduced diameter, through an orifice 844 formed in the center of the inner wall 841 and engaged in a blind hole 71 formed in a rear face of the axis 21, a guide sleeve 72 being interposed radially between the front part. 121 and the wall of the blind hole 71. The front portion 121 is wedged translationally forward by a ball 73 housed at the bottom of the blind bore 71.

The freewheel 30 comprises two coaxial parts of axis of symmetry X1.

According to the invention these coaxial parts are rotatably connected respectively to the pulley 80 and the output shaft.

In one embodiment the freewheel is conically clutch type of that described in WO 03/002870 and comprises a first frustoconical surface secured to the rear portion of the pulley extended to the rear for this purpose and a second surface frustoconical shape complementary to the first surface, integral with the output shaft 12. The first surface surrounds the second surface. There is thus formed a disengageable coupling device with a conical clutch between the output shaft 12 and the pulley 80. The angle of the cone depends on the applications as explained in FIG. 2 of the aforementioned document. The first surface belongs to a coach coaxial with the axis X1 and integral with the pulley 80, while the second surface is integral with the output shaft 12. The friction surfaces therefore belong to two coaxial parts rotatably connected respectively to the pulley 80 and the output shaft 12.

In one embodiment, the friction surfaces belong to a friction lining respectively fixed on the driver and on the shaft 12.

Alternatively, as shown in FIGS. 4 to 6, the freewheel 30 comprises a driver 300 provided with an annular portion 301 coaxial with the output shaft 12, housing 302 circumferentially hollowed in an axially oriented inner face or periphery. of the annular portion 301, a cylindrical track 303 coaxial with the shaft 12 disposed within the portion annular 301, rolling elements 29 disposed in the housing 302, and resilient members 305 urging the rolling elements 29 to respective first circumferential ends 306 of the housing 302.

The rolling elements 29 and the elastic members 305 therefore belong to the trainer.

The annular portion 301 of the driver 300 and the cylindrical track 303 constitute the two aforesaid coaxial parts respectively integral in rotation with the pulley 80 and the output shaft 12.

The rolling elements 29 are intended to cooperate with the outer periphery of the track 303.

Thus compared to the solution of FIGS. 1a and 1b, the driving and driven parts are reversed, the track belonging to the shaft and the driver to the pulley.

More precisely (FIG. 5) the bottom of each housing 302 forms a ramp 308 of profile such that, when the driver 300 experiences a torque transmitted by the track 303, so that the starting system drives the heat engine, the rolling elements 29 are blocked between the ramp 308 and the outer periphery of the track 303 on the side of the first end 306 and the free wheel 30 transmits the torque of the output shaft 12 to the pulley 80, and for a large torque transmitted by the In the starting system, the driver 300 and the track 303 are free relative to one another and the freewheel 30 does not transmit the torque between the pulley 80 and the output shaft 12.

Thus, when the electric motor is electrically powered, the shaft 14 rotates and for small differences in speeds of rotation between the heat engine and the electric motor, the freewheel operates as a conventional freewheel.

On the other hand, when the rotation speed of the heat engine and therefore of the pulley is greater than that of the track 303, the rolling elements 29 are rotated by the driver 300 and are subjected to the centrifugal force which plates the rolling elements. against the bottom 308 of the housing 302 in the manner described below.

More precisely, it can be seen in FIG. 4 that the housings 302 are aligned along a circumference of the inner face or periphery of the annular portion 301 and regularly distribute around it.

Each housing 302 has (Figure 5) at a second circumferential end 307, opposite the first end 306, a recess 309 circumferentially extending the housing 302, within which is housed the elastic member 305.

The elastic member 305 is typically constituted by a spiral or helical spring, one end of which bears against a nape closing the niche 309 on a side opposite to the housing 302, and of which an opposite end bears against the rolling member 29 via a bearing 310 sized to enter the niche 309.

Alternatively the elastic member 305 has an accordion shape.

The rolling elements 29 are typically rollers, but may also be balls.

The ramp 308 is profiled such that the depth of the housing 302 increases progressively from the first end 306 to the second end 307 into which the pad 310 opens, the depth of the housing being the dimension of this housing considered in a radial direction. This depth is less than the diameter of the roller 29 at the first end 306, and is greater than the diameter of the roller 29 at the second end 307.

In Figure 4 is shown by the arrow F the direction of rotation of the output shaft and the pulley.

When the track 303 drives the driver 300 via the rolling elements 29, which corresponds to a rotational movement of the track of the second end 307 towards the first end 306 of the housing 302, each roller 29 being in this case pushed towards the first end 306 by its associated spring 305 and coming jamming between the ramp 308 and the track 303, so that the torque can be transmitted between the track and the trainer via the rollers 29.

When the trainer rotates faster than the track, each roller 29 is biased towards the second end 307 of the housing against the return force of the spring 305 and is not wedged between the ramp 308 and the track 303, so that the driver and the track are free to rotate relative to each other, the torque not being transmitted between the pulley and the output shaft 12. A radial clearance between the rollers 29 and the track 303 appears when the torque is no longer transmitted, the free wheel being dimensioned accordingly.

The function of the free wheel is clearly shown in FIG. 3, in which it can be seen that starting a motor using the starter described above is broken down into two successive phases. During the first phase (P1 in FIG. 3), the electric motor 16 drives the heat engine, the torque being transmitted through the output shaft 12, the pulley 80 and the belt 89. Freewheel 30 transmits the torque. During the second phase (P2 in FIG. 3), the heat engine is started and drives pulley 80 through belt 89 at a high rotational speed. The pulley 80 then rotates faster than the output shaft 12 driven by the electric motor 16, and the free wheel 30 does not transmit the torque of the pulley 80 to the shaft 12 so that the electric motor 16 is formed.

Indeed, if the ratio of the belt transmission between the pulley 80 and the shaft of the engine is 2.5, and if each gear 18/19 has a ratio of 5, the engine running at idle 1000 revolutions / minute would cause the armature of the electric motor to more than 60,000 rev / min in the absence of freewheeling.

Now the armature is sized for a maximum rotational speed of 30000 revolutions / minute, and would be very quickly destroyed if it was driven at 60000 revolutions / minute.

The presence of the freewheel 30 is therefore essential to uncouple the output shaft 12 of the pulley 80 once the engine has started.

It will also be noted that during the first phase, the speed of the pulley becomes temporarily greater than that of the output shaft, during very short time intervals, after each compression phase of the cylinders of the heat engine. During these time intervals (points I of Figure 3), the free wheel does not transmit torque. The jamming and unhooking of the freewheel are thus made easy and safe.

According to a particularly advantageous aspect of the invention, the driver 300 and the track 303 are respectively rotatably connected to the pulley 80 and to the front section of the output shaft 12.

The driver 300 of Figures 2 and 7 is typically constituted by the rear portion 90 of the pulley 80, the housings 302 being hollowed out in the inner periphery of the rear portion 90 internally annular and axially oriented relative to the axis X1. Thus, in FIG. 2, the housings 302 are hollowed out in an axial-facing outer wall of the rear chamber 843.

The track 303 is constituted by a cylindrical section of the output shaft 12, engaged in the rear chamber 843 and providing a radial rolling surface to the rolling elements 29.

The rear chamber 843 of annular form (Figure 2) is closed on a rear side by a plate 95 integral with the pulley 80 and provided with a central portion perpendicular to the axis X1, the central portion now axially rolling elements 29 in the housing 302 and guiding these elements in rotation. The plate 95 is traversed at its center by the output shaft 12. It will be noted that the outer periphery of the rear portion 90 of FIG. 2 is chamfered to reduce the axial size, the plate 95 thus being able to penetrate into the opening of the front portion 481 of the housing 48 allowing the passage of the shaft 12.

Furthermore, the free wheel 30 comprises means for keeping the rolling elements 29 at a distance from the track 303 when the driver 300 is driven by the pulley 80 at high speed with respect to the track 303 in the second direction.

The rolling elements 29 are kept away from the track 303 by the centrifugal force when the driver 300 rotates at a high speed relative to the track 303 in the second direction.

More specifically, each rolling element 29 is kept in equilibrium under the combined effect of the centrifugal force and the force exerted by the elastic member. 305, separated from the track 303, in contact with a point P of the ramp 308.

For this purpose, the respective ramps 308 of the housings 302 each have a slope from the first end 306 to the second circumferential end 307 calculated so that the rolling element 29 is biased towards the second circumferential end 307 under the effect centrifugal force when the driver 300 rotates at a high speed relative to the track 303 in the second direction, as shown in FIG. 5.

The centrifugal force exerts on the rolling element 29 a radially outward effort, represented by the arrow FC of FIG. 5, applied to the center C of the element 29. This element 29 also undergoes a force resulting from the reaction of the ramp 308, represented by the arrow FR in FIG. 5, this force exerted at the point of equilibrium P in a direction perpendicular to the tangent to the ramp 308 at this point P, radially inwards.

The profile of the ramp 308 is such that the direction perpendicular to the tangent to the ramp 308 at this point of equilibrium P forms an angle with respect to the radial direction passing through the center C of the roller. The reaction force is angularly offset in the trigonometric direction with respect to said radial direction, in the representation of FIG. 5.

The sum of the centrifugal force FC and the reaction force FR is a force substantially perpendicular to the radial direction passing through the center C, oriented towards the second end 307 of the housing 302, that is to say going to the against the force of the spring 305.

The stiffness of the elastic members 305 and the profile of the ramps 308 are chosen so that the elements rollers 29 roll on the track 303 when the driver 300 rotates with respect to the track 303 at a rotation speed lower than a predetermined threshold, these elements being kept at a distance from the track 303 for a speed of rotation greater than said threshold.

The predetermined threshold is typically chosen greater than 800 revolutions per minute, and for example equal to 1000 revolutions / minute.

It is therefore clear that the starting device described above has multiple advantages.

The particular design of the free wheel 30 makes it possible to roll the rollers 29 on the track 303 when the pulley 80 rotates relative to the output shaft 12 at a moderate rotational speed, and to keep the rollers at a distance from the track 303 for a high speed of rotation.

Thus, the rollers will roll on the track 303 for example during the time intervals of the first phase P1 of the engine starting following the compression stages of the cylinders where the heat engine leads the pulley 80.

On the other hand, the rollers will be kept apart from the track 303 as soon as the heat engine reaches a sufficient speed, for example equal to the idling speed, as for example during the second phase of starting the heat engine.

Because the rollers are not in contact with the track as soon as the speed of rotation is high, the wear of these rollers is reduced, and the life of the freewheel is extended.

This type of freewheel is particularly suitable for so-called permanent engagement starting devices of the type illustrated in FIGS. 2 and 7, which have no crew 28 sliding along the output shaft 12 of the type shown in Figure 1.

In the device illustrated in Figures 2 and 7, the free wheel 30 is fixed axially, the driver 300 is continuously engaged with the pulley 80. It is thus possible to considerably simplify and lighten the structure of the starting device and remove the fork 66 , the front gear 32 and the ring gear 118, as seen in FIG. 2.

The electromagnetic contactor 62 and its mobile core 64 can in this case be replaced by a much simpler contactor, for example of the mechanical type, which only controls the starting of the electric motor 16.

The starting device of this fact can be shortened axially, since it is no longer necessary to provide a space for the axial displacement of the moving element 28.

The starting device can also be shortened axially because the free wheel 30 is integrated in the central bore of the pulley 80.

The permanent engagement starting devices of the type of Figures 2 and 7 have the advantage of being quieter, since the meshing of the pinion 32 in the ring gear 118 is removed.

According to the variant embodiment of the invention shown in FIG. 7, the pinion 52-satellite gate assembly 41 constitutes the simplified output shaft of the rear gearbox 18.

The ring 46 has a cylindrical shape of axis X1, and carries an internal toothing, the planet gears 36 and 37 of the two reducers thus meshing with the same toothing and with respectively the sun gables 52, 53.

This ring 46 bears on a radially outer face of the locking means in rotation relative to the housing 48, for example protruding parts penetrating into complementary recesses of the housing 48 or vice versa. Rotational locking means therefore intervene between the hollow front portion 481 of the casing 48 and the ring 46.

It will be appreciated, in the light of FIGS. 2 and 7, that the front portion 481 of the casing is simplified and is less bulky radially.

The ring 46 is also locked axially relative to the casing 48 by means of bosses 484 formed in the housing 48 projecting inwardly from a rear side of the ring 46.

The bosses 484 belong to a tubular cylinder head of the electric motor 16 carrying the stator 161 thereof. The cylinder head is sandwiched between the front 481 and rear 482 portions of the housing 48 being tightened by the tie rods 483.

It will be appreciated that the common ring 46 makes it possible to reduce the number of parts and the distance between the plate force-fitted on the axes of the satellites 36 of the first front gearbox 19 and the planet carrier 41 of the second rear gearbox 18, which are thus adjacent. It will be noted that the satellite gate 41, in the form of a flange of transverse orientation, may have a smaller thickness at its outer periphery so that the axes 38 may come closer to the axes 39. The starting device is thus even more compact axially.

Axes 38, 39 of axial orientation of the satellites 36, 37 are aligned and implanted on the same circumference. This results, in combination with the ring 46, a standardization of the satellites 36, 37, the axes of the satellites and plates fitted on the axes of the satellites, the splines of the gears 52, 53 being similar, axially in the axial extension of one another and of the same mean diameter.

This ring 46 is of simple shape because it is devoid of flange which reduces the axial size, especially between the satellites of the two reducers 18, 19, and remove guide bushes.

Note that the device comprises an annular dust cover 49 of radial general orientation, a radially inner edge extends flush with the grooves 51 of the armature shaft 14, and whose radially outer edge is rigidly fixed on the ring 46, this outer edge being pinched between the bosses 484 and a rear end of the ring 46.

The dust cover 49 is rigidly fixed on the ring 46, for example by means of pins carried by the ring 46, passing through corresponding openings of the dust cover 49 and heat-crushed (riveting).

The device further comprises an annular sealing washer 99 interposed axially between the ring 46 and the front bottom of the casing 48 belonging to the front portion 481 thereof, this washer 99 extending in a plane perpendicular to the axis X1 and surrounding the rear portion of pulley 80.

The washer 99 blocks the opening of the front portion 481 of the casing 48 in association with the pulley 80 and the fixed portion 221.

More precisely the washer 99 is traversed by the rear portions of the fixed portion 221 and the pulley 80. A small radial clearance exists between the washer 99 and the rear portion of the pulley 80.

Thus both reducers are well protected against pollution. In addition the 18,19 gearboxes can be greased without the fat coming pollute the belt 89, in particular thanks to the washer 99.

This washer 99 serves as an axial stop at the rear portion or end 90 of the pulley 80. This rear end has for this purpose a transverse shoulder (not referenced) to cooperate with the washer 99 thus also constituting a thrust washer.

To guide the output shaft 13 of the rear gear 18, this shaft 13, forming a planet gear 52-gate assembly 41, comprises a central bore 131 piercing axially along its entire length, the free end before 54 of the armature shaft 14 passing through this central bore 131 and being engaged by its end portion 541 in the blind axial bore 57 of the rear face of the portion 21 with radial interposition of the guide sleeve 63 between the outer periphery of the part end 541 and the radial wall of the bore 57.

Preferably a small axial clearance exists between the driver 300 and the front portion 481 of the housing 48, more precisely between the aforementioned rear extension of the housing 48 and the driver.

Other guide bushes 132 are interposed between the outer periphery of the front free end 54 and the inner radial wall of the central bore 131, the shaft 13 being thus mounted loosely on the free end 54 before the free end. using bearing means, the sockets being replaceable by needle bearings or other types of bearing.

the front portion 54 thus serves as a centering pinion 52.

It will be noted that the armature shaft 14 has an abutment section (not referenced), here cylindrical, between its front end 54 and its pinion 53. Thus there is an axial clearance between the planet carrier 41 of the pinion 52 and the grooves of the pinion 53 of the shaft 14 so that the chamfered satellites 37 mesh along their entire length with the grooves 51.

In addition, the central bore 131 of the planet gear 52-gate assembly 41 has at its rear face an increase in diameter for receiving the front portion of the abutment section, whose front face bears against the transverse shoulder. (not referenced) formed in favor of the increase in diameter of the bore 131.

Thus, the pinion 52 is wedged axially between the fixed part 21 and the abutment section.

In an alternative embodiment (FIG. 8), the ring gear 46 is radially staggered, and comprises a front cylindrical section of first diameter constituting the ring gear 44 of the front gear unit 19 and a rear cylindrical section of second diameter different from the first component of the ring gear. 45 of the rear reducer 18, the front and rear sections being mutually secured by a shoulder.

Thus, the front and rear sections each have their own internal toothing, the teeth may be different at the front and rear.

It may be the same with respect to the teeth of crowns 44 and 45 of FIG.

Of course, in FIG. 7, the ring 46 can be immobilized in rotation by means of studs engaged in grooves formed in the edge of the opening of the rear extension as described in the document FR A 2 787 833 to which reference will be made.

It will be appreciated that by virtue of the invention it is possible to use a maximum of parts of a starter of the standard type.

The solution is therefore economical and furthermore can be bulky axially because the rear part of the pulley 80 belongs to the free wheel 30 and can come closest to the satellites 36, thanks to the opening of the front portion 481 of the housing 48.

Finally, it should be noted that the device for transmitting motion between the starting device and the heat engine also comprises a second drive pulley (not shown) driven in rotation, preferably in a disengageable manner when the freewheel is in the aforementioned manner of the clutch type. conical, by the crankshaft of the engine. This second pulley is rotatably connected to the pulley 80 by the belt 89.

The freewheel 30 allows uncoupling the electric motor of the engine when the engine is launched and therefore when the crankshaft has a higher rotational speed than the second pulley.

The armature shaft 14 can be coupled in FIGS. 2 and 7 permanently to the pulley 80 via the gearboxes 18, 19.

The starter device described above has many advantages.

It is particularly compact

The advantages mentioned above are achieved by means of a device consisting of a number of parts considerably reduced compared to the prior art.

In the figures shown, the pulley is configured at its outer periphery for receiving a belt and for this purpose has at least one groove for receiving the belt 89, which in FIG. 2 is a toothed belt, the pulley 80 being fluted for this purpose.

Alternatively the pulley 80 has at its outer periphery a plurality of teeth and the belt is replaced by a chain.

The movement transmission means intervening between the crankshaft of the heat engine and the pulley 80 therefore comprise at least one chain or a belt.

Of course another pulley is associated with the crankshaft

Of course the number of gearboxes depends on the applications. For example it can be provided alternatively one or three gearboxes.

It appears from the description and from the figures that the fixed front axle 21 or the fixed part 221 have the same axis of axial symmetry X1 as the output shaft 12 and that this fixed axis or this fixed part are configured to present to the rear blind hole for rotatably mounting the reduced diameter leading end of the output shaft via a bearing means, such as a guide sleeve 72.

Claims (16)

Starting device for driving a heat engine, particularly a motor vehicle, via at least one belt (89) or a chain and at least one pulley (80), this device comprising an electric motor (16) having an armature shaft (14), an output shaft (12) to be rotated by the armature shaft (14) of the electric motor (16) via one or a plurality of speed reducers (18, 19) rotatably coupling the output shaft (12) to the armature shaft (14), and an axially fixed freewheel (30) selectively selectively rotating the pulley (80) and the output shaft (12), wherein the freewheel (30) is housed in an internal bore (84) of the pulley (80) and comprises two coaxial portions (300, 303) of common axis (X1), a first coaxial parts belonging to a driver (300) integral with the rear portion (90) of the pulley (80), characterized in that the second coaxial portion (303) is integral with a trunk front of the output shaft (12) constituting the output shaft of an epicyclic gear speed reducer (19). Device according to claim 1, characterized in that it comprises two planetary speed geared front and rear gear units (19, 18) connected in series, in that the output shaft (12) constitutes the output shaft of movement of a forward planetary speed reducer (19), while the armature shaft is configured at the front to form the sun gear (53) of a rear epicyclic gearbox (18) . Device according to claim 2, characterized in that each speed reducer (18, 19) comprises a ring gear with internal teeth, in that there is provided a single ring gear (46) common to both gearboxes (18, 19) and in that the single ring gear (46) has means for locking in rotation relative to a casing (48) that the device has. Device according to any one of claims 1 to 3, characterized in that the driver (300) of the free wheel (30) is provided with an annular portion (301) coaxial with the output shaft (12), in that recesses (302) are circumferentially recessed in an inner face of the annular part (301), in that a cylindrical track (303) belonging to the second coaxial part integral with the output shaft (12) , is arranged inside the annular part (301), in that rolling elements (29) are arranged in the housings (302), and in that resilient members (305) urge the rolling elements (29). to respective first circumferential ends (306) of the housings (302). Device according to claim 4, characterized in that the bottom of each housing (302) forms a profile ramp (308) such that the rolling elements (29) are locked between the ramp (308) and the track (303) of the side of the first end (306) when the freewheel (30) transmits torque from the output shaft (12) to the pulley (80), and when the trainer (300) rotates faster than the track (303), the driver (300) and the track (303) are free to rotate relative to each other and the freewheel (30) does not transmit torque and in that the driver (300) ) and the track (303) are respectively rotatably connected to the pulley (80) and the output shaft (12). Device according to claim 4 or 5, characterized in that the free wheel (30) comprises means for holding the rolling elements (29) to distance from the track (303) when the driver (300) rotates at a high speed relative to the track (303) in the second direction. Device according to claim 6, characterized in that the rolling elements (29) are kept away from the track (303) by the centrifugal force when the driver (300) rotates at a high speed relative to the track (303). Device according to claim 7, characterized in that the rolling element (29) is kept in equilibrium at a point (P) of the ramp (308) under the combined effect of the centrifugal force and the force exerted by the elastic member (305) when the driver (300) rotates at a high speed relative to the track (303). Device according to claim 8, characterized in that the direction perpendicular to the tangent to the ramp (308) at said equilibrium point (P) forms an angle with respect to the radial direction passing through the center (C) of the element wheel (29) such that the latter is biased towards the second circumferential end under the effect of the centrifugal force when the driver (300) rotates at a high speed relative to the track (303) in the second direction. Device according to claim 9, characterized in that the stiffness of the elastic members (305) and the profiles of the ramps (308) are chosen so that the rolling elements (29) roll on the track (303) when the driver (300) rotates relative to the track (303) at a speed below a predetermined threshold, these elements being kept at a distance from the track (303) for a speed of rotation greater than said threshold. Device according to Claim 10, characterized in that the predetermined threshold is greater than 800 revolutions per minute. Device according to any one of claims 4 to 11, characterized in that the rolling elements (29) are rollers and in that the elastic members (305) are housed in recesses (309) circumferentially extending the housings (302). at a second circumferential ends thereof. Device according to any one of claims 4 to 12, characterized in that the annular portion (301) of the driver (300) and the cylindrical track (303) are in one piece respectively with the pulley (80) and with the output shaft (12). Device according to any one of the preceding claims, characterized in that it comprises an inner partition (841) perpendicular to the axis (X1) of the pulley (80) dividing the internal bore (84) of the pulley into a cylindrical front chamber (842) and a cylindrical rear chamber (843) and that the freewheel (30) is housed in the rear chamber (843). Device according to claim 14, taken in combination with claim 13, characterized in that the cylindrical track (303) belongs to a cylindrical section before the output shaft (12), while the housing (302) of the part annular (301 of the driver (300) are hollowed out at the inner periphery of the rear portion (90), internally annular, of the pulley (80). Device according to Claim 14 or 15, characterized in that the front chamber (842) receives a fixed front axle (21) or an axially fixed cylindrical part (221), in that bearing means (82) intervene between the periphery external of the front axle (21) or the fixed part (221) and the inner periphery of the pulley (80) and in that the front axle (21) or the fixed part (221) are integral with the front part of a housing ( 48) that the device presents.

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