EP2865882A1 - Starter drive assembly with improved friction clutch and corresponding starter for the heat engine of a motor vehicle - Google Patents

Abstract

The invention relates primarily to a starter starter for a motor vehicle engine comprising a pinion carrier (83) on which a drive pinion (32) is mounted, a driver (81) mounted on a drive shaft ( 33), characterized in that it further comprises a clutch (82) friction interposed between the driver (81) and the drive pinion (32) comprising a reaction element (91) integral in rotation with the pinion gear. drive (32) and a pressure member (92) rotatably connected to the driver (81), a set of internal (931, 932) and external (941-943) disks alternately rotatably connected with the driver ( 81) and the pinion carrier (83), and at least one resilient means (96, 97) arranged to provide stepped transmission of the torque by the clutch (82) when said clutch (82) passes from the unlocked state in the locked state, so that the torque level transmitted by the clutch ( 82) has at least one intermediate torque passage threshold for which only a portion of the faces facing the inner (931, 932) and outer (941-943) disks are in contact with one another and a final torque passing threshold greater than the intermediate threshold of torque passage for which all the faces vis-à-vis the internal disks (931, 932) and external (941-943) are in contact with each other.

Description

TECHNICAL FIELD OF THE INVENTION

An improved friction clutch launcher and the corresponding motor vehicle engine starter are disclosed.

The invention finds a particularly advantageous application for vehicles equipped with the stop and restart function of the engine (function called "stop and start" in English) depending on traffic conditions.

BACKGROUND TECHNOLOGY

In order to start the engine of a vehicle, it is known to use a starter capable of transmitting mechanical energy to turn a crankshaft of the engine via gear wheels. For this purpose, the starter comprises a pinion installed on a drive shaft driven in rotation by a rotor of an electric motor. This pinion is provided with teeth capable of meshing with the teeth of a toothed wheel coupled to the crankshaft of the engine called starter ring.

In a starter starter, the drive gear belongs to a launcher mounted movably in translation on a drive shaft to move from a rest position in which the drive pinion is disengaged from the starter ring to a position active in which the drive pinion engages with the starter ring, and vice versa.

A starter launcher 1 set shown on the figure 1 comprises for this purpose the drive pinion 2 slidably mounted on a pinion carrier 4, a driver 3 mounted on a drive shaft via a helical link, and a friction clutch 5 interposed between the pinion 2 and the driver 3 .

More specifically, the pinion carrier 4 comprises a sleeve 7 on which is mounted the drive pinion 2 movable in translation, a plate 8 extending radially from a rear end of the sleeve, and an annular skirt 12 orientation axial connected to the outer periphery of the reaction plate 8.

The pinion 2 further comprises a cavity 13 for housing an elastic member 16, here a coil spring. This spring 16 is supported at one of its axial ends on the bottom of this cavity 13 constituted by an annular wall of radial orientation connected to the inner periphery of the pinion 2. The other axial end of the spring 16 is supported on the transverse front face of the reaction plate 8. In addition, a circlip 17 forming an axial stop is mounted in a groove machined in the front end of the sleeve 7.

When the pinion 2 is in abutment on the starter ring and does not penetrate into it (state tooth against tooth), the spring 16 is compressed and the pinion 2 back along the sleeve 7 towards the reaction plate 8 in a position away from the stop 17. The pinion carrier 4 can nevertheless continue to advance, which will allow the cam of the control lever to continue to move to ensure the subsequent closure of the clutch 5.

The friction clutch 5 further comprises a pressure element 6 constituted by a shoulder of the driver 3, a reaction element constituted by the plate 8 of the pinion carrier, as well as friction discs 9, 9 'located between the pressure element 6 and the reaction plate 8. The external disks 9 and the internal disks 9 'are alternately rotatably connected respectively to the pinion carrier 4 and to the driver 3.

The clutch 5 is able to move from an unlocked state in which the driver 3 and the pinion 2 are uncoupled in rotation with one another in a locked state in which the pinion 2 and the driver 3 are coupled. in rotation with each other. For this purpose, the driver 3 is movable in translation relative to the reaction plate 8, in the limit of an axial play, between a disengaged position corresponding to the unlocked state of the clutch 5 and a coupled position corresponding to the locked condition of the clutch 5. The discs 9 are housed in a housing 11 delimited by the reaction plate 8, the annular skirt 12 of axial orientation extending from the outer periphery of the reaction plate 8, as well as by a closure ring 14 traversed centrally. by the driver 3. Furthermore, the ring 14 is annularly hollowed at its outer periphery for mounting an assembly cap 15.

An axially acting spring washer 18 is mounted in an annular groove 19 formed by a reduction in thickness that the plate 8 has at its inner periphery. This washer 18 is supported on the reaction plate 8 and on one end of the driver 3 for action on the driver 3 and push it backwards, that is to say in a direction opposite to the plateau 8. This washer 18 thus ensures a clearance between the disks 9 of the clutch in the rest position.

The trainer 3 further comprises a groove 21 delimited by two transverse walls 22, 23 within which the lower part of a control lever of the starter is intended to be mounted. A wall 22 called pusher corresponds to the wall against which the lever is supported to push the driver 3 towards the starter ring. The other wall 23 called shooter is a wall against which the lever is supported to move the driver 3 from the starter ring.

The operation of such a starter during a transition from the rest position to the active position is described below.

In the rest position of the launcher 1, the spring 16 urges the pinion 2 towards the axial stop 17, which corresponds to an initial position of the drive pinion 2. Starting from the rest position, the control lever of the A starter which has a cam shape initially acts on the ring 14 of the casing 11 which then moves the pinion carrier 4 axially in the direction of the starter ring along the drive shaft.

During this step, the driver 3 is in the uncoupled position so that the pinion 2 is free to rotate relative to the driver in both sense of rotation. The axial movement continues, the pinion 2 arrives in the vicinity of the starter ring.

In a second step, the free pinion 2 rotates slightly into the crown. The lever in contact with the pusher 22 axially moves the driver 3 and the shoulder 6 thereof towards the reaction plate 8. The spring washer 18 is then compressed and the clearance between the discs is canceled. As is apparent from the figure 2 when the clutch 5 moves from the unlocked state to the locked state, the transmitted torque changes to a high threshold S1 over a very short duration T (of the order of 8ms), which generates mechanical shocks on the line of the drive shaft. These mechanical shocks are mitigated by shock absorption systems installed at a coupling device between the drive shaft and the electric motor shaft of the starter. However, for starters that undergo a very high number of operating cycles, such as those fitted to vehicles equipped with the "stop and start" function, the shocks generated during the closing of the clutch can quickly damage the engine. starter after wear of the shock absorption systems.

OBJECT OF THE INVENTION

• un porte-pignon sur lequel est monté un pignon d'entraînement pour engrènement avec une couronne dentée de démarrage d'un moteur thermique,
• un entraîneur monté sur un arbre d'entraînement,

caractérisé en ce qu'il comporte en outre un embrayage à friction intercalé entre l'entraîneur et le pignon d'entraînement comprenant un élément de réaction solidaire en rotation du pignon d'entraînement et un élément de pression solidaire en rotation de l'entraîneur, un ensemble de disques internes et externes alternativement liés en rotation avec l'entraîneur et le porte-pignon, ledit élément de pression étant mobile axialement par rapport à l'élément de réaction pour faire faire passer ledit embrayage d'un état déverrouillé dans lequel l'entraîneur et le porte-pignon sont désaccouplés en rotation l'un avec l'autre à un état verrouillé dans lequel l'entraîneur et le porte-pignon sont accouplés en rotation l'un avec l'autre, et - au moins un moyen élastique agencé entre l'élément de pression et l'élément de réaction, le moyen élastique étant agencé pour permettre une transmission étagée du couple par l'embrayage lorsque ledit embrayage passe de l'état déverrouillé à l'état verrouillé.The invention aims to effectively remedy this disadvantage by proposing a starter starter for a motor vehicle engine comprising:

• a pinion carrier on which is mounted a drive pinion for meshing with a ring gear for starting a heat engine,
• a trainer mounted on a drive shaft,

characterized in that it further comprises a friction clutch interposed between the driver and the drive pinion comprising a reaction member integral with the drive pinion and a pressure member integral with the driver, a set of internal and external disks alternately rotatably connected with the driver and the pinion carrier, said pressure element being axially movable with respect to the reaction element for causing said clutch to move from one state to another; unlocked in which the driver and the pinion carrier are uncoupled in rotation with each other in a locked state in which the driver and the pinion carrier are coupled in rotation with each other, and - at least one elastic means arranged between the pressure element and the reaction element, the elastic means being arranged to allow a staged transmission of the torque by the clutch when said clutch passes from the unlocked state to the locked state.

Thus, by providing a stepped passage of the torque when the clutch closes with at least one intermediate stage of torque passage, the duration over which the torque between the electric motor and the starter gear is transmitted is increased. limits the torque peaks on the line of the drive shaft. In addition, the invention makes it possible to pass through an intermediate locking state in which only a portion of the disks of the clutch ensure the passage of the torque. The invention thus makes it possible to increase the life of the starter by reducing the intensity of the forces to which the shock absorption systems are subjected.

The elastic means is arranged so that when the clutch is between the unlocked and locked state, the resilient means allows only part of the internal and external disks to allow torque to be passed to an intermediate torque threshold while being in position. contact with each other and that in the locked position the elastic means allows all the internal and external disks to be in contact to allow a torque to be passed up to a final threshold of passage of torque greater than the intermediate threshold of passage of couple.

The clutch then acts as a torque limiter by allowing the discs in contact to rub against each other, which will absorb some of the torque peaks.

According to one embodiment, the elastic means is able to pass from a decompressed state in which the elastic means prevents contact between at least one face of an internal disk and at least one face of a corresponding external disk to a state a tablet in which the face of the inner disk and the face of the corresponding outer disk are in contact with each other to increase the level of torque passed through the clutch. By bringing into contact is meant pressurizing allowing the friction to provide a torque.

This embodiment makes it possible to use part of the disks to pass a torque then all the disks to pass a torque up to a maximum threshold.

According to one embodiment, to simplify as much as possible the embodiment of the device, the launcher comprises a single elastic means positioned between two internal disks or two successive external disks.

Thus, in a first phase, a set of discs come into contact when the clutch goes from an unlocked state to a locked state and then into a second phase when the elastic means is sufficiently compressed, the discs between which the elastic means are mounted. compressed thereby to stagger the torque between the pinion and the launcher coach.

According to another embodiment, the elastic means has the technical characteristic of being at two slopes, that is to say that it comprises during its compression a first period in which it comprises a first stiffness and then in a second compression period a second stiffness. In this embodiment, the advantage over the previous embodiment is to have a non-constant line during the first phase of the unlocked state in the locked state

According to each embodiment, the elastic means is an elastic device, for example a spring.

According to one embodiment, the launcher comprises two elastic means having different stiffnesses each positioned between two internal disks or two successive external disks, so that when the clutch passes from an unlocked state to a locked state, in a first step, the elastic means of lower stiffness is compressed while the elastic means of upper stiffness is decompressed so as to obtain the intermediate threshold of passage of torque, and in a second step, the elastic means of lower and upper stiffness are compressed simultaneously so as to obtain the final threshold of torque transition. Compared with the use of a single elastic means, this configuration makes it possible to substantially increase the duration of passage of the torque by the clutch and thus to reduce shocks because of the time required to ensure the successive compression of the different elastic means. .

According to one embodiment, the pressure element comprises a friction surface 7 capable of passing a torque when it is in contact with the clutch disk integral in rotation with the pinion body.

According to an example of this embodiment, the launcher comprises an elastic means positioned between the pressure element and one of the disks linked in rotation with the pinion carrier.

This embodiment has the advantage that the elastic means is housed without difficulty. In addition, all the disks are brought into contact at a first time under a pressure related to the elastic means for the passage of a torque to an intermediate threshold and then in a second time all the disks are brought into contact under a greater pressure to transmit a torque up to a threshold higher than the intermediate threshold.

According to one embodiment, the launcher comprises an elastic means positioned between the reaction element and one of the disks linked in rotation with the driver.

According to an example of this embodiment, the reaction element comprises a friction surface capable of passing a torque when it is in contact with the rotating disc of the drive.

This embodiment has the advantage that the elastic means is housed without difficulty. In addition, all the disks are brought into contact at a first time under a pressure related to the elastic means for the passage of a torque to an intermediate threshold and then in a second time all the disks are brought into contact under a greater pressure to transmit a torque up to a threshold higher than the intermediate threshold.

According to one embodiment, the elastic means or means are each constituted by a spring washer.

In one embodiment, the launcher has three external disks and two internal disks.

According to one embodiment, the internal disks have at their inner periphery a plurality of tabs inserted into corresponding notches located in the outer periphery of the trainer. The internal disks are thus linked in rotation with the trainer while being movable in translation relative to the latter in the limit of the clearance between the disks of the clutch.

According to one embodiment, the outer disks comprise at their outer periphery a plurality of tabs inserted inside corresponding notches located in an inner periphery of an annular skirt of the pinion carrier. The outer disks are thus connected in rotation with the pinion carrier while being movable in translation relative to the latter in the limit of the clearance between the disks of the clutch.

In one embodiment, the pressure element is constituted by a shoulder of the trainer.

In one embodiment, the reaction element is constituted by a plate of the pinion carrier.

According to one embodiment, the launcher comprises an intermediate element for reducing friction intended to be mounted between the driver and a portion of a control lever. This reduces the wear of the control lever during operation of the starter.

According to one embodiment, the launcher comprises a frustoconical spring mounted in support on the one hand against a face of a transverse plate of the pinion carrier and on the other hand against a face of the drive pinion. Such a configuration makes it possible to increase the service life of the spring with respect to the use of a coil spring.

The invention also relates to a motor vehicle engine starter equipped with a launcher according to the invention.

BRIEF DESCRIPTION OF THE FIGURES

• La figure 1, déjà décrite, montre une vue en coupe longitudinale du lanceur du démarreur de moteur thermique illustrant l'arrière-plan technologique de l'invention;
• La figure 2, déjà décrite, est une représentation graphique du niveau de couple passé par l'embrayage en fonction du temps pour le lanceur de la figure 1 ;
• La figure 3 montre une vue en coupe longitudinale d'un démarreur de moteur thermique de véhicule automobile selon l'invention;
• La figure 4 montre une vue en coupe longitudinale du lanceur du démarreur de la figure 3;
• La figure 5 est une représentation graphique du niveau de couple passé par l'embrayage en fonction du temps pour le lanceur de la figure 4;
• Les figures 6a et 6b sont des représentations en perspective du porte-pignon du lanceur de la figure 4 suivant différents angles de vue;
• Les figures 7a et 7b montrent respectivement des vues en perspective et de côté d'une rondelle ressort utilisée avec le lanceur de la figure 4;
• Les figures 8a et 8b montrent des vues en perspective du levier de commande et de l'entraîneur respectivement lorsque l'embrayage est dans un état verrouillé et dans un état déverrouillé;
• Les figures 9a et 9b montrent des vues de côté de l'ensemble des figures 8a et 8b respectivement lorsque l'embrayage est dans un état verrouillé et dans un état déverrouillé.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given for illustrative but not limiting of the invention.

• The figure 1 , already described, shows a longitudinal sectional view of the starter of the engine starter illustrating the technological background of the invention;
• The figure 2 , already described, is a graphical representation of the level of torque passed by the clutch as a function of time for the launcher of the figure 1 ;
• The figure 3 shows a longitudinal sectional view of a motor vehicle engine starter according to the invention;
• The figure 4 shows a longitudinal sectional view of the launcher of the starter of the figure 3 ;
• The figure 5 is a graphical representation of the torque level passed by the clutch as a function of time for the launcher of the figure 4 ;
• The Figures 6a and 6b are perspective representations of the sprocket carrier of the launcher of the figure 4 according to different angles of view;
• The Figures 7a and 7b show respectively perspective and side views of a spring washer used with the launcher of the figure 4 ;
• The Figures 8a and 8b show perspective views of the control lever and the driver respectively when the clutch is in a locked state and in an unlocked state;
• The Figures 9a and 9b show side views of all of Figures 8a and 8b respectively when the clutch is in a locked state and in an unlocked state.

Identical, similar or similar elements of Figures 3 to 9b keep the same reference from one figure to another.

DESCRIPTION OF EXAMPLES OF EMBODIMENT OF THE INVENTION

In the remainder of the description, a forward-to-back orientation corresponds to a left-to-right orientation on the Figures 3, 4 , 8a, 8b, 9a, 9b . Thus, a front face of a member is the face facing the front bearing 50 and the rear face is the face facing the rear bearing 53.

With reference to the figure 3 , the starter 30 according to the invention comprises a friction launcher 31 described in more detail hereinafter provided with a drive pinion 32 mounted to be movable in translation on a drive shaft 33. The launcher 31 can pass from a rest position (that of the figure 3 ) in which the drive pinion 32 is disengaged from a starting ring of a heat engine at an active position (not shown) in which the drive pinion 32 engages a starting ring gear, and vice versa.

For this purpose, the starter 30 comprises an electric motor 37 composed of a stator 38 and a rotor 39 mounted coaxially. The stator 38 surrounds the rotor 39, which is mounted on a shaft 42 of axis X said rotor shaft inside a yoke 43. The latter is secured to a support 45 of the starter to be fixed on a fixed part of the motor vehicle. The stator 38 comprises for example an inductor winding having two pairs of windings, which are each wound around a pole mass integral with the yoke. The axis of each winding is radial with respect to the X axis of the rotor. Alternatively or in addition, the stator 38 comprises a plurality of permanent magnets.

The rotor 39 mounted on the rotor shaft 42 comprises a bundle of plates provided with grooves for mounting electrical conductors in the form of pins. These conductors are interconnected to form a rotor winding in connection with conductive blades belonging to a collector 48 integral with the rotor shaft 42 cooperating with brushes 49a, 49b described below. The X axis of the rotor shaft 42 coincides with the axis of the drive shaft 33.

The drive shaft 33 has its front end rotatably mounted in the front bearing 50, via a bearing 51. The rotor shaft 42 has its rear end mounted in a bearing 52 of the rear bearing 53 and which is secured to a brush holder 54.

The starter 30 further comprises a reduction system 58 mounted between the rotor shaft 42 and the drive shaft 33, one end of which is connected to the rotor shaft 42 and the other end is connected to the shaft 33. The reducing system 58 is in this case an epicyclic gear comprising a cylindrical ring gear 59 internally connected to the housing. The teeth of the ring gear 59 mesh with planet wheels mounted to rotate about axes carried by a transverse plate 60 integral with the rear end of the drive shaft 33. The sun gear 61 is connected to the front end of the rotor shaft 42.

The ring gear 59 of the reduction system 58 is preferably equipped with damping pads 62 making it possible to absorb observable overthrows during starting of the heat engine. A conventional assembly consists of a ring 59 of plastic material on the transverse wall of which are overmolded pads 62 of elastomeric material. These pads 62 are able to compress by relative angular displacement of said pads 62 integral in rotation with the ring gear 59 with respect to compressor elements integral with the starter housing which are fixed.

Alternatively, the reducing system 58 may be any other type of reducer. For example, the reduction system 58 could comprise two gears, one of which is secured to the rotor shaft 42 and the other of the drive shaft 33. In this example, the two axes of the rotor shaft 42 and the drive shaft 33 are offset parallel to one another. In another example, the reduction system 58 may be geared left or gear concurrent.

The starter 30 further comprises a system for moving the launcher 31 from its rest position to its active position and vice versa. This displacement system comprises an electromagnetic contactor 64 extending parallel to the electric motor 37 being implanted radially above it and a control lever 65 in the form of a fork.

The brush group 49a and 49b is provided for the power supply of the rotor winding 39. At least one of the brushes 49b is electrically connected to the ground of the starter, for example the support 45, and at least one other of the brushes 49a is electrically connected to an electrical terminal 66a of the contactor, for example via a wire. The brushes 49a and 49b rub against the blades of the collector 48 when the rotor 39 is rotating. The starter 30 may comprise a plurality of brushes.

The contactor 64 comprises, in addition to the terminal 66a connected to the brush, a terminal 66b intended to be connected via an electrical connection element to a positive power supply V + of the vehicle, in particular a battery, not shown. A normally open contact (not shown), located between a terminal V + of the power supply and the terminal 66b controls the power supply of the contactor 64 to start the electric motor.

The contactor 64 comprises a movable contact plate 69 for electrically connecting the terminals 66a and 66b in order to supply the electric motor 37. The contactor 64 is also able to actuate the control lever 65 to move the launcher 31 along the X axis of the drive shaft 33 from the rest position to the active position and vice versa. The switch 64 also comprises a movable core 71, a fixed core 72, a fixed coil 73, a control rod 74 and a movable rod 75.

The control rod 74 passes through the fixed core 72 which serves as a guide. This control rod 74 has its front end bearing on the fixed core 72 and its rear end attached to the contact plate 69. The control rod 74 is subjected to the action of a compressed contact spring (not referenced) between a shoulder of the control rod 74 and the contact plate 69 to ensure the electrical contact of the contact plate 69 with the terminals 66a and 66b when the movable core 71 is in a so-called magnetized position. The movable rod 75 is fixed at its front end to the control lever 65. When the coil 73 is powered, the movable core 71 is attracted to the fixed core 72 to be in contact with the latter in a so-called magnetized position. Its movement simultaneously drives the movable rod 75, the contact plate 69 and the control rod 74 towards the rear. The movable rod 75 is further subjected to a tooth spring against tooth 78 housed inside the movable core 71 and surrounding the movable rod 75. This tooth against tooth spring 78 is supported on a rear shoulder of the movable rod 75 and a front shoulder of the movable core 71. This spring tooth against tooth 78 is compressed when the contact plate 69 moves towards the terminals 66a and 66b and that the control lever 65 can no longer advance the pinion 32. The lever 65 can not advance when the pinion 32 is locked in translation along the axis X in direction of the ring 35 by one or more teeth of the crown 35. This blocked state is called "tooth against tooth position". The compression of the tooth against tooth spring 78 absorbs shocks while applying a force on the control lever 65 transmitted to the pinion 32 to the active position. The contactor 64 further comprises a return spring 80, bearing on the fixed coil 73 and the movable core 71 to urge it forward to its rest position and simultaneously move the control lever 65 until that the pinion 32 is in the rest position.

As is clearly visible on the figure 4 , the friction launcher 31 comprises the drive gear 32 slidably mounted on a pinion carrier 83, a driver 81 actuated by the control lever 65, and a friction clutch 82 interposed axially between the driver 81 and the pinion 32 The axes of the pinion carrier 83 and of the driver 81 coincide in an axis X 'corresponding to the axis of the launcher 31. When the launcher is mounted on the starter, the axis X' of the pinion carrier 83 is coincident with the X axis of the rotor shaft 42 and the drive shaft 33. The driver 81 is internally provided with helical splines 84 in complementary engagement with external helical gears 85 carried by the shaft 33 (cf. figure 3 ). The launcher 31 is thus driven by a helical movement when it is moved by the lever 65 against the stop 88 to come, via the pinion 32, in engagement with the ring gear 35 in the active position.

More specifically, the pinion carrier 83 comprises a sleeve 100 of axial orientation having a bore 101 for its mounting on the drive shaft 33. The sleeve 100 thus serves to axially guide the pinion 32 on a smooth section of the drive shaft 33.

To allow axial movement of the pinion relative to the sleeve 100, splines 139 formed in the outer periphery of the sleeve 100 (cf. Figures 6a and 6b ) cooperate with complementary grooves formed in the inner periphery of the pinion 32. The grooves are here of axial orientation. This assembly creates a connection in rotation between the pinion 32 and the sleeve 100. At least one pad 102 is preferably interposed between the smooth portion of the drive shaft 33 and the sleeve 100. In this case, two pads 102.

The pinion carrier 83 also comprises a plate 91 of transverse orientation located in the extension of a rear end of the sleeve 100. This plate 91 is itself extended at its outer periphery by an annular skirt 105 of axial orientation. This skirt 105 is directed rearward towards the driver 81. In this case, the sleeve 100, the plate 91 and the skirt 105 are made in one piece.

The friction clutch 82 comprises a reaction element constituted by the plate 91 of the pinion carrier 83, a pressure element 92 constituted by a shoulder of the driver 81, as well as friction disks 931, 932, 941-943 located between the pressure element 92 and the reaction plate 91. The pressure element 92 is movable in translation with respect to the reaction plate 91 in the limit of an axial clearance so as to cause the clutch to pass through. an unlocked state in which the driver 81 and the pinion carrier 83 are uncoupled in rotation relative to each other due to an absence of clamping force between the pressure element 92 and the element 91, in a locked state in which the pinion carrier 83 and the driver 81 are rotatably coupled to each other by pressurizing the disks against each other by applying a clamping force between the pressure element 92 and the driver 8 1, and vice versa.

The disks 931, 932, 941-943 are housed in a housing 108 delimited by the reaction plate 91 connected to the pinion, the annular skirt 105 of axial orientation connected to the outer periphery of the reaction plate, as well as by a ring of In addition, the ring 106 is annularly hollowed at its outer periphery for mounting an assembly cap 151 of the ring to the pinion carrier 83. It is noted that the shoulder 92 penetrates part inside the ring 106. Its outer diameter is smaller than the inner diameter of the ring 106, which reduces the axial size of the launcher 31.

The disks 931, 932 and 941-943 are alternately linked in rotation with the drive pinion 32 and with the driver 81. For this purpose, first disks 931-932, called internal disks, have at their inner periphery a plurality tabs inserted inside corresponding notches 109 located in the outer periphery of the driver 81. These notches 109 are for example grooves whose depth extends radially in an outer wall of the driver 81 and whose length extends along the axis X '. Second disks 941-943, so-called external disks, comprise at their outer periphery a plurality of tabs inserted inside corresponding notches 110 located in the inner periphery of the annular skirt 105. These notches 110 are clearly visible to the Figures 6a and 6b are for example grooves whose depth extends radially in the annular skirt 105 and whose length extends along the axis X '. The internal disks 931, 932 are thus rotatably connected with the driver 81 and the external disks 941-943 are connected in rotation with the drive pinion 32 via the annular skirt 105. The disks 931, 932, 941-943 can slide along the axis X 'through the notches 109, 110 and their corresponding tabs.

The discs 931-932, 941-943, for example made of a friction material, such as bronze and steel, make it possible to transmit a frictional torque between the driver 81 and the pinion 32. In this case, the number of internal disks 931-932 is two and the number of external disks 941-943 is three.

However, the number of disks of the clutch 82 is likely to vary according to the intended application and the torque to be transmitted. It will be possible to increase the number of discs to transmit more torque without having to increase the diameter of the coach.

In addition, the launcher 31 comprises two elastic means 96, 97 having different stiffnesses each positioned between two external disks 941-943. The elastic means 96 located on the side of the pressure element 92, said elastic means of lower stiffness, has a stiffness lower than the elastic means 97 located on the side of the reaction plate 91, said elastic means of upper stiffness. In this case, the elastic means 96 of lower stiffness is located between the outer disks 942 and 943. The elastic means 97 of upper stiffness is located between the outer disks 941 and 942. Alternatively, it would be possible to invert the positioning two elastic means 96, 97.

Each elastic means 96, 97 is capable of passing from a decompressed state in which the elastic means 96, 97 prevents contact between the faces of an inner disk 931, 932 and the faces facing the disks. 941-943, in a compressed state in which the faces of the inner disk 931, 932 and the opposite faces of the corresponding outer disks 941-943 are in contact with each other to allow the clutch 82 to ensure a torque transition by friction.

Each elastic means 96, 97 is preferably constituted by an annular spring washer located at the outer periphery of an inner disk. These spring washers 96, 97 are similar to the spring washer 115 used with the retaining washer 118 and shown in FIGS. Figures 7a and 7b . The spring washers 96, 97 each have an inner diameter D1 corresponding to an outer diameter of an inner disk 931 or 932, an outer diameter D2 corresponding to an inner diameter of the pinion carrier 83. The spring washers 96, 97 also have a Thickness in the decompressed state that is greater than the thickness of an internal disk 931 or 932.

When the clutch 82 moves from the unlocked state to the locked state by displacement of the pressure element 92 towards the reaction plate 91, it is observed, during the compression of the elastic means 96 of lower stiffness between the moments t1 and t2, a linear increase in the torque level transmitted by the clutch 82 (cf. figure 5 ). This linear increase in the level of torque corresponds to a progressive contact between the faces of the internal disk 932 with the faces of the external disks 942, 943 facing the internal disk 932. This linear increase in the level of torque continues until a intermediate threshold of passage of torque S1.

This intermediate torque passing threshold S1 is observable between times t2 and t3 when the elastic means 96 of lower stiffness is compressed so that the faces of the outer disks 942, 943 are pressurized against the corresponding faces of the inner disk 932, while the resilient means 97 of upper stiffness is further decompressed preventing contact of the faces of the outer disks 941, 942 with the faces vis-à-vis the inner disk 931.

Then, during the compression of the elastic means 97 of greater stiffness between the instants t3 and t4, a new linear increase in the torque transmitted by the clutch 82 is observed. This linear increase in torque corresponds to a progressive contact between the faces of the internal disk 931 with the faces of the corresponding external disks 941, 942. This new linear increase of the torque continues until a final threshold of passage of torque S2.

This final torque passing threshold S2 is observable between instants t4 and t5 when the elastic means 96 of lower stiffness is compressed so that the faces of the external disks 942, 943 are pressurized against the corresponding faces of the internal disk 932, and that the elastic means 97 of upper stiffness is also compressed so that the faces of the outer disks 941, 942 are pressurized against the corresponding faces of the inner disk 931.

Thus, by providing a stepped passage of the torque, the invention makes it possible to increase the duration T on which the torque is transmitted by the clutch 82 to the starter ring, which limits the torque peaks on the line of the drive shaft. Indeed, thanks to the use of elastic means 96, 97, the torque can be passed over a period more than twice as long as for a clutch 82 without elastic means 96, 97 (T is of the order of 20ms for the launcher of the figure 4 while T was about 8ms for the launcher of the figure 1 ).

In addition, the invention makes it possible to pass through an intermediate locking state in which only a portion of the disks of the clutch 82 ensure the passage of the torque. The clutch 82 then acts as a torque limiter by allowing the discs in contact to rub together. against the others, which will allow to absorb some of the peak torque when starting the engine. The invention thus makes it possible to increase the life of the starter by reducing the intensity of the forces to which the pads 62 shock absorbers are subjected.

Alternatively, a single elastic means 96 or 97 is positioned between two internal disks 931, 932 or two successive external disks 941-943. However, in this case, the final threshold of torque passage S2 will be reached more quickly than in the case of the use of two elastic means 96 and 97. Indeed, in this case, the discs located in the clutch zone where no resilient means is present will tend to rub against each other rapidly after clutch 82 closes.

As a variant, the elastic means or means 96, 97 could be positioned between two successive internal disks. In the case where two elastic means 96 and 97 are used, the clutch 82 will then comprise at least three internal disks.

Of course, the number of intermediate thresholds of torque transition S1 may be increased by increasing the number of clutch disks 82 used and the number of elastic means 96, 97 having different stiffnesses.

Alternatively or in a complementary manner, an elastic means 96, 97 is positioned between the pressure element 92 and one of the external disks 941-943 linked in rotation with the pinion carrier 83. An elastic means 96, 97 may also be positioned between the reaction element 91 and one of the internal disks 931, 932 rotatably connected with the driver 81. The pressure element 92 or the reaction element 91 could also participate in the torque transmission of the clutch 82 in having a contact surface adapted to friction with one of the disks 931, 932, 941-943.

The launcher 31 also comprises an elastic means 115 exerting a force separating the driver 81 from the reaction plate 91 towards the uncoupled position. For this purpose, the elastic means 115 is mounted in compression between a radial face of the reaction plate 91 and an end of the driver 81.

More specifically, the elastic means 115 is positioned inside a groove 117 which is clearly visible on the figure 6a closed by a washer 118, said holding washer, connected in rotation with the reaction plate 91. The groove 117 is formed by a circular groove about the axis X '. The groove 117 thus corresponds to a reduction in thickness at the inner periphery of the reaction plate 91. The groove 117 is open axially on the rear side and radially closed by two annular walls of axial orientation.

In addition, the groove 117 comprises at its outer periphery a set of notches 124 spaced angularly in a regular manner intended to receive lugs 130 of corresponding shape located at the outer periphery of the retaining washer 118.

The holding washer 118 closes the open axial end of the groove 117 inside which the elastic means 115 is positioned. Thus, the holding washer 118 is connected in rotation with the reaction plate 91 and is movable in translation. relative to this plate 91 insofar as the lugs 130 of the retaining washer 118 can slide inside the corresponding notches 124 formed in the reaction plate 91.

The elastic means 115 is in this case a spring washer positioned inside the groove 117. In an exemplary embodiment, this washer 115 has a cylindrical helical shape, as is clearly apparent from the Figures 7a and 7b . This washer is provided with corrugated turns. The spring washer 115 is mounted compressed between the bottom 119 of the groove 117 and the retaining washer 118 resting on the end of the driver 81 to separate the driver 81 from the reaction plate 91. The spring washer 115 is thus preserved from wear by the retaining washer 118 which closes the groove 117.

As is clearly visible on the Figures 8a, 8b, 9a and 9b , the control lever 65 mounted to pivot connection relative to the support 45 comprises an upper portion 160 mechanically coupled with the switch 64 and a lower portion 161 having two branches 162 forked mounted in a groove 163 of the driver 81. These two parts 160, 161 are interconnected by a connecting portion 165.

More specifically, the control lever 65 has in its upper portion 160 two tabs 166 separated from each other by a slot 167 for passage of the front end of the movable rod 75. Each tab 166 comprises a receiving recess a hinge pin 170 passing through the rod 75 (cf. figure 1 ). The lever 65 is mounted pivotally connected relative to the support 45 of the starter via a pivot axis comprising two sections 172 extending from opposite faces of the connecting portion 165, here made of plastic, advantageously coming from molding with the lever 65. These sections 172 are pivotally mounted for example in a two-piece bearing having a first portion connected to the support 45 and a second portion formed vis-a-vis forming a shim between the contactor 64, more precisely the tank of the latter, and the motor yoke secured to the support 45. For more details, refer to the document for example FRA2699605 .

As is clearly visible on the Figures 9a and 9b , each branch 162 has at its lower end a portion 174, said push portion, adapted to push the driver 81 so as to move the clutch 82 from an unlocked state to a locked state as described in more detail below.

This thrust portion 174 is extended by a protruding cam 175 extending in axial projection relative to the front face of the lever 65. Each cam 175 has a crown portion adapted to bear on the ring 106 in two diametrically opposite zones. thereof to axially move the drive pinion 32 to the starter ring while the clutch 82 is still unlocked. All the shapes of the lever 65 are easily obtained by molding. The lever 65 is made of a rigid thermoplastic material preferably reinforced with fibers.

Furthermore, an intermediate friction reduction element 181 is clearly visible in figure 4 is mounted between the push portion 174 of the control lever 65 and the driver 81. Thus, this configuration makes it possible to dissociate the thrust function of the lever 65 relative to the rotation of the driver 81, which greatly reduces or eliminates the friction between the lever 65 and the driver 81 during a locking phase of the 'clutch.

The intermediate element 181 is constituted by a ball bearing around which is mounted a support transfer part 187. The bearing 181 is mounted around the driver 81 between the shoulder 92 forming the pressure element of the clutch 82 and the rear end of the driver 81. The bearing 181 is positioned slightly recessed relative to the shoulder 92. The support transfer piece 187 allows to transfer a support from the push portion 174 of the lever control 65 to the bearing 181.

For this purpose, the piece 187 comprises a radial flange 188 forming a wall, called pusher, against which bears the thrust portion 174 of the control lever 65 to push the driver 81 towards the reaction plate of the clutch 82 during a locking phase of said clutch, as visible on the Figures 8a and 9a .

Preferably, the support transfer member 187 is locked in rotation relative to the control lever 65. For this purpose, as is clearly visible on the Figures 8a, 8b, 9a, 9b the piece 187 comprises at least two flat-shaped zones 189 formed in its outer periphery against which the internal faces of the branches 162 of the lever 65 face one another. In this case, the support transfer member 187 has four flattened areas so that the piece 187 has a substantially rectangular or square shape in front view.

As is visible on the figure 4 , the bearing 181 is held axially on the one hand by a radial shoulder 190 defined by a slight variation in the outer diameter of the driver 81 and on the other hand by a closure washer 192.

The closure washer 192 has a radial wall 194 called a shooter against which the control lever 65 comes into contact, in particular to move the driver 81 relative to the reaction plate of the clutch 82 during an unlocking phase of said clutch.

The groove 163 of the driver inside which is mounted the lower part of the lever 65 is thus delimited by the two walls of transverse orientation 188 and 194. The section of the groove 163 is generally U-shaped.

As a variant, the support transfer piece 187 has a U-shaped section delimiting the groove 163, the closure washer 192 then being devoid of a shoulder 194.

Moreover, as is visible on the figure 4 a spring 141, here of frustoconical helical shape, bears on one of its axial ends, in this case the end of smaller diameter, against a transverse rear face of the pinion 32. This face of the pinion 32 comprises a shoulder 321 of axial orientation located at the inner periphery of said pinion for centering the spring 141 on the drive pinion 32. The other axial end of the spring 141 of larger diameter bears on the transverse front face of the plate 91. This front face of the plate 91 has a portion inclined in a direction opposite to the drive pinion 32. Such inclination allows the spring 141 to maintain its mechanical properties when in a compressed state.

It is noted that the rear face of the pinion 32 has a corresponding inclination in the direction of the pinion carrier 83 so that the two faces of the plate 91 and the pinion 32 facing each other delimit a substantially frustoconical space in which can the spring 141 is housed in a compressed position. In addition, the front face of the plate 91 has at its outer periphery a shoulder 911 of axial orientation for the radial retention of the spring 141 when the latter is subjected to a centrifugal force. In addition, the pinion carrier 83 comprises an axial stop 142 preferably formed by a circlip mounted in a groove machined in the front end of the sleeve 100. In the rest position of the launcher 31, the spring 141 urges the pinion 32 into position. direction of the axial abutment 142. When the pinion 32 is in abutment on the ring 35 and does not penetrate into it, the spring 141 is compressed and the pinion 32 moves back towards the reaction plate 91.

The operation of the starter 30 according to the invention is described below when the launcher 31 moves from the rest position to the active position and vice versa. In the rest position, the driver 81 being in the uncoupled position, the disks 931, 932, 941-943 are not tightened so that there is an axial play distributed between the pressure element 92, the internal disks 931 , 932 and external 941-943 and the reaction plate 91.

Starting from the rest position and the contactor 64 being electrically powered, the movable core 71 is attracted to the fixed core 72 until it is in a magnetized position. Its displacement simultaneously drives the movable rod 75, the movable contact 69 and the control rod 74 towards the rear.

The lever 65 moved by the movable rod 75 then acts firstly on the ring 106 of the housing 108 via the cams 175 which then move the pinion carrier 83 and the pinion 32 axially in the direction of the ring 35 along the length During this step, the driver 81 is in the uncoupled position so that the pinion 32 is free to rotate in both directions of rotation. The axial movement continues, the pinion 32 arrives in the vicinity of the ring 35.

In a second step, the pinion 32 free in rotation penetrates slightly into the crown 35. During this second step, the thrust portions of the lever 65 come into contact with the flange 188 of the support transfer piece 187 while the portions top cams 175 move away from the ring 106.

The control lever 65 thus axially displaces the shoulder 92 in the direction of the reaction plate 91 of the clutch 82. The displacement of the movable core 71 is such that the movable contact 69 makes contact between the two terminals for supplying the electric motor. . With the electric motor 37 energized, the rotation of the drive shaft 33 drives the driver 81 to the coupled position through the helical splines 84, 85. The forward end of the driver 81 moves to the tray of reaction 91 so that the spring washer 115 is compressed and the clearance between the discs 93, 94 is progressively canceled.

As described above, when the clutch 82 moves from the unlocked state to the locked state, the successive compression of the elastic means 96, 97 allows a stepped passage of the torque via said clutch 82. Thus, initially when the elastic means 96 of lower stiffness is compressed while the elastic means 97 of upper stiffness is decompressed, only part of the faces vis-à-vis the internal disks 931, 932 and external 941-943 vis-à- vis screws are in contact with each other. The torque transmitted by the clutch 82 to the drive ring 35 then corresponds to the intermediate torque threshold S1 (cf. figure 5 ).

In a second step, when the elastic means 96 and 97 are compressed simultaneously, all the faces vis-à-vis the internal disks 931, 932 and external 941-943 are in contact with each other. The torque transmitted by the clutch 82 to the drive ring 35 then corresponds to the final torque threshold S2 (cf. figure 5 ). The clutch 82 is then completely locked for transmission of the torque of the pinion 32 to the crown 35.

Note also that the friction between the control lever 65 and the support transfer part 187 are almost zero when the clutch 82 is locked to the extent that the inner ring 183 of the ball bearing 181 rotatably connected with the driver 81 freely rotates relative to the support transfer member 187 kept stationary in rotation with respect to the control lever 65.

In the case where the pinion 32 is locked in translation in the direction of the ring gear 35 by one or more teeth of the ring gear (tooth-to-tooth position), the control lever 65 continues to move the trainer to bring the disks into contact with each other. friction 931, 932, 941-943. This displacement is made possible by the compression of the spring 141 when the pinion 32 is moved relative to the pinion carrier 83. Where appropriate, the tooth against tooth spring 78 may also be compressed to absorb shocks while applying a force on the lever 65 transmitted to the pinion 32 to the active position.

When the ring gear 35 rotates faster than the shaft 33 carrying the drive gear 32, the friction clutch 82 is released because the driver 81 makes an axial backward movement due to the helical connection between the 81 and the shaft 33. The coach 81 unscrews to move from the coupled position to the uncoupled position. This action is amplified by the spring washer 115 which relaxes and pushes the driver 81 backwards via the retaining washer 118 resting on the end of the driver 81 which slides inside the groove 117. In the event of contact between the reaction plate 91 and the end of the driver 81 during the disengaging phase, the spring washer 115 is protected by the retaining washer 118. In addition, the elastic means 96 and 97 are decompressed successively so as to separate the faces vis-à-vis the internal disks 931, 932 and external 941-943 corresponding.

The return spring 80 acts to return the movable core 71 and the control lever 65 to their rest position visible on the figure 1 . The lever 65 thus moves the thrower 31 backwards by pushing the shooter 194.

According to one example, the launcher comprises only a spring 96 or 97.

Claims (12)

Starter launcher for a motor vehicle engine comprising: - a pinion carrier (83) on which is mounted a drive pinion (32) for meshing with a starting ring gear (35) of a heat engine, a driver (81) mounted on a drive shaft (33),
characterized in that it further comprises a clutch (82) friction interposed between the driver (81) and the drive gear (32) comprising a reaction element (91) integral in rotation with the drive pinion ( 32) and a pressure member (92) integral in rotation with the driver (81), a set of internal disks (931, 932) and external disks (941-943) alternately rotatably connected with the driver (81) and the pinion carrier (83), said pressure member (92) being axially movable with respect to the reaction element (91) for passing said clutch (82) from an unlocked state in which the driver (81) and the pinion carrier (83) are uncoupled in rotation with each other in a locked state in which the driver (81) and the pinion carrier (83) are coupled in rotation with each other , and at least one resilient means (96, 97) arranged between the pressure element and the reaction element, the elastic means being arranged to allow a stepped transmission of the torque by the clutch (82) when said clutch (82) changes from unlocked state to locked state. A launcher according to claim 1, wherein the resilient means is arranged so that when the clutch is between the unlocked and locked state, the resilient means allows only part of the inner (931, 932) and outer (941- 943) allow a passage of torque to an intermediate torque threshold by being in contact with each other and that in the locked position the elastic means allows the set of internal and external disks to be in contact to allow passing a torque up to a final torque transition threshold (S2) greater than the intermediate torque transition threshold (S1). Launcher according to claim 1 or 2, characterized in that the elastic means (96, 97) is able to pass: a decompressed state in which the resilient means (96, 97) prevents contact between at least one face of an internal disk (931, 932) and at least one face of an external disk (941-943); ) corresponding, in a compressed state in which the face of the inner disk (931, 932) and the face of the corresponding outer disk (941-943) are in contact with each other to increase the level of torque passed through the clutch . Launcher according to one of claims 1 to 3, characterized in that it comprises a single elastic means (96, 97) positioned between two internal disks or two successive external disks. Launcher according to one of claims 1 to 3, characterized in that it comprises two elastic means (96, 97) having different stiffnesses each positioned between two internal disks (931, 932) or two external disks (941-943) successive, so that when the clutch (82) moves from an unlocked state to a locked state, in a first step, the elastic means (96) of lower stiffness is compressed while the elastic means (97) of upper stiffness is decompressed so as to obtain the intermediate threshold of torque passage (S1), and in a second step, the elastic means (96, 97) of lower and upper stiffness are compressed simultaneously so as to obtain the final threshold of passage of torque (S2). Launcher according to one of Claims 1 to 5, characterized in that it comprises an elastic means (96, 97) positioned between the pressure element (92) and one of the disks connected in rotation with the pinion carrier (83). ). Launcher according to one of Claims 1 to 6, characterized in that it comprises an elastic means (96, 97) positioned between the reaction element (91) and one of the disks connected in rotation with the driver (81). Launcher according to one of claims 1 to 7, characterized in that the elastic means (96, 97) are each constituted by a spring washer (115). Launcher according to one of claims 1 to 8, characterized in that it comprises three external disks (941-943) and two internal disks (931, 932). Launcher according to one of claims 1 to 9, characterized in that it comprises an intermediate friction-reducing element (181) to be mounted between the driver and a portion (174) of a control lever (65). ). Launcher according to one of claims 1 to 10, characterized in that it comprises a frustoconical spring (141) mounted in support on the one hand against one side of a transverse plate (91) of the pinion carrier and on the other against one side of the drive sprocket (32). Motor vehicle engine starter with a launcher according to one of the preceding claims.

Images