WO2016198773A1 - Starter for a motor vehicle equipped with an internal combustion engine - Google Patents

Abstract

The present invention relates to a starter (1) for a motor vehicle comprising: a starter drive assembly (3) comprising a pinion (5), a casing (9) containing an electric motor (7) intended to drive the rotation of the pinion (5), a contactor (13) intended to move the starter drive assembly (3) via a fork (21) in order to engage the pinion (5) in an engine ring gear (6) at the time of a start, in which, in at least a position of engagement of the fork (21), said fork (21) presses against an element secured to the casing (9) via a flexible element (24', 24").

Description

 MOTOR VEHICLE STARTER PROVIDED WITH AN ENGINE

 INTERNAL COMBUSTION

The present invention relates to the field of starters and in particular starters for a motor vehicle.

 The starters comprise a launcher on which is mounted a gear for engaging with a ring of the engine to start, an electric motor for driving the pinion in rotation and a switch for moving the launcher via a fork to allow movement from the pinion to the crown. The contactor also controls the power supply of the electric motor. The contactor includes coils that move a magnetic core connected to the fork when energized.

 Moreover, to ensure a good gear of the pinion on the crown, a great race launcher and a great strength are necessary. This implies a large gap at the contactor and therefore high power coils to ensure sufficient strength. However, such coils involve a high energy consumption which increases the overall consumption of the motor vehicle.

It is necessary to find a solution to reduce the consumption of the contactor while ensuring proper operation of the starter and in particular a good gear of the pinion on the crown.

For this purpose, the present invention relates to a starter, particularly a motor vehicle, comprising:

a launcher comprising a pinion,

 - a cylinder head enclosing an electric motor for driving the pinion in rotation, - a switch for moving the launcher via a tilting fork to engage the pinion in a motor ring during a start, the switch comprising a movable core and a spring tooth-tooth located at the mobile core, to facilitate the gearing of the pinion on the motor ring, located at the mobile core,

in which, in at least one engagement position of the fork, said fork is in abutment against an element integral with the breech by means of a flexible element, and

 and wherein the flexible member has a modulus of elasticity less than the modulus of elasticity of the tooth-tooth spring (29).

The flexible support makes it possible to modify the angle of the fork to reduce the stroke of the movable core during the tooth-tooth contact and thus reduce the consumption of the contactor and this allows the flexible support to be deformed before the tooth-tooth spring.

According to another aspect of the present invention, the integral member of the yoke may be a part of the yoke or a reduction ring of the starter or an intermediate element mounted against the yoke or a carcass element of the starter connected to the yoke.

According to an additional aspect of the present invention, the flexible element has a modulus of elasticity in compression of less than 1000 MPa.

 Such a flexible element can be deformed during the advancement of the movable core of a contactor such as for a car. However, in the case of a movable core with tooth tooth spring it is further necessary that the elasticity modulus of the flexible element is lower than that of the tooth-tooth spring.

According to one embodiment, the pinion is movable in translation relative to the launcher and comprises a tooth-tooth spring compressed between the pinion and a shoulder of the launcher, and in that the flexible element has a modulus of elasticity lower than the module elasticity of the tooth spring.

According to another aspect of the present invention, the flexible element is made of elastomer and / or rubber. This allows a particle such as a piece of broken part to disturb the operation of the elastic element.

According to one preference, the flexible element is made of rubber and can be overmolded on the element integral with the cylinder head. This makes it possible to have no additional operation to be performed on the starter assembly line. According to other embodiments, the flexible support can be achieved by a spring or a belleville washer (spring washer).

 According to a further aspect of the present invention, the flexible member is attached to the fork.

This allows such a range can adapt to different types of starter.

 According to an additional aspect of the present invention, the flexible element is disposed on the element integral with the cylinder head.

 This makes it possible to integrate a standard range.

 According to another aspect of the present invention, there are several points of support between the fork and the element integral with the yoke as a function of the inclination of the fork with respect to the yoke.

 This makes it possible to vary the ratio of the lever in such a way that the force varies so that the lever applies a force to the launcher during the engagement phase (initial position at a gearing position, the gearing position is between tooth tooth position and the final position, for example at least two minima after tooth tooth position) of the pinion in the motor ring greater than the force to push the pinion in a gear phase that moves to its final position. The ratio is measured according to the ration of the distance between the pivot point of the fork on the yoke and the pivot point of the fork on the movable core divided by the distance between the pivot point of the fork on the cylinder head and the point of contact with the launcher. (The point of contact on the launcher may vary.)

 Thus, a greater lever ratio is used for the engagement phase than the intermesh phase. Thus, it is possible to reduce the stroke of the mobile core during the intermesh phase. This allows less power consumption.

Thus, the first example of application is the reduction of the stiffness of the tooth-tooth spring while ensuring that the pressure applied by the pinion against the motor ring during the engagement phase is the same as with a fork to one. single point of support.

A second example of application is the reduction of the size of the axial air gap of the contactor during tooth-tooth contact with the motor crown while obtaining the same displacement of the launcher and the same pressure force of the pinion against the motor crown. .

According to one aspect of this embodiment, there are at least first and second points of pivots of the fork on at least respectively a first and second element secured to the yoke and in that at least the first pivot point is supported by means of the flexible element on at least one integral element and in that the two points of pivots are arranged so that the pinion arrives in position tooth against tooth with the motor ring just before the second pivot point comes into contact with the second support element.

 This allows to additionally reduce the size of the air gap of the contactor while obtaining the same displacement of the launcher, to continuously dissipate the kinetic energy accumulated by the movable core in the flexible support and in the spring tooth and then during the transition to the rigid support, the mobile core has less energy to dissipate via the tooth-tooth spring. In addition, more movement of the movable core is used to move the launcher and thus the pinion to the engine crown. This improves the overall kinematics of the pinion.

In addition, the flexible support, in the compressed state, with the fork that provides a leverage between the rigid pivot point and the flexible point participates as the tooth-tooth spring to push the pinion against the motor ring. The stiffness of the tooth-tooth spring can then be reduced to thereby reduce the contactor consumption

According to a further aspect of the present invention, the fulcrum between the fork and the yoke moves continuously as a function of the inclination of the fork.

 This allows for a greater leverage to overcome the launcher's inertia to its original position. According to an additional aspect of the present invention, the hardness of the element on which the support is made between the fork and the element integral with the yoke varies as a function of the position of the fulcrum.

According to another aspect of the present invention, the part of the fork intended to be in contact with the launcher comprises an end cam with a plurality of different curvatures, said end cam being configured to obtain a constant leverage ratio or growing during the switchover.

This allows a faster gear of the pinion on the motor ring. This makes it possible to vary the ratio of the lever in such a way that the force that the lever applies to the launcher is maximum during the engagement phase (from the initial position to the meshing position) of the pinion in the driving ring then enough to push the pinion to its final position.

Thus, the first example of application is the reduction of the stiffness of the tooth-tooth spring while ensuring that the pressure applied by the pinion against the motor ring during the engagement phase is the same as with a fork to one. single point of support. A second example of application is the reduction of the size of the gap of the contactor during tooth-tooth contact with the motor crown while obtaining the same displacement of the launcher and the same pressure force of the pinion against the motor ring.

 Other features and advantages of the invention will appear in the description which will now be made, with reference to the accompanying drawings which represent, by way of indication but not limitation, a possible embodiment. On these drawings:

FIG. 1 represents a view in longitudinal section of a starter,

 FIG. 2 represents a sectional view of a portion of a starter comprising a fork with a double pivot,

FIG. 3 represents a diagram of a fork comprising a double pivot,

 FIG. 4 represents a side view of a fork with a single pivot,

 FIGS. 5a to 5c represent different positions of a pivot of a fork comprising a cam;

 FIG. 6 represents a diagram of the starter of FIG. 2 when the fork is resting on its first pivot point and the pinion at a distance from the driving ring,

 FIG. 7 represents a diagram of the starter of FIG. 2 when the pinion is tooth against tooth with the motor crown.

- Figure 8 shows a diagram of the starter of Figure 2 when the pinion is meshed. The following achievements are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a particular embodiment. only embodiment. Simple features of different embodiments may also be combined to provide other embodiments.

FIG. 1 represents a diagram of a starter 1. The starter 1 comprises a launcher 3 on which is mounted a pinion 5 designed to engage a ring gear of a motor to be started, called the motor ring gear. The pinion 5 is rotated. by an electric motor 7 arranged in a cylinder head 9. The driving of the launcher 3 is carried out via a reducing ring 11 disposed at the end of the cylinder head 9. The starter 1 also comprises a contactor 13 comprising at least one coil 15 allowing moving the movable portion of a magnetic core or movable core 17 to the fixed portion 16 of the magnetic core within an air gap 19 so as to axially move the launcher 3 through a fork 21. In general, using two coils, a call coil to move the movable core 17 and a holding coil to keep the movable core 17 close to the fixed part 16 of the magnetic core. In the following description we will limit to designate a coil 15 (which can therefore include several coils).

The fork 21 comprises a first end 21a attached to the movable core 17 of the contactor 13. The connection between the fork 21 and the movable core 17 can be done by any suitable means to transmit the force between the fork 21 and the movable core 17 as per example a hitch pin. The second end 21c of the fork 21 comes into contact with the launcher 3 to allow the axial displacement of the launcher 3. The contact is for example at a flange 22 of the launcher 3 configured to receive the end 21c of the fork 21 over the entire displacement of the launcher 3, the point of contact between the end 21c of the fork 21 and the flange 22 varying during the tilting of the fork 21 causing the axial displacement of the launcher 3. The fork 21 also comprises a central portion 21b comprising a pivot point 23 intended to come against a support element 24. The support element 24 is for example fixed on the yoke 9 of the starter 1 or on the reducing ring 11. In the absence of power of the contactor 13, a return spring 27 constrains the mobile core 17 in a rest position in which the gap 19, that is to say the distance between the fixed portion 16 of the magnetic core and the movable core 17, is maximum. In this rest position, the fork 21 is generally not in contact with the support element 24. The fork 21 is for example made of rigid plastic as per for example a thermoplastic (PA66 GF30). Such a fork has a modulus of elasticity greater than that of the flexible element and in particular when there is a spring tooth tooth, this spring tooth tooth. Thus, the supply of the coil 15 of the contactor 13 causes the displacement of the movable core 17 in the air gap 19 as indicated by the arrow 26, which causes, in a first step, the movement of the fork 21 to the contact with the support element 24 which corresponds to the beginning of the engagement of the fork 21 with the support element 24. During this first time, the launcher 3 remains stationary. This first phase allows the mobile core 17 to accelerate without resistance. In a second step, the pivot point 23 comes into contact with the support element 24 as shown in FIG. 1, which causes the fork 21 to tilt around the pivot point 23 and moves the thrower 3 axially along the X axis as indicated by the arrow 28 (see Fig. l). This axial displacement of the launcher 3 causes the pinion 5 to move towards the ring gear 6 of the engine to be started. Thirdly, the pinion 5 comes into tooth-to-tooth contact with the driving ring gear 6 which causes the compression of a tooth-tooth spring 29 situated at the level of the movable core 17 until the gap 19 is closed. which causes the starting of the electric motor 7 and thus the rotation of the pinion 5 which can then mesh with the motor ring 6, in particular thanks to the action of the tooth-tooth spring 29.

In order to limit the power of the coil 15, the support element 24 is a flexible element, that is to say an element whose modulus of elasticity is less than the modulus of elasticity of the tooth-tooth spring 29 , for example a modulus of elasticity in compression less than 1000 MPa. The flexible element is for example made of elastomer or rubber or in a mixture of elastomer and rubber. In fact, the use of a flexible support element that will compress before the compression of the tooth-tooth spring 29 makes it possible to modify the angle of the fork 21 and to reduce the stroke of the movable core 17 during the tooth contact against tooth between the pinion 5 and the driving ring 6.

Furthermore, it should be noted that instead of using a support member 24 which is flexible, it is also possible to place the flexible element at the pivot point 23 of the fork 21 or an element intermediate element disposed between the fork 21 and the support element 24. The support element 24 is integral with the cylinder head 9 or an element attached to the cylinder head 9, for example a carcass 31 of the starter 1 or the crown reducing 11. FIG. 2 represents a second embodiment of a starter 1 according to the present invention in which the fork 21 comprises a first 23 'and a second 23 "pivot points associated with a first 24' and a second 24" elements respectively. support so that during the displacement of the movable core 17, the fork 21 tilts in a first time according to the first pivot point 23 'and in a second time according to the second pivot point 23 ". The support between the first point 23 'and the first support element 24' being formed by means of a flexible element as described in the previous embodiment, the two support elements 24 'and 24 "are integral with the cylinder head 9 and are fixed for example directly on the cylinder head 9 or on the reduction ring 11 or on the carcass 31 of the starter 1. As for the first embodiment, the flexible element may be the first support element 24 'or an element from the first pivot point 23 'of the fork 21 or an intermediate element disposed between the fork 21 and the first support element 24'.

Furthermore, it should be noted that the starter of FIG. 2 is an outgoing starter, unlike the starter 1 of FIG. 1, the present invention being applicable to the various types of starters.

FIG. 3 represents an exemplary embodiment of a fork 21 comprising a first 23 'and a second 23 "pivot point, the first pivot point 23' being made by a flexible element, for example an elastomer element or a component. This flexible element is for example fixed by gluing on the fork or overmolded.

Preferably, the first 23 'and second 23 "pivot points as well as the first 24' and second 24" bearing elements are configured so that the pinion 5 arrives in the tooth against tooth position with the motor ring 6 just before that the second pivot point 23 "comes into contact with the second support element 24". Such a configuration makes it possible to reduce the size of the air gap 19 of the contactor 13 while obtaining the same displacement of the launcher 3.

Moreover, to improve the efficiency of the starter 1, the part of the second end 21c of the fork 21 intended to push the launcher 3 may be provided with an end cam 33 comprising a plurality of sections with radii of curvature different or a set of segments with different orientations so as to obtain a report of constant or even increasing lever when tilting the fork 21 while the lever ratio is decreasing with a radius of curvature contant.

As shown in FIG. 4, the lever ratio d2 / d1 is defined by the ratio of the distance d2 between the axis XI passing through the pivot point 23 and the axis X3 passing through the fulcrum 35 of the fork 21 on the launcher 3 with the distance dl between the axis XI passing through the pivot point 23 and the axis X2 passing through the point of attachment 37 of the fork 21 on the movable core 17. Thus, the ratio of lever obtained with the end cam 33 provides a maximum effort at the point of support 35 on the launcher 3 at the start of the launcher 3, which better overcome the inertia of the launcher 3 of one part and increase the pressure force of the pinion 5 against the ring 6 on the other hand.

According to an alternative embodiment shown in Figures 5a to 5c, it is also possible to have a multitude of pivot points 23 and support points 24 using a cam 39 at the pivot point 23. The point of support between the fork 21 and the support member 24 then moves continuously according to the inclination of the fork 21. The pivot point 23 is divided into a first 23a and a second 23b parts, the first part 23a being formed by a flexible element so that the support between the cam 39 and the fulcrum 24 is flexible on at least a portion of the cam 39 and the second part being made by a rigid element, c ' that is to say an element whose modulus of elasticity is greater than the modulus of elasticity of the tooth-tooth spring, for example a modulus of elasticity in compression greater than 3000 MPa. It is also possible to divide the cam 39 into a number of parts greater than two, the different parts may have different elastic moduli ranging from the most flexible to the most rigid. The flexible elements may also be arranged on the support element 24 or on an intermediate element. The cam 39 is not limited to an arcuate shape but may also have several radii of curvature or a set of non-parallel segments.

FIGS. 5a to 5c show three positions of the cam 39 corresponding to three positions of the mobile core 17. The first position (FIG. 5a) represents a position at the beginning of travel of the mobile core 17 when the coil 15 has just been powered, the contact is made at the first part 23 of the pivot point 23, that is to say at the level of the flexible part. The pivot point 23 will therefore collapse due to the flexibility of the portion 23a. The second position (FIG. 5b) represents a position in the middle of the race of the mobile core 17 substantially when the pinion 5 is found tooth against tooth with the motor ring 6. This position corresponds to the transition between the first 23a and the second part 23b of the pivot point 23 and thus the transition to a rigid support. The third position (Figure 5c) represents an end position of the movable core 17 when the gap 19 is reduced. The support is then performed at the second portion 23b of the pivot point 23, that is to say at the rigid portion of the pivot point 23.

The use of at least two pivot points 23 ', 23 ", 23a, 23b, one of which is flexible, continuously dissipates the kinetic energy accumulated by the mobile core 17 in the flexible support and in the Thus, when moving to the rigid support, the mobile core 17 has less energy to dissipate via the tooth-tooth spring 29. In addition, more travel of the movable core 17 is used to move the launcher 3 and thus the pinion 5 to the engine crown 6. This improves the overall kinematics of the pinion 5.

In order to better understand the present invention, the different phases of starting a starter 1 comprising a first 23 'and a second 23 "pivot points and a first 24' and a second 24" support elements 24 'and 24 " whose support between the first pivot point 23 'and the first support element 24' is a flexible support will now be described from Figures 2 and 6 to 8.

The first phase concerns the supply of the coil 15 of the contactor 13. This supply triggers the displacement of the mobile core 17 towards the fixed part 16 of the magnetic core as indicated by the arrow 26 of FIG. 2. During this first phase, the launcher 3 remains stationary and the mobile core 17 accelerates without resistance.

The second phase concerns the contacting between the first pivot point 23 'and the first support element 24' as shown in FIG. 2. The flexible element, for example the first pivot point 23 'and / or the first support element 24 'is then compressed by the displacement of the movable core 17. In addition, the contact between the fork 21 and the first support element 24' triggers the tilting of the fork 21 around the first pivot point 23 which triggers the displacement of the second end 21c of the fork 21 which then comes into contact with the flange 22 of the launcher 3. In the third phase shown in FIG. 6, the displacement of the movable core 17 continues to tilt the fork 21 around the first pivot point 23 'which triggers the displacement of the launcher 3 towards the crown 6 as indicated by the arrow 28.

In the fourth phase shown in Figure 7, the displacement of the movable core 17 in the gap 19 to approach the fixed portion 16 of the magnetic core continues so that the pinion 5 comes tooth against tooth with the motor ring 6 which triggers the compression of the tooth-tooth spring 29 and the total compression of the flexible support. In addition, the fork 21 comes into contact with the second support element 24 "The support of the fork 21 being rigid and the pinion 5 being tooth against tooth with the motor ring 6, the displacement of the movable core 17 causes the compression of the tooth-tooth spring 29.

The fifth step represented in FIG. 8 corresponds to the closing of the air gap 19. The mobile core 17 is then in contact with the fixed part 16 of the magnetic core which triggers the supply of the electric motor 7 and drives the launcher 3, and in particular the pinion 5, in rotation. This rotation of the pinion 5 combined with the action of the toothed spring 29 which has been compressed and of the compressed soft support which forces the pinion 5 against the motor ring 6 to return to the rest position causes the rapid gearing of the pinion 5 on the ring 6. Once the pinion 5 geared on the motor ring 6, the torque of the electric motor 7 can be transmitted to the motor ring 6 to start the engine which is attached the motor ring 6.

Thus, the use of a flexible element at the point of contact between a pivot point 23, 23 ', 23a of the fork 21 and a support element 24, 24' against which the fork 21 tilts allows, by modifying the angle of the fork 21 to reduce the energy required to trigger the movement of the launcher 3 and thus reduce the power required for the coil 15 of the contactor 13 while ensuring an effective gear of the pinion 5 on the motor ring 6 .

In addition, the use of a flexible element is advantageously combined with a fork 21 comprising several pivot points 23 ', 23 "so as to further reduce the energy required for starting and thus reduce the power of the coil even more. 15. According to one embodiment, the flexible element is attached to the fork. This allows such a range can adapt to different types of starter.

 For example, the pivot point 23 is in a softer material than the fork and the fulcrum. In this case, this pivot point is an insert on the fork and comprises a modulus of elasticity lower than the modulus of elasticity of the tooth-tooth spring 29.

In another example, the pivot point 23 'is formed by a flexible member. In this case, the first support element is not necessarily in a material having a modulus of elasticity lower than that of the tooth-tooth spring. The second pivot point 23 "is an element whose modulus of elasticity is greater than the modulus of elasticity of the tooth-tooth spring, it can still deform anyway under the effect of the support of the fork on It follows that in the hardness of the element on which is made the support between the fork 21 and the integral element of the cylinder head 9 varies depending on the position of the fulcrum.

Claims

Motor vehicle starter (1) comprising:  a launcher (3) comprising a pinion (5),  - a yoke (9) enclosing an electric motor (7) for driving the pinion (5) in rotation,  - A switch (13) for moving the launcher (3) via a fork (21) to engage the pinion (5) in a motor ring (6) during a start, the contactor comprising a movable core (17) and a tooth-tooth spring (29) located at the movable core (17), to facilitate the gearing of the pinion (5) on the motor ring (6), located at the mobile core (17),  characterized in that, in at least one engagement position of the fork (21), said fork (21) bears against an element secured to the yoke (9) by means of a flexible element,  and wherein the flexible member has a modulus of elasticity less than the modulus of elasticity of the tooth-tooth spring (29). 2. Starter (1) according to claim 1 wherein the element integral with the yoke (9) may be a part of the yoke (9) or a reducing ring (11) of the starter or an intermediate element mounted against the cylinder head ( 9) or a carcass element (31) of the starter connected to the cylinder head (9). 3. Starter (1) according to claim 1 or 2 wherein the flexible element has a modulus of elasticity in compression less than 1000 MPa. 4. Starter (1) according to one of the preceding claims wherein the flexible element is made of elastomer and / or rubber. 5. Starter (1) according to one of the preceding claims wherein the flexible element is attached to the fork (21). 6. Starter (1) according to one of claims 1 to 4 wherein the flexible element is disposed on the element integral with the yoke (9). 7. Starter (1) according to one of the preceding claims wherein there are several points of support between the fork (21) and the element integral with the yoke (9) according to the inclination of the fork ( 21) with respect to the cylinder head (9). 8. Starter (1) according to claim 7 wherein the point of support between the fork (21) and the yoke (9) moves continuously according to the inclination of the fork (21). 9. Starter (1) according to one of claims 7 or 8 wherein the hardness of the element on which is made the support between the fork (21) and the integral element of the yoke (9) varies depending the position of the fulcrum. 10. Starter (1) according to one of the preceding claims wherein the portion of the fork (21) intended to be in contact with the launcher (3) comprises an end cam (33) with a plurality of different curvatures, said end cam (33) being configured to allow a fast gear of the pinion (5) on the motor ring (6).