FR3069982A1 - BROOM DOOR FOR MOTOR VEHICLE STARTER - Google Patents

Abstract

Brush holder (10) for a starter (201) of a motor vehicle, the brush holder (10) being provided with an X axis and comprising: a support plate (12) comprising a metal plate (121) having a first polarity and a melting element (122) electrically insulating on the metal plate (121); a brush (15.1, 15.2, 15.3, 15.4) having a second polarity different from the first polarity; a broom (13.1, 13.2, 13.3, 13.4) mounted on the support plate (12), the cage comprising: - a cage body (39) receiving the blade (15.1, 15.2, 15.3, 15.4), a fixing lug (32) resting on the melting element (122) of the support plate (12). It is expected that the metal plate (121) comprises at least one recess (43) covered by the melting element (122) and that the fastening tab (32) bears against the melting element (122). the support plate (12) in the area of the recess (43).

Description

BRUSH HOLDER FOR MOTOR VEHICLE STARTER

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a brush holder for a motor vehicle starter and a starter comprising such a brush holder.

TECHNOLOGICAL BACKGROUND

Motor vehicles comprising a heat engine also include a device for starting this heat engine, called a starter.

There is shown in Figure 1 a section of a starter 201 for an internal combustion engine of a motor vehicle according to the prior art.

This starter 201 comprises a contactor 217 and an electric motor 1 provided on the one hand with a rotor 202, also called armature, comprising an axis X and which can rotate around this axis, and on the other hand, with a stator 211 , also called inductor, placed around the rotor 202. This stator 211 comprises a yoke 7 of the starter and comprises at least one pole piece 204 for the installation of an inductor winding 4 or magnets.

The rotor 202 comprises a rotor body 207, an armature winding 208 wound in notches of the rotor body 207 and an armature shaft 214.

The armature winding 208 forms, on either side of the rotor body 207, a front bun 209 and a rear bun 210.

The rotor 202 is provided, at the rear, with a collector 212 fixed on the armature shaft 214 comprising a plurality of contact parts electrically connected to the conductive elements, formed in the example considered by wires or pins, armature winding 208. The manifold 212 of the electric motor 206 is surrounded by the cylinder head 7.

Brushes 15.1, 15.2, 15.3 and 15.4 of which only two, namely 15.1 and 15.3 are visible in FIG. 1, are provided for the electrical supply of the armature winding 208. The brushes 15.1, 15.2, 15.3 and 15.4 forming a group and are each carried by a brush holder 10 sandwiched between the cylinder head 7 and a cover 216 forming a rear bearing for the rotor shaft of the electric machine. At least one of the group brushes being connected to the starter ground here, for example 15.2 and 15.4 and at least one of the group brushes being connected to the contactor 217 here, for example 15.1 and 15.3. A group of 4 brushes 15.1 - 15.4 is provided here. However, the brushes can also be, for example, two, six or eight in number.

The contactor 217 comprises a terminal 229 connected via an electrical connection element, for example a wire 230, to an electrical supply of the vehicle.

The contactor comprises a terminal 3 connected via an electrical connection element, for example a wire 226 to at least one of the brushes 15.1 - 15.4. One could also provide that the terminal 3 is connected via the inductor winding 4 to at least one of the brushes.

The brushes 15.1 - 15.4 rub against the collector 212 when the rotor 202 is in rotation.

The starter 201 further includes a launcher 219 slidably mounted on a drive shaft 218 and capable of being rotated around the axis X by the rotor 202.

The launcher 219 comprises a drive element forming a pinion 221 and intended to engage on a drive member 274 of the combustion engine. This drive member is for example a toothed crown.

A speed reducer assembly 220 can be interposed between the rotor 202 and the drive shaft 218. In any event, the rotor 202 can cause the rotation of the pinion 221 by its rotation. The rotation of the rotor also corresponds to that of the collector 212 within the brush holder device 10. According to one type of starter the collector rotates clockwise relative to the brushes, according to another type of starter, the collector rotates counterclockwise relative to the brushes.

The launcher 219 also comprises a pinion holder which is not visible in FIG. 1. The pinion 221 can be slidably mounted in translation along the axis X on this pinion holder or fixed on this pinion holder.

The launcher 219 further comprises a free wheel 222 and a pulley washer 223 defining between them a groove 224 for receiving the end 225 of a fork 227.

This fork 227 is produced for example by molding a plastic material.

The fork 227 is actuated by the contactor 217 to translate the launcher 219 relative to the drive shaft 218, along the axis X, between a first position in which the launcher 219 is disengaged from the ring gear 274 and a second so-called engagement position in which the launcher 219 drives the combustion engine via the pinion 221.

So that the pinion 221 can drive the ring gear of the heat engine 274, the teeth of the pinion must, after translation of the pinion and the starter along the X axis, reach the position of engagement. According to this engagement position, a tooth of the pinion is arranged between two teeth of the crown.

The pinion 221 then drives the crown 274 in a direction called positive direction which has the effect of causing when the pinion 221 rotates at a certain speed, the starting of the heat engine.

After the engine has started, the crown 274 continues to rotate in said positive direction. It then drives the pinion but not the rotor 202 thanks to the freewheel 222.

In fact, the freewheel 222 is disposed between the rotor 202 and the pinion 221 to allow transmission of the torque from the rotor 202 to the pinion 221 and the crown 274 when the latter is driven in the positive direction by the pinion. On the contrary, when the crown 274 rotates in the positive direction and drives the pinion 221, the rotor 202 is not driven.

FIG. 2 shows in a simplified representation an example of a starter motor 1 comprising a fuse 2 connected upstream with respect to the brushes, the current going from the brushes to the collector 212. For example, the fuse 2 is mounted in series between the terminal supply 3 and windings 4.1, 4.2, 4.3, 4.4 of the winding 4 of said motor. The fuse is intended to blow to cut off the electrical supply to the motor when it is traversed by a maximum predetermined current. This is to prevent damage to the starter or its surroundings due to the heat produced by an overcurrent. Such an overcurrent appears in particular in the case where the rotor of the motor is locked in rotation. When the machine is running at no load or at low load (that is to say, it operates between 0 and 25% of the nominal load), the no load speed of the rotor also causes the electric motor to heat up 1 likely to damage the starter 201 over time. This heating, due in particular to the mechanical friction between the brushes 15.1 to 15.4 and the collector 212, occurs for example in the event of a malfunction and that the pinion does not enter the crown. However, in this case, the current flowing through the fuse may be too low to cause the fuse 2 to blow, even over a long period. Even so, this overheating can reach 200 ° at the cylinder head or 300 ° at the brushes and can ignite starter components including starter sheaths, the brush holder and cause a fire in the car or component deformations in the car due to overheating or flames. There is therefore a need to cut the starter circuit to suppress the supply of the electric motor in order to reduce the risk of fire when the heating to cause a temperature in the starter exceeding a threshold value corresponding to a temperature below the temperature. critical that could ignite sheaths or the brush holder.

A first solution consists in choosing a fuse 2 capable of blowing both when a no-load current flows through the fuse for a duration exceeding a first predetermined duration and when a current flows through the rotary electrical machine having its rotor blocked for a duration exceeding a second predetermined duration. Such fuses are however much larger than a standard size fuse, which makes their integration almost impossible in the starter.

The document FR2977408 describes a second solution comprising a compact thermal protection system 5 making it possible to cut the electrical supply to the motor in the two aforementioned cases (in the event of blockage and in the event of operation at low load). To this end, this system 5 comprises a heat-sensitive member and a contact blade capable of establishing, following a deformation of the heat-sensitive member, a short circuit between a positive polarity to which the positive brushes are connected 15.1 ,

15.3 and the starter cylinder head 7 connected to earth with the brushes 15.2 and 15.4. However, a spring inside the brush cage implies, at iso diameter of the cylinder head, the use of a shorter brush and therefore a more limited lifespan of the starter. The use of reinforced starters to restart a heat engine when it has just been stopped for example at a red light requires a number of brush cycles greater than the brushes of this prior art.

A third solution is described in Figures 3 to 9. More specifically Figure 3 shows a brush holder 10 according to the third solution for a motor vehicle starter operating with a fuse 2 connected upstream relative to the brushes, the current going from the brushes towards the collector 212. This brush holder 10 comprises a support plate 12 of substantially annular shape on which is fixed a set of cages 13.1-13.4 each serving as a housing for a brush 15.1-15.4. An axis X of the support plate 12 corresponds to the axis of the brush holder 10.

As can be seen in Figure 3, the brush holder comprises springs 35 mounted on antennas 37. Each spring 35 has a coiled portion formed by a plurality of turns. The rolled-up part ends in an arm 351 intended to come into abutment against at least part of the rear face of the brush 15.1-15.4. In this case, the arm 351 is terminated by two parts 352 in contact against bearing faces 38 located on either side of the zone for fixing a braid 24.1-24.4 electrically conductive to the brush. The attachment area between the braid 24.1-24.4 and the broom

15.1-15.4 is set back from the bearing faces 38 in order to maximize a functional distance for using the brushes 15.1-15.4. The brushes 15.115.4 have alternating polarities. So for example brushes 15.1 and

15.3 of positive polarity are electrically connected, via their respective braid

24.1, 24.3 to a supply wire coming from the starter contactor.

As is clearly visible in FIGS. 4 and 5, the support plate 12 is a single piece comprising a metal plate 121 and overmolded layers 122 produced on either side of the metal plate 121. The overmolded layers 122 are produced by means of a plastic material ensuring good electrical insulation. The overmolded layers 122 at least partially protect the brush support face as well as the opposite face. The overmolded layers 122 cover all the risk areas of the metal plate 121, that is to say, all the areas where a short circuit could appear.

The overmolded layers 122 are heat sensitive and deformable from a predetermined temperature. The predetermined temperature corresponds to a temperature above which the starter and / or its environment would be liable to be damaged. For example, the predetermined temperature is greater than 200 ° C, for example 265 °. Different plastics can be used depending on the applications and the constraints imposed on them. Typically, the plastic material used for the overmolded layers 122 is a thermoplastic material such as a polyamide PA4.6 or PA6.6 or a polypropylene PPS loaded with glass fiber between 40 and 50%. The metal plate 121 is typically obtained by stamping from a cutting steel such as, for example, FePO5. In addition, the central part of the plate 12 has an orifice 14 through which the brush holder 10 is mounted around the rotor shaft of the starter. The plate 12 includes openings 33 for the passage of fixing lugs 32 of the cages 13.1-13.4.

The brushes 15.1 and 15.3 and their corresponding cage 13.1 and 13.3 are electrically isolated from the negative polarity for correct operation of the starter by the overmolded layers 122 which cover the openings 33 receiving the legs of the cages of positive polarity 13.1, 13.3, as well as at least in part the inner contour of the plate 12. The braids 24.1 and 24.3 may also be covered with an insulating sheath.

Furthermore, the brushes 15.2 and 15.4 of negative polarity intended for the current return are electrically connected to the ground of the machine by means of their respective braid 24.2, 24.4 welded to the metal plate 121. The flexible braids 24.1-24.4 are advantageously in copper or copper alloy to facilitate welding on the plate 121.

For example, the openings 33 receiving the tabs 32 of the cages of negative polarity 13.2 and 13.4 as well as the zones of the internal contour of the plate 12 in contact with the other tabs 32 of these cages 13.2, 13.4 may not be electrically insulated, in so that an electrical contact can occur between the cages of negative polarity 13.2, 13.4 and the plate 121 via the lugs 32. This contact is not harmful to the operation of the starter, insofar as it participates in establishing contact between the parts intended to be at the same potential, in this case the ground potential in this application.

The tabs 32 of the cages of positive polarity 13.1, 13.3 may be covered at least in part with an insulating layer sensitive to heat. This layer forming a deformable member can be made of the same type of material as that of the overmolded layers 122.

Each brush 15.1-15.4 is slidably mounted inside a cage

13.1-13.4 which is open on the side of the X axis to allow electrical contact of the brushes 15.1-15.4 with blades (not shown) carried by the collector 212.

Figures 6 and 7 each illustrate one of the cages 13.1-13.4 of a certain type of starter depending on whether the manifold 212 rotates counterclockwise or clockwise relative to the brushes.

The cage 13.1-13.4 is produced by folding a thin sheet plate so as to substantially form an omega, the end branches of which are fixed to the plate 12.

Each cage 13.1-13.4 thus has two side walls 17, 18 which are parallel to one another connected to each other by an upper wall 19. It also includes two flanges 20, 21 corresponding to the branches of the omega stem from the lower edges of the side walls 17, 18 of the broom cage 13.1-13.4. One of the side walls 17 has a notch 23 to allow the passage of the braid 24.1-24.4 of the brush housed in the corresponding cage 13.1-13.4. The other side wall 18 has an opening 25 to allow the passage of the arm of the corresponding spring. On the side of the face opening on the side of the collector 212, each brush cage

13.1-13.4 may include flaps 28, 29 extending on either side of the brush to prevent dust generated by friction with the collector blades from affecting the operation of the brush holder 10. One of the flaps 28 has a recess 30 located in the extension of the notch 23 to allow the passage of the braid 24.1-24.4 closest to the collector. Each cage 13.1-13.4 further comprises a system 31 for fixing to the plate 12. Each fixing system 31 is formed by two pairs of fixing lugs 32. The lugs 32 of each pair come from two opposite edges. screw edges 20, 21.

As can be seen in Figures 5 or 6, the upper wall 19, the two side walls 17 and 18 (and the flanges 20, 21 just for the 4645) form a cage body 39 in which the brush 15.1-15.4 slides. .

A tab 32 of each pair crosses the plate 12 right through the opening 33 made according to its thickness. The other tab 32 of each pair is in abutment against one side of the interior contour of square shape delimiting the orifice 14. The legs 32 of each pair are folded towards one another against the plate 12. Alternatively, the system fixing 31 comprises at least one rivet passing through the plate 12 and an end wall 20, 21 of the brush cage.

Furthermore, the spiral spring 35 associated with each cage 13.1-13.4 biases the brush 15.1-15.4 corresponding radially towards the contact blades of the collector carried by a body of the collector made of electrically insulating material, such as plastic. Each spring 35 is in this case mounted around a holding system 37 here formed by a pin extending axially relative to the axis X. This pin 37 called antenna is obtained by folding one of the walls of end 20 of each cage 13.1-13.4.

The cage 13.1-13.4 illustrated in Figure 7 differs from that illustrated in Figure 6, in that when looking from the X axis outward, the antenna 37 is disposed to the right of the two side walls and the upper wall forming the cage body 39 for housing the brush while for the cage

13.1-13.4 illustrated in FIG. 6 the antenna 37 is arranged to the left of the cage body 39.

This different arrangement may in particular be due to the direction of rotation of the collector 212. Indeed, when we look at the brush of the X axis towards the outside, it comprises two parts which are superimposed, namely a start part on which the rotating collector blades arrive first and an end portion from which the collector blades will detach which can cause an electric arc. In order to avoid this electric arc, it is expected that the end part has a higher electrical resistance than the start part. Thus, the starting part will be connected to the braid and the antenna 37 will be located on the other side.

There are thus defined two versions of cages called version 1 shown in Figure 6 and version 2 shown in Figure 7, these two versions being chosen according to the direction of rotation of the collector relative to the brushes.

For example, the version 2 cage is adapted for a clockwise rotation of the collector when looking in FIG. 1 from left to right along the X axis and the version 1 cage is adapted for an anti-clockwise rotation direction of the collector when looking in Figure 1 from left to right along the X axis.

The following describes, with reference to FIGS. 8 and 9, the activation of the starter fuse 2 in the event of overheating to ensure its protection. In normal operation, that is to say when the deformation temperature of the overmolded layers 122 has not yet been reached, the tabs 32 of the cages 13.1, 13.3 of positive polarity are isolated from the plate 12 while the spring 35 which is mounted compressed applies a force F1 against the brush 15.1, 15.3 so as to keep it constantly in contact with the blades of the collector. In reaction, the spring 35 also applies a force F2 to the cage 13.1, 13.3 via the antenna 37. The cages 13.1 and 13.3 cannot however move relative to the plate 12 due to the rigid nature of the assembly. When overheating occurs, for example caused by an idle operation of the starter for a long time, the deformation temperature of the insulating layers 122 is reached. The reaction force F2 exerted by the spring 35 on the antenna 37 then generates a pivoting of the cages of positive polarity 13.1 and 13.3 relative to the plate 12, so that at least one lug 32 of a cage 13.1, 13.3 comes into contact with the plate 121 connected to earth to establish a short circuit. This short circuit generates a considerable increase in the current flowing through the machine, which has the effect of blowing the fuse 2 of the starter causing the power to the engine to stop. This thus ensures protection of the starter while the current flowing through the machine during an idle operation of the engine causing overheating does not normally allow the fuse 2 to melt.

A fourth solution illustrated in FIG. 10 differs from the third solution in that, instead of the lug 32 of a cage 13.1, 13.3 which comes into contact with the plate 121 connected to ground to establish a short circuit. , it is the body 39 of the cage 13.1, 13.3 which comes into electrical contact with the cylinder head 7 under the effect of the spring which causes it to tilt. For example, the upper wall 19 or one of the side walls 17 or 18 comes into contact with the cylinder head 7.

However, there is a need to further increase the reliability of the third solution or the fourth solution.

Indeed, it is possible that the tilting of the cage cannot take place and that the short circuit continues without triggering the melting of the fuse. For example, if the spring breaks. This is particularly the case if the cage is broken and the current flows through the spring and the antenna to go from the positive brush to the plate 12. This causes the spring to collapse under the effect of the current.

OBJECT OF THE INVENTION

The object of the invention is to meet this need while remedying at least one of these aforementioned drawbacks.

According to the invention, a brush holder is provided for a motor vehicle starter, the brush holder being provided with an X axis and comprising:

-a support plate comprising:

- a metal plate having a first polarity,

- an electrically insulating fusing element on the metal plate;

-a broom cage mounted on the support plate, the cage comprising:

- a cage body,

-a fixing lug extending from the brush body, bearing on the melting element of the support plate,

a brush having a second polarity different from the first polarity, the brush being mounted in the body of the brush cage;

According to a general characteristic, the metal plate comprises at least one recess covered by the melting element and the fixing lug bears on the melting element of the support plate in the region of the recess.

When the temperature of the brush holder increases too much, an evacuation of the residues from the melting of the melting element is obtained, which allows a simpler tilting of the cage in order to obtain direct contact between the cage and an element having a other polarity. This contact can cause a fuse electrically connected upstream of the brushes to melt. This is advantageous because when the fuse is blown the risk that the starter catches fire is very low.

By making this recess, on the one hand, the molten plastic is removed, which facilitates the tilting of the cage. On the other hand, the breakage of the plate is favored so that the plate will break before the cage, which makes it possible to prevent all the current passing through the antenna and the spring. This would destroy the spring and stop the tilting.

According to other characteristics taken individually or in combination:

- The metal plate comprises a second recess, and the cage comprises a second fixing lug which bears against the melting element in the region of the second recess.

It also favors tilting using a second leg of the cage which is supported on the fusion element at a second recess.

- the two fixing lugs pass through the support plate.

- The melting element comprises a layer overmolded on the support plate which in the initial state keeps the cage in position relative to the support plate.

- the brush holder comprises a first spring capable of acting on the brush to make it slide in its cage body and the brush holder comprises, in addition to the spring known as the first spring, a second spring configured so that the cage rocks relative to the plate support under the action of the first spring and the second spring when the fusing element melts.

An even more reliable tilting of the brush cage is thus obtained. It can be provided that the brush holder is integrated into a starter comprising a cylinder head. In this case there is an arrangement of the cage on the plate so that the tilting can allow a short circuit between the cage and the cylinder head or between the cage and the support plate, this short circuit allowing a sufficient current flow to make blow the fuse electrically connected upstream with respect to the brushes, the current going from the brushes to the collector. This is advantageous because when the fuse is blown the risk that the starter catches fire is very low.

the fixing lug has a section and the brush holder comprises a central orifice centered on the axis X so that the support plate comprises between the recess and the central orifice a resistance portion whose section is smaller than that of the bracket.

This allows, when a short circuit is present, destruction of the part of the metal plate supporting the fixing lugs before that of the cage.

The invention also relates to a starter comprising a brush holder as described above and a fuse element electrically connected upstream of the brush and the resistance portion is configured so that its section is smaller than that of the fuse element.

It is thus possible during the presence of a short circuit, a tilting of the cage allowing itself a short circuit causing the melting of the fusible element.

BRIEF DESCRIPTION OF THE FIGURES

Other characteristics and advantages of the invention will appear on examining the detailed description of modes of implementation and embodiments, in no way limiting, and the appended drawings in which:

FIG. 1, already described, represents a section of a starter according to the state of the art;

FIG. 2, already described, represents a view of the principle of operation of the electric motor of the starter according to the state of the art;

FIGS. 3, already described, represents a view of a brush holder according to the state of the art;

FIG. 4 and 5 already described, respectively represent a view of a plate according to the state of the art;

FIGS. 6 and 7 already described, each represent a certain type of starter depending on whether the manifold 212 rotates counterclockwise or clockwise with respect to the brushes according to the state of the art;

FIG. 8, 9 and 10, already described, show the principle of the tilting of a brush cage according to the state of the art;

FIG. 11 illustrates a brush holder according to the invention;

FIGS. 12 and 13 illustrate a support plate according to the invention;

FIG. 14 illustrates in section a brush cage mounted on a support plate according to the state of the art;

FIG. 15 illustrates in section a brush cage mounted on a support plate according to the invention; and

FIG. 16 illustrates a brush holder according to another embodiment of the invention.

Identical, similar, or analogous elements keep the same reference from one figure to another.

DESCRIPTION OF EXAMPLES OF EMBODIMENT OF THE INVENTION

FIG. 11 illustrates a brush holder according to the invention. This brush holder 10 can be included in the starter 201 in place of the brush holder of the prior art.

This brush holder 10 is provided with an X axis and comprises:

a support plate 12 comprising a metal plate 121 having a first polarity and a fusing element 122 electrically insulating on the metal plate 121;

-four brush cages 13.1, 13.2, 13.3, 13.4 mounted on the support plate 12, each of the cages comprising:

a cage body 39 for receiving a corresponding brush 15.1, 15.2, 15.3, 15.4,

at least one fixing lug 32 bearing on the melting element 122 of the support plate 12.

It can be provided that the two brushes 15.1 and 15.3 for the cages 13.1 and 13.3 have a second polarity different from the first polarity.

Figures 12 and 13 illustrate a support plate 12 comprising the metal plate 121. The support plate also includes overmolded layers 122 forming the fusing element. Provision may be made for the fusing element to comprise two overmolded layers 122 on the metal plate

121 of the support plate 12, each of the layers being arranged on a face of metal plate 121.

For example, the overmolded layers 122 at least partially protect the brush support face as well as the opposite face. Overmolded layers

122 cover all the risk zones of the metal plate 121, that is to say, all the zones where a short circuit could appear.

It can be seen in FIG. 12 that the fixing lugs 32 pass through the support plate 12. For this purpose, as can be seen in FIG. 13, openings 33 are provided for two four fixing lugs 32 for each brush cage 13.1-13.4 while the other two fixing lugs 32 are received in the orifice 14.

In addition, the metal plate 121 comprises at least one recess 43 covered by the fusing element 122, one of the fixing lugs 32 being supported on the fusing element 122 of the support plate 12 in the region of the recess 43.

Provision may be made for the metal plate 121 to include a second recess 43, and for the cage to include a second fixing lug 32 which bears against the fusing element 122 in the region of the second recess 43.

The overmolded layers 122 on the support plate 12 allow the initial state to keep the cage 13.1-13.4 in position relative to the support plate 12.

The fixing lug 32 has a section and a resistance portion 64 whose cross section is smaller than that of the fixing lug 32 is defined between the central orifice 14 centered on the axis X and the recess.

In addition, when the brush holder is included in the starter 201 comprising the fuse 2 electrically connected upstream of the brushes 15.1,

15.2, 15.3, 15.4 and the resistance portion 64 is configured so that its section is smaller than that of the fuse element.

Figure 14 illustrates in section a broom cage mounted on a support plate according to the state of the art.

We can see the fixing lugs 32 of the broom cage which are supported on the metal plate 121 through the melting element in this case, the layers 122 overmolded.

Thus, when the fusing element 122 is not melted, the cage 13.1 is mounted by means of the fixing lugs 32 on the plate 12. For this, for example, the fixing lugs pass through openings 33 arranged in the plate as in the state of the art (cf. FIGS. 4 and 5) and are supported on the metal plate 121 by means of the fusing element 122. This support compensates for the force F2 of the spring 35 visible on Figure 9 exerted through the antenna on the cage 13.1.

FIG. 15 illustrates in section a brush cage 13.1 mounted on a support plate according to the invention. Compared to the state of the art, we can see the recess 43 on which we see one of the fixing lugs in support.

When the melting element is not melted, the cage 13.1 is mounted by means of the fixing lugs 32 on the plate 12, one of which is supported by means of the melting element 122 on the recess 43 This support compensates for the force F2 of the spring 35 visible in FIG. 9 exerted via the antenna on the cage 13.1.

When the fusion element melts, the support of the fixing lugs 32 on the metal plate 121 via the fusion element 122 is not stable so that the support no longer compensates for the force F2 which prevails and causes the broom cage to tip over. Due to the recess, when the melting element is melted, the molten results can be evacuated and do not obstruct the tilting of the broom cage which is thereby facilitated.

FIG. 16 illustrates a brush holder according to another embodiment of the invention.

This other embodiment differs from what has been described previously in that it is provided in addition to the recess 43 of the support plate 12 comprising the metal plate 121 and a fusing element

122, which the brush holder 10 comprises for the cage 13.1 in addition to the first spring 35 capable of acting on the brush 15.1, to make it slide in its cage body 39, a second spring 40 configured so that the cage 13.1 rocks relative to the support plate 12 under the action of the first spring 35 and the second spring 40 when the fusing element 122 melts. This makes tilting even easier.

As can be seen in FIG. 16, this is for example a spring of the C-spring type. However, it is also possible to provide a spring of the O-spring type. This second spring 40 comprises two ends, a first end exerting a first force on the body 39 of the first brush cage 13.1, and a second end exerting a second force on the body 39 of the second brush cage 13.3.

For example, this second spring exerts forces directly on the body 39 of the brush cage 13.1 and 13.3. For example, in the radial direction in the direction from the center towards the external periphery of the support plate 12.

For this, the two cage body 39 with brush 13.1 and 13.3 on which the forces of the second spring are exerted each comprise a groove 41 for receiving the second spring 40, the two grooves facing the axis X and being arranged on the outer periphery of their respective cage body 39.

Claims (7)

1. Brush holder (10) for a motor vehicle starter (201), the brush holder (10) being provided with an X axis and comprising: a support plate (12) comprising: - a metal plate (121) having a first polarity, - an electrically insulating fusing element (122) on the metal plate (121); -a brush cage (13.1, 13.2, 13.3, 13.4) mounted on the support plate (12), the cage comprising: - a cage body (39), a fixing lug (32) extending from the brush body, bearing on the melting element (122) of the support plate (12), a brush (15.1, 15.2, 15.3, 15.4) having a second polarity different from the first polarity, the brush being mounted in the body of the brush cage; characterized in that the metal plate (121) comprises at least one recess (43) covered by the fusing element (122) and in that the fixing lug (32) is supported on the fusing element (122 ) of the support plate (12) in the region of the recess (43). 2. Brush holder (10) for a starter (201) of a motor vehicle according to the preceding claim, characterized in that the metal plate (121) comprises a second recess (43), and in this the cage comprises a second fixing lug ( 32) which bears against the melting element (122) in the region of the second recess (43). 3. Brush holder (10) for a motor vehicle starter (201) according to the preceding claim, characterized in that the two fixing lugs (32) pass through the support plate (12). 4. Brush holder (10) for a motor vehicle starter (201) according to one of the preceding claims, characterized in that the fusing element (122) comprises a layer overmolded on the support plate (12) which at the he initial state keeps the cage (13.1-13.4) in position relative to the support plate (12). 5. Brush holder (10) for a starter motor (201) according to one of the preceding claims, characterized in that the brush holder (10) comprises a first spring (35) capable of acting on the brush (15.1, 15.2 , 15.3, 15.4) to make it slide in its cage body (39) and in that the brush holder (10) comprises, in addition to the spring (35) said first spring, a second spring (40) configured so that the cage (13.1- 13.4) rocking relative to the support plate (12) under the action of the first spring (35) and the second spring (40) when the melting element (122) melts. 6. Brush holder (10) for a starter motor (201) according to one of the preceding claims, characterized in that the fixing lug (32) has a section and in that the brush holder (10) comprises a central orifice (14) centered on the X axis so that the support plate (12) comprises between the recess and the central orifice (14) a resistance portion (64) whose cross section is smaller than that of the tab fixing (32). 7. Starter (201) comprising a brush holder (10) according to the preceding claim characterized in that it comprises a fuse element electrically connected upstream of the brush (15.1, 15.2, 15.3, 15.4) and in that the resistance portion is configured so that its section is smaller than that of the fuse element.