EP2286492B1 - Brush holder device, and use thereof for producing a motor vehicle starter - Google Patents

Description

The present invention relates to the field of starters for a motor vehicle. The invention relates to a brush holder device.

Conventionally, a motor starter brush holder is mounted on the starter rotor shaft so as to cooperate with an electrical collector integral with the rotor shaft.

In the brush holder devices for a vehicle starter, it is known to increase the number of brushes for high power starters, in order to reduce the electrical contact resistance or to limit the individual wear of the brushes and thus prolong the duration starter life. Usually, the brushes, generally even in number, are housed in respective brush holders which are arranged on a brush support plate of the brush holder device. With the increase in the number of brushes, there then arises the problem of the electrical connections of these brushes respectively, on the one hand, to the rotor supply circuit (for brushes of positive polarity for example), and, on the other hand on the other hand, to the vehicle ground (for brushes of negative polarity, for example). Indeed, the space devoted to these elements being reduced to a minimum, it is important first of all that the electrical insulation, between them, brushes of different polarities is optimal, as well as the electrical insulation of each of the brushes with its environment, so as to avoid the risks of short-circuiting and untimely generation of arcing. This point is even more important that such brushes are often, typically for reasons of wear distribution, arranged on the brush support plate alternating their polarities. It is also important that the electrical connection of each of the brushes allows the passage of currents possibly high, as well to improve the starter performance as to reduce the heating and increase the service life. Braids, cords or rings or sectors of copper rings are generally used to make these connections.

Conventionally, the brushes are each placed in a brush holder fixed on one side of the brush support plate, and the central portion of the latter comprises an orifice through which the assembly formed by this plate, brush holders and brushes is mounted around the starter rotor shaft. By convention, the following will be referred to in the following as the front face of the brush support plate on which the brush holders are fixed, and the rear face of the opposite face of this plate. In some cases, the support plate of brooms, conventionally a disc, has a set of through holes and has, on its rear face, a housing for receiving a braid, a ring or a sector of copper ring to which the brushes are individually electrically connected and which electrically interconnects all or part of the brushes of the same polarity. One or more inter-brush electric bridges are thus produced, which simplifies the connection of the brushes thus electrically connected to each other with the corresponding electrical circuit. Such an arrangement however results in a certain complexity in the production of the support plate of brushes, which increases the cost. It also induces additional space in the rear face of this plate, which may be incompatible with specific constraints of space in the space allocated to the starter, which is increasingly reduced on motor vehicles.

WO 02/50981 A1 describes the features of the preamble of claim 1.

The object of the invention is to propose a device making it possible to set up such inter-brush bridges in a simple, inexpensive and applicable manner regardless of the configuration of the starter and the brush support plate in order to achieve a standardization generating additional savings in the manufacture of brush holders.

The invention relates to a brush holder device for a motor vehicle starter comprising a plate supporting a set of brush holders. According to the invention, each of the brush holders accommodates, at its outer end opposite its end, through which a broom which it receives is placed in electrical contact with a collector, a tip made of a dielectric material and comprising means for maintaining a conductive element for electrically connecting the blade with at least one separate brush, of similar polarity, received in a similar brush holder fixed remote on the plate.

This tip fulfills a shutter function of one end of the corresponding brush holder which is fixed on a support plate brushes.

The holding means are advantageously arranged in such a way that the inter-brush bridge is on the same side of the brush support plate as that on which the brush holders are fixed, that is to say, to use the denomination mentioned above, on the side of the front of this deck. In addition, these holding means are advantageously configured, according to the invention, to hold the inter-brush bridge at least in its part closest to the outer edge of the brush support plate.

By convention, the term "lower" will be used hereinafter to denote the portion of the inter-brush bridge closest to the support plate of brushes and brushes, and "superior" to that part of this bridge furthest from said platen and said brushes. Similarly, for the sake of clarity, the invention will be described in the following in one of its preferred embodiments, but not limiting, in which the brush support plate is conventionally in the form of a disk.

It should be noted that, particularly in this case, the inter-brush bridge may be in the form of a ring, a ring sector, or a set of ring sectors of a material driver (by example of copper) electrically interconnecting all the brushes of the same polarity or only a part of them. More generally, the inter-brush bridge may be in the form of a continuous conductive element interconnecting all the brushes of the same polarity, or a set of elementary sectors electrically connecting together all or part of the brushes of the same polarity.

According to one of its features, the tip is made of a dielectric material, for example a polymeric material.

According to a complementary feature, the end closed by the tip is the end of the receiving housing of the brush in the brush holder opposite to the end of the same housing by which the blade can come into contact with a manifold. More specifically, the tip seals the end of the brush receiving housing closest to a protective housing, or cylinder head, surrounding the assembly consisting of the support plate brushes, brush holders and brushes. Thus, for example, when the brush support plate is in the form of a disk whose central portion is pierced with an orifice to allow passage of a starter rotor shaft, the different brush holders are arranged radially. on this disc, and the tip closes the end located on the outer side thereof, periphery of the assembly.

The tip then performs an additional function of electrical insulation between the different brushes and their environment, specifically between the different brushes and the aforementioned protective housing. To this function is also added a function of mechanical isolation between the brush and the protective casing, the tip preventing, by its presence, any dust from the wear of the brush to come into contact with the housing that they could then pollute or on which they could constitute sites of initiation of possible electric arcs.

According to another characteristic, the holding means that comprises the endpiece comprise at least one tongue that isolates electrically and mechanically while holding the inter-brush bridge element inserted into this endpiece. More specifically, the tip comprises a portion substantially forming a U, a branch of which is formed by this isolation tab.

According to another of the features of the invention, another of the branches of this U carries out the electrical isolation between the inter-brush bridge and a protective casing of the assembly formed by the support plate of brushes, the brush holders and the brushes, or, more generally, between the inter-brush bridge and the external environment of the brush holder and its support plate.

According to different variants of embodiment in the implementation of the invention, the branches of this U can be configured in such a way that, when the end piece is put in place at the end of a brush holder and when the Brush support plate is placed around a rotor shaft, they are located in a plane substantially perpendicular to the axis of this shaft or in a plane substantially parallel thereto.

• une fonction d'isolation électrique et mécanique des balais et porte-balais vis-à-vis d'un carter de protection de l'ensemble formé par la platine support de balais, les porte-balais et les balais,
• une fonction d'isolation électrique et mécanique des porte-balais vis-à-vis du pont inter-balais, chacun des balais de même polarité étant relié électriquement au pont inter-balais par des moyens appropriés tels que des tresses de fils conducteurs, par exemple,
• une fonction mécanique de maintien de ce pont inter-balais.

The tip of the brush holder device according to the invention as it has just been defined in its principle thus fulfills:

• a function of electrical and mechanical isolation of the brushes and brush holders vis-à-vis a protective housing of the assembly formed by the support plate brushes, brush holders and brushes,
• a function of electrical and mechanical insulation of the brush holders vis-à-vis the inter-brush bridge, each of the same polarity brushes being electrically connected to the inter-brush bridge by appropriate means such as braids son son, by example,
• a mechanical function for maintaining this inter-brush bridge.

The tip of the brush holder device according to the invention is particularly suitable for the equipment brush holder very simple shapes, such as for example made by folding thin sheets, which allows significant cost reductions compared to brush holders made by molding plastics.

Since the brushes have shapes and sizes that can be selected from one motor vehicle starter model to another, and the same applies to the brush holders, it follows that the nozzle of the device according to the invention can be realized in the form of a standard model used profitably on different types of motor vehicle starter. In preferred embodiments, the inter-brush bridge holding function is performed by a part of the tip different from that which is at the end of the brush holder and which ensures the electrical insulation of the brushes with regard to their environment. Since the shapes making it possible to ensure these different functions are thus distinct in each endpiece, the invention therefore makes it possible to reduce the variants of embodiments of the brush holder assemblies. This allows a further reduction in costs by standardizing the manufacture of assemblies receiving brushes and inter-brush bridges. In addition, made in a dielectric material and ensuring, as previously indicated, an electrical insulation function, the tip of the device according to the invention allows the manufacture of the brush holder and that of the support plate brushes in any material, for example folded sheet, which leads to a further reduction in cost.

• les figures 1 A et 1 B sont des vues schématiques en perspective de premier et second modes de réalisation d'un dispositif porte-balais selon l'invention formé chacun d'une platine support de balais sur laquelle sont fixés six porte-balais munis chacun d'un embout.
• la figure 2 est une vue schématique en perspective d'un premier mode de réalisation d'un embout inclus dans un dispositif porte-balais selon le premier mode de réalisation, et
• la figure 3 est une vue schématique en perspective d'un second mode de réalisation d'un embout inclus dans un dispositif porte-balais selon le second mode de réalisation.

Other characteristics and advantages of the invention will emerge on reading the description which follows, illustrated by the following figures in which:

• the Figures 1A and 1B are schematic perspective views of first and second embodiments of a brush holder device according to the invention each formed of a support plate brushes on which are fixed six brush holders each provided with a tip.
• the figure 2 is a schematic perspective view of a first embodiment of a tip included in a brush holder device according to the first embodiment, and
• the figure 3 is a schematic perspective view of a second embodiment of a tip included in a brush holder device according to the second embodiment.

The Figures 1A and 1B present the brush holder device according to first and second embodiments, respectively.

As shown in FIGS. 1A, 1B, the brush holder is shown mounted on a manifold 7 of the starter. The manifold 7 is provided to be fixedly mounted on a rotor shaft (not shown) of the starter. The rotor shaft is normally engaged in a through hole 2 shown in FIGS. Figures 1A , 1 B .

The brush holder device comprises a brush support plate 1 made in the form of a disk drilled at its center at the through orifice 2. The plate 1 supports six brushes each inserted in a suitable housing provided in a holder. 3. Brushes and brush holders are regularly distributed radially on the plate 1, and each of the brush holder 3 is open at its end closest to the orifice 2 to allow the electrical contact of the broom it accommodates. with the starter manifold.

For the sake of cost reduction, each of the brush holders is made by folding a plate of thin sheet so as to form substantially an omega whose end branches are fixed on the plate 1. Such an embodiment brings an additional advantage in that such a brush holder has a greater resistance to high temperatures, which is particularly advantageous especially for starters called to be frequently solicited during operation of the vehicle.

On the Figures 1A and 1B it is also partially shown a protective housing or yoke 4 surrounding the brush holder device comprising the brush support plate 1, the brush holder 3 and the brushes.

In the examples illustrated by the Figures 1A and 1B , an inter-brushing electrical bridge 5 interconnects all the brushes placed on the brush support plate 1. This inter-brush bridge, which is made of a material having a high electrical conductivity (preferably, but not exclusively, of copper), here takes the form of a rigid ring of a height of the order of a few millimeters electrically interconnecting all the brushes. It should however be noted that such an inter-brush bridge can take any form and electrically connect together all or part of the brushes placed on the plate 1.

According to the particular embodiments illustrated by the Figures 1A and 1B , the ring forming the inter-brush bridge 5 is deformed in two diametrically opposed zones (marks 50 on the Figures 1A and 1B ). These deformations are advantageously placed opposite two diametrically opposite orifices, designated by the marks 100 on the figure 1 . These orifices are formed in the support plate brush 1 to allow the passage of tie rods (not shown in the figures) which are used for mechanical assembly of the starter.

A tip, designated by the reference numeral 6, closes one of the ends of each of the brush holders 3. More specifically, the tip 6 closes the peripheral end of the receiving housing of the blade in the brush holder, that is to say the one that is furthest from the through-orifice 2 through which the plate 1 allows passage of the starter rotor shaft. It thus constitutes a mechanical separation between the blade placed in the brush holder 3 and the protective casing 4. More generally, it mechanically separates the blade from its external environment at its end opposite the end intended to come into electrical contact with the blade. the starter manifold. The tip 6 is preferably made of a dielectric material. It isolates well Also electrically the brush, including the protective casing 4. In an effort to reduce cost, it is for example made by injection / molding a plastic material for example based on polyamide.

Two embodiments of the tip corresponding to the first and second embodiments of the brush holder device according to the invention are represented in detail by the figures 3 and 4, respectively.

In general, as shown in Figures 2 and 3 , a tip comprises a body 60 forming a housing 61 whose shape and dimensions are substantially identical to the shapes and dimensions of the cross section of the brush holder 3 at its end to which the tip is placed, so that the body 60 can simply be nested around this end. A channel 62 extends inside the housing 61, in the same direction as the edges 610 of the latter, over a length of a few millimeters. When the tip 6 is put in place at the end of the brush holder 3, this channel accommodates a portion of a spring (not shown in the figures) placed at the rear of the broom spring to ensure, by its compression by the brush, maintaining the electrical contact between the latter and the starter manifold. At its base 63, the body 60 of the tip 6 is substantially planar so as to bear on the front face of the brush support plate 1, on which the brush holders 3 are fixed.

One or the other of the first and second embodiments of the invention corresponding to the Figures 1A , 2 and 1 B , 3 is chosen according to the intended starter application. According to the embodiment chosen, the shape of the tip 6 at the end of the body 60 opposite its base 63, and the shape of the inter-brush bridge 5 are different, as is clear from the figures.

Regarding the tip 6, it comprises, at the end of the body 60 opposite its base 63, a substantially forming a portion U which is oriented differently depending on whether it is the first or the second embodiment. The branches of this U form the holding means mentioned above intended to retain all or part of the inter-brush bridge 5.

According to the embodiment presented by the f igures 1 A and 2 , the branches of this U extend substantially parallel to the body 60 of the tip 6. In other words, once the tip 6 placed at the end of the brush holder 3 fixed to the plate 1 and the brush holder mounted in the starter, the legs of the U are disposed substantially perpendicular to the starter rotor shaft. In other words again, according to the embodiment more specifically illustrated by the Figures 1A and 2 once the tip 6 has been put in place at the end of the brush holder 3 fixed on the plate 1 and the brush holder device mounted in the starter, the branches of this U are arranged substantially perpendicularly to the axis of the blade. through hole 2.

According to the second embodiment more specifically illustrated by the figure 3 , the tip 6 is configured such that the legs of this U then extend substantially parallel to the axis of the through hole 2 when the tip 6 is placed at the end of the brush holder 3 fixed on the plate 1 and that the brush holder device is mounted in the starter.

Whatever the embodiment chosen, the inter-brush bridge 5 or the inter-brush bridge element is inserted into the groove formed by the U-shaped part of the tip 6. The branches of this U form a tongue, respectively. 64 and a tongue 65 extending from the body 60 of the tip 6 substantially over the entire width thereof, tabs which are interconnected by a tongue 66 of the same width which constitutes the bottom of the U. The bridge inter-brush, which is here in the form of a flat conductive ring, is thus maintained on at least three sides of its periphery, including at least, whatever the variant chosen, its nearest part of the outer edge of the plate 1 and its lower part. This allows both to ensure a correct and reliable maintenance over time of the inter-brush bridge, and to fulfill a guiding function during the establishment thereof.

Indeed, according to the embodiment illustrated by the figures 1 A and 2, more specifically adapted to the case where the inter-brush bridge is in the form of a ring or flat ring portions whose dimension in the longitudinal direction of the collector is greater than its dimension in the transverse direction of this collector, it is sufficient, once the tips placed at the ends of each of the brush holder 3, to bring the inter-brush bridge in the upper part of the front face of the assembly formed by the plate 1, the brush holders 3 and the brushes and insert substantially parallel to the axis of the orifice 2 between the two tongues 64 and 65, which then constitute in its regard cooperating jaws.

Advantageously, the space separating the tabs 64 and 65, occupied by the bottom 66, is very slightly less than the thickness of the ring or the ring portions forming the inter-brush bridge, so that the elasticity natural material constituting the tip 6 allows a slight compression of this bridge on the three sides of its periphery by which it is in contact with the tip 6, thereby contributing to its maintenance while allowing a very simple implementation and fast.

According to the embodiment illustrated by the Figures 1 B and 3 , more specifically adapted to the case where the inter-brush bridge is in the form of a ring or a set of flat ring sectors whose transverse dimension is greater than the longitudinal dimension, the inter-brush bridge 5 is advantageously inserted substantially perpendicularly to the axis of the orifice 2 (thus radially) between the tongues 64 and 65. In this case, for easy placement, it will be advantageous to put in place only part of the tips 6 on the brush holder 3, then to insert the inter-brush bridge, and finally to put in place the remaining bits to put said bridge in slight compression at its outer periphery to contribute to a more reliable maintenance.

It follows from the foregoing that whatever the configuration of the inter-brush bridge 5 and the tip 6, the latter ensures, by the tabs 64 and 65 that it comprises, a reliable and durable maintenance of said bridge-inter brooms and a quick and easy installation of it. The tabs 64 and 65, as well as the bottom 66 of the U-shaped part of the endpiece, also fulfill the functions of mechanical isolation and electrical insulation for the inter-brush bridge 5 with respect to, respectively, the carriers. brushes 3 and brushes housed therein and the protective casing or cylinder head 4. More generally, the nozzle thus makes, by the U-shaped portion that it comprises, a mechanical and electrical insulation of the inter-brush bridge 5 with regard to the whole of its environment. The electrical connection between each brush and this bridge is achieved by means of, for example, conductive braids (not shown).

The tip also ensures, by its body 60, a mechanical and electrical insulation of the brush holder which it is associated with and the broom that it receives with regard to their external environment, and in particular, with regard to a protection casing 4.

A tip such as the tip 6 can be used to close the end of a brush holder even in the absence of inter-brush bridge, the height of the tongues 64 and 65 and the bottom 66 being, whatever the chosen variant, low (typically of the order of a few millimeters), and the shape 60 of the body of the tip 6 by which the latter is fitted on the end of the brush holder being independent of the shapes of the tongues 64 and 65 and from the bottom 66.

It follows that the tip can be used for any type of platinum brush holder and for any type of starter, which allows to reduce the costs by increasing the quantities of the makes the standardization and versatility of the starter production chains.

Similarly, such a tip allows the realization of very simple brush support plates, for example by stamping thin sheet metal plates on which are then fixed the folded sheet plates forming the brush holder, thus allowing additional savings.

It appears however that the invention can not be limited to the embodiments illustrated by the figures and described above, and that it extends to all equivalent forms and all technically operating combinations thereof.

In particular, the shapes and dimensions of the inter-brush bridge 5 are not limited to the shapes and dimensions explained above. The shapes and dimensions defined by the tabs of the U-shaped portion of the endpiece being directly connected, as described above, to the shapes and dimensions of this inter-brush bridge, it follows that the U-shape and the dimensions of this part are not, either, exclusive, and that the invention also extends to any shape to simply maintain, at least in its closest part of the outer edge of the support plate brushes for a reliable and durable maintenance, all or part of an inter-brush electric bridge.

Claims (7)

1. Brush holder device for a motor vehicle starter, comprising a plate supporting an assembly of brush holders, characterized in that each of said brush holders receives, in its outer end which is the opposite end to its end by which a brush which it receives is brought into electrical contact with a commutator, an end piece (6) made of a dielectric material and comprising means for holding a conductive element (5) designed to electrically connect said brush with at least one separate brush having a similar polarity and housed in an analogous brush holder attached at a distance therefrom on said plate.
2. Device according to Claim 1, characterized in that said holding means of said end piece are configured so as to hold said conductive element on the same side of a plate supporting said brush holders as that on which said brush holders are placed on said plate.
3. Device according to either one of Claims 1 and 2, characterized in that said end piece is made of a dielectric material and in that it comprises a body (60) which closes off a housing for receiving a brush in a brush holder in the end of the latter which is the opposite end to the end by which said brush received in said brush holder is brought into electrical contact with a commutator of the starter.
4. Device according to any one of Claims 1 to 3, characterized in that said end piece comprises a U-shaped part, one branch (64) of which isolates both electrically and mechanically the brush holder fitted therewith from said conductive element (5), and one branch (65, 66) of which isolates both electrically and mechanically a brush received in said brush holder with respect to a protective casing or yoke (4) which is seated around the assembly formed by the brush support plate, the brush holders and the brushes of the starter.
5. Device according to Claim 4, characterized in that said U-shaped part of said end piece extends substantially parallel to said body (60) of said end piece.
6. End piece according to Claim 4, characterized in that said U-shaped part of said end piece extends substantially perpendicular to said body (60) of said end piece.
7. Brush holder device according to any one of Claims 1 to 6, characterized in that each of said brush holders is produced in the shape of an omega obtained by bending a thin metal sheet.

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