DE112006002126T5 - Brush and electric lathe equipped with such a brush - Google Patents

Abstract

Brush (34) adapted to interact with a collector of a rotary electric machine of the type comprising:
A proximal end portion whose body is of generally rectangular parallelepiped shape is radially bounded by a proximal axial cylindrical concave surface (70) of generally axial orientation (A) adapted to interact with the cylindrical convex external surface of a collector of the electric lathe and transversely bounded by two lateral upstream and downstream opposing surfaces (68a, 68b) of generally axial alignment;
- means (74a, 74b) for guiding the brush (34) radially slidable in complementary means (38) of a brush support (30, 32) of the machine, the guide means defining an axial center reference plane (PM) of the brush,
characterized in that the upstream lateral surface (68a) and the downstream lateral surface (68b) are not symmetrical with respect to the reference plane (PM).

Description

The The present invention relates to a brush or a contact, suitable for interaction with a collector or collector of a electric lathe or an electric rotary motor.

The The invention is particularly directed to an electric motor as used for the equipment of motor vehicles, such. B. an electrical Drive motor for a windshield wiper mechanism.

An electric lathe, z. Of the type described and reproduced in the document FR-A-2797110 in particular comprises an axial end flange in the general form of a badge which extends in a radial plane perpendicular to the axis of rotation of the rotor of the machine, at one axial end of which is arranged a collector or collector extending through a central opening of the machine Flange extends.

The flange carries different elements and electrical components and in particular at least two contact portions or brushes, each extending along a radial direction to interact with the collector or collector, each brush having conductive traces carried by the collector , forms an electrical commutator (as described and illustrated in the document DE-A-19 521 376 ).

• – einen proximalen Endabschnitt, dessen Körper von generell rechteckigparallelepiped-förmiger Gestalt ist, radial begrenzt wird durch eine axiale proximale konka ve zylindrische Fläche von generell axialer Ausrichtung, geeignet zur Wechselwirkung mit der zylindrischen konvexen Endfläche eines Kollektors einer elektrischen Rotations- oder Drehmaschine bzw. -vorrichtung und transversalwärts und begrenzt ist durch zwei Lateralflächen, flussaufwärts liegend und flussabwärts liegend, gegenüberstehend ausgerichtet bei generell axialer und radialer Ausrichtung;
• – Bürstenführungsmittel, radial gleitfähig, in komplementären Mitteln einer Maschinenbürstenstütze, wobei die Führungsmittel eine axiale Mittelebene der Bürste definieren, die Referenzebene genannt wird.

In the document FR-A-2797110 is any brush capable of interacting with the collector, of the type comprising:

• A proximal end portion whose body is of generally rectangular parallelopiped shape is radially bounded by an axial proximal concave cylindrical surface of generally axial alignment suitable for interacting with the cylindrical convex end surface of a collector of a rotary or rotary electric machine; and transverse and bounded by two lateral surfaces, upstream and downstream, oppositely oriented in generally axial and radial directions;
• - Brush guide means, radially slidably, in complementary means of a machine brush support, wherein the guide means defining an axial center plane of the brush, the reference plane is called.

In In this document each brush becomes radially slidable guided in an insulating part in the form of the housing.

According to another conception, which is described and illustrated in the document FR-A-2603141 For example, each brush comprises two parallel and opposing grooves or grooves extending in one and the same radial plane, the axial end flange of generally plate-like shape comprising receptacles bounded by pairs of parallel edges forming ribs received oppositely in the opposing gaps a brush.

Consequently In both designs, each brush slides radially or radially slidably guided, wherein a global Symmetrical conception exists with respect to its axial median Reference plane, the latter through the axis of rotation of the collector the rotor runs.

each Brush, also called coal or pole brush can be electrically connected or switched with respect to an electrical circuit of the engine.

The Brushes or coals are especially provided in pairs and are z. In a number of four in the form of two pairs provided on diametrically opposed brushes or contacts.

Of the axial end flange is z. As a metallic plate or badge, connected to the negative ground pole at which different Components or components are attached, which is the coal carrier plate or the brush holder plate.

you thus has z. B. via an electric motor or an electric motor with two pairs of magnetic poles and one Collector with four brushes or coals.

In such an engine causes the even number to the number Poland and coal and the general symmetry of the whole arrangement Commutation or switching phenomena simultaneously occur between the brushes and the slopes or conductive Traces of the collector, creating one or more electromagnetic Coupling phenomena may occur.

In order to improve the performance of such a rotary electric machine or rotary device, and in particular with respect to protection against electromagnetic interference, the present invention aims to cause an offset in the commutation or switching time of the different brushes with the conductive tracks or slopes of the collector or collector, and without this would change the general conception of the brush holder plaque, nor the conception of the collector but rather, by proposing a novel conception of the brushes.

Under this objective proposes the present invention Brush for the aforementioned type, which thereby characterized in that the laterally upstream surface and the laterally downstream surface Considering an arbitrary direction of rotation of the collector with Regarding the brush is not symmetrical with respect to the Reference plane or reference planes are.

• – die zwei flussaufwärts liegenden und flussabwärts liegenden Lateralflächen sind parallele ebene Flächen;
• – die zwei flussaufwärts liegenden und flussabwärts liegenden Lateralflächen sind parallel zur Referenzebene;
• – die zwei flussaufwärts liegenden und flussabwärts liegenden Lateralflächen sind mit Bezug auf die Referenzebene geneigt;
• – die flussaufwärts liegende Lateralfläche ist eine zylindrisch konkav oder konvex gekrümmte Fläche bezüglich der radialen Achse;
• – die flussabwärts liegende Lateralfläche ist eine zylindrisch gekrümmte konvexe oder konkave Fläche bezüglich der radialen Achse.

According to further characteristics of the brush or contact point or coal, one or the other of the following features applies:

• The two upstream and downstream lateral surfaces are parallel planar surfaces;
• The two upstream and downstream lateral surfaces are parallel to the reference plane;
• The two upstream and downstream lateral surfaces are inclined with respect to the reference plane;
• The upstream lateral surface is a cylindrically concave or convexly curved surface with respect to the radial axis;
• The downstream lateral surface is a cylindrically curved convex or concave surface with respect to the radial axis.

According to a further conception of the present invention the brush or pad or coal is characterized by that the two lying upstream and downstream located lateral surfaces are generally inclined with respect to the reference level.

• – die zwei flussaufwärts liegenden und flussabwärts liegenden Lateralflächen sind parallele Flächen;
• – die zwei flussaufwärts und flussabwärts befindlichen Lateralflächen sind zwei ebene Flächen.

According to further features of this brush:

• The two upstream and downstream lateral surfaces are parallel surfaces;
• The two upstream and downstream lateral surfaces are two flat surfaces.

• – der proximale Abschnitt umfasst eine leitfähige zentrale Säule von radialer Ausrichtung sowie eine Umhüllung, die lateralwärts die zentrale Säule umgibt, und die in einem distinkten oder unterschiedlichen Material bezüglich der zentralen oder mittleren Säule oder Kolonne ausgebildet ist;
• – die leitende oder leitfähige mittlere Säule oder Kolonne ist transversalwärts mit Bezug auf die Referenzebene zentriert;
• – die Führungsmittel sind gebildet mittels zweier radialer flussaufwärts befindlicher und flussabwärts befindlicher Rillen, die sich in ein und derselben radialen Ebene befinden und von denen jede zumindest in dem proximalen Endabschnitt ausgebildet ist;
• – die flussaufwärts liegend und flussabwärts liegend befindlichen Lateralflächen erstrecken sich axialwärts flussabwärts liegend oberhalb der Ebene der Führungsrillen bzw. über diese Ebene hinaus;
• – der proximale Endabschnitt umfasst einen inneren Absatz, der sich axialwärts unterhalb der Ebene der Führungsrinnen oder -rillen erstreckt, von generell rechteckig parallelepiped-förmiger Gestalt und radialwärts begrenzt durch eine axiale oder proximale Fläche, geeignet zur Wechselwirkung mit der zylindrischen konvexen externen Fläche des Kollektors und die transversalwärts begrenzt ist durch zwei flussaufwärts liegend befindliche und flussabwärts liegend befindliche Lateralflächen, einander gegenüberstehend, von generell axialer Ausrichtung;
• – die Lateralfacette, die flussaufwärts befindlich ist und die lateral flussabwärts liegend befindliche Facette des Absatzes sind nicht symmetrisch mit Bezug auf die Referenzebene;
• – die flussaufwärts liegende Lateralfacette bzw. die flussabwärts liegend befindliche Lateralfacette des Absatzes ist transversalwärts versetzt mit Bezug auf die lateral flussaufwärts liegende bzw. flussabwärts liegende Lateralfläche des proximalen Körpers des Endabschnitts.

According to still further features of the brushes according to the invention:

• - The proximal portion comprises a conductive central column of radial alignment and a sheath which laterally surrounds the central column, and which is formed in a distinct or different material with respect to the central or central column or column;
• The conductive or conductive middle column or column is centered transversally with respect to the reference plane;
• - The guide means are formed by means of two radially upstream and downstream located grooves which are located in one and the same radial plane and each of which is formed at least in the proximal end portion;
• The upstream and downstream lying lateral surfaces extend axially downwardly above the plane of the guide grooves or beyond this plane;
• - The proximal end portion includes an inner shoulder extending axially below the plane of the guide grooves or grooves, of generally rectangular parallelepiped shape and bounded radially by an axial or proximal surface, suitable for interaction with the cylindrical convex external surface of the collector and bounded transversally by two lateral upstream and downstream lateral surfaces, facing each other, of generally axial alignment;
• The lateral facet which is upstream and the lateral downstream facet of the heel are not symmetrical with respect to the reference plane;
• The upstream lateral facet and the downstream lateral facet of the heel are transversely offset with respect to the laterally upstream or downstream lateral surface of the proximal body of the end portion.

The Invention also proposes an electric lathe or device, of the type comprising a rotor having a collector carries, as well as comprising a brush support, the guide means with respect to radial sliding for at least two brushes, of which at least one is executed according to one of the preceding ones Claims, wherein the machine or device characterized is that the two brushes are not identical.

Further Features and advantages of the invention will become apparent upon reading the detailed description below, for better understanding the invention serves and in which in the accompanying drawings Reference is made, in which:

the 1 Fig. 12 is a perspective view showing an end flange of an electric rotating machine shown with internal transverse surfaces oriented upward as viewed in the drawing and equipped with two pairs of prior art coals or brushes;

the 2 is a schematic view in perspective and in enlarged Scale of a prior art brush in conjunction with a portion of a brush support plate or badge providing a radially slidable assembly;

the 3 is a sectional view along an axial and tangential to the brush of 2 present level;

4 is a sectional view through an axial plane along the line 4-4 of 3 ;

the 5 is a view analogous to that of 3 showing a brush according to the prior art;

the 6 and 7 are two views analogous to those of 5 depicting two first embodiments of a brush according to the teachings of the present invention;

the 8th is analogous to that of 3 representing a brush according to the prior art;

the 9 to 11 are views analogous to those of 8th depicting three further embodiments of a brush according to the teachings of the present invention;

the 12 is a view analogous to that of 3 representing a brush according to the prior art;

the 13 to 15 are views analogous to those of 12 again depicting three further embodiments of the brush according to the teachings of the present invention.

In in the following description will be identical, analog or the like Components or components or components with the same reference numerals be specified.

In the following description and the claims, the terms axial, radial, horizontal, vertical, lower, upper, lower, upper, etc. will be used in the following description and claims, in particular with reference to FIGS 1 use and understand in this way.

In 1 is a flange 10 of generally known design in the general form of a horizontal plate or plaque intended to form the hood or the axial lock of an electric motor, the other components or components, and in particular the carcass or the stator and the induction rotor not in 1 are reproduced.

The flange 10 is formed substantially by a metallic badge extending in a radial plane perpendicular to the axis A of the motor, which is the axis of rotation of the rotor (not shown).

The flange 10 is essentially formed by means of a badge made of thick sheet metal 12 whose peripheral S-shaped edge 16 axially struck back upwards, in particular guide means and centering means for the flange 10 with respect to the carcass (not shown) of the engine.

The badge 12 here comprises three attachment ears or projections 18 which extend radially outwardly, which are angularly distributed in a uniform manner with respect to the axis A and each of which has a hole 20 for fixing the motor comprises.

The metallic plaque 12 is by means of an internal plane and horizontal surface 24 limited, which extends axially inward of the engine, that is, upwards, looking at the 1 , wherein a central passage and the rotational guidance of an axial end portion of the rotor shaft (not shown) is made possible.

The metallic plate 12 carries on the internal surface 24 a molded or molded plastic insulating material 30 , carrying various mechanical and electrical components or components, in particular means for guiding the radial sliding of the brushes or coals 34 ,

The badge 30 may be a part that is independently trained and related to the badge 12 is fixed by any suitable means, or even a part which is formed by injection molding or overmolding with respect to the badge 12 , according to the teachings of the document FR-A-2797110 ,

The insulating plaque 30 carries above the internal surface 31 four plaques 32 each of which is generally U-shaped and extends in a radially horizontal plane.

Every badge 32 carries and radially slidably guides a brush or a coal 34 ,

All of the guide stickers 32 are located in one and the same plane, radially orthogonal to the axis A, each having an internal recess 36 includes, bounded laterally by two parallel edges 38 which form two opposing ribs or corrugations for sliding radial guidance of the corresponding brush 34 ,

Every brush 34 is elastically acted radially slidable in the direction of the axis A by means of a brush spring 46 , its helical body 48 axially threaded relative to a mounting finger 50 is mounted, executed from the molding or casting material of the plastic material with respect to the badge 30 ,

The badge 30 thus includes four fingers 50 which are evenly distributed angularly at 90 degrees and each of which is a spring 46 carries for a brush, being a branch 52 the radially outer end surface or the distal 53 the brush 54 and their other branch 56 is firmly in abutment and is included in a complementary notch of the badge 30 ,

In a known manner, every brush 34 electrically connected via a conductive wire 60 with respect to an associated element of the electrical circuit of the motor, wherein the conductive wire is a twisted multi-fiber copper cable.

By way of example, two diametrically opposed brushes with the mass of the metallic plaque 12 whereas the two other brushes share a common conductor as well as a self or inductor 62 concerning the positive pole and with a plug or connector 64 are connected.

It will be described in more detail below a brush 34 according to the prior art with reference to the 2 to 4 described.

The brush or coal 34 is in the form of a rectangular parallelepiped-shaped block, bounded vertically by an upper flat horizontal surface 64 and a flat horizontal lower surface 66 , as well as two vertical lateral surfaces 68a and 68b lying upstream and downstream lying located on the arbitrarily selected direction of rotation of the collector (not shown) as indicated by the arrow F of 2 ,

The brush 34 is also radially bounded by its distal transverse end surface, radially outwardly present at the reference numeral 53 and by the proximal radially inward endface 70 ,

The endface 70 is a cylindrical concave surface whose generatrices are axially parallel to the axis A, which is normally in radial abutment, towards the axis A, against the convex complementary faces, opposite the collector.

The interface of the lateral surfaces 68a and 68b with the radially proximal end surface 70 limited two axially upstream 72a and downstream 72b Bone.

The brush 34 has a generally conceptual symmetry with respect to a median plane PM, here called the reference plane, which is the axial plane representing the radial direction of the sliding of the brush 34 contains.

The plane PM passes through the axis A and, for this purpose, each of the lateral surfaces comprises 68a and 68b a groove or groove 74a . 74b each for the purpose of sliding the guide or the sliding ability therein, wherein in each one edge 38 the recess 36 the guide plaque 32 is included.

The two grooves or grooves 74a and 74b are located in the same horizontal radial plane and are formed symmetrically with respect to the plane PM.

How to do it in particular in the 2 and 3 can detect, determine the gutters 74a and 74b a mainly upper active area of the brush 34 , located globally above the bottom surface 33 the badge 32 , and a lower paragraph 34i of smaller size, also brushed heel 34 called.

In the various examples shown in the figures with respect to both the prior art brush and the various embodiments of a brush according to the present invention, the brush or carbon is 34 Here, by way of example only and not limitation, a two-material brush comprising a peripheral main body 76 and a central core 78 , also called conductive column or column, with which the conductor or the conductive element 60 connected or switched, how to do this in 4 can recognize.

The leading pillar 78 is centered transversally with respect to the reference plane PM.

At the height of the interface between the central core 78 and the sheath or peripheral body 76 If you put the formation of an annular zone layer 80 the mixing of the materials that form the core 78 and the shell 76 form.

According to the prior art and due to the symmetrical identical design of all brushes, which equip a rotating electrical machine and in particular more due to the fact of the evenness or paired arrangement of the brushes and the plaques or conductive fins of the collector, the electrical commutations , determined by the straight ny shape and the symmetrical positioning of the burrs 72a and 72b , takes place at the same time and in an identical manner for all Liche brushes, whereby adverse electromagnetic coupling phenomena may occur.

This perfect symmetry, in particular as a result of the distance Da being the upstream lateral surface 68a from the bottom of the upstream channel or groove 74a separates, equal to the distance Db, the downstream lateral surface 68b from the bottom of the downstream gutter or groove 74b separating, how to do this in particular in the 3 can recognize.

According to a first preferred embodiment of the invention, as in 6 are the upstream lateral surface 68a and the downstream lateral surface 68b parallel, planar and of axial alignment, but they are no longer symmetrical with respect to the reference plane PM.

Consequently is the distance Since here, for example only, smaller than the distance Db.

In the embodiment which in 7 is shown, the two lateral surfaces 68a and 68b also no longer symmetrical with respect to the plane PM.

The lateral surface 68a is a cylindrical concave surface whose generatrix is of generally radial orientation, whereas the lateral surface 68b , located downstream, has a cylindrical convex surface, generally parallel to the concave surface 68a is.

As in the prior art and as in the example of 6 has every lateral surface 68a . 68b about a continuity of the position and the profile with respect to the total axial height, that is indicated at the upper end by the letter "s" and indicated at the lower paragraph by the letter "i".

While in the example of 6 the two lateral surfaces 68a and 68b lateral "offset" with respect to the position of the lateral surfaces of the brush 34 according to the prior art, as in 5 represented, one has in 9 an embodiment shown in which only the downstream lateral surface 68b is greatly offset laterally, still being formed by a flat surface of axial alignment parallel to the lateral upstream surface 68a ,

In the embodiment, the in 10 are shown are the upper sections 68as and 68bs (the lateral surfaces 68a and 68b ) offset axially and laterally, as is the case in the representation of 9 , again their lower sections or facets 68ai and 68bi are also laterally offset with respect to each other and with respect to the center plane PM.

Each of the lower facets 68ai and 68bi (the lateral surfaces 68a and 68b ) is also offset with respect to the upper corresponding section 68as and 68bs , thus the lower paragraph 34i dissymmetric with respect to the upper main section 34s ,

The two lower facets 68ai and 68bi are each offset outward with respect to the upper sections 68as and 68bs ,

In the example which is in 11 is shown, is an embodiment of a brush 34 shown showing a different type of offset of the upper sections 68as and 68bs regarding the lower one 68ai and 68bi the upstream lateral surface 68a and the downstream lateral surface 68b where all of these surface sections or surfaces are planar, parallel and of axial alignment.

One can notice in particular that the upper section 68as laterally offset inwardly with respect to the lower facet 68ai whereas in an opposite way the upper section 68bs in the case of non-symmetry with respect to the upper section 68as offset outwards with respect to the lower facet 68bi ,

In the embodiment, the in 13 is shown is the lower portion of the paragraph 34i the brush 34 according to the prior art with its two Lateralfacetten 68ai and 68bi parallel even in axial alignment and symmetric with respect to the midplane PM, whereas the upper major sections 68as and 68bs the opposite lateral surface are no longer parallel to the plane PM, that is, they no longer have an axial orientation but are inclined here with respect to the reference plane PM, being divergent with respect to each other when viewed vertically from bottom to top.

In the in 14 illustrated embodiment is an analogous embodiment to that of 13 , except that the upper main sections 68as and 68bs the upstream or downstream lateral surfaces 68a and 68b are inclined and converging vertically from bottom to top.

Finally, in the in 15 illustrated embodiment of the paragraph is still in class sischer and symmetrical manner formed with lateral, parallel, flat surfaces with axial alignment, whereas the upper main sections 68as and 68bs parallel and inclined with respect to the center reference plane PM.

In the example which is in 15 is shown in section, and as can also be seen on this figure, the upper main section 34s the brush 34 thus globally the form of a parallelogram, whereas in the 13 and 14 a trapezoidal shape is assumed.

All embodiments of a brush according to the present invention, each shown in the 6 . 7 . 9 to 11 and 13 to 15 , have dissymmetries and are mutually different.

Of Furthermore, it is possible in any embodiment, the overall dimensions of the brush while maintaining to change the existing dissymmetry.

But every coal 34 according to the invention further provides means for guidance in radial slidability corresponding to that of a standard symmetrical brush according to the prior art, that is, here two lateral grooves, as a result of the guide 74a and 74b of which the respective floors are still located at the same distance with respect to each other.

Thus, any brush according to the present invention may be substituted, instead of a conventional brush, and without the need for further modifications of the guide means for conducting the brushes, that is, the guide tags 32 defining the reference plane PM and its position with respect to the axis A.

The invention makes it possible, starting from a set of dissymmetric brushes 34 of different shapes according to the different examples of the invention, arbitrarily provide commutation offset of the brushes by providing brushes with shapes or distinct dissymmetries on one and the same brush support and in an arbitrary or random manner.

you will further recognize that the power of the electric machine or device are not affected, in particular not to the extent that the surface area of the current passage generally remains identical.

The Invention is not limited to a design of brushes, ensures their leadership in grooves or grooves becomes.

It can therefore also apply to any brush whose body are guided in a housing of complementary shape, wherein z. B. is provided that the distal portion radially outward of the brush is determined by the end face 53 which is then routed in the housing in a conventional manner, whereas the proximal active section which interacts with the collector is of dissymmetrical design according to the teachings of the present invention.

Summary

The invention proposes a brush ( 34 ), of the type comprising a proximal end portion, bounded radially by a concave surface ( 70 ) suitable for interaction with a collector and by two lateral surfaces ( 68a . 68b ) face each other, with means ( 74a . 74b ) for guiding the brush ( 34 ), which are radially slidably provided, which provide an axial center plane (PM) for referencing the brush and characterized in that the upstream lateral surface ( 68a ) and the downstream lateral surface ( 68b ) are not symmetric with respect to the reference plane (PM).

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• FR 2797110 A [0003, 0005, 0040]
• - DE 19521376 A [0004]
• - FR 2603141 A [0007]

Claims (14)

Brush ( 34 ), suitable for interaction with a collector of a rotary electric machine, of the type comprising: a proximal end portion whose body is of generally rectangular parallelepiped shape, is radially limited by a proximal axial cylindrical-concave surface ( 70 ) of generally axial orientation (A) adapted to interact with the cylindrical convex external surface of a collector of a rotating electrical machine and bounded transversally by two lateral upstream and downstream opposing surfaces (A); 68a . 68b ) of generally axial alignment; - as well as means ( 74a . 74b ) for guiding the brush ( 34 ) radially slidable in complementary means ( 38 ) a brush support ( 30 . 32 ) of the machine, wherein the guide means determine an axial middle reference plane (PM) of the brush, characterized in that the upstream lateral surface ( 68a ) and the downstream lateral surface ( 68b ) are not symmetric with respect to the reference plane (PM). Brush according to the preceding claim, characterized in that the two upstream and downstream lateral surfaces ( 68a . 68b ) are plane parallel surfaces. Brush according to one of the preceding claims, characterized in that the two upstream and downstream lateral surfaces ( 68a . 68b ) parallel to the reference plane (PM). Brush according to claim 2, characterized in that the two upstream and downstream lateral surfaces ( 68a . 68b ) are inclined with respect to the reference plane (PM). Brush according to claim 1, characterized in that the upstream surface ( 68a ) is a concave or convex cylindrically curved surface with respect to the radial axis. Brush according to claim 1, characterized in that the downstream surface ( 68b ) is a convex or concave cylindrical curved surface with respect to the radial axis. Brush according to one of the preceding claims, characterized in that the proximal section has a conductive center column ( 78 ) of radial orientation, and a shell ( 76 ) which laterally surrounds the central column and which is made in a distinct material relative to that of the central or central column. Brush according to claim 7, characterized in that the middle conductive or conductive column ( 78 ) is transversally centered with respect to the reference plane (PM). Brush according to one of the preceding claims, characterized in that the guide means are formed by means of two radial upstream and downstream grooves ( 74a . 74b ) extending in one and the same radial plane and each of which is formed at least in the proximal end portion. Brush according to claim 9, characterized in that the upstream and downstream lateral surfaces ( 68as . 68bs ) axially above the plane of the guide grooves or grooves ( 74a . 74b ). Brush according to claim 10, characterized in that the proximal end portion has a lower shoulder ( 34i ) extending axially below the plane of the guide grooves ( 74a . 74b ) of generally rectangular parallelepiped-shape and radially bounded by an axial proximal surface adapted to interact with the cylindrical convex external surface of the collector, bounded transversely by two upstream and downstream lateral facets (US Pat. 68ai . 68bi ), facing each other and of generally axial alignment. Brush according to claim 11, characterized in that the laterally upstream facet ( 68ai ) and the laterally downstream facet ( 68bi ) of paragraph ( 34i ) are not symmetric with respect to the reference plane (PM). Brush according to one of claims 11 or 12, characterized in that the upstream lateral facet ( 68ai ) or the downstream Lateralfacette ( 68bi ) of the shoulder transversely offset present with respect to the upstream lateral surface ( 68as ) or the downstream lateral surface ( 68bs ) of the body of the proximal end portion. Electric lathe of the type comprising a rotor carrying a collector and comprising a support ( 30 . 32 ) for brushes ( 34 ), Medium ( 38 ) for radial sliding guide comprising for at least two brushes, one of which is at least executed, according to at least one of the preceding claims, characterized in that the two brushes are not identical to each other.