FR2738683A1 - MECHANICALLY SWITCHED ELECTRIC MOTOR - Google Patents

Abstract

Mechanical switching electric motor comprising a brush holder (8) provided with guide rails (18a, 18b) on a support plate (9), these rails being parallel and in pairs; each time a pair of guide rails (18a, 18b), formed between a receiving opening for a brush (16, 17), serves to penetrate corresponding guide slots (19a, 19b) of the brushes (16, 17) for longitudinal guidance; the guide rails (18a, 18b) conduct electricity at least on the surface to establish contact with the brushes (16, 17).

Description

State of the art

  The invention relates to an electric motor

  mechanical station comprising a brush holder provided with guide rails on at least one support plate, these rails being parallel and in pairs, each time a pair of guide rails

  dage being formed between a receiving opening for a bat-

  lai and used to penetrate corresponding guide slots

  brushes for longitudinal guidance.

  A switching electric motor is already known

  mechanical (WO 84/00645) which includes reactive guide rails

  read on a support plate to constitute a support

  broom; these rails penetrate into suitable guide slots

  prayed made in brooms. The support plate serves to fix a total of two brushes, each brought into contact with a cord

separate.

  Furthermore, according to document DE-42 15 446 Ai, we

  knows a brush holder of an electric motor with switching

  mechanical tion comprising a tube-shaped brush holder

  made on a printed circuit board. The electrical connection

  brushes are made by a separate connection with the che-

  mins conductors of the circuit board prints.

  Advantages of the invention The present invention relates to an electric motor with mechanical switching as defined above, characterized in that the guide rails are electrically conductive

  at least on the surface to establish contact with the brushes.

  The electric motor according to the invention offers the advantage of not requiring separate parts to make contact with the brushes. This allows more construction

simple brush holder.

  According to other advantageous features of the invention:

  - the support plate is a printed circuit plate, equi-

  Sword of electronic components connected by connected paths

ductors.

  - at the level of the guide rails, the support plate includes an electrically conductive coating, connected to the conductive paths on the support plate and used for placing

electrical contact of the brushes.

  - the support plate is provided with two diametrical cutouts -

  opposite to receive a broom each time.

  - the guide rails are each located in a plane passing through the axis of rotation of a motor switch

  electric and perpendicular to this axis of rotation.

  - the cutout is extended in the support plate, radially

  by a cutout receiving an axis bearing.

  - the brushes are biased towards the switch each

  times by a spring pressing against the support plate.

  - the spring consists of an elastic element having a shape comparable to a meander and placed at the bottom of a cutout

of the support plate.

  Drawings Two embodiments of the invention are

  shown in the drawings and will be described below in detail.

  more detailed. Thus: - Figure 1 is a front view of a printed circuit board in the form of brush holder, and

  - Figure 2 shows another example of realization

tion of a brush holder.

  Description of the exemplary embodiments

  Figure 1 shows a support plate 9 in the form of brush support 8. Plate 9 is a circuit plate

  printed; it contains electronic components, not re-

  presented, connected by conductive paths 10. The plate

  support 9 is provided with a cutout 11 delimited by two branches

  ches 12, 13 and generally having a rectangular shape.

  The branches 12, 13 have cutouts 14, 15 open

  to the blank 11; these cutouts are for example stamped.

  These openings 14, 15 form a housing for brushes 16,

  17 also rectangular. The opposite edges of the

  sections 14, 15 form guide rails 18a, 18b. When

  the brushes 16, 17 are placed in their cutout, the rails are

  enter the corresponding guide slots 19a, 19b of the brushes 16, 17. The spacing of the guide rails 18a, 18b is dimensioned so that a brush 16, 17 can be housed sliding longitudinally between the guide rails 18a, 18b in the

cutouts 14, 15.

  The lower half of Figure 1 shows a brush 17 placed in the corresponding cutout 15. Between the brush 17 and the bottom 20 of the cutout 15, a helical spring 21 is placed pushing the brush 17 in the direction of a rotor-shaped switch 22, which is only partially shown; this switch belongs to an electric motor. In the upper half of FIG. 1, the brush 16 has been shown before it is placed in the cutout 14. It appears that the bottom 20 of the cutout 14 comprises, at the level of the support plate 9, a projecting part 23 forming a guide member for the

coil spring 21.

  The guide rails 18a, 18b are provided with a coating

  electrically conductive 24 to ensure the connection of the brushes 16, 17. It is particularly advantageous that the

  covering 24 is carried out at the same time as the paths

  ductors 10 on the printed circuit board 9. The coating 24 is for this purpose made of the same material as the conductive paths 10, for example copper. The brushes 16, 17 are brought into contact by means of the coatings 24

  conductors of electricity. The rotational movement of the commutator

  tor 22 hooks the brushes 16, 17 in guide slots

  19 as a function of the guide play of the rails 18; so we all

  days an electrical contact between the coating 24 and the bases

leave 16, 17.

  The arrangement of the support plate 9 in the form of brush support takes place in a plane passing through the axis of rotation 25 of the switch 22 and a perpendicular 26 to this axis of rotation 25. The arrangement of the support plate 9 can nevertheless be offset in principle perpendicular to the axis of rotation 25, that is to say by 900. The cutout 11 of the support plate 9 can be widened radially, for example

  to receive an axis bearing in a cut lla.

  FIG. 2 shows a second embodiment of a spring 21. The same parts or the same elements, or similar elements as those of the first embodiment,

  have the same references here. Instead of a helical spring

  coidal, an elastic element 27 having a shape of

  meanders. The production of the elastic element 27 is for example possible by a corresponding cutout of the cutout 14 in the support plate 9 made of a circular material.

  baked usual print; it is for example plastic material reinforced with fibers. The elastic element 27 is deformable

  in the direction of sliding of the brushes 16 and during the positioning of the brushes 16, this element is prestressed at the level of the cutout 14. The existence of such an elastic element10 27 in place of a helical spring is particularly advantageous if you do not want significant wear of the

  and thus a long service life of the electric motor without significant spring travel.

Claims (7)

R E V E N D I C A T I 0 N S   1) Electric motor with mechanical switching   taking a brush holder (8) provided with guide rails (18a, 18b) on at least one support plate (9), these rails being parallel and in pairs, each time a pair of guide rails (18a, 18b) being formed between a receiving opening for a brush (16, 17) and serving to penetrate into corresponding guide slots (19a, 19b) of the brushes (16, 17) for the   longitudinal guide, characterized in that the guide rails   dage (18a, 18b) conduct electricity at least in sur-   face to establish contact with the brushes (16, 17).   2) Electric motor according to claim 1, ca-   characterized in that the support plate (9) is a printed circuit plate, equipped with electronic components connected by conductive paths (10).   3) Electric motor according to claim 2, ca-   characterized in that at the level of the guide rails (18), the plate   that support (9) comprises a coating (24) electrically conductive, connected to the conductive paths (10) on the support plate (9) and used for the electrical contacting of brooms (16, 17).   4) Electric motor according to any one of   Claims 2 to 3, characterized in that the support plate   port (9) is provided with two cutouts (14, 15) diametrically op-   placed to receive a broom each time (16, 17).    ) Electric motor according to one of the preceding claims, characterized in that the guide rails (18a, 18b) are each located in a plane passing through   the axis of rotation (25) of a switch (22) of the electric motor   that and a perpendicular (26) to this axis of rotation (25).   6) Electric motor according to claim 5,   characterized in that the cutout (11) is extended in the support plate (9), radially by a cutout (11a) receiving a axis bearing.   7) Electric motor according to claim 1, ca-   characterized in that the brushes (16, 17) are biased di-   rection of the switch (22) each time by a spring (21)   pressing against the support plate (9).   8) Electric motor according to claim 7, characterized in that the spring (21) consists of an element   ment elastic (27) having a shape similar to a meander and placed at the bottom (20) of a cutout (14, 15) of the sup-5 port plate (9).