FR2699017A1 - Noise decoupling brush holder. - Google Patents

Abstract

In noise-decoupled brush holders for switch machines with a machine body to which is attached a support member (10) itself carrying brush ducts (14) each receiving a sliding switch brush (15) Axially, the sound damping is improved by fixing the brush ducts (14) on the support member (10) by spring spacers, elastic (18-21). The brush ducts (14) are fixed on an intermediate support (13) and the spring spacers (18-21) are provided between this intermediate support and the support member (10).

Description

"Noise decoupling brush holder" The invention relates to a holder

  of noise decoupled brushes for switching machines comprising a support member fixed in the body of the switch machine, this support member being provided with brush ducts for receiving each time a switch brush, sliding axially in the duct .

  The switching brushes of

  mutations, such as direct current motors, create generated operating noise

  by the eccentricity of the switch, the jumps to the passa-

  ge from one switch plate to another, etc; these noises are transmitted by the brush holder to the body of the machine which emits them To eliminate these operating noises to a very large extent, we

  uses noise decoupled brush mounts.

  In the case of a known brush holder, of this type (DE-GM 91 06 978), the molded rubber parts are placed between the carbon brushes and the duct or channel receiving the brushes. brushes, there are rubber elements between the brush holder support and the machine body. However, in the case of rubber parts, you lose the decoupling effect when these parts are too tight during assembly and when

  works at too low temperatures.

  The present invention aims to remedy these drawbacks and for this purpose relates to a brush holder corresponding to the type defined above, characterized in that the fixing of the brush conduits on the support member is done using

  spacers with spring elasticity.

  The brush holder according to the invention has the advantage of keeping unchanged the decoupling effect of the elastic spring strut in a range of

  temperature between -400 C and + 850 C, i.e.

  say throughout the range of practical use of the motor In addition, the spring spacer allows a softer decoupling leading to a greater damping of noise The choice of material and the geometry of the elastic spring spacer allows influence the resonant frequency and damping and thus achieve decoupling

optimum noise.

  According to an advantageous embodiment of

  the invention, at least two pipes with diameter brushes

  trally opposite on the support are rigidly fixed on an intermediate support and the spring spacer is provided between the brush support and the member that carries the brush support In this constructive embodiment, the application forces of the brush are not do not exert on the spring struts and these can be performed optimally, independently of the brush application forces If such an intermediate support is dispensed with, and that

  the brush holder is fixed directly to the organ-

  who wears it, avoid excessive travel of the brushed duct by form stops

appropriate.

  Drawings. The present invention will be described below in more detail with the aid of the accompanying drawings in which: FIG. 1 is a top view of a

  brush holder of a small DC motor.

  Figures 2 and 3 respectively show a section along lines IIII and III-III of the

figure 1.

  Figure 4 shows a view similar to

  that of FIG. 1 of a modified brush holder.

  Figure 5 is a section along the line

V-V of figure 4.

  Description of the exemplary embodiment.

  Figure 1 shows a top view and Figures 2 and 3 in two sections, a noise decoupling brush holder for a small motor

  direct current, as an example of a switching machine

  tion; this support consists of a member 10 in the form of an insulating plate 11 represented here as a disc, and having in its middle a large cutout 12 receiving an intermediate support 13 also in the form of a disc of insulating material, coming flush with the upper face and the underside of the insulating plate 11 The intermediate support 13 is provided, in a radial alignment, with two diametrically opposed conduits or brush channels 14, each receiving a switch brush or graphite brush 15 axially sliding The connection cord 16 of the brushes, ensuring the electrical supply, passes through a longitudinal slot 17 of the brush duct or channel 14 The brush pipes 14 themselves are made of sheet metal; they can also be made of injected plastic. The brushes 14 are closed at a front end; a brush spring, not shown here, is supported between this end which constitutes the bottom of the conduit and the carbon brush 15 which presses the brush 15 against the switch of the motor

direct current.

  The intermediate support 13, in the form of a disc provided with a circular central hole 26 for the passage of the switch, is held against the insulating plate 11 by elastic spacers 18, 21 In FIG. 1, the upper half-view and the half - lower view of the brush holder, show two different embodiments of the spring spacers 18, 21 In the upper half-view, the elastic spacers 18, 19 are located in the plane of the insulating plate 11 as also appears in the view in section of Figure 2 In the lower half-view, the spring spacers 20, 21 are perpendicular to the insulating plate 11 as shown in the sectional view of Figure 3 The spring spacers 18-21 have a shape similar to meanders, the spring struts 18, 20 comprising two meander arcs and the spring struts 19, 21 only a meander arc It is clear that in one embodiment of the brush holder there will be preferably four identical spring spacers 18-21, so that the spring spacers 18-21 in Figures 1-3 represent four different possibilities of

  making spacers Preferably-

  the, the intermediate support 13, in the form of a disc, the spring spacers 18-21 and the insulating plate 11 are injected in a single piece of plastic material. When the brushes ducts 14 are also made of plastic material, they are

  injects at the same time on the intermediate support 13.

  The geometry and material of the brush holders 18-

  21 makes it possible to influence the resonance frequency of the oscillations of the brushes and thus the damping of the

  brush noises, to optimize these parameters.

  The brush holder, shown in top view in Figure 4 and in section in Figure 5, is modified insofar as the intermediate support 13, disc-shaped, is parallel and at a certain distance from the insulating plate it 'The insulating plate It' no longer needs in this case the cutout 12 but it only has the circular central hole 27 for the passage of the switch of the DC motor In the same way as that described, the two brushes ducts 14 and the carbon brushes 15 as well as the compression springs which these conduits receive are fixed on the intermediate support 13 The brush conduits 14 are thus provided on the face of the intermediate support 13, facing the plate

insulating it.

  The intermediate support 13 is itself coupled to the insulating plate 11 'by four spacers

  spring loaded 22-25 These four spring loaded spacers 22-

  are in the form of rods, as shown for the spring spacer 22 of FIG. 5 For a softer decoupling, it is also possible to produce spring paths 22-25 in the form of meanders or S as is shown for the spring spacer 23 of FIG. 5 The front ends of the S-shaped spring spacers are connected respectively to the insulating plate 11 'and to the intermediate support 13 When the intermediate support 13, the insulating plate il' and the spacers to spring 22-25 are made of plastic, they are injected in one piece and if the brushes 14 are also made of plastic, they are molded in

  same time on the intermediate support 13.

  The invention is not limited to the embodiments described above. Thus, it is not necessary for the brush conduits 14 to be rigidly fixed on the intermediate support 13 and for the latter to then be coupled to the insulating plate 11, 11 'by spring spacers 18-21 or 22-24 Furthermore, the various conduits or brush channels 14 can also be connected directly to the plate of insulating material 11 or 11' by spacers with

corresponding spring.

Claims (4)

CLAIMS) Noise decoupling brush holder for switch machines, comprising a support member (10) fixed in the body of the switch machine, this support member being provided with brush ducts (14) for receiving each time a switch brush (15), sliding axially in the duct, characterized in that the fixing of the brush ducts (14) to the support member (10) is carried out using spacers with elasticity of spring (18-21; 22-25).   2) brush holder according to claim 1, characterized in that at least two diametrically opposite brush conduits (14) are provided on the support member (10), being rigidly fixed on an intermediate support (11 ) and the spring spacer (18-21; 22-25) is provided between the support   intermediate (13) and the support (10).   ) Brush holder according to claim 1 or 2, characterized in that the support member (10)   is preferably a circular plate (11, 11 ').   ) Brush holder according to claim 3, characterized in that the plate (11, 11 ') is in   especially injected plastic.   50) Brush holder according to one of   claims 1 to 4, characterized in that the   spring spacers (18-21; 22-25) are produced   made of plastic, preferably by injection.   ) Brush holder according to claim 4 and 5, characterized in that the brush conduits   (14) are made of plastic, preferably   injection molding and the spring spacers (18-   21; 22-25) are formed in one piece with the   plate (11, 11 ') and the brushes conduits (14).   70) Brush holder according to one of   claims 3 to 6, characterized in that the   spring spacers (18-21) are located in the plane of the plate or are folded relative to   this, preferably at a right angle.   80) Brush holder according to one of claims 1 to 7, characterized in that the spring spacers (18-21, 23) have a meandering shape with at least one meandering arc.   ) Brush holder according to one of the res-   dications 2 to 8, characterized in that the intermediate support (13) is disc-shaped and lies in the plane of the plate (11, 11 ') or at a distance of it, in parallel. ) Brush holder according to one of   claims 2 to 9, characterized in that the support   intermediate (13) is made of plastic, preferably by injection.   11 i) Brush holder as claimed   cation 10, characterized in that the brush duct (14) is made of plastic, being produced in one piece with the intermediate support (13), preferably by injection.   ) Brush holder as sold   cation 11, characterized in that the intermediate support   diary (13), the spring spacers (18-21; 22-25)   and the plate (11, II ') are in one piece.