JP2013046530A - Electric brush for dc motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric brush for a DC motor which is suitably adopted as a small electric brush and prevents or inhibits fastening of the electric brush which is caused by wear powder intruding into a holder even if the wear powder of the electric brush intrudes into the holder while eliminating the need of an accessory device specifically used for removing the wear powder.SOLUTION: An electric brush 20 has multiple protruding spherical surfaces 22, which are integrally formed during burning, on a surface 20f slide-contacting the holder side.

Description

  The present invention relates to an electric brush for a DC motor that can be suitably used for a DC motor having a holder and an electric brush that is slidably held in the holder.

In general, as a holding structure for an electric brush of a DC motor, for example, a structure is adopted in which an electric brush is slidably inserted into a pocket-shaped holder made of brass and the electric brush is pressed from above.
In this type of structure, a rectangular parallelepiped electric brush 120 is movable up and down in the pocket-shaped holder main body 18 like a holder 110 shown in FIG. (Refer to FIGS. 4 and 5) is in sliding contact with a commutator (not shown).

  By the way, the electric brush 120 is a consumable part, and the abrasion powder of the electric brush 120 is generated from the lower end portion 120 t where the electric brush 120 slides on the commutator 6. Then, the generated wear powder enters between the inner surface of the cage body 18 and the outer surface of the electric brush 120 from below the electric brush 120. Therefore, the vertical movement of the electric brush 120 may be hindered by the wear powder that has entered the cage 110.

  Therefore, as a measure for preventing the invasion of the electropowder wear powder into the cage 110, a plurality of concave surfaces 121u may be provided by cutting on the side surface of the electroprinter 121 as in the case of the electroprinter 121 shown as an example in FIG. (In the example of the figure, three cuttings are performed obliquely with respect to one side surface). As another measure, for example, in Patent Document 1, a vent hole for ejecting compressed gas from the outside is formed in the cage, and air is blown from the vent hole to a portion facing the electric brush. A method for cleaning a DC motor is disclosed.

JP 2008-29101 A

  However, the method of providing a concave surface on the side of the electric brush by cutting is difficult for a small electric brush, and its manufacturing cost is high. In addition, a cleaning method in which a ventilation hole for ejecting compressed gas from the outside of the cage is formed and air is blown into the part facing the electric brush from the ventilation hole is provided with an additional device dedicated to removing abrasion powder. Since it can not be carried out unless it is prepared and attached, the cost of the facility and the running cost are also increased. Therefore, there is still room for examination in any measure.

  Therefore, the present invention has been made paying attention to such problems, and can be suitably employed for a small electric brush, while eliminating the need for an auxiliary device dedicated to removing abrasion powder. The purpose of the present invention is to provide an electric brush for a DC motor that can prevent or suppress the sticking of the electric brush due to the wear powder that has entered the cage even when the abrasion powder of the electric brush has entered the cage. Yes.

In order to solve the above problems, the present invention provides an electric brush used in a DC motor having a holder and an electric brush that is slidably held in the holder. The surface slidably contacting the container side has a plurality of convex spherical surfaces formed integrally during firing.
Here, it is preferable that the plurality of convex spherical surfaces are arranged in a staggered diagonal position with respect to the other adjacent convex spherical surfaces.

  According to the present invention, the electric brush has a plurality of convex spherical surfaces (hereinafter also referred to as “reverse dimple shape”) integrally formed at the time of firing on the surface that is in sliding contact with the cage side. An uneven shape can be formed on the surface of the electric brush. Therefore, it is suitable for forming a concavo-convex shape on the surface of a small electroprinter. And according to this "inverse dimple shape", since the sliding contact is made between the apexes of the plurality of convex spherical surfaces and the inner wall surface of the cage, the periphery of the convex spherical surface functions as a concave portion. Thus, the wear powder can be released from the concave portion around the convex spherical surface to the outside of the cage without providing an auxiliary device dedicated to the removal of the wear powder. Therefore, even when the abrasion powder of the electric brush enters the holder, it is possible to prevent or suppress the adhesion of the electric brush due to the abrasion powder that has entered the holder.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view for explaining an embodiment of a DC motor having an electric brush according to the present invention, which is partially broken away. It is a perspective view explaining one Embodiment of the holder | retainer part of the direct-current motor which has the electric brush which concerns on this invention. FIGS. 3A and 3B are diagrams illustrating the electroprinter of FIG. 2, in which FIG. 2A is a front view, FIG. 2B is a right side view, and FIG. 2C is a plan view, and FIGS. The container body (broken figure) is also shown. It is a perspective view explaining an example of the holder | retainer part of the DC motor which has the conventional electric brush. It is a figure explaining the 1st example of the conventional electric brush, The figure (a) is the front view, (b) is a right view, (c) is a top view. It is a figure explaining the 2nd example of the conventional electric brush, The figure (a) is the front view, (b) is a right view, (c) is a top view.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate.
As shown in FIG. 1, the DC motor 1 has a stator 2 and a rotor 3 in a cover 7. The rotor 3 includes a shaft 4, an armature 5, and a commutator 6, and is supported in the cover 7 so as to rotate integrally. A plurality of cages 10 are arranged to face the outer peripheral surface of the commutator 6.

  As shown in FIG. 2, each retainer 10 holds an electric brush 20 so as to be slidable inside, and slides the held electric brush 20 with the facing commutator 6. The DC motor 1 receives a DC current fed through the electric brush 20 by the commutator 6, thereby generating a magnetic field in the armature 5 formed with a coil, and a magnet on the stator 2 side formed around it. Thus, the rotational force of the shaft 4 is obtained.

Next, the cage 10 will be described in detail.
As shown in FIG. 2, the cage 10 includes a base portion 12, a body portion 14, a pressing arm 16, and a brass cage body 18 that has a pocket shape (a rectangular frame in plan view). Have. The base portion 12 attaches the entire cage 10 to the DC motor 1. The holding arm 16 made of a flexible leaf spring has a proximal end portion 16a rotatably attached to the main body portion 14 by an attachment pin 16b. An electric brush 20 is accommodated in the holder body 18. The electroprinter 20 is a carbon member having a rectangular parallelepiped shape, is in sliding contact with the inner surface 18n of the cage body 18, and is movable up and down within the cage body 18. Further, the electric brush 20 is urged in the direction of the arrow D in FIG. 2 so that the commutator 6 and the lower end 20 t are in sliding contact with the pressing arm 16.

  More specifically, the electric brush 20 is attached to the distal end portion 16 c of the pressing arm 16. The pressing arm 16 urges the electric brush 20 to be in sliding contact with the commutator 6 toward the commutator 6 by a pressing spring 17 rotatably attached to the main body portion 14 by a support pin 16d. The electric brush 20 is supplied with power from a cable terminal 21 a attached to the tip of a cable 21 joined to the electric brush 20.

  Here, as shown in FIG. 3, in the electroprinter 20, a plurality of convex spherical surfaces 22 integrally formed at the time of firing are formed on a surface 20 f that is four side surfaces of the rectangular parallelepiped shape. The plurality of convex spherical surfaces 22 are arranged in a staggered oblique position with respect to the other adjacent convex spherical surfaces 22, and are arranged so as to form a “reverse dimple shape” as a whole. . In the example of the present embodiment, the shape of each convex spherical surface 22 and the distance from other adjacent convex spherical surfaces 22 are the same, and the height of each convex spherical surface 22 is set so as to slide with the cage body 18. The dimensions are as high as possible without any problem. In the example of this embodiment, the height of the convex spherical surface 22 is about 0.5 mm.

Next, the operation and effect of the above-described electric brush 20 will be described.
The electric brush 20 is movable up and down in the cage body 18 as described above, and the lower end portion 20 t is in sliding contact with the commutator 6. Here, the electric brush 20 is a consumable part, and the abrasion powder of the electric brush 20 is generated from the lower end 20 t of the electric brush 20 that slides on the commutator 6. The generated wear powder can enter between the inner surface 18n of the cage body 18 and the outer surface of the electric brush 20 from below the electric brush 20. Therefore, if the abrasion powder is not excluded, the vertical movement of the electric brush 20 may be fixed by the abrasion powder that has entered the cage body 18.

  However, according to this electrobrush 20, the surface of the electrobrush 20 has a plurality of convex spherical surfaces 22 arranged in an “inverted dimple shape” and integrally formed during firing. Since the sliding contact is made between the apex of the cage and the inner wall surface of the cage body 18, the periphery of the convex spherical surface 22 functions as a concave portion. Thus, the wear powder can be released from the concave portion around the convex spherical surface 22 to the outside of the cage body 18 without providing an accessory device dedicated to removing the wear powder. Therefore, even when the abrasion powder of the electrobrush 20 enters the cage main body 18, it is possible to prevent or suppress the adhesion of the electric brush 20 due to the abrasion powder that has entered the cage main body 18.

Since the plurality of convex spherical surfaces 22 are integrally formed at the time of firing, an uneven shape can be formed on the surface of the electric brush 20 without using cutting. Therefore, even if the electroprinter 20 is small, it is suitable for forming an uneven shape on the surface.
Furthermore, according to this electroprinter 20, since the plurality of convex spherical surfaces 22 are arranged in a staggered diagonal position with respect to the other adjacent convex spherical surfaces 22, for example, a lattice shape that simply extends vertically and horizontally. Compared with the case where the convex spherical surface 22 is arranged at the position of the intersection, the effect of scraping the wear powder is more advantageously produced. Therefore, it is suitable for preventing or suppressing the sticking of the electric brush due to the infiltrated wear powder, and the sliding contact position with the cage main body 18 side is evenly arranged by being arranged in a staggered diagonal position. This is also suitable for distributing and preventing local wear on the inner wall surface of the cage body 18.

As described above, according to this electrobrush 20, it is suitable for forming a concavo-convex shape on the surface of a small electrobrush 20, and a dedicated accessory device for the purpose of removing wear powder is used. Even if it is not necessary, even if the abrasion powder of the electric brush 20 enters the holder 10, it is possible to prevent or suppress the adhesion of the electric brush 20 due to the abrasion powder that has entered the holder 10.
Note that the electric brush for a DC motor according to the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 DC motor 2 Stator 3 Rotor 4 Shaft 5 Armature 6 Commutator 10 Cage 12 Base part 14 Body part 16 Holding arm 17 Holding spring 18 Cage body 20 Electric brush 21 Cable 22 Convex spherical surface

Claims (2)

  An electric brush used in a DC motor having a holder and an electric brush that is slidably held in the holder, and the electric brush is integrally formed on a surface in sliding contact with the holder side during firing. An electric brush for a DC motor, characterized by having a plurality of convex spherical surfaces.   2. The electric brush for a DC motor according to claim 1, wherein the plurality of convex spherical surfaces are arranged in a staggered diagonal position with respect to other adjacent convex spherical surfaces.

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