JPH0122386Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to an electric brush used for small motors, etc., and more specifically, it relates to a structure for attaching the brush body to the brush plate in an electric brush in which the brush body is integrally assembled with the brush plate. be.

BACKGROUND ART Electric brushes, in which a brush body is assembled to a brush plate and the brush body is fixed to the brush plate by a pressing force generated at a contact portion between the two, are widely used for small motors and the like.

However, such electric brushes have the following drawbacks because the connection between the brush body and the brush plate relies on the pressing force generated by the springiness of the brush plate.

(1) If the dimensional accuracy of the brush body or brush plate decreases even slightly, sufficient adhesion between the two cannot be achieved.

(2) The contact resistance between the brush body and the brush plate is large. When a large current is applied to such a brush, heat is generated from the contact portion between the brush body and the brush plate. Further, in this case, contact between the brush body and the brush plate becomes even more unstable due to annealing or oxidation due to heating of the brush plate.

This invention provides a new connection structure between the brush body and the brush plate, reduces the contact resistance between the two, eliminates the need for pressure support that requires a high degree of dimensional accuracy, and improves brush productivity. The purpose is to increase.

The electric brush of this invention has two
A conductive metal piece is buried in the upper part of the brush body so as to penetrate through it leaving two protrusions, and the metal brush plate and the conductive metal piece are placed in contact with the head of the brush body.
It is designed to be fixed at two protrusions.

Here, the brush body is made of graphite alone or made of graphite and a metal such as copper or silver.

The conductive metal piece is made of copper, silver, brass, etc. and is used in the form of a round bar, square bar, flat plate, or the like. The direction in which the conductive metal pieces are buried is parallel to the longitudinal direction of the brush plate. The reason why the protrusions are left behind at both ends is to allow the conductive metal piece and the brush plate to be fixed to each other at the protrusions. As the fixing method, spot welding, ultrasonic welding, soldering, screw nut fixing, etc. can be widely used. Further, the conductive metal pieces may be embedded integrally with the brush body during molding.

The brush plate is made of a material with a certain degree of elasticity so that the brush body is pressed into contact with the commutator.

Examples of this invention will be described below based on the drawings.

FIG. 1 is a perspective view showing a brush body and a conductive metal piece, and FIG. 2 is a perspective view of an electric brush.

In the figure, reference numeral 1 denotes a brush body, which is shaped into a rectangular parallelepiped, and has a rectangular protrusion 2 at its head. A plate-shaped conductive metal piece 3 is embedded in the upper part of the brush body 1, and both ends of the conductive metal piece 3 are made to protrude from the circumferential surface of the brush body 1.

Reference numeral 4 designates a brush plate made of metal, which is provided with a through hole 5 and is fitted with a protrusion 2 of the brush body 1. Brush plate 4
is brought into contact with the head of the brush body 1, and has two bent portions 6, 6' corresponding to the circumferential surface of the brush body 1.
is provided so that the back surface of the brush plate 4 and the surface of the conductive metal piece 3 are on the same plane.

The brush plate 4 and the conductive metal piece 3 are fixed by spot welding at positions 7 and 7'.

Falling off of the brush body 1 from the brush plate 4 is prevented by the adhesion between the brush plate 4 and the conductive metal piece 3. Displacement of the brush plate 4 of the brush body 1 in the longitudinal or lateral direction is prevented by fixing the brush plate 4 to the metal piece 3 and fitting the protrusion 2 into the through hole 5.

Since the current from the brush plate 4 to the brush body 1 passes through the metal piece 3 fixed to the brush plate 4, contact resistance is not a problem.

In this embodiment, the attachment strength of the brush body 1 to the brush plate 4 is increased by fitting the protrusion 2 and the through hole 5, but the protrusion 2 and the through hole 5 may be omitted.

As explained above, in this invention, the brush body is assembled to the brush plate by fixation via a conductive metal piece, so that the contact resistance between the two is reduced. In addition, conventional pressure support is no longer required, so
Problems with the dimensional accuracy of the brush plate and brush body are resolved, and productivity is improved.

[Brief explanation of drawings]

Figures 1 and 2 show one embodiment of this invention; Figure 1 is a perspective view showing a state in which conductive metal pieces are embedded in the brush body, and Figure 2 is a perspective view showing an electric brush. It is. 1... Brush body, 3... Conductive metal piece, 4...
Brush plate, 7, 7'... fixed place.

Claims (1)

[Scope of utility model registration request] A conductive metal piece is buried in the upper part of the brush body so as to pass through the circumferential surface of the brush body leaving protrusions at both ends, and the metal brush plate is brought into contact with the head of the brush body. An electric brush characterized in that a brush plate is fixed to a protrusion of the conductive metal piece.