JPS5941590Y2 - Small DC motor brush device - Google Patents

Description

[Detailed description of the invention] [Technical field] This invention belongs to the field of technology related to motors, particularly small DC motors.

[Background Art] In a conventional small DC motor using a flat plate type commutator, as shown in Fig. 1, a flat plate type commutator is used, in which a plurality of fan-shaped segments a are divided by slit grooves l and arranged radially. Since the branch brush B having a plurality of branch pieces is brought into contact with the child A so that the contact portions d of each branch piece are in a straight line, each branch piece of the brush B crosses the slit groove portion l. The disadvantage was that the switching of the resulting currents occurred simultaneously and abruptly, resulting in high electrical wear on the brushes and segments.

In order to solve this drawback, as shown in the second figure, each branch piece b1 of the brush B. b2. Contact part at of b3 with segment a
.
b2. In this method, the force at the contact part d1 of the branch piece b1 is determined by the spring pressure of the branch piece b1 and the friction coefficient of the contact part, and is 0, as shown in FIG. Since the movement direction of the contact part d2 is the tangential direction, the contact part d2 has the center 0 of the flat commutator A and the contact part b1.
A force f is applied in the direction perpendicular to the o - d I line connecting the lines, and a force f1 that causes lateral vibration acts on the branch b1, and the contact part d3 and 0 are connected to the branch b3 for the same reason as the branch b1. Force f2 is applied in the 0-d3 direction connecting branch piece b3
This has the disadvantage that lateral vibrations occur, which increases brush wear and shortens the life of the motor.

[Purpose of the invention] This invention was made in view of the above-mentioned circumstances, and aims to extend the life of the brush by eliminating the lateral vibration of the brush.
The purpose of this is to extend the life of the motor.

[Disclosure of the invention] In view of the drawbacks of the conventional example as explained above, in this invention, as shown in FIG.
a2. A plurality of branch pieces bx,
b2. b3 is the contact part dt with the segment of each branch piece
, d2. Shift da and each branch piece bl.

b2. The objective was to be achieved by making contact with b3 at different facing angles.

This invention will be explained below with reference to FIG. 5, which is shown as a schematic diagram.

In FIG. 5, each branch piece b1. b2°b3 are actually the contact portions d1. d2. Although it extends to the position da, it is shown briefly for convenience of explanation.

As can be seen from this figure, the facing angle of each branch piece is the center O of the flat commutator A and the contact portion d1 of each branch piece. d2. Lines connecting d3: o-d1 line, o-d2 line, o-d3
Line and each branch piece bt, b2. b3 are arranged at right angles to each other, and the force at the contact portion of each branch piece coincides with the axial direction of the branch piece, thereby generating a force that tends to bend each branch piece laterally.

That is, in this case, as shown in FIG. 3, for example, a force corresponding to the force f1 generated in a direction perpendicular to the axial direction of the branch piece b1 is not generated, and lateral vibration is generated in each branch piece. do not.

The resultant force of the forces acting on each branch piece indicated by the arrows in FIG. 5 acts on the base that supports each branch piece, but since this is firmly fixed, it does not vibrate.

As a result, the lateral vibration of each branch piece becomes much smaller than in the conventional example as shown in FIG. 3, and electrical wear is reduced.

As explained above, this invention is based on a planar commutator in which a plurality of fan-shaped segments are divided by slit grooves and arranged radially, and a branch brush having a plurality of branch pieces is attached to the segment of each branch piece. The contact portions of the branch pieces are shifted and the opposing angles of the branch pieces are brought into contact so that they are perpendicular to the line connecting the center of the flat commutator and the contact portion of each branch piece. Therefore, the switching of the current generated when the brush crosses the slit groove portion is carried out gradually, there is no lateral vibration of the branch piece, and wear of the brush and segments can be easily prevented, which has the effect of lengthening the life of the motor.

[Brief explanation of the drawing]

Figures 1 and 2 show a conventional example, where A is a plan view, the opening is a front view of the same as above, Figure 3 is an explanatory diagram of the operation of the conventional example shown in Figure 2, and Figure 4 is an implementation of the present invention. An example is shown in which A is a plan view, the mouth is a front view of the same as the above, and FIG. 5 is a schematic diagram for explaining the operation of the same. A is a flat plate commutator, a is a segment, I is a slit groove, B is a branch piece, b+, b2. b3 is a branch piece, d
l, d2. d3 is a contact part.

Claims (1)

[Scope of utility model registration request] A branch brush having a plurality of branch pieces is attached to a flat plate type commutator in which a plurality of fan-shaped segments are divided by slit grooves and arranged radially. A brush device for a small DC motor in which each branch piece is brought into contact with the line connecting the center of a flat plate type commutator and the contact portion of each branch piece so that the opposing angles of the pieces are perpendicular to each other.