JPH0865966A - Flat commutator and manufacture thereof - Google Patents

Abstract

PURPOSE: To obtain a flat commutator in which fixing of carbon (graphite) commutator segments to a metal plate with a terminal for connecting a winding and an electrically insulating support is effective, the life of the segment in the case of wearing is long and which can be easily manufactured with a low cost. CONSTITUTION: A flat commutator has a perpendicular brush slide contact surface to the axial direction of a rotor, a plurality of commutator segments 3 insulated by slits 4 from each other directly secured to an electrically insulating support 1, and a metal plate 5 for connecting the segments having a terminal 6 for connecting a winding secured to the outer periphery of the segments 3 parallel with the axial direction of the rotor. The forming of the segments 3 and the fixing of the segments 3 to the support 1 of the segment 3 and the plate 5 for connecting the segments are simultaneously conducted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a commutator incorporated in a small motor, and more particularly to a flat commutator having a brush-sliding surface perpendicular to the axial direction of the rotor, and to manufacture the flat commutator. Regarding the method.

[0002]

2. Description of the Related Art A fan used in a harmful gas atmosphere,
In the case of a motor used in general air, the commutator element that is in sliding contact with the brush of the motor, which is the drive source for a pump used in gasoline that has deteriorated due to acidification, etc., directly comes into contact with harmful gas and deteriorated gasoline. Corrosion wear of the commutator piece progresses remarkably compared with. As a material for the commutator piece, an alloy containing copper or silver as a main component is usually used, but the durability is not satisfactory because of the corrosion and wear as described above. Therefore, it is necessary to use a material having a low corrosiveness as the material of the commutator piece, and carbon is suitable for this. However, since carbon is not malleable like a metal material, the hook portion for connecting the winding of the motor cannot be directly processed on the commutator piece. Therefore, it is necessary to separately form the hook for connecting the winding with a metal material and to join the metal hook and the commutator piece made of carbon.

As a flat commutator in which the metal hook and the carbon commutator piece are integrally joined, hook portions are radially provided on the periphery of the brush sliding contact surface side of the electrically insulating support as many as the commutator pieces. The metal disk is inserted at the same time as the molding of the electrically insulating support, and the surface of the metal disk is soldered or welded with a graphite commutator member having a joint surface pre-plated. There is known a graphite commutator member, a metal disc, and a plurality of commutator pieces that are insulated from each other by forming slits in a part of an electrically insulating support (Patent Application Publication No. 5). (See Japanese Patent Publication No. 502974). That is, as shown in FIG. 6, a metal plate 15 with a hook and a commutator piece 13 made of graphite are superposed and fixed on an electrically insulating support 11 which is a base of a flat commutator.

[0004]

The above-mentioned known flat commutator is troublesome because the joint surface of the commutator member, which is a molded article of graphite, with the hooked metal disk must be plated in advance. High cost. Further, depending on the state of plating, the fixing force of the graphite commutator piece due to solder may be adversely affected. Furthermore, since the graphite molded product undergoes a swelling phenomenon in gasoline, especially deteriorated gasoline, a decrease in the adhesive strength between the plated layer and the graphite molded product cannot be avoided.

When a metal such as copper is used as the plating, the corrosion of the plating lowers not only the fixing force between the graphite commutator piece and the metal plate with the hook but also the conductivity, and the function as the commutator cannot be achieved. . In order to improve the durability of the commutator, it is conceivable to increase the thickness of the commutator piece in the brush pressing direction. However, since the purpose of the flat commutator is to downsize the motor, the commutator piece Cannot be formed thick as described above.

The present invention has been proposed in view of the above-mentioned problems in the conventional flat type commutator, and the carbon (graphite) commutator piece is reliably fixed to the metal plate with hook and the electrically insulating support. In addition, it is another object of the present invention to obtain a flat commutator that has a long life due to wear of the commutator piece and can be manufactured easily and at low cost.

[0007]

In order to achieve the above object, the present invention is directed to a flat commutator having a brush sliding surface perpendicular to the axial direction of the rotor. The commutator piece is directly fixed to the electrically insulating support, and the commutator piece connecting metal plate having winding connection terminals is fixed to the outer peripheral surface of each commutator piece parallel to the axial direction of the rotor. It is configured to exist.

As a method for manufacturing the above flat commutator, at the same time when the electrically insulating support is molded, one end surface of the metal strip plate ring member is formed along the peripheral edge of the electrically insulative support on the brush sliding contact side. Insert-molding, and filling the commutator material containing graphite as a main component in the recess formed by the electrically insulating support and the metal strip ring member assembled to the electrically insulating support. The commutator material is compacted and heated, and a slit for insulation is formed on the surface of the solidified commutator section, the ring material made of the metal strip and the commutator section of the electrically insulating support. It is characterized in that it is divided into a plurality of commutator pieces.

The ring member made of a metal strip is insert-molded so as to be shape-connected to the electrically insulating support. As the material of the commutator piece, a material whose main component is graphite is used. Further, it is suitable that the commutator piece fixing surface of the electrically insulating support is an irregular surface and the commutator piece material is subjected to powder compacting and heating.

[0010]

[Function] The electrically insulating support and the graphite commutator piece are directly and firmly bonded together, and the metal plate for connecting the commutator piece with the winding connection terminal is fixed to the graphite commutator piece and the electrically insulating support. ing. The thickness of the graphite commutator piece can be increased because the metal disk is no longer required between the electrically insulating support and the graphite commutator piece. During molding of the graphite commutator piece, the recess formed by the electrically insulating support and the ring material made of the metal strip plate insert-molded along the peripheral edge of the electrically insulating support on the side of the brush sliding contact is a commutator. It becomes a mold for one-sided molding.

[0011]

EXAMPLES The structure of a flat commutator according to the present invention will be described with reference to the drawings. 1 and 2 are plan views and AA of FIG.
FIG. Reference numeral 1 is a top-shaped electrically insulating support formed of a hard synthetic resin or the like, and a mounting hole 2 for a rotor shaft (not shown) of the motor is opened at the center. A plurality of fan-shaped commutator pieces 3 are directly fixed to a surface of the electrically insulating support 1 on the brush sliding side, that is, a surface perpendicular to the direction of the rotor shaft mounting hole 2, and the side opposite to the fixed side. Is used as the brush contact surface. Each commutator piece 3 is obtained by using graphite as carbon and subjecting a material containing graphite as a main component to powder compacting and heat treatment. The commutator piece fixing surface of the electrically insulating support 1 is formed as an irregular surface due to fine unevenness or a large number of grooves, etc., and the fixing area of the commutator piece 3 of the electrically insulating support 1 is increased. .

The adjacent commutator pieces 3 and 3 are electrically insulated from each other by the slit 4. The slit 4 is formed so as to partially penetrate into the commutator piece fixing surface of the electrically insulating support 1. On the outer peripheral surface of each commutator piece 3 parallel to the rotor shaft mounting hole 2, that is, on the surface along the circumferential direction,
The commutator piece connecting metal plates 5 are individually fixed. At the same time, a part of the commutator element connecting metal plate 5 is embedded in the electrically insulating support 1. A terminal 6 is attached to the metal plate 5 for connecting the commutator piece, and the winding of the rotor is connected to the terminal 6. The terminal 6 is formed by press-punching and bending-molding a metal plate material integrally with the commutator piece connecting metal plate 5.

A small projection 7 is formed on the inner surface of the metal plate 5 for connecting the commutator piece.
Is provided to strengthen the fixation of the commutator piece 3 and the commutator piece connecting metal plate 5. FIG. 3 shows another embodiment of the fixing and strengthening means of the commutator piece 3 and the metal plate 5 for connecting the commutator piece. A small hole 8 is provided in the metal plate 5 for connecting the commutator piece, and the small hole 8 is formed. The molding material of the commutator piece 3 is bitten into.
At the same time, the molding material of the electrically insulative support 1 is made to bite into the other small holes 9 of the metal plate 5 for connecting the commutator piece to strengthen the adhesion between the commutator piece 3 and the electrically insulative support 1.

Next, the manufacturing method will be described. The electrically insulating support is molded as in the conventional case.
As shown in FIGS. 4 and 5, a metal strip plate ring member 5A is embedded along the peripheral edge of the electrically insulating support member 1 on the brush sliding contact side, and one end surface of the ring member 5A is embedded in the electrically insulating support member 1. Insert molding as shown. As in the illustrated example, it is preferable that a part 1A of the material of the electrically insulative support 1 also wraps around the outside of the metal strip plate ring material 5A. The metal strip plate ring material 5A is provided with terminals 6 in advance at predetermined positions on the outer periphery thereof.

A commutator material containing graphite as a main component is filled in a shallow circular concave portion C formed at the center by insert-molding a ring material 5A made of a metal strip on the electrically insulating support 1 and compacted. And heat. That is, the integral electrically insulating support 1 and the ring member 5A made of a metal strip are used as they are as a mold for powder compacting.

Next, as shown in FIGS. 1 and 2, the commutator portion, the ring member 5A made of a metal strip and the surface of the electrically insulating support 1 on the outer periphery of the solidified commutator portion are radiated in the radial direction. Then, the slit 4 is cut to form a plurality of commutator pieces 3 which are divided and insulated by the slit 4. By carrying out the above steps, the three members of the electrically insulating support 1, the commutator piece 3, and the commutator piece connecting metal plate 5, in which the electrically insulating support 1 and the commutator piece 3 are directly fixed, are integrated. A flat commutator is obtained.

[0017]

As described above, the flat commutator of the present invention has the following features.
Since the commutator piece is directly fixed to the electrically insulating support,
There are no unstable factors of the fixing force as compared with the conventional fixing through plating and bonding. Also, when a motor equipped with this flat type commutator is used in liquid such as gasoline, the commutator piece connecting metal plate supports its outer peripheral surface against the swelling of the powder compacting commutator piece. The electrical and mechanical connection of the child piece to the electrically insulating support and the metal plate for connecting the commutator piece is further strengthened. The metal plate for connecting the commutator piece functions to reliably hold the commutator piece against centrifugal force generated during rotation of the commutator. And since there is no metal plate between the electrically insulating support and the commutator piece, the thickness of the commutator can be increased,
There is an effect that the wearable size of the commutator can be sufficiently secured and the life of the commutator is extended.

Further, according to the manufacturing method of the present invention, the commutator piece is molded and the commutator piece is fixed to the electrically insulating support and the metal plate for connecting the commutator piece at the same time. Since there is no need for plating and bonding steps applied to the child, there is an effect that the number of steps can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a flat commutator according to the present invention.

FIG. 2 is a vertical sectional view taken along the line AA of FIG.

FIG. 3 is a vertical cross-sectional view of a joint portion of an electrically insulating support, a commutator piece, and a metal plate for connecting a commutator piece.

FIG. 4 is a plan view showing a method for manufacturing a flat commutator according to the present invention.

5 is a vertical cross-sectional view taken along the line BB of FIG.

FIG. 6 is a vertical sectional view of a conventional flat commutator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrically insulating support 2 Rotor shaft mounting hole 3 Commutator piece 4 Slit 5 Metal plate for connecting commutator piece 6 Winding connection terminal 5A Ring material made of metal strip C C recess for molding commutator part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinya Ashimura 17-36 Misumi Town, Chigasaki City, Kanagawa Prefecture

Claims (5)

[Claims] 1. A flat commutator having a brush sliding surface perpendicular to the axial direction of the rotor, wherein a plurality of commutator pieces insulated from each other by slits are directly fixed to an electrically insulating support to rotate. On the outer peripheral surface of each commutator piece parallel to the axial direction of the child,
A flat commutator characterized in that a metal plate for connecting a commutator piece having a winding connection terminal is fixed. 2. The flat commutator according to claim 1, wherein the commutator piece is a compacted and heated product of a material whose main component is graphite. 3. The flat commutator according to claim 1, wherein the commutator piece fixing surface of the electrically insulating support is an irregular surface. 4. The flat commutator according to claim 1, wherein the metal plate for connecting the commutator piece is shape-connected to the electrically insulating support. 5. A step of insert-molding one end surface of a metal strip made of a metal strip along the peripheral edge of the electrically insulating support on the side of the brush sliding contact, simultaneously with the molding of the electrically insulating support. Of a commutator material containing graphite as a main component in a recess formed by a flexible support and a ring material made of a metal strip attached to the electrically insulating support, and powder molding of the commutator material The process of heating, the solidified commutator section, the metal strip plate ring material around the periphery and the commutator section side surface of the electrically insulating support are provided with slits for insulation, and a plurality of commutator pieces are provided. A method for manufacturing a flat commutator, which comprises a step of forming in a divided manner.