JPH09149604A - Molded commutator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the strength and the stability in quality of a molded commutator which are equivalent to those of a calking-type commutator and to prevent the commutator segments from jumping out even if the commutator is broken by the deterioration of resin. SOLUTION: A protrusion 4 is provided on the rear of each commutator segment 2 of a commutator. A recess 7 is formed in the protrusion 4 in an axial direction. A reinforcing ring 3 made of insulating material is inserted into the respective recesses 7 of the commutator segments 2 to unify the reinforcing ring 3 with the respective commutator segments 2 by molding. With this constitution, the strength and the stability in quality of the molded commutator which are equivalent to those of a calking-type commutator can be realized. Further, even if resin is deteriorated by heat, vibration, etc., and loses a force to hold the commutator segments 2 and hence there is the possibility of the jumping-out of the commutator segments 2, the jumping-out of the commutator segments 2 can be avoided by the reinforcing ring 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the structure of a mold commutator used in a commutator motor.

[0002]

2. Description of the Related Art Rectifiers used in commutator motors are roughly classified. A large number of commutator pieces are arranged radially to form a cylindrical shape and integrally molded with resin, and each commutator piece is fixed. There are two types: a molded commutator, and a caulking commutator fixed by caulking with an insulating paper piece interposed between a large number of commutator pieces and a boss and between the commutator pieces. .

The main characteristic of the two types of commutator when compared is that the caulking type commutator has a large holding force for the commutator piece but is expensive. Further, it can be said that the price of the molded commutator is low, but the holding power of the commutator piece is small. The commutator of the present invention relates to a mold commutator.

[0004]

The mold commutator has a drawback in that the commutator piece is fixed only by the resin and the bonding force is weak. Since the commutator motor rotates at a high speed of tens of thousands of revolutions, a large centrifugal force is applied to the commutator portion, and further vibration and heat are generated. By repeating the rotation and stop of the rotor of the electric motor, the resin strength of the mold commutator gradually deteriorates. Then, a hair crack is generated in the resin portion, and the crack gradually grows due to centrifugal force or vibration, and in the worst case, the commutator piece cannot withstand the centrifugal force and may scatter during rotation.

The present invention has been made in view of such circumstances, and even in the case of a mold commutator, it is possible to realize strength and quality stability equivalent to those of the caulking method. Then, it is an object to provide a molded commutator capable of preventing the commutator piece from popping out even when the commutator is broken due to deterioration of the resin.

[0006]

[Problems to be Solved by the Invention] Protruding portions are provided on the back surface of each commutator piece, and a concave portion is formed in the axial direction of the protruding portion. By molding the child piece and the reinforcing ring integrally, it is possible to achieve the same strength and quality stability as the crimping type even in the molded commutator, and the resin is deteriorated by heat and vibration and rectified. The problem is solved because the reinforcing ring can prevent the commutator piece from popping out even if the commutator piece may lose its force to hold the child piece and pop out.

[0007]

[Function] By switching on the commutator motor,
The mold commutator rotates at a high speed of tens of thousands of revolutions per minute. Due to this high speed rotation, centrifugal force is applied to the commutator, and vibration is generated in the commutator portion. In addition, the commutator gradually becomes hot due to the long energization time.

Then, the switch of this electric motor is turned ON-O.
By repeating FF, the resin holding the commutator pieces and the like gradually deteriorates in strength due to deterioration over time. This deterioration causes minute cracks in the resin part,
By repeating -OFF, this crack gradually becomes a large crack. By repeating this ON-OFF, the holding force of the resin supporting the commutator piece reaches the limit, and the commutator piece tends to scatter. However, protrusion of this commutator piece is restricted by a reinforcing ring provided in the commutator.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on an embodiment shown in the drawings. FIG. 1 is a cross-sectional view of the essential parts of a mold commutator according to an embodiment of the present invention, and FIG. Longitudinal sectional view (sectional view taken along line AA) of a main part of a mold commutator according to an embodiment.
FIG. 3 is a perspective view of a commutator piece according to an embodiment of the present invention.

1 and 2, a large number of commutator pieces 2 are provided.
Are radially juxtaposed and cylindrically aligned. A reinforcing ring 3 made of an insulator is inserted in the recess 7 of the commutator piece 2. In addition, a collar 8 made of metal is provided in the center of the commutator piece 2 formed in a cylindrical shape, and the collar 8 is provided with a shaft hole 6. The commutator piece 2, the reinforcing ring 3 and the collar 8 are integrally molded with resin 5.

In FIG. 3, a protrusion 4 is provided on the back surface of the commutator piece 2, and a recess 7 is formed in the axial direction of the protrusion 4. It should be noted that the recess 7 is formed in the riser 9 in the axial direction of the protrusion 4.
It may be provided on the side.

In such a structure, by turning on the switch of the commutator motor, the rotor and the mold commutator 1 integrated with the rotor rotate at a high speed of tens of thousands of revolutions per minute. Due to this high speed rotation, a centrifugal force is applied to the commutator 1 and vibration is generated in the commutator 1.
When the time during which the power is supplied in this state becomes long, the commutator 1 gradually becomes hot.

ON-OF of the switch of this commutator motor
By repeating F, the strength of the resin 5 holding the commutator piece 2 gradually decreases due to deterioration over time due to vibration and heat. Due to this deterioration, minute cracks are formed in the resin portion 5, and by repeated use of ON-OFF, these cracks gradually grow into large cracks. By further repeated use, the holding force of the resin 5 holding each commutator piece 2 reaches the limit, and the commutator piece 2 tends to scatter from the resin. However, since the reinforcing ring 3 is fitted in the concave portion 7 provided on the back surface of the commutator piece 2, and the ring 3 holds the protruding portion 4, the pop-out of the commutator piece 2 is suppressed.

The reinforcing ring 3 may be made of any material such as fiber, resin or new material as long as it is an insulator having both heat resistance and strength.

In the case of a small commutator or the like, the collar 8
Although a mold commutator that does not use is available, it goes without saying that the present invention also applies to such a commutator. Furthermore, in the case of a large commutator, the commutator piece 2
Although a molded commutator in which an insulating paper piece is arranged between the and the commutator piece 2 can be seen, the present invention is also applied to such a commutator.

[0016]

As described above, in the molded commutator of the present invention, a reinforcing ring made of an insulating material is inserted into the concave portion provided on the back surface of the commutator piece to integrally mold the molded commutator. The mold commutator can obtain strength equivalent to that of the formula and has stable quality.

Further, even if the resin loses the force for holding the commutator piece due to some abnormality, since the reinforcing ring holds the commutator piece, scattering can be prevented, and the mold commutator is highly safe. is there.

[0018]

[Brief description of the drawings]

FIG. 1 is a transverse cross-sectional view of a main part of a mold commutator according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view (cross-section AA) of a main part of a mold commutator according to an embodiment of the present invention.

FIG. 3 is a perspective view of a commutator piece according to an embodiment of the present invention.

[Explanation of symbols]

 1 ... Mold commutator 2 ... Commutator piece 3 ... Reinforcement ring 4 ... Projection part 5 ... Resin 6 ... Shaft hole 7・ ・ ・ ・ ・ Concave 8 ・ ・ ・ Color

Claims (1)

[Claims] 1. A commutator in which a large number of commutator pieces are juxtaposed in a cylindrical shape and integrally molded with resin, and the commutator pieces are fixed to each other, and a protrusion is provided on the back surface of each commutator piece. The invention is characterized in that a concave portion is formed in the axial direction of the protruding portion, a reinforcing ring made of an insulator is inserted into the concave portion, and the commutator pieces and the reinforcing ring are integrally molded with resin. Mold commutator.