JPH0728514B2 - Method for manufacturing commutator of rotating armature - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a commutator for a rotary armature, and more specifically, forming a fine groove for dividing the commutator into commutator pieces without cutting. It is a thing.

2. Description of the Related Art A commutator coupled to a rotating armature has a plurality of axial fine grooves at intervals in the circumferential direction on the outer peripheral surface of a copper ring having an insulating resin portion as a shaft fitting portion. It is provided and is divided into commutator pieces insulated from each other by the narrow groove.

Conventionally, the fine groove for dividing the commutator into the commutator pieces is formed by performing a fine groove cutting process on the outer peripheral surface of the copper ring using a dedicated cutter such as a metal saw. The fine groove cutting process is performed by using the commutator alone after molding the insulating resin portion,
It may be performed after connecting the commutator to the rotating armature, but in any case, the cutter comes into contact with the resin portion during the fine groove cutting process, so that the insulating resin portion is easily broken, In the case of a small commutator, it may cause cracks. In addition, the cutter side is liable to cause a decrease in sharpness (life) and a damage. Further, it is necessary to position the cutting location and it is necessary to prevent variations in cutting, which increases the management conditions for processing. In addition, if the cutting dust bites into the fine groove portion and remains, it may cause a layer failure.

OBJECT OF THE INVENTION The present invention solves various problems caused by the fine groove cutting process by eliminating the fine groove cutting process.

In order to achieve the above-mentioned object, in the present invention, in a method for manufacturing a commutator of a rotating armature, a copper ring is cut into a predetermined length, a flange is formed at one end, and any commutator segment is divided. From the outer peripheral surface of the copper ring having a hollow groove portion in the inner peripheral portion of the copper ring by performing the squeeze processing from the inner diameter side of the copper ring using the narrow groove punch of the mold formed corresponding to the number. A plurality of protruding protrusions are provided on the circumferential surface of the copper ring, and the copper ring is arranged in an insulating resin molding die, and an outer hemisphere portion is provided at the entrance of the narrow groove portion of each protrusion of the copper ring. The inlet of the narrow groove portion is closed, and the needle pin is arranged so that the inner hemisphere portion projects from the inner peripheral surface of the copper ring, and the inner peripheral portion of the copper ring excluding the narrow groove portion is filled with resin. The insulating resin part is molded, and the insulating resin molding die and the needle-shaped pin are molded. After removing from the copper ring, the outer peripheral surface of the copper ring is turned to a finished dimension, and the copper ring is divided into a plurality of commutator pieces by the narrow groove portion of the cavity, and a commutator for a rotating armature. The present invention provides a method for manufacturing the same.

Examples Hereinafter, the present invention will be described in detail with reference to Examples shown in the drawings. The commutator of this embodiment has five commutator pieces.

FIG. 1 shows a copper ring 1 serving as a commutator piece, which is obtained by cutting a copper pipe (not shown) into a predetermined size.
The flange 1a is formed at one end thereof.

After the copper ring 1 is formed, as shown in FIG. 2, a copper punch (not shown) having five fine groove punches corresponding to the number of commutator pieces to be formed is used to form a copper ring. A press is applied from the inner diameter side of 1 using a press, and a protrusion 3 having a narrow groove portion 2 therein is bulged from an outer peripheral surface 4 of the copper ring 1 to be shaped. These five protrusions 3 project in parallel from the outer peripheral surface 4 along the axial direction at regular intervals in the circumferential direction,
The inlet 2a side of the narrow groove portion 2 in the projection 3 communicates with the inner peripheral space 5 of the copper ring 1, and the tip side 2b is located at a position protruding from the outer peripheral surface 4.

After the projection 3 having the narrow groove portion 2 is processed, a molding process described later with reference to FIGS. 5 and 6 is performed. In the molding die 6, a shaft fitting shaft hole is formed. At a predetermined position on the circumference around the inner diameter molding shaft 7, 5
The needle pins 8 of the book are installed, and these needle pins 8 are located inward of the entrance of the projection fitting recess 15 formed on the mold surface of the mold.

As shown in FIG. 3, the copper ring 1 is placed in the molding die 6 described above.
When the projections 3 of the copper ring 1 are fitted into the recesses 15 of the die 6, the outer hemisphere portion 8a of the needle pin 8 is fitted into the narrow groove entrance 2a of each projection 3 and the entrance 2a is inserted. It has been cut off.

When the copper ring 1 is set in the mold 6 as described above, the mold is clamped, and the insulating resin is injected, the resin is filled in the inner peripheral space 5 of the copper ring 1, and the inner periphery of the copper ring 1 is filled. An insulating resin portion 10 having a shaft fitting shaft hole 9 is integrally molded in the shaft core portion while being fixed to the surface. At this time, the inlet 2a does not flow into the narrow groove portion 2 in the protrusion 3 because the inlet 2a is blocked by the needle pin 8. As the resin to be filled, a phenol resin is used, and the mold temperature is set to 180 ° C. to 190 ° C. and held for 3 to 5 minutes.

After the resin molding, the copper ring 1 to which the insulating resin portion 10 is integrally fixed is released from the mold 6, and the needle pin 8 installed in the mold 6 is also connected to the insulating resin portion 10 from inside the copper ring 1. Separate and leave. In this way, the narrow groove portion 2 in the projection 3 becomes a hollow portion, and the resin portion on the inlet side of the hollow portion also has the inner hemispherical portion 8b of the needle pin 8 protruding toward the space 5 side. The resin molding is completed in the state in which the concave portion 10a is depressed. As described above, in this embodiment, the depth of the narrow groove portion 2 is t1, and the copper ring 1 that constitutes the commutator piece 12 as described later.
Deeper than the thickness t2.

Then, as shown in FIG. 4, on the outer peripheral surface of the copper ring 1,
When the conventional outer peripheral turning with the outer diameter as the finishing dimension is performed, the projection 3 is cut and the narrow groove portion 2 of the cavity is formed on the outer peripheral surface 4.
Appears in. A commutator piece having an outer peripheral surface 4 of 5 pieces due to the narrow groove portion 2.
Divided into 12, the commutator pieces 12 are held by the insulating resin portion 10 and completed as a commutator. When turning, the narrow groove 2
Since the resin portion 10a at the groove bottom is recessed from the inner peripheral surface of the copper ring 1, the turning blade never contacts the resin portion.

5 and 6 show an example of a mold 6 for resin molding shown in FIG. 3, wherein the mold 6 is an upper mold 20, a middle mold 21, and a lower mold.
It consists of 22 three types. The upper mold 20 has an inner diameter molding shaft 7
A needle pin holding shaft 23 is press-fitted around it at a predetermined interval, and the base side of the needle pin 8 made of a spring material such as a piano wire is fitted and held on the holding shaft 23. The middle mold 21 is provided with a mold hole 24 into which the copper ring 1 is fitted, and the above-mentioned projection fitting recesses 15 are provided at intervals on the mold surface of the mold hole 24. Further, the middle mold 21 is provided with a molding material supply passage 25 and the passage.
Gate that branches from 25 and supplies molding material to each mold hole 24
26, and a molding material discharge passage 27 for discharging the molding material overflowing from each mold hole 24. A positioning shaft 28 for positioning the spherical tip of the needle pin 8 is press-fitted into the lower mold 22.

In the die 6 described above, the copper ring 1 is fitted in the die hole 24 of the middle die 21, and in this state, the die 20, 21, 22 is positioned by the positioning pin 30.
Clamp the mold with. At this time, the needle pin 8 is set at the inlet 2a of the narrow groove portion 2 of the copper ring 1, and at this time, a slight gap is provided between the inlet 2a and the pin 8. This is to allow a slight margin in consideration of the positional error between the copper ring 1 and the needle-shaped pin 8, and after filling the molding material, the needle-shaped pin 8 made of a spring material is curved due to the internal pressure, Narrow groove 2
The entrance 2a is set to exactly close. In this way, by blocking the inside of the narrow groove portion 2 with the pin 8, the inside of the narrow groove portion 2 is not filled with the molding material, and the copper ring 1
Molding is performed in which the molding material is filled only in the inner peripheral space 5. At that time, mold the copper ring 1
In order to fill the entire space of the inner space 5, it is necessary to flow a little extra mold material from the supply passage 25. Therefore, the above-mentioned discharge passage 27 is formed to discharge the overflowed mold material, The mold material overflowing from the discharge passage 27 is discharged.

In FIG. 6, the upper two molding material filling examples show the state in which the copper ring 1 is set in the mold, and the lower two examples show the state before the copper ring 1 is set. There is. Generally, as the rotor rotates, the commutator piece slides on the brush pressed by the commutator. However, in the commutator according to the manufacturing method of the present invention, the space between the commutator pieces 12 is formed by the narrow groove portion 2 of the cavity. Since it is separated, only the commutator piece 12 contacts the brush, and the insulating resin portion 10 does not contact the brush. Therefore, the insulating resin portion 10 does not wear due to contact with the brush, and the insulating resin powder generated by this wear does not cause contact failure on the commutator piece 12.

Further, in the commutator manufactured by the manufacturing method of the present invention, since the depth t1 of the narrow groove portion 2 is deeper than the thickness t2 of the commutator piece 12 as described above, the brush is worn due to contact with the commutator piece 12. Also, the brush powder generated by this abrasion is stored in the recess 10a formed in the insulating resin portion 10, and the brush powder causes the commutator piece 12 to move.
There is no short circuit between them.

EFFECTS OF THE INVENTION As is apparent from the above description, according to the manufacturing method of the present invention, since the fine groove portion is formed by press shaping in the copper ring state before resin molding, the outer diameter is finished after resin molding. It can be separated into commutator pieces simply by performing size and peripheral turning. Therefore, it is possible to eliminate the need for the fine groove cutting process after resin molding, which is conventionally required, and it is possible to reduce the number of processing steps and to eliminate the defects caused by the fine groove cutting process. That is, it is possible to prevent the destruction of the resin and the damage of the cutter due to the contact between the cutting cutter and the resin, and the pin is set in advance in the mold for positioning the narrow groove position.
Since it is only necessary to fit the projection of the copper ring to the projection fitting recess of the mold surface, it is possible to obtain various effects such as the need for conventional positioning and the elimination of narrow groove variations. is there.

[Brief description of drawings]

1 (A) and (B) show a copper ring state, (A) is a front view (B) is a perspective view, and FIGS. 2 (A) and (B) are states in which projections having fine groove portions are formed on the copper ring. (A) is a front view (B) is a perspective view, FIG. 3 (A) and (B) is a resin molding state, (A) is a sectional view (B) is a perspective view, and FIG. 4 (A).
(B) shows the outer peripheral turning processing state (A) is a front view (B)
Is a perspective view, FIG. 5 is a sectional view of a mold for molding, and FIG.
The drawing is a sectional view taken along the line AA of FIG. 1 ... Copper ring, 2 ... Fine groove part, 3 ... Protrusion, 4 ... Outer peripheral surface, 5 ... Inner peripheral space, 6 ... Mold, 8 ... Needle pin, 10 ... Insulating resin part

Claims (1)

[Claims] 1. A method of manufacturing a commutator for a rotating armature, wherein a copper ring is cut into a predetermined length and a flange is formed at one end thereof, and a thin die of a mold formed corresponding to an arbitrary number of divided commutator pieces. The copper ring is punched from the inner diameter side by using a groove punch, and a protrusion protruding from the outer peripheral surface of the copper ring is formed on the inner peripheral surface of the copper ring. A plurality of protrusions, and the copper ring is arranged in an insulating resin molding die, and an outer hemisphere portion closes the inlet of the narrow groove portion at the inlet of the narrow groove portion of each protrusion of the copper ring, and The needle pin is arranged so that the inner hemisphere part protrudes from the inner peripheral surface of the steel ring, and the inner peripheral part of the steel ring excluding the narrow groove part is filled with resin to form an insulating resin part, After separating the resin molding die and the needle pin from the copper ring, And turning on the dimensions finishing the surface, method of manufacturing the commutator of a rotating armature of the copper ring, characterized in that into a plurality of commutator segments by narrow groove of the cavity.