JPS62285642A - Machining of commutator for revolving - Google Patents

Abstract

PURPOSE:To facilitate manufacture by a method wherein a copper ring is drawing-worked by a press, etc., from the inside of the copper ring by a working punch with projections in the same number as commutator bars, grooves are formed on the inside and projections on the outside, a resin is injected and the copper ring iq polished from the outside. CONSTITUTION:A copper ring 1 is cut in predetermined length, and a flange 1a is shaped at one end of the bopper ring. A working punch with projections in the same number (five in the figure) as commutator bars is inserted into the ring 1, and the ring is drawing-worked by employing a press, thus forming five grooves 2 on the inside and five projections 2 on the outside. Acicular pins 8 are brought into contact with inlets 2a in the grooves 2, the ring 1 is set into a mold 6 with recessed sections 15 corresponding to the projections 3 and a cylindrical section 7 corresponding to an inside-diameter molding shaft, and a resin 10 is injected. The resin cures, the ring 1 is taken out of the mold 6, the pins 8 are removed, and the ring 1 is polished from the outer circumferential section of the ring 1 to expose the grooves 2, thus shaping five commutator bars 12. Accordingly, positioning is facilitated, and dispersion is eliminated and productivity can be improved.

Description

[Detailed Description of the Invention] The present invention relates to a method for manufacturing a commutator for a rotating armature, and more specifically, the present invention relates to a method for manufacturing a commutator for a rotating armature, and more specifically, the invention relates to a method for manufacturing a commutator for a rotating armature. It is something that forms.

Conventional technology A commutator connected to a rotating armature has a plurality of narrow axial grooves spaced apart in the circumferential direction on the outer circumferential surface of a copper ring with an insulating resin part inside, which serves as the shaft fitting part. The structure is such that the commutator pieces are divided into commutator pieces that are insulated from each other by the narrow grooves.

The narrow grooves that divide the commutator into commutator pieces have conventionally been formed by cutting the outer peripheral surface of the copper ring into narrow grooves using a special cutter such as a metal saw.

The narrow groove cutting process may be performed on the commutator alone after molding the insulating resin part, or may be performed after the commutator is combined with the rotary armature, but in either case, the fine groove cutting process is During cutting, the cutter comes into contact with the resin part, which tends to cause damage to the insulating resin part, and may even cause cracks, especially in the case of a small commutator. In addition, the cutting quality (life) is likely to decrease and breakage may occur on the cutter side as well. Furthermore, it is necessary to position the cutting location, and it is also necessary to prevent variations in cutting, which increases the number of control conditions for processing. In addition, if chips from cutting were stuck in the narrow grooves and remained, this could lead to layer defects.

The present invention solves the various problems caused by the above-mentioned narrow groove cutting process by eliminating the need for the narrow groove cutting process.

In order to achieve the above-mentioned object, in the present invention, narrow grooves for insulating between the commutator pieces are formed during press forming in the copper ring state, and after resin molding, the grooves are formed in a conventional manner. This makes it possible to manufacture a commutator separated into commutator pieces by simply performing outer diameter finishing cutting, thereby eliminating the need for narrow groove cutting.

Specifically, in the process of manufacturing commutators for rotating armatures, a copper ring is cut to a predetermined length, a flange is formed at one end, and then a thin groove punch suitable for the desired number of commutator pieces is used to cut the copper ring into a predetermined length. After applying a stamping process using a press or the like from the inner diameter side of the copper ring, protrusions with thin grooves inside the ring are placed at predetermined intervals in the circumferential direction on the outer periphery of the ring, protruding parallel to the axial direction, and then insulating resin molding is performed. In the mold, a needle pin is set at the entrance of the narrow groove of each protrusion of the steel ring so as to block the entrance, and then resin molding is performed, and the inner peripheral space of the ring is filled with resin, and the inside of the narrow groove is filled with resin. After the resin was molded, the resin was removed from the mold and the pin, and the narrow groove was taken out as a hollow part. Cut the protrusion to represent the narrow groove,
The present invention provides a method for machining a commutator for a rotating armature, characterized in that the commutator is divided into a plurality of commutator pieces by the narrow grooves.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to embodiments shown in the drawings. The commutator of this embodiment has five commutator pieces.

FIG. 1 shows a copper ring l that becomes a commutator piece, and the copper ring l is cut into a predetermined size from a copper vibe (not shown).
A flange la is formed at one end thereof.

After forming the above-mentioned steel ring l, as shown in Fig. 2, using a general punch (not shown) equipped with five slotted punches corresponding to the number of commutator pieces to be formed, Ironing is performed using a press from the inner diameter side of the copper ring t, and the protrusion 3 having the narrow groove portion 2 inside is shaped so as to bulge out from the outer circumferential surface 4 of the copper ring t.

These five protrusions 3 protrude in parallel along the axial direction from the outer circumferential surface 4 at regular intervals in the circumferential direction, and the population 2a side of the narrow groove 2 in the protrusions 3 is located at a position protruding from the inner surface 4 of the copper ring l. It is in.

After processing the protrusion 3 having the narrow groove portion 2, molding, which will be described later with reference to FIG. 5 and FIG. 5 in advance at a predetermined position on the circumference around the inner diameter molding shaft 7.
Acrylic needle pins 8 are installed, and these needle pins 8 are located inside the entrance side of the protrusion fitting recess 15 formed on the mold surface of the mold.

As shown in FIG.
When each protrusion 3 of the copper ring l is inserted into each recess 15 of the mold 6, the outer hemisphere 8a of the needle pin 8 is fitted into the narrow groove part 2a of each protrusion 3, and the outer hemisphere 8a of the needle pin 8 is fitted into the groove 2a of each protrusion 3. is in a state where it is blocked.

When the copper ring l is set in the mold 6 as described above and the mold is clamped, and the insulating resin is injected, the resin is filled into the inner circumferential space 5 of the copper ring I, and the inner circumference of the copper ring l is filled with the resin. An insulating resin part IO, which is fixed to the surface and has a shaft hole 9 for fitting a shaft in the shaft core part, is integrally formed. 2a is blocked, so it does not flow in. A phenol resin is used as the resin to be filled, and the mold temperature is maintained at 180° C. to 190° C. for 3 to 5 minutes.

After the above-mentioned resin molding, when the copper ring 1 with the insulating resin part lO fixed to it is removed from the mold 6, the needle pin 8 installed in the mold 6 also connects with the insulating resin part IO from inside the copper ring l. Separate and leave. In this way, the narrow groove part 2 in the protrusion 3 becomes a hollow part, and the resin part on the entrance side of the hollow part also has a hemispherical shape because the inner hemispherical part 8b of the needle pin 8 protrudes toward the space 5 side. The resin molding is completed in a state where the recessed portion 10a is formed.

Next, as shown in FIG. 4, on the outer peripheral surface of the copper ring l,
When the conventional outer circumferential turning is performed with the outer diameter as the finished dimension, the protrusion 3 is cut and the narrow groove 2 in the cavity is formed on the outer circumferential surface 4.
It appears in The outer circumferential surface 4 is divided into five commutator pieces 12 by the narrow groove part 2, and these commutator pieces 12 are connected to the insulating resin part I.
It is held at O and completes as a commutator. Incidentally, during turning, since the resin part 10a at the bottom of the narrow groove part 2 is in a position recessed from the inner peripheral surface of the copper ring l, the turning blade never comes into contact with the resin part.

5 and 6 show an example of a mold 6 for performing resin molding shown in FIG. 3 above, and the mold 6 includes an upper mold 20, a middle mold 211
It consists of three molds including a lower mold 22. The upper die 20 is press-fitted with an inner diameter molding shaft 7 and a needle pin holding shaft 23 at a predetermined interval around the shaft, and the holding shaft 23 has a base of a needle pin 8 made of a springy material such as piano wire. It is held in place by inserting the sides. The medium mold 21 is provided with a mold hole 24 into which the copper ring l is fitted,
The above-mentioned protrusion-fitting recesses 15 are provided at intervals on the mold surface of the mold cavity 24. Further, the middle mold 21 is provided with a mold material supply passage 25 and a gate 26 branching from the passage 25 to supply mold material to each mold cavity 24, and for discharging mold material overflowing from each mold cavity 24. A mold material discharge passage 27 is provided. The lower mold 22 has a positioning shaft 2 on which the spherical tip of the needle pin 8 is positioned.
8 is press-fitted.

In the mold 6 described above, the copper ring 1 is fitted into the mold hole 24 of the middle mold 21, and in this state, the molds 20, 21, and 22 are clamped with the positioning pins 30. At this time, the needle-like pin 8 is set at the entrance 2a of the narrow groove 2 of the copper ring 1, but at this time, some gap is left between the entrance 2a and the pin 8. This is to take into account the positional error between the copper ring 1 and the needle pin 8 and to provide a little margin. After filling the mold material, the needle pin 8 made of a springy material will curve due to the internal pressure. It is set so as to perfectly close the entrance 2a of the narrow groove portion 2. In this way, by blocking the inside of the narrow groove part 2 with the pin 8, the molding material is not filled in the narrow groove part 2, and only the inner peripheral space 5 of the copper ring l is filled with the molding material. will be carried out. At that time, in order to fill the entire space 5 in the copper ring 1 with the molding material, it is necessary to flow a little extra molding material from the supply passage 25, and therefore, in order to discharge the overflowing molding material, The above-mentioned discharge passage 27 is formed,
The overflowing mold material is being discharged from the discharge passage 27.

In addition, in FIG. 6, the upper two examples of mold material filling 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 l is set. There is.

Effects of the Invention As is clear from the above explanation, according to the manufacturing method of the present invention, the narrow groove portion is formed by press shaping in the copper ring state before resin molding, so the outer diameter is finished after resin molding. It can be separated into commutator pieces by simply adjusting the dimensions and turning the outer circumference. Therefore, the cutting of narrow grooves after resin molding, which was conventionally required, can be eliminated, the number of processing steps can be reduced, and the drawbacks caused by the cutting of narrow grooves can be eliminated. In other words, it is possible to prevent damage to the resin and the cutter due to contact between the cutting force and the resin, and the position of the narrow groove is determined by setting the pin in the mold with the front side. into the recess for fitting the protrusion.

Since it is only necessary to fit the protrusions of the copper ring, there is no need for positioning as in the conventional method, and there are various effects such as eliminating variations in the narrow grooves.

[Brief explanation of the drawing]

Figures 1 (A) and (B) show the state of the copper ring, A) is a front view, (B) is a perspective view, and Figure 2 (AXB) shows the state in which the copper ring has been shaped into a protrusion with a narrow groove. A) is a front view (
B) is a perspective view, Figure 3 (AXB) shows the state of resin molding, A) is a sectional view (B) is a perspective view, and Figures 4 (A) and (B) show the state of outer circumference turning. is a front view (B) is a perspective view, and FIG. 5 is a cross-sectional view of the molding die.
FIG. 6 is a sectional view taken along line A--A in FIG. 5. l...Copper ring 2...Narrow groove 3...Protrusion 4...Outer periphery 5...Inner periphery space 6...Mold 8...Needle pin 10...Insulating resin part

Claims (1)

[Claims] (1) In the process of manufacturing commutators for rotating armatures,
After cutting the copper ring to a predetermined length and forming a flange on one end, the copper ring is pressed from the inner diameter side using a slotted punch that matches the desired number of commutator segment divisions. After protruding in parallel along the axial direction with protrusions having narrow grooves inside at predetermined intervals in the circumferential direction on the outer periphery, the inlets of the narrow grooves of each protrusion of the copper ring are placed in an insulating resin mold. After setting a needle pin to block the inlet, resin molding is performed.The inner circumferential space of the ring is filled with resin and the inside of the narrow groove is blocked from flowing in. After resin molding, the mold and After detaching from the pin and taking out the narrow groove part as a hollow part, the outer circumferential surface of the copper ring is lathed to the finished dimensions, and the protrusion protruding from the outer circumferential surface is cut to represent the narrow groove part,
A method for processing a commutator for a rotating armature, characterized in that the commutator is divided into a plurality of commutator pieces by the narrow grooves.