JPH0984304A - Manufacturing method of ultra small diameter assembly type commutator - Google Patents

Abstract

(57) [Summary] [Purpose] To improve productivity and manufacture with high precision even with an extremely small diameter assembly commutator. A metal plate 11 is punched to form a connecting portion 12c on one end side, and a plurality of commutator pieces 3 connected to the connecting portion and slits 4 on the other end side and the commutator piece 3 are formed. A blanking step of forming the terminal portions 5 connected to each other in parallel, and a curling step of curling the connecting portion 12c and the commutator piece 3 into a cylindrical shape and bending the terminal portion 5 from the center to a substantially right angle in the radial direction. , The cylindrical connecting portion 12c and the commutator piece 3 are made of an electrically insulating synthetic resin, and the shaft hole 2 is formed at the center in the axial direction.
an assembling step of inserting the holder 2 having a formed therein, a mounting step of mounting a washer 6 having an electrical insulation property on the outer periphery of the commutator piece 3, and at least a connecting portion 12c is cut off while the washer 6 is mounted, and a slit 4 is formed. And a step of cutting the commutator piece 3 to be isolated via the.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a commutator for a small DC motor used for driving, for example, a portable electronic device, and more particularly to a method for manufacturing an assembly commutator having a very small diameter.

[0002]

2. Description of the Related Art Small motors are widely used in various kinds of equipment, and as miniaturization and miniaturization progresses, miniaturization of direct current motors used in the above equipment is also desired, and the diameter is 5 mm or less. DC motors have also appeared. Along with this, miniaturization of commutators used in microminiature motors is inevitably required.

Conventionally, two types of commutators of this type, an assembly type commutator and a mold type commutator, have been generally put to practical use. As shown in Japanese Unexamined Patent Publication No. 7-79546, the assembly type commutator is usually provided on the outer peripheral surface of a cylindrical synthetic resin holder having a large-diameter flange portion formed on one end side.
It is assembled by arranging a plurality of individually manufactured commutator pieces in a cylindrical shape with a minute gap so as to be electrically independent. After that, an insulating ring having electrical insulation is press-fitted onto the outer circumferences of these commutator pieces so as to abut the flange portion, and the commutator pieces are pressed against the outer circumference of the cylindrical portion of the holder and formed integrally with the commutator pieces. It is manufactured by sandwiching and fixing the formed terminal portion between the insulating ring and the flange portion.

The mold commutator is formed by cutting a cylindrical metal material such as copper into an appropriate size and press-punching the terminal to integrally project the terminal portion from one end side of the metal material. Bend and form at a substantially right angle. After that, a holder part made of an insulating synthetic resin is insert-molded with the cylindrical material so that the outer peripheral surface and the tip side of the terminal part are exposed. After that, in order to electrically separate the cylindrical metal material into a plurality in the circumferential direction, a slitting process is performed to put a plurality of slits in the axial direction up to the synthetic resin portion by a slicer,
This forms a commutator piece divided into a plurality of pieces. Further, a mold commutator is manufactured by performing final finishing.

[0005]

However, the above-mentioned conventional manufacturing method is suitable for the case where the diameter of the commutator is relatively large, but in the case of the commutator having a very small diameter of several mm, It has become apparent that the problem is virtually difficult to manufacture.
That is, in the assembly type commutator, normally, the step of arranging the individually manufactured commutator pieces in a cylindrical shape on the outer circumference of the cylindrical portion of the holder is manually performed. However, in the case of an assembly commutator with an extremely small diameter, the commutator piece itself has a very small size, which makes it difficult to work with fingers, and the gap (slit) between adjacent commutator pieces has a minute gap. Therefore, there is a problem that the dimensional accuracy is lowered and the rectifying function which is the original function of the commutator cannot be obtained. Further, even if an attempt is made to automate the assembly of the commutator pieces, it is extremely difficult to supply the individual commutator pieces to the automatic assembling machine by a simple and inexpensive means because the commutator pieces themselves have a very small size. There are also problems.

On the other hand, in the mold type commutator, it seems that a commutator having an extremely small diameter can be manufactured by minimizing the diameter of the cylindrical metal material. However,
In order to form an electrically independent commutator piece, it is necessary to slit not only a cylindrical metal material but also an axial slit to the holder portion by slitting. However, in the case of an extremely small diameter commutator, it is necessary to reduce the wall thickness of the holder as a matter of course. Therefore, when the slit is formed, the wall thickness of the holder must be further reduced, and the problem that the strength is remarkably lowered becomes clear. Therefore, when press-fitting into the rotating shaft of the motor,
Or, in the worst case such as disassembly or cracking due to vibration during operation, the mold type cannot be adopted for the above reasons. In particular, in a multipole commutator, a large number of slits are formed, so that the strength reduction becomes more remarkable.

In view of the above problems, the present invention intends to provide a method of manufacturing an extremely small diameter assembly type commutator which can improve the productivity even with an extremely small diameter and can be manufactured with high accuracy. It is a thing.

[0008]

According to another aspect of the present invention, there is provided a method for manufacturing a commutator having an extremely small diameter, wherein a metal plate is punched to form a connecting portion on one end side and the other end is connected to the connecting portion. A blank removing step of forming a plurality of commutator pieces and a terminal portion connected to the commutator piece in parallel through a slit on the side, and curling the connecting portion and the commutator piece into a cylindrical shape, and the terminal portion. A curling step of bending from the center to a substantially right angle in the radial direction, and forming a shaft hole in the center of the axial direction made of synthetic resin having electrical insulation inside the cylindrical connecting portion and commutator piece Assembling step of inserting the holder, mounting step of mounting an electrically insulating washer on the outer periphery of the commutator piece, cutting off at least the connecting portion with the washer mounted, It is characterized in that through the Tsu bets; and a cutting step of the isolated commutator segments.

In the method for manufacturing a commutator with a very small diameter according to claim 2, the holder is inserted into the connecting portion and the commutator piece,
The connection part is cut together with the holder by a cutting process.

In the method for manufacturing a commutator having an extremely small diameter according to a third aspect of the present invention, the holder is inserted into the commutator piece, and only the connecting portion is cut by the cutting step.

According to the method of manufacturing a commutator of the extremely small diameter as set forth in claims 1 to 3, since each commutator piece is previously connected by the connecting portion, the commutator piece has a minute size. It is now possible to assemble a large number of commutator pieces integrally and simultaneously with the holder, and have a diameter of 2 mm.
Even with a commutator with a very small diameter, the workability is greatly improved and the productivity is further improved. Further, by connecting the commutator pieces in advance by the connecting portion, the slit spacing between the commutator pieces can be made uniform with high accuracy even if the commutator has an extremely small diameter. Furthermore, according to the manufacturing method of claim 3, the waste of the material discarded by cutting can be suppressed to the minimum, and the cost can be reduced.

According to a fourth aspect of the method for manufacturing a commutator of the smallest diameter assembly type, after mounting a washer having electric insulation on the outer periphery of the commutator piece formed into a cylindrical shape by the curling process, the holder is attached to the commutator piece. It is characterized by having a mounting step of inserting it inside.

According to the method for manufacturing a commutator of the extremely small diameter as described in claim 4, when the washer is mounted after inserting the holders of the commutator pieces, the washer itself damages the surface of the commutator piece. However, the damage to the surface of the commutator piece can be eliminated by mounting the washer in advance.

According to the fifth aspect of the method for manufacturing an extremely small diameter assembly type commutator, a clad zone of a noble metal having good conductivity such as gold is formed at a position corresponding to a commutator piece of a metal plate made of copper or the like. It is characterized by that.

According to the manufacturing method of the extremely small diameter assembling commutator according to the fourth aspect, the expensive precious metal is used only in the portion which is in sliding contact with the brush when assembled in the motor, and the connection becomes an unnecessary portion. Since the part is an inexpensive metal, even if it is a high-performance commutator with an extremely small diameter, it is possible to minimize the cost increase.

According to a seventh aspect of the method of manufacturing an extremely small diameter assembly type commutator, the commutator pieces formed by punching a metal plate are three.
It is characterized by a large number of poles, which is more than the number of poles.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 show a first embodiment of a method of manufacturing an extremely small diameter assembly type commutator according to the present invention. As shown in FIG. 1, a cylindrical ultra-small diameter assembly commutator 1 includes a holder 2 made of a cylindrical synthetic resin having a large-diameter flange portion 2b formed on one end side, and a holder 2 formed on the outer peripheral surface of the holder 2. A plurality of commutator pieces 3 arranged in a cylindrical shape by providing slits 4 with minute intervals so that they are electrically independent of each other, and the commutator pieces 3 are attached to the outer circumference of these commutator pieces 3 by press fitting.
Is pressed against the outer circumference of the cylindrical portion of the holder 2, and is constituted by a washer 6 that abuts against the flange portion 2b and clamps and fixes the terminal portion 5 integrally formed with the commutator piece 3 between the flange portion 2b. Has been done.

Next, a method for manufacturing the extremely small diameter assembly type commutator 1 having such a configuration will be described in detail. First, as shown in FIG. 2, a commutator piece 3 which is a feature of the present invention is formed by punching an element body 12 from a metal plate 11 having good conductivity such as copper by a blank punching process using a progressive press machine. To be done.
The element body 12 includes, for example, three commutator pieces 3a1 and 3a2.
, 3a3, a slit 4 formed between these commutator pieces 3, a narrow terminal portion 5 integrally projecting downward from the commutator pieces 3a1, 3a2, 3a3 in the figure, and a plurality of terminals. A connecting portion 12c is formed for connecting the commutator pieces 3a1, 3a2, 3a3. In order to form the connecting portion 12c, the slit 4 extends up to near the upper side in the drawing.

The hoop material shown in the figure is suitable for the metal plate 11 in order to improve the productivity, but it may be a single material capable of being taken in large numbers. In addition, the metal plate 11 is thinner than a normal commutator so as to be an assembly type commutator having an extremely small diameter.
The thickness is preferably less than or equal to mm, but an appropriate thickness is selected according to the desired diameter of the commutator and the purpose of use. Further, the number of commutator pieces 2 may be three or more.

The element body 12 obtained by the blanking process described above is then subjected to the curling process shown in FIG. 3 to the connecting portion 12c and the commutator piece portions 3a1, 3a2, 3a.
Both 3 are curled into a cylindrical shape, and the terminal portion 5 is bent and formed substantially at a right angle from the center in the radial direction as shown in FIG. 2 (B). At this time, the gap between the commutator pieces 3a1 and 3a3 is formed to have substantially the same size as the gap of the slit 4.

The cylindrical body 12 thus curled into a cylindrical shape is assembled on the outer periphery of the holder 2 by the following assembly process. As shown in FIG. 4, the holder 2 is formed by molding an electrically insulating synthetic resin by molding, forms a shaft hole 2a at the center in the axial direction, and has a large diameter flange portion 2b and a commutator near the lower part of the drawing. Pieces 3a1, 3a2,
A cylindrical portion 2c for arranging 3a3 is integrally formed. The length of the cylindrical portion 2c is set to be substantially the same as the length of the connecting portion 12c and the commutator piece portions 3a1, 3a2, 3a3. Furthermore, on the upper surface of the flange portion 2b,
Three recesses 2d for installing the terminal portion 12c at a predetermined position are formed. Then, the curled connecting portion 12c of the body 12 and the commutator pieces 3a1, 3a2, 3
It is assembled by inserting a3 into the cylindrical portion 2c of the holder 2.

Thereafter, in the mounting step, as shown in FIG. 5, an annular washer 6 made of synthetic resin or the like having electric insulation is mounted on the outer periphery of the commutator pieces 3a1, 3a2, 3a3, and the washer 6 is mounted. Is brought into contact with the upper surface of the flange portion 2b of the holder 2. Since the inner diameter of the washer 6 is set to be substantially equal to the outer diameter of the commutator piece 3 as the final product, the washer 6 is inserted by press fitting when it is mounted. As a result, the commutator piece 3a
The recesses 2d formed in the upper surface of the flange portion 2b while closely contacting 1, 3a2, 3a3 with the cylindrical portion 2b of the holder 2
The terminal portion 5 installed in the is pressed and fixed.

Through the above steps, by mounting the washer 6 on the holder 2, the commutator pieces 3a1 and 3a2 are attached.
, 3a3 are fixed, the connecting portion 12c is cut off at the position of the cutting line 7 in the next cutting step. At this time, since the cylindrical portion 2c of the holder 2 is also formed to have a length reaching the connecting portion 12c, the tip end side of the cylindrical portion 2c is also cut off at the same time. As a result, the commutator pieces 3a1, 3a2, 3a
3 has three commutator pieces 3 electrically isolated from each other through the slits 4. After that, if necessary, the outer peripheral surface of the commutator piece 3 is appropriately finished, and the assembled commutator having an extremely small diameter according to the present invention is completed.

FIG. 6 shows a second embodiment of the present invention. That is, in the first embodiment, the cylindrical portion 2c of the holder 2 is formed to a length reaching the connecting portion 12c, and the tip side of the cylindrical portion 2c is cut off at the same time in the cutting process. In the embodiment, as shown in FIG. 6, the length of the cylindrical portion 2c of the holder 2 is set to be equal to or slightly shorter than the cutting line 7, and only the connecting portion 12c is cut off in the cutting process. There is. According to this embodiment, there is an effect that the waste of the material discarded by cutting is suppressed to the minimum and the cost can be reduced.

FIG. 7 shows a third embodiment of the present invention, in which a metal plate 21 having a noble metal cladding band 21d of good conductivity such as gold is formed at a position corresponding to the commutator piece 3. Is. That is, the clad band 21d is formed by joining two kinds of metals to a metal material made of copper or the like by pressing a separate metal plate or metal foil by pressure. In the present invention, when the commutator is assembled to a motor (not shown), a metal plate 21 in which a noble metal having good conductivity such as gold is clad only in a portion of the motor in sliding contact with the brush.
Is used.

As shown in FIG. 7, such a metal plate 21 is obtained by removing the commutator piece 23 from the metal plate 21 by a blank removing process using a progressive press machine as in the first embodiment. Stamped and formed. The element body 22 is composed of, for example, three commutator pieces 22a1, 22a2, 22a3, a slit 4 formed between the commutator piece portions 23, and the commutator pieces 22a1, 22a2, 22a3 integrated downward in the drawing. A narrow terminal portion 5 projectingly formed and a connecting portion 22c for connecting a plurality of commutator pieces 22a1, 22a2, 22a3 are formed. The clad band 21d is provided at a position corresponding to these commutator pieces, and the connecting part 22c and the terminal part 5 are made of only a copper material.

Next, by the curling process shown in FIG. 8, the connecting portion 22c and the commutator pieces 22a1, 22a2, 22a3 are both curled into a cylindrical shape so that the cladding band 21d becomes the outer peripheral surface. Further, as shown in FIG. 3, the terminal portion 5 is formed by bending it from the center in a radial direction at a substantially right angle, and thereafter, through the same steps as in the first embodiment described above, an assembly commutator having an extremely small diameter is formed. Manufactured. Therefore, although the connecting portion 22c is cut off at the position of the cutting line 7 in the cutting step, since the cladding band 21d does not exist at this position,
The inexpensive copper material is cut off, and the clad band 21d using an expensive metal material is also present as the final product as the commutator piece 3. As a result, the performance of the commutator having an extremely small diameter can be improved by forming the clad band 21d, but the cost increase can be suppressed to the minimum.

In each of the above-described embodiments, the number of commutator pieces is three as the commutator for three poles, but five poles and eight poles are used.
Needless to say, the present invention can be applied to a multi-pole commutator such as a pole and a 12-pole, and the present invention has a great effect as the number of poles is increased. In addition, the holder is made by outsert molding of synthetic resin etc. having insulating property on the rotating shaft of extremely small diameter,
The rotary shaft can be similarly used even if it is formed as thin as an insulating film by means of painting or the like, and is not limited to the examples of the present invention, and may be appropriately changed without departing from the present invention. It can be changed.

[0029]

As described above, in the present invention, since the commutator pieces are connected in advance by the connecting portion, even if the commutator pieces have a small size, a large number of commutator pieces are integrated. And at the same time, it can be assembled to the holder and the workability is greatly improved even with a commutator with an extremely small diameter of about 2 mm.
Productivity can be further improved. Further, by connecting the commutator pieces in advance by the connecting portion, the slit spacing between the commutator pieces can be made uniform with high accuracy even if the commutator has an extremely small diameter. These effects have 3 poles
The effect is further enhanced in a multi-pole commutator having more poles.

Further, according to the method of manufacturing a commutator having an extremely small diameter according to the fourth aspect, damage to the surface of the commutator piece caused by press-fitting the washer can be eliminated by mounting the washer in advance.

According to the manufacturing method of the extremely small diameter assembling commutator in claim 4, the expensive precious metal can be used only in the portion where the brush is slidably contacted when assembled in the motor, and the connecting portion becomes an unnecessary portion. Since it is an inexpensive metal, even if it is a high-performance extremely small diameter commutator that uses a precious metal having good conductivity, it is possible to minimize the cost increase.

[Brief description of drawings]

FIG. 1 is a half sectional view showing a completed state of an extremely small diameter assembly type commutator according to the present invention.

FIG. 2 is a plan view showing a blanking step according to the commutator manufacturing method of the present invention.

FIG. 3A is a half sectional view showing a curling step, and FIG. 3B is a bottom view.

FIG. 4 (A) is a half sectional view showing a holder,
(B) is a plan view.

FIG. 5 (A) is a half sectional view showing a mounting process,
(B) is a plan view.

FIG. 6 is a half sectional view showing a holder according to a second embodiment of the present invention.

FIG. 7 is a plan view showing a metal plate according to a third embodiment of the present invention.

FIG. 8 is a half sectional view showing the same curling step.

[Explanation of symbols]

 1 Miniature diameter assembly type commutator 2 Holder 3 Commutator piece 4 Slit 5 Terminal part 6 Washer 11 Metal plate 12c Connection part 17 Cutting line 21d Clad band

Claims (6)

[Claims] 1. A metal plate is punched to form a connecting portion on one end side, and is connected to the connecting portion and a plurality of commutator pieces and a plurality of commutator pieces are connected to the other end side through slits. A blank removing step of forming the terminal portions in parallel, a curling step of curling the connecting portion and the commutator piece in a cylindrical shape, and bending and forming the terminal portion in a radial direction from the center in a radial direction, and the cylinder. Assembling step of inserting a holder made of synthetic resin having electric insulation and having a shaft hole at the center in the axial direction into the inside of the connecting portion and the commutator piece which are formed into a shape, and electrically insulating the outer circumference of the commutator piece. And a cutting step of cutting off at least the connecting portion in the state where the washer is mounted to form a commutator piece isolated through the slit. Manufacturing method of extremely small diameter assembly type commutator. 2. The method for manufacturing an extremely small diameter assembly type commutator according to claim 1, wherein the holder is inserted into the connecting portion and the commutator piece, and the connecting portion is cut together with the holder in a cutting step. 3. The holder is inserted inside the commutator piece,
The method for manufacturing an extremely small diameter assembly type commutator according to claim 1, wherein only the connecting portion is cut in the cutting step. 4. The mounting step of inserting a holder into the commutator piece after mounting an electrically insulating washer on the outer circumference of the commutator piece formed into a cylindrical shape by the curling step. Manufacturing method of ultra small diameter assembly type commutator. 5. A commutator of a very small diameter assembly type commutator according to claim 1, wherein a clad band of a noble metal having good conductivity such as gold is formed at a position corresponding to the commutator piece of a metal plate made of copper or the like. Production method. 6. The method for manufacturing an extremely small diameter assembly type commutator according to claim 1, wherein the commutator piece formed by punching a metal plate is a multi-pole having three or more poles.