JP3359400B2 - Method of manufacturing commutator and rotary converter using the commutator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary converter such as an electric motor or a generator, and a method for manufacturing a commutator used therein .

[0002]

2. Description of the Related Art Electric motors are used in various home appliances such as vacuum cleaners, washing machines, dryers, fan heaters, juicers, mixers, etc., electric tools such as electric drills and grinders, and various other industrial machines. .

As shown in FIG. 7, a schematic structure of this electric motor is such that a field coil 15 is provided around the inside of a casing 17.
And a brush 16 for fixing the rotor 14 having the armature coil and the commutator 13 inside the field coil 15 and rotatably supporting the same, and supplying power to the commutator 13. Then, when electricity is supplied through the brush 16, the rotor 14 and the commutator 13 rotate by electromagnetic force, and rotational energy can be extracted from the shaft 18 connected to the rotor 14.

The structure shown in FIG. 7 can be used as a generator as it is.
A voltage can be generated between 6 and 16. That is,
The electric motor and the generator are both for converting electric energy and rotational energy to each other, and in the present invention, these are collectively called a rotational converter.

FIG. 6 shows the structure of only the commutator 13. As shown in FIG. 6, the commutator 13 has a plurality of commutator pieces 12 made of a copper rod on the side surface of an insulator 11 made of a cylindrical resin. Provisions were common. In addition, the rectifying piece 12
Is connected to a rotor 14 on the side of the small-diameter portion 12a to connect a current-carrying wire to each of the armature coils to the small-diameter portion 12a.

In order to manufacture the commutator 13, a ring-shaped copper plate having a shape in which the commutator pieces 12 are connected to each other is molded around a resin insulator 11, and then the ring-shaped copper plate is fixed to a predetermined shape. Cutting was performed in the axial direction at intervals and divided into a plurality of commutator pieces 12 as shown in FIG. that time,
In order to ensure electrical insulation between the commutator pieces 12, cutting to a resin insulator 11 deeper than the thickness of the ring-shaped copper plate has also been performed.

Japanese Utility Model Application Laid-Open No. 63-202162 discloses a resin insulator in which a ceramic insulating layer is formed on the inner peripheral side of the resin insulator.

[0008]

However, when the electric motor is rotated, the commutator 13 also rotates and slides with the brush 16 to generate heat. When the amount of heat generation increases, the resin-made insulator 11 becomes hot. There was a problem that it was easily deformed. Particularly, in recent years, a high output electric motor has been demanded, but the output of the electric motor itself cannot be increased due to the deformation of the resin insulator 11.

Therefore, it is conceivable that the insulator 11 is made of a ceramic material having excellent heat resistance. In this case, the insulator 11 made of ceramic and the commutator piece 1 made of copper are used.
2 was difficult to join. For example, a ceramic body is metallized, and a commutator piece 1 made of copper is formed by brazing.
However, it is difficult to increase the mounting position accuracy of the commutator pieces 12 by brazing, and in order to insulate the commutator pieces 12 from each other, metallizing is performed only at the joining points. And there is a problem that the manufacturing process becomes complicated.

[0010]

In view of the above, the present invention provides
Commutators that make up rotary converters such as electric motors and generators
As a manufacturing method, a plurality of grooves extending deep in the axial direction on the side
The formed ceramic cylindrical body and the groove of the cylindrical body
And a metal commutator piece having a locking part
The locking portion of the commutator piece was inserted into the groove of the cylindrical body.
By pressing in the radial direction in the state, the commutator pieces are locked.
Plastically deformed and fixed so that the part spreads in the groove.
is there.

[0011] Further, it is connected to the commutator manufactured as described above.
The rotation converter thus configured is rotatably arranged in a field coil .

[0012]

According to the present invention, by using ceramics as the insulator, the ceramics are not deformed even when the temperature becomes high during rotation, and the output of the rotary converter can be further increased.

Further, the commutator pieces made of metal such as copper are plastically deformed and fixed to the grooves of the ceramic insulator, so that the commutator pieces can be joined in a simple process with excellent positional accuracy. .

[0014]

Embodiments of the present invention will be described below.

As shown in FIG. 1, according to the manufacturing method of the present invention ,
The commutator 13 is formed by forming a cylindrical insulator 1 having a through hole 1b for mounting a shaft from ceramics, and having a plurality of grooves 1a in its side surface in the axial direction. The metal commutator piece 2 is plastically deformed and attached. The commutator piece 2 is a rod-shaped body, one end of which is a small-diameter portion 2a, and has a locking portion 2b that enters the groove 1a.

As shown in detail in FIG. 2, the mounting structure of the commutator piece 2 has a groove 1a provided on the side surface of the ceramic insulator 1, and the groove 1a has a widened shape. The portion 2b has two protrusions 2c.
Then, as shown in FIG. 3 (a), the locking portion 2 b of the commutator piece 2 is inserted into the groove 1 a of the insulator 1, and the commutator piece 2 is pressed in the radial direction of the insulator 1. , FIG.
If the commutator pieces 2 are plastically deformed as shown in FIG. 2B, the projections 2c are widened and both can be reliably locked.

At this time, if the positional accuracy of each groove 1a is previously formed with high accuracy, the commutator piece 2 is positioned with high accuracy. Further, the locking portion 2b of the commutator piece 2 is plastically deformed so as to spread in the groove 1a, and both are firmly fixed.

Incidentally, the commutator piece 2 is usually 22 to
The dimensions of the groove 1a in FIG. 2 are such that the width A of the inlet portion is 0.5 to 2 mm, the width B of the innermost portion is 0.6 to 2.3 mm, and the depth C is 0. What is necessary is just to set it as the range of 5-2 mm. The edges 1c of the grooves 1a are each a curved surface having a radius of curvature of about 0.1 to 2.0 mm to prevent chipping and cracking. Further, FIG.
As shown in (b), the crushing allowance D accompanying the plastic deformation of the commutator piece 2 due to the pressure may be in the range of 0.1 to 1.0 mm.

The commutator piece 2 after plastic deformation is made of an insulator 1
However, since there is a gap partially between the locking portion 2b and the groove 1a, the stress due to the difference in thermal expansion between the two can be absorbed.

Further, as shown in FIG. 4, the locking portion 2b of the commutator piece 2 is made to have a divergent shape, and is slid in the axial direction to be inserted into the groove 1a. It is also possible to use a device that is securely locked.

As the ceramics forming the insulator 1, various ceramics may be used as long as they are excellent in heat resistance and insulation properties, such as alumina, zirconia, and silicon nitride. For example, 90% or more, preferably 99% or more of Al ₂ O ₃ is contained as a main component, and the remainder is SiO ₂ , C
Alumina ceramics made of aO, MgO or the like is used. Alternatively, ZrO ₂ , which is a main component, contains Y ₂ O ₃ , CaO, MgO, or the like as a stabilizing agent, and the tetragonal phase is 80%.
% Or more may be used.

The commutator piece 2 may be made of any material as long as it is conductive and plastically deformable, but preferably has excellent wear resistance so as to withstand sliding with a brush. Usually, copper containing silver is used.

Next, a method for manufacturing the commutator 13 of the present invention will be described. First, a ceramic insulator 1 having a plurality of grooves 1a as shown in FIG. 1 is manufactured in advance. This insulator 1
Is, by pressing or extruding the specified raw material powder,
It can be obtained by molding in advance into a cylindrical shape having a groove 1a, or cutting the groove 1a after forming into a cylindrical shape, and then firing the obtained molded body under predetermined conditions.

On the other hand, a commutator piece 2 having a sectional shape as shown in FIG. 2 is formed of a metal such as copper. This may be manufactured by drawing using a die, casting, or the like.

Then, while the commutator piece 2 is inserted into the groove 1a of the insulator 1, pressure is applied from the outside to plastically deform the commutator piece 2. This pressing can be carried out by rolling or pressing. For example, as shown in FIG. 5A, the rolling is performed by inserting the insulator 1 into which the commutator pieces 2 are inserted into two rollers 20 from both sides. In this method, both rollers 20 are rotated while being sandwiched between the rollers 20, and the commutator pieces 2 are sent out in the axial direction of the rollers 20 while rotating the insulator 1. As shown in FIG. 5 (b), the pressing is performed by pressing the insulator 1 in which each commutator piece 2 is inserted between the pressing members 21 and 21 so that the two commutator pieces are pressed. 2 is plastically deformed, and then the insulator 1 is slightly rotated to apply the same pressure to plastically deform all the commutator pieces 2.

When the thus obtained commutator 13 is incorporated in an electric motor as an example of a rotary converter, the small diameter portion 2a of the commutator piece 2 of the commutator 13 as shown in FIG.
The rotor 14 is joined to the side, and the conducting wire to the armature coil provided on the rotor 14 is connected to the small-diameter portion 2 a of the commutator piece 2.
The shaft 18 is located at the center between the rotor 14 and the commutator 13.
May be rotatably disposed in a casing 17 provided with a field coil 15 and a brush 16 for supplying power to the commutator 13 may be provided.

When a voltage is applied through the brush 16, the commutator 13 and the rotor 14 rotate. At this time, the commutator 13 generates heat because it slides with the brush 16, but since the insulator 1 is made of ceramics, there is no risk of deformation and the output of the electric motor can be increased. In addition, since each commutator piece 2 is positioned with high accuracy, stable rotation performance without unevenness can be obtained.

Here, as an embodiment of the present invention, the insulator 1 is referred to as A
l formed by ₂ O ₃ content of 99% of alumina ceramics, the commutator segments 2 having a shape shown in FIG. 2 is formed of copper containing silver, is plastically deformed to 22 sheets of commutator segments 2 in press pressurization The commutator 13 was prototyped by fixing it to the groove 1a. On the other hand, as a comparative example, a commutator 13 was prepared by molding a commutator piece 12 on a conventional resinous insulator 11. The commutator 13 had an outer diameter of 20 mm and a length of 18 mm. After incorporating each commutator 13 into an electric motor and rotating it at a rotation speed of 10,000 revolutions / minute for 100 hours, a change in the outer diameter of the commutator 13 due to thermal expansion was examined. .

[0029]

[Table 1]

The results clearly show that the commutator 13 of the present invention hardly undergoes thermal deformation, whereas the commutator 13 of the present invention has an outer diameter larger than 1 mm in the conventional resin commutator 13.

Further, during the rotation test, the commutator 13 of the present invention has sufficient durability against centrifugal force during rotation and sliding with the brush 16 without the commutator piece 2 coming off. Showed sex.

In the above embodiment, an example is shown in which the commutator of the present invention is applied to an electric motor.

[0033]

As described above, according to the manufacturing method of the present invention, the ceramic having a plurality of grooves extending in the axial direction on the side surface is formed.
A cylindrical body made of a mix and a member inserted into a groove of the cylindrical body;
A metal commutator piece having a stop,
Radial direction with locking part of commutator piece inserted in groove of body
By pressing, the locking portion of the commutator piece spreads in the groove.
Since the insulator of the commutator is made of ceramics by being plastically deformed and fixed as described above, thermal deformation can be prevented even if the temperature becomes high due to the heat generated during rotation of the motor. Further, since the commutator pieces are plastically deformed and fixed, the commutator pieces can be firmly and accurately fixed with a simple operation, and separation during rotation can be prevented.

Further, the commutator manufactured according to the present invention is connected to the commutator.
The rotor that is connected is rotatably arranged in the field coil.
Since the commutator is not thermally deformed , the rotation converter can improve the output. In addition, since the position accuracy of the commutator pieces is high, stable rotation performance with less unevenness can be obtained.

[Brief description of the drawings]

1A is a partially cutaway side view showing a commutator manufactured according to the present invention, and FIG. 1B is a sectional view taken along line XX in FIG. 1A.

FIG. 2 is a partially enlarged cross-sectional view for explaining a mounting structure of a commutator piece in a commutator manufactured according to the present invention.

FIGS. 3A and 3B are partial cross-sectional views for explaining a method of attaching a commutator piece in a commutator manufactured according to the present invention.

FIGS. 4A and 4B are partial cross-sectional views illustrating another example of a commutator manufactured according to the present invention and illustrating a method of attaching a commutator piece.

FIGS. 5A and 5B are diagrams illustrating a method for manufacturing a commutator according to the present invention.

FIG. 6 (a) is a partially cutaway side view showing a conventional commutator, and FIG. 6 (b) is a sectional view taken along line YY in FIG. 6 (a).

FIG. 7 is a schematic sectional view showing the structure of an electric motor as an example of a rotary converter.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H02K 13/00-13/14 H01R 39/00-39/64 H01R 43/027-43/28

Claims (2)

(57) [Claims] 1. A plurality of grooves extending in the axial direction on the side surface.
Metal rectifier having a ceramic cylindrical body and a locking portion inserted into a groove of the cylindrical body.
State consists child piece was inserted the locking portion of the commutator segments in the groove of the cylindrical body
By pressurizing in the radial direction, the locking portion of the commutator piece
Characterized by being plastically deformed and fixed so as to spread in the groove
Method for manufacturing a commutator. 2. A rotary converter in which a rotor connected to the commutator manufactured by the method according to claim 1 is rotatably arranged in a field coil.