JPH07114540B2 - Rectifier for rotating electric machine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new structure of a rotary electric machine, and more particularly to a new structure of a rectifier for a rotary electric machine.

[0002]

2. Description of the Related Art A rotating electric machine has long been known as a device for converting electric energy into rotational energy and vice versa. Rotating electric machines can be roughly classified into AC electric machines and DC electric machines. Among the latter, like the direct winding electric machine and the shunt winding electric machine, since the invention was invented, the rotating electric machine was equipped with a rectifying device consisting of a commutator and a brush, and the fixed brush rotated through the commutator. Electric power is supplied to the child winding wire and the generated electric power is taken out.

In the structure of the commutator which constitutes the conventional rectifying device as described above, the contactor is arranged in a plurality of slits provided on the surface of the cylindrical insulating base attached to the rotary shaft, and the contactors are arranged. The rotor wound cotton is connected to, and a brush made of a carbon molded product is brought into contact with the surface of the commutator provided with a contactor so that power is supplied from the brush in the direction of the commutator or power is taken out from the commutator. I am.

[0004]

In the conventional rectifying device as described above, the surface of the commutator has a cylindrical shape and is smoothed, but the surface of the commutator is made of metal and an insulating material of carboxylic acid resin alternately. It has been placed in, and lacks lubricity. Therefore, even if the brush made of a carbon molded product that is in contact with it is self-lubricating, it has a disadvantage that it is rapidly worn. For this reason,
In the conventional type, the structure of the brush has been devised so that the brush is impregnated with lubricating oil to suppress wear, or the brush itself is made of porous carbon, and solid lubrication is performed in the pores inside. Attempts have been made to prevent the abrasion of the brush and the abrasion of the commutator surface in contact with it by embedding the agent or impregnating the pores with a liquid lubricant. With the configuration, it was not possible to prevent abrasion of the brush or commutator surface.

The present invention is intended to solve the above-mentioned conventional drawbacks, and an object thereof is to provide a rectifying device capable of reducing wear of the contact portion of the rectifying device of the rotating electric machine as much as possible. Is what you are trying to do.

[0006]

In order to achieve the above-mentioned object of the present invention, the present invention provides the inside of the slit provided on the side surface of the body of the dense ceramics formed in a cylindrical shape.
A commutator with a conductive part impregnated with metal in the pores of ceramics and a metal in the pores of a porous sintered body of magnesium phosphide, calcium phosphide and graphite.
A rectifying device for a rotating electric machine, comprising: an impregnated brush, wherein the brush is brought into contact with a contact surface of a body side surface of the rotating commutator.

[0007]

[Function] On the side surface of the body of the commutator, the insulating portion made of dense ceramics and the ceramic porous holes are filled with metal.
It has a contact surface in which impregnated conductive parts are alternately arranged, and the contact surface is impregnated with metal in the pores of a porous sintered body of calcium phosphide, magnesium phosphide and graphite. The broken brush slides into contact. Current flows between the brush and the conductive portion when the brush contacts the conductive portion, and when the brush is on the insulating portion, the current flow is stopped and rectification is performed.

[0008]

Next, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially cutaway perspective view showing an example of a DC motor equipped with a rectifying device according to the present invention. In FIG. 1, reference numeral 1 denotes a cylindrical housing made of soft iron, which also serves as a yoke. Inside the housing 1,
A rotor magnetic pole 9 composed of a permanent magnet is attached. Side covers 2 and 3 are provided on both sides of the housing 1. Ball bearings 4 and 5 are attached to the side covers 2 and 3, respectively. A rotary shaft 6 is rotatably supported by the ball bearings 4 and 5. 7 is a commutator, 8 is a rotor coil, 10 and 1
Reference numeral 1 is a brush that is in sliding contact with the surface of the commutator 7. These brushes 10 and 11 are brush holders 12 which also serve as terminals,
It is housed in the brush holder 12, and is pressed against the surface of the commutator 7 by the bias means housed in the brush holders 12, 13.

FIG. 2 shows a rotor assembly 1 in which a commutator 7 and a rotary magnetic pole 9 around which a rotor coil 8 is wound are mounted on a rotary shaft 6.
FIG. 4 is a front view showing No. 4. As shown in FIG. 3, the commutator 7 attached to the rotating shaft 6 is formed into a cylindrical shape, and is composed of a conductive portion A and an insulating portion B, and the side surface of the body that contacts the brushes 10 and 11 is smoothly polished. Has been done. The conductive portion A of the commutator 7 is made of porous silicon nitride (Si3
It is composed of a complex in which fine holes N4) are impregnated with copper or aluminum, and a conductive wire 15 for electrically connecting the conductive portion A and the rotor coil 8 is embedded inside. The insulating portion B is formed of dense silicon nitride (Si3N
It consists of 4).

Next, a method of forming the commutator 7 will be described. First, a product obtained by kneading silicon nitride powder and a binder with water,
For example, molding is carried out by the SIP method to prepare an intermediate molded product as described below. As shown in FIG. 4, this intermediate molded product has a shape having a portion C except for the conductive portion A, which is formed in a slit shape. This is sintered to form an insulating portion B made of dense silicon nitride. Then, a thin wire made of a fluororesin which is slightly thicker than the conductor 15 is arranged in the slit-shaped portion C, and 100 parts by weight of silicon nitride powder and 15 parts by weight of metallic titanium powder are placed in the slit-shaped portion C. The mixture is kneaded and kneaded with oil, and the resulting mixture is packed and sintered in a nitrogen atmosphere at a temperature of 1400 ° C. At this time, the fine wire made of fluororesin is vaporized and dispersed in a high temperature atmosphere. Therefore, a hole is formed in the portion where the thin line was present. Further, due to this sintering, fine pores having a porosity exceeding 20% are generated in the portion C.
Further, these fine holes are connected to each other. When the bond between the dense silicon nitride and the porous portion is weak, the dense silicon nitride portion and the porous portion are extremely strongly intimately contacted with each other by re-heat treatment in the air at 800 ° C. After this, the cylinder is immersed in the molten copper in the crucible. The porous body containing silicon nitride as a main component has extremely good wettability with respect to copper and aluminum, and the dissolved copper permeates into the fine pores by a capillary phenomenon. Then, a well-cooled copper wire is immediately inserted into the hole into which the fine fluorine resin wire has been inserted, and the entire cylindrical body is pulled up from the crucible filled with molten copper. The commutator 7 is completed by polishing the contact surface with the brush later.

Next, the details of the brushes 10 and 11 will be described. The brush of the present invention comprises a conductive portion of the commutator in fine pores of a porous body obtained by kneading calcium phosphide, magnesium phosphide (CaP2, MgP2) powder and graphite powder together with a binder and sintering the mixture. In the same manner as in A, copper is impregnated to form a brush. The coefficient of friction of a porous body obtained by sintering calcium phosphide (CaP2) powder , magnesium phosphide (MgP2) powder and graphite powder is extremely small, and in particular, the coefficient of friction with silicon nitride is 0.0.
The value is 2 to 0.04, which is almost the same as that of the fluid lubrication. Although not shown in FIGS. 1 and 5, the upper ends of the brushes 10 and 11 are provided with pigtails similar to those of a conventional carbon brush, and these brush holders 12 and 13 also serve as terminals. It is connected.

[0012]

As described in detail above, the present invention is
Inside the slit formed on the side surface of the cylindrical body of dense ceramics, a commutator provided with a conductive portion impregnated with metal in the pores of ceramics, calcium phosphide , phosphorus Since the porous sintered body of magnesium oxide and carbon has a brush impregnated with metal in the pores, and the brush is brought into contact with the contact surface of the body surface of the rotating commutator, liquid lubrication is performed. The commutator and the brush can be brought into sliding contact with a low friction coefficient without using an agent.
Therefore, in the rectifier of the rotary electric machine, the wear of the brush is extremely small compared to the conventional rotary electric machine,
Even the wear of the commutator surface can be reduced.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view showing an example of a DC motor equipped with a rectifying device according to the present invention.

FIG. 2 is a front view showing a rotor assembly.

FIG. 3 is a perspective view showing a part of a commutator and a brush.

FIG. 4 is a perspective view showing a semi-finished product of a commutator.

FIG. 5 is a front view showing a contact state between a commutator and a brush.

[Explanation of symbols]

 1 ... Housing 2 ... Side cover 3 ... Side cover 4 ... Ball bearing 5 ... Ball bearing 6 ... Rotating shaft 7 ... Commutator 8 ... Rotor coil 9 ... ..Rotor magnetic pole 10 ... Brush 11 ... Brush 12 ... Brush holder 13 ... Brush holder 14 ... Rotor assembly 15 ... Conducting wire A ... Conductive portion B ...・ Insulated part C ・ ・ ・ Slit-shaped part

Claims (4)

[Claims] 1. A commutator having a conductive portion, which is obtained by impregnating a metal in a porous ceramic hole, inside a slit provided on a side surface of a body of a dense ceramic having a cylindrical shape, Calcium phosphide, magnesium phosphide (CaP
2, MgP2) and a brush in which the pores of a porous sintered body of graphite are impregnated with metal, and the brush is brought into contact with the contact surface on the body side surface of the rotating commutator. Rectifier for rotating electric machine. 2. The rectifying device for a rotary electric machine according to claim 1, wherein the dense ceramics of the commutator is silicon nitride. 3. The rectifying device for a rotating electric machine according to claim 1, wherein the conductive portion of the commutator is a composite material in which the pores of porous ceramics are impregnated with a metal. 4. A rectifying device for a rotary electric machine according to claim 1, wherein a conductive wire is embedded in the conductive portion.