JPH07274448A - High-speed dc motor-generator - Google Patents

Abstract

PURPOSE:To provide a high-speed DC motor-generator, in which a decrease in driving force and a loss in abrasion are prevented, by reducing an abrasion loss between a commutator and a brush. CONSTITUTION:A commutator 4 is put in a place adjacent to a rotor 2 and fixed to a rotating shaft 1, and a brush 5 is in slide contact with an outer face of the commutator 4. The commutator 4 is made of one ceramic material out of Si3N4, SiC and Al2O3. In addition, the commutator 4 includes a non- conductive member 8 made up of a closely formed ceramic ring part and a plurality of tooth parts 13, and a conductive member 15 made of porous ceramic impregnated with copper alloy between the tooth parts 14. In addition, the rotor 2 and the commutator 4 are electrically connected to each other with wires 6 and 16. The brush is made of mixed powder of graphite, MgP2, and copper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed DC motor / generator in which a sliding contact surface between a commutator and a brush has a low friction.

[0002]

2. Description of the Related Art Conventionally, in a DC motor generator, a coil is arranged in a rotor, and a current is passed through the coil to obtain a driving force by the action of an electromagnet arranged in a stator. In addition, since a generator or an electric motor using a permanent magnet as a rotor has features of high output and simple structure, it has recently been widely used for industrial equipment. However, in order to control the increase in the torque and rotation of the rotor in the generator, it is necessary to change the frequency, voltage and current in the stator coil, and to properly control the rotation and torque thereof, it is necessary to provide an inverter, It has a drawback that the structure becomes very complicated.

Therefore, various methods for converting the magnetic flux density of the permanent magnet incorporated in the generator have been considered.
For example, in a generator, a method is known in which a large gap is formed between a rotor of a permanent magnet and a stator core, a material having a good magnetic force is placed in this gap, and the rotor is pulled out in the axial direction. For example, in the small generator disclosed in Japanese Utility Model Laid-Open No. 2-146975, a main shaft and a rotor are connected via a governor mechanism in which a governor weight is pivotally supported by a pair of links. The weight is separated from the main shaft by a centrifugal force to reduce the angle between the links, and the rotor is moved in the direction of coming out of the stator.

[0004]

However, the induction generator such as the conventional generator has a problem that the control device becomes large and the control becomes complicated. Further, although many DC motor generators have been conventionally developed, there are problems that the friction between the commutator and the brush is large and the wear is large.

In the conventional DC motor generator, as the number of rotations of the rotor increases, the larger the current flowing in the coil of the rotor, the more the electric discharge and the like generated between the commutator and the brush, and the brush portion. The wear of the brush increased, and the durability of the brush became a big problem. In other words, the biggest drawback of the DC motor generator is the occurrence of troubles such as friction between the brush and the commutator and wear of the contact points between the two.

Therefore, an object of the present invention is to configure a sliding contact surface between a commutator and a brush in a DC motor generator to have a low friction coefficient and to prevent the occurrence of air discharge between the brush and the commutator. In order to reduce the friction coefficient of the brush against the commutator, reduce the wear of the brush, and smooth the flow of current between the brush and the commutator. , The material of the brush and the commutator is selected as the optimum material for optimization, and the structure between the commutator and the brush is configured to have low friction, and the material of the brush and the commutator is selected for the optimum combination. Thus, a high-speed DC motor generator having improved wear resistance, corrosion resistance, and durability is provided.

[0007]

In order to achieve the above object, the present invention is constructed as follows. That is, the present invention comprises a rotating shaft rotatably supported by a machine base, a rotor having conductors arranged on the outer periphery attached to the rotating shaft, a stator core and a stator coil arranged on the outer periphery of the rotor. In a high-speed DC motor generator having a stator, a commutator fixed to the rotating shaft adjacent to the rotor, and a brush arranged in sliding contact with an outer peripheral surface of the commutator, the commutator is dense. A non-conductive member composed of a ring portion made of ceramics and a plurality of tooth portions extending outward from the ring portion, and a conductive member obtained by impregnating porous ceramics disposed between the tooth portions with a metal are provided. The dense ceramics and the porous ceramics are alternately laminated and made of the same material, and the conductor wire of the rotor and the conductive member of the commutator are conductors of respective wires and teeth. Member is electrically connected, as energized current flows between a pair of brushes, brushes in contact with the commutator made of metal impregnated on the porous ceramics least reacting graphite and MgP ₂ at high temperatures The present invention relates to a high-speed DC motor / generator, which is composed of powder synthesized by the above method.

In this high-speed DC motor generator,
The dense ceramics and the porous ceramics constituting the commutator are any one of silicon nitride, silicon carbide and alumina, and the metal impregnated in the porous ceramics is an alloy containing copper as a main component, S for alloy
It contains n and Zn. In some cases, the alloy is mixed with graphite or carbon to impregnate the porous ceramics.

Further, in this high-speed DC motor generator,
The brush is kneaded with a mixed powder containing graphite and MgP ₂ and a copper powder, heated, and baked to solidify.

Alternatively, in this high-speed DC motor generator,
There is also a method in which the brush is produced by kneading a mixed powder containing graphite and MgP ₂ and B ₄ C and sintering the mixture under pressure.

In this high speed DC motor generator,
The rotor has conductors arranged outside the laminated silicon steel plates,
The outer circumference of the silicon steel plate is reinforced by a reinforcing cylinder, and the conductive members are respectively arranged in holes formed in the outer circumference of the silicon steel plate so as to be circumferentially spaced.

[0012]

The high speed DC motor generator according to the present invention is constructed as described above and operates as follows. That is, in this high-speed DC motor generator, a commutator is fixed to a rotating shaft adjacent to a rotor, a brush is arranged in sliding contact with the outer peripheral surface of the commutator, and the commutator is made of ceramics of the same material. In addition, the commutator is constructed by disposing a conductive member in which porous ceramics are impregnated with metal between the teeth of a non-conductive member made of dense ceramic, and the brush is made of high temperature at least graphite and MgP _2. Since graphite and MgP ₂ have a function as a conductor and a solid lubricant because they are composed of the powder synthesized by the reaction in step _2, they can perform good lubrication against the high speed rotation of the commutator. That is, the solid lubricant composed of graphite and MgP ₂ has a friction coefficient of 0.08 at room temperature and a small 0.04 at high temperature, and can perform good lubrication at high temperature, that is, high speed rotation, and The friction generated between the brush and the brush can be reduced, the loss of the rotational force of the rotary shaft, that is, the driving force, due to the friction can be reduced, and the wear can be reduced.

In the commutator, the dense ceramic and the porous ceramic are any one of silicon nitride, silicon carbide and alumina, and the metal impregnated in the porous ceramic has copper as a main component. Even if an air discharge is generated between the commutator and the brush, the heat resistance is excellent and the wear resistance and the corrosion resistance can be improved. Also, Cu
Has good conductivity and has a relatively low melting point, so that it is easy to impregnate the pores of the porous ceramics. Furthermore, since the base material forming the commutator is silicon nitride and Cu is impregnated in the porous portion, Cu is partially dropped from the porous portion due to sliding of the commutator with respect to the brush. Also, the graphite forming the brush is embedded therein. Therefore,
The commutator has a very low friction coefficient and a low electric resistance.

[0014]

Embodiments of the high-speed DC motor generator according to the present invention will be described below with reference to the drawings. 1 is a sectional view showing an embodiment of a high-speed DC motor generator according to the present invention, FIG.
1 is a sectional view taken along the line AA of FIG. 1, and FIG. 3 is a sectional view taken along the line BB of FIG.

Although not shown in the drawings, the high-speed DC motor generator has a rotating shaft 1 rotatably supported by a housing through a bearing. For example, a turbocharger,
The present invention can be applied to a rotary electric machine that is incorporated in an energy recovery device, an engine, a cogeneration engine, or the like to convert rotation into electric energy or to apply a rotating force to the rotating shaft 1.

This high-speed DC motor generator is mounted on a rotor (rotor 2) attached to a rotary shaft 1, a machine base (not shown) such as a housing, a base, and a support arranged on the outer periphery of the rotor 2. It has a fixed stator or stator 3, a commutator 4 fixed to the rotary shaft 1 adjacent to the rotor 2, and a brush 5 arranged in sliding contact with the outer peripheral surface of the commutator 4. . The rotor 2 and the commutator 4 are connected by a sleeve 17 made of dense ceramics, which is fixed to the rotating shaft 1, so as to rotate integrally. Also,
A nut 11 is screwed into the rotating shaft 1 on the outer end surfaces of the rotor 2 and the commutator 4, so that the rotor 2 and the commutator 4 do not move relative to each other in the axial direction and disassemble. And the commutator 4 are fixed in the axial direction.

In this high-speed DC motor generator, the stator 3 has a stator core 12 fixed to a machine base (not shown) such as a housing, a base and a support, and the stator core 1.
Stator coil 13 wound around the second field core 20
It consists of and. The rotor 2 has a large number of laminated silicon steel plates 7. These silicon steel plates 7 are fixed by plates 9 and 18 arranged on the silicon steel plates 7 on both sides. On the outer peripheral surface of the laminated silicon steel plates 7, a reinforcing cylindrical body 1 made of a magnetic material such as carbon fiber or high tensile steel
It is reinforced with 9. In addition, a large number of holes are pierced in the outer peripheral portion of the laminated silicon steel plates 7 so as to be spaced apart in the circumferential direction, and the conductor 16 as a conductive member is formed in these holes. Aluminum alloys are poured respectively.

In this high-speed DC motor generator, the commutator 4 has a dividing function composed of the non-conductive member 8 and the conductive member 15, and is formed in a cylindrical body made of ceramics of the same material. . The non-conductive member 8 is composed of a ring portion 21 made of dense ceramic and a tooth portion 14 which is spaced from the ring portion 21 in the circumferential direction and extends outward. Further, the ring portion 21 is configured integrally with the sleeve 17 fixed to the rotating shaft 1. Conductive member 15
Is formed by impregnating the porous ceramics disposed between the teeth 14 with a metal, and has a fan-shaped cross section with a short arc length. In other words, the commutator 4 is formed into a cylindrical molded body by alternately stacking the dense molded body forming the tooth portion 14 and the porous molded body forming the conductive member 15 having a fan-shaped cross section.
The cylindrical compact is fired to produce a cylindrical sintered body, and then a metal is poured into the porous portion of the cylindrical sintered body to produce a cylindrical composite. Then, the outer surface of the cylindrical composite body is ground to adjust the surface roughness, and a cylindrical composite body having a good surface roughness is manufactured.

The dense ceramics and porous ceramics constituting the commutator 4 are any one of silicon nitride Si ₃ N ₄ , silicon carbide SiC and alumina Al ₂ O ₃ .
The metal impregnated in the porous ceramics is an alloy containing copper, Sn, Zn and the like as a main component. Alternatively, with respect to the alloy, since Cu has good compatibility with graphite or carbon, it is possible to mix Cu with graphite or carbon to impregnate the porous ceramics. The porous ceramics forming the conductive member 15 is made into a dense composite material by impregnating the porous portion with an alloy. The conductive wire 16 of the conductive member of the rotor 2 and the conductive wire 6 of the conductive member of the commutator 4 are electrically connected by the conductive member 22.

In this high-speed DC motor generator, the brush 5 is fixed to the end bracket 10 fixed to the machine base. The brush 5 contains graphite and MgP ₂
The powder synthesized by reacting at a high temperature of 00 ° C. to 1000 ° C. is kneaded and reinforced with another material such as copper powder, and baked and solidified. At this time, the brush component is 50 to 60 wt% graphite, 40 to 30 wt% Cu, and Mg.
It is sintered by mixing P ₂ with 10%. Alternatively, the brush 5 can be operated by kneading a mixed powder containing graphite and MgP ₂ and B ₄ C without using the copper powder and sintering the mixture by a pressure sintering method.

The mixed material of graphite and MgP ₂ has a function as a solid lubricant and has a low friction coefficient at a high temperature. Therefore, it is most suitable for a material which rotates at a high speed to raise a temperature. That is, the mixed material of graphite and MgP ₂ is
The friction coefficient is 0.08 at room temperature, but when the temperature rises and becomes high, the friction coefficient decreases to 0.04, which is the same as that of fluid lubrication. Therefore, when a mixed material of graphite and MgP ₂ is applied to the sliding contact surface between the commutator 4 and the brush 5 which rotate relative to each other, the coefficient of friction decreases, and the loss of the driving force of the commutator 4 due to friction can be reduced. And moreover,
Very little wear.

[0022]

The high-speed DC motor generator according to the present invention is
It is configured as described above and has the following effects. That is, this high-speed DC motor generator, as described above,
The commutator ring portion and the tooth portion are made of dense ceramics and the conductive member disposed between the tooth portions is made of porous ceramics impregnated with an alloy containing Cu as a main component, and the brush is made of at least graphite. Since it is composed of a powder obtained by synthesizing MgP ₂ and MgP ₂ , the friction between the brush and the commutator can be reduced, the loss of the driving force of the commutator can be reduced, and the wear can be reduced to improve the durability. be able to.

Therefore, this high-speed DC motor generator is incorporated in a turbocharger, an energy recovery device, an engine, a cogeneration engine or the like to convert the rotation of the rotary shaft into electric energy or to convert the electric energy of the rotary shaft into electric energy. It is extremely preferable as a rotary electric machine that converts into rotation. Moreover, since this high-speed DC motor generator is a DC rotating electric machine, the control device does not have to be upsized as with an AC machine, and it can be easily controlled and the speed can be easily controlled. it can.

In this high speed DC motor generator,
Since the commutator is composed of dense and porous ceramics made of Si ₃ N ₄ , SiC or Al ₂ O ₃ and a copper alloy impregnated in the porous portion, the commutator and the brush No air discharge occurs between and, and wear resistance, corrosion resistance, and durability can be further improved. Furthermore, since the brush is kneaded with a mixed powder containing graphite and MgP ₂ and a copper powder, and heated and baked, the brush is made of a solid lubricant. Even if the child rotates at high speed and becomes high temperature, the friction between the sliding contact between the commutator and the brush does not increase, and the friction coefficient decreases, which is extremely preferable for the high-speed rotating electric machine. Become.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a high-speed DC motor generator according to the present invention.

2 is a cross-sectional view taken along the line AA in FIG.

3 is a cross-sectional view taken along the line BB in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotating shaft 2 rotor 3 stator 4 commutator 5 brush 6,16 conducting wire 7 silicon steel plate 8 non-conductive member 12 stator core 13 stator coil 14 tooth portion 15 conductive member 19 reinforcing cylindrical body 21 ring portion

Claims (6)

[Claims] 1. A rotating shaft rotatably supported by a machine base, a rotor having a conductor attached to the outer periphery of the rotating shaft,
A stator including a stator core and a stator coil arranged on the outer circumference of the rotor, a commutator fixed to the rotary shaft adjacent to the rotor, and a sliding contact with the outer peripheral surface of the commutator. In a high-speed DC motor generator having a brush, the commutator is a non-conductive member composed of a ring portion made of dense ceramics and a plurality of teeth extending outward from the ring portion, and a non-conductive member disposed between the teeth. A conductive member in which a provided porous ceramic is impregnated with a metal, wherein the dense ceramics and the porous ceramics are alternately laminated and are made of the same material; and the conductor wire of the rotor and the commutator. The conductive member is electrically connected to the conductive member of the tooth portion, and the number of brushes contacting the commutator made of the metal impregnated in the porous ceramics is small. Fast DC motor generator, characterized by being composed of Kutomo graphite and MgP ₂ from synthesized powders by reacting at elevated temperature. 2. The dense ceramics and the porous ceramics forming the commutator are any one of silicon nitride, silicon carbide and alumina, and the metal impregnated in the porous ceramics has copper as a main component. The high-speed DC motor generator according to claim 1, which is an alloy containing Sn and Zn. 3. The high-speed DC motor generator according to claim 2, wherein graphite or carbon is mixed with the alloy to impregnate the porous ceramics. 4. The brush comprises graphite and MgP ₂
The high-speed DC motor / generator according to any one of claims 1 to 3, wherein the mixed powder containing and is kneaded, heated and baked. 5. The brush comprises graphite and MgP ₂
Fast DC motor generator according to claim 1, preparative kneading the mixed powder and B ₄ and C containing, characterized in that it is actuated by pressure sintering. 6. The rotor is reinforced by reinforcing cylinders on the outer periphery of laminated silicon steel plates, and the conductive members are respectively arranged in holes formed in the outer peripheral portion of the silicon steel plates in a circumferentially spaced manner. The high-speed DC motor generator according to any one of claims 1 to 5, wherein each of the formed wires is connected to the conductive tooth portion of the commutator.