JPH01298666A - Current collecting device for rotating electrical equipment - Google Patents

Abstract

PURPOSE:To accommodate to a high speed operation and an increase in capacity at low cost by forming the surface by the atomic bonding with dispersion of the coat of an intermetallic compound, and improving the adhesion between the metal base material and the coat. CONSTITUTION:A coat 3c of an intermetallic compound excellent in abrasion resistance and arc resistance is formed on the outer circumferential surface of a ring metal base material 3' forming the body of a collecting ring 3 by atomic bonding with dispersion. The coat 3c is formed by the ion mixing method using titanium nitride as the component, and it contains a solid lubricating material to improve the abrasion resistance to a brush 4. This constitution of the collecting ring 3 improves the adhesion between the coat 3c and the metal base plate 3'. Thus, the abrasion resistance, damage resistance, radiating characteristic, electric characteristic, and mechanical strength of the collecting ring 3 and the brush 4 are improved to enable the accommodation to a large capacity of the rotating electricity. Also, the formation of the coat 3c and the mounting work of lead wires are made easy, resulting in a reduction in cost.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a current collector for a rotating electric machine, and more specifically,
It relates to a current collector ring (slip ring or commutator) that makes sliding contact with a flange to exchange current.

[Conventional technology]

Current collectors for rotating electric machines are used to generate rotating or linear motion from a stationary body, such as supplying field current for a rotating field type alternating current generator, supplying armature current for a rotating armature type DC motor, and supplying driving power for a train. It is well known that current and power are supplied inside the body. In this type of current collector, a brush of a stationary body and a current collector ring (slip ring or rectifier 7-) of a rotating body are in mechanical contact to exchange current.

The structure itself is simple.

Incidentally, in recent years, the capacity of rotating electric machines has increased, their circumferential speeds have increased, their size and weight have been reduced, and there has been a tendency for brush loading to become denser and brush current density to increase. For this reason, the number of operating problems of the rotary FFI machine, such as increased brush wear and rough damage to the current collection ring, has increased, and the number of maintenance and inspections has become more frequent.

As a countermeasure to this problem, a current collection ring using conductive ceramics, as disclosed in Japanese Patent Application Laid-Open No. 61-4178, etc.
and brushes are attracting attention. Conventional examples using conductive ceramics will be explained with reference to FIGS. 6 to 9.

Figure 6 is a schematic diagram showing a conventional example of a current collector for a single-rotation machine;
FIG. 7 shows a cross section taken along line A-A' in FIG. 6 in the force direction. As shown in these figures, there is a slip ring 3 disposed on a rotor shaft 1 of a single-rotation machine with an insulator 2 in between, and a brush 4 is in slidable contact with the outer periphery of the slip ring 3.

The slip ring 3 includes an annular metal base material 3b made of copper, steel, iron, etc., which is fixedly arranged on the axis center side of the rotating shaft 1, and a metal base material 3b.
A cylindrical body 3a made of conductive ceramic is fitted and fixed to the outer periphery of the brush 4, and the surface of the ceramic cylindrical body 3a slides on the brush 4.

Electrically, the brush 4 makes sliding contact on the surface of the cylindrical body 3a, and sends and receives current to and from the windings of a rotating electric machine (not shown) via the lead wire 6. Lead wire 6 is.

The ring 5 presses against the side surface of the slip ring 3. Typical conductive ceramics constituting the cylindrical body 3a include, for example, SiC (silicon carbide),
Zr on a 5iaN4 (silicon nitride) ceramic substrate
A conductive additive such as Bz (siliconium poride) is blended, and the blending ratio is changed to perform high-temperature sintering. SiC and 5
i3Ni is sintered at high temperature as a fine-grained polycrystalline body,
It becomes a solid object. In this case, the shape of the ceramic particles is not necessarily spherical, but may also be sharp.

The use of ceramic for the outer circumferential surface of the current collection ring, which makes sliding contact with the brushes, is effective against a wide variety of factors that can cause damage to the current collection ring, such as corrosive gas, oil, dust, or extremely low or high humidity environments. It becomes almost unaffected by it. In particular, since the sintering temperature of ceramics is higher than that of iron or copper-based metals, they have extremely high resistance to rough damage caused by brush sparks.

[Problem to be solved by the invention]

However, on the other hand, there were various points that should be improved as listed below. Brittle materials such as ceramics have significantly lower fracture toughness than metal materials.1For example, brittle materials such as ceramics have a circumferential speed of 70 to 80 m/s, such as slip rings in turbine generators.
Applications to high-speed rotating bodies include destruction of slip rings,
There is a risk of splashing. In addition, in the conventional structure in which the ceramic cylindrical body 3a is fitted to the metal base material, the adhesion (wetting) between the ceramic and the metal material is poor, and therefore, the sixth
As shown in the figure, the lead wires 6 were connected by pressure contact with the ring 5, or by connecting through the welding irradiated surface of the metal material, which increased the number of man-hours per component and required work effort.

In addition, looking at the electrical characteristics of conventional ceramic current collectors, as mentioned above, the adhesion (wetting) between the metal base material and the cylindrical ceramic is poor, so the contact resistance at the contact boundary tends to increase. was there. This increase in contact resistance is not so much of a problem in relatively small-capacity rotating electric machines with a small number of installed brushes, but in large-capacity rotating electric machines (for example, 600 MW class turbine generators), the following problem occurs. A problem arises. That is, in a large-capacity rotating electric machine, the number of brushes attached to each positive and negative slip ring is as large as 60 to 80. For this reason, there are 8 to 10 rows of brushes in the axial direction of the slip ring.
The structure also has an extremely long axis. Therefore, the cylindrical body 3a
If the adhesion between the metal base material 3b and the metal base material 3b is not sufficient, a phenomenon occurs in which the temperature rise due to the contact resistance at the contact boundary portion increases when a large current is applied. In particular, in the case of ceramics, even though they are electrically conductive, their thermal conductivity is poorer than that of general-purpose steel materials, and heat transfer toward the center of the rotating shaft is poor.
Heat generation due to friction loss and electrical loss in the brushes combine to cause a significant temperature rise in the slip ring cylindrical body +1. As a result, new interlayers such as excessive brush wear and chattering due to frictional contact between the shafts of the brushes are occurring.

Furthermore, looking at the sliding situation between the conductive ceramic cylinder 3a and the brush 4, as shown in FIG.
There may be large fluctuations in the If we look microscopically at the contact boundary between the brush 4 and the cylindrical body 3a of the slip ring 3, as explained in FIG. (2) SiC and 5isN+, which are the base materials of the ceramic cylinder 3a, are extremely hard and have poor lubricity. On the other hand, on the surface of the brush 4, a small amount of hard material 4b contained in graphite 4a is exposed, and these hard materials come into contact with each other like protrusions, so (1) and (2) are satisfied. This is because frictional fluctuations between the slip ring and the brush are large, resulting in unstable contact.

The present invention has been made in view of the above points, and its purpose is to improve the wear resistance of a current collector.

In addition to improving roughness resistance, heat dissipation characteristics, if! It is an object of the present invention to provide a current collector for a rotating electric machine that has improved mechanical properties and mechanical strength, can sufficiently cope with high-speed operation and large-capacity rotating electric machines, and is advantageous in terms of cost.

[Means to solve the problem]

The above object is to provide a current collector having a current collecting ring made of a slip ring or a commutator that makes sliding contact with the brushes of a rotating electrical machine to transfer current, and to provide a current collector with a ring-shaped metal base material that is the main body of the current collecting ring. on the outer surface.

This is achieved by forming a film of a conductive intermetallic compound with excellent wear resistance and arc resistance through atomic bonding accompanied by diffusion.

Here, the material for the base material of the current collection ring should be selected from materials that satisfy these requirements, such as copper +
It iron or the like is used.

In addition, examples of intermetallic compound coatings formed on the surface of metal substrates include conductive nitrides, carbides, borides, etc., and N1AQ alloy coatings; is formed using a method such as a physical vapor vapor method, a chemical vapor vapor method, or a thermal spray method.

[Effect]

By forming a film of intermetallic compound on the outer peripheral surface of the metal base material (collector ring main body) through atomic bonding accompanied by diffusion,
The bond (adhesion) between the metal base material and the coating becomes extremely good. Specifically, the boundary between the metal base material and the coating is bonded to such an extent that it is difficult to clearly distinguish it due to the concentration gradient caused by diffusion, and a surface layer with extremely excellent adhesion is formed on the surface of the metal base material.

In addition, the coating formed on the surface of the current collecting ring is a thin film, and most of the current collecting ring is made of a metal base material. The fracture toughness of the current collecting ring is not significantly impaired by the presence of the coating, and the coating itself is highly closely bonded to the metal base material, resulting in a structure that can withstand application to high peripheral speed rotating body models.

Furthermore, since the current collecting ring is mostly made of a metal base material, the current lead wire of the rotating electric machine winding and the sliding ring can be connected directly to the side surface of the metal base material. Reduction in parts man-hours9 Workability can be improved.

Furthermore, the coating formed on the outer peripheral surface of the sliding ring body.

Since it slides with the brush, it is formed of an intermetallic compound that has excellent wear resistance and resistance to brush sparks, etc., but the coating is formed using a physical vapor phase method, a chemical vapor phase method, etc., for example. Using surface treatment technology, it is possible to create a coating with a very dense crystal structure, so there are no irregularly shaped protrusions like in conventional ceramic cylinders, and the coating surface is smooth. , the coefficient of friction on its surface can be lowered.

As a result, stable dynamic characteristics with small frictional fluctuations are obtained during sliding contact with the brush, and since this current collecting ring coating does not impede the sliding movement of the brush, the contact voltage drop between the current collecting ring and the brush can be suppressed.

Furthermore, according to the present invention, as described above, the coating is highly closely bonded to the metal base material serving as the main body of the current collector ring with diffusion, so that the bonding state is such that the boundary between the metal base material and the coating is difficult to distinguish.
As a result, it is possible to reduce the contact resistance between the metal base material and the coating, thereby increasing the electrical conductivity, and also to suppress the temperature rise due to the contact resistance at the contact boundary portion when a large current is applied. In addition, the frictional heat generated by the sliding contact between the current collection ring and the brushes and the heat generated by electrical loss are quickly transferred from the metal base material to the rotor shaft side, and heat diffusion reduces the temperature rise of the brushes and slip ring. It can be lowered. Therefore, the electrical characteristics of the current collection ring and brush can be improved.

〔Example〕

The above five embodiments of the present invention will be described based on FIGS. 1 to 5.

Fig. 1 is a partial cross-sectional view showing only one side of the current collector of this embodiment, and its function is the same as that of the conventional example, and the same reference numerals as those of the conventional example of Fig. 6 described above are the same or common. Indicates an element. The slip ring 3 has its main body 3' made of copper, steel,
Brush 4 is made of iron, etc., and its external shape remains the same.
An intermetallic compound coating 3c, which is the gist of the present invention, is formed on the outer surface of the slip ring in sliding contact with the slip ring by atomic bonding accompanied by diffusion.

The coating 3c is wear resistant against sliding with the brush.

Has electric arc resistance and is resistant to oil, ducts, and corrosive gases.

It must have roughness resistance that can withstand humidity, and must also be a good electrical conductor.

In order to meet such demands, a highly hard intermetallic compound is used as the coating 3c, and preferable examples of the intermetallic compound include various nitrides, carbides, and borides.

Examples of nitrides include titanium nitride (TiN), zirconium nitride (ZrN), and hafnium nitride (ofN).

Vanadium nitride (VN), tantalum nitride (TaN).

Niobium nitride (NbN), chromium nitride (Cr
N, CrzN), etc. Examples of carbides include titanium carbide (TiC) and zirconium carbide (ZrC).

Hafnium carbide (HfN), vanadium carbide (VC),
Tantalum carbide (TaC), niobium carbide (NbC)
, tungsten carbide (WC).

Boron carbide (84G), chromium carbide (CraCz.

Cr7cs, Crzscs), etc. In addition, as a boride, titanium boride (TzBz) * zirconium boride (
ZrBz) to hafnium boride (HfBz), vanadium boride (VB2), tantalum boride (T a B 2) 1
Niobium boride (NbBz), tungsten boride (W
2Bs) p chromium boride (Cr B 2) T iron boride (FeB, FezB), etc. These nitrides,
The hardness of carbide and boride is about Hv1500 to Hv4
The value is within the range of about 000, which is higher than that of metal materials such as copper, steel, and iron for the base material. Therefore, wear resistance can be improved compared to when only metal materials are used, and the specific resistance of nitrides, carbides, and borides is approximately 6 μΩ・
It shows a value within the range of 1 to 800 μΩ·■, which is equivalent to or slightly higher than the metal material such as copper, steel, or iron, which is the material of the base material 3', and is a good conductor. therefore,
Even if a film of nitride, carbide, or boride, which exhibits the aforementioned low resistivity, is formed on the surface of a base material such as copper + fll-iron, it will not affect the power supply and will maintain its properties as a slip ring. can be secured.

Note that the coating 3c is not limited to the above-mentioned coating, and other coatings such as AQNi coating may also meet the requirements.

In addition, although most silicides generally have insulating properties, they can also be used if they have electrical conductivity.

Therefore, it is important that the coating 3c is formed by atomic bonding accompanied by diffusion, particularly on the slip ring surface.

There are various surface treatment methods for film formation, but in this example, since the material of the film to be formed is an intermetallic compound such as nitride, carbide, or boride, a chemical vapor deposition method was used. VaporDepositphone
, hereinafter referred to as CVD method), physical vapor deposition method (Phys
ical vapor deposition (hereinafter referred to as PVD method), thermal spraying method, and the like.

In the CVD method, a raw material to become an intermetallic compound is supplied in gaseous form, and a film of the intermetallic compound is formed by a chemical reaction on the heated surface of the base material. For example, in the formation of a titanium nitride film, T
By supplying i CQ < saturated with a carrier gas of hydrogen gas and using ammonia gas (NIIa) or nitrogen (N2) as a nitrogen source, TiCl2++1/2N2+211z→TiN+4II
CQ...(1) Or TiCff++NIIa+1/2IIz→T i N
+ 4 II CQ (2) A TiN film is formed according to a reaction formula such as (2). The reaction temperature at this time is determined by the free energy of nitride formation (ΔG). In the case of titanium nitride, in the reaction of equation (1),
Normally, a reaction temperature of 620°C or higher is required, but according to the recently developed plasma CVD method using DC glow discharge or high-frequency discharge of 13.56 MIIz, a reaction temperature of 500°C or higher is required.
A titanium nitride film can be formed even at moderately low temperatures. Similarly, a film can be formed on the surface of the substrate using other nitrides, carbides, and borides using the CVD method.

In the PVD method, copper, 11. From the viewpoint of adhesion of the film to the metal base material such as iron, the ion mixing method, ion blating method, sputtering method, ion implantation method, etc. are used. For example, in the ion mixing method, while forming a film of a metal of group 4a, 5a, or 6a' on the surface of a metal base material (sliding ring body) by vapor deposition or sputtering, for example, nitriding is performed. When forming a substance, nitrogen ions can be implanted, and when forming a carbide, carbon ions can be implanted. When implanting nitrogen ions, use a nitrogen-containing gas such as nitrogen gas or ammonia gas, and when implanting carbon ions, use acetylene (Cz
Hz) pmethane (CH4) gas or the like may be used.

The present invention is not limited to these gases, but any gas may be used as long as it can form nitrides and carbides.

For example, when forming TiN (titanium nitride) on the surface layer of a slip ring metal base material, nitrogen ions are acceleratedly implanted into the surface layer, and at the same time, a Ti vapor deposition film is generated on the base material surface and is implanted into the atoms constituting the base material. A mixture layer of nitrogen ions and Ti atoms is formed.

Since this mixture layer has no boundary between the layers and the metal base material, a surface layer with extremely excellent adhesion is formed.

In addition, in the ion blating method, metal titanium, which is a titanium source, is irradiated with an electron beam under reduced pressure to heat it to a high temperature and evaporate it. At the same time, ammonia gas or nitrogen gas is introduced as a nitrogen source, and a gap between the evaporation source and the substrate is A plasma is generated to activate the titanium and nitrogen sources and cause them to react. In this way, titanium nitride is formed, and the coating is performed by accelerating the titanium nitride onto the substrate using a bias potential. Other nitrides can be similarly formed by evaporating the metal source and adding a nitrogen source gas. In the case of carbides, the carbon source may be, for example, hydrocarbon gas, CI
I+ etc. may be used. In the case of boride, it can be formed by simultaneously vaporizing a metal source and a boron source and activating it with plasma.

In addition, in the sputtering method, nitrides and carbides.

A boride target can be used to form a coating on a substrate by a sputtering action. In the case of nitride, it can be made into an intermetallic compound by reactive sputtering, that is, by sputtering a metal source with a nitrogen source gas. In addition, nitrogen ions are added to the surface of the metal base material using ion implantation methods.

A film of nitride, carbide, etc. based on this base material may be formed on the surface of the metal base material itself by implanting carbon ions or the like.

In the thermal spraying method, coating is performed by spraying the raw material for the coating onto the surface of the substrate at high temperature and high speed. For example, in the plasma spraying method, a thermal plasma is generated between an anode and a cathode while flowing a large amount of base gas such as Ar, Nz, IIe, etc. to generate a high-temperature, high-speed plasma flame, and inside this plasma flame By supplying raw material powders such as nitrides, carbides, and borides, these powders are heated to high temperatures and accelerated at high speeds, reaching the surface of the base material,
A film is formed. In the case of plasma spraying, by controlling the gas composition, a desired coating can be formed at a higher speed than with CVD and PVD methods. However, since the surface roughness of the formed film is rougher than that of the CVD method and the PVD method, depending on the purpose, it is preferable in terms of friction properties to perform surface finishing.

The thickness of the intermetallic compound (for example, nitride, carbide, boride) film formed by the above method is preferably thicker in consideration of wear, as long as it does not peel off. Generally, the film thickness formed by CVD method and PVD method is 100
It is about μm or less.

On the other hand, in thermal spraying, the thickness is about 1 mm or less. It should be noted that improvements can be made by combining multiple layers of intermetallic compounds of different materials in order to thicken the coating, and it is desirable to form the coating depending on the purpose.

Here, a specific example of the formation of the coating 3c will be described in Example I below.
, n.

(Example I) In this example, the intermetallic compound (coating) 3c is titanium nitride (T i N), and the slip ring base material is iron,
A steel base material is used, and a TiN film is formed on the surface of this base material by an ion mixing method. Specifically, nitrogen ions are implanted while depositing Ti on the surface of the substrate at a pressure of 10-4 to 6 Torr in a vacuum chamber, and a nitride compound (
T i N) is formed. The ion implantation conditions were: Ti evaporation rate: 3 persons/see, acceleration voltage: 20 KV, and nitrogen ion implantation amount: 2 x 1018 ions/d.Normally, this current collector is used as a current collector and a wear-resistant material as a sliding material. , in order to form the nitride layer 3c with a low coefficient of friction, the amount of nitrogen ions implanted is 1×
It is desirable that the amount is 1018 ions/d or more; if the amount is less than this, a large amount of vapor-deposited metal remains, and the desired characteristics cannot be obtained.

The thickness of this nitride layer 3c is about several μm, and most of the slip rings are made of metal base material, so the connection of the lead wire 6 that transfers current to and from the windings in the rotating electric machine is as shown in FIG. As shown, it is possible to attach the slip ring 3 to the base material 3' using bolts 8, which is usually done, or to process the slip ring 3 by soldering, and the workability of this part is improved.

FIGS. 2 to 4 show examples of experimental results comparing this embodiment with a conventional current collector.

FIG. 2 shows the change over time in the contact voltage drop Vb with the brush using the slip ring of this example. The friction fluctuation is lower than the results shown in FIG. 8 mentioned above.

It can be seen that the brush sliding characteristics are very stable. This is because the nitride layer on the slip ring surface is densely formed like a mirror, and its hardness is about Hv250o, and the coefficient of friction is low. This is because even if the hard material particles are exposed, the nitride layer slides against the hard material, resulting in a low coefficient of friction, and the factors that inhibit brush sliding are eliminated.

As mentioned above, when the brush friction variation is low, other characteristics associated with brush current collection are also significantly improved, and the overall effect is large.

For example, looking at the amount of brush wear, Figure 3 shows the brush wear curve at brush current density δ and brush wear amount W per 1000 hours.
As shown by the curve, it has been halved to about 50%.

In addition, in the tests for each brush current density, there was almost no change in the "roughness" of the slip ring surface before and after operation.

Furthermore, similarly, as shown in FIG. 4, the brush temperature curve is P in the prior art, but the brush temperature curve becomes Q according to the present invention, making it possible to reduce the temperature by 20 to 30%.

This is not due to a reduction in brush friction fluctuations, but because the boundary between the nitride layer that makes up the slip ring and the ring base material becomes unclear due to atomic bonding accompanied by diffusion, resulting in better thermal and electrical conductivity. , friction loss due to brush sliding contact,
This is because heat generated due to electrical loss quickly moves from the slip ring base material to the rotor shaft side, resulting in a large heat dissipation effect. Therefore, temperature increases in both the brush and the slip ring can be suppressed, and the electrical characteristics of the current collector as a whole can be significantly improved.

Further, in this embodiment, the surface coating itself is a ceramic layer, which has the same resistance to brush sparks, rough damage, etc., and its function is equivalent to that of the conventional ceramic cylindrical type. Therefore, in the case of a difficult-to-rectify model with large brush sparks, the roughness resistance can be improved by controlling the thickness of the surface layer forming film.

This can be avoided by taking similar measures for models that operate in an atmosphere containing corrosive gas.

Furthermore, the adhesion of the coating to the metal base material (slip ring main body) is high, and the fracture toughness of the slip ring is also comparable to that of the base material, and it can withstand application to high peripheral speed rotating body models.

(Example ■) In this example, formation of the coating 3c by the CVD method will be described.

In this embodiment as well, an example in which titanium nitride (TiN) is used as the intermetallic compound (coating) 3c and iron material is used as the slip ring base material will be described. In CVD processing, a slip ring for the material to be treated is placed inside the reactor of a reduced pressure vessel, and the inside of the reactor is
After reducing the pressure to below 0-'' Torr, the reactor is heated to 1020°C using an external resistance heating electric furnace while introducing hydrogen gas and maintaining the temperature at 80 Torr.In this state, the metal halide, which is a titanium source, is titanium tetrachloride (T
iC14) and nitrogen gas as a nitrogen source were supplied, and treatment was performed for 8 hours. Through this treatment, the TiN film becomes 10 μm thick.
Been formed.

As mentioned above, when the metal base material is iron, it is possible to apply a coating using the low pressure CVD method.
Some VD methods require high processing temperatures.

In this case, by connecting the product to be treated to the cathode using DC glow discharge and performing the same CVD treatment as described above, it is possible to
A 10 μm TiN film can be formed in 3 hours.

Therefore, this embodiment can also produce the same effects as the embodiment (2).

In each of the above embodiments, nitride TiN was applied to the slip ring as a coating (intermetallic compound) 3c by PVD or CVD.
Although an example formed by method D has been described, similar effects can be obtained with coating materials other than TiN (for example, various intermetallic compounds listed at the beginning of the examples).

It is also possible to form a composite film of intermetallic compounds on the surface of the base material. In particular, in the thermal spraying method, nitride, carbide, and boride powders, which are the raw materials for the coating, are mixed with substances that have so-called solid lubricating properties (e.g., Mo5s, Mn5z, h-BN+
Graphite, etc.), it is possible to obtain a structure in which these solid lubricating elements are dispersed in the film.

Furthermore, even in the case of thermal spray coating alone, for example, by controlling the coating conditions as shown in FIG.

The pores 31 between the target thermal spray particles 30 are dispersed.

A composite structure can also be formed by impregnating the pores 31 with a solid lubricating element (such as lead).

The composite structure as described above makes it possible to improve the sliding properties while maintaining good electrical properties.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to improve the abrasion resistance and roughness resistance of the current collector ring and brushes, as well as improve the heat dissipation characteristics, electrical characteristics, and mechanical strength, and to achieve high-speed rotation and large capacity. It is possible to provide a current collector that is fully compatible with rotating electric machines, and also allows for easy coating formation, as well as easy electrical connection work between lead wires and sliding rings, reducing the cost of one work. This can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a partial vertical sectional view of a current collector showing an embodiment of the present invention, FIG. 2 is a characteristic diagram of brush contact voltage drop of the above embodiment, and FIG. 3 is a current collector of the above embodiment and a conventional current collector. FIG. 4 is an explanatory diagram showing a comparison of brush wear conditions of the above embodiment and the conventional current collector;
FIG. 5 is a partial enlarged sectional view showing another embodiment of the present invention, FIG. 6 is a partial sectional view showing a conventional example of a ceramic type current collector, and FIG. 7 is a sectional view taken along line AA' in FIG. 6. 8 is a characteristic diagram of brush contact voltage drop in the conventional example, and FIG. 9 is an explanatory diagram showing the state of contact between the brush and the surface of the current collecting ring in the conventional example. 1... Rotor shaft, 2... Insulator, 3... Current collector ring,
3'... Current collector ring main body (metal base material), 3c... Intermetallic compound coating, 4... Brush. 1st prisoner 2nd θ↑f's". 63'('/exsu 40th J (A/cat') $5 (2) Me60 1□ Hajime 8th ward square Pl+'1

Claims (1)

[Scope of Claims] 1. In a current collector having a current collecting ring consisting of a slip ring or a commutator that makes sliding contact with the brushes of a rotating electrical machine to transfer current, an annular body serving as the main body of the current collecting ring A current collector for a rotating electric machine, characterized in that a film of a conductive intermetallic compound with excellent wear resistance and arc resistance is formed on the outer peripheral surface of a metal base material through atomic bonding accompanied by diffusion. . 2. In the first claim, the intermetallic compound coating comprises:
A current collector for a rotating electrical machine made of one of nitride, carbide, and boride. 3. In the first claim, the intermetallic compound coating comprises:
A current collector for a rotating electrical machine made of a NiAl film. 4. In any one of claims 1 to 3, the intermetallic compound coating is formed using any one of a physical vapor vapor method, a chemical vapor vapor method, and a thermal spray method. A current collector for rotating electric machines. 5. The current collector for a rotating electric machine according to any one of claims 1 to 4, wherein the intermetallic compound coating contains a solid lubricant for improving frictional characteristics against the brush. 6. The current collector for a rotating electric machine according to any one of claims 1 to 5, wherein the intermetallic compound coating is formed by laminating at least two layers of intermetallic compounds of different materials.