JPS58148642A - Carbon brush for rotary electric machine - Google Patents

Abstract

PURPOSE:To improve the lubricating performance of a carbon brush particularly at a high temperature with less frictional coefficient and less variation in timing by adding aluminum powder of specific particle diameter to graphite powder of specific ash content, further adding a binder to the mixture, mixing, pressure molding the mixture and then heat treating it at the specific temperature. CONSTITUTION:0.1-2.0wt% of aluminum powder havng particle diameter smaller than 100 mesh is added to graphite powder of main row material which contains at least less than 1.0wt% of ash content. The graphite powder, the aluminum powder and binder such as bisphenol a type epoxy resin or the like are mixed, and the mixture is pressure molded, for example, in the range of 1,000- 2,000kg/cm<2>, and heat treated in the range of 500-650 deg.C in the vicinity of the melting point of the aluminum under the atmosphere shielding oxygen. In this manner, a brush which has excellent lubricating performance even at a high temperature with less frictional coefficient and less variation in timing can be obtained.

Description

[Detailed description of the invention] do.

More specifically, it is used in commutators used in DC motors, DC generators, AC commutator motors, etc., and slip rings used in synchronous motors, synchronous generators, induction motors, etc., and is extremely excellent. The present invention relates to a car sealing brush for rotating electric machines having excellent performance.

Commutator brushes or slip ring brushes (hereinafter often referred to simply as brushes) play the role of flowing current from a stationary part to a rotating part, or from a rotating part to a stationary part of a rotating electric machine such as an electric motor, and are used to control the rotational current. This is extremely important as it affects performance. The brushes used for this purpose are, of course, affected by the structure of the brush holder, the gap between the holder box and the brush, machine vibrations, atmospheric conditions, etc. when in contact with the commutator or slip ring. , is also greatly affected by the brush material. In particular, recent rotating electric machines have become faster and smaller, and load fluctuations have become larger in use. As a result, as the vibration level of the machine increases and the circumferential speed increases, commutation deteriorates and brush wear increases, so there is a demand for a brush material that has as small a coefficient of friction as possible and that exhibits minimal fluctuations in the coefficient of friction.

Furthermore, as the circumferential speed of the rotating electrical machine increases, the contact state of the brush deteriorates, and the contact voltage drop increases. A high contact voltage drop is generally due to the well-known formation of excessive film on the commutator or slip ring, which can lead to unstable sliding contacts. ,
This is undesirable because sparks are likely to occur due to overheating due to the main current flowing under the brush. Various proposals have been made to solve these problems.

For example, a method of impregnating carbon with an oil-based lubricant has been proposed as a method to reduce the friction coefficient of brushes, but in high-speed rotating machines, the temperature of the brush increases and the viscosity of the impregnated lubricant decreases. This is not desirable as it may cause the phenomenon of leakage.

Carbon brushes for electrical machinery, which are generally used as brushes with a low coefficient of friction, use electrolytic graphite as the main raw material and thermosetting resin as the binder, into which metal powder, mainly copper powder, is added. It is made by mixing, molding, pressurizing, and heating and sintering. It is true that brushes made by this method have a lower coefficient of friction than those that do not contain metal powder, but due to the abrasive action of the copper powder, the coefficient of friction and its fluctuations increase when used for a long time. In rotating electric machines with high speeds, the seating of the brush becomes unstable and commutation deteriorates.

Therefore, the brushes suffer from increased wear due to the generation of sparks, resulting in a shortened service life.

In order to improve the above-mentioned drawbacks, for example,
05-5 for graphite powder as shown in 7680
A brush containing heavy weight aluminum powder and heat-treated at a temperature of 350° C. or lower has been proposed. The brush disclosed here has achieved some results in reducing the coefficient of friction, etc., but considering the performance of brushes required today, the degree of reduction in the coefficient of friction and the performance against deterioration due to long-term operation are difficult to determine. It is hard to say that the points are sufficient.

In view of these points, the present inventors have developed an extremely superior coating for rotating electric machines that meets the demands of the times by producing a coating with a small friction coefficient, little variation over time, and a small contact voltage drop, that is, an excessive coating. The present invention was achieved as a result of intensive research to obtain a carden brush.

Therefore, an object of the present invention is to provide an extremely excellent carbon brush for a rotating electrical machine that has a small coefficient of friction, little variation over time, and excellent lubrication performance even at high temperatures.

These and other features, features and benefits will become apparent from the detailed description provided below.

According to one embodiment of the invention, the ash content is at least 1.
In a carbon brush whose main raw material is graphite powder with a weight ratio of 0 or less and a thermosetting resin as a binder, the particle size is as small as 100 mesh with a weight ratio of 0.1 to 2.0 relative to the graphite powder. After adding aluminum powder, mixing the graphite powder, the aluminum powder, and the binder and press-molding,
A cardan brush for a rotating electric machine is provided which is heat-treated at a temperature in the range of 0°C.

Furthermore, according to another aspect of the present invention, in a car brush made of graphite powder having an ash content of at least 1.0% by weight or less as a main raw material and using a thermosetting resin as a binder, Phosphoric acid having a phosphorus content of 0.1 to 3.0% by weight relative to the aluminum powder having a 0.1 to 2.0% by weight ratio;
Adding at least one phosphorus-containing compound selected from metal phosphates, phosphorous acid, metal phosphides, and phosphorus sulfide,
A carbon brush for a rotating electric machine is provided by mixing the graphite powder, the aluminum powder, the phosphorus-containing compound, and the binder, press-molding the mixture, and then heat-treating the mixture at a temperature in the range of 500 to 650°C.

Furthermore, according to one aspect of the present invention, in a carbon brush using graphite powder as a main raw material with an ash content of at least 10% by weight or less and using a thermosetting resin as a binder, a carbon brush with an ash content of at least 10% by weight or less and a thermosetting resin as a binder is provided. ~2.0% by weight of 100 mesh aluminum powder with a small particle size, and 3.5 to 70% by weight of borosilicate (-BO,) to the aluminum powder, monosaccharide. A boric acid ester metal salt containing at least one metal salt selected from the metal group of Group 2 of the Periodic Table of at least one boric acid ester selected from the group consisting of a reduction product and a monosaccharide dimer. , the graphite powder, the aluminum powder, the boric acid ester metal salt, and the binder are mixed, pressure-molded, and then heat-treated at a temperature in the range of 500 to 650°C. is provided.

A brush for a rotating electrical machine according to an embodiment of the present invention uses graphite powder as a main material with an ash content of at least 1.0% by weight or less,
In carbon brushes using thermosetting resin as a binder,
Add 100 meshes of aluminum powder with a particle size as small as 0.1 to 2.0 weight to the graphite powder, mix the graphite powder, the aluminum powder, and the binder and press-mold. This brush is heat-treated at a temperature of 500 to 650°C.

The main raw material of the brush according to the present invention has an ash content of at least 1
．． Graphite powder with a weight factor of 0 or less is used, and the average particle size is usually 5
00 to 800 mesh (Tyler) graphite powder is preferably used. As the graphite, natural graphite, ordinary artificial graphite obtained by subjecting graphitizable carbon such as petroleum coke, coal coke, or pitch coke to heat treatment for graphitization, quiche graphite, or pyrolytic graphite are used. .

Thermosetting resins used as binders in the present invention include bisphenol A epoxy resins, novolac epoxy resins, resol phenolic resins, novolac phenolic resins, alkylphenol resins, alicyclic glycytyl ether resins, and the like. An example of a bisphenol A epoxy resin is EPIKOTE.
) -1004, -1002, -1001, -836,
-834 [Shell Chemical Company (5hell Chemi)
There is a trade name of bisphenol A type epoxy resin manufactured by Cal Corp-+ U-8, A, ). An example of a novola-type epoxy resin is EPIKOTE.
) -154, -153 [Shell Chemical Company (5hel
l Chemical Corp, r U-8,A-
) There is a trade name for the novolac type epoxy resin for the ke. An example of a resol type phenolic resin is VP-13N (trade name of a resol type phenolic resin manufactured by Hitachi Chemical Co., Ltd.), and an example of a novolak type phenolic resin is I (
Examples of alkylphenol resins include P-607N (trade name of novolak phenolic resin manufactured by Hitachi Chemical Co., Ltd.), H-2400 (trade name of alkylphenol resin manufactured by Hitachi Chemical Co., Ltd.), and alicyclic glycidyl ether. Examples of resins include Chissonox (C) II
SSONOX) -206, -221, -289 (trade name of alicyclic glycytyl ether resin manufactured by Chisso Corporation). Mixtures of the above-mentioned resins with urea resins, melamine resins or polyester resins can also be used as binders in the present invention.

The amount of binder added is 2 parts by weight per 100 parts by weight of graphite powder.
It is 5 to 50 parts by weight.

The aluminum powder used in the brush of the present invention is granular,
Any scale-like product may be used, and those with a particle size as small as 100 mesh (Tyler) are used. There is no lower limit to particle size. Table 1 shows the particle size distribution of an example of aluminum powder used in the present invention.

Table 1 The amount of aluminum powder used in the present invention is 0.1 to 20% by weight, preferably 0.15 to 1.0% by weight, based on the graphite powder that is the main raw material.

The present invention Niokel pressure cover 10oO~2oookg/c
rIL2 range.

The heat treatment temperature in the present invention is 500 to 650°C, which is close to the melting point of aluminum, and the heat treatment is performed in an oxygen-blocking atmosphere, that is, in an atmosphere of gas such as hydrogen or nitrogen. Because the aluminum is heat-treated at high temperatures, the shape of the aluminum becomes similar after the heat treatment, whether it is granular or scaly. There is no significant effect on the effect.

A brush is obtained by cutting the molded block obtained in the above manner into a desired shape and desired size.

The present invention will now be described in more detail with reference to FIG. FIG. 1 shows the relationship between the friction coefficient and the contact voltage drop with respect to the amount of aluminum mixed in. In other words, Figure 1 shows graphite powder, which is the main raw material for the brush.

Aluminum powder was added to the graphite powder in several stages in the range of 01 to 5 weight ratio to produce products with different aluminum contents, and a binder was added to each of the powders, mixed, and pressure molded. The friction coefficient value and contact voltage drop value of each brush obtained by heat treatment at a temperature of 500 to 650° C. are shown. To measure the friction coefficient, a simulated commutator (diameter 25 mm) was rotated by a drive motor at 20.00 Orpm, and the simulated commutator was subjected to 50 OF! Brush (6 x 8 x: 25 mm) pressed and brought into contact with -/cm2 pressure
) and a simulated commutator by measuring the frictional force acting between it and a simulated commutator using a strainer. Measuring the contact voltage drop is
With the commutator rotating at 20.00 Orpm,
The contact voltage drop between the brushes and the commutator was measured by passing a current of 4 A between two brushes that were in contact with the commutator with the commutator in between. The solid line in FIG. 1 shows the friction coefficient, and the dotted line shows the contact voltage drop. As is clear from FIG. 1, when the amount of aluminum mixed is between 0.1 and 20% by weight, both the friction coefficient and the contact voltage drop value are extremely low, and a brush with excellent performance is provided. If the amount of aluminum mixed exceeds the range of 0.1 to 2.0% by weight, both the friction coefficient and the contact voltage drop increase to undesirable values, resulting in very poor performance.

A brush for a rotating electrical machine according to another embodiment of the present invention uses graphite powder as a main material with an ash content of at least 10% by weight or less,
In carbon brushes using thermosetting resin as a binder,
Aluminum powder with a small particle size of 100 mm, 0.1 to 20% by weight based on the graphite powder, and phosphoric acid, phosphorus containing 0.1 to 360% by weight based on the aluminum powder, Add at least one phosphorus-containing compound selected from acid metal salts, phosphorous acid, metal phosphides, and phosphorus sulfide, mix the graphite powder, the aluminum powder, the phosphorus-containing compound, and the binder, and process. After pressure molding, 500-650℃
This brush is heat-treated at a temperature in the range of . The structure other than mixing the phosphorus-containing compound is the same as the structure of the first embodiment described above.

The phosphorus-containing compound used in the present invention is at least one phosphorus-containing compound selected from phosphoric acid metal salts, phosphorous acid, metal phosphides, and phosphorus sulfide. Examples of the metal phosphate include barium phosphate, aluminum phosphate, calcium phosphate, and magnesium phosphate, and examples of the metal phosphide include copper phosphide and manganese phosphide. The content of the phosphorus-containing compound used in the present invention is 0.1 to 3% by weight based on the phosphorus content relative to the aluminum powder used.

Next, the present invention will be explained in more detail with reference to FIG. Figure 2 shows brushes with different phosphorus contents.Aluminum phosphate is added to graphite containing aluminum powder in a ratio of 0 to 20 parts by weight (0 to 5 parts by weight in terms of phosphorus content). qb) were added in several stages to make four types with different aluminum phosphate contents, thermosetting resin was added to each, mixed, and after pressure molding, heat treatment at a temperature of 500 to 650°C. The graph shows the change in the coefficient of friction of the brush over time. A in Figure 2
B is a brush containing 0.3% by weight of aluminum powder based on graphite powder, which is the main raw material of the brush, and B is a brush containing 0.3% by weight of aluminum powder based on graphite powder, which is the main raw material of the brush.
A brush containing 1.2% by weight of aluminum phosphate (0.3% by weight in terms of phosphorus content) based on the aluminum powder; A brush containing 0.3% by weight of powder and further containing 6% by weight of aluminum phosphate (phosphorus content: 15% by weight) based on the aluminum powder, D
is a brush containing 0.3% by weight of aluminum powder based on graphite powder, which is the main raw material of the brush, and further containing aluminum phosphate (5% by weight with a 200% phosphorus content) based on the aluminum powder. It can be seen that the friction coefficients of each foot change over time, and the friction coefficients hardly change over time. However, when the phosphorus content exceeds 300% by weight relative to the aluminum powder, the friction coefficient increases over time compared to the one without the addition of phosphorus-containing compounds, and the O11
If the weight percentage is too low, the effect will not be obtained.

Next, Table 2 shows the contact voltage drop values of the brushes after 600 hours of use.

The initial contact voltage drops of the brushes A, B, C, and D in Table 2 are almost the same for all brushes, ranging from 0.7 to 0.9 (V), but 6
After 00 hours, other differences appear as shown in Table 2. If the content of aluminum phosphate in aluminum powder exceeds 3.0% by weight as a phosphorus component, D
as in the case of brushes,
If the phosphorus component is less than 0.1% by weight, the effects of the present invention cannot be obtained. However, similar to the results of the friction coefficient in Figure 2, the non-brushes (B, C) containing phosphorus in the range of 0.1 to 3.0% by weight based on the aluminum powder showed a contact voltage even after 600 hours of use. It can be seen that the drop value is small and no excessive film is formed.

A plastic plate for a rotating electrical machine according to yet another embodiment of the present invention is
The ash content is at least 1. In Carzanplash, which uses graphite powder as the main raw material and a thermosetting resin as a binder, the graphite powder has a weight ratio of 0.1 to 20% by weight.
In addition, aluminum powder with small particle size and boric acid radical (-BOρ amount of 3
．． At least one boron ester selected from the group consisting of monosaccharide reduction products and monosaccharide dimers with a weight ratio of 5 to 70% At least one selected from the group of metals in Group 2 of the Periodic Table Add boric acid ester metal salt containing metal metal salt,
After mixing the graphite powder, the aluminum powder, the boric acid ester metal salt, and the binder and press-molding the mixture,
This brush is heat-treated at a temperature in the range of 0°C. The structure other than mixing the boric acid ester metal salt is the same as the structure of the first embodiment described above.

The boric acid ester metal salt used in the present invention is
-2673, at least one boric acid ester selected from the group consisting of monosaccharide reduction products and monosaccharide dimers; It is a borate ester metal salt containing a metal salt.

As the reduction product of the above-mentioned monosaccharide in the present invention, for example, sorbitol or mannitol, which is a reduction product of glucose or fructose, can be used, and the above-mentioned monosaccharide dimer is generally called a trisaccharide. For example, sucrose, maltose, lactose, etc. are used. As the above-mentioned metal of Group 2 of the periodic table, magnesium, calcium, zinc, barium, etc. can be advantageously used.

Specific examples of the above-mentioned boric acid ester metal salts include boric acid ester magnesium salt obtained by neutralizing boric acid ester produced by reacting sorbitol and boric acid with magnesium oxide, and sucrose boric acid produced from sucrose and boric acid. Boric acid ester magnesium salt obtained by neutralizing acid ester with basic magnesium carbonate, boric acid ester barium salt obtained by neutralizing boric acid ester produced by reacting sorbitol and boric acid with barium hydroxide, sorbitol Examples include boric acid ester calcium salts obtained by neutralizing boric acid esters produced by reacting alcohol and boric acid with hydroxide.

In the brush of the present invention, the content of the boric acid ester metal salt with respect to the aluminum powder is such that the boric acid group (-BO3
) is 35 to 70% by weight.

[Brief explanation of drawings]

FIG. 1 is a graph showing changes in the coefficient of friction when a brush containing aluminum is used for a long time with respect to the amount of aluminum mixed in. Patent Applicant: Toyo Tanso Co., Ltd. Shunsunen Eel Den W (〉) A (Amendment to Procedures for Interfering with Results (Method) % Formula % 1. Indication of the Case 1982 Patent Application No. 028112 26 Name of Invention For rotating electric machines Carden Zorashi 3, Relationship with the case of the person making the amendment Patent applicant address 7-12 Takeshima 5-chome, Nishiyodo-ku, Osaka Name Toyo Tanso Co., Ltd. 4 Agent address 4-3-1 Akasaka, Minato-ku, Tokyo Joint Building Akasaka 312 No. 6, drawing subject to correction

Claims (7)

[Claims] (1) In a carbon brush whose main raw material is graphite powder with an ash content of at least 10% by weight and whose binder is a thermosetting resin, 01 to 20% by weight of 100% by weight based on the graphite powder is used.
Carbon for rotating electric machines made by adding aluminum powder with a smaller particle size than the mesh, mixing the graphite powder, the aluminum powder, and the binder, pressure-molding, and then heat-treating at a temperature in the range of 500 to 650°C. brush. (2) In a carbon brush whose main raw material is graphite powder with an ash content of at least 10% by weight and which uses a thermosetting resin as a binder, the carbon brush contains 0.1 to 20% by weight of 10% by weight based on the graphite powder.
Aluminum powder with a small particle size and a phosphorus content of 01 to 301 to 30 for the aluminum powder
Add at least one phosphorus-containing compound selected from wt% acid, metal phosphate, phosphorous acid, metal phosphide, and phosphorus chloride, and add the graphite powder, the aluminum powder, the phosphorus-containing compound, and the bond. After mixing the agent and press molding, 500 ~
A carbon brush for rotating electric machines that is heat-treated at a temperature in the range of 650℃. (3) The car pump for a rotating electric machine according to claim (2), wherein the metal phosphate is barium phosphate, aluminum phosphate, calcium phosphate, or magnesium phosphate. (4) The carbon brush for a rotating electric machine according to claim (2), wherein the metal phosphide is copper phosphide or manganese phosphide. (5) In a carbon brush whose main raw material is graphite powder with an ash content of at least 10% by weight, and which uses a thermosetting resin as a binder, 10% by weight of O, 1 to 20% by weight based on the graphite powder is used.
From aluminum powder with a small particle size and monosaccharide reduction products and monosaccharide dimers with a boric acid group (-BO3) content of 3.5 to 70% by weight based on the aluminum powder. At least one boric acid ester selected from the group consisting of at least one boric acid ester metal salt of at least one metal selected from the metal group of Group 2 of the periodic table is added, and the graphite powder and the aluminum powder are added. , the boric acid ester metal salt and the binder are mixed and pressure molded, and then 500~
A cargo plastic for rotating electric machines that is heat-treated at a temperature in the range of 650℃. (6) The rotation according to claim (5), wherein the monosaccharide reduction product is sorbitol or mannitol, and the monosaccharide dimer is sucrose, maltose, or lactose. Electric car? Npurashi. (7) The carbon brush for a rotating electric machine according to claim (5), wherein the metal of Group 2 of the periodic table is magnesium, calcium, zinc, or barium.