JPH06189505A - Manufacture of brush for rotating electric machine - Google Patents

Abstract

PURPOSE:To provide the manufacture of a brush for a rotating electric machine, which can maintain stable sliding condition even at high speed rotation and besides the life of which is long. CONSTITUTION:This is the manufacture of a bush for a rotating electric machine, which adds 0.2-2wt.% aluminum powder and 1-10wt.% tungsten disulfide powder to graphite powder and thermosetting resin being principal materials, proportioning the quantity of aluminum powder and the quantity of molybdenum disulfide powder or tungsten disulfide powder to each other, and mixes, molds, and heat-treats them.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a rotating electric machine, and more particularly to a brush for a rotating electric machine used in a small rotating electric machine.

[0002]

2. Description of the Related Art As a method of removing an excessive film formed on a commutator surface in order to maintain a stable sliding state, Japanese Patent Publication No. 39163/39 discloses that amorphous silica and an alkali metal or an alkaline earth metal are used. , A metal having a crystallization promoting action on silica such as manganese, aluminum, bismuth, and nickel, and heat-treated at a temperature of 700 to 1000 ° C. are used. In addition, JP-B-58-58787 discloses that harmful commutator skin layer is prevented from being produced, and a proper film adjusting action is given to maintain a stable sliding state even at high speed rotation. 0.5
~ 5 wt% aluminum (Al) powder, 350
There is a method in which a brush heat-treated at a temperature of ℃ or less suppresses the film on the commutator surface from becoming excessive by the film adjusting action of the Al powder, and improves the sitting property of the brush. Further, as shown in Japanese Examined Patent Publication No. 60-13382, 0.5 to 5% by weight of Al powder and 0.05 to 0.5% by weight of SiC powder are simultaneously mixed, and at a temperature of 150 to 350 ° C. With a heat-treated brush, increase the friction coefficient due to the polishing action of SiC powder
There is a method of keeping the sliding state of the brush stable by reducing the friction coefficient and the contact voltage drop by the action of the powder film formation.

[0003]

The method disclosed in JP-B-39-16363 has the effect of removing the film on the commutator surface, but it strengthens the polishing action, and the friction coefficient and its fluctuation are large. Therefore, there is a problem that the efficiency of the rotating electric machine is reduced. Further, although the methods disclosed in Japanese Patent Publication No. 58-58787 and Japanese Patent Publication No. 60-13382 are effective in reducing the friction coefficient, in today's rotary electric machines that are designed to be smaller and lighter in weight and have higher speed, There are problems of low motor efficiency, increased brush wear, and short life. INDUSTRIAL APPLICABILITY The present invention provides a brush for a rotating electric machine, which has a small friction coefficient and little fluctuation, that is, suppresses the formation of an excessive film on the commutator surface, maintains a stable sliding state even at high speed rotation, and has a long life. It provides the law.

[0004]

According to the present invention, 0.2 to 2% by weight of Al powder and molybdenum disulfide (MoS ₂ ) powder or tungsten disulfide (graphite powder and thermosetting resin as main raw materials) are used. The present invention relates to a brush for a rotating electric machine in which 1 to 10% by weight of WS ₂ ) powder is added in proportion to the amount of aluminum powder and the amount of molybdenum disulfide powder or tungsten disulfide powder, and mixing, molding and heat treatment are performed.

In the present invention, the main raw material graphite powder is artificial graphite obtained by graphitizing purified natural graphite, petroleum-based coke, coal-based coke, etc., pyrolytic graphite,
It is a powder such as quiche graphite, and the particle size is not particularly limited.
The ash content is preferably 0.3% by weight or less because if the amount of ash is large, the rubbing characteristics become unstable when a brush is used and scratches are generated on the commutator. The thermosetting resin used as the binder is not particularly limited, but a phenol resin or an epoxy resin is preferable.

Although there are granular and scaly Al powders, usually, Al powders that are easy to mix with the main raw material and have good compatibility with the resin are used. The particle size is preferably 74 μm or less, and particularly preferably 30 to 70 μm. If the particle size is large, it tends to be unevenly distributed in the brush, and if it is too small, the degree of contact failure tends to increase. Further, the MoS ₂ powder or the WS ₂ powder is added as a lubricant, and the particle size thereof is not particularly limited, but usually 1 to 30 μm is used.

The amounts of the Al powder and the MoS ₂ powder or the WS ₂ powder added are 0.2 to 2% by weight and 1 to 10% by weight, respectively, with respect to the main raw material graphite powder and the thermosetting resin. Al
If the amount of powder added exceeds this upper limit, the abrasiveness will increase,
The sliding state becomes unstable. If the added amount of Al powder is less than the lower limit value, the film adjusting action becomes insufficient and an excessive film is formed, so that the sliding state also becomes unstable. Also, M
o If the addition amount of S ₂ powder or WS ₂ powder exceeds 10% by weight,
Not only is it uneconomical because the effect of reducing the friction coefficient has reached a saturated state, it may cause streaks on the commutator surface. On the contrary, if the addition amount is less than 1% by weight, the effect of lubrication does not appear. On the other hand, if either the Al powder and the MoS ₂ powder or the WS ₂ powder are mixed in a large amount or in a small amount, the respective characteristics are emphasized and the above-mentioned problems are likely to occur. Therefore, in the present invention, the Al powder and the MoS ₂ powder or the WS ₂ powder are mixed. Is added proportionally. That is, when the amount of Al powder is small, the amount of MoS ₂ powder or WS ₂ powder is also decreased and the powder is added in a well-balanced manner.

Graphite powder, Al powder in the above amount, MoS ₂ powder or W
The S ₂ powder and the thermosetting resin are mixed to form a molding powder. When the resin is solid, it is appropriately pulverized and mixed by a usual powder mixer, and when the resin is liquid, an appropriate solvent is added, and the mixture is kneaded with a known kneader or the like to remove the solvent and then pulverized to obtain a molding powder. To be done. The molding powder is molded by a known method and heat-treated to be a brush material, which is processed and assembled to a predetermined specification to be a brush.

[0009]

EXAMPLES Examples of the present invention will be described below. Example 1 A novolak type phenol resin (manufactured by Hitachi Chemical Co., Ltd., HP-2) as a binder was added to 70 parts by weight of a main raw material of pitch coke artificial graphite powder having an ash content of 0.1% by weight pulverized to 74 μm or less.
08 NK) powder in an amount of 30 parts by weight,
Granular Al powder of less than μm and Mo with particle size distribution of 1 to 30 μm
S ₂ powder was added in the combination shown in Table 1, put in a Warner type kneader and mixed, and then molded at a pressure of 1.2 t / cm ² .
Then, heat treatment was performed at a temperature of 700 ° C. to obtain eight kinds of brush materials, and the brush materials were processed and assembled to obtain brushes.

[0010]

[Table 1]

Example 2 Eight kinds of brushes were obtained in exactly the same manner as in Example 1 except that the MoS ₂ powder in Example 1 was changed to WS ₂ powder. Comparative Example 1 To 100 parts by weight of the same artificial graphite powder as in Example 1, only the amount of Al powder shown in Table 1 was added, and the same binder as in Example 1 was added in the same amount as in Example 1. Eight kinds of brushes were obtained in exactly the same manner as in 1. Comparative Example 2 The amount of MoS ₂ shown in Table 1 was used in place of the Al powder in Comparative Example 1.
Eight types of brushes were obtained in exactly the same manner as in Comparative Example 1 except that powder was used. Comparative Example 3 Eight kinds of brushes were obtained in exactly the same manner as Comparative Example 2 except that the same amount of WS ₂ powder was used instead of the MoS ₂ powder in Comparative Example 2.

The friction coefficient of each of the eight brushes obtained in Examples 1 and 2 and Comparative Examples 1, 2 and 3 was measured. Next, each brush is attached to an AC 100V, 1 kW AC commutator motor (rotational speed rating 30000 rpm), operated, and
Brush wear per hour was measured. These results are shown collectively in FIGS.

From FIG. 1, the friction coefficient is almost 0.17 or more in the brushes obtained by adding Al powder, MoS ₂ powder or WS ₂ powder alone to the main raw material of the comparative example. In contrast,
0.2 to 2% by weight of Al powder within the scope of the present invention, MoS
The brushes of the examples with ₂ powder or WS ₂ powder between 1 and 10% by weight have a coefficient of friction of 0.14 to 0.17, which is about 20% lower than that of the comparative example, and Al powder and MoS ₂ powder. Or it increases when the WS ₂ powder is out of the above range. On the other hand, as is clear from FIG. 2, the brush wear amount of the example brush is significantly smaller than that of the comparative brush.

[0014]

EFFECTS OF THE INVENTION According to the present invention, the proper film adjusting action of Al powder and the lubricating action of MoS ₂ powder or WS ₂ powder are combined to form a skin layer on the commutator surface of a rotating electric machine even at high speed rotation. It is possible to provide a good brush that prevents excessive wear, keeps the brush seating property good by reducing the friction coefficient, and has less brush wear.

[Brief description of drawings]

FIG. 1 is a graph showing the relationship between the amount of Al powder and / or MoS ₂ powder or WS ₂ powder added and the friction coefficient.

FIG. 2 is a graph showing the relationship between the amount of Al powder and / or MoS ₂ powder or WS ₂ powder added and the amount of brush wear.

Claims (1)

[Claims] 1. Aluminum powder 0.2 to 2% by weight and molybdenum disulfide powder or tungsten disulfide powder 1 to 10% by weight based on graphite powder and thermosetting resin which are main raw materials.
A method for producing a brush for a rotating electric machine, which comprises proportionally adding the amount of aluminum powder and the amount of molybdenum disulfide powder or tungsten disulfide powder, and mixing, molding and heat treating.