JPH02151244A - Brush for electrical rotary machine - Google Patents

Abstract

PURPOSE:To realize stabilized sliding contact by adding glass-like carbon powder into a brush for electrical rotary machine. CONSTITUTION:In case of a graphite brush, coke series artificial graphite is employed as aggregate while thermosetting resin such as phenol resin is employed as binder and carbonized thermosetting resin such as phenol resin is employed as glass-like carbon. When a brush is manufactured, aggregate carbon and binder are carbonized under a temperature higher than 700 deg.C then 5wt.% of crushed glass-like carbon powder and methanol solvent are added and mixed. Thereafter, the solvent is removed in a dryer and the remainder is subjected to crushing lower than 100 mesh thus producing powder for forming. Then the powder is pressed and baked in nitrogen gas under temperature of 700 deg.C thus producing a brush. Since glass-like carbon particles having film regulating function are dispersed uniformly in the brush, the brush can be seated well and good sliding condition can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a brush K for rotating electric machines (hereinafter referred to as a brush).

(Prior Art) In recent years, rotating electric machines have become faster and more compact, and as the circumferential speed increases, the sliding contact condition of the brushes tends to deteriorate and the contact voltage drop tends to increase. Generally, when the contact voltage drop increases, an excessive film is formed on the sliding surface of the commutator or slip ring, making the sliding contact state of the brush even more unstable.

Sparks between the brush and the commutator or slip ring become large, leading to increased wear and tear on the brush, and increased damage and wear on the commutator or slip ring.

In order to prevent the formation of an excessive film, for example, in the case of a metal graphite brush, the amount of copper powder is increased. For graphite brushes, measures such as adding abrasives are taken.

Furthermore, as shown in Japanese Patent Application Laid-Open No. 58-148642, there is a method of incorporating aluminum powder, metal phosphate, etc.

(Problem to be solved by the invention) However, in the method of increasing the amount of copper powder or adding an abrasive agent, the amount must be adjusted using a rotating electric machine, and if the amount exceeds the appropriate amount, the abrasive effect becomes large. However, there is a drawback that brush wear increases due to increased sparks due to optimization of the commutator or slip ring of the mating material.

In the method shown in Japanese Patent Application Laid-Open No. 58-148642,
The content is very small at 0.1 to 3.0% by weight,
Since the volume is small, it is difficult to uniformly disperse it in the brush material, and the film adjustment effect tends to be partially lost. In order to prevent this, increasing the amount of deposited metal impairs its participatory smoothness and increases the coefficient of wall friction.

This is undesirable because it leads to deterioration of rectification and an increase in the quality of the mating material.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and provide a brush that makes stable sliding contact.

(Means for Solving the Problems) The present invention relates to a brush containing glassy carbon powder.

The brush to which the present invention is applied is made of graphite or metal graphite. In the case of graphite brushes, the raw aggregate used is coke-based artificial graphite, pyrolytic graphite, natural graphite with low fraction, etc., and the binder is thermoset resin such as phenolic resin, melamine resin, alkyd resin, etc. Polymer resin is used. The metal powder in the case of metal graphite brushes is usually copper powder.

There are no particular restrictions on the provenance of glassy carbon.

Carbonized thermosetting resins such as ordinary phenol resins and furan resins may be used. The particle size of the glassy carbon powder is not particularly limited, but is preferably 100 mesh or less. If it is too small, the film adjustment effect will be insufficient, and if it is too large, the amount of graphite will be relatively reduced and the lubricity will be reduced.

The brush of the present invention uses the above-described raw material aggregate and binding material.

It is obtained by kneading, pulverizing, molding and firing a binder solvent and glassy carbon powder by a known method.

(Example) Next, the present invention will be explained in detail.

Example 1 N (trade name of novolac type phenolic resin manufactured by Hitachi Chemical Co., Ltd.) and Bell Pearl (trade name of split 9 granular phenolic resin manufactured by Kanebo Co., Ltd.) were carbonized at a temperature of 700°C or higher and then ground into 100 meshes or less. Contains 5% of the total weight of glassy carbon powder.

Methanol was added as a solvent and kneaded using a kneader. The solvent was then removed using an infrared dryer.

After pulverizing to 100 meshes or less, the mixture was mixed to obtain a molded powder.

Put this molding powder into a die of a powder molding press, 1.
Molded at a pressure of Ot/cI02 and molded under a nitrogen gas atmosphere at 70°C.
A brush was obtained by firing at 0°C.

Example 1 Kneading and firing were carried out in the same manner as in Example 1 except that 10% of the total weight of the glassy carbon powder in Example 1 was blended.
Brush material was obtained.

Example 3 After blending the total weight of 30 g of the glassy carbon powder in Example 1, kneading and firing were carried out in the same manner as in Example 1.
Brush material was obtained.

Example 4 Natural graphite powder, VP-11N (manufactured by Hitachi Chemical Co., Ltd.,
A resol type phenolic resin (trade name) and the glassy carbon powder used in Example 1 were blended in an amount of 15% of the total weight, and kneaded and fired in the same manner as in Example 1 to obtain a brush material.

Comparative Example 1 A brush material was obtained in the same manner as in Example 1 except that the blending ratio of the glassy carbon powder in Example 1 was 2% of the total weight.

Comparative Example 2 A brush was obtained in the same manner as in Example 1 except that the blending ratio of the glassy carbon powder in Example IK was 50% of the total weight.

Example 5 VP-11N (manufactured by Hitachi Chemical Co., Ltd., trade name of resol type phenolic resin) was cured at 200°C, and then heat-treated to 1000°C in a non-oxidizing atmosphere to obtain glassy carbon. The glassy carbon was pulverized into 100 meshes or less using an impact pulverizer, and a brush material was obtained in the same manner as in Example 1.

Comparative Example 3 A brush material was obtained in the same manner as in Example 1 except that the glassy carbon in Example 1 was not blended.

The brush material prepared in the practical row and comparative example was 6.5×115
As a result of processing the brush to X22 size and conducting a brush life test using a 100V 1kW single-phase AC commutator motor,
When the brush of the example is used, the sliding contact is stable without excessive coating, and as shown in Table 1, the rectifying spark is smaller and the brush has a longer life than the comparative example.

Table 1 1゜ 3゜ 4゜ hand calligraphy (spontaneous) table of events Show 1986 Special permission wish No. 303354 name of invention Brushes for rotating electric machines person who makes corrections Relationship with the incident Name +4451

Claims (1)

[Claims] 1. A brush for a rotating electric machine containing glassy carbon powder. 2. The brush for a rotating electrical machine according to claim 1, wherein the content of the glassy carbon powder is 5 to 30% by weight.