A brush for railway electric machine and its preparation method are provided

Abstract

The invention discloses a railway electric motor brush and a preparation method thereof, belonging to the technical field of brush processing. The brush is prepared by two stages of production. One stage of production is prepared by heating and mixing carbon black, modified pitch and coal tar, roasting, and grinding to obtain a stage product after roasting is completed. Two-stage production is bymixing the first-stage product, carbon black, modified pitch and sulfur by heating, rolling, grinding, pressing, roasting, graphitizing, impregnating, finishing grinding, drilling and assembling to produce brushes. The invention also provides a preparation method of the electric brush. The performance uniformity of the electric brush is improved from 60% to 98%; The pull-out tension of the brush product can be increased by 2 to 3 times, up to 750kgf, the weight gain rate of the product is obviously increased, the weight gain rate is as high as 12%, the porosity is significantly reduced, and the porosity is up to 1%. The brush can meet the needs of the market. The brush is suitable for railway electric machines.

Description

technical field [0001] The invention relates to an electric brush for railway motors and a preparation method thereof, belonging to the technical field of electric brush processing. Background technique [0002] Motor brushes are devices that transmit energy or signals between fixed and rotating parts of rotating machinery such as railway traction motors, industrial motors, motors or generators. Also known as carbon brush. The carbon brush is made of the brush blank after post-processing and equipped with various accessories. Most of the shapes are square, set on the metal bracket, and then pressed tightly on the rotating shaft with a spring, and the upper end of the carbon brush leads to a wire. Carbon brushes vary in size. As a sliding contact, carbon brushes are widely used in many electrical equipment. [0003] In the prior art, brush production is divided into blank production and blank processing. Blank production generally uses carbon, graphite powder, and carbon ...

AI Technical Summary

Problems solved by technology

[0007] 1. Resistivity, hardness, flexural strength, and bulk density are the main indicators that determine the performance of the brush. Since the resistivity, hardness, and flexural strength are oppositely affected by the bulk density, and they are not linear, so the current production The electrical resistivity, hardness, and flexural strength of the brush are difficult to reach the ideal value, which is always unsatisfactory. At the same time, there is a fatal shortcoming: the performance is very scattered

[0008] 2. Due to the complex materials in the existing brush formula, especially the fine particle size of carbon black and graphite powder, the loose bulk density is small, the specific surface area is large, and the true specific gravity of other materials is large, so they are difficult well mixed

[0009] 3. Pressing is a key process. In order to ensure the consistency of brush performance, the pressing bulk density must be controlled within a small range. However, it is very difficult to control it with the existing pressure control method, because the pressure will vary with temperature, oil The volume, the accuracy of the pressure gauge itself, the service life and the problems of the press itself vary.

It is mainly the removal of volatile components in asphalt. During this period, the product has to go through the process of softening and coking. When softening, it is easy to deform and the scrap rate is extremely high.

[0011] 5. The existing furnace loading method will lead to great dispersion among the products after being baked, because the temperature of different points in the furnace will be different, and the products will inevitably have misalignment problems during furnace loading, which will make the products different The resistance of the position is different. When the power is turned on, the current passing through the products in different positions will be different, that is, the temperature of the products in different positions will be different, which will lead to dispersion among the products.

[0012] 6. At present, people often use alcohol-free phenolic resin as an impregnating agent to improve the performance of the brush. However, due to the limitation of the performance of the phenolic resin itself, the impregnated brush can only be used in non-oxidizing acidic media and some weak alkaline media. use

The disadvantages of this drill are low efficiency, high cost and fast wear

The hole size error of the drill bit is large, and the taper of the tapered hole cannot be guaranteed due to the change of the drill bit, resulting in uneven pulling force, frequent braid drop, and large contact resistance.

As the market is changing day by day, the pulling force and contact resistance of this kind of plugged hole can no longer meet the needs of the market.

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