JPH0269353A - Carbon material for sliding current collection - Google Patents

Abstract

PURPOSE:To sufficiently lower electric resistance and to improve a sliding property, strength, wear resistance, and impact resistance by sintering the kneaded mixture composed of carbon aggregate, metal powder and metal fibers. CONSTITUTION:The carbon aggregate (e.g.: coal coke) of 10 to 25wt.% volatile content, 25 to 70wt.% metal fibers (e.g.: copper fibers), the metal powder (e.g.: copper powder) of 0.1 to 20wt.% by the weight of the metal fibers, and a binder (e.g.: coal tar) are kneaded and after the kneaded mixture is molded, the molding is sintered in a nitrogen atmosphere.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a carbon material for sliding current collectors mainly used in pantographs of electric vehicles.

(Prior art) Sliding current collector materials used in train pantographs, etc. have conventionally included cast alloys, sintered alloys, carbon materials, etc.
Among these materials, carbon materials have superior arc resistance and sliding properties compared to other metal-based current collecting materials, but have the drawbacks of high electrical resistance and poor strength. In order to solve this problem, sliding current collector carbon materials impregnated with molten metal or mixed with metal powder or metal fibers have been devised.

However, since the molten metal cannot penetrate into the pores inside the carbon material, the electrical resistance does not decrease sufficiently, and even when metal powder is mixed with the carbon material, the electrical resistance does not decrease sufficiently and the impact strength is also insufficient. It is enough. Additionally, carbon materials mixed with metal fibers are generally superior to carbon materials mixed with metal powders in terms of electrical resistance and strength, but it is still difficult to say that they exhibit sufficiently satisfactory performance. .

As a result of intensive studies to solve these drawbacks, the present inventors have found that by replacing some of the metal components in the carbon material mixed with metal fibers with metal powder, the carbon material can be used as a sliding current collector material. The inventors have discovered that this improves the strength of the material, and have arrived at the present invention.

That is, an object of the present invention is to provide a carbon material for a sliding current collector that has good sliding properties, sufficiently low electrical resistance, and excellent strength.

(Means for solving problems) Therefore, the object of the present invention is to provide carbon aggregate.

This can be easily achieved by using a sliding current collector carbon material formed by sintering a kneaded material containing metal powder and metal fibers in an amount of 25 wt % or more and 70 wt % or less.

(effect) The present invention will be explained in detail below.

Various types of carbon aggregates and caking agents are usually used as raw materials for sliding current collector carbon materials, but
The present invention can be applied to known combinations of the two. Specifically, carbon aggregates include coal coke, petroleum coke, pitch coke, anthracite coal, and graphite may be used in part. Coal tar as a binder
Examples include coal tar pitch, petroleum pitch, partially modified or modified products thereof, and thermosetting resins such as phenol-based 2, furfural-based, furfuryl alcohol-based, and epoxy-based, either alone or in combination. Among these, the caking material classified as a resin has a large amount of volatile matter that volatilizes during sintering, so the amount of pores in the sintered crystal increases, and it is necessary to impregnate the sintered crystal with the caking material. In order to save time for this impregnation, it is possible to use carbon aggregate with a certain amount of volatile content and reduce the amount of caking agent used depending on the amount of volatile content. The caking component in the material plays the role of a caking agent, but if carbon aggregate with too much volatile content is used,
Since a large amount of pores are generated in the aggregate itself during sintering, the volatile content is 10-25-t%, more preferably 15-20% by weight.
The amount of caking agent used may be determined depending on the amount of volatile matter in the aggregate.

The sliding current collector carbon material of the present invention contains, in addition to one or more types of carbon aggregate and caking material selected from the above specific examples, a metal powder and 25 wt% or more and 70 wt% or less, preferably 40 wt%.
It is manufactured by sintering a kneaded material containing metal fibers in an amount of % to 50 wt%.

Generally, it is known that for carbon materials containing the same amount of metal components, electrical resistance is lower and strength is higher when the metal component is metal fiber than when the metal component is metal powder.
A carbon material containing both metal fibers and metal powder, such as the carbon material for sliding current collector of the present invention, has lower electrical resistance and higher strength than a carbon material in which the entire amount of metal components contained is metal fibers. effective. Considering the effects of reducing electrical resistance and improving strength, the weight ratio of the metal powder to the metal fiber used in the present invention is about 0.1 to 20-t%, more preferably about 1 to 5 wt%. good.

Further, the type of metal for the metal powder and metal fiber is not particularly limited, but a metal with as low electrical resistance as possible is preferable, and copper is usually used industrially. Unlike iron, nickel, etc., copper is a preferable material because it does not react with carbon.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist thereof.

(Example) Self-sintering carbon powder is blended with coal-based coke that has been crushed and sieved to a particle size of 100 mesh or less in a ratio of 1 = 2, and 90% or more of the particles have a particle size of 350 mesh. Add 4wt% of the following electrolytic copper powder by internal grinding, mix for 60 minutes in a type mixer, and then add 30 parts by weight of 85°C binder pitch to 1 part of the total 1001i and heat at 200°C for 2 hours. I mixed it up.

The obtained kneaded mixture was pulverized to a size of 100 mesh or less, and then mechanically defibrated to a diameter of 100 μm and an average length of 4n+n+
47wt% of copper fiber was added by internal grinding, thoroughly mixed and crushed, the crushed product was filled into a mold, and molded at a pressure of 3 tons/c112, forming a mold with a width of 30 Illll x length of 300 mm x thickness of 20 mm. I made a body. The molded body was heated in a nitrogen atmosphere using a graphite jig at an average heating rate of 10°C/H for 10 days.
The temperature was raised to 50°C and maintained for 3 hours to produce a carbon material for sliding current collector.

A rectangular parallelepiped test piece was cut out from the carbon material, and part 2
A cross section of 0mm x 60mm has a circumferential speed of 50km/
The test piece was pressed with a force of 55N against a hard copper simulated contact wire wrapped around a disk with a diameter of 1m that was rotated in such a manner that H was rotated, and the test piece was oscillated 20 times per minute with a slide width of 50mm. A direct current of 100 A was passed between the test piece and the contact wire, and the amount of wear on the test piece per unit charge was measured. Also, using a Charpy impact tester, a 1 cm square length 6CI cut out from the carbon material
The Charpy value was measured by hitting the center part of a M square rod-shaped test piece while supporting the test piece at a distance of 1 cm from both ends.

In addition, the specific gravity and specific resistance of the carbon material were measured.

These results are shown in Table 1.

(Comparative Example 1) The results shown in Table 1 were obtained in the same manner as in the previous example except that the step of mixing copper powder and copper fibers was omitted.

(Comparative Example 2) The amount of copper powder added to the blended product of coal-based coke and self-sintering carbon powder was the total amount of copper fiber and copper powder used in the above example, except that no copper fiber was used at all. The results shown in Table 1 were obtained in the same manner as in the example.

(Comparative Example 3) Instead of adding copper fiber to 47wt%, the amount of copper fiber added was 20-[%
The results shown in Table 1 were obtained in the same manner as in the previous example except for the following.

(Comparative Example 4) &Iiii! The results shown in Table 1 were obtained in the same manner as in the previous example except that the amount of fiber used was the total amount of the copper fibers and copper powder used in the previous example, and no copper powder was used at all.

(Effects) The carbon material for sliding current collectors of the present invention exhibits performance equivalent to or better than conventional products in all aspects of electrical resistance, impact resistance, and abrasion resistance, and has particularly excellent elongation and abrasion resistance, making it practical for practical use. It is a sliding material suitable for use in industrial applications, and offers significant industrial benefits.

Claims (1)

[Claims] A carbon material for a sliding current collector obtained by sintering a kneaded material containing carbon aggregate, metal powder, and metal fibers of 25 wt% or more and 70 wt% or less.