JPH09316576A - Current collector shoe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a lightweight current collector shoe, excellent in property of following trolley wire up and minimal in wear by arc, by compounding specific amounts of one or more kinds of materials among ceramic fibers, ceramic whiskers, and ceramic grains and specific amounts of carbon fibers coated with an element alloyable with aluminum, with an aluminum (alloy) matrix. SOLUTION: Ceramic fibers, etc., are compounded with an aluminum (alloy) matrix by 4-35vol.%. Further, carbon fibers are compounded by 4-20vol.%. Because of its hardness, the ceramic material to be dispersed, such as ceramic fibers, has a function of improving the wear resistance of a shoe. Sufficient wear resistance cannot be obtained when its content is less than 4%, and, when it exceeds 35%, the wear of a working tool is increased and the toughness of a shoe is deteriorated. The readhesion of aluminum melt occurring at the time of arc discharge can be prevented by the lubricity of the carbon fibers; however, when the content of the carbon fibers exceeds 20%, the hardness of a shoe is deteriorated and wear amount is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding plate for a current collector which is less likely to be worn by an arc, has excellent wear resistance, suppresses wear of a trolley wire, has stable strength at a high level, and can be manufactured with a high yield.

[0002]

2. Description of the Related Art A sliding plate for a current collector is required to have mechanical properties such as toughness, electrical conductivity, wear resistance, arc resistance, and trolley wire non-aggressiveness. A sliding plate is used. In recent years, as the speed of vehicles has increased, the frequency of derailment of the sliding plate has increased, resulting in frequent arcing, increasing the amount of wear of the sliding plate and the trolley wire, and causing radio interference. Therefore, in order to prevent disconnection, the sliding plate is required to follow the trolley wire, and a sliding plate made of an aluminum composite material has been proposed (Japanese Patent Laid-Open No. 3-86002). This sliding plate is made by dispersing ceramic fibers or the like in an aluminum matrix and is lightweight, and therefore has good followability to the trolley wire. However, since aluminum has a low melting point, there is a problem that when an arc occurs, aluminum melts and adheres to the sliding plate, and this adhered matter causes the trolley wire to wear (roughly damage) early. Therefore, in addition to the ceramic dispersion material, a sliding plate in which carbon fibers having excellent lubricity are dispersed has been proposed (JP-A-6-234061). In this sliding plate, the poor wettability of the carbon fibers with the molten aluminum prevents the re-adhesion of the molten aluminum to the sliding plate when an arc occurs, and prevents the trolley wire from being damaged. The sliding plate is
Usually, it is manufactured by a pressure casting method in which a ceramic fiber and a carbon fiber are formed into a preform (a porous fiber molded body) and a molten aluminum is pressurized and injected into the preform.

[0003]

However, since the sliding plate manufactured by this pressure casting method has poor wettability of carbon fibers, the distribution of the fibers becomes non-uniform, resulting in abrasion resistance, impact strength and the like. There was a problem that the quality was not stable.

[0004]

[Means for Solving the Problems] If carbon fibers are coated with a metal that can be alloyed with molten aluminum and an alloy layer is formed at the interface between aluminum and carbon fibers to improve the wettability of both, the sliding It is possible to stabilize the required quality of the plate at a high level. According to the present invention, a matrix of aluminum or aluminum alloy is coated with one or more of ceramic fibers, ceramic whiskers, or ceramic particles in a total amount of 4 to 35 vol% and an element capable of being alloyed with aluminum. The present invention provides a sliding plate for a current collector in which 4 to 20 vol% of carbon fibers are combined.

In particular, since the surface of the carbon fiber is coated with an element capable of alloying with aluminum, the bonding strength at the interface between the aluminum and the carbon fiber is increased and the distribution of the fiber is equalized, resulting in wear resistance. And impact strength are improved, and variations are reduced.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, any aluminum-based material having conductivity such as pure aluminum, Al-Mg-based alloy, and Al-Si-based alloy is applied to the matrix.

In the present invention, dispersed in the matrix
Wear resistance of sliding plate due to hard ceramic dispersion material
Improve. Dispersion amount of ceramic dispersion material is 4-35vol%
The reason why it is limited to 4 vol% is that sufficient wear resistance can be obtained.
If it exceeds 35 vol%, the effect will be saturated and
Wear of the tool for machining the steel plate becomes severe, and the toughness of the sliding plate is low.
This is because they will come down. In the ceramic dispersion material
Is ceramic fiber, ceramic particles, ceramic
One type or two or more types such as scars are used. The ceramic
The material of the dispersion material is TiC, ZrC, HfC, VC, NbC,
TaC, Cr_ThreeC _Two , WC, SiC, B_FourCarbides such as C and MoC, TiN
 , ZrN, TaN, Si_ThreeN_Four, BN, VN, NbN and other nitrides, TiB
_Two, ZrB_Two, NbB_Two, TaB_Two, CrB, WB, LaB₆Boride, etc., M
gO, Al_TwoO_Three, SiO_Two, Cr_TwoO_Three, Y_TwoO_ThreeUsed with oxides, etc.
it can.

In the present invention, the carbon fiber has a function of preventing re-adhesion of the aluminum melt generated during arc discharge. The reason why the dispersion amount of carbon fiber is limited to 4 to 20 vol% is that the effect is not sufficiently obtained if it is less than 4 vol%,
This is because not only is the effect saturated, but also the hardness of the sliding plate decreases and the amount of wear increases. Carbon fiber,
It is possible to use a milled fiber obtained by grinding and shortening carbon fiber, a chopped fiber obtained by cutting carbon fiber into a short length, a short carbon fiber produced as a short fiber from the beginning, and the like.

The element that coats the carbon fiber is an element that can be alloyed with aluminum and is, for example, Cu, Ni, Cr or the like. Since these elements (metals) are alloyed with aluminum, the interface strength between the carbon fibers and the matrix is improved, and the strength of the entire sliding plate is improved. PVD, CVD, sputtering, or the like can be applied to coat the carbon fiber with a metal such as Cu, Ni, or Cr. You may use a commercial item. If the coating thickness is less than 30 μm, the coating may peel off, and improvement in interfacial strength cannot be expected so much. Coating thickness is 100
If it exceeds μm, the effect is saturated and it is uneconomical. Therefore, the coating thickness is preferably 30-100 μm.

[0010]

The present invention will be described below in detail with reference to examples. (Example 1) Alumina fiber (diameter 3 to 5 μm, length about 5)
00 μm) and either Cu, Ni, or Cr 35 μm
Carbon fiber with a thickness of 3 to 10 μm (length 3 to 10 μm)
10 mm) to prepare a preform, and the preform was set in a slide plate-shaped cavity of a high-pressure casting mold, and the molten aluminum alloy was injected therein. Then, the molten metal was pressed and impregnated into the preform to produce a sliding plate made of a near net shape aluminum composite material. The mixing ratio and content of the alumina fiber and the carbon fiber were variously changed. JIS-4032 alloy (Al
-Si-Fe-Cu-Mg system) was used.

A large number (n = 20) of the sliding plates were manufactured and subjected to a current collection abrasion test and a Charpy impact test. The current collecting abrasion test was performed by pressing the test piece against a rotary trolley wire (hard copper) having a width of 10 mm that rotates at a peripheral speed of 100 km / hr. Pressing load is 2 kg
f, energizing current was set to 100 A, and test time was set to 1 hour. The abrasion test of the trolley wire with the sliding plate was performed by mounting the sliding plate on a pantograph and measuring the wear depth of the trolley wire after the sliding plate passed 10 ⁴ times. The result of the Charpy impact test is shown as a non-defective product (yield ratio) when the test value is 0.3 kgf · m / cm ² or more. The results are shown in Table 1.

[0012]

[Table 1] Ceramic / carbon / matrix: Ceramic fiber / carbon fiber / Al matrix. Coating metal on carbon fiber and its thickness.

As is clear from Table 1, the products of the present invention (N
In all of o.1 to 8), the abrasion amount of the sliding plate and the trolley wire (hard copper) was smaller than that of the conventional product (No.12, 13). Also, in the impact test, most of them cleared the prescribed strength and showed a high yield rate. On the other hand, in Comparative Example No. 9, the wear amount (volume) of the sliding plate increased because the amount of alumina short fibers was small. N
In o.10, since the carbon fiber was small, the melted material during arc melting adhered to the sliding plate and the wear rate of the trolley wire increased. No.11
Since the carbon fiber was not coated with a metal, the interfacial strength between aluminum and the carbon fiber was low, a sliding plate having a predetermined strength could not be stably obtained, and the non-defective rate decreased.

The sliding plate of the present invention had a specific gravity of 2.2 to 2.66 and was sufficiently lightweight. Also the resistivity is 8 ~
It had a conductivity in the range of 17 μΩ · cm and was equal to or higher than that of conventional materials.

[0015]

As described above, the sliding plate for the current collector of the present invention is lightweight, has excellent followability to the trolley wire, has little wear due to arc, and has a hard ceramic dispersion material and excellent wear resistance. Since the carbon fibers are rich in lubricity, the aluminum melt does not redeposit on the contact plate and wear of the trolley wire is suppressed. Moreover, since the carbon fiber is coated with an element that can be alloyed with aluminum, an alloy layer is formed at the interface between the aluminum and the carbon fiber to enhance the bondability between the two and improve the wear resistance and impact strength of the sliding plate. It is stable and the rate of non-defective products is improved.

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location C22C 1/09 C22C 1/09 G 1/10 1/10 F (72) Inventor Shoichi Sakoda Chiyoda-ku, Tokyo Marunouchi 2-6-1 No. 1 Furukawa Electric Co., Ltd. (72) Inventor Shinsaku Matsuyama 1 338 Kamisakuyanagi, Yamato-shi, Kanagawa Prefecture Toyo Denki Seizo Co., Ltd. (72) Inventor Takehiko Akabaka Yamato-shi, Kanagawa 338 Kamigusayanagi 1 Toyo Denki Seizo Co., Ltd. Technical Research Center

Claims (1)

[Claims] 1. A matrix of aluminum or aluminum alloy is coated with a total of 4 to 35 vol% of one or more of ceramic fibers, ceramic whiskers, or ceramic particles, and an element capable of alloying with aluminum. A sliding plate for a current collector in which each of the prepared carbon fibers is compounded in an amount of 4 to 20 vol%.