JPH09291324A - Current collecting sliding material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current collecting sliding material reduced in antifriction material, such as lead and carbon, practically free from softening and melting, hardly causing arc discharge, and excellent in wear resistance. SOLUTION: A raw material, containing copper, tin, lead, and boron such as copper boride, is used and heated in an inert stmosphere under reduced pressure to melt respective components, and the resultant molten mixture is poured into a mold and cooled and solidified, by which a current collecting sliding material composed of a boron-containing cast alloy is obtained. The content of boron is regulated to 0.2-2.5 mole %. Further, powders of copper, tin and/or lead, and boric acid are used and these are mixed and then compacted and sintered by the ordinary method, by which a current collecting sliding material composed of a boron-oxide-containing sintered alloy is obtained. The content of boron oxide is regulated to 0.2-3.5 mole %. These current collecting sliding materials can be used, e.g. for pantograph shoe for railway rolling stock.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current collector / mover material made of a cast alloy containing boron or a sintered alloy containing boron oxide. The current-collecting sliding material of the present invention is excellent in wear resistance, has a high melting point, is hard to be softened and melted during use, and is a material for collecting current in electric vehicles such as railing plates for pantographs of railway vehicles and cranes. It is used as such.

[0002]

2. Description of the Related Art Current collecting and moving materials are widely used in various fields. Further, particularly when used under extremely harsh conditions such as a pantograph of a high-speed railway vehicle, higher wear resistance and the like are required. Also,
In addition to its excellent wear resistance that can withstand use at high speed for a long time, it also has good current-carrying performance, lubricity to minimize wear on the overhead line that is the object to be slid, and a machine that can withstand impacts during use. Various properties such as dynamic strength are also required.

Generally, the current collector / movement material is roughly classified into a casting alloy containing copper (Cu) and tin (Sn) as a basic component, or a sintered alloy. And, in the one made of a cast alloy, lead (Pb) is used as a main lubricant. In addition, in the case of using a sintered alloy, the wear resistance is improved by adding carbon (C) or impregnating a fat and oil component.

[0004]

However, due to the recent increase in the speed of railway vehicles and the decrease in the number of pantographs, the load applied to the pantograph contact plate has become extremely large. That is, as the speed of the railway vehicle increases, the separation between the pantograph and the overhead wire increases, and arc discharge easily occurs. Therefore, the abrasion of the contact plate due to this arc is extremely large. In addition, the number of pantographs has been reduced to 1/2 or 1/4 of that of the conventional one, which increases the amount of current collection per one sliding plate, which also causes a large amount of wear.

Therefore, there is a need for a sliding plate having more excellent wear resistance, and a sliding plate made of a current-collecting sliding material having an increased content of Pb or C, a lubricant such as an oil component is provided. Has been done. However, when the content of Pb is increased, the melting point of the material is lowered, and the material is easily softened and melted by contact with the contact wire and friction, which causes roughening of the current collecting surface. Further, when the content of C is increased, arc discharge is more likely to occur, and the current collecting surface becomes more rough.

The present invention is intended to solve the above-mentioned problems, in which a casting alloy or a sintered alloy containing Cu as a main component and Sn and Pb mixed with it contains boron (B) or boron oxide. Accordingly, it is an object of the present invention to provide a current-collecting sliding material that has excellent wear resistance and that the current-collecting surface is not easily roughened.

[0007]

The current collecting and moving material of the first invention is characterized by comprising a cast alloy containing boron or a sintered alloy containing boron oxide. The current collector / mover material of the second invention is made of a casting alloy containing copper, tin, lead and boron, and when the total number of moles of components constituting the casting alloy is 100 mol%, Boron is characterized by 0.2 to 2.5 mol%. Furthermore, the current collector / mover material of the third invention is made of a sintered alloy containing copper, at least one of tin and lead, and boron oxide, and the total number of moles of components constituting the sintered alloy is When it is 100 mol%,
The content of boron oxide is 0.2 to 3.5 mol%.

The above-mentioned "boron" usually does not exist as a free substance. In the present invention, for example, Cu containing about 2% by weight of B, so-called boron copper, can be used as a raw material. The shape, particle size, etc. of this raw material are not particularly problematic, and any material may be used. The above-mentioned "casting alloy" is a conventional method in which each component metal is treated under an inert atmosphere,
It is obtained by melting, mixing, cooling and solidifying. B is 200
Since it has a high melting point of 0 ° C. or higher, it does not melt, but directly acts on the metal and is taken into the alloy to obtain the above “current collector / movement material”.

The "sintered alloy" is obtained by mixing the powder of the base metal and the raw material powder which produces boron oxide at the time of firing, and molding and firing by a conventional method. The particle diameter of the powder of the base metal is usually preferably about 150 μm or less. Boric acid is usually used as the raw material powder for producing boron oxide. The particle size of the boric acid powder is not particularly limited, but a particle size of about several μm is generally used. It is considered that boric acid becomes the above-mentioned “boron oxide” at a temperature of about 300 ° C. during firing and forms grain boundaries between metal particles in the alloy.

In the current collector / slave material made of the cast alloy of the second invention, if B is less than 0.2 mol%, the wear resistance is not sufficiently improved. Further, when B is contained in an amount of 2.5 mol%, a current-collecting sliding material having sufficiently excellent wear resistance can be obtained, and it is not necessary to contain B in a large amount exceeding the upper limit. Boron copper and the like are considerably expensive, and it is not preferable to incorporate B in a required amount or more in terms of the cost of the current collector / movement material. This B
The content of is particularly preferably in the range of 0.3 to 1.5 mol%, and it is possible to obtain the current collector / slave material in which expensive B is minimized to the minimum and abrasion resistance is excellent.

Further, in the current collector / slave material of the second invention, as in the fourth invention, the above "tin" is 3.5 to 5.5 mol%, and the above "lead" is 0.5 to 2. It is preferably in the range of 0 mol%. If this Pb is less than 0.5 mol%, the abrasion resistance of the current collector / movement material will not be sufficiently improved. Further, in the present invention in which B is used in combination, it is possible to obtain a current collector / slave material having practical wear resistance even if Pb is not contained in a large amount exceeding 2.0 mol%. Further, when the amount of Pb is such a small amount, the melting point of the material is hardly lowered, and there is no problem that the contact surface with the overhead wire is softened or melted and the current collecting surface is roughened.

Also, the wear resistance is improved by increasing the Sn content. The larger the Pb content, the greater the effect. Therefore, especially when the Pb content is 1.0 mol% or more, the Sn content is 4.0 or less.
It is preferably at least mol%. This makes it possible to obtain a current collector / slave material having further improved wear resistance.

In the current collector / slave material made of the sintered alloy of the third invention, the wear resistance is not sufficiently improved if the content of boron oxide is less than 0.2 mol%. Moreover, if it is contained in an amount of 3.5 mol%,
A current-collecting sliding material having sufficient wear resistance can be obtained. If the content exceeds the upper limit and is contained in a large amount, the denseness of the material may decrease, the material may become brittle, and the strength may decrease. The content of this boron oxide is particularly preferably in the range of 0.5 to 2.5 mol%, and it is possible to obtain a current-collecting sliding material that is easy to fire, is dense, has high strength, and is excellent in wear resistance. .

Also in the above-mentioned current collector / slave material of the third invention, the meanings of the Sn and Pb contents and the upper and lower limits thereof are the same as in the second invention. In the third invention,
When only one of Sn and Pb, especially Sn alone, is used, the melting point of the material does not decrease, and neither softening nor melting occurs, but the abrasion resistance may not be sufficiently improved. In that case, the wear resistance can be further enhanced by increasing the content of boron oxide.

Cu, Sn and P used in the present invention
b readily forms a stable solid solution. In addition, in the present invention, in addition to the main components and boron or boron oxide, a required amount of iron, chromium, nickel, or the like may be blended for the purpose of improving conductivity, reducing arc discharge, and the like.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to Examples and Comparative Examples. Experimental Examples 1 to 13 Cu and S were made to have the composition shown in Table 1 (the balance is Cu, and the total number of moles of each component is 100 mol%).
n, Pb, Ni and boron copper (containing 2% by weight of B) were weighed, and a total amount of 600 g was melted at 1200 ° C. in a heat-resistant crucible under a reduced pressure in an argon atmosphere. afterwards,
The molten mixture was poured into a mold, cooled and solidified to obtain a cast alloy.

The shape and size of each metal and boron copper are not particularly limited. In this experimental example, Cu is a cylindrical reagent product having a diameter and a length of about 2 mm, and Sn,
As Pb and Ni, spherical ones having a diameter of about 2 to 5 mm were used. Boron copper having a diameter of 2 to 30 mm and having a spherical shape, a dish shape, or the like, which are mixed, was used.

The obtained alloy was processed into a test piece shape, and a wear test was conducted using copper as a counter material. The test conditions are as follows. The results are shown in Table 1. Testing machine; Ohkoshi type abrasion tester Friction speed; 4.39 m / sec Friction distance; 66.6 m Final load; 2.17 kgf

The dimensions of the test piece are 50 mm in length and 10 m in width.
m is a flat plate having a thickness of 5 mm. A circumferential end face of a copper disc having a diameter of 30 mm and a thickness of 3 mm was pressed at a right angle with a pressing load of 2 kgf and rotated at approximately the center of one surface of the test piece. The peripheral speed is the above-mentioned friction speed, and they were rotated in contact (pressing) until the above friction distance was reached. The pressing load was adjusted while maintaining it at 2 kgf, but at the end of the test, it was slightly above the predetermined load. The specific wear amount in Table 1 is calculated by measuring the length of the groove formed at the center of the test piece due to wear and using this length based on a predetermined calculation formula.

[0020]

[Table 1]

According to the results shown in Table 1, Pb is 1.5 mol%
In Experimental Examples 1 to 3 containing, it can be seen that the specific wear amount changes depending on the Sn content, and the specific wear amount greatly decreases as the Sn content increases. On the other hand, in Experimental Examples 4 to 12 containing 0.4 mol% of B, the Pb content was 1.
In each experimental example of 0 mol% or more, when the Sn content is particularly large, the specific wear amount is about the same as in Examples 2-3. Thus, by containing a small amount of B, P
It can be seen that even if the amount of b is considerably reduced, a current-collecting sliding material having good wear resistance can be obtained.

Further, when Pb is as small as 0.8 mol%, the specific wear amount is smaller than that of Experimental Example 1 containing 1.5 mol% Pb. The effect made is clear. In Experimental Example 13, Pb is 1
It is a conventional product containing a large amount of 0.4 mol%, and of course, its specific wear amount is small, and it is a material having excellent wear resistance. However, this material has a low melting point and may cause problems such as softening during use and roughening of the current collecting surface due to melting.

[0023]

According to the first to third aspects of the present invention, by incorporating a specific amount of B or boron oxide in the current collector / movement material, the amount of Pb or C or the like anti-friction agent is greatly reduced as compared with the conventional product. be able to. Therefore, there is almost no decrease in the melting point of the material,
Further, the occurrence of arc discharge is reduced, and a current-collecting sliding material having excellent wear resistance can be obtained. The content of Pb can be made small especially as in the fourth invention.
Since the current collector / slave material of the present invention has excellent wear resistance, it can also be used as a bearing material or the like.

Claims (4)

[Claims] 1. A current collecting and moving material comprising a cast alloy containing boron or a sintered alloy containing boron oxide. 2. A cast alloy containing copper, tin, lead and boron, wherein the boron content is 0.2 to 2. When the total number of moles of the constituents of the cast alloy is 100 mol%. A current collecting and moving material characterized by being 5 mol%. 3. A sintered alloy containing copper, at least one of tin and lead, and boron oxide, wherein the total number of moles of the components constituting the sintered alloy is 100 mol%, The current collector-moving material, wherein the content of boron oxide is 0.2 to 3.5 mol%. 4. The tin is 3.5 to 5.5 mol%,
The current collecting and moving material according to claim 2, wherein the lead is 0.5 to 2.0 mol%.