JPS6362852A - Ferrous sintered sliding material for current collection - Google Patents

Abstract

PURPOSE:To improve lubricity as well as wear resistance and also to reduce the attack upon a trolley wire as opposite material, by impregnating the pores of a ferrous sintered alloy, as a current-collecting sliding member, containing titanium nitride or ferrotitanium nitride with lead. CONSTITUTION:The current-collecting sliding member feeding electric power to an electric car, etc., from a trolley wire is manufactured by using as a material an ferrous sintered alloy containing 0.5-15wt%-C TiN or FeTiN and by impregnating the pores of a sliding member made of sintered alloy with Pb in an amount of 5-20pts.wt. based on 100pts.wt. of sintered alloy. In this way, the ferrous sintered sliding material for current collection excellent in electric properties and mechanical properties, also excellent as a current-collecting sliding material in lubricity as well as in wear resistance, and minimal in damage to a trolley wire can be obtained.

Description

[Detailed description of the invention] The present invention relates to a ferrous sintered current collector sliding material.

Properties required of current collector sliding materials include, for example, low aggressiveness against the mating material, the trolley wire, sufficient abrasion resistance, mechanical strength, and low electrical resistance. can be mentioned.

Especially when considering long-term maintenance and lifespan, the most important characteristic is less aggressiveness. K, which reduces aggressiveness, lowers the hardness of the material, and it is absolutely necessary that it has good lubricity. It is advantageous that the material is soft and has good lubricity, since these tend to coincide. That is, when a lubricant is added, the softer the material, the more likely the lubricant will protrude, and therefore the chance of the lubricant coming into contact with the other material increases. However, in conventional sintered alloys for current collector sliding, various metals are added to the base mainly composed of Fe or CM to improve wear resistance. Diffusion into the base is significant, and with the hardening of the material, the lubricity inevitably decreases, resulting in increased aggressiveness against the trolley wire. Furthermore, since the electrical resistance increases with the addition of metal, this method limits the amount of the element used as a lubricant to a very small 1iK, resulting in further deterioration of lubricity. Furthermore, together with the increase in electrical resistivity, these elements extremely reduce the mechanical strength, particularly the iIi impact value. Elements used as lubricants also act in the same way, so the amount added is limited by mechanical properties. In other words, metals added mainly for the purpose of improving wear resistance improve the aggressiveness of trolley wires, electrical resistivity,
This has an adverse effect on most factors such as the l1lI impact value, and this is the reason why it has conventionally been said that it is necessary to have both wear resistance and lubricity in sintered current collector sliding materials.

In view of the above-mentioned problems, the inventors of the present invention have conducted intensive research to find a current collector sliding material that has both wear resistance and lubricity. He discovered that iron-based sintered alloys containing a large amount of
No. 8490).

When a certain amount of lead is infiltrated into the pores of the iron-based sintered alloy, the wire properties required as a current collector sliding material will not deteriorate, and the aggressiveness against trolley wires will be significantly reduced. 100 parts by weight of an iron-based sintered alloy containing 0.5 to 15% by weight of nitrides and 5 to 20 parts by weight of lead.
The present invention relates to an iron-based sintered current collector sliding material characterized in that it consists of a weight part.

In the present invention, there is a method in which titanium or titanium is added after being nitrided in advance, and a method in which titanium is added during sintering. Titanium or ferrotitanium is easily nitrided, but these nitrides are stable and nitrided, and once nitrided, the nitridation does not progress to the inside easily. It is made of a very hard nitride layer and a soft interior made of pure titanium or pure Fe-O titanium. In such a nitride, the part that actually acts as an anti-wear agent is the contact interface between the thin nitride layer existing on the surface of titanium or ferrotitanium and the mating material. Therefore, the ratio of the area occupied by the titanium nitride layer and the ferrotitanium nitride layer on the sliding surface is extremely small. 1Furthermore, during sliding, these nitride layers become abrasion particles that break off and move on the sliding surface. However, since the nitride layer is very thin, at most about 2 μm, it is less likely to attack the mating material. This nitrided layer is very hard and exists on the very surface of the titanium or ferrotitanium particles with an almost uniform thickness and in the shape of an eggshell.From a microscopic perspective, it continues from the sliding surface to the inside. There is. When the product of the present invention is in a sliding state, in order for this nitride layer to wear out, a shearing stress sufficient to destroy the so-called eggshell described above is required, but this nitride layer is O
Naturally, it is tightly bonded to titanium.
It is difficult to destroy and remove it from the sliding surface. In addition, when the sliding surface of the mating material is rough, there is a risk that the so-called "chip drop phenomenon" will occur, in which the entire wear-resistant particles separate from the matrix, rather than J4 wear, in which the nitrided layer is gradually destroyed. This problem can be solved by using ferrotitanium nitride as wear-resistant particles.When ferrotitanium is nitrided, Ti, which is easily nitrided, is preferentially nitrided, and Ft
This is because, since it is not nitrided, when it is added to a matrix mainly composed of Ft, only Fz of ferrotitanium will diffuse into the matrix, and the bond will become stronger. Since titanium nitride hardly diffuses into the matrix, and the same is true for ferrotitanium as described above, the matrix itself is hardly hardened by metal solid solution. Since the thin nitride layer is used primarily as an anti-wear agent and the matrix is soft, the product of the present invention is less likely to attack the mating material. Oxides such as titania and titanium are also known to be hard materials, as is the nitride layer of titanium, but when these are used as wear-resistant particles, the entire particle is hard, so rather than breaking and wearing out, the phenomenon of "breakage" occurs. Wear caused by the flaking phenomenon is more likely to occur, and in either case, the wear powder is hard and coarse and attacks the mating material, and cannot be expected to be effective as an anti-wear agent because it cannot be bonded to the matrix.

In the present invention, it is preferable to use particles of about 100 to 200 mesh as the titanium nitride or the titanium nitride. Furthermore, since the part that actually acts as an anti-wear agent is limited to the very surface of the particle, any desired wear-resistant property can be obtained by adjusting the particle size. The amount of titanium and/or free titanium is approximately 0.5 to 15% in the sintered alloy.
Heavy weight percentage is preferred. In this range, sufficient wear resistance, lubricity, and mechanical strength can be obtained.

It is necessary to infiltrate gold with lead. By infiltrating lead, the lead enters into the pores of the sintered alloy and is retained, thereby improving the plate characteristics of the YIi sliding material and, in particular, reducing the wear of the trolley wire.

Lead Impregnation Co., Ltd. uses 5 to 2 parts by weight of the sintered alloy containing titanium nitride or ferrotitanium nitride as described above.
It is appropriate to use a 0-fold ffi section.

If the amount of lead is less than 5 parts by weight, the effect of reducing wear on the trolley wire will be insufficient, while if it exceeds 20 parts by weight, the abrasion resistance and mechanical properties of the current collector sliding material will deteriorate, which is not preferable.

The sintered current collector sliding material of the present invention is characterized by infiltrating the sintered alloy containing titanium nitride and/or titanium nitride with lead, and other configurations are normal. It can be the same as the sintered current collector sliding material. Therefore, Ft or Ftt-based alloys can be used as the usual base component. Further, in the present invention, metals and the like that are normally added to sintered current collector sliding materials can be added to the material with the minimum amount necessary to maintain the mechanical properties and electrical properties at predetermined values.

Examples of these metals include Ni, Mσ, Cm,
Fz.

Typical examples of metals such as Cr, P and alloys of these metals include LTE, FtMo, FtCr, CmCr, etc., and at least one of these can be added. However, in the present invention, it is possible to reduce the amount of these metals compared to conventional ones, and it is particularly preferable to use them usually in the range of about 0.8 to 1Qm/%. WS2. as necessary. MρS2
°C (graphite), lubricants such as boron nitride, Ha,
Antiwear agents such as Cr, Fgets, Ftcr, etc. can also be added.

In order to obtain the sintered current collector sliding material of the present invention, first, titanium and/or ferrotitanium is added to a mixture of the base component, metal component, and other additives as necessary, after being nitrided in advance, and then molded. or by adding the titanium and/or ferrotitanium untreated and sintering it in an atmosphere containing nitrogen or ferrotitanium during the sintering. A sintered alloy is formed by nitriding ferrotitanium. To carry out the nitriding treatment, as mentioned above, use nitrogen gas, a mixture of nitrogen and hydrogen, anhydrogen gas, anhydrogen decomposition gas, etc. in a neutral or reducing atmosphere containing purple or anhydrogen. It is preferable to heat at about 600 to 1800°C in an atmosphere. Molding is approximately 2.5-7.51 an/cd.

Sintering is usually preferably carried out at a temperature of about 750-1300°C. When nitriding is performed at the same time, the sintering must be performed in an atmosphere containing nitrogen or annealing gas, but when using pre-nitrided titanium and/or untreated titanium, the same atmosphere as above must be used. However, in addition to this, sintering may be performed in a gas such as alcone, hydrogen, or helium, or in a vacuum atmosphere.

Next, the current collector sliding material of the present invention is obtained by infiltrating the obtained sintered alloy with a predetermined amount of lead. As for the infiltration method, for example, a lead piece of a predetermined weight is placed on the sintered alloy and heated to 1000 to 1100°C in a reducing or neutral atmosphere to infiltrate the lead into the pores of the sintered alloy. Just let it happen.

In the sintered current collector sliding material of the present invention obtained as described above, the hardness of one matrix can be any value higher than that of pure iron sintered material, but the mechanical strength, lubricity,
Considering various requirements such as aggressiveness to mating material (for example, trolley wire), a Purinel hardness of about 50 to 95, particularly about 60 to 80 is preferred. In these hardness ranges, the added lubricant can sufficiently exhibit its effect.

The current collector sliding material of the present invention has excellent mechanical strength, electrical properties, etc., and also has good wear resistance and lubricity, and is particularly less aggressive against the mating material, the trolley wire.

The present invention will be described in detail below with reference to Examples.

Example 1 Table 1 shows the composition of the sintered current collector sliding material. In addition, F in the table
tTi-N and Ti-N are nitrides produced by holding pzTi or Ti at 1000° C. for 1 hour in an annealer.

The components listed in Table 1 (excluding Ph) were mixed, molded at 6 to 7 tons/Cd, and sintered at 1120° C. for 90 minutes in annealy cracked gas to obtain a sintered alloy. Invention products 1 to 7
For this, a predetermined amount of lead pieces was placed on the obtained sintered alloy, and heated at 1080°C for 90 minutes in an atmosphere of acitonia decomposition gas to infiltrate lead into the sintered alloy. I let it happen.

Table 1 The physical properties of the nine current collector sliding materials obtained are shown in Table 2, and the results of the wear resistance test are shown in Table 8.

The wear test was carried out using the obtained shim board material with dimensions of 1° x 25 x
A length of 90 m was cut out and used as a test piece for N collecting sliding wear. Test conditions are pressing force 5kg/d, current FiAC (21F)
100A, sliding speed ti 100 KM/, and test time 5 minutes. The mating trolley wire was made of hard copper wire, and had an overhead wire structure with a diameter of 8851M and a winding contact surface with a width of 6ff. In this case, the eccentricity of the sushi board is 10
ff, similar to the usage conditions of pantographs on trains.

The evaluation of the sample surface condition and trolley surface condition is as follows.

◎ Very good O Good Δ Slightly poor has good electrical properties and mechanical strength,
When used as a current collector sliding material, it has excellent wear resistance and is less likely to damage the trolley wire.

(The above) Agent: Patent attorney Eiji Saegusa, ゛・１
614. ．． 1

Claims (1)

[Claims] (1) Zero titanium nitride and/or ferrotitanium nitride
．． An iron-based sintered current collector sliding material comprising 100 parts by weight of an iron-based sintered alloy containing 5 to 15% by weight and 5 to 20 parts by weight of lead.