JPH0390440A - Copper-covered steel trolley wire - Google Patents

Abstract

PURPOSE:To improve the conductivity and strength and to facilitate the detection of a friction limit by a method wherein the covering rate of a covering material formed of a copper or a copper alloy is set to a value within a specified numerical value range in a sectional area ratio, and a core formed of a steel wire and the covering material are combined together by using a metal. CONSTITUTION:A trolley wire is formed such that the periphery of a core material 1 is covered in an uniform thickness with a covering material 2 formed of copper or a copper alloy. A pair of V-shaped grooves 3 extended longitudinally of the trolley wire are formed in the peripheral surface of the covering material 2. By grasping the groove 3 by means of a mounting metal, the trolley wire is suspended. In this case. the covering rate of the covering material 2 is set to 77-85% in a sectional area ratio (a ratio of the area of the covering material 2 to the sectional area of the whole of the trolley wire). The steel wire of the core material 1 and the copper or the copper alloy region of the covering material 2 are combined with each other by means of a metal. This constitution provides the trolley wire which increases conductivity, provides enough strength, and facilitates the detection of a friction limit.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a copper-coated steel contact wire that has a core material of steel wire and is coated around the core material with copper or a copper alloy. The present invention also relates to a copper-coated steel contact wire which has high tensile strength and whose wear limit can be easily detected.

[Prior Art] A copper wire or a copper alloy wire is usually used as a railway contact wire. By the way, trains usually operate at a speed of 130 per hour.
km, but this traveling speed can be expressed as, for example, IGOk per hour.
Recently, there has been a strong demand for high-speed train operation, such as increasing the speed of trains to +*, and for this reason, there is a need to further increase the strength of contact wires.

In other words, in order to increase the operating speed of trains, it is necessary to increase the wave propagation speed of the contact wire.

In this case, the wave propagation speed C is expressed by the following formula.

C=F7T However, T is the overhead wire tension, and ρ is the linear density (weight per unit length) of the contact wire.

As is clear from this equation, in order to increase the wave propagation speed C, it is necessary to increase the tension T or decrease the linear density ρ. Therefore, as a technique to reduce the linear density ρ and increase the propagation speed C, an aluminum composite contact wire in which a steel wire is coated with aluminum and crimped is proposed.

Further, it is desirable that the contact wire has high strength and conductivity. This is why copper or copper alloy wires have conventionally been used as contact wires. By the way, since the pantograph slides on the contact wire at high speed, the contact wire is subject to significant wear. For this reason, it is necessary to periodically monitor the degree of wear of the contact wire and replace it when the wire has become thinner to a predetermined diameter, or in other words, when the wire diameter remains. It is. Therefore, since it is necessary to extend the service life of the contact wire and increase the interval between replacements, it is desired that the contact wire has excellent wear resistance. The inventors of the present application proposed a copper-coated steel contact wire as a contact wire having extremely excellent strength and wear resistance (Japanese Patent Laid-Open No. 16447/1983).

[Problems to be Solved by the Invention] However, these conventional contact wires have the following drawbacks.

First, in aluminum composite contact wires, since the contact wire attachment fittings are made of a prepared alloy, there is a problem in that the copper alloy of the attachment fittings comes into contact with the aluminum coating layer of the contact wire, resulting in contact corrosion.

In order to avoid this corrosion, it is necessary to change all the currently popular mounting brackets to materials that do not cause contact corrosion with aluminum, which is not practical in terms of cost.

On the other hand, although the strength and wear resistance of copper-coated steel contact wires have been significantly improved, the copper coverage is as low as 45 to 75%, resulting in a conductivity of less than 80% at most. Even if the conductivity is low, there is no problem if the train is running on an AC section, but in the case of a DC section, low conductivity will significantly reduce current efficiency, so contact wires with high conductivity may be used. It is desirable to install overhead lines.

Furthermore, as mentioned above, the contact wire is replaced when the wire diameter decreases to the wear limit when the remaining diameter reaches a predetermined value, but in order to detect the wear limit, an optical wire diameter measuring device is used. It is necessary to measure the diameter of the wire over the entire length of the overhead wire manually, for example, at night using a machine, and this must be done periodically, which is extremely complicated work. Therefore, it is desired to improve the detection of this wear limit.

The present invention has been made in view of such problems, and includes:
Copper-coated steel that uses copper or copper alloy as the coating material that does not cause contact corrosion with the mounting hardware, has high conductivity, has sufficient strength, and can easily detect the wear limit. The purpose is to provide contact wires.

[Means for Solving the Problems] A copper-coated steel contact wire according to the present invention is a copper-coated steel contact wire in which a steel wire is used as a core material and the core material is coated with copper or a copper alloy. The covering material made of a copper alloy has a coverage ratio of 77 to 85% in terms of cross-sectional area ratio, and the core material and the covering material are metallically bonded.

[Function] In the present invention, by using steel wire as the core material,
It is possible to increase the strength, thereby increasing the speed of train operation.

Further, since the core material is covered with a covering material made of copper or a copper alloy, contact corrosion between the copper alloy and the split fitting is prevented, and the required conductivity as a contact wire is ensured.

Further, in the present invention, since the steel wire core material and the copper or copper alloy region of the sheathing material are metallically bonded, corrosion is prevented from progressing at the boundary between the two.

[Example] Hereinafter, an example of the present invention will be specifically described with reference to the accompanying drawings.

FIG. 1 is a diametrical cross-sectional view of a copper-coated steel contact wire according to an embodiment of the present invention. This contact wire has a core material 1 made of steel wire at its center, and a covering material 2 around the core material 1.
is coated with a substantially uniform thickness. The covering material 2 is made of copper or a copper alloy, and a pair of V-shaped grooves 3 extending in the longitudinal direction of the contact wire are formed on the circumferential surface of the covering material 2. The contact wire is suspended by gripping this groove 3 with a fitting.

The reason why steel wire was used as the core material 1 was to increase the strength of the contact wire. Further, steel wire has the advantage of being economically inexpensive and easily available.

Since steel wire is thus used as the core material, the contact wire has high strength and high conductivity.

Since the contact wire has such high strength, the overhead wire tension T can be set high. Therefore, as described above, the wave propagation speed C can be increased, making it possible to increase the speed of the train.

The reason why copper or a copper alloy is used as the covering material 2 is to ensure the conductivity required for a contact wire and to prevent contact corrosion with a mounting metal fitting made of a prepared alloy.

In this case, in order to avoid a decrease in current efficiency in the DC section, the conductivity needs to be 80% lAC3 or more. In addition, in order to realize high-speed train operation, the tension of the overhead wire must be 1200 kgf or more, and for this purpose, the tensile load must be 3000 kgf at the wear limit, and the tensile load must be 4500 kgf or more at the beginning of use. It is necessary.

In order to achieve this purpose, the coverage ratio of the copper or copper alloy coating material in the copper-coated copper composite wire should be 77 to 85% in terms of cross-sectional area ratio (ratio of the area of the coating material to the cross-sectional area of the entire contact wire). It is necessary to

When the coverage rate of the copper or copper alloy coating material is less than 77%, the portion of the copper or copper alloy having high conductivity decreases, and the conductivity of the composite wire cannot be increased to 80% or more.

On the other hand, when the coverage exceeds 85%, the steel wire core material portion decreases and the strength is insufficient, making it impossible to obtain a tensile load of 45QOkgf or more.

In addition, conventional copper-coated steel contact wires have a copper or copper alloy coating material coverage of 45 to 75%, so even if the steel wire core material is exposed, the diameter of the remaining portion is large, so it is still difficult to use contact wires. The wear limit has not yet been reached. For this reason, it continues to be used even when the core material is exposed. However, in the present invention, since the coverage rate of the copper or copper alloy covering material is as high as 77 to 85%, when the steel wire core material is exposed, the wire diameter of the remaining portion is small and it becomes necessary to re-cover the wire. In other words, when the wear progresses during use as a contact wire, the wear limit is reached just at the time when the steel wire core material is exposed.

Therefore, in the present invention, it is possible to detect that the wear limit has been reached by detecting the exposure of the steel wire core material portion. This exposure of the steel wire can be sufficiently detected with the naked eye, and there is no need to use a large-scale device such as an optical measuring device as in the past, which significantly improves work efficiency. However, when the coverage of the copper or copper alloy coating material exceeds 85%, the exposed steel wire cannot be used as an indicator of the wear limit. In this respect as well, the coverage needs to be 85% or less.

Further, since the copper-coated steel contact wire is coated with a copper or copper alloy covering material 2 at a predetermined coverage rate, this covering material 2 comes into contact with the mounting bracket for suspending the contact wire. Therefore,
No contact corrosion occurs with copper alloy fittings.

The present invention is characterized in that the steel wire of the core material 1 and the copper or copper alloy region of the covering material 2 are metallurgically bonded. Composite wires having such metallic bonds can be produced, for example, by dipping steel wires into molten copper or molten steel alloys to obtain copper-coated cast steel wires using the so-called dip forming method. It can be manufactured by hot rolling a cast wire. Note that the thickness of the covering material 2 can be adjusted by adjusting the immersion time of the steel wire in the molten steel.

In a composite wire having this metallic bond, atoms diffuse at the interface between the steel wire and the copper or copper alloy region, resulting in an extremely strong bond. Therefore, for example, even when a compressive load is applied to this composite wire in its diametrical direction, no separation occurs between the steel wire and the copper or copper alloy region. This also applies when the composite wire is tensilely broken or subjected to bending deformation.

Therefore, as shown in Fig. 2, even if the contact wire is worn and the core material 1 of the steel wire is exposed, water etc. will not enter the boundary between the copper or copper alloy sheathing material 2 and the core material L. Never. Therefore, this boundary portion is not preferentially corroded.

Further, as shown in FIG. 2, when the contact wire is worn and the steel wire core material 1 is exposed, the contact wire is replaced with a new one, so FIG. 2 shows the wear limit of the contact wire. In this way, since wear can be detected by exposing the steel wire, the wear limit can be confirmed simply by visual inspection. Unlike conventional contact wires, this example does not require the troublesome work of measuring the wire diameter. There is no.

Next, the results of manufacturing and testing the characteristics of copper-coated steel contact wires according to examples of the present invention will be described together with the results of testing the characteristics of contact wires according to comparative examples and conventional examples. The contact wire according to the embodiment of the present invention has a JIS core steel wire.
o 3505, and manufactured as shown below. First, this steel wire was coated with copper or copper alloy by the dip forming method described above to produce a cast wire with a diameter of 20 s+m. Thereafter, this cast wire was rolled into a wire rod with a diameter of 17 mm, and further with a diameter of 13.1 mm.
After drawing the wire into a mm-thick wire, it was cut into grooves. Then, by finishing wire drawing, it has the cross-sectional shape shown in Fig. 1,
A contact wire having a cross-sectional area of 110i112 was obtained.

The conductivity, tensile load, wear limit load, wear limit conductor resistance, overhead wire tension, and wave propagation speed were measured for each of these contact wires, and the results are shown in Table 1 below.

Table 1 Contact wires having various coverage ratios shown in Table 1 were manufactured by varying the immersion time in the molten metal. Further, the conventional example is a characteristic of a pure copper contact wire.

As shown in Table 1, in the cases of Examples 1 to 3, the electrical conductivity is 80% or more, and in addition to having sufficient electrical conductivity, the tensile load is high at 4500 kgf or more. The overhead wire tension can be increased to 1200 kgf or more.

On the other hand, although conventional copper wire contact wires have high conductivity, their tensile load is low, so the overhead wire tension is as low as 100,100O. Therefore, the contact wires of Examples 1 to 3 have wave propagation speeds that are 1.10 times or more higher than those of conventional copper contact wires, and can increase the operating speed of trains.

In addition, although the above embodiment concerns a contact wire with a cross-sectional area of 110-, it is of course possible to apply the present invention to other types of contact wires such as those with a cross-sectional area of 170-.

[Effects of the Invention] According to the present invention, the steel wire core material has a composite structure in which a copper or copper alloy covering material with a coverage ratio of 77 to 85% in cross-sectional area ratio is metallically bonded, so that sufficient strength and high A contact wire having corrosion resistance and extremely high electrical conductivity of 80% IACS or higher can be obtained. Therefore, this contact wire can be applied to DC sections. Additionally, this contact wire can be installed using the existing mounting hardware as is. Furthermore, since this contact wire has high strength, the tension of the overhead wire can be increased, thereby increasing the wave propagation speed. This makes it possible to run trains at higher speeds than before. Furthermore, since the core material and the covering material are joined by metal bonding, the joining strength is high, and even if bending stress or the like is applied to the contact wire, the covering material will not separate from the core material at this joining interface. Even if this joint interface is exposed due to wear, water and the like are prevented from entering and corrosion does not occur.

Furthermore, since the exposure of the steel wire can be used as an index of the wear limit, it is possible to omit the wire diameter measurement work for determining the wear limit.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a copper-coated steel contact wire according to an embodiment of the present invention, and FIG. 2 is a sectional view of the contact wire after wear. 1; Core material, 2; Covering material, 3; Groove

Claims (1)

[Claims] (1) In a copper-coated steel contact wire in which a steel wire is used as a core material and the core material is coated with copper or copper alloy, the coating material made of copper or copper alloy has a coverage of 77 to 85% in terms of cross-sectional area ratio. 1. A copper-coated steel contact wire, characterized in that the core material and the covering material are metallurgically bonded.