JPH097724A - Joining method for electric cable by explosion of explosive compound - Google Patents

Abstract

PURPOSE: To provide the joining method for joining electric cables not by mechanical compression or squeezing effects but by a metallurgical junction joining not only the parts exposed outside of the stranded cables but also their inner layer parts without giving any damage to the cables. CONSTITUTION: This is the joining method where a protective body 5 made of metal in the same system with the material consisting of the outer layers of stranded cables while being formed into a pipelike curved surface in advance, is covered over the outer circumference of the electric cables 7 to be joined, and a flying plate 3 is disposed at the outer sides of the electric cables, which is made of metal identical to the material of the protective body 5, files in by the explosive pressure of explosives 1 which explode at a speed equal to or more than 70% of the sound speed of the metal so as to be hit against the protective body 5, and the flying plate 3, the protective body 5 and the electric cables 7 are thereby integrally and metallurgically joined. The explosives 1 are set at the outer side of the curved surface of the flying plate 3, let explosion progress from one end of the explosives 1 to the other end progressively, and it is so designed that the moving speed of a point by explosion where the flying plate 3 is hit against the protective body 5, is less than 70% of the sound speed of the metal at the outer layer of the electric cables to be joined, and the flying speed of a flying tube in the direction perpendicuklrly intersected with the progressing direction of explosion, is sufficient enough to join the stranded cable themselves in the inner layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for joining a transmission / distribution line by the explosive pressure of an explosive, and in particular, by metallurgically joining a metal plate, a protective tube and an electric wire together, a high strength with a small amount of explosive. It is a method of obtaining a highly reliable joint with excellent weather resistance, and can be implemented even in remote areas of the mountains where it is difficult to use power such as electric power and machinery, and since the amount of explosive used is small, a lightweight explosion-proof silencer can be used. It is a method that can be used and can be easily implemented without pollution of explosion noise even in areas with many houses.

[0002]

2. Description of the Related Art In the conventional method of joining transmission and distribution lines by the explosive pressure of explosives, the ends of the lines to be joined are butted against each other in a metal pipe, and the outside of the metal pipe is thick (about 10 mm) rubber or the like. Wrap the detonating wire over the elastic protective body of
By detonating the detonating wire, the metal tube is contracted and the electric wire is mechanically compressed to join the electric wires. As a patent document of the prior art, there are gazettes of Japanese Examined Patent Publication No. 51-25592, Japanese Utility Model No. 58-32865 and the like.

According to this method, the detonating speed of the detonating wire is higher than or substantially equal to the sound speed of the metal used for the electric wire, and in such a case, it is known that the metal cannot be metallurgically joined by the detoning pressure. Has been. In addition, by covering the outside of the metal tube with an elastic protective body such as thick rubber and winding a detonating wire around it, the elastic protective body attenuates the explosion pressure transmitted to the metal tube. The need to use detonators results in more explosive charge than is needed to simply compress and join metal tubes.

Further, since such joining by mechanical compression or caulking has a joining strength lower than that of metallurgical joining, it is necessary to make the joining portion of the electric wire large in length, and this is also a detonation. This was one of the factors that increased the amount of wire used. In addition, mechanically tightening the metal pipe and joining it with compression or caulking stress has the problem of low reliability, and rainwater or corrosive gas in the gap between the metal pipe and the wire or the twisted wire of the wire. Since the metal is subjected to strong working due to the strong pressure of the explosion, the part joined by such a method contains a large residual stress and is eroded more easily than other parts. there were.

[0005]

Problems to be Solved by the Invention In order to eliminate the drawbacks of the above-mentioned conventional method of joining electric wires due to the explosion of explosives, there were the following problems. (1) In order to prevent rainwater and gas from entering the joints, the joints should be metallurgically joined to the inside of the flight tube, the protection tube and the stranded wire without using mechanical compression or caulking, and between the stranded wires. It is necessary to close the voids of the and prevent them from entering. For this purpose, it is necessary to use explosives having an explosive velocity lower than that of the detonating fuse and thus a low explosive pressure, which may increase the amount of explosives used. (2) If a thick protective layer is not provided between the explosive and the metal tube in order to reduce the amount of the explosive used, the metal tube or the electric wire for joining may be damaged by the explosion pressure. (3) A strong explosive force is required to join even the twisted wires in the inner layer of the wire, and as a result, if the flight tube collides directly with the wire and is attempted to join, the wire may be greatly deformed or, in some cases, broken. There is. (4) Conventionally, in metallurgically joining metals with a high explosive velocity, for example, when two metal plates are to be joined by explosion, an angle is given between the metal plates so that the metal plates collide with each other. The moving speed of the point was set so as not to exceed the speed of sound of the metal. On the other hand, when trying to join metal around a rod-shaped object such as an electric wire, the method conventionally considered is
Install a tapered metal tube around the rod-shaped joining target,
By exploding the explosive covering the outer circumference of the metal tube from one end of the tapered side, it was thought that the speed of the collision point of the metal tube and the rod-shaped object to be bonded was made slower than the explosion speed, and the metal tube was bonded. It was not suitable for practical use due to problems such as difficulty in making a seamless tapered tube. As a result of conducting many theoretical and experimental studies on these problems, the inventors have reached the following conclusions.

[0006]

[Means for Solving the Problem] It is considered that the above problems can be solved by taking the following measures. Each number corresponds to the above-mentioned problem number. (1) When it becomes possible to metallurgically bond the metal plate, the protective tube, and the stranded wires in the inner layer of the wire, the strength of the joint has the original strength of the metal forming the joint or higher. It has much higher strength than the conventional method of joining by explosive joining, which does not involve metallurgical joining and mechanical joining or crimping. Therefore, in the conventional method, the strength is ensured by providing the joint portion having a wire length of, for example, 300 mm or 500 mm, but the strength is secured by the joint method, for example, 100 mm or less, while securing the strength or more by the conventional joining method. By reducing the joint length, the amount of explosive is reduced to below the conventional level.
As will be described in detail in the next section, the amount of explosive charge can be reduced by eliminating the thick protective layer of an elastic body to prevent the explosion pressure transmitted to the joint from being attenuated.

(2) When the amount of explosive is reduced by eliminating the thick protective layer, the metal tube or the electric wire may be damaged by the explosive pressure. Uses powdered or plastic explosives instead of the explosives described above to prevent imprinting of wire traces of the detonator on the metal surface. Preventing the electric wire from being damaged by colliding it with the electric wire through a metal tube (protection tube) and directly hitting the electric wire with the flight board, and metallurgically joining both the flight board and the protection tube to the electric wire. Thus, sufficient bonding strength is obtained. By these means, it is possible to obtain a metallurgical bond having a high bond strength with a small amount of explosive without scratching the electric wire.

(3) In order to prevent the electric wire from being largely deformed or broken by treating it with a strong explosive force such that the twisted wires in the inner layer of the electric wire are joined together, a thick rubber protective layer is used in (2). The protection tube that was considered to be used to eliminate it works effectively as it is.

(4) Instead of using a tapered metal tube, a flight board provided with a relative distance between a specific curved surface and an electric wire is installed so as to substantially cover the periphery of the electric wire, and the side of the flight board facing the electric wire. When exploding explosives that explode at a high speed covering the surface opposite to the explosives are blown by the explosive pressure of the explosives and collide with the electric wire, the moving speed at the collision point is the speed of sound of the metal that composes the electric wire and the flying board. Is 70% or less, and the metallurgical joining is achieved so that the flight speed of the flying plate in the direction perpendicular to the direction of explosion is sufficient to join the twisted wires of the inner layer. .

The configuration of the present invention will be described below with reference to the drawings.
FIG. 1 is a view showing a state in which respective elements for joining showing a typical embodiment of the present invention are combined, as seen from a plane perpendicular to a longitudinal axis of an electric wire. Thin protective material for protecting the surface of the flying board 3 and 4 are the flying board 3 and the protective tube 5.
A spacer for maintaining a proper distance between the protective tube 5 and the surface of the electric wire 7 and a spacer for maintaining a proper distance between the protective tube 5 and the electric wire 7. It means the installation position. Also, d is the vertical distance between the flying plate 3 and the protective tube 5 at the position farthest from the point a of the flying plate 3, L
Is the distance measured from the point a of the flight board 3 in the direction perpendicular to the longitudinal axis of the electric wire 7 and the distance b between the point b where the electric detonator 8 is installed and the flight board surface. ₀ indicates the length between corresponding positions on the surface of the electric wire 7. In FIG. 4, L and L ₀
Is indicated by a thick arrow.

Explosive 1 is 2 for metallurgically joining metals
When two metal plates are installed in parallel and explosive explosively explodes from one end to the other end and the metal plates collide with each other accordingly, the sonic velocity of longitudinal waves of these metals (hereinafter referred to as sonic velocity). ) Or less, and preferably explosive at an explosive velocity of 70% or less of the speed of sound of metal. But,
In the present invention, in order to satisfactorily bond all the components that form the joint, the flying plate 3 that flies by the explosion of the explosive 1
The protective plate 5 is installed so that the relative distance between the protective plate 5 and the protective tube 5 gradually increases as the explosion of the explosive 1 progresses.
By setting the traveling speed of the collision point between the protection tube 5 and the protection tube 5 to be 70% or less of the sound speed of the metal at the joint portion, the explosive speed of the explosive 1 is 70% or more of the sound speed of the metal. Good metallurgical bonding is also achieved with the explosives described in.

As is apparent from the figure, the distance d between the flight board 3 and the protective tube 5 measured perpendicularly from the flight board surface is set so as to increase with distance from the detonator. In the figure, the shape of the flight board 3 is drawn as an arc shape in which a part of a cylinder is cut out, but this is merely an example in practice, and other suitable ones can be provided as long as the requirements described later are satisfied. A shape, for example an elliptical cross section, is also acceptable. In the present invention, since the protective material 2 does not use a detonating wire as in the conventional method because powdery or plastic explosive is used in the present invention, there is no fear of leaving line marks, and therefore a thin coating film is applied by coating. Alternatively, a plastic or paper tape may be attached, and a maximum thickness of 1 mm or less is sufficient.

The spacer 4 is for maintaining an appropriate distance between the flying plate 3 and the protective tube 5, which will also be described later in detail together with the requirements for the explosive 1 and the flying plate 3. Since the protective tube 5 is subject to electrolytic corrosion if it is made of a material different from that of the electric wire 7, it must be made of the same material as the electric wire 7 together with the flying plate 3 and the spacer 4. That is, when the electric wire 7 is a copper wire, the flying plate 3, the spacer 4, and the protective tube 5 must be copper or a copper alloy, and when the electric wire 7 is an aluminum wire, it must be aluminum or an aluminum alloy. When the electric wire 7 is an ACSR (steel core aluminum stranded wire) electric wire in which the outer layer is an aluminum alloy and the inner layer (center layer) is steel, the flight board 3, the spacer 4 and the protective tube are selected according to the material of the outer layer. 5 must be aluminum or an aluminum alloy. Like the spacer 4, the spacer 6 is also for maintaining an appropriate distance between the electric wire 7 and the protective tube 5, and needs to be made of the same material as the electric wire 7. The electric detonator 8 is for detonating the explosive 1. However, the inner surface of the protective tube 5 and the surface of the electric wire 7 are installed so as to be parallel to each other.

FIG. 2 is a cross-sectional view of FIG. 1 viewed from a direction parallel to the plane of the drawing. Numbers with "'" correspond to the same numbered parts in FIG. L'is a distance measured on the longitudinal axis of the electric wire 7 at a position farthest from the electric detonator 8'of the flight board 3 '. In the figure, the electric detonator 8 is installed in the center of the flying board 3, but if the requirements described later are satisfied, the flying board 3 '
It may be installed at the edge of the or other suitable position.

Here, consider the situation when the explosive 1 is detonated by the electric detonator 8 in FIG. 1 and explodes from the point a to the portion hitting the corner of the flying plate. The length of explosive 1 or 1'from the point a in Fig. 1 or the corner of the flying plate a'in Fig. 2 is L "
Assuming that it is equal to the length of the corresponding position of the flight board 3 or 3 ′, L ″ = (L ² + L ′ ² ) ^1/2 ... 1). Furthermore, explosive 1 If the explosion speed of is D, explosive 1
Is detonated by the electric detonator 8 at point a, and then the explosion b
The time t ₁ required to reach the point is represented by t ₁ = L ″ / D 2 ...

Further, when the explosive 1 explodes, the flying plate 3 is ejected at a high speed to the opposite side of the explosive 1. The flying speed measured by the flying plate 3 in the direction perpendicular to the plane (hereinafter referred to as the flying speed) is v, and the time t ₂ from the point when the explosion reaches the point a until the point a collides with the surface of the protective tube. Is t ₂ = d / v ... 3). At the point a, the lower surface of the flying plate 3 is in contact with the surface of the protective tube 5, so if the time from the explosion to the contact is ignored, the point a collides with the protective tube 5 until the point b collides. Can be obtained by t ₃ = t ₁ + t ₂ = L ″ / D + d / v 4). What this expression means is that if the flight board 3 and the protection tube 5 are installed in parallel. If so, t ₃ = L ″ /
Since the flying plate 3 is installed so as to gradually separate from the point a to the point b, the time t ₃ required for the collision point of the flying plate 3 and the protective tube 5 to advance from a to b is d / v. It only means it will take longer. Further, the average speed V at which the collision at the point a progresses to the point b (hereinafter referred to as the moving speed of the rear collision point) V is: V = L ₀ / t ₃ = L ₀ / (L ″ / D + d / v) ... 5) is given.

Strictly speaking, when the flight board 3 is blown by the explosion of the explosive 1 in the direction opposite to the surface on which the explosive is installed, the direction is more forward than the direction perpendicular to the plane of the flight board 3 in the direction of the explosion. Although it is flown in a slightly tilted direction, when the moving speed V of the collision point is set sufficiently lower than the explosive speed D of the explosive, the error accompanying it is negligible. Also,
The object of the present invention is to make the flying board 3 move to 2 by the explosion of the explosive 1.
The two wires are joined via the flight board 3 by utilizing the phenomenon that the flight board 3 is strongly metallurgically joined to both wires by colliding at high speed with the center of the butted portion of the two wires. Therefore, the protective tube 5 plays a role of preventing the electric wire 7 from being significantly damaged or broken when the flying plate 3 collides with the electric wire 7 at a high speed at that time. It is joined to the electric wire 7 together with the plate 3 and serves as a joint.

Now, the moving speed V of the collision point and the collision speed v of the flying plate 3 to the protection tube 7 which are required to effectively join the electric wires 7 with the flying plate 3 and the protection tube 5 as joints will be described. With respect to the moving speed V of the collision point, good bonding cannot be expected when the moving speed V of the collision point exceeds 70% of the sound velocity of the metal theoretically and experimentally, but there has been no clear standard for the collision speed v. As a result of repeating many experiments and theoretical studies, the inventors reached the following conclusion. That is, the purpose of the present invention is to not only metallurgically bond the surfaces of the flying plate 3 and the protective tube 5 and the surface of the protective tube 5 and the electric wire 7, but also the inner layer portion of the electric wire 7 made of a stranded wire. As already mentioned, it is necessary to join even the twisted wires,
For that purpose, it is necessary to input into the electric wire 7 energy which is determined for each material type of the electric wire 7 and which is more than a certain amount per volume of the electric wire 7 as kinetic energy due to the flight of the flying plate 3. For example, in the case of the electric wire 7 made of a stranded aluminum wire, 400 M per volume of 1 m ³ including voids inside the electric wire 7
It turned out that it is necessary to input energy of j or more. In the case of a stranded copper wire, it is necessary to input energy of 900 Mj or more. It is considered that the reason why the material of the electric wire 7 is different between aluminum and copper is that copper has a higher deformation resistance and a higher melting point than aluminum, so that good bonding cannot be achieved unless more energy is applied.

The method of giving the required velocity v to the flying board 3 can be determined as follows. An appropriate amount of explosive is attached to the flying board 3 with reference to the embodiment of the present invention, and a process of exploding the explosive and causing the flying board 3 to fly toward the inside of the tube is photographed by flash X-rays, and the flying board is shot. There is a method of judging from the inclination angle of 3. Further, by arranging pins which are electrical contacts inside the flying board 3 at different distances and electrically shorting one after another in the process of deformation of the flying board 3, an electrical recording means such as an oscilloscope is used. A method of recording and judging from the distance-time relationship is also effective. Many of these methods are described in reference books, textbooks, and the like regarding the measurement of the explosion phenomenon, and those skilled in the art can easily implement them by referring to them.

As a means for determining an effective dose without utilizing these measuring means, each value is set with reference to the embodiment of the present invention, actual joining is performed, and the joined electric wire 7 is used.
There is a method of cutting and inspecting and inspecting conditions under which good bonding can be obtained by gradually increasing the amount of explosive if the inner layer of the electric wire 7 is not bonded. On the contrary, the wire 7 is broken,
When a large flaw occurs at the joint, the amount of explosive may be too large, so the dose should be gradually reduced to set an amount that can obtain an appropriate joint.

From the above description, the distance between the flight board 3 and the protection tube 5, or the shape of the flight board 3 which determines the distance, plays an important role in determining the moving speed V of the collision point. it is obvious. That is, to set the moving speed V of the collision point to 70% or less of the sonic velocity of the metal by accelerating the flying plate 3 with the explosive having an explosion velocity of 70% or more of the sonic velocity of the metal to collide with the protective tube 5, Specifically, it is necessary to gradually increase as the vertical distance between the flying plate 3 and the protective tube 5 in FIG. 1 moves from the point a to the point b. The explosive velocity D of the explosive 1, the distance L ″ between the flying plates 3 at points a and b, the corresponding distance L ⁰ of the electric wire 7, the vertical distance d between the flying plate 3 and the protective tube 5 at point b, and the flying plate. If the vertical flight speed v of 3 is known, the moving speed V of the collision point can be easily obtained from the above relational expression.

Here, it is assumed that L ″ is 70 mm and L ₀ is 60 m.
m, the explosive velocity D of the explosive 1 is 7,000 m / sec, the vertical distance d between the flying plate 3 and the protective tube 5 at point b is 12 mm, the flying plate 3
If the flight speed of the vehicle is 1,200 m / sec, then t ₁ = L ″ / D = 70 mm / 7 mm / microsecond = 10 microseconds t ₂ = d / v = 12 mm / 1.2 mm / microsecond = 10 microseconds t ₃ = t ₁ + t ₂ = 20 microseconds V = L ₀ / t ₃ = 60 mm / 20 microseconds = 3 mm / microseconds, and the moving speed V of the collision point is 3 mm / microseconds = 3,0
At 00 m / sec, it is 70% or less of the sound velocity of most metals, and in particular, 4,494 m / sec, which is 70% of the sound velocity of 6,420 m / sec of aluminum, which is often used for electric wires.
70% of the sound velocity of copper, 5,010 m / sec, 3,507 m /
Clearly well below the second. However, this calculation is to obtain the moving speed V of the collision point from the point a of the flying plate 3 to the position b farthest from the point a. For example, the end of the flying plate 3 in the direction parallel to the paper surface of FIG. 1 from the point a. The moving speed of the collision point up to is slower. Considering this as an application of the above description, the calculation is easy, and the description thereof is omitted.

Next, the thicknesses of the flying board 3 and the protective tube 5 are determined in consideration of the following factors. After the joining is performed, the flying plate 3 and the protective tube 5 take charge of the mechanical strength of the electric wire at the joining portion and also serve as an electric path when a current flows from one electric wire to the other electric wire. First, in order to guarantee the mechanical strength of the electric wire, the following requirements must be met. All electric wires are specified by standards, and a certain level of breaking strength must be guaranteed for each type. If the strength to be guaranteed is F,
Assuming that the flying plate 3 has a cross-sectional area of Sf, the protective tube 5 has a cross-sectional area of Su, and the flying plate 3 and the protective tube 5 are made of the same material, and the breaking strength per unit cross-sectional area thereof is f, f (Sf + Su)> F.・ ・ ・ ・ ・ ・ ・ ・ Sf and Su may be set so as to satisfy 6). Regarding how to distribute the cross-sectional area or the thickness of the flying plate 3 and the protective tube 5, the thickness of the flying plate 3 is involved in determining the flying speed and consequently the energy input for joining. From the above, if the flying speed of the flying plate 3 is known, how much energy is input to the joint can be obtained by the following equation. ^{E = mVp 2/2 ·········· 7} ) where, E is the kinetic energy of the flying plate 3, m is the mass of the flying plate 3. If this E reaches the energy required for the above-mentioned joining, the requirement for joining is satisfied.

Unlike the thickness of the flying plate 3 related to the input energy E, the thickness of the flying tube 3 is different from that of the flying plate 3.
When it collides with the electric wire 7
It must be thick enough to prevent scratches and breakage, and must be determined empirically. However, it is possible to avoid setting the thickness of the protective tube 5 to be 50% or more thicker than the thickness of the flying plate. However, this can also be easily determined by those skilled in the art with reference to the present specification. The distance between the protective tube 5 and the electric wire 7, or the spacer 6 that determines the distance
It is not necessary to define the dimensions of s as strictly as in the case of the spacer 4. The reason is that the flying plate 3 collides with the protective tube 5 and the vertical velocity at which the protective tube 5 is blown toward the electric wire 7 is such that the thickness of the protective tube 5 is equal to or less than the thickness of the flying plate 3. If
It may be considered to be almost equal to v at a speed slightly lower than the vertical velocity v of the flying board 3, and if the requirement of the required input energy mentioned above is achieved, it will be a problem. Because not. Generally, the distance between the protective tube 5 and the electric wire 7, or the dimension of the spacer 6 which determines the distance, may be set between 0.1 mm and 1 mm, but may be shorter or longer if necessary. .

As a matter of course, it is appropriate that the electric wires 7 have their joint ends butted against each other at the center of the flying plate 3. However, the electric conductors 7 can be appropriately displaced depending on the joint requirements, which is also designed by the designer. You can think of it as the discretionary range of. Further, the length of the flying board 3 is joined to the electric wire 7 through the protective tube 5 over the entire length as a requirement for achieving good electrical connection, and the electric wire 7 is butted at the center of the flying board 3. Considering that, when the radius of the electric wire 7 is r and the flight board 3 is joined so as to cover almost the circumference of the electric wire, the length is taken as C, and πrC ≧ πr ² ... ) Is required. This means that the joint surface area on one side of the electric wire 7 must be equal to or larger than the cross-sectional area of the electric wire 7. However, in the case of an aluminum electric wire in which a steel wire for reinforcement is arranged at the center, the right side may be directed to the effective area as a conductor.
In addition, in the equation 8), the cross-sectional area is calculated assuming that the electric wire is not a stranded wire but an integral wire. However, if the effective cross-sectional area of the stranded wire is known, enter that value in the right side. Good. Also,
If the flight board 3 and the protection tube 5 have the same cross-sectional area, the electric wire 7
It is assumed that it is equal to or larger than the effective area of.

For example, an electric wire made of a stranded aluminum wire, which is called an ACSR160, is formed by twisting 30 aluminum wires having an outer diameter of 18.2 mm and a diameter of 2.6 mm around 7 steel wires having a diameter of 2.6 mm. The effective cross-sectional area of the electric wire is 159.3 mm2 ^, and by substituting this into the right side, the required length L of the flight board 3 is calculated to be 5.6 mm. Actually, it is not possible to accelerate the flying plate 3 having a length of less than 6 mm at high speed with explosives and join it to the electric wire 7 through the protective tube 5, so that the flying plate 3 having a total length of 40 mm or more, for example, can be used.
From the above, it can be seen from the above that if the flight board 3 having a practically connectable length is used, the electrical connection requirement can be achieved at any length.

FIG. 3 is a sectional view parallel to the longitudinal axis of the electric wire, showing another example of the embodiment of the present invention, and the numbers with "" correspond to the respective numbers in FIG. In FIG. 1, the flying plate 3 is formed by cutting a part of a cylindrical metal along the axis of the cylinder, and is installed so as to be eccentric with respect to the cross-sectional center of the electric wire 7. Although the gradual distance change necessary for the pipe was obtained, in this figure, a part of the tapered pipe was cut out, and the initiation point was installed at the end of the flight plate bent into a tapered pipe on the small curvature side. ing.

A further characteristic is that the center of the electric wire 7 "is properly eccentrically arranged with respect to the center of the arc of the arc-shaped cross section so that the average moving speed V of the collision points is substantially equal at all positions. There are things you can do, for example:
In the example of FIG. 1, for the components that explode from the electric detonator 8 at a right angle to the paper surface, the average moving speed V at the point where the flying plate 3 collides with the protective tube 5 is equal to the explosive explosive speed D. Therefore, immediately below that part, the flight board 3, the protection tube 5, and the protection tube 5
However, good metallurgical bonding between the wires 7 and the stranded wires in the inner layer portion of the wire 7 cannot be expected, but good metallurgical bonding can be expected in most parts in the arrangement of FIG. 3 and the shape of the flying plate 3. That is, the shape of the flying board 3 "and its electric wire 7" are set so that the average moving speeds V of the collision points from the a "point to the b" point, the a "point to the c" point, and the a "point to the d" point are made equal. The amount of eccentricity from can be calculated using equations 1) to 5).

There are the following two reasons why the method shown in FIG. 1 and the method shown in FIG. 1) When a layer of explosive is pasted around a closed cylinder or a tapered tube and a detonation is initiated from a single point, the explosion advances radially on the surface of the explosive and collides at a position opposite to the detonated point. Since the explosion pressure doubles at the point of collision, the flying plate 3 is damaged at that part, and the flying speed partially increases, so that the protective tube 5 at the part where the part collides
Or the electric wire 7 is damaged, or receives a large strain. The problem can be completely solved by forming an open tube or an open tapered tube as in the present invention. 2) It is easy to make a curved surface from a flat plate, but it is very difficult and costly to make a closed tube, especially in the case of a tapered tube. Although a shape obtained by cutting out a part of a cylinder can give an arbitrary curvature, it is similarly expensive to make a cylinder having an arbitrary thickness and diameter. Existing standard-shaped cylinders cannot always be used as they are.

[0030]

The present invention is applicable to mechanical compression, caulking, etc., when joining an electric wire, which is a stranded wire of aluminum or its alloy, copper or a copper alloy, such as a power transmission line and a distribution line, by utilizing explosive pressure. Irrespective of the effect, not only the part that appears on the surface of the stranded wire,
By metallurgically bonding up to the inner layer part, compared with the conventional method of simply bonding by mechanical compression or caulking, it is possible to achieve reliable bonding with less bonding and length, and therefore with less explosive usage. A method is provided in which there is no gap between the metal pipe and the electric wire or the twisted wire of the electric wire, and rainwater or corrosive gas does not enter the space and is easily corroded.

Further, in the case of covering a rod-shaped object such as a conventional electric wire and metallurgically joining the metal plates by the explosion of explosives, the metal plate or the metal tube is installed in parallel with the electric wire and is opposite to the surface facing the electric wire. An explosive that explodes at an explosive velocity lower than the sonic velocity of the metal (hereinafter referred to as low-speed explosive) is installed on the side surface to explode from one end, and a metal plate or metal tube is progressively collided with the electric wire to join or When using explosives that explode at an explosive velocity higher than the sound velocity of
A so-called tapered or trumpet-shaped metal tube with one end thin and the other end thick is located around the electric wire, and explosives installed outside the tube are detonated from the thin side of the tube, causing the tube to collide with the electric wire. Although there was no choice but to join so that the traveling speed was lower than the explosive speed of the explosive, the present invention allows the electric wires to be easily joined by the explosive without using a specially shaped metal tube. It became so. The fact that high-speed explosives can be used for joining means that high-speed explosives have a higher explosion pressure than low-speed explosives. It provides an advantageous method in all respects in implementing the joining of electric wires due to the explosion of explosives, such as reduction and facilitation of protective measures.

[0032]

Example 1 The present invention will be described below with reference to examples. As the flying plate 3 of FIG. 1, a 60 mm long, 100 mm wide, 3 mm thick industrial pure aluminum plate is prepared, and the radius of curvature at the outer circumference is 20 mm, and the length is 60 mm and the diameter is 36 m.
A part of a cylinder of m was cut into a shape with a width of about 13 mm cut along the axis, and a vinyl chloride-based paint was further spray-painted on the curved surface on the outer side to obtain a protective material 2. Also, as the protective tube 5, an outer diameter of 22 mm, an inner diameter of 19 mm, and a length of 12
A 0 mm industrial pure aluminum tube was prepared. The electric wire 7 is a transmission line called ACSR160, and has a length of 300 mm, which is obtained by twisting 30 aluminum wires having an outer diameter of 18.2 mm and a diameter of 2.6 mm around 7 steel wires having a diameter of 2.6 mm. Two pieces were prepared, inserted from both ends of the protective tube 5, and abutted at the center. At that time, as the spacer 6, an aluminum wire having a diameter of 0.3 mm is wound once at a position of 5 mm and a position of 55 mm from the end of the electric wire 7 on the side where the electric wire 7 is inserted into the protective tube 5, and the electric wire 7 is approximately at the center of the protective tube 5. I was positioned. A composition C4 explosive having a thickness of 3 mm was placed as the explosive 1 so as to cover the entire outer circumference of the flying board 3. As a result, the amount of explosive 1 was 33 g and the density was 1.65 g / cm ^3.
Met. The flying plate 3 with the explosive 1 attached is arranged such that the center of the longitudinal axis thereof coincides with the center of the longitudinal axis of the protective tube 5,
In addition, the apex position of the arc is in contact with the protective tube 5, and both ends of the arc are equal to 7.5 mm from the protective tube 5, respectively. Intervening between the protective tube 5 and
The surface of the explosive 1 and the portion of the protective tube 5 protruding from the flying plate 3 were fixed with a vinyl chloride adhesive tape, and the electric detonator 8 was fixed to the central portion of the explosive 1 with a vinyl chloride adhesive tape.

The combination thus obtained is placed on sand with a thickness of about 300 mm and a diameter of about 2,000 mm, and the electric detonator 8 is energized from a remote position with a parallel electric wire coated with vinyl chloride. And detonated explosive 1. As a result, explosive 1 exploded at an explosion speed of 7,100 m / sec.
This explosion speed corresponds to about 110% of the sound speed 6,420 m / sec of aluminum, which is a metal forming the flying plate 3, the protective tube 5, and the electric wire 7. Due to the explosion of the explosive 1, the flying plate 3 collided with the protective tube 5 at high speed, and was joined to the electric wire 7 while being joined to the protective tube 5. The joined body collected after the explosion was cut parallel to the axis around the longitudinal axis of the electric wire 7 and the joint surface was inspected with an optical microscope. As a result, the flying plate 3 and the protective tube 5, the protective tube 5 and the electric wire 7 were separated. Both the surface and the twisted wires in the inner layer portion of the electric wire 7 were metallurgically bonded at the corrugated boundary. However, immediately below the part where the flying board 3 was in contact with the protective tube 5,
Flying plate 3, protective tube 5, protective tube 5 over a width of about 7 mm
Although the surface of the electric wire 7 and the surface of the electric wire 7 are mechanically contacted with each other, it is recognized that they are not metallurgically joined. However, in the portion which further corresponds to the inner layer of the electric wire 7, the twisted wires of the electric wire 7 are It was confirmed that they were metallurgically bonded. The flying plate 3 was joined to the entire surface of the protective tube 5 leaving a groove-shaped portion having a width of about 0.5 mm to 1 mm and the length of the flying plate 3.

Another joined body produced in the same manner as above was subjected to a tensile strength test by a tensile tester, and the electric wire 7
Is 7,110 kgf above the specified strength except for the joint
However, no fracture was observed at the joint and it was confirmed that the joint was achieved with sufficient strength. In order to find out how much energy was input at the time of joining, prepare the one for which the spacer 4, the protective tube 5, the spacer 6 and the electric wire 7 were removed from the combination for joining, and inside the flying board 3,
In order to measure the flight speed of the flight board 3, six pins that are electrical contact points are installed at different distances from the inner surface of the flight board 3, and the explosive 1 is exploded to place the pins at each position. The contact time was recorded on an oscilloscope. As a result, flying board 3
The average flying speed of the flying plate at a position of 1 mm to 8 mm from the inner surface of the was 1,180 m / sec. From the obtained flight speed, the amount of explosive 1 and the mass of the flying plate 3, when the energy input to the joint is calculated by the equation 7), it is found that 2,160 Mj / m ³ is input per unit volume of the electric wire. I understood.

From the measured flight speed of the flight board 3 and the explosive speed of the explosive 1, the moving speed of the collision point between the flight board 3 and the protective tube 5 in the direction from the mounting position of the electric detonator 8 to the corner of the flight board is calculated. As a result, it was found that at 2,830 m / sec, it was sufficiently lower than 4,494 m / sec, which is 70% of the sound velocity of aluminum.

[0036]

Comparative Example 1 The same experiment as in Example 1 was conducted. However,
Other conditions were the same, and as the flying plate 3, an industrial pure aluminum tube having an outer diameter of 36 mm, an inner diameter of 30 mm and a length of 60 mm was prepared, and a composition C4 having a thickness of 3 mm was mounted as the explosive 1 on the entire outer circumference thereof. When the flight board 3 was attached to the protection tube and the electric detonator 8 attached at the same position was energized to explode the explosive 1 in the same manner as in Example 1, the electric detonator 8
The flying plate 3 broke at a position opposite to the position where the mounting plate was mounted and collided with the protection tube 5, and as a result, the electric wire was broken at the position where the flying plate 3 collided and was separated, and, of course, joining was not possible.

[0037]

Comparative Example 2 The same experiment as in Example 1 was conducted. Example 1
The difference is that the flight board 3 is installed at the same relative position as the first embodiment with respect to the flight board 3 without the protection tube 5 and the spacer 6, and the flight board 3 is similar to the first embodiment. Explosive 1 was detonated. As a result, the flight board 3 collided with the electric wire 7, and the flight board 3 and the electric wire 7 were firmly metallurgically joined together including the twisted wires in the inner layer of the electric wire 7, but from the end of the flight board 3 of the electric wire 7. At the protruding portion, the aluminum stranded wire was completely cut, leaving the core of the steel wire. It is considered that this is because the aluminum wire was cut by the shearing stress generated at the end of the flying plate 3 because there was no protective tube 5.

Considering together with the results of Comparative Example 1, when the flying plate 3 is tubular, the explosions progressing from both sides when the explosive 1 explodes collides on the side opposite to the installation position of the electric detonator 8, Since the pressure at that portion becomes extremely high, the flying board 3 is broken and good joining cannot be performed. Further, in the case where the protective tube 5 is not provided, if the attempt is made to join the twisted wires in the inner layer of the electric wire 7, the flying board 3 will not be joined. It is clear that the electric wire 7 protruding from both ends of the is cut by the shear stress.

[0039]

[Embodiment 2] The flying plate 3 of FIG. 3 has a width of 72 mm at one end.
Prepare a copper plate with the other end having a width of 110 mm, a length of 60 mm and a thickness of 3 mm, and the end having a width of 72 mm has an inner radius of 11.5 m.
The m and the width of 110 mm were bent into an arc shape having an inner radius of 18 mm. As a result, a copper plate having a thickness of 2 mm had a shape in which a part of a tapered tube whose one end was substantially closed and whose other end was opened by a width of about 15 mm was cut into a triangle along the axis of the tube. The outer surface of the flying body 3 was spray-coated with a layer of vinyl chloride-based paint as the protective material 2. A composition C4 explosive having a thickness of 3 mm and a weight of 30 g was installed as the explosive 1 on the protective material 2 so as to cover the entire outer circumference of the flying plate 3.

As the electric wires 7 to be joined, 37 pieces of hard copper power transmission wires having an outer diameter of 18.2 mm and φ2.6 mm of 37 hard copper wires having a length of 300 mm are twisted to each other. A copper tube having a diameter of 23 mm, an inner diameter of 19 mm and a length of 120 mm was inserted as the protective tube 5 from both ends thereof, and was abutted at the center. At that time, the spacer 6 has a diameter of 0.3 mm.
5mm from the end where the copper wire of is inserted into the protective tube 5 of the electric wire 7.
The wire 7 was wound once at the position of and the position of 55 mm so that the electric wire 7 was positioned substantially at the center of the protective tube 5. Both ends of the protection tube 5 and the portion of the electric wire 7 protruding from the protection tube 5 are fixed with an adhesive tape of vinyl chloride, and the flight board 3 on which the explosive 1 and the like are mounted is centered in the length direction of the protection tube 5. The arc having the smaller radius of the flying plate 3 is in contact with the protective tube 5 so as to coincide with the center in the vertical direction, and the larger radius has the notch at both ends of the notch from the protective tube 5. The vertical distance is about 7 mm, the part on the opposite side of the notch is about 6 mm from the protective tube 5, and an aluminum plate having a thickness of 0.1 mm is interposed as a spacer 4, and a vinyl chloride adhesive tape is used. Fixed in.

The thus-combined product is placed on sand with a thickness of about 300 mm and a diameter of about 2,000 mm, and an electric detonator 8 is attached to the explosive 1 at the center of the arcuate end of the small shape. It was fixed with an adhesive tape made of paper, and the electric detonator 8 was energized from a remote position with a parallel electric wire coated with vinyl chloride to detonate the explosive 1. As a result, explosive 1 is 7,100 m
It exploded at an explosive speed of / sec.

Due to the explosion of the explosive 1, the flying plate 3 collided with the protective tube 5 at high speed, and was joined to the electric wire 7 while being joined to the protective tube 5. The joined body recovered after the explosion was cut parallel to the axis with the longitudinal axis of the electric wire 7 as the center, and the joint surface was inspected with an optical microscope. As a result, the flying plate 3, the protective tube 5, the protective tube 5, and the electric wire 7 were observed. The surface of the wire and the stranded wires in the inner layer of the wire 7 were metallurgically bonded at the boundary of the corrugation.

A tensile strength test was conducted on the other bonded body produced in the same manner as described above using a tensile tester.
Is 7,890 kgf above the specified strength except for the joint
However, no fracture was observed at the joint and it was confirmed that the joint was achieved with sufficient strength.

In order to find out how much energy was applied at the time of joining, a combination obtained by removing the spacer 5, the protection tube 5, the spacer 6 and the electric wire 7 from the combination for joining was prepared and placed inside the flying plate 3. , 6 pins which are electrical contact points for measuring the flight speed of the flying board 3, the flying board 3
It was installed by changing the distance from the inner surface of explosive, explosive 1 was exploded, and the contact time at each position of the pin was recorded on the oscilloscope. As a result, the average velocity of the flight tubes within the range of 1 mm to 8 mm from the inner surface of the flight plate 3 where the flight plates 3 and the protection tubes 5 collide was 465 m / sec. From the obtained flight speed, the amount of explosive 1 and the mass of the flying plate 3, the energy input to the joint was calculated by the equation 3), and it was found that 977 Mj / m ³ was input per unit volume of the electric wire. It was. This value exceeds 900 Mj / m ³ , which is the minimum value required for joining a stranded copper wire.

[0045]

Comparative Example 3 The experiment of Example 2 was repeated. However, the thickness of explosive 1 was changed to 2 mm. As a result, the weight of the explosive 1 was 20 g. As a result of detonating explosive 1, it exploded at an explosion speed of 6,980 m / sec. When the cross section of the recovered bonded body was inspected in the same manner as in Example 1, the flying plate 3 and the protective tube 5 showed good metallurgical bonding, and the protective tube 5 and the electric wire 7 were shown.
The surface of the wire was partially metallurgically bonded, but the stranded wires in the inner layer of the wire 7 were not bonded.

When the flight speed of the flight board 3 was measured in the same manner as in Example 1, the speed at the position where the flight board 3 and the protective tube 5 collide was 320 m / sec, and the unit volume of the electric wire 7 was calculated from the equation 3). It was found that 462 Mj / m ³ was input per hit. This value is less than the energy required to be applied per unit volume of the copper stranded wire, 900 Mj / m ³ , and it has been found that a larger amount of energy needs to be applied to obtain good bonding.

[0047]

Comparative Example 4 The experiment of Example 2 was repeated. However, the protective tube 5 was removed, and the flying plate 3 and the electric wire 7 were fixed so that the relative positions thereof were the same as in Example 2. When the explosive 1 was exploded, the flight board 3 and the electric wire 7 were joined, but the part of the electric wire 7 that protruded from the end of the flight board 3 was stripped at each end of the flight board, except for 5 to 7 stranded wires, It was broken by the shearing stress caused by the collision of the flying board 3.

When the joint portion was cut parallel to the longitudinal axis of the electric wire and inspected with an optical microscope, the flying plate 3 and the surface of the electric wire 7 and the twisted wires in the inner layer of the electric wire 7 were metallurgically bonded. It was In this experiment, the conditions for obtaining a good joint were satisfied, but since the protective tube 5 was lacking, the electric wire 7 was broken by the shear stress at both ends of the flying plate 3, and the existence of the protective tube 5 was favorable together with the input energy amount. Show that it is an important requirement for achieving bonding.

[0049]

According to the present invention, in the case of joining electric wires using a metal pipe as a joint under explosive pressure, a protective material such as thick rubber is used to prevent damage to the metal pipe or electric wire due to explosive pressure. Since it covered the pipe and the electric wire, it was necessary to use a large amount of explosive, and between the metal pipe and the electric wire, the stranded wire of the inner layer of the electric wire was simply joined by mechanical compression or caulking, By removing the extremely thick protective material, incorporating a metal protective tube to protect the electric wire, and constructing with appropriate input energy, a metal plate that is accelerated by explosive pressure and flies at high speed consists of stranded wire In the method of joining by colliding with the electric wire, even the stranded wires in the inner layer of the electric wire are metallurgically joined, and rainwater or corrosive gas enters the void of the stranded wire joint to corrode the electric wire. Prevent and prevent metal pipe at both ends of metal pipe It is an industrially effective invention that effectively prevents the electric wire from breaking due to shear stress when the electric wire collides with the electric wire and easily obtains a good joint.

Further, as compared with the explosive type electric wire joint which has been often used for electric wire connection, the amount of explosive is reduced and the auxiliary devices such as a protective tube are also reduced, which enables a compact design as a whole. . Further, since this type of joint has a very large noise level at the time of explosion, it was mainly used for power transmission lines in mountainous areas far from the house. Even if it is installed, a compact soundproofing device is enough, and it is possible to clear environmental problems during construction even with transmission and distribution lines near urban areas that could not be applied until now. It is now possible to provide a wire connection device. Although the description of the present invention has described the method of joining two electric wires by butting, that is, the method of joining such as a linear sleeve, the present invention is not limited to this and is also applicable to one continuous electric wire. Of course. Those skilled in the art can easily think that it can be used as a repair sleeve used when the wire of the electric wire is damaged or cut.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing how to combine members of an example for carrying out the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG. 1, showing one example of the present invention.

FIG. 3 is a diagram showing another example of the embodiment of the present invention.

FIG. 4 is a diagram showing L and L ₀ .

[Explanation of symbols]

 1, 1 ', 1 "explosive 2, 2', 2" protective material 3, 3 ', 3 "flight board 4, 4', 4" spacer between flight board and protection tube 5, 5 ', 5 "protection Tube 6, 6 ', 6 "Spacer between protective tube and electric wire 7, 7', 7" Electric wire 8, 8 ', 8 "Detonator

Front page continuation (72) Inventor Eiji Nishida 1-8-1, Hisamoto, Takatsu-ku, Kawasaki-shi, Kanagawa Asahi Electric Co., Ltd.

Claims (1)

[Claims] 1. An outer circumference of an electric wire to be joined is covered with a protective body made of a metal of the same type as that of the outer layer of the electric wire and formed in advance into a tubular curved surface, and the outer side of the metallic body is made of the same material as the protective body. A method of arranging a flying board that consists of and that flies by the explosive pressure of explosive that explodes at a speed of 70% or more of the speed of sound of the metal and collides with the protective body, and metallurgically join the flying board, the protective body, and the electric wire together The explosive is installed outside the curved surface of the flight plate, and the explosive is progressively exploded from one end to the other, and the explosive charges the traveling speed of the collision point between the flight plate and the protector to join. 70% of the sound velocity of the outer metal
The following is a method of joining electric wires, characterized in that the flight speed of the flight tube in a direction perpendicular to the direction of explosion is sufficient to join the twisted wires in the inner layer.