JPH08161937A - Instrumentation wire cable - Google Patents

Abstract

PURPOSE: To provide an instrumentation wire cable which is excellent in bending fatigue resistance and tensile strength, has a simple construction, and can be manufactured at a low cost. CONSTITUTION: A large number of element wires 2, which are plated with excellently conductive material and are made of steel, are bundled in parallel so as to form a strand 4. The strands 4 are covered by an insulator 5 so as to form a conductor cable 6. Seven of such conductor cables 6 are stranded so as to be contained in a sheath 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an instrumentation electric wire cable used for transmission of control signals and the like.

[0002]

2. Description of the Related Art Generally, an electric wire cable of this type has a large number of conductors housed in a sheath. As a conductor, in order to reduce the bending stress, a wire as thin as possible is used, and the wire is braided on the outer periphery of the core material. As the core material, a synthetic fiber having high tensile strength is used in order to obtain high tensile strength.

[0003]

However, such a conventional electric wire cable has a problem that the structure is complicated and the cost is high. Therefore, an object of the present invention is to provide an electric wire cable for instrumentation, which has excellent bending fatigue resistance and tensile strength, and has a simple structure and can be manufactured at low cost.

[0004]

[Means for Solving the Problems] That is, in the present invention, a large number of steel wires plated with good electrical conductivity are bundled in parallel to form a strand, and the strand is covered with an insulator to form a conductor line. , Twist this conductor cord and store it in a sheath, or bundle a number of steel wires plated with good electrical conductivity in parallel and add a moderate pitch of twist to the whole. A strand is formed by covering the strand with an insulator to form a conductor line, and a plurality of such conductor lines are twisted and housed in a sheath to form an electric wire cable for instrumentation.

And, preferably, any one of brass, bronze, copper, zinc, aluminum, or aluminum-zinc alloy is used as a material for plating applied to the wires.

[0006]

In the electric wire cable having such a structure, since the plated steel wire is used as the conductor, it is excellent in bending fatigue resistance and tensile strength, and has a simple structure and can be manufactured at low cost. It becomes possible to do.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. The first embodiment of the present invention will be described. First, in the present invention, a wire made of steel (carbon steel) plated with good conductivity such as brass, bronze, copper or zinc is used as the conductor. FIG. 1 shows a cross section of the conductor 1, in which 2 is an element wire and 3 is a plating layer. The diameter of the wire 2 is 0.1 to 0.3 mm, preferably 0.15 mm.

A large number of such conductors 1 are bundled in parallel as shown in FIGS. 2 and 3 to form a strand 4, and the strand 4 is covered with an insulator 5 such as rubber to form a conductor rope 6. Then, as shown in FIG. 4, seven such conductor wires 6 are twisted into a so-called 1 × 7 structure, that is, a structure in which six conductor wires 6 are arranged on the outer circumference of one core conductor wire 6. Then, the twisted conductor cords 6 are housed in a sheath 7 made of rubber or plastic to form an electric cable 8.

In the electric wire cable 8 having such a structure, as the conductor 1, a plated steel wire 2 is used.
Since it is used, it has excellent bending fatigue resistance and tensile strength, and since it does not require braiding of strands and interposition of core material like conventional electric cables, it has a simple structure and can be manufactured at low cost. You can

FIGS. 5 to 7 show a second embodiment of the present invention. In the first embodiment, a large number of conductors 1 are bundled in parallel to form a strand 4, but in the case of the second embodiment, a large number of conductors 1 are bundled in parallel and the whole is The strand 4 is formed by adding a twist having a gentle pitch.

The twisted strands 4 are covered with an insulator 5 such as rubber to form conductor lines 6, and seven such conductor lines 6 are formed into a 1 × 7 structure as shown in FIG. An electric wire cable 8 is constructed by twisting and then accommodating the twisted conductor cable 6 in a sheath 7 made of rubber or plastic. In this case, the pitch multiple P of the twist of the conductor 1 is set to P = rφ / d or more. However, r: bending radius φ: bending angle π / 2 or more d: outer diameter of the strand 4.

In the present invention, a plated steel wire is used as the conductor, but it is conceivable to use a copper wire as the conductor. In Table 1 below,
The physical properties of copper wire (Cu) and steel wire (carbon steel) are shown in comparison.

[0013]

[Table 1]

As shown in this table, the permissible bending strain is 1/433 in the case of a copper wire, and 1/105 in the case of a steel wire, and therefore the steel wire as a conductor is In the electric wire cable of the present invention using, the fatigue resistance is four times or more as compared with the case of using a copper wire, and fatigue disconnection is reliably prevented. Further, there is an advantage that the local bending radius can be reduced to 1/4 or less as compared with the case of the copper wire, and the wiring space can be narrowed.

Further, the tensile strength is 6 times or more as compared with the case of the copper wire, which is strong against the tensile load and the reliability is remarkably improved. Further, the steel wire is cheaper and more cost effective than the copper wire.

When a large number of conductors are bundled in parallel to form a strand as in the first embodiment of the present invention, the conductors are in line contact with each other and are on the same plane as the bending. Since the conductors are in the plane, the sliding between the conductors becomes smooth, and as a result, the stress level becomes smaller than that in the case where the strand has a twisted structure as in the second embodiment.

The safety factor SF = (σY / E) / (d / 2r) is the same when the conductors have the same diameter and the strands have a twisted structure. It is four times larger, but it becomes larger by bundling the conductors as steel wires in parallel to form strands.

When a large number of conductors are twisted to form a strand as in the second embodiment, the pitch is
Since the bending length is equal to or greater than the bending angle φ = π / 2 (90 degrees), the sliding between conductors is also smooth, and as a result, the stress level can be kept low even with twisted strands. it can.

When the electric wire cable is used for control signals, when the conductors have the same cross-sectional area (for example, 3.5 mm ² ),
The electric resistance of steel wire is 8.2 times that of copper wire, but if the total length of the cable that is repeatedly moved repeatedly is about 5 m, the total resistance of the cable alone is 0.14 / 3.5 mm ² × 5 m = 0.2 Ω. Become. If the insertion resistance of the circuit is about 1 KΩ, the voltage drop of the cable will be +5 to 15V x 0.2 / (1000 + 0.2) = 0.001 to 0.003V when the drive power source is +5 to 15V, which is small. Even if the cross-sectional area is 0.24 mm ² , the resistance is 3 Ω and the voltage drop is 0.015 to 0.045 V.
It does not affect ON-OFF operation.

[0020]

As described above, according to the present invention, it is possible to provide an electric wire cable for instrumentation which is excellent in bending fatigue resistance and tensile strength, has a simple structure, and can be manufactured at low cost. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a conductor of an electric cable according to a first embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of the strand of the electric wire cable according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view of the strand of the electric wire cable according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view of the electric wire cable according to the first embodiment of the present invention.

FIG. 5 is a vertical cross-sectional view of a strand of an electric wire cable according to a second embodiment of the present invention.

FIG. 6 is a cross-sectional view of a strand of an electric cable according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view of an electric wire cable according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conductor 2 ... Elemental wire 3 ... Plating layer 4 ... Strand 5 ... Insulator 6 ... Conductor rope 7 ... Sheath 8 ... Electric wire cable

Claims (3)

[Claims] Claims: 1. A large number of steel strands plated with good electrical conductivity are bundled in parallel to form a strand, and the strand is covered with an insulator to form a conductor line, and a plurality of the conductor lines are twisted together. Instrumentation electric cable that is stored in the sheath. 2. A large number of steel wires plated with good electrical conductivity are bundled in parallel and twisted at a moderate pitch to form a strand, and the strand is covered with an insulator to form a conductor. A cable for instrumentation, which is formed by twisting a plurality of such conductors and storing them in a sheath. 3. The instrumentation according to claim 1 or 2, wherein the material of the plating applied to the strand is any one of brass, bronze, copper, zinc, aluminum and aluminum-zinc alloy. Electric wire cable.