JPH09282952A - Rubber / plastic covered electric wire, its manufacturing method and its manufacturing apparatus - Google Patents

Abstract

(57) [PROBLEMS] To provide a rubber / plastic covered electric wire which is not easily damaged by an identifier and does not have to be formed in a separate step, and which has excellent electrical characteristics, a manufacturing method thereof, and a manufacturing apparatus thereof. It is provided. In a rubber / plastic covered electric wire in which a conductor / 2 is extruded around a rubber / plastic layer, the rubber / plastic layer forms a protrusion 3 that forms an identification body.
Rubber / plastic inner layer 3 having a and its protrusion 3
and a rubber / plastic outer layer 4 covering the periphery of the rubber / plastic inner layer 3 so as to expose at least a part of a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber / plastic coated electric wire, a method for manufacturing the same, and a manufacturing apparatus for the same, and in particular, a rubber having a color band for easy identification.
The present invention relates to a plastic-coated electric wire, a manufacturing method thereof, and a manufacturing apparatus thereof.

[0002]

2. Description of the Related Art Generally, as a rubber / plastic covered electric wire having a colored band for easy identification at the time of connection work, a rubber / plastic which is an insulator has a color different from that of the rubber / plastic. Ink printed in a linear or spiral shape, or as shown in FIG. 11, in the rubber / plastic covered electric wire 31 in which the periphery of the core wire (conductor) 32 is covered with the rubber / plastic layer 34, the rubber / plastic layer 34 In the surface layer portion of (1), an identification body 33 made of a rubber / plastic material having a color different from that of the rubber / plastic layer 34 is embedded.

[0003]

However, the conventional rubber / plastic covered electric wire having a color band has the following problems.

The rubber / plastic coated electric wire in which the former ink is linearly or spirally printed has to be printed in a separate step after the core (conductor) is covered with an insulator (rubber / plastic). However, there is a problem that the number of manufacturing processes increases, and accordingly, it takes a long time to manufacture the rubber / plastic-coated electric wire and the manufacturing cost increases. Further, in the twisting step, which is the next step of printing, there is a problem that the printing ink is easily peeled off, as the printing is peeled off due to the contact between the electric wires.

In the latter case, the rubber / plastic coated electric wire in which the identification body 33 is embedded in the surface layer portion of the rubber / plastic layer 34 has a rubber / plastic layer 3 around the core wire (conductor) 32.
When the identification body 33 to be embedded after extrusion molding 4 is extruded, the pressure applied from the outside around the core wire (conductor) 32 becomes non-uniform, and the core wire (conductor) 32 is There is a problem that the electrical characteristics are easily deteriorated because the core 32 (conductor) 32 is eccentric and the cross-sectional shape of the conductor (conductor) 32 is easily flat.

Therefore, the present invention solves the above-mentioned problems, the identification body is not easily damaged, the formation of the identification body is not performed in a separate step, and the rubber / plastic covered electric wire excellent in electrical characteristics and the production thereof are provided. A method and a manufacturing apparatus thereof are provided.

[0007]

In order to solve the above-mentioned problems, the invention of claim 1 is a rubber-plastic coated electric wire in which the periphery of a conductor is extruded with a rubber-plastic layer, wherein the rubber-plastic layer is identified. A rubber comprising a rubber / plastic inner layer having a protrusion forming a body and a rubber / plastic outer layer covering the periphery of the rubber / plastic inner layer to expose at least a part of the protrusion. -It is a plastic covered electric wire.

A second aspect of the invention is the rubber-plastic coated electric wire according to the first aspect, wherein the protrusion is continuous in the longitudinal direction of the conductor.

A third aspect of the present invention is the rubber / plastic covered electric wire according to the first aspect, wherein the thickness of the rubber / plastic outer layer is 0.02 mm or more.

According to a fourth aspect of the present invention, in a method for producing a rubber / plastic covered electric wire in which a conductor is extruded around a rubber / plastic layer, a rubber / plastic inner layer having a protruding portion forming an identification body on the outer periphery of the conductor. A rubber / plastic coated electric wire, wherein a rubber / plastic outer layer is integrally extruded around the rubber / plastic inner layer in order to expose and identify at least a part of the protrusion when the rubber is extruded. Is a manufacturing method.

According to a fifth aspect of the present invention, there is provided an apparatus for manufacturing a rubber / plastic covered electric wire having a die comprising a mandrel for inserting a core wire and a cap for extruding a rubber / plastic layer on the core wire. Rubber that has a protrusion that forms an identifier at the boundary between the front part and the rear part of the base.
An inner layer forming die portion is formed to extrude a plastic inner layer on the outer periphery of the core wire, and along the circumferential direction of the die surface, at least a part of the protruding portion is exposed,
The rubber / plastic coated electric wire is characterized in that the outer layer forming groove is discontinuously formed so as to extrude the rubber / plastic outer layer covering the rubber / plastic inner layer.

According to a sixth aspect of the present invention, the depth and shape of the groove portion are adjusted so that the rubber / plastic molten resin forming the rubber / plastic outer layer is extruded into the die with uniform pressure. This is a rubber / plastic coated electric wire manufacturing device.

According to the above structure, the rubber / plastic layer is formed by surrounding the rubber / plastic inner layer having the protrusions forming the identifying body and the rubber / plastic inner layer so as to expose at least a part of the protrusions. Since it is composed of a coated rubber / plastic outer layer, the identifier is not easily damaged, and its formation is not performed in a separate step, and
It is possible to obtain a rubber / plastic coated electric wire having excellent electrical characteristics.

[0014]

Embodiments of the present invention will be described below.

Rubber / plastic coated electric wire 1 of the present invention
Is a rod-shaped core wire (conductor) 2 as shown in FIG.
The core 3 is covered with a rubber / plastic inner layer 3 having a projection 3a continuous in the longitudinal direction of the core 2 and the projection 3a is formed.
In order to expose at least a part (only the surface of the protrusion in the figure) of the above, the periphery of the rubber / plastic inner layer 3 is covered with the rubber / plastic outer layer 4.

The rubber / plastic inner layer 3 and the rubber / plastic outer layer 4 are formed of rubber / plastic (for example, polyethylene) of different colors,
The protruding portion 3a of the rubber / plastic inner layer 3 becomes a color band in the rubber / plastic coated electric wire 1.

Although the constituent materials of the rubber / plastic inner layer 3 and the rubber / plastic outer layer 4 are not particularly limited,
Polyethylene, cross-linked polyethylene, polyvinyl chloride or the like is preferable.

The cross-sectional shape of the projection 3a has a width such that the exposed side of the projection 3a (projection surface in the figure) can be identified as a color band, and the inner surface of the rubber / plastic 3 of the projection 3a is the same. There is no particular limitation as long as the connection side has a width capable of maintaining good connection strength.

Although the height of the exposed portion of the protruding portion 3a in the rubber / plastic coated electric wire 1 is not particularly limited, it is necessary to prevent a step from being formed between the exposed portion of the protruding portion 3a and the rubber / plastic outer layer 4. Is desirable.

Next, the manufacturing method and apparatus of the present invention will be described.

As shown in FIG. 6, the core wire 2 is inserted from the insertion opening 5a.
And insert the rubber / plastic coated wire 1 from the outlet 5b.
In the head 5 of an extruder (not shown) for injecting the rubber, a rubber / plastic molten resin (for example, molten polyethylene) _IP is introduced into the die 8 from a first molten resin pressure inlet 6 provided on the side of the head 5. And a rubber / plastic inner layer 3 is formed on the outer circumference of the core wire 2, and the second molten resin pressure inlet 7 provided on the side of the head 5 presses the rubber
Plastic molten resin (eg, molten polyethylene) O
_P is press-fitted into the die 8 to coat the outer circumference of the rubber / plastic inner layer 3 with the rubber / plastic outer layer 4 to produce the rubber / plastic coated electric wire 1.

At this time, as shown in FIG. 7 which is an enlarged view of a main part of the die 8 in FIG. 6, rubber / plastic molten resin I _P is press-fitted from a first molten resin pressurizing port (not shown),
The rubber / plastic inner layer 3 in the inner layer forming mouthpiece portion 9 formed at the boundary between the mouthpiece front portion (outlet side; left side portion in the figure) 8b and the mouthpiece rear portion (insertion mouth side; right side portion in the figure) 8c.
To form The second molten resin pressure inlet by press-fitting (not shown) of the rubber-plastic melt resin O _P, mouthpiece front portion 8b groove 10 slits for discontinuously formed outer layer formed in the circumferential direction on the surface of the The rubber / plastic outer layer 4 is formed by extruding to the position of the inner layer forming die portion 9 through 10b.

After that, a head insertion opening 5a (not shown)
The core wire 2 which is inserted from the core wire 8a and pulled out from the core wire 8a is simultaneously covered with the rubber / plastic inner layer 3 and the rubber / plastic outer layer 4 formed in the inner layer forming die portion 9 and is subjected to a drawing process by a die 8. It becomes the rubber / plastic covered electric wire 1.

In the present invention, the rubber / plastic molten resin O _P is extruded from the outer layer forming groove portion 10 so that at least a part of the protruding portion 3a is exposed as shown in FIG. -The outer plastic layer 4 is covered.

8 (a) and 8 (b) are schematic views of the mouthpiece in the rubber / plastic coated electric wire manufacturing apparatus of the present invention. 8C is a developed view of the outer layer forming groove portion in FIGS. 8A and 8B.

As shown in FIGS. 8A to 8C, the outer layer forming groove portion 10 is formed discontinuously along the circumferential direction of the surface of the die 8b according to the number of the protruding portions 3a. , 0.5 mm to rubber & plastics molten resin injected from the rubber and plastics molten resin pressure inlet 10a O _P is extruded at equivalent pressures to the slit 10b, a predetermined depth (e.g., the depth of the portion of the X , The Y portion has a depth of 1 mm, and the X portion has a greater depth than the Y portion) and has a predetermined shape.

Further, as shown in FIGS. 9 and 10, the longitudinal sectional view of FIG. 8A and the view taken along the line AA of FIG. 7 show the rubber / plastic molten resin I forming the rubber / plastic inner layer 3. _P is extruded to the position of the inner layer forming die portion 9 inside the die 8b. At this time, the rubber / plastic outer layer 4 is formed from the slits 10b of the outer layer forming groove 10 formed discontinuously along the circumferential direction on the surface of the die 8b.
Since the plastic molten resin O _P is extruded into the base 8b, the rubber / plastic inner layer 3 surrounds the core 8a through which the core wire 2 is inserted, and at the same time, the rubber / plastic outer layer 4 covering the rubber / plastic inner layer 3 is formed. In the figure, the protrusions 3a (two in the figure) are partially (the protrusions 3a in the figure).
(Exposed surface only) is exposed.

Next, another embodiment of the present invention will be described.

As another embodiment of the rubber / plastic-coated electric wire, as shown in FIG. 2, a core wire (conductor) 12, a rubber / plastic inner layer 13, a rubber / plastic outer layer 1
4, the protrusion 13a is longer on the rubber / plastic inner layer 13 side, and the rubber / plastic outer layer 1
A rubber / plastic covered electric wire 11 having an isosceles trapezoidal shape with a short 4 side is conceivable. As a result, the angle formed by the boundary between the layer portion of the rubber / plastic inner layer 13 and the protrusion 13a becomes an obtuse angle, so that the stress applied to the boundary is relaxed, and the layer portion of the rubber / plastic inner layer 13 and the protrusion 13a are relaxed.
The joint strength with

Similarly, as shown in FIG. 3, the core wire (conductor)
The rubber / plastic coating has an isosceles trapezoidal shape in which the protrusions 23a are short on the rubber / plastic inner layer 23 side and long on the rubber / plastic outer layer 24 side, while maintaining the arrangement structure of the rubber 22, plastic inner layer 23, and rubber / plastic outer layer 24. The electric wire 21 is conceivable. As a result, the width of the color band in the rubber / plastic covered electric wire 21 is widened, so that the identification can be performed more easily.

[0031]

【Example】

(Example 1) A rubber / plastic inner layer made of polyethylene and having a protrusion continuous in the longitudinal direction of the conductor was formed around a Cu conductor having a diameter of about 0.5 mm by 0.19 mm.
And a polyethylene / rubber / plastic outer layer with a thickness of 0.06 mm around the inner surface of the rubber / plastic to expose only the surface of the protrusion. A rubber / plastic coated electric wire was produced.

The height of the protrusion of the rubber / plastic coated electric wire from the rubber / plastic inner layer is 0.06.
mm, the width was about 0.3 mm.

(Comparative Example 1) A rubber / plastic layer made of polyethylene was coated around a Cu conductor having a diameter of about 0.5 mm to a thickness of 0.25 mm. As a result, a rubber / plastic body made of polyethylene was embedded by exposing only the surface, and a rubber / plastic covered electric wire having an outer diameter of about 1 mm was produced.

The width of the rubber / plastic body in this rubber / plastic-coated electric wire was set to about 0.3 mm.

Here, the cross-sectional structure of the rubber / plastic coated electric wire of Example 1 is as shown in FIG. 1, and the cross-sectional structure of the rubber / plastic coated electric wire of Comparative Example 1 is as shown in FIG.

The rubbers obtained in Example 1 and Comparative Example 1
The distribution of the eccentricity and the flatness of the plastic coated wire was investigated. The results are shown in FIGS. 4 and 5.

The horizontal axis in FIG. 4 represents the eccentricity of the rubber / plastic coated electric wire, and the vertical axis represents the distribution ratio thereof. The horizontal axis in FIG. 5 represents the flatness of the rubber / plastic coated electric wire, and the vertical axis represents its distribution.

In this embodiment, the curve (a) in FIG. 4 and the curve in FIG.
As shown by the curve (c) in (1), it can be seen that the eccentricity and the flatness have small variations, and the eccentricity and the flatness are unlikely to occur.

On the other hand, in the comparative example, the curve (b) in FIG.
Further, as shown in FIG. 5D, it is understood that the eccentricity and the flatness vary widely, and the eccentricity and the flatness are likely to occur.

[0040]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) The core wire (conductor) is covered with a rubber / plastic inner layer having a protrusion forming an identification body, and the rubber / plastic inner layer is covered with a rubber to expose at least a part of the protrusion. -Because it is covered with a plastic outer layer, the identification body is not easily damaged, and a rubber / plastic coated electric wire with a narrow eccentricity and flatness distribution and excellent electrical characteristics can be obtained.

(2) When the rubber / plastic inner layer having the protruding portion forming the identification body is extrusion-molded, the rubber / plastic outer layer is formed of the rubber / plastic outer layer so as to identify at least a part of the protruding portion. Since the extrusion molding is performed integrally around the inner layer, the rubber / plastic covered electric wire can be continuously manufactured, and the manufacturing cost can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing an overview of a rubber / plastic-coated electric wire of the present invention.

FIG. 2 is a diagram showing an example of a cross section of a rubber / plastic covered electric wire according to another embodiment.

FIG. 3 is a view showing an example of a cross section of a rubber / plastic covered electric wire according to another embodiment.

FIG. 4 is a diagram showing an example of the relationship between the eccentricity and its distribution in the rubber / plastic coated electric wire of the present invention.

FIG. 5 is a diagram showing an example of the relationship between the flatness rate and the distribution rate thereof in the rubber / plastic-coated electric wire of the present invention.

FIG. 6 is a diagram showing a vertical cross section of the rubber / plastic coated electric wire manufacturing apparatus of the present invention.

FIG. 7 is a diagram showing an enlarged main part of a die in the rubber / plastic covered electric wire manufacturing apparatus of the present invention.

FIG. 8 is a view showing an outline of a mouthpiece in the rubber / plastic coated electric wire manufacturing apparatus of the present invention.

9 is a view showing a vertical cross section of the die in FIG.

FIG. 10 is a view of the die of FIG. 7 taken along the line AA.

FIG. 11 is a view showing a cross section of a conventional rubber / plastic covered electric wire.

[Explanation of symbols]

1,11,21 Rubber / plastic coated electric wire 2,12,22 Core wire (conductor) 3,13,23 Rubber / plastic inner layer (rubber / plastic layer) 3a, 13a, 23a Protrusion (rubber / plastic layer) 4, 14, 24 Rubber / plastic outer layer (rubber / plastic layer) 8 Die 8a Mandrel 8b Mouth front part 8c Mouth rear part 9 Inner layer forming mouthpiece 10 Outer layer forming groove 10a Rubber / Plastic molten resin pressure inlet 10b Slit _IP rubber plastic molten resin O _P rubber and plastics molten resin

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Wataru Nakatani 5-1-1 Hidaka-cho, Hitachi-shi, Ibaraki Hitachi Cable Co., Ltd. Hidaka factory

Claims (6)

[Claims] 1. In a rubber / plastic covered electric wire in which a conductor is extruded around a rubber / plastic layer, the rubber / plastic layer includes a rubber / plastic inner layer having a protrusion forming an identification body, and a protrusion of the rubber / plastic inner layer. A rubber / plastic covered electric wire comprising a rubber / plastic outer layer covering the periphery of the rubber / plastic inner layer so as to expose at least a part thereof. 2. The rubber / plastic covered electric wire according to claim 1, wherein the protrusion is continuous in the longitudinal direction of the conductor. 3. The thickness of the rubber / plastic outer layer is:
The rubber / plastic covered electric wire according to claim 1, which has a thickness of 0.02 mm or more. 4. A method for producing a rubber / plastic covered electric wire in which a conductor is extruded around a rubber / plastic layer, wherein a rubber / plastic inner layer having a protrusion forming an identification body is extruded on the outer periphery of the conductor. A method for manufacturing a rubber / plastic covered electric wire, characterized in that a rubber / plastic outer layer is integrally extruded around the rubber / plastic inner layer in order to expose and identify at least a part of the protrusion. 5. A mandrel for inserting the core wire and rubber for the core wire.
In a rubber / plastic coated electric wire manufacturing apparatus having a die including a die for extrusion molding a plastic layer, at a boundary between a front portion of the die and a rear portion of the die,
An inner layer forming die portion is formed to extrude a rubber / plastic inner layer having a protruding portion forming an identification body on the outer periphery of the core wire, and at least one of the protruding portions is formed along the circumferential direction of the die surface. An apparatus for producing a rubber / plastic coated electric wire, characterized in that a groove portion for forming an outer layer is formed discontinuously so as to extrude a rubber / plastic outer layer covering the rubber / plastic inner layer while exposing the portion. 6. The rubber / plastic coating according to claim 5, wherein the depth and shape of the groove portion are adjusted so that the rubber / plastic molten resin forming the rubber / plastic outer layer is extruded into the die with a uniform pressure. Electric wire manufacturing equipment.