JP2014157709A - Insulation cable and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insulation cable which can prevent infiltration of water from the end surface of an insulation member while suppressing cost increase, and a method for manufacturing the insulation cable.SOLUTION: An insulation cable 1 comprises a pair of conductors 21, 22, and an insulation member 3 which covers the pair of conductors 21, 22. The insulation member 3 includes a porous resin layer 31 in which vacancies 310 are formed, an outer peripheral skin layer 32 which prevents infiltration of water from the outer peripheral surface of the insulation member 3, and an end skin layer 33 which prevents infiltration of water from the end surface in the longitudinal direction of the insulation member 3. The end skin layer 33 is formed by heat-melting a part of the porous resin layer 31.

Description

  The present invention relates to an insulated cable in which a conducting wire is covered with an insulating member and a method for manufacturing the same.

  Conventionally, an insulated cable is known in which a conductor is covered with a foamed insulator and a non-foamed skin layer is provided on the outer periphery of the foamed insulator (see, for example, Patent Documents 1, 2, and 3).

  These insulating cables use a resin material in which a large number of holes are formed by foaming as an insulator, thereby reducing the dielectric constant of the insulator and enabling high-speed signal transmission. Further, the penetration of moisture into the holes from the outer periphery of the insulated cable is suppressed by the skin layer.

JP-A-6-290644 Japanese Unexamined Patent Publication No. 7-6663 JP-A-11-120828

  In these insulated cables, moisture permeation from the outer periphery of the insulated cable is suppressed by the skin layer, but a large number of holes are exposed to the outside of the skin layer on the end surface of the foamed insulator in the longitudinal direction of the insulated cable. Therefore, there is a possibility that moisture may enter from this end face.

  The relative dielectric constant of water is, for example, 80.4 at 20 ° C., which is higher than the relative dielectric constant of air (1.0). Therefore, when moisture enters the pores, the dielectric constant of the foamed insulator increases. Thereby, the signal transmission characteristic of an insulated cable will deteriorate. This deterioration in signal transmission characteristics can be a big problem especially in recent high-speed communications (for example, communications of 1 Gbps or more).

  Further, in order to prevent moisture from entering from the end face of the foamed insulator, for example, it is conceivable to seal the end face of the foamed insulator with a water-resistant resin. The cost increases greatly due to an increase in materials and man-hours for sealing.

  Then, an object of this invention is to provide the manufacturing method of the insulated cable which can prevent the penetration | invasion of the water | moisture content from the end surface of an insulating member, and the insulated cable, suppressing the raise in cost.

  In order to solve the above-described problems, the present invention includes a conductive wire and an insulating member that covers the conductive wire, and the insulating member includes a porous resin layer in which pores are formed, and an outer periphery of the insulating member. An outer peripheral skin layer that prevents moisture from entering from the surface, and an end skin layer that prevents moisture from entering from the longitudinal end face of the insulating member, and the end skin layer is formed of the porous resin layer. Provided is an insulated cable that is partially melted by heat.

  In addition, in order to solve the above-mentioned problems, the present invention heats the conducting wire led out from the insulating member, so that a part of the porous resin layer at the end in the longitudinal direction of the insulating member is formed. Provided is a method for manufacturing an insulated cable, which is melted to form the end skin layer.

  According to the insulated cable and the method for manufacturing the same according to the present invention, it is possible to prevent moisture from entering from the end face of the insulating member while suppressing an increase in cost.

The external view which shows the edge part vicinity of the insulated cable which concerns on the 1st Embodiment of this invention. (A) is the sectional view on the AA line of FIG. (B) is the BB sectional drawing of FIG. The formation process of the edge part skin layer of an insulated cable is shown, (a) is a perspective view, (b) is CC sectional view taken on the line of (a). The external view which shows the edge part vicinity of the insulated cable which concerns on 2nd Embodiment. (A) is the DD sectional view taken on the line of FIG. (B) is the EE sectional view taken on the line of FIG. The formation process of the end part skin layer of an insulated cable is shown, (a) is a perspective view which shows the state before formation of an end part skin layer, (b) is the end surface of the insulation member which shows the state after formation of an end part skin layer Figure. The insulated cable which concerns on 3rd Embodiment is shown, (a) is an external view which shows an edge part vicinity, (b) is an end elevation. Explanatory drawing which shows the manufacturing process of the insulated cable which concerns on 4th Embodiment.

[First Embodiment]
FIG. 1 is an external view showing the vicinity of an end of an insulated cable according to a first embodiment of the present invention. FIG. 2A is a cross-sectional view taken along line AA in FIG. FIG. 2B is a sectional view taken along line BB in FIG.

  The insulated cable 1 includes a pair of conducting wires 21 and 22 and an insulating member 3 that collectively covers the pair of conducting wires 21 and 22. As shown in FIG. 2A, the insulating member 3 includes a porous resin layer 31 that covers the outer periphery of the pair of conductive wires 21 and 22, and an outer peripheral skin layer 32 as an outer peripheral skin layer. Fine pores 310 are formed in the porous resin layer 31. The outer peripheral skin layer 32 covers the outer peripheral side of the porous resin layer 31 and prevents moisture from entering from the outer peripheral side of the insulating member 3.

  The pair of conductive wires 21 and 22 are made of metal wires such as tin-plated annealed copper wires, for example, and are arranged in parallel to each other. The conducting wires 21 and 22 are preferably stranded wires, but may be single wires. If the conducting wires 21 and 22 are stranded wires, the flexibility of the insulated cable 1 can be increased. As the conductors 21 and 22, a conductor whose conductor size is thinner than 24AWG (conductor diameter 0.51 mm) can be suitably used. The pair of conductive wires 21 and 22 transmit a differential signal having a communication speed of 1 Gbps or more, for example.

  As the porous resin layer 31, for example, a resin such as polyethylene or PTFE (polytetrafluoroethylene) that is foamed by including thermally expandable hollow spheres can be used. As the thermally expandable hollow sphere, for example, a shell composition of methyl methacrylate acrylonitrile, an encapsulant of isobutane, and a particle size of 32 to 62 μm can be used. Further, as the porous resin layer 31, a water-absorbing polymer swollen by water supply may be dispersed in an ultraviolet curable resin composition and then dehydrated.

  The porous resin layer 31 includes a large number of pores 310 formed as described above, and the porosity in the volume is, for example, 30% or more and 70% or less. In FIG. 2, the pores 310 are schematically shown, but the porous resin layer 31 has a water absorption structure in which a large number of pores 310 communicate with each other to absorb moisture.

  The outer peripheral skin layer 32 is formed by, for example, extruding a non-foamed resin material selected from high density polyethylene, polypropylene, polymethylpentene-1, polyimide (nylon), and polyester on the outer periphery of the porous resin layer 31 with an extruder. Formed.

  In addition, as shown in FIG. 2B, the insulating member 3 has an end skin layer 33 as an end skin layer that prevents moisture from entering from the end surface 3 a in the longitudinal direction of the insulating member 3. The end skin layer 33 is formed by melting a part of the porous resin layer 31 with heat. In the process in which the porous resin layer 31 is melted, the pores 310 disappear due to the flow of the liquid molten resin in which the porous resin layer 31 is melted, so that the end skin layer 33 is waterproof. That is, the end portion in the longitudinal direction of the porous resin layer 31 is covered with the end portion skin layer 33 over the entire portion, so that the intrusion of moisture into the porous resin layer 31 is suppressed.

  As shown in FIG. 2 (a), the insulating member 3 has an outer peripheral surface 3b in a cross section perpendicular to the longitudinal direction thereof, curved in a convex arc shape and continuous, and a parallel direction of the pair of conductors 21 and 22 Is an ellipse having a width in the first direction that is greater than the width in the second direction orthogonal to the first direction. In the example shown in FIG. 2A, the cross-sectional shape of the insulating member 3 is an elliptical shape.

  The insulating member 3 has a width in the first direction of, for example, 1 mm to 5 mm, and a width in the second direction of, for example, 0.5 mm to 2.5 mm.

  Next, an example of a method for manufacturing the insulated cable 1 will be described with reference to FIG. 3A and 3B show a process of forming the end skin layer 33 of the insulated cable 1, wherein FIG. 3A is a perspective view, and FIG. 3B is a cross-sectional view taken along the line CC of FIG.

  In this step, by heating the pair of conductive wires 21 and 22 led out from the insulating member 3, a part of the porous resin layer 31 at the end in the longitudinal direction of the insulating member 3 is melted, and the end skin layer 33. Form.

  More specifically, the pair of conducting wires 21 and 22 led out from the insulating member 3 are heated by the heating jig 6 in the vicinity of the insulating member 3, and the porous resin is formed by heat conduction through the pair of conducting wires 21 and 22. A part of the layer 31 is melted. The heating jig 6 includes a first heating member 61 and a second heating member 62 that are relatively movable, and by sandwiching the pair of conductors 21 and 22 by the first heating member 61 and the second heating member 62, A pair of conducting wires 21 and 22 are heated.

  The first heating member 61 and the second heating member 62 are heated to a temperature (for example, 350 ° C. or higher) higher than the temperature at which the porous resin layer 31 melts by a heat source such as a heating wire (not shown). This heat source may be provided only on one of the first heating member 61 and the second heating member 62. For example, when the heat source is provided only in the first heating member 61, the second heating member 62 is desirably a material having a lower thermal conductivity than the first heating member 61.

  The heat of the pair of conductors 21 and 22 heated by the heating jig 6 generates a liquid molten resin in which a part of the porous resin layer 31 is melted. Thereafter, the temperature of the molten resin is lowered and solidified, whereby the end skin layer 33 is formed.

  The distance between the position where the pair of conducting wires 21 and 22 is heated and the end surface of the porous resin layer 31 may be a distance at which the porous resin layer 31 is melted by heat conduction through the pair of conducting wires 21 and 22.

  In addition, although FIG. 3 demonstrates the case where a pair of conducting wire 21 and 22 is heated by the heating jig 6 simultaneously, for example, a part of the porous resin layer 31 is formed by heating only one conducting wire 21. It may be melted. Moreover, after heating one conducting wire 21, the other conducting wire 22 may be heated.

(Operation and effect of the first embodiment)
According to the first embodiment described above, the following operations and effects can be obtained.

(1) Since the penetration of moisture from the end face 3a of the insulating member 3 is suppressed by the end skin layer 33, the penetration of moisture into the porous resin layer 31 increases the dielectric constant in the porous resin layer 31. Can be prevented. Thereby, deterioration of the signal transmission characteristic of the insulated cable 1 can be suppressed.

(2) Since the end skin layer 33 is formed by melting a part of the porous resin layer 31, for example, a waterproof treatment is performed by covering the end surface of the porous resin layer 31 with another resin member or the like. Compared to the case, an increase in cost can be suppressed.

(3) Since the porous resin layer 31 is heated by heat conduction from the pair of conductive wires 21 and 22, only the porous resin layer 31 in the vicinity of the end in the longitudinal direction of the insulating member 3 is partially heated. Can do. Thereby, compared with the case where hot air is applied, for example to the insulating member 3, and the porous resin layer 31 is heated, it can suppress that the part which is not intended melt | dissolves.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. 4 to 6, members having substantially the same functions as those described in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  FIG. 4 is an external view showing the vicinity of the end of the insulated cable 1A according to the second embodiment. Fig.5 (a) is the DD sectional view taken on the line of FIG. FIG.5 (b) is the EE sectional view taken on the line of FIG.

  Insulated cable 1A according to the present embodiment includes shield layer 4 covering the outer peripheral side of outer peripheral skin layer 32 of insulating member 3 in addition to the pair of conductive wires 21 and 22 and insulating member 3, and the outer peripheral side of shield layer 4 And a covering jacket 5.

  The shield layer 4 is formed, for example, by spirally winding or longitudinally winding a tape-shaped member in which a highly conductive metal foil such as copper is integrated with a belt-shaped resin member around the insulating member 3. The jacket 5 is made of a flexible insulator such as a fluororesin, and is formed in a cylindrical shape. The shield layer 4 has an outer peripheral surface 4 a exposed from the jacket 5 at the end in the longitudinal direction of the insulated cable 1 </ b> A.

  In the present embodiment, the end skin layer 33 of the insulating member 3 heats the end of the insulating member 3 in the longitudinal direction from the outer peripheral side via the shield layer 4 to melt a part of the porous resin layer 31. It is formed by. Therefore, the end skin layer 33 is in contact with the inner peripheral surface 4b of the shield layer 4 as shown in FIG. The end skin layer 33 covers the entire end of the insulating member 3 inside the shield layer 4.

  6A and 6B show a process of forming the end skin layer 33 of the insulated cable 1A, (a) is a perspective view showing a state before the end skin layer 33 is formed, and (b) is a view after the end skin layer 33 is formed. It is an end view of the insulating member 3 which shows the state.

  Insulated cable 1 </ b> A is formed by soldering shield layer 4 to electrode 71 formed on substrate 7. That is, the end skin layer 33 is formed by melting a part of the porous resin layer 31 by heat when soldering the metal foil of the shield layer 4 and the electrode 71. At this time, since the end skin layer 33 is formed over the entire end of the insulating member 3, it is desirable that the contact surface between the shield layer 4 and the solder 72 be as wide as possible. For this reason, it is desirable that the width of the electrode 71 along the first direction is wider than the width of the insulating member 3 in the first direction along the parallel direction of the pair of conductive wires 21 and 22.

(Operation and effect of the second embodiment)
According to the second embodiment described above, in addition to the operations and effects of (1) and (2) described for the first embodiment, the shield effect by the shield layer 4 can be obtained, and the end skin Since the layer 33 is in contact with the shield layer 4, it is possible to prevent moisture from entering between the outer skin layer 32 and the shield layer 4 and the signal transmission characteristics of the insulated cable 1 </ b> A from being deteriorated by this moisture.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. In FIG. 7, members and the like having substantially the same functions as those described in the first and second embodiments are denoted by the same reference numerals and description thereof is omitted.

  7A and 7B show an insulated cable 1B according to the third embodiment. FIG. 7A is an external view showing the vicinity of the end of the insulated cable 1B, and FIG. 7B is an end view.

  Like the insulated cable 1A according to the second embodiment, the insulated cable 1B includes a pair of conductors 21 and 22, an insulating member 3, a shield layer 4, and a jacket 5, but the shield layer 4 The configuration in which the connection member 8 is further provided outside is different from the insulated cable 1A according to the second embodiment. The connection member 8 is for connecting the shield layer 4 to another conductor such as a grounded ground line.

  The connecting member 8 is formed by bending a highly conductive metal plate such as copper or aluminum, for example, and has a main body 81 soldered to the outer peripheral surface at the end of the shield layer 4 and 2 protruding from the main body 81. One protrusion 82 is integrally formed. The main body 81 is formed in a shape surrounding the shield layer 4 from three sides, and protrusions 82 are formed at two locations sandwiching the pair of conductive wires 21 and 22. Each protrusion 82 protrudes in a direction parallel to the direction in which the pair of conducting wires 21 and 22 from the insulating member 3 is led out. The protrusion 82 is connected to, for example, a grounded ground line or a ground pattern of the substrate by soldering.

  The end face of the insulating member 3 in the longitudinal direction of the insulated cable 1B is formed by the end skin layer 33. The end skin layer 33 is formed by melting a part of the porous resin layer 31 by heat when the main body 81 of the connection member 8 and the shield layer 4 are connected by the solder 80. That is, the end skin layer 33 melts a part of the porous resin layer 31 by heat when soldering the main body 81 of the connection member 8 and the shield layer 4 in the manufacturing process of the insulated cable 1B. Is formed by. The end skin layer 33 is formed over the entire end of the insulating member 3, and the peripheral edge thereof is in contact with the shield layer 4.

(Operation and effect of the third embodiment)
According to the third embodiment described above, the same operations and effects as those described for the second embodiment can be obtained. Moreover, the operation | work which electrically connects the shield layer 4 to another conductor becomes easy.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described with reference to FIG. In FIG. 8, members and the like having substantially the same functions as those described in the first embodiment are denoted by the same reference numerals and description thereof is omitted. This embodiment is different from the first embodiment in the method for manufacturing the insulated cable 1.

  FIG. 8 is an explanatory view showing a manufacturing process of the insulated cable 1 according to the fourth embodiment.

  In the present embodiment, a part of the porous resin layer 31 is formed by cutting the insulating member 3 with the first and second blades 91 and 92 heated to a temperature higher than the melting temperature of the porous resin layer 31. The end skin layer 33 (see FIG. 2) is formed by melting. Thereby, the insulated cable 1 of the structure similar to what is shown in FIG.1 and FIG.2 is obtained.

  The first cutting tool 91 has semicircular cutouts 91 a and 91 b formed in the blade edge portion 911. The interval between the notches 91a and 91b is an interval adapted to the interval between the pair of conductors 21 and 22. Further, the second cutting tool 92 is formed with semicircular cutouts 92 a and 92 b in the blade edge portion 921. The interval between the notches 92a and 92b is the same as the interval between the notches 91a and 91b of the first blade 91.

  The arc radii of the notches 91a and 91b of the first cutting tool 91 and the arc radii of the notches 92a and 92b of the second cutting tool 92 are substantially equal to the radii of the first and second conductors 21 and 22 or the first radius. And a dimension slightly larger than the radius of the second conductive wires 21 and 22.

  The first blade 91 and the second blade 92 are heated to a temperature (for example, 350 ° C. or higher) higher than the temperature at which the porous resin layer 31 melts by a heat source such as a heating wire (not shown). The insulating member 3 sandwiched between the first blade tool 91 and the second blade tool 92 is caused by bringing the first blade tool 91 and the second blade tool 92 close to each other with the blade edge portions 911 and 921 facing each other. Disconnected. At this time, due to the heat of the first cutting tool 91 and the second cutting tool 92, a part of the porous resin layer 31 in contact with the first cutting tool 91 or the second cutting tool 92 is melted, and the end skin layer 33 is formed. It is formed.

  On the other hand, the first and second conducting wires 21 and 22 are not cut because they are accommodated in the notches 91a and 91b and the notches 92a and 92b. And by moving the 1st blade tool 91 and the 2nd blade tool 92 along the 1st and 2nd conducting wires 21 and 22 in the state where blade edge parts 911 and 921 were contacted, the 1st Insulated cable 1 having the same configuration as the embodiment is obtained.

(Operation and effect of the fourth embodiment)
According to the fourth embodiment described above, in addition to the operations and effects of (1) and (2) described for the first embodiment, a part of the insulating member 3 is removed to remove the first and first. The operation of exposing the two conductive wires 21 and 22 and the operation of forming the end skin layer 33 can be performed in one step. Thereby, manufacture of the insulated cable 1 can be performed at lower cost.

(Summary of embodiment)
Next, the technical idea grasped from the embodiment described above will be described with reference to the reference numerals in the embodiment. However, the reference numerals and the like in the following description are not intended to limit the constituent elements in the claims to the members and the like specifically shown in the embodiments.

[1]: a conductive wire (21, 22) and an insulating member (3) that covers the conductive wire (21, 22), and the insulating member (3) is porous in which pores (310) are formed. Resin layer (31), outer peripheral skin layer (32) that prevents moisture from entering from the outer peripheral surface of insulating member (3), and an end that prevents moisture from entering from the end surface in the longitudinal direction of insulating member (3) An insulation cable (1, 1A, 1B) formed by melting part of the porous resin layer (31) by heat. ).

[2]: A shield layer (4) covering the outer peripheral side of the outer peripheral skin layer (32) is further provided, and the end skin layer (33) is in contact with the shield layer (4). [1] Insulated cable (1A, 1B).

[3] A connecting member (8) having a main body (81) soldered to the outer peripheral surface at the end of the shield layer (4) and a protrusion (82) protruding from the main body (81). The insulated cable (1B) according to [2], further provided.

[4]: A method for manufacturing an insulated cable (1, 1A, 1B) according to any one of [1] to [3], wherein the conducting wire (21, 21) led out from the insulating member (3) is provided. 22) is heated to melt part of the porous resin layer (31) at the longitudinal end of the insulating member (3) to form the end skin layer (33). A manufacturing method of (1, 1A, 1B).

[5]: The method for manufacturing an insulated cable (1, 1A, 1B) according to any one of [1] to [3], wherein the insulating member (3) is attached to the porous resin layer (31). By cutting with a cutting tool (91, 92) heated to a temperature higher than the melting temperature of, to melt a part of the porous resin layer (31) to form the end skin layer (33), Manufacturing method of insulated cable (1, 1A, 1B).

[6]: The method for manufacturing an insulated cable (1A, 1B) according to [2] or [3], wherein an end portion in the longitudinal direction of the insulating member (3) is interposed through the shield layer (4). A method for manufacturing an insulated cable (1A, 1B), in which the end skin layer (33) is formed by heating from the outer peripheral side to melt a part of the porous resin layer (31).

[7]: The method for manufacturing the insulated cable (1B) according to [3], wherein the heat at the time of soldering the main body portion (81) of the connection member (8) and the shield layer (4) is provided. The method for manufacturing an insulated cable (1B), wherein a part of the porous resin layer (31) is melted to form the end skin layer (33).

  While the embodiments of the present invention have been described above, the embodiments described above do not limit the invention according to the claims. In addition, it should be noted that not all the combinations of features described in the embodiments are essential to the means for solving the problems of the invention.

  Further, the present invention can be appropriately modified and implemented without departing from the spirit of the present invention. For example, in each of the above-described embodiments, the case where the insulated cables 1, 1A, 1B have the two conducting wires 21, 22 has been described. However, the number of conducting wires provided in the insulated cable is not limited to this. Three or more may be used. Further, the insulating member 3 may include other layers in addition to the porous resin layer 31, the outer peripheral skin layer 32, and the end skin layer 33. There is no particular limitation on the use of the insulated cable.

DESCRIPTION OF SYMBOLS 1,1A, 1B ... Insulated cable, 3 ... Insulating member, 3a ... End surface, 3b ... Outer peripheral surface, 4 ... Shield layer, 4a ... Outer peripheral surface, 4b ... Inner peripheral surface, 5 ... Jacket, 6 ... Heating jig, 7 DESCRIPTION OF SYMBOLS ... Board | substrate, 8 ... Connection member, 21, 22 ... Conductor, 31 ... Porous resin layer, 32 ... Outer peripheral skin layer, 33 ... End part skin layer, 61 ... 1st heating member, 62 ... 2nd heating member, 71 ... Electrode, 72, 80 ... solder, 81 ... main body, 82 ... projection, 91 ... first blade, 92 ... second blade, 310 ... hole, 911,921 ... blade

Claims (7)

A conductive wire and an insulating member covering the conductive wire;
The insulating member is
A porous resin layer in which pores are formed;
An outer peripheral skin layer for preventing moisture from entering from the outer peripheral surface of the insulating member;
An end skin layer that prevents moisture from entering from the longitudinal end face of the insulating member;
The end skin layer is an insulated cable formed by melting a part of the porous resin layer by heat. Further comprising a shield layer covering the outer peripheral side of the outer peripheral skin layer,
The end skin layer is in contact with the shield layer;
The insulated cable according to claim 1. A main body portion soldered to the outer peripheral surface of the end portion of the shield layer, and a connecting member having a protrusion protruding from the main body portion;
The insulated cable according to claim 2. A method for manufacturing an insulated cable according to any one of claims 1 to 3,
By heating the conductive wire led out from the insulating member, a part of the porous resin layer at the end in the longitudinal direction of the insulating member is melted to form the end skin layer.
Insulated cable manufacturing method. A method for manufacturing an insulated cable according to any one of claims 1 to 3,
By cutting the insulating member with a blade heated to a temperature higher than the melting temperature of the porous resin layer, a part of the porous resin layer is melted to form the end skin layer.
Insulated cable manufacturing method. A method for producing an insulated cable according to claim 2 or 3,
Heating the end of the insulating member in the longitudinal direction from the outer peripheral side through the shield layer, and melting the part of the porous resin layer to form the end skin layer;
Insulated cable manufacturing method. A method for producing an insulated cable according to claim 3,
The end skin layer is formed by melting part of the porous resin layer by heat when soldering the main body portion of the connection member and the shield layer.
Insulated cable manufacturing method.

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