JP2000243151A - Airtight electric wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an airtight electric wire capable of surely preventing oil or water from invading into the interior of the wire by capillary phenomena or leaking out from a terminal part of the wire, facilitating termination work, and excelling in productivity. SOLUTION: This airtight electric wire is made up of a stranded wire conductor 1 having airtight parts 1b formed in at least a part thereof in the longitudinal direction and an insulator 2 covering the outer circumference thereof. The stranded wire conductor 1 is formed by stranding a plurality of conductor element wires together with fiber bundles made of thermoplastic resin so that the conductor element wires are disposed at least in the outermost layer. In the airtight parts 1b in the stranded wire conductor 1, the thermoplastic resin melted by heating the fiber bundles is applied between conductor element wires.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention can surely prevent oil or water from penetrating into a wire or leaking from a wire terminal due to a capillary phenomenon, and can easily process a terminal and have excellent productivity. Related to airtight electric wires.

[0002]

2. Description of the Related Art In electric wires used as lead wires of various devices, a stranded conductor obtained by twisting a plurality of conductor strands is used as a conductor for the purpose of improving the flexibility. Usually, this kind of electric wire is subjected to an appropriate terminal processing according to various uses after removing an insulator at a terminal portion and exposing a stranded wire conductor, and is provided for actual use.
At this time, if oil, water, or the like is present near the end of the electric wire, they propagate inside the conductor by capillary action and penetrate in the longitudinal direction of the electric wire, causing various problems. Such a phenomenon occurs, for example, when used in an environment where there is a pressure difference between both ends of an electric wire, such as a lead wire used in an oil case of an automatic transmission of an automobile. Especially remarkable.

[0003] Conventionally, as means for preventing oil or water from entering the inside of an electric wire and leaking oil from an end portion of the electric wire, for example, as disclosed in Japanese Patent Publication No. 1-59476, an electric wire is disclosed. A method in which a wire having a conductor exposed portion is arranged inside a wire holding case for fixing the wire to an oil case, and a thermosetting resin such as an epoxy resin is filled between exposed conductor wires of the wire, or a patent Publication No. 282514
As disclosed in Japanese Unexamined Patent Publication No. 3 (1999) -2003, a terminal holding plate formed by sealing between a terminal insertion hole of a board on which a plurality of terminals are mounted and the terminal by soldering is formed integrally with a cylindrical housing. A method of using a connector in which a sealing member for preventing liquid leakage is attached to an electric wire introduction portion of the cylindrical housing, or a stranded wire as an electric wire as disclosed in Japanese Patent Application Laid-Open No. 10-269861. A method has been proposed in which a conductor having a configuration in which a watertight material such as a polyethylene resin is filled in an outer peripheral surface and a gap of each conductor element constituting a conductor is proposed.

[0004]

However, first of all,
In the case of the method disclosed in Japanese Patent Publication No. 1-59476, since a thermosetting resin such as an epoxy resin used as a filler does not follow thermal expansion or thermal shrinkage and easily cracks. Depending on the case, there was a fear that an oil leak would occur. To solve this problem, for example, Japanese Patent No. 2766558 proposes an oil leakage prevention wire holding case that can use a resin material that has good followability and is hard to crack. As with the connector disclosed in the above-mentioned Japanese Patent Publication No. 2825143, such an electric wire holding case has a problem that the cost is increased because the shape is very complicated and special.

[0005] Next, in the case of using a wire having a structure in which a watertight material is filled in the outer peripheral surface and gaps of a conductor strand as disclosed in Japanese Patent Application Laid-Open No. 10-269681, the watertight material is made of a conductor. Because it is hardened in the state where it adheres to the strand, for example, when connecting a crimp terminal to the end of the wire, it is necessary to remove the watertight material firmly adhered to the conductor strand,
There was a problem that it took a long time to process the terminal.

The present invention has been made based on such a point, and an object of the present invention is to surely prevent oil or water or the like from entering the inside of an electric wire by capillary action or leaking from an end of the electric wire. An object of the present invention is to provide an inexpensive hermetic electric wire which can be prevented, is easily processed at the end, and has excellent productivity.

[0007]

Means for Solving the Problems To achieve the above object, an airtight electric wire according to the present invention comprises a stranded conductor having an airtight portion formed in at least a part of its length, and an insulator coated on the outer periphery thereof. An airtight electric wire consisting of:
A plurality of conductor strands and a fiber bundle made of thermoplastic resin are formed by twisting at least the outermost layer so that the conductor strands are arranged, and in the hermetic portion of the stranded conductor, In addition, a thermoplastic resin melted by heating the fiber bundle is filled between the conductor strands.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The constituent material of the conductor strand is not particularly limited, and any known conductor material can be used.

The fiber bundle made of a thermoplastic resin used in the present invention is a bundle of thermoplastic resin fibers. Various types of thermoplastic resin fibers have been conventionally known, and examples thereof include polyester fibers, polyvinylidene fluoride fibers, polyvinylidene chloride fibers, polypropylene fibers, polyethylene fibers, and polyamide fibers. These are the use conditions (use, required functions, etc.) of the electric wire obtained by the present invention, the type of insulator described later,
What is necessary is just to select suitably according to the formation method (heating method etc.) of an airtight part.

The insulator is formed by extrusion-coating various known insulating coating materials on a stranded conductor using a known extruder. Depending on the type of insulating coating material, the insulator is appropriately crosslinked. Processing is performed. The type of the insulating coating material is selected in consideration of the usage conditions (application, required functions, and the like) of the electric wire obtained by the present invention, and is not particularly limited.

In the present invention, the fiber bundle made of the thermoplastic resin and the conductor strand are twisted at least so that the conductor strand is arranged on the outermost layer to form a stranded conductor. At this time, it is conceivable that the conductor strands arranged in the outermost layer are compressed in the radial direction so as to be in close contact with each other. In this way, when forming an airtight portion in the stranded conductor, it is possible to effectively prevent the thermoplastic resin melted by heating the fiber bundle from flowing out from the gap between the conductor strands, and the terminal It is not necessary to remove the resin material attached to the conductor wires during processing or the like.
The compression processing of the conductor strand may not be performed at the time of forming the stranded conductor, but may be performed while applying a predetermined pressure at the time of forming the hermetic portion after the formation of the stranded conductor.

The airtight portion is for preventing oil and water from entering the inside of the electric wire due to capillary action, and preventing oil and water from entering the inside of the electric wire from leaking from the end portion of the electric wire. By heating and melting the plastic resin fiber bundle, it is formed in at least a part (a part, a plurality of parts, or the whole) in the length direction of the stranded conductor. Whether this hermetic part is formed in a part of the stranded conductor, or formed in multiple parts,
Whether it is formed entirely is determined in consideration of the use conditions (use, required functions, etc.) of the electric wire obtained by the present invention, and is not particularly limited. Further, the forming method is not particularly limited, and various methods can be considered.

For example, a method of heating at least a part of the length of the stranded conductor before coating with an insulator by various heating devices to melt the thermoplastic resin fiber bundle, and a method of extruding and coating the insulator. A method of melting the thermoplastic resin fiber bundle by continuously heating the stranded wire conductor in the length direction by heat, heating the thermoplastic resin fiber bundle by heating at least a part of the length direction of the electric wire after forming the insulator. In the case of performing a method of melting and heat-crosslinking the insulator, a method of melting the thermoplastic resin fiber bundle by the heat is used. These methods are an example of a forming method at the time of manufacturing an electric wire.In addition to these methods, for example, when forming an assembly by performing terminal processing on an electric wire cut to a predetermined length. Conceivable.

For example, when the terminal processing is performed, a method of heating the insulation barrel portion of the connection terminal with various heating devices to melt the thermoplastic resin fiber bundle, at least a part of the wire assembly in the length direction is used. A method in which a thermoplastic resin fiber bundle is melted by caulking with a caulking metal fitting that has been heated in advance, a bushing is formed by molding at a predetermined position in the length direction of the wire assembly, and the heat of the injection resin at that time is formed. And a method of melting the thermoplastic resin fiber bundle by pressure and pressure. Among these methods, in the case of forming the crimped portion on at least a part of the wire assembly, even if the stranded conductor is not compressed in advance, the diameter of each conductor strand is increased by the pressure applied at the time of crimping. Direction.

[0015]

EXAMPLES Examples of the present invention will be described below together with comparative examples. In this example, a tin-plated soft copper wire was used as the conductor wire. In addition, a polyethylene terephthalate fiber bundle was used as the thermoplastic resin fiber bundle.

Example 1 Sixteen tinned annealed copper wires having a wire diameter of 0.18 mm and a melting point of 2
After twisting three bundles of polyethylene terephthalate fiber at a pitch of 7.0 mm at 60 ° C. and a thickness of 500 denier such that tin-plated soft copper wires are arranged on the outermost layer, the tin-plated soft copper wires arranged on the outermost layer are joined together. Were compressed in the radial direction so as to be in close contact with each other to form a stranded conductor having an outer diameter of 0.825 mm. Next, a fluororubber mixture was added to the stranded conductor in a volume of 0.1 mm.
An insulator was formed by extrusion coating with a thickness of 4 mm, and crosslinked by a known method to obtain an electric wire having a finished outer diameter of 1.7 mm. Lastly, a polyethylene terephthalate fiber bundle was heated and melted by applying hot air at 300 ° C. for 20 seconds to a portion of the wire surface having a width of 20 mm to form an airtight portion. In the present example, this operation was repeated while leaving an interval of 300 mm in the length direction of the electric wire, and an airtight electric wire having a plurality of airtight portions formed in the length direction was manufactured. FIG. 1 is a cross-sectional view of the hermetic wire of the hermetic wire obtained in this manner. here,
Reference numeral 1 denotes a stranded conductor, reference numeral 1a denotes a conductor strand, reference numeral 1b denotes an airtight portion, and reference numeral 2 denotes an insulator.

Comparative Example In this example, without using the polyethylene terephthalate fiber bundle used in the example, 19 tin-plated annealed copper wires each having a strand diameter of 0.18 mm were twisted and then radially compressed to form an outer layer. A stranded conductor having a diameter of 0.825 mm was formed. Next, a fluororubber mixture was extrusion-coated on the stranded wire conductor with a thickness of 0.4 mm to form an insulator, cross-linked by a known method, and having a finish outer diameter of 1.7 mm as shown in FIG. I got the wires. In FIG. 2, reference numeral 11 denotes a stranded conductor, reference numeral 11a denotes a conductor strand, and reference numeral 12 denotes an insulator.

Here, the above two types of electric wires are used as samples.
The airtightness, oil leakage, and terminal workability (terminal workability) were evaluated. The evaluation method is as follows. The evaluation results are shown in Table 1.

One end of a sample cut to an airtight length of 500 mm has 2.0 kgf
/ Cm ² was applied, and the amount of air leaked from the other end of the sample was measured for 5 minutes. One end of the sample cut into a leaky length of 500 mm is immersed in oil, a pressure of 2.0 kgf / cm ² is applied to the oil surface, and the amount of oil leaked from the other end of the sample in 24 hours is measured. did. The test oil used was Nissan Matic Fluid D oil. Terminal Workability (Terminal Workability) With respect to the sample according to this example, the portion of the insulator where the airtight portion was formed was stripped, and the state of attachment of the thermoplastic resin to the surface of the stranded conductor was visually checked. For the sample according to the comparative example, the insulator at an arbitrary position in the length direction was set to have a width of 2
After stripping by 0 mm, the state of adhesion of the insulating coating material to the surface of the stranded conductor was visually checked.

[0020]

[Table 1]

As a result, air leakage and oil leakage were confirmed in the electric wire of the comparative example, whereas no air leakage and oil leakage were confirmed in the electric wire according to the present embodiment. That is, it was found that the electric wire according to the present example is an electric wire that can surely prevent oil, water, and the like from entering the inside of the electric wire due to the capillary phenomenon and leaking from the end of the electric wire.
In addition, the wire according to the present embodiment has a terminal workability (terminal workability).
Also, no resin was attached to the surface of the stranded conductor at all, and the wire had the same workability as the electric wire of the comparative example.

[0022]

As described above in detail, the hermetic electric wire of the present invention is provided with an hermetic part formed by heating and melting a thermoplastic resin fiber bundle at least in a part of the length of the stranded conductor. Therefore, it is possible to reliably prevent oil, water, and the like from entering the inside of the electric wire due to the capillary phenomenon and leaking from the end of the electric wire. In addition, the end processing is easy, and the wire can be easily manufactured by the same method as in the case of manufacturing a normal electric wire, so that it can be provided at low cost. Therefore, for example, it can be suitably used in a wide range of applications such as a lead wire arranged in an oil case of an automatic transmission of an automobile.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention, and is a cross-sectional view of an airtight electric wire.

FIG. 2 is a view showing a comparative example, and is a cross-sectional view of an electric wire in which an airtight portion is not formed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Twisted wire conductor 1a ... Conductor strand 1b ... Airtight part 2 ... Insulator

Claims (1)

[Claims] 1. An airtight electric wire comprising a stranded conductor having an airtight portion formed in at least a part of a length direction thereof, and an insulator coated on an outer periphery of the stranded conductor. A conductor strand and a fiber bundle made of a thermoplastic resin are formed by twisting at least on the outermost layer so that the conductor strand is arranged, and the above-described fiber is formed in an airtight portion of the stranded conductor. An airtight electric wire characterized in that a thermoplastic resin melted by heating a bundle is filled between conductor wires.