JP2020009686A - Waterproof connection structure for electric wire and waterproof connection method for electric wire - Google Patents

Abstract

To provide a waterproof connection structure for an electric wire that, even in a case where it is left in a high-temperature environment for a long time, prevents deterioration of protection of a conductor part and the function of insulation, resulting from displacement of a heat-shrinkable tube covering a conductor exposed portion, including a splice part, and exposure of the conductor part, and to provide a waterproof connection method for an electric wire.SOLUTION: A waterproof connection structure for an electric wire comprises: a splice part 10 formed in a conductor exposed portion 42 and away inwards from a leading end 42a of the conductor exposed portion 42, the conductor exposure portion formed at a terminal from which an insulation coating 43 on a plurality of electric wires 40 is removed, the plurality of electric wires having a conductor part 41 covered with the insulation coating 43, the conductor part being a bundle of strands 41a; a strand spreading part 20 in which the plurality of strands 41a from the splice part 10 to the leading end 42a are spread outward beyond a cross-section of the splice part 10 in a cross-sectional direction; and a heat-shrinkable tube 30 attached to the plurality of electric wires 40 so as to cover the conductor exposed portion 42 including the strand spreading part 20, and having a hot-melt layer 31 provided on an internal surface 30a thereof.SELECTED DRAWING: Figure 4

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a waterproof connection structure of an electric wire and a waterproof connection method of the electric wire for waterproofing a conductor exposed portion where a plurality of electric wires are connected to each other.

Conventionally, when a plurality of electric wires of a wire harness routed to an automobile are electrically connected to each other as branch connection portions of a circuit, a conductor portion is exposed by removing an insulating coating of a terminal portion of the plurality of electric wires. The exposed conductors are connected to each other.
When such a wire harness is mounted on a vehicle, a conductor is protected and insulated by mounting a heat-shrinkable tube so as to cover a conductor exposed portion including a connection portion of a plurality of electric wires.

  For example, in Patent Literature 1, a core-concentrated splice portion (splice portion) is formed on a conductor exposed portion of a terminal portion from which an insulating coating has been removed, and a plurality of electric wires connected to each other by forming a core-concentrated splice portion (splice portion). A waterproof connection structure of an electric wire is described in which a heat-shrinkable tube provided with a hot-melt layer on its inner surface is covered so as to cover a conductor exposed portion including a splice portion.

JP-A-11-233175

  However, the waterproof connection structure of the electric wire described in Patent Document 1 has a problem that when left in a high-temperature environment in which the hot-melt layer melts for a long time, the hot-melt layer on the inner surface of the heat-shrinkable tube melts and heat shrinks. When the tube shrinks and shifts from a predetermined mounting position, the conductor is exposed, and as a result, the function of protecting and insulating the conductor may be impaired.

  The present invention has been made in view of the above, and even when left in a high-temperature environment for a long time, the heat-shrinkable tube covering the conductor-exposed portion including the splice is shifted to expose the conductor. It is an object of the present invention to provide a waterproof connection structure for electric wires and a method for waterproof connection of electric wires, which can prevent the functions of protecting and insulating the conductor portion from being impaired.

  In order to solve the above-mentioned problem and achieve the object, a waterproof connection structure for an electric wire according to claim 1 of the present invention is a waterproof connection structure for a plurality of electric wires in which a conductor portion in which a plurality of strands are bundled is surrounded by an insulating coating. The conductor-exposed portion of the terminal portion from which the insulating coating has been removed, a splice portion formed at a position inwardly away from the tip of the conductor-exposed portion so that the plurality of wires are connected to each other, and from the splice portion. The plurality of strands up to the distal end are separated from each other by the splice section, and the plurality of strands are connected to each other at the splice section. A heat-shrinkable tube attached to the electric wire so as to cover the exposed portion of the conductor including the splice portion and the unraveled wire portion, and having a hot melt layer provided on an inner surface thereof. Characteristic To.

  Further, in the waterproof connection structure for an electric wire according to claim 2 of the present invention, in the above-described invention, the heat-shrinkable tube pushes against the element wire of the wire-expanding portion that is abutted against the inner surface by shrinkage. It is characterized by having strength not to be broken.

  In order to solve the above-described problems and achieve the object, a waterproof connection method for an electric wire according to claim 3 of the present invention is a method of connecting a plurality of electric wires in which a conductor portion in which a plurality of wires are bundled is surrounded by an insulating coating. A splice portion forming step of forming a splice portion at a position inwardly away from a tip of the conductor exposed portion so that the plurality of electric wires are connected to each other on the conductor exposed portion of the terminal portion where the insulating coating has been removed, A wire solution in which the plurality of wires from the splice portion of the conductor-exposed portion to the tip end are spread outward in the cross-sectional direction of the splice portion outside the cross-section to form a wire solution forming an enlarged portion The expanding step and the heat-shrinkable tube provided with a hot melt layer on the inner surface, the plurality of electric wires connected to each other at the splice part, the splice part and the strand including the unraveled enlarged part are included. A heat-shrinkable tube mounting step of mounting to cover the body-exposed portion, and a heat-shrinkable tube heating step of applying heat to shrink the heat-shrinkable tube to the heat-shrinkable tube mounted in the heat-shrinkable tube mounting step, It is characterized by including.

In the waterproof connection structure of the electric wire according to the present invention, the heat-shrinkable tube mounted so as to cover the exposed portion of the conductor including the splice portion and the wire breaking and expanding portion, the heat-shrinkable tube from the splice portion to the tip end. A plurality of strands are separated from each other in the direction of the cross section of the splice portion so as to extend outward from the cross section, and are hooked on the respective strands of the enlarged portion.
For this reason, the waterproof connection structure of the electric wire according to the present invention, the hot melt layer is melted by being left for a long time in a high temperature environment where the hot melt layer melts, and the heat shrinkable tube shrinks. Even if the heat-shrinkable tube attempts to shift from the predetermined mounting position, the wire breaking and expanding portion is caught on the inner surface of the heat-shrinkable tube, thereby preventing the heat-shrinkable tube from moving from the predetermined mounting position. it can.
Thereby, the waterproof connection structure of the electric wire according to the present invention, even when left in a high-temperature environment for a long time, the heat-shrinkable tube covering the exposed portion of the conductor including the splice is displaced to expose the conductor. This can prevent the functions of protecting and insulating the conductor from being impaired.

In the method for waterproofly connecting an electric wire according to the present invention, in the splice portion forming step, the conductor exposed portion may be formed from the splice portion by forming the splice portion at a position inward from a tip of the conductor exposed portion. In the section up to the tip, the plurality of strands are in an easy-to-understand state.
Further, the waterproof connection method of the electric wire according to the present invention is characterized in that, in the unraveling step, the splice portion forming step allows the wire to be easily unraveled in a section from the splice portion to the tip of the conductor exposed portion. By unraveling the plurality of strands so that the tips extend outward from the cross-section in the cross-sectional direction of the splice with the splice part as the base, the strands can be easily unraveled to form an enlarged portion.
Further, in the method for waterproofly connecting an electric wire according to the present invention, in the heat-shrinkable tube mounting step, the heat-shrinkable tube is connected to the plurality of electric wires connected to each other at the splice portion, and the strand is expanded and expanded. After covering the exposed portion of the conductor including the heat-shrinkable tube in the heat-shrinkable tube heating step, the heat-shrinkable tube is followed by the portion covered with the heat-shrinkable tube, so that the wire is unfolded and enlarged. The part is hooked on the heat-shrinkable tube further than the state of the heat-shrinkable tube mounting step.
Thus, the waterproof connection method of the electric wire according to the present invention, even when left in a high-temperature environment for a long time, the heat-shrinkable tube covering the conductor-exposed portion including the splice portion is displaced and the conductor Exposure of the portion can prevent the function of protecting and insulating the conductor portion from being impaired.

FIG. 1 is a view of a waterproof structure of an electric wire according to an embodiment of the present invention, as viewed from above a splice portion in a state where a heat-shrinkable tube is viewed in cross section. FIG. 2 is a diagram of the conductor exposed portion including the splice portion and the insulating coating around the conductor exposed portion as viewed from above the splice portion. FIG. 3 is a cross-sectional view of the heat-shrinkable tube. 4A is a diagram for explaining a splice portion forming process, FIG. 4B is a diagram for explaining an enlarging process by unraveling wires, and FIG. 4C is a diagram for explaining a heat shrink tube mounting process. It is a figure for demonstrating, (d) is a figure for demonstrating a heat-shrinkable tube heating process.

  Hereinafter, preferred embodiments of a waterproof connection structure for an electric wire and a waterproof connection method for an electric wire according to the present invention will be described in detail with reference to the drawings.

FIG. 1 is a diagram of a waterproof structure 1 of an electric wire according to an embodiment of the present invention as viewed from above a splice portion 10 in a state where a heat-shrinkable tube is viewed in cross section. FIG. 2 is a view of the conductor exposed portion 42 including the splice portion 10 and the insulating coating 43 around the conductor exposed portion 42 as viewed from above the splice portion 10. FIG. 3 is a sectional view of the heat-shrinkable tube 30.
The waterproof connection structure 1 of the electric wire according to the embodiment of the present invention is used, for example, as a branch connection portion of a plurality of electric wires 40 of a wire harness routed in a vehicle, outdoors, particularly in a place where it is left for a long time in a high-temperature environment. It is arranged in.

  The waterproof connection structure 1 of the electric wire includes a conductor exposed portion 42 of a terminal portion in which the insulating coating 43 of the plurality of electric wires 40 in which the conductor portion 41 in which the plural wires 41 a are bundled is surrounded by the insulating coating 43 is removed. A splice portion 10 formed so that a plurality of electric wires 40 are connected to each other; a wire breaking enlarged portion 20 in which a plurality of wires 41a from the splice portion 10 to a tip 42a of the conductor exposed portion 42 are formed; And a heat-shrinkable tube 30 provided with a hot-melt layer 31 on 30a.

First, the splice unit 10 will be described.
The splice portion 10 is a portion to which the conductor portions 41 of the plurality of electric wires 40 are connected by, for example, thermocompression bonding (diffusion bonding), welding bonding, or ultrasonic bonding. In this embodiment, the conductor portions 41 of the plurality of electric wires 40 are connected to the splice portion 10 by thermocompression bonding.
In this embodiment, the conductor portion 41 of the electric wire 40 is a portion constituting a core wire in which a plurality of conductive wires 41a made of aluminum, copper, or the like are bundled.
In this embodiment, three wires 40 are connected to each other. However, the number of wires 40 to be connected to each other is not limited to this, and may be two or three or more.

  The splice portion 10 is configured such that the conductor portions 41 exposed at the terminal portions of the plurality of electric wires 40 are brought into close contact with each other, and are crimped while heating using a press (not shown), so that the plurality of electric wires 40 It is the connected part.

In addition, the splice portion 10 includes a plurality of conductors 41 in which a plurality of strands 41a are bundled, and a plurality of wires 40 surrounded by the insulating coating 43. The electric wires 40 are formed at positions separated inward from the distal end 42a of the conductor exposed portion 42 so as to be connected to each other.
For this reason, in the section from the splice part 10 formed in the conductor exposed part 42 to the tip 42a of the conductor exposed part 42, the plurality of strands 41a can be easily unraveled.

Next, the element dissolving and enlarging unit 20 will be described.
The wire breaking and expanding portion 20 is a portion where the plurality of wires 41a from the splice portion 10 to the tip end 42a of the conductor exposed portion 42 are spread in the cross section direction of the splice portion 10 outward from the cross section. is there.
The unfolded and enlarged portion 20 is a portion that is hooked on the heat-shrinkable tube 30 in a state where the heat-shrinkable tube 30 is mounted.
Such a wire breaking and enlarging portion 20 is left for a long time in a high temperature environment where the hot melt layer melts, so that the hot melt layer 31 on the inner surface 30a of the heat shrink tube 30 melts, When the contraction of the heat-shrinkable tube 30 is attempted to move from the predetermined mounting position due to contraction, the heat-shrinkable tube 30 is prevented from moving from the predetermined mounting position by being caught on the inner surface 30 a of the heat-shrinkable tube 30.

Next, the heat-shrinkable tube 30 will be described.
The heat-shrinkable tube 30 is a bottomed tubular member made of a heat-shrinkable insulating material, and has a hot-melt layer 31 provided on the inner surface.
Note that the heat-shrinkable tube 30 may be a tubular member without a bottom.

  The heat-shrinkable tube 30 has a plurality of electric wires 40 connected to each other at the splice portion 10, a conductor exposed portion 42 including the splice portion 10 and the unfolded enlarged portion 20, and a periphery of the conductor exposed portion 42. The conductor portion 41 is mounted so as to cover a region surrounded by the insulating coating 43.

  In addition, the heat-shrinkable tube 30 has a strength such that the wires abutted against the inner surface 30 a by the shrinkage are not broken by the wires 41 a of the enlarged portion 20.

Next, a waterproof connection method of an electric wire according to an embodiment of the present invention will be described with reference to FIG.
4A is a diagram for explaining a splice portion forming process, FIG. 4B is a diagram for explaining an enlarging process by unraveling wires, and FIG. 4C is a diagram for explaining a heat shrink tube mounting process. It is a figure for demonstrating, (d) is a figure for demonstrating a heat-shrinkable tube heating process.

First, as a splice part forming step, a splice part 11 to be a connection part of the electric wire 40 is formed (see FIG. 4A).
In this splice portion forming step, a plurality of conductors 41 in which a plurality of strands 41a are bundled are surrounded by an insulating coating 43. The splice portion 10 is formed at a position inwardly away from the distal end 42a of the exposed conductor portion 43 so that the electric wires 40 are connected to each other.
In the splice portion forming step, the conductor portions 41 of the conductor exposed portions 42 of the plurality of electric wires 40 from which the insulation coating of the terminal portions has been removed are brought into close contact with each other, and are pressed while heating using a press (not shown). Thus, the splice portion 10 is formed.
In the splice portion forming step, the splice portion 10 is formed by thermocompression bonding (diffusion bonding). However, the splice portion 10 is not limited to this, and the splice portion 10 may be formed by welding or ultrasonic bonding. Good.

Next, as a strand disassembling and expanding step, a plurality of strands 41a from the splice portion 10 to the tip 42a of the conductor exposed portion 42 are displaced so as to extend outward from the cross section in the cross section direction of the splice portion 10. Then, the enlarged portion 20 is formed (see FIG. 4B).
In the wire breaking and expanding step, the plurality of wires 41a are broken with the crimped splice portion 10 as the root, and the ends of the wires 41a are spread outward from the cross section in the cross section direction of the splice portion 10. Can be expanded as follows.

Next, as a heat-shrinkable tube mounting step, the heat-shrinkable tubes 30 are mounted on the plurality of electric wires 40 connected to each other at the splice portion 10 (see FIG. 4C).
In the heat shrink tube mounting step, the conductor exposed portion 42 including the splice portion 10 and the wire unfolding portion 20 and the conductor exposed portion 42 are provided for the plurality of electric wires 40 connected to each other at the splice portion 10. The conductor portion 41 is mounted so as to cover the area surrounded by the peripheral insulating coating 43.
By this heat shrink tube mounting step, the strands 41a of the unraveled and enlarged portion 20 are accommodated in the heat shrink tube 30 in a state where the strands 41a of the splice portion 10 extend outward from the cross section in the cross section direction.

Finally, as a heat-shrinkable tube heating step, the heat-shrinkable tube 30 is contracted by applying high-temperature heat to the attached heat-shrinkable tube 30 (see FIG. 4D).
In the heat-shrinkable tube heating step, the heat-shrinkable tube 30 is shrunk by applying high-temperature heat to the attached heat-shrinkable tube 30, and the hot-melt layer 31 provided on the inner surface 30 a of the heat-shrinkable tube 30 is melted. .
By shrinking the heat-shrinkable tube 30 in this manner, the heat-shrinkable tube 30 follows the portion covered by the heat-shrinkable tube 30.
After being melted, the hot melt layer 31 is filled between the inner surface 30 a of the heat-shrinkable tube 30 and a portion covered by the heat-shrinkable tube 30 and solidified.
In the heat-shrinkable tube heating step, the heat-shrinkable tube 30 follows the portion covered by the heat-shrinkable tube 30, so that the heat-shrinkable tube 30 is disentangled and hooked on the enlarged portion 20.

In the waterproof connection structure 1 for an electric wire according to the embodiment of the present invention, the heat-shrinkable tube 30 mounted so as to cover the conductor exposed portion 42 including the splice portion 10 and the unraveled enlarged portion 20 is separated from the splice portion 10. The plurality of strands 41a up to the distal end 42a are separated from each other in such a manner as to extend outward from the cross section in the direction of the cross section of the splice part 10, and are hooked on the respective strands 41a of the enlarged part 20.
For this reason, when the waterproof connection structure 1 for an electric wire according to the present invention is left for a long time in a high temperature environment where the hot melt layer 31 melts, the hot melt layer 31 melts and the heat shrink tube 30 shrinks. Even if the heat-shrinkable tube 30 attempts to move from the predetermined mounting position, the strands are unraveled and the enlarged portion 20 is caught on the inner surface 30a of the heat-shrinkable tube 30, thereby preventing the heat-shrinkable tube 30 from moving from the predetermined mounting position. Can be.
As a result, even when the waterproof connection structure 1 for an electric wire according to the present invention is left in a high-temperature environment for a long time, the heat-shrinkable tube 30 covering the conductor exposed portion 42 including the splice portion 10 is displaced and the conductor By exposing the portion 41, it is possible to prevent the protection and insulation functions of the conductor portion 41 from being impaired.

  In the waterproof connection structure 1 of the electric wire according to the embodiment of the present invention, the heat-shrinkable tube 30 is broken by the wire 41a of the enlarged portion 20 which is broken by the contraction and the inner surface 30a of the heat-shrinkable tube 30. Since it has a strength that does not occur, it is possible to effectively function the unraveled and enlarged portion 20 as a hooked portion of the heat-shrinkable tube 30.

The waterproof connection method for an electric wire according to the embodiment of the present invention includes the steps of: forming a splice portion 10 at a position inwardly away from a tip 42a of a conductor exposed portion 42 in a splice portion forming step; A plurality of strands 41a are in a state where they can be easily unraveled in a section up to the tip 42a of the exposed portion 42.
Further, in the waterproof connection method of the electric wire according to the present invention, in the strand unraveling step, a plurality of strands 41a in a state that is easy to unravel in a section from the splice part 10 to the tip 42a of the conductor exposed part 42 are spliced. By expanding the outer periphery of the splice portion 10 outward from the cross-section in the cross-sectional direction of the splice portion 10 with the base 10 as the base, the enlarged portion 20 can be easily formed by breaking the wires.
Further, in the method for waterproofly connecting electric wires according to the present invention, in the heat-shrinkable tube mounting step, the heat-shrinkable tube 30 is disassembled into a plurality of electric wires 40 connected to each other by the splice portion 10 and the enlarged portion 20 is disassembled. By mounting so as to cover the conductor exposed portion 42 including the wire, the wire can be disentangled and the enlarged portion 20 can be easily caught on the heat-shrinkable tube 30.
Further, in the waterproof connection method of the electric wire according to the present invention, in the heat-shrinkable tube heating step, the heat-shrinkable tube 30 follows the portion covered with the heat-shrinkable tube 30, thereby disassembling the wire and expanding the enlarged portion 20. Thus, the heat-shrinkable tube 30 can be more easily hooked on the heat-shrinkable tube 30 than in the heat-shrinkable tube mounting step.
Accordingly, in the waterproof connection method of the electric wire according to the present invention, the heat-shrinkable tube 30 covering the conductor exposed portion 42 including the splice portion 10 is displaced even when the wire is left in a high-temperature environment for a long time. Exposure of 41 prevents loss of the protection and insulation functions of conductor 41.

  As described above, the invention made by the inventor has been specifically described based on the embodiments of the above-described invention. However, the present invention is not limited to the above-described embodiments of the invention, and does not depart from the gist of the invention. Can be variously changed.

DESCRIPTION OF SYMBOLS 1 Waterproof connection structure of an electric wire 10 Splice part 20 Unwrapped and enlarged part 30 Heat shrinkable tube 30a Inner surface 31 Hot melt layer 40 Electric wire 41 Conductor part 41a Elementary wire 42 Conductor exposed part 42a Tip 43 Insulation coating

Claims (3)

The conductor-exposed portion is formed such that the plurality of wires are connected to each other at a conductor-exposed portion of a terminal portion from which the insulation coating is removed of a plurality of wires in which a conductor portion in which a plurality of strands are bundled is surrounded by an insulation coating. A splice portion formed inwardly away from the tip of the
An element dissolving and expanding part in which the plurality of element wires from the splice part to the tip end are expanded so as to extend outward from the cross section in the cross section direction of the splice part.
The plurality of electric wires connected to each other at the splice portion are attached so as to cover the exposed portions of the conductor including the splice portion and the unraveled wire portion, and a hot melt layer is provided on the inner surface. Heat shrink tubing,
A waterproof connection structure for electric wires, comprising: The heat-shrinkable tube is
The waterproof connection structure for an electric wire according to claim 1, wherein the wire has a strength that does not break through the wire of the enlarged portion where the wire hits the inner surface due to contraction. The conductor-exposed portion is formed such that the plurality of wires are connected to each other at a conductor-exposed portion of a terminal portion from which the insulation coating is removed of a plurality of wires in which a conductor portion in which a plurality of strands are bundled is surrounded by an insulation coating. A splice portion forming step of forming a splice portion at a position inward from the tip of the splice portion,
A wire solution in which the plurality of wires from the splice portion of the conductor-exposed portion to the tip end are spread outward in the cross-sectional direction of the splice portion outside the cross-section to form a wire solution forming an enlarged portion Expansion process,
A heat-shrinkable tube provided with a hot-melt layer on the inner surface covers the conductor-exposed portion including the splice portion and the unwrapped enlarged portion with respect to the plurality of electric wires connected to each other at the splice portion. Heat shrink tube mounting process
A heat-shrinkable tube heating step of applying heat to shrink the heat-shrinkable tube to the heat-shrinkable tube mounted in the heat-shrinkable tube mounting step;
A waterproof connection method for electric wires, comprising:

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