JP2013017286A - Waterproofing method and waterproof structure for electric wire terminal splice portion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase waterproofing accuracy and cut waste of a cap and a water sealing agent, in a water sealing method in which an electric wire terminal splice portion is accommodated in the cap and embedded in the water sealing agent to be hardened inside the cap.SOLUTION: A cap, in which a stop valve provided with a water sealing agent injection hole in a penetrating manner is tightly fitted and fixed to an opening at one end of a heat-shrinkable tube, is used; a splice portion is inserted into the cap; the heat-shrinkable tube is shrunk after the insertion of the splice portion; and subsequently, the water sealing agent is pressurized and injected into the cap from the water sealing agent injection hole provided in the stop valve.

Description

  The present invention relates to a waterproof method and a waterproof structure for a wire terminal splice, and more specifically, inserts a terminal splice that is welded by overlapping core wires exposed at a plurality of wire ends into an insulating resin cap, and into the cap. It is embedded in a waterproofing agent to be filled and waterproofed.

  There are many electric wires that form a branch circuit by being connected to each other in an electric wire group that constitutes a wire harness routed to an automobile or the like. When it is necessary to connect a large number of electric wires, the electric wires are peeled off from the insulating coating layer at the ends to expose the core wires, and the exposed core wires are collectively welded to form terminal splice portions. .

  As a waterproofing method for the terminal splice part, the present applicant provides a waterproofing method shown in FIG. 4 in Japanese Patent Laid-Open No. 2006-81319. In the waterproofing method, a cap 100 which is closed by inserting a stopper 102 into one end opening of the heat shrinkable tube 101 is provided, a fixed amount of a water-stopping agent 110 is injected into the cap 100, and then a terminal splice 120 is inserted. Then, the heat-shrinkable tube 110 of the cap 100 is heated and contracted at a required temperature, and the water-stopper 110 is also thermally cured.

  The water-stopping agent 110 is injected before the terminal splice part 120 is inserted into the cap 100. When the heat-shrinkable tube 101 of the cap 100 is heat-shrinked, the inlet 100h of the cap 100 becomes narrow and is inserted into the cap 100. This is because the bundled electric wires 121 continuing to the terminal splice 120 are blocked by the inlet 100h and the water stop agent 110 cannot be injected. Moreover, even in the state before the heat-shrinkable tube 101 is heated and shrunk, the opening area of the inlet of the cap 100 becomes very narrow with the bundled electric wires 121, and the gap into which the water-stopping agent 110 can be injected is reduced. This is because the injection is not easy and there is a problem that it easily spills.

JP 2006-81319 A

  In the waterproofing method of Patent Document 1, since the terminal splice part 120 is inserted in a state where a fixed amount of the water stop agent 110 is injected into the cap 100 in advance, the water stop agent 110 when the wire bundle of the terminal splice part 120 is large. The liquid level rises. Therefore, if the water-stopping agent overflows from the cap and adheres to other products, a wiping work is required. Therefore, it is necessary to lengthen the length of the cap 100 to, for example, 60 mm or more so that the water-stopping agent does not overflow, and there is a problem in that the material cost is increased and the cap itself is lengthened to take a space.

  Furthermore, after the terminal splice part 120 is inserted into the cap 100, the cap 100 is heated at a temperature at which the cap 100 can be thermally contracted. As shown in FIG. 5, there is a possibility that the lower part of the cap 100 swells into a bowl shape. In that case, there is a possibility that the exposed core wire or insulation coating portion of each electric wire 121 continuing to the terminal splice portion 120 may not be completely buried in the water stop agent 110, and there is a problem that reliability of water stop accuracy is lowered. is there.

  The present invention is intended to solve the above problem, and the exposed core wire of the terminal splice part and each electric wire continuous to the splice part can be surely buried in the water-stopping agent, and the length of the cap Therefore, it is an object of the present invention to provide a water-stopping method for an electric wire terminal splice part and a water-stopping structure formed by the method, which can reduce material costs and eliminate waste.

In order to solve the above-mentioned problems, the present invention provides a stopper plug in which one end opening of a heat-shrinkable tube having a required length is used as an insertion opening for a wire terminal splice part and a water-stopper injection hole is provided in the other end opening. Using a cap with a close fit,
First, from the insertion opening of the cap, a terminal splice portion where the core wires of the ends of a plurality of wires are welded, an electric wire provided with an insulating coating layer continuous with the core wire and the core wire exposed portion that is continuous with the terminal splice portion, Insert until the terminal splice contacts the stopcock,
Next, the heat shrinkable tube is heated to shrink,
Next, the electric wire is characterized in that a water-stopping agent is pressurized and injected into the cap from a water-stopper injection hole provided in the stopper, and the water-stopping agent is injected to a required position of the insulating coating layer of the electric wire. A waterproofing method for the terminal splice is provided.

As described above, the terminal splice part is inserted into the cap first, and after the insertion, the cap is heat-shrinked so that the inner peripheral surface of the cap is brought into close contact with the inserted outer splice part and the outer periphery of the continuous wire group. Even in the close contact state, a slight gap is generated between the inner peripheral surface of the cap and the insertion member, and there is a minute gap between the wire bundles.
In this way, after shrinking the cap, the water-stopping agent is injected under pressure from the water-stopper injection hole of the stopper attached to the cap. Therefore, it is possible to prevent overflow of the water-stopping agent generated when the heat-shrinkable tube is contracted after the water-stopping agent is injected, and it is not necessary to lengthen the cap more than necessary. Therefore, when the conventional cap length is 60 mm or more, it can be shortened to about 40 mm. Further, since the water-stopping agent is filled in the minute gap between the inner peripheral surface of the shrunk cap and the outer periphery of the terminal splice portion, the water-stopping agent does not collect in the lower portion of the terminal splice portion, and the saddle type shown in FIG. do not become.
In addition, when a water-stopping agent is injected under pressure into the gap between the core wire and the insulation coating layer of the electric wire continuous to the terminal splice part, the gap is surely formed without generating a gap due to capillary action in the gap. The water-stopping agent can be filled, and the water-stopping accuracy can be improved. In particular, the amount of water-stopping agent used can be greatly reduced and the cost can be reduced.

Before the heat shrinkable tube of the cap is heat-shrinked, if a water-stopper is filled into the cap from the water-stopper injection hole of the stopper, the water-stopper will not be pushed out of the water-stopper injection hole during the shrinkage. It is necessary to close the water-stopper injection hole.
However, in the present invention, since the cap is not filled with the water-stopping agent when the cap is contracted, there is no problem even if the water-stopper injection hole is provided in the stopper. Therefore, it is not necessary to specify the correlation between the shrinkage temperature of the heat-shrinkable tube and the height of the water-stopping liquid, and the material for the stopper and the material for the heat-shrinkable tube can be arbitrarily selected according to the function.

  Note that the water stop agent does not flow by setting the liquid amount to an optimum value even in natural standing, and it is not necessary to close the water stop agent injection hole.

  As the water-stopping agent, those having a relatively low viscosity and good permeability at room temperature are preferably used. For example, an epoxy resin having a viscosity of less than 2000 mPa · s is preferably used. The water-stopping agent may have a relatively low viscosity in addition to the epoxy resin material such as room temperature curing, heat curing, and photocuring.

  Although it is preferable to provide one water-stopper injection hole provided in the stopcock at the center of the stopcock, it is not limited. It is preferable that the size of the water-stopper injection hole is as small as possible, specifically, a small diameter of 0.5 mm or less.

  It is preferable to provide an injection facility for inserting the discharge portion of the nozzle into the water-stopping agent injection hole having a small diameter as described above and pushing out the water-stopping agent from the nozzle at a required pressure.

  Moreover, this invention provides the waterproof structure of the electric wire terminal splice part stopped by the said method.

  As described above, according to the present invention, the opening of the cap formed of the heat-shrinkable tube is closed with a stopper provided with a water-stopping agent injection hole, and the water-stopping agent is not put in the cap, Precede the terminal splice. Furthermore, before injecting the water-stopping agent, the cap is heated and thermally contracted, and the gap between the inner peripheral surface of the cap and the inserted terminal splice is made minute. In this state, by pressing the water-stopping agent under pressure from the water-stopper injection hole of the stopcock, it is only necessary to inject the minimum amount of water-stopping agent into the cap. And the length of the cap need not be longer than necessary. Note that the water stop agent does not flow by setting the amount of the liquid optimally even in natural standing, it is not necessary to close the water stop agent injection hole, and the outflow of the water stop agent can be reliably prevented.

1 shows an embodiment of the present invention, (A) is a cross-sectional view showing a water-stop structure of a wire terminal splice part, (B) is a cross-sectional view taken along line BB of (A), and (C) is a cross-sectional view of C- of (A). FIG. It is drawing which shows the terminal splice part of an electric wire group. (A)-(E) are drawings which show the process of the water stop method. It is sectional drawing of a prior art example. It is sectional drawing which shows the trouble of a prior art example.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a waterproof structure of an electric wire terminal splice formed by the waterproof method of the present invention, and FIG. 3 shows the steps of the waterproof method.

  As shown in FIG. 1, a cap 3 is provided with one end opening of the heat shrinkable tube 1 as an insertion port of a splice part and a stopper plug 2 fitted and fixed to the other end. In a cap 3 in which the heat-shrinkable tube 1 is heated and shrunk, a wire terminal splice portion 6 (hereinafter abbreviated as a splice portion 6) of a number of electric wires 5, a core wire 7 continuous with the splice portion 6, and a core wire 7 are continuous. An electric wire portion having an insulating coating layer to be inserted is inserted, and a gap between the outer periphery of the inserted material and the inner peripheral surface of the cap 3, a gap between the core wires 7, and a gap between the electric wires is filled with a water-stopping agent 10, 10 is cured.

  As shown in FIG. 2, the splice portion 6 peels off the insulating coating layer 8 at the end of the electric wire 5 to expose the core wire 7, and the core wire 7 is laminated and resistance welding or ultrasonic welding is performed to form a rectangular block. It is what. The core wire 7 of each electric wire 5 branches and continues from the splice portion 6, and the electric wire 5 from which the insulating coating layer 8 is not peeled off is inserted into the cap 3 in the cap 3 in a required shape. .

  In this embodiment, the filling amount of the waterproofing agent 10 can be reduced by managing the filling amount of the waterproofing agent 10 by height. Further, the length of the heat shrinkable tube of the cap 3 is set to 70 to 50% of the length of the cap shown in FIG. Specifically, the length of FIG. 4 is 60 mm or more, and in this embodiment, it is 40 mm.

A method of forming the waterproof structure of the splice part shown in FIG. 1 will be described with reference to FIG.
As shown in FIG. 3A, the heat-shrinkable tube 1 is cut to a required length, and one end opening is used as an insertion port 1a for the splice part. A stopper plug 2 made of a thermoplastic resin provided in the center of the other end opening 1b with a water-stopper injection hole 2a penetrating in the center is disposed. In this state, the heat-shrinkable tube 1 on the outer periphery of the stopper plug 2 is heated. A cap 3 is prepared which is shrunk and has a stopper plug 2 fitted and fixed.

In the present embodiment, the stopper 2 is formed of a thermoplastic polyolefin resin, and the base of the heat shrinkable tube 1 is made of polyolefin resin, so that the stopper 2 is fitted and fixed to the other end opening 1 b of the heat shrinkable tube 1. In this state, they are easy to stick to each other.
The inner diameter of the water-stopping agent injection hole 2a provided at the center of the stopper plug 2 is 0.5 mm or less, and in this embodiment, it is 0.5 mm.

  In the state where the heat shrinkable tube 1 is not heated and shrunk, as shown in FIG. 3B, first, the splice portion 6, the core wire 7 continuous to the splice portion 6, and the required length continuous to the core wire exposed portion. The electric wire 5 is inserted from the insertion port 1a, and the splice portion 6 at the distal end on the insertion side is brought into contact with the stopper 2 on the bottom side to stop the insertion. At this time, since the cap 3 is not contracted, it can be easily inserted.

  Next, as shown in FIG. 3C, the heat shrinkable tube 1 is heated to a shrinkage temperature (for example, 110 ° C. to 150 ° C.). By this heating, the heat shrinkable tube 1 is shrunk, and its inner peripheral surface is shrunk into a state where a slight gap is formed between the splice portion 6, the bundled core wire 7, and the plurality of electric wires 5. And it shrink | contracts so that it may closely_contact | adhere to the outer peripheral surface of the stopper plug 2, and the adhering strength with the stopper plug 2 increases.

  Next, as shown in FIG. 3 (D), a nozzle 15 for discharging a water-stopping agent is inserted into the water-stopping agent injection hole 2 a of the stopper 2, and the water-stopping agent 10 is inserted into the cap 3 from the nozzle 15 at the bottom side. Pressure injection toward the insertion port 1a side. In the present embodiment, a low viscosity 2000 mPa · s epoxy resin having a good fluidity before curing is used as the water stop agent 10.

Since the gaps between the inner peripheral surface of the heat shrinkable tube 1 and the outer periphery of the splice portion 6, the core wire portion, and the wire bundle portion are very narrow, the water-stopping agent 10 to be injected is bundled in approximately half of the conventional injection amount. It reaches the part of the electric wire 5 that became. In addition, the gap is narrow and the water-stopping agent 10 is injected under pressure from the nozzle 15 so that the gap is filled, and the gap can be reliably filled without generating a gap.
In addition, when the heat shrinkable tube 1 is transparent or translucent, the height of the water-stopping agent 10 filled in the heat shrinkable tube 1 can be checked, and the position (from the insertion port 1a) reaches about 30 mm from the bottom surface. Inject to 10mm position) and stop. Thus, since it can be filled while checking, the water-stopping agent 10 does not overflow from the insertion port 1a.

  After injecting the water-stopping agent 10 into the cap 3 as described above, as shown in FIG.

  Through the above-described steps, a waterproof structure in which the splice portion 6 shown in FIG. 1 is embedded in the water-stopping agent 10 cured in the cap 3 can be formed. When the waterproof structure is adopted, the length of the cap 3 is not excessively long, and the water-stopping agent 10 injected into the cap 3 can be reduced, and the cost can be reduced. Furthermore, since the water-stopping agent 10 does not collect in the lower part of the cap 3, it does not become a saddle after curing, and the occurrence of defective products can be reduced.

  As described above, the water-stopping agent 10 is injected into the water-stopping agent injection hole 2 a of the stopcock 2 by inserting the nozzle 15 into the water-stopping agent injection hole 2 a and pressurizing the water-stopping agent 10. Any injection means may be used as long as the injection method can be adopted.

DESCRIPTION OF SYMBOLS 1 Heat-shrinkable tube 2 Stopper 2a Water-stop agent injection hole 3 Cap 5 Electric wire 6 Splice part 7 Core wire 10 Water-stop agent 15 Nozzle

Claims (2)

While using one end opening of the heat-shrinkable tube with the required length as the insertion port of the electric wire end splice part, using a cap tightly fitted and fixed to a stopper plug provided through the water-stopping agent injection hole in the other end opening,
First, from the insertion opening of the cap, a terminal splice portion where the core wires of the ends of a plurality of wires are welded, an electric wire provided with an insulating coating layer continuous with the core wire and the core wire exposed portion that is continuous with the terminal splice portion, Insert until the terminal splice contacts the stopcock,
Next, the heat shrinkable tube is heated to shrink,
Subsequently, the molten water-stopping agent is injected into the cap under pressure from the water-stopper injection hole provided in the stopper, and the water-stopping agent is injected to a required position of the insulating coating layer of the electric wire. How to waterproof the wire terminal splice.   The waterproof structure of the electric wire terminal splice part formed by the method of Claim 1.

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