JP2011065924A - Forming method for water cut-off section of shield wire, and shield wire having water cut-off section - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water cut-off section which is excellent on water cut-off performance of a shield wire and hardly enlarges an outer diameter of the shield wire. <P>SOLUTION: In a forming method for a water cut-off section of a shield wire wherein a plurality of core wires are covered with a shield layer and the shield layer is covered with a sheath of an insulating layer, the plurality of core wires are exposed by cutting and removing the shield layer and the sheath at a terminal of the shield wire, the exposed core wires are respectively passed through hot melt tubes, and inserted ends of respective hot melt tubes are located at a cut position of the sheath. Then, upon holding the cut position of the sheath, half-lapped winding of an adhesive tape is continuously applied from an outer peripheral surface of the sheath at a remained side to an outer periphery of the hot melt tubes, and the tip of the exposed core wires is vertically retained as an upper end. Then, the hot melt tubes are melted inside the adhesive tape by heating the half-lapped winding section of the adhesive tape, and the melted hot melt is penetrated into gaps inside the sheath from the cut position of the sheath in order to prepare the water cut-off section inside the sheath. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

   The present invention relates to a method for forming a water-stop portion of a shielded electric wire and a shielded electric wire having a water-stop portion formed by the method. The water stop part which interrupts | blocks that the water which penetrate | invaded in the shield electric wire in a flooded area | region is transmitted to the terminal side of a non-flooded area | region is provided.

  Among electric wires arranged in an automobile, shielded electric wires are used particularly in an arrangement region where shielding against noise is required. As shown in FIG. 5 (A), a shielded electric wire 100 is formed by covering a core wire 102 made of a plurality of insulated covered electric wires and a grounding drain wire 103 with a shield layer 104 made of a metal foil or a metal mesh tube, The shield layer 104 is covered with a sheath 105 made of an outer layer of an insulating resin layer (see Japanese Patent Application Laid-Open No. 2002-208321).

As shown in FIG. 5 (B), the shielded electric wire 100 is normally connected to both terminals with terminal fittings 107 and 108, and these terminal fittings 107 and 108 are inserted into connectors 109A and 109B. It fits into the connector housing, or is fitted and connected to a connector of another electric wire end.
At both ends of the shielded electric wire 100, the sheath 105 and the shield layer 104 are peeled over about 80 to 200 mm, and the exposed end of the core wire 102 is further peeled to crimp the terminal fittings 107 and 108. .

In the shielded electric wire 100, there are voids between the core wires 102, between the core wires 102 and the shield layer 104, and between the shield layer 104 and the sheath 105. Therefore, when the terminal to which the terminal fitting of the shielded electric wire 100 is connected is located in the flooded area, a waterproof measure is taken such that the connector connected to the terminal fitting is a waterproof connector.
However, there is a possibility that water is transmitted to the inside of the shielded electric wire 100 through the gap opened at the peeled end on the flooded region side, and the water is generated on the terminal side connected to the other end of the shielded electric wire 100. When the other end of the shielded electric wire 100 is wired in the non-water-immersed region, the terminal of the terminal is inserted into the non-waterproof connector, so that the water from the water-immersed region side of the shielded wire 1 reaches the terminal on the non-water-immersed region side. It is necessary to stop the water before.

  6A and 6B, as a countermeasure against water stoppage of the shielded electric wire, a water-stopping agent 120 made of silicone is injected at the peeling position P of the shielded electric wire 100, and the water stoppage of the shielded electric wire 100 is stopped. In some cases, the water stop portion 122 is provided by filling the agent 120 and then winding the butyl pad 121 having a water stop function around the outer periphery of the core wire 102 exposed from the outer periphery of the sheath 105 with the peeling position P interposed therebetween. Many. The thickness of the butyl pad 121 is about 1.5 mm to 3 mm.

In Japanese Patent Application Laid-Open No. 2008-67545 (Patent Document 2), a hot melt tube is sheathed on a drain line exposed to a core wire by cutting and removing the sheath of the drain wire brought into contact with the shield layer of the shielded wire. At the same time, a heat shrink tube is further sheathed on the hot melt tube, and the heat shrink tube is heated to melt the hot melt tube and shrink the heat shrink tube to adhere to the drain wire to prevent the drain wire from water stopping. I am trying.
In Patent Document 2, when a terminal connected to the terminal of the drain wire is inserted and connected to the connector, the drain wire is stopped to prevent water from entering the connector through the drain wire.

JP 2002-208321 A JP 2008-67545 A

In the case where the water stop portion 122 shown in FIG. 6 is provided, since the butyl pad 121 is thick, the outer diameter of the water stop portion 122 is enlarged, and a wire harness in which a sensor system circuit having a large number of shielded electric wires 100 overlaps is used. There is a problem that the wire harness cannot be accommodated in the corrugated tube of the exterior material.
Moreover, if the water stop agent is cured at the cutting position of the sheath 105 of the shielded electric wire 100 to form the water stop portion, the water stop portion may be destroyed by thermal shock or vehicle vibration. In particular, due to the difference in thermal contraction rate between the sheath 105 and the core wire 102, there is a possibility that the water stop portion is displaced. This deviation increases due to the thermal shock and vehicle vibration, and there is a possibility that the water stoppage cannot be maintained.

In addition, when the exposed drain wire of Patent Document 2 is covered with a hot melt tube and a heat-shrinkable tube and heated, the melted hot melt is extruded from the heat-shrinkable tube when the heat-shrinkable tube is shrunk, and heat shrinks. Hot melt tends to protrude from the outside of the tube. This protruding hot melt may adhere to other parts and cause contact failure. In addition, since there is a hot melt film on the inner peripheral surface of the heat shrinkable tube, the heat shrinkable tube may be difficult to slide when the heat shrinkable tube shrinks.
As described above, the water stopping method in which the drain line exposed by peeling the sheath is combined with the hot melt tube and the heat shrinkable tube and is heated at the heat shrinkage temperature has the above-described problems.

  The present invention has been made in view of the above problems, and when forming a water-stop part using a hot melt tube, the protrusion of the melted hot-melt tube to the outside is eliminated, and An object is to suppress the enlargement of the water stop portion that occurs when a butyl pad is wound, and to improve the water stop performance so that the water stop portion is not destroyed by thermal shock or vehicle vibration.

In order to solve the above problems, the present invention is a method for forming a water stop portion of a shielded wire in which a plurality of core wires are covered with a shield layer, and the shield layer is covered with a sheath of an insulating resin layer,
At the end of the shielded wire, the shield layer and the sheath are cut and removed to expose the plurality of core wires,
Next, each exposed core wire is passed through a hot melt tube, the insertion end of each hot melt tube is positioned at the cutting position of the sheath,
Next, sandwiching the cutting position of the sheath, the adhesive tape is continuously half-wrapped from the outer peripheral surface of the remaining sheath to the outer periphery of the hot melt tube,
Next, hold the exposed core wire in the vertical direction with the tip of the core wire as the upper end,
Next, the half-wrap winding portion of the adhesive tape is heated to melt the hot melt tube inside the adhesive tape, and the molten hot melt flows down from the cutting position of the sheath to the void inside the sheath and penetrates. And providing a method for forming a water stop portion of a shielded electric wire having a water stop portion provided inside the sheath.

  In the present invention, the core wire exposed by cutting and removing the sheath is passed through each hot melt tube, the hot melt tube is brought into contact with the cut surface of the sheath, and the shielded electric wire is held vertically and heated. The hot melt is allowed to flow into the gap inside the sheath. Thus, the melted hot melt is infiltrated into the gaps between the sheath and the shield layer, the shield layer and the core wire, and the core wires inside the sheath, and then cured to form a water stop portion inside the sheath. .

After each core wire is passed through the hot melt tube, the adhesive tape is half-wrapped from the outer periphery of the sheath to the outer periphery of the hot melt tube. As the adhesive tape, a thin vinyl chloride tape having a thickness of about 0.1 mm to 0.2 mm is used. Therefore, compared with the case where a thick butyl pad is used, the thickness can be reduced to about 1/10 and the finished outer diameter can be reduced by about 30%.
The reason why this adhesive tape is half-wrapped is that when the hot melt tube is melted by heating with a heater or the like from the outside, the melted hot melt is stored inside the wound adhesive tape. The hot melt functions as a receiving portion that gradually flows into the sheath. Moreover, in the heat shrinkable tube of Patent Document 2, the hot melt inside protrudes because it shrinks when heated, but the adhesive tape does not shrink even when heated, so that the melted and accumulated hot melt protrudes and adheres to the outside. Can be prevented.

In this invention, the water stop part is provided in the inside of a sheath, and it differs from the structure which forms the water stop part in the outer periphery of the core wire exposed from the cut end surface of the sheath of the prior art example.
Thus, in the present invention, there is no water stop portion on the core wire side exposed by peeling the sheath, and hot melt is applied to the gap between the sheath, the shield layer, and the core wire on the inner side of the sheath of the shielded electric wire. It is infiltrated and cured to provide a water stop, and the water stop is not exposed on the outer surface.
Therefore, even if cracks enter the cured water sealant due to the difference in shrinkage between the core wire and sheath in the thermal shock, it prevents the cured water sealant from peeling off and degrading the water stop performance. can do.
Further, the cost can be reduced by eliminating the need for relatively expensive butyl pads and heat shrinkable tubes.

The number of the core wires is 2 to 6, and the core wire is formed of a covered round electric wire in which the core wire is covered with an insulating resin layer such as vinyl chloride, and the outer diameter corresponds to the circuit to be configured. Are often equivalent.
The shield layer is formed of a metal mesh tube or metal foil tape, and provided with a drain line that is in contact with the inner surface of the shield layer. In addition, it is good also as a drain wire which pulls out the said shield layer from the sheath peeling part of a terminal, and connects it to a ground terminal as a twisted wire.

Each core wire is passed through a hot melt tube having a length of 10 to 30 mm, and an adhesive tape is wound at a length of 55 to 65 mm from the outer peripheral surface of the sheath to the outer periphery of the hot melt tube. It is preferable that the length from the end to the end of the core wire is 80 mm to 200 mm.
Thus, if it is set as about 80 mm-200 mm, a terminal metal fitting can be crimped | bonded to the terminal of each core wire, and it can be set as the dimension which can insert and lock this terminal metal fitting to a connector.

  The present invention provides a shielded electric wire having a water stop portion formed by the above method.

  The shielded electric wire of the present invention is routed in a vehicle, and the terminal side of the shielded electric wire provided with the water stop portion is routed in the vehicle interior of the non-immersed area and connected to the terminal on the opposite side of the shielded electric wire. The terminal is inserted and connected to a connector disposed in the submerged area, and water that enters the shielded electric wire from the submerged area side is blocked by the water stop portion.

As described above, in the shielded electric wire of the present invention, a water stop portion is provided inside the sheath, and hot melt is provided between the core wires within the sheath, between the core wires and the shield layer, and between the core wires and the shield layer. It can increase the permeability to water and can improve the reliability of water stoppage.
Moreover, since there is a water stop part inside the sheath, the water stop part provided inside the sheath remaining side is not displaced or destroyed by thermal shock or vehicle vibration, and the water stop performance can be improved.
Furthermore, it is not necessary to wrap a thick butyl pad that covers the water stop portion, and an increase in the outer diameter of the water stop portion can be prevented. Therefore, in a wire harness in which a large number of shielded wires are converged, the outer diameter can be prevented from being enlarged even if the water stop portion is concentrated, and can be externally covered with a corrugated tube.
In addition, since a thick butyl pad is not used, there is no enlargement of the outer diameter at the water stop.
Furthermore, since a relatively expensive butyl pad and heat shrinkable tube are not used, the cost can be reduced.

It is sectional drawing of the shielded electric wire of embodiment of this invention. It is the schematic which shows the wiring position in the vehicle of the said shield wire. It is sectional drawing which shows the part provided with the water stop part of the said shield electric wire. (A)-(E) are drawings which show the formation process of a water stop part. A prior art example is shown, (A) is sectional drawing of a shielded electric wire, (B) is the schematic which shows the wiring state of a shielded electric wire. (A) is sectional drawing of the water stop part of the conventional shield electric wire, (B) is BB sectional drawing of (A).

Hereinafter, the embodiment of the shielded electric wire provided with the water stop part of the present invention is described based on Drawing 1 thru / or Drawing 4.
As shown in FIG. 1, the shielded electric wire 1 is made of a metal foil tape or a metal net tube by concentrating 2 to 6 (six in this embodiment) core wires 2 and a drain wire 3 for grounding. The shield layer 4 is covered, and the shield layer 4 is covered with a sheath 5 made of an outer skin of an insulating resin layer. In this embodiment, the shield layer 4 is wound with a metal foil tape, and the drain wire 3 is in contact with the metal foil tape.
The core wire 2 is a covered round electric wire in which a core wire obtained by twisting a large number of copper-based wires is covered with an insulating resin layer. In the present embodiment, the six core wires 2 have the same outer diameter.

As shown in FIG. 2, in the shielded electric wire 1, terminal fittings 7 and 8 are crimped and connected to the core wire 2 at both ends in the same manner as in FIG. The shielded cable 1 is routed from the flooded area (X) of the engine room to the non-immersed area (Y) of the vehicle interior, and the terminal fitting 7 is connected to one end of the shielded cable 1 positioned in the flooded area, The waterproof connector 9A is inserted and connected. The terminal metal fitting 8 is connected to the other end of the shielded electric wire 1 positioned in the non-immersed area, and is inserted into the non-waterproof connector 9B for connection.
At both ends of the shielded electric wire 1, the sheath 5 and the shield layer 4 are cut and removed over approximately 80 to 200 mm to expose the core wire 2, and the exposed end of the core wire 2 is further peeled to remove the terminal fitting. 7 and 8 are crimped.

In the shielded electric wire 1, water entering the inside of the shielded electric wire 1 from the cut end of the sheath 5 on the submerged area (X) side flows to the non-submerged area (Y) side and is transmitted to the terminal fitting 8, and the non-waterproof connector 9B. 3 is provided on the connection side with the terminal fitting 8 in order to prevent corrosion from occurring inside.
The water stop portion 10 is provided in the sheath 5 within a range of 30 to 50 mm (about 40 mm in this embodiment) on the remaining side of the sheath 5 from the cutting position P1 of the sheath 5.
Since the water stop portion 10 is provided inside the sheath 5, naturally, a waterproof material such as a butyl pad is not wrapped around the outer periphery of the water stop portion.

The formation method of the water stop part 10 is shown in FIG.
First, on the terminal side of the non-immersed area (Y) of the shielded electric wire 1, the sheath 5 and the shield layer 4 are cut by making an annular cut at a position 110 mm from the tip P2. After cutting, the sheath 5 and the shield layer 4 are moved to the tip P2 and extracted, and the core wire 2 and the drain wire 3 are exposed as shown in FIG.

  Next, as shown in FIG. 4B, a hot melt tube 6 that is solidified into a tube shape is passed through each core wire 2 and drain wire 3 exposed from the cutting position P1 through the tip P2, and each hot melt tube 6 is passed through. The distal end of the insertion side is moved to the cutting position P1 and brought into contact with the cutting end surface of the sheath 5. Each hot melt tube 6 has a length of 10 to 30 mm, and in this embodiment, 20 mm.

  Next, as shown in FIG. 4C, the adhesive tape 11 is continuously wound by half wrap winding from the outer peripheral surface of the sheath 5 remaining across the cutting position P1 to the position where the hot melt tube 6 is covered. The adhesive tape 11 is wound over the entire length of the hot melt tube 6, the winding length on the outer peripheral surface of the sheath 5 is 30 mm, the winding length on the hot melt tube 6 side is 30 mm, and the total length of the adhesive tape 11 is 60 mm. The dimension from the tip of the adhesive tape 11 to the tip P2 of the core wire 2 exposed is 80 mm.

  Next, as shown in FIG. 4 (D), the tip P2 of the core wire 2 from which the shielded electric wire 1 is exposed is held vertically. In this state, the adhesive tape 11 wound around the outer periphery of the hot melt tube 6 is heated by the heater 12 to melt the hot melt tube 6 inside the adhesive tape 11. During this heating, the pressure-sensitive adhesive tape 11 does not shrink and plays a role of accumulating the molten hot melt 6A.

Since the shielded electric wire 1 is held vertically and the lower end of the hot melt tube 6 is in contact with the cutting position P1 of the sheath 5, the molten hot melt 6A flows down from the cut end surface of the sheath 5 into the gap C inside the sheath 5. Go.
Specifically, as shown in FIG. 4E, the gap C inside the sheath 5, that is, the gap between the core wires 2, the gap between the core wire 2 and the shield layer 4, and the gap between the shield layer 4 and the sheath 5. The molten hot melt 6A flows down and penetrates. The amount of hot melt 6A that melts and permeates corresponds to the size (volume) of all the hot melt tubes 6 that are externally fitted to the core wire 2 and the drain wire 3. In this embodiment, the hot melt 6A penetrates from the cutting position P1 of the sheath 5 to the sheath remaining side up to about 40 mm.

  As described above, the hot melt tube 6 is melted by heating with the heater 12, and after the melted hot melt 6A penetrates into the gap C in the sheath 5, the heating by the heater 12 is stopped and held for a required time. The hot melt 6 </ b> A is cured to form the water stop portion 10 inside the sheath 5. Thus, since the water stop part 10 is provided in the inside of the sheath 5 and the water stop part 10 is covered with the sheath 5, the butyl pad and the heat shrinkable tube used in the conventional example become unnecessary, and the water stop part 10 is covered with the butyl pad. Compared with the case, the outer diameter can be reduced by about 30%.

  Moreover, since the water stop portion 10 in which the hot melt is cured is provided inside the sheath 5 and the water stop portion 10 is not provided on the exposed side of the core wire from the cutting position P1 of the sheath 5, the influence of thermal shock and vehicle vibration is suppressed. In addition, it is possible to prevent the occurrence of cracks and displacement of the silicone that is filled and cured between the sheath 5 and the core wire 2. Therefore, the sealing property set in the durability test in the thermal shock can be ensured.

  Also, the hot melt tube is not melted in the heat shrink tube, but is melted inside the adhesive tape wound around the hot melt tube, and the adhesive tape does not shrink, so the melted hot melt protrudes to the outside and adheres to the external member. The problem can be solved. In addition, when the hot melt tube is melted, the shielded electric wire is held in the vertical direction so that the melted hot melt flows into the gap inside the sheath 5 and penetrates, so that the hot melt can be stored inside the adhesive tape. No, the hot melt can be prevented from overflowing outside.

DESCRIPTION OF SYMBOLS 1 Shield electric wire 2 Core wire 4 Shield layer 5 Sheath 6 Hot melt tube 6A Hot melt 11 Adhesive tape 12 Heater 10 Water stop part P1 Cutting position C Gap

Claims (4)

A method for forming a water stop portion of a shielded wire in which a plurality of core wires are covered with a shield layer, and the shield layer is covered with a sheath of an insulating resin layer,
At the end of the shielded wire, the shield layer and the sheath are cut and removed to expose the plurality of core wires,
Next, each exposed core wire is passed through a hot melt tube, the insertion end of each hot melt tube is positioned at the cutting position of the sheath,
Next, sandwiching the cutting position of the sheath, the adhesive tape is continuously half-wrapped from the outer peripheral surface of the remaining sheath to the outer periphery of the hot melt tube,
Next, hold the exposed core wire in the vertical direction with the tip of the core wire as the upper end,
Next, the half-wrapped portion of the adhesive tape is heated to melt the hot melt tube inside the adhesive tape, and the molten hot melt flows down from the cutting position of the sheath to the gap inside the sheath and penetrates. A method for forming a water stop portion of a shielded electric wire having a water stop portion provided inside the sheath.   Each core wire is passed through a hot melt tube having a length of 10 to 30 mm, and an adhesive tape is wound at a length of 55 to 65 mm from the outer peripheral surface of the sheath to the outer periphery of the hot melt tube. The method for forming a water stop portion of a shielded electric wire according to claim 1, wherein the length from the end to the tip of the core wire is 80 mm to 200 mm.   The shielded electric wire in which the water stop part is formed by the method of Claim 1 or Claim 2.   The terminal side of the shielded electric wire provided in the vehicle and provided with the water stop portion is arranged in the vehicle interior of the non-immersed region, and the terminal connected to the terminal on the opposite side of the shielded electric wire is arranged in the submerged region. The shielded electric wire according to claim 3, wherein water that is inserted into and connected to the connector and enters the shielded electric wire from the flooded area side is blocked by the water stop portion.

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