JP2018170093A - Wire with cap - Google Patents

Abstract

A technique for suppressing an exposed core portion from breaking through a heat shrinkable cap when the heat shrinkable cap shrinks is provided. An electric wire with a cap includes an electric wire having a covering portion covered with a core wire, an exposed core wire portion located on one end side of the covering portion and exposing the core wire, and one end portion closed and the other end. A cap body portion formed in a closed tubular shape with an opening, and an adhesive containing a thermoplastic resin provided on the inner surface of the cap body portion, and covered from the exposed core portion side to the electric wire A heat shrink cap. Moreover, in this electric wire with a cap, in the state where the heat-shrinkable cap is heat-shrinked, the radial thickness of the cap body portion in the portion surrounding the tip portion of the exposed core portion from the outer periphery is the cap body in the portion surrounding the covering portion from the outer periphery. It is larger than the radial thickness of the part. [Selection] Figure 3

Description

  The present invention relates to a technique for shrinking a heat shrink cap after inserting an electric wire into the heat shrink cap.

  In Patent Document 1, a hot-melt adhesive is provided on the inner wall of a heat-shrinkable tube, and one end is first heat-shrinked and sealed to form a heat-shrinkable cap. The technique which heat-shrinks the remaining part of a cap and seals the exposed core part of an electric wire is disclosed.

  Patent Document 2 discloses a technique for inserting an electric wire or the like into a cover member formed in a closed tubular shape having one end closed and the other end open. Moreover, in patent document 2, the said one end part by which front-end | tip parts, such as an electric wire, are abutted among the cover members is formed thicker than another part. Therefore, it is suppressed that an electric wire etc. breaks through a cover member in the case of abutment.

Japanese Patent Laid-Open No. 11-178142 JP 2013-89439 A

  When the heat-shrinkable cap is heated, the heat-shrinkable cap is shrunk mainly in the radial direction, and the inner surface of the heat-shrinkable cap and the outer surface of the covering portion of the electric wire and the exposed core portion are in close contact. In the case of heat shrinkage, if there is a rounded portion on the exposed core portion, the rounded portion may be strongly pressed against the heat shrink cap, and the heat shrink cap may be broken through.

  However, the cited document 1 does not disclose a technique for suppressing the breakage of the cap, and the cited document 2 does not disclose a technique for thermally shrinking the cap. Therefore, even if the techniques described in these documents are used, it is difficult to suppress the breakage of the cap due to the heat shrinkage.

  Then, an object of this invention is to provide the technique which suppresses that an exposed core part pierces a heat contraction cap when a heat contraction cap contracts.

  In order to solve the above-mentioned problem, an electric wire with a cap according to a first aspect is an electric wire having a covering portion covered with a core wire, and an exposed core wire portion located on one end side of the covering portion and exposing the core wire. And a cap main body portion formed in a closed tubular shape having one end closed and the other end open, and an adhesive containing a thermoplastic resin provided on the inner surface of the cap main body, A heat shrink cap that covers the electric wire from the exposed core portion side, and the cap main body in a portion that surrounds the distal end portion of the exposed core portion from the outer periphery in a state where the heat shrink cap is thermally contracted The radial thickness of the portion is larger than the radial thickness of the cap body portion in the portion surrounding the covering portion from the outer periphery.

  The electric wire with a cap according to the second aspect is an electric wire with a cap according to the first aspect, and the electric wire has a core wire mainly including aluminum.

  The electric wire with a cap according to the third aspect is an electric wire with a cap according to the first or second aspect, and the electric wire has a plurality of core wires made of different kinds of metals.

  The electric wire with a cap according to the fourth aspect is an electric wire with a cap according to any one of the first to third aspects, and the cap main body part includes a cylindrical outer part having both ends opened, and the outer part. A plug portion that closes an opening at one end of the portion.

  According to the first to fourth aspects, in the state where the heat-shrinkable cap is heat-shrinked, the radial thickness of the cap body portion in the portion surrounding the distal end side of the exposed core portion from the outer periphery is the portion surrounding the covering portion from the outer periphery. It is larger than the thickness of the cap body. By using the cap main body having such a thickness, the exposed core portion is prevented from breaking through the heat shrink cap when the heat shrink cap shrinks.

  According to the second aspect, the core wire mainly including aluminum is likely to be deformed into an unintended shape in the process of manufacturing the exposed core wire portion, and an angular portion is likely to be formed in the exposed core wire portion. Even in this case, by using the cap main body portion having the above-described thickness, the exposed core portion is prevented from breaking through the heat shrink cap when the heat shrink cap shrinks.

  According to the 3rd aspect, the some core wire comprised with a different kind of metal tends to deform | transform into an irregular shape in the process of manufacturing an exposed core wire part, and it is easy to produce the angled part in an exposed core wire part. Even in this case, by using the cap main body portion having the above-described thickness, the exposed core portion is prevented from breaking through the heat shrink cap when the heat shrink cap shrinks.

  According to the fourth aspect, by using the cap body portion having the cylindrical exterior portion opened at both ends and the plug portion closing the opening at one end of the exterior portion, when the heat shrink cap is contracted, the exposed core portion is Breaking through the heat shrink cap is suppressed.

It is a schematic sectional drawing which shows a heat contraction cap. It is a schematic sectional drawing which shows a mode that the heat contraction cap was covered with respect to the electric wire. It is a schematic sectional drawing which shows an electric wire with a cap. It is a schematic sectional drawing which shows an electric wire with a cap.

{Embodiment}
Hereinafter, the electric wire with a cap concerning an embodiment is explained. FIG. 1 is a schematic cross-sectional view showing a heat shrink cap 10. FIG. 2 is a schematic cross-sectional view showing a state in which the heat shrink cap 10 is put on the electric wire 40.

  The heat-shrinkable cap 10 includes a cap main body 20 and an adhesive 30 that is provided on the inner surface of the cap main body 20 and includes a thermoplastic resin.

  The cap main body 20 is formed in a closed tubular shape in which one end 21 is closed and the other end 22 is open. Moreover, after covering the electric wire 40, the cap main-body part 20 can heat-shrink at least the other end part 22 at least. Specifically, here, the cap main body portion 20 includes an exterior portion 23 and a plug portion 28.

  The exterior portion 23 includes a first portion 24 and a second portion 25 connected to the first portion 24 from the one end portion 21 toward the other end portion 22 using a heat shrinkable tube having both ends opened as a material.

  The first portion 24 is a portion formed with a greater radial thickness than the second portion 25. The first portion 24 has a small diameter portion 240 and a large diameter portion 241 connected to the small diameter portion 240 from the one end portion 21 toward the other end portion 22 using a heat shrinkable tube having both ends opened as a material.

  At least the large-diameter portion 241 and the second portion 25 of the first portion 24 of the exterior portion 23 are in a state capable of being thermally contracted after being covered with the electric wire 40. That is, the large-diameter portion 241 and the second portion 25 of the first portion 24 are in a state capable of being thermally contracted in a state where the heat-shrinkable cap 10 is present alone.

  Here, the exterior part 23 is formed using a heat-shrinkable tube having both ends opened as a material. Such a heat-shrinkable tube is obtained by, for example, injection molding, and is expanded in diameter after the crosslinking treatment to impart heat-shrinkability. Further, in the heat shrinkable tube, a thickness in the radial direction is formed large at a portion on one end side (portion corresponding to the first portion 24), and a radial direction is formed on a portion on the other end side (portion corresponding to the second portion 25). Is formed with a small thickness. At this point, the adhesive layer is not provided on the inner surface of the heat-shrinkable tube. And the following processes are given with respect to this heat contraction tube, and the heat contraction cap 10 is manufactured.

  The exterior portion 23 is formed by thermally shrinking the one end portion 21 of the heat shrinkable tube so as to have a smaller diameter than the other end portion 22 to form the small diameter portion 240. For example, the exterior part 23 can be formed by heat-shrinking only the one end part 21 of the heat-shrinkable tube. In the following, an embodiment in which the small diameter portion 240 is formed so that the heat shrinkage is completely completed and is not further heat shrunk will be described. Good.

  The large-diameter portion 241 includes a first large-diameter portion 242 that continues to the small-diameter portion 240 and gradually increases in diameter, and a second large-diameter portion 243 that continues to the first large-diameter portion 242 and is uniform in the axial direction. The first large-diameter portion 242 is a portion that is not contracted as much as the small-diameter portion 240, but is a portion that has been thermally contracted due to the transfer of heat when the small-diameter portion 240 is thermally contracted.

  However, it is not essential to form the exterior portion 23 by thermally shrinking the one end portion 21 of the heat shrinkable tube to form the small diameter portion 240. For example, when manufacturing the heat-shrinkable tube by expanding the diameter of the tube material, the exterior portion 23 is expanded so that the other end portion 22 side has a larger diameter than the one end portion 21 side. And a large diameter portion 241 may be formed.

  The second portion 25 is a portion that continues to the second large diameter portion 243 of the first portion 24. Specifically, the inner diameter of the second portion 25 and the inner diameter of the second large diameter portion 243 are substantially the same, and the inner surfaces of both portions are flush. On the other hand, since the thickness of the first portion 24 is larger in the radial direction than the second portion 25, the outer diameter of the second large-diameter portion 243 is larger than the outer diameter of the second portion 25, and the outer surfaces of both portions. Is stepped.

  The plug portion 28 is a portion that is provided on the inner surface of the small diameter portion 240 and closes the opening of the one end portion 21 of the exterior portion 23. The material of the plug portion 28 can be selected as appropriate. Here, a case where the plug portion 28 is formed of the same material as the adhesive 30 will be described. Here, the plug portion 28 is also provided when the adhesive 30 is provided on the cap body portion 20.

  The adhesive 30 is a member that flows and fills the gaps in the heat shrink cap 10 by heating to heat shrink the heat shrink cap 10. For this reason, the adhesive 30 is comprised with the material (for example, hot-melt-adhesive) containing a thermoplastic resin.

  Here, the adhesive 30 will be described as being retrofitted to the exterior portion 23 having the small diameter portion 240 by heat shrinking one end portion 21 of the heat shrinkable tube together with the plug portion 28. For example, by applying a hot melt adhesive in a heated and softened state to the inner surface of the exterior portion 23, the adhesive 30 and the plug portion 28 are formed, and the heat shrinkable cap 10 is obtained.

  The heat shrink cap 10 thus obtained is put on the electric wire 40. In the example shown in FIG. 2, a plurality of covered electric wires 42 are assumed as the electric wires 40. Each covered electric wire 42 includes a covered portion 46 covered with the core wire 43 and an exposed core wire portion 44 that is located on one end side of the covered portion 46 and from which the core wire 43 is exposed.

  The core wire 43 is formed of a conductive material such as copper, copper alloy, aluminum, or aluminum alloy. The core wire 43 is composed of one or more strands. When there are a plurality of covered electric wires 42, the types of the core wires 43 of the respective covered electric wires 42 may be the same or different.

  Here, as the covered electric wire 42, there are two copper electric wires 42a in which the core wire 43a is formed of copper and a copper alloy, and one aluminum electric wire 42b in which the core wire 43b is formed of aluminum and an aluminum alloy. explain. In the following description, when the core wire 43a and the core wire 43b are not distinguished from each other, they are simply expressed as the core wire 43, and when the copper wire 42a and the aluminum wire 42b are not distinguished from each other, they are simply expressed as the covered wire 42. Similarly, for the distal end portion of each core wire 43, when the distal end portion 430 a of the core wire 43 a and the distal end portion 430 b of the core wire 43 b are not distinguished, these are simply expressed as the distal end portion 430.

  The covering portion 46 is formed by extruding an insulating material such as resin around the core wire 43. An end portion of each covered electric wire 42 is an exposed core wire portion 44 where the covering portion 46 is peeled off and the core wire 43 is exposed. At least a part of the exposed core wire portion 44 is formed with a joint portion 45 in which the core wires 43 are joined together. Here, the core wires 43 are joined together by resistance welding. The core wires 43 may be joined together by welding other than resistance welding, such as ultrasonic welding, terminal crimping, or soldering. The end portion 430 of the exposed core wire portion 44 thus joined becomes an angular portion, which causes the heat shrink cap 10 to break through as described later.

  Moreover, when the electric wire 40 has the several core wire 43 comprised with a different kind of metal, the shape where each core wire 43 is irregular in the process of manufacturing the exposed core wire part 44 by the difference in those physical properties (for example, elongation rate). It is easy to deform. For example, in the present embodiment, as shown in FIG. 2, the elongation rate of the core wire 43 b mainly including aluminum is larger than the elongation rate of the two core wires 43 a mainly including copper. Further, the tip end portion 430b of the core wire 43b protrudes in a direction deviating radially outward from the tip end portions 430a of the two core wires 43a. As a result, the tip portion 430b is a particularly angular portion in the exposed core portion 44.

  Moreover, when the electric wire 40 has the core wire 43b comprised mainly including aluminum, it originates in the soft physical property of aluminum, and the core wire 43b tends to deform | transform into the shape which is not intended in the process of manufacturing the exposed core wire part 44. FIG. For example, in the present embodiment, due to the fact that the core wire 43b is configured to mainly contain aluminum, as shown in FIG. 2, the tip portion 430b of the core wire 43b is changed from the tip portion 430a of the two core wires 43a. It protrudes in a direction deviating outward in the radial direction. As a result, the tip portion 430b is a particularly angular portion in the exposed core portion 44.

  When the heat shrink cap 10 is put on the electric wire 40 from the exposed core wire portion 44 side, the tip portion 430 of the exposed core wire portion 44 is brought into contact with the plug portion 28 in the heat shrink cap 10, and the electric wire 40 extends in the extending direction. It is positioned with respect to the heat-shrink cap 10 (vertical direction in the figure). Hereinafter, this state is referred to as a wearing state. As an aspect different from the present embodiment, the electric wire 40 may be positioned with respect to the heat shrink cap 10 in a state where the tip of the joint portion 45 is not in contact with the plug portion 28 in the heat shrink cap 10.

  In the mounted state, the electric wire 40 is positioned in such a way that the tip end portion 430 of the exposed core wire portion 44 abuts against the plug portion 28 in the heat shrinkable cap 10 in the extending direction, and is perpendicular to the extending direction. Is positioned by being supported by the inner wall of the heat shrink cap 10. In the mounted state, at least one of the heat shrink cap 10 and the electric wire 40 may be held by a jig or the like (not shown).

  When the heat shrink cap 10 and the electric wire 40 are positioned, a heating step of heating the heat shrink cap 10 by the heating mechanism 80 is executed. Thereby, the large diameter portion 241 and the second portion 25 of the first portion 24 of the heat shrink cap 10 are contracted mainly in the radial direction, and the adhesive 30 flows. Then, the periphery of the exposed core wire portion 44 and the covering portion 46 is filled with the fluidized adhesive 30. As a result, the inner surface of the heat shrink cap 10 and the outer surface of the covering portion 46 of the electric wire 40 and the exposed core wire portion 44 are in close contact with each other via the adhesive 30.

  After the heat shrink cap 10 is sufficiently shrunk by this heating step, the fluidized adhesive 30 is solidified by cooling the heat shrink cap 10 to complete the capped electric wire 1. FIG. 3 is a schematic cross-sectional view showing the capped electric wire 1. The capped electric wire 1 includes an electric wire 40 and a heat shrinkable cap 10 that covers the electric wire 40 from the exposed core portion 44 side.

  As shown in FIG. 3, the exterior portion 23 after the heating step includes a first portion 26, a second portion 27, and a groove portion 29 located between the first portion 26 and the second portion 27.

  The first portion 26 is a portion formed by deforming the first portion 24 by heat shrinkage. Specifically, the first portion 26 is a portion formed by heat shrinking the large diameter portion 241 so as to be substantially the same as the diameter size of the small diameter portion 240, and has a larger radial thickness than the second portion 27. It becomes a thick cylindrical shape. The inner surface of the first portion 26 is in close contact with the outer surface of the exposed core portion 44 of the electric wire 40 through the adhesive 30.

  The second portion 27 is a portion formed by deforming the second portion 25 by heat shrinkage. Specifically, the second portion 27 is a portion formed by heat shrinking the second portion 25 so as to be substantially the same as the outer diameter of the first portion 26, and has a cylindrical shape having a larger inner diameter than the first portion 26. It becomes. The inner surface of the second portion 27 is in close contact with the outer surface of the covering portion 46 of the electric wire 40 through the adhesive 30.

  Further, the groove portion 29 gradually decreases in thickness from a portion having a large radial thickness located on the first portion 26 side toward a portion having a small radial thickness located on the second portion 27 side. Part.

  Moreover, the 1st part 26 is a part located in the one end part 21 side among the exterior parts 23 after a heating process, and is a part which surrounds the front-end | tip part 430 of the exposed core part 44 from outer periphery. The 2nd part 27 is a part located in the other end part 22 side among the exterior parts 23 after a heating process, and is a part which surrounds the coating | coated part 46 from outer periphery.

  Because of this arrangement, the tip portion 430 (particularly, the tip portion 430b protruding outward from the radial center side) is a radial direction in the heating step during the heating step. As shown in FIG. 3, the front end portion 430 b is pierced into the first portion 26.

  However, since the radial thickness of the first portion 26 is larger than the radial thickness of the second portion 27 in the cap body portion 20, the distal end portion 430 b hardly reaches the outer surface of the first portion 26. . As a result, the exposed core portion 44 is prevented from breaking through the heat shrink cap 10 when the heat shrink cap 10 shrinks.

  In this embodiment, the 1st part 26 which is a location with a high risk of breaking through surrounding the front-end | tip part 430b from the outer periphery among the exterior parts 23 is a structure with large thickness, and it breaks through by enclosing the coating | coated part 46 from outer periphery. The second portion 27, which is a portion with a low risk, has a smaller thickness than the first portion 26. Therefore, it is possible to improve the water stoppage of the electric wire 1 with a cap while suppressing the amount of the raw material of the heat-shrinkable tube to a small amount.

{Modification}
Below, the modification of the said embodiment is demonstrated. In addition, about the common point with each part in the said embodiment, the same code | symbol is attached | subjected and repeated description is avoided.

  First, with reference to FIG. 4, the modification about an electric wire with a cap is demonstrated. FIG. 4 is a schematic cross-sectional view showing the cap-attached electric wire 1A.

  In the modification shown in FIG. 4, the cap main body portion 20 </ b> A after heating the heat-shrinkable cap 10 </ b> A has a first portion 26 </ b> A, a second portion 27, and a groove positioned between the first portion 26 </ b> A and the second portion 27. And a portion 29. Here, the first portion 26A includes a cylindrical portion 260 corresponding to the first portion 26, and a closed end portion that is connected to an end of the cylindrical portion 260 opposite to the second portion 27 and gradually closes in diameter. 261.

  As in the above-described embodiment, it is not essential that the cap main body portion 20 includes the tubular exterior portion 23 and the plug portion 28 that closes the opening at one end of the exterior portion 23. As described above, the cap body 20A may be formed of a closed tubular member integrally including the first portion 26A, the second portion 27, and the groove portion 29.

  In this modification, the radial thickness of the cylindrical portion 260 and the axial thickness of the closed end portion 261 are substantially the same, and the axial thickness of the closed end portion 261 is the same as that of the second portion 27. Greater than radial thickness. In this way, the closed end portion 261 is configured to be thick so that the leading end portion 430 of the exposed core portion 44 abuts against the closed end portion 261 of the cap main body portion 20A before the heating step and the both are positioned. However, it is suppressed that the front-end | tip part 430 breaks through the closed end part 261.

  Hereinafter, other modifications will be described.

  Although the said embodiment demonstrated the aspect in which the electric wire 40 had the core wire 43a comprised mainly including aluminum, this is not essential. The electric wire 40 may not include the core wire 43a mainly including aluminum.

  Moreover, although the electric wire 40 demonstrated the aspect which has the some core wire 43 comprised with a different kind of metal in the said embodiment, this is not essential. The aspect which has the single or several core wire 43 with which the electric wire 40 is comprised with one type of metal may be sufficient.

  Moreover, although the said embodiment demonstrated the aspect in which the 1st part 26 was provided in a wider range than the front-end | tip part 430 along the extension direction of the electric wire 40, this is not essential. The first portion 26 only needs to be provided at least in a portion surrounding the tip portion 430 from the outer periphery. For example, the first portion 26 may be provided only in a portion surrounding the tip portion 430 from the outer periphery.

  Moreover, although the electric wire 40 was demonstrated as what is the aggregate | assembly of the some covered electric wire 42 in the said embodiment, this is not essential. For example, the electric wire 40 may be a single covered electric wire 42.

  In addition, each structure demonstrated by the said embodiment and each modification can be suitably combined unless it mutually contradicts.

  As described above, the present invention has been described in detail. However, the above description is illustrative in all aspects, and the present invention is not limited thereto. It is understood that countless variations that are not illustrated can be envisaged without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1,1A Electric wire with a cap 10, 10A Heat shrinkable cap 20, 20A Cap main-body part 21 One end part 22 Other end part 24, 26, 26A 1st part 25, 27 2nd part 28 Plug part 30 Adhesive 40 Electric wire 42a Copper electric wire 42b Aluminum wire 43, 43a, 43b Core wire 44 Exposed core wire part 46 Covering part 430, 430a, 430b Tip part

Claims (4)

An electric wire having a covering portion covered with a core wire, and an exposed core portion located on one end side of the covering portion and exposing the core wire;
A cap main body formed in a closed tubular shape with one end closed and the other end open; and an adhesive provided on an inner surface of the cap main body including a thermoplastic resin, and the electric wire Heat-shrinkable cap covered from the exposed core portion side,
With
In the state where the heat-shrinkable cap is heat-shrinked, the radial thickness of the cap main body portion in the portion surrounding the tip portion of the exposed core portion from the outer periphery is the diameter of the cap main body portion in the portion surrounding the covering portion from the outer periphery. Wire with a cap that is larger than the thickness in the direction. The electric wire with a cap according to claim 1,
The said electric wire is an electric wire with a cap which has a core wire comprised mainly including aluminum. The electric wire with a cap according to claim 1 or 2,
The said electric wire is an electric wire with a cap which has several core wires comprised with a different kind of metal. The electric wire with a cap according to any one of claims 1 to 3,
The said cap main-body part is an electric wire with a cap which has the cylindrical exterior part which both ends opened, and the plug part which plugs up the opening of the end of the said exterior part.

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