JP2010056020A - Covered cable and electric cable with terminal fitting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a covered cable in which reduction of current capacity can be suppressed as much as possible even if the core wire is fractured. <P>SOLUTION: The aluminum cable 10 is constructed of a core wire 11 consisting of a multi-layer linear object 17 formed in a linear line of multi-layers by winding in piles a sheet of aluminum foil 15 from one side fringe 15A and an insulating cover 12 covering its surrounding. A wire barrel 25 is crimped to the terminal of the core wire 11 and a female terminal fitting 20 is connected to it. Even if the outer circumference part of the core wire 11 is fractured accompanying crimping of the wire barrel 25, only a part of the length region along the circumference direction of the outer layer portion of the multi-layer linear object 17 is fractured. Even if an oxide film is generated on the surface of each layer and each layers are insulated in diameter direction, since a sheet of aluminum foil 15 is wound in piles, each layer is in a state of continuous integration in circumference direction. Thereby, when electric current is flowed in the core wire 11, the current flows in the portion away from the fractured portion C in circumference direction and an evasion conductive path is secured. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a covered electric wire and an electric wire with a terminal fitting.

In recent years, in the field of automobile wire harnesses and the like, aluminum wires have been used for the purpose of reducing the weight of coated wires (for example, see Patent Document 1). A conventional aluminum electric wire generally has a structure in which a core wire made of a stranded wire obtained by twisting a plurality of aluminum wires made of aluminum or an aluminum alloy is covered with an insulating coating. When connecting the terminal fitting to the end of the aluminum wire, cut the end of the insulation coating to expose the end of the core wire, and so that the wire barrel provided on the terminal fitting is held by the exposed end of the core wire It is crimped and connected.
On the other hand, particularly in such an aluminum electric wire, there is a situation that an oxide film is easily formed on the surface when the core wire is exposed to the outside air, and the contact resistance between the core wire and the wire barrel increases due to the presence of the oxide film. There are concerns. Therefore, in the crimping step, the oxide barrel is broken and peeled by crimping the wire barrel with high compression.
JP 2005-50736 A

  However, it can be said that the aluminum wire constituting the core wire is inferior in mechanical strength as compared with the copper wire, and when the wire barrel is crimped with high compression as described above, for example, it corresponds to the end of the wire barrel. If the aluminum wire is cut near the position, or if the aluminum electric wire is pulled strongly while the connected terminal fitting is accommodated in the housing, the aluminum wire may be cut similarly.

Here, in the case of an aluminum electric wire, it is highly possible that an individual aluminum element wire constituting the core wire has a strong oxide film on its surface as described above. Each aluminum wire forms a separate conductive path. Therefore, in the case where the core wire is formed of 11 aluminum strands (11-core aluminum electric wire), when the two aluminum strands are cut, the cross-sectional area is approximately (11-2 = ) It was reduced to 9/11, so that there was a problem that the current capacity was reduced.
The present invention has been completed based on the above circumstances, and an object of the present invention is to suppress a decrease in current capacity as much as possible even when a core wire breaks in a covered electric wire.

The covered electric wire of the present invention comprises a core wire made of a multi-layer wire formed by winding one metal foil from one side edge side, and an insulation made of a synthetic resin covering the periphery of the core wire It is characterized in that it is composed of a coating.
Moreover, the electric wire with a terminal metal fitting of the present invention is characterized in that a wire barrel provided in the terminal metal fitting is crimped to the end of the core wire in the above-described covered electric wire.

In the aluminum electric wire of the present invention, the core wire is formed of a multi-layered linear material in which one metal foil is wound from one side edge side. For example, when the wire barrel of the terminal fitting is crimped to the end of the core wire. Even when the outer peripheral portion of the concentric wire is broken, there is a high possibility that a part of the length region along the circumferential direction is broken in the outer layer portion of the multilayer linear object. When the core wire is formed of a multilayer wire, there is a possibility that an oxide film may be formed on the surface of each layer, and there is a possibility that each layer is insulated in the radial direction. Are wound together, so that each layer is in a continuous and integral state in the circumferential direction.
Therefore, when a current flows through the core wire, it may be interrupted before and after the axial direction across the fractured portion formed in the layer, but can flow in a portion deviated in the circumferential direction from the fractured portion, so to avoid the conductive path As a result, the current capacity in the core wire can be suppressed as much as possible.

  The metal foil may be an aluminum foil. This is particularly useful for aluminum wires that can easily form oxide films.

  According to the present invention, it is possible to suppress the current capacity from being reduced as much as possible even when the core wire is broken in the covered electric wire.

<Embodiment>
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
In this embodiment, an aluminum electric wire 10 is exemplified as a covered electric wire, and a female terminal fitting 20 (hereinafter referred to as a female terminal fitting 20) is connected to the end of the aluminum electric wire 10.

The aluminum electric wire 10 includes an aluminum core wire 11 and an insulating coating 12 made of a synthetic resin so as to cover the core wire 11.
In the present embodiment, the structure of the core wire 11 is characteristic, and as shown in FIG. 4, a strip-shaped aluminum foil 15 is provided as a material. The aluminum foil 15 is stipulated by JIS that aluminum is thinly rolled to a thickness of 0.2 mm to 0.006 mm.

As shown in FIG. 5, the aluminum foil 15 is wound in close contact with one side edge 15 </ b> A so as to form a multi-layer linear shape 17. The linear object 17 is the core wire 11.
As shown in FIG. 6, an aluminum electric wire 10 according to the present embodiment is formed by covering the periphery of a core wire 11 made of a multilayer wire 17 with an insulating coating 12. Hereinafter, it is referred to as a multilayer aluminum wire 10 as appropriate.

In addition, as an aluminum electric wire to compare, as shown in FIG.8 and FIG.9, the core wire 2 which consists of the strand wire which twisted the several aluminum strand 3 made from aluminum or aluminum alloy was covered with the insulation coating 4, A multi-core type aluminum electric wire 1 is exemplified.
Then, in the multi-layered aluminum electric wire 10 in which the core wire 11 is formed of the multi-layer linear object 17 as in this embodiment, as shown in FIG. In the case where the electric wire 1 (the number of the aluminum strands 3 is 11 and the outer diameter of the core wire 2 is 1 mm) and the allowable current is comparable, the aluminum foil 15 as the material of the multilayer wire 17 is shown in FIG. As shown in FIG. 5, a material having a thickness t of 0.1 mm and a width w of 8.5 mm is applied.

The female terminal fitting 20 is formed by pressing a metal plate excellent in conductivity, for example, a plate material made of a copper alloy with Sn (tin) plating, as shown in FIG. In this structure, a wire barrel 25 and an insulation barrel 26 are provided behind a terminal connection portion 21 having a substantially rectangular tube shape that is electrically connected to a mating male terminal fitting (not shown).
An elastic contact piece 23 is provided inside the terminal connection portion 21 so as to be folded back from the front edge of the bottom plate 22, and the tab of the mating male terminal fitting described above is connected to the terminal connection portion 21 from the front. By inserting and elastically contacting the elastic contact piece 23, the male terminal fitting and the female terminal fitting 20 are electrically connected.

  The wire barrel 25 is of an open barrel type, and is formed in a form in which a pair of wide barrel pieces 25 </ b> A rise from the left and right side edges of the bottom plate 22 so as to face each other. The wire barrel 25 is crimped and crimped to the end of the core wire 11 of the aluminum electric wire 10 described above. For example, as shown in FIG. 2, the end of the core wire while both barrel pieces 25 </ b> A abut each projecting end. It is designed so that it can be caulked into a so-called heart shape by embrace the outer periphery of the frame from both the left and right sides. In FIG. 2, the cross section of the core wire 11 is schematically shown as a whole.

  The insulation barrel 26 is also of an open barrel type, and a pair of left and right barrel pieces 26A that are narrower and taller than the barrel pieces 25A on the wire barrel 25 side are similarly connected to each other from the left and right side edges of the bottom plate 22. It is formed so as to face each other. The insulation barrel 26 is caulked and crimped to the remaining end of the insulation coating 12 of the aluminum electric wire 10. For example, both the barrel pieces 26 </ b> A overlap each protruding end and the end of the insulation coating 12. In this way, the outer periphery of the frame is embraced from both the left and right sides so that it can be caulked into a so-called overlap type.

The operation | work which connects the female terminal metal fitting 20 to the terminal of the multilayer type aluminum electric wire 10 is performed as follows.
First, the end of the insulating coating 12 of the aluminum electric wire 10 is peeled off, and the end of the core wire 11 is exposed over a predetermined length. From this state, the female terminal fitting 20 is crimped and connected to the end of the aluminum electric wire 10 by the crimping device. Specifically, the crimping device is provided with an anvil and a crimper, and the core wire is connected to the wire barrel 25 of the female terminal fitting 20. 11 is set in a state where the remaining ends of the insulation coating 12 are arranged with respect to the insulation barrel 26, and both barrels 25 and 26 are connected to the anvil and the crimper. It is clamped between them. As a result, the insulation barrel 26 is caulked in an overlap type with respect to the end of the insulating coating 12, and the wire barrel 25 is caulked in a heart shape with respect to the end of the core wire 11. Thereby, the operation | work which connects the female terminal metal fitting 20 to the terminal of the aluminum electric wire 10 is complete | finished.

  A plurality of the aluminum electric wires 10 with the female terminal fittings 20 formed as described above are gathered to form a harness. For example, the female terminal fittings 20 at the terminals of the aluminum electric wires 10 are accommodated in the female housing, so that a predetermined vehicle The female housing is fitted to the mating male housing, and the corresponding female terminal fitting 20 and the male terminal fitting are electrically connected to each other.

  Here, the aluminum electric wire 10 has a situation in which an oxide film is easily formed on the surface of the core wire 11 when the outside air touches the surface. In order to peel off the oxide film, the wire barrel 25 is caulked with high compression, that is, crimped in the crimping process. Specifically, the height of the crimped portion of the wire barrel 25 is managed. When the wire barrel 25 is pressure-bonded with high compression in this way, the oxide film formed on the outer peripheral surface of the core wire 11 is broken and peeled to reveal a new surface, and this new surface comes into contact with the inner surface of the wire barrel 25. As a result, the contact resistance decreases.

  On the other hand, when the wire barrel 25 is crimped with high compression as described above, for example, a large shearing force acts on the outer peripheral portion of the core wire 11 in the vicinity of the position corresponding to the end portion of the wire barrel 25, leading to breakage, Even when the aluminum terminal 10 is pulled in a state where the female terminal fitting 20 is retained in the female housing without being broken at the time of crimping, there is a possibility of breaking similarly at the same location.

  For comparison, FIG. 9 shows a portion where the wire barrel 25 is crimped to the core wire 2 of the terminal in the above-described 0.75 sq multi-core wire type aluminum electric wire 1 (FIG. 8). In particular, when crimped with high compression, a large shearing force acts on the outer peripheral portion of the core wire 2 near the position corresponding to the end of the wire barrel 25. In this case, the aluminum wire 3 positioned on the outer peripheral portion is cut. Alternatively, when the aluminum electric wire 1 is pulled in a state where the female terminal fitting 20 is retained and accommodated in the female housing, the aluminum wire 3 may be similarly cut.

  In such a multi-core wire type aluminum electric wire 1, there is a high possibility that the individual aluminum strands 3 constituting the core wire 2 can be strongly oxidized on their surfaces, and the aluminum strands 3 are insulated from each other. In other words, each aluminum wire 3 forms an independent conductive path. Therefore, as shown in FIG. 9, if two of the eleven aluminum wires 3 are cut (see reference numeral c in FIG. 9), the cross-sectional area is about ( 11-2 =) 9/11, and the current capacity is reduced accordingly.

Also in the case of the multilayer type aluminum electric wire 10 of the present embodiment, as described above, the outer peripheral portion of the core wire 11 near the position corresponding to the end portion of the wire barrel 25 as the wire barrel 25 is crimped with high compression. However, in this case, as shown in a broken portion C in FIG. 7, a part of the length region along the circumferential direction is broken in the outer layer portion of the multilayer linear object 17 constituting the core wire 11. There is a high possibility of staying.
Even when the core wire 11 is formed of the multilayer wire 17, there is a high possibility that an oxide film is similarly formed on the surface of each layer, and it can be said that the respective layers are insulated in the radial direction. Since the aluminum foil 15 of the sheet is wound, each layer is in a continuous and integral state in the circumferential direction.

  Therefore, when a current flows through the core wire 11, the current does not flow before and after the broken portion C formed in the layer in the axial direction, but it can flow in a portion deviated from the broken portion C in the circumferential direction, In other words, an avoidance conductive path is secured. As a result, a decrease in current capacity in the core wire 11 can be minimized.

  Further, in the case where the core wire is formed of a single aluminum wire having a relatively large diameter, that is, a single core wire type aluminum electric wire, if the outer peripheral portion of the core wire is cracked as the wire barrel 25 is crimped, the female wire In the state where the terminal fitting 20 is housed in the housing, when the aluminum wire is subjected to vibration or the like and repeatedly subjected to bending stress, the crack may extend to the inside and the entire core wire may be cut, that is, disconnected. is there. On the other hand, in the multi-layered aluminum electric wire 10 of the present embodiment, the possibility that the entire core wire 11 is broken due to the breaking portion C extending in the circumferential direction is at most low. Is ensured and a decrease in current capacity is suppressed.

  As described above, in the aluminum electric wire 10 of the present embodiment, the core wire 11 is formed of the multilayer wire 17 in which one aluminum foil 15 is wound from the side edge 15A side. Even when the outer peripheral portion of the concentric wire 11 breaks as the wire barrel 25 of the female terminal fitting 20 is crimped, a part of the length region along the circumferential direction is torn in the outer layer portion of the multilayer wire 17. Each layer is continuously in one piece toward the inside. Therefore, an avoidance conductive path is ensured at a portion where the fracture portion C is removed, and a reduction in current capacity in the core wire 11 can be suppressed as much as possible.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
(1) About the aluminum foil used as the material of the multilayer linear material constituting the core wire, the thickness and width are not limited to the numerical values exemplified in the above embodiment, but are arbitrary according to desired conditions such as flexibility and strength. Can be selected.
(2) In the multilayer aluminum wire according to the present invention, the allowable current varies depending on the cross-sectional area of the multilayer wire constituting the core wire, and when obtaining a multilayer aluminum wire having a different allowable current, What is necessary is just to select the thickness and width | variety of aluminum foil so that a corresponding cross-sectional area may be obtained about a multilayer linear object.

(3) In the said embodiment, the case where the wire barrel provided in the female terminal metal fitting is crimped to the heart shape which embraces the outer periphery of the terminal of a core wire from both right and left sides, while both barrel pieces face each protrusion end However, in addition to this, for example, both barrel pieces may be caulked in a so-called overlap type in which the outer ends of the ends of the core wires are held from both the left and right sides while overlapping their protruding ends.
(4) Further, the wire barrel may be of a type in which a pair of left and right barrel pieces are arranged shifted in the axial direction of the core wire, or may be a single barrel piece. Furthermore, it may be a closed barrel type formed in a cylindrical shape in advance before caulking.

(5) In the above embodiment, the female terminal fitting is exemplified as the terminal fitting to be connected to the terminal of the aluminum electric wire, but other terminals such as a male terminal fitting having a male tab or an LA terminal having an eyeball-shaped connecting portion. It may be a metal fitting.
(6) Depending on conditions such as the size and shape of the terminal fitting, the terminal fitting may be provided with only the wire barrel without including the insulation barrel.
(7) The present invention is not limited to the aluminum electric wires exemplified in the above embodiment, but can be applied to all covered electric wires provided with core wires made of other metals such as copper. What is necessary is just to comprise a core wire with the multilayer linear object formed with the corresponding metal foil.

The side view which shows the electric wire with a terminal metal fitting which concerns on one Embodiment of this invention Fig. 1 is an enlarged end sectional view taken along line II-II in Fig. 1. Perspective view of female terminal fitting Perspective view of aluminum foil that is the material of the multi-layered wire that constitutes the core wire Perspective view in the middle of formation of multilayer linear object Cross section of aluminum wire Sectional drawing which shows the crimping | compression-bonding part of the terminal of the core wire in an aluminum electric wire Sectional view of a multi-core wire type aluminum electric wire according to a comparative example Sectional drawing which shows the crimping part of the terminal of the core wire

Explanation of symbols

10 ... Aluminum wire (covered wire)
11 ... Core wire 12 ... Insulation coating 15 ... Aluminum foil (metal foil)
15A ... side edge (of aluminum foil 15) 17 ... multilayer wire 20 ... female terminal fitting (terminal fitting)
25 ... Wire barrel C ... Break

Claims (3)

It is composed of a core wire made of a multi-layered wire formed by winding one metal foil from one side edge side, and a synthetic resin insulating coating covering the periphery of the core wire. A covered electric wire characterized by that. The covered electric wire according to claim 1, wherein the metal foil is an aluminum foil. An electric wire with a terminal fitting, wherein a wire barrel provided on the terminal fitting is crimped to an end of the core wire in the covered electric wire according to claim 1 or 2.

Images