JP2010055931A - Terminal metal fitting and electric wire with terminal metal fitting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terminal metal fitting and an electric wire with the terminal metal fitting capable of improving conductivity by enhancing removability of an oxide film formed around a core wire. <P>SOLUTION: A stepped concave part 50 of a bottom plate part 48 has a high central part in a back and forth direction, and from the high part there are formed stepped parts 51, 52 lower toward the back and forth direction. An oxide film F formed around a core wire 21 is to be broken when it is scraped by the stepped parts 51, 52 and a new surface of the core wire 21 without the oxide film F is disclosed and moreover the core wire 21 escapes to a deeper side of the stepped concave part 50 and the surface of the core wire 21 is extended to spread the new surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

When the terminal fitting is attached to the covered electric wire, the exposed core wire of the covered electric wire is crimped and connected to the terminal fitting (see Patent Document 1).
Japanese Patent Laid-Open No. 2003-31274

Here, a thin oxide film is formed around the exposed core wire by reaction with oxygen in the air, but it is desirable to break the oxide film and expose the metal substrate in order to improve conductivity. . In particular, in an electric wire whose core wire is made of an aluminum alloy, the oxide film formed on the surface of the core wire is hard and highly insulating. Therefore, it is desirable to break the wire to obtain a connection state between the metals. Therefore, in the barrel portion of Patent Document 1, a groove-like serration is recessed with a predetermined depth in order to break the oxide film.
However, the method of breaking the oxide film with serrations at a predetermined depth is not sufficient in removing the oxide film, and there is room for improvement in conductivity.

  The present invention has been completed based on the above circumstances, and provides a terminal fitting and an electric wire with terminal fitting that can improve the conductivity by improving the removability of the oxide film formed around the core wire. For the purpose.

  In the terminal fitting of the present invention, the exposed core wire of the covered electric wire is placed on the bottom plate portion, and the barrel portion extending from both side portions of the bottom plate portion is pressed so as to wrap around the core wire and is crimped to the core wire. A stepped recess formed of two or more stepped portions having a height difference along the axial direction of the core wire is formed on a surface of the bottom plate portion or the barrel portion that is in contact with the core wire. (Means 1).

In the means 1 having the above-described configuration, the stepped concave portion has a mountain shape that has a substantially central portion in the axial direction of the core wire and is lowered stepwise toward the front end side and the rear end side of the core wire. (Means 2).
According to the configuration of the means 2, the oxide film can be broken by the step portions on both the front end side and the rear end side of the core wire.

In the means 1 or means 2 having the above-described configuration, the stepped concave portion is characterized in that it is formed in both the bottom plate portion and the barrel portion (means 3).
According to the structure of the means 3, the oxide film formed around the core wire can be broken at the portion where the core wire and the bottom plate portion are in contact and the portion where the core wire and the barrel portion are in contact.

In the means 3 having the above-described configuration, the stepped recesses are characterized in that they are formed independently on the bottom plate part and the barrel part, respectively (means 4).
According to the structure of the means 4, compared with the case where it forms continuously from the step part of the bottom plate part to the step part of the barrel part, the step part of the bottom plate part and the step part of the barrel part Since a certain thickness can be provided in the intermediate portion, the strength of the terminal fitting in the portion between the step portion of the bottom plate portion and the step portion of the barrel portion can be ensured.

In the means 3 having the above-described configuration, the stepped concave portion is characterized in that it is continuously formed between the bottom plate portion and the barrel portion (means 5).
Even between the barrel portion and the bottom plate portion, the oxide film formed around the core wire can be broken.

  An electric wire with terminal fittings, wherein the exposed core wire is placed on the bottom plate portion of the terminal fitting according to any one of means 1 to means 5 and is crimped so as to wrap the core wire by the barrel portion.

At the time of crimping connection between the core wire and the terminal fitting, the core wire is pressed to the bottom plate side by the barrel portion, and the core wire located on the bottom plate portion or the barrel portion on the stepped recess is in a direction to escape into the stepped recess. Move. At this time, the oxide film formed around the core wire is broken by the stepped portion of the stepped recess, and a new surface of the core wire metal (core wire substrate without an oxide film) appears. Here, according to this configuration, since the stepped portion is formed in a stepped shape, when the core wire is further pressed by the barrel portion, a part of the metal substrate of the core wire flows deeper in the stepped concave portion. As a result, the surface of the core wire is stretched (pressed to the deeper side of the step-like recess), and the hard oxide film is broken to further widen the exposed new surface of the core wire.
That is, by forming two or more stepped portions in a step shape, not only the oxide film is broken by the number of stepped portions, but also the metal substrate in a state where the surface oxide film is broken is deeper than the stepped recessed portion. By being pushed in the direction of flow, the new surface of the metal substrate is widened, which contacts with the surface of the terminal fitting in a wide range, and sometimes congeals so as to form an intermetallic bond, thereby improving the conductivity.

<Embodiment 1>
Hereinafter, the electric wire 10 with a terminal metal fitting of Embodiment 1 which actualized this invention is demonstrated with reference to FIGS.
As shown in FIG. 1, the electric wire 10 with terminal metal fittings of the first embodiment has a terminal metal fitting 30 connected by crimping to the terminal portion of the covered electric wire 20. The device is routed between devices (not shown) such as a motor. Note that the left side of FIG. 1 is assumed to be the front and the right side is assumed to be the rear.

  The covered electric wire 20 is obtained by covering a core wire 21 formed by spirally twisting metal strands 21A made of an aluminum alloy with a resin insulating coating 22 (insulating layer). Is peeled off and the core wire 21 is exposed. In addition to the aluminum alloy, the core wire 21 may be an aluminum wire or other types of metal wires.

  The terminal fitting 30 is a so-called open barrel type, and includes a box-shaped terminal portion 31 and a wire connecting portion 40 that is continuous with the terminal portion 31 and connected to the covered electric wire 20, and has higher strength than aluminum. Made of copper alloy.

The terminal portion 31 is a box-shaped female terminal fitting 30, and electrical connection is achieved by inserting a male terminal (not shown) into the insertion hole 31A.
The electric wire connection portion 40 includes an electric wire support portion 41 that holds the covered electric wire 20 and a core wire connection portion 45 that is connected to the core wire 21.

  The electric wire support portion 41 has a pair of insulation barrels 41 </ b> A and 41 </ b> A raised from the left and right side edges of the bottom plate continuous from the core wire connection portion 45 so that the core wire 21 is wrapped around the pair of insulation barrels 41 </ b> A and 41 </ b> A. The covered electric wire 20 is held so as not to be detached or misaligned.

  The core wire connection portion 45 includes a semi-cylindrical bottom plate portion 48 and a pair of wire barrel portions 47 and 47 extending from both side portions of the bottom plate portion 48.

  As shown in FIG. 2, the wire barrel portion 47 has a long rectangular shape in the front-rear direction (axial direction), and extends in the width direction from both side portions of the bottom plate portion 48. FIG. 2 shows a developed shape (terminal metal plate) after the punching process of the metal plate material at the wire connecting portion 40.

  As shown in FIG. 1, the bottom plate portion 48 has a semi-cylindrical shape that is curved so that the central portion in the width direction is lowered, and as shown in FIG. In the wire barrel portions 47, 47, a groove-like stepped recess 50 is formed at a position extending almost from the front end to the rear end.

  As shown in FIG. 6, the inside of the stepped recess 50 has a central portion in the front-rear direction that is higher, and from there, the first stepped portion 51 and the first stepped portion 51 are lowered stepwise in both the front and rear directions. The two step portions 52 and 53 are formed by, for example, pressing. The first step portion 51 and the second step portions 52 and 53 correspond to two or more step portions having a height difference along the axial direction of the core wire 21 of the present invention.

  The first step portion 51 is a first upper surface portion 51A that is the highest and a flat surface having the same height as the upper surface 48A of the bottom plate portion 48, and a second step that is lower than the front and rear end portions of the first upper surface portion 51A. 1st side surface part 51B, 51B formed so that it might descend | fall substantially perpendicularly toward the edge part of the part 52,53. Therefore, the thickness of the first upper surface portion 51 is equal to the thickness of the bottom plate portion 48 other than the stepped recess 50.

  The second step portions 52 and 53 are formed substantially perpendicularly from the front end portion to the bottom portion 54 of the second upper surface portion 52A and the second upper surface portions 52A and 53A, which are surfaces substantially parallel to the first upper surface portion 51A. The second side surface portion 52 and the second side surface portion 53B formed substantially perpendicularly from the rear end portion of the second upper surface portion 53A toward the bottom portion 54B.

  The bottom portions 54A and 54B are flat surfaces and are formed substantially perpendicular to the second side surface portions 52B and 53B, and the front wall 55 raised substantially perpendicularly from the front end of the bottom portion 54A is the upper surface of the bottom plate portion 48. At the same time, the rear wall 56 raised substantially vertically from the rear end of the bottom portion 54B reaches the upper surface 48A of the bottom plate portion 48. In addition, the dimension of each step part 51,52,53 and the base part 54 in the front-back direction (axial direction) is substantially the same.

Next, a method for crimping the electric wire with terminal fitting will be described.
As shown in FIG. 3, the terminal fitting 30 is positioned on the anvil 70 in a state where the exposed core wire 21 of the covered electric wire 20 is placed on the wire connecting portion 40 of the terminal fitting 30 in which the terminal original plate is bent. The crimper 71 disposed above the terminal fitting 30 is lowered.

  Then, the wire barrel portions 47 and 47 of the terminal fitting 30 are deformed into a shape that wraps the core wire 21 in accordance with the inner surface shape of the crimper 71. At this time, when the core wire 21 is pressed by the wire barrel portions 47 and 47, the core wire 21 positioned on the stepped recess 50 in the bottom plate portion 48 has a space generated by the stepped recess 50 as shown in FIG. 4. S tries to escape. At this time, the oxide film F formed around the core wire 21 is rubbed and broken by the front end and the rear end (edge portions) of the first step portion 51.

  When the crimper 71 is further lowered, the core wire 21 is further pressed by the wire barrel portion 47, so that the oxide film F formed around the core wire 21 has a front end of the second stepped portion 52 as shown in FIG. 52C (edge portion) and the second stepped portion 53 rear end 53C (edge portion). At this time, the core wire 21 escapes (pushes) to a deeper portion of the stepped recess 50, that is, the bottom 54A, 54B side. As a result, the surface of the core wire 21 on the second upper surface portions 52A, 53A is stretched (in the direction of the arrow in FIG. 5), so that a new surface (portion without the oxide film F) generated on the second upper surface portions 52A, 53A. Further spread.

That is, by forming two or more stepped portions in a step shape, not only the oxide film F is broken by the number of stepped portions, but also the core wire 21 to which the oxide film F is broken is deeper in the stepped recess 50. As a result, the new surface of the core wire 21 is expanded. Thereby, the removability of the oxide film F formed around the core wire 21 is enhanced, and the conductivity is improved.
Then, when the crimper 71 is lowered to a predetermined position, as shown in FIG. 6, the core wire 21 bites into almost the entire stepped recess 50, and the crimping of the electric wire 10 with terminal fitting is finished.

<Embodiment 2>
Next, Embodiment 2 of the present invention will be described with reference to FIG. About the same structure as Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.
In the terminal fitting 30 of the first embodiment, the stepped recess 50 is formed only in the bottom plate portion 48. However, in the terminal fitting 130 of the second embodiment, not only the bottom plate portion 48 but also the bottom plate portion 48 and the wire barrel portion 47, Step-like recesses 50, 151, 152 are formed on both sides 47.

  In the left and right wire barrel portions 47, 47, stepped recesses 151, 152 are formed at the center in the width direction of each wire barrel portion 47, respectively. The stepped recesses 151 and 152 are formed in a groove shape from the vicinity of the front end of the wire barrel portions 47 and 47 to the vicinity of the rear end, and the shape thereof is the same as that of the stepped recess 50 of the first embodiment. Thus, a mountain shape is formed in which the central portion of the core wire 21 in the axial direction is high.

  In this way, the oxide film F formed around the core wire 21 can be broken both at the portion where the core wire 21 and the bottom plate portion 48 are in contact and at the portion where the core wire 21 and the wire barrel portions 47 and 47 are in contact. .

  Further, since the stepped recesses 50, 151, 152 are formed independently on both the bottom plate portion 48 and the wire barrel portions 47, 47, the stepped recesses are formed from the step portion of the bottom plate portion 48 to the wire barrel portion 47. Compared to the case where the step portions are continuously formed over the step portions (the two step portions are connected in the same cross section), the portion between the step portion of the bottom plate portion 48 and the step portion of the wire barrel portion 47 is fixed. Since the thickness can be provided, it is possible to ensure the strength of the terminal fitting at the portion between the step portion of the bottom plate portion 48 and the step portion of the wire barrel portion 47.

<Embodiment 3>
A third embodiment of the present invention will be described with reference to FIG.
In the terminal fitting 130 of the second embodiment, the stepped recesses 151 and 152 are formed independently in the bottom plate portion 48 and the wire barrel portion 47, respectively. It is formed continuously between the bottom plate portion 48 and the wire barrel portion 47.

  Specifically, as shown in FIG. 8, with respect to the stepped recesses 151 and 152 of the second embodiment, the stepped recesses 50 of the bottom plate portion 48 and the stepped recesses 151 and 152 of the wire barrel portion 47 are made continuous without interruption. In this way, the stepped recess 250 is formed.

  The shape of the stepped recess 250 is the same as that of the stepped recess 50 in all cross sections, and the inside of the stepped recess 250 is high at the center in the front-rear direction. The first step portion 251 and the second step portions 252 and 253 (two or more step portions having a height difference along the axial direction of the core wire 21) are formed in both steps, which are lowered stepwise in two steps.

  More specifically, the first step portion 251 has a first upper surface portion 251A that is the highest and a flat surface having the same height as the upper surface 48A of the bottom plate portion 48, and a lower portion from the front and rear ends of the first upper surface portion 251A. The first side surface portions 251B and 251B are formed substantially vertically toward the end portions of the second step portions 252 and 253.

  The second step portions 252 and 253 are formed substantially perpendicularly to the second upper surface portions 252A and 253A, which are substantially parallel to the first upper surface portion 251A, and from the front end portion of the second upper surface portion 252A toward the bottom portion 54A. 2 side surface part 252B, and 2nd side surface part 253B formed substantially perpendicularly toward the bottom part 54B from the rear-end part of 2nd upper surface part 253A.

The bottom portions 254A and 254B are flat surfaces and are formed substantially perpendicular to the second side surface portions 252B and 253B. A front wall 255 raised substantially perpendicularly from the front end of the bottom portion 254A is formed on the bottom plate portion 48. Along with reaching the upper surface 48A, a rear wall 2566 raised substantially vertically from the rear end of the bottom portion 254B reaches the upper surface 48A of the bottom plate portion 48.
In this way, the oxide film F formed around the core wire 21 can be broken even at a portion between the wire barrel portion 47 and the bottom plate portion 48.

<Embodiment 4>
A fourth embodiment of the present invention will be described with reference to FIG.
In the terminal fitting 30 of the first embodiment, the stepped recess 50 is shaped like a mountain with the central portion in the axial direction being higher, but the terminal fitting 330 of the fourth embodiment has the shape of the stepped recess 350 opposite to this. The valley shape is such that the central portion in the axial direction is lowered. Since other configurations are the same as those of the first embodiment, description thereof is omitted.

  As shown in FIG. 9, the stepped recesses 350 have first stepped portions 351A and 351B that are stepped downward from the upper surface 48A of the bottom plate portion 48, and portions that are further stepped down from there are first stepped portions 351A and 351B. Two step portions 352A and 352B are formed, and portions that are further lowered from there are third step portions 353A and 353B. A portion that is one step lower than the third stepped portions 353A and 353B located at the central portion in the axial direction is the lowest base portion 354 in the stepped concave portion. In addition, the dimension of the axial direction of each level | step-difference part 351A, 351B, 352A, 352B, 353A, 353B and the base part 354 is substantially the same.

<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) In the above embodiment, the stepped recesses of the terminal fitting are formed with two or three stepped portions, but the stepped recesses with more stepped portions may be formed. Good.

  (2) In the above embodiment, the mountain-shaped or valley-shaped step-shaped recess 50 is formed by changing the direction of the inclined steps of the plurality of step-shaped stepped portions, but the present invention is not limited to this. For example, it is good also as a structure which provides the some step-shaped level | step-difference part inclined in the same direction in the location where the axial direction of the core wire 21 differs.

Side view of the electric wire with terminal fittings of Embodiment 1 Partially expanded shape of terminal fitting Diagram showing crimper and anvil during crimping Side cross-sectional view of core wire and stepped recess before crimping Side sectional view showing movement of core wire in stepped recess during crimping Side sectional view of the electric wire with terminal fittings with the new surface exposed after crimping Deployment shape of terminal fitting of embodiment 2 Deployment shape of terminal fitting of embodiment 3 Sectional side view of the electric wire with a terminal metal fitting in the state where the new surface after crimping of Embodiment 4 was exposed

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Electric wire with a terminal metal fitting 20 ... Coated electric wire 21 ... Core wire 30 ... Terminal metal fitting 40 ... Electric wire connection part 41 ... Electric wire support part 47 ... Wire barrel part 48 ... Bottom plate part 50,151,152,250,350 ... Step-like recessed part 51 , 351A, 351B ... first step portion 52, 53, 352A, 352B ... second step portion 353A, 353B ... third step portion

Claims (6)

A terminal fitting in which an exposed core wire of a covered electric wire is placed on a bottom plate portion, and barrel portions extending from both side portions of the bottom plate portion are pressed so as to wrap around the core wire and are crimped to the core wire. ,
A terminal fitting in which a stepped concave portion formed of two or more step portions having a height difference along the axial direction of the core wire is formed on a surface of the bottom plate portion or the barrel portion that contacts the core wire. . 2. The terminal according to claim 1, wherein the stepped concave portion is formed in a mountain shape having a substantially central portion in the axial direction of the core wire and being lowered stepwise toward the front end side and the rear end side of the core wire. Hardware. 3. The terminal fitting according to claim 1, wherein the stepped recess is formed in both the bottom plate portion and the barrel portion. 4. The terminal fitting according to claim 3, wherein the stepped recesses are independently formed in the bottom plate part and the barrel part. 5. 4. The terminal fitting according to claim 3, wherein the stepped recess is continuously formed between the bottom plate portion and the barrel portion. An electric wire with a terminal fitting formed by placing the exposed core wire of the covered electric wire on the bottom plate portion of the terminal fitting according to any one of claims 1 to 5 and crimping the core wire so as to wrap the core wire by the barrel portion. .

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