JP2010073344A - Terminal metal fitting, and wire with terminal metal fitting - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To alleviate contact resistance by making connection with metal strands at the inside in a radial direction. <P>SOLUTION: The terminal metal fitting 10 connected to an end of a coated wire 40 made by coating a core wire 42 is provided with a bottom wall 33 where the end of the core wire 42 is arranged, a pair of crimping pieces 31A taking on a shape rising from both side edges of the bottom wall 33 and crimping the end of the core wire 42 by being bent inside and crimped, and contact parts 31C fitted further toward a chip side than striking parts 31B where the pair of the crimping pieces 31A strike each other by crimping and coming in contact with the inside of a bundle of metal strands 41 constituting the core wire 42. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a terminal fitting connected to a terminal of a covered electric wire formed by coating a core wire and an electric wire with a terminal fitting.

2. Description of the Related Art Conventionally, for example, a terminal fitting described in Patent Document 1 below is known as a terminal fitting for a wire harness of an automobile. This terminal metal fitting is configured to include a pair of caulking pieces for crimping a terminal end of a core wire in a covered electric wire covering the core wire. By the way, when an insulating coating is formed on the surface of the core wire at the time of crimping, this coating becomes an insulating layer, and there is a problem that conduction cannot be established between the core wire and the caulking piece. Therefore, it is considered that the film is scraped off to achieve electrical continuity by crimping at a compression rate as high as possible.
JP 2003-249284 A

  However, when a thick coated electric wire is used, the number of metal wires constituting the core wire increases, and thus the pressure from the caulking pieces is easily dispersed. For this reason, the coating remains on the radially inner metal strand not in contact with the caulking piece, and the contact resistance increases because conduction cannot be achieved.

  This invention is completed based on the above situations, Comprising: It aims at reducing contact resistance by taking conduction | electrical_connection with respect to the metal strand of a radial inside.

  The present invention is a terminal fitting connected to the end of a covered electric wire formed by covering a core wire, and has a bottom wall on which the end of the core wire is disposed and a form rising from both side edges of the bottom wall, and is bent inward. A pair of caulking pieces that crimp the end of the core wire by caulking, and a contact that is provided on the tip side from the abutting portion where the pair of caulking pieces meet by crimping, and contacts the inside of the bundle of metal strands that constitute the core wire It has the characteristic in the place provided with the part.

  In such a configuration, when the end of the core wire is placed on the bottom wall and the core wire is crimped with a pair of caulking pieces, the contact piece enters the inside of the bundle of metal strands constituting the core wire, The coating is removed and contact is made to allow conduction. Therefore, the contact resistance can be reduced by conducting to the radially inner metal strand that does not contact the caulking piece.

The following configuration is preferable as an embodiment of the present invention.
It is good also as a structure by which the several recessed part which a core wire cuts in with a crimping | compression-bonding is formed in the crimping surface to which the terminal of a core wire is crimped | bonded in a bottom wall and a pair of crimping piece.
Moreover, it is good also as a structure by which the several recessed part is given to the front and back both sides in a contact part.
According to such a configuration, the core wire can bite into the concave portion along with the crimping, and the opening edge portion of the concave portion can scrape off the coating of the core wire to make conduction.

As a configuration in which one of the terminal fittings is crimped to the end of the core wire in the covered electric wire in which the core wire is covered with a coating, and the contact portion is in contact with the inside of the bundle of metal wires constituting the core wire Also good.
At that time, the core wire may be made of aluminum or an aluminum alloy.

  According to the present invention, the contact resistance can be reduced by conducting to the radially inner metal strand.

<Embodiment 1>
Embodiment 1 of the present invention will be described with reference to the drawings of FIGS. As shown in FIG. 1, the terminal fitting 10 in the present embodiment includes a main body portion 20 having a rectangular tube shape and a crimping portion 30 formed at the rear of the main body portion 20. As shown in FIG. 2, the terminal fitting 10 is crimped to the end of the covered electric wire 40 by a crimping portion 30. The terminal fitting 10 is formed by punching a metal flat plate made of a copper alloy into a predetermined shape with a die to form the terminal fitting 10 in an unfolded state, and then bending the terminal fitting 10 in the unfolded state. ing. In the present embodiment, the female terminal fitting having the main body portion 20 is illustrated as the terminal fitting 10, but according to the present invention, a male terminal fitting having a tab shape may be used.

The covered electric wire 40 is an aluminum electric wire, and has a configuration in which a core wire 42 made of a plurality of metal wires 41 is covered with a covering 43 made of an insulating synthetic resin. The covered electric wire 40 of the present embodiment is a thick covered electric wire, which is a bundle of 37 metal strands 41, and the total sectional area of the bundle of these metal strands 41 is 3 mm ² . The metal element wire 41 can use any metal such as copper, copper alloy, aluminum, or aluminum alloy. In addition, the metal strand 41 of this embodiment is comprised with the aluminum alloy.

  The main body 20 is formed by bending the bottom part 22, the pair of side parts 23 rising from both side edges of the bottom part 22, and the two side parts 23 by bending each other from the upper edge of one side part 23 toward the upper edge of the other side part 23. The ceiling part 24 formed in heavy is provided.

  An elastic contact piece 21 that can be elastically displaced is formed inside the main body portion 20 by folding back from the front edge of the bottom surface portion 22 of the main body portion 20. A mating conductor (not shown) in the form of a tab can be inserted between the opposing surface (the lower surface of the ceiling portion 24) facing the elastic contact piece 21 and the elastic contact piece 21 inside the main body 20. ing.

  The distance between the elastic contact piece 21 in the natural state and the opposing surface is set to be smaller than the plate thickness of the counterpart conductor. For this reason, when the counterpart conductor is inserted between the opposing surfaces while bending the elastic contact piece 21, the counterpart conductor and the elastic contact piece 21 are elastically contacted and electrically connected.

  The crimping portion 30 includes a wire barrel portion 31 and an insulation barrel portion 32 disposed behind the wire barrel portion 31. The crimping portion 30 has a bottom wall 33 that extends in the front-rear direction (the axial direction of the core wire 42) continuously with the bottom surface portion 22 of the main body portion 20.

  The wire barrel portion 31 includes a bottom wall 33 and a pair of caulking pieces 31 </ b> A rising from both side edges of the bottom wall 33. The wire barrel portion 31 can crimp the core wire 42 by arranging the end of the core wire 42 along the front-rear direction on the bottom wall 33 and caulking the end of the core wire 42 with both caulking pieces 31A.

  The insulation barrel portion 32 includes a bottom wall 33 and a pair of caulking pieces 32 </ b> A that rise in an opposed state from both side edges of the bottom wall 33. The insulation barrel portion 32 is capable of crimping the coating 43 and the core wire 42 by arranging a portion of the coating 43 on the bottom wall 33 and caulking the portion of the coating 43 with both caulking pieces 32A.

  Here, an insulating coating (for example, aluminum hydroxide or aluminum oxide) is formed on the surface of the core wire 42 by reacting with water or oxygen in the air. And if both 42 and 31 are connected with the film interposed between the core wire 42 and the wire barrel portion 31, there is a problem that the contact resistance increases. In that respect, in this embodiment, the compression rate is set higher than when a core wire made of a copper alloy is used, and a serration (an example of the “concave portion” of the present invention) 36 is provided in the crimping surface of the wire barrel portion 31. Therefore, the coating is scraped off to make conduction. The serration 36 has a net-like shape as a whole, and is configured by forming a groove obliquely with respect to the axial direction of the core wire 42 on the crimping surface to which the core wire 42 is crimped in the wire barrel portion 31.

  However, when a thick covered electric wire is used as in the present embodiment, the number of the metal strands 41 increases, so that the pressure from the caulking pieces 31A is easily dispersed. Therefore, the coating tends to remain on the radially inner metal wire 41 that does not come into contact with the caulking piece 31 </ b> A, and the contact resistance increases due to the inability to conduct. For this reason, in order to establish electrical continuity with the radially inner metal wire 41, it is necessary to remove the coating as a premise.

  Therefore, in the present embodiment, the contact portion 31C is provided on the tip side from the contact portion 31B where both the caulking pieces 31A come into contact when the crimping is completed. The contact portion 31 </ b> C is configured to contact the inside of a bundle of metal strands 41 that constitute the core wire 42. Serrations 36 are provided on both front and back sides of the contact portion 31C. Thereby, the coating can be scraped off by bringing the serration 36 into contact with the inside of the bundle of the metal wires 41.

  Further, the contact portion 31 </ b> C is formed so as to be wound inside the bundle of metal strands 41. The tip of the contact portion 31 </ b> C is disposed radially inward from the caulking piece 31 </ b> A and the bottom wall 33 in the core wire 42. That is, the tip of the contact portion 31 </ b> C is connected to the caulking piece 31 </ b> A and the metal element wire 41 on the radially inner side that does not contact the bottom wall 33 so as to be conductive after being scraped off.

  Next, the main part of the crimping machine 50 that crimps the wire barrel part 31 and the insulation barrel part 32 will be briefly described with reference to FIGS. The wire barrel portion 31 and the insulation barrel portion 32 are placed on the anvil 51. A pair of crimpers 52 corresponding to the wire barrel portion 31 and the insulation barrel portion 32 are arranged above the anvil 51. The crimper 52 can be moved up and down by driving means (not shown). 4 to 6, only the crimper 52 corresponding to the wire barrel portion 31 is illustrated.

  The terminal fitting 10 before crimping is connected to a carrier (not shown), and the terminal fitting 10 is conveyed by sliding the carrier. A slide cutter for cutting the carrier is provided behind the anvil 51 so as to be movable up and down. The carrier is cut by shearing by lowering the slide cutter almost simultaneously with the timing when the crimper 52 is lowered.

  The present embodiment is configured as described above, and its operation will be described subsequently. First, the covering 43 is peeled off at the end of the covered electric wire 40 to expose the core wire 42. Next, as shown in FIG. 4, the end of the core wire 42 is disposed on the bottom wall 33 of the wire barrel portion 31, and the covering 43 is disposed on the bottom wall 33 of the insulation barrel portion 32. Thereafter, when the crimper 52 is lowered toward the anvil 51, the contact portion 31C comes into contact with the crimper 52 and is bent inward as shown in FIG. In addition, since the contact part 31C is serrated 36 on both front and back sides, the rigidity is lower than the part other than the contact part 31C in the caulking piece 31A.

  Subsequently, when the crimper 52 is lowered, as shown in FIG. 5, the contact portion 31 </ b> C comes into contact with the bundle of metal strands 41, is further bent inward, and is pushed into the inside so as to scrape the bundle of metal strands 41. It is. Further, when the crimper 52 is lowered and the crimper 52 reaches the bottom dead center, the core wire 42 is crimped by the caulking piece 31A as shown in FIG. On the other hand, the covering 43 is crimped together with the core wire 42 by the caulking piece 32 </ b> A of the insulation barrel portion 32. At almost the same time, the carrier is cut by the slide cutter, and the electric wire with terminal fitting is completed.

  As a result of this crimping, the radially outer metal wire 41 in contact with the caulking piece 31A bites into the inside of the serration 36 of the caulking piece 31A and the bottom wall 33, and the opening edge portion of the serration 36 caulks off the coating. It is connected to the piece 31A so as to be conductive. On the other hand, the metal wire 41 on the radially inner side bites into the serration 36 of the contact portion 31C, and the opening edge portion of the serration 36 is connected to the contact portion 31C in a conductive manner by scraping the film. Therefore, since it is possible to conduct not only the radially outer metal element wire 41 but also the radially inner metal element wire 41, the contact resistance can be reduced.

As described above, in the present embodiment, when the coated electric wire 40 is crimped, the metal strand 41 on the radially inner side that does not contact the caulking piece 31A is brought into contact with the contact portion 31C while the coating is being scraped by the serration 36. It can be connected in a conductive manner. In particular, when a thick covered electric wire 40 having a cross-sectional area of 3 mm ² is used, the number of metal wires 41 increases, and the number of radially inner metal wires 41 that do not contribute to conduction also increases. However, in this embodiment, since the metal wire 41 on the radially inner side can contribute to conduction by the contact portion 31C, the contact area of the conductive metal wire 41 can be greatly increased, and the contact resistance is reduced. Can be reduced.

<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) Although the serration 36 is provided on the crimping surface of the wire barrel portion 31 in this embodiment, the serration 36 may not be provided when crimping a core wire made of a copper alloy, for example.

  (2) Although the serrations 36 are provided on both the crimping surface of the wire barrel portion 31 and the contact portion 31C in this embodiment, the serrations 36 may be provided only on the crimping surface of the wire barrel portion 31 according to the present invention. .

  (3) In the present embodiment, the contact portion 31C is pushed into the inside so as to divide the bundle of the metal strands 41. However, according to the present invention, the crimping by the caulking pieces 31A proceeds and the bundle of the metal strands 41 is somewhat hard. In this state, the contact portion 31 </ b> C may be pierced into the bundle of metal strands 41.

(4) Although this embodiment uses a thick covered electric wire 40 having a cross-sectional area of 3 mm ² , according to the present invention, the invention is not limited to this covered electric wire 40, and other cross-sectional areas are covered. An electric wire may be used. For example, the following covered electric wires are mentioned.
Aluminum electric wire 1 Size: 1.25mm ² (The number of metal wires 41 is 16)
Aluminum wire 2 Size: 2mm ² (19 metal strands 41)
Aluminum wire 3 Size: 2.5mm ² (19 metal strands 41)

The perspective view of the terminal metal fitting of this embodiment The side view which showed a mode that the terminal metal fitting of this embodiment was crimped | bonded to the terminal of the covered wire AA line sectional view of FIG. Sectional drawing which showed the state by which the contact part of this embodiment contacted the crimper and was bent inside Sectional drawing which showed the state which the contact part of this embodiment contacted the core wire Sectional drawing which showed the state which the contact part of this embodiment is contacting the inside of the bundle | flux of a metal strand

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Terminal metal fitting 20 ... Main-body part 31A ... Caulking piece 31B ... Contact part 31C ... Contact part 33 ... Bottom wall 36 ... Serration (recessed part)
40 ... covered wire 41 ... metal wire 42 ... core wire 43 ... covered

Claims (5)

A terminal fitting connected to a terminal of a covered electric wire covering a core wire,
A bottom wall on which the end of the core wire is disposed;
A pair of caulking pieces that form a form rising from both side edges of the bottom wall, and crimp the terminal end of the core wire by bending and caulking inside,
A terminal fitting provided with a contact portion that is provided on a distal end side from a contact portion where the pair of caulking pieces abut against each other by crimping and contacts a bundle of metal strands constituting the core wire. 2. The terminal fitting according to claim 1, wherein a plurality of recesses into which the core wire bites in with crimping are formed on a crimping surface of the bottom wall and the pair of caulking pieces on the side to which the terminal of the core wire is crimped. The terminal fitting according to claim 2, wherein the plurality of recesses are provided on both front and back sides of the contact portion. The terminal fitting as described in any one of Claim 1 thru | or 3 is crimped | bonded to the terminal of the said core wire in the covered electric wire in which a core wire is covered by coating | cover, and the said contact part comprises the said core wire. An electric wire with terminal fittings in contact with the inside of a bundle of metal wires. The said core wire consists of aluminum or aluminum alloy, The electric wire with a terminal metal fitting of Claim 4 characterized by the above-mentioned.

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