JP2010010086A - Terminal metal fixture and wire with terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terminal metal fixture and a wire with a terminal which have improved thermal cycle characteristics. <P>SOLUTION: The bearing surface 27 of a wire barrel 16, that bears a wire 11, has a plurality of grooves 18 extending in a first direction of crossing the extending direction of the wire 11 which is press-fit to the wire barrel 16 and a plurality of grooves 18, crossing the extending direction and extending in a second direction which is different from the first direction, wherein both grooves are formed to cross each other on the wire barrel 16, prior to being press-fit to the wire 11. The pitch P between adjacent grooves 18 is determined to be 0.3 mm or larger to 0.8 mm or smaller. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  2. Description of the Related Art Conventionally, as a terminal fitting connected to an end of an electric wire, for example, one described in Patent Document 1 is known. The terminal fitting includes a crimping portion that is caulked so as to be held from the outside to a conductor exposed from the end of the electric wire, and a connection portion that is connected to the mating terminal connected to the crimping portion.

  When an oxide film is formed on the surface of the conductor described above, there is a concern that the contact resistance between the conductor and the crimping part is increased due to the oxide film being interposed between the conductor and the crimping part.

  Therefore, in the prior art, when the direction in which the conductor extends in the state where the crimping portion is crimped to the conductor is the X direction and the direction perpendicular to this is the Y direction inside the crimping portion (conductor side), A plurality of concave portions (serrations) having both components in the Y and Y directions are formed in two directions so as to cross each other. The recess is formed in a mesh shape as a whole.

  When the crimping portion is caulked to the conductor of the electric wire, the conductor is pressed by the crimping portion and plastically deformed in the extending direction of the conductor. Then, the oxide film formed on the surface of the conductor is peeled off by coming into sliding contact with the hole edge of the recess. Then, the new surface of the conductor comes into contact with the crimping portion. Thereby, the contact resistance between a conductor and a terminal metal fitting can be made small.

In addition, since the concave portion has both components in the X and Y directions as described above, the relative movement between the core wire and the crimping portion due to the temperature change due to the heat shock can be suppressed, so that the connection reliability is improved. This is due to the following reason. The thermal expansion coefficient differs between the core wire and the crimping part. For this reason, when an abrupt temperature change occurs like a heat shock, the core wire and the crimping part move relatively at the contact part. This relative movement occurs in both the X direction in which the electric wire extends and the Y direction orthogonal thereto. For this reason, in the prior art, a plurality of recesses (serrations) having components in both the X and Y directions intersect with each other to form a net-like shape as a whole, thereby allowing relative movement in both the X and Y directions. Is suppressed.
Japanese Patent Laid-Open No. 11-3733

  In recent years, improvement in electrical connection reliability is desired for terminal fittings and electric wires with terminals using the terminal fittings. For example, it is desired to improve the thermal cycle characteristics of measuring a change in contact resistance between an electric wire and a terminal fitting after repeating cooling and heating.

  However, according to the configuration of the conventional example, the core wire and the crimping portion move relatively in a severe situation in which cooling and heating are repeated as in the case of the thermal cycle characteristics, even if it can cope with a single heat shock. There is a possibility that it cannot be suppressed.

  This invention is completed based on the above situations, Comprising: It aims at providing the terminal metal fitting and the electric wire with a terminal which the thermal-heat cycle characteristic improved.

  The present invention is a terminal fitting, comprising: a crimping part that is crimped so as to be held in a conductor exposed at the end of an electric wire; and a connection part that extends from the crimping part and is connected to a mating terminal fitting, An arrangement surface on which the electric wire is arranged in the crimping portion intersects with an extending direction of the electric wire crimped to the crimping portion in a state before the crimping portion is crimped to the electric wire. A plurality of grooves extending in the first direction and a plurality of grooves intersecting the extending direction and extending in a second direction different from the first direction are formed to intersect each other, and the pitch between the adjacent grooves The interval P is set to 0.3 mm or more and 0.8 mm or less.

  According to the present invention, the oxide film formed on the surface of the conductor is peeled off by the edge formed at the ridge located at the boundary between the side surface of the groove and the arrangement surface of the crimping portion, and the new surface is exposed. As a result, the electric wire and the terminal fitting are electrically connected. Thereby, the contact resistance between the conductor and the terminal fitting is reduced.

  Further, according to the present invention, since the pitch interval P between the grooves is set to a relatively small value, the pressure bonding is performed as compared with the case where the pitch interval between the grooves is set to a relatively large value. The area occupied by the ridges of the grooves on the arrangement surface of the parts increases. Then, as a result of an increase in the area where the edge formed at the ridge portion of the groove bites into the core wire, the ridge portion cut into the core wire can hold the electric wire in a relatively large area. As a result, when heating and cooling are repeated, even if the core wire and the crimping portion move relatively due to the difference in thermal expansion coefficient, the core wire is held in the crimping portion with a relatively large area. And the relative movement between the pressure-bonding portion are suppressed. Thereby, the thermal cycle characteristics are improved.

  Note that the pitch interval P refers to the interval between the central portion in the width direction of one groove and the central portion in the width direction of another groove located next to it.

As embodiments of the present invention, the following embodiments are preferable.
In a state before the crimping portion is crimped to the electric wire, a ridge formed at the boundary between the side surface of one of the plurality of grooves and the arrangement surface, and positioned next to the one groove The distance between the side surface of the other groove and the ridge formed at the boundary between the arrangement surface is 0.1 mm or more and not more than the value obtained by subtracting 0.1 mm from the pitch interval. Good.

  When the metal plate material is pressed with a mold to form a terminal fitting, it is not preferable that an interval between the plurality of grooves is excessively narrow because an excessive load is applied to the mold. On the other hand, if the width dimension of the groove in the extending direction is excessively small, the width dimension of the convex portion of the mold forming the groove is excessively small, and an excessive load is applied to the mold, which is not preferable.

  According to said structure, it can suppress that an excessive load is added to a metal mold | die at the time of press work by making the space | interval of the groove | channels adjacent in the extending direction into 0.1 mm or more. Moreover, it can suppress that an excessive load is added to the metal mold | die for shape | molding a groove | channel by making it below into the value which deducted 0.1 mm from the pitch interval of the groove | channel in the extending direction.

Moreover, this invention is an electric wire with a terminal, Comprising: The electric wire containing a conductor and the terminal metal fitting crimped | bonded to the terminal of the said electric wire are provided.
The conductor may be made of aluminum or an aluminum alloy.

  When the conductor is made of aluminum or an aluminum alloy, an oxide film is relatively easily formed on the surface of the conductor. The above configuration is effective when an oxide film is easily formed on the surface of the conductor.

  When the compression ratio of the conductor crimped by the crimping portion is a percentage of the cross-sectional area of the conductor after the crimping portion is crimped, with respect to the cross-sectional area of the conductor before the crimping portion is crimped, The compression rate may be 40% or more and 70 or less.

  In order to break the oxide film formed on the surface of the conductor and reduce the contact resistance, it is necessary to caulk the crimping portion to the conductor with a high compression rate. According to said structure, a crimping | compression-bonding part is crimped | bonded to an electric wire with a comparatively high compression rate that a compression rate is 40% or more and 70% or less. Thereby, the oxide film formed on the surface of the conductor can be effectively peeled off.

  ADVANTAGE OF THE INVENTION According to this invention, the thermal cycle characteristic between an electric wire and a terminal metal fitting can be improved.

  An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, this embodiment is a terminal-attached electric wire in which a female terminal fitting (corresponding to the terminal fitting of the present invention) 12 is crimped to a core wire (corresponding to the conductor of the present invention) 13 exposed from the end of the electric wire 11. 10.

(Wire 11)
As shown in FIG. 1, the electric wire 11 includes a core wire 13 formed by twisting a plurality of fine metal wires, and an insulating coating 14 made of an insulating synthetic resin surrounding the outer periphery of the core wire 13. As the metal thin wire, any metal such as copper, copper alloy, aluminum, or aluminum alloy can be used as necessary. In this embodiment, an aluminum alloy is used. As shown in FIG. 1, the insulation coating 14 is peeled off at the end of the electric wire 11 and the core wire 13 is exposed.

(Female terminal fitting 12)
The female terminal fitting 12 is formed by pressing a metal plate material into a predetermined shape using a mold (not shown). The female terminal fitting 12 includes an insulation barrel 15 that is caulked so as to embrace the outer periphery of the insulation coating 14 of the electric wire 11, and a wire barrel 16 that is caulked so as to embrace the core wire 13 from the outside. (Corresponding to the crimping portion of the present invention) and a connecting portion 17 connected to the wire barrel 16 and connected to a male terminal fitting (not shown) (corresponding to the mating terminal fitting of the present invention). As shown in FIG. 3, the insulation barrel 15 has a pair of plate shapes that protrude in the vertical direction.

  As shown in FIG. 2, the connection part 17 has comprised the cylinder shape which can insert the male tab (not shown) of a male terminal metal fitting. An elastic contact piece 26 is formed inside the connection portion 17, and the elastic contact piece 26 and the male tab of the male terminal fitting are in elastic contact with each other, so that the male terminal fitting and the female terminal fitting 12 are connected to each other. Are electrically connected.

  In the present embodiment, the female terminal fitting 12 is the female terminal fitting 12 having the cylindrical connection portion 17, but is not limited thereto, and may be a male terminal fitting having a male tab, or a through hole in a metal plate material. It is good also as what is called a LA terminal in which is formed, and it can be set as the terminal metal fitting of arbitrary shapes as needed.

(Wire barrel 16)
In FIG. 3, the principal part enlarged plan view of the wire barrel 16 in the expansion | deployment state (state before crimping | bonding to an electric wire) is shown. As shown in FIG. 3, the wire barrel 16 has a pair of plates protruding in the vertical direction in FIG. 3. The wire barrel 16 has a substantially rectangular shape when viewed from the direction penetrating the paper surface of FIG. 3 before the electric wire is crimped.

  As shown in FIG. 3, the wire barrel 16 has an arrangement surface 27 (a surface located on the front side in the direction penetrating the paper surface in FIG. 3) located on the side where the electric wires are arranged when the electric wires are crimped. A plurality of wires extending in a first direction (a direction indicated by an arrow B in FIG. 3) intersecting an extending direction (a direction indicated by an arrow A in FIG. 3) in which the core wire 13 extends in a state where the wire barrel 16 is crimped to the core wire 13. And a plurality of grooves 18 that intersect with the extending direction and extend in a second direction (direction indicated by arrow C in FIG. 3) different from the first direction are formed so as to intersect each other. The groove 18 is formed so as to be recessed from the arrangement surface 27 of the wire barrel 16 in the depth direction penetrating the paper surface. In the present embodiment, the groove 18 is a so-called groove.

  The groove 18 is formed by pressing the wire barrel 16 with a mold (not shown). The mold is formed with a plurality of protrusions (not shown) protruding at positions corresponding to the grooves 18. The plurality of grooves 18 are arranged side by side at intervals. In FIG. 3, the detailed structure inside the groove 18 is omitted.

  As shown in FIG. 3, the first direction (the direction indicated by arrow B in FIG. 3) intersects the extending direction (the direction indicated by arrow A in FIG. 3) at an angle α. In the present embodiment, the first direction intersects with the extending direction at an angle of approximately 45 °.

  The second direction (the direction indicated by the arrow C in FIG. 3) intersects the extending direction (the direction indicated by the arrow A in FIG. 3) at an angle β. In the present embodiment, the first direction intersects with the extending direction at an angle of approximately 45 °.

  The first direction and the second direction intersect with each other at an angle of approximately 90 °.

  As shown in FIG. 5, ridges 19 and 19 are formed on the wire barrel 16 at the boundary between the arrangement surface 27 of the wire barrel 16 and the two side surfaces 21 and 21 of each groove 18. The cross-sectional shape of the groove 18 has a substantially trapezoidal shape that expands in the left-right direction in FIG. 5 as it goes from the bottom surface of the groove 18 toward the ridge 19 (upward in FIG. 5). The cross-sectional shape of the groove 18 is formed symmetrically in FIG.

  As shown in FIG. 4, the pitch interval P between the adjacent grooves 18 is set to 0.3 mm or more and 0.8 mm or less. In the present embodiment, the pitch interval P is set to 0.5 mm. Note that the pitch interval P refers to the interval between the central portion in the width direction of one groove 18 and the central portion in the width direction of another groove 18 located next to it.

  The interval L between the adjacent grooves 18 is set to 0.1 mm or more, and is set to a value obtained by subtracting 0.1 mm from the pitch interval P between the grooves 18 in the extending direction. In the present embodiment, the interval L between the grooves 18 is set to 0.2 mm. In FIG. 4, the detailed structure inside the groove 18 is omitted.

  As described above, in FIG. 4, the groove 18 is recessed on the back side in the direction penetrating the paper surface with respect to the arrangement surface 27 of the wire barrel 16. On the other hand, the rectangular area surrounded by the ridge 19 is set at the same height as the arrangement surface 27 of the wire barrel 16.

  In the present embodiment, the compression ratio of the core wire 13 crimped by the wire barrel 16 is set to the cross-sectional area of the core wire 13 before the wire barrel 16 is crimped. The compression ratio is 40% or more and 70 or less. In this embodiment, it is set to 60%.

  Next, the operation and effect of this embodiment will be described. Below, an example of the attachment process of the female terminal metal fitting 12 with respect to the electric wire 11 is shown. First, a metal plate is formed into a predetermined shape by press molding using a mold. At this time, the groove 18 may be formed simultaneously.

  Then, the connection part 17 is formed by bending the metal plate material formed in the predetermined shape (refer FIG. 2). At this time, the groove 18 may be formed.

  Although not shown in detail, a plurality of convex portions are formed at positions corresponding to the grooves 18 of the wire barrel 16 in the mold when the wire barrel 16 is press-molded. The groove 18 is formed by pressing the convex portion against the wire barrel 16.

  Subsequently, the insulation coating 14 of the electric wire 11 is removed to expose the core wire 13. With the core wire 13 placed on the wire barrel 16 and the insulating coating 14 placed on the insulation barrel 15, the barrels 15 and 16 are placed outside the electric wire 11 by a mold (not shown). Tease.

  When the wire barrel 16 is caulked to the core wire 13, the core wire 13 is pressed by the wire barrel 16 and is plastically deformed and extended in the extending direction of the core wire 13. Then, the outer peripheral surface of the core wire 13 is in sliding contact with the edge formed on the ridge portion 19 of each groove 18. Thereby, the oxide film formed on the outer peripheral surface of the core wire 13 is peeled off, and the new surface of the core wire 13 is exposed. When the new surface comes into contact with the wire barrel 16, the core wire 13 and the wire barrel 16 are electrically connected.

  According to this embodiment, a relatively large stress is concentrated on the core wire 13 in the region between the plurality of grooves 18 in the wire barrel 16. Thereby, in the ridge part 19 of each groove | channel 18, the oxide film formed in the surface of the core wire 13 can be peeled reliably, and the new surface of the core wire 13 can be exposed. Thereby, the contact resistance of the core wire 13 and the wire barrel 16 can be reduced.

  Further, when the core wire 13 is pressed by the wire barrel 16, the ridge portion 19 of the groove 18 bites into the outer peripheral surface of the core wire 13. Thereby, the core wire 13 is held by the wire barrel 16.

  In the present embodiment, a plurality of grooves 18 are formed on the arrangement surface 27 of the wire barrel 16, and the pitch interval P between adjacent grooves 18 is 0.3 mm or more and 0.8 mm or less (this embodiment). Is set to 0.5 mm). Thus, in this embodiment, since the pitch interval P between the grooves 18 is set to a relatively small value, compared with the case where the pitch interval between the grooves 18 is set to a relatively large value. Thus, the area occupied by the ridge 19 of the groove 18 on the arrangement surface 27 of the wire barrel 16 increases. Then, the region where the edge formed on the ridge portion 19 of the groove 18 bites into the core wire 13 also increases. As a result, the ridge 19 that has bitten into the core wire 13 can hold the electric wire 11 in a relatively large area.

  As a result, when a force in the extending direction of the electric wire 11 is applied to the electric wire 11, the electric wire 11 is held in a relatively wide area by the ridge portion 19 that bites into the core wire 13. As a result, when heating and cooling are repeated, the core wire 13 and the wire barrel 16 are held by the wire barrel 16 in a relatively large area even if the core wire 13 and the wire barrel 16 try to move relatively due to the difference in thermal expansion coefficient. Therefore, the relative movement between the core wire 13 and the wire barrel 16 is suppressed. Thereby, the thermal cycle characteristics are improved.

  Further, when forming the female terminal fitting 12 by pressing a metal plate material with a mold, if the distance between the plurality of grooves 18 is excessively narrow, an excessive load is applied to the mold, which is not preferable. According to the present embodiment, by setting the distance L between adjacent grooves 18 in the extending direction of the electric wire 11 to 0.1 mm or more, it is possible to suppress an excessive load from being applied to the mold for forming the grooves 18. .

  In the present embodiment, the distance L between adjacent grooves 18 in the extending direction is set to a value obtained by subtracting 0.1 mm from the pitch interval P of the grooves 18 in the extending direction. It is possible to suppress an excessive load from being applied to the mold.

  In the present embodiment, the core wire 13 is made of an aluminum alloy. Thus, when the core wire 13 is made of an aluminum alloy, an oxide film is relatively easily formed on the surface of the core wire 13. This embodiment is effective when an oxide film is easily formed on the surface of the core wire 13.

  Furthermore, in order to break the oxide film formed on the surface of the core wire 13 and reduce the contact resistance, it is necessary to crimp the wire barrel 16 to the core wire 13 with a high compression rate. According to this embodiment, the wire barrel 16 is crimped to the electric wire 11 at a relatively high compression rate such that the compression rate is 40% or more and 70% or less. Thereby, the oxide film formed on the surface of the core wire 13 can be effectively peeled off. The compression ratio can be changed as appropriate within the above range. For example, it can be 50% or more and 60% or less, or 40% or more and 50% or less when the conductor cross-sectional area of the electric wire 11 is large. it can.

<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 present embodiment, the angle formed by the first direction and the second direction is set to approximately 90 °, but is not limited thereto, and can be set to an arbitrary angle as necessary.
(2) The angle formed between the extending direction and the first direction can be arbitrarily set as necessary. In addition, the angle formed between the extending direction and the second direction can be arbitrarily set as necessary.
(3) In the present embodiment, the groove 18 is formed at a position slightly inside from the edge of the wire barrel 16. However, the present invention is not limited to this, and the groove 18 is formed on the arrangement surface 27 of the wire barrel 16. It is good also as a structure formed over the whole surface.

The side view which shows the electric wire with a terminal concerning the present invention Perspective view showing female terminal fitting Main part enlarged plan view showing the female terminal fitting in the unfolded state Main part enlarged plane showing groove formed in wire barrel The principal part expanded sectional view which shows the section shape of a groove

Explanation of symbols

10 ... Electric wire with terminal 11 ... Electric wire 12 ... Female terminal fitting (terminal fitting)
13 ... Core wire (conductor)
16 ... Wire barrel (crimp part)
17 ... Connecting part 18 ... Groove 19 ... Ridge part
27 ... Installation surface

Claims (5)

A crimping part that is crimped so as to embrace the conductor exposed at the end of the electric wire, and a connection part that extends from the crimping part and is connected to the mating terminal fitting,
An arrangement surface on which the electric wire is arranged in the crimping portion intersects with an extending direction of the electric wire crimped to the crimping portion in a state before the crimping portion is crimped to the electric wire. A plurality of grooves extending in the first direction and a plurality of grooves extending in a second direction different from the first direction while intersecting the extending direction are formed intersecting each other;
A terminal fitting in which a pitch interval P between adjacent grooves is 0.3 mm or more and 0.8 mm or less. In a state before the crimping portion is crimped to the electric wire, a ridge formed at the boundary between the side surface of one of the plurality of grooves and the arrangement surface, and positioned next to the one groove The interval between the side surface of the other groove and the ridge formed at the boundary between the arrangement surfaces is not less than 0.1 mm and not more than the value obtained by subtracting 0.1 mm from the pitch interval. The terminal fitting according to claim 1. The electric wire with a terminal provided with the electric wire containing a conductor, and the terminal metal fitting of Claim 1 or Claim 2 crimped | bonded to the terminal of the said electric wire. The electric wire with a terminal according to claim 3, wherein the conductor is made of aluminum or an aluminum alloy. When the compression ratio of the conductor crimped by the crimping portion is a percentage of the cross-sectional area of the conductor after the crimping portion is crimped, with respect to the cross-sectional area of the conductor before the crimping portion is crimped, The electric wire with a terminal according to claim 3 or 4, wherein the compression ratio is 40% or more and 70% or less.

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