JP5593354B2 - Terminal fittings and covered electric wires with terminal fittings - Google Patents

Description

  The present invention relates to a terminal fitting to be crimped to a terminal portion of a covered electric wire, and a covered electric wire with a terminal fitting.

  In general, a terminal fitting is attached to a terminal portion of a covered electric wire in which an insulating coating is formed on an outer peripheral portion of a core wire formed by twisting conductor wires. As the terminal fitting, there is known a crimp terminal that includes a U-shaped wire barrel portion that grips the core wire portion from which the insulation coating has been removed, and is electrically connected to the covered electric wire by caulking the wire barrel portion. Yes.

  Usually, a locking portion called serration is formed on the inner surface of the wire barrel portion (the surface in contact with the core wire). By forming the serration, the contact area between the wire barrel portion and the core wire increases, so that the electric wire holding force can be increased. In addition, since the serration edge bites into the core wire and destroys the oxide film formed on the surface of the core wire, good electrical connectivity can be obtained. For example, in a terminal fitting attached to a copper wire, a plurality of (for example, three) grooves extending in the width direction (direction orthogonal to the axis of the core wire) are separated in the arrangement direction of the core wire (longitudinal direction of the core wire). A lateral groove type serration formed in general is generally used.

  In recent years, aluminum wires have begun to be used as an alternative to copper wires in the field of wire harnesses used for in-car wiring of automobiles. However, aluminum has physical properties such as that the surface is more easily oxidized than copper, the electrical conductivity is low, and the tensile strength is low. It becomes difficult to ensure (electric wire retainability, electrical connectivity, etc.).

  Therefore, as a technique suitable for a terminal fitting for an aluminum electric wire, a concave-convex serration has been proposed in which fine concave portions or convex portions having a rectangular shape are dotted on the wire barrel portion (for example, Patent Documents 1 and 2). Moreover, as another aspect of serration, what formed the step-shaped recessed part along the longitudinal direction of the core wire in the wire barrel part (for example, patent document 3), and what formed the several cylindrical recessed part (for example, patent document) There is also 4).

JP 2010-10000 A JP 2010-272508 A JP 2010-55931 A JP 2009-193890 A

  However, when crimping a conventional terminal fitting to a covered electric wire, it is necessary to crimp the wire barrel portion with a high compression force (for example, 27 MPa) in order to bring the terminal fitting and the core wire into close contact with each other. For this reason, there is a possibility that the deformation (crushing) of the conductor wire after caulking becomes large and the tensile strength is lowered.

  An object of the present invention is to provide a terminal fitting and a covered electric wire with a terminal fitting capable of improving the crimp connection reliability.

The terminal fitting according to the present invention is a terminal fitting to be attached to the terminal portion of a covered electric wire in which an insulation coating is applied to the outer peripheral surface of a core wire formed by twisting a plurality of conductor strands,
A wire barrel portion to be crimped so as to grip and wrap the core wire;
A connection part connected to the connection partner,
On the inner surface of the wire barrel portion, there are a plurality of grooves having a circular arc shape having a diameter substantially the same as the diameter of the conductor wire corresponding to the number of conductor wires on the outermost periphery of the core wire along the twist direction of the core wire. In addition to the formation, serrations are formed in the groove.

  The covered electric wire with terminal fitting according to the present invention is characterized in that the terminal fitting is crimped to the terminal portion of the covered electric wire.

According to the present invention, since the wire barrel portion is caulked in a state where the conductor wire is fitted in each groove portion and the core wire is fixed, a uniform pressure is applied to the conductor wire. Therefore, deformation of the conductor wire during crimping is suppressed, so that the tensile strength can be improved.
In addition, since the serration formed on the inner surface of the groove portion surely bites into the core wire, the oxide film formed on the surface of the conductor element wire can be efficiently broken and good electrical connectivity can be obtained. Furthermore, since the adhesiveness between the terminal fitting and the core wire is dramatically improved, high electric wire retainability can be ensured. Therefore, according to the present invention, the crimp connection reliability is remarkably improved.

It is a perspective view which shows the covered electric wire used by embodiment. It is a perspective view which shows the terminal metal fitting which concerns on embodiment. It is a perspective view which shows the state which crimped | bonded the terminal metal fitting to the covered electric wire. It is a top view which shows the state which expand | deployed the wire barrel part. It is a perspective view which expands and shows a wire barrel part. It is sectional drawing of a wire barrel part when a terminal metal fitting is crimped | bonded to the covered electric wire. It is a top view which shows the state which expand | deployed the wire barrel part which concerns on a modification.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing a covered electric wire 2 used in the embodiment. As shown in FIG. 1, the covered electric wire 2 has a configuration in which an insulating coating 22 is applied to the outer peripheral surface of a core wire 21 formed by twisting a plurality of conductor strands 211.
The core wire 21 has a configuration in which seven conductor strands 211 having an outer diameter of 0.32 mm are twisted together. The conductor wire 211 is made of, for example, aluminum or an aluminum alloy.
The insulating coating 22 is made of, for example, a resin such as vinyl chloride, and is finished so that, for example, the outer diameter of the covered electric wire 2 is 1.0 mm (0.5 mm ^{2 in} cross-sectional area).
The outer diameter, the number of twists, the material of the conductor wire 211, the thickness, the material, etc. of the insulating coating 22 are not limited to those described here.

  When the terminal fitting 1 according to the embodiment is attached to the covered electric wire 2, the end portion of the covered electric wire 2 is in a state where the insulating coating 22 having a predetermined length is peeled off and the core wire 21 is exposed. And the covered electric wire (the covered electric wire with a terminal metal fitting shown in FIG. 3) with which the terminal metal fitting 1 was mounted | worn is used, for example for the wiring etc. of a motor vehicle.

FIG. 2 is a perspective view showing the terminal fitting 1 according to the embodiment. FIG. 3 is a perspective view showing a state in which the terminal fitting 1 is crimped to the covered electric wire 2.
A terminal fitting 1 shown in FIGS. 2 and 3 is a female terminal fitting to which a male terminal fitting of a connector is connected, for example. The terminal fitting 1 is formed into a predetermined shape by pressing a metal plate material made of, for example, brass or phosphor bronze.

  As shown in FIGS. 2 and 3, the terminal fitting 1 is connected to the connecting portion 11 connected to the male terminal fitting to be connected, the wire barrel portion 10 connected to the connecting portion 11, and the wire barrel portion 10. A covering barrel portion 12 is provided.

  The connection part 11 is formed in a cylindrical shape into which a male tab of a male terminal fitting (not shown) can be inserted, and has an elastic contact piece 11a inside. When the elastic contact piece 11a and the male tab of the male terminal fitting (not shown) are in elastic contact, the terminal fitting 1 and the male terminal fitting (not shown) are electrically connected.

The wire barrel part 10 is formed into a U-shaped cross section as a whole, and is crimped so as to grip and wrap the core wire 21 of the terminal part of the covered electric wire 2 (see FIG. 3). Moreover, in order to improve the crimping connection reliability of the terminal metal fitting 1 on the inner surface of the wire barrel part 10, the characteristic process is given. The inner surface shape of the wire barrel part 10 will be described later.
The covering barrel portion 12 is formed in a U-shaped cross section as a whole in the same manner as the wire barrel portion 10, and is crimped so as to grip and wrap the insulating coating 22 at the end portion of the covered electric wire 2 (see FIG. 3).

FIG. 4 is a plan view showing a state in which the wire barrel portion 10 is developed. FIG. 5 is an enlarged perspective view showing the wire barrel portion 10.
As shown in FIGS. 4 and 5, a groove portion 101 having a circular arc shape having a predetermined depth d is formed on the inner surface of the wire barrel portion 10 along the twisting direction (longitudinal direction) of the core wire 21 of the covered electric wire 2. The Here, since there are six outermost conductor wires 211 constituting the core wire 21 of the covered electric wire 2, six groove portions 101 are formed on the inner surface of the wire barrel portion 10.

In addition, the arc-shaped diameter D ₁ (see FIG. 5) defining the groove 101 is substantially the same as the diameter D ₀ of the conductor wire 211. That is, a groove portion 101 corresponding to the outer peripheral shape of the core wire 21 is formed on the inner surface of the wire barrel portion 10. When the terminal fitting 1 is crimped to the covered electric wire 2, the core wire 21 is fixed to the wire barrel portion 10 by the conductor element wires 211 being fitted in the respective groove portions 101.

  Furthermore, serrations 102 are formed in the groove portion 101 to improve the crimping connection reliability of the terminal fitting 1. The serrations 102 are convex portions or concave portions formed in the wire barrel portion 10 and have a structure that bites into the conductor wire 211 when crimped. That is, when the wire barrel portion 10 is caulked, the serrations 102 bite into the individual conductor strands 211 and destroy the oxide film formed on the surface of the conductor strands 211. The serration 102 is formed, for example, when the terminal fitting 1 is pressed.

The serrations 102 shown in FIGS. 4 and 5 are convex serrations protruding from the inner surface of the groove 101. More specifically, the serration 102 </ b> A is a partially annular convex portion formed along the arc shape of the groove 101. The serration 102A has a predetermined height (thickness) h and a predetermined width w, and is formed at a predetermined interval L in the length direction.
4 and 5, the serrations 102A are alternately arranged in the longitudinal direction in the adjacent grooves 101 and 101, but the arrangement of the serrations 102A is not particularly limited.

  When the terminal metal fitting 1 is crimped to the covered electric wire 2, the core wire 21 exposed from the terminal portion of the covered electric wire 2 is placed on the wire barrel portion 10 of the terminal metal fitting 1, and the insulating coating 22 at the terminal portion of the covered electric wire 2 is a terminal. It is placed on the covering barrel portion 12 of the metal fitting 1. In this state, the terminal fitting 1 is positioned on the anvil (iron base), the crimper disposed above the terminal fitting 1 is lowered, and the wire barrel portion 10 is crushed with a predetermined compressive force. Thereby, the wire barrel part 10 is crimped so that the core wire 21 may be wrapped according to the inner surface shape of a crimper (refer FIG. 6).

  At this time, each of the six conductor strands 211 arranged on the outermost periphery of the covered electric wire 2 is dropped into the groove 101. In the case of semi-automatic crimper crimping, for example, an operator may adjust by visual observation. Further, in the case of automatic crimping, for example, the mounting state of the core wire 21 on the wire barrel portion 10 is monitored, and the covered electric wire 2 is rotated based on a signal indicating the mounting state (for example, a video signal from the monitor). It is sufficient to provide a mechanism for making it.

The terminal fitting 1 is crimped to the covered electric wire 2 by the above-described crimping process. The cross section of the wire barrel part 10 after crimping is as shown in FIG. That is, the outermost conductor wire 211 is dropped into the groove 101 and fixed, and the serrations 102A formed in the groove 101 bite at right angles so as to draw an arc with respect to the conductor wire 211.
Thereby, the oxide film formed on the surface of the conductor strand 211 is efficiently destroyed, and the new surface of the conductor strand 211 and the wire barrel portion 10 are electrically connected. Moreover, the removal of the covered electric wire 2 from the terminal fitting 1 is effectively prevented.

As described above, the terminal fitting 1 according to the embodiment includes the wire barrel portion 10 that is crimped so as to grip and wrap the core wire 21, and the connection portion 11 that is connected to the connection partner (here, the male terminal fitting). Is provided.
Then, on the inner surface of the wire barrel portion 10, a plurality of grooves 101 (here, six) having a circular arc shape corresponding to the outer peripheral shape of the core wire 21 are formed, and serrations 102 are formed in the grooves 101.

  Specifically, the serration 102 includes a convex serration 102 </ b> A that protrudes from the inner surface of the groove 101. More specifically, the serration 102A has a partial annular shape formed along the arc shape of the groove 101, and is formed at predetermined intervals in the longitudinal direction.

  According to the terminal fitting 1, the conductor strands 211 are fitted in the respective groove portions 101, and the wire barrel portion 10 is caulked with the core wire 21 fixed, so that a uniform compressive force is applied to the conductor strands 211. It becomes. Therefore, deformation of the conductor wire 211 during crimping is suppressed, so that the tensile strength can be improved. Moreover, even if the crimping conditions (compression force) are relaxed compared to the case of crimping a conventional terminal fitting, an equivalent tensile strength can be realized.

  In addition, since the serration 102A formed on the inner surface of the groove 101 surely bites into the core wire 21, the oxide film formed on the surface of the conductor wire 211 can be efficiently destroyed to obtain good electrical connectivity. it can. Furthermore, since the adhesion between the terminal fitting 1 and the core wire 21 is drastically improved, high electric wire retainability can be ensured. Therefore, according to the terminal fitting 1, the crimp connection reliability is significantly improved.

  In particular, when the conductor wire 211 is made of aluminum or an aluminum alloy, a strong oxide film is easily formed on the surface, which is useful because deformation of the wire at the time of crimping increases.

Here, when the diameter of the conductor wires 211 to the D _0, the groove 101 of the depth d (see FIG. 5) is preferably 0.1D is ₀ or more 0.5 D ₀ less. For example, when the conductor element wire diameter D ₀ is 0.4 mm, the preferable range of the depth d of the groove 101 is 0.04 mm or more and 0.20 mm or less. By setting the depth d of the groove portion 101 within the above range, one conductor strand 211 can be dropped into each groove portion 101 at the time of crimping and can be easily restrained.
Note that the gap g (see FIG. 5) between the adjacent groove portions 101 and 101 depends on the depth d of the groove portion 101. That is, as the depth d of the groove portion 101 is shallower, the interval g becomes wider, and as the depth d becomes deeper, the interval g becomes narrower. For example, when the depth d of the groove portion 101 is 0.5D ₀ (corresponding to the radius of the conductor element wire 211), the interval g is zero.

In addition, the height h (see FIG. 5) of each serration 102A is preferably 0.1 d or more and 0.5 d or less (d: depth of the groove portion 101). Furthermore, the serration 102A preferably has a width w (see FIG. 5) of 0.1 mm to 0.5 mm and an interval L (see FIG. 5) of 0.1 mm to 1.0 mm.
As a result, the oxide film formed on the surface of the conductor wire 211 is efficiently destroyed and the electrical connectivity is improved without the tensile strength of the conductor wire 211 being lowered by the biting of the serration 102A into the conductor wire 211. While being able to improve, desired electric wire retainability is securable.

[Modification]
FIG. 7 is a plan view showing a state where the wire barrel portion 10 according to the modification is developed.
As shown in FIG. 7, in the wire barrel portion 10 according to the modified example, a groove portion having an arc-shaped cross section having a predetermined depth d along the twist direction of the core wire 21 of the covered electric wire 2 on the inner surface of the wire barrel portion 10. 101 is formed. The groove 101 is formed with a convex serration 102 for improving the crimping connection reliability of the terminal fitting 1. These configurations are the same as those of the wire barrel portion 10 (see FIG. 4) shown in the embodiment.

In the modified example, a serration 102B having a rectangular shape (including a parallelogram shape) is employed as the serration 102. The serrations 102B are formed at predetermined intervals along the arc shape of the groove 101 and at predetermined intervals in the longitudinal direction. That is, the serrations 102 </ b> B are arranged vertically and horizontally in the respective groove portions 101.
In the wire barrel portion 10, by forming the serration 102B described above in the groove portion 101, the same effect as described in the embodiment can be obtained.

Here, the height h (see FIG. 5) of each serration 102B is preferably 0.1 d or more and 0.5 d or less (d: depth of the groove portion 101). Further, the serration 102B has a length of one side of 0.1 mm to 0.3 mm, a longitudinal interval of 0.2 mm to 2 mm, and two or three serrations 102B are formed along the arc shape of the groove 101. preferable.
As a result, the oxide film formed on the surface of the conductor wire 211 is efficiently destroyed and the electrical connectivity is improved without the tensile strength of the conductor wire 211 being lowered by the biting of the serration 102B into the conductor wire 211. While being able to improve, desired electric wire retainability is securable.

As mentioned above, the invention made by the present inventor has been specifically described based on the embodiment. However, the present invention is not limited to the above embodiment, and can be changed without departing from the gist thereof.
For example, the shape of the serration formed in the groove 101 is not limited to the serrations 102A and 102B shown in the embodiment and the modification. The serration 102 formed in the groove 101 may be a concave serration such as a groove or a rectangular recess, or may be a cylindrical convex or concave serration.

In the embodiment, a female terminal fitting having a female connecting portion is shown as the terminal fitting 1 to which the present invention can be applied, but the configuration of the connecting portion 11 is not limited to that described in the embodiment. For example, the present invention can be applied to various terminal fittings having a wire barrel portion, such as male terminal fittings, ring-type terminal fittings, hook-type terminal fittings, and Y-type terminal fittings.
Further, the conductor wire 211 of the covered electric wire 2 may be made of copper or a copper alloy.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Terminal metal fitting 10 Wire barrel part 101 Groove parts 102, 102A, 102B Serration 11 Connection part 12 Covered barrel part 2 Covered electric wire 21 Core wire 211 Conductor wire 22 Insulation coating

Claims (11)

A terminal fitting to be attached to a terminal portion of a covered electric wire having an insulation coating applied to the outer peripheral surface of a core wire formed by twisting a plurality of conductor wires,
A wire barrel portion to be crimped so as to grip and wrap the core wire;
A connection part connected to the connection partner,
On the inner surface of the wire barrel portion, there are a plurality of grooves having a circular arc shape having a diameter substantially the same as the diameter of the conductor wire corresponding to the number of conductor wires on the outermost periphery of the core wire along the twist direction of the core wire. A terminal fitting characterized by being formed and having serrations formed in the groove. When the diameter of the conductor element wire and the D _0, the depth of the groove is, the terminal fitting according to claim 1, characterized in that 0.1 D ₀ or 0.5D is ₀ or less.   The terminal fitting according to claim 1, wherein the serration is a convex serration protruding from the inner surface of the groove. When the depth of the groove is d,
The terminal fitting according to claim 3, wherein a height of the convex serration is 0.1 d or more and 0.5 d or less.   5. The terminal according to claim 3, wherein the convex serration has a partial annular shape formed along an arc shape of the groove portion, and is formed at a predetermined interval in a longitudinal direction. Hardware.   6. The terminal fitting according to claim 5, wherein the convex serration has a width of 0.1 mm to 0.5 mm and an interval of 0.1 mm to 1.0 mm.   5. The terminal according to claim 3, wherein the convex serration has a rectangular shape and is formed at predetermined intervals along the arc shape of the groove and at predetermined intervals in the longitudinal direction. Hardware.   The convex serration has a side length of 0.1 mm or more and 0.3 mm or less, a longitudinal interval of 0.2 mm or more and 2 mm or less, and is formed in two or three along the arc shape of the groove. The terminal fitting according to claim 7, wherein the terminal fitting is provided.   The terminal fitting according to any one of claims 1 to 8, wherein the conductor wire is made of aluminum or an aluminum alloy. The terminal fitting according to any one of claims 1 to 9, wherein the entire terminal fitting is made of brass or phosphor bronze.   The terminal metal fitting as described in any one of Claim 1 to 10 is crimped | bonded to the terminal part of the covered electric wire, The covered electric wire with a terminal metal fitting characterized by the above-mentioned.

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