Crimped terminal attached electric wire and method of crimping crimped terminal to electric wire

A crimped terminal attached electric wire comprising an electric wire, which is made by covering a conductor part with an insulative coating, and a crimped terminal including a conductor crimping part which is crimped to the conductor part when a pair of crimping strip parts form a joint along the extending direction of the conductor part, wherein the conductor crimping part is swelled in a direction perpendicular to the extending direction of the conductor part, and is formed into a barrel form while the joint is the only joint, when the conductor crimping part is crimped to the conductor part.

TECHNICAL FIELD

The present invention relates to a crimped terminal attached electric wire which has an electric wire, which is made by covering a conductor part with an insulative coating, and a crimped terminal including a conductor crimping part which is crimped to the conductor part, and a method of crimping the crimped terminal to the electric wire.

BACKGROUND ART

Traditionally, there is a crimped terminal attached electric wire which has an electric wire, which is made by covering a conductor part with an insulative coating, and a crimped terminal including a conductor crimping part which is crimped to the conductor part when a pair of crimping strip parts form a joint along the extending direction of the conductor part. In such a crimped terminal attached electric wire, the conductor crimping part of the crimped terminal, which becomes a part that is crimped to the conductor part, and the conductor part are expanded in the extending direction of the conductor part due to the load for crimping. Since the expanding amount of the conductor crimping part is different from that of the conductor part, when, for example, insulative or conductive material is applied to the crimping part to ensure the connection stability, it is necessary to stabilize the position of the conductor crimping part relative to the conductor part in the extending direction of the conductor part after the conductor crimping part has been crimped to the conductor part.

To solve such a problem, a crimped terminal attached electric wire is proposed, for example, in a patent document 1 in which wire barrel strips (conductor crimping parts) are separately formed in the extending direction of the conductor part to control the expanding of the wire barrel strips.

In the crimped terminal attached electric wire described in the patent document 1, a strong crimping part, which is crimped with a high pressure to be highly compressed, is formed at the front side of a cut portion among the wire barrel strips by a first step, and a weak crimping part, which is crimped with a low pressure to be lowly compressed, is formed at the back side of the cut portion among the wire barrel strips by a second step.

CITATION LIST

Patent Document

SUMMARY OF INVENTION

Technical Problem

However, in the crimped terminal attached electric wire described in the patent document 1, because the cut portion for separating the wire barrel strips is formed, the strength of the wire barrel strips is decreased, and, as a result, the connection stability of the crimped terminal and the conductor part might decrease.

The present invention is made in view of the above situation, and the object of the present invention is to provide a crimped terminal attached electric wire and a method of crimping a crimped terminal to an electric wire so that a decrease of the connection stability of the crimped terminal and the electric wire can be prevented.

Solution to Problem

It is therefore a first aspect of the invention to provide a crimped terminal attached electric wire comprising: an electric wire, which is made by covering a conductor part with an insulative coating; and a crimped terminal including a conductor crimping part which is crimped to the conductor part when a pair of crimping strip parts form a joint along the extending direction of the conductor part, wherein the conductor crimping part is swelled in a direction perpendicular to the extending direction of the conductor part, and is formed into a barrel form while the joint is the only joint, when the conductor crimping part is crimped to the conductor part.

It is a second aspect of the invention to provide a method of crimping a crimped terminal to an electric wire, the crimped terminal attached electric wire comprising: the electric wire, which is made by covering a conductor part with an insulative coating; and the crimped terminal including a conductor crimping part which is crimped to the conductor part when a pair of crimping strip parts form a joint along the extending direction of the conductor part, including a crimping step in which the conductor crimping part is swelled in the direction perpendicular to the extending direction of the conductor part, and is crimped into a barrel form while the joint is the only joint.

It is a third aspect of the invention to provide a method of crimping the crimped terminal to the electric wire, wherein the crimping in the crimping step is the only crimping to complete the conductor crimping part crimped to the conductor part.

Advantageous Effects of the Invention

For the crimped terminal attached electric wire according to the first aspect of the present invention, when the conductor crimping part is crimped to the conductor part, the conductor crimping part is swelled in the direction perpendicular to the extending direction of the conductor part, and is formed into a barrel form while the joint is the only joint. Therefore, since the conductor crimping part and the conductor part are expanded in the direction perpendicular to the extending direction of the conductor part, the expanding quantities of the conductor crimping part and the conductor part in the extending direction are prevented, and the position of the conductor crimping part relative to the conductor part in the extending direction of the conductor part is stabilized. Besides, since the necessary portion where the joint is formed is limited to a minimum, a decrease of the strength is prevented. As a result, a decrease of the connection stability of the crimped terminal and the electric wire can be prevented.

The method of crimping the crimped terminal to the electric wire according to the second aspect of the present invention includes a crimping step in which the conductor crimping part is swelled in the direction perpendicular to the extending direction of the conductor part, and is crimped into a barrel form while the joint is the only joint. Therefore, since the conductor crimping part and the conductor part are expanded in the direction perpendicular to the extending direction of the conductor part, the expanding quantities of the conductor crimping part and the conductor part in the extending direction are prevented, and the position of the conductor crimping part relative to the conductor part in the extending direction of the conductor part is stabilized. Besides, since the necessary portion where the joint is formed is limited to a minimum, a decrease of the strength is prevented. As a result, a decrease of the connection stability of the crimped terminal and the electric wire can be prevented.

With the method of crimping the crimped terminal to the electric wire according to the third aspect of the present invention, since the crimping of the conductor crimping part is completed by one crimping when the conductor crimping part is crimped to the conductor part, the number of crimping times can be prevented from increasing. Besides, the management of the molds becomes easy because the number of the molds for crimping can be prevented from increasing. Further, the variation of the shape after the conductor crimping part has been crimped can be reduced.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments of crimped terminal attached electric wires and methods of crimping a crimped terminal to an electric wire according to the present invention will be described in detail with reference to the figures as follows.

FIG. 1is a top view of a crimped terminal attached electric wire1according to an embodiment of the present invention.FIG. 2is a top view which shows a section of part of the crimped terminal attached electric wire1shown in1.

The crimped terminal attached electric wire1according to the embodiment of the present invention has an electric wire10which is made by covering a conductor part11with an insulative coating12, and a crimped terminal20including a conductor crimping part22which is crimped to the conductor part11so that a pair of crimped strip parts22bform a joint22calong the extending direction of the conductor part11.

The electric wire10is made by covering the conductor part11, which is made by bundling a plurality of metal strands10a, with the insulative coating12.

The metal strands10aare made of, for example, aluminum material, and a plurality of the metal strands10aare bundled to function as the conductor part11.

The insulative coating12is made of insulative materials such as synthetic resin, and protects the conductor part11so that the conductor part11can be insulated by being formed to cover the circumference of the conductor part11.

The electric wire10is so formed that the crimped terminal20is connected to the conductor part11that is exposed by removing the insulative coating12at a terminal part10aof the electric wire10.

The crimped terminal20is formed into a predetermined shape by forging with metal molds and bending a flat plate of, for example, copper alloy into the predetermined shape. The crimped terminal20is a female terminal, and has a mating connecting part21which becomes a part connecting with a mating connecting point not shown in the figure, a conductor crimping part22which is crimped to the exposed conductor part11, and an insulative coating crimping part23which is crimped to the insulative coating12of the electric wire10.

The mating connecting part21has a box-like shape, and an elastic contact strip not shown in the figure is formed inside the mating connecting part21. The mating connecting part21is a part that is connected to a male terminal, which is not shown in the figure and becomes a mating connecting terminal, through the elastic contact strip.

The conductor crimping part22is formed between the mating connecting part21and the insulative coating crimping part23, and is a part where the crimped terminal20and the conductor part11are connected. The conductor crimping part22has a base22aincluding a wall that forms a bottom surface, and the pair of crimped strip parts22bwhich are formed when two edges of the base22aare raised into a strip form. The pair of crimped strip parts22bare crimped to the conductor part11by being bent inwardly by using a jig for crimping.

An upper mold30to be described below and referred to as a crimper and a lower mold40referred to as an anvil are used as the jig for crimping, and the conductor crimping part22is crimped to the conductor part11when the conductor crimping part22is crushed by the upper mold30and the lower mold40into a predetermined shape.

When the conductor crimping part22is crimped to the conductor part11, as shown with the arrows D inFIG. 1, the conductor crimping part22is swelled in a direction perpendicular to the extending direction of the conductor part11, and is formed into a barrel form while the joint22cis the only joint. That is, the conductor crimping part22is formed to be expanded in the direction perpendicular to the extending direction of the conductor part11.

The conductor part11crimped by the conductor crimping part22follows the inside shape of the conductor crimping part22, and is expanded in the direction perpendicular to the extending direction.

That is, since both the conductor crimping part22and the conductor part11are expanded in the direction perpendicular to the extending direction of the conductor part11, the expanding amounts in the extending direction of the conductor part11are controlled.

Besides, since the necessary portion where the joint is formed is limited to a minimum, a decrease of the strength of the conductor crimping part22is prevented.

The insulative coating crimping part23forms an end opposite to the mating connecting part21of the crimped terminal20, and is a part which holds the electric wire10by being crimped to the insulative coating12. The insulative coating crimping part23has a base23awhich follows the base22aof the conductor crimping part22, and a pair of crimping strip parts23bwhich are formed when two edges of the base23aare raised. The pair of crimping strip parts23bare crimped to the insulative coating12by being bent inwardly by using a jig for crimping not shown in the figure.

Next, steps of crimping the crimped terminal20to the electric wire10are described by usingFIGS. 3A to 6.FIGS. 3A to 3Care figures showing a flow of steps of crimping the crimped terminal20to the electric wire10.FIGS. 4A and 4Bare figures showing the flow of the steps of crimping inFIG. 3by using a section perpendicular to the extending direction of the conductor part11.FIG. 5is a perspective view of the upper mold30shown inFIGS. 3A and 3B.FIG. 6is a figure, which is viewed from below, of the upper mold30shown inFIG. 5.FIG. 7is a perspective view which shows an upper mold which is a variation of the upper mold shown inFIG. 5.FIG. 8is a figure, which is viewed from below, of the upper mold30shown inFIG. 7.

The operation of crimping the crimped terminal20to the electric wire10is performed by an operator who operates the upper mold30and the lower mold40by using, for example, a crimping device not shown in the figure.

Since the steps of crimping the crimped terminal20to the insulative coating12are typical crimping steps, the related explanation is omitted here.

First, the operator sets the crimped terminal20on the lower mold40when the conductor part11is carried on the bottom wall22aof the crimped terminal20, and makes the upper mold30drop from above the conductor crimping part22(refer toFIGS. 3A and 4A).

Below, the upper mold30and the lower mold40are described in detail.

As shown inFIGS. 5 and 6, the upper mold30has an arch shape which opens towards the lower mold40, and the arch inside surface becomes guiding surfaces32for crushing the conductor crimping part22into a barrel form. The guiding surfaces32are so formed that the distance between a pair of arch foot parts31is enlarged in some areas. More specifically, as shown inFIG. 6, the guiding surface32has variable-distance guiding surface parts32awhich are slanted so that the distance between the arch foot parts31increases gradually from two end surfaces30aof the upper mold30towards the inside, and a uniform-distance guiding surface32bwhich is so provided that an area of a certain width in which the distance between the arch foot parts31becomes maximum is formed between the variable-distance guiding surface parts32abetween the two end surfaces30a.

As shown inFIGS. 3A and 4A, the lower mold40has a generally cubical shape, and the top surface of the lower mold40on which the conductor crimping part22is carried becomes a curved guiding surface41for crushing the conductor crimping part22into a barrel form.

As shown inFIGS. 7 and 8, it is also possible that the upper mold30does not have the uniform-distance guiding surface32b.

As such an upper mold30is dropped towards the lower mold40to sandwich the conductor part11, the pair of crimping strip parts22bof the conductor crimping parts22are bent to be slid on the guiding surfaces32, the circumference of the conductor part11is enclosed into a barrel form and the joint22cis formed along the extending direction of the conductor part11.

Then, when the operator makes the upper mold30drop to the lowest position in the movement for crimping, the crimping is completed (refer toFIGS. 3B,3C and4B). Thereby, the conductor crimping part22is molded into a barrel form and is crimped to the conductor part11. Thereby, the expansions of the conductor crimping part22and the conductor part11in the extending direction of conductor part11are converted into the expansions in the direction perpendicular to the extending direction of the conductor part11. Since there is only one joint22cin the conductor crimping part22, the crimping of the conductor crimping part22is completed by one crimping.

For the crimped terminal attached electric wire1according to the embodiment of the present invention, when the conductor crimping part22is crimped to the conductor part11, the conductor crimping part22is swelled in the direction perpendicular to the extending direction of the conductor part11, and is formed into a barrel form while the joint22cis the only joint. Therefore, since the conductor crimping part22and the conductor part11are expanded in the direction perpendicular to the extending direction of the conductor part11, the expanding quantities of the conductor crimping part22and the conductor part11in the extending direction are prevented, and the position of the conductor crimping part22relative to the conductor part11in the extending direction of the conductor part11is stabilized. Besides, since the necessary portion where the joint22cis formed is limited to a minimum, a decrease of the strength is prevented. As a result, a decrease of the connection stability of the crimped terminal20and the electric wire10can be prevented.

The method of crimping the crimped terminal to the electric wire according to the embodiment of the present invention includes a crimping step in which the conductor crimping part22is crimped to the conductor part11into a barrel form which assumes the axis of the conductor part11as an axis. Therefore, since the conductor crimping part22and the conductor part11are expanded in the direction perpendicular to the extending direction of the conductor part11, the expanding quantities of the conductor crimping part22and the conductor part11in the extending direction are prevented, and the position of the conductor crimping part22relative to the conductor part11in the extending direction of the conductor part11is stabilized. As a result, the connection stability of the crimped terminal and the electric wire can be improved.

With the method of crimping the crimped terminal to the electric wire according to the embodiment of the present invention, since the crimping of the conductor crimping part22is completed by one crimping when the conductor crimping part22is crimped to the conductor part11, the number of crimping times can be prevented from increasing. Besides, the management of the molds becomes easy because the number of the molds for crimping can be prevented from increasing. Further, the variation of the shape after the conductor crimping part22has been crimped can be reduced.

It is exemplified in the crimped terminal attached electric wire1and the method of crimping the crimped terminal to the electric wire according to the embodiment of the present invention that the conductor part11is made by bundling a plurality of metal strands11a, but the invention is not limited to this and it is also possible that the conductor part11is made of a single core strand.

It is exemplified in the crimped terminal attached electric wire1and the method of crimping the crimped terminal to the electric wire according to the embodiment of the present invention that the crimped terminal20is a female terminal, but the invention is not limited to this and it is also possible to use other crimped terminals as long as the crimped terminal is crimped to the conductor part of the electric wire. For example, a male terminal may be used.

It is exemplified in the crimped terminal attached electric wire1and the method of crimping the crimped terminal to the electric wire according to the embodiment of the present invention that the insulative coating crimping part23is included, but the invention is not limited to this and it is also possible that the insulative coating crimping part23is not included.

It is exemplified in the crimped terminal attached electric wire1and the method of crimping the crimped terminal to the electric wire according to the embodiment of the present invention that the conductor crimping part22is swelled in the directions perpendicular to the extending direction of the conductor part11, and is formed into a barrel form in all directions perpendicular to the extending direction. However, the conductor crimping part22may not be swelled. One example is shown inFIG. 9. In this example, the conductor crimping part22is formed flatly and having a cylindrical shape. In this case, since the necessary portion where the joint is formed is limited to a minimum, a decrease of the strength is prevented.

The invention accomplished by the inventor is described in detail based on the above embodiment of the invention, but the present invention is not limited to the above embodiment and can be modified in various ways without departing from the spirit of the invention.