JP2010198789A - Terminal structure of crimp terminal - Google Patents

Abstract

An object of the present invention is to crimp a wire by improving the electrical connectivity and mechanical connectivity of a crimp terminal.
A crimp terminal includes, for example, a connecting portion, a crimp barrel portion, and a holding barrel portion, and an aluminum electric wire has a structure in which a core wire is covered with a coating. The crimping barrel portion 12 includes a pair of sandwiching pieces 16, 16, and serrations 17 including a plurality of groove portions 18 are formed on the inner surface. In this serration 17, the total surface area (groove area) of the side surfaces b and c excluding the bottom surface a of the plurality of groove portions 18 constituting the serration 17 is at least twice the cross-sectional area of the surface perpendicular to the axial direction of the core wire 21. Is formed. Thereby, it becomes possible to improve the electrical connectivity and mechanical connectivity of the crimp terminal 10 with the aluminum electric wire 20.
[Selection] Figure 3

Description

  The present invention relates to a terminal structure of a crimp terminal that is crimp-connected to an electric wire having a core wire made of a conductive material.

  Conventionally, as a crimping terminal to be crimped and connected to an electric wire, a terminal crimping structure and a terminal crimping method to an aluminum electric wire, and a manufacturing method of an aluminum electric wire with a terminal (for example, Patent Document 1 (pages 6-9, 1- (See Fig. 5). The terminal crimping structure is a structure in which a terminal is crimped to an aluminum electric wire composed of a large number of stranded wires and a covering portion covering the stranded wires, and has a wire barrel in which the terminal is crimped to a conductor portion of the aluminum electric wire.

When the cross-sectional area of the aluminum wire conductor portion to be crimped is less than 1.5 mm ² , the compression rate of the aluminum wire conductor portion by the wire barrel is the aluminum wire conductor cross-sectional area of the crimped portion before being crimped. The ratio divided by the sectional area is assumed to be in the range of 50 to 70%.

  Further, there are known aluminum crimped wire crimp terminals and terminal structures of aluminum twisted wires to which the crimp terminals are connected (for example, see Patent Document 2 (page 4-6, Fig. 1-4)). This aluminum stranded wire crimping terminal is provided with serrations on the inner surface of the crimping portion, and the ratio of the depth of the groove constituting the serration to the diameter of the aluminum strand constituting the aluminum stranded wire is 0.33 or more. The number is 3 or more. Moreover, the aluminum strand wire is comprised so that the ratio of the cross-sectional area after crimping and the cross-sectional area before crimping may be 0.7-0.95 in the terminal.

JP 2005-174896 A JP 2007-173215 A

  However, in the terminal crimping structure disclosed in Patent Document 1 described above, the compression rate is reduced to 50% to 70% compared to 75% to 95% in the case of copper in order to maintain electrical characteristics. (Ie, high compression) For this reason, in the aluminum electric wire and aluminum alloy electric wire which use aluminum whose inferior tensile strength is lower than copper, there exists a problem that there exists a possibility that it may fracture | rupture by a use condition etc.

  Moreover, in the crimp terminal disclosed in Patent Document 2 described above, when applied to a thin terminal plate, the ratio of the depth of the serration groove is increased if the wire diameter of the electric wire is large. I can't. For this reason, there is a problem that application to a thin plate terminal is difficult and electrical connectivity may be unstable.

  Furthermore, if the number of serration grooves is increased in order to improve electrical connectivity (including mechanical connectivity) in this case, it may be sufficient depending on the length of the wire barrel in the axial direction of the wire barrel in which the grooves are arranged. It is not possible to set a large number. On the other hand, if the length dimension is sufficiently large, there is a problem that there is a possibility that a problem such as the terminal popping out of the connector housing may occur depending on the size of the connector housing that accommodates the terminal.

  An object of the present invention is to provide a terminal structure of a crimp terminal that can be crimped to an electric wire by improving the electrical and mechanical connectivity of the crimp terminal in order to eliminate the above-described problems caused by the prior art. And

  In order to solve the above-described problems and achieve the object, a terminal structure of a crimp terminal according to the present invention is a terminal structure of a crimp terminal to be crimped and connected to an electric wire having a core wire made of a conductive material, Each of the terminals includes a pair of clamping pieces that are crimped to the core wire by being bent inward in the opposing direction, and has at least a crimp barrel portion in which a cross section in a direction orthogonal to the axial direction of the core wire is formed in a U shape. A plurality of recesses constituting serrations on the inner surface of the crimping barrel portion, and a total surface area of a portion excluding the bottom surfaces of the plurality of recesses is perpendicular to the axial direction of the core wire to be crimped to the crimping barrel portion It is formed so that it may become 2 times or more of the cross-sectional area.

  The crimp terminal is made of, for example, a conductive material different from the conductive material constituting the core wire.

  The conductive material constituting the core wire is, for example, any one of aluminum, an aluminum alloy, copper, and a copper alloy, and the crimp terminal is made of, for example, copper or a copper alloy.

  The crimp terminal has a structure in which tin plating is formed on the surface of, for example, copper or a copper alloy.

  The crimp barrel portion is formed by, for example, pressing.

  The crimp terminal further includes, for example, a connection portion connected to the connection partner connection terminal, and a holding barrel portion that crimps and holds the electric wire together with the coating.

  ADVANTAGE OF THE INVENTION According to this invention, the terminal structure of the crimp terminal which can be crimped | bonded to an electric wire can be provided by improving the electrical connectivity and mechanical connectivity of a crimp terminal.

It is a side view for demonstrating the example of the crimp terminal and electric wire to which the terminal structure of the crimp terminal concerning one Embodiment of this invention is applied. It is a figure which shows the A-A 'cross section of FIG. It is explanatory drawing for demonstrating the example of a part of crimp terminal concerning one Embodiment of this invention. It is explanatory drawing for demonstrating the other example of a part of crimp terminal concerning one Embodiment of this invention. It is explanatory drawing for demonstrating the relationship between the serration groove part area and connection resistance in the thermal shock test of the crimp terminal concerning one Embodiment of this invention.

  Hereinafter, preferred embodiments of a terminal structure of a crimp terminal according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a side view for explaining an example of a crimp terminal and an electric wire to which a terminal structure of a crimp terminal according to an embodiment of the present invention is applied, and FIG. 2 is a diagram showing a cross section taken along line AA ′ of FIG. is there. 3 is an explanatory diagram for explaining an example of a part of a crimp terminal according to an embodiment of the present invention, and FIG. 4 is another example of a part of the crimp terminal according to an embodiment of the present invention. It is explanatory drawing for demonstrating.

  As shown in FIG. 1, the crimp terminal 10 having the terminal structure according to the present embodiment includes, for example, punching (pressing) / bending (bending) a metal (iron, copper, copper alloy, etc.) base material, respectively. It has at least a crimping barrel portion 12 including a pair of sandwiching pieces 16 and 16 described later, which are crimped to the core wire 21 by being bent inward in the facing direction. In this example, the crimp terminal 10 is formed by processing the above-described metal base material made of copper or copper alloy. For example, the surface of the metal base material that is tin-plated may be used. .

  Further, the crimp terminal 10 has a connection part 11 fitted and connected to a connection counterpart connection terminal (not shown) on the distal end side, the crimp barrel part 12 on the proximal side of the connection part 11, and A holding barrel portion 13 is provided on the proximal end side to hold an aluminum electric wire (hereinafter referred to as “aluminum electric wire”) 20 together with a coating 22 and press-fit.

  The aluminum electric wire 20 has a structure in which the core wire 21 is made of a conductor (conductive material) such as aluminum or an aluminum alloy, and the core wire 21 is covered with a coating 22 made of an insulating material. The aluminum electric wire 20 may be, for example, one in which a core wire 21 made of a single-wire aluminum conductor is covered with a coating 22, or one in which a core wire 21 made of a stranded wire formed by twisting a plurality of aluminum conductors is covered with a coating 22. But you can. In this example, what has the core wire 21 which consists of these electrically conductive materials is named generically as the aluminum electric wire 20. FIG. Furthermore, as the electric wire to be crimped to the crimp terminal 10, in addition to the aluminum electric wire 20, a core wire 21 made of copper or a copper alloy may be covered with a coating 22.

  Here, the locking piece 14 and the locking hole 15 formed in the connection portion 11 of the crimp terminal 10 are, for example, an engagement formed in a terminal receiving hole of a connector housing (not shown) into which the crimp terminal 10 is inserted. It is used to engage with the locking recesses and locking projections to position and attach and fix the crimp terminal 10 in the terminal receiving hole, and is formed as necessary.

  The crimping barrel portion 12 of the crimping terminal 10 is composed of a pair of sandwiching pieces 16 and 16 (see, for example, FIG. 2) which are erected substantially in parallel when not crimped. After the core wire 21 is placed, the core wire 21 is crimped to the core wire 21 by bending each of them inward in the opposite direction.

  The crimp barrel portion 12 includes a plurality of recess portions 18 that form serrations (saw-toothed jagged portions) 17 (see FIG. 3) on the inner surface surrounded by the pair of sandwiching pieces 16, 16. Is formed so as to intersect with the axial direction of the core wire 21 at the time of development as shown in FIG. In this example, three groove portions 18 are arranged side by side so that the axial direction of the core wire 21 is along the width direction intersecting the length direction thereof. FIG. 3A shows the crimping barrel portion 12 in an unfolded state.

  Each of the groove portions 18 has a predetermined length L, a width H, and a depth D, and is formed in a shape in which the bottom surface a and the side surfaces b and c intersect at right angles. The total surface area (hereinafter referred to as “groove area”) of the portion excluding the bottom surface a of the groove portion 18 (hereinafter referred to as “groove portion area”) is the axis of the core wire 21 to be crimped in the crimp barrel portion 12. It is preset and formed so as to be at least twice the cross-sectional area of the surface orthogonal to the direction. The groove portion 18 constituting the serration 17 is formed in the crimp barrel portion 12 by pressing or the like.

  Thus, by making the groove part area of the groove part 18 constituting the serration 17 more than twice the cross-sectional area of the surface orthogonal to the axial direction of the core wire 21, particularly from the core wire 21 of the aluminum electric wire 20 and copper or the like. The following effects are also obtained when crimping with a combination of materials having greatly different linear expansion coefficients, such as the crimp terminal 10. That is, according to the terminal structure of this example, the contact area between the core wire 21 and the crimping barrel portion 12 that is generated due to a temperature change and is considered to be a cause of a decrease in electrical connectivity, while increasing the contact area, The play can be effectively suppressed. Therefore, the electrical connectivity and mechanical connectivity of the crimp terminal 10 can be improved.

  And since the groove part area of the some groove part 18 which comprises the serration 17 can be arbitrarily set with components, such as the length L of each groove part 18, width H, depth D, number, and its shape, these The groove area determined by the above component may be at least twice (preferably at least three times) the cross-sectional area of the plane orthogonal to the axial direction of the core wire 21.

  For this reason, the shape of the recessed part which comprises this serration 17 may be as follows, when it sees from upper direction, for example, when the crimping | compression-bonding barrel part 12 is made into the unfolded state. That is, as shown in FIG. 4 (a), even if the serrations 17 are configured by arranging a plurality of rectangular depressions 31 in a lattice shape, as shown in FIG. 4 (b), a plurality of rhombus depressions. Serrations may be configured by arranging the concave portions 32 in a staggered pattern, and the serrations may be configured by a plurality of circular concave portions 33 as shown in FIG.

  Further, as shown in FIG. 4D, as described above, a plurality of groove-like recesses 34 having a width H narrower than the groove 18 shown in FIG. Even if it is configured by arranging them side by side along the axial direction of the core wire 21, it may be configured by a plurality of groove-like recesses 35 that are continuous in a lattice shape as shown in FIG. As shown to (f), you may be comprised by the groove-shaped recessed part 36 which continues in a several zigzag form.

  Further, as shown in FIG. 4 (g), even if the plurality of concave portions 37 bent into a crank shape are arranged side by side along the axial direction of the core wire 21 as described above, And as shown to FIG. 4 (i), you may comprise by arrange | positioning the recessed parts 38 and 39 bent in a wave shape in parallel along the axial direction of the core wire 21 as mentioned above.

  Further, taking FIG. 4 (a) and FIG. 4 (b) as examples, even if the formation conditions (width H, interval, number, etc.) of the recesses 31, 32 are the same, the present application In the human evaluation test, the connection resistance of the concave portion 31 is larger than the connection resistance of the concave portion 32, and therefore, the electrical connection is improved in the crimp terminal 10 having the serration constituted by the concave portion 32. There was found.

  That is, when comparing the components along the width direction when the crimping barrel portion 12 is expanded perpendicular to the axial direction of the core wires 21, the component of the recess 32 is larger than that of the recess 31. For this reason, if the serrations 17 are configured in consideration of the direction and shape of the grooves 18 constituting the serrations 17, it is possible to obtain an effect of further improving electrical connectivity.

  Thus, according to the crimp terminal 10 of the present example, the groove area of the plurality of recesses constituting the serration 17 is larger than the cross-sectional area of the surface orthogonal to the axial direction of the core wire 21. For this reason, since electrical connection property and mechanical connection property can be improved without reducing the compression rate (that is, high compression) as in the prior art, the risk of breakage of the core wire 21 is minimized. It becomes possible.

  Further, since the groove area of the plurality of recesses constituting the serration 17 may be made larger than the cross-sectional area of the surface orthogonal to the axial direction of the core wire 21, for example, in the example shown in FIG. It is possible to appropriately cope with various core wires 21 and the like only by changing the component such as the length L as a component other than the number and the component other than the number.

As shown in FIG. 5, the applicant of the present invention is an environmental test using a sample in which the crimp terminal 10 configured as described above is crimped to the core wire 21 of the aluminum electric wire 20 at a compression rate of about 70% to 80%. A thermal shock test (thermal shock test) was performed. In this test, as the aluminum electric wire 20 crimped to the crimp terminal 10, a cross-sectional area of the surface perpendicular to the axial direction of the core wire 21 is 0.75 mm ² , and the temperature on the high temperature side is 120 ° C. for 15 minutes. While heating, the temperature on the low temperature side was set to −30 ° C. and cooling for 15 minutes was repeated 3000 cycles.

According to this, when the groove area of the concave portion constituting the serration 17 is about 1.2 mm ² , the allowable connection resistance 3 mΩ is greatly increased and decreased, resulting in variations in the connection resistance. I understand that However, the groove area is 1.5 mm ^two (i.e., the cross-sectional twice the area) about or 2.25 mm ² (i.e., three times the cross-sectional area) be about, the connection resistance is below the permissible connection resistance 3mΩ Therefore, it can be seen that the electrical connectivity is improved as compared with the case where the groove area is about 1.2 mm ² .

Furthermore, it can be said that the electrical connectivity is stable when the groove area is about 4.0 mm ² . As a result, in the terminal structure of the crimp terminal 10 of this example, the groove area of the concave portion constituting the serration 17 is set to be twice or more the cross-sectional area of the surface orthogonal to the axial direction of the core wire 21 of the aluminum electric wire 20; As a result, it is possible to improve the electrical connectivity and mechanical connectivity of the crimp terminal 10 with the aluminum electric wire 20 and perform crimping.

DESCRIPTION OF SYMBOLS 10 Crimp terminal 11 Connection part 12 Crimp barrel part 13 Holding barrel part 14 Locking piece 15 Locking hole 16 Clamping piece 17 Serration 18 Groove part 20 Aluminum electric wire 21 Core wire 22 Covering 31-39 Recessed part

Claims (6)

A terminal structure of a crimp terminal to be crimped and connected to an electric wire having a core wire made of a conductive material,
The crimp terminal includes a pair of clamping pieces that are crimped to the core wire by being bent inward in the opposing direction, and a crimp barrel portion having a U-shaped cross section in a direction perpendicular to the axial direction of the core wire. Have at least
A plurality of recesses constituting serrations are formed on the inner surface of the crimping barrel portion, and the total surface area of the portions excluding the bottom surfaces of the plurality of recesses is cut off in a plane perpendicular to the axial direction of the core wire to be crimped to the crimping barrel portion. A terminal structure of a crimp terminal, wherein the terminal structure is formed so as to be at least twice the area. The terminal structure of the crimp terminal according to claim 1, wherein the crimp terminal is made of a conductive material different from a conductive material constituting the core wire. The conductive material constituting the core wire is any one of aluminum, aluminum alloy, copper, and copper alloy,
The terminal structure of the crimp terminal according to claim 1, wherein the crimp terminal is made of copper or a copper alloy. The terminal structure of a crimp terminal according to claim 3, wherein the crimp terminal has a structure in which tin plating is formed on a surface of copper or a copper alloy. The terminal structure of the crimp terminal according to claim 1, wherein the crimp barrel portion is formed by press working. The said crimp terminal is further provided with the connection part connected with a connection other party connection terminal, and the holding | maintenance barrel part which crimps and hold | maintains the said electric wire with a coating | cover, Crimping of any one of Claims 1-5 characterized by the above-mentioned. Terminal structure of the terminal.

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