JP2005327690A - Terminal crimping structure and terminal crimping method to aluminum cable and manufacturing method of aluminum cable with terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a terminal crimping structure and a terminal crimping method to an aluminum cable in which when crimping a terminal to an aluminum cable, the electrical property of the connection part can be maintained regardless of changes in the environment, and a manufacturing method of an aluminum cable with the terminal. <P>SOLUTION: This is the terminal crimping structure to an aluminum cable in which a terminal 1 is crimped to an aluminum cable 40 consisting of a large number of strands and a covering part for covering the strands. The terminal 1 is a closed barrel type terminal and has a wire barrel 21 to be crimped to the conductor part of the aluminum cable, and the compression rate of the aluminum cable conductor part 41 in the conduction secured region with the aluminum cable of the wire barrel 21 is in the range of 50-70% as a ratio of aluminum cable conductor part cross-section of the crimping portion/aluminum cable conductor part cross-section before crimping. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a terminal that is used by being crimped to an aluminum electric wire, and relates to a terminal crimping structure to an aluminum electric wire, a terminal crimping method, and a method for manufacturing an aluminum electric wire with a terminal.

  Conventionally, a copper wire is generally used as a wire harness routed in an automobile, and an aluminum wire having poor properties (physical properties) such as conductivity and strength has not been used so much. However, in recent years, there has been an increasing demand for the use of aluminum wires in view of weight reduction and recyclability of vehicles. On the other hand, an electrical connector is generally used for connecting wire harnesses to each other or to an in-vehicle device and a wire harness. Such an electrical connector is composed of connector housings that are fitted to each other and a plurality of crimp terminals that are inserted and fitted into these connector housings and crimped and connected to wires of a wire harness.

  There are generally two types of crimping portions of terminal fittings that constitute the crimping terminal: an open barrel and a closed barrel. The crimping shape is selected at each design stage depending on the type of electric wire used, the electric wire size, the wire configuration, the difference in material, and the like. For example, an open barrel type crimp terminal is generally used when the wire diameter of the wire is thin, and a closed barrel type crimp terminal is used when the wire diameter of the wire is large. Further, the compression ratio (also referred to as the area reduction ratio, hereinafter simply referred to as “compression ratio”) defined by the ratio of the cross-sectional area of the wire conductor portion of the crimped portion / the cross-sectional area of the wire conductor portion before the crimping is a stable region of contact resistance. It is determined from the viewpoints of being inside, no disconnection due to vibration, and having a sufficient electric wire fixing force.

  The compression ratio of the cross section of the wire conductor at the time of terminal crimping is specified and controlled within a range of 75% to 95% although it varies slightly depending on the manufacturer and the wire size (for example, see Patent Document 1).

Utility Model Registration No. 3005065 (page 5-6, FIG. 3)

  In the conventional terminal crimping method, the terminal is crimped to the wire conductor portion of the copper wire at the compression rate described above. Even if the terminal is crimped to the copper wire at such a compression rate, the terminal can be connected to the copper wire without any problem in terms of its function due to the mechanical and electrical properties of the copper wire. It was usable without any inconvenience.

  However, an aluminum electric wire has a lower fusing temperature than a copper electric wire, and each stranded wire constituting the electric wire tends to form an oxide film. Therefore, current flows only through a specific stranded wire, and concentrated resistance is likely to be generated, and there is a concern about occurrence of fusing or poor conduction due to such concentrated resistance.

  When an aluminum wire is actually crimped to a terminal under the same conditions as a copper wire, the resistance of the crimped portion of the terminal rises due to changes in the environment, such as high or low temperatures, causing problems in conduction, and the terminal and wire A good electrical connection state cannot be maintained between. For this reason, it is not appropriate to perform crimping at the compression rate described above for the terminal crimping structure to the aluminum electric wire.

  The present invention provides a terminal crimping structure to an aluminum wire, a method for crimping the terminal, and a method for manufacturing the aluminum wire with a terminal, which can maintain the electrical characteristics of the connection portion regardless of environmental changes when crimping the terminal to the aluminum wire. The purpose is to do.

  In order to solve the above-mentioned problem, the terminal crimping structure to the aluminum electric wire according to the present invention is a terminal crimping to the aluminum electric wire that crimps the terminal to the aluminum electric wire composed of a large number of stranded wires and a covering portion covering the stranded wires. It is a structure, the terminal is a closed barrel type terminal and has a wire barrel that is crimped to the conductor part of the aluminum electric wire, and the compression ratio of the aluminum electric wire conductor part in the conduction securing region with the aluminum electric wire of the wire barrel is The ratio of the cross-sectional area of the aluminum wire conductor portion of the crimped portion / the cross-sectional area of the aluminum wire conductor portion before the crimping is in the range of 50 to 70%.

  Moreover, the terminal crimping method to the aluminum electric wire of Claim 2 of this invention is a terminal crimping method to the aluminum electric wire which crimps | bonds a terminal to the aluminum electric wire which consists of a coating | coated part which coat | covers many said stranded wires and the said stranded wire. In addition to preparing an aluminum wire, a terminal that has a closed barrel type terminal and a wire barrel that is crimped to the conductor portion of the aluminum wire is prepared, and the aluminum wire in the area where the electrical connection between the wire barrel and the aluminum wire is secured Crimping the terminal to the aluminum wire so that the compression ratio of the conductor is within the range of 50 to 70% by the ratio of the cross-sectional area of the aluminum wire conductor in the crimped portion / the cross-sectional area of the aluminum wire conductor before crimping. It is a feature.

  By controlling the compression rate of the aluminum wire at the upper limit as described above, there is no increase in resistance of the aluminum wire with terminals in the environmental test in which the device under test is exposed to high or low temperatures, and stable electrical connection Can be maintained.

  Moreover, the crimping | compression-bonding strength of an aluminum electric wire does not fall remarkably by managing the compression rate of an aluminum electric wire by the above lower limits. Therefore, mechanical damage such as wire breakage in the aluminum wire crimping portion does not occur.

  Moreover, the manufacturing method of the aluminum electric wire with a terminal of Claim 3 of this invention manufactures an aluminum electric wire with a terminal by crimping | bonding a terminal to the aluminum electric wire which consists of a coating | coated part which coat | covers many said stranded wires and the said stranded wire. A method of manufacturing an aluminum electric wire with a terminal, in which an aluminum electric wire is prepared, and a terminal having a wire barrel that is a closed barrel type terminal and is crimped to a conductor portion of the aluminum electric wire is prepared. Terminals so that the compression ratio of the aluminum wire conductor portion in the conduction securing region is within the range of 50 to 70% in the ratio of the cross-sectional area of the aluminum wire conductor portion of the crimped portion / the cross-sectional area of the aluminum wire conductor portion before the crimping. This is characterized in that the aluminum wire with terminal is manufactured by crimping the wire to the aluminum wire.

  By manufacturing such an aluminum electric wire with a terminal, there is no increase in resistance in an environmental test that requires high or low temperature, and a stable electrical connection is maintained, and mechanical breakage such as electric wire breakage in the electric wire crimping part is performed. An aluminum electric wire with a terminal that does not cause damage can be obtained.

  As described above, in the present invention, the compression rate in the conduction securing region when connecting the aluminum wire conductor and the terminal is in the range of 50 to 70%, which is a compression rate that is not normally possible when crimping a conventional copper wire. By limiting to the above, it is possible to provide a terminal crimping structure to an aluminum electric wire that can maintain stable conduction between the terminal and the aluminum electric wire and has sufficient mechanical connection strength.

  Hereinafter, a terminal crimping structure and a crimping method for an aluminum electric wire according to an embodiment of the present invention and a method for producing an aluminum electric wire with a terminal will be described with reference to the drawings.

  The terminal 1 used for the terminal crimping structure to the aluminum electric wire concerning one Embodiment of this invention is comprised by the terminal connection part 10 and the wire barrel 20, as shown in FIG.1 and FIG.2. The wire barrel 20 forms a so-called closed barrel type terminal. As shown in FIG. 1, the terminal connection portion 10 has an elliptical ring shape in a top view, and the wire barrel 20 is a deformed cylindrical body formed extending from the terminal connection portion 10, and its upper half is As shown in FIGS. 4A and 4B, it is configured to be compressed into a substantially W-shaped cross-sectional shape when viewed from the end. Further, the wire barrel 20 has a shallow and recessed holding barrel region 21 for holding the aluminum wire conductor portion, and a deeply recessed conduction barrel region (conduction securing region) 22 for conducting the aluminum wire conductor portion 41 and the terminal connection portion 10. have.

  The terminal 1 is crimped to the aluminum electric wire 40 by the process shown in FIG. Hereinafter, it demonstrates in order of a process. First, as shown in FIG. 3A, a base 80 having a semicircular groove shape in the end view of the wire barrel 20 formed of a cylindrical portion of the aluminum electric wire crimp terminal 1 (see FIG. 3B). Secure to. In the state shown in FIG. 3 (a), the wire barrel 20 has an upper portion 20a joined in the longitudinal direction by silver brazing, and an aluminum electric wire conductor portion 41 made of a number of strands is inserted into a lower portion inside the wire barrel. ing.

  Next, the crimping jig 90 in which the crimping portions 91 and 92 that are semicircular when viewed from the end face protrude in parallel in the width direction is approached from above the wire barrel (see FIG. 3B). It should be noted that the crimping jigs 90 have different protrusion amounts of the crimping portions 91 and 92 in the longitudinal direction corresponding to the holding barrel region 21 and the conductive barrel region 22 of the wire barrel to be crimped. That is, the crimping portions 91 and 92 corresponding to the holding barrel region 21 of the terminal 1 are formed with two semicircular crimping portions arranged side by side as viewed from the end with a small protruding amount, and are connected to the terminal 1 respectively. The crimping portions 91 and 92 corresponding to the conductive barrel region 22 are formed with two semicircular crimping portions with a large protrusion amount arranged side by side. Then, the crimping jig 90 is lowered toward the terminal side by an actuator (not shown) (see FIG. 3B). By this downward movement, the corresponding portions of the holding barrel region 21 and the conductive barrel region 22 are gradually crushed and recessed along the respective crimping grooves of the crimping portion of the crimping jig 90 (see FIG. 3C).

  Then, by further lowering the crimping jig 90, the crimping portions 91 and 92 are pushed into the wire barrel 20 (see FIG. 3C), and in the cross-sectional views of FIGS. 4A and 4B. As shown, the upper portion of the wire barrel 20 is plastically deformed into a substantially W shape in an end view, and the wire barrel 20 is crimped to the aluminum wire conductor portion 41 corresponding to this portion.

  In this manner, the upper portion of the wire barrel 20 is flattened, and a part of the wire barrel 20 is recessed by the crimping jig 90 so that the corresponding region of each barrel has a different depth. That is, as shown in FIG. 1, the holding barrel region 21 is formed with two shallow recesses arranged in the terminal width direction, and the conduction barrel region 22 has a deep recess with the holding barrel region 21. Two are formed side by side in the terminal width direction in succession to the recess. Further, the aluminum wire conductor portion is compressed at a low compression rate in the holding barrel region 21 corresponding to these recesses, and the aluminum wire conductor portion is compressed at a high compression rate in the conduction barrel region.

  The compression rate here is a percentage of the compression rate (area reduction) of the aluminum wire conductor part defined by the cross-sectional area of the aluminum wire conductor part of the crimping part / the cross-sectional area of the aluminum wire conductor part before crimping, and is high. The compression rate refers to a compression rate with a small specific value of the compression rate, and the low compression rate refers to a compression rate with a large specific value of the compression rate.

  As described above, when the terminal 1 is crimped to the aluminum wire conductor 41, the crimping jig 90 has a different protruding amount, so that the terminal holding barrel region 21 and the conducting barrel region 22 are crimped at different compression rates. To do. That is, in the holding barrel region 21, crimping is performed at the same compression rate as when crimping a terminal of a normal copper wire. On the other hand, in the conduction barrel region 22, the crimping is performed at a higher compression rate than that when crimping a terminal of a normal copper wire. Specifically, the compression ratio (area reduction) of the aluminum wire conductor portion defined by the cross-sectional area of the aluminum wire conductor portion where the conductive barrel region 22 is crimped / the cross-sectional area of the aluminum wire conductor portion before crimping is Although the specific compression rate differs slightly depending on the size, the terminal 1 is crimped to the aluminum electric wire 40 so as to be in the range of 50 to 70%. In addition, the range of this compression rate is in the range which cannot be present at the time of crimping | bonding a terminal to a normal copper electric wire. When this terminal crimping operation is completed, the crimping jig is raised to complete the terminal crimping operation (see FIG. 3D).

  The reason why the compression ratio of the conduction barrel region 22 of the terminal 1 to the aluminum electric wire 40 is limited in this way is based on the support by many experimental data. explain.

  The terminal-attached aluminum electric wire according to the present embodiment in a state where the terminal is thus crimped to the aluminum electric wire is shown as a side view in FIG. 4 (a) and 4 (b) show the crimped sections of the sections IVA-IVA and IVB-IVB in FIG.

  A conductor having a large cross-sectional area, such as cross-sectional example A shown in FIG. 4A, is crimped in a low compression state. On the other hand, a conductor having a small cross-sectional area as in the cross-sectional example B shown in FIG. 4B is pressure-bonded in a highly compressed state.

  That is, when the compression rate of the cross-sectional example B having a small conductor cross-sectional area is 70%, this corresponds to a terminal crimping structure to an aluminum wire in the conduction barrel region 22 of the wire barrel 20. On the other hand, compared with the cross-sectional example B, the cross-sectional example A having a large conductor cross-sectional area has a compression rate lower than 70% (numerically large) and corresponds to a terminal crimping structure in the holding barrel region of the wire barrel 20.

  Hereinafter, the reason why the compression rate is set will be described. The conventional terminal crimping structure to a copper wire is managed so as to have a relatively high compression rate. Specifically, although the compression rate is slightly different depending on the type of terminal and the diameter of the wire, the compression rate is approximately 75- It is managed within the range of 95%.

  On the other hand, when the compression ratio of the conductive barrel region of the aluminum electric wire is crimped at the current control value, an increase in resistance occurs in an environmental test that requires high and low temperatures, and stable electrical connection cannot be maintained.

  However, the inventor has succeeded in achieving a stable electrical connection by specifying an optimum control value in the range of 50 to 70% only in the conduction barrel region of the aluminum wire, clearing the environmental test, and conducting a stable electrical connection through a huge experiment. . This point will be described in the following example section.

  The reason why the terminal compression rate (area reduction rate) is inappropriate when it is 71% or more and when it is less than 50% is as follows.

  The reason why it is inappropriate when the terminal compression ratio is 71% or more is, as will be apparent from the column of Examples described later, the resistance of the crimped part before and after the environmental test (cooling cycle) increases to 1.0 mΩ or more, This is because a stable electrical connection state cannot be maintained. In addition, when the terminal compression ratio is less than 50%, the reason why it is inappropriate is that if the conductor cross-sectional area after terminal crimping is highly compressed to 1/2 or less of the conductor cross-sectional area before terminal crimping, the crimping strength is significantly reduced. It is.

  In addition, since the holding barrel region of the wire barrel is crimped at a compression rate lower (numerically larger) than the conductive barrel region described above, the crimping strength can be sufficiently secured at this portion, and the terminal Can be securely connected to the aluminum wire.

  Then, the experimental result used as the support limited to the terminal compression rate mentioned above is demonstrated in the column of an Example.

  Thermal shock test (cold shock test), that is, low temperature environment (−40 ° C.) for aluminum wires with terminals in which the conductive barrel region 22 is crimped to the aluminum wire conductors at various compression rates in a closed barrel type crimp terminal. The test was repeated alternately and continuously in a high temperature environment (120 ° C.), the appearance of the terminal crimping part before and after the test was compared, and the resistance change before and after the test of the electrical connection part was measured.

  This thermal shock test is particularly suitable for evaluating the connection performance of the terminal crimping part. The thermal shock test was performed for 1000 cycles.

  Table 1 shows a representative example of a list of resistance increase values before and after the environmental test (cooling shock test) obtained as described above. A graph of this is shown in FIG.

この表１の結果から、発明者は抵抗上昇１．０ｍΩ以内を安定目標値として７０％を端子圧縮率の上限における境界に設定した。

From the results shown in Table 1, the inventors set 70% as the boundary at the upper limit of the terminal compression rate, with a resistance increase within 1.0 mΩ as a stable target value.

  The graph shown in FIG. 5 is a representative example and differs slightly depending on various aluminum wires and wire diameters. However, it has been found that the conduction barrel region 22 is a stable region in the range of 50% to 70% compression. In addition, the lower limit value is that the resistance increase value is similarly reduced as the compression ratio is lowered. However, when the terminal compression ratio of the conduction barrel region 22 is less than 50%, that is, in the conduction barrel region 22 before terminal crimping. If the conductor cross-sectional area after terminal crimping is highly compressed to 1/2 or less with respect to the conductor cross-sectional area, the crimping strength is significantly reduced and the mechanical connection strength is impaired, so the lower limit of the compressibility is 50%. did.

  According to the above evaluation test, by crimping the terminal conductive barrel region 22 to the aluminum wire in a compression rate range of 50% to 70%, and crimping the aluminum wire to the terminal holding barrel region 21 at the conventional compression rate, It was found that a stable conductive connection can be maintained between the aluminum wire and the terminal without impairing the strength of the terminal crimping portion.

  In order to prevent oxidation due to air and corrosion due to moisture, higher reliability can be obtained by applying a rust preventive grease or the like to the connecting portion between the terminal and the aluminum wire conductor.

  Moreover, instead of the upper half of the wire barrel being crimped in a substantially W shape, a cross-section VI-VI in FIG. 6A is a so-called C-shape as shown in the cross-sectional view in FIG. When performing crimping, the conductive barrel region 52 of the wire barrel 50 may be crimped at the compression rate of 50 to 70% described above.

  In addition, in the case of so-called four-point crimping for compressing the four corners of the wire barrel as shown in the sectional view of FIG. 6C in the section VI-VI of FIG. 6A, the conduction barrel region of the wire barrel is described above. You may crimp by the compression rate of 50 to 70%.

  6A, when the so-called hexagonal compression is performed in which the wire barrel 70 is compressed into a hexagonal shape when viewed from the end, as shown in the sectional view of FIG. 6D. The conductive barrel region 72 may be pressure-bonded at the compression rate of 50 to 70% described above.

  Further, as shown in FIG. 7A, in addition to hexagonal crimping, the compression ratio may be controlled more positively by further crimping the conducting barrel region 72 of the wire barrel with a special crimping jig. .

  Similarly, as shown in FIG. 7B, in addition to the so-called C-type crimping, the compression ratio is more positively controlled by further crimping the conduction barrel region 62 of the wire barrel with a special crimping jig. May be.

  Further, in the above-described embodiment, the case where a closed barrel type crimp terminal is crimped to an aluminum electric wire has been described. However, the present invention is not necessarily limited thereto, and the present invention can also be applied to a crimp sleeve connecting aluminum wires. . That is, the scope to which the present invention is applied is not limited to the closed panel type crimp terminal in terms of words, and includes a crimp sleeve. Specifically, each aluminum wire crimping portion of the crimping sleeve is divided into a conducting sleeve region (corresponding to the above-described conducting barrel region) and a holding sleeve region (corresponding to the above-described retaining barrel region), and the holding sleeve region is conventionally provided. It is preferable that the conductive sleeve region is crimped at a compression rate of 50% to 70% defined in the present invention. Thereby, an effect equivalent to crimping a closed barrel type terminal to the aluminum electric wire can be exhibited.

  Although the present invention can be applied to a crimping terminal for a connector that can be inserted / removed for connecting an aluminum electric wire that uses aluminum as a conductor, this application is limited to the wiring harness wiring in an automobile as a main application. In addition, the present invention can be used in various fields in which a terminal is crimped to the end portion of such an aluminum electric wire.

It is the perspective view which showed the terminal crimping structure to the aluminum electric wire concerning one Embodiment of this invention. It is a side view in the terminal crimping structure of the aluminum electric wire shown in FIG. It is process drawing which shows the terminal crimping method to the aluminum electric wire concerning one Embodiment of this invention in order of Fig.3 (a) thru | or FIG.3 (d). FIG. 4 is a cross-sectional view taken along the line IVA-IVA in FIG. 2 (FIG. 4A) and a cross-sectional view taken along the line IVB-IVB (FIG. 4B). It is the figure which showed the test data of the Example of this invention. Sectional drawing which showed the various modifications regarding the terminal crimping structure of one Embodiment of this invention in the perspective view (FIG. 6 (a)) and cross section VI-VI of FIG. 6 (a) which shows the aluminum wire by which the terminal was crimped | bonded (FIG. 6B to FIG. 6D). It is sectional drawing ((FIG. 7 (a) and FIG.7 (b)) which showed the further modification in addition to FIG.6 (b)-FIG.6 (d).

Explanation of symbols

1 terminal 10 terminal connection portion 20 wire barrel 21 holding barrel region 22 conduction barrel region 40 aluminum wire 41 conductor portion 50, 60, 70 wire barrel 52, 62, 72 conduction barrel region 80 base 90 crimping jig 91, 92 terminal crimping Part

Claims (3)

It is a terminal crimping structure to an aluminum electric wire that crimps a terminal to an aluminum electric wire consisting of a large number of stranded wires and a covering portion covering the stranded wire,
The terminal is a closed barrel type terminal and has a wire barrel that is crimped to the conductor portion of the aluminum electric wire,
The compression ratio of the aluminum electric wire conductor portion in the region where the electrical connection between the wire barrel and the aluminum electric wire is ensured is 50 to 70% in the ratio of the aluminum electric wire conductor portion cross-sectional area of the crimped portion / the pre-crimped aluminum electric wire conductor portion. Terminal crimping structure to aluminum wire, characterized by being in range. It is a terminal crimping method to an aluminum electric wire that crimps a terminal to an aluminum electric wire consisting of a large number of stranded wires and a covering portion covering the stranded wire,
While preparing an aluminum wire,
Prepare a terminal that is a closed barrel type terminal and has a wire barrel that is crimped to the conductor portion of the aluminum electric wire,
The compression ratio of the aluminum electric wire conductor portion in the region where the electrical connection between the wire barrel and the aluminum electric wire is ensured is 50 to 70% in the ratio of the aluminum electric wire conductor portion cross-sectional area of the crimped portion / the pre-crimped aluminum electric wire conductor portion. A method for crimping a terminal to an aluminum wire, wherein the terminal is crimped to the aluminum wire so as to be within a range. A method for producing a terminal-attached aluminum electric wire by crimping a terminal to an aluminum electric wire consisting of a large number of stranded wires and a covering portion covering the stranded wire,
While preparing an aluminum wire,
Prepare a terminal that is a closed barrel type terminal and has a wire barrel that is crimped to the conductor portion of the aluminum electric wire,
The compression ratio of the aluminum electric wire conductor portion in the region where the electrical connection between the wire barrel and the aluminum electric wire is ensured is 50 to 70% in the ratio of the aluminum electric wire conductor portion cross-sectional area of the crimped portion / the pre-crimped aluminum electric wire conductor portion. A terminal-attached aluminum electric wire is manufactured by crimping the terminal to the aluminum electric wire so as to be within a range.

Images