JP2016201313A - Wire harness and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a wire harness, capable of achieving high bond strength without increasing the number of components, and a wire harness having high bond strength.SOLUTION: A wire harness is manufactured by: producing a plurality of electric wires 2 having a conductor wire 21 comprising copper or copper alloy, and an insulation coating 22 coating the outer periphery of the conductor wire 21; removing the insulation coating 22 of a part corresponding to a branch part 11 from the electric wire 2 followed by forming an electric conductor exposed part 211; roughening the conductor exposed part 211 of at least one electric wire 2 in the individual branch part 11 so as to bring an arithmetic average roughness Ra obtained by measuring in a direction in parallel to the longitudinal direction to 0.3 μm or more; and bonding the electric conductor exposed part 211 of the opposite electric wire 2 to the roughened electric conductor exposed part 211 by ultrasonic welding followed by forming the branch part 11.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a wire harness and a manufacturing method thereof.

  The wire harness has a branch portion in which a plurality of electric wires are connected to each other. The wires are connected to each other at the branching portion by removing the insulation coating and exposing the inner conductor, and then joining the conductors by a method such as welding or pressure bonding. In order to suppress separation of the electric wire during wiring or during use, it is preferable that the bonding strength between the conductors at the branch portion is high.

  In recent years, ultrasonic bonding, which is easy for bonding conductors, is frequently used. However, in the automobile field, it is required to make the diameter of the electric wire thinner in order to reduce the weight of the entire automobile, and accordingly, the diameter of the conductor is getting thinner. Therefore, it is difficult to increase the contact area between the conductors in the operation of joining the conductors, and it is difficult to ensure a sufficiently high joining strength.

  Therefore, in order to increase the connection reliability and the bonding strength of the conductor bonding portion, a technique of performing ultrasonic welding or resistance welding from the outside in a state where a plurality of conductors are bundled with a metal sleeve has been proposed (Patent Document 1).

JP 2010-44887 A

  However, in the technique of Patent Document 1, it is necessary to separately use a metal sleeve for joining the conductors, so an increase in the number of parts is inevitable. Therefore, cost reduction is difficult.

  This invention is made | formed in view of this background, and intends to provide the manufacturing method of the wire harness which can implement | achieve high joint strength, without increasing a number of parts, and the wire harness which has high joint strength.

One aspect of the present invention is a method of manufacturing a wire harness having a branch portion in which a plurality of electric wires are connected to each other,
Producing a plurality of electric wires having a conductor wire made of copper or copper alloy and an insulating coating covering the outer periphery of the conductor wire,
Removing the insulating coating of the portion corresponding to the branch from the electric wire to form a conductor exposed portion;
The conductor exposed portion of at least one of the electric wires in each of the branch portions is roughened so that the arithmetic average roughness Ra obtained by measuring in a direction parallel to the longitudinal direction is 0.3 μm or more,
It exists in the manufacturing method of the wire harness characterized by joining the said conductor exposed part of the other party electric wire to the said conductor exposed part roughened by ultrasonic welding, and forming the said branch part.

Another aspect of the present invention is a method of manufacturing a wire harness having a branch portion in which a plurality of electric wires are connected to each other,
A roughened surface comprising a conductor wire made of copper or a copper alloy and having an arithmetic average roughness Ra of 0.3 μm or more obtained by measurement in a direction parallel to the longitudinal direction, and an insulating coating covering the outer periphery of the conductor wire Create multiple wires including wires,
Removing the insulating coating of the portion corresponding to the branch from the electric wire to form a conductor exposed portion;
It exists in the manufacturing method of the wire harness characterized by joining the said conductor exposed part of a partner electric wire to the said conductor exposed part of the said roughened electric wire by ultrasonic welding, and forming the said branch part.

Still another aspect of the present invention is a wire harness in which a plurality of electric wires having a conductor wire made of copper or a copper alloy and an insulating coating covering the outer periphery of the conductor wire are connected to each other,
The electric wire has a conductor exposed portion where the conductor wire is exposed,
The wire harness has a branch portion where the conductor exposed portions are joined to each other by ultrasonic welding,
At least one of the plurality of conductor exposed portions present in the branch portion has a roughened region having an arithmetic average roughness Ra of 0.3 μm or more obtained by measurement in a direction parallel to the longitudinal direction. It is in the wire harness characterized by being.

  In the first aspect of the method of manufacturing the wire harness, the arithmetic average roughness Ra of at least one of the conductor exposed portions in each of the branch portions is set to the specific range by roughening the conductor wire. To do. This makes it easy to increase the real contact area when the exposed conductor exposed portion of the roughened surface is in contact with the exposed conductor portion of the counterpart electric wire, and the bondability of the exposed conductor portion when ultrasonic welding is performed. Can be improved easily. As a result, it is possible to easily improve the joint strength of the branch portion without increasing the number of parts.

  Moreover, the 2nd aspect in the manufacturing method of the said wire harness produces the said roughening electric wire which has the arithmetic mean roughness Ra of the said specific range, and is on the conductor exposed part of this roughening electric wire by ultrasonic welding. Join the exposed conductor of the counterpart wire. In this case as well, the true contact area between the conductor exposed portion of the roughened electric wire and the conductor exposed portion of the counterpart electric wire can be increased as described above. As a result, similar to the first aspect, it is possible to easily improve the joint strength of the branch portion without increasing the number of parts.

  As described above, the wire harness obtained by the above manufacturing method has a high joint strength at the branch portion, and can easily suppress peeling of the electric wire. Moreover, since it is not necessary to separately prepare components such as a metal sleeve during ultrasonic welding, an increase in the number of components can be suppressed.

In Example 1, (a) The top view of the electric wire which formed the conductor exposed part, (b) The top view of the wire harness which formed the branch part. The enlarged view of the branch part of a wire harness in FIG. Explanatory drawing which shows the test method of the tension test in Example 1. FIG. The top view which shows an example of the wire harness which has a branch part in an intermediate part.

  In the method for manufacturing the wire harness, a wire made of pure copper or a copper alloy can be used as the conductor wire of the electric wire. As pure copper, for example, tough pitch copper or oxygen-free copper can be used. Moreover, a conventionally well-known copper alloy can be used as a copper alloy.

  The conductor wire may be composed of a single wire, or may be a stranded wire formed by twisting a plurality of strands. In the case of using a stranded wire, it is also possible to use one subjected to compression molding such as circular compression.

  The said branch part may be formed in the terminal part of the said wire harness, and may be formed in the intermediate part. Further, the number of branch portions may be one, or two or more. The position and the number of the branch portions are appropriately set according to the use of the wire harness. When two or more branch portions are formed, it is sufficient that at least one conductor exposed portion having the arithmetic average roughness Ra in the specific range exists in each branch portion.

  That is, in the first aspect of the manufacturing method, the conductor exposed portion of at least one electric wire in each of the branch portions may be roughened. The roughened conductor exposed portion can increase the real contact area with the conductor exposed portion of the counterpart wire in ultrasonic welding. This effect is obtained when the counterpart conductor exposed portion is roughened and when it is not roughened, that is, when the arithmetic average roughness Ra of the conductor exposed portion is less than 0.3 μm. Can also be obtained.

  From the viewpoint of increasing the real contact area, it is preferable that the number of roughened conductor exposed portions existing in each of the branched portions is larger, and all the exposed conductor portions in the individual branched portions are roughened. Most preferably.

  In addition, the arithmetic average roughness Ra obtained by measuring in the direction parallel to the longitudinal direction in the roughened conductor exposed portion is 0.3 μm or more. Since the conductor exposed portion has the arithmetic average roughness Ra in the specific range, the joint strength at the branch portion can be easily increased. From the viewpoint of further increasing the joint strength at the branch portion, the arithmetic average roughness Ra is more preferably 0.4 μm or more.

  On the other hand, the arithmetic average roughness Ra of the roughened conductor exposed portion is preferably 1.0 μm or less. When the arithmetic average roughness Ra exceeds 1.0 μm, the flexibility of the exposed conductor exposed portion may be deteriorated.

  As a method for roughening the conductor exposed portion, for example, a mechanical method such as sandpaper or blasting, chemical etching, electrolytic etching, or the like can be employed.

  The arithmetic average roughness Ra of the conductor wire can be controlled, for example, by adjusting the conditions for roughening the conductor exposed portion. More specifically, the arithmetic average roughness Ra can be increased by a method such as roughening the sandpaper to polish the exposed conductor.

  In the 2nd aspect of the said manufacturing method, at least 1 should just be the said roughening electric wire among the some electric wires which comprise a wire harness. Similar to the first aspect, the exposed conductor portion of the roughened electric wire can increase the real contact area with the exposed conductor portion of the counterpart wire in ultrasonic welding. This effect can be obtained in any case where the counterpart electric wire is a roughened wire and when it is not a roughened wire, that is, when the arithmetic average roughness Ra of the conductor wire is less than 0.3 μm. .

  The arithmetic average roughness Ra of the conductor wire in the roughened electric wire is 0.3 μm or more, and more preferably 0.4 μm or more. On the other hand, the arithmetic mean roughness Ra of the conductor wire in the roughened electric wire is preferably 1.0 μm or less. The reason for limiting the arithmetic average roughness Ra is the same as in the first aspect.

  In any of the first aspect and the second aspect, the arithmetic average roughness Ra can be measured using a method based on JIS B0601: 2001. Moreover, it can replace with the method based on JISB0601: 2001, and can also measure using a non-contact surface shape measuring machine.

The said manufacturing method can join the said conductor wire which is 0.08-0.22 mm < ² > in cross-sectional area by ultrasonic welding, and can form a branch part. As described above, the method for manufacturing the wire harness can improve the bondability in ultrasonic welding and improve the bondability of the branch portion. Therefore, a thin conductor wire having a cross-sectional area in the specific range can be joined by ultrasonic welding without using a metal sleeve or the like, and a high joining strength can be obtained. Moreover, weight reduction of a wire harness can be more easily performed by using the conductor wire which has the cross-sectional area of the said specific range.

Example 1
The Example of the manufacturing method of the said wire harness is demonstrated concretely. First, an electric wire 2 having a total length of 100 mm having a conductor wire 21 made of copper and an insulating coating 22 covering the outer periphery of the conductor wire 21 was produced. The conductor wire 21 of this example is a circular compression stranded wire in which seven strands are twisted together and then compressed so as to have a circular cross section.

  Next, as shown in FIG. 1A, the insulating coating 22 present at the terminal portion of each electric wire 2 was removed to form a conductor exposed portion 211 having a length of 15 mm. After the conductor exposed portion 211 was polished and roughened by sandpaper, the conductor exposed portion 211 of the counterpart electric wire 2 was joined to the roughened conductor exposed portion 211 by ultrasonic welding to produce the wire harness 1. . Ultrasonic welding was performed under the conditions of a pressure of 1.2 bar, an energy of 100 Ws, and 65% using [Mini IV] manufactured by Schunk.

  As shown in FIG. 1B, the wire harness 1 of the present example includes a branch portion 11 in which the conductor exposed portions 211 are joined to each other by ultrasonic welding. Ultrasonic welding is performed by sandwiching a plurality of exposed conductor portions 211 between a tool and an anvil of an ultrasonic welder and applying pressure while applying ultrasonic vibration. Therefore, depending on the conditions of ultrasonic welding, the surface of the conductor exposed portion 211 may be deformed following the shape of the tool or anvil. In the case of this example, as shown in FIG. 2, the arithmetic average roughness Ra obtained by measuring in the direction parallel to the longitudinal direction is 0.3 μm at the portion of the branching portion 11 that is not in contact with the tool and the anvil. The roughened area A as described above remained.

  In this example, as shown in Table 1, three types of test bodies E1 to E3 were produced in which the cross-sectional area of the conductor wire 21 and the degree of roughening were changed. Further, for comparison with the test bodies E1 to E3, test bodies C1 and C2 that were subjected to ultrasonic welding without roughening the conductor exposed portion 211 were prepared. In Table 1, values obtained by averaging the arithmetic average roughness Ra of each electric wire 2 obtained by measuring in a direction parallel to the longitudinal direction are shown. Moreover, the non-contact surface shape measuring machine (The product made from Zygo, "NewView 7100") was used for the measurement of arithmetic mean roughness Ra. The value of arithmetic average roughness Ra obtained by this is equivalent to the value obtained by the method based on JIS B0601: 2001.

  Subsequently, the tensile test was implemented and the joint strength of the branch part 11 in each test body was measured. In the tensile test, as shown in FIG. 3, two of the three electric wires 2 are fixed, and the remaining one electric wire 2 is pulled at a pulling speed of 50 mm / min while measuring the load applied to the branch portion 11, and the conductor Pulling was continued until the exposed portion 211 peeled off. This tensile test was performed 10 times for each specimen, and the average value of the maximum load from the time when the conductor exposed portion 211 was peeled off from the branch portion 11 was defined as the bonding strength. Table 1 shows the obtained bonding strength.

As is known from Table 1, the test bodies E1 to E3 having the arithmetic average roughness Ra in the specific range have a joint strength equal to or higher than the test bodies C1 and C2 in which the conductor exposed portion 211 is not roughened. showed that. Moreover, the test body E3 in which the cross-sectional area of the conductor wire 21 is 0.13 mm ² showed the same bonding strength as the test body C1 having a larger cross-sectional area.

(Example 2)
In this example, ultrasonic welding of the conductor wire 21 made of a copper alloy is performed. In this example, the same procedure as in Example 1 was performed except that a conductor wire 21 made of a copper alloy having a chemical component of Cu (copper) -1% Fe (iron) -0.5% Ti (titanium) was used. The wire harness 1 was produced. Thereby, the test bodies E11-E17 which have arithmetic mean roughness Ra of the said specific range were obtained. Moreover, for comparison with the test bodies E11 to E17, test bodies C11 to C13 that were subjected to ultrasonic welding without roughening were prepared.

  Table 2 shows the bonding strength of these specimens. The method for measuring the bonding strength is the same as in Example 1.

  As is known from Table 2, the test bodies E11 to E17 having the arithmetic average roughness Ra in the specific range have higher joint strength than the test bodies C11 to C13 in which the conductor exposed portion 211 is not roughened. Indicated. Moreover, it can be understood from the comparison between the test bodies using the conductor wires 21 having the same cross-sectional area that the joint strength tends to increase as the arithmetic average roughness Ra increases when the cross-sectional areas are equal.

  In addition, although the example of the manufacturing method which performs ultrasonic welding after performing the roughening of the conductor exposed part 211 was shown in said Examples 1-2, arithmetic mean roughness Ra of the said specific range was previously shown. Even when ultrasonic welding is performed using the conductor wire 21 provided, the joint strength of the branch portion 11 can be improved. Moreover, although the example of the wire harness 1 which has the branch part 11 in the terminal part was shown in said Example 1-2, as shown in FIG. 4, the branch part 11 is formed in the intermediate part of the wire harness 1b. Even in this case, the bonding strength can be improved by the same manufacturing method as described above. 4 that are the same as those used in FIGS. 1 to 3 indicate the same components as those in the first embodiment.

DESCRIPTION OF SYMBOLS 1 Wire harness 2 Electric wire 21 Conductor wire 211 Electric wire exposed part 22 Insulation coating

Claims (5)

A method of manufacturing a wire harness having a branch portion in which a plurality of electric wires are connected to each other,
Producing a plurality of electric wires having a conductor wire made of copper or copper alloy and an insulating coating covering the outer periphery of the conductor wire,
Removing the insulating coating of the portion corresponding to the branch from the electric wire to form a conductor exposed portion;
The conductor exposed portion of at least one of the electric wires in each of the branch portions is roughened so that the arithmetic average roughness Ra obtained by measuring in a direction parallel to the longitudinal direction is 0.3 μm or more,
A method of manufacturing a wire harness, comprising joining the conductor exposed portion of the counterpart electric wire to the roughened conductor exposed portion by ultrasonic welding to form the branch portion. A method of manufacturing a wire harness having a branch portion in which a plurality of electric wires are connected to each other,
A roughened surface comprising a conductor wire made of copper or a copper alloy and having an arithmetic average roughness Ra of 0.3 μm or more obtained by measurement in a direction parallel to the longitudinal direction, and an insulating coating covering the outer periphery of the conductor wire Create multiple wires including wires,
Removing the insulating coating of the portion corresponding to the branch from the electric wire to form a conductor exposed portion;
A method of manufacturing a wire harness, comprising forming the branch portion by joining the conductor exposed portion of a counterpart electric wire to the conductor exposed portion of the roughened electric wire by ultrasonic welding. The method for manufacturing a wire harness according to claim 1 or 2, wherein the conductor wires having a cross-sectional area of 0.08 to 0.22 mm ² are joined. A wire harness in which a plurality of electric wires having a conductor wire made of copper or a copper alloy and an insulating coating covering the outer periphery of the conductor wire are connected to each other,
The electric wire has a conductor exposed portion where the conductor wire is exposed,
The wire harness has a branch portion where the conductor exposed portions are joined to each other by ultrasonic welding,
At least one of the plurality of conductor exposed portions present in the branch portion has a roughened region having an arithmetic average roughness Ra of 0.3 μm or more obtained by measurement in a direction parallel to the longitudinal direction. A wire harness characterized by The wire harness according to claim 4, wherein the conductor wire has a cross-sectional area of 0.08 to 0.22 mm ² .

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