JP2017016864A - Wire with terminal, wiring harness structure, and manufacturing method of wire with terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wire with terminal or the like capable of securing a high cut-off performance.SOLUTION: In a lead wire 25 that is formed by twisting a plurality of strands together, ruggedness is formed in an outer circumferential part. A circumscribed circle 29 of the lead wire 25 is estimated in such a manner that all the strands are included. With the circumscribed circle 29 defined as a reference, a distal end of a coating part 27 protruding from the circumscribed circle 29 in a center direction is defined as a trough 30. A distance between the circumscribed circle 29 and the trough 30 in a portion with maximum depth of the trough 30 is defined as trough depth, On a center line of the circumscribed circle 29 indicating the trough depth, a distance between the circumscribed circle and an outer peripheral surface of the coating part 27 is defined as coating part thickness. The trough depth/coating part thickness is 55% or less preferably or is 45% or less further preferably.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electric wire with a terminal used for an automobile or the like.

  Conventionally, the connection between an electric wire and a terminal in an automotive wire harness is generally a crimp bonding in which the electric wire is crimped by a terminal called an open barrel type. However, in such a wire harness, when moisture or the like adheres to the connection portion between the electric wire and the terminal, the oxidation of the metal surface used for the electric wire proceeds, and the resistance at the joint increases. Moreover, when the metal used for an electric wire and a terminal differs, the corrosion between different metals will advance. The progress of the corrosion of the metal material in the connection portion causes cracks in the connection portion and contact failure, and thus cannot be affected by the product life. Particularly in recent years, wire harnesses in which the electric wires are made of an aluminum alloy and the terminals are made of a copper alloy are being put into practical use, and the problem of corrosion at the joints has become prominent.

  Here, when moisture adheres to a contact portion between different metals such as aluminum and copper, so-called galvanic corrosion may occur due to a difference in corrosion potential. In particular, since the potential difference between aluminum and copper is large, corrosion on the aluminum side, which is electrically base, proceeds. For this reason, the connection state between the conducting wire and the crimp terminal becomes unstable, and there is a possibility that the electrical resistance increases due to an increase in contact resistance or a decrease in the wire diameter, and further, disconnection occurs, leading to malfunction of the electrical component or a malfunction.

  In such a terminal-attached electric wire that comes in contact with a dissimilar metal, for example, a terminal having a cylindrical crimping part sealed at one end is used, and after inserting the end of the electric wire into the cylindrical crimping part, the cylindrical crimping is performed. There has been proposed a method of crimping a portion by caulking (Patent Document 1).

JP 2014-164913 A

  As in Patent Document 1, when the coated conductor is inserted into and crimped to the terminal with the end of the crimping part sealed, the coating part and the coating crimping part are in close contact with each other, so that water enters the inside of the terminal. Can be prevented.

  However, although the inner conductor is also compressed in the coated crimping portion, if there is a large uneven shape on the outer periphery of the inner conductor, the thickness of the coated portion varies after crimping. For this reason, in order to ensure higher water-stopping properties, it is desirable to make the change in the thickness of the covering portion as small as possible.

  This invention is made | formed in view of such a problem, and it aims at providing the electric wire with a terminal etc. which can ensure high water-stopping.

  In order to achieve the above-described object, a first invention is a terminal-attached electric wire in which a coated conductor and a terminal are connected, and the terminal includes a crimping portion to which the coated conductor is crimped, and a terminal body. The crimping part has a closed cylindrical shape, and has a covering crimping part for crimping the covering part, and a conductor crimping part for crimping the conductive wire exposed from the covering part. When a circumscribed circle of the conducting wire is assumed in a cross section formed by twisting strands and perpendicular to the longitudinal direction of the coated conducting wire, the circumscribed circle and the covering portion protruding from the circumscribed circle in the center direction When the distance of the portion having the largest distance from the tip is the trough depth, and the distance from the circumscribed circle to the outer peripheral surface of the covering portion at the trough depth portion is the covering portion thickness, the trough depth / The covering part thickness is 55% or less A terminal with a wire.

  It is desirable that the valley depth / the coating thickness is 45% or less.

  The conductor may be preliminarily compressed and deformed into a substantially circular shape before being covered with the covering portion.

  It is desirable that an outer diameter of the circumscribed circle is 1.7 mm to 2.1 mm.

  According to the first invention, in the cross section perpendicular to the longitudinal direction of the coated conducting wire, a circumscribed circle of the conducting wire is assumed, and the valley at the distance from the circumscribed circle to the front end of the coated portion with respect to the coated portion thickness By making the ratio of the depth of the portion 55% or less, the change in the thickness of the covering portion can be reduced even after the covering portion is crimped. For this reason, the dispersion | variation in the compression amount by the site | part of a coating | coated part can be made small. As a result, the adhesive force between the covering portion and the covering pressure-bonding portion becomes substantially uniform over the entire circumference, and the water stoppage can be increased.

  Such an effect on water-stopping is particularly great when the aforementioned ratio is 45% or less.

  Moreover, the ratio mentioned above can be made small by compressing and deform | transforming conducting wire beforehand to a substantially circular shape before coat | covering with a coating | coated part.

  Moreover, in this invention, it is especially effective with respect to the comparatively thick covered conducting wire whose outer diameter of a circumscribed circle is 1.7 mm-2.1 mm.

  A second invention is a wire harness structure in which a plurality of terminal-attached electric wires according to the first invention are bundled.

  In the present invention, a plurality of electric wires with terminals can be bundled and used.

  3rd invention is a manufacturing method of the electric wire with a terminal by which the covering conducting wire and the terminal were connected, Comprising: The said terminal has a crimping | compression-bonding part to which the said covering conducting wire is crimped, and a terminal main body, The said crimping | compression-bonding part Has a closed crimping part that crimps the covering part, and a conductor crimping part that crimps the conductive wire exposed from the covering part, and the conducting wire twists a plurality of strands. In addition, by compressing into a substantially circular shape and then covering with the covering portion, in the cross section perpendicular to the longitudinal direction of the coated conducting wire, when the circumscribed circle of the conducting wire is assumed, the circumscribed circle and the circumscribed circle The distance of the portion where the distance from the tip of the covering portion protruding in the center direction is the largest is the trough depth, and the distance between the circumscribed circle and the outer peripheral surface of the covering portion at the portion of the trough depth is the covering portion. Assuming thickness, the valley depth / the coating thickness is 55% or less. And, as the compression ratio of the insulation crimp portion is 45% to 90%, it is a manufacturing method of an electric wire with terminal, characterized by crimping the insulated conductive wires in the insulation crimp portion.

  According to 3rd invention, the electric wire with a terminal which is excellent in the water stop in a covering crimping part can be manufactured.

  ADVANTAGE OF THE INVENTION According to this invention, the electric wire with a terminal etc. which can ensure high water stop can be provided.

The perspective view of the electric wire 10 with a terminal. Sectional drawing of the electric wire 10 with a terminal. (A), (b) is sectional drawing of the covering conducting wire 23. FIG. The disassembled perspective view of the electric wire 10 with a terminal. It is sectional drawing which shows the state which has arrange | positioned the crimping | compression-bonding part 5 between metal mold | die 31a, 31b, (a) is a figure which shows before crimping, (b) is a figure which shows the crimped state. Schematic which shows a test apparatus.

  FIG. 1 is a perspective view showing an electric wire 10 with a terminal according to the present invention, and FIG. 2 is an axial sectional view of the electric wire 10 with a terminal. The electric wire with terminal 10 is configured by crimping the terminal 1 and the coated conductor 23.

  The covered conductive wire 23 is configured by covering the conductive wire 25 with an insulating covering portion 27. The conducting wire 25 is made of, for example, an aluminum-based material. When the covered conductor 23 is inserted into the crimping part 5 of the terminal 1, a part of the covering 27 at the tip of the covered conductor 23 is peeled off to expose the conductor 25. In addition, as the coating | coated part 27, what is normally used in the field | area of this technique, such as polyvinyl chloride (PVC) and polyethylene, can be selected.

  The terminal 1 is made of copper and includes a terminal body 3 and a crimping portion 5. The terminal body 3 is formed by forming a plate-shaped material having a predetermined shape into a cylindrical body having a rectangular cross section. The terminal body 3 has an elastic contact piece 15 formed at the front end portion 17 by folding a plate-like material into a rectangular cylinder. The terminal body 3 is connected by inserting a male terminal or the like from the front end portion 17.

  The crimping part 5 is formed by rounding a plate-like material so that it has a circular cross section, butting the side edges of the plate-like material together and joining them together at the joining part 21. Further, a sealing portion 11 is provided at the front end portion (terminal body 3 side) of the crimping portion 5. That is, the crimping part 5 is substantially cylindrical with one side closed, and is sealed except for the rear end part 19 into which the covered conductor is inserted. In addition, the junction part 21 and the sealing part 11 are welded by laser welding etc., for example. From the rear end portion 19 of the crimp portion 5 formed in a cylindrical shape, the covered conductor 23 is inserted and crimped.

  The crimping section 5 includes a coated crimping section 9 that crimps the coated section 27 of the coated conducting wire 23, and a conductor crimping section 7 that crimps a portion where the coating section 27 is removed and the conducting wire 25 is exposed at the tip of the coated conducting wire 23. Consists of.

  FIG. 3A is a cross-sectional view taken along the line AA in FIG. 2 and is a cross-sectional view perpendicular to the longitudinal direction of the coated conductor 23. The conducting wire 25 is formed by twisting a plurality of strands. In the illustrated example, the seven strands are arranged almost closely. The number and arrangement of the strands are not limited to the illustrated example.

  As described above, the conductive wire 25 formed by twisting a plurality of strands has an uneven shape on the outer peripheral portion. Here, a circumscribed circle 29 of the conducting wire 25 is assumed so as to include all the strands (indicated by a dotted line in the figure). With this circumscribed circle 29 as a reference, the tip of the covering portion 27 that protrudes from the circumscribed circle 29 toward the center is defined as a trough 30 (indicated by a black circle in the figure). In addition, when each strand is contacting, the trough part 30 substantially corresponds with the contact part of strands. On the other hand, even when the strands are slightly separated from each other, the tip of the covering portion 27 (a point closest to the center of the circumscribed circle 29 with respect to the periphery) is defined as a trough.

  Here, in the example shown in the figure, since the valleys 30 are formed between the strands, six valleys are formed. Therefore, the distance between the circumscribed circle 29 and the valley portion 30 is obtained on the center line of the circumscribed circle 29 passing through each valley portion 30. In the present invention, the depth (B in the figure) between the circumscribed circle 29 and the valley portion 30 of the portion where the depth of the valley portion 30 is deepest (the portion farthest from the circumscribed circle 29) is the valley depth. .

  Further, on the center line of the circumscribed circle 29 indicating the valley depth, the distance (C in the figure) between the circumscribed circle and the outer peripheral surface of the covering portion 27 is defined as the covering portion thickness. When the center of the circumscribed circle 29 coincides with the center of the covering portion 27, the thickness of the covering portion 27 is substantially constant at any part.

  Here, in the present invention, the valley depth / cover thickness (= B / C) is desirably 55% or less, and more desirably 45% or less. That is, it is desirable that the trough depth is smaller than the covering portion thickness. In the part where the valley depth is large, when the covering part 27 is pressure-bonded, the compressibility of the covering part 27 becomes smaller than the other part. For this reason, when the trough depth is increased, the adhesion between the covering portion 27 and the covering pressure-bonding portion 9 is weakened, and the water stoppage may be deteriorated. In particular, when the covering portion thickness is reduced, the influence of the valley depth is increased. Therefore, it can suppress that water stoppage worsens by making trough part depth / coating | coated part thickness into said range.

  As a method for reducing the valley depth in this way, for example, the outer diameter of the conducting wire 25 can be made closer to a circle by increasing the number of strands using thinner strands. In the present invention, the outer diameter of the strand is preferably 0.1 to 0.5 mm. If it is thinner than this, the handleability is poor and there is a risk of disconnection. On the other hand, if it is thicker than this, the valley depth is increased, which is not desirable.

  In addition, the conductive wire 25 may be compressed in advance before being covered with the covering portion 27 so as to approximate a substantially circular shape. FIG. 3B shows a state in which each strand is twisted and compressed into a substantially circular shape and then covered with a covering portion 27. Even in this case, similarly to the example shown in FIG. 3A, the valley depth (B) and the covering portion thickness (C) can be specified. By compressing the conducting wire 25, the strand is deformed and the trough 30 is crushed. Therefore, if a compressing conducting wire is used, the trough depth (B) can be reduced.

  Here, the present invention is particularly effective for 2.0 sq (a coated conductor having an outer diameter of the conductor 25 of 1.7 mm) to 2.5 sq (a coated conductor having an outer diameter of the conductor 25 of 2.1 mm). is there. A coated conductor having a diameter larger than this is such that the thickness of the covering portion 27 is increased, so that the above-described ratio of the valley depth / covering portion thickness tends to be small. On the other hand, with a coated conductor thinner than this (for example, 0.5 sq to 0.75 sq), the thickness of the coated portion 27 is originally thin, and a compression conductor may be used from the viewpoint of preventing misalignment. There may be a case where sufficient water stoppage can be secured even for the attached electric wire.

  On the other hand, in the case of an electric wire of 2.0 sq to 2.5 sq, since the coating thickness is relatively thick compared to a coated conductor thinner than this, the influence of the above-mentioned misalignment is difficult to occur, and conventionally a compressed electric wire is also used. There wasn't. That is, the conventional compression conducting wire is performed to prevent the core from being misaligned with respect to the thin-diameter coated electric wire, and is not performed to ensure water-stopping as in the present invention. There wasn't.

  As described above, in the case of 2.0 sq to 2.5 sq in which the problem of misalignment does not occur, conventionally, the compression process for obtaining the compression conductor was not performed. For this reason, trough depth / cover thickness increases. On the other hand, in the present invention, with respect to the above-described size of the covered electric wire applied to the one-end sealed terminal, the water depth is improved by setting the valley depth / cover thickness to a predetermined value or less. This is what we found.

  Next, the process for manufacturing the electric wire with terminal will be described. FIG. 4 is an exploded perspective view showing a state before the covered conductor 23 is inserted into the terminal 1. First, as shown in FIG. 4, the covering portion 27 having a predetermined length at the tip of the covered conducting wire 23 is removed to expose the conducting wire 25. Next, the covered conductor 23 is inserted into the cylindrical crimping part 5. At this time, the exposed portion of the conductive wire 25 is located inside the conductor crimping portion 7, and the covering portion 27 is located inside the covering crimping portion 9.

  Note that, as described above, the crimping part 5 is rolled into a substantially cylindrical shape, and the edges are joined by the joining part 21. Further, a sealing portion 11 is provided at the front end portion (terminal body 3 side) of the crimping portion 5. That is, the crimping part 5 is sealed except for the rear end part 19 into which the covered conducting wire 23 is inserted.

  FIG. 5A is a cross-sectional view showing the molds 31a, 31b and the like before pressure bonding, and FIG. 5B is a cross-sectional view showing the pressure-bonding portion 5 during pressure bonding. The mold 31 a has a semi-cylindrical cavity extending in the longitudinal direction, corresponds to the coated crimping portion 9, and has a large diameter portion 34 having a radius slightly smaller than the radius of the coated crimping portion 9, and the conductor crimping portion 7. And a small-diameter portion 32 having a radius smaller than that of the large-diameter portion 34. The mold 31b has a semi-cylindrical cavity extending in the longitudinal direction, and the radii of the portions corresponding to the conductor crimping part 7 and the covering crimping part 9 are different from those of the mold 31a. The large diameter portion 34 is a portion for crimping the coated crimp portion 9, and the small diameter portion 32 is a portion for crimping the conductor crimp portion 7.

  As shown in FIG. 5B, when the molds 31 a and 31 b are engaged and the crimping part 5 is compressed, the crimping part 5 is crimped to the conductor 25 and the covering part 27. The electric wire 10 with a terminal is manufactured by the above. In addition, it is not necessary to form uneven | corrugated shape etc. in the inner surface of metal mold | die 31a, 31b. As described above, according to the present invention, since the thickness of the covering portion 27 is made uniform in the circumferential direction to improve the water stop, the inner surface of the covering pressure-bonding portion 9 may be smooth.

  Here, if the total cross-sectional area of the coated conductor wire 23 in the coating part 27 before crimping is A0, and the total cross-sectional area inside the coated crimping part 9 after crimping is A1, A1 / A0 is the compression ratio. In the present invention, the compression ratio is desirably 45 to 90%, and more desirably 50 to 80%.

  As described above, by setting the valley depth / covering portion thickness to a predetermined value or less as in the present embodiment, the covering portion 27 is compressed substantially uniformly over the entire circumference in the covering crimping portion 9. It is possible to ensure a water-stopping property.

  Next, an electric wire with a terminal according to the present invention and an electric wire with a terminal as a comparison were made as prototypes and a performance test was performed on each sample, which will be described below.

  Experiments were conducted to determine whether air was leaked from the rear end portion of the wire with terminal from the coated conductor of the wire. FIG. 6 shows an outline of the experimental method. In the experiment, the terminal 1 crimped to the terminal-attached electric wire 10 was placed in a water tank 41 containing water, and pressurized air was sent from the end of the terminal-attached electric wire 10 toward the terminal 1 by the regulator 42.

(Wire with terminal)
The diameter of the conducting wire is 2.1 mm, the outer diameter of the electric wire is 2.8 mm, and the length of the electric wire is 30 cm. And the edge part of the electric wire which exposed the core wire was inserted in the crimping | compression-bonding part of this crimping terminal, and the crimping | compression-bonding part was crimped | bonded using the crimping | compression-bonding apparatus provided with the crimping type shown in FIG. In this case, the compression ratio of the electric wire in the coated crimping portion (the ratio of the cross-sectional area after compression to the cross-sectional area before compression) was set to 70%.

  Examples 1 and 2 and Comparative Example 1 have different valley depth / cover thickness. The trough depth and the coating thickness were measured using a VR3000 manufactured by Keyence Corporation by cutting the coated conductor and polishing the cut surface.

For each electric wire with a terminal, a sample left for 120 hours in an 80 ° C. environment and a sample left for 400 hours in an 80 ° C. environment were prepared, and the presence or absence of air leaks was confirmed. The air pressure was 30 kPa, and n = 10 was evaluated for each. At this time, no air leak was confirmed.
In addition, in order to confirm the water-stopping characteristics in a harsher environment, each terminal-attached wire is left at 120 ° C. for 120 hours, after 240 hours, after 400 hours, after 500 hours, and after 600 hours. In each of the following, the presence or absence of air leaks was confirmed. The air pressure was 30 kPa, and n = 10 was evaluated for each. The results are shown in Table 1.

  In Table 1, “◯” indicates that no air leak occurred, “Δ” indicates that air leak was partially confirmed, and “×” indicates that all air leaks were confirmed. As shown in Table 1, in Example 1 where the valley depth / cover thickness is 45%, no occurrence of air leak was observed in all the times. In Example 2 where the trough depth / cover thickness was 55%, air leaks were partially observed after being left for 500 hours, but generally good results could be obtained.

  On the other hand, in Comparative Example 1, since the valley depth / cover thickness exceeds 55%, some air leaks are already observed after leaving for 120 hours, and all air leaks after leaving for 600 hours. confirmed.

  In addition, this result showed the same tendency, even if it changed the compression rate in the range of 50 to 80%. The same result was obtained even when the diameter of the conducting wire was 1.7 mm.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

  For example, although the Example described the case where aluminum was used for the electric wire, it is not limited to this, You may use copper for an electric wire.

  Further, a plurality of electric wires with terminals according to the present invention can be bundled and used. In the present invention, a structure in which a plurality of electric wires with terminals is bundled in this way is referred to as a wire harness structure.

1 ......... Terminal 3 ......... Terminal body 5 ......... Crimping part 7 ......... Coating crimping part 9 ......... Conductor crimping part 10 ......... Wire with terminal 11 ......... Sealing part 15 ......... Elasticity Contact piece 17 ......... Front end 19 ......... Rear end 21 ......... Joint portion 23 ......... Coated conductor 25 ......... Conductor 27 ......... Coating 29 ......... circumscribed circle 30 ......... Tani 31a, 31b ............ Die 32 ......... Small diameter part 34 ......... Large diameter part 41 ......... Water tank 43 ......... Regulator

Claims (6)

It is an electric wire with a terminal in which a coated conductor and a terminal are connected,
The terminal has a crimping portion to which the coated conductor is crimped, and a terminal body,
The crimping part has a closed cylindrical shape, and has a covering crimping part that crimps the covering part, and a conductor crimping part that crimps the conductive wire exposed from the covering part,
The conducting wire is formed by twisting a plurality of strands,
In a cross section perpendicular to the longitudinal direction of the covered conductor, when a circumscribed circle of the conductor is assumed, the distance between the circumscribed circle and the tip of the covering portion protruding from the circumscribed circle in the central direction is the largest. When the distance is a trough depth and the distance from the circumscribed circle at the portion of the trough depth to the outer peripheral surface of the covering portion is a covering portion thickness, the trough depth / the covering portion thickness is 55%. The electric wire with a terminal characterized by the following.   The terminal-attached electric wire according to claim 1, wherein the trough depth / the covering thickness is 45% or less.   The electric wire with a terminal according to claim 1 or 2, wherein the conductive wire is preliminarily compressed and deformed into a substantially circular shape before being covered with the covering portion.   The electric wire with a terminal according to any one of claims 1 to 3, wherein an outer diameter of the circumscribed circle is 1.7 mm to 2.1 mm.   A wire harness structure comprising a plurality of electric wires with terminals according to any one of claims 1 to 4. A method of manufacturing a terminal-attached electric wire in which a coated conductor and a terminal are connected,
The terminal has a crimping portion to which the coated conductor is crimped, and a terminal body,
The crimping part has a closed cylindrical shape, and has a covering crimping part that crimps the covering part, and a conductor crimping part that crimps the conductive wire exposed from the covering part,
When the conductor is assumed to be a circumscribed circle of the conductor in a cross-section perpendicular to the longitudinal direction of the coated conductor by twisting a plurality of strands and compressing it into a substantially circular shape and then covering with the covering portion The distance between the circumscribed circle and the tip of the covering portion that protrudes in the center direction from the circumscribed circle is defined as the trough depth, and the circumscribed circle and the covering at the trough depth portion. When the distance to the outer peripheral surface of the part is the covering part thickness, the valley depth / the covering part thickness is 55% or less,
The method for producing a terminal-attached electric wire, wherein the coated conductor is crimped by the coated crimping portion so that a compression rate of the coated crimped portion is 45% to 90%.

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