JP2016046144A - Electric wire with terminal, and wire harness structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric wire with a terminal and the like capable of securing high water cut-off performance.SOLUTION: A terminal 1 comprises the terminal body 3 and a crimp part 5. The crimp part 5 is formed by rounding itself so as to have a cross section of a circular cylinder, butting mutual side edges and joining integrally at a joint part 21. The covered conducting wire 23 is inserted from a rear end part 19 of the crimp part 5 formed in a cylindrical shape. A sealed part 11 is formed in the front end part (terminal body 3 side) of the crimp part 5. The crimp part 5 comprises: a covering crimp part 9 which crimps a cover part 27 of the covered conducting wire 23; and a conductor crimp part 7 which crimps the part where a cover part is removed and a conducting wire 25 is exposed in the tip portion of the covered conducting wire 23. The cover part 27 of the covered conducting wire 23 may use, for example, polyvinyl chloride. Moreover, a resin which constitutes the cover part 27 is blended with an additive. When a strong stress at the time of crimping is applied to the cover part 27, the additive is a component which oozes out on the surface of the cover part 27.SELECTED DRAWING: Figure 1

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 wire harness that comes in contact with a dissimilar metal, for example, a terminal having a cylindrical crimping portion that is closed at one end is used, and after inserting the end of an electric wire into the cylindrical crimping portion, the cylindrical crimping portion is caulked. There has been proposed a method of protecting the end portion of the core wire from adhesion of rainwater, seawater or the like by pressure bonding by processing (Patent Document 1).

JP 2006-319331 A

  However, after sealing the end of the crimping part as in Patent Document 1, if the adhesion after holding at a high temperature is not sufficient, water may enter from the crimping part when applied to an automobile or the like.

  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 cylindrical shape with one closed side, 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, and constitutes the covering part. The terminal-containing electric wire is characterized in that the resin contains at least one additive selected from trimellitic acid, dialkyl phthalate, and diisononyl phthalate.

  The resin is mainly composed of polyvinyl chloride, and the additive exudes to the surface of the resin at the time of pressure bonding, and is a trimellitic acid-based or phthalic acid-based plastic for adjusting the elasticity of the polyvinyl chloride. Desirably, the plasticizer is trimellitic acid-based. You may have the adsorption layer which has the said additive as a main component between the said coating crimping | compression-bonding part and the said coating | coated part of the said terminal. Further, the amount of the additive contained in the coating is preferably 5% to 40% by weight.

  The covering crimping portion has a protruding portion that protrudes from the inner surface of the covering pressing portion and is annularly provided in the circumferential direction, and a concave groove corresponding to the protruding portion is formed on the outer peripheral surface of the protruding portion. May be.

  A plurality of the protrusions may be provided apart from each other in the longitudinal direction of the covering crimping part.

  According to 1st invention, the adsorption | suction effect | action between a coating | coated part and a coating | coated crimping | compression-bonding part can be obtained with the additive added to the coating | coated part. For this reason, a high water stoppage can be ensured by this adsorption action. The adsorbing action by the additive can be obtained by exuding the component of the additive on the surface of the coating part when a strong stress is applied to the coating part or when the coating part is held at a high temperature.

  Thus, a plasticizer can be mentioned as an additive which exudes to the resin surface at the time of pressure bonding or holding at high temperature. As the plasticizer, those based on trimellitic acid or phthalic acid can be used, but trimellitic acid having lower volatility and higher viscosity is particularly desirable.

  In addition, since the ridges projecting on the inner surface of the covering crimping portion are provided annularly in the circumferential direction of the insulating covering portion, water tightness can be reliably ensured in the entire circumferential direction.

  Moreover, watertightness can be further ensured by providing a plurality of ridges in the longitudinal direction.

  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.

  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. 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. It is sectional drawing which shows the state which has arrange | positioned the crimping | compression-bonding part 5 between metal mold | die 35a, 35b, (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. The covered conducting wire 23 is inserted from the rear end portion 19 of the crimping portion 5 formed in a cylindrical shape. 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.

  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. For example, copper or a copper alloy, or a material in which plating is formed on the surface thereof may be used as the covering crimping portion 9. In the plating, it is preferable that the outermost surface in contact with the covering portion 27 is Sn (tin) plating.

  As described above, the covering portion 27 of the covered conductor 23 can be made of, for example, polyvinyl chloride or a non-halogen member. Further, an additive is blended in the resin constituting the covering portion 27. The additive is a component that exudes to the surface of the covering portion 27 when a large stress is applied to the covering portion 27. Desirably, a plasticizer for adjusting the elasticity of the covering portion 27 can be applied as an additive. Specifically, the covering portion 27 is made of polyvinyl chloride, and a plasticizer added to obtain this flexibility can be used.

  As the plasticizer, for example, trimellitic acid type or phthalic acid type can be used. As the trimellitic acid system, for example, trioctyl trimellitic acid can be applied. Examples of phthalic acid-based compounds include dialkyl phthalate and diisononyl phthalate (DiNP). More specifically, as trimellitic acid, for example, Trimex N-08 manufactured by Kao Chemical Co., Ltd. can be used. Moreover, as dialkyl phthalate, for example, V-124 manufactured by Kao Chemical Co., Ltd. can be used. Moreover, as a compounding quantity of these plasticizers, you may be 5% or more and 40% or less in weight ratio%, for example.

  By adding such an additive, the adhesion between the covering portion 27 and the covering pressure-bonding portion 9 can be increased. Such an increase in adhesion due to the addition of the additive is considered to be the following mechanism. When the covering portion 27 is pressure-bonded by the covering pressure-bonding portion 9, the covering portion 27 is strongly compressed. At this time, a part of the additive oozes out in a liquid state on the surface of the covering portion 27. Furthermore, even when kept at a high temperature under such stress, a part of the additive oozes out on the surface of the covering portion 27.

  When the plasticizer oozes out to the surface of the covering portion 27, the adhesion force is increased by the adsorption action between the covering portion 27 and the covering pressure-bonding portion 9. For this reason, a high water-stopping property can be ensured. Here, the adsorption action means not only that the covering portion 27 and the covering pressure-bonding portion 9 are simply pressed and in close contact with each other, but also removing the compressive force (pressing force) between the covering portion 27 and the covering pressure-bonding portion 9. However, it is a phenomenon in which the state of sticking is maintained and it is difficult to separate from each other as if they were adhered. More specifically, an adsorption layer containing a plasticizer as a main component is formed between the covering portion 27 and the covering pressure-bonding portion 9 so that the covering portion 27 and the covering pressure-bonding portion 9 are in close contact with each other. is there. In addition, an adsorption layer shall contain 50% or more of plasticizer components.

  As described above, the additive oozes out at the time of pressure bonding, but when it is kept at a high temperature (particularly at a temperature equal to or higher than the glass transition temperature of the covering portion 27), the additive exudes to the surface of the covering portion 27, thereby increasing the temperature. Adhesion at the time can be ensured. In this case, it is more desirable to use a trimet acid plasticizer having low volatility and relatively high viscosity. That is, when the additive component is a droplet, the wettability is good with respect to the surface of the resin base material (for example, the wettability such that the contact angle of the droplet on the resin surface is 60 degrees or less). A higher viscosity (for example, 200 to 240 mPa · sec) is desirable. By using such an additive, it oozes uniformly over the entire surface of the covering portion 27 and adheres to the inner surface of the covering crimping portion 9 with high adhesion.

  Next, the process of forming an electric wire with a terminal will be described. FIG. 3 is an exploded perspective view showing a state before the covered lead wire 23 is inserted into the terminal 1. First, as shown in FIG. 3, 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. 4A is a cross-sectional view showing the molds 31a, 31b and the like before pressure bonding, and FIG. 4B 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. 4B, 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.

  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 rate is desirably 50 to 80%.

  The electric wire 10 with a terminal of this invention is used for a motor vehicle etc., for example. For this reason, it may be exposed to high temperature, for example in an engine room. Therefore, when used in such applications, it is necessary to maintain water tightness even in high temperature use.

  In order to withstand such high temperature use, for example, it is necessary to maintain watertightness even after 120 ° C. × 120 hours. However, if the resin constituting the covering portion 27 is not appropriate, it is difficult to maintain a sufficient adhesion after holding at a high temperature.

  However, in the present invention, an appropriate additive can be blended in the covering portion 27, and the adhesion between the covering portion 27 and the covering pressure-bonding portion 9 can be maintained at the time of pressure bonding and after holding at a high temperature. For example, even when the compression rate is about 80%, water tightness after holding at a high temperature can be ensured.

  As described above, by adding an appropriate additive to the resin constituting the covering portion 27 as in the present embodiment, it is possible to manufacture the terminal-attached electric wire 10 having excellent water-stopping properties. In particular, after the high temperature is maintained, stress relaxation proceeds due to the shrinkage of the covering portion 27, and there is a concern that the adhesion between the covering portion 27 and the covering crimping portion 9 may be reduced. Occasionally, the additive oozes out so that high adhesion can be maintained.

<Second Embodiment>
Next, a second embodiment will be described. FIG. 5 is a diagram showing a crimping process according to the second embodiment. FIG. 5A is a cross-sectional view showing the molds 35a, 35b and the like before crimping, and FIG. It is sectional drawing which shows the crimping | compression-bonding part 5. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals as those in FIG. 4 and the like, and redundant descriptions are omitted.

  The second embodiment has substantially the same configuration as that of the first embodiment, but is different in that a protruding strip portion 39 is formed on the cover crimping portion 9 by a crimping process.

  The molds 35a and 35b are each formed with a convex portion 37 protruding from the inner surface. The convex portion 37 is continuous in the circumferential direction on the inner peripheral surfaces of the molds 35a and 35b. That is, in a state where the molds 35a and 35b are combined, the convex portion 37 continues in an annular shape in the inner peripheral direction of the molds 35a and 35b. Sites corresponding to the convex portions 37 of the molds 35 a and 35 b are strongly pushed into the outer peripheral surface of the covering crimping portion 9. Therefore, on the inner peripheral surface of the cover crimping portion 9, a protruding ridge portion 39 protruding inward in the radial direction is formed at a portion corresponding to the protruding portion 37 of the molds 35 a and 35 b.

  The ridge 39 is a reduced diameter portion compared to other portions. It should be noted that the number of the ridges 39 is not necessarily two as shown in the figure, but may be at least one. However, it is desirable to form two or more ridges 39 in order to increase the waterstop.

  In this way, by providing the covering crimping portion 9 with the annular projecting ridge portion 39 in the circumferential direction, a portion of the covering portion 27 is crimped by the projecting ridge portion 39 with a stronger force than the other portions, and the high crimping portion. Can be formed. Therefore, it is possible to ensure a higher water stoppage.

  According to the second embodiment, an effect similar to that of the first embodiment can be obtained. Further, the protruding streak portion 39 can ensure higher water stoppage. In addition, by forming the ridge portion 39 in the crimping step, the ridge portion does not get in the way when the covered conductive wire 23 is inserted.

  Next, with respect to the electric wire 10 with a terminal after the heating test shown in FIG. 1, air was sent from the covering portion 27 of the covered conductive wire 23 toward the terminal 1 to evaluate whether air leaks from the rear end portion. FIG. 6 shows an outline of the evaluation method. In the evaluation, the terminal 1 to which the coated conductor 23 was crimped was placed in a water tank 41 containing water, and pressurized air was sent from the end of the coated conductor 23 toward the terminal 1 by the regulator 43. The pressure when leakage was confirmed at the terminal 1 was defined as the leakage pressure.

  Each terminal-attached electric wire 10 subjected to the test changed the resin of the covering portion 27 of the covered conductive wire 23. Specifically, polyvinyl chloride was used as a base material, and the presence or absence of an additive and the type of additive were changed for evaluation. The compression rate was 80% in all cases.

  For comparison, when the leakage before the heating test was evaluated, the leakage pressure was 95 kPa or more in all samples. On the other hand, after the heating test, those using Trimex N-08 manufactured by Kao Chemical Co., Ltd. and those using V-124 manufactured by Kao Chemical Co., Ltd. had a leakage pressure of 95 kPa or more. . That is, sufficient water tightness was ensured. On the other hand, in the case of no additives, leakage was confirmed in part at a pressure of less than 95 kPa.

  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 31a, 31b, 35a, 35b ......... Mold 32 ......... Small diameter part 34 ......... Large diameter part 37 ......... Convex part 39 ......... Convex line part

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 resin constituting the covering portion contains one or more additives selected from trimellitic acid, dialkyl phthalate, and diisononyl phthalate.   The electric wire with a terminal according to claim 1, further comprising an adsorption layer mainly composed of the additive between the coated crimping portion and the coating portion of the terminal.   3. The terminal-attached electric wire according to claim 1, wherein an amount of the additive contained in the covering portion is 5% to 40% by weight. The covering pressure-bonding portion protrudes from the inner surface of the covering pressure-bonding portion, and has a protruding strip portion provided in an annular shape in the circumferential direction,
The electric wire with a terminal according to any one of claims 1 to 3, wherein a concave groove corresponding to the convex portion is formed on an outer peripheral surface of the convex portion.   5. The terminal-attached electric wire according to claim 4, wherein a plurality of the protruding strip portions are provided apart from each other in the longitudinal direction of the covering crimping portion.   A wire harness structure in which a plurality of electric wires with terminals according to any one of claims 1 to 5 are bundled.

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