JP5255404B2 - Connection part and connection method of wire and terminal made of different metals - Google Patents

Description

  The present invention relates to a connection portion and a connection method between an electric wire and a terminal, in which corrosion due to a contact potential difference between the conductor and the terminal is prevented when the conductor of the electric wire and the terminal to be crimped thereto are different metals.

  Usually, a terminal made of copper or a copper alloy (hereinafter referred to as a copper-based material) is used as a connector for connecting a copper conductor. A terminal made of a copper-based material is provided with a contact portion that comes into contact with a mating terminal on the front end side, and a conductor caulking portion and an insulating coating caulking portion that connect an electric wire on the rear end side. To connect a copper conductor wire to such a terminal, remove the insulation coating at the end of the wire to expose the copper conductor, and crimp the conductor crimp to the exposed conductor, and at the same time, the insulation coating crimp to the insulation coating end. Crimp the.

  In the fields of automobiles, office automation equipment, home appliances, etc., copper wires having conductors made of copper-based materials having excellent conductivity have been used as signal lines and power lines. In particular, in the automotive field, high performance and high functionality of vehicles have been rapidly promoted, so that the number of copper electric wires used tends to increase with the increase in various on-vehicle electrical devices and control devices. Is the current situation. Under these circumstances, when trying to improve fuel efficiency by reducing the weight of a vehicle, aluminum wires that are lighter and cheaper than copper wires (the conductor is made of an aluminum-based material) are attracting particular attention in the automotive field. ing.

  However, when an aluminum electric wire is actually used for automobiles, contact with different metals (corrosion) becomes a problem. When wiring an electric wire as well as an aluminum electric wire, it is necessary to attach a connection terminal to the electric wire in order to connect the electric wires or connect the electric wires to the terminals of the electrical equipment. As described above, these terminals and conductors of electric wires are often made of a copper-based material having excellent electrical characteristics. For this reason, when an aluminum electric wire is used, a case where an aluminum-based material and a copper-based material must be contacted / joined somewhere occurs.

  However, when different metals having different standard electrode potentials such as aluminum and copper are brought into contact / joining, electrolytic corrosion occurs at the contact / joining portion. In particular, when the terminal connected to the conductor made of aluminum material is made of copper material, the standard electrode potential difference between the conductor and the terminal is large. When water is exposed to water, ionization of the electrically conductive aluminum conductor proceeds to promote corrosion. As a result, the contact state between the aluminum conductor and the terminal deteriorates and the electrical characteristics become unstable, as well as an increase in contact resistance and an increase in electrical resistance due to a decrease in the conductor cross-sectional area due to corrosion, as well as disconnection. This can lead to malfunctions and malfunctions of electrical components.

  Conventionally, as means for preventing such electric corrosion, a method of molding a waterproof material such as resin around the connection portion between the terminal and the conductor and embedding the connection portion in the waterproof material (see Patent Document 1), or a terminal For example, there is a method using a waterproof connector in which a housing for housing a waterproof structure is used (see Patent Document 2).

No. 7-29577 Japanese Patent No. 2650051

  However, the method of applying a mold complicates the structure and manufacturing process, requires a large amount of manufacturing equipment, and requires a large amount of resin to be used. In addition, the method using a waterproof connector will not only cause a significant cost increase due to the use of the waterproof connector in the area where the conventional waterproof connector is unnecessary, but if cracks occur due to vibration fatigue or aging, Rainwater or the like enters the connector from the crack, and conversely promotes electrolytic corrosion.

  An object of the present invention is to provide a connecting portion and a connecting method for wires and terminals made of dissimilar metals, which are simple to manufacture, use a small amount of resin, and can be manufactured at low cost.

In order to achieve the above object, according to the present invention, the terminal and the conductor of the electric wire are made of different metals, the conductor caulking portion of the terminal is crimped to the conductor of the electric wire end portion, and the insulation covering caulking portion of the terminal is connected to the electric wire end portion. In the connection portion between the electric wire and the terminal crimped to the insulation coating, the terminal has side walls rising from both sides between the insulation coating caulking portion and the conductor caulking portion and on the tip side of the conductor caulking portion, Cover the exposed conductor portion between the insulation coating caulking portion and the conductor caulking portion between both side walls between the covering caulking portion and the conductor caulking portion, and between the both side walls on the tip side of the conductor caulking portion. A resin is applied so as to cover the exposed conductor portion on the tip side of the caulking portion of the conductor, and the exposed conductor portion is covered with the resin.

  It is preferable that the connection part which concerns on this invention apply | coats resin also to the joint part of a conductor crimping part, and has covered the said joint part with resin.

  Moreover, it is preferable that the connection part which concerns on this invention is the thing whose height of the said side wall of a terminal is the same as or larger than the outer diameter of the insulation coating of an electric wire.

  Moreover, it is preferable that the thickness of the resin apply | coated to the conductor exposed part is the same as that of the insulation coating of an electric wire, or thicker than that.

  In the connecting portion according to the present invention, it is preferable that the adhesive strength between the resin and the terminal is 3 MPa or more, the elastic modulus of the resin is 400 MPa or more, and the water absorption is 5% or less.

  Moreover, it is preferable that the connection part which concerns on this invention is a thing in which the front end surface of a conductor exists in the substantially same position as the front end surface of a conductor crimping part.

  Moreover, it is preferable that the connection part which concerns on this invention is that a conductor of an electric wire consists of aluminum or an aluminum alloy, and a terminal consists of copper or a copper alloy.

Further, according to the present invention, there is provided a method for connecting an electric wire and a terminal made of different metals, wherein the terminal and the conductor of the electric wire are made of different metals, and the conductor caulking portion of the terminal is used as the conductor at the end of the electric wire, and the insulation coating caulking portion of the terminal is used. In the method of connecting the wire and the terminal by crimping to the insulation coating at the end of the wire,
As the terminal, using a terminal having a side wall rising from both sides between the insulation coating caulking portion and the conductor caulking portion and on the tip side of the conductor caulking portion,
Resin is apply | coated to the conductor exposed part between the said side walls, and the joint part of the said conductor crimping part, respectively, and the joint part of a conductor exposed part and a conductor crimping part is covered with resin, It is characterized by the above-mentioned.

  According to the present invention, the conductor exposed portion between the insulation coating caulking portion and the conductor caulking portion of the terminal and the conductor exposed portion on the distal end side of the conductor caulking portion are respectively covered with the resin, so that the contact portion between the terminal and the conductor is covered. Since there is no risk of water, corrosion due to the contact potential difference between the terminal and the conductor can be prevented. In addition, since only the resin is applied to the exposed conductor portion, the manufacturing work is easy, the manufacturing equipment is simple, the amount of resin used is small, and a low-cost anticorrosive connection can be obtained. it can.

  In addition, if resin is also applied to the joint portions of the caulking pieces on both sides of the conductor caulking portion, water can be surely prevented from entering from the joint portions, so that the contact potential difference between the terminal and the conductor in the conductor caulking portion can be prevented. Corrosion can be prevented.

In addition, by using terminals having side walls rising from both sides between the insulation coating caulking part and the conductor caulking part and on the tip side of the conductor caulking part, it is possible to prevent the resin applied to the conductor exposed part from flowing out of the application range. Therefore, the resin coating operation can be easily performed and the thickness of the resin coating film can be secured. When a relatively low viscosity resin having a viscosity of about 5000 to 20000 mPa · s is used, since the resin has high permeability, the height of the side wall is set in consideration of the resin permeability.

  Also, if the height of the side wall of the terminal is equal to or larger than the outer diameter of the insulation coating of the electric wire, the resin can be applied thicker, so that environmental degradation (cracking and cracking) is less likely to occur, and it is highly waterproof. A resin coating film can be easily formed.

  Also, if the thickness of the resin applied to the exposed part of the conductor is equal to or greater than the thickness of the insulation coating of the wire, the resin coating is less susceptible to environmental degradation (cracking and cracking) and has a highly waterproof connection. Can be obtained.

  In addition, if the tip end surface of the conductor is positioned substantially the same as the tip end surface of the conductor caulking portion, the tip end portion of the conductor will not be displaced due to the crimping of the conductor caulking portion. The exposed conductor portion (in this case, the end surface of the conductor becomes the exposed portion) can be more easily and reliably embedded with resin, and a more stable anticorrosive effect can be obtained.

  FIG. 1 shows an embodiment of the present invention. In the figure, reference numeral 1 denotes an electric wire formed by covering a conductor 2 made of an aluminum-based material with an insulating coating 3, and 4 denotes a terminal made of a copper-based material. The terminal 4 has a contact portion 5 with a counterpart terminal on the front end side, and has a conductor caulking portion 6 and an insulating coating caulking portion 7 on the rear end side. The conductor caulking portion 2 is crimped to the conductor 2 exposed at the end portion of the electric wire 1, and the insulating coating caulking portion 7 is crimped to the end portion of the insulating coating 3.

  In this embodiment, the conductor exposed portion 2a between the insulation coating caulking portion 7 and the conductor caulking portion 6 and the conductor exposed portion on the distal end side of the conductor caulking portion 6 in the connecting portion between the electric wire and the terminal made of different metals as described above. The resin 9 is applied to the joint portions 8 of the 2b and the conductor caulking portions 6 and cured, and the conductor exposed portions 2a and 2b and the joint portions 8 are covered with the resin 9. As the resin 9, a silicone-based, acrylic-based, urethane-based, polyamide-based, or epoxy-based resin can be used.

  The terminal 4 has side walls 10, 10, 11, 11 that rise from both sides between the insulating coating caulking portion 7 and the conductor caulking portion 6 and on the leading end side of the conductor caulking portion 6. It is applied so as to cover the exposed conductor portion between 10, 10 and 11, 11. The height h from the terminal bottom surface to the upper end of each side wall 10, 10, 11, 11 is set to be equal to or larger than the outer diameter d of the insulating coating 3 of the electric wire.

  With the configuration as described above, there is no possibility that the contact portion between the terminal 4 and the conductor 2 will get wet, and there is no possibility that water will enter from the joint portion 8 of the caulking portion of the conductor. Corrosion due to potential difference can be prevented. Moreover, since the resin 9 is simply applied to the conductor exposed portions 2a and 2b and the joint portion 8 of the conductor caulking portion, the manufacturing operation is easy, the manufacturing equipment is simple, and the amount of resin used is small. Thus, a low-cost anticorrosion type connecting portion can be obtained. Further, since the resin applied to the exposed conductor portion is restricted from flowing out of the application range by the side walls 10, 10, 11, and 11, the resin application operation can be easily performed and the resin pool can be easily formed. Therefore, the required thickness of the resin coating film can be ensured.

Next, the results of a trial test of the connection part configured as described above will be described. A sample was prepared by applying and curing a resin as shown in FIG. 1 to a connection part obtained by crimping a copper terminal to an aluminum electric wire (0.75 mm ² or more) for an automobile wire harness. A resin having a viscosity of 5000 to 20000 mPa · s at the time of application was used. This viscosity takes into account that when it is applied to the connection part, if it is too fluid, it will flow out and cannot be applied to the desired thickness, and if it is too fluid (too hard) it will not enter a fine gap. This is a very general value. In such a sample, the adhesive strength between the resin and the terminal in the range of −40 ° C. to 125 ° C. after coating and curing, the water absorption rate of the resin after coating and curing, the height h of the side wall of the terminal, the resin coating film Various samples with different thicknesses t were prototyped (the modulus of elasticity of the resin after coating and curing is 400 MPa or more), the resistance value of the connection portion was measured in advance for each sample, and then the next environmental test (accelerated deterioration test) was performed. went.
(1)
High temperature standing: 120 ± 3 ° C, 120 hours standing (2) Salt spray: 35 ± 5 ° C, salt water concentration 5 + 1 mass%, specific gravity 1.0268-1.0413, pH 6.5-7.2 salt water sprayed at 68.6-176.5kPa pressure 96 hours (3) High temperature and high humidity: left for 96 hours at 80 ± 5 ° C. and humidity 90-95% RH

  Table 1 shows the result of measuring the resistance value of the connection portion for each sample after the environmental test. The resistance value was determined to be acceptable if the increase in resistance value after the environmental test was 2.5 mΩ or less compared to the resistance value before the environmental test.

  According to this result, the connecting portion between the electric wire and the terminal has an adhesive strength between the resin and the terminal of 3 MPa or more, a water absorption of the resin of 5% or less, and the height h of the side wall of the terminal is the outer diameter of the insulating coating of the electric wire. As shown in FIG. 3, the thickness t of the resin 9 applied to the exposed conductor portions 2a and 2b is equal to or greater than the thickness of the insulation coating of the electric wire, as shown in FIG. It can be said that it is preferable.

  In the above embodiment, the resin is also applied to the joint portion of the conductor caulking portion. However, when the joint portion of the conductor caulking portion has sufficient water tightness, the application of the resin to this portion is omitted. Is also possible. Resin having a viscosity of 5000-20000 mPa · s has permeability to fine gaps, so that it is possible to obtain a predetermined anti-corrosion property simply by applying it to the exposed part of the conductor without applying it to the joint part. .

  FIG. 2 shows another embodiment of the connecting portion between the electric wire and the terminal according to the present invention. In this embodiment, the tip surface of the conductor 2 is located at the same position as the tip surface of the conductor caulking portion 6. Since the other configuration is the same as that of the embodiment of FIG. 1, the same parts are denoted by the same reference numerals and the description thereof is omitted.

  With such a configuration, the tip end portion of the conductor 2 does not vary due to the crimping of the conductor caulking portion 6, so that the conductor exposed portion on the tip end side of the conductor caulking portion 6 (in this case, the end face of the conductor becomes the exposed portion). ) Can be more easily and reliably embedded with the resin 9, and a more stable anticorrosion effect can be obtained.

(A) which shows one Embodiment of the connection part of the electric wire and terminal which concerns on this invention is a top view, (B) is a side view, (C), (D), (E) is CC of (B), respectively. The expanded sectional view in a line, DD line, and EE line. The top view which shows other embodiment of the connection part of the electric wire which concerns on this invention, and a terminal.

Explanation of symbols

1: Electric wire 2: Conductor 2a made of aluminum material, 2b: Conductor exposed portion 3: Insulation coating 4: Terminal made of copper material 5: Contact portion 6: Conductor caulking portion 7: Insulation covering caulking portion 8: Conductor caulking portion Seam portion 9: Resin 10, 11: Side wall

Claims (8)

The terminal and the conductor of the electric wire are made of different metals, and the electric wire and the terminal are formed by crimping the conductor caulking portion of the terminal to the electric conductor at the end of the electric wire, and crimping the insulating covering caulking portion of the terminal to the insulating coating of the electric wire end portion. The terminal has side walls rising from both sides between the insulation coating caulking portion and the conductor caulking portion and on the leading end side of the conductor caulking portion, and between the insulating coating caulking portion and the conductor caulking portion. conductor exposed portion so as to cover, and the conductor exposed portion of the distal end side of the conductor crimping portion between the distal end side of both side walls of the conductor crimping portion between the insulating coating crimping portion and the conductor crimping portion between the side walls A connecting portion between a wire and a terminal made of a dissimilar metal, characterized in that a resin is applied so as to cover each other, and the exposed portions of the conductor are covered with the resin.   2. A connecting portion between an electric wire and a terminal made of a dissimilar metal according to claim 1, wherein a resin is applied to a joint portion of the conductor caulking portion, and the joint portion is covered with the resin. The height of the side wall of the terminal connecting portion of the electric wire and the terminal consisting of dissimilar metals according to claim 1, wherein the same or larger than the outer diameter of the insulating coating of the wire. The thickness of the resin coated on the conductor exposed portion, the connection portion of the wire and the terminal consisting of dissimilar metals according to any one of claims 1 to 3, wherein the same or the thickness of the insulating coating of the electric wire thicker than . 5. The connecting portion between a wire and a terminal made of a dissimilar metal according to claim 4 , wherein the adhesive strength between the resin and the terminal is 3 MPa or more, the elastic modulus of the resin is 400 MPa or more, and the water absorption is 5% or less.   The connecting portion between the electric wire and the terminal made of a dissimilar metal according to any one of claims 1 to 5, wherein the leading end surface of the conductor is substantially at the same position as the leading end surface of the caulking portion of the conductor. The wire and terminal connecting portion made of a dissimilar metal according to any one of claims 1 to 6 , wherein the conductor of the wire is made of aluminum or an aluminum alloy, and the terminal is made of copper or a copper alloy. The terminal and the conductor of the electric wire are made of different metals, and the conductor caulking portion of the terminal is crimped to the conductor at the end of the electric wire, and the insulating coating caulking portion of the terminal is crimped to the insulating coating of the end of the electric wire to connect the electric wire and the terminal. In the method
As the terminal, using a terminal having a side wall rising from both sides between the insulation coating caulking portion and the conductor caulking portion and on the tip side of the conductor caulking portion,
An electric wire made of a dissimilar metal, wherein a resin is applied to a conductor exposed portion between the side walls and a joint portion of the conductor caulking portion, and the joint portion of the conductor exposed portion and the conductor caulking portion is covered with resin. And terminal connection method.

Images