JP2006123458A - Manufacturing process of waterproof connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing process of a waterproof connector exhibiting a very high waterproofness, even when a wire is used having a cover layer made of an olefinic resin which is produced in an productive, easy and trouble-free manner at a low cost and involves no fear of emission of toxic gases such as dioxins on ignition. <P>SOLUTION: In a manufacturing process of an integrated waterproof connector in which the waterproof part is formed by insert molding using a covered wire connected with a terminal metal piece as an insert, the connector forming part of the covered wire is subjected to corona discharge or plasma discharge treatment, an adhesive is applied to the treated part and insert molding is made. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a waterproof connector.

  In automobiles, the required electric capacity is increasing more and more, such as the mounting of electronic devices such as navigation systems becomes normal. In this way, as the circuit current and voltage increase, the vehicle wire harness, connector, and the like are rather required to be lighter and smaller, and to be improved in waterproof function.

  Here, when the waterproof connector is manufactured, if a wire (wire bundle) having a polyolefin-based coating is used, the housing material and the coating material can be used even when integrally manufactured by insert molding. Insufficient adhesion at the interface may cause water leakage (water permeation), contact failure or corrosion at contacts inside the connector, or problems such as short circuits. In order to prevent such an unexpected problem of the waterproof connector, several countermeasures have been proposed for the case of integrally manufacturing by insert molding and the case of not using the insert molding method.

That is,
1. A method of providing a special water stop structure for the wire terminal (Japanese Patent Laid-Open No. 2002-315130 (Patent Document 1))
2. A method of using a silicone rubber stopper and packing (Japanese Patent Laid-Open No. 9-65517 (Patent Document 2),
3. A method of filling a resin filler between a connector housing and an electric wire (Japanese Patent Application Laid-Open No. 2004-119047 (Patent Document 3), and
4). For example, the housing part is formed by insert molding by injection molding to eliminate a gap between the terminal fitting / wire and the housing (Japanese Patent Laid-Open No. 10-247547 (Patent Document 4)).

However,
-In the case of an olefin-coated electric wire, the adhesive force at the interface between the electric wire and the mold housing is inadequate and cannot withstand the waterproof evaluation performed under pressure (4. above),
-Productivity and workability are poor, time-consuming and costly (above 1. to 3.)
-Adhesiveness sufficient for olefin-coated wires cannot be obtained (3. above),
-The volume increases, making it difficult to reduce the size and weight (1. to 3. above).
-Commercial adhesives and fillers cannot be expected to improve adhesion to olefinic materials (3. and 4. above),
Such problems arise.
JP 2002-315130 A JP-A-9-65517 JP 2004-119047 A Japanese Patent Laid-Open No. 10-247547

  The present invention is a method for manufacturing an integrated waterproof connector that performs insert molding using a covered electric wire connected with a terminal fitting as an insert to form a waterproof connector portion, and has good productivity and workability, and does not require labor. A method for manufacturing a waterproof connector that is very waterproof and has a very high waterproof property even when using an electric wire having a coating layer made of an olefin-based resin that is low in cost and does not generate harmful gases such as dioxins even when burned. The purpose is to provide.

  In order to solve the above-described problem, the waterproof connector manufacturing method of the present invention, as described in claim 1, forms a waterproof connector portion by performing insert molding using a covered electric wire connected with a terminal fitting as an insert. In the method for manufacturing a connector, the connector forming portion of the covered electric wire is subjected to corona discharge treatment or plasma discharge treatment, an adhesive is applied to the processing portion, and then insert molding is performed.

  According to the method for producing a waterproof connector of the present invention, the productivity and workability are good, the labor is not required, the cost is low, and no harmful gas such as dioxins is generated during combustion. Even when an electric wire having a coating layer made of resin is used, a waterproof connector with extremely high waterproof properties can be obtained.

  In the present invention, the covered electric wire to which the terminal fitting is connected is only required that the conductor of the covered electric wire and the terminal fitting are electrically connected. Such connection includes crimping, caulking, brazing, soldering, etc. Normal connection means can be mentioned.

  In a covered electric wire to which a terminal metal fitting as an insert is connected, a part of the connector part is formed on at least a part of the surface of the covering layer, and a corona is formed in that part of the covering layer, that is, the connector forming part of the covered electric wire. It is necessary to perform discharge treatment or plasma discharge treatment.

  By such corona discharge treatment or plasma discharge treatment, the surface of the coating layer is modified, and waterproofness is improved. In the surface modification, either corona discharge treatment or plasma discharge treatment is performed, but both may be performed. Plasma discharge is performed when uniformity of surface modification is required.

  In addition, since the adhesive is not washed away by the injected resin at the time of insert molding described later, the processing conditions such as the discharge processing time and power are adjusted to further improve the adhesive force between the adhesive and the coating layer surface. deep. For generation of plasma, a high frequency of 500 to 10,000 Hz, an RF wave, and a microwave are used. The pressure can be used from vacuum to atmospheric pressure.

  As the plasma generating gas, an inert gas such as helium or argon, oxygen, nitrogen or the like can be used alone, or a mixture of these gases can be used.

  Thus, it is necessary to apply | coat an adhesive agent to the connector formation part of the covered electric wire which performed the discharge process so that sufficient waterproofness may be acquired. As the adhesive used, it is desirable to use a room-temperature drying type adhesive in order to place importance on workability. Further, since the adhesive may flow due to the resin flow during insert molding, the viscosity is high. It is desirable to use an adhesive. Such a thing is available from Cemedine. The application amount of such an adhesive is preferably 50 μm or more and 200 μm or less because the cost is low and sufficient adhesive strength is obtained.

  A waterproof connector is formed by insert molding using a covered electric wire to which a terminal fitting coated with an adhesive is applied as part of a coating layer such as corona discharge treatment or plasma discharge treatment. The waterproof connector to be used may be a one-terminal type (having one terminal) or a multi-terminal type (having a plurality of terminals).

  The connector portion is formed in the same manner as the manufacturing method of a normal integrated waterproof connector in which a waterproof connector portion is formed by insert molding using a covered electric wire connected with a terminal fitting as an insert. The resin used at this time is also a resin used for normal connector portion formation, that is, a nylon (polyamide) resin.

  Here, an example of the manufacturing method of the waterproof connector of the present invention will be described with reference to a model diagram. As shown in FIG. 1A, the covering layer 1b at the tip of the covered electric wire 1 is removed so that the conductor can be seen. Next, plasma discharge treatment is performed on the connector forming portion of the covered electric wire as indicated by an arrow (see FIG. 1B).

  As shown in FIG.1 (c), the adhesive agent 2 is apply | coated to the coating layer surface which performed the plasma discharge process (The solvent of the adhesive agent 2 is fully volatilized after application | coating). Next, the terminal fitting 3 is soldered to the leading end of the conducting wire 1a (see FIG. 1 (d)).

  The covered electric wire to which the terminal metal fittings obtained in this way are connected is set in the mold 4 as an insert (see FIG. 1 (e)), resin is injected into the cavity 4a in the mold 4 and insert molding is performed. Then, a connector part 5 (waterproof connector part) having a resin part 5a (model sectional view shown in FIG. 1 (f)) is formed. At this time, since the adhesion between the resin portion 5a and the surface of the coating layer 1b of the electric wire is very high due to the plasma discharge treatment and the adhesive, extremely high waterproofness is obtained. A screw fixing hole 5b for fixing the connector is provided near the end of the terminal fitting.

  As described above, the base portion of the waterproof connector portion of the waterproof connector according to the present invention has a coating layer, an adhesive layer, and a waterproof connector portion, which are subjected to plasma discharge treatment or corona discharge treatment on the surface, in this order. Is formed.

  Examples of the present invention will be specifically described below. Using a 13.56 MHz RF wave power source (100 W), oxygen plasma was generated between two plate electrodes arranged in parallel so that the distance between the electrodes was 40 mm.

  A connector forming part of a covered electric wire having a covering layer made of polyethylene was put between these electrodes, and plasma discharge treatment was performed by irradiating oxygen plasma for 30 seconds.

  Next, a commercially available adhesive (Super Med Black manufactured by Cemedine Co.) was applied to the part subjected to the plasma discharge treatment. Thereafter, a terminal fitting was crimped to the conductor of the covered electric wire, and then nylon 66 resin was injected to perform insert molding to obtain an integrated waterproof connector (Example 1).

  The obtained waterproof connector was subjected to a seal test to evaluate its waterproof function. Specifically, FIG. 2 is a model diagram showing the waterproof function evaluation.

  The produced waterproof connector (Example 1) was set in a tester, and the cut surface of the covered electric wire was sealed with a sealant. Air is blown into this tester, and the pressure is increased up to 200 kPa. Check whether there is air leakage from the contact part (shown with the arrow down in the figure) between the molded waterproof connector terminal and the covered wire. Examined.

  At the same time, two types of waterproof connectors produced under the two conditions of no plasma treatment / adhesive application (Comparative Example 1) and no plasma treatment / adhesive application (Comparative Example 2) are similarly applied. The waterproof property was evaluated. The results are shown in Table 1 (“◯” in Table 1 indicates the case where there was no air leakage at each pressure, and “X” indicates the case where there was air leakage).

  From Table 1, it can be seen that the waterproof connector according to the present invention provides excellent waterproof properties. In addition, the waterproof connector according to the present invention, which was confirmed to have excellent waterproof performance as described above, was subjected to a thermal durability test at 150 ° C. for 300 hours, and then was similarly evaluated for waterproofness again. It was confirmed that no leakage occurred.

  Since the waterproof connector portion according to the present invention has extremely high waterproof performance, it can be suitably applied to electrical connection-related uses such as automobiles, motorcycles, outdoor wiring, and the like that require high waterproof properties.

It is model explanatory drawing which shows an example of the manufacturing method of the waterproof connector of this invention. (A) It is a figure which shows the state which removed the coating layer 1b of the front-end | tip part of the covered electric wire 1, and made the conducting wire visible. (B) It is a figure which illustrates the location which performs the plasma discharge process of the connector formation part of a covered electric wire. (C) It is a figure which shows the location of the coating layer surface which performed the plasma discharge process which apply | coats the adhesive agent 2. FIG. (D) It is a figure which shows the state which soldered the terminal metal fitting 3 to the front-end | tip of the conducting wire 1a. (E) It is a figure which shows the state (model sectional drawing) set to the metal mold | die 4 by using the covered electric wire to which the terminal metal fitting was connected as an insert. (F) It is a model cross section which shows the waterproof connector part 5 obtained. It is model sectional drawing for demonstrating the waterproof evaluation method of the waterproof connector part based on this invention obtained in the Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Covered electric wire 1a Conductor 1b Cover layer 2 Adhesive 3 Terminal metal fitting 4 Mold 4a Cavidy 5 Waterproof connector part 5a Resin molding part 5b Screw hole

Claims (1)

  In the manufacturing method of the integrated waterproof connector that performs insert molding using the covered electric wire to which the terminal fitting is connected as an insert to form the waterproof connector portion, the connector forming portion of the covered electric wire is subjected to corona discharge treatment or plasma discharge treatment, A method of manufacturing a waterproof connector, wherein insert molding is performed after an adhesive is applied to the processing portion.

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