JP2012101394A - Resin composite molding into which metal terminal is inserted, and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of inexpensively manufacturing a resin composite molding capable of: preventing external influence substance such as moisture or humidity corroding the inner part of an electronic circuit; and having sufficient air tightness with a conventional manufacturing process.SOLUTION: At least one groove shape 9 producing the compression stress of a resin is previously provided in the end part of a metal terminal 1 in the plate width side and has at least a sharp angle structure in which an angle between the groove shape 9 and the metal terminal 1 at the intersection is smaller than 90°. As a result, the metal terminal 1 and the resin 2 are partially tightly closed to each other in the groove shape 9 by utilizing a phenomenon of volume change when the resin 2 solidifies to improve the air tightness.

Description

  The present invention is a resin composite molded body in which a metal terminal is inserted, a part of which protrudes from a resin casing and has an electrical connection portion, and a molded body having a specified amount of airtightness required for practical use. It relates to the manufacturing method.

  A resin composite molded body in which a metal terminal is inserted and a part thereof protrudes from a resin casing and has an electrical connection portion is used in many industrial fields having electronic circuits for various electrical connections such as sensor parts. in use. In particular, in the field of automotive parts, it is used under harsh environmental conditions, so the penetration of external influence substances that corrode the inside of electronic circuits such as moisture and moisture, as well as the durability of the resin part that is the casing. It is necessary to ensure airtightness to prevent.

  However, with the conventional metal terminal insert molding method, due to the solidification process of the molded product and changes in environmental temperature, a minute gap is generated at the interface between the metal terminal and the resin, and sufficient airtightness is ensured. It was difficult. For this reason, a method of roughening the surface of the metal terminal by chemical etching, a method of applying an adhesive around the metal terminal in advance, or an adhesive is applied to a portion where the metal terminal is secondarily exposed after molding, A method of solidifying and ensuring airtightness was adopted.

  Patent Document 1 discloses a method of manufacturing a resin composite molded article in which a metal part is inserted and the metal part protrudes from a resin part, and is made of any one of copper, copper alloy, aluminum, and aluminum alloy in advance. The surface is chemically etched, and then this metal part is inserted into a mold of an injection molding machine, and polyacetal resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polyphenylene sulfide resin, polyamide resin, liquid crystalline polyester resin, polyimide resin, Shinji A metal part characterized by being injection-molded using a thermoplastic resin material mainly composed of at least one kind of resin selected from the group consisting of tactic polystyrene resin and polycyclohexanedimethylene terephthalate resin. Protruding from the resin part That resin / metal interface, method for producing a metal insert resin composite molded article having airtightness is disclosed.

  In Patent Document 2, in an electrode fixing structure in which at least a part of an electrode is embedded in a resin, another resin layer having good adhesion to both of the electrode and the resin is interposed. In a method for forming an electrode fixing structure or an electrode fixing structure in which at least a part of an electrode is embedded in a resin, a resin having good adhesion to both the electrode and the resin is used. A method for forming an electrode fixing structure is disclosed, in which a resin for fixing an electrode is injected around the electrode, and then cured by injecting the resin around the electrode.

Japanese Patent No. 3467471 JP 62-134232 A

  The resin composite molded body that forms part of the electric circuit device is required to be compact in design, so the shape of the metal terminal used for this is naturally complicated, and the electrical contact portion of the terminal has a smooth surface. Is required. Therefore, in the etching method in which the surface of the metal terminal is roughened to improve the airtightness, it is necessary to limit the area to be roughened. Therefore, a process such as a masking process is required for partial roughening. Moreover, in the method of sealing a molded product with an adhesive secondarily, a step of applying and curing the adhesive is required. That is, the target airtightness can be ensured by a known technique of roughening by chemical etching or secondary adhesive sealing, but the manufacturing process becomes complicated and the cost increases.

  In view of such problems, the object of the present invention is to make a resin composite molded article having sufficient airtightness capable of preventing the intrusion of externally affecting substances such as moisture and moisture corroding the inside of an electronic circuit, and making the manufacturing process complicated. It is providing the method of manufacturing cheaply without doing.

  A resin composite molded body in which a metal terminal is inserted and a part thereof protrudes from a resin casing and has an electrical connection portion is manufactured by insert positioning the metal terminal in a molding die and injection molding the resin. Alternatively, a primary molded product in which a metal terminal is pre-molded with a resin is insert-positioned in a molding die and manufactured by a secondary molding method. In any of these manufacturing methods, when the molten resin solidifies in the molding die, a volume change occurs due to the shrinkage of the resin, and there is a minute gap at the interface between the inserted metal terminal and the resin. Occurs.

  In the present invention, at least one groove shape that generates a compressive stress of the resin is provided in advance at the end of the metal terminal on the plate width side, and the angle formed by the groove shape with the plate width side end surface of the metal terminal is 90 °. By adopting a form having at least one acute angle shape smaller than °°, the metal terminal and the resin are partially adhered inside the groove shape by utilizing the phenomenon of volume change when the resin is solidified, thereby achieving airtightness. To improve.

  The groove shape provided in the metal terminal is a shape that can be easily formed when the metal terminal is pressed, and remains in the conventional manufacturing process. Therefore, it is possible to ensure airtightness without increasing the manufacturing cost.

  Moisture that corrodes the inside of an electronic circuit without causing an increase in manufacturing cost by a method of manufacturing a resin composite molded body in which a metal terminal according to the present invention is inserted, a part of which protrudes from a resin casing and has an electrical connection portion It is possible to provide a resin composite molded body having sufficient airtightness that can prevent the intrusion of externally affecting substances such as moisture and moisture at low cost without complicating the manufacturing process.

It is a figure which shows shrinkage | contraction and volume change of resin concerning embodiment of this invention. It is an external view of the sensor cover resin mold product concerning the embodiment of the present invention. It is a detailed view of a sensor cover resin mold product according to an embodiment of the present invention. It is a half section view of the sensor cover resin mold product connector part concerning the embodiment of the present invention. FIG. 3 is a half cut sectional view of a sensor cover resin molded product connector portion, showing a shape according to an embodiment of the present invention. It is a figure which shows shrinkage | contraction and volume change of resin concerning embodiment of this invention. It is a general | schematic half-cut sectional view of the test apparatus used for the airtight evaluation concerning embodiment of this invention. It is an airtightness evaluation test result of the sensor cover resin mold product concerning the embodiment of the present invention. It is an airtightness evaluation test result after the heat cycle test of the sensor cover resin mold product concerning the embodiment of the present invention. It is the groove shape which produces the compressive stress of resin provided in the edge part by the side of the board width of the metal terminal concerning the embodiment of the present invention. It is the groove shape which produces the compressive stress of resin provided in the edge part by the side of the board width of the metal terminal concerning the embodiment of the present invention. It is the groove shape which produces the compressive stress of resin provided in the edge part by the side of the board width of the metal terminal concerning the embodiment of the present invention. It is the groove shape which produces the compressive stress of resin provided in the edge part by the side of the board width of the metal terminal concerning the embodiment of the present invention.

  An embodiment of a resin composite molded body according to the present invention will be described with reference to the drawings.

  FIG. 2 is a cross-sectional view of the appearance of a sensor cover resin molded product and a connector part according to an embodiment of the present invention.

  In FIG. 2, the sensor cover resin molded product 100 has a plurality of metal terminals 1 made of a copper-based alloy material formed by insert molding for the purpose of electrical connection, and one end 3 of the metal terminal 1 is heated. It is an external space of the housing resin portion 2 formed by the plastic resin PBT (polybutylene terephthalate), and is exposed to the space in the connector formed by the housing resin portion 2, and the other end portion 4 is the housing. The resin portion 2 protrudes into the space inside the cover formed and is exposed.

  An electronic circuit board 5 is mounted in the cover internal space formed by the housing resin portion 2, and as shown in FIG. 3, the end 4 where the metal terminal 1 protrudes into the space inside the cover and is exposed, and the electronic circuit board. The joint projection 5a on the base plate 5 is welded and joined by the conductor 6, and constitutes an electronic circuit for transmitting an electrical signal with an external device.

  The sensor cover resin molded product 100 is provided with a rubber seal part 7 at the end of the casing resin part 2 attached to the counterpart part for the purpose of preventing the entry of external influence substances such as moisture and moisture that corrode the inside of the electronic circuit. Equipped with airtightness inside the cover. However, when there are portions protruding and exposed to the inside and outside of the housing resin part 2 such as the end part 3 and the end part 4 of the metal terminal 1, the metal terminal 1 is embedded in the housing resin part 2. When a gap is generated at the interface where the metal terminal 1 and the housing resin part 2 are in contact with each other, sufficient airtightness between the required inside and outside cannot be ensured.

  FIG. 4 is a half cut section of the connector portion of the housing resin portion 2. 4 is a detailed view of the portion A in which the casing resin portion 2 covering the periphery of the metal terminal 1 is contracted and volume-changed predominantly in the lateral direction at the portion surrounded by the portion A in FIG. It is.

  The resin injected into the mold at a high temperature and high pressure is once filled along the metal terminal 1 with no gap. Thereafter, as the resin cools and solidifies in the mold, the resin covering the periphery of the metal terminal 1 contracts and changes in volume, so that a gap 8 is generated at the interface between the metal terminal 1 and the housing resin portion 2. The amount is proportional to the resin volume around the metal terminal 1 under the condition that the molding conditions and the resin composition are constant.

  However, the shrinkage of the resin covering the periphery of the metal terminal 1 has a dominant direction due to the case where the surrounding resin volume is not uniform or due to the anisotropy of shrinkage due to the resin material including the fibrous filler. It is very difficult to control.

  In view of the situation, a groove shape that generates a compressive stress of the resin provided at least at one place is provided in advance at the end of the metal terminal on the width side of the metal terminal by utilizing the phenomenon of volume change when the resin solidifies. Makes the metal terminal 1 and the resin partly in close contact with each other, thereby improving the airtightness. An embodiment of the present invention is shown in FIG.

  The plurality of metal terminals 1 have a groove shape 9 for generating a compressive stress of resin provided at least at one end in advance on the end of the metal terminal 1 on the plate width side. That is, as shown in the detailed view of part B, this groove shape 9 has at least one acute angle shape 11 in which the angle 10 formed at the intersection with the end face of the metal terminal 1 on the plate width side is smaller than 90 °. According to this embodiment, in the depth direction of the groove shape 9, the groove shape 9 is formed so that the depth side in the depth direction widens the groove shape in the longitudinal direction of the metal terminal with respect to the inlet side end portion of the groove shape 9. Has been. Alternatively, the side wall surface on the inlet side protrudes toward the inside of the groove with respect to the side wall surface on the back side in the depth direction, in other words, the side wall surface on the back side in the depth direction is recessed with respect to the side wall surface on the inlet side. A groove shape 9 is formed in a shape that is recessed so as to form. Further, the tensile stress generated in the narrow portion of the resin filled in the groove shape is applied to the groove shape end portion (on the intersection of the plate width side end surface and the groove shape or on the intersection line of the plate width side end surface and the groove shape). It has a corner R12 intended to be dispersed in an R shape, and can be easily molded by press working. FIG. 1 shows the shrinkage change of the resin when the metal terminal 1 subjected to the groove processing is inserted into a molding die and injection molded.

  The left side of FIG. 1 shows a state in which a shrinkage change in which the left direction is dominant occurs in the left housing resin portion 2a covering the periphery of the metal terminal 1, and the right side of FIG. The state when the shrinkage | contraction change which made the down direction dominant was produced in the right side housing | casing resin part 2b which covers the circumference | surroundings is shown. The resin injected into the mold at a high temperature and high pressure is once filled along the metal terminal 1 with no gap. Thereafter, as the resin cools and solidifies in the mold, the resin covering the periphery of the metal terminal 1 contracts and changes in volume, so that a gap 8 is generated at the interface between the metal terminal 1 and the housing resin portion 2. However, in the resin filled and filled in the groove shape 9 forming the acute angle shape 11 provided in the metal terminal 1, in any case, at least one surface of the acute angle shape 11 provided in the metal terminal 1 Since the shrinkage behavior acts in a direction that generates a compressive stress in a direction perpendicular to the surface of the acute angle shape 11, the seal portion 13 that partially blocks the interface gap 8 is formed. Accordingly, airtight leakage from both side surfaces of the metal terminal 1 in the plate width direction is eliminated, and airtightness is improved.

  Furthermore, as an effect brought about by the groove shape 9, there is a reduction in airtight leakage on the plate thickness direction side. That is, by providing the groove shape 9, the length of the interface gap generated by the region of the depth dimension 15 of the groove shape 9 is reduced from the plate width 14 of the metal terminal 1, thereby enabling airtight leakage on the plate thickness side. This is because the interface cross-sectional area 16 decreases and the pressure loss of the leaking fluid increases. Therefore, it is desirable that the depth dimension 15 of the groove shape 9 is larger, but considering the rigidity of the metal terminal 1 and the processing limit of press working, a value obtained by subtracting the value of the plate thickness 17 from the plate width 14 of the metal terminal 1. A smaller value is desirable.

  With the shrinkage change of the housing resin portion 2 shown in FIG. 1, a compressive stress corresponding to the molding shrinkage rate of the housing resin portion 2 is applied to the seal portion 13 unless an external force acts on the metal terminal 1. Furthermore, it is predicted that the value fluctuates as the environmental temperature changes. That is, a distortion corresponding to the molding shrinkage rate is generated in the resin portion of the seal portion 13 at room temperature, and the value changes as the environmental temperature changes. However, considering the thermal expansion difference between the metal and the resin, the expansion rate on the resin side is large, and the seal portion 13 is not opened and the gap does not change, so that the desired airtightness is ensured.

  On the other hand, in the present invention, it is necessary to consider the creep destruction specific to the resin. That is, as shown in detail in FIG. 5B, the groove shape 9 that generates the compressive stress of the resin provided at least at one end on the plate width side of the metal terminal in advance is the same as the groove shape 9 with the plate width side end surface of the metal terminal. In addition to the form having at least one acute-angle shape 11 whose angle formed at the intersection is smaller than 90 °, the groove-shaped end portion is subjected to tensile stress generated in the narrow portion of the resin filled in the groove shape 9, The corner R12 intended to be distributed in an R shape, and the groove width 18 (see FIG. 6) on the plate width end face side of the metal terminal 1 are the thickness of the metal terminal 1 shown in section CC in FIG. It is important that the tensile stress generated in the narrow portion of the resin filled in the groove is dispersed in the resin cross-sectional area by setting the dimension larger than 17 (preferably 1.5 times or more).

  As shown in FIG. 6, the end value (groove width) 18 of the groove width provided in the metal terminal 1 needs to be set in consideration of the form of the resin covering the periphery of the metal terminal 1. That is, when shrinkage toward the longitudinal shrinkage center 19 of the resin filled in the groove shape 9 becomes dominant, the interfacial gap 8 is formed on the entire inner surface of the groove shape 9, so that the volume balance can be avoided. Therefore, it is important to set the dimensions in consideration of the thickness dimension 17 of the metal terminal 1 to be used and the characteristics of the resin material to be used.

  In the above embodiment, a sensor cover resin molded product of a metal terminal provided with a groove shape according to the present invention and a grooveless metal terminal according to the present invention was manufactured, and the airtightness was measured using the test apparatus shown in FIG. The evaluation results are described below.

  The sensor cover resin molded product 100 is positioned and set on the jig 20 fixed on the test apparatus, and the sensor cover resin molded product 100 is formed in such a manner that the entire circumference is in close contact with the inner space upper end surface 21 of the sensor cover resin molded product 100 and has a sealing property. The jig 23 to which the fixed rubber component 22 is mounted and fixed is pressure-fixed with a pressure of 120 N. Then, after reducing and stabilizing the internal space 24 of the sensor cover resin molded product 100 at a pressure of 70 kPa, measurement of the internal pressure is started, and the amount of leakage per specified time is determined by the amount of change and the volume of the internal space 24. evaluated.

  As a result, as shown in the test results shown in FIG. 8, when the leakage amount average of the sensor cover resin molded product (n = 3) using the metal terminal having no groove shape is 1, the groove shape 9 according to the present invention is provided. In the sensor cover resin molded product using a metal terminal, a leakage reduction of 35% to 45% was confirmed.

  Next, FIG. 9 shows the results of a heat cycle resistance test using the same sensor cover resin molded product. The evaluation conditions are -58 ° C. (1 hr) to 150 ° C. (1 hr) in one cycle (1 cycle = 4 hr), the resin composite molded body is taken out from the tank every 42 cycles, and the above airtightness test is performed up to 400 cycles. Went. As a result, no increase in leakage occurred in the total number of evaluation products, and it was confirmed that the resin composite molded body obtained by the production method of the present invention can maintain excellent airtightness even in a harsh environment.

  The sensor cover resin mold product of the above example inserts a metal terminal using a copper-based alloy material, and uses a PBT (polybutylene terephthalate) resin for the resin casing part. The resin material is not limited to this, and can be arbitrarily selected. Further, unless departing from the gist of the present invention, the form of the groove shape 9 that generates the compressive stress of the resin provided at least at one end in advance on the plate width side of the metal terminal is not limited to this. As shown in FIG. 10, the metal terminal has a relatively wide plate width dimension, and the relationship between the depth dimension 15 of the groove shape 9 and the plate thickness 17 allows press working. The groove shape 9 may be arranged at a position to be. Further, as shown in FIG. 11, if the angle 10 formed at the intersection of the acute angle shape 11 forming the groove shape 9 and the end face of the metal terminal is at least one acute angle shape smaller than 90 °. The angle formed by the groove 9 on the other side may be a right angle or an obtuse angle greater than 90 ° as shown in FIG. Further, the number of the groove shapes 9 provided in one metal terminal may be plural as shown in FIG.

  According to each of the above embodiments, it is only necessary to change the shape of the metal terminal formed by pressing, so there is no need to add a new process as it is in the conventional manufacturing process, and moisture and moisture that corrode the inside of the electronic circuit. A resin composite molded body having sufficient airtightness that can prevent the intrusion of an externally affecting substance such as the like can be produced at low cost.

  The plate pressure direction is a direction punched in the press working, and the plate width direction is a direction substantially perpendicular to the plate pressure direction.

DESCRIPTION OF SYMBOLS 1 Metal terminal 2 Housing resin part 3, 4 One end of metal terminal 5 Electronic circuit board 5a Joining protrusion 6 Conductor 7 Rubber seal part 8 Interfacial gap 9 Groove shape 10 Angle which groove shape makes | forms the intersection with the board width side end surface 11 Sharp corner shape 12 Corner R
13 Seal portion 14 Plate width dimension 15 of metal terminal 15 Depth dimension 16 from end face of groove shape 9 Interface cross-sectional area 17 Plate thickness dimension 18 of metal terminal End groove width dimension 19 Longitudinal contraction center 20, 23 Test jig 21 Internal space upper end surface 22 Rubber component 24 Internal space 100 Sensor cover resin molded product

Claims (10)

In the method of manufacturing a resin composite molded body in which a metal terminal is inserted, and a metal terminal is inserted, part of which protrudes from the resin casing to form an electrical connection portion.
At least one groove shape that generates a compressive stress of the resin is provided in advance at the end portion on the plate width side of the metal terminal, and the angle formed by the groove shape with the plate width side end surface of the metal terminal is an acute angle smaller than 90 ° A metal terminal having a shape having at least one shape, wherein the metal terminal and the resin are partially adhered inside the groove shape by utilizing a phenomenon of volume change when the molten resin is solidified. A method for producing a resin composite molded body with inserts. In the manufacturing method of the resin compound molded object which inserted the metal terminal of Claim 1,
An R shape is formed at the intersection of the plate width side end face of the metal terminal and the groove shape, and the tensile stress generated in the narrow portion of the resin filled in the groove shape is dispersed in the R shape. A method for producing a resin composite molded body with inserts. In the manufacturing method of the resin compound molded object which inserted the metal terminal of Claim 1,
The metal terminal is characterized in that the groove width on the end face side of the plate width of the metal terminal is set larger than the thickness of the metal terminal plate, and the tensile stress generated in the narrow portion of the resin filled in the groove is dispersed by the resin cross-sectional area. Manufacturing method of inserted resin composite molded body. In the manufacturing method of the resin compound molded object which inserted the metal terminal of Claim 1,
The resin composite in which the metal terminal is inserted, wherein the depth dimension of the groove shape from the plate width end surface side of the metal terminal is smaller than the value obtained by subtracting the plate thickness from the plate width of the metal terminal. Manufacturing method of a molded object. In the manufacturing method of the resin compound molded object which inserted the metal terminal of Claim 1,
The method for producing a resin composite molded body having a metal terminal inserted therein, wherein the groove shape is a form in which an interface cross-sectional area capable of airtight leakage on the plate thickness side of the metal terminal is reduced. In a resin composite molded body in which a metal terminal is inserted and a part of the metal terminal protrudes from a resin casing to form an electrical connection portion,
At the end of the metal terminal on the plate width side, there is a groove shape that generates a compressive stress of the resin provided in at least one place, and the angle formed by the groove shape with the intersection of the metal terminal with the plate width side end surface is from 90 ° A resin composite molded body having a metal terminal inserted therein, wherein the resin composite molded body has at least one small acute angle shape. In the resin composite molded body in which the metal terminal according to claim 6 is inserted,
A resin composite molded body having a metal terminal inserted therein, wherein an R shape is formed at the intersection of the plate width side end face of the metal terminal and the groove shape. In the resin composite molded body in which the metal terminal according to claim 6 is inserted,
A resin composite molded body having a metal terminal inserted therein, wherein the groove width on the plate width end face side of the metal terminal is set larger than the thickness of the metal terminal plate. In the resin composite molded body in which the metal terminal according to claim 6 is inserted,
The resin composite in which the metal terminal is inserted, wherein the depth dimension of the groove shape from the plate width end surface side of the metal terminal is smaller than the value obtained by subtracting the plate thickness from the plate width of the metal terminal. Molded body. In the resin composite molded body in which the metal terminal according to claim 6 is inserted,
The resin composite molded body having a metal terminal inserted therein, wherein the groove shape is a form that reduces an interface cross-sectional area capable of airtight leakage on the plate thickness side of the metal terminal.

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