JP2006142513A - Insert molded product and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To eliminate a sealing process after insert molding. <P>SOLUTION: A nut 30 (insert member) made of a metal is held to a holding member 80 made of a synthetic resin and the holding member 80 is fitted in a lower mold 71 to be set to a positioning state while the lower mold 71 is filled with a molten resin to mold a function part 20 (resin molded member) having a form which covers the nut 30 and the boundary part of the nut 30 and the holding member 80. After insert molding, the whole of the nut 30 made of the metal is embedded in the function part 20 and the nut 30 and the boundary part of the nut 30 and the holding member 80 are also embedded in the function part 20. Accordingly, the boundary part of the metal member and the resin member are not exposed to the outside and a process for sealing the boundary part of the metal member and the resin member is eliminated. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an insert molded product and a method for manufacturing the same.

2. Description of the Related Art Conventionally, an electronic control unit that accommodates a printed circuit board on which an electronic control circuit is mounted in a synthetic resin case, various electronic components, and the like and is attached to a vehicle body is known. The structure of the part that forms the ground path in this type of electronic control unit is described in Patent Document 1 below.
In order to manufacture this electronic control unit, first, a metal nut that can be connected to the ground wire from the electronic control circuit and a metal collar that is fitted in the mounting hole of the case are in contact with the relay bus bar, respectively. Attach to the mold. Then, a case is formed by insert molding using these as inserts, so that a metal nut, a relay bus bar, and a metal collar are embedded in order. Therefore, if the ground wire is connected to the metal nut and the case is fixed to the body, the ground wire is electrically connected to the body via the metal nut, the relay bus bar, and the metal collar, and the ground is taken. It is assumed that
JP 2004-40945 A

By the way, in the above case, when the metal nut is set in the mold, the bottom of the metal nut is positioned and held by the presser pin protruding from the mold. However, according to this method, a pin hole resulting from the pulling out of the presser pin remains below the bottom of the nut, and the metal nut is exposed in the pin hole. In general, a metal and a synthetic resin have low affinity, and it is difficult to maintain airtightness at the boundary between the metal and the synthetic resin. Therefore, after insert molding, in order to ensure the airtightness of the boundary portion with the metal nut in the pin hole, a sealing process for closing the pin hole by performing potting with a synthetic resin material is necessary. .
This invention is completed based on the above situations, Comprising: It aims at making the sealing process after insert molding unnecessary.

  As a means for achieving the above object, the invention of claim 1 is capable of holding a metal insert member and the insert member, and enabling fitting in a positioning state with respect to a mold. A synthetic resin holding member; and a resin molded member formed by filling the molten resin in a state where the holding member holding the insert member is fitted and positioned in the mold. The resin molded member is characterized in that the insert member and a boundary portion between the insert member and the holding member are covered.

  According to a second aspect of the present invention, in the first aspect of the present invention, the contact surface between the holding member and the resin molded member is uneven from the exposed position of the holding member on the outer surface of the resin molded member toward the back. It is characterized in that a non-smooth part in a form in which the lines are arranged is formed.

  According to the invention of claim 3, the metal insert member is held by a synthetic resin holding member, and the holding member is fitted into a mold to be positioned, and the mold is filled with molten resin. By this, it has the characteristics in the point which shape | molds the resin molded member of the form which covers the boundary part of the said insert member and the said insert member, and the said holding member.

<Invention of Claims 1 and 3>
By using the holding member, the insert member can be positioned with respect to the mold. In addition, after the insert molding, all the metal insert members are embedded in the resin molded member, and the boundary portion between the insert member and the synthetic resin holding member is also embedded in the resin molded member. Therefore, a step for sealing the boundary portion between the metal member and the resin member is not required.

<Invention of Claim 2>
In the unlikely event that liquid enters the gap between the outer surface of the resin molded member and the holding member, the liquid intrusion route is detoured and extended by the non-smooth part, It is possible to suppress intrusion.

<Embodiment 1>
A first embodiment of the present invention will be described below with reference to FIGS. The present embodiment shows an example when applied to an electronic control unit, and the structure thereof will be described below.
As shown in FIG. 1, the electronic control unit includes a case 10 made of synthetic resin. The case 10 is formed in a box shape having an open upper surface, and accommodates an electrical component 12 such as a board connector or a capacitor to be connected while the printed board 11 is placed thereon. The case 10 is attached to a body (not shown) after being covered with a cover (not shown).

  A functional part 20 (resin-molded member which is a constituent element of the present invention) is provided on one side wall of the peripheral wall of the case 10 so as to protrude laterally, and the functional part 20 has a connection between two conductors. A nut 30 for fastening (a metal insert member which is a constituent element of the present invention) is embedded. One of the conductors is constituted by a terminal fitting 40 connected to the end of the electric wire W extending from the outside of the case 10, and the other one is constituted by a bus bar 80 extending from the inside of the case 10.

  The nut 30 is formed of a metal elongated cap nut, and is provided in a pair of sideways and right and left in a vertical posture with the opening portion facing upward in the function unit 20. A holding member 80 made of synthetic resin having a bottomed cylindrical shape that is in close contact with the outer peripheral surface and the bottom surface thereof is fixed to the lower end portion of the nut 30. A positioning projection 81 having a cylindrical shape concentric with the holding member 80 is integrally formed at a central position on the bottom surface (lower end surface) of the holding member 80 so as to protrude downward. The positioning protrusion 81 is formed with a positioning hole 82 that is recessed so as to open to the lower end surface thereof and to form a concentric circle with the positioning protrusion 81. Further, a plurality of ridges that are concentric with the positioning protrusion 81 and have different diameters are formed in the peripheral area (annular area) of the positioning protrusion 81 on the lower end surface of the holding member 80. A non-smooth portion 83 is formed in a form in which the projections 81 are continuously arranged in the direction of the outer periphery of the holding member 80.

  The functional unit 20 covers the periphery of the nut 30 in a form that exposes the opening at the upper end thereof, and surrounds the entire area of the outer peripheral surface of the holding member 80 and the positioning protrusion 81 on the lower end surface of the holding member 80. A first cylindrical portion 21 that covers the annular region and the entire region of the outer peripheral surface of the positioning projection 81 is provided for each nut 30. The first cylindrical portion 21 also covers the boundary portion between the inner peripheral surface of the holding member 80 and the outer peripheral surface of the nut 30 at the upper end portion of the holding member 80. Further, the lower end surface of the positioning projection 81 and the positioning hole 82 are exposed at the lower end surface of the first cylindrical portion 21.

  Similarly, in the function portion 20, a pair of second cylinder portions 22 each having a through hole 23 for insertion of a male screw that is integrally connected to the first cylinder portion 21 and communicates with the opening of the nut 30 corresponds to each nut 30. A third cylinder portion 24 provided with an insertion hole 25 for insertion of a terminal fitting that is provided integrally with the first cylinder portion 21 and the second cylinder portion 22 and leads to the opening of the nut 30 is provided for each nut 30. Correspondingly, a pair is provided. As described later, the terminal fitting 40 is inserted into the insertion hole 25 of the third cylindrical portion 24, and the tip thereof faces the opening of the nut 30.

  The second cylinder part 22 is arranged vertically and opens upward, while the third cylinder part 24 is arranged sideways and opens sideways and extends substantially vertically in the second cylinder part 22. The hole 23 and the insertion hole 25 extending substantially horizontally in the third cylindrical portion 24 communicate with each other so as to intersect at a substantially right angle on the opening of the nut 30. The adjacent second cylindrical portions 22 are integrally joined at their end portions, and a plurality of ribs 26 are erected on the outer peripheral surface of the third cylindrical portion 24 at intervals in the circumferential direction. One of the ribs 26 </ b> A is installed substantially horizontally between the adjacent third cylindrical portions 24.

  After the male screw 50 is inserted into the through hole 23 of the second cylindrical portion 22, a substantially cylindrical rubber plug 60 is fitted. A plurality of lips 61 are provided in the circumferential direction on the outer peripheral surface of the rubber plug 60, and the through holes 23 are sealed by the lips 61 being in close contact with the inner wall of the through holes 23. A step portion 23A is provided in the middle of the inner wall of the through hole 23 in the height direction, and a rubber plug 60 can be placed on the step portion 23A.

  The terminal fitting 40 inserted into the insertion hole 25 of the third cylinder portion 24 is formed by bending a metal plate or the like, and is caulked to the core wire portion exposed at the end of the electric wire W, and the tip thereof And a connection main body 42 arranged in a flat and substantially horizontal manner. The distal end of the connection main body 42 has an annular shape that faces the opening of the nut 30 and allows the shaft 51 of the male screw 50 to be inserted into the nut 30. On the other hand, the bus bar 80 to which the terminal fitting 40 is to be connected has an annular shape that allows one end of the bus bar 80 to face the opening of the nut 30 and allow the insertion of the shaft portion 51 of the male screw 50 to the nut 30 side, and the other end thereof. It is arranged in the case 10 so that it can be connected to the conductor path of the printed circuit board 11, and an intermediate part thereof is embedded in the case 10. One end portion of the bus bar 80 and the tip end portion of the connection main body portion 42 are vertically overlapped on the opening of the nut 30, and the shaft portion 51 of the male screw 50 can be inserted into the hole portion communicating with the nut 30. It is said.

  A seal member 90 is fitted around the sheath of the electric wire W behind the terminal fitting 40. The seal member 90 is formed in a cylindrical shape, and the electric wire W can be tightly penetrated inside. A plurality of (two in the illustrated case) lips 91 are provided in the circumferential direction on the outer peripheral surface of the seal member 90, and these lips 91 are in close contact with the inner wall of the insertion hole 25, thereby sealing the insertion hole 25. .

Next, the manufacturing method of this embodiment is demonstrated.
First, a mold for insert molding will be described. That is, as shown in FIG. 4, this mold molds the upper mold 70 for molding the second cylinder part 22 and the third cylinder part 24, and the first cylinder part 21 and the third cylinder part 24. A lower die 71 for holding the nut 30 and the holding member 80 and a slide die 72 that can move substantially horizontally to the side and form the insertion hole 25 of the third cylindrical portion 24 are provided. The upper die 71 is provided with a support pillar 73 for forming the through hole 23 of the second cylindrical portion 22 so as to protrude downward. Formed in the lower mold 71 is a form in which a molding hole 74 for molding the outer peripheral surface and the lower end surface of the first cylindrical portion 21 is opened upward. A circular fitting projection 75 for fitting the positioning hole 82 of the holding member 80 is formed on the bottom surface of the forming hole 74 so as to protrude upward.

  In order to insert-mold the functional unit 20 using the above-described mold, first, as shown in FIG. 3, the lower end of the nut 30 is fitted into the holding member 80 without backlash. The nut 30 is held. Next, the holding member 80 holding the nut 30 is set in the lower mold 71, and the positioning hole 82 is fitted to the fitting protrusion 75 without backlash. As a result, the holding member 80 and the nut 30 are positioned at predetermined positions in the lower mold 71. At this time, the metal nut 30 does not come into direct contact with the lower mold 71. The bus bar 80 is positioned with respect to the upper mold 70 or the lower mold 71, and one end of the bus bar 80 is overlapped with the upper end surface of the nut 30.

  After setting the nut 30, the holding member 80 and the bus bar 80 to the lower mold 71 in this way, the slide mold 72 is moved to the molding position and the upper mold 70 is lowered to close the mold. The molten resin is injected and filled into the cavity 77. After the synthetic resin is cooled and solidified, the mold is opened. Then, the second cylinder part 22 is removed from the upper mold 70 and the support pillar 73, and the third cylinder part 24 is removed from the upper mold 70 and the slide mold 72, so that the entire case 10 including the functional part 20 is removed. Can be removed from the mold. Thereafter, when the molded product is lifted upward and removed from the lower mold 71 while removing the holding member 80 from the fitting protrusion 75, the case 10 is obtained. Thus, the insert molding is completed.

  Thereafter, the terminal fitting 40 connected to the end of the electric wire W is inserted into the insertion hole 25 of the second cylindrical portion 22 together with the seal member 90, and the distal end portion of the connection main body portion 42 of the terminal fitting 40 is connected to one end of the bus bar 80. The terminal fitting 40 and the bus bar 80 are connected to the head 52 of the male screw 50 and the nut by inserting the male screw 50 through the opening of the through hole 23 and screwing the shaft 51 of the male screw 50 to the nut 30. 30 and fixed in the thickness direction. Thereby, the terminal metal fitting 40 and the bus bar 80 are electrically connected. After this screwing is completed, a rubber plug 60 is fitted into the through hole 23 of the second cylindrical portion 22, and the through hole 23 is sealed in a liquid-tight manner. Further, the insertion hole 25 of the third cylinder portion 24 is sealed in a liquid-tight manner by a seal member 90 attached to the terminal fitting 40.

As described above, according to the present embodiment, the metal nut 30 is held by the synthetic resin holding member 80, and the positioning hole 82 of the holding member 80 is fitted to the fitting protrusion 75 of the lower mold 71. By doing so, the functional part 20 (first cylinder part 21) in a form of covering the nut 30 and the boundary part between the nut 30 and the holding member 80 is formed by filling the mold with the molten resin. I am doing so.
By using the holding member 80 made of synthetic resin, the metal nut 30 can be positioned with respect to the mold without directly contacting the mold. Therefore, after the insert molding, the entire nut 30 is embedded in the functional portion 20 (first cylinder portion 21) made of synthetic resin, and the boundary portion between the nut 30 and the synthetic resin holding member 80 is also the functional portion 20. Since the metal nut 30 is not exposed to the outer surface of the synthetic resin functional portion 20, the boundary portion between the metal member (nut 30) and the resin member (functional portion 20) is embedded in the inside. Is not exposed to the outside. Therefore, according to this embodiment, the process for sealing the boundary part of a metal member and a resin member is unnecessary.

  Further, on the contact surface between the holding member 80 and the first cylinder part 21 (functional part 20), the back (first) from the exposed position of the positioning projection 81 of the holding member 80 on the lower end surface (outer surface) of the first cylinder part 21 is provided. A non-smooth portion 83 is formed in a form in which unevenness is arranged toward the inside of the cylindrical portion 21). Thus, even if liquid enters the gap between the positioning projection 81 on the lower end surface of the first cylindrical portion 21 and the liquid intrusion path is detoured and extended by the non-smooth portion 83. Therefore, it is possible to suppress the intrusion of liquid.

<Embodiment 2>
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the first cylindrical portion 21A and the holding member 90 are configured differently from the first embodiment. Since other configurations are the same as those of the first embodiment, the same configurations are denoted by the same reference numerals, and descriptions of structures, operations, and effects are omitted.
The holding member 90 is made of a synthetic resin, and has a bottomed cylindrical shape that is in close contact with a region excluding only an upper end portion of the outer peripheral surface of the nut 30 and a bottom surface (lower end surface) of the nut 30. On the outer peripheral surface of the holding member 90, a plurality of protrusions 91a, 91b, 91c extending in the circumferential direction and continuous over the entire periphery are formed at intervals in the vertical direction, and these protrusions 91a, 91b, 91c are formed. Thus, on the outer peripheral surface of the holding member 90, there is a non-smooth portion 92 having a configuration in which irregularities are continuously arranged upward from the lower end side of the holding member 90 (the side exposed at the lower end surface of the first cylindrical portion 21A). Is formed. In the present embodiment, three ridges 91a, 91b, 91c are formed, the two ridges 91a, 91b located at the upper and center are triangular sections, and the lower ridge 91c is a square section. It has become. Further, on the upper end surface of the holding member 90 having an annular shape, a triangular strip 91 d is formed concentrically with the holding member 90 and continuously around the entire circumference.

  The functional portion 20A is covered with a region in which the periphery of the nut 30 is exposed so that the opening at the upper end is exposed, and only the lower end portion of the outer peripheral surface of the holding member 90 is removed (region including the non-smooth portion 92). A first cylinder portion 21 </ b> A to cover is provided for each nut 30. The first cylinder portion 21 </ b> A also covers the boundary portion between the inner peripheral surface of the holding member 90 and the outer peripheral surface of the nut 30 at the upper end portion of the holding member 90. Further, the lower end surface of the first cylindrical portion 21A is exposed in a form in which the lower end portion of the holding member 90 protrudes downward.

  In addition, the mold for insert molding includes an upper mold 70, a lower mold 71A, and a slide mold 72, as in the first embodiment. A circular fitting recess 75A for fitting the lower end portion of the holding member 9080 is formed on the bottom surface of the molding hole 74A of the lower die 71A so as to open upward.

In order to insert-mold the functional portion 20A using the above-described mold, first, as shown in FIG. 10, the nut 30 is fitted into the holding member 90 without backlash. Hold. Next, the holding member 90 holding the nut 30 is set in the lower mold 71A, and the lower end portion of the holding member 90 is fitted to the fitting recess 75A without backlash. As a result, the holding member 90 and the nut 30 are positioned at predetermined positions in the lower mold 71A. At this time, the metal nut 30 does not come into direct contact with the lower mold 71A.
Thereafter, the slide mold 72 is moved to the molding position and the upper mold 70 is lowered to close the mold. From this state, the molten resin is injected and filled into the mold, and the synthetic resin is cooled and solidified. Just open it.

<Other embodiments>
The present invention is not limited to the embodiment described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention, and further, within the scope not departing from the gist of the invention other than the following. Various modifications can be made.
(1) In the above embodiment, the fastening nut for connecting the terminal fitting and the bus bar is used as the insert member. However, in the present invention, it is not an insert member having such functionality but a simple nut. Etc. may be used as insert members.
(2) Although the example applied to the electronic control unit has been described in the above embodiment, the present invention can also be applied to insert molded products other than the electronic control unit.

Plan view of Embodiment 1 Front view of functional part Sectional view showing the state where the nut is held by the holding member Sectional view showing the nut and holding member set in the mold Cross section showing insert molding process Functional section Sectional view showing the terminal bracket assembled to the functional part Partial cutaway front view of the functional part Sectional drawing of the function part of Embodiment 2. Sectional view showing the state where the nut is held by the holding member Sectional view showing the nut and holding member set in the mold

Explanation of symbols

20 ... functional part (resin molding member)
30 ... Nut (insert member)
71 ... Lower mold (mold)
80 ... Holding member 83 ... Non-smooth surface 20A ... Functional part (resin molding member)
71A ... Lower mold (mold)
90 ... holding member 92 ... non-smooth surface

Claims (3)

A metal insert member;
A holding member made of synthetic resin capable of holding the insert member and capable of fitting in a positioning state with respect to the mold; and
A resin molded member formed by filling a molten resin in a state where the holding member holding the insert member is fitted and positioned in the mold;
An insert-molded product, wherein the resin-molded member is configured to cover the insert member and a boundary portion between the insert member and the holding member. The contact surface between the holding member and the resin molded member is formed with a non-smooth portion having a configuration in which irregularities are arranged from the exposed position of the holding member to the back on the outer surface of the resin molded member. The insert molded product according to claim 1. Hold the metal insert member on the synthetic resin holding member,
It is in a positioning state by fitting the holding member to a mold,
A method of manufacturing an insert-molded product, comprising: molding a resin-molded member in a form of covering the insert member and a boundary portion between the insert member and the holding member by filling the mold with a molten resin. .

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