Injection molding die and manufacturing method of insert molded article

Patent metadata

Field	Value
Publication number	US-2016346975-A1
Application number	US-201615154056-A
Country	US
Kind code	A1
Filing date	May 13, 2016
Priority date	May 27, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

The present invention is intended to provide an injection molding die that improves the strength of adhesion between an insert and a plastic in an insert molded article while suppressing fluctuations in the strength of adhesion.
An injection molding die is used to manufacture an insert molded article by placing an insert 12 with a thermoset resin adhesive in the molding die and injecting a molten plastic material P from a gate G into a cavity C. The gate G is arranged at a position separated by 0.2 mm or more in an out-of-plane direction from a surface A 1 of the adhesive applied to the joining surface of the insert 12 . During injection molding, the wall surface shear stress generated on the adhesive applied to the joining surface of the insert 12 relative to the plastic near the gate G becomes small. The adhesive is not swept away by the high-pressure molten plastic material P without having to bring the adhesive applied to the joining surface A of the insert 12 into the semi-cured state. Accordingly, it is possible to conduct injection molding without bringing the adhesive into the semi-cured state.

First claim

1 : An injection molding die for use in injection molding in which an insert with a thermoset resin adhesive applied to a joining surface relative to a plastic is placed in the molding die and a molten material for the plastic is injected from a gate into a cavity of the molding die to manufacture an insert molded article, wherein the gate is arranged at a position separated by 0.2 mm or more in an out-of-plane direction from the surface of the adhesive applied to the joining surface of the insert.

2 : The injection molding die according to claim 1 , wherein the insert has an annular shape, the gate is an inner disc gate, and the molding die has an insert core-type molding die structure or a slide core-type molding die structure.

3 : A manufacturing method of an insert molded article using the injection molding die according to claim 1 , comprising:
an adhesive application step of applying the adhesive to a surface of the insert including the joining surface; a natural drying step of volatilizing a solvent contained in the adhesive by natural drying or a drying and solidification step of volatilizing the solvent contained in the adhesive to dry and solidify the adhesive under temperature conditions lower than the temperature at which the adhesive starts cross-linking reaction; and an injection molding step of placing the insert having undergone the natural drying step or the drying and solidification step in the molding die and injecting the molten material for the plastic from the gate into the cavity of the molding die.

4 : The manufacturing method of an insert molded article according to claim 3 , wherein the insert molded article is a magnetic encoder for use in a bearing device for automobile wheel support, the insert is an annular fixing member attachable to a rotating body, and the plastic is an annular plastic magnet.

5 : A manufacturing method of an insert molded article using the injection molding die according to claim 2 , comprising:
an adhesive application step of applying the adhesive to a surface of the insert including the joining surface; a natural drying step of volatilizing a solvent contained in the adhesive by natural drying or a drying and solidification step of volatilizing the solvent contained in the adhesive to dry and solidify the adhesive under temperature conditions lower than the temperature at which the adhesive starts cross-linking reaction; and an injection molding step of placing the insert having undergone the natural drying step or the drying and solidification step in the molding die and injecting the molten material for the plastic from the gate into the cavity of the molding die.

6 : The manufacturing method of an insert molded article according to claim 5 , wherein the insert molded article is a magnetic encoder for use in a bearing device for automobile wheel support, the insert is an annular fixing member attachable to a rotating body, and the plastic is an annular plastic magnet.

Assignees

• Nakanishi Metal Works Co

Inventors

• Kamiji Michiyuki
• Ito Yoshihiro
• Oka Nobumasa

Classifications

• B29C45/1459

  Coating annular articles · CPC title

• B29C2045/0027

  Gate or gate mark locations · CPC title

• B29C45/14311 Primary

  using means for bonding the coating to the articles (B29C45/14795 takes precedence) · CPC title

• B29K2995/0008

  Magnetic or paramagnetic · CPC title

• B29C45/0046

  Details relating to the filling pattern or flow paths or flow characteristics of moulding material in the mould cavity · CPC title