Mold apparatus for high pressure casting

Abstract

A mold apparatus for high pressure casting includes an upper mold having an internal space filled with a molten metal and a core pin elevating groove at an inner wall of the upper mold. A lower mold is disposed at a lower part of the upper mold and fixed with an insert. A core pin portion is elevatably installed in the core pin elevating groove to be elevated depending on a filling pressure of the molten metal filled in the internal space.

What is claimed is: 
     
         1 . A mold apparatus for high pressure casting, comprising:
 an upper mold having an internal space filled with a molten metal and a core pin elevating groove at an inner wall of the upper mold;   a lower mold disposed at a lower side of the upper mold and fixed with an insert; and   a core pin portion elevatably disposed in the core pin elevating groove to be elevated depending on a filling pressure of the molten metal filled in the internal space.   
     
     
         2 . The mold apparatus for high pressure casting of  claim 1 , wherein the core pin portion includes:
 a fixed bar having one side inserted into and fixed to the core pin elevating groove;   a core pin disposed at another side of the fixed bar to be elevated along an inner circumferential surface of the core pin elevating groove; and   a spring having one side fixed to the core pin and another side fixed to an inner circumferential surface of a ceiling of the core pin elevating groove to provide an elastic force to the core pin.   
     
     
         3 . The mold apparatus for high pressure casting of  claim 2 , wherein the spring satisfies a spring constant value calculated by the following Equation:
   spring constant=casting pressure×core pin area/core pin moving distance.
   
     
     
         4 . The mold apparatus for high pressure casting of  claim 3 , wherein the spring is made of any one of a spring steel, an oil-tempered wire for a valve spring, a hard drawn steel wire, a piano wire, and a stainless steel wire that have a lateral modulus of 7000 to 8000 kgf/mm 2 . 
     
     
         5 . The mold apparatus for high pressure casting of  claim 1 , wherein the molten metal filled in the internal space is filled at a pressure of 10 to 1000 kg/cm 2 . 
     
     
         6 . The mold apparatus high pressure casting of  claim 1 , wherein the core pin portion selectively supports the insert.