Pressure casting device and method for manufacturing castings using the same

Abstract

A pressure casting device includes: a chamber with an opening portion formed on one side and sealed on the other side; an outer mold having a filling space into which a molten metal is filled, and a casting space connected to the filling space such that the molten metal is supplied from the filling space into the casting space and filled in a shape of a casting; and a self-shielding mold table configured to fix the outer mold and including first and second sealing portions to seal the opening portion of the chamber and an inner side portion facing the opening portion, respectively, and an outer mold support portion contacting the outer mold to support the outer mold; a pneumatic pressure injector provided at one side portion of the chamber to supply pneumatic pressure into the chamber; and a tilting device to rotate the chamber.

What is claimed is: 
     
         1 . A pressure casting device comprising:
 a chamber having an opening portion formed on a first side, the chamber sealed on a second side;   an outer mold including:
 a filling space into which a molten metal is filled, and 
 a casting space connected to the filling space such that the molten metal is supplied from the filling space into the casting space and filled in a shape of a casting; 
   a self-shielding mold table configured to fix the outer mold, wherein the self-shielding mold table is insertable into and drawable from the chamber includes:
 first and second sealing portions configured to seal the opening portion of the chamber and an inner side portion facing the opening portion of the chamber, respectively, and 
 an outer mold support portion contacting the outer mold to support the outer mold; 
   a pneumatic pressure injector provided at one side portion of the chamber to supply pneumatic pressure into the chamber; and   a tilting device configured to rotate the chamber.   
     
     
         2 . The pressure casting device of  claim 1 , wherein
 the outer mold is made of a porous material and manufactured from a sand mold or a powder-sintered metal mold.   
     
     
         3 . The pressure casting device of  claim 1 , wherein
 a core structure for forming a hollow in the casting is provided in the casting space.   
     
     
         4 . The pressure casting device of  claim 1 , wherein
 an edge end of each of the first and second sealing portions is in contact with an inner surface of the chamber and is sealed by a sealing member.   
     
     
         5 . The pressure casting device of  claim 4 , wherein
 the first and second sealing portions have different areas and are configured to cause a pressing force to act from the opening portion to the inner side portion.   
     
     
         6 . The pressure casting device of  claim 1 , wherein
 the pneumatic pressure injector is configured to inject compressed air or nitrogen into the chamber at a pressure in a range of 1 kg/cm2 to 100 kg/cm2.   
     
     
         7 . The pressure casting device of  claim 6 , wherein
 when the pneumatic pressure injector injects the compressed air or nitrogen into the chamber,   a first pressure is applied to the second sealing portion, wherein the first pressure is higher than a second pressure applied to the first sealing portion, so that the self-shielding mold table is fixed to avoid detachment from the chamber.   
     
     
         8 . The pressure casting device of  claim 1 , wherein
 the tilting device is configured to rotate the chamber at an angle in a range of 90° to 180°.   
     
     
         9 . The pressure casting device of  claim 8 , wherein
 the molten metal filled in the filling space flows into the casting space when the tilting device rotates.   
     
     
         10 . The pressure casting device of  claim 1 , further comprising:
 a pressure reducer configured to reduce and exhaust the pressure in the chamber after the molten metal in the casting space is completely solidified.   
     
     
         11 . A method for manufacturing a casting using a pressure casting device, the method comprising
 injecting a molten metal into a filling space of an outer mold of the pressure casting device;   inserting the outer mold into a chamber of the pressure casting device and sealing the chamber, and applying pneumatic pressure into the chamber to pressurize the chamber;   rotating the chamber, by a tilting device, to inject the molten metal filled in the filling space into a casting space of the outer mold;   solidifying the molten metal while maintaining a pressurized state in the chamber to form a casting; and   reducing and exhausting the pressure in the chamber after formation of the casting is completed, drawing the outer mold from the chamber, and then demolding the casting.   
     
     
         12 . The method of  claim 11 , wherein
 in injecting the molten metal into the filling space of the outer mold,   the molten metal is injected into the filling space using a molten metal injector in a state where the outer mold is drawn from the chamber.   
     
     
         13 . The method of  claim 11 , wherein
 in demolding the casting,   the outer mold is separated and the casting is demolded in a state where the outer mold is drawn from the chamber.   
     
     
         14 . A pressure casting device comprising:
 a chamber including a bottom portion and a cover portion sealed by being combined with the bottom portion;   an outer mold provided inside of the chamber and including:
 a filling space into which a molten metal is filled, and 
 a casting space connected to the filling space such that the molten metal is supplied from the filling space into the casting space and filled in a shape of a casting; and 
   a pneumatic pressure injector provided at one side portion of the chamber to supply pneumatic pressure into the chamber.   
     
     
         15 . The pressure casting device of  claim 14 , wherein
 the outer mold includes:   a metal mold supported by the bottom portion and forming a part of the casting space; and   a sand mold combined with an upper portion of the metal mold and forming another part of the casting space and the filling space.   
     
     
         16 . The pressure casting device of  claim 14 , wherein
 the molten metal is supplied from the filling space into the casting space by gravity.   
     
     
         17 . The pressure casting device of  claim 14 , wherein
 a sand mold of the outer mold is made of a porous material.   
     
     
         18 . The pressure casting device of  claim 14 , wherein
 a core structure configured to form a hollow in the casting is provided in the casting space.   
     
     
         19 . The pressure casting device of  claim 14 , wherein
 an edge end of the cover portion is in contact with an upper surface of the bottom portion and is sealed by a sealing member.   
     
     
         20 . The pressure casting device of  claim 14 , wherein
 the pneumatic pressure injector is configured to inject compressed air or nitrogen into the chamber at a pressure in a range of 1 kg/cm2 to 100 kg/cm2.