Method of manufacturing casting for mold for molding tire

Abstract

Provided is a method of manufacturing a casting for a mold for molding a tire, wherein twist and warp deformation of each block of the casting is less likely to occur when the casting shrinks, the difference between the degrees of shrinkage of cope and drag is small, the casting, even if large-sized, can be produced in a relatively short molten metal solidifying time, and healthy castings can be easily obtained. A method of manufacturing a casting for a mold for molding a tire of a sectional mold type in which the mold is opened and closed by dividing the mold into a plurality of pieces in the circumferential direction comprises a process of manufacturing each of divided block castings ( 1 ) by casting them individually. In this process, molten metal is poured into a casting mold where chills are disposed on four sides, the sides being an upper surface portion ( 2 a ), a lower surface portion ( 2 b ) and both sides of circumferentially divided surfaces ( 3 a, 3 b ), and surrounding from four directions a design surface ( 6 ) which is a contact surface with the mold from four directions, such that at least the chills surround the design surface ( 6 ) continuously.

1 . A method of manufacturing a casting for a mold for molding a tire of a sectional mold type in which the mold is opened and closed by dividing the mold into a plurality of pieces in the circumferential direction, said method comprising
 a process of manufacturing each of divided block castings by casting them individually, in which process, molten metal is poured into a casting mold where chills are disposed on four sides, the sides being an upper surface portion, a lower surface portion and both sides of circumferentially divided surfaces, and surrounding from four directions a design surface which is a contact surface with the mold from four directions, such that at least the chills surround said design surface continuously.   
     
     
         2 . The method of manufacturing a casting for a mold for molding a tire according to  claim 1 , wherein opposing said chills are respectively disposed symmetrically on said four sides, the sides being an upper surface portion, a lower surface portion and both sides of circumferentially divided surfaces. 
     
     
         3 . The method of manufacturing a casting for a mold for molding a tire according to  claim 1 , wherein a pair of tap holes for said casting mold are disposed symmetrically on said upper surface portion and lower surface portion. 
     
     
         4 . The method of manufacturing a casting for a mold for molding a tire according to  claim 1 , wherein a pair of tap holes for said casting mold are disposed symmetrically on said both sides of circumferentially divided surfaces. 
     
     
         5 . The method of manufacturing a casting for a mold for molding a tire according to  claim 1 , wherein a tap hole and/or a runner which provides the tap hole with molten metal are/is formed inside said chill.