Patent ID: 8813820

Claim:
A gravity casting mold, comprising: a first mold including: a first part of a turbine housing cavity formed in a lower part of the first mold and having a twin scroll part; a first part of a first riser formed at a location above the twin scroll part; first parts of a sprue and of a runner formed in a first side of the twin scroll part so as to feed molten metal into the twin scroll part; and a first part of a second riser formed in a second side of the twin scroll part; a second mold assembled with the first mold, the second mold including: a second part of the turbine housing cavity formed in a lower part of the second mold and engaged with the first part of the turbine housing cavity of the first mold so as to form the turbine housing cavity; a first part of an exhaust manifold cavity formed in an upper part of the second mold and connected to the second part of the turbine housing cavity; and a first part of a third riser formed at a location above the first part of the exhaust manifold cavity; and an exhaust runner mold placed in an upper part between the first mold and the second mold, wherein a first surface of the exhaust runner mold includes: a second part of the exhaust manifold cavity engaged with the first part of the exhaust manifold cavity of the second mold so as to form the exhaust manifold cavity; and a second part of the third riser formed at a location above the second part of the exhaust manifold cavity and engaged with the first part of the third riser so as to form the third riser, and a second surface of the exhaust runner includes: a second part of the first riser engaged with the first part of the first riser of the first mold so as to form the first riser; second parts of the sprue and of the runner engaged with the first parts of the sprue and of the runner of the first mold so as to form the sprue and the runner; and a second part of the second riser engaged with the first part of the second riser of the first mold so as to form the second riser, wherein a heating sleeve is provided in the first riser so as to prevent shrinkage of the molten metal in the twin scroll part, wherein the heating sleeve is closed in an upper end, with a gas ejection hole formed through the upper end of the heating sleeve.