Toyota Jidosha Kabushiki Kaisha

Mituyoshi Sato

Minoru Uozumi

Masao Nakayama

Kunio Shimizu

A vacuum casting apparatus secures gas tightness of the die cavity without welding together a straight-tubular stalk and a flange or flanges, thus permitting an excellent quality casting. A flange is mounted on an outer periphery of a stalk, and secured between a gas-tight chamber and a die, forming a recess bounded by the die, a surface of the flange, and an outer surface of the stalk. The space inside the chamber is evacuated to a first degree of vacuum so that molten metal is withdrawn into the stalk and overflows the end of the stalk, and flows into the recess. Molten metal in the recess cools and solidifies to form a gas-tight seal between the stalk and the flange. Then, the space inside the chamber is evacuated to a second degree of vacuum and molten metal is withdrawn through the stalk and into the cavity of the die.

Vacuum casting apparatus and method using flange-free stalk

A vacuum casting apparatus secures gas tightness of the die cavity without welding together a straight-tubular stalk and a flange or flanges, thus permitting an excellent quality casting. Two flanges are mounted in a mutually spaced-apart relation on an outer periphery of a stalk, and secured between a gas-tight chamber and a die. The gas-tight chamber is fitted on the die from above to form a gas-tight space between the two flanges. The space is evacuated to a pressure close to an inner pressure formed in a cavity of the die during vacuum casting. Thus, air that intrudes into the cavity of the die through small gaps between the flanges and the stalk is reduced, thereby preventing casting defects which might otherwise result. An end of the stalk inserted into the die is also spread to bring an outer periphery of the stalk into close contact with an inner periphery of a flange mounted on the stalk. A first degree of vacuum is applied to the gas-tight chamber to draw molten metal through the stalk to a level above the insertion end of the stalk, and below an inlet of the die cavity, so that the molten metal cools and forms a gas-tight seal about the insertion end of the stalk, before a second degree of vacuum is applied to withdraw molten metal into the die cavity.

Vacuum casting apparatus using flange-free stalk

A suction casting apparatus is disclosed, which comprises a ventilating casting die, a chamber box and a surface peat for supporting the casting die and chamber box. The surface plate has a a through hole for passing a stalk therethrough, and its surface is formed with grooves which extend from the through hole to an area outside a die mounting area and inside a chamber box mounting area. External air entering through a sealed clearance between the surface plate and the stalk and combustion gas generated from the casting die are quickly led through the grooves into the chamber inner space to be quickly exhausted to the outside.

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Toyota, Japan

Mituyoshi Sato