Method of manufacturing cup structure

A forging press apparatus for manufacturing a cup structure, the forging press apparatus comprising:

• a die including a die hole into which a material is to be provided, the material serving as a starting material of the cup structure with a bottomed cylindrical shape, the die hole having a depth that is able to accommodate an entirety of the cup structure, and a relief hole smaller in diameter than the die hole and extending downward from the die hole;
• a molding punch movable between an inside and an outside of the die hole along a first direction connecting the inside and the outside, and configured to press an inner portion inside a peripheral portion of the material contained in the die hole;
• a pressing member movable along the first direction between the inside and the outside of the die hole, and provided around an outer periphery of the molding punch to press the peripheral portion of the material;
• a pressure receiving plate that is provided on the molding punch and that restricts an upward movement of the molding punch;
• and
• an upper knock-out pin that is located above the pressing member and that penetrates the pressure receiving plate;
• wherein
• in a forging process of forging the material, the molding punch is configured to move inward along the first direction to apply a force to plastically deform the inner portion of the material to cause the peripheral portion of the material to be brought into contact with the pressing member, and a portion of the material to be pushed out into the relief hole by the molding punch to form a projection while a space is secured below the projection;
• in the forging process of forging the material, the pressing member is configured to be movable outward along the first direction, by receiving an outward force from the peripheral portion of the material caused in response to the pressing of the inner portion by the molding punch
• in the forging process of forging the material, the upper knock-out pin is configured to be moved upward by the pressing member while the upper knock-out pin penetrates the pressure receiving plate;
• and
• after the forging process of forging the material, the upper knock-out pin is configured to be moved downward to move the pressing member downward relative to the molding punch.