Patent ID: 7089663

Claim:
A forming method of a throttle apparatus for an internal combustion engine, the throttle apparatus including a substantially tubular throttle body and a substantially disc-shaped throttle valve, the throttle valve having an axis around which the throttle valve rotate in the tubular throttle body between a close position and an open position, the throttle valve and the throttle body being molded substantially simultaneously in same molding dies in such a manner that the throttle valve is rotated by a predetermined angle with respect to a full closed position in which the throttle valve and the throttle body define a minimum gap therebetween, the forming method of the throttle apparatus, comprising: clamping a pair of molding dies to form a body cavity and a valve cavity therein, the body cavity being for molding a throttle body and the valve cavity being for molding a throttle valve in such a manner that the throttle valve is rotated by a predetermined angle with respect to a full closed position, so that the throttle valve is not in contact with an inner bore surface of the throttle body; substantially simultaneously injecting a melted material into the body cavity and the valve cavity; moving one of said dies away from the other of said dies; and protruding an ejector into the cavities in order to eject a solidified molding, wherein a gas evaporated from the melted material in the body cavity and the valve cavity is expelled from the body cavity and the valve cavity through a gas purge passage which is formed in the molding dies remote from a parting plane where said moving and fixed dies engage.