Forming method of throttle apparatus for internal combustion engine

摘要

A throttle valve and the throttle body are formed substantially simultaneously in the same dies. The melted resin is injected in to a cavity through a pair of valve gates. The gas evaporated from a melted resin and remaining air in the cavity are expelled from the cavity into the atmosphere through a gas purge passage. A first and a second split lines of a first and second insert dies function as the gas purge passage. A shortshot and a corrosion generated by the gas can be avoided.