Throttle apparatus for an internal combustion engine

摘要

A throttle device is provided for driving to open and close a throttle valve which controls an intake air flow rate of an internal combustion engine via an electric actuator. A motor casing receives a motor forming the electric actuator, and a gear casing receives gear mechanism transmitting a driving force of the motor to a valve shaft. Both casings are integrally formed within a throttle body. A motor insertion opening of the motor casing is opened to the gear casings. The motor is mounted by securing a motor bracket by tightening threaded fasteners into a plurality of threaded holes formed on the peripheral edges of the motor insertion opening. The motor bracket has a curved edge between one thread fastening position to another thread fastening position, and the gear casing is provided a curved portion adapting to said curved edge of the motor bracket.