Patent ID: 6718919
Filing Date: 2004-04-13
Classification: F01L

Abstract:
A valve driving apparatus for driving a valve element controlling intake gas flow or exhaust gas flow of an internal combustion engine, comprising:a valve driving portion including a magnetic path which comprises: a magnetic flux generating element comprising an electromagnetic coil wound so as to generate a magnetic flux; and a magnetic field generating element comprising three pole members to distribute the magnetic flux and form at least one magnetic field; a magnetized member that is movable within said magnetic field in cooperation with a valve rod that is integral with a valve element, said magnetized member having two magnetized surfaces with different polarities; and a current supply for supplying a driving current to said electromagnetic coil so as to correspond to a valve opening direction and a valve closing direction; wherein said three pole members are aligned in a lengthwise direction of said valve rod; wherein said electromagnetic coil is wound about an axis perpendicular to the lengthwise direction; and wherein a gap between one of said three pole members and said magnetized member is different in size from a gap between at least one other of said three pole members and said magnetized member.