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AssigneeMitsubishi Denki Kabushiki Kaisha
InventorsShunichi Wada, Tadayuki Hara, Yasuo Naito, Shinichi Kohge, Kazuhisa Nishino
Estimating the term…
A motor-driven power steering apparatus and method for a vehicle are able to avoid frequent on-off operations of an electromagnetic clutch 14 as much as possible, which connects or disconnects a motor 13 with or from a steering system, thus improving the durability of the clutch 14 and suppressing the generation of undesirable noise and shocks upon connection and disconnection of the clutch 14. A clutch controller 191 controls a clutch current Ic supplied to the clutch 14 based on the vehicle speed V in such a manner that it sets the clutch current Ic to a first predetermined clutch current level I(V) so as to place the clutch into a substantially engaged state when the vehicle speed V is less than a first predetermined vehicle speed Vo, and to a second predetermined clutch current level Icr which is less than the first predetermined clutch current level I(V) so as to place the clutch into a partially engaged state when the vehicle speed V is equal to or greater than the first predetermined vehicle speed Vo. Preferably, the clutch current Ic is set to a third predetermined clutch current level Ico which is less than the second predetermined clutch current level Icr so as to substantially disengage said electromagnetic clutch when a steering torque T is equal to or greater than a predetermined value To when the vehicle speed is equal to or greater than the first predetermined value Vo.
A motor-driven power steering apparatus for a vehicle comprising:
A method of controlling a motor-driven power steering apparatus for a vehicle in which a motor is coupled via an electromagnetic clutch to a steering system having a steering wheel for generating an assisting torque to assist a steering motion of said steering system induced by a driver of the vehicle, and in which a motor current supplied to said motor is controlled on the basis of a vehicle speed at which the vehicle is -travelling, and a steering torque applied to said steering wheel by the driver, said method comprising the steps of;
Dependencies are inferred from the claim text.