To improve operability by a method wherein the dead zone of an electric motor and the dead zone of a clutch are formed, the dead zone of the electric motor is set to a value higher than the bead zone of the clutch, and the generation of a shock during engagement and disengagement of the clutch of a motor-operated power steering device is suppressed through simple constitution.
The electric motor control part 10 of a motor-driven power steering device comprises a characteristic memory part 31; a command processing part 32; and an electric motor drive part 33. The characteristic memory part 31 incorporates the drive characteristics of an electric motor 6 for steering torque. The command processing part 32 computes a drive command responding to a signal from a torque detecting means 30 from the driven characteristics. The electric motor drive part 33 drives an electric motor 6 by means of a command from the command processing part 32. Drive characteristics incorporated in the characteristic memory part 31 are set in such a manner that, during a time containing a time when steering torque is not exerted, a range wherein steering torque is below low specified torque is set as a dead zone. The dead zone is set to a value higher than limit torque in the dead zone of a clutch, and a clutch is engaged and disengaged in a range wherein the electric motor is not run.
YONEDA ATSUHIKO
NAKAMURA YOSHITO
