| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power steering device elongating a service life of a power supply relay without any additional component. SOLUTION: The electric power steering device comprises: a motor 18 for steering assist, driven by a drive circuit 13 to which output voltage of an on-vehicle battery Ba is applied through a contact 15a; a current detector 17 detecting a current passing through the motor 18; and a torque detector 10 detecting steering torque. The electric power steering device controls the current to be passed through the motor 18 based on the detected steering torque. The electric power steering device further comprises: an estimating means 20 estimating a temperature of the contact 15a based on the current detected by the current detector 17; a determining means 20 determining whether or not the estimated temperature exceeds a first temperature; a means 8 for increasing voltage applied to the drive circuit up to K (>1) times thereof, when the determining means 20 determines that the estimated temperature exceeds the first temperature; and a means 16 decreasing the current to be passed through the motor 18 to 1/K times. COPYRIGHT: (C)2009,JPO&INPIT |
