| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power steering device capable of preventing certainly an electric motor from overheating without bringing about large-size construction of the device and without using a temperature sensor. SOLUTION: The electric power steering device is to set the target amperage of the motor 22 to generate the steering assist force on the basis of the steering torque input from a steering wheel and control the current feed to the motor 22 so that the motor current becomes the target amperage, wherein the effective value of the motor current is determined by sampling the motor current in a large number at the prescribed intervalsΔt (by an amperage effective value calculation part 45), and when the effective value exceeds the set value, amperage corrective value is determined for correcting the target current so that it becomes smaller with larger effective value (by an amperage corrective value calculation part 46), and the target current is corrected based on this amperage corrective value. As a result, the motor 22 can be prevented from overheating without fitting the motor 22 with radiating fins, a cooling device, temperature sensor, etc. COPYRIGHT: (C)2007,JPO&INPIT |
