| 摘要 |
<p>A motor-driven power steering apparatus comprising a steering assisting motor, a torque sensor detecting steering torque, a vehicle speed sensor, and a steering angular velocity detecting unit detecting steering angular velocity of steering mechanism. The power steering apparatus sets the value of current to be delivered to the steering assisting motor in correspondence with the detected steering torque and vehicle speed. The power steering apparatus sets the current value to be 0 when the steering torque remains in the dead zone in which the steering torque value is less than the first predetermined value. If the steering torque is more than the first predetermined value and less than the second predetermined value, the current value is set to increase as the steering torque value increases. If the steering torque is in excess of the second predetermined value, the growth rate of the current value against the steering torque is set to diminish as the vehicle speed rises. Further, the apparatus sets the subtraction current of which value increases as the detected steering angular velocity and the vehicle speed increase, and then subtracts the subtraction current from the set current value, transmitting the subtracted result to the motor. Since the value of the subtraction current grows when the vehicle runs fast and a small value of current is set, only a small amount of current flows through the motor.</p> |
