| 摘要 |
<p>A power steering apparatus includes an electric motor which drives a power steering pump. A vehicle speed detector senses the speed of the vehicle. A steering wheel rotation detector senses whether or not the steering wheel is being rotated. At low vehicle speeds, a control assembly effects operation of the electric motor to drive the power steering pump at a relatively low standby angular velocity prior to intitiation of a steering operation. Upon initiation and during of the steering operation at low vehicle speeds, the control assembly effects operation of the electric motor to drive the power steering pump at an angular velocity which varies as a function of vehicle speed. When the vehicle is traveling at a relatively high speed, the control assembly causes. the electric motor to drive the pump at an angular velocity which is less than the standby angular velocity, that is, at a very low speed or at a standstill. In one embodiment of the invention, rotation of the steering wheel is detected by sensing variations in the output from the power steering pump. In another embodiment of the invention, rotation of the steering wheel is detected by sensing variations in the current conducted to the electric motor which drives the power steering pump.</p> |
