| 摘要 |
PURPOSE:To secure an ideal power-assist characteristic at all times, by installing a by-pass valve by-passing both chambers of a cylinder for a power actuator, while controlling this valve according to car speed. CONSTITUTION:A control valve 3 is rotated by rotation of a steering wheel 1 via a column shaft 2, and when the discharged oil of a hydraulic pump driven by a motor 7 is fed to either chamber of a power actuator 6 from an output port A or B, a piston of the actuator 6 is shifted to some extent whereby the sense of the steering wheel is altered by dint of power. In this case, a by-pass valve 5 interconnected through both chambers of the actuator 6 is installed in a space between the control valve 3 and the actuator 6. And, with a controller 8 employed, when the car speed detected by a car speed sensor 11 reaches the specified value, the by-pass valve 5 is opened and in case the car speed exceeds the specified value, the valve 5 is controlled so as to be closed by degrees in proportion to an increase in the car speed. |
