| 摘要 |
PURPOSE:To control operation of a steering shaft without enlarging the rating of a solenoid by installing two pilot pressure generators, exciting each of their solenoids and generating each pressure (pilot pressure) in a fixed throttle, through which selecting a spool valve. CONSTITUTION:A rear-wheel steering system is provided with a steering shaft 80 being shifted by hydraulic pressure being added to either of cylinder chambers 94, 95 and steering rear wheels, and pressure oil to be fed to these cylinder chamber 94, 95 is selected by a spool valve mechanism inclusive of a spool 60. In this case, there are provided a first pilot pressure generator comprising a first solenoid 20 driving a first rod member 23 in the axial direction, and a second pilot pressure generator comprising a second solenoid 30 driving a second rod member 23 in the axial direction, respectively. One side of these solenoids 20, 30 is excited, driving these rod members 23, 33, and two fixed throttles 42, 52 is made to generate pressure, thereby adding pilot pressure to both third and fourth cylinder chambers 72, 82, thus the spool 60 is selected. |
