| 摘要 |
PURPOSE:To hold the steering angle of rear wheels by constituting the oil pressure circuits from a power steering valve to both power cylinders of front and rear so as to make ON/OFF right and left independently, and preventing the rear power cylinder from returning to the neutral position due to pressure drop. CONSTITUTION:An oil passage changeover valve 10 is connected to both power cylinders 3, 30 of front and rear in series so as to steer the rear wheels in antiphase at steering a large steering angle. In this case, the oil passage changeover valve 10 is constituted of a cylinder 11 and a spool 12 moving according to a handle angle. The cylinder 11 is formed with a power steering valve 2, respective ports 11a-11f connected to both power cylinders 3, 30, and respective oil passages 11g, 11h through which a part of oil pressure is applied on the end faces of the spool 12. Meanwhile, the spool 12 is formed with respective oil passages 12a-12e so as to connect the front power cylinder 3 to the power steering valve 2 at a small steering angle, and connect together both power cylinders 3, 30 in series at a large steering angle. |
