| 摘要 |
PURPOSE:To improve the control performance of body roll by reducing roll rigidity for a rear wheel side with the increase of a front and rear wheel steering angle ratio in the same phase direction, and setting the roll rigidity higher for a rear wheel side, upon detection of a transient turning state. CONSTITUTION:A hydraulic fluid is supplied to the hydraulic fluid chambers 2FR and 2FL of actuators 1FR and 1RL provided between right and left front wheels (rear wheel side not shown herein) and a body, through a high pressure passage 18 connected to the delivery side of a pump 6 via pressure control valves 32 and 34. Also, the fluid in each of the hydraulic fluid chambers 2FR and 2FL can be discharged to a tank via a low pressure passage 38. In this case, a control device not shown herein controls each of the pressure control valves 32 and 34, in such a way that roll rigidity for a rear wheel side is decreased with the increase of a front and rear wheel steering angle ratio in a four-wheel steering device wherein the aforesaid ratio is being changed in the same phase direction from a reverse phase direction, depending upon a speed increase, while the roll rigidity for the rear wheel side is increased upon detection of a transient turning state. |
