| 摘要 |
PURPOSE:To surely switch the steering mode to the desired one regardless of the drift of the steering angle between front and rear wheels by temporarily fixing the wheels of one side at the neutral position until the wheels of the other side are turned to the neutral position if the wheels of one side of the front and rear wheels are turned to the neutral position first when the steering mode is switched. CONSTITUTION:Direction switching valves 25, 26 are provided on the discharge path of a hydraulic pump 24 to control the feed/discharge of pressure oil to a front wheel steering cylinder 9 and a rear wheel steering cylinder 19, and the front wheel steering mode, rear wheel steering mode, same-phase four-wheel steering mode and opposite- phase four-wheel steering mode are established by the on or off of solenoids A, B, C of the direction switching valves 25, 26. When the steering mode is switched to the same-phase four-wheel steering mode or the opposite-phase four-wheel steering mode, the front wheel steering angle is detected. When either the front wheels or the rear wheels are turned to the neutral position, the steering angle of the rear wheels is detected, and the wheels of one side are temporarily fixed at the neutral position until the wheels of the other side are turned to the neutral position based on both detected values. |
