| 摘要 |
PURPOSE:To permit the correct and speedy mode change by carrying out control so that the steering speed of a steering wheel is decelerated in the vicinity of the straight advance direction when mode is changed, in the constitution in which steering mode can be changed when the steering wheel is directed in the straight advance direction. CONSTITUTION:A potentiometer for detecting the steering angle for the front and rear wheels is connected with a control part 54 through an A/D converter 53. A mode selecting switch 46 is connected with the control part 54, and the front wheel steering mode, rear wheel steering mode, and the front/rear wheel reverse phase steering mode can be selected freely. Solenoids 26 and 29 for changing mode by selecting the oil passage of a solenoid valve and a solenoid 34 for selecting a flow rate control valve for controlling the working oil are installed on the output side of the control part 54. When mode is selected, the control part 54 judges if the angle of a steering wheel is in the vicinity of a neutral point or not, and selects the solenoid 34, and the turning operation speed of the steering wheel is decelerated by reducing the flow rate itself of a whole hydraulic steering mechanism, and mode selection is carried out correctly at the neutral point position. |
