| 摘要 |
PURPOSE:To keep a steering force constant irrespective of the magnitude of a load by detecting a load applied to a steering wheel, reading the optimum flow rate of a control valve suited to said detected load and controlling a flow rate controlling means provided on the upper course side of said control valve. CONSTITUTION:The power steering device of a fork lift controls its rear wheel 7 as a steering wheel by feeding a working fluid from a hydraulic pump 10 to a power cylinder 9 via a flow divider 12 and a control valve 14. In this case, a pressure sensor 23 for detecting the pressure of a tilt cylinder 22 which is varied in accordance with a variable load is provided. Also, a variable flow rate regulating valve 19 for controlling the feeding flow rate of the working fluid to the control valve 14 is provided. And, by reading the optimum flow rate of the control valve corresponding to the detected variable load from a memory device 28 by a CPU 29, its control signal is outputted to a stepping motor 20 to control the opening of the variable flow rate regulating valve 19. |
