| 摘要 |
PURPOSE:To enable to perform the steering such as stationary steering and at very low speed running with a small operating force by a constitution wherein the pressure oil flowing from a control valve to an auxiliary power cylinder is changed over. CONSTITUTION:An auxiliary power cylinder 13 is connected on a rear wheel axle 19 side. A control valve 14 changes the flow rates of pressure oils, which are supplied from a hydraulic pump 11 to a main power cylinder 12 to the auxiliary power cylinder 13 in response to a steering force in such a manner as to supplement the steering force of the main power cylinder 12. A change-over valve 15 is provided across hydraulic pipings for turning left and right 79 and 80, both of which connect the control valve 14 and the auxiliary power cylinder 13 with each other, and is open and closed in response to the vehicular speed. Consequently, when a truck 86 is in a standstill, the auxiliary power cylinder 13 is interlocked with the main power cylinder 12. Except when the truck 86 is in a standstill, the pressure oils in cylinder chambers 91 and 92 are escaped to a reservoir 85 side. |
