| 摘要 |
PROBLEM TO BE SOLVED: To provide a load pressure sensitive hydraulic pressure circuit which prevents vehicle speed from being reduced even when processed in pivot turn. SOLUTION: In the hydraulic pressure circuit, right/left unload valves 50 and 60 are arranged also in load pressure oil discharging oil paths 13a and 13b which branch from load pressure oil paths 11a and 11b and reach load pressure oil accommodating tanks T6 and T8. W when a differential pressure between a discharge pressure and a load pressure becomes a first reference pressure or less which is determined by energizing forces of setting springs 55 and 65 prepared in advance, the unload valves are switched to an intercepting position (c) intercepting the oil flows to discharging oil accommodating tanks T5 and T7 and to the load pressure oil accommodating tanks T6 and T8 while being energized by the setting springs 55 and 65. When the differential pressure is greater than or equal to the first reference pressure and is a second reference pressure or less, the unload valves are switched to a first communicating position (b) permitting the oil flows only to the discharging oil accommodating tanks T5 and T7. When the differential pressure exceeds the second reference pressure, the unload valves are switched to a second communicating position (a) permitting the oil flows to the discharging oil accommodating tanks T5 and T7 and load pressure oil accommodating tanks T6 and T8. COPYRIGHT: (C)2011,JPO&INPIT |
