| 摘要 |
PURPOSE:To prevent generation of engine stall even at driving a prime mover at low rotating speed to effectively utilize output of the prime mover by instituting the inclined rolling angle of a variable capacity hydraulic pump on negative side at the pump pressure over a first instituted value. CONSTITUTION:When a hydraulic actuator 9 is driven with an operation lever for front 41 through a changeover valve 10, pump pressure in pipings 5 rises, an inclined rolling control device 22 is changed over by pressure in a pilot line 13 at the pump pressure over a first instituted value, the inclined rolling angle of a variable capacity hydraulic pump 21 is instituted on negative side, and the discharge oil of a fixed hydraulic pump 2 is returned to a tank with the variable capacity hydraulic pump 21. Hereby, the variable capacity hydraulic pump 21 functions as a motor, total input power of the pump is reduced, and engine stall of a prime mover is prevented. Thus, the output of the prime mover is effectively utilized. |
