Operating machine

摘要

There is provided a split-flow hydraulic pump-equipped operating machine. The travel independent valve is designed to be switched to the merging position in the case of driving the front working device without actuation of the travel device or in the case of driving the travel device and the front working device concurrently, and switched to the independently feeding position in the case of driving the travel device without actuation of the front working device. The load sensing system controls the discharge flow rate of the hydraulic pump on the basis of a pressure difference between the discharge pressure of the hydraulic pump and the maximum load pressure of the hydraulic actuator in any of the case of driving the travel device, the case of driving the front working device, and the case of driving both the travel device and the front working device.

主权项

1. An operating machine comprising:
right-side and left-side travel devices; a hydraulic actuator for driving the left-side travel device; a hydraulic actuator for driving the right-side travel device; a front working device; a hydraulic actuator for driving the front working device; a variable displacement hydraulic pump for discharging pressure oil to be fed to each of the hydraulic actuators, the variable displacement hydraulic pump being a split-flow-type and having a first discharge port P1 and a second discharge port P2 both for discharging the pressure oil to each of the hydraulic actuators; and a travel independent valve configured to be switchable between:
a merging position for merging the pressure oil from the first discharge port P1 of the hydraulic pump with the pressure oil from the second discharge port P2 of the hydraulic pump to effect the supply of the pressure oil to the hydraulic actuators; andan independently feeding position for independently effecting the supply of the pressure oil from the first discharge port P1 of the hydraulic pump to the hydraulic actuator of the right-side travel device and the supply of the pressure oil from the second discharge port P2 to the hydraulic actuator of the left-side travel device,the travel independent valve being switched to the merging position in a case of driving the front working device without actuation of either of the right-side or the left-side travel devices, ora case of driving each of the right-side and the left-side travel devices and the front working device concurrently, orbeing switched to the independently feeding position in a case of driving each of the right-side and the left-side travel devices without actuation of the front working device; a load sensing system adapted to control a discharge flow rate of the variable displacement hydraulic pump based on a pressure difference between:
a discharge pressure of the split-flow-type variable displacement hydraulic pump; anda maximum load pressure that is a highest one of load pressures of the hydraulic actuators of the right-side and left-side travel devices and the front working device in any one of a case where the travel independent valve is in the merging position and in a case where the travel independent valve is in the independently feeding position.