Hydraulic drive device for construction machine
A hydraulic drive device for a construction machine includes an engine stopping unit and a discharge rate control unit. The engine stopping unit stops the engine when a predetermined state of the construction machine has continued for a predetermined period of time. The discharge rate control unit controls a discharge rate control pressure being input to the regulator, when an exhaust emission control device performs regeneration control, or performs warm-up control, and the gate lock lever is in the open position.
1. A hydraulic drive device for a construction machine, comprising:
a variable displacement hydraulic pump;
a regulator that controls a discharge rate of the variable displacement hydraulic pump;
an engine that drives the variable displacement hydraulic pump;
a control valve that controls a direction and rate of flow of pressurized oil supplied to a hydraulic actuator;
an operating lever device that is supplied with pressurized oil discharged from a pilot pump and generates a pilot pressure applied to the control valve;
a gate lock lever that is provided near a side of an operator's seat in the construction machine;
a gate lock valve that shuts off a supply line connecting the pilot pump and the operating lever device when the gate lock lever is in an open position in which the gate lock lever opens a boarding entrance;
an engine stopping unit that stops the engine when a predetermined state of the construction machine has continued for a predetermined period of time;
a discharge rate control unit that controls a discharge rate control pressure being input to the regulator, when an exhaust emission control device performs regeneration control, or performs warm-up control, and the gate lock lever is in the open position;
a control pressure detecting unit that detects a control pressure which is supplied by the discharge rate control unit to operate the regulator, or a discharge rate detecting unit that detects a discharge rate of the variable displacement hydraulic pump; wherein:
the engine stopping unit stops the engine when a pressure value of the control pressure to the regulator which is detected by the control pressure detecting unit is lower than a predetermined pressure value, or when the discharge rate of the variable displacement hydraulic pump which is detected by the discharge rate detecting unit is lower than a predetermined discharge rate.
2. The hydraulic drive device according to claim 1 , wherein the predetermined discharge rate is a discharge rate lower than a lower limit for use in the construction machine.