Patent ID: 8720196

Claim:
A controller of a hybrid construction machine, comprising: a variable displacement type of a main pump, a circuit system connected to the main pump and comprising a plurality of operated valves, a neutral channel guiding discharge oil of the main pump toward a tank when all the operated valves provided in the circuit system are maintained in a neutral position, a throttle provided in a portion of the neutral channel downstream of a most-downstream operated valve of the operated valves for generating a pilot pressure, a pilot channel guiding a pressure generated between the most-downstream operated valve and the throttle, a regulator connected to the pilot channel and controlling a tilting angle of the main pump, and a pressure sensor detecting a pressure in the pilot channel, the controller of a hybrid construction machine, comprising: an on/off valve that is provided in a portion of the neutral channel between the most-downstream operated valve and a throttle for generating a pilot pressure, and is maintained in an open position under normal conditions and switched to a closed position when a pilot pressure in the pilot channel reaches a set pressure or higher and the main pump ensures a standby flow rate; a variable displacement type of a sub-pump connected to a discharge of the main pump; an electric motor for rotating the sub-pump; an assist hydraulic motor that rotates the electric motor; a solenoid valve that is provided in a connection channel between the main pump and the assist hydraulic motor and performs closing/opening operation; and a controller unit, wherein the pilot channel is connected to an upstream side of the on/off valve, and the controller unit closes the on/off valve and switches the solenoid valve to an open position when determining, based on a pressure signal from the pressure sensor, that the main pump is discharging a standby flow rate.