CPC E02F 9/2217 (2013.01) [E02F 9/123 (2013.01); E02F 9/2228 (2013.01); E02F 9/26 (2013.01); F15B 13/02 (2013.01); E02F 9/2285 (2013.01); E02F 9/2292 (2013.01); E02F 9/2296 (2013.01)] | 3 Claims |
1. An excavator comprising:
a power take-off;
an engine coupled to the power take-off;
a swing hydraulic pump coupled to the power take-off and driven by the engine;
a swing hydraulic motor driven by hydraulic oil discharged from the swing hydraulic pump;
a first main oil passage that connects a first discharge port of the swing hydraulic pump and a first suction port of the swing hydraulic motor to each other;
a second main oil passage that connects a second discharge port of the swing hydraulic pump and a second suction port of the swing hydraulic motor to each other;
a neutral retention valve that is disposed in the first main oil passage and the second main oil passage and controls passage of the hydraulic oil;
a regenerative energy absorbing device that is coupled to the power take-off and absorbs regenerative energy generated by the hydraulic oil supplied from the swing hydraulic motor to the swing hydraulic pump via a meter-out opening of the neutral retention valve;
a valve control section that controls an area of the meter-out opening based on a state of the regenerative energy absorbing device;
a state quantity acquisition section that acquires a state quantity indicating the state of the regenerative energy absorbing device; and
a device hydraulic pump coupled to the power take-off and driven by the engine,
wherein the valve control section controls the area of the meter-out opening based on the state quantity,
wherein the regenerative energy absorbing device includes the device hydraulic pump,
the regenerative energy includes regenerative torque generated by the swing hydraulic pump,
the state quantity includes consumption torque of the device hydraulic pump, and
the valve control section reduces the area of the meter-out opening when the regenerative torque exceeds the consumption torque.
|