| CPC E02F 9/2235 (2013.01) [E02F 9/22 (2013.01); E02F 9/2203 (2013.01); E02F 9/2228 (2013.01); E02F 9/2292 (2013.01); E02F 9/2296 (2013.01); F15B 11/00 (2013.01); F15B 11/02 (2013.01); F15B 11/028 (2013.01); F15B 11/042 (2013.01); F15B 11/044 (2013.01); F15B 11/16 (2013.01); F15B 21/087 (2013.01)] | 2 Claims |
|
1. A work machine comprising:
a track structure;
a swing structure swingably attached onto the track structure;
a work device attached to the swing structure;
a hydraulic operating fluid tank;
a hydraulic pump of a variable displacement type that sucks in a hydraulic operating fluid from the hydraulic operating fluid tank and delivers the hydraulic operating fluid;
a regulator that controls capacity of the hydraulic pump;
an actuator that drives the work device;
a swing motor that drives the swing structure;
an actuator directional control valve that controls flow of a hydraulic fluid supplied from the hydraulic pump to the actuator;
a swing directional control valve that controls flow of the hydraulic fluid supplied from the hydraulic pump to the swing motor;
operation devices to make an instruction of operation of the actuator and the swing motor; and
a controller that controls the regulator, the actuator directional control valve, and the swing directional control valve according to an input amount of the operation devices, wherein
the work machine includes
a first pressure sensor that senses a pump pressure that is a delivery pressure of the hydraulic pump,
second pressure sensors that sense an actuator meter-in pressure that is a pressure on a meter-in side of the actuator,
third pressure sensors that sense a swing meter-in pressure that is a pressure on a meter-in side of the swing motor and a swing meter-out pressure that is a pressure on a meter-out side of the swing motor, and
posture sensors that sense posture of the swing structure and the work device,
a meter-in opening and a meter-out opening are formed of a same valve disc in each of the actuator directional control valve and the swing directional control valve,
the actuator directional control valve is formed in such a manner that the meter-in opening becomes smaller than the meter-out opening with respect to valve displacement,
the swing directional control valve is formed in such a manner that the meter-out opening becomes smaller than the meter-in opening with respect to valve displacement, and
the controller is configured to
calculate an actuator target flow rate that is a target value of a flow rate of the hydraulic fluid supplied from the hydraulic pump to the actuator on a basis of the input amount of the operation devices,
calculate a swing target flow rate that is a target value of a flow rate of the hydraulic fluid supplied from the hydraulic pump to the swing motor on the basis of the input amount of the operation devices,
calculate a pump target flow rate that is a target value of a delivery flow rate of the hydraulic pump on a basis of the actuator target flow rate and the swing target flow rate,
calculate a target meter-in opening area that is a target value of a meter-in opening area of the actuator directional control valve on a basis of the actuator target flow rate, the pump pressure, and the actuator meter-in pressure,
calculate target torque that is a target value of input torque to the swing motor on a basis of the input amount of the operation devices and output values of the posture sensors,
calculate a swing target meter-out pressure that is a target of the swing meter-out pressure on a basis of the target torque and the swing meter-in pressure,
calculate a target meter-out opening area that is a target value of a meter-out opening area of the swing directional control valve on a basis of the swing target meter-out pressure and the swing meter-out pressure,
control the regulator according to the pump target flow rate,
control the actuator directional control valve according to the target meter-in opening area, and
control the swing directional control valve according to the target meter-out opening area.
|