A method and apparatus are presented. An active flow control system comprises a flow control valve, a manifold, and a temperature control system. The flow control valve is configured to control a flow of air into the manifold. The manifold is operatively connected to a number of actuators. The temperature control system is configured to heat at least a portion of the flow of air.

A valve includes a valve housing (2) for transport of a heatable fluid such as hydraulic oil. The valve housing has at least one utility connection (A, B), at least one pressure supply connection (P), and at least one return connection (T1, T2). A control slide (6) is guided in the valve housing (2) in a longitudinally displaceable manner. In at least one position of the control slide (6), the pressure supply connection (P) is at least partially separated from the utility connection (A, B), and the heatable fluid arrives, proceeding from this pressure supply connection (P) and via a heat-emitting connection in the control slide (6), at the at least one return connection (TI, T2) as a loss volume flow. The loss volume flow serves as a heat source and heats at least regions of the control slide (6).

A valve includes a valve housing (2) for transport of a heatable fluid such as hydraulic oil. The valve housing has at least one utility connection (A, B), at least one pressure supply connection (P), and at least one return connection (T1, T2). A control slide (6) is guided in the valve housing (2) in a longitudinally displaceable manner. In at least one position of the control slide (6), the pressure supply connection (P) is at least partially separated from the utility connection (A, B), and the heatable fluid arrives, proceeding from this pressure supply connection (P) and via a heat-emitting connection in the control slide (6), at the at least one return connection (TI, T2) as a loss volume flow. The loss volume flow serves as a heat source and heats at least regions of the control slide (6).

A working machine includes a branched tube connected to a branched portion branching from an operation fluid tube, a plurality of input tubes connected to the second actuator valves, a plurality of output tubes connected to a pressure receiver portion of the second hydraulic device, a main tube connected to the third actuator valve, and a relay device, and the relay device includes a plurality of input ports connected to the plurality of input tubes, a plurality of output ports connected to the plurality of output tubes, a plurality of first flow lines connecting between the plurality of input ports and the plurality of input ports, a main port connected to the main tube, a branched port connected to the branched tube, and a second flow line arranged between the plurality of first fluid lines to connect between the main port and the branched port.

A working machine includes a branched tube connected to a branched portion branching from an operation fluid tube, a plurality of input tubes connected to the second actuator valves, a plurality of output tubes connected to a pressure receiver portion of the second hydraulic device, a main tube connected to the third actuator valve, and a relay device, and the relay device includes a plurality of input ports connected to the plurality of input tubes, a plurality of output ports connected to the plurality of output tubes, a plurality of first flow lines connecting between the plurality of input ports and the plurality of input ports, a main port connected to the main tube, a branched port connected to the branched tube, and a second flow line arranged between the plurality of first fluid lines to connect between the main port and the branched port.

A hydraulic system for a working machine includes a hydraulic pump to output an operation fluid, a hydraulic device to be operated by the operation fluid, an operation member to be operated, a first operation valve to regulate a pressure of the operation fluid in accordance with operation of the operation member, and a pressure supplying portion to supply a first counteracting pressure of the operation fluid against a first operation pressure, the first operation pressure being a pressure of the operation fluid regulated by the first operation valve.

A work machine is provided. The work machine includes a changeover valve capable of disabling area limiting control by bypassing an area limiting control solenoid proportional valve disposed in a pilot line through which pilot pressure generated by a hydraulic pilot type operation device is guided to a directional control valve and the work machine can perform the area limiting control while ensuring response of a work implement. When a first fluid temperature T1 is higher than a first predetermined temperature Ta and a control changeover switch 66 specifies disabling of the area limiting control, a controller brings a plurality of changeover valves into a bypass position. When the first fluid temperature T1 is equal to or lower than the first predetermined temperature Ta, the controller brings the changeover valves into a communication position and places the solenoid proportional valves in a fully open position.

A work machine is provided. The work machine includes a changeover valve capable of disabling area limiting control by bypassing an area limiting control solenoid proportional valve disposed in a pilot line through which pilot pressure generated by a hydraulic pilot type operation device is guided to a directional control valve and the work machine can perform the area limiting control while ensuring response of a work implement. When a first fluid temperature T1 is higher than a first predetermined temperature Ta and a control changeover switch 66 specifies disabling of the area limiting control, a controller brings a plurality of changeover valves into a bypass position. When the first fluid temperature T1 is equal to or lower than the first predetermined temperature Ta, the controller brings the changeover valves into a communication position and places the solenoid proportional valves in a fully open position.

A hydraulic system includes an output fluid tube connected to a hydraulic pump to output operation fluid, and an unload valve to be switched to output operation fluid or to stop outputting operation fluid, the unload valve being connected to the output fluid tube. The hydraulic system includes a hydraulic actuator to be actuated by operation fluid, a control valve to control operation fluid to be supplied to the hydraulic actuator with use of a pilot fluid that is operation fluid applied to a pressure-receiving portion of the control valve, a pilot fluid tube connected to the pressure-receiving portion of the control valve, an operation valve to change a pressure of the pilot fluid to be applied to the pilot fluid tube, and a warm-up fluid tube connected between the unload valve and the pilot fluid tube.

A hydraulic system includes an output fluid tube connected to a hydraulic pump to output operation fluid, and an unload valve to be switched to output operation fluid or to stop outputting operation fluid, the unload valve being connected to the output fluid tube. The hydraulic system includes a hydraulic actuator to be actuated by operation fluid, a control valve to control operation fluid to be supplied to the hydraulic actuator with use of a pilot fluid that is operation fluid applied to a pressure-receiving portion of the control valve, a pilot fluid tube connected to the pressure-receiving portion of the control valve, an operation valve to change a pressure of the pilot fluid to be applied to the pilot fluid tube, and a warm-up fluid tube connected between the unload valve and the pilot fluid tube.