Hydraulic system for working machine

A hydraulic system for a working machine, comprising:

• a first output fluid tube connecting between a hydraulic pump to output operation fluid and a first operation valve to change a first pilot pressure of the operation fluid;
• a second output fluid tube connected between the hydraulic pump and a second operation valve to change a second pilot pressure of the operation fluid;
• a switching valve provided in the second output fluid tube;
• a warm-up fluid tube connected between the first operation valve and the switching valve;
• an unload switch;
• a first operation member to operate the first control valve;
• and
• a controller configured to control the switching valve, upon operation of the unload switch, to switch between
• a first position allowing the operation fluid to be drained through the first output fluid tube, the first operation valve, the warm-up fluid tube and the switching valve, and
• a second position allowing the operation fluid to be supplied through second output fluid tube to the second operation valve,
• wherein the controller is configured to control the first operation valve to change an opening aperture thereof upon operation of the first operation member.

A hydraulic system for a working machine, comprising:

• a first output fluid tube connecting between a hydraulic pump to output operation fluid and a first operation valve to change a first pilot pressure of the operation fluid;
• a second output fluid tube connecting between the hydraulic pump and a second operation valve to change a second pilot pressure of the operation fluid;
• a first control valve to control the operation fluid supplied to a first hydraulic actuator in accordance with the first pilot pressure;
• a controller configured to control the first operation valve to change an opening aperture thereof upon operation of a first operation member;
• a switching valve provided in the second output fluid tube;
• and
• a warm-up fluid tube connected between the first operation valve and the switching valve,
• wherein the switching valve is switched between
• a first position allowing the operation fluid to be drained through the first output fluid tube, the first operation valve, the warm-up fluid tube and the switching valve, and
• a second position allowing the operation fluid to be supplied through second output fluid tube to the second operation valve.