Work machine

A work machine comprising:

• a main circuit that supplies a working fluid delivered from a pump to an actuator;
• a control valve that is provided in the main circuit, and controls a flow of the working fluid supplied from the pump to the actuator;
• a pilot circuit that introduces part of the working fluid delivered from the pump to a pilot pressure receiving section of the control valve;
• a first pressure reducing valve that is provided in the pilot circuit, and reduces a pressure of the working fluid delivered from the pump to generate a pilot primary pressure;
• a second pressure reducing valve that is provided in the pilot circuit, and reduces the pilot primary pressure to generate a first pilot secondary pressure acting on the pilot pressure receiving section of the control valve;
• a bleed-off passage that connects the pump and a tank;
• a pilot-driven bleed-off valve provided on the bleed-off passage;
• a third pressure reducing valve that is provided in the pilot circuit, and reduces the pilot primary pressure to generate a second pilot secondary pressure acting on a pilot pressure receiving section of the bleed-off valve;
• an operation lever that operates the actuator;
• and
• a controller that controls the third pressure reducing valve on a basis of operation by the operation lever, wherein
• the bleed-off valve has:
• a spool that is moved in an axial direction by the second pilot secondary pressure generated by the third pressure reducing valve;
• a valve body that houses the spool slidably;
• and
• a restrictor that gives a resistance to the working fluid passing therethrough,
• a moving area of the spool in the axial direction has a first moving area where an opening area of the restrictor changes stepwise, and a second moving area where the opening area of the restrictor changes continuously,
• the controller is configured to
• control the third pressure reducing valve such that the spool is positioned in the first moving area in a case the actuator is not being operated by the operation lever, and
• control the third pressure reducing valve such that the spool is positioned in the second moving area in a case the actuator is being operated by the operation lever with an operation amount greater than a predetermined value set in advance, and
• the restrictor has a plurality of restricting holes that gives a resistance to the working fluid passing through in a case the spool is positioned in the first moving area.