Control valve of hydraulic system for working machine

A control valve of a hydraulic system for a working machine, the control valve comprising:

• a main body including
• a first port configured to be connected through a first fluid tube to a hydraulic actuator,
• a second port configured to be connected through a second fluid tube to the hydraulic actuator,
• a third port configured to be connected through a third fluid tube to a hydraulic pump to output operation fluid,
• a fourth port configured to be connected through a discharging fluid tube to a tank,
• a fifth port configured to be connected through a bypass fluid tube to another downstream control valve,
• a first inner fluid path, a second inner fluid path, a third inner fluid path, a fourth inner fluid path and a fifth inner fluid path connected to the first port, the second port, the third port, the fourth port, and the fifth port, respectively;
• and
• a spool configured to move between a neutral position and a communicating position allowing fluid communication between the second inner fluid path and the fifth inner fluid path or between the first inner fluid path and the fifth inner fluid path, wherein
• the spool includes a communicating hole configured to allow the fluid communication between the second port and the fourth port through the second inner fluid path and the fourth inner fluid path without the fluid communication between the second inner fluid path and the fifth inner fluid path, or between the first port and the fourth port through the first inner fluid path and the fourth inner fluid path without the fluid communication between the first inner fluid path and the fifth inner fluid path, when the spool is in a position between the communicating position and the neutral position.