The pilot pump is the control oil source of the excavator hydraulic system,and the vast majority of them are external gear pumps.It is generally installed at the rear end of the main hydraulic pump,driven coaxially by the main pump,and specifically provides low-pressure control oil,which is equivalent to the"control power supply"of the hydraulic system.It does not directly drive the oil cylinder or motor.The low-pressure oil output is supplied to the operating handle,foot valve,and safety lock solenoid valve,which drives the main control valve spool to change direction.Only then...