Oil does not enter the cylinder and does not connect the cylinder block to the oil pressure circuit, but the piston rod does not move after the operation command is issued; when the pressure gauge is not connected near the oil port of the cylinder block, the pressure will not be displayed. The reasons for this are as follows:
(1) The reversing valve is not reversing. Reason: The reversing valve is poorly lubricated, the spring is stuck or damaged, and the sliding position is stuck by oil stains or impurities in the machine.
(2) Oil, mud and other substances in the machine block the intake and exhaust holes of the electromagnetic pilot valve, resulting in improper sealing of the pilot valve, stuck movable iron core, and abnormal circuit. These phenomena will make the reversing valve unable to change direction normally.
(3) Circuit failure: control circuit failure, electromagnetic coil failure.
Before checking for circuit faults, turn the manual knob of the diverter valve to see if the diverter valve can still be reversed at rated air pressure. If it can be reversed, the circuit is faulty. You can choose to measure the voltage value of the solenoid coil with an electricity meter to check whether the voltage value meets the standard voltage. If the voltage is too low, check the power supply of the control circuit and the relevant limit switch circuit.
If the reversing valve cannot change the direction under the rated voltage, it is necessary to check whether the connector (plug) of the solenoid coil is loose or has poor contact. The specific method is to pull out the plug and test the resistance of the teaching coil. If the resistance is too large or too small, the solenoid coil has been damaged and should be replaced immediately.
(4) There is no oil supply in the system. Check and troubleshoot pumps, valves and other components.
