Do You Know How to Solve the Common Failures of Hydraulic Valves?

Both automatic transmission hydraulic system and hydraulic transmission system have a certain chance of failure. Common failures of hydraulic valves are generally divided into two types: display failure of the electric control box and failure of the main valve to open.

 

 

Time out

Regardless of whether the valve opening time is overtime or the valve closing time is overtime, we need to check whether the main valve fully open stroke switch is compressed or whether the valve is open. Some systems may use MHA hydraulic valves and flat face hydraulic quick release couplings.

 

Oil Pump Overload

After resetting the thermal relay, we need to check the oil pump and motor to find out the cause of the overload.

 

There Are Two Signal Inputs for the Three Signals of Opening, Closing and Stopping the Valve at the Same Time

We need to check whether the switch button is damaged or whether there is a short circuit.

 

There Are Two Signal Inputs in the Four Limit Switches at the Same Time

Please check if there is a phenomenon that the limit switch cannot pop up.

 

Two Signals of Low Voltage and High Voltage Switch Are Input at the Same Time

We can first confirm whether the pressure range of the low pressure open high pressure switch is correct, or replace the pressure switch.

 

Two Signals Are Input at the Same Time in Linkage Open Valve and Close Valve

Please check whether the rotary switch is damaged or whether there is a short circuit.

 

Bypass Valve Overload

First of all, the switch signal of the side valve may not be adjusted in place, causing the side valve to be fully open/closed, and the travel switch is still not pressed. We should adjust the travel switch of the side valve in place. Second, we need to check whether the bypass valve is stuck. If a stuck phenomenon occurs frequently, we recommend replacing galvanized pipe fittings or brass pipe fittings.

 

 

The Main Valve Cannot Be Opened

First, please check whether there is a flat pressing signal. Check whether the bypass valve is fully opened, and ensure that the pressure behind the valve is equal to the pressure in front of the valve (within 30%). If the pressure after the valve reaches the requirement, the flat pressure signal device may be faulty or damaged.

 

Second, we should check whether the guide vanes are fully closed, and check the signal of the electric control box that the guide vanes are fully closed.

 

Third, the 380V power supply needs to be checked for correctness to ensure that the motor is rotating forward.

 

Fourth, we need to check the lock out signal of the cylinder. On the one hand, if the lock is pulled out, but the limit switch is not pressed, we need to adjust the limit switch to the pressed state. On the other hand, if the lock is not pulled out, we should check whether the locking solenoid valve is damaged, whether the system is under pressure, whether the locking cylinder has mechanical problems, or the nitrogen pressure of the pull-lock accumulator is insufficient. Generally, pressure gauge ball valves are equipped with pressure gauge snubber.

 

Fifth, we should check which gear the knob switch is switched to.

 

Sixth, we need to check whether the open valve solenoid valve is stuck with iron chips. The stuck iron chip will cause the solenoid valve to fail to operate.

 

 

There may be some differences in the design of each manufacturer, so the above methods are for reference only. If you are interested in hydraulic power transmission and hydrostatic drive transmission, please follow us.