Common faults and solutions of 4WEH16 electro-hydraulic reversing valve

Common faults and solutions of 4WEH16 electro-hydraulic reversing valve are as follows:

1. Electromagnet related faults

The electromagnet does not move or the reversal is weak

reason:

The power supply voltage fluctuates beyond the rated range (such as lower than 10% or higher than 15% of the rated voltage).

The solenoid coil is damaged (such as short circuit, open circuit or burnt out).

The connection between the solenoid push rod and the valve core is loose or desoldered.

How to deal with it:

Check whether the power supply voltage is stable and adjust it to within the rated range.

Use a multimeter to check the coil resistance and replace the coil if abnormal.

Re-weld the connection between the push rod and the valve core to ensure firmness.

The electromagnet is overheated or burned out

reason:

Too high voltage or too high commutation frequency leads to excessive current.

The gap between the electromagnet and the valve core is too large, causing mechanical friction when closing.

How to deal with it:

Make sure the voltage is within the rated range and reduce the commutation frequency.

Adjust the gap between the solenoid and the valve core to the standard value (usually 0.1-0.3mm).

2. The valve core is stuck or the reversal is unreliable.

Valve core stuck

reason:

The oil is seriously contaminated, and impurities enter the gap between the valve core and the valve body.

Scratches on the surface of the valve core or deformation of the valve body hole lead to increased friction.

Hydraulic clamping phenomenon (the radial unbalanced force of the valve core is too large).

How to deal with it:

Clean the valve body and valve core, replace the hydraulic oil and filter it to NAS level 7 or above.

Repair or replace the scratched valve core and grind the valve body hole to standard size.

An annular pressure equalizing groove is opened on the valve core to reduce the radial unbalanced force.

Sluggish or jerky commutation

reason:

The opening of the control oil circuit throttle valve is too small, causing the valve core to move slowly.

The pressure difference between the two ends of the main valve core is insufficient (such as the setting value of the pre-control pressure valve is too low).

System pressure fluctuates or oil return back pressure is too high.

How to deal with it:

Adjust the throttle opening to the appropriate size (usually 0.8-1.2mm).

Check and adjust the setting value of the pre-control pressure valve (generally not less than 1MPa).

Stabilize the system pressure and reduce the oil return back pressure (such as cleaning the oil return pipeline or replacing the filter).

3. Leakage failure

Internal leakage (internal leakage)

reason:

The matching gap between the main valve core and the valve body is too large or the seal is damaged.

Spring fatigue causes poor valve core reset.

How to deal with it:

Replace the seal or reconfigure the valve core (the gap is controlled at 0.008-0.025mm).

Replace fatigued springs to ensure that the restoring force meets the requirements.

External leakage (external leakage)

reason:

The connecting screws are loose or the sealing surface is scratched.

Pipe joints are loose or seals are aging.

How to deal with it:

Tighten the connecting screws evenly and repair scratches on the sealing surface.

Retighten the pipe joints and replace the aging sealing rings.

4. Other faults

Abnormal system pressure

Phenomenon: The system pressure suddenly drops during reversal or the pressure cannot be established.

reason:

The main valve core is not reversed in place, causing the P, A, B, and T chambers to communicate.

The pre-control pressure valve fails or the control oil line is blocked.

How to deal with it:

Check and repair the main valve core reversing mechanism to ensure flexible movement.

Clean or replace the pre-control pressure valve and clear the control oil line.

noise or vibration

reason:

There are impurities on the electromagnet suction surface or the axis of the armature is offset.

Hydraulic shock causes pipe vibrations.

How to deal with it:

Clean the electromagnet suction surface and adjust the coaxiality between the armature axis and the iron core.

Install an accumulator or double one-way throttle valve in the control oil line to slow down the reversing impact.