Analysis: the stick movement is controlled by the stick reversing valve, and the movement of the stick reversing valve core is affected by the following two aspects: a. the pilot oil control is slow; B. Movement resistance of reversing valve spool and spring return force.
There are two main reasons for the slow control of pilot oil: (a) the pilot oil return back pressure of the stick reversing valve is large, (b) the reset of the stick pilot valve core is slow.
Judgment method:
a. First, check whether the pilot oil circuit of the stick reversing valve is equipped with a one-way throttle valve. If so, first remove the one-way throttle valve for cleaning, unblock the damping hole or cancel the throttle valve core;
b. If the fault still exists or the pilot oil circuit of the stick reversing valve is not equipped with a one-way throttle valve, replace the two pilot rubber hoses of the adjacent swing valve that work normally with the stick valve. If the fault is transferred to the swing, repair the pilot valve. If the fault still exists, it means that the pilot control is OK, and the rest is that the stick reversing valve core is faulty:
Remove the stick reversing valve core, and check whether the valve core can slide freely and whether the valve core return spring is broken (if the valve core is loose).
Failure of some control valves of Kobelco excavator may cause system failure:
I Each reversing valve on the multi-channel valve of the pressure compensation valve is equipped with a pressure compensation valve, and the return oil of each actuator during operation will flow back to the oil tank through the corresponding pressure compensation valve. If a pressure compensation valve core is stuck and cannot be reset, the return oil channel of the corresponding actuator will be closed or reduced, and the return oil of the actuator will generate a large back pressure. Even if the working pressure is enough to 28Mpa, the action of the actuator will slow down.
II. The boom, stick and bucket reversing valves of the oil makeup valve are each equipped with an oil makeup valve. If an oil makeup valve core is stuck and cannot be reset after it is opened or the damping hole of the oil makeup valve core is blocked, the oil makeup valve core will always be in the open position, and the oil inlet circuit and oil return circuit of the corresponding actuator are always connected. If the working pressure of the actuator cannot be established, the actuator will not be able to act, or the actuator can only be lowered slowly by its own weight.
