The Cause Of The Failure Of The Loader At Work

Aug 29, 2019

We summed up the main causes of the failure of the loader at work. Let me explain it to you today.

1, the system pressure is too low

At the pressure measurement point of the distribution valve, the pressure gauge with a range of 25mpa is connected, so that the engine and hydraulic oil are operated at the normal working temperature and the engine speed is about 1800r/min, and the distribution valve rotary valve is operated to make the bucket backward to the bottom. The pressure shown in the table should be 17mpa. If it is lower than this value, the safety valve should be disassembled to check whether the pilot valve spring is broken, the seal is good, the main spool is stuck, and the orifice is blocked. When there is no problem above, adjust the pressure adjustment screw to make the system pressure reach the normal value.

2, the boom cylinder or the cylinder cylinder leakage

The piston of the boom cylinder or the rotary cylinder is respectively received by the bottom, and the rodless cavity oil pipe is removed, so that the rod cavity of the boom cylinder or the rotary cylinder continues to be filled with oil. If there is more oil leakage from the rodless port (normal leakage should be 鈮30ml/min), the piston seal ring is damaged and should be replaced; the bucket can also be filled with load and lifted to the limit position. The boom lever is placed in the neutral position and the engine is turned off. Observe the sinking speed of the boom (<40mm/h when normal); then, place the boom lever in the up position, if the boom sinks The speed is obviously accelerated, indicating that the internal leakage occurs in the hydraulic cylinder; if the sinking speed does not change significantly, the internal leakage is caused by the distribution valve.

3, distribution valve leakage

The main reasons for the leakage inside the distribution valve are: the main valve core of the total safety valve is stuck; the clearance between the valve stem and the valve body is too large (normal fit clearance is 0.025~0.040mm); the stem or valve body is strained; Damage to the pieces, etc.

4, working gear pump leakage

The internal leakage of the gear pump is as follows: the noise is large during operation, and the higher the engine speed, the greater the noise; a large amount of copper scrap is visible in the oil filter. The gear pump should be disassembled to detect the gear gap (normal value is 0.005~0.115mm) of the gear end face clearance (normal value is 0.100-0.140mm), the radial clearance of the gear (normal value is 0.100~0.200mm), and Check if the seal is good, etc. Repair or replace if it is out of tolerance or damaged.