The causes and troubleshooting methods of the loader not being able to move

Causes and solutions for the malfunction of loaders not being able to move:

When a zl30e loader was operating at night, suddenly the shift pressure in all gears was too low to move, and the shift pressure in neutral gear fluctuated sharply. The fault was automatically eliminated after a period of rest, but it reappeared after working for a while. As the transmission of this machine has only been in use for a little over two months, the possibility of simultaneous internal leakage from the clutches of all gears is very small. The sharp pressure fluctuations in neutral gear indicate that the pressure of the main pressure regulating valve of the torque converter is unstable or the oil volume from the torque converter is insufficient. At this point, insufficient oil volume indicates that the oil supply to the walking pump is inadequate. The likely cause is that the pump has insufficient oil suction or is damaged.

I. Cause of Fault:

Firstly, the oil suction filter screen of the walking pump was inspected. After removing the filter screen, it was found that the surface of the filter screen was covered with a large amount of aluminum powder, which led to insufficient oil suction by the walking pump. The insufficient oil supply from the walking pump in turn caused the shift pressure to be too low, ultimately resulting in the loader being unable to move. According to the operator's feedback, the oil temperature of this machine has always been high and the traction force is not large. Given the phenomenon that the hydraulic transmission oil with a relatively high oil temperature contains a large amount of aluminum powder, we infer that there might be problems with the pump wheel and turbine of the torque converter.

2. Remove the connecting bolts between the torque converter and the engine, lift out the torque converter and disassemble it for inspection. It was found that the bolts fixing the turbine had loosened, causing the turbine to move axially. After removing the turbine, it was found that the nuts that fixed the pump wheel and the guide wheel were also loose, which could also cause axial movement of the pump wheel and the guide wheel.

At the same time, it was found that the end faces of the pump wheel and the turbine had been ground into a fish-scale shape.

Ii. Exclusion Methods:

When repairing, we first grind the end faces of the pump wheel and guide wheel flat, tighten the nuts of the pump wheel and guide wheel, and clean the pump wheel, guide wheel and turbine shaft and other parts thoroughly.

2. Use a lathe to turn the turbine along the axial direction by 1.5mm, and sharpen and blunt it.

3. After thoroughly cleaning all parts, install the turbine and tighten the turbine bolts.

4. Adjust the clearance between the pump wheel and the turbine properly;

5. Thoroughly clean the transmission housing, the oil suction filter screen and housing of the walking pump, and the return oil filter.

6. Then, install all the components as required and test the machine. At this point, the oil pressure in each gear is normal, the traction force has increased significantly compared to before the repair, and the oil temperature is also normal, indicating that the fault has been eliminated.