Diagnosis and detection of the fault that the bucket of the ED600T Ding underground excavator cannot be leveled

During the muck removal construction of the Changliangshan Tunnel, the ED600T underground excavator was hit by a tunnel collapse. As a result, the bucket could not maintain a horizontal position when loading and lifting materials, and the movement of the bucket was out of control, causing severe scattering of stones and preventing normal muck loading.

Diagnosis and analysis process

To identify the cause of the malfunction, we first inspected the damaged parts on the machine's exterior and promptly repaired them. Then, through the automatic monitoring display screen and microcontroller in the cab, the pressure variation values of the main control valves in the hydraulic system with the load and the pressure values of the entire system were observed, inspected and adjusted, but no abnormal phenomena were found. Finally, the operation of the unique device in the hydraulic system of this machine - the cartridge valve - was analyzed. One of the functions of the cartridge valve is to control the automatic leveling action of the bucket. During the lifting process of the bucket, the Angle of the bucket is constantly corrected through the automatic leveling control of the hydraulic cartridge valve group, keeping it always in a horizontal state to prevent the stones from falling. The automatic leveling function is achieved by converting the displacement signal into an electrical signal through the sensor installed in the hydraulic cylinder and transmitting it to the automatic leveling control module for control.

The working principle of the automatic leveling module is as follows: There are two automatic leveling modules on the underground excavator. One module is installed on the lifting cylinder, and the other is installed on the bucket cylinder. These two modules alternately function when the bucket is lifted or lowered to keep the bucket level. When the bucket filled with stone materials is lifted to a certain height, the automatic leveling module switch on the lifting cylinder releases the electromagnet and sends a signal to the solenoid valve of the rapid unloading system, and the bucket automatically discharges the stone materials. When the bucket drops to a certain height, the switch of the automatic leveling module on the bucket cylinder releases the electromagnet, cutting off the electrical signal, and the bucket level device does not function.

Based on the function of the hydraulic cartridge valve and the working principle of the automatic leveling control module, it is initially determined that the inability of the underground excavator bucket to be level is caused by a malfunction of the automatic leveling device, that is, the control module.