A Komatsu excavator was equipped with a crushing hammer working device, and then an unspecified crushing hammer was installed during one construction. The att pilot valve was stuck several times in a short time, and the att did not act.
Analysis of no action of the breaking hammer maintained by Komatsu excavator:
During on-site maintenance, it was found that the user's Excavator had an alarm mark of "abnormal selection pressure sensor", and all att handles of the machine had no action. Through further inspection, it was found that the pilot valve core of ATT handle was stuck, and the oil return filter element was attached with iron filings and other yellow powder.
The user introduced and installed EDT (Canadian brand, assembled in Shandong) through the sales personnel. After installation, the intermittent use time was more than 30 hours, but the special overflow valve was not installed, resulting in improper crushing pressure restriction; The special oil return pipe of the crusher does not directly return to the hydraulic oil tank, but passes through the radiator oil return tank; The flow rate when the crusher is used is not adjusted. The flow rate used is 294, but the actual flow rate should not exceed 230.
Analysis and treatment of no action of the breaking hammer maintained by Komatsu excavator:
1. Check the oil return filter element for iron filings and yellow powder (suspected to be powder such as brake pads); Check that the att pilot valve is stuck and clean it;
2. Replace hydraulic oil and oil return filter element; Test run to check whether there is any abnormality in the action and sound. It is determined that the hydraulic system of the excavator is damaged, but there is no major abnormality at present. The machine can continue to be observed and used
3. The crusher manufacturer shall check the crusher and confirm that there is no fault; The maintenance personnel shall continuously observe the machine for 2 hours and replace the hydraulic oil and filter element again. (adjust the flow to 230)
The second day after the machine was used, the att pilot valve was stuck again, and it was used normally after cleaning; On the third day of use, the machine shall be inspected at the construction site. The machine shall use the bucket and work normally. There shall be no iron scraps in the filter; The crusher manufacturer is replacing a new crusher for the user on site, changing the oil return pipeline, and subsequently adding an oil outlet overflow valve for the machine.
