Excavator common faults and exhaust method: walking motor, two main tubing burst. The motor two main pipe walking hydraulic excavator (A, B) is the main reason often burst speed, double speed valve after the valve failed to return on time, the oil inlet and the oil return port cannot Lianneng, caused by oil pressure transient high. At this point should:
(1) properly increase the speed of double valve spring stretch. After the operation pressure is relieved, the valve core can be smoothly reset under the influence of spring elasticity. But it should be noted that increasing the elasticity of the spring can not simply increase the rate of adding gasket method, it must be detected by the spring elasticity.
(2) grinding double speed valve, burr removal, so that the spool in the valve movement freely, no jam phenomenon.
(3) operations should be standardized. For example, the correct operation of the shift in the course of the excavator's walking is that the excavator must be stopped at any speed, then shifted and then moved.
(2) running deviation. Excavator occurred walking deviation, in determining the technical condition of normal running motor, adjust the tightness of the track under the right circumstances, can make the block inspection as follows:
(1) inspection work walking hydraulic circuit pressure. First check the slow running side, starting from the combination valve, remove the pressure limit valve on the two oil pipes, plug the oil outlet with a plug. Then remove another combination of valve on the two walk tubing, start the engine, driving combination valve plug walking control handle, observe the oil pressure whether it meets the requirements, and then observe another combination of valve (pressure limiting valve) of the A B, whether there is oil outflow hole. If the oil pressure is normal, without oil outflow hole B A, another combination of valve, can be regarded as combination of valve failure; if the normal oil pressure to explain internal leakage phenomenon is serious; if A and B are oil and another combination of valve outflow, two combination valve have collusion. The only way to collude with the shuttle valve is to check the seal of the shuttle valve or replace the shuttle valve.
(2) if the combination valve is working properly, the central swivel can be checked in sequence. There is a lot of oil passages at the central swivel joint, so they are easy to collude with each other. Check method is: A, B oil removal of two of the walking motor and then blocked one of the hydraulic motor A, B tubing; start the engine, hydraulic motor driven valve blocked tubing, check the oil pressure is normal (to confirm the performance of two fill oil valve is intact, A); B hydraulic motor oil hole to observe whether the oil is not blocked. If the oil pressure is not normal, not blocked by A, B oil hole and oil, that the central rotary joint oil seal is not good, the oil has been in collusion with each other, seals to repair or replace the central rotary joint. Second, fourth oil groove central rotary joint is China Unicom A, B oil hole left walking motor, and the third, fifth oil groove is China Unicom A, B oil hole on the right of the walking motor, if it is second, third or fourth, fifth oil tank oil tank collusion collusion, excavator is unusual.
(3) hydraulic cylinder crawling. Hydraulic cylinder piston rod is generated when the main reason is crawling, with the hydraulic cylinder seal and cylinder wall is not good, from the static friction resistance caused by large changes. This phenomenon usually occurs in the new assembly of hydraulic cylinders. After a period of use, the phenomenon of crawling will be reduced to disappear naturally. If the hydraulic cylinder continues to crawl after a period of time, check that the seals are in good condition and are properly assembled.
(4) combination valve rupture of oil inlet pipe. In addition to combination valve working pressure exceeds the set value, the main reason is due to the speed limit valve spool in the valve body activities are not flexible, hysteresis phenomenon card, causing over from the shuttle valve oil cannot open normal speed limiting valve, the poor oil return oil return, resulting in increased resistance, causing instantaneous pressure the pipe burst. As long as the polishing or grinding speed limiting valve, so that the spool is flexible, the fault can be ruled out. The piston rod of
(5) power arm cylinder, bucket rod cylinder and bucket cylinder is extended and closed only. The oil return pressure increases, the tubing joint breaks, and the engine load increases. In addition to the above fault in the normal position of the spool, the main reason is due to the shuttle valve installed reverse. From the analysis of the working principle of the circuit before the combination valve in accordance with their respective different working conditions, working pressure of their oil were attracted by the shuttle valve open, open limit the speed limit valve, open the oil, the entire hydraulic system is in normal working condition, the valve group and all the actuator to the normal feed and return oil. When the edge (the oil valve installed anti shuttle valve after the valve oil group received slip shuttle valve, and the oil inlet valve group received after opening), total return rate limiting valve circuit on not working pressure oil from the shuttle valve to overcome the spring force limiting valve no, the rate limiting oil return valve core is pushed to the position, the speed of the spool in the spring under the action of pressure in the closed position of the total return line. The pressure oil output from the hydraulic pump, because there is no return, the pressure of each pipe of the valve group rises abnormally, causing the tubing rupture. If in this case, pull the reversing valve, the hydraulic cylinder without rod cavity volume, high pressure, but also barely push the piston rod can not be closed. As the total return circuit is blocked, the pressure of the valve group and the tubing is increased abnormally, and the load of the diesel engine is increased. As long as the shuttle valve is properly assembled, the fault can be mentioned and eliminated.
(6) hydraulic pump can not achieve confluence, the excavator does not walk fast. In the correct position, the valve tank solenoid valve mixing valve no delay under the condition of a
