Add: #6 Yanshan Rd,Xiepu town,Zhenhai district,Ningbo city ,Zhejiang province China
Application of hydraulic transmission system of loader main working device hydraulic system, hydraulic steering system, hydraulic system transmission moment, it has the advantages of compact structure, flexible operation, stable operation, convenient operation and the advantages of lightweight, but because the hydraulic transmission is using liquid as power transmission medium, it is prone to leakage, operation time after a long, but also prone to overheating, inability to work, internal components damage. Failure of hydraulic transmission is sudden and concealment, and involves more components, hydraulic motor fault diagnosis and troubleshooting to bring great difficulties, so the maintenance of the hydraulic system, the foundation must understand the working principle and the correct analysis of failure causes in order to ensure the quality of maintenance. After years of experience in production practice, I have accumulated some experience and wrote it to discuss with you, hoping to play a guiding role in overhauling hydraulic transmission system. Taking the hydraulic system of a ZL50C loader often failed as an example, this paper introduces the working principle of hydraulic transmission, and analyzes the common fault phenomena in its working process.
Fault diagnosis and elimination of hydraulic system of 1 and ZL50C working equipment
The main cause of the two failures is that the oil pressure is low, and the main cause of the low pressure is the clogging and leakage. The smooth and sealed oil well is a guarantee for the normal operation of the system. Blockage and leakage are the most common hydraulic transmission failures. Therefore, checking hydraulic transmission failures generally starts with hydraulic oil circuits. The following is the diagnosis and elimination of the different faults in the hydraulic system of the ZL50C working device. ZL50C loader bucket full, engine rated speed, lifting time should be less than 7S arm, turning forward time should be less than 2.5s, higher than the corresponding time is slow; working device hydraulic system pressure is 17Mpa, the pressure is less than the low pressure system. The fault of the hydraulic system of the working device is mainly shown in two aspects: the lifting of the arm is slow, weak or no action, and the turn of the bucket is slow, weak or no action.
The working principle of the hydraulic system of 2 and ZL50C working equipment
ZL50C hydraulic system consists of a pump, distribution valve (valve safety valve, valve by rotating bucket, bucket cavity double acting safety valve, safety valve, rotating bucket cavity boom spool integration), turningcylinder boom cylinder and oil tank.
The pressure oil advanced rotary spool valve and the rotary bucket slide valve have three positions. The spool valve is operated to enable the right or left position of the slide valve to realize the backward and forward movements of the bucket respectively. When the middle position of the spool valve is placed, the pressure oil enters the slide arm valve of the boom. The movable arm spool valve has four positions. The operation spool, as shown in figure -1, from the right to the left four bits, can realize the lifting, closing, falling and floating actions of the boom, respectively. The total system safety valve valve limits the total pressure distribution of the whole system, double acting safety valve, rotating bucket cavity respectively to fill oil to the bucket from the large cavity, cavity and overload protection. The oil path of the movable arm slide valve and the rotating bucket slide valve adopts interlocked connecting oil path, which can achieve faster operation speed with small flow. The ZL50C loading device using sequential circuit of hydraulic system, the oil inlet passage mechanism according to the order, can only pump in sequence to a fuel supply mechanism. During the working process, the transmission hydraulic oil is sucked from the bottom of the oil tank by the oil filter, and the hydraulic oil from the oil pump is input into the distribution valve with a certain pressure.
3. failure phenomenon:
The lifting arm is slow, weak or no action, and the turning bucket is turned to normal in the hydraulic system of the working device, for example, the lifting arm is slow, weak or no action, and the turning bucket is turned normal. From the work principle is not difficult to see that the bucket flip is working, the working pump and the general safety valve is working properly, they provide to the system pressure enough, at the same time that the end of the pipe and the oil pump into the oil filter and the oil tank volume, no problem. At this time, only check the arm slide valve, the arm cylinder, the arm part of the oil pipe, and its seal.
(1) the leakage of the hydraulic system is usually produced after a period of time. From the surface phenomenon, it is caused by the failure, damage, extrusion or sealing surface of the seal. The main reasons are: oil contamination, improper sealing surface roughness, unqualified sealing grooves, loosening of pipe joints, enlargement of mating parts, excessive oil temperature, deterioration of sealing rings or improper assembly. Leakage is divided into internal leakage and external leakage, usually starting from the leakage of leakage first check.
(2) can be easily eliminated but not easy to diagnose faults of several components need to check the check circuit plug, so we only need to often make the rules, remove the tubing, cleaning boom spool valve body, valve rod and related components to remove oil, clean and dry with compressed air blowing.
Treatment of A leakage fault
Diagnostic method: the outlet leakage of the reducer is usually observed by the naked eye. First, check whether the oil pipe has ruptured, whether the pipe joint is loose, whether the seal is damaged, failed or extruded. Inspect the joint between cylinder head and cylinder, whether there is any leakage between the piston rod and cylinder head guide sleeve, and check the scraping condition of the piston rod. Troubleshooting: fastening socket bolts, replace the seals, piston rod injury serious to re chrome treatment or replacement.
Treatment and diagnosis method of B internal leakage fault
The leakage of this part is mainly caused by the leakage of the sliding valve and the cylinder in the oil cylinder. The internal leakage is hidden inside the valve and cylinder, and it is not easy to check. But we can use some auxiliary methods to judge the leakage.