What faults are prone to occur in the tractor hydraulic system? How to deal with it? Learned not to ask

The hydraulic system is that the tractor provides hydraulic power support for supporting agricultural machines and tools to meet the working state adjustment and power requirements of agricultural machines and tools. Let's talk about the common faults and solutions of tractor hydraulic system.
Composition of tractor hydraulic system

The driving force of the tractor hydraulic system is provided by the diesel engine. The main working parts of the hydraulic system include hydraulic pump, distributor, connecting pipeline, hydraulic cylinder, auxiliary device, etc. According to the different horsepower and design structure of the tractor, the hydraulic system of the tractor is generally divided into three types: split type, semi split type and integral type. The oil pump, oil cylinder, distributor and other components of the split hydraulic system are not installed centrally, but are designed and assembled in different positions of the tractor; The oil cylinder, distributor and control device of the semi split hydraulic system are centrally installed at the rear axle housing, but only the oil pump is installed separately; All components of the integral hydraulic system are centrally installed on the rear axle housing.

Causes of tractor hydraulic system failure
1 aging or wear of hydraulic components
Many precision hydraulic components are used in the tractor hydraulic system, and the tightness of the hydraulic system needs to be maintained all the time. During the long-term operation of the tractor, many hydraulic components will be aged and damaged under frequent working conditions. For example, oil leakage is caused by oil pipe crack and aging of sealing ring; Failure of hydraulic system due to damage of hydraulic oil pump; The function confusion caused by the stuck distributor is caused by the damage of the components of the hydraulic system.
2 improper use and maintenance
In the process of tractor supporting agricultural machines and tools, improper use by the operator is easy to cause the failure of the hydraulic system, such as the driver's overload use of the hydraulic system for a long time; The driver does not pay attention to the inspection of hydraulic temperature; If the driver ignores the abnormal phenomena such as vibration and noise of the hydraulic system, it may cause serious hydraulic system failure. At the same time, users ignore the maintenance of the hydraulic system, do not replace the hydraulic oil in time, and do not clean the filter on time, which will not only cause the wear of the gear pump and the pollutants on the inner surface of the oil pipe, but also cause the poor working state of the hydraulic system and the failure of the hydraulic system.
3. The maintenance of hydraulic failure is not standardized
When the tractor's hydraulic system fails, many drivers repair it without detailed analysis or maintenance ability, which is easy to cause further damage to the hydraulic system; In order to be cheap, the driver looks for an informal small maintenance factory to repair the hydraulic system, or the hydraulic system may be damaged due to improper maintenance. In addition, in the maintenance process, selecting low-quality hydraulic components to replace the faulty parts is not conducive to the stable operation of the hydraulic system and will cause hidden trouble for later use.

Common faults and repair of tractor hydraulic system
1. Abnormal working condition of gear pump
Gear pump is the power source for the operation of hydraulic system. In the working engineering of tractor hydraulic system, the fault of gear pump shows the following three forms: insufficient oil supply or insufficient pressure; No or insufficient oil absorption; The gear pump is burnt.
(1) the possible reasons for the insufficient oil supply or pressure of the gear pump are as follows: the small seal ring is damaged or invalid, resulting in the failure of the sealing and pressure isolation function of the gear pump; The sealing structure between the front cover or shaft sleeve and the gear is damaged; The rubber at the waist of the shaft sleeve is blocked and fails to have the function of sealing and pressure isolation; Oil trapping occurs in the gear pump, resulting in insufficient hydraulic oil output, etc.
(2) the reasons for non oil absorption or insufficient oil absorption of the gear pump include the following points: insufficient hydraulic oil or blocked hydraulic oil pipe; The filter is blocked due to excessive viscosity of hydraulic oil; The oil suction pipe enters the air, etc. For the fault that the gear pump does not absorb oil, the problem of insufficient hydraulic oil should be eliminated first, the quality of hydraulic oil should be checked, the hydraulic oil that does not meet the use requirements should be replaced in time, the filter element should be cleaned regularly, and the air and blockage in the oil circuit should be removed in time.
(3) the burning failure of the gear pump is caused by the high temperature of the gear pump, which may be caused by the high temperature caused by the idling of the gear pump due to the lack of hydraulic oil; Or the abnormal working state of the distributor leads to the failure of the safety valve or return, resulting in the overload of the gear pump for a long time. In addition, too tight assembly of the gear pump will lead to excessive running resistance, which is easy to cause the problem of too high temperature. There are many factors for the fault of the gear pump. According to some statistics, the probability of the fault parts of the gear pump is low.
2. Abnormal working state of hydraulic distributor
There are mainly two forms of frequent faults of the distributor: one is the oil leakage of the distributor, which is mainly caused by the slow lifting or execution of supporting agricultural machines and tools, which is mainly caused by the poor sealing between the valve and the valve hole or valve seat, or the oil leakage caused by the sealing failure caused by the aging of external seals. The second is the stuck valve fault. The stuck valve fault shows that the control valve is stuck in a certain position and cannot move, resulting in the abnormal working process of the hydraulic oil circuit. The reasons for the stuck valve include the temperature rise caused by the high system pressure, the stuck valve and valve hole, or the aged or dirty hydraulic oil, and the control valve is stuck in a certain position due to dirt or foreign matters. For the failure of the hydraulic distributor, replace the aged or damaged seals in time, adjust the supporting relationship between the hydraulic pump and the distributor, and replace the hydraulic oil in time.
3 hydraulic cylinder failure
During the operation of tractor supporting agricultural machines and tools, the work of hydraulic cylinder is usually very frequent. When the hydraulic cylinder reciprocates for a long time, it is easy to cause serious wear of piston or cylinder. Due to the loss of the original matching relationship, the hydraulic cylinder is likely to be stuck at a certain position, resulting in the failure of lifting function. At this time, the piston wearing parts shall be replaced in time and the cylinder block shall be repaired or replaced. In addition, if the hydraulic oil cylinder is idle for a long time in the slack period, and the residual oil film on the surface of the oil cylinder adheres to the oil cylinder due to cementation, resulting in the cylinder being stuck, the foreign matter at the stuck position shall be removed in time, and the oil cylinder will return to its normal use function.
4 hydraulic power steering failure
When the hydraulic power steering fails, the steering wheel of the tractor feels heavy. The main reason for this problem is that the working performance of the safety valve or flow regulating valve decreases, resulting in the reduction of the oil supply of the hydraulic pump, resulting in the significant reduction of the ability of hydraulic power steering. In case of failure of hydraulic assistance, first check whether the hydraulic oil is sufficient, and then replace the pressure spring of safety valve and flow regulating valve in time. If the fault still exists, check the working state of hydraulic pump and repair it if necessary.