With the development of economy, the relative shift of rural labor force and the relative concentration of food production. Demand for medium-sized tractors such as Shanghai 50, Shanghai New Holland, and Jiangsu Qingjiang has increased, and intensive agricultural operations have been promoted. It has played a very good role in the use and promotion of cultivated land. In the production operation, the tractor's hydraulic suspension system is prone to failure. This greatly affected production. Analyze the failures that often occur in hydraulic suspension systems: When the tractor suspends the implement, the lifting is slow or cannot be promoted; the pressure of the system during the lifting is unstable and there is jitter or noise. Open the tank and check for bubbles. The temperature of the hand-touch pump increases. At this time, it should be seen whether the oil level in the fuel tank is too low and the viscosity of the oil is too large. At the same time, see if the oil filter or suction pipe is blocked; whether the suction connector is tightened; if the seal ring is damaged; whether the self-tightening oil seal of the gear pump is damaged. Identify problems and promptly clean up and replace parts. If the condition of oil absorption is normal, the lifting of farm implements will be slow or impossible. Increased without a farm tool but the pump temperature increased faster. At this time, it should be checked whether the small seal is worn out due to excessive wear of the sleeve. Or whether the face seal of the sleeve is damaged. These make the end of the oil pump seal and pressure loss, resulting in internal leakage; the other is the rubber sleeve waist clogging retracted into the hole, will not achieve the sealing pressure, resulting in pressure oil leakage; or due to the oil pump inside the cover The self-tightening of the oil seal causes internal leakage. Find the cause of the above failure and replace the components in time. If the temperature of the pump rises rapidly and there is noise, then the gear pump may be damaged. The reason for this phenomenon is that the gear pump is not able to suck oil or suck enough oil for a long time. Such a lack of lubrication generates friction and burns; another cause is misuse of the lifter, which overloads the gear pump and causes burnout. Then, the assembly is too tight and burns due to excessive turning resistance. When the riser controls failure or oil leakage and check valve, the farm tool cannot be upgraded. The search method is to see if the connection between the joystick and the slide valve is caused by the wear and the failure of the spring, the handle positioning and the limit failure. Causes of oil leakage: External leaks are caused by the deterioration of the seal rings; internal leaks are found by the seals of the valves and the valve holes or valve seats. The main reason for the valve may be improper maintenance, the hydraulic oil is dirty, the clearance between the valve and the valve hole is too small or caused by corrosion. When the piston is stuck in the cylinder, the implement cannot be raised or lowered. The reason is that the piston is not used for a long time in the cylinder, and the oil film remaining on the surface of the cylinder is cemented and stuck. Can be used for flushing with gasoline or alcohol; or metal piston ring and cylinder surface corrosion; or hydraulic oil contains impurities, stuck into the gap and cause the piston to die. When the joystick is moved to the lowered position, the hanging implement remains at its original height and cannot be lowered. The method of inspection is to start from whether the connecting pin of the handle shaft and the positioning block or the control valve is broken. If this is the case, the handle is pulled to the down position, but the control valve does not move and the down oil passage is blocked, so that the implement cannot land. The troubleshooting method is to turn the adjusting screw clockwise so that the valve opens completely. Observe whether the farm implement lands or not. Another reason is to make the tractor safe on the road and the need for maintenance. When the farm implement is lifted, the operator often locks the inner lift arm in a lifting state by using a locking shaft. The locking shaft is not pulled to the disengaged position before the handle is pulled down to land the implement. So farm tools can't land. The search method is to pull the locking shaft to the disengaged position to see if the hanging implement is landing. If it is not for the above reasons, it may be that the piston is stuck in the raised position. If the card is not severe, the suspended farm tool can be pressed down manually to help it land. If the piston is very severely stuck, it is not possible to force the implement with artificial force. This can easily damage the hydraulic system of the tractor. There is also a phenomenon that the tractor is advanced, the raised agriculture has an automatic sinking phenomenon, and the joystick automatically returns to the neutral position. The reason for this phenomenon is that the control valve or the control valve is excessively worn and causes an increase in the fitting clearance. , resulting in oil leakage, so that in the neutral position can not be tightly sealed in the pressure oil in the cylinder; In addition, if the cylinder leaks, and the pipeline connected to the pressure chamber of the cylinder, valve or mating surface leakage, this failure will also occur . In short, when the tractor's hydraulic device fails, it should be searched for the cause of the fault. If the internal pressure of the gear pump fails to establish normal pressure, or if the piston and pump body of the piston pump are severely worn, resulting in insufficient oil supply, the crankshaft may be disassembled at the appropriate location to observe the oil pump condition of the oil pump. If using a pressure gauge or a dedicated tester, it is more accurate.
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