Agricultural Combine Harvester 200lpm Directional Control Valve

Operation and maintenance of hydraulic system of agricultural combine harvester

The hydraulic system has many advantages and is widely used in various machinery, but if the use method and maintenance are improper, various failures will occur, and even affect production. Therefore, correct use and maintenance are important factors to ensure the service life of the hydraulic system and ensure stable, sensitive and reliable work. Based on our many years of experience in agricultural machinery hydraulic systems, the main reasons for failures are analyzed below and their maintenance methods are proposed.

01Prevent contamination of hydraulic oil

The pollution of hydraulic oil refers to the mixing of air, moisture, and various solidified materials from the outside, and the use of corroded metal powder, paint and other debris will damage the seal. Oil contamination will aggravate the wear between the relatively moving parts in the hydraulic components, causing the throttle orifice, the clogging of the filter element or the spool valve to jam, and the hydraulic components will not work properly. Therefore, various measures must be adopted to prevent or reduce oil contamination.

In daily use, the main methods to prevent oil contamination are:

① When installing pipelines and joints, they must be thoroughly cleaned and kept clean;

②It is forbidden to wipe with fabric with fibers (such as cotton yarn) when disassembling and cleaning various hydraulic components;

③Check the fuel tank cap, require reasonable sealing, and whether the vent holes are blocked;

④ The seal must be reliable. When replacing, it is forbidden to use oil-resistant seals and hoses;

⑤ The hydraulic oil filter element should be checked frequently, and if it is damaged, it should be replaced in time;

⑥ The oil should be changed regularly. After 400 hours of work, the oil should be changed and the filter element should be replaced. If you continue to use it, the oil will reduce the lubricating performance and may appear acidic, causing corrosion of the metal parts in the hydraulic system.

02 Prevent air from entering the hydraulic system

The oil used in the hydraulic system has very little compressibility and can be considered as incompressible under normal circumstances. But the compressibility of air is very large, so even if there is a small amount of air in the hydraulic system, its influence is also great. The air mixed in the oil will escape from the oil at low pressure and generate bubbles. Cavitation is formed. When in the high pressure zone, these bubbles are quickly broken under the action of the pressure oil, and are compressed sharply, causing noise in the hydraulic system. At the same time, when the gas is suddenly compressed, it will release a lot of heat, which will cause local Overheating accelerates the increase in oil temperature and damages hydraulic components.

In daily use, the methods to prevent air from entering the hydraulic system are:

① Check whether the oil is sufficient, and it is strictly forbidden to use it without oil;

② Keep good sealing of the pipe joints, especially the oil suction pipe. If the sealing is not good, air will be sucked into the hydraulic system.

03 Prevent excessive oil temperature

The working temperature of hydraulic system oil is generally within the range of 30 degrees to 80 degrees. Excessive oil temperature will have a series of adverse effects on the system, such as decreased viscosity, increased leakage, decreased volumetric efficiency, and unstable flow speed. Causes the gap change between the moving amplitudes with different thermal expansion coefficients, and even jams, etc., which will cause the oil to deteriorate, the seals are aging, and the sealing performance is reduced.

From the perspective of use and maintenance, the following issues should be noted:

① Always maintain the correct oil level in the oil tank so that the oil has enough circulating cooling oil;

② When the machine is not working, lower the header, reel and unloading pipe;

③ Choose oil with correct viscosity;

④ Clean the dust on the hydraulic oil radiator in time.

04 Strengthen daily inspection and regular inspection of hydraulic system

Some major failures of the hydraulic system often have some small abnormalities beforehand, which can be detected early through daily maintenance and inspection, prevented early, and eliminated the fault early.

① Check the oil pump before starting. Check whether the oil tank is short of oil before starting, and add the oil to the specified amount. When the oil temperature is lower than 10 degrees, the hydraulic system should be operated for more than 20 minutes under no load.

② The start-up and check-up of the oil pump can be carried out by starting and stopping. Repeat several times to increase the oil temperature and the hydraulic device can operate flexibly before entering normal operation. At the same time, pay attention to the noise of the oil pump. If the noise is too large, check the cause and eliminate it before normal operation can be carried out.

③ Check the working process of the hydraulic system. When the system is stable, pay attention to the oil volume, oil temperature, pressure, noise, hydraulic cylinder, motor, reversing valve, relief valve, and pay attention to the oil leakage of the entire system. And vibration.

④ After the hydraulic system has been used for a period of time, if there is an abnormality, and it cannot be eliminated by external adjustment, it can be disassembled and cleaned or replaced. Please lower the header, grain unloading pipe, reel, etc. to the position before disassembling the hydraulic parts, otherwise it may drop suddenly and cause personal injury. Be very careful when repairing complicated hydraulic components. Non-professionals should not disassemble them by themselves.

Hanjiu Hydraulics, hydraulic expert by your side!