Created on:2021-06-30 14:18

Common faults of tractor hydraulic system

Common faults of tractor hydraulic system

(1) There is air mixed in the hydraulic oil and bubbles overflow from the oil filler

When working, there is air in the hydraulic oil, which will emulsify the hydraulic oil. When lifting farm tools, it will be weak, shake and accelerate the wear of the hydraulic pump. The main reasons are as follows.

① There are cracks in the oil suction pipe, uneven joints, damaged sealing gasket and oil leakage. When working, air will be sucked from the leakage place and bubbles will be generated in the oil tank. The crack of oil pipe can be welded, and the sealing gasket can be replaced.

② The working edge of the self tightening oil seal of the gear shaft of the hydraulic pump is worn, the rubber elasticity is reduced, and the failure causes the air to be sucked in from then on, so the self tightening oil seal can be replaced.

③ Insufficient oil in the hydraulic system will cause a large vacuum in the oil pipe and air bubbles in the suction air, so hydraulic oil can be added.

(2) The joystick does not automatically return to the neutral position from the raise or drop position

① Hydraulic pump distributor and other parts have been worn, the return valve is not closed tightly, so that the oil pressure in the distributor can not reach the automatic return pressure. Check the oil supply pressure of the hydraulic pump. If the pressure is insufficient, adjust the automatic return pressure to 11mpa; If the parts are worn, they must be repaired or replaced with new ones.

② The oil return valve is not closed tightly, so that the normal working pressure can not be established in the hydraulic system. When the small hole of the oil return valve is blocked, there is no way out for the high-pressure oil, which forces the oil return valve to open and causes the handle not to return automatically. At this time, the fault can be eliminated by cleaning the small hole of the oil return valve.

③ If the spring of slide valve becomes soft or broken, the spring of booster valve and positioning spring are too tight, the positioning steel ball is stuck in the groove and the return mechanism fails, the handle can not return automatically. The Distributor shall be disassembled and inspected, the automatic return pressure of slide valve shall be adjusted, and various springs and positioning steel balls shall be replaced and adjusted when necessary.

④ The opening pressure of the safety valve is too low and the elasticity is insufficient. When the farm tools are lifted, the safety valve opens too early and the pressure is lower than the automatic return pressure of the slide valve. The opening pressure of the safety valve can be adjusted to 13Mpa or the safety valve can be replaced.

⑤ Too high oil temperature or too low oil level in the tank can also cause automatic return. The oil temperature is too high, the hydraulic oil is too thin, the leakage increases, there is not enough pressure, the handle automatically returns, so that the automatic return mechanism fails; If the oil level is too low and the working pressure of the hydraulic pump is insufficient, the automatic return pressure will be reduced, and the automatic return mechanism will not work. Just lower the oil temperature and add oil to the oil tank.

(3) High oil temperature in hydraulic system

① When the amount of oil in the oil tank is too small, air is inhaled, and the hydraulic pump works under the condition of oil shortage, and the temperature will quickly rise to above 100 ℃. Add hydraulic oil, overheating phenomenon will disappear automatically.

② When the high pressure oil flows through the oil return valve, the oil will rub sharply around the valve seat and generate high temperature. The fault lies in the positioning valve and buffer valve.

③ When the distributor control handle is stuck in the working position, it will cause the hydraulic oil temperature to rise sharply. At this time, the positioning steel ball is stuck in the groove, and the slide valve cannot move.

(4) The suspension cannot be lowered

When the hydraulic linkage is in the highest position, pull the control handle to the down position, but the hydraulic linkage cannot be down. The reasons are: 1. The main control valve is stuck; ② The piston of the hydraulic cylinder is scratched and stuck in the hydraulic cylinder.

During disassembly and inspection, whether the valve is stuck or the piston is stuck, it should be ground or cleaned, and it should move freely after reassembly.

(5) Farm tools shaking

Lifting shivering is usually called hydraulic nodding. The causes are as follows.

① There is oil leakage in the check valve assembly. The reasons are: a. the sealing ring is damaged; b. Wear or strain of one-way valve seat; c. The compression spring is broken; d. The check valve assembly is not screwed in place or loose. Check the check valve assembly and installation position carefully. If there are damaged or deformed parts, they should be repaired. If they cannot be repaired, they should be replaced.

② The piston sealing ring of hydraulic cylinder is damaged. Replace the sealing ring.

③ The seal ring of lowering speed regulating valve is damaged. Replace the sealing ring.

④ The wear of main control valve mating pair increases the clearance and internal leakage.

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