Common faults and maintenance methods of manual forklift liquid cylinder

1. Internal leakage in the hydraulic cylinder of manual forklift

When a manual forklift hydraulic cylinder has an internal leakage failure, the hydraulic oil of the manual forklift is directly flowing back to the fuel tank, which cannot complete the operation, causing the manual forklift hydraulic cylinder failure. The reasons and exclusion methods of internal leakage are as follows:

(1) The wear gap between the valve stem and the valve body is too large

There are multiple grooves on the valve stem and valve body of the manual forklift. The cooperation of the slot and the oil duct can be connected or cut off the oil circuit to change the working method. A normal distribution valve, the gap between the valve stem and the valve body is very small, and there is almost no oil leakage, so the drop or tilt of the hydraulic cylinder is small and will not affect the work. However, when the wear gap is too large, the hydraulic oil will cause the oil in the fuel channel to connect to the fuel -return channel or overflowing oil channel under the pressure of the oil pump operation, and automatically return to the fuel tank.

The main reason is that long -term use of the distribution valve or non -clean oil will accelerate the wear of the valve stem and the valve body, destroy the cover of the cover, lead to oil leakage. During the repair, if the valve stem is worn lightly, the valve stem can be polished chrome; if the valve stem is severely worn, it needs to be replaced.

(2) Oil leakage between valve body

Because the working oil channel, the fuel -return and the fuel -spill channel runs through the three separate valves, the sealing requirements between the valve body are very high. After installing O -shaped circles between the valve body and the valve body, the valve body is fixed with bolts to achieve the purpose of sealing. If the fixed torque of the bolt is different, the valve body may be distorted. The sealing ring fails, leading to internal leakage;

If the valve body is damaged during installation or the O -shaped circle aging and damage, in the action of oil pressure, internal leakage is also prone to occur between the valve body. During the maintenance process, if the valve body is damaged, the valve body is grinded, the O -shaped circle is replaced, and the bolt is tightened according to order and torque requirements.

2. Manual forklift safety valve spring and hydraulic cylinder steel ball failure

The manual forklift hydraulic cylinder safety valve is used to regulate the work pressure of the lifting system to prevent the components of the hydraulic system from being damaged to the limit position or other reasons due to overloaded hydraulic cylinder piston. The safety valve mainly achieves the purpose of opening and closing the position of the spring force on the steel ball.

When the oil pressure reaches the required value, the spring press the steel ball under the effect of its pre -tightening force, and the safety valve is closed. If the safety valve spring and steel ball fails, the hydraulic oil will force the steel ball to leave the valve position, flowing into the oil spill channel under the pressure below the system, causing internal leakage and failure of the system. You need to replace the spring and steel balls during repair, and then adjust the spring pressure to the tonnage with adjustment screws.

3. The oil cylinder valve stem and valve body cannot be reset

The return spring of the valve stem is installed at the lower end of the valve stem. Whether the valve stem is in the upper or lower position, the spring can be compressed. When there is no external force, due to the elasticity of the spring, the valve stem will quickly return to the original position. If the valve stem cannot be reset and the groove is connected to the oil duct, internal leakage occurs.

Reason 1: Due to the deformation or damage of the valve recovery spring, the spring force is reduced, and the valve stem cannot return to the original position. You need to replace the spring when repairing;

Reason 2: The uncleanness between the valve body and the valve stem will have a large resistance, which makes it difficult for the valve stem to reset. During the maintenance period, the interior of the multi -road replacement valve needs to be replaced.