After the fd50 forklift produced by our company works for a period of time, when the load of the working device drops, the hydraulic oil is often sprayed from the oil tank respirator, accompanied by the sound of steam spraying.
The hydraulic oil tank of this type of forklift is an open structure commonly used in the industry. The gas in the oil tank is connected with the atmosphere through the respirator. When the oil return pipe returns oil, the excess air in the oil tank is discharged through the respirator. It is preliminarily analyzed that the reason for fuel injection is the insufficient ventilation of respirator, but the problem still exists after removing the respirator and working for a period of time. Remove the oil filler cap for test. After working for a period of time, the hydraulic oil is directly ejected from the oil filler cap.
The original hydraulic oil tank structure of this forklift is shown in attached figure (a). The orifices of brake pump, steering gear, multi-way valve and gantry cylinder return pipe are arranged above the hydraulic oil level, and the orifices are facing the steel oil suction pipe. Field observation found that when the load of the working device drops, a large amount of oil returns to the oil quickly and sprays to the oil suction pipe at high speed after passing through the oil return pipe orifice, forming fierce splash. After the hydraulic oil temperature rises, a large number of oil droplets and oil mist will be generated in the oil tank, which will sharply increase the air pressure in the oil tank. These oil, oil droplets and oil mist are finally discharged quickly through the respirator. Due to the blocking effect of the filter screen, oil droplets and oil mist accumulate on the filter screen when passing through the respirator. Under the action of the pressure difference between the inside and outside of the oil tank, the hydraulic oil is ejected from the respirator at high speed.
Due to the above problems in the hydraulic oil tank, after research, we decided to rearrange the position of the oil return pipe on the hydraulic oil tank. The structure of the improved hydraulic oil tank is shown in the attached figure (b). The specific method is as follows: arrange the brake pump oil return pipe, steering gear oil return pipe and multi-way valve oil return pipe with frequent oil return below the hydraulic oil level, stagger the positions of the oil return port and the oil suction pipe, and increase the distance between these oil return ports and the respirator as much as possible.
After the above oil return pipes of this type of forklift are rearranged, the three oil return ports with frequent oil return are below the liquid level, so as to avoid oil droplets or oil mist caused by high-speed oil return hitting the oil suction pipe, and the oil injection phenomenon of the oil tank respirator disappears. In addition, it can also improve the service life of hydraulic components.
