How to analyze the hydraulic system fault of bending machine?

Observe whether there is air bubble in the compressor lubricating oil of the bending machine, if any, it is caused by the gas entering the system; if not, turn to 2). Carefully observe whether there are two kinds of bubbles in the compressor lubricating oil, which are layer upon layer of large bubbles on the surface, most of which are not found in the compressor lubricating oil; and the other kind is the small bubbles in the compressor lubricating oil.

The reasons for the first type of bending machine's steam admission are: the plastic hose of the hydraulic pump's oil inlet leaks; the seal of the three-way joint is damaged; the seal of the hydraulic pump's shaft frame is damaged (the former one has a high probability).

Solution: remove the oil inlet plastic hose; remove the tee joint seal; remove the hydraulic pump shaft frame seal. Finally, there is no noise in the system, the pressure is normal when the oil temperature is low, and the pressure decreases when the temperature increases.

The air inlet of the second type bending machine is blocked by the filter screen 1 or the plastic hose for oil removal is brittle.

Solution: remove or remove filter screen 1 or oil-resistant plastic hose (be sure to replace the corrosion-resistant plastic hose). If the compressor lubricating oil is dirty, try to remove the new oil of the same specification and model. Adjust the speed regulating valves 6 and 5 to increase the rated current load of the system. Touch the hydraulic pumps 2 and 3 by hand. If the temperature rises rapidly and the vibration is abnormal, the internal parts of the pump are damaged.

Secondly, there is no noise and pressure in the bending machine system. First, observe whether the remaining oil in the oil return port of the system is normal. If everything is normal, listen to 5 and 62 speed regulating valves to see if there is any noise of compressor lubricating oil circulation. If yes, identify which one is, it means that the speed regulating valve is found abnormal and only one is eliminated. If there is any abnormal residual oil in the return oil inlet, it means that the pump is damaged, repair or replace the pump.

The common faults of this universal bending machine are not easy to distinguish and solve with the basic method, which can be solved by enumerating according to sections: firstly, from the analysis of the hydraulic schematic diagram, the system is divided into three system tests (one for the control circuit of an oil cylinder), and the system test of the electro-hydraulic reversing valve 7 is caused by the contradiction between the supply and demand of the pump 2 and the pressure oil; The two system tests of the electro-hydraulic reversing valve 12 and 14 are conducted by the pump 3 with conflicting pressure oil supply and demand. The following two parts are discussed.