Examples of the use of seals in hydraulic equipment

A certain CE7120 hydraulic profiling lathe, during the work, the profiling tool holder leads the knife down and turns the longitudinal feed to cut the knife, resulting in frequent knife punching and scrapping, and the machine tool cannot work normally. Inspection and maintenance: Check that all hydraulic control components are free of faults, and the maintenance work will enter the blind spot for a while. Disassemble and inspect the longitudinal oil cylinder of the tool holder, and find the piston oil seal“O”The outer circle of the seal ring has been ground flat, and it is found that the outer circle of the piston does not meet the requirements (because of the machine tool manufacturing), the diameter direction is smaller than the standard size of 0.8MM, and the gap between the piston and the cylinder block is large, which causes the two chambers of the longitudinal cylinder to communicate with each other. At the time of maintenance, a qualified piston was replaced and“O”Troubleshooting of the punching tool of the machine tool after forming the sealing ring. The reason is analyzed that at the moment when the profiling tool rest is brought down and in place, the tool rest as a whole is subjected to an impulse F.’, after the force is decomposed, there is a horizontal thrust F’1 acts on the piston rod of the longitudinal oil cylinder. At the same time, the solenoid valve 34E1-25B works, the rod cavity of the longitudinal oil cylinder is connected to the pressure oil, the rodless cavity is connected to the return oil circuit of the speed control valve, and the force F of the rod cavity of the piston is connected by Two parts are completed, one is F’1, the other is F1=A1P1, where A1 is the force area of ​​the rodless cavity, then F=F’1+F1. Under normal circumstances, the piston starts to move to the rodless cavity under the action of the force F. Due to the incompressibility of the hydraulic oil, the pressure of the hydraulic oil in the rodless cavity suddenly rises to form a back pressure on the piston, and the piston is balanced by the speed regulating valve. Set the speed to move the knife smoothly. The moment has %F’1, the pressure P2 in the longitudinal cylinder cavity will be greater than P1. In practice, the two cavities of the oil cylinder are channeled due to the gap. At the moment of P2>P1, the hydraulic oil has a tendency to flow from the rodless cavity in the high pressure area to the rod cavity in the low pressure area. Once the flow occurs, P2 decreases, P1 increases, and F1 increases. If it is too large, the force on the piston is out of balance, and the piston drives the tool holder to move quickly to the direction of the rodless cavity. After an instant, the horizontal thrust F acting on the piston of the longitudinal oil cylinder is due to the end of the downward movement of the profiling tool post.’1 disappears on its own, the rapid movement of the piston ends, the tool movement of the tool holder becomes stable, and the punching phenomenon ends. Company website: https://www.orksealing.com/