Working principle and structure diagram of large-bore servo cylinder

With the development of automatic control technology, pneumatic servo systems are more and more widely used in electric power, metallurgical mining, textile machinery and tobacco machinery. The cylinder diameter of the servo cylinder in the pneumatic servo system currently produced in my country is relatively small, generally no more than 100mm, and the cylinder output force is relatively small, which is far from being able to meet the needs of large machinery such as electric power, metallurgical mining, etc.





Large bore servo cylinder structure diagram


The servo cylinder consists of a pneumatic positioner and an ordinary cylinder. Figures 1 and 2 are respectively the working principle diagram of the large-bore servo cylinder and the structural schematic diagram of the reversing valve in the positioner.





Figure 1 Figure 2





Working principle of large bore servo cylinder


As shown in Figure 1 and Figure 2, when the signal pressure increases, the stainless steel bellows moves upward, causing the gap between the lever 1 and the nozzle F of the valve A to decrease, thereby increasing the pressure in the back pressure chamber of the nozzle. P: increases, the diaphragm assembly E moves downward, the exhaust valve core C closes and the output valve core B opens, and the compressed air enters the rear chamber of the air range;at the same time, the displacement of the bellows causes the lever 2 to connect with the valve B nozzle F The gap 5 between them increases, thereby reducing the pressure in the back pressure chamber of nozzle B, the diaphragm assembly moves upward, the exhaust valve core closes, and the compressed air is discharged from the front chamber of the cylinder, so the cylinder piston moves downward. Due to the downward movement of the cylinder piston, the deformation amount of the feedback spring increases, causing the gap s2 between the lever 2 and the nozzle F of the valve B to decrease, the back pressure P2 increases, and the diaphragm assembly E moves downward, causing the The exhaust valve core C that was originally opened has a tendency to close, and the closed output valve core B has a tendency to open, so that the compressed air discharged from the front chamber of the cylinder decreases until it closes.





At the same time, the increase in the deformation of the feedback spring causes the gap between the lever 1 and the nozzle F of the valve A to increase, the pressure in the back pressure chamber of the nozzle F decreases, and the diaphragm assembly E moves upward, causing the originally closed The exhaust valve core C gradually opens, and the originally opened output valve core B gradually closes, thereby reducing the compressed air entering the rear chamber of the cylinder until it closes. When the signal pressure increases to a certain value, △x1= △x2=const, the output spool and exhaust spool of valve A and valve B are closed, and the cylinder is in a specific position. When the signal pressure is reduced, the working principle is exactly the opposite of the above. When the input signal pressure decreases to a certain value, △x1= △x2=const, the output spool and exhaust spool of valve A and valve B are also closed, and the cylinder is also in a certain position.



To sum up, the cylinder input signal pressure has a corresponding relationship with the cylinder displacement, and has nothing to do with the input working pressure.







The above is an introduction to the working principle and structure diagram of the large-bore servo cylinder. If you want to know more relevant information, please log in to Sunway Pneumatic www.diancifa.cc.