Main oil cylinder of oil press

The utility model relates to a main oil cylinder of an oil press. The cylinder comprises a left end cover, a sealing piece, a dustproof ring, a piston rod, a piston, a limiting block, a right end cover and a cylinder barrel. The left end cover, the cylinder barrel and the right end cover are connected through a screw, a nut and a gasket. The piston is arranged in the cylinder barrel and is matchedwith the cylinder barrel; one end of the piston rod is connected with the piston through a limiting block; the other end penetrates through the left end cover; thin-wall cylinders extending out of the piston are arranged at the two ends of the piston. A plurality of U-shaped grooves are formed in the end face of the thin-wall type barrel to serve as first-stage buffering. The left end cover and the right end cover are each provided with a limiting oil port communicating with the interior of the cylinder barrel. The two limiting oil ports are connected with an electromagnetic valve through oilpipes, a travel plate is