There are various structural forms of hydraulic cylinders, and their classification methods are also diverse: according to the motion mode, they can be divided into linear reciprocating motion and rotary swinging motion; According to the hydraulic pressure, it can be divided into single acting and double acting types; According to the structural form, it can be divided into piston type, plunger type, multi-stage telescopic sleeve type, gear rack type, etc; According to the installation form, it can be divided into pull rods, earrings, feet, hinge shafts, etc; According to the pressure level, it can be divided into 16Mpa, 25Mpa, 31.5Mpa, etc.