Hydraulic cylinder is the hydraulic energy into mechanical energy, a straight line reciprocating motion (or swing movement) of the hydraulic actuators. It is a simple structure, reliable work. Use it to achieve the reciprocating motion, can be removed from deceleration devices, and there is no transmission gap, smooth motion, so in a variety of machines are widely used in hydraulic systems. Hydraulic cylinder output force and the effective area of the piston is proportional to the pressure on both sides; hydraulic cylinder is basically a cylinder and cylinder head, piston and piston rod, seals, cushioning device and exhaust composition.