1) master the original data and design basis, mainly including: the purpose and working condition of the main engine; Structural characteristics, load state, stroke size and action requirements of the working mechanism; Selected by hydraulic system

Working pressure and flow; The actual situation of materials, accessories and processing technology; Relevant national standards and technical specifications, etc.

2) According to the action requirements of the main engine, select the type and structure of hydraulic cylinder.

3) According to the external load acting on the hydraulic cylinder, such as gravity, friction force of external mechanism movement, inertia force and working load, determine the load change law of the hydraulic cylinder in each stroke stage and the power value that must be provided.

4) Determine the diameters of the piston and piston rod according to the working load of the hydraulic cylinder and the selected working oil pressure.

5) Determine the flow rate of the hydraulic pump according to the moving speed of the hydraulic cylinder and the diameters of the piston and piston rod.

6) Select the cylinder material and calculate the outer diameter.

7) Select the structural form of the cylinder head and calculate the connection strength between the cylinder head and the cylinder barrel.

8) according to the working stroke requirements, determine the maximum working length L of the hydraulic cylinder, usually L >；; =D, where d is the diameter of the piston rod. Because the piston rod is slender, the longitudinal bending strength should be checked and the hydraulic cylinder should be stable.