The piston rod is the connecting part which supports the piston to do work. Most of it is used in the moving parts of oil cylinder and air cylinder. It is a moving part with frequent movement and high technical requirements. Taking hydraulic cylinder as an example, it is composed of cylinder barrel, piston rod (cylinder rod), piston and end cover. The processing quality of inner tube mould directly affects the life and reliability of the whole product. The processing requirements of piston rod are high, the surface roughness is required to be ra0.4-0.8 μ m, and the coaxiality and wear resistance are strictly required. The basic feature of the cylinder rod is the processing of the slender shaft, which is difficult to process and has been bothering the processing personnel.

The function of the piston rod is to connect the piston and crosshead, transmit the force acting on the piston and drive the piston to move.

Basic requirements for piston rod:

(1) sufficient strength, rigidity and stability;

(2) good wear resistance and high machining accuracy and surface roughness requirements;

(3) the influence of stress concentration should be minimized in structure;

(4) ensure reliable connection and prevent looseness;

(5) the structure of piston rod shall be designed to facilitate the disassembly and assembly of piston.

The piston rod is processed by rolling, so as to improve the corrosion resistance of the surface, and delay the generation or expansion of fatigue cracks, so as to improve the fatigue strength of the cylinder rod Through rolling forming, a cold work hardening layer is formed on the rolling surface, which reduces the elastic and plastic deformation of the contact surface of the grinding pair, thus improving the wear resistance of the cylinder rod surface and avoiding the burn caused by grinding. After rolling, the decrease of surface roughness can improve the matching property. At the same time, it reduces the friction damage to the seal ring or seal when the cylinder rod piston moves, and improves the overall service life of the cylinder Rolling process is a high efficient and high quality process measure.