The piston rod is a connecting part supporting the piston to do work. Most of it is used in the actuator of cylinder and cylinder. It is a moving part with frequent movement and high technical requirement. Take hydraulic cylinder as an example, it consists of cylinder, piston rod (cylinder rod), piston and end cover. The quality of its processing directly affects the life and reliability of the whole product. Colin column, piston rod processing requirements are high, its surface roughness requirements for Ra 0.4 ~ 0.8um, coaxiality, wear resistance requirements are strict. The outer diameter tolerance of the guide section of the piston rod shall not be lower than E8 of GB180 1, the roundness tolerance of the guide section of the piston rod shall not be lower than grade 9 of GB1184, and the straightness tolerance of the outer diameter bus bar shall not be less than 0.1/1000. Although it is not desirable to bear radial force from the design point of view, the piston rod of the hydraulic cylinder inevitably bears a considerable part of the radial external force due to the limitation of the actual structure. For this reason, the length of the piston of the hydraulic cylinder must be appropriate, and generally take 0.7 to 1 times the outer diameter of the piston rod. In order to increase its guiding role and increase the surface area of the support, so as to reduce wear and improve the service life of the hydraulic cylinder. The tolerance of perpendicularity of the end face of the piston rod in contact with the piston should not be lower than the level 7 of GB1184; the screw thread of the piston rod should be of the level 6 of GB197; the surface roughness Ra of the guide section of the piston rod should not be less than O.4/1m; The quality of the hydraulic cylinder depends largely on the quality of the piston rod, so the piston should be processed with sufficient precision tolerance. Generally speaking, the error of piston outer diameter, inner hole roundness and cylindricity should not be more than half of its dimensional tolerance; the tolerance of piston rod outer diameter to inner hole and sealing groove should be within 0.02 mm. It is generally required that the tolerance of the end of the cylinder to the axis of the hydraulic cylinder should be less than 0.04mm/100mm.
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