What is the meaning of piston rod outer diameter tolerance and analysis of problems

The piston rod of the oil cylinder is 40, the cylinder diameter is 50, and the stroke of the oil cylinder is 1480?

Cylinder piston rod is 40, cylinder diameter is 50, cylinder stroke is 1480, then, in the piston rod material, should choose 40Cr, if it does not bear the lateral force, and, to quenching and tempering treatment. If it has to bear the lateral force, it can only be considered and selected separately.

Piston rod, its outer diameter tolerance is f7-f8, what does it mean?

If the tolerance of the outer diameter of the piston rod is f7-f8, then the tolerance of the outer diameter of the piston rod can be F7 or F8. Where f refers to the tolerance of the axis, that is, the position of the tolerance zone, and the number refers to the tolerance level. As for the deviation value, we should look up the table according to the diameter of the piston rod. Then, we can get accurate figures, which can also avoid mistakes.

In the oil cylinder, why do the piston rod and the cylinder barrel fit together? And, what is the cause of longitudinal scratches on the piston rod?

In the oil cylinder, the fit between the piston rod and cylinder barrel is mainly clearance fit, while the piston ring mainly plays a sealing role. As for the longitudinal scratches on the piston rod, they are caused by the particle impurities in the hydraulic oil of the cylinder. Moreover, it can be used to judge the quality of chromium plating on the surface of piston rod, and then judge whether it is related to the quality of chromium plating.