How to choose the inner and outer diameters of O-rings of non-standard hydraulic cylinders

How to choose the inner and outer diameter of hydraulic cylinder O-ring?

        1. When the O-ring is used for the piston seal of the hydraulic cylinder, the inner diameter of the O-ring we choose should be smaller than or equal to the bottom diameter of the groove, in other words it should be slightly tighter, that is, the O-ring is stretched .

        2. When O-rings are used to seal the piston rod of hydraulic cylinders, the outer diameter of the O-rings selected should be larger than or equal to the bottom diameter of the groove.

        3. When the O-ring is used for axial sealing and is subject to internal pressure, the outer diameter of the O-ring of our hydraulic cylinder should be greater than or equal to the outer diameter of the groove at this moment, that is to say, it should expand slightly; when subjected to external pressure At this time, the inner diameter of the O-ring of the hydraulic cylinder should be smaller than or equal to the inner diameter of the groove, which means it should be slightly tighter.

        4. When the O-ring is used for rotating shaft sealing, the inner diameter of the O-ring should be larger than or equal to the diameter of the rotating shaft, that is to say, the inner diameter of the O-ring should be slightly looser than the diameter of the rotating shaft.