How are O-rings marked for size?

O-ring is a common seal, widely used in a variety of mechanical equipment. In order to ensure that the O-ring can be installed and operated correctly, the dimension marking and identification are particularly important.


First, the inner diameter (ID) and outer diameter (OD) of the O-ring are the main parameters for dimension marking. The inside diameter determines the fit of the O-ring to the shaft or hole, while the outside diameter determines the position of the O-ring in the slot. Typically, the dimensions of the inside and outside diameters are expressed in millimeters (mm). For example, an O-ring with an inner diameter of 20mm can be represented by "20".


Secondly, section diameter (CS) is also an important parameter for dimension marking. Section diameter Indicates the cross section diameter of the O-ring, usually in millimeters. For example, an O-ring with a section diameter of 5mm can be represented by "5".


In practical use, the size of the O-ring is crucial for installation and operation. For example, the inner diameter of the O-ring mounted on the shaft shoulder can be smaller, so that the assembly is not easy to slide out after being tightened on the shaft. The inner diameter of the O-ring installed in the hole groove can be appropriately large, so that it is easy to rise on the outside diameter when assembling, and it is not easy to make up and crush.


In addition, the groove size of the O-ring is also one of the key dimensions. The groove size must ensure that the O-ring has sufficient precompression to provide a good sealing effect during operation. At the same time, the groove size should also ensure that the O-ring has enough expansion space in the other direction to adapt to the motion trajectory of the equipment.


In general, O-ring dimension marking includes parameters such as inner diameter, outer diameter and section diameter. In actual use, according to different application scenarios and needs, choosing the right size for design and installation is the key to ensure the normal operation of O-rings. At the same time, the correct groove size is also an important factor to ensure the sealing effect and durability of the O-ring.


If you have other questions, please visit the Forever Seals official website for consultation


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