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Selection And Use Of O Ring Seals
Dec 21, 2017

The rational selection of seals plays an important role in the performance and service life of the hydraulic components. The author has long been engaged in some experiences accumulated in this work, the seal design principle, selection, pre sealing occasions in compression, groove size and assembly notes on O are described in detail, for reference.


The O ring has good sealing performance. The sealing pressure is in the range of 1.33 * 10-5Pa to 100MPa. Because of its advantages of simple structure, reliable performance, low price and easy selection, it is widely used in all kinds of static and dynamic sealing situations. This paper, based on the experience and experience of the author's years engaged in the design of hydraulic pneumatic components, focuses on the design, selection and related matters of O type ring.


1. Main points of design


Selection of 1.1, O type ring size and material hardness


1) the principle of size selection


(1) the selection principle of the cut diameter D2 of the O type ring. Figure 1 is the size diagram of the O type ring. In order to achieve the best sealing effect, the cut diameter D2 of the O ring should be as large as possible.

o seal ring.jpg

In the application of dynamic seal, considering the dimension tolerance factor, the larger diameter is recommended for the same inner diameter D1. In the application of static seal, it is more safe and reliable to choose the larger diameter than the smaller one.


(2) the selection principle of the inner diameter D1 of the O type ring. The selection principle of O type loop internal diameter D1 please refer to the relevant contents of the 1.3 and 1.9 in the article. The data shown in Table 1 is recommended below for reference when selecting the size of the O type ring.

o seal ring.jpg

2) the principle of material and hardness selection


The hardness of the O type ring material depends on the working pressure, the clearance value and the application (dynamic and static seal) and the surface processing quality of the sealed parts. For standardized applications, the hardness of the recommended material is Shaoer A70, while when the pressure is higher than 20MPa or the pulse pressure is applied, the hardness of the material needs to be improved accordingly.