The sealing elements? mounting socket must be in a proper dimension to prevent damage of the sealing element during assembly, to ensure comfortable assembly and static sealing.
The socket to which the sealing element will be mounted should be designed as Figure 3 indicates and in the dimensions specified in Table 3.
The tolerance of the slot’ inner diameter should not be greater than the tolerance range of H8 (ISO 286-2)to ensure a proper static seal.
In order to provide a sealing element installation without damage, the surface roughness of the slot must be at the values defined in Table 4. Even a lower value is used in non-metal sealing elements.
There should be no deep scratches and metal burrs on the slot surface in order to ensure no damage nor sealing in element mounting.
The shaft on which the sealing element will be mounted should be at the appropriate dimensions and surface roughness values, which will prevent damage to the sealing element during assembly, ensure comfortable installation, and provide the most suitable working surface to the sealing element during the usage period.
In order to have an install without any damage, the end of the shaft should be bevel or radius between 1.8 and 3 mm as defined in Figure 4 and in the dimensions in Table 5.
The outer diameter tolerance of the shaft should not be greater than the h11 (ISO 286-2)tolerance range to ensure proper dynamic sealing.
In order to have a long working life of the sealing element and to form a thin film layer that provides dynamic sealing, the roughness values of the surface on which the sealing elements will operate must be in the values defined in Table 6. While the life of the oil seal is shortened on rough surfaces that are less than the specified values, the sealing can not be ensured since the thin oil film layer under the lip is not formed on the surfaces with less roughness.
In order to have a long life of the sealing element, the surface it will work on; must be free from dirt and rust. Hard chrome plated or stony surfaces are the most suitable work surfaces for sealing elements. If it is inevitable to have machining marks on the surfaces on which rotary shaft seals works; hence, the direction of the marks should be towards the oil side according to the direction of rotation of the shaft. Sealing elements operating with reciprocating motion must not have any traces of processing.
To have high performance of the sealing element, the hardness of the shaft it operates must be minimum 45 HRC. In cases where hardening is not done, the shaft will be damaged during operation.
In cases of dynamic seals, the runout values of the shaft must be within the maximum IT8 tolerance range.
