The sealing effect is achieved by manufacturing a smaller inside diameter than the required shaft size, which preloads the sealing lip. A garter spring is often used to ensure a constant force on the shaft.
- Oil seals are typically made from materials like nitrile rubber (NBR), which offers excellent resistance to oils and fuels, or polyurethane, which provides superior wear resistance. The choice of material greatly influences the seal's performance and lifespan. The 40x52x7 oil seal, being a standard size, is widely used in automotive engines, gearboxes, pumps, and various industrial machinery where reliable oil containment is paramount.
- Importance of Oil Seal Dimensions
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If the seal is being fitted to original equipment you may have some influence over the shaft and housing bore finish, but if you are replacing a worn seal you still need to take into account the condition of these 2 essential parts. Check for sharp edges and burrs – particularly on the shaft and housing chamfers or you could ruin the seal before you start up. If the shaft is too worn consider using an M Barnwell Services Shaft Repair Kit.
The oil seals represent the most important type of dynamic sealing on rotating shafts. During the last years, we witnessed a great evolution in the technology, starting from their shape to the materials used nowadays.
Read More About Valve Oil Seal supplier Xingtai Huimao Trading Co.,Ltd. is a leading oil seal manufacturing expert with a professional design and manufacturing team to provide high-quality oil seal products for all industrial and automotive applications. For more than 40 years, we have continuously improved our technology to meet the needs of various industries, and produced oil seals that meet customer needs. We work with customers to provide high-quality and fast service as well as customized requirements. Whether it is new product development or OEM oil seals, or looking for replacement parts or wear parts, our expert team can recommend suitable oil seals for your application.
Oil seals, also known as rotary shaft seals or lip seals, are a specific type of gasket designed to prevent the leakage of oil or other fluids in rotating shafts.

Almost every lip seal is constructed to have a flexible inner part that creates a dynamic seal on the moving shaft, as well as a hard outer casing that statically matches the machine-end cover. The flexible part is made from different grades of rubber, while the hard part is made of light-gauge metal or strong plastic.
Nitrile (NBR) Oil Seals
