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What Are Oil Seals and Their Common Types?

Oil seals are devices that maintain the integrity and efficiency of various machinery and equipment. Their main role is to prevent the leakage of lubricants and fluids while also protecting against the intrusion of harmful contaminants. Known as rotary shaft seals or lip seals in numerous settings, the purpose of oil seals is to seal the gaps between moving and stationary components in machinery. As such, they are primarily designed to retain lubricants and prevent the escape of fluids, such as oil or grease, while keeping out dirt, dust, and moisture.

In industrial applications, the efficiency and reliability of machinery primarily depends on the proper functioning of oil seals. These seals not only help to keep components properly lubricated, but they also protect them from premature wear and damage caused by friction and contamination. By preventing leakage and minimizing the entry of contaminants, oil seals significantly extend the lifespan of critical components, thereby reducing maintenance costs and downtime.

Common Types of Oil Seals

To meet the needs of various industries, oil seals are available in a wide range of types, many of which we will outline in this section.

  • Radial Oil Seals

Serving as the most commonly used type of oil seal, a radial oil seal consists of an outer metal casing, an inner sealing lip made of rubber or elastomer materials, and a tension spring that provides radial force to maintain contact between the sealing lip and shaft surface. Radial oil seals are suitable for rotary shafts and can effectively seal against both fluid leakage and contaminants.

  • Cassette Seals

Cassette seals are a more advanced type of oil seal, often finding employment in demanding applications. These seals consist of multiple sealing lips and are designed to provide superior protection against heavy contamination and extreme operating conditions. Moreover, they offer higher resistance to pressure variations, temperature variations, and misalignment, making them ideal for use in heavy-duty machinery.

  • V-Seals

V-rings, also known as axial or V-seals, are versatile oil seals designed to close off rotating shafts. They feature an elastomeric, V-shaped ring that acts as a lip to prevent the ingress of contaminants and retain lubricants. Moreover, they are easy to install, provide effective sealing for an array of shaft sizes, and are suitable for applications where space constraints or misalignment are a concern.

  • Rotary Shaft Seals

Rotary shaft seals, as their name suggests, are designed to seal rotating shafts in various industrial applications. They consist of an outer metal case, an inner sealing lip, and a garter spring that maintains the lip's contact with the shaft surface. Generally, these seals are highly versatile, cost-effective, and widely used in automotive, manufacturing, and processing industries.


By understanding the different types of oil seals available, anyone from industry professionals to DIY enthusiasts can make informed decisions when it comes to selecting the most suitable seal for their specific needs. It goes without saying that investing in high-quality oil seals can significantly improve equipment reliability, reduce maintenance costs, and enhance overall productivity in industrial settings. With this in mind, the inventory of sealing solutions at After Market Industrials cannot be beat. Check out the unrivaled inventory of industry-grade components on our database to gain access to thousands of listings from your favorite manufacturers. Get started today with the submission of an RFQ form and see how we can secure everything you require with time and cost savings!


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