Oil Seal Types: Everything You Need to Know

There is more than one type of oil seal on the market today, and it can be tricky to know which one to use and when. This article has been compiled by our experts and will provide a more in-depth look at this topic and explain the differences and applications of various oil seal types, and how to know what size you need. Keep reading to know all there is to know about different types of oil seals.

WHAT IS AN OIL SEAL?

An oil seal, sometimes known as rotary shaft seals, grease seals, dirt seals, fluid seals or lip seals, is a mechanical component that both prevents lubricant leakage and the entry of contaminants into a shaft, bore or bearing. This prolongs the life span of whatever application it is a part of, leading to less down time due to breakages or repairs and continuous operation efficiency. Different types of oil seals are used across every industry, and in everything from adjustable seats in cars to industrial equipment and aeroplanes. Here at The Bearing Company we stock a wide range of both imperial and metric sized oil seal types, for virtually every eventuality.

TYPES OF OIL SEALS

Nitrile is the most commonly used material for oil seals due to its excellent resistance to oils, fuels and other chemicals, as well as its durability and flexibility across a wide temperature range. Also known as NBR (Nitrile Butadiene Rubber), nitrile offers strong wear resistance, good tensile strength and cost-effective manufacturing, making it ideal for a variety of industrial and automotive applications.

Another widely used material is Viton, a type of fluoroelastomer known for its superior heat and chemical resistance, which makes it suitable for high-temperature or particularly aggressive chemical environments.

Most types of oil seals are typically available in two main designs: metal-cased and rubber-cased. The following section will explore these designs in greater detail, highlighting their construction, advantages and their common applications.

RUBBER CASED OIL SEALS

Rubber cased oil seals types consist primarily of a durable elastomer body, often reinforced with a thin metal insert for added stability. They provide excellent flexibility, tight sealing and resistance to wear and contaminants. At The Bearing Company, our oil seals are made with high-quality rubber, ensuring reliable performance, long service life and effective protection for bearings across a wide range of industrial and automotive applications.

R21

This oil seal is rubber cased with a metal inner core and a single sealing lip. It is particularly well suited for applications where compensation for minor housing irregularities is required.

R23

An R23 oil seal is fully rubber encased with a metal inner core and a double sealing lip. Featuring both a primary and secondary wiper, it provides superior protection against contamination and ingress.

METAL CASED OIL SEALS

Metal cased oil seals feature a rigid outer steel shell that provides greater strength, dimensional accuracy and a secure press fit within the housing itself. Compared to rubber cased types of oil seals, they offer a greater level of structural stability and durability. These advantages make them ideal for high-speed, high-pressure or precisely machined applications

R1

This type of oil seal is metal cased and features a single rubber sealing lip, designed to provide a strong radial fit. It is commonly used where reliable sealing and structural stability are required.

R4

An R4 oil seal is also metal cased and includes a single rubber sealing lip that delivers increased rigidity. This design ensures a secure, consistent fit within the housing, even in demanding operating conditions.

R6

This oil seal type is metal cased and incorporates a rubber sealing lip alongside an additional wiper lip. The added wiper enhances protection against dirt, dust and contaminants in harsher environments.

FINDING THE RIGHT SIZE OIL SEAL

Once you have identified the correct oil seal type your next step is selecting the right size. This is an essential point for achieving an effective, long-lasting sealed unit. Oil seal sizing is determined by measuring the shaft diameter, housing bore diameter and seal width. These dimensions must be accurate to ensure a proper fit, prevent leakage and avoid premature wear during operation.

THE BENEFITS OF OIL SEALS

Different types of oil seals play a vital role in protecting all kinds of machinery by retaining lubricants and preventing the ingress of dirt, dust and moisture. By maintaining proper lubrication, they help reduce friction and wear on rotating components, extending the service life of bearings and shafts. Oil seals also support consistent performance by minimising leakage, which can otherwise lead to inefficiency, downtime and increased maintenance costs. Their use contributes to improved reliability, reduced equipment failure and safer operating conditions.

Available in a range of materials and designs, oil seal types can be selected to suit specific temperatures, speeds and environmental conditions. This makes them a highly versatile and cost-effective sealing solution for industrial, agricultural, aerospace, automotive and many more applications.

SHOP OIL SEALS AT THE BEARING COMPANY

This guide should have outlined key oil seal types, materials, designs and applications to help you choose the right solution. The Bearing Company stocks a wide range of high-quality oil seals for a whole variety of uses, with fast UK delivery, competitive pricing and expert support. Shop now for different types of oil seals and find the right seal today, by phoning us on 01527 809 620 or emailing us at sales@thebearingcompany.co.uk. You can also find gamma seals, pillow block seals, v ring seals, blanking seals and more.

With trusted brands, reliable availability nationwide and free delivery when you spend over £50, it is no surprise why we have been your trusted partner for bearings and seals for over 50 years.