Radial Shaft Seal Lubrication Guide

Lubricants are used to reduce wear of dynamic mechanical components. Radial shaft seals keep these lubricants contained in a cavity or sump.

Referring to the Hydrodynamic Effect, a radial shaft seal rides on a film of fluid when rotating. This lubricant film is the primary reason the lip does not harden due to excessive heat. The dissipation properties of the lubricant are important and can impact the life of a radial shaft seal.

The seal lip and the lubricant must be chemically compatible to prevent elastomer degradation. With high demands being placed on the lubricants, additives are used to improve performance of lubrication. Unfortunately, these additives may have a negative affect on the sealing element. The affect of a compatibility problem is often seen when the seal lip has experienced hardening without signs of heat or the lip is excessively soft from normal use. A complete list of the additives in the lubricant are essential for a thorough analysis. Table 1 shows a list of the different types of additives that may affect material selection (See Fluid Compatibility, page). If lubricant additives are unknown, a Material Safety Data Sheet (MSDS) can be obtained, listing each additive.

Common Additives used in Lubricants:

All About Oil Seals

All About Oil Seals

 Oil seals go by many names, such as shaft seals, dirt seals, grease seals, lip seals, and many other variations of these. They are essentially simple devices used in rotary shaft equipment to prevent lubricant from escaping and for excluding contaminants such as dust, dirt and water. An oil seal’s most important function, however, is that it protects every type of ball, sleeve and roller bearing in the rotating shafts. The seals also prevent the integration of two different fluids that shouldn’t mix, such as oil and water.

How do oil seals work?

The basic principle of an oil seal is fairly straightforward. It is installed adjacent to the bearing, with the flexible lip against the rotating shaft and the casing pressed into the housing to hold the seal in place. It’s important that the sealing lip is lubricated to prevent it from overheating as a result of any generated friction. It’s also crucial to understand which type of seal is appropriate for your particular machinery. Before selecting your seal, consider the environment, temperature, pressure and shaft speed of your machine, as well as the type of medium the seal will come into contact with during operation. These considerations will all determine the size, colour, and type of lip material or sealing element to choose, and whether it can be sealed in or sealed out.

What material are oil seals made from?

Oil seals are made from multiple compounds and materials. Some of the oldest, still in use today, are leather and felt compounds. The trend in mass production, however, has seen a move towards synthetic rubber or elastomers. Nitrile is by far the most popular material but developments in PTFE have created a surge of interest in buyers needing seals for high-speed shaft rotation applications. Viton is taking over from the polyacrylic and silicone, as it works better in high-temperature applications and has a high-resistance to abrasion and harmful chemicals.

There are various sizes of industrial and ordinary oil seals, ranging from 0 to 33cm (13in). These varieties are also designed for different temperatures. As long as your seal matches the original equipment it’s intended for, you can be sure your machine will perform at its best. For further guidance and information regarding oil seals, don’t hesitate to contact our knowledgeable team. We are always available to assist you with your bearing, seal and gasket needs.

Everything you need to know about

Shaft seals, dirt seals, grease seals, lip seals, and many other names are only a few of the many names given to oil seals. They are simple components used in rotary shaft machinery to keep oil from leaking and impurities like dust, dirt, and water out. However, an oil seal’s most crucial role is to safeguard all ball, sleeve, and roller bearing types found in rotating shafts. Additionally, the seals stop blending two fluids that shouldn’t mix, such as water and oil.

What are oil seals?

A mechanical tool called an oil seal keeps lubricant from leaking out of the machine. It accomplishes its goal by sealing the equipment’s moving and stationary parts. Additionally, it prevents impurities from getting inside the machine and shortens its lifespan, an important role it completes.

Numerous oil seals exist, including PTFE lip oil seals, rubber fabric oil seals, and rotating V-seals.

An oil seal kit is a set of oil seals with the necessary dimensions and desired characteristics. An oil seal kit is more cost-effective and advantageous than buying individual oil seals.

Types of oil seal NBC offer 

Oil or other seals can be used for grease and oil seals. A flexible lip, radial lip, or rotating shaft seal are different names for an oil seal. Single lip, double lip, triple lip, and four or more lips are frequent configurations.

Double dust lip seal

A seal with a garter spring design is the Double Dust Lip (DDL) seal. It has two dust lips, as the name would imply, plus a fluid lip with a garter spring to keep the lip firmly attached to the wear ring. Given the ongoing evolution of bearing seal designs, this seal would be considered a starting seal. For more than 50 years, this design has been the workhorse of the freight business; it still is in some regions. NBC Brenco Bearing Seal performs the fundamental task of keeping contaminants and grease out. Because of the garter spring, this seal would add the most torque and temperature to the bearing.

Efficiency plus bearing seals

Due to eliminating the fluid lip using poly inserts and rotors, the Efficiency Plus (EP) seal has a reduced torque value of fewer than 15 in-lbs. Although it features a triple dust lip rather than a double dust lip, the dust lip is still a molded component of the design. A labyrinth-like insert and rotor interlock each other to replace the fluid lip. NBC Brenco labyrinth provides excellent grease while lowering the torque required to rotate the seal.

Other types of oil seal and grease seals include:

Single lip oil seal

Metal cased

All rubber or polymers

Internal orientation

External orientation

Axial orientation

Spring-energized

Purpose of oil seal

To serve as a physical barrier that keeps the lubricant in the designated area.

To stop the lubricating oil from leaking outside despite high oil pressure.

Act as a barrier to keep debris, contaminants, and other outside elements out of the system containing the lubricating oil.

Why is bearing a seal important?

Why are sealed bearings favored over the unsealed alternative? Why ought sealed ball bearings be preferred to unsealed ones? What advantages can sealed ball bearings offer?

Worry-free lubrication

No contact

Self-contained

What are bearing isolators?

Dynamic seals called bearing isolators are used to shield bearings from external impurities. They are revolving (rotor) and stationary (stator) elements. O-rings or strong seals are used in some bearing isolators, while they are constructed like labyrinths in others.

Different types of bearing seals

For many bearings, a good bearing seal is essential. Bearing seals perform a dual function by keeping lubricants from leaking out while preventing impurities from entering your parts. Both procedures can help your bearings last longer, but choosing the proper seals for your components is critical. Different types of bearing seals include:

Contact seals

No-contact seals

Labyrinth seals

Pick the proper seal for your bearing with the NBC bearing

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Several variables, including maximum temperatures, required lubricants, available space, and more, may influence your choice of bearing seal. Each factor can affect the type of bearing best for your application, the amount of material required, and other factors.

Although the choice of seals is crucial to the effectiveness of your bearings, you don’t have to make that choice alone. Our experts at NBC bearings can collaborate with you to identify the bearings and bearing seals that provide the best, most affordable solution for your application, environment, and finished product.