Oil Seal Buying Guide

Different types of oil seals

Do you want to keep your machine away from any unwanted leaks, but aren't sure which oil seal is right for your needs? This guide will provide you with everything you need to know in order to choose the right one for your application.

Oil seals, also known as rotary shaft seals, fluid seals or grease seals, play an important role in closing the gap between the moving and stationary elements of mechanical equipment.

Automotive Oil Seals

By preventing the leakage of lubricants, they protect critical parts of machinery from damage caused by leaks of various fluids. These Automotive Oil Seals are used from automotive engines to assembly machines to remain free from any harmful effects that can cause serious and costly damage to any of its critical components.

What is a rotary shaft seal?

Rotary shaft or oil seals are placed between moving and stationary mechanical parts to ensure that contaminants, moisture, corrosive materials and abrasives do not damage various components. They also prevent unwanted mixing of fluids, including water and oil, from combining within the machine.

How are oil seals made?

First, an elastomer, most commonly nitrile rubber, is vulcanized to a metal ring. This creates a stiffening effect, including a specialized metal tension spring directly behind the seal lip, which keeps the oil seal firmly attached to the moving parts.

Oil Seal Materials

There are many different materials used to make oil seals.

Leather Oil Seals - Leather oil seals, also known as L-shaped oil seals, are most commonly used for parts that are contaminated and poorly lubricated. Because leather oil seals are pre-lubricated and absorb fluids, they are able to provide sealing performance in situations where synthetic rubber cannot.

Synthetic Rubber Oil Seal- Styrene-butadiene rubber oil seals, or just SBR oil seals, are highly resistant to wear and damage, making them ideal seals for fast moving machinery. They can be used for outdoor components due to their heat aging properties that can withstand extreme temperatures. They are also considered to be more cost effective oil seals than natural rubber.

Nitrile Oil Seals - Nitrile oil seals is the common term for acrylonitrile-butadiene rubber seals and is a very good general purpose choice due to the flexibility of use on a wide variety of components. The high resistance to fats, hot water, gasoline, mineral oil, grease and animal oil makes them the most commonly used oil seal. They do not have a large temperature range, making them a poor choice for machines with drastic temperature changes.

Fluoroelastomer oil seals - Fluoroelastomers are synthetic rubber and fluoropolymer elastomers used to make oil seals that offer resistance in both high temperature and low compression permanent deformation components. They also have high chemical and wear resistance, so they can be used in components that frequently interact with petroleum and solvents.

Polyacrylate oil seals - Mostly selected for automotive and transmission use, polyacrylate oil seals withstand fuel, oil, ozone, sunlight and weather when in use. They are the perfect choice due to the exposure of the car to all these different fluids and elements. However, they should not be used at low temperatures as their flexibility is diminished at low temperatures.

Silicone seals - Designed to absorb lubricants to reduce wear and friction, silicone rotary shafts also have high thermal resistance and a large temperature range. However, they do not handle wear well or interact with oxidized oils.

PTFE Oil Seals - A relatively new and exciting type of oil seal, the use of PTFE means they can withstand dry or unlubricated operation. With a huge thermal range of -130ºC to +200ºC and strong chemical resistance, they are considered to be the future of rotary shaft seals.

How to choose the right oil seal?

When selecting an oil seal for your next project, there are several key factors to consider to ensure protection from immediate and long-term damage to machinery.

Pressure - Many oil seals can only withstand low pressure applications, so it is critical to understand the permanent deformation of the component in compression.

Temperature - Just like pressure, it is important to know the operating temperature of the oil seal so that you can select one that can withstand high or low temperatures. PTFE has the widest temperature range, making it ideal for machines used in extreme weather or components.

Shaft speed - Considering the speed the shaft will be moving, runout, bearing housing bore and the type of oil being sealed is critical to ensure that you select an oil seal that will not be affected by wear or spiral deformation.

Fluid type - Various oil seals can withstand interaction with oil, fuel, grease, water, etc. Knowing what type of fluid the rotary shaft seal will be in constant contact with will ensure the longevity of the seal and surrounding components.

Amount of lubricant - Seals always perform best when lubricated, but in some machines are more likely to dry out. For these cases, it will be beneficial to choose leather or PTFE seals, as both have less lubricity than other seals.

We hope you find the above sharing helpful, plus the company also has Kdik Combi Oil Seal available, contact us today to ensure you have selected the right rotary shaft seal to protect your components and bring long and healthy life to all your machines!