Oil Seal: Get To Know All The Details About This Component

Oil seal: get to know all the details about this component

 

Fundamental things and its importance 

 

An oil seal, also known as crankshaft retainer, is a small device, but essential to ensure the proper engine operation. It plays a key role in all moving parts of an engine, acting as a physical barrier. This mechanical seal fulfils the dual purpose of sealing a rotary shaft to maintain the necessary lubrication (avoiding leaks) and preventing other foreign matter from contaminating shafts and bearings in the rotary shaft equipment.

It is generally used in the union of two lubricated parts, so that it hermetically seals both sides. Therefore, it guarantees the proper engine operation and helps to maintain the vehicle’s distribution system in better condition.

 

 

 

Oil seal characteristics

 

Several variables must be considered when selecting oil seals. The physical dimensions and materials will vary depending on the environment of use. In addition, oil seals must remain lightweight, compact, and exhibit high self-lubrication performance.

Most oil seals consist of some basic elements that configure their structure, such as the sealing element, the metal case, and the spring:

 

 

 

Dust lip

: prevents particles from reaching the sealing lip.

Sealing lip

: guarantees dynamic and static sealing.

Metal case

: the metal case supports the rotary shaft seal, ensuring the structural stability.

Spring

: spiral shaped, ensures constant pressure and maintains the optimal force to the shaft.

 

 

 

Aspects to consider when selecting oil seals

 

Operating conditions such as the engine’s temperature, position, size, pressure and shaft speed largely determine which individual oil seal composition is most suitable for every individual application.

Some aspects to consider when selecting this component are:

Temperature:

The temperature within the oil seal environment is the main factor that dictates the composition of an oil seal. Generally, there is a range of set temperatures that are optimal for that material. If the operating environment is too cold, the seal may become brittle and, at high temperatures, the seal material may show increased elasticity and become leaky.

Pressure:

As the pressure increases, the radial load and the friction of the sealing lip increase in contact with the shaft. As with temperature, each oil seal has a recommended pressure for optimum performance. Excessive pressure causes the seals to wear more quickly and consequently have a shorter life.

Shaft Speed:

The speed at which an oil seal can operate effectively depends on the previously outlined conditions together with the design of the seal itself. Some designs allow for a range of maximum peripheral speeds and are therefore more suitable for larger shaft diameters. Speeds below and above the recommended range can cause friction and thus impact the sealing material.

 

 

 

Common causes of oil seal failure

 

Like any element of the engine, oil seals are subject to wear. Over time they can lead to possible leaks of lubricating liquid.

Among the most common causes of oil seal failure are:

Installation inaccuracies

, such as placing the seal in the wrong position in its housing or handling it incorrectly.

Improper

use of sealants

.

Imperfections on the shaft

(burr, corrosion, etc.), which will directly affect the service life of the oil seal.

Cracks or swelling

of the component due to extreme temperatures, causing premature deterioration of the oil seal material.

Other maintenance factors, such as

insufficient lubrication

inside the engine.

 

 

 

Oil leak: the most frequent failure of the oil seal

 

Finding oil spots under a parked vehicle can be both worrying and stressful for any vehicle owner. If the seal’s leak is small, oil may start to accumulate on the underside of the engine. But as the leak gets bigger, the oil leak will become visible in the front side of the engine.  

Wear and oil loss remains two of the most frequent signs of engine seal failure and, if not paid attention to, it can give rise to a breakdown in the vehicle’s system. Regular maintenance and routine oil changes minimize the issues associated with oil seals and potential oil loss. 

 

 

 

 

 

Dolz, your safety choice

 

Oil seals included in the Dolz timing chain kits are lightweight, high-precision seals with wear resistance and made from the highest quality materials.

It is recommended to replace all timing elements in a single operation, ensuring an optimal coupling of the components and thus avoiding premature aging and possible future engine failure.

At Dolz we put our almost 90 years of knowledge and experience at your service to provide you with an optimal replacement of your components.

Are you looking for the best solutions for the distribution of your vehicle?

Contact us to learn more about our full range of products!

 

 

 

Common Types of Oil Seal Materials

What is an oil seal? 

Seals are essential to protecting the bearings of any rotating shaft assembly -They prevent contaminants such as dirt, dust and water, while also preserving the system’s lubricant.

 

Choosing the right oil seal

Oil seals come in many different types and materials depending on their application. Determining the material is vital to ensuring your equipment is operating at its best performance. For example, your equipment may need to run at higher temperature applications, such as an engine seal for a jet engine, you may need to choose a specific material for your oil seals to run properly. In this article, we will explore the most popular and utilized materials in the industry, as well as touch on some of the more unique options out there.

 

Oil seal materials

 

Nitrile

The first material that we are going to look at is Nitrile Buna- N 70 or NBR for short. 

 

NBR is recommended for the majority of standard applications and is the most commonly used rubber (elastomer) material. This is because of Nitrile's compatibility with most environments as well as its relatively low cost. Generally nitrile is used for disposable non-latex gloves, footwear, automotive transmission belts, synthetic leather, hoses, o-rings, gaskets, oil seals, and more. 

 

The temperature range of nitrile is −35° to 120 °C (−30° to 250 °F). Due to this wide range, NBR seals can be used for gas oil, silicone oil, animal/vegetable oils and fat, hydraulic liquid as well as hot and cold water. In addition, NBR is oil resistant and has an excellent abrasion resistance, so for any application that demands shock absorbers, NBR is a perfect choice to go with. 

 

Some disadvantages of NBR are poor ozone, sunlight and weather resistance as well as limited high temperature and flame resistance. For higher temperature resistance, a much better material to use is Silicone. 

 

Silicone 

Silicone compounds or “VMQ” offers a wide range of traditional operating temperatures starting at -60°C to 200°C (-140°F to 392°F). 

In addition to its excellent temperature resistance, it is also resistant to ozone, light, and weather conditions. Silicone can be typically found in the food and medical industry as well as in hydraulics and pneumatics. It is often the preferred material for o-rings, moulded parts and flat seals but is also commonly used for electric insulators due to the material’s translucency and flexibility. 

 

Although extremely flexible, silicone does have some disadvantages. Many silicone compounds have poor tensile strength, tear resistance, and abrasion resistance. If you are looking for a material that offers a higher tensile strength, while still offering high temperature resistance, look no further than Viton®.

 

Viton® 

Viton®, a trademarked name of The Chemours Company, is a specific brand of synthetic rubber commonly used in o-rings, oil seals, gaskets, chemical resistant gloves, and other molded products. 

Due to having a higher density, Viton has the widest temperature range of -40°F to over 400°F (-40°C to over 240°C) making it a perfect choice for higher temperature applications. Viton® also has the largest range of chemical resistance, i.e., it is resistant to silicone oil and grease, mineral/vegetable oil and grease, aliphatic, aromatic, and chlorinated hydrocarbons, non-flammable hydraulic fuels as well methanol fuels, and more.
 

Although it does have a higher tensile strength and longer wear times than other materials, it is recommended to be used in dry-running applications sparingly or intermittently. 

 

While Viton offers a superior temperature and chemical range than other materials, it can be more expensive than the others as well. Let’s take a look at an alternative that is easier on the wallet, Polyacrylate. 

 

Polyacrylate is a great compromise between cost and quality. It has a high performing temperature and chemical range, but not to the extent of the range of Viton. The temperature ranges from 31°C to 148°C (-25°F to 300°F). Polyacrylate is primarily used in automotive transmissions and hoses but also found in shaft seals, gaskets and o-rings, due to offering a high resistance to hot oil and oxidation. While Polyacrylate is a great alternative to other high temperature resistant materials that are more expensive, it does have a poor water compatibility and cold flexibility. The best situation for Polyacrylate is an environment where heat and oil resistance but cost is the major issue. And while these 4 different materials cover a wide range of applications, there are even more materials out there designed for very specific niches in mind.

 

Summary

 

If you are looking for the highest temperature resistant oil seals, Perfluoelastomer can go up to 600°F. If you are more concerned for low temperature, Chloroprene can go all the way down to 40°F, which is why it is used most commonly for refrigeration. And if FDA applications or medical devices are your primary concern, Butyl , the all petroleum compound, will be your best choice. As you can see, when choosing the right material to work with, you must analyze several other key components to help choose the right one. 

 

Hopefully after reading this article, you have a better understanding of why choosing the right materials for oil seals is so important. Remember, if you have any questions about industrial oil seals and supplies, please contact us and we would be more than happy to help.

 

Definition from Valaq

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