Skeleton oil seals, also known as radial shaft seals or lip seals, are crucial components used to prevent leakage of lubricants and protect mechanical systems from contaminants like dust, dirt, and moisture. These seals are widely used in industries like automotive, machinery, and manufacturing, and choosing the right oil seal is essential for optimal performance and longevity. Here's a detailed guide to help you choose the correct skeleton oil seal for your specific application.

htob supply professional and honest service.

1. Understand the Application Requirements

The first step in choosing a skeleton oil seal is to fully understand the specific application for which it will be used. Factors like operational speed, temperature, pressure, and the type of fluid being sealed are important considerations.

- Operating Conditions: Determine the environment in which the oil seal will operate. Consider exposure to extreme temperatures, the presence of chemicals, and whether it will be used indoors or outdoors.

- Fluid Type: Identify the type of fluid the seal will be in contact with. This could include oils, grease, or other types of lubricants. Ensure the seal material is compatible with the fluid.

- Pressure and Speed: Know the maximum operating pressure and rotational speed of the shaft. Some seals are designed to handle high-pressure environments, while others are suitable for low-pressure applications.

Rubber Skeleton Oil Seal

2. Select the Right Seal Material

Skeleton oil seals are available in various materials, each with specific properties that make them suitable for different applications. The choice of material is critical as it affects the seal's resistance to heat, chemicals, and wear.

- Nitrile Rubber (NBR): The most common material for oil seals, NBR offers excellent resistance to oil and abrasion. It is suitable for temperatures ranging from -40°C to +120°C and is ideal for general-purpose sealing in industrial and automotive applications.

- Fluorocarbon (Viton): Viton seals offer higher resistance to heat and chemicals, making them suitable for high-temperature applications (up to 200°C). They are also resistant to a broader range of chemicals and are ideal for use in environments with aggressive fluids.

- Silicone Rubber: Silicone seals offer good flexibility at both high and low temperatures, but they are not as resistant to oil as NBR or Viton. Silicone is often used in applications where temperature resistance is more important than oil resistance.

- Polyurethane (PU): Known for its exceptional wear and abrasion resistance, polyurethane is often used in applications where the seal is exposed to high levels of friction and stress.

- PTFE (Teflon): PTFE oil seals offer excellent chemical resistance and operate well in a wide temperature range. They are commonly used in applications involving aggressive fluids or extremely high temperatures.

Rubber Skeleton Oil Seal

3. Choose the Right Lip Design

The lip design of the oil seal plays a crucial role in how well it prevents leakage and withstands pressure. Skeleton oil seals are available in different lip designs to suit varying applications.

- Single Lip (SL): Single-lip oil seals are designed to prevent leakage from the inside of the system. These are commonly used in general sealing applications where there is low pressure and no external contaminants.

- Double Lip (DL): Double-lip oil seals have an additional lip that provides extra protection against external contaminants like dust and dirt. These seals are ideal for outdoor applications or where the system is exposed to debris.

- Triple Lip (TL): These seals are used in heavy-duty applications where both high pressure and exposure to contaminants are concerns. The additional lips provide a more secure seal and extended durability.

4. Consider Seal Dimensions

Getting the correct size is essential to ensure a proper fit and effective sealing. Skeleton oil seals are typically specified by their inner diameter (ID), outer diameter (OD), and thickness or width.

- Inner Diameter (ID): This is the diameter of the shaft on which the seal will be installed. Measure the shaft accurately to avoid leakage or seal damage.

- Outer Diameter (OD): This is the diameter of the bore or housing where the seal will be installed. The outer diameter should be slightly larger than the bore to create a tight fit.

- Width: The width of the oil seal should match the depth of the groove or housing where it will be seated. An incorrect width can lead to misalignment and inadequate sealing.

It's important to follow the manufacturer’s specifications for the proper size. Using calipers or other precise measuring tools can help ensure an accurate fit.

Rubber Skeleton Oil Seal

5. Check for Operating Temperature Range

The temperature range that the oil seal will be exposed to is another key factor. If the temperature exceeds the seal's capacity, it can lead to degradation, hardening, or softening of the seal material, leading to premature failure.

- Low Temperatures: For cold environments, choose materials like silicone that remain flexible even at low temperatures. NBR seals can handle cold temperatures but are not as effective in extreme cold.

- High Temperatures: For high-temperature applications, consider materials like Viton or PTFE that can withstand heat without losing their sealing properties.

Always ensure the material and design you select are capable of operating at the upper and lower limits of your application’s temperature range.

6. Verify Pressure Handling Capability

While most skeleton oil seals are designed for low-pressure applications, some seals are specifically designed to handle moderate to high pressure. If your application involves significant pressure levels, be sure to choose an oil seal that can withstand the force without failing.

- Low-Pressure Seals: For most general-purpose applications, standard skeleton oil seals can handle low pressures effectively.

- High-Pressure Seals: For higher-pressure environments, choose seals with reinforced lips or specialized designs that can handle the extra force.

7. Review Shaft Surface and Speed

The condition and speed of the shaft on which the oil seal will be mounted directly impact the seal’s performance. A worn or rough shaft surface can quickly damage the seal, leading to leakage.

- Shaft Surface: Ensure the shaft surface is smooth and free from grooves, scratches, or other imperfections that can compromise the seal. A polished shaft is ideal for maximizing the lifespan of the oil seal.

- Rotational Speed: Oil seals are designed to handle certain speeds. High-speed shafts require seals that can withstand the friction generated by rapid rotations without overheating or wearing out quickly.

8. Evaluate Dust and Contaminant Exposure

If your application is exposed to harsh environmental conditions, dust, or debris, consider using double-lip or triple-lip skeleton oil seals. The extra lips provide additional protection, preventing contaminants from entering the system and compromising the lubrication.

For heavy-duty applications, seals with dust flingers or wipers may also be an option to keep contaminants at bay.

9. Look for Additional Features

Some skeleton oil seals come with extra features designed to enhance performance and durability, especially in demanding applications. These include:

- Spring-Loaded Seals: Some seals feature a spring that helps maintain a tight fit around the shaft, ensuring consistent pressure and preventing leaks, even as the seal wears down over time.

- Labyrinth Seals: These seals have a unique design that provides extra resistance to contaminants, making them ideal for applications involving extreme dirt or dust exposure.

10. Consider the Cost and Availability

Finally, when choosing a skeleton oil seal, consider both the cost and the availability of spare parts. While it’s important not to compromise on quality, balance your budget with the specific needs of your application. Additionally, ensure that replacement seals are readily available for maintenance purposes.

Conclusion

Choosing the right skeleton oil seal involves understanding your application’s specific requirements, including the environment, shaft speed, pressure, and type of fluid being sealed. Consider the material, lip design, and seal size carefully, and ensure that the seal you select is suitable for the operating conditions. A high-quality, well-chosen skeleton oil seal will ensure efficient operation, extend the lifespan of your machinery, and reduce downtime due to leaks or failures.

Find premium O-rings in all sizes and materials. Perfect for industrial sealing. High-quality Seals for various industries.

Featured content:
The Benefits of Using carbide ion formula
How much CO2 is emitted by manufacturing batteries? | MIT Climate ...
The Ultimate Buyer's Guide for Purchasing BOPP Tape Coating Machine

Are you interested in learning more about NBR O Ring? Contact us today to secure an expert consultation!

5 Steps To Choose The Right O-Ring

O-rings are robust sealing solutions for nearly endless applications in every industry. They will only work well, though, if you choose the right o-ring from the start. If you use the wrong material, profile, or size, your o-ring’s integrity will inevitably suffer and, ultimately, fail.

The good news is that you have the resources to make the right choice for your team right here. There are essentially five steps to choose the correct o-ring for your application. Barring unique application challenges, you should have the information to make the right decision for your seal after reading through these resources.

If you have any questions or unique considerations, our team is happy to help you find a solution quickly.

To determine if that step is necessary, let’s walk through the five steps to choosing the right o-ring for your application.

1. Identify Your Application’s Challenges

Before you can do anything else, you need to identify exactly what challenges your o-ring will face. We consider the following:

• Chemical exposure
• Ozone exposure
• Operating high temperatures
• Operating low temperatures
• High pressure
• Rapid decompression
• Static application
• Dynamic application
• Weather exposure
• Steam or hot amines

You should also be aware of any regulatory requirements of your application, such as USDA 3A, USP CL VI, or FDA CFR 21. 

Once you have the list of challenges your application will face and relevant regulations, you can get into the meat of choosing your o-ring.

2. Choose Your O-Ring’s Material(s)

One of the most important parts of choosing an o-ring is identifying the right material. A few popular options include FFKM, PTFE, EPDM, and NBR. 

FFKM

FFKM overcomes:

• Chemical exposure
• Ozone exposure
• Operating high temperatures
• Operating low temperatures
• High pressure
• Rapid decompression
• Static application
• Dynamic application
• Weather exposure
• Steam or hot amines

FFKM is best suited for high- or low-operating temperature applications and applications with aggressive solvents, chemicals, or media that would cause other materials to fail. It is used in almost every industry, particularly oil and gas, medical and pharmaceutical applications, and semiconductors.

PTFE

PTFE overcomes:

• Chemical exposure
• Ozone exposure
• Operating high temperatures
• Operating low temperatures
• Rapid decompression
• Static application
• Weather exposure
• Steam or hot amines

PTFE is best suited for applications that do not need a high compression set but also excellent chemical and temperature resistance. These include medical devices, coatings, and pest control. It also works well in ultra-low temperatures, like aerospace and automotive manufacturing.

EPDM

EPDM overcomes:

• Ozone exposure
• Operating high temperatures
• Operating low temperatures
• High pressure
• Rapid decompression
• Static application
• Dynamic application
• Weather exposure
• Steam or hot amines

EPDM is best suited for weatherproofing because it can withstand extreme elements. It is frequently found in roofing, windows, doors, cell towers, and other outdoor applications. It also works well with applications that use steam, automotive brake fluid, vibration dampeners, and isolators. 

NBR

NBR overcomes:

• Chemical exposure
• Operating low temperatures
• High pressure
• Rapid decompression
• Static application
• Dynamic application

NBR is universally used in basic sealing applications because it is low-cost and offers comprehensive benefits and physical properties. We see it often in automotive, water treatment and filtration, and pool and spa applications.

NBR can be formulated to excel in harsh environments, including aerospace and other low-temperature applications. 

Curious About Chemical Compatibility?

Use our comprehensive chemical compatibility guide to ensure the material that best meets your needs will also be compatible with the chemicals you use. The guide also includes a cost gauge to help you choose an option in your budget early on.

3. Choose Your O-Ring’s Profile

There are a few common profiles for an o-ring, but there are numerous solutions for a variety of challenges your seal might face. This knowledge is important, but we always have experts ready to help you choose the right material, profile, and size for your seal to ensure success.

With that being said, let’s lay out some profile basics!

O-Ring

First and foremost, there is the tried and true o-ring. O-rings are incredibly versatile and offer a wide range of solutions for almost any application and industry. These sealing solutions can also be paired with complementary fittings that help them function better in your application.

Pros

• O-rings are incredibly versatile. They are very customizable and come in various materials, colors, sizes, etc.
• They are one of the most common sealing solutions, making them readily available in a range of standard sizes, materials, and customization options.
• Because they are so widely available, o-rings are often cost-effective.
• If you are using o-rings in large quantities, you can purchase o-ring cord, which can be used to splice and vulcanize custom o-rings on-site.

Cons

• O-rings can sometimes be problematic in dynamic applications (twisting, rolling, etc.).
• They have limited high-pressure resistance. Thus, backup rings may be needed depending on your application pressure conditions.

While o-rings are often a solution, they might not be the best solution for your application.

X-Ring (or Quad-Rings®)

X-rings (or quad-rings®) are similar to o-rings, but their cross-section forms an X with four contact points. These are an alternative to o-rings and are recommended for low-speed reciprocating or oscillatory motions that are twisting, rolling, or bunching. 

Pros

• X-rings provide less friction than o-rings.
• They offer four points of contact when sealing.
• They are interchangeable with o-ring sizes and gland designs, making them an easy substitute. 
• These o-ring alternatives are available in the same standard sizes and custom sizes as o-rings, while being readily available in USA AS568 standard sized NBR Buna-N and FKM.

Cons

• X-rings are not recommended for pressures >500 psi.
• As they are more specialized, x-rings may not be available in all compounds.
• They are also a little more expensive than standard o-rings.

U-Cup Lip Seals

U-cup lip seals are in the same general shape as an o-ring, but the cross-section is a U. U-cups can function independently, but they also have the unique option of being “loaded.” A loaded u-cup has an o-ring or spring energizer nestled into its internal groove.

U-cups are designed for dynamic reciprocating applications up to PSI, but loaded u-cups can handle up to 5,000 PSI.

Pros

• U-cups have longer sealing life than o-rings because they experience lower levels of friction.
• These seals are also available in nonsymmetrical rod and piston configurations, which are common applications for u-cup seals.
• Polypaks® use an o-ring to provide sealing force at a low pressure.
• We can design custom lip seals for existing grooves that are not standard.

Cons

• Unfortunately, u-cups are more difficult to size than o- or x-rings.
• They are available in a limited array of materials and standard sizes.
• U-cup seals are a more expensive solution than other options.

Glyd Rings® 

Glyd Rings® combine the power of a Turcon-based slipper seal with an energizing o-ring to extend the life of an o-ring in dynamic, reciprocating applications. They use an interference fit that couples with the extra tightness of the o-ring to ensure a quality seal at lower pressure.

Pros

• Glyd Rings® are typically suitable for slow and fast reciprocating speeds running dry or lubricated.
• They can withstand pressures up to PSI in most applications.
• They operate at low friction with no stick-slip effect.
• Glyd Rings® are compatible with all o-ring materials.
• With a high wear resistance, they also offer minimal break-out force.

Cons

• Glyd Rings® cannot be stretched more than 5% during installation.
• They are not recommended for oscillating applications.

4. Size Your O-Ring

Sizing is by far the trickiest but most important part of choosing an o-ring. When we diagnose failed seals, an improperly sized o-ring is often the culprit.

To start, review gland design basics. Then, you will need to determine the way pressure works in your gland. Your operation will be one of the following:

1. Internal Pressure
2. Internal Vacuum
3. Dynamic Rod and Piston
4. Static Rod and Piston

Now, to determine your sizing, you will want to know the following gland measurements:

For Internal pressure:

• Inner Diameter
• Depth
• Width

For Internal Vacuum:

• Outer Diameter
• Depth
• Width

For Dynamic Rod and Piston:

• Outer Diameter Sealing Width
• D Diameter
• E Diameter
• F Diameter
• Inner Diameter Sealing Width
• II Diameter
• I Diameter
• G Diameter

For Static Rod and Piston:

• Outer Diameter Sealing Width
• D Diameter
• H Gap
• E Bore Diameter
• Inner Diameter Sealing Width
• H Gap
• G Tube Diameter
• F Gland Diameter

Now that you have your important measurements, you can use a comprehensive sizing chart to select the correct sized o-ring. The following links will take you to the corresponding sizing chart for your appropriate region:

USA O-Ring Sizing Chart

Common Metric O-Ring Sizing Chart

Japanese JIS O-Rings Sizing Chart

British BS O-Ring Sizing Chart

5. Choose Your Supplier

Last but certainly not least, you will need to choose your supplier. Your supplier should be your collaborative partner in consolidating and streamlining your sealing needs. To help you identify the exact questions you should be asking suppliers, we’ve included a comprehensive list in our Complete Guide To Choosing An O-Ring.

Get your free copy today!

If you want to learn more, please visit our website Motorcycle Oil Seal.

Related Pages