O-Ring NBR 110x5.5 mm 70 Shore A - Nitrile Rubber Sealing Ring

O-ring NBR 110x5.5 mm 70 Shore A is an elastomeric sealing ring with a nominal inside diameter of 110 mm and a circular cross-section diameter of 5.5 mm. Manufactured from nitrile butadiene rubber (NBR) with a nominal hardness of 70 Shore A, it has a calculated nominal outside diameter of 121 mm. The O-ring is designed for properly engineered static sealing arrangements and selected dynamic applications, particularly those involving compatible mineral oils and lubricating greases.

Technical Specifications - O-Ring NBR 110x5.5 mm

The nominal outside diameter is calculated from the inside diameter and twice the cross-section diameter:

110 mm + 2 x 5.5 mm = 121 mm.

Exact dimensional tolerances, operating temperature limits, permissible pressure and chemical resistance depend on the specific NBR compound and manufacturer's specifications.

What Does O-Ring 110x5.5 NBR 70 Shore A Mean?

110 - Inside Diameter

The first value identifies the nominal inside diameter of the O-ring, which is 110 mm.

This dimension is essential when selecting the sealing ring for the shaft, housing or groove geometry.

5.5 - Cross-Section Diameter

The second value specifies the nominal circular cross-section diameter of 5.5 mm.

This dimension influences the required groove depth, sealing compression and available installation space.

NBR - Nitrile Butadiene Rubber

NBR is a synthetic elastomer widely used in industrial sealing applications.

It is commonly selected because of its resistance to many mineral-based oils, lubricating greases and compatible industrial fluids.

NBR is also commonly referred to as nitrile rubber or Buna-N.

70 Shore A - Elastomer Hardness

70 Shore A indicates the nominal hardness of the rubber compound on the Shore A scale.

This hardness is widely used in general-purpose sealing applications because it provides a balance between elasticity and mechanical resistance.

However, hardness alone does not determine permissible pressure or guarantee compatibility with every oil or chemical.

Construction and Operating Principle

An O-ring is a continuous elastomeric ring with a circular cross-section.

It does not contain a metal reinforcement, spring or additional sealing lip.

Its sealing action is based on controlled elastic deformation between mating surfaces.

When installed in a correctly designed groove, the O-ring is compressed to create contact pressure.

This pressure helps prevent the sealed medium from passing through the joint.

In pressurised applications, fluid pressure may further increase the contact pressure between the O-ring and the sealing surfaces.

Effective sealing depends on the correct groove geometry, surface finish, initial compression, dimensional tolerances, extrusion clearance and operating conditions.

Properties of NBR 70 Shore A

Resistance to Mineral Oils

Nitrile rubber is commonly used in applications involving mineral oils.

This makes NBR a widely selected material for machinery, hydraulic components and lubrication systems.

Actual resistance depends on the oil formulation, chemical additives, operating temperature and exposure duration.

Resistance to Lubricating Greases

NBR is compatible with many lubricating greases based on mineral oils.

However, compatibility should be confirmed for the actual grease formulation and operating conditions.

Elasticity and Compression

An O-ring with a nominal hardness of 70 Shore A can deform under installation compression.

This allows the elastomer to conform to the mating sealing surfaces.

Maintaining suitable elasticity is important for reliable sealing performance.

Mechanical Properties

Appropriately formulated NBR compounds can provide useful mechanical strength and wear resistance.

These characteristics depend on the specific rubber formulation and manufacturing process.

Material Limitations

Standard NBR generally has limited resistance to ozone, prolonged ultraviolet exposure and outdoor weathering.

It may also be unsuitable for certain solvents, aggressive chemicals and high-temperature applications.

Material compatibility must be evaluated for the actual medium and operating environment.

Static Sealing Applications

O-ring NBR 110x5.5 mm 70 Shore A can be used in properly designed static sealing arrangements.

Typical applications include:

• Machine covers.

• Housing connections.

• Flanged joints.

• Hydraulic components.

• Oil system connections.

• Industrial valves and fittings.

• Mechanical assemblies requiring fluid-tight joints.

In static sealing applications, there is no intended relative movement between the O-ring and the mating surfaces.

Correct compression and groove geometry are essential for achieving reliable sealing.

Dynamic Sealing Applications

NBR O-rings may be suitable for selected dynamic applications, but the sealing arrangement must be correctly engineered.

Important considerations include:

• Type of movement.

• Relative sliding speed.

• Lubrication conditions.

• Friction and heat generation.

• Risk of O-ring twisting.

• Abrasive wear.

• Operating pressure.

• Extrusion clearance.

• Temperature.

The 110x5.5 mm O-ring should not automatically be used as a substitute for a dedicated piston seal, rod seal or rotary shaft seal.

How to Select the Correct Groove for a 110x5.5 mm O-Ring

Installation Diameter

Determine whether the O-ring will be installed in an internal or external sealing arrangement.

The installation method influences the circumferential stretch or compression of the sealing ring.

Groove Depth

The groove depth must provide suitable compression of the 5.5 mm cross-section.

Insufficient compression can cause leakage.

Excessive compression may accelerate elastomer wear or damage.

Groove Width

The groove width must provide sufficient space for the elastomer to deform.

Incorrect groove filling can reduce sealing reliability.

Extrusion Clearance

In pressurised systems, the clearance between mating components must be considered.

Excessive clearance may allow the elastomer to extrude into the gap.

Depending on the operating conditions, a backup ring may be required.

Surface Finish and Tolerances

The surface finish and dimensional tolerances of the mating components must be selected according to the sealing arrangement and operating conditions.

Universal groove dimensions should not be assigned solely from the nominal O-ring size of 110x5.5 mm.

NBR 70 Shore A vs Other O-Ring Materials

Replacing NBR with FKM, EPDM or VMQ requires verification of chemical compatibility and operating conditions.

Identical dimensions do not automatically make O-rings manufactured from different elastomers interchangeable.

Alternative Designations and Search References

Natural variations of the product designation include:

• O-Ring NBR 110x5.5 mm 70 Shore A

• NBR O-Ring 110x5.5

• O-Ring 110x5.5 NBR 70

• Nitrile Rubber O-Ring 110x5.5 mm

• Buna-N O-Ring 110x5.5 mm

• Oil-Resistant O-Ring 110x5.5 mm

• O-Ring ID 110 mm CS 5.5 mm

• NBR 70 Shore A Sealing Ring 110x5.5 mm

These are alternative written descriptions and search terms, not verified OEM numbers or manufacturer cross-references.

Typical Industrial Applications

NBR 70 Shore A O-rings are used in many industrial sealing systems, including:

• Hydraulic systems using compatible fluids.

• Mineral oil installations.

• Lubrication systems.

• Machinery housings.

• Flanged connections.

• Industrial valves and fittings.

• Mechanical assemblies.

• Appropriately designed dynamic sealing systems.

These are general applications of the O-ring construction and NBR material, rather than verified OEM applications for the specific 110x5.5 mm size.

Installation and Maintenance

Surface Preparation

Clean the sealing groove and mating surfaces before installation.

Contamination can cause local damage and leakage.

Edge Inspection

Sharp edges and burrs can cut the elastomer during installation.

Mounting surfaces should be properly prepared.

Avoid Twisting

Install the O-ring evenly without twisting, excessive stretching or local pinching.

Assembly Lubrication

Where permitted by the application, use a suitable assembly lubricant compatible with NBR and the sealed medium.

Leak Testing

After assembly, verify correct installation and perform the required leakage or pressure test.

Storage

Store O-rings away from direct sunlight, ozone sources, excessive heat and chemical contamination.

Appropriate storage conditions help preserve the properties of the elastomer before installation.

Frequently Asked Questions - O-Ring NBR 110x5.5 mm

What are the dimensions of the 110x5.5 mm O-ring?

The nominal inside diameter is 110 mm, the cross-section diameter is 5.5 mm and the calculated nominal outside diameter is 121 mm.

What does NBR 70 Shore A mean?

NBR identifies nitrile butadiene rubber, while 70 Shore A specifies the nominal hardness of the material on the Shore A scale.

Is the 110x5.5 mm NBR O-ring resistant to oil?

NBR generally offers good resistance to many mineral oils and lubricating greases. Compatibility should be confirmed for the specific medium and operating temperature.

Can this O-ring be used in hydraulic systems?

It may be used in properly designed hydraulic systems with compatible fluids. Operating pressure, temperature and groove geometry must be considered.

Can NBR O-rings be used with water?

NBR may be suitable for certain water applications. However, prolonged exposure to water, particularly hot water, may require a different elastomer such as an appropriate EPDM compound.

Does 70 Shore A determine the maximum operating pressure?

No. Permissible pressure also depends on groove design, extrusion clearance, temperature and the possible use of backup rings.

Can an NBR O-ring be replaced with an FKM O-ring?

Not automatically. The replacement must be evaluated for chemical compatibility, temperature resistance and mechanical properties.

Can the 110x5.5 mm O-ring operate in moving assemblies?

It may be suitable for selected dynamic applications, provided that the sealing system is designed to accommodate the movement, speed, friction, lubrication and wear conditions.

O-Ring NBR 110x5.5 mm 70 Shore A - Key Technical Information

O-ring NBR 110x5.5 mm 70 Shore A is an elastomeric sealing ring with a 110 mm inside diameter and 5.5 mm cross-section. Its calculated nominal outside diameter is 121 mm. Manufactured from nitrile butadiene rubber, it is commonly used with compatible mineral oils and greases. Correct selection requires verification of fluid compatibility, operating temperature, pressure and groove geometry.

NBR O-Rings at simmering.pl

Simmering.pl supplies industrial O-rings, sealing rings and technical sealing solutions for machinery maintenance, engineering departments, industrial procurement and B2B customers.

Correct O-ring selection requires verification of the inside diameter, cross-section diameter, elastomer material and hardness.

Our warehouse and order processing operations are located in Lublin, Poland. We support customers throughout Europe and international markets with technical product identification and shipping options.

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