40x55x7 mm NBR AO/TC Double Lip Radial Shaft Seal

40x55x7 mm NBR AO/TC Double Lip Radial Shaft Seal

40x55x7 mm NBR AO/TC is a double lip radial shaft seal manufactured from NBR nitrile rubber. The seal has a primary sealing lip and an additional dust lip designed to provide extra protection against external contamination. Its nominal dimensions are 40x55x7 mm: 40 mm shaft diameter, 55 mm housing bore and 7 mm width.

Technical Data - 40x55x7 NBR AO/TC

What Does 40x55x7 mm Mean?

Radial shaft seal dimensions are commonly specified in the following order:

d x D x b

For this seal:

40x55x7 mm

means:

• 40 mm - nominal shaft diameter,
• 55 mm - nominal housing bore,
• 7 mm - nominal seal width.

Dimensions are one of the primary selection criteria, but they should not be the only factor considered when choosing a replacement.

NBR Nitrile Rubber

This radial shaft seal is manufactured from NBR, or nitrile butadiene rubber.

NBR is one of the most widely used elastomers in industrial sealing technology. It is commonly used in radial shaft seals operating with many oils and greases and in a broad range of mechanical and industrial applications.

Seal selection should nevertheless consider:

• operating medium,
• operating temperature,
• shaft speed,
• lubrication conditions,
• pressure conditions,
• shaft surface condition,
• seal arrangement.

NBR should not be assumed to be compatible with every operating medium solely because it is widely used for oil seals.

AO/TC Double Lip Radial Shaft Seal

The 40x55x7 NBR AO/TC seal has a double lip construction.

The primary sealing lip performs the main sealing function against the rotating shaft.

The second lip provides additional protection from the external side and is commonly referred to as a:

dust lip

or

auxiliary lip

Its purpose is to help reduce the ingress of contaminants into the area of the primary sealing lip.

Primary Sealing Lip and Dust Lip

The primary sealing lip provides the main dynamic sealing function between the rotating shaft and stationary housing.

The additional dust lip provides an extra barrier on the external side of the seal.

Depending on the application, this additional lip can help protect the primary sealing area against contaminants such as:

• dust,
• dirt,
• fine solid particles,
• environmental contamination.

Actual sealing performance always depends on the complete seal arrangement and operating conditions.

What Do AO and TC Mean?

Profile designations for radial shaft seals are not fully standardized across all manufacturers.

AO and TC are designations encountered in the shaft seal market for double lip seal constructions.

However, terminology can vary between manufacturers, so these profile codes should not automatically be assumed to define an identical construction in every product range.

For replacement selection, the most important specification is therefore the actual construction:

40x55x7 mm + NBR + primary sealing lip + additional dust lip

rather than the profile code alone.

Where Is a 40x55x7 NBR Oil Seal Used?

Double lip radial shaft seals are used in many types of machines and mechanical assemblies.

Depending on the requirements of the specific application, a 40x55x7 mm seal may be used in:

• gearboxes,
• reducers,
• industrial machinery,
• agricultural machinery,
• mechanical equipment,
• drive assemblies,
• other rotating shaft systems.

The dimensions alone do not confirm compatibility with any specific machine.

Why Is the Additional Dust Lip Useful?

The primary sealing lip operates directly against the rotating shaft surface and performs the main sealing function.

Contamination reaching this area can adversely affect the operating conditions between the sealing lip and shaft.

The additional dust lip creates another barrier between the surrounding environment and the primary sealing zone.

For this reason, double lip seals are commonly selected for applications where additional protection against external contamination is desirable.

Double Lip vs Single Lip 40x55x7 Seal

A single lip and double lip radial shaft seal with identical dimensions should not automatically be considered technically equivalent.

A double lip design includes an additional protective lip.

When replacing a seal, compare not only:

40x55x7 mm

but also:

material + construction + number of lips + operating conditions

If the original design uses an additional dust lip, changing to a single lip version should only be considered after verifying the requirements of the application.

Can an FKM 40x55x7 Seal Replace an NBR Seal?

Not automatically.

NBR and FKM are different elastomer groups with different material properties.

Changing the material requires consideration of:

• operating medium,
• temperature,
• shaft speed,
• application requirements,
• seal construction.

Identical nominal dimensions alone are not sufficient to confirm interchangeability.

How to Select a 40x55x7 Radial Shaft Seal

When selecting a replacement, verify:

• shaft diameter: 40 mm,
• housing bore: 55 mm,
• width: 7 mm,
• material: NBR,
• construction: double lip,
• presence of an additional dust lip,
• operating medium,
• operating temperature,
• shaft speed,
• environmental conditions,
• requirements of the specific machine.

If replacing an existing seal, it is also useful to compare the actual construction and geometry of the removed component.

Installation of a 40x55x7 Oil Seal

Before installation, carefully inspect the shaft surface and seal housing.

The surface operating against the primary sealing lip should be free from:

• corrosion,
• burrs,
• sharp edges,
• excessive wear grooves,
• contamination.

During installation, protect the sealing lip from threads, splines, grooves and other sharp shaft features.

The seal should be pressed evenly into the housing using a suitable installation tool to avoid tilting or deformation.

Correct orientation should be maintained according to the design of the sealed assembly.

Alternative References and Search Terms

This product may be searched as:

40x55x7 oil seal

40x55x7 NBR oil seal

40x55x7 AO oil seal

40x55x7 TC oil seal

40x55x7 double lip oil seal

40x55x7 shaft seal

40x55x7 NBR shaft seal

40x55x7 radial shaft seal

40x55x7 double lip seal

40x55x7 dust lip seal

NBR oil seal 40x55x7

TC oil seal 40x55x7

AO oil seal 40x55x7

double lip radial shaft seal 40x55x7

Simmerring 40x55x7 NBR

These search terms cover the most common dimensional, material and construction-based methods of identifying the product.

FAQ

What are the dimensions of this radial shaft seal?

The seal measures 40x55x7 mm: 40 mm inner diameter, 55 mm outer diameter and 7 mm width.

What material is the 40x55x7 seal made from?

The seal is manufactured from NBR nitrile rubber.

Is this a double lip oil seal?

Yes. It has a primary sealing lip and an additional protective dust lip.

What does TC mean on an oil seal?

TC is a designation commonly encountered for double lip radial shaft seals. However, profile nomenclature may vary between manufacturers, so the actual seal construction should always be verified.

What does AO mean?

AO is another profile designation encountered in shaft seal catalogues. Because terminology differs between manufacturers, the designation should be considered together with the actual construction of the seal.

Is every 40x55x7 oil seal the same?

No. Seals with identical dimensions may differ in material, number of sealing lips, profile, outer surface construction and intended operating conditions.

Can a single lip 40x55x7 seal replace this double lip version?

Not automatically. This product has an additional dust lip. The requirements of the specific application should be checked before changing to a single lip design.

Can FKM be used instead of NBR?

Changing from NBR to FKM requires verification of the operating medium, temperature, shaft speed and other application conditions. Identical dimensions do not automatically confirm interchangeability.

40x55x7 NBR AO/TC - Quick Answer

40x55x7 mm NBR AO/TC is a double lip radial shaft seal for a nominal 40 mm shaft and 55 mm housing bore, with a width of 7 mm. It is manufactured from NBR nitrile rubber and features a primary sealing lip plus an additional dust lip. Replacement selection should consider the material and double lip construction, not dimensions alone.

Available from simmering.pl, a specialist B2B supplier of radial shaft seals, V-rings, O-rings, bearings and industrial sealing solutions. Products are shipped worldwide from stock in Poland.