Oil Seal 26x47x7 NBR AO/TC Double Lip GRN

What Is the 26x47x7 NBR AO/TC GRN Oil Seal?

Oil Seal 26x47x7 NBR AO/TC GRN is a double-lip radial shaft seal designed for sealing rotating shafts. It has a 26 mm inside diameter, 47 mm outside diameter and 7 mm width. Manufactured from NBR (Nitrile Butadiene Rubber, Buna-N), it is suitable for many applications involving mineral oils and lubricating greases. The AO/TC double-lip design combines a spring-loaded primary sealing lip with an additional dust lip that helps protect the sealing area against external contamination.

Technical Specification

Brand: GRN

Product Type: Oil Seal / Radial Shaft Seal

Design: AO / TC

Construction: Double Lip

Material: NBR, Nitrile Butadiene Rubber, Buna-N

Shaft Diameter d: 26 mm

Outside Diameter D: 47 mm

Width b: 7 mm

Dimensions: 26x47x7 mm

Primary Lip: Spring-loaded sealing lip

Secondary Lip: Dust protection lip

Colour: Black

Typical NBR Temperature Range: approximately -30°C to +100°C

Media Compatibility: mineral oils, lubricating greases and other fluids compatible with NBR

Applications: rotating shafts, gearboxes, reducers, pumps, drives and industrial machinery

What Does AO/TC Mean in an Oil Seal?

The AO/TC designation refers to a double-lip radial shaft seal construction. The primary spring-loaded lip operates directly against the rotating shaft and is responsible for retaining the lubricant inside the mechanism.

The secondary lip provides additional protection from the external environment.

This construction helps to:

• Retain oil inside the mechanism
• Retain lubricating grease
• Reduce lubricant leakage
• Limit dust ingress
• Protect the primary sealing area
• Reduce contamination around the shaft contact surface

Design terminology can vary between manufacturers, so both dimensions and actual lip configuration should be checked when selecting an equivalent seal.

Double-Lip Oil Seal with Dust Lip

Compared with a basic single-lip radial shaft seal, the AO/TC design incorporates an additional protective lip.

The primary sealing lip is responsible for controlling lubricant at the shaft interface. The secondary dust lip is positioned toward the external side and provides an additional barrier against dust and other contaminants.

This makes the double-lip design particularly useful in machinery operating in environments where external contamination may reach the shaft sealing area.

Applications of the 26x47x7 NBR Oil Seal

The GRN 26x47x7 NBR oil seal can be used in appropriately designed sealing arrangements such as:

• Gearboxes
• Gear reducers
• Pumps
• Drive shafts
• Electric motors
• Industrial machinery
• Agricultural machinery
• Production equipment
• Mechanical drive systems
• Workshop equipment

Before installation, verify the shaft and housing dimensions, operating medium, temperature, rotational speed and environmental conditions.

Why Is NBR Used for Oil Seals?

NBR (Nitrile Butadiene Rubber) is one of the most widely used elastomers for standard radial shaft seals.

Its important technical properties include:

• Very good resistance to many mineral oils
• Good resistance to lubricating greases
• Good abrasion resistance
• Suitable elasticity
• Good mechanical properties
• Wide applicability in machinery sealing systems

For these reasons, NBR oil seals are widely used in gearboxes, reducers and other oil or grease lubricated mechanical systems.

How Does a 26x47x7 Oil Seal Work?

The oil seal is installed stationary in the housing while its primary sealing lip operates against the rotating shaft.

For the 26x47x7 mm size:

26 mm is the nominal shaft diameter.

47 mm is the nominal outside diameter of the seal.

7 mm is the seal width.

A garter spring applies controlled radial force to the primary sealing lip, helping maintain contact between the elastomer and the rotating shaft surface.

Oil Seal for Oil and Grease Applications

The NBR material makes the 26x47x7 GRN oil seal particularly suitable for applications involving compatible mineral oils and lubricating greases.

Typical functions include retaining lubricant inside a gearbox, reducer, bearing arrangement or other mechanical assembly.

Actual material compatibility depends on the specific lubricant formulation, additives, operating temperature and application conditions.

Oil Seal Applications in Gearboxes and Machinery

A radial shaft seal is an important component in rotating mechanical systems because it separates the lubricated internal area from the external environment.

The 26x47x7 NBR AO/TC can be considered for suitable:

• Transmission shafts
• Gearbox shafts
• Pump shafts
• Reduction gear units
• Industrial drives
• Machinery assemblies
• Agricultural equipment
• Maintenance and repair applications

The final selection should always be based on the technical requirements of the specific machine.

Installation of the 26x47x7 Oil Seal

Before installing a new oil seal, clean the housing and inspect the shaft contact surface.

During installation:

• Verify the 26 mm shaft diameter
• Verify the 47 mm housing diameter
• Protect the sealing lip from sharp edges
• Avoid damaging the garter spring
• Press the seal evenly into the housing
• Do not deform the outer surface
• Check the correct installation direction
• Protect the primary lip from dry running during initial operation

The primary spring-loaded sealing lip should normally face the oil or other medium that must be retained.

Replacing a Worn Radial Shaft Seal

Typical symptoms indicating that the oil seal should be inspected include:

• Oil leakage around the shaft
• Grease appearing outside the housing
• Hardened sealing lip
• Cracks in the elastomer
• Mechanical damage
• Loss of lip elasticity
• Contamination entering the mechanism

The shaft surface should also be inspected during replacement. A worn groove, corrosion or surface damage can cause leakage even after a new oil seal has been installed.

How to Select a 26x47x7 Oil Seal Replacement

Dimensions alone are not always sufficient when selecting a replacement.

Verify:

• 26x47x7 mm dimensions
• NBR material
• Double-lip construction
• AO/TC design
• Dust protection lip
• Operating medium
• Temperature
• Shaft speed
• Environmental conditions

Replacing a double-lip seal with a single-lip version may reduce protection against external contamination.

Frequently Asked Questions FAQ

What do the 26x47x7 dimensions mean?
The oil seal is designed for a 26 mm nominal shaft diameter, has a 47 mm outside diameter and is 7 mm wide.

Is the GRN 26x47x7 oil seal double-lipped?
Yes. The AO/TC design features a primary sealing lip and an additional dust protection lip.

Is an NBR oil seal suitable for mineral oil?
Yes. NBR provides very good resistance to many mineral oils and is widely used in radial shaft sealing applications.

What is the purpose of the second lip?
The secondary lip helps reduce the ingress of dust and other external contaminants into the primary sealing area.

Can the 26x47x7 oil seal be used in a gearbox?
Yes, provided its dimensions, NBR material and operating parameters meet the requirements of the specific gearbox.

Frequently Asked Questions from Mechanics and Maintenance Engineers

Which direction should the oil seal be installed?
The primary spring-loaded sealing lip should normally face the oil or lubricant that needs to be retained inside the mechanism.

Should the sealing lip be lubricated before installation?
In typical oil applications, the sealing contact should not begin operation completely dry. Use a lubricant compatible with NBR and the operating medium.

Can an AO/TC seal be replaced with a single-lip oil seal?
Not always. Removing the secondary lip reduces protection of the primary sealing area against external contaminants.

Can NBR be replaced with FKM/FPM?
Material substitution should be based on operating temperature, medium, shaft speed and equipment requirements. Matching dimensions alone are not sufficient.

Why can a new oil seal still leak?
Possible causes include a worn shaft surface, incorrect installation direction, damaged sealing lip, misalignment, unsuitable material, incorrect housing fit or an inappropriate seal design.