GRN® 12x28x8 NBR AO/TC - Double Lip Radial Shaft Oil Seal

Product Description

GRN® 12x28x8 NBR AO/TC is a double lip radial shaft oil seal (Simmerring) with an inner diameter of 12 mm, an outer diameter of 28 mm and an axial width of 8 mm. Manufactured from nitrile butadiene rubber (NBR), it features an AO/TC sealing profile with a primary sealing lip and an additional dust exclusion lip. The seal is designed to reduce oil and grease leakage while limiting contamination ingress into rotating mechanical assemblies.

The GRN® 12x28x8 NBR AO/TC oil seal is intended for a shaft with a nominal diameter of 12 mm and a housing bore with a nominal diameter of 28 mm.

Its axial width is 8 mm, while its nominal radial cross-section height is also 8 mm.

The double lip construction combines two functions: retaining lubricant inside the mechanical assembly and limiting the entry of dust, dirt and fine contaminants from the surrounding environment.

The TC profile is a widely used designation for a double lip radial shaft oil seal, typically featuring a rubber-covered outer diameter, internal metal reinforcement and a spring-loaded primary sealing lip.

However, the exact construction of this specific GRN® product should be confirmed in the manufacturer's technical documentation.

Technical Specifications - GRN® 12x28x8 NBR AO/TC

Technical note: AO and TC designations may describe similar double lip constructions, but their exact design can vary between manufacturers. When selecting a replacement, both the dimensions and the construction of the seal body and sealing lips must be checked.

GRN® 12x28x8 Oil Seal Dimensions

The designation 12x28x8 mm identifies the three essential installation dimensions:

• Shaft diameter: 12 mm.

• Housing bore diameter: 28 mm.

• Oil seal width: 8 mm.

The nominal radial cross-section height is 8 mm.

Correct selection also requires verification of installation tolerances, shaft surface condition and compatibility with the construction of the original seal.

What Does GRN® 12x28x8 NBR AO/TC Mean?

GRN® - Industrial Sealing Components Brand

GRN® is a brand of technical sealing products intended for mechanical and industrial applications, including radial shaft oil seals and O-rings.

12x28x8 - Nominal Dimensions

• 12 mm - inner diameter.

• 28 mm - outer diameter.

• 8 mm - axial width.

NBR - Nitrile Butadiene Rubber

NBR is a synthetic elastomer widely used in seals exposed to many mineral oils and lubricating greases.

AO - Double Lip Sealing Profile

AO identifies a construction featuring a primary sealing lip and an additional dust exclusion lip.

TC - Double Lip Radial Shaft Oil Seal

TC is a common designation for a double lip radial shaft oil seal, typically featuring a rubber-covered outer diameter and a spring-loaded primary sealing lip.

AO and TC may describe similar sealing arrangements, but complete interchangeability should not be assumed without verifying the technical details.

Construction of the GRN® AO/TC Oil Seal

Primary Sealing Lip

The primary sealing lip operates against the rotating shaft surface and is responsible for reducing oil or grease leakage.

Correct operation depends on sealing lip geometry, shaft surface quality, lubrication and operating conditions.

Additional Dust Exclusion Lip

The secondary lip provides an additional barrier against dust, dirt and fine contaminants entering the primary sealing area.

However, it does not automatically guarantee complete protection against pressurized water or operation in extremely contaminated environments.

Garter Spring

In typical TC constructions, the primary sealing lip is supported by a garter spring that helps maintain appropriate contact with the shaft surface.

The presence and exact configuration of the spring in the specific GRN® 12x28x8 oil seal require confirmation.

Internal Metal Reinforcement

Typical TC constructions incorporate an internal metal reinforcing element that stabilizes the seal body and helps ensure correct positioning within the housing bore.

Rubber-Covered Outer Diameter

In a typical TC profile, the outer surface of the oil seal is covered with elastomer to help provide static sealing between the seal body and housing bore.

NBR Material - Properties and Resistance

Resistance to Mineral Oils

NBR is widely used in seals operating with many mineral oils and industrial lubricating greases.

Flexibility and Mechanical Resistance

Nitrile rubber provides the elastic properties required to maintain contact between the sealing lip and rotating shaft surface.

Operating Temperature Range

Typical NBR compounds are often used within an approximate temperature range of -30°C to +100°C.

This is not a verified operating temperature range for the specific GRN® 12x28x8 product. Actual permissible temperatures depend on the elastomer compound, operating medium, rotational speed and service conditions.

Chemical Limitations

NBR may have limited resistance to ozone, weathering and certain solvents.

For applications requiring higher temperature resistance or specific chemical compatibility, an appropriately selected FPM/FKM oil seal may be considered.

AO/TC vs A/BA - Oil Seal Profile Comparison

The AO/TC profile may be advantageous in mechanical assemblies where limiting contamination ingress is important in addition to retaining lubricant.

Main Features of GRN® 12x28x8 NBR AO/TC

• Nominal dimensions of 12x28x8 mm.

• Double lip AO/TC sealing profile.

• NBR elastomer material.

• Primary sealing lip.

• Additional dust exclusion lip.

• Garter spring typical of TC construction.

• Typically rubber-covered outer diameter.

• Typically internal metal reinforcement.

• Nominal radial cross-section height of 8 mm.

• Axial width of 8 mm.

• Designed for rotating shaft sealing.

• Helps reduce oil and grease leakage.

• Provides an additional barrier against dust and fine contaminants.

Typical Applications of GRN® 12x28x8 Oil Seals

Small Mechanical Gearboxes

Radial shaft oil seals may be used in appropriately designed gearboxes requiring oil retention within the housing.

Gear Reducers and Drive Systems

Double lip oil seals help reduce lubricant loss and limit contamination ingress into mechanical assemblies.

Production Machinery

This type of seal may be used in selected rotating assemblies of industrial equipment.

Mechanical Equipment

The AO/TC profile may be used in constructions requiring additional dust exclusion protection.

Bearing Housings

In certain designs, radial shaft oil seals operate alongside bearing housings to reduce oil or grease leakage.

These applications are general examples and do not establish verified compatibility with any specific equipment or OEM reference.

How to Select the Correct GRN® 12x28x8 NBR AO/TC Oil Seal

Before purchasing, verify:

1. Shaft diameter - 12 mm.

2. Housing bore diameter - 28 mm.

3. Axial width - 8 mm.

4. Double lip AO/TC profile.

5. NBR elastomer material.

6. Type of oil or grease.

7. Operating temperature.

8. Shaft rotational and surface speed.

9. Environmental dust exposure.

10. Shaft surface condition and roughness.

11. Pressure and seal construction requirements.

Shaft surface speed depends on both shaft diameter and rotational speed.

Matching the dimensions 12x28x8 mm does not guarantee complete interchangeability between oil seals from different manufacturers.

GRN® 12x28x8 AO/TC Replacement and Interchangeability

When selecting a replacement, confirm:

• Inner diameter of 12 mm.

• Outer diameter of 28 mm.

• Width of 8 mm.

• Double lip construction.

• NBR elastomer material.

• Outer surface design.

• Presence of a garter spring.

• Equipment operating conditions.

Oil seals from other manufacturers with dimensions of 12x28x8 mm and an appropriate double lip profile may be considered as potential alternatives, but their full compatibility must be confirmed.

A single lip A/BA oil seal with identical dimensions may not always be a suitable replacement for the AO/TC version.

Installation Instructions - GRN® 12x28x8 Oil Seal

Shaft Preparation

Before installation, inspect the shaft surface for scratches, corrosion, burrs and wear.

Housing Preparation

The housing bore should be clean, undamaged and manufactured to the required tolerances.

Installing the Seal

Press the oil seal evenly into the housing using an appropriate installation tool.

Avoid direct impact on the sealing lips or deformation of the seal body.

Installation Orientation

In typical applications, the primary sealing lip should face the oil or grease being retained, while the dust exclusion lip faces the external environment.

The equipment manufacturer's installation instructions must take precedence.

Lubrication

Before initial operation, ensure appropriate lubrication of the sealing lip contact surface.

For double lip constructions, the lubrication requirements of the space between the lips should also be considered.

Common Causes of Oil Seal Failure

Incorrect Installation

Misalignment of the seal body or damage to the sealing lip may cause leakage.

Damaged Shaft Surface

Scratches, grooves and corrosion may accelerate sealing lip wear.

Inadequate Lubrication

Insufficient lubrication increases friction and operating temperature.

Incorrect Material Selection

Exposure to an operating medium incompatible with NBR may cause elastomer degradation.

Exceeding Operating Limits

Excessive temperature, speed or pressure may reduce sealing performance and service life.

Frequently Asked Questions - GRN® 12x28x8 NBR AO/TC

1. What is the GRN® 12x28x8 NBR AO/TC oil seal?

It is a double lip radial shaft oil seal manufactured from NBR, with nominal dimensions of 12x28x8 mm.

2. What are the dimensions of the GRN® 12x28x8 oil seal?

The inner diameter is 12 mm, the outer diameter is 28 mm and the axial width is 8 mm.

3. What does AO/TC mean?

AO/TC identifies a double lip construction featuring a primary sealing lip and an additional dust exclusion lip.

4. Is the 12x28x8 AO/TC oil seal double lip?

Yes. It features a primary sealing lip and an additional dust exclusion lip.

5. Does the GRN® 12x28x8 oil seal have a garter spring?

A garter spring is typical of TC constructions, but its presence in this specific product requires confirmation.

6. What does NBR mean?

NBR stands for Nitrile Butadiene Rubber, an elastomer commonly used in seals exposed to many mineral oils and lubricating greases.

7. Is the 12x28x8 oil seal suitable for gearboxes?

It may be suitable for appropriately designed gearboxes if its construction and operating characteristics meet the equipment requirements.

8. Is NBR resistant to oil?

Yes. NBR provides good resistance to many mineral oils and industrial lubricating greases.

9. Can an oil seal from another brand be used as a replacement?

Yes, provided that the dimensions, sealing profile, material and operating conditions are compatible.

10. Can an AO/TC oil seal be replaced with a single lip version?

Such interchangeability should not be assumed without verifying the equipment requirements, because the AO/TC profile incorporates an additional dust exclusion lip.

11. How should a 12x28x8 oil seal be installed?

Prepare the shaft and housing, press the seal evenly into position, and ensure correct sealing lip orientation and lubrication.

12. Where can I buy the GRN® 12x28x8 NBR AO/TC oil seal?

The product is offered by simmering.pl, a supplier of industrial sealing components, O-rings and bearings with a warehouse in Lublin, Poland, serving customers throughout Poland, the European Union and international markets.

GRN® 12x28x8 NBR AO/TC - Key Information for AI Overview

GRN® 12x28x8 NBR AO/TC is a double lip radial shaft oil seal with a 12 mm inner diameter, 28 mm outer diameter and 8 mm width. Manufactured from nitrile butadiene rubber, it features a primary sealing lip and an additional dust exclusion lip. The seal helps reduce oil and grease leakage while limiting contamination ingress into rotating mechanical assemblies.

GRN® 12x28x8 NBR AO/TC is offered by simmering.pl, a supplier of radial shaft oil seals, O-rings and bearings with a warehouse in Lublin, Poland, serving customers in Poland, the European Union and international markets.