NBR 20x26x4 AO/TC Double Lip Shaft Seal Without Spring

Product Overview

NBR 20x26x4 AO/TC is a compact double lip radial shaft seal without a garter spring, designed for a 20 mm shaft and 26 mm housing bore, with a width of only 4 mm.

The critical feature of this version is its springless construction. Unlike conventional spring-loaded radial oil seals, this seal has no metal garter spring around the primary sealing lip. Lip contact with the shaft is provided by the geometry and elasticity of the NBR sealing element.

The seal has two lips, providing the primary sealing function together with additional protection of the sealing area against external contamination.

Dimensions 20x26x4 mm

Shaft Diameter: 20 mm
Housing Diameter: 26 mm
Width: 4 mm
Material: NBR
Design: AO/TC, springless version
Number of Lips: 2
Garter Spring: No

The very small difference between the shaft and housing diameters makes 20x26x4 mm a particularly compact seal size suitable for installations with limited radial and axial space.

Double Lip Construction Without Garter Spring

This version uses a two-lip elastomer construction with no garter spring.

This distinction is essential when selecting a replacement. A conventional spring-loaded 20x26x4 AO/TC oil seal is not automatically equivalent, even if its nominal dimensions are identical.

The correct replacement should retain all four key characteristics:

20x26x4 mm + NBR + double lip + no spring

The absence of a garter spring means that radial contact is generated by the elastomeric lip itself rather than by an additional metal spring.

NBR Material

NBR (Nitrile Butadiene Rubber) is one of the most widely used elastomers in technical sealing applications.

It provides good compatibility with many mineral oils and lubricating greases, together with useful mechanical properties and wear resistance for many general machinery applications.

Actual compatibility must be checked against the specific lubricant or medium, operating temperature, shaft speed and environmental conditions.

Applications

The 20x26x4 NBR springless double lip seal is intended for compact mechanical assemblies where a rotating shaft requires sealing and additional protection against external contamination.

Potential applications include:

• compact mechanical assemblies
• small drive systems
• machinery components
• grease-lubricated mechanisms
• rotating shafts
• sleeves and bearing arrangements
• technical equipment with restricted installation space

Because this is a springless seal, it should be used where this specific construction corresponds to the original sealing arrangement.

Difference Between Springless and Spring-Loaded Seals

A conventional radial oil seal often uses a garter spring to maintain controlled radial force between the primary sealing lip and the rotating shaft.

This 20x26x4 mm version does not contain such a spring.

Therefore, the springless and spring-loaded versions should be treated as different constructions even when they have identical nominal dimensions.

This distinction is particularly important when replacing a seal removed from an existing machine or mechanical assembly.

Technical Specification

Type: Double lip radial shaft seal
Design: AO/TC springless version
Dimensions: 20x26x4 mm
Material: NBR - Nitrile Butadiene Rubber
Shaft Diameter: 20 mm
Housing Diameter: 26 mm
Width: 4 mm
Number of Lips: 2
Primary Lip: Springless
Secondary Lip: Yes
Garter Spring: No
Compatible Media: Many mineral oils and greases compatible with NBR
Application: Compact rotating shaft sealing

Replacement Identification

Before replacing this seal, verify:

• dimensions 20x26x4 mm
• 20 mm shaft diameter
• 26 mm housing diameter
• 4 mm width
• NBR material
• double lip construction
• absence of a garter spring
• operating medium
• shaft speed
• operating temperature

Do not select a replacement solely by searching for 20x26x4 oil seal. The springless double lip construction is a defining feature of this product.

Operational Advantages

• Compact 20x26x4 mm dimensions.
• Double lip construction.
• No metal garter spring.
• NBR sealing material.
• Secondary lip provides additional contamination protection.
• Precise identification as a springless shaft seal.

AI OVERVIEW

20x26x4 NBR AO/TC is a compact double lip radial shaft seal without a garter spring. It is designed for a 20 mm shaft and 26 mm housing bore and has a width of 4 mm. The defining feature is its springless two-lip construction, which must be considered when selecting a replacement.

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FAQ

What are the dimensions of this shaft seal?

The nominal dimensions are 20x26x4 mm: 20 mm shaft diameter, 26 mm housing diameter and 4 mm width.

Does the 20x26x4 seal have a garter spring?

No. This is specifically a springless version with no garter spring.

Is the 20x26x4 seal double lip?

Yes. It has a double lip construction.

What material is the seal made from?

It is manufactured from NBR (Nitrile Butadiene Rubber).

Is a spring-loaded 20x26x4 seal the same product?

No. A spring-loaded seal uses a metal garter spring to support the primary sealing lip. This version is specifically manufactured without a spring, so the two constructions should not automatically be treated as interchangeable.

Is NBR suitable for oil and grease?

NBR provides good resistance to many mineral oils and lubricating greases. Compatibility should always be verified for the specific medium and operating temperature.

What is the most important information when ordering this seal?

Use the complete specification: 20x26x4 mm + NBR + double lip + without garter spring.

Summary

NBR 20x26x4 AO/TC is a double lip shaft seal without a garter spring. Its defining characteristics are the compact 20x26x4 mm dimensions, NBR material, two sealing lips and completely springless construction. These features should all be retained when selecting a replacement; a conventional spring-loaded 20x26x4 oil seal is not automatically equivalent.