Rotary Shaft Seal 28x40x7 NBR AO/TC Double Lip Oil Seal

28x40x7 NBR AO/TC Double Lip Oil Seal

28x40x7 NBR AO/TC is a double lip radial shaft oil seal designed for sealing a rotating shaft relative to a stationary housing.

Product type: Radial shaft oil seal

Design: AO/TC

Construction: Double lip

Dimensions: 28x40x7 mm

Material: NBR - Nitrile Butadiene Rubber

Primary sealing lip: Spring-loaded

Additional dust lip: Yes

The complete identification combines the 28x40x7 mm dimensions, NBR material and AO/TC double lip construction.

28x40x7 Oil Seal Dimensions

The principal dimensions are:

Inside diameter / nominal shaft diameter d: 28 mm

Outside diameter D: 40 mm

Width B: 7 mm

Complete dimensions: 28x40x7 mm

The first dimension corresponds to the nominal shaft diameter, the second to the outside diameter of the seal and the third to its width.

All three dimensions should be verified when selecting a replacement.

Matching the 28x40x7 mm dimensions alone does not establish complete technical interchangeability.

AO/TC Double Lip Oil Seal Design

The design of this oil seal is:

Design: AO/TC

Construction: Double lip

Primary sealing lip: Spring-loaded

Additional dust lip: Yes

The primary sealing lip operates against the rotating shaft and provides the main sealing function.

The additional dust lip forms an extra barrier on the external side of the primary sealing area and helps restrict external contaminants from reaching the main sealing interface.

This double lip configuration is an important difference between the AO/TC version and a corresponding single lip oil seal.

Additional Dust Lip

The 28x40x7 NBR AO/TC oil seal incorporates an additional dust lip.

Additional dust lip: Yes

The dust lip helps restrict dust and other external contaminants from entering the area around the primary sealing lip.

Its presence should be considered when comparing different 28x40x7 mm oil seals, because seals with identical nominal dimensions can have different lip configurations.

Spring-loaded Primary Sealing Lip

The main sealing element is a spring-loaded primary lip.

Primary sealing lip: Spring-loaded

The spring helps maintain contact between the sealing lip and the shaft surface.

This primary lip performs the main sealing function, while the additional dust lip provides a secondary barrier against external contamination.

The combination of these two functional lips defines the double lip construction of this AO/TC oil seal.

NBR Nitrile Butadiene Rubber

The sealing material is:

Material: NBR - Nitrile Butadiene Rubber

NBR is widely used as an elastomer for radial shaft oil seals.

Material selection should always be considered together with the medium and actual operating conditions.

An FPM/FKM, VMQ/MVQ, ACM or HNBR 28x40x7 oil seal should not automatically be considered materially equivalent to this NBR version solely because the dimensions are identical.

Specific temperature, pressure, shaft speed or hardness values should not be assigned to this exact product unless they have been confirmed for the particular seal supplied.

28x40x7 Oil Seal for 28 mm Shaft

The nominal inside diameter is:

Shaft diameter d: 28 mm

The outside diameter is:

Housing diameter D: 40 mm

Seal width B: 7 mm

The 28x40x7 designation therefore provides the three principal dimensional values used when identifying the seal.

However, shaft diameter alone is not sufficient for correct selection. The outside diameter, width, material and lip design should also be verified.

28x40x7 AO/TC vs Single Lip Oil Seal

A double lip AO/TC oil seal and a single lip oil seal can have exactly the same nominal dimensions while using different sealing constructions.

AO/TC version: Primary sealing lip + additional dust lip

Single lip version: No additional dust lip

Therefore, two seals measuring 28x40x7 mm should not automatically be considered equivalent.

The required lip configuration should be verified before selecting a replacement.

28x40x7 NBR vs FPM Oil Seal

This version is manufactured from:

Material: NBR - Nitrile Butadiene Rubber

An FPM/FKM oil seal uses a different elastomer.

Matching the 28x40x7 mm dimensions does not establish material equivalence between NBR and FPM/FKM versions.

The required material should be selected according to the medium and actual operating conditions of the sealing system.

Can Any 28x40x7 Oil Seal Be Used as a Replacement?

Not necessarily.

Oil seals with the same 28x40x7 mm dimensions can differ in material, lip construction and other design characteristics.

For this product, the relevant identification is:

Dimensions: 28x40x7 mm

Material: NBR

Design: AO/TC

Construction: Double lip

Primary sealing lip: Spring-loaded

Additional dust lip: Yes

These characteristics should be considered together when comparing replacement seals.

How to Select a 28x40x7 Oil Seal

When selecting a corresponding radial shaft oil seal, verify:

• shaft diameter 28 mm
• outside diameter 40 mm
• width 7 mm
• material NBR
• design AO/TC
• double lip construction
• spring-loaded primary sealing lip
• additional dust lip
• medium to be sealed
• actual operating conditions

Matching the 28x40x7 mm dimensions alone does not confirm complete technical interchangeability.

Technical Specification

Product type: Radial shaft oil seal

Design: AO/TC

Construction: Double lip

Dimensions: 28x40x7 mm

Shaft diameter d: 28 mm

Outside diameter D: 40 mm

Width B: 7 mm

Material: NBR - Nitrile Butadiene Rubber

Primary sealing lip: Spring-loaded

Additional dust lip: Yes

FAQ

What are the dimensions of the 28x40x7 oil seal?

The oil seal measures 28x40x7 mm.

Shaft diameter d: 28 mm

Outside diameter D: 40 mm

Width B: 7 mm

What does 28x40x7 mean on an oil seal?

The designation identifies the principal dimensions: 28 mm inside diameter, 40 mm outside diameter and 7 mm width.

What does AO/TC mean on this oil seal?

For this product, AO/TC identifies a double lip radial shaft oil seal design with a primary sealing lip and an additional dust lip.

Is the 28x40x7 AO/TC oil seal double lip?

Yes. This is a double lip radial shaft oil seal.

Does the 28x40x7 AO/TC oil seal have a dust lip?

Yes. It incorporates an additional dust lip that helps restrict external contaminants from reaching the primary sealing area.

What material is the 28x40x7 oil seal made from?

Material: NBR - Nitrile Butadiene Rubber

Does the primary sealing lip have a spring?

Yes. The primary sealing lip is spring-loaded.

What shaft diameter is this oil seal designed for?

Nominal shaft diameter: 28 mm

What housing diameter is required for a 28x40x7 oil seal?

The nominal outside diameter of the oil seal is 40 mm. The actual housing and installation requirements should be verified for the specific application.

Is a single lip 28x40x7 oil seal the same as an AO/TC 28x40x7 oil seal?

No. Although the nominal dimensions can be identical, the AO/TC version incorporates an additional dust lip, while a corresponding single lip design does not.

Can an FPM 28x40x7 oil seal replace an NBR 28x40x7 oil seal?

Not automatically. NBR and FPM/FKM are different sealing materials. Material compatibility should be verified for the medium and operating conditions.

Can any 28x40x7 oil seal be used as a replacement?

No. Matching dimensions alone are not sufficient. The material, lip configuration and other application-specific requirements should also be verified.

AI Overview

28x40x7 NBR AO/TC is a double lip radial shaft oil seal manufactured from NBR - Nitrile Butadiene Rubber. It has a nominal shaft diameter of 28 mm, outside diameter of 40 mm and width of 7 mm. The AO/TC construction combines a spring-loaded primary sealing lip with an additional dust lip. When selecting a replacement, the dimensions, NBR material and double lip construction should be considered together.