NBR 25x40x7 AH Rotary Shaft Seal - Single Lip

Applications

The NBR 25x40x7 AH rotary shaft seal is a single-lip oil seal designed for radial sealing of rotating shafts in non-pressurized industrial applications. It is commonly used in machinery, electric motors, gearboxes, pumps, and mechanical assemblies where reliable technical sealing against oil or grease leakage is required during continuous shaft rotation.

Operating Range and Advantages

Manufactured from NBR (nitrile butadiene rubber), the seal offers high resistance to oils and greases, good elasticity, and stable performance under typical industrial conditions. The AH profile indicates a single working lip optimized for low friction and consistent contact with the shaft surface.

Permissible Operating Pressure:

• 0 bar - standard non-pressurized operation

• up to approx. 0.3 bar - short-term, with good shaft alignment

• up to approx. 0.5 bar - maximum, only under ideal conditions (low speed, stable temperature)

The AH design is not a pressure seal. Increasing pressure accelerates lip wear, may cause lip inversion, and shortens service life.

Technical Data

• Type: rotary shaft seal (oil seal)

• Profile: AH

• Inner diameter: 25 mm

• Outer diameter: 40 mm

• Width: 7 mm

• Material: NBR

• Design: single lip

• Operating mode: non-pressurized radial sealing

Main Description

The NBR 25x40x7 AH is a standard single-lip rotary shaft seal for non-pressurized applications requiring dependable sealing and long service life. Its precisely formed sealing lip minimizes leakage while maintaining low friction and controlled wear on the shaft.

NBR material ensures durability and compatibility with common lubricants used in industrial equipment. Compact dimensions allow installation in space-restricted housings, making this seal suitable for both new machine designs and maintenance replacements. For applications exceeding 0.5 bar, alternative sealing solutions such as supported seals, cassette seals, or PTFE-based designs should be considered.

FAQ - Frequently Asked Questions

What pressure can an AH seal handle?
It is intended for non-pressurized use; short-term up to approx. 0.3 bar, maximum approx. 0.5 bar under ideal conditions.

Single lip vs double lip - what’s the difference?
Double-lip seals add a dust lip for contamination protection but do not increase pressure capability.

Is NBR suitable for oil sealing?
Yes, NBR provides excellent resistance to mineral oils and greases.

How do I select the correct seal size?
Match the inner diameter to the shaft, the outer diameter to the housing bore, and the width to the groove depth.