Axial Seal AS-11

Construction and design

Applications and why this design fits so well

Material selection (NBR vs FKM)

The sealing lip is available in NBR and FKM. NBR is usually the logical all-round choice for standard oil and grease environments: it’s cost-effective, performs well with mineral lubricating oils and greases, and it is in many cases also suitable for common hydraulic oils. The downside is that NBR ages faster at higher temperatures and is less resistant to ozone, UV and some more aggressive media; hot water is also typically limited (in many applications to around 80 °C). You choose FKM when temperature and/or chemical exposure is more demanding, for example at higher operating temperatures, with synthetic oils, fuels or specific hydraulic fluids. FKM also performs clearly better in terms of ozone resistance, weathering, ageing and UV. On the other side, FKM is generally more expensive and can be less forgiving at low temperatures than NBR. It is important to note that the stated maximum values must not occur simultaneously in practice: if you are close to the temperature limit, you should choose more conservative speed and load conditions, and vice versa.

Material overview

Comparison with similar models

Within the axial seal range, the AS-11 axial seal is often compared to the AS-10 axial seal. The AS-11 type is the more robust version with an axially extended metal casing, allowing you to achieve extra protection and a labyrinth effect if the counterface is designed accordingly. An AS-10 is simpler and may be perfectly sufficient when contamination levels are limited or when there is no space or possibility to incorporate the labyrinth groove. Compared with a radial shaft seal (such as the SC oil seal or the TC oil seal), the AS-11 has a different role: a radial seal is the primary seal to retain oil or grease, whereas the axial seal AS-11 is mainly intended to protect the radial seal and bearings from external influences. In many applications, they therefore work together: an AS-11 on the outside and a radial seal on the inside. Compared with a fully non-contact labyrinth seal, the AS-11 axial seal is generally more compact and easier, while a “true” labyrinth becomes particularly attractive at extremely high speeds and with minimal friction, but often requires more space and tighter machining accuracy.

How to choose the right AS-11

Selection starts with the dimensions and the installation situation. Because the AS-11 axial seal is mounted on the shaft with an interference fit, you choose a version whose inner diameter matches your shaft diameter and the manufacturer’s recommended fits. Next, you look at the counterface: you need a flat surface for the lip to seal against, and if you want to get the most out of the axial seal AS-11 concept, you design a continuous groove in that counterface so the labyrinth seal is created. At the same time, the installation space determines the axial preload: the distance and position of the ring set how firmly the lip is pressed against the counterface. More preloads generally provide a “tighter” seal, but it also increases friction and wear; too little preload can reduce sealing performance. The total axial contact force is influenced not only by the mounting position, but also by the lip geometry and the elastic properties of the selected material.

You should choose the lip material based on the operating conditions: NBR for standard oil/grease and normal temperatures, and FKM for higher temperatures, synthetic oils, fuels and environments where ozone/UV/ageing play a role. Always check the max speed as well (often up to around 12 m/s, depending on conditions) and keep in mind that this type is intended for unpressurised applications (0 MPa). For installation, lightly grease the lip before start-up to reduce initial friction and support service life, and press the ring into position using a suitable installation tool and even force. Do not use a hammer, to avoid damage or misalignment. If axial access is limited, the installation tool must be able to “lock in” the required preload so the ring ends up in the correct position in one operation. Also store the AS-11 axial seal in a way that prevents the lip from being deformed or damaged, because this can directly affect sealing performance.

Cross Reference

In summary, the Axial Seal AS-11 offers superior sealing performance and reliable protection in a wide range of applications. Its simple yet efficient design, small installation width, and excellent sealing capabilities make it an ideal choice for various industries. With the AS-11, you can trust in its ability to safeguard your equipment and machinery from contaminants, ensuring optimal performance and extended lifespan.

If you want more information about Axial seals AS-11, feel free to contact us.

FAQ: Axial Seal AS-11