Xdot patented foil bearing solutions make foil bearing technology available to a broad range of industrial, consumer, and commercial machines. Previously, only an option for aerospace and other niche applications, our approach allows you to leverage foil bearings’ unique benefits, such as:
Foil bearings are hydrodynamic bearings, similar to oil-lubricated journal bearings used in most large machinery, such as steam turbines, generators, or large industrial compressors. At normal operating speeds, the shaft does not come into contact with the bearing surface. Instead, shaft rotation “drags” fluid (air) into a converging region, creating an area of high pressure. This high-pressure fluid (air) between the rotating shaft and the stationary bearing lifts and supports the shaft as it rotates.
The load that can be supported depends on the relative surface speed, the area of the converging region, the shape of the clearance space between the rotating surface and the top foil, the stiffness of the support structure, and the viscosity of the lubricant (which is generally air for foil bearings).
A foil bearing’s unique feature is its compliant operating surface. The surface changes shape depending on load, speed, thermal deformations, and other factors, allowing the bearing to accommodate levels of misalignment and thermal expansion that would otherwise destroy a rigid surface air bearing.
What Foil Bearings Are Not
Foil bearings are not a drop-in replacement for rolling element (ball) bearings. The design constraints and integration requirements differ, so it is best to design a machine with foil bearing capabilities from the outset.
Our cutting-edge foil bearings enable practical, oil-free support systems to operate at moderate to very high shaft surface speeds (50 m/s and above). When conventional rolling element or oil-lubricated bearings won’t work, foil bearings are often the only viable choice. This choice is generally driven by one of three specific machine requirements:
Self-acting, hydrodynamic foil bearings are generally applied in turbomachinery with a power rating smaller than 300 kW. Commercial examples include the air cycle machines used for cabin environmental control and pressurization in nearly every commercial aircraft, microturbine generators, cryogenic expanders, and wastewater treatment blowers.
Foil bearings are being used to enable new, compact, high-speed turbomachinery currently under development for large market applications by multiple original equipment manufacturers.
Xdot Bearings by Barber-Nichols is proud to hold multiple patents related to rotordynamics and foil-bearing technologies, with additional patents pending.
We help make it possible for system developers to build small, high-speed machines for challenging environments.
State-Of-The-Art Performance
Xdot patented foil bearing configuration provides state-of-the-art performance and reduces development and production costs relative to traditional bump foil designs.
Design Flexibility
The unique foil bearing configuration offers more design flexibility, is easier to build and inspect, and features fewer parts compared to conventional bump foil designs.
Experience, Expertise, and Collaboration
Dr. Erik Swanson has been working with foil bearings since 1998. He has been helping companies develop foil-bearing machines since 2003. By the end of 2020, his team shipped over 750 Xdot-designed and produced foil bearings to clients. We excel at serving as the foil-bearing subject-matter expert on client teams.
Research-driven
We deliver prototype foil bearings, including proven near-off-the-shelf foil bearings when applicable. We support our foil bearings with in-house testing capabilities and ongoing research and development, enabling us to continually advance our designs and design tools. Independent customer testing has confirmed the performance of Xdot designs.
If you are planning a new machine and considering foil bearings, we encourage you to contact us early in the design process. We can help your team make informed choices and save you time and money in the long run.
