Xdot Bearing Technologies is committed to helping customers solve unusual and challenging foil bearing and rotordynamics project problems. Our tools, skills, and expertise allow us to produce best-in-class foil bearing products and solutions, provide Rotordynamics Analysis Consulting Services, and deliver Training and Professional Development Courses.
Xdot Foil Bearings for More Applications
Xdot’s patented foil bearing solutions make foil bearing technology available to a broad range of industrial, consumer, and commercial machines. This allows you to take advantage of foil bearings’ unique benefits which were previously only available to aerospace and other niche applications.
What Are Foil Bearings?
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 contact 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 top foil, the support structure stiffness, and the viscosity of the lubricant (which is generally air for foil bearings).
The unique feature of a foil bearing is the compliant operating surface. The surface changes shape depending on load, speed, thermal deformations, etc., to allow the bearing to accommodate levels of misalignment and thermal expansion that would 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 are different so it is best if a machine is designed to take advantage of foil bearing capabilities from the start.
Why Choose Foil Bearings?
Xdot customers choose our solutions because foil bearings can enable new, game changing turbomachinery. Our cutting-edge foil bearings allow practical oil free support systems to operate at moderate to very high shaft surface speeds (50 m/s and up). 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:
- Need for an oil-free bearing system, generally using the process fluid (gas) as the “lubricant”
- Very high shaft surface speeds at the bearing location
- Extreme ambient temperatures in the bearing compartment
Self-acting, hydrodynamic foil bearings are generally applied in turbomachinery 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 is proud to hold the multiple patents related to rotordynamics and foil bearing technologies, with other patents pending.
Why XDot Foil Bearings?
Xdot’s focus is to provide access to foil bearings and foil bearing technology. We help make it possible for system developers to build small, high-speed machines for challenging environments.
Xdot has developed, proven, and patented a novel foil bearing configuration that provides state-of-the-art performance and reduces development and production costs relative to traditional bump foil designs.
Xdot’s unique foil bearing configuration has more design flexibility, is easier to build and inspect, and has fewer parts than conventional bump foil designs.
Experience, Expertise, and Collaboration
Xdot’s founder, Dr. Erik Swanson, has been working with foil bearings since 1998. Xdot has been helping companies with foil bearing machine development since 2003; we shipped the first Xdot designed foil bearing to a client in 2014 and executed our first technology license in 2019. By the end of 2020, Xdot shipped over 750 Xdot designed and produced foil bearings to clients. We excel at working as the foil bearing subject matter expert on client teams.
We deliver prototype foil bearings, including proven, near off-the-shelf foil bearings when applicable. We support our foil bearings with in-house testing capability and ongoing research and development so we can continue to advance our designs and design tools. Independent testing by customers has confirmed the performance of Xdot’s designs.
If you are planning a new machine and want to consider foil bearings, we encourage you to contact us early in the design process. We can help your team make the most efficient choices and save you time and money down the line.
Need more information? Contact us today to learn more about how Xdot Air and Process Gas Lubricated Foil Bearings can help you design smaller, faster, simpler, machines to meet your application’s needs.