Most things that turn, do so on bearings. Over the years, much attention has been paid to the bearing. The basic ball bearing has been mastered to reduce friction to incredibly low levels. The automotive drivetrain would not be possible without the friction reducing ability of the ball bearing.
Accuracy in machining of the bearing parts and lubrication technologies have become incredibly sophisticated. Some of the latest innovations include the use of ceramics rolling elements instead of metal on metal contact, and whole new classes of fluorine based lubricants that survive incredible temperatures.
There are a number of applications where conventional bearings are not usable. The inherent vibration of bearings may be unacceptable. Creation of particulates can be a problem in some situations. The alternative is fluidized bearings. Fluidized bearings are designed using precision flat surfaces with grooves that allow oil to form a film between the moving parts. So the parts are literally riding on a layer of oil, no contact between moving parts.
Fluidized bearings have successfully taken over the spindle drive motors on hard disk drives, which is a really tough application, 10,000 rpm and starting and stopping in 2ms. On the opposite end of the power spectrum, I worked with a company that makes machines that make the cans for beer. The machines form the can body using impact extrusion with a 75 horsepower drive and a massive inertia flywheel. The linear motion of the forming tool runs on fluidized bearings. Very cool stuff!
But what do you do when conventional bearings won’t do it, and even a fluidized bearing won’t work? The ideal fluid is air. And thanks to some really creative engineering at New Way Air Bearings, the superior performance of air bearing is available as an off the shelf technology.
New Way Air Bearings are based on a porous carbon media that allow air to flow through it at a controlled rate so that a cushion of air is formed on the face of the media. Parts are suspended on 5 millionths of an inch. And there is no contact, so there is no wear, no particulates, no lubricant. Pretty awesome stuff.
Air bearings are available, from stock, in rectangular pad forms, round journals and radial designs. You can see a great animation of the radial air bearing used in MRI machines on the company’s website. Medical imaging depends on extremely precise motion and NO vibration. A perfect application for air bearings. New Way has also done a number of applications in the semiconductor arena that combine air bearings and vacuum barriers in the same assembly.
One of the great subtleties of bearings is their concentricity. There are many applications in cutting and shaping operations where the active tool is rotating at high speed to shape a desired part. But slight errors in the rotary precision of the tool become exaggerated at high speeds. But with air gaps of 5 millionths of an inch, and the high stiffness of the air bearing, extraordinary truing of the rotating shaft is built in.
And I suspect there are dozens of other applications possible. Especially as the standard bearings are very reasonably priced.