Thrust bearings are used in automotive and other transportation industries. They are used in propellers, engines, centrifuges, and generators. An aviation bearing allows parts that sit close together to rotate freely with significantly reduced friction. A thrust bearing facilitates rotation around a fixed shaft or axis. Different types of thrust bearings include ball thrust, roller thrust, fluid thrust, and magnetic thrust bearings. Different types of bearings are capable of handling different loads.
The ball thrust bearing balls sit between two grooved washers inside a ring and the balls are able to move. This type of thrust bearing is useful for small axial loads. The roller thrust bearing is similar to the ball thrust bearing, however, the bearings are rollers instead of balls and they can support larger loads. There are three types of roller thrust bearings: cylindrical, tapered, and spherical. The cylindrical rollers point to the bearing’s axis; they are inexpensive but wear faster than ball thrust bearings. The tapered rollers also point to the bearing’s axis and, when used in pairs, can support axial thrust in opposite directions and assist with the radial load; they are more expensive to make. The spherical rollers are circular and asymmetrical. They support combined axial and radial loads and permit performance when axes are misaligned.
Fluid thrust bearings, or hydrodynamic bearings, contain a pressurized fluid in place of ball or roller bearings. They have low friction and wear much slower than ball and roller thrust bearings. Different types of hydrodynamic bearings that are commonly used in industrial rotating machinery include: the flatland bearing, the tapered-land bearing, and the pivoted pad thrust bearing. The flatland bearing has a small load capacity and is commonly used as a bumper for momentary load reversal. The tapered-land bearing provides a higher load carrying capability. The pivoted pad thrust bearing has the highest load capacity out of the three and is capable of adjusting to changes in operating conditions. They are used in large turbines, generators, compressors, and gearboxes. They are also used in pumps in the power generation, oil, gas, and chemical industries.
Magnetic thrust bearings contain a magnetic field in place of physical bearings. They have low drag and accommodate high speeds. There are active magnetic bearings (AMB), passive magnetic bearings, electromagnetic (EM) biased magnetic bearings, permanent magnet (PM) biased magnetic bearings, radial magnetic bearings, axial magnetic bearings, and combination radial and axial magnetic bearings. The axial magnetic bearing, or thrust bearing, produce axial support for the shaft. Magnetic thrust bearings are used in electric meters, vacuum equipment, and heart pumps.