Bearings are often found in machines. As their name suggests, they are designed to “bear” the weight or force of a part. Machines often have multiple moving parts. Bearings can restrain the motion of these parts while also reducing friction between them.
Ball bearings are those that that feature a set of balls. They can support radial forces as well as thrust forces. When exposed to a force, the balls will roll to reduce friction. Ball bearings are often preferred over other types of bearings because of their ability to reduce friction. Some ball bearings contain just four or five balls whereas others contain over a dozen balls. Regardless, all ball bearings use balls to reduce friction.
Roller bearings aren’t the same as ball bearings. Roller bearings involve the use of balls within races. Races are rings that are designed to support the balls. Ball bearings that feature races are known as roller bearings. They feature races that contain the balls.
Magnetic bearings, of course, are characterized by the use of a magnetic field. They leverage a magnetic field to constrain the movement of a part. You can find magnetic bearings in centrifugal compressors, medical devices, electricity monitoring meters and more. They don’t use a mechanical method of operation. Rather, magnetic bearings work by producing a magnetic field — meaning they don’t move during use.
Another common type of bearing is flexure. Flexure bearings are those that allow for a limited the angle of rotation or movement. They typically consist of two structures that are connected together by a hinge. Lids, for instance, may consist of a flexure bearing. Flexure is a simple, common type of bearing that allows for a limited angle or rotation or movement.
There are also fluid bearings. Fluid bearings are characterized by the use of a fluid, such as an oil or lubricant. They feature bearing surfaces. Between these bearing surfaces is a thin layer of fluid. The fluid acts s a lubricant while allowing the bearing surfaces to move.
Fluid bearings may further be classified as either hydrostatic or fluid dynamic. Hydrostatic bearings feature a passage through which fluid is pumped. Fluid-dynamic, on the other hand, suction fluid from around the shaft. Regardless, they both feature a thin layer of fluid between their respective bearing surfaces.