The rotation of the balls causes a reduced coefficient of friction when compared with flat surfaces rubbing against each other. Because there is little surface contact between the balls and races, ball bearings typically have a lower load capacity for their size than other rolling-element bearings.

There are a variety of different designs and applications for ball bearings, and their design is specific to their industrial application and load type. Some common designs of ball bearings include:

1) Ball Bearings

Ball bearings are extremely common because they can handle both radial and thrust loads, but can only handle a small amount of weight. They are further classified into:

• Deep-Groove Ball Bearings: The most widely used roller bearing type in the world due to their versatility and overall performance. They are characterized by having deep raceway grooves in which the inner and outer rings have circular arcs of a slightly larger radius than that of the balls. They also have non-separable rings.
• Angular Contact Ball Bearings: Angular contact ball bearings can withstand high radial-axial loads and reach high speeds. They are asymmetrical for manufacturing reasons and can withstand unidirectional axial loads only. Angular bearings are usually mounted in a group of two or more opposed preloaded units with rigid or elastic spacers.
• Self-Aligning Ball Bearings: In a self-aligning bearing, the inner ring has two raceways and the outer ring has a single spherical raceway with an incenter of curvature coincident with the bearing axis. This allows the axis of the inner ring, balls, and cage to deflect around the bearing center to automatically correct misalignment caused by housing and shaft machining or installation error.

Application of Ball Bearings:

Household Items: Bicycles, Skateboards, Sewing Machines, Washing Machines, Tumble Driers, Food Processors, Hair Dryers, DVD Players, Fishing Rods.
Office Equipment: Photocopiers, Fax Machines, Hard-Drives, Fans, Air-Conditioners
Industries: Elevators, Assembly Lines, Escalators, Medical and Dental Equipment, High-speed Machine Tooling Equipment, Paper Making Machinery, Chain Saws, Power Tools, Pumps / Compressors. Toy Manufacturing, Trains, Wind Turbines.
Automotive: Engines, Steering, Driveshaft and Driveline, Electric Motors, Gear Boxes, Transmissions

2. Tapered Roller Bearings
Tapered angles allow the bearings to efficiently control a combination of radial and thrust loads. The steeper the outer ring angle, the greater ability the bearing has to handle thrust loads. To provide a true rolling motion of the rollers on the raceways, the extensions of the raceways and the tapered surfaces of the rollers come together at a common point, the apex, on the axis of rotation.

Applications: Agriculture, construction and mining equipment, sports robot combat, axle systems, gearbox, engine motors and reducers, propeller shaft, railroad axle-box, differential, wind turbines, etc.

3. Spherical Roller Bearings
A spherical roller bearing is a rolling-element bearing that permits rotation with low friction and permits angular misalignment. Typically, these bearings support a rotating shaft in the bore of the inner ring that may be misaligned with respect to the outer ring. The misalignment is possible due to the spherical internal shape of the outer ring and spherical rollers. Despite what their name may imply, spherical roller bearings are not truly spherical in shape. The rolling elements of spherical roller bearings are mainly cylindrical in shape but have a profile that makes them appear like cylinders that have been slightly over-inflated.

Applications: Gearboxes, wind turbines, continuous casting machines, material handling, pumps, mechanical fans and blowers, mining and construction equipment, pulp and paper processing equipment, marine propulsion and offshore drilling, off-road vehicles.