Ball bearings- are probably the most common kind of bearing. They are found in everything from inline skates to hard drives. These bearings can handle both radial and thrust loads, and are commonly found in applications where the load is relatively small. In a ball bearing, the load is transmitted from the outer race to the ball and from the ball to the inner race. Since the ball is a sphere, it only contacts the inner and outer race at a very small point, which helps it spin very smoothly. But it also means that there is not very much contact are holding that load, so if the bearing is overloaded, the balls can deform or squish, smashing the bearing.

Roller bearings- widely used in applications like conveyer belt rollers, where they must grip heavy radial loads. In these bearings, the roller is a cylinder, so the contact between the inner and outer race is not a point but a line. This spreads the load out over a larger area, allowing the bearing to handle much higher loads than a ball bearing. However, this kind of bearing is not designed to handle much thrust loading.

Tapered roller bearing- are capable of supporting large radial and large thrust loads. Tapered roller bearings are widely used in car hubs, where they are usually mounted in pairs facing opposite directions so that they can handle thrust in both directions. In many applications tapered roller bearings are used in back to back pairs so that axial forces can be supported equally in either direction.

Needle roller bearing- is a bearing which uses small cylindrical rollers. They are used to minimize friction of a rotating surface. Needle bearings are heavily used in engine components such as rocker arm pivots, pumps, compressors, and transmissions.

Spherical bearing- widely used in many applications, wherever rotational motion must be allowed to change the alignment of its rotation axis. A spherical bearing is a bearing that permits angular rotation about a central point in two orthogonal directions. Spherical bearings are used in automobile suspensions, engines, drive shafts, heavy machinery, sewing machines, and many other applications.

Fluid bearings- are bearings which support the bearing loads solely on a thin layer of liquid or gas. Fluid bearings are usually used in high load, high speed or high precision applications where ordinary ball bearings would have a short life or cause high noise and vibration. Fluid bearings are usually quieter and more smoothly than rolling element bearings.

Jewel bearing- mainly applied to low-load, high precision work such as clocks. Where their low andPredictable friction enhances watch accuracy as well as improving bearing life. Jewel bearings may bevery small. The other major usage of jewel bearings is insensitive measuring instruments.

Thrust ball bearings

Ball thrust bearings like the one shown to the left are mostly used for low-speed non precision applications. They cannot take much radial load and are usually found in lazy Susan turntables and low precision farm equipment.

Roller thrust bearing

Roller thrust bearings like the one illustrated to the left can support very large thrust loads. They are often found in gear sets like car transmissions between gear sprockets, and between the housing and the rotating shafts. The helical gears used in most transmissions have angled teeth; this can causes a high thrust load that must be supported by this type of bearing.

Bearing Loads

Bearings typically have to deal with two kinds of loading, radial and thrust. Depending on where the bearing is being used, it may see all radial loading, all thrust loading or a combination of both.

The bearings in the motor and the pulley pictured above face only a radial load. In this case, most of the load comes from the tension in the belt connecting the two pulleys.

The bearings in this stool are subject to a thrust load.

The bearing above is like the one in a barstool. It is loaded purely in thrust, and the entire load comes from the weight of the person sitting on the stool.

The bearings in a car wheel are subject to both thrust and radial loads.

The bearing above is like the one in the hub of your car wheel. This bearing has to support both a radial load and a thrust load. The radial load comes from the weight of the car; the thrust load comes from the cornering forces when you go around a turn.