Bearings

Types of Bearings
Some of the most common mechanical bearings are as follows

Ball Bearings - A ball bearing is essentially a hard core engineering term that is used to define a kind of roller element bearing that uses balls to maintain the separation distance between two moving objects.

High Precision Bearings - They are the kinds of bearings that allow better performances in terms of speed, system temperature stability, rigidity, accuracy and noise level which are generally not available in other simple bearings.

Needle Roller Bearings - These mechanical bearings use small cylindrical rollers to reduce friction of a rotating surface. They are known to have larger surface area in contact with the outer surface of the bearing as compared to the simple bearings.

Pillow Block Bearings - In the mechanical hardware industry, Pillow Block Bearings are referred to mounted bearings that are used extensively in conveyor systems. These bearings provide support for a rotating shaft with the mounting surface on a parallel line with the axis of the shaft.

Roller Bearings - Roller bearings are designed to carry a load by placing round elements between the two pieces in order to aid the round elements to roll with very little rolling resistance and with little sliding.

Sliding Bearings - A sliding bearing is the type of mechanical bearing that uses a lubricant to reduce friction between the sliding surfaces.

Spherical Plain Bearing - This type of mechanical bearing allows an angular rotation about a central point in two orthogonal directions to support a rotating shaft in the angular and rotational direction.

Special Purpose Bearing - Besides the regular types of bearings, various special purpose bearings too are available in the mechanical hardware industry catering to specific uses. Examples are - plastic bearings, sell deep ball bearings and high speed bearings.

Material
Bearing materials can be classified as thorough hardened materials as used in the case of ball bearings, and case hardened materials that are used extensively for roller bearings. Irrespective of the material used, the normal hardness for bearing components is 58 Rc. Alloys with various proportions of molybdenum, tungsten, chromium, vanadium, aluminum, and silicon are used to produce hardness at high temperatures. On the other hand the case hardened bearings are characterized by a hardened surface an a soft core. Since hardness decreases with increasing temperature, conventional bearing steels such as 440C and SAE 52100 cannot be used much above 350??F. The thorough hardened variety of mechanical bearing are the most commonly used material for mechanical bearings.

Applications
Mechanical bearings today are used in countless applications of everyday life. Be it rotational motion, sliding motion or angular motion, the bearings have been an important device to bring down friction in automobiles, cars and suspensions, heavy as well as light machinery. Today, the scope of ball bearings have reached up to the San Francisco airport where it is used to bear the weight of the airport. The roller element bearings in the other hand are best for high speed applications like oxygen pumps and lubricants.