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Bearings – The Definition and Classification:

written by: kkaarthic • edited by: Lamar Stonecypher • updated: 7/27/2009

This article is about bearings - how they are to be defined and what are the various classifications best known to us. This series of article will enlighten you more about bearings.

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    What are Bearings?

    Bearings are indispensable machine elements finding utility in almost all the gadgets what we use in our day to day life right from our the electric shavers to the cars we drive. Just think of anything that rotates and you are sure to find a bearing in one form or other in it. Well here’s my definition of what a bearing is:

    As the name suggests “Bearing” is something that bears up the loads and yet rotates. It holds on to a rotating member firmly leaving no way for it to move around or in right terms it holds something tight in its place fit and tight.

    In real engineering terms a bearing is defined something like this “ Any two surfaces rubbing against each other be it a bush or sleeve around a shaft or a flat surface moving over an other flat surface can be termed as a bearing.”

    Let me first list down the uses or to put it rightly the advantages of bearings as a whole.

    1. They assist in easy rotary action thereby reducing the effort or power required. Just think about your pulling your vacuum cleaner around the home without any wheels or without any bearings to the wheels.
    2. They assist in carrying loads or assist in transferring the loads from something that tends to rotate to something which is stationary and has the capability to carry the loads. Just visualize the giant wheel that rotates on bearings, the complete weight of us along with the weight of the giant wheel is transferred to the stationery holding structure of the giant wheel by the bearings.

    But there is one important aspect which has to be cared for, “Lubrication” without which the bearings will not be able to perform the above mentioned duties at the best. We will look into more detail on the lubrication aspects of the bearings in the forthcoming articles.

    Well we will now look into the classification of the bearings. They can be basically classified as

    1. Hydrodynamic Bearings
    2. Hydrostatic Bearings
    3. Rolling Element Bearings

    Hydrodynamic and Hydrostatic Bearings are those which we design and manufacture all by ourselves for the majority cases. These are more specific to the application, costlier in budget but work really effectively.

    Rolling Element Bearings are those which are readily available catalogued products in the market. They are surely cost effective; just select them from the catalogue based on the requirement. Very rarely are rolling element bearings designed and manufactured.

    Although the bearings are classified into these three types the varieties each type of bearing holds is enormous. The forthcoming articles will deal more with these details.