INA Bearings

WHAT ARE BEARINGS

 

 

Common motions permitted by bearings are:

·                    Axial rotation e.g. shaft rotation

·                    Linear motion e.g. drawer

·                    spherical rotation e.g. ball and socket joint

·                    hinge motion e.g. door, elbow, knee

 

Reducing friction in bearings is important to reduce wear and to facilitate extended use at high speeds and also to avoid overheating. A bearing can

reduce friction by virtue of its shape, material component (plastics that have low surface friction) or by introducing a fluid or electromagnetic field between surfaces.

 

Speeds

Plain bearings only handle lower speeds, rolling element bearings are faster, followed by fluid bearings and finally magnetic bearings which are limited by centripetal force overcoming material strength.

 

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Plain bearings use surfaces in rubbing contact, often with a lubricant such as oil or graphite. A plain bearing may or may not be a discrete device. It may be nothing more than the bearing surface of a hole with a shaft passing through it, or of a planar surface that bears another (in these cases, not a discrete device); or it may be a layer of bearing metal either fused to the substrate (semi-discrete) or in the form of a separable sleeve (discrete). With suitable lubrication, plain bearings often give entirely acceptable accuracy, life, and friction at minimal cost. Therefore, they are very widely used.

However, there are many applications where a more suitable bearing can improve efficiency, accuracy, service intervals, reliability, speed of operation, size, weight, and costs of purchasing and operating machinery.

Thus, there are many types of bearings, with varying shape, material, lubrication, principle of operation, and so on. For example, rolling-element bearings use spheres or drums rolling between the parts to reduce friction; reduced friction allows tighter tolerances and thus higher precision than a plain bearing, and reduced wear extends the time over which the machine stays accurate. Plain bearings are commonly made of varying types of metal or plastic depending on the load, how corrosive or dirty the environment is, and so on. In addition, bearing friction and life may be altered dramatically by the type and application of lubricants. For example, a lubricant may improve bearing friction and life, but for food processing a bearing may be lubricated by an inferior food-safe lubricant to avoid food contamination; in other situations a bearing may be run without lubricant because continuous lubrication is not feasible, and lubricants attract dirt that damages the bearings.

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