Getting to grips with Ball Bearings

It's often hard to believe that something so small and simple such as a ball bearing has so much of an effect and impact on the way in which pieces of machinery operate. They are in fact found within most of the items that a lot of us use, we just don't realise it. They are used as a means of reducing friction that occurs between shafts and axles in a number of applications. In most cases they are used in a series as a way of absorbing the weight that is placed on a moving part or within individual cages in order to reduce friction within axle assemblies.

The bearings that are used in a lot of applications are either small metallic or small ceramic spheres. They are precision made as a means of meeting the exact standards of roundness. This is of high importance as any deformation can cause the moving parts to fail unexpectedly. Also to ensure that no pieces of machinery that use ball bearings do fail unexpectedly there are a number of bearings available to ensure that whatever they are needed for they are able to do their job correctly. For example plain bearings are widely used, especially within applications that involve surfaces that have rubbing contact. Another example comes in the form of a low friction bearing, which is important for efficiency and as a means of reducing wear so that the application it is used in can still operate at high speeds. These bearings are highly impressive due to the fact they can reduce friction by their shape and the material that they are made out of as well as by introducing a fluid between the surfaces.

This is a device that is able to allow constrained but relative motion between two or more parts; this is typically rotation or linear movement. It is also through movement such as this that bearings may be classified as well as their principle of operation and the direction of applied loads that they can handle. This brings me onto my next point, which is all about how they are classified when it comes to combating friction:

• By shape - This gains the bearing an advantage.
• By material - This exploits the nature of the bearing material used.
• By fluid - This exploits the low viscosity of a layer of fluid, such as a lubricant or as a pressurized medium to keep the two solid parts from touching, or by reducing the normal force between them.
• By fields - This exploits electromagnetic fields, such as magnetic fields, to keep solid parts from touching.

In some cases ball bearings may even contain a combination of the above. An example of this is where the cage is made of plastic, and it separates the rollers/balls, which reduce friction by their shape and finish.

Without bearings aspects of our life would become incredibly complicated. This is why they are such a much needed aspect to many of the applications that we use in our everyday lives.