What is backlash and why is it a problem?

Many components are spaced out to ensure that contact surfaces do not touch. This may be to allow for lubrication or thermal expansion, or it could be down to manufacturing tolerances or deflection under load. This spacing of components can cause backlash within the application.

Backlash occurs when a force is applied to a component as a result of the movement of another component. This can be seen in action when a train changes direction: the carriages shake and you hear clattering noises.

Even systems which are described as zero-backlash are likely to have a small amount of backlash. However, this is often so small that it doesn’t affect the application.

Precision applications such as robotics and servo applications need a high level of accuracy, so any lost motion caused by backlash is a problem.

Backlash is commonly associated with couplings. This is because backlash can accumulate in couplings as the joining piece for components. By selecting a backlash free coupling, the effects of backlash can be minimised within the system.

If you need assistance with minimising backlash in your application, contact our dedicated couplings division. 

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