Timing Belt and Pulley Backlash Reduction

Reducing pulley backlash and Increasing positioning accuracy has a two-part approach. Timing belts and pulleys working together will help you achieve reduced or zero backlash with optimal belt stiffness and accuracy.

What is Backlash?

Backlash in a timing belt drive is caused from the tiny space left when a timing belt tooth engages with the pulley tooth gap. This space is normal but it can cause a tiny bit of "play" when the belt stops or changes direction. In most applications, this is acceptable. However, in the case of very high precision applications such as linear drives with precise positioning, any amount of backlash could prove to be too much. The solution is to Increase positional accuracy by reducing play at the pulley tooth gaps.

How to Reduce Backlash

• The first thing you want to do it make sure you are using the correct tooth profile. Trapezoidal teeth such as the T-series and AT-series have less backlash than HDT belts and are better suited to the task.
• You want to choose a belt for its stiffness. AT-series timing belts have high strength tension members with increased spring-rate for better repeatability and reduced settling time. A timing belts such as move-series offers 75% greater stiffness than traditional AT timing belts.
• Select a timing pulley with reduced "SE" or zero "0" backlash

Pulleys with Reduced or Zero Backlash

As you can see from the chart below, there are three types of backlash. Normal backlash is the standard for all pulleys and that is what BRECOflex provides, unless otherwise specified. Reduced "SE" backlash eliminates most of the "play" but is not available for all pulley sizes. Zero "0" backlash is the best option if you want the most accuracy and is available in many T and AT pitches.

Pulley backlash options are available as follows:

Timing Belt Stiffness

When designing a linear drive, belt stiffness is one of the most important parameters in determining the level of accuracy.  The chart below demonstrates the specific stiffness of move-series compared to other pitches. When used with zero backlash pulleys you will achieve the highest possible accuracy.

If you need to increase accuracy, reducing backlash and increasing belts stiffness is the way to go. As a single source supplier, BRECOflex can offer a two-part solution by combining the stiffest high precision timing belts with zero backlash pulleys that are made to mesh perfectly. Timing belts for linear drive are in stock and available in any length. Zero backlash pulleys are made-to-order with quick turnaround. Contact us for more information.

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