Question

What is the cause of backlash error?

Answer 1

Firstly, you could recall what exactly backlash error is. This could be done by thinking of the devices that get affected by this error. You may recall that this error is associated with devices that involve rotation. You could thus get the cause. Also, try to list some ways so as to avoid this error.

Complete answer:
In the question, we are asked about the cause of backlash error. In order to answer this, we need to understand what exactly backlash error is.
You may be very familiar with this error while doing experiments involving screw gauge, etc which involves turning off screws. You encounter this error while changing the direction of gears. So, when we reverse the direction of rotation of the screw, sometimes the tip of the screw doesn’t rotate immediately to the opposite direction but remains stationary for a part of rotation, this is what happens in the case of backlash error.
This error may be caused due to the various reasons. Wear and tear of the screw threads of the device and even loose fittings of the device may result in backlash error.
The one way that you can avoid this error is by taking the measurements by rotating the screw slowly only in one direction. When it is required for you to change the direction of rotation of the screw, you could stop rotating for a while and then resume the rotation in the reverse direction.
Hence, we found that this error is caused when a gap exists between the trailing face of the driving tooth and the leading face of the tooth that is behind the driven gear.

Note:
We cannot say that backlash error is completely undesirable. It may be desirable or undesirable depending on the application. Most cases it is unavoidable such as in the case of reversing of mechanical couplings. Though zero backlash is known to be the theoretical ideal condition, some backlash do help in preventing jamming.