Hello, when open up a servo gear train (eg. MG996R) the drive gear always has a stopper knob. I am not sure what its exact function. It seems to do more harm than good because when servo rotation exceeds a bit, the stopper knob will crash into the driving gear, chip the teeth. I yelled out the knob, it works just fine and not has to worry the gear chipping. What is the knob for? Thanks.
The stopper mechanically limits the rotation of the servo. The position of a servo is determined by feedback from a potentiometer, but there will be a tolerance on that. I am guessing a bit but I suppose the idea of the stopper is to ensure that a 180deg servo cannot move more than 180deg because there could be consequences for attached mechanisms.
What is the knob for?
To prevent damage to your expensive RC model
You cannot turn the feedback pot through a full 360, so that pin prevents damage to the pot by limiting travel.