Quote:
Originally Posted by MichaelBick
192 ran worm gears and did not have any problems from what I heard. They have the nice benefit of giving you more space in the center of your robot.
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They also used 4 lead worms for increased efficiency, which made them backdrivable. This let them coast to stops, and even theoretically get pushed
The other thing to keep in mind about worm gears is that most of their non-back drivability (even for 1 lead worms) comes from when they're stopped. When they're stopped, you've got a ton of force pushing the worm gear's teeth into the worm (if the output's under load), and because of the angle of the contact between the teeth, it usually can't slip. However, when the tooth surfaces are turning relative to each other, you're dealing with kinetic sliding friction, which is a lot less. You'll actually see the output pushing the input a bit when some worm gearboxes aren't under power, but moving. Because they no longer have to deal with the huge static coeficient of friction, they become essentially temporarily backdrivable. This means that worm gearboxes can coast for a little while, especially when they've got a fair amount of force on the output.