What is a worm and wheel gear?

Question

Where is it used? How does it work?

Answer 1

A worm gear is a spiral thread simial to a thread on a bolt. The worm gear engages a bevel gear, as the worm gear turns its threads push the teeth of the bevel gear cauing the bevel gear to rotate.

The thread angle is such that only the worm gear may be truned to drive th larger gear. If the larger gear is attempted to be turned the teeth of teh bevel gear just jame against the worm gear keeping the larger gear locked in position.

This means that a worm gear only lets power flow in one direction from the worm to the gear but not the other way around.

Also note that the angles of the shafts between the two gears are at 90 degrees.

Answer 2

A worm gear is a gear that sort of looks like a spiral, and as a gear turns, it pushes the worm gear, turning it. Even thought this gives it more torque or something, it may slip or grind. This would make much friction. For more info, go to http://www.usfirst.org/
hold the cursor over "team resources", and click on "Building"
go to the highlighted "The Art of LEGO Design by Fred Martin" and click on it. scroll down, and there will be an explanation and pictures.