Worm gear

Hi all,
Is there anyone who is kind enough to answer me?

The Worm and Worm Gear consists of two parts , namely the Worm Screw ie the rotating Screw which meshes into the Worm GEar wheel which is a Spur Gear.

The principle is that , for one rotation (360 deg) of the Worm Screw the Worm Gear ( wheel ) moves by one Tooth .

In the Worm and Worm pair, the driving shaft is attatched to the Worm screw and the driven shaft to the gear wheel.

From the above principle of motion, it is clear that the SpeedReduction in this pair is very high as for one rotation of the screw the gear turns only for one tooth.

The gear ratio for a Worm and Worm wheel pair is always : Size of the Worm Gear : 1, because the gear turns only for one tooth for one rotation of the screw.

Thus Worm and Worm gears are used to get very LOW SPEEDS and transmit HIGHER TORQUE at the same time and at same low speeds. The Worm and Worm assembly is very compact as compared to other type of gearing used.

Due to the compactness and comparitive Size to Reduction Ratio relation they are mostly preffered for very Low speed generations and high torque requirements at low speeds.
Such as some differentials, in mechanical metal presses, conveyers etc.

The main relation of motion between the two elements is mentioned above. The Load and the reduction ratio required will dictate the Module of the gear and the pitch. All other parameters and the Derivation required can be accordingly found out from any standard text book.