What is the advantage/s of worm and worm wheel?

What is the advantage/s of worm and worm wheel?

Options:

a. low power losses
b. do not produce heat
c. high velocity ratio can be obtained in a single step
d. all of the above

Correct Answer: c. high velocity ratio can be obtained in a single step

Explanation:

Worm and worm wheel are special type of gears which are used to transmit torque when driving shaft and driven shaft are non-intersecting to each other. Worm corresponds to screw and worm wheel is similar like spur gear.



Worm and worm wheel is simple way to achieve high torque. It operates smoothly and silently and is self locking. Due to frictional contact between worm and worm wheel it produces a lot of heat. There is far more difference between speeds of worm and worm wheel due to which high velocity ratio of the order of 100 can be obtained. Thus it loses more power.