How are the efficiencies of spur gear and helical gear compared?

How are the efficiencies of spur gear and helical gear compared?

Options:

a. efficiency of spur gear = efficiency of helical gear
b. efficiency of spur gear < efficiency of helical gear
c. efficiency of spur gear > efficiency of helical gear
d. none of the above

Correct Answer: c. efficiency of spur gear > efficiency of helical gear

Explanation:

Gears are used to transmit mechanical power from one shaft to another. Spur gears are the gears in which the teeth are parallel to the gear axis, whereas in helical gear, the teeth are not parallel to the gear axis. Because of this arrangement of teeth in helical gears, they have sliding contact between the teeth. Due to the sliding contact between the teeth of helical gear, axial trust of gear shaft also produces and also produce more heat. Thus the efficiency of helical gear is less than that of the spur gear.