Helical Gears

Helical Gears

Helical Gears - A helical gear is just like a spur gear but with its teeth at an angle with the axis of rotation of the gear body. Helical gears can transmit motion from one shaft to another shaft that is parallel with it, as with spur gears, and also to another shaft that is not parallel to it. Helical gears operate more quietly and smoothly than spur gears. This is due to the fact that teeth of helical gears slide one across the other rather than hitting each other as in spur gears.

Moreover, unlike spur gears, in helical gears several teeth of each gear are in contact at one time and thus the load is spread, resulting in greater strength than if only one tooth of each gear is in contact at a time as in spur gears, However, in helical gears, the friction, heat generated and wear is high because of the sliding action of one tooth on another.

Therefore helical gears should run in oil bath as in automobile transmission. Another disadvantage with helical gearing is that helical gears exert an end thrust which must be absorbed by a thrust bearing.