Question

a) List four (4) advantages that helical gears have when compared to spur gears.

b) List four (4) disadvantages that helical gears have when compared to spur gears.

Answer 1

a) Advantages of Helical Gears

1. Gradual Engagement of Mating Gears due to which there is no impact loading also the operation is noiseless

2. Used for High Power transmissions

3. Helical Gears with some modifications can be used for nonparallel or intersecting shafts such as crossed helical Gears.

4. The higher number of teeth leads to load distributed over thus less wear

b) Disadvantages of Helical Gear

1. Manufacturing of Helical Gears is more complex than spur gears due to angled teeth

2. Axial Thrust in Helical gears put extra load on bearing. This thrust is absent in spur gears

3. Efficiency is also less for Helical Gears because of Sliding contact causes loss of power in form of Heat

4. Overall Cost of Helical Gaer Drive is high. Thus wherever possible like in low power transmission mechanisms like Toys spur gears are used.