It is required to design a pair of spur gears with 20° full-depth involute teeth
based on the Lewis equation. The velocity factor is to be used to account
for dynamic load. The pinion shaft is connected to a 10 kW, 1440 rpm
motor. The starting torque of the motor is 150% of the rated torque. The
speed reduction is 4 : 1. The pinion as well as the gear is made of plain
carbon steel 40C8 (� = 600 �/��2). The factor of safety can be taken
as 1.5. Design the gears, specify their dimensions and suggest suitable
surface hardness for the gears.