1. A spur gear made of bronze drives a mid steel pinion with angular velocity ratio of 13 /2 : 1. Thepressure angle is 14 1/2° . It transmits 5 kW at 1800 r.p.m. of pinion. Considering only strength, design the smallest diameter gears and find also necessary face width. The number of teeth should not be less than 15 teeth on either gear. The elastic strength of bronze may be taken as 84 MPa and of steel as 105 MPa. Lewis factor for 14 1/2° pressure angle may be taken as y =0.6840.124 –No. of teeth.
