- Question 5 20 Marks A 24 Tooth Pinion With A Diametral Pitch Of 6 Teeth Per Inch Drives A 60 Tooth Gear In A High Prec 1 (211.13 KiB) Viewed 19 times
Question 5 (20 Marks) A 24-tooth pinion with a diametral pitch of 6 teeth per inch drives a 60-tooth gear in a high precision machine. The gears have face width of 3 inches and a pressure angle of 20 degree. Pinion is fabricated from AISI 4340 steel (S. = 108 ksi, Sy = 68 ksi, and Brinell hardness number Hp=217); while gear is fabricated from AISI 4130 steel (Su = 81 ksi, Sy 52 ksi, and Brinell hardness number Hø= 156). = If the gear set operates at a constant pitch line velocity of 1000 feet per minute, using a reliability of 99% and a safety factor of 3, estimate the maximum allowable horsepower that can be transmitted for infinite fatigue life, based on the following conditions: (a) gear tooth bending fatigue failure; and (b) gear tooth surface fatigue failure. Assume i). The source of power is uniform and there is a moderate shock in the machine. ii). The mountings are accurate. iii). There is no load sharing between the gear teeth.