Using AGMA $2001-$D$04$

Part A

A $20-$tooth pinion runs in mesh with a $70-$tooth gear.$$ The tooth form is a full depth $20$ pressure angle with a face width of $2\mathrm{.}250$ inches, and a diametral pitch of $6.$ The pinion rotates at $1750$ rpm delivering $25$ hp$.$ The gear assembly is manufactured to commercial standards, is straddle mounted between bearings, and enclosed.$$ Gear material is grade $1$ case hardened steel with a surface hardness of $50$ HRC$.$ Assuming an AGMA quality number of $10($Av$=10),$ determine the pinion and gear tooth bending stress, and minimum safety factor with respect to bending assuming $20,000$ hours of required service life with $1$ failure in $1,000$ units allowed.$$ Assume moderate shock loading.

Part B

For the gearing described in the previous example, determine the contact stress number and minimum safety factor of the gear teeth and then the pinion teeth.