Question

The Isthmus Slough drawbridge has an open gear reduction for the span drive. A mating pair of gears pinion E and gear Fare located about mid-way in the 5 part speed reduction. The gear teeth are un- crowned open spur gears with a pressure angle o = 20 degrees. Both gears are made to an AGMA quality level Qv = 9 and have a measured hardness of HB = 183 made from through hardened Grade 1 Steel and are un-lapped. The overload factor Ko = 1.25 for moderate impact. Pinion E is mounted on shaft X which rotates at 78.3 rpm and transmits 20 hp. Pinion E Gear F dp = 8 inches da = 30 inch Np = 16 teeth NG = 60 teeth F = 5 inches F = 5 inches Using the AGMA stress equations, calculate the tooth bending stress, o, and pitting stress Oc. Using the AGAM strength equations, calculate the bending stress safety factor SF and pitting stress safety factor SH.

Answer 1

Given Number of teeth of pinion , Np = 16 Diameter of pinion = dp = Binches lewis for face width - те - 5 inche for geca Crear, - 6o Crear, Ng dg = 3oinches Fg =5inches Sinc Same pressure angle a - 20° decid Speed of pininion Оe - 18.3 91pm) Crec Same Power = a0hp = )•qi Ku Torque of Pinion, Tp= Goxioo (Kw) Р. Nomm aan Tp = Goxlox 14.01 EST arx (783) Tp=1818390.95 Nomm Tp = 16094all Abf.inch in.mm 0.00885 ebf.incon Module m= de Zp 16 = 0.5 inches P. Given pinion and gear are mode of hardened Grade 1 Steel Ulfmate tensile strength of = 609 copsi

sut - 20,3 cops: -16 lewis from facto, y is based on no. of eth mai retai Yp - 0.295, for pinion with 16 teeth for with Goteeth, Yg = G. Hall gear Since both pinion & gear care made of The Soome materice, product (Toxy) decide the weaker of the two! clearly 'y' is less for pinion, To remaining om Same, pinion is weaker _kw Nomm Pe= a Tp de 4,023.5 Abf 1 Da I done TTX (203.2 x 78.3 Go 0183 m/sec $2.0 for velocity <com is Cai Ez .8inch 20322 20382 mm 3 134V Cu = 0.78 0885 of. incon] 320x1.7.12 Peff- to pt = 1.25 X40235[ko = 1.25 cv 0.78 ade of Pett 64 47.91 ebf mesi

Pitting a=2ng ng the 2x60 76 -1.57 r² = 1.4PE pa dp sin opeosd ta the 2 ca 4169 203 932.410 .) = 64 569-37 psi CE E == ka ore? sind cose C + 1 29897774 psi Ez sy |к K = 64.06 Sw= (Acos (dek Sw - SX 1.57X 8x 64.06 4023.4 Fos. Sw Peff