Question

2. Consider the triple speed reduction gear box shown in Figure 1. All the gears are made with a diametral pitch of 16 in. The input of the gear train is gear A, and the output is gear G. The gear train transmits an input toque of 250 lb-in, at a speed of 2,500 rpm clockwise. The number of teeth on each gear is given as follows: NA 24 teeth, Na = 60 teeth, Nc 20 teeth, No 58 teeth, Ng=21 teeth, Np 35 teeth, Ng 63 teeth. (20 marks) a) Determine the train value, the output speed, and the output rotation direction. b) Determine the output torque of the gear train c) Determine the pitch line velocity of gear G. d) Given a diameter of 1.5 in for the shaft that carries gear G, design the key length to transmit the torque. The width of the hub of gear G is 1.5 in. Assume the key is made from SAE 1018 steel (S,-54 ksi) and is weaker than the gear and shaft materials. Use a design factor of 3. e) Can the key designed in part d carry the given torque? If not, determine the required key material yield strength, assuming the length of the key is equal to the width of the hub of gear G. G E F E A Figure 1: Triple speed reduction gear box for question 2 m

Answer 1

Tin 2250 Ab-の Sa e 250D p NA=24, No60、Ne 20,Nり2 58 NE 21, NF235, N63 Specal Palio (SR) NDriven cve Don NDAVE Train Value SR Noriven NAX Ne xNE Tran yalue NBXNOX G NF has not bren consiolere o idller gear it's because aan 24x20 21 Train value GexS8 3 2 (74

Sa 2 250 D wde 2XAX 2 500 60 2618 Power 0/P Power iP WA To/P Typx 2 Noxve NBven Wpmen Tcun ralue Pmve 8 174 12. 036 ad/s S437. S b -in 250 x 74 Pitch ne velo uity af GearG Ds xCoG 2 23.7 ms V 2 X 2 174 OA 16 in Diametmeal Pitch 16 2 NG 7 徳63 12

2230TL 54 ksi S1 27 hsi 2 2 FOs 3 Consiclenhg (Tyafe 9 ksi 27 3 lenyth hey 2 1.5in of hey b wicth 9 Y X2 fshear 2 Fx da To/P S437.S X 2 20.537 in