Question

A road grader has 36" diameter wheels which are driven by a two-stage planetary gear train as shown below. All gears have 20 teeth except for the fixed ring gear which has 60 teeth. If the road speed of the grader is to be 20 mph, calculate the required rotational speeds of the output shaft and input shaft. Determine the overall input to output ratio. Input Output 20 mph Note, choose one or more than one of the following MC answers and then type the letter (s) corresponding to the question number in the essay section of this problem with supporting calculations contained on the scratch sheet. If the answer requires "the correct answer is type that in the essay section as well. 11

Answer 1

Important thing to notice here is that wheel (output) is connected to arm gear of second gear box ( the one which is located relatively outside in the image). And prime mover (engine) is connected to sun gear of first gearbox(the one which is located relatively inside in the image )

Now further analysis is performed in the images below ::

رفع میک fict Il shaft outfiy shaft Planet Gears Arng hing Gear (0 Te) v=20 mph Koneet 18 inch م 0,955 18 - جودي, میر - لری from Diagram it is clear that (( همه و هو. = 1 : پی ہے و حجم ششم : نتعر) - د E د ننني لا ج -2 - حکم -وه 3 زو - ! (طار نے نور که به هم زد دورة إدارد 토 Planet Rina * ( ) = از * و جذش = 7 (2) * وزیر وہ جو لن من عین خوش من director of Por (ra) hotx- hix 증한 Moring

Caring +7 —.. ) ha=r Asume Wamma H = 4 1) К (32) + 2 = rad 19. в Woent a = К .. Wasma rool 78. 4 О. sung 4 [ 19. b) = *18 s

Drung . broce brot Arma "second year system final gear is exactly Same as Previous Ratis Will Also be one its - Same t. Similes to eq D Weun, 4 Warm, mo 1 broe 4 X 78.4 forow 9.ElE Wamput Wsmi sum,
So overall gear ratio becomes 4*4 = 16.

For the third part of this question option (a) and (d) can be used. As in first case u are increasing the gear ratio itself , and in the second case you are increasing radius of the wheel so that even by smaller angular speed you'll get more linear speed.

Hope you got the concept well..!!!