Answer Happy

1. Gear train design (10) (a) Design a simple two gear train with velocity ratio my = wout/Win = -1/8, and a diametral pitch of 12. Specify the pitch diameters and the number of teeth, and calculate the contact ratio mp. Assume a pressure angle of 20°. With all things remaining the same, will the contact ratio increase or decrease if you had a pressure angle of 25°. Check your prediction by recalculating the length of action Z and then my (b) Design a simple gear train to have a velocity ratio of 1/81. Next design a compound gear train for the same velocity ratio. For each design you must keep the gear ratio between pairs to no more than 10:1 and draw the front view and top view with cylindrical discs representing the years to an approximate scale with the first driving gear the same size. Also, specify the number of teeth in each gear assuming that the first driving gear will have 17 teeth. Which one out of the two designs simple and compound gear train-is more compact?