A reverted compound geartrain is needed for a marine transmi

A reverted compound gear-train is needed for a marine transmission. The gear-train has an input of 500 hp from a diesel engine at an angular speed of 1750 rpm. The desired output speed is 35 rpm.

1. Select an appropriate number of teeth for the pinion and the gears making sure undercutting is avoided.

2. Pick a value of the diametral pitch and calculate pitch diameter of the pinions and gears, calculate pitch line velocity in ft/min and tangential force for each of the stages of the train.

Table 12-8 AGMA Bending Geometry Factor for 200, Full-Depth Teeth with Tip Loading Pinion teeth 12 Gear teeth 12 U U U U U U 14 U U U U U 17 21 U U U U U U 0.24 0.24 26 U U U U U U 0.24 0.25 0.25 0.25 35 U U U U U U 0.24 0.26 0.25 0.26 0.26 0.26 55 U U U U U U 0.24 0.28 0.25 0.28 0.26 0.28 0.28 0.28 135 U U U U U U 0.24 0.29 0.25 0.29 0.26 0.29 0.28 0.29 0.29 0.29 Table 12-12 AGMA Bending Geometry Factor J for 250, Full-Depth Teeth with Tip Loading pinion teeth 12 26 135 55 Gear teeth 12 U U u U 0.28 0.28 14 17 U U 0.28 0.30 0.30 0.30 U U 0.28 0.31 0.30 0.31 0.31 0.31 21 26 u U 0.28 0.33 0.30 0.33 0.31 0.33 0.33 0.33 35 U U 0.28 0.34 0.30 0.34 0.31 0.34 0.33 0.34 0.34 0.34 55 U U 0.28 0.36 0.30 0.36 0.31 0.36 0.33 0.36 0.34 0.36 0.36 0.36 135 U U 0.28 0.38 0.30 0.38 0.31 0.38 0.33 0.38 0.34 0.38 0.36 0.38 0.38 0.38

Solution

1. from table for J = 20

to avoid undercutting we should have gear and pinion of 21 teeth

2. Take diametral pitch P = 10

P = N/PD

10 = 1750/PD, PD = 175

P = N/PD

10 = 35/PD, PD = 3.5

v = pi*d*n/6000

v = 3.14*175*1750/6000 = 160.27