Question

Figure Q1 shows a gear train consists of four spur gears A, B, C and D to be designed for a specific mechanism. The power transmitted by gear A is 5 kW at rotational speed of 720 rpm counterclockwise direction. Number of teeth (N) for gears A,B,C and D are respectively 20, 50, 30 and 60. The module and pressure angle of the gears are respectively 4 mm and 20o . Determine followings: (a) Tangential and radial forces between gears A and B and gears Cand D. (b) Torque and output power transmitted at gear D.  (c) Draw the free body diagram of forces

Helical gears were selected to design the gear train shown in Figure Q1 instead of the spur gears. The power transmitted by gear A is 10 kW at rotational speed of 720 rpm counterclockwise direction. Number of teeth (N) for gears A, B, C and D are respectively 20, 50, 20 and 60. Pressure angle (∅)for all the gears is 20o . Helix angle (𝜓) and module (m) for gears (A and B) are 30o and 3 mm respectively. While the helix angle and module for gears (C and D) are 25o and 5 mm respectively. A has right-handed helical teeth, while the pinion C has left-handed helical teeth. Shaft 2 is supported by two bearings B1 and B2, where the bearing B1 can take the radial load, while the bearing B2 can take both radial and thrust load. Determine the followings: (a) The forces on gears B and C. (b) The bearing reactions (of the bearings B1 and B2) on shaft no. 2. Illustrate your answer with sketch drawing.

Answer 1