Component Design
20-mm diameter solid round shaft
Pump Housing
200-mm diameter gear
Figure 1.0
Figure 1.0 shows a portion of a mechanical system at a uniform load and constant speed of 600 rev/min. The system has a 200 mm diameter helical spur gear that is mounted on the overhung end of a shaft, 180 mm from the nearest bearing. The AISI 4340 HR shaft is supported by bearings mounted in the pump housing. The loads acting on the gear are Fax = 1400 N, Fay = 2000 N, and Faz = 1200 N. Experienced engineers suggest that the safety factor of the shaft is 2.0. Use Distortion Energy Theory.
1.1
Sketch the free body diagrams for the gear and the shaft using isometric projection. Label the diagrams properly and provide the values for all the action and reaction loads.
1.2
Draw the shear force, the bending moment, and torsion diagram for the shaft. Label the diagrams properly and provide the values at key points.
1.3
Draw the element stress at the critical point of the shaft and compute the stresses developed. Indicate clearly the direction of the stresses.
1.4
Will the shaft survive under these static loadings? Prove it.
1.5
You have drawn the shear force diagram in part 1.2, but what are your justifications for not including the transverse shear stress in your calculations in part 1.3?