Machine Design - II (ME 308 Lab)

Shaft Design - Project # 1

Term 991

Steps # 1 & 2

  1. Using the following equation, calculate input torque:
  2. N.m. where:

    P is power in kW

    n is shaft speed in rpm


  3. Draw the torque diagrams for both shafts based upon these value of T

  5. Calculate transmitted load between the gears:
  6. where:

    P is power (kW)

    n t is pitch line velocity = 3.37 m/sec.


  7. Calculate the normal force between the gears:
  8. where:

    Wt is the transmitted load (N.)

    f is the pressure angle of the gears = 20


  9. Perform a complete force analysis on the shafts in the y and z directions to determine the resultant reactions at all 4 bearing locations:
  10. Resultant reaction is given by


  11. Using equation (11-9) from the text book, calculate the rated force for each bearing:

    Use Eqn. (11-9)



    FR is the Catalog Load Rating

    FD is the Design Load*

    LD is the Design Life in Hours = 20000 Hrs.

    nD is the Design Speed (given in rpm)

    LRnR is the Rated Life = 106 rev.

    R is the Reliability = 95%

    a for Ball Bearings = 3

    * for the values of FD, use the values of the resultant reactions calculated for all 4 locations in step 5 of the lab-sheet

  13. To calculate C, use the following equation:
  14. C=A.F. FR


    A.F. is the Load-Application Factor - use table (11-6)


  15. Select Deep Groove Ball Bearings for all 4 bearing locations on the shaft using table (11-3). Use the value of C, calculated above to select the bearing and note down all bearing data




  1. Draw the shear force and bending moment diagrams in the y and z directions and the resultant bending moment diagram with a free hand sketch of each shaft