1. Assume Values for and such that their product equals

 

Gear Train Value = = = == 9.375

2. Solve the two equations for calculating the pitch diameters of the gears 1 and 2 respectively.

-------------------------- ( 1)

Center distance = --------------------- (2 )

3. Assume a reasonable module ( m):

Select a module from table (13-3) in the textbook.

4. Calculate the Number of teeth on the gear # 1 ( ):



 

This is because, the minimum number for teeth required to avoid interference for gears having a pressure angle of 20⁰ is 18.

If the condition is not satisfied, change m and recalculate the number of teeth on the gear # 1.

5. Calculate the Number of teeth on gear # 2 () :



Check for the condition that N2>18

6. Calculate the pitch line velocity () :

m/sec

7. Calculate the Tangential Force () :

N

8. Assume the Face Width of the Gear (F) :

mm

9. Calculate the Bending Stress on the gear # 1 ( ) and gear # 2 () :

 

Mpa

10. Calculate the Contact Stress on the gear # 1 () and gear # 2 () :

Note: The contact stress on each of the gears will be equal.

MPa



11. Select the Materials for the gear # 1 and gear # 2 depending upon the stress values and the Hardness values.

 

Note: Use the maximum values of the stress and go to the respective figure ( Fig. 14-2 or Fig 14-3) in the text book and select the hardness number and then from the respective table (Tab 14-3 or Tab 14-4) select the material for the gears.

12. Repeat the procedure for the second pair of gears, gear # 3 and gear # 4

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