ME - 308 : PROJECT # 2

Design of a Speed Increasing Gear Train

Given Data

Power = 10 KW

Input speed ( n_{1} ) = 900 rpm

Gear Train Value ( n_{4} \ n_{1} ) = 9.375

STEP # 1 : Gear Design

- Assume Values for and such that their product equals
- Solve the two equations for calculating the pitch diameters of the gears 1 and 2 respectively.
- Assume a reasonable module ( m):
- Calculate the Number of teeth on the gear # 1 ( ):
- Calculate the Number of teeth on gear # 2 () :
- Calculate the pitch line velocity () :
- Calculate the Tangential Force () :
- Assume the Face Width of the Gear (F) :
- Calculate the Bending Stress on the gear # 1 ( ) and gear # 2 () :
- Calculate the Contact Stress on the gear # 1 () and gear # 2 () :
- Select the Materials for the gear # 1 and gear # 2 depending upon the stress values and the Hardness values.
- Repeat the procedure for the second pair of gears, gear # 3 and gear # 4

Gear Train Value = = = == 9.375

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

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

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

This is because, the minimum number for teeth required to avoid interference for gears
having a pressure angle of 20^{0} is 18.

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

Check for the condition that N2>18

m/sec

N

mm

Mpa

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

MPa

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.