# Ch:29 Gearbox¶

## exa 29-1 - Page 749¶

In :
from __future__ import division
from math import sqrt, pi
Ts1=16#
Ts2=18#
Ts3=20#
Ts4=25#
Tr1=64#
Tr2=63#
Tr3=70#
Tr4=50#
#Let Nr1/Nr2=G1
G1=1+(Ts1/Tr1)#
#Let Nr1/Ni=G2
G2=(Ts2/(Tr2*(1-(1/G1)+(Ts2/Tr2))))#
#Let Ni/No=G3 (third gear)
G3=(1+(Ts3/Tr3))/((Ts3/Tr3)+G2)#

#Let Ni/Nr1=G4
#The ratio calculations are done as above
G4=1.2857/0.2857#
#Let Ni/No =G5(second gear)
G5=-20/70#
#Let Ni/No=G6(first gear)
G6=1.2857/0.2857#
#Let Ni/No=G7(reverse gear)
G7=-1.7143/0.2857#
print "ratio for third gear is %0.3f    "%(G3)#
print "\nratio for second gear is %0.4f   "%(G5)#
print "\nratio for first gear is %0.1f   "%(G6)#
print "\nratio for reverse gear is %0.3f   "%(G7)#


ratio for third gear is 1.471

ratio for second gear is -0.2857

ratio for first gear is 4.5

ratio for reverse gear is -6.000


## exa 29-2 - Page 751¶

In :
#Let reverse speed gear be RSG
RSG=5.5#
#Let T5/T6 = Z1
T1=2#
#Let T3/T7 = Z2
Z2=2.75#
T7=18#
T3=Z2*T7#
T3=50#
#Let T3/T1 =Z3
Z3=2.5#
T1=T3/Z3#
#Let T4/T2 = Z4
Z4=2.25/2#
T2=(T1+T3)/(Z4+1)#
T4=T1+T3-T2#
#Let T5/T6=Z5
Z5=2#
T6=(T1+T3)/3#
T5=(T1+T3)-T6#
T7=18#
#let first gear ratio is G1
G1=50*47/(20*23)#

#Let 2nd gear ratio is G2
G2=37*47/(33*23)#
#Let 3rd gear ratio is G3
G3=1#
#Let reverse gear ratio is R
R=50*47/(18*23)#
print "T1 is %0.0f    "%(T1)#
print "\nT2 is %0.0f    "%(T2)#
print "\nT3 is %0.0f    "%(T3)#
print "\nT4 is %0.0f    "%(T4)#
print "\nT5 is %0.0f    "%(T5)#
print "\nT6 is %0.0f    "%(T6)#
print "\nT7 is %0.0f    "%(T7)#
print "\nG1 is %0.3f    "%(G1)#
print "\nG2 is %0.3f    "%(G2)#
print "\nG3 is %0.1f    "%(G3)#
print "\nR is %0.3f    "%(R)#


T1 is 20

T2 is 33

T3 is 50

T4 is 37

T5 is 47

T6 is 23

T7 is 18

G1 is 5.109

G2 is 2.291

G3 is 1.0

R is 5.676


## exa 29-3 - Page 752¶

In :
#Let the constant gear ratio be G
G=2#
x=5.5**(1/3)#
G1=1#
G2=x#
G3=x*x#
G4=x**3#
T7=18#
T8=T7*(x**3)/2#
T8=51#
T5=69/2.558#
T6=69-27#
T4=69/1.8825#
T3=69-T4#
T1=23#
T2=46#
T9=18#
G1=T2*T8/(T1*T7)#
G2=T2*T6/(T1*T5)#
G3=1#
G4=-T2*T8/(T1*T9)#
print "T1 is %0.0f    "%(T1)#
print "\nT2 is %0.0f    "%(T2)#
print "\nT3 is %0.0f    "%(T3)#
print "\nT4 is %0.0f    "%(T4)#
print "\nT5 is %0.0f    "%(T5)#
print "\nT6 is %0.0f    "%(T6)#
print "\nT7 is %0.0f    "%(T7)#
print "\nT8 is %0.0f    "%(T8)#
print "\nT9 is %0.0f    "%(T9)#
print "\nG1 is %0.3f    "%(G1)#
print "\nG2 is %0.3f    "%(G2)#
print "\nG3 is %0.3f    "%(G3)#
print "\nG4 is %0.3f    "%(G4)#

T1 is 23

T2 is 46

T3 is 32

T4 is 37

T5 is 27

T6 is 42

T7 is 18

T8 is 51

T9 is 18

G1 is 5.667

G2 is 3.114

G3 is 1.000

G4 is -5.667