# Chapter11-Gear Design¶

## Ex1-pg217¶

In [1]:
import math

print('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.1 Page No.217\n');

N2=60.;
N1=20.;
N3=20.;
N4=60.;

Vr=(N2/N1)*(N4/N3);

##Output speed
n1=3600.;
n4=n1/Vr;

print'%s %.2f %s '%('\n The output speed is ',n4,' rpm.');

##Output torque
T1=200.;
T4=T1*Vr;

print'%s %.2f %s '%('\n The output torque is ',T4,' lb*in.');

##Input horsepower
hpi=T1*n1/63000.;

print'%s %.2f %s '%('\n The input horsepower is ',hpi,' hp.');

##Output horsepower
hpo=T4*n4/63000.;

print'%s %.2f %s '%('\n The output horsepower is ',hpo,' hp.');

MACHINE DESIGN
Timothy H. Wentzell, P.E.
EXAMPLE-11.1 Page No.217

The output speed is  400.00  rpm.

The output torque is  1800.00  lb*in.

The input horsepower is  11.43  hp.

The output horsepower is  11.43  hp.


## Ex2-pg219¶

In [2]:
import math

print('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.2 Page No.219\n');

Na=20.;
Nb=65.;
Nc=20.;
Nd=22.;
Ne=60.;

##train value
Vr=(Nb/Na)*(Nd/Nc)*(Ne/Nd);

print'%s %.2f %s '%('\n Train value =  ',Vr,'');

##Output speed
na=3000.;
ne=na/Vr;

print'%s %.2f %s '%('\n \Output speed = ',ne,' rpm.');

##Output torque
Ta=10.;
Te=Ta*Vr;

print'%s %.2f %s '%('\n Output torque = ',Te,' lb*in.');

##Direction

print('\n Direction\n   If Gear A is clockwise,\n   Gear B is counterclockwise.\n   Gear C is counterclockwise.\n   Gear D is clockwise. \n   Gear E is counterclockwise.');

##Output power
P=Te*ne;
P=P*math.pi/60;
print'%s %.2f %s '%('\n Output power = ',P,' W.');

MACHINE DESIGN
Timothy H. Wentzell, P.E.
EXAMPLE-11.2 Page No.219

Train value =   9.75

\Output speed =  307.69  rpm.

Output torque =  97.50  lb*in.

Direction
If Gear A is clockwise,
Gear B is counterclockwise.
Gear C is counterclockwise.
Gear D is clockwise.
Gear E is counterclockwise.

Output power =  1570.80  W.


## Ex3-pg231¶

In [3]:
import math

print('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.3 Page No.231\n');

Np=16.;
Ng=32.;
Pd=8.;

##Pitch diameter
Dp=Np/Pd;

print'%s %.2f %s '%('\n Pinion pitch diameter is ',Dp,' in.');

Dg=Ng/Pd;

print'%s %.2f %s '%('\n Gear pitch diameter is ',Dg,' in.');

##Circular pitch
Pc=math.pi*Dp/Np;

print'%s %.2f %s '%('\n Circular pitch is ',Pc,' in.');

##Centerline distance
CC=(Dp+Dg)/2.;

print'%s %.2f %s '%('\n Centerline distance is ',CC,' in.');

MACHINE DESIGN
Timothy H. Wentzell, P.E.
EXAMPLE-11.3 Page No.231

Pinion pitch diameter is  2.00  in.

Gear pitch diameter is  4.00  in.

Circular pitch is  0.39  in.

Centerline distance is  3.00  in.


## Ex4-pg236¶

In [4]:
import math

print('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.4 Page No.236\n');

##Torque in input shaft
hp=1.5;
n=3450.;
T=63000.*hp/n;

print'%s %.2f %s '%('\n Torque in input shaft is ',T,' lb*in.');

##Note-In the book T=27.4 in-lb is used instead of T=27.391304

##Output torque
Ng=24.;
Np=10.;
Tout=(Ng/Np)*T;

print'%s %.2f %s '%('\n Output torque is ',Tout,' lb*in.');

##Output speed
nout=(Np/Ng)*n;

print'%s %.2f %s '%('\n Output speed is ',nout,' rpm.');

MACHINE DESIGN
Timothy H. Wentzell, P.E.
EXAMPLE-11.4 Page No.236

Torque in input shaft is  27.39  lb*in.

Output torque is  65.74  lb*in.

Output speed is  1437.50  rpm.


## Ex5-pg241¶

In [5]:
import math

print('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.5 Page No.241\n');

##Gear train value
Na=12.;
Nb=36.;
Nc=16.;
Nd=64.;
Vr=(Nb/Na)*(Nd/Nc);

print'%s %.2f %s '%('\n Gear train value is  ',Vr,'');

##Motor torque
hp=1.5;
n=1750.;
T=63000.*hp/n;

print'%s %.2f %s '%('\n Motor torque is ',T,' in-lb.');

##Output torque
Tout=T*Vr;

print'%s %.2f %s '%('\n Output torque is ',Tout,' in-lb.');

##Output speed
nout=n/Vr;

print'%s %.2f %s '%('\n Output speed is ',nout,' rpm.');

##Directions
print('\n Directions\n  Gear A is clockwise.\n  Gear B is counterclockwise.\n  Gear C is counterclockwise.\n  Gear D is clockwise.');

##Output power
hp=T*n/63000.;

print'%s %.2f %s '%('\n Output power is ',hp,' hp.');

MACHINE DESIGN
Timothy H. Wentzell, P.E.
EXAMPLE-11.5 Page No.241

Gear train value is   12.00

Motor torque is  54.00  in-lb.

Output torque is  648.00  in-lb.

Output speed is  145.83  rpm.

Directions
Gear A is clockwise.
Gear B is counterclockwise.
Gear C is counterclockwise.
Gear D is clockwise.

Output power is  1.50  hp.


## Ex6-pg243¶

In [6]:
import math

print('MACHINE DESIGN \n Timothy H. Wentzell, P.E. \n EXAMPLE-11.6 Page No.243\n');

##Velocity ratio
N2=2400.;
N1=20.;
Vr=N2/N1;

print'%s %.2f %s '%('\n Velocity ratio =  ',Vr,'');

print('\n Possible Solution: \n Three sets of gears \n   -20 tooth and 80 tooth\n   -20 tooth and 100 tooth\n   -20 tooth and 120 tooth.');

MACHINE DESIGN
Timothy H. Wentzell, P.E.
EXAMPLE-11.6 Page No.243

Velocity ratio =   120.00

Possible Solution:
Three sets of gears
-20 tooth and 80 tooth
-20 tooth and 100 tooth
-20 tooth and 120 tooth.