How to design Spur Gear

clear

clc

H=100;

np=1120;

phin=20;

Np=18;

Ng=72;

R=0.95;

N=1000000000;

Ko=1;

nd=2;

Qv=6;

Kb=1;

Pd=4;

mb=1.2;

% diametral pitch selection

disp('DIAMETRAL PITCH SELECTION->')

dp=Np/Pd;

disp('The value of dp in inch =')

disp(dp);

dg=Ng/Pd;

disp('The value of dg in inch =')

disp(dg);

Yp=0.309;

Yg=0.4324;

Jp=0.32;

Jg=0.415;

v=(3.14*dp*np)/12;

disp('The value v in ft/min =')

disp(v);

Wt=(33000*H)/v;

disp('The value Wt in lbf =')

disp(Wt);

cons=(12-Qv)^(2/3);

B=0.25*cons;

A=50+56*(1-B);

Kv=((A+sqrt(v))/A)^(B);

Kr=0.658-(0.0759)*log(1-0.95);

Mk=(N)^(-0.8255);

Ynp=1.355*Mk;

jk=(R/Pd)^(-0.0178)

Yng=1.3558*jk;

cnk=(R)^(-0.023);

Znp=1.4488*cnk;

knk=(R/Pd)^(-0.023);

Zng=1.4488*knk;

F=(4*3.14)/Pd;

ksk=F*sqrt(Ynp);

kk=(ksk/Pd)^(0.0535);

Ks=11.22*kk;

Cmc=1;

Cpm=1;

Ce=1;

Cma=0.175;

f=(F)/(10*dp);

Cpf=f-0.0375+(0.0125*F);

Km=1+1*(Cpf*1+Cma*1);

Cp=2300;

mg=4;

mn=1;

csk=(dp)/(dp+1);

rcb=(cos(20)*sin(20))/2;

I=csk*rcb;

% pinion tooth bending

disp('PINION TOOTH BENDING-->')

hr=320;

Kt=1;

Sc=170000;

St=86.2*hr+12730;

Fb=(nd*Wt*Ko*Ks*Pd*Km*Kb*Kr)/(Jp*St*Yng);

disp('Facewidth necessary to resist bending fatigue =')

disp(Fb);

cs=(Cp*Kt*Kr)/(Sc*Znp);

jj=(cs)^(2);

Fw=(jj*nd*Wt*Ko*Kv*Ks*Km*Cpf)/(dp*I);

disp('Facewidth necessary to resist wear fatigue =')

disp(Fw);

% correcting the above values

disp('CORRECTING THE ABOVE VALUES-->')

F=3.5;

disp('Facewidth =')

disp(F);

fp=(F)/(10*dp);

pk=(F*sqrt(Yp))/Pd;

sk=(pk)^(0.0535);

Ks=1.192*sk;

Cpf=fp-0.0375+(0.0125*F);

Km=1+1*(Cpf*1+0.175*1);

disp('Value of km is =')

disp(Km);

sigmap=(2502*1*1.48*1.147*4*1.259*1)/(3.5*0.32);

disp('Bending stress induced by Wt in psi=')

disp(sigmap);

FOSp=(40310*0.938)/(1*0.885*19100);

disp('Factor of safety in bending of pinion is =')

disp(FOSp);

%gear tooth bending

disp('GEAR TOOTH BENDING-->')

sigmag=(19100*0.32)/0.415;

disp('value of sigmag =')

disp(sigmag);

FOSg=(40310*0.961)/(1*0.885*14730);

disp('Factor of safety of gear in bending =');

disp(FOSg);

% pinion tooth gear

disp('PINION TOOTH GEAR-->')

gk=sqrt((2502*1*1.48*1.147*1.259*1)/(4.5*3.5*0.129));

sigmacp=2300*gk;

disp('Value of sigmacp in psi =')

disp(sigmacp);

FOS=(170000*0.9)/(1*0.885*118000);

disp('Factor of safety =');

disp(FOS);

%pinion bending

disp('PINION BENDING-->')

kl=(FOS)^(2);

ch=1;

sigmacg=118000;

Sc=170000;

%gear tooth wear

disp('GEAR TOOTH WEAR-->')

FOSgw=(Sc*0.929)/(1*0.885*sigmacg);

disp('Factor of safety =');

disp(FOSgw);

% gear in wear

disp('GEAR IN WEAR-->')

ml=(FOSgw)^(2);

% Rim

disp('RIM-->')

ht=2.25/Pd;

disp('Whole depth in inch is =');

disp(ht);

tr=mb*ht;

disp('Thickness of rim in inch is =');

disp(tr);

[Sam Chak]

@Swapnil Bansal, Can you show the design methodology flowchart for Spur Gear?

Answer 1

[Himanshu]

Hey Swapnil,

I understand that you are trying to design a spur gear.

You can refer the following implementation shared on file exchange on MALTAB Central for the same. Please go through the GitHub repository mentioned on the following page for a better understating of how a spur gear can be implemented with MATLAB.

https://www.mathworks.com/matlabcentral/fileexchange/79721-spur-gear-designer

Hope this helps!