{ "metadata": { "name": "", "signature": "sha256:916802be9265ec8f5947b935ca6ebb81f4ee0ab392012dea0a384748212946ca" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Ch:25 Gears" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 25-1 - Page 669" ] }, { "cell_type": "code", "collapsed": false, "input": [ "from __future__ import division\n", "from math import sqrt, pi\n", "Zp=25#\n", "Zg=60#\n", "m=5#\n", "dp=m*Zp#\n", "dg=m*Zg#\n", "CD=(dp+dg)/2#\n", "ha=m#\n", "hf=1.25*m#\n", "c=hf-ha#\n", "r=0.4*m#\n", "print \"dp is %0.0f mm \"%(dp)#\n", "print \"\\ndg is %0.0f mm \"%(dg)#\n", "print \"\\nCD is %0.1f mm \"%(CD)#\n", "print \"\\nha is %0.0f mm \"%(ha)#\n", "print \"\\nhf is %0.2f mm \"%(hf)#\n", "print \"\\nc is %0.2f mm \"%(c)#\n", "print \"\\nr is %0.0f mm \"%(r)#" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "dp is 125 mm \n", "\n", "dg is 300 mm \n", "\n", "CD is 212.5 mm \n", "\n", "ha is 5 mm \n", "\n", "hf is 6.25 mm \n", "\n", "c is 1.25 mm \n", "\n", "r is 2 mm \n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 25-2 - Page 669" ] }, { "cell_type": "code", "collapsed": false, "input": [ "N=800#\n", "P=6000#\n", "n=200#\n", "Cs=1.4#\n", "sigb=150#\n", "FOS=2#\n", "Zp=18#\n", "Zg=Zp*N/n#\n", "Y=pi*(0.154-(0.912/Zp))#\n", "p=[1 ,0 ,-9.5846, -38.135]#\n", "from sympy import symbols, solve\n", "P = symbols('P')\n", "expr = P**3*p[0]+P**2*p[1]+P*p[2]+p[3]\n", "m=solve(expr, P)[0]#\n", "dp=m*Zp#\n", "dg=m*Zg#\n", "# printing data in scilab o/p window\n", "print \"dp is %0.0f mm \"%(dp)#\n", "print \"\\ndg is %0.0f mm \"%(dg)#\n", "# Answer is given wrong in the textbook" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "dp is 77 mm \n", "\n", "dg is 309 mm \n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 25-3 - Page 670" ] }, { "cell_type": "code", "collapsed": false, "input": [ "Zp=30#\n", "N=1000#\n", "Zg=75#\n", "m=5#\n", "b=60#\n", "sigut=450#\n", "BHN=350#\n", "Cs=1.5#\n", "FOS=2#\n", "dp=m*Zp#\n", "dg=m*Zg#\n", "v=2*pi*N*dp/(60*1000*2)#\n", "Cv=3/(3+v)#\n", "sigb=450/3#\n", "Y=0.358#\n", "Sb=m*b*sigb*Y#\n", "Q=(2*Zg)/(Zp+Zg)#\n", "K=0.16*(BHN/100)**2#\n", "Sw=b*dp*Q*K#\n", "Pt=Sb*Cv/(Cs*FOS)#\n", "P=Pt*v#\n", "P=P*10**-3#\n", "print \"Sb is %0.0f N \"%(Sb)#\n", "print \"\\nSw is %0.0f N \"%(Sw)#\n", "print \"\\nP is %0.3f kW \"%(P)#\n", "\n", "#The difference in the value of Sw is due to rounding-off of the value of Q." ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Sb is 16110 N \n", "\n", "Sw is 25200 N \n", "\n", "P is 11.657 kW \n" ] } ], "prompt_number": 3 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 25-4 - Page 670" ] }, { "cell_type": "code", "collapsed": false, "input": [ "n=240#\n", "P=8000#\n", "N=1200#\n", "CD=300#\n", "Cs=1.5#\n", "alpha=20*pi/180#\n", "G=N/n#\n", "dp=CD*2/6#\n", "dg=5*dp#\n", "v=2*pi*N*dp/(60*1000*2)#\n", "Cv=3/(3+v)#\n", "Pt=P/v#\n", "Peff=Pt*Cs/Cv#\n", "m=4#\n", "b=10*m#\n", "FOS=2#\n", "Sb=Peff*FOS#\n", "sigut=600#\n", "sigb=sigut/3#\n", "Zp=dp/m#\n", "Zg=dg/m#\n", "Q=(2*Zg)/(Zp+Zg)#\n", "K=Sb/(b*dp*Q)#\n", "BHN=sqrt(K/0.16)*100#\n", "BHN=333#\n", "print \"BHN is %0.0f \"%(BHN)#" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "BHN is 333 \n" ] } ], "prompt_number": 4 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 25-5 - Page 671" ] }, { "cell_type": "code", "collapsed": false, "input": [ "alpha=20*pi/180#\n", "N=800#\n", "P=6000#\n", "sigut=450#\n", "i=5#\n", "Cs=1.3#\n", "v=3.6#\n", "FOS=2#\n", "Pt=P/v#\n", "Cv=3/(3+v)#\n", "sigb=sigut/3#\n", "dp=3.6*1000*2*60/(2*pi*N)#\n", "dp=86#\n", "Sb=Pt*Cs/Cv*FOS#\n", "#Let x be m**2*Y\n", "x=Sb/(10*sigb)#\n", "m=5#\n", "Zp=18#\n", "dp=m*Zp#\n", "Zg=i*Zp#\n", "dg=m*Zg#\n", "b=10*m#\n", "phip=m+(0.25*sqrt(dp))#\n", "ep=32+(2.5*phip)#\n", "phig=m+(0.25*sqrt(dg))#\n", "eg=32+(2.5*phig)#\n", "e=ep+eg#\n", "e=e*10**-3#\n", "Ps=Cs*Pt#\n", "r1=dp/2#\n", "r2=dg/2#\n", "Pd=e*N*Zp*b*r1*r2/(2530*sqrt(r1**2+r2**2))#\n", "Q=(2*Zg)/(Zp+Zg)#\n", "K=Sb/(b*dp*Q)#\n", "BHN=sqrt(K/0.16)*100#\n", "print \"Ps is %0.2f N \"%(Ps)#\n", "print \"\\nPd is %0.1f N \"%(Pd)#\n", "print \"\\nBHN is %0.0f \"%(BHN)#" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "Ps is 2166.67 N \n", "\n", "Pd is 1358.6 N \n", "\n", "BHN is 282 \n" ] } ], "prompt_number": 5 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "exa 25-4 - Page 672" ] }, { "cell_type": "code", "collapsed": false, "input": [ "P=9000#\n", "N=900#\n", "n=150#\n", "sigut=750#\n", "BHN=300#\n", "Cs=1.5#\n", "FOS=2#\n", "i=N/n#\n", "x=sqrt(i)#\n", "Zp=18#\n", "Zg=x*Zp#\n", "Zg=44#\n", "#Let actual speed reduction be xa\n", "xa=Zg/Zp#\n", "n1=N/xa**2#\n", "T1=P*60/(2*pi*N)#\n", "i2=N/xa#\n", "T2=N/i2*T1#\n", "m=6#\n", "dp=Zp*m#\n", "dg=m*Zg#\n", "phip=m+(0.25*sqrt(dp))#\n", "ep=16+(1.25*phip)#\n", "phig=m+(0.25*sqrt(dg))#\n", "eg=16+(1.25*phig)#\n", "e=ep+eg#\n", "e=e*10**-3#\n", "Pt=26000#\n", "Ps=Cs*Pt#\n", "r1=dp/2#\n", "r2=dg/2#\n", "b=10*m#\n", "Pd=e*i2*Zp*b*r1*r2/(2530*sqrt(r1**2+r2**2))#\n", "Q=(2*Zg)/(Zp+Zg)#\n", "sigb=sigut/3#\n", "Y=0.308#\n", "\n", "Sb=b*m*sigb*Y#\n", "K=0.16*(BHN/100)**2#\n", "Sw=b*dp*K*Q#\n", "print \"m is %0.0f mm \"%(m)#\n", "print \"\\nPd is %0.3f N \"%(Pd)#\n", "print \"\\nSw is %0.0f N \"%(Sw)#\n", " \n", " #The difference in the values is due to rounding-off of the values." ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "m is 6 mm \n", "\n", "Pd is 434.590 N \n", "\n", "Sw is 13244 N \n" ] } ], "prompt_number": 6 } ], "metadata": {} } ] }