作业一第十章齿轮传动一.在图示二级斜齿圆柱齿轮减速器中,已知:高速级齿轮Z1=21、Z2=52、mn1=3mm、β1=1207’43”,低速级齿轮Z3=27、Z4=54、mn3=5mm,输入功率P1=10KW,n1=1450r/min,忽略效率损失,试求:(1)低速级小齿轮3的旋向,以使中间轴上的轴承所受轴向力较小;(2)低速级斜齿轮分度圆螺旋角β3为多少时,中间轴上的轴承所受轴向力完全抵消;(3)两对齿轮各啮合点处作用力的大小和方向(用三个分力表示)。习题解答:作业一作业一解:(1)齿轮3为左旋。(2)Fa1Fa2Fa32222atandT2F3333atandT2F3a2aFF32nn32TT333222tandTtandT又:3322dtandtan333n3222n2coszmtancoszmtan33n322n2zmsinzmsin"34'2810476.10)523"43'712sin275(sin)zmsinzm(sin000122n233n13作业一作业一(3)Fa1Fa2Fa32t06111tFN2.2044"43'712cos2131450101055.92dT2F2a11t1aFN3.439tanFF2r11t1rFN0.761tancosFF4t0121333tFN8.2375"34'2810cos275zzT2dT2F4a33t3aFN3.439tanFF4r33t3rFN4.879tancosFFFa4Fr1Fr2Fr3Fr4作业二二.设计一由电动机驱动的闭式斜齿圆柱齿轮传动,已知P1=17kW,n1=730r/min,i=4.5,齿轮精度为8级,齿轮对轴承不对称布置,但轴刚性较大,载荷平稳,单向传动,两班制,寿命为20年(300天/年)。作业二作业二解:一.选材料,定热处理小齿轮:40Cr,调质,260HBS大齿轮:45,调质,230HBS二.按齿面接触疲劳强度计算1.试算2HHEd131ZZu1uKT2dmm36.78式中:HHVAKKKKK0.1KA25.2作业二?精度,vfKV作业二?精度,b,FfKtH?精度,b,fKdH15.14.10.13.1试算法:初估25.24.14.115.1KKKHHVmmN222397730171055.9T610.1d21取29Z15.130335.4ZiZ12取131Z2初定o1668.1cosZ1Z12.388.121作业二5.4iu作业二MPa8.189ZE42.2ZH2H2H1HH23.1,2minHlim1H1HN1HSK91110205.41630020n60N93.0K1HN812103.95.4/NN01.1K2HN1SHMPa565684,565minMPa574161793.0Hlim2H2HN2HSKMPa556155001.1MPa617lim1HMPa550lim2...