互换性与测量技术基础第十章答案王伯平

第十章螺纹结合的互换性1.由螺母M24×2－6H查表得TD2=0.224mmTD1=0.375mm中径D2=22.701mm小径D1=21.835mm∴小径D1max=21.835+0.375=22.210mmD1min=21.835mm中径D2max=22.701+0.224=22.925mmD2min=22.701mm由螺栓M24×2－6h查表得Td2=0.170mmTd=0.280mm中径d2=22.701mm∴大径dmax=24mmdmin=24－0.280=23.720mm中径d2max=22.701mmd2min=22.701－0.17=22.531mm公差带图：2.d2作用=d2实+(fp+fα/2)=21.9+0.0866+0.057=22.044mm∵d2作用=22.044mmd2max=22.051mmd2单一=21.9mmd2min=21.851mm∴该螺栓合格。3.D2作用=D2实－（fp+fα/2）=18.61－（0.069+0.035）=18.506mm∵D2作用=18.506mmD2min=18.376mmD2单一=18.61mmD2max=18.656mm∴该螺母中径合格。4.1)20次测量结果列表序号Piυi=PPiυi2112.003+0.0030.000009212.005+0.0050.000025311.995-0.0050.000025411.998-0.0020.000004512.003+0.0030.000009612.003+0.0030.000009711.990-0.0100.000100811.995-0.0050.000025911.998-0.0020.0000041012.005+0.0050.0000251112.005+0.0050.0000251211.998-0.0020.0000041312.003+0.0030.0000091411.998-0.0020.0000041512.010+0.0100.0001001612.005+0.0050.0000251711.995-0.0050.0000251811.998-0.0020.0000041912.000002011.995-0.0050.000025ΣPi=240.002nPPi12.000n1ii=0.002n1i2i=0.0004562)计算单次测量的标准偏差估计值σ'，即丝杠单个螺距误差ΔPΔP=σ′120000456.01Nn1i2i=0.48×10-2=0.0048mm根据依拉达准则判断测量列中不存在粗大误差3)计算测量列算术平均值的标准偏差的估计值σ'τ，即丝杆螺距累计误差ΔPLΔPL=σ'τ=200048.0N=0.0011mm5.M24－6H中径和顶径公差带代号公称直径普通螺纹代号M36×2－5g6g－20旋合长度为20mm————顶径公差带代号—————中径公差带代号螺距（细牙）公称直径（大径）普通螺纹代号M30×2－6H/5g6g外螺纹顶径公差带代号外螺纹中径公差带代号内螺纹中径和顶径公差带代号（相同）螺距（细牙）公称直径普通螺纹代号6.d2max=14.701－0.038=14.663mmd2min=14.701－0.198=14.503mmfp=0.01732mm,fα/2=0.0219mm由d2作用=d2单+(fp+fα/2)≤d2max得d2单≤d2max－(fp+fα/2)=14.6234mm∴单一中径合格的条件d单一≥d2min=14.503且d2单≤14.623mm7.1)由d2=M－3dm+0.866Pdm=0.577P得d2=M－0.865P=21.151－0.865×2.5=18.9885mmd2max=18.391mm此螺纹塞规中径不合格。2)由d2=M－dm(1+2sin1)+2ctg2Pδlimd2=2lim222lim222lim222lim22dPdddMdPdmmM22222226.0634.17.1866.0195.0=±3.51µm±0.0035mm