机械精度设计与检测课件：极限与配合国家标准的认知

极限与配合国家标准的认知《机械精度设计与检测》

目录标准公差系列01基本偏差系列02公差与配合的标注03常用尺寸孔、轴的公差带与配合04内容极限与配合的国家标准1.标准公差系列（1）标准公差因子（公差单位）标准公差因子是用以确定标准公差的基本单位，该因子是基本尺寸的函数，是制定标准公差数值的基础。（2）公差等级确定尺寸精确程度的等级称为公差等级。国家标准设置了20个公差等级。（3）尺寸分段为了减少标准公差的数目、统一公差值、简化公差表格以便于实际应用，国家标准对基本尺寸进行了分段，对同一尺寸段内的所有基本尺寸，在相同公差等级情况下，规定相同的标准公差。内容极限与配合的国家标准1.标准公差系列表标准公差数值（GB/T1800.1-2009）公差等级IT01IT0IT1IT2IT3IT4IT5IT6IT7IT8IT9IT10IT11IT12IT13IT14IT15IT16IT17IT18基本尺寸/mm/μm/mm~30.30.50.81.2234610142540600.100.140.250.400.601.01.4>3~60.40.611.52.545812183048750.120.180.300.480.751.21.8>6~00.40.611.52.546915223658900.150.220.360.580.901.52.2>10~180.50.81.2235811182743701100.180.270.430.701.101.82.7>18~300.611.52.546912213352841300.210.330.520.841.302.13.3>30~500.611.52.54711162539621001600.250.390.621.001.602.53.9>50～800.81.2235813193046741201900.300.460.741.201.903.04.6>80~12011.52.5461015223554871402200.350.540.871.402.203.55.4>120~1801.223.55812182540631001602500.400.631.001.602.504.06.3>180~250234.571014202946721151852900.460.721.151.852.904.67.2>250~3152.54681216233252811302103200.520.811.302.103.205.28.1>315~40035791318253657891402303600.570.891.402.303.605.78.9>400~500468101520274063971552504000.630.971.552.504.006.39.7>6~1013内容极限与配合的国家标准2.基本偏差系列基本偏差是用以确定公差带相对零线位置的那个极限偏差，可以是上偏差或下偏差，一般是指靠近零线的那个偏差。表

基本偏差表基本偏差代号及其特点轴a～zc，28种基本偏差孔A～ZC，28种基本偏差轴的基本偏差es=ei+Ts或ei=es−Ts孔的基本偏差一般情况EI=−es或ES=−ei特殊情况：基本尺寸>3～500mm，标准公差等级≤IT8的K、M、N和标准公差等级≤IT7的P−ZC，孔和轴的基本偏差的符号相反，绝对值相差一个Δ值，即ES=−ei+Δ，Δ=ITn−IT（n−1）或在孔比轴低一级时Δ=Th−Ts内容极限与配合的国家标准2.基本偏差系列图基本偏差系列内容极限与配合的国家标准表轴的基本偏差值（GB/T1800.1-2009）（总表）基本尺寸/mm基本偏差上偏差es下偏差ei所有公差等级5,6784~7≤3>7大于至abccddeefffgghjsjk−3−270−140−60−34−20−14−10−6−4−20偏差等于−2−4−60036−270−140−70−46−30−20−14−10−6−40−2−4−+10610−280−150−80−56−40−25−18−13−8−50−2−5−+101014−290−150−95−−50−32−−16−−60−3−6−+1014181824−300−160−110−−65−40−−20−−70−4−8−+2024303040−310−170−120−−80−50−−25−−90−5−10−+204050−320−180−1305065−340−190−140−−100−60−−30−−100−7−12−+206580−360−200−15080100−380−220−170−−120−72−−36−−120−9−15−+30100120−410−240−180120140−460−260−200−−145−85−−43−−140−11−18−

+3

0140160−520−280−210160180−580−310−230180200−660−340−240−−170−100−−50−−150−13−21−+40200225−740−380−260225250−820−420−280250280−920−480−300−−190−110−−56−−170−16−26−+40280315−1050−540−330315355−1200−600−360−−210−125−−62−−180−18−28−+40355400−1350−680−400400450−1500−760−440−−230−135−−68−−200−20−32−+50450500−1650−840−480基本尺寸/mm基本偏差下偏差ei所有公差等级大于至mnprstuvxyzzazbzc−3+2+4+6+10+14−+18−+20−+26+32+40+6036+4+8+12+15+19−+23−+28−+35+42+50+80610+6+10+15+19+23−+28−+34−+42+52+67+971014+7+12+18+23+28−+33−+40−+50+64+90+1301418+39+45−+60+77+108+1501824+8+15+22+28+35−+41+47+54+63+73+98+136+1882430+41+48+55+64+75+88+118+160+2183040+9+17+26+34+43+48+60+68+80+94+112+148+200+274405054+70+81+97+114+136+180+242+3255065+11+20+32+41+53+66+87+102+122+144+172+226+300+4056580+43+59+75+102+120+146+174+210+274+360+48080100+13+23+37+51+71+91+124+146+178+214+258+335+445+585100120+54+79+104+144+172+210+254+310+400+525+690120140+15+27+43+63+92+122+170+202+248+300+365+470+620+800140160+65+100+134+190+228+280+340+415+535+700+900160180+68+108+146+210+252+310+380+465+600+780+1000180200+17+31+50+77+122+166+236+284+350+425+520+670+880+1150200225+80+130+180+258+310+385+470+575+740+960+1250225250+84+140+196+284+340+425+520+640+820+1050+1350250280+20+34+56+94+158+218+315+385+475+580+710+920+1200+1550280315+98+170+240+350+425+525+650+790+1000+1300+1700315355+21+37+62+108+190+268+390+475+590+730+900+1150+1500+1900355400+114+208+294+435+530+660+820+1000+1300+1650+2100400450+23+40+68+126+232+330+490+595+740+920+1100+1450+1850+2400450500+132+252+360+540+660+820+1000+1250+1600+2100+2600内容表轴的基本偏差值（GB/T1800.1-2009）（分表1）基本尺寸/mm基本偏差上偏差es下偏差ei所有公差等级5,6784~7≤3>7大于至abccddeefffgghjsjk−3−270−140−60−34−20−14−10−6−4−20偏差等于−2−4−60036−270−140−70−46−30−20−14−10−6−40−2−4−+10610−280−150−80−56−40−25−18−13−8−50−2−5−+101014−290−150−95−−50−32−−16−−60−3−6−+1014181824−300−160−110−−65−40−−20−−702430−4−8−+203040−310−170−120−−80−50−−25−−90−5−10−+204050−320−180−1305065−340−190−140−−100−60−−30−−100−7−12−+206580−360−200−15080100−380−220−170−−120−72−−36−−120−9−15−+30100120−410−240−180120140−460−260−200−−145−85−−43−−140−11−18−

+3

0140160−520−280−210160180−580−310−230180200−660−340−240−−170−100−−50−−150−13−21−+40200225−740−380−260225250−820−420−280250280−920−480−300−−190−110−−56−−170−16−26−+40280315−1050−540−330315355−1200−600−360−−210−125−−62−−180−18−28−+40355400−1350−680−400400450−1500−760−440−−230−135−−68−−200−20−32−+50450500−1650−840−480内容表轴的基本偏差值（GB/T1800.1-2009）（分表2）基本尺寸/mm基本偏差下偏差ei所有公差等级大于至mnprstuvxyzzazbzc−3+2+4+6+10+14−+18−+20−+26+32+40+6036+4+8+12+15+19−+23−+28−+35+42+50+80610+6+10+15+19+23−+28−+34−+42+52+67+971014+7+12+18+23+28−+33−+40−+50+64+90+1301418+39+45−+60+77+108+1501824+8+15+22+28+35−+41+47+54+63+73+98+136+1882430+41+48+55+64+75+88+118+160+2183040+9+17+26+34+43+48+60+68+80+94+112+148+200+274405054+70+81+97+114+136+180+242+3255065+11+20+32+41+53+66+87+102+122+144+172+226+300+4056580+43+59+75+102+120+146+174+210+274+360+48080100+13+23+37+51+71+91+124+146+178+214+258+335+445+585100120+54+79+104+144+172+210+254+310+400+525+690120140+15+27+43+63+92+122+170+202+248+300+365+470+620+800140160+65+100+134+190+228+280+340+415+535+700+900160180+68+108+146+210+252+310+380+465+600+780+1000180200+17+31+50+77+122+166+236+284+350+425+520+670+880+1150200225+80+130+180+258+310+385+470+575+740+960+1250225250+84+140+196+284+340+425+520+640+820+1050+1350250280+20+34+56+94+158+218+315+385+475+580+710+920+1200+1550280315+98+170+240+350+425+525+650+790+1000+1300+1700315355+21+37+62+108+190+268+390+475+590+730+900+1150+1500+1900355400+114+208+294+435+530+660+820+1000+1300+1650+2100400450+23+40+68+126+232+330+490+595+740+920+1100+1450+1850+2400450500+132+252+360+540+660+820+1000+1250+1600+2100+2600内容极限与配合的国家标准轴的基本偏差数值表格里内容极限与配合的国家标准表孔的基本偏差值（GB/T1800.1-2009）（总表）基本尺寸/mm基本偏差下偏差EI上偏差ES所有公差等级678≤8>8≤8>8≤8>8大于至ABCCDDEEFFFGGJKMN−3+270+140+60+34+20+14+10+6+4+2+2+4+600−2−2−4−436+270+140+70+46+30+20+14+10+6+4+5+6+10−1+Δ−−4+Δ−4−8+Δ0610+280+150+80+56+40+25+18+13+8+5+5+8+12−1+Δ−−6+Δ−6−10+Δ01014+290+150+95−+50+32−+16−+6+6+10+15−1+Δ−−7+Δ−7−12+Δ014181824+300+160+110−+65+40−+20−+7+8+12+20−2+Δ−−8+Δ−8−15+Δ024303040+310+170+120−+80+50−+25−+9+10+14+24−2+Δ−−9+Δ−9−17+Δ04050+320+180+1305065+340+190+140−+100+60−+30−+10+13+18+28−2+Δ−−11+Δ−11−20+Δ06580+360+200+15080100+380+220+170−+120+72−+36−+12+16+22+34−3+Δ−−13+Δ−13−23+Δ0100120+410+240+180120140+460+260+200−+145+85−+43−+14+18+26+41−3+Δ−−15+Δ−15−27+Δ0140160+520+280+210160180+580+310+230180200+660+340+240−+170+100−+50−+15

+22+30+47−4+Δ−−17+Δ−17−31+Δ0200225+740+380+260225250+820+420+280250280+920+480+300−+190+110−+56−+17+25+36+55−4+Δ−−20+Δ−20−34+Δ0280315+1050+540+330315355+1200+600+360−+210+125−+62−+18+29+39+60−4+Δ−−21+Δ−21−37+Δ0355400+1350+680+400400450+1500+760+440−+230+135−+68−+20+33+43+66−5+Δ−−23+Δ−23−40+Δ0450500+1650+840+480基本尺寸/mm基本偏差Δ值上偏差ES公差等级≤IT7>IT7标准公差等级大于至P~ZCPRSTUVXYZZAZBZC345678−3

在大于7级的相应数值上增加一个Δ−6−10−14−−18−−20−−26−32−40−6000000036−12−15−19−−23−−28−−35−42−50−8011.51346610−15−19−23−−28−−34−−42−52−67−9711.523671014−18−23−28−−33−−40−−50−64−90−1301233791418−39−45−−60−77−108−1501824−22−28−35−−41−47−54−63−73−98−136−1881.52348122430−41−48−55−64−75−88−118−160−2183040−26−34−43−48−60−68−80−94−112−148−200−2741.53459144050−54−70−81−97−114−136−180−242−3255065−32−41−53−66−87−102−122−144−172−226−300−405235611166580−43−59−75−102−120−146−174−210−274−360−48080100−37−51−71−91−124−146−178−214−258−335−445−58524571319100120−64−79−104−144−172−210−254−310−400−525−690120140−43−63−92−122−170−202−248−300−365−470−620−80034671523140160−65−100−134−190−228−280−340−415−535−700−900160180−68−108−146−210−252−310−380−465−600−780−1000180200−50−77−122−166−236−284−350−425−520−670−880−115034691726200225−80−130−180−258−310−385−470−575−740−960−1250225250−84−140−196−284−340−425−520−640−820−1050−1350250280−56−94−158−218−315−385−475−580−710−920−1200−155044792029280315−98−170−240−350−425−525−650−790−1000−1300−1700315355−62−108−190−268−390−475−590−730−900−1150−1500−1900457112132355400−114−208−294−435−530−660−820−1000−1300−1650−2100400450−68−126−232−330−490−595−740−920−1100−1450−1850−2400557132334450500−132−252−360−540−660−820−1000−1250−1600−2100−2600内容表孔的基本偏差值（GB/T1800.1-2009）（分表1）基本尺寸/mm基本偏差下偏差EI上偏差ES所有公差等级678≤8>8≤8>8≤8>8大于至ABCCDDEEFFFGGJKMN−3+270+140+60+34+20+14+10+6+4+2+2+4+600−2−2−4−436+270+140+70+46+30+20+14+10+6+4+5+6+10−1+Δ−−4+Δ−4−8+Δ0610+280+150+80+56+40+25+18+13+8+5+5+8+12−1+Δ−−6+Δ−6−10+Δ01014+290+150+95−+50+32−+16−+6+6+10+15−1+Δ−−7+Δ−7−12+Δ014181824+300+160+110−+65+40−+20−+7+8+12+20−2+Δ−−8+Δ−8−15+Δ024303040+310+170+120−+80+50−+25−+9+10+14+24−2+Δ−−9+Δ−9−17+Δ04050+320+180+1305065+340+190+140−+100+60−+30−+10+13+18+28−2+Δ−−11+Δ−11−20+Δ06580+360+200+15080100+380+220+170−+120+72−+36−+12+16+22+34−3+Δ−−13+Δ−13−23+Δ0100120+410+240+180120140+460+260+200−+145+85−+43−+14+18+26+41−3+Δ−−15+Δ−15−27+Δ0140160+520+280+210160180+580+310+230180200+660+340+240−+170+100−+50−+15

+22+30+47−4+Δ−−17+Δ−17−31+Δ0200225+740+380+260225250+820+420+280250280+920+480+300−+190+110−+56−+17+25+36+55−4+Δ−−20+Δ−20−34+Δ0280315+1050+540+330315355+1200+600+360−+210+125−+62−+18+29+39+60−4+Δ−−21+Δ−21−37+Δ0355400+1350+680+400400450+1500+760+440−+230+135−+68−+20+33+43+66−5+Δ−−23+Δ−23−40+Δ0450500+1650+840+480内容表孔的基本偏差值（GB/T1800.1-2009）（分表2）基本尺寸/mm基本偏差Δ值上偏差ES公差等级≤IT7>IT7标准公差等级大于至P~ZCPRSTUVXYZZAZBZC345678−3

在大于7级的相应数值上增加一个Δ−6−10−14−−18−−20−−26−32−40−6000000036−12−15−19−−23−−28−−35−42−50−8011.51346610−15−19−23−−28−−34−−42−52−67−9711.523671014−18−23−28−−33−−40−−50−64−90−1301233791418−39−45−−60−77−108−1501824−22−28−35−−41−47−54−63−73−98−136−1881.52348122430−41−48−55−64−75−88−118−160−2183040−26−34−43−48−60−68−80−94−112−148−200−2741.53459144050−54−70−81−97−114−136−180−242−3255065−32−41−53−66−87−102−122−144−172−226−300−405235611166580−43−59−75−102−120−146−174−210−274−360−48080100−37−51−71−91−124−146−178−214−258−335−445−58524571319100120−64−79−104−144−172−210−254−310−400−525−690120140−43−63−92−122−170−202−248−300−365−470−620−80034671523140160−65−100−134−190−228−280−340−415−535−700−900160180−68−108−146−210−252−310−380−465−600−780−1000180200−50−77−122−166−236−284−350−425−520−670−880−115034691726200225−80−130−180−258−310−385−470−575−740−960−1250225250−84−140−196−284−340−425−520−640−820−1050−1350250280−56−94−158−218−315−385−475−580−710−920−1200−155044792029280315−98−170−240−350−425−525−650−790−1000−1300−1700315355−62−108−190−268−390−475−590−730−900−1150−1500−1900457112132355400−114−208−294−435−530−660−820−1000−1300−1650−2100400450−68−126−232−330−490−595−740−920−1100−1450−1850−2400557132334450500−132−252−360−540−660−820−1000−1250−1600−2100−2600内容极限与配合的国家标准孔的基本偏差数值表格里内容极限与配合的国家标准3.公差与配合的标注（1）公差带代号与配合代号孔、轴的公差带代号由基本偏差代号和公差等级数字组成，例如H7、F7、K7、h7、g6、m6、等。配合代号写成分数形式，分子为孔的公差带代号，分母为轴的公差带代号。如H7/g6或H7.g6。（2）图样中尺寸公差的标注形式零件图中尺寸公差的两种标注形式。在装配图上，主要标注配合代号，即标注孔、轴的基本偏差代号及公差等级。图

孔、轴公差在零件图上的标注图

装配图公差配合标注内容

±191.孔45S6，查孔基本偏差表2IT6在大于7级的S偏差数值加上△，查表大于7级的S偏差ES=-43微米，所以45S6偏差ES=-43+△，查出来6级△=5，所以45S6ES=-38微米，查标准公差表尺寸45，IT6T=16微米，所以EI=-54微米3.查孔基本偏差表格1,280M6ES=-20+△，查△=9微米

，但是根据表格说明规定M6ES=-9微米，查公差表格T=32微米，EI=-41微米孔Φ45S6Φ45—公称尺寸、基本尺寸S—大写孔基本偏差代号6—精度等级IT6S6—公差带内容极限与配合的国家标准2.基本偏差系列例：查表确定Φ25H8/p8,Φ25P8/h8孔与轴的极限偏差，并计算这两个配合的极限盈隙。（1）查表1-2确定孔和轴的标准公差IT8=33μm（2）Φ25H8/p8基孔H8：EI=0μm轴p8：ei=+22μm孔H8：ES=EI+Th=0+33=+33μm轴p8：es=ei+Ts=+22+33=+55μm（3）Φ25P8/h8基轴h8：es=0μmei=es-Ts=0-33=-33μmP8:ES=-22μmEI=ES-Th=-22-33=-55μmXminXmin内容孔和轴的基本偏差计算例1：查表计算孔f25P8的基本偏差和另外一个偏差查孔的基本偏差数值表，f25在24-30mm区间，对应P的基本偏差为-22μm，是上偏差，因此有ES=-22μm。内容孔和轴的基本偏差计算例1：查表计算孔f25P8的基本偏差和另外一个偏差查标准公差数值表，f25在18-30mm区间，IT8=33μm，因此下偏差ES=EI-IT8=-55μm公差等级IT01IT0IT1IT2IT3IT4IT5IT6IT7IT8IT9IT10IT11IT12IT13IT14IT15IT16IT17IT18基本尺寸/mm/μm/mm~30.30.50.81.2234610142540600.100.140.250.400.601.01.4>3~60.40.611.52.545812183048750.120.180.300.480.751.21.8>6~00.40.611.52.546915223658900.150.220.360.580.901.52.2>10~180.50.81.2235811182743701100.180.270.430.701.101.82.7>18~300.611.52.546912213352841300.210.330.520.841.302.13.3>30~500.611.52.54711162539621001600.250.390.621.001.602.53.9>50～800.81.2235813193046741201900.300.460.741.201.903.04.6>80~12011.52.5461015223554871402200.350.540.871.402.203.55.4>120~1801.223.55812182540631001602500.400.631.001.602.504.06.3>180~250234.571014202946721151852900.460.721.151.852.904.67.2>250~3152.54681216233252811302103200.520.811.302.103.205.28.1>315~40035791318253657891402303600.570.891.402.303.605.78.9>400~500468101520274063971552504000.630.971.552.504.006.39.7内容例2：查表计算轴f25f6的基本偏差和另外一个偏差查轴的基本偏差数值表，f25在24-30mm区间，对应f的基本偏差为-20μm，是上偏差，因此有es=-20μm。孔和轴的基本偏差计算内容例2：查表计算轴f25f6的基本偏差和另外一个偏差查标准公差数值表，f25在18-30mm区间，IT6=12μm，因此下偏差ei=es-IT6=-32μm孔和轴的基本偏差计算公差等级IT01IT0IT1IT2IT3IT4IT5IT6IT7IT8IT9IT10IT11IT12IT13IT14IT15IT16IT17IT18基本尺寸/mm/μm/mm~30.30.50.81.2234610142540600.100.140.250.400.601.01.4>3~60.40.611.52.545812183048750.120.180.300.480.751.21.8>6~00.40.611.52.546915223658900.150.220.360.580.901.52.2>10~180.50.81.2235811182743701100.180.270.430.701.101.82.7>18~300.611.52.546912213352841300.210.330.520.841.302.13.3>30~500.611.52.54711162539621001600.250.390.621.001.602.53.9>50～800.81.2235813193046741201900.300.460.741.201.903.04.6>80~12011.52.5461015223554871402200.350.540.871.402.203.55.4>120~1801.223.55812182540631001602500.400.631.001.602.504.06.3>180~250234.571014202946721151852900.460.721.151.852.904.67.2>250~3152.54681216233252811302103200.520.811.302.103.205.28.1>315~40035791318253657891402303600.570.891.402.303.605.78.9>400~500468101520274063971552504000.630.971.552.504.006.39.7内容孔和轴的基本偏差计算例2：查表计算轴f60s7的基本偏差和另外一个偏差查轴的基本偏差数值表，f60在50-65mm区间，对应s的基本偏差为+53μm，是下偏差，因此有ei=+53μm。基本尺寸/mm基本偏差下偏差ei所有公差等级大于至mnprstuvxyzzazbzc−3+2+4+6+10+14−+18−+20−+26+32+40+6036+4+8+12+15+19−+23−+28−+35+42+50+80610+6+10+15+19+23−+28−+34−+42+52+67+971014+7+12+18+23+28−+33−+40−+50+64+90+1301418+39+45−+60+77+108+1501824+8+15+22+28+35−+41+47+54+63+73+98+136+1882430+41+48+55+64+75+88+118+160+2183040+9+17+26+34+43+48+60+68+80+94+112+148+200+274405054+70+81+97+114+136+180+242+3255065+11+20+32+41+53+66+87+102+122+144+172+226+300+4056580+43+59+75+102+120+146+174+210+274+360+48080100+13+23+37+51+71+91+124+146+178+214+258+335+445+585100120+54+79+104+144+172+210+254+310+400+525+690120140+15+27+43+63+92+122+170+202+248+300+365+470+620+800140160+65+100+134+190+228+280+340+415+535+700+900160180+68+108+146+210+252+310+380+465+600+780+1000180200+17+31+50+77+122+166+236+284+350+425+520+670+880+1150200225+80+130+180+258+310+385+470+575+740+960+1250225250+84+140+196+284+340+425+520+640+820+1050+1350250280+20+34+56+94+158+218+315+385+475+580+710+920+1200+1550280315+98+170+240+350+425+525+650+790+1000+1300+1700315355+21+37+62+108+190+268+390+475+590+730+900+1150+1500+1900355400+114+208+294+435+530+660+820+1000+1300+1650+2100400450+23+40+68+126+232+330+490+595+740+920+1100+1450+1850+2400450500+132+252+360+540+660+820+1000+1250+1600+2100+2600内容孔和轴的基本偏差计算例3：查表计算轴f60s7的基本偏差和另外一个偏差查标准公差数值表，f60在50-80mm区间，IT7=30μm，因此上偏差es=ei+IT7=83μm公差等级IT01IT0IT1IT2IT3IT4IT5IT6IT7IT8IT9IT10IT11IT12IT13IT14IT15IT16IT17IT18基本尺寸/mm/μm/mm~30.30.50.81.2234610142540600.100.140.250.400.601.01.4>3~60.40.611.52.545812183048750.120.180.300.480.751.21.8>6~00.40.611.52.546915223658900.150.220.360.580.901.52.2>10~180.50.81.2235811182743701100.180.270.430.701.101.82.7>18~300.611.52.546912213352841300.210.330.520.841.302.13.3>30~500.611.52.54711162539621001600.250.390.621.001.602.53.9>50～800.81.2235813193046741201900.300.460.741.201.903.04.6>80~12011.52.5461015223554871402200.350.540.871.402.203.55.4>120~1801.223.55812182540631001602500.400.631.001.602.504.06.3>180~250234.571014202946721151852900.460.721.151.852.904.67.2>250~3152.54681216233252811302103200.520.811.302.103.205.28.1>315~40035791318253657891402303600.570.891.402.303.605.78.9>400~500468101520274063971552504000.630.971.552.504.006.39.7内容例4：查表计算孔f25F7的基本偏差和另外一个偏差查孔的基本偏差数值表，f25在24-30mm区间，对应F的基本偏差为+20μm，是下偏差，因此有EI=+20μm。孔和轴的基本偏差计算内容例4：查表计算孔f25F7的基本偏差和另外一个偏差查标准公差数值表，f25在18-30mm区间，IT7=21μm，因此上偏差ES=EI+IT6=+41μm孔和轴的基本偏差计算公差等级IT01IT0IT1IT2IT3IT4IT5IT6IT7IT8IT9IT10IT11IT12IT13IT14IT15IT16IT17IT18基本尺寸/mm/μm/mm~30.30.50.81.2234610142540600.100.140.250.400.601.01.4>3~60.40.611.52.545812183048750.120.180.300.480.751.21.8>6~00.40.611.52.546915223658900.150.220.360.580.901.52.2>10~180.50.81.2235811182743701100.180.270.430.701.101.82.7>18~300.611.52.546912213352841300.210.330.520.841.302.13.3>30~500.611.52.54711162539621001600.250.390.621.001.602.53.9>50～800