鈑金抽牙孔徑計算鈑金件的抽牙加工,包括沖孔,翻孔,攻牙的過程,在孔徑計算時,先確定翻孔內徑d1,然后依材料的圓孔翻邊系數kt,求得沖孔直徑d0,螺紋加工分為有屑加工及無屑加工.有屑加工是以切削的方式,將材料去除,形成螺紋.因要去除材料,故坯料要保留較多,底徑d取較小值.無屑加工是以擠壓的方式,使材料塑性變形,形成螺紋.因無需去除材料,坯孔內的材料只作塑性流動,故坯料保留較少,底徑d取較大. 鈑金件的螺紋加工大多采用無屑加工,底徑計算以無屑加工方式確定.依設計所要求加工的螺紋型號,查表1,2,3,4,得該螺紋的標稱直徑D.螺距P.則翻孔內徑d1=D-P/2 (1) 表1,2,3,4分列了10mm以下公制粗牙,細牙及UNC UNF螺紋的規格尺寸.若為有屑加工,則d1=D-P (2) 表1.公制粗牙螺紋(1/8)圖一: H=0.866025 P d2=d-0.649519 p H1=0.541266 P d1=d-1.082532 p D=d D2=d2 D1=d1 D1=d1螺紋之標稱(1)螺距P內螺紋根徑D有效徑D2內徑D1123外螺紋外徑d有效徑d2根徑d1M1M1.2M1.10.250.250.251.0001.1001.2000.8380.9381.0380.7290.8290.929M1.6M1.4M1.80.30.350.351.4001.6001.8001.2051.3731.5731.0751.2211.421M2M2.5M2.20.40.450.452.0002.2002.5001.7401.9082.2081.5671.7132.013M3*0.5M4*0.7M3.50.50.60.73.0003.5004.0002.6753.1103.5452.4592.8503.242M5*0.8M6M4.50.750.814.5005.0006.0004.0134.4805.3503.6884.1344.917M8M7M911.251.257.0008.0009.0006.3507.1888.1865.9176.6477.647M101.510.0009.0268.376表2 公制細牙螺紋之基本尺寸圖二.JIS公制螺紋(4/8) H=0.866025 P d2=d-0.649519 p H1=0.541266 P d1=d-1.082532 p D=d D2=d2 D1=d1 螺紋之標稱螺距p內螺紋根徑D有效徑D2內徑D1外螺紋外徑d有效徑d2根徑d1M1*0.2M1.1*0.2M1.2*0.2M1.4*0.2M1.6*0.2M1.8*0.20.20.20.20.20.20.21.0001.1001.2001.4001.6001.8000.8700.9701.0701.2701.4701.6700.7830.8830.9831.1831.3831.583M2*0.25M2.2*0.250.250.252.0002.2001.8382.0381.7291.929M2.5*0.35M3*0.35M3.5*0.350.350.350.352.5003.0003.5002.2732.2733.2732.1212.6213.121M4*0.5M4.5*0.5M5*0.5M5.5*0.50.50.50.50.54.0004.5005.0005.5003.6754.1754.6755.1753.4593.9594.4594.959M6*0.75M7*0.750.750.756.0007.0005.5136.5135.1886.188M8*1M*0.7510.758.0008.0007.3507.5136.9177.188M9*1M9*0.7510.759.0009.0008.3508.5137.9178.188M10*1.25M10*1M10*0.751.2510.7510.00010.00010.0009.1889.3509.5138.6478.9179.188表三 JIS美英統一制粗牙螺紋(1/2)圖三. P = 25.4/n H=(0.866025/n)*25.4 d=(d)*25.4 H1=(0.541266/n)*25.4 d2=(d-0.649519/n)*25.4 D=d D2=d2 D1=d1 d1=(d-1.082532/n)*25.4螺紋之標稱螺紋數(每25.4mm)n螺距P(參考)內螺紋根徑D有效徑D2內徑D1外螺紋外徑d有效徑d2根徑d112參考No.2-56 UNCNo.1-64 UNCNo.3-48 UNC0.0730-64UNC0.0860-56UNC0.0990-48UNC6456480.39690.45360.52921.8542.1842.5151.5981.8902.1721.4251.6941.941No.4-40 UNCNo.5-40 UNCNo.6-32 UNC0.1120-40UNC0.1250-40UNC0.1380-32UNC4040320.63000.63500.79382.8453.1753.5052.4332.7642.9902.1562.4872.647No.8-32 UNC 10-24 UNCNo.12-24 UNC0.1640-32UNC0.1900-24UNC0.2160-24UNC3224240.79381.05831.05834.1664.8265.4863.6504.1384.7983.3073.6804.3411/4-20 UNC5/16-18 UNC3/8-16 UNC0.2500-20UNC0.3125-18UNC0.3750-16UNC2018161.27001.41111.58756.3507.9389.5255.5247.0218.4944.9766.4117.805表四 .JIS美英統一制粗牙螺紋(2/2)圖四. P = 25.4/n H=(0.866025/n)*25.4 d=(d)*25.4 H1=(0.541266/n)*25.4 d2=(d-0.649519/n)*25.4 D=d D2=d2 D1=d1 d1=(d-1.082532/n)*25.4螺紋之標稱螺紋數(每25.4mm)n螺距P(參考)內螺紋根徑D有效徑D2內徑D1外螺紋外徑d有效徑d2根徑d112參考No.0-80 UNFNo.2-64 UNFNo.1-72 UNF0.0600-80 UNF0.0730-72 UNF0.0860-64 UNF8072640.31750.35280.39691.5241.8542.1841.3181.6261.9281.1811.4731.755No.4-48 UNFNo.5-44 UNFNo.3-56 UNF0.0990-56 UNF0.1120-48 UNF0.1250-44 UNF5648440.45360.52920.57732.5152.845。