(13.5)-13-7 滾動軸承例題分析

第13章滾動軸承§13-1概述§13-2滾動軸承的主要類型和代號§13-3滾動軸承的類型選擇§13-4滾動軸承的工作情況§13-5滾動軸承尺寸的選擇§13-6軸承裝置的設(shè)計§13-7滾動軸承例題分析§13-7

滾動軸承例題分析設(shè)根據(jù)工作條件決定在軸的兩端反裝兩個角接觸球軸承。已知軸上齒輪受切向力Ft=2200N，徑向力Fr=900N，軸向力Fa=400N，齒輪分度圓直徑d=314mm，齒輪轉(zhuǎn)速n=520rpm，運轉(zhuǎn)中有中等沖擊載荷，軸承預(yù)期計算壽命L’h=15000h。設(shè)初選兩個軸承型號均為7207C，試驗算軸承是否可達(dá)到預(yù)期計算壽命的要求。32020021解：1.求徑向載荷

先求兩處徑向載荷垂直和水平分量

Fr2VFr1VFr2HFr1HFteFaeFreFaeFreFteFd=eFr求總徑向載荷2.求兩軸承的派生軸向力Fd1和Fd2

查表得7207C軸承的基本額定動載荷與基本額定靜載荷為C=30500NC0=20000N對于70000C型軸承，派生軸向力Fd=1.14FrFd=0.68FrFd=eFrFd=Fr／(2Y)70000B(a=40o)70000AC(a=25o)70000C(a=15o)角接觸球軸承圓錐滾子軸承其中e為判斷系數(shù)，按下表13-5選取21FaeFreFteFd2Fd1軸承類型相對軸向載荷Fa/Fr

≤eFa/Fr>e名稱代號f

0Fa/C0r

Fa/C0

XYXY判斷系數(shù)e調(diào)心球軸承10000—

—1(Y1)0.65(Y2)(e)調(diào)心滾子軸承20000—

—1(Y1)0.67(Y2)(e)推力調(diào)心滾子軸承29000—

—11.211.2圓錐滾子軸承30000—

—100.4(Y)(e)深溝球軸承60000角接觸球軸承0.1722.300.190.3451.990.220.6891.710.261.0301.550.281.380—100.561.450.302.0701.310.343.4501.150.385.1701.040.426.8901.000.440.0151.470.380.0291.400.400.0581.300.430.0871.230.460.120100.441.190.470.1701.120.500.2901.020.550.4401.000.560.5801.000.56—

—100.410.870.68—

—100.350.571.1470000AC

α=25?70000Bα=40?

70000C

α=15?表13-5徑向動載荷系數(shù)X與軸向動載系數(shù)Y因為Fa未知，初選e=0.4

0.40Fd1=eFr1Fd2=eFr2于是Fa1=Fae+Fd2Fa2=Fd2=605.05NFa1/C0=1005.05/20000=0.0503Fa2/C0=605.05/20000=0.0303重新查表選取判斷系數(shù)e

派生軸向力:=0.4×875.65=350.26N

=0.4×1512.62=605.05N=400+605.05=1005.05N軸承類型相對軸向載荷Fa/Fr

≤eFa/Fr>e名稱代號f

0Fa/C0r

Fa/C0

XYXY判斷系數(shù)e調(diào)心球軸承10000—

—1(Y1)0.65(Y2)(e)調(diào)心滾子軸承20000—

—1(Y1)0.67(Y2)(e)推力調(diào)心滾子軸承29000—

—11.211.2圓錐滾子軸承30000—

—100.4(Y)(e)深溝球軸承60000角接觸球軸承0.1722.300.190.3451.990.220.6891.710.261.0301.550.281.380—100.561.450.302.0701.310.343.4501.150.385.1701.040.426.8901.000.440.0151.470.380.0291.400.400.0581.300.430.0871.230.460.120100.441.190.470.1701.120.500.2901.020.550.4401.000.560.5801.000.56—

—100.410.870.68—

—100.350.571.1470000AC

α=25?70000Bα=40?

70000C

α=15?表13-5徑向動載荷系數(shù)X與軸向動載系數(shù)Y0.029沒有相同的值0.05030.400..0580.43Fa/C0重新查表選取判斷系數(shù)e

重新計算派生軸向力Fd1=e1Fr1=0.422×875.65=369.52N

Fd2=e2Fr2=0.401×1512.62=606.56Ne1=0.422e2=0.401Fa1=Fae+Fd2Fa2=Fd2=606.56NFa1/C0=1006.56/20000=0.05033Fa2/C0=606.56/20000=0.03033兩次計算Fa2/C0結(jié)果相差不大，故取

重新計算軸向力e1=0.422e2=0.401Fa1=1006.56NFa2=606.56N=400+606.56=1006.56N3.求軸承的當(dāng)量動載荷P1和P2

查下頁表并插值可求得徑向載荷系數(shù)X和軸向載荷系數(shù)Y軸承類型相對軸向載荷Fa/Fr

≤eFa/Fr>e名稱代號f

0Fa/C0r

Fa/C0

XYXY判斷系數(shù)e調(diào)心球軸承10000—

—1(Y1)0.65(Y2)(e)調(diào)心滾子軸承20000—

—1(Y1)0.67(Y2)(e)推力調(diào)心滾子軸承29000—

—11.211.2圓錐滾子軸承30000—

—100.4(Y)(e)深溝球軸承60000角接觸球軸承0.1722.300.190.3451.990.220.6891.710.261.0301.550.281.380—100.561.450.302.0701.310.343.4501.150.385.1701.040.426.8901.000.440.0151.470.380.0291.400.400.0581.300.430.0871.230.460.120100.441.190.470.1701.120.500.2901.020.550.440