单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,由于轴承安装情况与受载情况的复杂性，计算轴承的径向力与轴向力时不要死记公式，而是要学会根据具体情况进行具体分析，步骤为：,*根据,F,r,求出,F,r1,和,F,r2,。,*,按表137估计,F,d1,和,F,d2,的值，它们的方向视轴承安装方向而定。注意把派生轴向力的方向与外加轴向载荷,F,ae,的方向一致的轴承标记为2，另一端的轴承标记为1。,*由于轴承最终必须处于平衡状态，所以,F,d1,和,F,d2,的值最后有一个要变化到,F,d,，,以便与,F,ae,一起达到轴向力的平衡。当,F,ae,F,d2,F,d1,则,F,d1,应增大到,F,d1,，,使,F,d1,F,ae,F,d2,，,而,F,d2,则不变。当,F,ae,F,d2,F,d1,时，为,F,d1,F,d1，,F,a2,F,d2,；,当,F,ae,F,d2,e,名 称 代 号,f,0,F,a,/C,0r,F,a,/C,0,X Y X Y,判断系数,e,调心球轴承 10000,1 (,Y,1,)0.65 (Y,2,)(e),调心滚子轴承 20000,1 (,Y,1,)0.67 (Y,2,)(e),推力调心滚子轴承,29000,1 1.2 1 1.2,圆锥滚子轴承 30000,1 0 0.4 (,Y)(e),深沟球轴承 60000,角接触球轴承,0.172 2.30 0.19,0.345 1.99 0.22,0.689 1.71 0.26,1.030 1.55 0.28,1.380,1 0 0.56 1.45 0.30,2.070 1.31 0.34,3.450 1.15 0.38,5.170 1.04 0.42,6.890 1.00 0.44,0.015 1.47 0.38,0.029 1.40 0.40,0.058 1.30 0.43,0.087 1.23 0.46,0.120 1 0 0.44 1.19 0.47,0.170 1.12 0.50,0.290 1.02 0.55,0.440 1.00 0.56,0.580 1.00 0.56,1 0 0.41 0.87 0.68,1 0 0.35 0.57 1.14,70000AC,=2,5,70000B,=,40,70000C,=1,5,表13-5 径向动载荷系数,X,与轴向动载系数,Y,因为,F,a,未知，初选,e=,0.4,0.40,F,d1,=eF,r1,F,d2,=eF,r2,于是,F,a1,=,F,ae,+F,d2,F,a2,=F,d2,=,605.05 N,F,a1,/C,0,=1005.05/20000=,0.0503,F,a2,/C,0,=605.05/20000=,0.0303,重新查表选取判断系数,e,内部轴向力:,=0.4,875.65=350.26 N,=0.4,1512.62=605.05 N,=400+,605.05=1005.05 N,轴承类型 相对轴向载荷,F,a,/,F,r,e,F,a,/,F,r,e,名 称 代 号,f,0,F,a,/C,0r,F,a,/C,0,X Y X Y,判断系数,e,调心球轴承 10000,1 (,Y,1,)0.65 (Y,2,)(e),调心滚子轴承 20000,1 (,Y,1,)0.67 (Y,2,)(e),推力调心滚子轴承,29000,1 1.2 1 1.2,圆锥滚子轴承 30000,1 0 0.4 (,Y)(e),深沟球轴承 60000,角接触球轴承,0.172 2.30 0.19,0.345 1.99 0.22,0.689 1.71 0.26,1.030 1.55 0.28,1.380,1 0 0.56 1.45 0.30,2.070 1.31 0.34,3.450 1.15 0.38,5.170 1.04 0.42,6.890 1.00 0.44,0.015 1.47 0.38,0.029 1.40 0.40,0.058 1.30 0.43,0.087 1.23 0.46,0.120 1 0 0.44 1.19 0.47,0.170 1.12 0.50,0.290 1.02 0.55,0.440 1.00 0.56,0.580 1.00 0.56,1 0 0.41 0.87 0.68,1 0 0.35 0.57 1.14,70000AC,=2,5,70000B,=,40,70000C,=1,5,表13-5 径向动载荷系数,X,与轴向动载系数,Y,0.029,没有相同的值0.0503,0.40,0.058 0.43,F,a,/C,0,表中没有与计算结果相同的,F,a1,/C,0,值，采用线性插值法求,e,0.058 0.43,(0.029 0.4),线性插值的原理,角的正切值为对边比邻边,0.0503,e,1,重新查表选取判断系数,e,重新计算轴向力,F,d1,=e,1,F,r1,=0.422,875.65=369.52 N,F,d2,=e,2,F,r2,=0.401,1512.62=606.56 N,e,1,=0.422 e,2,=0.401,F,a1,=,F,ae,+F,d2,F,a2,=F,d2,=,606.56 N,F,a1,/C,0,=1006.56/20000=,0.05033,F,a2,/C,0,=606.56/20000=,0.03033,两次计算,F,a2,/C,0,结果相差不大，故取,重新计算轴向力,e,1,=0.422,e,2,=0.401,F,a1,=,1006.56 N,F,a2,=,606.56 N,=400+,606.56=1006.56 N,3.,求轴承的当量载荷,P,1,和,P,2,查下页表并插值可求得径向载荷系数,X,和轴向载荷系数,Y,轴承类型 相对轴向载荷,F,a,/,F,r,e,F,a,/,F,r,e,名 称 代 号,f,0,F,a,/C,0r,F,a,/C,0,X Y X Y,判断系数,e,调心球轴承 10000,1 (,Y,1,)0.65 (Y,2,)(e),调心滚子轴承 20000,1 (,Y,1,)0.67 (Y,2,)(e),推力调心滚子轴承,29000,1 1.2 1 1.2,圆锥滚子轴承 30000,1 0 0.4 (,Y)(e),深沟球轴承 60000,角接触球轴承,0.172 2.30 0.19,0.345 1.99 0.22,0.689 1.71 0.26,1.030 1.55 0.28,1.380,1 0 0.56 1.45 0.30,2.070 1.31 0.34,3.450 1.15 0.38,5.170 1.04 0.42,6.890 1.00 0.44,0.015 1.47 0.38,0.029 1.40 0.40,0.058 1.30 0.43,0.087 1.23 0.46,0.120 1 0 0.44 1.19 0.47,0.170 1.12 0.50,0.290 1.02 0.55,0.440 1.00 0.56,0.580 1.00 0.56,1 0 0.41 0.87 0.68,1 0 0.35 0.57 1.14,70000AC,=2,5,70000B,=,40,70000C,=1,5,表13-5 径向动载荷系数,X,与轴向动载系数,Y,采用线性插值法求,Y,1,对轴承1,X,1,=0.44 Y,1,=1.327,1.30 0.43,(1.40 0.4),1.40 0.40,1.30 0.43,表中没有,e=0.422,Y,1,0.422,轴承2,X,2,=1 Y,2,=0,轴承工作时有中等冲击载荷，查表取,表13-6 载荷系数,载荷性质 载荷系数,f,P,无冲击或轻微冲击,1.01.2,中等冲击,1.21.8,强烈冲击,1.83.0,应用举例,电机、汽轮机、通风机、水泵等,机床、车辆、动力机械、起重机、造纸机、选矿基、冶金机械、卷扬机等,碎石机、轧钢机、钻探机、振动筛等,1.21.8,轴承的当量载荷:,P,1,=,f,p,(X,1,F,r1,+Y,1,F,a1,),P,2,=,f,p,(X,2,F,r2,+Y,2,F,a2,),=1.5,(0.44,875.65+1.327,1006.56)=2581.49 N,=1.5,(1,1512.62+0,606.56)=2268.93 N,f,p,=1.5,4.,验算轴承寿命,P,1,P,2,所以按轴承1的寿命计算,所选轴承满足寿命要求。,13-4,一农用水泵，决定选用深沟球轴承，轴颈直径,d=35mm，,转速,n=2900 r/min。,已知径向载荷,F,r,=1810N，,轴向载荷,F,a,=740N，,预期计算寿命,L,h,=6000，,试选择轴承型号。,解：1 求比值,F,a,/,F,r,=,740/1810=0.41,查表13-5，,X=0.56，Y=1.65,相对轴向载荷,f,0,F,a,/C,0r,=14.7740/15200=0.716，,对应,e,值在0.26和0.28之间,2,初选轴承型号：6207，,C=25500 N，C,0,=15200 N,P=X F,r,+Y F,a,=2234.6 N,L=8545 h,验算,Y1.55+(1.71-1.55)*,(1.03-0.716)/(1.03-0.689)=1.6973,L=4714 h,P=X F,r,+Y F,a,=2269.6 N,选轴承型号：,6307,，,C=33200 N,C,0,=19200 N,相对轴向载荷,f,0,F,a,/C,0r,=14.7740/19200=0.56656，,对应,e,值在0.22和0.26之间.,查表13-5，,X=0.56,P=X F,r,+Y F,a,=2352.72N,L=9345.67 h,Y=1.71+(1.99-1.71)*(0.689-0.56656)/(0.689-0.345)=1.81,13-5,根据工作条件，决定在轴的两端选用,=25,0,的两个角接触球轴承，如图,示。轴颈直径,d=35mm，,工作中有中等冲击，转速,n=1800r/min，,已知两轴,承的径向载荷分别为,F,r1,=3390N，F,r2,=1040N，,外加轴向载荷,F,ae,=870N，,作用,方向指向轴承1，试确定其工作寿命。,解：对于70000,AC,型轴承,F,d,=0.68F,r,1,F,ae,F,r2,F,r1,F,d2,F,d1,2,正装,F,d1,=0.68F,r1,=0.683390=2305.2N,F,d2,=0.68F,r1,=0.681040=707.2N,按,F,a1,=,F,ae,+F,d2,=1577.2 N F,d1,，,F,a1,=,F,d1,=2305.2N,F,a2,=F,d1,F,ae,=1435.2N,F,a1,/F,r1,=0.68,e=0.68,查表13-5，,X=1，Y=0,F,a2,/F,r2,=1.38,查表13-5，,X=0.41，Y=0.87,P,1,=,XF,r,=3390 N,P,2,=,XF,r,+,YF,a,=0.411040+0.871435.2=1675N,查表（国家标准）：7207,AC,轴承的,C=30500N,L,h,=1998 h,复习思考题：,1、滚动轴承由哪些基本元件组成？它们的作用是什么？,2、滚动轴承有哪些类型？试比较3、6、7、,N,这四种类型轴承,的主要特点和适用场合？,3、轴承代号的前置、基本和后置代号各代表什么意义？,4、为什么内圈固定、外圈转动时，作用在固定套圈上的载荷的,变化频率比内圈转动、外圈固定时要高一些？,5、什么是滚动轴承的接触角？什么是载荷角？它们之间有没有,联系？,6、为什么轴向力的大小会影响某些类型轴承的承载滚动体数目？,7、滚动轴承类型的选择应考虑哪些因素？高速轻载的工作条件,宜选用哪一类轴承？高速重载又宜选用哪一类轴承？,8、什么叫游动支撑？在什么情况下采用?,9、,什么叫滚动轴承的基本额定寿命？什