A、必有F<sub>Rsub>=F<sub>1sub>+F<sub>2sub> B、不可能有F<sub>Rsub>=F<sub>1sub>+F<sub>2sub> C、必有F<sub>Rsub>>F<sub>1sub>,F<sub>Rsub>>F<sub>2sub> D、可能有F<sub>Rsub><F<sub>1sub>,F<sub>Rsub><F<sub>2sub>
A、必有F<sub>Rsub>=F<sub>1sub>+F<sub>2sub> B、不可能有F<sub>Rsub>=F<sub>1sub>+F<sub>2sub> C、必有F<sub>Rsub>>F<sub>1sub>,F<sub>Rsub>>F<sub>2sub> D、可能有F<sub>Rsub><F<sub>1sub>,F<sub>Rsub><F<sub>2sub>
A、f<sub>rsub>ρ<sub>ssub>gL B、f<sub>ρsub>Lρg C、(f<sub>ρsub>-f<sub>rsub>)Lρg D、f<sub>rsub>(ρ<sub>ssub>-ρ)gL
A、f<sub>rsub>ρ<sub>ssub>gL B、f<sub>ρsub>Lρg C、(f<sub>ρsub>-f<sub>rsub>)Lρg D、f<sub>rsub>(ρ<sub>ssub>-ρ)
A、某轴用一对圆锥滚子轴承支承,外圈窄边相对安装,已知两轴承所承受的径向载荷分别为F<sub>rⅠsub>=9000N,F<sub>rⅡsub>=5000N,其内部轴向力分别为F<sub>SⅠsub>=2430N,F<sub>SⅡsub>=1350N,传动件作用于轴上的轴向力F<sub>Asub>=1000N,判断系数e=0.32,当F<sub>asub>/F<sub>rsub>≤e时,X=1,Y=0,当F<sub>asub>/F<sub>rsub>>e时,X=0.4,Y=1.88。试分别计算出轴承的当量动载荷。r /> rc="https://img.ppkao.com/2018-07/tangxueping/2018072009392591839.jpg" />
A、R<sub>1sub>与R<sub>3sub>串联后与R<sub>2sub>并联 B、R<sub>1sub>与R<sub>3sub>并联后与R<sub>2sub>串联 C、R<sub>1sub>与R<sub>2sub>并联后与R<sub>3sub>串联 D、R<sub>1sub>与R<sub>2sub>串联后与R<sub>3sub>并联
A、R<sub>1sub>烧坏,R<sub>2sub>不会烧坏 B、R<sub>1sub>、R<sub>2sub>均烧坏 C、R<sub>1sub>未烧坏,R<sub>2sub>烧坏 D、R<sub>1sub>、R<sub>2sub>均未烧坏
A、以下所示的结构设计简图中,已知轴的转速n=1470r/min,角接触轴承1上的径向载荷R<sub>1sub>=800N,角接触轴承2上的径向载荷R<sub>2sub>=1900N,轴向载荷F<sub>asub>=1200N,两个轴承的额定动载荷C<sub>rsub>均为C<sub>rsub>=38600N,e=0.68,S=0.7R,A/R≤e,x=1,y=0;A/R>e,x=0.41,y=0.87,f<sub>tsub>=1.1,f<sub>psub>=1.2,求受载最大的轴承的工作寿命L<sub>hsub>。r /> rc="https://img.ppkao.com/2018-09/wenxueying/2018090609482576109.jpg" />
A、在下图所示的电路中,L=0.8uH,C<sub>1sub>=C<sub>2sub>=20pF,R<sub>ssub>=10kΩ,R<sub>Lsub>=5kΩ,Q<sub>0sub>=100。试求回路在有载情况下的谐振频率f<sub>0sub>,谐振电阻R<sub>Σsub>,回路有载Q值和通频带BW<sub>0.7sub>。r /> rc="https://img.ppkao.com/2019-05/wuacheng/2019051316592798223.jpg" />
A、R<sub>1sub>〉R<sub>3sub>〉R<sub>2sub> B、R<sub>1sub>=R<sub>2sub>=R<sub>2sub> C、R<sub>1sub>〈R<sub>3sub>〈R<sub>2sub> D、都不对