主减速器中的圆锥滚子轴承为什么应有一定的装配预紧度?
参考答案:
为了减小在锥齿轮传动过程中产生的轴向力所引起的齿轮轴的轴向位移,以提高轴的支承刚度保证锥齿轮副的正常啮合。
They _____ on the program for almost one week before I joined them, and now we _____ it as no good results have come out.
A.had been working; are still working
B.had worked; were still working
C.have been working; have worked
D.have worked; are still working
根据课文默写(10分)
① ,儿女共沾巾。(王勃《送杜少府之任蜀川》)
② ,浅草才能没马蹄。(白居易《钱塘湖春行》)
③ ,一览众山小。(杜甫《望岳》)
④烽火连三月, 。(杜甫《春望》)
⑤ ,夜泊秦淮近酒家。(杜牧《泊秦淮》)
⑥黑云压城城欲摧, 。(李贺《雁门太守行》)
⑦不畏浮云遮望眼, 。(王安石《登飞来峰》)
⑧落红不是无情物, 。(龚自珍《己亥杂诗》)
⑨ ,灵旗空际看。(夏完淳《别云间》)
⑩五岭逶迤腾细浪, 。(毛 * * 《七律 长征》)