【简答题】螺旋角【图片】=15°,齿数Z=20的标准渐开线斜齿圆柱齿轮的当量齿数Zv为________。
【简答题】已知一对渐开线标准斜齿圆柱齿轮的α n =20°,m n =4mm,z 1 =23,z 2 =98,中心距a=250mm。试计算螺旋角β、当量齿数z v1 、z v2 以及两轮的分度圆直径d、齿顶圆直径d a 、齿根圆直径d f 。
【简答题】螺旋角β=15°、齿数Z=20的标准渐开线斜齿圆柱齿轮的当量齿数Zv为________。
【判断题】Dialogue 3 ( ) 1. It is likely to be a nice day.
【单选题】七、 Talking about Weather 1 、 —It seems to be clearing up.—That will be a nice change, ?
【单选题】—It seems to be clearing up. —That will be a nice change,______?
【单选题】Nuclear ______ be really dangerous at times even though it is a nice energy in general. [ ]