| 摘要 |
A drive shaft has a driving end and a driven end and is provided at the driving end with an external helical thread and a cylindrical pilot surface disposed between the thread and the driving end, the pilot surface having a diameter approximately equal to the inner diameter of the thread. During a mounting of an impeller to the drive shaft, a crest flat of an internal helical thread in the impeller rides on the pilot surface. The shaft has an additional pilot surface on the other side of the shaft thread. Upon a mounting of the impeller to the shaft, the two pilot surfaces on the shaft engage two precision impeller hub bores which straddle the threads to provide a controlled close fit of impeller and shaft to one another and to maintain the geometric axes of impeller and shaft true with one another. |
