Co-ordinated alignment of line shaft,propulsion gear,and turbines 1 2

Abstract

Serious tooth misalignment can occur in the second reduction mesh of a typical ship’s main propulsion gear due to a crossed-axes condition between mating pinions and gear in operation when the gear has more static loading on one of its bearings than on the other. A maximum difference between static fore and aft gear bearing loadings is recommended and illustrated by presenting a few actual line-shaft arrangements. Variation of static bearing loadings with bearing position is shown by use of influence numbers. Alignment data and considerations that must be available to produce a good co-ordinated gear to lineshaft arrangement is reviewed. The alignment of steam turbines to main propulsion gears to compensate for thermal expansions and journal-reaction position is also described.