MEDIUM-SPEED DIESEL PROPULSION REDUCTION GEARING

Current interest in medium speed diesel propulsion for maritime vessels is driving a third generation of reduction gear designs. The first generation nourished in the 1930s and looked remarkably like those proposed today. However, by comparison, they were designed with low power density; used lightly loaded gear teeth and bearings; had to cope with poorly filtered and blended lubricants; used relatively inaccurate manufacturing techniques, and were based on inaccurate analysis of operating conditions. The second generation, starting in the late 1960s and continuing through 1980, had the benefit of the rational AGMA gear design method, Raimondi and Boyd's work on bearing design, and sophisticated techniques for alignment and vibratory analysis. Power and loading levels increased and many variations of equipment were tried: reversing engines, reversing gears, and reversing propellers. Individually, each was successful and we now have the benefit of two decades of operating experience for this design generation. This paper will explore the design principles of the gear/engine/propeller/auxiliary equipment package to define the guiding parameters for the third generation based upon the lessons provided by the experience gained in the two previous generations.