An Assessment of Some Forms of Follower-Tooth Reduction Gear and its Application to Helicopter Main Rotor Gearboxes.

摘要

This Report presents a critical assessment of the cylindrical rotary form of the follower-tooth reduction gear, indicating deficiencies and suggesting improvements. Consideration has been given to the mechanism's application to helicopter main gearboxes and a design study formulated. It is not considered competitive with current types because: (1) Although the specific mass of a basic follower-tooth gear is about the same as that of conventional transmissions in similar configurations, the latter have more potential for mass reduction, and their efficiency is higher. (2) The addition of tail rotor and ancillary drive take-offs would increase complexity and weight to a greater extent than in conventional systems. (3) The geometric arrangement and the type and function of the speed reducing components are such that the mechanism would be more sensitive to environmental conditions. (4) Although components are geometrically simple, high manufacturing standards, quality control and assembly difficulties would reflect adversely on costs. (5) Refurbishment would probably entail replacement of most power-transmitting components, bearings and seals, whereas conventional systems normally require only new bearings and seals. (Author)