Yoshikatsu Shibata

Optimum tooth profile design for hypoid gear

Abstract The profile modification of tooth surface is one of the best methods of decreasing the transmission error of hypoid gears, and is not subject to the effect of productive dispersion. In the past, it was very difficult to optimize the profile modification of the tooth surface while observing and developing the tooth bearing. Accordingly a technique to analyze the relation between the tooth profile and the transmission error was developed. This technique makes it obvious that the transmission error has minimum value when the actual contact ratio becomes half of integers such as 1.5 or 2.5. A method of optimizing the tooth profile based on this important relation was also developed.

Design Method for Optimizing Contact Ratio of Hypoid Gears

Innumerable solutions can be obtained when the pitch surface of a hypoid gear is solved from the requirements of two cones. The pitch angle is determined by the Gleason method based on the idea that the tooth lengthwise curvature corresponds to the cutter radius. This study proposes a new design method that can optimize the contact ratio using the pitch angle, using the new tooth geometry advocated by Honda. The balance of the contact ratios of the convex and concave sides of a gear can be optimized by designing the pitch angle. By optimizing the contact ratio, noise and vibration performance can be improved. In addition, highly efficient gear design can be achieved by decreasing the spiral angle.The effectiveness of this optimized design method is confirmed by measuring transmission errors under load. Design examples of a highly efficient gear by reducing the spiral angle and a gear which ensures high noise and vibration performance are shown. Using this proposed method expands the design freedom of hypoid gears.© 2013 ASME

Optimum Design of Hypoid Gear Dimension and Tooth Surface

This paper describes and discusses the result of a comprehensive simulation analysis we have carried out to clarify the effects of gear dimensions, tooth surface modification, and manufacturing error on the static transmission error of automotive hypoid gears. Three representative factors have been analyzed contact ratio, crowning and pitch error because these characteristics play the most important role in tooth dimensions, tooth surface modification and manufacturing error. The analysis has clarified the effect of each factor on gear noise, making it possible to prepare a guideline for optimal design of gear dimensions and tooth surface modification under various conditions.