The Fundamentals of Surface Engineering by Superfinishing using a Chemically Assisted Vibratory System

摘要

Metal gears are manufactured to their rough dimensions by some combination of metallurgical and machining steps. However, the grinding processes used to finish gears leave microscopic surface features that influence gear life. Therefore, additional processes are needed to eliminate these features while preserving the required geometric accuracy. Recent experimental results indicate that improved part surface finish, via superfinishing, can reduce contact fatigue in gears by a factor of 3, as well as enhance the bending fatigue life of their teeth by at least 10 percent. An improved surface finish also helps to maintain a fully elastohydrodynamic lubricant film that will prevent metal-to-metal contact in mating parts and will virtually eliminate contact wear and pitting fatigue. Such improvements reduce the downtime and cost for repair and maintenance. Additional benefits of superfinishing include an increase in load bearing capacity, a decrease in noise, and a decrease in coefficient of friction between mating surfaces that can reduce the amount of frictional losses inherent in any power transfer system which will lead to reduced operation and sustainment costs. Furthermore, this improved gear performance provides an opportunity to reduce component weight in new designs. This paper will review the process techniques, tests, results and benefits of applying this superfinishing process.