High Frequency Vibration-Monitoring Techniques for Incipient Fault Detection in Spiral Bevel Gear Systems
AGMA Technical Paper No. 109.38
Presented at the April 1977 AGMA Aerospace Committee Meeting, Orlando, FL
Authors: Raymond J. Drago, Senior Engineer, Advanced Power Train Technology
Robert Aronson, Engineering Specialist - Diagnostics, Product Assurance
Boeing Vertol Company
A continuing, cooperative program, involving both the Product Assurance and Advanced Power Train Technology Departments, has been underway for several years in an effort to investigate the feasibility of utilizing high frequency vibration monitoring techniques for detecting the presence and monitoring the progression of faults in rotating machinery, particularly helicopter transmissions. At this point, the feasibility of the concept has been firmly established and current efforts are aimed at expanding the range of applications and developing a better understanding of the response of specific systems to various stimulii. The effort reported herein addressed pitting and spalling (simulated and natural) and tooth root crack progression in spiral bevel gears.
Fault initiation and progression monitoring testing were conducted on the Boeing Vertol Gear Research Test Stand. The test specimens utilized were standard CH-47C engine transmission spiral bevel gears (35/43 ratio), run at torque levels ranging from 10% to 270% of maximum aircraft single engine (S.E.) rating (3750 hp) on this four-square, locked in torque rig. Verification tests were conducted utilizing the Boeing Vertol full scale engine transmission closed loop test stand, at torque levels ranging from 10% to 130% of S.E. rating.