1、i P 2000FTMll O, UltraSafe Gear Systems - Single Tooth Bending Fatigue Test Results by: R. Drago, Boeing Helicopters, A. Isaacson - ? .- -o i - -5 E 1- - - .- - - - o -,- 02m. b_.l*,_ ar., Figure 26 - About 24 Hours of Safe Operating Time May be Provided For This Root Oriented Crack Occurrence Concl
2、usions Based on the results of this test program and the analytical efforts which preceded it, we have reached the following conclusions: 1. Multiple load path gear blanks can be successfully designed 2. Crack propagation can be predicted, with reasonable accuracy, by monitoring the change in stiffn
3、ess of the cracked tooth relative to the remaining uncracked teeth on the same gear. This change should also be detectable in a dynamic environment via the resultant once per gear revolution change in stiffness which will appear as an impact load O 3. Gear tooth and blank design can significantly en
4、hance safety by providing lower stresses & multiple load paths through the use of the dual rim concept. 4. Additional system design considerations, as defined in Reference 4, can further enhance UltraSafe gear system benefits to include improvements in both noise and weight characteristics in concer
5、t with improved safety. Recommendations While these test results, combined with the previously reported analytical results, are certainly very encouraging, it is important to conduct a series of similar tests in a dynamic transmission environment. References 1. Rose, H. J., “What “HUMS” Means to Boe
6、ing Helicopters,” Aerospace Technology Seminar, Republic of Singapore - 1995 2. Rose, H. J., “Diagnostic Systems Research Applicable to Helicopter Transmissions,” American Helicopter 46h Annual Forum, Sheraton Washington Hotel, Washington, D. C., USA, May 1990 3. Astridge, D. G., “Vibration Health M
7、onitoring of Westland 30 Helicopter Transmission - Development and Service Experience,” 4 1 MFPG Meeting NAQTC Patuxent River, MD, USA, October 1986 4. Drago, R. J., et. AI., “UltraSafe Gear Systems for Critical Applications - Initial Development,” Paper No. 97FTM 10, American Gear Manufacturers Ass
8、ociation Fall Technical Meeting, November 9-1 1, San Diego, CA 5. Drago, Raymond J., Sane, Ashok & Brown, Frederick W. “Ingranaggi “Ultrasafe” per Applicazioni Critiche - la Parte: Impostazione Del Problema,” Orgarni Di Transmissione (Journal of the Italian Gear Manufacturers Association, In Italian
9、), March 1999 6. Drago, Raymond J., Sane, Ashok & Brown, Frederick W., “ Ingranaggi “Ultrasafe” per Applicazioni Critiche - 3a Parte: Ottimizzazione,” Orgami Di Transmissione Pages 76-80 (Journal of the Italian Gear Manufacturers Association, In Italian), July 1999 7. Lewicki, David G., Drago, Raymo
10、nd J., Sane, Ashok D. & Wawrzynek, Paul A., “Three Dimensional Crack Propagation Studies,” 4th World Congress on Gearing and Power Transmission, Paris, France, March 1999 ACKNOWLEDGMENT This work is being supported by the National Rotorcraft Technology Center. -9- COPYRIGHT American Gear Manufacturers Association, Inc.Licensed by Information Handling Services
