STUDY OF HELICOPTER GEAR LUBRICATION.
Abstract
Studies to determine the effect of hardness on the fatigue life of gears were continued. In constant load tests preceded by break-in, using MAAG B gears and with two synthetic tetraester-base lubricants (designated MIL-L-23699(A) and MIL-L-23699(B)), it was found that an increase in hardness of about five Rockwell C (Rc) units resulted in a doubling of gear life. At the same constant transmitted load of 496 lb, the MIL-L-23699(A) lubricant was superior in regard to fatigue life, giving about 3-1/2 times the life of MIL-L-23699(B) over a hardness range of 40 to 63 Rc. The magnitude of transmitted load was found to have a considerable effect on fatigue life over a range of hardness. In tests with MIL-L-23699(A) oil, reducing the load from 637 to 496 lb resulted in from 637 to 496 lb resulted in a nine-fold increase in life. Based on a straight-line relationship between load and log life, this amounts to doubling the gear life for each decrease in transmitted load of 45 lb. Tests run on gear systems of different chemical composition showed a considerable variation in score load and fatigue life. There is apparently no simple relationship between chemical composition, surface finish, or hardness, and the performance of these gears. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 17, 1966
- Accession Number
- AD0634033
Entities
People
- D. E. Stuart
- D. R. Bailey
- J. E. Lumos
- S. J. Beaubien