B. A. Shotter, “Micropitting: Its
Characteristics and Implications on the Test
Requirements of Gear Oils”. Proceedings of the
Institute of Petroleum, Volume I (Performance
Testing of Lubricants), London, 1981, pp. 91-103. H. Winter and P. Oster, “Inf
适用范围
Encouraging results from a prototype micropitting test using specially designed gears (20:30 tooth ratio, tip
relief, and a 560 mm radius pinion crown) on the standard FZG test rig were reported at the 1998 AGMA Fall
Technical Meeting. Subsequently, the authors’ company purchased several sets of these experimental
AGMA test gears and attempted to develop a new test procedure to evaluate micropitting as an alternative to
FVA Procedure 54. The new relatively short test procedure involves running the test gears on the standard
FZGtest rigwith oil circulation for 168 hours at load stage 10 and 1500 rpm. The 5--gallon reservoir of test oil is
kept at 60 C throughout the test. The oil is cleaned by an in--line filter (200 =6 m) before it is injected into the
gear mesh at 2 liters/minute. At the end of test, the gears are rated for micropitting, weight loss, pitting, and
scuffing. The most common damage mode was micropitting, with only occasional occurrences of pitting and
no occurrences of scuffing. Other modes of failure such as gear tooth bending did not occur at these
conditions. The involute profile deviation of the gear teeth was not measured.
Five commercially available ISO VG 320 gear oils, with performance in the FVA Procedure 54micropitting test
ranging from FLS 9--low to FLS >10--High, were evaluated using this procedure. The degree of micropitting
coverage ranged from 34% to 7% in the new test procedure. Micropitting generally originated in the middle of
the gear tooth, instead of the root or tip. Overall, there was excellent correlation of the degree of micropitting
damage between the new test procedure and FVA Procedure 54.