AGMA 06FTM08-2006 pdf free.An Evaluation of FZG Micropitting Test Procedures and Results for the Crowned AGMA Test Gears.
The gears tested in this study are part of the second set of gears manufactured by AGMA and have serial numbers, 150 to 159. Since this study was a learning experienc& using the heavily modified AGMA test spur gears, the testing program was essentially a work in progress, with initial results causing methodologies to change as we pogressed. Listed below is a summary of the tests that were performed with their results:
1. Staged loading at the FVA loading stages:
Loads were at the low end of the range used by O’ConnOr [1J, Hoeprich [31, and Buzydon and Cardis [4] so they were felt to be a reasonable starting point. Results showed micropitting wear and topography change even at the lowest loads, while at higher loads, macropitting occurred. Also, a peculiar T-shaped’ contact pattern was observed.
2. Based on the above results, more detailed stress predictions were made, a more detailed study of the FZG loading procedure was performed, and the procedure for measuring tooth wear at each loading stage was refined.
3. Further tests were performed with staged loading, but at load levels that compensate for the increased contact stresses of the crowned gears. Micropitting still occurred, causing further concern about the predicted contact stresses.
4. Using revised loading stages, a higher viscosity, EP lubricant (ISO viscosity grade 220) was used as a replacement for the MIL L 23699 lubricant that was used in the previous tests. Micropitting wear was much less, but still occurred at the higher loading stages.
Tooth Topographies
The tooth geometry of the test gears is shown in Table 1 and the print specifications for leads and profiles are shown in Figs. 1 and 2. The lead specification of the test gear is straight with a tolerance of 0.005 mm.
It should be noted that the major break” of the tip relief is about halfway between the highest point of single tooth contact and the tip of each tooth. Figs. 3 and 4 show lead and profile measurements on four teeth of each gear. Comparing the charts, the profiles and leads are made very close to the specification, however, the lead crown appears to be slightly greater than the specification. As will be shown later. the measured value of lead crown depends upon where on the tooth height the measurement is taken. During initial testing of the gears, a rather peculiar, T shaped contact pattern that is shown in Fig. 5 appeared, thus imp’ying that the tooth topography was not as simple as expected from the original inspection charts. Therefore, more extensive measurements of the tooth topographies were performed.AGMA 06FTM08 pdf free download.