Fig. 21 Comparison of Test Bearing's Configuration
3.3 EXPERIMENTAL EVALUATION OF MAIN BEARING OIL FILM PRESSURE
Fig. 20 shows experimental load condition which is based on actual condition. Actual and experimental loads show almost the same pattern in vertical direction and in horizontal direction, similar pattern with different fluctuating widths, which is considered to be the result of vertical load influence in order to give transverse load by only one cylimder in comparison with vertical load given by 6 cylinders.
Giving this loading condition to test bearings, A and B, oil film pressure is measured. Test bearing B is an improved bearing with optimized bearing width, oil groove and bearing clearance. Bearing configuration comparison is shown in Fig.21. Please refer Table 2 for the particulars of bearing and test condition.
Oil film pressure distribution's actual measurement result and calculated values are compared in Fig 22. This measurement is performed in bearing test machine described above. This comparison is expanded with bottom of lower metal as the center of expansion, which shows similar relative positions as in actual machine. Oil film pressure is generated on cam side, which showed the maximum pressure of 113MPa in preimprovement bearing. In the improved bearing with optimized bearing width, oil groove and bearing clearance, the maximum pressure was reduced by approx. 46% to 61MPa, to prove the effect of improvement. Each measured pressure is close to calculated value by EHD analysis to verify the measuring and analyzing methods of high oil film pressure in bearing under fluctuating load. At the same time, loading method of fluctuating load by simulating unit and measuring technology for high oil film pressure are established. Rupture repeatability test of fluctuating load bearing was performed by bearing test machine usimg this experiment tech-nology. Fluctuating load was loaded continuously for about eight hours and then stopped for 16 hours . This was repeated.
