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Recently,four-wheel drive vehicle (hereinafter abbreviated as 4WD vehicle) chassis dynamometer has been developed and in the course of practical use for many kinds of test. The 4WD chassis dynamometer technology, however, involves many new requirements and advanced techniques which were not required for conventional chassis dynamometers. This study has described a generation mechanism for driving force distribution through construction of a dynamic model for the resolution of unsolved issues in composite dynamic systems of 4WD vehicle and 4WD chassis dynamometer. Additionally, we have clarified the reasons why driving force distribution on-the-road is different from that on the chassis dynamometer, and clarified that the work value of driving shaft depends upon the combination of chassis dynamometer types and 4WD vehicles types. The micro-slip theory (hereinafter abbreviated as MS theory) utilized for the analysis is the basic theory that can explain that inclinations.

In order to prolong rolling bearing fatigue life under mixed or boundary lubrication conditions, we have developed a specific smooth surface with small indentations by using the concept of micro EHL (elastohydrodynamic lubrication). These indentations or pits act as a carrier of lubricant from the inlet to the inside of the contact area. Therefore, lubrication performance of this surface is better than that of a superfinished surface. We have already demonstrated the ability of forming an oil film using this proposed surface. However, reliability of fatigue life for this surface was not sufficiently investigated. Therefore, we have conducted several rolling bearing fatigue life tests with this surface as compared to a superfinished surface. Lambda values of these tests were from 0.45 to 2.10. Results of these tests indicated that the life of the bearings containing rollers with this surface texture was between 2.0 to 13 times longer than that of normal bearings.