Japan and Germany have done a lot of research in the basic research field of automobile gears. Steel roller test is a widely used method for gear basic experimental research in foreign universities and research institutions, and a large number of experimental data and research results have been obtained. The influence of gear processing defects and contact fatigue life of Japanese steel is studied.
| Types of roller | A | B | C | |
| Surface roughness | Ra / μm | 0.269 | 0.247 | 0.249 |
| Surface roughness | Rz / μm | 1.986 | 1.820 | 1.774 |
As shown in the table, the surface roughness of steel rollers of several different steels (A: JIS s48c, forging material; B: JIS s48c, rolling material; C: JIS S50C, rolling material). Figure 1 shows the shape and size diagram of steel roll test piece. Figure 2 shows the relationship between the maximum Hertz contact stress and the number of fatigue cycles of steel roll specimens of automobile gear materials with different surface roughness. The research shows that the C ‘steel roll with the lowest surface roughness has a higher contact fatigue life limit, and the C’ steel roll with surface defects simulating the machining of small holes with a diameter of 0.1 mm has the lowest contact fatigue life.
