Analysis of Effect of Built-Up Edge on Hobbed Gear Tooth Surface Roughness

Abstract

Large gears or through-hardened and tempered gears are often put to practical use without any finishing subsequent to hobbing. It has been found that in these types of gears tooth surface roughness plays a decisive role in improving the loading capacity. In this research experiments were performed, considering, among the factors influencing the surface roughness, the effect of the builtup edge to be the most significant. Therefore, the BUEs resulting from various hobbing conditions are measured. Further, the cutting thickness is calculated theoretically for each case, as one of the factors influencing the formations of the BUEs. The interrelationship among the cutting thickness, the size of the BUEs, and the surface roughness has been found out, thus enabling a qualitative prediction of the surface roughness from the knowledge of the cutting thickness.