Identification of design related distortion of gear base bodies by experimental investigations

Abstract

The economic and ecological need for reduced weight of automobiles leads to increasing activities in recent years. One way to achieve this aim is to use modified designs for components with a high weight. Here the gear box and especially the gears have a potential for significant weight reduction. But besides the functional behavior of the components under consideration the manufacturing processes must be able to produce them with high accuracy and without increasing costs. Focussing on manufacturing lines of gears, it is known on the one hand that distortion after final heat treatment can depend on gear geometry, one of the most important carriers of distortion potential. On the other hand no design rules for lightweight gears exist. Therefore in this paper first results of a research project are presented. The manufacturing line was kept constant to continuously cast steel, rolling the square blooms to semi‐finished material, forming of forging blanks with constant dimensions, annealing, turning of different shaped gear base bodies, and case hardening by low pressure carburizing in combination with high pressure gas quenching. The resulting size and shape changes as function of geometry modifications with a maximum weight reduction of 20 % will be shown and discussed.