Heat Flux and Temperature Distribution in Gear Hobbing Operations

Abstract

Thermal deviations in gear hobbing are one of the main reasons for wet machining. To reduce lubricant, especially for dry machin- ing of large modulus, it is necessary to compensate these thermal deviations.Gear hobbing is a very complex technology, where chip geometries are changing continuously. To measure cutting forces during machining a simplified fly cutting test is commonly used. Within this study a modification of the fly cutting test was necessary to enable the measurement of temperature and temperature distribution in the gear during the process.For a better understanding, in addition numerical simulations are performed to calculate the heat flow and thermal distribution. Thereby, a two step simulation procedure was applied. The generated heat during chip formation was evaluated in the first step. The second step is a heat flow simulation, where the generated heat from the first step was used. In this simulation part, the heat flow and thermal deviations are calculated, and also chip removal is taken into account. Thereby, different simulation strategies are used to reduce the calculation time, which will be described within this paper.The results are showing a good agreement between the measured and calculated temperature fields in chip formation and heat flow.