文摘
A comprehensive thermal model is developed to analyse the heat transfer mechanism in form grinding of involute gears. The model analyses the thermal effects of a transient non-uniform heat source, moving with a three-dimensional curved shape, on the involute tooth profile. The variation of the contact geometry along the tooth profile is considered and analysed in detail, including the local grinding depth, equivalent wheel diameter and local contact arc length as well as the variation of the three-dimensional heat flux distribution and the heat partitioning to different thermal parts on the curved tooth profile. Based on the model established, the grinding temperature distribution patterns along the involute contact profile under different Peclet numbers, numbers of teeth and gear modules have been investigated. Along the tooth profile, the temperature increases significantly with the rolling angle. Grinding temperatures along the tooth profile of a straight spur gear, made of 20CrMnTi low-carbon steel, are measured using a special test rig designed with thermocouples imbedded into workpiece at different measurement positions. The results demonstrate that the calculated temperature distribution along the tooth profile has a rather good agreement with the measured result. This research provides a new method to predict grinding temperature in form grinding mode of precision gears.
