Numerical-experimental investigation on the rabbit ear formation mechanism in gear rolling

作者:Li, Jin; Wang, Guangchun*; Wu, Tao
来源:International Journal of Advanced Manufacturing Technology, 2017, 91(9-12): 3551-3559.
DOI:10.1007/s00170-017-0009-7

摘要

The formation of rabbit ears during the gear rolling process, caused by the generating motion between the gear roller and the blank, is a common and undesirable phenomenon encountered in gear rolling. It generally leads to fold defects, waste of material, and decline in mechanical properties after removal, seriously affecting the quality of the gear to be formed. In this paper, a finite element model of gear rolling is first established, the gear rolling process are simulated, and the rabbit ear formation mechanism and its morphology change are studied. The phenomenon and the morphology of the rabbit ear are then verified experimentally. The formation mechanism of the rabbit ear was analyzed by means of the stress state, the deformation distribution, and the material flow. The results show the following: (1) the continuous localized contact between the gear roller and the blank induces the material on the surface area of the tooth sequential plastic deformation, while at the same time, the material is squeezed by the tooth flank of the gear roller and flows towards the direction of the smaller resistance, that is, the flank of the tooth. The difference in the material flow velocity between the flank of the tooth and the center of the tooth leads to the formation of the rabbit ear; (2) the asymmetric shape of the ears appears to be related to the different direction of friction exerted on two sides of the tooth depending on the rotational direction of the gear roller. These findings provide a scientific basis to further explore measures to control the rabbit ear defect and improve the forming quality in gear rolling.