A novel multipass incremental gear rolling process with blank and rolling die axes crossed

With continuous improvement of gear performance requirements, gear rolling process has received increasing attention and has broad application prospects. In this study, a novel multipass gear rolling process with blank and rolling die axes crossed is proposed. The finite element model was established to study the plastic deformation mechanism and material flow during the proposed process with three passes. The simulation results show that the equivalent strain distribution and material flow laws of the three passes are consistent, and the severe equivalent strain and material flow displacement are distributed in the area near the tooth flank and root. As the passes progress, the tooth height and the cumulative degree of plastic deformation gradually increase, and the last pass has a certain shaping effect on the tooth profile. Meanwhile, the experimental research was carried out, and the microstructure characteristics and hardness contour of the formed gear were obtained. The experimentally formed gear has clear and complete tooth profile, and the cent tooth uniformity is excellent. The grains in the formed tooth region are refined, and evident fibrous tissues appear in the surface of the tooth flank and root. The hardness of the formed gear is improved, and the maximum hardness is distributed in the surface of the tooth root, which is 32.5% higher than that of the original blank. The proposed process has advantages, such as high versatility of the rolling die and no complicated die phase adjustment, and provides a new idea for the rolling of large modulus gears.