Precision forging of asymmetric spur gear

The use of asymmetric gear tooth profile can be considered as a creative and innovative solution for many power transmission applications where gear wheels often rotate in only one direction. However, the production of the asymmetric gear profile by the conventional thread cutting method is dependent on the cutting tool design and the machining process. Recent studies in this area have shown that asymmetric profiles designed independently from the cutting tool are more efficient. In precision gear forging, on the other hand, the final tooth profile is determined by the die geometry, and therefore the limitations of the cutting tool can be eliminated totally. The precision forging of asymmetric spur gear was studied in this thesis and the design criteria for the asymmetric spur gear die were presented. For this purpose, upper bound energy analyses (UBEA) and finite elements (FE) simulations of the gear forging process were carried out to determine the forging load and die stresses. The gear tooth profile modifications of the die required for the dimensional accuracy of the forged gear were evaluated. The UBEA and FEA results were compared with the experimental studies. The study shows that precision forging is a feasible method for the manufacturing of asymmetric spur gears and the method eliminates the limitations of the tooth profile of gear cutting or generation methods. However, the design of the forging die is critical in the success of the process. The design criteria presented in the study can be used successfully.