Study of elastic deformation on dimensional accuracy in ironing process of spur gear

Abstract

The cold ironing process of a warm forged spur gear was applied to investigate the elastic distortions arising by the behavior of die elastic expansion and gear elastic recovery in this article. An elasto-plastic finite element simulation was performed to analyze the elastic behavior characteristics of gear and die. The effects of interference between gear and die on the elastic distortions were investigated through finite element simulation and experiment, respectively. The change of geometrical profile and dimension of the gear tooth were measured; the estimated dimension of ironed gear by finite element simulation was fitted to the experimental results well within the range of 5% relative error. Furthermore, in order to improve the dimensional accuracy of final forged gear, this study proposed a die cavity compensation method to compensate cavity of the ironing die, which was obtained by shrink fitting a outer ring into the initial ironing die. The optimum radial interference between stress ring and initial shrink-fitted die was calculated based on the Lame formula and thick wall cylinder theory. Finally, an experiment according to the proposed die cavity compensation method was carried out to examine the validity of analytical results and demonstrated that predicted dimensions could be achieved and dimensional accuracy greatly improved. It was shown that the manufacture gear satisfies the IOS6 class by measuring the iron-forged gear.

Numerical and Experimental Investigations on Residual Stress and Hardness within a Cold Forward Extruded Preform

“…However, it is well known that the numerical approaches depend upon the plastic material models, which are limited in their ability to predict and evaluate the residual stress within the cold forged product, due to the fact that the elastic deformation behavior is excluded in view of the constitutive equation, which is often called a flow stress model [ 13 , 14 , 15 , 16 , 17 , 18 , 19 ]. Consequently, a series of predictions and evaluations of the residual stress level have been attempted by adopting elasto-plastic material models [ 20 , 21 , 22 ]. A preform is widely used in a one-shot cold forging process to manufacture a three-dimensionally complicated target shape, and this is considered to cause high-leveled residual stress and critical forging defects [ 23 , 24 ].…”

The effects of theoretical models of materials and die on finite element predictions in a forging process of aluminum scroll

“…20 and Gao et al. 21 conducted a simulated and experimental study, to enable FE predictions of spur gear-forming processes to align with the high accuracy achieved through experimentation. Akash and Joun 22 solved a simple upsetting process with various combinations of materials and dies/tools, while considering deformation of the press.…”