Development of forging process for synchronized ring through numerical simulation

Synchronized ring gear is the transmission mechanism in gearbox helping in shifting gears up from the second gear to the third gear. The transmission shift feeling is one of the important elements influencing the evaluation of vehicle controllability and operational comfort. During gear shifting maximum load will be on gear teeth. There is a chance of breakage if the gear teeth design and its microstructure is not good. Hence, manufacturing of these components will play a major role in maintaining the dimension and structural integrity of the component. It has been found from literature that many of automotive synchronized ring gear components are produced from forging process for specific advantages. In the present paper, an attempt has been made to develop hot forging process for synchronized ring through numerical simulation. Process modelling and simulation based on numerical method was used to iterate and to arrive at billet size, die design and process parameter selection.

3D model of forged component was developed using CATIA-V5 and gear teeth feature in the component was generated using Autodesk Inventor. Punch and die geometry was developed based on generated 3D model. Finite element based process modelling tool DEFORM was adopted for carrying out process simulation. FE model was generated using this tool. Forging force calculation was done from first principles and forging design guideline. This was done in order to arrive at press capacity required to form the part. Forging press capacity was finalized based on the force calculation and available press in the industry. The press selected for present study was 5 tonnes. Simulation was carried for 1/3rd of the component and finally achieved force was multiplied by 3. Effective stress and strain plots were obtained and ensured that the values are not crossing the fracture limits. Forging simulation was carried out at various temperatures within the range of hot working and appropriate working temperature was suggested. Microstructure evolution was also modelled to quantify the grain refinement, grain orientation