Numerical Simulation And Experimental Research On Hot And Cold Composite Forging Process For Bevel Gear

Bevel gear is widely used as an important part in power and speed transmission device.Hot and cold composite forging process is one of the important process for the production ofstraight bevel gears and spiral bevel gears. The forging billet shape directly affect the full ofthe tooth form. The amount of the cold finishing namely hot forging tooth profile is one of theimportant factors affecting the tooth surface roughness. Because of technical privacyprotection, there are few articles home and abroad reported about billet shape and hot forgingtooth profile. Selecting a kind of car straight bevel gear and a kind of spiral bevel gear astypical parts, this article did some further study on the key technology of hot and coldcomposite forging process, and provided guidance for practical application.A cylindrical bar was selected to form straight bevel gear. It should be upset before hotforging in order to remove the oxide scale that produced in heating and obtain the suitablebillet size that placed in forging die. After analyzing load-stroke curves, material flow,equivalent stress distribution, equivalent strain distribution and temperature distribution, thisarticle summed up the rule of upsetting height on the full of the tooth form and pointed out thereasonable upsetting height.Hot forging tooth profile is one of the important factors affecting the tooth surfaceroughness. In order to improve the quality of tooth surface, this article made equidistant toothprofile and non-equidistant tooth profile schemes. Using Deform-3D software, material flow,stress and strain distribution of different profiles during cold finishing was got. Throughanalyzing the simulation results the rule of hot forging tooth profile on tooth surfaceroughness and the reason of folding defect produced in cold finishing was obtained, and thebest profile scheme was determined. Process tests were carried out on iequidistant and non-equidistant tooth profile，and the non-equidistant profile was proved to be better.As the spiral bevel gear geometry is complicated, material flow difficultly during hotforging. The shape of billet plays an important role on the full of the tooth form. Cyclic billetwas adopted to produce spiral bevel gear. By using Deform-3D software, several differentcone angles of billet were studied. Through analyzing the simulation results, the best coneangle was determined. Reference on the study of straight bevel gear tooth profile, this article did some researchon spiral bevel gear and made equidistant tooth profile and non-equidistant tooth profileschemes. By analyzing the material flow and folding defects during the cold finishing, theinfluence of hot forging tooth profile on surface roughness was summed up. Non-equidistanttooth profile was proved to be better than equidistant profile by process test.