Precision Plastically Molding Process Research Of Automobile Driving Spiral Bevel Gear Blank Based On Numerical Simulation

The automobile rear axle spiral bevel driving gear have a complex working environment. The number demand of the automobile rear axle spiral bevel driving gear is one of the most during the car parts.Spiral bevel gears is one of the most easily damaged place,the other is the position of the connection of cone and slender shaft.Currently,it’s difficult forging driving spiral bevel gear,the forging technology is still on research stage,so forming driving spiral bevel gear by cutting still is the main way.Following are the most important factor affect the quality of driving spiral bevel gear:Cutting Parameters,Cutting Tool&The quality of gear blanks.In order to improve the quality of driving spiral bevel gear and cut costs, this article focus on research all kinds of molding process of driving spiral bevel gear blank and make the DEFORM as the primary tool.According the result of numerical simulation analysis Metal flow process, Stress and strain, Mold load& Breakage during the forming process.Selecting suitable equipment according the forming force and forming characteristics of each process.Through the study found,there are a series of defect on the surface of cone large end using ordinary tie wedge of cross wedge rolling rollformability driving spiral bevel gear blank,such as:fold, overlap, severely burning. The damage value in the cone and elbow junction is larger. In the molding process, fold and overlap were crushed into the cone and elbow junction, this makes Internal organization of the cone and elbow junction destroyed and generated stress concentration. In order to improve these problems as much as possible,this article modify the vertical side end surface of tie wedge to inclined side end surface and filleting the cutting edge of tie wedge.The experimental results of finite element simulation show that metal flow more smoothly and substantially eliminated fold on gear blanks cone big end surface during forming process. At the same time, damage value of product reduced a lot and the quality of gear blanks improved a lot.Using Cross Wedge Rolling-Vertical Forging method forme driving spiral bevel gear blank,in order to saving raw materials and improve material utilization the larger diameter portions is placed at both ends during cross wedge rolling what is used shaping shaft portion.The cone of gear blank forming by vertical forging,so the dimensional accuracy and quality of driving spiral bevel gear blank better than cross wedge rolling.However,gear blank affected by former cross wedge rolling process,there is a pit need to be filled during vertical forging.So the forming force is bigger and only generate overlap firstly can fill the pit later.However,using Extrusion-Vertical forging forming driving spiral bevel gear blank there isn’t pit generate and need filled.This artical research the forming effect of two kinds of temperature, they are thermoforming the billet molding temperature higher than 900 ℃ and cold forming the billet molding at room temperature.The quality of the gear blank is the best among the three kinds of molding process.Dimensional accuracy of gear blank is the highest and it’s damage value is the smallest.But affected by characteristics of extrusion technology the production efficiency is the lowest.From the result of research,no matter the Cross Wedge Rolling-Vertical Forging or Extrusion-Vertical forging, vertical forging process not only forming gear blank’s cone but also played an important role of finishing and straightening.