Research On The Key Technology Of Cold Forging Of Spur Gear

Spur gears with complicated shapes are important driving parts which are broad used in mechanical industry. Therefore, high material quality, dimension precision, surface quality and combination mechanical properties should be attended. The extrusion technique become a trend towards spurs gears for it has many advantages, saving material, high productivity, high precision of parts dimensions, good parts surface and high product quality .The cold forging of spur gear belongs to the complicated three dimension deforming. The billet's flowing is very complex during forming process, and it has multi factors which can influence figuration and precision of the spur gear. In this paper, we proceed with the cavity die which is the key part of the formed part, with a view to the two key problems which are assurance of full of the tooth form and depress the forming pressure, make an offer of designing thought of an extrusion transition cavity to conform to the rule of metal flowing deformation and a new craft thought of extrusion from two sides; Based on the advanced three-dimensional designing software, CATIA V5, we achieve the sculpt work of extruding cavity and forming cavity, and with this software we analysis the stress and strain of extruding cavity, at the same time forecasting the defects which may arisen; Putting forward the thought that modifying the dip of the male die's end face can enhance the radial filling of the gear form; Applying the cold forming theory, we design the cold extrusion forming craft and die structure logically, and in the virtual reality we accomplish the geometric modeling of die structure and analysis the assemble character and static state interference; At last we build the unit store of the die parts.This paper brings forward some visualized designing thoughts and improvements combining the cold forging theory of spur gear and the developing trend of recent period's CAD/CAM, and we believe that these thoughts and improvements will play a positive role in developing the precise form of spur gear.