Research On Cold Extrusion Forming Precision Of Truck Gear

Spur gears are the most common form of transmission parts in automobile and machinery industry.It has an irreplaceable role in the industrial production.At present,spur gears is mainly processed by adopting the method of traditional rolling teeth and gear shaping.Machine tool machining inevitably exist a long processing time,more cutting waste,tool wear fast and a series of problems.Cold extrusion technology is a kind of high efficiency and low consumption plastic forming method.Using the cold extrusion process to processing gear can not only avoid the shortage of the machining process,but also will obtain higher parts strength and good surface quality which result by continuous gear internal organization streamline and the surface no cutting marks.With the development of cold extrusion technology,gear which Using for a certain range are more and more processed by this net forming method.Because of the complexity and uncertainty of the metal flow during the process of gear extrusion,the cold extrusion forming quality and forming precision of the gear can't meet the job requirements,which severely restricted the promotion of cold extrusion technology.Therefore,how to improve the forming quality and forming precision of the gear is the key to formulating of the cold extrusion process.In this article,the wheel reducer planet gear of truck is the research object,according to the structure characteristics of the spur gear,proposed continuous extrusion + cold finishing forming process.The forming process of gear are analyzed by numerical simulation.The metal flow law and the distribution regularity of stress and strain in the forming process of gear were studied.Determined the specific influence of technological parameters,which for the forming quality of gear.Studied die elastic deformation and extrusion elastic recovery in extrusion process.To ensure the tooth profile precision of gear,mold modification method is proposed.For improving the gear direction precision,the approach of cold extrusion + finishing was put forward.Studied metal deformation behavior of cold finishing process,the change law of gear direction precision in the finishing process were analyzed.According to the results of numerical simulation,spur gears continuous extrusion and cold finishing process test were carry out.The results show that reasonable die structure parameters can ensure forming quality and forming force can be effectively reduced at the same time.The modification of extrusion die can ensure the tooth profile precision of coldextrusion gear.Cold finishing process can improve the gear direction precision.Test results show the validity of the numerical simulation results.