Research On Process Improvement And Fatigue Life Of Precision Rolling Forging Of Truck Front Axle

With the advancement of economic construction,the demand for commercial trucks in China has increased significantly and the market prospects are broad.As the important carrier of the truck,the front axle is in a very harsh environment.It is subjected to alternating stress,moment and deformation force during the running of the vehicle.Especially when the truck is under heavy braking,the front bearing is subjected to the total load of the truck.More than 70%,so there is a high demand for the strength and fatigue life of the front axle.The shape of the front axle is relatively complicated,and the cross-section fluctuation is large.It is a long-axis type component with a high forging coefficient.The front axle is produced by precision roll forging-integral die forging process,which reduces the forming load of die forging and reduces the investment of die forging equipment.However,the existing roll forging theory cannot accurately and accurately design the mold,which makes it difficult to repair the roll forging die during the test.The accuracy of the roll forging die after repeated modification is greatly downloaded,and the front axle roll forging stability is deteriorated,resulting in the front axle.Produces more quality defects.In this paper,the front axle of a certain type of truck is taken as the research object,and a series of quality problems generated during the forming of the original process are studied based on finite element and reverse engineering techniques.Has the following work:(1)Design based on negative tolerance: For the problem of size deviation of the front axle,the idea of negative tolerance design is proposed,and the precision of the front shaft precision roll forging process is redesigned by reducing the original blank size,and the roller with reasonable metal distribution is obtained.Forging blanks improve the stability of billet metal roll forging.Finally,the feasibility of the process improvement is verified by physical experiments.The final forging of forgings is full and flawless,and the forging dimensions meet the design requirements.(2)Based on reverse engineering technology,precision roll forging die design: For the front axle roll forging die profile is complex,the debugged die profile can not be accurately reflected on the original design of the digital die,for the later die maintenance,repair Cause difficult problems.The reverse engineering design of the front axle roll forging die is carried out by reverse engineering technology.The mold cavity is parameterized and processed by CNC machine tool.Finally,through the physical test,the first test die is successfully produced to produce the qualified front axle forging,and the front axle roll forging die is realized.Precise design.(3)Front axle fatigue life study: The fatigue performance of the truck front axle was evaluated by the fatigue bench test,and a series of experimental studies were carried out on the early failure front axle specimen.From the aspects of surface quality and internal quality,the factors affecting the fatigue life of the front axle forgings were studied.The causes of the influencing factors were analyzed in combination with the actual production,and corresponding improvement measures were proposed.Finally,the fatigue life of the front axle was effectively improved.