Theoretical Analysis And Experimental Research On Orbital Head Trajectory And Forming Force Of Orbital Cold Forming Press

With the vertical orbital cold forming press possessing four types of orbital head movement trajectories including circle, straight line, spiral line and multi-branches rose curve as the research object and according to the problem that the movement trajectories of straight line, spiral line and multi-branches rose curve cannot achieve continuous local forming, this thesis puts forward the new type of orbital head movement trajectories of ellipse,spiral line and multi-branches rose curve without going through the center. Based on the theoretical research and experiment of cold orbital forming force, it carries out in-depth research on the impact exerted on orbital forming force by orbital head angle, forming process of different movement trajectories of orbital head. The research on this subject will be conducive to solving the problems including few application of straight line trajectory of orbital forming press, no actual application of trajectories of spiral line and multi-branches rose curve, providing theoretical basis for improvement of orbital head structure, designing new type of orbital forming press and development of cold orbital forming technology.Based on the analysis of orbital head structure and movement principle of the vertical orbital cold forming press, it establishes orbital head movement equation, deduces the formation mechanism and rules of circle, straight line, spiral line and multi-branches rose curve. Through analyzing the characteristics of four movement trajectories of orbital head, it establishes the function relationship between the orbital head angle and the inner, the outer eccentric sleeve angle, puts forward the new type of orbital head movement trajectories,conducts theoretical analysis of its motion equation and law, and demonstrates the feasibility argumentation on the improvement of the orbital head movement mechanism. The new type of orbital head movement trajectories has avoided the trajectory center point and can realize continuous local forming in the forming process, reducing orbital forming force and improve the stress state of the orbital head.Through analyzing the influencing factors and stress of cold orbital forming and according to the problem that when orbital angle of is small, the calculation error of orbital forging contact area is large, resulting in the inaccurate calculation of orbital forming force, it deduces calculation formula of the contact area of orbital forming again and carries out checking, constructs the relationship between orbital forming force and technological parameters, improve the theoretical calculation formula of orbital forming force, providing a theoretical basis for the analysis of the orbital forming force of different movement trajectories.Based on the development of 2000 kN vertical orbital cold forming press, with flange parts as the testing object, it carries out orbital forming experiments when the orbital head adopts circle movement trajectories under different orbital angles, it collects the change data of orbital forming force, simulates orbital forming process with Deform-3D finite element,analyzes and verifies numerical simulation results and the computational formula of orbital forming force and obtain the relationship chart between orbital head angle and orbital forming force, providing a theoretical basis for parameter selection improved by movement trajectories.It establishes the equation of three-dimensional movement trajectories of orbital head, carries out simulation on the three-dimensional curves in the process of orbital forming with MATLAB software, conducts theoretical analysis of the orbital forming process curves of different movement trajectories, and also analyzes the laws and characteristics of the forming process before and after the improvement of movement trajectories combined with movement trajectories orbital forming experiments of circle,straight line, spiral line and multi-branches rose curve.This thesis establishes orbital head movement equation, the function relationship between the orbital head angle and the eccentric sleeve angle and theoretical calculation formula of orbital forming force, analyzes the formation mechanism and rules of the movement trajectories before and after the improvement of the orbital head. In addition,through theoretical analysis, simulation research, comparison and verification of forming experiments, it obtains the relationship between orbital head angle and orbital forming force as well as the orbital forming process curves and characteristics of different movement trajectories, demonstrates the advantage of the improved movement trajectories.