Research on Optimum Design of Plantary Gear Transmission Mechanism for Cutterbar
|School||Northwest University of Science and Technology|
|Course||Mechanical Design and Theory|
|Keywords||transmission of cutter bar planetary gear transmission optimization design simulation finite element analysis|
Cutter bar transmission which performance capabilities have a direct impact on the combine harvester work quality and efficiency is the important component of combine harvester. The crank pin institutions and pendulum institutions are widely used on the domestic combine harvester at present. But these institutions has common drawbacks that they may lead cutter bar damage by vertical force or horizontal force. In contrast, the planetary gear transmission which can avoid vertical force or horizontal force has advantages of less abrasion, smart structure, and higher reliability. In conclusion, It is a trend that the planetary gear transmission replaces pendulum transmission. So far, planetary gear transmission which only adapted in the Deutz-Fahr combine harvester is rarely involved in the researching and design. Therefore, it is very necessary to do research and design on planetary gear transmission.Aim to avoid the drawbacks of cutter easily broken and reduce vibration because of vertical force or horizontal force, the paper designed planetary institutions using optimization designing methods , completely analyzed and verified the plausibility and reliability of the planetary institutions.Using the optimize toolbox of Matlab software, the planetary transmission was optimum designed. Under the help of the Pro/E ,a famous modeling software, 3d model was created ,virtually assembled and dynamics simulated according to the optimize parameters. To verify the reliability of the design, static analysis was conducted in accordance with the actual conditions in Ansys software.The dissertation consists of the following contents and results:(1)Taking Dongfanghong 4LZ - 2.5 combined harvesters as an example , analyzed the motion law of pendulum ring box transmission mechanism, and the motion law of the planetary gear transmission mechanism. Obtained the parts size conditions which meet the reciprocating linear motion.(2)Established the mathematical model with the most compact in structure for target and the size to realize cutter bar movement,the rules of planetary gear design, the rated capacity as the constraints . (3) Calculated the results using Matlab GA optimization Tool-box and get the optimization parameters according to the actual situation.(4) Created three-dimensional models and parts of virtual assembly by Pro/E software to verify the correctness of the component size. Completed movement simulation function to get cutter bar movement curve. Compared with the pendulum institutions movement to verify the rationality of design .(5) Verified the correctness of the optimization design result by the finite element analysis for bending strength, according to the planetary gear transmission mechanism in low speed and heavy work conditions.The results indicate: the movement of the optimization design planetary gear institutions was simulated by Pro/E software which shows its movement character near to pendulum institutions, and finite element analysis of the bending stress shows the designed planetary gear institutions meet the required strength , it is concluded that its design size is feasible. After a series of CAD, CAE technology design, it is proved that the designed planetary gear transmission has good work performance and reliability.Then it improved the force situation and avoid the problem that cutter bar break,which improved combine harvester work efficiency.