Optimization Design On Transmission Box Of Hand-held Rice Transplanter

The hand-held rice transplanter is the main machine of rice planting in our country at present, which require light weight, high strength and small size, in order to adapt to the muddy field, and avoid the wheel sunk deep into the gravel mud, Transmission is the heaviest component beside engine in the chassis of hand-held rice transplanter; in addition, design and produce the transmission also need high technical requirements. For a long time, it appears to be lack of theoretical study on transmission of hand-held rice transplanter in our country. Designing by experience bring serious impact on hand-held rice transplanter to raise the level of technology. In this article, the research object is a common six gear transmission of hand-held rice transplanter; Combined with advanced simulation and analysis tools to optimize the structure of transmission’s box; Proposed a design idea by using the dynamics simulation and finite element simulation analysis, by using this method to make strength analysis of transmission’s box, according to the analysis results of structure strength analysis to make the topology optimization. The main content of the thesis is as follows.1)Have a study of technology status and development of rice transplanter and transmission; make an analysis of the existing design problems of transmission in the hand-held rice transplanter, the main research contents of this paper are presented.2) By the method of three coordinate measurements, mapping the major component of common six gear transmission of hand-held rice transplanter, such as box, shaft, and gear; by using 3D drawing software Pro/E to build up the model of transmission box.3)Using the finite element analysis software HyperMesh to modeling the transmission box accurately, have an analysis of free mode and constrained mode, the dynamic characteristic and the weak link of the box body are analyzed by means of the vibration model. The study indicates that; the natural frequency of the transmission completely evades the vibration frequency of the engine.4) By using the method of experimental modal analysis to measure the test modal of transmission box, compared test modal frequency with free modal frequency, verifying the model of transmission box which build up by HyperMesh is reasonable.5)Build up a virtual kinetics simulation model to gear transmission by using Adams. Add to output torque, and measure the force of shaft end, get the support reaction of bearing block.6)By using the destiny structural topological optimization to make topology optimization of transmission housing, based on the method make sure structural stiffness and local stresses, having redistribution of structural material and redesign strengthening rib. After redesign the housing’s weight is 20.17 Kg, which is reduced 6.5% compare with before.The strengthening rib which are added to the area of bearing block of shaft number 4 reduce the focus stresses, and increase structural strength of the transmission housing.