Design Of Harvest Ditch And Stalk-Disposing Machine

In solving the problem of straw burning practices, a consequence from labor shortage during the harvesting and sowing season in rural regions, and which results into the waste of energy resources and a potential pollution to the environment, a combined harvester was designed by combining the functions of the cereal crop combine harvester and the ditches. The main purpose of the machine was to facilitate ditching and stalk-disposing while performing harvesting, so that the two-pass field operation of harvesting and ditching and stalk-disposing was avoided. The main achievements include:The prerequisite for ditching and stalk-disposing was the proper ditching. While the quality and the uniformity of the ditching operation was related to the structure and operational parameters of the ditcher. If the disc adjustment height satisfies the operational demand of the multi-function harvester, the objective of the machine design turns out to be the minimum material used and the lowest cost of the production. Therefore the objective function of this work was designed as the maximum adjustment height of the disc, the minimum disc size and the least displacement of the hydraulic cylinder. These resulted into a optimization function for the ditcher, which, was further calculated in Matlab to yield the sizes for the minimum disc size, the maximum displacement of the hydraulic cylinder and the maximum adjustment height of the disc to be885mm,182mm and850mm, respectively.To fully exploit the power transmission of each level and to reduce the size and the mass of the chain system for a stable, simple and flexible working condition, a optimization model was proposed by extensively approximating the transmitted power [P] by each level to the calculated power Pj. This optimization determined the power transmission ratioes for the first and the second level to be1.78and1.42.The operational efficiency and the quality of the multi-function harvester was mainly influenced by the condition of whether the power system was compatible and if the harvesting and the ditching assembles were synchronous. Thus the power consumption of the harvesting and the ditching parts were studied and based on which a mathematical model of the overall power demand by the machine was provided, which could be applied on all similar models.With an aim of reducing the cost of machine production and experiment and to reduce the development cycle of the model machine, as well as the improvement of the visibility, the Pro/E development software was used to generated the3-D models of the ditching and power transmission mechanisms. The developed model was further simulated in the ADAMS to test the correctness of the movement of the ditching parts.On the basis of the design, the parts of the ditching and its power transmission assemblies were produced and assembled. Field test on the machine revealed that, by attaching the ditching parts on the harvester and moving in a reversible direction, very little soil was observed falling back into the trapezoid ditch. The generated ditch allowed the stalk to be collected in and the field well drained. As each part of the machine were well synchronized, the overall working efficiency and the ditching parameters were proved to be satisfactory. If no modification was made on the power (46kW) the revised harvester gave a lower harvesting efficiency, but a higher composite working efficiency when the once-over field operation was considered as compared with the stepped field work of harvesting and the ditching for stalk-disposing.