Study On Corn Snapping Mechanism With Mode Of Bending And Breaking

Study on Corn Snapping Mechanism with Mode of Bending and BreakingAfter many years’ development, corn has become the second largest crops after riceand the main force of grain production in china. Because of the high loss rate caused by thecorn snapping device, poor stability and adaptability and agricultural machinery which arenot adapted to agronomic, the mechanized level of corn harvesting is only25%at present.Compared with the wheat harvest and the rice harvest, it is obviously not high. Therefore,accelerating the development of corn-harvesting mechanization grows urgent. The traditionalcorn pick spike takes advantage of the stretching and extrusion action between the cornstalks and the corn ears, its’ working principle inevitably resulted in destruction to the cornears. It is not beneficial to the recycling of the complete corn stalks too. For these reasons, inorder to improve the quality of corn ear, reduce the damages to corn in the process ofmechanical harvesting and take the recycle of the corn stalks into account, a new principle ofcorn harvesting should be explored.For the purpose of reducing the damage to the corn in the process of mechanicalharvesting, the study uses the snapping mechanism of bending-breaking to improve andoptimize the traditional snapping device. The following is the main contents of the study:1.From the measurement data of the physical characteristics of corn plants，the linearrelationship has been found between the height of the corn plant and the height of the cornear. According to the linear relationship, the determination of the snapping rolls’ positionbecomes easier.2. From the determination of mechanical properties of corn, the study discovered a linearrelationship between tensile strength and displacement change in the process of tensilefracture and bending broken, and the strength of bending broken is less than the strength ofthe tensile fracture.3. Based on the test to the reasonable structure of the pick spike roller, a new simulationmodel was established and the simulation analysis on the corn snapping mechanism wasfinished. Thus it can be seen that when the diameter of the pick spike roller is200mm, thedistance from the contact point of snapping rolls and corn ear to the root of the corn ear can not be less than30mm. If it is less than30mm, it may cause impaction to corn straw fromsnapping rolls in the process of snapping. In serious condition, it can put corn straw broken.When the peripheral velocity is0.4m/s and the conveying speed of the gripping chain is0.6m/s, the resultant velocity of the corn ear is561m/s at the contact point to the pick spikeroller. The resultant velocity is slightly less than the conveying speed of the gripping chain.It may be relation to the friction to the corn ear from the snapping rolls and the clampingmechanism.4. The optimum technology conditions were selected by orthogonal test consisting of threefactors which are respectively at three different levels, the results shows that the relativeposition of the snapping gap is230mm, the transfer speed of the support chain is0.4m/s andthe rotation speed of the snapping rolls is450r/min.