Theoretical Analysis And Experiment Study On Maize Pair Seeds Thresher

Maize is China's main grain crop, feed and industrial raw materials, which has an important position in national economic development. To enhance the maize production and to improve the total yield as soon as possible have a great significance on the national food production. The maize ear has the feature of pair seeds. The pair seeds cultivation technique, based on this biological properties, is a new type of maize high-yield cultivation techniques. Through the experiment, we can find that the maize grown from pair seeds is identical in biological properties and can produce fruit normally. In this way, the yield increase by 15%～20% with the same acreage. The maize pair seeds thresher is the key device for maize pair seeds cultivation techniques. Experiment for it has practical significance.Based on the review status and research progress of maize thresher, the maize pair seeds thresher was analysed theoretically and the key parts were designed. The key parts of maize pair seeds thresher mainly contained coil compression spring, grip-feed apparatus of double rollers, drill fixed apparatus and drill. Done with the design, the experimental studies were tested about the thresh parameters. The single factor tests and the quadratic orthogonal tests were experimented, and the effect on thresh percentage of pair seeds and damaged seeds of maize ear average diameter, maize ear average water content, thresher drilling tool diameter and drill angle was analyzed. The mathematical model was developed and the test parameters were optimized. The major conclusions were as follows:(1) Theoretical analysis of the pair seeds thresher. The maize pair seeds thresher relied on a set of system of power transmission and deceleration, which adopted the inner-thresh principle. The maize ear was broken from inside, and the pair seeds were taken down from the spikelet primordial. From the machine structure, the maize ear was clamped by the pair rollers and was affected by static friction of flexible rubber belt through the process of feed, transfer, access to the drill and drill.(2) Design of pair seeds thresher's key parts. The main geometric parameters of the coil compression spring were determined. The pitch was 3.68mm, the external diameter was 18mm. the inner diameter is 12mm, the height is 70mm.The key part of the grip-feed apparatus of double rollers was flexible rubber rape. The neutral axis of the maize ear and drill was ensured and the goal of reducing the breakage of maize ear was achieved by adopted the rubber rape. The drill fixed apparatus contained drill base and drill sheath. The two parts must be matched exactly, and then the stability of the drill's high speed process could be guaranteed. The drill contains drill edge and drill stem. The drill edge must be guaranteed a certain degree and angle to cut.. The drill stem and the drill fixed apparatus must be matched exactly. (3) Experiment of pair seeds thresher. The significant factors such as drill angle, thresher drilling tool diameter, maize ear average diameter and maize ear average water content were determined by single factor tests. Under the premise of the bulk of the maize ear down into the hopper, the drill angle was 60°and the ear average water content was 35%, a high percentage of pair seeds can be achieved.(4) Quadratic orthogonal experiment of pair seeds thresher. The mathematical model was developed. The optimal parameters of thresher were obtained through multi-goal non-linear optimizing method. When the average diameter of maize ear is 39mm, the ear water content is 44% and drilling tool diameter is 23mm and its angle is74°. When the maize ear average diameter is 42mm, the ear water content is 44% and the drilling tool diameter is 24mm and its angle is 72°. When the maize ear average diameter is 47mm, the ear water content is 44% and the drilling tool diameter is 25mm and its angle is 70°.