Abstract:
The method of regarding corn seed as bullet to sow is a new way, which can realize mechanically directional sowing of corn. The concrete realization process is as follows: Firstly, it needs to make directional corn seed bullet clip, and then the corn seed in the bullet clip is inserted into the soil by specific equipment. The key technology of making directional corn seed bullet clip is directionally pushing corn seeds. In order to realize directionally the pushing of corn seeds, taking dent corn seeds with horizontal posture as research object, most tip orientation of which had been oriented by existing directional device, in this paper, a directional push device for dent corn seeds was designed. Those dent corn seeds could be directionally received, then directionally moved and pushed by the device. The device consisted of 3 parts: directional receiving and moving mechanism, directional pushing mechanism, and power unit. Among them, the directional receiving and moving mechanism was mainly composed of a turntable, 4 seed holders, a turntable base and other components. The directional pushing mechanism mainly consisted of a cam, a linear push rod and some others. And the power unit was a simple stepper motor system. There were 2 kinds of stations when corn seeds with horizontal posture got into the seed notch on seed holder: tip facing forward or main part facing forward. The working process of directional push device for corn seeds was as follows: The turntable started to rotate after corn seeds got into the seed notch, taking seed holders and corn seeds turning together on the turntable base. The corn seeds with main part facing forward would be eliminated when the seed holder passed through the sorting notch, and the corn seeds with tip facing forward could be passed through smoothly, thus completing the directional receiving of the corn seeds. The turntable continued to rotate, and the corn seeds held were kept relatively fixed with the seed holder under the constraint of guard board, and the turntable stopped after turning 90°, thus completing the directional moving of the corn seeds. At last, the linear push rod would push each seed in seed holder outward to complete the directional pushing function. Among the 3 functions of the directional push device for corn seeds, the directional receiving function was the most critical, as it provided a basis for directionally moving and pushing. The analysis of the principle of directional receiving function showed that the shape parameters of the sorting notch had great influence on the process of directionally receiving. Taking arc angle and depth of sorting notch as factors, and respectively taking holding success rate of corn seeds with tip facing forward and elimination success rate of corn seeds with main part facing forward as test index, 2 simulation tests were carried out with corn seeds of 2 different stations. The best parameters of the sorting notch were obtained: Arc angle was 14° and the depth was 3 mm. Under this condition, the holding success rate and elimination success rate respectively reached 94% and 100%. In order to verify the accuracy and reliability of simulation optimization result and test the performance of the device, the practical directional push device for corn seeds was constructed. A performance experiment was performed with 600 corn seeds whose most tip orientation had been oriented. The results show that the device works stably, and the 3 functions of directional receiving, moving and pushing perform well. For directional receiving function, the holding success rate of corn seeds with tip facing forward and elimination success rate of corn seeds with main part facing forward are respectively 93.8% and 100%, which coincide with simulation very well. Generally, this research provides a reference for mechanically making directional corn seed bullet clip subsequently and mechanically directional sowing of corn.