小麦播种机开沟器双向平行四杆仿形机构的设计及运动仿真

    Design and motion simulation of opener with bidirectional parallelogram linkage profiling mechanism on wheat seeder

    • 摘要: 寒地冬小麦一般在秋季作物的垄沟两侧进行播种,为了保证冬小麦开沟器不到垄台上伤害正在生长的农作物,该文设计了双向仿形平行四杆机构。该文对仿形机构进行受力分析,确定了影响仿形性能的各参数;根据初始工作角和最大下仿形量,设计出仿形杆的长度为386.37 mm,最大上仿形量为98.35 mm;在左右达到最大仿形量时,确定左右仿形角为15°。最后应用CATIA软件进行运动仿真分析,通过运动仿真表明,仿形机构可实现上下、左右仿形,上下仿形量可达到170 mm,左右仿形量可达到100 mm,满足理论设计的双向仿形量。该机构为研制冬小麦免耕播种机提供了依据。

       

      Abstract: Abstract: Heilongjiang province is located between north latitude 43°25′~53°33′ and east longitude 121°11′~135°5′. There is one ripe area in a year at lower temperature, therefore the soil is ridged. In order to meet the wintering requirements for winter wheat, the seed must be sowed in late August and early September. As the previous crop is still growing, winter wheat is sowed at both sides in the furrow. In order to protect the growing crops on the ridge, parallelogram linkage mechanism must simultaneously achieve upper and lower, left and right profiling. Existing parallelogram linkage mechanism had achieved up-and-down profiling, so bidirectional parallelogram linkage profiling mechanism was designed, which consisted of the frame, latitudinal profiling bar, longitudinal profiling bar, and limiting rack. Latitudinal profiling bar was mounted in a sleeve of the frame and it could rotate relative to the sleeve. Latitudinal profiling bar connected longitudinal profiling bar through the connector, and they could not move separately, but could only rotate relatively to the frame as a whole. The longitudinal profiling bar rotated relative to the connector. The rotating angles of latitudinal profiling bar and longitudinal profiling bar were limited respectively by limit rack which was installed in the monomer beam. When the seeder was operating, latitudinal profiling bar rotated relative to the sleeve and longitudinal profiling bar rotated with it, so the seeder monomer achieved up and down profiling. When the longitudinal profiling bar contacted the horizontal beam of limit rack, the rotation was stopped. In this case, the seeder monomer reached the limited location of upper and lower profiling; longitudinal profiling bar rotated relative to the connector at the same time, the seeder monomer achieved left and right profiling. When longitudinal profiling bar contacted the vertical beam of limiting rack, the movement would be stopped. In this case, the seeder monomer reached the maximum of left and right profiling. The profiling performance parameters were determined through force analysis. According to the initial angle and maximum of lower profiling, the parallelogram linkage ' length was 386.37 mm and maximum of upper profiling was 98.35mm. The left and right profiling angle was 15° when left and right profiling reached their maximum. Then the motion simulation analyzed profiling mechanism with CATIA. The results indicated that simulation trajectory was close to real field situation. Maximum of upper and lower profiling reached 85 mm respectively and the left and right profiling reached 100 mm. The parallelogram linkage mechanism has the advantages of simple structure and better profiling results. The realization of this mechanism has an important significance for the research of winter wheat no-tillage seeder.

       

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