履带式油菜苗移栽栽植孔成型机的设计与试验

为设计新型油菜移栽机,基于旱地移栽作业的工作特点,融合油菜移栽农艺要求,研制了一种履带式油菜移栽栽植孔成型装置。通过分析土壤物理机械力学特性,求取打孔机构垂直出土所受摩擦阻力参数方程,为关键部件打孔机构的机构设计提供力学参数与理论依据;完成关键部件—打孔机构、靠模凸轮进行设计及优化后,设计并试制试验样机,进行田间试验。试验结果表明:机器以慢一档工作状态下前进速度为1.65~1.78 km/h,作业效率达到0.231~0.249 hm2/h,其成孔的平均合格率也达到93.8%。研制的机器能形成满足设计要求的栽植孔,为新型移栽机的设计提供技术支持。

Design and experiment of planting hole forming device of crawler transplanter for rape (Brassica napus) seedlings

Abstract: In order to resolve some key issues about the machinery of transplanter for rape seedlings, a new type of transplanter with crawler planting hole forming tools for rape was designed based on the working characteristic in the dry land and agronomic requirement. Research on soil physical and mechanical characteristics were conducted to provide the technical parameters for the design of the hole forming device. First, we completed the whole structure design and analyzed the working principle of the device. The crawler was drove by power system to go forward, on which the hole forming device was installed and synchronously moving. The surface cam was mounted on the chassis. As the caterpillar moved forward, the pore forming device installed on the track vertically stabbed into the soil under the pressure of surface cam supplied by body weight. As the tracks moved forward, the hole forming device was out of the surface cam profiling. As such, a plant hole was formed. We analyzed the curve of surface cam limit, confirmed the limited point so that a coordinate system was established. We then chose the definition curve interpolation method to solve the parameter equation of surface cam profiling combining with Matlab7.0 software plot function in the program and generated surface cam outline curve. For the optimization of punch mechanism of structural design, the surface cam profiling and reset spring control capacity into hole device unearthed vertically. The cylindrical hole was pressured by shearing and extrusion soil. We analyzed the same track number, it had two tracks. Each of them had two linear holes. When the machine moved forward, each side could dig holes in four rows at one time. We installed rolling bearing in the hole forming device for rolling friction instead of sliding friction to reduce friction in the cylindrical hole and the friction between the surface cams. By use of the prototype machine in field, we recorded variables, such as the time, moving distance, distance between holes, the depth of effective planting hole, and the diameter of planting hole. We analyzed indexes such as the rate of qualified hole, hole forming frequency, efficiency, etc.. The result showed that if the machine at lower speed at 1.65-1.78 km/h, the efficiency was up to 0.231-0.249 hm2/h, and the rate of qualified hole up to 93.8% on average. The various performance indicator met the design requirement. The planting and hole forming machine can get holes at 1800 mm in length each, 50 mm in diameter, 50 mm in depth, and 120000 holes/hm2 in hole density per area. This could get the planting hole to satisfy agronomic requirement. The research provided theoretical and technical references for design of the new type of transplanter.