冷浸田立式锥辊主动挤压沟垄定型装置设计与试验

    Design and experiment of the upright cone roller active extrusion ridge and furrow shaping device for cold waterlogged paddy field

    • 摘要: 针对传统开沟起垄装置在土壤黏重、湿度大的冷浸田条件下作业面临沟垄难以定型、沟型稳定性较差等问题,该研究采用先旋耕起垄再二次主动挤压的作业方式,设计了一种立式锥辊主动挤压沟垄定型装置。根据土壤挤压和沟垄定型原理,对厢面压辊和立式锥辊结构参数进行了优化设计,对机具前进速度、沟垄定型装置转速及旋耕刀轴转速进行了合理匹配。通过单因素试验明确了土壤含水率、垄体角度和机具前进速度对沟宽和垄高稳定性的作用规律;通过EDEM仿真,以机具前进速度、沟垄定型装置转速和旋耕刀轴转速为试验因素,以沟顶宽稳定性系数和土壤回流率为评价指标,进行了二次正交旋转组合试验,得到较优参数组合,即当机具前进速度为0.56 m/s、沟垄定型装置转速为92.25 r/min、旋耕刀轴转速为194.56 r/min时,沟顶宽稳定性系数为93.52%,土壤回流率为6.75%;田间试验结果表明,主动挤压沟垄定型装置作业后垄高为186 mm、沟顶宽为351 mm、垄顶宽为1710 mm、微沟宽为45 mm、微沟深为22 mm;垄高、沟顶宽、垄顶宽、微沟宽和微沟深稳定性系数分别为95.36%、91.90%、92.65%、96.52%和95.77%,其中沟顶宽稳定性系数与仿真结果基本一致;相比于传统开沟起垄装置作业效果,垄高、沟顶宽和垄顶宽稳定性系数分别提高6.90、7.78和6.88个百分点。各项指标均满足冷浸田机械化沟垄定型作业要求。

       

      Abstract: Cold waterlogged paddy fields can be characterized by the heavy and humid soil. The challenges remain to form the well-defined ridges and furrows. However, the traditional ridging and furrowing apparatuses cannot fully meet the large-scale production using the relatively low stability of furrow configurations. In this study, an operational approach was proposed as the initial ridging of rotary tillage, followed by the secondary active extrusion. Consequently, a ridge shaping device was devised with the vertical conical roller using active extrusion. The structural parameters and installation positions of the device were determined during operation, according to the soil extrusion and ridge-furrow formation. Additionally, the force analysis was conducted on both the compartment surface pressure roller and the vertical conical roller. An optimal matching was established for the forward velocity of the machinery (ranging from 0.56 to 1.11 m/s), the rotational speed of the furrow and ridge shaping device (70 - 130 r/min), and the rotational speed of the rotary tillage cutter shaft (120 - 220 r/min). The experiments of soil bin were carried out to clarify the effects of soil moisture content, ridge angle, and tool forward speed on the stability coefficients of furrow width and ridge height. The combination of parameters was achieved in the soil moisture content of 32.97%, the ridge angle of 60°, and the tool forward speed of 0.56 m/s. A virtual soil trough was constructed with the machinery forward velocity and the rotational speed of the ridge-furrow shaping device. A quadratic, orthogonal and rotational experiment was carried out, taking as the rotational speed of the rotary tillage cutter shaft serving as the experimental variables, and the stability coefficient of the furrow top width and the soil backflow rate as the evaluation criteria. Variance analysis and regression equation analysis were then performed for the stability coefficient of the furrow bottom width and the soil backflow rate, followed by significance testing. A nonlinear mathematical model was established after optimization, according to the agronomic requirements of cold-soaked fields and the actual operations. The optimal combination of parameters was obtained after optimization in Design-Expert 12 software: A tool forward speed of 0.56 m/s, a ridge shaping device rotation speed of 92.25 r/min, and a rotary tiller blade shaft rotation speed of 194.56 r/min. Under these optimal working parameters, the stability coefficient of the furrow top width was 93.52%, and the soil return rate was 6.75%. The field furrow and ridge shaping trials were implemented to validate the operational performance of the active extrusion furrow and ridge shaping device. The results reveal that the ridge height was 186 mm, the furrow top width was 351 mm, the ridge top width was 1 710 mm, the micro-furrow width was 45 mm, and the micro-furrow depth was 22 mm after operation. The stability coefficients of the ridge height, the furrow top width, the ridge top width, the micro-furrow width, and the micro-furrow depth were 95.36%, 91.90%, 92.65%, 96.52%, and 95.77%, respectively. Notably, the stability coefficient of the furrow top width was better in line with the simulation. Compared with the traditional ridge and furrow device, the stability coefficients of the ridge height, the furrow top width, and the ridge top width were increased by 6.9, 7.78 and 6.88 percentage points, respectively. All of the indices were fully met the requirements for the mechanized operations of furrow and ridge shaping in cold waterlogged paddy fields.

       

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