水稻秸秆反旋深埋滑切还田刀优化设计与试验

针对水稻秸秆深埋还田时，还田刀作业功耗过高和缠草的问题，结合还田机作业过程，分析还田刀功耗过高和缠草的原因，设计了一种反旋深埋滑切还田刀。使用阿基米德螺旋线设计还田刀侧切刃，提高还田刀的滑切性能，计算并验证侧切刃曲线的动态滑切角满足土壤-秸秆滑出还田刀的条件，使用圆弧曲线设计还田刀正切面，以耕宽和正切面安装角为依据确定圆弧半径为60mm。运用离散元仿真软件EDEM进行了反旋深埋滑切还田刀与传统还田刀的仿真对照试验，结果表明反旋深埋滑切还田刀的秸秆还田率、抛土性能与传统还田刀基本一致，作业功耗降低18.19%，选取留茬高度、刀辊转速和机具前进速度为影响因素，选取作业功耗为评价指标进行正交试验设计，确定影响还田机作业功耗的因素从大到小依次为：刀辊转速、机具前进速度、留茬高度。田间试验结果表明：在土壤含水率为20%~30%，地表秸秆覆盖量为336~353g/m2，拖拉机作业速度为低速一挡（1.5km/h），刀辊转速为250r/min时，秸秆深埋滑切还田刀作业后，平均耕深为18cm左右，秸秆还田率为87.9%~89.7%，地表平整度为2.1~3.7cm，作业指标均满足秸秆还田的农艺要求。

Optimal Design and Experiment of Deep-buried Reverse Rotating Sliding Cutting Straw Returning Blade

Aiming at the problems of high power consumption and straw entanglement of rice straw returning to the field, combined with the operation process of the straw returning machine, the reasons of high power consumption and straw entanglement of the straw returning blade before optimization were analyzed, and a kind of reverse rotating deep-buried sliding cutting returning blade was designed. The Archimedes spiral was used to design the side cutting edge of the straw returning blade to improve the sliding cutting performance of the straw returning blade and the dynamic sliding cutting angle of the side cutting edge curve was calculated and verified to meet the condition that the soil and straw slipped out of the straw returning blade. The arc curve was used to design the tangent section of the straw returning blade and the radius of circular arc was determined to be 60mm on the basis of ploughing width and installation angle of tangent section. The EDEM simulation software was used to simulate and compare the straw returning blade with the straw returning blade before optimization. The results showed that the straw returning rate and throwing performance of the reverse rotating sliding cutting returning cutter were basically the same as those of the optimized previous straw returning blade, and the working power consumption was reduced by 18.19%. The stubble height, cutter roll speed and machine forward speed were selected as three factors, and the working power consumption was selected as the evaluation index to carry out the orthogonal test design. Finally, the factors affecting the working power consumption of the straw returning blade from big to small were determined as follows: cutter roll speed, machine forward speed and stubble height. The field test results showed that when the field soil moisture content was 20%~30%, the surface straw coverage rate was 336~353g/m2, the tractor operating speed was 1.5km/h, and the blade roller rotating speed was 250r/min, the operation effect of straw deep-buried sliding cutting returning blade was that the average tillage depth was about 18cm, the returning rate was 87.9%~89.7%, and the surface flatness was 2.1~3.7cm. All the operation indexes met the agronomic requirements of straw returning, and the rationality of simulation test was verified.