免耕播种机有支撑滚切式防堵装置设计与试验

针对玉米秸秆覆盖、留茬地免耕播种时存在根茬和玉米秸秆不易破除等问题,设计一种同时设有被动卧式旋转部件和主动卧式旋转部件的有支撑滚切式防堵装置,通过试验和理论分析的方法分别设计被动切割刀片和主动切割刀片,其中被动切割刀片的刀刃曲线采用等滑切角曲线,主动切割刀片的刀刃曲线采用阿基米德螺线。为确定刀刃曲线最佳参数进行土槽试验,分别对主动卧式旋转刀具和被动卧式旋转刀具进行二次旋转组合试验,运用Design-Expert软件建立各因素与各指标之间的回归方程,得出最佳参数组合为:主动卧式旋转刀具转动速度为120 r/min、主动切割刀片回转半径为240 mm;被动切割刀片回转半径为185 mm,被动切割刀片作业深度为95 mm;并此状态下进行田间验证试验,得出玉米秸秆根茬切断率平均值为91.3%,单把主动刀片功率消耗平均值为145.2 W,该研究可为玉米留茬覆盖地免耕播种机整机设计提供参考。

Design and experiment of supported roll-cutting anti-blocking mechanism with for no-till planter

Abstract: A supported roll cutting type anti-blocking mechanism for no-till planters was designed to cut corn residues (stalks and stubble) during operation of the no-till planter in the stubble mulch field. The mechanism is equipped with both active and passive horizontal rotating parts, which can cut residues more effectively. The active horizontal rotating parts are used for cutting residues; the passive ones are used for supporting the residues left on the surface, making them always lie between the active horizontal rotating and passive horizontal rotating parts, thus preventing them from being thrown out by the cutting blade during cutting operations. The anti-blocking mechanism cuts the residues in a supported way, just like a pair of scissors, reducing power consumption during operation. The anti-blocking mechanism, which works in a passive way, is placed in front of the opener and has a combined blades structure. Eight slide-cutting blades are fixed on a blade disc and the adjacent blades are mounted on each side of the disc respectively. When it works, the blade disc travels along with the tractor and rotates about the blade shaft under the action of the soil resistance. The side-cutting blade only cuts off the stalk in a slide cutting way without crushing, thus both the rotational speed and power consumption of the blade can be reduced. Stalks can be cut off effectively when the tillage depth is not more than 60 mm through an optimal design of the curve of the side cutting edge of the slide-cutting blade. Field tests were conducted to determine the optimal operational parameters, and the rotary quadratic combination design was carried out for the active rotating blade and passive rotating blade respectively. The regression equations showing the relationship between both factors and indexes were obtained by using the Design-Expert software. Straw cutting rate increased with the increase of the radius of the passive cutting blade, and the trend of rising and gradually slowing down; Single passive cutting blade power consumption increased with the increase of the radius of the passive cutting blade, and the trend of rising gradually increases; Straw cutting rate increased with the increase of the working depth, and the trend of rising and gradually slowing down; Single passive cutting blade power consumption increased with the increase of the working depth, and the trend of the rising was gradually enhanced. Straw and stubble root cutting rate increased with the increase of the radius of the active cutting blade, and the trend of rising and gradually slowing down; Single active cutting blade power consumption increased with the increase of the radius of the active cutting blade, and the trend of rising gradually increases; Straw and stubble root cutting rate increased with the increase of the active horizontal cutter blade rotation speed, and the trend of rising and gradually slowing down; Single active cutting blade power consumption increased with the increase of the active horizontal cutter blade rotation speed, and the trend of rising gradually enhanced.The results showed the best parameter combination: the rotation speed of 120 r/min and a turning radius of 240 mm for the active rotating blade; the turning radius of 185 mm and a working depth of 95 mm for the passive rotating blade. Verification tests indicated that the corn stalk and stubble cut-off rate was 91.3% and the power consumption of a single blade was 145.2 W. This study can provide a reference for the design of no-till planters.