Design and experiment of cleaning and covering mechanism for no-till seeder in wheat stubble fields

摘要

A new type of cleaning and covering mechanism,used for no-till seeder in wheat stubble fields,has been designed to solve the problem of straw blocking of seeders and shortage of anti-blocking mechanisms in wheat residue covered fields in annual double cropping area of China.Spring tine was selected as the key part for cleaning,and transverse moving of straw and driving anti-blocking were chosen in this mechanism.Its parameters optimization was studied with the method of L9(34) orthogonal test in order to find out a reasonable form.The optimal combination of influencing factors was obtained by the experiment:linear velocity of spring tines was 20.72 m/s,operation speed was 4.5km/h,arrangement of spring tines was seven rows and angle of baffle was 75°,meanwhile,the cleaning ratio was more than 98％,the covering evenness and width were 7.48 and 2.89 m respectively.The field experiment of seeding performance of no-till seeder on which the mechanism fixed was conducted according to "Testing Methods of Single Seed Drills",and the result showed that the qualified rate of spacing,the miss rate,the multiples rate and the coefficient of variation of qualified spacing satisfied the requirement of superior class,the sowing depth rate attained the requirement of fust class,under the condition that the theory spacing were 6 and 8 cm,and the theory sowing depthwas 3～5 cm.Above all,the cleaning and covering mechanism has important value in solving the problem of no-till mechanization seeding in wheat stubble field.%针对黄淮海一年两熟地区麦茬地免耕播种存在秸秆堵塞单体,缺少适宜的防堵装置等问题,研制了一种用于麦茬地免耕播种机的清秸覆秸装置,该装置采用弹齿作为清秸部件,并融合了秸秆横向位移的思想和主动式防堵的特点.为确定清秸覆秸装置的合理结构,采用L9(34)正交试验方法,对该装置的参数进行了优化试验.结果表明:弹齿线速度20.72 m/s、作业速度4.5 km/h、弹齿齿数7排、挡板角度75°时,清秸率达98％以上、覆秸均匀度达7.48、覆秸宽度达2.89 m.按照国家标准GB/T6973-2005《单粒(精密)播种机试验方法(Testing Methods of Single Seed Drills)》对免耕播种机进行了田间播种性能试验.结果表明,在理论株距分别为6和8 cm,理论播深为3～5cm条件下,免耕播种机的粒距合格指数、重播指数、漏播指数及株距变异系数均达到了国家部颁标准优等品要求水平,播深合格率达到一等品的要求水平.该研究对解决麦茬地免耕杌械化播种问题具有参考意义.