水稻秸秆激荡滑切与撕裂两级切割粉碎装置设计与试验

Design and Experiment of Rice Straw Chopping Device for Agitation Sliding Cutting and Tearing

针对东北稻区秸秆还田作业中存在的粉碎效果差、秸秆腐解速率慢的问题,提出了适合该区域秸秆翻埋还田秸秆粉碎状态,为5~10 cm撕裂状态。结合预达到粉碎后秸秆形态及现有机具使用情况,设计了具有激荡滑切和撕裂两个阶段并与联合收获机装配的秸秆粉碎装置,通过理论分析对粉碎过程关键参数进行了设计。单因素试验表明:秸秆含水率从69.77%减少到29.34%时,秸秆因受干物质含量和弯曲强度改变影响,秸秆粉碎长度合格率和破碎率分别下降6.44、9.55个百分点,抛撒幅宽有先增加后减少趋势;秸秆粉碎长度合格率和破碎率随收获速度增加有较大幅度降低,抛撒幅宽减少0.22 m;粉碎刀轴转速从2100 r/min提高至2850 r/min时,秸秆粉碎长度合格率和破碎率都有显著提高,抛撒幅宽也有较大幅度增加;两级定刀直线间隔变大,秸秆粉碎长度合格率和破碎率有小幅度增加,抛撒幅宽减小0.11 m。正交试验表明:秸秆粉碎长度合格率和破碎率受收获速度和粉碎刀轴转速影响规律基本一致,收获速度和粉碎刀轴转速对秸秆粉碎长度合格率和破碎率影响更显著(P<0.05);粉碎刀轴转速和两级定刀直线间隔对抛撒幅宽影响较显著(P<0.05)。设计的装置对东北稻区秸秆还田关键技术问题具有重要意义和应用价值。

In the rice planting area of Northeast China,the large amount of rice straw with low moisture content is tough to chop during harvest,and straw decomposed slowly under low accumulated temperature.However,the existing machines and tools still cannot better achieve straw return to the field.The suitable chopping state of straw returned to the field was proposed,which was 5~10 cm tearing state.Combined with the shape of the chopped straw and the use of the existing machines and tools,a straw chopping device with two stages of agitation,sliding cutting and tearing was designed and assembled with the combine harvester.The key parameters of crushing process were designed by theoretical analysis.The single factor test showed that when the moisture content of straw was decreased from 69.77%to 29.34%,the chopping qualified rate and broken rate of straw were decreased by 6.44 pencentage points and 9.55 pencentage points respectively due to the change of dry matter content and bending strength,and the spread width was increased first and then decreased.With the increase of harvest speed,the chopping qualified rate and broken rate of straw was decreased significantly,and the width of straw was reduced by 0.22 m.With the increase of shaft speed from 2100 r/min to 2850 r/min,the chopping qualified rate and broken rate of straw were significantly increased,and the width of straw was also greatly increased.The interval of the two-stage fixed knife was enlarged,the chopping qualified rate and broken rate of straw were increased slightly,and the change range of the scattering width was less than 0.11 m.Orthogonal test showed that the effect law on chopping qualified rate and broken rate of straw caused by harvesting speed and the rotational speed was almost consistent.The chopping qualified rate and broken rate of straw caused by harvest speed and cutter shaft speed were more significant(P<0.05).The spread width caused by cutter shaft speed and the interval of the two-stage fixed were more significant(P<0.05).The design of the device was of great significance and application value to the key technical problems of straw returning in the rice planting area of Northeast China.