定甩刀防缠式香蕉秸秆粉碎还田机设计与试验

针对香蕉秸秆粉碎机具缠绕造成秸秆粉碎率不达标等问题,该研究设计了一种定甩刀防缠式香蕉秸秆粉碎还田机。在粉碎过程中,粉碎定刀与高速运转中的Y型甩刀对香蕉秸秆形成三点支撑,进而实现秸秆粉碎与避免秸秆缠绕。其中,Y型甩刀由2个L型刀片组合的Y型粉碎刀与甩刀构成。确定了各关键部件的结构参数、动定刀排列组合方式及香蕉秸秆粉碎过程受力分析,明确了影响粉碎效果的主要因素为机具前进速度、粉碎刀辊转速以及Y型甩刀折弯角。以前进速度、刀辊转速和甩刀折弯角为试验因素,以香蕉秸秆粉碎合格率和抛撒不均匀度为评价指标,进行三水平三因素正交田间试验,确定优化参数组合为前进速度1.85 m/s,刀辊转速1 500 r/min,Y型甩刀片折弯角140°,此时香蕉秸秆粉碎合格率为95.1%,抛撒不均匀度为14.6%,满足香蕉秸秆粉碎作业性能要求。与已有秸秆粉碎机进行性能对比试验,结果表明,该研究研制的定甩刀防缠式香蕉秸秆粉碎还田机秸秆粉碎合格率提高了1.7个百分点,防缠性能更优。该机具的研制对解决蕉区秸秆粉碎还田关键技术问题具有重要意义和应用价值。

Design and experiment of banana straw crushing and returning machine with anti-wrapping device supported by flailing blade

Abstract: Banana straw is usually broken into pieces to degrade naturally in the farmland. However, severe entanglement of knife roller easily causes the wear of blades, leading to a short service life and low crushing efficiency in the conventional banana straw-crushing and returning machine. A great challenge has also been posed on the effective coordination of fixed knives during operation, especially in the case of high toughness after the aging of banana straw. Therefore, this study aims to improve the smashing rate of banana straw up to the standard requirement, thereby avoiding the winding of banana straw in pulverizers. An anti-wrapping device with a fixed flailing knife was also designed to reduce the entanglement for the banana straw-crushing and returning machine. Specifically, the movable and fixed knife was effectively coordinated in the machine. Three-point support was also formed using the crushing fixed knife and the Y-shaped flailing knife in high-speed crushing operation for the banana straw. As such, the highly efficient straw-crushing was realized to avoid straw entanglement. Among them, the Y-shaped flailing knife was composed of two L-shaped blades combined with a Y-shaped flailing knife and a flail. A systematic investigation was made on the optimization of structural parameters for the key components of crushing, the arrangement and combination of fixed knives, as well as the force analysis of banana straw during crushing. Correspondingly, the main test factors were determined as the forward speed of the returning machine, the speed of the crushing knife roller, and the bending angle of the Y-shaped flailing knife. A three-level three-factor orthogonal field test was then carried out, where the evaluation indicators were set as the crushing qualification rate of banana straw, and the unevenness of throwing. An optimal parameter combination was achieved, where the forward speed was 1.85 m/s, the knife roller speed was 1500 r/min, and the bending angle of the Y-shaped flailing knife was 140°. In this case, the crushing qualification rate of banana straw was 95.1%, and the unevenness of throwing was 14.6%, indicating suitable for the actual situation of banana straw crushing. A comparison test was also conducted to verify the performance of the improved pulverizer. It was found that the qualified rate of straw smashing increased by 1.7 percentage points in the fixed-blade anti-wrapping banana straw crushing and returning machine, where the anti-wrapping device performed better. Consequently, the anti-wrapped banana straw crushing and returning machine with a fixed flailing knife can be expected to realize the sliding cooperation of the flailing and fixed knife for a better crushing effect, thereby reducing the entanglement of crushing knife roller. As such, the higher squeezing force of the cutter on the straw greatly contributed to effectively improving the crushing performance under the optimal operation requirements in the southern banana areas. The finding can provide strong technical support to the straw crushing and returning to the field in the banana areas.