草地破土切根刀具的刃口曲线设计与优化
Design and optimization of the edge curve of root-cutting blade in grassland

为降低退化草地切根改良机械的作业功耗,根据草地切根作业的要求,按照滑切角的变化规律,设计了基于对数螺线、阿基米德螺线、正弦指数曲线、偏心圆弧线的4类16种刀具刃口曲线。通过土槽试验,测得不同种类刃口曲线刀具与土壤作用的牵引力和扭矩,计算得到比功耗大小;拟合不同种类曲线的参数与比功耗的关系,以比功耗最小为目标,优化得到不同种类曲线的最优参数组合,再比较4类刃口曲线最优参数组合下的最小比功耗大小,得到最优的刀具刃口曲线。优化结果表明,初始静态滑切角为40°,静态滑切角的增量与极角的比例系数为-0.1时对应的正弦指数曲线切根比功耗最小,为3 345 kJ/m3,是试验条件下的切根最优刃口曲线。
To decrease the electricity power used in rut root-cutting, 16 blades of four different types of edge curves (logarithmic spiral, Archimedes spiral, exponential sine curve and eccentric circular arc line) were designed according to the requirement of grassland root-cutting and the change regularity of the sliding cutting angle.Through soil-bin experiment, the pull force and rotation torque of the designed blades were measured, power consumptions were calculated.The relationship between and parameters of the four types of the edge curves was simulated, and the best combination of the parameters of each edge curve was obtained for the smallest power consumption.By comparing the power consumption of different edge curve under the best combination of all parameters, the most suitable edge curve was identified.The result of the experiment optimization indicated that the lowest power consumption reached 3 345 kJ/m3 when the edge curve was exponential sine curve which its beginning static sliding cut angle was 40° and the proportional coefficient between the increment of the static sliding cutting angle and the polar angle was -0.1.