准线形式对土壤工作部件触土曲面几何形式、工作阻力和土壤扰动状况均有重要影响。从曲率趋势线、曲率半径梳和曲率半径中心轨迹3个角度,分析了直线、圆弧线、摆线、抛物线及仿生曲线等5种典型触土曲面准线形式的内在几何特征及其与减阻性能之间的关系。准线形式或触土曲面形式的改变直接改变了与之接触的土壤所受法向压力作用规律,并通过改变切土阻力、土壤内摩擦阻力、土壤-触土曲面摩擦阻力及对底部土壤的压实阻力等因素中的一种或几种,使得整体工作阻力和土壤扰动产生了不同效果。研究结果表明:具有较简单常数曲率变化趋势的直纹面、圆弧面减阻性能相对较差;曲率半径中心轨迹具有多个极值点、有拐点且分段连续特殊几何特征的仿生曲面,在工作过程中能够同时降低土壤内摩擦阻力、土壤-触土曲面摩擦阻力及对底部土壤的压实阻力等几个因素的水平,并可获得极佳的减阻性能。研究对于深入掌握触土曲面几何与力学特性及触土曲面高效节能设计方法具有较重要的参考意义。
The soil- engaging surface directrix form of soil working components has great influence on the geometric shape, working resistance and soil disturbance state. The internal geometric characteristics and their resistance reduction performance of five kinds of classic soil-engaging surface directrix including straight line, circular arc, cycloid curve, parabola and bionic curve were analyzed from the point of view of curvature trendline, curvature radius comb and trace line of curvature center. The change of directrix form or soil-engaging surface shape directly changes the normal pressure regulation of soil in contact with it. It ulteriorly changes one or several factors among the cutting resistance, soil internal friction resistance, friction resistance between soil and soil-engaging surface, and soil compaction resistance beneath the cutting tool. Thus, the different effect of the total working resistance and soil disturbance state is produced. The straight and arc directrix surface have relatively poor resistance reduction performance for their simple curvature trend line. However, the bionic directrix surface, whose trace line of curvature center has the special geometric characteristics of multi-extreme points, inflection point and sectionally continuous, possesses extremely resistance reduction performance for it can simultaneously reduce the value of soil internal friction resistance, friction resistance between soil and soil-en- gaging surface, and soil compaction resistance. The research for deeply grasping the geometric and dynamic characteris- tics and high-efficient and energy-saving design method of soil-engaging surface has important reference significance.