LABORATORY STUDY RESULTS OF SOIL-CUTTING OPERATING ELEMENTS

Studying the wear of soil-cutting working tools in the field conditions has certain difficulties associated with the impermanence of soil properties. The paper presents the results of a laboratory study of the power characteristics in the process of wearing of a soil-cutting wedge in an artificial abrasive soil medium. (Research purpose) To determine the nature of changes in cutting forces in vertical and horizontal planes depending on the conditions and a degree of wear of a soil-cutting wedge. (Materials and methods) For the experiment, use was made of quartz as an abrasive material, paraffin with additives of ceresin and petrolatum as binding components; cement was additionally introduced to change the granulometric composition of a soil model, and a cross-planer was used as a drive mechanism. (Results and discussion) It has been shown that the horizontal component, or traction resistance, increases linearly with increasing the depth of cutting. An increase in the soil-cutting velocity also leads to an increase in the traction resistance of the wedge, and its magnitude increases in a power-law dependence on the velocity. It has been established that the cutting angle affects not only the variation of the wedge traction resistance, but also the shearing pattern, which changes as it increases and changes from shear shavings into shift shavings, which contributes to the traction force growth. It has been found that an increase in traction resistance is affected by an increase in the hardness of abrasive material and a decrease in the distribution density of solid particles in its volume. As the width of the back chamfer and the angle of its inclination to the furrow bottom increased, the traction characteristics both in the vertical and horizontal planes increased as well, the back chamfer width having the greatest influence on the vertical component. As the blade worn out depending on the friction path, the vertical component of frictional forces increased sharply, while the horizontal component increased insignificantly. (Conclusions) The results of the conducted studies have shown that the wedge depth mainly depends on the back chamfer width. The traction resistance of the wedge is greatly influenced by physical and mechanical properties of an abrasive medium, cutting conditions and a degree of the blade blunting.