Effect of contact characteristics on the self-rotation performance of conical picks based on impact dynamics modelling

Abstract

Conical picks have a harsh working environment and 70% of their failures are caused by wear. It has been found that conical picks can rotate while interacting with the working material. This self-rotation ability is an important factor affecting pick wear, but the self-rotation mechanism remains unclear. Researching the mechanism involves the impact and friction dynamics of the interaction between a pick and its holder. Thus, a dynamic finite-element numerical model for the pick–holder interaction is established. How the handle–holder gap width, pick body and handle lengths and pick handle diameter affect the settling time and the percentage of time with no contact is studied to compare the numerical results with the equivalent effects on the rotation angle in experiments. Doing so indicates that the main factor in the self-rotation ability of a conical pick is not the magnitude of the contact load but its duration. The present research provides a new method for revealing the mechanism for the self-rotation of conical picks.

Study of the Regularities of Non-Uniformity of Loads Formation on the Cutters of the Executive Body of the Coal-Mining Combine Harvester

“…A schematic diagram for determining the variation coefficient of chip thickness at the actuator picks: γ 1охв , γ 2охв -angles of the actuator reach at the chip thicknesses of h 1 and h 2 ет вариацию толщины стружки на резцах исполнительного органа, которую принято оценивать коэффициентом вари ации ν h i . Его величина оценивается исходя из следующих соображений [3,12,13]. Для произвольно выбранных для резца исполнительного органа положений 1 и 2 с соответ ствующими координатами и при данной средней скорости подачи, определяющей среднюю максимальную толщину стружки h max , средняя толщина стружки h i равна:…”

Improving the operational durability of tangential-rotary picks for rock cutting with central spraying and hydrodynamic rotation

“…These studies use modern research techniques, including the finite element method (FEM) and the discrete element method (DEM), as well as measurements at laboratory stations and in operational conditions. Theoretical and experimental research mainly concerns: the mechanics of rock cutting with conical picks 5 , the prediction of the load on conical picks and the energy consumption of mining, especially hard rocks 6 – 9 , the formation of stresses in the pick tip and its shaft 10 – 12 , the interaction of the pick with the pick holder 13 , the distribution of stresses in the pick holder with a pick placed within it 14 , and the wear mechanisms of the picks in the rock mining process 15 . …”

Research on Cutting Characteristics of Rock Plate with Two Sides Fixed and Two Sides Free

“…Su and Akkaş [23] researched the wear mechanism of two different types of conical picks and pointed out that metallurgical composition, pick position, and other environmental conditions had influence on wear mechanism. Liu [24] and Geng researched the influence of self-rotation on rock wear. Zhou et al [25] combined theory and experiment to study dust generation in the process of rock breaking by pick, showing that the tip angle and attack angle had important influence on the dust generation.…”