Research Of Rock Breaking Mechanism For Hydraulic Breaking Hammer

The research of rock breaking mechanism is lagging behind the application ofhydraulic breaking hammer. There is significant limitation between the performanceof the hydraulic breaking hammer’s application. Based on the drilling theory of rock,the experiment results, the production experience and the production data, this paperfocus on the application and rock breaking mechanism of hydraulic breaking hammer.This paper analyzed and compared the models of output stress wave. Based onthe model of elastic rod impact on elastic rod, a formula of the hammer’s output stresswave was established. According to the output stress wave and the process of chiseltool intrude into rock, the formula of chisel tool’s penetration load was presentedwhich is the foundation of further study in this area.Based on the analysis of the breaking rock model for hydraulic breaking hammer,the model of point load and the formula of chisel tool’s penetration load was appliedto establish the formula of critical impact energy for breaking boulder. Comparedwith the results obtained in the mines, it turned out that the result of the formula withthe actual critical impact energy are same. As the analyze result of the relationshipbetween the large rock property and the critical impact energy, although themaximum penetration load is declining with the strength of the rock, the crushingvolume is still rising.One of the most common application for hydraulic breaking hammer in mine issplit breaking rock. According to the model of Evans, this paper established theformula of single split maximum thickness of rock. Compared with the resultobtained from varies manufacture, it showed that when the split thickness of rock is0.3m, the single impact energy must be more than10000J. Another discover from theanalyze result of the relationship between the chisel tool angle and the split thicknesswas that a smaller chisel tool angle is great for split breaking rock.3kinds of characteristic parameters was analyzed by the author which are thesingle impact energy, the working weight and the chisel tool diameter. The result wasthat the single impact energy was the most reasonable characteristic parameters. Inorder to analyze the relationship between the3kinds of characteristic parameters,289 kinds of characteristic parameters was collected from23manufacturers of hydraulicbreaking hammer. The mathematical statistics and linear regression method wereapplied by the author aiming to analyze the relationship between the characteristicparameters. It indicated that the impact energy of the hammer per working mass wasabout2.9J/kg, and the ratio of single impact energy to the square of drill rod diameterwas about0.41J/mm2.Based on the statistics result of the relationship between the working weight withthe carrier weight and the actual energy efficiency of hammer, it indicated that thecarrier weight is9~15times of the weight hammer. The actual energy efficiency ofhammer is50%~70%and the average was58%.