Jixie qiangdu (Jan 2018)
RESEARCHON CHARACTERISTICSOFACTUAL HINGEJOINT LOAD OF HYDRAULIC EXCAVATOR WORKING DEVICE
Abstract
In order to quantitatively analyze characteristics of the hinge joint loads under actual working conditions,and provide basis for compiling the load spectrum of key components,a medium-sized excavator XE215 G was taken as the research object,whose hinge joint loads was obtained by two methods. The first is using the three-dimensional pin-shaft force sensor to measure the positive load,lateral load and offset load at the hinge joint of stick and bucket,and using the link rod force sensor to measure the link rod force,and then the other hinge joint loads could be calculated by the mechanical equilibrium equation; The second is using the measured pressure and displacement of the boom cylinder,stick cylinder and bucket cylinder to calculate all hinge loads indirectly by a kinetic model. Simultaneously,the stress-time histories of the large stress measure points on the boom and the stick were recorded. The hinge joint loads obtained by the two methods were in good agreement with each other,indicating that the test is reliable. For method 1,the relative deviations of fatigue damage of each measure point between including and excluding lateral load and offset load is less than 6. 98%,except for a measure point whose fatigue damage is obviously smaller than other points,which indicates that the lateral load and the offset load have little effect on fatigue damage. For method 2,the calculated stress of each measure point obtained by the load-stress transfer coefficient was compared with the measured stress of the corresponding point. The results show that they are in good agreement with each other and the most relative deviation between the calculated damage and the actual damage is 8. 33%,which indicates that the hinge load obtained from the method 2 can reproduce the stress and damage of each measuring point well. Under normal working conditions,the hinge joint load of theexcavator working device can ignore the lateral load and offset load approximately,while can be obtained by the simple and feasible method of measuring the cylinder pressures and displacements.
