Research And Optimization Of Double-Jaw Crusher On Kinematics And Dynamics

In this paper,a new double-jaw crusher was proposed and researched.The double-jaw crusher was simplified as six-bar seven-pair kinematic chain and the closed vector approach was applied to build the kinematic model of double-jaw crusher.The trajectory equations of some special points on upper and lower jaw were established and the velocity and acceleration characteristics of these points varied with rotation angle were studied by using MATLAB.Then the stroke value of upper and lower jaw,the travel velocity-ratio coefficient and the range of the transmission angle were calculated.The research shows that the trajectory,velocity and acceleration of special points are reasonable and meet the application requirements;The suitable stroke value could guarantee the shape and the granularity of products;The travel velocity-ratio coefficient approaches “1”,which means the crusher run smoothly;The range of the transmission angle is suitable,which guarantees the high mechanical efficiency of the crusher.The dynamics model of the double-jaw crusher was built through analyzing the forces applied on the components and establishing the balance equations of the components.According to the dynamic model,the curves that indicate the variation law of the forces applied on each component were got by applying the suitable load,which laid the foundation for the vibration force optimization of key components.The virtual prototype was set up according to the simplified mechanism of six-bar seven-pair kinematics chain and the simulation was carried out after setting some suitable parameters.The results shows that the simulation tested the mathematical model,which matches the analysis of the model.Compared with the jaw crusher whose structure parameter equal to the double-jaw crusher,the result shows that the stroke feature value and the minimum transmission of double-jaw crusher is larger than jaw crusher,the travel velocity-ratio coefficient is closer to “1”,and the driving torque is smaller by 59%,under the same load.Therefore,the double-jaw crusher is equipped with much more obvious advantages than jaw crusher.Using the optimization toolbox of MATLAB,the optimum vibration balance method was used to optimize the vibration force of the double-jaw crusher.The optimization result shows that the double-jaw crusher operates best,when the balance mass is 533 kg,the angle between crank and the line from balance mass center to rotary center is 295° and the distance from balance center to rotary center is 0.5m.After optimization,the maximum vibration force was reduced by 50% and the maximum amplitude of the vibration force was reduced by 72%,which improved the stability and reliability of crusher and prolonged the service life of the double-jaw crusher.The kinematic and dynamic modeling,analysis and optimization of the new double-jaw crusher had a great theoretical and practical significance for providing an effective method for innovation and optimization of the similar mechanisms.