Analysis And Experimental Study On Dynamic Balancing Performance Of Crankshaft Connecting Rod Assembly Of Single Cylinder Engine

The dynamic unbalance of crankshaft connecting rod assembly is a primary factor leading to engine’s vibration.To weaken vibration of engine and improve comfort of driving, it’s necessary to ensure the excellent dynamic balance performance of crankshaft connecting rod assembly.Axis-angle and unbalance percentage are key parameters measuring dynamic balance performance.They always fluctuates in a certain range in actual production,and dynamic balance performance is unstable.Strengthening stability of axis-angle and unbalance efficiency is very important in production.The project conducted following research and made some achievements.Studied manufacturing process of crankshaft connecting rod assembly through theoretical analysis and experiment,and figured out that manufacturing accuracy of crank’s hole jointsing with crank pin has great influence on deviation of coaxiality of axes of left crank shaft and right crank shaft,and then influences axis-angle and unbalance efficiency.According to structure of crank shaft,analyzed calculation method of axis-angle,unbalance percentage,maximal first-order inertial force and minimal first-order inertial force,and offered corresponding mathematical expressions.Based on that,built 3D model of crank shaft and calculated position of centroid.Referring to mathematical expressions,programmed and calculated values of dynamic balance parameters in MATLAB.On that bases, programmed and drew graphs of axis-angle and unbalance efficiency to ratio of all resultant rotating mass to all resultant reciprocating mass and angle of off-center rotating mass.Drilled at 3D model of crank shaft in Pro/E,calculated values of axis-angle and unbalance percentage,figured out strategy of decreasing mass of crankshaft connecting rod assembly referring to graphs of axis-angle and unbalance percentage to ratio of all resultant rotating mass to all resultant reciprocating mass and angle of off-center rotating mass.Analyzed and studied the influence of alteration of structure of crank shaft on axis-angle and unbalance percentage.This project provided reference for design and development of new product-crankshaft connecting rod assembly,and technical instruction for adjustment of dynamic balance performance parameters in actual manufacturing,and saved resources of human,material and finance for enterprise.