Precision Analysis And Tolerance Optimization Design Of Slider-crank Mechanism Considering Contact Random Of Clearance In Revolute Joint

Kinematic accuracy of slider crank mechanism is directly influence on machine’sperformance, for example, the quality of stamping products is directly ensured by theslider position precision at the bottom dead center of the mechanical press. However,Kinematic accuracy of slider crank mechanism is also effected by contact random atthe joints; For this reason, it is important significant that precision analysis for slidercrank mechanism and tolerance optimization design for revolute joint. Slider crankmechanism is regarded as the research object in this paper, the revolute joint betweenthe slider and the connecting rod., as well as between the connecting rod. and sliderare considered..Firstly, contact random at the revolute joint distribution model isdeveloped, the influence of contact random on kinematic accuracy of slider isanalyzed..to the key dimensions of slider crank mechanism, tolerance optimizationdesign model is established. The main research work is as follows:1.Combined mechanism dynamics method with probability and statistics theory, thejudgment criterion for contact position at revolute joint is proposed, dynamicsimulation for slider crank mechanism having two revolute joints with clearance inthe ADAMS software is analyzed, the effects of clearance sizes and rod length areinvestigated in respect to random model of contact at revolute.2.Based on the continuous contact model, the slider motion equations is establishedby using the mechanism vector analysis method, the errors transfer model betweenclearance angle and the slider displacement is developed, the effect of variousclearance size on slider displacement error probability distribution is analyzed, andthe influence situation of different revolute joint on mechanism performance isthoroughly investigated.3.Experimental system for slider displacement acquisition is constructed, whichconsists of a slider crank mechanism with an adjustable radial clearance at therevolute joint, linear transducer and data acquisition tool. The probability distributionof slider displacement errors is analyzed under the crank angle equal to2π and π fordifferent clearance sizes, the correlation between the numerical and experimentalresults is discussed.4.The influence which is the contact randomness of revolute joints on the sliderposition accuracy is included, under the condition of guarantee mechanism motion output precision, the quality loss and manufacturing cost minimization ofcomprehensive product are regarded as the objective function, the toleranceoptimization model of the shaft hole diameter size at the Slider crank mechanismrevolute joints is established, and the optimization model is solved by the use oflstopt optimization analysis software.