Modeling And Optimization Of Worm And Worm Tolerance Based On SDT

The worm is a kind of transmission mechanism is widely used in modern machines,it has a single large transmission ratio,smooth transmission,low noise and self locking characteristics,and precision worm gear as precision indexing precision or motion mechanism,can be used in gear cutting machine,machining center,precision indexing turntable and instrument etc.as the occasion,the king of precision mechanical grating machine,worm indexing system is one of the most important parts,the accuracy of grating ruling engine plays an important role,so the worm precision grating design machine is very important.Point movement based on the theory of homogeneous matrix motion in space is derived,the rigid body assumption and small changes in assumptions based on the SDT theory,SDT matrix obtained 6 screw parameter,and gives the steps of tolerance modeling SDT based on the theory;for center distance deviation,axis angle deviation,middle plane deviation,the SDT matrix is given and established the changes in inequality and inequality constraint model.The worm tolerance modeling problem,analyzes the classification method based on domain tolerance tolerance,tolerance mathematical modeling theory based on SDT is presented,with variable equations and constraint equations based on SDT tolerance modeling,worm tolerance mathematical model is established including center distance deviation,axis angle deviation and deviation of the middle plane.Based on this model,the design variables of SDT screw parameter change is defined as the model,then the distribution of these design variables corresponding to the quantity change,using the Monte Carlo method for sampling to simulate the actual processing,generating change instance parameters to achieve tolerance analysis,the mathematical model of SDT system based on the statistical test method.The traditional cost tolerance model,based on the SDT model,constructed by the deviation parameter as a variable,the minimum processing cost worm tolerance optimization model for the optimization objectives,according to the model,using the genetic algorithm,the deviation from the center axis angle deviation,middle plane deviation was optimized,the deviation of optimal solution.Finally through the deviation of domain to domain mapping for tolerance,tolerance optimal solution.