Modellering och design av elmotor för mutterdragare
This thesis was carried out at Atlas Copco Tools and Assembly Systems. The purpose hasbeen to develop a design tool to be used for development of new electric motors for AtlasCopcos electric nutrunners. The focus of the thesis has been to increase productivity bydecreasing the power losses in an electric tool. The productivity is defined as themaximum number of tightenings a nutrunner can perform without becoming too hot.Before starting the development of this design tool an existing Matlab script, whichcalculates the losses in a slotless electric motor, has been studied and modified torepresent the real losses in a better way. The modification has been made by performingpractical studies of different losses and then adjusting existing parameters in the Matlabscript.Because design changes in one part of a mechatronic system can lead to a decrease inperformance of another part the choice of parameters that can be changed has been madeso that other parts of the system is affected as little as possible.A study of the existing tools efficiency during an entire tightening has been made toincrease the understanding of when and where the different losses appear and to comparethe modified Matlab script with the measured values.The design tool was formed so that it executes the Matlab script, that calculates thelosses, for a number of different design options and stores the alternative which producesthe least losses. The result of this parameter study together with the study of the toolsefficiency enables a number of conclusions to be drawn about what needs to be changedin the existing tool to decrease the losses.