Modellering och design av elmotor för mutterdragare

Sammanfattning

This thesis was carried out at Atlas Copco Tools and Assembly Systems. The purpose has

been to develop a design tool to be used for development of new electric motors for Atlas

Copcos electric nutrunners. The focus of the thesis has been to increase productivity by

decreasing the power losses in an electric tool. The productivity is defined as the

maximum number of tightenings a nutrunner can perform without becoming too hot.

Before starting the development of this design tool an existing Matlab script, which

calculates the losses in a slotless electric motor, has been studied and modified to

represent the real losses in a better way. The modification has been made by performing

practical studies of different losses and then adjusting existing parameters in the Matlab

script.

Because design changes in one part of a mechatronic system can lead to a decrease in

performance of another part the choice of parameters that can be changed has been made

so 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 to

increase the understanding of when and where the different losses appear and to compare

the modified Matlab script with the measured values.

The design tool was formed so that it executes the Matlab script, that calculates the

losses, for a number of different design options and stores the alternative which produces

the least losses. The result of this parameter study together with the study of the tools

efficiency enables a number of conclusions to be drawn about what needs to be changed

in the existing tool to decrease the losses.