This work presents a novel design procedure for integrating electric motors
with gear mechanisms. Based on the configurations of electric motors and the
kinematic structure of gear trains, the design requirements and constraints are
concluded. By applying the graph representations and creative mechanism
design methodology, feasible design concepts are successfully generated
systematically. The open-circuit magnetostatic field analysis of a DC
commutator motor conducted by applying 1-D and 2-D equivalent magnetic
circuit methods are obtained and verified using FEA. The differences in the
air-gap flux density are 3.21% and 3.06% for 1-D and 2-D methods, respectively.
The Carter’s coefficient is applied to model the permeance of the slot and
gear-teeth space. The affection of the integrated gear-teeth on the flux linkage
and the first derivative of the flux linkage can be ignored. The design methods
for gear trains, gear profiles, number of gear teeth, and gear strength are also
introduced. The maximum stress of the gear profile is 312 MPa, and the results
show that the gear train can be used for transmission purposes. A DC
commutator motor with a planetary gear mechanism and an AC induction motor
with an ordinary gear train are applied as examples. A feasible integrated DC
commutator motor device is presented that reduces the cogging torque and the
torque ripple by 92.02% and 50.14%, respectively, while increasing the torque
density by 16.66%. The torque of the AC induction motor is reduced by 8.96%,
and the torque ripple is reduced by 14.23%. In addition, the torque density is
increased by 1.75%. This indicates that the integrated devices provide more
stable and efficiency output torque than the existing design.