Check out this teardown of the CORE-PCBMotor!! I came across this motor a few months ago, after a few people who saw my design sent me their website's link. There's not much information on it and its also patented but this guy managed to take it apart and review it.

http://build-its-inprogress.blogspot.com/2018/12/core-outdoor-power-pcb-motor-teardown.html

I have no idea why they decided to use it for a lawn trimmer (there's much more interesting applications) but its very interesting to see how it was designed, the way the windings are connected and that it has sufficient torque to rotate a blade!