a surface length of each of the stator teeth is greater than a sum of a stroke length of the motor and an axial thickness of one of {HEAD ~ the magnets} in {TAIL ~ the buried magnet system}, and 
a surface length of each of the stator teeth is greater than a sum of a stroke length of the motor and an axial thickness of one of { HEAD ~ the magnets } in { TAIL ~ the buried magnet system } , and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH