magnetic pole detecting means disposed in an internal space of the housing member for detecting {HEAD ~ the position} of {TAIL ~ a magnetic pole} on the permanent magnet member 
of
magnetic pole detecting means disposed in an internal space of the housing member for detecting { HEAD ~ the position } of { TAIL ~ a magnetic pole } on the permanent magnet member
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 OTH OTH OTH OTH OTH