A planetary gear reduction system 5, wherein said casing includes a first member and {TAIL ~ a second member} abutting opposing ones of said axial ends of {HEAD ~ said internal gear} 
A planetary gear reduction system 5 , wherein said casing includes a first member and { TAIL ~ a second member } abutting opposing ones of said axial ends of { HEAD ~ said internal gear }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD