The internal gear is made of an elastic resin and is separated from the casing of the system or {HEAD ~ a metal ring} fitted in the casing by {TAIL ~ a predetermined gap} 
The internal gear is made of an elastic resin and is separated from the casing of the system or { HEAD ~ a metal ring } fitted in the casing by { TAIL ~ a predetermined gap }
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 HEAD REL OTH OTH OTH REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL