{HEAD ~ A spiral wrap portion} 6 is provided on {TAIL ~ the end plate} 5 so as to project axially from the surface of the end plate 5 
{ HEAD ~ A spiral wrap portion } 6 is provided on { TAIL ~ the end plate } 5 so as to project axially from the surface of the end plate 5
HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH