The pair of shielding plates 17 and 18 divides {TAIL ~ the inside} of the outer cylindrical casing 4 in {HEAD ~ front} and rear and is provided with one or more air holes 15 and 16 at the outer circumferential section or at the central section 
The pair of shielding plates 17 and 18 divides { TAIL ~ the inside } of the outer cylindrical casing 4 in { HEAD ~ front } and rear and is provided with one or more air holes 15 and 16 at the outer circumferential section or at the central section
OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH