In {TAIL ~ this case}, {HEAD ~ the gap} 23 is provided between the internal gear 3 and the iron ring 22 as shown in FIG 2 
In
In { TAIL ~ this case } , { HEAD ~ the gap } 23 is provided between the internal gear 3 and the iron ring 22 as shown in FIG 2
REL TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH