一種通常呈圓形的剛性部件,用於容納軸承。它用於定位軸承,但不會包裹軸承或限制軸承的運動。
flat race surface style designator, steel overall material, 2.1270 inches minimum and 2.1370 inches maximum bore diameter, 0.1230 inches minimum and 0.1260 inches maximum overall width, 2.8450 inches minimum and 2.8650 inches maximum outside diameter