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。
0.0300 inches minimum and 0.0320 inches maximum overall width, steel overall material, 0.2520 inches minimum and 0.2620 inches maximum bore diameter, 0.6570 inches minimum and 0.6770 inches maximum outside diameter, flat race surface style designator