INA SX0118 swing bearing excavator has no tooth type, outside tooth type and within tooth type of four points contact ball bearing, and double row angle contact type ball bearing cross cylindrical roll child bearing, and cross cone roll child bearing and three row cylindrical roll child composite bearing four a series, which four points contact ball bearing has higher of static load ability, cross cylindrical roll child has taught high of dynamic load ability, cross cone roll child bearing of pre - had full can makes bearing has larger of support rigid and Rotary precision, three row cylindrical roll child combination bearing because hosted ability of improve leads bearing height, various forces respectively by different roll road bear, so also by force situation, its bearing diameter can greatly narrow, thus has makes host more compact of features is a high hosted ability of Rotary supporting bearing.