挖掘机动臂下轴套支承孔是承受外力较大、作业环境又比较恶劣的部位，故长期使用后支承孔出现的变形较大，若再加之保养不当、维修不及时，就易出现轴套外圆松动、过度磨损的现象，从而使动臂下轴套支承孔损坏。其损坏状况一般为：靠近铲斗的部位磨损量较大，而离铲斗较远的部 Excavator boom under the bearing sleeve is to withstand the larger external force, the working environment and the more bad parts, so after long-term use of bearing holes appear larger deformation, if coupled with improper maintenance, maintenance is not timely, easy to appear sleeve Loose outer ring, excessive wear phenomenon, so that the lower boom bearing hole damage. The damage situation is generally: the part near the bucket has a large amount of wear, and the part far from the bucket