我们日常所见的履带式全液压挖掘机大多属于中小型机。斗容量1m3以下，功率80kw以下的为小型机；斗容量1－2．5m3，功率80－200kw的为中型机，这两类机型大约占挖掘机总数的80％。液压传动自身的特点决定了其维修保养难度要比其他传动方式大得多，并且不论是施工单位或修理单位 Most of the tracked hydraulic excavators we see on a daily basis are small and medium-sized machines. Bucket capacity below 1m3, 80kw less power for the minicomputer; fighting capacity of 1-2.5m3, power 80-200kw for the medium-sized machine, these two models about excavator accounted for about 80% of the total. Its own characteristics of hydraulic transmission determines its maintenance is much more difficult than other transmission methods, and whether it is the construction unit or repair unit