短語詞組短語roller r bit 牙輪鉆頭roller bearing bit 滾柱軸承鉆頭roller cone bit 牙輪鉆頭roller cutter bit 牙輪鉆頭cross roller rock bit 十字形四牙輪鉆頭sealed roller bearing bit 密封滾動(dòng)軸承鉆頭roller core bit 取心牙輪鉆頭roller -bit hole rig 牙輪鉆機(jī) 返回 roller bit