This kind of self-lubricating plain radial bearing (maintenance-free) is covered with specific PTFE sliding layer. Its outer ring sphere is bonded with special self-lubricating materials which will not only form a slide for the outer ring, but will deliver load and offer self-lubricating function. If only be added with lubricating oil, such bearing may endure forever. Thereof, the GE...XT, GEC...XT, and GEH...XT series may be divided into the bearings with small clamping rings and the bearings with large clamping rings. It is worth noting that some bearings are locked by the clamping rings. The outer rings of the GE...DW, GEP...FS and GEH...HCS series adopt 42GrcMo radial subdivision, using bolt for fixing and pin for locking at one side.