That with inner ring and without ring. The center shaft is used as rolling body tray for those without inner ring so that its size is even smaller.
Detailed introduction to Needle roller bearings with inner ring:
RTL entity bushed needle roller bearing is a kind of high capacity bearing with small sectional height. It can operate very flexibly even with the light alloy bearing seat due to its high hard outer ring. There are two series : metric and inch series . Both of which are structured with retainer, full needle and sealing types. Besides, the entity bushed needle roller bearings are divided into two kinds : that with inner ring and without ring. The center shaft is used as rolling body tray for those without inner ring so that its size is even smaller
Needle roller bearings without inner ring includes NK, NKS, RNA48, RNA49 RNA69 , RNA0 series. The rolling needles roll directly
on the quenched and ground shaft. The needle bearings without inner ring are compact in structure. The rotating precision will be increased
if the shaft is machined with high precision. For those needle bearings without retaining edge or inner ring (RNAO), the outer ring and need-
le unit can not be exchanged.