Structure

The retaining edge of HSB entity bushed needle roller bearing is on the outer ring. It can either fixed or spring lock ring. If the center shaft tray is quenched and ground, the dismountable inner ring can be cancelled. Generally there are one row needle roller which includes NK1,NK1S,NA48,NA49 series needle roller bearings, NA69 series bearings. all those with aperture diameter over 32 mm are double row needle roller bearings. There are oil groove or holes on the outer ring which make HSB needle roller bearing easy for lubricating. Only NK1 series and the small sized NK 19/16, NK12/16 have neither oil groove nor oil hole. NA49 series bearing have an oil hole on the inner ring. NA49 series HSB needle roller bearings are either one side sealed (RS) or double sides sealed (2RS).

HSB needle roller bearings without retaining edge is NAO series which have got a smaller needle retainer assembly than the bearing outer ring. Thus, the needle unit can move freely after the bearings are fitted. The axial guidance of the needle unit requires a positioning face on the side. There is a oil groove, a oil hole and two rows of needles in the needle outer ring of wide series, but no oil groove and oil hole in the narrow series which has only one row of bearing unit.

Needle roller bearings without inner ring includes NK,NKS,RNA48,RNA49,RNA69,RNAO series. The rolling needles roll directly on the quenched and ground shaft. The needle bearings without inner ring are compact in structrue. 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 needle unit can not be exchanged.

The sealed needle roller bearings are filled with lithium based grease. For more effective functioning of the sealing in axle movement, there will be no guiding slope on the inner ring which is 1mm higher than outer ring. Ordinary sealed bearings will operate in the temperature range of-30ºC-120ºC.

The inner ring of IR series is quenched and made with high precision. The dimensional tolerance and the geometric precision of the standard grade inner ring is in compliance with PO grade. In using HSB needle roller bearings, the selection of HSB inner ring will enable the bearing to keep a normal operational backlash.

Standard clearance of HSB needle roller bearings is in CO group. For special requirements, clearance of C2,C3 and C4 can be supplied. When HSB needle bearing is mounted in parallel, they should have the same radical clearances so that the load can be distributed evenly.

In general case, the mounting of the needle roller bearings needs compact combination so that the thin wall bush can be well supported. The heavier the load is , the selection combination is bigger, especially when impact load should be considered. Furthermore,it is necessary to consider the combination of materials and tempoeratuer differences.