NKX25 Z Combined Needle Roller Bearings 25×37×30mm

 Combined needle roller bearings are singe directional positioning bearings or the positioning bearings with minimum radically sectional height.If the centripetal needle bearings are used with thrust ball bearings or cylindrical roller bearings in combination,the applicable range will be greatly expanded.These bearings are mainly used in transmission engineering and tooling machines such as the bearings in the main shaft of drill press,drill sleeve,positioning central shaft,worm,spanner teeth head and so on.

The dimensional tolerance and geometric precision are in compliance with DIN620 and the tolerance grade of P0 with normal radial gap Co.The only exception is NKIB series which have narrower inner aperture with bigger tolerance so that they can be used with the shaft with K5 tolerance in transit combination.

If the bearings combination of high precision,the listed bearings in compliance DIN620 P6 and P5 grades tolerance can be supplied.

RNB Combined Needle Roller Bearings consist of:

Needle Roller/Axial Deep Groove Ball Bearings,NX,NX…Z,NKX and NKX…Z Series

Needle Roller/Axial Cylindrical Roller Bearings,NKXR,NKXR…Z Series

Needle Roller/Angular Contact Ball Bearings,NKIA,NKIB Series

Needle Roller/Axial Deep Groove Ball Bearings

  Needle roller/axial deep groove ball bearings do not have an inner ring and are therefore particularly compact in a radial direction.However,they require a shaft raceway that is hardened and ground.

  Series NX and NX…Z have a full complement comprising a ball bearings component and end caps,Series NKX and NKX…Z have an axial bearings component comprising a ball and cage assembly with a sheet steel or plastic cage. NKX…Z also has an end cap on the axial bearings component.

   For lubrication, the outer ring has a lubricated groove and lubrication holes.NX and NKX series are lubricated with oil,but NX…Z and NKX…Z are lubricated with grease the end cap in NX has lubrication holes,but the end cap in NKX…Z do not have lubrication holes.

   If Needle roller/axial deep groove ball bearings are fitted oppositely,alternative axial loads can be sustained. It is suggested to pre-tighten the bearings without load,but with springs.In this way,the heat expansion can be compensated and the operational noise can be lowered. When the speed is greater than 0.2n 1 oil,the pre-tightening value should be 1% to 2% of the axial rated dynamic load.

2) Needle Roller/Axial Cylindrical Roller Bearings

   Needle roller/axial cylindrical roller bearings do not have an inner ring and are therefore particularly compact in a radial direction.However,they require a shaft raceway that is hardened and ground.

   Series NKXR and NKXR…Z have an axial bearings component comprising a roller and cage assembly with a plastic cage.NKXR…Z also has an end cap on the axial bearings component.

   For lubrication,the outer ring has a lubrication groove and lubrication holes.NKXR is lubricated with oil.NKXR…Z is intended for grease lubrication.The end cap does not have lubrication holes.

3)Needle Roller/Angular Contact Ball Bearings

   Combined bearings NKIA and NKIB have an inner ring

   Series NKIA corresponds to DIN5429-2.It can support axial loads from one direction.

   Series NKIB has one narrow inner ring and one wide inner ring.The axial bearings component has plastic ball cage,permissible operational temperature 120℃,150℃ for temporary use,180℃ for short time only. At the point where the inner rings join,there is a shoulder on both sides for guidance of the ball and cage assembly.As a result,these bearings are also suitable for supporting axial forces alternating in direction.The bearings guide the shaft with an axial clearance of 0.08mm to 0.25mm.

   NKIA and NKIB can be lubricated with grease or oil.For lubrication,the outer ring has a lubrication groove and lubrication hole.