Needle Roller Bearings

I. Basic Part-Number Composition (National Standard + General Industry Practice)

1) Drawn-cup (thin-wall) needle roller bearings

HK: Open-end type (through-bore, both ends open)

BK: Closed-end type (one end capped)

2) Machined-ring needle roller bearings

NA: With inner ring, flanged outer ring

NK: Without inner ring, flanged outer ring

NKI: With inner ring, flanged outer ring (alternative product series)

3) Needle roller and cage assemblies (no inner / outer rings)

K: Example K25×30×20 → bore 25 mm, outer diameter 30 mm, width 20 mm

4) Thrust needle roller bearings

AXK: Thrust needle-roller & cage assembly; AXK2035 → bore 20 mm, outer diameter 35 mm

AS: Thrust washer; AS2035 matches AXK2035

5) Common suffix codes

2RS: Double-sided seals; RS: Single-sided seal

ZW: Double-row; TN: Nylon cage

II. Rapid-Selection Guidelines

1. Extremely limited radial installation space → select HK / BK (drawn-cup bearings).
2. Inner ring required; shaft surface has poor wear resistance → select NA / NKI (with inner ring).
3. Hardened shaft and outer housing bore already available → select K-type roller-cage assembly.
4. Axial load carrying requirement → use AXK assembly together with AS thrust washers.

III.Main Applications

For heavy radial loads with limited radial space: Gearboxes and transmissions Automotive piston pins, connectingrod mechanisms Universal joints, clutches Engineering machinery, hydraulic pumps Textile machinery Hinge pins, swing arms, rocker mechanisms Various shortstroke oscillating components.

Model	Fw/d(mm)	D(mm)	C(mm)	Cr(kN)	Cor(kN)	Grease (r/min)	Oil (r/min)	W(kg)
NA4900	10	22	13	12.2	12.5	15000	20000	0.022
NA4901	12	24	13	13.2	14.2	14000	19000	0.024
NA4902	15	28	13	15.8	18.5	13000	17000	0.030
NA4903	17	30	13	16.5	20.5	12000	16000	0.033
NA4904	20	37	17	24.5	30.5	10000	14000	0.064
NA4905	25	42	17	27.2	35.2	9000	12000	0.074
NA4906	30	47	17	29.0	40.8	8000	11000	0.084
NA4907	35	55	20	39.0	55.0	7000	9500	0.130
NK20/16	20	28	16	18.8	24.8	11000	15000	0.028
NK25/20	25	33	20	27.5	37.2	9500	13000	0.045
NK30/20	30	38	20	29.2	42.0	8500	11000	0.052
NK35/20	35	45	20	33.5	52.8	7500	10000	0.078
HK1010	10	14	10	2.41	2.33	14000	18000	0.004
HK1212	12	18	12	4.65	4.80	12000	16000	0.008
HK1516	15	21	16	7.80	9.20	10000	14000	0.013
HK1616	16	22	16	10.5	15.6	9500	13000	0.015
HK2016	20	26	16	11.2	14.8	8500	11000	0.018
HK2520	25	32	20	16.8	24.5	7000	9500	0.032
HK3020	30	38	20	19.5	30.2	6300	8500	0.040