Name: BK Series
Rating: 5 (99 reviews)

NEEDLE ROLLER · DRAWN CUP · COMPACT

BK Series Needle Roller Bearing

open ends high radial load compact design

The BK Series needle roller bearings are drawn cup type bearings with open ends, designed for applications requiring high radial load capacity within a minimal radial space envelope. The one-piece drawn outer ring serves as both the raceway and the housing, eliminating the need for a separate housing bore. Precision-ground needle rollers with logarithmic profiles ensure optimal load distribution and reduced edge stresses. The bearing is supplied with a retaining spring that holds the needle set in place during handling and assembly. Operating temperature ranges from -30°C to +120°C, compatible with standard greases and oils. The BK series offers direct interchangeability with existing designs and is available in a wide range of metric sizes for use in automotive transmissions, industrial gearboxes, and compact machinery.

Space-saving design

Drawn cup construction eliminates the need for a separate housing bore, reducing overall assembly size and weight.

High radial load

Line contact between needles and raceways provides superior radial load capacity compared to ball bearings of similar dimensions.

Retaining spring

Integrated retaining spring holds the needle set securely during handling, simplifying installation and preventing roller loss.

Logarithmic profile

Optimized needle roller profile reduces edge stresses and improves load distribution, extending service life under heavy loads.

Technical specifications

Bore diameter5mm - 50mm

Outer diameter9mm - 62mm

Width range8mm - 35mm

Dynamic load rating3.2kN - 28.5kN

Static load rating4.8kN - 42.0kN

Limiting speed (grease)6000 - 18000 rpm

Limiting speed (oil)8000 - 24000 rpm

Cage typeRetaining spring

MaterialGCr15 / SAE 52100

Temperature range-30°C to +120°C

Application scenarios

Automotive transmissions

Gearbox shafts, synchronizer assemblies, and planetary gear sets requiring compact radial support.

Industrial gearboxes

High-speed and high-torque reduction units where space is limited.

Power tools

Drills, grinders, and angle grinders requiring compact high-density bearings.

Agricultural machinery

Harvester components, PTO drives, and conveyor systems.

Technical inquiries

What is the difference between BK and HK series needle bearings?

BK series bearings have open ends, allowing for through-shaft lubrication and ease of assembly. HK series bearings are closed-end bearings with a sealed bottom cap, which provides additional protection against contamination and retains lubricant.

What shaft hardness is recommended for BK series bearings?

Recommended shaft hardness is 58-62 HRC with a surface roughness Ra ≤ 0.2 µm. The shaft functions as the inner raceway, so proper hardness and finish are critical for optimal bearing performance and service life.

How should BK bearings be mounted?

Press the bearing into the housing using a mounting tool that contacts the outer ring. Ensure the housing bore is within tolerance and free of burrs. Never apply force through the needles or retaining spring.

What lubrication is recommended for BK bearings?

Use NLGI grade 2 lithium grease with EP additives for most applications. For high-speed operations, oil lubrication is preferred. Ensure lubricant reaches the needle-raceway contact surfaces before startup.

Housing bore tolerance

Recommended housing tolerance is H7 for standard applications. For high vibration environments, use P6 housing fit.

Shaft preparation

Ensure shaft is ground and hardened to 58-62 HRC with a surface finish Ra ≤ 0.2 µm. Remove sharp edges and burrs.

Storage

Store in original packaging in a dry environment with stable temperature. Avoid exposure to moisture and corrosive chemicals.

Lubrication

Apply lubricant to the shaft and needle set before assembly. For sealed applications, ensure proper grease fill volume.

Bearing Designation		Shaft Diameter（mm）	Weight(Kg)	Boundary Dimensions(mm)			Basic Load Rating(N)		Limiting Speed(rpm)
Current Code	Original Code	Shaft Diameter（mm）	Weight(Kg)	Fw	D	C	Dynamic	Static	Oil
BK0306TN		3		3	6.5	6	1320	950	6000
BK0408TN	Apr-1941	4	1.8	4	8	8	1540	1070	40000
BK0509	45941/5	5	2.1	5	9	9	2200	1790	36000
BK0608	35941/6	6	2.2	6	10	8	1830	1550	32000
BK0609	45941/6	6	2.6	6	10	9	2650	2400	30000
BK0709	45941/9	7	2.9	7	11	9	2800	2150	27000
BK0808	35941/8	8	3	8	12	8	2550	2400	21000
BK0810	88941/8	8	3.4	8	12	10	3700	3450	21000
BK08X14X10	25942/8	8	5.8	8	14	10	3800	3950	25000
BK0908	35941/9	9	3.4	9	13	8	3650	4050	25000
BK0910	55941/9	9	4.3	9	13	10	4050	4250	25000
BK0912	65941/9	9	4.9	9	13	12	5000	6000	25000
BKl010	55941/10	10	4.3	10	14	10	3900	4800	19000
BKl012	65941/10	10	5	10	14	12	5000	6300	19000
BKl015		10	6.2	10	14	15	6700	7800	19000
BKl0X16X10		10	6.8	10	16	10	6800	8800	18000
BKl210	55941/12	12	5.2	12	16	10	4150	5800	19000
BKl212	65941/12	12	6.2	12	16	12	3800	5100	15000
BKl2X18X12	35942/12K	12	10.3	12	18	12	5500	6300	17000
BKl312	BKl312	13	11.2	13	19	12	6200	7100	17000
BKl410	35941/14	14	12.1	14	20	10	6700	7000	16000
BKl512	35941/15	15	12.7	15	21	12	7000	8400	14000
BKl515		15		15	21	15	9800	11400	14000
BKl516	55941/15	15	16.5	15	21	16	9800	11400	14000
BKl522		15	22	15	21	22	10400	16500	14000
BKl612	35941/16	16	13.8	16	22	12	7100	9200	14000
BKl616	55941/16	16	17.6	16	22	16	10100	14300	14000
BKl622	85941/16	16	23.4	16	22	22	11100	17400	14000
BKl712	35941/17	17	14.5	17	23	12	6900	9300	13000
BKl716		17		17	23	16	8500	12500	10000
BKl812	35941/18	18	14.9	18	24	12	7100	9900	12000
BKl816	55941/18	18	19.9	18	24	16	10600	15300	12000
BK2010	25941/20	20	14	20	26	10	5900	7200	10000
BK2012	35941/20	20	16.7	20	26	12	7600	10100	10000
BK2016	55941/20	20	22.3	20	26	16	11700	29100	10000
BK2020	75941/20	20	27.1	20	26	20	13700	24000	10000
BK2030		20	43	20	26	30	21800	40000	10100
BK2212	35941/22	22	18.1	22	28	12	8100	10400	10100
BK2216	55941/22	22	24.3	22	28	16	11400	18100	10100
BK2220	75941/22	22	29.9	22	28	20	14500	25000	10100
BK2512	25941/25	25	23.2	25	32	12	10000	14200	9000
BK2516	5941/25	25	31	25	32	16	13600	50000	9000
BK2520	65941/25	25	38.7	25	32	20	17900	30000	9000
BK2526		25	49	25	32	26	22500	42000	9000
BK2538	85941/25	25	69	25	32	38	30000	58000	9000
BK2816	45941/28	28	34.1	28	35	16	15400	22500	8700
BK2820	65941/28	28	43	28	35	20	18900	32000	8700
BK3012	25941/30	30	27.9	30	37	12	10100	16200	8100
BK3016	45941/30	30	37.1	30	37	16	15200	27000	8100
BK3020	65941/30	30	46.5	30	37	20	19700	33500	8100
BK3026		30	59.4	30	37	26	24000	50000	8100
BK3038		30	82.5	30	37	38	32500	74000	8100
BK3512	25941/35	35	32.9	35	42	12	12100	19300	7100
BK3516	45941/35	35	43.8	35	42	16	15700	27500	7100
BK3520	65941/35	35	54.8	35	42	20	20800	41000	7100
BK3530		35		35	42	30
BK4012	25941/40	40	38.2	40	47	12	14000	24300	6300
BK4016	45941/40	40	51	40	47	16	20000	38500	6300
BK4020	65941/40	40	62	40	47	20	25500	52000	6300
BK4512	25941/45	45	45	45	52	12	12900	22500	5800
BK4516	45941/45	45	56	45	52	16	19300	38000	5800
BK4520	65941/45	45	72	45	52	20	22000	51000	5800
BK5020	55941/50	50	87.3	50	58	20	28000	60000	5300
BK5025	5943/50	50	109	50	58	25	34500	80000	5300
BK5520	55941/55	55	93.8	55	63	20	29500	59900	4600
BK5528	85941/55	55	132	55	63	28	39090	98000	4600
BK6012		60	77	60	68	12	12400	29000	4100
BK6020	55941/60	60	105	60	68	20	30500	72000	4100
BK6032	85941/60	60	164	60	68	32	50000	131000	4100

BK Series

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