NSKHR32015XJSingle-Row Tapered Roller Bearing — 75 x 115 x 25 mm, High-Capacity HR Design, Steel Cage, Complete Cone and Cup

Product Description

What this part is

An NSK single-row metric tapered roller bearing, HR32015XJ, in the 320 series. Tapered rollers run between a tapered inner ring (the cone, with its integral rib and roller cage) and a tapered outer ring (the cup). Because the raceways are conical, the bearing carries a heavy radial load and a heavy thrust load in one direction simultaneously, and it is normally mounted in an opposed pair so the two bearings restrain thrust in both directions.

Decoding the designation

HR is NSK’s high-capacity tapered roller design — an improved internal geometry and roller complement giving higher ratings than the plain 32015X in the same envelope, so HR32015XJ and 32015X are the same size but not the same rating. 320 is the ISO dimension series, 15 the bore code, giving a 75 mm bore. X marks the ISO 355 revised contact-angle and dimension standard. J is the cage: a pressed steel cage. Written variously as HR-32015-X-J, HR32015X, 32015XJ and 32015X.

Scope — what is in the box

The complete bearing: cone assembly (inner ring, rollers and cage) together with its matched cup. That matters on tapered roller bearings, because cone and cup are separable and are frequently sold as individual components — a cone on its own will not run without its cup, and a cup on its own is only useful if you already have the matching cone. No spacers, no seals and no adapter sleeve are included; this is an open bearing that relies on the housing for sealing.

Published specifications

Bore (d): 75 mmOutside diameter (D): 115 mmAssembled width (T): 25 mmCup (outer ring) width: 19 mmRows: 1Cage: pressed steel (J)Closure: open, no sealBasic dynamic load rating Cr: 109,000 N (109 kN)Basic static load rating Cor: 171,000 N (171 kN)Limiting speed, grease lubrication: 3,000 rpmLimiting speed, oil lubrication: 4,000 rpmDesign: NSK HR high-capacity tapered rollerStandard: ISO 355 (X) dimension and contact angle series

What these specs mean in practice

The static rating being well above the dynamic rating is normal and expected on a tapered roller bearing — the rollers are in line contact, so the bearing shrugs off shock and standing load far better than it tolerates high-speed running. 3,000 rpm on grease is the practical ceiling; take it to oil and 4,000 rpm before considering a different bearing type. Because the HR design is a capacity uprate inside the standard 32015X envelope, it drops into an existing 32015X housing and shaft without machining, and buys margin on a duty that has been failing bearings. Note that a tapered roller bearing has no internal clearance until it is set — endplay or preload is established at assembly by the position of the opposed bearing, and getting that setting wrong is the most common cause of premature failure on this bearing type.

Fitting notes

Mount the cup and the cone separately, each square in its seat, and never press a bearing home through the rollers. Set endplay or preload by measurement, not by feel: too much endplay lets the rollers skid and spall, too much preload runs the bearing hot. Fill the cone with grease by hand between the rollers and the rib before closing the housing — the rib is where a starved tapered roller bearing scuffs first. If the pair is a matched opposed set, keep the cones and cups together and do not mix cups between bearings.

Interchange guidance

The ISO base number is 32015X, and 32015X bearings from Timken, SKF, FAG, Koyo, NTN and Nachi share the 75 x 115 x 25 mm envelope, so they are dimensionally interchangeable. The HR prefix is NSK’s own capacity uprate, so a plain 32015X is a dimensional fit but a lower-rated part — treat it as a related size, not an equal. The J steel cage is standard; other cage codes in this series are different parts. Do not confuse this with 32015 (without the X), which belongs to the older pre-ISO 355 dimension standard and has a different contact angle and width relationship.