NU322 bearing: complete specifications & equivalents

Specification table

Source: catalog reference (NTN Ball and Roller Bearings CAT.No.2203E) · extracted 2026-10-01

Parameters extracted from the official NTN Ball and Roller Bearings catalogue (NTN Ball and Roller Bearings CAT.No.2203E); NTN® is a trademark of NTN Corporation, used here for identification only — mpnbase is not an authorized NTN distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at ntnglobal.com.

Cross references & equivalents

Interchange levels: full standard interchange · partial verify parameters · verify manual confirmation required. Links resolve to the equivalent model's specification page where available.

How the NU322 model number is decoded

For pure radial duty on a 110 mm shaft NTN supplies NU322: two integral ribs on the outer ring and a ribless, separable inner ring; the open execution is rated 3,000 r/min on grease and 3,500 r/min on oil. The leading NU defines the rib arrangement (outer ring ribbed, inner ring ribless); the dimension-series digits and the two-digit bore code resolve to 110 mm, with 240 mm OD and 50 mm width from the ISO 15 general plan. With C 395 kN and C0 400 kN (C0/C ≈ 1.01) the bearing is proportioned for heavy radial load; the NU design carries no axial load and floats axially on both sides. With the inner ring rotating, catalogue practice is a m6/n6 shaft seat and an H7/H6 housing; the outer ring must remain free to creep slightly axially in non-locating NU arrangements. Keep the open bearing wrapped until fitting: the line-contact raceways of the 110 mm bore indent under a single hard particle, and the steel cage provides no sealing of its own.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• Induction-heat the 110 mm inner ring (max 120 °C) and mount it before fitting the outer ring; the ring mass makes square guidance essential — driving through the rollers brinells the 240 mm raceway.
• If the shaft must be located both ways, do not use NU322 alone: pair it with a locating bearing or specify the NUP execution with the matching loose rib ring from the 2203E table.
• Do not replace NU322 with a deep-groove ball bearing on rating alone: line contact gives 395 kN radial capacity but the bearing cannot carry the thrust duty a ball bearing can and misalignment tolerance is only 3–4 arc-minutes.
• The NU rib arrangement is not interchangeable with another prefix on the same 110 mm seat: outer ring ribbed, inner ring ribless. Swapping NU for NJ changes axial location behaviour even though the 240×50 mm envelope matches.
• Minimum radial load is frequently missed in oversized motor and fan selections: an underloaded NU322 skids at 3,000 r/min and fails by smearing long before L10 fatigue.
• The 395/400 kN ratings, 41.5 kN Pu and 9770 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for NU322 (standard execution); other makes sharing the ISO 15 envelope revise internal geometry without changing the order number, so keep the 2203E reference with the specification for critical drives.