51222 bearing: complete specifications & equivalents

Specification table

Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-28

Parameters extracted from the official SKF Rolling Bearings catalogue (SKF PUB BU/P1 17000/1 EN (Oct 2018)); SKF® and SKF Explorer® are trademarks of AB SKF, used here for identification only — mpnbase is not an authorized SKF distributor. Boundary dimensions are ISO 15 interchangeable; current production values may differ, verify at skf.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 51222 model number is decoded

51222 is SKF's 110 mm-bore single-direction thrust ball bearing in the 51200 series to the ISO 104 dimension plan, with a flat housing seating surface, measuring 110×160×38 mm. The separable set comprises a shaft washer (ground bore, tight fit on the shaft), a loose-bore housing washer and one ball-cage assembly, reacting axial force in one direction and carrying no radial load. in the 51xxx designation the first 1 marks a single-direction bearing with a flat housing seating surface; the third digit 1–4 grades the dimension series from the light 511 section through the heavy 514 section. the final two digits 22 encode the bore as 110 mm (code 22 × 5), the standard SKF bore-code rule shared with radial bearings. with no cage suffix this is the standard execution with a stamped sheet-steel ball-cage assembly (pressed cage) — the light, quiet and economical cage for small and medium thrust-ball sizes. Envelope 110×160×38 mm (4.331×6.299×1.496 in), 25.0 mm radial section, C 125 kN, C0 365 kN, Pu 11.6 kN. reference speed 1,700 r/min (thermal) and limiting speed 2,400 r/min (mechanical), catalogue mass 2400 g. Rating split for documentation: dynamic 125 kN (L10 life), static 365 kN (safety factor s0), fatigue limit 11.6 kN (adjusted life) — three different uses of three different numbers for 51222, none interchangeable with another. Speed planning separates the two ceilings mechanically: the pressed cage and balls tolerate 2,400 r/min while thermal balance under catalogue load sets the 1,700 r/min reference; at dm ≈ 135.0 mm the corresponding dn is approximately 324k mm·r/min. Capacity density: 125 kN C from 2.400 kg of bearing steel gives about 52.1 kN per kilogram; static density is correspondingly 152.1 kN/kg at C0 365 kN. Sizing arithmetic on the 110 mm bore: 125 kN C over the 25.0 mm radial section gives 5.0 kN per section millimetre, and the 38 mm stack height is 1.52× that section — proportions typical of a 51200 thrust section. Washer-annulus check: the π/4·(D²−d²) contact annulus of 51222 covers about 10,603 mm², distributing C0 365 kN over a mean track circle of π·dm ≈ 424 mm. Execution note for this order number: the flat housing seating surface must be machined square to the shaft axis and supported across the full washer face — unlike the sphered 53-series execution this pressed-cage 51-series bearing has no self-aligning capability at all, so seat squareness is checked at mounting, not compensated in service. Inspection after removal of a 38 mm-high stack means checking both washer faces: the loose housing washer often shows the first false-brinell marks under machine vibration even though the tight shaft washer carries the rotating load of 125 kN C.

Typical equipment & failure modes

Selection pitfalls — read before you substitute

• When the housing seat cannot be machined square to the 110 mm shaft, the sphered 53-series execution of this size with its U seat washer is the self-aligning counterpart of this flat 51200 bearing.
• Keep the applied thrust above Fam ≈ A·(n·dm/1000)² with the printed factor A 0.79; for 51222 a spring preload or the rotor weight is part of the selection at light load and high speed, because unloaded balls skid rather than roll.
• Heat the shaft washer to at most 120 °C for mounting, or press it via a sleeve on its ground bore — force applied through the housing washer or the ball set brinells the 125 kN track before first rotation.
• The 51222 is a pure axial bearing: it must never be subjected to radial load — any radial force on the 110 mm shaft has to be carried by a radial bearing mounted alongside it.
• Ordering discipline for 51222: the catalogue page quotes 51222 and its 125/365 kN ratings as one exact article; bare-number substitutions from another series or brand need a fresh dimension and rating check, not a like-for-like assumption.