QJ-220-N2MA bearing: complete specifications & equivalents
The QJ-220-N2MA is a ISO 15 radial bearing sized 100 x 180 x 34 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | SKF |
| Bore diameter d | 100 mm |
| Outer diameter D | 180 mm |
| Width B | 34 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass |
| Basic dynamic load rating C | 236 kN |
| Basic static load rating C0 | 265 kN |
| Fatigue load limit Pu | 9.5 kN |
| Limiting speed (mechanical) | 6300 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 4050 g |
| Manufacturer designation | QJ 220 N2MA |
| Standard | ISO 15 |
| Catalog version | SKF PUB BU/P1 17000/1 EN (Oct 2018) |
| Last verified | 2026-09-27 |
Source: catalog reference (SKF PUB BU/P1 17000/1 EN (Oct 2018)) · extracted 2026-09-27
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.
Dimensions in inches & QJ200-series range
| Bore d | 3.937 in |
|---|---|
| Outer diameter D | 7.087 in |
| Width B | 1.339 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 40 mm |
| Smallest bore in QJ200-series | 15 mm |
| Largest outer diameter in QJ200-series | 360 mm |
| Width range across QJ200-series | 11–58 mm |
| Bore position in QJ200-series (smallest first) | 18 of 29 |
| Bore above smallest QJ200-series size | 85 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 7220-BEP | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×180×34 mm envelope, but catalogue C/C0 differ between executions (236/265 kN vs 135/122 kN) — boundary dimensions match, not a load-rating equivalent. |
| 7220-BECBP | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×180×34 mm envelope, but catalogue C/C0 differ between executions (236/265 kN vs 143/134 kN) — boundary dimensions match, not a load-rating equivalent. |
| 7220-BECBY | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×180×34 mm envelope, but catalogue C/C0 differ between executions (236/265 kN vs 143/134 kN) — boundary dimensions match, not a load-rating equivalent. |
| 7220-BECBM | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same 100×180×34 mm envelope, but catalogue C/C0 differ between executions (236/265 kN vs 143/134 kN) — boundary dimensions match, not a load-rating equivalent. |
| 7220 | SKF | partial Main dimensions match; tolerances, seals or internal clearance differ. | SKF SKF 7220 BEP shares the 100×180×34 mm angular-contact envelope, but catalogue C/C0 differ (236/265 kN vs 135/122 kN) — envelope match, not a load-rating equivalent. |
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 QJ-220-N2MA model number is decoded
QJ 220 N2MA is SKF's 100 mm-bore QJ four-point contact ball bearing of the QJ200 series, 100×180×34 mm, with a two-piece inner ring for bidirectional axial location beside a radial bearing. QJ identifies a four-point contact ball bearing with a two-piece inner ring: the gothic-arch raceways seat each ball at four points, giving axial location in both directions while a paired radial bearing carries the radial load. N2 marks two locating slots, 180° apart, in one outer-ring side face: pins or dogs engage the slots to stop the outer ring turning in its radially-clear housing bore. machined brass cage, outer-ring-centred (suffix MA), which guides on the outer ring rather than on the balls. Envelope 100×180×34 mm (3.937×7.087×1.339 in), 40.0 mm radial section height, C 236 kN, C0 265 kN, Pu 9.5 kN.SKF publishes only the 6,300 r/min limiting speed for this execution, catalogue mass 4050 g. Sizing arithmetic on the 100 mm bore: 236 kN C divided by the 40.0 mm radial section height gives 5.9 kN per section millimetre; the 4050 g mass and 4 % Pu/C share frame the light-load floor for the adjusted-life check. The 9.5 kN fatigue load limit is the equivalent-load floor for long-life adjustment; with 236/265 kN ratings and 4050 g mass this execution carries about 2.36 kN of C per millimetre of bore. Speed-ratio note for this exact unit: no thermal reference speed is listed (seal/grease life governs), so the 6,300 r/min limiting value is the single published ceiling. Locating-slot execution: the two N2 notches are milled into one outer-ring side face exactly 180 degrees apart and engaged by housing dogs or headed pins during assembly; verify dog engagement by hand before the cover goes on, deburr the slot edges after any housing rework, and re-inspect the slot roots for fretting marks at each overhaul because a dog that rides only one slot lets the outer ring walk. The slots identify this order number unmistakably: the plain MA/PHAS execution of the same bore has no notches and must be secured differently.
Typical equipment & failure modes
Common applications
- heavy gearbox locating positions
- screw conveyor and extruder thrust positions
- crane travel and hoist drives
Known failure patterns
- cage wear from speed above the limiting value with thin or aged lubricant
- ball skidding when the Fa/Fr 1,27 load-ratio condition is not met and the balls contact both sides of one raceway
- locating-slot root fretting or dog wear when only one N2 notch carries the anti-rotation torque
- fretting corrosion on a loose rotating shaft seat
- rolling-contact fatigue spalling after the rated L10 life is exceeded
Selection pitfalls — read before you substitute
- Provide a minimum axial load (spring preload is common) so the balls stay correctly seated at speed and light-load conditions; otherwise they skid.
- Engage the N2 slots with housing dogs at assembly — a radially loose outer ring without positive anti-rotation creeps its seat
- Apply the Fa/Fr ≥ 1,27 condition: at lower ratios the balls contact both sides of a raceway, increasing friction and shortening life — the paired radial bearing should carry the radial share.
- Anti-rotation is built into QJ-220-N2MA: check the two N2 slot faces and the engaging housing dogs at every refit, and never rely on cover friction to stop the radially loose outer ring.
- The MA brass cage of QJ-220-N2MA is outer-ring-centred: its guide land needs an uninterrupted oil film, so check lubricant reach when the bearing is used purely as a thrust location.
- Catalogue ratings are SKF PUB BU/P1 17000 figures for QJ 220 N2MA as the qj slotted execution; the other order numbers of the QJ 220 size are different products and may carry different ratings — always quote the full designation when purchasing.
Frequently asked questions
What are the dimensions and catalogue data of QJ-220-N2MA?
QJ 220 N2MA measures 100 mm bore × 180 mm OD × 34 mm width (3.937 × 7.087 × 1.339 in), mass about 4050 g. SKF 17000 ratings: C 236 kN, C0 265 kN, Pu 9.5 kN, SKF publishes only the 6,300 r/min limiting speed for this execution.
What does the N2MA suffix mean?
QJ identifies a four-point contact ball bearing with a two-piece inner ring: the gothic-arch raceways seat each ball at four points, giving axial location in both directions while a paired radial bearing carries the radial load. N2 marks two locating slots, 180° apart, in one outer-ring side face: pins or dogs engage the slots to stop the outer ring turning in its radially-clear housing bore. machined brass cage, outer-ring-centred (suffix MA), which guides on the outer ring rather than on the balls.
How is a QJ four-point bearing mounted?
As a thrust/locating bearing with radial clearance in the housing, paired with a separate radial bearing (commonly a cylindrical roller bearing): the QJ locates the shaft axially in both directions, the radial bearing carries radial load. Keep the outer ring unclamped with a small end-play gap; N2 slot executions use dogs to stop the outer ring turning.
What does QJ mean in QJ 220 N2MA?
QJ is SKF's four-point contact design: a two-piece inner ring and gothic-arch raceways so each ball contacts at four points, giving bidirectional axial location with limited radial capacity — it must see Fa/Fr ≥ 1,27 for correct ball contact.
Reviewed & verified by the MPN Base engineering desk against source catalog SKF PUB BU/P1 17000/1 EN (Oct 2018) on 2026-09-27. Read our editorial & correction policy.