UCFLX09 bearing: complete specifications & equivalents
The UCFLX09 is a JIS B 1559 radial bearing sized 45 x 100 x 51.6 mm (bore x OD x width) with 2RS sealing. Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 45 mm |
| Outer diameter D | 100 mm |
| Width B | 51.6 mm |
| Seal / shield | 2RS |
| Basic dynamic load rating C | 39 kN |
| Basic static load rating C0 | 23.2 kN |
| Fatigue load limit Pu | 1.82 kN |
| Mass | 2200 g |
| Housing height H | 189 mm |
| Housing overall length L | 116 mm |
| Mounting bolt center distance J | 157 mm |
| Mounting hole diameter N | 16 mm |
| Manufacturer designation | UCFLX09 |
| Standard | JIS B 1559 |
| Catalog version | CAT. No. 2203-3/E 2024 |
| Last verified | 2026-09-25 |
Source: catalog reference (CAT. No. 2203-3/E 2024) · extracted 2026-09-25
Parameters extracted from the official NTN Ball and Roller Bearings catalogue (CAT. No. 2203-3/E 2024); 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.
Dimensions in inches & UCFL-series range
| Bore d | 1.772 in |
|---|---|
| Outer diameter D | 3.937 in |
| Width B | 2.031 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 27.5 mm |
| Smallest bore in UCFL-series | 12 mm |
| Largest outer diameter in UCFL-series | 300 mm |
| Width range across UCFL-series | 31–145 mm |
| Bore position in UCFL-series (smallest first) | 9 of 25 |
| Bore above smallest UCFL-series size | 33 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| UCFLX09 | ISO 15 | verify Commonly quoted cross reference; confirm against the target catalog before ordering. | ISO 15 boundary-dimension envelope; seal suffix convention varies by brand (2RS / DDU / LLU / 2RSR) — verify seal design and temperature range. Brand-specific OEM equivalents pending multi-source data. |
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 UCFLX09 model number is decoded
The NTN UCFLX09 flanged unit combines a sealed UCX09D1 insert with a diamond-shaped FLX09 cast-iron housing that bolts flat against a machine frame. The code breaks down as insert family UC, housing form FL (flange), duty series X, bore code ending in the 45 mm shaft size; the unit is built from insert UCX09D1 and housing FLX09. For the frame-face drawing of UCFLX09: the two holes are 157 mm apart (J), the rhombus spans 116 mm (L) and 189 mm (H), and M14 (16 mm) bolts clamp it around the 45 mm shaft. The X section is NTN’s intermediate-duty build: a wider UCX insert with a higher rating sits in a longer, sturdier housing than the 2-series unit at the same bore. The diamond flange carries the shaft square to a vertical face — a welded frame, side plate or gearbox wall — so no base plinth and no shim pack under the bearing are required. The 25–50 mm bore band is the workhorse of industry — belt conveyors, fans, agricultural drives and small process machines — which is why this range has the fullest choice of series and cover options. HVAC air-handling units carry fan shafts on this size, usually in warm roof-space air where the grease must be rated for continuous ambient temperature rather than load. On V-belt drives, align the pulleys before finally tightening the feet; the spherical seat lets you rotate the unit, but sliding the whole base on the foundation is what removes the belt-edge wear. Basic ratings of the UCX09D1 insert are 39 kN dynamic and 23.2 kN static; the assembled UCFLX09 weighs about 2.2 kg.
Typical equipment & failure modes
Common applications
- industrial fans and blowers
- agricultural augers and bucket elevators
- small crushers and screening feeds
- long line-shafting where several units must share a straight reference
Known failure patterns
- grease starvation on long intervals in hot positions, with the ball set running on dried thickener
- fretting corrosion of the shaft journal under the wide inner ring after years of micro-creep
- lip-seal failure from grit past the slinger, followed by grease loss and abrasive wear
Selection pitfalls — read before you substitute
- The X insert of UCFLX09 is wider and rated above the 2-series part at 45 mm, but it is not interchangeable with a 3-series unit in a damaged application — check the housing length and bolt centres before swapping.
- As a rhombus flange, UCFLX09 pulls against the frame through only two M14 bolts on 157 mm centres; the mounting plate must be stiff enough not to bend between them under belt load.
- The D1 suffix on UCX09D1 means the greasable execution; a unit without it has no fitting path, so do not assume every UCFLX09 on site accepts relubrication.
- Self-aligning is not the same as free to move: the UCX09D1 insert of UCFLX09 pivots to correct static misalignment, but a continuously bending shaft still frets the spherical seat.
- In this bore band the temptation is to choose UCFLX09 on shaft size alone; belt pull often dominates the radial load, so rate the unit against the overhung pulley force, not just transmitted power.
Frequently asked questions
What are the dimensions of an UCFLX09 mounted bearing?
UCFLX09 takes a 45 mm shaft (insert UCX09D1, 100 mm OD) and has a unit mass of about 2.2 kg. Flange figures: height H 189 mm, length L 116 mm, bolt centres J 157 mm, holes 16 mm for M14 bolts.
What does the UCFLX09 designation mean?
UC identifies the wide-inner-ring, setscrew-locking ball bearing insert; FL the two-bolt rhombus flange housing; X is the duty series; the last digits encode the 45 mm bore. UCFLX09 is built from housing FLX09 plus insert UCX09D1 (D1 = greasable).
How is UCFLX09 locked to the shaft, and how tight should the setscrews be?
The UCX09D1 insert uses two collar setscrews on the 45 mm shaft. Tighten them to NTN's torque table for this bore size in sequence — half torque on the first, full on the second, then back to the first — and re-torque after the first 24–48 running hours once the collar has seated.
When should I choose a rhombus flange unit like UCFLX09 instead of a pillow block?
Choose the UCFLX09 two-bolt flange when the 45 mm shaft meets a vertical frame or side plate: the diamond housing bolts flush with two M14 bolts on 157 mm centres. A UCP pillow block is used when the shaft runs above a horizontal mounting surface.
How often should I relubricate an UCFLX09 unit?
There is no single interval for UCFLX09: the UCX09D1 insert is regreased through the D1 fitting while the shaft turns, using an NLGI 2 lithium or lithium-complex grease. Quarterly is typical for normal ambient conveyor duty; shorten to weekly or monthly where temperatures exceed about 70 °C, water is present, or dust is heavy.
Reviewed & verified by the MPN Base engineering desk against source catalog CAT. No. 2203-3/E 2024 on 2026-09-25. Read our editorial & correction policy.