23934EMD1 bearing: complete specifications & equivalents
The 23934EMD1 is a ISO 15 radial bearing sized 170 x 230 x 45 mm (bore x OD x width). Verify dimensions against the official catalog before ordering.
Specification table
| Parameter | Value |
|---|---|
| Brand | NTN |
| Bore diameter d | 170 mm |
| Outer diameter D | 230 mm |
| Width B | 45 mm |
| Material | GCr15 |
| Seal / shield | open |
| Internal clearance | CN |
| Tolerance class | P0 |
| Cage | brass, machined (M1) |
| Basic dynamic load rating C | 468 kN |
| Basic static load rating C0 | 723 kN |
| Fatigue load limit Pu | 48.8 kN |
| Limiting speed (mechanical) | 1800 rpm |
| Operating temperature | -40 to +120 °C |
| Mass | 5390 g |
| Manufacturer designation | NTN 23934EMD1 |
| Standard | ISO 15 |
| Catalog version | NTN Ball and Roller Bearings CAT.No.2203E |
| Last verified | 2026-10-01 |
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.
Dimensions in inches & 23900-series range
| Bore d | 6.693 in |
|---|---|
| Outer diameter D | 9.055 in |
| Width B | 1.772 in |
| ISO bore code | — |
| Radial section height (D−d)/2 | 30 mm |
| Smallest bore in 23900-series | 160 mm |
| Largest outer diameter in 23900-series | 1820 mm |
| Width range across 23900-series | 45–315 mm |
| Bore position in 23900-series (smallest first) | 2 of 38 |
| Bore above smallest 23900-series size | 10 mm |
Cross references & equivalents
| Equivalent model | Brand | Match level | Note |
|---|---|---|---|
| 23934EMKD1 | NTN | partial Main dimensions match; tolerances, seals or internal clearance differ. | Same NTN 23900-series envelope, cage and ratings; this is the cylindrical-bore execution of the tapered-bore 23934EMKD1 (K/K30 sleeve or tapered-seat mounting). Verify shaft arrangement. |
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 23934EMD1 model number is decoded
23934EMD1 belongs to the 23900 series of NTN spherical rollers and carries the ＊ ULTAGE new-generation mark in the 2203E table: self-aligning, high radial capacity, moderate axial load in either direction. On the NTN nameplate the suffix cluster after the size reads in order: cage design (EM), bore (cylindrical), lubrication feature (D1); 23934EMD1 is assembled exactly in that order. The sphered outer raceway lets the inner-ring assembly pivot, accommodating shaft deflection and housing misalignment (around 1–2° for this class; use the 2203E value for the exact series) without edge loading the rollers. Equivalent-load planning keeps a radial plus moderate axial combination on 23934EMD1; if the axial component dominates, pair with a thrust bearing rather than running one roller row unloaded. Supply grease through the D1 feature during commissioning and at the calculated interval, rotating the 170 mm bore assembly by hand to distribute it across both rows.
Typical equipment & failure modes
Common applications
- large wind-turbine main-shaft arrangements
- steel-mill and heavy crusher main shafts
- mining shovel and dragline swing shafts
- cement-rotary-kiln support and trunnion rolls
Known failure patterns
- raceway spalling at the roller ends when misalignment or deflection concentrates the line contact
- cage damage when a mounting force is applied through the roller set instead of the ring face
- roller-end smearing during skidding starts under light load and high viscosity grease
- rolling-contact fatigue after the catalogue L10 life at the actual load
- fretting corrosion between adapter sleeve and tapered bore when the drive-up is insufficient
Selection pitfalls — read before you substitute
- At 170 mm bore 23934EMD1 is normally mounted on adapter/withdrawal sleeves with hydraulic assistance; follow the NTN drive-up angle or oil-injection procedure — manual nut tightening cannot set the multi-tonne seating correctly.
- Self-aligning does not mean unlimited misalignment: beyond the catalogue angle the outer ring's spherical travel is exhausted and the 468 kN rating no longer applies.
- Adapter-sleeve mounting requires the correct sleeve series and locknut for the 170 mm shaft; a sleeve sized to bore alone ignores thread, width and the oil-injection option on large K seats.
- The two roller rows must share load equally — a tilted spacer or unequal abutment on the 45 mm-wide ring loads one row only and shows as asymmetric race polish during inspection.
- Minimum load must be maintained even at rest under vibration: an unloaded 23934EMD1 on a stopped screen false-brinells; parking brakes and shaker isolation both matter.
- The 468/723 kN ratings, 48.8 kN Pu and 5390 g mass are NTN Ball and Roller Bearings CAT.No.2203E values for 23934EMD1 (EM machined-brass-cage/D1); another maker's same-envelope part revises internal geometry, so re-verify ratings and cage before substitution on vibrating or rated drives.
Frequently asked questions
What are the dimensions and catalogue data of 23934EMD1?
23934EMD1 is an NTN double-row spherical roller bearing to ISO 15: 170 mm bore, 230 mm OD and 45 mm width (6.693 × 9.055 × 1.772 in). From NTN Ball and Roller Bearings CAT.No.2203E: C 468 kN, C0 723 kN, Pu 48.8 kN, grease limiting speed 1,800 r/min, oil 2,300 r/min, mass about 5390 g. It is open, with one-piece machined brass cage (EM high-capacity design).
What is the difference between the K/K30 tapered bore and the cylindrical bore versions?
23934EMD1 has a cylindrical bore and mounts directly on a machined shaft seat. Its tapered-bore counterpart is 23934EMKD1 (K = 1:12, or K30 = 1:30 on the wide series), intended for adapter/withdrawal-sleeve mounting.
What do EA and EM mean on NTN spherical roller bearings?
EA is the NTN standard-capacity/high-capacity execution with a pressed sheet-steel window cage; EM is the high-capacity execution with a one-piece machined brass cage. Both use the optimised symmetric-roller design, but cage identity changes mass, speed behaviour and suitability for duties like vibrating screens, so they are separate order numbers. 23934EMD1 is the EM machined-brass-cage execution, listed with the ＊ ULTAGE new-generation mark.
What do D1 and W33 mean on 23934EMD1?
D1 is NTN's outer-ring lubrication feature: an annular groove with oil holes around the outer ring, aligned with a housing grease port so lubricant reaches both roller rows directly. 23934EMD1 carries D1; W33 is the equivalent industry-spelled annular-groove-and-holes feature seen on other executions.
How much misalignment and axial load can 23934EMD1 take?
The sphered outer raceway compensates static and dynamic misalignment in the order of 1–2° (verify the exact 2203E figure for the 23900 series); beyond that, load concentrates on one roller row. Load is predominantly radial with a moderate axial share in either direction — 468 kN C / 723 kN C0 — but sustained pure axial load is not recommended because it unloads one row.
Reviewed & verified by the MPN Base engineering desk against source catalog NTN Ball and Roller Bearings CAT.No.2203E on 2026-10-01. Read our editorial & correction policy.