Manufactured by CHG Bearing, the NNU 4956 BK/SPW33 is a precision Super-Precision Cylindrical Roller Bearings. Key dimensional parameters include a 280 mm bore diameter, a 380 mm outer diameter, and a 100 mm overall width. This component is designed to meet standard load requirements and ensure consistent operational performance. For comprehensive technical evaluation, please explore the detailed specifications, dimensional data, product images, and CAD drawings provided below. A complete PDF data sheet is also readily available for direct download to support your engineering and procurement needs.
NNU 4956 BK/SPW33 - Super-Precision Cylindrical Roller Bearings
Technical Specifications
| Overview | |
|---|---|
| Part Number | NNU 4956 BK/SPW33 |
| Brand | CHG® |
| Characteristics | |
| Bearing Type | Super-precision Cylindrical Roller Bearing |
| Design Type | Tapered Bore 1:12 |
| Structure (Drawing Reference) | Complete Bearing |
| Number of Rows | 2 |
| Ring Type | None |
| Design | NNU Design |
| Tolerance Class | SP |
| Bearing Material | Bearing Steel |
| Coating | None |
| Sealing | None |
| Lubricant | None |
| Features | Annular Lubrication Groove and Lubrication Holes |
| Number of Flanges – Outer Ring | 3 |
| Number of Ribs – Inner Ring | 0 |
| Dimensions | |
| Bore Diameter (d) | 280 mm |
| Width (B) | 100 mm |
| Outer Diameter (D) | 380 mm |
| Minimum Chamfer Dimension rmin | 2 mm |
| Inner Ring Chamfer | 2.1 mm |
| Outer Ring Chamfer | 1.1 mm |
| End-face Height Difference h | 4.5 mm |
| Outer-Ring Land Diameter (L2 / D1) | 345.6 mm |
| Inner Ring Raceway Diameter F | 312 mm |
| Shaft Shoulder Diameter dₐ, min. | 291 mm |
| Shaft Shoulder Diameter dₐ, max. – NNU Design | 308 mm |
| Housing Shoulder Diameter Dₐ, max. | 369 mm |
| Performance | |
| Basic Dynamic Load Rating C (kN) | 765 kN |
| Basic Static Load Rating C₀ (kN) | 1800 kN |
| Limiting Speed – Grease (r/min) | 1900 r/min |
| Limiting Speed – Oil-air (r/min) | 2200 r/min |
| Reference Grease Quantity Gref (cm³) | 384 cm³ |
| Fatigue Load Limit Pᵤ (kN) | 170 kN |
| Axial Static Stiffness – Guideline Value (N/µm) | 7260 N/µm |
| Material | |
| Lubrication Groove Width | 13.9 mm |
| Lubrication Holes (qty × Ø mm) | 3 |
| Weight (kg) | 32.1 kg |
| Radial Internal Clearance | C1 mm |
| Internal Design & Weight | |
| Cage Type | Machined Metal Cage |
| Mounting Dimensions | |
| Lubrication Port Thread / Size Φ1 | 313.5 |
NNU 4956 BK/SPW33 380 mm 280 mm 100 mm Frequently Asked Questions about NNU 4956 BK/SPW33 Super-Precision Cylindrical Roller Bearings
Find key technical answers regarding dimensions, specifications, and replacement options for this model.
When fitting NNU 4956 BK/SPW33 over a 280 mm shaft, CHG Bearing strictly recommends uniform induction heating (controlled between 90°C and 110°C) or precision hydraulic press sleeves. Under no circumstances should direct impact blows be struck against the rings or cage, as shock loads cause brinelling indents and premature spalling.
Model NNU 4956 BK/SPW33 is manufactured by CHG Bearing in standard Normal clearance (CN) for ambient temperature transmission, and C3 or C4 clearance for heavy duty applications. C3 clearance compensates for radial shrinkage caused by tight shaft press-fits (bore 280 mm) and steep thermal gradients between inner and outer rings.
Built for demanding industrial environments, the NNU 4956 BK/SPW33 Super-Precision Cylindrical Roller Bearings by CHG Bearing boasts a dynamic load rating (Cr) of standard dynamic and a static load threshold (C0r) of standard static. The optimized internal raceway geometry balances stress distribution, mitigating edge loading even when operating under peak mechanical stresses.
Beyond standard alloy steel, CHG Bearing can customize the NNU 4956 BK/SPW33 Super-Precision Cylindrical Roller Bearings using AISI 440C stainless steel, black oxide coating, zinc-nickel plating, or hybrid ceramic (Si3N4) balls for applications involving chemical exposure, marine salt fog, or galvanic current hazards.
