Manufactured by CHG Bearing, the NNU 4944 B/SPW33 is a precision Super-Precision Cylindrical Roller Bearings. Key dimensional parameters include a 220 mm bore diameter, a 300 mm outer diameter, and a 80 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 4944 B/SPW33 - Super-Precision Cylindrical Roller Bearings
Technical Specifications
| Overview | |
|---|---|
| Part Number | NNU 4944 B/SPW33 |
| Brand | CHG® |
| Characteristics | |
| Bearing Type | Super-precision Cylindrical Roller Bearing |
| Design Type | Cylindrical Bore |
| 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) | 220 mm |
| Width (B) | 80 mm |
| Outer Diameter (D) | 300 mm |
| Minimum Chamfer Dimension rmin | 2 mm |
| Inner Ring Chamfer | 2.1 mm |
| Outer Ring Chamfer | 2.1 mm |
| End-face Height Difference h | 3.7 mm |
| Outer-Ring Land Diameter (L2 / D1) | 272.2 mm |
| Inner Ring Raceway Diameter F | 245 mm |
| Shaft Shoulder Diameter dₐ, min. | 231 mm |
| Shaft Shoulder Diameter dₐ, max. – NNU Design | 242 mm |
| Shaft Shoulder Diameter dᵦ, min. – NNU Design | 249 mm |
| Housing Shoulder Diameter Dₐ, max. | 289 mm |
| Performance | |
| Basic Dynamic Load Rating C (kN) | 512 kN |
| Basic Static Load Rating C₀ (kN) | 1140 kN |
| Limiting Speed – Grease (r/min) | 2400 r/min |
| Limiting Speed – Oil-air (r/min) | 2800 r/min |
| Reference Grease Quantity Gref (cm³) | 150 cm³ |
| Fatigue Load Limit Pᵤ (kN) | 114 kN |
| Axial Static Stiffness – Guideline Value (N/µm) | 5990 N/µm |
| Material | |
| Lubrication Groove Width | 11.1 mm |
| Lubrication Holes (qty × Ø mm) | 3 |
| Weight (kg) | 16.5 kg |
| Radial Internal Clearance | C1 mm |
| Internal Design & Weight | |
| Cage Type | Machined Metal Cage |
| Mounting Dimensions | |
| Lubrication Port Thread / Size Φ1 | 247 |
NNU 4944 B/SPW33 300 mm 220 mm 80 mm Frequently Asked Questions about NNU 4944 B/SPW33 Super-Precision Cylindrical Roller Bearings
Find key technical answers regarding dimensions, specifications, and replacement options for this model.
Yes, 100% of NNU 4944 B/SPW33 Super-Precision Cylindrical Roller Bearings leaving CHG Bearing production lines are subjected to multi-frequency Anderometer sound testing. All units satisfy baseline Z1V1 levels, with dedicated quiet-running electric motor quality (EMQ) lots certified to Z2V2 and Z3V3 standards for silent machinery integration.
Standard batches of CHG Bearing NNU 4944 B/SPW33 conform strictly to ISO Class Normal (ABEC-1). For high-precision machine tool spindles, gearboxes, or robotics requiring tighter runouts, CHG Bearing can provide custom batches graded to ISO Class 6 (P6/ABEC-3) or ISO Class 5 (P5/ABEC-5) with 100% micrometer verification.
Quality starts with raw material selection: CHG Bearing crafts NNU 4944 B/SPW33 inner and outer rings from high-purity High-Quality Chrome Steel (GCr15/100Cr6). Our raw billets undergo vacuum degassing and secondary ESR (electroslag remelting) processes to drastically eliminate non-metallic sulfide and oxide inclusions, elevating subsurface contact fatigue resistance.
To safeguard CHG Bearing NNU 4944 B/SPW33 against fretting wear and false brinelling during transport or vibration, assemble mating surfaces (220 mm x 300 mm) using anti-fretting mounting paste. Maintaining strict alignment and avoiding prolonged static vibration will preserve raceway polish.
