Manufactured by CHG Bearing, the NNU 4948 B/SPW33 is a precision Super-Precision Cylindrical Roller Bearings. Key dimensional parameters include a 240 mm bore diameter, a 320 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 4948 B/SPW33 - Super-Precision Cylindrical Roller Bearings
Technical Specifications
| Overview | |
|---|---|
| Part Number | NNU 4948 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) | 240 mm |
| Width (B) | 80 mm |
| Outer Diameter (D) | 320 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) | 292.2 mm |
| Inner Ring Raceway Diameter F | 265 mm |
| Shaft Shoulder Diameter dₐ, min. | 251 mm |
| Shaft Shoulder Diameter dₐ, max. – NNU Design | 262 mm |
| Shaft Shoulder Diameter dᵦ, min. – NNU Design | 269 mm |
| Housing Shoulder Diameter Dₐ, max. | 309 mm |
| Performance | |
| Basic Dynamic Load Rating C (kN) | 528 kN |
| Basic Static Load Rating C₀ (kN) | 1220 kN |
| Limiting Speed – Grease (r/min) | 2200 r/min |
| Limiting Speed – Oil-air (r/min) | 2600 r/min |
| Reference Grease Quantity Gref (cm³) | 171 cm³ |
| Fatigue Load Limit Pᵤ (kN) | 118 kN |
| Axial Static Stiffness – Guideline Value (N/µm) | 6340 N/µm |
| Material | |
| Lubrication Groove Width | 11.1 mm |
| Lubrication Holes (qty × Ø mm) | 3 |
| Weight (kg) | 18.3 kg |
| Radial Internal Clearance | C1 mm |
| Internal Design & Weight | |
| Cage Type | Machined Metal Cage |
| Mounting Dimensions | |
| Lubrication Port Thread / Size Φ1 | 267 |
NNU 4948 B/SPW33 320 mm 240 mm 80 mm Frequently Asked Questions about NNU 4948 B/SPW33 Super-Precision Cylindrical Roller Bearings
Find key technical answers regarding dimensions, specifications, and replacement options for this model.
To match diverse operational dynamics, CHG Bearing supplies NNU 4948 B/SPW33 with multiple cage configurations: high-strength pressed steel ribbon cages for standard duty, solid machined brass cages (M/CA) for heavy vibration and shock loads, or lightweight glass-fiber reinforced polyamide cages (TN9/TVP) for high acceleration and ultra-low noise.
Yes, CHG Bearing works closely with industrial OEMs and brand distributors. We offer turnkey custom engineering for NNU 4948 B/SPW33, including laser-etched customer logos, custom internal radial clearances, specialized grease formulations, and bespoke protective packaging.
As standard production, CHG Bearing subjects NNU 4948 B/SPW33 to precision bainite or martensite quenching, offering dimensional stability up to 120°C (248°F). For high-heat processing equipment, CHG Bearing also supplies custom S0 (150°C), S1 (200°C), or S2 (250°C) stabilization heat treatments upon request to prevent residual austenite transformation.
Engineered according to international ISO boundary plans, CHG Bearing supplies NNU 4948 B/SPW33 with a precision bore diameter (d) of 240 mm, an outside diameter (D) of 320 mm, and a nominal ring width (B) of 80 mm. This configuration yields an effective cross-sectional wall thickness of 40.0 mm and an envelope ratio (D/d) of 1.33, delivering compact rigidity for OEM machinery housings.
