Manufactured by CHG Bearing, the NNU 4938 B/SPW33 is a precision Super-Precision Cylindrical Roller Bearings. Key dimensional parameters include a 190 mm bore diameter, a 260 mm outer diameter, and a 69 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 4938 B/SPW33 - Super-Precision Cylindrical Roller Bearings
Technical Specifications
| Overview | |
|---|---|
| Part Number | NNU 4938 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) | 190 mm |
| Width (B) | 69 mm |
| Outer Diameter (D) | 260 mm |
| Minimum Chamfer Dimension rmin | 2 mm |
| Inner Ring Chamfer | 2 mm |
| Outer Ring Chamfer | 2 mm |
| End-face Height Difference h | 1.1 mm |
| Outer-Ring Land Diameter (L2 / D1) | 236 mm |
| Inner Ring Raceway Diameter F | 212 mm |
| Shaft Shoulder Diameter dₐ, min. | 200 mm |
| Shaft Shoulder Diameter dₐ, max. – NNU Design | 209 mm |
| Shaft Shoulder Diameter dᵦ, min. – NNU Design | 215 mm |
| Housing Shoulder Diameter Dₐ, max. | 250 mm |
| Performance | |
| Basic Dynamic Load Rating C (kN) | 402 kN |
| Basic Static Load Rating C₀ (kN) | 880 kN |
| Limiting Speed – Grease (r/min) | 2800 r/min |
| Limiting Speed – Oil-air (r/min) | 3200 r/min |
| Reference Grease Quantity Gref (cm³) | 85 cm³ |
| Fatigue Load Limit Pᵤ (kN) | 90 kN |
| Axial Static Stiffness – Guideline Value (N/µm) | 5380 N/µm |
| Material | |
| Lubrication Groove Width | 8.3 mm |
| Lubrication Holes (qty × Ø mm) | 3 |
| Weight (kg) | 11.2 kg |
| Radial Internal Clearance | C1 mm |
| Internal Design & Weight | |
| Cage Type | Machined Metal Cage |
| Mounting Dimensions | |
| Lubrication Port Thread / Size Φ1 | 213 |
NNU 4938 B/SPW33 260 mm 190 mm 69 mm Frequently Asked Questions about NNU 4938 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 4938 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.
Model NNU 4938 B/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 190 mm) and steep thermal gradients between inner and outer rings.
Every production batch of CHG Bearing NNU 4938 B/SPW33 Super-Precision Cylindrical Roller Bearings comes with complete traceability. Upon shipment, CHG Bearing can provide EN 10204 3.1 Material Test Reports (MTR), Certificates of Conformity (CoC), spectral chemical composition analysis, and dimensional inspection sheets.
Standard batches of CHG Bearing NNU 4938 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.
