NSK 638VV dimensions and catalogue data
NSK 638VV is a listed metric-series single-row deep groove ball bearing. The published dimensions are 8×28×9 mm, using bore d, outside diameter D and closed width B1.
Non-contact rubber seals on both sides (VV). Dynamic radial rating Cr: 5.05 kN; static radial rating C0r: 1.97 kN.
How to use this model record
- This is an independently organised catalogue reference, not an installation drawing or approval for a machine or vehicle.
- Compare the complete designation. B and B1 may differ between open and closed versions; a related base number does not establish the same width.
- Load ratings are calculation inputs, not universal permissible loads. Limiting speed depends on the stated closure, lubrication and application conditions.
- Shaft-shoulder and housing-shoulder values describe adjacent mounting geometry. Preserve the min./max. direction; they are not alternative bearing diameters.
- Precision class, radial internal clearance, grease specification, material grade and fitment are not established by this table. Missing values are not zero.
- A rotating outer ring requires a manufacturer application check for shielded or sealed constructions.
- The source gives separate open and shielded masses, not the mass of this sealed version; no mass is inferred for it.
Technical basis:NSK Rolling Bearings for Industrial Machinery, E1103d (2025), Part C, C060–C061; source checked 2026-10-01. Manufacturer facts are reorganised for model lookup and comparison; no manufacturer document is republished.
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Technical data
Product specifications
Metric and imperial values are paired where the manufacturer provides both. Expand a section to review its parameters.
Core specifications7 parameters
| Parameter | Symbol | Value |
|---|---|---|
| Variant / construction | Single row deep groove ball bearings | |
| Bore diameter | d | 8 mm |
| Outside diameter | D | 28 mm |
| Width | B | 9 mm |
| Basic dynamic load rating | C | 5.05 kN |
| Basic static load rating | C0 | 1.97 kN |
| Sealing | Non-contact rubber seals on both sides (VV) |
Mounting dimensions3 parameters
| Parameter | Symbol | Value |
|---|---|---|
| Maximum shaft shoulder diameter (closed) | db max. | 12.8 mm |
| Maximum adjacent fillet radius | rb max. | 0.3 mm |
| Minimum housing shoulder diameter (closed) | Db min. | 22.8 mm |
Boundary dimensions4 parameters
| Parameter | Symbol | Value |
|---|---|---|
| Bore diameter | d | 8 mm |
| Outside diameter | D | 28 mm |
| Bearing width (closed) | B1 | 9 mm |
| Minimum bearing chamfer | r1 min. | 0.3 mm |
Construction1 parameter
| Parameter | Symbol | Value |
|---|---|---|
| Catalogue closure construction | Non-contact rubber seals on both sides (VV) |
Load ratings2 parameters
| Parameter | Symbol | Value |
|---|---|---|
| Basic dynamic radial load rating | Cr | 5050 N |
| Basic static radial load rating | C0r | 1970 N |
Lubrication-qualified speed1 parameter
| Parameter | Symbol | Value |
|---|---|---|
| Limiting speed with grease | 28000 r/min |