NSK 7328ADB dimensions and technical reference
NSK 7328ADB is a angular contact matched pair reference with nominal assembled dimensions 140×300×124 mm. The order is bore d × outside diameter D × total pair width 2B. Use the full marking and construction, not only the base number, when comparing candidates.
Contact angle, cage and complete marking
The catalogue base 7328A uses a 30° nominal contact angle (A). Its standard machined-brass cage is shown as (M), which is normally omitted from the designation. The ratings below belong to this standard cage; optional cage codes are not extra products with automatically identical performance.
How this matched arrangement works
Carries radial loads and axial loads in both directions. Its separated effective load centres support moment loading; this is not a numerical moment-capacity rating. Each constituent bearing has width B = 62 mm; the catalogue diagram specifies a two-bearing width of 2B = 124 mm. Pair ratings are read directly from the matched columns, not calculated by doubling the single dynamic rating.
Arrangement-specific load calculation
For Fr > 0 and Fa/Fr ≤ 0.80, P = Fr + 0.78Fa. Above that ratio, P = 0.63Fr + 1.24Fa. Static equivalent load is P0 = Fr + 0.66Fa. Fr and Fa are the applicable radial and axial loads in consistent units. Resolve reactions and load sharing for the actual bearing arrangement before using the formula; the factors alone do not establish safe machine loads.
Reading speed and lubrication data
The source gives a grease limiting speed of 1600 r/min. The oil limiting speed is 2000 r/min. These values are for the matched arrangement, not every cage or closure sharing the same dimensions. Near the limit, assess load, lubricant, temperature and heat removal; a catalogue speed is not a guaranteed continuous-duty speed.
Selection and mounting limits
- DB, DF and DT identify different matching arrangements, not user-created sets made safe merely by placing two loose bearings together. Verify the supplied set and clearance/preload specification.
- The catalogue omission rule refers to CN clearance for ordinary matched designations; it does not supply a numerical installed clearance, preload force or nut torque for this assembly.
- For a dash in the db column, NSK directs use of da minimum and ra maximum. The substitute applies to that mounting note, not to missing load or speed values. Follow the relevant single, DB or DF drawing; a DT shoulder layout is not fully specified here.
- The mass field belongs to one bearing. It has not been relabelled as a measured matched-pair mass.
- A rating is a calculation reference, not an allowable load for an unspecified machine. Lubrication, fit, temperature, alignment and operating load still matter.
- This source does not establish machine fitment, replacement approval, a CAD file, friction torque or an installed preload. Missing values remain unstated rather than being copied from a similar model.
Technical basis:NSK Rolling Bearings for Industrial Machinery, E1103d (2025), Part C, C102–C103; construction and identification rules C072–C077. Source checked 2026-10-01. Independently organised technical reference, not a sales offer or interchange approval.
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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 | Angular contact ball bearing | |
| Bore diameter | d | 140 mm |
| Outside diameter | D | 300 mm |
| Width | B | 124 mm |
| Basic dynamic load rating | C | 540 kN |
| Basic static load rating | C0 | 670 kN |
| Cage | Machined brass, inner-ring guided |
Boundary dimensions6 parameters
| Parameter | Symbol | Value |
|---|---|---|
| Bore diameter | d | 140 mm |
| Outside diameter | D | 300 mm |
| Individual bearing width | B | 62 mm |
| Minimum bearing chamfer | r min. | 4 mm |
| Nominal width of two-bearing assembly | 2B | 124 mm |
| Minimum secondary bearing chamfer | r1 min. | 1.5 mm |
Construction6 parameters
| Parameter | Symbol | Value |
|---|---|---|
| Nominal contact angle | α | 30 ° |
| Standard cage code | M usually omitted | |
| Optional cage codes — ratings require separate confirmation | T | |
| Catalogue matching scope | DB, DF, DT | |
| Cage material and construction | Machined brass, inner-ring guided | |
| Construction / arrangement | Back-to-back matched pair |
Load-centre geometry2 parameters
| Parameter | Symbol | Value |
|---|---|---|
| Single-bearing effective load centre | a | 94.5 mm |
| Matched-pair load-centre spacing | a0 (DB) | 189 mm |
Lubrication-qualified speed2 parameters
| Parameter | Symbol | Value |
|---|---|---|
| Limiting speed — grease | 1600 r/min | |
| Limiting speed — oil | 2000 r/min |
Mass reference1 parameter
| Parameter | Symbol | Value |
|---|---|---|
| Single-bearing approximate mass (not pair mass) | 21.4 kg |
Matched-pair load ratings2 parameters
| Parameter | Symbol | Value |
|---|---|---|
| Basic dynamic radial load rating | Cr | 540000 N |
| Basic static radial load rating | C0r | 670000 N |
Mounting dimensions — shown arrangement3 parameters
| Parameter | Symbol | Value |
|---|---|---|
| Minimum shaft shoulder diameter | da min. | 158 mm |
| Maximum housing shoulder diameter | Db max. | 291 mm |
| Maximum shaft-side fillet radius | ra max. | 3 mm |