NSK7204CTYDULPA7Super Precision Angular Contact Ball Bearing Pair 20x47x14 mm, 15° Contact Angle, Light Preload

Product Description

What this part is

A matched pair of super-precision angular contact ball bearings in the 20 mm bore × 47 mm outside diameter × 14 mm width envelope, the ISO 7204 size. Single row each, universally ground so the pair reaches its specified preload when clamped solid.

Decoding the designation

In the NSK super-precision scheme C is a 15° contact angle, distinct from A at 30° and A5 at 25°, so a 7204C and a 7204A5 are different bearings sharing one envelope. DUL is duplex universal with light preload. PA7 is the NSK class marking carried on the carton. The 7204 itself places the bearing in ISO dimension series 72 at a 20 mm bore.

What these specs mean in practice

A 15° contact angle carries more radial load and runs faster than a 25° or 30° bearing of the same size, and carries correspondingly less thrust. Light preload removes internal play and fixes the contact angle while adding the least heat of the three preload grades, which keeps axial position and runout repeatable without penalising speed. Duplex grinding turns the class tolerances into the preload itself: the ring faces are relieved by a measured amount, so clamping the pair solid produces the light preload directly with no shimming.

Thrust direction

Each bearing carries radial load together with thrust in one direction only. Mounted back-to-back or face-to-face the pair locates the shaft axially in both directions, one row acting in each; mounted in tandem both act in the same direction at roughly doubled capacity.

Quantity and configuration

2 Pcs. One universally ground pair, 28 mm total width when clamped solid, supplied without spacers, locknut or housing.

Fitting notes

Universal grinding means the two rings stack back-to-back, face-to-face or in tandem and arrive at the specified light preload with no shimming or hand grinding. The pair is assembled in the orientation its face marks indicate and the inner rings are clamped solid against one another so the ground relief sets the preload. Seats at this class are ground and measured, and the preload is only realised when both outer rings seat fully in the housing bore.

Interchange guidance

NSK acquired RHP and continued its numbering, so the RHP form 7204CTDULP4 is the direct counterpart designation. The Fafnir-scheme equivalent is Timken 2MM204WI CR DUL, the 2MM prefix likewise denoting 15°. A 7204 in this envelope at 25° or 30°, or at a medium or heavy preload grade, is a related size rather than a substitution.