NSK7009A5TRSULP4YSuper Precision Angular Contact Ball Bearing 45x75x16 mm 25° Light Preload Phenolic Cage

Product Description

What this part is

A single-row super-precision angular contact ball bearing, 45 mm bore, 75 mm outside diameter, 16 mm width. It is universally ground to a light preload band, so it can be stacked with further pieces of the same designation in any orientation, and it carries a 25° contact angle with a phenolic laminate cage guided on the outer ring.

Decoding the designation

The 70 prefix and bore code 09 give ISO dimension series 70 at a 45 mm bore. In the NSK scheme A5 is a 25° contact angle — distinct from A at 30° and C at 15°. TR is a machined phenolic laminate cage guided on the outer ring land, rated to a 120 °C ceiling. SU is a universally ground single, L the light preload grade, and P4Y an NSK special tolerance class held tighter than standard P4. The alternate number 7009E on the carton uses the RHP and Timken angle letter E, also 25°, which confirms the angle from a second designation.

What these specs mean in practice

A 25° contact angle is the thrust-biased option in this envelope. Axial capacity and axial stiffness both climb with contact angle, so a 25° bearing holds spindle position harder against cutting thrust than a 15° bearing of the same size. The price is speed: the steeper load line increases ball centrifugal and gyroscopic effects, giving a lower speed limit and more heat at equal duty.

A phenolic cage guided on the outer ring land is the high-speed cage choice. Phenolic is light, so cage inertia and ball-pocket loads stay low, and it holds an oil film well; the outer-land guidance keeps the cage stable and running true at speed instead of letting it wander on the balls. The 120 °C ceiling is the limit that matters, since phenolic is the temperature-limiting element rather than the steel.

P4Y is tighter than the ABEC 7 baseline, which is what makes this piece usable where bore and ring runout drive the workpiece finish directly. Light preload adds the least friction heat of the preload grades, so it suits fast, moderately loaded spindles and grinding heads.

Quantity and configuration

1 Pc. Universally ground single (SU), suppliable and usable on its own or stacked with matching pieces.

Thrust direction

A single-row angular contact ball bearing carries thrust in one direction only. Axial load in the opposite direction is taken by a second bearing opposing this one, or by another element in the shaft stack.

Fitting notes

Universal grinding means any two pieces of this designation clamp solid to produce the light preload directly, in back-to-back, face-to-face or tandem orientation, with no shimming. Shaft and housing seats at this class are ground and measured, typically j4 to k4 on the shaft and H5 to J5 in the housing. Mounting orientation follows the face marks, with the thrust face taking the load.

Interchange guidance

7009E is the same bearing under the RHP and Timken angle scheme. Same-envelope bearings differing in contact angle, preload grade, cage or tolerance class — 7009C at 15°, 7009A at 30°, the TYN polyamide-caged version, medium and heavy preload grades, and standard P4 or P5 class pieces — are related sizes rather than interchanges. A duplex-ground DU piece of the same size is a different item, since DU faces are relieved for a specific pair stack height.