Koyo7224BGP5FYAngular Contact Ball Bearing 120x215x40 mm, 40° Contact Angle, P5 Precision Class, Machined Brass Cage, Open

Product Description

What this part is

A single-row angular contact ball bearing in the 7224 envelope — 120 mm bore, 215 mm outside diameter, 40 mm width. Open type, 40° contact angle, machined brass cage, held to ISO precision class 5. Koyo is the bearing brand of JTEKT.

Decoding the designation

7224 — ISO 72 dimension series, bore code 24, giving a 120 mm bore. The 120 x 215 x 40 mm envelope agrees with the recorded dimensions.
B — in Koyo’s scheme, a 40° contact angle. This is the critical letter on the part.
G — machined brass (high-tensile brass) cage.
P5 — ISO precision class 5, a step tighter than standard P0 but not as fine as the P4/ABEC 7 spindle grades.
FY — Koyo internal variant marking; no published decode was located, so it is retained as a search term rather than translated into a spec.

What these specs mean in practice

A 40° contact angle is at the far thrust-biased end of the angular contact range. It carries a great deal more axial load than the 15° and 25° spindle grades, and holds axial position very firmly, but it runs slower and hotter and carries proportionally less pure radial load. That makes it the right choice for positions dominated by thrust — vertical shafts, worm and bevel pinion positions, screw-down and thrust-taking assemblies — and the wrong choice for a high-speed spindle.

This is the point to be careful about with the 7224 envelope. A 15° (7224C) and a 40° (7224B) bearing are dimensionally identical: same bore, same outside diameter, same width, same box shape. They are not remotely interchangeable in function. If you are replacing an existing bearing, read the suffix on the old one rather than measuring it.

The machined brass cage is worth having: it is stronger than a pressed steel cage under shock and acceleration, tolerates higher temperatures, and is standard on larger and more heavily loaded angular contact bearings. P5 class controls running accuracy to closer limits than standard, which matters where the bearing sets a shaft position or where vibration is a concern.

Published ratings and mounting data

Basic dynamic and static load ratings and limiting speed are deliberately blank. We could not retrieve Koyo’s own published figures for this exact designation, and we have declined to substitute figures from another maker’s 7224B or from a 7224C in the same envelope — a different contact angle produces different ratings. Contact Koyo/JTEKT or an authorised distributor with the full designation if a certified rating is required.

Quantity and configuration

One bearing. The designation carries no duplex or universal-grinding code, so this is a plain single rather than half of a matched preloaded set. Bear in mind that a single angular contact bearing takes thrust in one direction only and must be opposed within the assembly.

Fitting notes

Observe the thrust-direction marking on the outer ring — a 40° bearing fitted backwards puts the entire thrust load onto the unsupported shoulder and will fail rapidly. Press only on the ring being fitted, never through the balls. Confirm the shaft and housing are machined to a tolerance consistent with P5.

Interchange guidance

ISO base number 7224. Contact-angle suffixes vary by maker, and the letter B is particularly inconsistent across brands, so always confirm the angle rather than the letter. We also hold an NDH bearing in this identical 120 x 215 x 40 mm envelope, but at a shallower contact angle and in a duplex tandem arrangement — if you are matching an existing installation, tell us the suffix on the bearing you are replacing and we will point you at the right one.