Timken24720DDouble Tapered Roller Bearing Cup, 3 in. Outside Diameter, 1.5625 in. Width, Two-Row TDO Imperial Inch Series

Product Description

What this part is:

A double tapered roller bearing cup in the 24720D size — a one-piece outer ring carrying two opposed tapered raceways, the outer half of a two-row TDO (tapered double outer) bearing. Cup only. It is mated with two cones; the published cone is the Timken 24780, used one per row.

Decoding the designation:

24720 is the inch-series cup number and the D suffix marks it as a double cup rather than a single. That distinction is dimensional as well as descriptive: the single 24720 cup is 0.875 in. wide, while the 24720D is 1.5625 in. wide because it holds two raceways in one ring. The alternate written form is 24720-D. Cup numbers in the 247xx block pair with cone numbers in the same block, which is why the mating cone is a 24780.

What these specs mean in practice:

A TDO arrangement puts both rows inside a single outer ring, so the bearing takes thrust in both directions and carries an overturning moment on a short mounting length. Because the two raceways are ground in one piece, their spacing and angle relationship is fixed at manufacture and the row-to-row setting is controlled by the cup rather than by shimming the housing — the practical advantage over two single-row bearings mounted back to back. The load lines diverge outward from the cup centre, which gives a wide effective bearing spread inside a compact envelope. That suits wheel hubs, idler rolls, sheaves and pinion positions where the housing bore is short and both axial directions are loaded.

Published dimensions and assembly data:

• Double cup outside diameter: 3.0000 in. (76.2 mm)
• Double cup width: 1.5625 in. (39.688 mm)
• Number of raceways in the cup: 2, one-piece outer ring
• Mating cone 24780: bore 1.6250 in. (41.275 mm), cone width 0.906 in.
• Complete 24780–24720D TDO assembly: 41.275 mm bore × 76.2 mm outside diameter × 49.21 mm overall width (T = 1.9375 in.)
• Dynamic radial rating of the complete 24780–24720D TDO assembly: 132 kN

Quantity and configuration:

One double cup, sold individually. Two rows, straight outside diameter, no flange.

Fitting notes:

The double cup presses into the housing bore and is driven on the backface with a flat tool contacting the whole ring. A TDO build normally seats the cup first and then enters a cone from each end, with the assembly clamped on the shaft; the housing bore takes the cup as a light press and the cup usually needs no shoulder on both sides because the two rows locate each other.

Interchange guidance:

The plain 24720 single cup is a different part: it is 0.875 in. wide with one raceway and belongs to a single-row TS bearing. The 24720D also pairs with the NA24776SW cone in a published TDO assembly.