Sprocket 28B-3 (1 3/4") z=20 with hub, steel

Product Description

Sprocket 28B-3 (1 3/4") z=20 with hub, steel works with 28B-3 roller chain (European standard DIN 8187 / ISO 606), triple-strand (triplex), with a pitch of 44.45 mm (1 3/4"). It has 20 teeth and is made of structural steel.

The sprocket has a one-sided hub with a diameter of 180 mm, welded to the plate, and a pilot bore of Ø30 mm, which is bored to the shaft size and completed with a keyway or a set screw hole. The total width of the sprocket is 180 mm.

Technical data

Applications

It is used in sawmills, cement plants and bulk material handling lines. The triple-strand version is chosen for very heavily loaded drives where there is no room for a chain with a larger pitch.

Frequently asked questions

Which chain does the 28B-3 z=20 sprocket fit?

28B-3 roller chain to European standard DIN 8187 / ISO 606, with a pitch of 44.45 mm. A triplex sprocket requires a triple-strand (triplex) chain.

Does it fit ASA 140 chain?

No. ASA 140 chain (American standard) has the same pitch, but a different roller diameter (25.4 mm instead of 27.94 mm) and a different inner width (25.4 mm instead of 30.99 mm). The 28B sprocket is designed for European-standard chain, so the two systems should not be mixed.

How does the number of teeth affect the drive ratio?

The ratio is the number of teeth of the driven wheel divided by the number of teeth of the driving wheel. If this sprocket drives a wheel with twice as many teeth, the driven shaft turns twice as slowly but with roughly twice the torque.

Why does the sprocket have a pilot bore and how is it machined?

The pilot bore Ø30 mm is left on purpose so that it can be bored precisely to the machine shaft size. The sprocket is clamped in a lathe by the outer edge of the hub to avoid run-out, and the bore is usually machined to H7 tolerance. The maximum bore diameter depends on the hub diameter.

How is a keyway cut in the hub?

The keyway is made to DIN 6885, keeping it aligned and with the correct width and depth so that the key sits firmly. The key should fit accurately - play in the keyway accelerates wear and, under shock loads, can lead to the key shearing off.

What does the lead time depend on?

When ordering, please check the current stock level of this sprocket - the lead time depends on it and is clearly stated according to the quantity available in each warehouse. The stock level is shown above the product price and may vary depending on the warehouse.

Product photos are for illustration purposes only.