Timing Belts and Pulleys

When choosing a timing belt that best suits your needs, there are a few factors to keep in mind.  For example, the environment plays a role in the deterioration of the belt; especially when exposed to extremely high or low temperatures. Excess dust particles and are known to increase the belt tension, which adds excess wear to the belt. When it is time to choose, carefully select the belt material as a surplus of grease or oil will cause the material to tear. Polyurethane belts are the best option for harsh environments. If there is any chance that the belt and pulley system you are selecting will be operating in the presence of ozone gas, either a polyurethane or rubber belts with an ozone block chemical would be your best bet.  Standard rubber will eventually show characteristics of degradation that are similar to high-temperature exposure.

Timing belt and pulley systems can help minimize issues that are common with the traditional chain and sprocket power transmission system. Belt and pulley systems typically require no lubrication and have longer maintenance periods.

Variety of Timing Belts and Pulleys

There are different varieties of timing belts for power transmissions, such as V-belts and flat belts. Friction systems like V-belts and flat belts are a cheaper alternative but unfortunately, have some downsides. The way they are designed and manufactured causes them to operate at a lower efficiency. That, in turn, will generate heat and result in lower power outputs compared to timing, or synchronous belts. Since both belts are friction systems, they require the highest belt tension, which may cause excess loading on the bearing and overhung load on the pulley shafts. The advantages of choosing V-belts, are that they operate with lower noise and are the least expensive belt option on the market. Timing belts and pulleys maintain system timing much better than both flat and V-belts because they have a toothed belt and teeth pulleys or sprockets. The toothed belt provides a higher power density which allows for the smaller belt and pulley system with the same amount of power. These improvements are what make timing belts the most expensive option.

Now that we have gone over how to select the most appropriate belt for your application, we will move on and look at the different types of pulley mountings and the functions for each one. Your least expensive option, where the load is of little concern, is setscrews. These use the friction of the pulley against the flat on the shaft for holding power. They have a keyway which provides a mounting solution for small and medium loads. Another relatively low-cost option for medium loads is a split-hub. An older technology is quick-disconnect, or QD bushings, used for HTD (heat deflection temperature) high load applications. Quick disconnect bushings work by tightening the shaft, which allows the user to mount from either side of the sprocket. The final pulley option is the taper lock, used for the highest load applications. It is sometimes known as the keyless bushing and is designed for maximum flexibility.

Timing belts and pulleys are used in a wide variety of machinery and applications. Power transmissions operate when a motor is driving the pulley system; a common example is driving a car. Conveyance systems work when parts move with or along the belt; for instance a factory conveyor.

Power transmission and conveyance are the primary reasons for selecting an optimal timing belt and pulley system.

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