Synchronous drives represent a modern and efficient system of power transmission. They essentially combine the advantages of mechanical components (gears & chain) and flexible components (flat & V-belts) while eliminating the inherent disadvantages of these components.
The main components of a synchronous drive are the tensile cords, the teeth, rubber backing and tooth facing. Steel was originally used as a tensile cord material. Most belts today use high modulus (low-stretch) fiberglass or aramid fiber as the tensile member. Tensile cord is the load bearing element of the synchronous belt. The belt teeth are molded of a hard rubber compound jacketed with a tough, abrasion resistant nylon tooth facing. The compressive and shear strength of the teeth exceeds that of the tensile cords when there are at least six teeth in mesh with the driver pulley. A durable rubber backing encases the load bearing tensile cord. It protects the cords from dirt, oil and other contaminants, as well as frictional wear when a backside idler is used.
Synchronous belts operate on a basic principle: molded teeth of the belt and mating grooves of the pulley make positive engagement. The teeth enter and leave the pulley in a smooth rolling manner with low friction. This positive engagement results in exact shaft synchronization, elimination of slippage and speed loss common to v-belts. Synchronous operation at speeds higher than most chain drives.
When to use a synchronous belt drive? There are many situations. For example, high mechanical drive efficiency and energy savings are required. Compact drive layout is necessary. Low maintenance is required or low noise is required.
All synchronous belts operate on the positive engagement principle. Chains operate on the same principle but synchronous belts have many superior characteristics. The latter wrap around the pulley by means of flexion and not by rotation of articulated parts which eliminates one of the causes of wear and noise. With them, the required take-up allowances for tensioning are significantly less. Synchronous belts have no hidden costs. They have larger availability of ratios and lengths.