In comparison to gear drives, belt drives are more convenient because they allow greater distances between two shafts. This advantage also applies to chain drives, commonly used in bicycles where a considerable distance must separate the pedal and rear wheel. Unlike gear drives, frictionally operating belts such as flat and correas de transmisión offer a natural overload function. Overload results in the belt simply falling through. This prevents major damage to the transmission.
In the worst-case scenario, the belts don’t need to be replaced as much as the entire gears and shafts. The belt drives have another advantage: they are elastic, which is a significant advantage over rigid gears. Due to their damping characteristics correas de transmisión, belt drives are used, for example, in grinding plants or stone crushers, because they offer good damping characteristics. There is also less jerky start and stop behaviour than with rigid gear drives due to the high elasticity of the belt. Still, a high elasticity also results in increased elastic slip.
Due to belts’ positive shock absorption properties, they cannot be designed too elastic or too inelastic. The belt drive has the added advantage of not being sensitive to angular misalignment as long as the axes remain parallel to one another. Many times, this type of misalignment is even deliberate, making it possible to reorient the rotation. In the case of a 180° rotation of the output shaft and cross of the belt, the original rotation direction can be easily reversed.
This drive is also known as a crossed belt drive instead of an open belt drive. Compared to gear drives, belt drives do not require lubrication, so maintenance costs are reduced. Due to the lack of metallic teeth and the relatively soft, elastic belts that drive the pulleys, belt drives emit less noise than gear drives, allowing them to transmit high rotational speeds. Conversely, the pulley is not typically a complete solid wheel like gears usually are.
Because belt drives are lighter than comparable gear drives because of recesses, they are typically lighter than comparable gear drives. However, the above benefits are also countered by disadvantages. The ageing of belts depends on the ambient conditions. Over time, they lose their elastic properties and need to be replaced.
Since belts are plastically stretched over time, they must be re-tensioned regularly. Due to this, belts can only be used within a certain temperature range. Flat belts or V-belts are also disadvantageous for the associated slip, reducing transmission efficiency. Timing belts prevent slippage only due to their positive force transmission, so they cannot be used anywhere else.