Engineering a notched belt is certainly a balancing act between versatility, tensile cord support, and tension distribution. Precisely shaped and spaced notches help to evenly distribute tension forces as the belt bends, thereby helping to prevent V Belt undercord cracking and extending belt lifestyle.
Like their synchronous belt cousins, V-belts have undergone tremendous technological development since their invention by John Gates in 1917. New synthetic rubber compounds, cover materials, construction strategies, tensile cord advancements, and cross-section profiles have resulted in an often confusing selection of V-belts that are highly application specific and deliver vastly different levels of performance.
Unlike flat belts, which rely solely on friction and may track and slide off pulleys, V-belts possess sidewalls that fit into corresponding sheave grooves, offering additional surface and greater balance. As belts operate, belt tension applies a wedging pressure perpendicular to their tops, pushing their sidewalls against the sides of the sheave grooves, which multiplies frictional forces that permit the drive to transmit higher loads. What sort of V-belt fits in to the groove of the sheave while working under tension impacts its performance.
V-belts are made from rubber or synthetic rubber stocks, so they possess the flexibility to bend around the sheaves in drive systems. Fabric materials of various types may cover the stock material to provide a layer of safety and reinforcement.
V-belts are manufactured in a variety of industry regular cross-sections, or profiles
The classical V-belt profile dates back to industry standards created in the 1930s. Belts produced with this profile come in many sizes (A, B, C, D, E) and lengths, and so are widely used to replace V-belts in old, existing applications.
They are used to replace belts on industrial machinery manufactured in other parts of the world.
All the V-belt types noted above are usually available from manufacturers in “notched” or “cogged” variations. Notches reduce bending tension, permitting the belt to wrap easier around small diameter pulleys and permitting better temperature dissipation. Excessive temperature is a significant contributor to premature belt failure.
Wrapped belts have a higher resistance to oils and extreme temperature ranges. They can be used as friction clutches during set up.
Raw edge type v-belts are better, generate less heat, enable smaller pulley diameters, increase power ratings, and offer longer life.
V-belts look like relatively benign and simple devices. Just measure the best width and circumference, find another belt with the same sizes, and slap it on the drive. There’s only one problem: that approach is approximately as wrong as possible get.