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 undercord cracking and extending belt existence.
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 methods, tensile cord advancements, and cross-section profiles have led to an often confusing selection of V-belts that are highly application specific and deliver vastly different degrees of performance.
Unlike flat belts, which rely solely on friction and can track and slip off pulleys, V-belts have sidewalls that fit into corresponding sheave grooves, providing additional V Belt surface and greater stability. As belts operate, belt stress applies a wedging power perpendicular to their tops, pushing their sidewalls against the sides of the sheave grooves, which multiplies frictional forces that allow the drive to transmit higher loads. How a V-belt fits into the groove of the sheave while operating under pressure impacts its performance.
V-belts are made from rubber or synthetic rubber stocks, so they have the versatility to bend around the sheaves in drive systems. Fabric materials of varied types may cover the share material to supply a layer of safety and reinforcement.
V-belts are manufactured in a variety of industry standard cross-sections, or profiles
The classical V-belt profile goes back to industry standards developed in the 1930s. Belts manufactured with this profile come in several sizes (A, B, C, D, E) and lengths, and are widely used to replace V-belts in old, existing applications.
They are used to replace belts on commercial machinery manufactured in other areas of the world.
All the V-belt types noted over are typically available from manufacturers in “notched” or “cogged” variations. Notches reduce bending tension, enabling the belt to wrap more easily around small diameter pulleys and permitting better high temperature dissipation. Excessive temperature is a significant contributor to premature belt failure.
Wrapped belts have an increased level of resistance to oils and intense temperature ranges. They can be utilized as friction clutches during start up.
Raw edge type v-belts are better, generate less heat, enable smaller pulley diameters, boost 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 about as wrong as you can get.