Engineering a notched belt is a balancing act between flexibility, tensile cord support, and tension distribution. Precisely designed and spaced notches help evenly distribute stress forces as the belt bends, thereby assisting to prevent undercord cracking and extending belt existence.
Like their synchronous belt v belt china 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 resulted in an often confusing array of V-belts that are extremely application specific and deliver vastly different levels of performance.
Unlike smooth belts, which rely solely on friction and will track and slip off pulleys, V-belts possess sidewalls that fit into corresponding sheave grooves, offering additional surface area and greater balance. As belts operate, belt pressure applies a wedging push perpendicular to their tops, pressing 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 operating under pressure impacts its performance.
V-belts are manufactured from rubber or synthetic rubber stocks, so they have the flexibility to bend around the sheaves in drive systems. Fabric materials of varied kinds may cover the stock material to supply a layer of security and reinforcement.
V-belts are manufactured in a variety of industry standard cross-sections, or profiles
The classical V-belt profile dates back to industry standards developed in the 1930s. Belts manufactured with this profile can be found in several sizes (A, B, C, D, Electronic) and lengths, and so are widely used to replace V-belts in older, existing applications.
They are accustomed to replace belts on industrial machinery manufactured in other parts of the world.
All the V-belt types noted above are typically 
available from manufacturers in “notched” or “cogged” variations. Notches reduce bending tension, permitting the belt to wrap easier around little diameter pulleys and permitting better high temperature dissipation. Excessive warmth is a significant contributor to premature belt failure.
Wrapped belts have an increased resistance to oils and intense temperature ranges. They can be used as friction clutches during set up.
Raw edge type v-belts are more efficient, generate less heat, allow for smaller pulley diameters, boost power ratings, and provide longer life.
V-belts look like relatively benign and simple pieces of equipment. Just measure the top width and circumference, discover another belt with the same dimensions, and slap it on the drive. There’s only one problem: that strategy is about as wrong as you can get.