Engineering a notched belt is certainly a balancing act between versatility, tensile cord support, and tension distribution. Precisely formed and spaced notches help to evenly distribute tension forces as the belt bends, thereby helping to prevent undercord cracking and extending belt life.
Like their synchronous belt cousins, V-belts have undergone tremendous technological development since their invention by John Gates in 1917. New synthetic rubber substances, cover materials, construction methods, tensile cord advancements, and cross-section profiles have led to an often confusing array of V-belts that are highly application particular and deliver vastly different degrees of performance.
Unlike toned belts, which rely solely on friction and may track and slide off pulleys, V-belts possess sidewalls that match corresponding sheave grooves, providing additional surface area and greater balance. As belts operate, belt pressure applies a wedging power perpendicular with 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 china V-belt fits into the groove of the sheave while working under tension 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 various types may cover the share material to provide a layer of protection 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 produced with this profile can be found in a number of sizes (A, B, C, D, Electronic) and lengths, and are widely used to displace V-belts in older, existing applications.
They are used to replace 
belts on industrial machinery manufactured in other parts of the world.
All of the V-belt types noted above are typically available from producers in “notched” or “cogged” variations. Notches reduce bending stress, permitting the belt to wrap more easily around little diameter pulleys and allowing better high temperature dissipation. Excessive warmth is a significant contributor to premature belt failure.
Wrapped belts have a higher level of resistance to oils and intense temperatures. They can be used as friction clutches during start up.
Raw edge type v-belts are more efficient, generate less heat, allow for 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 1 problem: that approach is approximately as wrong as you can get.