Triangular belt generally refers to wrapped V-shaped belt. Since 1960s, in order to improve the durability of transmission belt, flanged V-belt has appeared. This kind of cutting edge V-shaped belt has been developed rapidly because there is no coating on the side of the belt structure, the belt body is very soft, the bending resistance is very good, and the fatigue performance is very good. In the 1980s, in order to solve the problems of transmission efficiency and service life decline caused by different lengths of triangular belt, a triangular belt with multiple triangular belts fixed together with flat belts was raised in order to solve the problems of transmission efficiency and service life caused by different lengths of triangular belts.

The V-shaped flat belt, which is commonly called the combined triangular belt, has great advantages, so the phenomenon of replacing the wrapped and cut triangular belt with the V-shaped flat belt has begun to appear. Although this kind of belt combined with flat belt has special requirements for the belt wheel grooves, the belt body is very thin, the contact area with the belt wheel is large, the bending property is good, the belt wheel is reduced, the transmission device can be further miniaturized, energy saving, and the production in the developed countries of the world has increased sharply.