The circular belt is a transmission belt with a circular cross-section, which can be driven by free bending.
This belt is mostly made of polyurethane and usually has no core. It has the simplest structure and is easy to use. Circular belt has opened up a new way for belt transmission. The demand for small machine tools, sewing machines and precision machinery in the world has increased dramatically and has great potential in the future.
Tooth belt, also known as synchronous belt, can be divided into two types: single-sided belt and double-sided belt. The former is mainly used for single-axle transmission, while the latter is multi-axle or reverse transmission. It is another high-efficiency transmission belt emerging in the world since 1980.
According to the shape of the teeth, the belt can be divided into trapezoidal and circular arc. The synchronous belt with circular arc teeth bears the largest torque. From the material used, the teeth belt can be divided into two types: rubber type and polyurethane type. The former can be divided into ordinary rubber (usually chloroprene rubber) and special rubber (mostly saturated nitrile-butadiene rubber).
Their structure is composed of a strong layer of steel cord or glass fiber and an outer rubber layer or polyurethane rubber layer formed by rubber and nylon cloth.
Tooth belts, including multi-wedge belts, have developed rapidly in the developed countries in the past 20 years. They are constantly eroding the market of traditional metal gears, chains and rubber flat and triangular belts. At present, besides being widely used in automobile and traditional industries, it has been further extended to the transmission of OA machines (office equipment), robots and other precision machinery.
Because of the elastomeric teeth inside the belt, which can realize synchronous transmission without sliding, and has the characteristics of lighter and less noise than the chain, more than 80% cars in Europe and 40% cars in the United States have been equipped with the belt. China produced 2 million automobiles in 2000, and more than 7 million gear belts were needed.
Compared with square belt, circular belt has more power transmission and quietness. As a new generation of environmental protection belt, circular belt has a wider range of applications. Now, it has begun to become the object of use of domestic and industrial sewing machines, typewriters and photocopiers, which have strict requirements on synchronous transmission and noise.