Synchronous toothed belt is abbreviated as synchronous belt, also known as timing belt. It is similar to common belt transmission methods such as V-belt and flat belt, and is a flexible transmission form.
Compared with ordinary belt transmission, synchronous toothed belt has the following characteristics:
① the strength layer made of steel wire rope has very little deformation after being loaded, the pitch of the toothed belt is basically unchanged, there is no relative sliding between the belt and the pulley, and the transmission ratio is constant and accurate;
② the toothed belt is thin and light, and can be used in high-speed occasions. The linear speed can reach 40m/s during transmission, the transmission ratio can reach 10, and the transmission efficiency can reach 98%;
③ the structure is compact and the wear resistance is good;
④ due to the small pre-tension, the bearing force is also small;
⑤ the manufacturing and installation precision requirements are very high, and strict center distance is required.
Since the synchronous belt mainly relies on the positive pressure of the tooth surface to transmit force, its pulley size and center distance are relatively small compared with V-belt and flat belt, and the maximum reduction ratio is only 1:10. Its transmission efficiency can reach 99.5%, the belt speed can reach 50 m/s, the transmission power can reach hundreds of kilowatts, the positioning accuracy can reach 0.05 mm/300 mm, and it is oil-resistant, moisture-resistant, and does not require lubrication.
Therefore, synchronous belts can not only be used to transmit motion and power, but also can be used in motion control systems to position mechanisms. The early synchronous belt tooth profiles were all trapezoidal. After the 1980s, arc tooth synchronous belts were developed. They have more reasonable stress distribution than trapezoidal tooth synchronous belts and can withstand greater loads.
