Synchronous toothed belt is referred to as synchronous belt, also known as timing belt, which is similar to the common V-belt, flat belt and other belt transmission methods, and is a flexible transmission form. The synchronous toothed belt is made of steel wire rope or glass fiber rope as a strong layer, and the outside is covered with polyurethane or neoprene, and the inner periphery of the belt is made into a tooth shape to make it mesh with the toothed belt pulley. Because the deformation of the strong layer is small after bearing, the circumference of the toothed belt can be kept unchanged, so there is no relative sliding between the belt and the pulley, so as to ensure the synchronous transmission and the transmission ratio is constant.