The working surface of the synchronous toothed belt and the rim surface of the pulley are made into corresponding tooth shapes, and the belt drive is driven with meshing. Generally, a thin steel wire rope is used as a strong layer, and the outer bread is covered with polyurethane or neoprene. The center line of the strong layer is defined as the section of the band, and the circumference of the section is the nominal length.
The synchronous toothed belt takes the center line of the strong layer as the node line, and the circumferential length of the node line Lp is the nominal length, and the distance between the corresponding points of the adjacent two teeth along the node line is called the circumferential p, and the modulus m=p/π. The domestic synchronous toothed belt adopts the modulus system. The bands are marked as: Modulus (mm) × width (mm) × number of teeth, i.e. m×b×z. The series of modulus, width and number of teeth, as well as the corresponding specifications between the three, are shown in the table above.