The middle of the flat pulley usually needs a convex piece, and the rim of its shaft section is in the shape of a circular arc. The middle part is raised to prevent the flat belt from falling off. What is a flat pulley? A flat pulley is a kind of disc hub transmission part. Generally speaking, the relative size of the flat pulley is relatively large, and the flat pulley is generally cast and forged in the manufacturing process. Flat pulleys are usually manufactured by casting in designs with relatively large sizes. The material is generally cast iron, because the performance of cast iron will be compared.