When designing the pulley of the transmission belt, the structure should be convenient to manufacture, the weight distribution should be uniform, light and excessive internal stress due to casting should be avoid. In addition, the working surface of the wheel groove should be smooth to reduce the abrasion of the drive belt. According to ISO 4183, the working surface roughness of the drive wheel groove for industrial use is 3.2 μm, and for high-performance transmission, it should reach 1.6 μm.