Carefully consider the essential difference between the lower chain drive and the gear drive. The speed ratio of the chain drive is not constant because the chain will become a broken line once it enters the sprocket. Those who pay attention will find that the chain wrapped on the sprocket The centers of the connecting pins are connected to each other to form a polygon, so the chain drive is equivalent to a belt drive between two polygons. The chain speed of each chain link changes from small to large and then from large to small. This is the unique characteristic of chain drive. Polygon effect, so in general, the transmission ratio and speed of the sprocket refer to the average speed ratio and average speed, while the gear refers to the instantaneous speed ratio and instantaneous speed, which is also impossible for the chain drive to be used for motion accuracy. The reason for higher requirements is that when the number of sprocket teeth z is smaller, the chain pitch p is larger, and the rotation speed is higher, and the polygon effect of chain transmission is more serious.When the driving sprocket rotates at a constant speed, the angular velocity of the driven sprocket and the instantaneous transmission ratio of the chain drive change periodically. cause dynamic loads.