Design and test on seed metering device with variable capacity model-hole roller

In order to solve the problems along with adjusting the seeding capacity by using model-hole roller seed metering device, a variable capacity model-hole roller seed metering device was developed based on an eccentric model-hole roller seed meter. The variable capacity model-hole roller seed meter was composed of a model-hole roller and a control ring. Unvaried factor and multivariate factors tests were carried out with five influence factors, which included rotation speed of roller, adjustable tongue, seeding grade, speed and adjustable tongue width. The results showed that the rotation speed of roller, adjustable tongue shape and model-hole size were the key factors which affected seeding uniformity, lines uniformity and broken rate. The seed meter had a preferable performance at the rotation speed about 30-50 r/min; and the concave round tongue was better than the flat one. With length of the model-hole increasing, the seeding uniformity, lines uniformity were improved and broken rate decreased. The seed meter is suitable for drilling for all types of small-size seeds with the designed structural dimension.