| The quality of seeding is directly relevant to the yield of potato and the economic benefits of farmers. In view of the present potato planter has a lot of problems, for example low efficiency, high reseeding rate, high leakage rate and uneven spacing and so on, and considering the agronomic requirements, we design a new type of a cup-belt type potato metering device. The metering device is composed of motor vibration cleaning system, conveyor belt with spoons, tensioning device, shell, pulley(top and bottom), and prevent overhead device, etc. Determine the basic technical parameters by mechanics and kinematics analysis. We design the structure by Solid Works and Inte CAD. Check these parameters through a series of repeated trials and orthogonal tests on the test-bed. The test proved that the theoretical analysis is correct.This metering device will provide development of national potato metering device with a good technical support. The research mainly includes the following aspects:(1). Measured the basic physical properties of potato seeds and obtained theoretical parameters. Including shape, size, density, moisture content, and the friction coefficient of sliding friction angle, roll stability angle, angle of repose, etc.(2). And the kinematics process of seed discharging is analyzed. Including the analysis of the vibration cleaning mechanism, the derivation of the displacement equation in dropping process and the calculation of the critical speed that the seed not be thrown when it climb over the driving pulley. These parameters provide a theoretical basis for the design.(3). Based on the two items above, determined the parameters and designed structure.(4). Constructing the indoor test-bed. Through a series of repeated trials and orthogonal tests to verify the validity of the relevant parameters.Conclusion:(1). Most potato seeds are oval. When the moisture content is 78.63%(w.b.), the volume density of seeds is 631.88kg/m3, the particle density is 1102.25kg/m3, the friction coefficient between steel and seed section, seed epidermis is respectively 0.78 and 0.64, the roll stability angle is 13.7°, the repose angle is between 30° and 32°.(2). Designed an electronic vibration cleaning device. The diameter of the drive wheel is 160 mm, designed a tensioning device and selected a suitable spring. The angle between the seeding duct and horizontal is 77°. Determined the structure of the conveyor belt and the spoon. Designed the prevent overhead device. Produced a prototype.(3). Repeated trials: The empty rate is the minimum when the metering frequency is 240 times/min and the lower hopper is full of potato seeds. The towing height is the minimum when the seeding frequency is 240 times/min and the number of seeds in the hopper is 12.5%. But there has no effect on the stable performance of seeding even the towing height is the maximum(4). Orthogonal tests: Factors, affecting the seeding performance and accuracy, according to the effect intensity from strong to weak are driving wheel speed, vibration intensity and metering device angle. The optimal working condition(seed spacing is 20 cm): Driving wheel speed is 42 r/min, vibration intensity is 0.75, and metering device inclination is 0 °. |
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