Abstract
Abstract: Dibble-type transplanting device is a core component of dibble-type transplanting machine, and the structural size and the movement rules directly affect the quality of seedling planting. At present, dibble-type transplanting machine in the transplanting process appears that the up-film hole size is too large, and hence the transplanting machine is easy to tear and scrape film, as well as other issues. Starting with the structure parameters of transplanting machine and analyzing the movement characteristic coefficient, the up-film hole size is studied. First of all, the design of the parts of seedling cup, spatial cam, cup mouth and so on is improved, and the three-dimensional model of improved planting device is established through Pro/E. The motion simulation is carried out and the interference is checked; on this basis, the planting device is manufactured. Through the field contrast test, the impact of 2 kinds of planting devices with the caliber of 8 × 8 and 6 × 6, on the up-film hole size is analyzed. And then through changing the movement coefficient, the change regulation of the effect of the coefficient on the up-film hole size is studied. The hole size in the process of transplanting can be measured with transverse and longitudinal size; the transverse size is formed on the surface of the soil when planting device mouth is fully opened, and its direction is vertical to the machine. When the planting device carries composite motion which includes horizontal and circular movement, the movement of the planting device is cycloid form, and at this time, machine direction is longitudinal size. The main purpose of this paper is to reduce the vertical and horizontal dimensions of the film by improving the structure and to improve the planting performance by analyzing the performance parameters of the plant. The test shows that the up-film hole size can be reduced through improving the structure of transplanting device, and especially on the transverse hole size, it is averagely reduced by 45% compared with previous device. When the movement characteristic coefficient is equal to 1.238, the decrease is the most, reaching 49.3%. Meanwhile it is better on longitudinal hole size, which is averagely reduced by 20%. As same as transverse size, when the movement characteristic coefficient is equal to 1.238, the decrease is the most, reaching 24.5%. The changes about longitudinal hole size mainly depend on the movement characteristic coefficient, which is the ratio of circumferential velocity of device to tractor speed. Transplanting machine drive system is composed of 2 chain drives. The power is transmitted to the spindle through the sprocket 1, and the sprocket 3 on the spindle will transmit the power from the sprocket 2 to the sprocket 4 to drive the work of transplanting mechanism. The number of the teeth in sprocket 1, 3 and 4 will not change. By changing the teeth number of the sprocket 2 on the transmission system, change the transmission ratio, and then change the value the coefficient which is taken to be 1.008, 1.047, 1.088, 1.136, 1.184, 1.238 and 1.361, respectively. Observing the changes of the longitudinal hole size through transplanting, it reveals that the motion coefficient has larger effect on longitudinal hole size. When the coefficient gradually becomes larger, the average value of transverse and longitudinal hole size first decreases and then increases; when the movement characteristic coefficient is equal to 1.238, the transverse and longitudinal hole sizes are the smallest, the average value of transverse size is 18.5 mm, and that of longitudinal size is 71 mm. The average planting distance remains at around 400 mm. The leakage rate is 1.07%, the injury rate is 0.71%, and the qualified rate of upright degree is 92.6%. It proves that the coefficient has the optimal value. This conclusion provides the basic data and theoretical basis for reducing the up-film hole size and performance design of the dibble-type transplanting machine.
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