| Peanuts are the most advantage of oil crops in China, whose total output occupies first in the world. The peanut planting mechanization level and the cultivation of comprehensive benefit is low, and it is difficult to expend the scale of production. It is of great significance to improve the mechanization level of peanut planting in Xinjiang area in consequence.According to the characteristics of big mass and broken easily, this paper design a kind of pneumatic peanut precise metering device with the characteristics of using the negative pressure to extract seed, auxiliary clamping device, and seed charge with weight throw. Through the experimental research of the basic material characteristics of the peanuts, we obtain the various parameters of the peanut seeds, such as moisture content, hundred-grain weight, seed volume, natural angle of repose, sliding friction angle, crushing force of the origination, and so on, which establishes the peanut seeds model and is helpful to provide theoretical basis for the design of seed-metering device. With the key design which is based on the auxiliary clamping device of pneumatic type peanut seed metering device, this paper designs the structure of seed-metering device. When the auxiliary clamping device is working, activity blocks move along the CAM contour curve, the CAM and nearest dwell phase’s activities are on the stage of seed-metering taking stage and the auxiliary clamping device will clamp the seed. When the the CAM and the farthest dwell are on the stage of throws seeds and absorbs seeds of the seed-metering device, the auxiliary clamping device will not produce force on the seeds.This paper analyzes the static characteristic of the peanut at the clamping stage, and reach a conclusion that the motion law of the CAM contour curve is the key factors of influencing the peanut auxiliary clamping force. This paper makes use of the MATLAB software in order to analyze and compare the cam profile, such as the uniform motion curve, the sine correction motion curve, a 3-4-5 correction motion, the sine modified constant velocity motion curve, the 3-4-5 times amendments uniform notion curve, and so on, and come to a conclusion that the 3-4-5 curve is the best curve. When the biggest extending stroke of the CAM is 50 mm, the tangent angle of the maximal pressure angle is less than the tangent angle of the allowable pressure angle, which is 0.58, establishing the trajectory curve equation of the cam profile. The cam model is established in the Solidworks software and analyzed by ADAMS,which works out that when the speed of the seed-metering device is 20r/min, the acceleration of clamping seeds of the cam follower is 0.1m/s2.This paper builds the pneumatic peanut precise metering device and text seeding performance. It comes the optimal performance seed and the scope of negative pressure value of the seed-metering device through analysis the single factor experiment of negative pressure and the speed of single factor experiment data. On the basis of single factor experiment, this paper affords to the orthogonal experiment of seed-metering device, draw a conclusion by the extreme difference analyzing that when the negative pressure value is 10.2kpa and the rotate speed of the seed-metering device is 20r/min, the qualified index of the seed-metering device is 92.3%.By the orthogonal test analysis of variance, this paper gets a conclusion that the negative pressure value and rotate speed of the seed-metering device have an extremely significant effect on the qualified index, leak seeding index, and replay index of the seed-metering device.The speed and the interaction of the negative pressure have an extremely significant effect on the qualified index and the leak seeding index, no significant influence on replay index. The capability test provides the direction for future research of the pneumatic peanut precise metering device. |
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