Study On Motion Characteristics Of Cotton-Seed In Dibbler And Mechanism Of Clamping Seeding

Seeders are core working components of planter, which determine the working performance of the planter derectly. As cotton is main and characteristics crop in XinJiang province, a studying was carried out on the motion characteristics of cottonseed in clamping dibbler and the mechanism of clamping seed-getting of clamping dibbler in this paper through the condition of XinJiang province. Air suction cotton precision planting technique has been widely used in cotton precision seeding at present in Xinjiang. Compared with air suction cotton precision seeding, clamping cotton precision dibbler use traditional mechanical way to achieve precion seed-getting, who has the advantages of simple structure, low cost, less energy consumption, convenient in use and maintenance, and a promising prospect for commercial production. In view of the now problem that operating vibration and seed fluidity have relatively big influence on the working properties of the clamping cottonseed precision dibbler, at first the characteristics of agricultural materials of cottonseeds which are the action object of dibbler is tested in this paper, and the motion law of seeds in seed room is studied, and the seed-filling arch and operating vibration of dibbler is introduced, based on those, the structure of dibbler is improved. Then the working process of improved dibbler is analyzed by high-speed camera. At last the main influencing factors of dibbler performance are studied by the quadratic regression general revolving combination design and statistical method, and the seed-getting device of dibbler is optimized. The mainly conclusions are as following:1)The shape of cottonseeds is between conical and oval, whose natural angle of repose is generally between 30°to 35°, after coating the surface of coated cottonseeds is more rough than that of uncoated, which lead to the natural angle of repose is increased 2°～4°. At first cottonseeds deformation under pressure is linear relationship with pressure, with more pressure and stress deformation is no longer a linear relationship, then there is a seed coat breaking point and the breaking point of matter enclosed in seed coat, and the damage load of cottonseeds is between 10N and 110N.2)The critical depth of seeds group refers to the maximum depth of seeds group in seed room when the whole seeds group slide relatively along the inner ring of seeds room. The critical depth that the seeds slide along the inner ring of seeds room is relative to friction coefficient of seeds room, the larger the radius of seeds room is and the smaller friction coefficient is, the larger the critical depth is.3)If the moving seeds in seeds room do not fall along the surface of seeds group, the seeds group will fall wholly along the inner ring of seeds room. If seeds fall along the surface of seeds group, the seeds rise along the inner ring of seeds room, and the seeds group will do circumferential motion in one side of seeds room. It is an important basis to discriminate the wholly falling or rising of seeds group along the inner ring of seeds room, accordingly if the seeds of the surface of seeds group fall along the surface of seeds group.4)There are two kind of vibration of dibbler in field operation, one is single-point vibration, and another is multi-point continuous vibration. When the operating speed of dibbler (v) is equal to 1.0m/s in unplowed fields, the vertically upward acceleration of single-point vibration is close to 33 m/s2, and the vertically downward maximum acceleration is about 9.5 m/s2, Accordingly, the vertically upward acceleration of multi-point continuous vibration is close to 23 m/s2, and the vertically downward maximum acceleration is about 9.0 m/s2. That is to say, when dibbler is in vibration, there are hypergravity and weightlessness also.5)The seed-getting devices of dibbler was improved, and the seed-protecting track and the seed-filling devices were installed, then the seed-filling probability of the improved dibbler is increased, and the author made the conclusion that the seeds can remain in the seed-clamping mouth of dibbler on the condition of operating vibration. The experiment indicated that the improved dibbler increase the reliability of seeds, and decrease the influence of vibration on precisely seed-getting.6)Based on the analysis from high-speed camera, the author comes to the conclusion that the improved dibbler can finish second scouring seed-getting. There are three ways to finish seed-clearing, one is that seeds fall under the gravity along the rotation of dibbler, the other is that seeds is extruded from the seed-clamping mouth which becomes smaller when heavy blocks rotate, the last one is the equilibrium position of seeds is destructed by the rotation of seed-clamping plate so that the seeds fall.7)According to the experimental results, the rate of single seed is maximum when the depth of seeds in seeds room is 7 ~ 9cm, and the rate of single seed will decrease along the increasing or decreasing of seeds room. The rate of multi-seed increase as the depth of seeds in the seeds room increase, and the cavity rate decrease as the depth of seeds increase. When the speed increases, the rate of single seed of dibbler decreases gradually , and when the speed of dibbler is 0.8m / s, the rate of single seed is 96.2%, and when the speed reaches 1.2m / s, the rate of single seed drops to 89.4%, which the rate of single seed is 95.4% when the speed is 1.0m / s. The resowing rate changes little when the speed of dibbler is less than 1.1m / s, but the resowing rate increases faster when the speed of dibbler is more than 1.1m / s, among them the resowing rate is 2.6% when the speed is 1.0m/s, and at a speed of 1.2m / s the resowing rate is 7.3%.The rate of hole increases slightly with the speed of growth, and it increase from 1.5% to 3.4% within the testing speed. The broken rate of seed is zero.8)Based on test designs, the regression model about the seed-metering performance index of dibbler and the size factor of seed-clamping mouth was built. The research concludes that the square of the splint length has maximum influence on the rate of single seed by variance analysis, and the splint length has maximum influence on the resowing rate, and the opening of seed-clamping mouth has maximum influence on the cavity rate. At last by optimization, the best parameter combination of the seed-clamping mouth is: the length of seed-clamping plate L = 4.5 (mm), the width of seed-clamping mouth W = 5.7 (mm), the opening of seed-clamping mouth H = 7.5 (mm)...