Research and design of the precision seeding devic

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Research and design of precision seeding device for pot seedling raising (1)

mechanical automatic pot seedling raising has the advantages of high efficiency, low cost and labor saving; Convenient for factory management and large-scale production; The advantages of rapid seedling growth, no damage to root system, high yield and long-distance transportation have gradually become a modern seedling production mode. The pot seedling production line is mainly composed of a mixer for mixing the substrate, a soil loader for filling the pot with the substrate, a precision seeder for supplying seeds to the pot, a soil covering machine for covering the seed holes, and a sprinkler for watering and wetting the substrate. Among them, the precision seeder is the most critical equipment. This paper introduces the design idea of the seeding device system in the precision seeder, and determines the specific structural parameters

1 general arrangement

in order to improve the production efficiency of the equipment and adapt to various seedling raising cavity plates including staggered grids, this precision seeder adopts a double seeding device system within ± 0.5% of the set value;, Each seeding device contains a double row of seed suction needles. During the seeding process, the conveying line carrying the pot runs continuously without stopping, and each tray of the pot can sow up to 4 seeds; The two sets of vibrating seed discs are arranged back-to-back on the same rack, independent of each other and non-interference with each other. The two sets of seeding device systems correspond to them

2 design idea

the function of the precision seeding device is to quantitatively and accurately supply seeds to the seedling pot, which is mainly composed of three parts: a container for seeds with vibration function (hereinafter referred to as the seed tray), a precision seeding graphene as a new star mechanism in the material world to ensure that the seed suction needle moves according to a certain trajectory, a mechanism for seed suction components, etc

2.1 design idea of vibrating seed tray

first of all, in order to facilitate reliable vacuum suction, the seed tray should have the function of making seeds vibrate, and the seeds should not be dispersed. At the same time, the seeds should not jump out of the tray during vibration, that is, the seeds should be close to each other and tend to jump inward during vibration; Secondly, it should be considered that for the sake of vibration effect, the seed tray should not contact with any object that can cause amplitude attenuation at the seed holding part; Moreover, the vibration force cannot be transmitted to the equipment, and vibration isolation pads shall be provided

the design scheme of the vibrating seed disk shall be able to automatically calculate the Zui large air force, upper and lower yield strength, hysteresis ring method, gradual approximation method, non proportional extension strength, tensile strength, compressive strength, any point fixed extension strength, any point fixed load extension, elastic modulus, elongation, stripping interval Zui large value, Zui small value, average value, net energy, turn back energy, total energy, tortuosity modulus, breakpoint displacement x% load Technical features under breaking point load x% displacement, etc.:

(1) it is appropriate to use vibration electromagnet with simple structure and convenient installation as the vibration source

(2) the seed tray container has a certain rigidity and shape. The seed holding part is designed into a "V" shape to automatically concentrate the seeds, and the cantilever structure is adopted

(3) the spring steel sheet is used as the elastic element. After the electromagnet suction is released, the seed plate can be returned

(4) seed vibration uniformity, that is, the seed tray has the function of fine-tuning the level:

(5) the seed jumping track should be an inward parabola to prevent the seed from jumping out

2.2 design idea of precision seeding motion mechanism

the core of precision seeding motion mechanism is the selection of motion trajectory of seed suction needle; The movement track of the needle shall not interfere with the edge of the vibrating seed disk, and the needle shall reach the bottom of the seed disk. In order to improve the yield of cattle, the track travel shall be as short as possible to shorten the time; Secondly, it should be considered that the needle should run smoothly to prevent the seeds from falling during the movement. In addition, it should be considered that the starting (seed suction) and ending (seed discharge) positions of the needle should be accurate, adjustable and controlled

the design scheme of precision seeding motion mechanism should have the following technical characteristics:

(1) it is appropriate to use clean and fast air cylinder as the power source

(2) the mechanism that generates the motion track. The four-bar linkage mechanism can realize a variety of motion tracks according to different layout methods and the length of the rod:

(3) the running speed attenuation mechanism ensures smooth operation, and the compression spring is used as the buffer elastic element

(4) the limit mechanism at the start and end positions shall ensure that the seed suction and seed discharge positions are accurate and can be controlled manually, and the cylinder with adjustable stroke shall be used

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