Design And Test Of The Recision Seeder In Wheat Plot

As one of the three major grain crops in China,wheat is also one of the main economic crops in China.To improve wheat yield,wheat breeding experts need to do a lot of breeding experiments.However,at present,the professional machinery of China’s wheat plot breeding and sowing is lacking,mainly based on artificial sowing,and artificial breeding labor intensity is high,operating efficiency is low,so wheat breeding mechanization has become an inevitable development.To meet the agricultural requirements of wheat plot breeding and sowing,this paper carried out the design and test of wheat plot precision seeder,the specific research contents are as follows:(1)Taking wheat Xi-nong 223 as the research object,the triaxial dimensions of wheat seeds were measured by statistical method.The results showed that the triaxial sizes of wheat seeds were basically normal distribution.The mean values of wheat seed sizes were 6.83 mm in long axis,3.60 mm in middle axis and 3.11 mm in short axis.(2)Designed a vertical pit-eye wheel precision metering device for wheat.According to the working principle of the pit-eye metering device and the vertical filling method of wheat,its characteristic is that the seeds in the hole are forced to be pushed out by the clearing iron wire installed in the metering wheel to complete the metering.(3)Determined the scheme of seed metering device and simulated the seed metering process by the software of EDEM,analyzed the rationality of the structure and scheme of seed metering device,provided the basis for the optimization of the structure of seed metering device,determined that the diameter of seed metering wheel was 95 mm,the width was 10 mm,the hole structure of seed metering device was pillar ball bottom and the depth was 6mm,the diameter of hole was 5mm,the inner hole of seed metering device shell was 96 mm,and the inner section of seed metering device shell was a V-shaped and U-shaped group.By V-shaped surface structure,wheat seeds were guided between U-shaped ends,so that the long axis of wheat seeds was arranged along the tangent direction of the circle around the socket and eye wheel.The height of V-shaped and U-shaped section was 4 mm.In order to make the seeds in V-shaped surface flow into the U-shaped end surface more easily,the transition part between V-shaped and U-shaped was an arc surface with radius of 6 mm,and the inclination angle of V-shaped section was 67°.In order to avoid the seeds being crushed by the shell during the process of seed cleaning,an arc cutting slot with radius equal to 1.6 mm was rotated on the inner wall of the seed metering shell opposite to the hole on the socket-eye wheel.(4)A three-factor and three-level quadratic regression rotation orthogonal combination test was performed using bench tests.Multiple regression analysis and variance analysis were used to obtain a significant order of influence on various performance indices.Using Design-Expert software,there is an interaction between the number of seed cells on the seeding wheel,the U-shaped end faces spacing inside the casing of the seed-metering device and the rotating speed of the wolf wheel.The test results are optimized to obtain the best level of seeding performance.The number of seed cells is 38;the spacing of the U-shaped end faces inside the housing of the seed-metering device is 5 mm;the rotation speed of the socket wheel is 20 rpm.The verification tests showed that acceptance index of the particle spacing can reach 95.92%.(5)Completed the design,trial production and field test of the seeder.According to the agronomic requirements of wheat plot breeding and the research of seeders in related fields at home and abroad,a design scheme of precision seeders for wheat plot was put forward,and a prototype was trial-produced,and field experiments were carried out.The results of bare seeding experiment on the ground showed that the walking speed of the prototype was 0.37m/s,the qualified index of seed spacing was 85.57%,the replaying index was 3.61%,the missing seeding index was 10.82%,the broken rate of seeds was 0%,and the variation coefficient of seed spacing was 15.63%.The trench seeding experiment showed that the walking speed of the prototype was 0.37m/s,the qualified index of seed spacing was 74.57%,the replaying index was 10.63%,and the missing seeding index was 13.97%.Seed breakage rate was 0%,the coefficient of variation of grain spacing was 19.29%.The results of bare sowing and furrow sowing could meet the agronomic requirements.