| Sowing is the fundamental part in the process of agricultural production,and the quality of sowing is the premise of increasing agricultural production.With the development of agricultural production technology and the improvement of seeding mode,the sowing technology and the seeding machinery in our country have made good development in recent years.The seed metering device is the core working part of the seeder,and its characteristics and working properties have a direct influence on the seeding quality.It has become the development direction of precision metering device to adapt to high speed operation.The existing pneumatic metering device generally adopts mechanically agitated seed,pneumatic and vibratory seeding boiling to improve the performance of seed-fill.However,it has complex structure and lower seeding effect.Pneumatic metering device is mostly single row seeding device.The installation position and quality of seed metering device on seeding unit are strictly restricted.In view of the problems in the process of seeding in pneumatic seeding device,combining with the simplified seeding monomer at the same time,improving the sowing quality and adapting to the agronomy requirements of wide,high speed and narrow row of soybean in planting process.A compact soybean precision metering device was designed in the way of collision seed clearing and slippage to absorb seeds.The main contents of the research are as follows:(1)In this paper,the method of sliding seed suction and colliding seed clearing were adopted to design the centralized row soybean precision metering device.The overall structure and key components design of the centralized row soybean precision metering device were carried out.The working principle and other structures of the metering device were analyzed in detail,and the structural parameters such as drum diameter,diameter of suction hole,number of axial suction hole and row number of radial suction hole were obtained by theoretical analysis.And the position of mounting hinge point of the sealing device gas chamber was got.(2)Based on the theory of mechanics,the metering process of precision metering device is analyzed.The mechanical model of two stages in seed filling process is constructed,and the relative factors affecting seed adsorption are obtained.The relative velocities of falling seeds and adsorbed seeds were compared and analyzed by using the synthesis theorem of point,and the curves of the relative velocity of falling seeds relative to the cylinder and the times of passing through the holes were obtained.(3)Using EDEM simulation software analysis of seed falling collision process of centralized row soybean precision metering device were carried out,and the movement law of soybean population in seeding device was clarified.The track of falling seed flow and the influence of absorbed seed of velocity on the seed flow in the process of seed clearance were analyzed,which provided a reference for further optimizing of the structure on seeding device.(4)The single factor test and multi-factor test of the centralized row soybean precision seed metering device were carried out by using the JPS-12 type seed metering tester,and using high speed camera system for dynamic image analysis of seeding process.The seeding influence of the structure parameters such as the width of the seed guide plate and the angle between the guiding deflector were obtained by the single factor test.The influence of working parameters such as air pressure and working speed on the seed metering performance of the metering device is studied.Taking the air pressure value and the working speed as the test factors,the qualification index A,the replay index D and the missing seeding index M as the evaluation indexes.The quadratic rotation orthogonal combination test was carried out.Through parameters optimization,when the pressure value was 5.2 kPa and the operating speed was 8 km/h,the seeding performance of the seed metering device is the best,and the optimized results were verified by the verification test. |
PDF Full Text Request