Design And Experiment Of Inverted-fin Shaped Model-hole Wheel Variable Seed Metering Device For Both Wheat And Rapeseed

In Anhui Province,the mechanized planting of wheat and rapeseed has similar sowing dates and similar operating procedures,but lacks dual-purpose precision seeding equipment due to the large differences in the physical and mechanical properties and agronomic seeding rates of wheat and rapeseed.The difficulty in ensuring the consistency of row displacement under vibration environment.In this paper,based on the mechanism variable seed metering principle,a wheeled wheat and rapeseed dual-use variable seed metering device with inverted-fin shaped model-hole structure was designed.The theory of particle dynamics,discrete element numerical simulation,comparative analysis and variable seed metering were applied.The method of combination of experiments was carried out to study the type optimization of the seed metering mechanism and the performance of variable seed metering.Its main research conclusions were as follows:(1)Three commonly used varieties of wheat and rapeseed in Anhui Province were selected,and the basic physical parameters and tribological parameters of the seeds were measured.The determination of the degree provides a basis,and the contact characteristic parameters between the seed and the seed meter in the discrete element numerical simulation were determined.(2)Based on the physical and mechanical properties of seeds,the relevant parameters of the key components of the seed metering device were determined,the working principle of the seed metering device was expounded,and the curve equation of the inverted-fin shaped model-hole was fitted.Agronomic requirements determine the key parameters of the model-hole wheel,put forward the inverted-fin shaped model-hole,and design the variable seed metering mechanism and other components of the seed metering device.(3)The discrete element numerical simulation of the seed filling process of the seed metering device was carried out,and the effects of the model-hole type,vibration frequency and working speed on the seed filling process were studied.The working speed significantly affects the seeding rate,while the vibration frequency has no significant effect on the seeding process;the inverted-fin shaped model-hole type has strong seeding adaptability and stability,and the population in the seeding chamber has a high migration speed,and the disturbance effect better,higher filling efficiency.(4)The effect of vibration frequency on the seed metering performance of the seed metering device.The experimental results show that the seed metering device has better seed metering adaptability under the vibration environment,and the vibration factor has no significant effect on the seed metering rate.The results of the optimization test of the model-hole pattern and the test of the seeding performance show that the rotational speed and the model-hole capacity opening significantly affect the seeding rate,and the inverted-fin shaped model-hole pattern was better.The wheat seeding rate ranged from 300 to 3200g/min,the coefficient of variation of the stability of seeding rate was not more than1.3%,and the coefficient of variation of the consistency of each row was not more than 3%.It shows that when the operating speed of the unit was not more than 7.0km/h,the relative deviation between the experimental value of the seeding rate and the theoretical value was not more than 5%,and the coefficient of variation of the total displacement stability was not more than 1%,and meet the requirements of agronomic sowing.