Design And Experiment Of Self-suction Precision Mung-bean Metering Device

At present,it is still the mainstream form to use small tractor and mechanical seed metering device when seeding in small plots with complex terrain,such as hills and slopes,but the mechanical seed metering device will cause the filling performance of seeds in the hole to decline under the inclined condition,which will aggravate the phenomenon of replaying and missing seeding;the pneumatic seed metering device has strong anti-interference ability and seeding quality when operating on slopes However,the power consumption of the pneumatic metering device is large,leading to a large demand for planter power.In view of the above phenomena,this paper designs a self-priming mung bean precision seed metering device,which uses the mechanical structure to generate negative pressure for seed metering operation.It has the advantages of strong anti-interference ability in slope operation,no need of negative pressure provided by fan to save power consumption,and can meet the demand of precision seeding operation in small plots such as hills and slopes.The main research content of this article is as follows:(1)The triaxial size,density,shear modulus and other physical intrinsic parameters of Bailu9 mung bean seeds were determined and analyzed;Using the discrete element simulation software edem,the coefficient of restitution,static friction and rolling friction between mung bean seeds and contact materials were calibrated by free falling collision method,inclined sliding method and inclined rolling method;The contact parameters between seeds were calibrated by stacking angle test.(2)In this paper,the overall structure of the self-priming mung bean precision metering device was designed.Firstly,the composition and working principle of the overall structure are described.Secondly,the structure of the key components of the seed metering device-seed metering plate,reciprocating suction device and transmission device is analyzed,and the important structural parameters are determined.Finally,the structure of the air chamber and seed chamber is designed.(3)Because the reciprocating suction device of the seed metering device is relatively complex,in order to ensure that the parts of the reciprocating suction device have no interference after installation,and reduce the number of rework processing,this chapter uses the multi-body dynamics software ADAMS to simulate the reciprocating suction device of the seed metering device,and the results show that the motion tracks of the five pistons are consistent,and there is no interference between them The displacement,velocity and acceleration of the plug are similar to sine or cosine curves,indicating that the device meets the requirements of kinematic design.Secondly,the edemfluent coupling simulation method is used to optimize the parameters of the mold hole,and the reliability verification test is carried out.The results show that when the radius r of the lower wall of the groove is 2 mm and the inclination angle of the upper wall of the groove is 57 degrees,the qualified rate is the largest,and the leakage rate and the re absorption rate are relatively small;during the simulation verification test,the overall change trend of the performance indicators of the bench and simulation test is one The simulation results of 4.3 are reliable.(4)In this paper,a bench test and a field test were carried out on the self-priming mung bean precision seed metering device.Among them,the bench test carried out the comparison test of seed discs,and the result showed that the designed scoop-shaped hole seed disc is helpful for assisting seed filling in the inclined state;through the rotating combination design test,it can be known that: for the missed seeding index and the qualified index,the seeding The shaft speed has a significant influence on the height of the seed filling layer;for the replay index,the height of the seed layer has a significant influence on the seeding shaft speed.Using the response surface method to optimize the two factors,it is concluded that when the rotation speed of the seeding shaft is 138r/min and the height of the filling layer is 65 mm,the missed seeding index is 2.97%,the replaying index is 3.43%,and the qualified index It is 93.58%,and all indicators meet the requirements of national standards;the relative error of the missed index between the measured value and the predicted value of the regression model through the bench verification test is 4.4%,the relative error of the replay index is 2.6%,and the relative error of the qualified index is 0.21%.It is basically consistent with the optimization results,which proves the rationality of the regression model.In order to test the practical performance of the seed metering device in a complex field environment,a field test was conducted to prove that the seed metering performance in the field test is inferior to the bench test,and the operating speed is controlled below 10km/h,which can meet the national requirements for single seed Precision seeding requirements.The research content of this article can provide new ideas for the design and research of precision seed metering device.