| In recent years,the demand for vegetables in my country has gradually increased,which has led to an increase in the area of vegetable cultivation.Under this trend,the research on vegetable planting devices has important value for improving the performance of planting devices.At present,the proposal of a precision seeding device for sowing vegetables is proposed,but the precision seeding device produced in China is easy to cause damage to the seeds,the seeding efficiency is low and the qualification rate is poor;High,but expensive and expensive to purchase.Therefore,in this study,the pneumatic seeding mechanism and the honeycomb seeding mechanism are used in combination to reduce the cost of purchasing a precision seeding device.First,the overall structure is designed,and the internal flow field is simulated and analyzed,and then virtualized by Adams software.Test,and finally carry out a bench test to obtain the optimal parameter combination of the combined seed metering device.The main research contents of this article are as follows:(1)Design the overall structure and key components of the combined seed metering device,determine the circumference of the pneumatic seed disc,the hole and the diameter of the hole;design the seed wheel,determine the number of blades and Maximum diameter;the diameter of the honeycomb seeding disc is determined according to the diameter of the seeding disc on the market.(2)A theoretical analysis of the working process of the combined seed metering device is made to clarify the minimum negative pressure for absorbing a seed during the seed suction stage.The negative pressure required during the seed carrying stage is much smaller than the negative pressure during the seed sucking stage.What is needed for the stage is higher than Pmin.The parameter equations of seeding speed and motion trajectory during seeding are established,which provides a theoretical basis for the installation of honeycomb seeding mechanism.The parameter equation was established for the seeding stage,and it was found that the minimum inclination angle required for the honeycomb seeding disc during seeding was 2°.(3)Fluent software is used to analyze the pneumatic seeding mechanism in the combined seeding device to determine the position of the negative pressure inlet;change the number,diameter and shape of the negative pressure cavity of the pneumatic seeding disc.The results show that the change of the number of holes,diameter and shape of the negative pressure cavity has almost no effect on the distribution of the flow field of the gas chamber.Afterwards,fluid simulations were carried out on four different hole shapes to determine the hole shape of the pneumatic seed disc.(4)Using Adams software to conduct virtual tests on different materials and different inclination angles of the honeycomb seeding trays,and finally determine the angle of the honeycomb seeding tray materials and the inclination of the molding holes.Afterwards,a virtual experiment was conducted on the effect of the number of holes,diameter and height of the honeycomb seeding disc on the success rate of seeding.The results showed that the number of hole and diameter of the honeycomb seeding disc had a greater impact on the success rate of seeding Large,and the seeding height has little effect on the success rate of seeding.(5)Carry out a bench test on the combined seed metering device.First,perform a single factor and orthogonal test on the pneumatic seed metering mechanism.Through the range and variance analysis,the parameters when the pneumatic seed metering mechanism works best are determined,and then The pneumatic seeding mechanism and the honeycomb seeding mechanism are used in combination to perform single factor and orthogonal tests.The test results show that:the rotational speed of the pneumatic seeding disc is 18r/min,the diameter of the pneumatic seeding disc is 2.4mm,the vacuum value is 3.5kPa,the number of the honeycomb seeding disc is 24,the diameter of the type hole is 13mm,and the seeding When the height is 60mm,the working performance of the combined seed meter reaches the optimal level.(6)The single-disk double-row test results show that the plant spacing is linearly related to the rotation speed of the conveyor belt.When the rotation speed is 30r/min,the plant spacing is 75mm,which meets the agronomic requirements;the change of the conveyor belt speed has no significant effect on the line spacing,and the width of the honeycomb seeding mechanism It has a greater impact on line spacing.(7)Observing the seeding process of the combined seed metering device through a high-speed camera,and found the phenomenon of multi-suction,leaking suction,re-throwing,missed dropping,etc.,and found the reasons for the re-investment and missed dropping of the combined seed metering device. |
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