Design And Simulation Experiment Research On The Key Components Of Injection No-till Corn Planter With Straw Fixed By Roller

As the strategic position of sustainable agricultural development continues to increase,conservation tillage technology has been more widely valued and vigorously promoted,making the application of no-tillage sowing technology more widespread,and the types and n umbers of its machinery are increasing.The existing no-tillage planters mainly have the following two working methods:one is to use a disc cutter to"shear"the covering of the surface straw residues and so on;the other is to use a kind of special knife"removes"the ground cover.It clears the sowing zone and then digs the sowing,and when the next sowing zone is cleared,the covering is thrown back and moved back to the original sowing zone.The above two methods can achieve no-till seeding,but there are problems such as easy clogged,large disturbance of soil and straw,large load on working parts,large power consumption,and environmental pollution.In response to the above problems,a injection-type no-till corn seeding mechanism with straw fixed by roller was studied.The roller was used to compact and distribute the straw.Seeds discharged from the seeding device enter the hole-forming device via its rod,and the hole-forming device effectively opens and closes and implants the seed into the hole.The main work of the thesis is as follows:（1）Analysis of hole-forming trajectory and selection of mechanismBy analyzing the characteristics of the injection-type no-till seeding mechanism,the design requirements of the mechanism were determined,and the absolute trajectory of the hole-forming device was determined to be a"gate"shape.The cam-crank linkage rod combination mechanism is used as a prototype to innovate the design of a double-cam no-till cavitation mechanism that can form an absolute motion trajectory of a"gate"shape.（2）Design of double-cam type trajectory forming mechanismAccording to the characteristics of the injection-type no-till seeding mechanism,the parameter combinations of the velocity compensation cam and the cavitation cam were determined through constraint analysis:the velocity compensation cam’s thrust displacement ₁h=L/2（L is the plant spacing）,the thrust angle ₁d=180,the return angled₂=180;the cavitation cam displacement ₂h=100mm,thrust angled₃=90,return angled₄=90,angle of reposed₅=180.According to the principle of no impact and small inertial force,the motion law of th e velocity-compensating cam push rod is selected as the combined motion law of constant velocity and sinusoidal acceleration,and the motion law of the cavitation rod is the trapezoidal acceleration motion law.According to the motion law,the mathematica l model of the cam contour is established.Proposed and applied a cam generation method based on the mathematical model of the curve and VB.NET.Through the auxiliary design system,the mathematical model of the curve of the velocity compensation cam and the cavitation cam was driven according to the interface parameters to drive its 3D model in CATIA automatically generated.The CATIA DMU simulation results show that:the double-cam cavitation mechanism can form the absolute motion trajectory of the"gate"shape,theoretical analysis and auxiliary design system is reasonable and correct.Finally,according to the theoretical model,the corresponding spring is designed according to the condition that the push rod and the cam are not separated.（3）Design of hole-forming deviceBy analyzing the characteristics of injection-type no-tillage planter’s hole-forming device,comparing and referring to similar mechanisms,a cone-type hole-forming device is innovatively designed.The plate,lever,and inner rod drive the hole-forming device to open seeding from the inside,avoiding the problem of scraping straw,entrained soil and straw caused by the structure of the hole-forming device;by modifying the velocity compensation cam profile,the CATIA DMU module is used for the hole-forming device.The trajectory optimization solves the problem of low broadcast depth caused by the eccentricity of the hole-forming device;the rule simulation program is written by using the CATIA knowledge engineering module to determine th e shape and installation position of the baffle through trajectory simulation.（4）Design and selection of other components and technology integrationAnalyze the design requirements of the mechanism for fixing straw by roller,ground wheel and seed metering device,according to which design or select each mechanism,and integrate with the above technologies together,and designed the transmission system and the pitch adjustment scheme using gearbox and"tower cam".（5）Simulation and experiment researchA digital prototype of the test device is built to simulate the actual working conditions,and the interference and collision detection and hole forming effect are researched.The simulation results show that the structure and size design of each component of the test device are correct and reasonable,the hole forming device will not scratch straw,the distance and depth of the hole meet the requirements,the shape of holes is ideal,and the hole forming effect is good.