| Corn is the largest food crop in China,its planting area and yield are more than rice and wheat,and it is still increasing in recent years.At present,the mechanization level of corn production in China is still relatively weak,especially in the harvest link.Only by human harvesting corn,labor is very large.Therefore,there is an urgent need for harvesting machinery to replace part of manual labor.Corn header is the key component of corn harvester,which plays an important role in the harvesting process.At present,the header installed on the corn harvester in our country is mostly vertical and horizontal structure,and its ear picking principle is to complete the harvest by stretching the corn stalk and squeezing the corn ear.This principle of ear picking determines that the ear of corn will contact with the ear picking roller directly,which is very easy to cause damage to the ear,resulting in higher grain loss rate.In order to solve the above problems,this study combined with the physical characteristics of corn,researched and designed a kind of corn ear picking device with high efficiency and low loss,and verified the excellence and rationality of the corn ear picking device designed in this study,which provided a reference for the research of corn harvest technology in China.The main contents of this paper are as follows:(1)Taking the corn plant as the research object,the external dimension of the corn plant was measured.Combined with the measured data and the actual appearance characteristics of the corn plant,a three-dimensional model similar to the real corn plant appearance was established by Solid Works software.The bending characteristics of the plant and the mechanical tests of the compression and tension of the stem were tested and analyzed,and the load displacement curves of the tensile and compression of the plant stem were obtained,which provided the basic theoretical data for the structural design of the key parts of the header.(2)Design the key components of the combined header,including the design of the divider,the design of the reel chain,the design of the stalk pulling roller,the design of the stripping board and the design of the auger.This paper analyzes the factors that determine the separating capacity of the divider,the influence of the diameter,working length,inclination angle,rotation speed and machine operation speed of the stalk pulling roller on the working performance of the header,and the calculation of the parameters of the key parts,obtains the size design range and determines the specific size.And through Solid Works software combined with the design size to establish the three-dimensional model of the combined header.It provides the corresponding parameters and simulation model for the simulation analysis of corn plant and header.(3)The rigid flexible mixed model of header and corn plant was established by ADAMS software,and the contact force between the divider and the stalk and whether the bending amount of the stalk was lower than the critical bending angle of the stalk were analyzed to verify the rationality of the design of the divider’s overall dimension.In order to verify the rationality of the design of the ear picking device,the extrusion force of the stem pulling roller on the stem and the impact force of the ear are simulated and analyzed in the process of ear picking.The optimal harvest parameters of the header were obtained.The rotation speed of the stem pulling roller was 750 r / min,the forward speed of the machine was 5km / h,and the inclination angle of the header was 25 degrees. |
