| China is a big producer of rapeseed,and the main area to grow and produce rapeseed along the middle and lower reaches of the Yangtze River in China.The farming conditions and the physical characteristics of rapeseed make the level of mechanization rapeseed cultivation low in this region.Through reading consultation of literature and on-the-spot investigation,a multiple rapeseed planter that can complete rotary cultivation,trench ditching,sowing,fertilizing,press seeds and compact operations in one time,is manufactured,which take the tractor as a driving force,and fit for the pattern of total returning of crop straw in rice-rape rotation area.The main research contents of this paper are as follows:(1)According to the agronomic requirements of rapeseed cultivation and the design requirements of rapeseed planters,this paper has determined the overall structure of integrated machine for rapeseed sowing.The working width of rapeseed planter was determine as 2.3m,the width and depth of the ditches which the machine digs were 20cm,the number of sowing lines was 8 and the row spacing of each line was 30cm.The front part of the machine was equipped with a fertilizing device and a rotary tillage ditching device,a seeding device for opening the seeding ditch was arranged in the middle of the implement,and a covering device and a groove protection device were arranged at the rear,which ensured a series of functions of the machine tool such as rotary farming,trenching,sowing and fertilizing,covering,and compacting.(2)Based on the GB/T 6973-2005 Testing Methods of Single Seed Drills(precision drills),conducted model selection test for the core components of seed metering device.Taken the advance speed of the machine as the experimental factor,analyzed the performance of three different types of seed metering device with the method of single factor comparison test.Taken the vacuum degree of the negative pressure zone and the advance speed of the machine as experimental factors,carry out two-factor full-range level test,so as to obtain the optimum operating parameters of the positive and negative pressure combined seed metering device to provide a theoretical basis for the selection of seed metering device.(3)The key components of the rapeseed sowing machine are selected and designed to improve the performance of the field where with large amount of crop straw and high soil moisture in the rice-rape rotation area.(4)After using SolidWorks software to complete the three-dimensional model of rapeseed sowing machine,conducting the interference detection,and analyzing the center of the rapeseed sowing machine,the result showed that supporting tractors can meet the improving requirements of rapeseed planter.After using ANSYS to conduct vibration modal.analysis for rotary tiller shaft,the result showed that its design was reasonable,as it avoids the frequency of the external vibration source and the resonance vibration phenomenon.(5)This paper has completed the manufacturing of the rapeseed sowing machine,and carried out field trials.The results of field trials show that the slip ratio of tachometer wheel was 10.22%;the total row of seeds consumption consistency coefficient of variation was 1.51%,the each line row of seeds consumption consistency coefficient of variation was 2.65%,the seedling emergence of rapeseed was 85.7%;the width of trench was 19.7cm,the depth of trench was 20.2cm,the stability coefficient of trench was 93.4%,which all reached the design requirements of the rapeseed planter. |
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