| The Changjiang River basin is the rice and wheat focus areas in China,and the rare rice-wheat rotation cropping in this area.The high yield crops lead to overlarge crop stalks using the method of straw returning into the ditch.The combined machine developed by our research team was to solve the harvesting,ditching and grass filling compound operation.After the harvesting completed,the straw was returned back into the ditch,without earth disturbance and the soil structure destroying,which provided the seeding of no-tillage environment for next crop.The seeding system was designed to cooperate well with the combined machine to realize the seeding of no-tillage operation after the straw’s returning into the ditch.In order to explore the feasibility of the mode of no-tillage seeding with the straw returning back into the ditch,seeding system with the combined machine was validated to improve seeding quality,reduce operation times,simplify the agricultural machine mechanical operation,increase economic efficiency and shorten the work period to harvest seeding season.The study on the seeding system consisted of parametric design,theory research,operation simulation,performance test,and the operation quality test by continuous field experiment study.The main research contents are as follows:(1)Design and experiment of seed-metering mechanism of combined machine seeding systemAccording to the no-tillage seeding environment,the key parts-the seed metering mechanism and furrow ditching mechanism are designed and tested.Based on the working principle of the machine,installation space,the seeding requirements of rice and wheat system,the round metering device system was used as seeding metering device,and arranged in the header above the upper beam along with the box.Mechanical link transmission was used in the Huanghai machine metering mechanism and power source came from advance track,and ensured the metering stop and start to be consistent with the harvest;motor drive was used in Jiangyan machine,and wheel speed was controlled through the electronic speed controller.Through the seeding experiment,sheave wheel was in 2～9 mm,the sheave opening was in 10～60 r/min,rice seeding rate ranged from 2.61 to 24.17 kg/mu,sheave wheel was in 3～10 mm,the sheave opening was in 10～60 r/min,wheat seeding rate ranged from 3.35 to 28.67 kg/mu.Seed sowing quantity test reflect Jiangyan machine design institutions emissions stability coefficient of variation is larger,on this basis,the design of the Huanghai machine kind of agency power forward from caterpillar,linkage transmission,ensuring the kind of start-stop and harvest start-stop,rotating speed of the machine speed.In addition to improve the stability of the displacement of slope above the conveying groove metering device optimization of pipe bending,determine the exhaust pipe bending ideal state.Through the seeding of Huanghai experiment,sheave wheel was in 2～9 mm,rice seeding rate ranged from 2.82 to 25.12 kg/mu,sheave wheel was in 3～10 mm,wheat seeding rate ranged from 7.90 to 40.01 kg/mu.Experimental results indicate the total emissions compared stability coefficient of variation in Jiangyan machine declined,in meeting the requirements of the standard value,meet the demand of the actual planting.In addition,the field test results,the actual amount on the Huanghai machine is smaller from the seeding quantity,seeding amount is less than this machine,raised the sowing quality.Verify the Huanghai machine planting system and transmission mechanism design inclination conveying groove above rows device the feasibility of the optimization of pipe bending.(2)Design and test of furrow opener mechanism of combined machine seeding systemFor the need of no-tillage seeding,stubble breaking and furrow digging in the seeding system,the rolling opener is used as the main thread for the Huanghai combined machine,and the moving opener is used as the main thread for the Jiangyan combined machine.The design and experiment of the furrow opener of the seeding system are carried out.Considering the furrow opener installation space limitation,the notched disc opener,rake disc opener,disc opener with diameter of 160 mm were designed,and analysis of three kinds of straw force disc opener working process,design and analysis of that gap the disc opener blade curve,the maximum vertical force of straw can increase the blade,the opener is easier to cut off the straw stubble.The discrete element method was used on the three disc opener of stubble breaking ditching.Test results show that the disc opener groove size with a gap edge are between 3-4 cm and 3 disc type furrow opener of 160 mm diameter,stubble breaking rate in descending order of the gap disc opener,rake disc opener,disc opener,stubble breaking rate were 31.5%,27.3%,20.6%.Through field test,the breaking performance of three kinds of disc opener was further investigated.The test results show that the groove size of 160 mm diameter disc opener was between 2-3 cm.For 3 kinds of disc opener with 160 mm diameter,the ratio of stubble breaking from big to small was notched disc opener,harrow disk opener and disc opener respectively,and the stubble breaking rate was 25.6%,20.3%and 13.2%respectively.Based on the test results of disc opener on the design of the electric lifting device to replace the original opener rack mounting space opener,make the Huanghai combined machine with 200 mm diameter double disk opener,can opener by ant colony algorithm to optimize the focal point position angle of 72.3°and a lifting device was connected to the ground distance 661 mm,ensure the opener buried depth of up to 60 mm.Through the RecurDyn dynamic simulation of axial force of the telescopic rod lifting device,the penetration process of axial force and maximum value was 2165.8 N,less than the maximum acceptable axial force of 4000 N,which could meet the requirements of opener buried.Field experiments were conducted to investigate the breaking performance of the double disc opener.The results showed that the groove sizes were between 3～4 cm and the stubble breaking rate was 37.8%.The results were better than those of disc opener.By orthogonal experiments,further optimize the factors affecting the Huanghai combined machine seeding quality value,the optimization results showded that the forward speed of the machine was 0.46 m/s;the opener depth was 3.25 cm;the opener of seed tube fixing device hole center to the seed outlet center of the horizontal distance was 16.16 mm,the optimal seeding quality.In Jiangyan combined machine,a sliding knife opener was used as seeding ditches and furrow opener.The angle of the small no tillage furrow opener was 36°,and the angle of the earth gap was 10°.The experiments results showed that the runner groove size was less than 3 cm,the residue removal rate of 15.2%;small ditch no tillage opener size was in the range of 3 to 4 cm,the residue removal rate was 32.9%.(3)Design and experiment of other mechanism of combined machine seeding systemIn order to realize the soil covering function of the seeding system,a soil throwing device was arranged at the upper part of the grass furrow opener,so that the ditching device was thrown out of the soil and was covered with the soil throwing device and covered in the sown area.Soil throwing device was designed by a pair of guide plate and extension plate,plate width was 199.5 mm,the inner circle radius was 450 mm,the outer radius was 800 mm;the extension plate length ranged from 10.6 to 14.2 cm,through field experiments finally determined the optimal length of 12 cm.In order to realize the pressing function of the seeding system,a design press wheel was arranged behind the furrow opener of the grass collecting groove,and the design weight of the pressing wheel was 60 kg,the radius was 125 mm,and the length was 1900 mm.(4)Combined machine seeding system field testThe Huanghai and Jiangyan combined machine were validated by consecutive years field experiments in both summer and Autumn to seed rice and wheat.The 2016 autumn wheat seeding experiments in Huanghai showed that the field seeding depth qualified rate,seeding uniformity variation coefficient,broken rate and dry seed rate were 58.1%,28.7%,0.18%,1.46%;as for the autumn test in 2014,the whole field experiments qualified rate,seeding seeding uniformity variation coefficient,broken rate and dry seed rate were 57.8%,32.7%,0.29%,1.60%,respectively.Experiments results in 2016 were better than that in 2014,which showed a furrow opener seeding mechanism,soil throwing device,a pressing wheel of seed quality had the promoting effect.In 2016 the entire field germination rate was 79.17%,0.48%higher than the control group,the highest yield could reach 478.7 mu kg/,higher than the local production field.The above experiments results showed that the Huanghai combined machine could meet the demand of no-tillage wheat seeding.The 2016 autumn wheat seeding experiments in Jiangyan showed the seeding depth qualified rate,seeding uniformity variation coefficient,broken rate and dry seed rate were 60%,36.9%,1.01%,1.61%;as for the autumn experiments in 2015,the whole field test qualified rate,seeding seeding uniformity variation coefficient,broken rate and dry seed rate respectively.53.3%,35.4%,2.20%,1.71%.The 2016 seeding depth pass rate,broken rate and dry seed rate were better than the standard in 2015,indicating furrow seeding mechanism in furrow opener,metering device,driving device,the form of throwing soil on the improvement of the presswheel seed quality had a certain role in promoting.In 2016 the entire field germination rate was 70.46%,only 1.36%lower than the control group,the highest yield was 298.2 kg/mu.The above experiments results show that the Jiangyan one machine basically meets the demand of no tillage seeding wheat.The 2017 summer rice seeding experiments in Huanghai showed the field seeding depth qualified rate,seeding uniformity variation coefficient,broken rate and dry seed rate were 75.5%,27.9%,0.58%,1.06%;as for summer rice seeding experiments of 2016 in Huanghai,the field seeding depth yield,seeding uniformity variation coefficient,breaking rate and dry seed rate were 73.3%,33.7%,0.56%,0.81%;the autumn of 2015 the whole field test pass rate,seeding seeding uniformity variation coefficient,broken rate and dry seed rate were 51.1%,27.6%,0.71%,1.38%.The 2016 and 2017 seeding depth qualified rate,broken rate,dry seed rate index were better than 2015,and the improve seedingd soil throwing mechanism on the device had certain promoting effect on the quality of seeding in furrow opener.In 2016 the entire field germination rate was 75.88%,the highest yield was 417.62 mu/kg.The above experiments results showed that the Huanghai combined machine basically meets the demand of no-tillage rice seeding.Dry seeding field experiments in the summer of 2016 in Jiangyan showed that rice seeding depth qualified rate,seeding uniformity variation coefficient,broken rate and dry seed rate were 66.6%,33.6%,0.56%,1.63%;in 2016 summer wet rice seeding experiments showed whole field seeding depth qualified rate,seeding rate uniformity variation coefficient,broken bar drying rate,seed rate were 66.7%,24.7%,0.75%,1.54%;as for 2015 summer experiments,the seeding qualified rate,seeding uniformity variation coefficient,broken rate and dry seed rate were 62.2%,35.5%,0.67%,1.72%,for dry seeding,the index in 2016 was better than that of 2015,indicating the improved device had a certain promoting effect on the quality of seeding in furrow opener,metering device and drive form.In the experiments of 2016 dry seeding,the field germination rate was 79.12%,the wet seeding field germination rate was 70.9%,the highest yield of dry seeding was 435.49 mu/kg and wet seeding highest yield was 434 mu/kg.The above experiments results showed that the Jiangyan combined machine basically met the demand of no tillage rice seeding.The autumn of 2016 in the Huanghai farm test results showed that the total cost of machine seeding mode from the harvest takes 166.7 RMB per mu,lower than the local operations of 210.9 yuan per mu,which could save operation cost. |
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