| China is the large rape production country,the rape plant area and total yield are the largest in oil-bearing crops in the world,the annual planting area is about 6.67×106hm2,and accounts for a quarter of the total rape plant population in the world.Rape planting has the weak points of low benefit,high production cost,low degree mechanization,high labor intensity,long retting time,hard sledding.Rape harvest mechanization level was less than 10%in 2013.Low level rape mechanization technology has become the focal factor which restricted the further development of rapeseed industry in China.Rape partition harvest technology which has the advantages of strong daptability is an important way to solve the rape mechanized harvesting on the condition of wide planting area and multiplicity planting system in current.Windrowing technology is difficulty in rape partition harvest technology.The key of this technology is transporting technology and windrowing technology.These works which study the mechanism of the rape stalk windrowing and transporting in the mechanical partition harvesting,development windrower are important to solve the problem of rape partition harvest,to improve the overall level of mechanization of rape production To ensure the safety of grain and oil production in ChinaFocusing on the problem of windrowing and transporting in rape windrowing,the relationship between rape windrowing and rape plant biological traits was studied through the method of combination of Agronomy with Farming Machinery,Agronomic technical regulations for mechanized windrowing was established.Windrow quality evaluation index and influencing factors,Rape stem movement in rape windrowing were studied through the method of combination of theoretical analysis and test,characteristics of rape stem windrowing and transporting were established.Single factor tests and multifactor tests on windrow quality influencing factors were studied through field test,the parameters were optimized,rape windrowing equipment were established.The main study tasks and results were as follows:(1)Rape plants biological characteristics related to windrowing were studied.Rape plants which had characteristics of semi dwarf,lodging resistance,compact plant,concentrated flowering period,the same mature period,pod shattering were suitable for mechanized windrowing.Rape plants biological characteristics related to windrowing including each branch height,each branch length,angle of each branch and stem,largest canopy height,largest canopy diameter,plant height were Screened.Under different planting patterns and different cultivation methods,the effect on windrowing by biological characteristics of rape plants was different.Direct seeding rape was suitable for windrowing than transplanting rape.Seeding time was middle of the month,Planting density was 2-3 ten thousand plants/mu,then the highest yield was gained,plant type was dwarf and compact,It was suitable for Mechanized windrowing.The relationship between rape maturity,optimum windrowing time and windrowing was Studied.The optimum conditions which was suitable for windrowing were gived.Grain water content was about 12%,stem water content was about 15%,70%pod on the plant was yellowish green,spindle central pod was pipa color.Rape straw friction characteristic was studied.Friction angle between rape stem and Q235A plate was 28.05°.Friction angle between rape stem and Rubber conveyor belt was 30.12°Resistance crack characteristics of the pod was studied,Resistance crack index varied between 0.0075 and 0.845,the range of damage power was 0.5031-3.9999N.Windrowing Afterripening was studied.It was found through experiments that afterripening could increase the yield of rape,but it was little impact on the quality of rapeseed.As long as appropriate windrowing time was mastered,the quality of rapeseed could be improved.(2)The rape windrower was designed.According to the design thinking of rape harvest equipment.The windrower was made as the form of header.through quick interface,Supported upper,fastened below,the windrower was hitched on combine chassis.Standard type reciprocating cutter was selected as main cutter,Velocity,acceleration of the cutter was Analysed.The relationship between the displacement and the velocity of cutting knife was given.The relationship between the forward velocity of the machine,cutting speed,cutting knife structure parameters was presented.Optimum cutting speed was 1.5m/s when the main cutting force was minimum.Reciprocating double knife cutter was selected as vertical cutter.It was Installed on the other side of exhaust straw port with the characteristics of ensemble knife blade,direct driving.The relative position between the vertical cutter and the main cutter was gived.The front extending distance between Vertical cutter and main cutter was from 200 mm to 400mm.In the vertical cutter frame stiffness permitting,in order to reduce the disturbance area,this distance couble get large value.The relationship between the vertical cutter installation angle and windrowing loss was analysed.The vertical cutter installation angle was gived,It inclined about 10°-15°backward and outward.The reel has 5 spokes,radius was 500mm,rotate speed was 12?42 r/min,reel pitch was 0.4mm.Based on analysis the action process of reel and rape plants,parameters expression of level and vertical distance between reel and cutter were established.Level distance between reel and cutter could be adjusted from 0 to 276mm.The height of reel center was more than 1100mm.It could be adjusted by hydraulic mechanism.The structure of transport device was studied.correlation between installation angle of transportation part and push angle of reel was gived.Assemble angle of transportation device was from 10° to 20°.The angle which was too large or too small was unfavorable to rape plant windrowing.The positional relationship between the conveying device and the main cutter was studied.Level distance between transportation device front end and cutter was determined by rape plant height,It was less than 300mm generally.Vertical distance between transportation device front end and cutter was less than 125mm,otherwise the accumulation rape plant on the cutter would be transported.Transportation speed was 4m/s.Horizontal toggle mechanism and vertical toggle mechanism were installed beside exhaust straw port.The rape stem on the conveyor belt beside exhaust straw port was threw.Good windrowing shape could got.(3)Influencing factors analysed for windrow quality of 4SY-2 rape windrower.Evaluating indicator on windrow quality of rape windrowing was selected.Quality requirements of rape windrowing were evolved:lossing percent<1.0%,Windrowing angle?45° Windrowing angle difference?30°,Root difference ?150mm,Cutting height?300mmThe rape windrower was a dynamic system that including many input and output variables.Windrow quality mathematical model was used to describe the correlation of windrowing and transporting.Factors influencing the windrow quality mainly included rape biological forms,maturity,the relationship between the structure of the machine parameters.The results of field test showed that rape in the height of 1.3-1.7 meters,and in the yellow ripe stage was much suitable for cutting.The machine speed and the reel speed must be coordination with the speed of the conveyor belt,The working rhythm and speed of stalk on the conveyor belt controlled by the transverse stir device must be coordination with transporting speed of the conveyor belt.Under those conditions that mentioned above,the windrowing quality could meet the requirements.(4)Motion law of stem in windrowing process was researched.Using the method of planar rigid body displacement matrix,trajectory equation of each point of the rape stem was got in the reel wheel rape stem action stage.Analysis of the force and speed,width compression and compression wave velocity of rape stem,the relationship between the degree of compression density and growing density was gived,the relationship between the compression wave propagation velocity and the forward velocity of the machine was got.Kinematics and dynamics of the action process of horizontal toggle mechanism and vertical toggle mechanism were studied.Conditions that rape stem on the conveyer belt could be transported to exhaust straw port with the same speed of the conveyer belt was gived.Using the method of field stem staining,rape stem transporting and windrowing process was studied.Rape stem took on hierarchical state on the conveyor belt,Spike amplitude difference was closely related to Spike amplitude difference of the windrowing stem.during the conveying process,the stem rotated a certain angle,rape stem turned to land from the conveyor belt.The lag properties of the rape windrowing process was studied.Rule that feeding in speed of windrower was changed into stem output of exhaust straw port was gived.(5)In order to reduce windrowing angle,windrowing angle difference,lossing percent,the structural configuration,structure parameters and motion parameters of the windrower were optimized.Through the single factor experiment,factor that influenced windrowing angle,windrowing angle difference,lossing percent were classified.The test results show that factors influencing the windrow quality mainly included assemble angle of transportation device,the forward speed of the machine,reel speed,the speed of the conveyor belt.The quadratic polynomial regression models of windrowing angle,windrowing angle difference,lossing percent of factor parameters were obtained by Response Surface Method.The significance test was conduced,the importance order of factors were determined.The influence law of single factor effect and double factors effect was analyzed.The optimal parameters were:assemble angle of transportation device was 15.53°,the forward speed of the machine was 0.65m/s,reel speed was 15 r/min,the speed of the conveyor belt was 15 r/min.The optimal determination standard were:windrowing angle was 26.33°,windrowing angle difference was 22.825°,lossing percent was 0.53%.4SY-2.0 rape windrower was parameter optimization designed,windrow quality index was measuredby experiment,windrowing angle was 27.45°,windrowing angle difference was 23.16°,lossing percent was 0.61%.Index of test accorded with the given index of optimization test.4SY-2.0 rape windrower was detected.windrow quality index was as fellow:windrowing angle was 32.56°,windrowing angle difference was 21.68°,lossing percent was 0.65%.,it could meet the requirement of rape partition harvest successor operation. |
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