| Rape is the oil crop with the largest operating area in our country.Mechanized harvesting of rapeseed is one of the keys to improve production efficiency and promote the development of rapeseed industry.Staged harvesting is a harvesting method which makes full use of the post-ripening characteristics of rapeseed and has the advantages of consistent grain maturity and low harvest loss rate.The high cost and lack of special equipment restrict the popularization and application of windrowing technology.Combined with the advantages of large number of crawler harvesters in our country,and taking into account the requirements of road transportation,a wide foldable rape windrower based on crawler power chassis was designed.The table can be interchanged with the combine harvester header,reducing the input cost of mechanized production and improving the power utilization rate of the equipment.Based on the two major technical points of wide-width operation and narrow-width transportation,as well as the windrowing process of double-sided strip laying and drying on the stubble,the rape windrower was designed as a whole,the operating parameters of each working part were determined,and the frame structure was carried out.The topology was optimized,and the operation effect of the machine tool was analyzed through field experiments.The main work contents are as follows:(1)The material characteristics of different rapeseed varieties at the suitable harvest period were tested and analyzed.A device for measuring the center of gravity of rape plants was designed by using a gravity sensor.The relative error between the calibration results and the traditional measurement results is less than 3%.Six kinds of rapeseed,including Huayouza 62,Ningyouza 1838,Qingyouza 3,Yuyou 28,Zheyou 108 and Zhongyouza 19,are the research objects,and the geometric characteristics,mechanical characteristics and water content of each variety of rapeseed were tested and analyzed.The average plant height of rapeseed is between 1659.6～1949.5mm,the height of the first branch is between491.6～829.6mm,the height of the center of gravity is between 922.3 and 1086.5mm,and with the increase of the stubble height,the height of the center of gravity of different varieties of rapeseed shows a linear growth trend.The mechanical properties of different varieties are not significantly different,the average maximum destructive force is between82.45～203.02N,the average value of bending strength is between 3.11～8.38MPa,the average value of maximum bending displacement ratio is between 0.36～0.56,the average value of moisture content of different varieties of rape is between 71%～88%,As the harvest time moved later,the water content of the plant showed a trend of rising slowly at first and then falling;The relationship model includes various indicators of rape,including the height of the plant of the rape,the height of the first branch,the number of branches,the center of gravity of the plant and the moisture content was determined by regression analysis when the stubble height is 300mm.Provides a basis for height adjustment.(2)The design of the wide foldable rape windrower and its key components was carried out.Based on the systematic analysis of the key technologies of rapeseed swathing and wide-width folding at home and abroad,the design scheme of the wide-width foldable rapeseed windrower was proposed.Windrower structure,transmission route and operating parameters,the working width of the machine is 4.0 meters,and the forward speed is0.8～1.1m/s;a hydraulic folding device was designed by using the hydraulic cylinder and the guide rail-slider mechanism,and developed Hydraulic system design and analysis,by calculating the operating power of each component and analyzing the force of the header,many parameters were determined,such as the model of hydraulic motor and hydraulic cylinder,the motor model is BMR80,the displacement is 81.5ml/r,the hydraulic cylinder model is HSG-40,and the strokes are 200mm,500mm,700mm,and 150mm respectively;The design of the cutting device,the reeling device,the conveying device and the harvesting device were carried out.By analyzing the rotational speed of the reel,conveying device and cutter,they are 42.5r/min,260r/min and 390r/min;the site of this center of gravity of the windrower was determined by analyzing the longitudinal stability of the windrower,and this could ensure its longitudinal stability.The utilization coefficient is0.183,which meets the mass distribution requirements of the crawler chassis.(3)Based on ANSYS software,static analysis and topology optimization design of windrower frame were carried out.The statics module was used to analyze the force of the header frame and the hydraulic folding device frame when the header is unfolded and folded,and based on the results,the topology optimization design of the two frames obtained when the proportion of material removal is 85%and 80%.respectively,reasonable topological results were obtained;the stress and deformation of the two frames before and after the optimization were compared and analyzed.After optimization,the maximum stress of the header frame is 149.14MPa,and the maximum strain is 5.26mm,which are reduced by 28.4%and 18.3%respectively,the maximum stress of the hydraulic folding device frame is 66.83MPa and the maximum strain is 0.14mm,which are reduced 67.9%and 53.3%respectively,and the mechanical properties of the frame have been greatly improved after optimization.The first six natural frequencies of the header frame are28.19Hz,32.63Hz,49.61Hz,95.96Hz,120.14Hz,136.81Hz,Similarly,the hydraulic folding device frame are 98.82Hz,124.88Hz,148.18Hz,179.58Hz,196.17Hz,219.50Hz,which are far away from the excitation frequency limit range of the windrower working parts.(4)A field trial of wide-width foldable rape windrower was carried out.Taking Huayouza 62,which was broadcast by machine as the test object,the basic parameters of rapeseed in the experimental field were measured by the five-point sampling method.The average plant height of the rapeseed in the test area is 1560 mm,and the planting density is25 plants/m~2;The laying quality,the laying angle is 24.4°,the laying angle difference is8.52°,the laying width is 617.7mm,the laying height is 512mm,and the stubble height is362.9mm,all indicators meet the quality standards of the windrower operation. |
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