| The jujube tree is a jujube plant belonging to the buckthorn family produced in China.It is one of the important forest and fruit crops in the Xinjiang.At present,Xinjiang red dates are basically harvested manually,which has the problems of high labor intensity and low harvest efficiency.The harvest cost reaches an average of 0.8 yuan per kilogram.The harvest period of Xinjiang red dates coincides with other crops that require manual harvest,making it difficult to hire enough in a short time Labor,red dates can not be harvested in time,the loss is obvious.This paper mainly combines the planting model of Xinjiang jujube trees and the physical characteristics of Xinjiang jujube,and puts forward the design plan,selects the appropriate plan to design and manufacture an air-suction red jujube picker,and conducts field test research on it.The main research contents and research results are as follows:First of all,to study the factors affecting the pneumatic harvest of red jujube.The field investigation of Xinjiang jujube garden was mainly carried out,and the triaxial dimensions,density and water content of red jujube during the harvest period were measured,and the suspension and friction characteristics of the red jujube were tested.The air velocity of at least 24m/s is required to obtain the air-absorbed red dates through the test;the maximum friction angle between the red dates and the steel plate is about 40°.Secondly,design test and simulation of cyclone separation type red date picking test bench.According to the principle of jet flow and cyclone separation,the jujube picking test bench is designed,and the fluid analysis software is used to simulate the fluid in the test bench to obtain the same air flow state as the design plan;make the physical object and perform the verification test.Thirdly,three design schemes are proposed and a more reasonable design of air-suction red date picking machine is selected.The air suction type jujube picking machine is mainly composed of picking device,impurity removing device,unloader,centrifugal fan,diesel engine,sieve plate,walking device and other parts.Through the study of the mechanical structure and principle of pneumatic harvesting red dates,the method of gravity settlement is used as the design idea of the settlement device,the structural dimensions of each key component are obtained through calculation and other methods,and the three-dimensional model is drawn using Solidworks2015 software and the optimization between each part is optimized The layout,the selection of suitable fans,diesel engines,drive axles and unloaders,complete the design of the whole machine.Finally,according to the three-dimensional model of the air-suction red date picking machine,a prototype was made and the field pneumatic harvesting of red dates was conducted.A single factor test was carried out with the wind speed at the inlet of the jujube as the variable and the picking rate,impurity rate,breakage rate,and operating efficiency of the red jujube harvest as the test indicators.The test results show that the appropriate increase in the air speed of the air suction pipe can improve the cleanup rate,impurity rate and harvesting efficiency of the prototype;the air speed change of the air suction pipe has no significant effect on the mechanical damage of jujube.According to the field test,the results of the operation performance of the air-suction red date picking machine are:average pick-up rate 97.18%,average impurity rate 2.48%,average breakage rate 2.46%,working efficiency 229.20m2/h.The working state of the prototype is stable,and the field red jujube harvesting operation can be carried out for a long time. |
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