Design And Test Of Deep Loosening Machine

China is a big agricultural country.For a long time,the farming mode of agriculture is the traditional mode of farming.This leads to the deterioration of the soil structure on the surface of the cultivated land and the nutrients in the soil.In addition,the use of chemical fertilizers and pesticides has caused serious pollution to the soil.This leads to the destruction of the living environment of the crops,restraining the growth of crop yield and causing the phenomenon of "increasing fertilizer and not increasing production".Therefore,it is very important to improve the soil structure and enhance the self recovery ability of soil.Based on the analysis of the development and research status of deep loosening machines at domestic and foreign,it is found that most type of the existing deep loosening machines are Side knife type,Plough type and Shovel type.The operation types of these deep loosening machines are damaging the soil plough layer based on not destroying the soil structure to enhance the water holding capacity of soil.At present,the deep loosening operation in the southern areas,such as woodland and mountain areas,requires a more refined soil fragmentation at a depth of less than 20 centimeters.The existing deep loosening machines can't meet the job requirements,and the depth of cultivated soil of the existing horizontal rotary cultivator is less than 10 centimeters.Therefore,it is necessary to design a kind of deep loosening machine which can meet requirement of the areas of the south,such as mountain,woodland and so on.In view of this demand,a kind of deep loosening machine is designed on the basis of the study of the physical characteristics of the operating object.In this paper,the deep loosening machine is the research object,and the contents and conclusions are as follows:(1)Taking the soil of three kinds of working environment in mountainous area,woodland and grassland as objects,the weight,moisture content and hardness of the working objects were measured respectively,and the physical characteristics and their changing rules of the working objects were found out.(2)According to the soil physical properties measured,the structure of the key components of the deep loosening equipment are designed and the introduction of the structure and working principle of deep loosening equipment,the parameter calculation and mechanism analysis of the deep loosening soil tools,the working parameters of deep loosening equipment are obtained.(3)The kinematic analysis of the cutting tool was carried out,the kinematic equation of the tool was obtained,and the working conditions of the cutting tool were found.Through the comprehensive analysis of the influence of different rotary speed ratio on deep loosening effect,blade stress and soil cutting power consumption,the optimal rotation ratio of tool operation is determined to be 12,and the force curve of single blade of deep loosening tool in a single cutting cycle is obtained.(4)A finite element model of linear statics analysis for deep loosening cutters is established.By solving the finite element model,it is found that the maximum stress and the minimum safety factor appear at the welding place of the top of the spiral blade and the deep loose cutter shaft.The maximum stress is 31.756MPa.The minimum safety factor is 7.8725.The maximum deformation occurs at the cutter head of the deep loosening tool,which is 0.061655mm.The fatigue characteristics of deep loosening cutters are analyzed.It is found that the dangerous area of the cutting tool is located at the welding place of the tip of the spiral blade and the deep loose cutter shaft.When deep loosening operation is carried out under normal working conditions within 3 times,the tool can achieve 5000000 cycles of design life,no cracks,and the minimum safety factor of the tool is greater than 1,and the tool reliability is relatively high.With the aggravation of overloading,the tool life rapidly decreases,the fatigue damage degree of the tool increases gradually,the fatigue safety factor is less than 1,and the reliability of the tool is reduced.The modal analysis of the frame of the deep loosening machine is carried out,and the first six natural frequencies of the frame are found out,and the corresponding vibration modes are obtained.(5)The feasibility test of deep loosening machine has been carried out.It is found that the deep loosening machine can run smoothly,and it has the ability of automatically adjusting the depth of soil for different terrain,and it can meet the needs of normal deep loosening.The performance test of deep loosening machine is carried out.It is found that the loosening depth of deep loosening machine can reach more than 200mm,which is in line with the requirement of deep deep loosening and the design requirement of deep loosening machine.By random sampling in the direction of the sample and statistics not broken clods accounted for evaluation of the effect of deep loosening tool,found no big clods of unbroken forest,followed by grassland,mountain without breaking up soil accounted for the largest.The verification test of deep loosening machinery efficiency is carried out,and the test results are comprehensively scored.The maximum feasible operation efficiency of deep loosening machinery under different operation environments is found,namely,woodland 1758m2/h,grassland 1758m2/h and mountain 1080m2/h.