| It is beneficial for fruit trees to ditch and then apply fertilizer in hill orchard.We have to dig ditches before we can apply fertilizer.The ditchers we can buy has many disadvantages,for example consume a lot of energy,ditch size is inconsistent,ditching blade is easy to break,unable to adapt to multiple environments and so on.Ditching blade is very important for ditcher.Ditching blade will touch the soil and cutting soil.Therefore,the strength and wear resistance of the ditching blade will be better.In particular,hill orchards are widely distributed in China.The characteristics of the soil are different.It's hard for us to design ditching blades.We have designed ditching blades,which can be used in the spiral ditcher of hill orchard developed by our research group.We have completed the simulation experiment,and we have changed the structural dimension data of the toothed blade.In order to reduce the power consumption of ditcher,we designed bionic ditching blades.We have treated the ditching blades with wear-resistant technology.There are a lot of stones in many hill orchards.We have designed carbide ditching blades.We have explored the method of surfacing that can be used on large area.Our research can provide reference for the design of ditching blades.The specific research contents are as follows.?1?We learned about the management of the orchard throughout the country.We measured the performance data of soil and rocks in the orchard.The roots of citrus trees are in hemispherical space of 0-1.2m in diameter and 0-0.9m in depth.Diameter of root is mainly 1-28mm.The type of soil is sandy clay,and the type of rock is shale,mudstone,limestone,sandstone and dolomite.Diameter of rock particles is 20-100mm.The distribution of rocks is irregular in hill orchard.Hardness of rock is between soft and medium hard.Types of ditching blades:straight blade,curved blade and toothed blade.The edge angle of the ditching blade is 30°,the installation angle is 10°,the bending angle is 45°,and the cutting angle is 40°.The edge line of curved blade is a sine exponential curve,the initial sliding angle is 65°,and the ratio coefficient between the increment of sliding angle and polar angle is-0.1.The teeth of the toothed blade are pyramid shaped,the width of the back part is 8 mm,the height is 6 mm,the total length is 13 mm,and the arc radius of the front part is 3.124mm.The shape of the insert blade is a plane triangle.In the field experiment,we compared the performance of three kinds of blades.There is a significant difference between ditching power consumption of curved blade and straight blade.When the ditch depth is 150,200,250,300 and 350 mm,the ditching power consumption of straight blade cutter is 19.28%and 19.62%,10.60%and12.24%,17.54%and 18.26%,14.04%and 16.13%,9.60%and 9.88%higher than that of curved blade and tooth blade.There was no significant difference in the ditch depth stability coefficient among the three kinds of blades.All aspects of the toothed blade are optimal.?2?We build a EDEM simulation model and optimized the model with the stacking angle as a reference.The influence on ditching power consumption is from bending angle>edge angle>installation angle>tooth shape.We found a set of optimal values,the installation angle is 4.5°,the bending angle is 49°,the edge angle is 21°,the tooth shape is 1.25 times,and the ditching power consumption is 9.73kw.We have completed the field experiment,and the ditching power consumption is 9.87%higher than the simulation value.This shows that the error of simulation model is not very large.The ditching power consumption is reduced by 12.80%.The influence degree of ditching power consumption is from ditch depth>forward speed>ditch speed.?3?We use reverse engineering technology to change the structure of the toothed blade.Our bionic object is the third toe of the mole's forepaw.When the ditch depth is150,200,250,300 and 350 mm,the ditching power consumption of the bionic blade is9.68%,10.44%,10.22%,10.70%and 10.95%lower than that of the tooth blade.We have completed the simulation experiment and bench experiment of a single tooth.The resistance of the bionic blade is less than that of the toothed blade.When the soil humidity is higher,the resistance reduction value of the bionic blade is also higher.The results of field experiments show that the ditching power consumption of III and V bionics blade is 11.164%and 5.156%lower than that of tooth blade.?4?We used five kinds of wear-resistant technology to treat the ditching blade,and compared the wear-resistant performance of them.The results of bench experiment show that the wear quality of?,?,?and?blade is 14.17%,42.05%,66.98%and75.96%lower than that of?blade.The microstructure of?blade is fine acicular tempered martensite,a small amount of retained austenite and a small amount of granular carbide.The microstructure of?blade is fine acicular martensite,tempered martensite,very little retained austenite and granular carbide.The microstructure of?blade is fine acicular high carbon martensite,high carbon tempered martensite,a small amount of retained austenite and granular carbide.The microstructure of type?and?blade is a small amount of austenite and dendrite.The average microhardness value of I-V blades are 558,700,888,1195 and 1441 HV0.1.The friction coefficient of I and II blades are0.67 and 0.57,and the wear type is adhesive wear.The friction coefficients of?,?and?blades are 0.26,0.25 and 0.22,and the wear type is abrasive wear.After 10hours of field operation,the wear quality of?and?blades was 28.26%and 82.63%lower than that of tooth blade.?5?The cemented carbide blade is designed.We have completed the bench experiment,and found that the impact resistance and wear resistance of the cemented carbide blade are higher than that of the tooth blade.After the tooth of cemented carbide blade breaks and wears,we can use brazing to repair it.When we wear the blades on the bench for 60 minutes,the wear quality of the cemented carbide blade is 22.54%lower than that of the toothed blade.We have designed five different types of surfacing,they are adjacent normal,adjacent tangent,interval normal,interval tangent,interval mesh.It is found that the adjacent normal direction has best performance on impact resistance and wear resistance,and the interval tangential direction has the worst performance,with a difference of 3.02 times.When the density of the welding path increases and the direction is normal,the test performance of impact resistance and wear resistance is better.The adaptability and economy of interval mesh's method are better. |
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