| Hilling plays an important role in crop tillage which has the advantages of loose soil,water storage,moisture conservation,promoting the growth of crop roots,removing weeds and preventing wind from lodging.However,the traditional hilling machine cannot adapt to the high-hilling and has poor ability to throw soil.The soil is hardly to be formed and the seedlings could be injured during the operation of traditional hilling machine.This paper developed a new type of hilling machine with obliquely placed spiral combining with the relevant agronomy requirements of mechanical hillling and analyzed the key components to solve the problems of traditional machine after reading a large number of papers on hilling machine.The main contents of this paper are as the following shows that:The 3D model of the hilling machine is established according to the requirements of agronomy and the ideas of innovation.The machine is composed of hydraulic mechanism,machine frame,row spacing adjusting device,depth limiting mechanism,leaf protecting device,device for distributing soil and spiral hilling cutter,etc.The key components of the machine are designed and introduced.This paper designed a hilling machine with obliquely placed spiral and simulated the milling effect of spiral milling cutter on the work piece,carries on oblique milling to the soil,and controls the flowing direction of the soil cooperated with soil dividing device.The diagram of the first six order structure vibration pattern and the corresponding modal frequency and vibration characteristics of frame of hilling machine have been obtained by means of establishing model of the hilling machine and analysing it using finite element method.The results show that external excitation frequency is only 40 Hz which is much smaller than the first six order modal frequencies(96.32~209.45Hz).The external vibration will not resonate with the vibration of the frame itself in normal operation.This paper analyzed the mechanism of spiral cutter,the key component of hilling machine,and obtained the working mode of the spiral cutter.Furthermore,the analysis of motion of the spiral cutter is carried out using the ADAMAS software,and determined the direction of the self-rotation and the spiral blade rotation on the two sides of the single hilling unit.In other words,the soil can be transported upward to throw the soil and on the side of the ridge could be fully cut and broken by the spiral blade at the same time when the left hilling blade chooses the mode of forward and right rotation,the right hilling blade chooses the mode of reverseal and left rotation.Orthogonal experiment on the three factors: the speed of the hilling machine,rotating speed of the axis of the hilling blade and the blade intercept which mainly affect the work for the analysis of mode(the forward and right rotation)of the spiral blade.The result shows that the speed of the hilling machine and the blade intercept have a significant effect on the operation but the speed of the hilling machine is the most important factor.In addition the novel hilling machine can get a higher soil breaking rate,good shaping effect and extirpate weed while taking into account the banking efficiency at the same time with the movement speed of 2.52km/h and spiral blade rotation speed of 300r/min.On the basis of 3D model of the hilling machine,the prototype was produced and the field experiment was carried out in the experimental field of Xuchang Tobacco Research Institute,Xuchang City.The test results show that the rate of broken soil,the slope of soil,the thickness of soil,the height of soil and the upper width of ridge can meet the related agronomic requirements and the hilling machine has high working efficiency and performance. |
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