Optimal Design And Experiment Of Wedge Dragreduction Rotary Blade

The cultivation resistance is large and the high power consumption has become the key problem of the rotary tiller.Statistics show that about 90% of the resistance of the rotary tiller comes from its key component—the rotary blade.Therefore,designs a kind of wedge drag reduction rotary blade to explore its microcosmic mechanism of reducing resistancereducing consumption.The strength of rotary blade is tested and optimized with cutting resistance and power as the evaluation index;and the optimum working parameters are determined by the optimization of the structure of the wedge drag reduction rotary blade.The main contents and conclusions are as follows:(1)Structural design of wedge drag reduction rotary blade.Based on the cutting mechanical model,a kind of wedge drag reduction rotary blade was designed,and the force of any cross section between the cutting edge of the rotary blade and wedge drag reduction rotary blade was analyzed.It is obtained that the cutting resistance of the wedge drag reduction rotary blade is lower than the cutting resistance of the rotary blade.According to the theoretical analysis,the bending angle,the cutting height and the bending radius of the wedge drag reduction rotary blade are selected,and the power consumption model is established.(2)Static strength analysis.A static simulation of the rotary blade and the wedge drag reduction rotary blade was carried out by using the software of HyperMesh-Abaques,and the strength optimization of the rotary blade was carried out on the basis of the simulation results.The results show that the maximum stress of the rotary blade is 348.7 MPa,and the maximum stress of the wedge drag reduction rotary blade is 308.8 MPa.The maximum stress of the two types of rotary blades(materials 60Si2Mn)is within the yield strength of the tool materials 1000 MPa.(3)Dynamic analysis,simulation and optimization of rotary blade.A dynamic cutting model of the "rotary blade-soil" was constructed using the Drucker-Prager criterion to analyze the microcosmic process of the rotary blade cutting soil,with cutting resistance and milling as the index.Optimization of the structure and working parameters of the wedge drag reduction rotary blade.The results show that during the rotary operation,the stress of the reduction of rotary blade increases with time and the increase of the soil area in contact with the rotary blade.When the stress reaches a maximum value of 247.3 MPa,it is much less than the yield strength of the tool material;the bending angle of the wedge drag reduction rotary blade is 122.5°,the cutting height is 51.4 mm,the bending radius is 28.5 mm,the forward speed is 4.10 km/h and rotary speed is 300 r/min,the cutting resistance and power consumption of the wedge drag reduction rotary blade are optimized to the optimal value;the average cutting resistance is 8.81 % lower than that of the rotary blade,and the average power consumption is 8.56 % lower than that of the rotary blade.(4)Analysis of filed experiments.Based on the evaluation indexes of torque,power consumption and breaking rate of soil,the forward speed of the tractor was changed,and the filed experiments was carried out on the rotary blade and the wedge drag reduction rotary blade.The results show that under the optimum working parameters,the power consumption of optimized the wedge drag reduction rotary blade and the rotary blade is the same as the simulation test,and the error of the average power consumption(0.07 %)to the extent permitted;the effect of forward speed on power consumption and soil quality is significant.In a given working situation,the torque of the wedge drag reduction rotary blade is better than that the rotary blade,and its average torque is 7.65 % lower than that the rotary blade,average power consumption is 7.87 % lower than that the rotary blade.And the rate of fragmentation increased by 4.23 %.The wear resistance of the rotary blade is equal to that of the national standard.It can not only reduce the power consumption,but also improve the rotary quality and ensure the service life of the rotary blade.