Optimization Design' And Research Of Key Parts Of Vertical-Shaft Banana Stalks Chopper

China is the banana production and consumption power, With the expansion of the domestic banana planting area, the processing of abandoned banana stalks has become a big problem faced by the industry of our country. For the present, the method of processing banana stalks is still in a traditional way in most of domestic area, after the banana straws is cut down by workers we are used to burning or accumulating it, these processing methods are low efficient and also cause an environmental pollution and soil degradation of the planting land.The technology of Banana stalks crushing and returning to the land can solve these problems, by using the machine to work instead of human labor can improve the efficiency of processing of banana stalks and lower the labor intensity. Moreover, due to the banana stalk is rich in organic matter and trace elements, the crushing and returning of the stalks can help to improve the soil structure and increase organic matter content in the soil. For the present, due to the lack of research unit, the R&D of banana stalks chopper falls behind, all crushing machines are obsolete and have a poor performance. To solve this problem, by using the analytical method theoretical analysis, finite element emulation analysis and orthogonal experiment analysis, the banana stalks chopper produced by Hainan University will be optimized based on two main parts of the machine, they are the frame case and crushing device, in addition, a overload clutch will be design for protect the parts of machine. The optimized contents are as follow:(1) Optimal design of frame chassis. To begin with, narrowing the width of frame case to reduce the power consumption of the chopper, meanwhile, for the convenience of the repair and maintenance of the crushing blade, add a rectangular skylight on the top of the case. Then, making the modal analysis and sensitivity analysis for the modified case,calculated its first six modal frequencies, corresponding vibration mode, and the modal frequency sensitivity of each part of the case plate thickness. Based on the parameters of simulation, the optimization design for each part of steel plate thickness of frame case and machine suspension device was carried out. The results of optimization design showed that the first- order modal frequency of frame case is increased by 28%, its weight is reduced by 9%, the frequency keeps away from the resonant frequency, and not only that, we realize the lightweight design purpose of case.(2) Optimal design of crushing device. Firstly, two types of failure form fracture and non-fracture of L-shape crushing blade was analyzed in a theoretical way. Followed by the optimization design for the parameters of the crushing blade such as structure, material,thickness, new crushing device is composed of the straight knife and its bended adapter,65Mn spring alloy is selected as the material of the knife,a layer of abrasion-resistant alloy is welded to the knife edge for the abrasive resistance, the thickness of the blade is 12mm.In the last step, a stop block is set to 45°angle deviation from the center line of the blade adapter, in order to solve the problem of higher power consumption caused by the increased deflection angle. In addition, the factor as crushing efficiency should be consider,the speed of vertical knife shaft is not lower than 1070 r/min.(3) In order to prevent overload during the smash operation of the crushing chopper,two types of overload protector are designed: (1) shear pin overload protection (2) friction clutch overload protection. Taking full account of the cost and manufacturability of the factory, we decide to choose the shear pin overload protection as the overload protection of chopper. In addition, the walk device is optimized, by using the rolling wheel instead of the original one can reduce the power consumption of the chopper.(4) The banana chopper test is carried out by using the orthogonal experiment which includes 3 factors and 3 levels. The experimental results show that factors affecting the effects of crushing chopper, in accordance with influence degree, could be ranked as blade thickness >knife shaft speed> machine speed. When the machine speed reaches 3 km/h,knife shaft speed 2000 r/min, blade thickness is 12mm, the quality of smashing and ground coverage can achieve a better effect, therefore, the blade thickness can be design to 12mm.