| As a large agricultural country,China produces an astonishing amount of biomass straw,which can reach 600-700 million tons every year.Most straw treatment methods are directly returned to the field or burned on the spot,which cannot be used efficiently and will cause damage to the environment.In order to realize the efficient collection and utilization of straw,this project aims to develop a mobile straw pelletizer as a straw field processing and harvesting equipment.The mobile straw pelletizer developed in this subject integrates the picking and cutting,crushing,granulation and collection of crop straws,which can greatly reduce the storage,handling and reprocessing of straws and other related processes,and save costs.By consulting related literature and analyzing the main characteristics of related equipment at home and abroad,it provides a reference for the design of this machine.Using theoretical analysis,design calculations,computer-aided analysis,and field trials combined research methods,the research and development of a mobile straw pelletizer was finally completed,and prototype trial production and field trials were carried out.The main research contents of this paper are as follows:(1)Clarify the overall design requirements of the mobile straw pelletizer and design the overall scheme.The Dongfanghong LX1004 wheeled tractor is selected as the power source of the whole machine.In combination with actual production requirements,design and research the key components of the whole machine such as the picking and cutting device,the crushing device,the conveying system,and the granulating device.Analyze the characteristics and advantages and disadvantages of different designs of the main structure of each key component,and design and choose the structure suitable for this machine.Finally,determine the working principle of the whole machine and the power transmission route of the whole machine.(2)The structure of several key working parts of the mobile straw pelletizer is designed in detail.In the design of the pick-up and cutting device,a hammer-claw pick-up device is used in conjunction with the moving knife of the roller.This can efficiently cut the straw twice and is a new type of cutting and feeding system;For the crushing device,the design of the crushing device was determined from factors such as the gap between the hammer and the screen,the diameter of the screen hole,and the end speed of the hammer;The conveyor system design chooses a scraper conveyor,which is more suitable for the transportation of the straw;The granulation device considered several common granulation processes,and finally the design selected the moving roller flat mode structure,which is more in line with the working environment and process requirements of this equipment.(3)Use analysis software ANSYS Workbench15.0 to perform finite element analysis on key components.The static analysis of the hammer claw in the pick-up cutting device is carried out,and the structural design is verified to meet the production requirement from the deformation analysis;The force analysis of the hammer frame plate in the crushing device shows that the middle hammer frame plate bears the greatest force.And carry out statics analysis on the middle hammer frame plate,from the two aspects of equivalent stress and total deformation,to ensure the strength of its structure;In order to analyze the vibration frequency characteristics of the main shaft of the granulation device,the first six modes of the vibration mode are analyzed.Through the analysis of natural frequency and excitation frequency,it is ensured that the equipment will not resonate during operation.(4)Prototype trial production and test of the key components of the mobile straw pelletizer.According to the relevant design standards,straw crushing qualified rate and straw particle density as the evaluation criteria,and field experiments are carried out.Evaluated the working performance of the crushing device and the granulating device,verify whether the prototype meets the design requirements,and verify the effect of straw crushing and straw pelleting.The mobile straw pelletizer designed in this subject can effectively solve the problem of straw processing in the field,improve the recycling rate of straw,save resources,and conform to the national sustainable development strategy. |
