| Moso bamboo is the most widely planted and economically valuable bamboo species in China,playing an important role in ecology,construction,art,and production.However,the bamboo stumps left after harvesting take 8-10 years to decompose naturally,occupying a large amount of land in the bamboo forest for a long time and seriously affecting the regeneration speed of Moso bamboo.This has become an urgent problem that needs to be solved.Through investigation,it was found that there is currently no mature bamboo stump excavator available on the market.In order to solve the problem of bamboo stump occupation,this thesis designs a new type of bamboo stump excavator,with the following main research content:(1)a test platform was built to study the rotary cutting mechanism and performance of bamboo rhizomes.This includes establishing a mechanical model for bamboo rhizome cutting force,analyzing the tool’s force situation theoretically,studying the factors affecting the rotary cutting performance,and introducing the rotary cutting resistance coefficient K to derive the cutting resistance calculation formula.A rotary cutting tool performance testing platform was designed to conduct single-factor experiments,using the rotary cutting resistance coefficient as the indicator to verify the effects of rotary cutting speed,diameter,and pitch on rotary cutting performance.The Box-Behnken central combination test method was then used to fit the original data,analyze the interactive effects of rotary cutting diameter,speed,and pitch on the resistance coefficient K,and determine that pitch has the greatest effect on the rotary cutting resistance coefficient,followed by rotary cutting diameter and speed.(2)Solidworks software was used to model and design the bamboo stump excavator,including the mobile working frame,transmission mechanism,inner diameter centering mechanism,rotary cutting cylinder,and reducer housing.The critical soil discharge conditions of the spiral mud guiding plate and rotary cutting cylinder were determined by theoretical analysis,and the strength of the cutter cylinder was checked.A mathematical model was established,and the MATLAB software was used to optimize the transmission system,reducing the center distance of the secondary gear reducer system by 47.97%,greatly reducing the overall size.An inner diameter centering mechanism was designed that could be used for different diameters within the range of Moso bamboo breast diameter.(3)simulation analysis and optimization design were conducted on key components.After verifying the safety of the machine’s execution mechanism using finite element simulation software ANSYS,a prototype of the rotary cutting cylinder was processed for bamboo stump excavation testing.Based on the problems encountered during the testing,the rotary cutting cylinder was further optimized by selecting a new power source,optimizing the tool thickness,improving the tool fixing method,reducing the distance between cutting and soil discharge,and adding an auxiliary soil discharge wedge.These optimization measures greatly improved the success rate and speed of bamboo stump excavation.The secondary reduction system was optimized to adapt to the improved power source,and the statics and modal analysis and optimization design were carried out on the reducer housing,reducing the overall weight by28.5%.The bamboo stump excavator studied in this thesis can complete excavation work in less than 2 minutes,greatly improving efficiency compared to traditional manual excavation or other methods.In addition,this equipment provides technical reserves for the mechanization and automation of bamboo stump excavation. |
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