| In recent years,China’s chilli cultivation area and annual production of chillies have continued to expand,with China now ranking first in the world in terms of chilli cultivation area.The demand for chillies and their processed products in the international market is also growing,making chillies an increasingly important strategic position in China’s red industrial industry.According to statistics,in 2021,nearly 28 provinces and regions in China are growing chillies,with a chilli cultivation area of 2 million hectares and a chilli production of 40 million tonnes,of which the southern region has a chilli cultivation area of 545,000 hectares and a production of 7.21 million tonnes.However,most of the pepper planting areas in the south belong to hilly areas,and the blocks are not conducive to large machinery operations.To address this situation,in order to solve the problem of mechanised pepper harvesting in hilly and mountainous areas,inter-set operations and other plots,reduce operational links and labour consumption,and improve the mechanisation level and production efficiency of pepper harvesting,a fully hydraulic driven hydraulic system was designed for the pepper harvester by analysing the working requirements of a small crawler-type pepper harvester in harvesting peppers and analysing the transmission of key components of the harvester.By studying the literature on hydraulic systems and chilli harvesters of agricultural machinery at home and abroad,combined with field research,and by understanding the cropping pattern of chillies and the problems that exist when harvesting chillies,this thesis determines the content and direction of scientific research,and the main scientific research content and results are as follows.(1)Firstly,the structure of the crawler type small harvester was modelled in three dimensions by solidworks software,and according to the actual working conditions of each operating unit of the pepper harvester,the speed regulation method and circuit scheme of the hydraulic system were determined.On the basis of the analysis of the working conditions and the requirements of pepper harvesting,the hydraulic system combined with the mechanical equipment,for the walking system,picking conveying system,picking device lifting system and bin turning The hydraulic system design scheme was proposed and the corresponding hydraulic system was designed,the form of the hydraulic system and power transmission were determined,the hydraulic system diagram of the harvester was drawn by CAD.(2)By establishing a mathematical model for each operating unit of the pepper harvester and carrying out load analysis on the corresponding components of the hydraulic system of the pepper harvester,the basic parameters of the hydraulic cylinders,motors and pump in the system were calculated and the model types were determined,and the calculation and selection of oil pipes,oil tanks and valve components were carried out.(3)A simulation model was established using AMESim on the basis of the spicy hydraulic schematic diagram.The model of the hydraulic cylinder,hydraulic motor and the corresponding load was established using AMESim software,and a comprehensive simulation calculation was carried out for the executive components of each sub-hydraulic system respectively.(4)The prototype crawler-type small pepper harvester required for the test was completed and hydraulic performance tests were carried out on the performance of the hydraulic system,testing the speed of the hydraulic motor,the expansion and contraction speed and displacement changes of the hydraulic cylinder.In order to verify the influence of the hydraulic system of the crawler-type small pepper harvester on the operational performance,the pepper harvester was tested by using the net harvesting rate,breakage rate and loss rate of pepper as the test indicators.The results show that: when the pepper harvester walking hydraulic motor speed is 93r/min and the picking drum hydraulic motor speed is 188r/min,the breakage rate is 2.3%,the loss rate is 6.1% and the net picking rate is 95.8%,the picking quality is in line with the technical indicators,the pepper harvester walking hydraulic motor and the picking drum hydraulic motor test indicators meet the technical requirements,which verifies the design of the pepper harvester The reasonableness of the designed hydraulic system. |
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