| Pecan has become a popular upscale nut and gets the wide recognition of consumers,because of its high value of nutrition and unique taste.The increasing market requirement ask for more mechanization product method for the whole walnut processing industry,but the shell-breaking equipment still has problems currently.As for extrusion crack and centrifugal shell-break method is adopted as the main strategies for pecan shell-break equipment.But the low production rate is hard to be improved.Meanwhile,the bad processing quality will affect the further processing which restrict the develop of the pecan processing industry.To solve such problems,this study propose an bionic-impact method,which imitate the artificial processing to shelling pecan,and developed an bionic-impact pecan shell breaker.Design and experiments are both mainly focused on the structure and parameters of the shell breaker.The paper described the overall structure of prototype and introduced the technical parameters of shell breaker,the three-dimensional model was built by Pro/E software.In this study,cell feed wheel was designed to translate pecan into feed pipe from hopper one by one like water flow,and thus method could avoid pecans plugging the feed pipe.The bottom of pipe linked shelling system,Which is one of the most important part during the study.In order to figure out a more efficiency shelling method,a bionic-impact structure have been designed,based on the particle properties and mechanical behavior for pecan rupturing under impact loading,mathematical model of designing the shelling system was built.The system include three parts: disk-cam,support point and mechanical arm.The mechanical arm could roll around support point in a certain angle range,through the profile curve of disk-cam,the movement of mechanical arm could be controlled to finish shelling process.The groove flute harm structure has been designed,the structure could through reduce the deformation of pecan under impact to protect the kernel from damage,and within few socket on the inner wall of groove,it could change the surface load into linear load and achieve a better shell break quality.According to the movement requirements of shelling system,the structure dimensions of mechanical was built,the push movement angle of cam was optimized by inverse method and the practical cam profile curve was designed.What’s more,the transmission system and the time sequence’s relationship on all the actions are both introduced.Transmission system diagram and one time sequence’s diagram on the real cracker are showed in the paper.After the physical prototype of mechanism was manufactured,the field test have been down,object of this paper was pecan taken from Ningguo city,Wannan area of Anhui province,three group of pecan was been selected out for test.and the results showed that the prototype working performance is stability and high-quality.While the rotating speed of camshaft was 52 r/min,the pecan moisture content set nearly to14.55%-16.35%,and diameter volume between 18 mm to 22 mm,the break shell rate is high,three test group is 99.59%,99.40% and 99.31% respectively,and kernel damaged rate is low,5.77%,7.00% and 6.01% for each group respectively.The processing efficiency is also higher than traditional shelling equipment,could reach95.54 kg/h,98.00 kg/h and 91.25 kg/h respectively.The test performance of prototype can basically meet the production demands.The research achievements can also enrich and perfect the mechanism and method for shell break of walnut,provide the technology and equipment support to realized the mechanization of pecan processed industry. |
