Development And Test Of A Squeezed Walnut Shell Breaking Machine With The Self-Grading And Multi-Station

It is an important link to enhance the economic value and industrialization of walnuts in walnut shelling and kernel extraction.At present,the walnut shell breaking process mostly relies on manual labor in China,which lead to many problems such as low shelling efficiency and high labor intensity.It is an inevitable trend to realize the mechanization of walnut shelling and kernel extraction while there are few mature applied walnut shelling and kernel extraction machines.Therefore,it is necessary to carry out the research work of walnut shell breaking equipment.According to the previous design experience,an innovative equipment is designed to achieve walnut classification screening and intermittent extrusion.In view of the research problems,this paper mainly includes the following work:1)The research on the breaking mechanism and mechanical properties of walnut shell was conducted.Firstly,"Pao walnuts" of Chengkou county in Chongqing was taken as the experimental object.The physical parameters including the three-diameter size and shell thickness of walnut were measured to carry out the statistics and analysis with the characteristics of walnut shape were summarized.Secondly,based on the thin shell theory,the mechanism of walnut cracking source was studied.It was concluded that walnut cracking is more uniform under multiple pairs of concentrated force and alternating stress,which is conducive to breaking the shell.Then,the micro-control electronic universal testing machine was used to simulate the walnut shell breaking effect under a single load.To provide basic parameters for following design,the force required for walnut shell breaking with three diameters was tested.Moreover,the finite element static analysis of walnut shell stress was carried out.Finally,the difference between the results of compression test and static simulation analysis were compared.2)The integrated squeezing and self-grading with multi-station walnut shell breaking machine was designed.Aiming at solving the problems of the existing machines,a mechanism that combines shaftless screw conveying and grid-type drum screen.It can also realize the function of walnut self-grading pretreatment and shell breaking.Firstly,the overall design scheme of the shell-breaking machine is proposed.Secondly,the grid grading roller screen is designed to realize the self-grading pretreatment.Based on the research on the principle of screw conveying materials,the shaftless screw conveying mechanism is designed to realize the walnut screw conveying.Then,according to the shell breaking principle,a series of multi-station shell breaking teeth and a semi-circular arc extrusion plate are designed to achieve precise extrusion and shell breaking.Finally,the hopper and walnut guide groove are also designed and the related standard parts are selected.3)The ANSYS software was used to analyze the key parts of the shell breaking machine.Firstly,the strength of the frame was checked by static finite element analysis.Then,the modal analysis of the spindle was carried out to test the possibility of resonance between the spindle and the external excitation.Finally,the transient dynamics analysis of the shaftless screw conveying mechanism was carried out and the important dimension parameters are optimized.4)The shell-breaking prototype machine was made and the shell-breaking effect test was carried out." Pao walnuts" of Chengkou county in Chongqing was used as the testing object.Firstly,to find the optimal combination of grading parameters,the orthogonal optimization experiments on the different factors that affect the grading rate of the broken shell prototype were conducted.Secondly,a comprehensive experiment on the factors that affect the effect of broken shells was conducted to determine the optimal shell breaking parameters.Finally,the optimal parameters were verified by carrying out the shell breaking test on testing object.Then the classification rate,the shell breaking rate,the exposure kernel rate and production efficiency of the shell breaking machine were obtained.