针对目前国内山核桃破壳机实用机型少,破壳率较低,果仁损伤率较高等情况,提出了一种仿生敲击(即模仿人工加工山核桃的方式)破壳方式,研制一款仿生敲击式山核桃破壳机。根据山核桃的物料特性以及破壳时所需的各项力学特性参数,建立了破壳机构设计的数学模型。确定了敲击臂的结构尺寸,优化了凸轮结构,并最终得到了凸轮的实际轮廓曲线。该文阐述了破壳机的总体结构与性能,建立了整机的三维实体模型,并根据建模制造了样机。该样机通过现场试验,结果表明:山核桃的含水率为14.55%-16.35%,大小为直径18-22 mm(沿缝合线方向)时,破壳率为99.41%,果仁损伤率为6.25%,生产率为94.93 kg/h,满足生产要求。该研究丰富与完善了坚果类果实的破壳机理与方法,为含隔坚果类的破壳机具设计与开发提供系统的理论依据和应用基础。
At present, extruding crack and centrifugal shell-breaking methods are adopted as the main strategies for pecanshell-breaking equipment. But the low production rate is hard to be improved. Meanwhile, the bad processing quality willaffect the further processing, which restricts the development of the pecan processing industry. To solve such problems, thisstudy proposed a bionic knock method, which imitated the artificial processing to shell pecan, and developed a bionic knocktype shell breaker. Design and experiments were both mainly focused on the structure and parameters of the shell breaker. Thepaper described the overall structure of prototype and introduced the technical parameters of shell breaker, and thethree-dimensional model was built by Pro/Engineer software. In this study, cell feed wheel was designed to translate pecan intofeed pipe from hopper one by one like water flow, and thus the method could avoid pecans plugging the feed pipe. The bottomof the pipe was linked with shelling system, which was one of the most important parts during the study. In order to figure outa more efficient shelling method, a bionic knock structure was designed based on the particle properties and mechanicalbehavior of pecan rupturing under knock loading, and the mathematical model of designing the shelling system was built. Thesystem included 3 parts: disk-cam, support point and mechanical arm. The mechanical arm could roll around the support pointin a certain angle range, and through the profile curve of disk-cam, the movement of mechanical arm could be controlled tofinish shelling process. The groove structure was designed, which could reduce the deformation of pecan under the knock toprotect the kernel from damage, and within a few sockets on the inner wall of groove, it could change the surface load intolinear load and achieve a better shell-breaking quality. According to the movement requirements of shelling system, thestructure dimension of mechanical parts was built, the push movement angle of the cam was optimize