Kinematics analysis and experiment of crank rocker vibrating coarse sorting machine for unshelled oil-tea fruit

Abstract: Nowadays because the separation step of shell and seed of oil-tea fruit wants to reach the ideal effect by one pace, they can not get satisfactory separation rate of shell and seed. In our study, we determine to choose roughing at first, and then select cleaning method. In order to improve the efficiency of the late selection and separation, design an oil-tea fruit coarse sorting machine which is simple in structure and convenient in manipulation and easy to latter careful sorting. Its work is to shell big shells, break tea fruit, without breaking separate tea fruit and dross among the mixture of shells and seeds of oil-tea fruits which are broken. And leave small broken shells and intact tea seed into the next selection. Now, this paper wants to proof the rationality of the design of oil-tea fruit roughing machine. First, we simplify it as crank and rocker mechanism, and analyze it with the principle of the screening. When the speed of screen increases, materials collide with the edge of the mesh, and pile up on the screen and are difficult to go through the screen; and on the other hand when the speed of screen decreases, the interaction between material particles and sieve is small, which leads to lower screening efficiency. Then, we analyze the motion parameters of coarse sorting machine through the force analysis, and there are 3 kinds of forces on the material and a kind of inertia force. We use static balance and dynamic static to analyze the material which has a tendency to slide along the screen surface. Through the analysis, we conclude that the motion parameters meet the design requirements. Second, we carry out the coarse sorting machine's dynamic simulation and analysis through ADAMS software toward the 5 equidistant material models placed on the model screen surface position. Combining the work principle of shaker with ADAMS software, carry out the kinematics simulation analysis, and get the curves of the amplitude of 5 material models. By using the law of diminishing amplitude we analyze the change of screen surface amplitude and validate that the amplitude design of coarse sorting machine is reasonable. Third, through orthogonal combination experiment of 3 levels and 3 factors, it is concluded that for the influence on the retention rate of seed, the incline angle of screen surface ranks first, the screen length ranks second and the crank speed comes last. And as for the influence on screening efficiency, the order from high to low is the screen length, the incline angle of screen surface, and the crank speed. Besides, by analyzing the response surface, it is concluded that the influence of crank speed and screen length on the retention rate of seed interacts with that on screening efficiency. Then use Design-Expert software to obtain the optimum working conditions of oil-tea fruit roughing machine. When the crank speed is 276.12 r/min, the incline angle of screen surface is 6.69°, and the screen length is 1005.8 mm, we can get the optimum retention rate of seed, which is 96.84%, and also the optimum screening efficiency, which is 96.77%. Oil-tea fruit roughing machine meets the design requirement. The research results provide a reference for the design of later accurate selection machine.