| The straw baler is a machine that picks and bundles crop strawa.The pick-up mechanism breaks and picks up the whole straw when it is baled.It is the first procedure of baling and it is very important.Therefore,it has great significance to the structure study and parameter analysis of the pick-up mechanism.After analyzing the baled conditions of the existing pick-up institutions,this paper found that there are problems such as unclean picking and falling straw during the picking process.To solve these problems,this paper has optimized and improved the pick-up mechanism through analysis,simulation and field experiment methods.Two new types of picking-crushing cutters are designed.In this paper,the width of the knife roller of the pick-up mechanism is studied to analyze the effect of the knife roller on the smashing and picking effect of the baler.Refer to the original baler’s job width and the balance performance of the tool,according to the current length of the corn straw,improved the roller width of the pick-up mechanism was 2.2m,and the design crusher bed is arrange in a double helix line,and the reliability of the arrangement has verified.By analyzing the advantages and disadvantages of various picking-crushing cutters,aiming at problems such as unclean picking in the baling process,the paper puts forward the wind-send theory of straw picking,and designed the blade type and V type pickingcrushing cutters.The size and the theoretical curve of the cutters were analyzed to verify the effect of the skew angle θ of the V-shaped picking-crushing cutter on pick-up performance.Because the pick-up mechanism is used for physically breaking and throwing rigid straws,the straws will have a great reaction force to pick up the cutters and will cause cutters wear.Therefore,the material of the cutters has a certain hardness and wear resistance performance of 65 Mn steel.The EDEM discrete element software was used to simulate and analyze the picking performance of the pick-up mechanism with Y-shaped,V-shaped,and blade-type pickingcrushing cutter.The graph of straw throwing quantity curve and the average throwing speed of straw were obtained and analyzed.The data obtained from the simulation showed that the throwing speed and number of straws picked by the V-type pickingcrushing crusher were greater than those of the blade-type and Y-type,and the blade-type was larger than the Y-type,indicating that the picking-crushing knife with the air-supply effect had better picking effect on the straw.Using Solidworks Flow Simulation software to perform fluid simulation analysis on the above three kinds of picking-crushing crushers,the simulation results of air velocity changes and air pressure changes in the rotation process of the pick-up mechanism were obtained,and the air speed change map and air pressure generated by the rotation of the knife roller were obtained by establishing a cut plane diagram.According to the pressure change chart,it was found that the air-flow rate of the pick-up mechanism for installing the V-shaped picking-crushing crusher is the fastest and the negative pressure is the highest.A comprehensive analysis of the simulation results of EDEM and Solidworks Flow Simulation: The designed V-shaped picking-crushing crusher with air delivery effect has the best picking effect on straw.Through the calculation and theoretical analysis of the V-shaped picking-crushing crusher,it is found that the size of the skew angle θ will have a great influence on the picking effect of the V-shaped picking-crushing crusher.Therefore,the picking-crushing crusher with the skew angle from 0 to 85° is performed.A number of simulations of the number of straw pick-up were performed once every 5° for a total of 18 times.Analysis of the simulated data shows that when the skew angle is 37.5°,the pick-up performance of the V-shaped picking-crushing cutter is best.A field comparison test was conducted between a Y-type picking-crushing cutter and a θ=37.5° V-shaped picking-crushing cutter,and the influencing factors of the quality of the baling,such as the length of forming the bale,the straw loss rate,the packing condition,and the baler’s oil consumption were performed.According to the measurement and analysis,the average baled distance of the V-type picking-crushing crusher is 3.7m shorter than that of the Y-type picking-crushing crusher,and the packing density of the V-type picking-crushing crusher blades is 6.8kg/m3 greater than that of the Y-type pickingcrushing crusher.The straw loss rate is 18.5% lower than that of the Y-type pickingcrushing cutter.The fuel consumption of the V-type cutter is about 7.7% lower than that of the Y-type picking-crushing cutter,and the parameters obtained are all in compliance with national standards.The test data of straw loss rate and fuel consumption are consistent with the conclusions obtained from the simulation analysis,which verifies the reliability of the discrete element simulation.Therefore,the V-type picking-crushing crusher with θ=37.5° has the feasibility and application value of the bundling operation. |
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