Experimental Research And Theoretical Analysis Of Baling Mechanism Of The Roll-disk Baling Device

In China,annual yield of straw is high but its distribution is scattered.Also,the structure of straw is loose,which leads to its high cost of harvesting(collection,storage,and transportation).Baling straw is a necessary measure to reduce its harvest cost.Balers for straw harvesting,which has been researched and developed in China,are mainly small and mediumsized balers.Due to its simple structure and convenient operation,the steel-roll round baler is widely applied.The steel-roll round baler being used in rural region in China,is likely to cause clogging in harvesting intact straw(obtained from widely applied semi-feeding rice combine harvester).Therefore,in this paper,on the basis of the analysis of the baling process of its core baling device--steel-roll baling device of the round baler,a roll-disk baling device was proposed,and its baling mechanism was investigated.The main contents and conclusions are as follows:(1)Study on the basic characteristics of straw in baling process.The bending and friction characteristics of straw,the conduction law of force during the compression of straw and the density distribution of round bales(obtained by the steel-roll round baler)were studied using a universal testing machine,a self-made compression device,and a friction coefficient measuring device.It is shown that the flexural rigidity and bending strength of straw increased with the increase of moisture content and diameter of straw.During the compression of straw,the pressure was continuously consumed and decreased along the compression direction of straw.The friction coefficient between straw and the steel plate increased with the increase of moisture content in straw.The surface structure of the steel roll and the physical properties of straw had significant influences on the friction coefficient between straw and the rotating steel roll.Moreover,the density distribution law of round bales was obtained.(2)Analysis of baling process of the steel-roll baling device.The baling process of the steel-roll baling device was studied and analyzed by using high-speed photography.The results demonstrated,failure of rotating straw-core was the main reason for clogging,when the small and medium-sized steel-roll round baler was used to harvesting intact straw in China,and high frictional resistance between intact straw and the side wall of the chamber and low friction towing force between intact straw and steel roll were direct causes for the failure of rotating straw-core.(3)Design of the roll-disk baling device.Based on the object-field model in TRIZ theory,5 factors directly associated with formation of rotating straw-core(according to the direct cause for the failure of rotating straw-core)and 2 object-field models were established,and thereby two sets of solutions were obtained.On this basis,the roll-disk baling device was put forwardand designed.Then,the roll-disk baling experimental apparatus was set up with the roll-disk baling device as the main body.(4)Baling mechanism analysis of the roll-disk baling device.The timely formation of rotating straw-core in the baling process was the key to the success of baling.Therefore,its baling mechanism was mainly embodied in the formation mechanism of rotating straw-core.In this paper,the formation mechanism of rotating straw-core in the roll-disk baling device was studied by high-speed photography and experimental analysis.The results demonstrated the friction drive of the disk boosted the fluent movement of initial straw and the rapid entering to the accumulation of straw-core during formation of the rotating straw-core.During the accumulation of straw-core,the friction drive of the disk strengthened the contact between straw-core and the steel roll,and thereby strengthening the friction effect of the steel roll on straw-core.Under the combination of friction force of the disk and steel rolls,the accumulation process of straw-core was shortened,and the accumulated straw-core was turned to rotating straw-core quickly,which prevent the occurrence of clogging.(5)Experiment of the roll-disk baling device.The formation rate of bales and the power consumption of baling are important indicators to evaluate the performance of the roll-disk baling device.The factors affecting the formation rate of bales and the power consumption of baling were analyzed,determining that the main factors were the diameter of the disk,the speed of the steel roll,feeding rate and length/width ratio.Experiments were carried out with the formation rate of bales and the power consumption of baling as evaluation indicators.The influences of various factors on the evaluation indicators were obtained.Factors affecting the formation rate of bales were the diameter of the disk > feeding rate > speed of the steel roll >length/width ratio successively.Factors affecting the power consumption of baling were feeding rate > speed of the steel roll > length/width ratio > diameter of the disk successively.With the formation rate of bales ensured(formation rate of bales is 100%),the maximum length/width ratio that could be adapted by the roll-disk baling device was funded,the results showed that the maximum length/width ratio,1.2,at the same time,other parameters were as follows,the diameter of the disk,380 mm,the speed of the steel roll,269 r/min,feeding rate,1.7 kg/s,Field experiments of the baling device showed the roll-disk baling device was used to harvest intact straw,the formation rate of bales increased significantly,without clogging.