Design Of Multifunctional Straw Returning Machine And Experimental Research Of Deep-application Device’s Performance

Recently, problems of soil and water loss was becoming increasingly serious in northeast of China, which resulting in black soil layer of cultivated land thinning, soil fertility and ability of soil water conservation reducing, cultivated land increasingly barren, grain production decreasing, and threaten to the safety of national grain. Meanwhile, our country is rich in straw yield, however, the utilization of straw were lower, most of the straw for abandoned and burned, not only bringing the waste of the resource, but also making environmental pollute. Straw returning can increase the content of soil nutrient, improve the soil physical properties, increase soil microbial and enzyme activities, increase grain yield and so on. Straw returning also can enhance the soil water holding capacity, reduce soil erosion, can effectively resolve the environmental pollution problems caused by burning of straw. Meanwhile Straw returning has great significance for the protection of the ecological environment and realization sustainable development of agriculture.To solve the serious problem of soil erosion of Northeast China and environmental pollution caused by straw burning, the multifunctional straw machine was designed combined with the requirements of agrichltural machinery and agronomic. This machine mainly include straw pick-up device, straw feeding device, straw cutting device, stubble crushing device and straw deep application device etc, which can complete straw’s pickup, cutting, stubble cleaning and deep-application returning to fields at one time, and experimental study was carried out according to the deep-application device’s performance.The method used by this design process were kinematic analysis, dynamic analysis and computer aided design. The transmission system adopts the combination of mechanical transmission and hydraulic transmission, and the control system adopts the control mode of mechanical-electrical-hydraulic, the power source of this machine is75kW diesel engine, its working speed is4-6km/h, The equipment is suitable for both farmland operation and ridge tillage operations in peace of the Northeast of our country, its operating width is3ridge (ridge distance is600-700mm); the straw pickup device of the machine adopts three chain double grab pickup device, its width is1350mm; straw feeding device has two pair of feed rollers, each of the feeding roller diameter were150mm and180mm, the line speed of feeding roller is2.85m/s; choose the plate hob cutter chopper as the chopper of straw cutting device, shredding drum speed is 1480r/min, the length of stalk shredding is10-30mm; the stubble roller speed of the stubble crushing device is404r/min, stubble crushing depth is8-12cm; straw deep-application depth is20～35cm, straw deep-application amount can be controlled by adjusting the screw conveyor speed.Straw deep-application device is the key device of the machine, the performance of straw deep-application device affects the quality and efficiency returning to field directly. In order to further optimize and design structure of straw deep-application device, select the appropriate straw deep-application operation parameters, select the screw speed, the length of stalk shredding, straw moisture content and diameter of conveying pipe as factors, choose straw volume flow rate which is straw deep-application amount as test index. Research results show that:the increase of straw deep application amount with straw moisture content and the length of stalk shredding decreases, increases with the deep application of screw speed, diameter of conveying pipe;and the four factors on the straw deep application influence from large to small is as pipe diameter, stalk length, stalk moisture and deep application screw speed.The paper is mainly based on the design of multifunctional straw returning machine, the structure design of the main working device and determination of its parameters. Through the analysis and the design of the whole machine, and the research of the straw deep-application device’s performance test on the influence of some operation parameters, it can provide technical guidance for the rational use of the machine, but also provides a new idea for design the new type multifunctional straw returning machine, it has reference value to improve the comprehensive performance study straw returning machine.