Design And Experimental Research Of Cotton Stalk Pulling-out Mechanism

The foreign cotton stalk harvesting equipment mainly for the standard plant which has the same line distance, and they are basically with the rows harvested. So it cannot solve the problem that our country cotton planting spacing is not uniform, and also it cannot adapt to the complex agronomic requirements in China. Domestic cotton stalk harvester although many kinds of, but shovel type, promotion type are used to the rows harvested, so it lead to the poor adaptability of domestic diversification plant way. And the shear type, knife roller type, V tooth plate promotion type without the row harvested, but they all have fatal defects, such as shear type cotton stalk harvester's blade is easy to wear or even damage, the knife roller type cotton stalk harvester will require to go deep into soil, cutting cotton stalk and soil in the same time, caused by energy consumption is very large. Obviously it is difficult to achieve the cotton stalk harvest with low cost, not suitable for the cotton stalk harvest at present. And V tooth plate promotion type cotton stalk harvesting equipment with unstable performance. Therefore, develop a cotton stalk pulling machine without row harvested to improve work efficiency and decrease cotton stalk harvesting cost, reduce the farmers of the labor intensity, improve cotton stalk harvesting mechanization level, to adapt to the complex cotton cultivation mode, with important significance.In this paper, we designed a promoted type cotton stalk harvesting equipment, and do some related research on following items:cotton stalk physical characteristics?stalk pulling device structure?key parts of the optimization?the main body of the kinematics and dynamics analysis?the effect of stalk pulling performance of single factor and multi-factor test. The main research contents and related conclusions are as following:1)Research on physical mechanical properties of cotton stalk. In order to get the best cotton stalk pulling position, I have do some test including:the cotton stalk diameter, moisture content, shear strength, bending strength test, the results are as following:cotton stalk diameter between 9.1?15.3mm, the average diameter of 12.98mm; with time goes by the moisture content of cotton stalk is decreasing; The bending strength of the specimens go against with the water content; The bending strength between 90?210mm. In the period of cotton stalk bending strength test, we get the maximum bending strength is 37.3MPa, and the minimum bending strength is 24.3 MPa. With the decrease of water content, shear strength is roughly the trend of decreased first and then increased. Water content higher, the toughness of cotton stalk is stronger. So it is not easy to be cut off. On the contrary, the moisture content lower, cotton stalk is fragile and it is easy to be cut off. The maximum shear strength of cotton stalk is 1.21MPa, the minimum shear strength is 0.79MPa. The parts which close to ground has the highest strength and toughness of the whole cotton stalk, when pull rod, holding this position, cotton stalk may can be uprooted without broken, so the holding position of the cotton stalk pulling device was set at the position on the cotton stalk where away from the ground 150 mm.2)The structure design of drawing type cotton stalk pulling device. In order to let the cotton stalk pulling device can adapt to the characteristics of domestic cotton planting mode diversification, and the blade does not need go deep into soil to reduce power consumption and cotton root residue, according to the cotton stalk physical mechanical properties and the southern hilly mountain small plots operations, we proposed a drawing type stalk pulling scheme with large operation region. And the virtual prototype model is established using the software of SolidWorks2013. The drawing type cotton stalk pulling device is consist of cotton stalk pulling device?a cotton stalk exhausting roller device?transmission system and body frame etc. Pulling device is consist of a pulling shaft?remove components by pulling shaft, shaft sleeve, blade and other parts. Cotton stalk exhausting roller device consist of a central shaft, a supporting rod, cotton stalk exhausting teeth and other components. According to pulling force and pulling angle, pulling shafts are lean assigned from down to up in the stalk pulling device ahead direction. With the pulling shaft drive the rotation of the blade, the blade pulling the cotton stalk up first, then bring the cotton stalk to stalk exhausting roller device work area by rotating. Finally, exhaust cotton stalk by stalk exhausting roller device.3)The finite element analysis and optimization of the key parts. Use the simulation function of SolidWorks2013 to do mechanical analysis for the main working. Through the analysis to determine the stress centralized location, maximum stress values, the maximum strain and maximum displacement volume for each component, and under the precondition of satisfying the minimum safety factor to select the right material. Optimize the structure and size of the key working parts, in order to reduce design and manufacturing costs and provide a theoretical basis.4)Dynamic and kinematic analysis of the main mechanism.The drawing parts and the stalk rollers used to pull and discharge cotton stalk, the movement state of these two parts directly affects the job of drawing type cotton stalk pulling device. So this paper focus on drawing part and the stalk rollers kinematics and dynamic characteristics of these two parts. According to analysis we get the mechanical model of when the cotton stalk puling equipment pulling cotton stalk. And we also get the relationship among the displacement of the holding point on blade, speed, accelerate speed and the movement parameters of cotton stalk pulling device. And the relationship among the movement parameter of cotton stalk pulling device, speed, accelerate speed and the movement parameters of cotton stalk pulling device. So these good for us to get the best movement parameters of cotton stalk pulling device.5)Prototype test. The main index of device drawing type cotton stalk pulling device is pulling net rate and pull off rate, and the main factors of net pulling rate and pull off rate including pull shaft rotating speed, the machine speed and the angle between the earth and blade. In order to find out the effect extend of single factor or the factors to the pulling net rate and pull off, I have do the single factor and multi-factor orthogonal experiments. Through comprehensive analysis and comparison the optimal parameters of this test:shaft rotational speed 25 r/min, the angle between the earth and blade is 30 degree, the machine speed is 0.7 m/s.