玉米全膜双垄沟膜下直插式施肥机的设计

发布时间：2018-09-12 16:31

【摘要】：甘肃省处于干旱半干旱地区,这里降水少且不稳定,是中国干旱发生频率较高的地区。直到2003年甘肃农业技术工作者经过十余年的大量研究,提出了一项重大旱作农业新技术,该技术是在地表起大小双垄相间形成集雨沟槽,然后用地膜覆盖大小垄和相间的垄沟,在沟内播种作物的种植栽培技术。当前,能适应全膜覆盖双垄沟播施肥技术的施肥机械主要为手提式玉米追肥枪。由于手提式玉米追肥枪作业时劳动强度大,生产效率低,不能满足全膜覆盖双垄沟播技术的发展要求。因此,研制一种与全膜覆盖双垄沟播技术相配套的施肥机具有一定的现实意义。(1)通过对全膜双垄沟播玉米施肥技术农艺要求的掌握,分析现有直插式施肥机的工作原理以及现有直插式施肥机的不足之处,对现有的设计进行改进,设计一种新的机构满足农艺要求,弥补现有直插式施肥机的不足之处。(2)现有机具是通过凸轮—曲柄连杆补偿机构控制成穴器的直插运动,凸轮—曲柄连杆式成穴器使用凸轮来实现机具前进方向上位移的补偿,并通过曲柄连杆的运动,驱动成穴器完成垂直入土和出土的动作。为了避免现有直插式施肥机中凸轮的缺陷:凸轮加工成本较高;由于凸轮轮廓有内凹段,机具工作时,推杆与凸轮内凹段产生瞬间冲击,将推杆折弯或者卡死,不能平滑过渡,导致补偿落后,不能与曲柄-连杆机构同步作业,成穴器不能完成垂直入土和出土的动作;不能适应不同株距。设计一种新机构用来替代凸轮。凸轮在机具运行中所起的关键作用是为滑块提供循环的等速度,以补偿机具的前进速度,因此,设计了一种近等速机构,用来替代凸轮机构,并分析了近等速机构替代凸轮机构的可行性。(3)将正弦机构和转动导杆机构通过大链轮与小链轮串联起来,大链轮与小链轮分别安装在机架上,齿数比为2,这样转动导杆机构中导杆的角速度在两个周期内出现的三次最小值可以将正弦机构中平移杆速度在一个周期内出现的三次峰值逐渐拉平。让转动导杆机构中导杆的角速度在两个周期内的三次最小值对应正弦机构中平移杆速度在一个周期内的三次峰值,合理确定相应的安装位置,平移杆的速度将出现两段近等速运动。对近等速机构进行了理论分析,确定了影响速度的因素有转动导杆机构中主动杆的长度,主动杆与导杆旋转中心的距离,正弦机构中曲柄的长度和主动杆的角速度。在计算机中反复试验,初步得到各因素的取值,为后续的优化奠定了基础。(4)利用Adams/View对近等速机构的设计参数进行优化,得到了最优解。在SolidWorks中建立了整机三维模型。将整机三维模型简化,利用SolidWorks Motion进行运动仿真,得到了成穴器的运动轨迹,符合设计要求。根据甘肃省不同区域对施肥间距的要求,提出了调节间距的方案,解决了施肥间距可调的问题。
[Abstract]:Gansu Province is located in arid and semi-arid region, where precipitation is less and unstable, which is a high frequency of drought in China. Until 2003, after more than a decade of research by agricultural technicians in Gansu Province, a new technique for dryland farming was put forward. The technique was to form rainwater catchment grooves between two ridges on the surface of the earth's surface, and then cover the big and small ridges and furrows with mulching film. Cultivation techniques for planting crops in ditches. At present, the main fertilizing machinery for full film mulching and double ridge sowing and fertilization is handheld corn dressing gun. Because of the high labor intensity and low production efficiency of the portable corn dressing gun, it can not meet the development requirements of the full film covering double ridge seeding technology. Therefore, it is of certain practical significance to develop a fertilizing machine which is compatible with the technology of full film mulching and double ridge sowing. (1) by mastering the agronomic requirements of full film double ridge sowing maize fertilization technology, Based on the analysis of the working principle of the existing direct-inserted fertilization machine and the shortcomings of the existing direct-inserted fertilizer applicator, the existing design is improved to design a new mechanism to meet the agronomic requirements. To make up for the deficiency of the existing straight-insert fertilizer applicator. (2) the current machine is controlled by the cam-crank linkage compensation mechanism, and the cam-crank connecting rod hole-forming device uses the cam to compensate the displacement in the forward direction of the machine. Through the movement of crank and connecting rod, drive the hole-forming device to complete the action of vertical digging and unearthing. In order to avoid the defects of the cam in the existing straight-insert fertilization machine: the cost of machining the cam is high; because of the concave section of the cam contour, the push rod and the inner concave section of the cam have a momentary impact when the machine tool works, and the push rod is bent or stuck, so that the transition cannot be smooth. As a result, the compensation is backward and can not work synchronously with the crank linkage mechanism, and the hole-forming device can not complete the action of vertical burying and unearthing, and can not adapt to different plant spacing. A new mechanism is designed to replace the cam. The key role of cam in the operation of machine and tool is to provide equal speed of circulation for the slider in order to compensate for the advancing speed of the machine. Therefore, a kind of near isokinetic mechanism is designed to replace the cam mechanism. The feasibility of replacing cam mechanism with near-isokinetic mechanism is analyzed. (3) the sinusoidal mechanism and rotating guide rod mechanism are connected in series with small sprocket and large sprocket and small sprocket are installed on the frame respectively. The ratio of teeth to teeth is 2, so that the cubic minimum of the angular velocity of the guide rod in the rotating guide rod mechanism in two periods can gradually flatten the third peak value of the translational rod velocity in a period of the sinusoidal mechanism. Let the minimum angular velocity of the guide rod in the rotating guide rod mechanism in two periods correspond to the third peak value of the speed of the translational rod in the sinusoidal mechanism in one period, and reasonably determine the corresponding installation position. The speed of the translational rod will be two segments near isokinetic motion. The theoretical analysis of the near-isokinetic mechanism is carried out. The factors influencing the velocity are the length of the active rod in the rotating guide rod mechanism, the distance between the active rod and the rotating center of the guide rod, the length of the crank in the sinusoidal mechanism and the angular velocity of the active rod. After repeated experiments in the computer, the values of various factors are preliminarily obtained, which lays a foundation for the subsequent optimization. (4) the design parameters of the near-isokinetic mechanism are optimized by using Adams/View, and the optimal solution is obtained. The three-dimensional model of the whole machine is established in SolidWorks. The three-dimensional model of the whole machine is simplified, and the motion trajectory of the hole-forming device is obtained by using SolidWorks Motion to simulate the motion, which meets the design requirements. According to the requirement of fertilizer spacing in different areas of Gansu province, the scheme of adjusting the spacing of fertilizer was put forward, and the problem of adjusting the spacing of fertilizer was solved.
【学位授予单位】：甘肃农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S224.2

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