牵引式甘蓝收获机关键机构设计与试验研究

发布时间：2018-11-19 11:02

【摘要】：甘蓝是我国农民种植的主要蔬菜品种之一,由于产能高、质量好、耐寒性好、储存运输方便,种植农户比较多。目前我国的甘蓝收获机械的研究尚处于起步阶段,存在收获稳定性差,收获质量不佳等问题。本文针对国内甘蓝种植占用人力较多、操作难度大、难以大批量生产、种植损失严重等一系列问题,结合农户的实际,在实验的基础上,设计一种牵引式甘蓝收获机,重点对双螺旋拔取输送机构进行了设计和优化,通过试验验证机构的可行性。(1)甘蓝的物理特性研究。在实验室测量收获期早熟结球甘蓝的高度、直径、质量等参数,测定在不同土壤情况下的甘蓝拔取力和根茎含水率。试验结果表明:甘蓝在田间的平均拔取力为192.1N;甘蓝根茎从上至下的4个不同部位(上部、中部、下部、底部)的含水率呈逐渐减小趋势,分别为89.42%、86.9%、83.775%、78.34%。(2)甘蓝收获机总体结构设计。通过调查我国东北黑龙江地区的甘蓝种植模式,确定了甘蓝收获机的设计方案。确定了牵引方式、配套动力、收获行数以及关键机构的主要技术参数。该机主要由双螺旋拔取输送机构、压顶机构、切根机构、去叶机构、水平输送机构以及传动系统等组成。对主要工作部件进行了分析与设计并进行数据优化,即压顶机构选择柔性带压顶,提升输送装置选择链条式输送方式,切割机构选择圆盘切割器,去叶机构采用液压皮带滚筒设计。(3)双螺旋拔取机构的设计与优化试验研究。对双螺旋拔取机构进行力学分析,建立了其受力分析模型,得出甘蓝在正常输送条件下的影响因子。采用四因素两水平二次正交旋转组合设计的试验方法,选择螺杆转速、杆间距离、螺杆节距、螺杆与地面夹角这四个因素,以拔取输送率和切根不合格率为目标函数,应用Design-Expert8.0.1软件进行试验数据的处理与分析,采用多目标优化的方法,进行模型优化,得到满足响应变量范围的因子的最佳组合。优化后的结构参数组合为螺杆转速为700 r/min、杆间距离为76 mm、螺杆节距为68 mm、螺杆与地面角度为16°。拔取输送率可以达到93.7%,切根不合格率低于3%,满足甘蓝收获的要求。
[Abstract]:Kale is one of the main vegetable varieties planted by farmers in our country. Because of its high production capacity, good quality, good cold tolerance, convenient storage and transportation, there are more farmers planting. At present, the research of kale harvesting machinery in our country is still in the initial stage, there are some problems such as poor harvest stability and poor harvest quality. Aiming at a series of problems, such as consuming more manpower, difficult to operate, difficult to produce in large quantities, and serious planting losses in domestic cabbage planting, a traction harvester is designed based on the experiment, which is based on the practice of farmers. The design and optimization of double helix extraction conveying mechanism were emphasized, and the feasibility of the mechanism was verified by experiments. (1) the physical characteristics of cabbage were studied. The height, diameter and quality of early maturing cabbage were measured in laboratory, and the extraction ability and rhizome moisture content of cabbage under different soil conditions were measured. The results showed that the average extraction capacity of cabbage in the field was 192.1 N. The moisture content of four different parts (upper, middle, lower and bottom) of cabbage rhizome decreased gradually from top to bottom, which was 89.42% 86.9% and 83.775%, respectively. 78.34. (2) overall structure design of cabbage harvester. The design scheme of cabbage harvester was determined by investigating the planting pattern of cabbage in Heilongjiang area of Northeast China. The traction mode, supporting power, the number of rows and the main technical parameters of the key mechanism are determined. The machine is mainly composed of double screw extraction conveying mechanism, pressing mechanism, cutting mechanism, blade removing mechanism, horizontal conveying mechanism and transmission system. The main working parts are analyzed and designed and the data are optimized, that is, the top pressing mechanism selects the flexible belt press, the lifting conveyer selects the chain conveying mode, and the cutting mechanism selects the disc cutter. The blade removal mechanism is designed with hydraulic belt drum. (3) the design and optimization test of double screw extraction mechanism. The mechanical analysis of double helix extraction mechanism was carried out, and the force analysis model was established, and the influencing factors of cabbage under normal transportation conditions were obtained. The four factors of rotating speed, distance between rod, pitch of screw and angle between screw and ground are selected by using the test method of four factors and two level quadratic orthogonal rotation combination design. The objective function is to select the conveying rate and the unqualified rate of cutting root as the objective function. The Design-Expert8.0.1 software is used to process and analyze the experimental data, and the multi-objective optimization method is used to optimize the model, and the optimal combination of factors satisfying the range of response variables is obtained. The optimized structural parameters are as follows: the screw speed is 700rmin, the distance between the rods is 76 mm, the pitch is 68 mm, the angle between the screw and the ground is 16 掳. The rate of extraction and transportation can reach 93.7, and the rate of root cutting is less than 3, which meets the requirements of kale harvest.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S225.92

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