割刀行星齿轮传动机构的优化设计研究

发布时间：2018-05-08 14:10

本文选题：割刀传动 + 行星齿轮机构　；参考：《西北农林科技大学》2011年硕士论文

【摘要】：割刀传动机构是联合收割机的重要部件,其工作性能直接影响着联合收割机作业的质量和效率。目前国内的联合收割机上大多采用的是曲柄连杆机构、摆环机构。其共同缺点是:刀杆受到垂直或水平方向的分力,导致刀杆易造成断裂。而行星齿轮式传动机构的结构特点是刀杆头不受垂直方向的分力和前后水平分力作用,因而磨损小,振动也小,结构紧凑,工作可靠。至今,世界上只有Deutz-Fahr联合收割机上的割刀采用了行星齿轮传动机构,对其研究、设计极少。因此,设计、研究行星齿轮割刀传动就十分必要。针对割刀的摆环传动机构使刀杆受到垂直分力的作用,导致刀杆受到振动和易断裂的缺点,本文利用优化设计的手段,设计了联合收割机行星齿轮传动机构,并对所设计的机构的合理性与工作可靠性进行了分析与验证。应用Matlab软件的优化工具箱,对联合收割机行星齿轮传动机构进行优化设计;以所得的优化参数用三维机械设计软件Pro/E完成了虚拟装配和运动学仿真;再把模型导入到有限元分析软件ANSYS中,按照行星齿轮传动机构的特点和实际工作条件,对行星齿轮进行了弯曲静力分析,求证设计的合理性。全文的研究内容和结果如下: (1)以东方红4LZ-2.5联合收割机的割刀传动机构为例,分析了现有的摆环箱传动机构的运动规律,同时分析行星齿轮传动机构的运动特性,得到了行星齿轮传动机构要满足割刀的往复直线运动,各零部件尺寸要满足的条件。 (2)以体积最小为目标函数,以满足能实现割刀运动的尺寸条件、满足行星齿轮设计过程中的尺寸条件、满足额定承载能力条件等为约束条件,建立行星齿轮传动机构优化设计的数学模型。 (3)采用基于Matlab的遗传算法工具箱对目标函数进行优化,得到行星齿轮传动机构的几何参数的最佳组合,根据实际情况圆整优化结果。 (4)在Pro/E软件中,完成行星齿轮传动机构3D造型和虚拟装配,检验零件尺寸的正确性。运用Pro/E软件的运动仿真功能,对设计的行星齿轮机构执行接近实际状况的运动仿真测试,得到割刀的运动曲线,和东方红4LZ-2.5联合收割机现有传动系统下的割刀运动做比较,验证设计的合理性。 (5)根据行星齿轮传动机构处于低速重载工况条件,针对优化设计后的齿轮进行弯曲强度有限元分析,验证优化设计结果的正确性。研究结果表明:本文所优化设计的行星齿轮机构,经Pro/E软件运动仿真的检验知,与东方红4LZ-2.5联合收割机现有传动机构的运动相近,得出其设计尺寸可行;经有限元弯曲应力的分析,知所设计的齿轮满足强度要求。继一系列的CAD,CAE技术的设计、检验之后,知本文所设计联合收割机的行星齿轮传动机构提高了工作性能和可靠性。从而从根本上改善了收割机割刀的受力状况,解决了刀杆断裂问题,提高了联合收割机的工作效率。
[Abstract]:Cutter drive mechanism is an important part of combine harvester, and its working performance directly affects the quality and efficiency of combine harvester operation. At present, crank linkage mechanism and pendulum ring mechanism are mostly used in combine harvester in our country. The common disadvantage is that the pole is easily broken by vertical or horizontal force. The structure of the planetary gear-type transmission mechanism is characterized by the fact that the blade head is not subjected to vertical and horizontal forces, so the wear is small, the vibration is small, the structure is compact, and the work is reliable. Up to now, only the cutter of Deutz-Fahr combine machine adopts planetary gear transmission mechanism. Therefore, it is necessary to design and study the planetary gear cutter transmission. Aiming at the shortcoming that the shimmy ring drive mechanism of cutting tool causes the cutter rod to be subjected to vertical force, which leads to the vibration and breakage of the cutter rod, this paper designs the planetary gear transmission mechanism of combine harvester by means of optimization design. The rationality and reliability of the designed mechanism are analyzed and verified. The optimal design of planetary gear transmission mechanism of combine harvester is carried out by using the optimization toolbox of Matlab software, and the virtual assembly and kinematics simulation are completed by using 3D mechanical design software Pro/E. Then the model is introduced into the finite element analysis software ANSYS. According to the characteristics of the planetary gear transmission mechanism and the actual working conditions, the bending static analysis of the planetary gear is carried out, and the rationality of the design is verified. The research contents and results are as follows: Taking the cutter drive mechanism of Dongfanghong 4LZ-2.5 combine harvester as an example, this paper analyzes the motion law of the existing swing ring box transmission mechanism, and analyzes the motion characteristics of the planetary gear transmission mechanism at the same time. The conditions that the planetary gear transmission mechanism should meet the reciprocating straight motion of the cutter and the dimensions of each component should be satisfied are obtained. (2) taking the minimum volume as the objective function, to satisfy the size condition which can realize the movement of the cutter, to satisfy the dimension condition in the design process of the planetary gear, and to satisfy the condition of the rated bearing capacity, etc. A mathematical model for optimal design of planetary gear transmission mechanism is established. 3) the objective function is optimized by genetic algorithm toolbox based on Matlab, and the optimal combination of geometric parameters of planetary gear transmission mechanism is obtained. In Pro/E software, the 3D modeling and virtual assembly of planetary gear transmission mechanism are completed, and the correctness of the dimensions of the parts is verified. Using the motion simulation function of Pro/E software, the kinematic simulation test of the designed planetary gear mechanism is carried out, and the motion curve of the cutter is obtained, which is compared with the movement of the cutting tool under the existing drive system of the Dongfanghong 4LZ-2.5 combine harvester. Verify the rationality of the design. 5) according to the condition that the planetary gear transmission mechanism is in low speed and heavy load condition, the bending strength of the gear after optimized design is analyzed by finite element method, and the correctness of the optimized design result is verified. The results show that the planetary gear mechanism optimized in this paper is close to the motion of the existing drive mechanism of Dongfanghong 4LZ-2.5 combine harvester by Pro/E software motion simulation, and the design size is feasible. Through the finite element analysis of bending stress, it is known that the designed gear meets the strength requirement. After a series of design and inspection of CAE technology, it is known that the planetary gear transmission mechanism of the combine harvester designed in this paper has improved the working performance and reliability. Thus, the mechanical condition of the cutter is improved fundamentally, the problem of cutter pole fracture is solved, and the working efficiency of combine harvester is improved.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH132.41

【引证文献】