高速履带式推土机行走系统仿真与履带板分析

发布时间：2018-11-10 13:26

【摘要】：推土机是广泛用于土石方工程中的比较常见的一种工程机械机种。相对于轮胎式推土机,履带式推土机附着性能好,能适应多种路面环境,牵引力较大,所以履带式推土机的应用更加广泛。履带行走系统是履带式推土机的重要组成部分,它不仅是推土机的运动部分,同时也是整个推土机的支撑部分,既承载整机的自重运行时又承受工作装置的行驶阻力。行走系统性能的好坏直接影响着整机性能的优劣,所以本文对高速履带式推土机的行走系统进行研究分析。首先,本文介绍了履带式推土机的行驶原理,对履带行走系统进行运动学分析;并分析履带与地面的作用关系,介绍RecurDyn中的地面数学模型;对行走系统的牵引力及阻力进行理论计算,得出了推土机的最大牵引力和行驶阻力。这些理论分析与计算,为接下来高速推土机行走系统的动力学仿真及履带板结构分析打下了坚实的理论基础。其次,利用软件RecurDyn建立整机的动力学模型,并对其施加约束和定义合适的力学参数。根据高速履带式推土机实际工作环境,在RecurDyn中建立硬质、粘土、干沙三种典型地面模型。针对高速直线行驶和推土作业循环两种典型工况进行整车动力学仿真。仿真结果表明,该推土机在不同地面不同工况下负重轮受力不同,波动较大。硬质、粘土、干沙地面上驱动轮转矩逐次变大,履带下沉量也逐次增大,其承载能力依次降低,且驱动轮转矩随着工作阻力的增大而增大。在高速直线行驶工况时,观察驾驶室座椅质心在垂直方向的加速度,可知在三种地面上该垂向加速度都小于2倍重力加速度,均在人体舒适加速度范围内。另外通过两种工况,三种地面条件的仿真分析,得出在干沙路面直线高速行驶时,履带销轴受力和履带板与负重轮Z向接触力极值最大,最大值分别为83.3kN和52.6kN,这将作为履带板有限元分析的计算工况和载荷极值。最后,为了更好地了解高速履带式推土机工作时履带板的危险区域,全面掌握履带在危险工况下的应力分布情况、变形情况,对受力情况比较复杂的履带板进行有限元分析。根据之前的动力学分析确定计算工况及约束和载荷,计算结果表明,履带板销轴局部应力较大,但小于所选材料的许用应力,符合安全要求。
[Abstract]:Bulldozer is a kind of construction machinery widely used in earthwork engineering. Compared with the tire bulldozer, the crawler bulldozer has good adhesion, can adapt to many kinds of road environment, and has great traction, so the crawler bulldozer is more widely used. The crawler system is an important part of the crawler bulldozer. It is not only the moving part of the bulldozer, but also the support part of the whole bulldozer. The performance of the walking system directly affects the performance of the whole machine, so this paper studies and analyzes the walking system of the high-speed crawler bulldozer. Firstly, this paper introduces the driving principle of crawler bulldozer, analyses the kinematics of crawler walking system, analyzes the relationship between crawler and ground, and introduces the mathematical model of ground in RecurDyn. The maximum traction and driving resistance of the bulldozer are obtained by theoretical calculation of the traction and resistance of the walking system. These theoretical analyses and calculations lay a solid theoretical foundation for the subsequent dynamic simulation of the high speed bulldozer walking system and the analysis of the crawler structure. Secondly, the dynamic model of the whole machine is established by using the software RecurDyn, and the constraint is imposed and the appropriate mechanical parameters are defined. According to the actual working environment of high speed crawler bulldozer, three typical ground models of hard, clay and dry sand are established in RecurDyn. The whole vehicle dynamics simulation is carried out under two typical working conditions: high speed straight line driving and pushing operation cycle. The simulation results show that the load bearing wheel of the bulldozer fluctuates greatly under different ground conditions. The torque of driving wheel on the ground of hard clay and dry sand increases gradually and the amount of track sinking increases step by step its bearing capacity decreases in turn and the torque of driving wheel increases with the increase of working resistance. The acceleration of the center of mass of the cab seat in the vertical direction is observed under the condition of high speed straight line driving. It can be seen that the vertical acceleration is less than 2 times of the gravity acceleration on the three kinds of ground, and all of them are in the range of comfortable acceleration of the human body. In addition, through the simulation analysis of two working conditions and three kinds of ground conditions, it is concluded that the maximum values of the pedrail pin shaft force and Z contact force between the track board and the load-bearing wheel are 83.3kN and 52.6 KN, respectively, when the dry sand pavement is running at a straight and high speed. This will be regarded as the working condition and load extremum of the finite element analysis of track plate. Finally, in order to better understand the dangerous area of crawler when high-speed crawler bulldozer is working, the stress distribution and deformation of crawler under dangerous working conditions are comprehensively grasped, and the finite element analysis of crawler is carried out. According to the previous dynamic analysis, the calculation conditions, constraints and loads are determined. The calculated results show that the local stress of the pedrail pin shaft is large, but less than the allowable stress of the selected material, which conforms to the safety requirements.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU623.5

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