双向驱动型链传动构型运动学特性分析与参数优化研究

发布时间：2018-06-22 11:21

本文选题：轨道约束 + 双向驱动　；参考：《天津理工大学》2014年硕士论文

【摘要】：在机械传动中，链传动是一种传递运动的重要方式。链传动相比齿轮传动和带传动具有较低要求的安装精度，传动精度准确能等一系列的优点。因此链传动广泛的被应用于各种机械的动力传动当中。但是对于低速重载以及需要稳定速度的传动系统中，此类链传动有着明显的缺点—链传动的多边形效应。由于多边形效应的存在，使得速度产生明显的规律性变化并产生明显的冲击力，影响传动速度的稳定性，也加大了链条的磨损和链传动系统断裂破坏的几率，该问题在轨道约束型链传动中同样存在。因此，本课题的目的是解决特殊轨道双向驱动型链传动的多边形效应，为以后的多边形效应研究提供一种新的思路和方法。本课题结合实际的带有空间位置条件约束的低速重载的轨道约束型链传动系统，分别采用了优化轨道半径、拟合负载仓中心轨迹、等效模型替换、解析法速度分析、二自由度五杆机构模拟、描点等方法对整个链传动系统的结构和运动情况进行了分析。本课题具体的研究内容如下： (1)首先研究了传统的链传动在运动过程中存在的多边形效应。从速度方面和受力方面分析了对运动传递产生的影响。并研究了链轮上存在的驱动力包含的几个主要参数对驱动力产生的影响。 (2)在根据已给定的有限的空间位置条件下，对链传动系统进行轨道优化设计，，采用了一种新型的具有轨道约束的双向驱动型U型链传动系统，并与传统的普通链传动进行比较，该新型链传动显著提高了在垂直空间上的利用率。之后，依次总结出该链传动系统在垂直和水平方向以及各轨道半径之间的约束关系表达式，通过MATLAB中fmincon函数对整个链传动系统的各轨道半径进行了优化选择，确定了整个链传动系统的具体结构参数，根据要求选取其中的最优尺寸结构，再根据此尺寸采用拟合和方法得出负载仓的中心轨迹曲线。 (3)将部分链条系统用铰链四杆机构进行了等效替代，并应用解析法分析了该部分中杆件的速度和加速度，再应用ADAMS软件模拟仿真，得出了各杆件的运动曲线。由于链传动系统速度不稳定，尝试将速度抵消为匀速，从速度方面分析得出补偿轨迹。应用二自由度五杆机构模拟法以及弧长相等的方法分析，结果显示该两种方法并不能得出有效的补偿轨迹。采用描点法在过渡圆弧得出了较为理想的补偿轨迹。
[Abstract]:In mechanical transmission, chain drive is an important way to transfer motion. Compared with gear transmission and belt transmission, chain transmission has a series of advantages, such as lower installation accuracy and accurate transmission accuracy. Therefore, chain drive is widely used in all kinds of mechanical power transmission. However, for low speed and heavy load transmission systems with stable speed, this kind of chain drive has obvious drawback-the polygon effect of chain transmission. Due to the existence of polygon effect, the velocity has obvious regular change and obvious impact force, which affects the stability of transmission speed, and increases the probability of chain wear and chain transmission system fracture. This problem also exists in the track constrained chain drive. Therefore, the purpose of this paper is to solve the polygon effect of the bidirectional drive chain drive with special track, and to provide a new way of thinking and method for the study of polygon effect in the future. Combining with the actual track-constrained chain drive system with space position constraints, this paper adopts the optimization of track radius, fitting the central trajectory of the load bin, equivalent model replacement, and analytical velocity analysis, respectively. The structure and motion of the whole chain drive system are analyzed by means of simulation and drawing point of two degrees of freedom five bar mechanism. The main contents of this paper are as follows: (1) the polygon effect of the traditional chain drive is studied. The influence of velocity and force on motion transfer is analyzed. The influence of several main parameters of the driving force on the sprocket is studied. (2) according to the given limited space position, the optimal design of the chain drive system is carried out. A new type of bi-directional driving U-type chain drive system with track constraints is adopted and compared with the conventional chain drive. The new chain drive improves the utilization ratio in vertical space significantly. After that, the constraint relation expressions of the chain transmission system in vertical and horizontal direction and between each track radius are summarized in turn, and the optimal selection of each track radius of the whole chain transmission system is carried out through the fmincon function in MATLAB. The specific structural parameters of the whole chain transmission system are determined, and the optimal size structure is selected according to the requirements. According to this dimension, the center trajectory curve of the load bin is obtained by fitting and method. (3) the hinge four-bar mechanism is used to replace the partial chain system, and the velocity and acceleration of the bar in this part are analyzed by using the analytical method. The kinematic curves of each member are obtained by using Adams software. Because the speed of chain transmission system is unstable, this paper attempts to cancel the velocity to a uniform speed, and obtains the compensation track from the velocity aspect. The simulation method of two-degree-of-freedom five-bar mechanism and the method of equal arc length are used to analyze the two methods. The results show that the two methods can not get an effective compensation trajectory. A more ideal compensation trajectory is obtained by using the point drawing method in the transition arc.
【学位授予单位】：天津理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TH132.45

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