高速电主轴的性能评价及实验研究（本科毕业论文设计）.doc

高速电主轴的性能评价及实验研究（本科毕业论文设计）
摘 要

高速加工能显著地提高生产率、降低生产成本和提高产品加工质量，是制造业发展的重要趋势，也是一项非常有前景的先进制造技术。实现高速加工的首要条件是高质量的高速机床,而高速机床的核心部件是高速电主轴单元，它实现了机床的“零传动”，简化了结构，提高了机床的动态响应速度，是一种新型的机械结构形式，其性能好坏在很大程度上决定了整台机床的加工精度和生产效率。本文对高速电主轴的动态性能进行了研究，主要做了以下几个方面的工作：
介绍了电主轴的结构组成及工作原理，基于传递矩阵法对高速电主轴进行动力学分析，并利用传递矩阵法将其简化并进行分段建模，对轴系中典型单元的状态进行了数学描述；针对电主轴结构的特殊性，修改了简化模型中部分典型单元的状态向量，得到电主轴的传递矩阵方程即轴系的频率方程；以60000 r/min电主轴为例，描述了用修改后的传递矩阵方程对其进行求解的计算过程，得到了该电主轴的固有频率及振型；并对其进行了自由模态实验，提取该电主轴的模态参数（固有频率、阻尼和振型）；实验结果与传递矩阵法的计算结果基本吻合。
针对高速电主轴高转速难加载的问题，提出了将电主轴作为测功机的核心电机对测功机进行改造，并用其对被测电主轴进行加载实验的方案。根据转速的不同，分别给出了两种不同的动态加载测试方案。详细描述了对拖式加载方法的系统构成和加载原理，该系统不但可以完成对电主轴的加载，还可以测出加载过程中电主轴的基本参数并绘制相应的特性曲线，使电主轴在不同工作点的状态一目了然。并应用该系统对15 000 r/min的电主轴进行加载实验，测出电主轴的各输入电参数，并描绘特性曲线，解决了高速电主轴无法进行准确加载实验的问题。


关键词：高速电主轴，传递矩阵，动力学，实验



ABSTRACT

High speed machining (HSM) has become the mainstream of manufacturing for drastically increasing productivity, reducing production costs and improving the product quality. HSM is also a promising advanced manufacturing technology. In the realization of HSM, machine tool generally plays an all-important role and high speed motorized spindle is the key technology for a machine tool. The machine tool equipped with high speed motorized spindle has characteristic of the zero-transmission and simplified of the machine structure. With use of new mechanical structure, the high speed motorized spindle has much better dynamic performance in response to the high demands in this machine. In general, overall performance of high speed machine in terms of the machining precision and productivity is largely dependent upon the performance of the equipped high speed motorized spindle.The dynamic analysis and experiment on high speed motorized spindle are researched. The major contribution of the work is summarized as followings.
The structure and principle of the high speed motorized spindle is introduced. The dynamic analysis is carried out on high speed motorized spindle with use of the transfer matrix method, which includes the structure simplification and modeling segmentation. Typical elements’ states of the shafting are describled by mathematical method. For the special structure of the high speed motoried spindle, some state vectors of typical elements in the simplified model are modified. Then transfer matrix model of the high speed motorized spindle ,which is also the frequency model of the shafting ,is derived. As a case study , the natural frequency and critical speed of high speed motorized spindle with 60000 rpm are calculated by the modified model.. Meantime a free mode experiment is carried out under the 6000 rpm high speed motorized spindle in order to acquire the modal parameters,such as natural frequency, damp and mode shape. The experimental results exhibited that modal parameters from the test are matched with the theory calculation .
Loading and measuring the load applied on a high speed motorized spindle in the non-machining state is an important issue in performance eva luation of high speed motorized spindle. A new method is developed through modifying a dynamometer to make the loading possible in the experiment. According to the different rotating speed, two types of dynamic loading test ways which are the inter-drag method and the non-contact method are proposed. The structure and principle of the inter-drag loading method are described in detail. The system can not only load to the high speed motorized spindle, but also measure basic parameters of the high speed motorized spindle and present the corresponding curves which make it visible for states of the high speed motorized spindle at different working points. The inter-drag loading system is applied in experiment on the high speed motorized spindle in which the highest rotating speed is 15 000 rpm. The characteristic curve of this high speed motorized spindle is depicted. Analyzing and dealing with the test data, the inherent characteristic and existent problem of the motorized spindle are gained. Proposed method makes it possible to accurately loading on a high speed motorized spindle


Keywords: High speed motorized spindle, Transfer Matrix, Dynamics, Experiment

目录

摘 要 I
ABSTRACT II
1绪论 1
1.1引言 1
1.2本课题研究的背景意义 1
1.2..