【作者】 王磊；

【导师】 姚英学；

【作者基本信息】 哈尔滨工业大学 ， 机械制造及其自动化， 2010， 硕士

【摘要】 数控机床在加工的过程中,在各种热源:如轴承发热、电机发热、导轨发热及其它热源的作用下,会导致机床上的部件发生不同程度的热变形,在这些热变形的叠加作用下,导致机床刀尖处的位置精度遭到破坏,由此导致的误差称为热误差。据资料显示,数控机床在加工过程中由于热变形引起的加工误差占机床全部误差的40～70﹪。重型数控机床用于加工特大型零件,在航天、航空等工业领域有着广泛的应用,其具有体积大、质量重、行程范围远等特点,由于各部件热变形导致的热误差不容忽视。本论文针对某型号重型数控落地铣镗床,对其热误差进行了分析并预测。论文主要进行如下研究工作:阐述了传热学相关理论及有限元方法在其中的应用,并建立了机床的三维有限元模型。在对机床的热源和边界条件进行分析并计算后,对机床温度场和变形场进行了分析。研究了温度传感器的优化选择方法。在机床上根据经验初步布置了温度传感器之后,进行热误差实验,采集温度和热误差数据。利用传感器的优化选择策略:主因素策略、互不相关策略、最大灵敏度策略,筛选出用于热误差建模的温度关键点。为了考虑不同策略对选取结果的影响,在最后一步中根据策略的不同出了两种方案。研究了多元线性回归理论及其在热误差建模中的应用。针对上述两种方案,基于逐步回归法选取了回归变量并分别在X、Y、Z三个方向建立了热误差预测模型。分析并比较两种建模结果的预测精度后,得出最终的热误差建模方案。更多还原

【Abstract】 During the process of machining, there are varieties of heat sources, such as the beating of bearing, the beating of motor and the beating of slide-way, they can lead to the thermal distortion the different structural elements. Under the action of superposition of various thermal distortions, the accuracy of the position of the tool is destroyed, as it is called thermal error. It has been shown that the thermal error of machine tool can account for 40～70 percents of the total machine error.The heavy NC machine tools which are widely applied in the field of aerospace and others are usually used on machining of heavy parts, which has the characteristic of large volume, heavy mass and long range of travel, and its thermal errors that are caused by thermal deformation cannot be ignored. Aiming at some heavy type milling boring ma-chine tool, the machine tool thermal errors are analyzed and forecasted in this disserta-tion. The main research achievement of this dissertation is as follows:The theory of heat transfer and the application of finite element is elaborated, and also the finite element model is modeled. After analyzing and calculating the heat and boundary conditions, this dissertation analyzed the temperature field and thermal defor-mation .The method of optimization selection of temperature sensor is researched. After ar-ranging the temperature sensors by experience on the machine tool, the thermal error ex-periment is conducted. By the use of strategy of optimization selection of temperature sensor, such as principal factor, mutually uncorrelated and maximum sensitivity, the crit-ical temperature points that are used for thermal error modeling are selected in three pro-cedures. Considering the impact on the selecting result, two different proposals are raised according to the strategy in the last procedure.The application of theory of the multiple linear regression on the thermal error mod-eling is analyzed. Aiming at the two proposals that are discussed, the regression variables are selected by stepwise weakening and the thermal error models are established in three directions. After analyzing and comparing the forecast precision of the results of the two models, the final thermal error model is recommended.更多还原