Research On Thermal Expansion Of Precision Mechanical Parts And Material Precise Coefficient Of Thermal Expansion

With mechanical precision improving from micron scale to nanometer scale in modern times, scientists in world more and more pay attention to the influence of thermal deformation in precise process and precision instruments. Under thesustentation of NSFC(National Nature Science Foundation of China) project "theoretical and applied research of mechanical assort thermal deformation errors" (item number: 50075023) and Taiwan Science and Technology Committee project, This paper summarizes domestic and abroad thermal deformation achievements; .systematically studied mechanical parts' thermal deformation influenced by mechanical parts body factor; establishes thermal deformation mathematics model with mechanical parts body factors, and the model is demonstrated by experiments. On the basis of these achievements, the material precise coefficients of thermal expansion are deduced and a large number of experiments are made to prove these results. On the base of these theoretical and experimental achievements, the standard material precise coefficient of thermal expansion in precision engineering can advance further.The main contents and innovations of the dissertation include: On the basis of synthetically analysis about domestic and abroad achievements, by transforming thermal deformation and mechanics model, the rule of typical parts body's thermal deformation is researched, theoretical analysis on rules of square body, cylinder and sphere thermal deformation are given, and parts thermal deformation mathematics model is deduced for the first time.In the analysis of typical parts body thermal deformation mathematics model, the typical finite difference method is developed into an analysis method which can be used to acquired the general rule of the body thermal deformation, and this analysis method provides a kind of effectual arithmetic in researching parts thermal deformation with complex shape parts.This paper comprehensively studies material precise coefficient of thermal expansion, analyzes the defect of the traditional material coefficient of thermal expansion, demonstrates the quantitative evaluation and applicable scale of the precision under traditional material coefficient of thermal expansion, gives the solution to obtain material precise coefficient of thermal expansion. Meanwhile,this paper analyzes several current definitions of material coefficient of thermal expansion, demonstrates the precision range with different coefficient definitions, gives the principle and method in the application and industry, and this theory possesses important practical value. We theoretically analyzes material coefficient of thermal expansion defined by the cylinder and sphere standard samples, the material coefficient by measuring sphere standard is more scientific. This paper establishes mathematics model of coefficient of thermal expansion with typical shape parts to provide theoretically basis for establishing more scientific precise coefficient of thermal expansion.This paper studies the changing rule of material coefficient of thermal expansion with different sample parts, including 25 kinds of general material in precision engineering and 16 kinds of material (one kind of material includes 4 different dimension samples, altogether 64 pieces) provided by Taiwan National Chengkung University, their coefficient was tested through experiments, as the information of the material precise coefficient of thermal deformation, these data were analyzed and the important theoretical achievements have acquired, those results will help establish the uniform standard material precise coefficient of thermal deformation.This paper develops high-precision three dimension thermal deformation experiment instrument ?even temperature field high-precision experiment instrument, it has constant temperature cabinet controlled by microcomputer, located by inductance measuring probes, three dimension jiggle desk and double-frequency laser interferometer measuring system, these function developed to enhance its applicability. The high-precision three...