随着工业的不断发展，对生产精度的要求日益提高，人们越来越重视加工误差的减小和避免。在对减小加工误差的方法研究过程中发现，机床加工零件的误差中，由于机床热变形引起的加工误差占很大比重，尤其是在高精密加工过程中，尤为显著，所以减小机床的热变形成为提高加工精度的重要途径。 主轴箱是机床中的重要部件，它在热源作用下，温度场的分布及热变形的情况直接影响到加工精度，本文以QLMT6300龙门车铣复合机床的主轴箱为研究对象，通过对其热源发热规律的研究，借助有限元分析软件，得到主轴箱稳态、瞬态温度场分布及主轴热变形大小，为机床结构的优化及热误差的补偿提供理论依据。主要工作如下： 1．对机床主轴组件进行三维建模，为了避免在过小的细节处出现大量的节点和单元，简化模型中的细节，忽略次要零件，建立有限元分析模型。通过计算得到QLMT6300主轴箱中主要的热源：轴承及齿轮工作时的摩擦热作为主轴有限元热分析的外加载荷；根据机床工作时的具体情况，计算主轴方滑枕壁面及主轴端面与空气的对流换热系数，将其作为热分析时的边界条件（对流边界条件）。 2.通过有限元分析得到主轴组件、方滑枕、减速箱的温度场分布云图及瞬态温度场变化曲线。 3. 对温度场分析结果与机床结构做热—结构耦合分析，得到机床主轴箱的热变形云图。分析结果表明主轴安装刀具的部位并不是热变形最大的地方，主轴上的最大热变形产生在主轴与中间轴相连部位。 4. 将仿真分析的结果与试验测试结果进行对比，一方面用于修正仿真分析模型，为进一步分析该机床在不同转速下主轴的热变形提供理论依据，另一方面，验证了基于有限元分析得到主轴箱温度场及热变形这一方法的正确性，为热误差补偿提供理论依据。

As the development of industry, the accuracy requirements of production are increasing. People pay more attention to the reduction and avoidance of processing errors. During the research process of the method for reducing processing errors, people find that the errors caused by the machine thermal deformation takes account for a large proportion, particularly, in the precision machining process. So reducing the thermal deformation of machine tools becomes an important way to improve the machining accuracy. Spindlebox is an important part of machine tools. Under the action of multiple heat sources, the temperature distribution and the thermal deformation of the spindle directly affect the processing precision. In this paper, taken the QLMT6300 turning & milling large gantry machine tool as the researched subject, the law of heat for the spindlebox is researched by the assistant of Finite Element Method(FEM), and the spindle temperature distribution and the thermal deformation are found. The result can be a theoretical basis of the optimization and thermal compensation for the machine tool structure. The main work of this paper is as follows: 1. Modeling the components of the spindle, by simplifying the 3D model, the FEM model was created. By calculating, the heat sources of the spindle box was got, which were the friction heat caused by bearings and gears. Considering the machine tools working condition, the heat convection coefficient between the spindle component and the air was calculated abd taken as the boundry conditions. 2. By the thermal analysis for the spindle components, ram and speed-reduction box, the temperature cloud charts and the transient temrature curves were got for further studies. 3. With the results of the above analysis, the thermal deformation of the structure can be analyzed, which means the largest deformation of the spindle was on the connect with the middle spindle, not the part for the tool fixing. 4. By comparing the simulation results and the experimental test, the simulation model can be adjusted and got an accurate analytical model for further analysis of the spindle’s heat deformation under different speeds, and the method for spindle box temperature and thermal deformation based on FEM is feasible, which provides theory for futher thermal compensation under the model.