Importation Method of the Thermal Contact Characteristics of the Joint into the FEM Analysis

Although the significance of the thermal contact characteristics of joints in machine tools has been pointed out for a long time, the thermal contact resistance, that is one of major factors of the joints, has still many uncertain facts. Therefore the resistance was not considered or the empirical value of the resistance was used in the past analysis of the machine tool thermal deformation. Then it is difficult to say that the thermal characteristics of the machine tools can be analyzed exactly. Moreover few researches compared the analytical results with the experimental ones. Accordingly, in this research the method to incorporate the measured value of the thermal contact resistance into the FEM analysis is proposed to express the nonlinear temperature distribution near the joint and the validity of the proposal is considered with the experiment. The conclusions in this research are as follows. (1) The contact thermal conductivity element can be introduced to incorporate the measured thermal contact resistance. (2) λe and dc, those are main factors of the contact conductivity element, are determined uniquely by the thermal contact resistance R, and the nonlinear temperature distribution near the joint can be analyzed by FEM using the element.