目前一般教科书,对于预紧联结组合结构大多采用不变刚度计算法。这种方法是按螺杆预紧时的刚度关系计算受外载变形的刚度关系。实际上压力机在外载作用下的新刚度关系与预紧时的刚度关系不同。本文按这种刚度变化关系分析预紧联接组合床身,计算螺杆受力和变形并校核疲劳强度。 The current general textbook, for the prestressed joint structure mostly rigid stiffness calculation method. This method is based on the relationship between the stiffness of the screw preload calculated by the stiffness of the relationship between the load deformation. In fact, the relationship between the new stiffness of the press under external load and the stiffness of the preload is different. In this paper, according to the relationship between the stiffness changes preload connection combined bed, calculate the screw force and deformation and check the fatigue strength.