预紧扁挤压筒内孔变形的研究

Research on deformation of inner cavity for shrink-fitting flatcontainer and corresponding structural improvement

扁挤压筒内层套壁厚变化大,过盈装配后使内腔发生不均匀变形而超过挤压筒规定的尺寸精度,给后续修模工作带来不便.因此,从扁挤压筒的结构改进着手,考虑几何相似性,采用外形呈椭圆状的扁挤压筒内层结构代替外形呈圆形的内层结构,应用ANSYS有限元分析软件,对两种受预紧作用的双层扁挤压筒分别进行数值模拟,研究其内孔变形规律,并用物理实验加以验证.结果表明:与采用圆形的内层结构相比,采用椭圆形状的内层结构其内孔变形量在整个圆周上分布较均匀,这为扁挤压筒修模工作带来了方便,同时也使模具的制造精度得到提高.

With great thickness transition of inner layer from major axis to minor axis, the inner cavity of shrink-fitting flat container would deform unevenly beyond the prescriptive dimension precision, which would put re-sinking of die into trouble. Thus, structure development of the flat container was put forward. Considering geometric similarity, an idea of using elliptic inner layer structure was presented instead of circular shape. The numerical simulations of two-layer flat containers with two kinds of structures respectively subjected to the shrink fitting were made by ANSYS finite element analytical software. The deformation law and displacement of inner cavity were analyzed. Then corresponding actual experiments were carried out to testify them. Finally, the results indicated that displacement on the straight edge of inner cavity using elliptic structure is smaller than that using circular structure. Moreover, the deformation distribution of the former is more even than that of the latter on the whole cavity die. All these gave convenience to re-sinking of die and improved the manufacturing accuracy of parts.