我厂 1 9mm× 2 0 0 0 mm三辊对称型卷板机 ,由于卷板时操作不当 ,一支承座突然断裂 ,如图 1所示。经计算 ,卷板机满负荷时断口处所承受的水平拉力为 72 5 k N。由于下辊的正反交变旋转 ,造成支承座承受交变载荷以及启动时的突然冲击力。在交变载荷的作用下 ,于应力集中的直角 I plant 1 9mm × 2 0 0 mm three-roll symmetrical bending machine, due to improper operation of the coil, a seat suddenly broken, as shown in Figure 1. It is calculated that the horizontal pull force sustained by the fracture at the full load of the bending machine is 72 5 kN. Due to the positive and negative rotation of the lower roller, resulting in bearing seat to withstand alternating loads and sudden impact on startup. In the alternating load, the stress concentration of the right angle