现有周期式冷轧管机的工作辊辊身是圆柱形的,沿其长度具有变断而的螺旋形轧槽。这种轧辊辊身外表面的曲率半径为常数,而轧槽深度是变化的。因此,这种轧辊的滚轧半径,即由作相对运动的轧辊旋转轴线至其瞬时滚动中心的距离是变化的,它与轧辊传动装置的主动齿轮恒定半径不相等。因此,使用这种轧辊会在管坯祀管子中产生很大的轴向力,这种轴向力可使管坯和芯棒顶杆失去稳定性,从而在轧制过程中造成带芯棒的管子断裂。这会使成品管质量变坏,并降低孔型的使用寿命,造成 The work roll barrel of the existing periodic cold rolling mill is cylindrical and has a discontinuous spiral groove along its length. The radius of curvature of the outer surface of the roll barrel is constant and the groove depth varies. Therefore, the rolling radius of such rolls, i.e., the distance from the axis of rotation of the relative moving rolls to their instantaneous roll center, varies with a constant radius of the drive gear of the roll drive. Therefore, the use of such a roll will produce a significant axial force in the tube. This axial force may destabilize the tube blank and the mandrel mandrel, resulting in a cored Tube broken. This will deteriorate the finished pipe quality and reduce the service life of the hole type