Ultra-precision Grinding of the Complex Surfaces of Hydrodynamic Seal Rings Used in Reactor Coolant Pumps

Abstract

A novel method for ultra-precision grinding the complex surfaces of the hydrodynamic seal rings used in reactor coolant pumps is proposed.It uses a rotary table and a cup wheel to perform an infeed grindingo.Its principle is that the grinding contact arc is an approximation to the curve on the wavy surface bounded by its inner and outer peripheries if select suitable wheel radius,wheel pitch angle,wheel roll angle and the center distance between the wheel and the rotary table and the trajectory of the grinding contact arc can form the wavy surface by numerically controlling the rotation of the rotary table and the synchronous periodic motion of the rotary table or the cup wheel,and the flat dam surface can be generated if the two rotational axes are parallel.Micro infeed grinding with constant wheel depth of cut is adopt so that the form accuracy of the mechanical face seal is independent of the cup wheel wear but mainly depends on the motion accuracy of the rotary table and the cup wheel and the synchronous motion accuracy of the cup wheel.It is expected to be an efficient method to manufacture the complex surfaces of the hydrodynamic seal rings used in reactor coolant pumps with extremely high form accuracy and low surface roughness.