Ultra-precise processing method for circular conical surface of fluid static pressure sealing ring for nuclear primary pump

Abstract

The invention relates to an ultra-precise processing method for the circular conical surface of a fluid static pressure sealing ring for a nuclear primary pump, which belongs to the technical field of precise processing and is characterized in that the sealing ring is clamped in the center of a rotating work table, the radius of a cup-shaped grinding wheel is 75 to 250mm, the distance from the crossing point of the end surface of the cup-shaped grinding wheel and a rotating axis of the cup-shaped grinding wheel to a rotating axis of the rotating work table is 100 to 350mm, according to the principle that the taper error of the surface generated by the grinding is smaller than the given taper tolerance, an inclination angle of the rotating axis of the cup-shaped grinding wheel relative to the rotating axis of the rotating work table and an included angle between the rotating axis of the cup-shaped grinding wheel and a straight line are selected, wherein the straight line passes throughthe crossing point of the end surface of the cup-shaped grinding wheel and the rotating axis of the cup-shaped grinding wheel and is vertically intersected with the rotating axis of the rotating worktable. During grinding, the rotating work table and the cup-shaped grinding wheel do rotating movement, the cup-shaped grinding wheel feeds along the rotating axis of the rotating work table, and thecutting-in grinding is carried out by the end surface of the cup-shaped grinding wheel. The ultra-precise processing method has the effects and benefits that the machine tool structure is simple, andthe high-precise and low-surface-roughness grinding of the circular conical surface of the fluid static pressure sealing ring for the nuclear primary pump can be realized.

Description

technical field [0001] The invention belongs to the technical field of ultra-precision machining of conical surfaces of hydrostatic sealing rings for nuclear main pumps, and relates to the processing of mechanical sealing rings, in particular to an ultra-precision grinding method for conical surfaces of hydrostatic sealing rings for nuclear main pumps. Background technique [0002] Shaft-sealed nuclear main pumps mostly use hydrostatic mechanical seals that can withstand high pressure and heavy loads and have a long life to prevent leakage of radioactive coolant. The sealing principle is to process a conical surface with a very small inclination angle (0.00017-0.0007 radians) on the end face of the moving ring or the static ring, so as to generate a wedge-shaped convergence gap between the sealing interface composed of the moving ring and the static ring, which is formed by the hydrostatic pressure effect. The generated hydrostatic pressure balances the opening force and the...

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Problems solved by technology

[0003] When the conical surface of the hydrostatic sealing ring for the nuclear main pump is ground by the grinding wheel on the ordinary cylindrical grinder or the universal cylindrical grinding machine, the grinding wheel and the sealing ring are in surface contact, the grinding force is large, and the uneven wear of the grinding wheel end face is serious. It is impossible to process the conical surface of high-precision sealing ring

When the conical surface of the sealing ring is processed by a horizontal axis circular table surface grinder, the working part of the grinding wheel is the outer peripheral surface, and the axial width of the grinding wheel is generally smaller than the width of the sealing ring. Due to the low rotation speed of the round table, the grinding wheel needs a considerable number of revolutions to completely traverse the machined surface of the sealing ring once. The uneven wear of the working surface of the grinding wheel and the uniform wear in the radial direction will affect the grinding The surface shape accuracy of the generated surface, so the horizontal axis circular table surface grinder is not suitable for processing the conical surface of the hydrostatic seal ring for nuclear main pumps

When multi-axis linkage CNC grinding is used to process the conical surface of the sealing ring, the grinding wheel and the sealing ring are in point contact. There is a certain residual height between the movement paths of the cutting points of the grinding wheel, the grinding wheel wears quickly, and the shape retention of the grinding wheel is poor. The existing technology is not very good. Solve the problems of precise grinding wheel modification and grinding wheel wear compensation, and the machining accuracy is not easy to guarantee

The flat sealing ring surface is usually processed by grinding and polishing, but when the conical surface of the sealing ring is ground or polished, it is easy to produce sagging and convex defects

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