Shaft for use with annular seal assembly and method of manufacturing same

Abstract

A structure and method of manufacturing an outer surface of a shaft avoids the creation of a preferential lead and thereby minimizes leakage through an annular seal assembly when such shaft is rotated or otherwise moved relative thereto during use. The outer circumferential surface of the shaft is formed having a plurality of relatively small irregularities that are evenly distributed thereabout. Such irregularities may be defined by relatively higher portions and relatively lower portions that are formed in an intersecting, cross hatched pattern or in a circumferentially extending undulating or oscillating pattern. To form the cross hatched pattern, an apparatus can be operated to engage the outer circumferential surface of the shaft in two sequential passes in opposite axial directions while the shaft is being rotated. To form the undulating pattern, an apparatus can be operated to engage the outer circumferential surface of the shaft in an axially reciprocating manner while the shaft is being rotated. By varying the feed rate of the apparatus, the rotational speed of the shaft, and the magnitude of the force applied by the apparatus against the outer circumferential surface of the shaft, the size, shape, and depth of the surface irregularities can be varied as desired.

1 - 16 . (canceled)  
     
     
         17 . A combined shaft and seal assembly comprising: 
 a shaft having an outer cylindrical surface defining an outer diameter, said outer surface having a plurality of irregularities provided thereon, said plurality of irregularities being arranged such that said outer surface has no preferential lead formed thereon; and    a seal assembly disposed about said shaft and having a flexible portion that resiliently engages said outer surface of said shaft.    
     
     
         18 . The combined shaft and seal assembly defined in  claim 17  wherein said plurality of irregularities are higher portions that extend above said outer diameter.  
     
     
         19 . The combined shaft and seal assembly defined in  claim 18  wherein higher portions vary from about an Rvk value of from about 3.0 micro-inches to about 40.0 micro-inches above said outer diameter.  
     
     
         20 . The combined shaft and seal assembly defined in  claim 17  wherein said plurality of irregularities are lower portions that extend below said outer diameter.  
     
     
         21 . The combined shaft and seal assembly defined in  claim 20  wherein lower portions vary from about an Rvk value of from about 3.0 micro-inches to about 40.0 micro-inches below said outer diameter.