Rolling mill laying head

Abstract

Aspects of the present invention relate to a rolling mill laying head. The rolling mill laying head comprises a quill rotatable about a central axis, said quill being equipped with a guide pathway configured and arranged to form a longitudinally moving product into a continuous series of rings; a stationary support structure; and axially spaced radial bearings supporting said quill for rotation about said axis, one of said bearings comprising a hydrostatic oil film bearing having an internal diameter of at least about 500 mm, and having a L/D ratio less than 0.25.

1 . A rolling mill laying head comprising:
 a quill rotatable about a central axis, said quill being equipped with a guide pathway configured and arranged to form a longitudinally moving product into a continuous series of rings;   a stationary support structure; and   axially spaced radial bearings supporting said quill for rotation about said axis, one of said bearings comprising a hydrostatic oil film bearing having an internal diameter of at least about 500 mm, and having a L/D ratio less than 0.25.   
     
     
         2 . The laying head of  claim 1  wherein said L/D ratio is between 0.25 and 0.15. 
     
     
         3 . The laying head of  claim 1  wherein said hydrostatic oil film bearing comprises a bushing surrounding a journal surface of said quill, a plurality of angularly separated recesses in said bushing, and a primary supply means for supplying oil at an elevated pressure to said recesses via a supply header to thereby create discrete pressure fields acting on said journal surface to urge said quill into concentric alignment with said bushing. 
     
     
         4 . The laying head of  claim 3  wherein at least three of said recesses and associated pressure fields are provided in said bushing. 
     
     
         5 . The laying head of  claim 3  wherein said recesses are equally spaced around the circumference of said bushing. 
     
     
         6 . The laying head of  claim 3  further comprising an auxiliary supply means for supplying high pressure oil to said hydrostatic bearing in the event of an interruption in the supply of oil by said primary supply means. 
     
     
         7 . The laying head of  claim 6  wherein said auxiliary supply means comprises an accumulator charged with high pressure oil by said primary supply means. 
     
     
         8 . A rolling mill laying head comprising:
 a quill rotatable about a central axis, said quill being equipped with a guide pathway configured and arranged to form a longitudinally moving product into a continuous series of rings;   a stationary support structure;   axially spaced radial bearings supporting said quill for rotation about said axis, one of said bearings comprising a hydrostatic oil film bearing having an internal diameter of at least about 500 mm, and having a L/D ratio less than 0.25, said hydrostatic oil film bearing comprising a bushing surrounding a journal surface of said quill, with at least three angularly separated recesses in said bushing, and with a primary supply means for supplying oil at an elevated pressure to said recesses via a supply header to thereby create discrete pressure fields acting on said journal surface to urge said quill into concentric alignment with said bushing, and an auxiliary supply means for supplying high pressure oil to said hydrostatic bearing in the event of an interruption in the supply of oil by said primary supply means.   
     
     
         9 . The laying head of  claim 4  wherein said recesses are equally spaced around the circumference of said bushing.