Strip rolling mill and strip rolling method

Abstract

To preferably roll a hard material or an ultra thin material by more reliably supporting small diameter work rolls even under a transient condition such as when starting a rolling operation or when finishing a rolling operation, undriven both ends support rolls 9, 10, 11 and 12 are provided on outer sides of a width along which a maximum sheet width of strip passes on a barrel portion of the work roll 3 , to be opposed to each other at an entry side and a delivery side of respective end portions to thereby press and support the work roll. Further, hydrostatic bearings 21 and 23 are installed at central portions of both side barrels of the work roll 3 , and fluid such as oil is supplied from fluid pressure supply ports 25 and 26 to the bearing portions to thereby float up the work rolls 3 by forming gaps between the hydrostatic bearings 21 and 23 and the work roll 3 and support the work roll 3 in horizontal direction in noncontact. By changing supply pressure of the fluid supplied to the hydrostatic bearings 21 and 23 , a proper float up amount and a support force can be set or controlled.

What is claimed is:  
     
         1 . A strip rolling mill comprising: 
 at least a pair of upper and lower work rolls for rolling strip;    at least a pair of backup rolls for supporting the work rolls in an up and down direction and providing a rolling drive force thereto;    at least pairs of both ends support rolls opposed to each other in a horizontal direction for pressing and sandwiching both end portions of the work rolls on outer sides of a width along which a maximum sheet width of the strip passes on barrel portions of the work rolls; and    hydrostatic bearings for supporting, by hydraulic pressure, at least either one of an entry side and a delivery side of centers of the barrel portions of the work rolls substantially in a horizontal direction.    
     
     
         2 . A strip rolling mill comprising: 
 at least a pair of upper and lower work rolls for rolling strip;    at least a pair of backup rolls for supporting the work rolls in an up and down direction and providing a rolling drive force thereto;    at least pairs of both ends support rolls opposed to each other in a horizontal direction for pressing and sandwiching both end portions of the work rolls on outer sides of a width along which a maximum sheet width of the strip passes on barrel portions of the work rolls; and    hydrostatic bearings for supporting, by hydraulic pressure via at least one or more of idle rolls, at least either one of an entry side and a delivery side of centers of the barrel portions of the work rolls substantially in a horizontal direction.    
     
     
         3 . The strip rolling mill according to    claim 1    or    claim 2   : 
 wherein a total support apparatus integrally formed by support portions for the both ends support rolls and support portions for the hydrostatic bearings are installed to be capable of adjusting the position of the work rolls in the horizontal direction at either one of the entry side and the delivery side of the work rolls as a reference side; and  
 wherein on opposed sides of the work rolls, as pressing side, the total support apparatus are installed to be capable of pressing the work rolls in the horizontal direction opposedly to the reference side.  
 
     
     
         4 . The strip rolling mill according to    claim 1    or    claim 2   : 
 wherein when supporting the work roll by the hydrostatic bearing, the work roll is supported on a side of receiving a load by rolling and on an opposed side, the work roll is supported in noncontact or slight contact with the hydrostatic bearing.  
 
     
     
         5 . The strip rolling mill according to any one of claims  1  through  4 , further comprising: 
 load detecting means provided at support portions for at least one of the both ends support rolls on at least one of the entry side and the delivery side and for at least one of the hydrostatic bearings.  
 
     
     
         6 . The strip rolling mill according to any one of claims  1  through  5 : 
 wherein the support force in the horizontal direction of the both ends support roll supporting portions on the reference side is controlled to be larger than a slip occurrence limit value between the work rolls and the both ends support rolls but to be smaller than a support limit value of the both ends support rolls; and  
 wherein the press force of the both ends support rolls on the pressing side is controlled to be larger than the slip occurrence limit value between the work rolls and the both ends support rolls and to be as large as possible within a range equal to or smaller than the support limit value of the both ends support rolls.  
 
     
     
         7 . The strip rolling mill according to any one of claims  1  through  6 , further comprising: 
 means for variably controlling an effective length of the hydrostatic bearing to be substantially the same as a sheet width of the strip.  
 
     
     
         8 . A strip rolling method of rolling strip by supporting the work rolls in the horizontal direction by means of the both ends support rolls and the hydrostatic bearings using the strip rolling mill according to    claim 1    or    2   .  
     
     
         9 . A strip rolling method of rolling strip by a pair of upper and lower work rolls, comprising the steps of: 
 pressing and sandwiching, by at least pairs of both ends support rolls opposed to each other in a horizontal direction, both end portions of the work rolls on outer sides of a width along which a maximum sheet width of the strip passes on barrel portions of the work rolls; and    supporting, by hydraulic pressure of hydrostatic bearings, at least either one of an entry side and a delivery side of centers of the barrel portions of the work rolls substantially in a horizontal direction.    
     
     
         10 . A strip rolling method of rolling strip, comprising the steps of: 
 rolling strip by a pair of upper and lower work rolls;    supporting the work rolls in an up and down direction and providing a rolling drive force at least by a pair of backup rolls;    pressing and sandwiching, by at least pairs of both ends support rolls opposed to each other in a horizontal direction, both end portions of the work rolls on outer sides of a width along which a maximum sheet width of the strip passes on barrel portions of the work rolls; and    supporting, by hydraulic pressure of hydrostatic bearings, at least either one of an entry side and a delivery side of centers of the barrel portions of the work rolls substantially in a horizontal direction.