Roller leveler and sheet-material flattening method

Abstract

A roller leveler for flattening sheet material includes: a leveling roll unit that has a plurality of leveling rolls configured to rotate so as to pass the sheet material while sandwiching and pressing the sheet material interposed therebetween; pushing cylinders configured to press the sheet material via the leveling rolls and provided on each of an entrance side and a discharge side of the leveling roll unit, on which the sheet material enters and is discharged into and from the leveling roll unit, respectively; and a driving mechanism configured to rotate the leveling rolls to pass the sheet material, wherein the plurality of leveling rolls are designed so that a diameter thereof satisfies a relation, 0.5<D/P<0.9, in relation to a roll pitch P of the leveling rolls that is determined from a maximum requirement yield stress and a maximum requirement sheet-material thickness of the sheet material to be flattened.

1 . A roller leveler for flattening sheet material by passing the sheet material through a pass line, comprising:
 a leveling roll unit that has a plurality of leveling rolls arranged on upper and lower sides of the pass line in a staggered manner and configured to rotate so as to pass the sheet material while flattening the sheet material interposed therebetween;   a pushing cylinder configured to press the sheet material via the leveling rolls and provided on each of an entrance side and a discharge side of the leveling roll unit, on which the sheet material enters and is discharged into and from the leveling roll unit, respectively;   a plurality of backup rolls that back up the leveling rolls; and   a driving mechanism configured to rotate the leveling rolls to pass the sheet material, wherein   the plurality of leveling rolls are designed so that a diameter D thereof satisfies a relation, 0.5<D/P<0.9, in relation to a roll pitch P of the leveling rolls that is determined from a maximum requirement yield stress and a maximum requirement sheet-material thickness of the sheet material.   
     
     
         2 . The roller leveler according to  claim 1 , further comprising
 a control unit that is configured to control an amount of pressing of the sheet material performed by the pushing cylinder so that the sheet material is caught between the upper and lower leveling rolls of the leveling roll unit, wherein   the control unit has a catch correction table, in which a catch limit pressing amount and a catch correction control distance depending on thickness of the sheet material are entered, the catch limit pressing amount being a pressing amount, at or under which the sheet material is caught between the upper and lower leveling rolls of the leveling roll unit, the catch correction control distance being an amount of travel of a leading edge of the sheet material, at which the pressing amount should be brought to the catch limit pressing amount, and   the control unit is configured so that when a specified pressing amount, required to flatten the sheet material, of the pushing cylinder on the entrance side is greater than the catch limit pressing amount, the control unit performs control based on the catch correction table so that the pressing amount of the pushing cylinder on the entrance side is limited to the catch limit pressing amount until the leading edge of the sheet material reaches the catch correction control distance and, when the leading edge of the sheet material reaches the catch correction control distance, the pressing amount of the pushing cylinder on the entrance side is brought to the specified pressing amount.   
     
     
         3 . The roller leveler according to  claim 2 , wherein pressing speed, at which the pressing amount of the pushing cylinder on the entrance side is brought to the specified pressing amount when the leading edge of the sheet material reaches the catch correction control distance, is entered in the catch correction table, and wherein the control unit controls the pressing speed, at which the pressing amount of the pushing cylinder on the entrance side is changed from the catch limit pressing amount to the specified pressing amount, based on the catch correction table. 
     
     
         4 . A roller leveler for flattening sheet material by passing the sheet material through a pass line, comprising:
 a leveling roll unit that has a plurality of leveling rolls arranged on upper and lower sides of the pass line in a staggered manner and configured to rotate so as to pass the sheet material while flattening the sheet material interposed therebetween;   a plurality of backup rolls that back up the plurality of leveling rolls from upper and lower sides;   a pair of roll frames that support the leveling rolls and the backup rolls from upper and lower sides;   a pair of frames that support the pair of roll frames from upper and lower sides;   a pushing cylinder provided on each of an entrance side and a discharge side, at which the sheet material enters and is discharged into and from the leveling roll unit, respectively, and configured to push a working frame, which is one of the pair of frames, toward the pass line so as to press the sheet material between the leveling rolls via a corresponding one of the pair of roll frames;   a driving mechanism configured to rotate the leveling rolls;   a plurality of hydraulic crowning cylinders installed so as to be lined up in a width direction perpendicular to a direction, in which the sheet material is passed, between the working frame and the corresponding one of the pair of roll frames; and   a control unit that controls flattening of the sheet material, wherein   the plurality of leveling rolls are designed so that a diameter D thereof satisfies a relation, 0.5<D/P<0.9, in relation to a roll pitch P of the leveling rolls that is determined from a maximum requirement yield stress and a maximum requirement sheet-material thickness of the sheet material, and   the control unit is configured to perform control so that the sheet material is passed between the leveling rolls via the driving mechanism while controlling an amount of pressing performed by the pushing cylinders, and is also configured to perform tightening control, in which amounts of lateral deflection of the pair of frames in the width direction are determined, a required amount of tightening of each of the hydraulic crowning cylinders that is required to compensate for the amounts of lateral deflection is calculated, and tightening of each of the hydraulic crowning cylinders is controlled based on the required amount of tightening.   
     
     
         5 . The roller leveler according to  claim 4 , wherein, based on information on compressive deformation of the pushing cylinders, the hydraulic crowning cylinders, the pair of roll frames, the backup rolls, and the leveling rolls, the control unit calculates a required amount of tightening of each of the hydraulic crowning cylinders that is required to compensate for the compressive deformation and performs the tightening control of each of the hydraulic crowning cylinders based on a total value obtained by summing both this required amount of tightening and the required amount of tightening that is required to compensate for the amounts of lateral deflection of the pair of frames. 
     
     
         6 . The roller leveler according to  claim 4 , wherein the control unit has a catch correction table, in which a catch limit pressing amount and a catch correction control distance depending on thickness of the sheet material are entered, the catch limit pressing amount being a pressing amount, at or under which the sheet material is caught between the upper and lower leveling rolls of the leveling roll unit, the catch correction control distance being an amount of travel of a leading edge of the sheet material, at which the pressing amount should be brought to the catch limit pressing amount, and
 the control unit is configured so that when a specified pressing amount, required to flatten the sheet material, of the pushing cylinder on the entrance side is greater than the catch limit pressing amount, the control unit performs control based on the catch correction table so that the pressing amount of the pushing cylinder on the entrance side is limited to the catch limit pressing amount until the leading edge of the sheet material reaches the catch correction control distance and, when the leading edge of the sheet material reaches the catch correction control distance, the pressing amount of the pushing cylinder on the entrance side is brought to the specified pressing amount.   
     
     
         7 . The roller leveler according to  claim 6 , wherein pressing speed, at which the pressing amount of the pushing cylinder on the entrance side is brought to the specified pressing amount when the leading edge of the sheet material reaches the catch correction control distance, is entered in the catch correction table, and wherein the control unit controls the pressing speed, at which the pressing amount of the pushing cylinder on the entrance side is changed from the catch limit pressing amount to the specified pressing amount, based on the catch correction table. 
     
     
         8 . The roller leveler according to  claim 1 , wherein the diameter D and the pitch P satisfy a relation, 0.55<D/P<0.8. 
     
     
         9 . The roller leveler according to  claim 1 , wherein the driving mechanism includes: an upper leveling roll-driving section that has upper leveling roll-driving motors for driving the upper leveling rolls and upper leveling roll power-transmitting part for transmitting power of the upper leveling roll-driving motors to the upper leveling rolls; and a lower leveling roll-driving section that has lower leveling roll-driving motors for driving the lower leveling rolls and lower leveling roll power-transmitting part for transmitting power of the lower leveling roll-driving motors to the lower leveling rolls, wherein the upper leveling roll power-transmitting part and the lower leveling roll power-transmitting part are disposed so as not to interfere with each other. 
     
     
         10 . The roller leveler according to  claim 9 , wherein the upper leveling roll power-transmitting part is a universal spindle that includes: a first upper cross-pin unit connected to the upper leveling roll-driving motor side; a second upper cross-pin unit connected to a protruding portion of a shaft of each of the upper leveling rolls; and an intermediate shaft connecting the first and second upper cross-pin units, wherein the lower leveling roll power-transmitting part is a universal spindle that includes: a first lower cross-pin unit connected to the lower leveling roll-driving motor side; a second lower cross-pin unit connected to a protruding portion of a shaft of each of the lower leveling rolls; and an intermediate shaft connecting the first and second lower cross-pin units, and wherein a length of the protruding portion of the shaft of each of the upper leveling rolls and a length of the protruding portion of the shaft of each of the lower leveling rolls differ from each other so that the second upper cross-pin unit and the second lower cross-pin unit do not interfere with each other. 
     
     
         11 . (canceled) 
     
     
         12 . A sheet-material flattening method of flattening sheet material via a roller leveler for flattening the sheet material by passing the sheet material through a pass line, wherein
 the roller leveler includes:   a leveling roll unit that has a plurality of leveling rolls arranged on upper and lower sides of the pass line in a staggered manner and configured to rotate so as to pass the sheet material while flattening the sheet material interposed therebetween;   a plurality of backup rolls that back up the plurality of leveling rolls from upper and lower sides;   a pair of roll frames that support the leveling rolls and the backup rolls from upper and lower sides;   a pair of frames that support the pair of roll frames from upper and lower sides;   a pushing cylinder provided on each of an entrance side and a discharge side, at which the sheet material enters and is discharged into and from the leveling roll unit, respectively, and configured to push a working frame, which is one of the pair of frames, toward the pass line so as to press the sheet material between the leveling rolls via a corresponding one of the pair of roll frames;   a driving mechanism configured to rotate the leveling rolls; and   a plurality of hydraulic crowning cylinders installed so as to be lined up in a width direction perpendicular to a direction, in which the sheet material is passed, between the working frame and the corresponding one of the pair of roll frames, the method comprising:   determining a roll pitch P of the plurality of leveling rolls from a maximum requirement yield stress and a maximum requirement sheet-material thickness of the sheet material to be flattened;   setting a value of diameter D of the plurality of leveling rolls so as to satisfy a relation, 0.5<D/P<0.9;   determining amounts of lateral deflection of the pair of frames in the width direction;   calculating an amount of tightening of each of the hydraulic crowning cylinders that is required to compensate for the amounts of lateral deflection; and   controlling tightening of each of the hydraulic crowning cylinders based on the required amount of tightening.   
     
     
         13 . The sheet-material flattening method according to  claim 12 , further comprising:
 based on information on compressive deformation of the pushing cylinders, the hydraulic crowning cylinders, the pair of roll frames, the backup rolls, and the leveling rolls, calculating a required amount of tightening of each of the hydraulic crowning cylinders that is required to compensate for the compressive deformation; and   controlling tightening of each of the hydraulic crowning cylinders based on a total value obtained by summing both this required amount of tightening and the required amount of tightening that is required to compensate for the amounts of lateral deflection of the pair of frames.   
     
     
         14 . The sheet-material flattening method according to  claim 12 , wherein, based on a catch correction table, in which a catch limit pressing amount and a catch correction control distance depending on thickness of the sheet material are entered, the catch limit pressing amount being a pressing amount, at or under which the sheet material is caught between the upper and lower leveling rolls of the leveling roll unit, the catch correction control distance being an amount of travel of a leading edge of the sheet material, at which the pressing amount should be brought to the catch limit pressing amount, the following are further performed:
 limiting the pressing amount of the pushing cylinder on the entrance side to the catch limit pressing amount until the leading edge of the sheet material reaches the catch correction control distance when a specified pressing amount, required to flatten the sheet material, of the pushing cylinder on the entrance side is greater than the catch limit pressing amount; and   bringing the pressing amount of the pushing cylinder on the entrance side to the specified pressing amount when the leading edge of the sheet material reaches the catch correction control distance.   
     
     
         15 . The sheet-material flattening method according to  claim 14 , further comprising: entering into the catch correction table pressing speed, at which the pressing amount of the pushing cylinder on the entrance side is brought to the specified pressing amount when the leading edge of the sheet material reaches the catch correction control distance; and controlling the pressing speed, at which the pressing amount of the pushing cylinder on the entrance side is changed from the catch limit pressing amount to the specified pressing amount, based on the catch correction table. 
     
     
         16 . The sheet-material flattening method according to  claim 12 , wherein the diameter D and the pitch P satisfy the relation, 0.55<D/P<0.8.