Multiple-Winding Pipe Forming Device and Multiple-Winding Pipe Forming Method

Abstract

A multiple-winding pipe forming device for forming a wound pipe, the multiple-winding pipe forming device comprising: a plurality of pairs of forming rollers curling a metal sheet and winding the metal sheet into a roll shape; and a mandrel fabricated of metal, the mandrel including: a shaft disposed inside the metal sheet wound in the roll shape, one end side of the shaft being retained, which one end side is disposed upstream in a feeding direction of the metal sheet, and a working portion including a taper portion that increases in diameter from upstream to downstream in the feeding direction, wherein the taper portion is disposed at a position at which the metal sheet wound in the roll shape is sandwiched by, of the plurality of pairs of forming rollers, a pair of the forming rollers that is disposed at a downstream side in the feeding direction.

1 . A multiple-winding pipe forming device for forming a wound pipe, the multiple-winding pipe forming device comprising:
 a plurality of pairs of forming rollers arranged along a feeding direction of a metal sheet that is an object of forming, each pair of forming rollers opposing one another so as to sandwich the metal sheet, and the plurality of pairs of forming rollers curling the metal sheet and winding the metal sheet into a roll shape; and   a mandrel fabricated of metal, the mandrel including:   a shaft that extends in the feeding direction and is disposed inside the metal sheet wound in the roll shape, one end side of the shaft being retained, which one end side is disposed upstream in the feeding direction, and   a working portion provided at an opposite end side of the shaft from a side thereof at which the one end side is disposed, the working portion including a taper portion that increases in diameter from upstream to downstream in the feeding direction,   wherein the taper portion of the working portion is disposed at a position at which the metal sheet wound in the roll shape is sandwiched by, of the plurality of pairs of forming rollers, a pair of the forming rollers that is disposed at a downstream side in the feeding direction.   
     
     
         2 . The multiple-winding pipe forming device according to  claim 1 , wherein the working portion includes a circular rod portion protruding from an end of the taper portion to an opposite side of the taper portion from a side thereof at which the shaft is disposed, the circular rod portion being equal in diameter to the end of the taper portion. 
     
     
         3 . The multiple-winding pipe forming device according to  claim 1 , further comprising a moving apparatus that moves the mandrel along the feeding direction, the moving apparatus including:
 a retention portion that retains the one end side of the shaft and is movable to an upstream side and the downstream side in the feeding direction, and   a drive source that moves the retention portion.   
     
     
         4 . The multiple-winding pipe forming device according to  claim 3 , wherein the moving apparatus further includes:
 a sensor that, via the retention portion, detects tension acting on the shaft; and   a control section that, in accordance with a tension detected by the sensor, controls the drive source and adjusts a position of the retention portion along the feeding direction.   
     
     
         5 . A multiple-winding pipe forming method using the multiple-winding pipe forming device according to  claim 1 , the multiple-winding pipe forming method comprising:
 curling the metal sheet and winding the metal sheet into the roll shape; and   compressing superposed portions of the metal sheet wound in the roll shape between the taper portion of the working portion and the pair of forming rollers that is disposed at the downstream side in the feeding direction of the metal sheet.   
     
     
         6 . The multiple-winding pipe forming device according to  claim 2 , further comprising a moving apparatus that moves the mandrel along the feeding direction, the moving apparatus including:
 a retention portion that retains the one end side of the shaft and is movable to an upstream side and the downstream side in the feeding direction, and   a drive source that moves the retention portion.   
     
     
         7 . The multiple-winding pipe forming device according to  claim 6 , wherein the moving apparatus further includes:
 a sensor that, via the retention portion, detects tension acting on the shaft; and   a control section that, in accordance with a tension detected by the sensor, controls the drive source and adjusts a position of the retention portion along the feeding direction.