公开(公告)号：JPH08155555A

公开(公告)日：1996-06-18

申请号：JP32386194

申请日：1994-11-30

Applicant: SUMITOMO METAL IND

Inventor： AISAKA SHINICHIRO

IPC: B21D7/08

Abstract: PURPOSE: To suppress the dimensional fluctuation of a bending start part and bending end part by subjecting an indenting roll to indentation driving from a retreat position to a bending position and subjecting this indenting roll to retreat driving from the bending position to the retreat position in the state of feeding a pipe material. CONSTITUTION: The feeding of the pipe material is kept continued and the indentation driving of the indenting roll is executed when the bending start part arrives at the point of a bending roll. The retreat driving of the indenting roll is executed when the bending end part arrives at the point of the bending roll. The material feeding is executed at the time of the indentation operation of the indenting roll and at the time of the retreat operation thereof in such a manner, by which the straight part is stepwise shifted to the bent part in the bending start part of the material and the bent part is stepwise shifted to the straight part in the bending end part. As a result, the deformation of the bending in any parts is prevented and the dimensional fluctuation is suppressed to a lower level.

公开(公告)号：JPH11188409A

公开(公告)日：1999-07-13

申请号：JP35969897

申请日：1997-12-26

Applicant: SUMITOMO METAL IND

Inventor： AISAKA SHINICHIRO ,  OGAWA HIDENORI

IPC: B21B21/04 ,  B21C51/00

Abstract: PROBLEM TO BE SOLVED: To roll a material roll with the feed volume set at maximum without causing excessive feeding of the material pipe by judging an occurrence of excessive feeding of the material pipe from the fluctuation pattern of axial length stress to work on a mandrel and changing the feed volume the material pipe on the basis of the judged result. SOLUTION: A strain gauge SG is attached to a mandrel 4 and axial length stress is continuously measured, amplified with an amplifier 10, and then input to a judging circuit 12. To a crank shaft 3, a turning angle detector PG is installed, and each time a roll stand 2 makes one reciprocating motion in the given required time, the pulse signal is outputted to a gate setter 11. The gate setter 11 outputs the gate signal which is synchronized with this pulse signal, and preset to the judging correct 12. The judging circuit 12 operates an alarm 13 only when the signal inputted from the amplifier 10 is lower than the preset threshold. If the alarm 13 is operated, an operator decreases the feed volume of a material pipe SP, and when the alarm is not operated, the operator gradually increases the feed volume.

公开(公告)号：JPH09239451A

公开(公告)日：1997-09-16

申请号：JP5311196

申请日：1996-03-11

Applicant: SUMITOMO METAL IND

Inventor： AISAKA SHINICHIRO ,  KUBOKI TAKASHI ,  TAKAI TAKASHI

IPC: B21D7/025

Abstract: PROBLEM TO BE SOLVED: To provide a device capable of bending a tube having a same outside diameter and different radius of curvature with a same tool and the cold bending method capable of obtaining a U tube having the least possible variance in a radius of curvature of bent part. SOLUTION: A tube clamp means 7 to fix/hold a tube P to be worked is mounted on a drive turning table 2 at a variable position, further, a tube support means 12 consisting of paired grooved roll group 125 to hold the tube P to be worked movable in the longitudinal direction and to control a tube feed out speed is arranged on fixed frame 3 arranged in row on the drive turning table 2. By coinciding a tube feed out speed by the tube support means 12 with a turning speed of the tube clamp means 7, bending is executed. By this method, the U tube having reduced variance in a radius of curvature of bent part is produced.

公开(公告)号：JPH09239449A

公开(公告)日：1997-09-16

申请号：JP5049796

申请日：1996-03-07

Applicant: SUMITOMO METAL IND

Inventor： KUBOKI TAKASHI ,  AISAKA SHINICHIRO ,  FURUKATA MUNEKATSU

IPC: B21D7/024 ,  B21D7/08

Abstract: PROBLEM TO BE SOLVED: To efficiently execute cold bending with an uniform bending radius over the whole circumference of bending part by setting a caliber roll at the position capable of obtaining the optimum off-set value at the bending start time and specifying the ratio of the turning velocity of a metal tube to the circumferential velocity of the caliber roll. SOLUTION: The optimum off-set value LR reduced in the variation of the radius of curvature is previously obtained, and a caliber roll most adacent to a clamp is set at the position capable of obtaining the optimum off-set value at the beginning start time. The ratio (the circumference velocity ratio η) shown by the expression of the turning velocity of metal tube R.Q and the circumference velocity of the caliber roll γe.ω is set

公开(公告)号：JPH07308720A

公开(公告)日：1995-11-28

申请号：JP13122394

申请日：1994-05-19

Applicant: SUMITOMO METAL IND

Inventor： AISAKA SHINICHIRO

IPC: B21D7/08

Abstract: PURPOSE:To suppress the ellipticity of a bending part within a specific range with respect to all the bending radiuses while preventing the occurrence of a surface flaw on a bent part in performing bending with different bending radiuses by a caliber roll with one caliber in three-roll bending of a tube. CONSTITUTION:The caliber diameter (d) of three caliber rolls 2a, 2b and 2c, are set to larger than the maximum value of the dispersion of the outside diameter of a tube stock 1. The upper limit of the caliber diameter (d), is set to 1.05 X nominal outside diameter. The center caliber roll 2b is displaced in the axial direction to the caliber rolls 2a and 2c on both sides. The bias quantity deltais set to