Method of producing shaped steel changing in cross-sectional shape in longitudinal direction and roll forming apparatus for same

Patent metadata

Field	Value
Publication number	US-9878360-B2
Application number	US-201315025488-A
Country	US
Kind code	B2
Filing date	Oct 18, 2013
Priority date	Oct 18, 2013
Publication date	Jan 30, 2018
Grant date	Jan 30, 2018

Abstract

A roll forming apparatus for roll forming for producing from a sheet material a shaped steel which varies in cross-sectional shape in a longitudinal direction comprises a first rolling die which has an annular ridge part which varies in cross-sectional shape in a circumferential direction; a second rolling die which has an annular groove part which varies in cross-sectional shape in a circumferential direction; and a drive device for the first rolling die and the second rolling die. At least transition parts of the side surfaces of the annular ridge part of the first rolling die are provided with relief so that the gap with respect to the side surfaces of the annular groove part of the second rolling die becomes broader inward in the radial direction.

First claim

The invention claimed is:

1. A method of producing a shaped steel which varies in cross-sectional shape in a longitudinal direction from a sheet by roll forming, comprising:
a step of preparing a first rolling die which has a rotation shaft and an annular ridge part which varies in cross-sectional shape in a circumferential direction which is centered about said rotation shaft;
a step of arranging said first rolling die so that the rotation shaft of said first rolling die becomes perpendicular to a sheet feed direction;
a step of preparing a second rolling die which has a rotation shaft and an annular groove part which varies in cross-sectional shape in a circumferential direction which is centered about said rotation shaft;
a step of arranging said second rolling die so that a gap which is equal to a thickness of said sheet is formed between said first rolling die and second rolling die and the annular ridge part of said first rolling die and the annular groove part of said second rolling die engage;
a step of making said first rolling die and said second rolling die rotate synchronized; and
a step of feeding the sheet between said first rolling die and second rolling die,
wherein side surfaces of the annular ridge part of said first rolling die are provided with a relief so that the gap with respect to side surfaces of the annular groove part of the second rolling die broadens over at least part of the circumferential direction and at an inner side in a radial direction of said first rolling die,
wherein said annular ridge part of said first rolling die is configured so that the relative angle between a ridgeline and the rotation direction of said first rolling die varies at least partially in the circumferential direction, and
wherein the relief amount at said relief is set to vary in accordance with the relative angle between the ridgeline of the annular ridge part of said first rolling die and the rotation direction of said first rolling die.

2. The method of production of a shaped steel according to claim 1 , wherein the larger said relative angle, the larger said relief amount is made.

3. The method of production of a shaped steel according to claim 1 , wherein said annular ridge part of said first rolling die is configured so that a height dimension which is measured in a perpendicular direction with respect to said rotation shaft varies at least partially in the circumferential direction, and in that said relief amount is made larger the higher the height of said annular ridge part.

4. The method of production of a shaped steel according to claim 1 , wherein said shaped steel is a hat-shaped steel with an inner circumferential surface which is rolled by the annular ridge part of said first rolling die and with an outer circumferential surface which is rolled by the annular groove part of the second rolling die.

5. The method of production of a shaped steel according to claim 1 , wherein the annular ridge part of said first rolling die includes, in its circumferential direction, a first roll width region, a second roll width region, and a tapered region which increases or decreases in width from said first roll width to second roll width.

6. The method of production of a shaped steel according to claim 1 , wherein said first rolling die has the annular ridge part which is offset in the rotation shaft direction in its circumferential direction and produces a shaped steel having stock axis which is curved in the width direction.

7. The method of production of a shaped steel according to claim 1 , wherein the relief amount x of the side surfaces of said first rolling die is set to not less than a value x′ which is calculated by the following formula (1):
x′=α×H/R ×tan θ×|tan φ|  (1)

where a height of the annular ridge part is “H”, a roll diameter of said first rolling die is “R”, a inclination angle of the side walls of the shaped steel is “θ”, a relative angle between said ridgeline and rotation direction is “φ”, and α is a constant.

8. The method of production of a shaped steel according to claim 7 , wherein a plurality of roll units each of which comprises first rolling dies and second rolling dies are arranged in series in a sheet feed direction and the material is bent by these plurality of roll units so that the side wall angle θ is increased in stages, and in that the relief amount x of the side surfaces of the first rolling die of part or all of the roll units is not less than a value which is calculated by the formula (1).

9. The method of production of a shaped steel according to claim 1 , wherein the relief which is provided at the side surfaces of the annular ridge part of said first rolling die is started separated from the ridgeline of said annular ridge part by a predetermined length L and said predetermined length L is set so that, when the height of said annular ridge part is “H”, 0<L/H≦0.4.

10. The method of production of a shaped steel according to claim 1 , wherein an outside diameter of the annular ridge part of said first rolling die and an outside diameter of the bottom surface part of the annular groove part of the second rolling die are the same.

11. The method of production of a shaped steel according to claim 1 , wherein the material of said shaped steel is ultra high tensile steel.

12. A roll forming apparatus for roll forming for producing a shaped steel which varys in cross-sectional shape in a longitudinal direction from a sheet, comprising:
a first rolling die which has a rotation shaft and an annular ridge part which varies in cross-sectional shape in a circumferential direction which is centered about said rotation shaft, said first rolling die arranged so that the rotation shaft of said first rolling die becomes perpendicular to a sheet feed direction;
a second rolling die which has a rotation shaft and an annular groove part which varies in cross-sectional shape in a circumferential direction which is centered about said rotation shaft, said second rolling die arranged so that said rotation shaft of said second rolling die becomes parallel to said rotation shaft of said first rolling die; and
a drive device which synchronizes and rotationally drives said first rolling die and said second rolling die,
wherein said first rolling die and second rolling die are arranged relatively so that a gap which is equal to a thickness of said sheet is formed between the two and the annular ridge part of said first rolling die and the annular groove part of said second rolling die engage,
wherein side surfaces of the annular ridge part of said first rolling die are provided with a relief so that the gap with respect to side surfaces of the annular groove part of the second rolling die broadens over at least part of the circumferential direction and at an inner side in a radial direction of said first rolling die,
wherein said annular ridge part of said first rolling die is configured so that the relative angle between a ridgeline and the rotation direction of said first rolling die varies at least partially in the circumferential direction, and
wherein the relief amount at said relief is set to vary in accordance with the relative angle between the ridgeline of the annular ridge part of said first rolling die and the rotation direction of said first rolling die.

13. The roll forming apparatus according to claim 12 , wherein the larger said relative angle, the larger said relief amount is made.

14. The roll forming apparatus according to claim 12 , wherein said annular ridge part of said first rolling die is configured so that a height dimension which is measured in a perpendicular direction wit

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Kubo Masahiro
• Yoshida Hiroshi
• Mizumura Masaaki
• Daimaru Seiichi

Classifications

• B21D5/083 Primary

  for obtaining profiles with changing cross-sectional configuration · CPC title