U.S. patent application number 14/485871 was filed with the patent office on 2015-01-01 for three-dimensionally bending machine, bending equipment line, and bent product.
The applicant listed for this patent is NIPPON STEEL & SUMITOMO METAL CORPORATION, SUMITOMO PIPE & TUBE CO., LTD.. Invention is credited to Fumihiko KIKUCHI, Shinjiro KUWAYAMA, Atsushi TOMIZAWA.
Application Number | 20150004430 14/485871 |
Document ID | / |
Family ID | 42666410 |
Filed Date | 2015-01-01 |
United States Patent
Application |
20150004430 |
Kind Code |
A1 |
TOMIZAWA; Atsushi ; et
al. |
January 1, 2015 |
THREE-DIMENSIONALLY BENDING MACHINE, BENDING EQUIPMENT LINE, AND
BENT PRODUCT
Abstract
A three-dimensionally bending machine comprises a supporting
unit to support a workpiece and a feeding unit to feed the
workpiece from an upstream side of the workpiece. A heating and
cooling unit, provided around the outer circumference of a portion
of the workpiece downstream of said supporting unit heats the
portion of workpiece in a temperature range for plastic deformation
and quenches and rapidly cools the deformed workpiece. A
three-dimensionally movable unit, provided downstream of said
heating and cooling unit, supports the metal material and controls
the supporting position and/or the moving speed of the metal
material to apply the bending moment in association with a feed
amount, a heating amount, and a cooling amount of the workpiece.
Even when a high-strength workpiece is bent, a workpiece having
excellent shape fixability and uniform hardness distribution can be
made, especially for application to sophisticated automobile
parts.
Inventors: |
TOMIZAWA; Atsushi; (Osaka,
JP) ; KIKUCHI; Fumihiko; (Tokyo, JP) ;
KUWAYAMA; Shinjiro; (Wakayama, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NIPPON STEEL & SUMITOMO METAL CORPORATION
SUMITOMO PIPE & TUBE CO., LTD. |
Tokyo
Ibaraki |
|
JP
JP |
|
|
Family ID: |
42666410 |
Appl. No.: |
14/485871 |
Filed: |
September 15, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12718390 |
Mar 5, 2010 |
8863565 |
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14485871 |
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11896319 |
Aug 31, 2007 |
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12718390 |
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PCT/JP2006/303220 |
Feb 23, 2006 |
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11896319 |
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Current U.S.
Class: |
428/603 ;
72/128 |
Current CPC
Class: |
B21D 7/162 20130101;
B21D 7/08 20130101; Y10T 428/1241 20150115; B21D 7/16 20130101;
B21D 7/165 20130101 |
Class at
Publication: |
428/603 ;
72/128 |
International
Class: |
B21D 7/16 20060101
B21D007/16; B21D 7/08 20060101 B21D007/08 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 3, 2005 |
JP |
2005-059571 |
Aug 24, 2005 |
JP |
2005-242441 |
Claims
1.-16. (canceled)
17. A bent product as being subjected to a thermomechanical
treatment by virtue of using a metal material bending machine,
having a tensile strength of 900 MPa or more, the metal material
bending machine comprising; a feeding unit for successively or
continuously feeding a workpiece from an upstream side of the
workpiece; a supporting unit for supporting the workpiece; a
heating and cooling unit that is provided around the outer
circumference of a portion of workpiece and is provided at a
downstream side of said supporting unit, both for use in heating a
portion of workpiece in a temperature range which allows the heated
portion to be locally plastically deformed and which allows
quenching to be performed, and for use in subsequently rapidly
cooling down the heated portion after a bending moment is applied
thereto; and a three-dimensionally movable unit that is provided at
the downstream side of said heating and cooling unit, for use in
clamping the workpiece, and controlling the clamping position
and/or the moving speed of the workpiece so as to apply the bending
moment in association with a feed amount of the workpiece by said
feeding unit and a heating amount and a cooling amount of the
workpiece by said heating and cooling unit.
Description
[0001] This is a continuation-in-part of U.S. application Ser. No.
11/896,319 filed Aug. 31, 2007, which is a continuation of
PCT/JP2006/303220 filed Feb. 23, 2006. The PCT application was not
in English as published under PCT Article 21(2).
TECHNICAL FIELD
[0002] The present invention relates to a bending machine, a
bending-equipment line, and more particularly, to a
three-dimensionally bending machine and a three-dimensionally
bending-equipment line, and to a bent product made by the
three-dimensionally bending machine or the three-dimensionally
bending-equipment line.
BACKGROUND ART
[0003] In recent years, demands for structural metal materials
having high strength and light weight have increased in
consideration of global environment. For example, in an automobile
industry, there are growing demands for the safety of car body, and
high-strength and light-weight parts of an automobile are
increasingly required, so that parts of an automobile have been
developed in order to improve fuel efficiency and collision
safety.
[0004] In order to meet these demands, a high strength steel sheet
having a much higher tensile strength than that in the prior art,
for example, a material having high strength with a tensile
strength of 780 MPa or more, preferably, 900 MPa or more, has come
into widespread use.
[0005] Meanwhile, while improving the strength of the steel sheet,
the conventional structures of parts of an automobile have been
reexamined. Following the above, there is a strong demand for the
development of an art for accurately bending a metal material in
any of various shapes, such as an art for two-dimensionally or
three-dimensionally bending a metal material in different
directions, in order to apply to various types of parts of an
automobile.
[0006] In order to meet the demands for the development of the
bending technology, various processing techniques have been
proposed. For example, Japanese Patent Application Publication No.
50-59263 and Japanese Patent No. 2816000 disclose a method for
bending a metal tube or the like while performing a thermal
treatment on the metal tube or the like. Specifically, the
following methods are disclosed: a bending method for clamping a
leading end of a metal tube or the like with a rotatable arm,
heating the metal tube or the like by using a heating unit,
appropriately moving the heated portion of the metal tube or the
like to bend the heated portion, and cooling down the bent portion
(Japanese Patent Application Publication No. 50-59263); and a
method for applying torsional and bending force to the heated
portion of the metal tube or the like to bend the metal tube or the
like while twisting the metal tube or the like (Japanese Patent No.
2816000).
[0007] However, the disclosed bending methods are so-called grab
bending methods requiring a rotatable arm for clamping the leading
end of a metal tube or the like, which makes it difficult to feed
the metal tube or the like to be bent at high speed. In addition,
the arm needs to make a return movement in order to repeatedly
clamp the metal tube or the like, resulting in a significant
variation in the feeding speed of the metal tube or the like.
Therefore, a complicated control is required for a heating or
cooling speed, which makes it difficult to ensure predetermined
quenching accuracy.
[0008] In order to solve the above-mentioned problems of the grab
bending method, Japanese Patent Application Publication No.
2000-158048 discloses a high-frequency heating bender based on push
bending that supports a push bending roller so as to be movable in
a three-dimensional direction. According to the high-frequency
heating bender disclosed in Japanese Patent Application Publication
No. 2000-158048, the push bending roller is swung around a
workpiece toward the opposite side of the workpiece, and comes into
contact with the opposite side of the workpiece, thereby bending
the workpiece. Therefore, in a two-dimensional continuous bending
operation in which a workpiece is two-dimensionally bent in
different directions in, for example, an S shape, a procedure of
turning the workpiece by 180 degrees is not needed.
[0009] However, in the high-frequency heating bender disclosed in
Japanese Patent Application Publication No. 2000-158048, since
there is no resort to clamp both side-faces of a workpiece to be
bent is not provided, the workpiece is likely to be deviated from
the intended shape due to the residual stress caused by a cooling
operation after the high-frequency heating. Therefore, it is
difficult to ensure predetermined dimensional accuracy, which makes
it difficult to improve the accuracy of bending, while restricting
the processing speed of the workpiece.
[0010] Further, Japanese Patent No. 3195083 discloses a
push-through bending machine that includes, instead of the push
bending roller of the high-frequency heating bender or the grab
bending method, a fixed die, a movable gyro die that is movable in
a three-dimensional direction, and a heating unit that heats a
metal member at a temperature according to the curvature of the
metal member to be formed by the movable gyro die.
[0011] In the bending machine disclosed in Japanese Patent No.
3195083, since either the movable gyro die or the fixed die does
not rotatably support a metal member to be bent, the surface
thereof is susceptible to seizure defects. In the bending machine
disclosed in Japanese Patent No. 3195083, a cooling fluid is
supplied to either the movable gyro die or the fixed die to prevent
the decrease in strength of dies and the deterioration of bending
accuracy due to their thermal expansion. However, Japanese Patent
No. 3195083 is not directed to perform a thermal treatment, such as
quenching, on the bent metal member, and thus it is difficult to
obtain a metal member having high strength.
DISCLOSURE OF THE INVENTION
[0012] As described above, a technique for bending a metal material
in various bending shapes to be applied to various parts of an
automobile is demanded in association with reassessing the
structures of the parts of an automobile. Meanwhile, it is
desirable that the metal material have a tensile strength of 900
MPa or more, preferably, 1300 MPa or more, in order to reduce the
weight of the metal material. In this case, a metal tube having a
tensile strength of about 500 to 700 MPa is bent as a starting
material and a thermal treatment is performed on the bent metal
tube to improve the strength of the metal tube, thereby obtaining a
metal material having high strength.
[0013] However, in the grab bending method disclosed in Japanese
Patent Application Publication No. 50-59263 and Japanese Patent No.
2816000, since the feeding speed of the metal tube varies
significantly, the cooling speed cannot be accurately controlled,
and a high degree of quenching accuracy cannot be ensured, which
makes it difficult to prevent the occurrence of uneven distortion.
As a result, variations in shape occur in for the bent metal
material, and delayed fracture occurs in the metal material having
high strength due to the residual stress. Thus, products made by
the grab bending method are not suitable for parts of an
automobile.
[0014] Further, the bending machine disclosed in Japanese Patent
No. 3195083 is based on push-through bending, but is not directed
to obtain a metal material having high strength by performing hot
working on a metal tube having low strength as a starting material
and then performing quenching on the heated metal tube to increase
the strength of the metal tube. In addition, the surface of the
movable gyro die is susceptible to seizure defects on due to the
heating of the metal tube. Therefore, the hot bending machine needs
to be further improved.
[0015] The invention is designed to solve the above-mentioned
problems, and it is an object of the present invention to provide a
bending machine and a bending equipment line to bend a metal
material with a high degree of operation efficiency, while the
method allowing a high degree of bending accuracy to be ensured
even when a metal material is bent in various shapes in association
with diversification of structures of automobile parts and further
even when a metal material having high strength is bent
likewise.
[0016] In order to achieve the object, according to an aspect of
the present invention, there is provided a three-dimensionally
bending machine comprising: a supporting unit for supporting a
metal material as a workpiece; a feeding unit for successively or
continuously feeding the workpiece from an upstream side of the
workpiece; a heating and cooling unit that is provided around the
outer circumference of a portion of the workpiece and at a
downstream side of said supporting unit, for use in heating a
portion of workpiece in a temperature range which allows the heated
portion of the workpiece to be plastically deformed and which
allows quenching to be performed, and for use in subsequently
rapidly cooling down the heated portion of the workpiece after a
bending moment is applied thereto; and a three-dimensionally
movable unit that is provided at the downstream side of said
heating and cooling unit, for use in clamping the workpiece and
controlling the supporting position and/or the moving speed of the
workpiece to apply the bending moment in association with a feed
amount of the workpiece by said feeding unit and a heating amount
and a cooling amount of the workpiece by said heating and cooling
unit.
[0017] That is, in the bending of a metal material as a workpiece,
the downstream side of the workpiece is supported, and a thermal
treatment is performed on the workpiece while moving the workpiece
at a predetermined speed, which makes it possible to ensure a
predetermined cooling speed. In addition, since the bent workpiece
is uniformly cooled down, it is possible to obtain a product having
excellent shape fixability despite high strength, and uniform
hardness.
[0018] For example, specifically, a blank tube of metal material as
a workpiece is successively and continuously heated by a
high-frequency heating coil at an A.sub.3 transformation point or
more and up to a temperature at which coarse grains are not
generated, and the locally heated portion of the workpiece is
plastically deformed by movable roller-dies. Then, a cooling medium
having water or oil as the main ingredient or other cooling fluids,
or otherwise, gas or mist is injected onto the outside surface or
both the outside and inside surface of the in-process tube, thereby
enabling to ensure a cooling speed of 100.degree. C./sec or
more.
[0019] In addition, the three-dimensionally movable unit functioned
to apply a bending moment clamps the workpiece in a rolling manner
to prevent seizure defects on the surface of dies, which makes it
possible to effectively bend the workpiece. Similarly, since the
supporting unit rotatably supports the workpiece, it is possible to
prevent seizure defects on the surface of the supporting unit.
[0020] According to a second aspect of the present invention,
preferably, the three-dimensionally movable unit includes at least
one of a shifting mechanism for moving the three-dimensionally
movable unit in a vertical direction, the one for moving the same
in a horizontal direction, a tilting mechanism for inclining the
same in a vertical plane, and the one for inclining the same in a
horizontal plane. According to this structure, even when the
workpiece is bent in various shapes, such as in a two-dimensional
continuous bending operation (for example, an S-shaped bending
operation) in which the workpiece is two-dimensionally bent in
different directions or a three-dimensional continuous bending
operation in which the workpiece is three-dimensionally bent in
different directions, it is possible to effectively perform
bending.
[0021] According to a third aspect of the present invention,
preferably, the three-dimensionally movable unit further includes a
moving mechanism for moving itself in the forward or backward
direction relative to the workpiece. According to this structure,
even when the bending radius of a metal product is small, it is
possible to ensure an appropriate arm length L, which makes it
possible to prevent an increase in the scale of a bending machine
and ensure a high degree of bending accuracy.
[0022] According to a fourth aspect of the present invention,
preferably, the heating and cooling unit include at least one of a
shifting mechanism for moving itself in a vertical direction, the
one for moving the same in a horizontal direction, a tilting
mechanism for inclining the same in a vertical plane, and the one
for inclining the same in a horizontal plane. According to this
structure, it is possible to synchronize the operation of the
three-dimensionally movable unit with that of the heating and
cooling unit, which makes it possible to perform much more accurate
and uniform bending.
[0023] According to a fifth aspect of the present invention,
preferably, the heating and cooling unit further include a moving
mechanism for moving the unit in the forward or backward direction
relative to the workpiece. According to this structure, it is
possible to heat the leading end of a metal tube at the beginning
of a bending operation, in addition to synchronization between the
operation of the three-dimensionally movable unit and that of the
heating and cooling unit. Therefore, it is possible to improve
workability and operability when mounting or dismounting a metal
tube.
[0024] According to a sixth aspect of the present invention,
preferably, the three-dimensionally movable unit includes a
rotating mechanism for rotating itself in a circumferential
direction. According to this structure, it is possible to twist the
workpiece, in addition to two-dimensionally or three-dimensionally
bending the workpiece in different directions.
[0025] According to a seventh aspect of the present invention,
preferably, a feeding unit provided at the upstream side of the
workpiece may include a mechanism that holds and rotates a
workpiece in a circumferential direction. According to this
structure, it is possible to twist the workpiece, in addition to
two-dimensionally or three-dimensionally bending the workpiece in
different directions, without using the rotating mechanism of the
three-dimensionally movable unit.
[0026] According to an eighth aspect of the present invention,
preferably, the supporting unit includes a rotating mechanism for
rotating itself in a circumferential direction in synchronization
with the rotation of the feeding unit. According to this structure,
for a torsional deformation of the workpiece, the rotating
mechanism of the feeding unit twists a rear end of the workpiece,
while synchronizing with the operation of the supporting unit,
without rotating the three-dimensionally movable unit in a
circumferential direction, which makes it possible to accurately
twist the workpiece. Alternatively the rotating mechanism of the
feeding unit may perform the relative twisting of the rear end of
the workpiece in synchronization with the operation of the
supporting unit, while independently rotating the
three-dimensionally movable unit in a circumferential direction. In
this case, it is also possible to accurately twist the
workpiece.
[0027] According to a ninth aspect of the present invention,
preferably, the three-dimensionally movable unit includes a driving
and rolling mechanism that drives rolls as roller-dies, such as a
driving motor that drives and rotates the rolls according to the
feed amount of the workpiece by the feeding unit That is, if the
three-dimensionally movable unit should not include the driving and
rolling mechanism, the rolls are driven by only frictional
resistance, and compressive stress is applied to the bent portion
of the workpiece, so that thickness of the inner radius side of the
bent portion increases, resulting in buckling. In particular, when
a thin workpiece is used, the buckling makes it difficult to bend
the thin workpiece, or may otherwise cause the accuracy of bending
to be deteriorated.
[0028] In contrast, the driving and rolling mechanism provided in
the three-dimensionally movable unit reduces the compressive stress
applied to the bent portion. In addition, when the revolving speed
of the roller-dies of the three-dimensionally movable unit is
controlled so as to be synchronized with the feed amount of the
workpiece fed through by the feeding unit, it is possible to apply
tensile stress to the bent portion and thus widen the available
range for bending. As a result, it is possible to improve the
bending accuracy of a workpiece.
[0029] According to a tenth aspect of the present invention,
preferably, the three-dimensionally movable unit may comprise two
roller-dies, three roller-dies, or four roller-dies.
[0030] According to an eleventh aspect of the present invention,
preferably the workpiece subjected to a bending operation is a
closed cross-section member, an open cross-section member, an
irregular cross-section member, or a rod member, wherein the
cross-section thereof is formed in various shapes. According to
this configuration, it is possible to design the roll caliber for
the three-dimensionally movable unit according to the cross-section
of a workpiece to be bent.
[0031] According to a twelfth aspect of the present invention,
preferably, one or more preheating units are provided at the
upstream side of the heating and cooling unit to perform two-stage
heating or preferential heating on the workpiece. According to this
aspect, when a preheating unit for plural-stage heating is used, it
is possible to disperse the heating load on the workpiece, thus
enabling to improve bending efficiency.
[0032] Meanwhile, when a preheating unit for preferential heating
is used, the temperature of the heated portion of the workpiece
intended to be an inner radius side of the bend is controlled to be
lower than that of the heated portion intended to be an outer
radius side of the bend, taking into account the bending direction
of the workpiece opted by the three-dimensionally movable unit.
When the heated portion of the workpiece is configured in this way,
it is possible to prevent wrinkles from being generated on the
inner radius surface of the bent portion and cracks from being
generated in the outer radius surface of the bent portion.
[0033] According to a thirteenth aspect of the present invention,
preferably, a mandrel, serving as the cooling means, is inserted
into the inside of the workpiece, and a cooling medium is supplied
by the mandrel alone and/or in combination with the cooling unit
provided around the outer circumference of the workpiece. According
to this feature, it is possible to ensure the cooling rate for,
particularly, a thick-wall workpiece.
[0034] According to a fourteenth aspect of the present invention,
preferably, an articulated robot having one or more joints is
provided, the joint each being able to rotate on its own axis
respectively, and the articulated robot performs the operation of
at least one of the shifting mechanism, the tilting mechanism, and
the moving mechanism of the three-dimensionally movable unit, and
the heating and/or cooling unit.
[0035] According to this feature, during the bending of a
workpiece, the articulated robot can perform on the basis of
control signals, a series of operations, each of which is effected
by a manipulator, such as a shifting operation in a vertical or
horizontal direction, a tilting operation in a vertical or
horizontal plane, and a moving operation in the forward or backward
direction, all of which are supposed to be carried out by the
three-dimensionally movable unit, the heating and cooling unit
respectively. Therefore, it is possible to improve the efficiency
of a bending operation and reduce the size of a bending
machine.
[0036] According to the present invention, in order to effectively
produce an inexpensive bent product from a round tube supplied as a
workpiece, a three dimensional-bending-equipment line includes: an
electric resistance welded steel tube production line that
includes: an uncoiler that continuously unrolls into a strip-shaped
steel sheet; a forming means that forms the unrolled strip-shaped
steel sheet into a steel tube having a predetermined shape in a
sectional view; a welding means that welds opposite side edges of
the strip-shaped steel sheets to form continuous tubular goods; and
a post-processing means that performs a weld bead cutting
operation, and, if necessary, a post-annealing operation or a
sizing operation; and the three-dimensionally bending machine
according to the above-mentioned aspect that is sequentially
disposed at the exit side of said electric resistance welded steel
tube manufacturing line.
[0037] According to the present invention, in order to effectively
produce an inexpensive bent product from an open cross-section
material supplied as a workpiece, a
three-dimensional-bending-equipment line includes: a roll forming
line that includes; an uncoiler that continuously unrolls into a
strip-shaped steel sheet; and a forming means that forms the
unrolled strip-shaped steel sheet into having a predetermined shape
in a sectional view; and the three-dimensionally bending machine
according to the above-mentioned aspect that is sequentially
disposed at the exit side of said roll forming line.
[0038] Further, a bent product of the invention is characterized in
that the product having a tensile strength of 900 MPa or more is
made by virtue of a thermomechanical treatment subjected during the
course when the bending machine as above is used.
[0039] According to the three-dimensionally bending machine, and
the three-dimensional-bending-equipment line in accordance with the
above-described aspects of the present invention, even when a
workpiece is bent in various shapes, such as in a two-dimensional
continuous bending operation in which the workpiece is
two-dimensionally bent in different directions (for example, an S
shape) or in a three-dimensional continuous bending operation in
which the workpiece is three-dimensionally bent in different
directions, and even when a workpiece having high strength is bent,
the workpiece is uniformly cooled down, whereby it is possible to
effectively obtain a metal product having excellent shape
fixability despite having high strength, and uniform hardness
distribution at a low cost.
[0040] Further, since the three dimensionally movable unit
rotatably clamps a workpiece, it is possible to retard the
generation of seizure defects on the surface of roller-dies in the
three-dimensionally movable unit. Therefore, the accuracy of a
bending operation can be ensured, and a bending operation can be
performed with a high degree of operation efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] FIG. 1 is a diagram illustrating the overall structure of a
three-dimensionally bending machine for performing a bending
operation according to the present invention.
[0042] FIGS. 2A and 2B are diagrams illustrating the
cross-sectional shapes of a workpiece that can be used as a
starting material according to the present invention. Specifically,
FIG. 2A shows a channel with an open cross section that is made by
roll forming, and FIG. 2B shows a channel with an irregular
cross-section that is made by an extrusion process.
[0043] FIGS. 3A and 3B are diagrams illustrating examples of the
structure of a supporting guide that can be used as a supporting
unit according to the present invention. Specifically, FIG. 3A
shows the cross-sectional structure of the supporting unit and a
rotational mechanism provided in the supporting unit, and FIG. 3B
is a perspective view illustrating the general appearance of the
supporting unit.
[0044] FIG. 4 is a diagram illustrating the structure of a main
part of the three-dimensionally bending machine according to the
present invention.
[0045] FIG. 5 is a diagram schematically illustrating an example of
the structure of a heating and cooling unit provided in the
three-dimensionally bending machine according to the present
invention.
[0046] FIG. 6 is a diagram illustrating the structure of a mandrel
that is inserted into a metal material as a workpiece having a
closed cross section (a metal tube) in order to ensure the cooling
rate even for a heavy-wall workpiece.
[0047] FIGS. 7(a) and 7(b) are diagrams illustrating a shifting
mechanism for movement in the vertical and horizontal directions, a
rotating mechanism for rotation in a circumferential direction of a
three-dimensionally movable unit (comprising rolls as roller-dies)
and a tilting mechanism for vertically and horizontally inclining
movements all of which are provided in the three-dimensionally
bending machine according to the present invention.
[0048] FIG. 8 is a diagram illustrating the operation of a moving
mechanism for movement in the forward or backward direction of the
three-dimensionally movable unit that is provided in the
three-dimensionally bending machine according to the present
invention.
[0049] FIGS. 9(a) to 9(c) are diagrams illustrating example
configurations of the three-dimensionally movable unit that is
provided in the three-dimensionally bending machine according to
the present invention. Specifically, FIG. 9(a) shows the
three-dimensionally movable unit having two rolls as roller-dies
when a workpiece is a member with a closed cross section, such as a
round tube, FIG. 9(b) shows the three-dimensionally movable unit
having two rolls when a workpiece is a member with a closed cross
section, such as a rectangular tube, or a member with an open cross
section, such as a channel, and FIG. 9(c) shows the
three-dimensionally movable unit having four rolls when a workpiece
is a member with a closed cross section, such as a rectangular
tube, or a member with an irregular cross section, such as a
channel.
[0050] FIG. 10 is a diagram illustrating the operation of a
preheating unit for performing preferential heating on a
workpiece.
[0051] FIG. 11 is a diagram illustrating the overall structure and
arrangement of an articulated robot that can be applied to the
three-dimensionally bending machine according to the present
invention.
[0052] FIG. 12 is a diagram illustrating another structural example
of the articulated robot that can be applied to the
three-dimensionally bending machine according to the present
invention.
[0053] FIG. 13 is a diagram illustrating the overall structure of
an electric resistance welded steel tube production line that can
be used to produce a workpiece.
[0054] FIG. 14 is a diagram illustrating the overall structure of a
roll forming line that can be used to produce a workpiece.
BEST MODE FOR CARRYING OUT THE INVENTION
[0055] Hereinafter, the overall configuration of a
three-dimensionally bending machine, an example structure of a
supporting unit, the structure of a feeding unit, an example
structure of a heating and cooling unit, the structure of a
three-dimensionally movable unit, the feature and operation of a
preheating unit, the structure and layout of an articulated robot,
and the characteristics of a three-dimensional-bending-equipment
line according to exemplary embodiments of the present invention
will be described with reference to the accompanying drawings.
[0056] 1. Overall Structure of Three-Dimensionally Bending Machine
and Example of Structure of Supporting Unit
[0057] FIG. 1 is a diagram illustrating the overall structure of a
three-dimensionally bending machine for performing a bending
operation according to the present invention. In the bending
method, a workpiece 1 as a starting material that is rotatably
supported by a supporting unit 2, is successively or continuously
fed from an upstream side, and is then bent at a downstream side of
the supporting unit 2.
[0058] The workpiece 1 made by metal material such as an alloy
shown in FIG. 1 has a circular shape (round tube) in a sectional
view, but the present invention is not limited thereto. Workpieces
having various shapes in a sectional view may be used. For example,
the following materials may be used as the workpiece 1: materials
with a closed cross section that have various shapes in a sectional
view including the circular shape (round tube) shown in FIG. 1, a
rectangular shape, a trapezoidal shape, and other complicated
shapes; materials (channels) with an open cross section that are
manufactured by, for example, roll forming; materials (channels)
with an irregular cross section that are produced by an extrusion
process; and rod-shaped materials having various shapes in,
sectional view (a circular rod, a rectangular rod, and an
irregular-shape rod).
[0059] FIGS. 2(a) and 2(b) are diagrams illustrating the
cross-sectional shapes of workpieces that can be used as the
starting materials according to the present invention.
Specifically, FIG. 2(a) shows a channel with an open cross section
that is manufactured by, for example, roll forming, and FIG. 2(b)
shows channels with an irregular cross section that are produced by
extruding. In the three-dimensionally bending machine according to
the present invention, it is necessary to design the shape of the
three-dimensionally movable unit or the supporting unit according
to the cross-sectional shape of the workpiece to be used.
[0060] The structure of the three-dimensionally bending machine
shown in FIG. 1 includes: two pairs of supporting units 2 for
rotatably supporting the workpiece 1; a feeding unit 3 that is
provided at the upstream side of the supporting unit 2 and
successively or continuously feeds the workpiece 1; and a
three-dimensionally movable unit 4 that is provided at the
downstream side of the two pairs of supporting unit 2, clamps the
workpiece 1, and controls the supporting position of the workpiece
1 and/or the moving speed thereof. The structure of the
three-dimensionally bending machine further includes: a
high-frequency induction heating coil 5 that is provided around the
outer circumference of the workpiece 1 on the entrance side of the
three-dimensionally movable unit 4, and locally heats a portion of
the workpiece 1; and a cooling unit 6 that rapidly cools down the
heated portion of the workpiece 1 to which bending moment is
applied.
[0061] In the three-dimensionally bending machine shown in FIG. 1,
since the workpiece having a circular shape (round tube) in a
sectional view is used, supporting rolls are used as the supporting
unit 2, but the present invention is not limited thereto. For
example, a supporting guide may be used according to the
cross-sectional shape of a workpiece used. In addition, as shown in
FIG. 1, two pairs of supporting rollers are used, but the number of
supporting rolls is not limited to two. For example, plural pairs
more than one or two pairs of supporting rollers may be used.
[0062] FIGS. 3(a) and 3(b) are diagrams illustrating examples of
the structure of a supporting guide that can be used as the
supporting unit according to the present invention. Specifically,
FIG. 3(a) shows the cross-sectional structure of the supporting
guide and a rotating mechanism provided in the supporting guide,
and FIG. 3(b) is a perspective view illustrating the general
appearance of the supporting guide 2. The supporting guide 2 shown
in FIG. 3 rotatively supports a rectangular tube 1, which is a
workpiece, and includes means for preventing the heating of the
supporting guide that is disposed close to the heating and cooling
unit (the high-frequency induction heating coil 5 shown in FIG. 1).
As means for preventing the heating of the supporting guide, it is
preferably to construct it using a non-magnetic material. In
addition, as shown in FIG. 3(b), the means for preventing the
heating of the supporting guide may be divided into two or more
segments, and attaching an insulating material, such as Teflon, to
the divided segments is effective to prevent the supporting guide
from being heated.
[0063] A rotating mechanism including a driving motor 10 and a
rotational gear 10a is directly connected to the supporting guide 2
such that the supporting guide 2 can be rotated in a
circumferential direction in synchronization with the rotation of
the feeding unit, which will be described in detail below.
Therefore, when the workpiece 1 is to be twisted, it is possible to
accurately deform the workpiece 1.
[0064] In the three-dimensionally bending machine according to the
present invention, the supporting rolls shown in FIG. 1 or the
supporting guide shown in FIG. 3 can be used as the supporting unit
for the workpiece 1. However, for the purpose of the consistency of
explanation, in the following a mode and an effect will be shown in
the case where a round tube is used as the workpiece, and the
supporting rolls are used as the supporting unit. In the present
invention, it goes without saying that, even when a rod-shaped
material or a material with a closed cross section, an open cross
section, or an irregular cross section is used instead of the round
tube, or even when the supporting guide is used as the workpiece
instead of the supporting rolls, the exactly same effect as
described above can be obtained.
[0065] 2. Structure of Processing Section and Structure of Each of
Heating and Cooling Unit.
[0066] FIG. 4 is a diagram illustrating the structure of a
processing core section of the three-dimensionally bending machine
according to the present invention. The two pairs of supporting
rolls 2 for supporting the workpiece 1 are provided, and the
three-dimensionally movable unit 4 is arranged at the downstream
side of the supporting rolls 2. In addition, the high-frequency
induction heating coil 5 and the cooling device 6 are arranged on
the entrance side of the three-dimensionally movable unit 4.
Further, a preheating unit 5a is provided between the two pairs of
supporting rolls 2, and a lubrication unit 8 for supplying a
lubricant is provided in close proximity to the entrance of the
three-dimensionally movable unit 4.
[0067] In the structure of the three-dimensionally bending machine
shown in FIG. 4, the three-dimensionally movable unit 4 clamps
workpiece 1 passing through the two pairs of supporting rolls 2,
and controls the supporting position and/or the moving speed
thereof. Then, the high-frequency induction heating coil 5 provided
around the outer circumference of the workpiece 1 locally heats and
bend a portion of the workpiece 1, followed by a subsequent rapid
cooling by means of the cooling device 6 provided around the outer
circumference of workpiece 1. During the bending operation, since
the high-frequency induction heating coil 5 heats workpiece 1 that
passes through the supporting rolls 2, the yield strength of the
portion of workpiece 1 to be bent by the three-dimensionally
movable unit 4 becomes low, and deformation resistance is lowered,
which makes it easy to bend the workpiece 1.
[0068] Furthermore, since the three-dimensionally movable unit 4
clamps workpiece 1 using movable rolls as roller-dies, it is
possible to retard the generation of seizure defects on the
surfaces of rolls despite clamping is done right after heating
workpiece 1. In addition, the lubricant is supplied to the
three-dimensionally movable unit. Therefore, even when scales
generated and came off from the heated portion of the workpiece 1
should get into the three-dimensionally movable unit, the lubricant
can prevent the generation of seizure defects on the surface of
rolls in the three-dimensionally movable unit.
[0069] In the three-dimensionally bending machine according to the
present invention, since a cooling fluid is supplied to the
three-dimensionally movable unit 4 to cool down the
three-dimensionally movable unit 4, it is possible to prevent the
decrease of the strength of the three-dimensionally movable unit 4,
the deterioration of the machining accuracy of the
three-dimensionally movable unit due to thermal expansion, and the
generation of seizure defects on the surface of rolls in the
three-dimensionally movable unit.
[0070] FIG. 5 is a diagram schematically illustrating an example of
the structure of each of the heating and cooling unit provided in
the three-dimensionally bending machine according to the present
invention. The ring-shaped high-frequency induction heating coil 5
is provided around the outer circumference of workpiece to be
heated, and heats a portion of workpiece at a temperature which is
high enough to enable the heated portion to be locally plastically
deformed. Then, a bending moment is applied to the heated portion
by action of the three-dimensionally movable unit, and subsequently
the cooling device 6 injects the cooling fluid to quench the heated
portion of the workpiece. Before high frequency induction heating,
the workpiece is held by the two pairs of supporting rolls. In this
example embodiment, the heating and cooling units are integrated
into one-piece, but the present invention is not limited
thereto.
[0071] According to this bending method, it is possible to
successively and continuously heat metal material as workpiece at a
temperature which allows coarse grains not to be generated and is
an A.sub.3 transformation point or more. In addition, the locally
heated portion of metal material is plastically deformed by the
three-dimensionally movable unit, and then immediately the cooling
fluid is injected to the deformed portion, which makes it possible
to ensure a cooling rate of 100.degree. C./sec or more.
[0072] Thus, the metal material as the workpiece subjected to
bending can have excellent shape fixability and stable quality. For
example, even when a workpiece having low strength is bent as a
starting material, it is possible to increase the strength of the
metal material by uniform quenching, and thus obtain a metal
product having a tensile strength of 900 MPa or more, preferably,
1300 MPa or more.
[0073] When the workpiece is thick in wall thickness, there are
some cases that it becomes difficult to ensure a cooling rate of
100.degree. C./sec or more. In this regard, when the workpiece is a
round tube, a rectangular tube, or a trapezoidal tube with a closed
cross section (metal tube), a mandrel as a cooling means can be
inserted into the workpiece having the closed cross section.
[0074] FIG. 6 is a diagram illustrating the structure of the
mandrel that is inserted into the workpiece having the closed cross
section (metal tube) in order to ensure the cooling rate of the
heavy-wall workpiece. When the workpiece with the closed cross
section is thick in wall thickness, a mandrel 6a can be inserted
into the workpiece as a cooling means. It is possible to ensure the
cooling rate by supplying a cooling medium into the mandrel 6a in
synchronization with the cooling device 6 provided around the outer
circumference of workpiece 1. In this case, a fluid or mist may be
supplied into the workpiece 1 to cool down the workpiece 1, and the
mandrel 6a is desirably made of a non-magnetic material or a
refractory material.
[0075] In the three-dimensionally bending machine according to the
present invention, the cooling medium supplied from the cooling
device 6 desirably includes water as a primary component and a
rust-preventative agent. When a sliding contact section of the
three-dimensionally bending machine is wet by cooling water
containing no rust-preventative agent, rust occurs, which may cause
serious machine malfunctions. Therefore, it is effective that the
rust-preventative agent be contained in the cooling water in order
to protect the machine.
[0076] Further, it is desirable that the cooling medium supplied
from the cooling unit contains water as a primary component, and a
quenching agent. For example, a quenching agent mixed with an
organic polymer agent has been known. When the quenching agent
having a predetermined concentration is mixed with water, it is
possible to adjust the cooling rate and thus ensure a stable
quenching performance.
[0077] 3. Structure of Three-Dimensionally Movable Unit
[0078] FIG. 7(a) is a diagram illustrating the structural examples
of shifting mechanisms in the three-dimensionally movable unit for
moving itself in a vertical and horizontal directions and a
rotating mechanism for rotating the same in a circumferential
direction, which is employed in the three-dimensionally bending
machine according to the present invention. The workpiece (round
tube) 1, which is a metal material such as an alloy, is supported
by the three-dimensionally movable unit 4 having four rolls. The
shifting mechanism for moving the three-dimensionally movable unit
in a vertical direction is operated by a driving motor 8, and the
shifting mechanism for moving the same in a horizontal direction is
operated by a driving motor 9. The rotating mechanism for rotating
the three-dimensionally movable unit in a circumferential direction
is operated by a driving motor 10. Further, the three-dimensionally
movable unit 4 includes a tilting mechanism for inclining itself in
both horizontal and vertical planes.
[0079] FIG. 7(b) shows an outline structure of the tilting
mechanism for inclining the three-dimensionally movable unit 4 in
both horizontal and vertical planes. The tilting mechanism to be
used in the present invention is not limited to a specific
structure, but any tilt mechanism in common use may be used. For
example, the tilting mechanism for the horizontal inclining may be
operated by a driving motor 21, and the tilting mechanism for the
vertical inclining may be operated by a driving motor 22.
[0080] FIG. 8 is a diagram illustrating the operation of a moving
mechanism for moving the three-dimensionally movable unit provided
in the three-dimensionally bending machine according to the present
invention in the forward or backward direction. As shown in FIG. 8,
when the length of an arm (processed length of the workpiece) is L,
a bending moment M required for bending is represented by
Expression A given below:
M=P.times.L=P.times.Rsin .theta.. [Expression A]
[0081] Therefore, as the length L of the arm increases, force P
exerted on pinch rolls (rolls as roller-dies in the
three-dimensionally movable unit) 4 becomes smaller. That is, in
view of the processing range from a small bending radius to a large
bending radius, when the three-dimensionally movable unit 4 cannot
be moved in the forward or backward direction, the force P,
required to process the workpiece 1 so as to have a small bending
radius, restricts the bending equipment. Therefore, when the length
L of the arm is set to be large so as to process the workpiece 1 to
have a small bending radius, the shifting mechanisms and the
tilting mechanism of the three-dimensionally movable unit require a
large stroke for processing workpiece to have a large bending
radius, which results in an increase in the scale of the
three-dimensionally bending machine.
[0082] Meanwhile, considering an instantaneous stopping accuracy or
allowable play (movement runout) of the three-dimensionally bending
machine, when the length L of the arm is small, the processing
accuracy is lowered. Therefore, it is possible to select the
optimum length L of the arm by moving the three-dimensionally
movable unit 4 in the forward or backward direction according to
the bending radius of the workpiece 1, and thus to widen the
available processing range. In this case, it is also possible to
ensure sufficient processing accuracy without increasing the scale
of the three-dimensionally bending machine.
[0083] Furthermore, in the three-dimensionally bending machine
according to the present invention, the high-frequency induction
heating and cooling unit can have, independently or integrally, a
moving mechanism for moving itself in the forward or backward
direction. This structure makes it possible to ensure synchronizing
with the three-dimensionally movable unit and to heat the leading
end of workpiece at the beginning of bending. As a result, it is
possible to improve workability and operability when the metal tube
is mounted or demounted.
[0084] FIGS. 9(a) to 9(c) are diagrams illustrating examples of the
configuration of the three-dimensionally movable unit provided in
the three-dimensionally bending machine of the present invention.
Specifically, FIG. 9(a) shows a three-dimensionally movable unit
including two rolls as roller-dies when a workpiece is a member
with a closed cross section such as a round tube, FIG. 9(b) shows a
three-dimensionally movable unit including two rolls when a
workpiece is a member with a closed cross section such as a
rectangular tube, such as a channel, and FIG. 9(c) shows a
three-dimensionally movable unit including four rolls when a
workpiece is a member with a closed cross section such as a
rectangular tube or a member with an irregular cross section, such
as a channel.
[0085] The roll caliber type of the three-dimensionally movable
unit 4 can be designed according to the cross section of the
workpiece 1. The number of rolls is not limited to 2 or 4, as shown
in FIGS. 9(a) to 9(c), but the three-dimensionally movable unit may
include three rolls. In general, the workpiece is made by the metal
material used for bending can have a closed cross section with a
circular shape, a rectangular shape, a trapezoidal shape, or a
complex shape, an open cross section formed by a roll forming
operation, or an irregular cross section formed by an extrusion
operation. However, when the workpiece 1 has a substantially
rectangular cross section, as shown in FIG. 9(c), it is desirable
that the three-dimensionally movable unit includes four rolls.
[0086] In the three-dimensionally bending machine according to the
present invention, as shown in FIG. 7, a rotating mechanism for
rotating in a circumferential direction can be provided in the
three-dimensionally movable unit 4 in order to twist the workpiece
At the same time, although not shown in FIG. 1, the feeding unit 3
can be provided with a chucking mechanism 7 capable of holding and
rotating the workpiece 1 in a circumferential direction, which
serves as a rotating mechanism.
[0087] Therefore, in order to twist the workpiece in the
three-dimensionally bending machine according to the present
invention, the following methods can be used: a method of twisting
the leading end of the workpiece using the rotating mechanism of
the three-dimensionally movable unit; and a method for twisting the
rear end of the workpiece using the rotating mechanism of the
feeding unit. In general, when the method of twisting the rear end
of the workpiece using the rotating mechanism of the feeding unit
is employed, a compact machine structure is obtained. On the other
hand, in the method of twisting the leading end of the workpiece
using the rotating mechanism of the three-dimensionally movable
unit, as shown in FIG. 7, there is an issue that the scale of the
three-dimensionally bending machine will become large. However,
both the methods can be used to twist the workpiece.
[0088] In the three-dimensionally bending machine according to the
present invention, a rotating mechanism for rotating in a
circumferential direction may be provided in the supporting unit
(the supporting rolls or the supporting guide), which makes it
possible to rotate workpiece in a circumferential direction in
synchronization with the rotation of the feeding unit. Either the
method of twisting the leading end of the workpiece using the
rotating mechanism of the three-dimensionally movable unit or the
method of twisting the rear end of workpiece using the rotating
mechanism of the feeding unit can be used to accurately twist the
workpiece in synchronization with the supporting unit.
[0089] In the three-dimensionally bending machine according to the
present invention, a rolls driving and rotating mechanism may be
provided in the three-dimensionally movable unit. In this case, the
roll can be driven to revolve by, for example, a driving motor
according to the feed amount of the workpiece fed by the feeding
unit. That is, when a compressive stress exerted on a bent portion
is reduced and the revolving speed of the rolls of the
three-dimensionally movable unit is controlled so as to be
synchronized with the feed amount of the workpiece fed by the
feeding unit, it is possible to apply tensile stress to the bent
portion, and the available bending range can be widened. In
addition, it is possible to improve the bending accuracy of the
metal product.
[0090] 4. Preheating Unit and Operation Thereof
[0091] The three-dimensionally bending machine according to the
present invention includes a preheating unit at the upstream side
of the heating unit. The preheating unit can perform preferential
heating or otherwise, two- or more-stage heating, i.e.,
plural-stage heating on workpiece. When the preheating unit
performs plural-stage heating, it is possible to disperse heating
load on the workpiece, and thus improve bending efficiency.
[0092] FIG. 10 is a diagram illustrating the operation of the
preheating unit that performs preferential heating on the
workpiece. When the high-frequency induction preheating coil 5a is
used as the preheating unit to perform preferential heating on the
workpiece 1, the workpiece 1 is disposed while being off-set
relative to the centerline axis of the high-frequency induction
preheating coil 5a in consideration of an orientation to which the
workpiece is bent by the three-dimensionally movable unit. Thus,
the heating temperature of the portion of the workpiece 1 intended
to be the inner radius side of the bend can be controlled to be
lower than that of the outer radius side of the bend.
[0093] Specifically, in FIG. 10, the workpiece 1 is disposed such
that a portion A is close to the high-frequency induction
preheating coil 5a, so that the temperature of the outer surface of
portion A corresponding to the outer radius side of the bent
portion is higher than the temperature of the outer surface of
portion B corresponding to the inner radius side of the bent
portion. Such configuration of the heated portion of the workpiece
1 can effectively prevent the wrinkles on the inner radius side of
the bent portion and cracking on the outer radius side of the bent
portion from being generated.
[0094] In the three-dimensionally bending machine according to the
present invention, a lubricant can be supplied to the
three-dimensionally movable unit. Therefore, even when scales
generated from the heated portion of the workpiece are got into
rolls in the three-dimensionally movable unit, the lubricant can
retard the generation of seizure defects on the surface
thereof.
[0095] Similarly, in the three-dimensionally bending machine
according to the present invention, a cooling fluid can be supplied
to the three-dimensionally movable unit. A cooling device for the
movable unit is provided in the three-dimensionally movable unit in
the vicinity of a position where the workpiece is clamped, and the
cooling fluid is supplied to the three-dimensionally movable unit
through the cooling device. In this way, the three-dimensionally
movable unit is cooled down by the cooling fluid. As a result, it
is possible to prevent the decrease of the strength of the
three-dimensionally movable unit, the lowering of bending accuracy
due to thermal expansion of the three-dimensionally movable unit,
and seizure defects on the surface of rolls in the
three-dimensionally movable unit.
[0096] 5. Structure and Arrangement of Articulated Robot
[0097] FIG. 11 is a diagram illustrating the overall structure and
arrangement of an articulated robot that is applicable to the
three-dimensionally bending machine according to the present
invention. As shown in FIG. 11, an articulated robot 11 for the
three-dimensionally movable unit 4 can be provided at the
downstream side of the three-dimensionally bending machine.
[0098] The articulated robot 11 for the three-dimensionally movable
unit includes a fixed surface 12 that is fixed to an operating
surface, three arms 13, 14, and 15, and three joints 16, 17, and 18
that connect the arms 13, 14, and 15, respectively, and each of
these can rotate about its axis. The three-dimensionally movable
unit 4 is attached to the leading arm 15 of the articulated robot
11.
[0099] FIG. 12 is a diagram illustrating another example of the
structure of the articulated robot that is applicable to the
three-dimensionally bending machine according to the present
invention. In the three-dimensionally bending machine shown in FIG.
11, only the articulated robot for the three-dimensionally movable
unit is provided. However, both an articulated robot 11 for use in
a heating and cooling unit, and the one for use in the
three-dimensionally movable unit can be concurrently provided. The
use of the two articulated robots makes it possible to further
improve bending efficiency.
[0100] In the three-dimensionally bending machine according to the
present invention, at least one articulated robot having three
joints each of which can rotate about its axis is provided, so
that, during bending workpiece, the articulated robots can perform,
on the basis of control signals, a series of operations such as
forward and backward movement, swirling or rotational motion, and
concurrent motion, effected by the shifting mechanism, the tilting
mechanism, and the moving mechanism of the three-dimensionally
movable unit 4. That is, during the bending of the workpiece, the
articulated robots can perform a total of six types of operations
effected by manipulators, on the basis of the control signals. As a
result, it is possible to improve bending efficiency and reduce the
scale of a three-dimensionally bending machine.
[0101] 6. Bending-Equipment Line
[0102] As described above, a workpiece with a closed cross section
having a circular shape or the like or an open cross section is
used for the three-dimensionally bending machine according to the
present invention. An electric resistance welded steel tube has
been generally used as materials with a circular closed cross
section, round tubes, and a steel material made by roll forming has
been generally used as materials with the open cross section.
[0103] FIG. 13 is a diagram illustrating the overall structure of
an electric resistance welded steel tube production line that is
used to produce a workpiece. An electric resistance welded steel
tube production line 19 is used to produce steel tubes from a
strip-shaped steel sheet 20. The electric resistance welded steel
tube production line 19 includes an uncoiler 21 for continuously
unrolling into the strip-shaped steel sheet 20 from a strip-shaped
steel sheet coil roll, a forming means 22 having a plurality of
roll forming devices that form the unrolled strip-shaped steel
sheet 20 into tubular product having a predetermined
cross-sectional shape, a welding means 23 having a welding machine
that welds the opposite side edges of the strip-shaped steel sheet
to form continuous steel tubular product, a weld bead cutter, a
post-annealing apparatus, a post-processing apparatus 24 that
adjusts the size of the continuous product to a predetermined
dimension, and a cutting apparatus 25 having a flying cutter for
cutting the product of the predetermined dimension to a specific
length, which are sequentially arranged in the order as above.
[0104] FIG. 14 is a diagram illustrating the overall structure of a
roll forming line used to produce a workpiece. A roll forming line
26 is used to form the strip-shaped steel sheet 20 into a
predetermined shape. The roll forming line 26 includes the uncoiler
21 that the strip-shaped steel sheet 20 as a blank is unwound and
unrolled from the coil, a forming apparatus 27 having roll forming
devices that form the strip-shaped steel sheet 20 unrolled by the
uncoiler 21 into a continuous shape blank of a predetermined shape,
and a cutting apparatus 28 having a flying cutter that continuously
cuts the formed blank of a predetermined shape made by roll forming
from the strip-shaped steel sheet 20 to a specific length.
[0105] A workpiece produced by the electric resistance welded steel
tube production line 19 shown in FIG. 13 or the roll forming line
26 shown in FIG. 14 is supplied to a bending machine as a metal
material to be bent. When the production lines and the bending
machine are separated from each other, it is necessary to ensure a
place for stocking workpiece since the processing speeds between
the production line and the bending machine are different from each
other. In addition, an auxiliary transfer equipment and means for
transporting workpieces between the production line and the bending
machine, such as a crane and a truck, are needed.
[0106] The three-dimensionally bending machine according to the
present invention is sequentially provided at the exit side of the
electric resistance welded steel tube production line 19 or the
roll forming line 26. Therefore, an overall equipment line from
that for supplying workpieces through the bending machine becomes
compact, while allowing their operation conditions to be properly
adjusted, whereby it becomes possible to effectively perform a
bending operation to produce accurate and inexpensive bent
products.
INDUSTRIAL APPLICABILITY
[0107] According to a bending machine, and a bending-equipment line
according to the present invention, even when there is a need for
bending a workpiece in various shapes, such as the case that the
workpiece is three-dimensionally bent in different directions in a
three-dimensional continuous bending operation, and even when there
is a need for bending a workpiece having high strength, the
workpiece is uniformly cooled down. Therefore, it is possible to
effectively obtain the product having excellent shape fixability
despite having high strength, and uniform hardness distribution at
a low cost.
[0108] Further, since the three-dimensionally movable unit clamps
workpiece, it is possible to retard the generation of seizure
defects on the surface of the three-dimensionally movable unit.
Therefore, the accuracy of a bending operation can be ensured, and
a bending operation can be performed with a high degree of
operation efficiency.
* * * * *