U.S. patent application number 15/578657 was filed with the patent office on 2018-04-19 for method for manufacturing joined member and apparatus for manufacturing the same.
The applicant listed for this patent is ORIGIN ELECTRIC COMPANY, LIMITED. Invention is credited to Yasuo KADOYA, Yuki OSHINO.
Application Number | 20180104762 15/578657 |
Document ID | / |
Family ID | 55793257 |
Filed Date | 2018-04-19 |
United States Patent
Application |
20180104762 |
Kind Code |
A1 |
KADOYA; Yasuo ; et
al. |
April 19, 2018 |
METHOD FOR MANUFACTURING JOINED MEMBER AND APPARATUS FOR
MANUFACTURING THE SAME
Abstract
To provide a method and apparatus for manufacturing a joined
member that inhibit occurrence of cracks in a joined member even
when the joined portion is quenched when members are welded
together. The method includes placing the first member D and the
second member E with a joint target portion Df and a joint target
portion Ef being in contact with each other, welding the joint
target portions by heating, subjecting the first member D after the
welding to a process for inhibiting occurrence of cracks, and
tempering a portion where the first and second members have been
welded to each other by electromagnetic heating. The apparatus
includes a first electrode 11 to contact with the first member D; a
second electrode 12 to contact with the second member E; and an
induction heating coil 23 for performing induction heating of a
portion where a joint target portions Df and Ef have been contacted
and joined to each other, and the induction heating coil 23 is
placed between the two electrodes 11 and 12 when the induction
heating is performed.
Inventors: |
KADOYA; Yasuo; (Saitama,
JP) ; OSHINO; Yuki; (Saitama, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
ORIGIN ELECTRIC COMPANY, LIMITED |
Saitama |
|
JP |
|
|
Family ID: |
55793257 |
Appl. No.: |
15/578657 |
Filed: |
June 2, 2016 |
PCT Filed: |
June 2, 2016 |
PCT NO: |
PCT/JP2016/066485 |
371 Date: |
November 30, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C21D 9/50 20130101; B23K
11/241 20130101; C21D 1/42 20130101; Y02P 10/25 20151101; B23K
2103/04 20180801; B23K 11/16 20130101; B23K 11/36 20130101; Y02P
10/253 20151101; B23K 31/00 20130101; B23K 11/02 20130101; B23K
2103/06 20180801 |
International
Class: |
B23K 11/16 20060101
B23K011/16; B23K 11/02 20060101 B23K011/02; B23K 11/36 20060101
B23K011/36; B23K 11/24 20060101 B23K011/24; C21D 1/42 20060101
C21D001/42; C21D 9/50 20060101 C21D009/50 |
Claims
1. A method for manufacturing a joined member by joining a first
member formed of a metal material having a possibility of
undergoing quenching and a second member formed of a metal
material, the method comprising: a contact-placing step of placing
the first member and the second member with a joint target portion
of the first member and a joint target portion of the second member
being in contact with each other; a welding step of welding the
joint target portions of the first member and the second member by
heating; a crack-inhibition step of subjecting the first member
after the welding step to a process for inhibiting occurrence of
cracks; an electromagnetic heating step of tempering a portion
where the first member and the second member have been welded to
each other by electromagnetic heating; wherein the welding step is
a step of performing resistance welding of the joint target
portions of the first member and the second member with
simultaneous application of pressure; and wherein the
crack-inhibition step includes heating the portion where the first
member and the second member have been welded to each other, by
passing an electric current therethrough in order to achieve
preliminary tempering.
2. The method for manufacturing a joined member according to claim
1, wherein the electromagnetic heating step is achieved by
induction heating using an induction heating coil, and the
electromagnetic heating step includes: placing the induction
heating coil in a vicinity of a first edge forming an outer
circumference of a joint surface between the first member and the
second member; and tempering the joint surface on a side of an
opposite edge opposed to the first edge first and then tempering
the joint surface on a side of the first edge with an output from
the induction heating coil reduced to a level lower than that used
to temper the joint surface on the side of the opposite edge.
3. The method for manufacturing a joined member according to claim
1, wherein the electromagnetic heating step is achieved by
induction heating using induction heating coils, and the
electromagnetic heating step includes: placing one of the induction
heating coils in a vicinity of a first edge forming an outer
circumference of the joint surface between the first member and the
second member and the other in a vicinity of an opposite edge
opposed to the first edge of the joint surface, and tempering the
joint surface on the side of the first edge with the induction
heating coil placed in the vicinity of the first edge and tempering
the joint surface on the side of the opposite edge with the
induction heating coil placed in the vicinity of the opposite
edge.
4. A method for manufacturing a joined member by joining a first
member formed of a metal material having a possibility of
undergoing quenching and a second member formed of a metal
material, the method comprising: a contact-placing step of placing
the first member and the second member with a joint target portion
of the first member and a joint target portion of the second member
being in contact with each other; a welding step of welding the
joint target portions of the first member and the second member by
heating; a crack-inhibition step of subjecting the first member
after the welding step to a process for inhibiting occurrence of
cracks; and an electromagnetic heating step of tempering a portion
where the first member and the second member have been welded to
each other by electromagnetic heating; wherein the electromagnetic
heating step is achieved by induction heating using an induction
heating coil, and the electromagnetic heating step includes:
placing the induction heating coil in a vicinity of a first edge
forming an outer circumference of a joint surface between the first
member and the second member; and tempering the joint surface on a
side of an opposite edge opposed to the first edge first and then
tempering the joint surface on the side of the first edge with an
output from the induction heating coil reduced to a level lower
than that used to temper the joint surface on the side of the
opposite edge.
5. A method for manufacturing a joined member by joining a first
member formed of a metal material having a possibility of
undergoing quenching and a second member formed of a metal
material, the method comprising: a contact-placing step of placing
the first member and the second member with a joint target portion
of the first member and a joint target portion of the second member
being in contact with each other; a welding step of welding the
joint target portions of the first member and the second member by
heating; a crack-inhibition step of subjecting the first member
after the welding step to a process for inhibiting occurrence of
cracks; and an electromagnetic heating step of tempering a portion
where the first member and the second member have been welded to
each other by electromagnetic heating; wherein the electromagnetic
heating step is achieved by induction heating using induction
heating coils, and the electromagnetic heating step includes:
placing one of the induction heating coils in a vicinity of a first
edge forming an outer circumference of the joint surface between
the first member and the second member and the other in a vicinity
of an opposite edge opposed to the first edge of the joint surface,
and tempering the joint surface on the side of the first edge with
the induction heating coil placed in the vicinity of the first edge
and tempering the joint surface on the side of the opposite edge
with the induction heating coil placed in the vicinity of the
opposite edge.
6. The method for manufacturing a joined member according to claim
4, wherein the welding step is a step of performing resistance
welding of the joint target portions of the first member and the
second member with simultaneous application of pressure; and
wherein the crack-inhibition step includes maintaining the
application of pressure in the welding step.
7. A joined member manufacturing apparatus for manufacturing a
joined member, the joined member being manufactured by joining a
first member and a second member, the first member being made of a
metal material having a possibility of undergoing quenching, the
second member being made of a metal material, the joined member
manufacturing apparatus comprising: a first electrode to be brought
into contact with the first member; a second electrode to be
brought into contact with the second member; an induction heating
coil for performing induction heating of a portion where a joint
target portion of the first member in contact with the first
electrode and a joint target portion of the second member in
contact with the second electrode have been contacted and joined to
each other; and a controller for controlling supply of electric
current to the first electrode and the second electrode and supply
of electric current to the induction heating coil; wherein the
induction heating coil is configured to be placed between the first
electrode and the second electrode when the induction heating of a
portion where the first member and the second member have been
joined to each other is performed; and wherein the controller is
configured to pass an electric current between the first electrode
brought in contact with the first member and the second electrode
brought in contact with the second member, with simultaneous
application of pressure to the joint target portion of the first
member and the joint target portion of the second member, the joint
target portions being in contact with each other, to weld the joint
target portions, to temper a joint surface on a side of an opposite
edge opposed to a first edge forming an outer circumference of the
joint surface between the first member and the second member, with
the induction heating coil being placed in a vicinity of the first
edge, while maintaining the application of pressure to the joint
surface, and then to temper the joint surface on a side of the
first edge with an output from the induction heating coil reduced
to a level lower than that used to temper the joint surface on the
side of the opposite edge.
8. The joined member manufacturing apparatus according to claim 7,
wherein the controller is configured to temper the joint surface on
the side of the first edge forming an outer circumference of the
joint surface, with an induction heating coil placed in a vicinity
of the first edge, and to temper the joint surface on the side of
the opposite edge opposed to the first edge, with an induction
heating coil placed in a vicinity of the opposite edge, instead of
being configured to temper the joint surface on the side of an
opposite edge opposed to the first edge forming an outer
circumference of the joint surface, with the induction heating coil
being placed in the vicinity of the first edge, and then to temper
the joint surface on the side of the first edge with an output from
the induction heating coil reduced to a level lower than that used
to temper the joint surface on the side of the opposite edge.
9. A joined member manufacturing apparatus for manufacturing a
joined member, the joined member being manufactured by joining a
first member and a second member, the first member being made of a
metal material having a possibility of undergoing quenching and
formed to have a ring-like shape, the second member being made of a
metal material and formed to have a circular cylindrical shape, the
joined member manufacturing apparatus comprising: a first electrode
to be brought into contact with the first member; a second
electrode to be brought into contact with the second member; and
induction heating coils for performing induction heating of a
portion where a joint target portion of the first member in contact
with the first electrode and a joint target portion of the second
member in contact with the second electrode are contacted and
joined to each other; wherein the induction heating coils comprise
a first induction heating coil wound into a circle with a diameter
slightly larger than an outer diameter of the second member and a
second induction heating coil wound into a circle with a diameter
smaller than that of the first induction heating coil and placed
below the first induction heating coil, the first induction heating
coil and the second induction heating coil being configured to be
placed between the first electrode and the second electrode when
induction heating is performed on a portion where the first member
and the second member are joined to each other.
10. A method for manufacturing the joined member with the joined
member manufacturing apparatus according to claim 7, the method
comprising: a member placing step of placing the first member and
the second member in the joined member manufacturing apparatus; an
electrode energizing step of passing an electric current between
the first electrode and the second electrode; and a coil energizing
step of passing an electric current through the induction heating
coil.
11. The method for manufacturing a joined member according to claim
5, wherein the welding step is a step of performing resistance
welding of the joint target portions of the first member and the
second member with simultaneous application of pressure; and
wherein the crack-inhibition step includes maintaining the
application of pressure in the welding step.
12. A method for manufacturing the joined member with the joined
member manufacturing apparatus according to claim 9, the method
comprising: a member placing step of placing the first member and
the second member in the joined member manufacturing apparatus; an
electrode energizing step of passing an electric current between
the first electrode and the second electrode; and a coil energizing
step of passing an electric current through the induction heating
coil.
Description
TECHNICAL FIELD
[0001] The present invention relates to a method for manufacturing
a joined member and a joined member manufacturing apparatus, more
particularly, to a method for manufacturing a joined member and a
joined member manufacturing apparatus in which occurrence of cracks
in a welded portion of the joined member is inhibited.
BACKGROUND ART
[0002] When two members are welded to each other, mash seam welding
where a pair of roller electrodes is moved along overlap margins of
portions to be welded under application of pressure and electric
current can be employed. One problem of mash seam welding is its
prolonged welding time. As a welding method that solves the problem
of mash seam welding, there is a method in which portions of two
objects to be welded are slightly overlapped and a welding electric
current is applied with a pressure being applied between the
portions to be welded (refer to Patent Document 1, for
example).
PRIOR ART DOCUMENT
Patent Document
[0003] Patent Document 1: JP 2004-17048 A
SUMMARY OF THE INVENTION
Problem to be Solved by the Invention
[0004] In a welding technique by heating, when objects to be welded
are made of high-carbon steel such as quenched carburized steel,
the welded portions of the objects may be changed to a hard and
brittle quenched structure and suffer from cracks.
[0005] The present invention has been made in view of the above
problem, and it is, therefore, an object of the present invention
to provide a method and apparatus for manufacturing a joined member
that inhibit occurrence of cracks in the manufactured joined member
even when the joined portion is quenched when two members are
welded together.
Means for Solving the Problem
[0006] To achieve the above object, a method for manufacturing a
joined member according to the first aspect of the present
invention is, as shown in FIGS. 3A, 3C and 3D, for example, a
method for manufacturing a joined member C (see FIG. 2C, for
example) by joining a first member D formed of a metal material
having a possibility of undergoing quenching and a second member E
formed of a metal material, and the method includes a
contact-placing step of placing the first member D and the second
member E with a joint target portion Df of the first member D and a
joint target portion Ef of the second member E being in contact
with each other (see FIG. 3A); a welding step of welding the joint
target portions of the first member D and the second member E by
heating (see FIG. 3C); a crack-inhibition step of subjecting the
first member D after the welding step to a process for inhibiting
occurrence of cracks; an electromagnetic heating step of tempering
a portion where the first member D and the second member E have
been welded to each other by electromagnetic heating (see FIG. 3D);
wherein the welding step is a step of performing resistance welding
of the joint target portions of the first member D and the second
member E with simultaneous application of pressure; and wherein the
crack-inhibition step includes heating the portion where the first
member D and the second member E have been welded to each other, by
passing an electric current therethrough in order to achieve
preliminary tempering.
[0007] With this configuration, because the welding and
electromagnetic heating can be performed at different locations,
the degree of freedom of steps can be increased.
[0008] As for the method for manufacturing a joined member
according to the second aspect of the present invention, as shown
in FIGS. 3D, 4A and 4B, for example, in the method for
manufacturing a joined member according to the first aspect,
electromagnetic heating step (see FIG. 3D) is achieved by induction
heating using an induction heating coil 23, and the electromagnetic
heating step includes: placing the induction heating coil 23 in a
vicinity of a first edge Sn forming an outer circumference of a
joint surface between the first member D and the second member E;
and tempering the joint surface Jf on a side of an opposite edge Sf
opposed to the first edge Sn first and then tempering the joint
surface Jn on a side of the first edge Sn with an output from the
induction heating coil 23 reduced to a level lower than that used
to temper the joint surface Jf on the side of the opposite edge
Sf.
[0009] With this configuration, the entire joint surface can be
tempered with a single installation of an induction heating
coil.
[0010] As for the method for manufacturing a joined member
according to the third aspect of the present invention, as shown in
FIG. 5, for example, in the method for manufacturing a joined
member according to the first aspect, the electromagnetic heating
step is achieved by induction heating using induction heating coils
23 and 23A, and the electromagnetic heating step includes: placing
one 23 of the induction heating coils in a vicinity of a first edge
Sn forming an outer circumference of the joint surface between the
first member D and the second member E and the other 23A in a
vicinity of an opposite edge Sf opposed to the first edge Sn of the
joint surface, and tempering the joint surface Jn on the side of
the first edge Sn with the induction heating coil 23 placed in the
vicinity of the first edge Sn and tempering the joint surface Jf on
the side of the opposite edge Sf with the induction heating coil
23A placed in the vicinity of the opposite edge Sf.
[0011] With this configuration, because the first edge side and the
opposite edge side of the joint surface can be tempered
simultaneously, the time required for the electromagnetic heating
step can be shortened.
[0012] To achieve the above object, a method for manufacturing a
joined member according to the fourth aspect of the present
invention is, as shown in FIGS. 3A, 3C, 3D, 4A and 4B, for example,
a method for manufacturing a joined member C (see FIG. 2C, for
example) by joining a first member D formed of a metal material
having a possibility of undergoing quenching and a second member E
formed of a metal material, and the method includes a
contact-placing step of placing the first member D and the second
member E with a joint target portion Df of the first member D and a
joint target portion Ef of the second member E being in contact
with each other (see FIG. 3A); a welding step of welding the joint
target portions of the first member D and the second member E by
heating (see FIG. 3C); a crack-inhibition step of subjecting the
first member D after the welding step to a process for inhibiting
occurrence of cracks; and an electromagnetic heating step of
tempering a portion where the first member D and the second member
E have been welded to each other by electromagnetic heating (see
FIG. 3D); wherein the electromagnetic heating step is achieved by
induction heating using an induction heating coil 23, and the
electromagnetic heating step includes: placing the induction
heating coil 23 in a vicinity of a first edge Sn forming an outer
circumference of a joint surface between the first member D and the
second member E; and tempering the joint surface Jf on a side of an
opposite edge Sf opposed to the first edge Sn first and then
tempering the joint surface Jn on the side of the first edge Sn
with an output from the induction heating coil 23 reduced to a
level lower than that used to temper the joint surface Jf on the
side of the opposite edge Sf.
[0013] With this configuration, the entire joint surface can be
tempered with a single installation of an induction heating
coil.
[0014] To achieve the above object, a method for manufacturing a
joined member according to the fifth aspect of the present
invention is, as shown in FIGS. 3A, 3C, 3D and 5, for example, a
method for manufacturing a joined member C (see FIG. 2C, for
example) by joining a first member D formed of a metal material
having a possibility of undergoing quenching and a second member E
formed of a metal material, and the method includes a
contact-placing step of placing the first member D and the second
member E with a joint target portion Df of the first member D and a
joint target portion Ef of the second member E being in contact
with each other (see FIG. 3A); a welding step of welding the joint
target portions of the first member D and the second member E by
heating (see FIG. 3C); a crack-inhibition step of subjecting the
first member D after the welding step to a process for inhibiting
occurrence of cracks; and an electromagnetic heating step of
tempering a portion where the first member D and the second member
E have been welded to each other by electromagnetic heating (see
FIG. 3D); wherein the electromagnetic heating step is achieved by
induction heating using induction heating coils 23 and 23A, and the
electromagnetic heating step includes: placing one 23 of the
induction heating coils in a vicinity of a first edge Sn forming an
outer circumference of the joint surface between the first member D
and the second member E and the other 23A in a vicinity of an
opposite edge Sf opposed to the first edge Sn of the joint surface,
and tempering the joint surface Jn on the side of the first edge Sn
with the induction heating coil 23 placed in the vicinity of the
first edge Sn and tempering the joint surface Jf on the side of the
opposite edge Sf with the induction heating coil 23A placed in the
vicinity of the opposite edge Sf.
[0015] With this configuration, because the first edge side and the
opposite edge side of the joint surface can be tempered
simultaneously, the time required for the electromagnetic heating
step can be shortened.
[0016] As for the method for manufacturing a joined member
according to the sixth aspect of the present invention, as shown in
FIGS. 3A to 3E, for example, in the method for manufacturing a
joined member according to the fourth or fifth aspect, the welding
step is a step of performing resistance welding of the joint target
portions of the first member D and the second member E with
simultaneous application of pressure; and the crack-inhibition step
includes maintaining the application of pressure in the welding
step.
[0017] With this configuration, because the welding and
electromagnetic heating can be performed sequentially, productivity
can be improved.
[0018] To achieve the above object, a joined member manufacturing
apparatus according to the seventh aspect of the present invention
is, as shown in FIG. 1, for example, an apparatus for manufacturing
a joined member C (see FIG. 2C, for example) by joining a first
member D formed of a metal material having a possibility of
undergoing quenching and a second member E formed of a metal
material, and the joined member manufacturing apparatus includes a
first electrode 11 to be brought into contact with the first member
D; a second electrode 12 to be brought into contact with the second
member E; an induction heating coil 23 for performing induction
heating of a portion where a joint target portion Df (see FIG. 2B,
for example) of the first member D in contact with the first
electrode 11 and a joint target portion Ef (see FIG. 2B, for
example) of the second member E in contact with the second
electrode 12 have been contacted and joined to each other; and a
controller 50 for controlling supply of electric current to the
first electrode 11 and the second electrode 12 and supply of
electric current to the induction heating coil 23; wherein the
induction heating coil 23 is configured to be placed between the
first electrode 11 and the second electrode 12 when the induction
heating of a portion where the first member D and the second member
E have been joined to each other is performed; and wherein the
controller 50 is configured to pass an electric current between the
first electrode 11 brought in contact with the first member D and
the second electrode 12 brought in contact with the second member
E, with simultaneous application of pressure to the joint target
portion Df (see FIG. 2B, for example) of the first member D and the
joint target portion Ef (see FIG. 2B, for example) of the second
member E, the joint target portions being in contact with each
other, to weld the joint target portions, to temper a joint surface
Jf (see FIG. 4A, for example) on a side of an opposite edge Sf (see
FIG. 4A, for example) opposed to a first edge Sn (see FIG. 4A, for
example) forming an outer circumference of the joint surface
between the first member D and the second member E, with the
induction heating coil 23 being placed in a vicinity of the first
edge Sn, while maintaining the application of pressure to the joint
surface, and then to temper the joint surface Jn (see FIG. 4A, for
example) on a side of the first edge Sn with an output from the
induction heating coil 23 reduced to a level lower than that used
to temper the joint surface Jf on the side of the opposite edge
Sf.
[0019] As for the joined member manufacturing apparatus according
to the eighth aspect of the present invention, as shown in FIGS. 1
and 5, for example, in the joined member manufacturing apparatus
according to the seventh aspect, the controller 50 is configured to
temper the joint surface Jn on the side of the first edge Sn
forming an outer circumference of the joint surface, with an
induction heating coil 23 placed in a vicinity of the first edge
Sn, and to temper the joint surface Jf on the side of the opposite
edge Sf opposed to the first edge Sn, with an induction heating
coil 23A placed in a vicinity of the opposite edge Sf, instead of
being configured to temper the joint surface Jf on the side of an
opposite edge Sf opposed to the first edge Sn forming an outer
circumference of the joint surface, with the induction heating coil
23 being placed in the vicinity of the first edge Sn, and then to
temper the joint surface Jn on the side of the first edge Sn with
an output from the induction heating coil 23 reduced to a level
lower than that used to temper the joint surface Jf on the side of
the opposite edge Sf.
[0020] To achieve the above object, a joined member manufacturing
apparatus according to the ninth aspect of the present invention
is, as shown in FIGS. 1 and 5, for example, an apparatus for
manufacturing a joined member C (see FIG. 2C, for example) by
joining a first member D made of a metal material having a
possibility of undergoing quenching and formed to have a ring-like
shape and a second member E made of a metal material and formed to
have a circular cylindrical shape, and the joined member
manufacturing apparatus includes a first electrode 11 to be brought
into contact with the first member D; a second electrode 12 to be
brought into contact with the second member E; and an induction
heating coils 23 and 23A for performing induction heating of a
portion where a joint target portion Df (see FIG. 2B, for example)
of the first member D in contact with the first electrode 11 and a
joint target portion Ef (see FIG. 2B, for example) of the second
member E in contact with the second electrode 12 are contacted and
joined to each other; wherein the induction heating coils include a
first induction heating coil 23 wound into a circle with a diameter
slightly larger than an outer diameter of the second member E and a
second induction heating coil 23A wound into a circle with a
diameter smaller than that of the first induction heating coil 23
and placed below the first induction heating coil 23, the first
induction heating coil 23 and the second induction heating coil 23A
being configured to be placed between the first electrode 11 and
the second electrode 12 when induction heating is performed on a
portion where the first member D and the second member E are joined
to each other.
[0021] As for a method for manufacturing a joined member according
to the tenth aspect of the present invention is, as shown in FIGS.
1, 3A, 3C and 3D, for example, a method for manufacturing a joined
member C (see FIG. 2C, for example) with the joined member
manufacturing apparatus 1 according to any one of the seventh
aspect to the ninth aspect, and the method includes a member
placing step of placing the first member D and the second member E
in the joined member manufacturing apparatus 1 (see FIG. 3A); an
electrode energizing step of passing an electric current between
the first electrode 11 and the second electrode 12 (see FIG. 3C);
and a coil energizing step of passing an electric current through
the induction heating coil 23 (see FIG. 3D).
[0022] With this configuration, even when the joined portion is
quenched when the joint target portions are joined using the first
electrode and the second electrode, the jointed portion can be
tempered by induction heating by the induction heating coil. Thus,
occurrence of cracks in the joined portion can be inhibited.
Effect of the Invention
[0023] According to the present invention, even when the joined
portion is quenched, the jointed portion can be tempered by
electromagnetic heating. Thus, occurrence of cracks in the joined
portion can be inhibited.
BRIEF DESCRIPTION OF DRAWINGS
[0024] FIG. 1 is a general configuration diagram of a joined member
manufacturing apparatus according to an embodiment of the present
invention.
[0025] FIG. 2A is a perspective view of a first member and a second
member, FIG. 2B is a cross-sectional view of the first member and
the second member, and FIG. 2C is a cross-sectional view of a
joined member.
[0026] FIGS. 3A, 3B, 3C, 3D and 3E are a schematic view,
illustrating the procedure of a method for manufacturing a joined
member according to an embodiment of the present invention.
[0027] FIG. 4A is a partial cross-sectional view, illustrating a
progress of tempering by high-frequency induction heating, and FIG.
4B is a partial cross-sectional perspective view, illustrating a
welding-completed portion.
[0028] FIG. 5 is a cross-sectional view, illustrating heating coils
and their vicinity in a joined member manufacturing apparatus
according to a modification of the embodiment of the present
invention.
DESCRIPTION OF EMBODIMENTS
[0029] This application is based on the Patent Application No.
2015-115808 filed on Jun. 8, 2015 in Japan, the contents of which
ire hereby incorporated in its entirety by reference into the
present application, as part thereof.
[0030] The present invention will become more fully understood from
the detailed description given hereinbelow. Further range of
application of the present invention will become clearer from the
detailed description given hereinbelow. However, the detailed
description and the specific embodiment are illustrated of desired
embodiments of the present invention and are described only for the
purpose of explanation. Various changes and modifications will be
apparent to those ordinary skilled in the art on the basis of the
detailed description.
[0031] The applicant has no intention to give to public any
disclosed embodiment. Among the disclosed changes and
modifications, those which may not literally fall within the scope
of the patent claims constitute, therefore, a part of the present
invention in the sense of doctrine of equivalents.
[0032] Description will hereinafter be made of an embodiment of the
present invention with reference to the drawings. The same or
corresponding members are denoted with the same reference numerals
in all the drawings, and their descriptions are not repeated.
[0033] Referring first to FIG. 1, a joined member manufacturing
apparatus 1 according to an embodiment of the present invention is
now described. FIG. 1 is a general configuration diagram of the
joined member manufacturing apparatus 1. The joined member
manufacturing apparatus 1 includes a first electrode (which is
hereinafter referred to as "first electrode 11") to be brought into
contact with a first member (which is hereinafter referred to as
"first member D"), a second electrode (which is hereinafter
referred to as "second electrode 12") to be brought into contact
with a second member (which is hereinafter referred to as "second
member E"), a welding power source 15, an induction heating coil
(which is hereinafter referred to as "heating coil 23"), a coil
power source 25, a housing 30 for accommodating the first electrode
11, the second electrode 12, the welding power source 15, the
heating coil 23 and the coil power source 25, and a controller 50.
Here, prior to detailed description of the joined member
manufacturing apparatus 1, the configuration of a joined member
manufactured by the joined member manufacturing apparatus 1 is
illustrated by way of example.
[0034] FIG. 2A is a perspective view of the first member D and the
second member E. FIG. 2B is a cross-sectional view of the first
member D and the second member E. FIG. 2C is a cross-sectional view
of a joined member C. The joined member C is a component obtained
by welding the first member D and the second member E together. In
this embodiment, description is made on the assumption that the
first member D is formed to have a ring-like shape and the second
member E is formed so as to have a circular cylindrical shape. The
first member D has a thick disk-like shape with a circular
cylindrical hollow portion Dh formed through its center. In the
first member D, an outer circumference of the disk and a
circumference of the hollow portion Dh are concentric with each
other. The first member D has a first joint surface Df formed by
chamfering a corner between an end face Ds and the hollow portion
Dh. The first joint surface Df corresponds to a joint target
portion of the first member D. In this embodiment, the first member
D is made of carburized steel obtained by subjecting a ring-shaped
low-carbon steel blank to surface carburization. Thus, the first
member D is a member having a soft and tough internal structure and
hard surfaces having a possibility of undergoing quenching when
heated. Here, the expression "having a possibility of undergoing
quenching" means that the surfaces contain carbon to such an extent
as to be quenched when predetermined conditions are fulfilled.
Typically, the surfaces are quenched when heated during welding,
but may have been quenched by heating prior to welding (in a
carburized steel manufacturing factory, for example). The
predetermined conditions are different depending on the
specification of the welding machine or the type of material for
the first member D, for example.
[0035] The second member E is formed with an outer diameter
slightly larger than a diameter of the hollow portion Dh of the
first member D. The second member E has a second joint surface Ef
formed by chamfering a corner between an end face and a lateral
face. The second joint surface Ef corresponds to a joint target
portion of the second member E. The second joint surface Ef is
configured to be in surface contact with the first joint surface Df
of the first member D. In this embodiment, the second member E is
made of cast iron. In this embodiment, the joined member C is
formed by joining the first joint surface Df and the second joint
surface Ef by solid phase joining. Solid phase joining is welding
that is performed at a temperature equal to or lower than a melting
point. In this embodiment, the solid phase joining is achieved by
resistance welding. In this embodiment, the ring-shaped first joint
surface Df and the second joint surface Ef are joined almost
uniformly along their entire circumferences. Examples of
characteristics of joining involving such a ring member are as
follows: positioning is easy and jigs are simple, the shapes of
joint surfaces are simple and processing cost is low, joining can
be completed within a short period of time and cycle time is short,
and thermal distortion is less likely to occur and dimensional
accuracy after joining can be easily achieved. The joined member C
can be utilized as a component, such as a gear or shaft, in a large
drive system.
[0036] Referring again to FIG. 1, description of the joined member
manufacturing apparatus 1 is continued. The joined member
manufacturing apparatus 1 is configured to be able to perform
resistance welding of the first member D and the second member E
using the first electrode 11 and the second electrode 12. The first
electrode 11 has a first contact face 11, formed on its upper face,
with which the first member D is brought into contact. The first
contact face 11t is typically formed flat. The first electrode 11
is typically placed on a bottom face of the housing 30 such that
the first contact face 11t is horizontal. The second electrode 12
is placed above the first electrode 11, and has a second contact
face 12t, formed on its lower face, with which the second member E
is brought into contact. The second contact face 12t is typically
formed flat. The second electrode 12 is supported by an electrode
support (not shown) such that the second contact face 12t is
horizontal. The second electrode 12, supported by the electrode
support (not shown), is configured to be movable vertically and to
be able to be pressed against the first electrode 11. The first
electrode 11 and the second electrode 12 are electrically connected
to the welding power source 15.
[0037] The welding power source 15 is a device for supplying the
first electrode 11 and the second electrode 12 with an electric
current. In this embodiment, the welding power source 15 is
connected to an AC power source such as a commercial AC power
source or AC power generator, and the welding power source 15 has a
power source unit for boosting and rectifying the AC electric power
from the AC power source, a capacitor for storing and discharging
electrical energy, a welding transformer for converting the
electric current supplied from the power source unit and the
capacitor into a large electric current, and a switch component
disposed upstream of the welding transformer. The welding power
source 15 is configured to be able to discharge the energy charged
in the capacitor instantaneously. Thus, in welding process using
the welding power source 15, a large electric current can be
obtained within a short period of time and welding can be achieved
with less impact of heat. In addition, in the welding power source
15, an input power source (AC power source) with a relatively small
capacity suffices. The welding power source 15 is configured to be
able to set the magnitude of the electric current that is supplied
to the first electrode 11 and the second electrode 12 as
appropriate.
[0038] The heating coil 23 is for performing high-frequency
induction heating of a portion where the first member D and the
second member E have been welded to each other. High-frequency
induction heating is a form of electromagnetic heating. The heating
coil 23 is wound into a circle with a diameter slightly larger than
the outer diameter of the circular cylindrical second member E. The
expression "slightly larger" used herein means a size that allows
the heating coil 23 to exert the effect of an eddy current that is
generated by passing an electric current through the heating coil
23 on a welded portion between the first member D and the second
member E without contact with the second member E. The heating coil
23 is supported by a coil support (not shown), and placed between
the first electrode 11 and the second electrode 12. The heating
coil 23, supported by the coil support (not shown), is configured
to be movable (vertically in this embodiment) along an imaginary
straight line connecting the first electrode 11 and the second
electrode 12. The heating coil 23 is connected to the coil power
source 25. The coil power source 25 is a device for generating an
electric current passed through the heating coil 23. In this
embodiment, the coil power source 25 is connected to an AC power
source such as a commercial AC power source or AC power generator,
and includes a high-frequency electric current generation part that
converts the AC electric current received from the AC power source
into a high-frequency electric current with an inverter or the
like. The coil power source 25 is configured to be able to set the
frequency, magnitude and duration of the electric current passed
through the heating coil 23 as appropriate.
[0039] The housing 30 accommodates devices constituting the joined
member manufacturing apparatus 1 including the first electrode 11,
the second electrode 12, the welding power source 15, the heating
coil 23 and the coil power source 25. The joined member
manufacturing apparatus 1, which is constituted in this way, can be
easily transported as one unit. The housing 30 has an opening 31
through which the first member D and the second member E, and the
joined member C can be put into and taken out of the housing
30.
[0040] The controller 50 is a device for controlling operation of
the joined member manufacturing apparatus 1. The controller 50 is
connected to the electrode support (not shown) and the coil support
(not shown) via signal cables respectively, and is configured to be
able to separately move the second electrode 12 and the heating
coil 23 vertically. The controller 50 is also connected to the
welding power source 15 via a signal cable, and is configured to be
able to control the supply and shutoff of electric current to the
first electrode 11 and the second electrode 12, and the magnitude
of the electric current supplied to the first electrode 11 and the
second electrode 12. The controller 50 is also connected to the
coil power source 25 via a signal cable, and is configured to be
able to control the supply and shutoff of electric current to the
heating coil 23 and the frequency, magnitude and duration of the
electric current passed through the heating coil 23. The controller
50 is typically attached to the housing 30 either inside or outside
the housing 30 but may be installed at a location remote from the
housing 30 and configured to operate the joined member
manufacturing apparatus 1 remotely.
[0041] Referring to FIG. 3, a method for manufacturing a joined
member according to an embodiment of the present invention is now
described. FIG. 3 is a schematic view, illustrating a procedure to
manufacture the joined member C. It is premised that the method for
manufacturing the joined member C described below is carried out by
the joined member manufacturing apparatus 1 described previously.
In other words, the following description also serves as a
description of the working of the joined member manufacturing
apparatus 1. The joined member C can be manufactured by a method
other than operating the joined member manufacturing apparatus 1.
In the following description of a method for manufacturing a joined
member, when mention is made of detailed configuration of the
joined member manufacturing apparatus 1 and the joined member C,
reference is made to FIG. 1 and FIG. 2 as appropriate.
[0042] When the first member D and/or the second member E are not
in the housing 30, the second electrode 12 and the heating coil 23
are standing by at an upper part in the housing 30. To start
manufacturing the joined member C, the first member D and the
second member E are first put into the housing 30 through the
opening 31. At this time, the first member D is first mounted on
the first contact face 11t of the first electrode 11 with the first
joint surface Df facing upward, and then, the second member E is
mounted on the first member D with the second joint surface Ef in
contact with the first joint surface Df (contact-placing step:
refer to FIG. 3A). In this way, the first member D and the second
member E are placed in the joined member manufacturing apparatus 1
(members placing step). After the first member D and the second
member E are mounted on the first contact face 11t, the controller
50 moves the heating coil 23 downward via the coil support (not
shown) to place the heating coil 23 in the vicinity of where the
end face Ds of the first member D meets the lateral face of the
second member E with the second member E extending through the
inside of the heating coil 23. At this time, the heating coil 23 is
placed so as not to contact the first member D and the second
member E.
[0043] Then, the controller 50 moves the second electrode 12
downward via the electrode support (not shown) to bring the second
contact face 12t of the second electrode 12 into contact with the
second member E, and further presses the second member E downward
against the first member D (refer to FIG. 3B). Then, the controller
50 activates the welding power source 15 to pass an electric
current 1 between the first electrode 11 and the second electrode
12 (electrode energizing step) with simultaneous application of
pressure to the contacted portions of the first joint surface Df
and the second joint surface Ef. As a result, the contacted
portions of the first joint surface Df and the second joint surface
Ef are welded to each other (welding step: refer to FIG. 3C). The
welding carried out here is resistance welding that uses Joule heat
generated by the contact resistance between the first member D and
the second member E, which are both made of a metal material, to
join them. In this embodiment, because a capacitor that
instantaneously discharges electrical energy is included in the
welding power source 15, a relatively large electric current is
obtained within a short period of time (within several dozen
milliseconds, for example) and the first joint surface Df and the
second joint surface Ef undergo solid phase joining (in the
following, the portion where welding between the first joint
surface Df and the second joint surface Ef has been completed is
referred to as "welding-completed portion F"). At this time, the
first joint surface Df side of the welding-completed portion F is
quenched by heat from the welding. The quenched portion has an
increased hardness (a Vickers hardness of about 800, for example),
but is vulnerable to impacts and may suffer from cracks.
[0044] Previously, in order to eliminate the possibility that
quenching causes occurrence of cracks, a carburized layer having a
possibility of undergoing quenching is removed only from the
portion to be joined and its vicinity. However, the carburized
layer is so hard that its removal takes significant effort. As an
alternative for preventing a joined portion from being quenched, an
anti-carburization treatment, which prevents formation of a
carburized layer during carburization, can be employed. However,
such an anti-carburization treatment also takes a lot of man-hours.
When the fact is taken into consideration that it takes significant
effort to prevent formation of a carburized layer on a portion to
be joined as described above, one possible way to inhibit
occurrence of cracks caused by quenching is to carry out joining by
welding without preventing a carburized layer from being formed on
the portion to be joined, and then to pass an electric current
again through the joined portion to temper it after joining by
welding is achieved. In some cases, however, the Vickers hardness
of the joined portion may not be decreased to a level required for
the joined member C as a product even when an electric current is
passed through the joined portion again to temper it. The present
inventors found that the hardness of a joined portion can be
decreased to a level required for the joined member C as a product
by the following treatment even when welding is carried out with a
carburized layer formed on a portion to be joined and the joined
portion is quenched. In the following, the steps following the
welding in the method for manufacturing a joined member according
to this embodiment are described.
[0045] The controller 50 maintains the application of pressure to
the welding-completed portion F even after completion of the
welding between the first joint surface Df and the second joint
surface Ef. This prevents the stress on the welding-completed
portion F from being released to cause occurrence of cracks in the
quenched portion. In other words, maintaining the application of
pressure to the welding-completed portion F even after the
completion of welding corresponds to a crack-inhibition step. The
controller 50 activates the coil power source 25 to pass an
electric current through the heating coil 23 (coil energizing step)
while performing the crack-inhibition step. Then, an eddy current Q
is generated in the welding-completed portion F, and the
welding-completed portion F undergoes high-frequency induction
heating (electromagnetic heating step: refer to FIG. 3D). The
welding-completed portion F is tempered by the high-frequency
induction heating. The controller 50 adjusts the frequency,
magnitude and duration of the electric current that is supplied
from the coil power source 25 to the heating coil 23 to temper the
welding-completed portion F by applying an amount of heat necessary
to decrease the hardness of the welding-completed portion F to a
level required for the joined member C as a product. At this time,
when a depth of the welding-completed portion F (the distance from
the heating coil 23 to the farthermost portion of the
welding-completed portion F) is large, appropriate tempering may
not be achieved. In this embodiment, high-frequency induction
heating of the welding-completed portion F is performed according
to the following procedure.
[0046] FIG. 4A is a partial cross-sectional view, illustrating a
progress of tempering by high-frequency induction heating, and FIG.
4B is a partial cross-sectional perspective view of the
welding-completed portion F. The heating coil 23 is placed in the
vicinity of a first edge Sn forming a boundary between the end face
Ds of the first member D and the lateral face of the second member
E. An opposite edge Sf forming a boundary between a face of the
hollow portion Dh of the first member D and an end face of the
second member E is located remotest from the heating coil 23 in the
welding-completed portion F. When the heating coil 23 is used to
perform high-frequency induction heating, the controller 50 first
increases the output from the coil power source 25 to a relatively
high level to heat a region including the welding-completed portion
F on the opposite edge Sf side and its vicinity (which is
hereinafter referred to as "opposite edge-side region Jf") to a
temperature suitable for its tempering until the opposite edge-side
region Jf is tempered. At this time, a region including the
welding-completed portion F on the first edge Sn side and its
vicinity (which is hereinafter referred to as "first edge-side
region Jn") has a temperature higher than that of the opposite
edge-side region Jf, and may be typically quenched rather than
tempered. After the tempering of the opposite edge-side region Jf
is completed, the controller 50 once shuts off the output from the
coil power source 25 to bring the first edge-side region Jn into a
quenched state. Then, the controller 50 increases the output from
the coil power source 25 so that the first edge-side region Jn can
have a temperature suitable for its tempering, and heats the first
edge-side region Jn to the temperature suitable for its tempering
until the first edge-side region Jn is tempered. Usually, the
output from the coil power source 25 is lower when the first
edge-side region Jn is tempered than when the opposite edge-side
region Jf is tempered. As described above, in this embodiment, the
entire welding-completed portion F can be tempered with one heating
coil 23 placed in the vicinity of the first edge Sn. Because
high-frequency induction heating is direct heating by an induced
electric current, tempering is completed within a shorter period of
time compared to ordinary tempering. In addition, because
high-frequency induction heating allows local heating, only the
vicinity of the welding-completed portion F can be heated to be
tempered without causing any adverse effect on the surrounding
carburized layer. In other words, for example, tempering in a
furnace or the like takes a longer time and may cause even portions
that need hardness (such as teeth of a gear) to be also tempered.
However, high-frequency induction heating can avoid such adverse
effects.
[0047] Referring again mainly to FIG. 3, description of the method
for manufacturing a joined member is continued. When tempering of
the welding-completed portion F by high-frequency induction heating
is completed, the controller 50 moves the second electrode 12
upward via the electrode support (not shown) to release the
pressure on the welding-completed portion F. Because the
welding-completed portion F, which had been quenched by the
welding, has been subsequently tempered by high-frequency induction
heating, the welding-completed portion F can avoid occurrence of
cracks even when the pressure is released. Then, the controller 50
moves the heating coil 23 upward via the coil support (not shown)
(refer to FIG. 3E). After that, the manufactured joined member C is
taken out of the housing 30 through the opening 31.
[0048] As described above, according to the joined member
manufacturing apparatus 1 and the method for manufacturing a joined
member according to this embodiment, when the portion where the
first joint surface Df meets the second joint surface Ef is
quenched by welding, the quenched portion is tempered by
high-frequency induction heating. Thus, the hardness of the
welding-completed portion F can be decreased to a level required
for the joined member C as a product and occurrence of cracks in
the welding-completed portion F can be inhibited.
[0049] Referring next to FIG. 5, an apparatus 1A for manufacturing
joined member according to a modification of the embodiment of the
present invention is described. FIG. 5 is a cross-sectional view of
heating coils and their vicinity in the apparatus 1A for
manufacturing joined member. The apparatus 1A for manufacturing
joined member includes a heating coil 23A in addition to the
configuration of the joined member manufacturing apparatus 1
described above (refer to FIG. 1). In other words, the apparatus 1A
for manufacturing joined member includes two induction heating
coils. The heating coil 23A is placed in such a position that it is
located in the vicinity of the opposite edge Sf during the
tempering by high-frequency induction heating in the
above-mentioned method for manufacturing a joined member. In other
words, the heating coil 23A is placed below an end face of the
second member E and in the hollow portion Dh of the first member D
when the first member D is mounted on the first electrode 11 with
the second joint surface Ef of the second member E in contact with
the first joint surface Df of the first member D. The heating coil
23A is connected to the coil power source 25 (refer to FIG. 1) via
a signal cable. The controller 50 (refer to FIG. 1) is configured
to be able to control the supply and shutoff of electric current to
the heating coil 23A and the frequency, magnitude and duration of
the electric current passed through the heating coil 23A separately
from those for the heating coil 23. Except for the above, the
apparatus 1A for manufacturing joined member has the same
configuration as the joined member manufacturing apparatus 1 (refer
to FIG. 1).
[0050] In a method for manufacturing a joined member according to a
modification of the embodiment of the present invention, which is
typically carried out using the joined member manufacturing
apparatus 1A, when the high-frequency induction heating as in the
above-mentioned method for manufacturing a joined member (refer to
FIG. 3) is performed (refer to FIG. 3D), the two heating coils 23
and 23A are used simultaneously, instead of the one heating coil
23, to perform the high-frequency induction heating. At this time,
the heating coil 23 primarily heats the first edge-side region Jn
and the heating coil 23A primarily heats the opposite edge-side
region Jf. In other words, the controller 50 controls the frequency
and/or magnitude and/or duration of the electric current passed
through the heating coil 23 so that the first edge-side region Jn
can be heated to a temperature suitable for its tempering and
controls the frequency and/or magnitude and/or duration of the
electric current passed through the heating coil 23A so that the
opposite edge-side region Jf can be heated to a temperature
suitable for its tempering. In this way, in this modification, the
time required for tempering by high-frequency induction heating
(electromagnetic, heating step) can be reduced by tempering the
first edge-side region Jn and the opposite edge-side region Jf
simultaneously. The steps other than the above-mentioned tempering
by high-frequency induction heating in the method for manufacturing
a joined member according to this modification are the same as
those of the manufacturing method shown in FIG. 3. The method for
manufacturing a joined member according to this modification can be
also achieved by a method other than operating the apparatus 1A for
manufacturing joined member.
[0051] In the above description, while the first electrode 11 and
the second electrode 12 and the welding power source 15 (which may
be hereinafter referred to as "electrodes, etc.") used to weld the
first member D and the second member E (which may be hereinafter
referred to as "works") together, and the heating coil 23 (and the
heating coil 23A) and the coil power source 25 (which may be
hereinafter referred to as "heating coil, etc.") used for
high-frequency induction heating of the works are accommodated in
one housing 30, these may not be accommodated in one housing 30 and
welding and high-frequency induction heating of the works may be
performed at different locations. In this case, before the pressure
on the welding-completed portion F is released in order to
transport the works from where the electrodes, etc. are located to
where the heating coil, etc. are located, the welding power source
15 has to be activated to pass an electric current again through
the welding-completed portion F in order to achieve preliminary
tempering. The preliminary tempering helps to prevent occurrence of
cracks in the quenched welding-completed portion F even when the
pressure on the welding-completed portion F is released. In other
words, passing an electric current again through the
welding-completed portion F in order to achieve preliminary
tempering corresponds to a crack-inhibition step. When welding and
high-frequency induction heating of the works can be performed at
different locations, the degree of freedom of the steps in the
method for manufacturing a joined member can be increased.
[0052] In the above description, while the second electrode 12 is
placed above the first electrode 11, the positions of the first
electrode 11 and the second electrode 12 may be reversed vertically
so that the first electrode 11 may be placed above the second
electrode 12. When the first electrode 11 is placed above the
second electrode 12, the first contact face 11t faces downward and
the second contact face 12t faces upward. Thus, when the joined
member C is manufactured, the second member E is passed through the
heating coil 23 placed above the second contact face 12t before the
second member E is mounted on the second contact face 12t. The
first member D is then mounted on the second member E, and the
first electrode 11 is moved downward to carry out resistance
welding. Then, induction heating is performed with the heating coil
23. At this time, the heating coil 23 may be moved to the vicinity
of the first edge Sn after the first member D is mounted on the
second member E, or may be fixed in advance at such a position that
it is located in the vicinity of the first edge Sn when the second
member E with the first member D mounted thereon is mounted on the
second contact face 12t. In addition, the first electrode 11 and
the second electrode 12 have not necessarily to be placed so as to
be separated vertically, and may be placed so as to be separated
horizontally. In this case, the first electrode 11 and/or the
second electrode 12 and the heating coil 23 are configured to be
movable in a horizontal direction.
[0053] In the above description, while the welding power source 15
is configured to be able to discharge the energy charged in the
capacitor instantaneously, a power source configuration used in a
welding machine other than a capacitor-type welding machine may be
employed.
[0054] In the above description, while the first member D is formed
to have a ring-like shape and the second member is formed to have
the shape of a solid circular cylinder, the second member E may not
be solid but may be hollow, and the first member D and/or the
second member E may have shapes other than those described herein.
In addition, while the first member D is described to be made of
carburized steel, the first member D may be made of high-carbon
steel that has not undergone a carburization treatment but has a
possibility of undergoing quenching by welding. While the first
member D is described to be quenched by welding, the joined member
C may be manufactured using a material that has been quenched
before being welded. In addition, while the first member D and the
second member E are described to be made of different types of
metals, the first member D and the second member E may be made of
the same type of metal. In addition, while the second member E is
described to be made of cast iron, the second member E may be also
formed of a material having a possibility of undergoing
quenching.
[0055] In the above description, while the first joint surface Df
and the second joint surface Ef are welded by resistance welding,
welding other than resistance welding, such as laser welding or
electron beam welding, may be employed. The first member D still
has a possibility of undergoing quenching when welding other than
resistance welding, such as laser welding or electron beam welding,
is employed.
[0056] In the above description, while the electromagnetic heating
for use in tempering the welding-completed portion F is
high-frequency induction heating, induction heating using an
electromagnetic wave other than a high-frequency wave may be
employed.
[0057] While an embodiment of the present invention is described in
the foregoing, this embodiment is presented as an example and is
not intended to limit the scope of the invention. This novel
embodiment can be implemented in various other modes, and various
omissions, replacements or alterations can be made without
departing from the spirit and scope of the invention. The
embodiment and modifications thereof are included in the scope and
gist of the invention and are also included within the scope of the
invention described in the claims and its equivalents.
[0058] A method for manufacturing a joined member according to the
eleventh aspect of the present invention is, as shown in FIGS. 3A,
3C and 3D, for example, a method for manufacturing a joined member
C (see FIG. 2C, for example) by joining a first member D formed of
a metal material having a possibility of undergoing quenching and a
second member E formed of a metal material, and the method includes
a contact-placing step of placing the first member D and the second
member E with a joint target portion Df of the first member D and a
joint target portion Ef of the second member E being in contact
with each other (see FIG. 3A); a welding step of welding the joint
target portions of the first member D and the second member E by
heating (see FIG. 3C); a crack-inhibition step of subjecting the
first member D after the welding step to a process for inhibiting
occurrence of cracks; and an electromagnetic heating step of
tempering a portion where the first member D and the second member
E have been welded to each other by electromagnetic heating (see
FIG. 3D).
[0059] With this configuration, even when the joined portion is
quenched by the welding step, the jointed portion can be tempered
by electromagnetic heating. Thus, occurrence of cracks in the
welded portion can be inhibited.
[0060] As for the method for manufacturing a joined member
according to the twelfth aspect of the present invention, as shown
in FIGS. 3A to 3E, for example, in the method for manufacturing a
joined member according to the eleventh aspect, the welding step is
a step of performing resistance welding of the joint target
portions of the first member D and the second member E with
simultaneous application of pressure; and the crack-inhibition step
includes maintaining the application of pressure in the welding
step.
[0061] With this configuration, because the welding and
electromagnetic heating can be performed sequentially, productivity
can be improved.
[0062] As for the method for manufacturing a joined member
according to the thirteenth aspect of the present invention, in the
method for manufacturing a joined member according to the eleventh
aspect, the welding step is a step of performing resistance welding
of the joint target portions of the first member and the second
member with simultaneous application of pressure; and the
crack-inhibition step includes heating the portion where the first
member and the second member have been welded to each other, by
passing an electric current therethrough in order to achieve
preliminary tempering.
[0063] With this configuration, because the welding and
electromagnetic heating can be performed at different locations,
the degree of freedom of steps can be increased.
[0064] As for the method for manufacturing a joined member
according to the fourteenth aspect of the present invention, as
shown in FIGS. 3D, 4A and 4B, for example, in the method for
manufacturing a joined member according to any one of the eleventh
aspect to the thirteenth aspect, electromagnetic heating step (see
FIG. 3D) is achieved by induction heating using an induction
heating coil 23, and the electromagnetic heating step includes:
placing the induction heating coil 23 in a vicinity of a first edge
Sn forming an outer circumference of a joint surface between the
first member D and the second member E; and tempering the joint
surface Jf on a side of an opposite edge Sf opposed to the first
edge Sn first and then tempering the joint surface Jn on a side of
the first edge Sn with an output from the induction heating coil 23
reduced to a level lower than that used to temper the joint surface
Jf on the side of the opposite edge Sf.
[0065] With this configuration, the entire joint surface can be
tempered with a single installation of an induction heating
coil.
[0066] As for the method for manufacturing a joined member
according to the fifteenth aspect of the present invention, as
shown in FIG. 5, for example, in the method for manufacturing a
joined member according to any one of the eleventh aspect to the
thirteenth aspect, the electromagnetic heating step is achieved by
induction heating using induction heating coils 23 and 23A, and the
electromagnetic heating step includes: placing one 23 of the
induction heating coils in a vicinity of a first edge Sn forming an
outer circumference of the joint surface between the first member D
and the second member E and the other 23A in a vicinity of an
opposite edge Sf opposed to the first edge Sn of the joint surface,
and tempering the joint surface Jn on the side of the first edge Sn
with the induction heating coil 23 placed in the vicinity of the
first edge Sn and tempering the joint surface Jf on the side of the
opposite edge Sf with the induction heating coil 23A placed in the
vicinity of the opposite edge Sf.
[0067] With this configuration, because the first edge side and the
opposite edge side of the joint surface can be tempered
simultaneously, the time required for the electromagnetic heating
step can be shortened.
[0068] A joined member manufacturing apparatus according to the
sixteenth aspect of the present invention is, as shown in FIG. 1,
for example, an apparatus for manufacturing a joined member C (see
FIG. 2C, for example) by joining a first member D formed of a metal
material having a possibility of undergoing quenching and a second
member E formed of a metal material, and the joined member
manufacturing apparatus includes a first electrode 11 to be brought
into contact with the first member D; a second electrode 12 to be
brought into contact with the second member E; and an induction
heating coil 23 for performing induction heating of a portion where
a joint target portion Df (see FIG. 2B, for example) of the first
member D in contact with the first electrode 11 and a joint target
portion Ef (see FIG. 2B, for example) of the second member E in
contact with the second electrode 12 have been contacted and joined
to each other; wherein the induction heating coil 23 is configured
to be placed between the first electrode 11 and the second
electrode 12 when the induction heating of a portion where the
first member D and the second member E have been joined to each
other is performed.
[0069] With this configuration, even when the joined portion is
quenched when the joint target portions are joined using the first
electrode and the second electrode, the jointed portion can be
tempered by induction heating by the induction heating coil. Thus,
occurrence of cracks in the joined portion can be inhibited.
[0070] As for a method for manufacturing a joined member according
to the seventeenth aspect of the present invention is, as shown in
FIGS. 1, 3A, 3C and 3D, for example, a method for manufacturing a
joined member C (see FIG. 2C, for example) with the joined member
manufacturing apparatus 1 according to the sixteenth aspect, and
the method includes a member placing step of placing the first
member D and the second member E in the joined member manufacturing
apparatus 1 (see FIG. 3A); an electrode energizing step of passing
an electric current between the first electrode 11 and the second
electrode 12 (see FIG. 3C); and a coil energizing step of passing
an electric current through the induction heating coil 23 (see FIG.
3D).
[0071] With this configuration, even when the joined portion is
quenched when the joint target portions are joined using the first
electrode and the second electrode, the jointed portion can be
tempered by induction heating by the induction heating coil. Thus,
occurrence of cracks in the joined portion can be inhibited.
[0072] All references, including publications, patent applications,
and patents, cited herein are hereby incorporated by reference to
the same extent as if each reference were individually and
specifically indicated to be incorporated by reference and were set
forth in its entirety herein.
[0073] The use of the terms "a" and "an" and "the" and similar
referents in the context of describing the invention (especially in
the context of the following claims) is to be construed to cover
both the singular and the plural, unless otherwise indicated herein
or clearly contradicted by context. The terms "comprising,"
"having," "including," and "containing" are to be construed as
open-ended terms (i.e., meaning "including, but not limited to,")
unless otherwise noted. Recitation of ranges of values herein are
merely intended to serve as a shorthand method of referring
individually to each separate value falling within the range,
unless otherwise indicated herein, and each separate value is
incorporated into the specification as if it were individually
recited herein. All methods described herein can be performed in
any suitable order unless otherwise indicated herein or otherwise
clearly contradicted by context. The use of any and all examples,
or exemplary language (e.g., "such as") provided herein, is
intended merely to better illuminate the invention and does not
pose a limitation on the scope of the invention unless otherwise
claimed. No language in the specification should be construed as
indicating any non-claimed element as essential to the practice of
the invention.
[0074] Preferred embodiments of this invention are described
herein, including the best mode known to the inventors for carrying
out the invention. Variations of those preferred embodiments may
become apparent to those of ordinary skill in the art upon reading
the foregoing description. The inventors expect skilled artisans to
employ such variations as appropriate, and the inventors intend for
the invention to be practiced otherwise than as specifically
described herein. Accordingly, this invention includes all
modifications and equivalents of the subject matter recited in the
claims appended hereto as permitted by applicable law. Moreover,
any combination of the above-described elements in all possible
variations thereof is encompassed by the invention unless otherwise
indicated herein or otherwise clearly contradicted by context.
DESCRIPTION OF REFERENCE NUMERALS AND SYMBOLS
[0075] 1 joined member manufacturing apparatus [0076] 11 first
electrode [0077] 12 second electrode [0078] 23 heating coil [0079]
C joined member [0080] D first member [0081] Df first joint surface
[0082] E second member [0083] Ef second joint surface [0084] Jf
opposite edge-side region [0085] Jn first edge-side region [0086]
Sf opposite edge [0087] Sn first edge
* * * * *