U.S. patent application number 11/735098 was filed with the patent office on 2007-08-09 for bonding of materials with induction heating.
Invention is credited to Maochang Cao, Oleg S. Fishman.
Application Number | 20070181564 11/735098 |
Document ID | / |
Family ID | 30115728 |
Filed Date | 2007-08-09 |
United States Patent
Application |
20070181564 |
Kind Code |
A1 |
Fishman; Oleg S. ; et
al. |
August 9, 2007 |
Bonding of Materials with Induction Heating
Abstract
An apparatus and process are provided for bonding of materials
by induction heating of an electrically conductive material upon
which a second material is bonded. The electrically conductive
material is induction heated between a first induction heating
plate, and the combination of a frame and a second induction
heating plate that is disposed within the frame. The second
induction heating plate is removed from the surface of the
electrically conductive sheet, while the frame continues to hold
the electrically conductive sheet flat, and the second material, in
liquid form, is poured into the interior opening of the frame in
which the second induction heating plate was originally placed. The
liquid material solidifies and bonds to the electrically conductive
sheet to produce a bonded product. A continuous sheet of an
electrically conductive material may be bonded to a continuous
sheet of a second material by pressing them together and moving the
pressed together materials through an induction coil to inductively
heat the electrically conductive material and bond it with the
second material.
Inventors: |
Fishman; Oleg S.; (Maple
Glen, PA) ; Cao; Maochang; (Westampton, NJ) |
Correspondence
Address: |
PHILIP O. POST;INDEL, INC.
PO BOX 157
RANCOCAS
NJ
08073
US
|
Family ID: |
30115728 |
Appl. No.: |
11/735098 |
Filed: |
April 13, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10615150 |
Jul 8, 2003 |
7205516 |
|
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11735098 |
Apr 13, 2007 |
|
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60394515 |
Jul 9, 2002 |
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Current U.S.
Class: |
219/622 |
Current CPC
Class: |
F16C 33/14 20130101;
F16C 2223/32 20130101; Y10T 428/12493 20150115; H05B 6/105
20130101; Y10T 428/31678 20150401 |
Class at
Publication: |
219/622 |
International
Class: |
H05B 6/12 20060101
H05B006/12 |
Claims
1. An electric induction bonding apparatus comprising: a first
induction heating plate having a surface for placement of an
electrically conductive sheet, the first induction heating plate
comprising one or more first induction coils disposed within a heat
resistant material; a second induction heating plate selectively
locatable over the surface of the first induction heating plate,
the second induction heating plate comprising one or more second
induction coils disposed within a heat resistant material; a frame
disposed around the second induction heating plate, the frame
selectively locatable over the surface of the first induction
heating plate to form a dam over the surface of the first induction
heating plate; and at least one or more ac power supplies connected
to the one or more first and second induction coils.
2. The electric induction bonding apparatus of claim 1 wherein the
frame further comprises one or more third induction heating coils
disposed within a heat resistant material.
3. The electric induction bonding apparatus of claim 1 further
comprising one or more fluid cooling passages in at least the first
or second induction heating plate.
4. The electric induction bonding apparatus of claim 1 wherein the
one or more first induction coils are orthogonally oriented to the
one or more second induction heating coils.
5. The electric induction bonding apparatus of claim 1 wherein the
first or second induction heating plates further comprises one or
more temperature sensing devices disposed in the heat resistant
material.
6. A method of producing a bonded product by electric induction
heating, the method comprising the steps of: placing an
electrically conductive sheet between a first induction heating
plate and a second induction heating plate disposed within a
separable frame; supplying ac current to one or more induction
heating coils in the first and second induction heating plates to
establish magnetic fields that couple with the electrically
conductive sheet to inductively heat the sheet; separating the
first induction heating plate and the frame from the second
induction heating plate; and pouring a liquid bonding material into
the volume bounded by the frame and a surface of the electrically
conductive sheet.
7. The method of claim 6 further comprising the step of quenching
the liquid bonding material on the electrically conductive
sheet.
8. The method of claim 6 further comprising the step of cooling at
least the first induction heating plate, the second induction
heating plate, or the frame.
9. The method of claim 6 further comprising the step of sensing the
temperature of the first or second induction heating plate prior to
the step of separating the first induction heating plate and the
frame from the second induction heating plate.
10. The method of claim 6 further comprising the step of supplying
ac current to one or more induction coils in the frame.
11. An electric induction bonding apparatus comprising: a first
induction heating plate having an indented surface area for
placement of an electrically conductive sheet, the first induction
heating plate comprising one or more first induction coils disposed
within a heat resistant material; a second induction heating plate
having a surface area substantially the same as the indented
surface area of the first induction heating plate, the surface area
of the second induction heating plate selectively locatable over
the indented surface area of the first induction heating plate, the
second induction heating plate comprising one or more second
induction coils disposed within a heat resistant material; a frame
disposed around the second induction heating plate, the frame
selectively locatable over the surface of the first induction
heating plate; and at least one or more ac power supplies connected
to the one or more first and second induction coils.
12. The electric induction bonding apparatus of claim 11 wherein
the frame further comprises one or more third induction heating
coils disposed within a heat resistant material.
13. The electric induction bonding apparatus of claim 11 wherein
the one or more first induction coils are orthogonally oriented to
the one or more second induction coils.
14. The electric induction bonding apparatus of claim 11 wherein
the first or second induction heating plates further comprises one
or more temperature sensing devices disposed in the heat resistant
material.
15. A method of producing a bonded product by electric induction
heating, the method comprising the steps of: placing an
electrically conductive sheet between a first induction heating
plate and a second induction heating plate disposed within a
separable frame; supplying ac current to one or more induction
heating coils in the first and second induction heating plates to
establish magnetic fields that couple with the electrically
conductive sheet to inductively heat the sheet; pressing the
electrically conductive sheet into an indentation in the first
induction heating plate with the second induction heating plate;
moving the second induction heating plate away from the
electrically conductive sheet; and pouring a liquid bonding
material into the indentation over the electrically conductive
sheet.
16. The method of claim 15 further comprising the step of quenching
the liquid bonding material over the electrically conductive
sheet.
17. The method of claim 15 further comprising the step of supplying
ac current to one or more induction coils in the frame.
18. The method of claim 15 further comprising the step of cooling
at least the first induction heating plate, the second induction
heating plate, or the frame.
19. The method of claim 15 further comprising the step of sensing
the temperature of the first or second induction heating plate
prior to the step of pressing the electrically conductive sheet
into the indentation in the first induction heating plate with the
second induction heating plate.
20. The method of claim 15 further comprising the step of sensing
the temperature of the first or second induction heating plate
prior to the step of moving the second induction heating plate away
from the electrically conductive sheet.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a divisional application of application Ser. No.
10/615,150, filed Jul. 8, 2003, which claims the benefit of U.S.
Provisional Application No. 60/394,515, filed Jul. 9, 2002, both of
which are hereby incorporated herein by reference in their
entireties.
FIELD OF THE INVENTION
[0002] The present invention relates to the use of magnetic
induction heating of a material to bond multiple materials
together.
BACKGROUND OF THE INVENTION
[0003] Bonded materials are used in many applications. For example,
a slide bearing may be formed from a bonded composition that
consists of a metal backing plate and a bearing surface material
that is bonded to the plate. The bearing surface material may be a
metal composition such as a copper or an aluminum alloy. Slide
bearings are linear or rotary in form. Linear slide bearings are in
sheet form, whereas rotary slide bearings are in cylindrical or
half-cylindrical form. Half-cylindrical slide bearings are used in
pairs for applications such as journal bearings in internal
combustion engines.
[0004] One method of producing slide bearings involves a continuous
process line wherein the feedstock for the metal backing plate is a
continuous roll of sheet steel. The continuous roll of sheet steel
is fed through heat treating furnaces and further conditioned
before the bearing surface material is applied to it. Raised edge
lips are formed on the longitudinal edges of the continuous sheet
and the bearing surface material, in a liquid form, such as a
molten copper or aluminum alloy, is poured onto the sheet. The
molten alloy solidifies and is bonded to the sheet, and can be
quench treated. Subsequent milling controls the thickness of the
bearing surface material. The sheet is cut into desired sizes for
slide bearing applications. For rotary slide bearings, the cut
pieces are further formed into a cylindrical shape. Economically,
the process must operate as an uninterrupted line process, since
stopping the line and restarting the line involves a substantial
effort in repeatedly bringing the line's furnaces to operating
temperature. Therefore there exists the need for a method of
bonding metals in a batch process for applications such as slide
bearings or in a continuous process without liquid or molten form
of bearing material.
BRIEF SUMMARY OF THE INVENTION
[0005] In one aspect, the present invention is an apparatus for,
and method of, producing a bonded product. An electrically
conductive sheet is placed between a first induction heating plate,
and the combination of a frame and a second induction heating plate
disposed within the frame, and inductively heated. The second
induction heating plate is moved away from the electrically
conductive sheet. A liquid bonding composition, such as a molten
metal, is poured into the open interior space of the frame over the
top of the electrically conductive sheet wherein it solidifies and
bonds to the electrically conductive sheet to produce a bonded
product. Optionally the electrically conductive sheet may be placed
in an indentation in the first induction heating plate which also
serves to contain the liquid bonding composition.
[0006] In another aspect, the present invention is an apparatus
for, and method of, continuously producing a bonded product by
pressing together a continuous electrically conductive sheet and a
continuous bonding material sheet, and advancing the pressed
together sheets through an induction coil to heat the electrically
conductive sheet and bond the bonding material sheet to the
electrically conductive sheet. Alternatively two continuous bonding
material sheets are disposed between two electrically conductive
sheets, pressed together and advanced through an induction coil to
heat the two electrically conductive sheets and bond each of the
bonding material sheets to its adjacent electrically conductive
sheet.
[0007] These and other aspects of the invention are set forth in
this specification and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The figures, in conjunction with the specification and
claims, illustrate one or more non-limiting modes of practicing the
invention. The invention is not limited to the illustrated layout
and content of the figures in the drawings.
[0009] FIG. 1 is an isometric view of one example of an apparatus
of the present invention for bonding materials with induction
heating.
[0010] FIG. 2 is an isometric view illustrating one example of an
arrangement of induction coils for the apparatus shown in FIG.
1.
[0011] FIG. 3 is a front elevational view of the apparatus shown in
FIG. 1.
[0012] FIG. 4 is a side elevational view of the apparatus shown in
FIG. 1.
[0013] FIG. 5 is a top view of the apparatus shown in FIG. 1,
further illustrating the arrangement of induction coils shown in
FIG. 2.
[0014] FIG. 6 is a side elevational view of another example of an
apparatus of the present invention for bonding materials with
induction heating.
[0015] FIG. 7 is a side elevational view of another example of an
apparatus of the present invention for bonding materials with
induction heating.
[0016] FIGS. 8(a), 8(b) and 8(c) illustrate another example of the
present invention for bonding materials with induction heating.
DETAILED DESCRIPTION OF THE INVENTION
[0017] Referring now to the drawings, wherein like numerals
indicate like elements, there is shown in FIG. 1 through FIG. 5,
one example of apparatus 10 of the present invention for bonding of
materials with induction heating. Apparatus 10 includes first
induction heating plate 12, frame 14 and second induction heating
plate 16. First and second induction heating plates 12 and 16, and
frame 14, are formed from a heat resistant, non-electrically
conductive material, such as a ceramic composition. First plate
induction coil 18 is disposed in first induction heating plate 12;
frame induction coil 20 is disposed in frame 14; and second plate
induction coil 22 is disposed in second induction heating plate 16.
When a castable material, such as a ceramic composition, is used
for the heating plates and frames, the coils may be embedded in the
heating plates and frame during the casting process.
[0018] The induction coils are arranged to form a transverse
induction coil assembly for inductively heating an electrically
conductive sheet 90 placed between the first induction heating
plate, and the combination of the frame and second induction
heating plate when the second induction heating plate is inserted
into the frame. While the sheet is generally referred to as a metal
sheet, any electrically conductive material may be used. The
particular arrangement of coils shown in the figures illustrates
one non-limiting example of transverse flux coil arrangements that
can be used in the present invention. The illustrated induction
coils may be fluid (liquid or gas) cooled by circulation of a
cooling fluid, such as water, through hollow induction coils or
separate cooling coils in the heating plates and frame. In some
examples of the invention, an induction coil may not be necessary
in frame 14.
[0019] Metal sheet 90 is placed upon the top surface of first
induction heating plate 12. The dimensions of metal sheet 90 are
such that when frame 14 is placed over the top surface of first
induction heating plate 12, the perimeter of the metal sheet will
extend beyond the interior open space in frame 14 to establish a
metal sheet contact surface around the metal sheet's perimeter that
is sandwiched between the top surface of the first induction
heating plate 12 and the bottom surface of frame 14.
[0020] With metal sheet 90 positioned on the surface of first
induction heating plate 12, as described above, frame 14 and second
induction heating plate 16 are placed over the top surface of the
first induction heating plate 12 and the metal sheet. The interior
open space in frame 14 is sized to allow the fitting of second
induction heating plate 16 so that the bottom surface of the second
induction heating plate 16 makes contact with metal sheet 90. With
the frame and second induction heating plate placed over metal
sheet 90, suitable ac current is supplied from one or more power
sources to first plate induction coil 18, frame induction coil 20,
and second plate induction coil 22. The magnetic field created by
ac current flow in the first plate induction coil 18 inductively
penetrates and heats into the facing side of metal sheet 90,
whereas the magnetic fields created by ac current flow in the frame
induction coil and second plate induction coil inductively
penetrate and heat into the opposing side of the metal sheet. As
best illustrated in FIG. 5, the orthogonal orientation of the first
plate induction coil to the combination of the frame and second
plate induction coils provides a crisscross induction heating
pattern that enhances uniform heat penetration of the sheet.
Pressing the metal sheet between the first and second induction
heating plates prevents surface distortion of the sheet as it is
heated.
[0021] When metal sheet 90 has been inductively heated to a desired
temperature, second induction heating plate 16 is raised at least a
sufficient distance to allow pouring of a molten metal composition,
such as a copper or aluminum alloy, onto the top surface of the
heated metal sheet. The temperature of the metal sheet may be
sensed by one or more sensors, such as contact thermocouples
embedded in the first and/or second induction heating plates to
determine when the sheet has been heated to the desired
temperature. For example, if the metal sheet is steel, it is heated
to approximately 2,100.degree. F. for casting of a molten alloy,
such as bronze, onto its surface. While the term "molten metal" or
"molten alloy" is used, any liquid material capable of bonding with
the heated electrically conductive sheet may be used. Frame 14
remains in place to hold the metal sheet flat and to provide a dam
for the molten metal composition. The molten metal may be ported
through one or more openings in frame 14, or poured, into the
interior open space in frame 14 which was previously occupied by
the second induction heating plate. After pouring a quantity of
molten metal over the top surface of the metal sheet, the metal
will bond with the sheet as it cools. Alternatively, the metal can
be quenched by injecting a quench fluid or gas into the interior
open space in the frame over the top surface of the cooled molten
metal. The quench material may be ported through one or more
openings in frame 14, or poured, into the interior open space in
frame 14. The now solidified molten metal is bonded to the metal
sheet to form a bonded metal product, and frame 14 can be removed
from over the top surface of first induction heating plate 12. The
interior surface wall of frame 14 may be skewed towards its outer
wall in the region where the molten metal is poured to facilitate
removal of the frame. Additionally the same region of the wall may
be specially treated with a coating that will inhibit bonding of
the molten metal to the wall of the frame. By way of example, and
not limitation, a typical range of thickness of the metal sheet is
approximately 3.5 to 19 mm, and a typical range of thickness of the
cast metal on the metal sheet is approximately 2.5 to 5.0 mm.
Further working of the product can include milling for thickness
control of the product. If the product is used as slide bearings,
the product is appropriately cut to the desired dimensions. For
rotary slide bearings, the cut product is then worked to a
cylindrical shaped.
[0022] In an alternative embodiment of the invention, the top
surface of first induction heating plate 12, rather than being
flat, is indented for an area approximately equal to the surface
area of the bottom surface of second induction heating plate 16. In
this arrangement, after metal sheet 90 has been heated, the second
induction heating plate can be moved towards the metal sheet to
apply sufficient pressure on the heated sheet to force it into the
indentation in the first induction heating plate. In this example,
the frame does not generally provide a dam for the molten metal
composition that is poured over the top of the sheet since the
raised edges of the indented metal sheet and/or the walls of the
indentation will serve as a dam for the molten metal composition.
In this example of the invention, the frame serves as a means for
holding the metal sheet in place during induction heating and
molten metal pour after the sheet is pressed into the indentation
in the first induction heating plate.
[0023] In other examples of the invention longitudinal flux coils,
such as solenoidal coils, may be utilized. For example, as
illustrated in FIG. 8(a), solenoidal induction coil 21 is disposed
in inductor assembly 23. Metal sheet 90 is inserted into
indentation 25 in first heat resistant plate 13. Second heat
resistant plate 17 is placed over the first ceramic plate and the
enclosed metal sheet is inserted into inductor assembly 23 as shown
in FIG. 8(b) wherein it is inductively heated by a magnetic field
established when as current flows through coil 21. After the metal
sheet reaches the desired temperature, the enclosed metal sheet is
removed from the inductor assembly, and the second heat resistant
plate is removed, as shown in FIG. 8(c), so that the molten metal
can be poured over the metal sheet in the indentation.
[0024] In another example of apparatus 11 of the present invention
for bonding of materials with induction heating, as illustrated in
FIG. 6, a continuous supply of base metal sheet 92 is provided from
base metal sheet supply roll 30 and a continuous supply of bond
material sheet 94 is provided from bond material sheet supply roll
32. Steel is a suitable, but non-limiting, composition of the base
metal sheet, and bronze is a suitable, but non-limiting,
composition of the bond material sheet. Suitable joining and
conveying means, such as rollers 36 press metal sheet 92 and bond
material sheet 94 together and advance it through one or more
induction coils 38 wherein the magnetic field established by an ac
current flow through the coils inductively heats and bonds the bond
material sheet to the base metal sheet. The one or more induction
coils may be of any suitable configuration, including transverse
flux or longitudinal flux coils, or a combination thereof. Since
the induced current flows in the bond material sheet and returns
through the base metal sheet, the required frequency of the ac
current in the one or more induction coils is lower than that
required for the previous examples of the invention. Optionally the
bonded sheets may be quenched with a suitable quench medium
supplied through quench apparatus 40 after the bonded sheets exit
from the one or more induction coils. The bonded sheets can be
accumulated, for example, on bonded sheets product roll 42 for bulk
shipment to finishing facilities that produce, for example, slide
bearings from the product roll.
[0025] Optionally the bonded sheets may be cut into one or more
bonded products by applying suitable cutting means, such as cutting
shear 41, which is schematically shown in FIG. 6 and FIG. 7, to the
bonded sheet.
[0026] FIG. 7 illustrates an alternative to the arrangement in FIG.
6. In the example of the invention shown in FIG. 7, two bond
material sheets 94a and 94b are provided from bond material sheet
supply rolls 32a and 32b, respectively, and are disposed between
two base metal sheets 92a and 92b, which are provided from base
metal sheet supply rolls 30a and 30b. Suitable joining and
conveying means, such as rollers 36 press metal sheets 92a and 92b
together with the two bond material sheets 94a and 94b between
them, and advance the pressed sheets through one or more induction
coils 38 wherein the magnetic field established by an ac current
flow through the coils inductively heats and bonds each of the two
bond material sheets to the base metal sheet making contact with
it. Generally the melt temperature of the bond material sheet is
lower than the melt temperature of the base metal sheet. In some
arrangements the required heated temperature of the base metal
sheet may be sufficient to overheat the bond material sheet. The
arrangement shown in FIG. 7 minimizes heating of the bond material
sheets since induced currents flow only through the two opposing
base metal sheets. Consequently the required frequency of the ac
current in the one or more induction coils is lower than that
required for the previous example of the invention in FIG. 6. After
optional quenching, bonded sheets comprising base metal sheet 92a
and bond material sheet 94a is accumulated on bonded sheets product
roll 42a and bonded sheets comprising base metal sheet 92b and bond
material sheet 94b is accumulated on bonded sheets product roll
42b. Optionally a sheet of heat resistant material can be inserted
between adjacent facing sides of bond material sheets 94a and 94b
prior to induction heating to keep the two bond metal sheets from
sticking together. The sheet of heat resistant material is removed
subsequent to the step of induction heating.
[0027] The foregoing examples do not limit the scope of the
disclosed invention. The scope of the disclosed invention is
further set forth in the appended claims.
* * * * *