U.S. patent application number 11/278449 was filed with the patent office on 2006-10-05 for exothermic wire for bonding substrates.
This patent application is currently assigned to Federal Mogul World-Wide, Inc.. Invention is credited to Philip Kinney, Myron Schmenk, William J. Zdeblick.
Application Number | 20060219331 11/278449 |
Document ID | / |
Family ID | 37068908 |
Filed Date | 2006-10-05 |
United States Patent
Application |
20060219331 |
Kind Code |
A1 |
Kinney; Philip ; et
al. |
October 5, 2006 |
Exothermic Wire for Bonding Substrates
Abstract
An exothermic cord, foil, or ribbon is produced by first cold
drawing individual round wires of the constituent materials under a
cover gas. The cold drawing operation yields a clean surface that
is free of oxidation and other contaminants. Next, the constituent
wires are brought together and twisted, cold drawn, swaged, and/or
friction welded to create a unitary cord exhibiting intimate
contact between the constituent materials. The unitary cord may
then be used directly or further shaped to a desired form and/or
thickness. By controlling the size ratio between the cross-sections
of the constituents, a degree of control can be exercised over the
exothermic reaction characteristics. The unitary cord, once formed,
can be coated with braze and/or flux materials to aid in a
subsequent joining operation. Multiple cords can be woven together
to form a cloth structure. The exothermic assembly can be applied
in the field of gaskets to permanently affix opposing surfaces
together, such as affixing a cylinder head in an operative position
over a cylinder block.
Inventors: |
Kinney; Philip; (Royal Oak,
MI) ; Schmenk; Myron; (Lambertville, MI) ;
Zdeblick; William J.; (Ann Arbor, MI) |
Correspondence
Address: |
DICKINSON WRIGHT PLLC
38525 WOODWARD AVENUE
SUITE 2000
BLOOMFIELD HILLS
MI
48304-2970
US
|
Assignee: |
Federal Mogul World-Wide,
Inc.
Southfield
MI
|
Family ID: |
37068908 |
Appl. No.: |
11/278449 |
Filed: |
April 3, 2006 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60667999 |
Apr 4, 2005 |
|
|
|
Current U.S.
Class: |
148/527 |
Current CPC
Class: |
F02F 1/002 20130101 |
Class at
Publication: |
148/527 |
International
Class: |
C22F 1/00 20060101
C22F001/00 |
Claims
1. A method for producing a multi-stranded exothermic assembly of
the type for propagating an exothermic reaction between the strands
in response to an initiating thermal impulse, said method
comprising the steps of: providing an elongated first wire of a
constituent metallic material having a generally round
cross-section; providing an elongated second wire of a constituent
metallic material dissimilar from that of the first wire and having
a generally round cross-section; cold drawing the first wire
through a reduction die in a non-oxidating atmosphere; cold drawing
the second wire through a reduction die in a non-oxidating
atmosphere; bringing the first and second wires into contact with
one another in a non-oxidizing atmosphere; and simultaneously
plastically deforming the first and second wires together into a
unitary cord so that the surfaces of the first and second wires are
pressed into contact to facilitate a sustained propagating
exothermic reaction in response to an initiating thermal
impulse.
2. The method of claim 1, wherein said step of plastically
deforming the first and second wires includes cold drawing the
first and second wires through a reducing die.
3. The method of claim 1, wherein said step of simultaneously
plastically deforming the first and second wires includes twisting
the first and second wires together in a generally helical
pattern.
4. The method of claim 1, wherein said step of simultaneously
plastically deforming the first and second wires includes
simultaneously cold drawing and twisting the first and second wires
together.
5. The method of claim 1, wherein said step of simultaneously
plastically deforming the first and second wires includes
swaging.
6. The method of claim 5, wherein said step of simultaneously
plastically deforming the first and second wires further includes
twisting the wires into a generally helical configuration.
7. The method of claim 1, wherein said step of simultaneously
plastically deforming the first and second wires includes
ultrasonically welding the first and second wires to one
another.
8. The method of claim 7, wherein said step of simultaneously
plastically deforming the first and second wires further includes
twisting the wires in a helical configuration.
9. The method of claim 1, further including the step of applying a
material coating to the unitary cord following said step of
simultaneously plastically deforming the first and second
wires.
10. The method of claim 9, wherein said step of applying a material
coating includes coating the unitary cord.
11. The method of claim 1, further including the step of weaving a
plurality of the cords into a cloth.
12. The method of claim 1, further including the step of flattening
the unitary cord following said step of simultaneously plastically
deforming the first and second wires.
13. The method of claim 12, wherein said flattening step further
includes passing the unitary cord through a rolling mill.
14. A one-time use gasket of the type for sealing a cylinder head
to a cylinder block in an internal combustion engine, said gasket
comprising: a sheet-like body; at least one cylinder bore opening
formed in said body; at least one fluid flow passage formed in said
body, said fluid flow passage isolated from said cylinder bore
opening; and said body being fabricated from a reactive
multi-stranded exothermic assembly of the type for propagating an
exothermic reaction in response to an initiating thermal impulse,
whereby the heat produced during the exothermic reaction is
sufficient to metallurgically fuse the cylinder head to the
cylinder block while maintaining fluidic isolation between said
cylinder bore opening and said fluid flow passage.
15. The assembly of claim 14, wherein said body includes a
protruding wick.
16. The assembly of claim 14, wherein said multi-stranded
exothermic assembly consists essentially of alternating wires of a
first constituent metallic material and a second constituent
metallic material, said second constituent metallic material being
dissimilar to said first constituent metallic material.
17. The assembly of claim 16, wherein said first constituent
metallic material consists essentially of an aluminum-based
alloy.
18. The assembly of claim 16, wherein said second constituent
metallic material consists essentially of a nickel-based alloy.
19. A method for establishing a fluid-tight seal between opposing
surfaces having formed therebetween at least two discrete flow
passages, said method comprising the steps of: forming a gasket
from a reactive multi-stranded exothermic assembly of the type for
propagating an exothermic reaction in response to an initiating
thermal impulse; forming at least two spaced and isolated flow
passages in the gasket for conducting a fluid material between the
two opposing surfaces; aligning the openings in the gasket with the
flow passages in the opposing surfaces; compressing the gasket
between the opposing surfaces; initiating a propagating exothermic
reaction in the gasket body; melting the opposing surfaces in
response to the heat generated during the exothermic reaction; and
metallurgically fusing the opposing surfaces together in regions
around the flow passages to permanently seal the opposing surfaces
together while permitting fluid exchange between the isolated flow
passages.
20. The method of claim 19, wherein said step of forming a gasket
includes providing an elongated first wire of a constituent
metallic material having a generally round cross-section, providing
an elongated second wire of a constituent metallic material
dissimilar from that of the first wire and also having a generally
round cross-section, cold drawing the first wire through a
reduction die in a non-oxidizing atmosphere, cold drawing the
second wire through a reduction die in a non-oxidizing atmosphere,
bringing the first and second wires into contact with one another
in a non-oxidizing atmosphere, and simultaneously plastically
deforming the first and second wires together into a unitary cord.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This invention claims priority to U.S. Provisional
Application No. 60/667,999 filed Apr. 4, 2005.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates to an improved method of forming
exothermic materials for various applications, and for use of
exothermic material to permanently seal a cylinder head to a block
in an internal combustion engine.
[0004] 2. Related Art
[0005] Reactive multilayer foils and coatings are used in a wide
variety of applications requiring the generation of intense,
controlled amounts of heat in a planar region. Such structures
conventionally comprise a succession of substrate-supported layers
that, upon appropriate excitation, undergo an exothermic chemical
reaction that spreads across the area covered by the layers and
thus generate precisely controlled amounts of heat. Such exothermic
chemical materials are particularly useful as sources of heat for
specialized welding, soldering, and brazing operations. However,
they can also be used in other applications requiring controlled
local generation of heat, such as primers for incendiary
devices.
[0006] Reactive multilayer materials permit exothermic reactions
with controlled and consistent heat generation. The basic driving
force behind such reactions is a reduction in atomic bond energy.
When the reactive materials are ignited, the distinct layers mix
atomically, generating heat locally. This heat ignites adjacent
regions of the structure, thereby permitting the reaction to travel
the entire length of the structure, generating heat until all the
material is reacted.
[0007] In addition to reactive coatings, efforts have been made to
develop free-standing reactive layers by cold rolling.
Nickel-Aluminum multilayer reactive foils have been formed by
cold-rolling bi-layer sheets of Ni and Al, followed by repeated
manual folding and repeated cold rolling. After the first bi-layer
strip is rolled to half its original thickness, it is folded once
again to regain its original thickness and to double the number of
layers. This process is repeated many times.
[0008] The fabrication of rolled foils is time consuming and
difficult. The rolling passes introduce lubricating oil and other
contaminants, such that the surfaces of the rolled materials must
be cleaned after every pass. In addition, the manual folding of
sheet stock does not easily lend itself to large-scaled production.
When many metal layers are rolled at once, these layers can spring
back, causing separation of the layers and degradation of the
resulting foil. Such separations also permit undesirable oxidation
of interlayer surfaces and impedes unification of the layers by
cold welding.
[0009] Accordingly, there is a need for improved methods of
fabricating reactive multilayer structures, particularly for
large-scale production applications.
SUMMARY OF THE INVENTION AND ADVANTAGES
[0010] The invention comprises a method for producing a
multi-stranded exothermic assembly of the type for propagating an
exothermic reaction between the strands in response to an initial
thermal impulse. The method comprises the steps of providing
elongated first and second wires of respective constituent metallic
materials each having a generally round cross-section, cold drawing
the first and second wires through respective reduction dies in a
non-oxidizing atmosphere, bringing the first and second wires into
contact with one another in a non-oxidizing atmosphere, and
simultaneously plastically deforming the first and second wires
together into a unitary cord so that the surfaces of the first and
second wires are pressed into contact to facilitate a sustained
propagating exothermic reaction in response to an initiating
thermal impulse.
[0011] According to another aspect of this invention, a one-time
use gasket is provided of the type for sealing a cylinder head to a
cylinder block in an internal combustion engine. The one-time use
gasket comprises a sheet-like body, at least one cylinder bore
opening formed in the body, and at least one fluid flow passage
formed in the body. The fluid passage is isolated from the cylinder
bore opening. The body is fabricated from a reactive multi-stranded
exothermic assembly of the type for propagating an exothermic
reaction in response to an initiating thermal impulse. The heat
produced during the exothermic reaction is sufficient to
metallurgically fuse the cylinder head to the cylinder block while
maintaining fluidic isolation between the cylinder bore opening and
the fluid flow passage.
[0012] According to yet another aspect of this invention, a method
for establishing a fluid-tight seal between opposing surfaces
having formed therebetween at least two discrete flow passages, is
provided. The method comprises the steps of forming a gasket from a
reactive multi-stranded exothermic assembly of the type for
propagating an exothermic reaction in response to an initiating
thermal impulse, forming at least two spaced and isolated flow
passages in the gasket for conducting fluid material between the
two opposing surfaces, aligning the openings in the gasket with the
flow passages in the opposing surfaces, compressing the gasket
between the opposing surfaces, initiating a propagating exothermic
reaction in the gasket body, melting the opposing surfaces in
response to the heat generated during the exothermic reaction, and
metallurgically fusing the opposing surfaces together while
permitting fluid exchange between the isolated flow passages.
[0013] The subject invention, as expressed through these various
methods and apparatus, provides an exothermic cord, foil, ribbon or
cloth produced in a manner that is particularly conducive for
large-scale production applications. Utilizing commercially
available wire products, the subject intention allows an exothermic
assembly to be produced at lower cost as compared with prior art
exothermic foils and the like. The subject methods enable
substantially faster throughput of finished product. By controlling
the size ratio between the cross-sections of the constituents, a
degree of control can be exercised over the exothermic reaction
characteristics and, therefore, tuned to particular applications.
Accordingly, the subject invention provides a lower cost, higher
production rate technique for creating reactive multi-layer
assemblies for use in any of the known applications, including
welding, soldering, brazing, and as primers for incendiary
devices.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] These and other features and advantages and applications of
the present invention will become more readily appreciated as the
same becomes better understood by reference to the following
detailed description when considered in connection with the
accompanying drawings, wherein:
[0015] FIG. 1 is a simplified cross-sectional view of a prior art
internal combustion engine having a traditional gasket positioned
in the interface between the cylinder head and cylinder block;
[0016] FIG. 2 is a cross-sectional view as in FIG. 1, but showing
an exothermic gasket assembly disposed in the region once occupied
by the prior art gasket in preparation for an exothermic reaction
which will result in permanent attachment of the cylinder head to
the cylinder block;
[0017] FIG. 3 is a view as in FIG. 2, but showing the cylinder head
permanently affixed to the cylinder block following the exothermic
reaction;
[0018] FIG. 4 is a simplified schematic view showing the formation
of the subject exothermic assembly in a cold-drawing operation on
bulk wires;
[0019] FIG. 5 is a cross-sectional view of a single wire taken
generally along lines 5-5 of FIG. 4;
[0020] FIG. 5A is a cross-sectional view of an alternative
cross-section of a single wire, with representative bundled wires
shown in phantom;
[0021] FIG. 6 is a cross-section of the cord taken along lines 6-6
of FIG. 4;
[0022] FIG. 7 is an end view of a completed exothermic ribbon as
taken along lines 7-7 of FIG. 4;
[0023] FIGS. 8A and 8B are simplified views showing an exothermic
assembly disposed between two substrates in the sequence of before
and then during a welding or joining operation;
[0024] FIG. 9 is a simplified schematic view as in FIG. 4 but
showing an optional application of a braze or other coating
material applied to the cord and beneficial in a later joining
application;
[0025] FIG. 10 is a schematic view as in FIG. 4 yet showing another
method of tightly bundling the wires through a twisting operation
to form the exothermic cord;
[0026] FIG. 11 is yet another alternative method of tightly packing
the wires by rotary swaging;
[0027] FIG. 12 is an illustrative cross-sectional view of the
swaging die taken generally along lines 12-12 of FIG. 11; and
[0028] FIG. 13 is still another alternative method of tightly
combining the wires using an ultrasonic friction welding
technique.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0029] Referring to the Figures, wherein like numerals indicate
like or corresponding parts throughout the several views, a prior
art engine assembly is shown in FIG. 1 including a cylinder head 10
affixed to a cylinder block 12 via head bolts 14. A gasket 16 is
disposed between the head 10 and block 12, clamped under pressure
from the head bolts 14. The gasket 16 seals the internal pressure
and fluids cycling within the cylinder bore to prevent leakage and
maximize combustion efficiency.
[0030] In some engine applications, it may be desirable to
permanently seal the cylinder head 10 to the cylinder block 12
without the aid of a gasket 16. Reminiscent of prior art fixed head
engines, in which the cylinder head and cylinder block form one
inseparable unit, an engine assembly thus formed has the advantage
of eliminating the expense of a gasket 16 and its vulnerability as
a leak path over time. However, sealing a cylinder head 10 to a
cylinder block 12 without the aid of a gasket 16 is a very
difficult undertaking because there are many flow passages 17 which
must be sealed. For example, liquid coolant and liquid oil are
routed in respective passages 17 between the cylinder head 10 and
the cylinder block 12 for proper lubrication and cooling. There are
also sometimes passages provided for valve train components. The
cylinder bore itself can even be considered a flow passage If these
passages are not independently sealed in isolation from one
another, then the engine will leak fluids and there can be
contamination between the various fluids and passages.
[0031] The subject invention overcomes these issues in the manner
shown in FIGS. 2 and 3 in which an exothermic assembly, generally
indicated at 18, is strategically routed around all of the various
passages, as well as the combustion chambers. The strategically
routed exothermic assembly 18 can be in the form of a continuous,
snake-like ribbon of material laid in a course, or formed into a
sheet-like or cloth-like body member similar in appearance to
modern gasket bodies. With the cylinder head 10 firmly held in
compression as suggested by the force arrows, the exothermic
assembly 18 is ignited to accomplish a weld of the cylinder head 10
to the cylinder block 12 and thus form a fully sealed, integral
engine assembly without the use of a gasket 16. Although FIG. 2
does not show continued use of the head bolts 14, it may be
desirable to retain use of some or all of the head bolts 14 for
added integrity.
[0032] An energy source, such as the representative match 20 shown
in FIG. 2, ignites an exposed wick portion 21 of the exothermic
assembly 18, thus initiating a propagating exothermic reaction
between its interstitial layers. As an alternative to the match 20,
an electric sparking device, laser beam, or other device capable of
producing the requisite thermal impulse can be used. Because the
exothermic assembly 18 has such large interfacial areas between
alternating layers of the constituent materials (typically Ni and
Al), ignition from the flame source 20 causes the atoms or
molecules of the constituent materials to rapidly mix and combine
in a highly exothermic reaction. Once the heat is generated locally
at the ignition point, it is conducted along the assembly 18 and
initiates additional mixing, thereby sustaining the reaction. The
speed at which the reaction front proceeds depends upon the
physical properties of the constituent materials and how they are
arranged. The reaction front causes atoms to diffuse normal to the
layers themselves, with heat being conducted parallel to the
layers.
[0033] In addition to joining a cylinder head 10 to a block 12
using the exothermic assembly 18, it is possible to permanently
seal other components in an internal combustion engine using these
techniques. For example, the engine exhaust ports can be
permanently sealed to the exhaust manifold, the intake ports can be
permanently sealed to the intake manifold, or any of the various
covers or housings can be fixed in a permanently sealed condition.
Anywhere a gasket has been used in the past, and even in
non-automotive applications, the component parts can instead be
permanently fixed and sealed using the exothermic assembly 18 and
techniques here described.
[0034] The exothermic assembly 18 thus applied to permanently seal
engine components can be accomplished using prior art type
exothermic materials. However, the invention also contemplates a
novel technique for producing an exothermic assembly 18 using bulk
wires of constituent materials, as shown in FIG. 4. As mentioned
above, the constituent materials can be Ni and Al or alloys
thereof, but other materials can be used as well, including
titanium-aluminides and the like. In fact, any of the currently
known and available materials used in reactive multilayer foil
applications may be used in the context of this invention.
[0035] In FIG. 4, bulk wires of commercial grade Ni 22 and Al 24,
for example, are readily available from numerous commercial
sources. These bulk wires 22, 24 are typically formed with a
generally round cross-section. These commercially available wires
22, 24 are first cold-drawn (below 100.degree. C.) through
respective reducing dies 26. The bulk wires 22, 24 may be of any
effective size, but diameters in the range of 50 microns have
proven satisfactory. This first drawing operation, conducted under
a cover gas (such as nitrogen or argon), removes all oxides and
other contaminates from the wires 22, 24, thus providing clean
surfaces that are suited for an exothermic reaction.
[0036] As shown in FIG. 5, the first draw dies 26 may simply reduce
the original diameter of the bulk wires, thus resulting in a
smaller circular cross-section. However, the dies 26 can
alternatively impart a full or partial geometric shape to the wires
22, 24, such as shown in FIG. 5A. In this example, the first dies
26 impart a hexagonal cross-section to the wires 22, 24 which may
aid in better nesting and increased surface contact as represented
by the phantom adjacent wires. Of course, other wire shapes are
possible.
[0037] Once drawn through the first dies 26, the wires 22, 24 are
merged and drawn as a bundle through a second die 28 which squeezes
the wires 22, 24 into a cord 30. A representative cross-section of
the chord 30 is shown in FIG. 6 to illustrate that the surfaces of
the wires 22, 24 have been brought into substantial contact with
one another through plastic deformation so that a large interfacial
surface area is established between the respective wires 22, 24.
Those skilled in the art will readily appreciate that the number of
strands of wires 22, 24 can be varied substantially, and that the
five strands shown in the figures are merely illustrative. On the
minimum side, there must be at least two such wires 22, 24, whereas
there is not an effective maximum limit. Wire bundles with strand
numbers in the 10's or 100's may be used.
[0038] The cord 30 exiting the second draw die 28 can be used
immediately in an exothermic reaction in the form thus created, or
can be further shaped by progressive rolling dies 32 to create a
ribbon similar to the configuration illustrated in FIG. 7.
Alternatively, the cord 30 can be shaped into other designs or
configurations and is not limited to the flat ribbon shape shown in
FIG. 7. Likewise, it is not necessary that the resulting
cross-section be continuous. Thus, the cord 30 can be shaped by any
other means known to those skilled in the art, including stamping,
further drawing, forging, and the like.
[0039] FIGS. 8A and 8B illustrate, in simplified terms, the
sequence of welding upper 34 and lower 36 substrates using the
exothermic assembly 18 ignited by a flame source 20. Once ignited
at the wick 21, the exothermic reaction propagates along the
assembly 18, fusing together the opposing surfaces along the
way.
[0040] FIG. 9 illustrates a supplemental application technique of
the subject forming process. The result is a slightly modified
exothermic assembly 118. Here, the constituent bulk wires 122, 124
are pulled through the first draw dies 126 as in the preceding
embodiment, and then merged and pulled through the second drawing
die 128 as in FIG. 4. The cord 130 emerging from the second draw
die 128 is then directed to a coating operation where a braze
material 138, contained as a suspension or powder in a hopper 140,
is applied to the exterior surface of the cord 130 to thus encase
the exothermic assembly 11' for benefit in a later joining
operation. Instead of the braze material 138, other coatings can be
applied, such as solder, flux, or other beneficial treatments. Once
the sprayed material 138 is sufficiently solidified or dried, the
exothermic assembly 118 is ready for use in any conceivable
application (i.e., not limited to internal combustion engines).
[0041] FIG. 10 illustrates yet another alternative forming
technique for the exothermic assembly 218. In this situation, the
bulk wires 222, 224 are drawn through the first set of dies 226 and
then brought together in a twisting device, generally shown at 242.
The twisting device 242 includes a collar 244 driven by a gear
wheel 246 via a motor 248. The twisting operation takes the place
of the second draw die 228 as in FIGS. 4 and 9, to effectively
bring the wires 222, 224 tightly together to form a bulk exotherm
with good interfacial contact between the constituent wires 222,
224. The resulting cord 230 of twisted construction is ready for
use in an exothermic reaction, or can be coated with a braze
material as described in the preceding example. Alternatively, the
resulting cord 230 of twisted construction can be rolled or shaped
using progressive rollers like that shown in FIG. 4, or other
post-forming techniques, to achieve a desired shape in the
resulting exothermic assembly 218. In situations where it would be
advantages to work with a sheet of exothermic material, a cloth may
be readily formed by weaving or felting a number of exothermic
cords.
[0042] FIG. 11 illustrates the use of rotary swaging to assemble
the reactants. In this example, the second die 328 is formed in
sections 350 that can be separately actuated to "hammer" the bundle
of wires 322, 324 into a tightly packed condition, as shown in FIG.
12. The swaging die 328 can be simultaneously rotated to impart a
twist to the emerging cord 330 or simply allow the wires to remain
parallel.
[0043] FIG. 13 illustrates the use of ultrasonic welding for
joining the reactants. Here, the second die 428 is vibrated at high
frequency to surface weld the individual wires 422, 424 together.
The die 428 may also be rotated to introduce a twist in the
resulting cord 430 as in preceding examples.
[0044] It will be appreciated that all of the various assembly
techniques can be blended to form additional hybrid variations with
the resulting exothermic assembly useful in any application in
which prior art reactive multilayer foils and coatings have been
used. Thus, while the invention has been described in an
illustrative manner, it is to be understood that the terminology
which has been used is intended to be in the nature of words of
description rather than of limitation.
[0045] Obviously, many modifications and variations of the
invention are possible in light of the above teachings. It is,
therefore, to be understood that the invention may be practiced
otherwise than as specifically described.
* * * * *