U.S. patent application number 10/905233 was filed with the patent office on 2006-09-21 for electromagnetic pulse welding of fluid joints.
This patent application is currently assigned to THE BOEING COMPANY. Invention is credited to David R. Bolser, Allen Fischer.
Application Number | 20060208481 10/905233 |
Document ID | / |
Family ID | 37009507 |
Filed Date | 2006-09-21 |
United States Patent
Application |
20060208481 |
Kind Code |
A1 |
Fischer; Allen ; et
al. |
September 21, 2006 |
ELECTROMAGNETIC PULSE WELDING OF FLUID JOINTS
Abstract
A metallurgically formed fluid circuit joint includes a hollow
fitting (298), a tubular conduit (297), and a metallurgically
formed tube/fitting mesh (296). The tube/fitting mesh (296)
includes a fitting portion of the hollow fitting (298) and a tube
portion of the tubular conduit (297) that is electromagnetically
formed with the fitting portion.
Inventors: |
Fischer; Allen; (Creve
Coeur, MO) ; Bolser; David R.; (Florissant,
MO) |
Correspondence
Address: |
OSTRAGER CHONG FLAHERTY & BROITMAN PC
250 PARK AVENUE, SUITE 825
NEW YORK
NY
10177
US
|
Assignee: |
THE BOEING COMPANY
100 North Riverside
Chicago
IL
|
Family ID: |
37009507 |
Appl. No.: |
10/905233 |
Filed: |
December 22, 2004 |
Current U.S.
Class: |
285/258 |
Current CPC
Class: |
Y10T 29/53987 20150115;
F16L 13/02 20130101; B21D 39/046 20130101; B21D 26/14 20130101;
B23K 20/06 20130101; F16L 13/00 20130101 |
Class at
Publication: |
285/258 |
International
Class: |
F16L 47/00 20060101
F16L047/00 |
Claims
1. A metallurgically formed fluid circuit joint comprising: a
hollow fitting; a tubular conduit; and metallurgically formed
tube/fitting mesh comprising; fitting portion of said hollow
fitting; and tube portion of said tubular conduit
electromagnetically formed with said fitting portion.
2. A fluid circuit joint as in claim 1 wherein said tubular conduit
is received at least partially within said hollow fitting.
3. A fluid circuit joint as in claim 1 wherein said tubular conduit
is received at least partially over said hollow fitting.
4. A fluid circuit joint as in claim 1 wherein said hollow fitting
prior to electromagnetic forming comprises a plurality of
grooves.
5. A fluid circuit joint as in claim 1 wherein said hollow fitting
and said tubular conduit are formed of at least one material
selected from stainless steel, aluminum, and titanium.
6. A fluid circuit joint as in claim 1 wherein the hollow fitting
prior to electromagnetic forming thereof comprises: a tube inlay
section comprising; a tube-butting edge associated with an end of
said tubular conduit; and a plurality of internal grooves.
7. A fluid circuit joint as in claim 1 wherein the hollow fitting
prior to electromagnetic forming comprises: a tube overlap region
comprising; an radius edge associated with an end of the tube; a
plurality of grooves; and a break edge guiding insertion of the
fitting into the tube.
8. A magnetic forming system for creating a fluid circuit joint
between a tube and a fitting comprising: an induction coil forming
an electromagnetic current; and a field concentrator assembly
electrically coupled to said induction coil and forming a
electromagnetic field in response to said electromagnetic current,
said field concentrator assembly comprising: field concentrator
focusing said electromagnetic current to form said electromagnetic
field; and nest configured to contain the tube at least partially
positioned within the fitting; aid field concentrator imposing said
electromagnetic field on the fitting to metallurgically weld the
fitting to the tube to form the fluid circuit joint.
9. A system as in claim 8 wherein said field concentrator imposes
said electromagnetic field to compress the fitting on the tube to
form the fluid circuit joint.
10. A system as in claim 8 wherein said nest resides at least
partially within said field concentrator.
11. A system as in claim 8 further comprising a mandrel residing
within the tube and inwardly constraining the tube and the
fitting.
12. A system as in claim 8 further comprising: a controller
generating a current pulse signal; and a current supply circuit
generating an energy pulse in response to said current pulse
signal; said induction coil generating said electromagnetic field
in response to said current pulse.
13. A system as in claim 8 wherein said field concentrator imposes
said electromagnetic field to compress said fitting prior to
metallurgical welding thereof.
14. A method as in claim 8 further comprising: an end-forming
device expanding said fitting prior to insertion of said tube into
said fitting; and said field concentrator imposing said
electromagnetic field on said fitting to metallurgically weld said
fitting with said tube to form said fluid circuit joint.
15. A system as in claim 8 further comprising an insert
electrically coupled to said field concentrator and imposing said
electromagnetic field on said fitting to form said fluid circuit
joint.
16. A system as in claim 15 wherein said field concentrator is
external to said nest and said insert is coupled at partially
within said nest.
17. A magnetic forming system for creating a fluid circuit joint
between a tube and a fitting comprising: an end former expanding at
least a portion of the tube; an induction coil forming an
electromagnetic current; and a field concentrator assembly
electrically coupled to said induction coil and forming a
electromagnetic field in response to said electromagnetic current,
said field concentrator assembly comprising: a concentrator
focusing said electromagnetic current to form said electromagnetic
field; and a nest configured to contain the fitting at least
partially positioned within said portion; said field concentrator
imposing said electromagnetic field on the tube to metallurgically
weld the tube to the fitting to form the fluid circuit joint.
18. A system as in claim 17 wherein said field concentrator imposes
said electromagnetic field to compress said portion on the fitting
to form the fluid circuit joint.
19. A system as in claim 17 wherein the fitting comprises a tube
overlap region having at least one groove.
20. A system as in claim 17 wherein the fitting comprises: a tube
overlap region comprising; a radius edge associated with an end of
the tube; a plurality of grooves; and a break edge guiding
insertion of the fitting into the tube.
21. A system as in claim 17 further comprising a mandrel residing
within the fitting and inwardly constraining the tube and the
fitting.
22. A system as in claim 17 further comprising: a controller
generating a current pulse signal; and a current supply circuit
generating a current pulse in response to said current pulse
signal; said induction coil generating said electromagnetic field
in response to said current pulse.
23. A system as in claim 17 wherein said field concentrator imposes
said electromagnetic field to compress said tube prior to
metallurgical welding thereof.
24. A system as in claim 17 further comprising an insert
electrically coupled to said field concentrator and imposing said
electromagnetic field on said tube to form said fluid circuit
joint.
25. A system as in claim 24 wherein said field concentrator is
external to said nest and said insert is coupled at partially
within said nest.
Description
RELATED APPLICATION
[0001] The present invention is related to U.S. Patent Application
(Attorney Docket Numbers 03-0722) entitled "Magnetic Field
Concentrator for Electromagnetic Forming and Magnetic Pulse Welding
of Fluid Joints", U.S. Patent Application (Attorney Docket Numbers
04-1054/04-1055/90-79) entitled "Electromagnetic Mechanical Pulse
Forming of Fluid Joints for Low-Pressure Applications", and U.S.
Patent Application (Attorney Docket Number 04-0791) entitled
"Electromagnetic Mechanical Pulse Forming of Fluid Joints for
High-Pressure Applications", which are incorporated by reference
herein.
TECHNICAL FIELD
[0002] The present invention generally relates to the solid state
coupling of metallic tubes and fittings. More specifically, the
present invention is related to a metallurgical coupling of the
tubes and the fittings using magnetic interaction.
BACKGROUND ART
[0003] Metallic tubes are commonly used to carry fluid in the form
of gas or liquid throughout various fluid circuits in many
industries. This is especially true in the aerospace industry, due
to the lightweight and strong mechanical features of the metallic
tubes. For example, thin-walled aluminum and stainless steel tubing
is often utilized within an aircraft to carry oxygen and hydraulic
fluid for various applications, such as to breathing apparatuses
and to and from vehicle brakes.
[0004] The fluid circuits typically contain a vast number of
interlock joints, which reside between the tubing and the end
fittings, such as ferrules. The current technique used to join the
different sized tubes and ferrules, is referred to as a roller
swaging process. During this process, a tube is inserted into a
ferrule while the ferrule is constrained using a clamp. The tube is
then expanded into the ferrule using a roller. The inner walls of
the ferrule typically contain grooves within which the tube is
expanded. An interlock is created between the tube and the ferrule
due to the expansion and deformation of the tube against the inner
walls and into the grooves of the ferrule.
[0005] Another technique that is commonly used to join metallic
tubes to end fittings is referred to as Gas Tungsten Arc Welding
(GTAW), which is a fusion welding process. The formed joints
produced from fusion welding are often rejected by penetrant
inspection, pressure testing, or by radiographic inspection and
must be weld repaired. A weld formed joint may need to be repaired
as many as three times, at significant costs.
[0006] A desire exists to increase the operating lifetime of a
mechanical or fluid tight joint. Thus, there exists a need for an
improved leak tight joint between a tube and a ferrule and a
technique for forming the leak tight joint that may be applied to
various fluid circuit applications. It is desirable that the
improved technique be economical, have an associated quick
production set-up time, and account for different sized tube and
ferrule combinations.
SUMMARY OF THE INVENTION
[0007] The present invention satisfies the above-stated desires and
provides a leak tight joint utilizing magnetic interactions to form
a metallurgically formed tube/fitting mesh.
[0008] One embodiment of the present invention provides a
metallurgically formed fluid circuit joint that includes a hollow
fitting, a tubular conduit, and a metallurgically formed
tube/fitting mesh. The tube/fitting mesh includes a fitting portion
of the hollow fitting and a tube portion of the tubular conduit
that is electromagnetically formed with the fitting portion.
[0009] The embodiments of the present invention provide several
advantages. One such advantage is the provision of a metallugically
formed fitting and tube joint. Metallurgical forming or welding of
a fitting and a tube provides a single component tube/fitting
joint, wherein wall portions of the tube and the fitting are
combined into a single shared welded wall element. The single
welded element is leak tight since it is formed by the
metallurgical combination of the walls of the tube and of the
fitting.
[0010] Furthermore, the present invention provides joint forming
techniques with improved repeatability, with quick assembly times,
that do not require lubrication to form, and that have low
associated scrap rates. The scrap rates, as a result of the joint
forming techniques, is approximately zero.
[0011] Other features, benefits and advantages of the present
invention will become apparent from the following description of
the invention, when viewed in accordance with the attached drawings
and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a block diagrammatic view of a magnetic forming
system in accordance with an embodiment of the present
invention.
[0013] FIG. 2A is a cross-sectional side view of a insert/nest
assembly that may be incorporated into the system of FIG. 1 in
accordance with an embodiment of the present invention.
[0014] FIG. 2B is a front half cross-sectional view of the
insert/nest assembly of FIG. 2A.
[0015] FIG. 3A is a cross-sectional side view of a insert/nest
assembly that may be incorporated into the system of FIG. 1 in
accordance with another embodiment of the present invention.
[0016] FIG. 3B is a front half cross-sectional view of the
concentrator/nest assembly of FIG. 3A.
[0017] FIG. 4A is a cross-sectional side view of a insert/nest
assembly that may be incorporated into the system of FIG. 1 in
accordance with still another embodiment of the present
invention.
[0018] FIG. 4B is a front half cross-sectional view of the
concentrator/nest assembly of FIG. 4A.
[0019] FIG. 5A is a cross-sectional side view of an insert/nest
assembly that may be incorporated into the system of FIG. 1 in
accordance with another embodiment of the present invention.
[0020] FIG. 5B is a front half cross-sectional view of the
concentrator/nest assembly of FIG. 5A.
[0021] FIG. 6 is a side cut-away view of a tube/fitting coupling
incorporating a tube/fitting joint formed using the assemblies of
FIG. 2A or 3A.
[0022] FIG. 7A is a half-side cross-sectional view of a
tube/fitting coupling incorporating a tube/fitting joint prior and
subsequent to magnetic formation using the assembly of FIG. 4A.
[0023] FIG. 7B is a side cut-away view of a tube/fitting coupling
incorporating a tube/fitting joint subsequent to magnetic formation
using the assembly of FIG. 4A.
[0024] FIG. 7C is a side cut-away view of a tube-fitting coupling
subsequent to metallurgical formation using the assembly of FIG.
5A.
[0025] FIG. 8 is a cross-sectional side view of a sample fluid
carrying ferrule in accordance with an embodiment of the present
invention.
[0026] FIG. 9 is a cross-sectional side view of a sample hydraulic
fluid carrying ferrule in accordance with an embodiment of the
present invention.
[0027] FIG. 10 is a cross-sectional side view of another sample
hydraulic fluid carrying ferrule in accordance with another
embodiment of the present invention.
[0028] FIG. 11 is a first sample method of magnetically forming a
fluid joint in accordance with an embodiment of the present
invention.
[0029] FIG. 12 is a second sample method of magnetically forming a
fluid joint in accordance with another embodiment of the present
invention.
[0030] FIG. 13 is a third sample method of magnetically forming a
fluid joint in accordance with still another embodiment of the
present invention.
[0031] FIG. 14 is a cross-sectional side view of another
insert/nest assembly that may be incorporated into the system of
FIG. 1 in accordance with still another embodiment of the present
invention.
DETAILED DESCRIPTION
[0032] In each of the following Figures, the same reference
numerals are used to refer to the same components. While the
present invention is described with respect to a system for
magnetically forming a fluid joint and to the joints formed
therefrom, the present invention may be adapted for various
applications, such as air, liquid, and fluid applications. The
present invention may be applied to both low-pressure applications,
i.e. less than approximately 2500 psi, and high-pressure
applications of greater than approximately 5000 psi, as well as to
applications therebetween. The present invention may be applied to
fluid applications in the aerospace, automotive, railway, and
nautical or watercraft industries, as well as to other industries
where fluid tight joints are utilized.
[0033] In the following description, various operating parameters
and components are described for one constructed embodiment. These
specific parameters and components are included as examples and are
not meant to be limiting.
[0034] Also, in the following description the term "fitting" may
refer to a ferrule, a nut, a union, or other fitting known in the
art. A fitting may be magnetically formed or magnetically welded to
or with a tubular conduit, as is described below.
[0035] Referring now to FIG. 1, a block diagrammatic view of a
magnetic forming system 10 in accordance with an embodiment of the
present invention is shown. The magnetic forming system 10 includes
an induction coil 12 that is utilized to magnetically form a fluid
joint between fluid carrying tubes and fittings, some examples of
fluid joints, fluid carrying tubes, and fittings are shown in FIGS.
2A-10.
[0036] In operation, the induction coil 12 receives current
generated from a current supply circuit 14 and generates an
electromagnetic field, which is utilized to mechanically form
and/or weld portions of a tube and a corresponding fitting to form
a fluid joint. The current supply circuit 14 may include a
capacitor bank 16 and a power source 18, as shown. A controller 20
is coupled to the capacitor bank 16, via transmission lines and
buses (not shown), and controls charge and discharge thereof via
the power source 18. The induction coil 12 may be coupled to a
concentrator 22 and to an electromagnetic forming insert 24 for
focusing electrical current within the induction coil 12. Features
of the insert 24 are described in greater detail below. The
controller 20 prior to forming a fluid joint may select from
various inserts 26, nests 28, and mandrels 30, within a storage
unit 32, that correspond to a particular tube and fitting
combination, as will become more apparent in view of the following
description. The selected insert and nest are fastened within a
fixed electromagnetic forming structure 34 prior to electromagnetic
forming of a tube and/or a fitting.
[0037] The concentrator 22 and electromagnetic forming insert 24
are used to adapt a compression coil, such as the induction coil
12, to a smaller diameter workpiece, having a smaller diameter than
the induction coil. The concentrator 22 and the insert 24
concentrate the magnetically exerted pressure to a specific
location on a tube and/or a fitting. When the capacitor bank 16 is
discharged through the induction coil 12, the induced current in
the magnetic field produces a magnetic pressure on the conductive
tube and/or fitting. The amount of discharged power produces a
sufficient amount of magnetic compressive or expansive pressure to
conform and deform the tube and/or fitting.
[0038] The magnetic forming system 10 may include an interchanging
device 36 that is coupled to the controller 20 and to the power
source 18. The inserts 26, nests 28, and mandrels 30 may be
manually selected or selected via the interchanging device 36 by
the controller 20 for a particular fluid joint. The interchanging
device 36 may be of various types and styles as known in the art
for the selection, replacement, insertion, and coupling of the
inserts 26, nests 28, and mandrels 30, as well as various tubes and
fittings within the magnetic forming system 10. The interchanging
device 36 may be in the form of an automated manufacturing system
and have rails and motors for the selecting, rotating, coupling,
inserting, sliding, and removing of inserts, nests, and mandrels
during fluid joint production. The interchanging device 36 may be
robotic in nature and have mechanical moving arms.
[0039] The controller 20 may be in the form of a control circuit
and have switching devices for the control of the power settings
utilized. The controller 20 may be microprocessor based such as a
computer having a central processing unit, memory (RAM and/or ROM),
and associated input and output buses. The controller 20 may be an
application-specific integrated circuit or may be formed of other
logic devices known in the art. The controller 20 may be a portion
of a central main control unit, a control circuit, combined into a
single integrated controller, or may be a stand-alone controller as
shown.
[0040] The inserts 26 are generally toroidally shaped and include
constraining inserts 38 and electromagnetic forming inserts 40. The
constraining inserts 38 prevent outward expansion of the fittings
and the tubes being formed. The electromagnetic forming inserts 40
are utilized to generate electromagnetic fields to cause the
deformation of a tube and/or fitting to form a fluid joint. The
electromagnetic inserts 40 may also constrain or limit outward
expansion of a tube and/or fitting.
[0041] Note that the sizes, materials, and current outputs of the
components of the induction coil 12 and of the current supply
circuit 14 are different depending upon whether electromagnetic
mechanical forming or metallurgical welding is performed. For
example, in performing metallurgical welding the size and capacity
of the capacitor bank and the size of the induction coil are
generally larger than those used to perform electromagnetic
mechanical forming, due to the larger amount of energy exerted in
metallurgical welding. An exerted energy example is provided below
with respect to the embodiment of FIGS. 2A and 2B.
[0042] The below described embodiments of FIGS. 2A-5B, are sample
embodiments that may be utilized in the electromagnetic forming of
the walls of a fitting and of a tube to form a fluid tight
joint.
[0043] Referring now to FIGS. 2A and 2B, a cross-sectional side
view of an insert/nest assembly 50 that may be incorporated into
the fixed structure 34 and a front half cross-sectional view of the
insert/nest assembly 50 are shown in accordance with an embodiment
of the present invention. The insert/nest assembly 50 is attached
to the fixed structure 34 via a fixed base 52 and a fixed
receptacle 54. The base 52 is coupled within the fixed structure 34
and the receptacle 54 is coupled within the base 52. The base 52
and the receptacle 54 may be of similar size and shape as the
induction coils and concentrators of the embodiments of FIGS.
3A-5B. A removable split constraining insert 56 is axially clamped
within the receptacle 54 and is coupled within a removable split
nest 58. The nest 58 holds a ferrule or fitting 60 and tube conduit
62 therein for magnetic forming thereof. An induction coil 64
resides within the tube 62. The induction coil 64 is used to
generate an electromagnetic field to expand and deform the end 66
of the tube 62, such that a mechanically formed or metallurgically
welded joint may be formed between the fitting 60 and the end
66.
[0044] A separation gap G.sub.1 exists between the tube 62 and the
induction coil 64 for assembly clearance. A fly distance gap
G.sub.2 resides between the fitting 60 and the tube 62, which
allows for the acceleration of the material in the end 66 to be
accelerated towards the fitting 60. In one sample embodiment the
gaps G.sub.1 and G.sub.2are approximately 0.05 inches in width.
[0045] The induction coil 64 has one or more coils 68 and may be of
various sizes, shapes, and strengths and may be formed of various
materials. For mechanical deformation of the end 66, the induction
coil 64 may generate a current pulse having approximately 2 kJ of
energy. Of course, other current pulses having other amounts of
energy may be utilized depending upon the materials utilized, the
sizes of the fittings and the tubes utilized, and other known
parameters. For metallurgical welding of the fitting 60 with the
end 66, the induction coil 64 may generate an energy pulse having
approximately between 50-100 kJ. In one metallurgical welding
embodiment of the present invention, the energy pulse is
approximately 80 kJ. The induction coil 64 may have a handle
portion 70 with a first step 72 and a second step 74, which may
abut the nest 58 and the fitting 60, respectively.
[0046] The receptacle 54 and the insert 56 may be formed of various
materials that allow for the outward constraining of the fitting 60
and the tube 62. The receptacle 54 and the insert 56 may be formed
of stainless steel and are used to prevent or limit the outward
expansion of the fitting 60 and the tube 62. The receptacle 54
includes a tapered inner surface 76 that corresponds with a tapered
outer surface 78 of the insert 56, which allow for the clamping and
proper securing of the insert 56 within the receptacle 54. Although
the insert 60 is shown as having a tapered surface 76, which is
axially clamped within the receptacle 54, the insert 60 may be
coupled to the receptacle 54 utilizing other known coupling
techniques. The axial clamping force applied to the insert 56 is
represented by arrows 80.
[0047] The nest 58 may be of various sizes, shapes, and styles, and
may be formed of various non-metallic materials. In one embodiment,
the nest 58 is formed of plastic. The nest 58 holds the fitting 60
and the tube 62 in alignment. The nest 58 also holds the induction
coil 64 in place for proper alignment with the fitting 60 and the
tube 62.
[0048] The insert 56 also includes tapered sides 82 and 84 that
correspond with an insert-angled channel 86 of the nest 58. The
tapered sides 82 and 84 converge towards a centerline 88 of the
nest 58. As the insert 56 is clamped into the receptacle 54, inward
force is exerted on the walls 90 of the nest 58, which holds the
upper half 92 and the lower half 94 of the nest 58 in place
relative to each other. The left side 87 and the right side 89 of
the nest 58 may be coupled to each other via fasteners extending
therethrough in a circular pattern or via some other technique
known in the art. The receptacle 54 and the insert 56 may be
integrally formed as a single unit.
[0049] The fitting 60 and the tube 62 may be formed of various
metallic materials, such as aluminum, stainless steel, and
titanium. The fitting 60 includes grooves 100, in a tube inlay
section 101, in which the wall 102 of the tube 62 is deformed
therein. This deformation into the grooves 100 provides a
non-sealant based fluid tight seal. Although a non-sealant based
fluid tight seal may be formed as suggested, sealants known in the
art may be utilized, for example, an O-ring or an adhesive may be
utilized between the fitting 60 and the tube 62. The tube end 66
may abut the fitting 60 at the inner step or tube-butting edge 104
of the fitting 60. The tube 62 is shown having a nut 106 for
coupling to a union. The threads 108 of the nut 106 may reside on
an internal surface 110 of the nut 106, as shown, or may reside on
an external surface, as shown in FIG. 4A.
[0050] The insert 56 and nest 58 are split to provide ease in
set-up and disassembling of the insert/nest assembly 50. The insert
56 includes an insert upper half 112 and an insert lower half 114.
The nest 58, as stated above, includes the nest upper half 92 and
the nest lower half 94. A gap G.sub.3 resides between the upper
halves 92 and 112 and the lower halves 94 and 114 for magnetic
reaction.
[0051] Referring now to FIGS. 3A and 3B, a cross-sectional side
view of a insert/nest assembly 130 that may be incorporated into
the fixed structure 34 and a front half cross-sectional view of the
insert/nest assembly 130 are shown in accordance with another
embodiment of the present invention. The insert/nest assembly 130
is coupled within a permanent or fixed concentrator 132, which in
turn is coupled within a permanent or fixed induction coil 134. The
insert/nest assembly 130 includes an electromagnetic forming insert
136 that resides within the concentrator 132. An inward
constraining mandrel 138 resides within the fitting 140 and the
tube 142.
[0052] A gap G.sub.3' resides between the upper halves 157 and 164
and the lower halves 159 and 166 for magnetic reaction. An assembly
clearance gap G.sub.4 resides between the insert 136 and the tube
end 143. A fly distance gap G.sub.5 resides between the fitting 140
and the tube 142, which allows for the material in the expanded
portion 144 to be accelerated towards the tube 142.
[0053] In operation, current within the induction coil 134 is
focused by the concentrator 132 and the insert 136 to generate an
electromagnetic field, which is imposed on the fitting 140. The
expanded portion 144 of the exterior wall 146 of the fitting 140 is
compressed and accelerated towards the tube 142. The mandrel 138
limits the inward displacement of the fitting and the tube 142.
[0054] The concentrator 132 and the insert 136 may be formed of
beryllium copper BeCu or the like. The concentrator 132 also has a
tapered inner surface 148 that corresponds with a tapered outer
surface 150 of the insert 136. The tapered surfaces 148 and 150 and
the coupling therebetween allow for the clamping and the proper
securing of the insert 136 within the concentrator 132. The tapered
surfaces 148 and 150 assure a solid contact between the
concentrator 132 and the insert 136, such that there is no arcing
therebetween and also provides for proper operation of the
associated magnetic forming system. The concentrator 132 and the
insert 136 may be integrally formed as a single unit.
[0055] Like the insert 56, the insert 136 also includes tapered
sides 152 and 154 that correspond with an insert-angled channel 156
of the nest 158. The tapered sides 152 and 154 converge towards a
centerline 160 of the nest 158. As the insert 136 is clamped into
the concentrator 132, inward force is exerted on the walls 162 of
the nest 158, which holds the upper and lower halves 164 and 166 of
the nest 158 in place relative to each other. The insert 136
includes an insert upper half 157 and an insert lower half 159.
[0056] The mandrel 138 has a handle portion 170 and an insert
portion 172 with a step 174 therebetween. The insert portion 172
may be slightly tapered, although not shown, and is inserted within
the fitting 140 and the tube 142. The outer edges 176 of the insert
portion 172, when tapered, are tapered inward towards the
centerline 160 away from the handle portion 170. The mandrel 138
may abut the nest 158 or the fitting 140 via the first step 178 or
the second step 174, respectively. The mandrel 138 may, as an
example, be formed of stainless steel and plastic.
[0057] Referring now to FIGS. 4A and 4B, a cross-sectional side
view of a insert/nest assembly 200 that may be incorporated into
the fixed structure 34 and a front half cross-sectional view of the
insert/nest assembly 200 are shown in accordance with still another
embodiment of the present invention. The configuration of the
insert/nest assembly 200 is similar to that of the insert/nest
assembly 130. However, in the example embodiment of FIGS. 4A and 4B
a tube 202 having an expanded end 204 is compressed onto a fitting
206, as opposed to a fitting being compressed onto a tube. Fitting
features are described with respect to the embodiments of FIGS.
8-10. Thus, the electromagnetic forming insert 208 has a different
shape than the insert 136 to accommodate for this difference in the
tube/fitting relationship.
[0058] An assembly clearance gap G.sub.6 resides between the tube
202 and the insert 208. A fly distance gap G.sub.7 resides between
the tube 202 and the fitting 206, respectively, which allows for
the acceleration of the material in the expanded end 204 to be
accelerated towards the fitting 206.
[0059] Note that the nut 210 on the tube 202 has threads 212 on an
exterior side 214 as opposed to an interior side, as with the nut
106. There is no correlation between the overlap relationship of
the fitting 206 and the tube 202 and the location of the threads
212. The threads 212 are shown on the exterior side 214 to
illustrate another possible embodiment and another example as to
the different internal shape of a nest. The nest 216 is shaped to
accommodate the insert 208 and the nut 210.
[0060] Referring now to FIGS. 5A and 5B, a cross-sectional side
view of an insert/nest assembly 230 that may be incorporated into
the fixed structure 34 and a front half cross-sectional view of the
insert/nest assembly 230 are shown in accordance with another
embodiment of the present invention. In operation, the insert/nest
assembly is used to metallurgically combine the tube wall portion
231 and the fitting wall portion 233 to form a tube/fitting mesh,
as shown in FIG. 7C.
[0061] The embodiment of FIGS. 5A and 5B is similar to that of
FIGS. 4A and 4B. However, the fitting 232 does not include grooves.
Although metallurgical welding may be applied to any of the
configurations of FIGS. 2A-5B, FIG. 5A and 5B illustrate that since
the walls of a fitting and of a tube are metallurgically combined,
that fittings and tubes without grooves may be utilized in the
metallurgical welding process to form fluid tight joints.
[0062] The fittings 140, 206 and 232 and the tubes 142, 202, and
234 may be formed of similar materials as the fitting 60 and the
tubes 62.
[0063] Referring now to FIG. 6, a side cut-away view of a
tube/fitting coupling 240 is shown, incorporating a tube/fitting
fluid joint 242 formed using one of the insert/nest assemblies 50
and 130. The fluid joint 242 is a non-sealant based fluid tight
seal, as well as other fluid joints herein described. The
tube/fitting coupling 240 includes a first tube 244 having a union
246 residing thereon and a second tube 248 having a nut 250. In
connecting the first tube 244 to the second tube 248 the nut 250 is
threaded onto the union 246. The tip 252 of the union 246 is
pressed into the ferrule 254 due to the coupling between the nut
250 and the ferrule 254 and the threading of the nut 250 onto the
union 246. The nut 250 includes a ferrule-chamfered surface 256
that corresponds with a middle tapered exterior surface 258 of the
ferrule 254. As the nut 250 is threaded onto the union 246 the nut
250 pulls the union 246 into the ferrule 254.
[0064] The union 246 may include grooves 260 on an interior surface
262. A first end 264 of the first tube 244 may be expanded and
formed into the grooves 260 using a magnetic forming or magnetic
welding process as described herein. The ferrule 254 resides
between the nut 250 and the union 246 and is coupled to the second
tube 248 via a magnetic forming or magnetic welding process of the
present invention, such as that described in the embodiments of
FIGS. 2A-3B.
[0065] The ferrule 254 includes a union chamfered surface 264 in
which the tapered tip 252 resides when coupled to the ferrule 254.
The ferrule 254 also includes multiple grooves 266 on an interior
side 268 for forming of the second tube 248 therein.
[0066] Referring now to FIGS. 7A and 7B, a half-side
cross-sectional view of a tube/fitting coupling 270 is shown prior
and subsequent to magnetic formation using the assembly of FIG. 4A,
along with a side cut-away view of the tube/fitting coupling 270
subsequent to magnetic formation.
[0067] The tube/fitting coupling 270 includes a first tube 292 and
a second tube 274. The second tube 274 is coupled to a fitting 272
via a fluid tight joint 276 therebetween. The fitting 272 includes
multiple grooves 278 that are located on an exterior side 280 of
the fitting 272 in a tube overlap region 282. The tube 274 has an
end portion 284 that overlaps the fitting 272. The end portion 284
is expanded prior to being slid over the overlap region 282. Fly
distance gaps G.sub.8 and G.sub.9 exist between the overlap region
282 and the end portion 284. The fly distance gaps G.sub.8 and
G.sub.9 exist between the grooves 278 and the end portion 284 and
between the end portion 284 and the ribs 286, respectively.
[0068] In FIG. 7A, the end portion 284 is shown in a first position
288, representing the end portion 284 prior to magnetic forming,
and in a second position 290, representing the end portion 284
subsequent to magnetic forming. During magnetic forming the end
portion 284 is formed into the grooves 278. The bent sections of
the end portion 284 may be referred to as electromagnetic field
formed wall deformations. Three such sections 291 are shown.
[0069] In FIG. 7B, the tube/fitting coupling 270 is shown
illustrating the union coupling between the first tube 292 and the
second tube 274. The tube/fitting coupling 270 includes the first
tube 292 and the union 294, which are similar to the first tube 244
and the union 246. The first tube 292 and the union 294 are coupled
to the second tube 274 and to the ferrule 272.
[0070] Referring now to FIG. 7C, a side cut-away view of a
tube/fitting coupling 295 subsequent to metallurgical formation.
The tube/fitting coupling 295 includes a tube/fitting mesh 296 that
is a metallurgically formed fluid circuit joint, which is in the
form of a shared wall section between a tube 297 and a ferrule 298.
The tube/fitting mesh 296 includes materials from wall portions of
the tube 297 and the ferrule 298.
[0071] Although metallurgical welding may be applied to any of the
configurations of FIGS. 2A-4B, since the walls of the fitting and
of the tube are metallurgically combined, a fitting and a tube that
do not contain any grooves may be utilized in the metallurgical
welding process to form a fluid tight joint.
[0072] The embodiments of FIGS. 2A-5B may be applied to
low-pressure fluid applications to form the tube/fitting joints of
FIGS. 6-7C. The tube/fitting joints of FIGS. 6-7C when containing
thin-walled tubes and/or fittings are capable of withstanding
internal fluid pressures of approximately equal to or less than
2500 psi and thus have a fluid pressure rating as such. An example
of a thin-walled tube is one in which the thickness of the tube
wall is approximately less than 0.1 multiplied by the average
radius of the tube.
[0073] Referring now to FIG. 8, a cross-sectional side view of a
sample fluid-carrying ferrule 300 in accordance with an embodiment
of the present invention is shown. The fluid-carrying ferrule 300
includes a wall 302 having a fluid-union coupling region 304 and a
tube overlap region 306. A tube end, not shown, may reside over the
overlap region 306 and abut the step 308 of the wall 302.
[0074] The overlap region 306 includes multiple grooves 310.
Although two grooves are shown having a particular shape and size,
any number of grooves, having various sizes and shapes may be
utilized, depending upon the application. Each groove 310 provides
an additional fluid tight transition for additional leak
prevention.
[0075] In the embodiment shown, the overlap region 306 includes a
first groove 312 and a second groove 314. The first groove 312 is
slightly wider than the second groove 314. There is approximately
equal distance between the step 308 and the first groove 312 as
between the first groove 312 and the second groove 314. The widths
W.sub.1 and W.sub.2 of the grooves 310 may be approximately equal
to the separation distances D.sub.1 and D.sub.2 between the step
308 and the grooves 310.
[0076] The ferrule 300 also includes a chamfered inner surface 316
for coupling to a union, such as unions 246 and 294. The ferrule
300 further includes, within the overlap region 306 a break edge
318, which allows for easy insertion into a tubular conduit.
[0077] Referring now to FIGS. 9 and 10, cross-sectional side views
of sample hydraulic fluid carrying ferrules 330 and 332 are shown
in accordance with an embodiment of the present invention. The
hydraulic ferrules 330 and 332 include walls 334 and 336 having
hydraulic union coupling regions 338 and 340 and tube overlap
regions 342 and 344.
[0078] The hydraulic-coupling regions 338 and 340 are different
than that of the air-coupling region 304 to accommodate for the
different application. The hydraulic-coupling regions 338 and 340
may include a standard wall section 350, steps 352, and arched
sections 354. The steps 352 also include radius edges 359 that are
associated with an end of a tubular conduit (not shown).
[0079] The tube overlap regions 342 and 344 are similar to the tube
overlap region 306. The tube overlap regions 342 and 344 may or may
not have a break edge.
[0080] In the methods of FIGS. 11-13, the material compositions of
the tubes and the fittings utilized can affect the ability of the
tubes and or the fittings to be deformed. As an example, when it is
desired for a fitting to be deformed as opposed to a tube, the
material composition of the fitting may be adjusted and/or have
less tensile strength than that of the tube to allow for such
deformation. The thickness of the tube and fitting walls may also
be adjusted to provide various degrees of tensile strength. In
addition, the electromagnetic current pulses utilized may also be
adjusted to provide the desired deformation in the tube and the
fitting.
[0081] Referring now to FIG. 11, a first sample method of
magnetically forming a fluid joint in accordance with an embodiment
of the present invention is shown.
[0082] In step 502, the current tube is inserted into the current
fitting. The tube may be inserted into the fitting manually or
through use of the interchanging device 36. In step 506, the
induction coil is inserted into the current tube.
[0083] In step 508, inserting the current tube, the current
fitting, and the induction coil into a nest. The current tube, the
current fitting, and the induction coil are placed on a first half
of a selected nest, such as the nest half 92. The nest may be
selected from the nests 28. The second half of the nest, such as
the nest half 94, is placed over the first half covering the
fitting, the tube, and the induction coil.
[0084] In step 510, an insert, such as one of the constraining
inserts 38 or the constraining insert 56, is attached and/or
inserted into the nest.
[0085] In step 512, the nest and the insert are clamped into a
fixed receptacle, such as the receptacle 54. The insert is press
fitted into the receptacle using techniques known in the art.
[0086] In step 514, a controller, such as the controller 20, via a
capacitor bank and the induction coil generates an electromagnetic
field. An electromagnetic current is discharged from the capacitor
bank into the induction coil in response to a current pulse signal
generated from the controller 20.
[0087] In step 516, the induction coil in generating the
electromagnetic field imposes the electromagnetic field upon the
tube. The electromagnetic field accelerates the end of the tube
toward the fitting, thereby expanding the end of the tube within
the fitting and deforming the end into the grooves, such as the
grooves 100, of the fitting. The fly distance gap, such as the gap
G.sub.2, between the tube and the fitting allow for the
acceleration of the tube end. The expansion and deformation of the
tube end against the fitting forms a pressure tight fluid
joint.
[0088] Electrical current from the capacitor bank is passed through
the induction coil, which generates an intense electromagnetic
field and creates high magnitude eddy currents in the tube end. The
opposing magnetic fields that are directly generated by the
induction coil and that are generated by the eddy currents
accelerate the tube end towards the fitting. When electromagnetic
mechanical forming is performed the tube end is deformed into the
grooves of the fitting. When electromagnetic welding is performed
the tube end is metallurgically welded with the fitting.
[0089] A high current pulse of short duration, approximately
between about 10 and 100 microseconds, is introduced to the coils
of the induction coil, which generates the electromagnetic field to
instantaneously deform the tube radially outward towards the
insert, resulting in the crimping or metallurgical welding of the
tube to the fitting to form the fluid joint. The pulse is strong
enough to induce magnetic forces above the yield strength of the
material in the tube.
[0090] In step 518, the insert and the receptacle, during
electromagnetic forming of the tube, constrain or limit the
expansion of the tube and the fitting. Steps 514-518 are
substantially performed simultaneously.
[0091] In step 520, upon completion of steps 514-518 the current
nest is removed from the receptacle containing the fluid joint. In
step 522, the fluid joint is removed from the current nest. The
first half and the second half of the current nest are separated to
allow for the removal of the fluid joint.
[0092] In step 524, it is determined whether the current setup and
configuration of the current tube and the current fitting is to be
reused or replaced. The controller may determine whether to form
another tube/fitting coupling using the current insert and nest
arrangement or to select a replacement insert and nest. The
replacement insert and nest may have different internal dimensions
as compared with the current insert and nest and may be selected
from the constraining inserts 38 and the nests 28. The different
internal dimensions may correspond to a tube/fitting coupling of
different size, to a tube/fitting coupling having a different
tube/fitting configuration, to a tube/fitting coupling formed using
a different electromagnetic forming or electromagnetic welding
technique, or to other known tube/fitting related differences known
in the art. Steps 520-524 may be performed via the interchanging
mechanism 36. Upon selection of a second or replacement tube, a
second or replacement fitting, a replacement insert, and a
replacement nest, the controller 20 returns to step 502.
[0093] Referring now to FIG. 12, a second sample method of
magnetically forming a fluid joint in accordance with another
embodiment of the present invention is shown.
[0094] In step 550, a tube insert section or portion of a current
fitting, such as the portion 144, may be expanded also via an
end-forming device or originally machined with a tapered shape. In
step 552, a tube end of a current tube, such as the tube end 143,
is inserted into the fitting. In step 554, a temporary mandrel is
selected, such as the mandrel 176, and is inserted into the tube
and the fitting. The mandrel is inserted into the tube to prevent
excessive tube-wall collapse.
[0095] In step 556, the tube, the fitting, and the mandrel are
inserted into a current nest, such as the nest 166. The tube, the
fitting, and the mandrel are placed on a first half of the nest.
The second half of the nest is placed over the first half covering
the fitting, the tube, and the mandrel. In step 558, an insert,
such as one of the electromagnetic forming inserts 40 or the
electromagnetic forming insert 136, is attached and/or inserted
into the nest.
[0096] In step 560, the nest and the insert are clamped into a
fixed concentrator, such as the concentrator 132. The insert is
press fitted into the concentrator using techniques known in the
art.
[0097] In step 562, the controller 20, via a capacitor bank and an
induction coil, such as the induction coil 134, generates a first
stage electromagnetic current that is passed into the concentrator
via coupling between the concentrator and the induction coil. An
electromagnetic current is discharged from the capacitor bank into
the induction coil, which is then passed into the concentrator. In
step 564, a field concentrator focuses the first stage
electromagnetic current to form a second stage electromagnetic
current, which is passed into the insert via the coupling between
the concentrator and the insert. In step 566, the insert focuses
the second stage electromagnetic current and forms an
electromagnetic field.
[0098] In step 568, the electromagnetic field is imposed upon the
exterior of the fitting and accelerates and compresses the tube
insert section onto the tube. In accelerating and compressing the
fitting onto the tube, the tube end is deformed into the grooves of
the fitting. The fly distance gap, between the insert and the tube,
such as the gap G.sub.5, allows for the acceleration of the tube
insert section of the fitting. The compression of the fitting and
the deformation of the tube form a fluid joint. In step 570, the
mandrel constrains or limits the compression of the fitting and the
tube during electromagnetic formation. Steps 562-570 are
substantially performed simultaneously.
[0099] In step 572, upon completion of steps 562-570 the current
nest is removed from the concentrator containing the fluid joint.
In step 574, the fluid joint is removed from the current nest. The
first half and the second half of the current nest are separated to
allow for the removal of the fluid joint.
[0100] In step 576, it is determined whether the current setup and
configuration of the current tube and the current fitting is to be
reused or replaced, similar to step 524 above. The controller may
determine whether to form another tube/fitting coupling using the
current insert and nest arrangement or to select a replacement
insert and nest. Steps 572-576 may be performed via the
interchanging mechanism. Upon selection of a second or replacement
tube, a second or replacement fitting, a replacement insert, and a
replacement nest, the controller returns to step 550.
[0101] Referring now to FIG. 13, a third sample method of
magnetically forming a fluid joint in accordance with still another
embodiment of the present invention is shown.
[0102] In step 600, a current tube end, such as the tube end 204,
is expanded using an end-forming device. In step 602, a current
fitting, such as the fitting 206 or the fitting 272, is inserted
into the tube end. In step 604, a mandrel, such as the mandrel 138,
is inserted into the tube and the fitting.
[0103] In step 606, the tube, the fitting, and the mandrel are
inserted into a current nest, such as the nest 216. The tube, the
fitting, and the mandrel are placed on a first half of the nest.
The second half of the nest is placed over the first half covering
the fitting, the tube, and the mandrel.
[0104] In step 608, an insert, such as one of the electromagnetic
forming inserts 40 or the electromagnetic forming insert 208, is
attached and/or inserted into the nest. In step 610, the nest and
the insert are clamped into a fixed concentrator, such as the
concentrator 132. The insert is press fitted into the concentrator
using techniques known in the art.
[0105] In step 612, the controller 20, via the capacitor bank and
the induction coil, such as the induction coil 134, generates a
first stage electromagnetic current that is passed into the
concentrator via coupling between the concentrator and the
induction coil. An electromagnetic current is discharged from the
capacitor bank into the induction coil, which is then passed into
the concentrator. In step 614, the field concentrator focuses the
first stage electromagnetic current to form a second stage
electromagnetic current, which is passed into the insert via the
coupling between the concentrator and the insert. In step 616, the
insert focuses the second stage electromagnetic current and forms
an electromagnetic field.
[0106] In step 618, the electromagnetic field is imposed upon the
exterior of the tube and accelerates and compresses the tube end
onto the fitting, similar to step 568 above. In accelerating and
compressing the tube onto the fitting, the tube end is deformed
into the grooves of the fitting. The fly distance gap between the
insert and the tube, such as the gap G.sub.7, allows for the
acceleration of the tube end. The compression and deformation of
the tube end forms a fluid joint. In step 620, the mandrel
constrains or limits the compression of the fitting and the tube
during electromagnetic formation. Steps 612-620 are substantially
performed simultaneously.
[0107] In step 622, upon completion of steps 612-620 the current
nest is removed from the concentrator containing the fluid joint.
In step 624, the fluid joint is removed from the current nest. The
first half and the second half of the current nest are separated to
allow for the removal of the fluid joint.
[0108] In step 626, it is determined whether the current setup and
configuration of the current tube and the current fitting is to be
reused or replaced, similar to steps 524 and 576 above. The
controller may determine whether to form another tube/fitting
coupling using the current insert and nest arrangement or to select
a replacement insert and nest. Steps 612-626 may be performed via
the interchanging mechanism. Upon selection of a second or
replacement tube, a second or replacement fitting, a replacement
insert, and a replacement nest, the controller returns to step
600.
[0109] Note that the above methods may be performed without the use
of lubrication, which minimizes steps involved and can eliminate
the need for cleaning of the fittings, tubes, and fluid tight
joints.
[0110] The above-described steps in the methods of FIGS. 11-13 are
meant to be illustrative examples; the steps may be performed
sequentially, synchronously, simultaneously, or in a different
order depending upon the application.
[0111] Referring now to FIG. 14, a cross-sectional side view of
another insert/nest assembly that may be incorporated into the
system of FIG. 1 in accordance with still another embodiment of the
present invention is shown. The insert/nest assembly 700 utilizes a
field shaper 702 as opposed to a concentrator and an insert, as
described above. The insert/nest assembly includes a first half
(shown) as well as a second half (not shown), which is a mirror
image of the first half. The field shaper 702 is coupled to an
induction coil 704. An insulation layer 703 may reside between the
field shaper 702 and the induction coil 704. The induction coil 704
generates an electromagnetic field, which is imposed on the tube
706 via the field shaper 702. The electromagnetic field accelerates
the end 708 of the tube 706 toward the fitting 710, thereby
compressing the end 708 within the grooves 712 of the fitting
710.
[0112] The field shaper 702 may be formed of materials similar to
that of the field concentrators and inserts described above. The
cross-section of the field shaper 702 is "I"-shaped. The field
shaper includes an outer ring 714 and a main center disc 716 that
extends inward toward a tube/fitting forming region 718. The center
disc 716 has a semi-circular opening 720 in the tube/fitting
forming region 718. The field shaper 702 resides within a nest 721,
which has internal dimensions and geometry that correspond to that
of the field shaper 702 such that the field shaper 702 is held
fixed in place during electromagnetic forming. The nest 721 may be
formed of the nest materials stated above, such as plastic.
[0113] A mandrel 722 resides within the nest 721 and includes a
stem 724, which is inserted into the tube 706 and the fitting 710
through the tube/fitting forming region 718. The stem 724 is
coupled to a handle 726, which resides in a recessed portion 728 of
the nest 721. In one example embodiment, the stem 724 is formed of
stainless steel and the handle 726 is formed of plastic.
[0114] The present invention provides fluid tight leak joints with
reduced scrap rate. Further, because the insert/nest assemblies are
quickly and easily inserted and removed from a fixed structure, a
large quantity of tubular joints may be quickly formed. The above
stated reduces costs associated with manufacturing down times.
[0115] The present invention reduces manufacturing processing steps
as compared to conventional welding and roller swaging or
elastomeric processes. The present invention also reduces
inspection process steps, cost of production, and provides a highly
reproducible manufacturing process to maintain consistent
quality.
[0116] While the invention has been described in connection with
one or more embodiments, it is to be understood that the specific
mechanisms and techniques which have been described are merely
illustrative of the principles of the invention, numerous
modifications may be made to the methods and apparatus described
without departing from the spirit and scope of the invention as
defined by the appended claims.
* * * * *