U.S. patent application number 10/401716 was filed with the patent office on 2004-09-30 for method for resistance welding a tube to a member.
Invention is credited to Ananthanarayanan, Venkatasubramanian, Ramachandra, Dharmendra M..
Application Number | 20040188389 10/401716 |
Document ID | / |
Family ID | 32927336 |
Filed Date | 2004-09-30 |
United States Patent
Application |
20040188389 |
Kind Code |
A1 |
Ananthanarayanan,
Venkatasubramanian ; et al. |
September 30, 2004 |
METHOD FOR RESISTANCE WELDING A TUBE TO A MEMBER
Abstract
A method for resistance welding a tube to a member. A tube is
obtained having an axially-extending first portion and having a
tube form which extends transversely from the first portion. The
tube form has at least one axial projection. The tube and the
member are positioned with the at-least-one axial projection in
contact with the member. A resistance welding current path is
created through the member and the tube including the at-least-one
axial projection creating a weld zone which includes at least some
of the at-least-one axial projection and at least some of the
member.
Inventors: |
Ananthanarayanan,
Venkatasubramanian; (Dayton, OH) ; Ramachandra,
Dharmendra M.; (Centerville, OH) |
Correspondence
Address: |
Scott A. McBain
Delphi Technologies, Inc.
Legal Staff - Mail Code: 480-410-202
P.O. Box 5052
Troy
MI
48007
US
|
Family ID: |
32927336 |
Appl. No.: |
10/401716 |
Filed: |
March 28, 2003 |
Current U.S.
Class: |
219/59.1 ;
219/117.1 |
Current CPC
Class: |
B23K 11/002 20130101;
B23K 11/14 20130101; B23K 33/006 20130101 |
Class at
Publication: |
219/059.1 ;
219/117.1 |
International
Class: |
B23K 011/00 |
Claims
1. A method for resistance welding a tube to a member comprising
the steps of: a) obtaining a tube having an axially-extending first
portion and having a tube form which extends transversely from the
first portion, wherein the tube form includes at least one axial
projection; b) obtaining a member; c) after steps a) and b),
disposing the tube and the member with the at-least-one axial
projection contacting the member; and d) after step c), creating a
resistance welding current path through the member and the tube
including the at-least-one axial projection creating a weld zone
which includes at least some of the at-least-one axial projection
and at least some of the member.
2. The method of claim 1, wherein the member is a tubular
member.
3. The method of claim 1, wherein the member is a non-tubular
member.
4. The method of claim 1, wherein the tube is a substantially
circular tube.
5. The method of claim 1, wherein the tube form is disposed
proximate an end of the tube.
6. The method of claim 1, wherein the tube form is a flange.
7. The method of claim 6, wherein the flange is an annular
flange.
8. The method of claim 7, wherein the flange is an
outwardly-extending annular flange.
9. The method of claim 1, wherein the tube form is a fold.
10. The method of claim 9, wherein the fold is an annular fold.
11. The method of claim 10, wherein the fold is an
outwardly-extending annular fold.
12. The method of claim 1, wherein the tube form is a monolithic
portion of the tube, wherein the at-least-one axial projection is a
monolithic portion of the tube form, and wherein the at-least-one
axial projection was created during the creation of the tube
form.
13. The method of claim 1, wherein the tube form is an annular tube
form, and wherein the at-least-one axial projection is a single
annular axial projection.
14. The method of claim 1, wherein the at-least-one axial
projection includes a plurality of spaced-apart axial
projections.
15. The method of claim 1, wherein step d) is performed without
relatively axially moving the at-least-one axial projection
deformingly against the member.
16. The method of claim 1, wherein the weld zone created by step d)
is a leak-tight annular weld zone.
17. A method for resistance welding a tube to a member comprising
the steps of: a) obtaining a tube having an axially-extending first
portion and having a tube form which extends transversely from the
first portion, wherein the tube form includes at least one axial
projection; b) obtaining a member; c) after steps a) and b),
disposing the tube and the member with the at-least-one axial
projection contacting the member; and d) after step c), creating a
resistance welding current path through the member and the tube
including the at-least-one axial projection and relatively axially
moving the at-least-one axial projection deformingly against the
member creating a weld zone which includes at least some of the
at-least-one axial projection and at least some of the member.
18. The method of claim 17, wherein the tube form is a flange.
19. The method of claim 17, wherein the tube form is a fold.
Description
TECHNICAL FIELD
[0001] The present invention relates generally to welding, and more
particularly to a method for resistance welding a tube to a
member.
BACKGROUND OF THE INVENTION
[0002] Resistance welding (also known as electric-resistance
welding) is a known metallurgical process used to weld a
right-angle end flange of a tube to a surface projection of a plate
wherein metal is heated by its own resistance to a semi-fused
(i.e., soft) or fused (i.e., molten) state by the passage of very
heavy electric currents for very short lengths of time and then
welded. In one known variation, the plate is stamped creating
depressions on the top surface and creating surface projections on
the bottom surface so that during the resistance welding, the
projections soften and/or melt creating a weld nugget which joins
together the plate to the tube flange.
[0003] Conventional methods for welding a tube to another tube or
for welding a tube to a plate include gas metal arc welding. Gas
metal arc welding uses a consumable metal wire as one electrode and
the parts as another electrode, and moves the consumable metal wire
(or the parts) to draw an arc and weld the parts together. The
welding is accompanied by a gas (such as a mixture of argon and
carbon dioxide) to prevent oxidation and stabilize the arc. Such
gas metal arc welding is well known. In a conventional gas metal
arc welding technique, solid metal wire or metal core wire (i.e.,
an annular-solid wire whose core is filled with metal powder such
as a mixture of metal, alloy and/or oxide powders) is used with the
wire at a positive electrical welding potential and with the parts
electrically grounded. The welding arc creates a molten weld puddle
which results in the welding together of the parts. A ceramic
ferrule is used to contain the weld puddle when needed. Gas metal
arc welding requires expensive welding equipment, the molten weld
puddle tends to flow away from the joint area (depending on the
joint position with respect to gravity) resulting in welds of
inconsistent quality, and the process requires a long cycle time
between welds.
[0004] Conventional methods for attaching parts together also
include friction welding. To join two tubes together end to end,
one of the tubes is rotated about its longitudinal axis, and the
tube ends are pressed together, wherein friction causes heating of
the ends creating the weld. To join a tube to a plate, the tube is
rotated about its longitudinal axis, and the tube end and the plate
are pressed together, wherein friction causes heating creating the
weld. Friction welding requires expensive welding equipment, and
the process requires a long cycle time between welds. Friction
welding is not easily applicable to thin-walled tubes because they
do not retain their shapes well under heat and pressure. It is
noted that laser and electron-beam welding for the above joints
also need expensive equipment and expensive joint preparation.
[0005] What is needed is a less expensive method for
metallurgically joining a tube to a member.
SUMMARY OF THE INVENTION
[0006] A first method of the invention is for resistance welding a
tube to a member and includes steps a) through d). Step a) includes
obtaining a tube having an axially-extending first portion and
having a tube form which extends transversely from the first
portion, wherein the tube form includes at least one axial
projection. Step b) includes obtaining a member. Step c) includes,
after steps a) and b), positioning the tube and the member with the
at-least-one axial projection contacting the member. Step d)
includes, after step c), creating a resistance welding current path
through the member and the tube including the at-least-one axial
projection creating a weld zone which includes at least some of the
at-least-one axial projection and at least some of the member.
[0007] A second method of the invention is for resistance welding a
tube to a member and includes steps a) through d). Step a) includes
obtaining a tube having an axially-extending first portion and
having a tube form which extends transversely from the first
portion, wherein the tube form includes at least one axial
projection. Step b) includes obtaining a member. Step c) includes,
after steps a) and b), positioning the tube and the member with the
at-least-one axial projection contacting the member. Step d)
includes, after step c), creating a resistance welding current path
through the member and the tube including the at-least-one axial
projection and relatively axially moving the at-least-one axial
projection deformingly against the member creating a weld zone
which includes at least some of the at-least-one axial projection
and at least some of the member.
[0008] Several benefits and advantages are derived from one or more
of the methods of the invention. The tube form allows resistance
welding of a tube to a member to be commercially feasible, as can
be appreciated by those skilled in the art. The at-least-one axial
projection enables the welding of thick-thin part combinations and
allows a smaller welding current to be used since all of the
welding current creating the weld zone flows only through the
projection(s) and not through a larger area. Resistance welding is
less expensive than gas metal arc welding or friction welding.
Resistance welding also has a shorter cycle time between welds than
gas metal arc welding or friction welding.
SUMMARY OF THE DRAWINGS
[0009] FIG. 1 is a block diagram of a first method of the invention
for resistance welding a tube to a member;
[0010] FIG. 2 is a schematic, side cross-sectional view of a first
embodiment of a tube and a member (which is another tube) used in a
first example of the first method, showing the tubes just before
welding;
[0011] FIG. 3 is a view, as in FIG. 2, but showing the two tubes
after welding and with the welding electrodes removed;
[0012] FIG. 4 is a view along lines 4-4 in FIG. 2 showing a first
shape of the at-least-one axial projection with the welding
electrodes removed;
[0013] FIG. 5 is a view, as in FIG. 4, but showing a second shape
of the at-least-one axial projection;
[0014] FIG. 6 is a view, as in FIG. 4, but showing a third shape of
the at-least-one axial projection;
[0015] FIG. 7, is a view, as in FIG. 2, but showing a second
embodiment of a tube and a member (which is a plate) used in a
second example of the first method, showing the tube and the plate
just before welding.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] A first method of the invention is for resistance welding a
tube 10 to a member 12 and is shown in block diagram form in FIG. 1
with a first embodiment of the tube 10 and the member 12 shown in
FIGS. 2 and 3. The first method includes steps a) through d). Step
a) is labeled as "Obtain Tube Having A Tube Form" in block 14 of
FIG. 1. Step a) includes obtaining a tube 10 having an
axially-extending first portion 16 and having a tube form 18 which
extends transversely from the first portion 16, wherein the tube
form 18 includes at least one axial projection 20. Step b) is
labeled as "Obtain Member" in block 22 of FIG. 1. Step b) includes
obtaining a member 12. Step c) is labeled as "Dispose Tube and
Member" in block 24 of FIG. 1. Step c) includes, after steps a) and
b), disposing the tube 10 and the member 12 with the at-least-one
axial projection 20 contacting the member 12. Step d) is labeled as
"Create Weld Zone" in block 26 of FIG. 1. Step d) includes, after
step c), creating a resistance welding current path through the
member 12 and the tube 10 including the at-least-one axial
projection 20 creating a weld zone 28 which includes at least some
of the at-least-one axial projection 20 and at least some of the
member 12.
[0017] In one example of the first method, the member 12 is a
tubular member as shown in FIGS. 2 and 3. In one modification, the
weld zone 28 extends the width of the tube form 18 as can be seen
in FIG. 3. In another modification, not shown, the weld zone
extends the width of the axial projection 20. In one variation, not
shown, a portion of the tube above the tube form extends inside the
tubular member. In a different example, the member is a non-tubular
member. In one variation, the member is a plate (without a hole or
with a hole in which the tube is partially disposed). In another
variation, the member is a thicker solid. Other modifications,
variations, and the choice of weldable materials making up the tube
and the member, are left to the artisan.
[0018] In one construction using the first method, the tube 10 is a
substantially circular tube. In one variation, the tube 10 is a
completely straight tube. In another variation, the tube is a bent
or otherwise non-straight tube. In one modification, the tube is a
long tube. In another modification, the tube is a short tubular
connector. It is noted that a tube axially extends along its
centerline and that the length of a tube is the distance along its
centerline whether the centerline is straight or not. Other
constructions, variations, and modifications of the tube are left
to the artisan.
[0019] In one embodiment using the first method, the tube form 18
is disposed proximate an end of the tube 10 as shown in FIG. 2. The
term "proximate" includes "at". In a different embodiment, the tube
form is disposed elsewhere on the tube than proximate an end of the
tube. In one variation of this different embodiment, the first
method resistance welds a tube to a plate wherein the plate has a
through hole and wherein the tube extends both above and below the
plate. Other embodiments and variations are left to the
artisan.
[0020] In one enablement of the first method, the tube form 18 is a
fold 30 as shown in FIG. 2. A "fold" is a fold of the tube wall of
a portion of the tube. The fold may or may not include
axially-spaced-apart first and second fold portions. In one
variation, the fold is an annular fold. In one modification, the
fold is an outwardly-extending annular fold. In a different
enablement, the tube form 18 is a flange. For purposes of
describing any of the methods, a flange is a tube form which does
not include a fold. In one variation, the flange is an annular
flange. In one modification, the flange is an outwardly-extending
annular flange. Other annular and non-annular tube forms, including
inwardly-extending (or both inwardly and outwardly-extending) tube
forms, are left to the artisan.
[0021] In one enablement of the first method, the tube form 18 is a
monolithic portion of the tube 10 and the at-least-one axial
projection 20 is a monolithic portion of the tube form 18, wherein
the at-least-one axial projection 20 was created during the
creation of the tube form 18. In one technique, conventional tube
forming methods are used to create the tube form 18 such as by
surrounding the tube 10 with a die having a tube-form-shaped
recess, supporting the inside of the tube 10 with a solid cylinder,
and pushing against the ends of the tube 10 to force a portion of
the tube 10 into the recess to create the tube form 18 including
the at-least-one axial projection 20. In another technique, the
tube 10 is created by pouring molten metal into a tube mold which
is shaped to create the tube form 18 including the at-least-one
axial projection 20. Other enablements and techniques are left to
the artisan.
[0022] In one axial-projection design using the first method, the
tube form 18 is an annular tube form, and the at-least-one axial
projection 20 is a single annular axial projection 32 shown in the
example of FIG. 4. In alternate designs, the at-least-one axial
projection 18 includes a plurality of spaced-apart axial
projections 34 and 36 shown in the examples of FIGS. 5 and 6. Other
designs of the at-least-one axial projection 20 are left to the
artisan.
[0023] FIG. 2 shows one electrode choice which can be used in a
conventional resistance welding machine to perform the first
method. In this choice, first and second electrodes 38 and 40 are
used. The first electrode 38 is an annular (e.g., a one or two or
more piece annular) electrode disposed axially against the tube
form 18 on a surface of the tube form 18 opposite the at-least-one
axial projection 20. The second electrode 40 is an annular
electrode disposed as shown in FIG. 2.
[0024] In one technique using the first method, step d) is
performed without relatively axially moving the at-least-one axial
projection 20 deformingly against the member 12. In another
technique step d) includes relatively axially moving the
at-least-one axial projection 20 deformingly against the member 12.
It is noted that the resistance welding of step d) is with or
without the application of deforming pressure when the metal to be
welded is melted and that the resistance welding of step d) is with
the application of deforming pressure when the metal to be welded
is only softened. Even when not applying deforming pressure, the
tube 10 and the member 12 typically would be moved toward each
other to maintain the resistance welding current path during step
d).
[0025] In one option using the first method, the weld zone 28
created by step d) is a leak-tight annular weld zone. It is noted
that a single non-annular axial projection or a plurality of widely
spaced apart axial projections is unlikely to result in a
leak-tight annular weld zone. A non-leak-tight weld zone is
satisfactory for particular welding applications as can be
appreciated by the artisan.
[0026] A second method of the invention is for resistance welding a
tube 10 to a member 12 and includes steps a) through d). Step a)
includes obtaining a tube 10 having an axially-extending first
portion 16 and having a tube form 18 which extends transversely
from the first portion 16, wherein the tube form 18 includes at
least one axial projection 20. Step b) includes obtaining a member
12. Step c) includes, after steps a) and b), disposing the tube 10
and the member 12 with the at-least-one axial projection 20
contacting the member 12. Step d) includes, after step c), creating
a resistance welding current path through the member 12 and the
tube 10 including the at-least-one axial projection 20 and
relatively axially moving the at-least-one axial projection 20
deformingly against the member 12 creating a weld zone 28 which
includes at least some of the at-least-one axial projection 20 and
at least some of the member 12. By "relatively moving" a first
piece against a second piece is meant moving the first piece
against the second piece or moving the second piece against the
first piece or moving both pieces against each other.
[0027] In one procedure involving the second method, the first and
second electrodes 38 and 40 are relatively axially moved towards
each other during step d) along lines of movement indicated by
arrows 42 in FIG. 2.
[0028] In one enablement of the first method, the tube form 18 is a
fold 30 as shown in FIG. 2. In one variation, the fold 30 includes
axially-spaced-apart first and second fold portions 44 and 46. In a
different enablement, the tube form 18 is a flange. Other tube
forms are left to the artisan. It is noted that the optional
examples, variations, modifications, etc. of the first method are
equally applicable to the second method.
[0029] FIG. 7 shows a second embodiment of a tube 48 and a member
(which is a plate 50) used in a second example of the first and/or
second methods, showing the tube 48 and the plate 50 just before
welding. In this embodiment, the tube form 54 is a flange 60. In
one technique using this embodiment, a first electrode 62 and an
annular second electrode 64 are employed as shown in FIG. 7. It is
noted that the optional examples, etc of the first method, and the
deformation resistance welding step d) of the second method are
equally applicable to this embodiment. It is also noted that
projections may be employed on both the tube and the member in any
of the methods and embodiments.
[0030] Several benefits and advantages are derived from one or more
of the methods of the invention. The tube form allows resistance
welding of a tube to a member to be commercially feasible, as can
be appreciated by those skilled in the art. The at least one axial
projection enables the welding of thick-thin part combinations and
allows a smaller welding current to be used since all of the
welding current creating the weld zone flows only through the
projection(s) and not through a larger area. Resistance welding is
less expensive than gas metal arc welding or friction welding.
Resistance welding also has a shorter cycle time between welds than
gas metal arc welding or friction welding.
[0031] The foregoing description of a several methods of the
invention has been presented for purposes of illustration. It is
not intended to be exhaustive or to limit the invention to the
precise procedures or precise forms disclosed, and obviously many
modifications and variations are possible in light of the above
teaching. It is intended that the scope of the invention be defined
by the claims appended hereto.
* * * * *