U.S. patent application number 15/159876 was filed with the patent office on 2017-11-23 for method and apparatus to form a workpiece employing vibration welding.
This patent application is currently assigned to GM GLOBAL TECHNOLOGY OPERATIONS LLC. The applicant listed for this patent is GM GLOBAL TECHNOLOGY OPERATIONS LLC. Invention is credited to Michael P. Balogh, Wayne W. Cai, Nicholas W. Pinto, Teresa J. Rinker.
Application Number | 20170334016 15/159876 |
Document ID | / |
Family ID | 60255447 |
Filed Date | 2017-11-23 |
United States Patent
Application |
20170334016 |
Kind Code |
A1 |
Rinker; Teresa J. ; et
al. |
November 23, 2017 |
METHOD AND APPARATUS TO FORM A WORKPIECE EMPLOYING VIBRATION
WELDING
Abstract
A workpiece is described, and includes a substrate, a cable, and
a cover piece. A portion of the cable is joined to the substrate
employing a vibration welding tool, and the cover piece is
interposed between the portion of the cable and the vibration
welding tool during the joining.
Inventors: |
Rinker; Teresa J.; (Royal
Oak, MI) ; Cai; Wayne W.; (Troy, MI) ; Balogh;
Michael P.; (Novi, MI) ; Pinto; Nicholas W.;
(Shelby Township, MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GM GLOBAL TECHNOLOGY OPERATIONS LLC |
Detroit |
MI |
US |
|
|
Assignee: |
GM GLOBAL TECHNOLOGY OPERATIONS
LLC
Detroit
MI
|
Family ID: |
60255447 |
Appl. No.: |
15/159876 |
Filed: |
May 20, 2016 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B23K 2103/22 20180801;
B23K 20/2275 20130101; B23K 20/002 20130101; B23K 20/22 20130101;
B23K 2103/18 20180801; H01B 1/02 20130101; B23K 20/10 20130101;
B23K 20/227 20130101; B23K 20/004 20130101; B23K 2103/20
20180801 |
International
Class: |
B23K 20/10 20060101
B23K020/10; B23K 20/227 20060101 B23K020/227; H01B 1/02 20060101
H01B001/02 |
Claims
1. A workpiece, comprising: a substrate, a cable, and a cover
piece; wherein a portion of the cable is joined to the substrate by
a vibration welding tool; and wherein the cover piece is interposed
between the portion of the cable and the vibration welding tool
during the joining.
2. The workpiece of claim 1, wherein the cable comprises a single
strand formed from a high tensile strength steel.
3. The workpiece of claim 1, wherein the cable comprises a single
strand formed from a shape-memory alloy.
4. The workpiece of claim 1, wherein the cable comprises multiple
strands, wherein each strand is formed from a shape-memory
alloy.
5. The workpiece of claim 1, wherein the substrate and the cover
piece are fabricated from aluminum.
6. The workpiece of claim 1, wherein the substrate and the cover
piece are fabricated from copper.
7. The workpiece of claim 1, wherein the substrate is fabricated
from a thermoplastic polymer.
8. The workpiece of claim 1, wherein the cover piece comprises a
sheet element.
9. The workpiece of claim 1, wherein the cover piece comprises a
tubular sheath having a hollow portion, and wherein the portion of
the cable is inserted into the hollow portion of the tubular
sheath.
10. The workpiece of claim 1, wherein the substrate includes a
channel on surface thereof, and wherein the portion of the cable in
the channel is inserted into the channel.
11. The workpiece of claim 1, wherein the portion of the cable
joined to the substrate includes a hook portion.
12. The workpiece of claim 1, wherein the portion of the cable is
joined to the substrate in a lap arrangement.
13. A workpiece, comprising: an end portion of a first cable, an
end portion of a second cable, and a cover piece, wherein the cover
piece is employed to join the end portion of the first cable and
the end portion of the second cable; wherein a vibration welding
tool is employed to join the end portion of the first cable and the
end portion of the second cable with the cover piece; and wherein
the cover piece is interposed between the vibration welding tool
and the end portions of the first and second cables during the
joining.
14. The workpiece of claim 13, wherein the first cable and the
second cable each comprise a single strand formed from a high
tensile strength steel.
15. The workpiece of claim 13, wherein the first cable and the
second cable each comprise a single strand formed from steel having
a high Young's modulus.
16. The workpiece of claim 13, wherein the first cable and the
second cable each comprise a single strand formed from a
shape-memory alloy.
17. The workpiece of claim 13, wherein the cover piece comprises a
tubular sheath is fabricated from aluminum.
18. The workpiece of claim 13, wherein the cover piece comprises a
thin, flexible foil element that is wrapped around the end portions
of the first and second cable elements multiple times.
19. A method for joining a shape-memory alloy (SMA) cable to a
substrate employing a vibration welding system, the method
comprising, positioning a portion of the cable onto a surface of
the substrate; interposing an aluminum cover piece overtop of the
portion of the cable; placing the substrate, the portion of the
cable and the cover piece onto an anvil of the vibration welding
system such that the cover piece is interposed between the cable
and a sonotrode of the vibration welding system; and applying, via
the sonotrode of the vibration welding system, vibration energy
onto the cover piece, the portion of the cable and the substrate;
wherein applying the vibration energy mechanically joins the
substrate, the cable and the cover piece.
20. The method of claim 19, further comprising: forming a channel
on the surface of the substrate; and positioning the portion of the
cable in the channel formed on the surface of the substrate.
Description
TECHNICAL FIELD
[0001] The present disclosure relates to vibration welding systems,
and workpieces that are joined employing vibration welding
systems.
BACKGROUND
[0002] In a vibration welding process, adjacent surfaces of a
clamped workpiece are joined together by the controlled application
of vibration energy to the workpiece. Transmission of vibration
energy creates surface friction and heat along interfacing surfaces
of the workpiece. The heat softens the materials of the interfacing
surfaces which ultimately bonds the surfaces together, thus forming
a welded joint or weld spot.
[0003] Known vibration welding systems, e.g., ultrasonic welding
systems include various interconnected welding tools. Primary among
these tools are a vibrating sonotrode/welding horn and an anvil
assembly. The anvil assembly may include an anvil body and a rigid
back plate, the latter of which is bolted to a support member such
as a frame, beam, or robot. The workpiece is clamped between the
horn and the anvil body. The welding horn vibrates at a calibrated
frequency in response to an input signal. The anvil body acts as a
reaction surface to the vibrating horn.
[0004] Known methods and processes for joining cables fabricated
from high-tensile strength materials to substrates, and joining
cables formed from shape-memory alloys (SMAs) to substrates include
crimping to form crimped joints, which may affect tensile strength,
fatigue life and electrical resistance of the cables. Other known
methods of joining, e.g., heat-based welding methods, may reduce
the characteristic properties of the SMA cables.
SUMMARY
[0005] A workpiece is described, and includes a substrate, a cable,
and a cover piece. A portion of the cable is joined to the
substrate employing a vibration welding tool, and the cover piece
is interposed between the portion of the cable and the vibration
welding tool during the joining.
[0006] The above and other features and advantages of the present
invention are readily apparent from the following detailed
description of the best modes for carrying out the invention when
taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a schematic side-view illustration of an
embodiment of a workpiece that includes a portion of a cable that
is joined to a substrate with a cover piece positioned overtop, and
an associated vibration welding system, in accordance with the
disclosure;
[0008] FIG. 2 is a schematic isometric illustration of an
embodiment of a workpiece that includes a portion of the cable
joined to the substrate in a lap arrangement with the cover piece
positioned overtop, in accordance with the disclosure;
[0009] FIG. 3 is a schematic isometric illustration of an
embodiment of a workpiece that includes a portion of the cable
joined to the substrate in a lap arrangement with the cover piece
positioned overtop, wherein the portion of the cable is disposed in
a channel formed in the surface of the substrate, in accordance
with the disclosure;
[0010] FIG. 4 is a schematic isometric illustration of an
embodiment of a workpiece that includes a portion of the cable
joined to the substrate in a lap arrangement with the cover piece
positioned overtop, wherein the portion of the cable is formed into
the shape of a hook prior to vibration welding of the cable to the
substrate, in accordance with the disclosure;
[0011] FIG. 5 is a schematic isometric illustration of an
embodiment of a workpiece that includes a portion of the cable
joined to the substrate in a lap arrangement with the cover piece,
wherein the cover piece is a cylindrically-shaped tubular sheath
and the portion of the cable is disposed therein prior to vibration
welding, in accordance with the disclosure;
[0012] FIG. 6 is a schematic isometric illustration of an
embodiment of a workpiece that includes the end portion of a first
cable joined to an end portion of second cable in a butt
arrangement, including a cover piece in the form of a tubular
sheath, and wherein the end portions of the first and second cables
are inserted into the cover piece, in accordance with the
disclosure; and
[0013] FIG. 7 is a schematic isometric illustration of an
embodiment of a workpiece that includes the end portion of a first
cable joined to an end portion of a second cable in a lap
arrangement with the cover piece, wherein the cover piece is a
cylindrically-shaped tubular sheath, and wherein the end portions
of the first and second cables are inserted into the cover piece,
in accordance with the disclosure.
DESCRIPTION
[0014] The components of the disclosed embodiments, as described
and illustrated herein, may be arranged and designed in a variety
of different configurations. Thus, the following detailed
description is not intended to limit the scope of the disclosure,
as claimed, but is merely representative of possible embodiments
thereof. In addition, while numerous specific details are set forth
in the following description in order to provide a thorough
understanding of the embodiments disclosed herein, some embodiments
can be practiced without some or all of these details. Moreover,
for the purpose of clarity, certain technical material that is
known in the related art has not been described in detail in order
to avoid unnecessarily obscuring the disclosure.
[0015] Referring to the drawings, wherein like reference numerals
refer to like components, FIG. 1 schematically shows a workpiece 20
including a portion of a cable 24 having a cover piece 26 overtop
and joined to a substrate 22, and an associated vibration welding
system 10. The cover piece 26 is advantageously interposed between
the portion of the cable 24 and a welding pad 15 of a welding horn
14 of the vibration welding system 10. The portion of the cable 24
may be an end portion of the cable 24 in one embodiment.
Alternatively, the portion of the cable 24 may be any suitable
location along a length of the cable 24. The vibration welding
system 10 may be employed to join the portion of the cable 24 and
cover piece 26 to the substrate 22, as described herein.
[0016] In one embodiment, the cable 24 is a single strand of wire
that is fabricated from a high tensile strength steel that also
preferably has a high Young's modulus. Alternatively, the cable 24
is composed of multiple strands of wire that are fabricated from a
high tensile strength steel. Alternatively, the cable 24 is a
single strand of wire that is fabricated from a shape-memory alloy
(SMA) material. Alternatively, the cable 24 is composed of multiple
strands of the SMA wire. SMA materials are thermo-mechanical
materials that convert energy between mechanical and thermal
domains. SMA examples may include nitinol,
copper-zinc-aluminum-nickel, copper-aluminum-nickel,
iron-manganese-silicon, and nickel-titanium alloys. SMA material
properties may also change in response to application of
electromagnetic fields, and therefore may include an applied field.
Material properties of SMA material may permanently change in
response to exposure to elevated temperatures, including, e.g.,
temperatures that are achieved during known metal welding processes
such as various forms of arc welding.
[0017] The substrate 22 may be any suitable device that is
fabricated from a material to which the cable 24 is to be joined.
The substrate 22 may have a plate shape, a cylindrical shape, or
another suitable shape. The substrate 22 may be formed from
aluminum, copper, steel, thermoplastic polymers or another suitable
material. As shown with reference to FIG. 1, a welding surface 23
of the substrate 22 is planar.
[0018] The cover piece 26 may be in the form of a sheet of material
in one embodiment and as shown. Alternatively, the cover piece 26
may be in the form of a thin, flexible foil element that is capable
of being wrapped around cable elements multiple times, as is shown
with reference to FIG. 7. The cover piece 26 may be fabricated from
any suitable material and is preferably the same material as the
substrate, e.g., aluminum, copper, steel, thermoplastic polymers or
another suitable material. The cover piece 26 may be flat,
corrugated, or have another suitable surface configuration. The
cover piece 26 is interposed between the portion of the cable 24
and a welding pad 15 of a welding horn 14 of the vibration welding
system 10. As such, selected design features of the cover piece 26,
including, by way of example, its thickness, are selected to
prevent or minimize mechanical damage to the portion of the cable
24 that may be induced by the movement of the welding pad 15 of the
welding horn 14 during operation of the vibration welding system
10.
[0019] The vibration welding system 10 is configured for forming
vibration-welded joints using vibrational energy, e.g., ultrasonic
vibration energy. The vibration welding system 10 includes an
actuator in the form of the welding horn 14, a movable head 13, and
an anvil assembly 12 in one embodiment. The welding horn 14 may
also be referred to as a vibrating sonotrode. The vibration welding
system 10 preferably operates in an ultrasonic frequency range,
although other vibration frequency ranges may be employed without
departing from the intended scope of the concepts described
herein.
[0020] The anvil assembly 12 provides a relatively static mass of
metal sufficient for opposing the welding horn 14 during operation
of the vibration welding system 10. The movable head 13 is disposed
to apply compressive pressure to the workpiece 20 against the anvil
body 12 as part of the welding process. The welding horn 14 may be
incorporated into the movable head 13 in one embodiment, or
alternatively, the welding horn 14 may have a separate structure
from the movable head 13.
[0021] The welding horn 14 may include one or a plurality of
welding pads 15 that are disposed to face the workpiece 20 that is
to be welded. The welding pad 15 may have a knurled surface that
includes raised bumps or ridges, or another suitable surface
configuration. The surface of the welding pad 15 physically
contacts the workpiece 20 during the vibration welding process. The
anvil body 12 may likewise have similar anvil pads 25. The welding
pad 15 and the anvil pad 25 serve to grip the workpiece 20 during
the vibration welding process.
[0022] The welding horn 14 couples to a booster 17 and a
piezoelectric stack 16, and a controller 11 is operatively
connected to the piezoelectric stack 16. The piezoelectric stack 16
is a vibrational energy input device. The welding horn 14 may be
caused to vibrate by activation of the piezoelectric stack 16 in
response to a sinusoidal or another repetitive oscillating signal
that is provided from the controller 11. As is understood in the
art, piezoelectric materials are electromechanical materials that
transform energy between mechanical and electric domains.
Piezoelectric materials may be crystalline structures or ceramics
that produce an output voltage signal in response to a mechanical
stress. This effect also occurs in the reverse manner, i.e., a
mechanical displacement or strain is induced in response to a fixed
or oscillating voltage input that is applied to a sample
piezoelectric material. For example, activation of a given
piezoelectric material may result in a change in dimension of
approximately 0.1% for piezo-ceramics and approximately 1% for
piezo-polymers. As such, the piezoelectric stack 16 may vibrate in
response to the repetitive oscillating signal provided from the
controller 11, and the vibration may be propagated through the
booster 17 to the welding pad 15 of the welding horn 14. The
direction of the induced vibration is indicated by arrow 19.
[0023] In one advantageous embodiment, a method for joining the
cable 24 to the substrate 22 can include positioning a portion of
the cable 24 onto a surface of the substrate 22, including
interposing the cover piece 26 overtop of the portion of the cable
24. The substrate 22, the portion of the cable 24 and the cover
piece 26 may be placed onto the anvil 12 of the vibration welding
system 10 such that the cover piece 26 is interposed between the
cable 24 and the welding pad 15 that is attached to the welding
horn 14 of the vibration welding system 10. A compressive force may
be induced by the movable head 13 onto the substrate 22, the
portion of the cable 24 and the cover piece 26 to place the
aforementioned pieces in proximity to each other. The welding horn
14 of the vibration welding system 10 may be activated to apply
ultrasonic vibration energy onto the cover piece 26 to mechanically
join the substrate 22, the cable 24 and the cover piece 26 in a
low-temperature environment.
[0024] FIG. 2 is a schematic isometric illustration of an
embodiment of a workpiece 120 that includes a portion of a cable
124 that is to be joined to a surface 123 of a substrate 122
employing an embodiment of the vibration welding system 10
described with reference to FIG. 1. The workpiece 120 includes the
portion of the cable 124 joined to the substrate 122 in a lap
arrangement with a cover piece 126 positioned overtop to interpose
between the portion of the cable 124 and the welding horn 14 of the
vibration welding system 10. An example location of the vibration
welding is indicated by element 130.
[0025] FIG. 3 is a schematic isometric illustration of another
embodiment of a workpiece 220 that includes a portion of a cable
224 that is to be joined to a surface 223 of a substrate 222
employing an embodiment of the vibration welding system 10
described with reference to FIG. 1. The workpiece 220 includes the
portion of the cable 224 joined to the substrate 222 in a lap
arrangement with a cover piece 226 positioned overtop, wherein the
portion of the cable 224 is disposed in a channel 228 formed in the
surface of the substrate 222. The cover piece 226 is positioned to
interpose between the portion of the cable 224 and the welding horn
14 of the vibration welding system 10. An example location of the
vibration welding is indicated by element 230.
[0026] FIG. 4 is a schematic isometric illustration of another
embodiment of a workpiece 320 that includes a portion of a cable
324 that is to be joined to a surface 323 of a substrate 322
employing an embodiment of the vibration welding system 10
described with reference to FIG. 1. The workpiece 320 includes the
portion of the cable 324 joined to the substrate 322 in a lap
arrangement with a cover piece 326 overtop, wherein the portion of
the cable 324 is formed into the shape of a hook 325 prior to
vibration welding. The cover piece 326 is positioned to interpose
between the portion of the cable 324 and the welding horn 14 of the
vibration welding system 10. An example location of the vibration
welding is indicated by element 330.
[0027] FIG. 5 is a schematic isometric illustration of another
embodiment of a workpiece 420 that includes a portion of a cable
424 that is to be joined to a surface 423 of a substrate 422
employing an embodiment of the vibration welding system 10
described with reference to FIG. 1. The workpiece 420 includes the
portion of the cable 424 joined to the substrate 422 in a lap
arrangement with a cover piece 426, wherein the cover piece 426 is
a cylindrically-shaped tubular sheath having a hollow center
portion, and the portion of the cable 424 is disposed within the
hollow center portion prior to vibration welding. The cover piece
426 is positioned to interpose between the portion of the cable 424
and the welding horn 14 of the vibration welding system 10. An
example location of the vibration welding is indicated by element
430.
[0028] FIG. 6 is a schematic isometric illustration of another
embodiment of a workpiece 520 that may be joined employing an
embodiment of the vibration welding system 10 described with
reference to FIG. 1. The workpiece 520 includes an end portion of a
first cable 524 joined to an end portion of second cable 525 in a
butt arrangement 528 employing a cover piece 526. In one
embodiment, the cover piece 526 is a cylindrically-shaped tubular
sheath, and end portions of the first and second cable 524, 525 are
inserted into opposite ends of the cover piece 526. The cover piece
526 is positioned to interpose between the end portions of the
cable 524, 525 and the welding horn 14 of the vibration welding
system 10. An example location of the vibration welding is
indicated by element 530.
[0029] FIG. 7 is a schematic isometric illustration of another
embodiment of a workpiece 620 that may be joined employing an
embodiment of the vibration welding system 10 described with
reference to FIG. 1. The workpiece 620 includes the end portion of
a first cable 624 joined to an end portion of a second cable 625 in
a lap arrangement 628 employing a cover piece 626. In one
embodiment, the end portions of the first and second cables 624,
625 are on two different cables. Alternatively, the end portions of
the first and second cables 624, 625 are first and second ends of
the same cable, thus forming a continuous loop of the cable. In one
embodiment, the cover piece 626 is a cylindrically-shaped tubular
sheath, and the end portions of the first and second cables 624,
625 are inserted into opposite ends of the cover piece 626.
Alternatively, the cover piece 626 may be in the form of a thin,
flexible foil element that is wrapped multiple times around the end
portions of the first and second cables 624, 625. The cover piece
626 is positioned to interpose between the end portions of the
cables 624, 625 and the welding horn 14 of the vibration welding
system 10. An example location of the vibration welding is
indicated by element 630.
[0030] The welding process and resultant weld joints described
herein advantageously provide high quality joining of high modulus
cables and SMA cables to substrates and to other wire cables
employing vibration welding techniques, which facilitate low-heat
welding to preserve SMA properties. Furthermore, such welding
configurations may prevent notch formation in the cable that may be
caused by knurl patterns employed on welding tip. As such, service
life of the welds may be prolonged, along with increased welding
tool life. This also serves to reduce required packaging space and
thus increases opportunity of implementation of SMA sensors or
actuators.
[0031] While the best modes for carrying out the invention have
been described in detail, those familiar with the art to which this
invention relates will recognize various alternative designs and
embodiments for practicing the invention within the scope of the
appended claims.
* * * * *