U.S. patent application number 11/952503 was filed with the patent office on 2008-09-04 for prestressing fixture to eliminate automotive p.s.i.r. door-chute vibration weld visibility.
Invention is credited to Gregg S. Evans.
Application Number | 20080211208 11/952503 |
Document ID | / |
Family ID | 39732531 |
Filed Date | 2008-09-04 |
United States Patent
Application |
20080211208 |
Kind Code |
A1 |
Evans; Gregg S. |
September 4, 2008 |
PRESTRESSING FIXTURE TO ELIMINATE AUTOMOTIVE P.S.I.R. DOOR-CHUTE
VIBRATION WELD VISIBILITY
Abstract
An automotive interior component including an airbag chute
having at least one weld bar, and a pre-stressed instrument panel
having a substrate layer for bonding to the weld bar. The
pre-stressing provides tensile stress at weld bar bonding areas to
reduce any deformation visible on an exposed surface of the
instrument panel.
Inventors: |
Evans; Gregg S.; (Windsor,
CA) |
Correspondence
Address: |
DYKEMA GOSSETT PLLC
FRANKLIN SQUARE, THIRD FLOOR WEST, 1300 I STREET, NW
WASHINGTON
DC
20005
US
|
Family ID: |
39732531 |
Appl. No.: |
11/952503 |
Filed: |
December 7, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60873274 |
Dec 7, 2006 |
|
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Current U.S.
Class: |
280/728.3 |
Current CPC
Class: |
B32B 38/0012 20130101;
B60R 21/2165 20130101; B29C 65/08 20130101; B23K 20/10
20130101 |
Class at
Publication: |
280/728.3 |
International
Class: |
B60R 21/215 20060101
B60R021/215 |
Claims
1. An automotive interior component comprising: an airbag chute
having at least one weld bar; and a pre-stressed instrument panel
having a substrate layer for bonding to the weld bar, wherein
tensile stress at weld bar bonding areas in the pre-stressed
instrument panel reduces any deformation visible on an exposed
surface of the pre-stressed instrument panel due to shrinkage of
weld melted instrument panel material.
2. An automotive interior component according to claim 1, wherein
the weld bar of the airbag chute is vibration welded to the
substrate layer.
3. An automotive interior component according to claim 1, further
comprising a cover layer bonded to the substrate layer.
4. An automotive interior component according to claim 3, wherein
the cover layer is made of one of polyvinyl chloride and
ThermoPlastic Olefin.
5. An automotive interior component according to claim 3, wherein
the cover layer is about 0.4-1.0 mm thick.
6. An automotive interior component according to claim 1, further
comprising a cover layer and an intermediate foam layer bonded to
the substrate layer.
7. An automotive interior component according to claim 6, wherein
the foam layer is made of polypropylene.
8. An automotive interior component according to claim 6, wherein
the foam layer is about 0.5-3.0 mm thick.
9. An automotive interior component according to claim 1, wherein
the substrate layer includes thermoplastic polymers.
10. An automotive interior component according to claim 1, wherein
the substrate layer is about 2.0-4.0 mm thick.
11. An apparatus for manufacturing a pre-stressed automotive
instrument panel for eliminating distortion in an area of vibration
welded airbag chutes, said apparatus comprising: a weld fixture
including a plurality of convex pre-stressors disposable against an
instrument panel for creating compression in an area of contact
with an instrument panel and creating tension in a surface opposite
the contact area upon application of vacuum to draw the instrument
panel toward the weld fixture.
12. An apparatus according to claim 11, wherein the weld fixture is
disposable against a cover layer of the instrument panel and
creates tension in a substrate layer of the instrument panel, the
substrate layer being disposed adjacent an opposite face of the
cover layer with or without an intermediate foam layer being
disposed between the cover and substrate layers.
13. A method of manufacturing an automotive instrument panel for
eliminating distortion in an area of vibration welded air bags,
said method comprising: providing a weld fixture including a
plurality of pre-stressor protrusions; placing the pre-stressor
protrusions against an instrument panel; generating a force to
press the weld fixture against the instrument panel to create
compression in an area of contact of the weld fixture with the
instrument panel and tension in a surface opposite the contact
area; and vibration welding an air bag chute to the instrument
panel such that a weld bar of the air bag chute is welded to the
surface placed in tension.
14. A method according to claim 13, the instrument panel further
comprising a substrate layer, a foam layer attached to the
substrate layer, and a cover layer attached to the foam layer,
wherein placing the pre-stressor protrusions includes placing the
pre-stressor protrusions against the cover layer of the instrument
panel, and wherein vibration welding further comprises vibration
welding an air bag chute to the substrate layer.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of priority to
Provisional Application Ser. No. 60/873,274, filed Dec. 7, 2006,
incorporated by reference in its entirety.
BACKGROUND OF INVENTION
[0002] a. Field of Invention
[0003] The invention relates generally to automotive instrument
panels, an apparatus for and method of manufacture thereof, and,
more particularly, to an apparatus for and method of manufacturing
automotive instrument panels and other automotive components which
eliminates distortion in the area of vibration welded Passenger
Side Inflatable Restraint (PSIR) chutes and other vibration welded
components.
[0004] b. Description of Related Art
[0005] Automobiles are commonly equipped with airbags for reducing
driver and passenger injuries in the case of an accident.
Automobile airbags are generally located in areas where a driver or
passenger would potentially contact an automobile interior in the
event of an accident. Airbags can reduce injuries by providing a
substantially non-solid surface for the driver or passenger to
contact, as opposed to the generally solid surfaces of the
automotive interior. Although the functionality of the airbag is
greatly valued, the visual appeal of the instrument panel, and
invisibility of the airbag system are also of value to automobile
manufacturers and consumers alike.
[0006] In order to install an airbag, the airbag is generally
folded into a module that is installed into or behind an automotive
interior component. The module housing a passenger-side airbag is
generally installed on the underside of an instrument panel, within
a PSIR chute protruding behind the instrument panel. The instrument
panel will generally have a pre-weakened area, allowing an airbag
to release therethrough. A PSIR chute will be bonded to the
instrument panel, and will generally include doors that line up
with the pre-weakened area of the instrument panel.
[0007] A known method for attaching a PSIR chute to an instrument
panel includes vibration welding the PSIR chute to the instrument
panel. Vibration welding joins components by "rubbing" them
together, creating heat through the friction, melting the
connection points, and applying/holding pressure until the
components cool together, thereby welding the components at the
contact points. During the cooling process, there is known to be
shrinkage/deformation of materials. Namely, during the known
vibration welding of an instrument panel and PSIR chute, there is a
visible deflection of the instrument panel at the connection points
between the components caused by uneven shrinkage during the
cooling process.
[0008] It would therefore be of benefit to provide an apparatus and
method of manufacturing automotive instrument panels and other
structures including air bags and other vibration welded components
to include a flat (or predetermined contoured) appearance in the
area of the vibration welds.
SUMMARY OF THE INVENTION
[0009] The present invention overcomes the drawbacks and
deficiencies of known methods and apparatus for attaching a PSIR
chute to an instrument panel by providing an automotive interior
component including an airbag chute having one or more weld bars
and a pre-stressed instrument panel having a substrate layer for
bonding to the weld bar. For the instrument panel, tensile stress
at weld bar bonding areas reduces any deformation visible on an
exposed surface of the pre-stressed instrument panel, by matching
the "B" surface stretch under the tensile stress of local bending
to the expected shrink of the melted layer.
[0010] For the automotive interior component described above, the
weld bars of the airbag chute may be vibration welded to the "B"
side of the plastic instrument panel. The interior component may
further include a cover layer bonded to the substrate layer. The
cover layer may be made of polyvinyl chloride or ThermoPlastic
Olefin, and in an exemplary embodiment, may have a thickness of
0.4-1.0 mm. The interior component may further include a cover
layer and an intermediate foam layer bonded to the substrate layer.
The foam layer may be made of polypropylene, and in an exemplary
embodiment, may have a thickness of 0.5-3.0 mm. The substrate layer
may include thermoplastic polymers, and in an exemplary embodiment,
may have a thickness of 2.0-4.0 mm.
[0011] The invention also provides an apparatus for pre-stressing
an automotive instrument panel for eliminating distortion in an
area of vibration welded airbag chutes. The apparatus may include a
weld fixture including a plurality of convex pre-stressors
disposable against an instrument panel for creating compression in
an area of contact with an instrument panel and creating tension in
a surface opposite the contact area upon application of vacuum to
draw the instrument panel toward the weld fixture. The weld fixture
may be disposable against a cover layer of the instrument panel and
creates tension in a substrate layer of the instrument panel, with
the substrate layer being disposed adjacent an opposite face of the
cover layer with or without an intermediate foam layer being
disposed between the cover and substrate layers.
[0012] The invention yet further provides a method of manufacturing
an automotive instrument panel for eliminating distortion in an
area of vibration welded air bags. The method may include providing
a weld fixture including a plurality of pre-stressor protrusions,
and placing the pre-stressor protrusions against an instrument
panel. The method may also include generating a force to press the
weld fixture against the instrument panel to create compression in
an area of contact of the weld fixture with the instrument panel
and tension in a surface opposite the contact area, and vibration
welding an air bag chute to the instrument panel such that a weld
bar of the air bag chute is welded to the surface placed in
tension.
[0013] For the method described above, the instrument panel may
also include a substrate layer, a foam layer attached to the
substrate layer, and a cover layer attached to the foam layer. For
the method described above, placing the pre-stressor protrusions
includes placing the pre-stressor protrusions against the cover
layer of the instrument panel, and vibration welding further
includes vibration welding an air bag chute to the substrate
layer.
[0014] Additional features, advantages, and embodiments of the
invention may be set forth or become apparent from consideration of
the following detailed description, drawings, and claims. Moreover,
it is to be understood that both the foregoing summary of the
invention and the following detailed description are exemplary and
intended to provide explanation without limiting the scope of the
invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate preferred
embodiments of the invention and together with the detail
description serve to explain the principles of the invention. In
the drawings;
[0016] FIG. 1 is a view illustrative of a related art instrument
panel and PSIR chute, prior to vibration welding of the PSIR chute
to the instrument panel;
[0017] FIG. 2A is a view illustrative of the related art instrument
panel construction of FIG. 1, illustrating various distortions in
the instrument panel visible surface due to vibration welding of
the PSIR chute;
[0018] FIG. 2B is an enlarged view of the related art instrument
panel construction of FIG. 1, illustrating distortion in the area
of the center score weakening line;
[0019] FIG. 3 is a view illustrative of a modified weld fixture
surface for pre-stressing of the instrument panel according to the
present invention;
[0020] FIG. 4 is a view illustrating pre-stressing of the
instrument panel according to the present invention;
[0021] FIG. 5 is a view illustrating vibration welded attachment of
a PSIR chute;
[0022] FIG. 6A is a view illustrative of a pre-stress layered
instrument panel according to the present invention, illustrating a
PSIR chute vibration welded thereon; and
[0023] FIG. 6B is an enlarged view of the pre-stressed layered
instrument panel of FIG. 6A for absorbing any distortions from
vibration welding of the PSIR chute.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0024] Referring now to the drawings wherein like reference
numerals designate corresponding parts throughout the several
views, FIGS. 1-2B are views illustrative of a related art
instrument panel construction, FIGS. 3-5 are views illustrative of
an instrument panel construction for eliminating distortion in the
area of vibration welded PSIR chutes according to the present
invention, and FIGS. 6A and 6B are views illustrative of a
pre-stressed layered instrument panel according to the present
invention.
[0025] Referring to FIG. 1, in "hard hidden" constructions, a PSIR
Chute 10 is often vibration welded to the underside of prior art
instrument panel 12. As briefly discussed above, the technique of
vibration welding generally involves the physical movement PSIR
Chute 10 having weld bars 14 relative to prior art instrument panel
12, with weld bars 14 being moved horizontally relative to
instrument panel 12 under pressure. This physical movement creates
heat which melts contact area 16 of prior art instrument panel 12,
and thus allows weld bars 14 to be welded to prior art instrument
panel 12 upon cooling of areas 16 when the relative movement is
stopped.
[0026] Referring to FIGS. 2A and 2B, upon cooling, the thermal
shrinkage in contact areas 16 causes compression in areas 16 and
tension in the opposite visible areas 18 of the prior art
instrument panel. Further, the thermal shrinkage in contact areas
16 also causes bending in area 20 of center score line 22.
[0027] Referring to FIG. 3, the present invention generally
provides an instrument panel construction technique using a
modified weld fixture 32 (illustrated as a lower weld fixture in
FIG. 3) including a plurality of spaced convex pre-stressors 34. In
the embodiment illustrated, each pre-stressor 34 may be a smooth
convex curved shape, however protrusions of various configurations
may be used to transfer the desired force to the instrument panel.
Referring to FIGS. 3-5, each pre-stressor 34 may be disposed
adjacent visible surface 36 of instrument panel 38 and is further
disposed opposite weld bars 14. Referring to FIG. 3, each
pre-stressor 34 may include a predetermined height to bend
instrument panel 38 such that the tension induced stretch on the
back surface 40 matches the expected weld shrink to thus eliminate
distortion in the area of weld bars 14. Where the technique is used
on a pre-stressed layered instrument panel (as discussed below),
pre-stressors 34 may be disposed adjacent to a cover layer and
tension may be on substrate layer 30 (refer to FIG. 6B). Modified
weld fixture 32 may further include a plurality of holes (not
shown) for creating compression in areas 42 and tension in areas 44
of instrument panel 38 upon the application of a vacuum to draw
instrument panel 38 toward fixture 32. A vacuum seal (not shown)
may be provided around instrument panel 38 for creating a vacuum as
discussed above. Although a vacuum force is described herein, those
skilled in the art would appreciate the application of similar
forces to the modified weld fixture 32 and instrument panel 38.
Namely, instead of using vacuum to draw instrument panel 38 toward
weld fixture 32, weld fixture 32 (and another upper weld fixture
(not shown) for holding the air bag chute) may be simply pressed
against instrument panel 38 (and air bag chute 46) to thus create
the aforementioned compressed/tensioned areas.
[0028] The manufacturing method of instrument panel 38 according to
the present invention will now be described in detail with
reference to FIGS. 3-5. As shown in FIG. 3 and briefly discussed
above, instrument panel 38 may be disposed relative to modified
weld fixture 32, with visible surface 36 of instrument panel 38, or
the surface of substrate layer 30 adjacent foam layer 28 of
pre-stressed layered instrument panel 24 as shown in FIG. 6B (see
discussion below), being disposed in contact with pre-stressors 34
of weld fixture 32. The instrument panels may be laterally aligned
relative to weld fixture 32 such that each pre-stressor 34 is
disposed opposite the weld bars 14. A vacuum may then be created to
draw instrument panel 38 (or 24 of FIGS. 6A and 6B) towards weld
fixture 32 via the holes (not shown) in weld fixture 32. In an
exemplary embodiment of the present invention, the vacuum may be
generated at 13 psi, with the instrument panel being maintained at
room temperature. Further, in an exemplary embodiment, weld fixture
32 (and the weld fixture for air bag chute 46) may be machined
aluminum and include a thin (i.e. 1/3 mm) urethane layer to prevent
scratching or damage to the grain of instrument panel 38 (or 24 of
FIGS. 6A and 6B).
[0029] Referring to FIG. 4, after vacuum application, instrument
panel 38 (or 24 of FIGS. 6A and 6B) may include compression in
areas 42 and tension in areas 44 to thus create an uneven
instrument panel visible surface prior to vibration welding of air
bag chute 46.
[0030] Referring next to FIG. 5, with weld fixture 32 held in place
relative to instrument panel 38 (or 24 of FIGS. 6A and 6B), air bag
chute 46 including weld bars 14 (and another upper weld fixture
(not shown) for holding the air bag chute) may be vibration welded
to instrument panel 38. Upon cooling of weld areas 44, the initial
stretch due to tension in areas 44 (see FIG. 4) is matched by the
thermal shrinkage created by cooling of weld areas 44 to thus
create a horizontal (or otherwise predetermined contoured)
instrument panel visible surface 36 without distortion.
[0031] Referring now to FIGS. 6A and 6B, as briefly discussed
above, in an alternative embodiment of the instrument panel, PSIR
Chute 10 having weld bars 14 may be vibration welded to
pre-stressed layered instrument panel 24 at contact areas 16. As
shown in FIG. 6B, pre-stressed layered instrument panel 24 may
include cover layer 26, which may be about 0.4-1.0 mm of polyvinyl
chloride, ThermoPlastic Olefin, a blend of polypropylene,
polyethylene and/or rubber, or like thermoplastic polymers, Panel
24 may further include a foam layer 28 including polypropylene foam
or like material of about 0.5-3.0 mm thickness, and a substrate
layer of 30 of 2.0-4.0 mm thick ThermoPlastic Olefin or like
material. Substrate layer 30 may be formed by an injection molding
process. Cover layer 26 and foam layer 28 may be vacuum wrapped
over the substrate layer 30. Weld bars 14 may be vibration molded
at contact areas 16 to substrate layer 30.
[0032] Whereas visible distortion in areas 18 and center area 20
appear in the related art (see FIGS. 2A and 2B), distortions are
not visible through the pre-stressed layered instrument panel 24,
as the pres-stressed combination of substrate layer 30, foam layer
28, and cover layer 26 act to absorb any distortion caused by
vibration welding. Whereas the embodiment of pre-stressed layered
instrument panel 24 has been described as being formed by placement
of convex pre-stressors 34 adjacent the surface of substrate layer
30 adjacent foam layer 28, it is conceivable that pre-stressors 34
may be placed on the exposed surface of cover layer 26.
[0033] Those skilled in the art would readily appreciate in view of
this disclosure that various modifications may be made to the
instrument panel construction technique described above, without
departing from the scope of the present invention. For example,
while instrument panel construction technique has generally been
discussed in conjunction with vibration welded assembly of air
bags, this technique may be readily used with other vibration
welded components for eliminating distortion in the area of the
vibration weld. Further, while the use of pre-stressors 34 has been
discussed for eliminating distortion in an instrument panel,
pre-stressors 34 may be also used as needed to create a
predetermined contoured appearance in the area of an instrument
panel or other structures for providing a desirable contoured
aesthetic appearance.
[0034] Although particular embodiments of the invention have been
described in detail herein with reference to the accompanying
drawings, it is to be understood that the invention is not limited
to those particular embodiments, and that various changes and
modifications may be effected therein by one skilled in the art
without departing from the scope or spirit of the invention as
defined in the appended claims.
* * * * *