U.S. patent application number 13/975999 was filed with the patent office on 2015-02-26 for active bolster with integrated vent.
This patent application is currently assigned to FORD GLOBAL TECHNOLOGIES, LLC. The applicant listed for this patent is FORD GLOBAL TECHNOLOGIES, LLC. Invention is credited to Stacey H. Raines, Sean B. West.
Application Number | 20150054268 13/975999 |
Document ID | / |
Family ID | 51618858 |
Filed Date | 2015-02-26 |
United States Patent
Application |
20150054268 |
Kind Code |
A1 |
Raines; Stacey H. ; et
al. |
February 26, 2015 |
ACTIVE BOLSTER WITH INTEGRATED VENT
Abstract
An active bolster mounts at an interior trim surface of a
passenger compartment in an automotive vehicle. A plastic-molded,
expandable front wall deploys toward a passenger in the passenger
compartment. A plastic-molded back wall is joined around a
substantially sealed perimeter with the front wall to form an
inflatable bladder. The back wall includes an inflator receptacle
defined by a raised recess wall having an inflator aperture. An
inflator with a gas outlet end and an electrical connector end is
received in the inflator aperture with the gas outlet end inside
the inflatable bladder. The recess wall has a predetermined
thickness for substantially retaining shape during inflation of the
bladder. The inflator receptacle includes a flexible seal disposed
around an inner edge of the inflator aperture comprised of a
flashing edge bearing against the inflator and having a thickness
less than the predetermined thickness of the recess wall.
Inventors: |
Raines; Stacey H.;
(Ypsilanti, MI) ; West; Sean B.; (Monroe,
MI) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
FORD GLOBAL TECHNOLOGIES, LLC |
Dearborn |
MI |
US |
|
|
Assignee: |
FORD GLOBAL TECHNOLOGIES,
LLC
Dearborn
MI
|
Family ID: |
51618858 |
Appl. No.: |
13/975999 |
Filed: |
August 26, 2013 |
Current U.S.
Class: |
280/736 |
Current CPC
Class: |
B60R 2021/0273 20130101;
B60R 21/239 20130101; B60R 21/04 20130101; B60R 21/276 20130101;
B60R 2021/0407 20130101; B60R 2021/0051 20130101 |
Class at
Publication: |
280/736 |
International
Class: |
B60R 21/239 20060101
B60R021/239; B60R 21/276 20060101 B60R021/276 |
Claims
1. An active bolster for mounting at an interior trim surface of a
passenger compartment in an automotive vehicle, comprising: a
plastic-molded, expandable front wall for deploying toward a
passenger in the passenger compartment; a plastic-molded back wall
joined around a substantially sealed perimeter with the front wall
to form an inflatable bladder, wherein the back wall includes an
inflator receptacle defined by a raised recess wall having an
inflator aperture; and an inflator having a gas outlet end and an
electrical connector end; wherein the inflator is received in the
inflator aperture with the gas outlet end inside the inflatable
bladder; wherein the recess wall has a predetermined thickness for
substantially retaining shape during inflation of the bladder; and
wherein the inflator receptacle includes a flexible seal disposed
around an inner edge of the inflator aperture comprised of a
flashing edge bearing against the inflator and having a thickness
less than the predetermined thickness of the recess wall to form a
variable vent.
2. The active bolster of claim 1 wherein the flashing edge is
deflected toward the connector end by the inflator.
3. The active bolster of claim 1 wherein the flashing edge is
elastically distended in response to a predetermined pressure when
the front wall is deployed.
4. The active bolster of claim 3 wherein the elastic distension is
proportional to an applied pressure greater than the predetermined
pressure.
5. The active bolster of claim 1 wherein the inflator comprises a
fastener disposed at the gas outlet end that is fastened to the
recess wall.
6. An active bolster comprising: front and back walls joined around
a periphery defining an inflatable cavity; and an inflator having a
substantially cylindrical body; wherein the inflator body is
inserted through an aperture in the back wall, wherein the aperture
includes a flexible seal disposed around an inner edge comprised of
a flashing edge bearing against the inflator that elastically
distends and vents in response to a predetermined pressure in the
cavity.
7. The active bolster of claim 6 wherein the flashing edge is
deflected away from the cavity by the inflator.
8. The active bolster of claim 6 wherein the elastic distension is
proportional to an applied pressure greater than the predetermined
pressure.
9. The active bolster of claim 6 wherein the inflator comprises a
fastener disposed at the gas outlet end that is fastened to the
back wall.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] Not Applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH
[0002] Not Applicable.
BACKGROUND OF THE INVENTION
[0003] The present invention relates in general to active bolsters
for occupant crash protection in automotive vehicles, and, more
specifically, to an active bolster with an inflatable bladder
formed by plastic wall panels that is vented to manage deflation
during impact.
[0004] An active bolster is a vehicle occupant protection device
with a gas-inflatable bladder to absorb impacts and reduce trauma
to occupants during a crash. As opposed to deployable air bag
cushions made of various fabrics that emerge from behind various
openings upon inflation, active bolsters use the interior trim
surface itself to expand at the beginning of a crash event for
absorbing the impact and dissipating energy through the action of
an inflation gas. U.S. Pat. No. 8,205,909, issued Jun. 26, 2012,
incorporated herein by reference, discloses an active knee bolster
integrated into a glove box door that is light weight and visually
attractive. U.S. Pat. No. 8,474,868, issued Jul. 2, 2013, also
incorporated herein by reference, discloses a typical structure
wherein an active bolster includes a front wall or panel (i.e., a
trim panel) that faces a vehicle occupant attached to a back wall
or panel (i.e., bladder wall) along a sealed periphery. One or both
of the walls is deformable in order to provide an inflatable
bladder. For example, the back wall may have a pleated (i.e.,
accordion-like) region that straightens out during inflation. The
walls are initially spaced apart by a small amount when in their
pre-deployment, non-inflated condition. This allows ingress of the
inflation gas in a manner that achieves an even inflation across
the panel.
[0005] The front and back walls of a typical bladder for an active
bolster are comprised of molded thermoplastics such as
polyethylene, polyolefin, or PVC. They are typically injection
molded but can also be blow molded. When formed separately, the
front and back walls must be hermetically joined around their
periphery in order to form the inflatable bladder. The joint must
be strong to resist separation that could result from the high
pressures during inflation. The peripheral seal is formed by hot
welding, for example.
[0006] It is known that in order to optimize the dissipation of
energy when an occupant contacts an air bag or an active bolster,
inflation gas should be vented to allow a controlled collapse of
the airbag that safely decelerates the impacting occupant. U.S.
Pat. No. 8,328,233, issued Dec. 11, 2012, which is incorporated
herein by reference, discloses a variable vent for an active
bolster wherein the vent has a low flow rate at low pressures and a
higher flow rate at higher pressures across the vent. The reduced
flow rate of the vent during initial stages of inflation permits
the use of a smaller (less costly) inflator, while the higher vent
flow rate at higher pressures helps ensure the integrity of the
peripheral weld by limiting the pressure rise and avoiding large
tearing forces that could cause the seal to fail.
[0007] Various types of structures have been disclosed for venting
an adaptive amount of inflation gas during inflation and during
loading by an impacting passenger. For example, hinged flaps
providing a small opening at low pressure and a larger opening at
higher pressure have been formed in the back bladder wall. The
size, placement, and desired performance characteristics for an
active bladder are typically unique for each vehicle model that is
developed by a vehicle manufacturer. Since the bladder wall may be
redesigned for each new vehicle design, a significant development
effort must be is devoted to finding an appropriate placement and
configuration for one or more vent features according to the unique
design specifications. It would be desirable to provide a venting
structure that is usable across many different designs and that
reliably provides an appropriate amount of venting (including no
venting, i.e., a sealed condition) at the appropriate times.
SUMMARY OF THE INVENTION
[0008] In one aspect of the invention, an active bolster is
provided for mounting at an interior trim surface of a passenger
compartment in an automotive vehicle. A plastic-molded, expandable
front wall deploys toward a passenger in the passenger compartment.
A plastic-molded back wall is joined around a substantially sealed
perimeter with the front wall to form an inflatable bladder. The
back wall includes an inflator receptacle defined by a raised
recess wall having an inflator aperture. An inflator with a gas
outlet end and an electrical connector end is received in the
inflator aperture with the gas outlet end inside the inflatable
bladder. The recess wall has a predetermined thickness for
substantially retaining shape during inflation of the bladder. The
inflator receptacle includes a flexible seal disposed around an
inner edge of the inflator aperture comprised of a flashing edge
bearing against the inflator and having a thickness less than the
predetermined thickness of the recess wall to form a variable
vent.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a rear perspective view of a prior art inflatable
bladder assembly of an active bolster.
[0010] FIG. 2 is a rear, perspective view of a portion of a back
bladder wall with an inflator receptacle of the present
invention.
[0011] FIG. 3 is a cross section through the inflator receptacle of
FIG. 2 without an inflator.
[0012] FIG. 4 is a cross section through the inflator receptacle of
FIG. 2 with an inflator.
[0013] FIG. 5 is a partial cross-sectional view showing the venting
of inflation gas at a flexible seal formed around the inflator.
[0014] FIG. 6 illustrates the insertion of an inflator into an
inflator receptacle to engage the flexible seal.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0015] Referring now to FIG. 1, an inflatable bladder 10 for an
active bolster has a plastic-molded front wall 11 and a
plastic-molded, expandable back bladder wall 12. Walls 11 and 12
are joined around a closed perimeter region 13 to form an
inflatable bladder having an open central volume or cavity between
walls 11 and 12 to receive an inflation gas from an inflator 14
mounted in a receptacle or recess 15 of back wall 12 during a crash
event. Back wall 12 includes a plurality of pleats, such as 16 and
17, to accommodate the expansion of back wall 12 during inflation.
A plurality of bosses 18 are used to mount back wall 12 to a
reaction surface. Vent holes 20 comprised of an asterisk-shaped
pattern cut through inner wall 12 are used for venting the central
volume prior to and during inflation.
[0016] During a crash event, the inflator fires releases inflation
gas which expands the bladder and moves the front trim wall toward
the occupant. Managing the pressure within the bladder and the
resulting stress applied to the hermetic weld seam in a way that
simultaneously obtains the required knee loads is a difficult
balancing act. If there is not enough pressure relief within the
system then the stress on the weld seam when the bladder becomes
loaded by an impact of the occupant's knees may be high enough to
blow out the hermetic weld seam, resulting in complete loss of
pressure within the system. If there is too much venting within the
system, then while the weld seam stays intact the system cannot
generate the required knee loads for occupant restraint.
[0017] Vents such as star-shaped holes 20 may allow excessive gas
leakage upon deployment, resulting in a greater than desired loss
of pressure within the system. Thus, it has been difficult to
maintain sufficient pressure in order to obtain the knee loads
required for good occupant restraint.
[0018] In a preferred embodiment of the invention, no molded-in
vent holes are created in the bladder walls. Instead, a flash
sleeve is provided at the edge of an inflator-receiving hole of the
bladder in order to create a snug fit to the inflator when
installed. This sleeve maintains an initial seal which allows the
bladder to expand and inflate to a high pressure. When the bladder
becomes loaded by an impact of the knees, pressure is relieved
through a gap that opens up between the inflator and the flash
sleeve. The resulting pressure relief experienced by the bladder is
directly related to the force acting upon the bladder by the
impacting knees. The softness of the bladder material and the
thickness of the flash sleeve are selected to provide a desired
flexibility so that a self-regulating vent is created having
desired pressure characteristics.
[0019] FIG. 2 illustrates an embodiment of the invention wherein a
plastic-molded back wall 25 (which is joined around a substantially
sealed perimeter with a front wall (not shown) to form an
inflatable bladder) has an inflator receptacle 26 defined by a
raised recess wall. An inflator unit 27 is installed in an inflator
aperture 28 formed in the raised recess wall. An electrical
connector 30 is coupled to a control module (not shown) via a
mating connector and wiring 31. A threaded mounting stud 32 that
extends from inflator unit 27 passes through the raised recess wall
of receptacle 26 to receive a nut 33 that is tightened sufficiently
to obtain a seal against any leakage of inflation gas.
[0020] FIG. 3 shows a cross section of receptacle 26 through
inflator aperture 28, revealing a flexible seal disposed
circumferentially around the inner edge of inflator aperture 28
which is comprised of a flashing edge 35 for bearing against the
inflator. More particularly, flashing edge 35 may preferably be
formed by a thinning of the wall along the edge of aperture 28 to a
thickness T.sub.2, compared to a greater thickness T.sub.1 of the
surrounding portions of receptacle 26. Thickness T.sub.1 has a
predetermined value which is configured to substantially retain the
shape of receptacle 26 during inflation of the bladder. Thickness
T.sub.2 is less than the predetermined value of T.sub.1 so that it
has the flexibility necessary to form a variable, self-regulating
vent. Due to its flexibility, flashing edge 35 starts to become
elastically distended when a predetermined pressure is reached
within receptacle 26 after the front wall of the bladder has been
deployed during an inflation event. Furthermore, an amount of
elastic distention that is obtained is preferably proportional to
an amount by which the instantaneous applied pressure exceeds the
predetermined pressure.
[0021] FIG. 4 shows a cylindrical body 36 of inflator 27 after
installing it into the inflator aperture so that flashing edge 35
is deflected as a result of the diameter of body 36 being greater
than the diameter of the opening created by flashing edge 35. In
one embodiment, an inflator was used having a diameter of about 20
mm. The diameter of the aperture without the flashing edge (i.e.,
where the wall begins to thin) was 21 mm, and the diameter of the
aperture within the flashing edge was 18 mm.
[0022] The deflection of flashing edge 35 causes it to bear against
inflator body 36 with sufficient force to maintain a seal as long
as internal bladder pressure is below the predetermined pressure.
When internal pressure increases above the predetermined pressure,
flashing edge 35 is elastically distended as shown in FIG. 5 to
create a vent path 37. The variable size of path 37 depends on
(e.g., is proportional to) the internal pressure.
[0023] A preferred method of the mounting of inflator unit 27 into
the raised recess of receptacle 26 is shown in FIG. 6. Inflator 27
has an electrical connector end 40 and a gas outlet end 41. From
the interior side of back bladder wall 25, connector end 40 is
moved from the position shown in dashed lines through the inflator
aperture, thereby deflecting flashing edge 35 toward connector end
40 as it moves into its final position shown in solid lines. An
electrical plug 42 is then joined with connector end 40 and a
mounting stud (not shown) near gas outlet end 41 is inserted
through a mounting hole 43 in the side of receptacle 26. A gasket
and a nut are threaded onto the stud in order to fasten gas outlet
end 41 inside the inflatable bladder.
[0024] An inflator receptacle is a feature which would typically be
employed in almost any active bolster design for different unique
vehicle applications. A self-regulating vent formed by a flashing
edge around the outside of the aperture that receives the inflator
body provides for easy design and development resulting in low cost
and improved results.
* * * * *