U.S. patent application number 12/740897 was filed with the patent office on 2010-10-21 for vehicle occupant safety system with variable support and method of operating the same.
This patent application is currently assigned to Daimler AG. Invention is credited to Werner Bacher, Clark Ruedebusch.
Application Number | 20100264632 12/740897 |
Document ID | / |
Family ID | 40120318 |
Filed Date | 2010-10-21 |
United States Patent
Application |
20100264632 |
Kind Code |
A1 |
Bacher; Werner ; et
al. |
October 21, 2010 |
Vehicle Occupant Safety System with Variable Support and Method of
Operating the Same
Abstract
A vehicle occupant safety system having an airbag prevents an
excessive force from acting upon the thorax of an occupant who has
fastened the seat belt, in the event of an impact. The vehicle
occupant safety system comprises an airbag, a sensor device for
sensing at least one situation parameter and a control device for
controlling the inflation and/or deflation and/or unfolding and/or
positioning of the airbag in dependence of the at least one
situation parameter. The unfolding, position or shape of the airbag
and/or distribution of pressure within the airbag at the end of the
filling phase, is directly or indirectly controlled in a targeted
manner by a control device based on the at least one situation
parameter. A modification of the shape of the airbag in the thorax
region can be obtained in particular by a releasable
constriction.
Inventors: |
Bacher; Werner;
(Sindelfingen, DE) ; Ruedebusch; Clark;
(Holzgerlingen, DE) |
Correspondence
Address: |
CROWELL & MORING LLP;INTELLECTUAL PROPERTY GROUP
P.O. BOX 14300
WASHINGTON
DC
20044-4300
US
|
Assignee: |
Daimler AG
Stuttgart
DE
|
Family ID: |
40120318 |
Appl. No.: |
12/740897 |
Filed: |
October 30, 2008 |
PCT Filed: |
October 30, 2008 |
PCT NO: |
PCT/EP08/09159 |
371 Date: |
April 30, 2010 |
Current U.S.
Class: |
280/735 ;
280/728.1; 280/736; 280/739; 280/743.1; 701/45 |
Current CPC
Class: |
B60R 2021/23115
20130101; B60R 21/01546 20141001; B60R 21/231 20130101; B60R
2021/23384 20130101; B60R 21/233 20130101 |
Class at
Publication: |
280/735 ;
280/728.1; 280/736; 280/739; 280/743.1; 701/45 |
International
Class: |
B60R 21/16 20060101
B60R021/16; B60R 21/26 20060101 B60R021/26; B60R 21/233 20060101
B60R021/233; B60R 21/23 20060101 B60R021/23; G06F 19/00 20060101
G06F019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 2, 2007 |
DE |
102007052247.0 |
Aug 14, 2008 |
DE |
102008037812.7 |
Claims
1-10. (canceled)
11. A vehicle occupant safety system comprising: at least one
airbag; at least one sensor device for sensing at least one
situation parameter; and at least one control device for
controlling at least one of inflation, unfolding, positioning, and
deflation of the airbag based on the at least one situation
parameter; wherein, at least one of the form of the airbag, its
unfolding or positioning, and a distribution of pressure in the
airbag are controlled by the control device in a targeted manner,
based on the situation parameter.
12. The vehicle occupant safety system according to claim 11,
wherein the situation parameter characterizes at least one of an
accident type, accident severity, an impact direction, a type of
occupant, occupant weight, occupant size, occupant contour,
occupant position, occupant kinematics and a belt state.
13. The vehicle occupant safety system according to claim 11,
wherein: The sensor device is operable to detect an imminent or
current accident; and at least one of the shape, unfolding,
positioning, and pressure of the airbag can be changed directly or
indirectly by the control device prior to or during the
accident.
14. The vehicle occupant safety system according to claim 11,
wherein the control device controls at least one of the shape,
unfolding, positioning, and pressure of the airbag directly or
indirectly in such a manner that, if the sensor device recognizes a
closed belt, a region of the airbag predetermined for the support
of the thorax of an occupant delivers less support force than in
the case of a belt which is not closed.
15. The vehicle occupant safety system according to claim 11,
wherein the shape of the airbag can be adapted to a predetermined
or predicted contour in several regions in a different manner.
16. The vehicle occupant safety system according to claim 11,
wherein the airbag has a plurality of segments that are separated
from each other and can be inflated with pressures that are
different from each other or adapted with damping behaviors that
are different from each other.
17. The vehicle occupant safety system according to claim 11,
further comprising active or passive elements for directly or
indirectly changing the shape, unfolding, or positioning of the
airbag, or the distribution of pressure in the airbag.
18. The vehicle occupant safety system according to claim 11,
further comprising means for releasably constricting the
airbag.
19. The vehicle occupant safety system according to claim 18,
further comprising a multi-stage gas generator for inflating the
airbag; wherein the control device for a first release stage of the
gas generator leaves the constriction of the airbag and releases
the constriction for a second release stage.
20. A method for operating a vehicle occupant safety system with an
airbag, said method comprising: sensing at least one situation
parameter; and controlling at least one of inflation, deflation,
unfolding, positioning of the airbag depending on the at least one
situation parameter; wherein at least one of the shape, unfolding,
the positioning, and distribution of pressure within the airbag is
controlled in a targeted manner depending on the at least one
situation parameter.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
[0001] This application is a national stage of PCT International
Application No. PCT/EP2008/009159, filed Oct. 30, 2008, which
claims priority under 35 U.S.C. .sctn.119 to German Patent
Application No. 10 2007 052 247.0, filed Nov. 2, 2007 and No. 10
2008 037 812.7, filed Aug. 14, 2008, the entire disclosures of
which are herein expressly incorporated by reference.
[0002] The present invention relates to a vehicle occupant safety
system, and to an operating method, with at least one airbag, at
least one sensor device for sensing one or more situation
parameters and a control device for the directly or indirectly
controlling inflation, deflation, and/or unfolding, and/or
positioning of the airbag based on the at least one situation
parameter. The present invention further relates to a method for
operating a vehicle occupant safety system.
[0003] When conventional restraint systems are adjusted, it is
necessary to find a good compromise for different accident
situations (type, severity, impact, occupant type, belt state etc.)
with requirements which are often quite different with regard to
the occupant protection. This is so because some parameters of the
airbag of the restraint system are fixed during development, cannot
thereafter be changed, even if the accident situation is or will be
known at least partially during or prior to an accident.
[0004] In addition to considering real accidents, legal
requirements are particularly important during the design of
restraint systems. For example, the legal requirements with regard
to unfastened loads must be satisfied in the USA, so that the
airbag must be designed in such a manner that it alone delays the
occupant sufficiently, as the restraint by a belt is completely
omitted. This is however often counterproductive for low occupant
load in the fastened load cases (e.g., in so-called rating
experiments), as the retaining forces of the belt and the airbag
are added, which additionally takes place in a stepped manner.
[0005] This fundamental problem is increasingly approached by means
of adaptive restraint systems. For this, outflow openings or the
inflation degree of airbags and/or their size are e.g., adapted to
different accident/occupant parameters. German patent document DE
196 10 833 A1, for example, discloses a device for controlling an
occupant restraint system with sensors for sensing the position and
weight of an occupant. A control unit accesses a ventilation device
based on among other things, the occupant's position, his or her
weight or the accident severity, to control the pressure of the gas
in the airbag during its unfolding by controlling the gas amount
guided away from the airbag via the ventilation device. The
ventilation device is thus accessed prior to or during the ignition
of the airbag.
[0006] German patent document DE 40 28 715 A1 further discloses an
airbag which is provided with an outlet valve, which is activated
by the destruction of a closing plate by means of a pyrotechnical
priming charge 30 ms after the actuation of a pressurized gas
source for the airbag. In the activated state, the outlet valve is
adjusted to a predetermined differential pressure in the airbag and
the surroundings.
[0007] It is disadvantageous with these adaptive restraint systems
that, during the adaptation, only parameters of the airbag such as
dampening (outflow opening) or airbag size are changed for the
occupant seen as a unit. Improvements with the most important load
cases are thus limited.
[0008] Furthermore, conventional airbags with a predetermined
outflow and size are known, where the ignition time of at least one
gas generator stage can take place in dependence on e.g., accident
type, accident severity, belt state and seat occupancy. Further
adaptation during or just prior to the accident, however, is no
longer possible. In addition, especially with fastened load cases
in particular for thorax loads, the problem exists that initially
only the belt, and then additionally the airbag, apply their
restraining force. An optimum load which is as even as possible is
thus not possible in principle.
[0009] The automotive industry further has the problem that the
restraint systems have to be designed differently for different
country-specific requirements. This means that the restraint
systems can be designed in a less universal manner and that
additional logistics costs result by means of several airbag
versions.
[0010] Finally, airbags adapted to different body regions are also
known. The respective adaptation is however not adaptive.
[0011] German patent document DE 101 57 710 B4 discloses a method
for accessing a ventilation device of a vehicle airbag where the
ventilation device is brought into an operation-ready state at a
predetermined time after triggering the gas generator. The
ventilation device is opened when the pressure acting on the airbag
which is sensed by the sensor exceeds a limit value. The
ventilation is thus triggered by the pressure signal which is
received by the pressure sensor. The predetermined time and the
limit value for the pressure can be adjusted in dependence on the
seat position or the weight of a vehicle occupant.
[0012] Conventional approaches of adaptive systems thus change the
restraining effect of airbags or belts shortly prior to or during
an accident in dependence on the above-mentioned parameters (e.g.,
in dependence on the belt state). The occupant is thereby however
usually viewed as a unit. The desired decoupling of optimization
measures with regard to their effect for accidents with different
boundary conditions is thus restricted. In addition, there exists
the problem with many previous approaches of adaptive airbags that
the sensor system for decisive improvements is not sufficient or at
least expensive.
[0013] It is thus one object of the present invention to provide an
improved vehicle occupant safety systems (in particular, restraint
systems) in which the effective forces are distributed as optimally
as possible during accidents; that is, e.g., the thorax is not
strained excessively. Furthermore, a corresponding method for
operating a vehicle occupant safety system shall be suggested.
[0014] This and other objects and advantages are achieved by the
occupant safety system according to the invention, which has at
least one airbag, at least one sensor device for sensing one or
more situation parameters and at least one control device for
controlling inflation and deflation, unfolding and/or a positioning
of the airbag in dependence on the at least one situation
parameter. The shape of the airbag or the distribution of pressure
in the airbag can be controlled directly or indirectly in a
targeted manner by the control device in dependence on the one or
more situation parameters.
[0015] A method for operating a vehicle occupant safety system with
an airbag is further provided according to the invention, by
sensing at least one situation parameter and controlling an
inflation and/or deflation and/or unfolding and/or a positioning of
the airbag in dependence on the at least one situation parameter,
wherein the shape of the airbag and/or the distribution of pressure
in the airbag is controlled in a targeted manner in dependence on
the situation parameter.
[0016] A variable airbag support in dependence on environment
parameters can thus be ensured in an advantageous manner. A
reduction of the load on the thorax (e.g., of the thorax
indentation with EU NCAP experiments or the thorax acceleration
with US NCAP experiments) can thus be achieved. A realization can
usually be achieved without an additional sensor system. A
situation parameter, which is sensed by a sensor unit, preferably
represents an accident type, an accident severity, an impact
direction, a type of occupant an occupant weight, an occupant size,
an occupant contour, an occupant position, an occupant kinematics
and/or a belt state. The belt state can for example in particular
be determined by a belt buckle sensor.
[0017] The present invention can in principle be applied to
different types of airbags as e.g., conventional airbags, which are
only supported by the filling gas, support structure airbags or
mechanical airbags.
[0018] According to one further development, an imminent or
occurred accident can be detected with the sensor device and the
shape of the airbag and/or the distribution of pressure in the
airbag prior to and/or during the accident can be changed with the
control device. The risk of injury can be reduced considerably with
the corresponding adaptation.
[0019] In a further embodiment, the control device can control the
shape of the airbag in such a manner that, if the sensor device
recognizes a closed belt, a region of the airbag meant for the
support of the thorax of an occupant supplies less support force
than in the case of a belt which is not closed. Thereby, the thorax
is not excessively strained by the airbag, if high forces already
act thereon by the belts.
[0020] The shape of the airbag can be adapted differently in
several regions to a predetermined and/or predicted contour. Thus,
a suitable support can respectively take place for example for the
head region, the neck region, the shoulder region and the thorax
region of the occupant.
[0021] The airbag can further have several segments, which are
separated from each other and which can be filled with pressures
which are different from each other. A support dependent on the
body region can also be achieved thereby.
[0022] In a further embodiment, the control device has active
and/or passive elements for changing the shape of the airbag and/or
the distribution of pressure in the airbag. The pressure in the
airbag can thus for example be influenced in a purely passive
manner dependent on the speed according to the principle of
Bernoulli. Rebound straps controlled by ignition tablet(s), gas
generator(s) and or electromagnet(s) can e.g., be used as active
elements.
[0023] Furthermore, a means for the releasable or temporary
constriction of the airbag can be arranged thereon. In particular,
a releasable rebound strap can reduce the volume of the airbag at
least in a first release stage. The constriction can be released,
but this is not necessary.
[0024] In an advantageous further development of the invention, a
multi-stage gas generator is provided for inflating the airbag,
wherein the control device for a first release stage of the gas
generator leaves the constriction of the airbag and releases the
constriction for a second release stage. The airbag volume can
thereby be adapted to the inflation volume of the respective gas
generator stage. The release of the constriction can take place not
only directly via the release stage, but also indirectly, e.g., via
the pressure increase by the ignition of a further generator stage.
A release stage of a gas generator/of a gas generator stage can
also contain the function of a control device or be connected
thereto. It is e.g. possible that a rebound strap is released for
the constriction of an airbag by the release of a second generator
stage (e.g, severed).
[0025] Other objects, advantages and novel features of the present
invention will become apparent from the following detailed
description of the invention when considered in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 is a schematic diagram of the support of a vehicle
occupant with a fastened seat belt, by an airbag with rebound
strap; and
[0027] FIG. 2 shows the support of a vehicle occupant with an
unfastened seat belt, by the airbag with released rebound
strap.
DETAILED DESCRIPTION OF THE DRAWINGS
[0028] The embodiments described in more detail in the following
represent preferred embodiments of the present invention.
[0029] According to the invention, the airbag is no longer designed
or adapted to an occupant as a unit, but according to the situation
to individual body regions and/or impact directions. The airbag can
be adapted specially prior to or during an accident for individual
regions (e.g., head, thorax) in dependence on boundary conditions
(as e.g., accident type, accident severity, impact direction, type
of occupant, belt state, etc.) corresponding to the necessary
restraining effect. A decision or adaptation algorithm can possibly
also consider several boundary conditions and put them in relation
to each other.
[0030] With the vehicle occupant safety system according to the
invention, an even more targeted division of the restraining effect
of the airbag on individual body regions in dependence on different
boundary conditions or situations is possible. As the optimization
measures can be decoupled in a better manner for this for the
different boundary conditions, these optimizations are partially
actually only possible for the first time. It is for example
conceivable for fastened load cases that the airbag or airbag only
supports the head, so as to enable a reduction of the thorax load.
For prevalent unfastened load cases, the support by means of the
airbag is however needed.
[0031] A vehicle occupant safety system according to the present
invention can for example be realized in the following
embodiments:
[0032] According to a first embodiment, the shape of the airbag is
adapted to individual body regions according to the situation.
These include for example the omission of regions, which shall be
not be restrained or only be restrained in a reduced manner by the
airbag. According to a second embodiment, the shape of the airbag
adapts to the impact direction in such a manner that a larger part
of the airbag lies between the occupant and the possible impact
surface in the vehicle interior, as would be the case without
adaptation.
[0033] In a third embodiment, the airbag is segmented for
individual body regions. At least one of the regions resulting in
this manner can be adapted according to the situation prior to or
during the restraint. A segment can thereby for example have an
inner pressure, which is different from the other segments. This
can be realized by different damping actions (outflow openings),
inflations or loads/charges etc.
[0034] The characteristics of the three embodiments which have just
been introduced can also be combined with each other, if this is
sensible. The adaptation can further take place in a passive manner
(self-adaptive) and/or in an active manner (e.g.. switchable).
[0035] A concrete embodiment of a vehicle occupant safety system is
introduced in the following by means of FIGS. 1 and 2.
[0036] A vehicle occupant, a passenger in this case, sits in his
seat 2 while being fastened with a seat belt. One part of the belt
3 passes over the thorax of the occupant 1. During an impact, the
belt 3 exerts a force F.sub.G on the thorax of the occupant 1, so
as to restrain him. As the airbag 4 was also released during the
impact, it additionally exerts a pressure F.sub.AB on the thorax.
The two forces F.sub.AB and F.sub.G are added together. In order
that this force does not exceed a predetermined threshold, a
releasable rebound strap 5 is arranged in the airbag 4. This
rebound strap 5 slightly constricts the airbag 4 in the region of
the thorax of the vehicle occupant 1, such that the force F.sub.AB
exerted from the airbag on the thorax is reduced.
[0037] In the present case, it was recognized by a belt buckle
sensor 6 that the vehicle occupant 1 is fastened with a seat belt.
This sensor signal is guided as a situation parameter to a control
device 7, which serves for releasing the airbag 4. The control
device 7 thereby determines a fastened load case, and a holding
device 8 accessed thereby holds the rebound strap 5 for example at
the panel 9. The airbag can thereby not unfold completely in the
thorax region and only exerts a reduced force F.sub.AB on the
thorax. The airbag 4 is supported on the windscreen 10. In the
region of the head of the occupant 1, the airbag is however not
constricted. A force F.sub.AK1 thus acts on the head. No other
force acts on the head, so that only the airbag is responsible for
the restraining of the head.
[0038] By means of the constriction of the airbag 4 in the thorax
region, it mainly acts in the head region when the occupant 1 is
fastened by a seat belt. The restraining force acting on the thorax
can thus be adjusted in a clearly more even or restrained manner.
If a similar ratio of gas filling amount per volume unit is to be
achieved for the cases with/without rebound strap, this can e.g.,
be achieved by the "redistribution" of the airbag volume. For this,
several rebound straps can possibly be useful. (E.g., for the
omission of occupant regions and for the release of division
volumes). A further example with multi-stage gas generators is
listed below.
[0039] In the example of FIG. 2, the occupant 1 is not fastened by
a seat belt. During the impact it is thus necessary that the airbag
does not only restrain the head, but also the thorax region of the
occupant 1 without the help of the belt 3. The belt buckle sensor 6
has recognized that the occupant is not fastened by a seat belt. It
delivers a corresponding sensor signal (situation parameter) to the
control device 7. This determines the unfastened load case and
releases the holding device 8 when impacting. The airbag or the
airbag 4 is thereby not constricted by the rebound strap 5 and
exerts an increased force F.sub.AB' on the thorax of the occupant
1. This increased force F.sub.AB can approximately correspond to
the sum of the reduced airbag force F.sub.AB and the belt force
F.sub.G from the example of FIG. 1.
[0040] The force F.sub.AK2 is exerted on the head of the occupant
1. In order to adapt this force--especially with the ratio to the
force F.sub.AK1--it can be sensible that (e.g., together with the
release of the rebound strap) the damping action of the airbag is
changed, e.g., by opening an additional outflow surface.
[0041] The airbag 4 has a different shape in the example of FIG. 2,
in which the constriction is ineffective, at the end of the
unfolding or filling phase compared to the example of FIG. 1, in
which the constriction acts. According to the situation, the airbag
4 has a shape which is suitable for this situation in its
completely inflated state (maximum inflation state) at the end of
the unfolding or inflation period. The possibly necessary
constriction can thereby also take place by several rebound straps
and/or by (releasable) hold of an airbag region. The
differentiation of the different situations can advantageously take
place as in the above example by means of serial sensors, as the
belt buckle switch here.
[0042] The described airbag with a releasable constriction can be
combined advantageously with a multi-stage (e.g., two-stage) gas
generator. For this, the airbag volume can additionally be adapted
to the inflation volume of the release stage of the gas generator.
This is not the case in this manner with conventional airbags. The
delayed build-up of the internal airbag pressure, which is usual
with multi-stage airbags, can further be avoided with the
constriction during the restraining phase during the ignition of
not all stages, can be accelerated, and an airbag volume which is
not necessary can be avoided. With this special solution, it would
even be conceivable in a simple embodiment that the fastening of
the constriction is for example blown (with a pyrotechnical stage)
or torn (with a pressurized gas stage or with a pyrotechnical
stage) by means of the ignition of the second stage while using the
energy resulting therefrom. A mechanical release while using e.g.,
the released energy is also possible. (E.g., releasing a locking
device by inflow by means of the gas).
[0043] The improved vehicle occupant safety system according to the
invention altogether permits the use of a conventional airbag
system with only slight additions, changes or additional costs.
Possibly, only a releasable constriction with a triggering
algorithm is additionally necessary to obtain an adaptive airbag
system. The remaining components such as the sensor system,
actuator system, cabling etc. are often already present in the
series-production.
[0044] The foregoing disclosure has been set forth merely to
illustrate the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof.
* * * * *