U.S. patent application number 10/380461 was filed with the patent office on 2004-03-18 for gas generator.
Invention is credited to Ishida, Takeshi, Kishino, Yoshiyuki, Kodama, Ryoi, Matsumura, Yasushi, Yoshida, Masahiro.
Application Number | 20040053182 10/380461 |
Document ID | / |
Family ID | 27481620 |
Filed Date | 2004-03-18 |
United States Patent
Application |
20040053182 |
Kind Code |
A1 |
Yoshida, Masahiro ; et
al. |
March 18, 2004 |
Gas generator
Abstract
A gas generator S of the present invention comprises an
elongated cylindrical housing 1 closed at both ends thereof, a
combustion chamber 2, formed in the housing 1 at one end portion
thereof, for packing gas generant 3 that is burnt to generate high
temperature gas, an igniter device 5, fixed in the housing 1 at one
end thereof, for igniting and burning the gas generant 3 packed in
the combustion chamber 2, a filtering member 4, inserted in the
housing 1 and set at the other end portion of the housing 1, and
gas discharge holes 6 formed at the other end of the housing 1 to
communicate between an inside of the housing 1 and an outside of
the same with respect to an axial direction of the housing 1.
Inventors: |
Yoshida, Masahiro;
(Himeji-shi, JP) ; Ishida, Takeshi; (Himeji-shi,
JP) ; Kishino, Yoshiyuki; (Himeji-shi, JP) ;
Kodama, Ryoi; (Himeji-shi, JP) ; Matsumura,
Yasushi; (Himeji-shi, JP) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Family ID: |
27481620 |
Appl. No.: |
10/380461 |
Filed: |
March 19, 2003 |
PCT Filed: |
September 10, 2001 |
PCT NO: |
PCT/JP01/07849 |
Current U.S.
Class: |
431/352 |
Current CPC
Class: |
B60R 21/18 20130101;
B60R 2021/2612 20130101; B60R 21/2644 20130101 |
Class at
Publication: |
431/352 |
International
Class: |
F23D 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 19, 2000 |
JP |
2000-283039 |
Jan 12, 2001 |
JP |
2001=4766 |
Feb 19, 2001 |
JP |
20001-41224 |
Jun 13, 2001 |
JP |
2001-178154 |
Claims
1. (Canceled)
2. (Canceled)
3. (Canceled)
4. (Canceled)
5. (Canceled)
6. (Canceled)
7. (Canceled)
8. (Canceled)
9. (Canceled)
10. (Canceled)
11. (Canceled)
12. (Added) A gas generator comprising an elongated cylindrical
housing (1) closed at one end thereof, a combustion chamber (2),
formed in the housing (1) at one end portion thereof, for packing
as generant (3) that is burnt to generate high temperature gas, an
igniter device (5), fixed in the housing (1) at one end thereof,
for igniting and burning the gas generant (3) packed in the
combustion chamber (2), a gas discharge tube (40) having a
communication hole (35) formed in the housing (1) to communicate
between an inside of the combustion chamber (2) and an outside of
the same and a gas discharge hole (6) formed at a tip thereof, and
a filtering member (4), provided between the gas discharge hole (6)
and the combustion chamber (2), to cool the high temperature gas
and collect the slag contained in the high temperature gas, wherein
the gas discharge tube (40) has therein a space for the high
temperature gas to pass through and has the gas discharge hole (6)
formed at a tip thereof and a second filtering member (46) formed
between the space and the gas discharge hole formed at the tip.
13. (Added) The gas generator according to claim 12, wherein the
gas generant (3) is contained in a metal cup (22) fixed in the
combustion chamber (2).
14. (Added) The gas generator according to claim 12, which
comprises diffusing means (31) for changing a gas flow centrally
running from the combustion chamber (2) toward the filtering member
(4).
15. (Added) The gas generator according to claim 13, which
comprises diffusing means (31) for changing a gas flow centrally
running from the combustion chamber (2) toward the filtering member
(4).
16. (Added) The gas generator according to claim 12, wherein the
gas discharge hole (6) has a diameter made smaller than a diameter
of the housing (1).
17. (Added) The gas generator according to claim 12, wherein a
baffle plate (47) is provided on a projected plane of the filtering
member (4) at the combustion chamber (2) side on which the
communication hole (35) is projected.
18. (Added) The gas generator according to claim 17, wherein the
baffle plate (47) has an area as large as not less than 50% of the
projected plane on which the communication hole (35) is
projected.
19. (Added) The gas generator according to claim 17, wherein the
baffle plate (47) has an area equal to or larger than a projected
area of the projected plane on which the communication hole (35) is
projected.
20. (Added) The gas generator according to claim 12, wherein the
gas discharge tube (40) is provided at the other end (41) of the
housing (1) to be eccentric from an axis of the housing (1).
21. (Added) The gas generator according to claim 12, wherein the
gas discharge tube (40) is adapted to change the gas flow.
Description
TECHNICAL FIELD
[0001] The present invention relates to a gas generator suitable
for inflating an airbag, particularly for inflating an elongated
hollow seatbelt (an air-belt).
BACKGROUND ART
[0002] In order to protect a vehicle occupant from the shock at a
car collision, an air-belt, which is an airbag of a sort, has been
developed in recent years. The air-belt is an elongated hollow
seatbelt that is inflated by introducing gas therein at a car
collision. This type of seatbelt is inflated by clean gas
discharged from a gas generator, in common with other types of
airbags. However, the gas generator used for the air-belt is
required to be disposed in a limited space, such as an interior of
a buckle of the seatbelt arranged in proximity to the vehicle
occupant seat.
[0003] In recent years, reduction in size of the buckle of the
seatbelt and improvement in design of the same have been
increasingly demanded, along with which limitations have been being
imposed on the shape and size of the air-belt gas generator
arranged in the inner space of the buckle of the seatbelt and
reduction in size of the air-belt gas generator has also been
demanded.
[0004] Also, in order to meet the demand on the environment and
safety, the tendency has been in recent years to shift from azide
gas generant using sodium azide to gas generant using
nitrogen-containing organic compound. However, since the gas
generant using the nitrogen-containing organic compound is less
ignitable than the azide gas generant, the gas generant using the
nitrogen-containing organic compound need be increased in
flammability to ignite it, as compared with the azide gas generant.
Due to this, the air-belt gas generator is structured to produce an
increased thermal energy of the flame from the igniter, as compared
with the conventional airbag gas generator.
[0005] It is the object of the present invention to provide an
air-belt gas generator suitable for inflating the elongated hollow
seatbelt
DISCLOSURE OF THE INVENTION
[0006] The present invention provides a gas generator comprising an
elongated cylindrical housing closed at one end thereof a
combustion chamber, formed in the housing at one end portion
thereof, for packing gas generant that is burnt to generate high
temperature gas, an igniter device, fixed in the housing at one end
thereof, for igniting and burning the gas generant packed in the
combustion chamber, a gas discharge tube having a communication
hole formed in the housing to communicate between an inside of the
combustion chamber and an outside of the same and a gas discharge
hole formed at a tip thereof, and a filtering member, provided
between the gas discharge hole and the combustion chamber, to cool
the high temperature gas and collect the slag contained in the high
temperature gas, wherein the gas discharge tube has therein a space
for the high temperature gas to pass through and has the gas
discharge hole formed at a tip thereof and a second filtering
member formed between the space and the gas discharge hole formed
at the tip.
[0007] In this gas generator, the gas generant packed in the
combustion chamber is ignited and burnt from the one axial end of
the housing by the igniter device, to generate a large amount of
high temperature gas. The high temperature gas generated in the
combustion chamber flows through the filtering member in the axial
direction of the housing, for collection of the slag and cooling of
the gas. Thereafter, the filtered gas is discharged from the gas
discharge hole in the form of the clean gas. The clean gas is
discharged axially from the other axial end of the housing through
the gas discharge hole communicating between an inside of the
housing and an outside of the same with respect to the axial
direction.
[0008] In addition, in this gas generator, the gas discharge tube
is separately provided at the housing. This enables the gas
generator to be reduced in size. This also enables the air-belt to
be inflated instantaneously by connecting the gas discharge tube
with a gas inlet port of the air-belt. Further, the provision of
the second filtering member at the tip of the gas discharge tube
enables the slag and the like contained in the gas to be collected
reliably.
[0009] As a result of this, the clean gas generated in the housing
is discharged with concentration in the axial direction of the
housing. This can allow the clean gas to be fed into the airbag or
the elongated hollow seatbelt of the air-belt directly, without
changing the gas flow at the outside of the gas generant to inflate
the airbag or the seatbelt instantaneously.
[0010] In the gas generator according to the present invention, the
gas generant is contained in a metal cup fixed in the inner wall of
the combustion chamber.
[0011] Since the gas generant is contained in the combustion
chamber of the housing in the state of being packed in the metal
cup, the gas generant can be protected from being charged with
moisture.
[0012] The gas generator according to the present invention further
comprises diffusing means for changing a gas flow centrally running
from the combustion chamber toward the filtering member.
[0013] The diffusing means can suppress the direct injection of the
high temperature gas from the gas generant into the filtering
member. As a result of this, the possibility of the filtering
member being damaged can be suppressed.
[0014] In the gas generator according to the present invention, the
gas discharge hole has a diameter made smaller than a diameter of
the housing.
[0015] Since the gas discharge hole has a diameter made smaller
than a diameter of the housing, an impulsive force of the gas
generated in the combustion chamber in the housing and discharged
therefrom can be increased.
[0016] In the gas generator according to the present invention, a
baffle plate is provided on a projected plane of the filtering
member at the combustion chamber aide on which the communication
hole is projected.
[0017] Since the baffle plate is provided on a projected plane of
the filtering member on which the communication hole is projected,
the need of increasing the strength of the filtering member can be
eliminated. Also, the provision of the baffle plate can prevent the
gas from being concentrated on the projected plane of the filtering
member on which the communication hole is projected, and as such
can allow the effective use of the entire filtering member. As a
result of this, the filtering member can be allowed to have a bare
minimum of thickness, and as such can provide a reduced size of the
gas generator.
[0018] In the gas generator according to the present invention, the
baffle plate has an area as large as not less than 50% of the
projected plane on which the communication hole is projected.
[0019] Since the baffle plate has an area as large as not less than
50% of the projected plane on which the communication hole is
projected, a portion of the filtering member corresponding to the
projected plane on which the communication hole is projected, on
which the high temperature gas is concentrated, can be protected
from the gas when discharged. Also, this construction of the baffle
plate can prevent the gas from being concentrated on the projected
plane of the filtering member on which the communication hole is
projected, and as such can allow the effective use of the entire
filtering member.
[0020] In the gas generator according to the present invention, the
baffle plate has an area equal to or larger than a projected area
of the projected plane on which the communication hole is
projected.
[0021] Since the baffle plate has an area equal to or larger than a
projected area of the projected plane on which the communication
hole is projected, a portion of the filtering member corresponding
to the projected plane on which the communication hole is
projected, on which the high temperature gas is concentrated, can
be protected from the gas when discharged. Also, this construction
of the baffle plate can prevent the gas from being concentrated on
the projected plane of the filtering member, and as such can allow
the effective use of the entire filtering member.
[0022] In the gas generator according to the present invention, the
gas discharge tube is provided at the other end of the housing to
be eccentric from an axis of the housing.
[0023] Since the gas discharge tube is provided at the other end of
the housing to be eccentric from an axis of the housing,
installation of the gas generator in the interior of the buckle of
the seatbelt and the like can be facilitated. Also, the position of
the gas discharge tube may be properly selected in accordance with
the positional relationship between the gas discharge tube and the
gas inlet port of the seatbelt.
[0024] As a result of this, when the gas generator is installed in
the buckle of the seatbelt and the like, the gas discharge tube can
be adapted to the shape and size of the buckle. This can facilitate
the connection of the gas discharge tube to the gas inlet port of
the seatbelt.
[0025] In the gas generator according to the present invention, the
gas discharge tube is adapted to change the gas flow.
[0026] Since the gas discharge tube is adapted to change the gas
flow, the gas generator may be disposed in the buckle, depending on
the shape of the buckle of the seatbelt.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a sectional view of a gas generator of the first
embodiment according to the present invention.
[0028] FIG. 2 is a diagram taken along arrowed line A-A of FIG.
1.
[0029] FIG. 3 is a sectional view of a gas generator of the second
embodiment according to the present invention.
[0030] FIG. 4 is a sectional view of a gas generator of the third
embodiment according to the present invention.
[0031] FIG. 5 is a sectional view of a gas generator of the fourth
embodiment according to the present invention.
[0032] FIG. 6 is a sectional view of a gas generator of the fifth
embodiment according to the present invention.
[0033] FIG. 7 is a sectional view of a gas generator of the sixth
embodiment according to the present invention.
[0034] FIG. 8 is a sectional view of a gas generator of the seventh
embodiment according to the present invention.
[0035] FIG. 9 is a sectional view of a gas generator of the eighth
embodiment according to the present invention.
[0036] FIG. 10 is a sectional view of a gas generator of the ninth
embodiment according to the present invention.
[0037] FIG. 11 is a sectional view of a gas generator of the tenth
embodiment according to the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
[0038] The gas generator of the first embodiment according to the
present invention will be described with reference to FIGS. 1 and
2. FIG. 1 is a sectional view of the gas generator. FIG. 2 is a
diagram taken along arrowed line A-A of FIG. 1.
[0039] The gas generator S shown in FIG. 1 is mainly used for
inflating a seatbelt of an air-belt. The gas generator S comprises
an elongated cylindrical housing 1, a combustion chamber 2 in the
housing 1, gas generants 3, a filtering member 4, an igniter 5
serving as an igniter device, and gas discharge holes 6. It is to
be noted that the air-belt is an elongated hollow seatbelt that is
mounted on a vehicle occupant seat and is inflated by introducing
therein the clean gas discharged from the gas generator S.
[0040] As shown in FIG. 1, the housing 1 comprises an outer
cylinder plug 7 and an outer cylinder 8. The outer cylinder plug 7
has a plug body 9, a plug lug 10 reduced in diameter and projecting
from one axial end of the plug body 9, and a radially projecting
flange 11 formed between the plug body 9 and the plug lug 10. The
outer cylinder plug 7 has a stepped through-hole 12 formed to
axially extend therethrough from the other axial end of the plug
body 9 to an axial end of the plug lug 10. The stepped through-hole
12 comprises a fixing hole 13 opening into the other axial end of
the plug body 9 and extending to a place close to the plug lug 10,
and a gas passage hole 14 reduced in diameter and extending through
the plug lug 10. The plug body 9 has a threaded portion, formed
around the outside of the plug body 9, for engaging directly or
indirectly into the seatbelt of the air-belt through piping and the
like.
[0041] As shown in FIG. 1, the housing 1 is structured to have an
elongated cylindrical form by inserting the plug lug 10 of the
outer cylinder plug 7 into the outer cylinder 8. The outer cylinder
plug 7 is fixed to the outer cylinder 8 by crimping the outer
cylinder plug 7 onto the outer cylinder 8. In the crimping process,
an axial end portion of the outer cylinder 8 is projected into an
annular groove 15 of the plug lug 10 to form an annular projection
16. As a result of this, the outer cylinder plug 7 and the outer
cylinder 8 are integrally combined with each other by engagement
between the annular groove 15 and the annular projection 16.
[0042] As shown in FIG. 1, the housing 1 is closed at one end
thereof (on the outer cylinder 8 side) by fixing thereto a holder
17 holding the igniter 5 and is provided with a stop plate 18 with
gas discharge holes 6 fixed at the other end thereof (on the outer
cylinder plug 7 side). The holder 17 is fitted in the outer
cylinder 8 at an axial end portion thereof to close the housing 1
at the end thereof by crimping the outer cylinder 8 onto the holder
17. In the crimping process, an axial end portion of the outer
cylinder 8 is projected into an annular groove 19 of the holder 17
to form an annular projection 20. The stop plate 18 with the gas
discharge holes 6 is inserted from an axial end of the plug body 9
into a larger diameter hole 21 forming a fixing hole 13 and then is
fixed to the other end portion of the housing 1 by crimping the
axial end portion 9a of the plug body 9, The gas passing through
the filtering member 4 is discharged from the gas discharge holes 6
of the stop plate 18. In the crimping process, the axial end
portion 9a of the plug body 9 is bent radially inwardly to crimp
the stop plate 18 to a stepped portion of the larger diameter hole
21. As a result of this, the interior of the housing 1 is
partitioned by the holder 17 and the stop plate 18, to form the
combustion chamber 2 between the holder 17 fixed in the housing 1
at the one axial end thereof and the outer cylinder plug 7.
[0043] As shown in FIG. 1, the combustion chamber 2 in the housing
1 communicates with the fixing hole 13 in the housing 1 at the
other axial end thereof via the gas passage hole 14. The gas
generant 3 that generates high temperature gas by burning is packed
in the combustion chamber 2. The gas generant 3 is contained in a
metal cup 22 fitted in the combustion chamber to extent along an
inner wall thereof. The cup 22 is formed in a cup-like shape from a
thin metal, such as aluminum, and is inserted from a bottom 22a of
the cup into the combustion chamber 2. The bottom 22a of the cup 22
closes the gas passage hole 14. The cup 22 serves as moisture proof
of the gas generant 3 packed in the combustion chamber 2 and also
serves to regulate inner pressure of the combustion chamber 2. In
addition, the cup 22 serves as a burst plate which is burst when
the inner pressure of the cup 22 exceeds a predetermined pressure.
The gas generant 3 is covered by cushioning members 23, 24, 25 to
protect the gas generant 3 from being powdered by oscillation. The
cushioning members 23, 24, 25 are sequentially fitted in the space
between the holder 17 and the cup 22, to prevent oscillation of the
cup 22 itself. The cushioning member 25 contactable with the gas
generant 3 has a cross-shaped notch to ensure that the flame
spurted from the Igniter 5 serving as an igniter device is
transferred to the gas generant 3 without dulling and delay. The
cushioning members 23-25 are preferably formed from elastic
material, such as silicon rubber and silicon foam.
[0044] As shown in FIG. 1, the filtering member 4 is formed, for
example, from a knitted wire sheet, a plain-woven wire sheet or an
aggregation of crimped metal wire rods into a cylindrical shape to
have substantially the same diameter as an inner diameter of the
fixing hole 13 of the plug body 9. The filtering member 4 is fixed
in the fixing hole 13 of the housing 1, so that it is placed in the
housing 1 at the other axial end portion thereof. Also, the
filtering member 4 abuts with a stepped portion of the fixing hole
13 at one axial end thereof on the gas passage hole 14 side and
extends to a position near the stop plate 18 at the other axial end
thereof. The filtering member 4 is abutted against the stepped
portion of the fixing hole 13 by a plurality of expanded metals 26
interposed between the stop plate 18 and the filtering member 4.
Each expanded metal 26 has a number of gas passage holes for
allowing the gas to pass therethrough and functions as a spring.
The expanded metals 26 may be laminated in layers.
[0045] As shown in FIG. 1, the igniter 5 serving as the igniter
device is an electric igniter that is ignited when an electric
current flows through it. The igniter 5 is fitted into the holder
17 from the inside of the combustion chamber 2 and fixed to the
holder 17 whose end comes to be the one axial end of the housing 1.
Also, the igniter 5 extends through the cushioning members 23, 24,
25 and projects toward the combustion chamber 2 to confront the cup
22. The igniter S is ignited when an electric current flows through
it in accordance with collision signals from a collision detecting
sensor, to spurt the flame into the combustion chamber 2. As a
result of this, the cup 22 is melted to forcibly ignite and burn
the gas generant 3 packed in the cup 22.
[0046] As shown in FIG. 1, the plurality of gas discharge holes 6
are formed in the stop plate 18 whose end comes to be the other
axial end of the housing 1. The gas discharge holes 6 extend
through the housing 1 in the axial direction of the housing 1 and
communicate between the outside of the housing 1 and the fixing
hole 13. Also, the gas discharge holes 6 are arranged at the inside
of the crimped axial end portion 9a of the plug body 9 and are
formed at and circumferentially about the axis of the housing 1, as
shown in FIG. 2. As a substitute for the plurality of gas discharge
holes 6, a single gas discharge hole may be formed at the axis of
the housing.
[0047] Now, operation of the gas generator S1 will be described
with reference to FIG. 1. It should be noted that the gas generator
S1 shown in FIG. 1 is connected directly or indirectly with the
inside of the seatbelt of the air-belt at the other axial end of
the housing 1.
[0048] When the collision sensor detects automobile collision, the
gas generator S1 ignites the igniter 5 by the passage of the
electric current through it, as shown in FIG. 1. The flame from the
igniter 5 melts the cup 22 and bursts up the cushioning member 25,
first, and, then, the flame is spurted into the combustion chamber
2 to forcibly ignite and burn the gas generant 3 to thereby produce
the high temperature gas. The ignition and burning of the gas
generant 3 is transferred from the one axial end of the housing 1
toward the filtering member 4 sequentially.
[0049] When the combustion in the combustion chamber 2 proceeds and
the inner pressure of the combustion chamber 2 rises up to a
predetermined pressure, the bottom 22a of the cup 22 is burst or
burnt at a break line portion thereof to communicate the interior
of the combustion chamber 2 with the filtering member 4. The high
temperature gas generated in the combustion chamber 2 flows through
the gas passage hole 14 and in turn the filtering member 4 in the
axial direction of the housing 1, through which slag is collected
and the gas is cooled to produce clean gas. After passing through
the expanded metals 26, the clean gas is discharged from the gas
discharge holes 6 and is fed into the seatbelt of the air-belt
directly. At this time, the clean gas is discharged with
concentration via the gas discharge holes 6 along the axial
direction of the housing 1. As a result of this, the seatbelt of
the air-belt is inflated instantaneously by the clean gas
discharged from the gas discharge holes 6.
[0050] The high temperature gas generated in the combustion chamber
2 flows through the filtering member 4 along the axial direction of
the housing 1, and as such displaces the filtering member 4 toward
the stop plate 18 at the other end of the housing 1. If the axial
end portion 9a of the plug body 9 is crimped insufficiently, the
filtering member 4 may be dropped out of the housing 1. Therefore,
the axial end portion 9a of the plug body is crimped so strongly
that the filtering member 4 cannot be dropped out of the housing 1.
In addition, the number of the gas discharge holes 6 formed and the
diameter of the same are properly selected to suppress the
displacement of the filtering member 4. Further, when the expanded
metals 26 are pressed by the filtering member 4 displaced toward
the stop plate 18, the expanded metals 26 act to limit the
displacement of the filtering member 4 toward the stop plate 18,
while ensuring the gas passages for the clean gas to pass
through.
[0051] As just described, since the gas generator S1 of this
embodiment enables the clean gas generated in the housing 1 to be
discharged with concentration in the axial direction of the housing
1, the clean gas can be fed into the seatbelt of the elongated
hollow seatbelt directly, without changing the flowing direction of
the gas. As a result of this, the seatbelt of the air-belt can be
inflated instantaneously.
[0052] Also, since the gas generator S1 enables the clean gas to be
discharged with concentration in the axial direction of the housing
1, there is no need of any means for changing the flowing direction
of the gas. This enables the seatbelt of the air-belt to be mounted
in a narrow space of the vehicle occupant seat, thus providing
reduction in space for the air-belt gas generator.
[0053] Shown in FIG. 3 is the second embodiment of the gas
generator according to the present invention. The same reference
characters as those in FIG. 1 or 2 refer to the corresponding
members, with detailed explanation thereon omitted.
[0054] As shown in FIG. 3, the gas generator S2 of this embodiment
is provided with a closed-end-cylinder-shaped inner wall 30 having
holes 31 formed in the periphery thereof that serve as gas
diffusion means. The inner wall 30 is fitted in the fixing hole 13
for fixing the filtering member 4 in the outer cylinder plug 7 at a
portion thereof on the gas passage hole 14 side. A wire mesh 32 is
disposed around the outside of the inner wall 30 in contact with
the fixing hole 13. This can produce the result that the gas
generated by the burning of the gas generant 3 in the combustion
chamber 2 passes 6 through the gas passage hole 14 and then passes
through the holes 31 formed in the periphery of the inner wall 30.
When passing through the holes 31, the gas is discharged radially
from the holes 31. Then, the gas runs into the wire mesh 32
disposed in internal touch with the outer cylinder plug 7, first,
and, then, runs along the axial direction of the housing 1, passing
through the filtering member 4. Thereafter, the filtered gas is
discharged from the gas discharge holes 6 in the form of the clean
gas.
[0055] As a result of this, the high temperature and high pressure
gas from the combustion chamber 2 is prevented from being spurted
directly into the filtering member 4. This can prevent the
filtering member 4 from being damaged by the high temperature and
high pressure gas, and as such can allow the filtering member 4 to
fulfill its function to collect the slag and the like.
[0056] Shown in FIG. 4 is the third embodiment of the gas generator
according to the present invention. The same reference characters
as those in FIGS. 1 through 3 refer to the corresponding members,
with detailed explanation thereon omitted.
[0057] The gas generator S3 according to this embodiment comprises
the gas generant 3 packed in the combustion chamber 2 formed at one
end of the outer cylinder 8, the filtering member 4 fixed in the
outer cylinder 8 at the other end thereof, the igniter 5 for
igniting and burning the gas generant 3, and a gas discharge tube
40 projected toward the other end 41 of the outer cylinder 8, as
shown in FIG. 4. The gas discharge tube 40 is formed by narrowing
an outer diameter of the outer cylinder 8 at the other end 41
thereof. The gas discharge tube 40 is extended in parallel with an
axis of the outer cylinder 8 and also extended eccentrically with
respect to the axis of the outer cylinder S. The gas discharge tube
40 is formed to have the gas passage hole 14 therein and have a gas
discharge hole 6 at its tip, like a chimney. Also, the gas
discharge tube 40 is provided, at a portion thereof on the
combustion chamber 2 side, with a communication hole 35 to
communicate between the inside of the combustion chamber 2 and the
outside of the same. The filtering member 4 is provided between the
gas discharge hole 6 and the combustion chamber 2 and is fixed in
vicinity of the communication hole 35 at the combustion chamber 2
side in the condition in which it is pressed toward the expanded
metal 26 by the expanded metal 26 and a stop plate 44. Then, after
the gas generant 3 and the cushioning members 25, 23 are inserted
into the combustion chamber 2 sequentially from the other end 41
side of the outer cylinder 8 (from the filtering member 4 side),
the holder 17 crimped onto the igniter 5 is inserted in the
combustion chamber 2. As a result of this, the gas generated by the
burning of the gas generant 3 in the combustion chamber 2 passes
through the filtering member 4 and then the filtered gas flows from
the communication hole 35 into the gas passage hole 14 in the gas
discharge tube 40 and then is discharged from the gas discharge
hole 6 in the form of clean gas. When the gas passes through the
gas passage hole 14, the remaining slag in the gas that was not
collected by the filtering member 4 is adhesively collected via an
inner wall of the gas discharge tube 40.
[0058] This can produce the result that even when the filtering
member 4 is damaged by the high temperature and high pressure gas
spurted from the combustion chamber 2 directly to the filtering
member 4, the slag and the like can be collected by the gas
discharge tube 40.
[0059] In addition, since the gas discharge tube 40 having the gas
discharge hole 6 is provided eccentrically, when the gas generator
is used, for example, for the air-belt or the inflatable seatbelt,
the installation of the gas generator in the buckle of the seatbelt
can be facilitated. It should be noted that the gas discharge tube
40 need not be provided eccentrically with respect to the axis of
the outer cylinder 8. The gas discharge tube 40 may be provided
coaxially with respect to the axis of the outer cylinder 8. Also,
the gas discharge tube 40 may be properly formed in accordance with
the configuration of the buckle of the seatbelt.
[0060] Alternatively, the gas discharge tube 40 may be bent at its
tip portion 42, as the gas generator S4 of the fourth embodiment
according to the present invention shown in FIG. 5. This bending of
the gas discharge tube 40 enables the gas flow to be changed
easily. The bending angle may be properly changed in accordance
with the configuration of the seatbelt or its buckle. This enables
the gas generator to be connected with the seatbelt by bending the
gas discharge tube in accordance with the configuration of the
seatbelt or its buckle.
[0061] Further, according to the gas generator S4 of this
embodiment the clean gas generated in the housing 1 is discharged
from the gas discharge tube 40 formed in the chimney form, the
clean gas can be fed into the elongated hollow seatbelt directly,
without spoiling the design of the seatbelt, the buckle and the
like. As a result of this, the seatbelt of the air-belt can be
inflated instantaneously.
[0062] Shown in FIG. 6 is the fifth embodiment of the gas generator
according to the present invention. The gas generator S5 shown in
FIG. 6 is modification of the gas generator S4 shown in FIG. 4, In
the gas generator S5, the gas discharge tube 40 is closed at its
tip, but instead, the gas discharge holes 6 are formed
circumferentially at a predetermined space around the gas discharge
tube 40 at a portion thereof near the tip. As a result of the gas
discharge holes 6 being circumferentially formed around the gas
discharge tube 40, the gas flow is changed, so that the gas is
discharged radially with respect to the gas discharge tube 40. This
can provide the result that for example when this gas generator is
connected with the seatbelt, the seatbelt can be uniformly
inflated.
[0063] Shown in FIG. 7 is the sixth embodiment of the gas generator
according to the present invention. In the gas generator S6 shown
in FIG. 7, a communication hole 35 is formed in the form of an
orifice having a small diameter which is formed about an axis of
the outer cylinder 8 of the housing 1 at the other end 9 side and
the gas discharge tube 40 is provided in which the gas passage hole
14 is provided coaxially or eccentrically with respect to the axis
of the orifice 43(35). The gas generated in the combustion chamber
2 passes through the filtering member 4 and the expanded metal 26
and in turn through the orifice 43(35) and is discharged from the
gas discharge hole 6 formed at the tip of the gas discharge tube
40. Since the gas passes through the orifice 43(35), the gas
generated in the combustion chamber 2 can be regulated to a desired
amount of discharged gas by selecting the size of the orifice
43(35).
[0064] As just described, since the gas passes through the orifice
43(35) having a reduced diameter, the gas from the combustion
chamber 2 stays at the orifice 43(35) for a while, first, and,
then, flows into the gas passage hole 14 in the gas discharge tube
40. This can provide an increased slag-in-gas collection rate of
the filtering member 4. This enables the gas discharge tube 40 to
be increased in diameter, as compared with the gas generators S3 to
S5 shown in FIGS. 4 to 6. Therefore, the gas discharge tube 40 may
be made equal in diameter to the outer cylinder 8 of the housing 1,
as the gas generator S7 shown in FIG. 8, in addition to the gas
generator S6 illustrated in this embodiment.
[0065] Shown in FIG. 9 is the eighth embodiment of the gas
generator according to the present invention. The gas generator S8
shown in FIG. 9 features in that the gas discharge tube 40 is
formed at the other end 41 of the outer cylinder 8 of the housing 1
so as to be parpendicular to the axis of the outer cylinder 8. The
gas generator S8 according to this embodiment comprises the
cup-shaped housing 1 closed at the other end 41 and the igniter 5
serving as the igniter device, fixed in the housing 1 at one end
thereof, for igniting and burning the gas generant 3 in the
combustion chamber 2. In the gas generator S8 according to this
embodiment, the gas discharge hole 40 is oriented perpendicularly
to the outer cylinder 8 and is communicated with the combustion
chamber 2 through the orifice 43(35) formed in the periphery of the
outer cylinder 8, as shown in FIG. 9. The ring-shaped expanded
metal 26 is fixed in the combustion chamber 2 to extend along the
inner wall of the housing 1 so as to cover the orifice 43(35). The
filtering member 4 is fitted in around the inside of the
ring-shaped expanded metal 26. The expanded metal 26 and the
filtering member 4 are pressed toward the other end 41 of the
housing 1 by a ring-shaped stop member 44. The ring-shaped stop
member 44 also serves to prevent the gas generated in the
combustion chamber 2 from flowing Into the expanded metal 26
directly.
[0066] The gas generated in the combustion chamber 2 passes through
the filtering member 4 and in turn through the orifice 43(35)
formed in the periphery of the outer cylinder 8. Then, the filtered
gas flows into the gas passage hole 14 of the gas discharge tube 40
and is discharged from the gas discharge hole 6 formed at the tip
of the gas discharge tube 40. As just described, since the gas
discharge tube 40 may be formed in the periphery of the outer
cylinder 8 to extend perpendicularly to the axis of the outer
cylinder 8, the installation of the gas generator in accordance
with the configuration of the seatbelt or its buckle can be
facilitated.
[0067] Shown in FIG. 10 is the ninth embodiment of the gas
generator according to the present invention. The gas generator S9
shown in FIG. 10 is modification of the gas generator S3 of FIG. 4.
In the gas generator S9, a filtering member 46 and an expanded
metal 45 are fixed in the gas discharge tube 40 at its tip portion.
As just described, as a result of the filtering member 46 being
fixed in the gas discharge tube 40 at its tip portion, the gas
discharged from the gas generator S9 is cooled down to an adequate
temperature and also the remaining slag that was not collected by
the filtering member 4 and the inner surface of the gas can be
collected reliably. It should be noted that the construction
wherein the filtering member 46 and the expanded metal 45 are fixed
in the gas discharge tube 40 at its tip portion may be adopted in
the gas generators S3 to S8 previously illustrated in FIGS. 4 to 9,
as well as in the gas generator S9 shown in FIG. 10.
[0068] Additionally, the gas generator S3 of FIG. 4 may be
modified, as the gas generator S110 of the tenth embodiment
according to the present invention as shown in FIG. 11, for
example. Specifically, in the gas generator S3 of FIG. 4, the
filtering member 4 may be provided, on a plane thereof on which the
communication hole 35 is projected, with a baffle plate 47 having
an area as large as not less than 50% of the projected area. The
same reference characters as those in FIG. 4 refer to the
corresponding members, with detailed explanation thereon
omitted.
[0069] The high temperature gas generated by the burning of the gas
generant 3 is apt to concentrate on the projected plane of the
filtering member 4 close to the communication hole 35 when
discharged from the combustion chamber, for the reason of which the
filtering member 4 must be increased in strength. As a result of
the baffle plate 47 being disposed on a portion of the filtering
member 4 corresponding to the projected plane on which the
communication hole 35 is projected, the concentration of the gas on
the projected plane of the filtering member on which the
communication hole 35 is projected can be prevented. Therefore, the
need of increasing the strength of the filtering member 4 can be
eliminated. This enables the filtering member 4 to be reduced in
thickness and thus enables the gas generator S to be reduced in
size.
[0070] It should be noted that the construction that the baffle
plate 47 is disposed on the projected plane on which the
communication hole 35 is projected may be adopted in the gas
generators S6 to S9 previously illustrated in FIGS. 5 to 10, as
well as in the gas generator S10 shown in FIG. 11.
[0071] It is preferable that the baffle plate 47 has an area as
large as not less than 50% of the projected area of the projected
plane on which the communication hole 35 is projected. It is
further preferable that the baffle plate 47 has an area equal to or
larger than the projected area of the projected plane on which the
communication hole 35 is projected.
[0072] The gas generator according to the present invention may
take other forms such as the following forms, without being limited
to those illustrated in FIGS. 1 to 11.
[0073] (1) While the gas generator according to the present
invention is suitably used for inflating the seatbelt of the
air-belt, it can be used for inflating the airbag and for actuating
the seatbelt pretensioner. When applied to this airbag or seatbelt
pretensioner, the gas generator according to the present invention
enables the airbag to be inflated instantaneously or the seatbelt
pretensioner to be actuated instantaneously by discharging the
clean gas with concentration from the gas generator in the axial
direction of the housing 1.
[0074] (2) In place of the construction of the housing 1 comprising
the outer cylinder plug 7, the outer cylinder 8, the holder 17 and
the stop plate 18, the gas generator according to the present
invention may adopt the favorable-in-strength construction of the
housing 1 comprising a closed-end-cylinder-shaped outer cylinder
and a holder for closing the outer cylinder at an opening side
thereof. In this alternate construction, a plurality of axially
perforated gas discharge holes are formed in the bottom of the
outer cylinder.
[0075] (3) In place of the construction that the interior of the
combustion chamber 2 is shielded from the filtering member 4 side
by the bottom 22a of the cup 22, the gas generator according to the
present invention may adopt the construction that the interior of
the combustion chamber is shielded from the filtering member 4 side
by the burst plate. In this alternate construction, it is
preferable that seal rings are inserted in between the annular
groove 15 and the annular projection 16 and between the annular
groove 19 and the annular projection 20, respectively, for moisture
proof of the gas generant 3 in the combustion chamber 2. It is also
preferable that another seal ring is inserted in between the
igniter 5 and the holder 17. The gas generator according to the
present invention may adopt the construction that the burst plate
is adhesive bonded to the stop plate 18 to close the gas discharge
holes 6. When the inner pressure of the combustion chamber or the
inner pressure of the entire housing 1 rises up to a predetermined
pressure, the burst plate is burst to discharge the clean gas from
the gas discharge holes.
[0076] (4) In place of the holes 31, serving as gas diffusion
means, formed in the periphery of the inner wall 30, for changing
the gas flow centrally running from the combustion chamber 2 toward
the filtering member 4, the gas generator according to the present
invention may adopt the construction that a mountain-shaped baffle
plate opening to the filtering member 4 is provided in the inside
of the inner wall 30 and also the holes are formed at the corners
of the inner wall 30 on the filtering member 4 side. This type of
baffle plate enables the gas flow to change from the axial
direction to the circumferential direction of the inner wall 30. As
a result of this, the gas can be discharged from the holes formed
at the corners of the inner wall 30 on the filtering member 4 side
to diffuse the gas flow.
[0077] (5) The housing 1 need not necessarily be an elongated
cylinder shape. The housing 1 may have any suitable shape in
section, such as an elliptical shape and a rectangular shape, so
that it can be housed in the buckle of the seatbelt.
[0078] (6) The gas discharge tube 40 need not necessarily be
coaxial or parallel with the axis of the outer cylinder S. The gas
discharge tube 40 may be inclined at any adequate angle.
[0079] CAPABILITY OF EXPLOITATION IN INDUSTRY
[0080] According to the gas generator of the present invention, the
clean gas generated in the housing 1 can be introduced into the
elongated hollow seatbelt of the air-belt directly. This can
produce the result that the seatbelt of the air-belt can be
inflated instantaneously. This can also produce the result that the
gas generator can be reduced in size.
* * * * *