U.S. patent application number 10/169100 was filed with the patent office on 2002-12-19 for gas generator.
Invention is credited to Amano, Junya, Ikeda, Kenjiro, Kubo, Dairi, Maeda, Shigeru, Maruyama, Junya.
Application Number | 20020189487 10/169100 |
Document ID | / |
Family ID | 26583342 |
Filed Date | 2002-12-19 |
United States Patent
Application |
20020189487 |
Kind Code |
A1 |
Kubo, Dairi ; et
al. |
December 19, 2002 |
Gas generator
Abstract
A gas generator includes a first cup 10 packed with gas
generating agent 14 that generates gas by burning; a second cup E
disposed in an inside of the first cup 10 and containing ignition
agent; and a holder 9 holding the first cup 10 thereon and also
holding a plug B of the second cup E or the second cup thereon. In
the gas generator, there is provided a separator 15 which allows
the gas generating agent 14 to be confined within the first cup 10
so as to shield the gas generating agent from the second cup E.
Further, the separator 15 is so disposed as to cover the second cup
E. In addition, seal materials, such as an O-ring 16, is arranged
in a moisture inflow path through which moisture or equivalent
comes in from outside of the gas generator 18.
Inventors: |
Kubo, Dairi; (Himeji-shi,
JP) ; Amano, Junya; (Himeji-shi, JP) ;
Maruyama, Junya; (Kabushiki-Kaisha, JP) ; Maeda,
Shigeru; (Toyotomi-cho, JP) ; Ikeda, Kenjiro;
(Himeji-shi, JP) |
Correspondence
Address: |
OBLON SPIVAK MCCLELLAND MAIER & NEUSTADT PC
FOURTH FLOOR
1755 JEFFERSON DAVIS HIGHWAY
ARLINGTON
VA
22202
US
|
Family ID: |
26583342 |
Appl. No.: |
10/169100 |
Filed: |
July 12, 2002 |
PCT Filed: |
January 12, 2001 |
PCT NO: |
PCT/JP01/00106 |
Current U.S.
Class: |
102/530 |
Current CPC
Class: |
F42B 3/103 20130101;
B60R 22/4628 20130101; B60R 21/2644 20130101; C06D 5/06 20130101;
B60R 2021/26029 20130101 |
Class at
Publication: |
102/530 |
International
Class: |
C06D 005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 12, 2000 |
JP |
2000-3115 |
Oct 27, 2000 |
JP |
2000-327952 |
Claims
1. A gas generator comprising a first cup packed with gas
generating agent that generates gas by burning; a second cup
disposed in an inside of the first cup and containing ignition
agent; and a holder holding the first cup and a plug for the second
cup or holding the first cup and the second cup wherein there is
provided a separator which allows the gas generating agent to be
confined within the first cup so as to shield the gas generating
agent from the second cup.
2. The gas generator according to claim 1, wherein the separator is
disposed so as to cover the second cup.
3. The gas generator according to claim 1 or 2, wherein the
separator is disposed so that at least a part of an outside surface
of the separator can be contacted with an inside face of the first
cup.
4. The gas generator according to claim 1 or 2, wherein the
separator is set in position within the fist cup by a protrusion or
a step provided in the inside surface of the first cup.
5. The gas generator according to claim 1 or 2, wherein the
separator is held onto the holder by crimping.
6. The gas generator according to claim 1 or 2, wherein seal
materials for sealing a gap between the separator and the first cup
is disposed therebetween.
7. The gas generator according to claim 1 or 2, wherein the
separator is held on the holder, together with the plug of the
second cup, by crimping.
8. The gas generator according to claim 1 or 2, wherein seal
materials for sealing a gap between the separator and the holder is
disposed therebetween.
9. The gas generator according to claim 1 or 2, wherein the holder
is made of metal, and seal materials for sealing a gap between the
separator and the holder and a gap between the first cup and the
holder are respectively disposed.
10. The gas generator according to claim 1 or 2, wherein the holder
and the plug are integrally formed.
11. The gas generator according to claim 1 or 2, wherein the
separator has a score on itself.
12. The gas generator according to claim 1 or 2, wherein the gas
generating agent comprises nitrogen-containing organic compound as
fuel component, inorganic compound as oxidizing agent component and
at least one additive.
13. The gas generator according to claim 12, wherein the gas
generating agent comprises at least one material selected from the
group consisting of 5-aminotetrazole, guanidine nitrate and
nitroguanidine as the fuel component; and at least one material
selected from the group consisting of strontium nitrate, ammonium
nitrate, potassium nitrate, ammonium perchlorate and potassium
perchlorate as the oxidizing agent component
14. The gas generator according to claim 12, wherein the gas
generating agent comprises molybdenum trioxide as the additive.
15. The gas generator according to claim 12, wherein the additive
of the gas generating agent comprises at least one material
selected from the group consisting of cyamoposis gum, methyl
cellulose, carboxymethyl cellulose, water-soluble cellulose ether
and polyethylene glycol.
16. The gas generator according to claim 12, wherein the gas
generating agent comprises 5-aminotetrazole and guanidine nitrate
as the fuel component; strontium nitrate and ammonium perchorate as
the oxidizing agent component; molybdenum trioxide and cyamoposis
gum as the additive.
17. The gas generator according to claim 12, wherein the gas
generating agent comprises 10-30 mass percent of 5-aminotetrazole
and 15-35 mass percent of guanidine nitrate as the fuel component;
10-30 mass percent of strontium nitrate and 15-35 mass percent of
ammonium perchlorate as the oxidizing agent component; and 1-10
mass percent of molybdenum trioxide and 1-10 mass percent of
cyamoposis gum as the additive.
18. The gas generator according to claim 1 or 2, which is used for
a seatbelt pretensioner.
Description
TECHNICAL FIELD
[0001] The present invention relates to a compact gas generator
mainly used for operating a seatbelt pretensioner of an
automobile.
BACKGROUND ART
[0002] A seatbelt pretensioner is known as an occupant restraint
system for protecting occupants in an automobile from an automobile
collision shock. The pretensioner operates to actuate a cylinder by
a large quantity of high temperature and high pressure gas
generated from a gas generator. Since the gas generator operates to
actuate the cylinder, not an airbag, the gas generator requires a
relatively small quantity of generated gas and is so structured as
to erupt the high temperature and high pressure gas directly into
the cylinder without any mediation such as a filter or a coolant.
In general, the gas generator comprises an igniter that contains
ignition agents to be ignited when electric power is applied, a
first cup that contains gas generating agents, and a holder for
fixing the squib and the first cup and is relative simple in
structure.
[0003] One example of a conventional gas generator for seatbelt
pretentioner is shown in FIG. 9. The gas generator 108 of FIG. 9
comprises gas generating agents 106 that generate a large quantity
of gas by ignition, an igniter 104 that contains ignition agents to
be ignited by the application of electric power, a first cup 102
for containing the gas generating agents, a holder 101 for fixing
the igniter 104 and the first cup 102 in tie center thereof to seal
the gas generating agents 106 and the igniter 104 in the inside of
the first cup 102, an O-ring 10S, disposed in a gap between the
igniter 104 and the holder 101, for preventing moisture from coming
in through the gap therebetween, and a shorting dip 107 for keeping
two pins A vertically projecting from the igniter 104 in their
shorted state. Sealing material, not shown, is applied to the gap
between the first cup 102 and the holder 101 to prevent moisture
from coming in through the gap.
[0004] The igniter 104 comprises, in general, a second cup B that
contains ignition agent D, a plug B inserted in the second cup E to
be fitted therein to seal off the ignition agent D, and the two
pins A comprising metal rods extending through the plug B, as shown
in FIG. 8. The pins A project into the second cup E and are
electrically connected with each other at front ends thereof by a
bridge wire F bridging therebetween. The bridge wire F is covered
with an ignitable agent C contacting with the ignition agent D.
[0005] In general, there is the possibility that the gas generating
agents contained in the gas generator may change in combustion
pattern from the initially designed one due to moisture absorption.
In view of his, the conventional seatbelt pretensioner has mainly
used smokeless powder as the gas generating agents 106. The
smokeless powder is not high in moisture-absorption characteristics
and the gas generator has not been required to have high
moisture-absorption characteristics so far.
[0006] However, it is being required that a variety of gas
generating agents are used for designing the combustion pattern
variously. Under the circumstances, when the gas generating agents
having high moisture-absorption characteristic are used, the gas
generator having high moisture-proof characteristics is
required.
[0007] In the conventional gas generator, there is the possibility
that moisture, damp and the like may come into the gas generator
from outside of the gas generator through two inflow paths, i.e., a
gap between the first cup 102 and the holder 101 and a gap between
the igniter 102 and the holder 101. To keep moisture proof, both of
the two inflow paths must be designed and manufactured precisely.
As a practical matter, the conventional gas generator uses sealant,
such as the O-ring 105, for the two inflow paths, to prevent the
gas generating agents 106 from absorbing moisture.
[0008] In the conventional gas generator, the igniter is held in
the exposed state in the first cup. From viewpoints of costs and
assembling workability of the igniter, the second cup of the
igniter is sometimes formed of resin of low material strength and
the like material.
[0009] In general, explosives, such as ignition agents, have the
property of burning at an increased burning velocity under high
pressure. In the case where the second cup of the igniter is formed
of resin of low material strength and the like material, even when
the ignition agent of the igniter is ignited, the second cup is
broken before the pressure rises up to high pressure at the burning
of the ignition agent and, as a result, the burning velocity is
decreased. The time required for the igniter to be ignited is
usually of the order of 2 milliseconds (ms). Depending on the
circumstances, it sometimes takes more time than that to ignite the
igniter.
[0010] In general, the gas generator is required to be worked
within 2 milliseconds (ms). If the operation of the gas generator
delays any more, there is the possibility that the gas generator
cannot fully exhibit its performance.
[0011] It is the object of the present invention to suppress
moisture absorption of the gas generating agents in the gas
generator and also shorten the time required for the igniter to be
ignited, thereby providing a gas generator that is less subject to
atmospheric moisture, operates without time delay, and exhibits
its-performance fully for a seatbelt pretensioner and the like
system.
DISCLOSURE OF THE INVENTION
[0012] The present invention relates to a gas generator comprising
a first cup packed with gas generating agent that generates gas by
burning; a second cup disposed in an inside of the first cup and
containing ignition agent; and a holder holding the first cup and
also holding thereon a plug holding the second cup thereon or the
second cup.
[0013] The present invention is characterized in that there is
provided a separator which allows the gas generating agent to be
confined within the first cup so as to shield the gas generating
agent from the second cup.
[0014] The purpose of shielding the gas generating agent from the
second cup by the separator is to prevent moisture such as damp
from coming into the first cup from outside of the gas generator
through the plug of the second cup and others.
[0015] Accordingly, as long as the shield is effected to the extent
that the moisture proof is substantially kept, tight seal is not
necessarily required. Conversely, even when the tight seat is
provided by the separator, if the separator itself has moisture
permeability, there is the possibility that the moisture proof may
not be kept. Accordingly, the separator is preferably made of
material of low moisture permeability. Although the separator is
not necessarily formed by a single member but may be formed by
combination of several parts, it is preferable that the separator
is formed by a single member from the viewpoint of reduction of
parts count. It is also preferable that the separator has no
through hole piercing in and out.
[0016] Thus, the gas generator of the present invention enables
moisture flowing toward the gas generating agent to be reduced
significantly by using the separator. As a result of this, even
when the gas generating agent comprising nitrogen-containing
organic compound, mentioned later, is used, the gas generating
agent absorbs less moisture and, as a result of this, slower
burning velocity of the gas generating agent, in other words,
degrading the performance of the gas generator is prevented.
[0017] In the gas generator of the present invention, it is
preferable that the separator is disposed so as to cover the second
cup.
[0018] When the ignition agent in the second cup of the igniter is
ignited, the separator prevents the second cup of the igniter from
being broken before the internal pressure rises up to high pressure
at the time of burning of the ignition agent. Accordingly, the
ignition agent is burnt under high pressure. As a result of this,
the burning velocity is increased, as compared with conventional,
so that the ignition time delay of the gas generator 18 is
reduced.
[0019] In the sense of preventing the second cup of the igniter
from being broken before the pressure rises up to high pressure at
the time of burning of the ignition agent, it is preferable that
the material used for the separator has the property of high
strength, in addition to the property of low moisture permeability,
as mentioned above. The materials of the separator that may be used
include metals, such as iron, aluminum and stainless steel, and
resins, such as PBT and fluorocarbon resin. Also, as long as the
second cup of the igniter is prevented from being broken before the
pressure rises up to high pressure at the time of burning of the
ignition agent, the separator need not cover the entire area of the
second cup, but preferably it covers the second cup almost
entirely. Also, the gap between the separator and the second cup is
preferably 1 mm or less, or further preferably, 0.2 mm or less.
[0020] As mentioned above, the separator can provide the two
combined results of preventing the inflow of moisture and reducing
the ignition time delay. Hence, desired performance can be obtained
with a reduced component count, as compared with the case where the
required parts are added one for each intended purpose.
[0021] Further, in the gas generator of the present invention, it
is preferable that the separator is disposed so that at least a
part of an outside surface of the separator can be contacted with
an inside surface around the first cup. As a result of this
structure, the inflow path from an outside of the gas generator
into the interior of the first cup is limited to a single path that
pass through the gap between a contact surface of the separator and
a contact surface of the first cup.
[0022] In the gas generator of the present invention, it is
preferable that the first cup is provided with a protrusion or a
step in an inside surface thereof and the separator is held in its
position by the protrusion or the step provided in the inside
surface of the first cup.
[0023] In the gas generator of the present invention, it is
preferable that the separator is held onto the holder by
crimping.
[0024] As a result of the separator being held on the holder by
crimping or held in its position by the protrusion or the step
provided in the inside surface of the first cup, the separator can
be easily set in position within the first cup in the manufacturing
process. Also, as a result of the separator being held on the
holder by crimping or held in position by the protrusion or step of
the first cup, when the gas generator is operated, the separator is
prevented from flying out of the gas generator in all directions.
In addition, when the ignition agent in the igniter is ignited, the
separator can be prevented from being out of position.
[0025] Further, it is preferable that seal materials for sealing a
gap between the separator and the holder is disposed therebetween.
In addition, in the gas generator of the present invention, it is
preferable that seal materials for sealing a gap between the
separator and the first cup is disposed therebetween.
[0026] To be more specific, an annular groove for fitting the seal
materials therein is formed around the contact surface between the
separator and the first cup. The seal materials, such as O-ring, is
set in the groove, while keeping its elasticity between the
separator and the first cup. Also, an engaging portion is provided
between the separator and the holder and also the seal materials,
such as a sheet packing, or sealant is disposed therebetween so as
to contact with both of them.
[0027] The provision of the seal materials or the sealant can
further effectively prevent the moisture, such as damp, and air
from coming into the first cup from the outside of the gas
generator through the path communicating therebetween.
[0028] In addition, when the separator is disposed in the gas
generator of low moisture permeability, the igniter itself
comprising the second cup or the plug of the second cup can also
completely shut off the inflow moisture from the gas generating
agent.
[0029] Further, in the gas generator of the present invention, it
is preferable that the separator is held on the holder, together
with the plug of the second cup, by crimping. In this case, the
separator and/or the holder are preferably made of metal.
[0030] The gas generator having the construction wherein the
separator is held on the holder, together with the plug of the
second cup, by crimping can provide the result that changes in
design and in assembling process that are caused by the provision
of the separator can be lessened, as compared with the conventional
gas generator comprising no separator.
[0031] Further, in the case where the holder is made of metal and
is an airtight holder itself and also the first cup and the
separator are fixed to the holder in different places by crimping
and the like, it is preferable that the sheet packing or sealant is
provided between the separator and the holder as well as between
the first cup and the holder. This can prevent the moisture, such
as damp, and air from coming into the first cup from the outside of
the gas generator through the pass communicating therebetween
further effectively.
[0032] No particular limitation is imposed on the seal materials,
as long as they are commonly used as the seal materials.
Preferably, the materials of hard water permeable ox low moisture
permeability, such as nitrile rubber, silicon rubber, and ethylene
propylene rubber, may be used. The adhesives, such as epoxy resin,
may alternatively be applied Also, as long as the seal materials
have the form to closely contact with the contact surface and close
up the gap, any form may be used, including an O-ring form and a
sheet form.
[0033] In the gas generator of the present invention, the holder
and the plug of the second cup may be integrally formed. As a
result of this construction, the gap between the holder and the
plug of the second cup, in other words, the moisture or air inflow
path therebetween goes out of existence. As a result of this, the
number of paths communicating from the outside of the gas generator
into the first cup is reduced and, therefore, the moisture, such as
damp, and air coming into the first cup can be shut off further
effectively.
[0034] Further, in the present invention, the separator is provided
with a score, which is one characteristic feature of the invention.
As a result of this construction, the score of the separator, after
broken by the high temperature and high pressure gas and particles
caused by the ignition of the igniter, can allow the high
temperature and high pressure gas and particles to be concentrated
to only the direction toward the gas generating agents. Thus, the
score provided in the separator is preferable oriented toward the
gas generating agents, The provision of the score can also provide
the advantage that when the separator is fractured by the igniter,
the fractions can be prevented from flying in all directions.
[0035] The gas generator of the present invention that is capable
of keeping the moisture proof as mentioned above is suitable for
use with the gas generating agent comprising nitrogen-containing
organic compound as fuel component.
[0036] The gas generating agents that may be used for the gas
generator of the present invention include gas generating agent
comprising nitrogen-containing organic compound as fuel component,
inorganic compound as oxidizing agent component and at least one
additive. The gas generating agent having the composition mentioned
above could become a gas generating agent having the burning
characteristics suitable for the seatbelt pretensioner.
[0037] Accordingly, the gas generator of the present invention is
suitable for the gas generator for seatbelt pretensioner.
[0038] Preferably, the gas generating agent comprises molybdenum
trioxide which is an autoignition catalyst as an additive. As a
result of the gas generating agent containing molybdenum trioxide,
the gas generating agent has an automatic ignition capability The
terminology "automatic ignition capability" used here means the gas
generating agent in the gas generator having the property of being
ignited and burnt within one minute at a temperature of 200.degree.
C.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] FIG. 1 is a schematic sectional view of the first embodiment
of gas generator according to the present invention;
[0040] FIG. 2 is a schematic sectional view of the second
embodiment of gas generator according to the present invention;
[0041] FIG. 3 is a schematic sectional view of the third embodiment
of gas generator according to the present invention;
[0042] FIG. 4 is a schematic sectional view of the fourth
embodiment of gas generator according to the present invention;
[0043] FIG. 5 is a schematic sectional view of the fifth embodiment
of gas generator according to the present invention;
[0044] FIG. 6 is a schematic sectional view of the sixth embodiment
of gas generator according to the present invention;
[0045] FIG. 7 is a schematic sectional view of the seventh
embodiment of gas generator according to the present invention;
[0046] FIG. 8 is a schematic sectional view of an igniter of the
gas generator;
[0047] FIG. 9 is a schematic sectional view of one example of a
general type of gas generator; and
[0048] FIG. 10 is a table showing the test results.
BEST MODE FOR CARRYING OUT THE INVENTION
[0049] In the following, certain preferred embodiments of the
present invention will be described with reference to FIGS. 1
through 7.
First Embodiment
[0050] First, the first embodiment of the present invention will be
described below. A gas generator 18 shown in FIG. 1 is designed for
actuating a seatbelt pretensioner of an automobile. The gas
generator 18 bums gas generating agents 14 by ignition of an
igniter 12 to thereby generate an adequate quantity of gas rapidly.
As a result of this, the seatbelt pretensioner, not shown, is
actuated.
[0051] In FIG. 1, the gas generator 18 comprises a first cup 10,
the gas generating agents 14, the igniter 12, a holder 9 and a
separator 15.
[0052] The first cup 10 is packed with the gas generating agents 14
in the condition that the gas generating agents are in direct
contact with an inside surface around the first cup without
mediation of a filter and/or a coolant.
[0053] The first cup 10 has a large diameter cylindrical portion
10a and a small diameter cylindrical portion 10b and has
substantially a bottomed cylindrical form that is increased in
diameter in a single stage from the bottom. The first cup 10 has a
step 29 formed around the inside surface at the joining portion of
the large diameter cylindrical portion and the small diameter
cylindrical portion. Also, the first cup 10 has a plurality of
linear notches 10c in the bottom.
[0054] When the gas generating agents 14 contained in the first cup
10 are burnt, the notches 10c are broken, so that the gas is
discharged directly to a seatbelt pretensioner, not shown. The
first cup 10 has a radially outwardly extended, flanged portion 10d
formed at an opening end thereof and the flanged portion 10d is
fixed to the holder 9 by crimping, Materials of the first cup 10
that may be used include metals such as stainless steel and
aluminum.
[0055] The igniter 12 includes, as shown in FIG. 8, ignition agent
D, a second cup E for the ignition agent D to be packed therein,
two vertically projected pins A for passing electric power through
them to ignite the ignition agent D, and a plug B.
[0056] A shorting clip 11 for shorting the two pins A is attached
to the igniter 12, as shown in FIG. 1. The shorting clip 11 serves
to prevent an improper operation caused by static electricity.
[0057] In FIG. 1, the holder 9 is formed of metal such as stainless
steel and aluminum or resin. The holder 9 has a first hole 9c for
the plug B of the igniter 12 to be inserted and fitted therein, a
projection 9b for crimping the plug B of the igniter 12, and a
projection 9a for crimping the first cup 10. The holder 9 fixes the
position of the first cup 10 so that the igniter 12 can be
positioned in the center of the first cup 10 and also holds the
plug B of the igniter 12. An O-ring 13 is disposed in a gap between
the igniter 12 and the holder 9.
[0058] The separator 15 covers the second cup of the igniter 12,
with its outside surface contacting with the inside surface of the
first cup 10. The separator 15 in the first cup 10 is positioned by
the step 29 formed in the inside of the cylindrical portion of the
first cup 10. The materials of the separator 15 that may be used
include metals, such as iron, aluminum and stainless steel, and
resins, such as PBT and fluorocarbon resin. The separator 15 is
substantially in the form of a short-length cylindrical member. The
separator 15 has a score 17 and a second hole 15a. The separator 15
serves as a plug of the first cup packed with the gas generating
agents and shields the igniter and the gas generating agents from
each other within the fist cup.
[0059] The score 17 is provided at the gas generating agents 14
side, in order to concentrate the energy of the igniter 12 to the
gas generating agents 14. Preferably, the score 17 is arranged to
such an extent as not to pierce the separator 15, though it may be
arranged in such a manner that after the score 17 pierces the
separator 15, the separator 15 thus pierced is dosed by e.g.
aluminum foil.
[0060] The second hole 15a is a hole for the second cup E of the
igniter 12 to be inserted and fitted therein. Preferably, the
second hole 15a has an inside surface corresponding in form to an
outside surface of the second cup E of the igniter 12 so that the
second cup E of the igniter 12 and the separator 15 can be
substantially closely contacted with each other. The gap between
the second cup E and the separator 15 is preferably 1 mm or less,
or further preferably, 0.2 mm or less. When the gap therebetween is
within this range, no problem is presented.
[0061] Preferably, the contact surface of the separator 15 and the
contact surface of the fist cup 10 are brought into close contact
with each other. Even if the contact surfaces are not closely
contacted with each other, the moisture inflowing path can be
limited to the single gap between the first cup 10 and the
separator 15. In contrast to this, there are, in general, provided
two moisture inflow paths, i.e., the gap between the first cup 102
and the holder 101 and the gap between the igniter 102 and the
holder 101 (See FIG. 9).
[0062] Further, the separator 15 may have seal materials, such as
an O-ring 16, on its surface contacting with the first cup 10 of
the separator 15, to further ensure the moisture-proof
property.
[0063] The O-ring 16 of the seal materials is set in a groove 15b
circularly formed around the outside surface of the separator 15
contacting with inside surface of the first cup 10. The O-ring 16
is set between the separator 15 and the first cup 10, while keeping
its elasticity, and forming a part of the separator 15.
[0064] As a result of this structure, the moisture coming into the
gas generating agents is guided into a singly limited path in the
contact surface between the separator 15 and the first cup 10. In
addition to this, the O-ring 16 for sealing the gap between the
separator 15 and the first cup 10 is set in that path. Also, since
the separator 15 is placed in such a manner as to cover the second
cup E of the igniter 12 and also the score 17 is machined in the
direction of the gas generating agents 14, the energy of the
igniter 12 is concentrated to the direction of the gas generating
agents 14. Additionally, since the second cup E of the igniter 12
is covered with the separator 15, the strength is enhanced.
[0065] Consequently, when the ignition agent in the interior of the
igniter 12 is ignited and burnt, the second cup E is prevented from
being broken before the internal pressure of the igniter 12 rises
up to high pressure, so that the ignition agent is burnt under high
pressure. As a result of this, the burning velocity is increased,
as compared with the prior art, and the ignition time delay of the
gas generator 18 is reduced.
[0066] The gas generator 18 thus constructed can be produced in the
following order. A prescribed amount of gas generating agent 14 is
packed in the first cup 10 having the step 29. The O-ring 16 is set
in the groove 15b formed in the separator 15. The separator 15 is
inserted in the first cup 10 packed with the gas generating agents
14 deep to the step 29 and is fitted therein. The first cup 10
packed with the gas generating agents 14 is produced in this
order.
[0067] As the moisture-proof against the gas generating agents 14
is secured in this state, the first cup 10 may be separately
produced and stored as a component for producing the gas generator
just as it is. Further, no strict moisture regulation of
manufactory is required in the producing processes subsequent to
the process of inserting the separator 15 in the first cup 10. As a
result of this, manufacturing costs can be reduced.
[0068] Then, after the igniter 12 is inserted in the holder 9, the
projection 9b of the holder 9 is crimped toward the igniter 12, to
fix the igniter 12 to the holder 9. At this stage, the O-ring 13 is
set between the holder 9 and the igniter 12, while keeping its
elasticity.
[0069] Then, the holder 9 to which the igniter 12 is fixed is
fitted in the first cup 10 in which the gas generating agents 14
are contained, The projection 9a of the holder 9 is bent over the
flanged portion 10d formed at an opening end of the first cup 10
and is crimped, whereby the first cup 10 and the holder 9 are
integrally combined with each other.
[0070] Then, operation of the gas generator 18 will be described.
When a collision sensor, not show, detects a car collision, the
vertically projecting pins A in the igniter 12 shown in FIG. 8 are
electrically energized. Then, the bridge wire F in the igniter 12
generates heat to ignite the ignitable agent C. Sequentially, as a
result of the ignition of the ignitable agent C, the ignition agent
D is ignited and burnt. Although along with the burning of the
ignition agent D, the interior of the igniter 12 increases in
temperature and pressure, since the second cup E of the igniter 12
is covered with the separator 15 and thus is reinforced, as shown
in FIG. 1, the igniter 12 is prevented from being expanded and
broken until the ignition agent D is fully burnt.
[0071] As the pressure rises up, the burning velocity of the
explosives used for the ignition agent D increases. Accordingly,
the igniter 12 is eventually broken earlier, as compared with the
igniter that is not covered with the separator 15. After the
burning proceeds further, the gas and particles fully increased in
temperature and pressure are released toward the separator 15. At
this time, the released gas and particles fracture the score 17 of
the separator 15. Then, passing through the fractured score, the
high temperature and high pressure gas and particles are sprayed at
a burst onto the gas generating agents 14 packed in the first cup
10. Then, the gas generating agents 14 are ignited. The separator
15 is held by the step 29, so that it is prevented from being blown
out toward the gas generating agents 14.
[0072] Sequentially, a large amount of gas generated in the first
cup 10 by the burning of the gas generating agents 14 causes the
interior pressure of the first cup 10 to rise up rapidly and then
causes the notches 10c provided in the bottom of the first cup 10
to be fractured. Then, the large amount of gas is introduced into
the seatbelt pretensioner, not shown, to actuate the seatbelt
pretensioner.
Second Embodiment
[0073] Next, the second embodiment of the gas generator of the
present invention will be described. It is to be noted that the
members in FIG. 2 identical in function to those in FIG. 1 are
given like reference characters, to avoid redundancy of
explanation.
[0074] The gas generator 23 shown in FIG. 2 has a first cup 21
having an inwardly projecting protrusion 30 in an inside surface
thereof.
[0075] The first cup 21 has a large diameter cylindrical portion
21a and a small diameter cylindrical portion 21b and has
substantially a bottomed cylindrical form that is increased in
diameter in a single stage from the bottom. The first cup has the
step 29 formed around the inside surface in the boundary between
the large diameter cylindrical portion and the small diameter
cylindrical portion. Also, the first cup 21 has a plurality of
linear notches 2c in the bottom. When the gas generating agents 14
contained in the first cup 21 are burnt, the notches 21c are
broken, so that the gas is discharged directly to the seatbelt
pretensioner, not shown. The first cup 21 has a radially outwardly
extended, flanged portion 21d formed at an opening end thereof, and
the flanged portion 21d is fixed to the holder 9 by crimping.
Materials of the first cup 21 that may be used include metals such
as stainless steel and aluminum.
[0076] The inwardly projecting protrusion 30 formed around the
inside surface of the first cup 21 is out of position toward the
opening end of the first cup 21, as compared with the step 29 of
the gas generator 18 shown in FIG. 1. The other side of the
protrusion 30 is a recessed portion, when viewed from the outside
surface of the first cup 21.
[0077] The protrusion 30 is additionally provided for allowing the
separator 19 to be positioned when the step 29 must be provided in
a limited place from the mounting relation with respect to the
seatbelt pretensioner.
[0078] This can allow the separator 19 to be positioned while
keeping the volume of the interior of the first cup 21 larger than
that of the first cup 21 shown in FIG. 1.
[0079] The protrusion 30 is provided around the inside surface of
the first cup 21 at a location corresponding to around a central
portion with respect to height of the second cup E of the igniter
12.
[0080] The separator 19 to be positioned by the protrusion 30 is
formed to protrude toward the gas generating agents 14, so that its
axial part 19a covers the second cup E of the igniter 12 with it. A
part of the outside surface of the separator 19, specifically at
the opening side, is set to have a diameter to contact with the
inside surface of the large diameter cylindrical portion 21a of the
first cup. The separator serves as the plug of the first cup packed
with the gas generating agents and shields the igniter and the gas
generating agents from each other within the first cup.
[0081] Although the gas generator 23, in which the protrusion 30 is
provided in advance in the first cup 21 before the separator 19 is
fitted in the first cup 21, has been illustrated above,
modification may be made such that after the separator 19 is fitted
in the first cup 21, the first cup 21 is crimped from outside to
form the recessed portion in the outside surface, whereby the
protrusion 30 is formed around the inside surface to fix the
separator 19 in the first cup. Alternatively, the corresponding
portion of the first cup 21 may be crimped from outside so that the
protrusion 30 may be formed toward the O-ring groove 19b of the
separator 19 in which the O-ring 16 is set.
Third Embodiment
[0082] Next, the third embodiment of the gas generator of the
present invention will be described. It is to be noted that the
members in FIG. 3 identical in function to those in FIG. 1 are
given like reference characters, to avoid redundancy of
explanation.
[0083] The gas generator 28 shown in FIG. 3 has a cup-shaped
separator 24. The cup-shaped separator 24 is mounted on the holder
26, together with the first cup 10, by crimping.
[0084] The holder 26 has a crimping projection 26a for mounting
both of the first cup 10 and the separator 24 on the holder 26.
[0085] The separator 24 is formed in a cup-like shape to cover the
igniter 12 with it and is mounted on the holder 26. A part of the
outside surface of the separator 24, specifically at the opening
side, is set to have a diameter to contact with the inside surface
of the large diameter cylindrical portion 10a of the first cup or
slightly smaller than that. The separator serves as the plug of the
first cup packed with the gas generating agents and shields the
igniter and the gas generating agents from each other within the
first cup.
[0086] The separator 24 has a radially outwardly extended, flanged
portion 24a formed at an opening end thereof, so that the separator
24 and the first cup 10 can both be mounted on the holder 26.
[0087] The flanged portion 24a and the flanged portion 10b of the
first cup 10 packed with the gas generating agents 14 are both
mounted on the holder 26. The mounting portion is crimped by
weighing down the crimping projection 26a of the holder 26 onto the
flanged portion 10d of the first cup 10. A seat packing 25 of seal
materials is set between the flanged portion 10d of the first cup
10 and the flanged portion 24a of the separator 24, while keeping
its elasticity. The score 27 is provided at the gas generating
agents 14 side of the separator 24.
[0088] The igniter 12 is fitted in the first hole 26b of the holder
26 by the separator 24, instead of being mounted directly on the
holder 26 by crimping. The O-ring 13 is set between the holder 26
and the igniter 12, while keeping its elasticity.
Fourth Embodiment
[0089] Next, the fourth embodiment of the gas generator of the
present invention will be described. It is to be noted that the
members in FIG. 4 identical in function to those in FIG. 1 are
given like reference characters, to avoid redundancy of
explanation.
[0090] The gas generator 34 shown in FIG. 4 has a cap-shaped
separator 32. The separator 32 is mounted on the holder 31 by
crimping.
[0091] The holder 31 has a crimping projection 31a for mounting the
first cup 10 thereon and a crimping projection 31b for mounting the
separator 32 and the plug B thereon.
[0092] The separator 32 is formed in a cup-like shape to cover the
second cup E of the igniter 12 and a front end of the plug B of the
igniter 12 with it. The separator has, at an opening end thereof, a
flanged portion 32a formed to obliquely extending radially
outwardly along the front end of the plug B so that it can be
mounted on the holder 31 by crimping. The flanged portion 32a is
mounted on the holder 31, together with the plug B of the igniter
12, by the projection 31b of the holder 81 crimped by folding the
projection 31b over the flanged portion 32a of the separator 32.
Sealing material, not shown, is applied to the gap between a
contact surface of the holder 31 and a contact surface of the
separator 32.
[0093] Then, the holder 31 mounting the igniter 12 and the
separator 32 thereon is inserted in the first cup 10 packed with
the gas generating agents 14, to be fitted therein. Then, the first
cup 10 is mounted on the holder 31 by the projection 31a of the
holder 31 crimped by folding the projection 31a over the flanged
portion 10d of the first cup 10.
[0094] An O-ring 33 of seal materials is set between the contact
surface of the holder 31 and the contact surface of the first cup
10, while keeping its elasticity.
[0095] The igniter 12 is fitted in the first hole 31c of the holder
31 by the separator 32, instead of being mounted directly on the
holder 31 by crimping. A sheet packing may be fitted in the gap,
instead of application of the sealant to the gap between the holder
31 and the separator 32.
[0096] The moisture trying to come into the first cup 10 along the
igniter 12 is blocked out by the holder 31 and the separator 32.
For providing further improved blockage of the moisture, it is
preferable from the viewpoints of strength and moisture
permeability that the holder 31 is formed of metals of strong and
low moisture permeability, such as stainless steel and aluminum.
Likewise, from the viewpoints of strength and moisture
permeability, it is preferable that the separator 32 is also formed
of metals of strong and low moisture permeability, such as
stainless steel and aluminum.
Fifth Embodiment
[0097] Next, the fifth embodiment of the gas generator of the
present invention will be described. It is to be noted that the
members in FIG. 5 identical in function to those in FIG. 1 are
given like reference characters, to avoid redundancy of
explanation.
[0098] The gas generator 43 of FIG. 5 has the structure that the
holder 35 and the plug B of the igniter 38 are integrally formed of
resin.
[0099] The first cup 36 has a large diameter cylindrical portion
36a, an intermediate diameter cylindrical portion 36b and a small
diameter cylindrical portion 36c and has substantially a bottomed
cylindrical form that is increased in diameter in two stages from
the bottom. The first cup has two steps 41a, 41b which are formed
around the inside surfaces in the boundaries between the large
diameter cylindrical portion and the intermediate diameter
cylindrical portion and between the intermediate diameter
cylindrical portion and the small diameter cylindrical portion,
respectively.
[0100] The separator 37 is formed in a cup-like shape to cover the
igniter 38 with it and is mounted on the holder 35. A part of the
outside surface of the separator 37, specifically at the opening
side, is set to have a diameter to contact with the inside surface
of the intermediate diameter cylindrical portion 86b of the first
cup or slightly smaller than that. The separator serves as the plug
of the first cup packed with the gas generating agents and shields
the igniter and the gas generating agents from each other within
the first cup. The separator 37 has, at an opening end thereof, a
flanged portion 37a formed to project to an inside surface of the
large diameter cylindrical portion 36a of the first cup. The
separator 37 is set in position in the first cup 86 by the flanged
portion 37a being abutted with the step 41a at the opening side of
the first cup 36.
[0101] The holder 35 includes an integrally formed metal insert 42.
The insert 42 comprises a cylindrical member 42b and a ring-shaped
plate 42a continuously extending from one end of the cylindrical
member 42b and forms a flange projecting from the holder 35.
[0102] The flanged portion 37a of the separator 37 is brought into
abutment with the step 41a of the first cup 36, first, and, then,
the ring-shaped plate 42a of the metal insert 42 is brought into
abutment with the flanged portion 37a through the O-ring 39. In
this state, the opening end of the first cup 36 is folded over the
other end of the cylindrical member 42b of the metal insert 42 and
is crimped so that the flanged portion 37a of the separator 37, the
metal insert 42, and the first cup 36 can be integrally combined
with each other.
[0103] At this time, the step 41a of the first cup 36 and the
flanged portion 37a of the separator 37 are pressed toward the
metal insert 42, so that the O-ring 39 is deformed to close up the
gaps therebetween. The separator 37 has the score 40 formed at a
portion thereof on the gas generating agents 14 side.
Sixth Embodiment
[0104] Next, the sixth embodiment of the gas generator of the
present invention will be described. The gas generator 47 of FIG. 6
has the structure that the holder 44 and the plug B of the igniter
38 are integrally formed of resin. It is to be noted that the
members in FIG. 6 identical in function to those in FIG. 1 are
given like reference characters, to avoid redundancy of
explanation.
[0105] The first cup 45 has a large diameter cylindrical portion
45a, an intermediate diameter cylindrical portion 45b and a small
diameter cylindrical portion 45c and has a bottomed cylindrical
form that is increased in diameter in two stages from the bottom.
The first cup has two steps 41a, 41b which are formed around the
inside surfaces in the boundaries between the large diameter
cylindrical portion and the intermediate diameter cylindrical
portion and between the intermediate diameter cylindrical portion
and the small diameter cylindrical portion, respectively.
[0106] The separator 37 is formed in a cup-like shape to cover the
igniter 38 with it and is mounted on the holder 44. A part of the
outside surface of the separator 37, specifically at the opening
side, is set to have a diameter to contact with the inside surface
of the intermediate diameter cylindrical portion 45b of the first
cup or slightly smaller than that. The separator serves as the plug
of the first cup packed with the gas generating agents and shields
the igniter and the gas generating agents from each other within
the first cup. The separator 37 has, at an opening end thereof, the
flanged portion 37a formed to project to an inside surface of the
large diameter cylindrical portion 45a of the first cup. The
separator 37 is set in position in the first cup 45 by the flanged
portion 37a being abutted with the step 41a at the opening side of
the first cup 45.
[0107] The holder 44 includes an integrally formed metal insert 46.
The insert 46 comprises a ring-shaped plate and forms a flange
projecting from the holder 44. The flanged portion 37a of the
separator 37 is brought into abutment with the step 41a of the fit
cup 45, first, and, then, one side of the metal insert 42 is
brought into abutment with the flanged portion 37a through the
O-ring 39. In this state, the opening end of the first cup 45 is
folded over the other side of the metal insert 42 and is crimped so
that the flanged portion 37a of the separator 37, the metal insert
42, and the first cup 45 can be integrally combined with each
other.
[0108] At this time, the step 41a of the first cup 45 and the
flanged portion 37a of the separator 37 are pressed toward the
metal insert 42, so that the O-ring 39 is deformed to dose up the
gaps therebetween. The separator 37 has the score 40 formed at a
portion thereof on the gas generating agents 14 side.
Seventh Embodiment
[0109] Next, the seventh embodiment of the gas generator of the
present invention will be described. It is to be noted that the
members in FIG. 7 identical in function to those in FIG. 1 are
given like reference characters, to avoid redundancy of
explanation.
[0110] The gas generator 49 of FIG. 7 has the structure that the
holder 48 and the plug B of the igniter 38 are integrally formed of
resin.
[0111] The first cup 36 has a large diameter cylindrical portion
36a, an intermediate diameter cylindrical portion 36b and a small
diameter cylindrical portion 36c and has a bottomed cylindrical
form that is increased in diameter in two stages from the bottom.
The first cup has two steps 41a, 41b which are formed around the
inside surfaces in the boundaries between the large diameter
cylindrical portion and the intermediate diameter cylindrical
portion and between the intermediate diameter cylindrical portion
and the small diameter cylindrical portion, respectively.
[0112] The separator 37 is formed in a cup-like shape to cover the
igniter 38 with it and is mounted on the holder 48. A part of the
outside surface of the separator 37, specifically at the opening
side, is set to have a diameter to contact with the inside surface
of the intermediate diameter cylindrical portion 86b of the first
cup or slightly smaller than that. The separator serves as the plug
of the first cup packed with the gas generating agents and shields
the igniter and the gas generating agents from each other within
the first cup. The separator 37 has, at an opening end thereof, the
flanged portion 37a formed to project to an inside surface of the
large diameter cylindrical portion 36a of the first cup. The
separator 37 is set in position in the first cup 36 by the flanged
portion 37a being abutted with the step 41a at the opening side of
the first cup 36.
[0113] The holder 48 includes an integrally combined metal insert
42. The insert 42 comprises a cylindrical member and forms a flange
projecting from the holder 48.
[0114] The flanged portion 37a of the separator 37 is brought into
abutment with the step 41a of the first cup 36, first, and, then,
one end of the metal insert 42 is brought into abutment with the
flanged portion 37a through the O-ring 39. In this state, the
opening end of the first cup 36 is folded over the other end of the
metal insert 42 and is crimped so that the flanged portion 37a of
the separator 37, the metal insert 42, and the first cup 36 can be
integrally combined with each other.
[0115] At this time, the step 41a of the first cup 36 and the
flanged portion 37a of the separator 37 are pressed toward the
metal insert 42, so that the O-ring 39 is deformed to close up the
gaps therebetween. The separator 37 has the score 40 formed at a
portion thereof on the gas generating agents 14 side.
Preferable Gas Generating Agent
[0116] Gas generating agent comprising nitrogen-containing organic
compound as fuel component, inorganic compound as oxidizing agent
component and at least one additive is preferable as the gas
generating agent used with the gas generator of the present
invention.
[0117] The fuel components that may be used include at least one
material selected from the group consisting of aminotetrazole,
guanidine nitrate, and nitroguidine. The oxidizing agent components
that may be used include at least one material selected from the
group consisting of strontium nitrate, ammonium nitrate, potassium
nitrate, ammonium perchlorate, and potassium perchlorate.
[0118] The additives that may be used include molybdenum trioxide
which is an autoignition catalyst.
[0119] Binder and equivalent can be cited as the other additive to
be added to the gas generating agent, The binders that may be used
include at least one material selected from the group consisting of
cyamoposis gum, methyl cellulose, carboxymethyl cellulose,
water-soluble cellulose ether and polyethylene glycol.
[0120] The gas generating agent comprises 5-aninotetrazole and
guanidine nitrate used as the fuel component; strontium nitrate and
ammonium perchorate used as the oxidizing agent component;
molybdenum trioxide used as the autoignition catalyst; and
cyamoposis gum used as the binder. Further preferably, the gas
generating agent comprises 10-30 mass percent of 5-aminotetrazole
and 15-35 mass percent of guanidine nitrate used as the fuel
component; 10-80 mass percent of strontium nitrate and 15-35 mass
percent of ammonium perchlorate used as the oxidizing agent
component; 1-10 mass percent of molybdenum trioxide used as the
autoignition catalyst; and 1-10 mass percent of cyamoposis gum used
as the binder.
Manufacturing Method of Gas Generating Agent
[0121] The manufacturing method of these gas generating agents will
be described. A prescribed amount of each of the components of the
gas generating agent is measured. After the measurement, the
components are fully stirred with a V-type stirring machine. 10-30
mass percent of water is added to the mixture and stirred further.
The wet mixture is kneaded with a kneader to produce a viscous
clot. This viscous dot is molded into a desired form with a vacuum
extruding machine. The extruded products are dried at 60.degree. C.
for 15 hours and then at 100.degree. C. for 5 hours to produce
desired gas generating agents.
EXAMPLES
[0122] In the following, further detailed description of the
present invention will be made with reference to Examples below. It
is to be noted that in the following examples and comparative
examples, the same igniter, gas generating agents and O-ring were
used.
Example 1
[0123] The gas generator as shown in FIG. 1 was produced. First,
the igniter was fixed to the aluminum holder through the O-ring.
Then, 0.9 g of gas generating agent, which comprises 19.0 mass
percent of 5-aminotetrazole, 26.0 mass percent of guanidine
nitrate, 22.0 mass percent of strontium nitrate, 26.0 mass percent
of ammonium perchlorate, 4.0 mass percent of molybdenum trioxide,
and 3.0 mass percent of cyamoposis gum, was measured and then was
packed in the first aluminum cup. The gas generating agents molded
into a single-hole cylindrical form each having an outer diameter
of .phi. 1.5 mm, an inner diameter of .phi. 0.5 mm, a height of 1.5
mm and a weight of 3 mg were used. Then, the separator, in which
the O-ring was fitted in the groove circularly formed around the
outside surface of a generally cylinder aluminum body, was inserted
in the first cup packed with the gas generating agents, so as to
contact with the inside surface of the first cup. Then, the
separator was set in position by the step of the first cup.
Finally, the holder in which the igniter was fixed was inserted in
the first cup and was fixed thereto by crimping.
[0124] The moisture absorption test was conducted by measuring a
quantity of moisture absorption of the gas generating agent after
the gas generator was kept at a temperature of 80.degree. C. and a
humidity of 95% and for 1,000 hours.
[0125] The measurement of the ignition time delay was made. The
start time of conducting electricity of electric power to the gas
generator was set at 0 and the time required for the pressure to
rise in a tank of an internal volume of 18 cc was measured as the
ignition time delay.
Example 2
[0126] The gas generator as shown in FIG. 2 was produced. First,
the igniter was fixed to the aluminum holder through the O-ring.
Then, 0.9 g of gas generating agent, identical with that used in
Example 1, was measured and then was packed in the first aluminum
cup. Then, the separator, in which the O-ring was fitted in the
groove circularly formed around the outside surface of the
generally cylinder aluminum body, was inserted in the first cup
packed with the gas generating agents, so as to contact with the
inside surface of the first cup. Then, the separator was set in
position by the protrusion formed around the inside surface of the
first cup. Finally, the holder in which the igniter was fixed was
inserted in the first cup and was fixed thereto by crimping.
Example 3
[0127] The gas generator as shown in FIG. 3 was produced. First,
0.9 g of gas generating agent, identical with that used in Example
1, was measured and then was packed in the first aluminum cup.
Then, the sheet packing was fitted to the aluminum holder and then
that holder was inserted in the cup packed with the gas generating
agents. Then, the igniter was inserted in the separator and the
O-ring was fitted to the separator. Finally, the aluminum holder
was inserted in the separator and was fixed thereto by crimping. At
this tine, the separator was set in position by the crimping
portions of the first cup and holder.
Example 4
[0128] The gas generator as shown in FIG. 4 was produced. First,
the igniter was inserted in the separator, Then, after the sealant
was applied to the crimping portions of the separator and holder,
the separator and holder were crimped, together with the igniter,
so that the separator and the igniter are fixed to the holder.
Then, 0.9 g of gas generating agent, identical with that used in
Example 1, was measured and then was packed in the first aluminum
cup. Finally, the aluminum holder was inserted in the first cup
packed with the gas generating agents, with the O-ring interposed
therebetween, and was fixed to the first cup by crimping.
Comparative Example 1
[0129] The gas generator as shown in FIG. 9 was produced. First,
the igniter was fixed to the aluminum holder, with the O-ring
interposed therebetween. Then, 0.9 g of gas generating agent,
identical with that used in Example 1, was measured and then was
packed in the first aluminum cup. Finally, after the holder to
which the igniter was fixed was inserted in the first cup and the
sealant was applied to the crimping portions of the first cup and
holder, the first cup was fixed to the holder by crimping.
[0130] The results of the moisture-absorption test and measurement
of the ignition time delay of Examples 1 to 4 and Comparative
Example 1 mentioned above are shown in Table 1 in FIG. 10.
[0131] Moisture absorption quantity of gas generating agent was
calculated according to the equation given below.
Moisture absorption quantity of gas generating agent=(mass of gas
generating agent after moisture absorption test-mass of gas
generating agent before moisture absorption test).div.mass of gas
generating agent before moisture absorption test.times.100
[0132] It is seen from Table 1 that in Examples 1 to 4, the
moisture absorption quantity of gas generating agent after moisture
absorption test is reduced to 0.3 percent by mass or less and no
performance decrement of the gas generator of Examples is caused.
In contrast, in Comparative Example 1, 1.5 mass percent of moisture
absorption quantity is found and the burning velocity of the gas
generating agent is reduced so that the gas generator cannot
exhibit its full performance.
[0133] Also, in Examples 1 to 4, the ignition time delay as short
as less than 2 ms is achieved. In contrast, in Comparative Example
1, the ignition time delay is as long as 2.2 ms so that the gas
generator delays in actuation and the gas generator cannot exhibit
its fill performance.
CAPABILITY OF EXPLOITATION IN INDUSTRY
[0134] The gas generator of the present invention is optimum for
the gas generator that is less subject to atmospheric moisture,
operates without time delay, and exhibits its full performance for
a seatbelt pretensioner and the like system.
* * * * *