U.S. patent application number 13/978483 was filed with the patent office on 2013-10-24 for gas generator.
This patent application is currently assigned to ADVANCED TECHNOLOGY & SOLUTION CO., LTD.. The applicant listed for this patent is Jin Han Kim, Hirotaka Mukunoki, Satoshi Ohsugi, Yusuke Tanaka. Invention is credited to Jin Han Kim, Hirotaka Mukunoki, Satoshi Ohsugi, Yusuke Tanaka.
Application Number | 20130276664 13/978483 |
Document ID | / |
Family ID | 46457570 |
Filed Date | 2013-10-24 |
United States Patent
Application |
20130276664 |
Kind Code |
A1 |
Ohsugi; Satoshi ; et
al. |
October 24, 2013 |
GAS GENERATOR
Abstract
A gas generator includes a lower shell, an upper shell, a
holding portion, an igniter, and a filter. The lower shell is made
of a press-formed product formed by press-working one plate-shaped
member made of metal, and includes a protruding cylindrical portion
and an opening provided in the protruding cylindrical portion. The
holding portion is formed from a resin-molded portion formed by
attaching an insulating fluid resin material to a bottom plate
portion so as to reach a part of an outer surface from a part of an
inner surface of the bottom plate portion of the lower shell
through the opening and solidifying the same, and includes an
accommodation recess portion in a portion opposed to a top plate
portion. The igniter is held by the holding portion while it is
inserted in the accommodation recess portion from a side of the top
plate portion and fitted therein.
Inventors: |
Ohsugi; Satoshi;
(Himeji-shi, JP) ; Tanaka; Yusuke; (Himeji-shi,
JP) ; Mukunoki; Hirotaka; (Himeji-shi, JP) ;
Kim; Jin Han; (GimHae-Si, KR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Ohsugi; Satoshi
Tanaka; Yusuke
Mukunoki; Hirotaka
Kim; Jin Han |
Himeji-shi
Himeji-shi
Himeji-shi
GimHae-Si |
|
JP
JP
JP
KR |
|
|
Assignee: |
ADVANCED TECHNOLOGY & SOLUTION
CO., LTD.
GimHae-Si, GyeongSangNam-Do
KR
NIPPON KAYAKU KABUSHIKI KAISHA
Chiyoda-ku, Tokyo
JP
|
Family ID: |
46457570 |
Appl. No.: |
13/978483 |
Filed: |
January 6, 2012 |
PCT Filed: |
January 6, 2012 |
PCT NO: |
PCT/JP2012/050176 |
371 Date: |
July 5, 2013 |
Current U.S.
Class: |
102/530 |
Current CPC
Class: |
C06D 5/00 20130101; B60R
21/2644 20130101; B60R 2021/26076 20130101; B60R 2021/26029
20130101 |
Class at
Publication: |
102/530 |
International
Class: |
C06D 5/00 20060101
C06D005/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 7, 2011 |
JP |
2011-001939 |
Claims
1. A gas generator, comprising: a short cylindrical housing which
is constituted of a top plate portion and a bottom plate portion
closing axial end portions and a circumferential wall portion
provided with a gas discharge opening and includes therein a
combustion chamber accommodating a gas generating agent; an igniter
for burning said gas generating agent; and a holding portion
provided on said bottom plate portion, for holding said igniter,
said housing at least having a lower shell including said bottom
plate portion and an upper shell including said top plate portion,
said lower shell including a protruding cylindrical portion
provided to protrude toward said top plate portion and an opening
provided at an axial end portion of said protruding cylindrical
portion, which is located on a side of said top plate portion, said
holding portion being formed from a resin-molded portion which is
formed by attaching a fluid resin material to said bottom plate
portion so as to reach a part of an outer surface of said bottom
plate portion from a part of an inner surface of said bottom plate
portion through said opening and solidifying the fluid resin
material so that at least a part of the resin-molded portion is
secured to said bottom plate portion and including an accommodation
recess portion for accommodating said igniter in a portion opposed
to said top plate portion, and said igniter being held by said
holding portion while it is inserted in said accommodation recess
portion from a side of said top plate portion and fitted in said
accommodation recess portion.
2. The gas generator according to claim 1, wherein one of said
igniter and said holding portion is provided with a locking
portion, the other of said igniter and said holding portion is
provided with a locked portion, and said igniter is held by said
holding portion as said locking portion is locked to said locked
portion.
3. The gas generator according to claim 2, wherein said locking
portion has a groove portion extending along a circumferential
direction, in a portion on a main surface on a side locked to said
locked portion, which corresponds to a root of said locking
portion.
4. The gas generator according to claim 1, wherein said igniter is
held by said holding portion by being fixed to said holding portion
with an adhesive.
5. The gas generator according to claim 1, further comprising a
first rotation prevention mechanism for preventing said igniter
from rotating relative to said holding portion.
6. The gas generator according to claim 1, further comprising a
second rotation prevention mechanism for preventing said holding
portion from rotating relative to said lower shell.
7. The gas generator according to claim 1, wherein said lower shell
is made of a press-formed product formed by press-working one
plate-shaped member made of metal.
8. The gas generator according to claim 1, wherein said igniter
includes an agent loaded portion accommodating an agent for burning
said gas generating agent and a terminal pin connected to said
agent loaded portion for igniting said agent, and said terminal pin
is arranged to pass through said opening in said lower shell.
9. The gas generator according to claim 8, wherein said holding
portion includes an insertion hole through which said terminal pin
is inserted, said terminal pin has, in a root portion, a flexion
portion which is formed such that a part thereof juts out, said
insertion hole has a site allowing reception of said flexion
portion of said terminal pin, in a portion facing said
accommodation recess portion, and the site allowing reception of
said flexion portion is provided only at a prescribed position in a
circumferential direction around a central axis of said insertion
hole.
Description
TECHNICAL FIELD
[0001] The present invention relates to a gas generator
incorporated in a passenger protection apparatus, and more
particularly to what is called a disc type gas generator
incorporated in an air bag apparatus equipped in a steering wheel
or the like of a car.
BACKGROUND ART
[0002] From a point of view of protection of a driver and/or a
passenger in a car or the like, an air bag apparatus which is a
passenger protection apparatus has conventionally widely been used.
The air bag apparatus is equipped for the purpose of protecting a
driver and/or a passenger against shock caused at the time of
collision of a vehicle or the like, and it receives a body of a
driver or a passenger with an air bag serving as a cushion, as the
air bag is expanded and developed instantaneously at the time of
collision of the vehicle or the like. The gas generator is
equipment which is incorporated in this air bag apparatus, an
igniter therein being ignited in response to power feed through a
control unit at the time of collision of a vehicle or the like to
thereby burn a gas generating agent with flame caused by the
igniter and instantaneously generate a large amount of gas, and
thus expands and develops an air bag. It is noted that the air bag
apparatus is equipped, for example, in a steering wheel, an
instrument panel, or the like of a car.
[0003] Gas generators of various structures are available, and in
particular, what is called a disc type gas generator is available
as a gas generator suitably made use of for a driver-seat-side air
bag apparatus equipped in a steering wheel or the like. In general,
the disc type gas generator has a short cylindrical housing of
which axial end portions are closed, a gas discharge opening being
provided in a circumferential wall of the housing, and the housing
accommodating a gas generating agent, an igniter, a filter, and the
like.
[0004] The housing of the disc type gas generator is generally
constituted of combination of a cylindrical metal member with
bottom called a lower shell and a cylindrical metal member with
bottom called an upper shell. Of these shells, the lower shell
forms at least a bottom plate portion of the housing, to which the
igniter is assembled and fixed.
[0005] A shape of the upper shell has conventionally relatively
been simple, and hence it has generally been fabricated by
press-working one plate-shaped member made of metal. In contrast,
since a shape of a portion of the lower shell to which the igniter
is to be assembled has been complicated, the lower shell has
generally been fabricated by cutting that portion (a portion of the
lower shell to serve as an igniter fixation portion). Fabrication
of the lower shell through such cutting, however, has put
significant pressure on manufacturing cost, and hence improvement
thereof has been demanded.
[0006] Then, an attempt to simplify a construction of the lower
shell, fabricate the lower shell by press-working one plate-shaped
member made of metal, and fix an igniter to the lower shell
fabricated by press-working by means of a resin-molded portion
through insert molding has been made. For example, Japanese Patent
Laying-Open No. 4-266548 (PTD 1), Japanese National Patent
Publication No. 2005-528276 (PTD 2), Japanese National Patent
Publication No. 2007-521181 (PTD 3), Japanese Patent Laying-Open
No. 2010-173558 (PTD 4), Japanese Patent Laying-Open No.
2010-173559 (PTD 5), Japanese Patent Laying-Open No. 2010-173560
(PTD 6), and the like are exemplified as documents disclosing such
a construction.
[0007] In the gas generator disclosed in any of the documents
above, such a construction that an igniter is assembled to a lower
shell formed by press-working one plate-shaped member made of metal
through insert molding with a resin material serving as a source
material has been adopted. More specifically, an insulating fluid
resin material is poured into a space between the lower shell and
the igniter arranged in an opening provided in the lower shell and
then solidified, to thereby form a resin-molded portion, and the
resin molded portion is secured to a surface of the igniter and a
surface of the lower shell, so that the igniter is fixed to the
lower shell.
CITATION LIST
Patent Document
[0008] PTD 1: Japanese Patent Laying-Open No. 4-266548 [0009] PTD
2: Japanese National Patent Publication No. 2005-528276 [0010] PTD
3: Japanese National Patent Publication No. 2007-521181 [0011] PTD
4: Japanese Patent Laying-Open No. 2010-173558 [0012] PTD 5:
Japanese Patent Laying-Open No. 2010-173559 [0013] PTD 6: Japanese
Patent Laying-Open No. 2010-173560
SUMMARY OF INVENTION
Technical Problem
[0014] In a case where the construction as disclosed in any of the
documents above is adopted, however, exposure of the igniter to a
high-temperature and high-pressure environment during insert
molding gives rise to a problem. Namely, since the igniter is a
part in which an ignition agent or the like sensitively reactive to
static electricity, flame, or the like is loaded, handling thereof
requires great care. Exposure of the igniter to the
high-temperature and high-pressure environment as above, however,
involves considerable difficulty in ensuring safety in assembly
operations. Then, the assembly operations are significantly
restricted, which has resulted in impediment to easy manufacturing
of a gas generator.
[0015] Therefore, the present invention was made to solve the
problems described above, and an object thereof is to provide a gas
generator which can achieve reduced cost, have less restriction in
assembly operations, and can safely and readily be
manufactured.
Solution to Problem
[0016] A gas generator based on the present invention includes a
housing, an igniter, and a holding portion. The housing is made of
a short cylindrical member which is constituted of a top plate
portion and a bottom plate portion closing axial end portions and a
circumferential wall portion provided with a gas discharge opening
and includes therein a combustion chamber accommodating a gas
generating agent. The igniter serves for burning the gas generating
agent. The holding portion is provided on the bottom plate portion
and holds the igniter. The housing at least has a lower shell
including the bottom plate portion and an upper shell including the
top plate portion, and the lower shell includes a protruding
cylindrical portion provided to protrude toward the top plate
portion and an opening provided at an axial end portion of the
protruding cylindrical portion, which is located on a side of the
top plate portion. The holding portion is formed from a
resin-molded portion which is formed by attaching a fluid resin
material to the bottom plate portion so as to reach a part of an
outer surface of the bottom plate portion from a part of an inner
surface of the bottom plate portion through the opening and
solidifying the fluid resin material so that at least a part of the
resin-molded portion is secured to the bottom plate portion, and
includes an accommodation recess portion for accommodating the
igniter in a portion opposed to the top plate portion. The igniter
is held by the holding portion while it is inserted in the
accommodation recess portion from a side of the top plate portion
and fitted in the accommodation recess portion.
[0017] In the gas generator based on the present invention above,
preferably, one of the igniter and the holding portion is provided
with a locking portion and the other of the igniter and the holding
portion is provided with a locked portion, and in that case,
preferably, the igniter is held by the holding portion as the
locking portion is locked to the locked portion.
[0018] In the gas generator based on the present invention above,
preferably, the locking portion has a groove portion extending
along a circumferential direction, in a portion on a main surface
on a side locked to the locked portion, which corresponds to a root
of the locking portion.
[0019] In the gas generator based on the present invention above,
preferably, the igniter may be held by the holding portion by being
fixed to the holding portion with an adhesive.
[0020] The gas generator based on the present invention above may
further include a first rotation prevention mechanism for
preventing the igniter from rotating relative to the holding
portion.
[0021] The gas generator based on the present invention above may
further include a second rotation prevention mechanism for
preventing the holding portion from rotating relative to the lower
shell.
[0022] In the gas generator based on the present invention above,
preferably, the lower shell is made of a press-formed product
formed by press-working one plate-shaped member made of metal.
[0023] In the gas generator based on the present invention above,
preferably, the igniter includes an agent loaded portion
accommodating an agent for burning the gas generating agent and a
terminal pin connected to the agent loaded portion for igniting the
agent, and in that case, preferably, the terminal pin is arranged
to pass through the opening in the lower shell. Moreover, in that
case, a size of the opening is preferably smaller than a size of
the igniter at a portion of the agent loaded portion largest in
outer shape.
[0024] In the gas generator based on the present invention above,
preferably, the holding portion includes an insertion hole through
which the terminal pin is inserted, and preferably, the terminal
pin has, in a root portion, a flexion portion formed such that a
part thereof juts out. In that case, the insertion hole preferably
has a site allowing reception of the flexion portion of the
terminal pin in a portion facing the accommodation recess portion,
and in addition in that case, the site allowing reception of the
flexion portion is preferably provided only at a prescribed
position in a circumferential direction around a central axis of
the insertion hole.
[0025] In the gas generator based on the present invention above,
preferably, the holding portion includes a female connector portion
capable of receiving a male connector in a portion facing outside,
and in that case, the female connector portion is preferably
located within the protruding cylindrical portion.
Advantageous Effects of Invention
[0026] According to the present invention, a gas generator which
can achieve reduced cost, have less restriction in assembly
operations, and can safely and readily be manufactured can be
obtained.
BRIEF DESCRIPTION OF DRAWINGS
[0027] FIG. 1 is a schematic diagram of a gas generator in
Embodiment 1 of the present invention.
[0028] FIG. 2 is a schematic diagram of an area in the vicinity of
an igniter of the gas generator in Embodiment 1 of the present
invention.
[0029] FIG. 3 is a schematic diagram for illustrating a structure
for assembly and a procedure for assembly of the igniter of the gas
generator in Embodiment 1 of the present invention.
[0030] FIG. 4A is a plan view of a holding portion of the gas
generator in Embodiment 1 of the present invention.
[0031] FIG. 4B is a bottom view of the igniter of the gas generator
in Embodiment 1 of the present invention.
[0032] FIG. 5 is a schematic diagram of an area in the vicinity of
the igniter of the gas generator according to a first variation
based on Embodiment 1 of the present invention.
[0033] FIG. 6A is a plan view of the holding portion of the gas
generator according to a second variation based on Embodiment 1 of
the present invention.
[0034] FIG. 6B is a bottom view of the igniter of the gas generator
according to the second variation based on Embodiment 1 of the
present invention.
[0035] FIG. 7 is a schematic diagram of a gas generator in
Embodiment 2 of the present invention.
[0036] FIG. 8A is a plan view of the holding portion of the gas
generator in Embodiment 2 of the present invention.
[0037] FIG. 8B is a bottom view of the igniter of the gas generator
in Embodiment 2 of the present invention.
[0038] FIG. 9A is a plan view of the holding portion of a gas
generator according to a variation based on Embodiment 2 of the
present invention.
[0039] FIG. 9B is a bottom view of the igniter of the gas generator
according to the variation based on Embodiment 2 of the present
invention.
[0040] FIG. 10 is a schematic diagram of a gas generator in
Embodiment 3 of the present invention.
[0041] FIG. 11 is a schematic diagram of a gas generator in
Embodiment 4 of the present invention.
[0042] FIG. 12 is a schematic diagram of an area in the vicinity of
the igniter of the gas generator in Embodiment 4 of the present
invention.
[0043] FIG. 13 is a schematic diagram for illustrating a structure
for assembly and a procedure for assembly of the igniter of the gas
generator in Embodiment 4 of the present invention.
[0044] FIG. 14 is a schematic diagram for illustrating a structure
for assembly and a procedure for assembly of the igniter of the gas
generator according to a variation based on Embodiment 4 of the
present invention.
[0045] FIG. 15 is a schematic diagram of a gas generator in
Embodiment 5 of the present invention.
[0046] FIG. 16 is a schematic diagram of an area in the vicinity of
the igniter of the gas generator in Embodiment 5 of the present
invention.
[0047] FIG. 17 is a schematic diagram for illustrating a structure
for assembly and a procedure for assembly of the igniter of the gas
generator in Embodiment 5 of the present invention.
[0048] FIG. 18A is a plan view of the holding portion of the gas
generator in Embodiment 5 of the present invention.
[0049] FIG. 18B is a bottom view of the igniter of the gas
generator in Embodiment 5 of the present invention.
[0050] FIG. 19 is a diagram showing a state in a case where the
igniter has been inserted in an incorrect orientation in the gas
generator in Embodiment 5 of the present invention.
[0051] FIG. 20 is a schematic diagram of a gas generator according
to a first variation based on Embodiment 5 of the present
invention.
[0052] FIG. 21 is a schematic diagram for illustrating a structure
for assembly and a procedure for assembly of the igniter of the gas
generator according to the first variation based on Embodiment 5 of
the present invention.
[0053] FIG. 22 is a diagram showing a state in a case where the
igniter has been inserted in an incorrect orientation in the gas
generator according to the first variation based on. Embodiment 5
of the present invention.
[0054] FIG. 23 is a schematic diagram for illustrating a structure
for assembly and a procedure for assembly of the igniter of a gas
generator according to a second variation based on Embodiment 5 of
the present invention.
[0055] FIG. 24 is a schematic diagram of a gas generator in
Embodiment 6 of the present invention.
[0056] FIG. 25 is a schematic diagram of a gas generator in
Embodiment 7 of the present invention.
[0057] FIG. 26 is an enlarged view of a main portion of a gas
generator in Embodiment 8 of the present invention.
DESCRIPTION OF EMBODIMENTS
[0058] An embodiment of the present invention will be described
hereinafter in detail with reference to the drawings. An embodiment
and a variation thereof shown below represent application of the
present invention to a disc type gas generator incorporated in an
air bag apparatus equipped in a steering wheel or the like of a
car. It is noted that the same or common elements in the embodiment
and the variation thereof shown below have the same reference
characters allotted in the drawings and description thereof will
not be repeated.
Embodiment 1
[0059] FIG. 1 is a schematic diagram of a gas generator in
Embodiment 1 of the present invention. An overall structure of a
gas generator 1A in the present embodiment will initially be
described with reference to this FIG. 1.
[0060] As shown in FIG. 1, gas generator 1A in the present
embodiment has a short cylindrical housing having opposing axial
ends closed, and is constructed to accommodate as components in
this housing, a holding portion 30, an igniter 40, a gas generating
agent 61, a filter 70, and the like. The short cylindrical housing
includes a lower shell 10 and an upper shell 20. Each of lower
shell 10 and upper shell 20 is made of a press-formed product
formed by press-working one plate-shaped member made of metal.
[0061] Lower shell 10 and upper shell 20 are each formed in a
cylindrical shape with bottom, and an outer shell portion of the
housing is formed by combining and joining the shells such that
open surfaces thereof face each other. Lower shell 10 has a bottom
plate portion 11 and a circumferential wall portion 12 and upper
shell 20 has a top plate portion 21 and a circumferential wall
portion 22. It is noted that electron-beam welding, laser welding,
friction welding, or the like is suitably made use of for joining
lower shell 10 and upper shell 20 to each other.
[0062] A protruding cylindrical portion 13 protruding toward top
plate portion 21 is provided in a substantially central portion of
bottom plate portion 11 of lower shell 10, so that a depression
portion 14 is formed in the substantially central portion of bottom
plate portion 11 of lower shell 10. Protruding cylindrical portion
13 is a site to which igniter 40 is fixed with holding portion 30
being interposed, and depression portion 14 is a site serving as a
space for providing a female connector portion 36 in holding
portion 30. Here, protruding cylindrical portion 13 is formed to be
in a cylindrical shape with bottom, and tapered such that an outer
diameter thereof decreases toward top plate portion 21, In
addition, an opening 15 in a circular shape when viewed
two-dimensionally is provided at an axial end portion of protruding
cylindrical portion 13, which is located on a side of top plate
portion 21. Opening 15 is a site through which a pair of terminal
pins 42 of igniter 40 is inserted.
[0063] As described above, lower shell 10 is fabricated by
press-working one plate-shaped member made of metal. Specifically,
lower shell 10 is fabricated by using a pair of molds consisting of
an upper mold and a lower mold to press one plate-shaped member
made of metal in a vertical direction to thereby form the
plate-shaped member in a shape as illustrated.
[0064] Here, for example, a metal plate composed of stainless
steel, iron steel, an aluminum alloy, a stainless alloy, or the
like and having a thickness before pressing approximately not
smaller than 1.5 mm and not greater than 3.0 mm is made use of as
the plate-shaped member made of metal, and suitably, what is called
a high tensile steel plate which is free from such breakage as
fracture even at the time of application of tensile stress not
lower than 440 MPa and not higher than 780 MPa is suitably made use
of It is noted that, regarding a thickness after pressing, a
thickness of a smallest thickness portion is preferably not smaller
than approximately 1.0 mm. In addition, press-working may be
carried out through hot forging or cold forging, and from a point
of view of improvement in dimension accuracy, it is more suitably
carried out through cold forging.
[0065] As described above, upper shell 20 is fabricated by
press-working one plate-shaped member made of metal. Specifically,
upper shell 20 is fabricated by using a pair of molds consisting of
an upper mold and a lower mold to press one plate-shaped member
made of metal in a vertical direction to thereby form the
plate-shaped member in a shape as illustrated. Here, a metal plate
composed of stainless steel, iron steel, an aluminum alloy, a
stainless alloy, or the like can be made use of as the plate-shaped
member made of metal.
[0066] Holding portion 30 is provided around protruding cylindrical
portion 13 provided in the substantially central portion of bottom
plate portion 11 of lower shell 10. Holding portion 30 has an inner
coating portion 31 covering a part of an inner surface of bottom
plate portion 11 of lower shell 10, an outer coating portion 32
covering a part of an outer surface of bottom plate portion 11 of
lower shell 10, and a coupling portion 33 located within opening 15
provided in bottom plate portion 11 of lower shell 10 and
continuing to each of inner coating portion 31 and outer coating
portion 32.
[0067] This holding portion 30 is formed from a resin-molded
portion formed by attaching an insulating fluid resin material to
bottom plate portion 11 so as to reach a part of the outer surface
of bottom plate portion 11 from a part of the inner surface thereof
through opening 15 provided in bottom plate portion 11 of lower
shell 10 and solidifying the fluid resin material. Namely, holding
portion 30 is formed by injection molding with the use of a mold
(more particularly, outsert molding).
[0068] For a source material for holding portion 30 formed by
injection molding, a resin material excellent in heat resistance,
durability, corrosion resistance, and the like after curing is
suitably selected and made use of. In that case, without being
limited to a thermosetting resin represented by an epoxy resin and
the like, a thermoplastic resin represented by a polybutylene
terephthalate resin, a polyethylene terephthalate resin, a
polyamide resin (such as nylon 6 or nylon 66), a polypropylene
sulfide resin, a polypropylene oxide resin, and the like can also
be made use of. In a case where these thermoplastic resins are
selected as a source material, in order to ensure mechanical
strength of holding portion 30 after molding, glass fibers or the
like are preferably contained as fillers in these resin materials.
In a case where sufficient mechanical strength can be ensured only
by a thermoplastic resin, however, a filler as described above does
not have to be added.
[0069] Holding portion 30 is secured to bottom plate portion 11 at
a surface on a side of bottom plate portion 11, of each of inner
coating portion 31, outer coating portion 32, and coupling portion
33 described above. Here, holding portion 30 is provided to
entirely cover protruding cylindrical portion 13 provided in bottom
plate portion 11 of lower shell 10, so that protruding cylindrical
portion 13 is completely buried in holding portion 30.
[0070] In a portion of inner coating portion 31 of holding portion
30, which is opposed to top plate portion 21, a holding wall
portion 34 having an annular shape is erected toward top plate
portion 21, so that an accommodation recess portion 35 is provided
in holding portion 30. Accommodation recess portion 35 is a site
for receiving and accommodating a part of igniter 40.
[0071] In a portion of outer coating portion 32 of holding portion
30, which faces the outside, female connector portion 36 is formed.
This female connector portion 36 is a site for receiving a male
connector (not shown) of a harness for connecting igniter 40 and a
control unit (not shown) to each other, and it is located in
depression portion 14 provided in bottom plate portion 11 of lower
shell 10. In this female connector portion 36, a portion of
terminal pin 42 of igniter 40 closer to a lower end is arranged as
being exposed. The male connector is inserted in female connector
portion 36, so that electrical conduction between a core wire of
the harness and terminal pin 42 is established.
[0072] A pair of insertion holes 37a in a perfect circle shape when
viewed two-dimensionally is provided in coupling portion 33 of
holding portion 30. This pair of insertion holes 37a is a site
through which a pair of terminal pins 42 of igniter 40 is inserted,
and opposing ends thereof reach accommodation recess portion 35 and
female connector portion 36 described above, respectively.
[0073] Igniter 40 is an ignition device producing flame and thermal
particles for burning gas generating agent 61 and assembled to
holding portion 30 as a part thereof is accommodated in
accommodation recess portion 35 described above. Igniter 40
includes an agent loaded portion 41 in which an agent generating
flame and thermal particles as it burns is loaded and a pair of
terminal pins 42 connected to agent loaded portion 41 igniters
having various constructions can be made use of as igniter 40,
however, here, an igniter of a type in which an ignition agent and
an enhancer agent are loaded in agent loaded portion 41 is made use
of. It is noted that details of a structure for assembly of igniter
40 to holding portion 30 will be described later.
[0074] Agent loaded portion 41 contains an ignition agent
generating flame as it is ignited and burns at the time of
actuation, a resistor for igniting this ignition agent, and an
enhancer agent producing a large number of thermal particles as it
is ignited by the flame caused by burning of the ignition agent and
it burns. The pair of terminal pins 42 is connected to agent loaded
portion 41 for igniting the ignition agent.
[0075] More specifically, igniter 40 includes an igniter cup 41a
made of a cup-shaped member, a base portion 41b which closes an
opening end of igniter cup 41a and holds the pair of terminal pins
42 as the pins are inserted therethrough, and a lower cover 44
provided to cover a part of terminal pin 42 and base portion 41b,
and has such a construction that the resistor (bridge wire) is
attached to couple tip ends of the pair of terminal pins 42
inserted in igniter cup 41a to each other, the ignition agent is
loaded into igniter cup 41a so as to surround or be proximate to
this resistor, and the enhancer agent is loaded to be in contact
with the ignition agent.
[0076] Here, a Nichrome wire or the like is generally made use of
as a resistor, and ZPP (zirconium potassium perchlorate), ZWPP
(zirconium tungsten potassium perchlorate), lead tricinate, or the
like is generally made use of as the ignition agent. In addition,
the enhancer agent should be able to reliably start burning gas
generating agent 61 which will be described later, and generally, a
composition or the like composed of metal powders/oxidizing agent
represented by B/KNO.sub.3 or the like is employed. For the
enhancer agent, a powdery enhancer agent, an enhancer agent formed
in a prescribed shape by a binder, or the like is made use of. A
shape of the enhancer agent formed by a binder includes, for
example, various shapes such as a granule, a column, a sheet, a
sphere, a cylinder with a single hole, a cylinder with multiple
holes, a tablet, and the like. It is noted that igniter cup 41a and
base portion 41b are generally made of metal or plastic, and lower
cover 44 is generally made of plastic.
[0077] Upon sensing collision, a prescribed amount of current flows
in a resistor through terminal pin 42. As the prescribed amount of
current flows in the resistor, Joule heat is generated in the
resistor and the ignition agent starts burning. Flame at a high
temperature caused by burning burns the enhancer agent and produces
a large number of thermal particles. As the enhancer agent burns, a
pressure and a temperature within igniter cup 41a increase, igniter
cup 41a bursts or melts, and the thermal particles are released to
the outside of igniter 40.
[0078] A sealing member 50 is interposed between igniter 40 and
holding portion 30. More specifically, sealing member 50 is
arranged between a bottom surface and an inner circumferential
surface of accommodation recess portion 35 of holding portion 30
and an outer circumferential surface of lower cover 44 of igniter
40. Sealing member 50 serves to hermetically seal a combustion
chamber 60 which will be described later by air tightly sealing a
gap created between igniter 40 and holding portion 30, and it is
inserted in the gap during assembly of igniter 40 to holding
portion 30.
[0079] A sealing member made of a material having sufficient heat
resistance and durability is preferably made use of as sealing
member 50, and for example, an O ring or the like made of an EPDM
resin representing one type of ethylene propylene rubber is
suitably made use of it is noted that hermeticity of combustion
chamber 60 can further be enhanced by separately applying a liquid
sealing agent to a portion where sealing member 50 is to be
interposed. Here, a liquid sealing agent containing a resin
material excellent in heat resistance, durability, corrosion
resistance, and the like after curing is suitably selected and made
use of as the liquid sealing agent, and for example, a
cyanoacrylate-based resin or a silicone-based resin is particularly
suitably made use of as the resin material. In addition, for the
resin material, other than the resin materials described above, a
phenol-based resin, an epoxy-based resin, a melamine-based resin, a
urea-based resin, a polyester-based resin, an alkyd-based resin, a
polyurethane-based resin, a polyimide-based resin, a
polyethylene-based resin, a polypropylene-based resin, a polyvinyl
chloride-based resin, a polystyrene-based resin, a polyvinyl
acetate-based resin, a polytetrafluoroethylene-based resin, an
acrylonitrile butadiene styrene-based resin, an acrylonitrile
styrene-based resin, an acryl-based resin, a polyamide-based resin,
a polyacetal-based resin, a polycarbonate-based resin, a
polyphenylene ether-based resin, a polybutylene terephthalate-based
resin, a polyethylene terephthalate-based resin, a polyolefin-based
resin, a polyphenylene sulfide-based resin, a polysulfone-based
resin, a polyether sulfone-based resin, a polyarylate-based resin,
a polyether ether ketone-based resin, a polyamide imide-based
resin, a liquid crystal polymer, and the like can be made use
of.
[0080] Combustion chamber 60 accommodating gas generating agent 61
is located in a space surrounding a portion where holding portion
30 and igniter 40 described above are arranged, in the space inside
the housing constituted of lower shell 10 and upper shell 20. More
specifically, holding portion 30 and igniter 40 described above are
arranged to protrude from bottom plate portion 11 of lower shell 10
toward the inside of the housing, and a space provided in a portion
facing these holding portion 30 and igniter 40 is formed as
combustion chamber 60.
[0081] In addition, in a space surrounding combustion chamber 60 in
a radial direction of the housing, a filter 70 is arranged along an
inner circumference of the housing. Filter 70 has a hollow
cylindrical shape, and a central axis thereof is arranged to
substantially match with the axial direction of the housing.
[0082] Gas generating agent 61 is an agent which is ignited by
thermal particles generated as a result of actuation of igniter 40
and produces a gas as it burns. A non-azide-based gas generating
agent is preferably employed as gas generating agent 61, and gas
generating agent 61 is formed as a molding generally containing a
fuel, an oxidizing agent, and an additive. For the fuel, for
example, a triazole derivative, a tetrazole derivative, a guanidine
derivative, an azodicarbonamide derivative, a hydrazine derivative,
or the like, or combination thereof is made use of Specifically,
for example, nitroguanidine, guanidine nitrate, cyanoguanidine,
5-aminotetrazole, and the like are suitably made use of. In
addition, as the oxidizing agent, for example, basic nitrate such
as basic copper nitrate, perchlorate such as ammonium perchlorate
or potassium perchlorate, nitrate containing cations selected from
an alkali metal, an alkali earth metal, a transition metal, and
ammonia, or the like is made use of. As the nitrate, for example,
sodium nitrate, potassium nitrate, or the like is suitably made use
of. Moreover, as the additive, a binder, a slag formation agent, a
combustion modifier, or the like is exemplified. As the binder, for
example, metal salt of carboxymethyl cellulose, an organic binder
such as stearate, or an inorganic binder such as synthetic
hydrotalcite and Japanese acid clay can suitably be made use of. As
the slag formation agent, silicon nitride, silica, Japanese acid
clay, or the like can suitably be made use of. In addition, as the
combustion modifier, a metal oxide, ferrosilicon, activated carbon,
graphite, or the like can suitably be made use of.
[0083] A shape of a molding of gas generating agent 61 includes
various shapes such as a particulate shape including a granule, a
pellet, and a column, and a disc shape. In addition, among columnar
moldings, a molding with holes having holes in the molding (such as
a cylindrical shape with a single hole or a cylindrical shape with
multiple holes) is also made use of. These shapes are preferably
selected as appropriate depending on specifications of an air bag
apparatus in which gas generator 1A is incorporated, and for
example, a shape optimal for the specifications is preferably
selected by selecting a shape allowing change over time of a rate
of generation of a gas during burning of gas generating agent 61.
Furthermore, in addition to a shape of gas generating agent 61, a
size of a molding or an amount thereof for filling is preferably
selected as appropriate, in consideration of a linear burning
velocity, a pressure exponent, or the like of gas generating agent
61.
[0084] For example, a filter obtained by winding and sintering a
metal wire rod of stainless steel or iron steel, a filter formed by
press-working a mesh material into which metal wire rods are
knitted to thereby pack the same, a filter obtained by winding a
perforated metal plate, or the like is made use of as filter 70.
Here, as the mesh material, specifically, a wire gauze of stocking
stitch, a plain-woven wire gauze, an aggregate of crimped metal
wire rods, or the like is made use of. In addition, as the
perforated metal plate, for example, expanded metal obtained by
making staggered cuts in a metal plate and forming holes by
widening the cuts to thereby work the metal plate in a mesh, hook
metal obtained by perforating a metal plate and collapsing burrs
caused around a periphery of the hole for flattening, or the like
is made use of. In this case, a size or a shape of a hole to be
formed can be changed as appropriate as required, and holes
different in size or shape may be included in the same metal plate.
It is noted that, for example, a steel plate (mild steel) or a
stainless steel plate can suitably be made use of as a metal plate,
and a nonferrous metal plate of aluminum, copper, titanium, nickel,
or an alloy thereof, or the like can also be made use of.
[0085] Filter 70 functions as cooling means for cooling a gas by
depriving heat at a high temperature of the gas when the gas
produced in combustion chamber 60 passes through this filter 70 and
also functions as removal means for removing residues (slag) or the
like contained in the gas. Therefore, in order to sufficiently cool
the gas and to avoid emission of the residue to the outside, the
gas produced in combustion chamber 60 should be caused to reliably
pass through filter 70.
[0086] A plurality of gas discharge openings 23 are provided in
circumferential wall portion 22 of upper shell 20 in a portion
facing filter 70. This gas discharge opening 23 serves for guiding
a gas which has passed through filter 70 to the outside of the
housing. To a main surface of circumferential wall portion 22 of
upper shell 20, which is located on a side of filter 70, a sealing
member 24 is attached to close gas discharge opening 23. An
aluminum foil or the like having an adhesive member applied to its
one surface is made use of as this sealing member 24. Thus,
hermeticity of combustion chamber 60 is ensured.
[0087] In the space inside the housing, an upper-side supporting
member 62 for fixing an upper end of filter 70 to the housing is
arranged at an end portion of upper shell 20 on the side of top
plate portion 21. Upper-side supporting member 62 has a site
abutting to top plate portion 21 of upper shell 20 and a site
abutting to an inner circumferential surface of an upper end
portion of filter 70.
[0088] In this upper-side supporting member 62, a cushion material
64 is arranged to be in contact with gas generating agent 61
accommodated in combustion chamber 60. This cushion material 64 is
provided for the purpose of preventing gas generating agent 61 made
of a molding from being crushed by vibration or the like, and a
molding of ceramics fibers or a foamed resin (such as foamed
silicone) is suitably made use of.
[0089] On the other hand, at an end portion of lower shell 10 on
the side of bottom plate portion 11 in the space inside the
housing, a lower-side supporting member 63 for fixing a lower end
of filter 70 to the housing is arranged. Lower-side supporting
member 63 has a site abutting to an inner bottom surface of bottom
plate portion 11 of lower shell 10 and a site abutting to an inner
circumferential surface of a lower end portion of filter 70.
[0090] These upper-side supporting member 62 and lower-side
supporting member 63 are formed, for example, by press-working or
the like a plate-shaped member made of metal, and a steel plate of
common steel, special steel, or the like (such as a cold rolled
steel plate or a stainless steel plate) is suitably employed. Since
upper-side supporting member 62 and lower-side supporting member 63
are formed by folding a part of the plate-shaped member made of
metal as described above, upper-side supporting member 62 and
lower-side supporting member 63 each have moderate elasticity.
Therefore, upper-side supporting member 62 and lower-side
supporting member 63 are in contact with the inner circumferential
surface of filter 70, so that filter 70 is held and fixed to the
housing. In addition, each of upper-side supporting member 62 and
lower-side supporting member 63 also has a function to prevent a
gas from flowing out through a gap between the upper end of filter
70 and top plate portion 21 of upper shell 20 and a gap between the
lower end of filter 70 and bottom plate portion 11 of lower shell
10.
[0091] An operation of gas generator 1A in the present embodiment
will now be described with reference to FIG. 1.
[0092] When a vehicle on which gas generator 1A in the present
embodiment is mounted collides, collision sensing means separately
provided in the vehicle senses collision, and based thereon,
igniter 40 is actuated in response to power feed through a control
unit separately provided in the vehicle. As igniter 40 is actuated,
the ignition agent and the enhancer agent loaded in agent loaded
portion 41 of igniter 40 burn and igniter cup 41a bursts or melts,
so that a large number of thermal particles flow into combustion
chamber 60.
[0093] The thermal particles which have flowed in ignite and burn
gas generating agent 61 accommodated in combustion chamber 60 and a
large amount of gas is produced. The gas produced in combustion
chamber 60 passes through filter 70. At that time, heat is deprived
of the gas through filter 70 and the gas is cooled, slag contained
in the gas is removed by filter 70, and the gas flows into an outer
peripheral portion of the housing.
[0094] As an internal pressure in the housing increases, sealing by
sealing member 24 which has closed gas discharge opening 23 of
upper shell 20 is broken, and the gas is discharged to the outside
of the housing through gas discharge opening 23. The discharged gas
is introduced in the air bag provided adjacent to gas generator 1A
and it expands and develops the air bag.
[0095] FIG. 2 is a schematic diagram of an area in the vicinity of
the igniter of the gas generator in the present embodiment. FIG. 3
is a schematic diagram for illustrating a structure for assembly
and a procedure for assembly of the igniter of the gas generator in
the present embodiment. In addition, FIG. 4A is a plan view of the
holding portion of the gas generator in the present embodiment, and
FIG. 4B is a bottom view of the igniter. A structure for assembly,
a procedure for assembly, and the like of igniter 40 of gas
generator 1A in the present embodiment will be described in detail
with reference to these FIGS. 2, 3, 4A, and 4B, in addition to FIG.
1 described above.
[0096] As shown in FIGS. 1 and 2, in gas generator 1A in the
present embodiment, lower cover 44 which is a part of igniter 40 is
held by holding portion 30 while it is fitted in accommodation
recess portion 35 provided in holding portion 30.
[0097] Specifically, as shown in FIGS. 2 and 3, holding wall
portion 34 having an annular shape defining accommodation recess
portion 35 of holding portion 30 has a plurality of locking pawl
portions 34a provided to align along a circumferential direction at
an end portion thereof on the side of top plate portion 21, and
locking pawl portions 34a are all formed such that their tip ends
face inward. The plurality of locking pawl portions 34a are sites
corresponding to a locking portion for fixing igniter 40 to holding
portion 30, which are integrally provided simultaneously with other
sites of holding portion 30 at the time of injection molding of
holding portion 30. Therefore, the plurality of locking pawl
portions 34a are all elastically deformable, and holding wall
portion 34 itself is elastically deformable.
[0098] On the other hand, as shown in FIGS. 1 to 3, lower cover 44
of igniter 40 has a site of which outer shape is formed to be
greater than agent loaded portion 41 (that is, a site extending
radially outward), and the site corresponds to the locked portion
for fixing igniter 40 to holding portion 30. The site extends
annularly along a circumferential direction, and includes inclined
upper surface and lower surface and a circumferential surface
continuing to these upper surface and lower surface.
[0099] In assembly, as shown in FIG. 3, while holding portion 30
formed from the resin-molded portion is formed in advance through
injection molding in bottom plate portion 11 of lower shell 10 and
sealing member 50 is accommodated within accommodation recess
portion 35 of holding portion 30, igniter 40 is inserted into
accommodation recess portion 35 from above (that is, the side of
top plate portion 21 after assembly). Here, a pair of terminal pins
42 of igniter 40 is inserted in a pair of insertion holes 37a
provided in coupling portion 33 of holding portion 30.
[0100] Here, locking pawl portions 34a of holding portion 30 come
in contact with the inclined lower surface of lower cover 44 of
igniter 40. As described above, however, since locking pawl
portions 34a and holding wall portion 34 are elastically
deformable, locking pawl portions 34a and holding wall portion 34
retract radially outward, so that lower cover 44 of igniter 40 can
be inserted in accommodation recess portion 35.
[0101] Then, after igniter 40 is inserted in holding portion 30,
locking pawl portions 34a go beyond a side portion of lower cover
44 so that locking pawl portions 34a and holding wall portion 34
return to their original shapes and locking pawl portions 34a are
locked to the inclined upper surface of lower cover 44 described
above. Thus, igniter 40 is fitted in accommodation recess portion
35 while lower cover 44 thereof is accommodated in accommodation
recess portion 35 of holding portion 30, and thus igniter 40 is
held by holding portion 30.
[0102] It is noted that, as shown in FIGS. 4A and 4B, since
coupling portion 33 of holding portion 30 is provided with a pair
of insertion holes 37a in a shape corresponding to a pair of
terminal pins 42 of igniter 40, positioning of igniter 40 with
respect to holding portion 30 can readily be achieved by inserting
the pair of terminal pins 42 in the pair of insertion holes 37a
during assembly of igniter 40 to holding portion 30 described above
and igniter 40 can be prevented from rotating relative to holding
portion 30 after assembly. Therefore, the pair of insertion holes
37a themselves provided in coupling portion 33 corresponds to the
first rotation prevention mechanism.
[0103] As described above, since gas generator 1A in the present
embodiment is constructed such that igniter 40 is assembled,
separately by fitting, to holding portion 30 which is the
resin-molded portion formed in advance through injection molding,
igniter 40 is not insert-molded at the time of injection molding of
holding portion 30. Therefore, igniter 40 which is a part in which
an ignition agent or the like sensitively reactive to static
electricity, flame, or the like is loaded is not exposed to a
high-temperature and high-pressure environment during assembly and
safety during the assembly operations can be ensured. Therefore,
restrictions imposed during the assembly operations are
significantly lessened; for example, a place where an operation for
injection molding is to be performed is not restricted.
[0104] On the other hand, since assembly of igniter 40 to holding
portion 30 can be realized through an operation only for inserting
igniter 40 in holding portion 30, assembly can very readily be
achieved. In addition, since holding portion 30 holding igniter 40
is formed through injection molding, a specific shape thereof can
variously be changed by changing a shape of a mold and a structure
of a locking portion for locking igniter 40 can readily be changed
to a structure suited to a shape of igniter 40. Therefore,
depending on a shape of igniter 40 to be used, any shape of holding
portion 30 allowing easier assembly can be selected and thus a
degree of freedom in design can highly be ensured.
[0105] In addition, since holding portion 30 for fixing igniter 40
to lower shell 10 is formed by injection molding, holding portion
30 is in a state secured to lower shell 10 and sealability at that
portion can sufficiently be ensured. Namely, as described above, as
inner coating portion 31, outer coating portion 32, and coupling
portion 33 constitute holding portion 30, a moderately long margin
for securing between lower shell 10 and holding portion 30 can be
ensured. Therefore, occurrence of peel-off at an interface portion
between lower shell 10 and holding portion 30 can be prevented and
sealability can reliably be maintained for a long period of
time.
[0106] Furthermore, since holding portion 30 for fixing igniter 40
to lower shell 10 is formed by injection molding, an effect of
lighter weight of the holding portion, an effect of being free from
burr caused in the case of cutting, ensured reproducibility of a
shape of the holding portion, and less likeliness of variation in
performance, as well as an effect of ability to prevent dielectric
breakdown due to occurrence of burr can also be obtained, as
compared with a case where the holding portion is formed by cutting
lower shell 10.
[0107] It is noted that gas generator 1A in the present embodiment
described above is constructed such that a size of opening 15
provided in protruding cylindrical portion 13 of lower shell 10 is
made smaller than a size of base portion 41b corresponding to a
size of igniter 40 at a portion largest in outer shape of agent
loaded portion 41. With the construction as such, if unexpected
breakage should occur in holding portion 30, igniter 40 could be
prevented from passing through opening 15 and jumping out of the
housing due to increase in internal pressure in combustion chamber
60, and a safe operation of gas generator 1A would be ensured.
[0108] FIG. 5 is a schematic diagram of an area in the vicinity of
the igniter of the gas generator according to a first variation
based on the present embodiment described above. In addition, FIG.
6A is a plan view of the holding portion of the gas generator
according to a second variation based on the present embodiment
described above, and FIG. 6B is a bottom view of the igniter. A
construction of the gas generator according to the first and second
variations based on the present embodiment will now be described
with reference to these FIGS. 5, 6A, and 6B.
[0109] As shown in FIG. 5, the gas generator according to the first
variation is different from gas generator 1A in the present
embodiment described above in a shape of locking pawl portion 34a
serving as the locking portion provided in holding portion 30.
Specifically, gas generator 1A in the present embodiment described
above has adopted such a construction that a plurality of locking
pawl portions 34a are provided in holding wall portion 34 provided
in inner coating portion 31 of holding portion 30, however, in the
gas generator according to the present first variation, locking
pawl portion 34a is formed integrally so as to annularly
continuously extend along the circumferential direction.
[0110] With the construction as such, locking pawl portion 34a and
holding wall portion 34 elastically deform, so that igniter 40 can
be inserted in accommodation recess portion 35 of holding portion
30 and igniter 40 can be held by holding portion 30 in a stable
manner after insertion.
[0111] On the other hand, as shown in FIGS. 6A and 6B, the gas
generator according to the second variation is different from gas
generator 1A in the present embodiment described above in a shape
of insertion hole 37a serving as the first rotation prevention
mechanism provided in coupling portion 33 of holding portion 30.
Specifically, in gas generator 1A in the present embodiment
described above, insertion hole 37a provided in coupling portion 33
of holding portion 30 is formed from a pair of holes in a perfect
circle shape when viewed two-dimensionally in correspondence with a
pair of terminal pins 42 of igniter 40, however, in the gas
generator according to the present second variation, an insertion
hole 37b is formed from a single hole in an oblong shape when
viewed two-dimensionally in correspondence with a pair of terminal
pins 42 of igniter 40.
[0112] In a case of such a construction as well, by inserting a
pair of terminal pins 42 in single insertion hole 37b, positioning
of igniter 40 with respect to holding portion 30 can readily be
achieved and igniter 40 can be prevented from rotating relative to
holding portion 30 after assembly.
Embodiment 2
[0113] FIG. 7 is a schematic diagram of a gas generator in
Embodiment 2 of the present invention. In addition, FIG. 8A is a
plan view of the holding portion of the gas generator in the
present embodiment, and FIG. 8B is a bottom view of the igniter. A
construction of a gas generator 1B in the present embodiment will
be described below with reference to these FIGS. 7, 8A, and 8B.
[0114] As shown in FIG. 7, gas generator 1B in the present
embodiment is different from gas generator 1A in Embodiment 1 of
the present invention described above in a shape of coupling
portion 33 of holding portion 30. Specifically, in gas generator 1B
in the present embodiment, an insertion hole 38 provided in
coupling portion 33 is not in a shape corresponding to a shape of a
pair of terminal pins 42 of igniter 40 but it is formed from a
single hole in a larger perfect circle shape when viewed
two-dimensionally. Therefore, insertion hole 38 does not have a
function as the first rotation prevention mechanism.
[0115] On the other hand, as shown in FIGS. 8A and 8B, in gas
generator 1B in the present embodiment, a part of a circumferential
surface of an overhang portion of lower cover 44 of igniter 40 is
formed from a flat surface 44d1 and a part of the inner
circumferential surface of holding wall portion 34 defining
accommodation recess portion 35 of holding portion 30 accommodating
igniter 40 is formed from a flat surface 34d in a shape
corresponding to flat surface 44d1. Namely, flat surface 34d
provided in holding wall portion 34 corresponds to the first
rotation prevention mechanism.
[0116] Therefore, in the case of gas generator 1B in the present
embodiment as well, by inserting igniter 40 in holding portion 30
such that flat surface 44d1 provided in igniter 40 and flat surface
34d provided in holding portion 30 meet each other, positioning of
igniter 40 with respect to holding portion 30 can readily be
achieved and igniter 40 can be prevented from rotating relative to
holding portion 30 after assembly.
[0117] FIG. 9A is a plan view of the holding portion of the gas
generator according to a variation based on the present embodiment,
and FIG. 9B is a bottom view of the igniter. A construction of the
gas generator according to the variation based on the present
embodiment will now be described with reference to these FIGS. 9A
and 9B.
[0118] As shown in FIGS. 9A and 9B, the gas generator according to
the present variation is different from gas generator 1B in the
present embodiment described above in a position where a flat
surface serving as the first rotation prevention mechanism provided
in holding portion 30 is provided. Specifically, in the gas
generator according to the present variation, a part of a
circumferential surface of a portion located at a lowermost end of
lower cover 44 of igniter 40 is formed from a flat surface 44d2,
and a part of the inner circumferential surface of coupling portion
33 of holding portion 30 is formed from a flat surface 33d in a
shape corresponding to flat surface 44d2. Namely, flat surface 33d
provided in coupling portion 33 corresponds to the first rotation
prevention mechanism.
[0119] In the case of such a construction as well, by inserting
igniter 40 in holding portion 30 such that flat surface 44d2
provided in igniter 40 and flat surface 33d provided in holding
portion 30 meet each other, positioning of igniter 40 with respect
to holding portion 30 can readily be achieved and igniter 40 can be
prevented from rotating relative to holding portion 30 after
assembly.
Embodiment 3
[0120] FIG. 10 is a schematic diagram of a gas generator in
Embodiment 3 of the present invention. A construction of a gas
generator 1C in the present embodiment will be described below with
reference to this FIG. 10.
[0121] As shown in FIG. 10, gas generator 1C in the present
embodiment is different from gas generator 1A in Embodiment 1 of
the present invention described above in a surface shape of
protruding cylindrical portion 13 provided in lower shell 10.
Specifically, in gas generator 1C in the present embodiment, a
plurality of recess portions 16 are provided in a surface of
protruding cylindrical portion 13 located on the side of combustion
chamber 60.
[0122] The plurality of recess portions 16 are in a shape not
continuously going around protruding cylindrical portion 13 at
least along the circumferential direction (that is, a shape which
is not an annular groove), and they are formed, for example, by
being formed simultaneously with press-working of lower shell 10 or
by providing impressions in the surface after press-working. In
addition, the plurality of recess portions 16 provided in lower
shell 10 are buried in inner coating portion 31 of holding portion
30 which is the resin-molded portion, and securing to lower shell
10 is achieved also in that portion.
[0123] With the construction as such, since a margin for securing
between lower shell 10 and holding portion 30 can further be made
greater, force of securing holding portion 30 to lower shell 10
improves, so that occurrence of peel-off at the interface portion
between lower shell 10 and holding portion 30 can be prevented. In
addition, even when force of securing holding portion 30 to lower
shell 10 decreases, the plurality of recess portions 16 provided in
lower shell 10 also function as a second rotation prevention
mechanism preventing holding portion 30 from rotating relative to
lower shell 10.
[0124] Though a case where a plurality of recess portions 16 are
provided in a surface of protruding cylindrical portion 13 located
on the side of combustion chamber 60 (that is, a surface coated
with inner coating portion 31) has been exemplified above, a
plurality of recess portions 16 may be provided in a surface of
protruding cylindrical portion 13 located on an outer side (that
is, a surface coated with outer coating portion 32), the number of
recess portions 16 may be one, or in addition, the same effect can
be obtained also by providing a through hole or a projection
portion in protruding cylindrical portion 13 instead of a recess
portion.
Embodiment 4
[0125] FIG. 11 is a schematic diagram of a gas generator in
Embodiment 4 of the present invention. FIG. 12 is a schematic
diagram of an area in the vicinity of the igniter of the gas
generator in the present embodiment. In addition, FIG. 13 is a
schematic diagram for illustrating a structure for assembly and a
procedure for assembly of the igniter of the gas generator in the
present embodiment. A structure for assembly, a procedure for
assembly, and the like of igniter 40 of a gas generator 1D in the
present embodiment will be described below with reference to these
FIGS. 11 to 13.
[0126] As shown in FIGS. 11 to 13, gas generator 1D in the present
embodiment is common to gas generator 1A in Embodiment 1 of the
present invention described above in that lower cover 44 which is a
part of igniter 40 is held by holding portion 30 while it is fitted
in accommodation recess portion 35 provided in holding portion 30,
however, it is different from gas generator 1A in Embodiment 1 of
the present invention described above in a specific structure of
holding portion 30 and igniter 40.
[0127] More specifically, as shown in FIGS. 11 to 13, holding wall
portion 34 having an annular shape defining accommodation recess
portion 35 of holding portion 30 has a plurality of locking hole
portions 34b provided to align along a circumferential direction at
positions intermediate in a vertical direction. The plurality of
locking hole portions 34b are sites corresponding to the locked
portion for fixing igniter 40 to holding portion 30, which are
integrally provided simultaneously with other sites of holding
portion 30 at the time of injection molding of holding portion 30.
It is noted that holding wall portion 34 itself is elastically
deformable.
[0128] On the other hand, lower cover 44 of igniter 40 has a
plurality of locking protruding portions 44b provided to protrude
outward in a circumferential surface at a site of which outer shape
is formed to be greater than agent loaded portion 41 (that is, a
site extending radially outward), and the plurality of locking
protruding portions 44b correspond to the locking portion for
fixing igniter 40 to holding portion 30. The plurality of locking
protruding portions 44b are provided to align along the
circumferential direction in correspondence with locking hole
portions 34b provided in holding portion 30.
[0129] During assembly, as shown in FIG. 13, while holding portion
30 formed from the resin-molded portion is formed in advance by
injection molding in bottom plate portion 11 of lower shell 10 and
sealing member 50 is accommodated within accommodation recess
portion 35 of holding portion 30, igniter 40 is inserted in
accommodation recess portion 35 from above that is, the side of top
plate portion 21 after assembly). Here, a pair of terminal pins 42
of igniter 40 is inserted in a pair of insertion holes 37a provided
in coupling portion 33 of holding portion 30.
[0130] Here, locking protruding portions 44b of igniter 40 come in
contact with holding wall portion 34 of holding portion 30. As
described above, however, since holding wall portion 34 is
elastically deformable, holding wall portion 34 retracts radially
outward, so that lower cover 44 of igniter 40 can be inserted in
accommodation recess portion 35.
[0131] Then, after igniter 40 is inserted in holding portion 30,
locking protruding portions 44b are fitted in locking hole portions
34b so that holding wall portion 34 returns to its original shape
and locking protruding portions 44b are locked to locking hole
portions 34b. Thus, igniter 40 is fitted in accommodation recess
portion 35 while lower cover 44 thereof is accommodated in
accommodation recess portion 35 of holding portion 30, and thus
igniter 40 is held by holding portion 30.
[0132] In the case of gas generator 1D in the present embodiment
described above as well, an effect the same as in the case of gas
generator 1A in Embodiment 1 of the present invention described
above can be obtained. Namely, igniter 40 which is a part in which
an ignition agent or the like sensitively reactive to static
electricity, flame, or the like is loaded is not exposed to a
high-temperature and high-pressure environment during assembly and
safety during the assembly operations can be ensured. In addition,
since assembly of igniter 40 to holding portion 30 can be realized
through an operation only for inserting igniter 40 in holding
portion 30, a gas generator can very readily be manufactured.
[0133] FIG. 14 is a schematic diagram for illustrating a structure
for assembly and a procedure for assembly of the igniter of the gas
generator according to a variation based on the present embodiment.
A structure for assembly and a procedure for assembly of the
igniter of the gas generator according to the variation based on
the present embodiment will now be described with reference to this
FIG. 14.
[0134] As shown in FIG. 14, the gas generator according to the
present variation is different from gas generator 1D in the present
embodiment described above in a specific structure of holding
portion 30 and igniter 40.
[0135] More specifically, as shown in FIG. 14, holding wall portion
34 having an annular shape defining accommodation recess portion 35
of holding portion 30 has a plurality of locking protruding
portions 34c provided on an inner circumferential surface to align
along a circumferential direction at a position intermediate in a
vertical direction. The plurality of locking protruding portions
34c are sites corresponding to the locking portion for fixing
igniter 40 to holding portion 30, which are integrally provided
simultaneously with other sites of holding portion 30 at the time
of injection molding of holding portion 30. Therefore, the
plurality of locking protruding portions 34c are each elastically
deformable, and in addition, holding wall portion 34 itself is
elastically deformable.
[0136] On the other hand, lower cover 44 of igniter 40 has a
plurality of locking recess portions 44c in a circumferential
surface at a site of which outer shape is formed to be greater than
agent loaded portion 41 (that is, a site extending radially
outward), and the plurality of locking recess portions 44c
correspond to the locked portion for fixing igniter 40 to holding
portion 30. The plurality of locking recess portions 44c are
provided to align along the circumferential direction in
correspondence with locking protruding portions 34c provided in
holding portion 30.
[0137] During assembly, as shown in FIG. 14, while holding portion
30 formed from the resin-molded portion is formed in advance by
injection molding in bottom plate portion 11 of lower shell 10 and
sealing member 50 is accommodated within accommodation recess
portion 35 of holding portion 30, igniter 40 is inserted in
accommodation recess portion 35 from above (that is, the side of
top plate portion 21 after assembly). Here, a pair of terminal pins
42 of igniter 40 is inserted in a pair of insertion holes 37a
provided in coupling portion 33 of holding portion 30.
[0138] Here, locking protruding portions 34c of holding portion 30
come in contact with the inclined lower surface of lower cover 44
of igniter 40. As described above, however, since locking
protruding portions 34c and holding wall portion 34 are elastically
deformable, locking protruding portions 34c and holding wall
portion 34 retract radially outward, so that lower cover 44 of
igniter 40 can be inserted in accommodation recess portion 35.
[0139] Then, after igniter 40 is inserted in holding portion 30,
locking protruding portions 34c are fitted in locking recess
portions 44c so that locking protruding portions 34c and holding
wall portion 34 return to their original shapes and locking
protruding portions 34c are locked to locking recess portions 44c.
Thus, igniter 40 is fitted in accommodation recess portion 35 while
lower cover 44 thereof is accommodated in accommodation recess
portion 35 of holding portion 30, and thus igniter 40 is held by
holding portion 30.
[0140] Therefore, in the case of such a construction as well, an
effect the same as in the case of gas generator 1D in the present
embodiment described above can be obtained.
Embodiment 5
[0141] FIG. 15 is a schematic diagram of a gas generator in
Embodiment 5 of the present invention. FIG. 16 is a schematic
diagram of an area in the vicinity of the igniter of the gas
generator in the present embodiment. FIG. 17 is a schematic diagram
for illustrating a structure for assembly and a procedure for
assembly of the igniter of the gas generator in the present
embodiment. In addition, FIG. 18A is a plan view of the holding
portion of the gas generator in the present embodiment, and FIG.
18B is a bottom view of the igniter. A structure for assembly, a
procedure for assembly, and the like of igniter 40 of a gas
generator 1E in the present embodiment will be described below with
reference to these FIGS. 15 to 17 and FIGS. 18A and 18B.
[0142] As shown in FIGS. 15 to 17 and FIGS. 18A and 18B, gas
generator 1E in the present embodiment is different from gas
generator 1D in Embodiment 4 of the present invention described
above in a shape of a cover which is a part of igniter 40.
Specifically, in gas generator 1E in the present embodiment, an
upper cover 45 of igniter 40 is not in a shape covering a part of
terminal pin 42 and base portion 41b of agent loaded portion 41,
but in a shape covering igniter cup 41a of agent loaded portion
41.
[0143] More specifically, upper cover 45 has a cup-shaped cap
portion 45a having an opening at a lower end, which covers a
circumferential surface and an upper surface of igniter cup 41a,
and includes at its lower end, a site in an annular shape of which
outer shape is formed to significantly be greater than agent loaded
portion 41 (that is, a site extending radially outward). A
plurality of locking protruding portions 45b protruding outward are
provided in the circumferential surface of the site, and the
plurality of locking protruding portions 45b correspond to the
locking portion for fixing igniter 40 to holding portion 30. The
plurality of locking protruding portions 45b are provided to align
along the circumferential direction in correspondence with locking
hole portions 34b provided in holding portion 30.
[0144] During assembly, as shown in FIG. 17, while holding portion
30 formed from the resin-molded portion is formed in advance by
injection molding in bottom plate portion 11 of lower shell 10,
upper cover 45 is attached in advance to agent loaded portion 41 to
construct igniter 40, and sealing member 50 is accommodated within
accommodation recess portion 35 of holding portion 30, igniter 40
is inserted in accommodation recess portion 35 from above (that is,
the side of top plate portion 21 after assembly). Here, a pair of
terminal pins 42 of igniter 40 is inserted in a pair of insertion
holes 37b provided in coupling portion 33 of holding portion
30.
[0145] Here, locking protruding portions 45b provided in upper
cover 45 of igniter 40 come in contact with holding wall portion 34
of holding portion 30. Holding wall portion 34, however, is
elastically deformable, and therefore holding wall portion 34
retracts radially outward, so that upper cover 45 of igniter 40 can
be inserted in accommodation recess portion 35.
[0146] Then, after igniter 40 is inserted in holding portion 30,
locking protruding portions 45b are fitted in locking hole portions
34b so that holding wall portion 34 returns to its original shape
and locking protruding portions 45b are locked to locking hole
portions 34b. Thus, igniter 40 is fitted in accommodation recess
portion 35 while upper cover 45 thereof is accommodated in
accommodation recess portion 35 of holding portion 30, and thus
igniter 40 is held by holding portion 30. It is noted that, prior
to attaching upper cover 45 to agent loaded portion 41, igniter 40
may be inserted in accommodation recess portion 35 of holding
portion 30 and thereafter upper cover 45 may be attached to holding
portion 30, to thereby simultaneously attach upper cover 45 to
agent loaded portion 41.
[0147] In the case of gas generator 1E in the present embodiment
described above as well, an effect the same as in the case of gas
generator 1D in Embodiment 4 of the present invention described
above can be obtained. Namely, igniter 40 which is a part in which
an ignition agent or the like sensitively reactive to static
electricity, flame, or the like is loaded is not exposed to a
high-temperature and high-pressure environment during assembly and
safety during the assembly operations can be ensured. In addition,
since assembly of igniter 40 to holding portion 30 can be realized
through an operation only for inserting igniter 40 in holding
portion 30, a gas generator can very readily be manufactured.
[0148] It is noted that gas generator 1E in the present embodiment
is constructed such that base portion 41b of igniter 40 is not
covered with upper cover 45. Therefore, a flexion portion provided
at an end portion of terminal pin 42 on the side of base portion
41b (that is, a root portion) is exposed in a state before assembly
to holding portion 30.
[0149] Then, in gas generator 1E in the present embodiment, as
shown in FIGS. 18A and 18B, in order to conform to a shape of a
jutting portion 42b1 of terminal pin 42, insertion hole 37b
provided in coupling portion 33 of holding portion 30 is formed
from an oblong shaped hole asymmetric when viewed
two-dimensionally, where a retracting surface 37b1 is formed.
[0150] Specifically, as insertion hole 37b provided in holding
portion 30 is provided with retracting surface 37b1 described
above, a site allowing reception of jutting portion 42b1 which is a
flexion portion of terminal pin 42 is provided in a portion facing
accommodation recess portion 35 and the site is provided only at a
prescribed position in a circumferential direction around a central
axis of insertion hole 37b1.
[0151] Here, during assembly, in a case where an orientation of
igniter 40 matches with an orientation of insertion hole 37b1
provided in holding portion 30, igniter 40 can smoothly be inserted
into a position where a bottom surface of base portion 41b of
igniter 40 comes in contact with a bottom surface of accommodation
recess portion 35, so that locking of locking protruding portions
45b described above to locking hole portions 34b can be achieved
and thus igniter 40 is held by holding portion 30.
[0152] On the other hand, FIG. 19 is a diagram showing a state in a
case where the igniter has been inserted in an incorrect
orientation in the gas generator in the present embodiment. As
shown in FIG. 19 during assembly, in a case where an orientation of
igniter 40 does not match with an orientation of insertion hole
37b1 provided in holding portion 30, jutting portion 42b1 of
terminal pin 42 comes in contact with and interferes with the
bottom surface of accommodation recess portion 35 and further
insertion becomes impossible. Then, base portion 41 of igniter 40
floats above the bottom surface of accommodation recess portion 35
by a shown height h, which leads to failure of locking protruding
portions 45b described above in reaching locking hole portions 34
and failure in fixing of igniter 40 to holding portion 30.
[0153] Therefore, with the construction as above, occurrence of a
defective condition due to insertion of igniter 40 in an incorrect
orientation during assembly can be prevented.
[0154] FIG. 20 is a schematic diagram of a gas generator according
to a first variation based on the present embodiment, and FIG. 21
is a schematic diagram for illustrating a structure for assembly
and a procedure for assembly of the igniter of the gas generator
according to the first variation. A structure for assembly, a
procedure for assembly, and the like of the gas generator according
to the first variation based on the present embodiment will now be
described with reference to these FIGS. 20 and 21.
[0155] As shown in FIGS. 20 and 21, a gas generator 1E' according
to the present first variation is different from gas generator 1E
in the present embodiment described above in a specific structure
of holding portion 30. More specifically, in gas generator 1E in
the present embodiment described above, insertion hole 37b provided
in coupling portion 33 of holding portion 30 has been formed from a
single hole in a substantially oblong shape when viewed
two-dimensionally in correspondence with a pair of terminal pins 42
of igniter 40, whereas in gas generator 1E' according to the
present first variation, insertion hole 37a is formed from a pair
of holes in a substantially perfect circle shape when viewed
two-dimensionally in correspondence with the pair of terminal pins
42 of igniter 40.
[0156] Here, in order to conform to a shape of a jutting portion of
terminal pin 42, each of the pair of insertion holes 37a is
provided with a retracting surface 37a1, so that a site allowing
reception of the jutting portion which is a flexion portion of
terminal pin 42 is provided in a portion facing accommodation
recess portion 35 and the site is provided only at a prescribed
position in a circumferential direction around a central axis of
each insertion hole 37a1.
[0157] Here, during assembly, in a case where an orientation of
igniter 40 matches with an orientation of insertion hole 37a1
provided in holding portion 30, igniter 40 can smoothly be inserted
into a position where a bottom surface of base portion 41b of
igniter 40 comes in contact with a bottom surface of accommodation
recess portion 35, so that locking of locking protruding portions
45b described above to locking hole portions 34b can be achieved
and thus igniter 40 is held by holding portion 30.
[0158] On the other hand, FIG. 22 is a diagram showing a state in a
case where the igniter has been inserted in an incorrect
orientation in the gas generator according to the first variation
based on the present embodiment. As shown in FIG. 22, during
assembly, in a case where an orientation of igniter 40 does not
match with an orientation of insertion hole 37a1 provided in
holding portion 30, both or one of the jutting portions of the pair
of terminal pins 42 come(s) in contact with and interfere(s) with
the bottom surface of accommodation recess portion 35 and further
insertion becomes impossible. Then, base portion 41 of igniter 40
floats above the bottom surface of accommodation recess portion 35
by shown height h, which leads to failure of locking protruding
portions 45b described above in reaching locking hole portions 34b
and failure in fixing of igniter 40 to holding portion 30.
[0159] Therefore, with such a construction as well, occurrence of a
defective condition due to insertion of igniter 40 in an incorrect
orientation during assembly can be prevented.
[0160] It is noted that, in the case of the construction as in the
present first variation, since a part of coupling portion 33 of
holding portion 30 formed from the resin-molded portion is located
at a portion of igniter 40 located between the pair of terminal
pins 42, a fluid resin material flows well while holding portion 30
is formed by injection molding and high moldability can also be
ensured.
[0161] FIG. 23 is a schematic diagram for illustrating a structure
for assembly and a procedure for assembly of the igniter of a gas
generator according to a second variation based on the present
embodiment. A structure for assembly and a procedure for assembly
of the igniter of the gas generator according to the second
variation based on the present embodiment will now be described
with reference to this FIG. 23.
[0162] As shown in FIG. 23, the gas generator according to the
present second variation is different from gas generator 1E in the
present embodiment described above in a specific structure of
holding portion 30 and igniter 40.
[0163] More specifically, as shown in FIG. 23, holding wall portion
34 having an annular shape defining accommodation recess portion 35
of holding portion 30 has a plurality of locking protruding
portions 34c provided on an inner circumferential surface to align
along a circumferential direction at a position intermediate in a
vertical direction. The plurality of locking protruding portions
34c are sites corresponding to the locking portion for fixing
igniter 40 to holding portion 30, which are integrally provided
simultaneously with other sites of holding portion 30 at the time
of injection molding of holding portion 30. Therefore, the
plurality of locking protruding portions 34c are all elastically
deformable and holding wall portion 34 itself is elastically
deformable.
[0164] On the other hand, upper cover 45 of igniter 40 has a
plurality of locking recess portions 45c in a circumferential
surface at a site in an annular shape of which outer shape is
formed to be significantly greater than agent loaded portion 41
(that is, a site extending radially outward), and the plurality of
locking recess portions 45c correspond to the locked portion for
fixing igniter 40 to holding portion 30. The plurality of locking
recess portions 45c are provided to align along the circumferential
direction in correspondence with locking protruding portions 34c
provided in holding portion 30.
[0165] During assembly, as shown in FIG. 23, while holding portion
30 formed from the resin-molded portion is formed in advance by
injection molding in bottom plate portion 11 of lower shell 10,
upper cover 45 is attached in advance to agent loaded portion 41 to
construct igniter 40, and sealing member 50 is accommodated within
accommodation recess portion 35 of holding portion 30, igniter 40
is inserted in accommodation recess portion 35 from above (that is,
the side of top plate portion 21 after assembly). Here, a pair of
terminal pins 42 of igniter 40 is inserted in a pair of insertion
holes 37a provided in coupling portion 33 of holding portion
30.
[0166] Here, locking protruding portions 34c of holding portion 30
come in contact with the inclined lower surface of upper cover 45
of igniter 40. As described above, however, since locking
protruding portions 34c and holding wall portion 34 are elastically
deformable, locking protruding portions 34c and holding wall
portion 34 retract radially outward, so that upper cover 45 of
igniter 40 can be inserted in accommodation recess portion 35.
[0167] Then, after igniter 40 is inserted in holding portion 30,
locking protruding portions 34c are fitted in locking recess
portions 45c so that locking protruding portions 34c and holding
wall portion 34 return to their original shapes and locking
protruding portions 34c are locked to locking recess portions 45c.
Thus, igniter 40 is fitted in accommodation recess portion 35 while
upper cover 45 thereof is accommodated in accommodation recess
portion 35 of holding portion 30, and thus igniter 40 is held by
holding portion 30. It is noted that, prior to attaching upper
cover 45 to agent loaded portion 41, igniter 40 may be inserted in
accommodation recess portion 35 of holding portion 30 and
thereafter upper cover 45 may be attached to holding portion 30, to
thereby simultaneously attach upper cover 45 to agent loaded
portion 41.
[0168] Therefore, in the case of such a construction as well, an
effect the same as in the case of gas generator 1E in the present
embodiment described above can be obtained.
Embodiment 6
[0169] FIG. 24 is a schematic diagram of a gas generator in
Embodiment 6 of the present invention. A structure for assembly, a
procedure for assembly, and the like of igniter 40 of a gas
generator 1F in the present embodiment will be described below with
reference to this FIG. 24.
[0170] As shown in FIG. 24, gas generator 1F in the present
embodiment is common to gas generator 1A in Embodiment 1 of the
present invention described above in that lower cover 44 which is a
part of igniter 40 is held by holding portion 30 while it is fitted
in accommodation recess portion 35 provided in holding portion 30.
Gas generator 1F, however, is different from gas generator 1A in
Embodiment 1 of the present invention described above in a specific
structure of holding portion 30 and igniter 40 or a specific
structure for holding portion 30 to hold igniter 40.
[0171] More specifically, as shown in FIG. 24, in gas generator 1F
in the present embodiment, a locking mechanism is not provided in
holding portion 30 and igniter 40, but instead an adhesive is
applied between a surface of accommodation recess portion 35 of
holding portion 30 and a surface of lower cover 44 of igniter 40
opposed thereto, so that holding portion 30 holds igniter 40 by
means of an adhesive layer 52 formed by curing of the adhesive.
Here, if an adhesive poor in hygroscopicity is employed as the
adhesive, adhesive layer 52 itself formed as a result of curing of
the adhesive functions as a sealing member. Therefore, by filling a
gap between lower cover 44 of igniter 40 and accommodation recess
portion 35 of holding portion 30 with adhesive layer 52, it is not
necessary to interpose a sealing member formed from a separate
member such as an O ring, which also contributes to reduction in
the number of parts.
[0172] For the adhesive above, an adhesive containing a resin
material excellent in heat resistance, durability, corrosion
resistance, and the like after curing is suitably selected and made
use of, and for example, a cyanoacrylate-based resin or a
silicone-based resin is particularly suitably made use of as the
resin material. In addition, for the resin material, other than the
resin materials described above, a phenol-based resin, an
epoxy-based resin, a melamine-based resin, a urea-based resin, a
polyester-based resin, an alkyd-based resin, a polyurethane-based
resin, a polyimide-based resin, a polyethylene-based resin, a
polypropylene-based resin, a polyvinyl chloride-based resin, a
polystyrene-based resin, a polyvinyl acetate-based resin, a
polytetrafluoroethylene-based resin, an acrylonitrile butadiene
styrene-based resin, an acrylonitrile styrene-based resin, an
acryl-based resin, a polyamide-based resin, a polyacetal-based
resin, a polycarbonate-based resin, a polyphenylene ether-based
resin, a polybutylene terephthalate-based resin, a polyethylene
terephthalate-based resin, a polyolefin-based resin, a
polyphenylene sulfide-based resin, a polysulfone-based resin, a
polyether sulfone-based resin, a polyarylate-based resin, a
polyether ether ketone-based resin, a polyamide imide-based resin,
a liquid crystal polymer, and the like can be made use of.
[0173] During assembly, while holding portion 30 formed from the
resin-molded portion is formed in advance by injection molding in
bottom plate portion 11 of lower shell 10 and an adhesive is
applied to the surface of accommodation recess portion 35 of
holding portion 30, igniter 40 is inserted in accommodation recess
portion 35 from above (that is, the side of top plate portion 21
after assembly). Here, a pair of terminal pins 42 of igniter 40 is
inserted in a pair of insertion holes 37a provided in coupling
portion 33 of holding portion 30.
[0174] Thus, igniter 40 is fitted in accommodation recess portion
35 while lower cover 44 thereof is accommodated in accommodation
recess portion 35 of holding portion 30. As the adhesive is cured,
holding portion 30 holds igniter 40. It is noted that the adhesive
may be applied to lower cover 44 of igniter 40.
[0175] In the case of gas generator 1F in the present embodiment
described above as well, an effect the same as in the case of gas
generator 1A in Embodiment 1 of the present invention described
above can be obtained. Namely, igniter 40 which is a part in which
an ignition agent or the like sensitively reactive to static
electricity, flame, or the like is loaded is not exposed to a
high-temperature and high-pressure environment during assembly and
safety during the assembly operations can be ensured. In addition,
since assembly of igniter 40 to holding portion 30 can be realized
through an operation only for inserting igniter 40 in holding
portion 30, a gas generator can very readily be manufactured.
Embodiment 7
[0176] FIG. 25 is a schematic diagram of a gas generator in
Embodiment 7 of the present invention. A structure for assembly, a
procedure for assembly, and the like of igniter 40 of a gas
generator 1G in the present embodiment will be described below with
reference to this FIG. 25.
[0177] As shown in FIG. 25, gas generator 1G in the present
embodiment is combination of a structure for locking igniter 40 to
holding portion 30 which has been adopted in gas generator 1A in
Embodiment 1 of the present invention described above with a
structure for holding portion 30 to hold igniter 40 which has been
adopted in gas generator 1F in Embodiment 6 of the present
invention described above.
[0178] Namely, in gas generator 1G in the present embodiment,
locking pawl portion 34a is provided at a tip end of holding wall
portion 34, so that lower cover 44 of igniter 40 is locked by
locking pawl portion 34a after assembly. In addition, an adhesive
is applied between a surface of accommodation recess portion 35 of
holding portion 30 and a surface of lower cover 44 of igniter 40
opposed thereto, so that holding portion 30 holds igniter 40 after
assembly by means of adhesive layer 52 formed by curing of the
adhesive.
[0179] In the case of gas generator 1G in the present embodiment
described above as well, an effect the same as in the case of gas
generator 1A in Embodiment 1 of the present invention described
above can be obtained. Namely, igniter 40 which is a part in which
an ignition agent or the like sensitively reactive to static
electricity, flame, or the like is loaded is not exposed to a
high-temperature and high-pressure environment during assembly and
safety during the assembly operations can be ensured. In addition,
since assembly of igniter 40 to holding portion 30 can be realized
through an operation only for inserting igniter 40 in holding
portion 30, a gas generator can very readily be manufactured.
Moreover, in the case of gas generator 1G in the present
embodiment, as in the case of gas generator 1F in Embodiment 6 of
the present invention described above, it is not necessary to
interpose a sealing member formed from a separate member such as an
O ring between igniter 40 and holding portion 30, and therefore an
effect that the number of parts can be reduced is also
obtained.
Embodiment 8
[0180] FIG. 26 is an enlarged view of a main portion of a gas
generator in Embodiment 8 of the present invention. A gas generator
1H in the present embodiment will be described below with reference
to this FIG. 26.
[0181] As shown in FIG. 26, gas generator 1H in the present
embodiment is different from gas generator 1D in Embodiment 4 of
the present invention described above in a specific shape of
locking protruding portion 44b serving as the locking portion.
[0182] More specifically, each of a plurality of locking protruding
portions 44b provided in lower cover 44 of igniter 40 has a groove
portion 44b1 extending in a circumferential direction, in a portion
in a main surface on a side to be locked to locking hole portion
34b serving as the locked portion (that is, the upper surface of
locking protruding portion 44b in the figure) in correspondence
with a root of locking protruding portion 44b.
[0183] Groove portion 44b1 is provided such that locking protruding
portion 44b is more readily elastically deformable at the time of
contact of locking protruding portion 44b with holding wall portion
34 during assembly, and provided to prevent plastic deformation of
locking protruding portion 44b during assembly.
[0184] In the case of gas generator 1H in the present embodiment
described above as well, an effect the same as in the case of gas
generator 1D in Embodiment 4 of the present invention described
above can be obtained.
[0185] In addition, by adopting the construction above, the root
portion of locking protruding portion 44b is greatly bent at the
time of assembly of igniter 40, so that locking protruding portion
44b readily elastically deforms and smooth assembly of igniter 40
to holding portion 30 can be achieved. In addition, concentration
of compressive stress at the root portion of locking protruding
portion 44b and resultant plastic deformation can be prevented, and
stable assembly of igniter 40 to holding portion 30 can be
achieved.
[0186] Namely, by adopting the construction above, not only
assembly operations are facilitated, but also locking protruding
portion 44b more readily returns to its original shape after
assembly. Therefore, variation in accuracy in position of assembly
caused by plastic deformation of locking protruding portion 44b can
be suppressed, and such defective conditions as wobbling of igniter
40 after assembly or insufficient assembly strength can effectively
be prevented.
[0187] In Embodiments 1 to 8 and variations thereof of the present
invention described above, a case where a lower shell is formed
from a press-formed product formed by press-working one
plate-shaped member made of metal has been exemplified, however,
limitation thereto is not necessarily intended. A lower shell
formed by combination of press-working and another type of working
(forging, drawing, cutting, or the like) may be employed, or a
lower shell formed only by another type of working may be
employed.
[0188] In addition, in Embodiments 1 to 8 and variations thereof of
the present invention described above, a case where an igniter of a
type in which an ignition agent and an enhancer agent are loaded in
an agent loaded portion has been employed as the igniter has been
exemplified, however, an igniter of a type what is called a squib
in which only an ignition agent is loaded in an agent loaded
portion may be employed instead.
[0189] Moreover, characteristic features of the gas generators
according to Embodiments 1 to 8 and variations thereof of the
present invention described above can naturally be combined with
one another within the scope allowable in light of the gist of the
present invention. Furthermore, a specific shape of a protruding
cylindrical portion provided in a lower shell described above, a
specific shape of a holding portion provided on the lower shell, a
shape of an igniter fitted in the holding portion, and the like can
also naturally be modified as appropriate.
[0190] Thus, each embodiment and a variation thereof above
disclosed herein are illustrative and non-restrictive in every
respect. The technical scope of the present invention is delimited
by the terms of the claims and is intended to include any
modifications within the scope and meaning equivalent to the terms
of the claims.
REFERENCE SIGNS LIST
[0191] 1A to 1H, 1E' gas generator; 10 lower shell; 11 bottom plate
portion; 12 circumferential wall portion; 13 protruding cylindrical
portion; 14 depression portion; 15 opening; 16 recess portion; 20
upper shell; 21 top plate portion; 22 circumferential wall portion;
23 gas discharge opening; 24 sealing member; 30 holding portion; 31
inner coating portion; 32 outer coating portion; 33 coupling
portion; 33d flat surface; 34 holding wall portion; 34a locking
pawl portion; 34b locking hole portion; 34c locking protruding
portion; 34d flat surface; 35 accommodation recess portion; 36
female connector portion; 37a, 37b, 38 insertion hole; 37a1, 37b1
retracting surface; 40 igniter; 41 agent loaded portion; 41a
igniter cup; 41b base portion; 42 terminal pin; 42b1 jutting
portion; 44 lower cover; 44b locking protruding portion; 44b1
groove portion; 44c locking recess portion; 44d1, 44d2 flat
surface; 45 upper cover; 45a cap portion; 45b locking protruding
portion; 45c locking recess portion; 50 sealing member, 52 adhesive
layer; 60 combustion chamber; 61 gas generating agent; 62
upper-side supporting member; 63 lower-side supporting member; 64
cushion material; and 70 filter.
* * * * *