U.S. patent application number 10/765940 was filed with the patent office on 2004-12-09 for parts of igniter.
Invention is credited to Harada, Hiroshi, Oda, Shingo, Shimizu, Nobuyoshi.
Application Number | 20040244624 10/765940 |
Document ID | / |
Family ID | 33493911 |
Filed Date | 2004-12-09 |
United States Patent
Application |
20040244624 |
Kind Code |
A1 |
Harada, Hiroshi ; et
al. |
December 9, 2004 |
Parts of igniter
Abstract
The present invention provides a simple manufacturing method of
parts of igniter which makes welding unnecessary. Electroconductive
pins 51 and 52 are pushed in through-holes 45 and 46 of a header
40, and a heat generating body 30 is penetrated by the
electroconductive pins 51 and 52. Thereafter, the heat generating
body 30 is fixed by crimping one end portions 51a and 52a of the
electroconductive pins 51 and 52.
Inventors: |
Harada, Hiroshi;
(Himeji-shi, JP) ; Oda, Shingo; (Himeji-shi,
JP) ; Shimizu, Nobuyoshi; (Ibo-gun, JP) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Family ID: |
33493911 |
Appl. No.: |
10/765940 |
Filed: |
January 29, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60445238 |
Feb 6, 2003 |
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Current U.S.
Class: |
102/202.9 |
Current CPC
Class: |
F42B 3/195 20130101;
F42B 3/103 20130101 |
Class at
Publication: |
102/202.9 |
International
Class: |
F42C 001/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2003 |
JP |
2003-24097 |
Claims
1. Parts of igniter including a header, a heat generating body and
a single or plural electroconductive pins, wherein the
electroconductive pin penetrates from the one surface of the header
to the other, and the heat generating body is sandwiched and held
between one end portion of the electroconductive pin on the header
one surface and the header surface.
2. Parts of igniter according to claim 1, wherein a portion of the
one end portion of the electroconductive pin which is opposite to
the header surface is flat and a portion of the one end portion of
the electroconductive pin which is not opposite to the header
surface is not flat, and the heat generating body is sandwiched and
held between the flat surface and the header surface.
3. Parts of igniter according to claim 1, wherein the one end
portion of the electrocoductive pin has a flange portion and the
heat generating body is sandwiched and held between the flange
portion and the header surface.
4. Parts of igniter according to claim 1, wherein the one end
portion of the electroconductive pin has a groove formed in a
radial direction, and the heat generating body is sandwiched and
held between the groove and the header surface.
5. Parts of igniter including a header, a heat generating body and
one or plural electroconductive pins, wherein the electroconductive
pin penetrates the header from one surface side thereof to the
other face side thereof, and the heat generating body is sandwiched
and held in one end portion of the electroconductive pin positioned
on the one surface side of the header.
6. Parts of igniter according to claim 1 or 5, wherein the heat
generating body is constituted such that a contacting portion
coming in contact with the one end portion of the electroconductive
pin and a heat generating portion generating heat due to an
electric current are formed integrally on a printed substrate.
7. Parts of igniter according to claim 6, wherein the heat
generating portion of the heat generating body is an. S-shaped one
formed by etching.
8. A method of manufacturing parts of igniter, comprising: a step
of placing a heat generating body on one surface of a header; a
step of causing an electroconductive pin to penetrate the header
from the one surface to the other surface thereof; and a holding
step of sandwiching the heat generating body between one end
portion of the electroconductive pin on the header one surface and
the header surface to fix the same.
9. A manufacturing method of parts of igniter according to claim 8,
wherein the step of causing the electroconductive pin to penetrate
comprises a step of causing the electroconductive pin to penetrate
both the heat generating body and the header.
10. A manufacturing method of parts of igniter according to claim 8
or 9, wherein the electroconductive pin is a rod like shaped one,
and the holding step comprises steps of deforming one end portion
of the electroconductive pin and of sandwiching the heat generating
body between the deformed one end portion and a header surface to
fix the same.
11. A manufacturing method of parts of igniter according to claim 8
or 9, wherein the electroconductive pin is a nail like shaped one
having a flange portion at one end portion, and the holding step
comprises a step of sandwiching the heat generating body between
the flange portion at the one end portion of the electroconductive
pin and a header surface to fix the same.
12. A manufacturing method of parts of igniter according to claim 8
or 9, wherein the electroconductive pin has a groove formed
radially on one end portion, and the holding step comprises a step
of sandwiching the heat generating body between the groove on the
one end portion of the electroconductive pin and a header surface
to fix the same.
13. A manufacturing method of parts of igniter according to claim 8
or 9, wherein an undulation is formed on a penetrating portion of
the electroconductive pin in the other surface side of the header
either before or after the holding step.
14. A method of manufacturing parts of igniter, comprising: a step
of causing an electroconductive pin, which has an engagement
portion with a heat generating body at one end portion, to
penetrate a header from one surface to the other surface; a step of
causing both ends of the heat generating body to be engaged with
the engagement portion of the electroconductive pin on the one
surface of the header; and a holding step of sandwiching the heat
generating body in the one end portion of the electroconductive pin
to fix the same by crimping the engagement portion of the
electroconductive pin.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates to parts of igniter used for
an igniter suitable for various kinds of gas generators for an air
bag and a method of manufacturing the same.
BACKGROUND ART
[0002] In various kinds of gas generators for an air bag, a
reliability of activation becomes considerably important element
from the viewpoint of safety assurance of a passenger. For this
reason, importance of an igniter which is actuated after collision
of a vehicle to ignite and burn a gas generating agent for
inflating an airbag is high.
[0003] The igniter includes electroconductive pins and a heat
generating body as constituent elements, in which the heat
generating body starts heat-generating by current flowing through
the conductive pins and a priming is burnt thereby so that the gas
generating agent is ignited and burnt through combustion of a
transfer charge arranged if required. Since such a course is taken,
it is required that an electric current flowing in the
electroconductive pins flows into the heat generating body reliably
in a first stage of actuation. The followings are known as the
prior arts relating to such an igniter.
[0004] JP-A 2001-235300 discloses a technique relating to an
invention concerning a method for welding bridge wires in a plug
for an electric igniter, in which a heat generating body is
spot-welded to end portions of electroconductive pins in the head.
A thin wire (wire diameter of 26 to 36 .mu.m) of an alloy including
nickel-chrome as a main component is used as a heat generating
body.
[0005] In the technique, since the heat generating body is
extremely thin, welding must be performed in such a state that a
welding terminal presses the heat generating body against an end
portion of the electroconductive pin perpendicularly. When a
mistake occurs in the welding, namely, a portion of the welding
electrode comes in contact with a header or the like, one portion
of a welding current flows through the header in a branching
manner, which causes welding failure between the heat generating
body and the electroconductive wire. Further, when an electric
current become excessive at a time of welding, the wire is melted
and when an electric current become short, welding becomes
insufficient.
[0006] If end portions of electrodes are disposed on one end
surface of a header (a part 11 shown in FIG. 1 of JP-A 2001-235300)
having a flat plane portion and the heat generating body is mounted
between the end portions on the same flat surface by welding or the
like, with a unflat mounting surface, there is such a risk that the
heat generating body may be disconnected. Therefore, polishing for
removing undulation or the like is required in general.
[0007] In the technique, since conditions for welding are directly
linked with a reliability of a product directly, management of a
welding electrode (management for replacement frequency, degree of
verticality or the like) and management of a welding current become
important.
[0008] JP-B No. 3175051 discloses an invention relating to an
electric ignition type initiator.
[0009] A heat generating resistance substrate 20 is provided on a
cylindrical glass hermetic 11, and through-holes 20a are formed at
positions corresponding to electroconductive pins 12. Further,
electroconductive areas 21 are provided on the substrate 20, and a
resistance element 22 is formed between the areas 21. Since the
electroconductive pins 12 and the electroconductive areas 21 have
been joined by solder or electrocoductive adhesion 23, it is
necessary to prepare the solder or electroconductive adhersion
separately. In particular, when joining is performed using a solder
or an electroconductive adhesion, there occurs a problem regarding
reliability of the joining. For example, when a joining surface is
dirty with, for example, oil, there occurs a risk that a solder may
be repelled and a joining force lowers, so that a joining failure
occurs due to repetitive stress caused by vibrations during a
vehicle driving.
[0010] JP-A 2001-194094 discloses an invention relating to a
detonating agent. According to FIG. 1 and FIG. 2, and descriptions
corresponding thereto, holes 22 and 23 are formed in a heat
generating portion (a flat plate resistance element) 17 formed on
an insulating substrate 16, and electrodes 12 and 13 penetrate the
holes. However, in the publication, there is not any disclosure
about a method for joining electroconductive metal regions 28 and
29 and the electrodes 12 and 13.
DISCLOSURE OF THE INVENTION
[0011] One object of the present invention is to provide parts of
igniter which, when applied to an igniter for a gas generator for
an air bag, can elevate an activation reliability of the igniter
and can improve a reliability as a product of a gas generator.
[0012] Another object of the present invention is to provide a
manufacturing method of parts of igniter, which can manufacture the
above-described parts of igniter by a simple method and at a low
cost.
[0013] The invention according to claim 1 provides, as a means for
solving the problem, parts of the igniter comprises a header,
heat-generating body and a single or plural electroconductive pin,
wherein the electoroconductive pin penetrates from one end surface
to the other of the header, and heat-generating body is interposed
to be fixed between a one end portion of the electroconductive pin
on the one surface of the header and a surface of the header.
[0014] The heat generating body may be one in which a heat
generating portion is formed on a proper substrate, as well as such
one as an alloy wire generating heat.
[0015] The number of electroconductive pins is at least one, and
two or three or more electroconductive pins can be used according
to a structure and a function of an igniter.
[0016] In the invention described in claim 1, by applying a method
of physically holding the heat generating body by using one end
portion of the electroconductive pin, as a holding means for the
heat generating body, use of a solder and an electroconductive
adhesion is made unnecessary so that a problem occurring when these
are used can be eliminated. Further, since complicated welding,
soldering or the like is made unnecessary, a manufacturing cost is
also reduced.
[0017] The invention described in claim 2 provides parts of igniter
described in claim 1, wherein a portion of the one end portion of
the electroconductive pin opposite to the header surface is flat
and a portion of the one end portion of the electroconductive pin
not opposite to the header surface is not flat, and the heat
generating body is sandwiched and held between the flat surface and
the header surface.
[0018] Since the portion opposite to the surface of the header is
flat, when the heat generating body is sandwiched between the flat
surface and the surface of the header, a holding force for the heat
generating body is elevated.
[0019] The invention described in claim 3 provides parts of igniter
described in claim 1, in which the one end portion of the
electrocoductive pin has a flange portion and the heat generating
body is sandwiched and held between the flange portion and the
header surface.
[0020] Since the flange is flat, at the time of interposing the
heat generating body between the flange portion and the surface of
the header, a holding force for the heat generating body is
elevated.
[0021] The invention described in claim 4 provides parts of igniter
described in claim 1, in which the one end portion of the
electroconductive pin has a groove formed in the radial direction,
and the heat generating body is sandwiched and held between the
groove and the header surface.
[0022] Since the heat generating body is sandwiched between the
groove and the surface of the header, a holding force for the heat
generating body is elevated. Further, the heat generating body is
simply fitted into the groove, so that it is also made easy to
position the heat generating body.
[0023] The invention described in claim 5 provides, as another
means for solving the problem, parts of igniter including a header,
a heat generating body and a single or plural electroconductive
pins, wherein the electroconductive pin penetrates the header from
one surface thereof to the other surface, and the heat generating
body is sandwiched and held in one end portion of the
electroconductive pin positioned on the one surface of the
header.
[0024] As well as an effect similar to that in the invention
described in claim 1 can be obtained, since the heat generating
body is sandwiched and held only in the one end portion of the
electroconductive pin, the heat generating body can be held without
being influenced by a shape or a surface condition of the
header.
[0025] The invention described in claim 6 provides parts of igniter
described in any one of claims 1 to 5, where the heat generating
body is constituted such that a contacting portion coming in
contact with the one end portion of the electroconductive pin and a
heat generating portion generating heat with an electric current
are formed integrally on a printed substrate.
[0026] By using such a printed substrate in this manner, formation
of the heat generating portion of the heat generating body can be
facilitated and a holding work for the heat generating body can be
facilitated, and additionally, disconnection in the heat generating
portion hardly occurs, as compared with the case of an alloy wire
welded and fixed as the heat generating body.
[0027] The invention described in claim 7 provides parts of igniter
described in claim 6, in which the heat generating portion of the
heat generating body is an S-shaped one formed by etching.
[0028] By forming the heat generating portion in the S-shape in
this manner, even if coefficients of thermal expansion of the
printed substrate and the heat generating portion are different
from each other, a deformation due to a difference in coefficient
of thermal expansion can be absorbed by the shape (the S-shape), so
that disconnection in the heat generating portion hardly
occurs.
[0029] The invention described in claim 8 provides, as another
means for solving the problem, a method of manufacturing parts of
igniter, comprising: a step of placing a heat generating body on
one surface of a header; a step of causing an electroconductive pin
to penetrate the header from the one surface to the other surface
thereof; and a holding step of sandwiching the heat generating body
between one end portion of the electroconductive pin on the one
surface of the header and a header surface to fix the same.
[0030] By applying the method of physically holding by means of the
one end portion of the electroconductive pin as a holding means for
the heat generating body in this manner, use of a welding method
and use of a solider and an electroconductive adhesion are made
unnecessary so that the problem caused when these are used can be
eliminated. Further, since complicated welding or soldering work or
the like becomes unnecessary, a manufacturing cost is reduced.
[0031] The invention described in claim 9 provides a manufacturing
method of parts of igniter described in claim 8, in which the step
of causing the electroconductive pin to penetrate is a step of
causing the electroconductive pin to penetrate both the heat
generating body and the header.
[0032] In addition to being capable of positioning of the
electroconductive pin and the heat generating body at once,
workability is also elevated so that a reliable fixation can be
achieved.
[0033] The invention described in claim 10 provides a manufacturing
method of parts of igniter described in claim 8 or 9, in which the
electroconductive pin is a rod like shaped one, and the holding
step comprises steps of deforming one end portion of the
electroconductive pin and of sandwiching the heat generating body
between the deformed one end portion and a header surface to fix
the same.
[0034] In case of a conventional welding method, soldering method
or the like, a difference occurs in a fixed state of the heat
generating body due to variations in welding condition or soldering
condition, the difference influences an electric connected state
directly, and it also influences a performance of a product.
However, in the above invention, since a method of fixing the heat
generating body by deforming the one end portion of the
electroconductive pin by means of crimping or crushing is adopted,
the electric connected state is stabilized without causing
variations in a fixed state, so that a performance of a product is
also stabilized.
[0035] The invention described in claim 11 provides a manufacturing
method of parts of igniter described in claim 8 or 9, in which the
electroconductive pin is a nail like shaped one having a flange
portion at one end portion, and the holding step is a step of
sandwiching the heat generating body between the flange portion at
the one end portion of the electroconductive pin and a header
surface to fix the same.
[0036] By using the nail like shaped electroconductive pin having
the flange portion at the one end portion, a fixing work for the
heat generating body is facilitated and the electric connected
state is stabilized without causing variations in a fixed state, so
that a performance of a product is also stabilized.
[0037] The invention described in claim 12 provides a manufacturing
method of parts of igniter described in claim 8 or claim 9, in
which the electroconductive pin has a groove formed in the radial
direction on one end portion, and the holding step comprises a step
of sandwiching the heat generating body between a groove in the one
end portion of the electroconductive pin and a header surface to
fix the same.
[0038] By using the electroconductive pin having the groove formed
in the one end portion thereof in the radial direction, a fixing
work for the heat generating body is facilitated, and the electric
connected state is stabilized without causing variations in a fixed
state, so that a performance of a product is also stabilized.
[0039] The invention described in claim 13 provides a manufacturing
method of parts of igniter described in any one of claims 8 to 12,
in which an undulation is formed on a penetrating portion of the
electroconductive pin in the other surface side of the header
either before or after the holding step.
[0040] By forming the undulation on the penetrating portion, the
electroconductive pin is prevented from falling off in the
direction opposite to the penetrating portion. When the undulation
is formed after the holding step, it is formed on only the
penetrating portion of the electroconductive pin, but when it is
formed before the holding step, not only the penetrating portion of
the electroconductive pin but also a portion thereof which exists
in the header can be formed with an undulation. If the undulation
is formed even on the portion of the electroconductive pin existing
inside the header in this manner, a falling-off preventing effect
for an electroconductive pin can be further elevated and a holding
force for the heat generating body is also elevated.
[0041] The invention described in claim 14 provides a method of
manufacturing parts of igniter, comprising: a step of causing an
electroconductive pin having an engagement portion with a heat
generating body at one end portion to penetrate a header from one
surface to the other surface; a step of causing both ends of the
heat generating body to be engaged with the engagement portion of
the electroconductive pin on the one surface of the header; and a
holding step of sandwiching the heat generating body in the one end
portion of the electroconductive pin to fix the same by crimping
the engagement portion of the electroconductive pin.
[0042] In addition to obtaining an effect similar to that in the
invention described in claim 8, since the heat generating body is
sandwiched and held only by the one end portion of the
electroconductive pin, the heat generating body can be held without
being influenced by a shape or a surface condition of the
header.
[0043] According to the parts of igniter and the manufacturing
method of the same, an electroconductive pin and a heat generating
body can be firmly connected to each other with a much simple
method without applying a welding method, a soldering method, an
adhesion method using an electroconductive adhesion to connect the
electroconductive pin and the heat generating body. Further, a
manufacturing cost can be reduced as compared with a case in which
the welding method, the soldering method, or the adhesion method
using an electroconductive adhesion is applied.
BRIEF DESCRIPTION OF THE DRAWINGS
[0044] FIG. 1 is a schematic vertical sectional view of an igniter
assembly including parts of igniter;
[0045] FIG. 2 is step diagrams showing one embodiment of a
manufacturing method of parts of igniter;
[0046] FIG. 3 is step diagrams showing another embodiment of a
manufacturing method of parts of igniter;
[0047] FIG. 4 is step diagrams showing another embodiment of a
manufacturing method of parts of igniter;
[0048] FIG. 5 is step diagrams showing another embodiment of a
manufacturing method of parts of igniter;
[0049] FIG. 6 is a step diagram showing an embodiment in which a
catching portion is different from that in FIG. 5;
[0050] FIG. 7 is step diagrams showing another embodiment of a
manufacturing method of parts of igniter; and
[0051] FIG. 8 is step diagrams of an embodiment in which a
pushing-in state of an electroconductive pin is different from that
in FIGS. 7.
EXPLANATION OF NUMERALS
[0052] 10 igniter assembly
[0053] 20 parts of igniter
[0054] 30 heat generating body
[0055] 40 header
[0056] 51, 52 electroconductive pin
PREFERRED EMBODIMENT OF THE INVENTION
[0057] (1) Embodiment 1
[0058] A first embodiment of the present invention will be
explained with reference to FIG. 1 and FIG. 2. FIG. 1 is a
schematic vertical sectional view of an igniter assembly 10
comprising parts of igniter 20, and FIGS. 2 are step diagrams
showing a manufacturing method (an assembling method) of the parts
of igniter 20.
[0059] An outer shape of the igniter assembly 10 can be adjusted
according to a gas generator for an air bag to be mounted, but a
substantially cylindrical shape is ordinarily adopted as the outer
shape.
[0060] The parts of igniter 20 include a header 40,
electroconductive pins 51, 52, and a heat generating body 30 placed
on one surface of the header 40.
[0061] The heat generating body 30 is enclosed by a cup 12 and a
priming 14 (for example, zirconium/potassium perchlorate) is
charged in the cup 12. The cup 12 is surrounded by a resin 16 and
the resin 16 is formed integrally with a metal collar 18.
[0062] When the igniter assembly 10 is assembled in a gas generator
for an air bag, the electroconductive pins 51 and 52 are connected
to a power source (an automobile battery) via a connector connected
with lead wires.
[0063] The igniter assembly 10 shown in FIG. 1 is assembled in a
gas generator for an air bag and ignites and burns a gas generating
agent or a transfer charge arranged as needed, so that it
contributes inflation and development of an air bag. Manufacturing
(assembling) of the parts of igniter 20 used in such an igniter
assembly 10 can be performed according to steps such as shown in
FIG. 2(a) to FIG. 2(c).
[0064] As shown in FIG. 2(a), first, the electroconductive pins 51
and 52 are pushed into two through-holes 45 and 46 provided in the
header 40. At this time, the electroconductive pins 51 and 52 may
be pushed in the through-holes from one surface 41 to the other
surface 42, or they may be pushed in the direction reversed
thereto. Even when the electroconductive pins 51 and 52 are pushed
in from either direction, one end 51a of the electroconductive pin
51 and one end 52a of the electroconductive pin 52 project slightly
from the header one surface 41.
[0065] The header 40 shown in FIG. 2(a) comprises a material having
a insulating property such as a glass, and shapes and sizes of
inner diameters of the through-holes 45 and 46 and shapes and outer
diameters of the electroconductive pins 51 and 52 are adjusted such
that the electroconductive pins 51 and 52 are press-fitted into the
through-holes 45 and 46.
[0066] The heat generating body 30 illustrated in FIG. 2(a) is
shown with a plan view, and it has a heat generating portion 31,
two holes 32 and 33 for allowing penetration of the
electroconductive pins, and electroconductive contacting portions
34 and 35 coming in contact with the electroconductive pins 51 and
52. The heat generating body 30 may comprise the heat generating
portion 31 and the contacting portions 34 and 35 formed on a
printed substrate by etching.
[0067] The electroconductive pins 51 and 52 shown in FIG. 2(a) is
made of a deformable metal such as aluminum, stainless steel or the
like, and they have a rod like shape as illustrated.
[0068] Next, as shown in FIG. 2(b), the one end portion 51a of the
electroconductive pin 51 and the one end portion 52a of the
electroconductive pin 52, and the heat generating body 3, which are
projected from the header one surface 41, are allowed to penetrate
two holes 32 and 33 of the heat generating body 30 respectively,
and the heat generating body 30 is put on the header one surface
41. Shapes and sizes of the two holes 32 and 33 of the heat
generating body 30 cannot be limited as long as the
electroconductive pins 51 and 52 penetrate into the holes, and they
may be equal to or slightly larger than outer diameters of the
electroconductive pins 51 and 52.
[0069] In this connection, a state illustrated in FIG. 2(b) may be
obtained by putting the heat generating body 30 on the header one
surface 41 and then, simultaneously making the two holes 32 and 33
of the heat generating body 30 and the two through-holes 45 and 46
provided in the header 40 penetrated with the electroconducitve
pins 51 and 52.
[0070] Next, as shown in FIG. 2(c), using a proper pushable tool,
the heat generating body 30 is fixed in such a way that the one end
portion 51a of the electroconductive pin 51 and the one end portion
52a of the electroconductive pin 52 are deformed in a crushing
manner (or crimped or riveted) and sandwiching the heat generating
body between the deformed portions 51a and 52a and the header one
surface 41. Assembling of the parts of igniter 20 is completed by
this fixing work.
[0071] Since the heat generating body 30 can be held by only
crashing to deform the one end portions of the electroconductive
pins 51 and 52, a complicated welding work or soldering work is
made unnecessary, so that a manufacturing cost is also reduced.
[0072] A deformed state of the deformed portion is satisfactory as
long as the heat generating body 30 can be fixed, and also, such a
shape maybe adopted that a surface of the deformed portion opposite
to the header one surface 41 is flat but a surface not opposite to
the header one surface is non-flat (for example, a semi-spherical
surface as shown in the drawing). By adopting such a shape, since
the heat generating body 30 is sandwiched and held between the
deformed portions 51a and 52a in a flat shape and the header one
surface 41, a fixing strength is enhanced and also, electric
connections between the electroconductive pins 51 and 52 and the
electroconductive contacting portions 34 and 35 are surely
realized.
[0073] Since the gas generator for an air bag is required to
operate reliably for 10 years or more which corresponds to the life
of a vehicle, it is required in the igniter assembly 10 that, in
particular, the heat generating body 30 and the electroconductive
pins 51 and 52 are held in an electrically normal contacting
state.
[0074] In the parts of igniter 20 illustrated in FIG. 2(c), since
the heat generating body 30 is sandwiched and fixed between the one
end portions 51a and 52a of the electroconductive pins 51 and 52
and the header one surface 41, connection failure hardly occurs due
to repetitive stress caused by vibrations or the like during
vehicle driving, as compared with a case in which connection is
made by welding, soldering or the like.
[0075] Further, by adjusting the shapes and the outer diameters of
the electroconductive pins 51 and 52 and the shapes and inner
diameters of the through-holes 45 and 46 of the header to allow
press-fitting of the electroconductive pins 51 and 52, that is, by
making the press-fitted electroconductive pins 51 and 52 immovable
even with repetitive stress caused by vibrations or the like during
vehicle driving, a fixing strength for the heat generating body 30
can be elevated.
[0076] In the igniter assembly 10 assembled with the parts of
igniter 20, an electric current flows, for example, from the
electroconductive pin 51 to reach the heat generating body 30 and
flows in the electroconductive pin 52 via the contacting portion
34, the heat generating portion 31 and the contacting portion 35.
In this course, the heat generating portion 31 of the heat
generating body 30 generates heat to ignite and burn the priming.
In the parts of igniter 10 of the first embodiment, since a
connection strength between the electroconductive pins 51, 52 and
the heat generating body 30 is high, an activation reliability of
the igniter assembly 10 is enhanced, and a reliability of the gas
generator for an air bag is also enhanced.
[0077] (2) Embodiment 2
[0078] A second embodiment of the present invention will be
explained with reference to FIG. 3(a) to FIG. 3(c). FIG. 3(a) to
FIG. 3(c) are step diagrams of a manufacturing method (an
assembling method) of parts of igniter 20. In this case, FIG. 3(a),
two heat generating bodies are shown in a plan view and a side view
respectively, but only a single heat generating body 30 is
used.
[0079] As illustrated in FIG. 3(a), the heat generating body 30 is
put on a header one surface 41. At this time, the heat generating
body 30 is placed such that the positions of two through-holes 45
and 46 provided with a header 40 and the positions of two holes 32
and 33 provided with the heat generating body 30 are coincident
with each other.
[0080] The heat generating body 30 includes a heat generating
portion (a heat generating resistance element) 31 and
electroconductive contacting portions 34 and 35 formed on a printed
substrate 36 comprising a flexible material such as a plastic
material, and holes 32 and 33 for allowing penetration of an
electroconductive pin are respectively provided in the contacting
portions 34 and 35.
[0081] In this connection, since the heat generating portion 31 has
a very narrow width, it is preferable that the heat generating
portion is formed by etching. Further, by forming the heat
generating portion 31 in an S-shape, even if the coefficients of
thermal expansion of the printed substrate 36 and the heat
generating portion 31 are different from each other, a deformation
due to a difference in coefficient of thermal expansion can be
absorbed by the shape (the S-shape), so that disconnection of the
heat generating portion 31 becomes difficult to occur, which is
desirable.
[0082] The header 40 shown in FIG. 3(a) comprises a material having
an insulating property such as a glass, and the shapes and sizes of
the inner diameters of the through-holes 45 and 46 and the shapes
and sizes of the outer diameters of the electroconductive pins 51
and 52 are adjusted such that the electroconductive pins 51 and 52
are press-fitted into the through-holes 45 and 46.
[0083] The shapes and sizes of the two holes 32 and 33 of the heat
generating body 30 is not limited as long as the electroconductive
pins 51 and 52 can penetrate into the holes, and the holes may be
formed to have sizes equal to or slightly larger than outer
diameters of the electroconductive pins 51 and 52.
[0084] Next, as shown in FIG. 3(b), the electroconductive pins 51
and 52 are pushed from the header one surface 41 toward the other
surface 42 to penetrate the holes 32 and 33 of the heat generating
body 30 and the through-holes 45 and 46 of the header 40.
[0085] The electroconductive pins 51 and 52 are in a nail like
shape having flange portions 53 and 54 at one ends thereof, and
back surfaces 53a and 54a of the flange portions 53 and 54 are
flat.
[0086] Then, as illustrated in FIG. 3(c), the electroconductive
pins 51 and 52 are pushed in until the back surface 53a of the
flange portion 53 and the back surface 54a of the flange portion 54
abut against a surface of the heat generating body 30
(electroconductive contacting portions 34 and 35). Assembling of
the parts of igniter 20 is completed by this pushing-in work.
[0087] At this time, since the back surfaces 53a and 54a are flat,
the heat generating body 30 can be held firmly by sandwiching the
heat generating body 30 between these flat surfaces and the header
one surface 41. Then, since the heat generating body 30 can be held
by only penetrating the nail-shaped electroconductive pins 51 and
52 provided with the flange portions, not only a welding work or a
soldering work is made unnecessary but also the heat generating
body 30 can be fixed by a simple work.
[0088] Further, the electroconductive pins 51 and 52 are caused to
penetrate the holes 32 and 33 of the heat generating body 30 in
advance and, in this state, the electroconductive pins 51 and 52
are caused to penetrate the through-holes 45 and 46 from the header
one surface 41, so that assembling is conducted such as shown in
FIG. 3(c).
[0089] Furthermore, when undulations are formed on rod-shaped
portions (portions except for the flange portions 53 and 54) of the
electroconductive pins 51 and 52, falling-off or loosening of the
electroconductive pins 51 and 52, lowering of a holding force for
the heat generating body 30, or weakening of electric connections
of the flange back surfaces 53a and 54a and the electroconductive
contacting portions 34 and 35 is prevented in the state shown in
FIG. 3(c). In this connection, formation of the undulations on the
electroconductive pins 51 and 52 may be conducted before or after
the electroconductive pins are caused to penetrates the header 40,
and the undulations may be formed on the whole portions (the whole
portions of the rod-shaped portions in FIG. 3(b)) or one portions
(for example, only penetrated portions in FIG. 3(c), portions
abutting against the inner peripheral faces of the through-holes 45
and 46 of the header 40, or only both of the penetrated portion and
the abutting portions) of the rod-shaped portions.
[0090] (3) Embodiment 3
[0091] A third embodiment of the present invention will be
explained with reference to FIG. 4(a) to FIG. 4(d). FIG. 4(a) to
FIG. 4(d) are step diagrams of a manufacturing method (an
assembling method) of parts of igniter 20. In this connection, FIG.
4(a) shows a heat generating body 30 with a plan view, and the heat
generating body 30 is the same as that shown in FIG. 3 except that
it has no hole.
[0092] As illustrated in FIG. 4(a), electroconductive pins 51 and
52 are pushed into two holes 45 and 46 of a header 40. At this
time, the pins are pushes in such that grooves 55 and 56 formed on
one ends of the electroconductive pins 51 and 52 become parallel
with each other and they remain on the header one surface 41.
[0093] The electroconductive pins 51 and 52 may be pushed in from
the one surface 41 to the other surface 42, or they may be pushed
from the direction reversed thereto. The relationship between the
shapes and sizes of the electroconductive pins 51 and 52 and the
shapes and sizes of the through-holes 45 and 46 is similar to that
in Embodiments 1 and 2.
[0094] The electroconductive pins 51 and 52 have grooves 55 and 56
formed at respective one ends in widthwise directions thereof. Such
a setting is performed that the widths of the grooves 55 and 56 are
equal to or less than the diameters of the electroconductive pins
51 and 52, and the lengths of the grooves 55 and 56 (lengths in
their axial directions) are larger than the thickness of the heat
generating body 30.
[0095] Next, as illustrated in FIG. 4(b), the heat generating body
30 is fitted between the groove 55 of the electroconductive pin 51
and the groove 56 of the electroconductive pin 52. As illustrated,
since an interval between the groove 55 and the groove 56 is set to
the same as the length of the heat generating body 30, the heat
generating body 30 may be inserted from formation directions of the
groove 55 and 56 (widthwise directions of the electroconductive
pins 51 and 52).
[0096] Next, as shown in FIG. 4(c), the electroconductive pins 51
and 52 are pushed in until the heat generating body 30 and the
header one surface 41 are brought in contact with each other.
[0097] By doing so, the heat generating body 30 is fixed by being
sandwiched by the grooves 55 and 56 and the header one surface 41
and also, electric connections of the electroconductive pins 51 and
52 and the electroconductive contacting portions 34 and 35 can be
obtained. Thereby, since fixation of the heat generating body 30
and the electric connections of the electroconductive pins 51 and
52 can be achieved by only pushing the electroconductive pins 51
and 52 provided with the grooves 55 and 56, not only a welding work
or a soldering work is made unnecessary but also a work is made
simple.
[0098] Next, as illustrated in FIG. 4(d), undulations 57 and 58 are
formed on penetrated portions of the electroconductive pins 51 and
52 toward the header other surface 42. Assembling of the parts of
igniter 20 is completed with a formation for the undulations 57 and
58.
[0099] The undulations 57 and 58 are for preventing the
electroconductive pins 51 and 52 from falling off to the header one
surface 41. The undulations 57 and 58 may have constitutions for
developing the above-described action, and they may comprise plural
projections arranged in a distributing manner, plural annular
undulations formed in the axial direction, screw threads formed
spirally or the like.
[0100] The undulations 57 and 58 may be formed at a stage before
the stage shown in FIG. 4(a), namely, at a stage before the
electroconductive pins 51 and 52 are caused to penetrate the header
40. In this case, in FIG. 4(c), assembling of the parts of igniter
20 is completed.
[0101] Further, when the undulations are formed on the
electroconductive pins 51 and 52, as illustrated in FIG. 4(d), they
may be formed on only the penetrated portions, they may be formed
on only the portions existing in the header 40, or they may be
formed on both the portions existing in the header 40 and the
penetrated portions (a portion lower than the groove portion 55 of
the electroconductive pin 51 and a portion lower than the groove
portion 56 of the electroconductive pin 52).
[0102] In the first embodiment shown in FIG. 2, the undulations 57
and 58 can be formed on the electroconductive pins 51 and 52 for
achieving a similar effect.
[0103] (4) Embodiment 4
[0104] A fourth embodiment of the present invention will be
explained with reference to FIG. 5(a) to FIG. 5(c). FIG. 5(a) to
FIG. 5(c) are step diagrams of a manufacturing method (an
assembling method) of parts of igniter 20. In this case, FIG. 5(a)
shows a heat generating body 30 with a plan view, and the heat
generating body 30 is the same as that shown in FIG. 3 except that
it has only a single hole.
[0105] A header 40 shown in FIG. 5(a) is made of an
electroconductive metal. A catching portion 60 for allowing fitting
of one end edge of a heat generating body 30 therein, which has a
L-shaped section in a widthwise direction and has a length equal to
the width of the heat generating body 30, is formed on header one
surface 41.
[0106] The catching portion 60 is made of an electroconductive
metal. The header 40 provided with the catching portion 60 can be
formed integrally by a press-molding or the like.
[0107] A single through-hole 46 is provided in the header 40, and
an electrically insulating portion 70 (figures are side views,
where the insulating portion can not be actually seen but it is
shown with oblique lines for easy understanding) is provided around
the through hole 46 over the whole thickness from the header one
surface 41 to the another face 42.
[0108] The positions of the catching portion 60 and the
through-hole 46 of the header 40 are adjusted considering the
length and width of the heat generating body 30 and the position of
the hole 33, as apparent from the next step.
[0109] Next, as illustrated in FIG. 5(b), one end edge of the heat
generating body 30 is fitted into an inside space 61 of the
catching portion 60, the hole 33 and the through-hole 46 are
superimposed with each other, and then, the heat generating body 30
is placed on the header one surface 41.
[0110] Thereafter, a nail-shaped electroconductive pin 51 having a
flange portion 53 is pushed from the header one surface 41 to
penetrate the hole 33 and the through-hole 46.
[0111] Next, as illustrated in FIG. 5(c), the electroconductive pin
51 is pushed in until a back surface 53a of the flange portion
comes in contact with a surface of the heat generating body 30, so
that the heat generating body 30 is fixed. Assembling of the parts
of igniter 20 is completed by this fixing work.
[0112] By doing so, one end of the heat generating body 30 is held
by the catching portion 60 and the other end thereof is sandwiched
between the back surface 53a of the flange portion and the header
one surface 41, so that the heat generating body 30 is fixed.
Thereby, since the heat generating body 30 can be fixed by only
pushing the electroconductive pin 51, not only a welding work or a
soldering work is made unnecessary but also a work is made
simple.
[0113] As illustrated in FIG. 6, such a constitution can be
employed that the catching portion 60 is formed of a metal with a
large elasticity and a slope is provided on a pressing wall 62, so
that a pressing force is applied to the heat generating body 30 in
the direction X according to pressing-in of the heat generating
body 30 in the depth direction (towards an abutting wall 63) of the
catching portion 60 and the heat generating body 30 is fastened
further tightly. By doing so, fixation of the heat generating body
30 and electric connection of the contacting portion 34 and the
header 40 is made more reliable.
[0114] In this case, an undulation may be formed on a penetrated
portion of the electroconductive pin 51 in the header other surface
side 42 like Embodiment 3 shown in FIG. 4.
[0115] Further, besides the method of using the electroconductive
pin such as shown in FIG. 2 and applying crimping and riveting to
make fixation, the fixing method of using an electroconductive pin
having such a groove as shown in FIG. 4 is also applicable.
[0116] In this embodiment, such a constitution may be adopted that
a connector, which is provided with terminals coming in contact
with any portion of the header other surface 42 and the
electroconductive pin 51 respectively, is connected so that an
electric current flowing from the electroconductive pin 51 flows
from the heat generating portion 31 and the catching portion 60 to
the header other surface 42.
[0117] (5) Embodiment 5
[0118] A fifth embodiment of the present invention will be
explained with reference to FIG. 7(a) to FIG. 7(c). FIG. 7(a) to
FIG. 7(c) are step diagrams of a manufacturing method (an
assembling method) of parts of igniter 20. In this case, in
Embodiment 5, an alloy wire (nickel-chrome wire or the like) 80 is
used as a heat generating body.
[0119] As illustrated in FIG. 7(a), electroconductive pins 51 and
52 are pushed into through-holes 45 and 46 of a header 40.
[0120] The electroconductive pins 51 and 52 have similar structures
to the electroconductive pins 51 and 52 shown in FIG. 4, and they
have grooves 55 and 56, respectively. For this reason, when the
electroconductive pins 51 and 52 are pushed in, the grooves 55 and
56 remains on a header one surface 41.
[0121] Next, as illustrated in FIG. 7(b), the alloy wire is spanned
between the grooves 55 and 56. As illustrated, the length of the
alloy wire 80 and the interval between the grooves 55 and 56 are
set to be approximately equal to each other.
[0122] It is desirable that the grooves 55 and 56 of the
electroconductive pins 51 and 52 are directed in the same direction
for spanning the alloy wire 80 therebetween, but they may be
directed in different directions. When the electroconductive pins
51 and 52 are pushed into the grooves 55 and 56 such that the
grooves are directed in the same direction, the alloy wire 80 is
arranged as shown in FIG. 8(a), but when the electroconductive pins
51 and 52 are pushed in such that the grooves 55 and 56 are
directed in reversely to each other, the alloy wire 80 is arranged
as shown in FIG. 8(b).
[0123] Next, as illustrated in FIG. 7(c), one end portion 51a of
the electroconductive pin 51 and one end portion 52a of the
electroconductive pin 52 are crimped or crushed by an appropriate
pressing tools. By this work, the alloy wire 80 is fixed by only
the one end portions 51a and 52a of the electroconductive pins 51
and 52 without coming in contact with the header one surface 41. By
this fixing work, assembling of the parts of igniter 20 is
completed.
[0124] In this case, an undulation can be formed on a penetrated
portion of the electroconductive pin 51 in the header other surface
42 side as in Embodiment 3 shown in FIG. 4. Besides, such a means
can be applied that at least peripheral portions of the
electroconductive pins 51 and 52 which abut on the through-holes 45
and 46 of the header 40 are formed in tapered shapes (wedge shapes)
so that the electroconductive pins 51 and 52 are fixed more tightly
according to pushing-in of the electroconductive pins 51 and 52
into the through-holes 45 and 46. Further, such a taper-shaped
(wedge-shaped) electroconductive pin can be applicable to
Embodiments 1 to 4.
[0125] According to Embodiment 5, not only an effect similar to the
other embodiments can be obtained but also the heat generating body
(the alloy wire) can be fixed without being influenced by the shape
or surface condition of the header 40.
* * * * *