JP2002054895A - Electric initiator and initiator assembly employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric initiator, improved in the reliability by providing stabilized electric characteristics, and an initiator assembly employing the same. SOLUTION: The electric initiator is constituted of two pieces of conductive bodies, an insulating body provided between the mutual heads of conductive bodies and an electric resistance wire, exposed from the upper end of the insulating body and bridged between the mutual heads of conductive bodies. The distance (L) of the electric insulating body between the heads of two pieces of conductive bodies is formed so as to be 0.8 times or more of a horizontal distance (I) of a part for determining the value of resistance of the electric resistance wire between the mutual conductive bodies.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inflator for filling a vehicle airbag or an inflatable article.
More particularly, it relates to an electric initiator and an initiator (electric detonator) assembly for igniting a propellant (ie, a gas generating agent) in an inflator.

[0002]

BACKGROUND OF THE INVENTION Initiators for inflating a vehicle airbag or other inflatable article include an initiator assembly for igniting a propellant (gas generating agent) contained within an inflator housing. The inflator activates a propellant (gas generating agent) by the operation of the initiator assembly, and generates gas for filling the inflatable article. The initiator assembly generally includes an external shape or member for coupling to a support structure (eg, a structure in an inner tube of an inflator).

Hitherto, an initiator assembly having a collar member such as a metal casing for connecting to an inflator housing is known. The collar member is disposed on the outer surface of the insulator surrounding the conductive pins of the electric initiator, and forms an initiator assembly in combination with the electric initiator.

[0004] The electric initiator is formed as having two conductors, and an insulator is provided between the conductors. The conductors are electrically connected by an electric resistance wire. And
When one conductor receives the ignition signal, the other conductor has a different electric potential, so that the electric resistance wire bridged between them generates heat, thereby being disposed near the resistance wire. The ignition charge is ignited and burned.

Further, when the electric initiator is operated, an electric ignition signal is applied between the two conductors, but unintentionally, in addition to the operation signal, a weak signal such as static electricity is generated. In some cases, a large amount of electricity may be applied.

[0006]

SUMMARY OF THE INVENTION The present invention provides an electric initiator having stable electric characteristics. The electric initiator has an improved reliability, and an initiator assembly using the electric initiator. Is provided.

[0007]

SUMMARY OF THE INVENTION An electric initiator according to the present invention comprises two conductors, an insulator provided between heads of the conductors, and a conductor exposed from an upper end of the insulator. And an electric resistance wire laid between the heads of the electric conductors, and the heads of the two conductors are electric initiators arranged flush with the upper end surface of the electric insulator. The distance (L) of the electrical insulator between the heads of the two conductors is the horizontal distance (l) of the portion that determines the resistance value of the electrical resistance wire between the conductors. It is characterized by being formed 0.8 times or more, preferably 0.83 times or more, more preferably 0.9 times or more.

The electric initiator according to the present invention comprises an igniter which ignites and burns by the heat generated by the electric resistance wire, and the two conductors required to ignite the igniter are connected to each other. It is also possible to use an electric initiator in which the current applied during the application time is 2 milliseconds and 1.75 A or less, preferably 1.2 A or less.

Further, the electric initiator according to the present invention has an M
An electric circuit that performs the test specified in the MIL-STD-1512 METHOD 205 of the IL standard. The charge capacity is 150 PF, the discharge resistance is 500 Ω, and a voltage of 25 kv is applied between two conductive pins five times or more. The electrical initiator may be characterized in that the resistance between the conductors is within 10%, preferably within 8% of the resistance between the conductors before applying the voltage. it can.

Hereinafter, the electric initiator of the present invention will be described in detail with reference to the drawings.

[0011]

1 and 3 are longitudinal sectional views respectively showing an embodiment of an electric initiator according to the present invention, and FIGS. 2 and 4 show electric circuits shown in FIGS. 1 and 3, respectively. FIG. 2 is a partially enlarged perspective view of the expression initiator. FIG. 5 is a circuit diagram for applying a predetermined voltage to the electric initiator. [Embodiment 1] FIG. 1 particularly shows a first conductive pin 10a.
A metal eyelet 12 having a hole 11 through which the conductive pin 10a penetrates and electrically connecting the second conductive pin 10b; and an eyelet filled in the hole 11 and connecting the first conductive pin 10a to the eyelet. An electrical initiator 1 including an insulator 13 that insulates the first conductive pin 12 from the first conductive pin 10a.
And a metal eyelet 12 electrically connected to the second conductive pin 10b are two conductors.

A first conductive pin 10a penetrates the hole 11 of the metal eyelet 12, and an insulator 13 such as glass is filled between the two. Thereby, the first conductive pin 10a and the metal eyelet 12 (and the second conductive pin 10b) are insulated. Further, as shown in FIG. 1, the end face 14 of the first conductive pin 10b and the insulator 1
It is desirable that the metal eyelet 3 and the metal eyelet 12 be formed flush.

The first conductive pin 10a and the metal eyelet 12 have a bridge wire 15 as an electric resistance wire.
Has been erected. The bridge wire 15 is used to convert electric energy (that is, an electric signal) into heat energy, which is composed of one conductive pin 10a,
When the conductive pin receives the ignition signal, it is provided in connection with another conductive component at a different electrical potential (eg, metal eyelet 12 in FIG. 1). Such a bridge wire 15 has a melting point of 1
000 ° C. or higher, for example, platinum wire (melting point: 1870
° C) or a nichrome wire (1400 ° C). In many cases, the bridge wire 15 can be electrically connected to each conductor (10a, 12) by welding.

On the side of the eyelet 12 where the bridge wire 15 is present, a cavity 17 is formed by a cup member 16 in the form of a closed cylindrical body. The ignition charge 18 is filled in contact with the wire 15. The igniter 18 ignites and burns by the heat generated by the bridge wire 15, and for example, a zirconium-potassium perchlorate-based igniter can be used. The cup member 16 forming the cavity 17 is formed separately from the cylindrical portion forming the peripheral wall and the circular portion forming the lid, and the ignition charge 18 is formed.
After being pressed into the cavity 17, both can be integrated.

FIG. 2 shows the electric initiator 1 shown in FIG.
FIG. 3 is a partially enlarged perspective view showing a connection state of a bridge wire 15 in FIG.

As shown in FIG. 2, a metal eyelet 12 is provided.
A bridge wire 15 is bridged between the first conductive pin 10a and the first conductive pin 10a disposed through the hole 11 formed in the center thereof. Each end 18 of the bridge wire 15
Are connected to the end 14 of the first conductive pin 10a and the metal eyelet 12 by welding, and the two conductors (10
The distance (L) of the electrical insulator between the heads of a, 12) is
It is formed at least 0.8 times the horizontal distance (l) of the part that determines the resistance value of the electric resistance wire (the bridge wire 15 in this embodiment) between the conductors (10a, 12). I have. The part that determines the resistance value of the electric resistance wire is, when the electric resistance wire is the bridge wire 15, the bridge wire 15 is composed of two conductors (in the present embodiment, the first conductive pin). This is the distance between 10a and the part in contact with the metal eyelet 12), and its horizontal distance is l.

The distance (L) between the electrical insulators is the distance between the electrical insulator portions between the heads of the two conductors (10a, 12), that is, the bridge wire 15 It is the distance between the surfaces to be connected.

Thus, the distance (L) of the electrical insulator
Is set to 0.8 times or more of the horizontal distance (l) of the portion that determines the resistance value of the electric resistance line, the electric characteristics of the electric initiator are stabilized, and the reliability of the electric initiator is improved. be able to. In a preferred embodiment, the distance (L) of the electrical insulator is at least 0.83 times, more preferably 0.9 times, the horizontal distance (l) of the portion that determines the resistance of the electrical resistance wire. It is formed as described above.

Thus, the distance (L) between the electrical insulators and
Horizontal distance (l) of the part that determines the resistance value of the electric resistance wire
By adjusting and, between the two conductors (10a-12), even if unintentionally electricity other than the operation signal, for example, weak electricity such as static electricity is applied, stable electricity Electrical initiator with improved characteristics and improved reliability.

That is, usually, between two conductors (10a-12)
Since the ends of the electric resistance wires such as the bridge wire 15 erected at the end are welded to the conductors (10a, 12), the electric resistance wires are not welded to the conductors. It is in a floating state at the portion (that is, 1-L). And since this electric resistance wire is formed of an extremely thin line, when electricity flows through this electric resistance wire (15), the floating portion may have one or both of the conductors (10a or 12a). ), And the resistance of the electric resistance line (15) changes.

Naturally, if the electric resistance wire (15) is provided in advance so as to be in contact with the adjacent ends of the conductor, even if unintended electricity flows, the The horizontal distance (l) of the portion that determines the resistance value of the dynamic resistance line (15) does not change. However, in order to install the electric resistance wire between the conductors (10a-12) by welding, it is necessary to consider an error in the welding location to some extent, and if this error is considered, the electric resistance wire ( It is difficult to lay 15) in contact with the adjacent ends of the conductor.

Therefore, by adjusting the distance (L) of the electrical insulator 13 and the horizontal distance (l) of the portion that determines the resistance value of the electrical resistance line (15) as in the present invention, Even when electricity other than the actuation signal is applied, an electric initiator having stable electric characteristics and improved reliability can be obtained.

The distance (L) of the electrical insulator 13
Is the same as the horizontal distance (l) of the portion that determines the resistance value of the electric resistance line 15 (that is, 1 time), as is clear from the drawing.
Is the upper limit, and no longer.

Further, in the electric initiator 1 according to the present embodiment, the electric initiator 1 required to ignite the ignition charge 18
Two conductors (in this embodiment, the first conductive pin
The current applied between 10a and the metal eyelet 12) is preferably 1.75 A or less, more preferably 1.2 A or less, for an application time of 2 milliseconds.

Further, in the electric initiator 1 of the embodiment shown in FIG. 1, the MIL standard MIL-STD-1512 METHOD 2
An electric circuit that performs the test specified in 05
After 50 PF, a discharge resistance of 500 Ω, and a voltage of 25 kv applied between the two conductive pins five times or more, the resistance between the conductors becomes smaller between the conductors before the voltage is applied. The object of the present invention can be solved even when the resistance is within 10%, preferably within 8%.

The test specified in the MIL-STD-1512 METHOD 205 of the MIL standard is a method for inspecting the safety of an electric explosive device in a situation where static electricity is applied, and the electric circuit shown in FIG. Is performed according to the following procedure. (1) Prepare 30 electrical explosive devices. (2) Test products are adjusted in advance by performing necessary environmental tests. (3) For this inspection, the environmental condition is adjusted and left for a predetermined time. (4) Discharge 25 kv to the test point from a 500 PF capacitor through a 5 kΩ resistor. Pin-
All possible modes, such as case, pin-to-pin, etc., are checked. FIG. 6 shows an electrostatic discharge test circuit specified in the MIL-STD-1512 METHOD 205. (5) Perform the test statistically according to the handbook 106.

In the present invention, in the electric circuit of FIG. 6 used for performing the test of the MIL-STD-1512 METHOD 205 of the MIL standard, the charging capacity is 150 PF,
A voltage of 25 kv is applied five times or more between two conductive pins by an electric circuit as shown in FIG. 5 with a discharge resistance of 500 Ω. The resistance between the conductors before applying the voltage should be within 10%, preferably within 8%. In FIG. 5, the charging capacitor is
Charged by a high-voltage power supply, this charged 150 PF
From the capacitor, between the conductors such as the conductive pins of the electric initiator, via a 500Ω discharge resistor,
A voltage of 25 kv is applied.

For example, by using the above-described electric initiator, the distance (L) of the electric insulator 13 is changed to the electric resistance line (15).
The resistance value between conductors after the test can be changed to 0.8 times or more the horizontal distance (l) of the part that determines the resistance value of the resistance value between the conductors before the test. 10% or less.

An example in which the electric initiator 1 shown in FIG. 1 is used will be described after the embodiment. Embodiment 2 An electric initiator 101 shown in FIG.
Is composed of two conductors including a first conductive pin 110a and a second conductive pin 110b, and an insulator disposed through the conductor. It is formed without using the metal eyelets 12.

The electric initiator 101 shown in FIG.
Header member 113 formed of an insulator such as resin
The two conductive pins 110a and 110b can be disposed so as to penetrate them. Between the heads of the two conductive pins 110a and 110b, a bridge wire similar to that of FIGS. 115 is used as an electric resistance wire.

When the header member 113 holding the two conductive pins 110a and 110b is formed using a resin, the resin material is glass fiber or other polybutylene terephthalate (PBT) containing an inorganic filler material. And a liquid crystal polymer (LCP) containing an inorganic filler such as polyphenylene sulfide (PPS) or mineral. When these resin materials are used, the polybutylene terephthalate (PBT) should be 20 to
80% by weight of glass fiber, 20 to 80% by weight of glass fiber in polyphenylene sulfide (PPS), and 2% in liquid crystal polymer (LCP).
Those containing from 0 to 80% by weight of minerals are preferred. In particular, when forming using a glass reinforced resin containing glass fiber, it is desirable that the orientation of the glass fiber is adjusted so as to be along the drawing direction of the conductive pin inserted into the header. Further, the content of the inorganic filler material in each resin material is more preferably 30 to 50% by weight.

The header member 113 includes a bridge wire 1
On the side where 15 is arranged, similarly to the electric initiator shown in FIG. 1 and FIG. 2, a cup member 116 of a covered cylindrical body is arranged to form a cavity 117, and inside the cavity 117 , The ignition charge 118 is arranged.

FIG. 4 is a perspective view of a main part showing a connection state of the bridge wire 115 in the electric initiator 101 shown in FIG.

As shown in FIG. 4, in the electric initiator 101 of this embodiment, the electric connection between the head 114a of the first conductive pin 110a and the head 114b of the second conductive pin 110b is also made. The distance (L) between the insulators is formed to be at least 0.8 times the horizontal distance (l) of the portion that determines the resistance value of the electric resistance wire (that is, the bridge wire 115) between the conductors. .

As a result, an electric initiator having stable electric characteristics can be obtained. [Embodiment 3] The electric initiator shown in the embodiment 1 has a substantially cylindrical metal collar 19 as shown in FIG.
And the resin 20 is integrally formed between the collar 19 and the electric initiator 1 by injecting the resin 20 or the like, thereby forming an initiator assembly of the present invention. However, the two can also be integrated by caulking the metal collar 19 without integrating them by injection molding.

Similarly, the electric initiator 101 shown in the second embodiment is integrally formed with the metal collar 119, as shown in FIG.
An initiator assembly as shown in FIG.
The initiator assembly shown in FIG.
The electric initiator 101 is fixed by caulking the accommodation port 9.

These initiator assemblies are housed in a housing having a gas outlet together with gas generating means and the like which are activated by the operation of the initiator assemblies to generate working gas for inflating the airbag. And a gas generator for an airbag. In this gas generator, a coolant / filter for cooling and purifying the working gas, which is formed by using a laminated wire mesh or the like, may be used as necessary.

[0038]

First, in the electric initiator shown in FIG. 1, the resistance value between conductors (10a-12) is measured.

Thereafter, using the circuit shown in FIG. 5, the charge capacity is set to 150 PF, the discharge resistance is set to 500Ω, and 25 Kv
Is applied 10 times between conductors (ie, between the first conductive pin 10a and the second conductive pin 10b).

Thereafter, the resistance value between the conductors (10a-10b) is measured again, and the rate of change of the resistance value before and after the voltage is applied is calculated.

Table 1 shows the distance (L) of the electrical insulator 13
Table 2 shows the measurement results of the electric initiator in which the horizontal distance (l) of the portion for determining the resistance value of the electric resistance wire (15) is 0.8 times or less, that is, L / l is 0.73. (L) of the electrical insulator is 0.8 times or more of the horizontal distance (l) of the portion that determines the resistance value of the electric resistance wire, that is, L / l is set to 0.1.
85 shows an electric initiator.

[0042]

[Table 1]

[0043]

[Table 2]

As is clear from this table, by setting the distance (L) of the electrical insulator to be 0.8 times or more the horizontal distance (l) of the portion that determines the resistance of the electric resistance wire. ,
The change in the resistance of the electric resistance wire (that is, the bridge wire) before and after the voltage is applied between the conductors can be kept within 10%. Further, this change in resistance value can be made within 8%.

[0045]

According to the present invention, even when a weak electricity such as static electricity, which is not intended to operate, is applied between two conductors, the electricity having stable electric characteristics can be obtained. It can be a formula initiator. As a result, an electric initiator having improved reliability and an initiator assembly using the same can be realized.

In addition, this initiator assembly is easy to connect to the inflator housing, reduces the size of the injection molded portion (resin portion) of a plastic material, and further increases the load and cost in manufacturing. It may not be accompanied.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing one embodiment of an electric initiator according to the present invention.

FIG. 2 is an enlarged view of a main part of the electric initiator shown in FIG.

FIG. 3 is a schematic longitudinal sectional view showing another embodiment of the electric initiator of the present invention.

FIG. 4 is an enlarged view of a main part of the electric initiator shown in FIG.

FIG. 5 is an electric circuit diagram according to the present invention.

FIG. 6 is an electric circuit diagram for performing a test of MIL-STD-1512 METHOD 205.

FIG. 7 is an initiator assembly formed using the electric initiator shown in FIG. 1;

8 is an initiator assembly formed by using the electric initiator shown in FIG.

[Explanation of symbols]

 1,101 Electrical initiator 10a, 110a First conductive pin 10b, 110b Second conductive pin 11 Hole 12 Metal eyelet 13 Insulator 15,115 Bridge wire 16,116 Cup member 17,117 Cavity 18,118 Ignition charge 19,119 Metal collar 113 Header Element

Claims (13)

[Claims] 1. An electric conductor provided between two conductors, an insulator provided between the heads of the conductors, and a head of the conductor exposed from an upper end of the insulator. And the head of the two conductors is an electric initiator disposed flush with the upper end surface of the electrical insulator, and between the heads of the two conductors The distance (L) between the electrical insulators is formed to be at least 0.8 times the horizontal distance (l) of the portion that determines the resistance value of the electrical resistance wire between the conductors. Characterized electric initiator. 2. The distance (L) of the electrical insulator between the heads of the two conductors is the horizontal distance (L) of a portion that determines the resistance value of the electrical resistance wire between the conductors. l) 0.8
2. The electric initiator according to claim 1, wherein the electric initiator is formed three times or more. 3. The distance (L) of the electrical insulator between the heads of the two conductors is the horizontal distance (L) of a portion that determines the resistance value of the electrical resistance wire between the conductors. l) 0.9
2. The electric initiator according to claim 1, wherein the electric initiator is formed at least twice. 4. The electric initiator includes an igniting charge that is ignited and burned by the heat generated by the electric resistance wire, and the two conductors required to ignite the igniting charge. The electric current applied between them is as follows:
The electric initiator according to any one of claims 1 to 3, wherein the electric initiator is 75A or less. 5. The electric initiator comprises an igniter which ignites and burns by the heat generated by the electric resistance wire, and wherein the two conductors are required to ignite the igniter. The electric current applied between them is as follows:
The electric initiator according to any one of claims 1 to 3, wherein the electric initiator is 2A or less. 6. The electric initiator according to the MIL standard.
MIL-STD-1512 An electric circuit for conducting the test specified in METHOD 205, with a charge capacity of 150 PF, a discharge resistance of 500 Ω, and a conductor after applying a voltage of 25 kv between two conductive pins five times or more. The electric initiator according to any one of claims 1 to 5, wherein a resistance value between the conductors is within 10% of a resistance value between the conductors before the voltage is applied. 7. The MIL-STD-1512 METHOD 20 of the MIL standard.
An electric circuit for performing the test specified in 5
0PF, a discharge resistance of 500Ω, and a voltage of 25 kv applied between two conductive pins five times or more, a resistance value between the conductors before applying the voltage is determined. The electrical initiator according to any one of claims 1 to 5, wherein the electrical initiator is within 8% of a resistance value. 8. An electric conductor provided between two conductors, an insulator provided between the heads of the conductors, and a head of the conductor exposed from an upper end of the insulator. The heads of the two conductors are electric initiators arranged flush with the upper end surface of the electrical insulator, and are the MIL-STD-1512 METHOD 205 of the MIL standard. In the electric circuit for performing the test specified in the above, the charge value is 150 PF, the discharge resistance is 500 Ω, and after applying a voltage of 25 kv between the two conductive pins five times or more, the resistance value between the conductors is An electric initiator characterized by being within 10% of a resistance value between conductors before applying the voltage. 9. The MIL-STD-1512 METHOD 20 of the MIL standard.
An electric circuit for performing the test specified in 5
The resistance value between the conductors after applying a voltage of 25 kv between the two conductive pins five times or more with 0 PF, a discharge resistance of 500Ω, and between the conductors before applying the voltage is 9. The electric initiator according to claim 8, wherein the electric resistance is within 8% of the resistance value. 10. The electric initiator includes a first conductive pin, a metal eyelet having a hole through which the conductive pin penetrates and electrically connecting the second conductive pin, and a hole in the hole. And an insulator that insulates the first conductive pin from the eyelet, wherein the two conductors electrically connect the first conductive pin and the second conductive pin. The electric initiator according to any one of claims 1 to 9, wherein the electric initiator is a metal eyelet. 11. The electric initiator includes two conductors comprising a first conductive pin and a second conductive pin,
2. An insulator which penetrates said conductor.
The electric initiator according to any one of claims 10 to 10. 12. An electric initiator according to any one of claims 1 to 11, and a metal collar member partially surrounding an outer periphery of an insulator of the electric initiator. Initiator assembly characterized. 13. An initiator assembly including an electric initiator in a housing having a gas discharge port, and a working gas for inflating an airbag activated by the operation of the initiator assembly. 2. A gas generator for an airbag containing a gas generating means for generating the air bag, wherein the initiator assembly comprises:
3. A gas generator for an airbag, which is the initiator assembly according to item 2.