JPH0948319A - Inflator for air bag device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the dispersion of the gas generating characteristic of an inflator affected by a difference in temperature conditions. SOLUTION: Two gas generation(GG) heads 6, 6' are formed on an inflator, and a temperature sensor 14 detecting the temperature of the inflator is provided in it. A delay circuit is provided to selectively judge the state that an ignition current is fed to one GG head 6' at a required delay time and the state that the ignition current is nearly concurrently fed to both GG heads 6, 6' according to the level of the detected temperature of the temperature sensor 14. The delay circuit is set to feed the ignition current to both GG heads 6, 6' nearly concurrently in the low-temperature zone and to feed the ignition current to the GG heads 6, 6' at a long delay time as the temperature becomes high.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inflator for an air bag device which inflates and deploys an air bag.

[0002]

2. Description of the Related Art An inflator of an air bag device is activated when a predetermined impact is detected when a vehicle collides, and inflates and deploys the air bag by feeding gas into the air bag. There are two types. That is, one type is a type in which a current is passed through a squib which is an electric detonator to ignite it, and an enhancer, which is a transfer agent arranged in the vicinity thereof, is ignited to efficiently burn a gas generating agent to obtain nitrogen gas. The other type is a bezel (pressure vessel) in which pressure gas is enclosed by the pressure generated by the propellant while the squib is also ignited by passing an electric current to ignite the enhancer and igniting the propellant. A rupture disc (sealing plate) is cleaved to generate a gas mainly composed of argon gas by mixing the combustion gas generated from the propellant and the pressure gas flowing out from the bezel.

The difference between the above two types of inflators is that the former produces a main gas by burning a gas generating agent, while the latter produces a pressure gas (eg argon gas and helium) sealed in a bezel. Mixed gas) is generated as the main gas.

In the latter, there are two types of propellants that use a solid agent and a liquid fuel, and the method of cleaving the rupture disc is such that the propellant cleaves with the force of the gas generated, and the propellant and the rupture disc. In some cases, a pistol-shaped piston is arranged between the two, and the rupture disc is cleaved by moving the piston with the force of gas generated by the propellant.

The squib, the enhancer, the propellant, or an assembly part in which a piston is added to the squib is generally called a gas generation head (hereinafter abbreviated as GG head). A known inflator having this GG head is, for example, WO93 / 21042.
There is also an inflator having two gas generation heads such as (PCT / US93 / 03506).

[0006]

By the way, generally, the time-dependent pressurizing characteristic of gas generated from an inflator tends to be high in a high temperature atmosphere and low in a low temperature atmosphere.

The present invention copes with the actual situation as described above, and by forming a plurality of GG heads on the inflator and controlling the ignition time of these heads in accordance with the temperature, the natural conditions such as the atmospheric temperature in the passenger compartment can be controlled. It is an object to obtain a predetermined inflator gas boosting characteristic without being affected.

[0008]

That is, the feature of the inflator of the present invention which meets the above-mentioned object is that in the inflator for an air bag device which injects gas during the operation to inflate and deploy the air bag, at least a squib and an enhancer. , And two GG heads equipped with a propellant are formed, and a temperature sensor for detecting the temperature of the inflator is internally provided.
A delay circuit for selectively determining a state in which the ignition current is passed through the G head with a required delay and a state in which the ignition current is passed through both GG heads is provided, and the delay circuit is provided so that the detected temperature is 0. When the temperature is -10 ° C or less, the low temperature region is set to flow the ignition current to both of the GG heads substantially simultaneously in the low temperature region, while the delay time is increased as the temperature rises to set the ignition current to flow to the GG head. Where it is.

[0009]

In the inflator of the present invention described above, the temperature of the inflator is detected by the temperature sensor, and the delay circuit ignites the two GG heads simultaneously in a low temperature range to obtain a predetermined inflator gas boosting characteristic. On the other hand, when the temperature sensor detects a high temperature, the delay circuit ignites the GG head with a delay time to obtain a predetermined gas boosting characteristic. That is, as a result, in the inflator of the present invention, it is possible to obtain a predetermined inflator gas boosting characteristic without being affected by natural conditions such as the atmospheric temperature in the passenger compartment.

[0010]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an inflator according to an embodiment of the present invention. This inflator has two GG heads 6 and 6'at both ends of a bezel 7, and the bezel 7 is filled with a pressure gas. are doing.

In the inflator, when a predetermined impact is detected during a vehicle collision, a determination module (not shown) incorporated in the airbag system determines the deployment of the airbag, and the ignition circuit 1 of the GG head 6 is inspected. It is designed to pass an electric current. When a current flows through the ignition circuit 1, the squib 2 in the GG head 6 is ignited, and subsequently the enhancer 3 arranged adjacently ignites to burn the propellant 4. The enhancer 3 and the propellant 4 are composed of a reticulated metal holding plate 5 and a GG head 6
It is held inside, and the GG head 1 itself is fixed to the bezel 7 by welding. The bezel 7 is filled with the pressure gas as described above, and this gas is injected from the gas injection port 9 and then sealed by welding the ball seal 8 to the gas injection port 9.

The gas having a predetermined heat generated from the propellant 4 flows in the direction of the arrow in the figure while being mixed with the pressure gas in the bezel 7, and the dome-shaped gas is provided near the nozzle 13 by its force. The rupture disc 10 is cleaved. The rupture disc 10 is welded to the bezel 7 via the casing 11 and seals the pressure gas.

On the other hand, in the second GG head 6 ', a current also flows in the ignition circuit 1', the squib 2'is ignited, the enhancer 3'is ignited, and the propellant 4'as in the case of the first GG head 6. To burn. The enhancer 3'and the propellant 4'are held in the GG head 6'by a reticulated metal holding plate 5 '. Then, the gas having a predetermined heat generated from the propellant 4 ′ of the second GG head 6 ′ is further mixed with the mixed gas flowing out from the rupture disk 10 by further heating, and passes through the filter 12. It is supplied into the airbag (not shown) from a nozzle 13 provided in the casing 11.

The propellant 4 of the first GG head 6 and the second
The propellant 4'of the GG head 6'is provided with a substantial difference in the number of moles of gas to be generated and the amount of heat, and in this embodiment, the propellant 4 of the first GG head 6 is larger in amount. I have to.

On the other hand, the temperature sensor 14 is the first GG.
It is fixed to the head 6 and its measuring unit 15 is
However, the propellant 4 in this portion may be cut out so that the temperature of the pressure gas in the bezel 7 can be measured. Generally, the propellant 4 is in the form of a wafer (in the form of lotus root).
The atmosphere temperature of the propellant and the pressure gas can be measured by matching with the brick hole (omitted). Temperature sensor 1
For example, a thermistor type temperature sensor or the like can be used as 4. The ignition circuit and the temperature sensor 14 are linked with a delay circuit (not shown) that controls the delay time.

Next, the delay circuit will be described. This delay circuit has a state in which an ignition current is passed to the second GG head with a required delay and a state in which an ignition current is passed to both GG heads 6 and 6'at almost the same time depending on the temperature detected by the temperature sensor 14. Is to selectively judge,
In this delay circuit, when the detected temperature is about 0 to 10 ° C. or less, the low temperature region is set to a low temperature region, and an ignition current is caused to flow to both of the GG heads 6 and 6 ′ substantially simultaneously in the low temperature region. GG by increasing the delay time to the head 6 '
The heads 6 and 6'are set to flow an ignition current.

That is, the main performance of this inflator is the gas pressure in the bezel, the number of moles of gas generated by the propellant, the amount of heat, and the delay time. Has been adjusted including. This delay circuit and the delay time will be described, for example, for a system that discriminates the temperature range into a low temperature range, a normal temperature range, and a high temperature range. Assuming that passengers are in the car, taking into account the performance of the air conditioner, it is generally 0 ° C in the low temperature range.
Hereinafter, it is assumed that the normal temperature range is 0 to 40 ° C. and the high temperature range is 40 ° C. or higher. When the temperature sensor 14 detects a low temperature, the delay circuits are operated at almost the same time (including the same time) for the respective squibs 2.
Ignition current is applied to 2 '. At low temperatures, it is necessary to operate the two GG heads 6 and 6'from the initial stage in order to obtain a predetermined boosting characteristic.

On the contrary, when the temperature sensor 14 detects a high temperature,
An ignition current is passed through the squib 2'of the second GG head 6'with a delay time longer than the delay time set in the room temperature range by the delay circuit. At a high temperature, in order to obtain a predetermined boosting characteristic, it is necessary to provide the two GG heads 6 and 6'with a time difference longer than the delay time in the normal temperature range.

The delay time difference cannot be generally stated because it depends on various factors, but it is generally 200 to 300 Kgf.
With an inflator having a gas pressure of / cm ² , it is 0 to 5 msec in the low temperature range, 5 to 10 msec in the normal temperature range, and 1 in the high temperature range.
It is about 0 to 15 msec.

Although the embodiment of the present invention has been described above, in the type in which the gas generating agent is loaded in place of the pressure gas of the bezel 7, the rupture disk 10 is eliminated and the gas generating agent is enclosed in the space filled with the pressure gas. Is loaded.

[0022]

As described above, the inflator for an airbag device according to the present invention has two GG heads formed in the inflator, and the temperature sensor for detecting the temperature of the inflator is internally provided. A delay circuit is provided for selectively determining whether the ignition current is passed through one of the GG heads with a required delay and the ignition current is passed through both of the GG heads at substantially the same time depending on the temperature. When the temperature of the inflator is detected by the temperature sensor, the delay circuit ignites two GG heads at the same time in a low temperature range, while when the temperature sensor detects a high temperature, the delay circuit ignites the GG head with a delay time. By doing so, it is possible to obtain a predetermined inflator gas boosting characteristic, and an inflator that is not affected by natural conditions such as the atmospheric temperature in the passenger compartment. In which a marked effect with can be obtained gas pressure rise characteristics.

[Brief description of drawings]

FIG. 1 is a sectional view showing an inflator according to an embodiment of the present invention.

[Explanation of symbols]

 1, 1'Ignition circuit 2, 2'Squib 3, 3'Enhancer 4, 4'Propellant 5, 5 'Holding plate 6, 6'Gas generation head (GG head) 7 Bezel 8 Ball seal 9 Gas inlet 10 Rapture Disk 11 Casing 12 Filter 13 Nozzle 14 Temperature sensor

Claims (1)

[Claims] 1. An inflator for an airbag device, which injects gas during operation to inflate and deploy the airbag,
Two gas generation heads equipped with at least a squib, an enhancer, and a propellant are formed, and a temperature sensor for detecting the temperature of the inflator is provided internally. Depending on the temperature detected by this temperature sensor, one gas generation head With the delay required for the ignition current to flow,
A delay circuit is attached to both gas generation heads to selectively judge whether or not the ignition current flows at almost the same time.
Further, the delay circuit is set to a low temperature range when the detected temperature is 0 to 10 ° C. or less, and an ignition current is supplied to both of the gas generation heads substantially simultaneously in the low temperature range,
An inflator for an airbag device, wherein an ignition current is set to flow through the gas generation head with a longer delay time as the temperature rises.