JPH01229739A - Device for regulating inner pressure of air bag - Google Patents

Abstract

PURPOSE:To control a gas quantity fed into an air bag to be always proper by forming an openable/closable gas passage which connects a gas generating device for air bag to the outside of the air bag and opening the gas passage at the time of the rise in temperature of atmosphere. CONSTITUTION:When the temperature in the casings 12, 14 of an inflator 10 is below a defined value, since the first spring 36 composed of a shape memory alloy of a valve 20 is not deformed, it is balanced with a second spring 38. Hence, as a piston 34 is in an ordinary position closing an introducing port 40, a gas passage from the introducing port 40 to a discharge port 32 through the inside of a cylinder 24 is closed. On the other hand, when the temperature in the casings 12, 14 becomes above the defined value, since the first spring 36 is deformed, a piston 34 is moved against a second spring 38 opening the introducing port 40. As a result, part of gas generated by the inflator 10 at the time of the collision of a vehicle is discharged out of the discharge port 32.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an internal pressure regulating device for an airbag, and more specifically, for maintaining gas pressure within an airbag at an appropriate level regardless of changes in ambient temperature. The present invention relates to an airbag internal pressure adjustment device configured as follows.

(Prior art) An airbag system is an airbag system that receives gas from a gas generator to inflate when a vehicle crashes, and prevents a secondary collision with a steering wheel, etc. by catching the occupant's body thrown forward. well known. In such a system, an inert gas such as nitrogen gas or a combustible gas such as explosives is used as the gas to fill the airbag. Among these, an example of using combustion gas is
The technique described in Publication No. 129 can be cited (problem to be solved by the invention).When a combustion type gas is used as the gas to fill an airbag, the characteristics of such combustion type gas vary depending on the ambient temperature. There is a disadvantage that the amount of gas generated during combustion is different. On the other hand, it is desirable for an air bang to always receive an appropriate amount of gas regardless of changes in ambient temperature to maintain a constant internal pressure and stabilize energy absorption performance. Therefore, an object of the present invention is to To provide an airbag internal pressure regulating device capable of always ensuring sufficient energy absorption performance by regulating the amount of gas supplied to the airbag according to changes in ambient temperature and keeping the hang internal pressure at an appropriate level.

(Means for Solving the Problems) In order to solve the above object, the present invention forms a gas passage connecting the device to the outside of the airbag in an airbag gas generating device so that the device can be opened and closed. The passage is configured to be opened when the ambient temperature rises above a predetermined value.

(Function) When the ambient temperature exceeds a predetermined value, the gas passage connecting the gas generator and the outside of the air bunk is opened, so if a vehicle collides and gas is generated in that state, The generated gas is partially released through the passage, and the remainder is supplied to the airbag, making it possible to maintain an appropriate amount of gas supplied into the bag and stabilizing energy absorption performance. I can do it.

(Example) Hereinafter, an example will be described with reference to attached page M. In FIG. 1, reference numeral 10 designates an inflation flake, which is the gas generating device described above, and the inflation flake includes a casing consisting of a front half 12 and a rear half 14. A flange portion 12a is formed at the open end of the casing 11 and 1 half portion 12, and a steering handle (not shown) or the like is attached to the portion 16 via the flange portion 12a. .

Further, a flange portion 14a is similarly formed at the opening end of the rear half portion 14 of the casing, and both halves of the casing have flange portions 12a and 14a with their opening sides facing each other.
are integrated by joining them airtight.

A fuze 18 is installed in the center of the casing, and two valves 20 are provided on both sides of the fuze 18.
Furthermore, gunpowder 22 is charged as a combustion type gas generating agent into the other gaps. The valve 20 has a generally cylindrical shape and includes a cylinder 24, as best shown in the second circle. The cylinder 24 is closed at one end and has a protrusion 26 projecting outward, and the other end is open and a cap 28 is fitted therein. The cap 28 is also formed with a second protrusion 30 that protrudes outward.
The protrusion is provided with a hole that communicates the camp and the inside of the cylinder with the outside to form a discharge port 32. These first and second
The projections 26.30 engage holes drilled in the casing to maintain the valve in the position shown within the casing.

Inside the cylinder of the valve 20 is a disk-shaped piston 3.
4 is slidably housed therein, and a first spring 36 and a second spring 38 are loaded with the piston in between. Further, an elliptical introduction hole 40 that communicates the inside and outside of the cylinder is bored at a suitable position near the center of the cylinder.

Note that the long diameter of this introduction hole 40 is set to a degree that does not exceed the length of the piston 34 in the axial direction. In this embodiment, the first spring 36 is made of a shape memory alloy. That is, the first spring 36 has a characteristic such that when the temperature inside the casing exceeds a predetermined value, for example 30° C., it expands as shown in FIG. 2 and presses the piston 34 toward the second spring 38. Shape memory alloy shall be used. As shown in FIG. 1, the second spring 38 holds the piston 34 near the center of the cylinder by opposing the spring force when the first spring, which is below the predetermined temperature, does not change its shape. Use a regular metal one with a certain degree of high clearance. Further, a gas supply hole 44 is bored in the side surface of the front half 12 of the casing, and an air bund 46 is attached to the outer edge of the hole 44 through a stopper 48 to airtightly fix the same end to the part 16. It is then folded and stored. Therefore,
The interior space of the casing is configured to communicate with the interior space 50 of the airbag via the gas supply hole 44.

Next, the operation of this device will be explained. When the temperature inside the casing is below a predetermined value, that is, 30°C, the valve 20
Since the first spring 36 made of a shape memory alloy does not change its shape, the spring force with the second spring 38 is balanced, and the piston 34 is also in the position shown in FIG. 1 (or as shown in the imaginary line in FIG. 2). Therefore, the gas passage from the introduction hole through the cylinder, through the discharge port 32, and to the outside of the rear half of the casing is closed. In this state, if the vehicle (not shown) equipped with this device collides with another vehicle, the resulting change in gravitational acceleration is detected via a sensor (not shown), and the control is performed. The fuse 18 in the casing is ignited through a signal line 52 via a device (not shown), and the gunpowder 22 is combusted to generate gas.

All generated gas is sent to the interior space 50 of the airbag through the gas supply hole 44.

Thus, when the temperature inside the casing increases to exceed 30° C., the first spring 36 changes its shape and expands. As a result, the deformation force is added to the original spring force to press and move the piston 34 toward the second spring 38, opening the introduction hole 40. If a collision occurs and the gunpowder explodes in this state, a portion of the generated gas will flow from the introduction hole 40 to the inside of the cylinder and the discharge port 32.
The remaining gas is discharged through the gas supply hole 44 to the outside of the casing rear half 16, and the remaining portion is supplied into the airbag through the gas supply hole 44. Therefore, the pressure within the air hang does not become excessive, and the body energy of the occupant can be appropriately absorbed. In this case, the amount of gunpowder 22 to be loaded is appropriately set based on the amount of gas generated when burned at a temperature of 30° C. or lower where no gas release path is formed. Further, the diameter of the introduction hole, the spring force, the diameter of the discharge port, etc. that define the gas discharge path shall be appropriately set based on the amount of gas to be relieved.

With such a configuration, the internal pressure of the airbag can be maintained at a predetermined value or less by releasing excess gas generated when combustion occurs at an ambient temperature higher than a predetermined value, thereby making it possible to stabilize energy absorption performance. Although a spring made of a shape memory alloy was used in the above embodiment to detect temperature changes, it is also possible to use other temperature detection means and use a spring made of a normal metal material to move the piston. Needless to say, it's a good thing.

(Effects of the Invention) The present invention forms a gas passage in an airbag gas generation device that connects the device to the outside of the airbag so that it can be opened and closed freely, and when the ambient temperature rises above a predetermined value, the passage Since it is configured to open the air hang, the amount of gas supplied to the air bag can be limited to a predetermined amount or less regardless of changes in the ambient temperature, and the internal pressure of the air hang can be maintained at an appropriate level to improve its energy absorption performance. can be stabilized.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional view showing the entire internal pressure regulating device of an air bunk incorporated in an inflation flake (gas generating device), and FIG. 2 is an explanatory cross-sectional view of a valve used in the device. 10... Inflake (gas generator), ■2.14
...Casing, 16...Installation is part, 18...
Fuse, 20... Valve, 22... Gunpowder, 24...
Cylinder, 32... Discharge port, 34... Piston, 3
6...First spring (made of shape memory alloy), 38...
-Second spring, 40...Introduction hole, 44...Gas supply hole, 46...Air bag, 48...Stopper, 5
0...Airbag interior space applicant Honda Motor Co., Ltd. agent Patent attorney Yoshi 1) Yutaka

Claims (1)

[Claims] A gas generating device for an airbag is formed with a gas passage that connects the device to the outside of the airbag so that it can be opened and closed, and the passage is opened when the ambient temperature rises above a predetermined value. Airbag internal pressure adjustment device.