JP2016112941A - Inflator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inflator which has light weight and structure capable of being easily manufactured, by changing a shape of a cup body.SOLUTION: An inflator is equipped with a cylinder storing compression gas, a squib, a holder, and a cup body storing a gas generating agent. Furthermore, a flange portion, a diameter-contracting portion, and a seal member are disposed from an opening end portion of the cup body. Therefore, the inflator can reduce weight and be easily manufactured. The flange portion and a fragile portion are integrally molded with the cup body.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inflator having a configuration in which a rupture plate is ruptured by a combustion gas ejected from a gas generator during operation, and pressurized gas enclosed in a pressurized gas chamber is discharged from a discharge port. The present invention relates to an inflator that can be suitably used for an airbag device that is mounted on a vehicle and inflates an airbag so as to protect passengers and pedestrians.

  2. Description of the Related Art Conventionally, airbag devices, which are occupant protection devices, have been widely used from the viewpoint of protecting occupants such as automobiles. The airbag device is equipped for the purpose of protecting the occupant from the impact generated at the time of the collision of the vehicle, etc. It is something that catches. The gas generator is a device that is incorporated in the airbag device and inflates and deploys the airbag by instantaneously generating gas when a vehicle or the like collides.

  There are various types of gas generators based on the use of installation positions and outputs with respect to vehicles and the like. One of them is a so-called cylinder type gas generator. The cylinder type gas generator has a long cylindrical shape, and is suitably incorporated in a side airbag device, a passenger side airbag device, a curtain airbag device, a knee airbag device, a seat cushion airbag device, and the like. .

  Usually, in a cylinder type gas generator, a squib is installed at one end of the housing in the axial direction, and a combustion chamber containing a gas generating agent is provided in the central portion of the housing in the axial direction to define the filter chamber. A gas outlet is provided in the peripheral wall portion of the partial housing. In the cylinder-type gas generator configured as described above, generally, the gas generated in the combustion chamber is ejected to the outside through the gas ejection port.

  Apart from the gas generator as described above, a hybrid type inflator has also been known. Conventionally, this type of inflator is arranged so as to be connected to a pressurized gas chamber in which an outlet for flowing out the enclosed pressurized gas is closed with a rupturable plate, and an outlet of the pressurized gas chamber. And a housing that holds a gas generator capable of rupturing the rupturable plate with combustion gas ejected during operation (see, for example, Patent Document 1).

However, in the case of the configuration as described above, the actuating device portion provided with the squib and the base portion provided with the gas outlet are joined to the case portion filled with the enclosed pressurized gas by a technique such as welding or caulking and fixing. As a result, the number of parts increases, and an extra process for joining the members is required.
For this reason, the increase in the number of parts does not make it possible to reduce the weight, and there is a tendency to become a large inflator. It was a thing.

JP 2010-76582 A

  In the gas generator disclosed in Patent Document 1 described above, both the case portion and the housing have a strong structure, and it has been difficult to reduce the weight of the inflator.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide an inflator having a configuration that is lightweight and can be easily manufactured.

  The inflator based on this invention is provided with the cup body which accommodates the cylinder which contains pressurized gas, a squib, a holder, and a gas generating agent. A flange portion for joining the cylinder is provided on the opening end side of the cup body, and a fragile portion is provided on the closing side end of the cup body. The holder is disposed inside the cup body, and the holder is fixed by reducing the diameter of the cup body inward in the radial direction at the reduced diameter portion of the holder.

  In the inflator based on the said invention, it is preferable that the flange part and weak part which were provided in the cup body are shape | molded integrally.

  In the inflator based on the said invention, it is preferable to arrange | position a sealing member inside a cup body.

In the inflator based on the above-mentioned present invention, it is preferable that there is a reduced diameter portion on the inner side in the axial direction of the cup body flange portion, and that a seal member is further arranged on the inner side in the axial direction.

  In the inflator based on the said invention, it is preferable that the surrounding wall part of a cup body and the inner wall part of a bottle have the substantially the same diameter, and contain the site | part arrange | positioned without gap.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the inflator of the structure which can be manufactured lightweight and easily by changing the shape of a cup body.

It is the schematic of the inflator in embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiment described below exemplifies a case where the present invention is applied to a so-called hybrid inflator that is suitably incorporated in a side airbag device or the like.

FIG. 1 is a schematic cross-sectional view showing the internal structure of an inflator according to an embodiment of the present invention. Hereinafter, the structure of the inflator in the present embodiment will be described with reference to FIG.

As shown in FIG. 1, the inflator 1 in the present embodiment is a cylinder type whose outer shape is a substantially cylindrical shape. The inflator 1 includes a gas discharge port 3 and a rupturable plate 4 on one end side of a substantially cylindrical bottle 2, and a gas generator 10 is installed on the other end side.

The bottle 2 is formed from an iron or steel metal pipe, and has a substantially cylindrical shape with one end side in the axial direction closed and the other end opened, and the peripheral wall on the one end side along the axial direction. A gas discharge port 3 is formed in the part, and a rupturable plate 4 is provided near the one end side, and the other end side is closed by a gas generator 10. The inside of the bottle 2 is filled with a compressed gas made of nitrogen gas, helium gas, argon gas, or a mixed gas thereof.
The bottle 2 has a substantially cylindrical shape, and has a compressed gas filling chamber 5 having a cylindrical shape filled with the cylindrical compressed gas, and a shaft on the one end side of the compressed gas filling chamber 5. A connecting portion 6 extending radially inward from the direction end portion, and a gas discharge chamber 7 having a cylindrical shape extending from the connecting portion 6 in the axial direction and closing the one end portion. . The compressed gas filling chamber 5 and the gas discharge chamber 7 are arranged so that the axial direction thereof is substantially parallel to the axial direction of the bottle 2 body.

  The one end side of the bottle 2 of the gas discharge chamber 7 is closed, and the other end side is opened. And in the part near the said one end part side in the bottle 2 of the said gas discharge chamber 7, the gas discharge port 3 is provided with two or more along the circumferential direction and the axial direction in the surrounding wall of the said gas discharge chamber. The plurality of gas discharge ports 3 are for communicating the space inside the bottle 2 and the outside space, and for leading the gas after passing through the gas discharge chamber 7 to the outside of the bottle 2. It is.

  A rupturable plate 4 is disposed inside the bottle 2 so as to partition the compressed gas filling chamber 5 and the gas discharge chamber 7 and close the opening of the gas discharge chamber 7. Has been. The rupturable plate 4 is formed from a thin metal plate. The rupturable plate 4 is a combustion gas generated by burning a gas generating agent 12 filled in a cup body 11 (to be described later) of the gas generator 10 by a flame generated by igniting a squib 13 (to be described later) of the gas generator 10. Flows into the bottle 2 and bursts when the internal pressure of the bottle 2 rises, and the expansion gas is discharged from the gas discharge port 3.

  The inflator 1 has a bottomed long cylindrical bottle 2 closed on one side in the axial direction having a peripheral wall portion 2A and a closed portion 2B, and a gas generator 10 extending along the same direction as the axial direction of the bottle 2. It is constituted by. As shown in FIG. 1, the gas generator 10 includes a peripheral wall portion 11A filled with a gas generating agent 12 that generates gas during combustion, a flange portion 25 extending from the peripheral wall portion 11A, and a bottom portion 11B. A bottomed cylindrical cup body 11, a squib 13 housed in the cup body 11 and capable of igniting the gas generating agent 12, and a holder 14 for fixing the cup body 11 and the squib 13 are provided. Has been.

The holder 14 is fixed so as to close the open end of the cup body 11. The holder 14 is made of metal such as iron or aluminum alloy, and includes a concave fixing portion 22 and a seal member 21 provided in an annular shape. The squib 13 is fixed to the holder 14 by caulking and the gas generating agent 12 is disposed inside the cup body 11. And the cup body 11 and the holder 14 are fixed, and it becomes the gas generator 10. When the cup body 11 and the holder 14 are fixed, the concave shape provided on the outer peripheral surface of the holder 14 in accordance with the fixing portion of the holder 14 in a state where the holder 14 is inserted into the opening end of the cup body 11. The diameter reducing portion 23 is formed by reducing the diameter of the peripheral wall portion 11 </ b> A of the cup member 11 corresponding to the fixing portion 22 by caulking in all directions and engaging with the concave fixing portion 22. By performing the eight-side caulking, the reduced diameter portion 23 is provided on the peripheral wall portion 11A of the cup body 11, and the reduced diameter portion 23 comes into close contact with the concave fixing portion 22, and the cup body 11 and A gap is prevented from occurring between the holder 14 and the holder 14. As a result, one end of the gas generator 10 is configured by the holder 14, and the other end in the axial direction of the gas generator is configured by the bottom 11 </ b> B of the cup body 11.
Further, an annular groove portion 28 different from the above-described recessed fixing portion 22 is provided on the outer peripheral surface of the holder 14. By disposing a seal member made of an O-ring or the like in the annular groove portion 28 on the inner side in the axial direction of the cup body 11, the seal member 21 is sandwiched, ensuring airtightness in the gas generator 10, and a gas generating agent. 12 moisture absorption is prevented.
Then, the cup body 11 is provided with the flange portion 25 from the end portion in the axial direction, the reduced diameter portion 23 from the flange portion 25 toward the one end portion in the axial direction, and the seal member 21 from the reduced diameter portion 23 toward the one end portion in the axial direction. By doing so, it is not necessary to use other extra members to ensure airtightness, so that the gas generator 10 and the inflator 1 can be reduced in size and weight. Further, heat generated when the flange portion 25 is fixed to the bottle 2 by welding or the like is also transferred to the holder 14 through the reduced diameter portion 23, thereby reducing the amount of heat reaching the seal member 21 and sealing. The deformation and alteration of the member 21 due to heat can also be prevented.

  The squib 13 is assembled to the opening end in the axial direction of the gas generator by being fixed to the holder 14 so as to face the gas generating agent 12. The squib 13 is disposed so as to face the space inside the cup body 11. More specifically, the holder 14 has a caulking portion 30 for caulking and fixing the squib 13 at the end in the axial direction facing the internal space of the cup body, and the squib 13 is inserted into the through portion 31. The squib 13 is clamped and fixed to the holder 14 by the caulking portion 30 described above being caulked with the wall portion of the holder 14 defining the penetrating portion 31 of the holder 14.

  The squib 13 includes an ignition part 40a and a pair of terminal pins 40b. A resistor (bridge wire) is attached to the inside of the ignition unit 40a so as to be connected to the pair of terminal pins 40b, and the ignition unit 40a is surrounded by or in contact with the resistor. Filled with sparks. Moreover, the ignition part 40a may be loaded with a charge transfer agent as necessary.

    Here, nichrome wire or the like is generally used as the resistor, and ZPP (zirconium / potassium perchlorate), ZWPP (zirconium / tungsten / potassium perchlorate), lead tricinate, or the like is generally used as the igniting agent. . The kind and amount of explosives accommodated in the squib cup are appropriately adjusted so as to satisfy the ignition sensitivity necessary for the igniter and to be necessary and sufficient for burning the gas generating agent 12. A necessary amount of the igniting agent is mainly contained in the squib cup in order to satisfy the ignition sensitivity required for the igniter. The squib cup is generally made of metal or plastic.

The squib 13 is electrically connected to the vehicle control device via the lead wire when the inflator 1 is mounted on the vehicle as an airbag device, and receives an operation signal from the control device. The gas generating agent 12 filled in the cup body 11 is burned by operating so as to generate a flame from the ignition unit 40a.
When a collision is detected, a predetermined amount of current flows through the resistor via the terminal pin. When a predetermined amount of current flows through the resistor, Joule heat is generated in the resistor, and the ignition powder starts to burn upon receiving this heat. The high-temperature flame generated by the combustion ruptures the squib cup containing the ignition powder and the transfer powder. The time from when a current flows through the resistor until the squib 13 is activated is 2 milliseconds or less when a nichrome wire is used as the resistor.

  Further, a seal member 33 made of an O-ring or the like is interposed between the squib 13 and the holder 14. The seal member 33 is for preventing a gap from being generated between the squib 13 and the holder 14, and thereby the space inside the inflator is hermetically sealed.

  A recessed portion 32 is provided continuously to the above-described through portion 31 at the end portion in the axial direction exposed to the outside of the holder 14. The recess 32 forms a female connector for receiving a male connector (not shown) of a harness for connecting the squib 13 and a control unit (not shown). In the recess 32, A portion of the squib 13 near the tip of the terminal pin 40b is exposed and positioned. A male connector is inserted into the recess 32 as the female connector, thereby realizing electrical continuity between the harness core wire and the terminal pin 40b.

  In addition, the assembly structure of the squib 13 with respect to the inflator and the seal structure between the inflator and the squib 13 are not limited to the above-described assembly structure and seal structure, and other assembly structures and seal structures are adopted. Of course it is good.

  The cup body 11 is a bottomed cylindrical cup body 11 having a peripheral wall portion 11A, a flange portion 25 extending from the peripheral wall portion 11A, and a bottom portion 11B extending from the peripheral wall portion 11A. The cup body 11 is made of a metal such as iron or steel and is disposed so as to face the squib 13. Furthermore, the cup body 11 has a fragile portion 24 at the bottom, which is one end, and the flange portion 25 at the other end. By having the flange part in the cup body 11, joining with the bottle 2 by welding can be performed easily. In addition, since the cup body 11 has the fragile portion, it is not necessary to newly join a rupturable plate and can be easily assembled. Further, a gas generating agent 12 is accommodated in the space inside the cup body 11. In particular, when the flange portion 25 and the fragile portion 24 are integrally molded into the cup body 11, the number of parts can be reduced. In addition, when the peripheral wall portion 11A of the cup body 11 and the inner wall portion of the bottle 2 include portions that have substantially the same diameter and are arranged without gaps, when the gas generator 10 is in operation, Since the bottle 2 has an effect of suppressing deformation in the radial direction of the cup body 11, as a result, the thickness of the peripheral wall portion 11A of the cup body 11 can be reduced, and weight reduction can be achieved. Here, the substantially same diameter means that the peripheral wall portion 11A of the cup body 11 and the bottle are from the state called “press fit” in which the peripheral wall portion 11A of the cup body 11 and the inner wall portion of the bottle 2 have the same diameter. It is particularly preferable that the inner wall portion 2 has a gap of about 0.5 mm, and within this range, the effect of suppressing the radial deformation of the cup body 11 can be expected.

  The gas generating agent 12 is formed by molding a predetermined chemical capable of generating combustion gas at the time of combustion into a predetermined shape. In the case of the embodiment, the gas generating agent 12 has a substantially spherical shape, and the cup body 11, the squib 13, The gap between is filled.

  The gas generating agent 12 is ignited by hot particles generated by burning the igniting agent ignited by the squib 13, and generates a large amount of heat and gas by burning. The gas generating agent 12 is generally formed as a molded body containing a fuel, an oxidant, and an additive. It is particularly preferable to use a fuel that contains a boron compound and that contains a nitrate as the oxidant. In addition, examples of the additive include a binder, a slag forming agent, and a combustion adjusting agent. As the binder, for example, cellulose derivatives such as hydroxypropylene methylcellulose, organic binders such as metal salts and stearates of carboxymethylcellulose, and inorganic binders such as synthetic hydroxytalcite and acidic clay can be suitably used. As the slag forming agent, silicon nitride, silica, acid clay, etc. can be suitably used. Moreover, as a combustion regulator, a metal oxide, ferrosilicon, activated carbon, graphite, etc. can be used suitably.

  The shape of the molded body of the gas generating agent 12 includes various shapes such as granules, pellets, columns, and disks. In addition, a porous (for example, a single-hole cylindrical shape or a porous cylindrical shape) having a hole inside the molded body is also used. These shapes are preferably selected as appropriate according to the specifications of the airbag device in which the hybrid inflator is incorporated. For example, the shape in which the gas generation rate changes with time during combustion of the gas generating agent 12 is selected. Is preferred. In addition to the shape of the gas generating agent 12, it is preferable to appropriately select the size and the filling amount of the molded body in consideration of the linear combustion rate, the pressure index, and the like. Moreover, as a manufacturing method of a gas generating agent, a conventionally known tableting manufacturing method, or an extrusion manufacturing method or the like may be used for a shape having a hole in the molded body.

  As the gas generating agent 12, it is particularly preferable to use a material containing boron / potassium nitrate or boron / 5-aminotetrazole / potassium nitrate. If this gas generating agent is used, it becomes a gas generating agent having a calorific value particularly suitable for a hybrid inflator.

  Next, the operation at the time of operation of the inflator 1 described above will be described. When a vehicle equipped with the airbag device incorporating the inflator 1 according to the present embodiment collides, the collision is detected by the collision detection means provided separately in the vehicle, and the squib 13 is activated based on this. . When the squib 13 is activated, the pressure in the ignition unit 40a is increased, whereby the ignition unit 40a is ruptured, and the flame flows out of the ignition unit 40a. The gas generating agent 12 accommodated in the cup body 11 is ignited and burned by a flame generated by the operation of the squib 13 to generate a large amount of heat and gas.

  Due to the large amount generated in the cup body 11 and the generation of heat and gas, the pressure in the cup body 11 rises, and the fragile portion 24 is cleaved, so that the compressed gas in the bottle 2 expands, and the pressure in the bottle 2 Rises. As the pressure in the bottle 2 rises, the rupturable plate 4 is cleaved, and a large amount of gas is discharged from the gas discharge port 3 to the outside of the inflator 1.

  By using the inflator according to the present embodiment described above, it is possible to provide an inflator having a configuration that can be manufactured lightly and easily.

  Thus, the above-described embodiment disclosed herein is illustrative in all respects and is not restrictive. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

DESCRIPTION OF SYMBOLS 1 Inflator, 2 bottle, 2A surrounding wall part, 2B obstruction | occlusion part, 3 gas discharge port, 4 bursting plate, 5 gas filling chamber, 6 connection part, 7 gas discharge chamber, 10 gas generator, 11 cup body, 11A surrounding wall part, 11B bottom part, 12 gas generating agent, 13 squib, 14 holder, 21 sealing member, 22 fixing part, 23 reduced diameter part, 24 weak part, 25 flange part, 28 annular groove part, 30 caulking part, 31 penetration part, 32 indentation part 33 Seal member 40a Ignition part 40b Terminal pin

Claims (5)

A bottomed cylindrical cup body containing a gas generating agent is included therein, and one end in the axial direction provided with the cup body and the other end provided with a gas outlet for jetting gas to the peripheral wall. An inflator comprising a long cylindrical bottle having
The bottle contains pressurized gas inside,
On the opening end side of the cup body is provided with a flange portion for joining to the bottle,
A fragile portion is provided at the closed end of the cup body,
A cylindrical holder is fixed inside the cup body, and has a reduced diameter portion provided annularly on the outer peripheral surface of the holder, and the cup body is radially inward at the reduced diameter portion of the holder. The inflator is characterized in that the holder is fixed by reducing the diameter.   2. The inflator according to claim 1, wherein the flange portion and the fragile portion are formed integrally with the cup body.   The inflator according to claim 1, wherein a seal member is disposed between the cup body and the holder.   The cup body has a reduced diameter portion closer to the closing side end than the flange portion in the axial direction of the flange portion, and further, the cup body at a portion closer to the closing side end than the reduced diameter portion in the axial direction. The inflator according to claim 3, further comprising a portion where a seal member is disposed between the holder and the holder. The inflator according to any one of claims 1 to 4, wherein the peripheral wall portion of the cup body and the inner wall portion of the bottle include portions that have substantially the same diameter and are arranged without a gap.

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