JP2005067520A - Gas generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas generator capable of adjusting the gas characteristics such as the pressure, temperature or the like of gas to be generated from a second combustion chamber. <P>SOLUTION: In the gas generator comprising a combustion chamber charged with gas generating agents (14a are 14b), a bottomed cylindrical member (5) to divide the combustion chamber into two or more independent combustion chambers (4 and 7), filter means (6 and 8) which are installed in the combustion chambers (4 and 7) independently divided into two or more combustion chambers (4 and 7) and allow gas generated in the combustion chambers (4 and 7) to pass, and ignition means (16 and 17) to ignite the gas generating agents (14a and 14b), the filter means (6) is disk-shaped, and arranged on the inner side of the cylindrical member (5). The thickness of the filter means (6) is 2-25 mm, and the apparent density is 2.5-5 g/cm<SP>3</SP>. A partition member (39) is provided to demarcate a flow passage of gas generated in the combustion chamber (4) inside the cylindrical member (5) between a housing (3) and itself. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a gas generator for a situation-adaptive air bag in which a gas generating agent in a housing is combusted by a plurality of igniters so that inflation and deployment of the air bag can be controlled.

  In order to protect an occupant from an impact caused by an automobile collision, a gas generator that rapidly inflates and deploys an air bag is incorporated in an air bag module mounted in a steering wheel or an instrument panel. And the gas generator operates the igniter (squib) by the electric signal from the control unit (actuator), burns the gas generating agent by the flame from this igniter, and generates a large amount of gas rapidly. It is something to be made.

Conventional gas generators always have a configuration in which the airbag is rapidly inflated and deployed regardless of the occupant's sitting posture (regular seating, non-regular seating such as forward bending) and the vehicle speed (acceleration) at the time of collision. ing. Therefore, it is difficult to deploy the airbag according to the sitting posture of the vehicle occupant and the vehicle speed (acceleration) at the time of the collision, and there is a possibility that the original function of the airbag protecting the occupant cannot be exhibited.
Therefore, in recent years, gas generators have developed gas for an adaptive airbag that deploys the airbag according to the seating posture of the occupant and the vehicle speed (acceleration) at the time of the collision, such as slowing the initial inflation of the airbag. A vessel is being proposed and developed.

For example, Patent Document 1 discloses a situation-adaptive gas generator that has two combustion chambers each provided with an igniter and in which a gas generating agent loaded in each combustion chamber sequentially burns to generate gas. It is disclosed. In this gas generator, an annular filter means is provided at the inner peripheral portion of the outer cylinder of the housing, and a first combustion chamber formed inside the filter means, and a bottomed cylindrical shape in the first combustion chamber. The second combustion chamber defined by the cylindrical tube is formed, and the first combustion chamber and the second combustion chamber can communicate with each other by a plurality of orifices formed in the side tube portion of the bottomed cylindrical tube. It is configured as follows. The gas generating agent loaded in the first combustion chamber and the second combustion chamber is burned with a time difference, thereby providing a situation-adaptive gas generator that matches the seating posture of the occupant. Here, the filter means cools the gas generated by the combustion in each combustion chamber, gives a resistance when the gas passes through, and depressurizes, and further, the residue (slag) generated during the combustion is an airbag. It is for filtering a residue so that an airbag may not be damaged by being discharged into the air.
Further, in the gas generator described in Patent Document 2, the combustion chamber is formed into two independent combustion chambers by an inner cylindrical member concentric with the housing, and each of the combustion chambers is provided with an annular coolant means. There are disclosures. There is a disclosure that it is easy to adjust the operation output of the gas generator by changing the coolant means.
Further, in the gas generators described in Patent Documents 3 and 4, there is a disclosure that a plurality of combustion chambers are arranged in the axial direction of the housing, and an annular filter means is arranged in each combustion chamber. And the gas generator of patent document 3 describes that the gas produced from each combustion chamber passes through the filter means arranged in each combustion chamber and is discharged from the gas discharge port provided in each combustion chamber. There is. Moreover, there is a description that the gas generator described in Patent Literature 4 reduces the gas passage performance near the eccentric igniter.

Special Table 2002-50358 JP 2003-89338 A JP 11-59318 A JP 2000-296756 A

In the gas generator described in Patent Document 1, the first combustion chamber and the second combustion chamber are configured to communicate with each other, and the gas generated in both combustion chambers is mixed and passes through one filter. It will be. Therefore, even if the ignition in the two combustion chambers is executed with a predetermined time difference to deploy the airbag at an appropriate timing and speed according to various collision patterns, the gas generated in the two combustion chambers is mixed. Then, since it passes through the filter means, it is difficult to control the gas characteristics such as pressure (output to the airbag) and temperature of the gas flowing into the airbag from the gas generator independently for each combustion chamber. Yes, it is difficult to properly deploy the airbag according to each collision pattern.
Moreover, in the said patent document 2, the ignition means is not arrange | positioned in each combustion chamber, but is accommodated inside the inner cylinder member concentric with the housing which divides a combustion chamber, and also coolant means is a disk-shaped shape. No gas generator is disclosed, and there is no description on how to change the coolant means (weight, thickness, etc.).
In Patent Documents 3 and 4, the two filter members are for an annular gas generator, and there is no description about the gas generator having a disk-shaped filter member and the effect thereof.

  An object of the present invention is a gas generator that has two or more combustion chambers and is configured independently of each other, and is capable of adjusting gas characteristics such as pressure and temperature of gas generated from the second combustion chamber. It is to provide a gas generator that is lighter in weight, simplified in structure, and reduced in manufacturing cost.

Means for Solving the Problems and Effects of the Invention

A gas generator according to a first aspect of the present invention includes a cylindrical housing having a plurality of gas discharge holes in a side cylinder portion, a combustion chamber formed in the housing and loaded with a gas generating agent (14a, 14b), A bottomed cylindrical cylindrical member (5) that divides the combustion chamber into two or more independent combustion chambers (4, 7), and each combustion chamber (4, 7) that is independently partitioned into the two or more chambers. And a filter means (6, 8) through which gas generated in each combustion chamber (4, 7) passes, and is installed so as to protrude into each combustion chamber (4, 7) and is loaded into each combustion chamber. Ignition means (16, 17) for igniting the gas generating agent (14a, 14b), and the gas generated in the combustion chambers (4, 7) together with the plurality of gas discharge holes (15). A gas generator that discharges gas to an airbag by passing through the bottomed cylindrical cylindrical material (5) A hole (31) is provided in the part (30), the hole (31) is sealed, the filter means (6) is disc-shaped and is arranged inside the cylindrical member (5), and the filter means (6 ) Of the combustion chamber (7) outside the cylindrical member (5) having a thickness of 2 to 25 mm and a bulk density of 2.5 to 5 g / cm ³ in the gas passage direction. A partition member that constitutes the axial end surface of (3) and defines a gas flow path generated in the combustion chamber (4) inside the cylindrical member (5) with the housing (3) (39) is provided.

  According to the above configuration, the inside of the cylindrical material (5) having a bottomed cylindrical shape serves as the second combustion chamber (4), and the gas generated from the second combustion chamber is provided at the bottom (30). Since it is supposed to be discharged through the hole (31), a disk-shaped filter means (6) can be adopted as the filter means (6). Since this disc-shaped filter means can pass the burned gas in the disc-shaped axial direction (thickness direction), the gas passage distance is uniform compared to a cylindrical or disc-shaped filter means having a hole in the center. Thus, the cooling and filtering performance is stabilized, and the degree of freedom (diameter and arrangement) of the orifice of the orifice plate is increased. Further, since it can be manufactured more easily and cheaply than the cylindrical filter means, it is possible to easily obtain products having different bulk densities and thicknesses in the direction in which the gas passes, and as a result, operating output in the second combustion chamber. Can be manufactured easily and inexpensively. Furthermore, since the filter means (6) is arranged inside the cylindrical member (5), the entire filter means can be used without providing a space required when arranged on the outside.

In addition, since the gas discharge hole (15) is shared by the first combustion chamber (7) and the second combustion chamber (4), a gas for imparting moisture resistance is provided as compared with the case where the gas discharge hole is provided separately. Since the load of the discharge hole sealing process is reduced and the structure is simplified, the gas generator can be manufactured at a lower cost.
And the 1st combustion chamber (7) which exists in the outer side of the said cylindrical material (5) is comprised by the partition member (39) in the axial direction end surface of the housing (3), and the partition member (39) and closure shell Since the space (40) is provided between the second combustion chamber and the gas (2), the gas released from the second combustion chamber passes through the space (40) and reaches the gas discharge hole, and the first combustion chamber. Never go through. Further, even if the high temperature gas generated in the first combustion chamber reaches the hole (31) via the space (40), the hole (31) is sealed, so that gas generation in the second combustion chamber occurs. There will be no deterioration of the agent. As a result, the influence of the first combustion chamber can be minimized, and the performance of the second combustion chamber can be used as it is.

Moreover, since the partition member (39) is provided, the gas generated in each combustion chamber passes through each filter means and is discharged from the gas generator. These filter means cool the gas when the gas generated in the combustion chamber passes, give the gas a passage resistance, depressurize it, and filter the residue generated during combustion It is. The effects of the pressure reduction and cooling of the gas by the filter means include the weight (heat capacity) of the filter means, specifically the diameter, bulk density, and thickness of the filter means, in addition to conditions such as the contact area with the gas of the filter means. It depends greatly on.
Therefore, the gas generator of the first invention has at least one characteristic of the filter means provided in each of two or more independent combustion chambers, with a thickness of 2 to 25 mm and a bulk density of 2.5 to 5 g. It is configured to be changeable within the range of / cm ³ . That is, according to various conditions such as the type of vehicle in which the airbag is installed, the filter means having an appropriate weight is selected and the weight of the filter means is changed, and the gas in the independent combustion chamber provided with the filter means is provided. Can be adjusted individually. For example, by selecting a filter means having a large weight, the passage resistance when gas passes through the filter means is increased, and the pressure (output) of the gas released to the airbag is slightly reduced, so that the air at the initial stage of deployment It is possible to suppress the inflation speed of the bag and the gas pressure in the airbag, or to improve the gas cooling performance in the filter means to lower the gas temperature, so that the airbag can be deployed at an appropriate deployment speed and timing. become.

Therefore, by selecting a filter means having an appropriate thickness according to various conditions such as the type of vehicle in which the airbag is mounted, and arbitrarily changing the bulk density and thickness (weight) of the filter means. The gas characteristics such as the pressure and temperature of the gas generated in the independent combustion chamber provided with the filter means can be adjusted.
In addition, when only changing the density without changing the external dimensions of the filter means, it is not necessary to change the individual part dimensions of the gas generator to which the filter means is attached, and it is possible to use common parts, so versatility. Excellent.
Here, in order to change the bulk density of the filter means, for example, the size of the mesh of the filter means formed in a mesh shape may be changed, or the material (material density) of the filter means may be changed.

A gas generator according to a second invention is characterized in that, in the first invention, the filter means (6) has a diameter of 20 to 35 mm.
In this configuration, the diameter of the filter means (6) is substantially matched with the inner diameter of the cylindrical member (5). By adopting such a configuration, in the dual type gas generator (gas generator having two combustion chambers and two ignition means) in the driver's seat of the automobile using the cylindrical member (5), the entire filter means is arranged. It can be used effectively.

  In the gas generator of the third invention, in the first or second invention, an orifice plate (32) having a plurality of orifices (33) is provided so as to cover the hole (31), and the orifice plate ( The plurality of orifices (33) provided in 32) are sealed by a rupture member (35), and the filter means (6) is provided in contact with the orifice plate (32) by a support member. It is characterized by. By adopting such a configuration, the orifice plate (32) having a plurality of orifices (33) is provided so as to cover the hole (31). It is not necessary to use a member having high strength as a member for sealing. Further, since the orifice plate and the filter means do not provide a space, the gas generator can be made more compact.

  According to a fourth aspect of the present invention, there is provided the gas generator according to any one of the first to third aspects, wherein the cylindrical member (5) is installed eccentrically from an axis of the housing (3). By adopting such a configuration, the holding part of the ignition means can be simplified as compared with the case where it is not decentered, and the gas generator can be manufactured more compactly and inexpensively.

  A gas generator of a fifth invention is characterized in that, in the first to fourth inventions, the cylindrical material (5) has an inner diameter of 20 to 35 mm and a height of 30 to 36 mm. . With such a configuration, a compact gas generator for a driver's seat can be manufactured.

  A gas generator of a sixth invention is characterized in that, in the first to fifth inventions, the plurality of gas discharge holes (15) are a combination of a plurality of holes having different hole diameters. . With such a configuration, the pressure or temperature of the gas generated in the combustion chamber can be adjusted to adjust the deployment speed of the airbag at the initial stage of deployment, the gas pressure in the airbag, and the like.

  According to a seventh aspect of the present invention, there is provided the gas generator according to any one of the first to sixth aspects, wherein the ignition means (16, 17) is independently held on the bottom plate (21) of the initiator shell (1). It is a feature. By adopting such a configuration, a simpler structure can be obtained than when the two ignition means are integrated.

  The gas generator of an eighth invention is characterized in that, in the first to seventh inventions, the filter means (6, 8) is made of stainless steel or mild steel. By adopting such a configuration, it is possible to manufacture an inexpensive filter means having good workability, heat resistance and heat capacity.

  Embodiments of the present invention will be described with reference to the drawings. First, a first embodiment will be described with reference to FIG. The first embodiment is an example in which the present invention is applied to a gas generator for inflating and deploying a driver's seat airbag provided in a steering wheel of a driver's seat. The gas generator of this example has dimensions of a maximum outer diameter of about 70 mm and a height of about 40 mm. In the following description, the vertical and horizontal directions in FIG.

  As shown in FIG. 1, the gas generator P <b> 1 is provided in the cylindrical housing 3, a cylindrical material 5 that is installed in the housing 3 and forms the second combustion chamber 4, and the cylindrical material 5. A second filter 6, a first filter 8 provided along the inner periphery of the housing 3 and forming a first combustion chamber 7 therein, gas generating agents 14a and 14b loaded in the combustion chambers 4 and 7, It comprises ignition means 16, 17 and the like provided in the combustion chambers 4, 7, respectively. It is preferable that the first filter 8 has an annular shape and the second filter 6 has a disk shape. The cylindrical housing 3 is preferably composed of an initiator shell 1 and a closure shell 2. Here, the initiator shell 1 and the closure shell 2 are abutted and joined at the joint 10 by welding or the like. However, the initiator shell 1 and the closure shell 2 can be joined by a method other than welding, for example, a method such as pressure welding. The thickness of the initiator shell 1 and the closure shell 2 is preferably in the range of 1.5 mm to 3 mm.

  The closure shell 2 constituting the cylindrical housing 3 includes a top part 11, a side cylinder part 12 extending from the top part 11 toward the initiator shell 1, and a flange part 13 extending radially outward from the side cylinder part 12. It consists of and. The side tube portion 12 is formed with a plurality of gas discharge holes 15 through which gas generated by combustion of the gas generating agents 14a and 14b is discharged. The gas discharge hole 15 is not the gas discharge hole 15 of the first combustion chamber 7 and the gas discharge hole 15 of the second combustion chamber 4 being independent, but is used as both gas discharge holes 15. . The hole diameters of the plurality of gas discharge holes 15 may be different or the same, but it is preferable that there are a plurality of holes having different hole diameters. The pore diameter is preferably in the range of 2 mm to 3.5 mm. In the gas discharge hole 15, a rupture member 18 such as an aluminum tape is attached to the inner surface of the side tube portion 12. The rupture member 18 prevents moisture and the like from entering the housing 3 from the outside.

  The initiator shell 1 that is abutted against the closure shell 2 and joined by welding, pressure welding, or the like includes a bottom plate portion 21 and a side tube portion 22 that extends from the bottom plate portion 21 toward the closure shell 2. The bottom plate portion 21 is provided with cylindrical ignition means holding portions 23 and 24 that hold the ignition means 16 and 17. An igniter 38, which is a component part of the ignition means 16 and the ignition means 17 described later, is caulked and fixed to the ignition means holding portions 23 and 24, respectively. In addition, the ignition means here includes only an igniter that is ignited by energization from the control unit, or in addition, an enhancer agent disposed inside the gas generator for reliable ignition of the gas generating agent, The container or the like may be included.

  A first filter 8 is provided along the inner peripheral wall surfaces of the side tube portions 22 and 12 of the housing 3. The first filter 8 will be described in detail later. A convex portion 25 is formed on the lower end side of the outer peripheral side portion of the first filter 8, and this convex portion 25 is formed on the side cylinder portion 22 of the initiator shell 1. The first filter 8 is reliably positioned in the housing 3 in contact with the inner peripheral wall surface. Further, since the convex portion 25 is always in contact with the initiator shell 1, the bypass of the combustion gas from the first combustion chamber 7 can be prevented. Further, a space 26 is formed by the convex portion 25 between the inner wall of the housing 3 and the first filter 8. Thus, by forming the space 26, gas from the first combustion chamber 7 and the second combustion chamber 4 described later stays and mixes in the space 26 and is discharged from the gas discharge hole 15. .

  The bottomed cylindrical cylindrical member 5 that divides the internal space of the first filter 8 into two independent chambers is eccentric from the axis of the housing 3 and is provided eccentric to the bottom plate portion 21 of the initiator shell 1. It is installed so as to cover the ignition means 16. The cylindrical material 5 is fixed to the initiator shell 1 by an arbitrary method such as pressure welding, welding, or caulking. And the gas generating agent 14a is loaded in the inside, and the 2nd combustion chamber 4 is comprised.

A hole 31 is formed in the bottom 30 of the cylindrical member 5, and an orifice plate 32 having a plurality of orifices 33 is provided so as to cover the hole 31. The orifice plate 32 is fixed to the bottom 30 of the cylindrical member 5 by an arbitrary method such as caulking. The disk-shaped second filter 6 is disposed inside the cylindrical material 5 so as to be in contact with the orifice plate 32 by using the housing-shaped plate material 34 as a support member for the second filter 6. When the second filter 6 is disposed outside the cylindrical member 5 so as to be in contact with the orifice plate 32, the generated gas passes through the orifice portion of the orifice plate 32 and only the portion of the second filter 6 corresponding to that portion. Will be used. For this reason, when the 2nd filter 6 is arrange | positioned on the outer side of the cylindrical material 5, in order to utilize the 2nd filter 6 whole, a space is necessarily needed between the 2nd filter 6 and the cylindrical material 5. FIG. However, as a result of arranging the second filter 6 inside the cylindrical member 5, the generated gas passes through the entire second filter 6, so that the second filter 6 can be provided in contact with the orifice plate 32. As a result, since the space portion can be omitted, the gas generator can be reduced in size.
In addition, the disc-shaped filter means can pass the burned gas in the disc-shaped axial direction (thickness direction), and therefore the gas passage distance compared to the cylindrical or disc-shaped filter means having a hole in the center. Becomes uniform and cooling / filtration performance is stabilized. Since the disk-shaped filter means is provided on the entire surface of the orifice plate, the diameter and arrangement of the orifice can be freely designed as compared with the disk-shaped filter means having a cylindrical shape or a hole at the center.
In FIG. 1, the outer periphery of the casing-shaped plate material 34 that is a support member is in contact with the cylindrical material (5), and the disk-shaped second filter 6 also has the outer periphery of the inner periphery of the casing-shaped plate material 34. Is in contact with. When not using a support member, it arrange | positions so that the outer periphery of the 2nd filter 6 may touch the said cylindrical material (5) directly. By adopting such a structure, that is, a structure in which no space is provided between the inner periphery of the cylindrical member (5) and the outer periphery of the second filter 6, the cooling / filtering performance is more stable and reliable.

  The plurality of orifices 33 provided in the orifice plate 32 are sealed by a rupture member 35 such as an aluminum tape. The orifice plate 32 serves as a reinforcing member for the rupture member 35 against the pressure difference between the inside and outside of the rupture member 35 that occurs when the gas generating agent 14b in the first combustion chamber 7 is ignited first. For this reason, the rupture member 35 can be reliably sealed even if it has a lower strength than the conventional rupture member 35.

  Next, the first filter 8 and the second filter 6 will be described in detail. The first filter 8 and the second filter 6 (which correspond to filter means) cool the gas and provide a passage resistance to the gas when the gas generated by the combustion passes through the combustion chambers 7 and 4. The pressure is reduced, and the residue is filtered so that the residue generated during combustion is not released into the airbag. Here, since the temperature of the gas in the combustion chambers 7 and 4 becomes a high temperature of about 1200 to 1300 ° C., for example, at the time of combustion, the first filter 8 and the second filter 6 need strength in a high temperature state. Is done. Therefore, the 1st filter 8 and the 2nd filter 6 are comprised with a high-temperature-strength wire rod made from stainless steel or mild steel, for example. Further, the first filter 8 and the second filter 6 are manufactured, for example, by forming an assembly of knitted wire mesh, plain woven wire mesh, or crimp woven metal wire material. It is preferable to manufacture. However, it is not limited to the manufacturing method mentioned above. Furthermore, in order to improve the filtration function of the residue in the gas, in the first filter 8 and the second filter 6 of the wire mesh, for example, a sintered layer obtained by sintering a metal fiber of 10 to 100 μm in a web shape, A ceramic sheet or the like may be filled.

  By the way, the effect of gas pressure reduction and cooling by the filter 6 of the second combustion chamber 4 can be adjusted by changing at least one characteristic. This greatly depends on the weight (heat capacity) of the second filter 6 as well as the conditions such as the contact area with the gas. Therefore, for example, in the gas generator P1, the weight of the second filter 6 can be changed by selecting an appropriate weight. Here, there are various methods for changing the weight of the second filter 6. For example, there are the following methods.

(1) The thickness of the second filter 6 in the vertical direction (the direction in which gas passes) is changed. Here, the thickness of the second filter 6 is preferably about 2 to 25 mm, and considering the size and the like, it is more preferable to adjust the thickness within a range of about 3 to 10 mm. However, the thickness is limited to these ranges. It is not something.
(2) The density of the second filter 6 is changed. Here, there are various methods for changing the density of the second filter 6. For example, in the second mesh filter 6, the fineness of the mesh is changed, or the above knitted metal mesh is compressed by pressing. In the case of molding, the density can be changed by changing the compression rate during press working. Furthermore, the density can also be changed by changing the amount of the metal fiber sintered layer or ceramic sheet filled. The density of the second filter 6 is preferably 2.5 to 5 g / cm ³ and more preferably 2.5 to 4.5 g / cm ³ . Here, the density means a bulk density.
(3) The material of the second filter 6 is changed to another material having a different material density.

In particular, in the case of the above (2) or (3), it is possible to change the weight without changing the external dimensions of the second filter 6, and in this case, the gas generation to which the second filter 6 is attached is generated. There is no need to change the individual component dimensions of the container P1, and since common components can be used, the versatility is excellent. Further, the second filter 6 can be changed to an appropriate weight by appropriately combining the methods (1) to (3). For example, when the diameter of the second combustion chamber is constant, it is appropriate to change the thickness within a range of 2 to 25 mm and a bulk density of 2.5 to 5 g / cm ³ .

Then, the second filter 6 having an appropriate weight is selected and the weight of the second filter 6 is changed in accordance with various conditions such as the type of vehicle in which the airbag is mounted, and the second filter 6 is provided. In addition, the characteristics of the gas generated in the second combustion chamber 4 can be adjusted. In the second combustion chamber 4 inside the cylindrical member 5, the bulk density and height are determined so that the weight of the second filter 6 is preferably 0.8 to 2 times the weight of the gas generating agent in the combustion chamber. Is done.
In the first combustion chamber 7 outside the cylindrical member 5, the weight of the first filter 8 is preferably 1.5 to 3 times the weight of the gas generating agent in the combustion chamber. For example, by selecting the first filter 8 having a large weight, the passage resistance when the gas passes is increased to weaken the gas pressure, and the inflation rate of the airbag at the initial stage of deployment or the gas in the airbag The pressure can be suppressed, and the gas cooling performance can be enhanced to lower the gas temperature.

  The inside of the housing 3 is partitioned by a partition member 39 into a space 40 between the partition member 39 and the closure shell 2 and the first combustion chamber 7. A combustion chamber 7 is formed. The ignition means 17 provided in the first combustion chamber 7 is composed of a bottomed cylindrical cylindrical tube 37 in which a transfer agent 36 is loaded, and an igniter 38 that is ignited by energization from the control unit. It is configured. The cylindrical tube 37 is provided with an ignition hole 45 for injecting a flame that the transfer agent 36 ignites and burns toward the first combustion chamber 7. The ignition hole 45 preferably has a shape / arrangement in which a flame of a transfer agent is ejected around the axis of the housing 3. The transfer agent 36 here can be any transfer agent that can be normally used. The first combustion chamber 7 is loaded with a gas generating agent 14b.

  The material of the partition member 39 is made of, for example, a stainless steel plate or a press steel plate. The partition member 39 is formed in a corrugated plate shape so that the gas flowing out from the second combustion chamber 4 to the space 40 is discharged from the gas discharge hole 15 through the space 26 by the corrugated plate-shaped partition member 39. It has become. In FIG. 1, a gas guiding member 9 is provided so that the gas generated from the second combustion chamber flows directly into the space 26 without passing through the first filter 8. When this gas guiding member 9 is provided, the partition member 39 may not be formed in a corrugated plate shape.

  The gas generator P1 configured as described above is incorporated in an airbag module to be mounted in the steering wheel. And each ignition means 16 and 17 of gas generator P1 is connected to the vehicle side connector which illustration is omitted, respectively, and is connected to a control part. The control unit includes, for example, a collision sensor (acceleration sensor) that detects a collision of an automobile, a booster circuit that energizes each ignition means 16, 17, a backup capacitor, and a squib (igniter) drive circuit. Controlled by computer.

  The gas generator P1 connected to the control unit is connected to an ignition means that ignites first when the collision sensor detects a collision of the automobile, for example, an igniter 38 that is a component of the ignition means 17. Only the ignition means 17 is actuated (energized and ignited) by the squib driving circuit, and the gas generating agent 14b in the first combustion chamber 7 is combusted to generate high-temperature gas. The gas generated in the first combustion chamber 7 flows into the first filter 8, is cooled and filtered, and is discharged from the gas discharge hole 15 through the space 26. At this stage, since only the gas generating agent 14b in the first combustion chamber 7 is combusted, the airbag gradually starts to inflate and deploy.

Subsequently, after the combustion in the first combustion chamber 7 is started, the ignition means 16 is activated (energized and ignited) with a slight time difference by a squib driving circuit controlled by a microcomputer of the control unit. Then, the gas generating agent 14a in the second combustion chamber 4 is combusted to generate a high temperature gas.
The hot gas generated in the second combustion chamber 4 flows into the second filter 6, is cooled and filtered, and flows out from the orifice 33 into the space 40. The gas that has flowed into the space 40 passes through the recess 44 formed in the gas guiding member 9 and is discharged from the gas discharge hole 15 through the space 26. Here, the gas flowing out into the space 26 is mixed with the gas from the first combustion chamber 7 and discharged from the gas discharge hole 15. A large amount of clean gas discharged from the combustion chambers 4 and 7 flows into the airbag, and the airbag is rapidly inflated and deployed.

  The gas generating agents 14a and 14b are usually non-azide compositions, for example, composed of a fuel, an oxidant, and an additive (binder, slag former, combustion modifier). Can do.

  Examples of the fuel include nitrogen-containing compounds. Examples of the nitrogen-containing compound include one or a mixture of two or more selected from triazole derivatives, tetrazole derivatives, guanidine derivatives, azodicarbonamide derivatives, hydrazine derivatives, urea derivatives, and ammine complexes.

  Specific examples of the triazole derivative include 5-oxo-1,2,4-triazole and aminotriazole. Specific examples of the tetrazole derivatives include tetrazole, 5-aminotetrazole, aminotetrazole nitrate, nitroaminotetrazole, 5,5′-bi-1H-tetrazole, 5,5′-bi-1H-tetrazole diammonium salt, 5 , 5'-azotetrazole diguanidinium salt and the like. Specific examples of the guanidine derivative include guanidine, nitroguanidine, cyanoguanidine, triaminoguanidine nitrate, guanidine nitrate, aminoguanidine nitrate, and guanidine carbonate. Specific examples of the azodicarbonamide derivative include azodicarbonamide and the like. Specific examples of the hydrazine derivative include carbohydrazide, carbohydrazide nitrate complex, oxalic acid dihydrazide, hydrazine nitrate complex, and the like. Examples of the urea derivative include biuret. Examples of the ammine complex include a hexaammine copper complex, a hexaammine cobalt complex, a tetraammine copper complex, and a tetraammine zinc complex.

  Among these nitrogen-containing compounds, one or more selected from tetrazole derivatives and guanidine derivatives are preferable, and nitroguanidine, guanidine nitrate, cyanoguanidine, 5-aminotetrazole, aminoguanidine nitrate, and guanidine carbonate are particularly preferable.

  The mixing ratio of these nitrogen-containing compounds in the gas generating agents 14a and 14b varies depending on the number of carbon atoms, hydrogen atoms and other oxidized atoms in the molecular formula, but is usually preferably in the range of 20 to 70% by weight, 30 A range of ˜60% by weight is more preferred. Moreover, the absolute value of the compounding ratio of the nitrogen-containing compound varies depending on the kind of the oxidizing agent added to the gas generating agent. However, if the absolute value of the compounding ratio of the nitrogen-containing compound is larger than the theoretical amount of complete oxidation, the minute amount of CO in the generated gas increases. As a result, the trace NOx concentration in the generated gas increases. Therefore, the range in which the optimum balance between the two is maintained is most preferable.

  As the oxidizing agent, an oxidizing agent selected from at least one of nitrates, nitrites, and perchlorates containing a cation selected from alkali metals, alkaline earth metals, transition metals, and ammonium is preferable. Oxidizing agents other than nitrates, that is, oxidizing agents that are frequently used in the field of airbag inflators such as nitrite and perchlorate can also be used, but nitrite reduces the number of oxygen in the molecule compared to nitrate. Nitrate is preferred from the standpoint of reducing the production of fine powder mist that is easily released out of the bag. Examples of the nitrate include sodium nitrate, potassium nitrate, magnesium nitrate, strontium nitrate, phase-stabilized ammonium nitrate, basic copper nitrate, and the like, and strontium nitrate, phase-stabilized ammonium nitrate, and basic copper nitrate are more preferable.

The blending ratio of the oxidizing agent in the gas generating agents 14a and 14b varies in absolute value depending on the type and amount of the nitrogen-containing compound used, but is preferably in the range of 30 to 80% by weight, particularly in the above-mentioned CO and NO _x concentrations. A range of 40-75% by weight is preferred.

  Any binder can be used as long as it does not significantly adversely affect the combustion behavior of the gas generating agent. Examples of the binder include metal salts of carboxymethyl cellulose, methyl cellulose, hydroxyethyl cellulose, cellulose acetate, cellulose propionate, cellulose acetate butyrate, nitrocellulose, microcrystalline cellulose, guar gum, polyvinyl alcohol, polyacrylamide, starch and other polysaccharides. Examples thereof include organic binders such as derivatives and stearates, inorganic binders such as molybdenum disulfide, synthetic hydroxytalcite, acid clay, talc, bentonite, diatomaceous earth, kaolin, silica, and alumina.

  The blending ratio of the binder is preferably in the range of 0 to 10% by weight in the case of press molding, and is preferably in the range of 2 to 15% by weight in the extrusion molding. As the amount added increases, the fracture strength of the molded body increases. However, the number of carbon atoms and hydrogen atoms in the composition increases, the concentration of a trace amount of CO gas that is an incomplete combustion product of carbon atoms increases, and the quality of the generated gas decreases. Moreover, since the combustion of a gas generating agent is inhibited, use by the minimum amount is preferable. In particular, if the amount exceeds 15% by weight, the relative proportion of the oxidant needs to be increased, the relative proportion of the gas generating compound decreases, and it becomes difficult to establish a practical gas generator system.

  Moreover, a slag formation agent can be mix | blended as components other than a binder as an additive. The slag forming agent facilitates filtration with the filters (first filter 8 and second filter 6) in the gas generator due to the interaction with the metal oxide generated from the oxidant component in the gas generating agent. To be added.

  Examples of the slag forming agent include naturally occurring clay, synthetic mica, synthetic kaolinite, synthetic smectite, etc., mainly composed of aluminosilicates such as silicon nitride, silicon carbide, acid clay, silica, bentonite and kaolin. Among these, artificial clay, talc which is a kind of hydrous magnesium silicate mineral, and the like can be mentioned. Among these, acidic clay or silica is preferable, and acidic clay is particularly preferable. The blending ratio of the slag forming agent is preferably in the range of 0 to 20% by weight, particularly preferably in the range of 2 to 10% by weight. If the amount is too large, the linear combustion rate is lowered and the gas generation efficiency is lowered. If the amount is too small, the slag forming ability cannot be sufficiently exhibited.

As a preferable combination of the gas generating agents 14a and 14b, a gas generating agent containing 5-aminotetrazole, strontium nitrate, synthetic hydrotalcite, and silicon nitride, or guanidine nitrate, strontium nitrate, basic copper nitrate, and acid clay is used. Examples of the gas generating agent include.

  Moreover, you may add a combustion regulator as needed. As the combustion modifier, metal oxides such as metal oxides, ferrosilicon, activated carbon, graphite, or hexogen, octogen, 5-oxo-3-nitro-1,2,4-triazole can be used. The blending ratio of the combustion modifier is preferably in the range of 0 to 20% by weight, particularly preferably in the range of 2 to 10% by weight. If the amount is too large, the gas generation efficiency is lowered. If the amount is too small, a sufficient combustion rate cannot be obtained.

  According to the gas generator P1 described above, the combustion chambers 4 and 7 are independent from each other, and the gas generated in each combustion chamber does not flow into the other combustion chamber without being cooled and filtered. By changing the weight of the second filter 6, gas characteristics such as pressure and temperature of the gas generated in the second combustion chamber 4 can be adjusted independently.

  It is also possible to load the gas generating agents 14a and 14b having the same or different compositions into the combustion chambers 4 and 7 so that the amounts of gas generated from the combustion chambers 4 and 7 are different. Furthermore, various characteristics of the gas can be controlled by adjusting the hole diameter and the number of the orifices 33. Further, since the combustion chambers 4 and 7 are independent from each other, the operation time of the ignition means 16 and 17 provided in the combustion chambers 4 and 7 is controlled, so that the configuration of the inflation and deployment of the airbag is improved. It becomes possible to control according to.

  For example, in a high-risk collision such as a frontal collision or a frontal collision at a high speed, the ignition means 16 and 17 are simultaneously activated (energized and ignited), and a large amount of airbags generated in the combustion chambers 4 and 7 are generated. Inflate and deploy rapidly with this gas. Further, in a moderate collision, the ignition means 16 and 17 are operated (energized and ignited) with a slight time difference, and the airbag is gently inflated and deployed with a small amount of gas at the initial stage of deployment. Rapid expansion and expansion with gas. Furthermore, in the case of a collision with a low degree of danger, for example, the ignition means 16 or 17 is activated (energized ignition), and the airbag is gently inflated and deployed with a small amount of gas.

Next, a second embodiment of the present invention will be described. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.
As shown in FIG. 2, the gas generator P <b> 2 is different from the gas generator P <b> 1 in the first embodiment described above, and the first filter 8 is changed from the bottom plate portion 21 of the initiator shell 1 to the top plate portion 11 of the closure shell 2. The gas induction member is not used. For this reason, the gas flowing out of the second combustion chamber 4 first passes through the second filter 6 provided in the cylindrical member 5, then passes through the space 40 between the partition member 39 and the closure shell 2, and is partitioned. It passes through the first filter 8 through the recess 44 formed in the member 39.
In the gas generator P <b> 2, the partition member 39 is bent at its ends, and each end is in contact with the first filter 8 and the cylindrical material 5, so that combustion gas bypass can be prevented.

  Also in the gas generator P2 of the second embodiment, the pressure of the gas generated from the second combustion chamber 4 provided independently of the first combustion chamber 7 by changing the weight of the second filter 6. The temperature etc. can be adjusted.

As an example of the present invention, a deployment performance test result when the weight of the second filter 6 was changed in the gas generator P1 described above was performed. In this development performance test, two types of disc-shaped second filters 6 having a weight (mass) of 10 g (a) and 17.5 g (b) are used, the amount of gas generating agent in the first combustion chamber 7 is 35 g, The pressure and temperature in the 60 L tank were measured when gas was generated by simultaneously igniting the first combustion chamber 7 and the second combustion chamber 4 with a gas generating agent amount of 11 g in the two combustion chambers 4. FIG. 3 shows changes with time in the tank pressure when two types of second filters are used. In FIG. 3, the curve “a” shows the result when the weight of the second filter is 10 g, and the curve “b” shows the result when the weight of the second filter is 17.5 g.
The dimensions of the gas generator used were an outer diameter of 70 mm, a height of 41 mm, a cylindrical material having an inner diameter of 27 mm, a height of 36.5 mm, an eccentricity of 8.5 mm, and a filter holding member having an inner diameter of 25.4 mm. A gas generating agent having the following composition was used.
Fuel component: 43.5% guanidine nitrate,
Oxidant component: 27% strontium nitrate, 23.9% basic copper nitrate,
Other: Binder / slag forming agent The height, diameter and density of the second filter used are as shown in the following table.

  First, when 10 g of the second filter 6 was used, the maximum pressure in the tank was 231 kPa, and the maximum temperature in the tank was 302 ° C. (outside temperature 24 ° C.). On the other hand, when 17.5 g of the second filter 6 was used, the maximum pressure in the tank was 216 kPa, and the maximum temperature in the tank was also reduced to 270 ° C. (outside temperature 27 ° C.). That is, it can be seen that increasing the weight of the second filter 6 increases the pressure reduction and cooling effect of the gas generated in the second combustion chamber 4. Furthermore, as shown in FIG. 3, when the weight of the 2nd filter 6 is increased, it turns out that the rise of the pressure of the gas in the tank (namely, the inside of an airbag) in the initial stage of deployment becomes moderate.

It is sectional drawing of the gas generator which concerns on the 1st Embodiment of this invention. It is sectional drawing of the gas generator which concerns on 2nd Embodiment. It is a figure which shows the time-dependent change of the pressure in an expansion | deployment performance test.

Explanation of symbols

P1, P2 Gas generator 3 Housing 4 Second combustion chamber 5 Cylindrical material 6 Second filter 7 First combustion chamber 8 First filters 14a, 14b Gas generating agent

Claims (8)

A cylindrical housing (3) having a plurality of gas discharge holes (15) in the side cylinder (12), and a combustion chamber formed in the housing (3) and loaded with gas generating agents (14a, 14b). A bottomed cylindrical cylindrical member (5) that divides the combustion chamber into two or more independent combustion chambers (4, 7), and each combustion chamber (4, 4, independently divided into two or more chambers) 7) installed in the combustion chambers (4, 7) and the filter means (6, 8) through which the gas generated in the combustion chambers (4, 7) passes. Ignition means (16, 17) for igniting the loaded gas generating agent (14a, 14b), and the gas generated in each combustion chamber (4, 7) is the plurality of gas discharge holes (15). A gas generator that discharges gas to the airbag by passing through
A hole (31) is provided in the bottom (30) of the cylindrical member (5) having a bottomed cylindrical shape,
The hole (31) is sealed;
The filter means (6) is disc-shaped and disposed inside the cylindrical member (5);
The filter means (6) has a thickness of 2 to 25 mm and a bulk density of 2.5 to 5 g / cm ³ in the direction in which the gas passes,
The flow path of the gas produced in the combustion chamber (4) inside the cylindrical material (5) while constituting the axial end surface of the housing (3) of the combustion chamber (7) outside the cylindrical material (5) A gas generator, characterized in that a partition member (39) is provided between the housing (3) and the partition member (39).   Gas generator according to claim 1, characterized in that the filter means (6) has a diameter of 20 to 35 mm. An orifice plate (32) having a plurality of orifices (33) is provided so as to cover the hole (31),
The plurality of orifices (33) provided in the orifice plate (32) are sealed with a rupture member (35),
The gas generator according to claim 1 or 2, wherein the filter means (6) is provided by a support member so as to contact the orifice plate (32).   The gas generator according to any one of claims 1 to 3, wherein the cylindrical member (5) is installed eccentrically from an axis of the housing (3).   The gas generator according to any one of claims 1 to 4, wherein the cylindrical material (5) has an inner diameter of 20 to 35 mm and a height of 30 to 36 mm.   The gas generator according to any one of claims 1 to 5, wherein the plurality of gas discharge holes (15) are a combination of a plurality of holes having different hole diameters.   The gas generator according to any one of claims 1 to 6, wherein the ignition means (16, 17) is independently held by a bottom plate part (21) of the initiator shell (1). . The gas generator according to any one of claims 1 to 7, wherein a material of the filter means (6, 8) is stainless steel or mild steel.

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