JP7354033B2 - gas generator - Google Patents

Description

The present disclosure relates to a gas generator that generates combustion gas by burning a gas generating agent using an ignition device.

2. Description of the Related Art Gas generators are known that generate combustion gas by burning a gas generating agent and supply this combustion gas as a power source for realizing a desired operation. The gas generator discharges combustion gas generated by burning a gas generating agent within the outer shell to the outside from a gas outlet formed in the outer shell. Before the gas generator is operated, the gas outlet is closed with a closing member such as a seal tape. Patent Document 1 describes a gas generator in which a plurality of gas outlets are provided in the peripheral wall of an upper shell, and the gas outlets are closed with a seal tape. Patent Document 2 describes a gas generator for an air bag in which a plurality of gas exhaust ports having different diameters are formed in the peripheral wall of a diffuser shell, and the gas exhaust ports are closed with a seal tape.

JP2017-185907A Japanese Patent Application Publication No. 2003-191816

When forming a plurality of gas discharge ports in the outer shell container of a gas generator, processing tolerances may occur for each gas discharge port. In addition, there may be intensity unevenness at the blockage portion that blocks the gas discharge port. In these cases, there will be a difference in the bursting pressure of the blockage between the multiple gas exhaust ports, and when the gas generator is operating, only the blockage with a relatively low bursting pressure will rupture, and the bursting pressure will be relatively low. There is a risk that a large blockage may remain unopened. If the gas generator fails to open at some of the gas discharge ports during operation, the combustion gas will be discharged unevenly in the circumferential direction of the outer shell container. It is undesirable for the gas generator to discharge combustion gas unevenly in the circumferential direction of the outer shell container, not only for the gas generator itself but also for the device used in combination with the gas generator.

In view of the above-mentioned problems, the present disclosure aims to provide a technique that can prevent combustion gas from being discharged unevenly in the circumferential direction of an outer shell container of a gas generator.

In order to solve the above problems, the gas generator of the present disclosure has a plurality of gas discharge ports formed such that the length along the circumferential direction of the outer shell container is longer than the length along the direction perpendicular to the circumferential direction. Established.

Specifically, the gas generator of the present disclosure includes a cylindrical peripheral wall portion, a top surface portion disposed at one end of the peripheral wall portion, and a bottom surface portion disposed at the other end of the peripheral wall portion. a shell container, an igniter disposed in the outer shell container, a gas generating agent disposed in the outer shell container so as to be combustible by actuation of the igniter, and a gas generating agent formed in the outer shell container, each comprising: , a plurality of gas exhaust ports formed such that a length along a circumferential direction of the outer shell container is longer than a length along a direction perpendicular to the circumferential direction; and a closing part that closes the plurality of gas exhaust ports. , is provided.

In the gas generator of the present disclosure, a plurality of the above gas exhaust ports are formed. As a result, the gas generator is able to discharge combustion gas evenly in the circumferential direction of the outer shell container, compared to a case where a vertical hole-shaped or circular gas discharge port is formed in the peripheral wall of the outer shell container. The number of gas discharge ports formed can be reduced. When the number of gas exhaust ports to be formed is small, the number of man-hours required for forming the gas exhaust ports can be reduced, so that the processing tolerance between the plurality of gas exhaust ports can be reduced. In addition, when the number of gas discharge ports formed is small, the number of members used for the blockage part (blocking member) that closes the gas discharge ports can be reduced, which reduces the possibility of occurrence of strength unevenness in the blockage part. be able to. For this reason, the gas generator prevents differences in the bursting pressure of the blockage between multiple gas exhaust ports, and there is a possibility that the blockage at some gas discharge ports will not burst during operation. Since the combustion gas can be evenly discharged in the circumferential direction of the outer shell container. Furthermore, since the gas generator can reduce the number of man-hours required when forming the gas outlet, the manufacturing process can be simplified.

Note that one gas outlet may be closed by one closing member. In this configuration, the closing portion that closes the plurality of gas exhaust ports may be constituted by a plurality of closing members. Further, a plurality of gas exhaust ports may be closed by one closing member. In this configuration, the closing portion that closes the plurality of gas exhaust ports may be constituted by one closing member.

In the above gas generator, the ratio of the length along the circumferential direction of each of the plurality of gas discharge ports to the length along the direction orthogonal to the circumferential direction is greater than 1 and less than 2.4. It can be small. In the present disclosure, the range of ratio values was determined by finding the relationship between the value of this ratio and the bursting pressure of the occlusion. That is, when the value of this ratio is smaller than 2.4, the bursting pressure of the closed portion can be kept within a predetermined range. By forming gas exhaust ports with this ratio, it is possible to stabilize the bursting pressure of the blockages at multiple gas exhaust ports, and prevent the phenomenon that the blockages at some gas exhaust ports do not rupture during operation. It can be further reduced.

In the above gas generator, the plurality of gas discharge ports are formed in line in the circumferential direction of the peripheral wall, and the circumferential direction of the outer shell container is the circumferential direction of the peripheral wall, and the circumferential direction of the outer shell container is the circumferential direction of the peripheral wall. The direction perpendicular to may be a direction along the central axis of the peripheral wall portion. In this way, the plurality of gas exhaust ports may be formed in the peripheral wall of the outer shell container.

In the above gas generator, the plurality of gas outlets include a first gas outlet having a first opening area and a second gas outlet having a second opening area smaller than the first opening area. The first gas outlet and the second gas outlet may be arranged alternately in the circumferential direction. Here, the magnitude relationship between the first opening area and the second opening area is a magnitude relationship obtained by comparing the opening area per gas discharge port. According to this configuration, the gas generator can make the bursting pressure of the blockage part different between the first gas exhaust port and the second gas exhaust port, and can discharge combustion gas in multiple stages from each gas exhaust port. can.

In the above gas generator, the plurality of gas discharge ports are arranged in the peripheral wall portion at positions having different heights in the direction along the central axis along the circumferential direction of the peripheral wall portion. The plurality of gas discharge port rows may be formed in a direction along the central axis of the peripheral wall portion. The plurality of gas exhaust port rows may be formed in two rows, or may be formed in three or more rows.

In the above gas generator, each of the plurality of gas outlet rows includes a first gas outlet having a first opening area, and a second gas outlet having a second opening area smaller than the first opening area. the first gas outlet in one of the gas outlet rows, and the first gas outlet in one of the gas outlet rows adjacent above or below to the first gas outlet row; The second gas exhaust ports are arranged in parallel in the direction along the central axis, and the second gas exhaust ports in one gas exhaust port row and the second gas exhaust ports in the adjacent gas exhaust port row 1
The gas exhaust ports may be arranged in a line along the central axis. Here, the vertical direction of the gas generator may be along the central axis of the outer shell container. A gas generator with such a configuration can equalize the total opening area of the gas discharge ports arranged in the direction along the central axis, so that the combustion gas can be discharged evenly in the circumferential direction of the outer shell container. I can do it.

In the above gas generator, one of the gas exhaust port rows and each of the gas exhaust port rows adjacent to the one gas exhaust port row above or below are mutually arranged with the central axis in between. At least two gas exhaust ports arranged to face each other are formed, and a first imaginary line connecting the centers of the at least two gas exhaust ports arranged in one gas exhaust port row; The second imaginary lines connecting the centers of the at least two gas exhaust ports arranged in the adjacent gas exhaust port rows may pass through the central axis and be orthogonal to each other. Note that it is sufficient that at least a gas exhaust port satisfying such a positional relationship is provided, and further gas exhaust ports may be formed in the gas exhaust port row.

Further, in the above gas generator, the plurality of gas discharge ports are formed in line in a circumferential direction of the top surface portion, and the circumferential direction of the outer shell container is a direction along the circumferential direction of the top surface portion. The direction perpendicular to the circumferential direction may be a direction along the radial direction of the top surface portion. In this way, the plurality of gas exhaust ports may be formed on the top surface of the outer shell container.

In the above gas generator, each of the plurality of gas exhaust ports may be formed in an oval shape, an elliptical shape, a rectangular shape, or a diamond shape.

According to the technology of the present disclosure, it is possible to suppress combustion gas from being discharged unevenly in the circumferential direction of the outer shell container of the gas generator.

FIG. 1 is a diagram showing a schematic configuration of a gas generator according to a first embodiment. FIG. 2 is a diagram of the gas generator according to Embodiment 1 viewed from the peripheral wall side of the housing. FIG. 3 is a diagram showing a gas outlet of the gas generator according to the second embodiment. FIG. 4 is a table showing the bursting pressure of the seal tape calculated when the total length, hole diameter, and straight length of the gas discharge port are changed. FIG. 5 is a graph of the burst pressure shown in the table of FIG. FIG. 6 is a table showing the bursting pressure of the seal tape calculated when the total length and straight length of the gas discharge port are changed. FIG. 7 is a graph of the burst pressure shown in the table of FIG. FIG. 8 is a diagram of the gas generator according to Embodiment 3 viewed from the peripheral wall side of the housing. FIG. 9 is a diagram of the gas generator according to Embodiment 4 viewed from the peripheral wall side of the housing. FIG. 10 is a diagram of a gas generator according to Modification 1 of Embodiment 4, viewed from the peripheral wall side of the housing. FIG. 11 is a diagram of a gas generator according to Modification 2 of Embodiment 4, viewed from the peripheral wall side of the housing. FIG. 12 is a diagram of a gas generator according to a third modification of the fourth embodiment, viewed from the peripheral wall side of the housing. FIG. 13 is a diagram of the gas generator according to Embodiment 5 viewed from the peripheral wall side of the housing. FIG. 14 is a diagram showing the arrangement position of the gas exhaust port 5 of the gas generator according to the fifth embodiment. FIG. 15 is a view of the gas generator according to Embodiment 6, viewed from the top side of the housing.

A gas generator according to an embodiment of the present disclosure will be described below with reference to the drawings. Note that the configurations and combinations thereof in each embodiment are merely examples, and additions, omissions, substitutions, and other changes to the configurations can be made as appropriate without departing from the spirit of the present invention. This disclosure is not limited by the embodiments, but only by the claims.

<Embodiment 1>
FIG. 1 is an axial cross-sectional view of a gas generator 1 according to a first embodiment. The gas generator 1 includes a housing 4 (an example of an "outer shell container" in the present disclosure), and combusts a gas generating agent filled in the housing 4 to release combustion gas. The gas generator 1 according to the present embodiment is a so-called dual-type gas generator in which two combustion chambers are arranged above and below, and an ignition device and a gas generating agent are arranged corresponding to each combustion chamber, as described later. It is. In addition, in this specification, the operation of the igniter may be expressed as "the gas generator is activated" for convenience.

The housing 4 has an upper shell 2 and a lower shell 3 made of metal. The upper shell 2 and the lower shell 3 have a substantially cylindrical shape with a bottom, and are joined with their open ends facing each other. Thereby, the housing 4 is formed into a short cylindrical shape with both axial ends closed. Here, the direction along the central axis of the housing 4 (the central axis CA indicated by the dashed line in FIG. 1) is defined as the vertical direction of the gas generator 1, and the upper shell 2 side (the upper side in the paper of FIG. 1) is the upper side of the gas generator 1, and the lower shell 3 side (lower side in the paper of FIG. 1) is the lower side of the gas generator 1.

The upper shell 2 has a peripheral wall portion 2c and a top surface portion 2d. The top surface portion 2d has a generally circular shape when viewed from above. The peripheral wall portion 2c forms an annular wall surface surrounding the top surface portion 2d and extending generally vertically downward from the top surface portion 2d. A top surface portion 2d is connected to one end of the peripheral wall 2c, and an opening of the upper shell 2 is formed at the other end of the peripheral wall 2c. The upper shell 2 forms a concave internal space by a peripheral wall portion 2c and a top surface portion 2d. A first combustion chamber 21 is formed in the internal space of the upper shell 2 and is filled with a first gas generating agent 22 . Further, on the other end side of the peripheral wall portion 2c, a fitting wall portion 2a and an abutting portion 2b are formed in order from the opening of the upper shell 2 toward the top surface portion 2d. The fitting wall portion 2a is connected to the peripheral wall portion 2c via the abutting portion 2b. The inner diameter of the fitting wall portion 2a is larger than the inner diameter of the peripheral wall portion 2c.

The lower shell 3 has a peripheral wall portion 3a and a bottom surface portion 3b. The bottom surface portion 3b has a generally circular shape when viewed from above, similarly to the top surface portion 2d. The peripheral wall portion 3a forms an annular wall surface surrounding the bottom surface portion 3b and extending generally vertically upward from the bottom surface portion 3b. A bottom portion 3b is connected to one end of the peripheral wall 3a, and an opening of the lower shell 3 is formed at the other end of the peripheral wall 3a. The lower shell 3 forms a concave internal space by a peripheral wall portion 3a and a bottom surface portion 3b. A second combustion chamber 25 is formed in the internal space of the lower shell 3 and is filled with a second gas generating agent 26 . Note that the inner diameter of the peripheral wall portion 3a of the lower shell 3 is formed to be approximately the same as the inner diameter of the peripheral wall portion 2c of the upper shell 2. The housing 4 includes a cylindrical peripheral wall portion formed by a peripheral wall portion 2c and a peripheral wall portion 3a, a top surface portion 2d disposed at one end of the peripheral wall portion, and a bottom surface portion 3b disposed at the other end of the peripheral wall portion. , has.

The gas generator 1 includes a first igniter 23 and a second igniter 27 arranged in the housing 4 (the first igniter 23 and the second igniter 27 are an example of an "igniter" as referred to in the present disclosure). ). Holes (not shown) in which the first igniter 23 and the second igniter 27 are respectively fixed are formed in the bottom part 3b of the lower shell 3, and the first igniter 23 and the second igniter 27 are fixed in each hole. is fixed.

A cylindrical housing wall member 16 surrounding the first igniter 23 is fixed to the bottom surface 3b of the lower shell 3. Further, a dividing wall 10 is arranged between the upper shell 2 and the lower shell 3 within the housing 4. The dividing wall 10 includes a terminal end 15, a dividing wall 14 connected to the terminal end 15 and dividing the inside of the housing 4 into approximately upper and lower spaces, and a peripheral wall connected to the dividing wall 14 and extending along the housing wall member 16. 13, and an end portion 12 disposed so as to partially cover the upper opening of the housing wall member 16. A through hole 11 is formed between the upper opening and the end 12 of the housing wall member 16 to communicate the upper and lower internal spaces within the housing 4 . Furthermore, a through hole 17 is formed in the side surface of the housing wall member 16. The two spaces (first combustion chamber 21 and second combustion chamber 25) formed by being divided by the dividing wall 10 are communicated with each other by the through hole 11 and the through hole 17. Note that the through hole 17 is closed off from the inside of the housing wall member 16 with a seal tape 37 made of aluminum or the like.

Note that the periphery of the first igniter 23 within the cylindrical housing wall member 16 may be filled with a transfer charge. The transfer powder may include nitroguanidine (34% by weight) and strontium nitrate (56% by weight). Furthermore, the transfer powder can be in various shapes, such as granules, pellets, cylinders, and discs. Further, when the transfer charge is filled, the through hole 11 is covered with an aluminum tape or the like to prevent the transfer charge and the first gas generating agent 22 from being mixed together. In addition, the ignition device may be comprised only of the 1st igniter 23, and may be comprised including the 1st igniter 23 and a transfer charge.

Furthermore, the area around the second igniter 27 may be filled with a transfer charge. The transfer powder used is the same as the transfer powder described above. In addition, when the transfer charge is filled around the second igniter 27, a predetermined member is provided to separate the transfer charge and the second gas generating agent 26 so that the transfer charge and the second gas generating agent 26 do not mix. is placed. In addition, the ignition device may be comprised only of the 2nd igniter 27, and may be comprised including the 2nd igniter 27 and the transfer charge.

In the gas generator 1 according to this embodiment, the upper shell 2 is attached above the lower shell 3 with the dividing wall 10 attached to the lower shell 3 . As described above, the inner diameter of the fitting wall portion 2a of the upper shell 2 is formed larger than the inner diameter of the peripheral wall portion 2c, and the upper shell 2 continues until the abutting portion 2b abuts against the terminal end portion 15 of the dividing wall 10. It is fitted into the lower shell 3. The fitting portion and contact portion of the upper shell 2 and the lower shell 3 are joined by a suitable joining method (for example, welding) to prevent moisture from the gas generating agent filled inside.

In this way, the internal space of the housing 4 is divided into two, generally vertically, by the dividing wall 10. A first combustion chamber 21 is formed in the upper internal space of the housing 4, and a second combustion chamber 25 is formed in the lower internal space of the housing 4. A first gas generating agent 22 is arranged in the first combustion chamber 21, and a second igniter 27 and a second gas generating agent 26 are arranged in the second combustion chamber 25.

As the first gas generating agent 22, a gas generating agent having a relatively low combustion temperature is used. The combustion temperature of the first gas generating agent 22 is preferably in the range of 1000 to 1700°C. The first gas generating agent 22 may include, for example, guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), and binders and additives. Further, the first gas generating agent 22 can have various shapes, such as granules, pellets, cylinders, and disks. Note that the internal space of the housing wall member 16 may be filled with a gas generating agent having a composition different from that of the first gas generating agent 22. The gas generating agent with which the internal space of the housing wall member 16 is filled has a combustion temperature higher than that of the first gas generating agent 22 in order to promote ignition of the first gas generating agent 22 .

Similar to the first gas generating agent 22, the second gas generating agent 26 may contain guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), and a binder. Furthermore, the second gas generating agent 26 can have various shapes, such as granules, pellets, cylinders, and discs.

The first gas generating agent 22 disposed in the first combustion chamber 21 can be combusted by the operation of the first igniter 23 disposed within the housing wall member 16 . The second gas generating agent 26 disposed in the second combustion chamber 25 can be combusted by the operation of the second igniter 27 disposed within the second combustion chamber 25 . As described above, the gas generator 1 according to the present embodiment includes the first igniter 23 and the second igniter 27, and the first gas generating agent 22 and second gas generating agent arranged corresponding to each igniter. This is a dual type gas generator comprising: 26 and 26. The dual type gas generator 1 generates combustion gas to the outside by burning the first gas generating agent 22 by operating the first igniter 23 and burning the second gas generating agent 26 by operating the second igniter 27. The form of release of can be adjusted in various ways. Further, the dual type gas generator 1 can generate a relatively large amount of combustion gas and discharge it to the outside.

Further, a filter 32 is arranged in the upper internal space of the housing 4. The filter 32 has a cylindrical shape, the inside thereof is filled with the first gas generating agent 22, and the outside thereof is arranged so as to face the peripheral wall portion 2c. The filter 32 is formed by stacking stainless steel flat-knit wire meshes in the radial direction and compressing them in the radial and axial directions. The filter 32 cools combustion gas generated by combustion of the first gas generating agent 22 and the second gas generating agent 26, and collects combustion residue. Note that the filter 32 may be a wire-wound type filter formed by winding a wire around a core in multiple layers. Further, a gap 33 is formed between the peripheral wall portion 2c of the upper shell 2 and the filter 32. Gap 33 forms an annular gas passage around filter 32 . This gap 33 allows the combustion gas to pass through the entire area of the filter 32, so that effective use of the filter 32 and effective cooling and purification of the combustion gas are achieved.

Further, a cushion 31 is arranged inside the filter 32 on the inner wall side of the top surface portion 2d. The first gas generating agent 22 is filled in the first combustion chamber 21 while being pressed against the dividing wall 14 and the like by the biasing force of the cushion 31 so as not to vibrate unnecessarily. Further, a cushion 35 is arranged on the lower surface side of the dividing wall portion 14. The second gas generating agent 26 is filled in the second combustion chamber 25 while being urged by a cushion 35 so as not to vibrate unnecessarily.

Further, the gas generator 1 according to the present embodiment includes a plurality of gas exhaust ports 5 formed in the peripheral wall portion 2c of the upper shell 2. The gas generator 1 discharges combustion gas generated by burning the first gas generating agent 22 and the second gas generating agent 26 from the gas exhaust port 5. After passing through the filter 32, the combustion gas flows through the gap 33 and reaches the gas outlet 5. Before the gas generator 1 is activated, the gas exhaust port 5 is closed with an aluminum seal tape 34 to prevent moisture-containing air from entering the housing 4 from the outside. The seal tape 34 is attached to the inner wall surface of the peripheral wall portion 2c so as to close the gas discharge port 5. Note that the seal tape 34 may have a band-like shape and close the plurality of gas exhaust ports 5. Further, one gas discharge port 5 may be closed with one sheet of sealing tape 34. The gas generator 1 according to the present embodiment includes a closing portion configured with one or more seal tapes 34 that closes the plurality of gas exhaust ports 5.

In the gas generator 1 according to the present embodiment, the first igniter 23 is activated, whereby the first gas generating agent 22 is combusted and combustion gas is generated within the first combustion chamber 21 . When the pressure in the first combustion chamber 21 exceeds a predetermined value due to the combustion gas, the seal tape 34 ruptures. Further, the second igniter 27 is activated after the first igniter 23 is activated, thereby the second gas generating agent 26 is combusted and combustion gas is generated within the second combustion chamber 25. When the pressure in the second combustion chamber 25 exceeds a predetermined value due to the combustion gas, the seal tape 37 ruptures, and the first combustion chamber 21 and the second combustion chamber 25 communicate with each other. The gas generator 1 discharges combustion gas generated by combustion of the first gas generating agent 22 and the second gas generating agent 26 from the gas exhaust port 5 and supplies it to an airbag or the like.

Next, the gas exhaust port 5 will be explained based on FIG. 2. FIG. 2 is a diagram of the gas generator 1 according to the present embodiment viewed from the side of the peripheral walls 2c and 3a of the housing 4. The length of the gas discharge port 5 along the circumferential direction of the peripheral wall portion 2c of the housing 4 is longer than the length along the direction perpendicular to the circumferential direction. Here, the direction perpendicular to the circumferential direction of the peripheral wall portion 2c is a direction along the central axis of the peripheral wall portion 2c. Note that the central axis of the peripheral wall portion 2c coincides with the central axis CA of the housing 4. Hereinafter, a gas exhaust port whose length along the circumferential direction of the housing 4 is longer than the length along the direction perpendicular to the circumferential direction may be referred to as a "horizontally long gas exhaust port". Further, the plurality of gas exhaust ports 5 are arranged at equal intervals in the circumferential direction of the peripheral wall portion 2c. In this embodiment, each of the plurality of gas exhaust ports 5 is formed in an elliptical shape (track shape) whose longitudinal direction is along the circumferential direction of the peripheral wall portion 2c.

Here, the above-mentioned Patent Document 1 describes a gas ejection port in the shape of a vertically elongated hole whose width along the axial direction of the peripheral wall portion is larger than the width along the circumferential direction of the peripheral wall portion. Moreover, the above-mentioned Patent Document 2 describes a circular gas exhaust port. Generally, in a gas generator, it is preferable that the combustion gas be discharged evenly (as continuously as possible in the circumferential direction) in the circumferential direction of the outer shell container. Therefore, when a vertically elongated or circular gas outlet is formed in the peripheral wall of the outer shell container of a gas generator, in order to discharge combustion gas evenly in the circumferential direction of the outer shell container, it is necessary to It is necessary to form a large number of gas exhaust ports in a row. However, as the number of gas discharge ports increases, the processing tolerance between the plurality of gas discharge ports also increases. This is because machining tolerances occur due to the deterioration of jigs and the conditions during machining of materials, and the machining tolerances for the entire gas outlet are determined by the machining tolerances for each gas outlet and the number of gas exhaust ports. This is for the sake of coming. Furthermore, if the number of gas exhaust ports to be formed is increased, the number of man-hours required to form the gas exhaust ports increases, and the time and effort required to form the gas exhaust ports also increases. Furthermore, strength irregularities may exist at the blockage portion that blocks the gas discharge port. If the machining tolerances between multiple gas exhaust ports are large or there are irregularities in strength at the blockage, there will be differences in the bursting pressure of the blockage between the multiple gas discharge ports, which may cause problems during operation of the gas generator. Blocked portions with relatively low bursting pressure are ruptured preferentially, and combustion gas is concentrated from there. As a result, there is a possibility that a blockage having a relatively high bursting pressure may remain unruptured. If the gas generator fails to open at some of the gas discharge ports during operation, the combustion gas will be discharged unevenly in the circumferential direction of the outer shell container.

On the other hand, in the gas generator 1 according to the present embodiment, a plurality of horizontally long gas exhaust ports 5 are formed. Therefore, compared to a case where a vertically elongated hole-shaped or circular gas outlet is formed in the peripheral wall of the outer shell container, the gas generator 1 according to the present embodiment has gas discharge ports that are uniformly distributed in the circumferential direction of the outer shell container. The number of gas discharge ports 5 for discharging combustion gas (continuously in the circumferential direction) can be reduced. For example, by forming one horizontally long gas exhaust port with the same opening area as two gas exhaust ports adjacent to each other, the number of gas exhaust ports 5 to be formed can be kept small, and the number of man-hours required when forming the gas exhaust ports 5 can be reduced. be able to. Therefore, the processing tolerance between the plurality of gas discharge ports 5 can be reduced. Furthermore, when the number of gas discharge ports 5 formed is small, the number of sheets of seal tape 34 that closes the gas discharge ports 5 can be reduced, or the area of the seal tape 34 can be reduced, so that the strength of the seal tape 34 can be uneven. The possibility of this occurring can be reduced. For this reason, the gas generator 1 according to the present embodiment prevents differences in the bursting pressures of the blocked portions among the plurality of gas exhaust ports 5, and prevents the gas generator 1 from causing a difference in the bursting pressure of the blocked portions among the plurality of gas discharge ports 5, and This can reduce the possibility that the phenomenon of non-cleavage will occur. Therefore, the combustion gas can be discharged evenly in the circumferential direction of the housing 4. In addition, the gas generator 1 according to the present embodiment can reduce the number of man-hours required when forming the gas discharge port 5, so that the manufacturing process can be facilitated.

Furthermore, since the gas generator 1 according to the present embodiment can discharge combustion gas evenly in the circumferential direction of the housing 4, the flow rate of combustion gas per gas exhaust port 5 can be suppressed, and the combustion gas can be supplied. For example, it can prevent the airbag from tearing. Furthermore, the gas generator 1 according to the present embodiment, which includes a plurality of horizontally elongated gas exhaust ports 5, disperses combustion gas in the circumferential direction of the housing 4, compared to gas exhaust ports formed in a vertically elongated hole shape or a circular shape. It becomes easier to do so. Therefore, the gas generator 1 according to the present embodiment prevents the combustion gas from being discharged locally, and disperses the energy caused by the gas flow velocity and gas temperature when the combustion gas is discharged in the circumferential direction of the housing 4. The volume of combustion gas required for deployment of the airbag can be supplied to the airbag. Therefore, the gas generator 1 according to the present embodiment can suppress the influence on the airbag when exhausting combustion gas. Furthermore, even if the gas generator 1 according to the present embodiment malfunctions during transportation, the thrust forces are canceled out, so the gas generator itself will not fly off and will not affect the surroundings. Furthermore, by using the gas generator 1 according to this embodiment in an airbag system, reinforcement of the airbag can also be simplified.

Further, in the horizontally long gas discharge port 5, the stress applied to the seal tape 34 when the gas generator 1 is operated can be increased compared to a circular gas discharge port with the same area. becomes easier to cleave. Therefore, the gas generator 1 according to the present embodiment can reduce the possibility that the closed portions of some of the gas discharge ports 5 will not rupture during operation. Combustion gas can be discharged evenly. Note that the width (length in the direction along the central axis of the peripheral wall portion 2c) of the sealing tape 34 that closes the horizontally long gas discharge port 5 can also be made smaller. Therefore, in the case of housings with the same inner diameter, the size of the seal tape 34 can be made smaller compared to cases where the gas discharge port is circular or vertically long. tape melting, etc.).

<Embodiment 2>
Next, a gas generator 1 according to a second embodiment will be explained. Note that the same components as those of the gas generator 1 according to the above embodiment are given the same reference numerals, and the explanation thereof will be omitted. FIG. 3 is a diagram showing one extracted gas exhaust port 5 included in the gas generator according to the present embodiment. The gas generator according to this embodiment includes an oval gas outlet 5 similarly to the gas generator 1 according to the first embodiment. Here, as shown in FIG. 3, the gas discharge port 5 has a total length L1 in the circumferential direction such that both ends of the circumferential wall portion 2c in the circumferential direction are each semicircular. Further, the gas discharge port 5 has a hole diameter L2 as a length along the axial direction of the peripheral wall portion 2c, and a straight length L3 as the length of a linear side.

In this embodiment, based on the bursting pressure of the seal tape 34, the value of the ratio of the circumferential length of the peripheral wall 2c to the axial length of the peripheral wall 2c at each of the plurality of gas discharge ports 5 is determined. Determine a suitable range of FIG. 4 is a table showing the bursting pressure of the seal tape 34 calculated when the overall length L1, hole diameter L2, and straight length L3 of one of the gas discharge ports 5 is changed. In FIG. 4, the numerical value written in the column "Total length (mm)" is the length (mm) of the total length L1. In FIG. 4, the numerical value written in the column of "pore diameter (mm)" is the length (mm) of the pore diameter L2. In FIG. 4, the numerical value written in the "Straight length (mm)" column is the length (mm) of the straight length L3. In FIG. 4, the numerical value written in the "peripheral length (mm)" column is the circumferential length (mm) of the gas discharge port 5. In FIG. 4, the numerical value written in the column "Opening area (mm ² )" is the opening area (mm ² ) of the gas discharge port 5. In FIG. 4, the numerical value written in the "Total length/hole diameter" column is the numerical value obtained by dividing the total length L1 by the hole diameter L2, that is, the length along the circumferential direction of the peripheral wall part 2c of each of the plurality of gas discharge ports 5 and the peripheral wall part. 2c along the axial direction (hereinafter, may simply be referred to as "ratio value"). In FIG. 4, "bursting pressure (N/mm ² )" is the bursting pressure (N/mm ² ) of the sealing tape 34 that closes the gas discharge port 5.

In this embodiment, the lengths of the overall length L1, hole diameter L2, and straight length L3 were changed so that the opening area of each gas exhaust port 5 was approximately constant at about 7 mm ² . Further, as the seal tape 34, an aluminum seal tape was used. The shear strength (hereinafter referred to as "F") of the seal tape 34 was 49.1 N/mm2. Further, the thickness of the seal tape 34 (hereinafter referred to as "t") was 200 μm. If the circumference of the gas outlet 5 is expressed as "C" and the opening area of the gas outlet 5 is expressed as "S", then the bursting pressure (P) of the seal tape 34 can be calculated by the following formula (1). can.
P=F×t×C/S...(1)

The bursting pressure in Table 4 is a value calculated using the above formula (1). FIG. 5 is a graph showing the relationship between burst pressure and ratio value. In the graph of FIG. 5, the horizontal axis represents the ratio value (L1/L2), and the vertical axis represents the burst pressure. As shown in the graph of Figure 5, the burst pressure changes nonlinearly in the region where the ratio value is smaller than 2.39 (the region to the left of the dotted line), and in the region where the ratio value is larger than 2.39 (the region to the right of the dotted line). area), the burst pressure changes almost linearly. As described above, if the opening area of the gas outlet 5 is constant, the bursting pressure will be higher than when the gas outlet is circular, but if the ratio value is less than 2.4, the pressure of the sealing tape 34 will increase. It has been found that the rate of increase in burst pressure, that is, the rate of change in "burst pressure" relative to the rate of change in "total length/pore diameter" is lower.

Next, the hole diameter L2 of the gas discharge port 5 was kept constant at 2.00 mm, and the lengths of the overall length L1 and the straight length L3 were varied. FIG. 6 is a table showing the bursting pressure of the seal tape 34 calculated when the total length L1 and the straight length L3 are changed. Note that the items in the table of FIG. 6 and the table of FIG. 4 are the same. Further, similarly to the table of FIG. 4, the bursting pressure of the seal tape 34 was calculated using the above equation (1).

FIG. 7 is a graph showing the relationship between burst pressure and ratio value. In the graph of FIG. 7, the horizontal axis represents the ratio value, and the vertical axis represents the burst pressure. As shown in the graph of Figure 7, the burst pressure (P) changes nonlinearly in the region where the ratio value is smaller than 2.4 (region to the left of the dotted line), and in the region where the ratio value is larger than 2.4 (the region to the left of the dotted line). (region on the right side), the burst pressure (P) changes nearly linearly. As described above, it has been found that when the pore diameter of the gas discharge port 5 is constant, the rate of decrease in the bursting pressure of the seal tape 34 becomes high when the value of the ratio is smaller than 2.4.

If the bursting pressure of the seal tape 34 is too high, the seal tape 34 will be difficult to rupture during operation of the gas generator 1, and as a result, the timing of combustion gas discharge will be delayed, which is not preferable. For this reason, it is preferable that the value of the ratio of the gas exhaust port 5 is smaller than 2.4. In this embodiment, since the gas discharge port 5 is horizontally long, the ratio value is greater than 1. Therefore, the value of the ratio of the circumferential length of the peripheral wall 2c to the axial length of the peripheral wall 2c in each of the plurality of gas exhaust ports 5 is preferably greater than 1 and less than 2.4. preferable. Note that, from the rate of change in burst pressure (P) shown in FIGS. 5 and 7, the value of the ratio is more preferably 2.25 or less, and even more preferably 2 or less (2.00 or less). Since the gas generator 1 according to the present embodiment can keep the bursting pressure of the blocked portion within a predetermined range, there is a possibility that the blocked portion of some gas exhaust ports 5 will not burst during operation. Therefore, the combustion gas can be discharged evenly in the circumferential direction of the housing 4.

<Embodiment 3>
Next, a gas generator 1 according to a third embodiment will be explained. Note that the same components as those of the gas generator 1 according to the above embodiment are given the same reference numerals, and the explanation thereof will be omitted. FIG. 8 is a diagram of the gas generator 1 according to the present embodiment viewed from the side of the peripheral walls 2c and 3a of the housing 4. In the gas generator 1 according to the present embodiment, the plurality of gas exhaust ports include a first gas exhaust port 5A having a first opening area and a second gas exhaust port 5B having a second opening area smaller than the first opening area. It is composed of: Note that the size relationship between the first opening area and the second opening area is a size relationship obtained by comparing the opening area per gas discharge port. The first gas exhaust ports 5A and the second gas exhaust ports 5B are arranged alternately in the circumferential direction of the peripheral wall portion 2c. The gas exhaust ports 5A and 5B are formed in an oval shape. Note that each of the gas exhaust ports 5A and 5B may be formed in an oval shape, an elliptical shape, a rectangular shape, or a diamond shape.

The first gas outlet 5A and the second gas outlet 5B are closed with a seal tape 34 (not shown in FIG. 8). Here, since the second opening area is smaller than the first opening area, the seal tape 34 that closes the second gas outlet 5B has a higher bursting pressure than the seal tape 34 that blocks the first gas outlet 5A. . In this way, in the gas generator 1 according to the present embodiment, the bursting pressure of the seal tape 34 can be made different between the first gas outlet 5A and the second gas outlet 5B. Further, the gas generator 1 according to the present embodiment includes the horizontally elongated gas exhaust ports 5A and 5B, thereby reducing the possibility that the closed portions of some of the gas exhaust ports 5 will not rupture during operation. This allows the combustion gas to be discharged evenly in the circumferential direction of the housing 4.

<Embodiment 4>
Next, the gas generator 1 according to Embodiment 4 will be explained. Note that the same components as those of the gas generator 1 according to the above embodiment are given the same reference numerals, and the explanation thereof will be omitted. FIG. 9 is a diagram of the gas generator 1 according to the present embodiment viewed from the side of the peripheral walls 2c and 3a of the housing 4. In the gas generator 1 according to the present embodiment, the circumferential wall 2c has a plurality of gas discharge ports along the circumferential direction of the circumferential wall 2c at positions with different heights in the direction along the central axis of the circumferential wall 2c. 5 are arranged in two stages in the direction along the central axis of the peripheral wall portion 2c. Note that the gas exhaust port row 50 may be formed in three or more stages. The gas generator 1 according to this embodiment having such a configuration can also discharge combustion gas evenly in the circumferential direction of the housing 4.

<Modification 1>
Next, the gas generator 1 according to Modification 1 of Embodiment 4 will be described. FIG. 10 is a diagram of the gas generator 1 according to this modification as viewed from the side of the peripheral walls 2c and 3a of the housing 4. In this modification, each of the plurality of gas exhaust port rows 50 includes a first gas exhaust port 5A and a second gas exhaust port 5B. Further, the first gas outlet 5A in the upper gas outlet row 50 shown in FIG. 10 and the second gas outlet 5B in the lower gas exhaust port row 50 shown in FIG. 10 are arranged along the central axis of the peripheral wall 2c. They are arranged side by side in the same direction. Further, the second gas outlet 5B in the upper gas outlet row 50 shown in FIG. 10 and the first gas outlet 5A in the lower gas exhaust port row 50 shown in FIG. 10 are aligned along the central axis of the peripheral wall 2c. They are arranged side by side in the same direction. Note that the upper gas exhaust port row 50 and the lower gas exhaust port row 50 are arranged adjacent to each other in the vertical direction. The gas generator 1 according to the present modification configured as described above can make the total opening area of the gas exhaust ports 5A and 5B aligned in the direction along the central axis of the peripheral wall portion 2c equal. Therefore, in the gas generator 1 according to this modification, the volume of the combustion gas to be discharged is substantially constant in the circumferential direction, and the combustion gas can be discharged evenly in the circumferential direction of the housing 4.

<Modification 2>
Next, a gas generator 1 according to a second modification of the fourth embodiment will be described. FIG. 11 is a view of the gas generator 1 according to this modification as viewed from the side of the peripheral walls 2c and 3a of the housing 4. In this modification, the first gas outlet 5A and the second gas outlet 5B are formed in a rectangular shape. Note that the arrangement pattern of the first gas outlet 5A and the second gas outlet 5B is the same as in the first modification. When the first gas exhaust port 5A and the second gas exhaust port 5B are formed in a rectangular shape, it is possible to easily manage the processing jig used for forming the gas exhaust port and the formation process (control of dimensions and formation position). This makes it easier to measure the dimensions of the outlet after it is formed.

<Modification 3>
Next, a gas generator 1 according to a third modification of the fourth embodiment will be described. FIG. 12 is a diagram of the gas generator 1 according to this modification as viewed from the side of the peripheral walls 2c and 3a of the housing 4. In this modification, the gas exhaust port 5 is formed in a diamond shape, and the gas exhaust port 5 is arranged at the position of the first gas exhaust port 5A in the fourth embodiment and the first and second modified examples. In this modification, the gas exhaust ports 5 are arranged alternately (staggered) in upper and lower gas exhaust port rows 50 in the circumferential direction of the peripheral wall portion 2c. In this arrangement pattern, it is better to form the gas exhaust ports 5 in a diamond shape than to form them in a rectangular shape, even if the vertical distance between the upper and lower gas exhaust port rows 50 is shortened, the two gas discharge ports shown in FIG. The distance H between the discharge ports 5 can be increased. Here, the distance H is the distance between the two gas exhaust ports 5 where stress may be likely to be concentrated. In the gas generator 1, the longer this distance H is, the more preferable it is. According to the gas generator 1 according to the present modification, by providing the diamond-shaped gas outlet 5, it is possible to ensure a long distance H and to bring the vertical distance between the upper and lower gas outlet rows 50 closer together. can. Thereby, the gas generator 1 according to the present modification can narrow the area in which the gas outlet rows 50 are formed in the peripheral wall portion 2c.

<Embodiment 5>
Next, a gas generator 1 according to a fifth embodiment will be explained. Note that the same components as those of the gas generator 1 according to the above embodiment are given the same reference numerals, and the explanation thereof will be omitted. FIG. 13 is a diagram of the gas generator 1 according to this embodiment viewed from the side of the peripheral walls 2c and 3a of the housing 4. In the gas generator 1 according to the present embodiment, the upper gas exhaust port row 50 and the lower gas exhaust port row 50 are arranged such that they face each other across the central axis of the peripheral wall portion 2c. At least two gas exhaust ports 51, 52 are formed. The gas exhaust ports 51 and 52 are constructed by changing the overall length and hole diameter of each gas exhaust port 51 and 52 as shown in FIG. 13 while maintaining the total opening area of the gas exhaust ports in the above embodiments and modified examples. There is. Further, in this embodiment, the gas exhaust ports 51 are arranged in the upper gas exhaust port row 50, and the gas exhaust ports 52 are arranged in the lower gas exhaust port row 50.

FIG. 14 is a diagram showing the arrangement positions of the gas exhaust ports 51 and 52 when viewed from a direction along the central axis of the peripheral wall portion 2c. As shown in FIG. 14, a first imaginary line A1 connecting the centers of the two gas exhaust ports 51 and a second imaginary line A2 connecting the centers of the two gas exhaust ports 52 are both connected to the peripheral wall. 2c, and are orthogonal to each other. According to the gas generator 1 according to this embodiment, which includes the gas discharge ports 51 and 52 arranged in this manner, combustion gas can be discharged evenly in four directions. Therefore, the gas generator 1 according to this modification can discharge combustion gas evenly in the circumferential direction of the housing 4. Note that, in order to discharge the combustion gas evenly in four directions, it is preferable that the gas exhaust ports 51 and 52 have the same shape and opening area.

Further, the gas generator 1 according to the present embodiment only needs to include at least a gas exhaust port that satisfies the above-mentioned positional relationship, and further gas exhaust ports may be formed in the upper and lower rows of gas exhaust ports. .

<Embodiment 6>
Next, a gas generator 1 according to a sixth embodiment will be described. Note that the same components as those of the gas generator 1 according to the above embodiment are given the same reference numerals, and the explanation thereof will be omitted. FIG. 15 is a diagram of the gas generator 1 according to the present embodiment viewed from the top surface 2d side of the housing 4. In the gas generator 1 according to the present embodiment, the plurality of gas exhaust ports 5 are formed in a peripheral portion of the top surface portion 2d of the upper shell 2 of the housing 4 in a line in the circumferential direction. The length of the gas exhaust port 5 along the circumferential direction of the housing 4 is longer than the length along the direction perpendicular to the circumferential direction. Here, the circumferential direction of the housing 4 is a direction along the circumferential direction of the top surface portion 2d, and the direction orthogonal to the circumferential direction is a direction along the radial direction of the top surface portion 2d. The plurality of gas exhaust ports 5 are arranged at equal intervals in the circumferential direction of the top surface portion 2d. Since the gas generator 1 according to the present embodiment includes a plurality of horizontally elongated gas exhaust ports 5 similarly to the above embodiment, the combustion gas can be discharged evenly in the circumferential direction of the housing 4.

In this embodiment as well, the ratio of the length of the top surface portion 2d along the circumferential direction to the length of the top surface portion 2d along the radial direction of each of the plurality of gas exhaust ports 5 is greater than 1, and 2. It is preferably smaller than .4, more preferably 2.25 or less, and even more preferably 2 or less (2.00 or less). Since the gas generator 1 according to the present embodiment can keep the bursting pressure of the blocked portion within a predetermined range for each of the plurality of gas discharge ports 5, the blocked portions of some of the gas discharge ports 5 do not burst during operation. The possibility of this phenomenon occurring can be reduced, and the combustion gas can be discharged evenly in the circumferential direction of the housing 4.

<Other embodiments>
Although the embodiments of the present disclosure have been described above, the various embodiments described above can be combined as much as possible. The gas generator 1 according to the above embodiment and modification example is a dual type gas generator including two igniters, but the technology of the present disclosure is a single type gas generator including one igniter. It can also be applied to

Furthermore, although the gas generators according to the above embodiments and modifications have a disk shape in which the length in the height direction is shorter than the outer diameter in top view, for example, the length in the axial direction The technology of the present disclosure may be applied to a gas generator having a cylindrical shape that is longer than the outer diameter as seen.

Note that each of the plurality of gas exhaust ports 5 may be formed in an oval shape, an elliptical shape, a rectangular shape, or a diamond shape, with the longitudinal direction extending along the circumferential direction of the housing 4. The plurality of gas exhaust ports may have one type of shape among these shapes, or may have a combination of these shapes.

Further, the gas generator may include a circular gas exhaust port in addition to the horizontally long gas exhaust port. For example, the gas generator may include six horizontally long gas exhaust ports and two circular gas exhaust ports. The circular gas outlet is provided in order to reduce the pressure in the housing 4 by opening the blockage that blocks the gas outlet when the pressure in the housing 4 becomes excessive. There may be.

Each aspect disclosed herein can be combined with any other feature disclosed herein.

1: Gas generator 2: Upper shell 2c: Peripheral wall 2d: Top surface 3: Lower shell 3a: Peripheral wall 4: Housing 5, 5A, 51, 52: Gas discharge port 10: Dividing wall 14: Dividing wall 16: Housing wall member 21: First combustion chamber 22: First gas generating agent 23: First igniter 25: Second combustion chamber 26: Second gas generating agent 27: Second igniter 31, 35: Cushion 32: Filter 34 , 37 : Seal tape 50 : Gas discharge port row

Claims (5)

an outer shell container having a cylindrical peripheral wall portion, a top surface portion located at one end of the peripheral wall portion, and a bottom surface portion located at the other end of the peripheral wall portion;
an ignition device disposed within the outer shell container;
a gas generating agent disposed in the outer shell container so as to be combustible by actuation of the igniter;
a plurality of gas exhaust ports formed in the outer shell container, each of which has a length along a circumferential direction of the outer shell container that is longer than a length along a direction perpendicular to the circumferential direction;
a closing part that closes the plurality of gas exhaust ports;
Equipped with
The plurality of gas exhaust ports are formed side by side in the circumferential direction of the peripheral wall portion,
The circumferential direction of the outer shell container is the circumferential direction of the peripheral wall portion,
The direction perpendicular to the circumferential direction is a direction along the central axis of the circumferential wall,
The peripheral wall has a plurality of gas discharge ports formed by arranging the plurality of gas exhaust ports along the circumferential direction of the peripheral wall at positions having different heights in the direction along the central axis. A discharge port row is formed in a direction along a central axis of the peripheral wall,
Each of the plurality of gas outlet rows includes a first gas outlet having a first opening area, and a second gas outlet having a second opening area smaller than the first opening area. It is configured,
The first gas outlet in one gas outlet row and the second gas outlet in the gas outlet row adjacent above or below to the one gas outlet row are aligned with the central axis. They are arranged in a line along the
the second gas outlet in one of the gas outlet rows and the first gas outlet in the adjacent gas outlet row are arranged side by side in a direction along the central axis;
gas generator. The ratio of the length along the circumferential direction to the length along the direction orthogonal to the circumferential direction in each of the plurality of gas exhaust ports is greater than 1 and less than 2.4,
The gas generator according to claim 1. The first gas outlet and the second gas outlet are arranged alternately in the circumferential direction,
The gas generator according to claim 1 or claim 2 . Each of the one gas exhaust port row and the gas exhaust port row adjacent above or below to the one gas exhaust port row is arranged so as to face each other across the central axis. at least two gas outlets are formed;
A first imaginary line connecting the centers of the at least two gas outlet ports arranged in one of the gas outlet rows, and a first imaginary line connecting the centers of the at least two gas outlet ports arranged in one of the gas outlet rows; The second imaginary lines connecting each center are those that pass through the central axis and are orthogonal to each other.
A gas generator according to any one of claims 1 to 3 . Each of the plurality of gas exhaust ports is formed in an oval shape, an elliptical shape, a rectangular shape, or a diamond shape.
The gas generator according to any one of claims 1 to 4 .

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