JP7369044B2 - gas generator - Google Patents

Description

The present invention relates to a gas generator that burns a gas generating agent to generate combustion gas by operating an ignition part.

Conventionally, a combustion chamber formed in a housing is filled with a gas generating agent, and an igniter burns the gas generating agent to generate combustion gas, and the combustion gas is discharged to the outside through a gas exhaust hole provided in the housing. Gas generators that emit gas are widely used. In addition, in such a gas generator, a metal cylindrical filter may be placed between the combustion chamber and the gas exhaust hole in order to cool the generated combustion gas and collect residue. . Both axial ends of the filter are supported in abutting contact within the housing so that all of the combustion gases pass through the filter.

In connection with this, Patent Document 1 and Patent Document 2 disclose a technique in which the filling rate of a metal material in the filter is varied for each specific part in a gas generator in which a cylindrical filter is arranged. There is. In the gas generator disclosed in Patent Document 1, by lowering the filling rate of the metal material in a portion far from the gas exhaust port, the permeability of combustion gas in the portion is increased, and the combustion gas is passed through the entire filter. Furthermore, in the gas generator disclosed in Patent Document 2, in order to suppress the so-called "short pass" in which a part of the combustion gas reaches the gas exhaust hole without passing through the filter, the gas generator is filled with a metal material at both ends of the filter. By lowering the ratio and increasing its flexibility, the housing and filter are brought into close contact to prevent short paths of combustion gas.

US Patent No. 5,503,806 Japanese Patent Application Publication No. 2011-255750

Here, in the gas generator, when the gas generating agent burns and combustion gas is generated in the combustion chamber, a load acts on the filter radially outward due to the pressure of the combustion gas. If the filter is deformed by a load acting outward in the radial direction and the end of the filter separates from the housing, a short pass may occur. Therefore, there has been a need for a technique that can effectively suppress short passes caused by filter deformation.

The technology of the present disclosure was made in view of the above-mentioned circumstances, and its purpose is to provide a technology that can suppress short paths in a gas generator.

In order to solve the above problems, the gas generator of the present disclosure employs the following configuration. That is, the gas generator of the present disclosure includes a combustion chamber in which an ignition part and a gas generating agent that is combusted by the operation of the ignition part are arranged, a cylindrical peripheral wall part, and a combustion chamber provided on one end side of the peripheral wall part. A housing including a first member and a second member provided on the other end side of the peripheral wall portion and defining the combustion chamber together with the peripheral wall portion and the first member, the housing comprising: A cylindrical filter made of a metal material and having a housing formed with a gas exhaust hole communicating with the outside, and a plurality of holes, the housing surrounding the gas generating agent and having the gas exhaust hole on the outside thereof. a filter disposed in the combustion chamber so as to be located in the combustion chamber, one end surface of which is supported in contact with the first member, and the other end surface of which is supported in contact with the second member. The filter end portion, which is at least one of a first end portion of the filter that includes the one end surface and a second end portion of the filter that includes the other end surface, is formed in the housing. The holding portion contacts and supports the radially outward load acting due to combustion of the gas generating agent, and the portion of the filter is supported by the metal holding portion, which is a part of the filter that is more In the gas generator, a dense portion with a high filling rate of material is formed at a portion of the filter end that comes into contact with the holding portion.

Here, the filling rate of the metal material in a certain part of the filter refers to the proportion of the volume occupied by the metal material in the part. More specifically, it is the ratio of the volume of the metal material to the volume determined from the external shape of the part. Therefore, the fact that the filling rate of the dense part is higher than that of other parts of the filter means that the metal material that makes up the filter is packed more densely in the dense part than in other parts of the filter. means. Therefore, the dense portion has higher rigidity than other portions of the filter and is formed to be difficult to deform. Further, the dense portion of the filter is a portion where the ventilation resistance is higher than other portions of the filter because the metal material is densely packed.

According to the gas generator of the present disclosure, when a radially outward load acts on the filter due to combustion of the gas generating agent, the dense portion at the end of the filter is pressed against the holding portion. Since the dense portion is formed to be difficult to deform, the state of contact between the dense portion and the holding portion is maintained. As a result, even if the filter is deformed so as to bend outward due to the radially outward load due to combustion of the gas generating agent, the state of contact between the filter end and the housing can be maintained, and as a result, Can suppress short passes. In addition, as long as this effect is obtained, an inclusion may exist between the filter end and the holding part. Furthermore, in the present disclosure, the filter end and the holding part only need to come into contact with each other at least when the gas generator is activated (that is, when the ignition part is activated); A slight clearance may be formed between them. In other words, any material may be used as long as the filter end portion and the holding portion come into contact with each other during operation of the gas generator and the effect of suppressing short paths can be obtained.

Further, in the gas generator of the present disclosure, the filter end portion and the holding portion may be in contact with each other over the entire circumference of the filter in the circumferential direction. Thereby, short passes can be suppressed more suitably.

Furthermore, in the gas generator of the present disclosure, the filter may include a non-porous portion that does not have the pores in the dense portion. Since such a non-porous part has no voids, it has higher rigidity than other parts of the dense part and is formed to be more difficult to deform. By forming such a non-porous part in the dense part, when the gas generating agent burns, the state of contact between the dense part and the housing can be maintained more reliably, and short paths can be more effectively suppressed. .

Moreover, in the gas generator of the present disclosure, one of the first end portion and the second end portion that is closer to the gas discharge hole may be in contact with and supported by the holding portion. When the gas generating agent burns in the gas generator, the flow rate of the combustion gas that passes therethrough tends to be faster at the end closer to the gas discharge hole among both ends of the filter. That is, of both ends of the filter, the end closer to the gas discharge hole tends to receive a larger load acting radially outward due to combustion of the gas generating agent. Therefore, by setting the end of the filter closer to the gas exhaust hole as the end of the filter, short paths can be suitably suppressed.

Moreover, in the gas generator of the present disclosure, both the first end and the second end may be supported by the holding portion in contact with each other. Thereby, short passes can be suppressed more suitably.

In the gas generator of the present disclosure, at least one of the first member and the second member is connected to the peripheral wall portion and is contracted toward the outside of the combustion chamber in the axial direction of the filter. An annular inclined part that is radially inclined is formed as the holding part, and the state of contact between the holding part and the end of the filter is determined by the radially outward force exerted by the combustion of the gas generating agent. At least a portion of an end surface of the filter at the end of the filter is formed so as to be in contact with and supported from the outside in the radial direction of the filter by the holding portion so that displacement of the filter due to a load is regulated. Good too.

In the gas generator of the present disclosure, at least one of the first member and the second member has an annular step that protrudes toward the inside of the combustion chamber along the axial direction of the filter. is formed as the holding portion, and the holding portion is configured to control the outer periphery of the filter at the filter end so as to restrict displacement of the filter due to a radially outward load applied by combustion of the gas generating agent. It may be supported by abutting the surfaces.

Further, in the gas generator of the present disclosure, at least one of the first member and the second member has an annular protrusion that protrudes toward the inside of the combustion chamber in the axial direction of the filter. , the holding part is formed as the holding part, and the holding part holds the outer circumferential surface of the filter at the end of the filter so as to restrict displacement of the filter due to a radially outward load applied by combustion of the gas generating agent. It may also be supported by abutting against it.

Further, in the gas generator of the present disclosure, the holding portion is formed in both the first member and the second member, and the height of the holding portion in the axial direction of the filter is determined by the height of the holding portion in the axial direction of the filter. The structure is configured such that when the distance between the first member and the second member in the axial direction of the filter increases due to combustion, a state of contact between the holding portion and the outer circumferential surface of the filter end portion is maintained. It's okay. Thereby, even if the distance between the first member and the second member widens due to combustion of the gas generating agent, short paths can be suppressed.

Further, in the gas generator of the present disclosure, the filter has a protrusion at the end of the filter that protrudes outward in the radial direction and comes into contact with the peripheral wall, and the holding part includes the protrusion in the peripheral wall. It may be formed as a part that comes into contact with.

Further, in the gas generator of the present disclosure, a boundary between the dense portion and a portion of the filter other than the dense portion may be a boundary between the dense portion and a portion of the filter that is caused by a radially outward load acting due to combustion of the gas generating agent. The filter may be formed such that a portion of the filter other than the dense portion is supported from the outside in the radial direction of the filter by the dense portion so that displacement of the portion of the filter excluding the dense portion is regulated. good. According to this, it is possible to suppress separation of the dense part and other parts of the filter when the gas generating agent burns.

Further, in the gas generator of the present disclosure, the dense portion may be exposed only on the outer peripheral surface side of the inner peripheral surface side and the outer peripheral surface side of the filter. According to this, when the gas generating agent burns, the contact state between the dense portion and the holding portion is maintained to suppress a short pass, and the ratio of the dense portion to the entire filter can be kept small. Therefore, the combustion gas cooling function and filtering function of the filter can be largely ensured.

According to the present disclosure, short paths of combustion gas can be suppressed in a gas generator including a filter.

1 is an axial cross-sectional view of a gas generator according to Embodiment 1. FIG. 1 is a perspective view of a filter according to Embodiment 1. FIG. FIG. 3(A) is a sectional view taken along line AA in FIG. FIG. 3(B) is a sectional view taken along line BB in FIG. FIG. 2 is a diagram illustrating an example of a state in which the ignition device is activated in the gas generator according to the first embodiment and the filter is deformed due to a radially outward load due to combustion of the gas generating agent. FIG. 2 is a diagram (1) showing an example of a state in which the ignition device is activated and the housing is deformed due to combustion of the gas generating agent in the gas generator according to the first embodiment. FIG. 2 is a diagram (2) showing an example of a state in which the ignition device is activated and the housing is deformed due to combustion of the gas generating agent in the gas generator according to the first embodiment. FIG. 3 is an axial cross-sectional view of a gas generator according to Modification 1 of Embodiment 1. FIG. 3 is an axial cross-sectional view of a gas generator according to a second modification of the first embodiment. FIG. 3 is an axial cross-sectional view of a gas generator according to a third modification of the first embodiment. FIG. 6 is an axial cross-sectional view of a gas generator according to a fourth modification of the first embodiment. FIG. 7 is an axial cross-sectional view of a gas generator according to a fifth modification of the first embodiment. FIG. 7 is an axial cross-sectional view of a gas generator according to a sixth modification of the first embodiment. FIG. 7 is an axial cross-sectional view of a gas generator according to a seventh modification of the first embodiment. FIG. 3 is an axial cross-sectional view of a gas generator according to a second embodiment.

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. The invention 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 100 according to a first embodiment. In FIG. 1, the state of the gas generator 100 before operation is shown. The gas generator 100 is, for example, an airbag gas generator used for airbags.

[overall structure]
As shown in FIG. 1, the gas generator 100 includes an ignition device 4, an inner cylinder member 5, a filter 6, a transfer charge 110, a gas generating agent 120, and a housing 1 that accommodates these. There is. The gas generator 100 is configured as a so-called single-type gas generator that includes only one ignition device. Moreover, the gas generator 100 burns the gas generating agent 120 by operating the igniter 41 included in the igniter 4, and the combustion gas, which is the combustion product, is discharged through the gas exhaust hole 11 formed in the housing 1. configured to emit from. Each configuration of the gas generator 100 will be described below. Note that in this specification, for convenience, the operation of the igniter included in the ignition device (ignition unit) is expressed as “the gas generator operates” or “the ignition device (ignition unit) operates”. There is.

[housing]
The housing 1 has both ends in the axial direction closed by joining an upper shell 2 and a lower shell 3 made of metal, each formed in a substantially cylindrical shape with a bottom, with their open ends facing each other. It is formed into a short cylindrical shape. A combustion chamber 10 is formed inside the housing 1 in which an ignition device 4, an inner cylinder member 5, a filter 6, a transfer charge 110, and a gas generating agent 120 are arranged. Here, the direction along the axial direction of the housing 1 is defined as the vertical direction of the gas generator 100, the upper shell 2 side (i.e., the upper side in FIG. 1) is the upper side of the gas generator 100, and the lower shell 3 side (i.e., , the lower side in FIG. 1) is the lower side of the gas generator 100.

The upper shell 2 has a cylindrical upper peripheral wall part 21 and a top plate part 22 that closes the upper end of the upper peripheral wall part 21, thereby forming an internal space. An opening in the upper shell 2 is formed by the lower end of the upper peripheral wall 21 . A joint portion 23 extending radially outward is connected to the lower end portion of the upper peripheral wall portion 21 . The lower shell 3 has a cylindrical lower peripheral wall 31 and a bottom plate 32 that closes the lower end of the lower peripheral wall 31 and to which the ignition device 4 is fixed, forming an internal space. A joint portion 33 extending radially outward is connected to the upper end portion of the lower peripheral wall portion 31 .

The joint portion 23 of the upper shell 2 and the joint portion 33 of the lower shell 3 are overlapped and joined by laser welding or the like, thereby forming a short cylindrical housing 1 with both axial ends closed. The only places where the upper shell 2 and the lower shell 3 are joined are the joints 23 and 33. The upper peripheral wall part 21 of the upper shell 2 and the lower peripheral wall part 31 of the lower shell 3 form a cylindrical peripheral wall part 12 that connects the top plate part 22 and the bottom plate part 32. That is, the housing 1 includes a cylindrical peripheral wall 12, a top plate 22 provided at one end of the peripheral wall 12, and a bottom plate 32 provided at the other end and to which the ignition device 4 is attached. It is composed of: The combustion chamber 10 is defined by the top plate portion 22, the bottom plate portion 32, and the peripheral wall portion 12. The top plate portion 22 corresponds to a "first member" according to the present disclosure. Further, the bottom plate portion 32 corresponds to a “second member” according to the present disclosure. Further, in the upper peripheral wall portion 21 of the upper shell 2, a plurality of gas exhaust holes 11 that communicate the combustion chamber 10 with the external space of the housing 1 are formed in a line along the circumferential direction. The gas discharge hole 11 is closed with a seal tape (not shown) before the ignition device 4 is activated.

Here, the top plate portion 22 of the upper shell 2 includes a top wall portion 221 and a step portion 222. The top wall portion 221 is a portion that defines the upper end of the combustion chamber 10 and extends in the radial direction of the filter 6 so as to be orthogonal to the axial direction of the filter 6. The stepped portion 222 is an annular portion that abuts and supports the upper end portion 610 of the filter 6 against a radially outward load as described later, and is located on the inner side of the combustion chamber 10 along the axial direction of the filter 6. (ie, upward) and is connected to the peripheral wall portion 12 (upper peripheral wall portion 21). The stepped portion 222 is an annular portion formed between the top wall portion 221 and the peripheral wall portion 12, and has a crank-shaped cross section perpendicular to the circumferential direction. The inner circumferential surface 222a of the stepped portion 222 extends along the axial direction of the filter 6.

Further, the bottom plate portion 32 of the lower shell 3 includes a bottom wall portion 321 and a step portion 322. The bottom wall portion 321 is a portion that defines the lower end of the combustion chamber 10 and extends in the radial direction of the filter 6 so as to be orthogonal to the axial direction of the filter 6. A mounting hole 32 a for mounting the igniter 41 of the ignition device 4 to the bottom plate portion 32 is formed in the center of the bottom wall portion 321 . The stepped portion 322 is an annular portion that abuts and supports the lower end portion 620 of the filter 6 against a radially outward load, as will be described later, and extends toward the inside of the combustion chamber 10 along the axial direction of the filter 6. It protrudes upward (that is, upward) and is connected to the peripheral wall portion 12 (lower peripheral wall portion 31). The stepped portion 322 is an annular portion formed between the bottom wall portion 321 and the peripheral wall portion 12, and has a crank-shaped cross section perpendicular to the circumferential direction. An inner circumferential surface 322a of the stepped portion 322 extends along the axial direction of the filter 6. In the gas generator 100, the stepped portion 222 of the top plate portion 22 and the stepped portion 322 of the bottom plate portion 32 each correspond to the “holding portion” of the present disclosure.

[Ignition device]
As shown in FIG. 1, the ignition device 4 includes an igniter 41, a collar 42, and a resin portion 43, and is attached to a bottom wall portion 321 of the bottom plate portion 32 of the lower shell 3. The ignition device 4 corresponds to the "ignition section" according to the present disclosure. The igniter 41 includes a metal cup body 411 containing an igniter, and a pair of current-carrying pins 412, 412 for receiving a current supply from the outside. The igniter 41 is actuated by the ignition current supplied to the pair of current-carrying pins 412 , 412 to combust the igniter and discharge the combustion products to the outside of the cup body 411 . The collar 42 is a member that supports the igniter 41. The collar 42 is formed in a cylindrical shape, and is press-fitted into a mounting hole 32a formed in the bottom wall portion 321 and fixed by welding or the like. The resin part 43 is a resin member that is interposed between the igniter 41 and the collar 42 to fix the igniter 41 to the collar 42. The resin part 43 covers the lower part of the igniter 41 and engages with the collar 42 so that at least a part of the cup body 411 is exposed from the resin part 43. to be fixed. However, the entire cup body 411 may be overmolded with the resin portion 43. That is, the entire cup body 411 may be covered with resin. Further, the resin portion 43 forms a connector insertion space inside the collar 42 into which a connector (not shown) for supplying power from an external power source to the pair of current-carrying pins 412, 412 can be inserted. The resin portion 43 partially covers and holds the pair of current-carrying pins 412, 412 so that the lower ends of the pair of current-carrying pins 412, 412 are exposed to the connector insertion space. The resin portion 43 maintains insulation between the pair of current-carrying pins 412, 412. Note that the fixing of the igniter 41 and the collar 42 and the relationship between the collar 42 and the bottom plate portion 32 are not limited to those shown in FIG. 1, and known techniques can be used.

[Inner cylinder member]
The inner cylinder member 5 is a cylindrical member that extends from the bottom plate part 32 toward the top plate part 22 so as to surround the ignition device 4 . The inner cylindrical member 5 is formed in a cylindrical shape with one end (upper end) closed and the other end (lower end) open, and is attached to the bottom plate portion 32 by fitting (press-fitting) a collar 42 into the lower end. ing. A fire transfer chamber 51 is formed between the inner cylinder member 5 and the ignition device 4, which is a space in which the transfer charge 110 is accommodated. The transfer powder 110 is combusted by the operation of the igniter 41 and generates combustion gas and the like. In addition, a plurality of communication holes 52 are formed in the inner cylinder member 5 to communicate the inner space (namely, the fire transfer chamber 51) with the outer space. The communication hole 52 is closed with a seal tape (not shown) before the ignition device 4 is activated.

[filter]
FIG. 2 is a perspective view of the filter 6 according to the first embodiment. The filter 6 is a cylindrical member made of a metal material and has a plurality of holes. As shown in FIG. 1, the filter 6 is arranged in the combustion chamber 10 so as to surround the gas generating agent 120 and have the gas discharge holes 11 located on the outside in the radial direction. That is, the filter 6 is arranged between the gas generating agent 120 and the gas discharge hole 11 so as to surround the gas generating agent 120. Of both end faces in the axial direction, the filter 6 has one end face (an upper end face indicated by reference numeral 61) in contact with and supported by the top wall portion 221 of the top plate portion 22 of the upper shell 2, and the other end face (indicated by reference numeral 62). The lower end surface) is in contact with and supported by the bottom wall portion 321 of the bottom plate portion 32 of the lower shell 3. Thereby, the axial direction of the filter 6 is parallel to the axial direction of the housing 1 (that is, the axial direction of the peripheral wall portion).

Since the filter 6 is formed with a plurality of holes, the combustion gas from the gas generating agent 120 disposed in the combustion chamber 10 can pass through the filter 6. The filter 6 cools the combustion gas by removing heat from the combustion gas when the combustion gas passes through the filter 6 . In addition to the above-mentioned function of cooling the combustion gas, the filter 6 also has a function of filtering the combustion gas by collecting combustion residues contained in the combustion gas. In addition, in FIG. 1, the code|symbol 63 shows the inner peripheral surface of the filter 6, and the code|symbol 64 shows the outer peripheral surface of the filter 6.

FIG. 3(A) is a sectional view taken along line AA in FIG. Further, FIG. 3(B) is a sectional view taken along line BB in FIG. In FIG. 3(B), the ignition device 4 is illustrated in a simplified manner for convenience. Here, of the filter 6, the upper end 610 including the upper end surface 61 corresponds to the "first end" according to the present disclosure, and the end including the lower end surface 62 corresponds to the "lower end 620" according to the present disclosure. This corresponds to the second end. At this time, as shown in FIGS. 1 and 3(A), in the gas generator 100, the upper end portion 61
The outer circumferential surface 64 of the filter 6 at 0 is in contact with the inner circumferential surface 222a of the stepped portion 222. In other words, the stepped portion 222 contacts the upper end portion 610 from the outside in the radial direction. The upper end portion 610 of the filter 6 and the stepped portion 222 are in contact with each other over the entire circumference of the filter 6 in the circumferential direction. Further, as shown in FIGS. 1 and 3(B), in the gas generator 100, the outer circumferential surface 64 of the filter 6 at the lower end portion 620 is in contact with the inner circumferential surface 322a of the stepped portion 322. In other words, the stepped portion 322 is in contact with the lower end portion 620 from the outside in the radial direction. The lower end portion 620 of the filter 6 and the stepped portion 322 are in contact with each other over the entire circumference of the filter 6 in the circumferential direction.

As shown in FIGS. 1 and 3(A), the upper end portion 610 has a dense portion indicated by the symbol D1. The dense portion D1 is a part of the filter 6 and has a higher filling rate than other parts of the filter 6. Here, the filling rate of the metal material in a certain part of the filter refers to the proportion of the volume occupied by the metal material in the part. More specifically, it is the ratio of the volume of the metal material to the volume determined from the external shape of the part. Therefore, the fact that the filling rate of the dense part D1 is higher than that of other parts of the filter 6 means that the metal material constituting the filter 6 is more densely packed in the dense part D1 than in other parts. It means there is. Thereby, the dense portion D1 has higher rigidity than other portions of the filter 6. Further, the dense portion D1 is a portion where the ventilation resistance is higher than other portions of the filter 6 because the metal material is densely packed. The dense portion D1 of the upper end portion 610 is formed to include the upper end surface 61. Further, as shown in FIGS. 1 and 3(B), a dense portion D1 is also formed in the lower end portion 620. The dense portion D1 of the lower end portion 620 is formed to include the lower end surface 62. Here, a portion of the filter 6 other than the dense portion D1 (ie, the above-mentioned “other portion”) is referred to as a main body portion D2. In FIG. 1, the dense portion D1 and the main body portion D2 are distinguished by different hatching patterns.

The filter 6 according to this example is formed by radially stacking metal plates in which porous holes are formed and compressing them in the radial and axial directions. Examples of the porous metal plate used as the material for the filter 6 include expanded metal, lath metal, punched metal, and the like. In this example, as shown in FIG. 2, the hole H1 of the dense portion D1 is made smaller than the hole H2 of the main body portion D2, thereby making the dense portion D1 have a higher filling rate than the main body portion D2. Note that the filter 6 may be formed by molding the dense portion D1 and the main body portion D2 separately and assembling them. Further, the filter 6 may also have a wire-wound structure formed by winding wire around a core in multiple layers. In this example, the filling rate in the dense portion D1 and the filling rate in the main body portion D2 change discontinuously across the boundary, and the filling rate in the dense portion D1 is constant (uniform).

Note that in this example, the upper end 610 of the filter 6 and the stepped portion 222 of the top plate 22 are in direct contact, and the lower end 620 and the stepped portion 322 of the bottom plate 32 are in direct contact; There is no need for contact. For example, a seal member such as a gasket may be interposed between the upper end 610 of the filter 6 and the stepped portion 222 or between the lower end 620 of the filter 6 and the stepped portion 322. Moreover, the stepped portion 222 and the stepped portion 322 do not need to be formed in a continuous annular shape, but may be formed in an intermittent annular shape.

[Transmission gunpowder]
As the transfer powder 110, in addition to known black powder, a gas generating agent with good ignitability and a combustion temperature higher than that of the gas generating agent 120 can be used. The combustion temperature of the transfer powder 110 can be set in the range of 1700 to 3000°C. As such a transfer powder 110, for example, known ones containing nitroguanidine (34% by weight) and strontium nitrate (56% by weight) can be used. Furthermore, the transfer powder 110 can have various shapes, such as granules, pellets, cylinders, and disks.

[Gas generating agent]
As the gas generating agent 120, a gas generating agent having a relatively low combustion temperature can be used. The combustion temperature of the gas generating agent 120 can be set in the range of 1000 to 1700°C. As such a gas generating agent 120, a known gas generating agent including, for example, guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), and binders and additives can be used. Further, the gas generating agent 120 can have various shapes, such as granules, pellets, cylinders, and discs.

[motion]
The operation of the gas generator 100 according to the first embodiment will be described below. First, explanation will be given with reference to FIG. When a sensor (not shown) detects an impact, ignition current is supplied to the pair of current-carrying pins 412, 412, and the igniter 41 is activated. Then, the ignition powder housed in the cup body 411 of the igniter 41 is combusted, and the combustion products, such as flame and high temperature gas, are released to the outside of the cup body 411. As a result, the transfer charge 110 accommodated in the transfer chamber 51 is combusted, and combustion gas is generated. The combustion gas of the transfer charge 110 breaks the sealing tape blocking the communication hole 52 and is released from the communication hole 52 to the outside of the transfer chamber 51 . Then, the combustion gas of the transfer powder 110 comes into contact with the gas generating agent 120, and the gas generating agent 120 is ignited. As the gas generating agent 120 burns, high-temperature, high-pressure combustion gas is generated in the combustion chamber 10. As this combustion gas passes through the filter 6, the combustion gas is cooled and combustion residues are collected. The combustion gas from the gas generating agent 120 that has been cooled and filtered by the filter 6 passes through the gap 13, breaks the sealing tape blocking the gas exhaust hole 11, and is released from the gas exhaust hole 11 to the outside of the housing 1. . The combustion gas of the gas generating agent 120 is discharged to the outside of the housing 1 and then flows into an airbag (not shown). When the airbag inflates, it creates a cushion between the occupant and a rigid structure, protecting the occupant from impact.

[About short path suppression]
By the way, in a gas generator, when a gas generating agent is combusted and combustion gas is generated in a combustion chamber, a radially outward load acts on the filter due to the pressure of the combustion gas. If the filter is deformed by a load acting outward in the radial direction, and the end of the filter separates from the housing, creating a gap between the end of the filter and the housing, some of the combustion gas will pass through the filter. There is a concern that the gas may not pass through the gap and reach the gas exhaust hole. In other words, there is a possibility that a so-called "short pass" may occur.

FIG. 4 is a diagram showing an example of a state in which the ignition device 4 is activated in the gas generator 100 and the filter 6 is deformed due to a radially outward load due to combustion of the gas generating agent 120. As described above, in the gas generator 100, the stepped portion 222 contacts the upper end portion 610 from the outside in the radial direction. As a result, as shown in FIG. 4, the upper end portion 610 is supported by the stepped portion 222 while being in contact with the radially outward load due to combustion of the gas generating agent 120. More specifically, the stepped portion 222 abuts the outer circumferential surface 64 of the filter 6 at the upper end portion 610 so as to restrict displacement of the filter 6 due to a radially outward load applied by combustion of the gas generating agent 120. Furthermore, as described above, the upper end portion 610 of the filter 6 is formed with a dense portion D1 that has a higher filling rate than the main body portion D2, that is, has higher rigidity and is less likely to deform than other portions. There is. As shown in FIG. 4, the dense portion D1 is formed at a portion of the upper end portion 610 of the filter 6 that comes into contact with the stepped portion 222 due to a radially outward load due to combustion of the gas generating agent 120. Therefore, when a radially outward load acts on the filter 6 due to combustion of the gas generating agent 120, the dense portion D1 of the upper end portion 610 is pressed against the stepped portion 222, as shown in FIG. Since the dense portion D1 is more difficult to deform than the main body portion D2, the contact state between the dense portion D1 and the stepped portion 222 is maintained. Similarly, in the gas generator 100, the step portion 322 contacts the lower end portion 620 from the outside in the radial direction, so as shown in FIG. It is supported in contact with the radially outward load due to combustion. More specifically, the stepped portion 322 abuts the outer circumferential surface 64 of the filter 6 at the lower end portion 620 so as to restrict displacement of the filter 6 due to a radially outward load applied by combustion of the gas generating agent 120. I will support you. As shown in FIG. 4, a dense portion D1 is also formed at a portion of the lower end portion 620 of the filter 6 that comes into contact with the stepped portion 322 due to the radially outward load due to combustion of the gas generating agent 120. Therefore, when a radially outward load acts on the filter 6 due to combustion of the gas generating agent 120, the dense portion D1 of the lower end portion 620 is pressed against the stepped portion 322, as shown in FIG. The state of contact with the portion 322 is maintained.

Thereby, even if the upper end surface 61 and the lower end surface 62 of the filter 6 are separated from the housing 1 due to the filter 6 being deformed so as to bend outward due to combustion of the gas generating agent 120, the dense portion D1 of the upper end portion 610 The contact state between the housing 1 (top plate portion 22) and the contact state between the dense portion D1 of the lower end portion 620 and the housing 1 (bottom plate portion 32) are maintained. As a result, the contact state between the upper end 610 of the filter 6 and the housing 1 and the contact state between the lower end 620 of the filter 6 and the housing 1 are maintained, and short paths are suppressed.

Furthermore, in a gas generator, when the gas generating agent burns and combustion gas is generated in the combustion chamber, and the internal pressure of the housing that forms the combustion chamber increases, the housing may deform to expand. That is, the housing may deform to increase its volume. Here, the housing 1 of the gas generator 100 has a structure in which the top plate 22 and the bottom plate 32 are connected only by the cylindrical peripheral wall 12, and the top plate 22 and the bottom plate 32 are connected in addition to the peripheral wall 12. Since there are no connecting or fixing members, the top plate part 22 and the bottom plate part 32 tend to be more easily deformed than the peripheral wall part 12.

FIG. 5 is a diagram showing an example of a state in which the ignition device 4 is activated in the gas generator 100 and the housing 1 is deformed by combustion of the gas generating agent 120. As the internal pressure of the housing 1 increases, pressure acts on the housing 1 toward the outside of the combustion chamber 10. In other words, pressure acts on the top plate part 22 and the bottom plate part 32 in the axial direction of the filter 6 in a direction that tends to separate the top plate part 22 and the bottom plate part 32 from the end surface of the filter 6. As a result, as shown in FIG. 5, the top plate portion 22 is bent upwardly, and the bottom plate portion 32 is bent downwardly. Here, as shown in FIGS. 1 and 5, the height (protrusion amount) of the stepped portion 222 formed on the top plate portion 22 in the axial direction of the filter 6 is h1, and the stepped portion formed on the bottom plate portion 32 is Let h2 be the height (protrusion amount) of the filter 6 of 322 in the axial direction. Furthermore, the distance between the stepped portion 222 and the stepped portion 322 in the axial direction of the filter 6 in the state before the gas generator 100 is activated is d1, and the distance between the stepped portion 222 and the stepped portion 322 in the activated state of the gas generator 100 is assumed to be d1. Let the interval between the filters 6 in the axial direction be d2. When the gas generator 100 operates, the top plate part 22 bends upward, causing the stepped part 222 to move upward, and the bottom plate part 32 bends downward, causing the stepped part 322 to move downward. The distance between the stepped portion 222 and the stepped portion 322 in the axial direction of the filter 6 is increased. Therefore, d2>d1. Here, in the gas generator 100, h1 and h2 are set so that the following relational expression holds true.
h1>(d2-d1)/2...(1)
h2>(d2-d1)/2...(2)
That is, h1 and h2 are set to be larger than 1/2 of the amount of increase in the interval between the stepped portion 222 and the stepped portion 322 in the axial direction of the filter 6. Here, in FIG. 5, the stepped portion 222 of the top plate portion 22 and the stepped portion 322 of the bottom plate portion 32 are equally displaced by a displacement amount of (d2-d1)/2, and the filter 6 is displaced in the axial direction. The case where there is no deviation (no deviation) is shown. In the gas generator 100, the above-mentioned equations (1) and (2) hold, so that in the case shown in FIG. The contact state between the stepped portion 322 of the portion 32 and the lower end portion 620 is maintained, and short paths are suppressed.

Furthermore, in the gas generator 100, h1 and h2 are set so that the following relational expression holds true.
h1>d2-d1...(3)
h2>d2-d1...(4)
That is, h1 and h2 are set to be larger than the amount of increase in the interval between the stepped portion 222 and the stepped portion 322 in the axial direction of the filter 6. Here, FIG. 6 is a diagram showing an example of a state in which the ignition device 4 is activated in the gas generator 100 and the housing 1 is deformed by combustion of the gas generating agent 120. In FIG. 6, the stepped portion 222 of the top plate portion 22 and the stepped portion 322 of the bottom plate portion 32 are equally displaced by a displacement amount of (d2-d1)/2, and the lower end surface 62 is disposed on the bottom wall portion 322 of the bottom plate portion 32. A case is shown in which the filter 6 is displaced (shifted) downward in the axial direction to a position where it comes into contact with the filter 6 . In the gas generator 100, since the above equations (3) and (4) hold, even in the case shown in FIG. The state of contact with the portion 620 is maintained, and short paths are suppressed. Similarly, even when the filter 6 is displaced (shifted) upward in the axial direction to a position where the upper end surface 61 abuts against the ceiling wall portion 221 of the top plate portion 22, the contact state between the stepped portion 222 and the upper end portion 610 , and the state of contact between the stepped portion 322 and the lower end portion 620 is maintained, and short paths are suppressed.

[Action/Effect]
As described above, in the gas generator 100 according to the first embodiment, the upper end portion 610 of the filter 6 is formed in the top plate portion 22 in order to withstand the radially outward load due to combustion of the gas generating agent 120. The lower end portion 620 is in contact with and supported by the step portion 322 formed on the bottom plate portion 32 . A portion of the filter 6 is located at a portion of the upper end portion 610 of the filter 6 that contacts the stepped portion 222 of the top plate portion 22 and a portion of the lower end portion 620 that contacts the stepped portion 322 of the bottom plate portion 32. A dense portion D1 having a higher filling rate than other portions of the filter 6 is formed.

According to such a gas generator 100, even if the filter 6 is deformed so as to bend outward due to a radially outward load applied by combustion of the gas generating agent 120, the dense portion D1 of the upper end portion 610 and the housing 1, and the contact state between the closed portion D1 of the lower end portion 620 and the housing 1 can be maintained. Thereby, when the gas generating agent 120 burns, the state of contact between the upper end 610 of the filter 6 and the housing 1 and the state of contact between the lower end 620 of the filter 6 and the housing 1 can be maintained. As a result, short passes can be suppressed. Note that in this example, a case has been described in which the filter end and the holding part are in contact with each other before the gas generator is operated, but in the present disclosure, the filter end and the holding part are in contact with each other at least during the operation of the gas generator ( In other words, it is only necessary to make contact when the ignition part is activated). That is, a slight clearance may be formed between the filter end and the holding part before the gas generator is activated. The dense portion may be formed at a portion of the filter end that comes into contact with the holding portion due to a radially outward load during operation of the gas generator. This provides the effect of suppressing short paths.

In particular, in the gas generator 100, the upper end surface 61 is included in the dense portion D1 of the upper end portion 610 of the filter 6, and the lower end surface 62 is included in the dense portion D1 of the lower end portion 620 of the filter 6. The lower end surface 62 is made difficult to deform. This prevents the upper end surface 61 from deforming and creating a gap between the upper end surface 61 and the top plate part 22 and the lower end surface 62 from deforming and creating a gap between the lower end surface 62 and the bottom plate part 32. suppressed. As a result, short passes can be suppressed more suitably. Further, since the filling rate in the dense portion D1 is constant (uniform), the dense portion D1 abuts the stepped portion of the housing 1 almost evenly, and uneven contact does not occur. Thereby, the short pass prevention effect is evenly expressed in the dense portion D1.

Furthermore, in the gas generator 100, when the gap between the top plate part 22 and the bottom plate part 32 increases due to combustion of the gas generating agent 120, the stepped part 222 of the top plate part 22 and the upper end part 610 of the filter 6 come into contact with each other. The height h1 of the step portion 222 and the height h2 of the step portion 322 are set so that the contact state between the step portion 322 of the bottom plate portion 32 and the lower end portion 620 of the filter 6 is maintained. Thereby, even if the distance between the top plate part 22 and the bottom plate part 32 widens due to combustion of the gas generating agent 120, short passes can be suppressed.

Furthermore, in the gas generator 100, the upper end portion 610 of the filter 6 and the stepped portion 222 of the top plate portion 22 are in contact with each other over the entire circumference of the filter 6 in the circumferential direction. The top plate portion 22 is in contact with the stepped portion 222 over the entire circumference of the filter 6 in the circumferential direction. Thereby, short passes can be suppressed more suitably.

In addition, in this example, both the first end (upper end 610 in this example) and second end (lower end 620 in this example) of the filter are connected to the holding part (step difference in this example) formed in the housing. Although the case has been described in which the dense portion D1 is in contact with the holding portion and is supported by the holding portion, the present disclosure is not limited thereto. In the present disclosure, at least one of the first end portion and the second end portion of the filter is in contact with and supported by a holding portion formed in the housing, and a dense portion is provided at a portion of contact with the holding portion. It is enough if you have it. Further, a stepped portion serving as a holding portion may be formed in only one of the first member (top plate portion 22 in this example) and the second member (bottom plate portion 32 in this example).

Here, when the gas generating agent is combusted in the gas generator, the flow rate of the combustion gas that passes therethrough tends to be faster at the end closer to the gas discharge hole among both ends of the filter. That is, of both ends of the filter, the end closer to the gas discharge hole tends to receive a larger load acting radially outward due to combustion of the gas generating agent. Therefore, of both ends of the filter, it is preferable that at least the one closer to the gas discharge hole is in contact with and supported by the holding part, and that the part in contact with the holding part has a high filling rate. Thereby, it is possible to suitably suppress a short pass at the end on which a larger load acts among both ends of the filter. In this example, of the upper end 610 and the lower end 620 of the filter 6, at least the upper end 610, which is the one closer to the gas discharge hole 11, is supported by being in contact with the step 222, and the upper end 610 and the step 222 are in contact with each other. By forming the dense portion D1 at the abutting portion, a short path at the upper end portion 610 is suitably suppressed.

[Modification of Embodiment 1]
A gas generator according to a modification of Embodiment 1 will be described below. In the explanation of the modified example, the differences from the gas generator 100 explained in FIGS. 1 to 6 will be mainly explained, and the same reference numerals will be given to the same points as the gas generator 100, and a detailed explanation will be omitted. do. In gas generators 100A to 100G according to modifications 1 to 7 of Embodiment 1, which will be described below with reference to FIGS. 7 to 13, the upper shell 2 and lower shell 3 are joined at There are only joint parts 23 and 33, and there is no member for connecting or fixing the top plate part and the bottom plate part other than the peripheral wall part.

[Modification 1 of Embodiment 1]
FIG. 7 is an axial cross-sectional view of a gas generator 100A according to a first modification of the first embodiment. FIG. 7 shows the state of the gas generator 100A before operation. As shown in FIG. 7, the filter 6A of the gas generator 100A includes a non-porous portion N1 having no holes in the dense portion D1 of the upper end portion 610 and the dense portion D1 of the lower end portion 620. The non-porous portion N1 is filled with the metal material constituting the filter without forming any voids. Therefore, the non-porous portion N1 has a higher filling rate and therefore higher rigidity than other portions in the dense portion D1, and is more difficult to deform. By forming such a non-porous part N1 in the closed part D1, when the gas generating agent 120 burns, the contact state between the closed part D1 and the housing 1 can be maintained more reliably. As a result, short passes can be suppressed more suitably. In particular, as shown in FIG. 7, in the gas generator 100A, the upper end surface 61 is included in the non-porous portion N1 of the upper end portion 610 of the filter 6A, and the lower end surface 62 is included in the non-porous portion N1 of the lower end portion 620. This makes the upper end surface 61 and the lower end surface 62 more difficult to deform. Thereby, generation of a gap between the upper end surface 61 or the lower end surface 62 and the housing 1 due to deformation of the upper end surface 61 or the lower end surface 62 can be more preferably suppressed, and as a result, short paths can be more suitably suppressed. In addition, in the non-porous area N1 and the dense area D1 except for the non-porous area N1, the filling rate changes discontinuously at the boundary, and the filling rate in the non-porous area N1 is constant (uniform). be. Thereby, the effect of preventing short paths in the non-porous portion N1 can be evenly exhibited.

[Modification 2 of Embodiment 1]
FIG. 8 is an axial cross-sectional view of a gas generator 100B according to a second modification of the first embodiment. FIG. 8 shows the state of the gas generator 100B before operation. As shown in FIG. 8, in the filter 6B of the gas generator 100B, the dense portion D1 is formed at a position that does not include the end surfaces (upper end surface 61, lower end surface 62) of the filter. In the present disclosure, as in this gas generator 100B, the dense portion only needs to be formed at a portion that comes into contact with the holding portion (stepped portion in this example) at the end of the filter, and does not need to include the end face of the filter. good.

[Modification 3 of Embodiment 1]
FIG. 9 is an axial cross-sectional view of a gas generator 100C according to a third modification of the first embodiment. FIG. 9 shows the state of the gas generator 100C before operation. As shown in FIG. 9, in the filter 6C of the gas generator 100C, the dense portion D1 is exposed only on the outer circumferential surface 64 side of the inner circumferential surface 63 side and the outer circumferential surface 64 side of the filter 6C. That is, in the gas generator 100C, the dense portion D1 is formed in the upper end portion 610 and the lower end portion 620 of the filter 6C so that the dense portion D1 is exposed only on the side that contacts the stepped portion 222 and the stepped portion 322. . As a result, when the gas generating agent 120 burns, the contact state between the dense portion D1 and the housing 1 is maintained and a short pass is suppressed, while the ratio of the dense portion D1 to the entire filter 6C is kept small. The proportion occupied by the main body portion D2 can be increased. Therefore, the combustion gas cooling function and filtering function of the filter 6C can be largely ensured. Moreover, it can also contribute to reducing the weight of the filter 6C and the material cost.

[Modification 4 of Embodiment 1]
FIG. 10 is an axial cross-sectional view of a gas generator 100D according to a fourth modification of the first embodiment. FIG. 10 shows the state of the gas generator 100D before operation. As shown in FIG. 10, the gas generator 100D is mainly different from the gas generator 100 in that protruding walls indicated by reference numerals 223 and 323 are formed as holding portions in place of the stepped portions. The protruding wall 223 and the protruding wall 323 correspond to a "protrusion" according to the present disclosure.

As shown in FIG. 10, on the top plate 22D of the gas generator 100D, an annular protruding wall 223 extends from the top wall 221 toward the inside (i.e., the bottom) of the combustion chamber 10 in the axial direction of the filter 6. It stands out. Similarly, on the bottom plate portion 32D of the gas generator 100D, an annular protruding wall 323 protrudes from the bottom wall portion 321 toward the inside (that is, the upper side) of the combustion chamber 10 in the axial direction of the filter 6.

As shown in FIG. 10, in the gas generator 100D, the outer circumferential surface 64 of the filter 6 at the upper end 610 contacts the inner circumferential surface 223a of the protruding wall 223, and the outer circumferential surface 64 of the filter 6 at the lower end 620 contacts the protruding wall 323. It is in contact with the inner circumferential surface 323a of. That is, the protruding wall 223 contacts the upper end portion 610 from the outside in the radial direction, and the protruding wall 323 contacts the lower end portion 620 from the outside in the radial direction. As a result, the upper end portion 610 and the lower end portion 620 are supported by the protruding wall 223 and the protruding wall 323, respectively, against the radially outward load due to combustion of the gas generating agent 120. More specifically, the protruding wall 223 and the protruding wall 323 are arranged so that the outer circumferential surface 64 at the end of the filter 6 is restricted so as to restrict displacement of the filter 6 due to a radially outward load applied by combustion of the gas generating agent 120. Abut and support. A dense portion D1 is formed at a portion where the upper end portion 610 of the filter 6 contacts the protruding wall 223 and a portion where the lower end portion 620 contacts the protruding wall 323.

Even with such a gas generator 100D, when the gas generating agent 120 burns, the contact state between the end of the filter 6 and the housing 1 can be maintained by bringing the closed portion D1 into contact with the housing 1. This allows him to suppress short passes. In this example, the protruding wall 223 is integrally formed with the top wall 221 as a part of the upper shell 2, and the protruding wall 323 is integrally formed with the bottom wall 321 as a part of the lower shell 3. Such upper shell 2 and lower shell 3 can be suitably manufactured by forging or cutting.

[Modification 5 of Embodiment 1]
FIG. 11 is an axial cross-sectional view of a gas generator 100E according to a fifth modification of the first embodiment. FIG. 11 shows the state of the gas generator 100E before operation. As shown in FIG. 11, the gas generator 100E is mainly different from the gas generator 100 in that protruding pieces indicated by reference numerals 224 and 324 are attached as holding parts in place of the stepped parts. The protruding piece 224 and the protruding piece 324 correspond to a "protruding part" according to the present disclosure.

As shown in FIG. 11, the protruding piece 224 is an annular member, and is attached to the ceiling so that it protrudes from the ceiling wall portion 221 toward the inside (i.e., the lower side) of the combustion chamber 10 in the axial direction of the filter 6. It is attached to the plate portion 22E. The protruding piece 224 has an L-shaped cross-sectional shape, and one end thereof is connected to the upper peripheral wall part 21 and the other end is connected to the top wall part 221. Similarly, the protruding piece 324 is also an annular member, and is attached to the bottom plate part 32E so as to protrude from the bottom wall part 321 toward the inside (i.e., the upper side) of the combustion chamber 10 in the axial direction of the filter 6. ing. The protruding piece 324 also has an L-shaped cross-sectional shape, and one end thereof is connected to the lower peripheral wall part 31 and the other end is connected to the bottom wall part 321.

Further, as shown in FIG. 11, in the gas generator 100E, the outer circumferential surface 64 of the filter 6 at the upper end 610 contacts the inner circumferential surface 224a of the protruding piece 224, and the outer circumferential surface 64 of the filter 6 at the lower end 620 protrudes. It is in contact with the inner peripheral surface 324a of the piece 324. That is, the protruding piece 224 contacts the upper end portion 610 from the outside in the radial direction, and the protruding piece 324 contacts the lower end portion 620 from the outside in the radial direction. As a result, the protruding pieces 224 and 324 abut against the outer circumferential surface 64 at the end of the filter 6 so as to restrict displacement of the filter 6 due to a radially outward load applied by combustion of the gas generating agent 120. I will support you. A dense portion D1 is formed at a portion where the upper end portion 610 of the filter 6 contacts the protruding piece 224 and a portion where the lower end portion 620 contacts the protruding piece 324.

Such a gas generator 100E can also suppress short passes, similar to the gas generator 100D. In this example, the protruding piece 224 is formed as a separate member from other parts of the upper shell 2, and the protruding piece 324 is formed as a separate member from other parts of the lower shell 3, and the respective parts are attached separately. It is being Such an upper shell 2 and a lower shell 3 can be suitably manufactured by press-molding the parts other than the protruding pieces and assembling the protruding pieces thereto. Furthermore, if the protruding piece 224 and the top plate part 22E and the protruding piece 324 and the bottom plate part 32E are continuously welded and fixed in the circumferential direction, the effect of suppressing short paths is further enhanced.

[Variation 6 of Embodiment 1]
FIG. 12 is an axial cross-sectional view of a gas generator 100F according to a sixth modification of the first embodiment. FIG. 12 shows the state of the gas generator 100F before operation. As shown in FIG. 12, the gas generator 100F is mainly different from the gas generator 100 in that, instead of the stepped portion, inclined portions indicated by reference numerals 225 and 325 are formed as holding portions.

As shown in FIG. 12, the top plate portion 22F of the gas generator 100F has a diameter that is connected to the upper peripheral wall portion 21 and that decreases in diameter toward the outside (i.e., the upper side) of the combustion chamber 10 in the axial direction of the filter 6F. An annular sloped portion is formed. Similarly, the bottom plate portion 32F of the gas generator 100F is connected to the lower peripheral wall portion 31 and is inclined so as to decrease in diameter toward the outside (i.e., the lower side) of the combustion chamber 10 in the axial direction of the filter 6F. An annular inclined portion is formed.

The filter 6F of the gas generator 100F is supported with its upper end surface 61 in contact with the sloped portion 225 of the top plate portion 22F, and is supported with its upper end surface 61 in contact with the sloped portion 225 of the top plate portion 22F. The upper end surface 61 of the filter 6F is inclined along the inner circumferential surface 225a of the inclined portion 225 so that the diameter thereof decreases toward the tip. The lower end surface 62 of the filter 6F is inclined along the inner peripheral surface 325a of the inclined portion 325 so that the diameter thereof decreases toward the tip. That is, the inclined portion 225 contacts the upper end portion 610 from the outside in the radial direction, and the inclined portion 325 contacts the lower end portion 620 from the outside in the radial direction. As a result, the upper end portion 610 is supported by the inclined portion 225 and the lower end portion 620 is supported by the inclined portion 325, respectively, against the radially outward load due to combustion of the gas generating agent 120. In other words, the contact state between the inclined portion 225 and the upper end portion 610 and the contact state between the inclined portion 325 and the lower end portion 620 are such that the displacement of the filter 6F due to the radially outward load acting due to the combustion of the gas generating agent 120 is regulated. A state of contact is formed. A dense portion D1 is formed at a portion where the upper end portion 610 of the filter 6F contacts the inclined portion 225 and a portion where the lower end portion 620 contacts the inclined portion 325.

Even with such a gas generator 100F, when the gas generating agent 120 burns, the closed portion D1 is brought into contact with the housing 1, thereby maintaining the state of contact between the end of the filter 6F and the housing 1. I can do it. As a result, short passes can be suppressed.

Note that the filter 6F of the gas generator 100F is formed so that the length (height) in the axial direction becomes shorter from the inside to the outside in the radial direction. Such a filter 6F can be manufactured, for example, by winding an elongated porous metal plate whose width at one longitudinal end is smaller than the other end from the larger end.

[Modification 7 of Embodiment 1]
FIG. 13 is an axial cross-sectional view of a gas generator 100G according to a seventh modification of the first embodiment. FIG. 13 shows the state of the gas generator 100G before operation. As shown in FIG. 13, the gas generator 100G is mainly different from the gas generator 100 in that a part of the peripheral wall 12 is formed as a holding part instead of the stepped part.

As shown in FIG. 13, no stepped portion is formed in the top plate portion 22G of the gas generator 100G, and the top wall portion 221 is connected to the upper peripheral wall portion 21. Similarly, no stepped portion is formed in the bottom plate portion 32G of the gas generator 100G, and the bottom wall portion 321 is connected to the lower peripheral wall portion 31.

Further, the filter 6G of the gas generator 100G has a protrusion 611 that protrudes radially outward at the upper end 610. The protruding portion 611 is in contact with the inner peripheral surface 21a of the upper peripheral wall portion 21. Furthermore, the filter 6G has a protrusion 621 that protrudes radially outward at the lower end 620. The protruding portion 621 is in contact with the inner peripheral surface 31a of the lower peripheral wall portion 31. In other words, the upper peripheral wall 21 contacts the upper end 610 from the outside in the radial direction, and the lower peripheral wall 31 contacts the lower end 620 from the outside in the radial direction. As a result, the upper end portion 610 is supported by the upper peripheral wall portion 21 and the lower end portion 620 is supported by the lower peripheral wall portion 31, respectively, against the radially outward load due to combustion of the gas generating agent 120. In other words, the contact state between the upper peripheral wall part 21 and the upper end part 610, and the contact state between the lower peripheral wall part 31 and the lower end so that the displacement of the filter 6G due to the radially outward load applied by the combustion of the gas generating agent 120 is regulated. A state of contact with the portion 620 is formed. The portion of the upper circumferential wall portion 21 that abuts the protrusion 611 and the portion of the lower circumferential wall portion 31 that abuts the protrusion 621 correspond to a “holding portion” according to the present disclosure. The protruding part 611 which is the abutting part with the upper circumferential wall part 21 at the upper end part 610 of the filter 6G and the protruding part 621 which is the abutting part with the lower circumferential wall part 31 at the lower end part 620 have a dense part D1. is formed.

Even with such a gas generator 100G, when the gas generating agent 120 burns, the closed portion D1 is brought into contact with the housing 1, thereby maintaining the state of contact between the end of the filter 6G and the housing 1. I can do it. As a result, short passes can be suppressed. Further, since the protruding parts 611 and 621 formed on the filter 6G and the peripheral wall part 12 form a contact state, the shape of the housing 1 can be simplified.

Here, the filter 6G of the gas generator 100G is formed by separately molding the dense portion D1 and the main body portion D2, and then assembling them. As shown in FIG. 13, a boundary B1 between the dense portion D1 of the upper end portion 610 of the filter 6G and the main body portion D2 is an inclined surface whose diameter decreases toward the upper end surface 61. As shown in FIG. Similarly, the boundary portion B1 between the dense portion D1 and the main body portion D2 of the lower end portion 620 of the filter 6G is an inclined surface that decreases in diameter toward the lower end surface 62. Therefore, the main body portion D2 is supported by the dense portion D1 against a radially outward load. This restricts the displacement of the main body portion D2 due to the radially outward load exerted by the combustion of the gas generating agent 120. As a result, separation of the dense portion D1 and the main body portion D2 when the gas generating agent 120 burns can be suppressed. Note that the boundary part B1 between the dense part D1 and the main body part D2 is not limited to an inclined surface as shown in FIG. 13, but may be formed in a step shape.

<Embodiment 2>
FIG. 14 is an axial cross-sectional view of the gas generator 200 according to the second embodiment. FIG. 14 shows the state of the gas generator 200 before operation. The gas generator 200 according to Embodiment 2 will be explained below, focusing on the differences from the gas generator 100 according to Embodiment 1, and the same points as the gas generator 100 will be given the same reference numerals for details. I will omit the explanation. The gas generator 200 according to the second embodiment, like the gas generator 100 according to the first embodiment, does not have any member other than the peripheral wall for connecting or fixing the top plate and the bottom plate.

As shown in FIG. 14, the gas generator 200 includes a first ignition device 4X, a second ignition device 4Y, an inner cylinder member 5H, a filter 6, a transfer powder 110, a first gas generating agent 120X, It includes a second gas generating agent 120Y and a housing 1H that accommodates them. The gas generator 200 is configured as a so-called dual-type gas generator that includes two ignition devices. In the gas generator 200, the first ignition device 4X corresponds to the "ignition section" according to the present disclosure. Further, the gas generator 200 burns the first gas generating agent 120X by operating the first igniter 4X, and burns the second gas generating agent 120Y by operating the second igniter 4Y, thereby generating a relatively large amount of gas. The combustion gas is configured to be discharged from the gas exhaust hole 11. In the gas generator 200, the second ignition device 4Y operates independently of the first ignition device 4X, and when activated, it operates at a predetermined timing after the activation of the first ignition device 4X. .

As shown in FIG. 14, the housing 1H according to the second embodiment separates the internal space of the housing 1H into a first combustion chamber 10X and a second combustion chamber 10Y, and supports the lower end surface 62 of the filter 6 by contacting it. It has a partition wall part 14. The partition wall portion 14 is provided between the top plate portion 22 and the bottom plate portion 32 in the axial direction of the filter 6 . That is, the partition wall portion 14 is provided on the other end side of the peripheral wall portion 12 with respect to the top plate portion 22 provided on one end side of the peripheral wall portion 12 . A first combustion chamber 10X is defined by the top plate portion 22, the partition wall portion 14, and the peripheral wall portion 12. Further, the partition wall portion 14, the bottom plate portion 32, and the peripheral wall portion 12 define a second combustion chamber 10Y. In the gas generator 200, the top plate portion 22 corresponds to a "first member" according to the present disclosure, and the partition wall portion 14 corresponds to a "second member" according to the present disclosure. The first combustion chamber 10X accommodates a first gas generating agent 120X that is combusted by the operation of the first igniter 4X, and the second combustion chamber 10Y houses a second gas generating agent 120X that is combusted by the operation of the second igniter 4Y. agent 120Y is accommodated. The first combustion chamber 10X corresponds to a "combustion chamber" according to the present disclosure, and the first gas generating agent 120X corresponds to a "gas generating agent" according to the present disclosure.

The partition wall section 14 includes a dividing wall section 141, a fitting wall section 142, and a terminal end section 143. The dividing wall portion 141 is a portion that defines the lower end of the first combustion chamber 10X, and extends in the radial direction of the filter 6 so as to be orthogonal to the axial direction of the filter 6. A through hole 14a, which is a hole through which the inner cylinder member 5 passes, is formed in the dividing wall portion 141. The fitting wall portion 142 is a cylindrical portion that fits into the lower peripheral wall portion 31 of the lower shell 3, and extends from the peripheral edge of the dividing wall portion 141 toward the inside of the first combustion chamber 10X along the axial direction of the filter 6. (i.e., upward). The terminal end portion 143 is an annular portion placed on the upper end of the lower peripheral wall portion 31 of the lower shell 3, and extends radially outward from the upper end of the fitting wall portion 142.

The inner cylinder member 5H according to the second embodiment extends from the bottom plate part 32 toward the top plate part 22 so as to surround the first ignition device 4X fixed to the bottom plate part 32, and penetrates through the through hole 14a of the partition wall part 14. The end is open. Therefore, the space inside the inner cylinder member 5H is included in the first combustion chamber 10X, and the first ignition device 4X is disposed in the first combustion chamber 10X. Moreover, a partition member P1 is arranged inside the inner cylinder member 5H to partition the internal space into upper and lower parts. As a result, the space below the partition member P1 (on the first ignition device 4X side) in the internal space of the inner cylinder member 5 is formed as a fire transfer chamber 51. The transfer chamber 51 accommodates the transfer powder 110 without being mixed with the first gas generating agent 120X. The partition member P1 is formed of a material that is quickly combusted, melted, or extinguished by the combustion gas of the transfer charge 110 so as not to prevent the combustion gas of the transfer charge 110 from igniting the first gas generating agent 120X. In addition, a plurality of communication holes 52 are formed in the inner cylinder member 5H to communicate the internal space of the inner cylinder member 5H (and thus the first combustion chamber 10X) and the second combustion chamber 10Y. The communication hole 52 is closed with a seal tape (not shown) before the second ignition device 4Y is activated.

As shown in FIG. 14, in the gas generator 200, the filter 6 is supported with its upper end surface 61 in contact with the top plate section 22, and with its lower end surface 62 in contact with the dividing wall section 141 of the partition wall section 14. It is arranged in the first combustion chamber 10X so that the first combustion chamber 10X Furthermore, in the gas generator 200, the stepped portion 222 of the top plate portion 22 contacts the upper end portion 610 from the outside in the radial direction, and the fitting wall portion 142 of the partition wall portion 14 contacts the lower end portion 620 from the outside in the radial direction. are in contact. As a result, the upper end 610 of the filter 6 is supported by the stepped portion 222 and the lower end 620 is supported by the fitting wall 142, respectively, against the radially outward load due to combustion of the gas generating agent 120. . In the gas generator 200, the step portion 222 and the fitting wall portion 142 correspond to the “holding portion” according to the present disclosure. A dense portion D1 is formed at a portion where the upper end portion 610 of the filter 6 contacts the stepped portion 222 and a portion where the lower end portion 620 contacts the fitting wall portion 142.

When such a gas generator 200 operates, first, the first igniter 4X operates, the transfer charge 110 accommodated in the transfer chamber 51 of the first combustion chamber 10X burns, and combustion gas is generated. . When the partition member P1 is burned by the combustion gas of the first transfer powder 111 and removed, the combustion gas comes into contact with the first gas generating agent 120X, and the first gas generating agent 120X is ignited. Combustion gas is generated in the first combustion chamber 10X by burning the first gas generating agent 120X. The combustion gas of the first gas generating agent 120X passes through the filter 6 and is discharged from the gas discharge hole 11 to the outside of the housing 1. Next, the second igniter 4Y is activated, the second gas generating agent 120Y accommodated in the second combustion chamber 10Y is combusted, and combustion gas is generated. The combustion gas from the second gas generating agent 120Y breaks the seal tape that was blocking the communication hole 52, flows into the first combustion chamber 10X from the communication hole 52, passes through the filter 6, and blocks the gas discharge hole 11. The gas is released from the housing 1H through the gas discharge hole 11 by tearing the seal tape.

In the gas generator 200 according to the second embodiment, when a radially outward load acts on the filter 6 due to combustion of the first gas generating agent 120X and the second gas generating agent 120Y, the dense portion D1 of the upper end portion 610 becomes a stepped portion. 222, and the dense portion D1 of the lower end portion 620 is pressed against the fitting wall portion 142. Thereby, the dense portion D1 and the housing 1H come into contact with each other, and the state of contact between the end of the filter 6 and the housing 1H can be maintained. As a result, short passes can be suppressed.

<Others>
Although preferred embodiments of the present disclosure have been described above, each aspect disclosed herein can be combined with any other feature disclosed herein.

100,200 Gas generator 1 Housing 11 Gas discharge hole 12 Surrounding wall portion 14 Partition wall portion (an example of the second member)
142 Step part 2 Upper shell 22 Top plate part (an example of the first member)
222 Step part (example of holding part)
3 Lower shell 32 Bottom plate part (an example of the second member)
322 Step part (example of holding part)
4 Ignition device (an example of an ignition part)
5 Inner cylinder member 6 Filter 61 Upper end surface (one end surface of filter)
62 Lower end surface (other end surface of filter)
64 Outer peripheral surface 610 of filter Upper end (first end)
620 Lower end (second end)
10 Combustion chamber 120 Gas generating agent D1 Closed part N1 Non-porous part

Claims (10)

a combustion chamber in which an ignition part and a gas generating agent that is combusted by the operation of the ignition part are arranged;
a cylindrical peripheral wall, a first member provided at one end of the peripheral wall, and a second member provided at the other end of the peripheral wall and defining the combustion chamber together with the peripheral wall and the first member. a housing including a member, the housing having a gas exhaust hole that communicates the combustion chamber with the outside of the housing;
A cylindrical filter having a plurality of holes and made of a metal material, the filter is arranged in the combustion chamber so as to surround the gas generating agent and the gas discharge hole is located on the outside thereof, and one end surface thereof is a filter that is supported in contact with the first member and whose other end surface is supported in contact with the second member;
A gas generator comprising:
Both ends of the filter are supported by holding portions formed in the housing in contact with a radially outward load acting due to combustion of the gas generating agent,
A dense portion, which is a partial portion of the filter and has a higher filling rate of the metal material than other portions of the filter, is formed at a portion of each of the both end portions of the filter that comes into contact with the holding portion. ing,
gas generator. Each of the end portions of the filter and the holding portion are in contact with each other over the entire circumference of the filter in a circumferential direction,
The gas generator according to claim 1. The filter includes a non-porous portion having no pores in the dense portion.
The gas generator according to claim 1 or 2. At least one of the first member and the second member has an annular inclined portion that is connected to the peripheral wall portion and that is inclined such that the diameter thereof decreases toward the outside of the combustion chamber in the axial direction of the filter. is formed as the holding portion,
The state of contact between the holding portion and each of the both end portions of the filter is such that displacement of the filter due to a radially outward load applied by combustion of the gas generating agent is regulated . At least a portion of the end face of the filter at each of both ends is formed so as to be in contact with and supported by the holding portion from the outside in the radial direction of the filter;
A gas generator according to any one of claims 1 to 3 . An annular stepped portion protruding toward the inside of the combustion chamber along the axial direction of the filter is formed on both the first member and the second member as the holding portion,
The holding portion abuts and supports the outer circumferential surface of the filter at each of the both ends of the filter so as to restrict displacement of the filter due to a radially outward load applied by combustion of the gas generating agent. do,
A gas generator according to any one of claims 1 to 3 . An annular protrusion protruding toward the inside of the combustion chamber in the axial direction of the filter is formed on both the first member and the second member as the holding portion,
The holding portion abuts and supports the outer circumferential surface of the filter at each of the both ends of the filter so as to restrict displacement of the filter due to a radially outward load applied by combustion of the gas generating agent. do,
A gas generator according to any one of claims 1 to 3 . The height of the holding part in the axial direction of the filter is such that when the distance between the first member and the second member in the axial direction of the filter increases due to combustion of the gas generating agent, the height of the holding part and the filter increases. It is set so that the state of contact with the respective outer circumferential surfaces of the both ends of is maintained;
The gas generator according to claim 5 or 6 . The filter has a protrusion that protrudes radially outward and comes into contact with the peripheral wall at each of the ends of the filter,
The holding portion is formed as a portion of the peripheral wall that abuts the protrusion,
A gas generator according to any one of claims 1 to 3 . The boundary between the dense portion and the portion of the filter other than the dense portion is determined by the displacement of the portion of the filter excluding the dense portion due to a radially outward load acting due to combustion of the gas generating agent. is formed such that a portion of the filter other than the dense portion is supported from the outside in the radial direction of the filter by the dense portion, so that the filter is regulated;
A gas generator according to any one of claims 1 to 8 . a combustion chamber in which an ignition part and a gas generating agent that is combusted by the operation of the ignition part are arranged;
a cylindrical peripheral wall, a first member provided at one end of the peripheral wall, and a second member provided at the other end of the peripheral wall and defining the combustion chamber together with the peripheral wall and the first member. a housing including a member, the housing having a gas exhaust hole that communicates the combustion chamber with the outside of the housing;
A cylindrical filter having a plurality of holes and made of a metal material, the filter is arranged in the combustion chamber so as to surround the gas generating agent and the gas discharge hole is located on the outside thereof, and one end surface thereof is a filter that is supported in contact with the first member and whose other end surface is supported in contact with the second member;
A gas generator comprising:
A filter end that is at least one of a first end that is a part of the filter that includes the one end surface and a second end that is a part that includes the other end surface of the filter is formed in the housing. supported by the holding portion in contact with a radially outward load acting due to combustion of the gas generating agent;
Some parts of the filter are filled with the metal material more than other parts of the filter.
A dense portion with a high ratio is formed at a portion of the end portion of the filter that comes into contact with the holding portion,
The dense portion is exposed only on the outer circumferential surface side of the inner circumferential surface side and the outer circumferential surface side of the filter ,
gas generator.

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