Gas generator and airbag module assembly

Abstract

The gas generator according to the present invention is provided with a temperature rise suppressing member provided in contact with an outer surface of a housing so as to cover at least a part of the outer surface, the temperature rise suppressing member including: a heat absorber that causes a chemical change or a state change by heat of the housing when the temperature of the housing rises due to combustion of a gas generating agent; heat of the shell is absorbed; and an adhesive coexisting with the heat absorbing agent so that the temperature rise suppressing member is flexible.

Description

Technical Field

[0001] The present invention relates to a gas generator and an air bag module assembly. Background Art

[0002] Inflators are well known for containing a gas generating agent in a housing. An igniter causes the gas generating agent to combust to generate gas, which is then discharged outside the housing. Such inflators are used, for example, to supply gas to airbags and seat belt retractors in automobiles.

[0003] When the gas generator is operating, the combustion heat of the gas generant is conducted, causing the surface of the housing to reach a high temperature. For example, when the gas generator is activated to inflate and deploy the airbag, if the airbag comes into contact with the hot housing, there is a concern that thermal effects may affect surrounding components, such as melting the airbag. In this regard, a gas generator is disclosed that suppresses the rise in the surface temperature of the housing by providing a thermally insulating member on the surface of the housing (e.g., Patent Document 1).

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2002-326553 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] In order to more effectively suppress the temperature increase of the housing after the gas generator is operated, it is important to provide a member for suppressing the temperature increase on the housing with good adhesion.

[0009] The technology disclosed herein has been developed in view of the above circumstances, and an object of the technology is to provide a technology capable of more efficiently suppressing a temperature increase of the casing after the operation of the gas generator.

[0010] Solution to the problem (Solution 1)

[0011] To address the aforementioned issues, a gas generator according to one embodiment of the present disclosure employs the following configuration. Specifically, the gas generator comprises: a gas generator that generates gas upon combustion; a metal housing that houses the gas generator and is formed with a gas discharge hole for discharging the gas generated by the combustion of the gas generator to the outside; an ignition device that ignites the gas generator upon operation; and a temperature rise suppression member disposed in contact with the outer surface of the housing, covering at least a portion of the outer surface of the housing. The temperature rise suppression member includes a heat absorber that absorbs heat from the housing by chemically changing or changing state due to the heat of the housing when the temperature of the housing rises due to the combustion of the gas generator; and an adhesive that is present together with the heat absorber to impart flexibility to the temperature rise suppression member.

[0012] (Scheme 2)

[0013] In the above solution 1, the adhesive may be mixed with the heat absorbent.

[0014] (Scheme 3)

[0015] In the above embodiment 1 or 2, the heat absorbent may include at least one selected from the group consisting of fatty acid polycarbonate, magnesium carbonate, fumaric acid, and terephthalic acid.

[0016] (Scheme 4)

[0017] In any one of the above-mentioned aspects 1 to 3, the binder may include a compound having a hydroxyl group or a carbonyl group.

[0018] (Scheme 5)

[0019] In any one of the above aspects 1 to 4, the content ratio of the heat absorbent in the temperature rise suppression member may be 70% to 95%, and the content ratio of the binder in the temperature rise suppression member may be 5% to 30%.

[0020] (Scheme 6)

[0021] In any one of the above-mentioned schemes 1 to 5, the shell may have: a cylindrical peripheral wall portion, on which the gas exhaust hole is formed; a first closing portion, which closes one end of the peripheral wall portion; and a second closing portion, which closes the other end of the peripheral wall portion; the gas exhaust hole is formed at a position in the axial direction of the shell where the distance between the gas exhaust hole and the first closing portion is shorter than the distance between the gas exhaust hole and the second closing portion, and the temperature rise suppression member is arranged on the outer surface of the first closing portion.

[0022] (Scheme 7)

[0023] In any one of the above-mentioned aspects 1 to 6, the housing may include a cylindrical peripheral wall portion in which the gas discharge hole is formed, and the temperature rise suppression member may be provided on an outer surface of the peripheral wall portion.

[0024] (Scheme 8)

[0025] In any one of the above-mentioned aspects 1 to 7, a portion of the outer surface of the housing that contacts the temperature-rise suppression member may be formed in a concavo-convex shape.

[0026] (Scheme 9)

[0027] In any one of the above-mentioned aspects 1 to 8, a label sheet displaying predetermined information may be further provided, wherein the label sheet is attached to the temperature-rise suppression member so that the temperature-rise suppression member is sandwiched between the label sheet and the housing.

[0028] (Scheme 10)

[0029] Furthermore, the technology disclosed herein can also be defined as an airbag module assembly including a gas generator. Specifically, one aspect of the disclosure may be an airbag module assembly including: the gas generator of aspect 6; and an airbag disposed in a folded state and inflated and deployed by the gas discharged from the gas discharge hole; the gas generator being disposed such that the first sealing portion faces the folded airbag.

[0030] (Scheme 11)

[0031] In addition, the airbag module assembly of one embodiment of the present disclosure may also include: the gas generator of the above-mentioned embodiment 7; and an airbag, which is configured in a folded state and is inflated and expanded by the gas discharged from the gas discharge hole; the gas generator is configured in such a manner that the peripheral wall portion is opposite to the airbag in the folded state, and the temperature rise suppression component is arranged on the outer surface of a portion of the peripheral wall portion opposite to the airbag.

[0032] Effects of the Invention

[0033] According to the present disclosure, it is possible to more efficiently suppress a rise in the temperature of the casing after the gas generator is activated. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is a cross-sectional view showing a state before operation of the airbag module assembly including the gas generator according to the first embodiment.

[0035] Figure 2 This is a cross-sectional view showing the state of the gas generator according to Embodiment 1 before operation.

[0036] Figure 3This is a partially enlarged view of a gas generator according to Modification 1 of Embodiment 1.

[0037] Figure 4 This is a cross-sectional view showing a state before operation of an airbag module assembly including a gas generator according to a second modification of the first embodiment.

[0038] Figure 5 This is a cross-sectional view showing a state of a gas generator according to a second modification of the first embodiment before operation.

[0039] Figure 6 This is a cross-sectional view showing a state before operation of an airbag module assembly including the gas generator according to the second embodiment.

[0040] Figure 7 This is a cross-sectional view showing the state of the gas generator according to Embodiment 2 before operation. DETAILED DESCRIPTION

[0041] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. In the embodiments described below, a scheme for applying the technology of the present disclosure to a gas generator (inflator) for an airbag will be described. However, the use of the technology of the present disclosure is not limited thereto, and for example, it can also be applied to a gas generator for a seat belt retractor. It should be noted that each structure in each embodiment and their combination are examples, and additions, omissions, replacements, and other changes to the structure can be appropriately made without departing from the scope of the subject matter of the present invention. The present disclosure is not limited to the embodiments, but only to the claims.

[0042] <Implementation Method 1>

[0043] Figure 1 1 is a cross-sectional view showing a state before operation of an airbag module assembly 1000 including the airbag gas generator (hereinafter referred to as simply a gas generator) 100 according to the first embodiment. Figure 2 : is a cross-sectional view showing the state of the gas generator 100 before operation according to the first embodiment. Figure 1 and Figure 2 , a cross section along the central axis A1 of the housing shown by reference numeral 1 is shown. Here, the direction along the central axis A1 of the housing 1 (axial direction) is defined as the vertical direction of the gas generator 100, and the vertical direction of the gas generator 100 is defined as the vertical direction of the gas generator 100. Figure 2 The upper shell side shown by the reference numeral 2 (ie, Figure 2 The upper side of the gas generator 100 is used as the upper side of the gas generator 100. Figure 2 The lower housing side shown by reference numeral 3 (ie, Figure 2The lower side of the gas generator 100 is referred to as the lower side of the gas generator 100. It should be noted that, in this specification, for convenience, the operation of the igniter included in the ignition device of the gas generator is sometimes expressed as "ignition device operation", "gas generator operation" or "airbag module assembly operation".

[0044] [Overall composition]

[0045] like Figure 1 As shown, the airbag module assembly 1000 includes a gas generator 100, an airbag 200, and a module box 300 for accommodating them. The airbag module assembly 1000 is, for example, an airbag device for frontal collision protection (so-called front airbag device), which is mounted on a vehicle and protects the occupants from impact by inflating and deploying the airbag 200 when the vehicle is involved in a frontal collision. However, the airbag module assembly of the present disclosure is not limited to a front airbag device. The airbag module assembly may be, for example, an airbag device for side collision protection (so-called side airbag device), which protects the occupants from impact by inflating and deploying the airbag when the vehicle is involved in a side collision. In addition, as an example, the airbag module assembly 1000 of this embodiment is arranged on the driver's seat (more specifically, the steering wheel) of the vehicle, but the airbag module assembly of the present disclosure may also be arranged on, for example, the dashboard of the passenger seat or other parts.

[0046] The gas generator 100 is a gas supply source for inflating the airbag 200. The gas generator 100 is configured to operate when, for example, a vehicle sensor (not shown) senses an impact, and discharge gas to the outside. Details of the gas generator 100 will be described later.

[0047] The airbag 200 is a bag body that is expanded by supplying gas from the gas generator 100. The airbag 200 is made of polyamide, for example. Figure 1 As shown, before the gas generator 100 is operated, it is housed in the module box 300 in a folded state.

[0048] The module box 300 is a box body that houses the gas generator 100 and the airbag 200. The module box 300 includes an airbag cover 400 and a back plate 500. The airbag cover 400 includes a cylindrical wall portion 401 that forms the side of the module box 300, and a front portion 402 that closes one end of the wall portion 401 and forms the front of the module box 300. The airbag cover 400 is formed to be combined with, for example, a steering wheel of a vehicle. The back plate 500 includes a cylindrical wall portion 501 that, by being fixed to the wall portion 401 of the airbag cover 400, forms the side of the module box 300 together with the wall portion 401, and a back portion 502 that closes one end of the wall portion 501 and forms the back of the module box 300. The back portion 502 has a mounting hole 502a formed therein for mounting the gas generator 100. The airbag 200 is connected to the gas generator 100 and is arranged in a folded state between the gas generator 100 and the front portion 402 of the module box 300 .

[0049] The airbag module assembly 1000 is installed in the vehicle so that the front portion 402 of the airbag cover 400 faces the occupant (in this example, the driver), who is protected by the airbag 200. When the inflator 100 is activated, the front portion 402 ruptures due to the pressure generated by the expansion of the airbag 200. This causes the airbag 200 to fly out of the module case 300 and deploy in front of the occupant, thereby protecting the occupant from impact.

[0050] [Gas generator]

[0051] like Figure 2 As shown, the gas generator 100 of embodiment 1 is formed into a short-sized cylindrical shape (disc-shaped) and includes an ignition device 4, an inner cylindrical member 5, a filter 6, a first gas generating agent 110, a second gas generating agent 120, a metal shell 1 for accommodating them, and a temperature rise suppression member 7 provided on the outer surface of the shell 1. The gas generator 100 is configured as a so-called single-stage gas generator having only one ignition device. In addition, the gas generator 100 is configured as a so-called pyrotechnic gas generator that uses only a gas generating agent as a gas source. However, the gas generator disclosed in the present invention is not limited to the above-mentioned gas generator. The gas generator disclosed in the present invention may have multiple ignition devices, or may be configured as a so-called hybrid gas generator that uses a gas generating agent and pressurized gas as a gas source.

[0052] Gas generator 100 is configured such that igniter 41 included in ignition device 4 is activated to combust first gas generating agent 110 and second gas generating agent 120, and combustion gas, a combustion product thereof, is discharged from gas discharge hole 11 formed in housing 1. The components of gas generator 100 are described below.

[0053] [shell]

[0054] The housing 1 comprises an upper shell 2 and a lower shell 3, each of which is formed into a generally cylindrical shape with a bottom. The upper shell 2 and the lower shell 3 are joined with their open ends facing each other, resulting in a short cylindrical shape with both axial ends closed. The housing 1 is made of metal. The metal material forming the housing 1 is not particularly limited; for example, stainless steel can be used. The interior space of the housing 1 forms a combustion chamber 10, in which an ignition device 4, an inner cylindrical member 5, a filter 6, a first gas generant 110, and a second gas generant 120 are located.

[0055] The upper housing 2 includes a cylindrical upper circumferential wall portion 21 and a top plate portion 22 that closes the upper end of the upper circumferential wall portion 21, thereby forming an internal space. The lower end of the upper circumferential wall portion 21 forms an opening of the upper housing 2. A flange-shaped joint portion 23 extending radially outward is connected to the lower end of the upper circumferential wall portion 21. The lower housing 3 includes a cylindrical lower circumferential wall portion 31 and a bottom plate portion 32 that closes the lower end of the lower circumferential wall portion 31 and fixes the ignition device 4, thereby forming an internal space. A mounting hole 32a for mounting the ignition device 4 is formed in the bottom plate portion 32. A flange-shaped joint portion 33 extending radially outward is connected to the upper end of the lower circumferential wall portion 31.

[0056] The upper housing 2 and lower housing 3 can be formed, for example, by stamping stainless steel. The joint 23 of the upper housing 2 and the joint 33 of the lower housing 3 are joined by laser welding or other methods after being superimposed, thereby forming a short cylindrical housing 1 with both ends closed in the axial direction. The upper peripheral wall 21 of the upper housing 2 and the lower peripheral wall 31 of the lower housing 3 form a cylindrical peripheral wall 12 connecting the top plate 22 and the bottom plate 32. Specifically, the housing 1 comprises: a cylindrical peripheral wall 12; a top plate 22 that closes one end of the peripheral wall 12; and a bottom plate 32 that closes the other end of the peripheral wall 12 and is mounted with the ignition device 4. The top plate 22, bottom plate 32, and peripheral wall 12 define a combustion chamber 10. The central axis of the peripheral wall 12 constitutes the central axis A1 of the housing 1. The top plate 22 is an example of the "first closed portion" in this disclosure. In addition, the bottom plate portion 32 is an example of a “second closing portion” in the present disclosure.

[0057] In addition, if Figure 2 As shown, a plurality of gas discharge holes 11 are formed side by side along the circumferential direction on the peripheral wall portion 12 (more specifically, the upper peripheral wall portion 21 of the upper shell 2) to connect the combustion chamber 10 with the external space of the outer shell 1. Before the ignition device 4 is operated, the gas discharge holes 11 are sealed with a sealing tape (not shown).

[0058] In addition, if Figure 2As shown, the outer surface of the housing 1 is denoted by reference numeral S1, specifically, the surface on the opposite side to the surface that defines the internal space (combustion chamber 10) of the housing 1. The outer surface S1 is the surface facing the outside of the gas generator 100. Further, the surface of the peripheral wall portion 12 in the outer surface S1 is taken as the outer surface S12, the surface of the top plate portion 22 is taken as the outer surface S22, and the surface of the bottom plate portion 32 is taken as the outer surface S32.

[0059] As Figure 1 shown, in a state where the gas discharge hole 11 and the top plate portion 22 of the housing 1 are inserted into the interior of the module box 300 from the mounting hole 502a of the module box 300, the flange portions (joint portions 23, 33) of the housing 1 are fixed to the back surface portion 502, whereby the gas generator 100 is mounted on the back plate 500. In the airbag module assembly 1000, the gas discharge hole 11 and the top plate portion 22 of the housing 1 are located inside the module box 300, and the bottom plate portion 32 is located outside the module box 300. The gas generator 100 is arranged such that the top plate portion 22 of the housing 1 faces the airbag 200.

[0060] Here, as Figure 2 shown, the distance in the axial direction (in this example, the vertical direction) of the housing 1 between the gas discharge hole 11 and the top plate portion 22 is set as d1, and the distance in the axial direction of the housing 1 between the gas discharge hole 11 and the bottom plate portion 32 is set as d2. Here, the gas discharge hole 11 is formed at a position where d1 is shorter than d2 in the axial direction of the housing 1. That is, the gas generator 100 of the present embodiment is configured such that d1 < d2. Therefore, the gas discharge hole 11 is formed at a position closer to the top plate portion 22 than to the bottom plate portion 32. In the gas generator 100, the gas discharge hole 11 is formed at a position closer to the top plate portion 22, which is the side where the airbag 200 is arranged, in the top plate portion 22 and the bottom plate portion 32, so as to facilitate the supply of gas to the airbag 200.

[0061] [Ignition device]

[0062] As Figure 2As shown, the ignition device 4 includes an igniter 41, a collar 42, and a resin portion 43. The igniter 41 is mounted on the bottom plate 32 of the lower housing 3. The igniter 41 has a metal cup 411 containing a primer and a pair of current-carrying pins 412, 412 for receiving an external current supply. The igniter 41 is operated by an ignition current supplied to the pair of current-carrying pins 412, 412, thereby causing the primer to combust and discharging its combustion products outside the cup 411. The collar 42 is a metal member that supports the igniter 41. The collar 42 is cylindrical and is secured by welding or other means by being press-fitted into the mounting hole 32a formed in the bottom plate 32. The resin portion 43 is a resin member that is sandwiched between the igniter 41 and the collar 42 to secure the igniter 41 to the collar 42. The resin portion 43 covers the lower portion of the igniter 41 and engages with the collar 42, thereby fixing the igniter 41 relative to the collar 42 in a manner that at least a portion of the cup body 411 is exposed from the resin portion 43. However, the entire cup body 411 may be overmolded by the resin portion 43. That is, the entire cup body 411 may also be in a state covered by resin. In addition, the resin portion 43 forms a connector insertion space on the inner side of the collar 42 into which a connector (not shown) is inserted, which supplies electricity from an external power supply to a pair of power pins 412, 412. The resin portion 43 covers and holds a portion of the pair of power pins 412, 412 in a manner that the lower ends of the pair of power pins 412, 412 are exposed to the connector insertion space. The pair of power pins 412, 412 are insulated from each other by the resin portion 43. It should be noted that the fixation of the igniter 41 to the collar 42 and the relationship between the collar 42 and the bottom plate portion 32 are not limited to Figure 2 , known techniques can be used.

[0063] [Inner cylinder member]

[0064] The inner cylinder member 5 is a cylindrical metal member that extends from the bottom plate portion 32 to the top plate portion 22 in a manner that surrounds the ignition device 4. The inner cylinder member 5 is formed into a cylindrical shape with both ends open. In the combustion chamber 10, a ignition chamber 51 is formed between the inner cylinder member 5 and the ignition device 4. The ignition chamber 51 is a space for accommodating the first gas generator 110. The first gas generator 110 is burned by the operation of the igniter 41 to generate combustion gas, etc. In addition, a plurality of connecting holes 52 are formed in the inner cylinder member 5 so that its internal space (i.e., the ignition chamber 51) is connected to the external space. In the state before the ignition device 4 is operated, the connecting hole 52 is closed by a sealing tape (not shown).

[0065] [Filter]

[0066] The filter 6 is a cylindrical member formed of a metal material and extending in the vertical direction, and has a plurality of holes. Figure 2 As shown, the filter 6 is arranged in the combustion chamber 10 so as to surround the second gas generant 120, and the gas discharge hole 11 is located radially outside the filter 6. In other words, the filter 6 is arranged between the second gas generant 120 and the gas discharge hole 11 so as to surround the second gas generant 120. Of the two axial end faces of the filter 6, one end face (the upper end face indicated by reference numeral 61) abuts and is supported by the top plate portion 22 of the upper housing 2, and the other end face (the lower end face indicated by reference numeral 62) abuts and is supported by the bottom plate portion 32 of the lower housing 3.

[0067] The filter 6 has a plurality of holes formed therein, allowing the combustion gas from the second gas generant 120 disposed in the combustion chamber 10 to pass through the filter 6. The filter 6 functions as a coolant, removing heat from the combustion gas as it passes through the filter 6, thereby cooling the combustion gas. Furthermore, the filter 6 not only cools the combustion gas as described above, but also filters the combustion gas by capturing combustion residues contained therein.

[0068] [Gas generating agent]

[0069] The first gas generator 110 is a so-called transfer powder that burns when the ignition device 4 is operated, thereby igniting the second gas generator. As the first gas generator 110, in addition to using the well-known black powder, a gas generator with good ignition properties and a combustion temperature higher than that of the second gas generator 120 can also be used. The combustion temperature of the first gas generator 110 can be set within the range of 1700 to 3000°C. As such a first gas generator 110, for example, a well-known gas generator containing nitroguanidine (34% by weight) or strontium nitrate (56% by weight) can be used. In addition, the first gas generator 110 can be in various shapes, such as granular, pelletized, cylindrical, or disc-shaped.

[0070] A gas generant with a relatively low combustion temperature can be used for the second gas generant 120. The combustion temperature of the second gas generant 120 can be set within a range of 1000 to 1700°C. For example, a known gas generant containing guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), a binder, and additives can be used as the second gas generant 120. Furthermore, the second gas generant 120 can be in various shapes, such as granules, pellets, cylinders, and discs.

[0071] [Temperature rise suppression member]

[0072] The temperature rise suppression member 7 is a member that absorbs the heat of the housing 1 when the housing 1 is heated by the combustion of the gas generating agent, thereby suppressing further temperature rise of the housing 1. Figure 2 As shown, the temperature-rise suppression member 7 is provided to cover a portion of the outer surface S1 of the housing 1. In this embodiment, the temperature-rise suppression member 7 is provided only in contact with the outer surface S22 of the top plate portion 22 of the outer surface S1, which faces the airbag 200 in the airbag module assembly 1000. The outer surface S22 of the top plate portion 22 is covered by the film-like temperature-rise suppression member 7. The temperature-rise suppression member 7 of this embodiment contacts the outer surface S1 of the housing 1 (in this example, the outer surface S22) to facilitate heat transfer from the housing 1 to the temperature-rise suppression member 7. The temperature-rise suppression member 7 is in close contact with the outer surface S22 over the entire area of ​​the top plate portion 22, where the temperature-rise suppression member 7 is located in the housing 1. When the housing 1 heats up due to the combustion of the gas generant, the heat from the housing 1 is transferred to the temperature-rise suppression member 7 through heat conduction. It should be noted that the technology disclosed herein is not limited to the location of the housing where the temperature-rise suppression member is provided. The temperature-rise suppression member can be provided in contact with the outer surface of the housing, covering at least a portion of the outer surface of the housing. For example, the temperature-rise suppression member may be provided so as to be in contact with the entire outer surface of the housing.

[0073] The temperature-rise suppression member 7 includes a heat-absorbing agent exhibiting a heat-absorbing effect and a binder that exists together with the heat-absorbing agent to impart flexibility to the temperature-rise suppression member 7 , and is preferably formed by mixing these.

[0074] When the housing 1 heats up to a predetermined temperature due to combustion of the gas generant, the heat-absorbing agent absorbs the heat from the housing 1 by chemically or changing its state using the heat from the housing 1. The predetermined temperature is set to a temperature higher than the temperature of the housing 1 before the gas generator 100 is operated, but lower than the maximum temperature of the housing 1 assumed when the gas generant combusts without the temperature-rise suppression member 7 installed. The predetermined temperature is not particularly limited; for example, if the maximum temperature of the housing 1 heated by combustion of the gas generant without the temperature-rise suppression member 7 is 300°C, the predetermined temperature is set to less than 300°C. In other words, the heat-absorbing agent undergoes a chemical or state change accompanied by heat absorption at a temperature lower than the maximum temperature of the housing 1 assumed when the gas generant combusts without the temperature-rise suppression member 7 installed, thereby suppressing the temperature of the housing 1 from rising to the aforementioned maximum temperature. The chemical change of the heat-absorbing agent caused by the heat of the housing 1 here refers to a change into a different compound. Furthermore, the state change of the heat-absorbing agent caused by the heat of the housing 1 refers to a physical change in form. The type of chemical or state change caused by heat in the heat absorber is not particularly limited. Examples of chemical changes include thermal decomposition of a compound, and sublimation from a solid to a gas. Specifically, the heat absorber can absorb heat from the housing 1 by thermally decomposing it using the heat from the housing 1, or by sublimating from a solid to a gas using the heat from the housing 1. The heat absorber cools the housing 1 by removing the thermal energy required for these state or chemical changes from the housing 1.

[0075] A non-combustible heat absorber can be used. For example, as a compound that thermally decomposes at temperatures below 300°C, the heat absorber can be composed of at least one selected from the group consisting of fatty acid polycarbonate and magnesium carbonate. Furthermore, as a substance that exhibits heat absorption by sublimation, the heat absorber can be composed of at least one selected from the group consisting of p-dichlorobenzene, DL-camphor, naphthalene, fumaric acid, and terephthalic acid. The heat absorber can include a combination of the aforementioned compounds. However, the materials of the heat absorber disclosed herein are not limited to the aforementioned materials.

[0076] An adhesive is used together with a heat absorber to impart flexibility to the temperature rise suppression member 7. The adhesive can coexist with the heat absorber in the temperature rise suppression member 7, and there is no particular restriction on the configuration of the adhesive, but it is preferably mixed in the heat absorber. By using an adhesive to impart flexibility to the temperature rise suppression member 7, the adhesion of the temperature rise suppression member 7 to the housing 1 is improved, and the temperature rise suppression member 7 is difficult to peel off from the housing 1. In this sense, the heat absorber and the adhesive do not need to be mixed in the temperature rise suppression member 7. For example, the adhesive may not be mixed with the heat absorber but may be configured separately so that the adhesive is interposed in a layer between the housing and the heat absorber. However, from the viewpoint of improving the flexibility of the temperature rise suppression member 7, it is more preferable to mix the adhesive with the heat absorber and integrate them. In addition, by imparting flexibility to the temperature rise suppression member 7, it is possible to prevent the temperature rise suppression member 7 attached to the housing 1 from being damaged (generating cracks, etc.) due to deformation of the housing 1 or impact from the outside.

[0077] The adhesive used is preferably one that does not generate unwanted gases (such as carbon monoxide or nitrogen oxides) even when decomposed by heat during operation of the gas generator 100. In this regard, the adhesive is preferably composed of a compound containing, for example, a hydroxyl or carbonyl group as a functional group in the molecule, and more preferably mixed with a heat absorbent. Furthermore, by using a compound containing these functional groups as the adhesive, the flexibility of the temperature rise suppression member 7 is appropriately improved. Furthermore, even if the adhesive is heated by heat transfer from the housing 1 and generates gas, the gas can be rendered harmless.

[0078] The adhesive can be composed, for example, of at least one compound selected from the group consisting of butadiene rubber, silicone rubber, polyvinyl alcohol, ethylene vinyl alcohol, styrene-butadiene rubber, natural rubber, chloroprene rubber, isoprene rubber, acrylic rubber, alkyl acetalized polyvinyl alcohol, and polycarboxylic acid copolymers. The adhesive can also include a combination of the aforementioned compounds. For example, by using an alkyl acetalized polyvinyl alcohol or polycarboxylic acid copolymer as an adhesive mixed with an endothermic agent, even if the temperature rise suppression member 7 applied to the housing 1 is bent, cracks are unlikely to form, and the temperature rise suppression member 7 is difficult to peel from the housing 1. However, the adhesive material disclosed herein is not limited to the aforementioned materials.

[0079] Here, it is preferable that the content ratio of the heat-absorbing agent in the temperature-rise suppression member 7 be set to 70% to 95%, and the content ratio of the adhesive in the temperature-rise suppression member 7 be set to 5% to 30%. This allows the heat-absorbing effect of the heat-absorbing agent to suppress the temperature rise of the housing 1, while also providing appropriate flexibility to the temperature-rise suppression member 7. For example, if the temperature-rise suppression member 7 is a mixture consisting solely of a heat-absorbing agent and an adhesive, the ratio of the heat-absorbing agent to the adhesive can be selected from a range of 7:3 to 95:5. However, the content ratios of the heat-absorbing agent and the adhesive in the temperature-rise suppression member of the present disclosure are not limited to the above ranges. Furthermore, the temperature-rise suppression member may also be configured to include materials other than the heat-absorbing agent or adhesive described above.

[0080] The temperature-rise suppression member 7 can be provided on the outer surface S1 of the housing 1 as a coating film by, for example, applying the temperature-rise suppression member 7 on the outer surface S1 of the housing 1 while being dissolved in a solvent and drying the coating film.

[0081] [action]

[0082] Below, refer to Figure 1 and Figure 2 , the operation of the gas generator 100 and the airbag module assembly 1000 of embodiment 1 will be described. When the vehicle's sensor (not shown) senses an impact, an ignition current is supplied to a pair of energized pins 412, 412, and the igniter 41 operates. Then, the detonator contained in the cup body 411 of the igniter 41 burns, and the flame, high-temperature gas, etc., which are the combustion products, are discharged to the outside of the cup body 411. As a result, the first gas generator 110 contained in the ignition chamber 51 burns, generating combustion gas. The combustion gas of the first gas generator 110 breaks through the sealing tape that closes the connecting hole 52 and is discharged from the connecting hole 52 to the outside of the ignition chamber 51. Then, the combustion gas of the first gas generator 110 contacts the second gas generator 120, and the second gas generator 120 is ignited. The second gas generator 120 burns, thereby generating high-temperature / high-pressure combustion gas in the combustion chamber 10. This combustion gas passes through the filter 6, whereby the combustion gas is cooled and the combustion residue is captured. After being cooled and filtered by the filter 6, the combustion gas of the second gas generant 120 passes through the gap 13, breaks through the sealing tape that seals the gas discharge hole 11, and is discharged from the gas discharge hole 11 to the exterior of the gas generator 100. After being discharged to the exterior of the gas generator 100, the combustion gas of the second gas generant 120 flows into the airbag 200 within the module case 300. When the airbag 200 is inflated by the supplied gas, the inflation pressure causes the front portion 402 of the module case 300 to rupture, causing the airbag 200 to fly out of the module case 300 and deploy in front of the occupant. This creates a buffer between the occupant and the rigid structure, protecting the occupant from impact.

[0083] [Suppressing housing temperature rise]

[0084] When the gas generator 100 is operating, the heat generated by the combustion of the gas generating agent is transferred to the housing 1 and, through heat conduction, is transferred to the temperature rise suppression member 7 in contact with the housing 1. Therefore, as the housing 1 heats up, the temperature of the temperature rise suppression member 7 also rises. When the temperature rise suppression member 7 reaches a predetermined temperature, the heat absorber contained in the temperature rise suppression member 7 begins to undergo a state change or chemical change. At this time, the heat absorber removes thermal energy from the housing 1 and uses this thermal energy for chemical or state changes. As a result, the housing 1 is cooled by the heat absorption effect of the heat absorber, suppressing the temperature rise of the housing 1. Since the housing 1 absorbs heat from the contact portion with the temperature rise suppression member 7, the temperature rise of the top plate portion 22 in contact with the temperature rise suppression member 7 is suppressed.

[0085] Here, if Figure 1 As shown, in the airbag module assembly 1000, the gas generator 100 is arranged in such a manner that the top plate portion 22 is opposite to the folded airbag 200. Therefore, the airbag 200 that is deflated after deployment is in a state that is easy to contact with the top plate portion 22 of the housing 1. If the top plate portion 22 of the housing 1 reaches an excessively high temperature after the gas generator 100 is operated, the airbag 200 that is deflated after deployment may contact with the top plate portion 22 of the housing 1, and the airbag 200 may melt, generating undesirable gas or odor. In addition, as Figure 2 As shown, in the gas generator 100 of this embodiment, the upper end surface 61 of the metal filter 6, which is covered with high-temperature combustion residue, abuts the top plate 22 of the housing 1. Furthermore, in the gas generator 100 of this embodiment, the upper end of the metal inner cylindrical member 5, which is filled with the first gas generant 110, abuts the top plate 22 of the housing 1. Therefore, a large amount of heat is conducted to the top plate 22 via the filter 6 and the inner cylindrical member 5. In particular, most of this heat comes from the combustion residue generated by the first and second gas generants 110 and 120, which adheres to the inner surface of the housing 1 or the filter 6, causing the housing 1 to heat up. Specifically, since the temperature of the housing 1 gradually rises after the gas generator 100 operates, the temperature of the housing 1 reaches its maximum after the airbag 200 has performed its function (after the airbag 200 has deflated). Therefore, if the gas generator 100 without the temperature-rise suppressing member 7 is operated, the top plate 22 easily reaches a high temperature. If the deployed bag comes into contact with the top plate 22 in this state, the bag melts, causing odor or undesirable gas to be generated.

[0086] In contrast, in the gas generator 100 of this embodiment, the temperature-rise suppression member 7 is disposed in contact with the outer surface S22 of the top plate 22 of the housing 1. Therefore, as described above, the top plate 22 of the housing 1, where it contacts the temperature-rise suppression member 7, is prevented from heating up. Consequently, in the airbag module assembly 1000, the top plate 22 facing the airbag 200 is prevented from reaching excessively high temperatures. Consequently, the airbag 200, which contracts after deployment, is prevented from melting due to contact with the top plate 22 of the housing 1. This suppresses the generation of odors and undesirable gases. Furthermore, by suppressing melting of the airbag 200 after the gas generator 100 is activated, the airbag 200 is prevented from adhering to the housing 1 of the gas generator 100. As a result, the activated gas generator 100 is easily disposed of. Furthermore, since the temperature of the housing 1 is suppressed, the gas generator 100 prevents burns to passengers who come into contact with the housing 1.

[0087] For example, when using the airbag 200 made of polyamide, the airbag 200 melts at around 350°C. However, the gas generator 100 can prevent the airbag 200 from melting by suppressing the temperature of the housing 1 to, for example, 250°C or less by the temperature rise suppression member 7 after the gas generator 100 is operated.

[0088] Furthermore, by imparting flexibility to the temperature-rise suppression member 7 using an adhesive, the member's adhesion to the housing 1 is improved, making it less likely to peel from the housing 1. This prevents the member 7 from peeling due to vibrations experienced during vehicle travel or during transportation of the gas generator 100, or from peeling due to temperature differences in the housing 1 before and after the gas generator 100 is operated. Furthermore, even if the housing 1 deforms due to the pressure of the combustion gas, the member 7's flexibility allows it to follow the deformation, thus preventing damage to the member 7. Furthermore, imparting flexibility to the member 7 also prevents damage to the member 7 due to external impact. As a result, the temperature increase of the housing 1 after the gas generator 100 is operated can be effectively suppressed. Furthermore, by improving the adhesion of the member 7 to the housing 1, the number of members 7 can be reduced. Consequently, the gas generator 100 can be space-saving. In this regard, the temperature rise suppression member 7 may be configured such that the adhesive and the heat absorber are separated into layers and the adhesive side is in contact with the housing 1, or may be configured such that an adhesive layer is further formed thereon (on the heat absorber). However, in order to give the temperature rise suppression member 7 uniform softness as a whole, it is preferably configured on the outer surface S22 of the top plate portion 22 of the housing 1 in a state where the heat absorber and the adhesive are mixed.

[0089] [Function / Effect]

[0090] As described above, the gas generator 100 of Embodiment 1 includes: gas generators 110 and 120 that generate gas through combustion; a metal housing 1 that houses the gas generators; and an ignition device 4 that ignites the gas generators upon operation. The housing 1 is formed with a gas discharge hole 11 for discharging combustion gas generated by the combustion of the gas generators to the outside. Furthermore, the gas generator 100 includes a temperature rise suppression member 7, which is disposed in contact with the outer surface S1 of the housing 1, covering at least a portion (in this example, the outer surface S22) thereof. The temperature rise suppression member 7 is constructed to include a heat absorber and an adhesive. When the temperature of the housing 1 rises due to the combustion of the gas generators, the heat absorber undergoes a chemical change or a change in state due to the heat of the housing 1, thereby absorbing the heat from the housing 1. The adhesive is present together with the heat absorber to impart flexibility to the temperature rise suppression member 7, and is preferably used in a state where it is integrated with the heat absorber by being mixed with the heat absorber.

[0091] According to this gas generator 100, when the housing 1 rises due to the combustion of the gas generating agent, the heat absorbent contained in the temperature-rise suppression member 7 actively removes heat energy from the housing 1 due to a change in state or chemical change, thereby appropriately suppressing the temperature increase of the housing 1 after the gas generator 100 is activated. Furthermore, by imparting flexibility to the temperature-rise suppression member 7 using an adhesive, the temperature-rise suppression member 7 can be attached to the housing 1 with good adhesion. As a result, it is possible to suppress the temperature-rise suppression member 7 from peeling off from the housing 1 for a long period of time, thereby more effectively suppressing the temperature increase of the housing 1. According to this gas generator 100, after the gas generator 100 is activated, the thermal effects on the components arranged around the housing 1 (in this example, the airbag 200) can be reduced. This is suitable for cases where components (resin components) that are easily affected by heat are arranged around the housing 1.

[0092] Furthermore, in the gas generator 100 of this embodiment, the housing 1 includes a cylindrical peripheral wall portion 12 formed with a gas discharge hole 11, a top plate portion 22 that closes one end of the peripheral wall portion 12, and a bottom plate portion 32 that closes the other end of the peripheral wall portion 12. The gas discharge hole 11 is formed at a position in the axial direction of the housing 1 such that the distance d1 between the gas discharge hole 11 and the top plate portion 22 is shorter than the distance between the gas discharge hole 11 and the bottom plate portion 32. Furthermore, in the gas generator 100, a temperature rise suppression member 7 is provided on the outer surface S22 of the top plate portion 22 of the housing 1, closer to the gas discharge hole 11 than the bottom plate portion 32. This allows the heat absorbed by the temperature rise suppression member 7 to act on the top plate portion 22, effectively suppressing temperature increases in the top plate portion 22 of the housing 1. Consequently, the thermal effects on components (in this example, the airbag 200) disposed opposite the top plate portion 22 of the housing 1 can be further reduced. In this regard, the airbag module assembly 1000 of this embodiment includes a gas generator 100 and an airbag 200. The airbag 200 is arranged in a folded state and is inflated and deployed by gas discharged from the gas discharge hole 11. The gas generator 100 is arranged such that the top plate portion 22 of the housing 1 faces the folded airbag 200. Therefore, according to the gas generator 100 of this embodiment, the thermal effects on the airbag 200, which is the component arranged to face the top plate portion 22 of the housing 1, can be reduced.

[0093] It should be noted that the technology disclosed herein does not limit the location in the housing where the temperature rise suppression member is provided, but it is preferred that the temperature rise suppression member be provided at a location where the heat caused by the combustion of the gas generator is easily transferred, or, in the case where there are components around which the heat is to be avoided, the temperature rise suppression member be provided at a location close to the components. For example, it is preferred that the temperature rise suppression member be provided so as to contact the outer surface of a portion of the housing that abuts against a filter to which high-temperature combustion residue is attached (at least one of the first closed portion and the second closed portion), or the outer surface of a portion adjacent to a combustion chamber for combustion of the gas generator (i.e., a portion that demarcates the combustion chamber).

[0094] [Modification]

[0095] Hereinafter, a gas generator and an airbag module assembly according to a modified example of the first embodiment will be described. Figure 1 and Figure 2 The description will focus on the differences from the gas generator 100 described above, and detailed description of the same points as the gas generator 100 will be omitted.

[0096] [Variation 1]

[0097] Figure 3 This is a partially enlarged view of a gas generator 100A according to a first modification of the first embodiment. Figure 3, the portion where the temperature rise suppressing member 7 is provided in the housing 1A of the modification 1, that is, the vicinity of the top plate portion 22 is shown. Figure 3 As shown, the gas generator 100A of Modification 1 differs from the aforementioned gas generator 100 in that the outer surface S22 of the outer surface S1 of the housing 1A, which contacts the temperature rise suppression member 7, is formed with a concavo-convex shape. This concavo-convex shape is formed, for example, by roughening the surface of the housing 1. The outer surface S1 of the housing 1A may have the concavo-convex shape throughout its entire outer surface S22, or only a portion of it.

[0098] According to the gas generator 100A of Modification 1, by forming the outer surface S22 of the outer surface S1 of the housing 1A, which contacts the temperature-rise suppression member 7, into a concave-convex shape, the contact area between the temperature-rise suppression member 7 and the outer surface S22 can be increased compared to a case where the outer surface S22 is flat. This improves the efficiency of heat transfer from the housing 1 to the temperature-rise suppression member 7. As a result, heat absorption by the temperature-rise suppression member 7 is promoted, and the temperature increase of the housing 1 can be more effectively suppressed.

[0099] [Variation 2]

[0100] Figure 4 This is a cross-sectional view showing a state before operation of an airbag module assembly 1000B including a gas generator 100B according to a second modification of the first embodiment. Figure 5 : is a cross-sectional view showing a state of gas generator 100B before operation according to modification 2 of embodiment 1. Figure 4 and Figure 5 , a cross section along the central axis A1 of the housing 1 is shown.

[0101] like Figure 5 As shown, the inner cylinder member 5B of the second modification is formed into a bottomed cylinder with one end (upper end) closed and the other end (lower end) open, and is attached to the bottom plate portion 32 by welding the collar 42 of the ignition device 4 to its lower end.

[0102] Modification 2 illustrates a structure for suppressing temperature increases on the bottom plate portion 32 side of the housing 1. Specifically, in gas generator 100B of Modification 2, temperature-rise suppression member 7 is provided so as to contact only the outer surface S32 of the bottom plate portion 32 of the housing 1. The entire outer surface S32 of the bottom plate portion 32, excluding the mounting holes 32a, is covered by the film-like temperature-rise suppression member 7. More specifically, the temperature-rise suppression member 7 is in close contact with the outer surface S32 across the entire area of ​​the bottom plate portion 32, where the temperature-rise suppression member 7 is located in the housing 1.

[0103] In addition, the gas generator 100B of the second modification includes a label sheet 8. The label sheet 8 is a sheet-like member displaying predetermined information, and is attached to the temperature-rise suppression member 7 so that the temperature-rise suppression member 7 is sandwiched between the label sheet 8 and the housing 1. The label sheet 8 is attached to the temperature-rise suppression member 7 with one of its two surfaces (the mounting surface 8a) in contact with the temperature-rise suppression member 7. The other surface (the display surface 8b) of the label sheet 8 displays predetermined information.

[0104] The display surface 8b of the label sheet 8 displays predetermined information, such as information related to the gas generator 100B. Examples of information related to the gas generator 100B include operating instructions, manufacturer information, model number, and a management barcode. However, the information displayed on the label sheet of the present disclosure is not limited to the above.

[0105] The material of the label sheet 8 is not particularly limited, and for example, a heat-resistant resin material such as polyester film can be used. The label sheet 8 can be attached to the bottom plate portion 32, for example, by utilizing the adhesiveness of the temperature rise suppression member 7. In other words, the temperature rise suppression member 7 can be sandwiched between the housing 1 and the label sheet 8 as an adhesive (adhesive layer). It should be noted that an adhesive can also be applied to the mounting surface 8a to attach the label sheet 8 to the temperature rise suppression member 7. In addition, the method of displaying the specified information on the display surface 8b of the label sheet 8 is not particularly limited, and for example, the specified information can be recorded on the display surface 8b by printing or engraving.

[0106] like Figure 4 As shown, in airbag module assembly 1000B, bottom plate portion 32 of housing 1 is exposed outside module case 300. In gas generator 100B of Modification 2, label sheet 8 is attached to outer surface S32 of bottom plate portion 32 of housing 1 via temperature-rise suppression member 7, allowing for visibility from outside the module when assembled into airbag module assembly 1000B. However, the location for attaching label sheet 8 is not limited to bottom plate portion 32.

[0107] According to the gas generator 100B of Modification 2, a temperature-rise suppression member 7 is interposed between the label sheet 8 and the bottom plate 32 of the housing 1, thereby suppressing the temperature increase of the bottom plate 32 after the gas generator 100B is in operation. This suppresses the temperature increase of the bottom plate 32, to which the label sheet 8 is attached via the temperature-rise suppression member 7, thereby also suppressing the temperature increase of the label sheet 8 after the gas generator 100B is in operation. This prevents, for example, the label sheet 8 from discoloring, denaturing, or burning due to high temperatures after the gas generator 100B is in operation, thereby preventing the visibility of the displayed content on the label sheet 8 from being reduced. In other words, the thermal effects on the label sheet 8 after the gas generator 100B is in operation can be reduced.

[0108] <Implementation Method 2>

[0109] Hereinafter, the gas generator and the airbag module assembly of the second embodiment will be described. Figure 1 and Figure 2 The description will focus on the differences between gas generator 100 and the first embodiment, and detailed description of the same points as gas generator 100 will be omitted.

[0110] Figure 6 1 is a cross-sectional view showing a state before operation of an airbag module assembly 1000C including the gas generator 100C according to the first embodiment. Figure 6 , a cross section perpendicular to the central axis A1 of the housing 1C is shown. Figure 6 In FIG, the inner cylindrical member 5C, the filter 6, the gas generating agent, etc. of the gas generator 100C are omitted from illustration. Figure 7 1 is a cross-sectional view showing a state of the airbag gas generator 100C before operation according to the first embodiment. Figure 7 , a cross section along the central axis A1 of the housing 1C is shown.

[0111] like Figure 6 As shown, an airbag module assembly 1000C includes an inflator 100C, an airbag 200, and a module case 600 that accommodates them. As an example, the airbag module assembly 1000C is a front airbag device installed on the passenger seat of a vehicle (more specifically, the instrument panel above the passenger seat). However, the airbag module assembly 1000C can be used in both front and side airbag devices for the driver's seat.

[0112] The module case 600 is a housing that houses the gas generator 100C and the airbag 200. The module case 600 includes an airbag cover 700 and a retainer 800. The airbag cover 700 includes a quadrilateral frame-shaped sidewall portion 701 that forms the side surfaces of the module case 600, and a front portion 702 that closes one end of the sidewall portion 701 and forms the front surface of the module case 600. The airbag cover 700 is configured such that the front portion 702 forms, for example, a portion of the vehicle's instrument panel. The retainer 800 is fixed to a vehicle structure (not shown) and, by being locked to the sidewall portion 701 of the airbag cover 700, forms a housing space for the gas generator 100C and the airbag 200 together with the airbag cover 700. The gas generator 100C is positioned within the module case 600 with the peripheral wall portion 12 of the housing 1C facing the front portion 702. Furthermore, the airbag 200 is arranged in a folded state between the peripheral wall portion 12 of the gas generator 100 and the front portion 702 of the module box 600 .

[0113] The airbag module assembly 1000C is installed in the vehicle so that the front portion 702 of the airbag cover 700 faces the occupant protected by the airbag 200 (in this example, the passenger seat occupant). When the inflator 100C is activated, the front portion 702 ruptures due to the pressure generated by the expansion of the airbag 200. This causes the airbag 200 to fly out of the module case 600 and deploy in front of the occupant, thereby protecting the occupant from impact.

[0114] like Figure 7 As shown, a gas generator 100C according to Embodiment 2 is formed into an elongated cylindrical shape and includes an ignition device 4, an inner cylindrical member 5C, a filter 6, a first gas generant 110, a second gas generant 120, a metal housing 1C for housing these, a temperature rise suppression member 7 provided on an outer surface S1 of the housing 1C, and a partition member 9. The gas generator 100C of this embodiment is configured as a pyrotechnic gas generator using only a gas generant as a gas source, but may also be configured as a hybrid gas generator using a gas generant and pressurized gas as gas sources.

[0115] like Figure 7As shown, the housing 1C of Embodiment 2 is formed into a bottomed cylindrical shape with one end (upper end) closed and the other end (lower end) open. The housing 1C includes a cylindrical peripheral wall portion 12, a top plate portion 14 that closes one end (upper end) of the peripheral wall portion 12, and a fixing portion 15 that extends radially inward from the other end (lower end) of the peripheral wall portion 12. In the gas generator 100C of Embodiment 2, the ignition device 4 is fixed to the lower end of the peripheral wall portion 12 by riveting the fixing portion 15 while the ignition device 4 is fitted into the lower end of the peripheral wall portion 12. The inner cylindrical member 5C is formed into a cylindrical shape with both ends open. The inner cylindrical member 5C is attached to the housing 1C by fitting (pressing) the collar 42 of the ignition device 4 into the lower end while the upper end abuts the top plate portion 14 of the housing 1C. The inner cylindrical member 5C includes a first outer diameter portion 53 including its upper end and a second outer diameter portion 54 including its lower end. The outer diameter of the first outer diameter portion 53 is smaller than the outer diameter of the second outer diameter portion 54, and the first outer diameter portion 53 and the second outer diameter portion 54 are connected by a step portion 55 extending in the radial direction. In addition, a connecting hole 52 is formed in the first outer diameter portion 53. The upper end surface 61 of the filter 6 abuts and is supported by the top plate portion 14, and the lower end surface 62 abuts and is supported by the step portion 55. The partition member 9 is a member that divides the internal space of the inner cylinder member 5C in the axial direction. The internal space of the inner cylinder member 5C is divided by the partition member 9 into a first combustion chamber 56 surrounded by the second outer diameter portion 54 and a second combustion chamber 57 surrounded by the first outer diameter portion 53. A plurality of through holes 91 are formed in the partition member 9, and the first combustion chamber 56 and the second combustion chamber 57 can be connected. A first gas generating agent 110 is arranged in the first combustion chamber 56, and a second gas generating agent 120 is arranged in the second combustion chamber 57.

[0116] like Figure 6 As shown, in the airbag module assembly 1000C, the gas generator 100C is arranged in such a manner that the peripheral wall portion 12 of the housing 1C is opposite to the airbag 200 in the folded state. More specifically, a portion of the peripheral wall portion 12 in the circumferential direction is opposite to the airbag 200. Here, the portion of the peripheral wall portion 12 that is opposite to the airbag 200 in the airbag module assembly 1000C is referred to as the opposite portion 121. In the gas generator 100C of embodiment 2, the gas discharge hole 11 is formed only in the opposite portion 121 of the peripheral wall portion 12. However, the present disclosure is not limited to this. For example, in the case where the airbag module assembly 1000C is applied to a side airbag device, etc., the gas discharge hole 11 may also be formed on the entire circumference of the peripheral wall portion 12.

[0117] In addition, if Figure 6As shown, in gas generator 100C of Embodiment 2, temperature-rise suppression member 7 is disposed in contact only with outer surface S12 of facing portion 121, the portion of housing 1C that faces airbag 200. Temperature-rise suppression member 7 is disposed so as to cover the entire area of ​​facing portion 121, excluding gas discharge hole 11. More specifically, temperature-rise suppression member 7 is in close contact with outer surface S12 throughout facing portion 121, the portion of housing 1C where temperature-rise suppression member 7 is disposed.

[0118] In Embodiment 2, when the igniter 41 is activated, the combustion products of the initiator are discharged into the first combustion chamber 56. The first gas generant 110 contained in the first combustion chamber 56 combusts, generating combustion gas. The combustion gas of the first gas generant 110 passes through the through-hole 91 of the partition member 9 and is discharged into the second combustion chamber 57. The combustion gas of the first gas generant 110 then contacts the second gas generant 120, igniting the second gas generant 120. The combustion of the second gas generant 120 generates high-temperature and high-pressure combustion gas in the second combustion chamber 57. This combustion gas passes through the communication hole 52 and the filter 6, where it is cooled and filtered. It then passes through the gap 13 and is discharged from the gas discharge hole 11 to the exterior of the gas generator 100C. After being discharged to the exterior of the gas generator 100C, the combustion gas of the second gas generant 120 flows into the airbag 200 within the module case 600. When the airbag 200 is inflated by the supplied gas, the inflation pressure causes the front portion 702 of the airbag cover 700 to rupture, causing the airbag 200 to fly out of the module box 600 and deploy in front of the occupant. This creates a buffer between the occupant and the hard structure, protecting the occupant from impact.

[0119] In the airbag module assembly 1000C of the second embodiment, the gas generator 100C is arranged so that the opposing portion 121 of the peripheral wall portion 12 faces the folded airbag 200. Therefore, the airbag 200, after deployment and deflation, is in a state where it is easily in contact with the opposing portion 121 of the housing 1C. In contrast, in the gas generator 100C of this embodiment, the temperature rise suppression member 7 is arranged so as to contact the outer surface S12 of the opposing portion 121 of the housing 1C. Therefore, the housing 1C is prevented from heating up at the opposing portion 121, which is the contact point with the temperature rise suppression member 7. Thus, in the airbag module assembly 1000C, the opposing portion 121 facing the airbag 200 can be prevented from reaching excessively high temperatures. As a result, in this embodiment, the thermal effects on the airbag 200, which is the component arranged to face the opposing portion 121 of the housing 1C, can be reduced.

[0120] As described above, gas generator 100C of Embodiment 2 can reduce the thermal effects on components disposed around peripheral wall 12 of housing 1C by providing temperature-rise suppression member 7 on outer surface S12 of peripheral wall 12. It should be noted that temperature-rise suppression member 7 may be provided so as to contact the entire peripheral wall 12.

[0121] <Other>

[0122] While the embodiments of the technology disclosed herein have been described above, the various aspects disclosed in this specification may be combined with any other features disclosed in this specification.

[0123] Description of Reference Numerals

[0124] 1: Shell;

[0125] 4: Ignition device;

[0126] 7: Temperature rise suppression component;

[0127] 8: label piece;

[0128] 11: Gas discharge hole;

[0129] 12: peripheral wall;

[0130] 22: top plate portion (an example of the first closing portion);

[0131] 32: bottom plate (an example of the second closing portion);

[0132] 100: Gas generator

[0133] 110: a first gas generating agent (an example of a gas generating agent);

[0134] 120: a second gas generating agent (an example of a gas generating agent);

[0135] 200: airbag;

[0136] 1000: Airbag module assembly.

Claims

1. A gas generator comprising: Gas generating agent, which generates gas by combustion; a metal housing that contains the gas generating agent and is formed with a gas discharge hole for discharging the gas generated by combustion of the gas generating agent to the outside; an ignition device, which ignites the gas generating agent by operation; and a temperature-rise suppressing member provided in contact with the outer surface of the housing so as to cover at least a portion of the outer surface; The temperature rise suppression member includes: a heat absorber that absorbs the heat of the housing by chemically changing or changing its state due to the heat of the housing when the temperature of the housing rises due to combustion of the gas generating agent; and an adhesive, which exists together with the heat absorbent, so as to impart flexibility to the temperature rise suppression member.

2. The gas generator according to claim 1, wherein The adhesive is mixed with the heat absorbent.

3. The gas generator according to claim 1 or 2, wherein The heat absorbent includes at least one selected from the group consisting of fatty acid polycarbonate, magnesium carbonate, fumaric acid, and terephthalic acid.

4. The gas generator according to any one of claims 1 to 3, wherein The binder includes a compound having a hydroxyl group or a carbonyl group.

5. The gas generator according to any one of claims 1 to 4, wherein The content ratio of the heat-absorbing agent in the temperature-rise suppression member is 70% or more and 95% or less, The content ratio of the binder in the temperature-rise suppression member is 5% to 30%.

6. The gas generator according to any one of claims 1 to 5, wherein The housing comprises: a cylindrical peripheral wall portion, in which the gas discharge hole is formed; a first sealing portion, which seals one end of the peripheral wall portion; and a second sealing portion, which seals the other end of the peripheral wall portion; The gas discharge hole is formed at a position in the axial direction of the housing such that a distance between the gas discharge hole and the first sealing portion is shorter than a distance between the gas discharge hole and the second sealing portion. The temperature-rise suppression member is provided on the outer surface of the first sealing portion.

7. The gas generator according to any one of claims 1 to 6, wherein The housing has a cylindrical peripheral wall portion in which the gas discharge hole is formed. The temperature rise suppression member is provided on the outer surface of the peripheral wall portion.

8. The gas generator according to any one of claims 1 to 7, wherein A portion of the outer surface of the housing that contacts the temperature-rise suppression member is formed in a concavo-convex shape.

9. The gas generator according to any one of claims 1 to 8, wherein The gas generator further includes a label sheet displaying prescribed information. The label sheet is attached to the temperature-rise suppression member so that the temperature-rise suppression member is interposed between the label sheet and the housing.

10. An airbag module assembly, comprising: The gas generator according to claim 6; and an airbag configured in a folded state and inflated and deployed by the gas discharged from the gas discharge hole; The gas generator is arranged so that the first sealing portion faces the airbag in a folded state.

11. An airbag module assembly, comprising: The gas generator according to claim 7; and an airbag configured in a folded state and inflated and deployed by the gas discharged from the gas discharge hole; The gas generator is arranged so that the peripheral wall portion faces the airbag in a folded state. The temperature rise suppression member is provided on an outer surface of a portion of the peripheral wall portion that faces the airbag.

Images