Airbag device and method for deploying airbag device

Abstract

To provide a technique for improving reliability of an airbag device.SOLUTION: An airbag device includes: a gas generator which has a first gas generating agent for generating combustion gas by ignition and an ignition section for igniting the first gas generating agent; and an airbag which receives supply of the combustion gas from the gas generator and is deployed. The airbag has an inflow section which is connected to the gas generator and makes the combustion gas supplied from the gas generator flow into an internal space of the airbag, a bag-like section which is bag-like member demarcating the internal space into which the combustion gas flows from the inflow section as an external section, is made a folded state at the time before receiving the supply of the combustion gas and becomes a deployed state by receiving the supply of the combustion gas, and a second gas generating agent which is arranged at a prescribed position on an inside surface of the bag-like section and generates gas without accompanying combustion reaction utilizing heat energy of the combustion gas.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an airbag device and a method for deploying an airbag device. [Background technology]

[0002] In recent years, vehicles have been equipped with airbag devices that protect occupants by deploying an airbag in the event of a collision. Various types of airbag devices have been proposed for vehicles, including those that are installed on the steering wheel, on the side of a seat, near the window side of the roof, etc.

[0003] Patent Document 1 discloses an airbag device that rapidly generates gas in the event of an accident to inflate a confinement and protect occupants. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Pat. No. 3,552,770 Summary of the Invention [Problem to be solved by the invention]

[0005] In an airbag device, gas is supplied at high pressure into the airbag in order to rapidly deploy the airbag in the event of a vehicle collision. In particular, in a side airbag device that cushions the impact when an occupant collides with the vehicle inner surface in the event of a side collision, the distance between the occupant and the vehicle inner surface is close, so it is desirable to deploy the airbag more quickly than other airbag devices, and the pressure of the gas supplied tends to be high. In addition, the initial pressure inside the airbag needs to be increased in order to break the airbag module. Note that the airbag device is designed so that even if the gas pressure supplied to the airbag is high, the occupant will not be affected when the airbag is deployed as long as the occupant is wearing a seat belt and sitting in the correct position. However, if the occupant does not sit in the correct position and leans against the airbag device or places an object on the part of the airbag device where the airbag device is deployed, and the airbag device is activated in an inappropriate state, it is possible that the pressure at the time of deployment will be transmitted to the occupant leaning against the airbag device, or the object placed on the deployment part will be thrown off and hit the occupant. In such a case, if the gas pressure supplied to the airbag is high, the impact on the occupant may be increased.

[0006] The technology of the present disclosure has been made in consideration of the above-mentioned circumstances, and has an object to provide a technology for improving the reliability of an airbag device. [Means for solving the problem]

[0007] In order to solve the above problems, the airbag device of the present disclosure comprises: a gas generator including a first gas generating agent that generates a combustion gas by ignition and an ignition unit that ignites the first gas generating agent; an airbag that is deployed by receiving the combustion gas from the gas generator, The airbag, an inlet portion connected to the gas generator and allowing the combustion gas supplied from the gas generator to flow into an internal space of the airbag; a bag-shaped member that separates an internal space into which the combustion gas flows from the inflow portion from an outside, the bag-shaped portion being in a folded state before receiving the supply of the combustion gas and being in an unfolded state when receiving the supply of the combustion gas; and a second gas generating agent that is disposed at a predetermined position on the inner surface of the bag-shaped portion and generates gas without a combustion reaction by utilizing the thermal energy of the combustion gas.

[0008] In the airbag device, a discharge hole of the combustion gas in the gas generator is disposed facing into the internal space, The second gas generating agent may be disposed in the bag-shaped portion in the folded state so as to face the discharge hole.

[0009] In the airbag device, a discharge hole of the combustion gas in the gas generator is disposed facing into the internal space, The second gas generating agent may be arranged on the inner surface of the bag-shaped portion at a position that is spaced away from the discharge hole in the deployment direction when the bag-shaped portion deploys from the folded state due to the inflow of the combustion gas.

[0010] In the airbag device, the gas generator includes a housing having a gas exhaust hole for exhausting the combustion gas, A deflector that deflects the flow of the combustion gas in the direction of deployment of the bag-shaped portion may be disposed around the gas discharge hole, and the second gas generating agent may be disposed in a portion to which the combustion gas deflected by the deflector is directed.

[0011] The second gas generating agent may be a substance that generates gas by being decomposed, vaporized, or sublimated by the thermal energy of the combustion gas.

[0012] The combustion gas may be supplied at a timing that is a predetermined time earlier than the timing at which gas is to be generated from the second gas generating agent.

[0013] In the airbag device, when a period during which the combustion gas is supplied to the bag-shaped portion is defined as a first period, the second gas generating agent may generate gas for a second period that is longer than the first period.

[0014] The airbag device may further include a cover disposed to cover at least a portion of the second gas generating agent and to be consumed by the thermal energy of the combustion gas.

[0015] The airbag device is provided with second gas generating agents having different reaction temperatures when generating the gas at a plurality of locations, Among the second gas generating agents provided at the multiple locations, the second gas generating agent having a higher reaction temperature than the other second gas generating agents may be arranged upstream of the other second gas generating agents in the flow direction of the combustion gas supplied from the gas generator.

[0016] In order to solve the above problems, a method for deploying an airbag device according to the present disclosure includes: A step of igniting the first gas generating agent by a gas generator including a first gas generating agent and an ignition unit that ignites the first gas generating agent to generate a combustion gas; an inflow section connected to the gas generator and allowing the combustion gas supplied from the gas generator to flow into an internal space of the airbag, and a bag-shaped member separating the internal space into which the combustion gas flows from the inflow section from the outside, the bag-shaped section being in a folded state before receiving the supply of the combustion gas and being in an expanded state when receiving the supply of the combustion gas, and a second gas generating agent disposed at a predetermined position on an inner surface of the bag-shaped section, the airbag device including an airbag receiving a supply of the combustion gas generated by the ignition and starting to expand the bag-shaped section; generating gas from a second gas generating agent disposed in the bag-shaped portion by utilizing thermal energy of the combustion gas without involving a combustion reaction; Includes. Effect of the Invention

[0017] According to the present disclosure, a technique for improving the reliability of an airbag device can be provided. [Brief description of the drawings]

[0018] [Figure 1] 1 is a schematic configuration diagram of an airbag device according to a first embodiment. [Diagram 2] FIG. 2 is a front view showing a state before the airbag device attached to the steering wheel is activated. [Diagram 3] FIG. 2 is a front view showing a state in which an airbag device attached to a steering wheel is activated. [Figure 4] FIG. 1 is a side view showing a state in which an airbag device 1 attached to a steering wheel is activated. [Diagram 5] FIG. 2 is an exploded perspective view of the airbag device. [Figure 6] FIG. 2 is an external view of the gas generator. [Figure 7] FIG. 2 is a cross-sectional view of the gas generator in a depth direction. [Figure 8] FIG. 2 is a diagram showing an airbag in a deployed state. [Figure 9] 4A to 4C are diagrams illustrating a process of deploying an airbag of the airbag device. [Figure 10] 6 is a diagram showing the relationship between the supply timing of the combustion gas and non-combustion gas and the pressure inside the bag-shaped portion. FIG. [Figure 11] FIG. 13 is a diagram showing an airbag device according to a first modified example. [Figure 12] 13A and 13B are diagrams illustrating a configuration of an airbag according to a second modified example. [Figure 13] FIG. 13 is a diagram showing an airbag device according to a third modified example. [Figure 14] FIG. 6 is a diagram showing an airbag device according to a second embodiment. [Figure 15] FIG. 4 is a diagram showing a configuration of a deflector. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an airbag device according to an embodiment of the present disclosure will be described with reference to the drawings. Note that each configuration and their combination in the embodiment is merely an example, and addition, omission, substitution, and other modifications of the configuration are possible as appropriate within the scope of the gist of the present disclosure. The present disclosure is not limited by the embodiment, but is limited only by the claims.

[0020] First Embodiment FIG. 1 is a schematic diagram of an airbag device 1 according to this embodiment. The airbag device 1 is installed, for example, inside a vehicle, and deploys an airbag 20 to protect an occupant when the vehicle crashes. However, the airbag device 1 may be installed outside the vehicle (for example, around the hood) to protect a pedestrian. The airbag device 1 may also be installed on a bicycle, a motorcycle, an entertainment vehicle (such as a roller coaster or a go-kart), or on a driver or occupant thereof. Furthermore, the airbag device 1 may be installed on a pedestrian. FIG. 1 shows an example of a so-called driver's seat airbag device attached to a steering wheel 40 of a vehicle.

[0021] Fig. 2 is a front view showing the state of the airbag device 1 attached to the steering wheel 40 before activation, Fig. 3 is a front view showing the state of the airbag device 1 attached to the steering wheel 40 when activated, Fig. 4 is a side view showing the state of the airbag device 1 attached to the steering wheel 40 when activated, and Fig. 5 is an exploded perspective view of the airbag device 1. In Figs. 1 to 5, the up-down direction is shown as the Y direction, the left-right direction is shown as the X direction, and the front-rear direction is shown as the Z direction. These directions are shown as examples for the convenience of explanation, and the configuration of the airbag device 1 is not limited to these. For example, the direction in which the airbag device 1 is arranged is not limited to the direction shown in the drawings. The same applies to the subsequent drawings.

[0022] The steering wheel 40 includes a ring-shaped steering wheel 42 that is gripped by the occupant (driver) when steering and rotated in the steering direction, a boss portion 43 located at the center of rotation, and spokes 44 that connect the boss portion 43 to the steering wheel 42. The boss portion 43 is attached to the occupant side end of a rotation center shaft (steering column) 45 that is connected to the steering mechanism of the vehicle, and transmits the operation of the steering wheel 42 by the driver to the rotation center shaft 45.

[0023] The airbag device 1 is attached to the driver's side of the boss portion 43. That is, the airbag device 1 is disposed between the steering wheel 40 and the driver, at the rotation center of the steering wheel 40. The airbag device 1 includes a gas generator 10 that generates gas when activated, an airbag 20 that deploys by receiving the gas, and an outer shell case 30.

[0024] The outer shell case 30 includes a retaining base 31 that retains the gas generator 10 and the airbag 20, and a cover member 32 that is attached to the driver's side of the retaining base 31. The retaining base 31 has a base plate portion 31A that is formed in the same shape as the boss portion 43 when viewed from the front, and a circular recess 31B into which the gas generator 10 is fitted is provided approximately in the center of the base plate portion 31A. The gas generator 10 is fitted into the recess 31B and fixed to the base plate portion 31A, and an inlet portion of the airbag 20 that deploys due to an inflow of gas from the gas generator 10 is fixed to the base plate portion 31A, whereby the retaining base 31 retains the gas generator 10 and the airbag 20.

[0025] The cover member 32 is attached to the holding base 31 so as to cover the airbag 20 held by the holding base 31. In other words, by being attached to the holding base 31, the cover member 32 forms an accommodation space 32A inside the outer shell case 30 formed by the holding base 31 and the cover member 32, and accommodates the gas generator 10 and the airbag 20 in this accommodation space. The cover member 32 is made of a synthetic resin or the like, and is provided at a predetermined position with a cleavage line (not shown) that is formed to be weaker than other portions.

[0026] <Gas generator> FIG. 6 is an external view of the gas generator 10, where (A) shows a front view of the gas generator 10, (B) shows a side view of the gas generator 10, and (C) shows a rear view of the gas generator 10. FIG. 7 is a vertical cross-sectional view along the depth direction of the gas generator 10. The gas generator 10 includes a housing 11, an igniter 14, a resin holding portion 15, a filter 16, a cup-shaped cover body 17, a transfer charge 18, a gas generating agent 19, and the like. The gas generator 10 is configured to combust the gas generating agent (first gas generating agent) 19 by activating the igniter 14, and to discharge the combustion gas, which is a combustion product, from a gas discharge hole 111 formed in the housing 11. Each component of the gas generator 10 will be described below.

[0027] The housing 11 is a metallic outer shell container that houses each of the components that make up the gas generator 10, and is configured to include a front shell 112 and a rear shell 113. The front shell 112 and the rear shell 113 are each formed in a substantially cylindrical shape with a bottom, and are joined together with their open ends facing each other to form the housing 11 as a short cylindrical outer shell container with both ends in the direction of the central axis C1 closed. The front shell 112 and the rear shell 113 can be formed, for example, by pressing a stainless steel plate.

[0028] Arranged inside the housing 11 are an igniter 14, a filter 16, a cup-shaped cover body 17, a transfer charge 18, a gas generating agent 19, and the like. Also, a combustion chamber 160 is formed inside the housing 11, and the gas generating agent 19 is accommodated in the combustion chamber 160. Here, in the direction along the central axis C1 of the housing 11, the front shell 112 side (i.e., the right side in FIG. 7) is the front side (front surface side) of the gas generator 10, and the rear shell 113 side (i.e. 7) is defined as the rear side of the gas generator 10.

[0029] The front shell 112 has a cylindrical front peripheral wall portion 121 and a front wall portion 122 that closes the front end of the front peripheral wall portion 121. The front wall portion 122 of the front shell 112 has a generally circular shape in a plan view, and the rear end of the front peripheral wall portion 121 is formed as an open end. In addition, a joint portion 123 that extends radially outwardly in a brim-like shape is provided at the rear end of the front peripheral wall portion 121 of the front shell 112. In addition, the rear shell 113 has a cylindrical rear peripheral wall portion 131 and a rear wall portion 132 that closes the lower end of the rear peripheral wall portion 131. In the rear shell 113, the rear wall portion 132 has a generally circular shape in a plan view, and the front end of the rear peripheral wall portion 131 is formed as an open end. In addition, a joint portion 133 that extends radially outwardly in a brim-like shape is provided continuously to the front end of the rear peripheral wall portion 131. Further, a mounting hole 13A for mounting the igniter 14 to the rear wall portion 132 is formed in the center of the rear wall portion 132 of the rear shell 113.

[0030] The joint portion 123 of the front shell 112 and the joint portion 133 of the rear shell 113 are overlapped with each other and joined by laser welding or the like to form the housing 11. In addition, the front peripheral wall portion 121 of the front shell 112 has a plurality of gas exhaust holes 111 formed in a row along the circumferential direction, which communicate between the internal space of the housing 11 and the external space.

[0031] The igniter 14 is fixed to a mounting hole 13A formed in a rear wall portion 132 of the rear shell 113 via a resin holder 15. The igniter 14 is an electric igniter having an ignition portion 141 in which an ignition charge is accommodated inside a metal cup body, a pair of conductive pins 142, 142, and the like. An ignition current for igniting the ignition charge accommodated in the cup body is supplied to the pair of conductive pins 142, 142. The base ends of the pair of conductive pins 142, 142 are inserted into the cup body while being held in an electrically insulated state by the resin holder 15. A bridge wire (resistance element) is provided inside the cup body so as to connect the base ends of the pair of conductive pins 142, 142 to each other. The bridge wire may be, for example, a nichrome wire. The ignition charge may be ZPP (zirconium potassium perchlorate). ZWPP (zirconium tungsten potassium perchlorate), THPP (titanium hydride potassium perchlorate), lead tricinate, etc. may be used. The ignition charge is contained inside the cup body in contact with the bridge wire.

[0032] When the igniter 14 is operated, the bridge wire is heated by an ignition current supplied to the pair of conductive pins 142, 142. As a result, the ignition charge accommodated inside the cup body of the igniter 14 is ignited and burned, and combustion products (for example, a flame) are generated. Then, the internal pressure of the cup body increases with the combustion of the ignition charge, and the cup body is cleaved, and the combustion products are released from the cleaved part of the cup body. In addition, a part of the pair of conductive pins 142, 142 of the igniter 14 is arranged so as to be exposed to a connector insertion space S1 formed on the outside of the housing 11 through the mounting hole 13A. The connector insertion space S1 is a space for inserting an external connector, and is formed by a part of the resin holding part 15. When the airbag device 1 is attached to the boss part of the steering wheel 40, an external connector (not shown) connected to the control unit 50 on the vehicle side is inserted into this connector insertion space S1, and the igniter 14 and the control unit 50 are electrically connected to each other. When the control unit 50 detects a vehicle collision and activates the airbag device 1, an ignition current is supplied from the control unit to the conductive pins 142, 142 via the external connector, whereby the igniter 14 is activated.

[0033] The resin retaining portion 15 is composed of a cylindrical base portion 151 that fixes the igniter 14 to the rear wall portion 132 of the rear shell 113, a cylindrical inner tube wall portion 152 that extends upward from the base portion 151 toward the front wall portion 122, and the like.

[0034] The inner cylinder wall portion 152 stands forward from the front surface of the base portion 151, and a transfer charge chamber 158 that accommodates the transfer charge 18 is formed inside the inner cylinder wall portion 152. The inner cylinder wall portion 152 is disposed so as to surround the periphery of the ignition portion 141 of the igniter 14. Therefore, the transfer charge chamber 158 formed inside the inner cylinder wall portion 152 is formed so as to face the ignition portion 141 of the igniter 14. When the gas generator 10 is manufactured, the transfer charge 18 can be filled into the transfer charge chamber 158 from the front end opening 153 of the inner cylinder wall portion 152. Then, the cup-shaped cover body 17 is inserted from the open end side of the inner cylinder wall portion 152, so that the transfer charge 18 is sealed in the transfer charge chamber 158. The inner cylinder wall portion 152 and the cup-shaped cover body 17 are made of resin, and can easily melt or burst when the transfer charge 18 in the transfer charge chamber 158 burns.

[0035] The filter 16 has, for example, a cylindrical shape and is arranged concentrically with the housing 11. The filter 16 can be formed, for example, by overlapping flat-woven stainless steel wire mesh in the radial direction and compressing it in the radial and axial directions. A cup-shaped cover body 17 attached to an inner cylindrical wall portion 152 is arranged inside the housing 11 at a distance from the filter 16, and a combustion chamber 160 for accommodating the gas generating agent 19 is formed by an annular space formed between an inner peripheral surface 161 of the filter 16 and the cup-shaped cover body 17. The combustion temperature of the gas generating agent 19 can be set in the range of, for example, 1000 to 1700°C. As such a gas generating agent 19, for example, a known agent containing guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), binders, and additives can be used. In addition, the gas generating agent 19 can be in various shapes, such as granular, pellet, cylindrical, and disk shapes.

[0036] 7, the filter 16 has its front end face and rear end face in contact with the inner wall surfaces of the front wall portion 122 of the front shell 112 and the rear wall portion 132 of the rear shell 113, respectively, and is assembled inside the housing 11 in an axially compressed state. The filter 16 has a function of filtering the combustion gas by collecting combustion residue contained in the combustion gas.

[0037] <Airbag> The airbag 20 is housed in a folded state in an outer shell case 30. When the airbag 20 receives gas from the gas generator 10, it inflates, rupturing the cover member 32 of the outer shell case 30 and deploying to the front side of the airbag device 1.

[0038] FIG. 8 is a diagram showing the airbag 20 in a deployed state, where (A) shows the front of the airbag 20, (B) shows a side of the airbag 20, and (C) shows the rear of the airbag 20. The airbag 20 has an inflow section 21 that receives a supply of combustion gas, and a bag-shaped section 23 that separates an internal space 22 into which the combustion gas flows from the inflow section 21 from the outside. The bag-shaped section 23 is formed into a bag shape by joining the outer peripheries of a front sheet 231 and a rear sheet 232, both of which have a circular outer shape. The front sheet 231 and the rear sheet 232 are formed of a flexible material so as to be foldable. For example, the front sheet 231 and the rear sheet 232 may be sheets of synthetic resin such as polyamide, nylon, or polyester, woven fabric, or woven fabric coated with synthetic resin.

[0039] The bag-shaped portion 23 is formed in a bag shape, and inflates when gas is supplied to the internal space 22 to function as an air cushion in order to restrict the gas from entering or exiting through any place other than a predetermined inlet or outlet. The inflow portion 21 is one of the gas inflow and outlet ports in the airbag 20. The inflow portion 21 is provided in the center of the rear sheet 232 as shown in FIG. 8(C), and has an opening 211 into which the front end portion of the gas generator 10 that supplies combustion gas is inserted. The bag-shaped portion 23 may have a vent hole as a gas inflow and outflow port for discharging excess gas.

[0040] As shown in FIG. 1, the airbag 20 is attached to the retaining base 31 of the outer shell case 30 by fixing the inlet portion 21 to the retaining base 31 by the retainer 24. Reference numeral 24 denotes an annular metal plate, which comes into contact with the inflow portion 21 from the inside of the bag-shaped portion 23 and is fastened to the holding base 31 with screws or the like in a state in which the inflow portion 21 is sandwiched between the bag-shaped portion 23 and the holding base 31. During this attachment, the bag-shaped portion 23 is folded as shown in Fig. 1, and the cover member 32 is attached to the holding base 31 so as to cover the bag-shaped portion 23. That is, in the initial state before the airbag device 1 is activated, the airbag 20 is housed in the outer shell case 30 in a folded state.

[0041] In addition, in the airbag 20, a second gas generating agent 233 that generates gas without a combustion reaction by utilizing the thermal energy of the combustion gas when the combustion gas is supplied from the gas generator 10 is disposed at a predetermined position on the inner surface of the bag-shaped portion 23. The second gas generating agent 233 is, for example, a substance that is solid at room temperature and sublimes into gas by the heat of the combustion gas (hereinafter also referred to as a sublimation substance). Examples of the sublimation substance include naphthalene (sublimation point: 209°C), tetrahydrofuran (sublimation point: 209°C), and tetrahydrofuran (sublimation point: 209°C). Examples of the sublimable substance include phthalic acid (sublimation point: 333°C) and biphenyl-4,4'-diol (sublimation point: <300°C). In addition, in the case of a sublimable substance, for example, the sublimation point is the reaction temperature (gas generation temperature). In addition, the second gas generating agent 233 may be, for example, a substance that is solid or liquid at room temperature and vaporizes to become gas by the heat of the combustion gas (hereinafter, also referred to as a vaporized substance).

[0042] Furthermore, the second gas generating agent 233 may be a substance that is solid or liquid at room temperature and decomposes due to the heat of the combustion gas, with at least a portion of the substance turning into gas (hereinafter also referred to as a pyrolyzed substance). Examples of pyrolyzed substances include sodium hydrogen carbonate and aliphatic polycarbonate (APC). In the case of sodium hydrogen carbonate, it decomposes at a reaction temperature (gas generating temperature) of around 270°C, generating CO 2 and H 2 In the case of aliphatic polycarbonate, it decomposes at around 230℃ and produces H 2 0 and CO 2 is generated as a gas component.

[0043] In this embodiment, the second gas generating agent 233 is arranged in a position facing the gas discharge hole 111 of the gas generator 10 in the bag-shaped portion 23 in the folded state, as shown in FIG.

[0044] <Control device> The control unit 50 detects the state of the vehicle or the state around the vehicle using the sensor 60, and based on the detection result, determines whether or not to activate the airbag device 1. If the airbag device 1 is to be activated, an ignition current is supplied to the airbag device 1.

[0045] The sensor 60 is, for example, an impact sensor for detecting a vehicle collision. The sensor 60 is not limited to a sensor for detecting an impact, but may be a sensor for detecting information about the surroundings of the vehicle in order to predict a collision with the vehicle. For example, the sensor 60 may include sensing means such as an acceleration sensor, a gyro sensor (angular velocity sensor), a positioning device, a camera, a radar, a LIDAR (Light Detection and Ranging, Laser Imaging Detection and Ranging), or a three-dimensional scanner. As a positioning device, for example, a GPS (Global Positioning System) or the like may be used. Satellite positioning systems include radar and LIDAR, which can measure the distance to objects around the vehicle and the speed at which those objects are moving.

[0046] The control unit 50 acquires the detection result by the sensor 60, and when the detection result satisfies a predetermined condition, it supplies an ignition current as described later to activate the airbag device 1.

[0047] <Deployment method> 9 is an explanatory diagram of the process of deploying the airbag 20 of the airbag device 1. When the power is supplied, for example, by turning on the ignition power of the vehicle, the control unit 50 acquires the detection result of the sensor 60 (step S10) and determines whether or not to deploy the airbag device 1 (step S20). Here, if the detection result of the sensor 60 is equal to or greater than a predetermined value or if the surrounding When the detection result satisfies a predetermined condition, such as when a collision is predicted based on the moving direction of an object (another vehicle, etc.) and the moving direction of the vehicle itself, it is determined that the airbag device 1 should be activated (step S20, Yes), and when the predetermined condition is not satisfied, it is determined that the airbag device 1 should not be activated (step S20, No).

[0048] When it is determined that the airbag device 1 is to be activated, the control unit 50 supplies an ignition current to the conductive pins 142, 142 of the igniter 14 of the gas generator 10 (step S30). Then, the ignition charge housed in the cup body of the ignition unit 141 of the igniter 14 burns, and the cup body is cleaved, and the transfer charge 18 is ignited and burned by the flame, high-temperature gas, etc. discharged from the ignition unit 141. The temperature and internal pressure in the transfer chamber 158 rise rapidly as the transfer charge 18 burns, and the inner cylinder wall portion 152 and the cup-shaped cover body 17 melt or explode due to the energy, and the combustion products (flame and high-temperature gas) are discharged from the transfer chamber 158 to the combustion chamber 160. Then, the combustion products come into contact with the gas generating agent 19 housed in the combustion chamber 160, and the gas generating agent 19 is ignited (step S40).

[0049] The high-temperature, high-pressure combustion gas generated by the combustion of the gas generating agent 19 in the combustion chamber 160 passes through the filter 16 and is discharged from the gas discharge hole 111 to the outside of the housing 11. That is, the combustion gas is supplied from the gas generator 10 into the bag-shaped portion 23 of the airbag 20 (step S50).

[0050] When the combustion gas is supplied to the internal space 22, the bag-shaped portion 23 inflates and starts to deploy (step S60). Then, the second gas generating agent 233 arranged on the inner surface of the bag-shaped portion 23 uses the thermal energy of the combustion gas to generate gas (non-combustion gas) without a combustion reaction (step S70). As a result, the combustion gas from the gas generator 10 and the gas from the second gas generating agent 233 (hereinafter also referred to as non-combustion gas) deploy the airbag 20, which functions as a cushion to protect the occupant.

[0051] Thus, in this embodiment, after the combustion gas is supplied from the gas generator 10 (step S50), the second gas generating agent 233 generates non-combustion gas by utilizing the thermal energy of the combustion gas (step S70). That is, the combustion gas is supplied at a timing that is a predetermined time earlier than the timing at which the non-combustion gas should be generated from the second gas generating agent 233. This difference in timing can be adjusted, for example, by changing the position at which the second gas generating agent 233 is arranged (for example, the distance from the gas discharge hole 111) or the amount of the second gas generating agent 233 arranged at each position. In addition, the gas generation timing may be adjusted by selecting a substance to be adopted as the second gas generating agent 233 according to the temperature at which the non-combustion gas is generated, for example, by adopting a substance having a low temperature at which the non-combustion gas is generated as the second gas generating agent 233 to advance the gas generation timing, or by adopting a substance having a high temperature at which the non-combustion gas is generated as the second gas generating agent 233 to delay the gas generation timing.

[0052] Also, the timing from the start to the end of the supply of non-combustion gas by the second gas generating agent 233, that is, the supply period of non-combustion gas, may be adjusted. For example, by adopting as the second gas generating agent 233 a substance having a fast reaction rate when generating non-combustion gas by heat, the supply period of non-combustion gas can be shortened, and by adopting as the second gas generating agent 233 a substance having a slow reaction rate when generating non-combustion gas by heat, the supply period of non-combustion gas can be set long. Also, by providing the second gas generating agent 233 thinly and widely, the supply period of non-combustion gas can be shortened, and by providing the second gas generating agent 233 thickly and narrowly, the supply period of non-combustion gas can be set long. And, by adjusting this supply timing and supply period, when deploying the airbag 20, the pressure at the beginning of deployment, the timing to complete deployment, the period during which a required pressure is maintained, and the like can be adjusted, and the EA (energy absorption) characteristics can be set appropriately.

[0053] FIG. 10 is a diagram showing the relationship between the timing of supplying the combustion gas and non-combustion gas and the pressure inside the bag-shaped portion 23. In FIG. 10, the horizontal axis indicates the elapsed time from the start of the operation, the vertical axis indicates the pressure, and the solid line SA indicates the pressure inside the bag-shaped portion 23. When the ignition current is supplied to the igniter 14 and the operation of the airbag device 1 is started (T0), the combustion gas is immediately supplied from the gas generator 10 by the combustion of the first gas generating agent. The supply start timing of this combustion gas is T1, the supply end timing is T2, and the supply period (first period) is P1. Then, when the combustion gas is supplied, the non-combustion gas is supplied from the second gas generating agent 233 using this thermal energy. The supply start timing of this non-combustion gas is T3, the supply end timing is T4, and the supply period (second period) is P2. As shown in FIG. 10, in this embodiment, the supply of the combustion gas is first started at the timing T1, and then the supply of the non-combustion gas is started at the timing T3. Moreover, the period P2 during which non-combustion gas is supplied from the second gas generating agent 233 is set to be longer than the period P1 during which combustion gas is supplied from the gas generator 10. By supplying the combustion gas and non-combustion gas at different timings in this manner, the maximum pressure PM at the beginning of deployment can be kept low. Furthermore, by making the non-combustion gas supply period P2 longer than the combustion gas supply period P1, the required pressure PR at which the airbag 20 functions as a cushion can be maintained for a long time, and the occupant can be protected even when multiple impacts are received due to multiple collisions, etc.

[0054] As described above, according to the airbag device 1 of the present embodiment, gas is supplied from both the gas generator 10 and the second gas generating agent 233 arranged in the bag-shaped portion 23, so that the pressure and supply amount of the combustion gas supplied from the gas generator 10 can be reduced. In addition, the gas generator 10 itself can be made smaller and lighter. Therefore, the pressure at the initial stage of deployment can be reduced, and even if the occupant moves out of the specified seating position and is near the airbag 20, adverse effects on the occupant can be suppressed, and the reliability of the airbag device 1 can be improved.

[0055] Moreover, in the airbag device 1 of this embodiment, the second gas generating agent 233 is disposed so as to face the gas discharge hole 111. This allows the high-temperature combustion gas immediately after being released from the gas discharge hole 111 to come into contact with the second gas generating agent 233, so that gas can be efficiently generated from the second gas generating agent 233. Furthermore, at this time, the second gas generating agent 233 consumes the heat of the combustion gas, so that the effect of the heat of the combustion gas on the bag-shaped portion 23 can be reduced, and the reliability of the airbag device 1 can be improved.

[0056] Furthermore, in the airbag device 1 of this embodiment, the combustion gas is supplied at a timing that is a predetermined time earlier than the timing at which gas is to be generated from the second gas generating agent, thereby making it possible to obtain appropriate EA characteristics, such as reducing the pressure at the initial stage of deployment.

[0057] <First modified example> 11 is a diagram showing an airbag device 1A according to a first modified example. The airbag device 1A of this modified example is different from the above-described embodiment in the position where the second gas generating agent 233 is arranged. Since the other configurations are the same, the same elements are given the same reference numerals and will not be described again.

[0058] In this modified example, as shown in Fig. 11, the second gas generating agent 233 is disposed at a position away from the gas discharge hole 111 of the gas generator 10 in the deployment direction. Here, the deployment direction is the direction in which the airbag 20 deploys, and further the direction in which the second gas generating agent 233 moves from the gas discharge hole 111 side before deployment to the position at which the deployment of the bag-shaped portion 23 is completed. Fig. 11 shows the state at which the deployment of the bag-shaped portion 23 is completed, and shows that the second gas generating agent 233A moves in the deployment direction indicated by the arrow 51 as the airbag 20 deploys. Thus, in this modified example, the gas discharge hole 111 of the gas generator 10 and the second gas generating agent 233A are disposed in a dispersed manner. The second gas generating agent 233A is disposed apart from the gas discharge hole 111 in the deployment direction. For example, the second gas generating agent 233A is disposed so that the distance LA from the gas discharge hole 111 to the position PA of the second gas generating agent 233A is equal to or greater than the distance L0. Here, the distance L0 is the distance to be secured between the discharge hole 111 and the second gas generating agent 233A, for example, at the time of completion of deployment, and by appropriately setting this value, the discharge hole 111, which is the gas generation source, and the second gas generating agent 233A can be appropriately distributed and disposed. Furthermore, when the airbag 20 is in a folded state before deployment, the second gas generating agent 233A may be disposed apart from the gas discharge hole 111 of the gas generator 10 in the deployment direction, and the distance L0 may be the distance to be secured between the discharge hole 111 and the second gas generating agent 233A when the airbag 20 is in a folded state. That is, the airbag 20 may be folded so that the second gas generating agent 233A is not directly opposed to the gas discharge hole 111, and the distance L0 may be secured between the discharge hole 111 and the second gas generating agent 233A in this pre-deployment state. Furthermore, the distance L0 may be a distance to be secured between the discharge hole 111 and the second gas generating agent 233A during the deployment of the airbag 20. By disposing the second gas generating agent 233A away from the gas discharge hole 111 in the deployment direction in this manner, the airbag 20 deploys initially (until the airbag 20 opens to half its size, etc.) using the combustion gas from the gas generator 10, and uses the non-combustion gas from the second gas generating agent 233A in the middle of the deployment. The distance L0 may be set depending on the size and shape of the airbag 20, the difference between the timing T1 at which the combustion gas starts to be supplied and the timing 3 at which the non-combustion gas starts to be supplied, and the like. The second gas generating agent 233B moves in the deployment direction indicated by the arrow 52, ​​and is disposed so that the shortest distance LB from the gas discharge hole 111 to the position PB at the time of completion of deployment is equal to or greater than the predetermined distance L0. Note that, since a plurality of gas discharge holes 111 are provided, the distance between the shortest one among them, i.e., the shortest distance, is set as the distance LA, LB.

[0059] In this manner, in this modification, the second gas generating agent 233 is disposed at a position on the inner surface of the airbag 20, a predetermined distance away in the deployment direction from the gas discharge hole 111. This results in the gas generation sources being disposed in a dispersed manner, and gas is supplied not only from the gas discharge hole 111 but also from the second gas generating agents 233A, 233B disposed on the deployment direction side, so that the pressure of the combustion gas supplied from the gas generator 10 can be reduced and the pressure at the initial stage of deployment can be suppressed, thereby improving the reliability of the airbag device.

[0060] <Second modified example> 12 is a diagram showing the configuration of an airbag 20 according to a second modified example. The airbag device 1B of this modified example is different from the above-mentioned embodiment in that the second gas generating agent 233 is covered with a cover member. Since the other configurations are the same, the same elements are denoted by the same reference numerals and will not be described again.

[0061] In this modification, as shown in FIG. 12, the second gas generating agent 233 is provided on the inner surface of the bag-shaped portion 23, and the inner surface is further covered with a cover member 234. As a result, even if the supply of the combustion gas is started, the combustion gas does not come into direct contact with the second gas generating agent 233. However, after the cover member 234 is consumed by the high-temperature combustion gas, the non-combustible gas is supplied from the second gas generating agent 233, so that the timing of generation of the combustible gas can be delayed. Here, the consumption of the cover member 234 means that the cover member 234 no longer fulfills the function of covering the second gas generating agent 233. For example, the cover member 234 may be made of a material that melts due to the heat of the combustion gas, and the supply of the combustion gas is started and the cover member 234 melts, so that the combustion gas comes into contact with the second gas generating agent 233, and the non-combustible gas is generated from the second gas generating agent 233. Also, instead of being limited to melting, the heat of the combustion gas may be transferred to the second gas generating agent 233 via the cover member 234, and non-combustion gas may be generated from the second gas generating agent 233 to split the cover member 234. By appropriately setting the melting temperature and thickness of the cover member 234 and adjusting the time related to the consumption, the supply timing of the non-combustion gas can be arbitrarily set. It can be set.

[0062] Note that the cover member 234 is not limited to a configuration in which it completely covers the second gas generating agent 233, and the cover member 234 may be provided so as to cover at least a portion of the second gas generating agent 233. That is, the cover member 234 may be provided on a portion (e.g., half) of the second gas generating agent 233 provided on the inner surface of the bag-shaped portion 23, and the cover member 234 may not be provided on the other portion. In this way, the non-combustion gas is generated first from the portion not provided with the cover member 234, and then the non-combustion gas is generated from the portion provided with the cover member 234, thereby making it possible to extend the supply period of the non-combustion gas as a whole.

[0063] In this way, according to this modification, the supply timing and supply period of the non-combustion gas can be set arbitrarily, and the EA characteristics can be set appropriately.

[0064] <Third modified example> 13 is a diagram showing the configuration of an airbag 20 according to a third modified example. The airbag device 1C of this modified example is different from the embodiment described above in that it is provided with a plurality of types of second gas generating agents 233 that generate non-combustion gas at different temperatures. Since the other configurations are the same, the same elements are given the same reference numerals and will not be described again.

[0065] In this modification, as shown in FIG. 13, the second gas generating agent 233C and the second gas generating agent 233D are arranged at different positions on the bag-shaped portion 23. Here, the second gas generating agent 233C is a material that generates a non-combustion gas at a higher temperature (hereinafter also referred to as a gas generating temperature) than the second gas generating agent 233D. In other words, the second gas generating agent 233D is a material that generates a gas at a lower temperature than the second gas generating agent 233C. The material of the second gas generating agent 233D is not particularly limited, and may be a sublimation material, a vaporization material, or a thermal decomposition material. For example, the second gas generating agent 233C is terephthalic acid (gas generating temperature: 333° C.) and the second gas generating agent 233D is terephthalic acid (gas generating temperature: 333° C.). The second gas generating agent 233D may be naphthalene (gas generating temperature: 209°C). The second gas generating agent 233C is sodium bicarbonate (gas generating temperature: 270°C), and the second gas The gas generating agent 233D may be an aliphatic polycarbonate (gas generating temperature: 230° C.).

[0066] The second gas generating agent 233C is disposed upstream of the second gas generating agent 233D in the flow direction of the combustion gas discharged from the gas discharge hole 111.

[0067] 13(A) shows the state immediately after the combustion gas is discharged from the gas discharge hole 111. When the discharge of the combustion gas starts, the combustion gas first comes into contact with the second gas generating agent 233C, and the second gas generating agent 233C generates non-combustion gas.

[0068] Next, as shown in Fig. 13(B), the non-combustion gas generated from the second gas generating agent 233C mixes with the combustion gas and flows downstream. Therefore, the temperature of the mixed gas of the combustion gas and the non-combustion gas is lower than that of the initial combustion gas. When this mixed gas reaches the second gas generating agent 233D, the second gas generating agent 233D uses the thermal energy of the mixed gas to generate non-combustion gas as shown in Fig. 13(C).

[0069] Then, when the generation of non-combustion gas by the second gas generating agent 233D is completed as shown in FIG. 13(D), the supply of gas is stopped.

[0070] In this way, the temperature of the combustion gas downstream drops as it mixes with the non-combustion gas. However, according to this modified example, the second gas generating agent 233D, which has a low gas generation temperature, is disposed downstream, so that the non-combustion gas can be generated efficiently without being affected by the temperature drop.

[0071] Second Embodiment 14 is a diagram showing an airbag device 1D according to a second embodiment. The airbag device 1D of this modification is different from the above-mentioned embodiment in that a deflector 110 that deflects the flow direction of the combustion gas is disposed around the gas discharge hole, and a second gas generating agent 233 is disposed in a position toward which the deflected combustion gas heads. Since the other configurations are the same, the same elements are given the same reference numerals and will not be described again.

[0072] FIG. 15 is a diagram showing the configuration of deflector 110, where (A) shows the front surface of deflector 110, (B) shows a side surface of deflector 110, (C) shows the rear surface of deflector 110, and (D) shows a cross section taken along line AA in (C).

[0073] 15(A), deflector 110 has a circular ring shape in a front view and has an opening 114 in the center into which gas generator 10 can be inserted. Deflector 110 has, on the rear side, a planar rear wall portion 115 that is attached in contact with holding base 31 of outer shell case 30, and a deflection portion 116 that is curved at the outer periphery of rear wall portion 115 into a bowl shape and extends forward. Deflector 110 can be formed, for example, by pressing a metal plate.

[0074] 14, with the rear part of gas generator 10 passing through opening 114, deflector 110 has rear wall portion 115 fixed to holding base 31 together with joints 123 and 133 of gas generator 10 by screws or the like. Deflector 110 is thus disposed around gas discharge hole 111, with deflection portion 116 curved forward being disposed to surround the outlet side of gas discharge hole 111. As a result, combustion gas discharged from gas discharge hole 111 is deflected along deflection portion 116 and guided forward as shown by arrow 150.

[0075] The second gas generating agent 233 is disposed on the inner surface of the bag-shaped portion 23 in a portion to which the combustion gas deflected by the deflector is guided, that is, on the inner center side of the front sheet 231 in this embodiment.

[0076] In this manner, in this embodiment, the deflector 110 guides the combustion gas discharged from the gas discharge hole 111 in the direction in which the second gas generating agent is located, so that the combustion gas flows intensively toward the position of the second gas generating agent 233, and gas can be efficiently generated from the second gas generating agent 233. In addition, by receiving the high-temperature combustion gas immediately after it is discharged from the gas discharge hole 111 with a metallic deflector, damage to the bag-shaped portion 23 due to the heat of the combustion gas can be prevented.

[0077] Although the airbag device according to the present disclosure has been described above, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. For example, the airbag device 1D of the second embodiment may be configured as in the first to third modified examples. In the second embodiment, when the second gas generating agent 233C is disposed upstream of the second gas generating agent 233D as in the third modified example, the upstream side and the downstream side may be set according to the flow direction of the combustion gas changed by the deflector 110. For example, in the airbag device 1D of the second embodiment, the combustion gas is directed forward by the deflector 110, strikes the vicinity of the inner center of the front sheet 231, and flows from the vicinity of the center to the peripheral side. For this reason, the vicinity of the inner center of the front sheet 231 is set as the upstream side, and the peripheral side is set as the downstream side. That is, the second gas generating agent 233C is disposed near the inner center of the front sheet 231, and the second gas generating agent 233D is disposed on the peripheral side of the second gas generating agent 233C. This makes it possible to generate non-combustion gas efficiently, similarly to the third modified example. [Explanation of symbols]

[0078] 1,1A-1D Airbag device 10 Gas Generator 11. Housing 13A Mounting hole 14 Ignition part 15 Resin retaining part 16 Filters 17 Cup-shaped cover body 18. Transfer Charge 19 Gas Generator (First Gas Generator) 20 Airbag 21 Inlet 22 Interior Space 23 Pouch 24 Retainer 30 Outer case 31 Holding base 31A Base plate section 31B Recess 32 Cover member 32A Storage space 40 Steering Wheel 42 Steering wheel 43 Boss section 44 spokes 50 Control section 60 Sensors 110 Deflector 111 Gas exhaust hole 112 Front shell 113 Rear shell 114 Aperture 115 Rear wall 116 Deflection section 121 Front peripheral wall 122 Front wall 123·133 Joint 131 Rear peripheral wall 132 Rear wall 141 Ignition part 142,142 Conductive pin 151 Base 152 Inner cylinder wall 153 Front end opening 158 Fire transmission room 160 Combustion chamber 161 Inner surface 211 Aperture 231 Front seat 232 Rear seat 233 Secondary Gas Generator 234 Cover member

Claims

1. a gas generator including a first gas generating agent that generates a combustion gas by ignition and an ignition unit that ignites the first gas generating agent; an airbag that is deployed by receiving the combustion gas from the gas generator, The airbag, an inlet portion connected to the gas generator and allowing the combustion gas supplied from the gas generator to flow into an internal space of the airbag; a bag-shaped member that separates an internal space into which the combustion gas flows from the inflow portion from an outside, the bag-shaped portion being in a folded state before receiving the supply of the combustion gas and being in an unfolded state when receiving the supply of the combustion gas; a second gas generating agent that is disposed at a predetermined position on the inner surface of the bag-shaped portion and generates gas without a combustion reaction by utilizing thermal energy of the combustion gas; Airbag device.

2. A discharge hole of the combustion gas in the gas generator is arranged toward the interior space, 2. The airbag device according to claim 1, wherein the second gas generating agent is disposed in the bag-shaped portion in the folded state so as to face the discharge hole.

3. A discharge hole of the combustion gas in the gas generator is arranged toward the interior space, 2. The airbag device according to claim 1, wherein the second gas generating agent is disposed on the inner surface of the bag-shaped portion at a position that is spaced apart from the exhaust hole in a deployment direction when the bag-shaped portion is deployed from the folded state by an inflow of the combustion gas.

4. The gas generator includes a housing having a gas exhaust hole for exhausting the combustion gas, 4. The airbag device according to claim 3, further comprising: a deflector disposed around the gas discharge hole for deflecting a flow direction of the combustion gas in a direction toward which the bag-shaped portion is deployed; and the second gas generating agent is disposed in a portion to which the combustion gas deflected by the deflector is guided.

5. 5. The airbag device according to claim 1, wherein the second gas generating agent is a substance that generates gas by being decomposed, vaporized, or sublimated by thermal energy of the combustion gas. 。

6. 6. The airbag device according to claim 1, wherein the combustion gas is supplied at a timing earlier than a timing at which the gas is to be generated from the second gas generating agent by a predetermined time. Place.

7. 7. The airbag device according to claim 1, wherein, when a period during which the combustion gas is supplied to the bag-shaped portion is defined as a first period, the second gas generating agent generates gas for a second period that is longer than the first period.

8. 8. The airbag device according to claim 1, further comprising a cover that is consumed by thermal energy of the combustion gas and is disposed so as to cover at least a portion of the second gas generating agent. 。

9. A second gas generating agent having a different reaction temperature when generating the gas is provided at a plurality of locations, Among the second gas generating agents provided at the plurality of locations, the second gas generating agent having a higher reaction temperature than the other second gas generating agents is supplied from the gas generator.

9. The airbag device according to claim 1, wherein the other second gas generating agent is disposed upstream of the other second gas generating agent in a gas flow direction.

10. A step of igniting a first gas generating agent by a gas generator including an ignition unit that ignites the first gas generating agent to generate a combustion gas; an inflow section connected to the gas generator and allowing the combustion gas supplied from the gas generator to flow into an internal space of the airbag, and a bag-shaped member separating the internal space into which the combustion gas flows from the inflow section from the outside, the bag-shaped section being in a folded state before receiving the supply of the combustion gas and being in an expanded state when receiving the supply of the combustion gas, and a second gas generating agent disposed at a predetermined position on the inner surface of the bag-shaped section, the airbag device including an airbag receiving a supply of the combustion gas generated by the ignition and starting the expansion of the bag-shaped section; generating gas from a second gas generating agent disposed in the bag-shaped portion by utilizing thermal energy of the combustion gas without involving a combustion reaction; A method for deploying an airbag device, comprising:

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