Airbag device and gas generator

Abstract

To adjust an internal pressure of an airbag by means of a simple constitution.SOLUTION: An airbag device includes: a gas generator having an ignition device, a gas generating agent that is ignited by the ignition device and generates combustion gas, and a housing accommodating the ignition device and the gas generating agent and provided with a gas discharge hole; a shielding member covering an outer side of the housing and capable of moving between a shielding position located in a discharging direction of the combustion gas from the gas discharge hole and a non-shielding position not located in the discharging direction of the combustion gas from the gas discharge hole; an elastic member disposed between the housing and the shielding member and that is urged with respect to the shielding member so that the shielding member is located at the shielding position or the non-shielding position according to a magnitude of external force received by the shielding member; and an airbag body disposed so as to communicate with inside of the housing via the gas discharge hole of the gas generator and accommodating the shielding member and the elastic member.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an airbag device.

Background Art

[0002] Conventionally, an airbag device has been proposed that includes a gas generator, a module case that houses the airbag, and a control circuit (for example, Patent Document 1). The gas generator has a plurality of gas discharge ports with different opening areas, etc., and the module case has a coolant that can move in the circumferential direction. Then, according to the instruction of the control circuit, the positions of the gas discharge port, etc. and the coolant are adjusted, and the temperature of the gas flowing into the airbag is adjusted.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When adjusting the positional relationship between the gas discharge port, etc. and the coolant using a control circuit, there is a problem that the configuration becomes complicated and miniaturization is difficult.

[0005] The technology of the present disclosure aims to enable adjustment of the internal pressure of the airbag with a simple configuration.

Means for Solving the Problems

[0006] The airbag device includes an ignition device, a gas generant that is ignited by the ignition device to generate combustion gas, and a gas generator that houses the ignition device and the gas generant and is provided with a gas discharge hole, an airbag bag body that covers the outside of the housing, a shielding member that can move to a shielding position located in the discharge direction of the combustion gas from the gas discharge hole and a non-shielding position not located in the discharge direction of the gas from the gas discharge hole, an elastic member that is disposed between the housing and the shielding member and biases the shielding member to be positioned at the shielding position or the non-shielding position according to the magnitude of the external force received by the shielding member, and is disposed so as to communicate with the inside of the housing through the gas discharge hole of the gas generator and houses the shielding member and the elastic member.

[0007] Since the shielding member can move to a shielding position located in the discharge direction of the combustion gas from the gas discharge hole and a non-shielding position not located in the discharge direction of the gas from the gas discharge hole, the shielding member can lower the temperature of the combustion gas at the shielding position. Further, since the elastic member positions the shielding member at the shielding position or the non-shielding position according to the magnitude of the external force received by the shielding member, the shielding member can be moved to the shielding position by the internal pressure of the airbag. Therefore, when the internal pressure of the airbag exceeds a predetermined standard, the shielding member can be moved to the shielding position to lower the temperature of the combustion gas. Further, by lowering the temperature of the combustion gas, an excessive increase in the internal pressure of the airbag can be suppressed. That is, the internal pressure of the airbag can be adjusted with a simple configuration.

[0008] Further, the elastic member may be extended in a state where the shielding member does not receive an external force so as to position the shielding member at the non-shielding position. The elastic member may be, for example, a coil spring or a leaf spring.

[0009] Further, the housing has an upper surface, a bottom surface, and a side surface that connects the upper surface and the bottom surface and is provided with a plurality of gas discharge holes. The shielding member has an upper portion that covers the upper surface of the housing and a peripheral wall portion that extends around the side surface from the periphery of the upper portion toward the bottom surface side. The shielding member may block the discharge direction of the combustion gas from at least some of the gas discharge holes in the shielding position. from the periphery of the upper portion toward the bottom surface side and extends around the side surface, and the shielding member may block the discharge direction of the combustion gas from at least some of the gas discharge holes in the shielding position.

[0010] Further, the side surface of the shielding member may include a filter. By doing so, the cooling efficiency of the combustion gas is improved.

[0011] Further, the plurality of gas discharge holes include a first gas discharge hole provided on the upper side of the upper surface on the side surface and a second gas discharge hole provided on the bottom side of the first gas discharge hole on the side surface, and the shielding member may be configured to face the first gas discharge hole at the shielding position and not face the first gas discharge hole at the non-shielding position.

[0012] Further, the plurality of gas discharge holes are each blocked by a blocking member, and the pressure required to crack the blocking member blocking the first gas discharge hole may be higher than the pressure required to crack the blocking member blocking the second gas discharge hole.

[0013] Further, the upper surface of the shielding member may be a flat plate without holes. If a gas discharge hole is provided on the upper surface of the gas generator, the combustion gas discharged from the gas discharge hole collides with the shielding member regardless of the shielding position or the non-shielding position and pushes the shielding member upward. If a gas discharge hole is provided on the side surface and no gas discharge hole is provided on the upper surface, in the configuration where the bottomed cylindrical shielding member 4 is placed on the upper part of the upper shell 211, the change in the position of the shielding member 4 according to the internal pressure of the airbag bag body 3 can be easily controlled.

[0014] Further, the upper surface of the shielding member may have a shape similar to the upper surface of the gas generator. By doing so, in the configuration where the shielding member is stacked on the gas generator, the entire airbag can be formed compactly. Also, in a plan view, the shielding member is a circular shape larger than the gas generator, and the shielding member or the gas generator may be provided with a spacer portion that forms a gap between the shielding member and the gas generator. By doing so, the shielding member can move between the shielding position and the non-shielding position while appropriately maintaining the gap with the gas generator.

[0015] Further, a guide portion may be provided so as to sandwich a shielding member between the guide portion and the gas generator, and the guide portion may guide the moving direction of the shielding member and regulate the moving range of the shielding member.

[0016] The guide portion may be a porous member provided between the shielding member and the airbag bag body and having a plurality of holes through which combustion gas can pass.

[0017] It may further include a base plate connected to the gas generator and the airbag bag body, and at least one of the airbag bag body and the base plate may have an openable and closable variable vent for discharging a part of the combustion gas when the internal pressure of the airbag bag body exceeds a predetermined threshold value. Even in this way, an excessive increase in the internal pressure of the airbag can be suppressed. That is, the internal pressure of the airbag can be adjusted with a simple configuration.

[0018] The contents described in the means for solving the problems can be combined as much as possible without departing from the problems and technical ideas of the present disclosure.

Advantages of the Invention

[0019] According to the present disclosure, the internal pressure of the airbag can be adjusted with a simple configuration.

Brief Description of the Drawings

[0020]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

DETAILED DESCRIPTION OF THE INVENTION

[0021] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. Note that each configuration and their combinations in each embodiment are examples, and within the scope not departing from the gist of the present invention, additions, omissions, substitutions, and other changes of the configuration can be made as appropriate. The present disclosure is not limited by the embodiments, but is limited only by the scope of the claims.

[0022] <Embodiment 1> FIG. 1 is an axial schematic cross-sectional view showing an example of an airbag according to the present embodiment. The airbag 1 is incorporated, for example, in a steering wheel or a dashboard of an automobile. The airbag 1 in FIG. 1 includes a gas generator 2, an airbag bag body 3, a shielding member 4, an elastic member 5, and a base plate 6, and the gas generator 2 and the airbag bag body 3 are connected to the base plate 6. For convenience, as shown by the arrows in FIG. 1 indicating the vertical direction, the direction in which the airbag bag body 3 expands with reference to the gas generator 2 will be described as upward.

[0023] <Gas generator> The gas generator 2 is ignited by an externally supplied current, burns a gas generating agent provided therein, and discharges combustion gas. The gas generator 2 illustrated in FIG. 1 is a single-type device having one igniter 22, but is not limited to such an example, and an existing gas generator such as a so-called dual-type device can be used.

[0024] The gas generator 2 in FIG. 1 includes a housing 21, an igniter 22, a filter 23, and a first gas generating agent 24. The gas generator 2 operates an igniter main body 221 disposed in the housing 21 to burn the first gas generating agent 24 filled inside the housing 21 and discharge combustion gas.

[0025] The housing 21 is formed in a short cylindrical shape with both axial ends closed by joining a metal upper shell 211 and a lower shell 212, each formed in a bottomed cylindrical shape, with their open ends facing each other. However, the configurations of the upper shell 211 and the lower shell 212 are not limited to this, and known ones can be used as appropriate.

[0026] The upper shell 211 includes a cylindrical upper tube portion 2112, a top plate portion 2111 that closes the upper end of the upper tube portion 2112, and a flange-shaped joint portion that extends radially outward from the lower end portion of the upper tube portion 2112 It has 2113. Further, the lower shell 212 has a cylindrical lower cylinder portion 2122, a bottom plate portion 2121 that closes the lower end of the lower cylinder portion 2122, and a flange-shaped joint portion 2123 that extends radially outward from the upper end portion of the lower cylinder portion 2122. The housing 21 is formed by overlapping the joint portion 2113 of the upper shell 211 and the joint portion 2123 of the lower shell 212 and joining them by welding or the like. Further, the upper shell 211 is inserted into a holding hole 61 provided in the base plate 6, and the joint portion 2113 or the joint portion 2123 and the peripheral edge portion of the holding hole 61 of the base plate 6 are welded, for example. The holding hole 61 provided in the base plate 6 is an opening that is larger than the outer diameter of the upper cylinder portion 2112 and smaller in diameter than the joint portion 2113.

[0027] Further, a plurality of first gas discharge holes 2114 and second gas discharge holes 2115 that communicate the inside and outside of the housing 21 are formed side by side along the circumferential direction in the upper cylinder portion 2112 of the upper shell 211. As shown in FIG. 1, the first gas discharge hole 2114 is provided above the second gas discharge hole 2115. Also, in the example of FIG. 1, the opening area per one of the first gas discharge holes 2114 is smaller than the opening area per one of the second gas discharge holes 2115, but the example is not limited to this. Before the operation of the gas generator 2, the first gas discharge hole 2114 and the second gas discharge hole 2115 are closed by a closing member (not shown) such as a sealing tape. The sealing tape is a member having non-moisture permeability with a thickness of, for example, about 50 to 100 μm. Note that gas discharge holes may be provided at three or more different positions in the vertical direction. Also, gas discharge holes may be provided in the top plate portion 2111.

[0028] Further, an igniter 22 is connected to the lower shell 212 of the housing 21. The igniter 22 includes an igniter body 221 that is ignited by an ignition current, an igniter holding portion 222 that supports the igniter body 221, a fixing portion 223 interposed between the igniter body 221 and the igniter holding portion 222, a second gas generating agent 224 that is ignited by the combustion products of the igniter body 221, and a case 225 that houses the second gas generating agent 224 and the like.

[0029] The igniter body 221 has a metal cup body that houses and seals the ignition charge, and a pair of conductive pins for receiving a current supply from the outside. The igniter body 221 operates by the ignition current supplied to the pair of conductive pins to burn the ignition charge in the cup body and release the combustion products to the outside of the cup body.

[0030] The igniter holder 222 is, for example, a metal collar that supports the side of the igniter body 221. That is, the igniter holder 222 is a metal member formed in a cylindrical shape. Further, the igniter holder 222 holds the igniter body 221 inside thereof. In addition, in order to suppress the circumferential rotation of the igniter body 221 and the fixing portion 223, irregularities may be provided on the inner circumferential surface of the igniter holder 222 that contacts the fixing portion 223. Also, the shape of the hole through which the conductive pin penetrates may have a shape other than a perfect circle, such as a polygon or an ellipse, in a cross-sectional view. Further, the igniter holder 222 may be fixed to the housing 21 of the gas generator 2, for example, by welding or the like. Note that the igniter holder 222 may be formed integrally with the bottom plate portion 2121. That is, a metal igniter holder 222 may be formed by a part of the lower shell 212 of the housing 21. In this case, the igniter holder 222 is provided so as to protrude upward from the bottom plate portion 2121 inside the housing 21.

[0031] The fixing portion 223 is a resin member interposed between the igniter body 221 and the igniter holder 222 by injection molding to fix the igniter body 221 to the igniter holder 222. The fixing portion 223 covers the periphery of the side of the igniter body 221 so that at least a part of the cup body is exposed from the fixing portion 223. Also, the fixing portion 223 engages with the inside of the igniter holder 222 to fix the igniter body 221 to the igniter holder 222. However, the entire cup body may be overmolded by the fixing portion 223. That is The entire cup body may be covered with resin. Further, the fixing portion 223 may form a connector insertion space 226 inside the igniter holding portion 222 into which a connector (not shown) for supplying power from an external power source to a pair of conductive pins can be inserted. The fixing portion 223 covers and holds a part of the pair of conductive pins such that the lower ends of the pair of conductive pins are exposed in the connector insertion space 226. And the fixing portion 223 maintains the insulation between the pair of conductive pins. Note that various known techniques can be used for fixing the igniter body 221 and the igniter holding portion 222 and for the connection relationship between the igniter holding portion 222 and the housing. Also, as the material of the fixing portion 223, a resin material excellent in heat resistance, durability, corrosion resistance, etc. after curing can be preferably used.

[0032] The case 225 is a bottomed cylindrical member that extends upward from the igniter holding portion 222 so as to surround the upper part of the igniter 22. That is, the case 225 is formed in a cylindrical shape with one end (upper end) closed and the other end (lower end) open. Also, the other end of the case 225 may be formed in a flange shape and connected to the igniter holding portion 222 by, for example, full - circumference welding. A combustion chamber 227, which is an internal space for accommodating the second gas generating agent 224, is formed between the case 225 and the igniter holding portion 222. The second gas generating agent 224 burns by the operation of the igniter body 221 and generates combustion gas and the like. Also, a plurality of communication holes 228 that communicate the combustion chamber 227 with the external space are provided on the side surface of the case 225. The communication holes 228 are closed by a closing member (not shown) such as a sealing tape in a state before the igniter 22 operates. Also, when the igniter 22 operates, the sealing tape is cracked by the pressure of the combustion gas, and the combustion gas is discharged from the communication holes 228 to the outside of the combustion chamber 227. Also, the communication holes 228 may be formed on the top surface instead of the side surface of the case 225.

[0033] The first gas generating agent 24 and the second gas generating agent 224 may be gas generating agents having the same type, shape, dimensions, etc., or at least a part of them may be different gas generating agents. The first gas generating agent 24 and the second gas generating agent 224 generate combustion products such as combustion gas by burning. The individual shapes of the first gas generating agent 24 and the second gas generating agent 224 can be, for example, single-hole cylindrical ones, but are not limited thereto.

[0034] The filter 23 may be formed by winding a sheet-like porous plate such as expanded metal, perforated metal, metal lath, plain woven wire mesh, or twill woven wire mesh into a cylindrical shape. The filter 23 is disposed between the igniter 22 and the first gas discharge hole 2114 and the second gas discharge hole 2115 in a state where the upper end portion is supported by the top plate portion 2111 of the upper shell 211 and the lower end portion is supported by the bottom plate portion 2121 of the lower shell 212. Thereby, a combustion chamber 25 is formed between the igniter 22 and the filter 23. The combustion chamber 25 is filled with the first gas generating agent 24 that burns by the operation of the igniter 22. The first gas generating agent 24 is ignited by the combustion gas of the second gas generating agent 224 that has burned by the operation of the igniter 22 and generates combustion gas and the like. The filter 23 is configured to allow the combustion gas to pass through, and the combustion gas in the combustion chamber 25 is cooled by passing through the filter 23, and the filter 23 filters the combustion gas by collecting the combustion residues of the combustion gas.

[0035] <Airbag bag body> The airbag bag body 3 is a bag-shaped member that expands, for example, into a substantially spherical shape by containing the combustion gas discharged by the gas generator 2 inside it. In FIG. 1, the airbag bag body 3 schematically represents the folded state before inflation. The airbag bag body 3 is provided with a gas inlet 31 that opens, for example, in a circular shape at the lower part, and a plurality of mounting holes 32 are formed at the periphery of the gas inlet 31. For example, bolts 62 are inserted into the mounting holes 32, and the airbag bag body 3 is connected to the base plate 6 by the bolts 62. Note that bolt holes 63 are formed at the peripheral part of the holding holes 61 of the base plate 6. That is, the airbag bag body 3 is connected to the gas generator 2 via the base plate 6. And the gas discharge holes (the first gas discharge hole 2114 and the second gas discharge hole 2115) of the gas generator 2 open toward the inside of the airbag bag body 3. In other words, the airbag bag body 3 is arranged to communicate with the inside of the gas generator 2 via the first gas discharge hole 2114 and the second gas discharge hole 2115 of the gas generator 2. Further, a shielding member 4 and an elastic member 5 are accommodated between the airbag bag body 3 and the gas generator 2.

[0036] <Shielding member> The shielding member 4 is a bottomed cylindrical member. That is, the shielding member 4 has a cylindrical bottom part 41 and a side peripheral part 42. Further, the shielding member 4 is accommodated inside the airbag bag body 3 and covers the upper part of the housing 21 of the gas generator 2. Specifically, the shielding member 4 covers the top plate part 2111 of the upper shell 211 and a part of the upper cylindrical part 2112. Note that the inner diameter of the shielding member 4 is larger than the outer diameter of the upper shell 211 so that a gap is formed between the upper shell 211 of the gas generator 2 and the shielding member 4. The shielding member 4 is connected to the housing 21 via the elastic member 5. The elastic member 5 is a member having elasticity such as a metal coil spring. The elastic member 5 holds the position of the shielding member 4 so that it can be changed with respect to the gas generator 2. For example, the elastic member 5 biases the shielding member 4 by extending upward in the direction in which the airbag bag body 3 expands in a state where no external force is applied. Further, the position of the shielding member 4 moves in the vertical direction according to the magnitude of the external force received by the shielding member 4.

[0037] During the operation of the airbag 1, the shielding member 4 can move between a shielding position located in the discharge direction of the combustion gas from the first gas discharge hole 2114 and a non-shielding position not located in the discharge direction of the combustion gas from the first gas discharge hole 2114 according to the internal pressure of the airbag bag body 3. FIG. 2 is a diagram for explaining the position of the shielding member 4. In FIG. 2, only the housing 21 and the shielding member 4 are shown. (A) of FIG. 2 is a side view showing an example of the shielding member 4 located at the non-shielding position. (B) of FIG. 2 is a side view showing an example of the shielding member 4 located at the shielding position. The non-shielding position is a position where the shielding member 4 is pushed upward by the elastic member 5 and the shielding member 4 does not block the discharge direction of the combustion gas from the first gas discharge hole 2114. In other words, at the non-shielding position, the inside of the shielding member 4 does not face the first gas discharge hole. As shown in (A) of FIG. 2, at the non-shielding position, the first gas discharge hole 2114 is not covered by the shielding member 4. The shielding position is a position where the shielding member 4 is pushed downward by the internal pressure of the airbag bag body 3 and the shielding member 4 blocks the discharge direction of the combustion gas from the first gas discharge hole 2114. In other words, at the shielding position, the inside of the shielding member 4 faces the first gas discharge hole. As shown in (B) of FIG. 2, at the shielding position, the first gas discharge hole 2114 is covered by the shielding member 4. Note that the vertical size of the shielding member 4 (side peripheral portion 42) is such that it is not located in the gas discharge direction from the second gas discharge hole 2115 even when the shielding member 4 is pushed downward to the lowest position. Also, even at the shielding position, since there is a gap between the gas generator 2 and the shielding member 4, the combustion gas discharged from the first gas discharge hole 2114 moves inside the shielding member 4 and then into the airbag bag body 3 after colliding with the shielding member 4. At this time, the temperature of the combustion gas decreases by contacting the shielding member 4. Note that the shielding member 4 preferably has a high thermal conductivity. The material of the shielding member 4 may be a metal such as aluminum or copper, or a ceramic, graphite, etc. In addition, the inside of the shielding member 4 may have irregularities such as protrusions. By increasing the surface area of the shielding member 4, the area that can come into contact with the combustion gas increases, and the cooling effect can be enhanced. Also, the shielding member 4 may include a filter.For example, the shielding member 4 may further include the above-described filter 23 inside the side peripheral portion 42, or the side peripheral portion 42 may be formed of the same material as the filter 23. By doing so, the cooling efficiency of the combustion gas is improved.

[0038] <Effect> Generally, when the airbag expands excessively during a vehicle collision, it may not be able to properly restrain the occupant and may cause an impact to the occupant. Conversely, if the inflation of the airbag is insufficient the occupant cannot be properly restrained either.

[0039] The internal pressure of the airbag changes according to the amount of substance (number of moles) of the combustion gas discharged per unit time. For example, the reaction rate in the combustion of the gas generant changes according to the ambient temperature where the gas generator 2 is installed. That is, as the ambient temperature rises, the combustion rate of the gas generant also increases. Also, in a dual-type gas generator (not shown), two combustion chambers for housing the igniter and the gas generant are provided, and it can operate in a mode where only one is activated, a mode where both are activated simultaneously, or a mode where both are activated with a time difference. Due to such differences in the operation modes, the physical quantity of the combustion gas discharged per unit time also changes.

[0040] When the internal pressure of the airbag bag body 3 exceeds the designed threshold value, the shielding member 4 and the elastic member 5 are designed such that the shielding member 4 moves to the shielding position by the pressure. Further, when the shielding member 4 is located at the shielding position, the combustion gas discharged from the first gas discharge hole 2114 collides with the shielding member 4 and its temperature decreases. Thereby, the difference in the output of the gas generator 2 due to the difference in the ambient temperature during operation can be suppressed to a small level. That is, when the internal pressure of the airbag bag body 3 exceeds a predetermined threshold value, the shielding member 4 moves to the shielding position to cool the combustion gas, thereby suppressing the increase in the pressure inside the airbag bag body 3. Therefore, the airbag bag body 3 is suppressed from expanding excessively. On the other hand, when the internal pressure of the airbag bag body 3 is equal to or lower than the designed threshold value, the shielding member 4 is located at the non-shielding position. At this time, the temperature of the combustion gas discharged into the airbag bag body 3 does not decrease. Therefore, according to the shielding member 4 of the airbag 1, the occurrence of excessive expansion or insufficient expansion of the airbag bag body 3 can be suppressed. Further, since the shielding member 4 is moved by the internal pressure of the airbag bag body 3, the airbag 1 does not require a complicated configuration for driving the shielding member 4. That is, the internal pressure of the airbag can be adjusted with a simple configuration.

[0041] As shown in FIGS. 1 and 2, the individual opening areas may be such that the second gas discharge hole 2115 is larger than the first gas discharge hole 2114. For example, when closing the gas discharge holes with sealing tapes of the same thickness, the sealing tape of the second gas discharge hole 2115 with a larger opening area will crack first. That is, the pressure required to crack the sealing tape closing the first gas discharge hole 2114 is higher than the pressure required to crack the sealing tape closing the second gas discharge hole 2115. In this way, the second gas discharge hole 2115 will open first, and the inflation of the airbag bag body 3 can be started promptly. Also, for example, when the environmental temperature is high and the amount of combustion gas generated per unit time is relatively large, the first gas discharge hole 2114 will also continue to open. Further, when the internal pressure of the airbag bag body 3 rises beyond a predetermined standard, the combustion gas is cooled by the shielding member 4 that moves to the shielding position due to the pressure increase inside the airbag bag body 3, and the further increase in the internal pressure of the airbag bag body 3 can be suppressed. On the other hand, when the amount of combustion gas generated per unit time is relatively small, the first gas discharge hole 2114 will not open until combustion progresses sufficiently and the internal pressure of the gas generator 2 becomes sufficiently high. Also, even if the first gas discharge hole 2114 opens, the shielding member 4 will not move to the shielding position if the pressure of the airbag bag body 3 is below a predetermined value. Therefore, the combustion gas is not excessively cooled.

[0042] Also, if a gas discharge hole is provided in the top plate portion 2111, the cylindrical bottom portion 41 of the shielding member 4 is formed in a donut shape with one hole in the central portion, so that the combustion gas from the gas discharge hole in the top plate portion 2111 is discharged toward the central portion. In this case, when the shielding member 4 is in the non-shielding position (when the cylindrical bottom portion 41 is separated from the top plate portion 2111), the combustion gas hardly collides with the shielding member, and when the shielding member 4 is in the shielding position (when the cylindrical bottom portion 41 is close to the top plate portion 2111), the combustion gas collides with the shielding member. On the other hand, as shown in FIG. 1, if a gas discharge hole is provided only in the upper cylindrical portion 2112 and no gas discharge hole is provided in the top plate portion 2111, in the configuration where the bottomed cylindrical shielding member 4 is placed on the upper part of the upper shell 211, the change in the position of the shielding member 4 according to the internal pressure of the airbag bag body 3 can be easily controlled.

[0043] The shielding member 4 and the gas generator 2 may have similar shapes in plan view. By doing so, in the configuration where the shielding member 4 is overlapped on the upper part of the gas generator 2, no wasted space is generated, and the entire airbag 1 can be miniaturized.

[0044] <Embodiment 2> FIG. 3 is a schematic cross-sectional view showing an example of an airbag according to the second embodiment. FIG. 4 is a perspective view showing an example of an elastic member. In this embodiment, components corresponding to the components in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0045] The elastic member 5A according to this embodiment includes a flat base portion 51 and a plurality of leaf springs 52. The number of leaf springs is not particularly limited, but is, for example, three. The leaf spring 52 is formed, for example, by forming a U-shaped slit in a metal base portion 51 and raising a tongue piece portion whose outer edge is defined by the slit upward. The raised tongue piece portion may form a curved surface such as an arc-shaped longitudinal section, for example. Further, the base portion 51 may be circular in plan view, for example. The base portion 51 can be connected to the upper side of the gas generator 2 by welding or the like.

[0046] Also with such an elastic member 5A, the shielding member 4 can be urged so as to be positioned at the shielding position or the non-shielding position according to the magnitude of the external force received by the shielding member 4.

[0047] <Embodiment 3> FIG. 5 is a schematic cross-sectional view showing an example of an airbag according to the third embodiment. Also in this embodiment, components corresponding to the components in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0048] In the example of FIG. 5, inside the airbag bag body 3 and outside the shielding member 4, a porous member 7 having a plurality of holes through which combustion gas can pass is further provided. The porous member 7 is a bottomed cylindrical member, and includes a cylindrical bottom portion 71, a side peripheral portion 72, and a flange portion 73 provided at the lower end of the side peripheral portion 72 and extending radially outward. The side peripheral portion 72 is, for example, circular in a plan view (not shown), and the diameter of the side peripheral portion 72 is larger than the diameter of the side peripheral portion 42 of the shielding member 4. The flange portion 73 is provided with mounting holes 74 which are through holes at positions corresponding to the bolt holes 63 of the base plate 6. For example, bolts 62 are inserted into the mounting holes 74, and the porous member 7 is fixed to the base plate 6 by the bolts 62 together with the airbag bag body 3. The plurality of holes are provided at least in the cylindrical bottom portion 71 and the side peripheral portion 72, and the combustion gas generated by the gas generator 2 passes through the holes provided in the side peripheral portion 72 and is discharged into the airbag bag body 3. Also, the gas pressures inside and outside the porous member 7 are substantially the same, and when the internal pressure of the airbag bag body 3 increases, the shielding member 4 is pushed downward.

[0049] Further, the height of the side peripheral portion 72 of the porous member 7 is such that it does not prevent the movement of the shielding member 4 to the non-shielding position. For example, when the shielding member 4 is in the non-shielding position, the distance from the first gas discharge hole 2114 to the cylindrical bottom portion 71 of the porous member 7 is greater than the height of the side peripheral portion 42 of the shielding member 4. Thus, in a state where the shielding member 4 is in contact with the inside of the cylindrical bottom portion 71 of the porous member 7, the side peripheral portion 42 of the shielding member 4 does not face the first gas discharge hole 2114. Also, the height of the side peripheral portion 42 of the shielding member 4 is greater than the distance from the top plate portion 2111 of the upper shell 211 to the cylindrical bottom portion 71 of the porous member 7. Thus, the side peripheral portion 42 of the shielding member 4 does not come off from between the upper cylindrical portion 2112 of the upper shell 211 of the gas generator 2 and the side peripheral portion 72 of the porous member 7. Also, the side peripheral portion 42 of the shielding member 4 is guided along between the upper cylindrical portion 2112 of the upper shell 211 of the gas generator 2 and the side peripheral portion 72 of the porous member 7 and moves between the shielding position and the non-shielding position This is how it is done. In this way, the porous member 7 is arranged with the side peripheral portion 42 of the shielding member 4 sandwiched therebetween and the gas generator 2, and functions as a guide portion that guides the moving direction of the shielding member 4 and restricts the moving range of the shielding member 4. Further, even when the airbag bag body 3 is in a folded state before the operation of the airbag 1, the shielding member 4 does not interfere with the airbag bag body 3. Therefore, before the operation of the airbag 1, the shielding member 4 can maintain the non-shielding position. Also, during the operation of the airbag 1, combustion gas can be smoothly supplied to the inside of the airbag bag body 3, and the airbag bag body 3 can be quickly deployed.

[0050] <Embodiment 4> FIG. 6 is a schematic cross-sectional view showing an example of an airbag according to the fourth embodiment. FIG. 7 is a perspective view showing an example of a base plate, a gas generator, and a shielding member. In this embodiment as well, the components corresponding to the components in the above-described embodiment are denoted by the same reference numerals, and the description thereof is omitted.

[0051] In this embodiment, the shielding member 4 is provided at the lower end portion of the side peripheral portion 42 and has a flange portion 43 that protrudes outward in the radial direction. Further, the base plate 6 has a support portion 64 that extends upward at the peripheral edge portion of the holding hole 61, and a hook 65 that is provided at the tip of the support portion 64 and protrudes inward in the radial direction of the holding hole 61. The support portion 64 may be connected to the base plate 6 by welding or the like. In this embodiment, in a state where the shielding member 4 does not receive an external force of a predetermined magnitude or more directed downward, the flange portion 43 and the hook 65 are engaged, and the shielding member 4 is prevented from coming off the gas generator 2 and the base plate 6.

[0052] The support portion 64 and the hook 65 according to this embodiment are also arranged with the side peripheral portion 42 of the shielding member 4 sandwiched therebetween and the gas generator 2, and function as a guide portion that guides the moving direction of the shielding member 4 and restricts the moving range of the shielding member 4.

[0053] <Embodiment 5> FIG. 8 is a schematic cross-sectional view showing an example of an airbag according to the fifth embodiment. FIG. 9 is a perspective view showing an example of a pedestal. In this embodiment as well, components corresponding to the components in the above-described embodiments are denoted by the same reference numerals, and the description thereof is omitted.

[0054] In this embodiment, the elastic member 5, which is a coil spring, is connected to the gas generator 2 via the pedestal 53. As shown in FIG. 9, the pedestal 53 has a connection portion 531 connected to the gas generator 2, for example, by welding, a leg portion 532 rising obliquely upward, and a flat portion 533 connected to the elastic member 5. The connection portion 531 and the leg portion 532 are respectively formed at the four corners of the rectangular flat portion 533. For example, the elastic member 5 may be a resin coil spring, and one of its ends may be fixed to the flat portion 533 using a screw or the like. Also, the other end of the elastic member 5 may be fixed to the shielding member 4 using a screw or the like.

[0055] Generally, when the gas generator 2 operates, the heat accumulated in the internal filter 23 is transmitted to the housing 21. In this embodiment, a gap is provided between the elastic member 5 and the gas generator 2 by the pedestal 53 to make it difficult for heat to be transmitted to the elastic member 5. Also, the material of the elastic member 5 may be a silicon resin or a polyimide resin having a predetermined heat resistance.

[0056] <Embodiment 6> FIG. 10 is a schematic cross-sectional view showing an example of an airbag according to the sixth embodiment. FIG. 11 is a cross-sectional view taken along line A-A in FIG. 10 of the gas generator and the shielding member. In this embodiment as well, components corresponding to the components in the above-described embodiments are denoted by the same reference numerals, and the description thereof is omitted.

[0057] In this embodiment, the side peripheral portion 42 of the shielding member 4 is provided with a spacer portion 44 that protrudes inward. The spacer portion 44 is provided in a part of the circumferential direction. In the example of FIG. 11, three spacer portions 44 are provided at equal intervals in the circumferential direction, but the number and positions of the spacer portions 44 are not limited to the illustrated example. Also, along the inner circumference of the side peripheral portion 42, there is a gap between the spacer portions 44, and a flow path for combustion gas is formed between the shielding member 4 and the gas generator 2. The spacer portion 44 protrudes toward the side surface of the gas generator 2, but it does not have to be in contact with the side surface of the gas generator 2. Also, the spacer portion 44 may be formed by deforming the side peripheral portion 42 of the shielding member 4 from the outside toward the inside. By providing three or more spacer portions 44, for example, at substantially equal intervals, the cross-sectional shape of the flow path for combustion gas becomes non-uniform, and when the airbag 1 is actuated and the shielding member 4 moves to the shielding position, the amount of combustion gas discharged from between the gas generator 2 and the shielding member 4 to the surroundings becomes non-uniform, and the airbag bag body 3 expands evenly around it. Note that instead of the shielding member 4, the gas generator 2 may be provided with a spacer portion so as to protrude outward therefrom.

[0058] <Embodiment 7> FIG. 12 is a diagram for explaining the operation during inflation of the airbag according to the seventh embodiment. Also in this embodiment, components corresponding to the components in the above-described embodiments are denoted by the same reference numerals, and the description thereof is omitted.

[0059] The airbag bag body 3 according to this embodiment is provided with a variable vent on the side opposite to the gas inlet 31, which can be opened and closed by the internal pressure of the airbag bag body 3. The variable vent covers an exhaust port opened in the airbag bag body 3 with a closing member 33. The closing member 33 is connected to the airbag bag body 3 by a stitching member such as an elastic thread. Fig. 12(A) shows a state where the internal pressure of the airbag bag body 3 is below a predetermined threshold value. In Fig. 12(A), the closing member 33 of the variable vent closes the exhaust port. Fig. 12(B) shows a state where the internal pressure of the airbag bag body 3 exceeds a predetermined threshold value. In Fig. 12(B), the stitching member 34 extends due to the internal pressure of the airbag bag body 3, and the exhaust port is open. With such a variable vent, the internal pressure of the airbag 1 can be further adjusted. Generally, the airbag bag body 3 is provided with a vent hole (not shown) for gradually discharging the internal combustion gas. In this embodiment, in addition to such a vent hole, a variable vent is provided in the airbag bag body 3.

[0060] <Embodiment 8> Fig. 13 is a diagram for explaining the operation of the airbag according to the eighth embodiment during inflation. In this embodiment as well, the components corresponding to the components in the above-described embodiments are denoted by the same reference numerals, and the description thereof is omitted.

[0061] The base plate 6 according to this embodiment is provided with a variable vent that can be opened and closed by the internal pressure of the airbag bag body 3. The variable vent according to this embodiment includes an exhaust port 68 provided in the base plate 6, a rubber packing 66 biased by a coil spring 67 or the like from below the base plate 6, and a movable member 69 connected above the rubber packing 66. The movable member 69 is arranged so as to be able to penetrate the exhaust port 68 in the vertical direction, and the movable range of the rubber packing 66 is limited in the vertical direction. (A) of FIG. 13 shows a state where the internal pressure of the airbag bag body 3 is below a predetermined threshold value. In (A) of FIG. 13, the rubber packing 66 biased by the coil spring 67 of the variable vent closes the exhaust port 68. (B) of FIG. 13 shows a state where the internal pressure of the airbag bag body 3 exceeds a predetermined threshold value. In (B) of FIG. 13, the rubber packing 66 is pushed down against the coil spring 67 by the internal pressure of the airbag bag body 3, and the exhaust port 68 is open. With such a variable vent, the internal pressure of the airbag 1 can also be adjusted.

[0062] <Others> As described above, the embodiments of the igniter assembly and the gas generator according to the present disclosure have been described. However, each aspect disclosed in this specification can be combined with other features disclosed in this specification. For example, at least one or more of the shielding member and the elastic member described in Embodiments 1, 2, or 5 can be combined with the guide portion shown in Embodiments 3 and 4, the spacer portion shown in Embodiment 6, and the variable vent shown in Embodiments 10 and 11.

Description of Reference Numerals

[0063] 1: Airbag 2: Gas generator 21: Housing 211: Upper shell 2114: First gas discharge hole 2115: Second gas discharge hole 212: Lower shell 22: Igniter 23: Filter 24: First gas generating agent 25: Combustion chamber 3: Airbag bag body 31: Gas inlet 32: Mounting hole 33, 34: Variable vent 4: Shielding member 41: Cylindrical bottom part 42: Side peripheral part 43: Flange part 44: Spacer part 5, 5A: Elastic member 51: Base part 53: Pedestal 531: Connection part 532: Leg part 533: Flat part 6: Base plate 61: Holding hole 62: Bolt 63: Bolt hole 64: Support part 65: Hook 66 - 69: Variable vent 7: Porous member 71: Cylindrical bottom part 72: Side peripheral part 73: Flange part 74: Mounting hole

Claims

1. An airbag device comprising: an ignition device; a gas generating agent that is ignited by the ignition device to generate combustion gas; and a gas generator that houses the ignition device and the gas generating agent and is provided with a gas discharge hole. A shielding member that covers the outside of the housing and is movable between a shielding position located in the discharge direction of the combustion gas from the gas discharge hole and a non-shielding position not located in the discharge direction of the combustion gas from the gas discharge hole. An elastic member disposed between the housing and the shielding member that biases the shielding member in a direction from the shielding position to the non-shielding position, and is capable of positioning the shielding member at the shielding position or the non-shielding position according to the magnitude of an external force received by the shielding member. An airbag bag body disposed to communicate with the inside of the housing through the gas discharge hole of the gas generator and that houses the shielding member and the elastic member. An airbag device comprising the above components.

2. The elastic member extends in a state where the shielding member does not receive an external force, and positions the shielding member at the non-shielding position. The airbag device according to Claim 1.

3. The housing has an upper surface, a bottom surface, and a side surface that connects the upper surface and the bottom surface and is provided with a plurality of the gas discharge holes. The shielding member has an upper portion that covers the upper surface of the housing and a peripheral wall portion that extends around the side surface from the periphery of the upper portion toward the bottom surface side. The shielding member blocks the discharge direction of the combustion gas from at least a part of the gas discharge holes in the shielding position. The airbag device according to Claim 1 or 2.

4. The side surface of the shielding member includes a filter. The airbag device according to Claim 3.

5. The gas discharge holes include a first gas discharge hole provided on the side surface on the side of the upper surface and a second gas discharge hole provided on the side surface on the side of the bottom surface and below the first gas discharge hole. The shielding member faces the first gas discharge hole in the shielding position. does not face the first gas discharge hole in the non-shielding position. The airbag device according to Claim 3 or 4.

6. The gas discharge holes are each blocked by a blocking member. The pressure required to crack the blocking member that blocks the first gas discharge hole is higher than the pressure required to crack the blocking member that blocks the second gas discharge hole. The airbag device according to Claim 5.

7. The upper surface of the shielding member is a flat plate shape without holes. The airbag device according to any one of claims 3 to 6.

8. The upper surface of the shielding member has a shape similar to the upper surface of the gas generator. The airbag device according to any one of claims 3 to 7.

9. In plan view, the shielding member is a circle larger than the gas generator, and the shielding member or the gas generator includes a spacer portion that forms a gap between the shielding member and the gas generator. The airbag device according to claim 8.

10. Further provided so as to sandwich the shielding member between the gas generator, and further including a guide portion that guides the moving direction of the shielding member and restricts the moving range of the shielding member. The airbag device according to any one of claims 1 to 9.

11. The guide portion is provided between the shielding member and the airbag bag body, and is a porous member having a plurality of holes through which the combustion gas can pass. The airbag device according to claim 10.

12. Further including a base plate connected to the gas generator and the airbag bag body. At least one of the airbag bag body and the base plate has a variable vent that can be opened and closed according to the internal pressure of the airbag bag body, and discharges a part of the combustion gas when the internal pressure of the airbag bag body exceeds a predetermined threshold value. The airbag device according to any one of claims 1 to 11.

13. An ignition device, a gas generating agent that is ignited by the ignition device to generate combustion gas, and a housing that houses the ignition device and the gas generating agent and is provided with a gas discharge hole. A shielding member that covers the outside of the housing and can move to a shielding position located in the discharge direction of the combustion gas from the gas discharge hole and a non-shielding position not located in the discharge direction of the combustion gas from the gas discharge hole. A member disposed between the housing and the shielding member, which biases the shielding member in a direction from the shielding position to the non-shielding position, and can position the shielding member at the shielding position or the non-shielding position according to the magnitude of the external force received by the shielding member. An elastic member. A gas generating device comprising.

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