Gas generator

Abstract

To provide a technique for improving the utilization efficiency of a filter in a gas generator including the filter.SOLUTION: A gas generator includes: a housing; an ignition part arranged in the housing; a gas generating agent stored in a combustion chamber in the housing and generating combustion gas by the operation of the ignition part; a discharge hole disposed in the housing and discharging the combustion gas generated in the housing to the outside; and a filter arranged between the discharge hole and the gas generating agent. The filter is such that: at least an outer peripheral portion extending in an axial direction on one edge face in the axial direction is connected to an internal wall surface of the housing so as to surround the periphery of the discharge hole; a portion as at least a part of an outer peripheral surface existing around a shaft, extending to the overall periphery is an inflow portion of the combustion gas; and the inflow portion is arranged in communication with the combustion chamber.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a gas generator. [Background technology]

[0002] Conventionally, gas generators have been widely used in which a gas generating agent is filled into a combustion chamber formed in a housing, the gas generating agent is combusted by an igniter to generate combustion gas, and the combustion gas is discharged to the outside through a gas discharge hole provided in the housing. In addition, in such gas generators, a cylindrical filter may be disposed between the combustion chamber and the gas discharge hole to cool the generated combustion gas and collect residue.

[0003] Patent Document 1 discloses a gas generator including an ignition material arranged to generate gas, a subassembly formed from a first component and a second component fixed by friction welding, a third component fixed to the first component or the second component by friction welding, and a cylindrical filter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] US Patent Application Publication No. 2019 / 001917 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-mentioned gas generator is configured so that combustion gas flows from the inside to the outside of a cylindrical filter. As the combustion gas passes through the filter, combustion residue is filtered out, so the amount of combustion residue contained (hereinafter also referred to as the contained residue amount) is high on the inlet side of the filter and low on the outlet side. Therefore, in a configuration in which combustion gas flows from the inner peripheral surface to the outer peripheral surface of a cylindrical filter, the contained residue amount is high when the combustion gas flows into the inner peripheral surface, which is narrower than the outer peripheral surface, and the contained residue amount is low when the combustion gas passes through the relatively wide outer peripheral surface, so the filter is not used efficiently, and a technology to improve the utilization efficiency of the filter is needed.

[0006] The technology of the present disclosure has been made in consideration of the above-described circumstances, and its purpose is to provide a technology for improving the utilization efficiency of a filter in a gas generator. [Means for solving the problem]

[0007] In order to solve the above problems, the technology of the present disclosure employs the following configuration. That is, the gas generator of the present disclosure comprises: Housing and an ignition unit disposed within the housing; a gas generating agent accommodated in a combustion chamber within the housing and configured to generate combustion gas upon activation of the ignition unit; a discharge hole provided in the housing for discharging the combustion gas generated within the housing to the outside; a filter disposed between the discharge hole and the gas generating agent; Equipped with The filter extends in the axial direction, and at least the outer peripheral portion of one end face in the axial direction is connected to the inner wall surface of the housing so as to surround the discharge hole, and at least a portion of the outer peripheral surface around the axis, which extends around the entire circumference, is used as an inflow portion for the combustion gas, and the inflow portion is arranged in communication with the combustion chamber.

[0008] The gas generator of the present disclosure further comprises, within the housing, a partition member that separates the combustion chamber in which the gas generating agent is accommodated and a filter chamber in which the filter is disposed, the partition member having a communication hole in a part thereof that communicates the combustion chamber with the filter chamber, A second end face of the filter opposite to a first end face connected to the inner wall surface of the housing in the axial direction may be connected to the partition member.

[0009] In the gas generator of the present disclosure, the housing includes a cylindrical peripheral wall portion extending along the axial direction, a first wall portion closing one end of the cylindrical peripheral wall portion, and a second wall portion closing the other end, The communication hole may be formed in the first wall portion in a direction that allows the combustion gas to be discharged in a direction perpendicular to the first wall portion.

[0010] In the gas generator of the present disclosure, the housing includes a cylindrical peripheral wall portion extending along the axial direction, a first wall portion in which the discharge hole is formed and which closes one end of the cylindrical peripheral wall portion, and a second wall portion which closes the other end, A groove is provided on the inner surface of the first wall portion along the circumferential direction, The communication hole may be provided at a position where the combustion gas is discharged toward the groove portion.

[0011] In the gas generator of the present disclosure, the housing includes a cylindrical peripheral wall portion extending along the axial direction, a first wall portion in which the discharge hole is formed and which closes one end of the cylindrical peripheral wall portion, and a second wall portion which closes the other end, A portion of the partition member that is not connected to the filter may be formed to protrude toward the first wall portion of the housing, relative to a portion of the partition member that is connected to the filter.

[0012] In the gas generator of the present disclosure, the housing includes a cylindrical peripheral wall portion, The communication hole may be formed in a direction that allows the combustion gas to be discharged toward the peripheral wall portion.

[0013] In the gas generator of the present disclosure, the filter may be formed in a cylindrical shape.

[0014] In the gas generator of the present disclosure, the housing includes a cylindrical peripheral wall portion extending along the axial direction, a first wall portion closing one end of the cylindrical peripheral wall portion, and a second wall portion closing the other end, One end surface of the filter in the axial direction may be connected to the first wall portion, and the other end surface may be connected to the second wall portion. [Effects of the Invention]

[0015] According to the present disclosure, in a gas generator equipped with a filter, the utilization efficiency of the filter can be improved. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is an axial cross-sectional view schematically showing the internal structure along the central axis of a gas generator according to a first embodiment. [Figure 2] FIG. 2 is a diagram illustrating the configuration of a filter. [Figure 3] FIG. 3 is a plan view showing an example of a layer structure of a filter. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Figure 5] FIG. 5 is an axial cross-sectional view of a gas generator according to the second embodiment. [Figure 6] FIG. 6 is a view showing the lower surface of the partition member. [Figure 7] FIG. 7 is an axial cross-sectional view of a gas generator according to the third embodiment. [Figure 8] FIG. 8 is an axial cross-sectional view of a gas generator according to the fourth embodiment. [Figure 9] FIG. 9 is an axial cross-sectional view of a gas generator according to a fifth embodiment. [Figure 10] FIG. 10 is a plan view showing the layer structure of the filter according to the fifth embodiment. [Figure 11] FIG. 11 is a cross-sectional view taken along the line BB in FIG. [Figure 12] FIG. 12 is an axial cross-sectional view of a gas generator according to the sixth embodiment. [Figure 13] FIG. 13 is an axial cross-sectional view schematically showing the internal structure along the central axis of a gas generator according to the seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, a gas generator according to an embodiment of the present disclosure will be described with reference to the drawings. Note that each configuration and combination thereof in each embodiment is an example, and addition, omission, substitution, and other modifications of configurations are possible as appropriate within the scope of the gist of the present invention. The present invention is not limited to the embodiments, but is limited only by the claims.

[0018] First Embodiment FIG. 1 is an axial cross-sectional view roughly showing the internal structure of gas generator 100 taken along central axis C of gas generator 100 according to the first embodiment. Hereinafter, a cross-section of gas generator 100 taken along central axis C, as shown in FIG. 1, may be referred to as a "longitudinal cross-section" of gas generator 100. Furthermore, the direction along central axis C of gas generator 100 will be referred to as the "vertical direction" or "axial direction" of gas generator 100, and of these, one side (the upper side of FIG. 1) will be referred to as the "upper side" and the other side (the lower side of FIG. 1) will be referred to as the "lower side". under The upper side (the side facing upward) may be referred to as the "lower side". These directions are examples for explaining the present embodiment, and the arrangement of the gas generator 100 is not limited to these. FIG. 1 shows the state before the gas generator 100 is activated. The gas generator 100 is, for example, an airbag gas generator that supplies gas to an airbag for inflating and deploying the airbag.

[0019] [Overall configuration] As shown in FIG. 1 , gas generator 100 includes an ignition device 7, an inner cylindrical member 5, a filter 6, a partition member 8, a transfer charge 110, a gas generating agent 120, and a housing 1 that accommodates these elements. Gas generator 100 of the present embodiment is configured as a so-called single-type gas generator that includes only one ignition device. However, the present invention is not limited to this, and gas generator 100 may be configured to include a plurality of ignition devices. Gas generator 100 is configured so that, when igniter 71 included in ignition device 7 is activated, gas generating agent 120 is combusted and the resulting combustion product, combustion gas, is released from gas discharge hole 11 formed in housing 1. Each component of gas generator 100 will be described below.

[0020] [housing] The housing 1 is a member that accommodates an inner cylindrical member 5, a filter 6, an ignition device 7, a partition member 8, a transfer charge 110, and a gas generating agent 120. The housing 1 includes an upper container 2 and a lower container 3, each of which is made of metal and formed into a substantially cylindrical shape with a bottom, and the upper container 2 and the lower container 3 are joined with their open ends facing each other, thereby forming a short cylindrical shape with both axial ends closed. The upper container 2 and the lower container 3 define a combustion chamber 10 and constitute a container 20 inside which the gas generating agent 120 and the like are placed. The housing 1 also includes an outer shell member 4 that is fitted onto the gas discharge side of the container 20, which in this example is the upper side.

[0021] The upper vessel 2 has a cylindrical upper peripheral wall 21 and a top plate 22 that closes the upper end of the upper peripheral wall 21, forming an internal space. An opening of the upper vessel 2 is formed at the lower end of this internal space. The lower vessel 3 has a cylindrical lower peripheral wall 31 and a bottom plate 32 that closes the lower end of the lower peripheral wall 31 and to which the ignition device 7 is fixed, forming an internal space. An opening of the lower vessel 3 is formed at the upper end of this internal space.

[0022] The joint 23 at the open end of the upper vessel 2 and the joint 33 at the open end of the lower vessel 3 These upper and lower containers 2 and 3 are overlapped and joined by welding or the like to form a short cylindrical container 20 with both axial ends closed. The upper peripheral wall 21 of the upper container 2 and the lower peripheral wall 31 of the lower container 3 form the peripheral wall 12 of the container 20. In other words, the container 20 is composed of a cylindrical peripheral wall 12, a top plate 22 provided on one end of the peripheral wall 12, and a bottom plate 32 provided on the other end of the peripheral wall 12. The top plate 22 corresponds to the "first wall" according to the present disclosure. The bottom plate 32 corresponds to the "second wall" according to the present disclosure.

[0023] The top plate 22 of the container 20 is provided with a discharge hole 25 that penetrates from the inside to the outside of the container 20 and discharges combustion gas generated inside the container 20 to the outside. The position of the discharge hole 25 is not particularly limited, but in this embodiment, it is provided in the center of the top plate 22 when viewed from above. In other words, the discharge hole 25 is formed concentrically with the peripheral wall 12.

[0024] The ignition device 7 and the inner cylinder member 5 are provided inside the lower container 3, and the lower end of the inner cylinder member 5 is joined to the bottom plate portion 32 of the lower container 3. The inner cylinder member 5 is a cylindrical member that extends from the bottom plate portion 32 toward the top plate portion 22 so as to surround the ignition device 7.

[0025] The inner cylindrical member 5 is disposed concentrically with the peripheral wall portion 12, with its inner space serving as a transfer chamber 50 and its outer space serving as a combustion chamber 10. A roughly disk-shaped partition member 8 is provided on the upper side of the inner cylindrical member 5 to define the transfer chamber 50 and the upper surfaces of the combustion chamber 10. The partition member 8 also defines the combustion chamber 10 and transfer chamber 50 on the lower side, and the filter chamber 60 on the upper side, within the container 20. A plurality of communication holes 81 are provided near the outer edge of the partition member 8, connecting the combustion chamber 10 and the filter chamber 60. The number and arrangement of the communication holes 81 are not particularly limited, but in this embodiment, a plurality of communication holes 81 are provided in the radial direction of the partition member 8, and are also provided at equal intervals along the circumferential direction of the partition member 8. Furthermore, the communication holes 81 are drilled along the axial direction of the housing 1 and are oriented to discharge the combustion gas in a direction perpendicular to the extension direction of the top plate portion 22. That is, the communication holes 81 in this embodiment are formed in a direction along the central axis C. Furthermore, even when the top plate portion 22 is spherical, the discharge direction of the combustion gas may be a direction along the central axis C or a direction perpendicular to the tangent to the spherical surface (radial direction).

[0026] An ignition device 7 is disposed in a transfer chamber 50 inside the inner cylindrical member 5, and a transfer charge 110 is filled around the ignition device 7. A combustion chamber 10 outside the inner cylindrical member 5 is filled with a gas generating agent 120. The inner cylindrical member 5 has a plurality of communication holes 52 formed along the circumferential direction, which communicate between the transfer chamber 50, which is its inner space, and the combustion chamber 10, which is its outer space. Before the ignition device 7 is activated, the communication holes 52 are closed with sealing tape (not shown). When the ignition device 7 is activated, the sealing tape is ruptured by the pressure of the combustion gas, and the transfer chamber 50 and the combustion chamber 10 communicate with each other. Note that the communication holes 52 need not be closed with sealing tape as long as they communicate between the inside and outside of the transfer chamber 50 at least when the ignition device 7 is activated.

[0027] A filter 6 is disposed in a filter chamber 60 within the container 20. The shape of the filter 6 is not particularly limited, and may be, for example, cylindrical or columnar. The filter 6 in this embodiment is cylindrical. Furthermore, the filter 6 in this embodiment is disposed in the center of the filter chamber 60 so as to cover the discharge hole 25, but is not limited thereto and may be disposed in any position between the discharge hole 25 and the gas generating agent 120 through which the combustion gas passes. In other words, the communication hole 25 is formed within a projected area of ​​the cross-sectional shape of the filter 6 perpendicular to the central axis C.

[0028] The filter 6 has an upper surface 61 in contact with the top plate 22 of the container 20 and a lower surface 63 in contact with the upper surface of the partition member 8, and is sandwiched between the top plate 22 and the partition member 8. A recess 82 having substantially the same shape as the lower part of the filter 6 is provided on the upper surface of the partition member 8, and the lower part of the filter 6 is fitted into the recess 82 to position it.

[0029] Container 20 is filled with pressurized inert gas (hereinafter also referred to as pressurized gas), and discharge hole 25 is closed by rupture disc 26. Furthermore, a cup-shaped seal member 53 is arranged so as to cover the periphery of ignition device 7, thereby maintaining airtightness at the opening of bottom plate portion 32 to which ignition device 7 is attached. Seal member 53 is made of, for example, metal, and is joined to bottom plate portion 32 by welding or the like. Seal member 53 has sufficient rigidity to withstand the pressure of the inert gas, and is configured to be ruptured by activation of ignition device 7. Here, examples of the inert gas include argon, helium, or a mixture thereof. Gas generator 100 of the present embodiment is a hybrid type that emits pressurized gas and combustion gas when activated.

[0030] The outer shell member 4 attached to the gas discharge side of the container 20 has a cylindrical peripheral wall portion 41, a top plate portion 42 closing the upper end of the peripheral wall portion 41, and a flange portion 43 extending radially from the lower end of the peripheral wall portion 41. The outer shell member 4 fits over the top of the container 20 and is joined to the outer surface of the peripheral wall portion 41. When joined to the container 20 in this manner, the outer shell member 4 forms a discharge side space 44 between itself and the top plate portion 22 of the container 20, which serves as a discharge path for combustion gas. A plurality of gas discharge holes 11 connecting the discharge side space 44 to the outside space are formed in the peripheral wall portion 41 of the outer shell member 4, lined up along the circumferential direction.

[0031] [Ignition device] As shown in FIG. 1 , the ignition device 7 includes an igniter 71 and a mounting member 72, and is fixed to the bottom plate portion 32 of the lower container 3. The ignition device 7 corresponds to the "ignition unit" according to the present disclosure. The igniter 71 has a metal cup body 711 that houses an ignition charge, and a pair of current-carrying pins 712, 713 for receiving a current supply from the outside. The igniter 71 is activated by an ignition current supplied to the pair of current-carrying pins 712, 713, causing the ignition charge to burn and releasing the combustion products to the outside of the cup body 711.

[0032] Mounting member 72 is a member that is interposed between igniter 71 and bottom plate portion 32, thereby fixing igniter 71 to bottom plate portion 32. Mounting member 72 includes a resin that covers the lower part of igniter 71, and forms a connector insertion space into which a connector (not shown) that supplies power from an external power source to a pair of current-carrying pins 712, 713 can be inserted. Note that the fixing of igniter 71 to bottom plate portion 32 and the relationship between mounting member 72 and bottom plate portion 32 are not limited to those shown in FIG. 1, and known techniques can be used.

[0033] [filter] 2 is a diagram showing the configuration of the filter 6. The filter 6 is a cylindrical member made of a metal material and has fine pores that filter residue in the combustion gas and cool the combustion gas by allowing the combustion gas to pass through. The filter 6 extends in the axial direction, and at least the outer circumferential portion of a first end face (top face) 61 in the axial direction is connected to the top plate portion 22 so as to surround the discharge hole 25. At least a portion of the outer circumferential face 62 around the axis, which extends over the entire circumference, serves as an inflow portion for the combustion gas, and the filter 6 is disposed so that this inflow portion communicates with the combustion chamber 10 during operation. As a result, when combustion gas is released from the combustion chamber 10 during operation, the combustion gas flows in from the outer circumferential face 62 of the filter 6 and is discharged from the center of the top face 61 to the discharge hole 25. At this time, the upper surface 61 of the filter 6 abuts against the top plate portion 22, and the opposite lower surface (second end surface) 63 abuts against the recess 82 of the partition wall member 8, so that the combustion gas is prevented from flowing between the upper surface 61 and the top plate portion 22 or between the lower surface 63 and the partition wall member 8, i.e., so-called "short pass." Note that sealing means may be provided between the upper surface 61 and the top plate portion 22, between the lower surface 63 and the partition wall member 8, or both.

[0034] The filter 6 according to this example is formed by stacking annular metal plates with a large number of holes formed therein in the radial direction. For example, the filter 6 may be formed by stacking cylindrical metal plates concentrically, or by winding metal plates spirally in a plan view and stacking them in the radial direction. Alternatively, the filter 6 may be formed by stacking perforated metal plates formed into a disk shape in the axial direction. Examples of perforated metal plates that can be used to form the filter 6 include expanded metal, lath metal, punched metal, and wire mesh. In FIG. 2 , reference numeral 62 denotes the outer circumferential surface of the filter 6. Since the filter 6 has a plurality of holes formed therein, the combustion gas from the gas generating agent 120 disposed in the combustion chamber 10 can pass through the filter 6. The filter 6 filters the combustion gas by collecting combustion residues contained in the combustion gas. In addition to the above-described function of filtering the combustion gas, the filter 6 also functions to cool the combustion gas by removing heat from the combustion gas as it passes through the filter 6. The filter 6 may also be a compression-molded filter as disclosed in Japanese Patent Application Laid-Open No. 10-119705 or a wound filter in which metal wire is wound in multiple layers as disclosed in Japanese Patent Application Laid-Open No. 2005-193138.

[0035] Fig. 3 is a plan view showing an example of the layer configuration of filter 6, and Fig. 4 is a cross-sectional view taken along line AA in Fig. 3. Filter 6 may include multiple layers in the radial direction, with each layer having a different specification. For example, filter 6 may be configured such that the density of the inner layer is higher (the aperture ratio is smaller) than the outer layer. Filter 6 in Figs. 3 and 4 includes three layers: an inner portion 65, a middle portion 66, and an outer portion 67, with the middle portion 66 having a lower density than the inner portion 65, and the outer portion 67 having a lower density than the middle portion 66.

[0036] [Transfer powder] As the enhancer charge 110, in addition to known black powder, a gas generant having good ignition properties and a higher combustion temperature than the gas generant 120 can be used. The combustion temperature of the enhancer charge 110 can be set in the range of 1700 to 3000°C. As such an enhancer charge 110, known materials containing, for example, nitroguanidine (34% by weight) and strontium nitrate (56% by weight) can be used. Furthermore, the enhancer charge 110 can be in various shapes, such as granular, pellet, cylindrical, or disk shape.

[0037] [Gas Generator] A gas generating agent with a relatively low combustion temperature can be used as the gas generating agent 120. The combustion temperature of the gas generating agent 120 can be set in the range of 1000 to 1700°C. As such a gas generating agent 120, for example, a known agent containing guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), a binder, and an additive can be used. Furthermore, the gas generating agent 120 can be in various shapes, such as granular, pellet, cylindrical, or disk shape.

[0038] [Operation] The operation of gas generator 100 according to the first embodiment will now be described. First, a description will be given with reference to FIG. 1 . When a sensor (not shown) detects an impact, an ignition current is supplied to a pair of conductive pins 712, 713, and igniter 71 is activated. That is, the ignition charge housed in cup body 711 of igniter 71 burns, and the resulting combustion products, such as flame and high-temperature gas, rupture cup body 711 and are released to the outside of cup body 711. This causes transfer charge 110 housed in transfer chamber 50 to burn, generating combustion gas. The combustion gas of transfer charge 110 breaks the sealing tape that had been closing communicating hole 52 and is released from communicating hole 52 to the outside of transfer chamber 50. Then, the combustion gas of transfer charge 110 comes into contact with gas generant 120, igniting gas generant 120. As gas generant 120 burns, high-temperature, high-pressure combustion gas is generated in combustion chamber 10. When the generation of combustion gas starts in this way and the pressure inside the container 20 increases, the rupture disc 26 blocking the discharge hole 25 ruptures, and the combustion gas is discharged from the discharge hole 25 together with the pressurized gas inside the container 20. At this time, the combustion gas passes through the filter 6, whereby the combustion gas is cooled and combustion residue is collected. The pressurized gas and combustion gas that have passed through the filter 6 and been discharged from the discharge hole 25 to the discharge side space 44 are deflected in the radial direction of the housing 1 by hitting the top plate portion 42 of the outer shell member 4, and are released to the outside of the housing 1 from the gas discharge hole 11. Then, the pressurized gas The gas and combustion gases are released to the outside of the housing 1 and then flow into an airbag (not shown), which inflates the airbag to form a cushion between the occupant and the rigid structure, protecting the occupant from impact.

[0039] [Actions and Effects] In gas generator 100 of the present embodiment, at least the outer peripheral portion of one end face 61 of filter 6 is connected to the inner wall surface of top plate portion 22 so as to surround the periphery of discharge hole 25, and outer peripheral surface 62 is disposed in communication with combustion chamber 10. As a result, combustion gas passes through outer peripheral surface 62 of filter 6 at the initial stage of inflow, when the amount of contained combustion residue (hereinafter also referred to as contained residue amount) is large, and passes through the inner portion as it is filtered and the amount of contained residue decreases. In other words, as the combustion gas travels inward from the inflow portion formed over the entire circumferential direction of outer peripheral surface 62 of filter 6, the amount of contained residue is filtered and decreases, the combustion gas temperature also decreases, and the cross-sectional area in the filter radial direction with which the combustion gas comes into contact also gradually decreases. In other words, a filter contact area corresponding to the contained residue amount and gas temperature is provided. Therefore, the utilization efficiency of filter 6 can be improved, and the performance of gas generator 100 can be improved. Furthermore, by improving the utilization efficiency of filter 6, the same filter performance as conventional can be achieved with a smaller filter 6, allowing gas generator 100 to be made more compact.

[0040] Furthermore, in gas generator 100 of the present embodiment, filter 6 may be configured to include a plurality of layers in the radial direction, with the density of the inner layers being higher than that of the outer layers. This can further improve the utilization efficiency of filter 6.

[0041] Furthermore, in gas generator 100 of the present embodiment, communication holes 81 of partition member 8 are formed in a direction that releases combustion gas in a direction perpendicular to the extension direction of top plate portion 22. This causes the combustion gas generated in combustion chamber 10 to first hit top plate portion 22, causing large residues and highly adhesive residues to adhere to top plate portion 22 before flowing into filter 6, thereby further improving the utilization efficiency of filter 6.

[0042] Furthermore, in gas generator 100 of the present embodiment, upper surface 61 of filter 6 abuts against top plate portion 22, and lower surface 63 of filter 6 abuts against recess 82 of partition member 8. This prevents combustion gas from flowing between upper surface 61 and top plate portion 22 or between lower surface 63 and partition member 8, a so-called "short pass," and can improve the utilization efficiency of filter 6. Note that in the first embodiment, a gap may be formed between lower surface 63 and partition member 8, as long as short pass between upper surface 61 of filter 6 and top plate portion 22 is prevented.

[0043] Second Embodiment Fig. 5 is an axial cross-sectional view of gas generator 200 according to the second embodiment, and Fig. 6 is a view showing the underside of partition member 8. Fig. 5 shows a state before gas generator 200 is activated. This embodiment differs from the first embodiment described above in the configuration of top plate portion 22A, but the other configurations are the same. For this reason, elements similar to those in the first embodiment are given the same reference numerals, and repeated description will be omitted.

[0044] 5 and 6, the upper vessel 2 of this embodiment has a cylindrical upper peripheral wall portion 21 and a top plate portion 22A that closes the upper end of the upper peripheral wall portion 21. A groove portion 222 is provided along the circumferential direction on the lower surface 221 side of the top plate portion 22A. The communication hole 81 of the partition member 8 is provided at a position that allows the combustion gas to be released toward the groove portion 222. The communication hole 81 of this embodiment is formed in the axial direction directly below the groove portion 222, and releases the combustion gas toward the groove portion 222.

[0045] As described above, according to this embodiment, the combustion gas generated in the combustion chamber 10 is discharged toward the grooves 222, where it is retained before flowing into the filter 6. As a result, large residues and highly adhesive residues in the combustion gas are removed by the grooves 222, improving the utilization efficiency of the filter 6. The surface of the grooves 222 may be further uneven to increase the contact area with the combustion gas.

[0046] Third Embodiment Fig. 7 is an axial cross-sectional view of gas generator 300 according to the third embodiment. Fig. 7 shows gas generator 300 in a state prior to activation. This embodiment differs from the first embodiment described above in the configuration of partition member 8A, but the other configurations are the same. For this reason, elements similar to those in the first embodiment are given the same reference numerals, and repeated description will be omitted.

[0047] As shown in Fig. 7, partition member 8A of the present embodiment is formed so that an outer region 84 not connected to filter 6 protrudes toward top plate portion 22 of housing 1 relative to a central region 83 connected to filter 6. In the example of Fig. 7, outer region 84 is formed in a tapered shape so that it is positioned higher as it moves from the inside to the outside in the radial direction. In other words, combustion chamber 10 is provided so as to protrude toward filter chamber 60. For this reason, in gas generator 300 of the present embodiment, lower circumferential wall portion 31 of lower vessel 3 is extended upward to match partition member 8A, and compared to the first embodiment, the joint between upper vessel 2 and lower vessel 3 is formed closer to top plate portion 22 than partition member 8A.

[0048] As described above, according to the present embodiment, the combustion chamber 10 is formed larger than that of the gas generator 100 of the first embodiment, and therefore the amount of gas generating agent 120 and pressurized gas filled can be increased, thereby improving the performance of the gas generator 300.

[0049] <Fourth embodiment> Fig. 8 is an axial cross-sectional view of gas generator 400 according to the fourth embodiment. Fig. 8 shows a state before activation of gas generator 400. This embodiment differs from the third embodiment described above in the configuration of partition member 8B, but the other configurations are the same. For this reason, elements similar to those in the third embodiment are given the same reference numerals, and repeated description will be omitted.

[0050] 8, the partition member 8B of this embodiment is tapered such that an outer portion 85 not connected to the filter 6 is positioned lower from the inside to the outside in the radial direction relative to a central portion 83 connected to the filter 6. Also, the communication holes 81B of the partition member 8B are positioned more outer (toward the peripheral wall 12) as they move from the combustion chamber 10 side to the filter chamber 60 side. That is, the communication holes 81B of this embodiment are oriented to release combustion gas toward the peripheral wall 12.

[0051] As described above, according to this embodiment, the combustion gas generated in the combustion chamber 10 is discharged toward the peripheral wall portion 12, and after hitting the peripheral wall portion 12, flows into the filter 6. As a result, large residues and highly adhesive residues in the combustion gas adhere to the peripheral wall portion 12 and are removed, thereby improving the utilization efficiency of the filter 6.

[0052] Fifth Embodiment Fig. 9 is an axial cross-sectional view of gas generator 500 according to the fifth embodiment, Fig. 10 is a plan view showing the layer configuration of filter 6A according to the fifth embodiment, and Fig. 11 is a cross-sectional view taken along line BB of Fig. 10. Fig. 9 shows gas generator 500 in a state prior to activation. This embodiment differs from the first embodiment described above in the configuration of filter 6A, but the other configurations are the same. For this reason, elements similar to those in the first embodiment will be given the same reference numerals, and repeated description will be omitted.

[0053] As shown in Figure 9, the filter 6A of this embodiment is formed in a cylindrical shape. AOne axial end face (upper face) 61A of the filter 6A is connected to the top plate portion 22 so as to surround the discharge hole 25, and the other axial end face (lower face) 63A is connected to the partition member 8. That is, the filter 6A has a through hole in the radial center portion from the upper face 61A to the lower face 63A, and the discharge hole 25 is formed in the area facing the through hole. The filter 6A may also have multiple layers in the radial direction, with each layer having different specifications. For example, the filter 6A has two layers, an inner portion 66A and an outer portion 67A, with the density of the outer portion 67A being lower than that of the inner portion 66A. The number of layers is not limited to this and may be set arbitrarily.

[0054] As described above, according to this embodiment, the combustion gas generated in the combustion chamber 10 is configured to pass through the filter 6A from the outside to the inside. This improves the utilization efficiency of the filter 6. Note that, in this embodiment, the configuration other than the filter 6A is the same as in the first embodiment, but is not limited to this and may be configured similarly to the second to fourth embodiments.

[0055] Sixth Embodiment Fig. 12 is an axial cross-sectional view of gas generator 600 according to the sixth embodiment. Fig. 12 shows gas generator 600 in a state prior to activation. This embodiment differs from the previously described fifth embodiment in that it is a pyrotechnic type that does not use pressurized gas, but the other configurations are the same. For this reason, elements similar to those in the fifth embodiment will be denoted by the same reference numerals, and repeated description will be omitted.

[0056] In this embodiment, the container 20 is not filled with pressurized gas, and the lower end of the discharge hole 25 is closed with a sealing tape 27. That is, the sealing tape 27 is disposed within the internal space of the filter 6A, and is configured so that the sealing tape 27 and the filter 6A do not interfere with each other.

[0057] When the igniter 71 is activated and the transfer charge 110 and gas generating agent 120 are burned to generate combustion gas, the sealing tape blocking the communication hole 52 is torn open, and the combustion gas passes through the filter 6A and is discharged from the discharge hole 25, and is then released to the outside of the housing 1 through the gas discharge hole 11 via the discharge side space 44.

[0058] As described above, according to this embodiment, the combustion gas generated in the combustion chamber 10 passes through the filter 6A from the outside to the inside, thereby improving the utilization efficiency of the filter 6A.

[0059] Seventh Embodiment 13 is an axial cross-sectional view roughly showing the internal structure of gas generator 700 according to the seventh embodiment, taken along central axis C. Elements similar to those in the first embodiment described above are given the same reference numerals, and some description will be omitted. Furthermore, gas generator 700 of the seventh embodiment does not use pressurized gas.

[0060] 13, gas generator 700 includes an ignition device 7, a filter 6B, a gas generating agent 120, and a housing 1 that accommodates these. Gas generator 700 of the present embodiment is configured as a so-called single-type gas generator that includes only one ignition device. However, the present invention is not limited to this, and gas generator 700 may be configured to include a plurality of ignition devices.

[0061] The housing 1 is a member that accommodates the filter 6B, the ignition device 7, and the gas generating agent 120. The housing 1 includes an upper container 2 and a lower container 3, each of which is made of metal and formed into a substantially cylindrical shape with a bottom, and the upper container 2 and the lower container 3 are joined together with their open ends facing each other. The upper and lower containers 2 and 3 are joined together to form a short cylindrical shape with both axial ends closed. The upper and lower containers 2 and 3 define a combustion chamber 10A and constitute a container 20 in which a gas generating agent 120 and the like are placed. The housing 1 also includes an outer shell member 4 fitted over the gas discharge side of the container 20, i.e., the upper side in this example.

[0062] The top plate 22 of the container 20 is provided with a discharge hole 25 that penetrates from the inside to the outside of the container 20 and discharges combustion gas generated within the container 20 to the outside.

[0063] A cylindrical filter 6B is provided inside the container 20, dividing the interior space of the container 20 into an inner space and an outer space, with the outer space being the combustion chamber 10A. A through hole is formed in the center of the filter 6B in the radial direction from the upper surface 61B to the lower surface 63B, and a discharge hole 25 is formed so as to face the area (internal space) formed by the through hole.

[0064] An ignition device 7 is disposed in the combustion chamber 10A in the lower container 3, and a gas generating agent 120 is filled around the ignition device 7. The filter 6B is a cylindrical member formed from a metal material, and its upper surface 61B contacts the top plate portion 22 so as to surround the discharge hole 25, and its lower surface 63B contacts the bottom plate portion 32, and it is sandwiched between the top plate portion 22 and the bottom plate portion 32.

[0065] A sealing tape 27 is provided at the center of the inner surface of the top plate portion 22 so as to cover the drain hole 25 and close the drain hole 25. In other words, the sealing tape 27 is arranged within the internal space of the filter 6B so that the sealing tape 27 and the filter 6B do not interfere with each other.

[0066] When the igniter 71 is activated, the ignition charge housed in the cup body 711 of the igniter 71 burns, and the resulting combustion products, such as flame and high-temperature gas, are discharged to the outside of the cup body 711. This causes the gas generating agent 120 housed in the combustion chamber 10A to burn, generating high-temperature, high-pressure combustion gas. This increases the pressure inside the container 20, causing the sealing tape 27 blocking the discharge hole 25 to rupture, and the combustion gas is discharged from the discharge hole 25 via the filter 6B. As the combustion gas passes through the filter 6B, the combustion gas is cooled and combustion residue is collected. The pressurized gas and combustion gas discharged from the discharge hole 25 to the discharge-side space 44 strike the top plate portion 42 of the outer shell member 4, deflected in the radial direction of the housing 1, and discharged to the outside of the housing 1 through the gas discharge hole 11. After being discharged to the outside of the housing 1, the pressurized gas and combustion gas flow into the airbag (not shown). This allows the airbag to inflate, creating a cushion between the occupant and the rigid structure, protecting the occupant from impact.

[0067] In gas generator 700 of the present embodiment, one end surface 61B of filter 6B is connected to the inner wall surface of top plate portion 22 so as to surround discharge hole 25, and outer peripheral surface 62B is connected to combustion chamber 10. A and is arranged in communication with the filter 6B. As a result, the combustion gas passes through the outer peripheral surface 62B of the filter 6B at the initial stage of inflow when the amount of contained residue is large, and passes toward the inner peripheral surface 68 of the filter 6B as it is filtered and the amount of contained residue decreases. In other words, as the combustion gas travels from the inflow portion formed over the entire circumferential direction of the outer peripheral surface 62B of the filter 6B to the inner peripheral surface 68, the amount of contained residue is filtered and decreases, the combustion gas temperature also decreases, and the cross-sectional area in the filter radial direction with which the combustion gas comes into contact also gradually decreases. In other words, a contact area of ​​the filter corresponding to the amount of contained residue and the gas temperature is provided. This makes it possible to improve the utilization efficiency of the filter 6B, and to improve the performance of the gas generator 700.

[0068] Furthermore, in gas generator 700 of the present embodiment, filter 6B is disposed such that upper surface 61B abuts against top plate portion 22 and lower surface 63B of filter 6B abuts against bottom plate portion 32. This allows combustion gas to flow through upper surface 61 Band the top plate portion 22, and the lower surface 63 B and the bottom plate portion 32, so-called "short pass" is prevented, and the filter 6 B 9, 12 and 13, as long as a short path between upper surfaces 61A, 61B of the filter and top plate portion 22 is prevented, the through holes of the filter do not have to pass through to lower surfaces 63A, 63B, and a member can be interposed between lower surfaces 63A, 63B and partition member 8 or bottom plate portion 32, so that the filter can be disposed away from partition member 8 or bottom plate portion 32.

[0069] <Other> Although preferred embodiments of the present disclosure have been described above, each aspect disclosed in this specification can be combined with any other feature disclosed in this specification. [Explanation of symbols]

[0070] 1: Housing 10: Combustion chamber 100~700: Gas generator 10A: Combustion chamber 11: Gas exhaust hole 110: Transfer Charge 12: Peripheral wall 120: Gas Generator 2: Upper vessel 20: Container 21: Upper peripheral wall part 22: Top plate 221: Bottom surface 222: Groove 22A: Top plate 23: Joint 25: Exhaust hole 26: Rupture disc 27: Sealing tape 3: Lower vessel 31: Lower peripheral wall part 32: Bottom plate part 33: Joint 4: Outer shell 41: Peripheral wall part 42: Top plate 43: Flange 44: Discharge side space 5: Inner cylinder member 50: Fire transmission room 52: Communication hole 6,6A,6B: Filter 60: Filter chamber 7: Ignition device 8: Partition wall member 81,81B: Communication hole 82: Recess

Claims

1. Housing and an ignition unit disposed within the housing; a gas generating agent accommodated in a combustion chamber within the housing and configured to generate combustion gas upon activation of the ignition unit; a discharge hole provided in the housing for discharging the combustion gas generated within the housing to the outside; a filter disposed between the discharge hole and the gas generating agent; Equipped with The filter extends in the axial direction, and at least an outer peripheral portion of one end face in the axial direction is connected to the inner wall surface of the housing so as to surround the periphery of the discharge hole, and at least a portion of the outer peripheral surface existing around the axis, which is a region extending over the entire circumference, is an inflow portion of the combustion gas, and the inflow portion is arranged in communication with the combustion chamber, and is formed so that the density of the outer portion is lower than that of the inner portion in a radial direction perpendicular to the axial direction. Gas generator.

2. the housing further includes a partition member that separates the combustion chamber in which the gas generating agent is accommodated and a filter chamber in which the filter is disposed, the partition member having a communication hole in a part thereof that communicates the combustion chamber with the filter chamber, a second end surface of the filter opposite to a first end surface connected to the inner wall surface of the housing in the axial direction thereof is connected to the partition member; 2. The gas generator according to claim 1.

3. the housing includes a cylindrical peripheral wall portion extending along the axial direction, a first wall portion closing one end of the cylindrical peripheral wall portion, and a second wall portion closing the other end of the cylindrical peripheral wall portion, The communication hole is formed in the first wall portion in a direction that discharges the combustion gas in a direction perpendicular to the first wall portion.

3. The gas generator according to claim 2.

4. The housing has a cylindrical peripheral wall portion extending along the axial direction and a discharge hole formed therein. The cylindrical peripheral wall portion has a first wall portion that closes one end thereof and a second wall portion that closes the other end thereof. A groove is provided on the inner surface of the first wall portion along the circumferential direction, The communication hole is provided at a position where the combustion gas is discharged toward the groove portion.

3. The gas generator according to claim 2.

5. A housing, an ignition unit disposed within the housing; a gas generating agent accommodated in a combustion chamber within the housing and configured to generate combustion gas upon activation of the ignition unit; a discharge hole provided in the housing for discharging the combustion gas generated within the housing to the outside; a filter disposed between the discharge hole and the gas generating agent; a partition member that separates the combustion chamber from a filter chamber in which the filter is disposed within the housing, the partition member having a communication hole that communicates the pre-combustion chamber with the filter chamber; Equipped with the filter extends in the axial direction, and at least an outer peripheral portion of one end face in the axial direction is connected to the inner wall surface of the housing so as to surround the periphery of the discharge hole, and at least a portion of the outer peripheral surface existing around the axis, which is a region extending over the entire circumference, serves as an inflow portion for the combustion gas, and the inflow portion is disposed in communication with the combustion chamber, the housing includes a cylindrical peripheral wall portion extending along the axial direction, a first wall portion in which the discharge hole is formed and which closes one end of the cylindrical peripheral wall portion, and a second wall portion which closes the other end of the cylindrical peripheral wall portion, A groove is provided on the inner surface of the first wall portion along the circumferential direction, The communication hole is provided at a position where the combustion gas is discharged toward the groove portion. Gas generator.

6. the housing includes a cylindrical peripheral wall portion extending along the axial direction, a first wall portion in which the discharge hole is formed and which closes one end of the cylindrical peripheral wall portion, and a second wall portion which closes the other end of the cylindrical peripheral wall portion, a portion of the partition member that is not connected to the filter is formed to protrude toward the first wall portion of the housing, relative to a portion of the partition member that is connected to the filter; 3. The gas generator according to claim 2.

7. A housing; an ignition unit disposed within the housing; a gas generating agent accommodated in a combustion chamber within the housing and configured to generate combustion gas upon activation of the ignition unit; a discharge hole provided in the housing for discharging the combustion gas generated within the housing to the outside; a filter disposed between the discharge hole and the gas generating agent; a partition member that separates the combustion chamber from a filter chamber in which the filter is disposed within the housing, the partition member having a communication hole that communicates the pre-combustion chamber with the filter chamber; Equipped with the filter extends in the axial direction, and at least an outer peripheral portion of one end face in the axial direction is connected to the inner wall surface of the housing so as to surround the periphery of the discharge hole, and at least a portion of the outer peripheral surface existing around the axis, which is a region extending over the entire circumference, serves as an inflow portion for the combustion gas, and the inflow portion is disposed in communication with the combustion chamber, the housing includes a cylindrical peripheral wall portion extending along the axial direction, a first wall portion in which the discharge hole is formed and which closes one end of the cylindrical peripheral wall portion, and a second wall portion which closes the other end of the cylindrical peripheral wall portion, In the partition member, a portion not connected to the filter is formed to protrude toward the first wall portion of the housing relative to a portion connected to the filter. Gas generator.

8. the housing has a cylindrical peripheral wall portion, The communication hole is formed in a direction to discharge the combustion gas toward the peripheral wall portion.

3. The gas generator according to claim 2.

9. 9. The gas generator according to claim 1, wherein the filter is formed in a cylindrical shape.

10. the housing includes a cylindrical peripheral wall portion extending along the axial direction, a first wall portion closing one end of the cylindrical peripheral wall portion, and a second wall portion closing the other end of the cylindrical peripheral wall portion, One end surface of the filter in the axial direction is connected to the first wall portion, and the other end surface is connected to the second wall portion.

2. The gas generator according to claim 1.

11. A housing; an ignition unit disposed within the housing; a gas generating agent accommodated in a combustion chamber within the housing and configured to generate combustion gas upon activation of the ignition unit; a discharge hole provided in the housing for discharging the combustion gas generated within the housing to the outside; a filter disposed between the discharge hole and the gas generating agent; Equipped with the filter extends in the axial direction, and at least an outer peripheral portion of one end face in the axial direction is connected to the inner wall surface of the housing so as to surround the periphery of the discharge hole, and at least a portion of the outer peripheral surface existing around the axis, which is a region extending over the entire circumference, serves as an inflow portion for the combustion gas, and the inflow portion is disposed in communication with the combustion chamber, the housing includes a cylindrical peripheral wall portion extending along the axial direction, a first wall portion closing one end of the cylindrical peripheral wall portion, and a second wall portion closing the other end of the cylindrical peripheral wall portion, One end surface of the filter in the axial direction is connected to the first wall portion, and the other end surface is connected to the second wall portion. Gas generator.

12. 8. The gas generator according to claim 5, wherein a second end face of the filter opposite to a first end face connected to the inner wall surface of the housing in the axial direction is connected to the partition member.

Images