Gas generator

Abstract

To provide a gas generator which can reduce output loss of an igniter and can be reduced in size and weight thereof compared to a conventional one.SOLUTION: A gas generator 100 comprises a gas container 10, a tubular member 30, and an igniter 40. The tubular member 30 is a member curving into a substantially L shape, and has a substantially L-shaped passage 31 therein. The tubular member 30 has one end provided adjacent to a mouth 13 and the other end provided with the igniter 40, and a piston body part 32 and a sharp part 33 that constitute a piston in the passage 31, is provided between the one end and the other end. An end part 32a of the piston body part 32 at least on the igniter 40 side functions as a closing member which closes the passage 31 in an initial state, and is integrated with the piston body part 32. During operation, the end part 32a slides and moves to the mouth 13 side together with the piston body part 32, causes the sharp part 33 to collide with an encapsulation part 14, breaks the encapsulation part 14, and discharges a gas from the mouth 13.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gas generator as an occupant protection device mounted on an automobile, etc. In particular, it relates to a gas generator that injects gas from a bottle. [Background technology]

[0002] As an example of a gas generator, Patent Document 1 listed below discloses an inflator comprising: a bottle having a mouth filled with high-pressure gas; a sealing plate that seals the mouth of the bottle; an initiator that generates an explosive wind that serves as the driving force for breaking the sealing plate; and a piston that is accelerated by the explosive wind from the initiator and breaks the sealing plate, and further comprising a curved passage that guides the explosive wind from the initiator to the piston. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-211346 Summary of the Invention [Problem to be solved by the invention]

[0004] For gas generators typified by the above-mentioned patent documents, there is a demand for reducing output loss when the piston is operated by a blast generated by an igniter. The reason for this is that if the output loss can be reduced, for example, the same effects as conventional ones can be achieved even if the output of the igniter is further reduced, and therefore the igniter can be made smaller and lighter, and in turn, the gas generator itself can be made smaller and lighter.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a gas generator that can reduce the output loss of an igniter and can be made smaller and lighter than conventional gas generators. [Means for solving the problem]

[0006] (1) A gas generator of the present invention comprises a gas container having a mouth filled with high-pressure gas, a sealing part sealing the mouth of the gas container, an igniter generating a blast that serves as a driving force for opening the sealing part, a piston that moves toward the mouth of the gas container by the blast of the igniter and breaks and opens the sealing part, and a generally L-shaped piston. It was formed to be curved The gas container has a passage therein, one end of which is adjacent to the opening of the gas container, and the igniter is provided at the other end of the passage. so as to slide along the inner wall from the other end to the one end. and a substantially L-shaped tubular member in which the piston is disposed and which guides the blast wave of the igniter to the piston, wherein the piston has a piston main body, a sharpened portion which is provided at the end of the piston main body on the sealing portion side and adjacent to the mouth of the gas container, and which can break the mouth of the gas container, and a blocking member which is provided at the end of the piston main body on the igniter side and adjacent to the igniter, and which blocks the passage in an initial state.

[0007] (2) the igniter is provided at the other end of the substantially L-shaped passageway, and the substantially L-shaped tubular member has one end adjacent to the mouth of the gas container and the igniter is provided at the other end, and the piston is disposed in the passageway between the one end and the other end, and the blast wave of the igniter is guided to the piston, wherein the piston has a piston main body, a sharpened portion provided at an end of the piston main body on the sealing portion side and adjacent to the mouth of the gas container, the sharpened portion being able to break the mouth of the gas container, and a blocking member provided at an end of the piston main body on the igniter side and adjacent to the igniter, and blocking the passageway in an initial state, The piston body and the closing member are made of hard urethane foam, and the closing member is integrated with the piston body. may be .

[0008] (3) the igniter is provided at the other end of the substantially L-shaped passageway, and the substantially L-shaped tubular member has one end adjacent to the mouth of the gas container and the igniter is provided at the other end, and the piston is disposed in the passageway between the one end and the other end, and the blast wave of the igniter is guided to the piston, wherein the piston has a piston main body, a sharpened portion provided at an end of the piston main body on the sealing portion side and adjacent to the mouth of the gas container, the sharpened portion being able to break the mouth of the gas container, and a blocking member provided at an end of the piston main body on the igniter side and adjacent to the igniter, and blocking the passageway in an initial state, The piston body may be made of a spring, and the blocking member may be a disk-shaped member fixed to an end of the spring on the igniter side.

[0009] (4) In the gas generators of (1) to (3) above, it is preferable that the gas generator further comprises a substantially L-shaped tubular member having one end connected to the tip of the mouth of the gas container and having at the other end a gas outlet for ejecting gas when the mouth of the gas container is ruptured, and that at least a portion of the tubular member where the igniter is provided is provided in the tubular member so as to protrude from the side surface of the one end side of the tubular member, and that the portion of the tubular member other than the portion protruding from the side surface of the one end side of the tubular member is disposed inside the tubular member in a state where a space is formed that allows gas to pass from the mouth of the gas container to the gas outlet. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a gas generator that can reduce the output loss of the igniter and can be made smaller and lighter than before. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2(a) is a schematic perspective view of a gas generator according to an embodiment of the present invention, and FIG. 2(b) is a partial see-through view showing a state in which a gas container has been removed from a cylindrical member of the gas generator of FIG. [Figure 2] 2A and 2B are diagrams for explaining the operation of the gas generator of FIG. 1, in which (a) is a partial cross-sectional schematic diagram showing the initial state and (b) is a diagram showing the gas generator during operation. [Figure 3] 2 is a schematic view showing a configuration of a piston of the gas generator of FIG. 1. FIG. [Figure 4] 1. FIG. 5 is a diagram for explaining the operation of a gas generator according to a modified example of the gas generator of FIG. 1, where (a) is a partial cross-sectional schematic diagram showing the initial state and (b) is a diagram showing the middle of operation. [Figure 5] FIG. 5 is a schematic view showing a configuration of a piston of the gas generator of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] A gas generator 100 according to an embodiment of the present invention will now be described with reference to FIGS.

[0013] As shown in FIG. 1, the gas generator 100 includes a gas container 10, a cylindrical member 20, a tubular member 30, and an igniter 40.

[0014] Gas container 10 is a cylindrical bottle 11 made of metal (iron, steel, etc.), with one end formed with a male thread portion 12. A mouth 13 sealed with a sealing portion 14 is formed at the tip of male thread portion 12. Sealing portion 14 is, for example, a disk-shaped metallic sealing plate (for example, a steel plate with a thickness of 0.2 mm to 0.4 mm), and is attached to mouth 13 by welding or the like. The inside of gas container 10 is filled with an inert gas or the like at high pressure.

[0015] The cylindrical member 20 is a generally L-shaped member made of metal or resin (including composite materials such as fiber-reinforced plastics) and has a first tubular portion 21, one end of which can be connected to the tip of the opening 13 of the gas container 10, and a second tubular portion 22, which is provided at the other end of the first tubular portion 21 at a generally right angle. A generally L-shaped passage 23, formed along the outer shape of the cylindrical member 20, is provided inside the cylindrical member 20 so as to connect the interior of the first tubular portion 21 to the interior of the second tubular portion 22. A female thread portion 24 is formed on the inner wall of one end of the first tubular portion 21, and the male thread portion 12 of the gas container 10 can be threadably engaged with the female thread portion 24. A gas outlet 25 from which gas is ejected is formed at the end of the second tubular portion 22 opposite the first tubular portion 21, allowing gas to be supplied into, for example, an airbag (not shown).

[0016] The tubular member 30 is a tubular member made of metal or resin (including composite materials such as fiber-reinforced plastic) curved into a substantially L-shape, and has an approximately L-shaped passage 31 inside that conforms to the outer shape. The tubular member 30 has one end adjacent to the mouth 13 of the gas container 10, the other end to which the igniter 40 is provided, and a piston main body 32 and a pointed portion 33 that constitute a piston within the passage 31 are disposed between the one end and the other end. The piston main body 32 is made of a material (e.g., rigid polyurethane foam) that can deform to conform to the shape of the passage 31. At least an end 32a of the piston main body 32 on the igniter 40 side functions as a blocking member that blocks the passage 31 in an initial state and is integral with the piston main body 32. During operation, the end 32a slides along the passage 31 together with the piston main body 32 toward the mouth 13 of the gas container 10. 3(a), the pointed portion 33 includes a seat 33a, a shaft portion 33b formed to protrude from approximately the center of the seat 33a, and a pointed portion 33c provided at the tip of the shaft portion. The seat 33a and the end of the piston body 32 on the mouth 13 side may or may not be fixed to each other.

[0017] Furthermore, at least a portion of the tubular member 30 where the igniter 40 is provided is provided in the tubular member 20 so as to protrude from the side circumferential surface of one end side (first tubular portion 21) of the tubular member 20. Furthermore, the portion of the tubular member 30 other than the portion protruding from the side circumferential surface of the tubular member 20 is disposed inside the tubular member 20 in a state where a space is provided through which the gas can pass from the mouth 13 of the gas container 10 to the gas outlet 25 (for example, a state in which the outer diameter of the tubular member 30 is smaller than the diameter of the passage 23 of the tubular member 20 and a gap through which the gas can pass is provided between the outer circumferential wall of the tubular member 30 and the inner circumferential wall of the tubular member 20).

[0018] Igniter 40 comprises a base frame (not shown) into which a pair of terminal pins 41 are inserted and which holds the pair, and a squib cup 42 (cup-shaped member) attached to the base frame, with a resistor (bridge wire) attached to connect the tips of terminal pins 41 inserted into squib cup 42, and an ignition charge filled in squib cup 42 so as to surround or come into contact with the resistor. Nichrome wire or the like is generally used as the resistor, and ZPP (zirconium-potassium perchlorate), ZWPP (zirconium-tungsten-potassium perchlorate), lead tricinate, or the like is generally used as the ignition charge. The squib cup 42 may be filled with not only the ignition charge but also a transfer charge, and examples of transfer charges that can be placed together with the ignition charge include a composition made of a metal / oxidizer, such as boron / potassium nitrate, a composition made of titanium hydride / potassium perchlorate, or a composition made of boron / 5-aminotetrazole / potassium nitrate / molybdenum trioxide. The squib cup 42 is generally made of metal or resin.

[0019] When the igniter 40 is activated, a predetermined amount of current flows through the resistor via a terminal pin 41 connected to a connector (not shown) that transmits signals from a collision detection means (described later). When a predetermined amount of current flows through the resistor, Joule heat is generated in the resistor, and the ignition charge begins to burn due to this heat. The high-temperature flame generated by the combustion ruptures the end of the squib cup 42, which contains the ignition charge, on the tubular member 30 side (the portion connected to the inside of the tubular member 30). When nichrome wire is used for the resistor, the time from when the current flows through the resistor to when the igniter 40 is activated is 2 milliseconds or less.

[0020] Next, the operation of gas generator 100 described above when activated will be described. For example, when a vehicle equipped with an airbag device (not shown) incorporating gas generator 100 of the present embodiment collides, the collision is detected by collision detection means separately provided in the vehicle, and igniter 40 is activated based on this. When igniter 40 is activated, the pressure inside igniter 40 increases due to combustion of the ignition charge, causing the tip of squib cup 42 of igniter 40 to rupture, and a flame (blast) flows from the tip of squib cup 42 of igniter 40 into passage 31 of tubular member 30.

[0021] The flame (blast) generated when igniter 40 is activated in this manner is guided to end 32a of piston body 32 (piston) through passage 31. Then, as shown in FIG. 2(b), the flame (blast) moves piston body 32 and sharpened tip 33 along passage 31 toward mouth 13 from the initial state of FIG. 2(a). At this time, the tip of pointed portion 33c of sharpened tip 33 collides with sealing portion 14 with such force that sealing portion 14 is broken, opening mouth 13 of gas container 10. Thereafter, gas discharged from mouth 13 of gas container 10 is ejected to the outside (e.g., into an airbag) through passage 23 and gas outlet 25 in tubular member 20.

[0022] According to the present embodiment, the flame (blast) generated by igniter 40 is directly received by piston main body 32, and can be used more efficiently as propulsion force for sharp tip 33, thereby reducing the output loss of igniter 40 more than before. In other words, it is possible to make gas generator 100 with the same performance as conventional igniters 40 with an igniter 40 that has a smaller output than conventional igniters, and therefore it is possible to make gas generator 100 with the same performance as conventional gas generators, while making it smaller and lighter than conventional gas generators.

[0023] Furthermore, the passage 31 of the tubular member 30 is curved in a substantially L-shape, and the internal piston main body 32 is formed from a hard polyurethane foam (for example, one having a Shore hardness of A30 or more (preferably A50 to A70)) that can deform to follow the shape of the passage 31. Therefore, the piston main body 32 can slide smoothly following the shape. As a result, the output loss of the igniter 40 can be further reduced. Note that when the piston main body 32 is formed from a hard polyurethane foam, a disk-shaped member made of a heat-resistant material (for example, metal) may be provided at the end 32a.

[0024] Furthermore, because tubular member 20 is formed in a substantially L-shape, it can be made shorter in the longitudinal direction of gas generator 100 than if tubular member 20 were formed in a linear shape (simple cylindrical shape). Therefore, it is possible to make gas generator 100 more compact and lightweight than if tubular member 20 were formed in a linear shape (simple cylindrical shape).

[0025] <Modification> A gas generator according to a modified example of the present invention will be described below with reference to Figs. 4 and 5. Fig. 4 is a diagram for explaining the operation of a gas generator according to a modified example of gas generator 100 of the above embodiment, with (a) being a partial cross-sectional schematic diagram showing the initial state and (b) being during operation. The gas generator in Fig. 4 shows only the main parts according to the modified example, and parts not shown are similar to those in the above embodiment, so description and illustration may be omitted. Furthermore, unless otherwise specified, parts having similar functions to those in the above embodiment may be designated by reference numerals with the same last two digits, and description thereof may be omitted.

[0026] The gas generator of this embodiment differs from the first embodiment mainly in that (1) piston main body 132 is a spring, and (2) a disk-shaped blocking member 132a (made of, for example, metal or hard polyurethane foam) is provided at the end of piston main body 132.

[0027] As shown in FIGS. 4 and 5, the piston main body 132 is a coil spring formed by winding in a spiral shape. This coil spring has a spring constant large enough to prevent the coil spring from losing its shape when placed inside the passage 131 of the tubular member 130 (at least enough to maintain the shape shown in FIG. 4(a)). A blocking member 132a is provided at the end of the piston main body 132 on the igniter 140 side so as to block the passage 131 of the tubular member 130 in an initial state. This blocking member 132a is slidable toward the piston main body 132 by the blast of the igniter 140 upon activation. The seat 133a and the end of the piston main body 132 on the mouth 113 side may or may not be fixed to each other. The end of the piston main body 132 on the igniter 140 side and the blocking member 132a may or may not be fixed to each other. Although a coil spring is used in this modified example, other spring members, elastic bodies, etc. may be used as long as they can provide the same function as a coil spring.

[0028] Next, an operation during activation of the gas generator according to this modified example described above will be described. For example, when a vehicle equipped with an airbag device (not shown) incorporating the gas generator according to this modified example collides, the collision is detected by collision detection means separately provided in the vehicle, and igniter 140 is activated based on this detection. When igniter 140 is activated, the pressure inside igniter 140 increases due to combustion of the ignition charge, causing the tip of squib cup 142 of igniter 140 to rupture, and a flame (blast) flows from the tip of squib cup 142 of igniter 140 into passage 131 of tubular member 130.

[0029] The flame (blast) generated when igniter 140 is activated in this manner is guided to closing member 132a through passage 131. Then, as shown in FIG. 4(b), from the initial state of FIG. 4(a), the flame (blast) causes closing member 132a to slide along passage 131 toward opening 113, pushing piston body 132 and sharp tip 133, thereby moving piston body 132 and sharp tip 133 along passage 131 toward opening 113. At this time, the tip of pointed portion 133c of sharp tip 133 collides with sealing portion 114 with such force that sealing portion 114 is broken, opening opening 113 of gas container 110. Thereafter, as in the above embodiment, gas discharged from opening 113 of gas container 110 is ejected to the outside (e.g., into an airbag) through a passage (not shown) and a gas outlet (not shown) in the tubular member (not shown).

[0030] According to this modification, the same effects as those of the above embodiment can be achieved.

[0031] Although the embodiments of the present invention have been described above with reference to the drawings, it should be understood that the specific configurations are not limited to these embodiments. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0032] 10, 110 Gas container 11, 111 bottles 12 Male thread 13, 113 mouths 14, 114 Sealing part 20 Cylindrical member 21 First tubular part 22 Second tubular part Aisles 23, 31, 131 24 Female thread 25 Gas outlet 30, 130 Tubular members 32, 132 Piston body 32a end 33, 133 Sharp part 33a, 133a seat 33b, 133b shaft part 33c, 133c point 40, 140 igniter 41, 141 terminal pins 42, 142 Squib Cup 100 Gas Generator 132a Closure member

Claims

1. a gas container having a mouth and filled with high-pressure gas; a sealing portion that seals the mouth of the gas container; an igniter that generates a blast that serves as a driving force for opening the sealing portion; a piston that moves toward the opening of the gas container by the blast of the igniter and breaks the sealing portion to open it; a substantially L-shaped tubular member having a passage formed therein so as to be curved in a substantially L shape, one end of which is adjacent to the opening of the gas container and the igniter is provided at the other end, and the piston is disposed in the passage between the one end and the other end so as to slide along an inner wall from the other end to the one end, and the blast wave of the igniter is guided to the piston; Equipped with The piston is A piston main body; a sharpened portion provided at an end of the piston body on the sealing portion side and adjacent to the opening of the gas container, the sharpened portion being capable of breaking the opening of the gas container; a blocking member provided at an end of the piston body on the igniter side and adjacent to the igniter, the blocking member blocking the passage in an initial state; A gas generator comprising:

2. A gas container having a mouth into which high-pressure gas is filled; a sealing portion that seals the mouth of the gas container; an igniter that generates a blast that serves as a driving force for opening the sealing portion; a piston that moves toward the opening of the gas container by the blast of the igniter and breaks the sealing portion to open it; a substantially L-shaped tubular member having an approximately L-shaped passage therein, one end of which is adjacent to the opening of the gas container, the other end of which is provided with the igniter, the piston being disposed in the passage between the one end and the other end, and which guides the blast of the igniter to the piston; Equipped with The piston is A piston main body; a sharpened portion provided at an end of the piston body on the sealing portion side and adjacent to the opening of the gas container, the sharpened portion being capable of breaking the opening of the gas container; a blocking member provided at an end of the piston body on the igniter side and adjacent to the igniter, the blocking member blocking the passage in an initial state; It has the piston body and the closing member are made of hard urethane foam, 10. A gas generator according to claim 9, wherein the closing member is integrated with the piston body.

3. A gas container having a mouth into which high-pressure gas is filled; a sealing portion that seals the mouth of the gas container; an igniter that generates a blast that serves as a driving force for opening the sealing portion; a piston that moves toward the opening of the gas container by the blast of the igniter and breaks the sealing portion to open it; a substantially L-shaped tubular member having an approximately L-shaped passage therein, one end of which is adjacent to the opening of the gas container, the other end of which is provided with the igniter, the piston being disposed in the passage between the one end and the other end, and which guides the blast of the igniter to the piston; Equipped with The piston is A piston main body; a sharpened portion provided at an end of the piston body on the sealing portion side and adjacent to the opening of the gas container, the sharpened portion being capable of breaking the opening of the gas container; a blocking member provided at an end of the piston body on the igniter side and adjacent to the igniter, the blocking member blocking the passage in an initial state; It has The piston body is made of a spring, 10. A gas generator according to claim 9, wherein the blocking member is a disk-shaped member fixed to an end of the spring on the igniter side.

4. a substantially L-shaped cylindrical member having one end connected to the tip of the opening of the gas container and the other end having a gas outlet for ejecting gas when the opening of the gas container is broken; 4. The gas generator according to claim 1, wherein at least a portion of the tubular member where the igniter is provided is provided in the tubular member so as to protrude from a side circumferential surface on one end side of the tubular member, and a portion of the tubular member other than the portion protruding from the side circumferential surface on one end side of the tubular member is disposed inside the tubular member in a state where a space is formed that allows gas to pass from a mouth of the gas container to the gas outlet.

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