Gas generator and airbag device

Abstract

To decrease a temperature of a gas jetted from a gas generator of an airbag device.SOLUTION: A gas generator generates a gas for expanding and deploying an airbag and includes: a main part which has a cylindrical shape and discharges the gas generated therein from discharge ports provided at a peripheral wall part of the cylindrical shape; and pipe parts each of which has a pipe-like shape, is fixed to the main part at a predetermined position while causing the interior of the pipe-like shape to communicate with the interior of the main part through the discharge port, and receives the gas discharged from the discharge port into an inner part of the pipe-like shape to jet the gas from a jet port provided at a position away from the discharge port.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a gas generator that generates gas for inflating and deploying an airbag, and an airbag device that includes the gas generator. [Background technology]

[0002] Conventionally, airbag devices have been used to protect vehicle occupants in the event of a collision of a vehicle such as an automobile. The airbag device detects a vehicle collision and inflates and deploys an airbag. The deployed airbag catches the occupant who is moving due to the impact of the collision, thereby protecting the occupant.

[0003] For example, Patent Document 1 discloses a gas generator that burns a gas generating agent to generate gas and inflate an airbag. A cylindrical gas generator has a housing peripheral wall provided with multiple gas outlets arranged circumferentially. When a vehicle collision is detected, an igniter provided inside the housing is activated to ignite an ignition charge. The combustion of the ignition charge ignites a transfer charge, generating thermal particles. When the thermal particles ignite the gas generating agent filled inside the housing, the gas generating agent burns and generates a large amount of gas. The generated gas is ejected from the gas outlet to the outside of the housing via a filter provided inside the peripheral wall of the housing. The filter, made of a metallic material, is provided to remove residue (slag) from the ejected gas. The filter is also expected to have the effect of cooling the gas.

[0004] Patent Document 2 also discloses a gas generator that ejects gas from an outlet provided in a peripheral wall. This gas generator ejects gas into a chamber provided as a space for gas diffusion. A conduit for passing the gas is connected to the chamber. The gas in the chamber passes through the conduit and is ejected from multiple nozzles formed in the conduit, inflating and deploying the airbag. A suction port that is opened and closed by a valve is provided in the housing to which the airbag is fixed. When the gas generator is activated, the valve opens and air is drawn into the airbag through the suction port. The valve is closed while the airbag is inflating so that the air drawn into the airbag and inflation gas do not escape through the suction port. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-185907 [Patent Document 2] U.S. Patent No. 10,124,759 Summary of the Invention [Problem to be solved by the invention]

[0006] The gas generator described above is known as a pyrotechnic gas generator (inflator) that burns a gas generating agent called pyrolysis and inflates an airbag with the generated gas. Pyrotechnic gas generators that eject gas generated by combustion require improved cooling functionality to lower the gas temperature after ejection.

[0007] For example, as described in Patent Document 2, by ejecting gas from a small-diameter nozzle and increasing the gas ejection speed, a cooling effect that lowers the gas temperature after ejection can be expected. However, with a structure in which the gas generated by a gas generator is temporarily stored in a chamber and then sent to a conduit for ejection, the energy of the gas cannot be fully utilized.

[0008] The present disclosure has been made in consideration of the above-mentioned prior art, and one of its objectives is to provide a gas generator that can eject gas at high speed, and an airbag device that draws air into an airbag by using the fluid energy of the gas. [Means for solving the problem]

[0009] A gas generator according to the present disclosure is a gas generator that generates gas to inflate and deploy an airbag, and includes: a main body portion having a cylindrical shape and discharging the gas generated therein from an outlet provided in a peripheral wall portion of the cylindrical shape; and a pipe portion having a tubular shape and fixed at a predetermined position relative to the main body portion such that the interior of the tubular shape communicates with the interior of the main body portion via the outlet, and the pipe portion receives the gas discharged from the outlet into the interior of the tubular shape and ejects the gas from an outlet provided at a position spaced apart from the outlet. In the above configuration, the main body portion may have the outlet at each of a plurality of spaced positions on the peripheral wall portion, and the pipe portion may be provided at each of the plurality of positions. The main body portion may discharge the gas from the outlet in a first direction, and the pipe portion may eject the gas from the outlet in a second direction different from the first direction. The pipe portion may have the outlet at each of a plurality of spaced positions on the tubular wall portion. The pipe portion may communicate with the inside of the main body portion via the outlet at one axial end side of the pipe shape, and the other end side may be closed.

[0010] In the above configuration, the area of ​​the ejection port formed in the pipe portion may be smaller than the area of ​​the discharge port formed in the main body portion. The total area of ​​the plurality of ejection ports provided in the pipe portion may be equal to or smaller than the area of ​​the discharge port.

[0011] In the above configuration, the pipe portion may be fixed to the exhaust port in a positional relationship in which the direction of gas discharge from the exhaust port is the axial direction of the tubular shape, and the pipe portion may be fixed to the exhaust port in a positional relationship in which the opening periphery of the tubular end portion is outside the periphery of the exhaust port.

[0012] The airbag device according to the present disclosure is an airbag device that inflates and deploys a folded airbag, and includes an airbag, a gas generator having the above-described configuration that generates gas that inflates and deploys the airbag, and an airbag case that houses the gas generator and the folded airbag.

[0013] The above configuration may further include a retainer that holds the main body and the pipe of the gas generator in a predetermined positional relationship.

[0014] In the above configuration, the airbag may be formed with an opening that allows the tube portion of the gas generator and the retainer to be inserted into the airbag after the tube portion is fixed to the retainer, and the opening may have a shape that includes a slit portion that expands a part of a shape formed to match the main body portion of the gas generator so that the retainer with the tube portion fixed thereto can be inserted.

[0015] In the above configuration, the pipe portion of the gas generator may be fixed at a predetermined position, and the retainer may be inserted into the airbag together with the pipe portion through an opening of the airbag and housed in the airbag case together with the airbag, and the gas generator may have a part of its main body inserted into the airbag from outside the airbag case through an opening formed in the airbag case, and the gas generator may be fixed at a predetermined position in the airbag case within the airbag, with the inside of the pipe portion fixed to the retainer communicating with the inside of the main body through the outlet provided in the main body. [Effects of the Invention]

[0016] According to the gas generator according to the present disclosure, gas generated in the main body portion can be discharged into the tubular portion and ejected through the tubular portion from an ejection port located away from the main body portion. This makes it possible to increase the speed of the ejected gas compared to conventional devices, increases the amount of air intake, and lowers the gas temperature inside the airbag. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a schematic diagram for explaining an overview of a gas generator and an airbag device according to this embodiment. [Figure 2] FIG. 2 is a perspective view for explaining a main body and a pipe of the gas generator. [Figure 3] FIG. 3 is a diagram for explaining the internal structure of the gas generator. [Figure 4] FIG. 4 is a perspective view for explaining the configuration of the airbag device. [Figure 5] FIG. 5 is a diagram illustrating the configuration of the retainer. [Figure 6] FIG. 6 is a diagram for explaining a method of assembling the airbag device. [Figure 7] FIG. 7 is a top view for explaining a configuration example of a gas generator and an airbag device. [Figure 8] FIG. 8 is a diagram showing a different configuration example of the pipe section. [Figure 9] FIG. 9 is a diagram showing different examples of outlets formed in the peripheral wall of the main body. [Figure 10] FIG. 10 is a diagram showing different examples of the cross-sectional shape of the pipe portion. [Figure 11] FIG. 11 is a diagram showing examples of different shapes of the pipe portion and different positional relationships with the main body portion. [Figure 12] FIG. 12 is a diagram showing still another example of the shape of the pipe portion and its positional relationship with the main body portion. DETAILED DESCRIPTION OF THE INVENTION

[0018] A gas generator and an airbag device according to the present disclosure will be described below with reference to the accompanying drawings. The gas generator according to the present disclosure is a pyrotechnic gas generator that generates gas by burning a gas generating agent therein. Pyrotechnic gas generators are used, for example, in vehicles such as automobiles to inflate and deploy airbags that protect occupants in the event of a collision. Pyrotechnic gas generators and airbag devices that inflate and deploy airbags using gas generators are conventionally known. Therefore, in this embodiment, a description of the basic structure and operation of conventionally known gas generators and airbag devices will be omitted. An example of the basic structure and operation of a gas generator that generates gas using a gas generating agent therein is described in Japanese Patent Application Laid-Open No. 2017-185907 by the applicant of the present application.

[0019] [Airbag device overview] Fig. 1 is a schematic diagram for explaining an overview of a gas generator 10 and an airbag device 1 according to this embodiment. The airbag device 1 includes an airbag 200, a gas generator 10 that inflates and deploys the airbag 200, and an airbag case 40 that houses the airbag 200 and the gas generator 10. In Fig. 1, only a part of the airbag 200 that inflates and deploys when gas is ejected from the gas generator 10 is shown by a broken line.

[0020] The airbag device 1 may be provided with a retainer 50 that holds the gas generator 10 and the airbag 200. An embodiment in which the retainer 50 holds only one of the gas generator 10 and the airbag 200 may also be adopted. An embodiment in which the airbag device 1 does not have the retainer 50, and the airbag case 40 also functions as the retainer 50.

[0021] The gas generator 10 and the airbag 200 before deployment are housed inside a box-shaped airbag case 40 with an open top. The shape of the airbag case 40 is not particularly limited and will vary depending on the specifications, usage mode, etc. of the airbag device 1, but for ease of explanation, the following description will be given taking as an example a case where the airbag case 40 is a rectangular parallelepiped box.

[0022] In some of the drawings described in this embodiment, coordinate axes are shown so that the relationship between each component can be understood. In the following description, the longitudinal direction of the bottom surface of the rectangular airbag case 40 is defined as the X-axis direction, the lateral direction as the Y-axis direction, and the up-down direction as the Z-axis direction, as shown in Fig. 1 .

[0023] The gas generator 10 is fixed to an airbag case 40 that is open upward (positive direction of the Z axis). An airbag 200 is fixed to the airbag case 40 so as to be deployable. The airbag 200 is normally in a folded state. For example, the gas generator 10 and the airbag 200 are fixed to predetermined positions in the airbag case 40 using a retainer 50, which will be described in detail later.

[0024] As shown in FIG. 1, gas generator 10 has a main body portion 20 and a pipe portion 30 extending outward from main body portion 20. Main body portion 20 has a cylindrical shape and is closed at its upper and lower surfaces. An outlet port 20a, which is a through-hole that connects the inside and outside of main body portion 20, is formed in the peripheral wall portion of main body portion 20 (see FIG. 2). In other words, main body portion 20 has a cylindrical shape made up of an upper surface, a lower surface, and a peripheral wall portion that connects the upper and lower surfaces, and outlet port 20a is formed in the peripheral wall portion, i.e., in the side surface portion. For example, a plurality of outlet ports 20a are provided on the peripheral wall portion of main body portion 20 at different positions in the circumferential direction.

[0025] Pipe portions 30 having a pipe shape are provided corresponding to each exhaust port 20a of main body portion 20. Each pipe portion 30 is fixed at a predetermined position relative to main body portion 20, with the inside of the pipe shape communicating with the inside of main body portion 20 via exhaust port 20a. One axial end of pipe portion 30 communicates with the inside of main body portion 20, while the other end is closed. A gas outlet 30a, which is a through hole that communicates the inside and outside of pipe portion 30, is formed in the pipe wall of pipe portion 30. For example, a plurality of outlets 30a are provided at different positions in the axial direction of pipe portion 30. When gas generator 10 ejects gas, the inside of main body portion 20 communicates with the outside of gas generator 10 via outlet 20a on the side of main body portion 20, the inside of pipe portion 30, and outlet 30a of pipe portion 30.

[0026] One pipe section 30 is provided corresponding to each of the multiple exhaust ports 20a of the main body section 20. For example, the pipe section 30 is fixed to the exhaust port 20a of the main body section 20 in a positional relationship such that the direction of gas discharged from the exhaust port 20a is the axial direction of the pipe section 30. The pipe section 30 is fixed in a positional relationship such that the opening periphery of the axial end is outside the opening periphery of the exhaust port 20a.

[0027] When it becomes necessary to deploy the airbag 200, a gas generating agent burns inside the main body 20, generating gas, as in a conventional pyrotechnic gas generator. The gas generated inside the main body 20 is discharged into the inside of the tubular portion 30 from an outlet 20a provided in the main body 20, as shown by the dashed arrow in Fig. 1. The gas that flows from the main body 20 into the inside of the tubular portion 30 is ejected from the outlet 30a of the tubular portion 30, as shown by the solid arrow in Fig. 1.

[0028] Main body portion 20 discharges gas from the peripheral wall portion outward in the axial direction of pipe portion 30, but pipe portion 30 ejects the gas received from main body portion 20 upward. That is, gas generator 10 uses pipe portion 30 to eject gas in a direction different from the direction in which gas is ejected by main body portion 20. The gas is ejected to the outside from an ejection port 30a of pipe portion 30 provided at a position away from exhaust port 20a of main body portion 20, specifically at a position away from main body portion 20.

[0029] The gas ejected from the ejection port 30a of the pipe portion 30 flows into the inside of the folded airbag 200. As a result, the airbag 200 inflates upward and deploys, as shown partially by the dashed line in FIG.

[0030] The airbag case 40 is formed with openings 40a for drawing air from the outside to the inside of the airbag case 40. The openings 40a are provided corresponding to the outlets 30a of each pipe section 30. In the example shown in Fig. 1, openings 40a are formed in four places on the bottom surface of the airbag case 40, corresponding to the outlets 30a of each of the four pipe sections 30 (see Fig. 7).

[0031] When high-speed gas is ejected from the outlet 30a of the tubular portion 30, a negative pressure state is created around the outlet 30a and inside the inflating airbag 200, and air flows in through the opening 40a. In addition to the gas ejected from the outlet 30a, air flows in through the opening 40a, and the airbag 200 is inflated and deployed at high speed due to the so-called aspiration effect. The gas generator 10 is also capable of inflating and deploying an airbag 200 that is larger than conventional ones, using the ejected gas and the air that is drawn in through the opening 40a as a result.

[0032] In gas generator 10, gas generated inside main body portion 20 is not ejected directly to the outside from exhaust port 20a of main body portion 20, but is discharged into tube portion 30 and ejected from ejection ports 30a provided in the tube wall. The area of ​​each ejection port 30a is smaller than the area of ​​exhaust port 20a. Therefore, compared to when gas is ejected directly to the outside from exhaust port 20a, the speed of gas ejected from each ejection port 30a is higher, and the gas temperature after ejection can be lowered. Furthermore, the increased gas ejection speed makes it possible to obtain a higher aspiration effect than conventionally. Note that, in order to eject gas at high speed, it is preferable that the total area of ​​the multiple ejection ports 30a provided in tube portion 30 corresponding to one exhaust port 20a is smaller than the area of ​​this one exhaust port 20a.

[0033] In a structure such as that seen in conventional devices in which gas discharged from a main body portion is first discharged into a large separate space such as a chamber formed to cover the main body portion, and then discharged from this space into a conduit extending further outward, and then jetted out from the conduit, there is a possibility that some of the energy of the gas is lost along the way. On the other hand, gas generator 10 discharges gas generated inside main body portion 20 directly from outlet 20a into the inside of tubular portion 30, and jets out from jet outlet 30a of tubular portion 30. Therefore, the speed of the gas jetting out from jet outlet 30a can be made higher than when gas is jetted indirectly into tubular portion 30 via a separate space.

[0034] Furthermore, in the structure seen in conventional devices in which gas is ejected directly outward from the side of the main body portion to inflate the airbag 200 upward, it is necessary to provide a separate member inside the airbag case 40 to distribute the gas or change the direction of the gas flow. On the other hand, the gas generator 10 can eject gas generated inside the main body portion 20 from an ejection port 30a located away from the main body portion 20 by utilizing the tubular portion 30. By providing multiple ejection ports 30a in the tubular wall portion of the tubular portion 30, gas can be ejected from desired positions over a wide range inside the airbag case 40.

[0035] [Gas generator configuration example] 2 is a perspective view for explaining main body section 20 and pipe section 30 of gas generator 10. Fig. 2 shows only two of the four pipe sections 30 shown in Fig. 1.

[0036] As shown in FIG. 2, one axial end of each pipe section 30 is a closed end 30b. A plurality of ejection ports 30a are formed in the pipe wall of each pipe section 30 at positions spaced apart in the axial direction. The main body section 20 has a cylindrical shape. More specifically, the main body section 20 has a generally cylindrical shape with closed upper and lower surfaces, and the upper surface and the upper end of the peripheral wall, and the lower surface and the lower end of the peripheral wall, connected by curved surfaces. A plurality of ejection ports 20a are formed in the side surface of the main body section 20 at positions spaced apart in the circumferential direction. The upper and lower surfaces of the main body section 20 may be flat or curved.

[0037] Each pipe section 30 is provided at a position where the open end does not block the outlet 20a so that the interior of the main body section 20 and the interior of the pipe section 30 communicate via the entire outlet 20a. That is, the open end of the pipe section 30 is fixed to align with the outlet 20a so that the position of the outlet 20a is located inside the opening of the axial end of the pipe section 30.

[0038] When the main body 20 and the pipe 30 are fixed in the airbag case 40 in a predetermined positional relationship, it is preferable that there is no gap between the open end of the pipe 30 and the outer peripheral surface of the main body 20 so that gas does not leak from the gap. However, there may be a gap between the open end of the pipe 30 and the outer peripheral surface of the main body 20 as long as it does not adversely affect the flow of gas from the inside of the main body 20 to the inside of the pipe 30.

[0039] For example, when the open end surface of the pipe portion 30 perpendicular to the axial direction is brought into contact with the peripheral wall of the main body portion 20 having a circular cross section, a gap may be formed between the main body portion 20 and the pipe portion 30. This gap may be filled using conventional techniques, such as by welding or by connecting the pipe portion 30 and the main body portion 20 with a screw structure, or it may be left as is. Also, for example, when the entire open end portion of the pipe portion 30 is positioned slightly away from the main body portion 20, the gap may be filled or left as is.

[0040] A flange portion 20b used to fix main body portion 20 is provided in the middle portion of main body portion 20 in the vertical direction. Fixing holes 20c, which are through holes for fixing main body portion 20, i.e., gas generator 10, are formed in multiple locations on flange portion 20b.

[0041] Fig. 3 is a diagram for explaining the internal structure of gas generator 10. Fig. 3(a) is a schematic perspective cross-sectional view showing a partial cross section of gas generator 10 fixed to airbag case 40 by means of retainer 50. Fig. 3(b) is a schematic cross-sectional view for explaining the relationship between gas generator 10 and airbag case 40. Note that Fig. 3 omits illustration of conventionally known components such as a filter and gas generating agent inside gas generator 10, and shows only the components necessary for explaining gas generator 10 according to the present embodiment.

[0042] As shown in FIG. 3(a), gas generated inside the main body portion 20 having a substantially cylindrical shape is discharged from an outlet 20a formed in the peripheral wall portion and flows into the inside of the tubular portion 30. As shown in FIG. 3(b), the gas that has flowed into the tubular portion 30 moves inside the tubular portion 30, one end of which is closed by a closed end 30b, and is ejected to the outside of the gas generator 10 from a plurality of ejection ports 30a formed in the tubular wall portion. The ejection ports 30a are provided so as to eject gas in a direction that inflates the airbag 200. The gas ejected from the ejection ports 30a flows into the airbag 200, causing the airbag 200 to inflate and deploy.

[0043] An opening 40a is formed in the bottom surface of the airbag case 40 to coincide with the discharge ports 30a of the tubular portion 30. For example, the opening edge of the opening 40a in the axial direction of the tubular portion 30 is located further outward than the discharge ports 30a located on both outer sides in the axial direction. The opening 40a is formed in a positional relationship such that, when viewed from above, the discharge ports 30a located on both outer sides in the axial direction of the tubular portion 30 are visible inside the opening. Furthermore, within the bottom surface of the flat-shaped airbag case 40, the width of the opening 40a in a direction perpendicular to the axial direction of the tubular portion 30 is wider than the width of the tubular portion 30 (the outer diameter of the circular tube). When gas is discharged from the discharge ports 30a, air is drawn from the outside of the airbag case 40 into the airbag case 40 through the opening 40a.

[0044] The position, shape, and dimensions of the opening 40a are examples and are not intended to be limiting. For example, a plurality of openings 40a may be provided in the bottom surface of the airbag case 40 corresponding to one pipe portion 30, or an opening may be provided in the side surface of the airbag case 40 instead of or in addition to the opening 40a in the bottom surface.

[0045] The material of the airbag case 40 is not particularly limited, but for example, a metal airbag case 40 may be used. The materials of the main body 20 and tube 30 that constitute the gas generator 10 are also not particularly limited, but, for example, the main body 20 may be made of metal as in conventional pyrotechnic gas generators, and the tube 30 may also be made of the same metal as the main body 20. For example, one axial end of a metal circular tube may be closed and fixed with a lid prepared to fit the inner diameter of the circular tube, and used as the tube 30. The method of fixing the lid to the tube 30 is not particularly limited, and conventionally known methods such as welding, crimping, and screws may be used.

[0046] The method for fixing each tube section 30 in a predetermined position relative to the main body section 20 of the gas generator 10 is not particularly limited, and may be performed by a conventionally known method such as welding, crimping, riveting, or screwing, as with the cover body of the tube section 30.

[0047] In the airbag device 1 according to this embodiment, the airbag 200 and the gas generator 10 are assembled to the airbag case 40 using the retainer 50, which makes it possible to easily assemble the airbag device 1. The configuration of the airbag device 1 that uses the retainer 50 will be described below.

[0048] [Airbag device configuration example] Fig. 4 is a perspective view for explaining the configuration of the airbag device 1. In Fig. 4, only a part of the airbag 200 is shown by a broken line, and as for the airbag case 40, only the fixing hole 40b and the through-hole 40c on the bottom surface used to fix the gas generator 10 are shown.

[0049] As shown in FIG. 4, the airbag 200 and the gas generator 10 including the main body portion 20 and the pipe portion 30 are fixed to the airbag case 40 in a predetermined positional relationship using a retainer 50.

[0050] The bottom surface of the airbag case 40 is formed with a fixing hole 40b for fixing the gas generator 10 and the airbag 200 using a retainer 50, and a through-hole 40c that matches the shape of the main body part 20 of the gas generator 10. For example, the through-hole 40c has a circular shape that is slightly larger than the outer diameter of the main body part 20, which has a substantially cylindrical shape, so that the main body part 20 can be inserted.

[0051] Fig. 4 shows a retainer 50 to which the pipe portion 30 is fixed. Fig. 5 is a diagram for explaining the configuration of the retainer 50. As shown in Fig. 5(a), the retainer 50 includes a base member 51 having a rectangular plate shape and a plurality of bolts (fastening members) 52. In the example shown in Fig. 5, four bolts 52 are used to fix the base member 51 having a rectangular shape to each of the four corners.

[0052] Base member 51 is formed with through hole 51a that matches the shape of main body portion 20 of gas generator 10. For example, through hole 51a has a circular shape that is slightly larger than the outer diameter of main body portion 20, which has a substantially cylindrical shape, so that main body portion 20 can be inserted. Also, base member 51 is formed with groove portion 51c for positioning tube portion 30 of gas generator 10.

[0053] Through hole 51a and groove portion 51c of base member 51 are formed in accordance with the positional relationship between main body portion 20 and pipe portion 30 of gas generator 10. Specifically, through hole 51a and groove portion 51c are formed in base member 51 so that when main body portion 20 and pipe portion 30 are fixed to airbag case 40 using retainer 50 as shown in Fig. 4, they have a predetermined positional relationship in which the interior of main body portion 20 and the interior of pipe portion 30 communicate with each other.

[0054] The material of the base member 51 is not particularly limited, but for example, a thin metal plate may be pressed to form grooves 51c that match the outer shape of the pipe portion 30, and the grooves 51c may have a curved side shape as shown in Fig. 5(b). The grooves 51c may also be formed by cutting a metal plate.

[0055] A bolt 52 is fixed to the base member 51. The fixing method is not particularly limited, and for example, the metal bolt 52 may be passed through a through hole 51b formed in the base member 51 and then welded and fixed to the base member 51. Alternatively, a screw hole may be formed in the through hole 51b of the base member 51, and the bolt 52 may be fastened by tightening the screw hole.

[0056] Pipe portion 30 of gas generator 10 is fixed to base member 51 so as to be aligned with groove portion 51c, as shown by the solid arrow in Figure 5(a). For example, metal pipe portion 30 may be fixed to base member 51 by welding. Note that, as long as pipe portion 30 can be positioned and fixed to a predetermined position in base member 51, pipe portion 30 may be fixed to base member 51 without providing groove portion 51c in base member 51.

[0057] 4, the airbag 200 and the main body 20 are assembled to the airbag case 40 using the retainer 50 to which the pipe portion 30 and the bolts 52 are fixed. The airbag 200, the airbag case 40, and the gas generator 10 are fixed using the bolts 52 and nuts 62 fixed to the retainer 50.

[0058] 6A and 6B are diagrams illustrating a method of assembling the airbag device 1. Fig. 6A shows a view of the retainer 50 to which the pipe portion 30 is fixed, viewed from below (from the negative Z-axis direction). As shown in Fig. 6A, the airbag 200 is formed with insertion openings 300 (300a, 300b) that are openings for inserting the retainer 50, to which the pipe portion 30 and the bolts 52 have already been fixed, into the airbag 200, and fixing holes 301 that are openings for fixing the airbag 200 to the airbag case 40.

[0059] Insertion port 300 includes a circular portion 300a formed to fit main body portion 20 of gas generator 10, and two slit portions 300b expanded outward on both sides from circular portion 300a. For example, circular portion 300a has a circular shape that is slightly larger than the outer diameter of main body portion 20, which has a substantially cylindrical shape, so that main body portion 20 can be inserted.

[0060] The slit portion 300b is formed to have a size that allows the retainer 50, to which the pipe portion 30 is fixed, to be inserted into the inside of the airbag 200. Specifically, as shown in Fig. 6(a), the width A2 of the slit portion 300b in the slit direction (X-axis direction) is larger than the diameter A1 of the circular portion 300a, and the insertion opening 300 can be widened in the direction perpendicular to the slit direction (Y-axis direction), so that the retainer 50, to which the pipe portion 30 and the bolt 52 have been previously fixed, can be inserted into the inside of the airbag 200 from the insertion opening 300 as shown by the arrow.

[0061] As shown in FIG. 6(b), the bolts 52 of the retainer 50 inserted inside the airbag 200 are inserted into the corresponding fixing holes 301 of the airbag 200. The tips of the bolts 52 exposed to the outside of the airbag 200 are inserted from above the airbag case 40 into the corresponding fixing holes 40b in the bottom surface, so that the tips of the bolts 52 are exposed outside the bottom surface of the airbag case 40. The portion of the gas generator 10 above the flange portion 20b is inserted from below the airbag case 40 into the through-hole 40c in the bottom surface. The main body portion 20 of the gas generator 10 is inserted into the inside of the airbag 200 through the insertion port 300 of the airbag 200. At this time, the bolts 52 exposed downward and outside from the bottom surface of the airbag case 40 are inserted into the fixing holes 20c in the flange portion 20b of the gas generator 10. The tip of the bolt 52 exposed from the fixing hole 20c to the outside of the lower surface of the flange portion 20b is received from below by a nut 62 and tightened. In this way, the airbag 200 and the gas generator 10 including the main body portion 20 and the tube portion 30 are fixed in a predetermined position relative to the airbag case 40 using the retainer 50.

[0062] Main body portion 20 of gas generator 10 is fixed to airbag case 40 by retainer 50, with a portion of the main body portion above flange portion 20b, where discharge port 20a is formed, inserted into airbag 200. Main body portion 20 is positioned and fixed by retainer 50 inside airbag 200 so that discharge port 20a and pipe portion 30 fixed to retainer 50 have a predetermined positional relationship.

[0063] Bolt 52 and nut 62 are one example of members for fixing retainer 50, specifically pipe portion 30 fixed to retainer 50, and main body portion 20 of gas generator 10 in a predetermined positional relationship, and the fixing method is not particularly limited. For example, a mode may be adopted in which a threaded hole is formed in retainer 50 instead of bolt 52, and bolts are used instead of nuts 62 for fixing. Other conventionally known fixing methods, such as caulking or rivets, may also be used.

[0064] The method of fixing the gas generator 10 and the airbag 200 to the airbag case 40 is also an example, and the fixing method is not particularly limited. For example, at least one of the gas generator 10 and the airbag 200 may be fixed to the airbag case 40 by using another member instead of or in addition to the retainer 50.

[0065] Fig. 7 is a top view for explaining a configuration example of the gas generator 10 and the airbag device 1. For example, the gas generator 10 has a substantially cylindrical shape with an outer diameter d1 of the cylindrical part of the main body 20 shown in Fig. 7 being 60 to 70 mm and a height dimension of 30 to 40 mm. For example, the airbag case 40 has a rectangular parallelepiped box shape with a dimension in the X-axis direction of approximately 200 mm, a dimension in the Y-axis direction of approximately 100 mm, and a dimension in the Z-axis direction of approximately 30 mm.

[0066] 7, gas generator 10 is positioned and fixed to the center of the bottom surface of airbag case 40. For example, gas generator 10 is fixed to airbag case 40 in a positional relationship such that a straight line in the Z axis direction passing through the intersection of a center line CL1 in the longitudinal direction (X axis direction) of the bottom surface of airbag case 40, which has a rectangular shape, and a center line CL2 in the lateral direction (Y axis direction), coincides with the cylindrical axis of gas generator 10, which has a substantially cylindrical shape.

[0067] The four pipe sections 30 of gas generator 10 are fixed in a regular arrangement to main body section 20 at positions extending radially from the cylindrical axis of main body section 20, which has a substantially cylindrical shape. For example, pipe section 30 and main body section 20 are fixed in a positional relationship such that the center of outlet 20a, which has a circular shape with a diameter of 6 mm and is provided in main body section 20, is aligned with the center of the circular cross section of pipe section 30, which has a circular pipe shape with an inner diameter of 8 mm, and the axial direction of pipe section 30 is perpendicular to the cylindrical axis of main body section 20.

[0068] Each pipe portion 30 is fixed so that its closed end 30b is located near a corner of the rectangular airbag case 40. For example, a pipe portion 30 having a circular pipe shape with an outer diameter of 10 to 12 mm and an axial length of 60 to 65 mm is fixed to the main body portion 20 with an angle α shown in Fig. 7 being approximately 20 to 25 degrees. In the example shown in Fig. 7, the center of the bottom of the airbag case 40 is on the cylindrical axis of the main body portion 20 of the gas generator 10, and the four pipe portions 30 are fixed to the main body portion 20 in a positional relationship that is line-symmetrical with respect to a center line CL1 in the longitudinal direction of the bottom and line-symmetrical with respect to a center line CL2 in the lateral direction.

[0069] A plurality of ejection ports 30a are formed in a regular arrangement in the tube wall of each tube section 30. For example, five ejection ports 30a with a diameter of 2 to 2.5 mm are formed in each tube section 30 at equal intervals in the axial direction. For example, as shown in Fig. 7, when viewed from above, each ejection port 30a is formed in each tube section 30 in a positional relationship such that a straight line obtained by connecting the centers of each circular ejection port 30a coincides with the axis of the tube section 30.

[0070] However, the shapes, dimensions, and positional relationships of the components described in Fig. 7 are merely examples and do not limit the shapes, dimensions, and positional relationships of the gas generator 10 and the airbag device 1. The shapes, dimensions, and positional relationships of the components constituting the airbag device 1 are set according to the vehicle in which the airbag device 1 is used. For example, if the airbag 200 used in the vehicle is large, the airbag device 1 also becomes large. Furthermore, for example, when the airbag device 1 is used in an automobile, the configuration of the airbag device 1 changes depending on whether the airbag device 1 is used in the driver's seat or the passenger seat of the automobile. Furthermore, the configuration of the airbag device 1 also changes depending on the positional relationship between the instrument panel to which the airbag device 1 is fixed and the occupant, the shape of the airbag cover provided on the instrument panel, the opening and closing method, etc. Therefore, the shape and dimensions of the main body portion 20, the number, shape, dimensions and positions of the exhaust ports 20a provided in the main body portion 20, the number, shape, dimensions and positions of the pipe portions 30, the number, shape, dimensions and positions of the ejection ports 30a provided in the pipe portions 30, etc. may be set appropriately depending on the usage manner of the airbag device 1.

[0071] [Variations] As described above, the configuration of the gas generator 10 including the main body portion 20, the outlet 20a, the pipe portion 30, and the ejection port 30a is set appropriately depending on the mode of use of the airbag device 1. Some of the different configuration examples of the gas generator 10 will be described below.

[0072] FIG. 8 is a diagram showing a different configuration example of the tubular portion 30. In the above example, one end of a circular tube is closed with a lid to form the tubular portion 30. However, as shown in FIG. 8, the tubular portion 30 may be formed from a rectangular thin metal plate. Specifically, as shown by the arrow in FIG. 8(a), a metal plate 130 having a nozzle 30a formed therein is rolled so that one edge 130a is located inside the opposing edge 130b, forming a tubular shape as shown in FIG. 8(b). Next, as shown by the arrow in FIG. 8(b), a portion of the one end is pressed radially to flatten it, forming a flat portion 130c as shown in FIG. 8(c). Next, as shown by the arrow in FIG. 8(c), a portion of the tip end of the flat portion 130c is bent to form a bent portion 130d as shown in FIG. 8(d), forming a closed end of the tubular portion 30. 8(d), a bent portion 130d and a portion 130e of the opening end portion or the like may be fixed by spot welding to prevent the tube from opening due to the pressure of the gas. In this manner, a thin flat plate may be processed to form a tube portion 30 having one end open and the other end closed, with an outlet 30a formed in the tube wall.

[0073] Fig. 9 is a diagram showing different examples of the outlet 20a formed in the peripheral wall of the main body 20. Fig. 9 shows only the upper part of the main body 20. In the above example, the main body 20 is provided with the outlet 20a in a perfect circle, but the outlet 20a may have a shape other than a perfect circle. For example, the outlet 20a may be elliptical, or may have a shape other than a circle, such as a substantially cross shape as shown in Fig. 9(a).

[0074] Furthermore, in the above-described example, one through-hole is provided as the discharge outlet 20a corresponding to each pipe portion 30, but the discharge outlet 20a may be configured with a plurality of through-holes. For example, as shown in FIG. 9(b), the discharge outlet 20a may be configured with a plurality of through-holes having a perfect circular shape. Each through-hole may have a shape other than a perfect circle. For example, as shown in FIG. 9(c), the discharge outlet 20a may be configured with a plurality of elongated holes extending in the circumferential direction (lateral direction) in the peripheral wall portion of the main body portion 20. Each elongated hole may be formed elongated in the axial direction (vertical direction) of the main body portion 20. The plurality of through-holes constituting the discharge outlet 20a may include through-holes having shapes different from the others.

[0075] Furthermore, in the above-described example, a plurality of discharge ports 20a are provided at different positions in the circumferential direction with the same height in the axial direction of the substantially cylindrical main body 20, but one or more discharge ports 20a with different heights in the axial direction of the cylinder may be provided. The number of discharge ports 20a provided in the main body 20 is not particularly limited. The area of ​​each discharge port 20a is not limited to a case where it is larger than the total area of ​​the ejection ports 30a formed in the pipe portion 30 corresponding to the discharge port 20a, and the area of ​​each discharge port 20a may be the same as or smaller than the total area of ​​the ejection ports 30a.

[0076] Similarly, the ejection ports 30a provided in the pipe section 30 may have a shape other than a perfect circle, and each ejection port 30a may be formed by a plurality of through holes. The ejection ports 30a are not limited to being arranged linearly in the axial direction of the pipe section 30, and may be arranged such that one or a plurality of ejection ports 30a are provided at different circumferential positions on the pipe wall. For example, the ejection ports 30a may be arranged in a staggered pattern with different circumferential positions. The number of ejection ports 30a provided in the pipe section 30 is also not particularly limited.

[0077] 10A and 10B are diagrams showing different examples of the cross-sectional shape of the pipe portion 30. In the above-described example, the cross-section of the pipe portion 30 has a perfect circular shape, but the cross-sectional shape of the pipe portion 30 is not limited to a perfect circular shape. For example, as shown in FIG. 10A, the cross-sectional shape may be an ellipse that is elongated in the circumferential direction (horizontal direction) of the peripheral wall of the main body portion 20, or as shown in FIG. 10B, the cross-sectional shape may be an ellipse that is elongated in the axial direction (vertical direction) of the main body portion 20.

[0078] In the above example, the pipe portion 30 is provided with the outlet 30a that ejects gas in an upward direction, but as shown in Fig. 10(c), the outlet 30a may be provided so as to eject gas in a direction other than the upward direction. The direction of the outlet 30a may be set in accordance with the ejection direction of gas required to inflate and deploy the airbag 200.

[0079] In the above-described example, a plurality of ejection ports 30a are provided at positions spaced apart in the axial direction in the pipe wall of the pipe section 30. However, as shown in Fig. 10(d), a plurality of ejection ports 30a may be provided at positions spaced apart in the circumferential direction. As shown in Fig. 10(d), a plurality of ejection ports 30a spaced apart in the circumferential direction may be defined as one set, and multiple sets may be provided spaced apart in the axial direction. Furthermore, when providing a plurality of ejection ports 30a, the ejection ports 30a are not limited to being provided at equal intervals, and may include ejection ports 30a provided at different intervals, or all of the ejection ports 30a may be provided at unequal intervals.

[0080] 11 and 12 are diagrams showing examples of different shapes of the pipe portion 30 and different positional relationships with the main body portion 20. Note that in Figs. 11 and 12, only the gas generator 10 is shown, the shape of the airbag case 40 is shown in a dashed rectangular frame, and other configurations are not shown.

[0081] In the above example, the pipe section 30 has a straight pipe shape with a linear axis, but as shown in Fig. 11(a), the pipe section 30 may have a curved pipe shape with a curved axis. As shown in Fig. 11(b), the pipe section 30 may have a straight axis but bend midway. That is, the pipe section 30 may have a shape formed by connecting multiple straight pipes. The pipe section 30 may also have an embodiment including a straight pipe portion and a curved pipe portion.

[0082] In the above example, the pipes 30 are arranged so that each pipe extends radially from the center of the main body 20 and the spacing between adjacent pipes 30 increases with increasing distance from the main body 20. However, as shown in FIG. 11(c), the pipes 30 may be arranged so that the spacing between two adjacent pipes 30 is constant. For example, two pipes 30 may be arranged so that their axial directions are parallel, forming an "E" shape when viewed from above. As shown in FIG. 11(d), the main body 20 may have a cylindrical shape, and four pipes 30 may be arranged at 90-degree intervals around the cylindrical axis. For example, two of the four pipes 30 may be arranged parallel to the long sides of the airbag case 40 and the remaining two parallel to the short sides, forming a cross shape when viewed from above.

[0083] As shown in Figure 11(d), the multiple pipe sections 30 may include pipe sections 30 with different axial lengths, or may include pipe sections 30 with different numbers of nozzles 30a provided therein.

[0084] Although the above-described example shows an example in which four pipe sections 30 are used, it is also possible to use three or fewer pipe sections 30, or five or more pipe sections 30. For example, as shown in Fig. 12(a), it is also possible to provide pipe sections 30 extending in three directions from the main body section 20 so that their positional relationship when viewed from above is Y-shaped, or as shown in Fig. 12(b), it is also possible to provide pipe sections 30 extending in two directions from the main body section 20 so that their positional relationship when viewed from above is linear.

[0085] In the above-described example, the main body 20 is disposed in the center of the bottom surface of the airbag case 40, and a plurality of pipe sections 30 are provided extending outward in multiple directions. However, as shown in Fig. 12(c), an embodiment is also possible in which the main body 20 is disposed close to one side of the airbag case 40, and a plurality of pipe sections 30 are provided so as to extend in one direction from the main body 20. In other words, an embodiment is also possible in which a plurality of pipe sections 30 are provided extending from the main body 20 disposed on one side in the longitudinal direction (X-axis direction) of the rectangular bottom surface to the other side in the longitudinal direction.

[0086] In the above example, each pipe 30 is formed from a single pipe, but as shown in Fig. 12(d), the pipe 30 may be branched into multiple parts midway. The pipe 30 may be branched into a T-shape or a Y-shape. The pipe 30 may be branched into three or more parts midway, or may be branched into multiple branch-like locations.

[0087] In the above example, the tube portion 30 is fixed to the main body portion 20 at one axial end so as to include the outlet 20a of the main body portion 20 inside the tube, while the other axial end is closed by a lid. However, the tube portion 30 may alternatively have an outlet 30a formed in the lid, or may have no lid and the other axial end is open.

[0088] In the above example, a gas generating agent is burned inside the main body 20 to generate gas, but as long as the gas generated in the main body 20 can be ejected using the tube 30, the method of generating gas is not particularly limited, and gas may be generated in a different manner.

[0089] The above has described embodiments of the gas generator 10 and the airbag device 1 according to the present disclosure with reference to the drawings, but the configurations and operations of the gas generator 10 and the airbag device 1 are not limited to the above-described embodiments, and may be implemented in various forms with various improvements, changes, and modifications made based on the knowledge of those skilled in the art, within the scope that does not deviate from the spirit of the invention. [Industrial Applicability]

[0090] The gas generator and airbag device according to the present invention are useful for lowering the temperature of gas ejected from the gas generator. [Explanation of symbols]

[0091] 1 Airbag device 10 Gas Generator 20 Main body 20a outlet 20b Flange part 20c fixing hole 30 Pipe section 30a spout 30b One axial closed end 40 Airbag Case 40a opening 40b fixing hole 40c through hole 50 retainer 51 Base material 51a, 51b through hole 51c Groove 52 volts 62 Nut 130 Metal plate 130a, 130b edges 130c flat part 130d bent part 200 airbags 300 insertion slot 300a circular section 300b slit section 301 Fixed hole

Claims

1. A gas generator that generates gas to inflate and deploy an airbag, a main body having a cylindrical shape and discharging gas generated therein from an outlet provided in a peripheral wall of the cylindrical shape; a tubular section having a tubular shape, the tubular section being fixed at a predetermined position relative to the main body section with the inside of the tubular section communicating with the inside of the main body section via the exhaust port, the tubular section receiving the gas exhausted from the exhaust port into the inside of the tubular section and ejecting the gas from an ejection port provided at a position separated from the exhaust port; A gas generator comprising:

2. 2. The gas generator according to claim 1, wherein an area of ​​the ejection port formed in the tube portion is smaller than an area of ​​the exhaust port formed in the main body portion.

3. 2. The gas generator according to claim 1, wherein the pipe portion is fixed to correspond to the exhaust port in a positional relationship in which the direction of gas exhaust from the exhaust port is the axial direction of the tubular shape.

4. An airbag device that inflates and deploys a folded airbag, Airbags and a gas generator according to any one of claims 1 to 3, which generates gas for inflating and deploying the airbag; an airbag case that houses the gas generator and the folded airbag; An airbag device comprising:

5. a retainer for holding the main body and the pipe of the gas generator in a predetermined positional relationship; 5. The airbag device according to claim 4, further comprising:

6. an opening is formed in the airbag, which allows the pipe portion of the gas generator and the retainer to be inserted into the airbag after the pipe portion is fixed to the retainer; The opening has a shape including a slit portion that expands a part of a shape formed to fit the main body of the gas generator so that the retainer to which the tube portion is fixed can be inserted.

6. The airbag device according to claim 5.

7. the retainer, to which the pipe portion of the gas generator is fixed at a predetermined position, is inserted into the airbag together with the pipe portion through an opening of the airbag, and is housed together with the airbag in the airbag case; the gas generator, a part of the main body of which is inserted into the airbag from outside the airbag case through an opening formed in the airbag case; The retainer is fixed to a predetermined position of the airbag case, with the inside of the pipe portion fixed to the retainer in the airbag communicating with the inside of the main body portion through the exhaust port provided in the main body portion.

6. The airbag device according to claim 5.

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