Gas generator and lock release device

Abstract

To provide a gas generator with improved assembly strength of the holder and cup. [Solution] The gas generator 1 comprises a cup 40 and a holder 10 to which it is mounted coaxially. The cylindrical portion 41 of the cup 40 has a flange portion 43 extending outward from the open end. The axial end face of the holder 10 facing the cup 40 is provided with an annular groove portion 16 for receiving the flange portion 43 and an annular flange portion 17. The flange portion 43 includes a first surface 43a facing the bottom surface of the annular groove portion 16 and a second surface 43b located on the opposite side. The second surface 43b includes an inclined surface that slopes away from the first surface 43a as it moves from the radially outer side of the cylindrical portion 41 towards the inside. The entire portion included in the first surface 43a that overlaps with the inclined surface when viewed along the axial direction of the cylindrical portion 41 has a planar shape perpendicular to the axial direction of the cylindrical portion 41.

Description

Technical Field

[0001] The present invention relates to a gas generator and a locking release device, and particularly to a gas generator and a locking release device configured to be suitably used for control during the deployment and contraction operations of an automotive airbag or the like.

Background Art

[0002] Conventionally, from the viewpoint of protecting passengers in vehicles and the like, airbag devices and seat belt devices, which are passenger protection devices, have become widespread. An airbag device is equipped for the purpose of protecting a passenger from the impact generated during a vehicle collision or the like, and instantaneously inflates and deploys an airbag during a vehicle collision or the like, and this serves as a cushion to receive the passenger's body. A seat belt device is equipped for the purpose of protecting a passenger from the impact generated during a vehicle collision or the like, and restrains the passenger to the seat by winding a belt around the passenger's body.

[0003] In recent airbag devices, in order to enhance the impact absorption force of the airbag on the passenger, attempts have been made to control the shape of the airbag or control the hardness (softness) of the airbag during the inflation and deployment of the airbag. These shape control and hardness control of the airbag are achieved by incorporating various mechanical and electrical elements into the airbag device. Among them, there is one that uses a locking release device capable of instantaneously releasing the locked state.

[0004] As documents that disclose an airbag device provided with a locking release device for controlling the shape of an airbag, for example, Japanese Patent Application Laid-Open No. 2009-293785 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2020-32981 (Patent Document 2) are known. In the locking release devices disclosed in these documents, a gas generator is used to instantaneously release the locked state of a belt extending from the airbag. In the locking release devices disclosed in these documents, by utilizing the pressure generated when this gas generator operates, it becomes possible to release the locked state of the belt very quickly and with good responsiveness.

[0005] On the other hand, gas generators are sometimes incorporated into seat belt systems equipped with so-called pretensioners. A pretensioner is a device that instantly tightens the seat belt when a collision with a vehicle is detected, compensating for slack in the seat belt caused by the thickness of clothing, etc. This function is achieved by the strong pulling of one end of the seat belt by the pressure of the gas output from the gas generator. Examples of documents disclosing this type of gas generator include Japanese Patent Application Publication No. 2008-37389 (Patent Document 3).

[0006] The gas generators disclosed in the above-mentioned Patent Documents 1 to 3 comprise a cup and a holder that holds an igniter and to which the cup is assembled. The cup is assembled to the holder by a so-called crimping method.

[0007] In detail, the open end of the cup is provided with a flange portion extending outward, and the axial end of the holder on the cup side is provided with an annular flange portion. The annular flange portion is bent inward to lock the flange portion, thereby fixing the cup to the holder. [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2009-293785 [Patent Document 2] Japanese Patent Publication No. 2020-32981 [Patent Document 3] Japanese Patent Publication No. 2008-37389 [Overview of the project] [Problems that the invention aims to solve]

[0009] In this type of gas generator, it is important that the cup is firmly attached to the holder. This is because the cup must not detach from the holder even due to the increase in internal pressure during operation. Furthermore, ensuring sufficient assembly strength between the holder and the cup is also important from the standpoint of achieving stable operation of the locking release device equipped with the gas generator.

[0010] Therefore, the present invention has been made to solve the above-mentioned problems, and aims to provide a gas generator with improved assembly strength of the holder and cup, and a locking release tool equipped therewith. [Means for solving the problem]

[0011] A gas generator according to the present invention comprises an igniter, a cup, and a substantially cylindrical holder. The igniter has an ignition section loaded with an igniter and a terminal pin connected to the ignition section. The cup has a bottomed, substantially cylindrical portion including a cylindrical section and a closing section that closes one end of the cylindrical section. The holder closes the open end of the cylindrical section by being assembled coaxially with the cup, and holds the igniter such that the ignition section faces the closing section. The cylindrical section has a flange section extending outward from the open end. The axial end face of the holder facing the cup is provided with an annular groove for receiving the flange section and an annular flange section defining the outer wall surface of the annular groove section. The flange section includes a first surface facing the bottom surface of the annular groove section and a second surface located on the opposite side of the first surface. The second surface includes an inclined surface that slopes away from the first surface as it moves from the outside to the inside in the radial direction of the cylindrical section. With the flange portion received by the annular groove portion, the annular flange portion is bent inward, causing the tip of the annular flange portion to contact the inclined surface. As a result, the flange portion is sandwiched between the tip of the annular flange portion and the bottom surface of the annular groove portion in the axial direction of the cylindrical portion, thereby assembling the cup to the holder. The entire portion included in the first surface that overlaps with the inclined surface when viewed along the axial direction of the cylindrical portion has a planar shape perpendicular to the axial direction of the cylindrical portion.

[0012] The lock release device according to the present invention comprises a gas generator according to the present invention, and is configured such that the lock on a locked portion is released when the gas generator is activated. The lock release device further comprises a housing having a through hole in its wall. A locking pin for locking the locked portion is erected in the closing portion, facing away from the holder side. The gas generator is housed inside the housing such that the locking pin is inserted through the through hole, allowing the locked portion to be locked by the locking pin located outside the housing. In the lock release device according to the present invention, when the gas generator is activated, the pressure in the space outside the gas generator and inside the housing increases, causing the gas generator to move away from the wall of the portion with the through hole, and thereby the locking pin is pulled into the housing, releasing the lock on the locked portion. [Effects of the Invention]

[0013] According to the present invention, it is possible to provide a gas generator in which the assembly strength of the holder and cup is improved, and a locking release tool equipped therewith. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic cross-sectional view of a gas generator according to an embodiment. [Figure 2] Figure 1 is a perspective view of the cup shown. [Figure 3] This is an enlarged cross-sectional view of region III shown in Figure 1. [Figure 4] This is a schematic cross-sectional view illustrating the operation of a lock release device equipped with a gas generator, as shown in Figure 1. [Figure 5] This is an enlarged cross-sectional view of the gas generator according to Comparative Example 1. [Figure 6] This is an enlarged cross-sectional view of the gas generator according to Comparative Example 2. [Figure 7] This is a schematic diagram of the simulation model for the embodiment. [Figure 8]It is a schematic diagram showing the stress distribution in the embodiment. [Figure 9] It is a schematic diagram showing the stress distribution in the embodiment. [Figure 10] It is a schematic diagram showing the stress distribution in Comparative Example 1. [Figure 11] It is a schematic diagram showing the stress distribution in Comparative Example 1. [Figure 12] It is a schematic diagram showing the stress distribution in Comparative Example 2. [Figure 13] It is a schematic diagram showing the stress distribution in Comparative Example 2.

Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The embodiments shown below exemplify the case where the present invention is applied to a locking release tool provided in an airbag device and a gas generator preferably incorporated in the locking release tool. In the embodiments shown below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

[0016] (Embodiment) <A. Configuration of Gas Generator> FIG. 1 is a schematic cross-sectional view of a gas generator according to an embodiment. FIG. 2 is a perspective view of the cup shown in FIG. 1. FIG. 3 is an enlarged cross-sectional view of region III in FIG. 1. First, referring to FIGS. 1 to 3, the configuration of the gas generator 1 according to the present embodiment will be described. The configuration of the locking release tool 100 including the gas generator 1 will be described in detail later.

[0017] As shown in FIGS. 1 to 3, the gas generator 1 according to the present embodiment mainly includes a holder 10, an igniter 20, a seal member 30, and a cup 40.

[0018] The holder 10 and the cup 40, when assembled coaxially, constitute the housing that forms the outer shell of the gas generator 1. The igniter 20 is held by the holder 10. The cup 40 is mounted on the holder 10 so as to cover the igniter 20.

[0019] The holder 10 is a component for holding the igniter 20 and the cup 40, and has a substantially cylindrical shape. In this embodiment, the holder 10 is provided with a first recess 12, a second recess 13, and an opening 14a, so the holder 10 has a substantially cylindrical shape. The first recess 12, the second recess 13, and the opening 14a will be described later.

[0020] The holder 10 is made of a molded product made of a metal material such as aluminum or an aluminum alloy. The holder 10 is formed into the shape shown in the figure by performing forging, punching, cutting, etc., on a plate-shaped metal member or rod-shaped metal member, for example, one or more times in a predetermined order.

[0021] The holder 10 has a cylindrical body portion 11 that defines its outer circumferential surface, and this body portion 11 is provided with a first recess 12 and a second recess 13. A partition portion 14 is formed in the portion of the body portion 11 located between the first recess 12 and the second recess 13 so as to separate the first recess 12 and the second recess 13. A locking portion 15 is formed in the portion of the body portion 11 located on the side of the cup 40's closing portion 42, which will be described later, from the partition portion 14.

[0022] The first recess 12 is a portion for receiving and holding the base 21 of the igniter 20, which will be described later, and is provided on the axial end face of the body 11 facing the cup 40. The bottom surface of the first recess 12 is defined by the partition 14. The inner surface of the first recess 12 is mainly defined by the locking portion 15.

[0023] The second recess 13 is a portion where a pair of terminal pins 23 of the igniter 20, described later, are arranged, and where a connector (not shown) for external connection of the igniter 20 via the pair of terminal pins 23 is provided. The second recess 13 is provided on the axial end face of the body portion 11 that does not face the cup 40. The bottom surface of the second recess 13 is defined by the partition portion 14. The inner surface of the second recess 13 is defined by the cylindrical portion of the body portion 11.

[0024] The partition portion 14 is provided with an opening 14a that connects to the first recess 12 and the second recess 13. The opening 14a is the portion through which a pair of terminal pins 23 are inserted (more precisely, the portion into which the pair of terminal pins 23 and the lower end of the base 21 of the igniter 20 that covers them are fitted).

[0025] The locking portion 15 is a part for crimping and fixing the base portion 21 of the igniter 20, and has an annular plate shape. The tip of the locking portion 15 is bent inward, thereby fixing the igniter 20 housed in the first recess 12 to the holder 10 so that it cannot move.

[0026] As shown in Figures 1 and 3, an annular groove 16 and an annular flange 17 are provided on the axial end face of the body portion 11 facing the cup 40, surrounding the locking portion 15 described above.

[0027] The annular groove 16 is a portion for receiving and holding the flange portion 43 of the cup 40, which will be described later, inserted along the axial direction.

[0028] The annular flange portion 17 is a part for crimping and fixing the flange portion 43 of the cup 40, and has an annular plate shape that protrudes from the body portion 11 toward the closing portion 42 of the cup 40 so as to define the outer wall surface of the annular groove portion 16. The tip portion of the annular flange portion 17 is bent inward, thereby fixing the cup 40 to the holder 10 so that it cannot move.

[0029] The igniter 20 is used to generate a flame and is also called a squib. The igniter 20 has a base 21, an ignition part 22, and a pair of terminal pins 23. The base 21 is the part that holds the ignition part 22 and the pair of terminal pins 23, and is also the part that is fixed to the holder 10. The base 21 holds the pair of terminal pins 23 by inserting them through it. Note that in Figure 1, the pair of terminal pins 23 are positioned overlapping in a direction perpendicular to the plane of the paper, so only one of them is visible.

[0030] The ignition unit 22 contains an igniter that generates a flame when ignited and burned during operation, and a resistor (bridge wire) for igniting the igniter. A pair of terminal pins 23 are connected to the ignition unit 22 to ignite the igniter.

[0031] In detail, the ignition unit 22 includes a cup-shaped squib cup, and the aforementioned resistor is attached to connect the tips of a pair of terminal pins 23 inserted into the squib cup, with an igniter loaded into the squib cup so as to surround or be close to the resistor.

[0032] Nichrome wire is generally used as the resistor, and as the ignition agent, for example, ZPP (zirconium potassium perchlorate), ZWPP (zirconium tungsten potassium perchlorate), or lead tricinate are used. The squib cup mentioned above is made of metal or plastic, for example.

[0033] When a collision is detected, a predetermined amount of current flows through the resistor via terminal pin 23. This current generates Joule heat within the resistor, causing the igniter to begin burning. The resulting high-temperature flame ruptures the squib cup containing the igniter. The time from when current flows through the resistor until the igniter 20 activates is generally 2ms or less when a nichrome wire is used for the resistor.

[0034] When assembling the igniter 20 to the holder 10, the igniter 20 is inserted into the first recess 12 from the axial end of the holder 10 on the side where the first recess 12 is provided, such that the pair of terminal pins 23 are inserted into the opening 14a provided in the partition portion 14. As a result, the base portion 21 is housed in the first recess 12 and the opening 14a, and the pair of terminal pins 23 are positioned in the second recess 13. In this state, the tip portion of the locking portion 15 is bent toward the base portion 21. As a result, the base portion 21 is clamped between the partition portion 14 and the locking portion 15, thereby crimping and fixing the igniter 20 to the holder 10.

[0035] Therefore, the ignition portion 22 of the igniter 20 is located on the side of the cup 40 that will be described later, closer to the closing portion 42, than the axial end face of the holder 10 on the side where the first recess 12 is provided, and the ignition portion 22 faces the closing portion 42.

[0036] A sealing member 30, such as an O-ring, is pre-installed in the first recess 12 of the holder 10. The gap between the holder 10 and the igniter 20 is sealed by the sealing member 30. Specifically, the sealing member 30 is positioned between the partition portion 14 and the locking portion 15 of the holder 10 and the base portion 21 of the igniter 20. The sealing member 30 is compressed by the holder 10 and the igniter 20, thereby ensuring a seal between them.

[0037] Furthermore, it is preferable to use a material with sufficient heat resistance and durability as the sealing member 30. For example, an O-ring made of EPDM, a type of ethylene propylene rubber, can be suitably used.

[0038] As shown in Figures 1 to 3, the cup 40 has a bottomed, substantially cylindrical portion that includes a cylindrical portion 41 and a closing portion 42 that closes one end of the cylindrical portion 41. The ignition portion 22 of the igniter 20 is located in the housing space 44 of the cup 40, which is defined by the cylindrical portion 41 and the closing portion 42.

[0039] The cylindrical portion 41 has a flange portion 43 that extends outward from its open end. The flange portion 43 is the part that secures the cup 40 to the holder 10.

[0040] The flange portion 43 includes a first surface 43a and a second surface 43b located on the opposite side of the first surface 43a. The first surface 43a is the portion facing the bottom surface of the annular groove portion 16. The second surface 43b includes an inclined surface that slopes away from the first surface 43a as it moves from the outside to the inside in the radial direction of the cylindrical portion 41.

[0041] The corner 45 located between the first surface 43a and the inner circumferential surface of the cylindrical portion 41 is formed as a curved surface that is smoothly continuous with any of these adjacent surfaces. This reduces stress concentration at the corner 45 when the gas generator 1 is in operation. Note that the corner 45 does not necessarily have to be formed as a curved surface; for example, it may be formed as a substantially right-angled surface.

[0042] As shown in Figure 2, the closed portion 42 is provided with an ejection hole 42a that penetrates it. The ejection hole 42a is for guiding the gas generated when the gas generator 1 is operating to the outside of the housing. The number of ejection holes 42a is not particularly limited and may be one or more. In this embodiment, two ejection holes 42a are provided in the closed portion 42 so as to be positioned at 180° rotationally symmetrical positions when viewed along the axial direction of the cylindrical portion 41.

[0043] A locking pin 42b is erected in the closing portion 42, facing away from the holder 10. The locking pin 42b is for locking the part to be locked, which will be described later. The locking pin 42b may be solid or hollow.

[0044] The cup 40 is a component that forms part of the housing and is made of a molded product made of a metal material such as an iron-based material including stainless steel, aluminum, or an aluminum alloy. Generally, press working using a die is used to form the cup 40. In this embodiment, an aluminum cup 40 is used. This makes it possible to reduce manufacturing costs compared to when the cup 40 is made of an iron-based material.

[0045] As described above, the cup 40 is assembled to the holder 10 by crimping and fixing the flange portion 43 to the holder 10 by the annular flange portion 17 provided on the holder 10.

[0046] In detail, first, the flange portion 43 of the cup 40 is received in the annular groove portion 16 provided in the holder 10. As a result, as shown in Figure 3, the first surface 43a of the flange portion 43 of the cup 40 comes into contact with the bottom surface of the annular groove portion 16. At this time, the inner circumferential surface of the cylindrical portion 41 of the cup 40 may or may not come into contact with the inner wall surface of the annular groove portion 16.

[0047] Next, with the flange portion 43 of the cup 40 received in the annular groove portion 16 of the holder 10, the annular flange portion 17 of the holder 10 is bent inward. As a result, the tip portion of the annular flange portion 17 comes into contact with the second surface 43b of the flange portion 43.

[0048] As a result, the flange portion 43 is sandwiched between the tip portion of the annular flange portion 17 and the bottom surface of the annular groove portion 16 in the axial direction of the cylindrical portion 41, thereby assembling the cup 40 to the holder 10. Consequently, the open end of the cylindrical portion 41 of the cup 40 is closed by the holder 10 (or more precisely, by the igniter 20 in addition to the holder 10).

[0049] Here, as shown in FIG. 3, the entire portion included in the first surface 43a of the flange portion 43 of the cup 40 and overlapping the inclined surface of the second surface 43b when viewed along the axial direction of the cylindrical portion 41 has a planar shape orthogonal to the axial direction of the cylindrical portion 41. By configuring in this way, the assembling strength of the holder 10 and the cup 40 can be improved, and this point will be described in detail later.

[0050] <B. Configuration and Operation of the Lock Release Device> FIG. 4 is a schematic cross-sectional view for explaining the operation of the lock release device including the gas generator shown in FIG. 1. Specifically, FIG. 4(A) is a schematic cross-sectional view showing the state before the operation of the lock release device. FIG. 4(B) is a schematic cross-sectional view showing the state after the operation of the lock release device. Next, referring to FIG. 4, the configuration of the lock release device 100 in the present embodiment and the operation during the operation of the lock release device 100 will be described.

[0051] As shown in FIGS. 4(A) and 4(B), the lock release device 100 is configured to maintain the state of locking the locked portion before the operation of the gas generator 1 and to release the locking to the locked portion when the gas generator 1 operates. Various structures can be applied as the locked portion, but in the present embodiment, the case where the loop-shaped portion provided on the belt 80 extending from the airbag corresponds to the locked portion is exemplified.

[0052] The lock release device 100 includes a gas generator 1 and a container 110 that houses the gas generator 1 inside. The container 110 has a substantially cylindrical shape with one end in the axial direction substantially closed. Note that the shape of the container 110 is not particularly limited to this and can be appropriately changed.

[0053] The container 110 has a side wall portion 111 and a wall portion 112 that closes one end of the side wall portion 111 in the axial direction. The wall portion 112 is provided with a through hole 112a through which the locking pin 42b provided on the closing portion 42 of the cup 40 can be inserted.

[0054] The gas generator 1 is positioned inside the container 110 such that a locking pin 42b is inserted through a through hole 112a in the wall portion 112 from the inside out. The open axial end of the side wall portion 111 is bent inward after the gas generator 1 is positioned to form a stopper portion 113.

[0055] Furthermore, a first seal ring and a second seal ring, for example, made of an O-ring, may be housed inside the container 110. Specifically, the first seal ring may be positioned to seal the gap between the closing portion 42 of the cup 40 and the wall portion 112 of the container 110, and the gap between the locking pin 42b and the through hole 112a of the wall portion 112. The second seal ring may be positioned to seal the gap between the cylindrical portion 41 of the cup 40 and the side wall portion 111 of the container 110. By arranging the first seal ring and the second seal ring in a compressed state as described above, the sealing performance between each of the above-mentioned components can be ensured.

[0056] Referring to Figure 4(A), in the state before operation of the gas generator 1, the loop-shaped portion of the belt 80 is locked by the locking pin 42b located outside the container 110.

[0057] Referring to Figure 4(B), if a vehicle equipped with the gas generator 1 is involved in a collision, the collision is detected by a collision detection means separately provided on the vehicle, and the igniter 20 is activated based on this. When the igniter 20 is activated, the igniter contained in the ignition unit 22 is ignited and burns, generating gas, which causes the squib cup to rupture.

[0058] The gas generated by the combustion of the ignition charge is ejected to the outside of the housing of the gas generator 1 through the ejection holes 42a provided in the blocking portion 42 (see FIG. 2) (see the arrow G in FIG. 4(B)). As a result, the pressure in the space outside the gas generator 1 and inside the container 110 rapidly increases, causing the gas generator 1 to move in a direction away from the wall portion 112 of the portion where the through hole 112a is provided (that is, downward in the figure) (see the arrow D in FIG. 4(B)). The movement of the gas generator 1 is stopped when the bottom surface of the annular protrusion 11a protruding outward from the body portion 11 of the holder 10 abuts against the stopper portion 113.

[0059] As described above, when the gas generator 1 moves, the locking pin 42b is drawn into the container 110, thereby releasing the locking of the locking pin 42b to the loop-shaped portion of the belt 80. As a result, the inflation restraint of the airbag by the belt 80 is released, and the shape of the airbag during inflation and deployment is controlled.

[0060] <C. Parentheses> Here, when the gas generator 1 operates (specifically, when the igniter 20 operates), a load is applied to the caulked portion (see FIG. 3 etc.), which is the assembled portion of the cup 40 and the holder 10, in the direction along the axial direction of the cylindrical portion 41 and in the direction in which the cup 40 separates from the holder 10. If the assembling strength of the cup 40 and the holder 10 in the caulked portion is insufficient, the tip of the flange portion 43 of the cup 40 is deformed so as to face the side opposite to the blocking portion 42 side of the cup 40 in the axial direction (that is, downward in FIG. 3), and thereby the flange portion 43 comes out of the annular groove portion 16 of the holder 10. Such deformation is more likely to occur significantly when the cup 40 is made of a material such as aluminum, which generally has a lower strength than iron-based materials.

[0061] In this regard, in the gas generator 1 according to this embodiment, as described above, the second surface 43b of the flange portion 43 of the cup 40 includes an inclined surface that slopes away from the first surface 43a as it moves from the outside to the inside in the radial direction of the cylindrical portion 41 of the cup 40. Furthermore, the entire portion of the flange portion 43 that is included in the first surface 43a and overlaps with the inclined surface of the second surface 43b when viewed along the axial direction of the cylindrical portion 41 has a planar shape perpendicular to the axial direction of the cylindrical portion 41.

[0062] By configuring it in this way, the thickness of the flange portion 43 can be made sufficiently large. As a result, sufficient mechanical strength of the flange portion 43 is ensured, which suppresses deformation of the flange portion 43 as described above, and thus effectively prevents the flange portion 43 from coming out of the annular groove portion 16.

[0063] Furthermore, with this configuration, even if the flange portion 43 deforms as described above, the dimension of the deformed flange portion 43 in the direction perpendicular to the axial direction can be made considerably larger than the size of the gap C (see Figure 3) between the tip of the annular flange portion 17 of the holder 10 and the base portion of the locking portion 15. This more effectively prevents the flange portion 43 from coming out of the annular groove portion 16.

[0064] Therefore, by using the gas generator 1 as in this embodiment, it is possible to create a gas generator with improved assembly strength of the holder and cup. Furthermore, by using a locking release device 100 equipped with such a gas generator 1, it is possible to create a locking release device that can achieve stable operation.

[0065] Furthermore, in the gas generator 1 according to this embodiment, as described above, the tip portion of the annular flange portion 17 of the holder 10 abuts against the second surface 43b of the flange portion 43. By increasing the contact area between the annular flange portion 17 and the second surface 43b in this way, the resistance to the rotational torque generated along the circumferential direction of the cylindrical portion 41 when the gas generator 1 is operating can be increased, and the rotation of the cup 40 relative to the holder 10 can be suppressed. In addition, the sealing performance between the annular flange portion 17 and the second surface 43b can also be improved.

[0066] The shape of the flange portion 43 in the above-described embodiment will be explained in detail below, in comparison with the flange portion 43X in Comparative Example 1 and the flange portion 43Y in Comparative Example 2. Figure 5 is an enlarged cross-sectional view of the gas generator 1X according to Comparative Example 1. Figure 6 is an enlarged cross-sectional view of the gas generator 1Y according to Comparative Example 2. Here, Figures 5 and 6 are diagrams showing cross-sections of the gas generators 1X and 1Y in the regions corresponding to Figure 3, respectively.

[0067] In addition, the gas generator 1X according to Comparative Example 1 differs from the gas generator 1 according to this embodiment only in the shape of the flange portion of the cup; the rest of its configuration is the same. The gas generator 1Y according to Comparative Example 2 differs from the gas generator 1 according to this embodiment only in the shape of the flange portion of the cup and the shape of the annular groove portion of the holder; the rest of its configuration is the same. Specifically, in the gas generator 1Y, the curvature of the corner portion located between the bottom surface and the inner wall surface of the annular groove portion is smaller than the curvature of the same portion in the gas generator 1.

[0068] First, with reference to Figures 3 and 5, we will compare the shape of the flange portion 43 in this embodiment with the shape of the flange portion 43X in Comparative Example 1.

[0069] The flange portion 43X differs from the flange portion 43 in that its second surface 43bX does not include an inclined surface and extends in a direction perpendicular to the axial direction of the cylindrical portion 41. Consequently, the thickness of the flange portion 43X is smaller than that of the flange portion 43. In other words, the flange portion 43 can have a sufficiently larger thickness than the flange portion 43X because its second surface 43b includes an inclined surface.

[0070] Furthermore, in the gas generator 1X, because the second surface 43bX of the flange portion 43X does not include an inclined surface, the bent annular flange portion 17 cannot fully follow the second surface 43bX, and a gap is easily created between them. As a result of this gap, deformation of the flange portion 43X is more likely to occur in the gas generator 1X.

[0071] In this regard, in the gas generator 1 according to this embodiment, as described above, the second surface 43b includes an inclined surface, which suppresses the occurrence of such a space. Therefore, this also prevents the flange portion from coming out of the annular groove.

[0072] Next, with reference to Figures 3 and 6, we will compare the shape of the flange portion 43 in this embodiment with the shape of the flange portion 43Y in Comparative Example 2.

[0073] The flange portion 43Y, like the flange portion 43, has a second surface 43bY that includes an inclined surface. On the other hand, in the flange portion 43Y, a portion of the part included in the first surface 43aY and which overlaps with the inclined surface of the second surface 43bY when viewed along the axial direction of the cylindrical portion 41 has a planar shape perpendicular to the axial direction of the cylindrical portion 41, while another portion of the overlapping part has a curved shape that moves away from the bottom surface of the annular groove portion 16 as it moves inward.

[0074] Due to having a curved shape in part like this, the thickness of the flange portion 43Y is configured to be smaller than the thickness of the flange portion 43. In other words, the flange portion 43 can ensure a thickness sufficiently larger than the thickness of the flange portion 43Y because the entire overlapping portion has a planar shape orthogonal to the axial direction.

[0075] Thus, it can be understood that by comparing with the gas generators 1X and 1Y according to Comparative Examples 1 and 2, when the gas generator 1 according to the above-described embodiment is used, a gas generator with improved assembling strength of the holder and the cup can be achieved.

[0076] The effect of improving the assembling strength of this holder and the cup has been confirmed by the simulation analysis, the first verification test, and the second verification test described later.

[0077] <D. Simulation Analysis> In the following, regarding the effect of improving the assembling strength of the holder and the cup obtained by configuring as in the gas generator 1 according to the present embodiment, an explanation will be given referring to the results of simulation analysis using the finite element method (FEM). FIG. 7 is a schematic diagram of the model according to the example. FIGS. 8 and 9 are schematic diagrams showing the stress distribution in the model according to the example. FIGS. 10 and FIG. 11 are schematic diagrams showing the stress distribution in the model according to Comparative Example 1. FIGS. 12 and 13 are schematic diagrams showing the stress distribution in the model according to Comparative Example 2. In FIGS. 7 to 13, the axial direction of the cup is taken as the Z direction, the direction orthogonal to the Z direction is taken as the X direction, and the direction orthogonal to both the Z direction and the X direction is taken as the Y direction. Also, in FIGS. 9, 11, and 13, only the cup is shown, and the illustration of the holder is omitted.

[0078] As shown in Figures 7 to 9, the model according to the embodiment is a simulation model that roughly corresponds to the holder 10 and cup 40 of the gas generator 1 according to the embodiment described above. The structural differences between the models of Comparative Examples 1 and 2 and the model according to the embodiment are the same as the differences between the gas generator 1 according to the embodiment described above and the gas generators 1X and 1Y according to Comparative Examples 1 and 2 (see Figures 3, 5, and 6). In addition, from the viewpoint of reducing the number of elements, this simulation model is constructed as a divided body in which the holder and cup are divided into four equal parts in the circumferential direction.

[0079] For the simulation analysis conditions, the material of the holder was set to aluminum (A6061-T6). The material of the cup was set to aluminum (A1070). The tensile strength of both aluminum (A6061-T6) and aluminum (A1070) was set to 340 MPa. In addition, a surface load of 500 N was set on the top surface of the cup, directed outward in the Z direction (upward in Figure 7) (see region AR1 and load F in Figure 7). This 500 N value was calculated based on a pressure that is 1 / 4 the magnitude of the pressure applied to the entire cup in an actual locking release device equipped with a gas generator. Furthermore, as a constraint condition, the surface of the holder exposed on the front side of the paper in Figure 7 (see region AR2 in Figure 7) was set to "fixed" in the X and Y directions. Furthermore, as a constraint, the bottom surface of the annular projection that protrudes outward from the body of the holder (see area AR3 in Figure 7) was "fixed" in all directions: X, Y, and Z. This is because when the locking release device is activated, the bottom surface of the annular projection comes into contact with the stopper portion of the housing, thereby stopping the movement of the gas generator (see Figure 4(B)).

[0080] The simulation analysis revealed that in both the example and Comparative Examples 1 and 2, the stress generated at the point where the tip of the annular flange of the holder of the cup makes contact tended to be greater than the stress generated at the rest of the cup. Furthermore, it was found that the stress generated in the cup in the example was generally reduced compared to the stress generated in the cup in Comparative Examples 1 and 2.

[0081] Furthermore, the maximum stress generated in the cup in the embodiment was 420 MPa (see position P1 in FIG. 9). The maximum stress generated in the cup in Comparative Example 1 was 1239 MPa (see position P2 in FIG. 11). The maximum stress generated in the cup in Comparative Example 2 was 960 MPa (see position P3 in FIG. 13). From these results, it was found that the maximum stress generated in the cup in the embodiment was reduced to less than half of the maximum stress generated in the cup in Comparative Examples 1 and 2.

[0082] From the above results, it was found that by configuring the gas generator 1 according to the present embodiment, the stress generated in the flange portion of the cup and its peripheral portion can be reduced.

[0083] <E. First Verification Test> In the first verification test, a so-called push-out test was performed on the gas generator 1 according to the embodiment and the gas generator 1X according to Comparative Example 1.

[0084] Specifically, first, a sample formed by caulking and fixing the holder and the cup constituting the gas generator 1 according to the embodiment, and a sample formed by caulking and fixing the holder and the cup constituting the gas generator 1X according to Comparative Example 1 were prepared. In these samples, the igniter was not assembled.

[0085] Next, in each sample, using a testing machine, an axial load was applied to the cup from the inside to the outside in a state where the holder was fixed in the axial direction. Next, this load was gradually increased, and the load applied to the cup when the cup came out of the holder was examined. The number of each sample in this verification test was one.

[0086] As a result of this verification test, in the gas generator 1X according to Comparative Example 1, it was confirmed that the cup came off the holder when a load of 2.8 kN was applied to the cup. On the other hand, in the gas generator 1 according to the present embodiment, it was confirmed that the cup came off the holder when a load of 3.6 kN was applied to the cup. From this result, it was confirmed that by using the gas generator 1 according to the present embodiment, the assembling strength of the holder and the cup can be improved as compared with the gas generator 1X according to the comparative example.

[0087] <F. Second Verification Test> In the second verification test, samples of the gas generator 1 according to the above-described embodiment and samples of the gas generator 1X according to Comparative Example 1 were prepared, and it was examined whether the cup came off the holder under the same pressure conditions as those in the actual products. The number of each sample in this verification test was three.

[0088] As a result of this verification test, in the gas generator 1X according to Comparative Example 1, it was confirmed that the cup came off the holder in all three samples. On the other hand, in the gas generator 1 according to the present embodiment, it was confirmed that the cup did not come off the holder in all three samples. From this result, it was confirmed that by using the gas generator 1 according to the present embodiment, the assembling strength of the holder and the cup can be improved as compared with the gas generator 1X according to the comparative example.

[0089] (Supplementary Note) Summarizing the characteristic configurations of the gas generator and the locking release tool disclosed in the above-described embodiment, it is as follows.

[0090] [Supplementary Note 1] An igniter having an ignition part filled with ignition powder and a terminal pin connected to the ignition part, A cup having a bottomed substantially cylindrical part including a cylindrical part and a closing part for closing one end of the cylindrical part, The cup is assembled coaxially to close the open end of the cylindrical portion, and the ignition part is held by a substantially cylindrical holder so that it faces the closed portion. The cylindrical portion has a flange portion extending outward from the open end, The axial end face of the holder facing the cup is provided with an annular groove for receiving the flange portion and an annular flange that defines the outer wall surface of the annular groove portion. The flange portion includes a first surface facing the bottom surface of the annular groove and a second surface located on the opposite side of the first surface. The second surface includes an inclined surface that slopes away from the first surface as it moves from the outside to the inside in the radial direction of the cylindrical portion. With the flange portion received by the annular groove portion, the annular flange portion is bent inward, causing the tip of the annular flange portion to contact the inclined surface, thereby sandwiching the flange portion between the tip of the annular flange portion and the bottom surface of the annular groove portion in the axial direction of the cylindrical portion, and thus the cup is assembled to the holder. A gas generator in which the entire portion included in the first surface and which overlaps with the inclined surface when viewed along the axial direction of the cylindrical portion has a planar shape perpendicular to the axial direction of the cylindrical portion.

[0091] [Note 2] The gas generator as described in Appendix 1, wherein the corner located between the first surface and the inner circumferential surface of the cylindrical part is a curved surface that is smoothly continuous with any of the adjacent surfaces.

[0092] [Note 3] The gas generator described in Appendix 1 or 2, wherein the above cup is made of aluminum.

[0093] [Note 4] A lock release device comprising a gas generator as described in any one of the appendices 1 to 3, wherein the lock on a locked portion is released when the gas generator is activated, The above-mentioned locking release device further comprises a housing with a through hole in the wall, A locking pin for locking the locked portion is erected in the above-mentioned closing portion, facing away from the holder side. The gas generator is housed inside the container such that the locking pin is inserted through the through hole, allowing the part to be locked to be locked by the locking pin located outside the container. A locking release device wherein, upon operation of the gas generator, the pressure in the space outside the gas generator and inside the containment increases, causing the gas generator to move away from the wall portion of the section with the through hole, thereby pulling the locking pin into the containment and releasing the lock on the locked portion.

[0094] (Other forms, etc.) The locking release device according to the above-described embodiment is not only applicable to the shape control of airbags, but can also be applied to the control of the opening and closing timing of airbag vent holes. Furthermore, it can be incorporated into devices other than airbag systems and can be used in a variety of applications as a component that instantly releases the locking of a locked part.

[0095] Furthermore, while the above-described embodiment illustrates the application of the present invention to a locking release device provided in an airbag system and a gas generator suitably incorporated into said locking release device, the present invention is not limited to such gas generators. For example, the present invention may be applied to a gas generator incorporated into a seat belt system equipped with a pretensioner.

[0096] Furthermore, the shape, configuration, size, number, material, etc., of each part shown in the embodiments of the present invention described above can be modified in various ways, as long as they do not depart from the spirit of the present invention.

[0097] Furthermore, the characteristic configurations shown in the embodiments of the present invention described above can naturally be combined with each other without departing from the spirit of the present invention.

[0098] Thus, the embodiments disclosed herein are illustrative in all respects and not restrictive. The technical scope of the present invention is defined by the claims and includes all modifications within the meaning and scope of equivalents to the claims. [Explanation of Symbols]

[0099] 1,1X,1Y Gas generator, 10 Holder, 11 Body, 11a Annular projection, 12 First recess, 13 Second recess, 14 Partition, 14a Opening, 15 Locking part, 16 Annular groove, 17 Annular flange, 20 Ignition device, 21 Base, 22 Ignition part, 23 Terminal pin, 30 Seal member, 40 Cup, 41 Cylindrical part, 42 Closure part, 42a Discharge hole, 42b Locking pin, 43 Flange part, 43a,43aY First surface, 43b,43bX,43bY Second surface, 43X,43Y Flange part, 44 Storage space, 45 Corner part, 80 Belt, 100 Locking release tool, 110 Housing, 111 Side wall, 112 Wall, 112a Through hole, 113 stopper section.

Claims

1. An igniter having an ignition section loaded with igniter powder and terminal pins connected to the ignition section, A cup having a cylindrical portion and a bottomed, substantially cylindrical portion including a closing portion that closes one end of the cylindrical portion, The cup is assembled coaxially to close the open end of the cylindrical portion, and the ignition part is held by a substantially cylindrical holder so that it faces the closed portion. The cylindrical portion has a flange portion extending outward from the open end, The axial end face of the holder facing the cup is provided with an annular groove for receiving the flange portion and an annular flange that defines the outer wall surface of the annular groove portion. The flange portion includes a first surface facing the bottom surface of the annular groove portion and a second surface located on the opposite side of the first surface. The second surface includes an inclined surface that slopes away from the first surface as it moves from the outside to the inside in the radial direction of the cylindrical portion. With the flange portion received by the annular groove portion, the annular flange portion is bent inward, so that the tip portion of the annular flange portion comes into contact with the inclined surface, and thereby the flange portion is sandwiched between the tip portion of the annular flange portion and the bottom surface of the annular groove portion in the axial direction of the cylindrical portion, so that the cup is assembled to the holder. A gas generator in which the entire portion included in the first surface and which overlaps with the inclined surface when viewed along the axial direction of the cylindrical portion has a planar shape perpendicular to the axial direction of the cylindrical portion.

2. The gas generator according to claim 1, wherein the corner located between the first surface and the inner circumferential surface of the cylindrical portion is formed by a curved surface that is smoothly continuous with any of these adjacent surfaces.

3. The gas generator according to claim 1, wherein the cup is made of aluminum.

4. A lock release device comprising a gas generator according to any one of claims 1 to 3, wherein the lock on a locked portion is released when the gas generator is operated, The aforementioned lock release device further comprises a housing with a through hole in the wall, A locking pin for locking the locked portion is erected in the closing portion, facing away from the holder side. The gas generator is housed inside the container such that the locking pin is inserted through the through hole, allowing the locking portion to be locked by the locking pin located outside the container. A locking release device wherein, upon operation of the gas generator, the pressure in the space outside the gas generator and inside the containment increases, causing the gas generator to move away from the wall portion of the through-hole, thereby pulling the locking pin into the containment and releasing the lock on the locked portion.

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