Gas generator

Abstract

The present application relates to a gas generator. An igniter holding structure is provided with: an igniter having an ignition portion including an ignition agent and a conductive pin extending from the ignition portion; a first resin portion made of resin, which is provided between the igniter and a mounting portion to hold the igniter in a manner that the ignition portion and the tip end of the conductive pin are located on opposite sides with a through hole therebetween and the conductive pin is surrounded by a peripheral wall portion; and a second resin portion made of resin, which is provided to the peripheral wall portion to form a connector insertion portion that is a space into which a connector connected to the conductive pin can be inserted on the inner side of the peripheral wall portion, the second resin portion being provided on the inner side of the peripheral wall portion spaced apart from the first resin portion in a manner that a metal exposed surface exposed to the connector insertion portion is formed on the peripheral wall portion.

Description

[0001] This application is a divisional application of Chinese invention patent application (PCT application number PCT / JP2020 / 030025) filed on August 5, 2020, with application number 202080060475.3 and invention title "Igniter Holding Structure". Technical Field

[0002] This invention relates to an igniter holding structure for a gas generator. Background Technology

[0003] Igniters are widely known as starting devices for gas generators in airbags, seat belt retractors, etc., and they primarily operate by means of ignition current. As for structures for mounting igniters to gas generators, structures are known that use resin to mount the igniter to a cylindrical component housed in a casing.

[0004] Relatedly, in the gas generator shown in Patent Document 1, a cylindrical mounting portion for mounting an igniter is formed at the center of the base plate of the housing. The igniter is fixed to one end of the mounting portion by resin provided between the igniter and the mounting portion. The resin also forms a space on the other end of the mounting portion for inserting a connector for supplying current to the igniter.

[0005] In the gas generator shown in Patent Document 2, a conductive member is further embedded in the resin, exposing it to the insertion space of the connector so that the grounding terminal of the connector contacts the conductive member. This suppresses the accumulation of static electricity in the metal casing, preventing malfunction of the igniter. Furthermore, in the gas generator of Patent Document 2, grooves for resin material flow are formed in the conductive member during injection molding, thereby connecting the resin used to hold the igniter with the resin used to form the insertion space of the connector inside the mounting portion, thus forming these resins integrally.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: US Patent No. 7,540,241

[0009] Patent Document 2: Japanese Patent Application Publication No. 2013-227010 Summary of the Invention

[0010] The problem the invention aims to solve

[0011] As in existing technologies, in structures where the igniter is mounted via resin, even if sufficient insertion space for the connector is ensured, if the resin used to hold the igniter and the resin used to form the insertion space for the connector are bonded inside the mounting portion, the bonded portion tends to form a thin wall along the inner surface of the mounting portion. This can reduce the strength of this portion, making the resin susceptible to damage. Furthermore, depending on the type of resin, it may have moisture-absorbing properties; in this case, a thin resin tends to absorb moisture more easily. Therefore, if a thin-walled portion is formed in the resin, moisture may pass through this thin-walled portion and easily penetrate the interior of the gas generator. If moisture penetrates the interior of the gas generator, the following problems arise: it becomes difficult to maintain the gas generating agent contained inside the gas generator in a dry state, and the performance of the gas generator becomes unstable.

[0012] The technology disclosed herein was made in view of the above-mentioned problems, and its object is to provide a technology that can suppress resin damage and moisture intrusion in an igniter holding structure for a gas generator that mounts an igniter to a metal mounting part with a resin barrier.

[0013] This invention relates to the following:

[0014] Item 1. An igniter holding structure, which is an igniter holding structure for a gas generator used to mount an igniter to a metal mounting part, wherein,

[0015] The mounting portion has a through hole for the igniter to pass through and a peripheral wall portion including the inner surface of the through hole.

[0016] The igniter retaining structure includes:

[0017] An igniter having an ignition part including an ignition powder and a conductive pin extending from the ignition part;

[0018] A first resin portion, disposed between the igniter and the mounting portion, holds the igniter in such a manner that the igniter and the tip of the conductive pin are located on opposite sides of each other across the through hole, and the conductive pin is surrounded by the peripheral wall portion; and

[0019] A second resin portion is provided on the peripheral wall portion, and a connector insertion portion is formed on the inner side of the peripheral wall portion to serve as a space for inserting a connector that can be connected to the conductive pin.

[0020] The second resin portion is disposed at a distance from the first resin portion on the inner side of the peripheral wall portion such that a metal exposed surface that protrudes to the connector insertion portion is formed on the peripheral wall portion.

[0021] Item 2. The igniter retaining structure according to Item 1, wherein,

[0022] The exposed surface is formed as a portion of the peripheral wall portion that is exposed to the connector insertion portion because the second resin portion is spaced apart from the first resin portion on the inner side of the peripheral wall portion.

[0023] Item 3. The igniter retaining structure according to Item 1 or 2, wherein,

[0024] In the mounting portion, in addition to the through hole, a connecting hole is also formed, extending from the first resin portion side across the peripheral wall portion to the second resin portion side.

[0025] The first resin portion and the second resin portion are connected inside the connecting hole.

[0026] Item 4. The igniter retaining structure according to any one of items 1 to 3, wherein,

[0027] The peripheral wall portion has: an inner peripheral wall portion having the exposed surface; and a near-front peripheral wall portion formed in the insertion direction of the connector relative to the connector insertion portion, extending further outward than the inner peripheral wall portion and beyond the exposed surface of the peripheral wall portion.

[0028] The second resin portion is provided on the near-front peripheral wall portion in a manner that does not obstruct the insertion of the connector into the connector insertion portion.

[0029] Item 5. The igniter retaining structure according to Item 4, wherein,

[0030] The connector guide surface, which is the surface of the second resin portion opposite to the connector, is formed to be flush with the exposed surface.

[0031] Item 6. The igniter retaining structure according to Item 4, wherein,

[0032] A stepped portion is formed between the exposed surface and the connector guide surface, such that the connector guide surface, which is the surface of the second resin portion opposite to the connector, is located inside the peripheral wall portion compared to the exposed surface.

[0033] The stepped portion is configured such that, when the connector is inserted into the connector insertion portion, the connector is restricted from being pulled out of the connector insertion portion by engaging the protrusion protruding from the connector with the stepped portion.

[0034] Item 7. The igniter retaining structure according to any one of items 1 to 6, wherein,

[0035] The exposed surface is formed such that it can contact the grounding terminal when the connector with the grounding terminal is inserted into the connector insertion portion.

[0036] Item 8. The igniter retaining structure according to any one of items 1 to 7, wherein,

[0037] The first resin portion includes:

[0038] A retaining portion holds the igniter in such a manner that the ignition portion and the tip of the conductive pin are located on opposite sides across the through hole, and the conductive pin is surrounded by the peripheral wall portion; and

[0039] The cylindrical portion is formed with one end connected to the retaining portion and the other end closed. The cylindrical portion internally accommodates a portion of the ignition portion, and a combustion chamber is formed between the cylindrical portion and the ignition portion to accommodate the gaseous propellant that burns through the operation of the ignition portion.

[0040] The retaining part and the cylindrical part are integrally formed.

[0041] Technical solution

[0042] To achieve the above objective, in the ignition retaining structure disclosed herein, the resin used to retain the ignition is spaced apart from the resin used to form the insertion space of the connector on the inner side of the mounting portion, thereby preventing the resin from becoming a thin wall on the inner side of the mounting portion.

[0043] More specifically, the disclosed technology is an igniter holding structure for a gas generator used to mount an igniter to a metal mounting portion. The mounting portion has a through hole through which the igniter passes and a peripheral wall portion including the inner surface of the through hole. The igniter holding structure comprises: an igniter having an ignition portion including an ignition propellant and a conductive pin extending from the ignition portion; a first resin portion disposed between the igniter and the mounting portion, holding the igniter such that the ignition portion and the top of the conductive pin are on opposite sides across the through hole and the conductive pin is surrounded by the peripheral wall portion; and a second resin portion disposed on the peripheral wall portion, forming a connector insertion portion on the inner side of the peripheral wall portion as a space for inserting a connector connected to the conductive pin. The second resin portion is spaced apart from the first resin portion on the inner side of the peripheral wall portion such that a metal exposed surface to the connector insertion portion is formed on the peripheral wall portion.

[0044] According to the igniter retaining structure disclosed herein, the resin used to retain the igniter is prevented from bonding with the resin used to form the insertion space of the connector on the inner side of the peripheral wall portion, that is, bonding is prevented on the inner side of the mounting portion. This prevents the resin from forming a thin wall on the inner side of the mounting portion. As a result, the strength of the resin on the inner side of the mounting portion is ensured, and resin damage is suppressed. Furthermore, the intrusion of moisture into the interior of the gas generator caused by the resin forming a thin wall can be appropriately suppressed. More specifically, the transmission of moisture in the thin-walled portion of the resin can be appropriately suppressed, thereby preventing moisture from intruding around the igniter, that is, intruding into the combustion chamber, which is the space containing the gas generating agent that is burned by the igniter. As a result, the dry state of the gas generating agent in the combustion chamber can be appropriately maintained, stabilizing the performance of the gas generator.

[0045] It should be noted that the igniter retaining structure disclosed herein can be applied to gas generators for airbags and gas generators for seat belt retractors. Furthermore, the applied gas generator can be a single-stage gas generator with only one igniter, or a dual-stage gas generator with two igniters. Additionally, the mounting portion can be formed as part of the housing of the gas generator, or it can be formed as a separate collar. Moreover, the igniter retaining structure is not limited to being embedded in a gas generator; it can also be in the form of an igniter assembly that combines the igniter retaining structure, including the igniter, the first resin part, and the second resin part, with the collar serving as the mounting portion.

[0046] Alternatively, in the igniter retaining structure described above, the exposed surface can be formed as a portion of the peripheral wall portion that is spaced apart from the first resin portion by the second resin portion on the inner side of the peripheral wall portion and exposed to the connector insertion portion. This eliminates the need to separately provide the part for forming the exposed surface from the peripheral wall portion, thus suppressing the increase in the number of parts and assembly time.

[0047] Alternatively, in the above-described igniter retaining structure, in addition to the through hole formed in the mounting portion, a connecting hole is also formed from the first resin portion side through the second resin portion side, separated by the peripheral wall portion, and the first resin portion and the second resin portion are connected inside the connecting hole. Thus, the resin connecting the first and second resin portions inside the connecting hole engages with the inner surface of the connecting hole, thereby suppressing rotation of the first and second resin portions relative to the mounting portion. Furthermore, from the viewpoint of manufacturing the igniter retaining structure, when the first and second resin portions are molded by injection molding, resin material flowing into the molding die from either the first or second resin portion side can flow through the connecting hole to the other side. Therefore, the first and second resin portions can be molded simultaneously in a single injection molding process, thus reducing manufacturing time. Moreover, only one gate is needed—either a gate for resin material flowing from the first resin portion side or a gate for resin material flowing from the second resin portion side—thus simplifying manufacturing equipment.

[0048] Alternatively, in the aforementioned igniter retaining structure, the peripheral wall portion may have: an inner peripheral wall portion having the exposed surface; and a near-front peripheral wall portion formed in the insertion direction of the connector relative to the connector insertion portion, extending outward from the exposed surface of the peripheral wall portion and closer to the front than the inner peripheral wall portion. The second resin portion is provided in the near-front peripheral wall portion in a manner that does not obstruct the insertion of the connector into the connector insertion portion. Thus, by providing the second resin portion in the near-front peripheral wall portion that extends outward from the exposed surface of the peripheral wall portion, that is, by providing the second resin portion in a wider space, the size of the connector insertion portion can be sufficiently ensured, and the second resin portion can be formed as a thicker wall. As a result, the strength of the second resin portion can be improved.

[0049] Furthermore, in the igniter retaining structure, the connector guide surface, which is the surface of the second resin section opposite to the connector, can be formed flush with the exposed surface. This allows the connector to be guided smoothly into the connector insertion section without being obstructed by the exposed surface or stopping at a position further inward than the connector guide surface (exposed surface side).

[0050] Alternatively, in the igniter retaining structure, a step can be formed between the exposed surface and the connector guide surface, such that the connector guide surface is located inside the peripheral wall portion of the exposed surface. This step can be configured such that, when the connector is inserted into the connector insertion portion, a protrusion protruding from the connector engages with the step to restrict the connector from being pulled out of the connector insertion portion. Thus, the step formed between the exposed surface and the connector guide surface can be used to prevent connector disengagement.

[0051] Alternatively, in the aforementioned igniter holding structure, the exposed surface may be formed such that it can contact the grounding terminal when the connector with the grounding terminal is inserted into the connector insertion portion. Here, the grounding terminal refers to a terminal electrically connected to an external grounding circuit. According to such an igniter holding structure, the exposed metal surface contacts the grounding terminal, thereby electrically connecting the mounting portion with the exposed surface to the grounding terminal. Consequently, if the gas generator housing is charged, the charge flows from the mounting portion through the grounding terminal to the grounding circuit. As a result, the charge in the gas generator is safely discharged, preventing malfunction of the igniter caused by static electricity. For example, if the mounting portion is formed in part of the housing, the charge accumulated in the housing is safely discharged. However, the igniter holding structure of this disclosure may not correspond to a connector with a grounding terminal, and may also connect to a connector without a grounding terminal. That is, the exposed surface may not be formed to contact the grounding terminal of the connector.

[0052] Alternatively, in the above-described igniter holding structure, the first resin portion may include: a holding portion that holds the igniter so that the igniter and the top of the conductive pin are located on opposite sides across the through hole, and the conductive pin is surrounded by the peripheral wall portion; and a cylindrical portion formed as a cylinder with one end connected to the holding portion and the other end closed, the cylindrical portion accommodating a portion of the igniter inside, and forming a combustion chamber between the cylindrical portion and the igniter to accommodate the gas generator that burns through the operation of the igniter, the holding portion and the cylindrical portion may be integrally formed. Thus, by forming the combustion chamber from a portion of the first resin portion (the cylindrical portion), compared to forming the combustion chamber from other components, the number of parts and assembly time can be reduced. Furthermore, by forming the combustion chamber inside the first resin portion, moisture can be prevented from penetrating the combustion chamber through the space between the mounting portion and the first resin portion.

[0053] Invention Effects

[0054] According to the technology disclosed herein, in the igniter holding structure for a gas generator, damage to the resin and intrusion of moisture can be suppressed. Attached Figure Description

[0055] Figure 1 This is an axial cross-sectional view of a gas generator having the igniter holding structure of Embodiment 1.

[0056] Figure 2 This is an axial cross-sectional view showing the vicinity of the igniter holding structure in the gas generator of Embodiment 1.

[0057] Figure 3This is an axial cross-sectional view showing the state in which the gas generator of Embodiment 1 is connected to a connector.

[0058] Figure 4 This is a diagram showing the manufacturing process of the igniter retaining structure according to Embodiment 1.

[0059] Figure 5 This is an axial cross-sectional view showing the vicinity of the igniter holding structure in the gas generator of Modified Example 1 of Embodiment 1.

[0060] Figure 6 This is a diagram showing the manufacturing process of the igniter retaining structure of a variation of Embodiment 1.

[0061] Figure 7 This is an axial cross-sectional view near the igniter holding structure in the gas generator of Modification 2 of Embodiment 1.

[0062] Figure 8 This is an axial cross-sectional view showing the state in which the gas generator of Modified Example 2 of Embodiment 1 is connected to a connector.

[0063] Figure 9 This is an axial cross-sectional view near the igniter retaining structure in the gas generator of Variation 3 of Embodiment 1.

[0064] Figure 10 This is an axial cross-sectional view of a gas generator having the igniter holding structure of Embodiment 2.

[0065] Figure 11 This is an axial cross-sectional view of a gas generator having an igniter holding structure according to a modified embodiment of embodiment 2. Detailed Implementation

[0066] Hereinafter, a gas generator according to an embodiment of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the various components and combinations thereof in each embodiment are merely examples, and appropriate additions, omissions, substitutions, and other modifications to the components can be made without departing from the spirit of the invention. The present invention is not limited to the embodiments, but only to the claims.

[0067] <Implementation Method 1>

[0068] As Embodiment 1, the application of the igniter holding structure of this disclosure to a gas generator for an airbag will be described.

[0069] [Overall Composition]

[0070] Figure 1This is an axial cross-sectional view of a gas generator having the igniter holding structure of Embodiment 1. The gas generator 100 is configured as a so-called single-stage gas generator having an igniter indicated by reference numeral 4. Specifically, as... Figure 1 As shown, the gas generator 100 includes a housing 1, an igniter 4, a first resin section 5, a second resin section 6, and a filter 7. The gas generator 100 is configured such that by activating the igniter 4, the gas generating agent 110 contained in the housing 1 is combusted, and the combustion gas, as a combustion product, is discharged from the gas discharge port 13 formed in the housing 1, thereby causing the gasbag (not shown) to inflate and expand. Figure 1 As shown, the igniter 4 is mounted on the housing 1 while being held by the first resin part 5. Furthermore, the second resin part 6 is formed as a connector 200 (see reference 1) into which power (ignition current) can be supplied to the igniter 4. Figure 3 The connector insertion part A1 is located in the space of the gas generator 100. In this specification, the structure for mounting the igniter 4 to the housing 1, including the igniter 4, the first resin part 5, and the second resin part 6, is referred to as the igniter holding structure 10. Hereinafter, each component of the gas generator 100 will be described in detail.

[0071] [shell]

[0072] like Figure 1 As shown, the outer casing 1 is formed into a short-sized cylindrical shape with both ends closed axially by joining an upper casing 2 and a lower casing 3, which are respectively formed as bottomed cylindrical metal parts, with their open ends facing each other. However, the configuration of the upper casing 2 and the lower casing 3 is not limited to this, and known configurations can be used appropriately. Here, the direction along the axial direction of the outer casing 1 is defined as the vertical direction of the gas generator 100, and the upper casing 2 side (i.e., Figure 1 The upper side of the lower housing 3 (i.e., the upper side of the lower housing 3) is set as the upper side of the gas generator 100, and the lower housing 3 (i.e., the upper side of the lower housing 3) is set as the upper side of the gas generator 100. Figure 1 The lower side of the gas generator 100 is designated as the lower side of the gas generator 100.

[0073] The upper housing 2 has a cylindrical upper cylindrical portion 21 and a top plate portion 22 that closes the upper end of the upper cylindrical portion 21. The top plate portion 22 has a generally circular shape when viewed from above. The upper cylindrical portion 21 extends substantially vertically from the periphery of the top plate portion 22, thereby forming a cylindrical peripheral wall. The top plate portion 22 is connected to the upper end of the upper cylindrical portion 21, and an opening is formed at the lower end of the upper cylindrical portion 21. Furthermore, a joint portion 23 extending radially outward is connected to the lower end of the upper cylindrical portion 21. The lower housing 3 has a cylindrical lower cylindrical portion 31 and a bottom plate portion 32 that closes the lower end of the lower cylindrical portion 31. The bottom plate portion 32, like the top plate portion 22 of the upper housing 2, has a generally circular shape when viewed from above. A joint portion 33 extending radially outward is connected to the upper end of the lower cylindrical portion 31. The upper housing 2 and the lower housing 3 are joined together by overlapping the joint 23 and laser welding or the like, thereby forming the outer shell 1. Furthermore, a plurality of gas vent holes 13 communicating with the inside and outside of the outer shell 1 are formed circumferentially in the upper cylindrical portion 21 of the upper housing 2. The gas vent holes 13 are sealed by a sealing strip (not shown).

[0074] Here, as Figure 1 As shown, a mounting portion 34 for mounting the igniter 4 is provided in the lower housing 3 of the outer casing 1. In this embodiment, the mounting portion 34 is integrally formed with the base plate portion 32. That is, the mounting portion 34 is formed from a part of the outer casing 1. Therefore, the mounting portion 34 is made of metal. Figure 2 This is an axial cross-sectional view showing the vicinity of the igniter holding structure 10 in the gas generator 100 of Embodiment 1. (See attached image.) Figure 2 As shown, the mounting portion 34 is formed in a generally cylindrical shape, protruding upward from the base plate portion 32 through a portion of the lower housing 3. A through hole h1 is formed at the upper end of the mounting portion 34 for the conductive pin 42 of the igniter 4 to pass through. A peripheral wall portion 35, including the inner surface of the through hole h1, extends from the periphery of the through hole h1 and connects to the base plate portion 32. More specifically, the peripheral wall portion 35 has: a hole forming portion 350, including the inner surface of the through hole h1 and extending radially outward from the through hole h1; a cylindrical inner peripheral wall portion 351, extending downward from the outer peripheral end of the hole forming portion 350; a connecting portion 352, extending radially outward from the lower end of the inner peripheral wall portion 351; and a cylindrical near-front peripheral wall portion 353, extending downward from the outer peripheral end of the connecting portion 352 and connecting to the base plate portion 32. Figure 2As shown, the near-front peripheral wall portion 353 is formed with a larger inner diameter compared to the inner peripheral wall portion 351. The connecting portion 352 connects the inner peripheral wall portion 351 and the near-front peripheral wall portion 353, and an annular step is formed between the inner peripheral wall portion 351 and the near-front peripheral wall portion 353. It should be noted that, in the following description, the inner side of the peripheral wall portion 35 and the inner side of the mounting portion 34 refer to the inner side of the area surrounded by the peripheral wall portion 35, including the inner side of the through hole h1. Furthermore, the inner surface of the peripheral wall portion 35 refers to the inner-facing wall surface of the peripheral wall portion 35, including the inner surface of the through hole h1. Figure 2 As shown, the inner surface of the peripheral wall portion 35 is connected to the lower surface of the base plate portion 32, thereby creating an opening in the lower space of the outer casing 1 at the lower end of the peripheral wall portion 35. It should be noted that in this example, the connecting portion 352 of the peripheral wall portion 35 forms a surface extending in the horizontal direction; however, the connecting portion 352 could also form an annular inclined surface connecting the inner peripheral wall portion 351 and the near-front peripheral wall portion 353. Furthermore, the peripheral wall portion 35 could also have a peripheral wall forming an annular inclined surface from the lower end of the inner peripheral wall portion 351 to the base plate portion 32, instead of the connecting portion 352 and the near-front peripheral wall portion 353.

[0075] [Filter]

[0076] Filter 7 is formed in a cylindrical shape, such as Figure 1 As shown, the filter 7 is positioned between the igniter 4 and the gas discharge port 13, with its upper end supported by the top plate 22 of the upper housing 2 and its lower end supported by the bottom plate 32 of the lower housing 3. A combustion chamber 11 is formed between the igniter 4 and the filter 7. The combustion chamber 11 contains the gas generating agent 110 that is burned by the operation of the igniter 4. Furthermore, an annular gap 12 is formed between the filter 7 and the housing 1 (upper cylinder 21 and lower cylinder 31). The filter 7 is configured such that combustion gases can pass through it, and the combustion gases generated in the combustion chamber 11 are cooled by passing through the filter 7. At this time, the filter 7 filters the combustion gases by capturing combustion residues.

[0077] [Gas Generator]

[0078] As the gas generator 110 contained in the combustion chamber 11, a gas generator with a known composition can be used. When using a gas generator with a lower combustion temperature as the gas generator 110, for example, a known gas generator composed of guanidine nitrate (41% by weight), basic copper nitrate (49% by weight), and binders or additives can be used. Furthermore, the gas generator 110 can be in various shapes, such as granules, pellets, cylinders, or discs.

[0079] [Igniter retaining structure]

[0080] like Figure 2As shown, the igniter holding structure 10 includes: an igniter 4 for igniting the gas generator 110; a first resin part 5 for holding the igniter 4; and a second resin part 6 for forming a connector insertion part A1 that serves as a space for inserting into the connector 200. Figure 3 This is an axial cross-sectional view showing the state in which the gas generator 100 in Embodiment 1 is connected to the connector 200. The connector 200 is connected to: a power supply wire 300, connected to an external power source (not shown) for supplying power to the gas generator 100; and a grounding wire 400, connected to a grounding circuit (not shown) for discharging the charge accumulated in the gas generator 100. The connector 200 is inserted into the connector insertion portion A1 from below the gas generator 100. That is, in this example, the insertion direction of the connector 200 into the connector insertion portion A1 is... Figure 3 The upward direction is consistent with that shown.

[0081] like Figure 2 and Figure 3 As shown, in the igniter holding structure 10, the first resin portion 5 and the second resin portion 6 are separated by the peripheral wall portion 35. By separating the first resin portion 5 and the second resin portion 6 on the inner side of the peripheral wall portion 35, the igniter holding structure 10 of this embodiment ensures the strength of the resin in the igniter holding structure 10 and suppresses the intrusion of moisture into the interior of the gas generator 100. Hereinafter, refer to... Figure 2 and Figure 3 The components of the igniter holding structure 10 will be explained.

[0082] [Igniter]

[0083] like Figure 2 and Figure 3As shown, the igniter 4 has an ignition part 41 including an ignition powder 120 for igniting and burning the gas generator 110, and a pair of conductive pins 42, 42 extending downward from the ignition part 41. A connector 200 is connected to the pair of conductive pins 42, 42. The igniter 4 operates using electricity supplied from an external power source to each conductive pin 42 via the connector 200, thereby igniting the ignition powder 120 in the ignition part 41 and igniting and burning the gas generator 110 contained in the combustion chamber 11. The ignition part 41 has: a bottomed cylindrical cup body 411, closed at the upper end and open at the lower end; and a cylindrical metal sealing head 412, configured to close the opening formed at the lower end of the cup body 411. The metal sealing head 412 is welded to the inner wall of the cup body 411 on its outer peripheral surface. The ignition chamber 413, which is the space defined by the cup body 411 and the metal sealing head 412, contains the ignition powder 120 for igniting the gas generator 110. A through hole is formed in the center of the metal sealing head 412. One of the pair of conductive pins 42, 42 is inserted into the through hole of the metal sealing head 412 and is engaged with the metal sealing head 412 through an insulator 43. In addition, a bridge wire 44, which serves as a resistor connecting one of the conductive pins 42 to the metal sealing head 412, is wired at the bottom of the ignition chamber 413. The other of the pair of conductive pins 42, 42 is engaged with the lower surface of the metal sealing head 412. Hereinafter, each of the pair of conductive pins 42, 42 will be referred to simply as conductive pin 42 without distinction.

[0084] [First Resin Section]

[0085] The first resin part 5, formed of resin material, is disposed between the igniter 4 and the mounting part 34, thereby fixing the igniter 4 relative to the mounting part 34. At this time, as... Figure 2 and Figure 3 As shown, the first resin part 5 holds the igniter 4 with the ignition part 41 and the top end 421 of the conductive pin 42 on opposite sides across the through hole h1 of the mounting part 34, and the conductive pin 42 is surrounded by the peripheral wall part 35 of the mounting part 34. In other words, the igniter 4 is held by the first resin part 5 with the ignition part 41 on the upper side and the top end 421 of the conductive pin 42 on the lower side across the through hole h1.

[0086] The first resin portion 5 covers the outer side of the peripheral wall portion 35, the inner side of the hole forming portion 350, the inner side of the peripheral wall portion 351, and the connecting portion 352, and covers the inner side of the hole forming portion 350 (including the inner surface of the through hole h1) and a portion of the inner side of the peripheral wall portion 351. Furthermore, relative to the igniter 4, the first resin portion 5 covers the lower part of the ignition portion 41 and the upper part of the conductive pin 42, including the upper end of the cup body 411, which protrudes into the combustion chamber 11, and the lower part of the conductive pin 42, including the top end 421, protrudes into the connector insertion portion A1.

[0087] Here, as Figure 3 As shown, the connector 200 has a pin insertion hole 201 for inserting a conductive pin 42 when the connector 200 is inserted into the connector insertion portion A1. A conductive terminal 202, which is connected to the power supply wire 300, is provided inside the pin insertion hole 201. Figure 3 As shown, when connector 200 is inserted into connector insertion part A1, conductive pin 42 inserted into pin insertion hole 201 contacts conductive terminal 202. With conductive pin 42 in contact with conductive terminal 202, connector 200 is connected to igniter 4, enabling power supply to igniter 4.

[0088] The first resin portion 5 is formed by injection molding of resin material. As the resin material forming the first resin portion 5, thermoplastic resins commonly used in injection molding can be used, such as polybutylene terephthalate resin, polyethylene terephthalate resin, polyamide resin, vulcanized polypropylene resin, polypropylene oxide resin, etc. It should be noted that the range of formulations for the first resin portion 5 is not limited to... Figure 2 , Figure 3 For example, on the outer side of the peripheral wall portion 35, the first resin portion may only cover the hole forming portion 350, exposing the outer peripheral surface of the inner peripheral wall portion 351 and the outer peripheral surface of the connecting portion 352. Alternatively, the first resin portion 5 may be configured to only cover the hole forming portion 350 on the inner side of the peripheral wall portion 35.

[0089] [Second Resin Section]

[0090] The second resin part 6 is formed of resin material, such as Figure 2 and Figure 3 As shown, a connector insertion portion A1, serving as a space for inserting the connector 200, is formed on the inner side of the peripheral wall portion 35. The second resin portion 6 is formed in a cylindrical or annular shape on the inner side of the peripheral wall portion 35, covering the connecting portion 352 and the near-front peripheral wall portion 353, and the connector insertion portion A1 is formed on the inner surface of the second resin portion 6. Here, as... Figure 3As shown, the connector 200 has a protrusion 203 that protrudes outward from the peripheral wall portion 35 when the connector 200 is inserted into the connector insertion portion A1. Correspondingly, on the inner surface of the second resin portion 6, a portion of the second resin portion 6 is recessed outward, thereby forming an engaging recess 61 that engages with the protrusion 203 of the connector 200 inserted into the connector insertion portion A1. During the insertion of the connector 200 into the connector insertion portion A1, the connector 200 is inserted while the protrusion 203 elastically deforms, and when the protrusion 203 reaches the engaging recess 61, the protrusion returns to its original position by opening outward again. Therefore, when the insertion of the connector 200 is completed, the protrusion 203 engages with the engaging recess 61. This prevents the connector 200 from being unintentionally pulled out of the connector insertion portion A1.

[0091] The second resin portion 6 is formed by injection molding of resin material. The resin material used to form the second resin portion 6 is the same thermoplastic resin commonly used in injection molding as the first resin portion 5. It should be noted that the first resin portion 5 and the second resin portion 6 can be formed from the same resin material or from different resin materials.

[0092] Here, as Figure 2 and Figure 3 As shown, the second resin portion 6 is spaced apart from the first resin portion 5 on the inner side of the peripheral wall portion 35 such that a portion of the inner surface of the peripheral wall portion 35 is exposed to the connector insertion portion A1. More specifically, the second resin portion 6 is spaced apart from the first resin portion 5 on the inner side of the peripheral wall portion 35, thereby exposing a portion of the inner peripheral wall portion 351 (the portion not covered by the first resin portion 5) to the connector insertion portion A1. This portion of the inner surface of the peripheral wall portion 35 that is exposed to the connector insertion portion A1 is called the exposed surface S1. The peripheral wall portion 35 is made of metal, therefore, the exposed surface S1 is a metal surface. This exposed surface S1 is formed in a ring shape. That is, the exposed surface S1 is continuously formed in the inner circumference of the peripheral wall portion 35 in a manner that covers the entire circumference, thereby separating the first resin portion 5 and the second resin portion 6 on the inner side of the peripheral wall portion 35. Furthermore, the exposed surface S1 is exposed to the connector insertion portion A1, thereby defining the connector insertion portion A1 together with the inner surface of the second resin portion 6.

[0093] The first resin portion 5 and the second resin portion 6 are spaced vertically apart on the inner side of the peripheral wall portion 35 such that an exposed surface S1 is formed therebetween. The second resin portion 6 is located below the exposed surface S1, that is, near the front side in the insertion direction. At this time, as Figure 3 As shown, the second resin part 6 is provided in the near-front peripheral wall part 353, which extends outward from the exposed surface S1 toward the peripheral wall part 35, in a manner that does not obstruct the insertion of the connector 200 into the connector insertion part A1.

[0094] Here, the surface on the inner surface of the second resin portion 6 that faces the connector 200 inserted into the connector insertion portion A1 is referred to as the connector guide surface S2. The connector guide surface S2 is formed adjacent to the exposed surface S1 below the exposed surface S1 (i.e., near the front side in the insertion direction). The connector guide surface S2 serves to guide the connector 200 inwards from the connector guide surface S2 when the connector 200 is inserted into the connector insertion portion A1. Figure 2 and Figure 3 As shown, the connector inlet surface S2 is formed to be flush with the exposed surface S1.

[0095] Here, the connector 200 has a grounding terminal 204 that protrudes into the connector insertion portion A1 when the connector 200 is inserted into the connector insertion portion A1. The grounding terminal 204 is electrically connected to the grounding circuit via a grounding wire 400. At this time, as Figure 3 As shown, the exposed surface S1 is formed such that the grounding terminal 204 of the connector 200, which is inserted into the connector insertion portion A1, contacts the exposed surface S1. The exposed surface S1 is part of the housing 1; therefore, the exposed surface S1 contacts the grounding terminal 204, thereby electrically connecting the housing 1 to the grounding terminal 204. Consequently, when a charge accumulates in the housing 1, the charge flows to the grounding circuit via the grounding terminal 204 and the grounding wire 400.

[0096] [Action]

[0097] Next, the operation of the gas generator 100 will be explained. When the gas generator 100 is assembled in the automobile, as... Figure 3 As shown, the connector 200, inserted into the connector insertion part A1, connects to the igniter 4, enabling power supply to the igniter 4. In this state, when a sensor (not shown) mounted on the vehicle detects a collision, power from an external power source is supplied to the conductive pin 42 via the conductive terminal 202 of the connector 200. Current flows into the bridge wire 44, and the ignition propellant 120 in the ignition chamber 413 burns due to the Joule heat generated in the bridge wire 44. Simultaneously, due to the increased pressure within the ignition chamber 413, the cup 411 ruptures, and the high-temperature flame, a combustion product of the ignition propellant 120, is expelled upwards. This ignites the gas generator 110 in the combustion chamber 11. The combustion gases of the gas generator 110 are cooled and filtered by the filter 7, pass through the gap 12, and are discharged from the gas outlet 13 to the outside of the outer casing 1, flowing into the airbag (not shown). The airbag then inflates and deploys, forming a buffer between the occupant and a rigid structure, protecting the occupant from impact.

[0098] [Manufacturing method for igniter retaining structure]

[0099] Next, the manufacturing method of the igniter holding structure 10 will be described. In the manufacturing method of the igniter holding structure 10 of this embodiment, the first resin part 5 and the second resin part 6 are formed by injection molding using a molding die. In this example, the first resin part 5 and the second resin part 6 are formed from the same resin material. Figure 4 This diagram illustrates the manufacturing process of the igniter holding structure 10 according to Embodiment 1. First, in the preparation step S101, an igniter 4, a lower housing 3 including a mounting portion 34 (to which the igniter 4 is mounted), and resin material serving as the raw material for the first resin portion 5 and the second resin portion 6 are prepared. The igniter 4 and the lower housing 3 are then placed in a molding die. Next, in the first resin portion molding step S102, the resin material (hereinafter, the first resin material) serving as the raw material for the first resin portion 5 is melted, injected into the mold, and then cured, thereby injection molding the first resin portion 5. In step S102, the molten first resin material flows into the mold through a gate for first resin material and cures. Thus, the igniter 4 is fixed to the mounting portion 34 while being held by the first resin portion 5. Next, in the second resin portion molding step S103, the resin material (hereinafter, the second resin material) serving as the raw material for the second resin portion 6 is melted, injected into the mold, and then cured, thereby injection molding the second resin portion 6. Figure 2 As shown, in the igniter holding structure 10, the first resin portion 5 and the second resin portion 6 are separated by a peripheral wall portion 35. Therefore, in step S103, the molten second resin material is allowed to flow in from a gate for the second resin material that is different from the gate for the first resin material and then solidify. This forms a connector insertion portion A1 on the inner side of the peripheral wall portion 35. At this time, the second resin portion 6 is formed on the inner side of the peripheral wall portion 35 in a manner that separates it from the first resin portion 5, thereby forming an exposed surface S1 on the inner side of the peripheral wall portion 35, where a portion of the peripheral wall portion 35 protrudes into the connector insertion portion A1. The igniter holding structure 10 is manufactured as described above. It should be noted that for the molding of the first resin portion 5 achieved in step S102 and the molding of the second resin portion 6 achieved in step S103, step S103 can be performed first, or steps S102 and S103 can be performed simultaneously.

[0100] [Function / Effect]

[0101] Furthermore, in the technologies described in Patent Documents 1 and 2, the resin used to hold the igniter and the resin used to form the insertion space of the connector are connected inside the cylindrical mounting portion of the housing, forming them as a single unit. However, if it is desired to ensure the insertion space of the connector within the limited space inside the mounting portion, the size of the space in which the resin can be installed is limited. Therefore, as in the aforementioned technologies, if it is desired to connect the resin used to hold the igniter and the resin used to form the insertion space of the connector inside the mounting portion, the portion connecting the resins tends to be thin along the inner surface of the mounting portion. In other words, the resin may form a thin wall inside the mounting portion. If the resin forms a thin wall, the strength of the resin may be reduced, and the resin may be easily damaged. In addition, depending on the type of resin material, it may have the property of absorbing moisture; in this case, if it is thin-walled, it tends to easily absorb moisture. Therefore, in the aforementioned technologies, moisture may be transmitted through the thin-walled portion of the resin and enter the combustion chamber, thereby affecting the ignition and combustion performance of the gas generator contained in the combustion chamber.

[0102] In contrast, in the igniter holding structure 10 of this embodiment, the second resin portion 6 is spaced apart from the first resin portion 5 on the inner side of the peripheral wall portion 35, with the exposed metal surface S1 exposed to the connector insertion portion A1 formed on the peripheral wall portion 35 of the mounting portion 34. That is, the resin used to hold the igniter and the resin used to form the insertion space of the connector are prevented from being connected on the inner side of the peripheral wall portion 35 (i.e., the inner side of the mounting portion 34). This prevents the resin from forming a thin wall on the inner side of the mounting portion 34. As a result, the strength of the resin on the inner side of the mounting portion 34 is ensured, and resin damage is suppressed. Furthermore, the intrusion of moisture into the combustion chamber 11 caused by the resin forming a thin wall can be appropriately suppressed. As a result, the dry state of the gas generator 110 in the combustion chamber 11 can be appropriately maintained, stabilizing the performance of the gas generator 100.

[0103] Furthermore, in the igniter holding structure 10, the first resin part 5 and the second resin part 6 are completely separated by the peripheral wall part 35, so that the moisture absorbed by the second resin part 6 can be completely prevented from being transferred to the first resin part 5 and entering the combustion chamber 11.

[0104] Furthermore, in the igniter holding structure 10, the exposed surface S1 is formed as a portion of the peripheral wall 35 that is spaced apart from the first resin portion 5 by the second resin portion 6 on the inner side of the peripheral wall portion 35 and exposed to the connector insertion portion A1. Thus, by forming the exposed surface S1 for separating the first resin portion 5 and the second resin portion 6 by the peripheral wall portion 35, it is not necessary to separately provide the parts for forming the exposed surface S1 from the peripheral wall portion 35 (lower housing 3), thereby suppressing the increase in the number of parts and assembly time.

[0105] Furthermore, in the gas generator 100, the peripheral wall portion 35 has: an inner peripheral wall portion 351 with an exposed surface S1; and a near-front peripheral wall portion 353, formed below the inner peripheral wall portion 351 (near the front in the insertion direction) and extending outward from the exposed surface S1. In the igniter holding structure 10, the second resin portion 6 is provided in the near-front peripheral wall portion 353 in a manner that does not obstruct the insertion of the connector 200 into the connector insertion portion A1. Thus, by providing the second resin portion 6 in the near-front peripheral wall portion 353, which extends outward from the exposed surface S1, that is, by providing the second resin portion 6 in a wide space, the size of the connector insertion portion A1 can be sufficiently ensured, and the second resin portion 6 can be formed with a thicker wall. As a result, the strength of the second resin portion 6 can be improved. However, the location of the second resin portion in the igniter holding structure of this disclosure is not limited to this.

[0106] Furthermore, in the igniter holding structure 10, the connector guide surface S2, which is the surface of the second resin section 6 opposite to the connector 200, is formed to be flush with the exposed surface S1. As a result, the connector 200 can be guided smoothly into the connector insertion section A1 without being obstructed by the exposed surface S1 and without stopping in a state where it is further inward than the connector guide surface S2 (towards the exposed surface S1).

[0107] Furthermore, in the igniter holding structure 10, when the connector 200, which has a grounding terminal 204, is inserted into the connector insertion portion A1, the exposed surface S1 is formed to contact the grounding terminal 204. Thus, through the contact between the metal exposed surface S1 and the grounding terminal 204, the housing 1 with the exposed surface S1 is electrically connected to the grounding terminal 204. Consequently, when the housing 1 accumulates a charge, the charge flows to the grounding circuit via the grounding terminal 204 and the grounding wire 400. As a result, the charge on the housing is safely discharged, preventing malfunction of the igniter 4 caused by static electricity. However, the igniter holding structure of this disclosure may not correspond to a connector with a grounding terminal, and may also connect to a connector without a grounding terminal. That is, the exposed surface may not be formed to contact the grounding terminal of the connector.

[0108] It should be noted that in the ignition retaining structure disclosed herein, the exposed surface may not be formed on the aforementioned inner peripheral wall portion. The ignition retaining structure of this disclosure only requires that the first resin portion and the second resin portion be separated on the inner side of the peripheral wall portion; for example, the first resin portion and the second resin portion may be separated by the exposed surface being formed from the inner surface of the through hole.

[0109] [Variation Example 1]

[0110] Figure 5This is an axial cross-sectional view showing the vicinity of the igniter holding structure 10A in the gas generator 100A of Modified Example 1 of Embodiment 1. Hereinafter, the gas generator 100A and the igniter holding structure 10A will be described focusing on their differences from those of the gas generator 100 and the igniter holding structure 10, and detailed descriptions of the same components will be omitted, using the same reference numerals. Figure 5 As shown, in the gas generator 100A, in the mounting portion 34A, in addition to the through hole h1, a connecting hole h2 is formed, extending from the side of the first resin portion 5 across the peripheral wall portion 35 to the side of the second resin portion 6. Furthermore, in the igniter holding structure 10A, the first resin portion 5 and the second resin portion 6 are connected inside the connecting hole h2. The connecting hole h2 is provided in a connecting portion 352 forming an annular step in the peripheral wall portion 35, extending from the inner side to the outer side of the peripheral wall portion 35. Moreover, resin is filled through the connecting hole h2, connecting the first resin portion 5 and the second resin portion 6, forming them as a single unit. It should be noted that the portion of the peripheral wall portion 35 where the connecting hole h2 is formed is not limited to the connecting portion 352. Furthermore, multiple connecting holes h2 may be formed at equal intervals along the circumference of the peripheral wall portion 35.

[0111] According to the igniter holding structure 10A, the first resin part 5 and the second resin part 6 are connected inside the connecting hole h2. The resin inside the connecting hole h2 engages with the inner surface of the connecting hole h2. Therefore, the rotation of the first resin part 5 and the second resin part 6 relative to the mounting part 34A can be suppressed.

[0112] also, Figure 6 This diagram illustrates the manufacturing process of the ignition retaining structure 10A according to a variation of Embodiment 1. In the manufacturing method of the ignition retaining structure 10A, the injection molding of the first resin portion 5 and the second resin portion 6 can be completed in one step, which is consistent with... Figure 4The manufacturing method of the igniter retaining structure 10 described is different. In this example, the first resin part 5 and the second resin part 6 are also molded from the same resin material. First, in the preparation step S101, the igniter 4, the lower housing 3 including the mounting part 34A which is the object to be mounted on the igniter 4, and the resin material which is the raw material for the first resin part 5 and the second resin part 6 are prepared, and the igniter 4 and the lower housing 3 are arranged in the molding die. At this time, the connecting hole h2 is formed in the mounting part 34A. Next, in the resin part molding step S104, the resin material which is the raw material for the first resin part 5 and the second resin part 6 is melted, and the first resin part 5 and the second resin part 6 are injection molded in the mold and then solidified, thus injection molding the first resin part 5 and the second resin part 6 at the same time. In step S104, the molten resin material flows in from the resin material gate provided in the mold and solidifies. Through step S104, the first resin part 5 and the second resin part 6 are integrally molded. Here, as described above, the mounting portion 34A in this example has a connecting hole h2 that extends from the first resin portion 5 side of the igniter holding structure 10A to the second resin portion 6 side. Therefore, in step S104, resin material flowing into one of the first resin portion 5 and the second resin portion 6 sides within the mold can flow through the connecting hole h2 to the other side. By simultaneously molding the first resin portion 5 and the second resin portion 6 in one injection molding process, the processing time can be reduced. Furthermore, since only one gate is needed—either the gate for resin material flowing into the first resin portion 5 side or the gate for resin material flowing into the second resin portion 6 side—the manufacturing equipment can be simplified.

[0113] [Variation Example 2]

[0114] Figure 7 This is an axial cross-sectional view showing the vicinity of the igniter holding structure 10B in the gas generator 100B of Modified Example 2 of Embodiment 1. Furthermore, Figure 8 This is an axial cross-sectional view showing the state in which the gas generator 100B is connected to the connector 200B in Modification 2 of Embodiment 1. Hereinafter, the gas generator 100B, the igniter holding structure 10B, and the connector 200B will be described focusing on their differences from the gas generator 100, the igniter holding structure 10, and the connector 200. Since the same reference numerals are used for the same components, detailed descriptions are omitted. Figure 7 As shown, in the gas generator 100B, the connector guide surface S2, which is the surface of the second resin section 6 opposite to the connector 200B, is located inside the peripheral wall portion 35 of the exposed surface S1, and an engaging step portion E1 is formed between the exposed surface S1 and the connector guide surface S2. Furthermore, as... Figure 8As shown, the connector 200B applied to the igniter holding structure 10B is formed such that, when inserted into the connector insertion portion A1, the protrusion 203B and the grounding terminal 204B protrude outward from the peripheral wall portion 35.

[0115] During the insertion of connector 200B into connector insertion portion A1, protrusion 203B and grounding terminal 204B elastically deform inward while passing over connector guide surface S2. Furthermore, when insertion of connector 200B is complete, protrusion 203B and grounding terminal 204B elastically return to their original shapes. Thus, protrusion 203B engages with engaging step portion E1, and grounding terminal 204B contacts exposed surface S1. The engagement of protrusion 203B with engaging step portion E1 restricts connector 200B from being pulled out of connector insertion portion A1. In this way, according to igniter retaining structure 10B, the step formed between exposed surface S1 and connector guide surface S2 can be used to prevent connector detachment. It should be noted that in the above-described modifications 1 and 2, the peripheral wall portion 35 may also form a connecting portion 352 that connects the inner peripheral wall portion 351 and the near-front peripheral wall portion 353 with an annular inclined surface, or it may have a peripheral wall with an annular inclined surface extending from the lower end of the inner peripheral wall portion 351 to the bottom plate portion 32 instead of the connecting portion 352 and the near-front peripheral wall portion 353. Furthermore, the area covered by the first resin portion 5 and the second resin portion 6 of the peripheral wall portion 35 may also be... Figure 1 , Figure 2 The scope described.

[0116] [Variation Example 3]

[0117] Figure 9 This is an axial cross-sectional view showing the vicinity of the igniter holding structure 10C in the gas generator 100C of Modified Example 3 of Embodiment 1. Hereinafter, the gas generator 100C and the igniter holding structure 10C will be described focusing on their differences from those of the gas generator 100 and the igniter holding structure 10, and detailed descriptions of the same components will be omitted, using the same reference numerals. Figure 9As shown, in the igniter holding structure 10C, the exposed surface S1 is formed by an annular member 8, which is a different component from the lower housing 3. The annular member 8 can be fixed to the peripheral wall portion 35C by partial welding. For the peripheral wall portion 35C of the gas generator 100C, the inner peripheral wall portion 351 with the exposed surface S1 and the near-front peripheral wall portion 353 with the second resin portion 6 are formed with the same diameter, and a metal annular member 8 is provided on the inner side of the inner peripheral wall portion 351. The second resin portion 6 is spaced apart from the first resin portion 5 on the inner side of the peripheral wall portion 35C in such a way that a portion of the inner surface of the annular member 8 is covered by the first resin portion 5, and the remaining portion is exposed to the connector insertion portion A1, thereby forming the exposed surface S1. Since the exposed surface S1 is formed by the inner surface of the annular member 8, the near-front peripheral wall portion 353 is in a state that extends outward from the peripheral wall portion 35C than the exposed surface S1. Therefore, the second resin portion 6 located in the near-front peripheral wall portion 353 can be made into a thick wall.

[0118] <Implementation Method 2>

[0119] Next, as Embodiment 2, the case of applying the igniter holding structure of this disclosure to a gas generator for a seat belt retractor will be described. Figure 10 This is an axial cross-sectional view of a gas generator 100D equipped with an igniter holding structure 10D according to Embodiment 2. Hereinafter, the gas generator 100D and the igniter holding structure 10D will be described with a focus on the differences from the gas generator 100 and the igniter holding structure 10, and detailed descriptions of the same components will be omitted as they are labeled with the same reference numerals.

[0120] like Figure 10 As shown, the gas generator 100D includes: an igniter holding structure 10D, comprising an igniter 4, a first resin portion 5D, and a second resin portion 6; a metal collar 9; and a cover member 101. In Embodiment 2, the igniter holding structure 10D mounts the igniter 4 to the collar 9. Furthermore, in the igniter holding structure 10D, a combustion chamber 11D containing the gas generating agent 110 is formed by a portion of the first resin portion 5D. The gas generator 100D is configured to be embedded in a seatbelt retractor (not shown), and by activating the igniter 4, the gas generating agent 110 contained in the combustion chamber 11D is combusted, and combustion gases, as combustion products, are discharged, thereby retracting the slack seatbelt.

[0121] like Figure 10 As shown, the igniter 4 is mounted on the collar 9 while being held by the first resin part 5D. Furthermore, the second resin part 6 forms a connector insertion part A1, which serves as a space for inserting a connector (not shown) for supplying power (ignition current) to the igniter 4.

[0122] The collar 9 is a cylindrical metal component. The collar 9 is equivalent to a "mounting part". The collar 9 has: a through hole h1 through which the conductive pin 42 of the igniter 4 passes; and a peripheral wall portion 91 including the inner surface of the through hole h1. More specifically, the peripheral wall portion 91 has: a cylindrical hole-forming portion 910 including the inner surface of the through hole h1; a cylindrical inner peripheral wall portion 911 having an inner diameter larger than that of the hole-forming portion 910 and extending downward from the lower end of the hole-forming portion 910; and a near-front peripheral wall portion 913 having an inner diameter larger than that of the inner peripheral wall portion 911 and extending downward from the lower end of the inner peripheral wall portion 911. Due to the difference in the inner diameters of the inner peripheral wall portion 911 and the near-front peripheral wall portion 913, an annular step is formed between the inner peripheral wall portion 911 and the near-front peripheral wall portion 913. Furthermore, the lower end of the peripheral wall portion 91 opens into the space below the gas generator 100D. It should be noted that, in the following description, the inner side of the peripheral wall portion 91 and the inner side of the collar 9 refer to the inner side of the area surrounded by the peripheral wall portion 91, including the inner side of the through hole h1. Furthermore, the inner surface of the peripheral wall portion 91 refers to the inner-facing wall surface of the peripheral wall portion 91, including the inner surface of the through hole h1.

[0123] The first resin portion 5D, formed of resin material, includes: a retaining portion 51 for holding the igniter 4; and a cylindrical portion 52 integrally formed with the retaining portion 51, wherein the combustion chamber 11D is formed between the cylindrical portion 52 and the ignition portion 41 of the igniter 4. Figure 10 As shown, the retaining part 51 covers the lower part of the ignition part 41, the upper part of the conductive pin 42, and the inner surface of the through hole h1, and fixes the igniter 4 to the collar 9. The igniter 4 is held by the first resin part 5D with the ignition part 41 and the top end 421 of the conductive pin 42 on opposite sides across the through hole h1, and the conductive pin 42 is surrounded by the peripheral wall part 91. Furthermore, the cylindrical part 52 is formed as a cylinder with one end connected to the retaining part 51, and the other end of the cylindrical part 52 is closed by the cover member 101. A portion of the ignition part 41 (the portion not covered by the retaining part 51) is accommodated inside the cylindrical part 52, thereby forming a combustion chamber 11D between the ignition part 41 and the cylindrical part 52.

[0124] The second resin portion 6, forming the connector insertion portion A1, is formed in a cylindrical or annular shape on the inner side of the peripheral wall portion 91, covering the near-front peripheral wall portion 913. That is, the second resin portion 6 is provided spaced apart from the first resin portion 5D on the inner side of the peripheral wall portion 91, with a portion of the inner surface of the peripheral wall portion 91 exposed to the connector insertion portion A1. Thus, the inner surface of the inner peripheral wall portion 911 is exposed to the connector insertion portion A1, forming a metallic exposed surface S1. The exposed surface S1 is formed in a manner that covers the entire circumference of the inner periphery of the peripheral wall portion 91.

[0125] With the gas generator 100D assembled in the vehicle, the connector inserted into the connector insertion part A1 connects to the igniter 4, enabling power supply to the igniter 4. In this state, when a sensor (not shown) mounted on the vehicle detects a collision, power from an external power source is supplied to the igniter 4, and a high-temperature flame is emitted upwards from the ignition part 41. This ignites the gas generating agent 110 in the combustion chamber 11. Due to the pressure of the combustion gases from the gas generating agent 110, the cover member 101 cracks, and the combustion gases are discharged to the outside of the cylindrical part 52, retracting the slack seat belt. This restrains the occupant, protecting them from impact.

[0126] In the igniter retaining structure 10D of Embodiment 2, the second resin portion 6 is spaced apart from the first resin portion 5D on the inner side of the peripheral wall portion 91 of the collar 9 by forming a metal exposed surface S1 that exposes to the connector insertion portion A1 on the connector insertion portion A1. Therefore, it achieves the same effect as the igniter retaining structure 10 of Embodiment 1. That is, it is possible to suppress the resin from forming a thin wall on the inner side of the collar 9, which serves as the mounting portion. As a result, the strength of the resin on the inner side of the collar 9 can be ensured, and resin damage can be suppressed. In addition, it is possible to appropriately suppress the intrusion of moisture into the combustion chamber 11D caused by the resin forming a thin wall. As a result, the dry state of the gas generator 110 in the combustion chamber 11D is appropriately maintained, and the performance of the gas generator 100D is stable. Moreover, according to the igniter retaining structure 10D, by forming the combustion chamber 11D from a portion (cylindrical portion 52) of the first resin portion 5, the number of parts and assembly time can be reduced. Here, Figure 10 The arrow indicated by reference numeral M1 in the attached drawing represents the path of moisture intruding between the collar 9 and the first resin section 5D. In gas generators where the igniter is mounted to the collar (mounting section) through resin, moisture intrusion between the mounting section and the resin may also occur. In contrast, in the igniter holding structure 10D, a combustion chamber 11D is formed from a portion of the first resin section 5D; that is, the combustion chamber 11D is formed inside the first resin section 5D. Figure 10 As shown, this design prevents moisture from passing between the collar 9 and the first resin section 5D and entering the combustion chamber 11D. It should be noted that the igniter retaining structure 10D may also exclude the cover member 101.

[0127] [Variation Example]

[0128] Figure 11 This is an axial cross-sectional view of a gas generator 100E equipped with an igniter holding structure 10E according to a modified embodiment 2. Hereinafter, the gas generator 100E and the igniter holding structure 10E will be described focusing on their differences from those of the gas generator 100D and the igniter holding structure 10D. Detailed descriptions of the same components will be omitted, using the same reference numerals. Figure 11 As shown, the gas generator 100E includes: an igniter holding structure 10E, comprising an igniter 4, a first resin section 5E, and a second resin section 6; a collar 9; and a cup member 102. The igniter holding structure 10E differs from the igniter holding structure 10D in that the combustion chamber 11E containing the gas generating agent 110 is formed by a cup member 102, which is a different component from the first resin section 5E.

[0129] The first resin part 5E of the igniter holding structure 10E is equivalent to the first resin part 5 in the igniter holding structure 10 and the holding part 51 in the igniter holding structure 10D. In the state of holding the igniter 4, the igniter 4 is fixed to the collar 9. This configuration, in which the igniter holding structure 10E and the collar 9 are joined together, is called the igniter assembly 20.

[0130] The cup member 102 is formed as a bottomed cylindrical shape with a closed upper end and an open lower end. It is fixed to the collar 9 by riveting the lower end of the cup member 102 to the inner wall of the collar 9. A combustion chamber 11E is formed between the ignition part 41 (the part not covered by the retaining part 51) by accommodating a portion of the ignition part 41 inside the cup member 102. When the igniter 4 in the gas generator 100E is working, the pressure of the combustion gas of the gas generating agent 110 causes the upper end of the cup member 102 to crack, and the combustion gas is discharged to the outside of the cup member 102. As described above, the igniter retaining structure of this disclosure can also be applied to a gas generator in which a combustion chamber is formed by fixing the cup member to the igniter assembly.

[0131] The above description, in Embodiment 2, illustrates the application of the igniter holding structure disclosed herein in a gas generator for a seatbelt retractor. However, the structure in Embodiment 2, which mounts the igniter to a collar serving as a mounting part, can also be applied to a gas generator for an airbag. In this case, the igniter is mounted to the housing via the collar. For example, the igniter assembly described in the variation of Embodiment 2 can also be mounted to the housing. Figure 10 and Figure 11 In the gas generator shown, it is also possible to use it by connecting a connector with a grounding terminal so that the grounding terminal contacts the exposed surface. Alternatively, it can be used by connecting a connector that does not have a grounding terminal.

[0132] <Other embodiments>

[0133] The above description describes suitable embodiments of this disclosure; however, the various solutions disclosed herein can be combined with any other features disclosed herein. For example, in the above embodiments, the igniter holding structure was described as part of a gas generator, but it can also be applied, for example, to structures such as those disclosed in Japanese Patent Application Publication No. 2003-161599. Figure 1 As shown, this is an igniter assembly used by embedding a gas generator. Furthermore, the igniter holding structure disclosed herein can also be applied to a so-called two-stage gas generator having two igniters.

[0134] Explanation of reference numerals in the attached figures

[0135] 1. Outer shell

[0136] 2. Upper shell

[0137] 3····Lower shell

[0138] 34··· Installation Department

[0139] 35··· Zhoubi section

[0140] 351··Inner Peripheral Wall

[0141] 353··Proximal lateral wall portion

[0142] 4. Igniter

[0143] 41. Ignition Section

[0144] 42···Electrical pin

[0145] 5····First Resin Section

[0146] 51···Maintenance Department

[0147] 52···Tubular part

[0148] 6····Second Resin Section

[0149] 9. Collar (Installation Part)

[0150] 10. Igniter retaining structure

[0151] 20. Igniter Assembly

[0152] 100·· Gas Generator

[0153] 200 connector

[0154] h1···Through Hole

[0155] h2···Connecting hole

[0156] S1···Showing face

[0157] S2··· Connector inlet surface

[0158] A1··· Connector Insertion Section

[0159] E1··· Engaging Step Section

Claims

1. A gas generator comprising: An igniter having an ignition part including an ignition powder and a conductive pin extending from the ignition part; A metal mounting portion, wherein the metal mounting portion is formed with a through hole through which the igniter passes and a peripheral wall portion including the inner surface of the through hole for mounting the igniter. A first resin portion, disposed between the igniter and the mounting portion, holds the igniter in such a manner that the igniter and the tip of the conductive pin are located on opposite sides of each other across the through hole, and the conductive pin is surrounded by the peripheral wall portion; and A second resin portion is provided on the peripheral wall portion, and a connector insertion portion is formed on the inner side of the peripheral wall portion to serve as a space for inserting a connector that can be connected to the conductive pin. The peripheral wall portion has: an inner peripheral wall portion having a metal exposed surface that extends toward the connector insertion portion; and a near-front peripheral wall portion formed in the insertion direction of the connector relative to the connector insertion portion, which is closer to the front than the inner peripheral wall portion. The near-front peripheral wall portion has a larger inner diameter than the inner peripheral wall portion, and an annular step is formed between the near-front peripheral wall portion and the inner peripheral wall portion. The second resin portion is disposed on the near-front peripheral wall portion at a distance from the first resin portion on the inner side of the peripheral wall portion, such that the exposed surface is formed on the peripheral wall portion. The second resin portion forming the connector insertion portion is formed on the front side of the connector in the insertion direction, which is closer to the exposed surface than the exposed surface, and is flush with the exposed surface, or located on the inner side of the peripheral wall portion than the exposed surface.

2. The gas generator according to claim 1, wherein, The exposed surface is formed as a portion of the peripheral wall portion that is exposed to the connector insertion portion because the second resin portion is spaced apart from the first resin portion on the inner side of the peripheral wall portion.

3. The gas generator according to claim 1 or 2, wherein, In the mounting portion, in addition to the through hole, a connecting hole is also formed, extending from the first resin portion side across the peripheral wall portion to the second resin portion side. The first resin portion and the second resin portion are connected inside the connecting hole.

4. The gas generator according to claim 1 or 2, wherein, The near-anterior peripheral wall portion extends beyond the exposed outer side facing the peripheral wall portion. The second resin portion is provided on the near-front peripheral wall portion in a manner that does not obstruct the insertion of the connector into the connector insertion portion.

5. The gas generator according to claim 3, wherein, The near-anterior peripheral wall portion extends beyond the outer side of the exposed surface facing the peripheral wall portion. The second resin portion is provided on the near-front peripheral wall portion in a manner that does not obstruct the insertion of the connector into the connector insertion portion.

6. The gas generator according to claim 4, wherein, A stepped portion is formed between the exposed surface and the connector guide surface, such that the connector guide surface, which is the surface of the second resin portion opposite to the connector, is located inside the peripheral wall portion compared to the exposed surface. The stepped portion is configured such that, when the connector is inserted into the connector insertion portion, the connector is restricted from being pulled out of the connector insertion portion by engaging the protrusion protruding from the connector with the stepped portion.

7. The gas generator according to claim 1 or 2, wherein, The exposed surface is formed such that it can contact the grounding terminal when the connector with the grounding terminal is inserted into the connector insertion portion.

8. The gas generator according to claim 3, wherein, The exposed surface is formed such that it can contact the grounding terminal when the connector with the grounding terminal is inserted into the connector insertion portion.

9. The gas generator according to claim 1 or 2, wherein, The first resin portion includes: A retaining portion holds the igniter in such a manner that the ignition portion and the tip of the conductive pin are located on opposite sides across the through hole, and the conductive pin is surrounded by the peripheral wall portion; and The cylindrical portion is formed with one end connected to the retaining portion and the other end closed. The cylindrical portion internally accommodates a portion of the ignition portion, and a combustion chamber is formed between the cylindrical portion and the ignition portion to accommodate the gaseous propellant that burns through the operation of the ignition portion. The retaining part and the cylindrical part are integrally formed.

10. The gas generator according to claim 3, wherein, The first resin portion includes: A retaining portion holds the igniter in such a manner that the ignition portion and the tip of the conductive pin are located on opposite sides across the through hole, and the conductive pin is surrounded by the peripheral wall portion; and The cylindrical portion is formed with one end connected to the retaining portion and the other end closed. The cylindrical portion internally accommodates a portion of the ignition portion, and a combustion chamber is formed between the cylindrical portion and the ignition portion to accommodate the gaseous propellant that burns through the operation of the ignition portion. The retaining part and the cylindrical part are integrally formed.

11. The gas generator according to claim 7, wherein, The first resin portion includes: A retaining portion holds the igniter in such a manner that the ignition portion and the tip of the conductive pin are located on opposite sides across the through hole, and the conductive pin is surrounded by the peripheral wall portion; and The cylindrical portion is formed with one end connected to the retaining portion and the other end closed. The cylindrical portion internally accommodates a portion of the ignition portion, and a combustion chamber is formed between the cylindrical portion and the ignition portion to accommodate the gaseous propellant that burns through the operation of the ignition portion. The retaining part and the cylindrical part are integrally formed.

12. The gas generator according to claim 4, wherein, The peripheral wall portion has a connecting portion that connects the near-front peripheral wall portion and the inner peripheral wall portion. The second resin portion covers the connecting portion and the near-front peripheral wall portion on the inner side of the peripheral wall portion.

13. A gas generator comprising: An igniter having an ignition part including an ignition powder and a conductive pin extending from the ignition part; A metal mounting portion, wherein the metal mounting portion is formed with a through hole through which the igniter passes and a peripheral wall portion including the inner surface of the through hole for mounting the igniter. A first resin portion, disposed between the igniter and the mounting portion, holds the igniter in such a manner that the igniter and the tip of the conductive pin are located on opposite sides of each other across the through hole, and the conductive pin is surrounded by the peripheral wall portion; and A second resin portion is provided on the peripheral wall portion, and a connector insertion portion is formed on the inner side of the peripheral wall portion to serve as a space for inserting a connector that can be connected to the conductive pin. The peripheral wall portion has: an inner peripheral wall portion, on the inner side of which a metal annular member is provided; and a near-front peripheral wall portion, formed in the insertion direction of the connector relative to the connector insertion portion closer to the front than the inner peripheral wall portion. The inner peripheral wall portion and the near-front peripheral wall portion where the second resin portion is located are formed with the same diameter. The second resin portion is disposed spaced apart from the first resin portion on the inner side of the peripheral wall portion, such that a metal exposed surface is formed from the inner surface of the annular member and protrudes into the connector insertion portion. The second resin portion forming the connector insertion portion is formed on the front side of the connector in the insertion direction, which is closer to the exposed surface than the exposed surface, and is flush with the exposed surface.

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