CN214523694U - Connecting structure of igniter assembly and lower shell - Google Patents

Abstract

The utility model belongs to the technical field of car air bag technique and specifically relates to a connection structure of ignition utensil subassembly and lower casing, including the injection molding body, the point explodes pipe, metal base, O shape circle, lower casing, adopt the injection molding body coupling between metal base and the point explodes the pipe, the lower extreme of injection molding body is equipped with the stair structure, is equipped with the step groove between the stair structure of injection molding body and the metal base, is equipped with the step hole down on the protruding structure in casing center, and the step hole inserts the step inslot, and O shape circle is located between the step hole of injection molding body stair structure and lower casing. Compared with the prior art, the utility model, through the structure that changes injection molding body and lower casing joint department for O shape circle takes place horizontal deformation in the installation and closely laminates at injection molding body, lower casing surface, plays the effect in sealed injection molding body and lower casing clearance. In addition, the tensile force generated by the wire harness is transmitted to the protruding structure of the lower shell through the O-shaped ring, and the problem that the tensile strength of the ignition assembly in the axial direction is insufficient is solved.

Description

Connecting structure of igniter assembly and lower shell

Technical Field

The utility model belongs to the technical field of car air bag technique and specifically relates to a connection structure of ignition utensil subassembly and lower casing.

Background

The automobile safety air bag module consists of a gas generator and an inflatable air bag. When the automobile collides and sends an ignition signal, the gas generator is instantaneously ignited and generates a large amount of gas. The gas generator can generate a great deal of gas, which is exhausted into the air bag through the exhaust holes distributed on the circumference of the gas generator shell, so that the air bag is expanded, and the purpose of protecting passengers from being injured is achieved. Because the gas generator is the core part of the automobile safety airbag, along with the increasing popularity of the automobile safety airbag, the requirements on the performance, the reliability and the price of the gas generator are higher and higher.

As shown in fig. 1, the gas generator is generally assembled from the following components: an upper shell and a lower shell which are connected in a buckling way. The upper and lower casings are usually joined by laser welding or friction welding to form a cylindrical sealed pressure vessel space. A number of exhaust holes 101 are formed in the side surface of the upper case 1 to outwardly exhaust gas when the gas generator is ignited. In order to ensure the space tightness of the pressure container, these vent holes 101 are sealed with a metal foil tape in a normal state. A cylindrical filter 3 is provided in a space surrounded by the upper case 1 and the lower case 2, and a gas generant is filled in a space formed between the filter 3 and the upper and lower cases. An igniter assembly for igniting the gas generant is disposed at a central location of the gas generator. The igniter assembly is composed of a transfer charge at the upper part, a transfer charge container 4 with a fire outlet at the side surface, an igniter tube 5 and a metal base 6 for fixing the igniter tube 5 and the transfer charge container 4. The metal base 6 is fixed to the opening of the gas generator lower case 2 by laser welding or resistance welding. The igniting tube 5 and the igniting powder container 4 are respectively fixed on the metal base 6 through flanges. In order to ensure that no leakage occurs between the squib injection-molded body and the metal base 6, an O-ring 7 is provided therebetween. When the gas generator works, the igniting tube 5 ignites the upper igniting powder, and then the igniting powder ignites the gas generating powder filled around. A large amount of gas generated by the combustion of the gas generant is filtered to remove solid residues by a filter and appropriately cooled, and then discharged into the airbag of the airbag module through the exhaust hole 101 formed in the side surface of the upper case 1 to inflate the airbag. Because of the complex structure of the gas generator, which has high requirements for performance and manufacturing process, the price of the gas generator often accounts for about 60% of the total cost of the entire airbag module.

Because the shape of the metal base is complex, the metal base can be machined by adopting a mechanical cutting method, so that the price of the metal cutting base is higher, and the influence on the cost of parts of the gas generator is larger. The elimination of machined metal bases has been a subject of research and development by many gas generator manufacturers in order to reduce the cost of the gas generator components as much as possible.

A pyrotechnic gas generator for an automobile airbag, publication No. CN204279333U, in which an igniter tube is directly injection-molded on a lower case, has been used in mass-produced products of a plurality of gas generator manufacturers. Although this structure can eliminate the expensive metal base which needs to be machined, the following two serious risks exist at the same time:

1) during the injection molding process, the sealing properties of the gas generator are affected because cooling of the injection molded body can form gaps between the injection molded body and the metal surfaces of the lower housing. When moisture in the atmosphere intrudes into the gas generator through the gap, the gas generant is deactivated, thereby affecting the deployment performance of the airbag module. For this purpose, gas generator manufacturers have applied a sealing compound to the metal surface of the lower housing before the injection molding process, in order to block the gap formed between the injection molded body and the metal lower housing. By doing so, not only is the production cost increased, but also the sealing problem of the injection molding body structure cannot be fundamentally solved.

2) Where the two legs of the squib pass through the injection molded body is a cylinder with a diameter of several millimeters. Because a gap is formed between the injection molding body and the surface of the metal lower shell, the tensile force generated by the wire harness embedded in the pocket of the injection molding body is directly applied to the section of the small cylinder at the central part of the injection molding body, and the problem of insufficient tensile strength of the small cylinder at the central part of the injection molding body can be caused. In addition, during the injection molding process, the tensile strength of the small cylinder at the central part is further reduced due to the cooling of the plurality of small cavities formed at the center of the small cylinder at the central part. For this reason, some gas generator manufacturers have designed a structure for preventing the injection molded body from falling off, but still cannot ensure that the tensile force generated by the wire harness is not directly applied to the small cylinder at the center portion.

In addition to the problems of insufficient sealing performance and insufficient tensile strength of the small cylinder in the center, the requirement for the cleaning degree of the whole metal lower shell is high because the squib is directly injection-molded on the metal lower shell. In addition, the lower shell with larger size and the detonation tube with smaller size are required to be put into an injection molding machine together during processing, the number of products capable of being injected at one time is small, and therefore the production efficiency is greatly reduced.

In order to effectively solve the problems of the sealing performance of the ignition device assembly of the injection molding body and the insufficient tensile strength of the small cylinder at the center of the injection molding body, the patent document with the application number of 201920960678.2 proposes that the igniter tube is directly injected on a small metal base. The metal base can be manufactured by forging and simple cutting due to its simple shape. Referring to fig. 2, a rectangular groove 9 into which the lower case can be inserted is formed between the injection molded body 8 and the metal base 6 for easy mounting on the lower case.

The combined state of the injection molded body and the lower case is shown in fig. 3. In order to connect the injection molded body and the lower case, a cylindrical protrusion is formed at the center of the lower case, and the injection molded body ignition device assembly is fixed to the central protrusion of the lower case by press-fitting. In order to solve the sealing problem between the injection molded body igniter assembly and the lower shell, an O-ring is mounted between the upper end of the central projection of the lower shell and the bottom of the rectangular groove of the injection molded body igniter.

During the press-fitting of the injection molded body ignitor assembly onto the central projection of the lower housing, the O-ring, which was previously seated on the bottom of the rectangular groove of the ignitor assembly, is subjected to compression and deformation. An O-ring deformed by compression can block leakage from both directions simultaneously: one is the possibility of leakage through the gap between the metal base and the injection molded body; the other is leakage from the inside of the gas generator through the upper part of the central projection of the lower housing. Additionally, the pulling force generated by the wire harness embedded in the pocket of the injection molded body ignitor assembly will be borne by the lower housing central boss and not directly on the injection molded body central small cylinder. The problem of insufficient tensile strength of the small central cylinder which may occur in the structure of the injection molded ignition assembly is thus completely solved.

However, there is a possibility that looseness may occur between the metal base of the igniter and the protrusion of the lower case to cause a failure in the sealing performance of the O-ring. To solve this problem, the O-rings must be compacted from top to bottom by internal components. Therefore, in the assembling process of the gas generator, the state of press-fitting the igniter assembly to the lower housing protrusion is highly required to ensure the reliability of the sealing performance.

Therefore, it is required to design a connection structure of an igniter assembly and a lower case, which can ensure sealing performance regardless of compaction of an O-ring, thereby improving reliability of the sealing performance.

Disclosure of Invention

The utility model aims at overcoming prior art's not enough, providing a connection structure of ignition utensil subassembly and lower casing, no matter whether the compaction of O shape circle, can both guarantee sealing performance to improve sealing performance's reliability.

In order to achieve the purpose, the utility model relates to a connection structure of ignition utensil subassembly and lower casing, including the injection molding body, the point is exploded the pipe, metal base, O shape circle, lower casing, adopt the injection molding body coupling between metal base and the point and explode the pipe, the lower extreme of injection molding body is equipped with the stair structure, is equipped with the step groove between the stair structure of injection molding body and the metal base, is equipped with the step hole down on the protruding structure in casing center, and the step hole inserts the step inslot, and O shape circle is located between the step hole of injection molding body stair structure and lower casing.

The O-shaped ring mounting groove is formed in the lower end surface of the injection molding body and located below the step structure of the injection molding body, and the O-shaped ring is mounted in the O-shaped ring mounting groove.

The upper surface of the O-shaped ring is attached to the surface of the step of the injection molding body, the lower surface of the O-shaped ring covers the gap between the injection molding body and the lower shell, the inner side of the O-shaped ring is attached to the outer surface of the injection molding body, and the outer side of the O-shaped ring is attached to the inner surface of the lower shell.

The metal base and the injection molding body are arranged on the lower shell of the single-stage gas generator.

The metal base and the injection molding body are installed on a lower shell of the two-stage gas generator, and the two detonation tubes are fixed on the metal base through the injection molding body.

The metal base is of a cup-shaped structure.

Compared with the prior art, the utility model, through the structure that changes injection molding body and lower body coupling department for O shape circle takes place horizontal deformation in the installation and closely laminates at injection molding body, lower casing surface, plays the effect in sealed injection molding body and lower casing clearance, in the installation, regardless of whether O shape circle the compaction all can take place horizontal deformation, and sealing performance can be guaranteed to the homoenergetic, thereby improves sealing performance's reliability. In addition, the tensile force generated by the wire harness embedded in the ignition component pocket is transmitted to the protruding structure of the lower shell through the O-shaped ring, and the problem that the tensile strength of the ignition component in the axial direction is insufficient is solved. The utility model discloses be convenient for equipment, processing have improved production efficiency, have reduced manufacturing cost and rejection rate.

Drawings

FIG. 1 is a schematic diagram of a prior art gas generator.

FIG. 2 is a schematic representation of a prior art injection molded body.

FIG. 3 is a schematic view of a prior art injection molded body in combination with a lower housing.

Fig. 4 is a schematic diagram of the present invention.

Fig. 5 is a schematic diagram of the action mechanism of the present invention.

Fig. 6 is a schematic view of a single-stage gas generator using the present invention.

Fig. 7 is a schematic diagram of a dual stage gas generator using the present invention.

Detailed Description

The invention will now be further described with reference to the accompanying drawings.

Referring to fig. 4, the utility model relates to a connection structure of ignition utensil subassembly and lower casing, including the injection molding body, the point is exploded the pipe, metal base, O shape circle, lower casing, adopt injection molding body 8 to be connected between metal base 6 and the point is exploded the pipe 5, the lower extreme of injection molding body 8 is equipped with the stair structure, is equipped with step groove 10 between the stair structure of injection molding body 8 and the metal base 6, is equipped with step hole 21 on the lower casing 2 center protruding structure, and step hole 21 inserts in the step groove 10, and O shape circle 7 is located between 8 stair structures of injection molding body and the step hole 21 of lower casing 2.

The utility model discloses in, O shape circle mounting groove sets up at the lower extreme surface of injection molding body 8 and is located the below of 8 stair structures of injection molding body, and O shape circle 7 is installed in O shape circle mounting groove.

Referring to fig. 5, when the injection molded body 8 is pressed downwards into the protruding structure of the lower shell 2, the O-ring 7 contacts with the vertical part of the stepped hole 21 of the lower shell 2 and deforms transversely, the upper surface of the O-ring 7 is attached to the stepped surface of the injection molded body 8, the lower surface of the O-ring 7 covers the gap between the injection molded body 8 and the lower shell 2, the inner side of the O-ring 7 is attached to the outer surface of the injection molded body 8, and the outer side of the O-ring 7 is attached to the inner surface of the lower shell 2, so that the sealing between the injection molded body 8 and the lower shell 2 is realized, and the intrusion of moisture from the outside of the generator to the inside is effectively blocked. Since the sealing between the injection molded body 8 and the lower case 2 is achieved by the transverse deformation of the O-ring 7, whether the O-ring 7 is compacted from the top down or not will not have any effect on the sealing performance of the O-ring 7. Therefore, the reliability of the sealing performance of the generator product is greatly improved.

Adopt the utility model discloses a single-stage pie firework formula gas generator is shown in figure 6, and its assembly process is as follows: 1, a metal base 6 and an injection molded body 8 are arranged on a protruding structure of a lower shell 2 of the single-stage gas generator, and the metal base 6 is of a cup-shaped structure. In the press-fitting process, the O-ring 7 is deformed transversely, thereby achieving sealing between the igniter assembly and the lower case. 2, pressing the transfer powder container 4 on the metal base 6. 3, the filter 3 is placed into the lower case 2. 4, the transfer agent container 4 is filled with transfer agent 41. 5, the gas generant 112 is filled in the loading chamber 11. 6, the upper cover 111 of the loading chamber is pressed on the transfer powder container 4. And 7, pressing the upper shell 1 on the lower shell 2, and welding the upper shell and the lower shell.

Adopt the utility model discloses a doublestage cake form firework formula gas generator is shown in figure 7, and metal base 6, injection molding 8 are installed on doublestage gas generator's lower casing 2, and two igniter tubes 5 are fixed on a metal base 6 that is cup-shaped structure through injection molding 8. The flat portion of the metal base 6 can be made thicker, so that the bending deformation of the metal base 6 at the time of the explosion of the gas generator can be reduced. By this means, interference between the second stage gas generant container 12 and the first stage booster container 13 can be prevented upon ignition. The metal base 6 of the two electric explosion tubes 5 can be processed by a simple method, two metal cutting bases are omitted, and the part cost of the two-stage gas generator can be greatly reduced. Meanwhile, the production cost can be greatly reduced due to the characteristic of convenient processing and assembly.

The assembly process of the two-stage pie-shaped pyrotechnic gas generator is as follows: 1, pressing the igniter assembly on the central protrusion structure of the lower case 2. In the press-fitting process, the O-ring 7 is deformed laterally, thereby achieving sealing between the igniter assembly and the lower case 2. 2, the first-stage cartridge 13 is press-fitted on the metal base 6. 3, the second stage cartridge 14 is press-fitted to the metal base 6. 4, the filter 3 is placed into the lower case 2. 5, the first stage transfer case 13 is filled with transfer charge 41. 6, the first-stage loading chamber 15 is filled with gas generant. A one-way blocker 16 is placed over the gas generant composition 7. 8, press fitting the second stage loading cup 17 onto the second stage cartridge 14. 9, the second-stage loading chamber 12 is filled with gas generant. 10, the second stage chamber 12 is capped and press fitted into the second stage cup 17. 11, the upper case 1 is press-fitted to the lower case 2, and welding between the upper and lower cases is performed.

The utility model discloses a change the structure of injection molding body and lower casing connection department for O shape circle takes place transverse deformation in the installation and closely laminates at injection molding body, lower casing surface, plays the effect in sealed injection molding body and lower casing clearance, in the installation, no matter whether O shape circle the compaction all can take place transverse deformation, and sealing performance is guaranteed to the homoenergetic, thereby improves sealing performance's reliability.

The tensile force generated by the wire harness embedded in the pocket of the ignition device assembly is transmitted to the protruding structure of the lower shell through the O-shaped ring, and the problem that the tensile strength of the small cylinder at the central part of the ignition device assembly is insufficient in the axial direction in the original structure is solved.

The utility model discloses because adopt O shape circle to reach required sealed requirement, so the requirement is not high to metal base's clean degree. That is, quality assurance becomes easy and the rejection rate is greatly reduced.

The utility model discloses can abolish the metal base that the shape is complicated, need process through complicated cutting completely, help reducing gas generator spare part cost, especially to doublestage gas generator, owing to can save two metal bases that need complicated cutting process simultaneously, so can the processing cost of greatly reduced spare part cost and gas generator product.

Because the utility model discloses a little will the point explode the pipe and mould plastics on little metal base rather than directly moulding plastics on the lower casing bigger, so do not need to put into the injection molding machine to the lower casing bigger together, the part size of putting into the injection molding machine is less, can several ignition utensil subassemblies of simultaneous processing, production efficiency will obtain great promotion.

Claims (6)

1. The utility model provides a connection structure of ignition utensil subassembly and lower casing, includes injection molding, detonation tube, metal base, O shape circle, lower casing, adopts injection molding (8) to be connected between metal base (6) and detonation tube (5), and the lower extreme of injection molding (8) is equipped with stair structure, its characterized in that: a step groove (10) is formed between the step structure of the injection molding body (8) and the metal base (6), a step hole (21) is formed in the central protruding structure of the lower shell (2), the step hole (21) is inserted into the step groove (10), and the O-shaped ring (7) is located between the step structure of the injection molding body (8) and the step hole (21) of the lower shell (2).

2. A connecting structure of an igniter assembly and a lower case as set forth in claim 1, wherein: the O-shaped ring mounting groove is formed in the lower end surface of the injection molding body (8) and located below the step structure of the injection molding body (8), and the O-shaped ring (7) is mounted in the O-shaped ring mounting groove.

3. An igniter assembly and lower case connecting structure as set forth in claim 1 or 2, wherein: the upper surface of the O-shaped ring (7) is attached to the step surface of the injection molding body (8), the lower surface of the O-shaped ring (7) covers the gap between the injection molding body (8) and the lower shell (2), the inner side of the O-shaped ring (7) is attached to the outer surface of the injection molding body (8), and the outer side of the O-shaped ring (7) is attached to the inner surface of the lower shell (2).

4. A connecting structure of an igniter assembly and a lower case as set forth in claim 1, wherein: the metal base (6) and the injection molding body (8) are arranged on the lower shell (2) of the single-stage gas generator.

5. A connecting structure of an igniter assembly and a lower case as set forth in claim 1, wherein: the metal base (6) and the injection molding body (8) are installed on the lower shell (2) of the double-stage gas generator, and the two detonation tubes (5) are fixed on the metal base (6) through the injection molding body (8).

6. An igniter assembly and lower case connecting structure as set forth in claim 4 or 5, wherein: the metal base (6) is of a cup-shaped structure.

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