Adaptive output inflator

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

Background of the invention The present invention generally relates to an inflator for use when inflating an inflatable restraint airbag cushion used, for example, to protect the passengers of an automobile from impact. In particular, the present invention relates to an inflator that outputs expansion gas in multiple stages (multiple levels) or multiple stages (multiple levels), which applies to factors such as one or more accident situations and passenger situations. It is used to output the expansion gas.

【0002】

Known to protect vehicle occupants with cushions and bags, such as "airbags," which are inflated or expanded by gas when the vehicle is hit by a sudden deceleration, such as in a collision. Is. In this system, airbags are usually housed in an uninflated, folded state to minimize space requirements. At system startup, the cushion begins to inflate in approximately a few milliseconds with the gas produced or supplied by a device commonly referred to as an "inflator".

【0003】

Various types of inflator devices for inflating airbags used in inflatable restraint systems in the art have already been disclosed. Certain types of known inflator devices are adapted to obtain expansion gas from a flammable explosive gas generator capable of generating a sufficient amount of gas to inflate the airbag upon ignition.

【0004】

Such inflator devices generally include various components, namely pressure vessels for burning explosive gas generators, and various filter devices for properly adjusting the expansion medium before flowing into the corresponding airbag cushion. It has or incorporates various components, including an expansion medium processor and a diffuser to assist in proper orientation of the expansion medium with respect to the corresponding airbag cushion.

【0005】

Considering that operating conditions may change and desirable operating characteristics may change, there are requirements and demands for "adaptive" inflator devices and corresponding inflatable restraint systems. According to the adaptive inflator device, for example, depending on selected operating conditions such as ambient temperature, presence or absence of passengers, presence or absence of seat belts, and deceleration of the vehicle, such as the amount of expansion gas, supply, and rate of supply. The output parameters can be changed selectively and appropriately.

【0006】

Although such adaptive systems are desirable, they typically require additional components as part of the corresponding inflator device, resulting in larger dimensions, higher costs, and weight of the inflator device. Is not desirable because it becomes heavy. For example, the various dual-stage inflator devices currently available that have been proposed appear to be based on the principle of accommodating two separate inflators together. For this reason, these combined inflators typically have two separate pressure vessels, two sets of filters or expansion gas treatment elements, one for each output from each pressure vessel, and again the output from each pressure vessel. It has two separate diffusers, one for each. Therefore, it is difficult to provide an adaptive inflator that can fully meet the size, cost, and weight restrictions in modern vehicle design, especially for driver side applications.

【0007】

For this reason, there is still a demand for an adaptive inflator device that has a simple design and structure and can meet the dimensional requirements in the vehicle, especially in the driver's side application. Therefore, a main object of the present invention relates to an improved inflator, an inflatable restraint system, and a method of operation related to or corresponding to these. A particular object of the present invention solves one or more of the problems described above.

【0008】

A main object of the present invention is at least a portion by an airbag inflator having a housing defining a first chamber containing a predetermined amount of first gas generating agent that can be ignited to produce a first combustion product in a dormant state. Will be achieved. The first chamber has a second chamber containing a predetermined amount of a second gas generating agent that can be ignited to produce a second combustion product in a dormant state. The second chamber has an outlet orifice designed to open to allow the second combustion product to communicate with the contents of the first chamber. The airbag inflator also has a first igniter that is operatively associated with the first chamber and a second igniter that is operatively associated with the second chamber.

【0009】

Conventional techniques cannot provide the desired simple design for inflators designed to provide multiple output level performances. In particular, conventional techniques have not been able to provide an output adaptive inflator and its associated inflatable restraint system, especially with a set of components common to each stage of two or more operating stages, such as a pressure vessel. It is not possible to provide an inflator for the driver's side inflatable restraint system equipment that utilizes a common set of components such as filters and associated seals, and thus each of the inflators. It is unavoidable to require separate components for the operating stage.

【0010】

Furthermore, the present invention relates to an adaptive spark airbag inflator. The inflator includes a first chamber, a second chamber, an insulator, a first igniter, and a second igniter. In particular, the first and second chambers of the inflator each contain a predetermined amount of explosive that can be ignited to produce combustion products. The second chamber has an outlet orifice designed to open so that the combustion products produced by the combustion of the explosive contained in the second chamber communicate with the contents of the first chamber. This outlet opening is normally closed to prevent material from flowing into the second chamber. The insulator is effective in avoiding the automatic ignition of the explosive contained in the second chamber during thermal contact with the combustion products formed during the ignition of the explosive contained in the first chamber. It is arranged around the second room. The first igniter is operatively associated with the first chamber and the second igniter is operatively associated with the second chamber.

【0011】

Furthermore, the present invention relates to a method of operating an airbag inflator. The inflator has a housing that defines a first chamber containing a predetermined amount of first gas generating agent that can be ignited to produce a first combustion product in a dormant state. The first chamber houses a second chamber containing a predetermined amount of second gas generating agent that can be ignited to produce a second combustion product in the inspiratory state. The second chamber has an outlet orifice designed to open to allow the second combustion product to communicate with the contents of the first chamber. Further, the inflator has a first igniter that is operatively associated with the first chamber and a second igniter that is operatively associated with the second chamber. The method of the present invention includes a step of operating at least one of a first ignition device and a second ignition device.

【0012】

It should be noted that in this specification, detecting or detecting "presence or absence of a passenger" means detecting and detecting the size, weight, and / or position of a specific passenger in consideration. .. The inflator "output" or expansion gas "output" refers to the output parameters of the inflator performance such as the amount of expansion gas, supply, and supply rate. Also, in power-adaptive inflators, the inflator output generally depends on selected operating conditions such as ambient temperature, presence or absence of passengers, presence or absence of seat belts, deceleration of the vehicle. Other objectives and advantages will be apparent to those skilled in the art by reading the detailed description below, along with the claims and drawings.

【0013】

Detailed description of the invention 1 and 2 show a power-adaptive driver-side inflator assembly of one embodiment of the invention, which is shown entirely by reference numeral 10. Hereinafter, the present invention will be described with reference to the airbag inflatable restraint system equipment on the driver's side, but broadly, for example, an airbag assembly on the auxiliary seat side or a side collision for an automatic vehicle including a van, a pickup truck, and an automobile. The present invention can be applied to other types or types of airbag assemblies, including for airbag assemblies.

【0014】

The inflator assembly 10 is generally cylindrical in shape and has a housing structure 12 formed of two structural elements: a lower shell or base portion 14 and an upper shell or diffuser cap portion 16. It is preferably made of aluminum and is properly connected or fastened, for example by inertia welding. Housing 12 is generally in the shape of a flat, disc-shaped circular cylinder, typically or generally as a ratio of length (indicated by "L") to its diameter (indicated by "D"). It is 0.5 or less. A housing having such a dimensional shape can be assembled aesthetically as it can most conveniently correspond to the shape of the steering wheel of the vehicle.

【0015】

The diffuser cap portion 16 is generally shaped like an inverted bowl and has an upper wall 20 and a cylindrical side wall 22. The side wall 22 has a plurality of gas outlet ports 24 that are spaced apart from each other, preferably a plurality of gas outlet ports 24 that are spaced apart from each other substantially equally. The base portion 14 has a first mounting opening and a second mounting opening indicated by reference numerals 26 and 30, respectively, and their uses will be described in detail later. The base portion 14 also has a peripheral bracket 32 that extends radially outward from the housing 12 to the passenger's vehicle to be protected from injury caused by the impact of a collision. Helps to form the interface mounting used to mount the inflator assembly 10.

【0016】

The housing 12 defines a central first chamber 34, which is generally cylindrical. The first chamber 34 typically contains, in the form of explosives, a predetermined amount of a first gas generating agent 36 consisting of a fibrous metal amine nitrate known for use in, for example, an airbag inflator, an oxidant and a binder. Enclose or contain. The first gas generating agent 36 is surrounded by a filter assembly 40, which has a combustion screen or filter 42 consisting of a multi-layer or multi-roll metal screen and a filter damper pad 44. The filter 42 is surrounded by an adhesive seal foil 46, which generally is in close proximity to the inner surface of the side wall 22 and preferably seals and seals the gas generator 36 in the inflator assembly 10 to generate gas. The agent is protected from the surrounding conditions including moisture. The inflator assembly 10 also has a retainer 50 and an annular base damper pad 52, which hold the components of the inflator assembly in a relatively proper arrangement and prevent unwanted flow formation within the inflator assembly. Act as a structurally appropriate means of doing so.

【0017】

At a location within the first chamber 34, the housing 12 is fitted through the first mounting opening 26 with the first ignition assembly, shown in its entirety by reference numeral 54. The first ignition assembly 54 mounts the ignition cup 56 containing the ignition agent 60, the first ignition device or the detonator 62, and the first ignition assembly 54 to the housing 12, as is known in the art. Or in the form of a known spark igniter having a detonator adapter or detonator holder 64 for fitting and a detonator seal 66 for sealing the detonator 62 and the adapter 64. As shown, the ignition cup 56 forms an interior space 74 in the form of a generally concave member with a cap 70 and a cylindrical side wall 72. Ignition cup 56 is made of a gas impermeable material such as metal, the side wall 72 of the cylindrical gas outlet cage spaced between multiple office 76, preferably has a gas outlet orifice 76 spaced between substantially equal .. These gas outlet orifices 76 are usually covered (when the inflator is in the pre-actuated state) with a pressure sensitive cover or pressure barrier 80, such as a seal foil wrap with adhesive known in the art, from which material is used. Is prevented from passing through. As is known, the cover 80 is selected to open or tear when a predetermined pressure is applied from the internal space of the ignition cup 56.

【0018】

At start-up, the ignition of the igniter 60 normally raises the pressure in the interior space 74 of the cup, followed by the cover 80 tearing or opening as expected, releasing the ignition product produced by the combustion of the igniter 60. The ignition assembly 54 can be passed through the outlet orifice 76 to the gas generating agent 36 contained in the first chamber 34. The resulting contact with the ignition product, or contact between the ignition product and the gas generating agent, causes the gas generating agent to be ignited and reacted, and the gas thus produced passes through the filter 42 and seals. It breaks the foil 46, passes through the gas outlet port 24 (as indicated by arrow A), and flows from the inflator assembly 10 into the corresponding airbag assembly (not shown). In practice, the ignition product may be brought into contact with the gas generating agent thermally, physically, or thermally and physically.

【0019】

Actually, the ignition assembly 54 is formed by arranging the ignition cup 56 containing the ignition agent 60 so as to cover the ignition device 62 and the holder 64, and is arranged in the mounting opening 26. The ignition assembly 54 is then connected to the housing 12 by welding the holder 64 to the base portion 14 at the mounting opening 25.

【0020】

The first room 34 accommodates or includes the second room 82. The second chamber 82 attaches or adapts the generator cup 84 containing the gas generating agent, which is referred to as the second gas generating agent 86 in the present application, the second igniter or the detonator 90, and the second chamber 82 to the housing 12. It has a second detonator adapter 92 and a second detonator seal 94 for sealing the second detonator adapter 92 and the detonator 90. As shown, the generator cup 84 forms an interior space 102 in the form of a generally concave member with a cap 96 and a cylindrical side wall 100.

【0021】

The second gas generating agent 86 is typically in the form of an explosive and may be the same or different in composition, shape, size and shape as compared to the first gas generating agent 36. The generator cup 84 is made of, for example, a metal gas impermeable material, the cylindrical side wall 100 of which is a plurality of spaced gas outlet orifices 104, preferably a plurality of gas outlet orifices 104 which are approximately equally spaced. Has.

【0022】

The outer wall of the cylindrical side wall 100 is covered or wrapped with a pressure sensitive insulating barrier material 106. It is desirable that such an insulating barrier material 106 can perform several functions of one or more. First, the insulating barrier material 106 is from at least a part of the effect of the operation of the first ignition assembly 54 and the effect of combustion of the first gas generating agent 36 contained in the first chamber 34 to the second chamber. The 82 and its contents, such as the second gas generating agent 86, can be insulated. It should be noted that the operation of the first ignition assembly 54 and the reaction of the first gas generating agent 36 generally cause a temperature rise as a result.

【0023】

As described above, the second chamber 82 is housed or contained within the first chamber 34, so that the second chamber 82 is generally very close to the ignition assembly 54 in order to minimize the required space. It is preferable to have. Therefore, if the insulating wall material 106 is mounted, the temperature of the second chamber 82 reaches the automatic ignition temperature of the gas generating agent stored or contained therein as a result of contact with the reaction product of the first chamber 34. Alternatively, by preventing it from reaching, the adverse impact on the second chamber 82 of an unwanted but possible temperature rise can be minimized or avoided.

【0024】

Further, the insulating barrier 106 usually has more gas outlet orifices 104 (when the inflator assembly 10 is in the pre-actuated state), thus preventing the material from passing through the gas outlet orifices. The insulating barrier material 106 is generally selected to open or tear when a predetermined pressure is applied from inside the second chamber 82.

【0025】

The insulating wall material can take various forms such as a foil with an adhesive containing glass fiber. Further, if desired, a separate barrier material can be used to fill, supply, or provide various mechanisms of the insulating barrier material. For example, the present invention provides an insulating barrier material from one or more materials to provide insulating properties or benefits and one or more additional materials to normally close or shield the gas outlet orifice. It can also be configured.

【0026】

It should be noted that the inflator assembly of the present invention can provide operating conditions according to the selected operating conditions required or desired for the particular inflatable restraint system equipment and application. In particular, the inflator assembly of the present invention produces a large amount of expanded gas, a generation rate, or both in the event of a vehicle accident or collision in order to consider one or more situations such as the presence or absence of a passenger as described above. Is actuated to change appropriately. The adaptability of such inflator performance is obtained from the inflator, which is the subject of the present invention, which has two ballistically isolated chambers for the gas generating agent. The inflator, which is the subject of the present invention, exhibits several distinct expansion performance characteristics.

【0027】

For example, the inflator assembly is actuated to perform a first stage release, which ignites the first igniter 60 to produce a combustion product, which passes through the first gas generator 34. As described above, the first gas generating agent 36 is ignited, the second igniter 90 is not operated or ignited, or the gas generating agent 86 contained in the second chamber 82 is not reached or is operated. The expansion gas is generated at the first output level without doing so. It should be noted that such operation should provide a minimal or reduced inflator output, which is desirable, for example in the case of a low speed collision. It is also possible to operate the inflator assembly of the present invention, such as operating both the first ignition device 62 and the second ignition device 90, respectively.

【0028】

Also, all operations and ignitions of the first igniter, the second igniter, the first gas generator and the second gas generator (desirably in response to a high speed collision or a very dangerous collision) Simultaneous operation / ignition of the first and second igniters (to inflate and deploy the airbag cushion in the air), or may include substantially simultaneous operation / ignition. Sequential operation and ignition of the first igniter and the second igniter (desirably in the event of a relatively less dangerous vehicle collision) may be included. Furthermore, in such sequential operation / ignition, there is a time lag or delay between the operation / ignition of the first detonator and the operation / ignition of the second detonator, and the ignition of the first gas generator and the ignition of the second gas generator. The time lag or delay between and is adjusted to meet certain requirements in a particular inflatable restraint system facility, as will be apparent to those skilled in the art. Thus, these inflator cushions are generally output-adaptive, specifically tailored to one or more selected operating conditions, such as the temperature around the vehicle, the presence or absence of passengers, the use of seat belts, and the deceleration of the vehicle. Suitable for use as an inflator.

【0029】

When the igniter 90 is activated, the igniter 90 releases the ignition product, which ignites the gas generating agent 86 to produce a reaction product, which is in the internal space 102 of the cup. The pressure is increased and then the insulating barrier 106 is breached or opened as expected, the reaction product passes through the outlet orifice 104 (as indicated by arrow B), followed by the gas outlet port 24. Allows flow from the inflator assembly 10 into the corresponding airbag cushion (not shown) through.

【0030】

The inflator assembly 10 is an expansion product produced from both the first and second chambers rather than a separate filter assembly for each chamber or stage of the inflator common to various conventional dual stage type inflator devices. A single filter assembly 40 is adopted or used to filter or perform a process such as cooling. Further, by using one filter assembly without using two or more filter assemblies, the need for mounting a plurality of filter assembly seals is reduced, or the need itself is eliminated. In addition, the inflator assembly 10 has one diffuser that does not require a separate diffuser for each chamber or stage contained therein.

【0031】

By reducing the number of parts in the inflator assembly, the inflator design can be simplified, the manufacturing and production costs can be reduced, and the weight of the assembly can be reduced, and thus the assembly requires in the vehicle. The space volume can be reduced. The design of the system can be simplified, for example, by using a single filter or filter assembly to filter the expansion products of expansion emissions from both the first and second chambers, thus simplifying the design of the system. The space inside the inflator assembly can be used well. Therefore, generally adaptively designed inflator assemblies are typically sized for system equipment, especially for driver-side inflatable restraint systems that are sized to be housed in or within the handle column or handle hub. It can be easily accommodated within a defined and provided frame.

【0032】

Broadly, the invention is not limited to the use of specific or specific gas generating agents. The present invention can also be practiced with a wide range of gas generating agents that meet flame temperature requirements, stability requirements, filtration characteristic requirements, toxic requirements, corrosive requirements, and gas generation requirements, as will be apparent to those skilled in the art. Further, the present invention is particularly carried out in combination with the use of an explosive gas generating agent known in the art, for example, including an explosive composed of a transition metal amine nitrate, an oxidizing agent and a binder, as is known in the art. Also suitable for.

【0033】

It should be noted that gas generating agents such as explosives, which are useful in carrying out the present invention, can take various suitable and desirable forms including, for example, various extruded forms and granular materials. Also broadly, the invention is not limited to any particular or specific form of gas generating agent.

【0034】

Further, the inflator assembly of the present invention may utilize a gas generator in physical form or physical parameter with the same composition as both the first gas generator and the second gas generator, and the broad practice of the present invention is not limited. .. For example, the first gas generator burns relatively slowly, eventually causing the corresponding airbag cushion to expand slowly or slowly, and the second gas generator burns relatively quickly, resulting in the corresponding air. It is particularly desirable to have a rapid or rapid expansion rate for the bag cushion, which is desirable if the corresponding vehicle encounters a relatively dangerous collision or accident. Such a difference in performance is achieved by using gas generators having different compositions as the first gas generator and the second gas generator. Alternatively or additionally, the first gas generating agent and the second gas generating agent may be in physically different forms, or may be, for example, physically different parameters in terms of shape and dimensions. For example, in order to provide a material that burns quickly, or a material that burns more quickly, it is desirable to adopt a material form having a large surface area.

【0035】

The present invention will be described in more detail with the following examples showing or simulating various aspects involved in the practice of the present invention. It should be noted that all changes within the ideas of the present invention should be protected and therefore the present invention should not be construed as limited to the following examples.

【0036】

Example The operation of the output adaptive inflator, which is the subject of the present invention, was experimentally confirmed using an airbag inflator assembly having a steel housing similar to that of the inflator assembly 10 described above. The test inflator was 36.4 mm high and 80 mm in diameter. The first chamber contains about 43 g of an explosive gas generator consisting of a transition metal amine nitrate, an oxidant and a binder in the form of multiple annular cylinders, so-called "extrudlets". About 6g was stored in the two rooms. The extrudlet is in the shape of a cylinder with holes extending in the longitudinal direction. The explosive gas generator extendlet used in this example had a length and diameter of 3.175 mm (0.125 inches) and an inner diameter of 1.067 mm (0.042 inches). The ignition cup in the first chamber contained about 2.6 g of granular ignition agent.

【0037】

The test inflator device contained a steel mesh filter. The gas spilled from the explosive passed through the filter and spilled from the inflator assembly through a gas outlet port radially arranged around the inflator on the side wall of the diffuser portion.

【0038】

The test inflator was mounted in a 60 liter sealed tank, which was equipped with a pressure transducer to measure changes in gas pressure within the tank produced by the inflator. Since the entire part of the inflator for passing the outflow gas was housed in the closed tank, the volume inside the closed tank was completely shielded from the outside air. Since an electronic ignition line was connected to each detonator of the test inflator, different compartments of the test inflator could be properly ignited separately or simultaneously, or with a selected time delay between each ignition operation. .. The tank achieved by the test inflator assembly by operating the test inflator in a form of (A) igniting only the first chamber and (B) igniting both the first chamber and the second chamber substantially simultaneously. The pressure is shown in Figure 4 as a function of time. Line A shows the results obtained when only the first chamber is ignited, and line B shows the results obtained when both the first chamber and the second chamber are ignited substantially at the same time.

【0039】

In this example, when both the first chamber and the second chamber were ignited at the same time, the pressure inside the closed tank rose faster and the maximum tank pressure was higher than when only the first chamber was ignited. .. It should be noted that in relation to special deployment conditions such as collisions with relatively low risk and small passengers to be protected, the airbag cushion is loose and gradually obtained when only the first chamber is ignited. Deployment that progresses to is preferable. On the other hand, for other applications such as high-speed collisions where the passenger is seated in the proper position to be properly protected by airbags, the rapid pressure obtained when both chambers are ignited at the same time. Ascending is suitable.

【0040】

Also, the rate of increase and maximum pressure obtained when igniting one or both chambers of the inflator are both appropriate in the amount, size, shape, and type of explosive contained in the igniter chamber. It can be selected or changed by changing to, or by selectively changing other design parameters. In addition, the pressure characteristics over time for the inflator are tailored to the requirements or needs for specific airbag system equipment to adequately reduce occupant injury and optimize occupant protection.

【0041】

Although not specifically disclosed herein, the inventions exemplified herein are feasible without some elements, parts, processes, configurations, or components.

【0042】

Thus, the present invention provides an inflator suitable for providing multiple output levels, which has a significantly simpler design than previously available inflators. According to at least one embodiment of the invention, a common set of components such as a pressure vessel, a filter, and a corresponding seal for each stage of two or more operating stages is utilized, thereby providing for each inflator stage. An output-adaptive inflator is provided, especially for use as an inflator for driver-side inflatable restraint system equipment, which can avoid the need to mount separate components. This simplifies the system design and allows efficient use of space inside the inflator assembly. Thus typically, or for system equipment, especially for driver-side inflatable restraint systems, sized to accommodate in the column of the steering wheel, in the column, in the hub, or in the hub. It is generally easy to accommodate adaptive inflator assemblies of these designs within the frame normally sized and provided.

【0043】

Although not specifically disclosed herein, the inventions disclosed herein by way of example can be practiced without some elements, parts, processes, configurations, or components. In the above detailed description, the present invention has been described in connection with a preferred embodiment, and some details have been described for purposes of illustration, but the present invention may be implemented as another embodiment or described herein. It will be apparent to those skilled in the art that the details disclosed in (1) can be significantly modified without departing from the basic principles of the present invention.

[Simple explanation of drawings]

[Figure 1]

It is a partial side sectional view of the airbag inflator of one Example of this invention. [Figure 2]

It is a partial side sectional view of the airbag inflator of FIG. 1, but it is simplified here by not showing, for example, a gas generator, an igniter, and a seal. [Fig. 3]

It is a figure which shows the airbag inflator shown in FIG. 2 substantially seen from the direction of an arrow along line 3-3 of FIG. [Fig. 4]

It is a graph which showed the tank pressure as a function of the time achieved in the inflator assembly used in the example.