JP4091848B2 - Airbag system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an airbag system using a bus system.
[0002]
[Prior art and problems to be solved by the invention]
An airbag system for protecting an occupant from an impact at the time of a vehicle collision is indispensable. However, the weight reduction of the airbag system is demanded from the demand for weight reduction of the entire vehicle. Recently, there has been a tendency for the number and type of airbags to increase, such as for driver seats, passenger seats, rear seats, and side collisions, so the demand for weight reduction of airbag systems has become greater. ing.
[0003]
In the current airbag system, an electronic control unit (ECU) connected to a power source (vehicle battery) and an impact detection sensor and individual gas generators (a gas generator and an airbag are installed in a module case). Are connected individually). FIG. 13 shows an image of the connection state between this ECU and each gas generator.
[0004]
As shown in FIG. 13, the ECU and the igniters of the individual gas generators (FIG. 14) are always connected by two conductors. Therefore, twice as many conductors as the total number of igniters are required. A large number of conductors account for a large portion of the weight increase in airbag systems. And, because of restrictions in assembling vehicle parts, the ECU and individual gas generators are not connected only by conductors, but are connected by connecting a plurality of conductors via a plurality of connectors. Further, the increase in weight due to the connectors and the increase in cost due to the increase in the number of connectors are also serious problems. Furthermore, the increase in weight due to the increase in the capacity of a capacitor incorporated in the ECU as a backup power source for operating all these igniters (when the wiring between the power source and the ECU is disconnected) is also large.
[0005]
Thus, attempts have been made to reduce the conductor weight required for connection between the ECU and each gas generator by using the bus system in an airbag system. An image of an airbag system using this bus system is shown in FIG.
[0006]
As shown in FIG. 1, a bus line composed of a plurality of annular wires passing through the ECU is provided, and each gas generator is connected to the bus line via two conductors (in some cases, three or more), and an airbag is provided. The system is configured. In the case of the airbag system as shown in FIG. 1, in order to operate only the necessary gas generators in response to the collision situation of the vehicle, each gas generator receives an information transmission from the ECU. A circuit and a capacitor are installed to supply the current that activates the igniter. When the bus system is used, although the total number of capacitors increases, the capacity and weight of each capacitor is reduced because the ECU and the igniters are distributed, so the backup in the airbag system of FIG. The weight of the capacitor is significantly reduced compared to the weight of the condenser, and when combined with a significant reduction in the amount of conductors used, the overall system will lead to a significant weight reduction. . As prior art using a bus system, Japanese Patent Laid-Open No. 2000-241098, Japanese Translation of PCT International Publication No. 2000-513799 and Japanese Patent No. 2707250 are known.
[0007]
The present invention introduces a bus system into an air bag system to achieve a significant weight reduction of the entire system, and can ensure the reliability and speed of operation similar to those of the conventional air bag, thereby obtaining high reliability. The problem is to provide a system.
[0008]
[Means for Solving the Problems]
(1) First Solution As a means for solving the above problems, the present invention accommodates an ECU connected to a power source and an impact detection sensor, and a plurality of gas generators and airbags connected to the ECU. A plurality of module cases,
A bus line consisting of a plurality of annular wires that pass through the ECU and supply and transmit current and required information is provided, and individual gas generators can be operated by a plurality of conductors branched from the bus line at the required part. Connected airbag system,
For each of the plurality of gas generators, one or two or more electric igniters provided with a heat generating part and an igniting agent in contact with the heat generating part are provided, and one or two or more igniters and bus lines have a plurality of conductors. In addition, for each igniter of each gas generator, an integrated circuit in which information for expressing a capacitor and a required function is recorded is installed.
From the point in time when the current for igniter ignition to one or more igniters is supplied via a capacitor in the igniter and the current supply time reaches a current value corresponding to 5% of the maximum current value, Provided is an airbag system in which the time is a time until a current value corresponding to 5% of the maximum current value is reduced and the time is within 500 μsec.
[0009]
The annular wire forming the bus line and the conductor connecting the bus line and the gas generator can be two, three, or four or more, but two are preferable from the viewpoint of simplifying the entire system.
[0010]
The ignition agent is not particularly limited, and a combination of a metal or the like and an oxidizing agent such as perchlorate is preferable, and a combination of a metal such as zirconium, titanium, or hafnium and a perchlorate is more preferable, and in particular, zirconium and perchlorate. A mixture with potassium acid (ZPP) is preferred. It is desirable that the ZPP is granular and the particle diameters of zirconium and potassium perchlorate are adjusted.
[0011]
The capacitance of the capacitor is preferably 24 μF or less, more preferably 12 μF or less, and even more preferably 6 μF or less.
[0012]
The maximum current value in the current supply time is a current value sufficient to ignite the igniting agent, and the igniting agent cannot be ignited at 5% or less of the maximum current value.
[0013]
In the case of a conventional airbag system, the current for operating the igniter is about 2 msec at 1.2 A from a relatively large capacity power source (battery), that is, a relatively low current is passed for a long time. The current waveform (vertical axis is current value (A), horizontal axis is time (μsec)) is rectangular.
[0014]
However, in the present invention, the current for operating the igniter is supplied from a capacitor having a relatively small capacity. Therefore, when the current is flowed at a relatively high current for a short time, the ignition agent is ignited smoothly, and the ignition energy itself is reduced. It is desirable because it is possible. When discharge is started when the waveform of the ignition current at this time (current value (A) on the vertical axis and time (μsec) on the horizontal axis) is time t = 0, the following formula (I):
i (t) = (V ₀ / R) × e ^{−t / CR} (I)
(Where, v ₀ is a capacitor charging voltage (V), R is a circuit resistance (Ω), C is a capacitor capacity (μF), t is a time (μsec), and i is a current (A)). Discharge waveform.
[0015]
In the case of the discharge waveform represented by the formula (I), the current value becomes larger than that of the conventional rectangular waveform, but the energization time is shortened, so that the ignition energy itself is greatly reduced.
[0016]
In the present invention, t (μsec) is a time during which a stable current supply is maintained after reaching a desired current value, and T (μsec) is a time from when the waveform starts rising until the current supply is stopped. ), The relationship between t and T (t / T) is preferably in the range of 0 ≦ t / T <0.2 or 0.5 <t / T <1.
[0017]
In the case of 0 ≦ t / T <0.2, it is close to the discharge waveform (waveform close to a triangle) when the electricity stored in the capacitor is directly applied to the heat generating part, and in the case of 0.5 <t / T <1 Is a waveform (trapezoid) when the discharge waveform is converted through a discharge waveform conversion circuit (hereinafter abbreviated as “waveform conversion circuit”) that converts the electric waveform accumulated in the capacitor into a signal waveform of the current for ignition agent ignition. Near the waveform).
[0018]
The current supply time is as described above, but is preferably within 200 μsec, more preferably within 100 μsec. The current value at this time varies depending on the resistance value of the heat generating portion of the igniter, and is determined by the presence or absence of the waveform conversion circuit, the configuration of the waveform conversion circuit, the particle size of the ignition agent, the shape of the heat generating portion, and the like.
[0019]
In the airbag system of the above invention, each of the igniters of the gas generators may be provided with a capacitor and an integrated circuit provided with a required function, and may further include a waveform conversion circuit. preferable. This waveform conversion circuit has a function of converting the discharge waveform represented by the formula (I) into a triangular wave or a trapezoidal wave. In addition, in order to provide a similar conversion function, the connection between the capacitor and the heat generating part is performed. A coil can be interposed in the circuit, and the discharge waveform conversion circuit can be provided in the integrated circuit from the viewpoint of simplifying the entire system.
[0020]
In the airbag system of the present invention, a circuit that prevents the igniter from malfunctioning due to noise generated outside the igniter, for example, a varistor (nonlinear resistance element) can be provided.
[0021]
In the above invention, as an integrated circuit in which information for expressing the required function is recorded, a function of detecting an abnormality of the heat generating part of the igniter in the gas generator, a function of identifying each of the plurality of gas generators, and a defect of the capacitor It is possible to use one in which information for expressing one or two or more functions selected from the function for detecting the color is recorded. Furthermore, it is desirable that a circuit that prevents the igniter from malfunctioning due to noise generated outside the igniter (a circuit that exhibits a noise prevention function) is provided in the igniter.
[0022]
The integrated circuit is provided with a basic function for operating an appropriate gas generator for occupant protection in response to a signal from the ECU according to the situation when the vehicle collides. In addition to the above, by adding the various functions described above, it is suitable for quality inspection of products at the time of shipment, improvement of workability at the time of assembly, improvement of safety at the time of practical use (during vehicle operation), etc. Become.
[0023]
(2) Second and third solving means As another means for solving the above problems, the present invention provides an ECU connected to a power source and an impact detection sensor, and a plurality of gas generators and an air connected to the ECU. A plurality of module cases in which bags are accommodated;
There is provided a bus line composed of a plurality of (for example, two, three, four or more, preferably two) annular wires that pass through the ECU and supply and transmit current and necessary information. An airbag system in which individual gas generators are operatively connected by a plurality of conductors branched at a site;
For each of the plurality of gas generators, one or two or more electric igniters including a heat generating part and an igniting agent in contact with the heat generating part are provided, and one or two or more igniters and a plurality of bus lines (for example, Connected by two, three, four or more, preferably two) conductors,
For each igniter of each gas generator, a capacitor, an integrated circuit in which information for expressing a required function is recorded, and a heat generating unit are installed on the same substrate, and the substrate is suspended.
An airbag system in which at least a capacitor and an integrated circuit in the substrate are not in contact with an igniter, and an electric current for igniter ignition is supplied to one or more igniters via the capacitor in the igniter. provide.
[0024]
As another means for solving the above problems, the present invention accommodates an electronic control unit connected to a power source and an impact detection sensor, and a plurality of gas generators and airbags connected to the electronic control unit. A plurality of module cases,
There is provided a bus line composed of a plurality of (for example, two, three, four or more, preferably two) annular wires that pass through the electronic control unit and supply and transmit current and necessary information. An air bag system in which individual gas generators are operatively connected by a plurality of conductors branched from a required part to
For each of the plurality of gas generators, one or two or more electric igniters including a heat generating part and an igniting agent in contact with the heat generating part are provided, and one or two or more igniters and a plurality of bus lines (for example, Connected by two, three, four or more, preferably two) conductors,
For each igniter of each gas generator, it has a capacitor installed on the same substrate and an integrated circuit in which information for expressing a required function is recorded, and the substrate is suspended.
Further, the substrate and the igniting agent are partitioned vertically by a header for supporting a conductive member that supplies and transmits current between the substrate and the heat generating portion, and the substrate is provided below the header, and the heat generating portion. Is provided above the header,
Provided is an airbag system in which the supply of ignition current to one or more igniters is performed via a capacitor in the igniter. Here, as long as the heat generating portion is provided above the header, the heat generating portion may be provided on the header surface or may be provided away from the header surface.
[0025]
In the airbag system of the above invention, each of the igniters of the gas generators may be provided with a capacitor and an integrated circuit provided with a required function, and may further include a waveform conversion circuit. preferable.
[0026]
In the above invention, an integrated circuit (and a waveform conversion circuit if necessary) is provided on one surface side of the substrate, and a capacitor (and a waveform conversion circuit if necessary) is provided on the other surface side. The part can be provided on either side, but it is desirable to provide the part on the same side as the integrated circuit because the circuit can be easily formed (soldering operation). Further, when providing the waveform conversion circuit, it is desirable to provide it in the integrated circuit from the viewpoint of simplifying the entire system.
[0027]
In the above invention, the substrate is fitted through the header that forms the igniting agent holding space together with the cup member that holds the igniting agent, the capacitor and the integrated circuit are located below the header, and the heat generating part is located above the header It can be made the structure which protrudes in contact with the ignition agent.
[0028]
When the heat generating portion is provided on the header, a method of welding and attaching a heating wire made of platinum / tungsten alloy, nickel / chromium alloy, etc. on the header, a foil made of the alloy, aluminum having an oxide film, glass, After being attached to an insulating substrate made of epoxy resin, phenol resin, polyimide, etc., a method of forming by etching, a method of forming by depositing a conductive material on a masked insulating substrate, or printing a conductive material on the insulating substrate It is formed by applying a method or the like.
[0029]
Thus, by providing the integrated circuit and the capacitor separately on both sides of the substrate, it is possible to make it more compact than the case where it is provided on one side. In addition, since the integrated circuit and the capacitor do not come into contact with the igniting agent by providing the igniting agent above the header and the substrate below the header, contamination of the capacitor and the integrated circuit by the igniting agent is prevented. There is no risk of malfunction.
[0030]
In the above invention, an integrated circuit and a capacitor (and a discharge waveform conversion circuit if necessary) can be provided on one side of the substrate, and the heat generating part may be provided on either side, It is desirable to be on the same side as the integrated circuit and the capacitor.
[0031]
In the above invention, the portion excluding the heat generating portion of the substrate is sealed with a glass fiber-containing thermoplastic resin, a thermosetting resin such as an epoxy resin, an organic or inorganic insulating material such as glass, and the heat generating portion is ignited. When a substrate having such a structure is used, a header for supporting a pin serving as an intermediate member for supplying and transmitting current and necessary information to an integrated circuit and a capacitor is used. A structure in which a substrate exists above can be used.
[0032]
In such a structure, the capacitor and the integrated circuit are protected, and the capacitor and the integrated circuit are not in contact with the igniting agent, so that the capacitor and the integrated circuit are prevented from being contaminated by the igniting agent.
[0033]
In the above invention, the integrated circuit, the heat generating portion, the connection portion between the capacitor and the bus line, and the heat generating portion of the igniter can be made of a conductor pattern formed on the substrate by etching. At this time, as shown in FIGS. 8 and 9, the conductor pattern forming the connection portion between the integrated circuit and the heat generating portion, the capacitor, and the bus line can have a total of six routes, two each. As the etching, wet etching, dry etching (plasma etching, sputter etching, reactive ion etching), photo etching, or the like can be applied.
[0034]
When such a conductor pattern is used, since the connection portion by soldering is reduced compared to the case where the integrated circuit, the heat generating portion and the capacitor are all connected by a conductor and the connection portion is soldered, the resistance value And the possibility of malfunction due to poor connection is reduced. Furthermore, by providing such a conductor pattern, wiring becomes easy, and manufacture becomes easy compared with the case where a bridge wire is provided as a heat generating part.
[0035]
(3) Fourth Solution As another solution of the above problem, the present invention includes an ECU connected to a power source and an impact detection sensor, and a plurality of gas generators and an airbag connected to the ECU. A plurality of module cases housed therein,
There is provided a bus line composed of a plurality of (for example, two, three, four or more, preferably two) annular wires that pass through the ECU and supply and transmit current and necessary information. An airbag system in which individual gas generators are operatively connected by a plurality of conductors branched at a site;
For each of the plurality of gas generators, one or two or more electric igniters including a heat generating part and an igniting agent in contact with the heat generating part are provided, and one or two or more igniters and a plurality of bus lines (for example, Connected by two, three, four or more, preferably two) conductors,
Provided is an integrated circuit in which information for expressing a function of detecting an abnormality in a heat generating part is recorded for each igniter of each gas generator, and an air bag system in which the heat generating part is installed. In addition, a capacitor can be provided together with the integrated circuit and the heat generating portion, and the detected abnormality of the heat generating portion of the igniter includes disconnection or poor contact between the heat generating portion and the ignition agent, or abnormality in the resistance value of the heat generating portion. It is done.
[0036]
As one of the requirements for the gas generator to operate normally, a good contact state between the heat generating part of the igniter and the igniting agent is required (the heat generating part and the igniting agent are in a pressure contact state), for example, When there is a gap between the heat generating part and the igniting agent, it may be considered that the igniting agent does not ignite or an ignition delay occurs when the igniter is activated. Moreover, it is conceivable that the same problem occurs when the heat generating part is disconnected or is about to be disconnected. For this reason, if the information for detecting the malfunction is recorded in the integrated circuit, the defective product can be eliminated at the time of shipment of the product, and the abnormality is detected at the time of practical use (during driving of the vehicle). By doing so, it becomes possible to exchange quickly.
[0037]
The detection theory of abnormalities in the heat generation part (thermal transient test; ACMunger published in p. 461-478 of Progress of International Pyrotechnic Semina in July 1980) is as follows. When the contact state is good, the amount of heat generated by passing a constant current moves to the igniting agent, so the temperature of the heat generating part does not rise so much, while the contact state between the heat generating part and the igniting agent is poor. In this case, since the heat transfer is small, the temperature rise of the heat generating portion is higher than usual, and thus the temperature change due to such a difference in the contact state is regarded as a resistance change, and the temperature coefficient of the metal resistance [r = r ₀ (1 + αΔT)] is used to detect the temperature of the heat generating part, and more specifically, when a weak current i that causes a temperature rise that does not ignite the igniting agent flows. Measure resistance r After that, the resistance R is measured when a current I that is 10 to 15 times the current i is passed (the temperature of the heat generating portion is about 50 to 100 ° C., but the igniting agent is not ignited at this level). , I, and R and r are compared to determine a resistance change due to a temperature change of the heat generating portion by a voltage change, and such measurement information is recorded in the integrated circuit.
[0038]
When detecting an abnormality of the heat generating part using the airbag system of the above invention, in a normal state where the gas generator does not operate, the current and instructions from the ECU are supplied / transmitted to the integrated circuit via the bus line, Based on the information recorded in the integrated circuit, a method of developing a function of detecting an abnormality in the heat generating part of the igniter is applied.
[0039]
(4) Fifth Solution The present invention provides, as another solution to the above problems, an ECU connected to a power source and an impact detection sensor, and a plurality of gas generators and airbags connected to the ECU. A plurality of module cases housed therein,
A plurality of (for example, two, three, or four or more) annular wires that pass through the ECU and supply and transmit current and required information are provided, and a plurality of branches branch from the bus line at the required portion. An air bag system in which individual gas generators are operatively connected by conductors of
For each of the plurality of gas generators, one or two or more electric igniters including a heat generating part and an igniting agent in contact with the heat generating part are provided, and one or two or more igniters and a plurality of bus lines (for example, Connected by two, three or more conductors)
Provided is an airbag system in which an integrated circuit for recording information for developing a discrimination function for each of a plurality of gas generators is installed for each igniter of each gas generator. Note that a capacitor and / or a heat generating portion can be provided together with the integrated circuit.
[0040]
In the above invention, it is preferable to record the information for realizing the identification function for each of the plurality of gas generators after the assembly of the gas generator, more preferably after the gas generator is assembled in the module case, the vehicle It is more preferable that recording is performed after attachment.
[0041]
Various types of gas generators for airbags, such as for a driver seat, for a passenger seat, for a side (for side collision), for a curtain, etc. are practically used. For example, a side gas generator is used for a driver seat. Attach a total of four, one for each passenger seat and two rear seats. For this reason, different information is recorded in each integrated circuit of the side gas generator for each of the driver's seat, the passenger seat, and the two rear seats. If it is recorded at the time or before assembly, the igniters and gas generators will have the same appearance, so different gas generators with different information recorded or different igniters should not be mistaken before assembly. It is necessary to store and transport separately, which is very complicated. Further, if the driver's seat for the passenger seat is mistakenly attached to the vehicle, when the operation information of the driver's seat airbag is issued from the ECU, a malfunction occurs in which the passenger seat airbag is inflated. It will be.
[0042]
Therefore, after recording the information to express the identification function for each gas generator, after assembling the gas generator (when the difference in gas generator can be recognized in appearance), incorporate the gas generator into the module case. After that (when the difference in the appearance of the module case can be recognized) or after it is installed in the vehicle, the gas generator can be stored, transported, managed, etc. It is prevented from occurring.
[0043]
When the identification function for each of the plurality of gas generators is developed using the air bag system of the above invention, the current and commands from the ECU are sent to the integrated circuit via the bus line in a normal state where the gas generators do not operate. A method of applying an identification function for each of a plurality of gas generators based on information supplied and transmitted and recorded in an integrated circuit is applied.
[0044]
(5) Sixth solving means The present invention includes, as another solving means for the above problems, an ECU connected to a power source and an impact detection sensor, and a plurality of gas generators and airbags connected to the ECU. A plurality of module cases,
There is provided a bus line composed of a plurality of (for example, two, three, four or more, preferably two) annular wires that pass through the ECU and supply and transmit current and necessary information. An airbag system in which individual gas generators are operatively connected by a plurality of conductors branched at a site;
For each of the plurality of gas generators, one or two or more electric igniters including a heat generating part and an igniting agent in contact with the heat generating part are provided, and one or two or more igniters and a plurality of bus lines (for example, Connected by two, three, four or more, preferably two) conductors,
Provided is an airbag system in which an integrated circuit in which information for expressing a capacitor and a function of detecting a malfunction of the capacitor is recorded is installed for each igniter of each gas generator. Note that a heat generating portion can be provided together with the capacitor and the integrated circuit.
[0045]
Information for realizing the function of detecting a defect of the capacitor includes information for measuring the pulse response or dielectric loss tangent, and information for confirming the mounting state (soldering state) of the capacitor on the substrate.
[0046]
After being mounted on the vehicle, the capacitor deteriorates over time due to repeated charging and discharging, but by recording information that can confirm the malfunction caused by this deterioration in an integrated circuit, it can be used in practical use (during vehicle operation). By detecting an abnormality, it will be possible to quickly replace it. Also, by recording information for confirming the soldering state, defective products can be eliminated at the time of product shipment.
[0047]
When the air bag system of the above invention is used to develop the function of detecting a malfunction of the capacitor, the current and the command from the ECU are supplied to the integrated circuit via the bus line in a normal state where the gas generator does not operate. A method of transmitting a function for detecting a malfunction of a capacitor based on information transmitted and recorded in an integrated circuit is applied.
[0048]
(6) Seventh Solution As another means for solving the above problems, the present invention includes an ECU connected to a power source and an impact detection sensor, and a plurality of gas generators and an airbag connected to the ECU. A plurality of module cases housed therein,
There is provided a bus line composed of a plurality of (for example, two, three, four or more, preferably two) annular wires that pass through the ECU and supply and transmit current and necessary information. An airbag system in which individual gas generators are operatively connected by a plurality of conductors branched at a site;
For each of the plurality of gas generators, one or two or more electric igniters including a heat generating part and an igniting agent in contact with the heat generating part are provided, and one or two or more igniters and a plurality of bus lines (for example, Two, three, four or more, preferably two) are connected by conductors, and each igniter of each gas generator is provided with an integrated circuit in which information for expressing a required function is recorded. And
Provided is an airbag system in which a circuit is provided in the igniter to prevent the igniter from malfunctioning due to noise generated outside one or more igniters.
[0049]
For example, a large current flows when the vehicle's cell motor starts, but if noise prevention means is not added, noise generated by this current (noise that causes unpleasant abnormal noise when listening to radio) is transmitted from the vehicle body. If the noise is transmitted in this manner, there is a high possibility that the igniter will malfunction. Therefore, as noise prevention means (a circuit that prevents the igniter from malfunctioning), a device that prevents current from flowing from the vehicle side to the igniter side, for example, a diode or a varistor (nonlinear resistance element) is attached. This prevents malfunction of the igniter described above.
[0050]
(7) Eighth Solution When the present invention has another two or more igniters for each of the plurality of gas generators in the airbag system of the present invention, as another solution to the above problem. Provided is an airbag system in which two or more igniters share one capacitor and an integrated circuit in which information for expressing a required function is recorded.
[0051]
In this way, in each of two or more igniters, one capacitor and an integrated circuit in which information for expressing a required function is recorded, and further, ignition powder ignition accumulated in the capacitors for each igniter provided as necessary. By sharing the discharge waveform conversion circuit that converts the signal waveform of the current for use, the entire system can be further reduced in weight. The discharge waveform conversion circuit may be incorporated in an integrated circuit.
[0052]
(8) Ninth Solution The present invention provides, as another solution to the above-mentioned problem, in the airbag system of the above invention, when two or more igniters are provided for each of a plurality of gas generators. Each igniter has a capacitor and an integrated circuit in which information for expressing the required function is recorded, and further has a pin for supplying and transmitting current and required information from the bus line to two or more igniters. An airbag system having two is provided.
[0053]
DETAILED DESCRIPTION OF THE INVENTION
The airbag system of the present invention achieves weight reduction of the entire system by using a bus line, and achieves certainty of operation of the system by the above solution. Hereinafter, embodiments including the first to ninth solving means will be described. It should be noted that the order of the solution means and the order of the embodiments do not mean to coincide.
[0054]
(1) First Embodiment As shown in FIG. 1, the airbag system of the present invention uses bus lines 10 and 11 made of two annular wires passing through the ECU. The ECU is connected to a power source (vehicle battery) (not shown) and an impact detection sensor. Further, the ECU is used as a backup when a conductor connecting the ECU and the power source is cut by an impact at the time of a vehicle collision. A capacitor is placed. In the airbag system of the present invention, a capacitor is arranged for each gas generator (igniter). Therefore, the backup capacitor may have a small capacity (that is, light weight), but is shown in FIG. The capacitor used as a backup in the conventional airbag system has a large capacity because it is necessary to operate all the gas generators by one when the lead wire is disconnected between the battery and the ECU. .
[0055]
The bus lines 10 and 11 and the gas generators in the required number of module cases (illustrated by black circles. A gas generator and an air bag are accommodated in the case) mounted in the vehicle are two. The individual gas generators are operatively connected by (or possibly more than three) conductors.
[0056]
In the airbag system shown in FIG. 1, as the gas generator in the module case shown by a black circle, those shown in FIGS. 2 and 3 can be used according to the number of igniters. FIG. 2 is a radial sectional view of one single type (igniter 21) igniter, and FIG. 3 is a radial sectional view of two dual types (igniters 31, 32) of igniter. FIG.
[0057]
In the single type, the igniter 21 is provided with two (or three or more in some cases) pins 21 a and 21 b and is connected to the bus lines 10 and 11 via the connector 25.
[0058]
In the dual type, the igniter 31 is provided with two (or three or more in some cases) pins 31a and 31b, and the igniter 32 is provided with two (or three or more in some cases) pins 32a and 32b. And connected to the bus lines 10 and 11 via connectors 35 and 36, respectively.
[0059]
In the gas generator shown in FIGS. 2 and 3, for example, the igniter 21 and the igniters 31 and 32 may be those shown in FIG. 4. FIG. 4 is a longitudinal schematic cross-sectional view of the igniter. Since the igniter 21 and the igniters 31 and 32 can have the same structure, the igniter 21 will be described below.
[0060]
A heat generating part is provided on the glass header, filled with a pyrotechnic (eg, ZPP) so as to be in pressure contact with the heat generating part, and a capacitor and information for developing the required function are recorded in the lower part. A substrate provided with an integrated circuit is provided. The integrated circuit, the heat generating portion, and the capacitor are each connected by two conductors, and the integrated circuit is further connected to the pins 21a and 21b via the conductors.
[0061]
In the integrated circuit, information is recorded so that at least a command from the ECU is received at the time of a vehicle collision and a necessary airbag can be inflated. Records information for expressing one or more functions selected from a function for detecting an abnormality in a heat generating part of an igniter in a generator, a function for identifying a plurality of gas generators, and a function for detecting a malfunction of a capacitor. Can be kept.
[0062]
The substrate on which the capacitor and the integrated circuit in the igniter 21 shown in FIG. 4 are installed can have the structure shown in the conceptual diagram of FIG. FIG. 6 shows pulse waveforms of the bus voltage, digital output, and charging voltage shown in FIG.
[0063]
A capacitor and an integrated circuit are provided on the substrate, and a waveform conversion circuit can be provided as necessary. The waveform conversion circuit itself can be incorporated into the integrated circuit.
[0064]
The integrated circuit and the capacitor on the substrate are connected to the bus lines 10 and 11 via pins 21a and 21b. The current and information supplied from the bus lines 10 and 11 are sent to the integrated circuit, then digitally output by an A / D converter (analog / digital converter), and sent to an MCU (Micro Computer Unit). In addition to sending instructions from the MCU to express charging control information, position identification information, disconnection detection information and resistance value change detection information of the heat generating part, the capacitor is charged, but in order to heat the heat generating part Not used.
[0065]
A varistor (nonlinear resistance element) is disposed as a noise prevention means between the circuits connecting the MCU and the heat generating part, and acts to prevent the igniter from malfunctioning due to noise generated outside the igniter.
[0066]
The heat generating part is in contact with the igniting agent and generates heat by supplying current only from the capacitor to ignite the igniting agent.
[0067]
Next, the operation of the airbag system of the present invention will be described with reference to FIGS.
[0068]
When the vehicle is in a normal driving state, via the bus line, from the ECU to the gas generator (integrated circuit installed in the igniter), disconnection detection information, resistance value change detection information of the heat generation part, and capacitor malfunction Detection information and detection information on whether there is an igniter including the identification function necessary for gas generator operation (in order to properly operate the necessary gas generators such as the driver's seat and front passenger seat at the time of collision) The detection information on whether or not igniters having the same identification function are correctly arranged, and whether or not the igniters having the same identification function are duplicated are sent, and it is detected whether or not there is any abnormality. The And when there is an abnormality, it is possible to replace parts early by notifying with a warning lamp or the like that operates in cooperation with the airbag system, so that safety can be ensured. In addition, the capacitor of each igniter is charged from the power source.
[0069]
When a vehicle equipped with an airbag system collides, information from the impact detection sensor is sent to the ECU, and the information from the ECU inflates the airbag via the bus lines 10 and 11 to ensure the safety of the occupant. It is sent to the required gas generator (integrated circuit installed in the igniter).
[0070]
In response to this information, the time required for the required current from the capacitor to reach a predetermined time (from when the current value corresponding to 5% of the maximum current value is reached to when the current value decreases to 5% of the maximum current value). In this case, when the discharge is started at time t = 0, the discharge represented by the formula (I) is generated when the heating section generates heat and the ignition agent is ignited and burned. 2 and 3 ignites and burns, and the gas generating agent ignites and burns to generate gas, which is discharged from the gas discharge port, and the gas generator is placed in the module case. The airbag housed together is inflated.
[0071]
(2) Second Embodiment The airbag system of the present embodiment is characterized by the structure of the substrate on which the integrated circuit and the like are installed, the installation state, and the like.
[0072]
First, the substrate structure will be described. As shown in FIG. 5, the substrate is provided with a capacitor, an integrated circuit in which information for expressing a required function is recorded, and a heat generating portion, and these can be installed on one surface or both surfaces of the substrate.
[0073]
As shown in FIG. 7, an integrated circuit and a heat generating portion are provided on one surface side of the substrate, and a capacitor is provided on the other surface side. In this structure, the capacitor and the integrated circuit are connected by two conductors through two holes, and the integrated circuit and the heat generating part are connected by two conductors. The integrated circuit is also connected to the bus lines 10 and 11 through two conductors, igniter pins, and the like.
[0074]
As shown in FIG. 8, an integrated circuit, a heat generating part, and a capacitor can be installed on one side of the substrate. The integrated circuit, the capacitor, and the heat generating part are connected by two conductors, respectively. The bus lines 10 and 11 are also connected through conductors, igniter pins, and the like.
[0075]
As shown in FIG. 9, the integrated circuit and the connecting portion between the integrated circuit and the heat generating portion, the capacitor and the bus line, and the heat generating portion shown in FIGS. 7 and 8 are formed by a conductor pattern formed on the substrate by etching. Can do. By using such a conductor pattern by etching, the connection work between the elements is facilitated.
[0076]
As shown in FIG. 10, it is preferable to cover and seal the portion excluding the heat generating portion with an insulating material such as an epoxy resin because the sealing resin acts as a protective film for the integrated circuit and the capacitor. Although the substrate shown in FIG. 7 is used in FIG. 10, the substrate shown in FIG. 9 can also be used, and the substrate is provided in a standing state on a glass header.
[0077]
Next, the installation state of the substrate will be described with reference to FIG. The substrate used in FIG. 11 is the same as that shown in FIG. 10. In the drawing, the igniting agent covering the heat generating portion is deleted, and the insulating material sealing portion is partially cut away.
[0078]
As shown in FIG. 11, the igniter 21 (with a form different from that of FIG. 4) uses the substrate shown in FIG. 10, so the substrate is provided in a standing state on the header, excluding the heat generating part. The part is covered with an insulating material such as epoxy resin, and the heat generating part is in contact with the ignition agent. The contact surface between the bottom surface of the substrate and the head is fixed with an adhesive.
[0079]
In this way, by suspending the substrate on the header, the space capacity for installing the substrate can be reduced as compared with the case where the substrate is laid flat, so that the igniter itself can be downsized. Further, since the integrated circuit and the capacitor in the substrate excluding the heat generating portion are not in contact with the ignition agent, contamination or the like is prevented.
[0080]
In the igniter 21 shown in FIG. 4, the substrate and the igniter are partitioned vertically by a glass header for supporting the pins 21a and 21b, and a capacitor and an integrated circuit are installed on the same substrate. Is suspended below the header. The heat generating portion is provided above the header (the surface of the header), and the heat generating portion and the substrate are connected by a conductor (two pins 22a and 22b). The heat generating portion is formed by applying a method of welding a heat generating wire made of platinum / tungsten alloy, nickel / chromium alloy or the like on the header.
[0081]
Also in the embodiment shown in FIG. 4, the integrated circuit, the capacitor, and the pins 21 a and 21 b can be connected by a conductive pattern by etching, and the heat generating portion and the integrated circuit can also be connected by a conductive pattern by etching.
[0082]
In this manner, by suspending the substrate under the header, the space capacity for installing the substrate can be reduced as compared with the case where the substrate is placed flat, so that the igniter itself can be downsized. Since the substrate and the igniting agent are not in contact with each other, contamination of the integrated circuit and the capacitor is prevented.
[0083]
The airbag system of the second embodiment operates in the same manner as the airbag system of the first embodiment.
[0084]
(3) Third to Fifth Embodiments As shown in FIG. 5, an integrated circuit and an igniter on which information for expressing a function of detecting an abnormality in a heat generating part of a capacitor and an igniter is recorded on a substrate The heat generating part is installed. Examples of the information include disconnection of the heat generating portion or poor contact between the heat generating portion and the ignition agent.
[0085]
By recording the above information on the integrated circuit, it is possible to quickly detect abnormalities such as disconnection or poor contact between the heat generating part and the igniting agent, so system replacement and occupant safety can be achieved by early replacement of parts. Can be increased.
[0086]
As shown in FIG. 5, the substrate is provided with a capacitor, an integrated circuit for recording information for realizing the identification function for each of the plurality of gas generators, and a heat generating portion of the igniter. It is desirable to record the information that causes the above identification function to be recorded after the gas generator is assembled, after the gas generator is assembled in the module case, or after being attached to the vehicle.
[0087]
By recording the identification function information on the integrated circuit in this way, management of product storage, transportation, etc. is facilitated, and malfunctions such as inflating an airbag different from the command from the ECU during practical use are prevented. Therefore, the reliability of the system and the safety of the passenger can be improved.
[0088]
As shown in FIG. 5, the substrate is provided with a capacitor, an integrated circuit in which information for expressing a function of detecting a defect of the capacitor is recorded, and a heat generating portion of the igniter. Examples of the information include information for measuring a pulse response or a dielectric loss tangent.
[0089]
By recording the above information on the integrated circuit, it is possible to quickly detect the malfunction of the capacitor. Therefore, the reliability of the system and the safety of the occupant can be improved by early replacement of parts.
[0090]
In the above third to fifth embodiments, the current required for the expression of each recorded information is supplied to the power source (vehicle battery) via the bus lines 10 and 11 and the two pins 21a and 21b of the igniter 21. ) To the integrated circuit, and a command for expressing the record information from the ECU is also transmitted to the integrated circuit through the same path as the current. And in the airbag system of 3rd-5th embodiment, it operate | moves similarly to the airbag system of 1st Embodiment.
[0091]
(4) Sixth Embodiment FIG. 12 shows a gas generator having two igniters, in which two heat generating parts are one capacitor, an integrated circuit in which information for expressing a required function is recorded, and necessary The waveform conversion circuit provided in accordance with is shared.
[0092]
When the gas generator has two igniters 31 and 32 as shown in FIG. 3, when only one of the igniters is operated due to the collision state of the vehicle, one of the igniters is operated first. In the case where the other is operated with a slight delay, or when two igniters are operated simultaneously, there are three possible modes of operation. The integrated circuit of the igniter in FIG. Information that can generate heat from the two heat generating portions is recorded in accordance with the contents of the command.
[0093]
The igniters 31 and 32 of the gas generator shown in FIG. 3 can have the structure shown in FIG. 5 or FIG.
[0094]
The airbag system of the sixth embodiment also operates in the same manner as the airbag system of the first embodiment, except that it operates in accordance with the above-described three command contents.
[0095]
The airbag system of the present invention includes an airbag inflator for a driver's seat, an airbag inflator for a passenger seat, an inflator for a side airbag, an inflator for a curtain, an inflator for a knee bolster, an inflator for an inflatable seat belt, and an inflator for a tubular system. It can be applied to various inflators (gas generators) such as inflators for pretensioners.
[0096]
【The invention's effect】
According to the airbag system of the present invention, by using the bus system, the weight of the entire airbag system can be greatly reduced, and the same operation performance as that of the conventional system can be ensured.
[Brief description of the drawings]
FIG. 1 is an image diagram of an airbag system of the present invention.
FIG. 2 is a radial sectional view of a gas generator (one igniter) used in the airbag system of the present invention.
FIG. 3 is a sectional view in the radial direction of a gas generator (two igniters) used in the airbag system of the present invention.
FIG. 4 is a longitudinal sectional view of an igniter used in the airbag system of the present invention.
FIG. 5 is a conceptual diagram of an igniter used in the airbag system of the present invention.
6 is a pulse waveform diagram of the bus voltage, digital output, and filling voltage shown in FIG.
FIG. 7 is a plan view of both sides of a substrate (each element is arranged on both sides) installed in an igniter used in the airbag system of the present invention.
FIG. 8 is a front view of a substrate (each element is arranged on one side) installed in an igniter used in the airbag system of the present invention.
FIG. 9 is a front view of another embodiment of a substrate (each element is arranged on one side) installed in an igniter used in the airbag system of the present invention.
FIG. 10 is a front view of a substrate installed in an igniter used in the airbag system of the present invention sealed with an insulating material.
FIG. 11 is a longitudinal sectional view of another embodiment of an igniter used in the airbag system of the present invention.
FIG. 12 is a conceptual diagram of another embodiment of an igniter used in the airbag system of the present invention.
FIG. 13 is an image diagram of a conventional airbag system.
FIG. 14 is a longitudinal sectional view of an igniter used in a conventional airbag system.
[Explanation of symbols]
10, 11 Bus line

Claims (7)

An electronic control unit connected to a power source and an impact detection sensor; and a plurality of module cases connected to the electronic control unit and containing a plurality of gas generators and airbags;
A bus line consisting of a plurality of annular wires that pass through the electronic control unit and supply and transmit current and required information is provided, and each gas generator is operated by a plurality of conductors branched from the bus line at the required location. An airbag system that is connected in a possible manner,
For each of the plurality of gas generators, one or two or more electric igniters provided with a heat generating part and an igniting agent in contact with the heat generating part are provided, and one or two or more igniters and bus lines have a plurality of conductors. In addition, for each igniter of each gas generator, an integrated circuit in which information for expressing a capacitor and a required function is recorded is installed, and further, ignition powder ignition accumulated in the capacitor for each igniter Including a discharge waveform conversion circuit that converts the signal waveform of the current for
From the point in time when the current for igniter ignition to one or more igniters is supplied via a capacitor in the igniter and the current supply time reaches a current value corresponding to 5% of the maximum current value, in the time until the time when decreased to a current value corresponding to 5% of the maximum current value, and the time is Ri der within 500 .mu.sec,
When the waveform of the current supplied from the capacitor starts discharging at time t = 0, the following equation (I): i (t) = (V ₀ / R) × e ^{−t / CR} (I )
(Where, v ₀ is a capacitor charging voltage (V), R is a circuit resistance (Ω), C is a capacitor capacity (μF), t is a time (μsec), and i is a current (A).)
An air bag system in which the discharge waveform represented by the formula (I) is converted by the discharge waveform conversion circuit .   2. The airbag system according to claim 1, wherein the bus line is composed of two annular wires. Claim 1 or 2 airbag system according discharging waveform converting circuit for converting a signal waveform of the current for ignition charge ignited accumulated in the capacitor for each igniter is present in the integrated circuit. The airbag system according to any one of claims 1 to 3 , wherein a circuit that prevents the igniter from malfunctioning due to noise generated outside the igniter is provided in the igniter. The airbag system according to any one of claims 1 to 4 , wherein a supply time of current to the heat generating portion is within 200 µsec. The airbag system according to any one of claims 1 to 4 , wherein a supply time of current to the heat generating portion is within 100 µsec. An integrated circuit in which information for expressing a required function is recorded has a function of detecting an abnormality of a heat generating part of an igniter in a gas generator, a function of identifying each of a plurality of gas generators, and a malfunction of a capacitor. The airbag system according to any one of claims 1 to 6 , wherein information for expressing one or more functions selected from the functions is recorded.

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