JPH0834308A - Air bag device - Google Patents

Abstract

PURPOSE:To accurately prevent the malfunction of an air bag device with a simple constitution, at the time it is connected to or disconnected from a vehicle, by providing a prohibiting means by which a switch means is prohibited from becoming a closed condition until the detection signal of a signal generating means is received. CONSTITUTION:In an air bag device 1, it is detected through a grounding terminal 80a whether or not the air bag device 1 has been fitted to a steering wheel 60. In this case, the electrification to a squib 2 that has been formed in an inflator is prohibited by a collision judging circuit 107 until the air bag device 1 is brought into the condition that it is fitted to a steering wheel 60 from the condition that it is not fitted, so that the, erroneous explosion is not caused. Since the start of the air bag device 1 or the electrification to the squib 2 is prohibited for a prescribed time after the air bag device 1 has been fitted, the,erroneous explosion of the inflator due to the shock when it is mounted or fitted can be surely prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupant protection airbag device mounted on a vehicle, and more particularly to an airbag device including an inflator and an ignition circuit for operating the inflator, which is mounted on the vehicle. The present invention relates to an airbag device that can prevent malfunction of the device.

[0002]

2. Description of the Related Art Conventionally, an air bag, an inflator for deploying the air bag, a collision discrimination device for discriminating a vehicle collision, and an ignition device for igniting the inflator according to the result of the collision discrimination device are integrally mounted. Bag devices are known. When mounting such an airbag device on a vehicle, a connector of a relay device for electrically energizing the airbag device and the vehicle side is usually connected and then fixed to a steering wheel or the like. This is because, in a general airbag device, after the airbag is mounted on the steering wheel, the connector can be connected in a space of the steering wheel so that the vehicle side and the airbag device can be relayed. Because it will disappear.

In the air bag device mounted on the vehicle in the energized state as described above, the collision determination device for detecting the deceleration is integrated with the air bag device.
There is a possibility that the collision determination unit of the airbag device may erroneously determine the acceleration due to the impact when it is mounted on the steering wheel. In addition, when a worker or the like drops the airbag device to give acceleration to the airbag device in the process of assembling to the steering wheel, the collision determination circuit may erroneously determine as in the above. There is a risk that the normal operation of the may be impaired. Therefore, conventionally, as disclosed in, for example, Japanese Patent Laid-Open No. 63-212148, an air bag device having a preventive device for preventing the above-mentioned erroneous explosion by using a mechanical switch has been adopted. That is, the following operation is performed by inserting the mechanical switch in the ignition starting power supply circuit that energizes the inflator from the power supply. First,
When the air bag device is energized before it is attached to the steering wheel or when the air bag device is detached from the steering wheel, the mechanical switch holds the open state, and the ignition drive current to the inflator is maintained. Do not supply. Further, after the airbag device is mounted on the steering wheel, the switch is closed and the ignition drive current is supplied to the inflator.

[0004]

However, when the mechanical switch is formed in the ignition circuit from the power source to the inflator to prevent the accidental explosion of the airbag device as described above, the performance is very high. Expensive mechanical switches are required. This is because the mechanical switch is arranged in the ignition circuit as described above, and therefore, after the airbag device is mounted on the steering wheel, if the switch does not operate normally, it keeps the open state or the closed state. If the vehicle accidentally falls into the open state, the airbag device may not operate normally as designed at the time of a vehicle collision. Further, when the airbag is deployed at the time of a vehicle collision, the ignition current for igniting the inflator is a large current. When the mechanical sensor malfunctions due to this large current, it is possible that the ignition current is not sufficiently supplied to the inflator. In order to avoid such a situation, a mechanical sensor having very good performance has been adopted. However, this has resulted in increasing the cost of the airbag device as a whole.

Further, in the conventional airbag device, the mechanical switch cannot cope with an impact at the moment of mounting the airbag device on the steering wheel. That is, before the airbag device is attached to the steering wheel, the inflator will not be activated even if the impact of a worker dropping the airbag device causes an erroneous collision determination. However, a mechanical switch detects the airbag installation after the moment when the airbag device is attached to the steering wheel,
It is conceivable to cancel the prohibition of the ignition drive of the inflator. In such a case, in actuality, when the switch is closed before the airbag device is finally mounted and fixed on the steering wheel, and then a shock is applied to the airbag device during assembly, The airbag device may perform an operation contrary to the designed operation.
It goes without saying that the mechanical switch capable of accurately detecting the mounting moment as described above is very expensive.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an airbag device capable of accurately preventing malfunction with a simple structure when the airbag device is attached to or detached from a vehicle.

[0007]

In order to solve the above problems, an airbag apparatus according to the present invention is provided with an airbag, an inflator for supplying high pressure gas to the airbag, and a predetermined ignition power source when energized. A vehicle airbag device including an ignition circuit for operating the inflator, the ignition circuit being housed in a conductive case, and being integrally mounted on a steering wheel, which is connected in series to the ignition circuit. And switch means capable of switching between an open state and a closed state by a control signal, and a conduction means for electrically connecting the case and the downstream of the switch means,
By attaching the airbag device to the steering wheel, contact means for electrically contacting the steering wheel and the case, and electrical contact between the steering wheel and the case by the contact means are applied to a voltage of the case. It is characterized by comprising a signal generating means for detecting as a change and generating a detection signal, and a prohibiting means for prohibiting the switch means from being in a closed state until the detection signal is received from the signal generating means. .

Further, the steering wheel is a ground, and the potential of the case drops to a predetermined value by the contact of the case with the steering wheel, and the signal generating means detects a change in this voltage. The airbag device according to claim 1 may be adopted. Further, the steering wheel is electrically connected to a predetermined power source, and the contact of the case with the steering wheel raises the potential in the case by a predetermined value, and the signal generating means detects a change in this voltage. The airbag device according to claim 1 may be adopted.

Further, the vehicle airbag device integrally mounted on the steering wheel detects deceleration of the vehicle and outputs a signal corresponding to the deceleration, and the deceleration. Based on the deceleration signal from the detection means, a determination means for determining whether or not the vehicle is in a collision state, and when the determination means determines that the vehicle is in a collision state, the switch means is turned on. Alternatively, the airbag device according to claim 2 or claim 3 may be employed in which the ignition current is supplied.

The detection signal detected and output by the signal generation means is input to the discrimination means, and when the discrimination means detects the input of the detection signal, the operation of the switch means is permitted. The airbag device according to claim 4 may be adopted. A deceleration switch, which is mechanically responsive to deceleration due to the collision when the vehicle collides, and whose contacts are closed, is connected in series to the ignition circuit. You may make it employ | adopt the airbag apparatus of description.

Further, there is provided a timer means for prohibiting the switch means from being in an open state until a predetermined time elapses after the detection signal is detected by the discriminating means. You may make it employ | adopt the airbag apparatus in any one of Claim 6. Further, while the prohibiting means prohibits the switch means from being in an open state, a predetermined warning light is turned on or blinks to display the warning light. You may make it employ | adopt the airbag apparatus of description.

Further, when the timer means prohibits the switch means from being opened for a predetermined time, a predetermined warning light is turned on or blinks to display. The airbag device described in 7 may be adopted. In addition, the switch means,
The airbag device according to any one of claims 1 to 9, wherein the airbag device is formed of a transistor connected in series to the ignition circuit.

Further, when the determination means determines that the vehicle is in a collision, the switch means is closed to apply an ignition current to the inflator to deploy an airbag for protecting an occupant. Claim 1 characterized by
Alternatively, the airbag device according to any one of claims 10 to 10 may be adopted. Further, the signal generating means is configured so that the base current of the transistor electrically connected to the case is grounded in response to the mounting of the airbag device on the steering wheel, so that the emitter current of the transistor is grounded. Alternatively, at least one of the collector currents is changed, and this change is transmitted to the discrimination means as the detection signal. The airbag device according to any one of claims 4 to 11 is adopted. May be.

Further, in the conduction means, in the board on which the ignition circuit is formed, a conduction portion extending from a downstream side of the switch means in the ignition circuit is formed in a screw tightening portion for installing the board in the case. 13. The fixing member electrically connects the conducting portion and the case when the substrate is installed in the case with the fixing member having conductivity.
You may make it employ | adopt the airbag apparatus as described in either.

Further, the contact means is configured such that when the case is installed on a conductive mounting bracket for mounting the case to the steering wheel with the conductive fixing member, the fixing member is The airbag device according to any one of claims 1 to 13 may be adopted in which the case and the bracket are in electrical contact with each other.

Further, the prohibiting means unconditionally opens the switch means until a detection signal indicating that the airbag device is mounted on the steering wheel is input to the determining means. 15. The closing of the switch means is prohibited by a signal from the discriminating means for a predetermined time after the detection signal is input to the discriminating means. You may make it employ | adopt the airbag apparatus as described in either.

[0017]

The operation of the airbag device constructed as described above will be described below. As described above, the mounting of the airbag device on the steering wheel is detected by the change in the voltage in the conductive case. Based on the signal indicating the change in the voltage, the prohibition of conduction of the switch means is held. At this time, in order to monitor the voltage change,
The signal generating means can be configured with an inexpensive and simple configuration such as a transistor, and it is not necessary to employ a particularly high-performance detection switch, mechanical switch, or the like.

Further, based on the detection signal according to the voltage change in the ignition circuit, the closing of the switch means may be prohibited until the discriminating means softly passes a predetermined time. As a result, it is possible to prevent the airbag device from operating differently from the design at the moment of mounting the airbag device on the steering wheel. Further, in the conducting means and the contact means, when electrically connecting or contacting the respective components, a fixing member such as a screw or a bolt for installing the respective components may be used. By doing so, it is not necessary to form a special configuration as the conducting means or the contact means, and a simple and inexpensive airbag device can be realized.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an airbag device according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the overall configuration of an airbag device 1 according to the present invention. In FIG. 1, an airbag 20 that inflates in a vehicle collision and protects an occupant is provided with an insertion hole 21 into which the inflator 10 is inserted and a plurality of fixing holes 22 provided around the insertion hole 21. ing. Then, the inflator 1 that generates gas and deploys the airbag 20.
0 is provided with a plurality of gas ejection holes 11 and a flange portion 12 having a plurality of mounting bolts 13. Between the flange portion 12 and the flat surface 41 of the housing 44, the airbag 20 has a nut 70. It is tightened with.

The electronic control unit ECU 40 is provided with a housing 44 having a flat surface 41 and integrally formed, an electronic acceleration sensor for detecting a vehicle collision, and a control circuit for making a collision determination based on a signal from the sensor. ing.
The housing 44 is made of a conductive metal material such as aluminum, and serves as a case for housing the circuit board 39 on which the control circuit, the acceleration sensor, and the like are arranged. The control circuit is provided on the circuit board 39 fixed to the housing 44 with screws (not shown). The structure of the circuit board 39 will be described in detail later with reference to FIG. 2, and has conductivity that is adopted as a fixing member when the circuit board 39 is fixed to the housing 44.
For example, a predetermined part in the control circuit is electrically connected to the case with a screw, a bolt, a screw or the like.

Outer peripheral portion 42 of flat surface 41 of housing 44
Has a bent shape as shown in FIG.
Nut 43 for fixing to the steering wheel 60
Are welded or integrally formed. Further, the sheet metal cover 50 is fixed to the housing 44 by screws 90, and the outer peripheral portion 51 of the cover 50 has a bent shape as shown in FIG. It is configured to cover the outer periphery of the fixed portion 31 of the pad 30. As shown in FIG. 1, the pad 30 is used for the bag 20.
Has a lip line 32 for breaking when expanded.

The airbag device 1 constructed as described above.
Are assembled as described below. That is,
First, the inflator 10 is inserted through the insertion hole 21 on the bottom surface of the airbag 20, and the mounting bolt 13 provided on the flange portion 12 of the inflator 10 is passed through the fixing hole 22 of the airbag 20. At this time, the airbag 20 is folded into a shape that generally matches the internal shape of the pad 30.

Then, the mounting bolt 13 of the inflator 10 is fitted into the fixing hole 45 provided in the flat surface 41 of the housing 44.
The inflator 10 and the electronic control unit ECU 40.
The air bag 20 is clamped and fixed by the nut 70 with the housing 44. Then, the pad 30 is covered so as to cover the folded airbag 20. Then, the fixing portion 31 of the pad 30 is attached to the housing 4
When the pressure is further applied in a state of abutting against the shoulder portion 46 of the flat surface 41 of No. 4, the fixing portion 31 of the pad 30 slides on the outer peripheral portion 42 of the housing 44 while elastically deforming outward, as shown in FIG. In addition, the hook-shaped fixing portion 31 of the pad 30 is fitted into the outer peripheral portion 42 of the housing 44 and fixed. At this time, the pad 30 is assembled in a state in which the reaction force of the folded bag 20 is received and the force acts upward in FIG.

Subsequently, the inflator 10 and the electronic control unit ECU 40 are electrically connected. A hole (not shown) is provided substantially at the center of the flat surface 41 of the housing 44, and the squib (detonation element) terminal formed on the inflator 10 and the circuit board 39 are connected to the inflator 10 by a connector cable or soldering. The electronic control unit 40 is electrically connected.

Finally, the cover 50 of the electronic control unit 40 is put on and fixed to the housing 44 with screws 90.
At this time, since the outer peripheral portion 51 of the cover 50 is bent as shown in FIG. 1, it is fixed so as to cover the outer periphery of the fixing portion 31 of the pad 30. Therefore, in the initial stage of deployment of the airbag 20, the internal pressure until the lip line 32 of the pad 30 breaks is applied to the fixing portion 31 of the pad 30, but the fixing portion 31 does not come off.

In this state, the airbag module component of the airbag device 1 is completed. The airbag device 1 thus configured is mounted on the steering wheel 60 after being electrically connected to the power source on the vehicle body side. That is,
The vehicle body side and the airbag apparatus 1 are electrically connected in advance by using the relay device 4 that electrically connects the rotating steering wheel 60 and the fixed side vehicle body. The relay device 4 is disposed on the steering shaft 61,
The cable 62 extending from the fixed side of the relay device 4 is electrically connected to the vehicle body side. Further, the cable 63 extending from the rotating side that rotates corresponding to the steering shaft 61 is connected to a connector for electrical connection extending from the electronic control unit 40 and the like. After electrically connecting the airbag device 1 side and the vehicle body side in this manner, the bolts 80 are screwed from the outside of the steering wheel 60 to the nut 43 provided on the inner side surface of the outer peripheral portion 42 of the housing 44. Thus, the airbag device 1 is fixed to the steering wheel 60 via a mounting bracket formed of a conductive member (not shown). As will be described later, when the bolt 80 as a conductive fixing member comes into contact with the mounting bracket, the bolt 80 is electrically connected to an ignition circuit that starts ignition of the inflator 10, and receives a small amount of current to receive a predetermined potential. The housing 44, which is set to, is grounded or set to a predetermined potential. That is, the bolt serves as a ground terminal.

As described above, in the airbag device 1 according to the present invention, the inflator 10, the electronic control unit 40, and the airbag 20 are integrated and provided on the steering wheel 60. Such an airbag device 1
A schematic electrical connection configuration and control content of the electronic control unit ECU 40 and the like in FIG. 2 will be described based on FIG.

As shown in FIG. 2, the airbag device 1 is supplied from a battery power source 8 mounted on a vehicle body through a key switch 7, a fuse 6 and the relay device 4 described above.
It is receiving power. A control mechanism for electrically controlling the airbag device 1 is mainly configured on the circuit board 39 as follows. That is, the current from the relay device 4 is supplied to the booster circuit 102 and the backup power source 1
03, the safing sensor 104 and the like are supplied from the input diode 101 which is energized. Acceleration sensor 106
At, the acceleration signal at the time of the vehicle collision is detected, and the collision determination circuit 107 determines the vehicle collision using this acceleration signal. The collision determination circuit 107 also detects an electrical failure of the airbag device 1. When the airbag device 1 fails, the alarm device 3 provided on the pad 30 of the steering wheel 60 is turned on to notify the occupant of the abnormality.

Ignition means are arranged in series in the starting current circuit for supplying the starting current to the squib 2. The ignition means is a switch for energizing and de-energizing the ignition circuit according to a predetermined control signal, and the transistor 15 is adopted here. The transistor 15 is the collision determination circuit 10
When it is determined that the vehicle has collided at 7, and when the energization signal is received from the collision determination circuit 107, the vehicle is energized, and the squib 2 formed in the inflator 10 is supplied with the ignition starting current from the battery power source 8 or the backup power source 103. To do so. In this case, the airbag 20 is supplied with inflation gas from the inflator 10 and inflates to protect the occupant from the impact of a vehicle collision.

A diode 109 is connected downstream of the transistor 105 in parallel with the ignition starting circuit. The extension of the diode 109 is based on the circuit board 39.
Is connected to a fixing portion 81A when fixing the to the housing 44. In the fixing portion 81A, as described above, the housing 44 is secured by the conductive bolts, screws, or the like.
And the circuit board 39 are fixed and at the same time electrically connected. Further, after the housing 44 is energized and the electric potential of the housing 44 is secured in this manner, the electric potential of the housing 44 is set to a predetermined value when the airbag device 1 is mounted on the steering wheel 60, or Bolt 80 as ground terminal 80a so as to be grounded
Is connected to the above-mentioned mounting blanket (not shown). At this time, the housing 44 of the airbag apparatus 1 is fixed to the steering wheel 60 with the bolt 80. That is, the bolt 80 electrically contacts the mounting blanket on the side of the steering wheel 60 and the housing 44 of the airbag device 1.

The terminal a of the signal generating means 108 is connected between the diode 109 and the ground terminal 80a, and the voltage change of the ignition starting circuit due to the grounding of the ground terminal 80a is inputted to the signal generating means 108. The terminal c of the signal generating means is connected to the ground of the ignition starting circuit. The terminal b of the signal generating means is connected to the collision determination circuit 107, and is a detection signal generated by the signal generating means 108, which indicates a voltage change in the downstream side of the diode 109 in the ignition starting circuit and in the housing 44. Is input to the collision determination circuit 107. That is, in the signal generating means, the collision determination circuit 10 is determined according to the behavior of the potential change of the terminal a.
The detection signal is transmitted to 7.

An example of a concrete circuit diagram of the signal generating means 108 is shown in FIG. As shown in FIG. 2, the signal generating means 108 is composed of a predetermined resistor and a transistor 208a. The base of the transistor 108a is connected to the ground terminal 80a. The collector of the transistor 108a is connected to the terminal b connected to the collision determination circuit 107, and the emitter is connected to the terminal c connected to the ground of the ignition starting circuit.

Further, when the air bag device 1 is electrically connected to the battery power source 8 on the vehicle body side by the relay device 4 and the ground terminal 80a is not grounded, a signal indicating this state is output. The signal generation means 108 transmits it to the collision determination circuit 107, and when the collision determination circuit 107 detects this detection signal, the alarm device 3 is configured to light up or blink.

The airbag device 1 configured as described above
The operation of will be described below with reference to FIGS. 4 and 5. FIG. 4 is a flowchart showing the main control of the airbag device according to the present invention. After the airbag device 1 and the battery power source 8 are electrically connected by the relay device 4, the control starts from step 100. In this main routine, the airbag device 1 uses the steering wheel 60.
Even after it is mounted on the vehicle, it operates every time the key switch 7 of the vehicle is turned on. Note that this control is mainly performed by the collision determination circuit 10
7 is executed.

From step 100 to step 130,
This is a normal starting operation in the airbag device 1. That is, in step 100, the warning device 3 is turned on for a predetermined time when steps up to step 130 are completed. Also,
While the alarm device 3 is on, in step 110, the operation of the electronic control circuit including the collision determination circuit 107, the backup power supply 103, etc. is confirmed. Then, in step 120, the stack pointer is initialized, and in step 130, the program work area is initialized.

At step 140, a primary check described later with reference to FIG. 5 is executed. After the primary check is completed, in step 150, the collision determination circuit 107 starts executing the collision determination process. Thereafter, in steps 160 to 180, normal operation such as failure detection in the airbag device is executed. That is, in step 160, the diagnostic control for detecting and diagnosing a failure such as disconnection is always executed while the airbag apparatus 1 is being supplied with current from the battery power source 7 in the future. Further, in step 170, control for turning on and off the alarm device 3 is executed according to the diagnosis result of step 160. Further, in step 180, control is performed to cut off the influence of noise affecting the detection of the acceleration sensor 106 and the like. The control in steps 160 to 180 is executed until the key switch 7 is turned off.

Next, the control contents of the primary check in step 140 will be explained based on the flow chart shown in FIG. When the primary check program starts, in step 200, the alarm device 3 is turned on. In step 210, it is confirmed whether or not the primary check this time is the first operation in which the airbag device 1 is assembled. Here, in a factory or the like, the steering wheel 60
If it is determined that the operation is the first operation when the airbag device 1 is installed in the vehicle, the process proceeds to step 220, and whether or not the correct type of airbag device to be installed in each vehicle is installed. Check for. If it is determined in step 210 that the routine is executed by turning on the normal key switch 7, the process proceeds to step 230.

From step 210 or step 220 to step 230, the ground state of the ground terminal 80a is determined. That is, it is determined whether or not the airbag device 1 is attached to the steering shaft 60 by examining the state of the ground terminal 80a. Here, the operation of the circuit of FIG. 3 described above will be described. As an example, it is assumed that the voltage normally applied to the ignition starting circuit of the airbag device 1 is 5V. When the ground terminal 80a is not brought into contact with the mounting blanket by the bolt 80, the voltage at the terminal a of the signal generating means 108 is 5V.
A current, which is V and is controlled by the predetermined resistance, flows into the beta of transistor 108a. Therefore, in this state, the collector-emitter current flows from the collision determination circuit 107 through the terminals b and c. Therefore, the collision determination circuit receives this current flow as a signal, and it is determined that the ground terminal 80a is not grounded at present and the airbag apparatus 1 is not mounted on the steering wheel 60. In this case, the process proceeds from step 230 to step 260.

When the ground terminal 80a is brought into contact with the mounting blanket by the bolt 80, that is, when the air hauling device 1 is mounted on the steering wheel 60, the ground terminal 80a is grounded and 0
It is V. At this time, since no current flows through the base of the transistor 108a, no collector-emitter current of the transistor 108a also flows. That is, no current flows from the collision determination circuit 107 through the terminals b and c. In this case, the collision determination circuit 107 detects as a signal that no current is flowing, and proceeds to step 250.

When the ground terminal 80a is not grounded in step 230, the process proceeds to step 260. In step 260, the alarm device 3 is blinked in response to the detection signal to let the worker or the like recognize the situation. . Further, here, the collision determination circuit 107 controls the transistor 105 to be in the non-conducting state, and prohibits supply of the starting current to the inflator 2. Here, when the command for prohibiting the supply of the starting current is issued as described above, the next step 2
Even when it is determined that the ground terminal 80a is grounded and the airbag device 1 is mounted at 30, the prohibition state of energization of the transistor 105 is extended for a predetermined time.

When it is confirmed in step 230 that the airbag device 1 is attached to the steering wheel 60 and the process proceeds to step 250, the operation of the memory in the collision determination circuit 107 and the like is normally confirmed. In steps 270 to 320, diagnostic control such as confirmation of normality of power supply from the battery power source 8 or the like is executed. That is, in step 270, it is confirmed whether or not the normal operation is performed in the power supply from the battery power source 8 to the airbag device 1, and the operation is repeated until the normal operation is achieved. If it is determined here that there is no more, step 280, step 2
The routine proceeds to 90, and it is determined whether or not a predetermined time required for the primary check has elapsed after the activation current was supplied to the airbag device 1. Here, the execution of the failure diagnosis is continued in steps 300 and 310 until the predetermined time has elapsed. In step 320, if it is determined in the above-mentioned diagnosis that the airbag device 1 has a failure, the alarm device 3 is turned on, and if it is determined to be normal, the alarm device 3 is turned off. To finish the primary check.

The effects of the airbag device 1 according to the present invention which operates as described above will be described below. As described above, when the airbag device 1 is mounted on the steering wheel 60, the airbag device 1 is connected via the relay device 4.
The side and the vehicle body side are mounted in an electrically connected state. That is, if a worker or the like drops the airbag device 1 and applies an acceleration of a predetermined value or more to the airbag device 1, the acceleration sensor 106 sends a signal similar to that at the time of a vehicle collision to the collision determination circuit 107. Send. At this time, if the collision determination circuit 107 erroneously determines that the vehicle is a collision, the airbag 20 is inflated and deployed. Also,
If a work that causes acceleration is performed when the airbag device 1 is fitted into the steering wheel 60, the airbag 20 inflates and deploys as described above.

However, in the airbag device 1 described above, the ground terminal 80a detects whether or not the airbag device 1 is mounted on the steering wheel 60. Here, since the collision determination circuit 107 prohibits energization of the inflator 2 until the airbag device 1 is mounted on the steering wheel 60 from the mounted state, the accidental explosion as described above occurs. There is nothing to do. In addition, since the activation of the airbag apparatus 1, that is, the energization of the inflator is prohibited for a predetermined time after the airbag apparatus 1 is attached, it is possible to reliably prevent the accidental explosion of the inflator 10 due to the impact during the attachment and the attachment. it can.

Further, it is only the transistor 105 that prohibits the energization of the inflator 2 when the airbag device 1 is not attached, and the mechanical sensor or the like directly deenergizes as in the conventional case. Do not mean. That is, the determination as to whether or not the airbag device 1 is mounted on the steering wheel 60 in the above-described embodiment is performed by a mere terminal that does not require any mechanical element. That is, the voltage change generated at the simple ground terminal 80a is used as a detection signal by the signal generating means 108 having a simple structure including the transistor 108a and a predetermined resistor, and the energization of the inflator 2 is electrically prohibited according to the detection signal. ing. Therefore, it is possible to apply the airbag device 1 capable of accurately preventing erroneous explosion with a very simple configuration. Further, a high-performance and expensive switch or sensor for detecting the mounting of the airbag device 1 is not required, and the cost of the airbag device 1 can be reduced with a very simple structure.

Further, when the airbag device 1 is not attached to the steering wheel 60, that is, while the transistor 105 is in the non-energized state, the alarm device 1 is provided.
By blinking, the operator can be made aware of the operating state of the airbag apparatus 1, and the safety in the work of mounting the airbag apparatus 1 can be ensured.

As described above, in the airbag device 1 according to the present invention, the steering wheel 6 of the airbag device 1 is used.
The non-wearing state to 0 and the wearing status are detected by a simple switch connected in parallel with the ignition starting circuit of the squib 2, and the operation of the airbag apparatus 1 is electrically prohibited according to the result. Therefore, it is possible to accurately prevent the malfunction of the airbag device 1 with a simple and inexpensive structure.

The present invention is not limited to the above embodiment, but can be variously modified as follows. For example, although an electronic acceleration sensor is adopted as the acceleration sensor 106 in the above embodiment, the same effect as that of the above embodiment can be obtained by using a mechanical acceleration sensor or an acceleration switch.

In the above embodiment, the transistor is used to form the monitor circuit. However, the present invention is not limited to this. For example, even if a comparator or the like is used, the same essential points as in the above embodiment are obtained. Obtainable.

[0049]

As described above in detail, according to the airbag device of the present invention, an airbag device capable of accurately preventing a malfunction with a simple structure at the time of attachment / detachment to / from a vehicle is provided. Can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a configuration when an airbag device according to the present invention is attached to a steering wheel of a vehicle.

FIG. 2 is a circuit diagram showing a control mechanism of the airbag device according to the present invention.

FIG. 3 is a circuit diagram showing a signal generating means.

FIG. 4 is a flowchart showing a main routine of the airbag device according to the present invention.

FIG. 5 is a flowchart showing a primary check routine of the airbag device according to the present invention.

[Brief description of reference numerals]

 1 Airbag device 2 Squib 3 Alarm device 4 Relay device 8 Battery power supply 10 Inflator 20 Airbag 39 Circuit board 40 Electronic control unit ECU 44 Housing 60 Steering wheel 80 Volt 80a Ground terminal 105 Transistor 106 Acceleration sensor 107 Collision determination circuit 108 Steering Attachment detection switch 108a Transistor 109 Diode 110 Resistance

Claims (15)

[Claims] 1. An airbag, an inflator for supplying high-pressure gas to the airbag, and an ignition circuit for activating the inflator when a predetermined ignition power source is energized. The ignition circuit is provided in a case having conductivity. A vehicle airbag device housed and integrally mounted on a steering wheel, comprising switch means connected in series to the ignition circuit and capable of switching between an open state and a closed state by a control signal, Conduction means for conducting the case and the downstream of the switch means; contact means for electrically contacting the steering wheel and the case by mounting the airbag device on the steering wheel; The electrical contact between the steering wheel and the case is detected as a change in voltage in the case. However, the vehicle air is provided with a signal generating means for generating a detection signal, and a prohibiting means for prohibiting the switch means from being in a closed state until the detection signal is received from the signal generating means. Bag device. 2. The steering wheel is a ground, and the potential of the case drops to a predetermined value by the contact of the case with the steering wheel, and the signal generating means detects a change in this voltage. The airbag device according to claim 1. 3. The steering wheel is electrically connected to a predetermined power source, and when the case contacts the steering wheel, the potential in the case rises by a predetermined value, and a change in this voltage is generated by the signal generation. The air bag device according to claim 1, wherein the air bag device is detected by means. 4. The deceleration detecting means for detecting deceleration acceleration of the vehicle by the vehicle airbag device integrally mounted on the steering wheel, and outputting a signal according to the deceleration acceleration, Based on the deceleration signal from the detecting means, a determining means for determining whether or not the vehicle is in a collision state, and when the determining means determines that the vehicle is in a collision state, the switch means is turned on. The air bag device according to claim 2 or 3, wherein the ignition current is supplied. 5. The detection signal detected and output by the signal generating means is input to the discrimination means, and when the discrimination means detects the input of the detection signal, the operation of the switch means is permitted. The airbag device according to claim 4, wherein: 6. A deceleration switch, which is mechanically responsive to a deceleration caused by the collision to close the contacts when the vehicle collides, is connected in series to the ignition circuit.
The airbag device according to claim 5. 7. A timer means for prohibiting the switch means from being in an open state until a predetermined time elapses after the detection signal is detected by the determination means, the timer means being provided. The airbag device according to claim 6. 8. The predetermined warning light is lit or blinked while the prohibiting means prohibits the switch means from being in an open state, and displays the light.
The airbag device according to claim 7. 9. The display means for turning on or off a predetermined warning light when the timer means prohibits the switch means from being opened for a predetermined time. 7. The airbag device according to 7. 10. The airbag device according to claim 1, wherein the switch means is formed of a transistor connected in series to the ignition circuit. 11. The switch means is closed to apply an ignition current to the inflator in order to deploy an airbag for protecting an occupant when the determination means determines that the vehicle is in a collision. The airbag device according to any one of claims 1 to 10, which is characterized. 12. The transistor according to claim 1, wherein a base current of a transistor electrically connected to the case is grounded in response to mounting the airbag device on a steering wheel of the transistor. 12. The airbag apparatus according to claim 4, wherein at least one of the emitter current and the collector current of the device is changed, and the change is transmitted to the discriminating means as the detection signal. 13. The conducting means includes a conducting portion extending from a downstream side of the switch means in the ignition circuit, in a screw tightening portion for installing the substrate in the case, in the substrate on which the ignition circuit is configured. 13. The fixing member electrically connects the conducting portion and the case when the substrate is installed in the case with the fixing member having electrical conductivity. The airbag device according to any one of 1. 14. The contact means, when the case is installed by a fixing member having conductivity, to the mounting bracket having conductivity for mounting the case to the steering wheel, the fixing member is The airbag device according to any one of claims 1 to 13, wherein the case and the bracket are in electrical contact with each other. 15. The prohibiting means unconditionally opens the switch means until a detection signal indicating that the airbag device is mounted on the steering wheel is input from the signal generating means to the determining means. 15. The closing of the switch means is prohibited by a signal from the discriminating means for a predetermined time after the detection signal is input to the discriminating means. The airbag device according to any one of 1.