JPH07112800B2 - Malfunction prevention device for air bag modules in automobiles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Purpose of the Invention (1) Field of Industrial Application The present invention is intended to prevent a driver from contacting a steering wheel, a windshield, etc. by rapidly inflating an airbag when a vehicle collision accident occurs. The present invention relates to a device for preventing malfunction of an airbag module that is designed to prevent the malfunction.

(2) Conventional Technology An airbag, an inflator capable of rapidly supplying high-pressure gas to the bag, a deceleration sensing mechanism for operating the inflator when the vehicle body deceleration rises above a certain value, and the like. In an automobile in which an airbag module can be attached to and detached from a steering wheel, in order to prevent malfunction of the module when the module is detached from the steering wheel, for example, as shown in JP-A-53-78536, It is well known in the art that a lock mechanism that engages with the deceleration sensing mechanism and disables the deceleration sensing mechanism is operated in the disengaged state of the airbag module.

(3) Problems to be Solved by the Invention In the above-mentioned conventional structure, in order to prevent malfunction of the airbag module, the exclusive locking mechanism that is interlocked with the attachment / detachment operation of the module is required to have high accuracy. Since it is necessary to specially add to the complicated deceleration sensing mechanism, the structure is complicated and the cost is increased as a whole, and the operation accuracy of the deceleration sensing mechanism may be deteriorated.

The present invention has been proposed in view of the above, and an object thereof is to provide a malfunction preventing device for an airbag module having a simple structure, which can solve the problems of the conventional device.

B. Configuration of the Invention (1) Means for Solving the Problems In order to achieve the above object, the present invention provides an airbag and an inflator capable of rapidly supplying high-pressure gas to the airbag in order to rapidly inflate the airbag. An operating circuit that is detachably connected to the main power supply circuit provided on the vehicle body side and that can operate the inflator by the power supplied from the main power supply circuit; and an operating circuit that is interposed in the operating circuit and opens during normal operation to reduce the vehicle body. A vehicle in which a steering wheel is detachably mounted with an airbag module including a deceleration sensing switch that closes when the speed exceeds a predetermined value, and an auxiliary power supply circuit that is connected to the actuation circuit in parallel with the main power supply circuit. In, a drive gate interposed in the actuation circuit and closed in normal times,
In order to open the drive gate when the airbag module is disengaged from the steering wheel, a control device that can apply a signal voltage from the auxiliary power supply circuit to the gate in the disengaged state is provided.

(2) Operation According to the above configuration, when the airbag module is removed from the steering wheel, the drive gate receives a signal voltage from the auxiliary power supply circuit to open the operating circuit of the inflator, and the open state continues. Since the electric potential of the auxiliary power supply circuit drops below the functional level of the operating circuit, there is no fear that the inflator will malfunction even if the deceleration sensing switch operates due to an impact.

(3) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIGS.
Is a central boss plate 1, an annular wheel rim 2 that serves as a grip, the wheel rim 2 and the boss plate 1.
In order to integrally connect the left and right sides of the boss plate 1, two spokes 3 to the left and right, which extend radially from the left and right side portions of the boss plate 1, are spaced apart from each other in the circumferential direction, and the spokes 3 and the boss plate 1 are covered. The boss plate 1 is composed of the front and rear halves of the wheel cover 4 fixed to cover them.
Is connected to the rear end of a steering shaft 6 rotatably supported on the steering column 5.

An arm-shaped module case 7 of the airbag module M is attached to the boss plate 1 as follows. That is, the left and right ends of the boss plate 1 are bent toward the steering column 5, and a pair of left and right brackets 7a fixed to the bottom surface of the module case 7 are in contact with the bent ends 1a. A bolt B penetrating the bracket 7a is screwed, and the bracket 7a is fixed to the boss plate 1 via the bolt B. Wheel cover 4
A pair of light-transmitting members 4a through which a tool (not shown) for tightening the bolt B is inserted are provided in the hole, and the module case 7 is further provided.
An opening 4b is formed to surround the outer peripheral portion of the with a small gap.

The airbag module M is connected to an inflator I for rapidly supplying high-pressure gas to the airbag A and a main power supply circuit Em provided on the vehicle body side, and is supplied with electric power from the main power supply circuit Em. An operating circuit C capable of operating the ignition device 8, a deceleration sensing switch S interposed in the operating circuit C, opened during normal times, and closed when deceleration of a vehicle body exceeds a certain value, and the operating circuit C. And an auxiliary power supply circuit Es connected in parallel with the main power supply circuit Em, which are housed and held inside the module case 7. A bowl-shaped module cover 9 is attached to an opening edge portion of the module case, and a tip portion of an airbag A having a base portion fixed to an outer peripheral portion of the inflator I is folded in a space covered by the cover 9. It is housed in a room.

An on-vehicle battery Ba and an ignition switch Ig of an engine (not shown) are provided in series in the main power supply circuit Em, but the switch Ig can be omitted from the main power supply circuit Em. The auxiliary power supply circuit Es is provided with a capacitor 10 as an auxiliary power supply, and a resistor R through which a current flows when the capacitor 10 is charged and a diode D through which a current flows when the capacitor 10 is discharged are parallel to each other. It is provided.

The connection cord 11 for connecting the actuation circuit C and the main power supply circuit Em is provided with a coupler 12 for separating the airbag module M side portion and the steering wheel W side portion of the cord 11 from each other, and thereafter. A publicly known slip ring 13 which allows relative rotation between the steering wheel W and the steering column 5 is interposed in the person's part.

Further, the airbag module M is provided with a malfunction prevention device 14 for preventing malfunction of the module M when it is removed from the steering wheel W. This device 14 includes a drive gate G which is interposed in an operating circuit C between the deceleration sensing switch S and the ignition device 8 of the inflator I and is closed in an inactive state, and an auxiliary power supply circuit Es connected to the gate G. A control device 15 capable of applying a signal voltage is provided, and the drive gate G is operated and opened only when the signal voltage is higher than a predetermined level, that is, a voltage level at which the operating circuit C can be effectively operated. Composed. The control device 15 is opened when the signal circuit 16 that connects between the auxiliary power supply circuit Es and the signal input portion of the drive gate G and the module M that is interposed in the circuit 16 is mounted on the steering wheel W of the module M. Further, it is composed of an attachment / detachment detection switch Sw that closes when it is detached. The switch Sw is, for example, attached to the bottom wall of the module case 7 and the adjustment screw 17 on the boss plate 1 side when the module M is mounted.
A normally-closed type micro switch in which the actuator 18 is pressed against is used.

Next, the operation of the above-described embodiment will be described. In the airbag module M, the bracket 7a on the bottom surface of the module case 7 is attached via the bolt B to the bracket of the boss plate 1 when the airbag module M is attached to the steering wheel W.
Since the attachment / detachment detection switch Sw is fixed in the open state by the engagement of the actuator 18 and the adjusting screw 17 on the boss plate 1 side in this state, the drive gate G has each power circuit Em, No signal voltage is applied from Es, and therefore the gate G is electrically connected between the deceleration sensing switch S and the ignition device 8. In addition, since the deceleration acting on the vehicle body is below a certain value in a normal driving state of the automobile, the deceleration sensing switch S does not operate and is held in the open state, so that the actuation circuit C eventually detects the deceleration sensing. It is open only by the switch S.

Therefore, in such a situation, when the vehicle suffers a collision accident and deceleration of a certain amount or more acts on the vehicle body, the deceleration sensing switch S is immediately actuated to close the operation circuit C, and the main power circuit Em causes the inflator I to move. Since the ignition device 8 is energized, the ignition device 8 ignites the object to be ignited in the inflator I and the high pressure gas is rapidly supplied from the inflator I into the airbag A. It expands and breaks through the module cover 9 and closes to the front of the driver greatly, so that the driver's collision with the steering wheel W, the windshield (not shown) and the like can be prevented. Moreover, even if the main power circuit Em cannot be energized to the operating circuit C due to disconnection or the like at the time of the collision accident,
Power is supplied from the auxiliary power supply circuit Es to the operating circuit C, so that the operation of the inflator I is not hindered.

By the way, when removing the inactive airbag module M from the steering wheel W, after loosening the bolts B and pulling them out to the outside through the light transmission 4a of the wheel cover 4, the module case 7 is held in the hand. It suffices to pull the steering wheel W backward along the axis of the steering wheel W and disconnect the coupler 12 of the connection cord 11. Module M above
According to the removal work of (1), the attachment / detachment detection switch Sw is automatically closed, and the signal voltage is applied to the drive gate G from the auxiliary power supply circuit Es. Since it is higher than the functional level, the gate G is opened, and as a result, even if the deceleration sensing switch S is actuated and closed due to an impact or the like, the actuation circuit C is not likely to be closed, and the inflator I does not have to be closed. Malfunctions can be reliably prevented. Further, as described above, when the discharge amount of the capacitor 10 increases with the application of the signal voltage from the auxiliary power supply circuit Es to the drive gate G and the potential thereof drops below the functional level of the predetermined belt, that is, the operating circuit C, the drive gate G Returns to the closed state, but after that, the deceleration sensing switch S
However, if the auxiliary power supply circuit Es is closed due to an erroneous operation, the potential of the auxiliary power circuit Es is below the function level of the operating circuit C, so that there is no risk of the inflator I malfunctioning.

C. Effects of the Invention As described above, according to the present invention, the air bag, the inflator capable of rapidly supplying high-pressure gas to the air bag to rapidly inflate the air bag, and the main power circuit arranged on the vehicle body side can be detachably attached. An operating circuit that is connected to the vehicle and can operate the inflator by the power supplied from the main power supply circuit, and a deceleration sensing switch that is interposed in the operating circuit and opens during normal times and closes when the deceleration of the vehicle body exceeds a predetermined value. And an auxiliary power circuit connected to the actuation circuit in parallel with the main power circuit, an airbag module is detachably attached to a steering wheel, and in the normal operation, the airbag module is interposed in the actuation circuit. In order to open the drive gate that can be closed and this drive gate when the airbag module is detached from the steering wheel, the same drive gate is used in the detached state. And a control device capable of applying a signal voltage from the auxiliary power supply circuit to the drive gate, when the airbag module is removed from the steering wheel, the drive gate receives the signal voltage from the auxiliary power supply circuit and automatically operates the inflator operation circuit. If the open state continues, the potential of the auxiliary power supply circuit can be lowered below the functional level of the operating circuit.Therefore, even if the deceleration sensing switch malfunctions due to impact, the inflator will malfunction. There is no fear of working. In addition, since the deceleration sensing switch, which requires high precision and has a complicated structure, does not require any special work or modification, the structure is simple as a whole, and the operating accuracy of the deceleration sensing switch may be reduced. There is no.

[Brief description of drawings]

The drawings show an embodiment of the present invention. FIG. 1 is an overall view in which a steering wheel portion is longitudinally cut, and FIG. 2 is a circuit diagram. A ... Airbag, C ... Operating circuit, Em ... Main power circuit, Es ... Auxiliary power circuit, G ... Drive gate, I ...
… Inflator, M …… Airbag module, S ……
Deceleration detection switch, W …… Steering wheel 15 …… Control device

Claims (1)

[Claims] 1. An air bag, and an inflator capable of rapidly supplying high-pressure gas to the air bag in order to rapidly inflate the air bag.
An actuation circuit that is detachably connected to the main power supply circuit arranged on the vehicle body side and that can operate the inflator by the power supplied from the main power supply circuit; and a deceleration of the vehicle body that is interposed in the operation circuit and opens during normal times. In a vehicle in which a steering wheel is detachably mounted with an airbag module that includes a deceleration sensing switch that closes when exceeds a predetermined value, and an auxiliary power supply circuit that is connected to the actuation circuit in parallel with the main power supply circuit. , A drive gate which is interposed in the operating circuit and which is closed in normal times, and a signal voltage from the auxiliary power supply circuit to the gate in the detached state so that the drive gate is opened in the detached state from the steering wheel of the airbag module. A device for preventing malfunction of an airbag module in an automobile, characterized by comprising: .