JP2001080452A - Occupant crash protection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ignite in a multi-step surely by having hold means for holding the connection state of the contact point of a safing sensor by an electric power supply and interposing the contact point of the safing sensor between the power source and hold means. SOLUTION: As a gunpowder placed on a squib 5S is gasified by the heating of the squib 5S by the electric power supplied from an air bag ignition power source VDC to A point though a first safing sensor contact point 41, the first step expansion of the air bag is carried out. When an ignition signal is outputted to switching elements for ignition 3S, 4S, a circuit including the switching elements for ignition 3S, 4S, squib 5S and current detector 6S is conducted from A point to an earth line. As the gunpowder placed on the squib 5S is gasified by the heating of the squib 5S by the electric power supplied from the air bag ignition power source VDC to A point through the first safing sensor contact point 41, the second step expansion of the air bag is carried out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupant protection device provided as a safety device for a vehicle, and more particularly, to a starting circuit such as an airbag for ensuring a multi-stage ignition operation.

[0002]

2. Description of the Related Art When a microcomputer (microcomputer) processes signals from a G sensor (acceleration sensor) or the like and determines that a collision has occurred, an ignition current is output to a squib (ignition heater) to activate an inflator for inflating an airbag. An airbag activation circuit for generating (explosive gas is heated by a squib when an explosive of an inflator is heated) will be described below with reference to FIG.

FIG. 8 shows a conventional airbag starting circuit disclosed in Japanese Patent Application Laid-Open No. 9-39727. In the airbag activation circuit, the microcomputer 36 controls the current from the power supply VDC to the ignition heater based on the acceleration from the safing sensor contact 1 which is a mechanical acceleration detection contact and the G sensor 31 (acceleration sensor). When each of the switches 3 and 4 is connected, energization to the squib 5 (= ignition heater) is widely performed. This is because, when the ignition process is performed only by the signal processing by the microcomputer (judging the collision from the acceleration signal from the G sensor 31), the signal processing malfunctions in rare cases due to external electromagnetic noise or the like, and the ignition signal is output. In order to avoid such concerns, the ignition process is performed under the condition that the connection of the mechanical type safing sensor contact portion 1 by the collision acceleration in addition to the semiconductor switches 3 and 4 is performed at the same time, and the fail-safe operation of the airbag due to malfunction is achieved. is there.

In the air bag activation circuit shown in FIG. 8, a structure for stabilizing the contact connection operation of the mechanical type safing sensor contact portion 1 is employed. The microcomputer 36 detects the voltage at the point A, and outputs a signal from the point B to the semiconductor switch 22 to turn on the semiconductor switch 22.
Is conducted to the electromagnetic coil 11. Electromagnetic coil 1
1 generates a magnetic force to forcibly connect the connection of the safing sensor contact 1 for a predetermined time.

This is a process for coping with a phenomenon in which the acceleration applied to the mechanical type safing sensor contact portion 1 hunts at the time of a vehicle collision. When the acceleration hunts, the safing sensor contact portion 1 may be connected once immediately after the collision, and may be momentarily disconnected immediately after the collision.
Since the ignition current does not flow even if an ignition signal is applied to the squib 4, there is a risk that the squib 5 will generate insufficient ignition heat and will not ignite. Therefore, once the connection of the safing sensor contact portion 1 is detected immediately after the collision, the ignition signal output period (for example, 50 ms from when the safing sensor contact portion 1 is turned on (connected) to when the ignition signal output is scheduled to end), Microcomputer 36
A signal is output from the connection point B to supply a current to the electromagnetic coil 11 for a predetermined period of time, and even in a situation where hunting occurs in the acceleration, the once connected safing sensor contact 1
Is forcibly maintained.

Next, the safing sensor 1 shown in FIG.
0 will be described with reference to FIG. The safing sensor contact portion 1 is a reed switch having leads 91 and 92 using a magnetic metal wire housed in a glass tube, and the contact portion 93 of the leads 91 and 92 is normally disconnected and connected in a magnetic field. It is configured so that Further, the safing sensor contact portion 1 is housed in a cylindrical non-magnetic metal container having an outer wall 98 and an inner wall 97. Outside the inner wall 97, a cylindrical permanent magnet 95 movably held.
And a spring 96 that opposes the permanent magnet 95 in the acceleration direction. With this configuration, the position of the permanent magnet 95 moves in accordance with the acceleration, and when the acceleration exceeds a predetermined threshold, the permanent magnet 95 is opposed to the position of the contact point 93, and the magnetic flux lines from the permanent magnet 95 are transmitted from the leads 91. After passing through the lead 92, the contact 93 is in a connected state. An electromagnetic coil 11 is wound around the outer periphery of the outer wall 98. Electromagnetic coil 1
When a current is supplied, 1 generates a magnetic force, and the generated magnetic flux lines pass from the lead 91 to the lead 92, and the contact 93 is connected.

Although the above-described safing sensor having the configuration in which the electromagnetic coil 11 is not mounted has been widely used in the past, according to the configuration of FIG. 8, when the connection of the safing sensor contact portion 1 is detected. Since the current is supplied to the electromagnetic coil 11 for a predetermined time, even if the hunting occurs in the acceleration and the permanent magnet 95 moves away from the position of the contact 93, the safing sensor contact portion once connected by the magnetic force from the electromagnetic coil 11 1 can be reliably maintained during the ignition period.

[0008]

By the way, in the conventional airbag starting circuit, the connection of the safing sensor contact portion 1 is performed during a period in which the acceleration immediately after the collision exceeds the threshold and is large, that is, a period during which the microcomputer 36 outputs the ignition signal. (From the ON (connection) of the safing sensor contact 1 to the scheduled end of the output of the ignition signal, for example, for 20 ms). In recent multi-stage inflatable airbags for passenger airbags, etc., a plurality of squibs are configured to sequentially energize and ignite a plurality of explosives with a time lag, and the time of deployment of the final stage (that is, the final stage) Since the ignition signal output time) may exceed the normal connection time of the safing sensor contact portion 1 (a time period in which the acceleration exceeds the threshold value and is large), the safing sensor may have a predetermined time as described with reference to FIG. It is necessary to continue the process of forcibly turning on (connecting) the contact portion 1 for a long time (for example, for about 200 ms).

In the case of performing the signal processing as shown in FIG. 8, there is a concern that the signal processing of the microcomputer 36 or the like may cause a malfunction due to extraneous electromagnetic noise or the like. Regardless of the presence or absence of the mechanical shock acceleration to the sensor 10, the current is continuously supplied to the electromagnetic coil 11, and the safing sensor contact portion 1 is continuously turned on (connected). Under such circumstances, when an ignition signal is output due to a malfunction of signal processing of a microcomputer or the like in parallel, there is a concern that the deployment of the airbag becomes inappropriate.

The present invention solves such a problem. Even if a malfunction occurs due to electromagnetic noise or the like in signal processing of a microcomputer or the like, the development of an airbag or the like can be appropriately performed without depending on the malfunction. Another object of the present invention is to reliably hold the contacts of the safing sensor even in a multi-stage deployment.

[0011]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and comprises a safing sensor whose contacts are connected according to the acceleration of a vehicle, occupant protection means for protecting an occupant of the vehicle, and explosive. A squib that ignites the squib, and when the contact point of the safing sensor is in a connected state, the squib is energized to activate the occupant protection means. Holding means for holding the connection state of the contacts of the safing sensor, wherein the contacts of the safing sensor are interposed between the power supply and the holding means.

The vehicle further includes a safing sensor whose contacts are connected according to the acceleration of the vehicle, occupant protection means for protecting an occupant of the vehicle, and a squib for igniting explosive,
When the contacts of the safing sensor are connected, the squib is energized, and in the occupant protection device that activates the occupant protection means, the power supply and the power supply from the power supply change the connection state of the contacts of the safing sensor. Holding means for holding, and first switching means that is connected when the squib is energized, wherein a contact point of the safing sensor and the first switching means are provided between the power supply and the holding means. Is interposed.

[0013] The vehicle further includes a safing sensor whose contacts are connected according to the acceleration of the vehicle, occupant protection means for protecting occupants of the vehicle, and a squib for igniting explosive,
When the contacts of the safing sensor are connected, the squib is energized, and in the occupant protection device that activates the occupant protection means, the power supply and the power supply from the power supply change the connection state of the contacts of the safing sensor. Holding means for holding, and second switching means to be in a connected state when a collision is determined based on the acceleration,
A contact point of the safing sensor and a second switching unit are interposed between the power supply and the holding unit.

Further, the safing sensor includes two contacts interlocked with each other, and the holding means generates an electromagnetic force for maintaining a connection state of the two contacts of the safing sensor by supplying power from the power supply. A coil, wherein one of the safing sensors is connected to the squib, and the other contact is connected between the electromagnetic coil and the power supply.

Further, the power supply includes a capacitor, and the holding time of the holding means is defined by discharging the capacitor.

Further, the squib is provided in a plurality of stages, and the holding time of the holding means includes a timing from a current supply timing to the first stage squib to a current supply timing to the last stage squib.

[0017]

Next, the structure of a safing sensor according to an embodiment of the present invention will be described with reference to FIG.

FIG. 1 is a structural diagram illustrating the structure of a safing sensor 40 according to an embodiment of the present invention.

Reference numerals 41 and 42 denote first and second safing sensor contact portions each composed of a reed switch. The contacts 413 and 423 of the reed enclosed in a glass tube are normally in a non-connected state, but under a magnetic field. It is configured to be connected. In addition, the first and second safing sensor contacts 4
Reference numerals 1 and 42 are housed in a cylindrical non-magnetic metal container having an outer wall 48 and an inner wall 47. On the outside of the inner wall 47,
A cylindrical permanent magnet 45 movably held and a spring 46 that opposes the permanent magnet 45 in the acceleration direction are housed therein. The permanent magnet 45 compresses the spring 46 according to the acceleration,
The position of the permanent magnet 45 moves. Thus, when the acceleration exceeds the predetermined threshold, the permanent magnet 45 is opposed to the positions of the contacts 413 and 423, and the magnetic flux lines from the permanent magnet 45 are transferred from the leads 411 (and 421) to the leads 41.
2 (and 422) and contacts 413 (and 42).
3) is in a connected state. An electromagnetic coil 43 is wound around the outer periphery of the outer wall 48. The electromagnetic coil 43 generates a magnetic force when a current is supplied, and the generated magnetic flux lines
1 (and 421) to lead 412 (and 422)
And the contacts 413 (and 423) are connected. The contact 413 (and 423) is connected when at least one of a magnetic flux line from the permanent magnet 45 and a magnetic flux line from the electromagnetic coil 43 acts.

Next, an airbag starting circuit according to the first embodiment of the present invention will be described with reference to FIG.

FIG. 2 is a configuration diagram showing the configuration of the airbag starting circuit according to the first embodiment of the present invention.

Reference numeral 40 denotes a safing sensor whose structure has been described with reference to FIG. 41 is an airbag ignition power supply V
This is a first safing sensor contact portion that switches the connection from DC (for example, composed of a DC-DC converter or the like) to point A to a disconnected or connected state. The first safing sensor contact part 41 is normally in a non-connected state, and is connected when the acceleration applied to the safing sensor 40 exceeds a predetermined threshold value or when the current Im is supplied to the electromagnetic coil 43. You. Reference numeral 42 denotes a second safing sensor contact that switches the connection from the point C of the current supply unit 50 to the electromagnetic coil 43 to a non-connection or connection state. The second safing sensor contact portion 42 is normally in a disconnected state, and is connected when the acceleration applied to the safing sensor 40 exceeds a predetermined threshold or when the current Im is supplied to the electromagnetic coil 43. You. Reference numeral 43 denotes an electromagnetic coil for connecting the first and second safing sensor contact portions 41 and 42 with an electromagnetic force. Reference numeral 50 denotes a current supply unit that supplies a current Im to the electromagnetic coil 43. The current supply unit 50 includes a resistor 51 connected to a control power supply VCC supplied from a battery, and a safing sensor 4.
And a large-capacity capacitor 52 that is a holding power source for an electromagnetic force of zero. In the current supply unit 50, the electric charge normally input from the power supply VCC via the resistor 51 is stored in the capacitor 52, and when the second safing sensor contact unit 42 is mechanically connected by receiving the acceleration, from the point C The conduction to the ground side is conducted via the electromagnetic coil 43, and the electric charge stored in the capacitor 52 is discharged. That is, when the second safing sensor contact portion 42 is connected under the action of acceleration, the supply of the current Im, which is the magnetizing current of the electromagnetic coil 43, is started. When the supply of the current Im is started, an electromagnetic force is generated from the electromagnetic coil 43 according to the current Im, and the first and second safing sensor contact portions 41 and 42 are generated.
Is connected. Further, as the discharge proceeds, the current Im decreases and the electromagnetic force generated by the electromagnetic coil 43 weakens, so that the first and second safing sensor contact portions 41, 42 are provided.
Cannot be secured, and the connection of the first and second safing sensor contact portions 41 and 42 is released and disconnected. Then, when the current Im falls below the lower limit for the electromagnetic connection, the connection of the second safing sensor contact portion 42 is disconnected, and the discharge from the capacitor 52 is stopped. The current Im is a first current which is a main current from the electric charge stored in the capacitor 52, and a resistance in which the resistance 51 is set to a large resistance value so that the current value is considerably smaller than the first current. 51 and a second current flowing directly from the power supply VCC. That is, the first and second safing sensor contact portions 41 and 42
Is connected when the first current, which is the main magnetizing current, is at a high level, and is disconnected when the second current remains but the first current decreases. On the other hand, the electromagnetic coil 4
The value of the reactance 3 and the capacitance of the capacitor 52 are determined by selecting a time constant so that the high level of the current Im for maintaining the above-mentioned connection state can be maintained until the ignition timing of the last stage of the airbag. Since the circuit is configured in this manner, the electromagnetic coil 43 is energized during the period in which the second safing sensor contact portion 42 is in the connected state, and the first and second sensors are energized.
The safing sensor contact portions 41 and 42 are connected, and when the magnetizing current value is weakened, there is no electromagnetic force to be connected, so that the second safing sensor contact portion 42 is disconnected and the first The safing sensor contact portion 41 is also in a non-connected state.

2 is an ignition switching element 3, 3S,
This resistance is inserted in parallel with the first safing sensor contact portion 41 in order to supply a very small current that does not cause the squib 5 to ignite during the 4,4S test.

Reference numerals 3, 3S, 4, and 4S denote ignition switching elements. When the microcomputer 30 finally determines a collision based on a signal from the G sensor (semiconductor acceleration sensor) 31 and outputs an ignition signal, the microcomputer 30 is turned on. . Reference numerals 5, 5S denote squibs which ignite the explosive for inflating the airbag, and are composed of resistors which generate heat when energized. 6,6S is
The microcomputer 30 is a current detector for monitoring an ignition current at the time of a continuity test or outputting an ignition signal, and outputs, for example, an L (low) signal when the ignition current is supplied. The ignition switching elements 3 and 4, the squib 5, the current detector 6
Is related to the squib 5 opposed to the explosive that performs the first-stage inflation operation of the airbag. Also,
The circuit including the switching elements for ignition 3S, 4S, the squib 5S, and the current detector 6S relates to the squib 5S opposed to the explosive for performing the second-stage inflation operation of the airbag.

Reference numeral 30 denotes a microcomputer (microcomputer) which constantly monitors the activation circuit of the airbag, determines the collision, and operates the activation circuit. The microcomputer 30 has an arithmetic function, a storage function, and the like. When the microcomputer 30 determines a collision based on a signal from the G sensor 31, the microcomputer 30 outputs an ignition signal. The ignition signal is first output to the ignition switching elements 3 and 4 related to the first-stage inflation operation of the airbag (for example, 20 m).
s). Next, a predetermined delay period (for example, 100 ms)
Then, an ignition signal is output (for example, 20 ms) to the ignition switching elements 3S and 4S.

As described above, when the ignition signal is output to the semiconductor switching elements 3 and 4 for ignition, a circuit including the switching elements 3 and 4 for ignition, the squib 5 and the current detector 6 is connected from the point A to the ground line. To the air bag ignition power supply VD via the first safing sensor contact 41.
The electric power supplied from the point C to the point A heats the squib 5 and gasifies the explosive opposed to the squib 5, so that the first stage (first stage) of the airbag is inflated. When the ignition signal is output to the ignition switching elements 3S, 4S, the ignition switching elements 3S, 4S, the squib 5
S, the circuit including the current detector 6S conducts from the point A to the ground line, and the power supplied from the airbag ignition power supply VDC to the point A via the first safing sensor contact portion 41 passes through the squib 5S. Since heating is performed to gasify the explosive opposed to the squib 5S, the second stage (final stage) of the airbag is inflated.

FIG. 3 is a timing chart showing the timing according to the first embodiment of the present invention.

FIG. 3A shows the timing at which a collision G value (acceleration value) output from the G sensor 31 is generated. When a vehicle collision occurs, the signal indicating the collision G value is α
Are output from the G sensor 31 during the period indicated by.

FIG. 3B shows the connection timing of the first and second safing sensor contact portions 41 and 42. During the period when the collision G value exceeds the predetermined threshold, the movable permanent magnet 45 receives the acceleration and compresses the spring 46, and the permanent magnet 45 is opposed to the contact points 413 and 423.
Corresponding to the period indicated by α, as shown by the dotted line,
The second safing sensor contacts 41 and 42 (contact 41
3, 423) is in a connected state. On the other hand, once the second safing sensor contact portion 42 is in the connected state in this way, the electromagnetic coil 43 is energized from the point C of the current supply portion 50, so that the electromagnetic coil 43 generates a magnetic force (electromagnetic force). , First and second safing sensor contact portions 41 and 42
(Contacts 413 and 423) are continuously connected. The connection state according to the generation of the magnetic force is, as shown in the connection state indicated by the solid line, the lower limit at which the current Im from the capacitor 52 can connect the first and second safing sensor contact portions 41 and 42 by the electromagnetic force. Retained for a period greater than the value. That is,
Even if the acceleration decreases and the magnetic force from the permanent magnet 45 disappears and the first and second safing sensor contact portions 41 and 42 return to the disconnected state, the magnetic force (electromagnetic force) by the electromagnetic coil 43 continues. Therefore, the connection state is maintained while the magnetizing current discharged from the capacitor 52 is at a sufficient level.

FIG. 3C shows the current Im of the current supply unit 50.
3 shows the output timing. Once the second safing sensor contact portion 42 is brought into the connected state by acceleration, the output of the current Im from the current supply portion 50 is started, and the discharge of the electric charge from the capacitor 52 continues, but the current Im decreases and the current Im decreases. 1. When the lower limit value of the current Im that generates the electromagnetic force capable of connecting the second safing sensor contact portions 41 and 42 is reached, the second safing sensor contact portion 42 is disconnected and the current Im is disconnected. .

FIG. 3D shows the operation timing of the electromagnetic coil 43. The electromagnetic coil 43 includes the current supply unit 5
The magnetic force required for the connection is maintained while the current Im from 0 is at a level sufficient to maintain the connection of the first and second safing sensor contact portions 41 and 42. That is, collision G
Even when the generation timing of the value (acceleration value) is completed, the electromagnetic coil 43 is controlled in accordance with the current Im from the current supply unit 50.
Thus, the connection state of the first safing sensor contact portion 41, and further, the connection state from the airbag ignition power supply VDC to the point A is maintained.

(E) shows the output timing of the ignition signal. The microcomputer 30 determines a collision based on a signal from the G sensor 31 and outputs a first-stage ignition signal to the ignition switching elements 3 and 4 (for example, 20 ms) slightly later than the time of the collision. A one-stage expansion operation is performed. Next, a predetermined delay period (for example, 100 m
After s), when the second-stage ignition signal is output to the ignition switching elements 3S and 4S (for example, 20 ms), the second-stage inflation operation of the airbag is executed.

As described above, during the period in which the first safing sensor contact portion 41 is connected and the airbag ignition power supply VDC is connected to the point A of the ignition circuit, the ignition signal of the first stage is supplied to the ignition switching element. When the signals are output to the terminals 3 and 4, the circuit including the ignition switching elements 3 and 4, the squib 5, and the current detector 6 conducts from the point A to the ground line, and passes through the first safing sensor contact 41. The electric power supplied to the point A from the airbag ignition power supply VDC heats the squib 5 and gasifies the explosive opposed to the squib 5,
A first stage inflation of the airbag takes place. When the second-stage ignition signal is output to the ignition switching elements 3S and 4S, the circuit including the ignition switching elements 3S and 4S, the squib 5S, and the current detector 6S conducts from the point A to the ground line. The electric power supplied to the point A from the airbag ignition power supply VDC via the first safing sensor contact portion 41 heats the squib 5S and gasifies the explosive opposed to the squib 5S. A second stage (final stage) expansion is performed.

That is, energization of the electromagnetic coil 43 from the current supply unit 50 is started when a collision acceleration occurs and the second safing sensor contact unit 42 is connected, and the capacity of the capacitor 52 and the electromagnetic coil 43 The process ends after a predetermined energization time according to the reactance or the like. Therefore, when the second safing sensor contact portion 42 is once connected in accordance with the acceleration during rough road running or the like, power is supplied to the electromagnetic coil 43 from the current supply portion 50 for a predetermined time (for example, 200 ms).
Even if the first and second safing sensor contact portions 41 and 42 are connected by electromagnetic force, after a predetermined time, the current Im from the current supply unit 50 to the electromagnetic coil 43 decreases and the electromagnetic force is reduced. Since the level becomes low and the first and second safing sensor contact portions 41 and 42 return to the non-connection state,
After the predetermined energization time has elapsed, even if signal processing of a microcomputer or the like malfunctions due to electromagnetic noise or the like, inappropriate deployment of the airbag can be avoided.

Next, an airbag starting circuit according to a second embodiment of the present invention will be described with reference to FIG.

FIG. 4 is a configuration diagram showing a configuration of an airbag starting circuit according to a second embodiment of the present invention. 1 and 2 are denoted by the same reference numerals and description thereof is omitted.

Reference numeral 60 denotes a first switch, which is a connection switch for connecting the point C of the current supply unit 50 to the second safing sensor contact 42, and includes semiconductor switching elements 61 and 62 and resistors 63 and 64. The connection switch unit 60 is normally in a non-connection state. Further, when an ignition current is output to the first-stage (first-stage) ignition circuit, the current detector 6 outputs a signal L (low) of the control signal D2 indicating a state where the ignition current is present, and this signal L (low) is output. ) Is input to the connection switch unit 60, and the connection switch unit 60 is connected. The control signal D2 from the current detector 6 becomes a signal L (low) at the time when the ignition current of the first stage (first stage) ignition circuit is energized, and then at the time when the energization is ended (ends within, for example, 20 ms after the energization). Signal H (high). However, the connection switch unit 60 is configured as shown in FIG. 4 using the semiconductor switching elements 61 and 62 (once the ON signal is input and the connection state is turned on, the connection state is maintained even if the ON signal ends). Is a known configuration as a transistor equivalent circuit of a thyristor). Therefore, even if the connection is once made by the input of the signal L (low) and then switched to the input of the signal H (high), The state is maintained.

With this configuration, the microcomputer 30 further determines the acceleration signal from the G sensor under the condition that the second safing sensor contact portion 42 is connected due to the effect of the collision acceleration, and The ignition signal of the stage outputs an ignition signal to the ignition switching elements 3 and 4 to supply an ignition current, an L signal (low level) is output from the current detector 6, and the connection switch unit 60 is continuously connected. When the power supply unit 50 is turned on, the power supply to the electromagnetic coil 43 is started from the point C of the current supply unit 50, and thereafter, the power supply of the electric charge stored in the capacitor 52 is continued from the point C of the current supply unit 50 (see FIG. 2). This is the same as described above).

Next, the operation timing of the airbag starting circuit according to the second embodiment will be described with reference to FIG.

FIG. 5 is a timing chart showing the timing according to the second embodiment of the present invention. In addition,
The same reference numerals as in FIG. 3 denote the same parts, and a description thereof will be omitted.

(A) shows the timing at which the collision G value (acceleration value) occurs.

FIG. 7B shows the connection timing of the first and second safing sensor contact portions 41 and 42. During the period in which the acceleration exceeds the predetermined threshold value, the first and second safing sensor contact portions 41,
42 (contacts 413 and 423) are connected. on the other hand,
When the control signal D2 is output, the connection switch unit 60 switches to the connection state. At this time, since the second safing sensor contact unit 42 is connected, the current Im from the point C of the current supply unit 50 is reduced. When the electromagnetic coil 43 is energized, the electromagnetic coil 43 generates a magnetic force (electromagnetic force), and the connection state of the first and second safing sensor contacts 41 and 42 (contacts 413 and 423) is maintained during the energization time. . The connection state according to the generation of the magnetic force is started at the same time as the output of the ignition signal as shown by the connection state shown by the solid line,
While the current Im is at a level sufficient to electromagnetically connect the first and second safing sensor contact portions 41 and 42. That is, even if the acceleration decreases and the magnetic force from the permanent magnet 45 disappears and the first and second safing sensor contact portions 41 and 42 return to the non-connection state, the electromagnetic force of the electromagnetic coil 43 causes the electromagnetic force by the contact 413 and contact 413. 42
As long as 3 remains at a level that overcomes the resilient force that is about to separate, it will retain the connection. In the figure (C)
Indicates the output timing of the control signal D2 from the current detector 6. The control signal D2 is output in synchronization with the output of the ignition signal.

FIG. 4D shows the current Im of the current supply unit 50.
3 shows the output timing. Once the second safing sensor contact section 42 is connected by acceleration and the signal L (low) of the control signal D2 is input to the connection switch section 60, the output of the current Im from the current supply section 50 is started. The discharge of the electric charge from the capacitor 52 continues, but when the current Im decreases and reaches the lower limit of the current Im that generates an electromagnetic force capable of connecting the first and second safing sensor contact portions 41 and 42, No. 2 safing sensor contact 42 is disconnected, and the current Im is cut off.

(E) in the figure shows the operation timing of the electromagnetic coil 43. The electromagnetic coil 43 includes the current supply unit 5
The magnetic force required for the connection is maintained while the current Im from 0 is at a level sufficient to maintain the connection of the first and second safing sensor contact portions 41 and 42. That is, collision G
Even when the generation timing of the value (acceleration value) is completed, the electromagnetic coil 43 is controlled in accordance with the current Im from the current supply unit 50.
Thus, the connection state of the first safing sensor contact portion 41, and further, the connection state from the airbag ignition power supply VDC to the point A is maintained.

FIG. 4F shows the output timing of the ignition signal.

As described above, during the period in which the first safing sensor contact portion 41 is connected and the airbag ignition power supply VDC is connected to the point A of the ignition circuit, the first stage ignition signal,
Since the ignition signals of the second stage are sequentially output, the airbags that are deployed in multiple stages perform the first stage inflation and the second stage inflation after a predetermined delay time as described with reference to FIG. Will be done.

That is, from the current supply unit 50 to the electromagnetic coil 4
The current Im is supplied to the first and second sensors 3 and 4 when the microcomputer 30 determines the acceleration signal from the G sensor and the condition that the second safing sensor contact 42 is connected by the action of the collision acceleration.
The process is started when both of the conditions for energizing the stage expansion ignition current and outputting the signal L (low) of the control signal D2 from the current detector 6 are satisfied. The process ends after a predetermined energization time according to the reactance or the like. Conventionally, in a safing sensor not provided with the electromagnetic coil 11, after the first and second safing sensor contact portions 41 and 42 are once connected in accordance with the acceleration, the first mechanical contact is provided in response to the hunting of the collision acceleration. The connection between the second safing sensor contact portions 41 and 42 is also interrupted, and there is a problem that the squib heating energy is insufficient due to the ignition current even if the microcomputer 30 outputs an ignition signal. At the beginning, the electromagnetic coil 43 is energized, and the connection of the first and second safing sensor contact portions 41 and 42 is maintained by the electromagnetic force, so that the ignition operation is ensured and the final stage of the multi-stage expansion. Up to (for example, 20
0 ms), first and second safing sensor contact portions 4
1, 42 can be connected. When a safing sensor having the conventional electromagnetic coil 11 is used, signal processing of a microcomputer or the like malfunctions due to electromagnetic noise or the like, and the safing sensor contact portion 1 is continuously connected,
At the same time, when an ignition signal is output due to a malfunction of the microcomputer 36, the deployment of the airbag may become inappropriate. However, according to the second embodiment, the ignition current is detected and the connection switch unit 60 is activated. Shortly after connection (for example, 2
00 ms), the first and second safing sensor contact portions 41 and 42 are connected only by electromagnetic force, so that this problem can be avoided. In addition, the first and second safing sensor contact portions 41 and 4 are unexpectedly dropped due to a rough road or the like.
When the ignition switch 2 is connected, a short time (for example, 200 ms) immediately after the ignition current is detected and the connection switch unit 60 is connected.
Only the connection of the first and second safing sensor contact portions 41 and 42 by the electromagnetic force is not performed, so that the airbag can be appropriately deployed even if the influence of acceleration due to a bad road is present.

FIG. 6 is a configuration diagram showing the configuration of the airbag starting circuit according to the third embodiment of the present invention. 1, 2, and 4 are denoted by the same reference numerals and description thereof is omitted.

Reference numeral 70 denotes a second switching means, which is a connection switch for connecting the point C of the current supply unit 50 to the second safing sensor contact 42. The connection switch 70 is connected to the semiconductor switching element 71 and the resistors 72 and 73. Be composed.
The connection switch unit 70 is normally in a non-connection state. When an ignition signal is output to the first-stage (first-stage) ignition circuit, the microcomputer 30 starts to output the first-stage (first-stage) ignition current, and then the microcomputer 30 needs to connect the second safing sensor contact portion 42 to the predetermined position. During this time, the signal L (low) of the control signal D3 is output, and the signal L (low) is input to the connection switch unit 70, and the connection switch unit 70 is connected.

With this configuration, the microcomputer 30 further outputs the first-stage ignition signal to the ignition switching element 3 under the condition that the second safing sensor contact portion 42 is connected due to the effect of collision acceleration. , 4 from the time when the ignition signal is output to the output period of the second-stage ignition signal (that is, the period in which the airbag ignition power supply VDC needs to be connected to the point A), and the control signal D
3 outputs the L signal (low level) of the connection switch 7
0 is set to the connected state, and the current Im is supplied to the electromagnetic coil 43 from the point C of the current supply unit 50.

Next, the operation timing of the airbag activation circuit according to the third embodiment will be described with reference to FIG.

FIG. 7 is a timing chart showing the timing according to the third embodiment of the present invention. In addition,
The same symbols are assigned to the same explanations as in FIG. 5, and explanations are omitted.

(A) shows the timing at which the collision G value (acceleration value) occurs.

FIG. 7B shows the connection timing of the first and second safing sensor contact portions 41 and 42. During the period in which the acceleration exceeds the predetermined threshold value, the first and second safing sensor contact portions 41,
42 (contacts 413 and 423) are connected. on the other hand,
When the control signal D3 is output, the connection switch unit 70 switches to the connection state. At this time, since the second safing sensor contact section 42 is being connected, the electromagnetic coil 43 is energized from the point C of the current supply section 50, and the electromagnetic coil 43 generates an electromagnetic force. The connection state of the ring sensor contact portions 41 and 42 (contacts 413 and 423) is maintained. The state of the connection state according to the generation of this electromagnetic force is shown in FIG.
Therefore, the description is omitted.

FIG. 9C shows the output timing of the control signal D3 from the current detector 6. Control signal D3
The microcomputer 30 outputs the L signal (low level) of the control signal D3 from the output point of the first stage ignition signal to the output period of the second stage ignition signal.

FIG. 9D shows the current Im of the current supply unit 50.
3 shows the output timing. Once the second safing sensor contact section 42 is connected by acceleration and the signal L (low) of the control signal D3 is input to the connection switch section 70, the connection switch section 70 is connected and the current supply section 50 The current Im is output. With the input of the signal L (low) of the control signal D3, the discharge of the electric charge from the capacitor 52 continues, but the current Im decreases and the electromagnetic force capable of connecting the first and second safing sensor contact portions 41 and 42. Is reached, the second safing sensor contact 42 is disconnected, and the current Im is cut off.

FIG. 9E shows the operation timing of the electromagnetic coil 43. The electromagnetic coil 43 includes the current supply unit 5
It operates according to the period when the output from 0 is supplied. That is, during the operation period of the electromagnetic coil 43, the first
Is connected, and the connection state of the airbag ignition power supply VDC to the point A of the ignition circuit is maintained.

FIG. 9F shows the output timing of the ignition signal.

As described above, during the period when the first safing sensor contact portion 41 is connected and the airbag ignition power supply VDC is connected to the point A of the ignition circuit, the ignition signal of the first stage is output.
Since the ignition signal of the second stage is sequentially output, the airbag that is deployed in multiple stages is inflated at the first stage, and after a predetermined delay time, the second stage ignition signal is output, as described with reference to FIG. 3 or FIG. Is expanded.

That is, from the current supply unit 50 to the electromagnetic coil 4
The current Im supplied to the current supply unit 3 starts when the microcomputer 30 outputs the first-stage ignition signal in a situation where the collision acceleration is occurring, and the current Im is supplied from the current supply unit 50 for a predetermined time. , For example, in a 200 ms energization period.
Therefore, even if the signal processing of the microcomputer 30 or the like malfunctions and the L signal (low level) of the control signal D3 is constantly output, the ignition circuit of the airbag ignition power supply VDC is connected to the point A. Since the time during which the microcomputer is in operation is transiently short (for example, 200 ms), even if a malfunction in which the microcomputer further outputs an ignition signal during the constant output of the L signal (low level) (due to a malfunction) occurs, the airbag is not affected. Can be prevented from being deployed inappropriately.

As described above, according to the first embodiment, the second embodiment and the third embodiment of the present invention, the electromagnetic force for connecting the first safing sensor contact portion 41 is provided. A current supply unit 50 that supplies a drive current for the coil 43;
Since the time constant circuit is formed by the capacitor 52 and the resistor 51, the time width for connecting the first safing sensor contact portion 41 can be set to, for example, 200 ms after the start of energization.

In the conventional airbag activation circuit, there is a concern that signal processing of the microcomputer 36 and the like may malfunction due to electromagnetic noise and the like, but the energization from the current supply unit 50 is started on the premise of a collision acceleration. The provision of a conducting path for the electromagnetic coil 43 from the current supply unit 50
The connection time of the airbag ignition power supply VDC to the point A of the ignition circuit only in the signal state under the collision state (first safing sensor contact point) (By connection of the portion 41), the airbag can be deployed appropriately.
In a multistage deployment type airbag, a plurality of squibs are ignited with a time difference. However, since the deployment stage of the final stage (output time of the ignition signal of the final stage) corresponds to the time after the collision acceleration has disappeared. There is a problem that the ignition current is not supplied.
(For a period of 00 ms), the first safing sensor contact portion 41 is in a connected state until the final stage deployment time (the last stage ignition time). Can be started. Further, in the above embodiment, even if the second safing sensor contact portion 42 is suddenly connected due to a bad road or the like and the electromagnetic coil 43 is energized, the energization is stopped when the discharge of the capacitor is completed. Thus, the second safing sensor contact portion 42 can be prevented from being kept connected, and fail-safe can be achieved. Although the occupant protection means of this embodiment includes airbags such as a driver's seat and a passenger's seat, the invention is not limited to this, and may be applied to a seatbelt pretensioner or a rollover airbag.

[0063]

As described above in detail, according to the present invention, the contacts of the safing sensor are interposed between the power supply and the holding means, and the contacts of the safing sensor are connected by a mechanical shock. Since the connection is held, the safing sensor is held independently of the microcomputer, and the airbag or the like can be appropriately deployed regardless of the malfunction of the microcomputer. Further, since the contacts of the safing sensor are held until the last squib is ignited, the contacts of the safing sensor can be reliably held even in multistage deployment.

Moreover, even if the contacts of the safing sensor are accidentally connected due to some impact, the power supply of the holding means is limited, so that the connection state can be eventually released and fail safe can be achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a structure of a safing sensor according to an embodiment of the present invention.

FIG. 2 is a configuration diagram illustrating a configuration of an airbag activation circuit according to the first embodiment of the present invention.

FIG. 3 is a timing chart showing signal timing according to the first embodiment of the present invention.

FIG. 4 is a configuration diagram illustrating a configuration of an airbag activation circuit according to a second embodiment of the present invention.

FIG. 5 is a timing chart showing signal timing according to a second embodiment of the present invention.

FIG. 6 is a configuration diagram illustrating a configuration of an airbag activation circuit according to a third embodiment of the present invention.

FIG. 7 is a timing chart showing signal timing according to a third embodiment of the present invention.

FIG. 8 is a configuration diagram showing a configuration of a conventional airbag activation circuit.

FIG. 9 is an explanatory view illustrating the structure of a conventional safing sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 3 ... Semiconductor switching element 5 ... Squib 6 ... Current detection part 30 ... Control part 31 ... G sensor 40 ... Saving sensor 41,42 ... First and second Safety sensor contact part 43 ... Coil 50 ... Current supply part 51 ... Resistor 52 ... Capacitor 60,70 ... Connection switch part 61,71 ... Semiconductor switching element

Claims (6)

[Claims] 1. A safing sensor in which a contact is connected according to the acceleration of a vehicle, an occupant protection means for protecting an occupant of the vehicle, and a squib for igniting explosive, wherein the contact of the safing sensor is An occupant protection device that activates the occupant protection unit when the squib is energized when the connection state is established, comprising a power supply and a holding unit configured to maintain a connection state of a contact point of the safing sensor by power supply from the power supply. An occupant protection device, wherein a contact point of the safing sensor is interposed between the power supply and the holding unit. 2. A safing sensor whose contacts are connected according to the acceleration of the vehicle, occupant protection means for protecting occupants of the vehicle, and a squib for igniting explosive, wherein the contacts of the safing sensor are provided. An occupant protection device that activates the occupant protection means when the squib is energized when the connection state is established; a power supply; holding means for holding the connection state of the contacts of the safing sensor by power supply from the power supply; And a first switching unit that is in a connected state when a current is supplied, and a contact of the safing sensor and the first switching unit are interposed between the power supply and the holding unit. Characteristic occupant protection device. 3. A safing sensor whose contacts are connected according to the acceleration of the vehicle, occupant protection means for protecting occupants of the vehicle, and a squib for igniting explosive, wherein the contacts of the safing sensor are provided. When the squib is energized, the squib is energized, and in the occupant protection device that activates the occupant protection means, a power supply; and a holding unit configured to hold a connection state of a contact of the safing sensor by power supply from the power supply; A second switching unit that is in a connected state when a collision is determined based on acceleration, wherein a contact point of the safing sensor and a second switching unit are interposed between the power supply and the holding unit. An occupant protection device characterized in that: 4. The safing sensor includes two contacts that are interlocked with each other, and the holding unit is configured to generate a magnetic force for maintaining a connection state between the two contacts of the safing sensor by supplying power from the power supply. The coil, wherein one contact of the safing sensor is connected to the squib, and the other contact is connected between the electromagnetic coil and the power supply. Item 3. The occupant protection device according to item 3. 5. The occupant protection device according to claim 1, wherein the power supply includes a capacitor, and a holding time of the holding unit is defined by discharging the capacitor. 6. The squib is provided in a plurality of stages, and the holding time of the holding unit includes a period from a timing of energizing the first stage squib to a timing of energizing the last stage squib. Item 7. The occupant protection device according to item 5.