JPH06239187A - Occupant crash protection - Google Patents

Abstract

PURPOSE:To surely make starting means operable by the electric charge of a back-up capacitor. CONSTITUTION:The device is provided with impact detecting means 6 and 24 which are connected in series between a battery 1 and an auxiliary power supply 3, and are tuned on upon detecting impact equal to or more than a specified value, and with monitor resisters 6b and 25 which are connected to the impact detecting sensors in parallel, and detect disconnection and shortcircuit, and let a switching element 32 connected to the monitor resistors in series be turned on when electricity supply from the on-vehicle battery is suspended.

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 such as an airbag and a seat belt pretensioner which protects an occupant by detecting a collision of a vehicle and operating it.

[0002]

2. Description of the Related Art FIG.
FIG. 4 is a circuit diagram showing a conventional occupant protection device disclosed in Japanese Patent Publication No. 3), in which 1 is a vehicle battery and 2 is a switch for supplying power to an airbag device as a occupant protection device, which is usually an engine key switch. Is also used. Reference numeral 3 denotes a backup power supply, which is composed of a backup capacitor 3a, a charging resistor 3b, and a diode 3c, and is used as an auxiliary power supply capable of supplying a sufficient current to the airbag deploying means 5 even if the battery is lost during a collision. 4,
Reference numeral 6 denotes a G sensor as an impact detection sensor, which is composed of contact portions 4a and 6a that detect deceleration at the time of collision and turn on, and resistors 4b and 6b that flow a minute current for failure diagnosis. . In addition, 7 is a reverse current blocking diode, 8 is G
A failure detection signal line for the sensors 4 and 6, and a short / open failure detection signal line 9 for the airbag deployment means 5.

Next, the operation will be described. In this conventional example, by using the signal lines 8 and 9, the G sensors 4 and 6 are
Also, the failure of the airbag deployment means 5 is detected. For example, when detecting a failure of the G sensors 4 and 6, the resistance 4
By measuring the voltage divided by b and 6b using the G sensor failure detection signal line 8, the G sensor 4 and 6 are detected.
Detects disconnection and short circuit. If the battery 1 comes off due to a collision and the G sensors 4 and 6 detect the collision immediately after that, and a current has to flow to the airbag expanding means 5, the backup power source 3 causes the airbag expanding means 5 to flow. Is supplied with the necessary current. This allows the airbag to be deployed.

[0004]

Since the conventional occupant protection device is constructed as described above, when the backup capacitor 3a has a small capacity, the battery 1 is disconnected from the circuit due to a collision accident of the vehicle. By the time the sensors 4 and 6 detect the collision, most of the electric charge of the backup capacitor 3a is consumed by the resistors 4b and 6b, and as a result, a necessary current can be supplied to the airbag expanding means 5. There were problems such as disappearance. Further, the current supply to the airbag expanding means 5 is controlled by the resistors 4b,
The capacity of the backup capacitor 3a must be made extremely large in order to make it possible despite the consumption by 6b, which causes problems such as an increase in cost and an increase in size of the system.

The present invention has been made in order to solve the above-mentioned problems, and when the battery is removed, the monitor resistor circuit is immediately disconnected from the backup power source so that the charge of the backup capacitor becomes It is possible to obtain an economical occupant protection device that prevents consumption by a monitor resistor and therefore can reliably activate an activation means such as an airbag with sufficient energy even when a small-capacity backup capacitor is used. To aim.

[0006]

An occupant protection system according to the present invention includes an impact detection sensor which is connected in series between a starting means, a battery and an auxiliary power source and which is turned on when an impact of a set value or more is detected. , Provided with a monitor resistor that is connected in parallel to the impact detection sensor and detects a disconnection or a short circuit of the impact detection sensor, and connects a switching element connected in series to the monitor resistor when the power supply from the vehicle-mounted battery is stopped. ,
It is designed to be turned off.

[0007]

In the occupant protection system according to the present invention, when the battery is removed from the circuit at the time of collision of the automobile, the monitoring resistor is used as the backup capacitor by the switching element until all the contact portions of the G sensor are turned on. The discharge resistance of the discharge circuit is prevented from being wasted by the monitor resistance during this period, and the contact portion is turned on subsequently so that the discharge energy of the backup capacitor can be sufficiently supplied to the starting means.

[0008]

【Example】

Example 1. An embodiment of the present invention will be described below with reference to the drawings. 1, 24 is a G sensor having a structure different from that of the G sensor 4 of FIG. 2, 24a is a contact portion which is turned on by detecting deceleration at the time of collision, and 24c and 24d are batteries 1
And a connection terminal of the G sensor 24, which is connected to the airbag deployment means 5 composed of an electric resistor as the airbag deployment means (starting means). Also, 24e, 24f
Is a terminal for connecting the monitor resistor 25 in parallel to the contact portion 24 a, and the monitor resistor 25 is connected to the outside of the G sensor 24.

Further, 32 is a PNP transistor as a switching element having an emitter and a collector connected in series to the monitor resistor 24, and 33 is an NPN transistor as a switching element having a collector connected to the base of the PNP transistor 32. The emitter of the transistor 33 is grounded, and the base is connected to the battery 1 via the resistor 34 and the switch 2 and to the ground via the resistor 35. Reference numeral 36 is a reverse current blocking diode. The other circuit parts that are the same as those shown in FIG. 2 are designated by the same reference numerals, and the duplicated description thereof will be omitted.

Next, the operation will be described. Now, when the switch 2 is in the ON state and a collision accident occurs while the vehicle is running, the G sensor (impact detection sensor) 24, 6
When the contact portions 24a, 6a of the above are turned on at the same time, a current flows from the battery 1 to the airbag expanding means 5, and the airbag is expanded. On the other hand, in the case of the collision accident, when the battery 1 is detached, no power is supplied from the battery 1,
Power is supplied to each G from the backup capacitor 3a of the backup power supply (auxiliary power supply) 3 which is a precharged auxiliary power supply.
It is supplied to the sensors 24 and 6.

In this case, after the battery 1 is detached due to the collision, the contact portions 24a of the G sensors 24 and 6 are
There is a slight time difference until the 6a is turned on, and during this time difference, the charge of the backup capacitor 3a tends to flow through the monitor resistors 25 and 6b. However, the resistors 34 and 35 detect that the battery 1 is detached and the voltage applied to the base of the transistor 33 is reduced, whereby the transistors 3 as switching elements are switched.
In order to turn off 3, 32, the monitor resistors 25, 6b
To the backup capacitor 3a
Charge is never lost. Note that there is a negligible spontaneous discharge until a current flows through the airbag expanding means 5. Therefore, the charge of the backup capacitor 3a is changed by the subsequent ON operation of the contact portions 24a and 6a.
All can be supplied to the airbag deploying means 5, and the airbag can be reliably deployed with a large amount of energy. Therefore, it is possible to avoid the inconvenience of preparing a backup capacitor having a large capacity in consideration of the charge discharge to the monitor resistors 25 and 6b during the above-mentioned time difference, which is also advantageous in cost.

Further, in this embodiment, by connecting the monitor resistor 25 to the outside of the G sensor 24 via the terminals 24e and 24f, a low-cost G sensor 24 can be used, and circuit maintenance is also possible. The advantage is that it becomes easier.

[0013]

As described above, according to the present invention, an impact detection sensor which is connected in series between a battery and an auxiliary power source and is turned on when an impact greater than a set value is detected, and the impact detection sensor. Provided with a monitor resistor which is connected in parallel and which detects a disconnection or a short circuit, and a switching element which is connected in series to the monitor resistor is turned off when the power supply from the vehicle battery is stopped. Since it is configured, it is possible to prevent meaningless loss due to the monitor resistance of the electric charge of the backup capacitor as in the conventional case. Therefore, despite using the discharge of the small-capacity backup capacitor, sufficient energy is required for the airbag and seat belt. There is an effect that a starter such as a pretensioner can be reliably operated and that this can be realized with an inexpensive structure.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an occupant protection device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a conventional occupant protection device.

[Explanation of symbols]

 1 Battery 3 Backup Power Supply (Auxiliary Power Supply) 3a Backup Capacitor 5 Airbag Deployment Means (Starting Means) 6,24 G Sensor (Impact Detection Sensor) 6b, 25 Monitor Resistor 32 Switching Element

Claims (1)

[Claims] 1. An auxiliary power supply having a backup capacitor charged with a vehicle-mounted battery as a power supply, and an electric resistor for operating an occupant protection means by receiving a current of a set level or more supplied from the auxiliary power supply or the battery. And a shock detection sensor which is connected in series between the start means and the battery and the auxiliary power supply and is turned on when a shock of a set value or more is detected, and a shock detection sensor which is connected in parallel to the shock detection sensor. An occupant protection device comprising: a monitor resistor for detecting a disconnection or a short circuit of the monitor resistor; and a switching element connected in series to the monitor resistor and turned off when supply of power from the battery is stopped.