JPH11321543A - Occupant restraint - Google Patents

Abstract

(57) [Problem] To provide an occupant restraint device capable of avoiding the influence of noise with a simple shield structure using a plurality of the same sensors. SOLUTION: A G sensor 11 having a shield case 9 for avoiding the influence of external noise, and a G sensor 13 which is under the influence of the external noise and is provided substantially adjacent to the G sensor 11 are respectively output. When the difference value between the voltage signals is less than the predetermined threshold value, the CPU 17 performs a difference process S50 for determining that the vehicle has collided, and arranges them on the same printed circuit board 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an occupant restraint device, and more particularly to an occupant restraint device capable of avoiding the influence of noise with a simple shield structure using a plurality of identical sensors.

[0002]

2. Description of the Related Art Conventionally, in an occupant restraint system mounted on a vehicle, a G sensor for detecting an impact at the time of a collision is dispersedly arranged at a center console portion, a door portion, and the like of the vehicle, and the The degree of impact is monitored by a control unit provided at one location, and it is determined by a predetermined calculation whether or not the vehicle has collided, and it is determined whether or not to deploy the airbag module.

In recent years, in order to secure the degree of freedom in the layout of various units, reduce the number of harnesses, and the like, it is desired to control the airbag module of each unit with a unit having a plurality of G sensors and a control unit provided in one place. Is coming.

[0004]

However, when a plurality of G sensors are arranged in one unit, each G sensor is
If the sensor is affected by extraneous noise, a filter for reducing the effect of extraneous noise on the voltage signals from the individual G sensors can be used to separate the voltage signal caused by the impact from the voltage signal affected by the extraneous noise. It is necessary to add a circuit and a noise elimination circuit, which complicates the circuit configuration and increases the manufacturing cost.

[0005] The present invention has been made in view of the above,
An object of the present invention is to provide an occupant restraint system having a noise resistance performance similar to that of the related art even when external noise is applied, with a simple configuration and at low cost.

[0006]

According to the first aspect of the present invention,
In order to solve the above-mentioned problem, the vehicle has an acceleration sensor for detecting a degree of impact applied to the vehicle, and deploys an airbag module in the vehicle compartment when it is determined from the output signal of the acceleration sensor that the vehicle has collided. An occupant restraint system, comprising: a first acceleration sensor having a shield case for avoiding the influence of extraneous noise; and a first acceleration sensor under influence of extraneous noise and provided substantially adjacent to the first acceleration sensor. When the difference value between the second acceleration sensor substantially the same as the first acceleration sensor and the signal output from each of the first and second acceleration sensors is less than a predetermined threshold,
The gist of the invention is to have a difference means for judging that the vehicle has collided.

[0007]

According to the first aspect of the present invention, the first acceleration sensor having the shield case for avoiding the influence of the external noise, and the first acceleration sensor under the influence of the external noise and It is determined that the vehicle has collided when a difference value between signals output from the first acceleration sensor and the second acceleration sensor substantially identical to each other is less than a predetermined threshold value. Thus, it is possible to cancel the influence of the external noise applied to the substantially same acceleration sensor.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing the configuration of an occupant restraint system according to one embodiment of the present invention.

As shown in FIG. 1, an occupant restraint system 1 includes a battery 3 mounted on a vehicle and supplying power to electronic devices,
Ignition that is turned on from the start of the engine
The switch IGN_SW5, the printed circuit board 7 on which the G sensor is mounted, the shield case 9 covering the G sensor 11 for avoiding the influence of external noise, and substantially the same that output a voltage signal according to the degree of impact applied to the vehicle G sensors 11 and 13 composed of the semiconductor elements described above, a power supply circuit 15 for stabilizing the power supply voltage supplied from the battery 3, and whether the vehicle has collided based on the voltage signals output from the G sensors 11 and 13. CPU 17 to determine, an ignition transistor TR for outputting an ignition current to the squib 19 in response to an ignition signal (High level) output from an output terminal Vo of the CPU 17 when the vehicle collides, and when an ignition current is applied. And a squib 19 for deploying an airbag module (not shown).

It is assumed that the G sensors 11 and 13 are provided substantially adjacent to each other on the printed circuit board 7.

FIG. 2A is an external view of the shield case 9 covering the G sensor 11, FIG. 2B is a top view of the printed circuit board 7 viewed from above the mounting surface, and FIG. 2B is a bottom view of the printed circuit board 7 viewed from the solder surface. It is a figure (c).

The shield case 9 is a case formed by rolling and forming a material such as phosphor bronze, and is a member having an effect of preventing the transmission of external noise by grounding. FIG.
As shown in FIG. 2A, a plurality of leads 31 are provided at a lower portion of the shield case 9, and lead holes formed so as to cover the G sensor 11 attached to the printed circuit board 7 shown in FIG. 33 is the lead 31 of the shield case 9
Is inserted. The lead 31 of the shield case 9 inserted into the lead hole 33 of the printed board 7 is solid grounded on the solder surface on the printed board 7 as shown in FIG. As a result, the G sensor 11 is covered by the shield case 9 and the printed circuit board 7 and can avoid the influence of external noise.

Next, referring to FIG. 4, the CPU shown in FIG.
The operation of the occupant restraint device will be described based on the processing functions (S10 to S60). The G sensors 1 and 2 shown in FIG. 3 are G sensors 11 and 13, respectively, and the following description will be made using the G sensors 1 and 2.

First, according to the algorithm 1 shown in the processing function S10, when the voltage signal output from the G sensor 1 is equal to or more than a predetermined reference value, it is determined that the vehicle has collided, and is output from the G sensor 1. If the voltage signal is equal to or less than the reference value, it is determined as a noise level. next,
In the algorithm 2 shown in the processing function S20, the G sensor 2
If the voltage signal output from the G sensor 2 is equal to or higher than a predetermined reference value, it is determined that the vehicle has collided. If the voltage signal output from the G sensor 2 is equal to or lower than this reference value, it is determined that the vehicle is in the noise level. I do.

Next, in the integration processing shown in the processing function S30, the previous value and the current value of the voltage signal output from the G sensor 1 are added to obtain the current integration value. As a result, FIG.
As shown in (a), when an impact is applied to the G sensor 1, the level becomes as shown by the broken line (a). When the G sensor 1 is detecting noise whose level has been lowered by the shield case, the level becomes the level shown by the solid line (b).

Next, in the integration processing shown in the processing function S40, the previous value and the current value of the voltage signal output from the G sensor 2 are added to make the current integration value. As a result, FIG.
As shown in (b), when an impact is applied to the G sensor 2, the level becomes as shown by the solid line (c). Similarly, when the high-level external noise is detected by the G sensor 2, the level becomes the level shown by the solid line (c). That is, the G sensor 2
Even if an integration process is performed on the voltage signal output from the G sensor 2, it cannot be determined whether the G sensor 2 receives an impact generated at the time of a collision or detects a high-level external noise.

Here, in the difference processing shown in the processing function S50, the integration processing S is performed based on the integration value obtained in the integration processing S40.
The difference value between the two is obtained by subtracting the integral value obtained in 30. As a result, as shown in FIG. 4C, when an impact is applied to the G sensors 1 and 2, the level becomes a level shown by a solid line (d), and a difference value lower than a predetermined threshold line is output. Therefore, it is determined as an impact generated at the time of collision. On the other hand, as shown in FIG. 4D, when an external noise is occurring, the level becomes a level shown by a solid line (e), and a difference value higher than a predetermined threshold line is output. I do.

Next, in the logical product processing shown in the processing function S60, the determination result values of the algorithms 1 and 2 and the difference processing S60
The logical product is obtained based on the judgment result value at 50.

As a result, the impact applied to the vehicle at the time of the collision is G
If it is detected by the sensors 1 and 2, the logical product processing S
60 outputs a logical value “1” representing the ignition signal. That is, when the vehicle collides, the transistor TR is turned on in response to an ignition signal (High level) output from the output terminal Vo of the CPU 17, an ignition current flows through the squib 19, and the squib 19 is heated and the airbag module is heated. (Not shown) will be developed.

On the other hand, when noise is applied to the G sensor, a logical value "0" indicating non-operation is output from the logical product processing S60. That is, the transistor TR is off.

As described above, the G sensor 11 having the shield case 9 for avoiding the influence of the external noise and the G sensor 13 provided under the influence of the external noise and provided substantially adjacent to the G sensor 11 are respectively provided. When the difference value between the output voltage signals is less than the predetermined threshold, the CPU 17 performs a difference process S50 of determining that the vehicle has collided,
By arranging them on the same printed circuit board 7, it is possible to cancel the influence of extraneous noise applied to the substantially identical G sensors 11, 13. As a result, it is possible to provide an occupant restraint system having the same noise resistance performance as the conventional one with a simple configuration and at low cost.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an occupant restraint device according to one embodiment of the present invention.

FIGS. 2A and 2B are an external view of a shield case 9 covering a G sensor 11, a top view of the printed board 7 viewed from above a mounting surface, and a bottom view of the printed board 7 viewed from a solder surface. ).

FIG. 3 is a diagram for explaining processing functions (S10 to S60) of a CPU;

FIG. 4A is a diagram showing an integrated value of the G sensor 1, FIG. 4B is a diagram showing an integrated value of the G sensor 2, FIG. 4C is a diagram showing a difference value at the time of impact, and FIG. It is a figure (d) showing.

[Explanation of symbols]

 9 Shield case 11, 13 G sensor 17 CPU 19 Squib

Claims (1)

[Claims] An occupant restraint for deploying an airbag module in a vehicle cabin when an acceleration sensor for detecting a degree of impact applied to the vehicle is determined to be a collision from an output signal of the acceleration sensor. A first acceleration sensor having a shield case for avoiding the influence of extraneous noise; and a first acceleration sensor under the influence of extraneous noise and provided substantially adjacent to the first acceleration sensor. A second acceleration sensor that is substantially the same as the acceleration sensor, and a difference that determines that the vehicle has collided when a difference value between signals output from the first and second acceleration sensors is smaller than a predetermined threshold value. Means for restraining the occupant.