JPH10119711A - Side air bag starting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow necessary expansion positively while preventing useless expansion in a side air bag starting device for controlling the start of a side air bag. SOLUTION: A longitudinal acceleration sensor 40 is provided to generate a signal Vx corresponding to the longitudinal acceleration Gx of a vehicle. A moving quantity computing circuit 42 integrates Vx twice to compute the characteristic value S*, a threshold value setting circuit 46 sets the expansion threshold value VTHY or a side air bag larger as S* is larger. A start judging circuit 48 supplies a driving signal to a driving circuit 52 in case of the lateral acceleration GY of the vehicle being VTHY or more. Upon receiving the supply of the driving signals, the driving circuit 52 supplies an ignition current to a squib 54 to develop the side air bag.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side airbag activating device, and more particularly to a side airbag activating device for controlling activation of a side airbag deployed between a vehicle seat and a door.

[0002]

2. Description of the Related Art Conventionally, a side airbag has been known as disclosed in, for example, JP-A-7-2049.
The side airbag is built in a vehicle door. Further, the vehicle door has a built-in lateral acceleration sensor for detecting a lateral acceleration acting on the vehicle. The side airbag is deployed so as to extend between the door and the occupant when a lateral acceleration exceeding a predetermined threshold value is detected by the lateral acceleration sensor.

As a vehicle safety device, a driver airbag and a passenger airbag are conventionally known. The driver's seat airbag and the passenger's seat airbag are controlled based on detection values of a longitudinal acceleration sensor that detects longitudinal acceleration acting on the vehicle. Specifically, when the driver's seat airbag and the passenger's seat airbag detect a negative acceleration exceeding a predetermined value by the longitudinal acceleration sensor, that is, a deceleration exceeding the predetermined value, the steering wheel and the driver's seat are separated. Between the dashboard and the passenger seat. Hereinafter, the driver airbag and the passenger airbag are collectively referred to as a front airbag.

As described above, a side airbag deploys in response to a lateral acceleration acting on a vehicle. On the other hand, the front airbag deploys in response to acceleration in the front-rear direction when acting on the vehicle. Therefore, when either the longitudinal acceleration or the lateral acceleration acts on the vehicle, the side airbag and the front airbag do not deploy together.

[0005]

When a vehicle is running, energy may be input from a position offset laterally from the center axis of the vehicle. Hereinafter, such input of energy is referred to as offset input. In such a case, a large deceleration acts on the vehicle in the front-rear direction, and a relatively small acceleration acts on the vehicle in the vehicle width direction.
In this case, the front airbag is deployed immediately after the energy is input to the vehicle, and the side airbag may be deployed slightly after a short time.

When the energy is offset-input to the vehicle, the occupant of the vehicle moves relative to the passenger compartment mainly forward. Therefore, in such a situation, there is little need to deploy the side airbag. Therefore, in such a situation, it is desirable that the side airbag is not unnecessarily deployed in order to reduce the repair cost of the vehicle.

[0007] The above-mentioned requirement is fulfilled by, for example, prohibiting the deployment of the side airbag for a predetermined time after the deceleration of such a degree that the front airbag is deployed acts on the vehicle. According to this processing, when the energy is offset-input to the vehicle, it is possible to reliably prevent the side airbag from being deployed due to the lateral acceleration caused by the energy.

However, when the vehicle is running, the energy may be input from the side of the vehicle a short time after the energy is input from the front of the vehicle. Hereinafter, such an energy input is referred to as an energy composite input. When energy is input to the vehicle in this way,
It is appropriate to first deploy the front airbag when energy is input from the front of the vehicle, and then deploy the side airbag when energy is input from the side of the vehicle.

On the other hand, when the above method is applied, that is, when a large deceleration acts on the vehicle in the front-rear direction,
Thereafter, according to the method of uniformly prohibiting the deployment of the side airbag for a predetermined time, the side airbag cannot be deployed when energy is input from the side of the vehicle. As described above, an appropriate state cannot be realized with respect to a composite input of energy by a technique of preventing the side airbag from being unnecessarily deployed by prohibiting the deployment of the side airbag.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and does not wastefully deploy a side airbag when energy is offset-input, and a side airbag when energy is compositely input. It is an object of the present invention to provide a side airbag activation device that can appropriately deploy the airbag.

[0011]

The above object is achieved by the present invention.
, A characteristic value detecting means for detecting a characteristic value of a relative forward movement amount of the occupant with respect to the seat, a lateral acceleration sensor for detecting a lateral acceleration acting on the vehicle, and an occupant based on the characteristic value. Threshold value setting means for setting the deployment threshold value of the side airbag to a larger value as the amount of forward movement of the side airbag increases, and when the detection value of the lateral acceleration sensor is not less than the deployment threshold value, And a activating means for deploying the airbag.

In the present invention, when a lateral acceleration exceeding the deployment threshold acts on the vehicle, the side airbag is deployed. The deployment threshold value of the side airbag is set to a larger value based on the forward movement amount of the occupant, the larger the movement amount. For this reason, the side airbag
The more the passenger moves forward with respect to the seat, the more difficult it is to deploy. The effect of the side airbag exerts a great effect when the side airbag extends to the side of the occupant when deployed. In other words, when the side airbag is deployed, if the occupant is moving forward to such an extent that the side airbag cannot extend to the side of the occupant, it is difficult to achieve a great effect.

When the threshold for deploying the side airbag is set as in the present invention, the side airbag is not unnecessarily deployed in such a situation. Further, according to the present invention, by preventing the useless deployment of the side airbag by changing the deployment threshold value, energy is input in a short time from both the front and the side of the vehicle. Also in this case, it is possible to reliably deploy the side airbag as needed.

According to a second aspect of the present invention, in the side airbag starting device according to the first aspect, the characteristic value detecting means detects a longitudinal acceleration acting on the vehicle, a longitudinal acceleration sensor, and the longitudinal acceleration sensor. And characteristic value calculating means for calculating the characteristic value based on
The proximity acceleration sensor, the characteristic value calculation means, the threshold value setting means, the lateral acceleration sensor, and the activation determination means are arranged close enough to communicate with each other via analog signals without being affected by noise. The side airbag activation device described above is effective in improving responsiveness.

In the present invention, both the lateral acceleration sensor and the longitudinal acceleration sensor output analog signals. In order for the characteristic value calculating means to calculate the characteristic value accurately and at high speed, the analog signal output from the longitudinal acceleration sensor is supplied to the characteristic value calculating means without digitization, and the characteristic value calculation is performed. Advantageously, the means is used for the operation without digitizing the signal. Similarly, in order to accurately and quickly determine the activation of the side collision airbag in the threshold value setting means and the activation determination means, an analog signal output from the characteristic value calculation means,
Further, it is advantageous to supply the analog signal output from the lateral acceleration sensor to the threshold value setting means and the activation determination means without digitizing.

Analog signals are more susceptible to noise than digital signals. Therefore, when an analog signal is transmitted over a long distance, it is difficult to transmit accurate information. On the other hand, as in the present invention, if all components for transmitting and receiving signals are arranged close enough to properly transmit and receive analog signals, the analog signals can be transmitted to the medium without being affected by noise. The information can be transmitted and received accurately. When accurate communication using an analog signal as a medium is realized, a start determination accurately corresponding to the forward movement amount of the occupant is realized with high responsiveness.

According to a third aspect of the present invention, in the side airbag starting apparatus according to the first aspect, the characteristic value detecting means detects a longitudinal acceleration acting on the vehicle, a longitudinal acceleration sensor, and the longitudinal acceleration sensor. Characteristic value calculating means for calculating the characteristic value based on the threshold value, and the threshold value setting means according to the forward movement amount of the occupant from among a plurality of threshold values based on the characteristic value. The side airbag activation device includes a threshold value selection unit that selects a threshold value, and an A / D conversion unit that converts a detection value of the lateral acceleration sensor into a digital signal and supplies the digital signal to the activation determination unit. This is effective in reducing costs.

In the present invention, the start determination means compares the threshold value selected by the threshold value selection means with the lateral acceleration digitized and supplied from the A / D conversion means, The side airbag is deployed when the acceleration exceeds the threshold. According to the configuration of the present invention, communication is performed between the A / D conversion means and the activation determination means using a digital signal as a medium. For this reason, these two components can be spaced apart without considering the influence of noise. If the A / D conversion means and the activation determination means can be arranged separately, the longitudinal acceleration sensor can be arranged at a position separated from the lateral acceleration sensor. According to such a configuration, the longitudinal acceleration sensor, which is a component of the characteristic value detecting means, can be shared by a sensor mounted for another different purpose.

According to a fourth aspect of the present invention, in the side airbag starting apparatus according to the first aspect, the characteristic value detecting means detects a longitudinal acceleration acting on the vehicle, A side airbag activation device including: a speed change amount calculating unit that calculates a speed change amount of the vehicle obtained by integrating the longitudinal acceleration as the characteristic value is effective in improving responsiveness. .

In the present invention, the speed change amount calculating means includes:
The speed change amount of the vehicle is calculated by integrating the detection values of the longitudinal acceleration sensor. When energy is input in front of the vehicle, the speed of the vehicle is reduced due to the energy.
At this time, since the energy is not directly input to the occupant, a relative speed is generated between the vehicle and the occupant. This relative speed can be obtained by integrating the negative acceleration acting on the vehicle, that is, the deceleration. Further, the forward movement amount of the occupant with respect to the seat can be obtained by further integrating the relative speed, that is, by integrating the negative acceleration acting on the vehicle twice. As described above, in order to accurately determine the amount of forward movement of the occupant with respect to the seat, it is necessary to integrate the acceleration acting on the vehicle twice.

Incidentally, the value obtained by integrating the acceleration acting on the vehicle once, that is, the speed change amount of the vehicle is strictly different from the forward movement amount of the occupant, but has a high correlation with the forward movement amount of the occupant. Value. For this reason, the speed change amount of the vehicle can be used as a characteristic value of the forward movement amount of the occupant. When the value is used as the characteristic value as in the present invention, the calculation load for calculating the forward movement amount of the occupant can be reduced without impairing the control accuracy.

[0022]

FIG. 1 is an overall configuration diagram of an airbag system according to one embodiment of the present invention. The airbag system shown in FIG. 1 is mounted on a vehicle 10. The vehicle 10 includes left and right front wheels FL and FR and left and right rear wheels RL and RR.
It has.

The airbag system shown in FIG. 1 includes a driver seat airbag 12 and a passenger seat airbag 14. Hereinafter, these are collectively referred to as front airbags 12, 14. The driver's seat airbag 12 is housed in the center of the steering wheel 16. On the other hand, the passenger airbag 14 is housed inside the dashboard.

The vehicle 10 has a front airbag electronic control unit 18 (hereinafter referred to as a front ECU 18).
Is installed. The front ECU 18 includes the vehicle 10
And a longitudinal acceleration sensor for detecting longitudinal acceleration acting on the vehicle. Front airbags 12, 14
When the deceleration exceeding a predetermined value is detected by the front ECU 18, the steering wheel 1
6 and between the driver's seat 20 or between the dashboard and the passenger seat 22.

A side airbag 24 is housed in the backrest of the driver's seat 20. Similarly, a side airbag 26 is stored in the backrest of the passenger seat 22. Inside the center pillar provided on the right side of the vehicle 10,
A right side airbag electronic control unit 28 (hereinafter, referred to as right side ECU 28) is housed. On the other hand, an electronic control unit 30 for a left side airbag (hereinafter, referred to as a left side ECU 30) is accommodated inside a center pillar provided on the left side surface of the vehicle 10.

Right side ECU 28 and left side ECU
30, the lateral acceleration acting on the vehicle 10
Specifically, a lateral acceleration sensor for detecting a lateral acceleration acting on the center pillar on the right side surface or a lateral acceleration acting on the center pillar on the left side surface is incorporated. When the left side lateral acceleration exceeding a predetermined value is detected by the right side ECU 28, the side airbag 24 moves forward from the side of the driver's seat 20 to a position between the driver's seat 20 and the door of the vehicle 10. It is developed so as to extend by a predetermined length. On the other hand, when the left side ECU 30 detects a rightward lateral acceleration exceeding a predetermined value, the side airbag 26 moves forward from the side of the passenger seat 22 to the front of the passenger seat 22 and the door of the vehicle 10. It is developed so as to extend by a predetermined length between them.

The right side ECU 28 and the left side E
The CU 30 is a main part of the system according to the present embodiment. The structure of the right side ECU 28 and the structure of the left side ECU 30 will be described later in detail with reference to FIG. FIG. 2 shows a side view of the driver's seat 20. FIG. 2 shows the side airbag 24.
Indicates a state in which it is expanded. As described above, the side airbag 24 extends from the backrest of the driver's seat 20 forward by a predetermined length. The figure denoted by reference numeral 32 in FIG. 2 indicates a state of the driver sitting in the driver's seat 20 in a normal posture. As shown in FIG.
Is designed to extend to the side when the driver is deployed when the driver is seated in the driver's seat 20 in a normal posture.

When a large amount of energy is input from the front of the vehicle 10 while the vehicle 10 is running, the vehicle 10 is decelerated. Energy input to the vehicle 10 does not directly affect the driver of the vehicle 10. For this reason, the driver does not experience a deceleration that is large enough to occur in the vehicle 10. as a result,
When a large amount of energy is input from the front of the vehicle 10, the driver sitting in the driver's seat 20 in an appropriate posture moves relative to the driver's seat 20 forward.

In FIG. 2, the figure denoted by reference numeral 34 indicates a state in which the driver has moved forward with respect to the driver's seat 20 beyond the distance where the side airbag 24 extends. The side airbag 24 exhibits an effect by extending to the side of the driver. Therefore, when the driver is moving to the state indicated by reference numeral 34 in FIG. 2, even if the side airbag 24 is deployed, a great effect cannot be obtained.
For this reason, in such a situation, it is appropriate not to unnecessarily deploy the side airbag 24 from the viewpoint of reducing the repair cost of the vehicle 10.

FIG. 3 is a time chart realized when energy is input from a position offset laterally from the central axis of the vehicle 10, that is, when energy is offset input to the vehicle 10. FIG. 3 (A)
After the energy is offset-input at time t ₀ ,
Shows the change in the longitudinal acceleration G _X generated in the vehicle 10. When energy is offset input to the vehicle 10, then, a large longitudinal acceleration G _X is generated in the vehicle 10. TH _X shown in FIG. 3 (A) is a development threshold front air bags 12 and 14. As shown in FIG. 3A, when an energy offset input occurs, the longitudinal acceleration G _X reaches the threshold value TH _X a short time after time t ₀ .

FIG. 3B shows the front airbag 12,
14 shows the result of the startup determination of FIG. Front airbag 1
2,14 is activated by the longitudinal acceleration G _X reaches the threshold TH _X. Therefore, the front airbags 12 and 14, the longitudinal acceleration G _X is the threshold value TH
It is developed after time t _{1 when X} is reached.

FIG. 3C shows a change in the lateral acceleration G _Y detected by the right side ECU 28. Vehicle 10
When energy is offset input to
The vehicle 10 lateral acceleration G _Y is generated. The lateral acceleration G _Y is, as shown in FIG.
_It does not rise as sharply as _X and shows a relatively gradual rise. Figure 3 (C) TH _Y shown in the side air bag 2
4 shows an example of a development threshold value of 4. FIG. 3C shows the time t
_2, lateral acceleration G _Y represents a state in which the threshold is reached TH _Y.

FIG. 3D shows the result of the activation determination of the side airbag 24. Side air bags 24, lateral acceleration G _Y detected by the right side ECU28 is activated by reaching the threshold TH _Y. Therefore, lateral acceleration G _Y detected by the right ECU28 is, when the time t ₂ as shown in FIG. 3 reaches the threshold TH _Y, then the side airbag 24 is to be deployed.

When the energy is offset-input to the vehicle 10, the speed of the vehicle 10 is greatly reduced thereafter. Therefore, in the situation shown in FIG. 3, after time t ₀ , the driver of the vehicle 10 moves forward with respect to the driver's seat 20. As a result, the time point of time t ₂ when the activation determination of the side air bag 24 is made, a large forward displacement amount occurs in the driver. As described above, when the driver of the vehicle 10 is moving largely forward with respect to the driver's seat 20, the side airbag 24 should not be unnecessarily deployed. Therefore, in this case, it is not necessarily appropriate to deploying the side air bag 24 at time t _2.

The deployment of the side airbag 24 at the time t ₂ is performed, for example, at the time t ₁ by the front airbags 12 and 14.
After activation determination of is made, it can be prevented by prohibiting the deployment of the side air bag 24 for a predetermined time T _1. Therefore, if such a prohibition process is executed in the right side ECU 28 and the left side ECU 30, it is possible to prevent the side airbags 24, 26 from being unnecessarily deployed when the energy is offset input.

FIG. 4 is a diagram for explaining a process in which energy is input to the vehicle 10 in a complex manner. FIG. 4 (A)
Shows a state in which the vehicle 10 is traveling toward the on-road object 36 and another vehicle 38 is traveling from the side of the vehicle 10 toward the on-road object 36. FIG.
(B) shows a state in which the front surface of the vehicle 10 has reached the on-road object 38 after the state shown in FIG. FIG. 4C shows a state in which the front surface of the vehicle 38 has reached the side surface of the vehicle 10 after the state shown in FIG. 4B.

In the process of realizing the state shown in FIG. 4 (C), energy is first input to the vehicle 10 from the front, and then after a short time, energy is input from the side. In such a case, when the energy is input to the vehicle 10 from the front, the front airbag 1
It is appropriate to deploy the side airbags 24 when the energy is input to the vehicle 10 from the side while deploying the side airbags 24.

[0038] In contrast, as described above, the front airbags 12 and 14 and to prohibit deployment of the side air bag 24 and 26 for a predetermined time T ₁ after being deployed, the side surface of the vehicle 10 When the energy is input, the side airbag 24 cannot be deployed. Therefore, in consideration of the compound input of energy, the method of prohibiting useless deployment of the side airbags 24 and 26 by providing an operation prohibition period is the side airbag 2.
It is not necessarily the most suitable method for the activation control of 4, 26.

The system of this embodiment prevents the side airbags 24, 26 from being unnecessarily deployed when the energy is offset-input, and the side airbags 24, 26 when the energy is compositely input. Is characterized in that it can be developed. Further, the system of the present embodiment
When the energy is compounded, the side airbag 2
Only if deploying 4,26 is effective,
It has a characteristic in that it is developed.

FIG. 5 shows the forward movement S of the occupant with respect to the driver's seat 20 or the passenger's seat 22 and the side airbags 24 and 2.
6 shows the relationship with the magnitude of the effect obtained by developing No. 6. As described with reference to FIG. 2, the effect of the side airbags 24 and 26 decreases as the occupant's forward movement amount S increases. Therefore, the necessity of deploying the side airbags 24 and 26 depends on the forward movement amount S of the occupant.
The larger is the smaller.

FIG. 6 shows the magnitude of the energy E _Y input from the side to the vehicle 10 and the side airbag 24,
26 shows the relationship with the magnitude of the effect obtained by developing 26. In the vehicle 10, as the energy E _Y inputted to the side is large, the side air bag 24,
By deploying 26, a great effect can be obtained.
Therefore, the need for deployment of the side air bag 24 and 26, as energy E _Y is large, i.e., the larger the lateral acceleration G _Y is large.

In the system of the present embodiment, the energy is compounded based on the forward movement amount S of the occupant and the lateral acceleration G _Y in consideration of the characteristics shown in FIG. 5 and the characteristics shown in FIG. So that the optimal state is formed when
The activation of the side airbags 24 and 26 is determined.

FIG. 7 shows a right side E which is a main part of this embodiment.
2 shows a block diagram of the CU 28. FIG. The left side ECU
30 is substantially the same as the right side ECU 28 in the configuration, and therefore, only the configuration of the right side ECU 28 will be described here. The right side ECU 28, longitudinal acceleration sensor 4 for detecting a longitudinal acceleration G _X that acts on the vehicle 10
0 is provided. The longitudinal acceleration sensor 40 is a vehicle 1
It generates an analog signal V _X in accordance with the longitudinal acceleration G _X that acts on 0. Output signal V _X of longitudinal acceleration sensor 40
Is supplied to the movement amount calculation circuit 42.

[0044] When the energy to the vehicle 10 has been entered, the amount S of the occupant against the seat moves forward can be calculated based on the longitudinal acceleration G _X generated in the vehicle 10. Hereinafter, a method of calculating the forward movement amount S will be described with reference to FIG. FIG. 8A shows a state in which the front surface of the vehicle 10 traveling at the speed V ₀ has reached the road object 44. After the state shown in FIG. 8A is formed, an acceleration Gx in which the rearward direction of the vehicle is the forward direction is generated in the vehicle 10 thereafter. For this reason, the speed of the vehicle 10 changes to the speed V represented by the following equation.

V = V ₀ −∫G _X dt (1) On the other hand, the energy input to the vehicle 10 does not directly act on the occupant of the vehicle 10. Therefore, the moving velocity V of the passenger remains unchanged initial velocity V _0. Therefore, when energy is input to the front of the vehicle 10, a relative speed ΔV represented by “ΔV = ∫G _X dt” is generated between the vehicle 10 and the occupant.

FIGS. 8B, 8C and 8D
Is the longitudinal acceleration G _X that occurs when energy is input to the front of the vehicle 10, and its one-time integration value ∫G _X
4 shows a time chart of dt and its twice-integrated value ΔG _X dt. The one-time integral value ∫G _X dt of the longitudinal acceleration G _X shown in FIG. 8C is the amount of speed change of the vehicle 10 and
The relative speed ΔV generated between the vehicle 10 and the occupant as described above
Becomes Then, the longitudinal acceleration G _X shown in FIG.
Double integration value ∬G _X dt of, the forward movement amount S of the occupant relative to the seat. Therefore, in the system of this embodiment,
The signal V _X which is output from the longitudinal acceleration sensor 40 by integrating twice, it is possible to determine the characteristic values of the occupant of the forward movement amount S.

The amount of movement connected to the longitudinal acceleration sensor 40
The arithmetic circuit 42 outputs the analog signal V_XIntegrate twice
The characteristic value S of the movement amount S^*= ∬V_XFind dt. Characteristic
Value S ^*Can be treated as substantially the forward movement amount S.
Value. The movement amount calculation circuit 42 outputs the analog signal V_X
Is processed without digitizing, and
Sex value S^*Is output as an analog signal. Movement amount calculation circuit 4
Characteristic value S output from 2^*Is a threshold setting circuit 46
Supplied to

FIG. 9 shows an example of a map used for the threshold value setting circuit 46. The threshold setting circuit 46 is configured as shown in FIG.
The deployment threshold V _THY of the side airbag 24 is set based on the characteristic value S ^* with reference to the map shown in FIG. The map shown in FIG. 9 is set such that the deployment threshold value V _THY increases as the occupant's forward movement amount S increases.

The threshold value setting circuit 46 processes the characteristic value S ^* supplied from the movement amount calculating circuit 42 without digitizing it, and _converts the developed threshold value V _THY set based on the map shown in FIG. Output as an analog signal. The developed threshold value V _THY output from the threshold value setting circuit 46 is supplied to the activation determination circuit 48.

The right side ECU 28 has a built-in lateral acceleration sensor 50 for detecting a lateral acceleration G _Y acting on the vehicle 10. Lateral acceleration sensor 50 generates an analog signal V _Y corresponding to the lateral acceleration G _Y acting on the vehicle 10. The output signal V _Y generated by the lateral acceleration sensor 50 is based on the developed threshold V _{TH Y} issued from the threshold setting circuit 46.
At the same time, it is supplied to the activation determination circuit 48.

The activation determination circuit 48 compares the magnitude relationship between the output signal V _Y and the development threshold V _THY . As a result, V
_{If Y} ≧ V _THY is satisfied, it is determined that the lateral acceleration G _Y should be deployed side airbag 24 to the vehicle 10 occurs. On the other hand, if V _Y ≧ V _THY is not established, it is determined that the lateral acceleration G _Y for deploying the side airbag 24 with respect to the vehicle 10 has not occurred.

The drive circuit 52 is connected to the start determination circuit 48. The activation determination circuit 48 supplies a drive signal to the drive circuit 52 when determining that a situation in which the side airbag 24 should be deployed has occurred. The squib 54 is connected to the drive circuit 52. Squibb 5
Reference numeral 4 denotes an ignition device incorporated in the side airbag 24, and the side airbag 24 is deployed when a drive signal is supplied from a drive circuit 52.

The threshold value V for deployment of the side airbag 24
_{When THY} is set according to the map shown in FIG. 9 as a function of the movement amount S, it is possible to form a state in which the side airbag 24 is difficult to deploy as the forward movement amount S of the occupant increases, and to truly deploy the side airbag 24. Is required, the side airbag 24 can be appropriately deployed.
Therefore, according to the system of the present embodiment, when the forward movement amount S of the occupant is large, the side airbags 24 and 26 can be prevented from being unnecessarily deployed, and the vehicle 1
When a large energy E _Y is input to the 0 side,
Regardless of the magnitude of the movement amount S, the side airbags 24, 26
Can be expanded.

In the system of this embodiment, in order to accurately reflect the forward movement amount S of the occupant in the determination of the activation of the side airbag 24, a signal used for communication between the components of the right side ECU 28 is as follows. It is necessary to have high resolution. Therefore, it is necessary to generate a digital signal having a high resolution in order to perform communication between the components using digital signals and accurately reflect the forward movement amount S in the start determination.

However, in order to perform communication between components using a digital signal having a high resolution, sophisticated and complicated arithmetic processing is required. Therefore, if such a communication method is used, the side airbag 2
It is difficult to obtain high responsiveness regarding the start determination of No. 4. On the other hand, in the system of the present embodiment, the communication between the components is performed using an analog signal as a medium, and the activation determination of the side airbag 24 is performed by performing predetermined analog processing in each component. And

Analog signals are more susceptible to noise than digital signals. For this reason, if an analog signal is used for long-distance communication, the communication accuracy between the components tends to be impaired. However, in this embodiment,
Communication using an analog signal as a medium is performed by the right side ECU 28.
This is performed only between a plurality of components arranged in a position extremely close to each other in the inside or the left side ECU 30. Therefore, according to the system of the present embodiment, high responsiveness can be ensured with respect to the determination of the activation of the side airbag, and accurate activation determination can be performed without being affected by noise.

In the above description, the right side ECU 28 for judging the activation of the side airbag 24 has mainly been described. However, the right side ECU 30 for judging the activation of the side airbag 26 can also be used for the right side ECU 30. EC
The same effect as that of U28 can be obtained.

In the above embodiment, the longitudinal acceleration sensor 40 and the movement amount calculating circuit 42 correspond to the "characteristic value detecting means" according to the first embodiment, and the threshold setting circuit 46 corresponds to the "characteristic detecting means" according to the first embodiment. The threshold value setting means "
8 corresponds to the “start-up determination means” of the first aspect, and the movement amount calculation circuit 42 corresponds to the “characteristic value calculation means” of the second aspect.

In the above-described embodiment, the right side ECU 28 is constituted by a circuit for performing processing using an analog signal as a medium. However, the present invention is not limited to this. And a microcomputer which digitizes the output signal of the lateral acceleration sensor 50 and the output signal of the lateral acceleration sensor 50.
The CU 28 may be configured.

Next, a second embodiment of the present invention will be described with reference to FIG. System of the present embodiment, in the system shown in FIG 1, once the integrated value S ^** = ∫V _X dt of the signal V _X which is output from the longitudinal acceleration sensor 40, the occupant of the forward movement amount characteristic values of S This is realized by using

1 of the output signal V _X of the longitudinal acceleration sensor 40
Times the integral value S ^** = ∫V _X dt, after the energy begins to enter the front of the vehicle 10, a value corresponding to the speed variation ΔV occurring in the vehicle 10. As shown in FIGS. 8 (C) and 8 (D), after the energy starts to act on the vehicle 10, until the ΔV reaches the upper limit value, that is, until the vehicle 10 stops, the speed change amount A large correlation is observed between ΔV and the forward movement amount S. Therefore, once the integrated value S ^** = ∫V _X dt of the output signal V _X can be used sufficiently as the characteristic value of the forward movement amount S of the occupant.

[0062] system of the present embodiment, specifically, the movement amount calculating circuit 42 provided in the right side ECU28 and left side ECU30 (see FIG. 7), constituted by a circuit for calculating a single integral value of the signal V _X At the same time, the movement amount calculation circuit 42
The threshold value setting circuit 46 connected to the side airbags 24 and 26 sets the deployment threshold value V _THY of the side airbags 24 and 26 based on the map shown in FIG. The map shown in FIG. 10 is a map in which the deployment threshold value V _THY is determined in relation to the vehicle speed change amount ΔV so that the same deployment characteristics as those of the system of the first embodiment can be obtained.

According to the system of this embodiment, the calculation load of the characteristic value S ^** of the forward movement amount S can be reduced as compared with the system of the first embodiment. Therefore, according to the system of the present embodiment, the forward movement amount S can be reflected in the determination of the activation of the side airbags 24 and 26 as in the system of the first embodiment, and the system of the first embodiment can be used. Even better responsiveness can be realized.

In the above embodiment, the moving amount calculating circuit for calculating the one-time integral value of the longitudinal acceleration sensor 40 is:
This corresponds to "speed change amount calculating means". Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 11 is an overall configuration diagram of an airbag system according to a second embodiment of the present invention.
In FIG. 11, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

The system of the present embodiment includes a front ECU 6
0, right side ECU 62 and left side ECU 64
It has. The right side ECU 62 is housed in a right center pillar of the vehicle 10. Right side ECU 62
Provides a digital signal corresponding to the lateral acceleration G _Y generated in the right center pillar front ECU 60. On the other hand, the left side ECU 64 is housed in a left center pillar of the vehicle 10. Left ECU64 is output toward the digital signal to the front ECU60 in accordance with lateral acceleration G _Y generated in the left center pillar.

The front ECU 60 has a built-in longitudinal acceleration sensor for detecting the longitudinal acceleration occurring in the vehicle 10. Front ECU60, the detection value of the longitudinal acceleration sensor, and, based on the lateral acceleration G _Y supplied from the right side ECU62 and left side ECU 64, the deployment of the front air bag 12, 14 and side air bags 24 and 26 Control.

FIG. 12 is a block diagram showing the structure of the right side ECU 62 and the structure of the front ECU 60. The left side ECU 64 includes a right side EC
Since it is substantially the same as U62, its description is omitted here. In FIG. 12, the same components as those shown in FIG. 7 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

As shown in FIG. 12, the right side ECU 62
Has a lateral acceleration sensor 50. Lateral acceleration sensor 50 outputs an analog signal V _Y corresponding to the lateral acceleration G _Y generated in the vehicle 10. Analog signal V _Y outputted from the lateral acceleration sensor 50 is supplied to the A / D converter 66. The A / D converter 66 is a device that converts an analog signal supplied from the lateral acceleration sensor 50 into a digital signal.

FIG. 13 shows the relationship between the analog signal V _Y supplied to the A / D converter 66 and the threshold values V _{TH1 to} V _TH3 set in the A / D converter 66. As shown in FIG. 13, the A / D converter 66 has three different threshold values V.
_{TH1 to} V _TH3 are set. The A / D converter 66
Analog signal V supplied from lateral acceleration sensor 50
_Y is compared with three different threshold values V _{TH1 to} V _TH3, and a digital signal corresponding to the comparison result is output.

FIG. 14 shows a waveform of a digital signal output from the A / D converter. FIG. 14A shows that V _TH1 ≦
7 shows a code signal output from the A / D converter 66 when V _Y holds. FIG. 14B shows that V _TH2 ≦ V _Y <V
₇ shows a code signal output from the A / D converter 66 when _TH1 is satisfied. FIG. 14C shows that V _TH3 ≦ V
_The code signal output from the A / D converter 66 when _Y <V _TH2 holds. Thus, the A / D converter 6
6, depending on the value of the analog signal V _Y supplied from the lateral acceleration sensor 50, and outputs three digital signals having different duty ratios.

As shown in FIG. 12, the front ECU 60
Includes an activation determination circuit 68. Start-up determination circuit 68
Has the characteristic value S ^* = 演算 calculated by the movement amount calculation circuit 42.
G _X dt is supplied using an analog signal as a medium,
A digital signal output from the A / D converter 66 of the right side ECU 62 is supplied. The activation determination circuit 68 detects the forward movement amount of the occupant based on the characteristic value S ^* ,
Based on the digital signal supplied from the A / D converter 66 for detecting the level of the lateral acceleration G _Y occurring in the vehicle 10.

More specifically, the activation determination circuit 68 determines whether the A / D
When the code shown in FIG. 14A is supplied from the converter 66, the vehicle 10 receives the high-level lateral acceleration G
_{When Y} is generated, when the code shown in FIG. 14B is supplied, it is determined that middle level lateral acceleration G _Y is generated in the vehicle 10, and as shown in FIG. 14C. If the code is supplied to determine the lateral acceleration G _Y of the low level to the vehicle 10 has occurred.

FIG. 15 shows an example of a map used when the activation determination circuit 68 determines the activation of the side airbag 24. Note that the step-shaped broken line shown in FIG. 15 is a boundary line separating the deployed region and the non-deployed region of the side airbag 24. As shown in FIG. 15, the activation determination circuit 68
Forward movement amount S of the passenger is in the region less than a first predetermined value S _1, to deploy the side air bag 24 when the lateral acceleration above a low level of G _Y has occurred. In addition, the activation determination circuit 68 determines that the lateral acceleration G _Y at or above the middle level in a region where the forward movement amount S of the occupant is equal to or greater than the first predetermined value S ₁ and less than the second predetermined value S _2. Is deployed, the side airbag 24 is deployed. The activation decision circuit 68, in the region occupant forward movement amount S is the second predetermined value S ₂ or more, the side air bag 2 when horizontal or high-level direction acceleration G _Y is occurring
Expand 4

According to the above processing, the forward movement amount S of the occupant
As the size of the airbag becomes larger, it is possible to form a state in which the side airbag 24 is difficult to deploy, and when the deployment is truly required, the side airbag 24 can be appropriately deployed. Therefore, the system according to the present embodiment can also prevent the side airbags 24 and 26 from being unnecessarily deployed when the forward movement amount S is large, as in the first or second embodiment. When the large energy _EY is input to the side of the vehicle 10, the side airbags 24 and 26 can be deployed regardless of the magnitude of the movement amount S.

In the system of this embodiment, the characteristic value S ^* of the forward movement amount S of the occupant is calculated using the longitudinal acceleration sensor 60 built in the front ECU 60. The front ECU 60 is necessarily provided with the longitudinal acceleration sensor 40 in order to control the deployment of the front airbags 12 and 14. Therefore, the system of the present embodiment can be realized without adding a modified longitudinal acceleration sensor for obtaining the characteristic value S ^* of the forward movement amount S.
Therefore, according to the structure of the present embodiment, a system that can reflect the forward movement amount S in the activation determination of the side airbags 24 and 26 can be realized at low cost.

Further, as in the system of this embodiment, the lateral acceleration sensor 50 for detecting the lateral acceleration G _Y and the longitudinal acceleration sensor 40 for detecting the longitudinal acceleration G _X are spaced apart from each other. information about acceleration G _Y, and information related to the longitudinal acceleration G _X is, when used in one place, the detected value of at least one of an acceleration sensor, needs to be transmitted to the vicinity of the other acceleration sensor is there. In this case, if an analog signal is used as a transmission medium, accurate communication may not be performed due to the influence of noise.

On the other hand, in the system of this embodiment,
Communication from the right side ECU 62 and the left side ECU 64 to the front ECU 60 is performed using digital signals as a medium. Therefore, according to the system of the present embodiment, the lateral acceleration sensor 50 and the longitudinal acceleration sensor 40
In spite of being located apart from each other, accurate control can be realized without being affected by noise.

In the above embodiment, the longitudinal acceleration sensor 40 and the movement amount calculating circuit 42 correspond to the "characteristic value detecting means" according to the first aspect, and the start-up determination circuit 68 corresponds to the "characteristic value detecting means" according to the first aspect. The movement amount calculation circuit 42 corresponds to the “characteristic value calculation means” according to the second aspect. Further, in the above embodiment, the activation determination circuit 68 performs the activation determination based on the map shown in FIG. 15, thereby realizing the “threshold selection means” according to the third aspect.

By the way, in the above embodiment, S ^* = ∬V _X dt corresponding to twice integral value of longitudinal acceleration G _X
And although the characteristic values of the forward movement amount S, the present invention is not limited thereto, as in the second embodiment described above, corresponding to one integrated value of the longitudinal acceleration G _X S ^** = ∫V _X dt may be used as characteristic values of the forward movement amount S of.

[0080]

As described above, according to the first aspect of the present invention, when the occupant is moving forward with respect to the seat,
In addition to preventing the side airbags from being unnecessarily deployed, even when energy is input to the vehicle from the front and then energy is input to the side of the vehicle after a short time, The side airbag can be appropriately deployed as needed.

According to the second aspect of the present invention, communication between the components can be performed using an analog signal as a medium without being affected by noise. Therefore, according to the present invention, it is possible to make a start determination according to the forward movement amount of the occupant with high responsiveness.

According to the third aspect of the present invention, the characteristic value corresponding to the forward movement amount of the occupant can be obtained by using the longitudinal acceleration sensor mounted for another purpose. For this reason,
ADVANTAGE OF THE INVENTION According to this invention, the activation device of the side airbag which changes an expansion threshold value according to the occupant's forward movement amount can be implement | achieved at low cost.

According to the fourth aspect of the invention, the amount of change in the speed of the vehicle is used as the characteristic value of the amount of forward movement of the occupant with respect to the seat, so that the calculation load can be reduced without impairing the control system. it can. For this reason, according to the present invention, high responsiveness can be obtained without any adverse effect compared to a case where the forward movement amount of the occupant is accurately calculated.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an airbag system according to an embodiment of the present invention.

FIG. 2 is a diagram for explaining a relative positional relationship between an occupant of the vehicle and a side airbag.

[3] FIG. 3 (A) is an example of a time chart of the longitudinal acceleration G _X is detected on the vehicle. FIG. 3B is an example of a time chart of the result of the determination of the activation of the front airbag. FIG. 3 (C) is an example of a time chart of the lateral acceleration G _Y detected on the vehicle. FIG. 3D is an example of a time chart of the result of the determination of the activation of the side airbag.

FIG. 4A is a diagram (part 1) illustrating a vehicle, an object installed on a road, and another vehicle in a plan view. FIG. 4 (B)
FIG. 2 is a diagram (part 2) illustrating a vehicle, a road-installed object, and another vehicle in a plan view. FIG. 4C is a diagram (part 3) illustrating the vehicle, the on-road object, and another vehicle in plan view.

FIG. 5 is a diagram illustrating a relationship between an amount of forward movement of an occupant and a magnitude of an effect obtained by deploying a side airbag.

FIG. 6 is a diagram showing the relationship between the magnitude of energy input to the side of the vehicle and the magnitude of the effect obtained by deploying the side airbag.

FIG. 7 is a right side EC used in the first embodiment of the present invention.
It is a block diagram of U.

FIG. 8A is a diagram showing a vehicle and a road-installed object in a side view. Figure 8 (B) is a time chart of the longitudinal acceleration G _X is detected on the vehicle. Figure 8 (C) is a time chart of one integral value of the longitudinal acceleration G _X is detected on the vehicle. Figure 8 (D) is a time chart of the two integral value of the longitudinal acceleration G _X is detected on the vehicle.

FIG. 9 is an example of a map used for determining a deployment threshold value of the side airbag in the first embodiment of the present invention.

FIG. 10 is an example of a map used for determining a deployment threshold value of a side airbag in the second embodiment of the present invention.

FIG. 11 is an overall configuration diagram of an airbag system according to a third embodiment of the present invention.

FIG. 12 shows a right side E used in the third embodiment of the present invention.
FIG. 2 is a block diagram of a CU and a front ECU.

FIG. 13 shows a lateral acceleration G according to a third embodiment of the present invention.
FIG. 3 is a diagram for explaining a method used when _performing A / D conversion on _Y.

FIG. 14A is a diagram showing a right side E when the lateral acceleration G _Y is at a high level in the third embodiment of the present invention.
7 is a waveform of a code signal transmitted from the CU to the front ECU. FIG. 14B shows the third embodiment of the present invention, in which the lateral acceleration _GY is at the middle level and the right side E
7 is a waveform of a code signal transmitted from the CU to the front ECU. FIG. 14C shows the right side EC when the lateral acceleration _GY is at a low level in the third embodiment of the present invention.
7 is a waveform of a code signal transmitted from U to the front ECU.

FIG. 15 is an example of a map used to determine the activation of the side airbag in the third embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 10 Vehicle 18, 60 Electronic control unit for front airbag (front ECU) 20 Driver's seat 22 Passenger's seat 24, 26 Side airbag 28, 62 Right side ECU 30, 64 Left side ECU 40 Front / rear acceleration sensor 42 Moving amount calculation circuit 46 Threshold setting circuit 48 Start determination circuit 50 Lateral acceleration sensor 66 A / D converter S Forward movement amount of occupant S ^* , S ^** Characteristic value of forward movement amount ΔV Vehicle speed change amount

Claims (4)

[Claims] 1. A characteristic value detecting means for detecting a characteristic value of a relative forward movement amount of an occupant with respect to a seat; a lateral acceleration sensor for detecting a lateral acceleration acting on a vehicle; and an occupant based on the characteristic value. Threshold value setting means for setting the deployment threshold value of the side airbag to a larger value as the amount of forward movement of the side airbag increases, and when the detection value of the lateral acceleration sensor is equal to or greater than the deployment threshold value, And a start-judgment means for developing the side airbag. 2. The side airbag activation device according to claim 1, wherein the characteristic value detecting unit detects a longitudinal acceleration acting on the vehicle in a longitudinal direction and a characteristic value based on the longitudinal acceleration. And a characteristic value calculating means for calculating, wherein the longitudinal acceleration sensor, the characteristic value calculating means, the threshold value setting means, the lateral acceleration sensor, and the activation determining means are not affected by noise. A side airbag activation device which is arranged close enough to communicate with each other via an analog signal. 3. The side airbag activation device according to claim 1, wherein the threshold value setting unit is configured to determine a threshold value according to an amount of forward movement of the occupant from a plurality of threshold values based on the characteristic value. A side airbag activation device comprising: threshold selection means for selecting a value; and A / D conversion means for converting a detection value of the lateral acceleration sensor into a digital signal and supplying the digital signal to the activation determination means. 4. The side airbag activation device according to claim 1, wherein the characteristic value detection unit is obtained by integrating a longitudinal acceleration sensor that detects longitudinal acceleration acting on the vehicle and the longitudinal acceleration. A speed change amount calculating means for calculating a speed change amount of the vehicle as the characteristic value.