JPH11334520A - Air bag device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately control the inner pressure of an air bag by changing the amount of gas exhausted out of a vent hole during deployment of the air bag. SOLUTION: A control valve 30 formed by adhering a plate piezoelectric element 31 to a metal protector 32, a vent hole 29 opened/closed by the control valve 30 and an inner pressure detecting means 35d for detecting the inner pressure of an air bag 21 are provided on a retainer 19 for supporting an inflator 20 and an air bag 21 for an air bag device. The piezoelectric element 31 closing the vent hole 29 during no power supply is curved with power supply to open the vent hole 29 for exhausting gas in the air bag 21 to the outside. The opening of the vent hole 29 is feedback controlled in accordance with the inner pressure of the air bag detected by the inner pressure detecting means 35d so that the change in inner pressure of the air bag with the passage of a time can correspond to an preset inner pressure pattern.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag in which an inflator is housed inside a retainer to which the periphery of an opening of a folded airbag is fixed, and which is inflated by gas generated by the inflator upon collision of a vehicle. The present invention relates to an airbag device for restraining an occupant.

[0002]

2. Description of the Related Art In a conventional airbag apparatus, a vent hole is provided in an airbag inflated by gas generated by an inflator, and a part of the gas is discharged from the vent hole to control the internal pressure of the airbag. In such an airbag device, by closing the vent hole with a thin film, the airbag is quickly inflated in the early stage of deployment, and when the deployment is completed and the internal pressure of the airbag increases, the thin film is broken, and the vent hole is broken. That exhaust gas from the vehicle and restrain the occupant softly (Japanese Utility Model 5-62)
No. 06).

Further, two inflators are provided in the airbag device, and when no occupant is present near the airbag device, both of the two inflators are ignited, and the occupant is present near the airbag device. In such a case, a method has been proposed in which the deployment speed and the internal pressure of the airbag are controlled in accordance with the position of the occupant by igniting only one inflator (see JP-A-9-301115).

[0004]

However, the structure disclosed in Japanese Utility Model Publication No. 5-6206 is liable to cause variation in the pressure at which the thin film breaks, so that when the internal pressure of the airbag reaches a predetermined value. In addition, it is difficult to precisely open the vent hole, and it is difficult to precisely control the internal pressure because the vent hole once opened cannot be closed again. In addition, Japanese Patent Application Laid-Open No. 9-301115
Japanese Patent Application Laid-Open Publication No. H11-146556 requires not only two inflators but also an increase in the number of parts, which causes a cost increase. There was a problem that control was difficult.

The present invention has been made in view of the above circumstances, and has as its object to accurately control the internal pressure of an airbag by changing the amount of gas discharged from a vent hole when the airbag is deployed.

[0006]

According to one aspect of the present invention, an inflator is housed inside a retainer to which a periphery of an opening of a folded airbag is fixed. In an airbag device that expands an airbag inflated by gas generated by the inflator at the time of collision and restrains an occupant, a vent hole formed in the retainer, and a control valve that is operated by an actuator to open and close the vent hole. An internal pressure detecting means for detecting the internal pressure of the airbag, and a control means for performing feedback control of the opening of the vent hole so that the internal pressure of the airbag detected by the internal pressure detecting means matches a preset internal pressure pattern. It is characterized by having. According to the above configuration, the amount of gas discharged from the vent hole is changed by the control means driving the control valve to open and close by the actuator to change the opening degree of the vent hole in accordance with the internal pressure of the air bag detected by the internal pressure detecting means. Is arbitrarily changed to match the internal pressure of the airbag with a preset internal pressure pattern, so that the internal pressure of the airbag can be controlled to an optimal level to enhance the occupant restraint performance.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, occupant state detecting means for detecting an occupant state is provided, and the control means detects the occupant state by the occupant state detecting means. The internal pressure pattern is changed according to the state of the occupant.

According to the above configuration, the opening degree of the vent hole can be controlled so that the airbag internal pressure according to the state of the occupant can be obtained. The magnitude of the airbag internal pressure can be set optimally.

According to a third aspect of the present invention, in addition to the configuration of the first aspect, a vehicle speed detecting means for detecting a vehicle speed is provided, and the control means responds to the vehicle speed detected by the vehicle speed detecting means. The internal pressure pattern is changed.

[0010] According to the above configuration, the opening of the vent hole can be controlled so as to obtain the airbag internal pressure according to the vehicle speed. Therefore, the magnitude of the airbag internal pressure is optimally set in accordance with the vehicle speed. can do.

According to a fourth aspect of the present invention, in addition to the first aspect, the actuator is a piezoelectric element.

[0012] According to the above configuration, by forming the actuator by a piezoelectric element, the vent hole can be opened and closed at a low cost with a simple structure having a smaller number of parts than other actuators such as a motor and a solenoid. Can be.

According to a fifth aspect of the present invention, in addition to the configuration of the fourth aspect, the actuator is a plate-shaped piezoelectric element arranged to cover the vent hole and one end fixed to the retainer. There is a feature.

According to the above configuration, by forming the actuator with the plate-like piezoelectric element, not only the structure of the actuator becomes extremely simple, but also the piezoelectric element itself can be used as a valve body, It is possible to further reduce the number of points and cost.

According to a sixth aspect of the present invention, in addition to the first aspect, the retainer has a plurality of vent holes, and the control valve has a plurality of openings respectively corresponding to the plurality of vent holes. A valve plate is formed, and the actuator slides the valve plate along the retainer so that the plurality of openings face the plurality of vent holes.

According to the above configuration, by combining a plurality of vent holes formed in the retainer and a plurality of openings formed in the valve plate, the opening degree of the vent hole can be fully closed by only slightly moving the valve plate. It is possible to change from the state to the fully open state, so that downsizing of the actuator and improvement of responsiveness are achieved at the same time.

According to a seventh aspect of the present invention, in addition to the configuration of the sixth aspect, the plurality of vent holes are arranged in a circumferential direction, and the valve plate is driven to rotate reciprocally by the actuator. It is characterized by the following.

According to the above configuration, a plurality of vent holes arranged in the circumferential direction are opened and closed by the valve plate reciprocatingly driven by the actuator, so that a rotary output actuator such as a motor can be easily applied. it can.

According to an eighth aspect of the present invention, in addition to the configuration of the sixth aspect, the plurality of vent holes are arranged in a linear direction, and the valve plate is reciprocated linearly driven by the actuator. It is characterized by.

According to the above construction, a plurality of vent holes arranged in a linear direction are opened and closed by a valve plate which is reciprocally driven linearly by an actuator. Therefore, a linear output actuator such as a linear solenoid or a laminated piezoelectric element can be used. Can be easily applied.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described based on embodiments of the present invention shown in the accompanying drawings.

1 to 26 show an embodiment of the present invention. FIG. 1 is a perspective view of a front portion of a vehicle compartment of an automobile, FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1, and FIG. FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 3, FIG. 5 is an exploded perspective view of the driver airbag device, and FIG. 6 is a modified example of the driver airbag device. FIG. 7 is an enlarged sectional view taken along line 7-7 of FIG. 6, FIG. 8 is an enlarged sectional view taken along line 8-8 of FIG. 1, and FIG. 9 is a sectional view taken along line 9-9 of FIG. FIG. 10 and FIG.
FIG. 11 is an exploded perspective view of the passenger airbag device, FIG. 12 is a view corresponding to FIG. 9, and FIG. 13 is a first modified example of the passenger airbag device. 12 of 1
FIG. 14 is a sectional view taken along line 3-13, FIG. 14 is a sectional view taken along line 14-14 in FIG. 12, FIG. 15 shows a second modification of the airbag device for the passenger seat, and corresponds to FIG. 16-1
6, FIG. 17 is a sectional view taken along line 17-17 of FIG. 15, FIG. 18 is an enlarged sectional view taken along line 18-18 of FIG. 1, and FIG.
FIG. 20 is a sectional view taken along line 20-20 of FIG. 19, FIG. 21 is a sectional view taken along line 21-21 of FIG. 19, FIG. 22 is a sectional view taken along line 22-22 of FIG. FIG. 24 is a block diagram showing a control system of a hole opening degree, FIG. 24 is a diagram showing an example of a change in a target internal pressure pattern depending on an occupant state, FIG. 25 is a diagram showing an example of a change in a target internal pressure pattern depending on a vehicle speed, and FIG.
FIG. 3 is an explanatory diagram of feedback control of a vent hole opening degree.

As shown in FIG. 1, an airbag device Rd for a driver's seat is provided at the center of a steering wheel 2 disposed in front of a driver's seat 1, and a dashboard disposed in front of a passenger's seat 3. An airbag device Rp for a passenger seat is provided on the upper part of the vehicle seat 4, and side collision airbag devices Rs, Rs are provided inside the driver seat 1 and the seatbacks 5, 5 of the passenger seat.

Next, the structure of the driver's seat airbag device Rd will be described with reference to FIGS.

The steering wheel 2 is fitted to the rear end of the steering shaft 11 such that it cannot rotate relative to each other.
2, a steering boss 13 fixed at 2, an annular wheel rim 14 arranged so as to surround the steering boss 13, a front cover 15 fixed to the steering boss 13, and connected to the front cover 15. A rear cover 16 and a plurality of spokes 17 for connecting the front cover 15 to the wheel rim 14 are provided.
The airbag module 18 is housed in the space defined by.

The airbag module 18 includes a retainer 19 for supporting the airbag module on the inner surface of the rear cover 16, an inflator 20 for generating high-pressure gas, and an inflator 2.
The airbag 21 is inflated by the generated high-pressure gas. Rivet outer periphery of the plurality of the mounting flange 16 ₁ formed integrally on the inner periphery of the mounting flange 19 ₁ rear cover 16 which is formed integrally of the retainer 19 22
, And the peripheral edge of the opening of the airbag 21 and the ring-shaped holder 23 are overlapped and fastened together to the retainer 19 with a plurality of bolts 24. The inflator 20 filled with the granular gas generating agents 25.
1 and is retained by a plurality of bolts 26.
9 is fixed. The igniting agent 2 is provided inside the inflator 20.
7 is disposed, and the tip of an igniter 28 extending inside the inflator 20 faces the igniting agent 27.

The retainer 19 facing the inside of the airbag 21
Are formed in series. The control valve 30 for controlling the opening degree of the vent holes 29 is formed by bonding a strip-shaped piezoelectric element 31 to a protector 32 of the same shape made of a metal plate, and one side surface covers the vent holes 29. As shown in FIG.
At 33, it is fixed to the retainer 19. The fragile and easily breakable piezoelectric element 31 is reinforced by being bonded to the protector 32. The piezoelectric element 31 constitutes the actuator of the present invention.

As shown in FIG. 23, the airbag deployment control device 34 constituting the control means of the present invention includes an acceleration detection means 35a for detecting the acceleration at the time of collision of the vehicle, and the weight, physique, and sitting posture of the occupant. Occupant state detecting means 35b for detecting the occupant state such as the vehicle speed, and vehicle speed detecting means 35c for detecting the vehicle speed
And an internal pressure detecting means 35 for detecting the internal pressure of the airbag 21.
d is connected. The occupant state detecting means 35b is provided on the seat cushion to identify the adult and the child by detecting the weight of the occupant, or is configured to identify the adult and the child by detecting the sitting height of the occupant by infrared rays. You. The internal pressure detecting means 35d is constituted by a normal pressure sensor, and is provided in the retainer 19 so that the detecting portion faces the internal space of the airbag 21.

The airbag deployment control device 34 energizes the igniter 28 to ignite the inflator 20 when acceleration equal to or greater than a predetermined value is detected at the time of a vehicle collision.
There airbag 21 which is inflated with a gas generated expands into the passenger compartment by breaking a thin tear line 16 ₂ formed H-shaped in the rear cover 16. At this time, the airbag deployment control device 34 controls the energization of the control valve 30 to the piezoelectric element 31 based on a signal from the occupant state detecting means 35b or the vehicle speed detecting means 35c, and changes the opening of the vent holes 29. That is, when the piezoelectric element 31 is not energized,
As shown in FIG. 4A, the control valve 30 extends linearly, closes the vent holes 29, and when the piezoelectric element 31 is energized, as shown in FIG.
Are bent to open the vent holes 29. In this way, the opening degree of the vent holes 29 can be controlled precisely and steplessly by an extremely simple structure in which the plate-shaped piezoelectric element 31 covering the vent holes 29 is simply energized and curved.

At this time, a plurality of internal pressure patterns of the airbag 21, that is, changes in the internal pressure of the airbag 21 with the passage of time are stored in advance as a map, and the airbag deployment control device 34 selects one of the plurality of internal pressure patterns. The control valve 30 is controlled by selecting a predetermined internal pressure pattern.
Further, feedback control based on the airbag internal pressure detected by the internal pressure detection means 35d is performed so that the actual airbag internal pressure matches the internal pressure pattern stored in the map. The specific contents of the opening control of the control valve 30 will be described later in detail.

FIGS. 6 and 7 show a modification of the airbag device Rd for the driver's seat, in which the structure of the control valve 30 is different from that described with reference to FIGS.

The control valve 30 of this modification opens and closes the vent holes 29 arranged annularly in the retainer 19, and has the same number and the same number of openings 36 _{1 as the} vent holes 29.
, And an ultrasonic motor 37 that rotationally drives the valve plate 36. When the valve plate 36 is at the position shown in FIG. 7A, the vent holes 29 are closed by the valve plate 36, and when the valve plate 36 is at the position shown in FIG. _The vent holes 29 are opened by ₁ .

As described above, the opening degree of the plurality of annularly arranged vent holes 29 is controlled by rotating the valve plate 36 having the plurality of openings 36 ₁ by the motor 37.
Can be changed from the fully closed state to the fully open state by simply rotating the vent hole 29 by a slight angle corresponding to the central angle of one vent hole 29, and the motor 37 can be reduced in size and responding. Simultaneous improvement is achieved.

Next, the structure of the passenger seat airbag device Rp will be described with reference to FIGS.

The support portion 4 extending from the lid 41 fixed to the opening 4 ₁ formed in the upper surface of the dashboard 4 downward
1 ₁ ..., retainer 43 of the airbag module 42 is fixed. The retainer 43 includes an upper retainer 45 and a lower retainer 46 fixed by a plurality of bolts 44.
The upper retainer 44 is fixed to the support portions 41 _{1 of the} lid 41 by a plurality of bolts 47. Upper retainer 45 and lower retainer 46
Of the airbag 48 is sandwiched by the joints of the airbags 48 and fastened together by the bolts 47. The lid 41 has a thin tear line 4 that breaks when the airbag 48 is inflated.
1 ₂ is formed. A cylindrical inflator 50 is supported on the bottom of the lower retainer 46 via a pair of mounting brackets 49, 49. Further, in order to open and close four vent holes 29 formed at the bottom of the lower retainer 46, the control valve 3 having the same structure as that of the airbag device Rd for the driver's seat is used.
0 is attached. The internal pressure of the airbag 48 is detected by an internal pressure detecting means 35d provided in the lower retainer 46.

The acceleration detecting means 35a, the occupant state detecting means 35b, the vehicle speed detecting means 35c and the internal pressure detecting means 35d
The energization of the inflator 50 and the control valve 30 is controlled by the airbag deployment control device 34 to which a signal from the airbag is input. That is, at the time of vehicle collision, the acceleration detecting means 3
5a detects an acceleration equal to or greater than a predetermined value, the inflator 50 is ignited by a command from the airbag deployment control device 34 to generate high-pressure gas, and the airbag 4 inflated by that pressure.
8 is deployed into the passenger compartment by breaking the tear line 41 _{and second} lid 41. At this time, the opening of the control valve 30 is feedback-controlled by signals from the occupant state detecting means 35b, the vehicle speed detecting means 35c, and the internal pressure detecting means 35d.

FIGS. 12 to 14 show a first modification of the passenger seat airbag device Rp. The structure of the control valve 30 is different from that described with reference to FIGS.

The control valve 30 according to the present modification includes an inflator 5
0 is a cross-sectionally arc-shaped valve plate 5 rotatably supported on the outer periphery
1 and a motor 37 as an actuator for rotating the valve plate 51. When the rotating valve plate 51 slides along the inner surface of the retainer 43, two slit-shaped vent holes 29, 29 formed in the retainer 43 are formed.
Have two corresponding slit-shaped openings 51 ₁ ,
It is opened and closed by a valve plate 51 having 51 ₁ .

As described above, the plurality of vent holes 29, 2
9 with a plurality of openings 51₁, 51 ₁Valve plate 51 having
Is controlled by the motor 37 being rotated by the motor 37, so that the valve plate 51 is
A slight angle turn corresponding to the central angle of the vent holes 29
Turn the vent holes 29 and 29 fully closed
It is possible to change from the
Responsiveness is enhanced.

FIGS. 15 to 17 show a second modification of the airbag device Rp for the passenger's seat. The structure of the control valve 30 is different from that described with reference to FIGS.

The control valve 30 of this modified example has a valve plate 52 slidably supported by a pair of guide rails 43 ₁ , 43 ₁ provided on the bottom surface of a retainer 43, and this valve plate 52 is connected to the guide rail 43 _1. , and a linear solenoid 53 as an actuator which reciprocates along a 43 _1. Valve plate 52
The are formed four vent holes 29 ... and the same shape and the same number of openings 52 ₁ ... arranged on a straight line is, the opening 52 of the valve plate 52 which is driven by a linear solenoid 53 ₁ ... vent hole 29 ... , The vent holes 29 ...
Is released.

As described above, the opening degree of the plurality of vent holes 29... Arranged in a straight line is controlled by reciprocating the valve plate 52 having the plurality of openings 52 ₁ . Can be changed from the fully closed state to the fully open state by moving the vent holes 29 by a small distance corresponding to the length of one vent hole 29, thereby improving the responsiveness. . Note that, instead of the linear solenoid 53, it is also possible to employ an actuator in which a large number of piezoelectric elements are stacked.

Next, the structure of the side collision airbag device Rs will be described with reference to FIGS.

A metal mounting bracket 62 extending forward of the vehicle body is fixed to a pipe frame 61 extending vertically along the right edge of the seat back 5 by welding, and an airbag module 63 is mounted on the right side of the mounting bracket 62. Are fixed with bolts 64, 64. A shape-retaining material 65 made of a coarse blanket extends from the front surface of the airbag module 63 to an intermediate portion in the thickness direction of the seat back 5 to the left side of the vehicle body, and is connected to a pipe frame (not shown) on the left side of the vehicle body. A mesh-shaped spring 66 is stretched around the inner periphery of the pipe frame 61.
A pad 67 made of sponge is mounted on a portion surrounded by the rear surface of the mounting bracket 62 and the rear surface of the mounting bracket 62. A pad 68 made of sponge is also provided on the front surface of the shape-retaining material 65.
Is attached.

The central portion of the front surface of the seat back 5 is covered with a first covering material 69, and both left and right sides and the upper portion of the first covering material 69 are covered with a second covering material 70. The left and right sides and the upper surface of the continuous seatback 5 are covered with a third covering material 71, and the rear surface of the seatback 5 is covered with a fourth covering material 72. First
The covering material 69 and the second covering material 70 are sewn at a sewing portion 73, and the second covering material 70 and the third covering material 71 are sewn at a sewing portion 74.

The airbag module 63 is made of synthetic resin.
A retainer 75 formed integrally with the retainer 75,
Holder 77 and retainer 75 and
And the holder 77 are mounted with the bolts 64, 64.
It is fastened to the socket 62 together. Retainer 75 faces right
Tray-shaped main body part 75₁And this body 7
5₁Hinge 75 on the rear edge_Two7 connected via
5_ThreeAnd the main body 75₁Top edge, leading edge and
Five locking claws 75 provided on the lower edge_Four... the lid part 75 _Threeupon
Five locking holes 75 provided at the edge, front edge and lower edge_Five... for
By stopping, the main body 75₁Cover to cover the opening of
Part 75_ThreeIs fixed.

The folded airbag 78 is packaged by the protection cover 79. The periphery of the opening of the airbag 78 and both ends of the protect cover 79 are sandwiched and fixed between the retainer 75 and the holder 77, whereby the inflator 80 fixed to the holder 77 is moved to the airbag 78.
Is stored inside. When the airbag 78 is inflated, the protect cover 79 is easily broken, and does not hinder the inflation.

Opening 77 formed in holder 77₁When,
Main body 75 of retainer 75₁Four vents formed in
Holes 29 and openings formed in the mounting bracket 62
62 ₁And a gas passage 68 formed in the pad 68₁When,
Through a space 81 formed on the rear side of the seat back 5.
The inside of the airbag 78 is connected to the outside of the seat back 5.
Pass. The opening of the four vent holes 29 is controlled.
The driver's seat airbag device Rd and the
Control valve having the same structure as that of the passenger seat airbag device Rp
30 is mounted inside the retainer 75.

Acceleration detecting means 35a, occupant state detecting means
35b, vehicle speed detecting means 35c and internal pressure detecting means 35d
To the airbag deployment control device 34 to which the signal from
To the inflator 80 and the control valve 30
Is controlled. Thus, in the event of a vehicle collision, the inflator 8
0 generates gas, an air bag is formed inside the retainer 75.
The plug 78 expands. The pressure at which the airbag 78 inflates is
Lid 75 of tena 75 _ThreeWhen acted on the locking claw 75_Four…
Is the locking hole 75_Five... off the lid 75_ThreeIs the hinge part 75
_TwoRotate around the body 75₁Is released. Lid 75
_ThreeIs transmitted to the third covering material 71 of the seat back 5
Then, the sewing portion 74 is broken, and the second coating material 70 and the third
The airbag is separated from the covering material 71 and passes through the gap.
78 extends forward along the inside of the front door
You.

Next, the driver-side airbag device Rd, the passenger-side airbag device Rp, and the side-impact airbag device R
The contents of the opening / closing control of the vent holes 29 of s, Rs will be specifically described with reference to FIGS.

The horizontal axis in FIG. 24 is the inflators 20, 50,
80 indicates the time since ignition, and the vertical axis indicates the airbag 2
The target values of the internal pressure of 1, 48 and 78 are shown. Immediately after the inflators 20, 50, and 80 are ignited, the tear line 16 _{2 of the} rear cover 16 is used in the driver's seat airbag device Rd.
Until (see FIG. 5) breaks, the tear line 41 _{2 of the} lid 41 is used in the passenger airbag device Rp (FIG. 11).
Until the airbag device R breaks.
In s and Rs, until the sewing portion 74 (see FIG. 18) is broken, the inflation of the airbags 21, 48, and 78 is suppressed, and the internal pressure of the airbag rapidly increases. Subsequently, when the rear cover 16, the lid 41, or the sewn portion 74 is broken and the airbags 21, 48, 78 rush out into the vehicle interior, the inertia increases the volume of the airbags 21, 48, 78. The internal pressure of the bag suddenly decreases, and the airbags 21, 48, 78 are further expanded and deployed by the gas generated by the inflators 20, 50, 80 to restrain the occupant.

At this time, the target internal pressure pattern of the airbags 21, 48, 78, particularly the deployed airbags 21, 4
The maximum value of the airbag internal pressure when the occupant is restrained at 8, 78 is changed depending on the physique of the occupant detected by the occupant state detecting means 35b. That is, when the occupant is an adult having a large weight as shown by the solid line, the opening degree of the vent holes 29 is reduced to increase the internal pressure of the airbags 21, 48, 78, and as shown by the broken line, If the child is a small child, the opening degree of the vent holes 29 is increased to reduce the internal pressure of the airbags 21, 48, 78, so that an optimal restraining force according to the occupant's physique is generated. Has become.

The target internal pressure patterns of the airbags 21, 48, 78 are changed according to the vehicle speed detected by the vehicle speed detecting means 35c. That is, as shown in FIG. 25, when the vehicle speed at the time of the collision is low, the occupant can use the airbags 21, 48, 78.
And the required restraining force becomes smaller, the target internal pressure pattern at the time of low-speed collision indicated by the broken line has a maximum value of the internal pressure as compared with the target internal pressure pattern at the time of high-speed collision indicated by the solid line. The timing is set so that the timing is delayed and the maximum value of the internal pressure is reduced.

When an appropriate target internal pressure pattern is selected according to the occupant state and the vehicle speed as described above, the actual airbag internal pressure detected by the internal pressure detecting means 35d is compared with the target internal pressure. As shown, when the actual airbag internal pressure is equal to or higher than the target internal pressure, the opening of the vent holes 29 is increased. When the actual airbag internal pressure is lower than the target internal pressure, the opening of the vent holes 29 is increased. Is reduced, feedback control for making the actual airbag internal pressure coincide with the target internal pressure is performed.

The opening degree A (t) of the vent holes 29... In the feedback control is calculated as a function of the time t by the following equation (1) of Example 1 or equations (2) and (3) of Example 2. It is determined. Here, R (t) is a target internal pressure, P (t) is an actual internal pressure, and C ₁ (t) to C ₄ (t) are correction coefficients. [Example 1] A (t) = [{C ₁ (t) −C ₂ (t)} R (t) + C ₂ (t) P (t)] / R (t) (1) [Example 2] When P (t) ≧ R (t), A (t) = C ₃ (t) {P (t) −R (t)} (2) When P (t) <R (t), A _{(t) = C 4 (t} ) {R (t) -P (t)} ... (3) in the above embodiment uses a commercially available pressure sensor as pressure detection means 35d, but the following otherwise The internal pressure detecting means 35d can be used.

In the embodiment shown in FIG. 27, the internal pressure detecting means 35 is formed by bonding a piezoelectric element 83 to a metal protector 84.
d is fixed with a bolt 86 so as to cover the opening 85 formed in the retainer 19 from the outside. When the internal pressure of the airbag increases and the amount of gas discharged from the opening 85 increases, the piezoelectric element 83 of the internal pressure detecting means 35d is deformed outward, and a potential difference corresponding to the deformation is generated. Therefore, the pressure inside the airbag can be detected by monitoring the potential difference.

The embodiment shown in FIG.
The strain gauge 87 is attached to the inner wall surface of the air bag. When the retainer 19 is deformed according to the change in the air bag internal pressure, the resistance value of the strain gauge 87 changes, so that the air bag internal pressure can be detected.

Although the embodiments of the present invention have been described in detail, various design changes can be made without departing from the gist of the present invention.

[0059]

As described above, according to the first aspect of the present invention, the control means drives the control valve to open and close by the actuator in accordance with the internal pressure of the airbag detected by the internal pressure detecting means, and the opening degree of the vent hole. , The amount of gas discharged from the vent hole is arbitrarily changed to match the internal pressure of the airbag with a preset internal pressure pattern. Performance can be enhanced.

According to the second aspect of the present invention,
The degree of opening of the vent hole can be controlled so that the airbag internal pressure according to the occupant's condition can be obtained, so that the size of the airbag internal pressure can be optimized according to the occupant's weight and changes in seating status. Can be set.

According to the third aspect of the present invention,
Since the opening of the vent hole can be controlled so as to obtain the airbag internal pressure according to the vehicle speed, the magnitude of the airbag internal pressure can be optimally set according to the magnitude of the vehicle speed.

According to the invention described in claim 4,
By forming the actuator with a piezoelectric element, the vent hole can be opened and closed at a low cost with a simple structure having a smaller number of parts than other actuators such as a motor and a solenoid.

According to the fifth aspect of the present invention,
By configuring the actuator with a plate-like piezoelectric element, not only is the structure of the actuator extremely simple, but also the piezoelectric element itself can be used as a valve body, further reducing the number of parts and cost. Can be reduced.

According to the invention described in claim 6,
By combining a plurality of vent holes formed in the retainer and a plurality of openings formed in the valve plate, the degree of opening of the vent hole can be changed from the fully closed state to the fully open state with a slight stroke movement of the valve plate. Becomes possible,
The miniaturization of the actuator and the improvement of the responsiveness are simultaneously achieved.

According to the seventh aspect of the present invention,
Since a plurality of vent holes arranged in the circumferential direction are opened and closed by a valve plate that is reciprocally driven by an actuator, a rotary output actuator such as a motor can be easily applied.

According to the invention described in claim 8,
Since a plurality of vent holes arranged in a linear direction are opened and closed by a valve plate which is reciprocally driven linearly by an actuator, a linear output actuator such as a linear solenoid or a laminated piezoelectric element can be easily applied.

[Brief description of the drawings]

FIG. 1 is a perspective view of a front part of a cabin of an automobile.

FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 in FIG. 2;

FIG. 4 is an enlarged sectional view taken along line 4-4 in FIG. 3;

FIG. 5 is an exploded perspective view of an airbag device for a driver's seat.

FIG. 6 is a view corresponding to FIG. 3 and showing a modification of the airbag device for the driver's seat;

FIG. 7 is an enlarged sectional view taken along line 7-7 of FIG. 6;

FIG. 8 is an enlarged sectional view taken along line 8-8 of FIG. 1;

9 is a sectional view taken along line 9-9 in FIG.

FIG. 10 is a view taken along line 10-10 of FIG. 9;

FIG. 11 is an exploded perspective view of an airbag device for a passenger seat.

FIG. 12 is a view showing a first modification of the airbag device for the passenger seat, corresponding to FIG. 9;

13 is a sectional view taken along line 13-13 of FIG.

FIG. 14 is a sectional view taken along line 14-14 of FIG. 12;

FIG. 15 is a view showing a second modification of the airbag device for the passenger seat, corresponding to FIG. 9;

16 is a sectional view taken along line 16-16 of FIG.

17 is a sectional view taken along line 17-17 in FIG.

FIG. 18 is an enlarged sectional view taken along line 18-18 of FIG. 1;

19 is a view in the direction of arrow 19 in FIG. 18;

20 is a sectional view taken along line 20-20 in FIG. 19;

FIG. 21 is a sectional view taken along line 21-21 of FIG. 19;

FIG. 22 is a sectional view taken along line 22-22 in FIG. 19;

FIG. 23 is a block diagram showing a control system for a vent hole opening degree;

FIG. 24 is a diagram showing an example of a change in a target internal pressure pattern depending on an occupant state.

FIG. 25 is a diagram showing an example of a change in a target internal pressure pattern depending on a vehicle speed.

FIG. 26 is an explanatory diagram of feedback control of a vent hole opening degree.

FIG. 27 shows a second embodiment of the internal pressure detecting means.

FIG. 28 is a diagram showing a third embodiment of the internal pressure detecting means.

[Explanation of symbols]

Reference Signs List 19 retainer 20 inflator 21 airbag 29 vent hole 30 control valve 31 piezoelectric element (actuator) 34 airbag deployment control device (control means) 35b occupant state detection means 35c vehicle speed detection means 35d internal pressure detection means 36 valve plate 36 ₁ opening 37 motor (Actuator) 43 Retainer 48 Airbag 50 Inflator 51 Valve plate 51 ₁ opening 52 Valve plate 52 ₁ opening 53 Linear solenoid (actuator) 75 Retainer 78 Airbag 80 Inflator

Claims (8)

[Claims] 1. A folded airbag (21, 48, 7)
8) A retainer (19, 43,
75), the inflator (20, 50, 80) is housed inside the inflator (20, 50, 80) in the event of a vehicle collision.
80), the airbag (21, 4) inflated with the gas generated.
8, 78) to deploy an airbag device for restraining an occupant. The airbag device operates by a vent hole (29) formed in the retainer (19, 43, 75) and an actuator (31, 37, 53). A control valve (30) for opening and closing a vent hole (29); an internal pressure detecting means (35d) for detecting an internal pressure of the airbag (21, 48, 78); and the air detected by the internal pressure detecting means (35d). An airbag device comprising: a control means (34) for performing feedback control of the opening of the vent hole (29) so that the bag internal pressure matches a preset internal pressure pattern. 2. An occupant state detecting means (35b) for detecting an occupant state, wherein said control means (34) controls said internal pressure pattern according to the occupant state detected by said occupant state detecting means (35b). The airbag device according to claim 1, wherein the airbag device is changed. 3. A vehicle speed detecting means (35c) for detecting a vehicle speed.
The airbag device according to claim 1, wherein the control means (34) changes the internal pressure pattern according to the vehicle speed detected by the vehicle speed detection means (35c). 4. The airbag device according to claim 1, wherein the actuator is a piezoelectric element. 5. The actuator (31) is a plate-shaped piezoelectric element arranged to cover the vent hole (29) and having one end fixed to the retainer (19, 43, 75). The airbag device according to claim 4, wherein 6. The retainer (19, 43) includes a plurality of vent holes (29) and the control valve (3).
0) is provided with a valve plate (36, 51, 52) in which a plurality of openings (36 ₁ , 51 ₁ , 52 ₁ ) respectively corresponding to the plurality of vent holes (29) are formed, and the actuator (37) is provided. , 53) are the valve plates (36, 51, 5).
2) sliding the plurality of openings (36 ₁ , 51 ₁ , 52 ₁ ) along the retainers (19, 43) to face the plurality of vent holes (29). Item 2. The airbag device according to item 1. 7. The plurality of vent holes (29) are arranged in a circumferential direction, and the valve plates (36, 51) are reciprocally driven by the actuator (37). Item 7. The airbag device according to item 6. 8. The device according to claim 6, wherein the plurality of vent holes are arranged in a linear direction, and the valve plate is reciprocally driven linearly by the actuator. The airbag device as described in the above.