JPH09295546A - Air bag module for driver's seat - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a driver properly protectable without imparting any large impact to the driver even in the case where an air bag is attached to a vehicle whose setting angle of a steering wheel is large enough. SOLUTION: In a driver's seat air bag module to be installed in a steering wheel 1, an inflator mounting hole 7 of an air bag 4 is installed in a spot as being decentered from a virtual center point 10 of this air bag 4. Then, the virtual center point 10 of the air bag 4 and a center point 8 of the inflator mounting hole 7 are on an axis 5 passing through a steering wheel center point 6 connecting 12 o'clock and 6 o'clock of the steering wheel 1, therefore the virtual center point 10 of the air bag 4 is positioned more upward than the steering wheel center point 6, and thus the center point 8 of the inflator mounting hole 7 is set up each so as to be positioned more downward than the steering wheel center point 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag module for a driver's seat and a steering wheel equipped with the module for ensuring the safety of a driver from an impact caused by a collision accident of an automobile.

[0002]

2. Description of the Related Art Conventionally, there are various airbag modules mounted on a steering wheel for deploying an airbag between a steering wheel and a driver to protect the driver when a vehicle crashes. In many of these, an inflator and an airbag in a folded state are fixed to a retainer fixed to a steering wheel, and this is covered with a bag cover fixed to the retainer.

As shown in FIG. 4, a representative conventional example thereof is that the head portion of the inflator 22 is fitted into the central hole 21 of the retainer 20 from below, and the flange portion 23 is attached to the retainer 2.
On the other hand, the opening end of the airbag 24 is brought into contact with the front surface of the retainer 20, and the reinforcing cloth 25 is laminated inside the opening end of the airbag, and the retainer is placed thereon. By arranging the rings 26, bolting them together, covering the bag cover 27 with the airbag folded, and fixing the leg portions 28 of the bag cover to the retainer 20 with the rivets 29. The bag module 30 is configured.

When the air bag module having the above-mentioned structure is operated, a squib incorporated in the inflator 22 is ignited by a signal from an impact sensor which detects an impact at the time of collision of a vehicle, whereby the gas generating agent is burned. Then, a large amount of high temperature and high pressure gas is instantly generated from the inflator. This gas is released into the folded airbag 24, deploys the airbag, destroys the fragile portion of the airbag cover by the deploying force, and the airbag deploys between the steering wheel and the driver, thereby protecting the driver. It is designed to protect against shock.

[0005]

As shown in FIG. 5, the angle θ of the steering wheel mounting the airbag module for the driver's seat with respect to the vehicle body is almost constant in the case of a general passenger car. The shape of the airbag is formed to be substantially circular in its deployed state. However, in the case of an off-road vehicle or a cab-over vehicle, the mounting angle θ becomes larger than that of a general passenger vehicle, and the steering wheel portion becomes nearly horizontal.

As described above, when the steering wheel mounting angle θ becomes large, when an airbag similar to the standard case of a general passenger car is mounted, the position of the airbag 24 deployed at the time of a collision is the position of the general passenger car. In the case of, the position of the two-dot chain line shifts to the position of the solid line. Therefore, when the airbag is deployed at the time of a collision, the airbag on the lower side of the steering wheel, that is, the portion at the 6 o'clock side when the steering wheel is regarded as a timepiece, has its inertia due to the collision. With strong force, the driver moves forward and enters the rim of the steering wheel at the 6 o'clock position. As a result, the driver who moves forward due to the inertial force receives most of the force at this portion and the deploying force of the airbag, so that the chest and abdomen of the driver who receives this force is strongly compressed. As a result, the chest and abdomen are damaged, and the proper function as an airbag is hindered.

Therefore, according to the present invention, even when an airbag is mounted on a vehicle having a large steering wheel mounting angle, it is possible to appropriately protect the driver without giving a great impact to the driver. An object is to provide an airbag module.

[0008]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention relates to a driver airbag module mounted on a steering wheel, wherein an inflator mounting opening of the airbag is eccentric from a virtual center point of the airbag. The imaginary center point of the airbag and the center point of the inflator mounting port thereof are provided with respect to the axis line passing through the steering wheel center point connecting 12 o'clock and 6 o'clock of the steering wheel when the steering wheel is in the neutral position. It is on the axis, the virtual center point of the airbag is located above the steering wheel center point, and the center point of the inflator attachment port is located below the steering wheel center point. By arranging them, the driver-seat airbag module is configured.

Since the present invention is configured as described above, when the airbag is deployed at the time of a vehicle collision, the lower end side of the airbag does not significantly deploy between the steering wheel and the driver. As a result, the number of airbags that forcibly enter between the driver who moves forward due to inertial force and the steering wheel is reduced, and even when the airbag is mounted on a vehicle with a large steering wheel mounting angle, the chest of the driver is reduced. It will function properly as an airbag without giving a big shock to the abdomen and the abdomen.

[0010]

Embodiments of the present invention will be described with reference to the drawings. A solid line in FIGS. 1 and 2 shows a first embodiment of the present invention, in which a perfect circular steering wheel 1 is fixed on the same central axis as a steering shaft 2, and the steering wheel 1 has the above-mentioned conventional structure. Inflator 3, airbag 4 via retainer
Also, a bag cover (not shown) is fixed.

The inflator 3 has a center point 6 of the steering wheel 1 on the axis of the center line 5 in the directions of 12 o'clock and 6 o'clock when the steering wheel 1 is in a neutral state as shown in the figure when it is regarded as a timepiece. Slightly below the center point 8 of the inflator mounting opening 7 of the airbag 4.
Is located. On the other hand, the center point 10 of the airbag 4 is arranged above the center point 6 of the steering wheel 1. In addition, the airbag 4 in the deployed state
Is a perfect circle in this embodiment, and its lower end 12
Is located above the lower end portion 13 of the steering wheel 1, and the upper end portion 14 of the airbag 4 is located above the upper end portion 15 of the steering wheel 1 as in the conventional case. The side end portion of the airbag 4 is located outside the steering wheel 1 like the conventional one.

Here, in FIG. 1, the sizes and relations of the airbag 4, the inflator 3, and the steering wheel 1 shown by A to E are as follows. A: The distance between the steering wheel center 6 and the inflator center 8 is shown, and the center position of the inflator 3, that is, the center 8 of the inflator mounting port of the airbag is positioned slightly lower than the center 6 of the steering wheel from the relationship of the moment of inertia. I am letting you. As a result, the center of gravity of the steering wheel equipped with the airbag module becomes lower than the center position of the steering wheel, and a force that naturally returns to the neutral position acts on the steering wheel. The value of A is a value determined when the steering wheel and the airbag module are assembled and designed. B: Airbag center 10 and steering wheel center 6
And the degree of eccentricity between the airbag 4 and the steering wheel 1. C: Steering wheel 1 when the airbag is deployed
3 shows the dimensions of the exposed portion of the lower end of the sheet that is not covered by the airbag. D: The external dimensions of the steering wheel 1 are shown, and those having a diameter of 360 to 380 mm are generally used. E: The outer dimension of the airbag when the airbag is deployed, which uniquely determines the sewn inner diameter of the bag. F: Steering wheel 1 when the airbag is deployed
Shows the dimensions of the portion where the airbag is exposed from the upper end of the.

In determining these relationships and dimensions, first, the airbag capacity is determined and the outer dimension E of the airbag is determined. Next, the dimension C of the lower end of the steering wheel 1 exposed from the airbag when the airbag is deployed
And steering wheel center 6 and airbag center 10
And the distance B is given by the following equation. B = C + (ED) / 2 Since the external dimension D of the target steering wheel 1 is known, B can be uniquely determined by appropriately setting C. On the other hand, since A is a value determined at the beginning of design as described above, the distance A + B between the airbag center 10 and the center 8 of the inflator mounting opening 7 is inevitably required.

In the airbag module 11 arranged in this way, when the airbag 4 is deployed at the time of a vehicle collision, the airbag 4 which is deployed by the driver's chest moving forward due to the inertial force at the time of the vehicle collision is first The driver's chest is inflated with the deployed airbag 4
Will collide near the lower end of the. Since the airbag does not exist near the lower end portion 13 of the steering wheel 1, the driver's chest and abdomen below the driver's chest are not pressed by the pressure of the airbag that strongly deploys. Compared with the case where the airbag is deployed beyond the lower end of the steering wheel, the abdomen and chest are less compressed, and the driver's chest and abdomen are protected from strong pressure by the airbag. Since the upper end and both sides of the airbag 4 are located outside the peripheral edge of the steering wheel 1 as in the conventional case, the driver's head and chest are protected.

Further, the upper end portion of the airbag has a function of protecting the driver's head by covering the upper end portion 15 of the steering wheel.
In the case of a perfect circular airbag 4, the distance F from the steering wheel upper end 15 to the airbag upper end 14 is F.
Is represented by F = C + ED, and as the value of C increases, F
Also increases. If F becomes too large, there will be a useless portion in the deployment area of the airbag.

Therefore, as indicated by a broken line 4-1 in the figure, it is preferable to adopt an upper flat type airbag in which an unnecessary portion of the upper portion is deleted to reduce the upper half. That is, the lower half is configured to have a circular shape similar to that of the above-described embodiment, and the upper half is an elliptical shape in which a central portion of the circular arc is connected to an arc having a large diameter R1 and a side portion is connected to an arc having a small diameter R2. The bag as a whole is preferably configured to have an oblong shape with a flat upper portion. In this case as well, the upper end of the airbag 4 is
The steering wheel 1 is positioned above the upper end portion 15. Further, the increase of the airbag capacity causes a problem that the adjustment of the internal pressure of the airbag can be restricted in the tuning with the inflator 3, but by reducing the wasteful capacity of the airbag 4 in this way, such a problem is also solved. be able to. In the above-mentioned embodiment, the shape of the upper half of the airbag is formed by two circular arcs having different radii R1 and R2. However, more circular arcs having different radii may be used. It may be oval.

Further, as another example of reducing the capacity of the airbag, as shown in FIG. 3, an airbag having a substantially rectangular shape in which the upper corner portion is removed in the deployed state of the airbag may be used. Also in this airbag, the lower edge 1 of the steering wheel is at the neutral position.
7 is located above the lower end 13 of the steering wheel, and the upper edge 18 is the upper end 15 of the steering wheel.
The stearer wheels are formed on the upper side, and the left and right side edges are formed on the outer side of the stearin wheel. At the same time, on the axis 5 connecting the 12 o'clock and the 6 o'clock in the neutral state of the steering wheel, the vertical center portion 10 as the airbag center is above the steering wheel center 6 and the center point of the inflator mounting port 7 8 is located below the center 6 of the steering wheel. Also,
Both upper corners of the airbag are formed with slanted edges 19 at the upper left and right ends in order to reduce unnecessary volume.

In the airbag of each of the above-mentioned embodiments, as described above, it is possible to relieve the pressure on the driver's chest and abdomen caused by the airbag when the airbag is operated. It is conceivable that the driver's chest or abdomen collides with the lower portion of the steering wheel via the lower portion of the airbag during a strong impact due to the reduction of the pressure exerted by the airbag. Therefore, in consideration of such a case, as shown by the dotted line in FIG. 2, the lower part of the steering wheel is easily deformed by its force in the case of a collision of the body, so that the lower part of the steering wheel can be easily deformed. It is desirable that the structure has low strength.

In the present invention, the shape of the airbag includes various shapes such as a perfect circle, a flat upper part, and a horizontally long rectangular shape as described above.
The virtual center point in the airbag of these shapes used in the present invention means the following. 1) If the shape of the airbag is circular, the center of the circle. 2) If the upper arc of the airbag is inside a virtual circle centered on the center of the lower arc, the center of the lower arc. 3) When the shape of the airbag is oval or elliptical, the intersection of the major axis and the minor axis. 4) If the shape of the airbag is substantially rectangular, the intersection of the vertical and horizontal centerlines.

[0020]

The present invention is configured as described above.
Even when the airbag is mounted on a vehicle with a large steering wheel mounting angle, when the airbag is deployed in the event of a vehicle collision, the deployment force of the airbag does not strongly press the driver's chest or abdomen. This allows the bag to function properly.

[Brief description of drawings]

FIG. 1 is a front view showing an airbag deployed state according to an embodiment of the present invention.

FIG. 2 is a side view showing the relationship between the steering wheel and the airbag in the airbag deployed state in the embodiment of the present invention.

FIG. 3 is a front view showing an airbag deployed state of another embodiment of the present invention.

FIG. 4 is a facial view of a general airbag module.

FIG. 5 is a side view showing an airbag deployed state of the off-road car.

[Explanation of symbols]

 1 Steering Wheel 2 Steering Shaft 3 Inflator 4 Airbag 5 Steering Wheel Center Axis 6 Steering Wheel Center Point 7 Airbag Inflator Mounting Port 8 Center Point of Inflator Mounting Port 10 Virtual Center Point of Airbag 11 Airbag Module 12 Lower end of airbag 13 Lower end of steering wheel 14 Upper end of airbag 15 Upper end of steering wheel

Claims (6)

[Claims] 1. A driver airbag module mounted on a steering wheel (1), wherein an inflator mounting opening (7) of an airbag (4) is eccentric from a virtual center point (10) of the airbag (4). When the steering wheel (1) is in the neutral position, the air bag (4) is provided with respect to the axis (5) passing through the steering wheel center point (6) connecting 12 o'clock and 6 o'clock of the steering wheel. The virtual center point (10) and the center point (8) of the inflator mounting port (7) are on the axis (5),
The virtual center point (10) of the airbag (4) is located above the steering wheel center point (6), and the center point (8) of the inflator mounting opening (7) is the steering wheel center point. An airbag module for a driver's seat, characterized in that the airbag modules are arranged so as to be located below (6). 2. The shape and size of the airbag (4) is such that an upper end portion of the airbag (4) in a state where the airbag (4) is deployed has the steering wheel (1).
Steering wheel (1) when the vehicle is in the neutral position
The upper end of the steering wheel (1) and the lower end of the airbag (4) are located above the lower end of the steering wheel (1). 3. The airbag module for a driver's seat according to claim 1, wherein the lower end of (1) is located outside the lower end of the airbag (4). 3. The airbag (4) is a flat type in which the upper and lower arcs have different radii of curvature, and the upper arc is a virtual circle centered on the center of the lower arc. The air bag module for a driver's seat according to claim 2, wherein the air bag module is an upper flat type inside. 4. The airbag (4) has a substantially rectangular shape whose horizontal length is larger than its vertical length.
The airbag module for the driver's seat described in. 5. The air bag (4) according to claim 4, wherein the upper side corners of the rectangle are removed.
The airbag module for the driver's seat described in. 6. A steering wheel equipped with an airbag module, wherein an inflator mounting opening (7) of the airbag (4) is provided eccentrically from a virtual center point (10) of the airbag (4), and steering is provided. The virtual center of the airbag (4) with respect to the axis (5) passing through the steering wheel center point (6) connecting the 12 o'clock and 6 o'clock of the steering wheel (1) when the wheel (1) is in the neutral position. The point (10) and the center point (8) of the inflator attachment port (7) are on the axis (5), and the virtual center point (10) of the airbag (4) is the steering wheel center point ( 6), and the center points (8) of the inflator mounting openings (7) are arranged below the steering wheel center point (6). And the airbag (4)
The shape and size of the steering wheel (1) are such that the upper end of the airbag (4) in the deployed state is the upper end of the steering wheel (1) when the steering wheel (1) is in the neutral position. Positioned above the steering wheel (1), the lower end of the steering wheel (1) is an airbag (4).
The lower part of the steering wheel (1), which is located outside the lower end of the airbag (4) and is located outside the lower end of the airbag (4), is formed so as to be easily deformable by an occupant's collision. A steering wheel equipped with an airbag module.