JPH02200549A - Air bag structure for automobile - Google Patents

Abstract

PURPOSE:To suppress the behavior of a steering wheel at the time of a shock by setting the interval between upper bolts fixing the upper portion of an air bag module longer than the interval between lower volts fixing the lower portion. CONSTITUTION:The volt interval L1 between two right and left upper fitting bolts 31a and 31b fixing the upper portion of an air bag module is set larger than the bolt interval L2 between two right and left lower fitting bolts 31c and 31d fixing the lower portion. The bending and twisting rigidity of steering spokes 53a and 53b at these portions is improved, when the upper body of a crew is moved forward and collides with an air bag 21 inflated and deployed from the air bag module and the forward inertial force of the crew is applied to the air bag 21 at the time of a car collision, a steering wheel 5 is not moved, and the shock absorbing effect of the air bag 21 is improved.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to improvements in airbag structures for automobiles.

[Prior Art] Conventionally, as an airbag device for an automobile, main components such as an airbag, a gas generator (inflator), and an ignition device (igniter) are housed in a case to form a single assembly unit (airbag module). ) and in which this airbag module is assembled to a steering wheel is generally well known (for example, see Japanese Patent Laid-Open No. 184546/1983).

In a vehicle equipped with such an airbag device, by attaching the airbag module to the steering wheel, the visibility of instruments such as meters attached to the instrument panel in front of the steering wheel is prevented from being impaired. To achieve this, the airbag module is usually installed with its center offset from the center of the steering shaft. Further, the air pack monoyl is supported at four points in order to obtain stability of support, and is fastened and fixed to the steering wheel by two upper bolts on the left and right sides and two lower bolts at equal intervals.

[Problem to be Solved by the Invention 21] However, for example, if the airbag module is installed so that its center is offset downward from the center of the steering wheel, the air will flow from the junction between the wheel ring and the steering spoke. Since the length of the steering spoke up to the upper fastening point of the pack module becomes longer, there is a concern that the bending and torsional rigidity of the steering spoke at this portion may decrease. This results in
During a vehicle collision, when the upper body of an occupant moving forward collides with the air pack inflated and deployed from within the air pack module, the forward inertia force of the occupant is transmitted through the air pack to the wheel ring and the above-mentioned steering spokes. It is conceivable that the wheel ring will behave as a torsional or bending load, reducing the impact absorption effect of the air pack.

Note that the space between the two left and right fastening points to the steering spokes is made rigid by fastening and fixing the air pack module.

This invention was made in view of the above problems, and even when the center of the airbag module is installed offset from the center of the steering wheel, it is possible to suppress the behavior of the steering wheel in the event of a collision. The purpose is to provide an automobile airbag structure.

[Means for Solving the Problems] Therefore, the present invention provides an airbag module that is attached to a steering wheel, and in a neutral steering state, the center of the airbag module is offset below the center of the steering wheel, Accordingly, in an automobile airbag structure in which the center of the wheel hub is also offset downward from the center of the steering shaft, the airbag module is connected to the steering wheel by two upper left and right bolts and two left and right bolts. It is fastened and fixed by lower bolts, and the interval between the upper bolts that fixes the upper part of the airbag module is set longer than the interval between the lower bolts that fixes the lower part of the airbag module. I did it as it was.

[Effects of the Invention] According to the present invention, since the bolt interval between the upper bolts is set longer than the bolt interval between the lower bolts, the distance between the upper bolts and the upper fastening point of the air pack module is increased. As the length of the steering spoke becomes shorter, the bending and torsional rigidity of the steering spoke improves in this area.In the event of a vehicle collision, the upper body of the occupant moving forward collides with the air pack inflated and deployed from the air pack module. When the forward inertial force of the occupant acts on the air pack, the steering wheel does not move, improving the impact absorption effect of the air pack.

[Example] Hereinafter, an example of the present invention will be described in detail based on the accompanying drawings.

As shown in FIG. 1O, the automobile 1 according to the present embodiment has a plurality of front sensors II disposed near the front sensor 2 at the front end of the vehicle body as collision detection means for detecting a collision of the vehicle, and a single-chamber Each front sensor 11 and each dash sensor 12 is electrically connected to a control unit 13 disposed within the instrument panel 4. It is connected to the. Each of the front sensors 11 and the dash sensor 12 is composed of, for example, a well-known G sensor, and the front sensor 11. ..., 11 has its sensitivity set relatively low, and the car! If a collision occurs, this will be detected and O
N is activated, while the dash sensors 12..., 12
is set to have a relatively high sensitivity, and is turned on when the impact force due to a collision exceeds a predetermined value.

On the other hand, as shown in FIG. 9, the steering wheel 5 includes the main components of the airbag device, such as the airbag, gas generator, and ignition device, as one unit, as will be explained in detail later. An airbag module 20 is attached, and the airbag module 2
0 is electrically connected to the control unit 13, and a command signal from the control unit 20 causes the bipod firing device to be activated.

Further, a meter 7 that displays, for example, the traveling speed is installed at a portion of the instrument panel 4 located in front of the steering wheel 5.
In order to ensure visibility, the airbag module 20 is mounted with its center offset by a predetermined amount from the center of the steering shaft 6, as will be explained in detail later.

In the above configuration, a car! When a collision occurs, at least one of the plurality of front sensors 11 is
When the ignition device is activated by the command signal from the control unit 13 and gas is instantaneously generated in the gas generator, the first O As shown by the two-dot chain line in the figure, the airbag 21 is inflated and deployed toward the occupant M by this gas.

The above airbag module will be explained below.

As shown in FIGS. 7 and 8, the airbag module 20 includes a gas generator 22 (inflator) that instantaneously generates gas through a reaction between a gas generating agent and an expansion agent, and a gas generator 22 (inflator) that instantly generates gas by, for example, being energized. It is equipped with an igniter 23 (igniter) that generates heat and causes a reaction between the gas generating agent and the expansion agent, and an air bag 21 that instantly inflates when filled with the gas generated by the inflator 22. Bag 21. The main components of the airbag device, such as the inflator 22 and the igniter 23, are fixed to the base plate 24, and the passenger side is covered with a case 25 (bag cover) to form one assembly unit. base plate 2
4 mounting bolts 31a, 3l fixed to the bottom surface of
b, 31c, and 31d are fastened and fixed to the steering spokes of the steering wheel 5.

In addition, the above mounting bolts 31a, 3 lb, 31c, 31d
There are two upper mounting bolts 3fa on the left and right for fixing the upper part of the airbag module 20.

31b are arranged at a predetermined interval L1, and lower mounting bolts 31c and 31d for fixing the lower portion of the airbag module 20 are arranged at a predetermined interval.

The above-mentioned inflation flakes 22 are connected to a plurality of (for example, 4 sets) bolts 32a and nuts 32b (from which the base plate 2
4, and an igniter 23 is located in the center of it.
is provided, and a large number of gas holes 22a are provided on the side surface of the airbag 22 to release generated gas into the airbag 21. Further, the airbag 21 has its peripheral edge sandwiched between the retainer ring 33 and the base plate 24 and is fixed with a number of rivets 34, and is folded and stored inside the bag cover 25. . Further, the igniter 23 is connected to a harness 26 (having a connector 27 attached to its tip), and the harness 26 is connected to a harness (not shown) on the control unit l 3 side via the connector 27. ).

The bag cover 25 is formed into a box shape with a substantially U-shaped cross section, and after storing the inflator 22, igniter 23, airbag 21, etc. fixed to the base plate 24, the lower end of the periphery is connected to the base plate 24. It is sandwiched between upper and lower reinforcing plates 35, 35 and left and right reinforcing plates 36, 36, and is fixed to the base plate 24 with a large number of rivets 37.

Furthermore, as shown in FIG. 6, the bag cover 25 has a horizontal groove 41a extending in the horizontal direction on the front side thereof;
Loop-shaped vertical m42 provided at both left and right ends of
On the other hand, on the back side of the bag cover 25, as shown by the broken line in FIG. 6, the loop-shaped vertical grooves 42a, A lateral groove 41b extending directly below the outer portion of the lateral groove 43a, and left and right longitudinal 1ff 42b, 43b provided at both ends of the lateral groove 41b and located directly below the outer portion of the surface side vertical 11442a, 43a. It is being That is, the bag cover 25 includes:
A horizontal groove 17N1 composed of front and back grooves 41a and 41b, and a left vertical groove 42 composed of front and back grooves M42a and 42b,
A substantially U-shaped groove portion 40 is provided, which is formed by a right vertical groove 43 made up of front and back grooves 43a and 43b.

In addition, a sheet-like reinforcing material 25r made of, for example, synthetic fibers knitted into a mesh shape is embedded in the bag cover 25 along its curved shape (see FIG. 8).
is arranged so as not to interfere with the groove 40, and acts as a core material that maintains the shape of the bag cover 25, and when the bag cover 25 is opened, the cover 2
5 from being crushed into small pieces and scattered.

Then, when a collision occurs in the automobile 1 and the airbag device is activated and the airbag 21 is inflated, the inflation pressure of the airbag 21 causes the lateral grooves 4 on the front and back sides.
The thin wall portion 4.1c (see FIG. 8) formed between a and 4Ib is broken, and the bag cover 25 is divided into upper and lower parts, and also between the longitudinal grooves 42a and 42b on the front and back sides and between 43a and 4Ib.
The bag cover 25 is opened vertically by breaking the thin wall portions formed between the bag covers 3b and 3b. still,
In this embodiment, the vertical grooves 42a and 4.3a on the front side are formed in a loop shape, and the loop portions are opened left and right, so that the bag cover 25 can be used not only in the vertical direction but also in the horizontal direction. The airbag 21 is also opened slightly to allow the airbag 21 to deploy smoothly.

By the way, in this embodiment, the airbag module 2
In order to ensure the visibility of the meter 7 located in front of the steering wheel 5 when assembling the airbag module 20 to the steering wheel 5, the center of the airbag module 20 is offset downward from the center of the steering wheel 5. installed in condition.

Hereinafter, a structure for attaching the airbag module 20 to the steering wheel 5 will be explained.

As shown in FIGS. 1 and 2, the steering wheel 5 includes a plate-shaped wheel hub 51 that is provided at the tip of the steering shaft 6 and supports a wheel ring 52, and the wheel hub 5I and the wheel ring. 52, four steering spokes 53a, 53b,
53c, 53d, and the spokes 53a, 5
3b, 53c, and 53d have one end connected to the wheel hub 51.
and the other end is fixed to the wheel ring 52.
By being joined to the core metal 52a of the wheel hub 5
I and the wheel ring 52 are connected. Incidentally, among the steering spokes 53a, 53b, 53c, and 53d, the upper spokes 53a and 53b are integrally formed from a single plate.

The head of a steering shaft 6 that extends toward the vehicle interior through a core cover 57 that covers the rear side of the wheel hub 51 is inserted into the wheel hub 51.
is integrally fixed to the wheel hub 51, for example, by tightening with a fastening member (not shown) such as a nut.

Further, the wheel hub 51 is provided with a rectangular harness hole 51b through which a steering harness (not shown) connecting the control unit 13 and the airbag module 20 is inserted, as shown in detail in FIG. In addition, the core cover 57 is inserted into the harness hole 51b.
A harness guide portion 57a is fitted therein. The tapered lower end portion of the harness guide portion 57a is formed such that the outer side of the steering wheel 5 is largely inclined, and guides the harness inserted therethrough while avoiding interference with the steering shaft 6.

As shown in detail in FIG. 4, a lip portion 25s is formed on the outer periphery of the steering side end of the bag cover 25 of the airbag module 20, so that when the airbag module 20 is assembled to the steering wheel 5, The upper end portion of the core cover 57 is fitted inside the lip portion 25s to hide the connecting portion between the two portions 25 and 57, thereby improving its appearance. Further, as shown in FIG. 5, a recess 25f is formed in the square mounting portion of the bag cover 25 for the steering pole 5, and a wheel cover 52b covering the core bar 52a of the wheel ring 52 A convex portion 52c that fits into the concave portion 25f is formed at the attachment portion for the bag cover 25, and the air bag module 20
The bag cover 25 and the wheel ring 52 are seen from above when assembled to the steering wheel 5.
Most of the gap between the connecting portion and the convex portion 52c is hidden by the convex portion 52c,
The appearance of the connecting portion can be improved.

In addition, the above steering spokes 53a, 53b53c
, 53d have mounting holes 54a, 54., through which the mounting bolts 31a, 3lb, 31c, 31d of the airbag module 20 are inserted, respectively. b, 54c, and 54d, and among these, for example, the mounting hole 54a
Only the mounting holes 54b, 54 are formed in a circular shape, and the other three mounting holes 54b, 54
c and 54d are formed into oval shapes. When assembling the airbag module 20, the circular mounting hole 54. Set a as the reference hole, and first set this reference hole 5.
After inserting the mounting bolt 31a into 4a, insert the other mounting bolt 31b.

31c and 31d are oval mounting holes 54b and 54, respectively.
c, 54d, and insert the airbag module 20 into the airbag module 20.
By positioning the airbag module 20 with respect to the steering wheel 5, the airbag module 20 can be positioned easily and accurately.

Furthermore, in this embodiment, the airbag module 20 has its center Ce (that is, the center of the inflator 22) a predetermined distance ff1 from the center Cs of the steering shaft 6.
The center of the wheel hub 51 is also offset downward by the same amount to allow the airbag module 2 to be installed.
0 center Ce. On the other hand, more preferably, the wheel ring 52 has a center channel that is a predetermined distance 14 points from the center Cs of the steering shaft 6.
The airbag module 20 is offset upwardly by the airbag module 20 to suppress the unbalance of the weight of the steering wheel 5 caused by the downward offset of the airbag module 20, and to ensure the steering stability of the steering wheel 5. It has become.

By the way, in this embodiment, two upper mounting bolts 31a on the left and right sides fixing the upper part of the airbag module 20,
31b (that is, the distance between the mounting hole 54a and the mounting hole 54b) L, is the two left and right lower mounting bolts 31c that fix the lower part of the airbag module 20,
31d is set larger than the bolt interval Lt (that is, the interval between the mounting hole 54c and the mounting hole 54d). In other words, the length of the steering spokes 53a, 53b from the joining point of the core metal 52a of the wheel ring 52 and the steering spokes 53a, 53b to the upper fastening points 54a, 54b of the air pack module 20 is set to be shorter. . Therefore, the bending and torsional rigidity of the steering spokes 53a, 53b is improved at this portion, and the upper body of the occupant who has moved forward collides with the airbag 21 inflated and deployed from the air pack module 20 in the event of a vehicle collision. Is the forward inertia force near back 21? When the second action occurs, the steering wheel 5 does not move and the impact absorption effect of the airbag 21 is improved.

[Brief explanation of the drawing]

All drawings are for detailed explanation of the present invention.
Figure 1 is a plan view of the main parts of the steering wheel, Figure 2 is a partial sectional view taken along the line B-B in Figure 1, Figure 3 is a partial sectional view taken along the line C-C in Figure 1, and Figure 4. is an enlarged sectional view of the joint between the bag cover and the core cover, FIG. 5 is a perspective view of the joint between the bag cover and the wheel ring, FIG. 6 is a plan view of the bag cover, and FIG. 7 is an airbag. A plan view of the back side of the module, FIG. 8 is a cross-sectional explanatory view taken along the line A-A in FIG. 7, FIG. 9 is a plan view of the steering wheel with the airbag module installed, and FIG. It is an explanatory diagram. l...Car, 5...Steering wheel, 6.
... Steering shaft, 20... Airbag module, 21-, :r, Avalug, 31a, 3 lb,
31c 31d...Mounting bolt, 51...Wheel hub, 54a. 54b, 54c, 54d...Mounting hole, Ce...Airbag module center, Ch...Wheel ring center, Cs...Steering shaft center, E
...Airbag module offset amount.

Claims (1)

[Claims] (1) An airbag module is attached to the steering wheel, and in a neutral steering state, the center of the airbag module is offset downward from the center of the steering shaft, and accordingly, the center of the wheel hub is also aligned with the center of the steering shaft. In an automobile airbag structure that is offset downward from the airbag module, the airbag module is fastened and fixed to the steering wheel by two upper bolts on the left and right and two lower bolts on the left and right, and the airbag module is The distance between the above upper bolts that secure the upper part of the module is
An airbag structure for an automobile, characterized in that the interval is set longer than the interval between the lower bolts that fix the lower part of the airbag module.