JPH0813628B2 - Air bag device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air bag device that is mounted on a steering wheel and inflates the bag when the vehicle rapidly decelerates.

[Conventional technology]

Some air bag devices are mounted on a steering wheel to expand the bag when the vehicle is rapidly decelerated (Japanese Patent Laid-Open Nos. 60-248454 to 60-248457).

In this type of air bag device, a base plate attached to the steering wheel is provided, a cover is attached to the base plate, and the bag is stored in a folded state between the cover and the base plate. Further, an inflator is attached to the base plate in a state of being inserted into the bag, and the bag is inflated by the inflator. A starting device is attached to the inflator so as to correspond to the axial center portion, and is operated by the starting device. The starter is provided with a ball that moves at an acceleration when the vehicle suddenly decelerates, and the movement of the ball can detect the vehicle sudden deceleration to activate the inflator when the vehicle suddenly decelerates. The inflator can be activated to inflate the bag.

By the way, in order to accurately detect sudden vehicle deceleration, it is desirable to provide a plurality of balls in the starting device.

However, if the starter is provided with a plurality of balls,
As shown in the figure, the center of rotation of the steering wheel 10,
That is, the distances from the shaft center portion 10A to the balls 14 are not equal, and there is a possibility that the sensitivity of the vehicle sudden deceleration may vary. That is, when the intermediate point 12A of each ball 14 is attached to the steering wheel 10 in a biased state without being aligned with the axial center portion 10A which is the axial center extension line of the steering wheel 10, for example, each ball 14 is accommodated. Starter
When 16 is rotated around the shaft center (corresponding to the intermediate point 12A of each ball 14) and assembled, the distance from the shaft center 10A of the steering wheel 10 to each ball 14 as shown in FIG. May not be equal to each other, and the acceleration transmitted from the axial center portion 10A of the steering wheel 10 to each ball 14 may vary, resulting in variation in the sensitivity of the vehicle sudden deceleration.

[Problems to be Solved by the Invention]

In consideration of the above facts, an object of the present invention is to provide an air bag device which can prevent variations in the sensitivities of the respective sensor members even when a plurality of sensor members such as balls for detecting sudden vehicle deceleration are provided.

[Means for Solving the Problems] In an air bag device according to the present invention, the air bag device is mounted on a steering wheel and expands the bag when the vehicle suddenly decelerates, and a plurality of sensor members that sense when the vehicle suddenly decelerates. And an ignition mechanism which is provided corresponding to each of the plurality of sensor members and is operated by the sensor members to ignite and burn the gas generating substance for bag expansion, and the plurality of sensor members, It is characterized by being symmetrically arranged with respect to a vertical plane that intersects with the center of rotation of the steering wheel and extends in the vehicle front-rear direction.

[Action]

In the present invention having the above configuration, the plurality of sensor members are arranged symmetrically with respect to the vertical plane extending in the vehicle front-rear direction intersecting the steering wheel rotation center.

Therefore, each sensor member can be arranged at a position equidistant from the center of rotation of the steering wheel. As a result, when the vehicle is rapidly decelerated, it is possible to eliminate variations in the acceleration transmitted from the axial center of the steering wheel to the respective sensor members, and to make the respective sensor members equal in sensitivity.

〔Example〕

1 to 5 show an air bag device 20 according to a first embodiment of the present invention.

In the air bag device 20, as shown in FIG. 5, a base plate 24 is supported by a hub 22A of the steering wheel 22 substantially in parallel. 2 on the base plate 24
6, cover 28 and inflator 30 are attached.

The bag 26 is on the occupant side of the base plate 24 (upper side in FIG. 5).
It is arranged in a folded state. The opening 26 of the bag 26 has a ring plate at the substantially central portion of the base plate 24.
Installed via 32. The ring plate 32 is clamped and fixed to the base plate 24 with a bolt (not shown), and the edge of the bag 26 on the opening side is sandwiched between the ring plate 32 and the base plate 24.

As shown in FIG. 1, the cover 28 has a center portion 28A which is offset by a length L with respect to an axial center portion 22B which is an axial center extension line of the steering wheel 22 when viewed from the axial direction of the steering wheel 22 in FIG. Base plate 24 as shown in
It is located on the passenger side (upper side in FIG. 5) of the base plate 24
Stores bag 26 between and. A mandrel (not shown) is embedded in the periphery of the cover 28, and is fixed to the peripheral portion of the base plate 24 by a ribet or the like via the mandrel. A thin portion 36 is formed on the cover 28 at a portion facing the base plate 24, and is easily broken at this portion.

As shown in FIG. 1, the inflator 30 is also shown in FIG. 5 in a state in which the axial center portion is offset from the axial center portion 22B of the steering wheel 22 by the length L, that is, coaxial with the central portion 28A of the cover 28. As described above, the base plate 24 is inserted through the substantially central portion thereof and inserted in the bag 26. As shown in FIG. 2, the inflator 30 includes an upper case 30B having a flange 30A formed on the outer periphery thereof and an upper case 30B.
The outer case is composed of the lower case 30C that is welded to B, and the base plate 2 is attached via a flange 30A with a bolt (not shown).
It is fixed to the surface on the side opposite to the occupant 4 (lower side in Fig. 5).

The inflator 30 has a gas generating substance 38 enclosed inside and a starter 40 built therein. The gas generating substance 38 is decomposed by combustion to release a large amount of gas, and the gas 26 can be expanded by this gas.

The starting device 40 is housed in a tubular portion 30D formed in the lower case 30C of the inflator 30, and is arranged coaxially with the inflator 30. As shown in FIG. 3, the starting device 40 is provided with a spherical ball 44 in a case 42 so as to be movable in a state of being housed in a cylinder 46.

Two balls 44 are provided as shown in FIG. 4, and these are moved in front of the vehicle (direction of arrow A) by acceleration when the vehicle is rapidly decelerated. Each of these balls 44 has
Drive Shaft 47 is supported respectively.

The drive shaft 47 is rotatably supported via a pin 48 as shown in FIG. 3, and when the ball 44 moves forward of the vehicle (in the direction of arrow A), the movement of the ball 44 at this time causes the ball 44 to move counterclockwise in FIG. It is designed to rotate in the direction. A compression coil spring 52 is engaged with the drive shaft 47 via a retainer 50, and an ignition pin 56 is engaged with the pawl 54.

The compression coil spring 52 urges the drive shaft 47 in the clockwise direction in FIG. 3 via the retainer 50, and the ball 44 moves forward (in the direction of arrow A) via the drive shaft 47 due to vibration during normal vehicle traveling. I try not to.

When the drive shaft 47 rotates counterclockwise in FIG. 3, the ignition pin 56 is released from the engagement state with the claw 54 by this rotation. The ignition pin 56 is urged rearward of the vehicle (direction of arrow B) via the compression coil spring 58, and when the engagement state with the claw 54 is released, the urging force of the compression coil spring 58 urges the vehicle rearward (arrow B). Direction) and collide with a detonator 60 (also shown in FIG. 5) outside the case 42. The detonator 60 is configured to burn the gas generating substance 38 in the inflator 30 when it collides with the ignition pin 56.

Therefore, the starter 40 can detect the sudden deceleration of the vehicle and burn the gas generating substance 38 in the inflator 30 by moving the ball 44 with the acceleration at this time during the rapid deceleration of the vehicle.

As shown in FIG. 1, the starting device 40 is assembled in a state in which the balls 44 are positioned so as to be equidistant from the shaft center portion 22B of the steering wheel 22.

More specifically, as shown in FIG. 1, a notch 64 is formed on the outer periphery of the flange 30A of the inflator 30, and a bracket that engages with the notch 64 on the surface of the base plate 24 opposite to the occupant (lower side in FIG. 3). 66 is secured and the inflator 30 is covered by the engagement of the bracket 66 with the notch 64.
It is designed to be positioned at a fixed position around the central portion 28A of 28.

Further, two pin-shaped protrusions 68 are formed on the outer periphery of the case 42 of the starting device 40 at equal intervals from the axis of the case 42.
The axes of the balls 44 are arranged on the extension lines of the axes of the protrusions 68. In addition, the inflator 30
An engaging hole 70 that engages with the convex portion 68 is formed in the upper case 30B of the starting device 40 by the engagement of the convex portion 68 with the engaging hole 70.
Is positioned at a fixed position around the axis of the inflator 30.

As a result, the starting device 40 is positioned around the shaft center of the inflator 30 and the central portion 28A of the cover 28, and each pole 44 of the starting device 40 is positioned so as to be equidistant from the shaft 22B of the steering wheel 22. It is supposed to be done.

 Next, the operation of this embodiment will be described.

At the time of sudden deceleration of the vehicle, the ball 44 of the starter 40 moves toward the front of the vehicle (in the direction of arrow A) due to acceleration to detect the sudden deceleration of the vehicle. Rotate in the direction. This rotation claws 54
The engagement state between the ignition pin 56 and the ignition pin 56 is released, the ignition pin 56 is moved rearward (in the direction of arrow B) by the urging force of the compression coil spring 58, and collides with the detonator 60 outside the case 42. The gas generating substance 38 in the inflator 30 is burned. The gas generating substance 38 is decomposed by combustion to release a large amount of gas, and the gas 26 expands the bag 26. Due to this expansion, the cover 28 is pressurized from the inside, and the thin portion 36 of the cover 28 is broken by this pressure, and the bag 26 is interposed between the occupant and the steering wheel 22.

Here, since the balls 44 of the starting device 40 are respectively positioned so as to be equidistant from the axial center portion 22B of the steering wheel 22 when the balls 44 are assembled, the steering wheel
Acceleration transmitted from the shaft center portion 22B of 22 does not vary, and rapid vehicle deceleration can be accurately sensed.

That is, when assembled, the flange 30 of the inflator 30 is
The bracket 66 is engaged with the notch 64 of A and the inflator 30
Is positioned around the central portion 28A of the cover 28. Also,
The projection 68 of the case 42 of the starter 40 is engaged with the engagement hole 70 of the upper case 30B of the inflator 30, and the starter 40 is positioned around the axial center of the inflator 30. As a result, the activation device 40 causes the axial center of the inflator 30 and the cover 28.
The balls 44 of the starter 40 are positioned around the central portion 28A of the steering wheel 22 so that they are equidistant from the axial center portion 22B of the steering wheel 22.

Therefore, when the vehicle suddenly decelerates, the steering wheel
The acceleration transmitted from the shaft center portion 22B of 22 to each ball 44 does not vary, and the sensitivities of the balls 44 of the activation device 40 are equal.

In the above embodiment, the upper case 30B and the lower case 30C of the inflator 30 are welded, but the inflator 30
In the engaging hole 70 of the upper case 30B of
It suffices that the starter 40 be positioned around the axial center of the inflator 30 by engaging the convex portion 68 of the above, and the lower case 30C may be fixed to the upper case 30B with bolts or rivets.

Next, a second embodiment of the present invention will be described with reference to FIG.

The present embodiment and the first embodiment are different only in the structure and assembly of the inflator, and are the same in other constitution and operation. Further, in the description of the present embodiment, the same members and the like as those of the first embodiment in the drawings will be denoted by the reference numerals of the first embodiment and description thereof will be omitted.

Also in this embodiment, the inflator 130 includes the upper case 130B and the lower case 13 welded to the upper case 130B.
0C and the activation device 140.

Since the structure and operation of the starting device 140 are the same as those of the first embodiment, the description thereof will be omitted.

The upper case 130B has a flange 130A and is in a substantially hated state. A through hole 132 into which the bolt 160 is inserted is formed at the center of the top of the upper case 130B. The shape of the flange portion 130A and this flange portion 130A
The notch 164 provided on the outer periphery of the flange 3 is the flange portion 3 of the first embodiment.
Since the structure and operation are the same as those of 0A and the notch 64, description thereof will be omitted.

The lower case 130C is provided with a protrusion 140 at the center, and the cylindrical side wall 142 and the top wall forming the protrusion 140 are formed.
An accommodating portion 145 for accommodating the activation device 40 is provided together with 144. A protrusion 146 is provided from the center of the top wall 144 in the same direction as the above-mentioned protrusion 140.
A through hole 148 having a thread groove is provided at the center of the. The diameter of the protrusion 146 is the same as the above-mentioned upper case 1.
The size is set so as to fit into the through hole 132 of 30B.
Further, on the inner surface of the top wall 142, the convex portion 6 provided on the activation device 40 is provided.
An engaging hole 170 into which 8 is inserted and engaged is formed. Therefore, the engagement of the convex portion 68 with the engagement hole 170 positions the starter 40 at a fixed position around the axial center of the inflator 30. The outer peripheral portion of the lower case 130C has an annular flange 180 protruding in the same direction as the above-mentioned protruding portion 144.
Is provided for welding with the upper case 130C.

Assembling of each member configured as described above will be described.

The protrusion 146 of the lower case 130C is fitted into the through hole 132 of the upper case 130B. At that time, the gas generating substance and the detonator are arranged at predetermined positions in the annular space between the lower case 130C and the upper case 130B. Mated lower case 130C
The upper case 130B and the upper case 130B are positioned with respect to each other, the bolt 160 is screwed into the through hole 148, and the lower case 13
The end surface of the flange 180 of 0C and the surface of the upper case 130B with which this end surface abuts are welded. Next, the activation device 40
The protrusion 68 is fitted into the housing portion 145 of the protrusion 140 provided in the lower case 130C, and the protrusion 68 is inserted and engaged in the engagement hole 170 to be positioned and fixed to the lower case 130C.

The inflator 130 thus assembled is assembled to the base plate 24 as in the first embodiment.

Since the operation of this embodiment is similar to that of the first embodiment, its explanation is omitted.

Although the air bag device is rotated together with the steering wheel in the above-described first and second embodiments, the present invention is not limited to such a case, and the air bag device is not rotated even when the steering wheel is rotated. Of course, the above can be applied.

〔The invention's effect〕

As described above, the air bag device according to the present invention has an excellent effect that the sensitivity of each sensor member can be prevented from varying even when a plurality of sensor members for detecting the rapid vehicle deceleration are provided.

[Brief description of drawings]

1 to 5 show an air bag device according to a first embodiment to which the present invention is applied, and FIG. 1 is a front view of the ball arrangement of the starting device of FIG. 5 seen from the upper side of the steering wheel, and FIG. 5 is an exploded perspective view of the main part of FIG. 5, FIG. 3 is a cross-sectional view showing the internal structure of the starting device of FIG. 2, and FIG. 4 is of FIG.
A sectional view taken along the line IV-IV, FIG. 5 is a schematic sectional view showing the entire structure, FIG. 6 shows a second embodiment of the present invention, and an exploded perspective view of an essential part corresponding to FIG. 2, FIG. FIG. 6 is a front view of the arrangement of balls of a starting device in a conventional air bag device as viewed from above a steering wheel. 20 …… Air bag device, 22 …… Steering wheel, 24 …… Base plate, 26 …… Bag, 28 …… Cover, 30,130 …… Inflator, 40 …… Starting device, 44 …… Ball (sensor member), 64 ... notch (first positioning means), 66 ... bracket (first positioning means), 68 ... convex portion (second positioning means), 70 ... engaging hole (second positioning means).

Claims (1)

[Claims] 1. An air bag device which is adhered to a steering wheel and expands the bag when the vehicle suddenly decelerates.
A plurality of sensor members for detecting the sudden deceleration of the vehicle, and an ignition mechanism provided corresponding to each of the plurality of sensor members and operated by the sensor members to ignite and burn the gas generating substance for expanding the bag. And the plurality of sensor members are symmetrically arranged with respect to a vertical plane that intersects with the center of rotation of the steering wheel and extends in the vehicle front-rear direction.