JP2002166808A - Air bag system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily control the operation of a cover body and an air bag at the time of inflating an air bag system. SOLUTION: Pressure of expansion of the air bag breaks a tear line 33 of the cover body 26 to form an upper door portion and a lower door portion 52. The length L1 of the upper door portion is longer than the length L2 of the lower door portion 52, in a vertical direction. The upper door portion is split into right and left portions along an upper tear line 42 to form upper side door portions 51, 51 rotating to be open in both directions. Therefore, the locus of inflation toward the front of the door portion can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag device provided on a steering wheel of a vehicle and using an airbag which is inflated and deployed, for example.

[0002]

2. Description of the Related Art Conventionally, for example, an airbag device for a driver's seat provided in a boss portion of a steering wheel of an automobile and inflating a bag-like airbag by inflow of gas to reduce the impact of a collision applied to an occupant. Is used. The airbag used in the airbag device is housed inside the cover body in a small folded state, the cover body is broken by the pressure of the gas supplied from the inflator, and swells to the occupant side, and the airbag is moved forward. It is designed to catch and restrain the thrown occupants and reduce the impact.

The cover body is formed of, for example, a synthetic resin, and breaks along a tear line formed more weakly than other parts under the pressure of an airbag, and a part of the cover body is developed in a door shape. Thus, a projecting opening of the airbag is formed. Regarding the arrangement of such tear lines, for example, as described in JP-A-7-32964, upper and lower door portions are formed by a central tear line extending in both sides, and the lower door is formed. Is known to be divided into door portions on both sides by a tear line extending downward from a central tear line. That is, in this configuration, the cover body is configured to rotate using the upper and lower sides as hinges.

Further, as shown in, for example, Japanese Patent Application Laid-Open No. 9-118187, the folded airbag is wrapped in a band-like body, and the folded shape of the airbag is maintained to improve the workability of assembling the airbag device. Is known.
In the configuration described in this publication, the strip is smoothly broken along a break such as a perforated hole crossing the strip.

[0005]

At present, an airbag apparatus capable of easily securing good deployment characteristics for occupants at various sitting positions, including not only the behavior of the airbag but also the behavior of the cover body. Is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an airbag device capable of easily improving deployment characteristics.

[0007]

The airbag device according to the first aspect of the present invention is an airbag that is inflated and deployed by supplying gas, and covers the airbag when it is not deployed, and is broken by the pressure at which the airbag is inflated. A cover body having a portion to be broken and a plurality of doors formed by breaking the portion to be broken and having a facing portion facing the protected object, wherein the portion to be broken extends in both side directions; 1, a line to be broken;
A second breakable line extending upward from an intermediate portion of the first breakable line, and a first breakable line that is continuous with the tip of the second breakable line and substantially along the first breakable line; A third scheduled break line portion extending in both lateral directions, the first scheduled break line portion defines an upper door portion and a lower door portion constituting the door portion, and a second scheduled break line portion and The third line to be broken defines a pair of upper side doors constituting the upper door, and the dimension of the upper door in the vertical direction is set to be larger than the dimension of the lower door in the vertical direction. It is a thing.

[0008] In this configuration, with respect to the plurality of door portions formed by breaking the portion to be broken, the upper door portion whose vertical dimension is larger than that of the lower door portion has the second scheduled break line portion and Since a pair of upper side doors on both sides are defined by the third line to be broken and are deployed laterally, the turning trajectory of the upwardly directed door is particularly small, and the deployment characteristics are easy. To improve.

According to a second aspect of the present invention, in the airbag apparatus according to the first aspect, the shape combining the upper door portion and the lower door portion is substantially square, and the second line to be broken is , Partitioning the upper door portion at substantially the center in both sides,
The dimensional ratio between the upper door portion and the lower door portion in the vertical direction is in a range of 55:45 to 70:30.

[0010] With this configuration, the size and direction of the rotation locus of each door portion is appropriate, and the deployment characteristics are easily improved.

According to a third aspect of the present invention, there is provided the airbag apparatus according to the first or second aspect, wherein the airbag is wrapped in a non-deployed state when the airbag is not inflated and the folded shape is maintained. It is provided with a holding means provided with a guide break scheduled portion for guiding.

In this configuration, the direction of deployment of the airbag is guided by the guide breakable portion of the holding means, which is a member for maintaining the folded shape and facilitating the assembly of the airbag device, and the deployment characteristics are easily improved. I do.

According to a fourth aspect of the present invention, there is provided the airbag apparatus according to the third aspect, wherein the portion of the holding means which is to be guided to break is connected to a connecting part provided at a central portion in the longitudinal direction across the holding means. , And a continuous notch at both ends of the connecting portion.

In this configuration, the peripheral portion of the airbag which is opposed to the notch portion of the holding means is deployed, and then the connecting portion is broken and the central portion is deployed. Suitable deployment characteristics for quickly deploying are easily realized. Then, the configuration is simple and the manufacturing cost is reduced.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the airbag device of the present invention will be described below with reference to the drawings.

In FIGS. 2 and 3, reference numeral 1 denotes a steering wheel of an automobile, which is a vehicle. It is composed of an airbag device 4 and the like.
The steering wheel 1 is usually mounted on a steering shaft inclined at a predetermined angle and used in an inclined state. Hereinafter, the occupant side of the airbag device 4 will be referred to as a front side (see FIGS. 1 and 2). The direction of the arrow B1 shown in FIG.
2), and at the rotational position in the straight running state of the car, the direction perpendicular to the front and back direction and toward the front upper side of the vehicle body is the upward direction (the direction of arrow C1 shown in FIGS. 1 and 3), and the rear lower side 1 is a downward direction (direction of arrow C2 shown in FIGS. 1 and 3), a direction along both sides of the vehicle body, that is, a direction along the left-right direction is a left direction (direction of arrow D1 shown in FIGS. 1 and 3) and a right direction (FIG. 1 and the direction of arrow D2 shown in FIG. 3).

The steering wheel body 2 is
A rim portion 5 as a grip portion having an annular shape which is also called a ring portion or a grip;
And a plurality of, in the present embodiment, three spokes 7 connecting the rim 5 and the boss 6 to each other. A substantially cylindrical boss 8 fitted to a steering shaft (not shown) as a steering shaft is provided on a back surface of the boss portion 6, and a boss plate 9 having a plate shape or the like is provided on the boss 8. It is fixed by welding or the like or integrally formed. From the boss plate 9, the core metal 7a of the spoke portion 7 is fixed by welding or the like or is integrally extended, and further, the core metal 5a of the rim portion 5 is welded to the core metal 7a of the spoke portion 7. And are integrally formed.
A soft skin portion 10 made of a synthetic resin or the like is formed on the outer peripheral portion of the core metal 5a of the rim portion 5 and the outer peripheral portion of the core metal 7a of the spoke portion 7 on the rim portion 5 side. I have. In the present embodiment, the boss plate 9 and each of the metal cores 5a and 7a
A magnesium alloy is integrally formed by die casting, and a skin portion 10 made of foamed polyurethane is integrally formed therearound.

A back cover (lower cover) 11 made of resin such as polypropylene is attached to the boss plate 9 using a screw or the like, and the back surface of the boss 6 is covered. An opening 11a through which the boss 8 or the steering shaft is inserted is formed in the center of the back cover 11. Further, an electrical connection device for electrically connecting the vehicle body side and the steering wheel 1 side is attached to the inside or the back side of the back cover 11.

Further, from the boss plate 9, a support boss 12 for abutting and positioning on the back surface of the airbag device 4 is integrally provided so as to face the front side. The boss plate 9 or the core metal 7a of the spoke portion 7 is provided with an airbag device attachment portion for fixing and holding the airbag device 4 integrally or separately.

On the other hand, the airbag device 4 is also referred to as an airbag module, and serves as a center pad of the steering wheel 1 in appearance and is a driver-restricted airbag device activated by a collision or the like. Or FIG.
As shown in FIGS. 2 and 4, in particular, as shown in FIGS. 2 and 4, the airbag device main body 21 is provided, and a plurality of switch devices are provided on the outer peripheral side of the airbag device main body 21, in this embodiment, as three switch devices. The horn switch device (horn switch mechanism) 22 is integrally provided.

The airbag device main body 21 is made of resin which covers a base plate 24 as a base body, a bag-shaped airbag 25 which is folded and stored, and a folded airbag 25 which is attached to the front side of the base plate 24. Cover body 26, an inflator (gas generator) 27 for injecting gas to supply inflation gas to the airbag 25, and holding means for covering the airbag 25 inside the cover body 26, which is also referred to as wrapping or binding band. It is configured by combining a band 28, a retainer (retainer ring) 29 for fixing the airbag 25, the inflator 27, and the like to the base plate 24, and an electrical terminal connection device.

The base plate 24 is an airbag.
25 and an inflator 27, which are formed in an open-box shape with an open front side and are formed integrally by, for example, die-casting a magnesium alloy, and have a substantially polygonal base portion as a base portion. And a polygonal cylindrical peripheral wall portion 24b protruding from the peripheral portion of substantially the entire periphery toward the front side. In the substrate portion 24a, a raised portion 24c which is located at the center and is raised one step toward the front side is formed, and a circular inflator through hole 24d is formed at the center of the raised portion 24c. In addition, bolt through holes 24e are formed at a plurality of locations, in this embodiment four places, on the outer periphery of the inflator through hole 24d.

The inner surface of the peripheral wall portion 24b is
And a plurality of ribs 24f extending in the front-back direction are formed at predetermined intervals. On the other hand, on the outer surface of the peripheral wall portion 24b, a hook portion 24h as an engaging portion whose front end portion is directed toward the rear side is integrally provided at a predetermined interval, and a plurality of spoke portions are provided in the present embodiment. A shelf-shaped fixed contact support 31 as a support constituting the horn switch device 22 is integrally formed at three places protruding toward the 7 side. Each of the fixed contact support portions 31 includes a support plate portion 31a protruding from the peripheral wall portion 24b in a horizontal plate shape, an annular portion 31b provided on the distal end side of the support plate portion 31a, and an annular portion 31b. A through hole 31c provided at the center and a second contact portion fixed to the support plate portion 31a integrally or separately using a rivet made of brass, which is located on one side of the annular portion 31b. And a contact 31d.

Further, a pair of mounting pieces 24k on both sides are projected from the bottom surface of the substrate portion 24a toward the rear side, and each mounting piece 24k is formed with a mounting hole 24m such as a screw hole. ing.

As shown in FIG. 7 and the like, the airbag 25 includes a first base cloth 25a on the vehicle body side and a second base cloth 25b facing the occupant side, each of which has a circular shape. ,
A small-diameter circular third base cloth 25c disposed in an outer shell formed by the 25b, and a plurality or singly, in this embodiment, two, A tether belt 25d as a string is provided, and the third base cloth 25c and the second base cloth 25b are connected by the tether belt 25d. And these base cloths 25a, 25b, 25c
It is also called a plate (lower plate portion, upper plate portion, middle plate portion) or a panel (back panel, front panel, center panel), and is made of, for example, nylon woven cloth. It is a so-called non-coat type base that uses a fiber woven fabric, 350 dtex yarn, and drives 24.4 (62 / inch) per cm in both length and width (longitudinal and weft directions) and is not coated with resin or the like. Uses cloth.

Then, the first base cloth 25a and the second base cloth 25b are integrally sewn along the outer periphery sewn portion 25f of the double chain stitch in a state where they are overlapped. A flat bag-like outer shell is formed by the first base cloth 25a and the second base cloth 25b in a state where the inner and outer sides are reversed and the ears serving as the seam allowance face inward. The first base cloth 25a fixed to the base plate 24 has an inflator serving as a gas introduction portion which is a large circular hole into which the inflator body 27a, which is the upper half of the inflator 27, is inserted at the center. A gas inlet 25g serving as an insertion port is formed with an opening, and is a small circular hole which is located around the gas inlet 25g and into which a mounting bolt (stud bolt) described later of the retainer 29 is inserted. A plurality of circular bolt mounting holes 25h, which are holes, are formed at four locations in the present embodiment, and include an annular mounting portion including these bolt mounting holes 25h and surrounding the gas inlet 25g.
25i are configured.

The third base cloth 25c can be called a gas regulating panel, and has a circular panel part having a smaller diameter than the first and second base cloths 25a and 25b. For example, the gas inlet has a radius slightly larger than half the radius of the first and second base cloths 25a and 25b, is concentric with the first and second base cloths 25a and 25b, and has a gas inlet. It is arranged so as to cover 25 g and the periphery of the gas inlet 25 g.
Further, the third base cloth 25c is provided at a plurality of places near the outer peripheral portion of the third base cloth 25c, in this embodiment, at four places, and the first base cloth 25a is formed only by the joint portion 25k which is a stitching point. Are joined by sewing. In the present embodiment, each joint 25k is substantially airtightly formed by a circular double stitching line (stitch), and surrounds the gas inlet 25g at substantially equal intervals on the circumference, so to speak. They are arranged radially.

The gas introduced from the gas inlet 25g can pass between the outer peripheral portion of the third base cloth 25c and the first base cloth 25a, which is the portion between the joints 25k. And a first base cloth 25a which is an upstream side of the flow passage.
Between the first base cloth 25a and the third base cloth 25c and the second base cloth 25b downstream of this flow passage. It becomes the second branch R2. further,
In one or more of these joints 25k, in the present embodiment, one front side is located inside the joint 25k, and an exhaust port (vent hole) 25m as an exhaust part is opened concentrically. It is formed. That is, this exhaust port
25m communicates from the front side of the third base cloth 25c to the back side of the first base cloth 25a so that the inside air can be discharged from the second compartment R2 to the outside of the airbag 25.

The tether belt 25d for connecting the third base cloth 25c and the second base cloth 25b has a belt-shaped, that is, a belt-shaped belt part having a predetermined width, and the belt part has a third width.
A base belt portion 25n integrally extended from a plurality of places of the base cloth 25c, for example, two places near the upper and lower joints 25k, and a front side belt member 25p sewn to the second base cloth 25b. And the front side belt portion 25q. The front side belt member 25p is formed of, for example, the same material as the other base cloth. Further, one of the base end side belt portions 25n is disposed close to the exhaust port 25m, and in the present embodiment, the outer peripheral side of the exhaust port 25m, that is, the 12:00 direction of the steering wheel 1 (FIGS. 3 and 7). (In the Z-point direction shown in FIG. 3).

In this embodiment, the tether belt
In 25d, the width of the belt part is larger than the diameter of the opening part of the exhaust port 25m, and in the state where the airbag 25 is folded, the belt part substantially covers the exhaust port 25m, suppressing gas leakage at the beginning of deployment Thus, the airbag 25 can be inflated and deployed while using gas efficiently.

The cover body 26 is also called an airbag cover, and is integrally formed of a synthetic resin, for example, by injection molding an elastomer (TPO).
A horn switch device 22 mounted on each fixed contact support portion 31 of the base plate 24 is supported so as to be able to move back and forth in the front and rear directions. The cover body 26 covers a part of the boss portion 6 and the spoke portion 7 of the steering wheel body 2 and has a curved plate-shaped covering portion 26a as a cover plate portion which forms an appearance as a center pad of the steering wheel 1. A substantially rectangular cylindrical side wall portion (peripheral wall portion) 26b protruding from the back surface to the back surface of the covering portion 26a is provided. And
The portion surrounded by the covering portion 26a and the side wall portion 26b and the base plate 24 attached to the back side of the cover body 26 becomes an airbag storage portion for storing the folded airbag 25, and the airbag storage portion Facing, covering part
A tear line 33, which is a line to be broken as a portion to be broken, is linearly formed as a thin groove, that is, a groove to be broken, which is a fragile portion, on the back surface, that is, the back surface of 26a. An emblem (nameplate) 34 of a substantially rectangular shape or the like is integrally or separately attached to the front surface of the covering portion 26a so as to be flush with the surface of the covering portion 26a.

As shown by the broken line in FIG. 1, the tear line 33 is provided on the facing portion 35 facing the occupant of the covering portion 26a, and includes a center tear line 41 as a first line to be broken and a second tear line. Upper tear line 42 as a line to be broken
An upper tear line 43 as a third break line, and a pair of inclined tear lines 4 on both sides as a fourth tear line
4, 44 are formed continuously with each other. The center tear line 41 extends substantially in the vertical center of the opposing portion 35 in both side directions and is formed in a substantially linear shape when viewed from the front. Further, the upper tear line 43 is formed substantially in parallel with the center tear line 41 so as to draw a gentle arc (arch) along the upper edge of the facing portion 35. Furthermore, the upper tear line 42
It extends upward from the center tear line 41 and extends vertically so as to connect the center portions of both sides of the center tear line 41 and the upper tear line 43 with each other.
It is formed around 34. Also, each inclined tear line
44 is formed by drawing a gentle arc along the periphery of the facing portion 35 and extends upward from the terminals on both sides of the center tear line 41, and an upper inclined tear line 44a, and from the terminals on both sides of the center tear line 41 downward. And a lower inclined tear line 44b extending therefrom. Further, at the terminal portions of the upper tear line 42 and each of the inclined tear lines 44, a spreading portion 46 having a shape of being wrapped in a substantially J-shape is formed inside the facing portion 35. A portion between the extending portions 46 constitutes a hinge portion, and a pair of upper side hinge portions 47, 47 on both sides and a lower hinge portion are formed.
48.

While the thickness dimension of the facing portion 35 of the covering portion 26a, that is, the general plate thickness is 4 mm, the plate thickness at the position where the tear line 33 as the groove is provided is 0.1 mm smaller than the general plate thickness. It is set to about 6 mm.

The tear line 33 is an airbag.
As shown in the imaginary line of FIG. 1 and FIG. 6, a plurality of door portions, in this embodiment, the door portions in this embodiment, A pair of upper side doors 51, 51 on both sides constituting an upper door
Then, the lower door part 52 constituting the door part rotates and unfolds to form a projecting opening of the airbag 25.

That is, the upper door is a center tear line.
41, an upper tear line 42 and a center tear line formed upward from the midpoint of the center tear line 41.
The upper tear line 43 formed in parallel with 41 forms a left and right division.

The upper doors 51, 51 constituting the upper door formed above the center tear line 41 and the lower door 52 formed below the center tear line 41 are combined. The shape, that is, the facing portion 35 has a substantially square shape, and the upper door portion is divided into right and left at a substantially central portion. On the other hand, with respect to the vertical dimension, the center tear line 41 is deviated downward so that the lower door 52 is smaller than the upper door 51 by a predetermined range. That is, the dimensional ratio L1: L2 of the upper door portions 51, 51 and the lower door portion 52 in the vertical direction.
Is set in the range of 55:45 to 70:30, and in the present embodiment, the dimensional ratio L1: L2 is set to be a ratio of 6: 4.

On the other hand, a notch 26g is formed in the side wall 26b of the cover body 26 and communicates with a lower end of the cover 26 toward the three spokes 7, and a predetermined distance is provided between the notches 26g. An engagement receiving portion 26h, which is a through hole having a rectangular shape or the like, is formed. Further, a movable contact supporting portion 55 constituting the horn switch device 22 is provided on the back surface of the covering portion 26a, which is located on the spoke portion 7 on the outer peripheral side of the side wall portion 26b, as shown in FIG. Brackets 56 are attached to the movable contact support portions 55, respectively. As shown in FIGS. 2 and 4, each bracket 56 is formed by integrating an insulating portion 56c made of a resin having an insulating property with a plate portion 56b made of a steel plate having a movable contact 56a.
A coil spring 57, which is an elastic body and a spring, serving as an urging means, and a screw 58, which is a fixture and constitutes a support shaft, are attached to the insulating portion 56c of the bracket 56. Although not shown, a terminal connecting device is electrically and mechanically connected to the plate portion 56b of the bracket 56, and the movable contact 56a is connected by the terminal connecting device.
Are electrically and mechanically connected to a connection device for electrically connecting the vehicle body side and the steering wheel 1 side.

Note that FIG. 2 shows only the position of the lower spoke portion 7, but the inside of the other two spoke portions 7 located on the left and right sides, that is, the airbag device 4 side is similarly provided. The horn switch device 22 is attached, and the side wall 26
The horn operation is enabled by supporting the cover body 26 at three places outside of b and pushing and moving the cover body 26 forward and backward.

The inflator 27 has a base plate
An inflator body (container) 27a having a substantially cylindrical shape and filled with a propellant or the like is provided on the front side of the inflator body 27a, and a gas injection port is provided at a predetermined interval in a circumferential direction. 27b is formed, and a flange portion 27c is protruded from a substantially central portion in the height direction of the inflator main body 27a on the outer peripheral side, and the flange portion 27c has
Bolt through holes 27e are formed in four places. A lead wire 27f and the like are led out from the bottom of the inflator main body 27a, and power for starting is supplied via a connector 27g attached to the tip. Note that a protector integrally formed of a synthetic resin or the like can be fitted to the bottom of the inflator body 27a.

Further, as shown in FIG. 4 and FIG. 5, the band 28 holds the folded airbag 25 in a folded state and holds the folded shape. The same nylon 66 as the base cloth constituting the airbag 25 is used. It is formed with a base cloth made of.
The band 28 has a band shape, and a guide breakable portion 28a extending in the width direction is formed at the center in the longitudinal direction. The guide rupture expected portion 28a can be called an opposing portion, and has a narrow connecting portion 28b provided at a central portion in the longitudinal direction and the width direction of the band 28, and a pair of opposite sides defining the connecting portion 28b. Are provided on a straight line orthogonal to the longitudinal direction. The band 28 has attachment portions 28d, 28d, which are terminal portions, respectively, formed at both ends in the longitudinal direction. Each mounting portion 28d includes a pair of mounting pieces 28e, 28e on both sides. Each mounting piece 28e has a circular through hole 28f, and a pair of mounting pieces 28e, 28e.
An arch 28g for avoiding the inflator 27 is provided between 28e.

Then, the band 28 is wrapped around the front side of the folded airbag 25 in both sides to maintain the shape of the airbag 25.

In this embodiment, the width of the band 28 is 100 mm, the connecting portion 28b is located at the center in the width direction, and the dimension of the connecting portion 28b along the width direction of the band 28, that is, the length is Although the dimensions were set to 5 mm, these dimensions and the position of the connecting portion 28b were determined based on the strength of the base cloth used for the band 28,
In addition to the desired deployment characteristics, that is, the overall deployment time of the airbag 25, and the deployment delay time of the portion suppressed by the connecting portion 28b with respect to the other portions, it is appropriately set.

The retainer 29 presses the airbag 25 from the inside and attaches it to the base plate 24. The retainer body 29a is an annular metal retainer body 29a having a rectangular outer shape and a substantially circular inner shape. And a plurality of mounting bolts (stud bolts) 29b fixed to 29a. The through hole on the inner periphery of the retainer main body 29a has substantially the same shape as the inflator through hole 24d of the base plate 24, and the mounting bolt 29b is connected to the bolt through hole 24e of the base plate 24 or the like.
Is formed.

To assemble the airbag apparatus 4 having these members, first, the retainer 29 is inserted into the inside of the airbag 25 from the gas inlet 25g, and each mounting bolt 29b of the retainer 29 is used for the bolt of the airbag 25. It is inserted into the through hole 25h and exposed to the outside. Then, the airbag 25 and the retainer
29 is mounted on an airbag folding device, and the airbag 25 is folded into a predetermined shape such as a petal shape. And airbag
The band 28 is put on the band 25, and the through holes 28f of the band 28 are passed through the mounting bolts 29b to be locked, so that the folded shape of the airbag 25 is maintained to be a semi-finished airbag product. In this state, the guide rupture expected portion 28a vertically crosses the central portion of the front side of the airbag 25 on both sides in the vertical direction, and the connecting portion 28b is aligned with the central portion of the airbag 25 on the front side.

Next, this semi-finished airbag product is inserted and accommodated in the peripheral wall portion 24b of the base plate 24, and the side wall portion 26b of the cover body 26 in which the bracket 56 and the coil spring 57 are attached to the movable contact support portion 55 in advance. Is fitted over the outer peripheral side of the peripheral wall portion 24b of the base plate 24 from the front side. At this time, each hook part 24h of the base plate 24
Into the engagement receiving portion 26h of the cover body 26 so as to be able to advance and retreat in the front and rear directions within a predetermined range, and
The cover is strong enough to hold the cover 26 even when the
Hold 26. In this state, the coil spring 57
Is pressed by the annular portion 31b of the fixed contact support portion 31, and the screw 58 inserted from the back side of the through hole portion 31c is screwed into the bracket 56, whereby the horn switch device 22 is assembled. In this state, the movable contact 56a of the bracket 56 and the fixed contact 31d of the base plate 24 face each other, are separated from each other by a predetermined dimension by the urging force of the coil spring 57, and are held in an insulated state.

Further, through the inflator through hole 24d of the base plate 24 and the gas inlet 25g of the airbag 25,
The front side portion of the inflator 27 is inserted into the airbag 25, and the mounting bolts 29b of the retainer 29 are inserted into the bolt holes 27e of the flange portion 27c, and tightened from below with a nut (not shown). In this state, the first base cloth 25a of the airbag 25 is placed between the retainer 29 and the inflator 27.
And the base plate 24 are fastened together, and the airbag device 4
Is assembled.

The airbag device 4 is mounted on the steering wheel 1 by fixing the mounting piece 24k provided on the base plate 24 to the core of the steering wheel main body 2 using bolts or the like (not shown). And
In this state, the movable contact 56a is connected to a connection device that electrically connects the vehicle body side and the steering wheel 1 side via a terminal connection device. The fixed contact 31d is connected to the plus circuit, and is connected to the vehicle body (earth) via, for example, the base plate 24, the boss 8, the steering shaft, and the like.

Therefore, when no force is applied to the cover body 26 of the airbag device 4, the horn switch device 22 pushes up each bracket 56, that is, the cover body 26 by the urging force of each coil spring 57, and moves the movable contact 56a. And the fixed contact 31d are held facing each other at a predetermined interval. On the other hand, when the cover 26 of the airbag device 4 is pushed against the urging force of each coil spring 57, the cover 26 is engaged with the engagement receiving portion 26h of the cover 26 and the hook 24h of the base plate 24.
Move to the rear side with the engagement part with
When a contacts the fixed contact 31d, the circuit closes and the horn blows.

In the present embodiment, the horn switch device 22 is provided with hook portions which engage with each other during a normal pushing operation in order to improve the operational feeling by eliminating the so-called bottom feeling.
24h and the engagement receiving portion 26h are on the front side and the back side, for example, 0.
It is set to leave a slight gap of about 3 mm to 0.5 mm.

When a collision impact is applied to the vehicle equipped with the airbag device 4, the inflator 27 is activated by a control unit (not shown), and the gas is rapidly injected into the airbag 25 from the gas injection port 27b of the inflator 27. Is injected. Then, the airbag 25 breaks the band 28 along the guide break scheduled portion 28a and breaks the cover body 26 along the tear line 33 to rotate each door portion 51, 51, 52 to form a projecting opening. Then, the occupant is inflated and deployed through the projecting opening, swells in a predetermined shape on the front side of the occupant, receives and restrains the occupant thrown forward, and reduces the impact applied to the occupant.

Next, the cover body when the airbag 25 is deployed
The operation of 26 and band 28 will be described in detail.

The deployment of the airbag 25 itself is an operation that takes place in a very short time of about 0.3 seconds after the activation of the inflator 27. Immediately after activation of the inflator 27, that is, immediately after gas is supplied to the inside of the airbag 25, the airbag 25 is
Although it expands freely at the part facing c, the connecting part 28b
Since it is necessary to cut the connecting portion 28b at the portion facing the notch 28, the expansion is slightly delayed as compared with the upper and lower portions facing the cutout portion 28c.

Then, the tear lines 41, 42, 43, 44 and 44 are broken by the pushing up of the airbag 25,
Each door part 51,51,52 is formed. That is, the center tear line 41 is stretched back and forth and breaks, and furthermore, the inclined tear lines 44 and 44 on both sides are broken to form a lower door portion 52 having a hinge portion 48 on the lower side.
42 is extended to both sides and fractured, and the upper tear line 43 is further fractured to form upper side door parts 51 and 51 having hinge parts 47 and 47 on both sides, respectively. At this time, the band
As shown by a two-dot chain line II in FIG. 7, the connecting portion 28b of the air bag 25 has a small dimension in the front and rear direction at the center, that is, a height dimension, and is expanded so as to expand flatly in all directions. I do. Next, as shown by a two-dot chain line III in FIG. 7, the height dimension of the peripheral portion is increased by the gas flowing to the peripheral portion with almost no change in the height dimension of the central portion. The expanded shape of. And, although not shown, at this moment of this momentary operation, the tether belt 25d is not extended, folds over the exhaust port 25m, and blocks gas leakage from the exhaust port 25m to the outside of the airbag 25. Acts as a pressure regulator. Thereafter, the tether belts 25d, 25d are expanded with the expansion of the central portion, and the second base cloth 25d is expanded.
With the protrusion of the center part of b in the front side restricted, the so-called full deployment is achieved, and the tether belt 25d is
The air outlet 25m is opened at a distance from 5m, and the occupant as a protected object falling down is received to reduce the impact.

As described above, according to the present embodiment, with respect to the door portion formed by inflating and deploying the airbag 25, the upper side door portion 51 located on the upper side is located at the base of the spoke portions 7 on both sides. The upper side hinge portion 47 formed along the vertical direction along the longitudinal direction rotates as a hinge. Therefore, the upper door does not have a rotation locus above the airbag device 4, more specifically, in the space E in front of the facing portion 35 of the cover body 26, that is, the upper tear line 43. That is, since the upper door portion is divided into two right and left parts, the maximum point in the front direction of the rotation trajectory is formed lower in the front-rear direction. In this manner, the trajectory of any of the doors is set low with respect to the occupant, that is, the driver of the vehicle, which is the object to be protected. Therefore, favorable deployment characteristics can be obtained for various aspects of the positional relationship between the airbag device 4 and the object to be protected.

Further, in this embodiment, the airbag
Since the 25 exhaust ports 25m are arranged at the position of 12 o'clock, which is the upper side, the upper side door portion 51 which opens in the direction of 9 o'clock and 3 o'clock on both sides does not participate in the exhaust operation at all. That is, since the position of the exhaust port of the airbag is shifted from the position of the opening direction of the door portion of the cover body, the adjustment of the exhaust characteristic can be easily performed.

Further, the folded airbag 25 is provided with a band.
Although the shape is held by the airbag 25, when the airbag 25 is inflated and deployed, first, the airbag 25 is inflated at the upper and lower cutouts 28c, 28c, and then the narrower connecting portion 28b
And expand it. For this reason, in the airbag 25, the side portions of the band 28 in the longitudinal direction, that is, the portions located above and below are inflated in advance, and the inflation height of the central portion can be suppressed. Thus, the guide rupture scheduled portion 28a provided in the band 28
Thereby, the deployment characteristics of the airbag 25, that is, the deployment shape over time, that is, the deployment direction of the airbag 25 and the delay of deployment of each part can be easily adjusted.

Further, the present invention relates to a steering wheel with an airbag device attached to a vehicle such as an automobile, and particularly to a configuration provided with a switch (horn switch) for pressing a portion of the airbag device 4 to activate a horn or the like. Since only the cover body 26 is moved forward and backward instead of moving the entire device 4 forward and backward, the urging force of the coil spring 57 as the urging means can be reduced, and the operational feeling of the horn switch device 22 can be easily improved. In this configuration, the cover body 26 moves with respect to the airbag 25 attached to the base plate 24 when the horn is operated.
The airbag 25 is stored in a box-shaped base plate 24,
Further, since the front side is covered and bound by the band 28, the sliding contact between the cover body 26 and the airbag 25 can be prevented to protect the airbag 25, and the folded shape of the airbag 25 can be securely held. At a desired position.

It should be noted that the tear line, which is the portion to be broken, can have another arrangement, for example, a tear line that can be broken can be added. For example, the second breakable line portion may be extended not only above but also below the first breakable line portion, and the lower door portion may be opened right and left.

For example, as shown in FIG. 8, the second breakable line is formed by connecting the upper tear line 42 extending above the center tear line 41 as the first breakable line to the center tear line 41. Or a lower tear line 61 extending downward from a different position. further,
In this configuration, a lower tear line 62 extending in both directions along the lower end of the facing portion 35 is formed continuously with the front end portion, that is, the lower end portion of the lower tear line 61. Further, at the terminal portion of the lower tear line 62, as in the case of the other tear lines, a spreading portion 46 is formed which is formed in a substantially J-shape around the inside of the facing portion 35, respectively. Also, the inclined tear lines 44 on both sides
The lower inclined tear line 44b extending downward is formed to have the same length as the upper inclined tear line 44a, that is, shorter than the embodiment shown in FIG. Then, by breaking the tear lines, the lower door portion can be divided into a plurality of portions, and the lower side door portions 64, 64 that open left and right can be formed using the lower side hinge portions 63, 63 as hinges.

The band 28 may be formed of a base material similar to the airbag 25, or may be formed of a sheet material such as a resin-impregnated paper or a plastic film such as PET. Although the connecting portion 28b has a single continuous shape, the connecting portion is divided into a plurality of connecting portions by a single or a plurality of cutouts, and the cutout portions 28c and 28c It can also be a connection part substantially. Further, the folded airbag 25 may be formed in a bottomless box shape having a peripheral wall portion extending from the periphery of the front portion covering the front side to the rear side. In addition, this band 28
Can be passed over the airbag 25 in both directions, and can also be passed up and down. Further, the band 28 can be attached with a double-sided adhesive tape or the like, in addition to locking the through hole 28f to a mating member.

In the above embodiment, the airbag 25
The cover 28 is suitable for a configuration in which the cover 26 moves with respect to the base plate 24 and the airbag 25 attached to the base plate 24 when the horn is operated. An appropriate configuration can be adopted for the configuration of the horn switch mechanism. For example, the cover body may be fixedly attached to the base plate using a belt made of rivets or metal, and the entire airbag device may be supported by a horn switch device so as to be able to advance and retreat.

Further, the airbag is not limited to a so-called 2.5-layer type airbag in which a third base cloth having a smaller diameter than the other base cloth constituting the outer shell is housed in the outer shell. The present invention can also be applied to a three-layer type airbag in which the outer peripheries of three base cloths are integrally stitched, an airbag using two base cloths, and the like.

The airbag device is used not only for the driver attached to the steering wheel body, but also for the occupant in the front passenger seat provided on the instrument panel, for protecting the side portion provided on the side of the seat, or for the rear portion of the seat. The present invention can be widely applied to an airbag of an airbag device for a rear seat provided in a vehicle, and further to an airbag of an airbag device that absorbs an impact of an object to be protected.

[0064]

According to the airbag device of the first aspect, for the plurality of door portions formed by breaking the portion to be broken, the upper door portion whose vertical dimension is larger than that of the lower door portion is provided. A pair of upper side doors on both sides are defined by the second scheduled break line portion and the third scheduled break line portion, and are expanded laterally. By reducing the size, deployment characteristics can be easily improved.

According to the airbag device of the second aspect,
In addition to the effect of the first aspect, the size and direction of the rotation trajectory of each door can be appropriately set, and the deployment characteristics can be easily improved.

According to the airbag device of the third aspect,
In addition to the advantageous effects of the first or second aspect, the deployment direction of the airbag is guided by the guide breakable portion of the holding means, which is a member that holds the folded shape and facilitates assembly of the airbag device, and facilitates deployment characteristics. Can be improved.

According to the airbag device of the fourth aspect,
In addition to the effect of the third aspect, in the airbag, the peripheral portion facing the notch portion of the holding means is deployed, and then the connecting portion is broken and the central portion is deployed. Suitable deployment characteristics for quickly deploying can be easily realized. The configuration is simple, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of an airbag device of the present invention.

FIG. 2 is a sectional view of the steering wheel provided with the airbag device, taken along the line II of FIG. 3;

FIG. 3 is a perspective view showing the airbag device.

FIG. 4 is an exploded perspective view showing the airbag device.

FIG. 5 is a perspective view in which a part of the airbag device is cut away.

FIG. 6 is an exploded perspective view showing only a base plate and a cover body of the airbag device.

FIG. 7 is a sectional view showing an operation of the airbag device.

FIG. 8 is a perspective view showing another embodiment of the airbag device of the present invention.

[Explanation of symbols]

 4 Airbag Device 25 Airbag 26 Cover Body 28 Band as Holding Means 28a Guide Breakage Part 28b Connecting Part 28c Notch 33 Tearline as Breakage Part 35 Opposed Part 41 Center Tearline as First Plane Breakage Line 42 Upper tear line as the second scheduled break line 43 Upper tear line as the third scheduled break line 51 Upper door 52 Lower door

Claims (4)

[Claims] An airbag that is inflated and deployed by supplying a gas, is formed by a rupture portion that covers the airbag when not inflated and ruptures by a pressure at which the airbag is inflated, and rupture of the rupture portion. A cover body having a plurality of doors and an opposing portion facing the object to be protected, wherein the scheduled breaking portion is a first scheduled breaking line portion extending in both sides, and the first scheduled breaking is provided. A second breakable line extending upward from an intermediate portion of the line, and a second line extending to both sides substantially along the first line of break that is continuous with the distal end of the second line of breakage. 3, a first scheduled break line portion, the first scheduled break line portion divides an upper door portion and a lower door portion constituting the door portion, and a second scheduled break line portion and a third scheduled break line line The section defines a pair of upper side door sections constituting the upper door section, The dimensions of the side door portion, an airbag apparatus characterized in that it is set larger than the dimension of the lower door portion in the vertical direction. 2. A combination of an upper door portion and a lower door portion has a substantially square shape, and a second breakable line section divides the upper door portion at a substantially center in both sides, and a vertical line in the vertical direction. The dimensional ratio between the upper door portion and the lower door portion is 55:45.
The airbag device according to claim 1, wherein the airbag device has a range of 70 to 30. 3. A holding means provided with a guide rupture portion for wrapping the airbag when not inflated and holding the folded shape and guiding the direction in which the airbag inflates and deploys when ruptured. Item 3. The airbag device according to item 1 or 2. 4. The guide rupture portion of the holding means includes a connecting portion provided at a central portion in the longitudinal direction, crossing the holding means, and cutout portions continuous to both ends of the connecting portion. The airbag device according to claim 3, wherein