JP2000272454A - Air bag door - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deterioration of appearance quality in a design surface of an air bag door after it is left as it is at a high temperature and ensure rigidity of a door end part. SOLUTION: In this air bag door 10 provided with a burst part 7 of thin shape broken by an extending pressure of an air bag, a protrusive streak 16 protruded from a door reverse surface to be mutually opposed to a rack surface 8b of a drop-in part 8 is provided in a position in an internal peripheral side by the prescribed dimension A from a peripheral side surface 14 of an end part, in the end part 12 of a peripheral edge of the door arranged in the drop-in part 8 in an opening edge part of an instrument panel 1, and the end part 12 is formed in an almost T-shaped section. In this way, a contact area of the end part 12 abutting to a side surface 8a of the instrument panel 1 at the time left at a high temperature is decreased, stress F acting in a door central part is absorbed between the end part 12 and a door wall 5 by such a contact, and stress acting on the burst part 7 is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag door used in an airbag apparatus for protecting an occupant by inflating and deploying an airbag in a vehicle compartment at the time of a vehicle collision.

[0002]

2. Description of the Related Art In general, an airbag door is provided with an airbag on the rear side and is pushed open by the inflation pressure of the airbag, and the airbag is opened from an opening formed thereby. It swells into the vehicle compartment.

FIGS. 3 to 5 show an example of a conventional structure of such an airbag door. FIG. 3 is a perspective view of an instrument panel 1, and FIG. 4 is a cross-sectional view taken along line IV-IV of FIG. FIG. 5 and FIG. 5 are enlarged sectional views of the terminal portion 101 of the airbag door 100.

[0004] The airbag door 100 is disposed so as to close an opening provided at a position corresponding to a passenger seat of an instrument panel 1 which is a vehicle interior body, and is folded at the rear side. A case 4 for housing the airbag 2 and the inflator 3 is provided. A door wall 5 attached to the side of the case 4 protrudes from the back surface of the door, and the door wall 5 is fixed to the case 4 by fixing means 6 such as bolts.
The airbag door 1 is attached and fixed to the outer surface of the airbag door 1.
00 is configured to cover the upper opening of the case 4. Note that the door wall 5 is usually provided circumferentially so as to surround the entire side surface of the case 4.

[0005] In the door portion on the inner peripheral side of the door wall 5, a thin-walled breaking portion 7 that is broken by the inflation pressure of the airbag 2 is provided by providing a groove on the back surface of the door. When the airbag 2 breaks, the airbag 2 is inflated and deployed from inside the instrument panel 1 into the vehicle interior. As shown in FIG. 3, the break portion 7 includes a pair of left and right vertical break portions 7a, 7a extending in the vehicle front-rear direction relative to the vehicle width direction, and a transverse break portion extending in the vehicle width direction connecting these central portions. 7b. In addition, the horizontal breaking part 7b is replaced with the vertical breaking part 7a,
In some cases, a U-shaped break 7 is provided by connecting the rear end of the vehicle 7a.

[0006] In the assembly structure of the airbag door 100 and the instrument panel 1, an opening edge of the instrument panel 1 is dropped downward, and a terminal portion 101 on the periphery of the door is disposed in the recess 8. Thus, the terminal unit 101 is configured to be surrounded by the side surface 8a of the drop unit 8. Reference numeral 102 denotes a hook that protrudes from the rear surface of the terminal unit 101 of the airbag door 100 and locks the terminal of the drop unit 8.
A plurality of airbag doors 100 are provided at appropriate intervals in the circumferential direction.

The airbag door 100 having such a broken portion 7 is usually made of a thermoplastic elastomer, and is therefore made of a resin material different from the instrument panel 1 made of a general-purpose resin such as PP. Is done.
Therefore, in the above-described assembly structure, when the temperature is returned to normal temperature after being left at a high temperature for a long time, a difference in a linear expansion coefficient due to a difference in a resin material constituting the instrument panel 1 and the airbag door 100 is caused. The airbag door terminal 101 interferes with the opening edge of the instrument panel 1, causing deformation in the breakage portion 7, which is the weakest portion of the airbag door 100. The appearance quality of the design surface may be deteriorated.

More specifically, as shown in FIG. 5, the terminal portion 101 of the airbag door 100 is bent downward so as to have a cross section L by taking into consideration the balance between the terminal portion floating prevention and rigidity. It is formed in a character shape. However,
In this case, the peripheral side surface of the terminal portion 101 becomes larger as indicated by the height h by the downwardly extending portion 103, and therefore,
At a high temperature, the contact area between the recess 8 and the side surface 8a increases. Therefore, the contact with the side surface 8a causes the door 1
The stress F acting on the 00 central part increases, causing local deformation at the fractured part 7. In particular, the lower extension 103
Between the door wall 5 and the plurality of ribs 1 so that the
In the case where the terminal unit 101 is reinforced by connecting at 04,
A larger stress F will act.

Such a phenomenon similarly occurs in the structure shown in FIG. In the conventional structure shown in FIG. 6, the terminal portion 1 on the vehicle rear side of the substantially rectangular airbag door 100 is provided.
In 01a, the door 100 is supported not by the instrument panel 1 but by other components 9 attached to the instrument panel 1, such as a center cluster and a lid of a tray box. In this case, the terminal portion 101a on the vehicle rear side of the door 100 has a ridge 105 projecting outward.
Is provided, and the opening edge 9a of the other component 9 is
Is formed in a concave shape in cross section so as to fit with. As described above, when the airbag door 100 is disposed in the opening formed by the instrument panel 1 and the other component 9, since the resin materials of these three members have different linear expansion coefficients, the cooling-heat The appearance quality of the airbag door 100 may be more significantly reduced due to the difference in the shrinkage level between the times.

Conventionally, in order to solve such a problem,
The gap g between the terminal portion 101 of the airbag door 100 and the side surface 8a of the instrument panel 1 is set large to reduce the stress F generated due to interference with the instrument panel 1. However,
Setting a large gap g is not preferable in appearance quality.

Therefore, the present invention prevents the deterioration of the appearance quality of the design surface of the airbag door after being left at a high temperature assuming the state of the vehicle, and reduces the rigidity of the door terminal portion without accompanying these problems. The purpose is to secure.

[0012]

SUMMARY OF THE INVENTION An airbag door of the present invention closes an opening provided in an interior body of a vehicle compartment for housing an airbag device at a rear side thereof, and uses an inflation pressure of an airbag of the airbag device. A door that is pushed open and swells the airbag into the vehicle compartment from an opening formed by the door wall, the door wall protruding from the rear surface of the door and attached to a side surface of a case that stores the airbag; An opening edge of the vehicle interior body is dropped to the rear side of the airbag door, the opening being provided inside the door wall and having a thin-walled break portion that breaks due to the inflation pressure of the airbag. A terminal portion on the periphery of the door is disposed in the portion, and the terminal portion includes
A ridge projecting from the rear surface of the door at a position on the inner peripheral side by a predetermined dimension from the peripheral side surface is provided so as to be opposed to a shelf surface of the recessed portion, whereby the terminal portion has a substantially T-shaped cross section. It is characterized by.

Here, the vehicle interior includes an instrument panel disposed on a front portion of the vehicle interior, and other components attached to the instrument panel such as a center cluster and a lid of a tray box.

[0014] By making the end portion of the airbag door substantially T-shaped in cross section as described above, when left at a high temperature, the side surface of the recessed portion of the vehicle interior is in contact with the outer peripheral side of the ridge. And the contact area with the vehicle interior is smaller than that of the conventional L-shaped section. By forming the contact area into a substantially T-shaped cross section as described above, the stress generated due to the contact with the vehicle interior can be absorbed by the portion on the outer peripheral side of the ridge, and is formed inside the door wall. The stress acting on the thin-walled broken portion can be reduced.

When the door terminal is pressed down from the surface of the door, the ridge formed so as to protrude toward the shelf surface of the recessed portion of the passenger compartment interior body is engaged with the shelf surface to lock. Therefore, the feeling of rigidity of the door terminal portion can be prevented, and the pecking feeling of the terminal portion can be prevented.

[0016] In the airbag door of the present invention, a gradually changing thin portion is formed on the inner peripheral side of the ridge, the thickness being gradually reduced toward the outer peripheral side with respect to the thickness near the door wall. preferable. By providing such a gradually changing thin portion,
Since the stress generated when left at a high temperature can be released in the direction perpendicular to the door surface, the stress absorption between the door terminal portion and the door wall can be more effectively achieved.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing a structure around a terminal portion 12 of an airbag door 10 according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of the terminal portion 12 of the airbag door 10.

The airbag door 10 of this embodiment is a door for an airbag device for a passenger's seat, similar to the above-mentioned prior art.
This is the same as the conventional structure shown in FIGS. That is, the airbag door 10 is arranged so as to close the opening provided in the instrument panel 1, and on the rear side,
A case 4 for storing the folded airbag 2 and the inflator 3 is provided. On the rear surface of the door, a door wall 5 which is attached and fixed to the outer surface of the case 4 by fixing means 6 such as a bolt is projected, and a door portion on the inner peripheral side of the door wall 5 inflates the airbag 2. A thin break portion 7 that breaks by pressure is provided. The opening of the instrument panel 1 has its opening edge stepped downward in a step-like manner, and the terminal part 12 on the periphery of the door is arranged in the depression part 8, whereby the terminal part 12 is It is configured so as to be surrounded by the side surface 8a of the drop portion 8.

As shown in FIG. 1, the recessed portion 8 for receiving the terminal portion 12 of the airbag door 10 is formed in a shape bent downward from the design surface of the instrument panel 1 into an L-shaped cross section. And a shelf surface 8b which is dropped from the instrument panel surface and is substantially parallel to the surface, and a side surface 8a which is an upright surface connecting the shelf surface 8b and the instrument panel surface.

In the airbag door 10 of the present embodiment, the terminal portion 12 is formed in a substantially T-shaped cross section as shown in FIGS. That is, the terminal portion 12 is provided with the protrusion 16 protruding from the rear surface of the door at a position on the inner peripheral side by a predetermined dimension A from the peripheral side surface 14. This ridge 16 is used for the instrument panel 1.
Is provided so as to be opposed to the shelf surface 8b of the drop portion 8 described above. By providing the ridge 16 in this manner, the outer ridge 18 having a surface flush with the door design surface and projecting toward the side surface 8a of the recess 8 is provided on the outer peripheral side. A terminal portion 12 having a substantially T-shaped cross section is formed together with a portion on the inner peripheral side of the ridge 16.

Here, the thickness T1 of the ridge 16 is set smaller than the width W of the shelf surface 8b of the recess 8 (T
1 <W), and is set smaller than the thickness T0 near the door wall 5 (T1 <T0) in order to prevent sink marks on the door design surface when the airbag door 10 is formed. Further, in this embodiment, the lower surface of the projecting ridge 16 is received by the shelf surface 8 b of the lower surface of the recess 8.
Is extended to the inside of the inner peripheral side surface of the ridge 16. The above-mentioned dimension A corresponding to the protruding length of the outer peripheral ridge portion 18
Is determined by the relationship between the width W of the shelf surface 8b and the thickness T1 of the ridge 16, but in order to effectively achieve the effect of absorbing the stress F described later, the thickness is equal to or slightly larger than the thickness T1 of the ridge 16. Set to a large degree.

As shown in FIG. 2, the terminal portion 12 is formed in an arc-shaped cross section by chamfering the design surface side of the outer peripheral ridge portion 18. By the way, this airbag door 10
Is formed by injection molding of a thermoplastic elastomer using an injection mold comprising an upper mold for molding the door design surface side and a lower mold for molding the door back side. In this case, the upper mold and the lower mold are used. Corresponds to the projection angle α of the door wall 5 with respect to the rear surface of the door (see FIG. 1). And the position of the mold mating surface between the upper mold and the lower mold is determined by this mold removal angle,
As shown in FIG. 2, the position PL of the mold matching surface is located below the lower end of the design R of the outer peripheral ridge 18 in order to prevent the occupant from seeing the position PL when assembled to the instrument panel 1. Is preferred. Further, in order to enable the upper die to be die-cut, the lower end of the outer peripheral ridge portion 18 is positioned below the position PL of the die-matching surface, that is, the die-matching surface PL is formed in the peripheral side surface 14. It is necessary to set the thickness (dimension in the height direction) H of the outer peripheral ridge portion 18 so as to be located.

On the inner peripheral side of the ridge 16, there is provided a gradually changing thin portion 20 whose thickness is gradually reduced toward the outer peripheral side with respect to the thickness T0 near the door wall 5. Slowly changing thin part 20
Is formed by providing an inclined surface on the rear surface side of the door such that the thickness becomes thinner toward the outer peripheral side, and the inner peripheral edge 20a of the gradually changing thin portion 20 is formed by the terminal portion 12 and the door wall 5. And the outer peripheral edge 20 b is set at the base position on the inner peripheral side of the ridge 16. Then, the edge 20 on the outer peripheral side where the thickness is the thinnest in the gradually changing thin portion 20
The thickness T2 of b is set to be sufficiently larger than the thickness at the break portion 7. In consideration of the deformation at the break portion 7, it is preferable not to provide a reinforcing rib as described in the related art in the region of the gradually changing thin portion 20.

It should be noted that in FIGS.
4 does not show a hook that projects from the back of the door and hooks the terminal of the drop-in portion 8, but as in the conventional structure shown in FIG. May be provided at intervals.

According to the shape of the terminal portion 12 of the airbag door 10 of the present embodiment, the outer side protruding portion 18 on the outer peripheral side of the protruding portion 16 comes into contact with the side surface 8a of the instrument panel 1 when left at a high temperature. Since the height H of the peripheral side surface 14 is smaller than that in the case of the conventional L-shaped cross section, the contact area with the side surface 8a is smaller. Preferably, the height H of the peripheral side surface 14 is smaller than the thickness T0 near the door wall 5. As described above, the terminal section 12 is connected to a section T having a small contact area.
The stress F generated due to the interference with the side surface 8a can be absorbed by the outer peripheral ridge portion 18 by the letter-shaped shape, and the stress acting on the thin break portion 7 formed inside the door wall 5 can be absorbed. Can be reduced.

Moreover, the gradually changing thin portion 2 is provided on the inner peripheral side of the ridge 16.
0, the stress F generated when left at high temperature
By bending the terminal portion 12 as shown by the two-dot chain line X in FIG. 1, the stress F can be absorbed more effectively because the terminal portion 12 can be released in the vertical direction.

As described above, since the stress F acting toward the central portion of the door which is generated when the door is left at a high temperature can be absorbed between the terminal portion 12 and the door wall 5, the stress F is formed inside the door wall 5. Further, it is possible to suppress local deformation at the fracture portion 7 having the lowest rigidity, and to prevent a deterioration in the appearance quality of the door design surface.

When the terminal portion 12 is pressed down from the door design surface (when a force indicated by an arrow C in FIG. 1 is applied), the ridge 16 facing the shelf surface 8b of the instrument panel 1 is moved. Since the door terminal portion 12 is locked by abutting on the shelf surface 8b, the rigidity of the door terminal portion 12 is not impaired, and the stickiness of the terminal portion 12 can be prevented.

Further, since the terminal portion 12 has a substantially T-shaped cross section, a deterioration in appearance quality when left at a high temperature is prevented, so that a gap between the terminal portion 12 and the side surface 8a of the instrument panel 1 needs to be increased. Therefore, the appearance quality is not deteriorated by the gap. Further, since it is not necessary to increase the thickness of the door general portion and the thickness of the breakable portion 7, there is no problem such as an increase in weight and cost due to an increase in the thickness of the door general portion. Since it is not necessary to increase the wall thickness, the airbag 2 can be smoothly deployed.

In the above embodiment, the terminal portion 12 has a substantially T-shaped cross section over the entire periphery of the door. However, in the present invention, the terminal portion 12 on the entire periphery does not necessarily have to have a substantially T-shaped cross section. . For example, as described in the conventional structure shown in FIG. 6, when the terminal portion 12 on the vehicle rear side of the airbag door 10 having a substantially rectangular shape is supported by other components 9 such as a center cluster and a lid of a tray box. The terminal portion 12 on the rear side of the vehicle may have the same structure as the conventional structure shown in FIG. According to the present invention, such an instrument panel 1 can be easily combined with the third component 9 having a different linear expansion coefficient from the instrument panel 1, and the degree of freedom in design and design is increased. In the case where the terminal portion 12 on the entire circumference is not formed in a substantially T-shaped cross section, the terminal portion 12 on at least one of the opposed sides is provided.
Needs to be substantially T-shaped in cross section.

[0032]

According to the airbag door of the present invention, the terminal portion has a substantially T-shaped cross section, so that the stress acting toward the center portion of the door generated when the door is left at a high temperature is prevented from acting on the door terminal portion and the door wall. Therefore, it is possible to suppress local deformation at a break portion formed inside the door wall, and to prevent a deterioration in appearance quality of the door design surface.

When the door terminal is pressed down from the surface of the door, the ridge opposite to the shelf surface of the recessed portion of the vehicle interior is locked by contact with the shelf surface. The rigidity of the door terminal can be prevented from being impaired, and the stickiness of the terminal can be prevented.

Furthermore, since the terminal portion has a substantially T-shaped cross section, deterioration in appearance quality when left at a high temperature is prevented, so that a gap between the door terminal portion and the interior of the vehicle compartment is widened, Since it is not necessary to increase the thickness of the broken portion together with the thickness, problems such as a decrease in appearance quality due to the gap and an increase in weight and cost due to an increase in the thickness of the general door portion do not occur. In addition, since it is not necessary to increase the thickness of the broken portion, it is possible to smoothly deploy the airbag.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a peripheral structure of a terminal portion of an airbag door according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a terminal portion of the airbag door.

FIG. 3 is a perspective view of an instrument panel.

FIG. 4 is a sectional view showing a conventional airbag door structure.

FIG. 5 is an enlarged sectional view of a terminal portion of a conventional airbag door.

FIG. 6 is a cross-sectional view showing another conventional airbag door structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Instrument panel 2 ... Airbag 4 ... Case 5 ... Door wall 7 ... Breaking part 8 ... Dropping part 8a ... Side face of dropping part 8b ... Shelf surface of dropping part 10 ... Air Bag door 12 Terminal part 14 Peripheral side surface of terminal part 16 Protrusion 20 Slowly changing thin part

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Motoaki Naruse 1-17-18 Edobori, Nishi-ku, Osaka-shi, Osaka Toyo Tire & Rubber Co., Ltd. F-term (reference) 3D054 AA03 AA14 BB09 BB10 BB16 BB23 BB24 DD13 FF20

Claims (2)

[Claims] An airbag device is closed by opening an opening provided in a vehicle interior body for storing the airbag device at a rear side, and is opened and opened by an inflation pressure of an airbag of the airbag device. A door for inflating an airbag into a vehicle interior, comprising: a door wall protruding from a rear surface of the door and attached to a side surface of a case for storing the airbag; and a door wall provided inside the door wall, An airbag door having a thin-walled break portion that breaks due to inflation pressure, wherein an opening edge of the vehicle interior body is dropped to the rear side, and a terminal portion of a door peripheral edge is arranged in the drop portion; The terminal portion is provided with a ridge protruding from the rear surface of the door at a position on the inner peripheral side by a predetermined dimension from the peripheral side surface and facing the shelf surface of the drop portion, whereby the terminal portion has a substantially T-shaped cross section. Is doing The air bag door, wherein the door. 2. A gradually changing thin portion provided on the inner peripheral side of the ridge, the thickness being gradually reduced toward the outer peripheral side with respect to the thickness near the door wall. 2. The airbag door according to 1.