JP2003170800A - Airbag device for protecting knee - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an airbag device for protecting knees, capable of projecting an airbag from a case opening even if an inflator is stored by arranging a gas discharge opening on one side of the case in the vehicle cross direction. <P>SOLUTION: This airbag device S for protecting knees, stores an airbag 40 and an inflator 34 in a case 13. The inflator 34, which is stored in the airbag 40, comprises a body 35 having the gas discharge opening 35c on an end part side thereof and a diffuser 36. The diffuser 36 comprises a cover part 37e which covers the gas discharge opening and gas flow openings 37a, 37b, 37c which guide inflating gas G from the gas discharge opening. In the gas flow openings, on the speed in such a direction that the inflating gas G in the airbag in the vicinity of a case opening 17a travels to the rear side of the vehicle, a central portion 50 thereof in the right and left direction is enlarged and both of right and left portions 51, 52 are opened so as to be mutually almost equal. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a knee-protecting airbag device in which an airbag that inflates by inflating an inflating gas can protect the knees of an occupant such as a driver or a passenger in a passenger seat.

[0002]

2. Description of the Related Art Conventionally, as a device for protecting the knees of an occupant such as a driver, as disclosed in Japanese Patent Laid-Open No. 10-315894, the device is deployed in front of the knees of a seated occupant. The airbag includes an inflatable folded airbag, an inflator that supplies inflation gas to the airbag, and a case that houses and holds the folded airbag and the inflator. Further, the inflator is a cylindrical cylinder type housed in an airbag, and its axial direction is arranged in the left-right direction of the vehicle.

However, in the case of using a hybrid type in which the gas discharge port for discharging the inflation gas is arranged at the end portion in the axial direction as the inflator, the inflator housed in the airbag is used. Means that the gas discharge port is arranged on one edge side in the left-right direction of the case, and the expansion gas discharged from the gas discharge port is
Concentrated on one edge side in the left-right direction of the case, it flows out into the airbag, and as a result, the airbag causes a situation in which it protrudes from one edge side in the vehicle left-right direction in the case opening, and quickly protrudes from the case opening. However, there was a problem in smoothly deploying and inflating the airbag.

The present invention is to solve the above-mentioned problems.
Provided is a knee protection airbag device capable of smoothly projecting an airbag from an opening of a case even if an inflator is housed in the case by arranging a gas discharge port on one side of a case in a vehicle left-right direction. The purpose is to do.

[0005]

A knee protection airbag device according to the present invention comprises a folded airbag and an inflator for supplying inflation gas to the airbag in front of a knee of a seated occupant. A case is provided, which is capable of accommodating and holding and projecting the airbag from the opening to the vehicle rear side when expanded and inflated, and the inflator is arranged so that the axial direction is along the left-right direction of the vehicle. A substantially columnar main body having a gas discharge port capable of discharging an expansion gas on one end side of the main body, and a diffuser for covering the main body and guiding the expansion gas from the main body, A knee protection airbag device having a configuration in which the gas discharge port is disposed on one edge side in the vehicle left-right direction of the case, and is housed in the airbag and housed and held in the case. The diffuser includes a cover portion that covers the periphery of the gas discharge port, and a gas outlet that causes the inflation gas from the gas outlet to flow into the airbag. Regarding the speed of the inflation gas in the airbag in the vicinity of the opening in the direction toward the vehicle rear side, the central portion in the vehicle left-right direction is enlarged so that the portions on the left and right sides of the central portion are mutually It is characterized in that the openings are substantially equal and smaller than the central portion.

Further, the diffuser of the inflator has a holding cylinder portion having the cover portion and the gas outflow port for accommodating and holding the main body therein, and a holding cylinder portion protruding from the holding cylinder portion into the case. Fastening means that can be fastened,
It is preferable that the fixing means is configured to be inserted into the airbag when being fastened to the case, and the main body together with the airbag is attached to the case.

In this case, it is preferable that the cover portion is configured to cover the periphery of the gas discharge port and the end face side of the main body on the gas discharge port side.

Further, in order to suppress the expansion gas flowing out from the gas outlet to the fixing means side, the fixing means is provided on the opposite side of the gas outlet in the circumferential direction of the holding cylinder portion. It is desirable to arrange it in a position.

[0009]

In the knee protection airbag device according to the present invention, the inflation gas is discharged from the gas discharge port of the inflator body when the inflator is activated, and
The gas flows out into the airbag through the diffuser gas outlet of the inflator, and the airbag is expanded and inflated.

At this time, with respect to the speed of the gas outlet in the direction toward the vehicle rear side of the inflation gas in the airbag near the opening of the case, the central portion in the vehicle left-right direction is enlarged so that the left and right sides of the central portion are increased. Openings are made so that the parts on both sides are substantially equal to each other and smaller than the central part. Therefore, the inflation gas flowing out of the gas outlet into the airbag quickly flows to the rear side of the vehicle at the center of the vehicle in the left-right direction. The airbag can be pushed out of the case quickly and smoothly by pushing it strongly to the side. Further, the inflating gas flowing out of the gas outlet into the airbag has a speed toward the vehicle rear side smaller than that of the central portion even in the left and right side portions of the vehicle. Since it is flowing to the vehicle, the protrusion from the case toward the vehicle rear side in the folded portion of the airbag is suppressed from being biased in the vehicle left-right direction.
Can be promoted.

Even if the folded portion of the airbag is pushed out of the case, the inflation gas flowing out into the airbag has a velocity toward the vehicle rear side in the vicinity of the case opening in the center along the left-right direction of the vehicle. Since the left and right portions are made uniform with respect to the portion, the deployment and inflation of the airbag can be promoted in a well-balanced manner in the left-right direction of the vehicle.

Therefore, in the knee protecting airbag device according to the present invention, even if the gas discharge port is disposed on one edge side of the case in the vehicle left-right direction and the inflator is housed in the case, the airbag can be stored in the case. The airbag can be smoothly projected from the opening, and further, the airbag can be deployed and inflated in a well-balanced manner in the left-right direction of the vehicle.

In the case of the second aspect of the invention, the inflator itself holding the main body in the holding cylinder and the airbag can be attached and fixed to the case by using the fixing means of the diffuser. Therefore, the number of parts of the member for attaching the inflator and the airbag to the case can be reduced, and the number of assembly steps and cost of the airbag device can be reduced.

Further, in the case of the third aspect, the expansion gas discharged from the gas discharge port provided on the end portion side of the main body is discharged by the cover portion of the diffuser into the holding cylinder portion. It does not flow from the end face on the outlet side so as to directly hit the airbag, and damage to the region of the airbag near the gas discharge port due to the inflation gas can be prevented.

Further, in the case of the construction as set forth in claim 4, it is difficult for the inflation gas to flow to the fixing means side of the diffuser, that is, to the side where the airbag is attached to the case.
Expansion gas is difficult to flow. Therefore, a large amount of inflation gas does not flow to a portion of the airbag that is not provided to be inflated by the freezing means being restricted by the fixing means. It is possible to prevent damage to the attachment site side.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

The knee protection airbag device S of the embodiment is
As shown in FIGS. 1 and 5, it is arranged below the steering column 3 on the vehicle front side of the driver MD so that the knees K of the driver MD as the occupant M can be protected.

As shown in FIG. 1, the steering column 3 is covered with a column cover 7 and is connected to the steering wheel 1, and a main shaft 4 and a main shaft 4 are provided.
And a column tube 5 that covers the periphery of the
Between the main shaft 4 and the column tube 5, a tilt mechanism (not shown) capable of adjusting the angle of the ring surface of the steering wheel 1 and a telescopic device (not shown) capable of moving the steering wheel 1 in the axial direction of the shaft 4 to stop the steering wheel 1 are provided. Mechanisms and the like are provided.

The column cover 7 is made of a synthetic resin having a substantially rectangular tube shape and is arranged along the axial direction of the steering column 3 so as to cover the steering column 3 below the steering wheel 1. The column cover 7 is arranged so as to project obliquely upward and rearward from an instrument panel (hereinafter referred to as an instrument panel) 9.

The knee protection airbag device S includes a folded airbag 40, an inflator 34 for supplying inflation gas to the airbag 40, and a folded airbag 40.
The air bag cover 26 and the case 13 that cover the vehicle body 13 and the case 13 are provided below the column cover 7 on the vehicle body side. In the airbag device S of the embodiment, the airbag 40, the inflator 34, and the airbag cover 26 are assembled to the case 13 to form an integrally assembled airbag assembly SA, The airbag assembly SA is attached to the vehicle, and the airbag apparatus S is mounted on the vehicle.

The airbag 40 is made of a flexible woven fabric such as polyester or polyamide, and is shown in FIGS.
As shown in FIG. 5, the shape at the time of completion of expansion and expansion is a substantially rectangular plate shape, and the mounting portion 40b that houses the inflator 34 on the lower end 48 side and the mounting portion 40b are disposed above the mounting portion 40b. Main body 40 for increasing the width dimension
a, and is comprised. The mounting portion 40b is a portion that is housed in the case 13 and is held in the case 13 by using the inflator 34 when the deployment and inflation of the airbag 40 is completed. In addition, the airbag 40
Is composed of two woven fabrics, each of which is a substantially rectangular shape, the passenger side wall portion 41 on the driver MD side and the vehicle body side wall portion 42 on the column cover 7 side, and the peripheral edges of the wall portions 41, 42 are sewn together. Has been formed.

The mounting portion 40b on the lower side of the vehicle body side wall portion 42 is formed with two holes 42a, 42a and one hole 42b (see FIG. 3). Two holes 42
Reference character a denotes a through hole 42a that is provided in parallel in the left-right direction of the vehicle and has a circular opening so that a bolt 38, which will be described later, of the inflator 34 can be inserted through the hole 42b. Placed, inflator 3
4 is a through hole 42b that is opened in a circular shape and allows a general portion 35a of a main body 35, which will be described later, to be inserted therethrough. Then, the airbag 40 is inserted into the inflator 3 through the insertion holes 42a and 42a.
The bolt 38d of No. 4 is projected, and the general portion 35a of the inflator 34 is projected from the insertion hole 42b.
Using the inflator 34 stored in the case 1,
It is attached to 3.

The inflator 34 accommodated in the mounting portion 40b of the airbag 40 has a gas discharge port 35c, which will be described later, disposed on the left end portion 45 side of the airbag 40.

Further, in the air bag 40, band-shaped tethers 43, 43 are arranged in two steps in the vertical direction. These tethers 43 are used for the airbag 4 when inflated.
The thickness of 0 is made substantially uniform over the entire area, and the airbag 4 is provided between the knee K of the driver MD and the lower surface 7a of the column cover 7.
It is a thickness control means for allowing 0 to smoothly enter, and is arranged by connecting the passenger side wall portion 41 and the vehicle body side wall portion 42. These tethers 43 have left and right ends 43a and 43b.
Are arranged apart from the left and right end portions 45 and 46 of the airbag 40.

In the airbag 40 of the embodiment,
As shown in FIG. 1, the main body portion 40 a that is folded and stored at the time of expansion and expansion is the storage main body portion 1 of the case 13 to be described later.
7 from the opening 17a to the rear side of the vehicle,
A general portion 2 of the peripheral airbag cover 26, which will be described later.
It is possible to cover from the rear surface of the vehicle 7 to at least the vicinity of the upper end 7b on the lower surface 7a side of the column cover, and to cover the front sides of the left and right knees K of the driver MD.

The airbag 40 of the embodiment has a bilaterally symmetrical shape except for the insertion hole 42b, and a folding shape described later is also bilaterally symmetrical.

As shown in FIGS. 1 to 5, the case 13 is made of sheet metal and is provided with a flat plate-shaped portion 14, a storage main body portion 17 for storing the folded airbag 40 and the inflator 34. It is configured.

The storage body 17 has a bottomed box shape having an opening 17a facing the rear side of the vehicle. Opening 17a
Has a rectangular opening that extends along the left-right direction of the vehicle. And in the case of the embodiment, the storage main body 17
Is a substantially rectangular parallelepiped box shape having a substantially rectangular bottom wall portion 22 and a substantially square tubular peripheral wall portion 18. The peripheral wall portion 18 surrounding the opening 17a has a lateral wall portion in the vicinity of the bottom wall portion 22 in the vehicle left-right direction. An insertion hole 20 for inserting a later-described general portion 35a of the inflator 34 is formed in a portion outside the vehicle O. Further, the bottom wall portion 22 is formed with insertion holes 23, 23 into which bolts 38 of the inflator 34, which will be described later, are inserted.

When the gas discharge port 35c of the inflator 34, which will be described later, is accommodated in the accommodating main body 17, the gas ejecting port 35c approaches the wall 18a of the inner wall I of the peripheral wall 18 away from the insertion hole 20. Will be installed.

Further, on the outer peripheral surface of the peripheral wall portion 18 near the opening 17a, the bottom wall portion 22 is provided so that its tip is separated from the opening 17a.
A plurality of hooks 19 having a substantially J-shaped cross section, which are inverted to the side, are fixed. Three hooks 19 are provided at a portion of the airbag cover 26 that is on the side of a hinge portion 30 (described below) (a portion on the lower surface side of the case peripheral wall portion 18). 5 parts are provided in the area (the area on the upper surface side of the case peripheral wall portion 18).

The plate-shaped portion 14 has an opening 17 in the storage body portion 17.
Left and right knees K of the seated driver MD extending from the peripheral edge of a
It is formed in a substantially rectangular shape so as to widely cover the front side of the vehicle, and mounting pieces 15 for connecting to the vehicle body side are provided at the four corners of the peripheral edge. The vicinity of the upper edge side of the opening 17a in the plate-like portion 14 is recessed downward so that the lower surface 7a side of the column cover 7 projects toward the vehicle rear side, and further, the lower surface 7a is made to correspond to the curved state. And is curved so as to project toward the vehicle rear side. The rib 1 for increasing the rigidity of the plate-shaped portion 14 is provided between the peripheral edge of the opening 17a and the outer peripheral edge of the plate-shaped portion 14.
4a are formed, and these ribs 14a are formed on the rear surface of the vehicle on the general portion 27 of the airbag cover 26, which will be described later.
Is configured to support.

Then, the storage main body 1 in the plate-shaped portion 14
A plurality of through holes 14b that are opened in a substantially rectangular shape are formed on the periphery of the opening 17a of No. 7 so as to penetrate the front and back. These through holes 14b are provided in the airbag cover 26.
The mounting pieces 28 to be locked to the hooks 19 are arranged so that they can be inserted therethrough.

Further, the storage main body portion 17 in the plate-shaped portion 14
A plurality of mounting holes 14c are formed so as to penetrate the front and back sides on both the left and right sides away from. These mounting holes 14
The portion c is a portion where the airbag cover 26 is attached to the case 13 by using thermal caulking. That is, the airbag cover 26 is configured such that the mounting leg portions 27a, which will be described later, of the airbag cover 26 are inserted into the respective mounting holes 14c, so that the mounting leg portions 2a and 2b are attached.
The tip of 7a is melted and expanded in diameter, and the solidified tip is attached to the case 13 together with the hook 19 so as not to come off from the attachment hole 14c.

Further, each mounting piece portion 15 of the case 13 is formed with a connecting hole (not shown) for fixing the bolt 24 (see FIG. 5) to the vehicle body side. Each mounting piece 15 is bolted to a predetermined bracket fixed to the instrument panel reinforcement, center brace, front body pillar, etc. on the body side by bolts 24.
These brackets are configured to be plastically deformable and capable of absorbing impact force.

In the embodiment, the case 13 provided with the plate-like portion 14 and the storage main body 17 is press-formed to be integrally formed. However, the sheet metal is appropriately welded, The case 13 may be formed.

The airbag cover 26 is made of a thermoplastic elastomer such as polyolefin, and is shown in FIGS.
As shown in FIG. 5, the outer shape of the case 13 is larger than the outer shape of the case 13 so as to cover the vehicle rear side of the case 13.

The airbag cover 26 is arranged on the lower panel 9b side of the peripheral edge of the column cover 7 in the instrument panel 9 consisting of the upper panel 9a and the lower panel 9b, and covers the lower peripheral edge of the column cover 7 protruding from the instrument panel 9. Becomes Therefore, the airbag cover 26
Is recessed downward so that the column cover 7 projects rearward when viewed from the vehicle rear side, and the upper edge side below the recess corresponds to the curved surface on the column cover lower surface 7a side. It is configured to be raised so as to be curved toward the vehicle rear side.

The airbag cover 26 comprises a door portion 31 for covering the opening 17a of the storage body portion 17 and a general portion 27 for covering the vehicle rear side of the plate portion 14.

The door portion 31 is formed in a substantially rectangular plate shape slightly larger than the opening 17a, and at the outer edge of the inverted U-shaped portion, the general portion 27 is formed so that the door portion 31 opens downward.
A thin portion 29 to be fractured is formed so as to be connected to. The breakable portion 29 is formed by providing a continuous or intermittent groove on the front surface of the vehicle so that the door portion 31 is easily broken when pushed by the inflating airbag 40. .

On the lower edge side of the door portion 31, there is formed a hinge portion 30 which serves as a center of rotation of the door portion 31 when the scheduled breaking portion 29 is broken and the door portion 31 is opened. The hinge portion 30 is an integral hinge and has a wall thickness within a range that does not break and is thinner than the general portion 27 and the door portion 31.

The storage main body 1 in the general portion 27
In the vicinity of the periphery of the opening 17a of the plate 7,
Mounting pieces 28 penetrating each through hole 14b in FIG.
Is projected on the front side of the vehicle. Each attachment piece 28 has a substantially rectangular plate shape. Each mounting piece 28 is formed with a locking hole 28a that is opened in a rectangular shape for locking the periphery of the mounting piece 28 to the hook 19.

At a predetermined position of the general portion 27, a plurality of mounting leg portions 27a are formed around the periphery of each mounting hole 14c in the plate-shaped portion 14 of the case 13 to be heat-crimped and locked. Each mounting leg portion 27a has a round bar shape capable of penetrating the mounting hole 14c in the state before thermal caulking, and the tip side is crushed after thermal caulking as shown in FIG.

As shown in FIGS. 2 to 4, the inflator 34 is of a cylinder type in which the axial direction is arranged along the left-right direction of the vehicle, and includes a substantially columnar main body 35 and a sheet metal diffuser 36. Is configured.

The main body 35 is of a hybrid type in which an actuation signal is input to burn a predetermined medicine and discharge an inflation gas.
And a small diameter portion 35b having a small diameter protruding from the end surface of the general portion 35a which is the vehicle inside I when the vehicle is mounted on the vehicle, and a plurality of gas discharge ports 35c are arranged on the outer peripheral surface of the small diameter portion 35b. ing. Then, the connector 65 to which the lead wire 66 for inputting the operation signal is connected is connected to the end surface (the end surface on the vehicle outer side O when the vehicle is mounted) of the general portion 35a, which is separated from the small diameter portion 35b.

The diffuser 36 includes a holding cylinder portion 37 made of a substantially cylindrical sheet metal capable of covering the main body 35, and a holding cylinder portion 37.
A plurality of bolts (two in the embodiment) as fixing means protruding from the front side of the vehicle to the vehicle front side. The holding cylinder portion 37 is provided with gas outlets 37a, 37 described later.
Except b * 37c and the insertion hole 37d, it comprises the cover part 37e which covers the peripheral surface side and the end surface side in the periphery of the main body 35.

The gas outlets 37a, 37b, 37c are arranged to guide the inflation gas discharged from the gas discharge port 35c in the small diameter portion 35b of the main body 35 toward the rear side of the vehicle. Is. The gas outlet 37a is opened in a horizontally long rectangular shape, and the main body 3 is provided on the surface of the holding cylinder portion 37 in the vehicle mounted state on the vehicle rear side.
Gas discharge port 3 that is on the inside I of the vehicle from near the center in the axial direction of 5
It is arranged on the 5c side and at a position displaced from the small diameter portion 35b toward the vehicle outer side O so as not to overlap the small diameter portion 35b and the holding cylinder portion 37 in the direction orthogonal to the axis. The gas outlets 37b and 37c each have a substantially square shape with an opening area smaller than that of the gas outlet 37a, and on the surface on the vehicle rear side of the holding cylinder portion 37 mounted in the vehicle,
The main body 35 is juxtaposed in the lateral direction of the vehicle at a position outside the vehicle O near the center in the axial direction.

The opening area and the arrangement position of the gas outlet 37a are the same as those of the airbag 4 near the opening 17a of the case 13.
Regarding the speed of the expansion gas G in the direction toward the vehicle rear side within 0, the central portion 50 in the vehicle left-right direction is enlarged so that the portions 51 and 52 on the left and right sides of the central portion 50 are substantially equal to each other, and , Is set to be smaller than the central portion 50 (see FIG. 9). Gas outlet 37b / 37c
Is an auxiliary of the gas outlet 37a, and with respect to the speed of the expansion gas G in the direction toward the vehicle rear side,
The left and right portions 51 and 52 of the central portion 50 are arranged so as to be substantially equal to each other and smaller than the central portion 50.

The insertion hole 37d is on the outer side O of the holding tubular portion 37.
Is disposed on the end face side of the main body 35 and is opened so that the general portion 35a of the main body 35 can be inserted therethrough.

The cover portion 37e is a cylindrical shield cylindrical portion 37f which covers the periphery of the gas discharge port 35c of the small diameter portion 35b, that is, the axial direction of the main body 35 in the small diameter portion 35b.
And the end of the holding tubular portion 37 on the inner side I of the vehicle is closed, and the small diameter portion 3
5 and a shield end surface portion 37g that covers the end portion side of the main body 35 in the axial direction. Also, the cover portion 3
Reference numeral 7e denotes a half-cylindrical shield half-split portion 37h on the front side of the vehicle at the periphery of the gas outlets 37a, 37b, 37c.
Is provided. The portion of the cover portion 37e between the gas outlets 37a, 37b, 37c on the vehicle rear side is the remaining portion shielding portion 37i.

Further, the cover portion 37e of the holding cylinder portion 37 is provided with a plurality of holding portions 37j for holding the main body 35.
It is arranged. Each of the holding portions 37j is notched on both sides in the axial direction of the holding cylinder portion 37, and is plastically deformed so as to be curved inside the holding cylinder portion 37. The main body 35 is fixed to the holding cylinder portion 37 by inserting the insertion hole 37d.
Therefore, the main body 35 can be fixed to the holding tubular portion 37 by inserting the main body 35 with the small-diameter portion 35b at the top and further pressing the sandwiching portions 37j toward the outer peripheral surface side of the general portion 35a.

In the inflator 34, when the airbag operating circuit mounted on the vehicle detects a frontal collision of the vehicle, the inflator 34 is connected to the airbag device (not shown) mounted on the steering wheel 1 via the lead wire 66. ,
The operation signal will be input.

The assembly of the airbag apparatus S will be described. First, the ridges 41 and 43 of the occupant side wall portion 41 and the vehicle body side wall portion 42 and the tethers 43, 43 are sewn together to form the airbag 40.
When manufacturing the inflator 3 in which the main body 35 is housed and held in advance in the holding cylinder portion 37 of the diffuser 36 from the unsewn portion of the peripheral edges of the wall portions 41 and 42, is left.
4, the bolts 38 are projected from the insertion holes 42a, and the end of the main body 35 on the base portion side is projected from the insertion holes 42b. Then, the unsewn portion of the airbag 40 is sewn.

Next, the airbag 40 is folded. In the folding process of the airbag 40, first, as shown in FIGS. 8A and 8B, the occupant side wall portion 41 and the vehicle body side wall portion 42 are overlapped and flatly developed, and then the width dimension in the left-right direction is narrowed. The left and right ends 45 and 46 sides to the airbag 4
Put in 0. At this time, both ends 43a of each tether 43
・ 43b interferes with a part of the ends 45 and 46,
Portion 4 that does not interfere with the ends 43a and 43b of each tether 43
5a and 46a are put into the airbag 40 as close as possible to the center of the airbag 40 in the left-right direction, and the width dimension in the left-right direction of the airbag 40 after being inserted is determined by the opening 17a of the case 13. Make it compact so as to correspond to the width dimension in the left-right direction at.

Then, as shown in B and C of FIG. 8, the upper end 47 side of the airbag 40 is folded so as to approach the lower end side 48. In the case of the embodiment, if the upper end 47 side is roll-folded on the vehicle body side wall portion 42 side, the folding work of the airbag 40 can be completed.

After the airbag 40 is folded, the airbag 40 is wrapped by a breakable wrapping film (not shown) for preventing collapse. The bolt 38 of the inflator 34 and the end of the general portion 35a of the main body 35 protruding from the mounting holes 42a and 42b are projected from the wrapping film.

Next, each bolt 3 of the inflator 34
8 is projected from the insertion hole 23, and the end of the general portion 35a of the main body 35 is projected from the insertion hole 20,
The inflator 34 having the mounting portion 40b as an exterior is housed in the housing body 17 of the case 13, the folded airbag 68 is housed in the housing body 17, and the nuts 64 are fastened to the bolts 38. Three
4 and the airbag 40 can be housed in the case 13 and attached to the case 13.

Then, the airbag cover 2 is attached to the case 13.
Attach 6. For this attachment, first, from the vehicle rear side of the case 13, the corresponding attachment piece 28 is inserted into each through hole 14b, and the corresponding round bar-shaped attachment leg portion 27a is inserted into each attachment hole 14c. Insert it. At this time, each attachment piece 28 interferes with the hook 19 and elastically deforms away from the storage body 17, and then restores.
The hook 19 is inserted into the locking hole 28a,
The peripheral edge of “a” is locked by the hook 19.

Next, the tips of the mounting legs 27a protruding from the mounting holes 14c are caulked by heat to lock the mounting legs 27a to the peripheral edge of the mounting hole 14c on the vehicle front side surface of the plate portion 14. Then, attach the airbag cover 26 to the case 13.
Can be attached to the airbag assembly SA to form the airbag assembly SA.

In such an airbag assembly SA, if each mounting piece portion 15 of the plate-like portion 14 is bolted to a predetermined bracket on the body side and connected, a knee protecting airbag for a vehicle is provided. The device S can be mounted.

Before mounting the airbag apparatus S on the vehicle, a lead wire 66 extending from a predetermined airbag operating circuit is provided.
The connector 65 in which is connected to the general portion 35a of the inflator 34 is connected in advance.

Then, the upper panel 9a and the lower panel 9b of the instrument panel 9, and the under cover 11 (see FIG.
・ See 2) will be installed in the vehicle.

After the airbag apparatus S is mounted on the vehicle, if an actuation signal is input to the main body 35 of the inflator 34 via the lead wire 66, the inflation gas is discharged from the gas discharge port 35c and the airbag 40 is discharged. Expands and ruptures the wrapping film (not shown) and pushes the door portion 31 of the airbag cover 26 to rupture the intended rupture portion 29, and open the door portion 31 downward with the hinge portion 30 as the center of rotation. As a result, the airbag 40 is, as shown by the two-dot chain line in FIGS. 1 and 2, from the opening 17a of the storage body 17,
Through the opening 32 of the airbag cover 26 formed by opening the door portion 31, the door portion 31 projects toward the vehicle rear side, and further expands and inflates upwardly along the column cover lower surface 7a.

In the knee protection airbag apparatus S of the embodiment, when the inflator 34 is operated, the inflation gas G is discharged from the gas discharge port 35c of the inflator body 35 as shown in FIG. Inflator 3
Gas outlet 37a.3 of the diffuser 36 in FIG.
After passing through 7b and 37c, the air flows into the airbag 40, and the airbag 40 expands and inflates.

At this time, the gas outlets 37a, 37b, 37
c is the velocity of the inflation gas G in the airbag 40 in the vicinity of the opening 17a of the case 13 in the direction toward the vehicle rear side, and the central portion 50 in the vehicle left-right direction is increased,
The left and right portions 51 and 52 of the central portion 50 are opened so that they are substantially equal to each other and smaller than the central portion 50. Therefore, the gas outlets 37a, 37b,
Inflating gas G flowing into the airbag 40 from 37c
At the central portion 50 in the left-right direction of the vehicle, the air flows quickly to the rear side of the vehicle. Therefore, the central portion 40c of the airbag 40 housed in the storage body 17 of the case 13 is strongly pushed to the rear side of the vehicle to quickly. And the air bag 40 smoothly
Can be pushed out of the housing body 17 of the case 13. Further, the inflating gas G flowing out from the gas outlets 37a, 37b, 37c into the airbag 40 has a velocity toward the vehicle rear side smaller than that of the central portion 50 even in the both lateral portions 51, 52 of the vehicle. However, since the air flows to the rear side of the vehicle, the air bag 4
The protrusion from the case 13 toward the vehicle rear side at the folding portion (main body portion 40a) of 0 can be promoted while suppressing the deviation in the vehicle left-right direction.

The folded portion 4 of the airbag 40
Even if 0a is pushed out from the case 13, the airbag 40
The expansion gas G flowing into the vehicle has a velocity toward the vehicle rear side that is equalized in the left-right direction around the central portion 50 along the vehicle left-right direction near the case opening 17a. It is possible to promote the expansion and inflation of the main body portion 40a of the airbag 40 in a well-balanced manner.

Therefore, in the knee protection airbag apparatus S of the embodiment, the inflator 34 is housed in the case 13 so that the gas discharge port 35c approaches the one edge 18a side in the vehicle left-right direction in the case 13. In addition, the airbag 40 can be smoothly projected from the opening 17a of the case 13, and the deployment and inflation of the airbag body 40a can be promoted in a well-balanced manner in the left-right direction of the vehicle.

In particular, in the case of the embodiment, the airbag 4
Since the shape of 0 and the folding are also symmetrical, the airbag 40 can be deployed and inflated evenly in the left and right to widely protect the knees K (KL and KR) of the driver MD.

Further, in the embodiment, the inflator 34 is used.
Of the inflator 34 has a cover portion 37e and gas outlets 37a, 37b, 37c.
A holding cylinder portion 37 for accommodating and holding the main body 35 of
And a bolt 38 as a fixing means that projects from the holding cylinder portion 37 and can be fastened to the bottom wall portion 22 of the case 13. Then, when the bolt 38 is fastened to the case 13, the bolt 38 is inserted into the insertion holes 42 a, 42 of the airbag 40.
It is configured such that the main body 35 is attached to the storage main body portion 17 of the case 13 together with the airbag 40 by being inserted into the a.

That is, in the embodiment, the inflator 34 itself holding the main body 35 in the holding tubular portion 37 and the airbag 40 are attached and fixed to the case 13 by using the bolt 38 as the fixing means of the diffuser 36. Since the inflator 34 and the airbag 40 can be
It is possible to reduce the number of parts of the attachment member to the case 13 and the assembly man-hours and costs of the airbag device S can be reduced.

Further, in the embodiment, the diffuser 36
The cover portion 37e of the holding cylinder portion 37 at 37.sub.3 covers the shield cylindrical portion 37f that covers the periphery of the gas discharge port 35c and the shield end face portion 37g that covers the end face of the main body 35 on the gas discharge port 35c side.
Is equipped with.

Therefore, the expansion gas G discharged from the gas discharge port 35c provided on the end side of the inside 35 of the vehicle body I of the diffuser 36 covers the shield cylindrical portion 37f and the shield end surface portion 37g of the cover portion 37e of the diffuser 36. As a result, the flow does not flow from the end surface side of the inner side I of the holding tubular portion 37 so as to directly hit the airbag 40, and damage to the airbag mounting portion 40b in the vicinity of the gas discharge port 35c due to the inflation gas G is prevented. can do. In particular, in the case of the embodiment, the seam portion 40d (see FIG. 6) of the passenger side wall portion 41 and the vehicle body side wall portion 42 in the mounting portion 40b is arranged near the gas discharge port 35c in the vehicle mounted state. Since the inflation gas G does not directly contact the sutured portion 40d, the sutured portion 40d can be protected.

Further, since the inflation gas G does not flow out from the end surface side of the holding cylinder portion 37 on the vehicle interior side I, the gas discharge port 3
All the expansion gas G from 5c is supplied to the gas outlet 37a.
After passing through 37b and 37c, it becomes possible to flow out into the airbag 40, and the gas outlets 37a, 37b and 37c.
With respect to the speed of the expansion gas G that travels toward the vehicle rear side via the, the speed distribution along the vehicle left-right direction using the gas outlets 37a, 37b, and 37c can be easily set.

Incidentally, in the case of the embodiment, the shielding end face portion 37g of the cover portion 37e completely covers the entire end face of the holding cylinder portion 37 on the gas discharge port 35c side. If the above can be ensured, the entire end surface of the holding cylinder portion 37 on the gas discharge port 35c side may not be completely covered but may be partially opened.

Furthermore, in the embodiment, the gas outlet 3
The bolt 38 serving as a fixing means is provided with gas outlets 37a and 37b in the circumferential direction of the holding cylinder portion 37 so as to suppress the expansion gas G flowing out from 5c toward the bolt 38 side.
Since it is disposed on the vehicle front side, which is the opposite side of 37c, the inflation gas G does not easily flow to the vehicle front side, which is the bolt 38 side of the diffuser 36, that is, to the case 13 of the airbag 40. It is difficult for the inflation gas G to flow around the periphery of the insertion hole 42a, which is the attachment site side. Therefore, the inflation gas G does not flow in a large amount to the peripheral portion of the insertion hole 42a of the airbag 40, which is not provided so as to be inflated, the free inflation of which is regulated by the bolt 38, so that the inflation gas G flows out. At the time, the case 13 in the airbag 40
It is possible to prevent damage to the attachment site side (peripheral edge of the insertion hole 42a) to the.

In the embodiment, the diffuser 36
The three gas outlets 37a, 37b,
The case where 37c is provided is shown. However, regarding the speed of the gas outlet in the direction toward the vehicle rear side of the inflation gas in the airbag in the vicinity of the opening of the case, the central portion in the vehicle left-right direction is enlarged, and the portions on both the left and right sides of the central portion are increased. However, the present invention is not limited to the embodiment as long as the openings are formed so as to be substantially equal to each other and smaller than the central portion. For example, as shown in FIG. 10, a cover portion 37e that covers the periphery of the gas discharge port 35c is provided in the holding cylinder portion 37 of the diffuser 36 so that the small diameter portion 35b and the inflator 34 do not overlap in the axial orthogonal direction. If the holding cylinder portion 37 is displaced in the axial direction and is arranged closer to the gas discharge port 35c than the vicinity of the center of the main body 35 in the axial direction, it is possible to deal with it with one gas outlet 37a.

Of course, with respect to the velocity of the inflation gas in the airbag in the vicinity of the case opening in the direction toward the vehicle rear side, the central portion in the vehicle left-right direction is enlarged so that the portions on the left and right sides of the central portion are mutually Two gas outlets or four or more gas outlets may be provided as long as they are substantially equal and smaller than the central portion.

Further, in the embodiment, in order to protect the knees K of the driver MD, the airbag device S arranged on the vehicle body side of the driver MD in front of the vehicle has been described as an example. The knee protection airbag device may be arranged on the vehicle body side (the instrument panel 9 side) which is the vehicle front side of the occupant seated in the passenger seat so as to protect both knees of the passenger seated passenger.

[Brief description of drawings]

FIG. 1 is a schematic longitudinal cross-sectional view in a vehicle front-rear direction showing a usage state of an airbag device for knee protection according to an embodiment of the present invention.

FIG. 2 is a schematic enlarged vertical sectional view in the vehicle front-rear direction of the knee protection airbag device according to the embodiment.

FIG. 3 is a schematic cross-sectional view of a III-III portion of FIG.

FIG. 4 is a schematic cross-sectional view taken along the line IV-IV in FIG.

FIG. 5 is a schematic front view showing a usage state of the knee protecting airbag device of the embodiment, as viewed from the vehicle rear side.

FIG. 6 is a front view of the airbag used in the embodiment.

7 is a schematic cross-sectional view of a VII-VII part of FIG.

FIG. 8 is a schematic diagram illustrating a folding process of the airbag of the embodiment.

FIG. 9 is a schematic diagram illustrating the flow of expansion gas during operation of the embodiment.

FIG. 10 is a schematic cross-sectional view showing a modified example of the embodiment.

[Explanation of symbols]

13 ... Case, 17 ... Storage main body part, 17a ... Opening, 18a ... One edge (wall part) of the case (vehicle left-right direction), 34 ... Inflator, 35 ... Main body, 35c ... Gas discharge port, 36 ... Diffuser, 37 ... Retaining cylinder part, 37a, 37b, 37c ... Gas outlet, 37e ... Cover part, 37f ... Shielding cylinder part, 37g ... Shielding end face part, 37h ... Shielding half-part, 38 ... (Fixing means) bolt, 40 ... Airbag, G ... Inflation gas, M ... Occupant, MD ... Driver, K ... Knee, S ... Knee protection airbag device.

Claims (4)

[Claims] 1. A folded airbag and an inflator for supplying inflation gas to the airbag are stored and held in front of a seated occupant's knee, and the airbag is expanded and inflated from an opening when the vehicle is inflated. A case that can project to the rear side,
And a substantially columnar main body having an inflator disposed in the axial direction along the left-right direction of the vehicle and having a gas discharge port capable of discharging the inflation gas at one end side in the axial direction, A diffuser that covers the main body and guides the expansion gas from the main body, and the gas discharge port,
A knee protection airbag device configured to be disposed on one edge side in the vehicle left-right direction in the case, housed in the airbag, and housed and held in the case, wherein the diffuser is the gas. A gas outlet that allows the inflation gas from the gas outlet to flow into the airbag, and the gas outlet is located near the opening of the case. Regarding the speed of the inflation gas in the airbag in the direction toward the vehicle rear side, the central portion in the vehicle left-right direction is increased,
An airbag device for knee protection, wherein the left and right sides of the central portion are opened so that they are substantially equal to each other and smaller than the central portion. 2. The holding diffuser of the inflator, which has the cover portion and the gas outlet, holds the main body inside, and a holding cylinder portion that protrudes from the holding cylinder portion to the case. Fastening means that can be fastened, and the fastening means inserts the airbag at the time of fastening to the case, and together with the airbag, the main body,
The knee protection airbag device according to claim 1, wherein the airbag device is attachable to the case. 3. The knee according to claim 2, wherein the cover portion is configured to cover the periphery of the gas discharge port and an end surface side of the main body on the gas discharge port side. Airbag device for protection. 4. The fixing means is provided on the opposite side of the gas outlet in the circumferential direction of the holding cylinder so as to suppress the expansion gas flowing out from the gas outlet toward the fixing means. The knee protection airbag device according to claim 2 or 3, wherein the airbag device is disposed at a position.