# Patent

## Title
Seat-mounted airbag device

## Abstract

A seat-mounted airbag device includes an inflator, an airbag body, and a guide member. The airbag body includes a front-rear chamber and a tip chamber. The front-rear chamber is deployed forward of a seat through a clearance between a window and a head of an occupant from a side portion of a headrest on a window side by gas ejected from the inflator and disposed between the window and the head of the occupant. The tip chamber is deployed inward in a seat width direction from an end portion of the front-rear chamber on a seat front side and disposed forward of a face of the occupant on the seat front side. The guide member protrudes from the side portion prior to deployment of the airbag body and is interposed between the airbag body and the head of the occupant.

## Background
CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to Japanese Patent Application No. 2021-096914 filed on Jun. 9, 2021, incorporated herein by reference in its entirety.
BACKGROUND
1. Technical Field
The present disclosure relates to a seat-mounted airbag device.
2. Description of Related Art
A side airbag device has been known in which the side airbag device includes an airbag body portion that is deployed forward from one side of a seat back and that is disposed on the upper body (including the head) side of an occupant and an airbag protruding portion that is deployed inward in a seat width direction from the airbag body portion and that is disposed forward of the face of the occupant in the event of a frontal collision of a vehicle (see, for example, Japanese Unexamined Patent Application Publication No. 2006-008105 (JP 2006-008105 A)).
SUMMARY
However, when the airbag device is mounted on the side of the seat back facing a window side and the head of the occupant is closer to the window side during a frontal collision of the vehicle, a clearance between the window and the head of the occupant becomes narrow and it becomes difficult for an airbag to be deployed, which may cause delay in deployment of the airbag. Especially in a case of an airbag housed to be folded in a bellows shape of which the deployment speed is high, the airbag may get caught on the head of an occupant during deployment of the airbag. As described above, there is room for improvement in the airbag device in which the airbag is deployed through the clearance between the window and the head of the occupant.
Therefore, the present disclosure provides a seat-mounted airbag device in which the airbag body is smoothly deployed even when the clearance between the window and the head of the occupant is narrow.
The seat-mounted airbag device according to an aspect of the present disclosure includes an inflator that is operated when a vehicle collision is detected or predicted and ejects gas, an airbag body that includes a front-rear chamber that is deployed forward of a seat through a clearance between a window and a head of an occupant from a side portion of a headrest on a window side by the gas ejected from the inflator and disposed between the window and the head of the occupant and a tip chamber that is deployed inward in a seat width direction from an end portion of the front-rear chamber on a seat front side and disposed forward of a face of the occupant on the seat front side, and a guide member that protrudes from the side portion prior to deployment of the airbag body and is interposed between the airbag body and the head of the occupant.
According to the aspect of the present disclosure, when the airbag body is deployed forward of the seat through the clearance between the window and the head of the occupant from the side portion of the headrest on the window side by the gas ejected from the inflator, the guide member interposed between the airbag body and the head of the occupant protrudes from the side portion prior to the deployment of the airbag body. Therefore, even when the airbag body is deployed from the side portion of the headrest on the window side, there is no possibility that the airbag body will get caught on the head of the occupant. Therefore, even when the head of the occupant is closer to the window side and the clearance between the window and head of the occupant is narrow, the airbag body is smoothly deployed.
Further, in the seat-mounted airbag device according to the aspect, the guide member may be composed of a cloth.
According to the aspect, the guide member may be composed of the cloth. Therefore, even when the guide member hits the head of the occupant, the head of the occupant is less likely to be hurt than when the guide member is composed of, for example, a plastic material.
Further, in the seat-mounted airbag device according to the aspect, the guide member may be composed of a front wall of the side portion.
According to the aspect, the guide member may composed of the front wall of the side portion. Therefore, the manufacturing cost of the headrest is reduced as compared with a case where the guide member is provided separately from the side portion.
Further, in the seat-mounted airbag device according to the aspect, the guide member may be composed of a front wall of the side portion and a cloth provided in the front wall.
According to the aspect, the guide member may composed of the front wall of the side portion and the cloth provided in the front wall. Therefore, the manufacturing cost of the headrest is reduced as compared with a case where the guide member is composed of only the cloth.
As described above, according to the present disclosure, even when the clearance between the window and the head of the occupant is narrow, the airbag body can be smoothly deployed.



BRIEF DESCRIPTION OF THE DRAWINGS
Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like signs denote like elements, and wherein:
FIG. 1 is a side view showing a seat-mounted airbag device according to the present embodiment in a deployed state;
FIG. 2 is a plan view showing the seat-mounted airbag device according to the present embodiment in a deployed state;
FIG. 3 is an enlarged plan view showing a state in which a seat-mounted airbag device according to a first embodiment before being deployed is partially broken;
FIG. 4 is an enlarged plan view showing a state in which the seat-mounted airbag device according to the first embodiment in a deploying state is partially broken;
FIG. 5 is a developed view showing an enlarged state of an airbag body, which is in an unfolded state, in the seat-mounted airbag device according to the first embodiment;
FIG. 6 is an enlarged plan view showing a state in which a seat-mounted airbag device according to a second embodiment in a deploying state is partially broken;
FIG. 7 is an enlarged plan view showing a state in which a seat-mounted airbag device according to a third embodiment before being deployed is partially broken; and
FIG. 8 is an enlarged plan view showing a state in which the seat-mounted airbag device according to the third embodiment in a deploying state is partially broken.



DETAILED DESCRIPTION OF EMBODIMENTS
Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the drawings. For convenience of description, the arrow UP, the arrow FR, and the arrow RH appropriately shown in the figures indicate the upward direction of a seat, the forward direction of the seat, and the right direction of the seat, respectively. Thus, when terms indicating directions, i.e., upward and downward, forward and rearward, and right and left are used in the following description without any specification, these mean upward and downward of the vehicle seat, forward and rearward of the vehicle seat, and right and left of the vehicle seat. Further, the right-left direction is synonymous with a seat width direction.
Further, a seat-mounted airbag device (hereinafter, simply referred to as an “airbag device”) 30 according to the present embodiment is provided inside a case portion 20 (to be described below) constituting a headrest 16 of a vehicle seat 10 as a rear seat of a vehicle. Therefore, although the vehicle seat 10 according to the present embodiment is described as a rear seat, the airbag device 30 may be provided in a front seat.
Further, as will be described below, the airbag device 30 is deployed forward through the clearance between the side window 18 as a window and a head Ph of an occupant P (along a side window 18). Therefore, this airbag device 30 is applied to a vehicle that does not include a curtain airbag device, and a front-rear chamber 34 to be described below functions as a curtain airbag.
Further, the “window” in the present embodiment includes a state in which the side window 18 is open as well as a state in which the side window 18 is closed. Further, the “occupant P” in the present embodiment is, for example, an occupant corresponding to an AM 50 dummy doll.
First Embodiment
First, the airbag device 30 according to a first embodiment will be described. As shown in FIGS. 1 and 2, the vehicle seat 10 includes a seat cushion 12 on which the occupant P sits (supports the buttocks and thighs of the occupant P), a seat back 14 that supports the back of the occupant P, and the headrest 16 that supports the head Ph of the occupant P.
The headrest 16 includes a body portion 16A having a block shape that is provided at the center of the upper end portion of the seat back 14 in the seat width direction such that the body portion 16A can move up and down. Specifically, a pair of right and left stays having a columnar shape (not shown) is provided at the center of the lower surface of the body portion 16A in the seat width direction.
Each stay is inserted in each of a pair of right and left headrest supports 26 having a substantially cylindrical shape that is provided at the center of the upper end portion of the seat back 14 in the seat width direction (see FIGS. 3 and 4) so as to move up and down and be able to be fixed at a plurality of predetermined positions. Further, the headrest 16 includes the case portion 20 continuously provided from the rear of the body portion 16A to both the right and left sides.
That is, the case portion 20 is formed in a substantially “U” shape with the front side open in a plan view. The body portion 16A is disposed on the inner side of the case portion 20 with almost no clearance. In the case portion 20, the front end surfaces (outer surface of a front wall 20F) of the right and left side portions 24 extending in a front-rear direction are substantially flush with the front surface of the body portion 16A (see FIGS. 2 and 3).
Further, right and left outer walls 20A (side portions 24) and a rear wall 20B of the case portion 20 are composed of a resin cover member 22 having a substantially “U” shape in a plan view. The upper wall (not shown), the lower wall (not shown), a front wall 20F, and an inner peripheral wall 20C facing the body portion 16A in the case portion 20 are composed of urethane foam 23, and the outer surface of the cover member 22 and the urethane foam 23 is integrally covered with a skin material 21.
A predetermined space portion S (including a housing portion S1 and a locating portion S2 to be described later) is provided inside the case portion 20. An airbag body 32 of the airbag device 30 is housed in the housing portion S1 provided in a side portion 24R of the case portion 20 on the side window 18 side (right side in the figure).
As shown in FIGS. 1 and 2, the airbag device 30 includes the airbag body 32 that is deployed forward from the rear side of the head Ph of the occupant P (specifically right rear side) seated on the vehicle seat 10 when gas is ejected from an inflator 28 (see FIGS. 3 and 4) to be described below.
The airbag body 32 includes the front-rear chamber 34 that is disposed between the side window 18 and the head Ph of the occupant P and a tip chamber 36 that is deployed inward in the seat width direction from the front end portion of the front-rear chamber 34 and is disposed forward of the face of the occupant P. Then, the airbag body 32 includes a tether 38 having a string shape that connects a predetermined position at the upper end portion of the front-rear chamber 34 and a predetermined position at the upper end of the tip chamber 36.
That is, the airbag body 32 is bent in a substantially “V” shape in a plan view to restrain at least a part of the head Ph and the chest of the occupant P. The tether 38 may be provided so as to connect at least the upper end portion of the front-rear chamber 34 and the upper end portion of the tip chamber 36, and provided, for example, so as to further connect a predetermined position at the lower end portion of the front-rear chamber 34 and a predetermined position at the lower end portion of the tip chamber 36.
As shown in FIG. 3, the inflator 28 is disposed in the locating portion S2 that is the rear side of the space portion S provided in the case portion 20. The inflator 28 has a substantially cylindrical shape, and the outer peripheral portion thereof is supported by a reaction force plate (not shown) having a housing shape via a retainer (not shown) such that the axial center portion thereof is disposed along the seat width direction.
The reaction force plate is fixed to, for example, a seat back frame (not shown) via a bracket (not shown), and is configured to be able to receive reaction force transmitted from the airbag body 32 deployed forward via the inflator 28. The reaction force plate and the retainer are also located in the locating portion S2.
The inflator 28 is electrically connected to an airbag electronic control unit (ECU) (not shown) provided in the vehicle, and a detection device (not shown) such as an acceleration sensor provided in the vehicle and the airbag ECU are electrically connected. Therefore, when a collision of the vehicle is detected by the detection device, the inflator 28 is operated via the airbag ECU to instantly eject the gas.
The inflator 28 may not be configured to be operated when a collision of the vehicle is detected, but may be configured to be operated when a collision of the vehicle is predicted by a collision prediction sensor or the like (not shown). Then, a connecting portion 31 (see also FIG. 5) of the airbag body 32 is fitted and connected to the ejection port of the inflator 28.
The airbag body 32 is housed in the housing portion S1 provided in the side portion 24R in a state in which the airbag body 32 is folded in a bellows shape (a plurality of folds that cross each other at a predetermined length) in a plan view. Therefore, as shown in FIG. 4, the airbag body 32 is deployed forward through the clearance between the side window 18 and the head Ph of the occupant P from the side portion 24R (along the side window 18) while the airbag body 32 having a bellows shape is unwound by the gas ejected from the inflator 28.
Further, the front wall 20F constituting the front end surface of the side portion 24R is broken, for example, linearly along the up-down direction when the airbag body 32 is deployed. In some embodiments, a portion to be broken may be a seat width direction outer end portion 20T of the front wall 20F. In some embodiments, in other words, a fragile portion or the like that is easily broken may be provided at the seat width direction outer end portion 20T of the front wall 20F.
When the portion to be broken is the seat width direction outer end portion 20T of the front wall 20F, the front wall 20F is opened with a seat width direction inner end portion 20N as a hinge portion, so that the airbag body 32 to be deployed can be further suppressed from coming into contact with the head Ph of the occupant P.
Further, as shown in FIG. 3, in the housing portion S1 provided in the side portion 24R, a cloth (hereinafter referred to as a “guide cloth”) 42 as a guide member 40 that protrudes from the side portion 24R (housing portion S1) prior to deployment of the airbag body 32 and is interposed between the airbag body 32 and the head Ph of the occupant P is provided.
One end portion of the guide cloth 42 is fixed by sewing or the like to a side wall 32B on the inner side of a base portion 32A of the airbag body 32 in the seat width direction, the base portion remaining in the housing portion S1 even after deployment of the airbag body 32. The other end portion of the guide cloth 42 is disposed along the inner surface of the outer wall 20A of the side portion 24R by passing through a space between the airbag body 32 housed in a bellows shape and the inner surface of the front wall 20F.
Therefore, as shown in FIG. 4, when the gas is ejected from the inflator 28 and the airbag body 32 breaks the front wall 20F and is deployed, the other end portion of the guide cloth 42 is pushed by the airbag body 32 and protrudes from the side portion 24R (housing portion S1), and the guide cloth 42 is interposed between the airbag body 32 and the head Ph of the occupant P.
In some embodiments, the length of the guide cloth 42 along a protruding direction may be a length to the extent that the right side of the face of the occupant P can be covered in a plan view. Further, in some embodiments, the height of the guide cloth 42 (length along the up-down direction) may be a height to the extent that the right side of the face of the occupant P can be covered, and approximately 250 mm to 300 mm, for example.
Further, in some embodiments, the guide cloth 42 may have higher rigidity than the airbag body 32, and a coated cloth in which a material (base cloth) constituting the airbag body 32 is coated with silicon rubber or the like be adopted. However, the guide cloth 42 is not limited to this, and may be composed of, for example, the same material as the airbag body 32.
Further, as shown in FIG. 5, three first non-expanding portions 35 extending in the up-down direction are provided to be sewn at predetermined intervals in the up-down direction. The first non-expanding portions 35 are provided at the substantially central portion of the airbag body 32 in the front-rear direction in a state where the airbag body 32 is not filled with the gas. A second non-expanding portion 37 extending in the front-rear direction is continuously provided to be sewn on the upstream side with respect to the first non-expanding portion 35 in a deployment direction, the first non-expanding portion 35 being located at the substantially central portion in the up-down direction.
The first non-expanding portions 35 and the second non-expanding portion 37 allow the tip chamber 36 to bend inward in the seat width direction with respect to the front-rear chamber 34, and to be deployed inward in the seat width direction. That is, in the airbag body 32, the upstream side with respect to the first non-expanding portions 35 in the deployment direction is the front-rear chamber 34, and the downstream side with respect to the first non-expanding portions 35 in the deployment direction is the tip chamber 36.
Next, the operation of the airbag device 30 according to the first embodiment having the above configuration will be described.
When the detection device detects that a frontal collision has occurred the vehicle, the inflator 28 is operated and instantly ejects gas into the airbag body 32. When the gas is ejected into the airbag body 32, the airbag body 32 is deployed. However, prior to the deployment of the airbag body 32, the guide cloth 42 protrudes from the side portion 24R. That is, the front wall 20F of the side portion 24R is broken by the airbag body 32 to be deployed, and the other end portion of the guide cloth 42 is pushed out from the side portion 24R (housing portion S1).
As a result, the guide cloth 42 is interposed between the airbag body 32 and the head Ph of the occupant P, and the airbag body 32 is deployed forward along the side window 18 on the outer side of the guide cloth 42 in the seat width direction. That is, the airbag body 32 is deployed forward through the clearance between the side window 18 and the guide cloth 42 (head Ph of the occupant P) from the side portion 24R.
Therefore, at the time of deployment, even when the head Ph of the occupant P is closer to the side window 18 side, as shown by solid lines in FIGS. 3 and 4 for example, from the position indicated by long dashed double-short dashed lines, and the clearance between the side window 18 and the guide cloth 42 (head Ph of the occupant P) is narrow, the airbag body 32 is not likely to get caught on the head Ph of the occupant P and can be easily and smoothly deployed along the side window 18.
Then, the head Ph and at least a part of the chest of the occupant P seated on the vehicle seat 10 is restrained by the fully deployed airbag body 32 (front-rear chamber 34 and tip chamber 36). Therefore, it is possible to suppress movement of the head Ph and at least the part of the chest of the occupant P forward due to the inertial force by the airbag body 32 (front-rear chamber 34 and tip chamber 36).
Further, as described above, the guide cloth 42 protrudes prior to the deployment of the airbag body 32 and is interposed between the airbag body 32 and the head Ph of the occupant P. Therefore, when the airbag body 32 is deployed, there is no possibility that the face of the occupant P will be hurt by the airbag body 32. In other words, the guide cloth 42 can protect the face of the occupant P.
Further, since the guide member 40 is composed of the guide cloth 42, the head Ph of the occupant P is less likely to be hurt than when the guide member 40 is composed of, for example, a plastic material even when the guide member 40 (guide cloth 42) hits the head Ph of the occupant P.
Further, when the airbag body 32 is deployed, the front wall 20F is opened with the seat width direction inner end portion 20N as a hinge portion. Therefore, the airbag body 32 to be deployed can be further suppressed from coming into contact with the head Ph of the occupant P by the front wall 20F.
Second Embodiment
Next, the airbag device 30 according to a second embodiment will be described. The same parts as those in the first embodiment are designated by the same reference signs, and detailed description thereof (including common operations) will be omitted as appropriate.
As shown in FIG. 6, the second embodiment differs from the first embodiment only in that the guide cloth 42 is not provided and the guide member 40 is composed of only the front wall 20F. That is, the front wall 20F of which the seat width direction outer end portion 20T is broken due to the deployment of the airbag body 32 is opened with the seat width direction inner end portion 20N as a hinge portion, so that the front wall 20F is interposed between the airbag body 32 to be deployed and the head Ph of the occupant P.
As a result, when the airbag body 32 is deployed forward through the clearance between the side window 18 and the head Ph of the occupant P from the side portion 24R by the gas ejected from the inflator 28, the airbag body 32 is suppressed or prevented from getting caught on the head Ph of the occupant P, and can be easily and smoothly deployed along the side window 18.
Further, when the guide member 40 is composed of only the front wall 20F of the side portion 24R as in the second embodiment, the manufacturing cost of the case portion 20 (headrest 16) can be reduced as compared with a case where the guide member 40 is provided separately from the side portion 24R (for example, the guide member 40 is composed of only the guide cloth 42).
Third Embodiment
Next, the airbag device 30 according to a third embodiment will be described. The same parts as those in the first embodiment and the second embodiment are designated by the same reference signs, and detailed description thereof (including common operations) will be omitted as appropriate.
As shown in FIGS. 7 and 8, the third embodiment is different from the first embodiment and the second embodiment only in that a guide cloth 44 is provided at the seat width direction outer end portion 20T of the front wall 20F. That is, the guide member 40 in the third embodiment is composed of the front wall 20F and the guide cloth 44.
The guide cloth 44 is different from the guide cloth 42 only in that the length of the guide cloth 44 along the protruding direction is shorter than that of the guide cloth 42, and the height thereof (length along the up-down direction) is the same as that of the guide cloth 42. Then, one end portion of the guide cloth 44 is attached to the seat width direction outer end portion 20T of the front wall 20F by sewing or the like, and the other end portion of the guide cloth 44 is disposed along the inner surface of the outer wall 20A of the side portion 24R.
In this state, the other end portion of the guide cloth 44 is disposed at the same position as the other end portion of the guide cloth 42. In other words, the length of the guide cloth 44 along the protruding direction is set such that the other end portion of the guide cloth 44 disposed along the inner surface of the outer wall 20A of the side portion 24R is disposed at the same position as the other end portion of the guide cloth 42.
With the guide member 40 having such a configuration, as shown in FIG. 8, the seat width direction outer end portion 20T of the front wall 20F of the side portion 24R is broken by the airbag body 32 to be deployed, and when the front wall 20F pivots with the seat width direction inner end portion 20N as a hinge portion, the other end portion of the guide cloth 44 is pushed out from the side portion 24R (housing portion S1).
As a result, the front wall 20F and the guide cloth 44 are interposed between the airbag body 32 and the head Ph of the occupant P, and the airbag body 32 is deployed forward along the side window 18 on the outer side of the front wall 20F and the guide cloth 44 in the seat width direction. That is, the airbag body 32 is deployed forward through the clearance between the side window 18, and the front wall 20F and the guide cloth 44 (head Ph of the occupant P) from the side portion 24R.
Therefore, at the time of deployment, even when the head Ph of the occupant P is closer to the side window 18 side, as shown by solid lines in FIGS. 7 and 8 for example, from the position indicated by long dashed double-short dashed lines, and the clearance between the side window 18, and the front wall 20F and the guide cloth 44 (head Ph of the occupant P) is narrow, the airbag body 32 is not likely to get caught on the head Ph of the occupant P and can be easily and smoothly deployed along the side window 18.
Further, when the guide member 40 is composed of the front wall 20F of the side portion 24R and the guide cloth 44 provided in the front wall 20F as in the third embodiment, the manufacturing cost of the case portion 20 (headrest 16) can be reduced as compared with a case where the guide member 40 is composed of only the guide cloth 42.
The seat-mounted airbag device 30 according to the present embodiment has been described above with reference to the drawings, but the seat-mounted airbag device 30 according to the present embodiment is not limited to the illustrated embodiments and its design can be changed as appropriate within the scope of the present disclosure. For example, the reaction force plate that supports the inflator 28 may be fixed via a bracket to the headrest support 26 instead of the seat back frame.
Further, the guide member 40 is not limited to the guide cloth 42 or the front wall 20F, and further a member composed of the front wall 20F and the guide cloth 44. The guide member 40 may have any configuration as long as the guide member 40 protrudes from the side portion 24R prior to the deployment of the airbag body 32 and is interposed between the airbag body 32 and the head Ph of the occupant P.
For example, the guide member 40 may slide along the inner surface of the inner peripheral wall 20C of the case portion 20 and protrude with the deployment of the airbag body 32, and may be composed of a sheet-shaped member that is made of soft resin and is interposed between the airbag body 32 and the head Ph of the occupant P.

## Claims

1. A seat-mounted airbag device comprising:
an inflator that is operated when a vehicle collision is detected or predicted and ejects gas;
an airbag body that includes a front-rear chamber configured to be deployed forward of a seat through a clearance between a window and a head of an occupant from a side portion of a headrest on a window side by the gas ejected from the inflator and configured to be disposed between the window and the head of the occupant, and a tip chamber that is deployed inward in a seat width direction from an end portion of the front-rear chamber on a seat front side and configured to be disposed forward of a face of the occupant on the seat front side, the airbag body bent in a V-shape in a plan view when deployed, and; and
a guide member that protrudes from the side portion prior to deployment of the airbag body and is configured to be interposed between the airbag body and the head of the occupant.

2. The seat-mounted airbag device according to claim 1, wherein the guide member is composed of a cloth.

3. The seat-mounted airbag device according to claim 1, wherein the guide member is composed of a front wall of the side portion.

4. The seat-mounted airbag device according to claim 1, wherein the guide member is composed of a front wall of the side portion and a cloth provided at the front wall.