Airbag device and occupant protection apparatus

Abstract

To improve mountability while ensuring silencing performance, in a configuration in which an inflator is mounted on an upper part of a vehicle seat.SOLUTION: An airbag device 30 comprises: an inflator 60 mounted on an upper part of a vehicle seat 12, and generating gas upon a vehicle collision; an airbag 32 to which the gas from the inflator 60 is supplied, and which is inflated and deployed from the upper part of the vehicle seat 12 toward a seat front side; and a diffuser 62 for distributing the gas to the airbag. The diffuser 62 comprises: a connection part 62A connected to the inflator 60; and a plurality of branch parts 62B branching from the connection part 62A and each connected to the airbag 32. A silencing part for reducing sound pressure of the gas is provided in the connection part 62A and the plurality of branch parts 62B.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an airbag device and an occupant protection device equipped with an airbag device. [Background technology]

[0002] The inflator with silencer disclosed in the following Patent Document 1 has a gas chamber that generates or stores high-pressure gas for inflating an airbag, a first gas hole provided in the wall of the gas chamber for discharging the high-pressure gas, and a silencer connected to the first gas hole for reducing the sound pressure caused by the discharged gas and supplying the gas to the airbag. The silencer has a cylindrical cavity in which the first gas hole opens on one end face and inflates the gas discharged from the first gas hole, and a second gas hole that opens on the other end face of the cavity, has a cross-sectional area larger than that of the first gas hole, and supplies the gas expanded in the cavity to the airbag. The gas discharged from the gas chamber expands in the cylindrical cavity in the silencer and the pressure is reduced, so that the sound pressure caused by the discharged gas is reduced. As a result, even if the inflator with silencer is mounted on a headrest close to the ears of the occupant, it is said that it does not adversely affect the ears of the occupant. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Registered Utility Model No. 3015513 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned prior art, the muffler fixed to the end surface of the cylindrical inflator has a cylindrical cavity with an outer diameter larger than that of the inflator, thereby ensuring muffling performance. This results in a larger overall outer diameter of the muffler-equipped inflator and a longer overall length of the inflator. As a result, it is considered that there are space limitations when mounting the muffler-equipped inflator on the upper part of a vehicle seat.

[0005] In consideration of the above, an object of the present invention is to provide an airbag device that can improve mountability while ensuring soundproofing performance in a configuration in which an inflator is mounted on the upper part of a vehicle seat, and an occupant protection device equipped with the airbag device. [Means for solving the problem]

[0006] The airbag device of the first aspect includes an inflator mounted on an upper portion of a vehicle seat and generating gas in the event of a vehicle collision, an airbag to which the gas is supplied and which inflates and deploys from the upper portion toward the front of the seat, and a diffuser having a connection portion connected to the inflator and a plurality of branch portions branching off from the connection portion and each connected to the airbag, distributing the gas to the airbag and having sound-absorbing portions at least at the plurality of branch portions that reduce the sound pressure of the gas.

[0007] According to the first aspect, in the event of a vehicle collision, gas generated from an inflator mounted on the upper part of the vehicle seat is supplied to the diffuser and distributed to the airbag, and the airbag inflates and deploys from the upper part of the vehicle seat to the front side of the seat. The diffuser has a connection part connected to the inflator and a plurality of branch parts branched from the connection part and connected to the airbag, and the gas is distributed to a plurality of locations of the airbag through the plurality of branch parts. In this diffuser, at least the plurality of branch parts are provided with sound absorbing parts that reduce the sound pressure of the gas, so that sound absorbing performance can be ensured even if the plurality of branch parts are each set to a small diameter. Moreover, the plurality of branch parts set to a small diameter can be arranged to fit the space above the vehicle seat, so that the mountability at the upper part of the vehicle seat can be improved.

[0008] In the airbag device of the second aspect, in the first aspect, the airbag has a front and rear chamber including a pair of left and right front and rear extending portions that pass through both the left and right sides of the head of an occupant seated in the vehicle seat and inflate and deploy toward the front side of the seat, and an airbag body that is supplied with gas through the front and rear chambers and inflates and deploys in front of the occupant, and the multiple branch portions of the diffuser are connected to at least the pair of front and rear extending portions.

[0009] In a second aspect, the airbag has front and rear chambers and an airbag body. The front and rear chambers include a pair of left and right front and rear extending portions that inflate and deploy toward the front side of the seat through the left and right sides of the head of an occupant seated in a vehicle seat. The airbag body is supplied with gas from an inflator through the front and rear chambers and inflates and deploys in front of the occupant. The multiple branching portions of the diffuser are connected to at least the pair of front and rear extending portions of the front and rear chambers. This allows the gas from the inflator to be distributed to each of the pair of front and rear extending portions, respectively, which makes it possible to reduce the mounting space, manufacturing costs, and number of parts compared to a configuration in which gas is supplied from separate inflators to each of the pair of front and rear extending portions, for example.

[0010] In the airbag device of the third aspect, in the second aspect, the front and rear chambers include a connecting portion that connects the front ends of the pair of front and rear extending portions in the left-right direction of the seat, and the airbag main body inflates and deploys toward the occupant on the seat rear side of the connecting portion after the front and rear chambers.

[0011] In a third aspect, the front and rear chambers of the airbag include a connecting portion that connects the front ends of the pair of front and rear extensions in the seat left-right direction, and the airbag body inflates and deploys toward the occupant on the seat rear side of the connecting portion after the front and rear chambers. When the occupant is restrained, the airbag body is compressed in the seat front-rear direction while expanding the front and rear chambers in the seat front-rear direction. This compressive deformation of the airbag body can improve energy absorption performance.

[0012] The airbag device of a fourth aspect is any one of the first to third aspects, in which the sound-absorbing section is a plurality of partitions provided inside the diffuser, and the inside of the diffuser is divided into a plurality of chambers that are connected to each other by the plurality of partitions.

[0013] In the fourth aspect, the inside of the diffuser is divided into a plurality of chambers that communicate with each other by a plurality of partition walls provided inside the diffuser, whereby the diffuser functions as a partition wall type silencer, and the sound pressure of the gas from the inflator can be effectively reduced.

[0014] The airbag device of a fifth aspect is the airbag device of the fourth aspect, wherein the partition wall is inclined toward the downstream side in the flow direction of the gas flowing inside the diffuser.

[0015] In the fifth aspect, since the partition wall provided inside the diffuser is configured as described above, it is possible to suppress the flow of gas flowing inside the diffuser from being obstructed by the partition wall.

[0016] The passenger protection device of a sixth aspect includes a vehicle seat on which a passenger sits, and an airbag device of any one of the first to fifth aspects mounted on an upper portion of the vehicle seat.

[0017] In the sixth aspect, an airbag device is mounted on the upper part of a vehicle seat on which an occupant sits. This airbag device is one of the first to fifth aspects, and therefore has the same effects as any one of the first to fifth aspects. Effect of the Invention

[0018] As described above, according to the present invention, in a configuration in which an inflator is mounted on the upper part of a vehicle seat, it is possible to improve mountability while ensuring sound deadening performance. [Brief description of the drawings]

[0019] [Figure 1] 1 is a perspective view showing a state in which an airbag is inflated and deployed in an occupant protection device according to an embodiment; [Diagram 2] 2 is a side view showing the configuration shown in FIG. 1 as viewed from the left side of the vehicle. [Diagram 3] 2 is a plan view showing the configuration shown in FIG. 1 as viewed from above the vehicle. [Figure 4] 2 is a front view showing the configuration shown in FIG. 1 as viewed from the front of the vehicle. [Diagram 5] 5 is a front view showing the airbag in FIG. 4 in a see-through state. FIG. [Figure 6] FIG. 2 is a development view showing front and rear chambers of the airbag. [Figure 7] FIG. 2 is a development view showing an airbag body provided in the airbag. [Figure 8] FIG. 2 is a front view showing the diffuser and the inflator. [Figure 9] FIG. 4 is a side view showing the diffuser and the inflator. [Figure 10] FIG. 2 is a cross-sectional view showing a diffuser. [Figure 11]FIG. 11 is a cross-sectional view showing a modified example of the diffuser. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] An occupant protection device 10 according to an embodiment of the present invention will be described below with reference to Figs. 1 to 10. In each drawing, some reference numerals may be omitted to make the drawing easier to see. Arrows FR, UP, LH, and RH, which are appropriately indicated in each drawing, respectively indicate the forward direction (traveling direction), upward direction, leftward direction, and rightward direction of the vehicle. In the following description, when the directions of front-rear, left-right, and up-down are simply used, they refer to front-rear in the front-rear direction of the vehicle, left-right in the left-right direction of the vehicle, and up-down in the up-down direction of the vehicle, unless otherwise specified.

[0021] As shown in Figs. 1 to 5, the passenger protection device 10 is composed of a vehicle seat 12 and an airbag device 30. The vehicle seat 12 is a front seat or a rear seat of a vehicle (automobile). The vehicle seat 12 has a seat cushion 14, a seat back 16 erected above the rear end of the seat cushion 14, and a headrest 18 connected to the upper end of the seat back 16. The front-rear, left-right, top-bottom directions of the vehicle seat 12 coincide with the front-rear, left-right, top-bottom directions of the vehicle.

[0022] 1 to 5, a crash test dummy D is shown seated on a seat cushion 14 of a vehicle seat 12 as a model of an occupant (seater) to be protected. The dummy D is, for example, an AM50 (50th percentile of American adult males) frontal crash test dummy (Hybrid III). The dummy D is seated in a standard seating position defined by the crash test method, and the vehicle seat 12 is located at a reference setting position corresponding to the seating position. Hereinafter, for ease of understanding, the dummy D will be referred to as an "occupant D."

[0023] An occupant D seated on the seat cushion 14 of the vehicle seat 12 is restrained to the vehicle seat 12 by a seat belt 22 (see Figs. 1 to 3; not shown in Figs. 4 and 5) provided in a seat belt device 20. The seat belt device 20 is a three-point seat belt device, and is a so-called seat-mounted seat belt device in which a retractor, an anchor, and a buckle (reference numbers omitted) (not shown) are provided on the vehicle seat 12.

[0024] The airbag device 30 includes an airbag 32, an inflator 60 (see FIG. 2), and a diffuser 62 (see FIGS. 2 and 3). The airbag 32 is normally stored in a folded state together with the inflator 60 and the diffuser 62 in a module case (not shown). The module case is disposed behind the upper part of the vehicle seat 12 (more specifically, behind the upper end of the seat back 16 and the headrest 18) and is fixed to the upper end of the seat back 16 or to the vehicle body (not shown).

[0025] The airbag 32 receives gas from the inflator 60 and inflates (deploys and inflates) from the rear side of the upper part of the vehicle seat 12 to the front side. The airbag 32 has a front-rear chamber 34, a push-out chamber 39, and an airbag body 40. The front-rear chamber 34 has a pair of left and right front-rear extending parts 34A that inflate and deploy forward through both the left and right sides of the head H of the occupant D, and a connecting part 34B that connects the front ends of the pair of front-rear extending parts 34A in the left-right direction. The push-out chamber 39 inflates and deploys above the headrest 18 and connects the rear ends of the pair of front-rear extending parts 34A in the left-right direction. The airbag body 40 inflates and deploys toward the occupant D side (rear side) behind the front-rear chamber 34 and behind the connecting part 34B.

[0026] The front and rear chambers 34 are formed into a long bag shape by overlapping two long pieces of base fabric 36, 38 shown in FIG. 6 and sewing the peripheral parts at the sewing part S1. The extrusion chamber 39 is formed into a long bag shape by overlapping two long pieces of base fabric and sewing the peripheral parts at the sewing part, although not shown. The airbag main body 40 is formed into a bag shape by folding one piece of base fabric 42 shown in FIG. 7 along four fold lines L1, L2, L3, and L4 and sewing at the sewing part S2. At the sewing part S2, the sewing line SL21 and the sewing line SL22 are sewn, the sewing line SL23 and the sewing line SL24 are sewn, the sewing line SL25 and the sewing line SL26 are sewn, and the sewing line SL27 and the sewing line SL28 are sewn. The base fabrics 36, 38, 42 and the base fabric of the extrusion chamber 39 are made of, for example, a nylon or polyester fabric material. One or both of the two base fabrics 36, 38 constituting the front and rear chambers 34 is made of a base fabric that is less stretchable than the base fabric 42 constituting the airbag body 40.

[0027] Both longitudinal ends of the front-rear chamber 34 are a pair of front-rear extending portions 34A, and the longitudinal center of the front-rear chamber 34 is a connecting portion 34B. Each of the pair of front-rear extending portions 34A is formed in a long tubular shape. The connecting portion 34B is in the shape of a substantially T-shaped bag that is connected to each of the front-rear extending portions 34A. Both longitudinal ends of the extrusion chamber 39 are connected to the end portions (rear end portions) of the pair of front-rear extending portions 34A on the opposite side to the connecting portion 34B. The extrusion chamber 39 is connected to the pair of front-rear extending portions 34A.

[0028] The connecting portion 34B of the front and rear chambers 34 is sewn to the airbag body 40 at a sewn portion S3 (see Figs. 6 and 7) provided in the center of the connecting portion 34B. The sewn portion S3 has a substantially inverted trapezoidal shape, for example. A communication hole 48 that connects the inside of the connecting portion 34B to the inside of the airbag body 40 is formed on the inside of the sewn portion S3. The communication hole 48 has a substantially inverted trapezoidal shape, for example. The communication hole 48 is composed of a through hole 50 formed in the base fabric 36 of the front and rear chambers 34 and a through hole 52 formed in the base fabric 42 of the airbag body 40.

[0029] The front and rear chambers 34, the extrusion chamber 39, and the airbag body 40 are normally folded in a predetermined manner such as roll folding or bellows folding and housed in the module case. Gas is supplied from an inflator 60 to the pair of front and rear extending portions 34A of the front and rear chambers 34 and the extrusion chamber 39 via a diffuser 62, which will be described in detail later. The inflator 60 is a combustion-type or cold gas-type cylinder-type inflator, and generates gas when activated. The activation of this inflator 60 is controlled by a control device (not shown), and generates gas when the vehicle collides.

[0030] The inflator 60 is disposed at the top of the vehicle seat 12 (here, behind the upper end of the seat back 16) with its axial direction aligned with the up-down direction of the seat back 16. The inflator 60 is provided with, for example, a pair of upper and lower stud bolts. The pair of stud bolts penetrate, for example, a frame (not shown) of the seat back 16, and a nut is screwed onto each stud bolt. In this way, the inflator 60 is fixed to the frame of the seat back 16.

[0031] When the inflator 60 is activated, gas generated from the gas ejection portion 60A provided at the upper end of the inflator 60 is supplied to the pair of front and rear extending portions 34A and the extrusion chamber 39 through the diffuser 62. As a result, the pair of front and rear extending portions 34A and the extrusion chamber 39 begin to inflate and deploy. The gas supplied to the pair of front and rear extending portions 34A and the extrusion chamber 39 flows toward the connecting portion 34B side and is supplied to the airbag body 40 through the communication hole 48. As a result, the airbag body 40 inflates and deploys after the front and rear chambers 34 and the extrusion chamber 39. When the airbag 32 inflates and deploys, a tear line (not shown) formed on the module case is configured to tear under the inflation pressure of the airbag 32. As a result, the airbag 32 can inflate and deploy to the outside of the module case.

[0032] The pair of inflated and deployed front-rear extending portions 34A extend in the front-rear direction on both the left and right sides of the head H of the occupant D, and face the head H from both the left and right sides with a gap therebetween. The pair of front-rear extending portions 34A are pulled diagonally downward toward the rear by a pair of left and right rear tethers 54 (described later), and thus assume a posture inclined downward toward the front. The front ends of the pair of inflated and deployed front-rear extending portions 34A are connected in the left-right direction by the inflated and deployed connecting portion 34B. As shown in FIG. 3, the front-rear chamber 34 including the pair of front-rear extending portions 34A and the connecting portion 34B is inflated and deployed in a U-shape that opens rearward in a plan view.

[0033] As shown in FIG. 1, FIG. 2, FIG. 4, and FIG. 5, the expanded portion 34B1 is provided at the left-right center of the inflated and deployed connecting portion 34B, and has a larger vertical dimension than both left and right ends of the connecting portion 34B. The expanded portion 34B1 protrudes downward from both left and right ends of the connecting portion 34B. The aforementioned communication hole 48 is formed in the expanded portion 34B1. The communication hole 48 is located at the rear side of the left-right center of the inflated and deployed connecting portion 34B. Gas from the inflator 60 is supplied rearward through the communication hole 48 into the airbag body 40. As a result, the airbag body 40 is inflated and deployed toward the occupant D side (rear side) behind the front and rear chambers 34 behind the connecting portion 34B. The airbag body 40 passes through the gap between the head H of the occupant D and the ceiling of the vehicle (not shown) from the rear side to the front side due to the inflation and deployment of the front and rear chambers 34, and then inflates and deploys toward the rear side.

[0034] During the passage, the airbag body 40 is pushed forward by the push-out chamber 39, which inflates and deploys before the airbag body 40, and the forward inflation and deployment of the airbag body 40 is promoted. The inflated and deployed airbag body 40 faces the head H, chest C, and abdomen B of the occupant D from the front side with a gap therebetween. As a result, the occupant D, who moves forward due to inertia caused by the impact of the vehicle collision, is restrained from the front side by the inflated and deployed airbag body 40. During this occupant restraint, the front and rear chambers 34 are expanded in the front and rear directions, and the airbag body 40 is compressed in the front and rear directions. The airbag body 40 is shaped so that it is sandwiched between the thighs T and chest C of the occupant D from the middle to the latter stages of the occupant restraint.

[0035] As shown in Figs. 1 to 6, a pair of left and right rear tethers 54, a pair of left and right front upper tethers 56, and a pair of left and right front lower tethers 58 are attached to the airbag 32. The rear tethers 54, the front upper tethers 56, and the front lower tethers 58 are formed in long strips from, for example, a nylon or polyester cloth material. The cloth materials forming the rear tethers 54, the front upper tethers 56, and the front lower tethers 58 are configured to be less stretchable than the base cloths 36, 38 forming the front and rear chambers 34 and the base cloth 42 forming the airbag body 40. This resistance to stretching can be adjusted by the material and thickness of the cloth.

[0036] One end of each of the pair of rear tethers 54 is engaged (sewn) to a longitudinal intermediate portion of the pair of front-rear extending portions 34A (specifically, to a front portion of each of the inflated and deployed front-rear extending portions 34A). The other end of each of the pair of rear tethers 54 is engaged to the seat back 16 or the vehicle body (not shown) on the rear side of the occupant D. When the airbag 32 is in an inflated and deployed state, the pair of rear tethers 54 extend in the front-rear direction below the pair of front-rear extending portions 34A. In this state, the pair of rear tethers 54 are inclined so as to descend toward the rear. As a result, the pair of front-rear extending portions 34A are configured to be pulled diagonally downward toward the rear by the pair of rear tethers 54. As a result, when the airbag 32 is fully inflated and deployed, the airbag 32 is suppressed from swinging in the up-down direction and the front-rear direction.

[0037] As described above, the pair of front and rear extending portions 34A are retracted, and thus, when the airbag 32 restrains the occupant, the lower surfaces of the pair of front and rear extending portions 34A come into contact with the left and right shoulders K of the occupant D. When the airbag 32 restrains the occupant, the airbag body 40 is supported by the tensile load of the pair of front and rear extending portions 34A and the pair of rear tethers 54. In this embodiment, the occupant D is AM50, but even when the occupant D is AM95 (the 95th percentile of American adult males) or AF05 (the 5th percentile of American adult females), the length of the pair of rear tethers 54 is set so that the lower surfaces of the pair of front and rear extending portions 34A come into contact with the left and right shoulders K of the occupant D.

[0038] The pair of front upper tethers 56 connect the left and right sides of the front of the upper part of the airbag body 40 that inflates and deploys above the front and rear chambers 34 to the front of the pair of front and rear extending parts 34A. One end of each of the pair of front upper tethers 56 is sewn to the left and right sides of the front of the upper part of the airbag body 40 that inflates and deploys above the front and rear chambers 34. The other end of each of the pair of front upper tethers 56 is sewn to the front of the pair of front and rear extending parts 34A. The pair of front upper tethers 56 prevent the airbag body 40 from rotating upward around the connecting parts 34B when the airbag 32 is fully inflated and deployed.

[0039] The pair of front lower tethers 58 connect the left and right portions of the lower part of the airbag body 40 that inflates and deploys downward from the front and rear chambers 34 to the front portions of the pair of front and rear extending portions 34A. One end of each of the pair of front lower tethers 58 is sewn to the left and right portions of the lower part of the airbag body 40 that inflates and deploys downward from the front and rear chambers 34. The other end of each of the pair of front lower tethers 58 is sewn to the front portions of the pair of front and rear extending portions 34A. The pair of front lower tethers 58 suppress the airbag body 40 from rotating downward about the connecting portions 34B when the airbag 32 has completed inflation and deployment.

[0040] The airbag device 30 includes a control device (ECU) (not shown) that controls the operation of the inflator 60. The control device is electrically connected to the inflator 60 and a collision sensor (not shown). Based on information from the collision sensor, the control device is capable of detecting or predicting the occurrence of various types of frontal collisions (or the inevitability of a frontal collision) for the vehicle to which the control device is applied, for each of the collision types described below.

[0041] When the control device detects or predicts a frontal collision based on information from the collision sensor, it activates the inflator 60. The types of frontal collisions for which the control device activates the inflator 60 include offset frontal collisions such as a diagonal collision and a minute overlap collision, in addition to a full-wrap frontal collision.

[0042] 8 and 9, the diffuser 62 that distributes gas from the inflator 60 to the airbag 32 has a connection part 62A connected to the inflator 60 and a plurality of (three in this case) branched parts 62B branched from the connection part 62A, and is configured in a four-way branched tubular shape. The diffuser 62 is made of a heat-resistant material such as metal. The connection portion 62A is fixed to the inflator 60 with the upper end of the inflator 60 fitted inside. The three branch portions 62B are configured by a branch portion 62B1 extending upward from the connection portion 62A and having a tip portion bent forward above the headrest 18, a branch portion 62B2 extending leftward from the connection portion 62A and having a tip portion bent forward above the headrest 18, and a branch portion 62B3 extending rightward from the connection portion 62A and having a tip portion bent forward above the headrest 18. These branch portions 62B1, 62B2, and 62B3 are arranged to extend forward from the rear side of the headrest 18, avoiding the headrest 18.

[0043] The tip of the branch portion 62B1 extended upward is inserted into a connection hole (not shown) formed in the longitudinal center of the extrusion chamber 39. The edge of the connection hole in the extrusion chamber 39 is fixed to the tip of the branch portion 62B1 using, for example, a metal band. The tip of the branch portion 62B2 extended to the left is inserted into a connection hole (not shown) formed in the rear end of the left front-rear extension portion 34A. The edge of the connection hole in the left front-rear extension portion 34A is fixed to the tip of the branch portion 62B2 using, for example, a metal band. The tip of the branch portion 62B3 extended to the right is inserted into a connection hole (not shown) formed in the rear end of the right front-rear extension portion 34A. The edge of the connection hole in the right front-rear extension portion 34A is fixed to the tip of the branch portion 62B3 using, for example, a metal band.

[0044] In the above-mentioned diffuser 62, the branch portion 62B1 communicates with the extrusion chamber 39, the branch portion 62B2 communicates with the left front-rear extending portion 34A, and the branch portion 62B3 communicates with the right front-rear extending portion 34A. This allows the gas generated from the gas ejection portion 60A of the inflator 60 to pass through the branch portions 62B1, 62B2, and 62B3 and be distributed to the extrusion chamber 39 and the left and right front-rear extending portions 34A.

[0045] A plurality of (here, a large number of) partition walls 66 are provided inside the diffuser 62. Specifically, the partition walls 66 are provided inside the connecting portion 34B and inside the three branch portions 62B. The large number of partition walls 66 constitute a sound absorbing portion 64. The interior of the diffuser 62 is divided into a plurality of (here, a large number of) chambers 68 that communicate with each other by the large number of partition walls 66. Each partition wall 66 is made of, for example, a metal, and has a truncated cone shape (a shape like a coned disc spring) that is inclined (reduced in diameter) toward the downstream side of the flow direction F of the gas flowing inside the diffuser 62. An opening (reference numeral omitted) is formed in the center of each partition wall 66, and the multiple chambers 68 communicate with each other through the opening of each partition wall 66. As a result, the diffuser 62 functions as a partition type sound absorbing device, and is configured to reduce the sound pressure of the gas from the inflator 60.

[0046] (Action and Effects) Next, the operation and effects of this embodiment will be described.

[0047] The occupant protection device 10 according to this embodiment includes a vehicle seat 12 on which an automobile occupant D sits, and an airbag device 30 that protects the occupant D in the event of a vehicle collision. In this airbag device 30, in the event of a vehicle collision, gas generated from an inflator 60 mounted on the upper part of the vehicle seat 12 is guided to a diffuser 62 and distributed to an airbag 32, which inflates and deploys from the upper part of the vehicle seat 12 forward.

[0048] The diffuser 62 has a connection portion 62A connected to the inflator and a plurality of branch portions 62B branched from the connection portion 62A and connected to the airbag 32, and the gas is distributed to a plurality of locations in the airbag 32 through the plurality of branch portions 62B. In this diffuser 62, the connection portion 62A and the plurality of branch portions 62B are provided with sound-deadening portions 64 (a large number of partition walls 66) for reducing the sound pressure of the gas. Therefore, even if the connection portion 62A and the plurality of branch portions 62B are each set to a small diameter, the sound pressure of the gas is reduced at the connection portion 62A and the plurality of branch portions 62B, so that sound-deadening performance can be ensured. As a result, even in a configuration in which the inflator 60 is mounted near the headrest 18, which is close to the ears of the occupant D, it is possible to prevent adverse effects on the ears of the occupant D. Moreover, the plurality of branch portions 62B set to a small diameter can be arranged to fit the space above the vehicle seat 12, so that the mountability at the upper portion of the vehicle seat 12 can be improved. Furthermore, since the diffuser 62 that distributes gas to a plurality of locations in the airbag 32 functions as a silencer, the task of fixing a dedicated silencer to the inflator 60 is eliminated.

[0049] In this embodiment, the airbag 32 has a front-rear chamber 34, a push-out chamber 39, and an airbag body 40. The front-rear chamber 34 includes a pair of left and right front-rear extending portions 34A that inflate and deploy forward through the left and right sides of the head H of the occupant D seated in the vehicle seat 12. The push-out chamber 39 inflates and deploys above the headrest 18, and connects the rear ends of the pair of front-rear extending portions 34A in the left-right direction. The airbag body 40 is supplied with gas from the inflator 60 through the front-rear chamber 34, and inflates and deploys in front of the occupant D. The multiple branch portions 62B of the diffuser 62 are connected to the pair of front-rear extending portions 34A and the push-out chamber 39. This allows the gas from the inflator 60 to be distributed to the pair of front-rear extending portions 34A and the push-out chamber 39, respectively, so that the mounting space, manufacturing costs, and number of parts can be reduced compared to a configuration in which gas is supplied from separate inflators to the pair of front-rear extending portions 34A and the push-out chamber 39, respectively.

[0050] In this embodiment, the front and rear chambers 34 include a connecting portion 34B that connects the front ends of the pair of front and rear extending portions 34A in the left-right direction, and the airbag body 40 inflates and deploys toward the occupant D behind the front and rear chambers 34 on the rear side of the connecting portion 34B. When the occupant D is restrained, the airbag body 40 is compressed in the front and rear direction while expanding the front and rear chambers 34 in the front and rear direction. This compressive deformation of the airbag body 40 can improve energy absorption performance.

[0051] In this embodiment, the sound absorbing section 64 is formed by a plurality of partition walls 66 provided inside the diffuser 62, and the inside of the diffuser 62 is divided into a plurality of chambers 68 that communicate with each other by the plurality of partition walls 66. This allows the diffuser 62 to function as a partition-type sound absorbing device, thereby effectively reducing the sound pressure of the gas from the inflator 60. In addition, the plurality of partition walls 66 also function as reinforcing members that reinforce the diffuser 62, allowing the wall thickness of the diffuser 62 to be thin.

[0052] Moreover, each partition 66 has a truncated cone shape that is inclined (reduced in diameter) toward the downstream side in the flow direction F (see FIG. 10) of the gas flowing inside the diffuser 62. Therefore, it is possible to suppress the flow of gas flowing inside the diffuser 62 from being obstructed by the partition 66.

[0053] In the above embodiment, it is preferable to adjust the number of partitions 66, the inclination direction of the partitions 66, and the thicknesses of the diffuser 62 and the partitions 66 in consideration of the gas flow, sound pressure, strength, etc. within the diffuser 62.

[0054] In addition, as in a modified example shown in FIG. 11, for example, the sound absorbing section 70 may be formed by a plurality of partition walls 72 that are inclined toward the downstream side of the flow direction F of the gas flowing inside the diffuser 62 and are arranged offset from one another in the flow direction F.

[0055] In addition, in the above embodiment and modified example, the sound absorbing portions 64, 70 are configured by a plurality of partition walls 66, 72 provided inside the diffuser 62, but the present invention is not limited to this. The sound absorbing portions may be, for example, glass wool or steel wool provided inside the diffuser 62.

[0056] In the above embodiment, the airbag 32 has the front and rear chambers 34, the push-out chamber 39, and the airbag body 40, but the configuration of the airbag 32 can be changed as appropriate. For example, the airbag 32 can be changed to a configuration having the left and right front and rear chambers 34 and the airbag body 40 without having the push-out chamber 39.

[0057] In addition, the present invention can be implemented in various modifications without departing from the spirit and scope of the present invention. Furthermore, the scope of the present invention is not limited to the above-described embodiment. [Explanation of symbols]

[0058] 10 Occupant protection devices 12 Vehicle seats 30 Airbag device 32 Airbag 34 Front and rear chambers 34A Front and rear extension part 34B Connection part 40 Airbag body 60 Inflator 62 Diffuser 62A Connection 62B Branch 64 Silencer 66 Bulkhead 68 rooms 70 Silencer 72 Bulkhead D. Crew H head

Claims

1. An inflator that is mounted on an upper portion of a vehicle seat and generates gas in the event of a vehicle collision; an airbag that is supplied with the gas and inflates and deploys from the upper portion toward the front side of the seat; a diffuser having a connection part connected to the inflator and a plurality of branch parts branching from the connection part and respectively connected to the airbag, distributing the gas to the airbag and having a muffling part provided at least in the plurality of branch parts for reducing a sound pressure of the gas; An airbag device comprising:

2. The airbag is a front and rear chamber including a pair of left and right front and rear extending portions that inflate and deploy toward a front side of the seat through both left and right sides of a head of an occupant seated in the vehicle seat; an airbag body that is supplied with the gas through the front and rear chambers and inflates and deploys in front of the occupant; having The airbag device according to claim 1 , wherein the plurality of branch portions of the diffuser are connected to at least the pair of front and rear extending portions.

3. The front and rear chambers include a connecting portion that connects front end portions of the pair of front and rear extending portions in the seat left-right direction, The airbag device according to claim 2, wherein the airbag body inflates and deploys toward the occupant on the seat rear side of the connecting portion after the front and rear chambers inflate and deploy.

4. the muffling section is a plurality of partition walls provided inside the diffuser, 4. The airbag device according to claim 1, wherein an interior of the diffuser is divided into a plurality of chambers that are in communication with one another by the plurality of partition walls.

5. 5. The airbag device according to claim 4, wherein the partition is inclined toward a downstream side in a flow direction of the gas flowing inside the diffuser.

6. A vehicle seat for a passenger to sit in; The airbag device according to any one of claims 1 to 3, which is mounted on an upper portion of the vehicle seat; An occupant protection device comprising:

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