Patent ID: 12240403

DESCRIPTION OF EMBODIMENTS

Hereinafter, an airbag attachment structure10according to an embodiment of the invention will be described with reference to the accompanying drawings.

First, an instrument panel2of a vehicle1such as an automobile to which the airbag attachment structure10is applied will be described with reference toFIGS.1,2and3.FIG.1is a perspective view of the instrument panel2.FIG.2is a view of the airbag attachment structure10inFIG.1as viewed from a back surface of the instrument panel2.FIG.3is a view corresponding to a cross section taken along a line III-III inFIG.2, and is a cross-sectional view illustrating the airbag attachment structure10.

As illustrated inFIG.1, the instrument panel2is provided at a front part of a vehicle cabin of the vehicle1. The vehicle1includes an airbag device3.

The airbag device3is a safety device for protecting an occupant in an emergency such as a collision of the vehicle1. The airbag device3is provided at a part of the instrument panel2on a front passenger seat side, and protects an occupant sitting on a front passenger seat. The airbag device3includes an airbag module4(seeFIG.3) and the airbag attachment structure10.

Examples of the airbag device3include an airbag for a driver seat, an airbag for a front passenger seat, a side airbag, and a curtain airbag. In the present embodiment, the airbag device3is an airbag for a front passenger seat.

As illustrated inFIG.3, the airbag module4includes an airbag4a, an airbag case4b, a plurality of hooks4c, and an inflator4d.

The airbag4ais formed in a bag shape, and is folded and stored in the airbag case4b. The airbag4ais deployed and inflated in an emergency. The plurality of hooks4cfix the airbag case4bto the instrument panel2. The inflator4dgenerates gas for deploying and inflating the airbag4a.

As illustrated inFIG.1, the airbag attachment structure10is provided at a back surface of the instrument panel2on the front passenger seat side. Examples of the airbag attachment structure10include an integral type airbag attachment structure integrally provided with the instrument panel2, a separate type airbag attachment structure separately provided from the instrument panel2and attached to the instrument panel2. In the present embodiment, the airbag attachment structure10is an integral type airbag attachment structure and constitutes a part of the instrument panel2.

The instrument panel2normally covers the airbag module4from a front surface. The instrument panel2has a cleavage line6on the back surface thereof. In an emergency, the instrument panel2is cleaved from the cleavage line6due to a pressing force generated due to the deployed and inflated airbag4a, and an opening for the airbag4ato expand into the vehicle cabin is formed.

The cleavage line6is formed in a recessed shape from the back surface of the instrument panel2and has a groove shape that does not reach the front surface of the instrument panel2. The cleavage line6is provided into a substantially H shape and includes a lateral cleavage line portion6aextending substantially in a vehicle width direction, and left and right vertical cleavage line portions6bextending substantially in a vehicle longitudinal direction from both end portions of the lateral cleavage line portion6a. In the present embodiment, the cleavage line6further includes a pair of lateral cleavage line portions6ceach connecting corresponding end portions of the vertical cleavage line portions6b. In the instrument panel2, a pair of opening and closing portions7by which the opening can be formed are defined by the cleavage line6. The lateral cleavage line portion6ais located at a position to be first cleaved in the substantially H-shaped cleavage line6. The cleavage line6is formed only on a back surface side of the instrument panel2, and cannot be observed from a front surface of the instrument panel2.

Next, the airbag attachment structure10will be described with reference toFIGS.4to6.FIG.4is an enlarged view of a vicinity of the instrument panel2in a cross section taken along a line IV-IV inFIG.2.FIG.5is a perspective view illustrating the airbag attachment structure10as viewed from a back surface.FIG.6is a perspective view illustrating a state where a guide portion50and flaps60are removed from the airbag attachment structure10inFIG.5.

As illustrated inFIG.3, the airbag attachment structure10is a structure for attaching the airbag4ato the instrument panel2. The airbag attachment structure10includes an attachment portion20, a pair of hinge portions30, a pair of door portions40, the guide portion50, and the flaps60.

The attachment portion20is molded using a resin material. The attachment portion20has an opening20aat which the door portions40are opened and brought into an opened state when the airbag4ais deployed. The airbag case4bfor storing the airbag4ais attached to the attachment portion20via the hooks4c. The attachment portion20includes a main body21, a flange portion22, attachment holes23, and a plurality of reinforcing ribs24(seeFIGS.5and6).

As illustrated inFIGS.5and6, the main body21is formed in a substantially rectangular tubular shape. As illustrated inFIG.3, the opening20ais formed at one end portion21aof the main body21. The airbag module4is attached to the other end portion21bof the main body21.

The flange portion22is formed at an outer periphery of the one end portion21aof the main body21over the whole outer periphery. As illustrated inFIG.3, the flange portion22is attached to abut against the back surface of the instrument panel2. The flange portion22is welded to the back surface of the instrument panel2to reinforce the instrument panel2.

The attachment holes23penetrate the main body21in a thickness direction thereof. The hooks4cof the airbag module4are engaged with the attachment holes23in a manner of protruding from an inner side toward an outer side of the main body21. Accordingly, the airbag module4is attached to the attachment portion20.

As illustrated inFIGS.5and6, the plurality of reinforcing ribs24are arranged to an outer periphery of the flange portion22at intervals from each other. The reinforcing ribs24connect and reinforce the main body21and the flange portion22.

As illustrated inFIG.3, the pair of hinge portions30are provided to turnably hold the respective door portions40. The hinge portions30are integrally molded with the door portions40and the attachment portion20. Each of the hinge portions30is formed to protrude to an inner side of the opening20aso as to have a substantially U-shaped cross section. When the airbag4ais deployed and the door portions40are opened, each of the hinge portions30rotates with a connection point with the attachment portion20as a starting point while a part having the substantially U-shaped cross section is extending from the opening20ato the outside.

Hereinafter, a space surrounded by the door portions40, the airbag4a, and the attachment portion20is referred to as a “deployment passage8”.

The airbag4aprovided in the deployment passage8is inclinedly attached to the attachment portion20such that a distance to one of the hinge portions30is larger than a distance to the other of the hinge portions30. That is, the airbag4ais attached to the attachment portion20in a state where a deploying direction is not perpendicular to the door portions40but is inclined with respect to the door portions40.

The door portions40are integrally molded with the attachment portion20and the hinge portions30. One end portion41of each of the door portions40is provided along the lateral cleavage line portion6aof the instrument panel2. That is, each of the door portions40is provided such that at least the one end portion41is along the cleavage line6of the instrument panel2. Each of the door portions40is provided such that side end portions at both ends of the one end portion41are along the vertical cleavage line portions6bof the instrument panel2. The door portions40are attached to abut against the back surface of the instrument panel2. More specifically, a plurality of vibration welding ribs40bstanding outward are formed on an outer side of each of the door portions40, and tip portions of the vibration welding ribs40band the back surface of the instrument panel2are bonded by vibration welding.

The pair of door portions40are provided such that the one end portions41, which are free ends of the pair of door portions40, face each other on an inner side of the lateral cleavage line portion6a. When the airbag4ais deployed, each of the door portions40is opened such that the one end portion41turns around the corresponding hinge portion30. In each of the door portions40, a plurality of through holes45into which projection portions62formed at a tip of each of the flaps60are engaged are formed.

As illustrated inFIG.6, three through holes45are formed along an axial direction of a rotating shaft in each of the hinge portions30(also referred to as an extending direction in which each of the hinge portions30extend, and is a width direction of the vehicle1in a state where the airbag attachment structure10is attached in front of the front passenger seat of the vehicle1). As illustrated inFIG.3, in a state where the airbag4ais stored, that is, in a state before the airbag4ais deployed, the projection portions62formed at tip portions61of the flaps60are inserted into the through holes45.

The guide portion50is provided to protrude from the main body21of the attachment portion20to the deployment passage8. The guide portion50guides the deployment of the airbag4awhile reducing a volume of the deployment passage8. The guide portion50is molded using a resin material.

The guide portion50is formed to have higher rigidity than the flaps60. Here, the rigidity is the difficulty of deformation (magnitude of a deformation amount) when the airbag4ais deployed and is inflated and a pressure in the deployment passage8increases. That is, when the airbag4acomes into contact with the guide portion50and the flaps60in a state where an internal pressure of the airbag4ais increased in the deployment passage8, the guide portion50is less likely to be deformed as compared with the flaps60(the deformation amount is small). More specifically, the guide portion50includes reinforcing ribs56on a back surface that does not face the deployment passage8(seeFIG.7). Accordingly, the guide portion50is configured to have higher rigidity than the flap60.

The flap60is connected to the guide portion50at a connection point54and extends toward a corresponding one of the door portions40. The flap60linearly extends from the connection point54of the guide portion50to the deployment passage8, and is interposed between the airbag4aand the corresponding hinge portion30. At the tip portion61of the flap60on a door portion40side, three projection portions62(seeFIG.7) extend linearly along the extending direction of the flap60.

The flaps60are biased and bent by the airbag4awhen the airbag4ais deployed, and turn together with the door portions40around the connection points54during deployment of the airbag4a. Since the flaps60are provided between the airbag4aand the hinge portions30, the pressure generated due to the inflation of the airbag4acan be concentrated between the pair of door portions40(the lateral cleavage line portion6a) when the airbag4ais deployed, and the damage to the hinge portions30can be prevented by preventing the airbag4afrom coming into direct contact with the rotating shafts of the hinge portions30.

The flap60is integrally molded with the guide portion50. Instead, the guide portion50and the flap60may be separately formed and assembled. In this case, by molding the guide portion50and the flap60using different materials or to have different thicknesses, the rigidity of the guide portion50can be made higher than that of the flap60.

Next, a connection structure of the door portion40and the flap60will be described with reference toFIGS.7and8.

FIG.7is a perspective view of the guide portion50and the flap60as viewed from a side being in contact with the main body21.FIG.8is a perspective view of the guide portion50and the flap60as viewed from a deployment passage8side.

As illustrated inFIG.7, the flap60that linearly extends in a flat plate shape from the connection point54is provided on the guide portion50. At the tip portion61of the flap60, three projection portions62are formed to further protrude from the tip portion61in an extending direction of the flap60. Further, the guide portion50includes the lattice-shaped reinforcing ribs56on the back surface thereof that does not face the deployment passage8.

As illustrated inFIG.3, in each of the door portions40, the through holes45each penetrating from an inner side to an outer side of the door portion40at an inclination from a hinge portion30side to a one end portion41side of the door portion40are formed. An inclination direction of the through holes45is set to be substantially the same as the extending direction of the projection portions62of the flap60extending from the guide portion50in a state where the guide portion50is attached to the main body21. That is, the through holes45are formed to be inclined at an acute angle of 90 degrees or less with respect to the back surface of the corresponding door portion40.

With such a configuration, in the state where the guide portion50is fixed to the main body21, the projection portions62protruding from the tip portion61of the flap60are respectively inserted into the through holes45formed in the door portion40.

Here, each of the projection portions62is disposed such that a tip thereof (an end portion on a side separated farthest from the tip portion61) is located at a position that does not reach a front surface side of the through hole45formed to penetrate the door portion40, that is, a position that does not come into contact with the back surface of the instrument panel2. In addition, as illustrated inFIG.4, the tip portion61of the flap60other than the three projection portions62is not in contact with the back surface of the door portion40. That is, a gap is formed between the tip of the projection portion62and the back surface of the instrument panel2, and a gap is formed between the tip portion61of the flap60other than the projection portions62and the back surface of the door portion40.

Therefore, at the tip portion61of the flap60, only the projection portions62are in contact with the through holes45of the door portion40, and other portions of the tip portion61are not in contact with the door portion40.

According to such a configuration, the flap60is held by the door portion40such that the projection portions62are respectively inserted into the through holes45in the extending direction of the flap60.

Here, in the related art, as a method for fixing the flaps60to the door portions40, the ribs provided on the tip portions61of the flaps60are engaged with grooves provided on the back side of the door portions40, and thus positions of the flaps60are determined. In such a structure, the ribs may be engaged with the grooves in a state where the flaps60are formed to be larger than a design dimension due to, for example, an error during manufacturing. In such a case, a force is applied in a direction that the flaps60push up the door portions40, and the door portions40push up the instrument panel2fixed on an outer side of the door portions40, and thus an outline of the cleavage line6may rise up on the front surface of the instrument panel2.

Meanwhile, in each of the flaps60according to the invention, the projection portions62protruding from the tip portion61are respectively inserted into the through holes45in the extending direction of the flap60and are freely movable with respect to the door portion40in an inserting direction. Accordingly, even if a positional relation between the flap60and the door portion40changes, the flap60is freely movable with respect to the door portion40in the extending direction of the flap60, so that it is possible to prevent the force from acting in the direction where the door portions40are pushed up. Further, since the door portions40and the back surface of the instrument panel2are fixed via the vibration welding ribs40b, it is possible to largely secure the gap between the back surface of the instrument panel2and the projection portions62by an amount corresponding to a height of the vibration welding ribs40b, and it is possible to prevent the tips of the projection portions62from interfering with the back surface of the instrument panel2.

Next, a configuration of each of the projection portions62of the flap60will be described with reference toFIGS.9to11.

FIG.9is an enlarged view of a front surface of the projection portion62(a surface of the flap60opposite to the deployment passage8), andFIG.10is an enlarged view of a back surface of the projection portion62(a surface of the flap60on the deployment passage8side, that is, a surface facing the airbag4a).FIG.11is a cross-sectional view of the door portion40in a state where the projection portion62is fitted into the through hole45.

As illustrated inFIGS.9and10, the projection portion62protrudes in a rectangular shape from the tip portion61of the flap60. The projection portion62has, on a front surface and a back surface thereof, ribs enlarged in a thickness direction thereof. Two ribs62aand62bare formed on the front surface of the projection portion62, and two ribs62cand62dare formed on the back surface of the projection portion62. Further, in addition to the two ribs62cand62dserving as a first rib, a rib62eserving as a second rib, which is enlarged in the thickness direction toward a back surface side, is formed at an outer periphery portion on the back surface of the projection portion62.

The projection portion62is enlarged in the thickness direction thereof due to the ribs62aand62bon the front surface and the ribs62c,62d, and62eon the back surface. The ribs62aand62bon the front surface and the ribs62cand62don the back surface of the projection portion62are in contact with an inner side of the through hole45near a center of the through hole45in a width direction thereof, and the rib62eis in contact with the inner side of the through hole45near end portions of the through hole45in the width direction thereof. Since the projection portion62includes these ribs, the projection portion62is more closely fitted in the through hole45of the door portion40in the width direction (in the width direction from the back surface to the front surface of the door portion40). According to such a configuration, it is possible to eliminate a backlash between the projection portion62and the through hole45, and it is possible to prevent generation of abnormal noise that is generated by the projection portion62and the through hole45, even when the vehicle1travels and vibrates. A height of these ribs in the thickness direction is formed to such a height that the projection portion62is easily removed from the through hole45of the door portion40when the airbag4ais deployed and the door portion40is opened as described later.

Instead of forming the ribs on the projection portion62, ribs standing toward the projection portion62may be formed on the inner side of the through hole45, and the ribs may be in contact with the projection portion62, or ribs may be formed in both of the projection portion62and the through hole45so as to come into contact with each other.

Further, as illustrated inFIG.11, the through hole45of the door portion40includes, on a side facing a back surface side (a deployment passage8side) thereof, a thin portion45aformed to have a thin thickness shape in the thickness direction of the door portion40. A thickness B of the thin portion45ais smaller than a thickness A of other portions of the door portion40. Due to the thin portion45a, an opening area of the through hole45decreases stepwise from the inner side to the outer side of the door portion40. Due to such a shape in which the opening area of the through hole45increases on the inner side of the door portion40, when the projection portion62of the flap60is inserted into the through hole45of the door portion40, the insertion is facilitated and operability is enhanced. Further, when the airbag4ais deployed and the door portion40is opened, the projection portion62can be easily removed from the through hole45of the door portion40.

The flap60and the guide portion50are formed using a resin material by injection molding. For the formation, a parting line60L is formed on the flap60. As illustrated inFIG.9, the parting line60L is formed at one position in the thickness direction of the flap60in a direction surrounding the flap60. At the parting line60L, the resin material may protrude outward, that is, a so-called burr may be formed.

Here, when the airbag4ais deployed and the projection portions62of the flaps60are removed from the through holes45of the door portions40, the airbag4acomes into contact with the flaps60and the back surface side of the projection portions62. At this time, when the burr is formed at each of the parting lines60L of the projection portions62of the flaps60, the parting lines60L may come into contact with the airbag4a.

Here, as illustrated inFIG.9, in the projection portion62according to the present embodiment, the parting line60L is formed on the back surface of the flap60, that is, a side surface close to a surface side opposite to the surface facing the airbag4a(a side close to the instrument panel2). According to such a configuration, the airbag4ais prevented from coming into direct contact with the parting lines60L during deployment of the airbag4a.

Next, the door portions40and the flaps60during deployment of the airbag4awill be described.FIG.12is a cross-sectional view illustrating the airbag4ain a state during deployment.FIG.13is also a cross-sectional view illustrating the airbag4ain a state during deployment.

In an emergency such as a collision of the vehicle1, in response to a signal from a sensor (not shown) that detects the collision, the airbag device3operates to protect the occupant sitting on the front passenger seat. When the airbag device3operates, the airbag4ais deployed and inflated by the gas generated by the inflator4dso as to press the back surface of the instrument panel2.

Here, a case (comparative example) where no guide portion is provided and only the flaps are attached to the attachment portion will be discussed. In this case, the flaps are disposed in the deployment passage defined by an upper surface of the airbag and the main body of the attachment portion. When the airbag is deployed and inflated, the flaps are bent, and the pressure cannot be accordingly concentrated on a cleavage line portion between the door portions. In particular, when the flaps are attached to the attachment portion, the flaps are bent to rotate respectively with contact positions with the attachment portion, which serve as base portions of the flaps, as starting points, and thus a bending amount increases.

In the airbag attachment structure10according to the present embodiment, the guide portion50having higher rigidity than the flap60is provided to protrude from the attachment portion20so as to narrow the deployment passage8, and the flap60is connected to the guide portion50. Accordingly, since the guide portion50having higher rigidity reduces a volume of the deployment passage8, when the airbag4ais inflated, the pressure can be concentrated between the door portions40(the lateral cleavage line portion6a). Further, since the flap60is connected to the guide portion50protruding from the attachment portion20, the flap60can be reduced in size. Therefore, the bending of the flap60is reduced by an amount corresponding to the reduction in size of the flap60, so that the pressure when the airbag4ais inflated is easily concentrated between the door portions40.

When the airbag4ais inflated and the pressure in the deployment passage8increases, as illustrated inFIG.12, the airbag4apresses the back surfaces of the door portions40, and the door portions40move in a direction in which the door portions40turn around the respective hinge portions30. Accordingly, the instrument panel2is cleaved from the cleavage line6, and the opening and closing portions7are opened.

At this time, since the projection portions62are respectively inserted into the through holes45of the door portion40in a turning direction of the turning door portion40, as illustrated inFIG.13, the projection portions62are easily removed from the through holes45as the door portion40turns.

According to the embodiment described above, the following effects are achieved.

The airbag attachment structure10for attaching the airbag4ato the instrument panel2includes: the door portions40in each of which at least the one end portion41is welded to the back surface of the instrument panel2along the cleavage line6of the instrument panel2, and each of which is opened when the airbag4ais deployed; the attachment portion20to which the airbag case4bfor storing the airbag4ais attached and which has the opening20aat which the door portions40are opened and brought into an opened state when the airbag4ais deployed; the hinge portions30connected to the attachment portion20and configured to turnably hold the respective door portions40; and the flaps60interposed between the airbag4aand the hinge portions30, and configured to turn together with the respective door portions40when being biased by the airbag4aduring deployment of the airbag4a. In each of the door portions40, the through holes45each penetrating from an inner side to an outer side of the door portion40at an inclination of an acute angle from the hinge portion30side to the one end portion41side of the door portion40are formed. Each of the flaps60has, at the tip portion61thereof, the projection portions62inserted into the respective through hole45, and in the flap60, in a state where the projection portions62are inserted into the through holes45, a gap is formed between the back surface of the instrument panel2and the projection portion62, and a gap is formed between a position, which is the tip portion61of the flap60and at which no projection portion62is formed, and the inner side of the door portion40.

According to this configuration, the projection portions62are provided at the tip portion61of the flap60, the projection portions62are inserted into the through holes45each penetrating at an inclination of an acute angle, a gap is formed between the projection portion62and the instrument panel2, and a gap is formed between the tip portion61of the flap60other than the projection portions62, and the door portion40. According to such a configuration, the projection portion62of the flap60can be freely moved with respect to the through hole45in the door portion40in an inclination direction of an acute angle, and even in a case where the flap60is formed to be larger than a design dimension due to an error during manufacturing or the like, a force that presses the door portion40outward is not generated. Therefore, the door portions40are not pressed by the flaps60, and the cleavage line6is prevented from rising up on the instrument panel2.

Further, when the airbag4ais deployed and the cleavage line6is cleaved by the door portions40, the projection portions62are removed from the respective through holes45.

In this configuration, during deployment of the airbag4a, the projection portions62are removed from the through holes45, and the flaps60can cause the pressure generated due to the inflation of the airbag4ato be concentrated between the pair of door portions40. Further, the flaps60can prevent the airbag4afrom coming into direct contact with rotating shafts of the hinge portions30.

Further, at least one of the projection portion62and the through hole45is provided with ribs (62ato62e) that are in contact with the other of the projection portion62and the through hole45in the thickness direction of the projection portion62.

In this configuration, the ribs of each of the projection portions62are in contact with the corresponding through hole45, so that a gap between the projection portion62and the through hole45can be reduced to eliminate backlash, and generation of abnormal noise that is generated by the projection portions62and the through holes45can be prevented even when the vehicle1travels and vibrates.

Further, the ribs include a first rib (62c,62d) that is formed on the projection portion62and that is in contact with the inner side of the through hole45, and a second rib (62e) that is provided at an end portion of the through hole45in the width direction thereof with respect to the first rib and that is in contact with the through hole45.

In this configuration, the first rib is in contact with the inner side of the through hole45near the center of the through hole45in the width direction, and the second rib is in contact with the through hole45near the end portion, so that the projection portion62is more reliably fixed to the through hole45. Therefore, the gap between the projection portion62and the through hole45can be reduced to eliminate the backlash, and the generation of the abnormal noise that is generated by the projection portions62and the through holes45can be prevented even when the vehicle1travels and vibrates.

Further, during deployment of the airbag4a, each of the flaps60swings around the corresponding connection point54, and the flap60is linearly formed from the connection point54to the tip of the projection portion62.

In this configuration, when the airbag4ais deployed, the airbag4acomes into contact with the linear flaps60along surfaces, and causes the flaps60to turn around the respective connection points54, so that the flaps60can cause the pressure generated due to the inflation of the airbag4ato be concentrated between the pair of door portions40.

Further, the through hole45has the thin portion45awhich is thin on the back surface side of the door portion40, and the opening area of the through hole45decreases from the inner side to the outer side of the door portion40due to the thin portion45a.

In this configuration, since the opening area of the through hole45increases on the back surface side of the door portion40, the operability is enhanced when the projection portions62are inserted. The thin portion45amay have a shape in which the through hole45decreases in a tapered shape from the inner side to the outer side of the door portion40.

In addition, on the side surface of the projection portion62, the parting line60L is formed near the surface side opposite to the surface of the flap60facing the airbag4a.

In this configuration, during deployment of the airbag4a, the airbag4ais prevented from coming into direct contact with the parting line60L.

The guide portion50has higher rigidity than the flap60.

In this configuration, when the airbag4ais inflated, the guide portion50having higher rigidity is present in the deployment passage8, so that the pressure generated due to the inflation of the airbag4ais easily concentrated on the cleavage line6.

Embodiments of the present invention were described above, but the above embodiments are merely examples of applications of this invention, and the technical scope of this invention is not limited to the specific constitutions of the above embodiments.

The present application claims priority to Japanese Patent Application No. 2022-036645 filed on Mar. 9, 2022 to Japan Patent Office, the entire content of which is incorporated herein by reference.