Driver's airbag system

Abstract

To provide a driver's airbag system that can generate an appropriate reaction force for the driver. [Solution] The driver's airbag system is positioned in the center of the steering wheel and includes an airbag body that deploys beyond the rim of the steering wheel when deployed. In the airbag body, a plurality of gas vents are formed in the portion of the front base fabric that deploys beyond the rim, located on the side opposite the driver. The gas vents include a central hole located directly above the center of the steering wheel and a pair of first and second lateral holes located to the left and right of the central hole. The opening area of ​​the central hole is larger than the opening areas of the first and second lateral holes.

Description

Technical Field

[0001] The present invention relates to a driver airbag device.

Background Art

[0002] Patent Document 1 discloses a configuration of a driver airbag that is mounted on a boss portion near the center of a ring portion of a steering wheel, and is provided with vent holes capable of discharging inflation gas on left and right boss portion side walls.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of Invention

Problem to be Solved by the Invention

[0004] Meanwhile, the magnitude of the reaction force that the driver receives from the airbag main body differs between the case where the driver is caught on a vertical line passing through the center of the airbag main body and the case where the driver is caught offset left and right from this vertical line. Since the driver also receives the reaction force of this load, with a single gas discharge hole arranged symmetrically on each of the left and right sides, the reaction force received by the driver may not be optimized depending on the manner in which the driver is caught by the airbag main body.

[0005] An object of the present invention is to provide a driver airbag device capable of generating an appropriate reaction force for a driver.

Means for Solving the Problem

[0006] The driver's airbag device according to the present invention comprises an airbag body positioned in the central part of the steering wheel and deploying beyond the rim of the steering wheel when deployed. The airbag body has a rear base fabric located on the driver's side and a front base fabric located on the opposite side from the driver relative to the rear base fabric, and a plurality of gas discharge holes are formed in the portion of the front base fabric that deploys beyond the rim. The plurality of gas discharge holes include a central hole located at a position corresponding to directly above the center of the steering wheel, a first lateral hole positioned on one side in the vehicle width direction relative to the central hole and spaced apart from the central hole, and a second lateral hole positioned on the other side in the vehicle width direction relative to the central hole and spaced apart from the central hole, wherein the opening area of ​​the central hole is larger than the opening areas of the first lateral hole and the second lateral hole. [Effects of the Invention]

[0007] The above-described driver airbag system can generate an appropriate reaction force for the driver. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic diagram of the driver's airbag system according to the embodiment, viewed from the front of the vehicle. [Figure 2] This is a schematic front view showing the relationship between the airbag body and the rim. [Modes for carrying out the invention]

[0009] The driver's airbag system according to the embodiment will be described with reference to the drawings. Figure 1 is a view of the steering wheel 1 and the airbag body 2 of the airbag system as seen from the windshield side. In Figure 1, the steering wheel 1 is in a straight-ahead position with a steering angle of 0 degrees, and the airbag body 2 is in a fully deployed state. In Figure 1, the airbag body 2 is in the state before it catches the driver. Figure 1 shows the three gas discharge holes 3 of the airbag body 2 and the instrument panel 4.

[0010] The airbag system is mounted on the central boss of the steering wheel 1 as an airbag module to which an inflator (not shown) that receives an electrical signal during a collision and generates gas is attached. The airbag module may also be configured to function as a center horn button.

[0011] The steering wheel 1 comprises a boss plate (not shown) having a boss attached to the end of a steering column (not shown), a plurality of spokes (not shown) extending radially from the boss plate, and an annular rim 1R joined to the outer ends of the spokes. Note that there may be only one spoke. A resin cover is attached to the boss plate, and the spokes and rim are covered with foamed resin or the like. Various switches may be built into the spokes.

[0012] The airbag body 2 is formed into a bag shape by sewing together two circular base fabrics 2F and 2R around its circumference. The base fabrics 2F and 2R are made of woven fabric, and the inside or outside surface of the bag may be coated with resin or rubber. The two base fabrics 2F and 2R are the rear base fabric 2R, which is located on the driver's side, i.e., the rear of the vehicle, and the front base fabric 2F, which is located on the opposite side from the driver relative to the rear base fabric 2R, i.e., the front of the vehicle. An opening is formed in the center of the front base fabric 2F, and it is attached to the base plate of the module at this opening.

[0013] The airbag body, which is sewn together around the perimeter of the base fabrics 2F and 2R, is turned inside out using this opening, and the portion outside the perimeter seam is inside the bag. In addition, an opening is formed in the base plate to match the opening in the front base fabric 2F, and the inflator is attached to these openings. Furthermore, a tether belt or the like may be provided inside to define the shape, such as the thickness, of the airbag body 2 when fully deployed.

[0014] The outer diameter of the airbag body 2 is significantly larger than the outer diameter of the rim 1R. Therefore, the outer diameter of the airbag body 2 when fully deployed and inflated is also larger than the outer diameter of the rim 1R. As shown in Figure 1, the airbag body 2 extends beyond the rim 1R when deployed, and the inflated airbag body 2 that catches the driver is supported by the rim 1R. In addition, the inflated airbag body 2 that catches the driver is also supported by the spokes and by the boss plate via the module.

[0015] In this embodiment, three gas discharge holes 3 are formed in the portion of the front base fabric 2F that extends beyond the rim 1R, i.e., within the area indicated by dot hatching in Figure 2. The three gas discharge holes 3 include a central hole 30, a first lateral hole 31 positioned on one side of the central hole 30 in the vehicle width direction and spaced apart from the central hole 30, and a second lateral hole 32 positioned on the other side of the central hole 30 in the vehicle width direction and spaced apart from the central hole 30. The opening area of ​​the central hole 30 is larger than the opening area of ​​the first lateral hole 31 and larger than the opening area of ​​the second lateral hole 32.

[0016] In this embodiment, the distance between the central hole 30 and the first lateral hole 31 is equal to the distance between the central hole 30 and the second lateral hole 32. Also in this embodiment, the opening area of ​​the first lateral hole 31 is equal to the opening area of ​​the second lateral hole. The ratio of the opening areas of the first lateral hole 31 and the second lateral hole 32 to the opening area of ​​the central hole 30 is between 0.5 and 0.9.

[0017] Next, the position of the gas vent 3 relative to the steering wheel 1 will be explained with reference to Figure 2. Figure 2 is both a front view and a rear view of the airbag system when facing the rim 1R. In Figure 2, the positional relationship between the rim 1R, the airbag body 2, and the gas vent 3 is schematically shown, and all of these are shown with solid lines for clarity. Note that the airbag body 2 in Figure 2 is in the fully deployed state.

[0018] In this embodiment, as illustrated in Figure 2, the first and second lateral holes 31 and 32 are arranged such that, when viewed directly from the rim 1R, the central angle θ of the first and second lateral holes 31 with respect to the center O of the steering wheel 1 is between 60 degrees and 150 degrees. The central hole 30 is located on the bisector of the central angle θ. This bisector is contained within the vertical plane when the steering angle of the steering wheel 1 is in a straight line state.

[0019] Furthermore, the center O of the steering wheel 1 is the geometric center of the annular rim 1R and does not necessarily coincide with the rotation center of the steering wheel 1, i.e., the center of the boss. In addition, in the above-mentioned direct view, the center of the deployed airbag body 2 does not necessarily coincide with the center O of the steering wheel 1. The central angle θ is the angle formed when the center O is connected to the ends of an arc on the circumference of a circle with the first lateral hole 31 and the second lateral hole 32 as the ends of the arc.

[0020] (1) The driver airbag device according to the embodiment is positioned in the central part of the steering wheel 1 and includes an airbag body 2 that deploys beyond the rim 1R of the steering wheel 1 when deployed. The airbag body 2 has a rear base fabric 2R located on the driver side and a front base fabric 2F located on the opposite side from the driver relative to the rear base fabric 2R. A plurality of gas discharge holes 3 are formed in the portion of the front base fabric 2F that deploys beyond the rim 1R (see dot hunting in Figure 2). The plurality of gas discharge holes 3 include a central hole 30 located at a position corresponding to directly above the center of the steering wheel 1, a first lateral hole 31 positioned on one side in the vehicle width direction relative to the central hole 30 and spaced away from the central hole 30, and a second lateral hole 32 positioned on the other side in the vehicle width direction relative to the central hole 30 and spaced away from the central hole 30. The opening area of ​​the central hole 30 is larger than the opening area of ​​the first lateral hole 31 and the opening area of ​​the second lateral hole 32.

[0021] When the driver is received straight by the deployed airbag main body 2 without being offset left or right, the driver is received by the airbag main body 2 on a vertical line passing through the center thereof. In other words, the driver is received at the central portion of the airbag main body 2, and the airbag main body 2 itself is received by the entire circumference of the rim 1R, the spokes and the boss. According to the above configuration, the airbag main body 2 is crushed as the driver received at the central portion of the airbag main body 2 moves forward, and the gas inside the airbag main body 2 is rapidly discharged from the central hole 30 having a large opening area. Therefore, an excessive reaction force acting on the driver is suppressed, and the deployed airbag main body 2 can generate an appropriate reaction force on the driver.

[0022] In the event of a collision at a corner portion of the front portion of the vehicle, the driver does not move straight forward due to the inertial force at the time of collision, but is received obliquely by the airbag main body 2. That is, when the driver is received by the deployed airbag main body 2 with a left-right offset, the driver is received not at the central portion of the airbag main body 2 but biased to either the left or right side, and the airbag main body 2 is also received by the rim 1R biased to either the left or right side. In this case, if the gas inside the airbag main body 2 is discharged too quickly, the airbag main body 2 will deflate before sufficiently receiving the driver. According to the above configuration, a part of the airbag main body 2 is crushed as the driver moves obliquely forward, and the gas inside the airbag main body 2 is gently discharged from the first side hole 31 or the second side hole 32 having a small opening area. Therefore, the airbag main body 2 is prevented from deflating immediately, and the deployed airbag main body 2 can generate an appropriate reaction force on the driver.

[0023] (2) Further, in the embodiment, in a direct front view of the rim 1R, the central angle θ of the first side hole 31 and the second side hole 32 with respect to the center O of the steering wheel 1 is 60 degrees or more and 150 degrees or less. Further, the central hole 30 is arranged on the bisector of the central angle θ.

[0024] The airbag unit 2 primarily supports the driver's head in the upper half of its central region. If the central angle θ is less than 60 degrees, the three gas vents 3 become too close to each other, causing the gas to vent too quickly when the airbag unit 2 supports the driver in its central portion. In this case, the resulting reaction force may be lower than the appropriate reaction force. Also, if the airbag unit 2 supports the driver unevenly to either the left or right side, the gas venting will be delayed. In this case, the resulting reaction force may be higher than the appropriate reaction force.

[0025] If the central angle θ exceeds 150 degrees, the positions of the first lateral hole 31 and the second lateral hole 32 will be lower. As a result, when the airbag body 2 catches the driver with an imbalance to either the left or right side, gas discharge will be delayed. In that case, the resulting reaction force may be higher than the appropriate reaction force. Therefore, it is preferable that the gas discharge holes 3 be positioned such that the central angle θ is between 60 degrees and 150 degrees.

[0026] (3) Furthermore, in this embodiment, the opening area of ​​the first lateral hole 31 and the opening area of ​​the second lateral hole are the same. Also, the ratio of the opening area of ​​the first lateral hole 31 and the opening area of ​​the second lateral hole 32 to the opening area of ​​the central hole 30 is 0.5 or more and 0.9 or less.

[0027] If the above ratio is less than 0.5, the first and second lateral holes 31 and 32 are too small compared to the appropriate size of the central hole 30. As a result, when the airbag body 2 catches the driver with an imbalance to either the left or right side, the gas discharge from the first or second lateral hole 32 will be delayed. In this case, the resulting reaction force may be higher than the appropriate reaction force. Also, if the above ratio is less than 0.5, the central hole 30 is too large compared to the appropriate size of the first and second lateral holes 31 and 32. As a result, when the airbag body 2 catches the driver in its central portion, the gas discharge from the central hole 30 will be faster. In this case, the resulting reaction force may be lower than the appropriate reaction force.

[0028] If the above ratio exceeds 0.9, the difference between the size of the central hole 30 and the sizes of the first and second lateral holes 31 and 32 becomes smaller. Therefore, if the size of the central hole 30 is appropriate, when the airbag body 2 catches the driver with an bias to either the left or right side, gas will be expelled more quickly from the first or second lateral hole 31 or 32. In that case, the resulting reaction force may be lower than the appropriate reaction force. Also, if the sizes of the first and second lateral holes 31 and 32 are appropriate, when the airbag body 2 catches the driver in its central portion, gas will be expelled more slowly from the central hole 30. In that case, the resulting reaction force may be higher than the appropriate reaction force. Therefore, it is preferable that the above ratio be between 0.5 and 0.9.

[0029] As described above, embodiments of the present invention have been presented, but the statements and drawings that constitute part of this disclosure should not be understood as limiting the invention. Various alternative embodiments, examples, and operational techniques will become apparent to those skilled in the art from this disclosure. [Explanation of Symbols]

[0030] 1. Steering wheel 1R Rim 2. Airbag unit 2F Front base fabric 2R rear base fabric 3 Gas exhaust holes 30 center hole 31 1st lateral hole 32 2nd lateral hole O center θ central angle

Claims

1. A driver's airbag system, The airbag is positioned in the center of the steering wheel and, when deployed, extends beyond the rim of the steering wheel. The airbag body has a rear base fabric located on the driver's side and a front base fabric located on the opposite side from the driver relative to the rear base fabric. Multiple gas discharge holes are formed in the portion of the front base fabric that extends beyond the rim. The plurality of gas exhaust holes include a central hole located at a position corresponding to the center of the steering wheel, a first lateral hole positioned on one side in the vehicle width direction relative to the central hole and spaced apart from the central hole, and a second lateral hole positioned on the other side in the vehicle width direction relative to the central hole and spaced apart from the central hole. A driver's airbag device wherein the opening area of ​​the central hole is larger than the opening area of ​​the first lateral hole and the opening area of ​​the second lateral hole.

2. The driver's airbag device according to claim 1, wherein, when viewed directly from the rim, the central angles of the first lateral hole and the second lateral hole with respect to the center of the steering wheel are 60 degrees or more and 150 degrees or less, and the central hole is positioned on the bisector of the central angle.

3. The opening area of ​​the first side hole and the opening area of ​​the second side hole are the same. The driver's airbag device according to claim 1 or 2, wherein the ratio of the opening area of ​​the first lateral hole and the opening area of ​​the second lateral hole to the opening area of ​​the central hole is 0.5 or more and 0.9 or less.

Images