JP3022480U - Airbag for large diameter steering wheel - Google Patents

Abstract

(57) 【Abstract】 PROBLEM TO BE SOLVED: To suppress an increase in the capacity of an airbag, which is attached to a large-diameter steering wheel of a large vehicle such as a truck, due to an increase in the diameter of the steering wheel, to an airbag device. It is possible to prevent the increase in the weight of the vehicle and the deterioration of the operability of the steering wheel due to the increase in the weight, and to provide at low cost. SOLUTION: The gas generator 1 is provided at the approximate center of the back surface of a pair of front and back base cloths 14b and 14c having a circular peripheral portion 14d sewn 20.
5 has a gas generator mounting hole 14a to which 5 is mounted, and a part of the target position of the pair of front and back base fabrics centering on the gas generator mounting hole 14a is directly sewn 26a, 26b, 27a, 27.
When the bag is inflated and brought into close contact with the bag, the bag is inflated into a flat shape.

Description

[Detailed description of the device]

[0001]

[Technical field to which the device belongs]

 The present invention relates to a structure of an airbag for a driver seat mounted on a steering wheel of a vehicle having a large steering wheel such as a truck and a bus.

[0002]

[Prior art]

 The airbag device is one of the occupant protection devices that has rapidly spread in recent years, and is installed on the driver airbag device that is installed on the steering wheel of a passenger car and the instrument panel in front of the passenger seat. The airbag device for the passenger seat is a typical airbag device. In addition to these, there are some that have been partially put into practical use or are being put into practical use, such as side airbag devices for side collisions that are mounted inside doors and airbag devices for rear impact that are mounted on headrests. .

Among these, a conventional driver airbag device mounted on a steering wheel, which is closely related to the present invention, will be described with reference to the drawings. FIG. 5 is a cross-sectional view showing an example of a driver's seat airbag device mounted on a steering wheel of a conventional passenger car. The steering wheel 1 includes a hub portion 2, a spoke portion 4a, and an annular rim portion 3. The hub portion 2 is composed of two frame members 4 and 6, both of which are integrally fixed by a bolt (not shown). The first frame member 4 has a through hole 4d at the center of the hub portion 4e and a plurality of spoke portions 4a extending obliquely upward from the hub portion 4e. The second frame member 6 has a through hole 6c at the center of its hub portion 6b, and a plurality of retainer fixing portions 6a are provided at its outer edge portion so as to project upward. The hub portion 2 is fixed by a nut 8 to the tip portion 7a of the steering shaft 7 inserted into the through holes 4d and 6c of the two frame members 4 and 6. An annular core member 24 is fixed to the tip of the spoke portion 4a, and the outer peripheral portion of the core member is covered with a resin to form an annular rim portion 3. A resin is integrally covered from the annular rim portion 3 to the middle of each spoke portion 4a, and the tip end portions thereof are joint portions 10 and 11 to a bag cover 13, which will be described later. A core cover 5 is provided on the lower surface of the exposed portion of the spoke portion 4a from the hub portion 2 to the resin coating portion of the spoke portion 4a so as to cover the entire lower surface. A space above the inside, that is, a central space of the steering wheel 1 serves as a storage portion of the airbag device 12.

The airbag device 12 includes a bag cover 13, an airbag 14 folded and housed in the bag cover 13, and a short-cylindrical gas generator having a substantially quadrangular flange 17 projecting from its periphery. 15 and a plate-shaped retainer 16. The gas generator 15 has a through hole 16c opened at the center of the bottom of the retainer 16 and a gas formed at the center of the back surface of the airbag 14 so that the plurality of gas discharge holes 15a are located inside the airbag 14. It is inserted into the generator mounting hole 14a and is fixed to the four corners of the flange 17 of the gas generator 15 by bolting together with bolts 18. The airbag 14 is fixed to the flange 17 of the gas generator 15 around the mounting hole 14a by a plurality of rivets 23 that are closely spaced. Then, the retainer 16 has two mounting feet 16a protruding downward from the outer edge portion, which are fastened to the retainer fixing portion 6a of the second frame member 6 with a bolt 9 so as to be parallel to the hub portion 2 as shown in the figure. It is fixed to. In this way, the airbag device 12 is fixed to the steering wheel 1 via the retainer 16. Further, a bag cover mounting portion 16b bent upward is formed on the outer edge of the retainer 16, and the bag cover 13 is fixed by the rivets 19 by the mounting legs 13b.

The peripheral portion of the bag cover 13 is formed so as to come into contact with the joint portions 10 and 11 of the rim portion 3 with almost no gap, and the inside of the upper surface portion 13a is used when the airbag is deployed. A substantially H-shaped fracture groove 13c formed by a thin portion that is fractured by the inflation pressure of the airbag is formed.

When the airbag is deployed, the gas generator 15 is activated by a signal from a collision sensor (not shown), and a large amount of gas is ejected from the gas release hole 15a into the airbag 14 in an instant. The bag cover 13 is ruptured by the bulging pressure of the bag along the rupture groove 13c, and the airbag 14 bulges from the inside to protect the driver's face and chest from colliding with the steering wheel. Will be done.

[0007]

[Problems to be solved by the device]

 By the way, in the above-mentioned airbag device, the deployment shape of the airbag is designed to cover the front surface of the steering wheel 1 as shown in the schematic view of FIG. When used in combination with a seat belt, which is a design concept, the size of the gas generator 15 is at most about 30 to 40 liters, so that a small gas generator 15 having a diameter of about 7 to 8 cm is also used. There is a problem in applying this design concept as it is to large vehicles such as trucks and buses. In other words, the steering wheel of a large vehicle has a diameter that is considerably larger than that of a passenger vehicle from the viewpoint of operability, so a large air bag is required to cover the front surface of the steering wheel. Will be done. To meet this requirement, the gas generator itself must be large, and the weight of the airbag device must be increased accordingly, which deteriorates the operability of the steering wheel equipped with heavy objects. The problem of will occur.

On the other hand, according to the American design concept that the driver is protected only by the airbag even when the seat belt is not worn, the airbag capacity inevitably becomes large, but in this case, the airbag is Before the bulge is fully expanded, the bulge tip may collide with the occupant's face and give a strong impact, which may cause injury or death in some cases. As shown, a system in which a string-shaped tether 50 is provided inside the bag is adopted. That is, by sewn both ends of the tether 50 to the insides of the base fabrics 14b and 14c on the front surface and the back surface of the airbag 14, the airbag is expanded in a circle as shown by the dotted line in the figure. It is designed so as to prevent and spread flatly, but in this case, usually, two base fabrics are overlapped and the periphery is sewn to form a bag, and then the tether 50 is aired. Since it is provided inside the bag, it is necessary to use the gas generator mounting hole 14a of the bag to insert a sewing machine into the bag for sewing, which makes sewing work of this tether difficult and inefficient. As a result, there was a problem that the cost of the airbag becomes high.

The present invention has been made in view of the problems of the related art, and an object of the present invention is to provide an airbag mounted on a large-diameter steering wheel of a large vehicle such as a truck with a steering wheel of a steering wheel. The purpose is to minimize the increase in the capacity of the airbag due to the increase in diameter, prevent the increase in the weight of the airbag device and the deterioration of the operability of the steering wheel due to this, and provide the airbag at a low cost.

[0010]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the airbag according to the present invention has a pair of front and back base fabrics sewn with circular peripheral portions, and a gas generator mounting hole for mounting a gas generator in the approximate center of the back surface. Attached to a large-diameter steering wheel that expands into a flat shape when the bag is inflated by directly sewing and adhering part of the target position of the base cloth centering around the gas generator mounting hole It is in an airbag that will be. In particular, by directly sewn a part of the target positions on the four sides of the top, bottom, left and right, and making them adhere to each other, it is formed in the central inflating part that protects the head when the airbag is inflated and the outer ring, and the steering wheel rim part is formed. It is also possible to have two inflates, one in position and the other inflatable to protect the chest. Furthermore, by forming the sewing line at this target position into an arc shape that is concentric with the gas generator mounting hole, the force that acts on the sewing line during expansion can be dispersed, and it is possible to prevent stress from concentrating in one place. . Furthermore, by providing a vent hole outside the sewing line provided at the target position of the back surface fabric, the inflation time of the central portion of the airbag is maintained, and the inflation duration time is shortened due to the reduction in capacity. You can also cover this.

[0011]

[Embodiment of device]

 Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a plan view of an airbag according to the present invention as viewed from the back side. The airbag 14 has a base cloth 14b serving as the front surface and a base cloth 14c serving as the back surface, which are overlapped with each other. The portion 14d is joined by the sewing line 20 to form a bag body. The above-mentioned gas generator mounting hole 14a is formed in the central portion of the back surface thereof, and the reinforcing cloth 21 is sewn to the peripheral portion thereof. In addition, a small hole 25 for fixing by rivet to the flange of the above-mentioned gas generator is provided in the portion of the reinforcing cloth 21 in close proximity. Directly sew a part of the upper and lower target positions of the front and back base fabrics 14b and 14c around the gas generator mounting hole 14a to directly attach the front and back base fabrics 14b and 14c. Further, the front and back base cloths 14b and 14c are directly joined by the sewn portions 27a and 27b which are joined to each other and further sew a part of the symmetrical positions centering on the gas generator mounting hole 14a. Further, vent holes 28a, 28b, 28c, 28d for releasing the gas supplied from the gas generator to the outside are provided outside the sewing portions 26a, 26b, 27a, 27b at the target positions.

When the airbag is inflated, the airbag 14 is sewn at the target position as shown by the solid line in FIG. 2 as shown in the schematic view of the cross section of the airbag 27a (26a), 27b (26b). The central inflated portion 30 partitioned by the swelling then bulges out through the non-sewn portion, swelling the outer inflated portion 31 outside the sewn portion to create two swelling portions. As it is expanded as it is formed, as shown by the dotted line in the figure, it can be expanded more flatly than the expanded state without the sewing portion, and as a result, the airbag capacity is reduced. I understand things. Further, the surplus gas after the completion of deployment is discharged from the vent holes 28a to 28d to the outside of the airbag, but the position of the vent hole is the sewing lines 26a, 26b. 27a. Since it is formed on the outer side of 27b, the gas supplied from the gas generator 15 is supplied to the outer inflatable section 31 through the unsewn portion from the central inflatable section 30, so that the central inflatable section 30 is the last It will be possible to continue to maintain the inflated state, and the reduction of the air bag deployment maintenance time due to the smaller capacity and flatness of the airbag will be prevented, and the occupant's head will be reliably protected.

In the example of FIG. 2, the sewn portions at the target position are provided both vertically and horizontally, but it goes without saying that only one of them may be provided. In addition to the linear shape of the sewing line shown in FIG. 2, as shown in FIG. 3, the sewing line also has arcuate sewing portions 37a (36a), 37b which are concentric with the gas generator mounting hole and centered on the center of the airbag. (36b) is also acceptable. In particular, when the airbag has an arc shape, it can be deployed without exerting an unreasonable force on the front and back base fabrics when the airbag is inflated, and the central inflatable portion 30 and the outer inflatable portion 31 in FIG. 4 are concentrically formed. By inflating and positioning the outer inflating portion on the rim portion 3 of the steering wheel 1, there is an effect that the collision between the chest portion and the rim portion 3 of the steering wheel 1 is reliably mitigated. Furthermore, the number of sewn parts is not limited to one in the same target direction, but even if many sewn parts are used, the effect basically does not change. It is desirable to sew from the viewpoint of production cost. Further, the length of the sewing line may be several cm to ten and several cm, and the point is that the sewn part can be stably joined to the front and back base fabrics without tearing when the bag is inflated.

[0014]

[Effect of device]

 As described above, according to the airbag of the present invention, the following remarkable effects which cannot be obtained by the conventional airbag can be expected. (1) Since the target position centering on the gas generator mounting hole of the base fabric that constitutes the front and back surfaces is sewn directly and is in close contact, it is separated into the central inflated part and the peripheral side inflated part during deployment. The expanded shape is flat, and even if it is mounted on a large-diameter steering wheel, it is not necessary to increase the airbag capacity so much, so it is possible to use a small gas generator. As a result, the weight of the airbag device can be reduced and the operability of the steering wheel is not hindered. (2) By forming the sewing line at the target position in the shape of a concentric circular arc, the force acting on the sewing line when the airbag is deployed is relieved, and the center inflated portion and the side expansion are surely performed without breaking the sewn portion. Even if it is a small and small-capacity airbag, it is possible to reliably protect the head with the central inflating part and the chest with the outer inflating part. (3) By forming the vent hole in the side inflating part, the central inflating part can maintain the inflated state for a long time, so that the air bag inflating maintenance time by flattening the airbag and reducing the capacity can be reduced. It is possible to prevent the harmful effects of shortening. (4) Compared to the conventional method of flattening using a tether, in the present invention, it is possible to sew the sewn portion at the target position by overlapping the front and back base fabrics, so that the sewing machine can be sewn from the gas generator attachment hole It is much easier and cheaper to manufacture than the conventional method of putting the tether inside and attaching the tether.

[Brief description of drawings]

FIG. 1 is a schematic plan view of an airbag of the present invention.

FIG. 2 is a schematic cross-sectional view showing a deployed state of the airbag shown in FIG.

FIG. 3 is a schematic plan view showing another embodiment of the airbag of the present invention.

FIG. 4 is a schematic cross-sectional view showing a developed state of the airbag shown in FIG.

FIG. 5 is a schematic cross-sectional view of a conventional driver airbag device.

FIG. 6 is a schematic diagram showing a deployed state of a conventional driver airbag.

FIG. 7 is a schematic sectional view showing a deployed state of another conventional airbag.

[Explanation of symbols]

 1 Steering Wheel 3 Steering Wheel Rim 14 Airbag 14a Gas Generator Mounting Holes 14b, 14c Base Fabrics on Front and Back of Airbag 14d Circular Perimeter of Airbag 15 Gas Generator 20 Sewing of Circular Perimeter of Airbag 26a , 26b, 27a, 27b Sewing portion at the target position 28a to 28d Vent hole 30 Central inflating portion 31 Outer inflating portion

Claims (4)

[Scope of utility model registration request] 1. An airbag (14) mounted on a steering wheel (1) of a vehicle having a large-diameter steering wheel such as a truck, wherein a circular peripheral portion (14d) is sewn (20) on both sides. Base cloth (14
b, 14c) has a gas generator mounting hole (14a) for mounting a gas generator (15) substantially in the center of the back surface, and the gas generator mounting hole (14a) of the pair of front and back base fabrics is centered Directly sew part of the target position (26a, 26b, 27a, 2
An airbag to be mounted on a large-diameter steering wheel of a truck or the like, characterized in that the airbag is inflated into a flat shape when the bag is inflated. 2. A pair of front and back base cloths (14b, 14c)
By directly sewing and closely adhering a part of the upper and lower and left and right target positions centering on the gas generator mounting hole (14a), the central inflating portion (30) and the outer inflating portion (31) when the airbag is inflated. The airbag according to claim 1, wherein the airbag is formed. 3. The sewing line (26a, 26b, 27a, 27b) at the target position of the pair of front and back base fabrics is formed in an arc shape concentric with the gas generator mounting hole (14a), and when the airbag is inflated. The airbag according to claim 2, wherein the outer inflatable portion (31) is formed so as to be located on a rim portion (3) of a steering wheel. 4. The vent holes (28a to 28d) are provided in the back cloth (14c) outside the sewing lines (26a, 26b, 27a, 27b) at the target positions of the pair of front and back cloths.
The airbag according to claim 1, wherein the airbag is arranged.