JPH061032U - Vent hole structure of airbag bag - Google Patents

Abstract

(57) [Abstract] [Purpose] As the internal pressure of the airbag bag rises, the diameter of the gas vent opening can be increased, suppressing the amount of gas venting while the airbag bag is inflated. After the swelling of
Ensure a sufficient amount of gas escape to maintain a predetermined internal pressure. [Structure] The internal pressure of the airbag bag 22 rises, and as the internal pressure rises, a tensile load is applied to the sewing threads 62 and 64,
When the sewing threads 62 and 64 are cut, a tear load is applied to the bag wall 23 at the peripheral edge portion of the gas vent opening 42 by the cutting, and the bag wall 23 is developed as a tear piece to be unfolded to form the gas vent opening. The peripheral portion of 42 is moved and deformed, and the diameter of the gas vent opening 42 is enlarged. This increases the amount of degassing and suppresses the rise in internal pressure.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a vent hole structure for an airbag bag that is inflated by supplying gas when the vehicle is suddenly decelerated.

[0002]

[Prior art]

 The vehicle is provided with an airbag device, for example, on a steering wheel.

The airbag device is provided with an airbag bag body, and when gas is supplied to the inside of the airbag bag body during sudden deceleration of the vehicle, the airbag bag body bulges toward an occupant. As a result, the occupants are protected. It

A vent hole is provided in the airbag bag. The vent hole is a structure that is formed by a circular hole of a certain diameter that is opened on the surface of the airbag bag opposite to the occupant. According to this, after the airbag bag swells, the airbag bag is expanded. When an occupant comes into contact with the body and collides, the airbag bag smoothly absorbs the collision energy and catches the occupant, so the gas inside the airbag bag escapes from the vent hole to the outside and the internal pressure rises. Is suppressed.

[0005]

[Problems to be solved by the device]

 By the way, the volume of gas supplied to the airbag bag changes depending on the outside air temperature, and the weight of the occupant and the speed at which the occupant collides with the airbag bag differ depending on the occupant. In order for the hole to fully exhibit its function, it is desirable that the amount of degassing can be adjusted according to these changes. Further, in order to reach the predetermined shape and pressure of the airbag bag in a short time, it is preferable that gas escape from the vent hole is small during the expansion of the airbag bag.

Therefore, it is conceivable to use a special valve capable of controlling the amount of degassing in response to changes in internal pressure, while the conventional vent hole structure is a circular hole having a constant diameter. However, this complicates the structure and increases the manufacturing cost.

In consideration of the above facts, the present invention can increase the diameter of the gas vent opening as the internal pressure of the airbag bag rises, and suppress the amount of gas venting while the airbag bag is inflated. When the airbag bag is made to reach the specified shape and internal pressure in a short time, and after the airbag bag is inflated, a sufficient amount of gas is removed to maintain the specified internal pressure, and the occupant is received by the airbag bag. It is an object of the present invention to provide a vent hole structure for an airbag bag, which has a simple structure and realizes the energy absorption effect of the air bag body at a low cost.

[0008]

[Means for Solving the Problems]

 In order to solve the above-mentioned problems, the present invention provides a gas vent opening formed in an airbag bag body to which gas is supplied and swells when a vehicle is suddenly decelerated, and a surrounding wall of the airbag bag body. The sewn part is made into a peripheral part of the gas vent opening and is cut by the increase in the internal pressure of the airbag bag, so that the peripheral part of the gas vent opening is expanded in the expanding direction of the gas vent opening. The present invention proposes a vent hole structure for an airbag bag, which is provided with a sewing thread that allows movement deformation.

[0009]

[Action]

 According to the above configuration, when the vehicle is suddenly decelerated, gas is supplied into the airbag bag body, the airbag bag body bulges, and the occupant is protected.

At this time, when the internal pressure of the airbag bag rises and the sewing thread is cut off due to the increase in the internal pressure, this cutting causes the peripheral direction of the gas venting opening to expand toward the venting opening. Movement deformation to is allowed.

As a result, the diameter of the gas vent opening is increased, that is, the opening area of the gas vent opening is increased, the amount of gas vent is increased, and the rise in internal pressure is suppressed.

Then, when the airbag bag body is inflated, there is no internal pressure in the airbag bag body or the internal pressure is small, so that the sewing thread is not cut and the diameter of the vent opening increases. Without this, the amount of degassing is suppressed. As a result, the airbag bag can reach a predetermined shape and internal pressure in a short time.

After the airbag bag is inflated, the internal pressure rises and becomes high, so that the thread is cut. As a result, a sufficient amount of gas can be secured to maintain a predetermined internal pressure, and the energy absorbing effect when the occupant is received by the airbag bag is sufficiently exerted.

Further, this is realized with a simple structure and at low cost.

[0015]

【Example】

 A first embodiment of a vent hole structure for an airbag according to the present invention will be described in detail with reference to FIGS. 1 to 10.

FIG. 2 shows the airbag device 10. The airbag device 10 is provided on a base plate 16 supported by the hub portion 14 of the steering wheel 12, and is composed of a pad 18, an inflator 20, and an airbag bag body (hereinafter simply referred to as a bag body 22). There is.

The pad 18 is formed in a bowl shape, is arranged on the occupant side of the base plate 16 along the axis of the steering wheel 12, and is fixed so as to face the peripheral edge of the base plate 16. A thin portion 24 is formed on the surface of the pad 18 facing the occupant, and the pad 16 is ruptured by the swelling of a bag body 22 which will be described later, and the pad 16 is expanded in a double door structure. ing.

The inflator 20 has a substantially cylindrical shape, its axis is located along the axis of the steering 12, and approximately half the axial direction of the inflator 20 projects through the base plate 16 toward the occupant side. The flange 26 is integrally formed on the outer peripheral surface of the inflator 20, and is fixed to the base plate 16. Further, a plurality of gas holes 28 are formed on the peripheral surface of the occupant-side protruding portion of the inflator 20. A starter 30 is disposed inside the inflator 20, and a gas generating substance 32 is filled around the starter 30. When the vehicle suddenly decelerates, the starter 32 operates to generate a large amount of gas from the gas generating substance 32. Is generated, and the gas is supplied into the bag body 22 through the gas holes 28.

The bag body 22 is arranged in a folded state on the occupant side of the base plate 16 and is housed between the base plate and the pad. In addition, the bag body 22 is provided with a gas supply port 34, and the peripheral portion of the gas supply port 34 is attached to the base plate by a mounting ring 36 so that the occupant-side protruding portion of the inflator 20 is inserted into the gas supply port 34. It is fixed at 16. The bag body 22 is formed of a cloth material having excellent heat resistance and sealing properties.

Here, in the bag body 22, a circular gas vent opening 42 is formed around the gas supply port 34. At the portion where the gas vent opening 42 is formed, as shown in FIGS. 1, 3 and 4 (the outside of the bag 22 is indicated by an arrow OUT), the bag wall 23 of the bag 22 has a first wall The sewing thread 62 and the second sewing thread 64 are sewn. The first sewing thread 62 is concentric with the degassing opening 42 and is located on the circumference of a diameter of 15 mm, while the diameter or the diameter of the degassing opening 42 is 5 mm. . The second sewing thread 64 is concentric with the degassing opening 42 similarly to the first sewing thread 62, is located on the circumference of 30 mm in diameter, and is located radially outside the first sewing thread 62. is there.

A third sewing thread 66, which is made up of two sewing threads that are close to each other in the radial direction, is sewn on the outer side in the radial direction of the second sewing thread 64, and the circumference is concentric with the degassing opening 42. It is located on top. An annular reinforcing cloth 68 is provided on the inner surface of the bag wall 23 at the portion of the third sewing thread 66, and the reinforcing cloth 68 is sewn to the bag wall 23 by the third sewing thread 66. The reinforcing cloth 68 is concentric with the degassing opening 42 and has an inner diameter of 40 mm.

Further, the first sewing thread 62 has a thickness of 210 de, the second sewing thread 64 has a thickness of 630 de, and the third sewing thread 66 has a thickness of The length is 12 30 de, and the thickness of the sewing thread located on the outer side in the radial direction increases. According to this, in the first sewing thread 62 and the second sewing thread 64, the cutting of the sewing thread may occur, and the first sewing thread 62 is the second sewing thread. While the third sewing thread is cut with a tensile force smaller than that of the thread 64, the third sewing thread is made up of two adjacent sewing threads as described above, and is further provided with the reinforcing cloth 68 for sewing. It is especially reinforced to prevent thread breakage.

Next, the operation of this embodiment will be described based on the graph of FIG. 11 showing the relationship between the diameter of the gas vent opening 42 and the internal pressure of the bag body 22.

First, when the vehicle rapidly decelerates, the gas generated by the gas generating substance 32 is supplied into the bag body 22, and the bag body 22 swells to protect the occupant.

At this time, when the internal pressure of the bag body 22 rises, the outflow rate of the gas from the gas escape opening 42 increases with the increase of the internal pressure, and the bag wall 23 is pushed outward to remove the gas. At the peripheral edge of the opening 42, a tear load is applied to the bag wall 23. Then, the tear load radially tears the bag wall 23, and, for example, four partitioned tear pieces 70 are formed on the bag wall 23, and the tear pieces 70 are directed to the outside of the bag body 22. Expand so that it can be rolled up. The radial tear increases in length as the internal pressure of the bag body 22 increases, increasing the area of the tear piece 70 and making the diameter of the gas release opening 42 5 mm (D1 in FIG. 4). From the beginning to the area of the first sewing thread 62. In this state, the portion of the first sewing thread 62 becomes the peripheral portion of the gas vent opening 42, and the diameter of the gas vent opening 42 is approximately 15 mm (D2 in FIG. 6) (FIGS. 5 and 6).

Further, when the internal pressure of the bag body 22 rises and the first sewing thread 62 is cut by the tensile load, at the new peripheral portion of the degassing opening 42 having the diameter of D2 accordingly. The bag wall 23 is further torn so that the above-mentioned tear is extended to the outside in the radial direction, and the tear increases in length as the internal pressure of the bag 22 increases, and the diameter of the gas escape opening 42 increases. Is gradually expanded from D2 and reaches the position of the second sewing thread 64. In this state, the portion of the second sewing thread 64 becomes the peripheral portion of the new gas venting opening 42, and the diameter of the gas venting opening 42 becomes approximately 30 mm (D3 in FIG. 8) (FIG. 7 and FIG. (Figure 8).

When the internal pressure is further increased and the second sewing thread 64 is cut by the tensile load, the inner diameter of the second sewing thread 64 is further changed to a new peripheral portion of the degassing opening 42 having a diameter of D3. The bag wall 23 is torn so that the tear further extends to the outside in the radial direction, and the tear increases in length as the internal pressure of the bag body 22 increases, and the diameter of the gas release opening 42 is changed from D3 to D3. It is gradually expanded and reaches the portion of the third sewing thread 66 (the portion of the inner diameter of the reinforcing cloth 68). In this state, the portion of the second sewing thread 64 becomes the peripheral portion of the new gas vent opening 42, and the diameter of the gas vent opening 42 becomes approximately 40 mm (D4 in FIG. 8) (FIG. 7 and (Figure 8). After that, the reinforced third sewing thread 66 and the reinforcing cloth 68 prevent the third sewing thread 66 from being cut and the tearing of the bag wall 23 is prevented. Is the maximum caliber of.

In this way, when the first sewing thread 62 and the second sewing thread 64 are cut along with the increase in the internal pressure, the bag wall 23 is torn at the peripheral edge of the degassing opening 42, that is, , The displacement of the gas vent opening in the expanding direction is allowed, and the diameter of the gas vent opening 42 is expanded, that is, the opening area of the gas vent opening 42 is increased, the gas vent amount is increased, and the internal pressure The rise is suppressed.

Here, when the bag body 22 is in the process of swelling and there is no internal pressure or it is still low, there is no tear load on the bag body 22 at the peripheral edge of the gas escape opening 42, or Since the tear piece 70 is small and is not torn or has little tear, the diameter of the gas release opening 42 is small, gas escape is suppressed, and a predetermined shape and a predetermined internal pressure can be reached in a short time. .

After the bag body 22 bulges, the internal pressure increases, so that the first sewing thread 62 and the second sewing thread 64 are cut, and the bag wall 23 is torn at the peripheral edge of the degassing opening 42. As a result, the diameter of the gas escape opening 42 increases, the amount of gas escape increases, the prescribed internal pressure is maintained, and the energy absorption effect when the occupant is received by the airbag bag is fully exerted, and it can be used for a long time. Thus, the predetermined shape and the predetermined internal pressure are maintained.

In the above embodiment, the sewing thread to be cut is composed of the first sewing thread 62 and the second sewing thread 64. However, the number of threads is increased and the arrangement in the radial direction is dense. In this case, it is possible to perform more precise control when enlarging the diameter of the gas release opening 42 according to the increase in the internal pressure.

Further, this is realized with a simple structure and at low cost. Next, a second embodiment will be described based on FIGS. 12 and 13.

In this embodiment, when the bag wall 23 reaches the center of the gas release opening 42 and there is no internal pressure of the bag body 22, the gas release opening 42 is completely closed. Also, cross-shaped notches 71 are radially formed from the portion of the third sewing thread 66 (the portion of the inner diameter of the reinforcing cloth 66) to the center of the gas escape opening 42, and four existing pieces are previously formed. 72 is formed.

According to this configuration, as shown in the graph of FIG. 14 showing the relationship between the diameter of the gas vent opening 42 and the internal pressure of the bag body 22, as the internal pressure rises, first, the existing piece 72 is The tip of the first sewing thread 62 is expanded outward so that it is gradually wound around the rotation center of the first sewing thread 62, and the diameter of the degassing opening 42 is correspondingly increased to reach about 15 mm.

When the internal pressure is further increased, the first sewing thread 62 is cut by a tensile load, and at the same time, the existing piece 72 is expanded around the second sewing thread as a center of rotation to open the gas vent opening. The diameter of 42 is instantly expanded from about 15 mm to about 30 mm.

When the internal pressure is further increased, the third sewing thread is cut, and at the same time, the existing piece 72 is expanded with the portion of the third sewing thread 66 (the portion of the inner diameter of the reinforcing cloth 66) as the rotation center. Now, the diameter of the gas escape opening 42 is instantly increased from about 30 mm to about 40 mm. After this, as in the first embodiment, the existing piece 72 cannot further increase the expanded area, and the diameter of the gas escape opening 42 there becomes the maximum diameter.

In this way, the first sewing thread 62 and the second sewing thread 64 are cut, and the peripheral portion of the gas escape opening 42 is moved and deformed in the gas escape opening expanding direction.

The portion of the first sewing thread 62, the portion of the second sewing thread 64, and the portion of the third sewing thread 66 (the portion of the inner diameter of the reinforcing cloth 66) are the periphery of the gas vent opening 42. Although the developed state of the existing piece 72 when it becomes a part is similar to that of FIGS. 5 to 10 according to the first embodiment (except the shape of the tip of the existing piece 72), Since it is partitioned by the notch 71, there is no need to cut it and a precise caliber with high dimensional accuracy can be obtained. Further, only by cutting the first sewing thread 62 and the second sewing thread 64, the diameter of the gas escape opening 42 is instantly enlarged, and the enlargement of the diameter is controlled stepwise.

The other configurations and effects are similar to those of the first embodiment. Further, the present invention is not limited to the above embodiments, but various modifications can be made. For example, the position, shape, and quantity of the gas venting opening, and the shape and quantity of the deployable piece are not limited to those in the above embodiments, and the number, position, thickness, etc. of sewing threads are also limited. Not something.

[0040]

[Effect of device]

 With the vent hole structure of the airbag bag according to the present invention, the diameter of the gas vent opening can be increased as the internal pressure of the airbag bag rises. The amount of air is suppressed, the airbag bag reaches the specified shape and internal pressure in a short time, and after the airbag bag swells, the degassing amount that can maintain the specified internal pressure is ensured and the occupant is inflated. The energy absorption effect at the time of being received by the bag bag is sufficiently exerted, and this is realized with a simple structure and at low cost.

[Brief description of drawings]

FIG. 1 is a perspective view of a vent hole structure of an airbag bag according to a first embodiment of the present invention as viewed from the outside of the bag.

FIG. 2 is a cross-sectional view showing an airbag device to which the vent hole structure of the airbag bag of FIG. 1 is applied, taken along the axis of the steering wheel.

FIG. 3 is a view of the vent hole structure of the airbag bag according to the first embodiment as seen from the inside of the bag.

4 is an end view taken along line 4-4 of FIG.

FIG. 5 is a perspective view showing a state in FIG. 1 in which the inside of the bag is under a low pressure.

6 is an end view taken along line 6-6 of FIG.

FIG. 7 is a perspective view showing a state in FIG. 1 in which the inside of the bag is under a medium pressure.

8 is an end view taken along line 8-8 of FIG.

FIG. 9 is a perspective view showing a state in which the inside of the bag is under a high pressure in FIG. 1.

10 is an end view taken along line 10-10 of FIG.

FIG. 11 is a graph showing the relationship between the diameter of the gas escape opening and the internal pressure of the bag in the vent hole structure for the airbag according to the first embodiment.

FIG. 12 is a perspective view of a vent hole structure of an airbag bag according to a second embodiment as seen from the outside of the bag.

FIG. 13 is a view of a vent hole structure of an airbag bag according to a second embodiment as viewed from the inside of the bag.

FIG. 14 is a graph showing the relationship between the diameter of the gas vent opening and the internal pressure of the bag in the vent hole structure of the airbag according to the second embodiment.

[Explanation of symbols]

 22 Bag Body (Airbag Bag Body) 42 Gas Release Opening 62 First Sewing Thread (Sewing Thread) 64 Second Sewing Thread (Sewing Thread)

Claims (1)

[Scope of utility model registration request] 1. A degassing opening formed in an airbag bag body to which gas is supplied and swells when a vehicle is suddenly decelerated, and a bag wall of the airbag bag body is circumferentially sewn and sewed. A sewing thread that allows the attachment portion to be the peripheral portion of the gas vent opening and is cut by the increase in the internal pressure of the airbag bag, thereby allowing the peripheral portion of the gas vent opening to move and deform in the expansion direction of the gas vent opening. The vent hole structure of the air bag body, which is characterized in that