KR20110108106A - Process for preparing airbag cushion and sewing machine thereof - Google Patents

Abstract

The present invention relates to an airbag cushion and an airbag system including the same, in particular, comprising cutting at least one textile fabric, and sewing bonding the textile fabric, the sewing bonding process when sewing in the reverse direction The present invention relates to a method for manufacturing an airbag cushion and an airbag cushion sewing apparatus such that the tension of the upper thread sewing thread is 105% to 140% relative to the tension of the upper thread sewing thread when sewing in the forward direction.
According to the present invention, by adjusting the tension of the sewing thread to the optimum range, it is excellent in work stability and airbag deployment performance, and with excellent form stability and air blocking effect, thereby minimizing the impact on passengers to protect the occupants safely. Airbag cushions can be made.

Description

Method for manufacturing airbag cushion and sewing device {PROCESS FOR PREPARING AIRBAG CUSHION AND SEWING MACHINE THEREOF}

The present invention relates to a method for manufacturing an airbag cushion and a sewing device for an airbag cushion, and more particularly, a manufacturing method capable of manufacturing an airbag cushion having excellent work stability and airbag deployment performance by adjusting the tension of the sewing thread to an optimal range. It relates to a sewing apparatus that can be used in such a process.

In general, an air bag detects a collision shock applied to a vehicle at a speed of about 40 km / h or more at a speed of about 40 km / h, and then explodes a gunpowder to gas into the airbag cushion. By means of supplying and inflating, it refers to a device for protecting the driver and passengers, the structure of a general airbag cushion system is as shown in FIG.

As shown in FIG. 1, a general airbag cushion system includes an inflator 121 that generates gas by ignition of the primer 122, and an airbag cushion 124 that is expanded and deployed toward the driver of the driver's seat by the generated gas. Consists of the airbag cushion module 100 is mounted to the steering wheel 101, the impact sensor 130 for generating a shock signal in the collision, and the electron to ignite the primer 122 of the inflator 121 according to the shock signal It is configured to include a control module (Electronic Control Module) (110). The airbag cushion system configured as described above detects an impact in the impact sensor 130 and transmits a signal to the electronic control module 110 when the vehicle collides at the front. At this time, the electronic control module 110 that recognizes this ignites the primer 122, and burns the gas generating agent inside the inflator 121. The gas generator thus burned inflates the airbag cushion 124 through rapid gas generation. The inflated airbag cushion 124 partially absorbs the impact load caused by the collision while contacting the front upper body of the driver, and the inflated airbag cushion 124 as the head and chest of the driver move forward by inertia; In the event of a collision, the gas of the airbag cushion 124 is rapidly discharged to the discharge hole formed in the airbag cushion 124 and is cushioning the front part of the driver. Therefore, the secondary injury can be reduced by effectively buffering the impact force transmitted to the driver during frontal collision.

As described above, the airbag cushion used in the vehicle is manufactured in a predetermined form, and then mounted in a handle or an automobile side window or side structure of the vehicle in a folded state to minimize its volume. At this time, while fixing to the vehicle body using a tab portion of the airbag cushion and the like, while maintaining the folded state, the airbag cushion is inflated and deployed when the inflator 121 is operated.

In this case, typically the sewing type airbag includes a fabric and a sewing portion for bonding the fabric. That is, since the part of the air is mainly discharged during the deployment of the airbag is a sewing portion, the physical properties such as the sewing strength and elongation of the sewing portion is important. In particular, in order to exhibit excellent inflation performance and deployment performance when deploying airbags due to rapid gas generation, etc., the bonding performance for each part of the airbag cushion should be effectively maintained.

However, the sewing type airbag to which the conventional automatic sewing machine is applied is not sufficient to provide effective inflation performance and deployment performance in airbag operation when the physical properties such as sewing strength and elongation of the sewing unit. Such a problem is limited only by the material change of the sewing material applied to the sewing part, and there is an urgent need for technology development that can optimize the properties of the sewing part without changing the material.

Therefore, there is a need for research on the manufacturing process of the airbag cushion and the development of a sewing device that can form a sewing unit having excellent mechanical properties and air blocking effect so as to exhibit excellent inflation performance and deployment performance during airbag deployment.

The present invention is to provide a method for manufacturing an airbag cushion having excellent air barrier properties and pressure resistance maintaining performance by adjusting the tension of the sewing thread to the optimum range.

It is another object of the present invention to provide an airbag cushion sewing apparatus capable of forming a sewing portion of an airbag cushion having excellent air barrier property and pressure resistance maintenance performance.

The present invention includes the steps of cutting at least one fabric fabric, and sewing the fabric fabric, the sewing bonding process is the tension of the upper thread sewing thread sewing in the forward direction when sewing in the reverse direction to the tension of the upper thread sewing thread Compared to 105% to 140% to provide a method for producing an airbag cushion.

The present invention is also provided with a needle for sewing and joining the fabric fabric, the main thread regulator for giving tension to the upper thread sewing thread and the sub thread adjuster for giving a preliminary tension to the upper thread sewing thread supplied to the main thread controller, It is provided in the course of the upper thread sewing thread from the needle to the needle, and provides a sewing device of the airbag cushion further comprising a control means for finely adjusting the preliminary tension according to the thread adjuster.

Hereinafter, a method of manufacturing an airbag cushion according to a specific embodiment of the present invention and a sewing device of an airbag cushion that can be used in such a process will be described in more detail. However, this is presented as an example of the invention, whereby the scope of the invention is not limited, it is apparent to those skilled in the art that various modifications to the embodiments are possible within the scope of the invention.

In addition, unless otherwise indicated throughout the specification, "including" or "containing" refers to the inclusion of any component (or component) without particular limitation and refers to the addition of another component (or component). It cannot be interpreted as excluding.

The present invention by applying the optimized sewing conditions and sewing method for the sewing unit for bonding when manufacturing the airbag cushion, improve the sewing strength and elongation of the sewing unit to exhibit excellent deployment performance when inflating the airbag and maintain excellent pressure resistance performance It can be secured.

Airbag cushions are generally made by sewing and bonding the fabric to define the portion that inflates when the inflator bursts. More specifically, in manufacturing the airbag cushion by sewing the fabric for the airbag by the automated method by a general method, as shown in Figure 2, the lower thread 201 and the upper thread 202 on the fabric fabric 200 is It is used, the sewing proceeds while the upper thread 202 is supplied from the sewing device to the lower thread 201 in a predetermined direction. At this time, while the fabric fabric 200 is fixed, the needle of the sewing device moves while changing the direction and the sewing proceeds while the upper thread 202 is supplied in the same direction as the needle.

Therefore, even when sewing the fabric forming one airbag cushion, the supply direction of the upper thread to the fabric may be changed, the supply direction of the upper thread 202 to the lower thread 201 may also be changed (see FIG. 2).

Depending on the feeding direction of this upper thread 102, "forward" or "reverse" may be defined. Of these, the "forward direction", as shown in Figures 2, 3, 5, the supply direction of the upper thread 202 and the fabric of the upper thread 202 that the upper thread 202 can sew without twisting with respect to the lower thread 201 Can be defined as referring to the sewing direction (see FIGS. 2, 3, and 5), and “reverse direction” means that the upper thread 202 is twisted against the lower thread 201 as shown in FIGS. This may be defined as referring to the supply direction of the upper thread 202 and the sewing direction of the fabric to which sewing is performed (see FIGS. 2, 4, and 6).

By the way, this sewing direction, ie, "forward" or "reverse direction" is different whether or not the upper thread 102 twisted to the lower thread 100, between the sewing thread sewn in these "forward" and "reverse direction, respectively, upper thread sewing thread The required length and the like will vary, and the joining performance of the sewing portion will be varied.

As a result of the experiments of the present inventors, it has been found that by adjusting the tension of the upper thread sewing thread to the optimum range in the forward and reverse sewing processes, the physical properties of the sewing portion can be optimized to greatly improve the air barrier property and the pressure resistance performance of the airbag cushion.

Accordingly, the present invention prevents the mechanical property deterioration when sewing in the reverse direction, so that both the first sewing portion sewn in the forward direction and the second sewing portion sewn in the reverse direction ensure uniform mechanical properties and at the same time the airbag cushion Improved properties can also be achieved in the development performance of.

According to one embodiment of the present invention, there is provided a method of manufacturing an airbag cushion to optimize the tension of the upper thread sewing thread to a predetermined range. The manufacturing method of such an airbag cushion includes cutting at least one fabric fabric, and sewing the fabric fabric, wherein the sewing bonding process is the upper thread when the tension of the upper thread sewing thread sewing in the reverse direction Compared to the tension of the sewing thread can be adjusted to apply 105% to 140%, preferably 107% to 135%, more preferably 110% to 130%.

At this time, when the tension range of the sewing thread when sewing in the reverse direction is less than 105% compared to the tension when sewing in the forward direction, the mechanical properties of the second sewing portion sewn in the reverse direction is significantly lowered, air barrier properties and pressure resistance performance Degradation and thus deployment performance may be significantly reduced. In addition, when sewing in the reverse direction when the tension range of the sewing thread is applied in excess of 140% of the tension when sewing in the forward direction, the yarn is cut or trimmed during the sewing process, the entire process is not performed smoothly or the strength of the sewing portion is too By being strong, the fabric may be damaged or the deployment point or shape of the airbag may be abnormally deployed when the airbag is deployed.

In addition, the sewing bonding process may be performed so that the length of the upper thread sewing thread per unit length of the fabric is less than 15% between the first sewing portion sewing in the forward direction and the second sewing portion sewing in the reverse direction. That is, the sewing bonding process is the deviation of the sewing thread required length (L ₁ ) of the first sewing portion sewn in the forward direction per unit length of the airbag cushion fabric and the sewing thread required length (L ₂ ) of the second sewing portion sewn in the reverse direction (△ L ) May be 15% or less, or 1% to 15%, preferably 12% or less, or 1.5% to 12%, more preferably 10% or less, or 2% to 10%. In particular, the required length deviation ΔL of the sewing thread in the first sewing part and the second sewing part may be represented by the following formula (1).

[Calculation 1]

In the formula, L ₁ is the sewing thread required length per unit length of the fabric in the first sewing portion sewn in the forward direction, L ₂ is the sewing thread required per unit length of the fabric in the first sewing portion sewn in the forward direction.

Here, the sewing thread required length deviation (ΔL) between the first sewing portion and the second sewing portion is the first sewing sewing in a forward direction from the sewing thread required length (L ₂ ) per unit length of the fabric in the second sewing portion sewn in the reverse direction It can be expressed as a percentage value in the sewn portion of the absolute value of the difference value between the bongjesa required length (L ₁₎ per unit length of the fabric in the first sewing bongjesa required length (L ₁₎ portion.

When the sewing thread required length deviation (ΔL) between the first sewing part and the second sewing part sewn in the forward and reverse directions exceeds 15%, the second sewing sewn in the reverse direction compared to the first sewing part sewn in the forward direction The mechanical properties of the sewing unit are remarkably inferior, and the air barrier property and the pressure resistance performance of the airbag cushion may be greatly reduced according to the difference in physical properties between the first sewing unit and the second sewing unit.

In addition, in the sewing bonding process in the forward and reverse sewing by adjusting the tension of the upper thread in the optimum range, the kind of sewing thread used in each of the first sewing portion sewn in the forward direction and the second sewing portion sewn in the reverse direction, When the same thickness, sewing method, number of stitches, etc. are applied in the same way, a more preferable effect can be obtained.

As described above, according to the present invention, by adjusting the tension of the upper thread sewing thread in the sewing direction to the optimum range, it is possible to optimize the physical properties of the airbag cushion. In particular, according to the present invention by optimizing the tension of the upper thread sewing thread when sewing in the reverse direction 105% to 140% compared to the tension of the upper thread sewing thread when sewing in the forward direction, ensuring excellent mechanical properties to the same degree as the forward sewing portion in the reverse sewing In addition, it is possible to obtain improved physical properties in terms of excellent air barrier performance, airtightness, and deployment performance.

In the sewing joining process, a sewing thread including at least one selected from the group consisting of a nylon-based yarn, a polyester-based yarn, a polyolefin-based yarn, and an aramid-based yarn may be used, and nylon 66 and nylon as a sewing thread in terms of heat resistance and shrinkage. It is preferable to use yarns such as 46 and Kevlar (aramid yarn), and most preferably nylon 66 can be used.

The thickness of the sewing thread, that is, the total fineness may be used having a 210 to 1,260 denier, preferably 840 to 1,260 denier, the sewing thread thickness is preferably 210 denier or more in terms of strength, the sewing thread thickness in terms of resistance (elasticity) It is preferable that it is 1,260 denier or less. The denier is a unit representing the thickness of a yarn or fiber, and is 1 denier when the length of 9,000 m is 1 g.

In addition, the sewing thread can be used with a tensile strength of 58 N or more, preferably 58 N to 110 N measured by the method of the American Society for Testing and Materials ASTM D 204-97 standard, the preferred range is 89 N for 1,260 denier To 110 N, 840 denier can be used from 58 N to 80 N. If the tensile strength of the sewing thread is less than the above range, the strength of the sewing part is too weak, so that the sewing part may be torn off during manufacture or deployment of the air bag. The development time point or shape of may be abnormally developed.

The sewing bonding process of the present invention can be applied to select an effective sewing method according to the use of each site, one or more sewing methods can be applied from single lock, double lock, single chain, double chain.

In addition, the sewing bonding process may be applied by adjusting the number of stitches in the optimum range according to the use of each site or according to the sewing method, preferably 20 to 80 ea / 100mm, more preferably 25 to 75 ea / 100mm , More preferably 30 to 70 ea / 10mm to adjust the number of stitches to sewing can be bonded. At this time, if the number of stitches is less than 20 ea / 100mm, the strength of the sewing part is too weak, so that the sewing part may be torn during manufacture or development, and if the number of stitches exceeds 80 ea / 100mm, the strength of the sewing part is too strong and When the airbag is damaged or the airbag is deployed, the time or shape of the airbag may be abnormally deployed.

The sewing portion is sewn and bonded by optimizing the tension of the sewing thread according to the present invention 100 ~ 400 kgf / inch, preferably 130 to 350 kgf / inch, most preferably measured by the method of ASTM D 1683 Preferably from 150 to 300 kgf / inch. In addition, the elongation measured by the method of the American Society for Testing and Materials ASTM D 1683 may be 15% to 80%, preferably 20% to 70%, and most preferably 25% to 60%. The sewing portion of the airbag cushion manufactured in accordance with the present invention is preferably to maintain the strength and elongation in the above range in terms of securing the strength of the sewing portion to the optimum range and to achieve an effective pressure-resistant maintenance performance.

In addition, in the case of manufacturing the airbag cushion according to the present invention, when the instantaneous pressure of 25 bar is injected into the airbag cushion and the airbag internal pressure is measured, the maximum pressure at the initial airbag inflation (at start) is preferably 100 KPa or more, more Preferably 105 KPa, more preferably 110 KPa or more. This excellent pressure resistance performance can exhibit excellent performance as a safety system (safety system) when the airbag cushion of the present invention is mounted on a vehicle airbag system.

 In a preferred embodiment of the present invention, the internal pressure of the airbag cushion can be measured using the apparatus as shown in FIG. After the nitrogen gas is charged to the primary high-compression tank at high pressure in the measuring device, the first solenoid valve is opened by a computer to adjust the secondary tank to be filled with nitrogen gas up to 25 bar. When the secondary tank is filled in this way, the first solenoid valve is closed, and the second solenoid valve is opened by the computer, and the compressed nitrogen gas charged to the secondary tank at a pressure of 25 bar is kept at atmospheric pressure. Exit the airbag cushion and deploy the airbag cushion. At this time, the initial maximum pressure inside the airbag cushion is measured by the pressure sensor and recorded by the computer.

Therefore, the airbag cushion manufactured as described above preferably has an initial maximum pressure of 100 KPa or more when the injection pressure is applied at an instantaneous pressure of 25 bar, the sewing strength of the sewing portion is 100 kgf / inch or more, Elongation can be below 80%.

On the other hand, as the fabric fabric that can be used in the manufacture of the airbag cushion according to the present invention can be used both fabric or non-woven fabric known in the art for the manufacture of airbag cushion, it is not limited to that kind. For example, the fabric or nonwoven fabric may be a fabric or nonwoven fabric including a fiber selected from the group consisting of nylon fibers, polyester fibers, polyolefin fibers, and aramid fibers. For example, a textile fabric including nylon 66, polyethylene terephthalate (PET), polypropylene (PP), or the like can be used. The type of the woven fabric or the nonwoven fabric of the woven fabric used in the present invention is also not particularly limited, but nylon 66 or the like is preferably used in consideration of the strength of the sewing portion.

The textile fabric may be processed into a conventional air bag cushion fabric through a conventional weaving method, refining and heat setting, and then, if necessary, may be processed through an additional process such as silicone rubber coating. The airbag cushion fabric coated as described above is manufactured into a predetermined airbag cushion through a cutting and sewing process as described above. At this time, the airbag cushion is not limited to a special form and may be manufactured in a general form.

In particular, the textile fabric may preferably further comprise a rubber component coating layer coated or laminated on one surface or both surfaces. The rubber component may include at least one selected from the group consisting of powder type silicone, liquid type silicone, polyurethane, chloroprene, neoprene rubber, and emulsion type silicone resin, and the coating rubber component. The type of is not limited only to the above-mentioned materials. However, silicone coating is preferable in terms of environmentally friendly and mechanical properties.

At this time, the coating amount per unit area of the rubber component coating layer may be used to 20 to 200 g / m ² , preferably 20 to 100 g / m ² . Particularly, in the case of manufacturing an OPW (One Piece Woven) type side curtain type airbag, the coating amount is preferably 30 to 95 g / m ² , and in the case of plain weave type fabric, the coating amount is 20 to 50 g / m ² level is preferred.

In addition, in the airbag cushion manufacturing method of the present invention, the sewing bonding process may be used any device known to be available for the sewing-type airbag, can be operated using an industrial sewing machine, such as moving the head in terms of process efficiency. . In particular, when sewing in the forward and reverse directions, a separate sewing thread tension adjusting means may be added to adjust the sewing thread tension to the optimum range, and the sewing thread tension adjusting means may be manually operated or digitally controlled through computer programming. contoller).

On the other hand, according to another embodiment of the present invention, there is provided a sewing apparatus of an airbag cushion that can be adjusted to optimize the tension of the sewing thread in a predetermined range. The sewing device of the airbag cushion is provided with a needle for sewing and bonding the fabric fabric, the main thread adjuster for giving tension to the upper thread sewing thread and the sub thread adjuster for giving a preliminary tension to the upper thread sewing thread supplied to the main thread adjusting machine, It may be provided in the middle of the upper thread sewing thread path from the thread supply source to the needle, and further comprising a control means for fine-adjusting the preliminary tension according to the sub-thread adjuster.

In the sewing device of the airbag cushion, the preliminary tension according to the thread adjuster is 105% to 140%, preferably 107% to 135%, more preferably than the tension of the upper thread sewing thread when sewing in the forward direction when sewing in the reverse direction Preferably it can be adjusted to apply to 110% to 130%. In addition, the tension of the upper thread sewing thread in the sewing device may be applied so that the length of the upper thread sewing thread per unit length of the fabric is less than 15% between the first sewing portion sewing in the forward direction and the second sewing portion sewing in the reverse direction.

In a preferred embodiment, the air bag cushion sewing device 800, as shown in Figure 8, has a needle 801 for sewing bonded fabric fabric, the main thread for providing tension to the upper thread sewing thread 802 A thread adjusting device 803 and a sub thread adjusting device 804 for providing preliminary tension to the upper thread sewing thread supplied to the main thread adjusting machine are provided in the middle of the path of the upper thread sewing thread 802 from the thread supply source to the needle 801. It may be further to include an adjusting means 805 for finely adjusting the preliminary tension in accordance with the thread adjuster (804).

The main thread adjuster 803 is provided with a means for stably supplying the upper thread sewing thread to the needle 801 and maintaining a constant tension. Tensioning by the main thread controller 803 can be realized by giving a manually fixed value according to the type of sewing thread, the number of stitches, the type of fabric.

The sub thread adjuster 804 is provided with a preliminary tension to the main thread adjuster 803, a means for finely adjusting the tension adjusted by the main thread adjuster 803. Tensioning by the failure controller 804 can be realized by giving a fine value manually fixed according to the type of sewing thread, the number of stitches, the type of fabric.

In addition, the adjusting means 805 for finely adjusting the preliminary tension according to the thread adjuster 804 finely adjusts the tension changed in accordance with the sewing direction means for automatically adjusting the tension difference according to the sewing direction, etc. Equipped. Tensioning by the preliminary tension fine adjusting means 805 may adjust tensioning by automatically adjusting the upper thread sewing thread according to the sewing direction.

The preliminary tension fine adjustment means 805 may be operated manually or by a digital controller through computer programming. In particular, the preliminary tension fine control means 805, as shown in Figure 8, so as to sufficiently lower the tension to the upper thread sewing thread when sewing in the forward direction (dotted line), when sewing in the reverse direction to the upper thread sewing thread in the optimum range Can be operated to give (solid line).

As described above, the airbag cushion sewing device of the present invention is further equipped with a preliminary tension fine adjusting means together with the main thread adjuster and the sub thread adjuster, so as not to impart a fixed value of tension to the sub thread adjuster, but finely continuous the degree of tension application. By adjusting, the automatic adjustment can be made.

On the other hand, according to another embodiment of the present invention, there is provided an airbag cushion manufactured according to the above-described method. In particular, the airbag cushion may be manufactured by optimizing the tension of the upper thread sewing thread in a predetermined range, the airbag cushion may be processed in a conventional form and the like well known to those skilled in the art.

The airbag cushion has a deviation (△ L) of a sewing thread required length (L ₁ ) of the first sewing part sewing in the forward direction per unit length of the airbag cushion fabric and a sewing thread required length (L ₂ ) of the second sewing part sewing in the reverse direction. It may be up to% or from 1% to 15%, preferably up to 12% or from 1.5% to 12%, more preferably up to 10% or from 2% to 10%.

In addition, according to another embodiment of the present invention, there is provided an airbag system comprising an airbag cushion manufactured according to the method described above. In particular, the airbag system may include an airbag cushion which is manufactured by optimizing the tension range of the sewing thread to a predetermined range, and the airbag system may include a conventional device well known to those skilled in the art.

The airbag can be broadly classified into a front airbag (front type airbag) and a side airbag. The front airbags may be of the kind of driving, a passenger seat, a knee, ankle, and the like, and the side airbag includes a side airbag and a curtain airbag of an automobile. Accordingly, the airbag may be a front airbag, a side airbag or a curtain airbag.

In the present invention, matters other than those described above can be added or subtracted as required, and therefore, the present invention is not particularly limited thereto.

According to the present invention, there is provided a method of manufacturing an airbag cushion having excellent work stability and airbag deployment performance of a sewing unit, and an airbag cushion sewing device that can be used for the same.

In particular, the present invention is to improve the sewing strength and elongation of the sewing portion to exhibit excellent deployment performance when inflating the air bag by optimizing the tension of the sewing thread in a predetermined range, as well as to manufacture an air bag cushion having excellent pressure resistance performance, The manufactured airbag cushion provides excellent shape stability and air blocking effect, and minimizes the impact on the passengers, thereby protecting the occupants safely.

Therefore, the airbag cushion manufactured according to the present invention can be very preferably used for a vehicle airbag system or the like.

1 shows a typical airbag system.
Figure 2 is a schematic diagram showing a second sewing portion sewn in the reverse direction and the first sewing portion sewn in the forward direction in the airbag cushion according to an embodiment of the present invention.
Figure 3 is a schematic diagram showing the structure of the upper thread and the lower thread of the first sewing portion sewn in the forward direction in the airbag cushion according to an embodiment of the present invention.
Figure 4 is a schematic diagram showing the structure of the upper thread and the lower thread of the first sewing part sewn in the reverse direction in the airbag cushion according to an embodiment of the present invention.
Figure 5 is a photograph showing the structure of the upper thread and the lower thread of the first sewing part sewn in the forward direction in the airbag cushion according to an embodiment of the present invention.
Figure 6 is a photograph showing the structure of the upper thread and the lower thread of the second sewing part sewn in the reverse direction in the airbag cushion according to an embodiment of the present invention.
Figure 7 is a schematic diagram showing the internal pressure measurement apparatus of the airbag cushion according to an embodiment of the present invention.
Figure 8 is a schematic diagram showing a sewing device of an airbag cushion according to an embodiment of the present invention.
Figure 9 is a graph showing the internal pressure measurement results of the airbag cushion including a sewing part according to Example 1 of the present invention.
10 is a graph showing the internal pressure measurement results of the airbag cushion including a sewing part according to Comparative Example 1 of the present invention.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the scope of the present invention is not limited to the following examples.

Example  1-2

After weaving the fabric under the conditions shown in Table 1 below, the airbag is coated with a non-coating fabric or a coating fabric applied with a knife over ro1l coating method, which has undergone a refining and tentering process. It was used as a cushion fabric fabric. The fabric was cut using a laser cutting machine, and a sewing bonding process of the fabric was performed using a sewing apparatus as shown in FIG. 8. The sewing bonding process was applied under sewing conditions as shown in Table 1 below to prepare an airbag cushion.

At this time, the type of sewing thread, sewing method, number of stitches, tension, type of fabric and weaving form, coating components and coating amount are as shown in Table 1 below. Here, the tensile strength of the sewing thread is a value measured according to the American Society for Testing and Materials Standard ASTM D 206-97, and the required length of the sewing thread upper thread in the first sewing part sewing in the forward direction and the second sewing part sewing in the reverse direction is The required length of the upper thread per unit length (10 cm) is shown. In addition, the types of sewing thread used in the first sewing portion and the second sewing portion, the sewing method, the number of stitches and the like were applied in the same manner. The rest of the conditions were in accordance with conventional conditions for the manufacture of airbag cushions.

Comparative example  1-2

The airbag cushions of Comparative Examples 1 and 2 were prepared in the same manner as in Examples 1 and 2, except that the conditions were changed as shown in Table 1, and the physical properties thereof were shown in Table 1 below.

Physical properties of the airbag cushions prepared according to Examples 1 and 2 and Comparative Examples 1 and 2 were measured by the following methods, and the measured physical properties are summarized in Table 1 below.

a) bark strength and elongation

The bark strength and elongation of each of the first sewing part sewing in the forward direction and the second sewing part sewing in the reverse direction in the airbag cushion were measured.

First, the specimen of the airbag cushion was fixed to the lower clamp of the measuring device according to the ASTM D 1683 method of the American Society for Testing and Materials, and the bark strength and elongation at the time of breaking the airbag cushion specimen were measured while moving the upper clamp upward.

b) Internal pressure measurement when inflating the airbag cushion

As shown in Figure 7, after the air bag cushion is deployed by instant injection of 25 bar nitrogen gas into the air (Air) to observe the change in the internal pressure of the air bag hourly, the maximum internal pressure during the initial air bag cushion inflation Table 1 Shown in In particular, since this operation is preferably controlled electronically to minimize the error, the electronic control device is used here for the injection and blocking of the air.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Sewing thread type Nylon 66 Nylon 66 Nylon 66 Nylon 66 Sewing thread tensile strength (N) 100.9 107.8 100.9 107.8 Sewing thread Total Fineness (de) 1,260 1,260 1,260 1,260 Sewing Single rock Single rock Single rock Single rock Sewing stitch number (ea / 100mm) 65 65 65 65 Forward contrast
Reverse Sewing Thread Tension (%) 110 125 100 145 Type of fabric Nylon 66 Nylon 66 Nylon 66 Nylon 66 Total fineness of fabric (de) 420 420 420 420 Weaving density of the fabric 49X49 49X49 49X49 49X49 Weaving type of fabric (plain weave / OPW) Plain weave Plain weave Plain weave Plain weave Rubber ingredient silicon silicon silicon silicon Rubber coating amount (g / m ² ) 25 25 25 25 First sewing part upper thread length (mm) 329 324 330 Not sewing Second sewing section upper thread length (mm) 344 335 390 Non-sewn 1st sewing part / 2nd sewing part
Upper thread deviation (%) 4.6 3.4 16.7 Not sewing 1st Sewing Bar Thread Strength (kgf) 233 231 238 Not sewing Second sewing part sewing strength (kgf) 219 221 170 Not sewing First sewing part elongation (%) 48 47 51 Not sewing Second sewing part elongation (%) 52 50 87 Not sewing Maximum Internal Pressure at Expansion (kPa) 125 126 97 Non-sewn

In addition, graphs of the measurement results of the internal pressure during inflation of the airbag cushion of Example 1 and Comparative Example 1 are shown in FIGS. 9 and 10, respectively.

As shown in Table 1, in the case of Examples 1 to 2 in which the sewing thread's tension was optimized in the forward and reverse directions, the sewing portion of the airbag cushion ensures uniform bonding performance as a whole, and thus the initial airbag with excellent bar neck strength and elongation. It can be seen that the maximum pressure at the time of cushion inflation is 125 to 126 kPa, which has excellent pressure resistance performance. In particular, the airbag cushion prepared according to Examples 1 to 2 exhibits a degree in which the sewing strength and elongation of the reverse sewing sewing portion are similar to the sewing strength and elongation of the sewing sewing portion forward, and thus, the airbag cushion has uniform physical properties as a whole. You can check it.

On the other hand, in the case of Comparative Example 1 in which the same forward and reverse sewing thread tension is applied in the same manner as before, the bark strength and elongation are remarkably decreased, and thus it is not possible to provide a uniform and excellent sewing bonding performance as a whole. In particular, in the airbag cushion prepared according to Comparative Example 1, the elongation of the second sewing portion sewn in the reverse direction reaches about 87%, and the elongation of the second sewing portion is about 170% of the elongation of the first sewing portion sewn in the forward direction. It can be seen that exceeds. Accordingly, the sewing strength of the second sewing portion sewn in the reverse direction in the airbag cushion of Comparative Example 1 is only about 71% compared to the sewing strength of the first sewing portion sewn in the forward direction. Significantly lowered to 97 kPa, it can be seen that the overall physical properties and deployment of the airbag cushion is poor.

In addition, in the case of Comparative Example 2 in which the tension of the upper thread sewing thread is sewn in the reverse direction when sewing in the forward direction, 145% of the tension of the upper thread sewing thread is applied, the sewing thread is excessively imparted and the sewing thread is cut or the sewing device is unreasonable. Was not possible.

Therefore, as described above, by adjusting the tension of the sewing thread to the optimum range, it can be seen that the airbag cushion having excellent work stability and airbag deployment performance, excellent shape stability and air blocking effect can be produced have.

Claims (8)

Cutting at least one textile fabric, and
Sewing the fabric fabric;
The sewing bonding process is a method of manufacturing an airbag cushion so that the tension of the upper thread sewing thread when sewing in the reverse direction is 105% to 140% compared to the tension of the upper thread sewing thread when sewing in the forward direction. The method of claim 1,
The sewing bonding process is a method of manufacturing an airbag cushion that is applied to at least one sewing method selected from the group consisting of single lock, double lock, single chain, and double chain. The method of claim 1,
The sewing bonding process is a method of manufacturing an airbag cushion that is applied so that the stitch number is 20 to 80 ea / 100mm. The method of claim 1,
A method of manufacturing an airbag cushion having a sewing strength of 100 to 400 kgf / inch, measured by the method of the American Society for Testing and Materials, ASTM D 1683. The method of claim 1,
A method for producing an airbag cushion having an elongation of 15% to 80% as measured by the method of the American Society for Testing and Materials, ASTM D 1683. The method of claim 1,
A method of manufacturing an airbag cushion, in which the maximum pressure is 100 kPa or more when the initial airbag cushion is inflated when an instantaneous pressure of 25 bar is injected into the airbag cushion. A needle thread for sewing the fabric fabric, and a needle thread for tensioning the upper thread sewing thread, and an auxiliary thread thread tensioning force for the upper thread sewing thread supplied to the main thread thread adjusting thread. Equipped along the path of the sewing machine,
Sewing device for the airbag cushion further comprises a control means for finely adjusting the preliminary tension according to the thread adjuster. The method of claim 7, wherein
The preliminary tension according to the thread adjusting device sewing machine of the airbag cushion so that the tension of the upper thread sewing thread when sewing in the reverse direction is 105% to 140% compared to the tension of the upper thread sewing thread when sewing in the forward direction.

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