KR101601241B1 - 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, and more particularly to an airbag cushion including an airbag cushion and an airbag system including the airbag cushion, wherein the airbag cushion includes an airbag system including at least one fabric- And the tension of the upper thread sewing thread is set to be in the range of 105% to 140% with respect to the tension of the upper thread sewing thread at the time of sewing in the forward direction, and an airbag cushion sewing apparatus.
According to the present invention, the tension of the sewing thread is adjusted to the optimum range, and the operation stability and the airbag deployment performance are excellent. In addition, by having excellent shape stability and air blocking effect, the impact applied to the passenger is minimized, An airbag cushion can be manufactured.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a method of manufacturing an airbag cushion,

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

Generally, an air bag is used to detect a collision shock applied to a vehicle at the time of a frontal collision at a speed of about 40 km / h or more at a speed of about 40 km / h by a shock sensor, The airbag cushion system according to the present invention is a device that protects a driver and a passenger by inflating and expanding the airbag cushion.

1, a typical airbag cushion system includes an inflator 121 that generates gas by ignition of a primer 122, an airbag cushion 124 that is inflated and deployed toward the driver of the driver's seat by the generated gas, An airbag cushion module 100 mounted on the steering wheel 101, an impact sensor 130 for generating an impact signal in the event of an impact, and an electronic igniter for igniting the primer 122 of the inflator 121 And an electronic control module (110). The airbag cushion system configured as described above senses an impact in the impact sensor 130 and transmits a signal to the electronic control module 110 when the vehicle collides head-on. At this time, the electronic control module 110 recognizing this ignites the primer 122 to burn the gas generating agent in the inflator 121. The gas generating agent thus combusted expands the airbag cushion 124 through rapid gas generation. The airbag cushion 124 inflated and deployed partially absorbs the impact load caused by the collision while contacting the front upper body of the driver, and the airbag cushion 124, which is inflated while the driver's head and chest are moved forward due to 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 buffered on the front portion of the driver. Accordingly, by effectively cushioning the impact force transmitted to the driver in the frontal collision, it is possible to reduce the secondary injury.

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

At this time, typically, the sewing-type airbag includes a sewing part for joining the fabric and the fabric. That is, since the portion of the air bag that is mainly discharged with air is a sewing portion, the properties such as the seam strength and elongation of the sewing portion are important. Particularly, in order to exhibit excellent inflating performance and expansion performance when the air bag is deployed due to rapid gas generation or the like, the bonding performance of the entire air bag cushion should be effectively maintained.

However, the sewing-type airbag to which the conventional automatic sewing machine is applied is insufficient to provide the inflating performance and the developing performance when the airbag is operated, such as the seam strength and elongation of the sewing part. This problem is limited only by changing the material of the sewing machine applied to the sewing machine, and there is a desperate need to develop a technique for optimizing the physical properties of the sewing machine without changing the material.

Therefore, there is a need for studies on the manufacturing process of an airbag cushion and the development of a sewing apparatus capable of forming a sewing part having excellent mechanical properties and air-blocking effect so as to exhibit excellent inflating performance and developing performance when the airbag is deployed.

The present invention provides a method for manufacturing an airbag cushion having excellent air-tightness and pressure-holding capability by adjusting the tension of a sewing thread to an optimum range.

The present invention also seeks to provide an airbag cushion sewing apparatus capable of forming a sewing portion of an airbag cushion having excellent air-tightness and pressure-holding capability.

The present invention relates to a method for sewing a sewing thread, comprising the steps of: cutting at least one fabric-made fabric, and sewing and bonding the fabric member, wherein the sewing- To 105% to 140% relative to the airbag cushion.

The present invention also provides a sewing machine comprising a main thread adjuster for applying tension to an upper thread sewing thread and a thread thread adjuster for imparting a tension to the upper thread sewing thread supplied to the main thread adjuster, And a control means for finely adjusting a pretensioning force of the thread tension adjuster in the middle of the path of the sewing thread of the upper thread from the needle thread to the needle.

Hereinafter, a method of manufacturing an airbag cushion according to a specific embodiment of the present invention and an airbag cushion sewing apparatus that can be used in such a process will be described in detail. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims.

In addition, throughout this specification, "comprising" or "containing ", unless specifically stated, refers to including any and all components (or components) Can not be interpreted as excluding.

The present invention improves the sealing strength and elongation of the sewing part and improves the internal pressure maintaining performance so as to exhibit excellent developing performance in inflating the airbag by applying the sewing conditions optimized for the sewing part for joining in the manufacture of the airbag cushion and the sewing method therefor .

Airbag cushions are typically made by sewing and joining fabrics to define the inflated portion of the inflator when it bursts. More specifically, in manufacturing an airbag cushion by sewing a fabric for an airbag with an automatic sewing apparatus by a general method, a lower thread 201 and an upper thread 202 are formed on a fabric made of a fabric 200, And sewing proceeds while the upper thread 202 is supplied in a predetermined direction to the lower thread 201 from the sewing machine. At this time, the sewing machine moves while the needle of the sewing machine moves in a different direction while the fabric 200 is fixed, and sewing proceeds while the upper thread 202 is supplied in the same direction as the needle.

Therefore, even when sewing the fabric constituting one airbag cushion, the feeding direction of the upper thread to the lower thread 201 can be changed, and therefore, the feeding direction of the upper thread 202 with respect to the lower thread 201 can also be changed (see FIG.

Depending on the feeding direction of the upper thread 102, "forward" or "reverse" may be defined. 2, 3, and 5, the feeding direction of the upper thread 202 in which the upper thread 202 can proceed sewing without being twisted with respect to the lower thread 201, (See FIGS. 2, 3 and 5), and the "reverse direction" is a direction in which the upper thread 202 is twisted about the lower thread 201, as shown in FIGS. 2 and 4, (Refer to Figs. 2, 4, and 6). The sewing direction of the upper thread 202 and the sewing direction of the upper thread 202 may be defined as follows.

In the sewing direction, that is, the "forward" direction or the "reverse direction", whether or not the upper thread 102 is twisted with respect to the lower thread 100 is changed, and between the sewing threads sewn in the "forward" The required length of the sewing machine is varied, and the bonding performance of the sewing part is varied.

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

Accordingly, the present invention prevents deterioration of mechanical properties when sewing in the reverse direction, so that both the first sewed portion sewn in the forward direction and the second sewed portion sewed in the reverse direction are uniformly ensured to have excellent mechanical properties, It is possible to obtain an improved physical property improvement effect even in the expansion performance of the substrate.

According to an embodiment of the present invention, there is provided a method of manufacturing an airbag cushion that optimizes the tension of an upper thread sewing thread to a predetermined range. A method of manufacturing such an airbag cushion includes the steps of cutting one or more textile fabrics, and sewing and bonding the fabric, wherein the sewing and bonding process includes a step of sewing the upper thread in the reverse direction, And may be adjusted to be from 105% to 140%, preferably from 107% to 135%, and more preferably from 110% to 130%, relative to the tension of the sewing thread.

In this case, when the tension range of the sewing thread in the reverse direction is applied in a forward direction with less than 105% of the sewing tension, the mechanical properties of the second sewing portion sewn in the reverse direction are remarkably lowered and the air- And thus the developing performance may be significantly deteriorated. In addition, if the tension of the sewing thread in the reverse direction is greater than 140% of the tension during sewing in the forward direction, the entire process may not be performed smoothly or the strength of the sewing portion may be too high Strength may damage the fabric or cause the deployment time or shape of the airbag to unfold during deployment of the airbag.

Also, the sewing and bonding step may be performed such that the length of the upper thread sewing thread per unit length of the fabric between the first sewing part sewn in the forward direction and the second sewing part sewed in the reverse direction has a deviation of 15% or less. That is, in the sewing and bonding step, the sewing thread required length (L ₁ ) of the first sewing part sewed in the forward direction per unit length of the airbag cushion cloth and the deviation (L ₁ ) of the sewing thread required length (L ₂ ) of the second sewing part sewed in the reverse sewing direction ) Is 15% or less or 1% to 15%, preferably 12% or 1.5% to 12%, more preferably 10% or 2% to 10%. Particularly, the required length deviation (DELTA L) of the sewing thread in the first sewing section and the second sewing section can be expressed by the following equation (1).

[Equation 1]

Where L ₁ is the length of the sewing thread per unit length of the fabric in the first sewed portion sewn in the forward direction and L ₂ is the sewing length per unit length of the fabric in the second sewing portion sewn in the reverse direction.

The first takes bongjesa between the sewing unit and second sewing unit length variation (△ L) takes bongjesa per unit length of the fabric in a second sewing portion of sewing the opposite direction length (L ₂₎ of the first garment in the normal direction from the 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 required length deviation (DELTA L) of the sewing needles between the first sewing part and the second sewing part sewn in the forward direction and the reverse direction is more than 15%, the second sewing part sewed in the reverse direction as compared with the first sewing part sewed in the forward direction The mechanical properties of the sewing part are remarkably deteriorated and the air blocking performance and the pressure resistance performance of the airbag cushion may be greatly deteriorated due to the difference in physical properties between the first sewing part and the second sewing part.

In addition, in the sewing and bonding step, when adjusting the tension of the upper thread in the forward and reverse sewing to an optimum range, the type of the sewing thread used in the first sewing portion sewn in the forward direction and the sewing portion used in the second sewing portion sewed in the reverse direction, A more preferable effect can be obtained when the thickness, the sewing method, the number of stitches, and the like are applied in the same manner.

As described above, according to the present invention, the physical properties of the airbag cushion can be optimized by adjusting the tension of the upper thread sewing thread according to the sewing direction to the optimum range. Particularly, according to the present invention, when the sewing of the upper thread sewing thread is performed in the reverse direction, the tension of the upper thread sewing thread is optimized to be 105% to 140% in comparison with the tension of the upper thread sewing thread at the time of sewing, In addition, it is possible to obtain improved physical properties, such as excellent air-blocking performance, airtightness, and expansion performance.

In the sewing and bonding step, a sewing yarn including at least one selected from the group consisting of a nylon yarn, a polyester yarn, a polyolefin yarn, and an aramid yarn can be used. In terms of heat resistance and shrinkability, nylon 66, nylon 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 210 to 1,260 denier, preferably 840 to 1,260 denier. In terms of strength, the thickness of the sewing thread is preferably 210 denier or more, Is preferably 1,260 denier or less. The denier is a unit indicating the thickness of a yarn or a fiber, and is 1 denier when the length is 9,000 m is 1 g.

In addition, the above-mentioned sewing yarn can be used at a tensile strength of 58 N or more, preferably 58 N to 110 N, measured by the method of American Society for Testing and Materials ASTM D 204-97, preferably 89 N To 110 N for 840 denier, and 58 N to 80 N for 840 denier. When 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 at the time of manufacturing or expanding the airbag. When the tensile strength is too large, the strength of the sewing part is too strong, The development time point or shape of the object may be abnormally developed.

In the sewing and bonding process of the present invention, an effective sewing method can be selected and applied according to the use of each part, and at least one sewing method from among a single lock, a double lock, a single chain, and a double chain can be applied.

The sewing and bonding step may be performed by adjusting the number of stitches to an optimum range according to the use of each part or the sewing method, preferably 20 to 80 ea / 100 mm, more preferably 25 to 75 ea / 100 mm , More preferably 30 to 70 ea / 10 mm, and sewing and bonding can be performed. If the number of stitches is less than 20 ea / 100 mm, the strength of the sewing portion is too weak, and the sewing portion may be torn at the time of manufacture or expansion. If the number of stitches exceeds 80 ea / 100 mm, The time or shape of the deployment of the airbag may be unfavorably developed upon damage or deployment of the airbag.

According to the present invention, the sewing-bonded sewing portion having the optimum tension of the sewing thread according to the present invention has a seam strength of 100 to 400 kgf / inch, preferably 130 to 350 kgf / inch, as measured by the method of ASTM D 1683, Lt; RTI ID = 0.0 > kgf / inch. ≪ / RTI > In addition, the elongation measured by the method of American Society for Testing and Materials ASTM D 1683 may be from 15% to 80%, preferably from 20% to 70%, and most preferably from 25% to 60%. It is preferable that the sewing portion of the airbag cushion manufactured according to the present invention maintains the seam strength and elongation in the above range in terms of securing the strength of the sewing portion to an optimum range and achieving effective pressure maintaining performance.

Further, when 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 (deployment) is preferably 100 KPa or more, Preferably 105 KPa, and more preferably 110 KPa or higher. With such excellent pressure resistance maintenance performance, the airbag cushion of the present invention can exhibit excellent performance as a safety system when mounted on a vehicle airbag system.

 In a preferred example of the present invention, the internal pressure of the airbag cushion can be measured using an apparatus as shown in Fig. In the above measuring apparatus, the primary high-pressure tank is filled with nitrogen at a high pressure, and then the first solenoid valve is opened by a computer so that nitrogen gas can be filled up to 25 bar in the secondary tank. When the secondary tank is filled, the first solenoid valve is closed, the second solenoid valve is opened by the computer, and the compressed nitrogen gas charged at the pressure of 25 bar in the secondary tank is instantaneously maintained at atmospheric pressure The airbag cushion is released and the airbag cushion is deployed. At this time, the initial maximum pressure inside the airbag cushion is measured through a pressure sensor and recorded by a computer.

Accordingly, the airbag cushion manufactured as described above preferably has an initial maximum pressure of 100 KPa or more when injected at an instantaneous pressure of 25 bar satisfying the above conditions, a seam strength of the sewing portion of 100 kgf / inch or more, Elongation can be below 80%.

On the other hand, fabric made of fabric which can be used in the manufacture of an airbag cushion according to the present invention may be any fabric or nonwoven fabric known to be usable for manufacturing an airbag cushion in this field, and is not limited to that kind. For example, the fabric or the nonwoven fabric may be a fabric or a nonwoven fabric comprising fibers selected from the group consisting of nylon-based fibers, polyester-based fibers, polyolefin-based fibers, and aramid-based fibers. For example, a fabric made of a fabric including nylon 66, polyethylene terephthalate (PET), or polypropylene (PP) or the like can be used. The type of woven fabric or the type of nonwoven fabric used in the present invention is not particularly limited, but it is preferable to use nylon 66 or the like when considering the strength of the sewn portion.

The textile fabric may be fabricated into an airbag cushion fabric through a conventional weaving process, refining and heat setting processes, and then, if necessary, further processed, such as a silicone rubber coating. The airbag cushion fabric thus coated is cut and sewed as described above to produce a certain type of airbag cushion. At this time, the airbag cushion is not limited to a particular shape and can be manufactured in a general shape.

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

At this time, the coating amount per unit area of the rubber component coating layer may be 20 to 200 g / m ² , preferably 20 to 100 g / m ² . In particular, in the case of producing a side curtain type airbag of OPW (One Piece Woven) type, 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 > is preferred.

Further, in the airbag cushion manufacturing method of the present invention, the sewing and bonding step may be performed by any device known to be applicable to a sewing-type airbag, and may be operated by using an industrial sewing machine or the like, . Particularly, a separate sewing thread tension adjusting means may be additionally used to adjust the sewing thread tension of each sewing thread in the forward and reverse directions to an optimum range. The sewing thread tension adjusting means may be a manual controller, a digital controller contoller.

According to another embodiment of the present invention, there is provided an apparatus for sewing an airbag cushion capable of optimally adjusting a tension of a sewing machine to a predetermined range. The airbag cushion sewing apparatus includes a needle for sewing and bonding a cloth material, a main thread adjuster for applying a tension to an upper thread sewing thread, and a thread tension adjuster for applying a tension to an upper thread sewing thread supplied to the main thread adjuster, And further includes adjusting means for finely adjusting the pretensioning force according to the thread thread adjuster during the path of the needle thread sewing thread from the yarn supply source to the needle.

In the airbag cushion sewing apparatus, the preliminary tension according to the thread thread adjuster is 105% to 140%, preferably 107% to 135%, more preferably 10% to 140% And preferably from 110% to 130%. In addition, in the sewing apparatus, the tension of the upper thread sewing thread may be applied such that the length of the upper thread sewing thread per unit length of the fabric between the first sewing portion sewn in the forward direction and the second sewing portion sewed in the reverse direction is 15% or less.

8, the airbag cushion sewing apparatus 800 includes a needle 801 for sewing and bonding a fabric made up of fabric, and a sewing machine 800 for sewing the upper thread sewing thread 802 A yarn adjuster 803 and a yarn yarn adjuster 804 for supplying a preliminary tension to the upper yarn sewing yarn supplied to the yarn adjusting device are provided in the middle of the path of the upper yarn sewing yarn 802 from the yarn supply source to the needle 801, It may further comprise adjustment means 805 for fine adjustment of the preliminary tension according to the partial adjuster 804.

The main thread adjuster 803 includes means for stably supplying an upper thread sewing thread to a needle 801 and maintaining a constant tension. The tension applied by the main thread adjuster 803 can be realized by manually setting a fixed value according to the type of the sewing machine, the number of sewing stitches, the type of fabric, and the like.

The spindle adjuster 804 includes a means for finely adjusting the tension adjusted by the main spindle adjuster 803 by applying a preliminary tension to the main spindle adjuster 803. The tension imparted by the thread tension adjuster 804 can be realized by finely assigning manually fixed values according to the type of the sewing machine, the stitch number of the sewing thread, the kind of the fabric, and the like.

The adjusting means 805 for finely adjusting the preliminary tension according to the thread tension adjuster 804 may include a means for automatically adjusting the tension difference of the sewing portion according to the sewing direction by finely adjusting the tension to be changed according to the sewing direction Respectively. The application of the tension by the preliminary tension fine adjustment means 805 can adjust the tension application by automatically adjusting the upper thread sewing thread according to the sewing direction.

The preliminary tension fine adjustment means 805 may be manually operated or operated by a digital controller through computer programming or the like. In particular, as shown in FIG. 8, the preliminary tension fine adjustment means 805 can sufficiently lower the tension on the upper thread sewing thread when sewing in the forward direction (indicated by a dotted line), and adjusts the tension of the upper thread sewing thread in the reverse direction (Indicated by a solid line).

As described above, the airbag cushion sewing apparatus of the present invention is characterized in that the airbag cushion sewing apparatus of the present invention further comprises a preliminary tension fine adjustment means in addition to the main thread regulator and the side thread regulator, So that the automatic adjustment can be made possible.

According to another embodiment of the present invention, there is provided an airbag cushion manufactured according to the above-described method. Particularly, the airbag cushion may be manufactured by optimizing the tension of the upper thread sewing thread to a predetermined range, and the airbag cushion may be processed into a conventional shape well known to those skilled in the art.

The airbag cushion is formed such that the sewing thread required length L ₁ of the first sewing part sewed in the forward direction per unit length of the airbag cushion cloth and the deviation ΔL of the sewing thread required length L ₂ of the second sewing part sewed in the reverse direction is 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%.

Further, according to another embodiment of the present invention, there is provided an airbag system including an airbag cushion manufactured according to the above-described method. In particular, the airbag system may comprise an airbag cushion that is manufactured by optimizing the tension range of the sewing thread to a predetermined range, and the airbag system may comprise conventional devices well known to those skilled in the art.

The airbag can be largely divided into a front air bag (front air bag) and a side air bag. The front airbags are of a driver type, a passenger's seat, a knee, an ankle and the like, and the side airbags are a side airbag of a car and a curtain airbag. Accordingly, the airbag may be a front type airbag, a side airbag or a curtain type 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 excellent in operational stability and airbag deployment performance of a sewing part, and an apparatus for sewing an airbag cushion which can be used for the method.

In particular, by optimizing the tension of the sewing thread to a predetermined range, it is possible not only to manufacture an airbag cushion having improved seam strength and elongation of a sewing part and having an excellent pressure-holding ability so as to exhibit excellent developing performance upon inflating an airbag, The airbag cushion thus manufactured provides excellent shape stability and air-blocking effect and minimizes shock to the passenger, thereby safely protecting the passenger.

Therefore, the airbag cushion manufactured in accordance with the present invention can be very preferably used for an airbag system for a vehicle.

1 shows a typical airbag system.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an airbag cushion, and more particularly, to an airbag cushion which includes a first sewing part sewed in a forward direction and a second sewing part sewed in a reverse direction.
3 is a schematic view showing a structure of an upper thread and a lower thread of a first sewing part sewn in a forward direction in an airbag cushion according to an embodiment of the present invention.
4 is a schematic view showing a structure of an upper thread and a lower thread of a first sewing part sewed in a reverse direction in an airbag cushion according to an embodiment of the present invention.
5 is a photograph showing a structure of an upper thread and a lower thread of a first sewing part sewn in a forward direction in an airbag cushion according to an embodiment of the present invention.
6 is a photograph showing the structure of the upper thread and the lower thread of the second sewing part sewed in the reverse direction in the airbag cushion according to the embodiment of the present invention.
7 is a schematic view showing an apparatus for measuring internal pressure of an airbag cushion according to an embodiment of the present invention.
8 is a schematic view showing an apparatus for sewing an airbag cushion according to an embodiment of the present invention.
9 is a graph showing the results of measuring the internal pressure of an airbag cushion including a sewing part according to the first embodiment of the present invention.
10 is a graph showing the result of measurement of the internal pressure of an airbag cushion including a sewing portion 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

The fabric was weaved under the conditions shown in Table 1 below and then coated with a non-coated cloth or a knife over roel coating method through a refining and tentering process, The fabric was used as a fabric for a cushion. The fabric was cut using a laser cutter, and the sewing and bonding step of the fabric was performed using the sewing machine as shown in Fig. The above-described sewing and bonding process was applied to sewing conditions as shown in Table 1 below to produce an airbag cushion.

The types of the sewing thread, the sewing method, the number of stitches, the tension, the kind of the fabric, the weaving pattern, the coating composition, and the coating amount are 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 ASTM D 206-97, and the first sewing portion sewn in the forward direction and the second sewing portion sewed in the reverse direction, The required length of the upper thread per unit length (10 cm) is shown. Also, the types of sewing yarn used in the first sewing part and the second sewing part, sewing method, number of stitches, and the like are applied in the same manner. The remaining conditions were in accordance with the usual conditions for manufacturing the airbag cushion.

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 the following Table 1. The properties of the airbag cushions were measured and are shown in Table 1 below.

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

a) Seam strength and elongation

Seal strength and elongation were measured for each of the first sewed portion sewn in the forward direction and the second sewed portion sewed in the reverse direction in the airbag cushion.

First, the specimen of the airbag cushion was fixed to the lower clamp of the measuring device according to the method of ASTM D 1683 of the American Society for Testing and Materials, and the upper clamp was moved upward to measure the seam strength and elongation at break of the airbag cushion specimen.

b) Measuring the internal pressure when inflating the airbag cushion

As shown in Fig. 7, a nitrogen compressed gas of 25 bar was injected momentarily into the air to develop the airbag cushion, and then the change of the internal pressure of the airbag was observed over time. The maximum internal pressure at the time of initial airbag inflation Respectively. Particularly, it is preferable to electronically control the operation to minimize the error, and therefore, an electronic control device is used for the air injection and interruption operation.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Type of sewing machine Nylon 66 Nylon 66 Nylon 66 Nylon 66 Tensile strength of sewing thread (N) 100.9 107.8 100.9 107.8 Total size of stitches (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 Tension (%) 110 125 100 145 Types of Fabric Nylon 66 Nylon 66 Nylon 66 Nylon 66 The total fineness of the fabric (de) 420 420 420 420 Weaving density of fabric 49X49 49X49 49X49 49X49 Weaving type of fabric (plain weave / OPW) Plain weave Plain weave Plain weave Plain weave Rubber component silicon silicon silicon silicon Amount of rubber coating (g / m ² ) 25 25 25 25 Length of first sewing unit upper thread (mm) 329 324 330 Not sewable Length of the second sewing unit upper thread (mm) 344 335 390 Not sewable The first sewing part / second sewing part
Upper thread deviation (%) 4.6 3.4 16.7 Not sewable Strength of first sewing part (kgf) 233 231 238 Not sewable Second Seal Strength (kgf) 219 221 170 Not sewable Elongation at first sewn portion (%) 48 47 51 Not sewable Elongation percentage of the second sewn part (%) 52 50 87 Not sewable Maximum internal pressure at expansion (kPa) 125 126 97 Not sewable

9 and 10 are graphs showing the results of the internal pressure measurement during inflation of the airbag cushions of Example 1 and Comparative Example 1, respectively.

As shown in Table 1, in the case of Examples 1 and 2 in which the tension of the sewing yarn was optimized in the normal direction and the reverse direction, the sewing portion of the airbag cushion ensured uniform bonding performance as a whole, It can be understood that the maximum pressure is 125 to 126 kPa when the cushion is inflated, and that the pressure resistance is excellent. Particularly, the airbag cushions manufactured according to Examples 1 and 2 show that the seam strength and elongation of the sewed backwardly sewn portion are similar to the seam strength and elongation of the forwardly sewn sewing portion, Can be confirmed.

On the other hand, in the case of Comparative Example 1 in which the forward and reverse sewing machine tensions are applied in the same manner as the conventional sewing machine, the sewing strength and elongation are remarkably reduced, and uniform and excellent sewing bonding performance is not provided as a whole. Particularly, in the airbag cushion manufactured according to Comparative Example 1, the elongation of the second sewn portion sewn in the reverse direction is about 87%, and the elongation of the second sewn portion is about 170% ≪ / RTI > Accordingly, the seam strength of the second sewed portion sewn in the reverse direction in the airbag cushion of Comparative Example 1 is only about 71% that of the first sewed portion sewed in the forward direction, so that the maximum pressure at the initial airbag inflation 97 kPa, indicating that the overall physical properties and overall performance of the airbag cushion are poor.

In the case of Comparative Example 2 in which the tension of the upper thread sewing thread is sewn in the reverse direction and the tension of the upper thread sewing thread is applied in the forward direction with respect to the tension of the upper thread sewing thread at the time of sewing, the sewing thread is excessively tensioned, Was impossible.

Therefore, as described above, it can be seen that an airbag cushion excellent in work stability and airbag deployment performance of the sewing part, excellent in form stability and air-blocking effect can be manufactured by adjusting the tension of the sewing thread to an optimum range have.

Claims (8)

Cutting one or more fabric stocks, and
Sewing and bonding the fabric member;
The sewing and bonding step
A sewing machine for an airbag cushion comprising: a needle for sewing a fabric-made fabric; and a yarn conditioner for imparting a predetermined tension to the sewing thread of the upper thread;
A reverse sewing joining step in which sewing is performed while an upper thread sewing thread is twisted with respect to the lower thread sewing thread, and a forward sewing joining step in which the upper thread sewing thread is sewed without being twisted to the lower thread sewing thread;
The tension applied to the upper thread sewing thread by the yarn conditioner in the reverse sewing and bonding step is adjusted to be 105% to 140% with respect to the tension imparted to the upper thread sewing thread in the forward sewing thread joining step, and the reverse and forward sewing joining steps Wherein the airbag cushion has an airbag. The method according to claim 1,
Wherein the sewing and bonding step is applied with at least one sewing method selected from the group consisting of a single lock, a double lock, a single chain, and a double chain. The method according to claim 1,
Wherein the sewing and bonding step is applied so that the number of stitches is 20 to 80 ea / 100 mm. The method according to claim 1,
Wherein the sewing part formed by the sewing and bonding step has a seam strength of 100 to 400 kgf / inch measured by the method of ASTM D 1683 of the American Society for Testing and Materials. The method according to claim 1,
Wherein the sewing portion formed by the sewing and bonding step has an elongation of 15% to 80% as measured by the method of ASTM D 1683 of the American Society for Testing and Materials. The method according to claim 1,
Wherein an initial pressure of 25 bar is applied to the airbag cushion so that the maximum pressure when the initial airbag cushion inflates exceeds 100 kPa. The method according to claim 1,
In the airbag cushion sewing apparatus, the yarn conditioner
A yarn conditioner for imparting a tension to an upper thread sewing yarn and a yarn thread adjuster for giving a preliminary tension to an upper thread sewing yarn supplied to the yarn adjusting device are provided on the path of an upper thread sewing yarn from a yarn supply source to a needle,
Further comprising adjusting means for finely adjusting a preliminary tension according to the partial seal regulator. 8. The method of claim 7,
The tension imparted to the upper thread sewing thread in the reverse sewing and bonding process is controlled to be 105% to 140% of the tension imparted to the upper thread sewing thread in the forward sewing and bonding process due to the preliminary tension imparted by the thread tension adjuster A method of manufacturing a cushion.

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