KR20170079784A - Cover for Airbag Cushion and Method for Manufacturing The Same - Google Patents

Abstract

A cover for an airbag cushion that maintains the folded state of the airbag cushion and enables adjustment of the deployment time and the deployment angle when the airbag cushion is deployed by the inflator, and a method of manufacturing the same. The cover of the present invention is formed of a nonwoven fabric and is not opened when the airbag cushion is deployed; A slit incision to be opened when the airbag cushion is deployed; And at least one delay portion for delaying the opening of at least a portion of the slit incision. The delay unit has an ultrasonic welding portion.

Description

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

The present invention relates to a cover for an airbag cushion, and more particularly, to a cover for an airbag cushion that maintains the folded state of the airbag cushion and enables adjustment of the deployment time and the deployment angle when the airbag cushion is deployed by the inflator, And a manufacturing method thereof.

When the impact sensor senses an impact applied to the vehicle in the event of a collision or rollover of the vehicle, the airbag cushion is inflated to protect the driver and the passenger from accidents.

A typical airbag system includes an airbag module, a shock detection sensor that generates an impact signal when the vehicle collides or overturns, and an electronic control module that controls the airbag module in response to the impact signal.

The airbag module includes a primer ignited by the electronic control module, an inflator generating gas by ignition of the primer, and an airbag cushion inflated and deployed by the generated gas.

When a vehicle collision or rollover occurs, the impact sensor transmits an impact signal to the electronic control module. The electronic control module, which receives the shock signal from the impact sensor, ignites the primer and burns the gas generating agent inside the inflator. Gas is rapidly generated by the combustion of the gas generating agent, whereby the airbag cushion rapidly expands.

The collision is buffered by gas escape through the exhaust hole formed in the airbag cushion when the driver or passenger collides with the inflated and deployed airbag cushion.

The airbag includes a front airbag for protecting the driver or a passenger from a frontal collision, a curtain airbag installed along the upper side of the inside surface of the vehicle to protect the head portion of the driver or the passenger from a side collision by being curtained when inflated, A side airbag mounted on the side of the door or the seat so as to protect the side of the driver or the passenger from collision, and the like.

These various types of airbag cushions are manufactured in a certain shape and then mounted on the vehicle in a folded state to minimize the volume thereof. At this time, the airbag cushion is covered with a cover to maintain the folded state of the airbag cushion. The cover for a conventional airbag cushion has a cutout at the center so that the airbag cushion can be easily torn when it is deployed.

However, in the event of a vehicle accident, the airbag cushion is deployed while the incision is broken at a time or in an uncontrolled manner, so that passenger protection from a vehicle accident has not been sufficiently achieved.

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a cover for an airbag cushion and a method of manufacturing the same, which can prevent problems due to limitations and disadvantages of the related art.

One aspect of the present invention is to provide a cover for an airbag cushion that maintains the folded state of the airbag cushion and enables adjustment of the deployment time and the deployment angle when the airbag cushion is deployed by the inflator.

Another aspect of the present invention is to provide a method of manufacturing a cover for an airbag cushion that maintains the folded state of the airbag cushion and enables adjustment of the deployment time and the deployment angle when the airbag cushion is deployed by the inflator.

Other features and advantages of the invention will be set forth in the description which follows, or may be learned by those skilled in the art from the description.

According to one aspect of the present invention, there is provided a cover for an airbag cushion formed of a nonwoven fabric, comprising: a seam area which is not opened when the airbag cushion is deployed; A slit-cutting area to be opened when the airbag cushion is deployed; And at least one delaying area for delaying the opening of at least a part of the slit cutout, wherein the delay part has an ultrasonic welded part.

The delay unit may have the ultrasonic fused portions of 2 to 5/100 mm spaced apart at a predetermined interval.

The ultrasonic welds may have a length of 2 to 20 mm and a width of 1 to 10 mm.

The slit incision part may be located on the opposite side of the inflator, and the ultrasonic fused part may be spaced from the slit incision part by 0.5 to 2 cm toward the inflator.

The nonwoven fabric may be formed of polyethylene terephthalate (PET).

The sewing section may include at least one of a nylon yarn, a polyester yarn, a polyolefin yarn, and an aramid yarn as a sewing thread.

The sewing portion may have a number of stitches of 10 to 35/100 mm.

The sewing portion may be formed in at least one of a single lock, a double lock, a single chain, and a double chain.

The slit cutout may have a plurality of slits and a plurality of bridges alternately arranged in a straight line.

The length of each of the slits parallel to the straight line is 0.5 to 2 cm, and the length of each of the bridges parallel to the straight line may be 0.5 to 1 cm.

The sum of the lengths of the plurality of slits may be 60 to 90% of the length of the slit cutout.

According to another aspect of the present invention, there is provided a method of manufacturing a nonwoven fabric, Forming a plurality of slits in a row in the nonwoven fabric, thereby forming a slit incision having the slits and bridges therebetween; Folding the nonwoven fabric along the slit incision; Sewing at least a portion of the folded nonwoven fabric to form a sewn portion that is not open when the airbag cushion is deployed; And forming at least one delay portion for delaying the opening of at least a part of the slit incision by performing ultrasonic welding for a portion spaced a predetermined distance from the slit incision portion A method of manufacturing a cover can be provided.

The nonwoven fabric may be formed of polyethylene terephthalate (PET), and the ultrasonic welding may be performed by applying ultrasonic waves at a frequency of 5 to 15 kHz for 0.5 to 3 seconds.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the invention as claimed.

The cover for an airbag cushion of the present invention maintains the folded state of the airbag cushion without disturbing the deployment of the airbag cushion by easily tearing it by an appropriate force when the airbag cushion is deployed by the inflator.

Further, the cover for an airbag cushion of the present invention can more safely protect a passenger from a vehicle accident by allowing the deployment time and the deployment angle of the airbag cushion to be adjusted as needed.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
1 schematically shows a cover for an airbag cushion according to an embodiment of the present invention.

Hereinafter, a cover for an airbag cushion of the present invention and a method of manufacturing the same will be described in detail with reference to the accompanying drawings.

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. Therefore, the present invention encompasses all changes and modifications that come within the scope of the invention as defined in the appended claims and equivalents thereof.

1, the cover 100 for an airbag cushion of the present invention includes a sewing portion 110 that is not opened when the airbag cushion is deployed, a slit cutout portion 120 that is opened when the airbag cushion is deployed, And at least one delay unit (130) for delaying the opening of at least a part of the slit cutout (120).

The cover 100 for the airbag cushion of the present invention may be made of a nylon 66 flat fabric or wrap, but the cover 100 for airbag cushion according to an embodiment of the present invention may be made of a nonwoven fabric, preferably polyethylene terephthalate It is made of phthalate (PET) nonwoven fabric. The PET nonwoven fabric can be manufactured at a lower cost than the nylon 66 plain weave fabric, so that the manufacturing cost of the airbag cushion cover 100 can be reduced.

The kind of the nonwoven fabric is not particularly limited, but a spunbond nonwoven fabric may be preferably used.

The thickness of the nonwoven fabric is not particularly limited, but may preferably be 0.25 to 0.35 mm, more preferably 0.27 to 0.33 mm (measured in accordance with ASTM D 1777). When the thickness of the nonwoven fabric is less than 0.25 mm, the MD and TD tensile strengths (measured in accordance with ASTM D 5035) are less than 30 kgf / 5 cm and less than 15 kgf / 5 cm, respectively, The folded state of the airbag cushion can not be continuously maintained. On the other hand, when the thickness of the nonwoven fabric exceeds 0.35 mm, the tensile strength in the MD direction and the TD direction exceeds 45 kgf / 5 cm, thereby deteriorating the deployment performance of the airbag cushion.

As illustrated in FIG. 1, the slit cutout 120 may be located on the opposite side of the inflator as a portion to be opened when the airbag cushion is deployed. The slit cutout 120 may have a plurality of slits 121 and a plurality of bridges 122 alternately arranged in a straight line. That is, by forming a plurality of slits 121 in a line on the nonwoven fabric by using a laser cutter or a blade cutter, the slit cutter 120 having the slits 121 and the bridges 122 therebetween . The slits 121 may be formed in a row in the MD direction of the nonwoven fabric (i.e., the direction in which the carded web proceeds on the tray when the nonwoven fabric is produced) or the TD direction.

The length (parallel to the straight line) of each of the slits 121 may be 0.5 to 2 cm, preferably 0.7 to 1.5 cm. The length (parallel to the straight line) of each of the bridges 122 between the slits 122 may be 0.5 to 1 cm, preferably 0.6 to 0.8 cm. The sum of the lengths of the plurality of slits 121 may be 60 to 90%, preferably 65 to 85% of the length of the slit cutout 120.

In the cover 100 for an airbag cushion of the present invention, the directions of the slit cutout 120 and the slits 121 are appropriately selected according to the volume and degree of compression of the folded airbag cushion, May be formed in the MD direction, the TD direction, or the diagonal direction of the nonwoven fabric.

The slit cutout 120, which is the portion to be opened when the airbag cushion is deployed, may have a seam strength (measured in accordance with ASTM D 1683) of 1 to 6 kgf / inch, preferably 1.5 to 5.5 kgf / inch. If the seam strength is less than 1 kgf / inch, there is a danger that the slit cutout 120 will easily tear when assembling the airbag. On the other hand, when the seam strength exceeds 6 kgf / inch, another portion of the cover 100 is torn when the airbag cushion is deployed, which may cause the airbag cushion to develop in an abnormal shape or deploy the airbag cushion at an abnormal point in time.

After the slit cutout 120 is formed, the nonwoven fabric is folded along the slit cutout 120 and at least a portion of the folded nonwoven fabric is sewed to form a sewing part 110 that is not opened when the airbag cushion is deployed .

The sewing part 110 may be made of at least one of nylon yarn, polyester yarn, polyolefin yarn, and aramid yarn with a stitch number of 10 to 35/100 mm, preferably 15 to 30/100 mm, And sewing and folding the folded nonwoven fabric. If the number of stitches is less than 10/100 mm, the strength of the sewing part 110 is too weak to open the part of the cover 100 which should not be opened when the cover 100 is manufactured or when the airbag cushion is deployed May occur. On the other hand, if the number of stitches exceeds 35/100 mm, the strength of the sewing part 110 is excessively high, which may damage the nonwoven fabric.

The sewing part 110 may be formed in at least one of a single lock, a double lock, a single chain, and a double chain.

The sewing portion 110 is a portion that is not opened when the airbag cushion is deployed. The sewing portion 110 is provided at a distance of 6 to 35 kgf / inch, preferably 8 to 20 kgf / inch, in order to secure the strength required for non-opening and to maintain the folded state of the airbag cushion for a long time. (Measured in accordance with ASTM D 1683) of 33 kgf / inch.

As illustrated in FIG. 1, the delay unit 130 of the present invention may have an ultrasonic weld unit 131. That is, at least one delay unit 130 for delaying the opening of at least a part of the slit cut-off unit 120 is formed by performing ultrasonic welding on a part spaced from the slit cut-off unit 120 by a predetermined distance . For example, the ultrasonic welded portion 131 may be spaced apart from the slit cutout 120 by 0.5 to 2 cm toward the inflator.

According to the present invention, the opening time of the slit cut-off part 120 can be partially adjusted by forming the delay part 130 at a position corresponding to the cushion part requiring delayed expansion. Accordingly, the deployment time and the deployment angle of the airbag cushion can be adjusted as needed, and the passenger from a vehicle accident can be protected more safely.

When forming the delay unit 130, the ultrasonic welding conditions vary depending on the type of fabric of the airbag cushion cover 100. For example, in the case of an embodiment of the present invention in which the cover 100 for airbag cushion is manufactured using a PET nonwoven fabric having a thickness of 0.25 to 0.35 mm, the ultrasonic welding is performed at 5 to 15 kHz, preferably 7 to 13 kHz kHz, more preferably 9 to 11 kHz, for 0.5 to 3 seconds.

If the ultrasonic frequency is less than 5 kHz or the ultrasonic wave is applied for less than 0.5 sec, sufficient fusion of the fabric is not achieved. On the other hand, when the ultrasonic frequency exceeds 15 kHz or the ultrasonic wave is applied to the nonwoven fabric for more than 3 seconds, when the cover 100 is damaged during fusion or detachment (when the airbag cushion is deployed) or the airbag cushion is deployed, There is a fear that the fused portion 131 is not detached and the corresponding portion of the slit cutout 120 is not opened.

As other process conditions for the ultrasonic welding, for example, the pressing force may be set to 50 psi, and the hold before the ultrasonic wave start and the hold after the ultrasonic wave type may be set to 0.5 second, respectively.

The delay unit 130 of the present invention is a dotted line-type ultrasonic welding unit 131 having a dot shape of 2 to 5/100 mm, preferably 2 to 4/100 mm, ).

Each of the ultrasonic welded portions 131 has a length of 2 to 20 mm, preferably 3 to 19 mm, more preferably 4 to 18 mm and 1 to 10 mm, preferably 1.5 to 8 mm, And may have a width of 2 to 5 mm. However, depending on the folded shape of the airbag cushion, the ultrasonic fused portion 131 may have a length exceeding 20 mm.

Alternatively, the delay unit 130 may be formed of only one ultrasonic welding unit 131 as a solid line-type.

The delay unit 130 of the present invention may be formed in a straight shape, a curved shape, a zigzag shape, an arrowhead shape, a multi-line shape, or a mixture of two or more of them, depending on the shape of the slit cutout 120 of the airbag cushion cover 100. [ And the like.

The retarder 130 may have a bead strength (measured in accordance with ASTM D 1683) of 0.5 to 3 kgf / inch, preferably 0.7 to 2.7 kgf / inch, more preferably 1 to 2.5 kgf / inch. If the seam strength is less than 0.5 kgf / inch, opening of the corresponding portion of the slit cutout 120 can not be delayed as desired. On the other hand, if the seam strength exceeds 3 kgf / inch, there is a risk that the corresponding portion of the slit cutout 120 is not opened or opens too late.

The above-described airbag cushion cover 100 of the present invention has a front airbag for protecting a driver or a passenger from a frontal collision, a curtain formed when inflated and deployed, A curtain airbag that protects a head portion of a passenger, a side airbag that is mounted on a door or a side surface of a seat to protect a side portion of a driver or a passenger from a side collision, and the like.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. It is to be understood, however, that the embodiments described below are only for the understanding of the present invention, and the scope of the present invention is not limited to these embodiments.

Example 1

A plurality of slits 121 are formed in a line in the TD direction of the nonwoven fabric by using a blade cutter to a polyethylene terephthalate (PET) spunbonded nonwoven fabric (trade name: K2070NW, manufactured by Kolon Industries) having a thickness of 0.28 mm, Thereby forming a slit incision having bridges therebetween. The length of each slit was 1.5 cm, and the length of each bridge was 0.6 cm. Next, after the nonwoven fabric was folded, the non-opened portion of the folded nonwoven fabric was sewn with a polyester stitching yarn with a stitching number of 25/100 mm in a single-lock manner to form a sewing portion that was not opened when the airbag cushion was deployed.

A point linear delay portion including an ultrasonic welded portion of 4/100 mm was formed at a position 1 cm away from a part of the slit incision portion. Each ultrasonic weld has a width of 3 mm and a length of 5 mm and was formed by applying ultrasonic waves at a frequency of 10 kHz for 1 second. The pressing force was set to 50 psi, and the delay before the start of the ultrasonic wave and the hold after the ultrasonic wave type were set to 0.5 second, respectively.

Comparative Example 1

(Sewing length: 10 mm) was formed by using a polyester stitching yarn in place of forming an ultrasonic fused portion in a stitching method with a number of stitches of 20/100 mm in a single-lock manner, the same procedure as in Example 1 was carried out The airbag cushion cover was completed.

Comparative Example 2

Nylon 66 plain weave (yarn fineness: 420 denier, weaving density: 46 × 46 ea / inch) coated with RTV silicone rubber (Rhodia) at a coating weight of 30 g / m ² was used instead of PET nonwoven fabric, The cover for airbag cushion was completed in the same manner as in Example 1 except that the slits were formed in a line in the weft direction.

Comparative Example 3

(Sewing length: 10 mm) was stitched with a stitching machine of 20/100 mm in a single-lock system using a polyester sewing thread instead of forming an ultrasonic welded portion, the same procedure as in Comparative Example 2 was carried out The airbag cushion cover was completed.

The seam strengths of the retardation portions of the cover for airbag cushions of the Examples and Comparative Examples thus manufactured were respectively determined by the following methods, and the results are shown in Table 1 below.

* Seal strength of the delay part of the airbag cushion cover

The airbag cushion cover was cut to obtain a sample of 5 cm (width) x 10 cm (length). At this time, the cover for the airbag cushion was cut so that the sample included the delay part but not the slit incision part. On the other hand, the longitudinal direction of the samples of Example 1 and Comparative Example 1 using the PET nonwoven fabric was made to be the MD direction of the nonwoven fabric, and the longitudinal direction of the samples of Comparative Examples 2 and 3 using the nylon 66 pile fabric was made oblique.

The suture strength of the thus obtained sample was measured according to the ASTM D 1683 method. Specifically, the longitudinal ends of the samples were mounted on the upper and lower clamps of a universal material tester (Instron, UTM), respectively. At this time, the delay part of the cover was positioned in the middle of the upper and lower clamps. The upper clamp was moved upward while the lower clamp was fixed, and the strength at the time when the retarder was broken was measured.

Example 1 Comparative Example 1 Comparative Example 2 Comparative Example 3 Staple Strength (kgf / inch) 2.2 4 0.2 24

As can be seen from Table 1, when the airbag cushion cover is made of nylon 66 flat fabric in place of the PET nonwoven fabric, when the retardation portion is formed through ultrasonic welding (Comparative Example 2), the retardation portion is less than 0.5 kgf / It is impossible to delay the opening of the corresponding portion of the slit incision portion as much as desired. In the case of forming the retardation portion by sewing instead of the ultrasonic welding (Comparative Example 3), the retardation portion has a sealing strength much higher than 3 kgf / inch There is a large risk that the corresponding portion of the slit incision is not opened.

On the other hand, even when the cover for airbag cushion is manufactured using the PET nonwoven fabric, when the retardation portion is formed by sewing instead of ultrasonic welding (Comparative Example 1), the retardation portion has a sealing strength of more than 3 kgf / inch and the corresponding portion of the slit- There is a risk that it will not open or open too late.

100: cover for airbag cushion 110: sewing part
120: slit incision part 121: slit
122: bridge 130: delay unit
131: Ultrasonic fusing part

Claims (13)

A cover for an airbag cushion formed from a nonwoven fabric,
A seam area that is not open when the airbag cushion is deployed;
A slit-cutting area to be opened when the airbag cushion is deployed; And
At least one delaying area for delaying the opening of at least a portion of the slit incision,
Characterized in that the retarding portion has an ultrasonic welding portion.
Cover for airbag cushion. The method according to claim 1,
Wherein the delay unit has the ultrasonic fused portions of 2 to 5/100 mm spaced apart at a predetermined interval.
Cover for airbag cushion. 3. The method of claim 2,
Characterized in that the ultrasonic welds have a length of 2 to 20 mm and a width of 1 to 10 mm.
Cover for airbag cushion. The method according to claim 1,
Wherein the slit incision is located on the opposite side of the inflator,
Wherein the ultrasonic fused portion is spaced from the slit incision portion by 0.5 to 2 cm toward the inflator.
Cover for airbag cushion. The method according to claim 1,
Characterized in that the nonwoven fabric is formed of polyethylene terephthalate (PET).
Cover for airbag cushion. The method according to claim 1,
Characterized in that the sewing section includes at least one of nylon yarn, polyester yarn, polyolefin yarn, and aramid yarn as a sewing thread.
Cover for airbag cushion. The method according to claim 1,
Characterized in that the sewing portion has a stitch number of 10 to 35/100 mm.
Cover for airbag cushion. The method according to claim 1,
Wherein the sewing portion is formed in at least one of a single lock, a double lock, a single chain, and a double chain.
Cover for airbag cushion. The method according to claim 1,
Characterized in that the slit cutout has a plurality of slits and a plurality of bridges alternately arranged in a straight line.
Cover for airbag cushion. 10. The method of claim 9,
The length of each of the slits, which is parallel to the straight line, is 0.5 to 2 cm,
Characterized in that the length of each of the bridges, parallel to the straight line, is 0.5 to 1 cm.
Cover for airbag cushion. 11. The method of claim 10,
Wherein the sum of the lengths of the plurality of slits is 60 to 90% of the length of the slit cutout.
Cover for airbag cushion. Producing a nonwoven fabric;
Forming a plurality of slits in a row in the nonwoven fabric, thereby forming a slit incision having the slits and bridges therebetween;
Folding the nonwoven fabric along the slit incision;
Sewing at least a portion of the folded nonwoven fabric to form a sewn portion that is not open when the airbag cushion is deployed; And
And forming at least one delay portion for delaying opening of at least a part of the slit incision by performing ultrasonic welding on a portion spaced a predetermined distance from the slit incision portion.
A method of manufacturing a cover for an airbag cushion. 13. The method of claim 12,
The nonwoven fabric is formed of polyethylene terephthalate (PET)
Wherein the ultrasonic welding is performed by applying ultrasonic waves at a frequency of 5 to 15 kHz for 0.5 to 3 seconds.
A method of manufacturing a cover for an airbag cushion.

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