JPH05221278A - Air bag and manufacture thereof - Google Patents

Abstract

PURPOSE:To provide an air bag of high reliability and also to avoid complication of a manufacturing equipment by using a cloth piece, not providing a position aligning sewing mark of the fellow cloth pieces of sewing together, to be stitched in a peripheral end line adjacent to a part of sewing together the cloth pieces. CONSTITUTION:An air bag 1 is constituted by sewing together an almost rectangular relatively long front surface cloth piece 2 and side surface cloth pieces 3, 4 in both sides of the cloth piece 2, to cut off a peripheral end edge 2a of the front surface cloth piece 2 and peripheral end edges 3a of the side surface cloth pieces 3, 4 in quite the same shape to a sewing together shape with no irregular shape of sewing together mark or the like. When the front surface cloth piece 2 and the side surface cloth piece 3 are sewed together, a sewing together starting part S1 of the side surface cloth piece 3 is aligned to a sewing together starting part D1 of the front surface cloth piece 2, to start stitching from this part. Thus by facilitating cutting off the cloth piece, the peripheral end edge of the cloth piece for aligning a sewing position can be easily arranged, and stabilization of a sewing margin can be realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airbag which protects an occupant from impact by expanding when a vehicle such as an automobile collides, and more particularly to an airbag formed by stitching a plurality of cloth pieces together and a method for manufacturing the same. It is a thing.

[0002]

2. Description of the Related Art In recent years, as a cushioning system for supporting a seat belt device for safely holding an occupant of a vehicle in a seat, a occupant's body, particularly a head and a chest, has a balloon-like (bag-like) shape at the time of a collision. An air bag that has been put into practical use has a cushioning stroke that is received by an air bag and then gradually releases the gas inside to suppress the impact force applied to the human body.

In the case of an emergency such as a vehicle collision, this type of air bag is designed to prevent reaction gases emitted from an inflator fixed to an instrument panel or other vehicle body fixing portion in a passenger seat bag, for example. It expands instantly due to pressure, and plays a crucial role in avoiding collision of the occupant with the vehicle body. By the way, since the above-mentioned airbag plays an extremely important role of protecting the occupant as described above from its original purpose, when it is inflated, its function is maximized not only in its strength but also in its shape. It is required to have a shape suitable for the place where it will be used. Therefore, in order to satisfy this requirement, firstly, the airbag is made of a fairly durable cloth (cloth piece), and then a plurality of cloth pieces are appropriately used to make the required complicated shape. A structure in which a desired shape is obtained by stitching is adopted.

Further, since the air bag is rapidly inflated by the gas generated by the inflator, its shock absorbing function is greatly influenced by the relationship between the generated gas and the air bag volume. That is, whether or not the volume of the airbag is the set value has a great influence on the impact absorbing action in relation to the gas generated by the inflator.

For these reasons, when sewing airbags, the positioning and seam allowance of the cloth pieces to be sewn at the time of sewing directly affect the shape and volume of the airbag when it is inflated, which affects the operating effect of the airbag. It had a big impact and needed a lot of attention. Therefore, even if a relatively simple piece of cloth, such as an airbag set in the center of the steering wheel, whose shape is substantially a circle, an ellipse, or an ellipse, is sewn, complete automatic sewing is not possible. It was extremely difficult.

Furthermore, the airbag on the passenger side is considerably more complicated than the airbag on the driver's side even in the shape of the airbag, and the size thereof is large, so that sewing is very difficult. That is, as shown in FIG. 8, for example, the passenger side airbag is required to have a shape that fits to the front side vehicle interior wall surface of the passenger seat when the airbag 40 is inflated. The shape is asymmetric in the direction. Further, since a large space is formed between the instrument panel 50 and the front windshield and the passenger seat, it is necessary to have a size that fills this space, and usually three or more sheets are required. An airbag is manufactured by stitching pieces of cloth together, and extremely accurate sewing is required for the reason described above in order to reliably exhibit the operation effect of the airbag.

Therefore, as shown in FIG.
Reference numeral 0 denotes a side cloth piece 30 (only one of which is shown) which is a pair of left and right cloths, and a front cloth piece 20 which is a cloth that directly contacts the human body
In the conventional case, the side cloth pieces 3 are provided at a plurality of locations on the edges of both the cloth pieces as a mark for aligning the side cloth piece 30 and the front cloth piece 20 which are upper and lower cloth pieces at the time of sewing.
0 is provided with suture marks 31, 32, and the front cloth piece 20 is provided with suture marks 21, 22, 23, 24 (21 is overlapped with 32) to ensure the accuracy of the suture. That is, while the operator is sewing the cloth pieces 20 and 30 having different shapes, the stitching marks are overlapped with the corresponding stitching marks so that, for example, the sewing work such as insertion is advanced. By paying attention,
It is formed for the purpose of minimizing an error in the stitching position deviation caused by the stretch or hang of the upper and lower cloth pieces during the sewing operation.

It seems that, as the stitching mark, an item in which a suitable mark is printed on a cloth piece is also adopted, but with such a mark form, it is used as a mark when the upper and lower cloth pieces are overlapped. Since the function is low, in many cases, as shown in FIG. 7, a protrusion-shaped mark or a notch-shaped form projecting at an edge of the cloth piece in an acute angle was adopted.

[0009]

As described above, in the conventional airbag manufacturing, a high precision is required for the sewing work, and thus the time and labor required for manufacturing the airbag are long. Further, the skill of the operator is required so that the quality does not vary due to the manual work. In particular, when the shape of the airbag becomes complicated, the size and shape of the cloth piece to be sewn greatly differ, so it is extremely difficult to sew without a sewn mark as in the past, and this sewn mark is always required. However, the current situation is that automation is difficult.

On the other hand, in the conventional sewing work of this type, for example, JP-A-56-20491 and JP-A-57-142289.
JP-A-59-14881, JP-A-59-67992, JP-A 64-2
As disclosed in Japanese Patent No. 687, etc., various sensors, cloth movement and cloth edge control mechanisms have been used so that even a less skilled worker can work. However, even when these sewing methods and devices are used, the device not only has the drawback of becoming very complicated, but especially when the sewing speed is increased, the seam allowance becomes narrow or wide. When stitching cloth pieces having curved contours such as the above-mentioned side cloth piece 30 and having protrusions such as stitch marks, as in the above-mentioned side cloth piece 30, when the stitches are misaligned It was the current situation that it occurred frequently.

For this reason, it is difficult to increase the productivity, and even if the shape of the airbag for the passenger seat is greatly different depending on the vehicle type, it is difficult to improve the productivity because of the poor productivity related to the total number of products. The manufacturing cost was very high. Due to this high cost, the vehicle models to which the airbag can be mounted are limited to high-end models. Therefore, it has been earnestly desired to solve the problem of high manufacturing cost.

In view of the above-mentioned circumstances, the object of the present invention is to provide an airbag with higher reliability than ever before, avoiding complication of manufacturing equipment (device), and manufacturing this airbag at a low price. It is to provide a manufacturing method that can be performed.

[0013]

The above-mentioned object of the present invention is to provide an air bag which is formed into a bag shape by stitching a plurality of cloth pieces together and protects an occupant from the impact of the collision by expanding when a vehicle collision occurs. An air bag characterized by being sewn using an outer peripheral edge of a cloth piece that is close to the sewn portion, in which the cloth piece to be sewn is not provided with a stitching mark for aligning the cloth pieces with each other. Can be achieved.

Further, the above object of the present invention is to sew each cloth piece for an air bag by sewing means while sandwiching both cloth pieces to be sewn and moving them in a predetermined direction.
At least immediately before the needle drop portion where the stitching is performed, the positional deviation of the outer peripheral edges of the cloth pieces near the stitched portion is detected by the detecting means, and the cloth piece is stitched based on the detection signal of the detecting means. By the cloth moving means for moving the cloth pieces in a direction substantially orthogonal to the direction, the outer peripheral edge portions of the both cloth pieces are sewn while being aligned, and each of the cloth pieces is provided with a stitching mark when the cloth pieces are sewn together. This can be achieved by a method for manufacturing an airbag, characterized in that sewing is performed using a material not formed on the outer peripheral edge.

[0015]

[Working] According to the present invention, by using a cloth piece having no uneven stitches on the outer peripheral edge of the sewing area, the outer peripheral edges of the upper and lower cloth pieces to be sewn can be easily aligned, and the seam allowance is stable. As a result, it is possible to provide an airbag which is easy to manufacture and whose bag shape is easily stabilized. Further, by sewing using a piece of cloth having no stitch marks such as irregularities on the outer peripheral edge, the position of the outer peripheral edge of the piece of cloth to be sewn can be easily detected even with a very simple sensor, Moreover, even when the piece of cloth is moved so as to be displaced based on the detection signal, it is possible to avoid the extra signal of the sensor due to the unevenness, so stable positioning can be performed without requiring agile movement operation, It was possible to use an automatic sewing device that can perform accurate sewing with stable seam allowances of base cloth pieces and that has a high sewing speed.

[0016]

EXAMPLE An example of the present invention will be described in detail below. 1 is a perspective view showing the inflated shape of the passenger airbag produced by the production method of the present invention. 2 is a plan view showing a state in which the side cloth piece and the front cloth piece are overlapped at the start of sewing in this embodiment, and FIG. 3 is a sectional view taken along line AA in FIG. Further, FIG. 4 is a front view showing a state where the cloth pieces are set in the sewing device, FIG. 5 is a plan view showing a state where the cloth pieces are set in the sewing device, and FIG. 6 is an edge aligning means for aligning the upper and lower cloth pieces. It is a principal part expansion perspective view of.

The passenger seat airbag 1 shown in FIG. 1 is constructed by stitching a relatively long front cloth piece 2 having a substantially rectangular shape and side cloth pieces 3, 4 having a substantially elliptical shape on both sides thereof. .. Then, the airbag 1 (a reinforcing cloth or the like is provided if necessary) which is formed into a bag shape by sewing three cloth pieces together is turned upside down, and the inflator or the like of the airbag device is attached thereto. It is attached to the attachment base 5, folded, and is covered with a lid (airbag cover) to be incorporated in the instrument panel.

Further, as shown in FIG. 2, the outer peripheral edge 2a of the front cloth piece 2 and the outer peripheral edge 3a of the side cloth pieces 3 and 4 do not have a concavo-convex shape such as a stitch mark as in the prior art, and they are sewn together. It is cut into exactly the same shape. Therefore,
Since there is no need to set the position where the stitching mark is formed, the work of cutting out each cloth piece from the cloth material becomes easy. In this front when sewing a cloth piece 2 and the side fabric piece 3, together with the start portion D ₁ stitching start portion S ₁ and the front cloth 2 stitched side fabric piece 3, to start sewing from this portion ..

Further, with reference to FIGS. 4 to 6, the essential parts of the sewing device 10 for sewing the airbag 1 shown in FIG. 1 will be described. This sewing device 10 is roughly classified into a mounting table 13 on which the side cloth piece 3 and the front cloth piece 2 which are overlapped are placed, and a sewing machine head 10a is arranged so as to stand upright from the mounting table 13, and the mounting table 13 is also arranged. A sensor 14 for detecting the positions of the outer peripheral edges 2a, 3a of the cloth pieces 2, 3 is provided near the surface of the sewing machine head 10a, and further, the cloth pieces 2, at the time of sewing, It is composed of a manipulator 15 which is a cloth moving means for correcting the position of 3.

The sensor 14 has, for example, a U-shape having upper and lower end pieces, and the wall surface upright with respect to the mounting table 13 can have a function of regulating the position of the edge of the cloth piece.
A photoelectric element (including a light emitting element and a light receiving element) is provided on the upper and lower end pieces of the upright wall surface, and the cloth pieces 2 and 3 are passed between the photoelectric elements to shift the position of the cloth piece. Can be detected. This misregistration detection is
For example, when the light reflectances of the front and back sides of both cloth pieces 2 and 3 are different, a pair of photoelectric elements are provided on the upper and lower end pieces, and by detecting the difference in the amount of reflected light from the front and back surfaces of the cloth piece and other than the cloth piece, It is possible to detect the deviation between the edges 2a and 3a of the cloth pieces 2 and 3. Further, with this configuration, it is possible to detect the position of both cloth pieces as a whole, that is, the position in a direction substantially orthogonal to the cloth feed direction. As the detection signal of the photoelectric element, for example, the strength of the electric signal generated by the light receiving element depending on the amount of light is used. The photoelectric element may have only the light emitting element and the light receiving element, but may have the configuration using the reflection plate 14a or the like as necessary as shown in the drawing.

Although the above-mentioned sensor 14 is fixed to the mounting table 13, it may be a movable type sensor that can be moved up and down or back and forth and left and right as needed. Furthermore,
In addition to this, this sensor is a mechanical switch such as a micro switch or a limit switch that directly touches the edge of the fabric, or a high frequency oscillation type, magnetic type, capacitance type, ultrasonic type, radio wave type, pneumatic type, etc. Various types of sensors can be used, such as a contact type proximity switch having a sensitive sensing function to a relatively insensitive sensor.

The manipulator 15 is, for example, a cloth piece 2,
3, a pair of upper and lower arms 17 are arranged so as to be positioned on the lower side and the upper side of the roller 3, and the rollers 16 which are rotatably driven are provided at the tip ends of the arms 17. Further, between the two arms 17, an intermediate plate 18 positioned so as to be inserted between the front cloth piece 2 and the side cloth piece 3.
Is provided.

In this manipulator 15, the front cloth piece 2 is sandwiched between the lower roller 16 and the intermediate plate 18, and the side cloth piece 3 is sandwiched between the upper roller 16 and the intermediate plate 18. In the embodiment, it is preferable that the two cloth pieces 2 and 3 are always pressed by an appropriate pressing force. The arm 17
Although not shown, it is configured to be able to move up and down (swing about a specific support shaft) by an appropriate fluid pressure cylinder, and it is possible to control workability and pressing force when setting a cloth piece. .. Then, based on the detection signal of the sensor 14, it is driven by an appropriate driving means such as a servo motor, and either the upper or lower roller 16 is rotated in a desired direction. Thereby, the cloth piece can be moved in a direction orthogonal to the cloth feed direction A at the time of sewing.

Further, since the manipulator 15 is controlled so that the upper and lower parts thereof are separately operated, although the curves of the outer peripheral edges 2a and 3a of the side cloth piece 3 and the front cloth piece 2 are greatly different, they are accurate. A suture can be guaranteed. The cloth piece feeding means is, for example, the sewing machine head 10a to the needle bar 11
With the well-known structure of the presser bar 19a provided on the support rod extending along the and the rack-shaped feed dog 19b provided on the mounting table 13, both cloth pieces 2 and 3 can be fed out in synchronization with the sewing. it can. Further, as an aid to the cloth feeding, for example, an air blow provided before and after the stitching area or a contact roller for contacting the cloth piece with an inclination in an appropriate direction and feeding the cloth piece in a specific direction is used for preliminary movement of the cloth piece. Alternatively, other suitable guide means can be used as necessary.

The stitching by the sewing device 10 having the above-mentioned structure will be described. Both cloth pieces 2 and 3 aligned as described above are placed on the mounting table 13 of the sewing apparatus 1 as shown in FIG. This corresponds to the sewing needle 12 (needle drop portion) to the above-mentioned stitching start portion S _1, and a small region downstream from the stitching start portion S ₁ (from the position of the needle drop portion to the manipulator). The outer peripheral edges 2a and 3a of the portion (1) are aligned with each other and set on the sewing device 10.

The two cloth pieces 2 and 3 thus set are automatically fed in the left direction (the direction of arrow A) in the figure by the cloth feeding means simultaneously with the driving of the needle bar 11, that is, the sewing, and the predetermined sewing is performed. Done. In the middle of this stitching, for example, the side cloth piece 3 and the front cloth piece 2 have their outer peripheral edges 3a as shown in FIG.
And 2a are misaligned (positional deviation), the roller 16 of the manipulator 15 rotates in a predetermined direction (direction of arrow X). As a result, the side cloth piece 3 is moved by being dragged by the roller 16 (direction of arrow C), and the outer peripheral edge 3a can be aligned with the other outer peripheral edge 2a. The operation of the manipulator 15 is quickly performed by the sensor 14.

When the automatic sewing is performed as described above, since the outer peripheral edges 2a and 3a of the two cloth pieces 2 and 3 are not provided with unevenness as a stitching mark as in the prior art, the sensor 14 is used. The outer peripheral edges 2a and 3a can be accurately detected,
It is possible to avoid the generation of an erroneous signal of the sensor 14 due to the unevenness, and the outer peripheral edges 2a and 3a by the manipulator 15 can be avoided.
Since the position can be stably and reliably aligned, it is possible to perform accurate alignment stitching without variations in the seam allowance and deviation of the stitches, and it is possible to perform high-quality sewing.

Further, the operator only sets the outer peripheral edges 2a and 3a of the start portions of the two cloth pieces 2 and 3 on the apparatus 10 and sets them on the apparatus 10, and thereafter, the outer peripheral edges are detected and the sewing margin is stable. Therefore, it is possible to perform stable and extremely accurate sewing work for keeping the bag shape and the bag volume at the set values. Incidentally, it is possible to appropriately set various other modes such as partial clearance required due to the difference in shape of the upper and lower cloth pieces, the pressure of the manipulator against the cloth piece, and the sewing speed.

In this sewing operation, the sewing starts from the sewing start portion S ₁ to the sewing end portion S ₂ at a predetermined speed, and the sewing on one side is completed. After that, for the sewing on the opposite side, for example, the D ₄ portion of the front cloth piece 2 is used as a stitching start portion, and the side surface cloth pieces on the opposite side are combined to perform a predetermined sewing in the direction of the stitching end portion D ₃ . In addition, the order of the regular sewing of the stitching start portion and the stitching end portion described above can be reversed as a matter of course.

The airbag 1 sewn in this way
Next, the fixing portions 2b and 3b, which are subsequently fixed to the mounting base 5, are sewn and subjected to a predetermined process, and then turned inside out, that is, as shown in FIG. The seam corner 6 of 1 is the seam allowance 7
Is fixed to the mounting base 5 in a state of being inward of the bag, and is folded and stored.

Although the above embodiments have been described with respect to the passenger airbag, the present invention is not limited to this and can be applied to various airbags. The apparatus for carrying out the manufacturing method of the present invention is not limited to the apparatus shown in FIGS. 4 to 6. For example, the manipulator has a structure in which a plurality of arms having one arm are provided on the front and back of the mounting table. Various structures can be adopted, and the structure of the cloth piece feeding structure, the sensor, etc. can be variously modified.

[0032]

As described above, according to the present invention, the cloth piece, which is a constituent member of the airbag, is not provided with accurate stitching marks for positioning, so that the cloth piece can be easily cut. In addition, the outer peripheral edge of the cloth piece for aligning the stitching position can be easily aligned and the seam allowance can be stabilized. Therefore, the bag shape is stable and the productivity is high simply by aligning the edge. An airbag suitable for sewing can be provided. Further, according to the manufacturing method of the present invention,
Since the outer peripheral edges of both cloth pieces to be sewn together are not uneven, it is possible to detect the positions of both edges easily, and a relatively simple sensor can be sufficiently used. By means of the means, it is easy to keep the seam allowance constant, extremely accurate automatic sewing can be performed, and it is possible to perform automatic sewing by machine sewing of the outer peripheral portions of the front cloth and the side cloth having different shapes and sizes. Therefore, it is possible to perform an accurate sewing operation of an airbag having a complicated shape in an extremely short time, and it is possible to improve the quality of the airbag, significantly improve the productivity, and reduce the cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing a state where an airbag of the present invention is inflated.

FIG. 2 is a plan view showing a combined state of the side cloth piece and the front cloth piece at the start of sewing in one embodiment of the present invention.

3 is a cross-sectional view taken along the line AA in FIG.

FIG. 4 is a front view showing a state in which a piece of cloth is set in the sewing device that carries out the method of the present invention.

FIG. 5 is a plan view showing a state in which a piece of cloth is set in the sewing device that carries out the method of the present invention.

FIG. 6 is a perspective view of a main part of a manipulator of a device that carries out the sewing method of the present invention.

FIG. 7 is a plan view showing a state in which a side cloth piece and a front cloth piece are superimposed on each other in a conventional passenger airbag.

FIG. 8 is a perspective view of a main part in the vehicle showing a state where the passenger airbag is inflated.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Airbag 2 Front cloth piece 2a, 3a Outer peripheral edge 3, 4 Side cloth piece 5 Attachment base 6 Stitching corner 7 Sewing allowance 10 Sewing machine 10a Sewing machine head 11 Needle bar 12 Sewing needle 13 Placement table 14 Sensor 15 Manipulator 16 Roller 17 Arm 18 Intermediate plate 19a Presser foot 19b Feeding tooth S ₁ Side cloth piece sewn start portion S ₂ Side cloth piece sewn end portion D ₁ , D ₄ Front cloth piece sewn start portion D ₂ , D ₃ Front cloth piece sewn End

Claims (2)

[Claims] 1. An airbag, which is formed into a bag shape by stitching a plurality of cloth pieces together and protects an occupant from the impact of the collision by inflating at the time of a vehicle collision, the outer peripheral edge of the cloth piece approaching the sewn portion. The airbag is sewn using a cloth piece which is not provided with a stitching mark for aligning the cloth pieces with each other. 2. When sewn together each piece of cloth for an airbag by means of sewing means, both pieces of cloth to be sewn are sandwiched and moved while moving in a predetermined direction, and at least immediately before the needle drop portion where this sewing is performed. A cloth for detecting the positional deviation of the outer peripheral edges of the two cloth pieces in the vicinity of the stitching portion by the detecting means, and moving the cloth pieces in a direction substantially orthogonal to the stitching direction based on the detection signal of the detecting means. By means of transportation
The sewing is performed while aligning the outer peripheral edges of the both cloth pieces, and the sewing is performed on each of the cloth pieces by using stitch marks that are not formed on the outer peripheral edges when sewing the cloth pieces together. A method for producing a characteristic airbag.