KR20010021528A - Reduced stress inflatable band for vehicle occupant restraint system - Google Patents

Abstract

The present invention relates to an expandable band for a protective device that includes an expandable band that is formed to slow down the stress caused by the band fabric during expansion and secondary impact. This reduction in stress results in a fold in the pattern that most closely approximates the ideal radius of curvature of the band upon inflation, fastening the band to the seat belt using a small radius fixation, and keeping the center of the band unsewn. Is achieved by sewing the pleated portion of the band.

Description

REDUCED STRESS INFLATABLE BAND FOR VEHICLE OCCUPANT RESTRAINT SYSTEM}

Expandable band-type protective devices are increasingly recognized as being more advantageous than airbags and seat belts in automobiles in terms of safety and cost. An inflatable band-type protection device is usually installed in a three-position stationary seat belt device, like the airbag protection device, to inflate during a collision to protect the passenger. However, the inflatable bands remain in contact with the passenger prior to inflation in a manner similar to conventional seat belt arrangements, unlike airbags. This contact substantially eliminates time delays between inflation and passenger protection.

The airbag device decelerates the passenger by contacting the passenger's initial position and a predetermined position between the dashboard when the passenger rushes to the dashboard while the vehicle decelerates in a crash. In contrast, the inflatable band simultaneously tensions the belt and constrains the passenger in place, slowing it down to a speed close to the deceleration of the vehicle itself, ie to reduce the risk of injury to the passenger. The inflated band restrains the passenger's head, upper body and chest to prevent them from rushing into the vehicle during deceleration. The large contact area of the band distributes its deceleration more evenly on the part of the body that is less prone to injury than the head.

One of the problems associated with inflatable sheet-like bands is that in addition to the axial load caused by the impact of the body, high stresses occur at the connection area due to internal pressure. In the past, efforts have been made to use fabrics of greater volume and strength to increase the strength of the expandable band. This bulky fabric cannot become compact when sewn into a flat, thin shape for the "seat belt" function in the unexpanded state of the band, resulting in cutting and wear during deployment.

In view of the foregoing, there is a need for an expandable band that is designed to be more structurally effective to reduce the stresses and strains present in the band connection area, allowing for the use of lighter, softer fabrics.

The present invention relates to a vehicle passenger protection device. More specifically, the present invention relates to an inflatable band-shaped protective device in a shape capable of reducing stress and deformation of the inflatable band material.

1 is a cross-sectional view of a conventional inflatable band,

2 shows an ideal deployment state of the inflatable band,

3 is a diagram showing the actual track length in the deployed state of a conventional inflatable band,

4 is a partial cross-sectional view of an inflatable band according to the present invention,

5 is a cross-sectional view of the inflatable band according to the invention,

6 is a view showing a good sewing position of a conventional inflatable band,

7 is a view showing a good fixing shape according to another embodiment of the present invention,

8 is a detail view of a good fixing portion shape,

9 is a graph showing the folded thickness of the band according to an embodiment of the present invention.

The features and objects of the present invention will become more apparent from the following description and specific embodiments of the present invention. In particular, the features and objects of the invention will be realized by the constructions and combinations thereof described in the appended claims.

An advantage associated with the object of the present invention is to provide an inflatable band for a vehicle passenger protection device comprising a center plane and a plane of symmetry perpendicular to the center plane, as outlined herein and described through specific embodiments. A first inner pleat and a second inner pleat are also included, wherein the second inner pleat is further away from the plane of symmetry but closer to the center plane than the first inner pleat.

According to another aspect of the invention, there is provided an inflatable passenger protection device having an inflatable band of a plurality of pleated pairs of material. Each pair of pleats consists of an inner pleat and an outer pleat, which are spaced apart from the inner pleat by a material of an intra-pleat span having a first width. Adjacent corrugated pairs are interconnected by a material of inter-pleat span having a second width. The second width of the material of the middle pleat span is wider than the first width of the material of the inner-pleat span.

According to another aspect of the invention, an inflatable passenger protection comprising a plurality of inner pleats and outer pleats and a sewing pattern, the curvature of the sewing pattern being matched to the curvature of the inflated portion of the band in the connection region of the band Provide the device.

According to another aspect of the invention, an inflatable band for a passenger protection device having a first plurality of inner and outer folds lying on one side of the centerline and a second plurality of inner and outer folds lying on the other side of the centerline To provide. The inflatable band is folded in the pleats and secured to the belt by sewing, which is done through the band portion between the inner pleats and the outer pleats such that the area between the first and second inner pleats is not sewn. . The band may also use an adhesive instead of, or in combination with, sewing for fixation.

According to another aspect of the present invention, there is provided a vehicle passenger protection device comprising a belt and an inflatable band fixed to the belt in a concave fixed area having a radius equal to or less than the radius of curvature of the inflatable band upon inflation of the inflatable band. do.

The foregoing description and the following detailed description are all intended to be illustrative of the invention only, and not intended to be limiting, the scope of the invention being defined by the appended claims.

The invention will be described in detail through the preferred embodiments in conjunction with the accompanying drawings. The same reference numerals used throughout the drawings represent the same or similar components as much as possible.

Conventional expandable bands employ a simply folded structure to fold the band into a compact, flat shape resembling a seat belt as shown in FIG. The outer pleats 1-6 are stacked one on top of the other, and the inner pleats 11-15 are similarly stacked when the band is not inflated. In order to maintain the "seat belt" shape, the spans of the fabric that connect the outer pleats and inner pleats 11-15 by a predetermined distance, i.e., the distance f between the inner and outer pleats, are folded together and the entire band is a band It is sewed on a seat belt (not shown) extending through the interior of the.

Investigating the stresses generated during the initial expansion of the expandable band-shaped protection device, the inventors found that the corrugated structure of the band material had a significant effect on the stress distribution. Specifically, the inner folds are subjected to higher stress than other parts of the band material. The causes of such stress generation are illustrated in FIGS. 2 and 3.

The ideal expanded state of the band is shown in FIG. The ideal band would expand into the cylinder surrounding the belt 7 such that both the outer pleats 1-6 and the inner pleats 11-15 lie on the same circle with a radius of R.

In the case of a conventional band, the actual expanded state is shown in FIG. 3. The width f of the span of the fabric makes the development center point different, ie the center point of the outer pleats is R 'and the center point of the inner pleats is R, respectively. In this configuration, the inner pleats 11-15 are subjected to most of the load, while the outer pleats 1-6 do not play a significant role for the bearing of this load. Thus, the stresses and strains on the inner corrugated material are much higher than those on other parts of the band, and the webbing 7 of the seat belt to which the band is to be secured is subject to a large centerline load.

Figure 4 shows the corrugated shape of the expandable band according to one embodiment of the present invention. The expandable band material includes a plurality of pairs of pleats made up of inner pleats 11'-15 'and outer pleats 1'-6'. The outer pleats 1'-6 'are spaced apart from the inner pleats 11'-15' by the span material 21-25, 31-35. Inside each pair of pleats, the inner pleats are spaced apart by the inner-pleat span 21-25 from the outer pleats. Adjacent corrugated pairs are connected to each other by medium-pleat span materials 31-35. The width of the mid-pleat span material 31-35 is wider than the inner-pleat span material 21-25. As shown in FIG. 4, the pair of pleats consists of, for example, an outer pleat 1 ′ and an inner pleat 11 ′ spaced apart from each other by the inner-pleat span material 21. Adjacent pleat pairs consist of an outer pleat 2 ′ and an inner pleat 12 ′ spaced from each other by an inner-pleat span material 22. Two pairs of adjacent corrugations are connected to each other by an inner-pleat span material 31.

This pattern can also be formed symmetrically on the symmetry plane 8 and on the other side of the center plane 9 of the band. Although FIG. 4 shows a tuxedo pattern in which the pleats directly adjacent the belt 7 are smaller than other pleats, all of these pleats can generally be the same size.

5 shows the completed band. The inner folds are closer to the center plane 9 of the belt as they are farther from the plane of symmetry, creating a "tuxedo fold" shape. Moving the inner pleats outwards reduces the difference between the radially expanding positions of the inner pleats and the outer pleats. This difference tends to get smaller as it gets closer to the plane of symmetry. Similarly, the outer folds are closer to the center plane 9 of the belt the further away from the plane of symmetry 8. In addition, the clamping force is evenly distributed throughout the width of the webbing of the seat belt to lower the stress concentration.

Since the width of the band shown in FIG. 4 is about 2 inches, X is about 1 inch. Adjacent corrugations extend closer to the plane of symmetry 8 by a predetermined distance x, i.e. about 1/8 inch. The 1/8 inch overlap is repeated below the plane of symmetry. However, the distance x does not need to have the same distance, but may be of various lengths such as X1, X2, X3, X4, and the like. Expanding the band results in a less jagged appearance or a shape more approximating the expansion of the large volume of the cylinder than shown in FIG. 3, resulting in a more flexible flexion approximation. In other words, the tuxedo overlap shown in FIGS. 4 and 5 keeps the folded fabric at the outer periphery of the inflated cylinder with a very uniform length.

Preferably, the belt 7 is located in the plane of symmetry. The term "belt" as used herein refers broadly to the materials used to maintain the position of the band. For example, the belt extends completely through the center of the band, or a section of material that ends in the band, and can be fixed in place near the passenger's upper body (shoulder or head), or the band It may be similar to a conventional seat belt that anchors in place near the floor of a vehicle.

If the belt extends through the center of the inflatable band, the middle of the band folds in the pleats and the band between the inner pleats and the outer pleats 40 so that the area between the inner pleats closest to the center plane is not sealed. It can be secured to the belt by sewing 41 penetrating through the portion. This sewing shape can be used with a tuxedo overlap or with the conventional overlap shown in FIG. According to the tuxedo overlap, no sewing structure is present in the two layers of fabric area 42 between the innermost inner pleats 11 ', 11 ", 11"', 11 "". An adhesive may be used instead of or in combination with such sewing.

The inventors have found that by securing either of the ends of the inflatable band to the belt, it plays a significant role in the overall integrity of the inflatable band-shaped protection device. Conventional bands are secured by a flat anchoring site, or a "crown sewing pattern" using a convex sewing pattern, ie, sewing that bends away from the inflatable band. However, the inventors have found that this conventional fixation form enhances sewing and / or breakage of the band and / or belt in the fixation zone. This breakdown has been found to cause non-uniform stress in the fixed area since the actual use of the inflatable band is exposed to axial load from the passenger protection device. This axial load effectively reduces the radius of the expandable band to change the stress and strain at the anchoring site.

In order to improve the non-uniform stress occurring at the fixing site, the expansion band can be fixed to the belt in the concave fixing area shown in FIGS. 7 and 8. The radius of the curved fixed region is equal to or less than the radius of curvature R at the inflation of the inflatable band, such that the inflatable band is exposed when exposed to an axial load, such as a load caused by restraining the passenger. To compensate for the reduced radius. Here, the fixed area means the leading edge of the area where the band is fixed to the belt. This tip edge (i.e., the right side of the sewing area in Fig. 8) becomes more important because it supports most of the deformation in the fixed portion. The left side of the region is also supposed to have a predetermined radius of curvature, but shapes that do not are within the scope of the present invention. The radius of curvature of the concave fixed region may be a circle, parabola, or a radius corresponding to an arc of another curved shape that approximates the actual radius of the expanded band loaded axially during deployment.

The degree of difference between the radius of curvature of the fixed area and the radius of curvature of the expandable band is determined by the axial stress of the belt / band system. For example, in a structure where the belt is adapted to extend completely through the interior of the band, the belt will reinforce the band. Thus, the axial "stretching" of the resulting band is less than in a system where the belt does not extend through the band. Thus, the difference in radius of curvature can be greater in systems where the belt does not extend through the band, or in other structures that tend to be subjected to greater axial deformation.

The band may be fixed to the belt by various means by sewing, adhesives or a combination thereof, and the band may be fixed to the belt at both ends or at one end by applying the above structure.

The tuxedo overlap creates a non-uniform fabric thickness distribution over the width of the band as shown in FIG. 9 (shown without webbing of the seat belt), with the scale of FIG. 9 being adjustable by the fabric thickness. Typically, the number of layers accumulated is 12 layers. Such a profile can be cast or otherwise molded into a clip structure used to secure the belt to the band, or with a D-shaped belt routing clip similar to that used for conventional seat belts. Can be molded. This profile allows the pleats of the tuxedo overlap to be in place and deform into the shape shown in FIG. 9.

The invention will become more apparent through the following examples which represent the invention.

Example 1

In order to compare the stresses generated from the initial swelling, the inventors conducted a comparative analysis of the bands with the folded corrugated bands and the tuxedo superimposition shape by the finite element method. The analysis revealed the improvements that can be achieved by the tuxedo overlap pattern. This structure has a thickness similar to that of the conventional corrugated overlap pattern (pattern with seven layers formed on each side of the belt) at the center of the band.

The analytical model of the tuxedo overlap consists of 10,148 nodes and 10,128 membrane elements. Loads similar to those used for conventional corrugated band analysis were applied to the model and the results compared directly (20 psi in peak expansion).

All warp and fill results are presented as the capacity of the fabric and the fabric thickness as the color assignment factor. This was entered directly as a percentage of the fabric capacity in units commonly used for comparison of fabric strength, ie lb / in.

Analysis result of outer fabric

Shear forces for both tuxedo overlap and corrugated overlap were determined. The tuxedo overlap reduced the shear force from 41 lb / in to 29 lb / in, but more importantly, the area in the fabric where the shear force appeared. The maximum strain of the outer fabric was reduced from 10.8% to 7.7% in the tuxedo overlap, and the broad strain was reduced from 7-8% to 6-6.3%. The maximum fill stress distribution was found to be similarly reduced from 220 lb / in to 150 lb / in.

In the warp direction, there was a 42 lb / in reduction for the corrugated overlap and a 34 lb / in reduction for the tuxedo overlap.

Deformation in the upper layer of the fabric extended across the spherical section of the band toward both the corrugated and tuxedo overlaps towards the cylindrical portion of the structure. This portion of the fabric is most actively loaded by the secondary impact, since there are no wrinkles in these areas and the fabric is essentially taut only upon expansion. The tuxedo overlap is subject to 6% band fabric deformation, while the pleated overlap is subjected to a greater 8.8% band deformation. This is a potential failure site for dynamic loading, and has shown a significant improvement in tuxedo overlap.

In summary, in the tuxedo overlapping structure, the stress reduction in the center layer of the fabric outer layer was about 2/3 times that of the corrugated overlapping portion.

Analysis result of medial wrinkle

The tuxedo overlap reduced the peak fill load from 308 lb / in to 236 lb / in. The warp stress is lowered in this area because the wrinkles are not filled, and the stress value becomes meaningless. Deformation in the folds, like the fill, was reduced by 16.6% in the tuxedo overlap to 12.7%. More extensive results showed that 11% strain could be reduced to about 6-8% when tuxedo overlap was used.

Summarizing this analysis, the tuxedo overlap was found to reduce the stress of the inner fold by about one third.

It will be apparent to those skilled in the art that various modifications may be made to the structure of the expandable band and the protective device and the band and system described above without departing from the scope of the invention. For example, the number of pleats, span sections, and seams may differ from that of the illustrated embodiment.

Other embodiments of the invention may be readily estimated by those skilled in the art from the embodiments of the invention described above. The scope of the invention should not be limited to the embodiments described herein, but should be defined by the claims that follow.

Claims (17)

An inflatable band used in vehicle passenger protection, A center plane, a plane of symmetry perpendicular to the center plane, And a first inner pleat and a second inner pleat, wherein the second inner pleat is further away from the plane of symmetry but closer to the center plane than the first inner pleat. 2. The inflatable of claim 1, wherein the second outer pleats are further away from the plane of symmetry but closer to the center plane than the first outer pleats, including the first outer pleats and the second outer pleats. band. 2. The inflatable band of claim 1 comprising a belt disposed in the plane of symmetry. 4. The inflatable band of claim 3 wherein the inflatable band is folded in the pleats and secured to the belt by sewing, wherein the sewing is between the inner pleats and the outer pleats such that the area between the inner pleats closest to the center plane is not sewn. An inflatable band, characterized in that it is done through a band portion in the. 2. The inflatable band of claim 1, comprising a concave fixed region having a radius equal to or less than the radius of curvature of the inflatable band upon expansion. 2. The inflatable band of claim 1 comprising a concave fixed region having a radius less than the radius of curvature of the inflatable band upon inflation of the inflatable band. Inflatable vehicle passenger protection device, An expandable band of material having a plurality of pleat pairs, each pair of pleats consisting of an inner pleat and an outer pleat, wherein the outer pleat is spaced from the inner pleat by a material of an inner-pleat span having a first width Inflatable band, Adjacent pairs of corrugations interconnected by a material of the middle-pleat span having a second width, wherein the second width of the material of the middle-pleat span is wider than the first width of the material of the inner-pleat span An inflatable vehicle passenger protective device, characterized in that. An inflatable band used in vehicle passenger protection, A first plurality of inner pleats and outer pleats disposed on one side of the center line, A second plurality of inner pleats and outer pleats disposed on the other side of the center line, The inflatable band is folded in the pleats and secured to the belt by sewing, the sewing penetrating through a portion of the band between the inner pleats and the outer pleats such that the area between the first and second inner pleats is not sewn. An inflatable band, characterized in that it is done. With belt, A inflatable band having an expanded radius of curvature, said inflatable band being secured to said belt in a concave fixed area having a radius equal to or less than the radius of curvature of the inflatable band upon inflation; Protection device. 10. The band as recited in claim 9, wherein the concave fixed region has a radius smaller than the radius of curvature of the inflatable band upon expansion. 10. The vehicle passenger protection apparatus according to claim 9, wherein a sewing part is disposed in the fixed area. 10. The vehicle passenger protection apparatus according to claim 9, wherein an adhesive is disposed in the fixed area. 10. The vehicle passenger protection apparatus according to claim 9, wherein an adhesive and a sewing part are disposed in the fixing area. 10. The vehicle passenger protection device of claim 9, wherein the belt extends through an inflatable band. 11. The vehicle passenger protection device of claim 10, wherein the belt ends in an inflatable band. 10. A vehicular passenger protection device according to claim 9, comprising two securing areas, one at each end of the inflatable band. 10. A vehicular passenger protection device according to claim 9, wherein the radius of the fixed area coincides with the radius of curvature of the expansion of the loaded inflatable band.