JP2003182512A - Seat belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a seat belt capable of reducing a load on the body of an occupant. <P>SOLUTION: A webbing 10 of the seat belt is formed by weaving warps 11 disposed in the extending direction and wefts 12. The warp 11 is formed by combining a first warp 11A made of PBT fiber and a second warp 11B made of PET fiber. Thus, the webbing 10 has characteristics of the PBT fiber and the PET fiber, can gradually increase elasticity, and can receive a large load over a wide range, so that the maximum value of the load acting to the occupant can be reduced and the load on the body of the occupant can be reduced. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a seat belt.

[0002]

2. Description of the Related Art An occupant is fixed to a seat with a seat belt for the purpose of safety in the event of an automobile collision. During the period from the collision of the automobile to the rest, the body of the occupant is restrained by directly receiving the load from the seat belt. For this reason, if the load acting from the seat belt is too small, the restraining force becomes insufficient, and it becomes impossible to protect the occupant. On the other hand, if the maximum value of the load applied from the seat belt becomes too large, it may cause an excessive load on the occupant. Therefore, it is necessary to reduce the maximum value of the load applied to the body.

Conventionally, there has been a webbing of a seat belt described in, for example, Japanese Patent Laid-Open No. 4-257336. This webbing is a combination of two types of fibers. As the first fiber, a fiber that receives a load from a region having a small elongation but has a small elongation is used, and as a second fiber, a small load is used in a region having a small elongation. Although it can only receive such a fiber, it uses fibers that suddenly receive a large load when a certain amount of elongation occurs. The elongation-load characteristics of this webbing are shown in Fig. 4, which shows that the first fiber is fractured after the load is mainly applied to the initial elongation region (between O and A in the figure) by the first fiber. (Point A in the figure), then the second
The fibers try to receive the load.

[0004]

However, in this webbing, after the first fiber ruptures at the point A, the webbing A up to the point B at which the load received by the second fiber increases.
The region between B and B is a region in which the webbing extends while receiving a constant load. For this reason, the restraint force does not change in the region between A and B, and therefore the acceleration and load of the occupant may not be sufficiently attenuated depending on the mode of collision. Then, the load that must be received in the latter half (between B and C in the figure) increases, and the burden on the occupant between B and C tends to be too large. In addition, there is also a problem in that shake of the body cannot be sufficiently suppressed due to insufficient restraint force. The present invention was completed in view of the above circumstances, and an object thereof is to provide a seat belt capable of reducing the burden on the body of an occupant.

[0005]

As a means for achieving the above object, the invention of claim 1 is a seat belt knitted with a warp in the extending direction of webbing, wherein the warp has a plurality of elastic moduluses different from each other. Combining different kinds of fibers, it has a plurality of regions exhibiting different elastic moduli with the increase of the elongation in the elongation direction of the webbing, and the elastic modulus gradually increases as it goes to the region of large elongation. The feature is that it is done.

According to a second aspect of the invention, in the first aspect, the warp comprises at least two types of yarns,
The property of at least one yarn has a plurality of regions exhibiting different elastic moduli as the elongation in the elongation direction of the webbing increases, and the elastic moduli gradually increase as the elongation increases. The remaining yarns are increased and changed, and the remaining yarns are characterized by adding their own strength to the strength of the at least one yarn in order to maintain the strength of the webbing.

The invention of claim 3 relates to claim 1 or claim 2.
The warp of PBT fiber and PET according to
It is characterized by being knitted in combination with fibers.

[0008]

According to the seat belt of the present invention, the webbing has a composite of the respective properties of the combined fibers, and when a tensile load is applied to the webbing, the elongation of the webbing is increased. Accordingly, the elastic modulus is increased stepwise. As a result, the load to be received can be continuously increased as the elongation of the webbing increases without having a region where the elastic modulus is lowered and only a constant load can be received in the process of extending the webbing as in the conventional case. Furthermore, during a vehicle collision, the webbing that has received a collision load expands comparatively significantly in the initial stage to suppress the load applied to the occupant, and then decreases the elongation and gradually increases the load. It is possible to prevent a large amount of compressive force on the occupant from being applied suddenly from the beginning of the collision. Therefore, the seat belt can reduce the maximum value of the load acting on the body of the occupant and reduce the burden on the body (the invention of claim 1).

Furthermore, the elastic modulus of the webbing can be increased stepwise with one of the two types of threads, and the strength of the entire webbing can be enhanced with the remaining threads (the invention of claim 2).

Further, by combining PBT fiber and PET fiber, the PBT fiber mainly receives the load at the initial stage of collision, and the PET fiber further receives the load when the elongation becomes large, so that the elastic modulus is changed stepwise. It becomes possible (the invention of claim 3).

[0011]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described with reference to FIGS. This embodiment is, for example, a seat belt used for protecting an occupant of an automobile, and the structure of the entire seat belt is similar to that of a known one. Although not shown, a so-called three-point type for restraining a waist and a chest is used. In addition to the above, it is a structure equipped with a pretensioner mechanism. Hereinafter, the webbing 10 used for the seat belt
Will be described.

FIG. 1 is an enlarged view showing the structure of the webbing 10. The webbing 10 has a warp yarn 11 arranged in its extending direction (vertical direction in FIG. 1) and a weft yarn arranged in a direction intersecting with the warp yarn 11. 12 is formed in a biased manner. The warp yarn 11 is knitted by combining two types of fibers, PBT (polybutylene terephthalate) fibers and PET (polyethylene terephthalate) fibers.

By the way, a desirable load characteristic for the webbing is that it receives a large load from an initial region where the elongation is small, the elastic modulus is gradually increased as the elongation increases, and the breaking strength is sufficiently provided. . Here, the PBT fiber and PET used in the present embodiment
The characteristics of the fiber will be briefly described. PET fiber is a fiber that has been conventionally used for webbing and has sufficient breaking strength, but the load that it receives in a region where elongation is small is small. On the other hand, although PBT fiber is inferior in breaking strength to PET fiber, PBT is
Can receive a larger load than ET fiber,
The elongation rate to break is large. In this embodiment, the PBT fiber and the PET fiber are combined in order to realize the ideal load characteristics for the webbing described above.

Warp yarn 11 of webbing 10 of this embodiment
Is the first warp yarn 11A made of the above PBT fiber and PE
It is configured by combining with a second warp yarn 11B made of T fiber. Then, as shown in FIG. 1, the webbing 10
Is knitted such that the first warp threads 11A and the second warp threads 11B are alternately arranged. PET fibers are used for the weft thread 12. Here, the first warp 11A has a fineness of 5
60 dtex, strength 6.1 cN / dtex, second warp 11B has fineness 1
The weft having a fineness of 1100 dtex and the strength of 6.7 cN / dtex was used.
In the present embodiment, the combined warp yarns 1 within the range where the webbing 10 restrains the body of the occupant.
No. 1 is combined so as not to break.

[Webbing Tensile Test] This webbing 1
FIG. 2 shows the result of a tensile test performed by applying a tensile load in the webbing extension direction (vertical direction in FIG. 1) with respect to 0 simple substance. When a tensile load is applied to the webbing 10, the load to be received continues to increase as the elongation increases, and the increase in the load temporarily decreases at point P where the elongation has advanced to some extent. Then, when a further tensile load is applied to the webbing 10 to increase the elongation, the load again increases.

Here, if the area from the state of zero elongation to the point P is area A and the area beyond the point P is area B,
Immediately before the point P, the first warp yarn 11A of the two warp yarns 11A and 11B exhibits a high degree of extension with respect to the load at this time, so that the increase in the load exerted by the webbing 10 is once moderated. In addition, when the region A and the region B are compared, the graphs show different changes, and the regions have different elastic moduli. Further, the increase rate of the load is larger in the region B than in the region A. That is, the elastic modulus of the webbing 10 of the present embodiment changes in a stepwise manner as the elongation increases. In this experiment, since the elongation of the webbing 10 is within the elastic range, when the tensile load is removed at the end of the region B, the elongation of the webbing 10 becomes zero. Also, this webbing 10 is J
26.7k required by IS standard D4604
Even when a tensile load of N was applied, it did not break.

[Collision Experiment] FIG. 3 shows the result of a collision experiment using the seat belt of this embodiment. In this collision test, a dummy imitating a human body is seated on a seat of an automobile, fixed with the seat belt of the present embodiment, and the automobile collides head-on with the wall surface. Then, the acceleration of the chest of the dummy at the time of this collision is measured. In addition, the thing of this embodiment is described as an example in FIG. A comparative example is a seat belt using a webbing in which both warp and weft are knitted with PET fiber, which are generally used at present, and other structures are experimental results of the same as that of the present embodiment. .

According to the experimental results, as shown in FIG.
In the initial range of 0 ms to 43 ms, the acceleration exceeds the comparative example. Since the acceleration is proportional to the load acting on the body, the load responsiveness in the region of initial elongation is improved. Furthermore, since the maximum value of acceleration is also reduced as compared with the comparative example, the maximum value of the load acting on the body can also be reduced. It is considered that this is because the kinetic energy absorbed in the initial region increased because the load received in the initial region increased.

As described above, according to this embodiment, PET is used.
Webbing 10 using fibers and PBT fibers for warp 11
To increase and change the elastic modulus in multiple steps, especially for PBT
A large load can be received at the initial stage of elongation based on the characteristics of the fiber, and there is no region that can only receive a constant load like the conventional example, and a large load can be received over a wide range. You can This reduces the maximum value of the load that acts on the occupant,
It has become possible to reduce the burden on the occupant's body. Further, in the present embodiment, since neither the first warp yarn 11A nor the second warp yarn 11B constituting the webbing 10 is broken, the strength of the webbing 10 as a whole can be improved, and the webbing 10 has PBT in all regions.
It is possible to exhibit characteristics that combine the characteristics of fibers and PET fibers.

<Other Embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments are also included in the technical scope of the present invention. In addition to the above, various modifications can be made without departing from the scope of the invention. (1) In the above embodiment, the PET fiber and the PBT fiber are combined with each other, but the elastic modulus may be increased stepwise by combining other fibers having different elastic moduli. Furthermore, the elastic modulus may be increased stepwise by combining three or more kinds of fibers in addition to the combination of two kinds of fibers as in the above embodiment.

[Brief description of drawings]

FIG. 1 is a partially enlarged view showing the structure of a webbing according to an embodiment of the present invention.

FIG. 2 Elongation of webbing-load curve

[Fig. 3] Acceleration / displacement graph of the human chest when a seat belt is used

FIG. 4 Elongation-load curve of conventional webbing

[Explanation of symbols]

10 ... Webbing 11A ... First warp 11B ... second warp 12 ... weft

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 3D018 BA03                 4L036 MA05 MA24 MA33 MA39 MA40                       PA33 PA46 UA07                 4L048 AA21 AA22 AA49 AB09 AC10                       BB01 CA02 DA26

Claims (3)

[Claims] 1. A seat belt knitted with warp yarns extending in the extending direction of the webbing, wherein the warp yarns are formed by combining a plurality of types of fibers having different elongation elastic moduli, and the warp yarns differ according to an increase in elongation in the extending direction of the webbing. A seatbelt having a plurality of regions exhibiting an elastic modulus, wherein the elastic modulus gradually increases as it goes to the region having a large elongation. 2. The warp comprises at least two types of threads, and the characteristics of at least one thread have a plurality of regions exhibiting different elastic moduli with an increase in elongation in the elongation direction of the webbing, The elastic modulus gradually increases as it goes to the region of high elongation, and the remaining yarns add their own strength to the strength of the at least one yarn in order to maintain the strength of the webbing. The seat belt according to claim 1, wherein the seat belt is a belt. 3. The warp yarn is knitted with a combination of PBT fiber and PET fiber.
Alternatively, the seat belt according to claim 2.