JPH0960676A - Shock relaxing material and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide shock relaxing material which protects passengers by absorbing shock energy and effectively damping the shock and is effective as bumper supporting member. SOLUTION: Shock relaxing material is made of fiber reinforced resin and composed by a hollow truncated cone part and a cylindrical part. The hollow truncated cone part 3 and the cylindrical part 4 are composed via an arc part 5 and arranged in series and integrally formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorbing material and a method for manufacturing the same, and more particularly to an automobile, an aircraft,
The present invention relates to a shock absorbing material which is attached to a vehicle such as a vehicle, effectively absorbs an impact received when the vehicle collides or falls, protects a passenger, and reduces damage to the vehicle, and a manufacturing method thereof.

[0002]

2. Description of the Related Art In a general automobile, bumpers are attached to the front and rear of a vehicle body to absorb the collision energy at the time of a collision and absorb the impact. Further, in order to further increase the absorbed energy, a supporting member for supporting the bumper body has conventionally been made of a material and structure capable of absorbing the collision energy.

Further, in an aircraft, a prior example in which an energy absorbing material made of a hard polyurethane foam is provided under a seat so as to reduce the impact at the time of an accidental landing due to an accidental failure, is disclosed in Japanese Patent Laid-Open No. 1-11942. It is disclosed in the official gazette. Further, Japanese Patent Laid-Open No. 6-123323 discloses an impact energy absorbing material made of a fiber-reinforced resin having a cylindrical shape with a bottom and a tapered tip and mixed with short fibers.

Particularly, as a relatively compact impact energy absorbing member having a supporting function that can be used as a supporting member for a bumper, a cylindrical member having a tapered tip or a hollow truncated cone member is used. Is considered,
Has been used.

[0005]

However, the energy absorbing material made of a hard polyurethane foam has a weak strength and is not suitable for a support member of a bumper or the like. Cylindrical members made of fiber reinforced resin have a peak load at the moment of collision, and the load only slightly increases after the load once decreases, but the peak load at the moment of collision has a very small effect on the human body. large.

Further, the cylindrical member is provided with a tapered portion in order to start breaking from the tip, so that the tip becomes weak and it is difficult to use it as a structural member such as a support member for a bumper. Further, in the hollow truncated cone-shaped member, the load peak at the moment of collision is hardly seen as in the cylindrical member, but the load gradually increases even after the load is saturated, and eventually a considerably high load is given to the human body. .

Further, the hollow truncated cone-shaped member fixes the thick diameter side to the pedestal, but when a load is applied to this portion, a force acts in the opening direction, which is a structural weak point, and it usually breaks from the small diameter side. However, sometimes the small-diameter side slightly breaks, but the fracture progresses from the large-diameter side to the opposite side, and the impact energy may not be absorbed as expected. .

The present invention was devised in view of the above conventional problems, and was made by effectively taking advantage of the advantages of the cylindrical member and the hollow truncated cone-shaped member as a shock absorber. There is no peak load at the moment of collision,
There is no load fluctuation after the load is saturated, the amount of energy absorbed per weight and volume of the member is large, and thus it is possible to effectively absorb impact energy and protect the human body of a vehicle occupant, and An object of the present invention is to provide an impact absorbing material having a sufficient supporting function for bumpers and the like and a method for producing the same.

[0009]

In order to achieve the above object, the present invention is characterized in that a hollow truncated cone-shaped portion and a hollow cylindrical portion are arranged in series and are integrally formed of a fiber reinforced resin. Is. Further, the gist of the present invention is that the hollow truncated cone-shaped portion and the cylindrical portion are arranged in series via the hollow arc-shaped portion and are integrally formed of fiber reinforced resin.

The fibers of the fiber-reinforced resin are arranged in two or more layers, the arrangement angle of which is 0 to 30 degrees with respect to the axial direction of the shock absorbing material, and at least one layer and the other layers are mutually separated. They are arranged in the opposite direction. Further, as the resin of the fiber reinforced resin which constitutes the impact absorbing material, a thermoplastic resin is preferable because it is easy to manufacture. As the thermoplastic resin, polyamide, polycarbonate, polypropylene, polyester, polyetherimide, polyetheretherketone and the like are preferable. Further, as the reinforcing fiber, glass fiber, carbon fiber, aromatic polyamide fiber and the like are preferable.

The present invention is constructed as described above, and a thermoplastic resin reinforced with fibers is molded into a shape and size similar to a product, the molded product is put in an outer mold made of metal, and the molded product is made of Teflon resin. Insert the mandrel consisting of, plasticize the thermoplastic resin by heating, crimp the molded product between the inner surface of the outer mold and the outer surface of the mandrel by thermal expansion of the mandrel, and then remove the outer mold and the mandrel after cooling. The product is a shock absorber.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows one embodiment of the shock absorbing material of the present invention, and FIG. 2 shows the shock absorbing material of the present invention. It is another embodiment. In FIG. 1, a hollow truncated cone part 1 and a hollow cylindrical part 2 are continuously formed, and the truncated cone part 1 and the cylindrical part 2 are made of a fiber-reinforced resin reinforced with fibers 6. There is.

In FIG. 2, a hollow truncated cone part 3, a cylindrical part 4 and an arcuate part 5 in which a hollow sphere is partially cut away.
The truncated cone portion 3 and the cylindrical portion 4 are arranged in series via the arcuate portion 5, and these are integrally formed.
The contour line 7 of the truncated cone portion 3 is in contact with the contour line 9 of the arcuate portion 5, and the contour line 8 of the cylindrical portion 4 is the contour line 9 of the arcuate portion 5.
Is in contact with The truncated cone portion 3, the cylindrical portion 4 and the arc portion 5 are made of fiber reinforced resin reinforced with fibers 6.

In both cases of FIG. 1 and FIG. 2, two layers of fibers 6 are arranged, the arrangement angle is 0 to 30 degrees with respect to the axial direction, and the two layers are arranged in mutually opposite directions. Has been done. In many cases, the fibers are preferably arranged at an angle of 0 to 30 degrees with respect to the circumferential direction in order to effectively absorb impact energy, but they may be arranged at other angles. The fiber 6 is not limited to two layers, and the fiber strength and the number of layers can be designed and selected to meet the required breaking strength of the impact relaxation material.

Further, the truncated cone portions 1 and 3 and the cylindrical portions 2 and 4 are
The axial dimension configuration, outer diameter and wall thickness of the shock absorber can also be selected according to the place of use and the required conditions of the impact absorbing material. 0.015 times the outer diameter or more, and in the cylindrical parts 2 and 4, 0.01 outer diameter
In many cases, it is desirable to be 5 times or more and 10 mm or less for both parts.

Next, the embodiment of FIG. 2 (example 1 of impact absorbing material), the hollow truncated cone 10 shown in FIG. 3 (example 2 of impact absorbing material) and the cylindrical body 11 shown in FIG. 4 (example The characteristics of Example 3) of the shock absorbing material will be described. The truncated cone 10
The cylindrical body 11 is a shock absorbing material that has been conventionally used, and is made of fiber reinforced resin. The frustoconical body 10 of FIG. 3 has a hollow frustoconical shape and a uniform thickness. The cylindrical body 11 of FIG. 4 has a cylindrical shape, one end 12 is tapered, and the wall thickness is uniform.

FIG. 5 shows the load characteristics of Example 1 of the shock absorbing material, FIG. 6 shows the load characteristics of Example 2 of the shock absorbing material, and FIG.
Is the load characteristics of Example 3 of the shock absorbing material. All of these figures show model test results. Also,
Table 1 shows a comparison of the characteristics of Example 1 of the above-described impact absorbing material to Example 3 of the impact absorbing material. Each of these figures shows a model load characteristic, and the load characteristic means a load response with respect to displacement or time when the impact relaxation material is compressed in the axial direction. The dynamic load characteristics are load characteristics at a test speed of approximately 1 m / sec or more, and the static load characteristics are load characteristics at a test speed of approximately 150 mm / sec or less.

[0018] Regarding static load characteristics, the impact mitigating materials of Examples 1 to 3 have no peak load at the moment of collision, but the impact mitigating material exhibits dynamic load characteristics at the time of actual collision of the vehicle. In the material example 2 (cylindrical body), a load peak occurs at the moment of collision, and there is a problem in protecting the human body of the occupant.

In Example 3 (frustroconical body) of the shock absorbing material, both static characteristics and dynamic characteristics gradually increase even after the saturated state after passing through the sharply increasing range of the load, and therefore, in this case as well, There is a problem in protecting the human body of the person. Furthermore, since the cross section of Example 3 (frustroconical body) of the shock absorbing material is inclined,
At the time of collision, a load also acts in the radial direction to push open the large-diameter end, and normally the fracture starts from the side with a smaller diameter and progresses gradually toward the larger-diameter side. When the small-diameter side slightly breaks, the large-diameter side reversely progresses, and the impact energy may not be absorbed as expected.

However, Example 1 of the shock absorbing material of the present invention, which is obtained by combining the cylindrical body and the truncated cone in series on the axis line through the arcuate portion, has the drawbacks of the shock absorbing material of Examples 2 and 3. It is possible to provide an impact absorbing material that has only the advantages described above. That is, in Example 1 of the shock absorbing material, there is no load peak at the moment of collision, and the load slightly increases even after reaching a saturated state after the load suddenly rises, but thereafter there is almost no change in the load, and the pedestal mounting side A stable structure can be formed because only the axial load is applied to the end of the.

Next, an embodiment of the manufacturing method will be described. A thermoplastic resin reinforced with fibers is cut into a substantially rectangular shape as shown in FIG. 8, and a notch 13 is provided on one edge. This is rounded and both edges of the notch 13 are put together to form a shape and dimensions similar to the product. A mandrel 14 made of Teflon resin and slightly smaller than the inner size of the product is manufactured. The molded product 15 is put into the metal outer molds 16 and 17, and the molded product 15
Insert the mandrel 14 inside. Outer mold 16,
17 is closed and heated to make the thermoplastic resin of the molded product 15 in a plastic state, and in that state, the Teflon mandrel 14
The molded product is pressed by the thermal expansion between the inner surface of the outer mold and the outer surface of the mandrel to obtain the shape and size of the product. Removal of the outer mold and mandrel produces the desired shock absorber.

Next, an embodiment of the present invention will be described. [Example] A fiber reinforced plastic (FRP) in which polyether ether ketone was used as a matrix and carbon fibers were arranged at an angle of ± 15 ° in the longitudinal direction.
An impact absorbing material was created with the shape and size shown in. Dynamic load characteristics were measured at a test speed of 6 m / sec using these buffer relaxation materials.

[0023] Test results of load-displacement and load-time dynamic load characteristics are shown in FIGS. 10 (A), 10 (B) (Example 1), and FIG.
(A), (B) (Comparative Example 1), FIGS. 12 (A), (B)
The results are shown in (Comparative Example 2). Thereby, the first embodiment
It can be seen that, in the dynamic characteristics of the impact absorbing material, the peak of the load is not recognized at the moment of impact, whereas the peak of the load appears at the moment of impact in Comparative Example 2.

[0024]

Since the present invention is configured as described above, there is no peak load at the moment of collision, there is little load fluctuation after the load is saturated, and the amount of energy absorbed per weight and volume of the member. Therefore, it is possible to effectively absorb the impact energy and effectively protect the human body of the occupant of the vehicle. Further, since it also has a supporting function such as a bumper, it can be used as a supporting material.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of an impact absorbing material of the present invention.

FIG. 2 is a vertical sectional view showing another embodiment of the impact absorbing material of the present invention.

FIG. 3 is a vertical cross-sectional view showing Example 2 of a model shock absorbing material.

FIG. 4 is a vertical sectional view showing Example 3 of a model shock absorbing material.

FIG. 5 is a graph showing the characteristics of a model shock absorber.

FIG. 6 is a graph showing the characteristics of Example 2 of a model shock absorbing material.

FIG. 7 is a graph showing the characteristics of Example 3 of the model shock absorbing material.

FIG. 8 is a plan view of a material cutting shape in the manufacturing method.

FIG. 9 is a vertical sectional view of a mold, a mandrel and a molded product in the manufacturing method.

10 (A) and 10 (B) are graphs showing test results of load-displacement and load-time dynamic load characteristics according to an example of the present invention.

11A and 11B are load-displacement of Comparative Example 1,
3 is a graph showing test results of load-time dynamic load characteristics.

12A and 12B are load-displacement of Comparative Example 2,
3 is a graph showing test results of load-time dynamic load characteristics.

[Explanation of symbols]

1, 3 Frustum-shaped part 7, 8, 9 Outer line 2, 4 Cylindrical part 14 Mandrel 5 Arc-shaped part 15 Molded product 6 Fiber 16, 17 Outer mold

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Claims (5)

[Claims] 1. A shock absorbing material, wherein a hollow truncated cone-shaped portion and a hollow cylindrical portion are arranged in series and are integrally formed of a fiber reinforced resin. 2. A shock absorbing material, characterized in that a hollow truncated cone-shaped portion and a cylindrical portion are arranged in series via a hollow arc-shaped portion and are integrally formed of a fiber reinforced resin. 3. The fibers of the fiber reinforced resin are arranged in two or more layers, and the arrangement angle is 0 to 30 degrees with respect to the axial direction of the shock absorbing material, and at least one layer and the other layers are respectively formed. Claim 1 or Claim 2 arranged in mutually opposite directions.
Impact absorbing material described in. 4. The shock absorbing material according to claim 1, wherein the resin of the fiber reinforced resin is a thermoplastic resin. 5. A thermoplastic resin reinforced with fibers is molded into a shape and size similar to a product, the molded product is placed in an outer mold made of metal, and a mandrel made of Teflon resin is inserted into the molded product and heated. To plasticize the thermoplastic resin and press-bond the molded product between the inner surface of the outer mold and the outer surface of the mandrel by thermal expansion of the mandrel, and after cooling, remove the outer mold and the mandrel to obtain a shock absorber product. The method for producing an impact absorbing material according to claim 4, wherein