JPH07314467A - Structure - Google Patents

Abstract

PURPOSE:To provide a lightweight and high-strength structure by specifying the dimensional ratio of a sectional shape forming a closed space. CONSTITUTION:A structure is constituted, so that the closed space is formed by a section which is cut by a plane vertical to a face receiving bending load and the material forming the closed space is comprised of thermoplastic resin 1 containing continuous fiber oriented in one direction at 40-80wt.%. The distance between the neutral axis of the figure of a sectional shape forming the closed space and a face receiving load is defined as E1, and the distance between the neutral axis and the face in the side opposite to the face receiving load is defined as E2. When the sectional shape is same in each part of the structure, E2/E1 is 1.5-2.4. Further, when the sectional shape differs in each part of the structure, the mean value of the maximum value and the minimum value of E2/E1 is 1.5-2.4. Thereby strength of the material is effectively shown and the structure is made more lightweight and resistance to impact is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lightweight structure having excellent mechanical strength, and more particularly to a structure for a bumper beam.

[0002]

2. Description of the Related Art Conventionally, a bumper beam made of metal has been used in an automobile for the purpose of cushioning a shock at the time of a collision. These bumper beams are heavy and poor in fuel efficiency because a relatively thick metal is used to prevent damage to the vehicle body in the event of an automobile collision. The one using fiber reinforced plastic to solve this drawback has recently been put on the market. Among them, it is said that a manufacturing method in which a plate-shaped material in which a polypropylene resin is impregnated in a mat-shaped glass fiber is stamped to form a bumper beam has high productivity and is promising.

However, in stamping molding using this plate-shaped material, the mat-shaped reinforcing fibers do not completely follow the flow of the resin, so that there is a portion with few fibers depending on the shape, and the strength of that portion becomes weak. For this reason,
It has been pointed out that large shocks are likely to cause large deformation and breakage, and when used as a bumper beam, there is a problem with reliability compared to metal materials. If the parts are designed based on the weak parts, the other parts will be of excessive quality, the weight of the parts will increase, and the cost will increase, which is not rational. Such a molding material is 100k
It has been pointed out that there is a problem that molding at a high pressure of g / cm ² or more is required, and the burden of equipment costs such as a mold and a molding machine becomes large. In addition, ordinary polypropylene resin has a low flexural modulus, and when a resin having such a low flexural modulus is used, the bumper beam is inferior in the ability to propagate the impact applied to the structure of the bumper beam. It is pointed out that this is a major problem because it causes a compressive buckling failure locally and is used as a structural material because of its small impact energy absorption capacity.

Further, generally, a fiber-reinforced resin composite material has a compressive strength weaker than a tensile strength, unlike a metal material.
Therefore, when the bumper backup beam made of a metal material has the same shape, that is, when the cross-sectional shape when cut along a plane perpendicular to the surface subject to bending load does not form a closed space, that is, when it is open. If it is a cross-sectional shape,
The material's compressive strength cannot withstand the compressive load applied to the surface subjected to the impact load, and it ruptures. The phenomenon that it does not occur is observed, and the material strength cannot be effectively expressed.

[0005]

SUMMARY OF THE INVENTION In view of the above problems, the present invention is capable of molding at a low pressure with a low facility cost burden, has no uneven distribution of fibers which causes strength unevenness, and has an excellent load transmission capability. It is an object of the present invention to provide a bumper beam structure having high rigidity and high impact energy absorption capability.

[0006]

[Means for Solving the Problems] That is, the present inventors
Thermoplastic resin containing continuous fibers in which a cross-section cut by a plane perpendicular to a surface receiving a bending load forms a closed space, and the material forming the closed space contains unidirectionally arranged continuous fibers having a weight content of 40 to 80%. When the distance between the neutral axis of the cross-sectional shape forming the closed space and the surface receiving the load is E1, and the distance between the neutral axis and the surface opposite to the surface receiving the load is E2,
When the cross-sectional shape is the same in each part of the structure, E2 / E1 is 1.
5 to 2.4, and when the cross-sectional shape is different in each part of the structure, the average value of the maximum value and the minimum value of E2 / E1 is 1.5 to
It was found that the objective can be achieved by setting 2.4.

When a structure such as a bumper beam is subjected to a bending load, the load-bearing surface is subject to compression, while the face opposite the load-bearing surface is subject to tension. At this time, there is a surface which is neither compressed nor stretched between these two surfaces. This plane is called the neutral plane. There is a line that corresponds to the neutral plane when cut in a plane perpendicular to the plane that receives the bending load. This line is called the neutral axis. Therefore, when viewed from a plane cut by a plane perpendicular to the plane receiving this bending load, when a bending load is applied, a compressive load is applied from the surface receiving the bending load to the neutral axis, and the bending from the neutral axis A tensile load is applied to the surface opposite to the surface receiving the load.

If the cross section cut by a plane perpendicular to the surface receiving the bending load has a cross sectional shape in which the compression side and the tension side are fractured at the same time, the material strength can be effectively exhibited, the weight is lighter and the impact resistance is higher. It is possible to improve the sex. For that purpose, the shape of the cross section, when cut along a plane perpendicular to the surface that receives the bending load, forms a closed space, and the surface closer to the neutral axis of the cross section may be the load surface. preferable. In particular, when the distance between the neutral axis of the cross-sectional shape forming the closed space and the surface receiving the load is E1 and the distance between the neutral axis and the surface opposite to the surface receiving the load is E2, E
2 / E1 is E2 / when the cross-sectional shape is the same in each part of the structure
E1 is preferably 1.5 to 2.4, and more preferably 2.0 to 2.4. Further, when the cross-sectional shape is different in each part of the structure, the average value of the maximum value and the minimum value of E2 / E1 is 1.5 to
It is preferably 2.4, and more preferably 2.0 to 2.4. When E2 / E1 is less than 1.5, the compression side is broken, whereas the tensile side is not broken, and E2 / E1 is 2.
When it exceeds 4, the material does not break on the compression side but on the tensile side, and the strength of the material is not used up effectively. E2 / E1
Is 1.5 to 2.4, the tensile side and the compression side are fractured almost simultaneously, and the material strength can be effectively used.

In order to form a closed cross-sectional shape, it is desirable that fusion bonding of a thermoplastic resin in a molten state can be carried out at a low pressure without using a material such as an adhesive at the joint portion. As the above, a laminated body of thermoplastic resin plates containing continuous fibers arranged in one direction, that is, a prepreg is effective.

The thermoplastic resin containing continuous fibers arranged in one direction is preferably a resin having a high flexural modulus, and more preferably a polypropylene resin having a high flexural modulus. The polypropylene resin having a high flexural modulus is a homopolymer of propylene, a copolymer of propylene and an α-olefin such as ethylene or butene, and may be any one having crystallinity. The flexural modulus of the thermoplastic resin is 120 to 350 kg / m when injection-molded under the appropriate molding conditions.
m ^{2 is} good, and 150 to 300 kg / mm ² is more preferable. If the bending elastic modulus is less than 120 kg / mm ² , the load received by the structure does not propagate to the entire structure, and only the part to which the load is applied is locally deformed, and the load bearing performance is deteriorated. On the other hand, if it exceeds 350 kg / mm ² , the resin becomes brittle and the durability against impact load decreases.

The method for producing a thermoplastic resin having a high flexural modulus is not particularly limited, but as an example, titanium tetrachloride is reduced with diethyl aluminum chloride, then treated with diisoamyl ether, and further treated with titanium tetrachloride. Polymerized using a combination catalyst system consisting of a titanium trichloride composition catalyst, an organoaluminum compound (eg, diethylaluminum chloride), and optionally a third component (eg, ether, ester, phosphite compound, etc.). To be Further, if necessary, a crystal nucleating agent (eg, sorbitol derivative, diallyl phosphate metal salt, etc.) may be added.

A grafted thermoplastic resin can be used to improve the adhesion between the continuous fibers arranged in one direction and the thermoplastic resin. Grafted thermoplastic resin refers to a crystalline polypropylene resin obtained by graft-polymerizing a radically polymerizable unsaturated compound with an organic peroxide catalyst in a hydrocarbon solvent and adding the grafted polypropylene to the thermoplastic resin. 0.005 to 3 parts by weight is preferable, and the addition amount of 0.2 to 2
More preferably parts by weight. When the addition amount is 0.005 parts by weight or less, the adhesion to the glass fiber is insufficient and the strength is not exhibited, and when it is 3 parts by weight or more, the resin becomes brittle and the impact resistance decreases.

Examples of the radically polymerizable unsaturated compound to be grafted include maleic anhydride, itaconic anhydride, citraconic anhydride, glutaconic anhydride and the like. Maleic anhydride is usually grafted to polypropylene in an amount of 2 to 10 parts by weight. The flexural modulus of the grafted polypropylene resin is preferably 120-350 kg / mm ² .
50 to 300 kg / mm ² is more preferable.

The continuous fibers arranged in one direction are preferably glass fibers. When arranging continuous fibers in one direction, a monofilament having a thickness of 3 to 25 μm is usually 200 to 1200
A predetermined number of yarns or rovings having 0 bundles are arranged in one direction to impregnate them with the thermoplastic resin. The glass fiber used is one that is treated with a silane-based, titanate-based, or zirconium-based coupling agent to improve the adhesion to the resin. In the case of glass fiber, it is necessary to select a coupling agent that improves the adhesion to the polypropylene resin.

Examples of such coupling agents include γ-aminopropyl-trimethoxysilane and N-β.
-(Aminoethyl) -γ-aminopropyl-trimethoxysilane, β- (3,4-epoxycyclohexyl) ethyl-trimethoxysilane, γ-glycidoxy-propyltrimethoxysilane, γ-aminopropyl-triethoxysilane, vinyl Trimethoxysilane, vinyl-tris- (2-methoxyethoxy) silane, γ-methacryloxy-propyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropylmethyldimethoxysilane, γ-chloropropylmethyldimethoxysilane, γ-
Mercaptopropyltrimethoxysilane, p-aminophenyltriethoxysilane, isopropyl-triisostearoyl titanate, isopropyl tridodecylbenzene sulfonyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, tetraoctyl bis (ditridecyl phosphite) titanate,
Tetra (2,2-diallyloxymethyl-1-butyl)
Bis (ditridecyl phosphite) oxyacetate titanate, bis (dioctyl pyrophosphate)
Examples include ethylene titanate.

The method of applying the coupling agent to the fiber surface is as follows. That is, a liquid in which 0.1 to 3% by weight of the coupling agent is dissolved on the fiber surface is completely wetted by means such as dipping or spray coating. The fiber containing the coupling agent solution is dried at 60 to 120 ° C to allow the coupling agent to react with the surface of the fiber. The drying time is sufficient to evaporate the solvent, which is about 15 to 20 minutes. The solvent that dissolves the coupling agent, depending on the surface treatment agent used,
There are cases where an aqueous solution adjusted to a pH of about 2.0 to 12.0 is used and cases where an organic solvent such as ethanol, tolueneacetone, xylene, etc. is used alone or in a mixture.

There are various means for impregnating continuous fibers arranged in one direction with a thermoplastic resin, but the most general method is as follows. One is a method of dissolving a resin soluble in a solvent, impregnating the reinforcing fiber with the resin, and then removing the solvent while defoaming. The other is a method in which a resin is heated and melted to impregnate reinforcing fibers, followed by defoaming and cooling. The thermoplastic resin containing continuous fibers arranged in one direction manufactured in this manner has excellent adhesion between the fibers and the thermoplastic resin, and the fiber content rate is 30%.
The thickness can be changed according to the requirement from ~ 90%, and the thickness is 0.
It can be manufactured as thin as 1 to 1.0 mm.

If a core material is placed in the space of the closed cross section, local breakage of the portion to which an impact load is applied is prevented, and the impact resistance of the structure is further improved. A thermoplastic resin foam is preferable as the core material. As the thermoplastic resin foam, a polypropylene foam having an expansion ratio of 2 to 50 times,
Alternatively, a polystyrene foam having a polypropylene foam as an outer layer may be used, but the invention is not limited thereto.

The impact load of the structure can be further improved by integrating the thermoplastic resin foam with the thermoplastic resin containing fibers. In order to integrate the prepreg and the thermoplastic resin foam, the thermoplastic resin of the prepreg is in a molten state and one or more laminated bodies are superposed on and closely adhered to the surface of the foamed resin body having a desired outer shape to form a laminated body. By melting the surface of the foamed resin body with the heat of the machine and fusing the laminate and the thermoplastic resin foam to each other, the prepreg laminate and the thermoplastic resin foam can be integrated without using an adhesive. Can be turned into. The thermoplastic resin foam does not necessarily have to be filled in the entire space of the closed cross section, and there is no problem even if the foam is not provided in a place where the load bearing rate is low. The integration is performed under a low pressure of 3 kg / cm ² or less while the thermoplastic resin plate containing fibers is in a molten state. When the pressure is 3 kg / cm ² or more, the resin of the thermoplastic resin plate containing the fibers flows, and the arrangement of the fibers is disturbed, which causes a decrease in strength. Further, the resin foam is crushed to cause a structural failure. It causes problems such as a decrease in strength.

When the bumper beam receives an impact load, the bumper beam is deformed toward the vehicle body to buffer the impact energy and protect the vehicle body and passengers inside the vehicle. The greater the amount of deformation toward the vehicle body, the greater the amount of energy absorbed and the greater the safety. Therefore, it is preferable that the load-bearing surface of the bumper beam bulges in an arcuate shape in the load-bearing direction. If the surface that receives the impact load is destroyed first, the impact load is directly applied to the vehicle body, which is a safety issue. As a countermeasure, it is preferable to partially increase the plate thickness of the portion that first receives the load as compared with the other portions in order to improve safety.
In addition, using a foam that has a lower expansion ratio on the side that receives the impact load than the surface that does not receive the load is an effective means for propagating the load to the entire bumper beam and improving load bearing performance. .

The present invention will be described in detail below with reference to the drawings. FIG. 1 shows the shape of the bumper beam. 10
A is a conventional bumper beam, whose cross section is not a closed cross section structure. 10B and FIG. 2 of FIG. 1 show examples of the sectional shape of the bumper beam structure obtained by the manufacturing method according to the present invention, but the shape is not necessarily limited to this.

FIG. 3 shows an example of an external perspective view of a bumper beam structure obtained by the manufacturing method according to the present invention. However, the shape of the cross section is not necessarily limited to this shape. Reference numeral 30A denotes a 1.4 m long straight bumper beam structure, and 30B denotes a 1.4 m long bumper beam structure, so that a load is applied so as to be convex toward a surface subjected to an impact load. The arch-shaped bumper beam structure with curvature on both the face side and the load face side, 30C has a curvature of 1.4 m in length so that it is convex to the impact load face side. The facing surface on the load surface side shows a structure for a bumper beam which is straight. By attaching the arch in this way, it is possible to increase the rigidity and reduce the flexure at the time of breaking. Reference numeral 30D is a straight beam added with a portion having an increased plate thickness in the central portion thereof, and is effective in improving the rigidity and load bearing performance of the bumper beam structure.

FIG. 4 shows details of the sectional shape of the bumper beam structure according to the present invention. Reference numeral 1 indicates a prepreg laminate, and 2 indicates a foam. The respective laminates are heat-sealed to each other in a state of being preheated to the melting temperature of the resin or higher, and are integrated without using an adhesive. The foam and the laminated body are heated by the heat of the laminated body preheated to the melting temperature of the resin constituting the laminated body, the surface resin of the foamed body is melted and mixed with the resin on the surface of the laminated body to be integrated, and then cooled. So it is firmly bonded without using an adhesive.

FIG. 5 is a schematic view showing a method for manufacturing a bumper beam structure according to the present invention. First, the prepreg laminate is preheated for a predetermined time in the preheating device 3 heated to the melting temperature of the polypropylene resin or higher. As a preheating device, a press-type device capable of directly heating with a heating plate is preferable because it has good thermal conductivity, but an indirect heating type using far infrared rays as a heat source can also be used. In the case of a press type preheating device, in order to improve the releasability of the hot plate and the laminate, a polytetrafluoroethylene film, a sheet of glass cloth or a glass net impregnated with polytetrafluoroethylene, a release film such as a polyimide film. It is desirable to apply 4 to the hot plate surface. The press pressure when preheating the prepreg laminate is
It is usually performed at 3 kg / cm 2 or less within a range in which the linearity of the fibers of the laminate is not disturbed by the flow of the resin. The prepreg laminate 1 which has been preheated is taken out, and as shown in B, the laminate 1 is placed on the heat-insulated surface plate 5, and then the foam 2 is placed thereon. While pressing the laminated body 1 against the peripheral surface of the foamed body 2, the foamed body 2 is pressed by the pushing plate 6 as shown in B.
After being wound around the outside surface of the foamed body in sequence as indicated by C, along the inside of the cut portion, the molten laminate is pressed against the surface of the foamed body 2 by the holding plate 7. Since the holding plate 7 moves obliquely from above, the side surface and the bottom surface of the bumper beam structure can be uniformly pressed.

Next, as shown in D, the laminated body 1 which is turned over and is left unwound is superposed on the load receiving surface and pressed by the pressing plate 9 to bring the molten laminated body 1 into close contact with the foam 2.
Finally, cooling is performed, and the laminated body and the laminated body and the foamed body are adhered and solidified to obtain a bumper beam structure.
In this step, the pressure for melt-adhering the laminated body and the laminated body and the foamed body and the laminated body is preferably 3 kg / cm ² or less as in the preheating step. The impact resistance performance of the bumper beam structure thus obtained can be evaluated by a three-point bending test with both ends fixed as shown in FIG. The criteria for performance judgment are that the breaking load is high and the amount of bending at break is small.

FIG. 6 is a schematic view of a bending load test of the bumper beam structure. The flange portion of the load surface is fixed to the fixing jig 11 with the bolts 12, and the polypropylene resin foam 13 having a thickness of 30 mm and having a thickness of 30 mm is used as a cushioning material at the center of the bumper beam structure, and the diameter is
A load is applied through an iron loading jig 14 obtained by vertically dividing a 0 mm cylinder in half, and the deflection amount and load at break are measured.

[0027]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples. The sheet-like prepreg using the unidirectionally arranged fibers used in the examples of the present invention is disclosed in Japanese Patent Publication No. 04-4.
As described in No. 2168, 1800 yarns of 13μ monofilaments surface-treated with γ-methacryloxy-propyltrimethoxysilane are bundled in one direction while pulling the yarn in one direction while pulling it with uniform tension, and heat melting while pulling. It was manufactured by contacting the above-mentioned thermoplastic resin and impregnating the resin with a hot roll while squeezing. The grafted polypropylene resin added to the polypropylene resin used for the prepreg in order to improve the adhesion to the fiber is an organic peroxide in chlorobenzene which is a hydrocarbon solvent as described in JP-A-61-276846. Produced by graft-polymerizing a crystalline polypropylene resin (polypropylene homopolymer with MI = 30) using di-t-butyl peroxide which is a physical catalyst and maleic anhydride as a radically polymerizable unsaturated compound. did. This grafted polypropylene resin was added to a prepreg resin to produce a prepreg. Table 1 shows the flexural modulus of the matrix resin used in the prepreg used in the present invention, the amount of the grafted polypropylene resin added, the form of the glass fiber, and the fiber content in the prepreg. The bumper beam structures formed in the present example and the comparative example are the same as those in Example 3,
Except for Nos. 4 and 5, the weight was approximately 3 kg.

[Example 1] Using prepreg A, when the fiber direction of the prepreg was set to 0 degree, 90 from the top.
A laminated body 1 was prepared in which eight layers were stacked so that the upper and lower layers were orthogonal to each other at 0 degree, 0 degree, 90 degree, 0 degree, 0 degree, 90 degree, 0 degree, 90 degree. The laminate 1 was 1400 mm long and 580 mm wide, and was prepared so that the direction of the long side 1400 mm was 0 degrees. Furthermore, a polypropylene resin foam having a length of 1400 mm and a 15-fold expansion was prepared. The laminate 1 was preheated at 200 ° C. for 2 minutes at a pressure of 0.2 kg / cm ² by a preheating device shown by 3 in FIG.
A straight bumper beam structure shown in FIGS. 3 and 30A was molded with a molding pressure of ² kg / cm ² and a sectional shape of 20A in FIG. As shown in FIG. 6, the bumper beam structure was subjected to a bending load test by fixing the upper surface flange portion with bolts. The test conditions were that the upper surface of the cross-sectional shape shown in 20A of FIG.
Using a 20 type universal testing machine, in a bending test with both ends fixed, the distance between the fixing bolts is 1000 mm, and the loading speed is 20 mm /
Minutes The weight of the E2 / E1 and the structure for the bumper beam and the bending test result are shown in Table 2.

Example 2 A bumper beam structure was formed in the same manner as in Example 1. However, the entire shape of the bumper beam structure is an arch shape shown by 30B in FIG. The height of the arch is convex to the upper side by 50 mm with respect to the plane passing through both ends of the load surface. In the same manner as in Example 1, the weight of the bumper beam structure and the bending load test were performed. The results are shown in Table 2.

Example 3 A bumper beam structure was formed in the same manner as in Example 1. However, the overall shape of the bumper beam structure is an arch shape shown at 30C in FIG. The height of the arch is convex to the upper side by 50 mm with respect to the plane passing through both ends of the load surface. In the same manner as in Example 1, the weight of the bumper beam structure and the bending load test were performed. The results are shown in Table 2.

Example 4 A bumper beam structure was formed in the same manner as in Example 1. However, the shape of this bumper beam structure is 300 mm in the central portion as shown in FIG.
As shown in 0D, a laminated body having a thickness of 1.5 mm is wound only around the central portion of the bumper beam structure. In the same manner as in Example 1, the weight of the bumper beam structure and the bending load test were performed. The results are shown in Table 2.

Example 5 A bumper beam structure was formed in the same manner as in Example 1 except that a 30-fold expanded polystyrene resin foam was used instead of the 15-fold expanded polypropylene resin foam. The polystyrene resin foam inside the structure for a bumper beam was dissolved and removed by dropping acetone to obtain a structure for a bumper beam having a hollow cross-section without a foam. The weight measurement and the bending load test were performed in the same manner as in Example 1. The results are shown in Table 2.

Comparative Example 1 A bumper beam structure was formed in the same manner as in Example 1 except that prepreg B was used. In the same manner as in Example 1, the weight of the bumper beam structure and the bending load test were performed. The results are shown in Table 2.

Comparative Example 2 A molding pressure of 0.2 kg / cm
Except for using 5 kg / cm ² instead of ² was molded bumper beam structure in the same manner as in Example 1. However,
The foam collapsed and a normal bumper beam structure could not be molded.

Comparative Example 3 Prepreg A was used, and FIG.
A straight beam having a cross section of 1400 mm and having a length of 1400 mm was molded. In the same manner as in Example 1, the weight of the bumper beam structure and the bending load test were performed. The results are shown in Table 2.

COMPARATIVE EXAMPLE 4 Using prepreg A, FIG.
A straight beam having a cross-sectional shape shown in 10B and having a length of 1400 mm was molded. In the same manner as in Example 1, the weight of the bumper beam structure and the bending load test were performed. The results are shown in Table 2.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

EFFECTS OF THE INVENTION A structure made of a thermoplastic resin plate containing continuous fibers according to the present invention can be molded by low pressure, and a closed cross-sectional shape can be easily molded. By this method, it is possible to easily obtain a shape as designed by effectively utilizing the material property values of the fiber-reinforced thermoplastic resin, so that it is possible to supply a lightweight and high-strength bumper beam structure.

[Brief description of drawings]

FIG. 1 is a sectional view of a bumper beam structure manufactured by a conventional manufacturing method.

FIG. 2 is a cross-sectional view of a bumper beam structure according to the manufacturing method of the present invention.

FIG. 3 is an external perspective view of a bumper beam structure according to the manufacturing method of the present invention.

FIG. 4 is a detailed cross-sectional view of a bumper beam structure according to the manufacturing method of the present invention.

FIG. 5 is a schematic view of a method for manufacturing a bumper beam structure.

FIG. 6 is a schematic view of a bending load test of a bumper beam structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Laminated body 2 Foamed body 3 Press type preheating device 4 Release sheet 5 Heat-insulated surface plate 6 Push plate 7 Side bottom face plate 8 Presser plate moving direction 9 Top face plate 10A Bumper beam structure cross section 10B Bumper Beam structure cross-sectional shape 11 Bumper beam structure fixing portion 12 Bumper beam structure fixing bolt 13 Cushioning material 14 Loading jig 15 Bumper beam structure center thickened portion 16 Bumper beam structure Medium space 20A Cross-sectional shape of bumper beam structure 20B Cross-sectional shape of bumper beam structure 20C Cross-sectional shape of bumper beam structure 20D Cross-sectional shape of bumper beam structure 20E Cross-sectional shape of bumper beam structure 20F Bumper Cross-sectional shape of beam structure 20G Bumper Beam structure cross-section Jo 20H bumper beam structure cross section 30A straight bumper beam structure 30B arched bumper beam structure 30C arched bumper beam structure 30D central sensitization Atsujika shaped bumper beam structure

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[Procedure amendment]

[Submission date] June 24, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Change

[Correction content]

The present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view of a bumper beam structure manufactured by a conventional manufacturing method. FIG. 2 is a cross-sectional view of the bumper beam structure according to the manufacturing method of the present invention, but it is not necessarily limited to this shape.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08J 5/24 CES // B29K 23:00 105: 08 (72) Inventor Ryutaro Katsuta Sakae, Yokohama-shi, Kanagawa 1190 Kasama-machi, Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Hiroaki Tomimoto 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd. (72) Hiroshi Tanabe 1190, Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Address Mitsui Toatsu Chemical Co., Ltd. (72) Inventor Hideo Sakai 1190 Kasama-cho, Sakae-ku, Yokohama-shi, Kanagawa Mitsui Toatsu Chemical Co., Ltd.

Claims (8)

[Claims] 1. A continuous fiber in which a cross section taken along a plane perpendicular to a surface receiving a bending load forms a closed space, and a material forming the closed space is a unidirectional array of 40 to 80% by weight. The distance between the neutral axis of the cross-sectional shape that forms the closed space and the surface that receives the load is E
1. E is the distance between the neutral axis and the surface on the opposite side of the load-bearing surface
If the cross-sectional shape is the same in each part of the structure when it is set to 2, E
2 / E1 is 1.5 to 2.4, and when the cross-sectional shape is different in each part of the structure, the average value of the maximum value and the minimum value of E2 / E1 is 1.5 to 2.4. . 2. A thermoplastic resin foam foamed at a foaming ratio of 2 to 50 times is present in a closed space to integrate the thermoplastic resin containing continuous fibers with the foam. Item 1. The structure according to Item 1 or 2. 3. An elastic modulus of a thermoplastic resin containing fibers is 1
The structure according to claim 1 or ^2, which has a weight of 20 to 350 kg / mm ² . 4. The structure according to claim 1, wherein the thermoplastic resin is a polypropylene resin. 5. The structure according to claim 1, wherein the fibers are glass fibers. 6. A grafted thermoplastic resin containing 0.005 to 3.0 parts by weight of grafted polypropylene graft-polymerized with a radically polymerizable unsaturated compound is used as the thermoplastic resin. Structure. 7. The structure according to claim 1, wherein the surface that receives the bending load has a shape that bulges in an arcuate shape in the direction of receiving the load. 8. The structure according to claim 1, wherein a plate thickness of a surface which receives a bending load is partially thickened.