JP7223261B2 - automotive bumper beam - Google Patents

Description

The present invention relates to a bumper beam for motor vehicles.

Bumper beams made of fiber-reinforced resin are known, which are effective for reducing the weight of automobiles. Patent Document 1 discloses a bumper beam made of a fiber-reinforced thermoplastic resin stampable sheet in which discontinuous fibers are oriented in one direction. The discontinuous fibers are oriented in the longitudinal direction of the bumper.

In Patent Document 2, a unidirectional fiber reinforced resin sheet in which continuous reinforcing fibers are arranged in parallel in one direction is attached to the top and bottom of a hat-shaped thermoplastic resin molded product, and the hat-shaped side surface of the molded product is attached. discloses a bumper beam to which the sheet is not applied.

Patent Document 3 discloses a bumper beam having a Θ-shaped cross section, in which a cloth material in which reinforcing fibers are woven is used on the entire surface, and a unidirectional material in which continuous reinforcing fibers are aligned in one direction is attached to the bottom surface of the vehicle body. A bumper beam is disclosed for use in

JP-A-6-155495 JP 2013-184630 A WO2014/136858

The bumper beam of Patent Document 1 may break when a large load is applied because the reinforcing fibers are discontinuous fibers. That is, this bumper beam may not provide excellent energy absorption.

When the bumper beam of Patent Document 2 was subjected to a center pole collision test, the unreinforced standing surface (hat-shaped side surface) was opened and stretched in the longitudinal direction, and the bumper beam was broken. Energy absorption may not be obtained.

In Patent Literature 3, an attempt is made to improve the energy absorbability by positively compressing and destroying the cloth material of the standing surface. However, the cloth material is difficult to press-form, and it is very difficult to cover the entire surface of the complicated shape with the cloth material as in Patent Document 3. In addition, the cloth material has a lower mechanical strength than a unidirectionally oriented continuous fiber material (UD material), and the energy absorption using this low compressive strength is not high.

SUMMARY OF THE INVENTION An object of the present invention is to provide an automobile bumper beam made of fiber-reinforced resin, which can be easily press-molded and has excellent energy absorption properties.

The gist of the present invention resides in the following (1) to (10).

(1) An automobile bumper beam comprising a laminate of a carbon fiber reinforced portion comprising at least two carbon fiber reinforced resin layers (A) and a fiber reinforced portion comprising at least one fiber reinforced resin layer (B). and
Each of the carbon fiber reinforced resin layers (A) is made of a thermoplastic resin and continuous carbon fibers oriented in one direction,
At least one of the carbon fiber reinforced resin layers (A) is a carbon fiber reinforced resin layer (Aα) having an orientation angle of α, and at least one of the remaining carbon fiber reinforced resin layers (A). is a carbon fiber reinforced resin layer (Aβ) whose orientation angle is β, where the orientation angle is the angle formed by the orientation direction of the continuous carbon fibers with respect to the longitudinal direction of the bumper beam, and 45°≦α ≦75° and −45°≧β≧−75°,
The fiber-reinforced resin layer (B) is made of a thermoplastic resin and discontinuous reinforcing fibers,
At least one of two surfaces in the stacking direction of the laminate is formed of the carbon fiber reinforced portion,
Automotive bumper beam.

(2) The above (1), wherein the orientation angles of all the carbon fiber reinforced resin layers (A) are in the range of -90° or more and less than -15° or in the range of more than 15° and 90° or less. automotive bumper beam.

(3) The automobile bumper beam according to (2) above, wherein all the carbon fiber reinforced resin layers (A) have an orientation angle of α or β.

(4) In the carbon fiber reinforced portion, a carbon fiber reinforced resin layer (Aα) having an orientation angle of α and a carbon fiber reinforced resin layer (Aβ) having an orientation angle of β are arranged adjacent to each other. The automotive bumper beam according to (3) above, comprising at least one pair.

(5) The above (1), wherein one of the two surfaces in the stacking direction of the laminate is formed by the carbon fiber reinforced portion, and the other surface is formed by the other carbon fiber reinforced portion. The automobile bumper beam according to any one of (4) to (4).

(6) only one surface of the two surfaces in the stacking direction of the laminate is formed by the carbon fiber reinforced portion;
the carbon fiber reinforcement consists of a first portion of n said pairs and a second portion of another n said pairs, where n represents a positive integer;
The automotive bumper beam according to (4) above, wherein the lamination structure of the first portion and the lamination structure of the second portion are symmetrical in the lamination direction.

(7) one surface of the two surfaces in the stacking direction of the laminate is formed by the carbon fiber reinforced portion, and the other surface is formed by the other carbon fiber reinforced portion;
The carbon fiber reinforcement forming one surface of the two faces consists of m said pairs and the carbon fiber reinforcement forming the other surface consists of another m said pairs, where m represents a positive integer and
The automobile according to (4) above, wherein in the lamination direction, the lamination structure of the carbon fiber reinforced portion forming the one surface and the lamination structure of the carbon fiber reinforced portion forming the other surface are symmetrical. bumper beam.

(8) The automobile bumper beam according to any one of (1) to (7) above, wherein the absolute value of α is equal to the absolute value of β.

(9) The thermoplastic resin constituting the carbon fiber reinforced resin layer (A) and the thermoplastic resin constituting the fiber reinforced resin layer (B) may be polyamide, polycarbonate, and modified, respectively. The automobile bumper beam according to any one of (1) to (8) above, which is selected from polypropylene.

(10) The above (9), wherein the thermoplastic resin forming the carbon fiber reinforced resin layer (A) and the thermoplastic resin forming the fiber reinforced resin layer (B) are the same type of resin. 1. A bumper beam for a motor vehicle according to .

According to the present invention, it is possible to provide an automotive bumper beam made of fiber-reinforced resin, which is easy to press-mold and has excellent energy absorption properties.

(a) to (c) are cross-sectional schematic diagrams showing examples of bumper beams. It is a cross-sectional schematic diagram which shows the example of a carbon fiber reinforcement part. It is a schematic diagram for demonstrating an orientation angle. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows the model used for the simulation in the Example, The figure (a) is a front view of the whole model, The figure (b) is a side view of a test member. 4 is a graph showing displacement-load curves obtained in Examples. 4 is a graph showing displacement-load curves obtained in Examples.

The present inventors have found that laminating a continuous carbon fiber layer having high mechanical strength and orientation in one direction and a discontinuous fiber layer that is easy to mold is easy to press mold and has excellent energy absorption. We have found that this is effective for obtaining a bumper beam for automobiles made of fiber-reinforced resin. The present invention has been made based on such findings.

The automobile bumper beam according to the present invention is a laminate of a carbon fiber reinforced portion comprising at least two carbon fiber reinforced resin layers (A) and a fiber reinforced portion comprising at least one fiber reinforced resin layer (B). consists of That is, in the carbon fiber reinforced portion, at least two carbon fiber reinforced resin layers (A) are laminated. Moreover, when the fiber-reinforced portion is composed of two or more fiber-reinforced resin layers (B), the fiber-reinforced resin layers (B) are laminated.

・Carbon fiber reinforced resin layer (A)
Each carbon fiber reinforced resin layer (A) is composed of a thermoplastic resin and continuous carbon fibers oriented in one direction. That is, each carbon fiber reinforced resin layer (A) is formed of a unidirectional material in which continuous carbon fibers are oriented in one direction.

At least one of the carbon fiber reinforced resin layers (A) is a carbon fiber reinforced resin layer (Aα) having an orientation angle α, and at least one of the remaining carbon fiber reinforced resin layers (A) is oriented It is a carbon fiber reinforced resin layer (Aβ) having an angle β. Here, the orientation angle is the angle formed by the orientation direction of the continuous carbon fibers with respect to the longitudinal direction of the bumper beam in each carbon fiber reinforced resin layer (A). 45°≦α≦75° and −45°≧β≧−75°. Hereinafter, a carbon fiber reinforced resin layer (Aα) with an orientation angle of α is sometimes referred to as an "Aα layer", and a carbon fiber reinforced resin layer (Aβ) with an orientation angle of β is sometimes referred to as an "Aβ layer". When there are a plurality of Aα layers, all the Aα layers have the same orientation angle (α). When a plurality of Aβ layers are present, all the Aβ layers have the same orientation angle (β).

・Fiber reinforced resin layer (B)
The fiber-reinforced resin layer (B) consists of a thermoplastic resin and discontinuous reinforcing fibers. As the discontinuous reinforcing fibers, known reinforcing fibers in the field of fiber-reinforced resins, such as glass fibers, carbon fibers, and organic fibers, can be used. The average fiber length of the discontinuous reinforcing fibers is, for example, 5 mm or more and 100 mm or less.

The reinforcing fibers of the fiber-reinforced resin layer (B) do not have to be oriented. That is, in the fiber-reinforced resin layer (B), the reinforcing fibers may be arranged in random directions. Alternatively, the reinforcing fibers may have orientation. In that case, from the viewpoint of reducing anisotropy, it is preferable that the orientation angles of all the fiber-reinforced resin layers (B) are substantially 0° or 90°. The orientation angle of the fiber-reinforced resin layer (B) is the angle formed by the reinforcing fibers with respect to the longitudinal direction of the bumper beam.

Laminated structure In this specification, when the bumper beam is attached to the vehicle body, the direction facing the vehicle body is "rearward", the direction opposite to the rear is "forward", and the upward direction is "upper". The downward direction is called "downward," the rightward direction is called "rightward," and the leftward direction is called "leftward."

At least one surface of the two surfaces in the stacking direction of the laminate constituting the bumper beam is formed of the carbon fiber reinforced portion.

FIGS. 1(a) to 1(c) each schematically show a cross section of one example of a bumper beam (a cross section perpendicular to the longitudinal direction of the bumper beam). A laminate 1 forming a bumper beam has a hat-shaped cross section. In this laminate 1, a carbon fiber reinforced portion 10 and a fiber reinforced portion 20 are laminated. The stacking direction is the front-to-rear direction of the vehicle body at the portion forming the hat-shaped top surface (the most forward surface).

As shown in FIG. 1(a), the carbon fiber reinforced portion 10 may be arranged on the rear side and the fiber reinforced portion 20 may be arranged on the front side. Alternatively, as shown in FIG. 4B, the fiber reinforced portion 20 may be arranged on the rear side and the carbon fiber reinforced portion 10 may be arranged on the front side. In these cases, one carbon fiber reinforced portion 10 and one fiber reinforced portion 20 are present. Moreover, only one of the two surfaces in the stacking direction of the laminate 1 is formed by the carbon fiber reinforced portion 10 and the other surface is formed by the fiber reinforced portion 20 .

Alternatively, as shown in FIG. 1(c), the carbon fiber reinforced portions 10 may be arranged on both the rear side and the front side with the fiber reinforced portion 20 interposed therebetween. In this case, two carbon fiber reinforced portions 10 exist and one fiber reinforced portion 20 exists. Moreover, one of the two surfaces in the stacking direction of the laminate 1 is formed by the carbon fiber reinforced portion 10 and the other surface is formed by another carbon fiber reinforced portion 10 .

An example of the laminated structure of the carbon fiber reinforced portion 10 will be described with reference to FIG. In this carbon fiber reinforced portion 10, two carbon fiber reinforced resin layers (A) are laminated in the longitudinal direction of the vehicle body. For example, in the carbon fiber reinforced portion 10, the Aα layer 11 is arranged on the rear side and the Aβ layer 12 is arranged on the front side.

FIGS. 3A and 3B are schematic diagrams of the hat-shaped top surfaces of the Aα layer 11 and the Aβ layer 12, respectively, viewed from the rear side to the front side. The carbon fibers are oriented at an orientation angle α or β in a plane extending in the longitudinal direction of the bumper beam and in the vertical direction of the vehicle body.

The laminate 1 can include a carbon fiber reinforced resin layer whose orientation angle is neither α nor β. However, from the viewpoint of energy absorption of the bumper beam, the orientation angle of all the carbon fiber reinforced resin layers (A) contained in the laminate 1 is in the range of -90° or more and less than -15° or exceeds 15°, It is preferably in the range of 90° or less. The orientation is the same when the orientation angle is 90° and when the orientation angle is −90°. Further, it is more preferable that all the carbon fiber reinforced resin layers (A) have an orientation angle of α or β.

From the viewpoint of energy absorption of the bumper beam, it is preferable that the carbon fiber reinforced portion 10 consist of at least one pair in which one Aα layer 11 and one Aβ layer 12 are arranged adjacent to each other.

When only one surface of the two surfaces in the stacking direction of the laminate 1 is formed by the carbon fiber reinforced portion 10, the laminate 1 is made of carbon, particularly as shown in FIG. When only one fiber reinforced portion 10 is provided, the carbon fiber reinforced portion 10 is composed of a first portion consisting of n pairs (a pair of one Aα layer and one Aβ layer) and another and a second portion consisting of n said pairs (n represents a positive integer). In this case, it is more preferable that the lamination structure of the first portion and the lamination structure of the second portion are symmetrical in the lamination direction of the laminate 1 .

For example, in Example 4 described later, α = 45°, the first, third, sixth and eighth layers are Aα layers, β = -45°, the second, fourth, The fifth and seventh layers are Aβ layers. There is a first and second layer pair, a third and fourth layer pair, a sixth and fifth layer pair, and an eighth and seventh layer pair. In Example 4, n=4, the first to fourth layers form the first portion, and the fifth to eighth layers form the second portion. The lamination structure of the first portion and the lamination structure of the second portion are symmetrical in the lamination direction with respect to the interface between the fourth layer and the fifth layer. Note that the ninth to twelfth layers form the fiber reinforced portion 20 .

Further, when one of the two surfaces in the stacking direction of the laminate 1 is formed by the carbon fiber reinforced portion 10 and the other surface is formed by another carbon fiber reinforced portion 10, especially FIG. In the case where the carbon fiber reinforced portions 10 are provided on both sides of the fiber reinforced portion 20 as shown in c), the carbon fiber reinforced portions 10 forming one surface are composed of m pairs of carbon fiber reinforced portions 10 forming the other surface. Preferably, the fiber reinforced portion 10 consists of another m of said pairs (m represents a positive integer). In this case, in the stacking direction of the laminate 1, it is more preferable that the stacking structure of one carbon fiber reinforced portion 10 and the stacking structure of the other carbon fiber reinforced portion 10 are symmetrical.

For example, in Example 1 described later, α = 45 °, the first, third, tenth and 12th layers are Aα layers, and β = -45 °, the second, fourth, ninth and eleventh layers is the Aβ layer. In Example 1, the first to fourth layers form one carbon fiber reinforced portion 10 and the ninth to twelfth layers form the other carbon fiber reinforced portion 10 . There is a first and second layer pair, a third and fourth layer pair, a tenth and ninth layer pair, and a twelfth and eleventh layer pair. The layered structure of one carbon fiber reinforced portion 10 and the layered structure of the other carbon fiber reinforced portion 10 are symmetrical with the fiber reinforced portion 20 (fifth to eighth layers) interposed therebetween.

From the viewpoint of energy absorption of the bumper beam, it is preferable that the difference between the absolute value of α and the absolute value of β is, for example, 30° or less. Also, it is more preferable that the absolute value of α and the absolute value of β are equal.

The fiber-reinforced portion 20 is made of one or more fiber-reinforced resin layers (B).

・Thermoplastic resin The thermoplastic resin constituting the carbon fiber reinforced resin layer (A) and the thermoplastic resin constituting the fiber reinforced resin layer (B) are not particularly limited, but for example, nylon 6, nylon 66, nylon 12, Polyamides such as nylon MXD6; Polyolefins such as low-density polyethylene, high-density polyethylene, and polypropylene (which may be modified with acid or the like); Polyesters such as polyethylene terephthalate and polybutylene terephthalate; Polycarbonate; Polyamideimide; Polyether sulfone; polyether ether ketone; polyether imide; polystyrene; ABS resin; Modified polyolefin is, for example, acid-modified polyolefin obtained by modifying polyolefin with an acid such as maleic acid. The thermoplastic resin constituting the carbon fiber reinforced resin layer (A) and the thermoplastic resin constituting the fiber reinforced resin layer (B) may be used alone or in combination of two or more. good.

From the viewpoint of energy absorption and press moldability of the bumper beam, the thermoplastic resin constituting the carbon fiber reinforced resin layer (A) and the thermoplastic resin constituting the fiber reinforced resin layer (B) are polypropylene (acid, etc.). (which may be modified with ), polyamides, and polycarbonates.

Furthermore, from the viewpoint of adhesion, it is preferable that the thermoplastic resin forming the carbon fiber reinforced resin layer (A) and the thermoplastic resin forming the fiber reinforced resin layer (B) are the same type of resin. The fact that a plurality of resins are the same system means that the main components of the resins have common monomer units, or that the monomers of the main components of the resins are bonded to each other by the same functional group. For example, the thermoplastic resin constituting the carbon fiber reinforced resin layer (A) and the thermoplastic resin constituting the fiber reinforced resin layer (B) are each polypropylene (one or both of which may be modified with an acid or the like). Preferably. Moreover, each of these resins is preferably one selected from the group consisting of nylon 6 and nylon 66.

- Manufacturing method of bumper beam A carbon fiber reinforced resin sheet can be used to form the carbon fiber reinforced resin layer (A). A fiber-reinforced resin sheet can be used to form the fiber-reinforced resin layer (B). For example, the laminate 1 can be obtained by appropriately stacking a carbon fiber reinforced resin sheet and a fiber reinforced resin sheet and subjecting them to heat and pressure molding. The resulting laminate can be used as a bumper beam for automobiles. The carbon fiber reinforced portion can consist of a plurality of identical carbon fiber reinforced resin sheets. The fiber-reinforced portion can consist of a plurality of identical fiber-reinforced resin sheets. A unidirectional material is used as the carbon fiber reinforced resin sheet, the unidirectional material is arranged so that the orientation angle is α to form the Aα layer, and the unidirectional material is arranged so that the orientation angle is α to form the Aβ layer. β can be arranged.

The automobile bumper beam according to the present invention does not use a cloth material, so it can be easily manufactured by hot pressing.

- Shape of bumper beam The shape of the bumper beam is not particularly limited. For example, the cross section of the bumper beam may be a hat shape, a shape in which hat-shaped flanges are glued together, or a Θ shape.

[Example 1]
Simulation software (trade name: LS-DYNA, manufactured by LSTC) was used to evaluate the bumper beam composed of the laminate by simulation.

In the simulation, a model simulating a three-point bending test was created (see FIG. 4). The indenter 31 for the three-point bending test had an R (corner radius) of 75 mm, the two supports 32 had an R of 15 mm, and the distance between the fulcrums was 350 mm.

The test member was a hat channel (laminate 1) with a length of 400 mm. The hat shape was as follows (see FIG. 4(b)).
Width: 72mm,
height: 25mm,
thickness: 2mm,
Hat shape side taper: 93°,
Corner R: 4 mm,
Width of hat-shaped top surface (flat portion): 40 mm.

The indenter 31 and the support portion 32 were set as rigid bodies, and the hat channel (laminate 1) was set as a fiber-reinforced resin composite material. This fiber reinforced resin material is a laminate of a carbon fiber reinforced resin layer (A) and a fiber reinforced resin layer (B) using the material physical property database "Material 58 (* MAT_LAMINATED_COMPOSITE_FABRIC)" for anisotropic laminates. defined as

The fiber-reinforced resin layer (B) assumes a composite material (trade name: Unisheet P4038, made by Quadrant Plastic Composite Japan, manufactured by Quadrant Plastic Composite Japan, thermoplastic resin: polypropylene) using real discontinuous glass fibers, It was set as an isotropic material (denoted as "GMT" in the table) with a modulus of elasticity of 6,400 MPa and a modulus of elasticity perpendicular to the fiber of 6,400 MPa, and no failure was assumed.

The carbon fiber reinforced resin layer (A) assumes an existing unidirectional continuous fiber composite material (manufactured by Production Example 1 described later; thermoplastic resin: acid-modified polypropylene), and has an elastic modulus in the fiber direction of 101, 000 MPa and an elastic modulus in the direction perpendicular to the fiber of 4,600 MPa (indicated as "CFUD" in the table) as an anisotropic material. The compressive strength was set to 460 MPa and the tensile strength to 1570 MPa in the fiber direction, and the compressive strength was set to 70 MPa, the tensile strength to 21 MPa, and the shear strength to 207 MPa in the fiber orthogonal direction. In the simulation, the element was set to be removed when stress exceeding the above strength occurred in each element.

In the simulation, the contact between the indenter 31 and the hat channel (laminate 1) and the contact between the support 32 and the hat channel were defined as contact without restraint. Further, the indenter was set to move 40 mm in the stacking direction (direction from front to back) at a constant speed of 100 mm/s. As a result of the simulation, the amount of movement of the indenter and the reaction force received by the indenter are read, and by making a graph of the movement amount and reaction force at the same time, the relationship between displacement and load as confirmed in the three-point bending test can be obtained. It was reproduced (see FIGS. 5 and 6).

As an index representing the energy absorbability of the bumper beam, the displacement indicating the maximum load value in the displacement-load curve thus obtained was evaluated. It can be said that the larger the displacement indicating the maximum load value, the better the energy absorption.

The lamination structure of the hat channel was as shown in the table below from the support portion 32 side toward the indenter 31 side. The first layer is closest to the support portion 32 (most rearward side), and the twelfth layer is closest to the indenter 31 (most forward side). All carbon fiber reinforced resin layers (A) are made of the same material (they are the same except for the orientation angle). All the fiber-reinforced resin layers (B) are made of the same material (they are the same except for the orientation angle). Although four fiber-reinforced resin layers (B) each having a thickness of 0.25 mm are superimposed, this is merely for convenience of simulation. These four fiber-reinforced resin layers (B) may actually be one layer with a thickness of 1 mm. The same applies to other examples.

The maximum load was 3710N and the displacement at that time was 24mm.

・Manufacturing example 1
The unidirectional continuous fiber composite material assumed here as the carbon fiber reinforced resin layer (A) was produced as follows. Carbon fibers (trade name: Pyrofil TR 50S, manufactured by Mitsubishi Chemical Co., Ltd., carbon fiber diameter 7 μm) were aligned in one direction and flat to form a fiber sheet having a basis weight of 72 g/m ² . The fiber sheet was sandwiched from both sides by films having a basis weight of 36 g/m ² made of acid-modified polypropylene resin (trade name: Modic P958V, manufactured by Mitsubishi Chemical). These were passed through calender rolls multiple times to be heated and pressurized to impregnate the fiber sheet with the resin to produce a unidirectional continuous fiber composite material having a fiber volume content (Vf) of 33% by volume and a thickness of 125 μm.

[Example 2]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 3730N and the displacement at that time was 32mm.

[Example 3]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 3770N and the displacement was 40mm.

[Comparative Example 1]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 2290N and the displacement at that time was 9mm.

[Comparative Example 2]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 3340N and the displacement at that time was 16mm.

[Example 4]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 2650N and the displacement at that time was 23mm.

[Example 5]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 2660N and the displacement at that time was 27mm.

[Example 6]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 2730 N and the displacement at that time was 31 mm.

[Comparative Example 3]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 2270N and the displacement at that time was 9mm.

[Comparative Example 4]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 2520N and the displacement at that time was 15mm.

[Example 7]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 2470N and the displacement at that time was 25mm.

[Comparative Example 5]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 2740N and the displacement at that time was 11 mm.

[Example 8]
The lamination structure was as shown in the table below. Here, the fiber-reinforced resin layer (B) is assumed to be a composite material using actual discontinuous carbon fibers (manufactured by Production Example 2 described later. Thermoplastic resin: acid-modified polypropylene). It was set as an anisotropic material (denoted as "CMT" in the table) with a modulus of elasticity of 29,600 MPa and a modulus of elasticity perpendicular to the fiber of 18,000 MPa. The compressive strength was set at 340 MPa and the tensile strength at 340 MPa in the fiber direction, and the compressive strength was set at 250 MPa, the tensile strength at 250 MPa and the shear strength at 207 MPa in the direction perpendicular to the fiber.

Evaluation was performed in the same manner as in Example 1 except for the above. The maximum load was 4810N and the displacement at that time was 21 mm.

・Manufacturing example 2
A rectangular sheet of 220 mm (0° direction with respect to the fiber axis)×900 mm (90° direction with respect to the fiber axis) was cut out from the unidirectional continuous fiber composite material obtained in Production Example 1. Using a cutting plotter (trade name: L-2500 cutting plotter, manufactured by Leathac), the absolute value of the angle formed with the fiber axis of the reinforcing fiber is 45 °, and the fiber length of the reinforcing fiber is 25 mm. Incisions were made to a depth sufficient to cut the reinforcing fibers to obtain a sheet with incisions. A sheet laminate was obtained by laminating two of the cut sheets such that the fiber axes of the reinforcing fibers are in the same direction. The thickness of the sheet laminate was 0.25 mm. As a pressurizing device, it is equipped with two-stage press rolls whose axial direction coincides with the direction perpendicular to the running direction of the material (the sheet laminate), and a double belt type in which the upper and lower belts are driven at 1.0 m / min. A heating press was used. The sheet laminate was put into the double belt type heating and pressing machine so that the angle formed by the direction of the fiber axes of the reinforcing fibers with respect to the orthogonal direction was 0°. In the double-belt type heating and pressurizing machine, the sheet laminate was heated and pressurized in a state where the thermoplastic resin was melted by a two-stage press roll with a roll temperature of 270° C. and a linear pressure of 10.7 N/m. . After that, it is passed through a 1.5 m cooling section equipped with a single-stage hot water roll under the conditions of a roll temperature of 30 ° C. and a linear pressure of 2.5 N / m to solidify the thermoplastic resin and use discontinuous carbon fibers. A composite material was obtained. The running speed of the sheet laminate was the same as the driving speed of the belt.

[Example 9]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 4490N and the displacement at that time was 26mm.

[Example 10]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 3780 and the displacement at that time was 28 mm.

[Comparative Example 6]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 3520 and the displacement at that time was 10 mm.

[Comparative Example 7]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 4310 and the displacement at that time was 14 mm.

[Example 11]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 4440N and the displacement at that time was 23mm.

[Example 12]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 4300N and the displacement at that time was 27mm.

[Example 13]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 3720N and the displacement at that time was 27mm.

[Comparative Example 8]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 3470N and the displacement at that time was 10mm.

[Comparative Example 9]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 3580N and the displacement at that time was 10mm.

[Comparative Example 10]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 3960N and the displacement at that time was 16mm.

[Example 14]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 4950N and the displacement at that time was 22mm.

[Example 15]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 4110N and the displacement at that time was 24mm.

[Example 16]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 3430N and the displacement at that time was 24mm.

[Comparative Example 11]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 4570N and the displacement at that time was 12mm.

[Comparative Example 12]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 5120N and the displacement at that time was 18mm.

[Comparative Example 13]
Evaluation was performed in the same manner as in Example 8, except that the laminated structure was as shown in the table below. The maximum load was 3050N and the displacement at that time was 20mm.

[Example 17]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 3730N and the displacement at that time was 27mm.

[Example 18]
Evaluation was performed in the same manner as in Example 1, except that the laminated structure was as shown in the table below. The maximum load was 3820N and the displacement at that time was 30mm.

The above results are summarized in Tables 32 and 33. In these tables, conventional notation is used to abbreviate the stacking configurations, but the stacking configuration for each example is detailed above. In addition, "s" in the said abbreviation means "symmetrical."

FIG. 5 shows the displacement-load curves obtained in Examples 8-10 and Comparative Examples 6-7. FIG. 6 shows the displacement-load curves obtained in Examples 14-16 and Comparative Examples 11-13. The aforementioned maximum load and the displacement that gives the maximum load are read from such a curve.

1 Laminate constituting a bumper beam 10 Carbon fiber reinforced portion 11 Carbon fiber reinforced resin layer 12 having an orientation angle α Carbon fiber reinforced resin layer 20 having an orientation angle β Fiber reinforced portion

Claims (6)

An automotive bumper beam comprising a laminate of a carbon fiber reinforced portion comprising at least two carbon fiber reinforced resin layers (A) and a fiber reinforced portion comprising at least one fiber reinforced resin layer (B). ,
Each of the carbon fiber reinforced resin layers (A) is made of a thermoplastic resin and continuous carbon fibers oriented in one direction,
At least one of the carbon fiber reinforced resin layers (A) is a carbon fiber reinforced resin layer (Aα) having an orientation angle of α, and at least one of the remaining carbon fiber reinforced resin layers (A). is a carbon fiber reinforced resin layer (Aβ) whose orientation angle is β, where the orientation angle is the angle formed by the orientation direction of the continuous carbon fibers with respect to the longitudinal direction of the bumper beam, and 45°≦α ≦75° and −45°≧β≧−75°,
The fiber-reinforced resin layer (B) is made of a thermoplastic resin and discontinuous reinforcing fibers,
At least one surface of the two surfaces in the stacking direction of the laminate is formed by the carbon fiber reinforced portion,
The orientation angles of all the carbon fiber reinforced resin layers (A) are in the range of -90° or more and less than -15° or in the range of more than 15° and 90° or less,
The orientation angle of all the carbon fiber reinforced resin layers (A) is α or β,
At least one carbon fiber reinforced resin layer (Aα) having an orientation angle of α and a carbon fiber reinforced resin layer (Aβ) having an orientation angle of β are arranged adjacent to each other. consists of a pair,
Only one surface of the two surfaces in the stacking direction of the laminate is formed by the carbon fiber reinforced portion,
the carbon fiber reinforcement consists of a first portion of n said pairs and a second portion of another n said pairs, where n represents a positive integer;
A bumper beam for a motor vehicle, wherein, in the stacking direction, the stacking configuration of the first portion and the stacking configuration of the second portion are symmetrical. 2. The automobile according to claim 1, wherein one surface of the two surfaces in the stacking direction of the laminate is formed by the carbon fiber reinforced portion, and the other surface is formed by the other carbon fiber reinforced portion. for bumper beam. An automotive bumper beam comprising a laminate of a carbon fiber reinforced portion comprising at least two carbon fiber reinforced resin layers (A) and a fiber reinforced portion comprising at least one fiber reinforced resin layer (B). ,
Each of the carbon fiber reinforced resin layers (A) is made of a thermoplastic resin and continuous carbon fibers oriented in one direction,
At least one of the carbon fiber reinforced resin layers (A) is a carbon fiber reinforced resin layer (Aα) having an orientation angle of α, and at least one of the remaining carbon fiber reinforced resin layers (A). is a carbon fiber reinforced resin layer (Aβ) whose orientation angle is β, where the orientation angle is the angle formed by the orientation direction of the continuous carbon fibers with respect to the longitudinal direction of the bumper beam, and 45°≦α ≦75° and −45°≧β≧−75°,
The fiber-reinforced resin layer (B) is made of a thermoplastic resin and discontinuous reinforcing fibers,
At least one surface of the two surfaces in the stacking direction of the laminate is formed by the carbon fiber reinforced portion,
The orientation angles of all the carbon fiber reinforced resin layers (A) are in the range of -90° or more and less than -15° or in the range of more than 15° and 90° or less,
The orientation angle of all the carbon fiber reinforced resin layers (A) is α or β,
At least one carbon fiber reinforced resin layer (Aα) having an orientation angle of α and a carbon fiber reinforced resin layer (Aβ) having an orientation angle of β are arranged adjacent to each other. consists of a pair,
one surface of the two surfaces in the stacking direction of the laminate is formed by the carbon fiber reinforced portion, and the other surface is formed by the other carbon fiber reinforced portion;
wherein the carbon fiber reinforcement forming one of said two surfaces consists of m said pairs and the carbon fiber reinforcement forming the other surface consists of another m said pairs, m represents a positive integer,
A bumper beam for an automobile , wherein a lamination structure of the carbon fiber reinforced portion forming the one surface and a lamination structure of the carbon fiber reinforced portion forming the other surface are symmetrical in the lamination direction. 4. The automotive bumper beam according to any one of claims 1 to 3 , wherein the absolute value of [alpha] and the absolute value of [beta] are equal. The thermoplastic resin constituting the carbon fiber reinforced resin layer (A) and the thermoplastic resin constituting the fiber reinforced resin layer (B) are each selected from polyamide, polycarbonate, and optionally modified polypropylene. A bumper beam for motor vehicles according to any one of claims 1 to 4 . 6. The automobile according to claim 5 , wherein the thermoplastic resin forming the carbon fiber reinforced resin layer (A) and the thermoplastic resin forming the fiber reinforced resin layer (B) are the same type of resin. for bumper beam.

Images