JP2019182166A - Vehicle structure member - Google Patents

Abstract

In a structural member for a vehicle, energy absorption performance at the time of a vehicle collision is improved while reducing the weight.
A ceiling wall portion 2a extending in the longitudinal direction, a pair of side wall portions 2b rising from both ends of the ceiling wall portion 2a, and a bottom wall portion 3a facing the ceiling wall portion 2a, and the ceiling wall portion 2a, a pair of side wall portions 2b and a bottom wall portion 3a form a closed cross section, and a hollow member 10 provided with a bending induction portion 7 in a part in the longitudinal direction, and a metal hollow member 10 adjacent to the bending induction portion 7. The vehicular structural member 1 is configured so as to include a reinforcing member 4 made of FRP joined to the adjacent portion 8 that is a portion to be operated.
[Selection] Figure 1

Description

  The present invention relates to a vehicle structural member.

  In recent years, from the viewpoint of protecting the global environment, there has been a demand for improving the fuel efficiency of automobiles. On the other hand, maintenance or improvement of vehicle crash safety is required. In order to satisfy these requirements, development of a high-strength and lightweight vehicle body structure is underway. With regard to frames that are structural members for vehicles and form the framework of the vehicle body, in order to reduce the weight of the vehicle body structure while maintaining the conventional collision performance, the strength and thickness of the steel plate forming the frame are being increased. ing.

  Further, in order to improve the collision safety of the vehicle, it is required to improve the energy absorption performance of the front and rear portions of the vehicle, which is also called “crushable zone”. For example, the crushable zone of the front part is mainly composed of a part called a front side member and a part called a crush box arranged at the tip thereof. Here, as a technique for improving the energy absorption performance of the front portion of the vehicle, Patent Document 1 discloses a technique in which FRP (fiber reinforced resin) is applied to a crash box (bumper beam extension) at the front of the vehicle body. As a technique for improving the energy absorption performance of the rear part of the vehicle, Patent Document 2 discloses a technique in which FRP is applied to a crash box (crash rail) at the rear of the vehicle body.

International Publication No. 2014/042211 International Publication No. 2014/112265

  The techniques disclosed in Patent Document 1 and Patent Document 2 apply FRP to a crash box and improve the energy absorption performance of the crash box itself. However, the crash box is a member intended to absorb energy in a collision with a small input load (so-called light collision), for example, at a low speed collision, and has a large input load, for example, at a high speed collision. In the case of, the crash box is crushed in the initial stage of deformation, and then the front side member is deformed to absorb energy. Since the amount of energy absorbed by the crash box is relatively small compared to the front side member, the crash box can only exhibit limited energy absorption performance when a large load is assumed during a high-speed collision. On the other hand, there are almost no examples of application of FRP (fiber reinforced resin) to a front side member that mainly absorbs energy during high-speed collision. This is because the ductility of the FRP is extremely small, so that the FRP is broken at the initial stage of deformation for a large load at the time of high-speed collision, and a target energy absorption amount cannot be obtained.

  The present invention has been made in view of the above problems, and an object of the present invention is to improve the energy absorption performance at the time of a vehicle collision while reducing the weight of the structural member for a vehicle.

  One aspect of the present invention that solves the above-described problems is a structural member for a vehicle, and includes a top wall portion extending in a longitudinal direction, a pair of side wall portions standing from both ends of the top wall portion, and facing the top wall portion. And a metal hollow member having a closed cross section formed by the top wall portion, the pair of side wall portions, and the bottom wall portion, and having a bending inducing portion in a part of the longitudinal direction. And a reinforcing member made of FRP, which is joined to an adjacent portion that is a portion adjacent to the bending induction portion of the hollow member.

  In the vehicle structural member, the FRP member is joined to the adjacent portion adjacent to the bending induction portion of the metal hollow member, so that the out-of-plane deformation of the adjacent portion can be suppressed. For this reason, the out-of-plane deformation of the adjacent portion when the bending induction portion buckles is suppressed, and the deformation of the hollow member proceeds while generating a higher reaction force than before. In addition, although the ductility of FRP is extremely low, the adjacent portion adjacent to the bending induction portion does not instantly undergo large deformation, and since the deformation progresses gradually, the FRP also gradually breaks through the later stages of deformation. It is possible to absorb energy while doing so. Thereby, the energy absorption performance as a structural member improves.

  ADVANTAGE OF THE INVENTION According to this invention, in the structural member for vehicles, the energy absorption performance at the time of a vehicle collision can be improved, aiming at weight reduction.

1 is a perspective view showing a schematic configuration of a vehicle frame according to an embodiment of the present invention. It is a figure which shows the aa cross section in FIG. It is a perspective view which shows schematic structure of the vehicle frame which concerns on the same embodiment. In addition, illustration of the 1st structural member of a hollow member is abbreviate | omitted in this figure. It is sectional drawing which shows the cross section orthogonal to the Z-axis direction of the flame | frame concerning the embodiment. It is a figure which shows the deformation | transformation state of the flame | frame at the time of the collision concerning the embodiment. FIG. 5 is an enlarged view of the vicinity of a bent portion in FIG. 4. It is a perspective view of a frame for explaining the 1st example of arrangement of a reinforcing member concerning the embodiment. In the drawing, the illustration of the first structural member of the hollow member is partially omitted. It is a figure which shows the bb cross section in FIG. It is a perspective view of a frame for explaining the 2nd example of arrangement of a reinforcing member concerning the embodiment. In the drawing, the illustration of the first structural member of the hollow member is partially omitted. It is a figure which shows the cc cross section in FIG. It is a figure which shows the dd cross section in FIG. It is a perspective view of a frame for explaining the 3rd example of arrangement of a reinforcing member concerning the embodiment. In the drawing, the illustration of the first structural member of the hollow member is partially omitted. It is a figure which shows the ee cross section in FIG. It is a figure which shows the ff cross section in FIG. It is sectional drawing of the flame | frame for demonstrating the example of the hole provided in the hollow member which concerns on the same embodiment. It is a perspective view of a frame for explaining an example of a hole provided in a hollow member concerning the embodiment. It is a schematic diagram which shows the other example of the hole provided in the hollow member which concerns on the embodiment. It is a schematic diagram which shows the other example of the hole provided in the hollow member which concerns on the embodiment. It is a schematic diagram which shows the other example of the hole provided in the hollow member which concerns on the embodiment. It is sectional drawing of the flame | frame for demonstrating the example of the bead part provided in the hollow member which concerns on the embodiment. It is a perspective view of the flame | frame for demonstrating the example of the bead part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the recessed part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the recessed part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the recessed part provided in the hollow member which concerns on the same embodiment. It is a mimetic diagram showing an example of the shape and size of a crevice concerning the embodiment. It is a schematic diagram which shows the other example of the recessed part provided in the hollow member which concerns on the same embodiment. It is sectional drawing of the flame | frame for demonstrating the example of the convex part provided in the hollow member which concerns on the same embodiment. It is a perspective view of a frame for explaining an example of a convex part provided in a hollow member concerning the embodiment. It is a schematic diagram which shows the other example of the convex part provided in the hollow member which concerns on the embodiment. It is a schematic diagram which shows the other example of the convex part provided in the hollow member which concerns on the embodiment. It is a schematic diagram which shows the other example of the convex part provided in the hollow member which concerns on the embodiment. It is a schematic diagram which shows an example of the shape and magnitude | size of a convex part which concern on the embodiment. It is a schematic diagram which shows the other example of the convex part provided in the hollow member which concerns on the embodiment. It is a schematic diagram which shows an example of the board thickness change part provided in the hollow member which concerns on the embodiment. It is a schematic diagram which shows an example of the thin part provided in the hollow member which concerns on the embodiment. It is sectional drawing of the flame | frame for demonstrating the example of the different intensity | strength part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the different intensity | strength part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the different intensity | strength part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows an example of the intensity | strength change part provided in the hollow member which concerns on the embodiment. It is sectional drawing of the flame | frame for demonstrating the example of the combination of the bending part provided in the hollow member which concerns on embodiment, and a hole part. It is sectional drawing which shows the cross section orthogonal to the longitudinal direction of the 1st example of the hollow member which concerns on other embodiment of this invention. It is sectional drawing which shows the cross section orthogonal to the longitudinal direction of the 2nd example of the hollow member which concerns on other embodiment of this invention. It is a perspective view of the flame | frame for demonstrating arrangement | positioning of the reinforcement member in a comparative example. In the drawing, the illustration of the first structural member of the hollow member is partially omitted. It is a figure which shows the gg cross section in FIG. It is a perspective view of the flame | frame for demonstrating arrangement | positioning of the reinforcement member in a comparative example. In the drawing, the illustration of the first structural member of the hollow member is partially omitted. It is a figure which shows the hh cross section in FIG. It is a perspective view of the flame | frame for demonstrating arrangement | positioning of the reinforcement member in a comparative example. In the drawing, the illustration of the first structural member of the hollow member is partially omitted. It is a figure which shows the ii cross section in FIG. It is a figure which shows the energy absorption performance of each analysis model in a collision simulation. It is a figure which shows the energy absorption performance of each analysis model in a collision simulation. It is a figure which shows the energy absorption performance of each analysis model in a collision simulation. It is a figure which shows the magnitude | size of the initial reaction force of each analysis model in a collision simulation.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the present specification and drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, and redundant description is omitted.

<1. Target of application of structural members for vehicles>
Before describing the configuration of a vehicle frame that is an example of a vehicle structural member, an application target of the vehicle structural member will be described. A vehicle body provided in a vehicle such as a general automobile can be classified into a front structure (FRONT), a rear structure (REAR), and a cabin structure (CABIN).

  The front structure and the rear structure have a function (impact absorption function) of absorbing and mitigating an impact on the vehicle by the structure itself being crushed when the vehicle collides. That is, in order to ensure the safety of passengers riding in the cabin in the event of a vehicle collision, the front structure and the rear structure are required to have a structure that absorbs energy (collision energy) generated by the collision as much as possible. Therefore, the frames constituting the front structure and the rear structure are required to absorb a lot of collision energy even when the frame is bent or crushed at the time of collision. The frame used for the front structure and the rear structure is, for example, a front side member, a rear side member, or the like. The front side member includes a front side member rear that constitutes a rear end portion, and a front side member front that constitutes a front portion of the rear end portion. The rear side member includes a rear side member rear that constitutes a rear end portion, and a rear side member front that constitutes a front portion of the rear end portion.

  By the way, in order to achieve both the maintenance of the collision safety of the vehicle and the reduction in weight, the steel sheet forming the vehicle body structure has been increased in strength and thickness. The frame constituting the front structure, the rear structure, and the cabin structure is also being replaced with a thinned high-strength steel plate. Specifically, the thickness of the frame formed of the high-strength steel plate is less than that of the conventional steel plate so that at least one of the collision energy absorption amount and the load bearing performance is equivalent to the frame formed of the conventional steel plate. It is set thinner than the frame to be formed. Thereby, the weight of the frame can be reduced while maintaining the collision performance of the high-strength frame equal to that of the conventional frame.

<2. Configuration of vehicle frame>
(Frame components)
FIG. 1 is a perspective view showing a schematic configuration of a vehicle frame 1 according to an embodiment of the present invention. The vehicle frame 1 in this specification is an example of a vehicle structural member, and is simply referred to as the frame 1 hereinafter. The frame 1 is preferably applied to a member related to a front structure and a rear structure, but the vehicle frame 1 can also be applied to a member related to a cabin structure. Moreover, the said structural member for vehicles is applicable not only to a motor vehicle but another vehicle and the machine which can be self-propelled. Other vehicles and self-propelled machines include, for example, two-wheeled vehicles, large vehicles such as buses or towing vehicles, trailers, railway vehicles, construction machinery, mining machinery, agricultural machinery, general machinery, and ships.

  As shown in FIGS. 1 and 2, the frame 1 of the present embodiment includes a first structural member 2, a second structural member 3, and a reinforcing member 4 (4A to 4C) made of CFRP.

  The first structural member 2 of the present embodiment is an example of a long structural member and has a hat-shaped cross-sectional shape. The first structural member 2 has a top wall 2a, side walls 2b and 2b, flanges 2c and 2c, and ridges 2d, 2d, 2e and 2e extending in the longitudinal direction (X-axis direction).

  The side wall 2b is provided upright from both ends in the Z-axis direction (vertical direction) of the top wall 2a. The side wall 2b is often provided at a substantially vertical angle with respect to the top wall 2a from the viewpoint of collision performance, but the angle formed between the side wall 2b and the top wall 2a is substantially vertical. It is appropriately set according to the design of the first member. The ridge line portion 2d is a portion that becomes a boundary between the top wall portion 2a and the side wall portion 2b, and is a connection portion between the top wall portion 2a and the side wall portion 2b.

  The flange portion 2c is provided to stand on the outer side along the Z-axis direction from the end opposite to the top wall portion 2a of the side wall portion 2b. The flange portion 2c is often provided at a substantially vertical angle with respect to the side wall portion 2b, but the angle formed between the flange portion 2c and the side wall portion 2b is not limited to a substantially vertical angle, depending on the design of the member. To be determined as appropriate. Moreover, the ridgeline part 2e is a part used as the boundary of the side wall part 2b and the flange part 2c.

  The 2nd structural member 3 of this embodiment is an example of a long structural member, and is a plate-shaped member. The second structural member 3 has a bottom wall portion 3a and joint portions 3c and 3c.

  The bottom wall portion 3 a is a portion facing the top wall portion 2 a of the first structural member 2. Further, the joint portion 3c is a portion that contacts the flange portion 2c of the first structural member 2 and is joined to the flange portion 2c. That is, the bottom wall portion 3a is a portion corresponding to a region existing between the connection portions of the second structural member 3 and the pair of ridge line portions 2e. Further, the joint portion 3c is a portion that contacts the region of the flange portion 2c sandwiched between the ridge line portion 2e and the end portion of the flange portion 2c in the second structural member 3.

  In this embodiment, the 1st structural member 2 and the 2nd structural member 3 are joined by joining the flange part 2c and the junction part 3c. Thereby, the hollow member 10 whose cross section perpendicular | vertical to a longitudinal direction becomes a closed cross section is comprised by the top wall part 2a, a pair of side wall parts 2b and 2b, and the bottom wall part 3a. In the following description, the term “longitudinal direction” simply refers to the longitudinal direction of the hollow member 10. In addition, the joining method of the flange part 2c and the junction part 3c is not specifically limited. For example, the joining method may be welding, rivet or bolt fastening. In this embodiment, the flange part 2c and the junction part 3c are joined by spot welding.

  The shape of the closed cross section of the hollow member 10 is substantially polygonal. Here, the substantially polygonal shape means a closed plane figure that can be approximated by a plurality of line segments. For example, the closed cross section of the hollow member 10 of the present embodiment has four line segments (corresponding to the top wall portion 2a, the pair of side wall portions 2b, and the bottom wall portion 3a) and four vertices (corresponding to the ridge line portions 2d and 2e). It is a substantially quadrangle consisting of This substantially quadrilateral includes a rectangle, a trapezoid, and the like. Even if the shape of the closed section of the hollow member 10 is a substantially polygonal shape other than a substantially rectangular shape, in this specification, the hollow member 10 includes the top wall portion 2a, the pair of side wall portions 2b, 2b, and the bottom. It demonstrates as what is formed by the wall part 3a. The hollow member 10 may have an integral cross section without the flange portion 2c, that is, a prismatic cross section. An example of the closed cross-sectional shape of the hollow member 10 will be described later.

  It is preferable that the 1st structural member 2 and the 2nd structural member 3 are formed with metal plates, such as a steel plate, for example. From the viewpoint of collision performance, the plate thickness of both structural members is preferably 6.0 mm or less in a frame structure that is often used in large vehicles such as buses, and in a monocoque structure vehicle that is often used in a normal size vehicle. It is preferable that it is 2 mm or less. Moreover, the intensity | strength of the 1st structural member 2 and the 2nd structural member 3 is not specifically limited. However, in order to compensate for the overall strength of the frame, which can be reduced by weight reduction, it is preferable that the tensile strength of both structural members 2 and 3 is 590 MPa or more. Moreover, it is more preferable that the tensile strength of both structural members 2 and 3 is 980 MPa or more.

  The reinforcing member 4 (4A to 4C) made of CFRP is an example of a reinforcing member (FRP member) made of FRP (fiber reinforced resin).

<3. Examples of reinforcing members>
FRP that can be used for a reinforcing member (also referred to as FRP member) means a fiber reinforced resin that is composed of a matrix resin and a reinforced fiber material that is contained in the matrix resin and combined.

  As the reinforcing fiber material, for example, carbon fiber or glass fiber can be used. In addition, boron fiber, silicon carbide fiber, aramid fiber, or the like can be used as the reinforcing fiber material. In the FRP used for the FRP member, examples of the reinforcing fiber base material used as the base material of the reinforcing fiber material include, for example, a nonwoven fabric base material using chopped fibers, a cloth material using continuous fibers, and a unidirectional reinforcing fiber base material (UD). Material) etc. can be used. These reinforcing fiber bases can be appropriately selected according to the orientation of the reinforcing fiber material.

  CFRP is FRP using carbon fiber as a reinforcing fiber material. As the carbon fiber, for example, a PAN-based or pitch-based one can be used. By using the carbon fiber, the strength with respect to weight can be improved efficiently.

  GFRP is FRP using glass fiber as a reinforcing fiber material. Although it is inferior to a carbon fiber in mechanical characteristics, it can suppress the electric corrosion of a metal member.

  As a matrix resin used for FRP, either a thermosetting resin or a thermoplastic resin can be used. Examples of the thermosetting resin include epoxy resins, unsaturated polyester resins, and vinyl ester resins. As thermoplastic resins, polyolefins (polyethylene, polypropylene, etc.) and acid-modified products thereof, polyamide resins such as nylon 6 and nylon 66, thermoplastic aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, polyethersulfone And polyphenylene ether and modified products thereof, polyarylate, polyetherketone, polyetheretherketone, polyetherketoneketone, styrene resins such as vinyl chloride and polystyrene, and phenoxy resin. The matrix resin may be formed of a plurality of types of resin materials.

  Considering application to a metal member, it is preferable to use a thermoplastic resin as a matrix resin from the viewpoint of workability and productivity. Furthermore, the density of the reinforcing fiber material can be increased by using a phenoxy resin as the matrix resin. Moreover, since the phenoxy resin has a molecular structure very similar to that of an epoxy resin that is a thermosetting resin, the phenoxy resin has a heat resistance comparable to that of an epoxy resin. Moreover, application to a high temperature environment is also possible by further adding a curing component. When a curing component is added, the amount added may be determined appropriately in consideration of the impregnation into the reinforcing fiber material, the brittleness of the FRP, the tact time, the workability, and the like.

<Adhesive resin layer>
When the reinforcing member is formed of an FRP member or the like, an adhesive resin layer is provided between the FRP member and the metal member (hollow member 10 in the above embodiment), and the FRP member and the metal member are joined by the adhesive resin layer. May be.

  The kind of adhesive resin composition which forms an adhesive resin layer is not specifically limited. For example, the adhesive resin composition may be either a thermosetting resin or a thermoplastic resin. The kind of thermosetting resin and thermoplastic resin is not particularly limited. Examples of thermoplastic resins include polyolefins and acid-modified products thereof, polystyrene, polymethyl methacrylate, AS resin, ABS resin, thermoplastic aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, polyimide, polyamide, polyamide Use one or more selected from imide, polyetherimide, polyethersulfone, polyphenylene ether and modified products thereof, polyphenylene sulfide, polyoxymethylene, polyarylate, polyetherketone, polyetheretherketone, and polyetherketoneketone can do. Moreover, as a thermosetting resin, 1 or more types chosen from an epoxy resin, a vinyl ester resin, a phenol resin, and a urethane resin can be used, for example.

  The adhesive resin composition can be appropriately selected according to the characteristics of the matrix resin constituting the FRP member, the characteristics of the reinforcing member, or the characteristics of the metal member. For example, the adhesiveness is improved by using a resin having a polar functional group or a resin subjected to acid modification as the adhesive resin layer.

  Thus, the adhesion between the FRP member and the metal member can be improved by bonding the FRP member to the metal member using the above-described adhesive resin layer. If it does so, the deformation | transformation followable | trackability of an FRP member when a load is input with respect to a metal member can be improved. In this case, the effect of the FRP member on the deformed body of the metal member can be more reliably exhibited.

  In addition, the form of the adhesive resin composition used for forming the adhesive resin layer can be, for example, a liquid such as powder or varnish, or a solid such as a film.

  Moreover, you may mix | blend a crosslinking curable resin and a crosslinking agent with an adhesive resin composition, and may form a crosslinkable adhesive resin composition. Thereby, since the heat resistance of the adhesive resin composition is improved, application under a high temperature environment becomes possible. As the cross-linking curable resin, for example, a bifunctional or higher functional epoxy resin or a crystalline epoxy resin can be used. Moreover, an amine, an acid anhydride, etc. can be used as a crosslinking agent. Moreover, various additives, such as various rubber | gum, an inorganic filler, a solvent, may be mix | blended with the adhesive resin composition in the range which does not impair the adhesiveness and physical property.

  The compounding of the FRP member into the metal member can be realized by various methods. For example, it can be obtained by adhering an FRP forming prepreg which is an FRP member or an FRP molding prepreg thereof and a metal member with the above-described adhesive resin composition, and solidifying (or curing) the adhesive resin composition. . In this case, for example, the FRP member and the metal member can be combined by performing thermocompression bonding.

  The above-mentioned adhesion of FRP or FRP molding prepreg to a metal member can be performed before molding, during molding, or after molding. For example, after forming a metal material as a workpiece into a metal member, FRP or FRP molding prepreg may be bonded to the metal member. Alternatively, after FRP or FRP molding prepreg is bonded to the workpiece by thermocompression bonding, the workpiece to which the FRP member is bonded may be molded to obtain a composite metal member. If the matrix resin of the FRP member is a thermoplastic resin, it is possible to perform a bending process or the like on the portion to which the FRP member is bonded. In addition, when the matrix resin of the FRP member is a thermoplastic resin, composite batch molding in which the thermocompression bonding step and the molding step are integrated may be performed.

  In addition, the joining method of a FRP member and a metal member is not restricted to the adhesion | attachment by the adhesive resin layer mentioned above. For example, the FRP member and the metal member may be mechanically joined. More specifically, a fastening hole is formed at a position corresponding to each of the FRP member and the metal member, and these are fastened through the hole by a fastening means such as a bolt or a rivet. The member may be joined. In addition, the FRP member and the metal member may be joined by a known joining means. Further, the FRP member and the metal member may be joined in a composite manner by a plurality of joining means. For example, the adhesion by the adhesive resin layer and the fastening by the fastening means may be used in combination.

<Metal member and its surface treatment>
The metal member according to the present invention may be plated. Thereby, corrosion resistance improves. In particular, it is more suitable when the metal member is a steel material. The type of plating is not particularly limited, and known plating can be used. For example, as a galvanized steel sheet (steel material), a galvanized steel sheet, a galvannealed steel sheet, a Zn-Al-Mg alloy-plated steel sheet, an aluminum-plated steel sheet, an electrogalvanized steel sheet, an electric Zn-Ni alloy-plated steel sheet, etc. Can be used.

  Moreover, the metal member may be coated with a film called chemical conversion treatment on the surface. Thereby, corrosion resistance improves more. As the chemical conversion treatment, a generally known chemical conversion treatment can be used. For example, as the chemical conversion treatment, zinc phosphate treatment, chromate treatment, chromate-free treatment or the like can be used. Further, the film may be a known resin film.

  In addition, the metal member may be one that has been generally painted. Thereby, corrosion resistance improves more. As the coating, a known resin can be used. For example, as a coating, an epoxy resin, a urethane resin, an acrylic resin, a polyester resin, or a fluorine resin can be used as a main resin. Moreover, generally well-known pigment may be added to the coating as needed. The coating may be a clear coating to which no pigment is added. Such coating may be applied to the metal member in advance before the FRP member is combined, or may be applied to the metal member after the FRP member is combined. Alternatively, the FRP member may be combined after the metal member has been painted in advance, and then painted. The paint used for painting may be a solvent-based paint, a water-based paint, a powder paint, or the like. In general, a known method can be applied as a method of painting. For example, electrodeposition coating, spray coating, electrostatic coating, immersion coating, or the like can be used as a coating method. Since electrodeposition coating is suitable for coating the end face and gap portion of a metal member, it is excellent in corrosion resistance after coating. Moreover, coating film adhesion improves by performing generally well-known chemical conversion treatments, such as a zinc phosphate process and a zirconia process, on the surface of a metal member before coating.

  The reinforcing member 4 of the present embodiment has a multi-layer structure having a plurality of layers having different fiber directions. As shown in FIG. 3, the reinforcing member 4 of the present embodiment has a layer in which the fiber direction (the direction of the dashed arrow in FIG. 3) is parallel to the longitudinal direction, that is, the angle formed between the longitudinal direction and the fiber direction is 0. And a layer perpendicular to the longitudinal direction, that is, a layer having an angle of 90 ° between the longitudinal direction and the fiber direction. Since the reinforcing member 4 has a plurality of layers having different fiber directions as described above, the energy absorption performance can be further improved. In addition, the fiber direction of each layer when the reinforcing member 4 has a multilayer structure is not particularly limited. Further, in the case of a multilayer structure including a layer having a fiber direction of 90 ° with respect to the longitudinal direction of the hollow member 10, 25% or more of all the layers are preferably layers having a fiber direction of 90 °. . Thereby, energy absorption performance can be improved effectively. The reinforcing member 4 may have three or more layers having different fiber directions. Further, the reinforcing member 4 may have a single-layer structure depending on the shape of the hollow member 10, required energy absorption performance, weight limitation, and the like. Further, the reinforcing member 4 may be a sheet forming compound (SMC) obtained by impregnating a discontinuous fiber into a matrix resin and processing it into a sheet shape. Industrially, when the fiber direction is aligned in one direction, the actual fiber direction distribution of the fiber is distributed within a range of −5 ° to 5 ° with respect to the one direction. Even in such an industrially distributed state, it may be determined that the mechanical properties are substantially the same as compared to a case where all fiber directions are ideally aligned in one direction. Further, the fiber direction distribution in the reinforcing member can be identified by observing with a microfocus X-ray computed tomograph (CT) system and computer analysis of the obtained three-dimensional image.

  As shown in FIG. 4, the hollow member 10 of the present embodiment is provided with bent portions 5A and 5B in a part in the longitudinal direction. The bent portion 5 is a portion having a curvature in the central axis C <b> 1 formed by the center of gravity of the cross section of the hollow member 10.

  Such a bent part 5 and the peripheral part of the bent part 5 are examples of the bending induction part 7 (7A, 7B). The hollow member 10 provided with the bent portion 5 is obtained by, for example, performing press molding so that the bent portion 5 is provided on the first structural member 2 and the second structural member 3 and assembling these structural members 2 and 3. It is done. The bent portion 5 is appropriately provided according to the structure of the vehicle to which the frame 1 is applied. The number of the bent portions 5 provided in the hollow member 10 is not particularly limited, and is appropriately determined according to the structure of the vehicle as described above. That is, there is a case where the bent portion 5 is not provided in the hollow member 10.

  When the bending induction part 7 is formed in the hollow member 10, a bending deformation occurs in the bending induction part 7 due to a collision from the longitudinal direction. For example, at least one of the radius of curvature RA of the bent portion 5A and the radius of curvature RB of the bent portion 5B or at least one of them is bent when a collision load is input. The energy required for this bending deformation is supplied from the energy caused by the collision. That is, collision energy can be absorbed by bending deformation of the hollow member 10. By providing the bending induction portion 7 in the hollow member 10, the bending start point of the hollow member 10 generated by the collision can be set. Therefore, the impact on the cabin structure due to the unexpected bending of the hollow member 10 can be avoided, so that the safety of the passenger boarding the cabin can be ensured.

  In addition, the bending induction part 7 which concerns on this embodiment is not limited to the part containing the bending part 5 shown in FIG. A specific example of the bending induction part 7 will be described later.

(Arrangement of reinforcing members)
As shown in FIG. 4, the hollow member 10 of the present embodiment includes a bent portion 5 </ b> A that bends in the direction in which the top wall portion 2 a is bent inside, and a bent portion that is bent in the direction in which the bottom wall portion 3 a is bent inside. 5B is provided. As described above, the bent portions 5A and 5B and the peripheral portions of the bent portions 5A and 5B are the bending induction portions 7A and 7B of the hollow member 10 of the present embodiment. The reinforcing member 4 of the present embodiment is joined to the inner surfaces of the front and rear sides of the bending induction portions 7A and 7B in the longitudinal direction of the hollow member 10. In other words, when the portion adjacent to the bending induction portion 7 is referred to as the adjacent portion 8 (8A to 8C), the reinforcing member 4A is joined to the inner surface of the adjacent portion 8A on the front side in the longitudinal direction with respect to the bending induction portion 7A. ing. The reinforcing member 4B is joined to the inner surface of the adjacent portion 8B on the rear side in the longitudinal direction with respect to the bending induction portion 7A. In the case of the hollow member 10 of the present embodiment, it can be said that the reinforcing member 4B is joined to the inner surface of the adjacent portion 8B on the front side in the longitudinal direction with respect to the bending induction portion 7B. The reinforcing member 4C is joined to the inner surface of the adjacent portion 8C on the rear side in the longitudinal direction with respect to the bending induction portion 7B. In addition, arrangement | positioning of the reinforcement member 4 is not limited to the inner surface of the hollow member 10, You may arrange | position to the outer surface side. Regarding the arrangement of the reinforcing member 4 in the following description, the reinforcing member 4 may be arranged on the outer surface side as long as the hollow member 10 can be arranged on the outer surface side. Moreover, although the joining method of the reinforcement member 4 with respect to the hollow member 10 is not specifically limited, For example, it is preferable to join both the members 10 and 4 using an adhesive agent.

  The range of the bending induction part 7 of this embodiment is defined as follows. As shown in FIG. 6, the above-mentioned central axis C1 is composed of a straight line part and an arc part, and the bent part 5A is an arc part having a radius of curvature RA connected to the straight line part on the central axis C1. Here, let P be the intersection between the bisector of the corner of the arc connected to the straight line on the central axis C1 and the arc. In this case, the range of the bent portion 5A is from the position of the length L forward in the direction of the central axis C1 starting from the point P to the position of the length L rearward in the direction of the central axis C1 starting from the point P. It is an area. Since the buckling that occurs at the time of collision of the hollow member 10 has a correlation with the cross-sectional size of the hollow member, the length 2L in the present specification is preferably the width of the hollow member 10 in the bending direction. In the case of the hollow member 10 of the present embodiment, since the Y-axis direction is the bending direction, the distance between the top wall portion 2a and the bottom wall portion 3a shown in FIG. 2 is the width W of the hollow member 10, and It is better if the length 2L is the width W. In addition, the range of the bending induction part 7 is defined by the same view also about the bending part 5B.

  As shown in FIG. 2, the reinforcing member 4 of this embodiment is joined to the entire inner circumference of the hollow member 10. Specifically, the top wall 2a of the hollow member 10, a pair of side walls 2b, a bottom wall 3a, a corner 11a that is a portion between the top wall 2a and the pair of side walls 2b, and a pair of side walls It is joined to the inner surface of the corner part 11b which is a part between 2b and the bottom wall part 3a. The length of the reinforcing member 4 in the longitudinal direction of the hollow member 10 is appropriately changed according to the shape of the frame 1, required energy absorption performance, weight restriction, etc. 7 or more of the range of 7 is preferable. In other words, it is preferable that the length of the reinforcing member 4 is ½ or more of the width W in the bending direction of the hollow member 10. Further, the thickness of the reinforcing member 4 is appropriately changed according to the shape of the frame 1, required energy absorption performance, weight limit, and the like.

  The frame 1 of the present embodiment is configured as described above. In such a frame 1, for example, when a high load is input from the front in the longitudinal direction, the bending portion 5 undergoes bending deformation and buckles. Therefore, even if the reinforcing member 4 made of CFRP is joined to the bent portion 5, since the ductility of CFRP is extremely low, the instantaneous fracture occurs and the effect as a reinforcing member is not exhibited at all. On the other hand, in the adjacent portion 8 adjacent to the bent portion 5, out-of-plane deformation occurs following the deformation of the bent portion 5, but in the frame 1 of the present embodiment, the reinforcing member 4 is joined to the hollow member 10. As a result, the rigidity of the adjacent portion 8 is improved, and the out-of-plane deformation in the adjacent portion 8 can be suppressed. Accordingly, in the adjacent portion 8, the deformation proceeds while generating a higher reaction force, so that the energy absorption performance of the frame 1 is improved. Further, although the ductility of CFRP is extremely low, the adjacent portion 8 does not instantly undergo large deformation, and since the deformation progresses gradually, the CFRP also absorbs energy while gradually breaking through the later stages of deformation. Is possible. Therefore, in the frame 1 of the present embodiment, it is possible to maintain or improve the energy absorption performance while reducing the weight.

<4. Example of arrangement of reinforcing members>
As mentioned above, although arrangement | positioning of the reinforcement member 4 which concerns on this embodiment was demonstrated, arrangement | positioning of the reinforcement member 4 is not limited to the example shown in FIG. Hereinafter, other arrangement examples of the reinforcing member 4 will be described with reference to FIGS. 7, 9, and 12, the first structural member 2 is not shown for convenience of explanation regarding the arrangement of the reinforcing member 4.

(First arrangement example)
As shown in FIGS. 7 and 8, in this arrangement example, the shape of the reinforcing member 4 is U-shaped in the cross section perpendicular to the longitudinal direction of the hollow member 10, and the reinforcing member 4 is located on the upper side of the hollow member 10. The side wall 2b and the lower side wall 2b are respectively joined to the inner surfaces. More specifically, the reinforcing member 4 is joined to the side walls 2b, the corners 11a and 11b, a part of the top wall 2a, and a part of the inner surface of the bottom wall 3a. Even when the reinforcing member 4 is provided in such an arrangement, the out-of-plane deformation of the adjacent portion 8 adjacent to the bent portion 5 can be suppressed, and the energy absorption performance can be improved.

  Note that the length of the tip portion 4a of the U-shaped reinforcing member 4 is the length of the wall portion (the top wall portion 2a or the bottom wall portion 3a in this arrangement example) to which the tip portion 4a is joined (one R). The length from the stop to the other R stop) is preferably 1/5 or more. Thereby, energy absorption performance can be improved effectively. Moreover, when arrange | positioning the U-shaped reinforcement member 4 to a pair of wall part which opposes, it is preferable to cover the whole inner surface of the wall part (side wall part 2b in this arrangement example) parallel to a bending direction. Thereby, energy absorption performance can be improved effectively.

(Second arrangement example)
As shown in FIGS. 9 to 11, in this arrangement example, the reinforcing member 4 is added to the entire inner periphery of the adjacent portions 8 </ b> A to 8 </ b> C, and corner portions 11 a and 11 b of the hollow member 10 other than the adjacent portions 8 </ b> A to 8 </ b> C. It is joined to. For example, in the case of a frontal collision of an automobile, the collision energy is absorbed by buckling in order from the front part of the vehicle, but if a member with low proof stress (initial reaction force) is interposed behind, The buckling of the rear member occurs before the member buckles, and the energy absorption performance inherent in the vehicle as a whole may not be exhibited. On the other hand, in this arrangement example, the reinforcing member 4 is joined to the corner portions 11a and 11b of the hollow member 10 other than the adjacent portions 8A to 8C, so that an axial load is input to the frame 1. The yield strength (initial reaction force) of the frame 1 can be increased. As a result, the energy absorption performance inherent in the entire vehicle can be easily exhibited.

(Third arrangement example)
As shown in FIGS. 12 to 14, in the present arrangement example, the reinforcing member 4 having a U-shaped cross section is joined to the adjacent portions 8 </ b> A to 8 </ b> C, and corner portions are provided in portions other than the adjacent portions 8 </ b> A to 8 </ b> C. The reinforcing member 4 is joined only to 11a and 11b. Also in this arrangement example, the proof stress (initial reaction force) of the frame 1 can be increased. Thereby, while being able to make it easy to exhibit the energy absorption performance which the vehicle originally has, it is excellent in mass efficiency and can improve energy absorption performance.

  The arrangement example of the reinforcing member 4 has been described above, but the arrangement of the reinforcing member 4 is appropriately changed depending on the shape of the frame 1, required energy absorption performance, weight limitation, and the like.

<5. Example of bending induction section>
Next, an example of the bending induction part 7 provided in the hollow member 10 will be described. In the above embodiment, the example in which the bending portion 5 is provided in the bending induction portion 7 has been described, but the present invention is not limited to such an example. For example, in a hollow member that does not have a bent portion (for example, a hollow member that extends substantially linearly in the longitudinal direction), a portion that includes a hole, a concave portion, a convex portion, a plate thickness changing portion, a different strength portion, and the like However, the function as the bending induction part 7 is implement | achieved. A portion where any of the hole, the concave portion, the convex portion, and the plate thickness changing portion is provided is a portion where the section modulus of the hollow member 10 changes in the longitudinal direction of the hollow member 10. In a portion where the section modulus changes in the longitudinal direction of the hollow member 10, the bending stress generated in the hollow member 10 is changed by the same bending moment, so that bending of the hollow member 10 is induced in the portion. More specifically, since the bending stress at the portion of the hollow member 10 having a relatively small section modulus in the longitudinal direction is relatively large, the portion is bent. Moreover, about the part with a comparatively large section modulus among the hollow members 10 in a longitudinal direction, the section coefficient of the part including the area | region in the front and back of the longitudinal direction of the hollow member 10 of the said part becomes relatively small. Therefore, bending occurs at a boundary portion between the region and the portion having a relatively large section modulus.

  Further, the different strength portion is a portion where the yield strength of the hollow member 10 changes in the longitudinal direction of the hollow member 10. In the portion where the yield strength changes in the longitudinal direction of the hollow member 10, plastic deformation of the hollow member 10 in the portion is induced. For example, in a portion where the yield strength is relatively low in the hollow member 10 in the longitudinal direction, plastic deformation in the portion first occurs in the hollow member 10, so that bending occurs in the portion. Moreover, about the part where yield strength is comparatively large among the hollow members 10 in a longitudinal direction, the yield strength of the part including the area | region in the longitudinal direction of the hollow member 10 of the said part becomes comparatively small. Therefore, bending occurs at a boundary portion between the region and the portion having a relatively high yield strength.

  Further, in the hollow member that does not have a bent portion, even if there is no portion including a hole, a concave portion, a convex portion, a plate thickness changing portion, a different strength portion, etc. that realize the function as the bending induction portion 7 described above, When the direction of load input applied to the hollow member can be specified to some extent, there is a region in the hollow member where the bending moment is maximized due to the influence of the restraint of the peripheral member joined to the hollow member, and the bending in that region Arise. Therefore, when the bending moment generated in the hollow member can be specified, the region where the bending moment is maximized also has a function as the bending inducing portion 7.

  Hereinafter, a specific example of the bending induction portion 7 provided in the hollow member 10 will be described.

(Hole)
In the example shown in FIGS. 15 and 16, a hole 50 is provided in the top wall 2a. The section modulus of the hollow member 10A in the portion where the hole 50 is provided is lower than the section modulus of the portion before and after the portion where the hole 50 of the hollow member 10A is provided. Therefore, when the collision load F is input to the hollow member 10 </ b> A, the frame 1 bends so that the hole 50 is on the bending inner side in the portion where the hole 50 is provided.

  In this case, the range of the bending induction part 7 starts from the hole center of the hole part 50 from the position of the length L in the longitudinal direction of the hollow member 10A starting from the hole center of the hole part 50 as shown in FIG. It becomes an area | region to the position of the length L of the longitudinal direction back of 10 A of hollow members made. The length L is equal to the width W of the hollow member 10 shown in FIG. The reinforcing member 4 is joined to a portion adjacent to the bending inducing portion 7 to suppress out-of-plane deformation of the frame 1 when buckling occurs in the vicinity of the hole 50 due to the input of the collision load F. The energy absorption performance of the frame 1 can be improved.

  Moreover, about the shape and arrangement | positioning of a hole part, it is not restricted to the example mentioned above. For example, as shown in FIG. 17, a plurality of holes 50b may be provided in the top wall 2a. In this case, when the collision load is input, the hollow member 10A is easily bent and deformed toward the top wall portion 2a with the hole 50b serving as a starting point of bending.

  Moreover, as shown in FIG. 18, the hole part 50c extended in the direction crossing the longitudinal direction of 10 A of hollow members may be provided in the top wall part 2a. In this case, when the collision load is input, the hollow member 10A is bent and deformed toward the top wall portion 2a with the hole 50c serving as a starting point of bending. Note that the shape of the hole 50c is not limited to the rounded rectangle shown in FIG.

  In addition, the direction crossing the longitudinal direction of the hollow member 10A described above is not limited to the direction orthogonal to the longitudinal direction of the hollow member 10A, but in the surface of the portion where the hole 50 is provided, the longitudinal direction of the hollow member 10A It is preferable that the angle formed by the transverse direction is not less than 45 degrees and not more than 90 degrees. Thereby, stable bending deformation can be induced.

  Moreover, the part in which the hole part 50 is provided is not restricted to the top wall part 2a. For example, the hole part 50 may be provided in the side wall part 2b or the bottom wall part 3a. Moreover, it is preferable that the hole part 50 etc. are not provided in the part facing the part in which the hole part 50 was provided. For example, when the hole part 50 is provided in the top wall part 2a, it is preferable that the bottom wall part 3a is not provided with a part that induces bending deformation of another hole part 50. This is because a bending deformation is induced on the side where the hole 50 is provided when a collision load is input.

  Moreover, as shown in FIG. 19, the hole part 50d may be provided in the ridgeline part 2d. As a result, the section modulus of the portion of the hollow member 10A in which the hole 50d is provided in the longitudinal direction is remarkably reduced, so that bending deformation starting from the portion in which the hole 50d is provided is more reliably induced. can do.

(Concave)
As shown in FIGS. 20 and 21, a bead portion 51 is provided on the top wall portion 2a. The bead part 51 is an example of a recessed part in the present embodiment. The section modulus of the hollow member 10B in the portion where the bead portion 51 is provided is lower than the section modulus of the portion before and after the portion where the bead portion 51 of the hollow member 10B is provided. Therefore, when the collision load F shown in FIG. 20 is input to the hollow member 10B, the frame 1 bends at the portion where the bead portion 51 is provided so that the bead portion 51 is on the bending inner side.

  In this case, as shown in FIG. 20, the range of the bending inducing portion 7 starts from the deepest position of the concave portion from the position of the length L in the longitudinal direction of the hollow member 10B starting from the deepest position of the concave portion. It becomes an area | region to the position of the length L of the longitudinal direction back of the hollow member 10B. The length L is equal to the width W of the hollow member 10 shown in FIG. The reinforcing member 4 is joined to a portion adjacent to the bending inducing portion 7 to suppress out-of-plane deformation of the frame 1 when buckling occurs in the vicinity of the bead portion 51 due to the input of the collision load F. The energy absorption performance of the frame 1 can be improved.

  In addition, about the shape and arrangement | positioning of a recessed part, it is not restricted to the example mentioned above. The concave portion referred to here means a hollow portion such as emboss or bead provided in the top wall portion 2a of the hollow member 10B.

  As shown in FIG. 22, a plurality of recesses 51b may be provided in the top wall 2a. In this case, for example, the plurality of recesses 51b may be provided side by side in a direction crossing the longitudinal direction of the hollow member 10B. In this case, when the collision load is input, the hollow member 10B is easily bent and deformed toward the top wall portion 2a with the plurality of concave portions 51b serving as starting points of bending.

  Moreover, as shown in FIG. 23, the bead part 51c extended in the direction crossing the longitudinal direction of the hollow member 10B may be provided in the top wall part 2a. In this case, when the collision load is input, the hollow member 10B is bent and deformed toward the top wall portion 2a with the bead portion 51c serving as a starting point of bending. In addition, the shape of the bead part 51c is not limited to the rounded rectangle shown in FIG.

  In addition, the direction which crosses the longitudinal direction of the hollow member 10B mentioned above is not limited to the direction orthogonal to the longitudinal direction of the hollow member 10B. For example, the angle formed by the longitudinal direction of the hollow member 10B and the transverse direction may be 45 degrees or more and 90 degrees or less on the surface of the portion where the recess 51 is provided.

  Moreover, the part in which the recessed part 51 is provided is not restricted to the top wall part 2a. For example, the recessed part 51 may be provided in the side wall part 2b or the bottom wall part 3a. Moreover, it is preferable that the recessed part 51 etc. are not provided in the part facing the part in which the recessed part 51 was provided. For example, when the recessed part 51 is provided in the top wall part 2a, it is preferable that the part which induces the bending deformation of another recessed part 51 is not provided in the bottom wall part 3a. This is because bending deformation is induced on the side where the recess 51 is provided when a collision load is input.

  Moreover, as shown in FIG. 24, the recessed part 51d may be provided in the ridgeline part 2d. As a result, the section modulus of the portion of the hollow member 10B in which the recess 51d is provided in the longitudinal direction changes remarkably, so that bending deformation starting from the portion in which the recess 51d is provided is more reliably induced. Can do.

When the recess 51 as described above is provided, the form of the recess 51 is not particularly limited, but the recess 51 preferably has the following form. For example, when the hollow member 10B is formed of a high-strength steel plate, from the viewpoint of formability, as shown in FIG. 25, the depth D _{d of the} recess 51 (the surface 511 of the portion provided with the recess 51 and the recess 51 The length in the direction perpendicular to the plane between the bottom 512 and the bottom 512 is preferably at least three times the plate thickness of the hollow member 10B. The distance L _d of the edge 513 between the recesses 51 in the longitudinal direction of the hollow member 10B is preferably 50mm or less.

As shown in FIG. 26, recesses 51e and 51f extending in the longitudinal direction of the hollow member 10B may be provided side by side along the longitudinal direction of the hollow member 10B. In this case, in the hollow member 10B, bending occurs in a portion 510 between the recess 51e and the recess 51f in the longitudinal direction. That is, in the hollow member 10B, the portion where the recesses 51e and 51f are provided and the portion 510 between the recess 51e and the recess 51f have different section coefficients, so that when the collision load is input, the portion 510 is bent. As a starting point, bending deformation occurs. In this case, the range of the bending inducing portion 7 is a longitudinal length starting from the central position of the portion 510 from the position of the length L in the longitudinal direction starting from the central position of the portion 510 in the longitudinal direction of the hollow member 10B. It becomes an area up to the position of the length L in the rear direction. Note that in this case, if the hollow member 10B is made of a high strength steel sheet, from the viewpoint of moldability, the recess 51e, the depth D _d of 51f, the plate thickness of the hollow member 10B is three times or more Is preferred. Further, the portion 510 may be formed with a concave portion, a convex portion described later, a thin portion, a different strength portion, or the like.

  As shown in FIG. 26, the recess 51e and the recess 51f are not necessarily arranged in series. Moreover, the recessed part 51e and the recessed part 51f do not necessarily need to extend in the longitudinal direction of the hollow member 10B. For example, in the surface of the portion where the recess 51e and the recess 51f are provided, the angle formed by the longitudinal direction of the hollow member 10B and the extending direction of the recess 51e and the recess 51f may be 0 degree or greater and 45 degrees or less.

(Convex)
As shown in FIGS. 27 and 28, the top wall 2a is provided with a convex portion 52. The section modulus of the hollow member 10C in the portion where the convex portion 52 is provided is higher than the section modulus of the portion in the longitudinal direction of the portion where the convex portion 52 of the hollow member 10C is provided. Therefore, when the collision load F is input to the hollow member 10C, the convex portion 52 is bent inward in the region 6a or 6b before and after the convex portion 52 in the longitudinal direction of the hollow member 10C where the section modulus is the lowest. Bend to be. These regions 6a and 6b are regions where the change in the section modulus of the hollow member 10C occurs in the X-axis direction.

  In this case, the range of the bending induction portion 7 starts from the top portion of the convex portion 52 from the position of the length L in the longitudinal direction of the hollow member 10C starting from the top portion of the convex portion 52 as shown in FIG. It becomes an area | region to the position of the length L of the longitudinal direction back of 10 C of hollow members. The length L is equal to the width W of the hollow member 10 shown in FIG. The reinforcing member 4 is joined to a portion adjacent to the bending induction portion 7 to suppress out-of-plane deformation of the frame 1 when buckling occurs in the vicinity of the convex portion due to the input of the collision load F. The energy absorption performance of the frame 1 can be improved.

  In the example shown in FIGS. 27 and 28, the convex portion 52 is provided on the top wall 2a. However, the present invention is not limited to such an example. For example, the convex part 52 may be provided in the side wall part 2b or the bottom wall part 3a. More specifically, when the convex portion 52 is provided on the pair of side wall portions 2b and the bottom wall portion 3a on the same cross section in a part in the longitudinal direction of the hollow member 10, the cross section in the longitudinal direction of the hollow member 10 is provided. Since the coefficient changes in the portion where the convex portion 52 is provided, the bending of the frame 1 may occur in the portion where the convex portion 52 is provided. Therefore, even in this case, the portion including the convex portion 52 becomes the bending induction portion 7.

  Moreover, about the shape and arrangement | positioning of a convex part, it is not restricted to the example mentioned above. A convex part here is implement | achieved by the process etc. of the hollow member 10, for example. That is, the convex portion may be provided by deforming a part of the steel plate constituting the hollow member 10C.

  Moreover, as shown in FIG. 29, the some convex part 52b may be provided in the top wall part 2a. In this case, for example, the plurality of convex portions 52b may be provided side by side in a direction crossing the longitudinal direction of the hollow member 10C. In this case, when a collision load is input, the hollow member 10C is easily bent and deformed toward the top wall portion 2a with any one of the regions before and after the plurality of convex portions 52b in the longitudinal direction of the hollow member 10C as a starting point of bending. .

  Moreover, as shown in FIG. 30, the convex part 52c extended in the direction crossing the longitudinal direction of 10 C of hollow members may be provided in the top wall part 2a. In this case, when a collision load is input, the hollow member 10C is bent and deformed toward the top wall portion 2a with one of the regions before and after the convex portion 52c in the longitudinal direction of the hollow member 10C as a starting point of bending. In addition, the shape of the convex part 52c is not limited to the rounded rectangle shown in FIG.

  In addition, the direction which crosses the longitudinal direction of 10 C of hollow members mentioned above is not limited to the direction orthogonal to the longitudinal direction of 10 C of hollow members. For example, the angle formed by the longitudinal direction of the hollow member 10C and the transverse direction may be 45 degrees or more and 90 degrees or less on the surface of the portion where the convex portion 52 is provided.

  Moreover, the part in which the convex part 52 is provided is not restricted to the top wall part 2a. For example, the convex part 52 may be provided in the side wall part 2b or the bottom wall part 3a. Moreover, it is preferable that the convex part 52 etc. are not provided in the part facing the part in which the convex part 52 was provided. For example, when the convex part 52 is provided in the top wall part 2a, it is preferable that the bottom wall part 3a is not provided with a part that induces bending deformation such as another convex part 52 or the like. This is because bending deformation is induced on the side where the convex portion 52 is provided when the collision load is input.

  Moreover, as shown in FIG. 31, the convex part 52d may be provided in the ridgeline part 2d. As a result, the section modulus of the portion of the hollow member 10C where the convex portion 52d is provided in the longitudinal direction changes remarkably, so that bending deformation with the portion where the convex portion 52d is provided as the starting point of bending is more reliably induced. can do.

When providing the convex part 52 as above-mentioned, although the form of the convex part 52 is not specifically limited, It is preferable that the convex part 52 has a form shown below. For example, when the hollow member 10C is formed of a high-strength steel plate, from the viewpoint of formability, as shown in FIG. 32, the height H _{d of the} convex portion 52 (the surface 521 of the portion where the convex portion 52 is provided and the convex The length in the direction orthogonal to the plane between the top 522 of the part 52 is preferably at least three times the plate thickness of the hollow member 10C. The distance L _d between the edge 523 of the convex portion 52 in the longitudinal direction of the hollow member 10C is preferably 50mm or less.

As shown in FIG. 33, convex portions 52e and 52f extending in the longitudinal direction of the hollow member 10C may be provided side by side along the longitudinal direction of the hollow member 10C. In this case, in the hollow member 10C, bending occurs at a portion 520 between the convex portion 52e and the convex portion 52f in the longitudinal direction. That is, in the hollow member 10C, the section coefficient is different between the portion provided with the convex portions 52e and 52f and the portion 520 between the convex portion 52e and the convex portion 52f. Bending deformation occurs with 520 as the starting point of bending. In this case, the range of the bending inducing portion 7 is a longitudinal length starting from the central position of the portion 520 from the position of the length L in the longitudinal direction starting from the central position of the portion 520 in the longitudinal direction of the hollow member 10C. It becomes an area up to the position of the length L in the rear direction. Even in this case, when the hollow member 10C is formed of a high-strength steel plate, from the viewpoint of formability, the heights (H _d ) of the protrusions 52e and 52f are three times or more the plate thickness of the hollow member 10C. It is preferable that Moreover, the said recessed part, the convex part, the thin part mentioned later, or a different strength part etc. may be formed in the said part 520. FIG.

  In addition, the convex part 52e and the convex part 52f do not necessarily need to be located in series as shown in FIG. Moreover, the convex part 52e and the convex part 52f do not necessarily extend in the longitudinal direction of the hollow member 10C. For example, the angle formed by the longitudinal direction of the hollow member 10C and the extending direction of the convex portions 52e and 52f on the surface of the portion where the convex portions 52e and 52f are provided may be 0 degree or more and 45 degrees or less. That's fine.

(Thickness change / thin wall)
In addition, a plate thickness changing portion may be provided on the top wall portion 2a as a configuration for realizing the bending induction portion 7. Here, the plate thickness changing portion means a portion where the plate thickness changes in the longitudinal direction of the hollow member 10D. As shown in FIG. 34, the hollow member 10D includes a first plate thickness portion 111 and a second plate thickness portion 112. The first plate thickness portion 111 is provided on the end side of the hollow member 10D, and the second plate thickness portion 112 is provided continuously with the first plate thickness portion 111 along the longitudinal direction of the hollow member 10D. The plate thickness of the steel plate is different between the first plate thickness portion 111 and the second plate thickness portion 112. The magnitude relation of the plate thickness is not particularly limited, but it is preferable that the plate thickness of the second plate thickness portion 112 is larger than the plate thickness of the first plate thickness portion 111 from the viewpoint of ensuring the bending rigidity of the entire hollow member 10D. .

  In this case, as shown in FIG. 34, the boundary portion between the first plate thickness portion 111 and the second plate thickness portion 112 becomes the plate thickness changing portion 113. In the plate thickness changing portion 113, the section modulus in the longitudinal direction of the hollow member 10D changes. That is, the portion including the plate thickness changing portion 113 corresponds to the bending induction portion 7. Therefore, when a collision load is input to the hollow member 10 </ b> D, the frame 1 bends at the plate thickness changing portion 113.

  In this case, the range of the bending inducing portion 7 is the longitudinal direction of the hollow member 10D starting from the plate thickness changing portion 113 from the position of the length L at the front in the longitudinal direction of the hollow member 10D starting from the plate thickness changing portion 113. It becomes an area up to the position of the rear length L. The length L is equal to the width W of the hollow member 10 shown in FIG. The reinforcing member 4 is joined to a portion adjacent to the bending inducing portion 7 so that when the buckling occurs in the vicinity of the plate thickness changing portion 113 due to the input of the collision load F, the frame 1 is deformed out of plane. Therefore, the energy absorption performance of the frame 1 can be improved.

  Moreover, the bending induction part 7 may be implement | achieved by the thin part, for example. As shown in FIG. 35, the top wall 2a is provided with a thin portion 114 having a relatively smaller plate thickness than other portions in the longitudinal direction of the hollow member 10D. The section modulus of the hollow member 10 in the portion including the thin portion 114 is lower than the section modulus of the hollow member 10 in the portion of the hollow member 10 in the longitudinal direction before and after the portion where the thin portion 114 is provided. That is, the portion including the thin portion 114 in the hollow member 10 </ b> D corresponds to the bending induction portion 7. Therefore, when a collision load is input to the hollow member 10D, the frame 1 bends at the portion where the thin portion is provided so that the thin portion is on the bending inner side.

  In this case, the range of the bending inducing portion 7 is the longitudinal length starting from the central position of the thin portion 114 from the position of the length L forward in the longitudinal direction starting from the central position of the thin portion 114 in the longitudinal direction of the hollow member 10. It becomes an area up to the position of the length L in the rear direction. The length L is equal to the width W of the hollow member 10 shown in FIG. The reinforcing member 4 is joined to a portion adjacent to the bending inducing portion 7 to suppress out-of-plane deformation of the frame 1 when buckling occurs in the vicinity of the thin portion 114 due to the input of the collision load F. The energy absorption performance of the frame 1 can be improved.

  The hollow member 10 </ b> D having such a plate thickness changing portion may be formed by a processed plate made of, for example, cutting, pressing, and tailored blank. Such a work plate may be a tailor welded blank (TWB) having a weld line. Moreover, the said to-be-processed board may be the tailor rolled blank (Tailor Rolled Blank; TRB) provided by varying plate | board thickness with a rolling roll. In TWB, the difference thickness at the plate thickness changing portion can be 0.2 mm or more. In TRB, the plate thickness change amount in the plate thickness changing portion per member longitudinal direction can be 0.1 mm / 100 mm or more.

(Different strength part / strength change part)
In the example shown in FIG. 36, a different strength portion 53 is provided on the top wall portion 2a. The different strength portion 53 is provided, for example, by partially performing heat treatment such as welding, quenching, or tempering on the hollow member 10E. The yield strength of the hollow member 10E in the portion where the different strength portion 53 is provided is different from the yield strength of the portion in the longitudinal direction of the portion where the different strength portion 53 of the hollow member 10E is provided. Therefore, when the collision load F shown in FIG. 36 is input to the hollow member 10E, the different strength portion 53 bends in the vicinity of the different strength portion 53 or in the vicinity of the different strength portion 53 so as to be bent inside. This bending is a bending caused by plastic deformation of the different strength portion 53 or a region in the vicinity of the different strength portion 53.

  In this case, the range of the bending inducing portion 7 is the different strength portion in the longitudinal direction of the hollow member 10E from the position of the length L in the longitudinal direction starting from the center position of the different strength portion 53 in the longitudinal direction of the hollow member 10E. This is a region up to the position of the length L at the rear in the longitudinal direction starting from the central position of 53. The length L is equal to the width W of the hollow member 10 shown in FIG. The reinforcing member 4 is joined to a portion adjacent to the bending inducing portion 7 to suppress out-of-plane deformation of the frame 1 when buckling occurs in the vicinity of the different strength portion 53 due to the input of the collision load F. The energy absorption performance of the frame 1 can be improved.

  In the example shown in FIG. 36, the different strength portion 53 is provided on the top wall portion 2a. However, the present invention is not limited to this example. For example, the different strength portion 53 may be provided on the side wall portion 2b or the bottom wall portion 3a. More specifically, when the different strength portion 53 is provided on the pair of side wall portions 2b and the bottom wall portion 3a on the same cross section in a part in the longitudinal direction of the hollow member 10E, the top wall portion on the cross section. The intensity of 2a is the lowest. If it does so, the bending of the flame | frame 1 which makes the top wall part 2a a bending inner side may arise in the different strength part 53. Therefore, even in this case, the portion including the different strength portion 53 becomes the bending induction portion 7.

Moreover, about arrangement | positioning of a different intensity | strength part, it is not restricted to the example mentioned above. The different strength part here is realized by welding or heat treatment to the work plate forming the hollow member 10E.
As shown in FIG. 37, the different strength portion 120 is provided along the circumferential direction of the cross section with respect to the longitudinal direction of the hollow member 10E. Also in this case, the range of the bending inducing portion 7 starts from the central position of the different strength portion 120 from the position of the length L in the longitudinal direction starting from the central position of the different strength portion 120 in the longitudinal direction of the hollow member 10E. It becomes the area | region to the position of the length L of the longitudinal direction back.

  For example, as shown in FIG. 38, the different strength portion may be provided partially on at least one of the wall portions constituting the cross section of the hollow member 10E such as the top wall portion 2a. Even in such a case, when a collision load is input to the hollow member 10E, the frame 1 bends at the portion where the different strength portion 121 is provided so that the different strength portion 121 is bent inside.

  Moreover, the bending induction part 7 may be implement | achieved by the intensity | strength change part, for example. As shown in FIG. 39, the hollow member 10E includes a first strength portion 122 and a second strength portion 123. The first strength portion 122 is provided on the end side of the hollow member 10E, and the second strength portion 123 is provided continuously with the first strength portion 122 along the longitudinal direction of the hollow member 10E. The yield strength of the steel sheet is different between the first strength portion 122 and the second strength portion 123. The magnitude relationship of the yield strength is not particularly limited, but it is preferable that the yield strength of the second strength portion 123 is greater than the yield strength of the first strength portion 122 from the viewpoint of ensuring the bending rigidity of the entire hollow member 10E.

  In this case, the boundary between the first strength portion 122 and the second strength portion 123 becomes the strength changing portion 124. In the strength changing portion 124, the yield strength in the longitudinal direction of the hollow member 10E changes. The range of the bending inducing portion 7 is the longitudinal direction starting from the center position of the strength changing portion 124 from the position of the length L at the front in the longitudinal direction starting from the center position of the strength changing portion 124 in the longitudinal direction of the hollow member 10E. It becomes an area up to the position of the rear length L. The length L is equal to the width W of the hollow member 10 shown in FIG. The reinforcing member 4 is joined to a portion adjacent to the bending inducing portion 7 to suppress out-of-plane deformation of the frame 1 when buckling occurs in the vicinity of the strength changing portion 124 due to the input of the collision load F. The energy absorption performance of the frame 1 can be improved.

(combination)
In the hollow member having a bent portion, a portion for inducing bending such as the hole portion shown in the above example may be further provided in the bent inner portion of the bent portion. As shown in FIG. 40, the hollow member 10 is provided with a bent portion 5A, and a hole portion 54 is provided in a bent inner portion of the top wall portion 2a. The reinforcing member 4 is disposed in close contact with the inner surface of the side wall 2b in the bent portion 5. Thereby, the hollow member 10 can be bent more reliably at the bent portion 5 by the input of the collision load F.

  The bending induction portion 7 is not limited to the example shown in FIG. 40, and the bending of the hollow member 10 in the bending induction portion 7 can be more reliably caused by combining a plurality of examples of the bending induction portion 7 shown above. . For example, the bending inducing part 7 may be realized by a combination of at least two or more of the above-described bent part, concave part, convex part, hole part, plate thickness changing part, thin part, different strength part, and strength changing part.

<6. Example of closed cross-sectional shape of hollow member>
Next, an example of the closed cross-sectional shape of the hollow member 10 will be described. In the example shown in FIG. 41, the closed cross section of the hollow member 10 has a substantially hexagonal shape that is symmetric about the Y axis. Among these, there are four vertices 2d, 2d, 2f, and 2f in the portion of the first structural member 2 that is substantially orthogonal to the Y-axis direction. Here, when the inner angle ang1 of the vertex 2d is smaller than each ang2 among the vertices 2f, the vertex 2d is defined as the ridge line portion 2d. That is, the portion between the pair of ridge lines 2d including the vertices 2f and 2f is defined as the top wall 2a.

  In the example shown in FIG. 42, the first structural member 2 and the second structural member 30 have a hat-shaped cross-sectional shape. That is, the hollow member 10 is formed by two structural members having a hat-shaped cross-sectional shape. In this case, the side wall part 2b of the first structural member 2 and the side wall part 30b of the second structural member 30 are interposed via the ridge line part 2e of the first structural member 2 and the ridge line part 30e of the second structural member 30. The ridgeline portion 2d and the ridgeline portion 30d are defined as one continuous sidewall portion (continuous sidewall portion). That is, the closed cross section of the hollow member 10 is formed by the top wall 2a, the pair of continuous side walls, and the top wall 30a (corresponding to the bottom wall).

  Moreover, the shape of the closed section which the hollow member 10 and the hollow member 10 have is not limited to the example shown in FIG.1, FIG41 and FIG.42. If the shape of the closed cross section of the hollow member 10 is substantially polygonal, and the portions corresponding to the top wall portion, the pair of side wall portions, and the bottom wall portion forming the closed cross section can be defined, the technique according to the present invention is a hollow member. 10 is applicable. For example, the hollow member may have an integral cross section without the flange portion 2c, that is, a prismatic cross section. Moreover, the hollow member which has a closed cross section obtained by overlapping two structural members which have U-shaped cross-sectional shape so that an opening part may oppose may be sufficient. Further, the hollow member may be a hollow member formed by hydroforming or bending a circular pipe.

  As mentioned above, although embodiment of this invention was described in detail, referring an accompanying drawing, this invention is not limited to this example. It is obvious that a person having ordinary knowledge in the technical field to which the present invention pertains can come up with various changes or modifications within the scope of the technical idea described in the claims. Of course, it is understood that these also belong to the technical scope of the present invention.

  In order to evaluate the energy absorption performance of the frame according to the present invention, a collision simulation was performed. The frame of the analysis model used for the simulation is created under the conditions shown in Table 1 below.

  The shapes of the first structural member and the second structural member of the analysis model are the same as those shown in FIG. For this reason, the bending induction part 7 includes a bent part. Further, a CFRP member made of CFRP is used as the reinforcing member. In the structure 1 and the structure 2 shown in Table 1 above, the reinforcing member 4 is not provided. Structure 2 is obtained by increasing the strength and thickness of the hollow member 10 of the structure 1. In the structure 3, as shown in FIGS. 43 and 44, the reinforcing member 4 is joined to the entire inner circumference of the hollow member 10 over the entire longitudinal direction. In the structure 4, as shown in FIGS. 45 and 46, the reinforcing member 4 is joined only to the corner portions 11a and 11b of the hollow member 10 over the entire longitudinal direction. In the structure 5, as shown in FIGS. 47 and 48, the reinforcing member 4 is joined to the entire inner circumference of the bending induction portions 7A and 7B, and the reinforcing member 4 is not joined to the adjacent portions 8A to 8C. The arrangement of the reinforcing member 4 from the structure 6 to the structure 13 has been described in the above embodiment. Structure 2 is 31% lighter than structure 1. In the structures 3 to 13, the arrangement of the reinforcing members may be different, but in order to compare the energy absorption performance under the same weight conditions, each structure is 23% lighter than the structure 1. The plate thickness was changed appropriately.

  The reinforcing member of structure 7 has a single-layer structure in which the angle formed between the longitudinal direction of the hollow member and the fiber direction is 0 °, and the reinforcing member of structure 8 has an angle formed between the longitudinal direction of the hollow member and the fiber direction of 90 °. The reinforcing member of structure 9 has a layer whose angle between the longitudinal direction of the hollow member and the fiber direction is 45 °, and the angle between the longitudinal direction of the empty member and the fiber direction − It has a multilayer structure having a layer of 45 °. The reinforcing member of the structure 10 is a sheet-forming composite material in which discontinuous fibers are impregnated into a matrix resin and processed into a sheet shape. The reinforcing member having a structure other than the structures 7 to 10 includes a layer in which the angle between the longitudinal direction of the hollow member and the fiber direction is 0 °, and a layer in which the angle between the longitudinal direction of the hollow member and the fiber direction is 90 ° And having a multilayer structure.

  The collision simulation was performed by causing an impactor having a mass of 200 kg to collide with the front end of the frame at 12 m / s. And the energy absorption amount at the time of 200 mm stroke of an impactor was computed, and the energy absorption performance of each analysis model was compared.

  FIG. 49 is a diagram showing energy absorption performance of structures 1 to 6. In FIG. 49, the energy absorption amount of each analysis model is normalized by the energy absorption amount of the structure 1. As shown in FIG. 49, the energy absorption performance of the structure 2 that is stronger and thinner than the structure 1 is lower than that of the structure 1. In other words, the plate thickness has been greatly reduced to reduce the weight of the frame, and the strength of the steel plate has been increased to compensate for this, but the energy absorption performance has to be maintained because the strength of the steel plate is insufficient. Is not done. On the other hand, in the structure 6 in which the reinforcing member is joined to the entire inner circumference of the adjacent portion of the hollow member, the energy absorption performance can be improved as compared with the structure 1. As shown in Table 1, since the structure 6 is 23% lighter than the structure 1, the structure 6 can improve the energy absorption performance while reducing the weight of the frame.

  In the structures 3 and 5 in which the reinforcing member is joined to the entire inner periphery of the bending induction portion, the energy absorption performance cannot be sufficiently improved. This is because the CFRP member used as the reinforcing member has a small ductility, and when the reinforcing member is joined to the bending induction portion, the reinforcing member breaks early with buckling of the bending induction portion occurring at the time of collision, It is assumed that the effect of suppressing out-of-plane deformation by the reinforcing member cannot be obtained sufficiently. As for the structure 3, as in the case of the structure 6, although the reinforcing member is joined to the entire inner surface of the adjacent portion, the influence of the breakage of the reinforcing member in the bending induction portion is a portion of the portion joined to the adjacent portion. It is presumed that the effect of suppressing out-of-plane deformation is reduced compared to the structure 6 in which the reinforcing member is joined only to the adjacent portion from the beginning.

  FIG. 50 is a diagram showing the energy absorption performance of Structure 1 and Structures 6-10. In FIG. 50, the energy absorption amount of each analysis model is normalized by the energy absorption amount of the structure 1. In the structures 6 to 10, the joint portions of the reinforcing members are all the same, but the fiber directions are different. As shown in FIG. 50, in the structure 7 having a single-layer structure in which the fiber direction is parallel to the longitudinal direction of the hollow member, the energy absorption performance is lowered with respect to the structure 1. On the other hand, the structure 8 having a single-layer structure in which the fiber direction is perpendicular to the longitudinal direction of the hollow member, the structure 9 having a multilayer structure having layers having different fiber directions, and the structure 10 having discontinuous fibers are equivalent to the structure 1 Energy absorption performance could be obtained. In addition, as shown in the said Table 1, since the weight reduction rate with respect to the structure 1 of the structures 7-10 is 23%, energy absorption performance can be improved by making the thickness of a reinforcement member thick. For this reason, even if it is a frame of the structure 7, energy absorption performance can be maintained or improved, achieving weight reduction with respect to the structure 1. FIG.

  FIG. 51 is a diagram showing the energy absorption performance of Structure 1, Structure 6, and Structures 11-13. In FIG. 51, the energy absorption amount of each analysis model is normalized by the energy absorption amount of the structure 1. As shown in FIG. 51, in the structures 11 to 13, the energy absorption performance can be improved as compared with the structure 1. As shown in Table 1, since the structures 11 to 13 are 23% lighter than the structure 1, the structures 11 to 13 can improve the energy absorption performance while reducing the weight of the frame.

  FIG. 52 is a diagram showing a ratio between the maximum value of the initial reaction force of the structure 6 and the structures 11 to 13 and the maximum value of the initial reaction force of the structure 1. The maximum value of the initial reaction force corresponds to the maximum load before buckling occurs in the initial stage of the collision, that is, the bending induction portion. In the structure 12 and the structure 13 in which the reinforcing member is joined to the inner surface of the corner portion in the portion other than the adjacent portion of the hollow member, the energy absorption performance is largely different from the structure 6 as shown in FIG. 51 described above. Although not generated, the initial reaction force was larger than that of the structure 6 as shown in FIG. Therefore, the reinforcing member is joined to the inner surface of the corner portion in the portion other than the adjacent portion of the hollow member, so that the initial reaction force of the frame at the time of collision can be increased, and the energy absorption performance inherent in the entire vehicle can be exhibited. It can be made easier.

DESCRIPTION OF SYMBOLS 1 Frame 2 1st structural member 2a Top wall part 2b Side wall part 2c Flange part 2d, 2e Edge line part 3, 30 2nd structural member 3a Bottom wall part 30a Top wall part 30b Side wall part 3c, 30c Joint part 30e Ridge line part 4 Reinforcing member 5 Bent part 7 Bending induction part 8 Adjacent part 10 Hollow members 11a, 11b Corner parts 50, 54 Hole part 51 Recessed part 52 Convex part 53 Different strength part

Claims (10)

A top wall portion extending in the longitudinal direction; a pair of side wall portions erected from both ends of the top wall portion; and a bottom wall portion facing the top wall portion; and the top wall portion and the pair of side wall portions A closed cross section is formed by the bottom wall portion, and a metal hollow member having a bending induction portion in a part of the longitudinal direction;
A vehicle structural member comprising: a reinforcing member made of FRP joined to an adjacent portion of the hollow member adjacent to the bending induction portion.   The vehicle structural member according to claim 1, wherein the reinforcing member is joined to the entire circumference of the adjacent portion.   The reinforcing member is joined to both the top wall portion and the bottom wall portion or the pair of side wall portions of the adjacent portion, and the top wall portion and the pair of side wall portions of the adjacent portion. The vehicle structural member according to claim 1, wherein the vehicle structural member is joined to a corner portion between the bottom wall portion and the corner portion between the pair of side wall portions.   The reinforcing member is further provided in a portion other than the adjacent portion of the hollow member, and the reinforcing member is a corner portion between the top wall portion and the pair of side wall portions of a portion other than the adjacent portion, The vehicle structural member according to claim 1, wherein the vehicle structural member is joined to a corner portion between the bottom wall portion and the pair of side wall portions.   The structural member for a vehicle according to any one of claims 1 to 4, wherein the FRP has a plurality of layers having different fiber directions.   The vehicle structural member according to claim 5, wherein the FRP is CFRP or GFRP.   The said bending induction part is a structural member for vehicles as described in any one of Claims 1-6 containing the part from which the section modulus of the said hollow member changes in the said longitudinal direction.   The vehicular structural member according to claim 7, wherein the bending induction part includes a part provided with at least one of a concave part, a convex part, a hole part, a plate thickness changing part, and a thin part.   The vehicle structural member according to claim 8, wherein at least one of the concave portion, the convex portion, and the plate thickness changing portion is arranged in parallel along the longitudinal direction of the hollow member. The said bending induction part is a structural member for vehicles as described in any one of Claims 1-9 containing the part from which the yield strength of the said hollow member changes in the said longitudinal direction.