JPWO2020017645A1 - Vehicle structural member - Google Patents

Abstract

In a structural member for a vehicle, while achieving weight reduction, stable axial crush deformation is generated at the time of a vehicle collision, and energy absorption performance is maintained or improved. A metal hollow member and a plurality of FRPs, each side of which is joined to the inner surface of the hollow member, and which are arranged at intervals along the member longitudinal direction of the hollow member so as to separate the inner space of the hollow member. And a plate-shaped reinforcing member, the minimum width of the hollow member in external dimensions is 30% or more of the maximum width of external dimensions of the hollow member in a cross section perpendicular to the member longitudinal direction. The reinforcing member has a plate surface of the reinforcing member in a direction perpendicular to the member longitudinal direction of the hollow member, and from the end of the hollow member in the member longitudinal direction, 0.74 times the minimum width. A structural member for a vehicle, wherein three or more sheets are arranged at an interval of ˜1.84 times and the reinforcing member has a plate thickness of 0.7 to 3.0 mm.

Description

(Cross-reference of related applications)
The present application claims priority based on Japanese Patent Application No. 2018-136982 filed in Japan on July 20, 2018, the contents of which are incorporated herein by reference.

The present invention relates to a vehicle structural member.

In recent years, from the viewpoint of protecting the global environment, improvement in fuel efficiency of automobiles has been demanded. On the other hand, there is a demand for maintaining or improving collision safety of vehicles. In order to satisfy these requirements, development of a high-strength and lightweight vehicle body structure is under way. With regard to the frame, which is a structural member for vehicles and forms the skeleton of the vehicle body, in order to reduce the weight of the vehicle body structure while maintaining the conventional collision performance, the strength and thinning of the steel plate forming the frame are being promoted. ing.

Further, in order to improve the collision safety of the vehicle, it is required to improve the energy absorption performance of the front portion and the rear portion of the vehicle, which is also called “crushable zone”. For example, there is a part called a front side member in the crushable zone of the front part. For example, at the time of a frontal collision of a vehicle, a load is mainly input to the front side member from the longitudinal direction (axial direction) of the member, but at that time, the front side member undergoes compressive bending deformation. Generally, in compressive bending deformation, only the bent portion is buckled and plastically deformed, but other portions are not plastically deformed. On the other hand, the axial crush deformation in which buckling is continuously generated and deforms in a bellows shape has a large plastic deformation region and has a higher energy absorption efficiency than bending deformation. However, it is difficult to stably generate the axial crushing deformation under the condition that the input direction of the load at the time of collision is not uniquely determined like a vehicle. Therefore, it is more preferable that a member such as a front side member of a vehicle absorbs energy while undergoing compressive bending deformation at the time of collision.

As a technique aiming at improving energy absorption performance at the time of a vehicle collision, Patent Document 1 discloses that a plurality of ribs are provided so that an inner space of a front portion of a hollow frame member is divided at regular intervals in a member longitudinal direction. Arranged techniques are disclosed. No rib is arranged at the rear of the hollow frame member.

Further, Patent Document 2 discloses a welded structure closed cross-section frame which is used for a vehicle body frame, a suspension frame, or the like of an automobile, and which is configured to prevent an opening or breakage at a welded portion at the time of a collision. In this technique, a plate-shaped metal reinforcing member is provided in the hollow member. Further, Patent Document 3 discloses a configuration in which a plurality of reinforcing members are provided inside a hollow member (strength member) having a closed cross-section structure, and discloses a technique of using a synthetic resin as the reinforcing member. Further, Patent Document 4 discloses a technique of attaching a reinforcing member to the inner surface of a hollow member in a vehicle structural member, and also discloses that the hollow member has a tensile strength of 980 MPa or more.

JP, 2004-182189, A JP, 2010-76762, A Japanese Patent Laid-Open No. 11-342862 JP, 2017-159896, A

In Patent Document 1, with respect to the pitch of the wavy buckling waves (pitch of the buckling mode) generated when a load is input, the sum of the length of one side of the rectangular cross section of the hollow frame member and the length of the other side is constant. If so, it is disclosed that the pitch of the buckling mode does not change even if the ratio of the length of one side to the length of the other side changes. Patent Document 1 discloses that the length of one side and the buckling mode pitch are in a proportional relationship in the case of a square cross section.

However, when the present inventor examined the disclosure content of Patent Document 1, the relationship between the side length and the buckling mode pitch disclosed in Patent Document 1 was established when a static load was applied. , It was found that it does not hold when a dynamic load that simulates an actual automobile collision is applied. Therefore, even if the rib is arranged inside the hollow frame member based on the disclosure of Patent Document 1, the energy absorption performance may not be sufficiently improved.

Further, in the above Patent Documents 2 to 4, although it is disclosed that the impact is efficiently absorbed at the time of inputting a load and that load bearing performance is improved and weight reduction is achieved, the member is stably axially crushed. It cannot be said that the detailed conditions for causing the deformation and improving the energy absorption performance are sufficiently disclosed. In particular, the detailed configuration such as the arrangement, spacing, the number of sheets, and the plate thickness of the reinforcing members is not sufficiently disclosed, and there is room for further improvement of the energy absorption performance of the vehicle structural member.

Specifically, for example, in vehicle structural members such as front side members, rear side members, crash boxes, and extensions, high energy absorption performance is required to be stably obtained, and for that purpose, stable and continuous axial crushing is required. It is preferable that deformation occurs.

The present invention has been made in view of the above problems, and in a vehicle structural member, while achieving weight reduction, it is possible to stably generate axial crush deformation during a vehicle collision, and to maintain or improve energy absorption performance. To aim.

To solve the above problems, according to the present invention, a hollow member made of metal, and each side is joined to an inner surface of the hollow member, and a member longitudinal direction of the hollow member so as to separate an inner space of the hollow member. A plurality of plate-shaped reinforcing members made of FRP, which are arranged at intervals along with, in a cross section perpendicular to the member longitudinal direction of the hollow member, the minimum width of the hollow member on the outer dimension is It is 30% or more of the maximum width in the outer dimension of the hollow member, and each reinforcing member is oriented such that the plate surface of the reinforcing member is perpendicular to the member longitudinal direction of the hollow member and in the member longitudinal direction of the hollow member. From the end of the above, three or more sheets are arranged at an interval of 0.74 to 1.84 times the minimum width, and the reinforcing member has a plate thickness of 0.7 to 3.0 mm. Provided.

The hollow member has a bending inducing portion in a part in the member longitudinal direction, and the spacing of the reinforcing members arranged in the bending inducing portion is the spacing of the reinforcing members arranged in a portion other than the bending inducing portion. May be narrower than

The hollow member has a bending inducing portion in a part in the member longitudinal direction, the plate thickness of the reinforcing member arranged in the bending inducing portion, of the reinforcing member arranged in a portion other than the bending inducing portion. It may be thicker than the plate thickness.

The hollow member has a bending inducing portion in a part in a member longitudinal direction, and the tensile strength of the reinforcing member arranged in the bending inducing portion is the reinforcing member arranged in a portion other than the bending inducing portion. It may be greater than the tensile strength of.

The FRP may be CFRP or GFRP.

The tensile strength of the hollow member may be 980 MPa or more.

The vehicle structural member may be any of a front side member, a rear side member, an extension, and a crash box.

According to the present invention, in a structural member for a vehicle, it is possible to stably generate axial crush deformation during a vehicle collision and maintain or improve energy absorption performance while achieving weight reduction.

It is a perspective view showing the state where the frame for vehicles and other members concerning one embodiment of the present invention were joined. It is a top view showing the state where the frame for vehicles and other members concerning the embodiment were joined. It is a side view showing the state where the frame for vehicles and the other member concerning the embodiment are joined. It is a perspective view showing a schematic structure of a frame for vehicles concerning the embodiment. It is a perspective view which shows the shape of the reinforcing member which concerns on the same embodiment. It is a figure which shows the cross section perpendicular|vertical to the member longitudinal direction of the hollow member of the vehicle frame which concerns on the same embodiment. FIG. 7 is a sectional view taken along the line aa in FIG. 6. FIG. 7 is a sectional view taken along line bb in FIG. 6. It is a figure which shows the example of arrangement|positioning of the reinforcement member which concerns on the same embodiment. It is a figure which shows the example of arrangement|positioning of the reinforcement member which concerns on the same embodiment. FIG. 6 is a cross-sectional view of a hollow member for explaining an example of a hole provided in the hollow member according to the same embodiment. It is a schematic diagram which shows the other example of the hole part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the hole part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the hole part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the hole part provided in the hollow member which concerns on the same embodiment. FIG. 6 is a cross-sectional view of a hollow member for explaining an example of a bead portion provided in the hollow member according to 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 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. FIG. 6 is a cross-sectional view of a hollow member for explaining an example of a convex portion provided in the hollow member according to the same embodiment. It is a schematic diagram which shows the other example of the convex part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the convex part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the convex part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the convex part provided in the hollow member which concerns on the same embodiment. It is a schematic diagram which shows the other example of the convex part provided in the hollow member which concerns on the same 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 same embodiment. It is a schematic diagram which shows an example of the thin part provided in the hollow member which concerns on the same embodiment. FIG. 6 is a cross-sectional view of a hollow member for explaining an example of a different strength portion provided in the hollow member according to the same embodiment. It is a schematic diagram which shows the other example of the different 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 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 same embodiment. It is a top view which shows the state in the middle of the deformation|transformation of the vehicle frame of a comparative example (structure 1). It is a top view showing the state after modification of the frame for vehicles of a comparative example (structure 1). It is a top view which shows the state in the middle of the deformation|transformation of the vehicle frame of a comparative example (structure 4). It is a top view which shows the state after the deformation|transformation of the vehicle frame of a comparative example (structure 4). It is a top view which shows the state in the middle of the deformation|transformation of the vehicle frame of the invention example (structure 7). It is a top view showing the state after modification of the frame for vehicles of the example of an invention (structure 7). It is a figure which compared the energy absorption performance of each analysis model in a collision simulation.

An embodiment of the present invention will be described below with reference to the drawings. In the present specification and the drawings, elements having substantially the same functional configuration are designated by the same reference numerals, and duplicate description will be omitted.

<1. Applications 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 of absorbing and absorbing a shock to the vehicle (shock absorbing function) by the structure itself being crushed at the time of a vehicle collision. That is, in order to ensure the safety of an occupant riding in the cabin at the time 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 forming the front structure and the rear structure are required to absorb a large amount of collision energy even when bending or crushing occurs during a collision. The frame used for the front structure and the rear structure is, for example, a front side member or a rear side member. 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 side 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 portion on the front side of the rear end portion.

By the way, in order to maintain both collision safety and weight reduction of a vehicle, the strength and thickness of the steel sheet forming the vehicle body structure are being advanced. As for the frames forming the front structure, the rear structure, and the cabin structure described above, replacement of thin-walled high-strength steel plates is in progress. Specifically, the plate thickness of the frame formed by the high-strength steel plate is set by 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 by the conventional steel plate. It is set thinner than the frame to be formed. This makes it possible to reduce the weight of the frame while maintaining the collision performance of the high-strength frame equal to that of the conventional frame.

<2. Structure of vehicle frame>
(Frame components)
FIG. 1 is a perspective view showing a state in which a vehicle frame 1 according to an embodiment of the present invention and other members are joined. FIG. 2 is a plan view of that state, and FIG. 3 is a side view of that state. The vehicle frame 1 in the example shown in FIGS. 1 to 3 is a front side member, and the front end of the front side member is joined to the bumper beam 40 via the crash box 30. Normally, two front side members are symmetrically arranged in front of the cabin portion, and only one of the two is shown in FIGS. 1 to 3. The vehicle frame 1 is an example of a vehicle structural member, and is hereinafter simply referred to as the frame 1. The frame 1 is preferably applied to members related to the front structure and the rear structure, but it is also possible to apply the vehicle frame 1 to members related to the cabin structure. The structural member for a vehicle is applicable not only to an automobile but also to other vehicles and self-propelled machines. Other vehicles and self-propelled machines include, for example, two-wheeled vehicles, large vehicles such as buses or towing vehicles, trailers, railway vehicles, construction machines, mining machines, agricultural machines, general machines, and ships.

As shown in FIGS. 4 to 6, the frame 1 of the present embodiment includes a hollow member 10 made of metal and a plurality of reinforcing members 20 arranged inside the hollow member 10.

The hollow member 10 of the present embodiment is an example of a long structural member, and has a rectangular cross section perpendicular to the member longitudinal direction (X direction in the present embodiment). The hollow member 10 of the present embodiment is a rectangular tubular member formed as an integrated body, but the hollow member 10 is configured by joining, for example, a flat plate-shaped closing plate and a member having a hat-shaped cross section. May be. That is, the hollow member 10 is not particularly limited in configuration as long as the cross section perpendicular to the member longitudinal direction X is a closed cross section. For example, although the hollow member 10 has a rectangular shape as an example of a polygonal shape in the present embodiment, the hollow member 10 may have a polygonal shape other than a rectangular shape. However, as will be described later, in the cross section of the hollow member 10 perpendicular to the member longitudinal direction X, the minimum width W _min in the external dimension is 30% or more of the maximum width W _{max in} the external dimension. Is composed of.

As shown in FIG. 6, the hollow member 10 of this embodiment has four flat surface portions 11a to 11d. In the following description, among these four flat surface portions 11a to 11d, the flat surface portion located on the upper side in FIG. 6 is the top surface portion 11a, the flat surface portion located on the right side is the side surface portion 11b, and the flat surface portion located on the lower side. The bottom surface portion 11c and the flat surface portion located on the left side are referred to as side surface portions 11d. Further, the connecting portion between the two flat surface portions 11a and 11b, which is a boundary portion between the top surface portion 11a and the side surface portion 11b, is a ridge line portion 11e, and the both flat surface portion 11b is a portion that is a boundary portion between the side surface portion 11b and the bottom surface portion 11c. , 11c is a ridge line portion 11f, and both flat surface portions 11c and 11d which are boundaries between the bottom surface portion 11c and the side surface portion 11d are ridge line portions 11g and a boundary portion between the side surface portion 11d and the top surface portion 11a. The connecting portion between the two flat surface portions 11d and 11a, which is the portion to be formed, is referred to as a ridge portion 11h.

The hollow member 10 is formed of a metal plate. The type of metal plate is not particularly limited, but it is preferably formed by a metal plate such as a steel plate. From the viewpoint of collision performance, the plate thickness of the hollow member 10 is preferably 6.0 mm or less in a frame structure that is often used in large vehicles such as buses, and is 3. 0 in a monocoque structure vehicle that is often used in ordinary size vehicles. It is preferably 2 mm or less. If necessary, the lower limit of the plate thickness may be 0.8 mm, 1.0 mm or 1.2 mm. Further, the tensile strength of the metal plate forming the hollow member 10 (hereinafter referred to as "tensile strength of the hollow member 10") is not particularly limited. However, the tensile strength of the hollow member 10 is preferably 590 MPa or more in order to supplement the overall strength of the frame 1 that can be reduced by weight reduction. Further, the tensile strength of the hollow member 10 is more preferably 980 MPa or more. If necessary, the upper limit of the tensile strength of the hollow member 10 may be 2000 MPa or 1500 MPa.

The reinforcing member 20 is a plate-shaped FRP member. Flange 21a-21d is formed in each linear part of the rectangular plate surface 20a. In the reinforcing member 20 of the present embodiment, the shape of the plate surface 20a is similar to the shape of the cross section of the hollow member 10 perpendicular to the member longitudinal direction X, and the plate surface 20a extends in the member longitudinal direction X of the hollow member 10. It is provided inside the hollow member 10 in a vertical direction. The flange 21a of the reinforcing member 20 is on the inner surface of the top surface portion 11a of the hollow member 10, the flange 21b is on the inner surface of the side surface portion 11b of the hollow member 10, the flange 21c is on the inner surface of the bottom surface portion 11c of the hollow member 10, and the flange 21d is hollow. It is joined to the inner surface of the side surface portion 11d of the member 10, respectively. Thereby, the reinforcing member 20 is fixed to the hollow member 10. The reinforcing member 20 fixed in this way functions as a so-called bulkhead that covers the inner space of the hollow member 10 in a cross section perpendicular to the member longitudinal direction X. The shape of the reinforcing member 20 is appropriately changed so that the reinforcing member 20 functions as a bulkhead depending on the shape of the hollow member 10, the method of joining the hollow member 10 and the like.

Note that, here, the case where the reinforcing member 20 is joined to the inner surface of the hollow member 10 via the flanges 21a to 21d formed on the respective straight portions (each side) of the rectangular plate surface 20a is illustrated and described. The joining method and its mode are not limited to this. For example, the plate surface 20a may be directly joined to the inner surface of the hollow member 10 without forming a flange on each side of the reinforcing member 20 having the rectangular plate surface 20a. Further, the joining range does not necessarily have to be the entire circumference of the reinforcing member 20, and for example, 50% or more of the length of each side of the reinforcing member 20 may be joined to the inner surface of the hollow member 10.

(Example of reinforcing member)
The FRP member used as the reinforcing member 20 means a fiber reinforced resin member made of a matrix resin and a reinforced fiber material contained in the matrix resin and compounded.

As the reinforcing fiber material, for example, carbon fiber or glass fiber can be used. Besides, as the reinforcing fiber material, boron fiber, silicon carbide fiber, aramid fiber or the like can be used. In the FRP used for the FRP member, examples of the reinforcing fiber base material that serves as the base material of the reinforcing fiber material include a non-woven 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 base materials can be appropriately selected depending on the orientation of the reinforcing fiber material.

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

The GFRP member is an FRP member using glass fiber as a reinforcing fiber material. Although it is inferior in mechanical properties to carbon fiber, electrolytic corrosion of the metal member can be suppressed.

As the matrix resin used for the FRP member, either a thermosetting resin or a thermoplastic resin can be used. Examples of the thermosetting resin include epoxy resin, unsaturated polyester resin, vinyl ester resin and the like. Examples of the thermoplastic resin include 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, polyether sulfone. , Polyphenylene ether and its modified products, polyarylate, polyether ketone, polyether ether ketone, polyether ketone ketone, 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 the matrix resin from the viewpoint of workability and productivity. Furthermore, by using a phenoxy resin as the matrix resin, the density of the reinforcing fiber material can be increased. Moreover, since the phenoxy resin has a molecular structure very similar to that of the thermosetting epoxy resin, it has the same heat resistance as the epoxy resin. Further, by adding a curing component, application to a high temperature environment becomes possible. When the hardening component is added, the addition amount thereof may be appropriately determined in consideration of the impregnation property into the reinforcing fiber material, the brittleness of the FRP member, the tact time, the processability, and the like.

(Adhesive resin layer)
When the reinforcing member 20 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 adhesive resin layer separates the FRP member and the metal member. It may be joined.

The type of the adhesive resin composition forming the adhesive resin layer is not particularly limited. For example, the adhesive resin composition may be either a thermosetting resin or a thermoplastic resin. The types of thermosetting resin and thermoplastic resin are not particularly limited. Examples of the thermoplastic resin include polyolefin and its acid-modified products, polystyrene, polymethylmethacrylate, AS resin, ABS resin, thermoplastic aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonate, polyimide, polyamide, polyamide. At least one selected from imide, polyether imide, polyether sulfone, polyphenylene ether and its modified products, polyphenylene sulfide, polyoxymethylene, polyarylate, polyether ketone, polyether ether ketone, and polyether ketone ketone. can do. Further, as the thermosetting resin, for example, one or more selected from an epoxy resin, a vinyl ester resin, a phenol resin, and a urethane resin can be used.

The adhesive resin composition can be appropriately selected according to the characteristics of the matrix resin forming the FRP member, the characteristics of the reinforcing member 20, 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.

In this way, by adhering the FRP member to the metal member using the above-mentioned adhesive resin layer, the adhesion between the FRP member and the metal member can be improved. Then, the deformation followability of the FRP member when a load is input to the 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.

The form of the adhesive resin composition used for forming the adhesive resin layer may be, for example, powder, liquid such as varnish, or solid such as film.

Moreover, you may mix|blend a crosslinking hardening resin and a crosslinking agent with an adhesive resin composition, and may form a crosslinkable adhesive resin composition. Since this improves the heat resistance of the adhesive resin composition, it can be applied in a high temperature environment. As the crosslinking curable resin, for example, a bifunctional or higher functional epoxy resin or a crystalline epoxy resin can be used. Further, as the cross-linking agent, amine, acid anhydride or the like can be used. Further, the rubber composition, various rubbers, inorganic fillers, solvents and other additives may be added to the adhesive resin composition as long as the adhesiveness and physical properties are not impaired.

The compounding of the FRP member into the metal member is realized by various methods. For example, it can be obtained by adhering an FRP forming prepreg which is an FRP member or a precursor thereof to a metal member with the above-mentioned 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 composited by performing thermocompression bonding.

The above-described FRP or FRP molding prepreg may be bonded to the metal member before, during, or after molding of the component. For example, FRP or prepreg for FRP molding may be bonded to the metal member after the metal material that is the material to be processed is molded into the metal member. Alternatively, FRP or prepreg for FRP molding may be bonded to the work material by thermocompression bonding, and then the work material 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 also possible to perform molding such as bending 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.

The method of joining the FRP member and the metal member is not limited to the above-described bonding with the adhesive resin layer. For example, the FRP member and the metal member may be mechanically joined. More specifically, fastening holes are formed in the respective positions of the FRP member and the metal member, and these are fastened through the holes by fastening means such as bolts and rivets, whereby the FRP member and the metal member are fastened. It may be joined to the member. Alternatively, the FRP member and the metal member may be joined by known joining means. Further, the FRP member and the metal member may be joined together by a plurality of joining means. For example, the bonding by the adhesive resin layer and the fastening by the fastening means may be used in combination.

(Metal member and surface treatment)
The metal member according to the present invention may be plated. This improves the corrosion resistance. 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 the galvanized steel sheet (steel material), hot-dip galvanized steel sheet, hot-dip galvanized steel sheet, Zn-Al-Mg-based alloy-plated steel sheet, aluminum-plated steel sheet, galvanized steel sheet, electric Zn-Ni-based alloy plated steel sheet, etc. Can be used.

The surface of the metal member may be coated with a film called chemical conversion treatment. This further improves the corrosion resistance. 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 above film may be a known resin film.

Further, the metal member may be a generally known coating. This further improves the corrosion resistance. A known resin can be used for coating. For example, as the coating, a resin containing an epoxy resin, a urethane resin, an acrylic resin, a polyester resin, or a fluorine resin as a main resin can be used. In addition, generally known pigments may be added to the coating as needed. Further, 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 compounding the FRP member, or may be applied to the metal member after compounding the FRP member. Alternatively, the FRP member may be composited after the metal member is coated in advance, and then the FRP member may be further coated. The paint used for coating may be solvent-based paint, water-based paint, powder paint, or the like. A generally known method can be applied as a method for applying the coating. For example, electrodeposition coating, spray coating, electrostatic coating, dip coating, or the like can be used as the coating method. Electrodeposition coating is suitable for coating the end surfaces and gaps of metal members, and therefore has excellent corrosion resistance after coating. Further, the adhesion of the coating film is improved by subjecting the surface of the metal member to a generally known chemical conversion treatment such as zinc phosphate treatment or zirconia treatment before coating.

<3. Example of arrangement of reinforcing members>
As shown in FIG. 4, the plurality of reinforcing members 20 are arranged at intervals over the entire region in the member longitudinal direction X from the end of the hollow member 10 in the member longitudinal direction X. More specifically, as shown in FIGS. 7 and 8, each reinforcing member 20 in this embodiment has a space P from the front end 10a to the rear end 10b of the hollow member 10 so as to separate the inner space of the hollow member 10. It has been placed.

Here, in the present specification, the minimum width and the maximum width in the outer dimension of the hollow member 10 in a cross section perpendicular to the member longitudinal direction X of the hollow member 10 are used as a reference. In the case of this embodiment, the outer dimension on the short side of the substantially rectangular cross section shown in FIG. 6 is the minimum width W _min , and the outer dimension width on the long side of the substantially rectangular cross section is the maximum width W _max . In the cross section of the hollow member 10 of the present embodiment, a pair of opposing short sides and a pair of opposing long sides are configured to be equal to each other. Here, in the cross section perpendicular to the member longitudinal direction X of the hollow member 10, the minimum width W _min in the external dimension is configured to be 30% or more of the maximum width W _{max in} the external dimension. .. Regarding the ratio of the minimum width W _min in the external dimensions and the maximum width W _{max in} the external dimensions (that is, the flatness ratio of the cross section), if the minimum width W _min is not 30% or more of the maximum width W _max , it is hollow. The member 10 may not be stably deformed by axial compression, and is not effective as a shock absorbing member. If necessary, the minimum width W _min may be set to 35% or 40% or more of the maximum width W _max . From the definition, the minimum width W _min never becomes larger than the maximum width W _max .

The interval P between the reinforcing members 20 arranged inside the hollow member 10 is 0.74 to 1.84 times the minimum width W _{min in} the outer dimension of the hollow member 10. That is, in the present embodiment, each reinforcing member 20 is arranged along the member longitudinal direction X of the hollow member 10 at the interval P of 0.74 to 1.84 times the minimum width W _{min in} the outer dimension of the hollow member 10. Are arranged. Further, in the case of the hollow member 10 having a shape that changes in the member longitudinal direction X, the minimum width W _min is defined with reference to the sectional shape of the hollow member 10 at the position where the area of the cross section perpendicular to the member longitudinal direction X is the smallest. ..

As shown in Examples described later, when the distance P between the reinforcing members 20 is 0.74 to 1.84 times the minimum width W _{min in} the outer dimension of the hollow member 10, the member longitudinal direction of the hollow member 10 When a high load is input from X, the hollow member 10 stably undergoes axial crush deformation. The reason why such deformation occurs is as follows.

Since the reinforcing effect is great in the place where the reinforcing member 20 is arranged, when a high load is input from the front end 10a of the hollow member 10, first, the place where the first reinforcing member 20 closest to the front end 10a is arranged. The hollow member 10 is deformed in a portion in front of. After that, the deformation of the hollow member 10 progresses toward the rear end 10b, and the deformation of the portion of the hollow member 10 where the first reinforcing member 20 is arranged is started. Since FRP has low ductility, the first reinforcing member 20 breaks at this stage. That is, the reinforcing effect is lost at the location where the first reinforcing member 20 is arranged, and the hollow member 10 at that location is easily deformed.

On the other hand, at the location where the second and subsequent reinforcing members 20 are arranged, since the reinforcing member 20 is not broken, the reinforcing effect is maintained without being lost. That is, the hollow member 10 is in a state in which it is difficult to deform at the location where the second and subsequent reinforcing members 20 are arranged. Therefore, until the deformation of the hollow member 10 at the location where the broken first reinforcing member 20 is arranged is sufficiently advanced, the deformation amount of the hollow member 10 at the location where the second and subsequent reinforcing members 20 are arranged is It is getting smaller. Then, after the deformation of the front region of the portion where the second reinforcing member 20 is arranged sufficiently progresses, the deformation of the hollow member 10 where the second reinforcing member 20 is arranged is started. Since the FRP has low ductility as described above, the second reinforcing member 20 breaks at this stage. As a result, the reinforcing effect is lost at the location where the second reinforcing member 20 is arranged, and the hollow member 10 at that location is easily deformed.

The above-described deformation also occurs repeatedly at the places where the third and the subsequent reinforcing members 20 are arranged. That is, in the frame 1 of the present embodiment, the hollow member 10 is deformed while the reinforcing members 20 arranged along the member longitudinal direction X of the hollow member 10 are fractured in order from the end portion on the load input side. proceed. Accordingly, when a load is input from the member longitudinal direction X of the hollow member 10, axial crush deformation can be stably generated, and high energy absorption performance can be stably obtained.

On the other hand, when the interval P between the reinforcing members 20 does not satisfy 0.74 to 1.84 times the minimum width W _{min in} the outer dimension of the hollow member 10, stable hollow deformation occurs in the hollow member 10. There is a fear of not. When the interval P is shorter than 0.74 times the minimum width W _{min in} the outer dimension of the hollow member 10, the rigidity becomes too high, and there is a risk that buckling will not occur between the reinforcing members 20. When the interval P is more than 1.84 times the minimum width W _{min in} the outer dimension of the hollow member 10, the space between the reinforcing members 20 is too long, and therefore lateral bending deformation occurs at one location, which does not result in axial crush deformation. There is a fear. If necessary, the lower limit of the interval P between the reinforcing members 20 may be 0.80 times, 0.85 times, or 0.90 times the minimum width W _{min in} the outer dimension of the hollow member 10. If necessary, the upper limit of the interval P between the reinforcing members 20 may be set to 1.60 times, 1.50 times, or 1.40 times the minimum width W _{min in} the outer dimension of the hollow member 10.

Further, from the viewpoint of enhancing the weight efficiency of energy absorption performance, the tensile strength of the FRP member forming the reinforcing member 20 (hereinafter referred to as “tensile strength of the reinforcing member 20”) is preferably 100 MPa or more. If necessary, the upper limit of the tensile strength may be 2500 MPa or 2000 MPa. Further, as shown in Examples described later, the plate thickness of the reinforcing member 20 is preferably 0.7 to 3.0 mm. The lower limit of the plate thickness of the reinforcing member 20 may be 0.8 mm, 0.9 or 1.0 mm. The upper limit of the plate thickness may be 2.9 mm, 2.8 mm, 2.4 mm or 2.0 mm.
The ductility of a metal plate such as a steel plate is generally good. For this reason, when the reinforcing member 20 is a metal plate, the reinforcing member 20 does not break as described above, and thus high energy absorption performance cannot be stably obtained. Therefore, the reinforcing member 20 needs to be an FRP member.

Although the arrangement of the reinforcing member 20 according to the present embodiment has been described above, the arrangement of the reinforcing member 20 is not limited to the example shown in FIG. For example, as shown in FIG. 9, each reinforcing member 20 may not be arranged over the entire region in the member longitudinal direction X. In the example shown in FIG. 9, the reinforcing member 20 has an end on the load input side (the front end 10a in the present embodiment) of the front part and the rear part with the center position of the hollow member 10 in the member longitudinal direction X as a boundary. It is located only in the front. Even in this case, in the region where the reinforcing member 20 is arranged, the axial crush deformation can be stably generated when the load is input. From the viewpoint that the axial crush deformation is stably generated at the time of inputting a load, three or more sheets are provided in the front part of the hollow member 10 in the member longitudinal direction X with an interval P from the end part (front end 10a) on the load input side. It is sufficient that the reinforcing member 20 is arranged. Further, in the member longitudinal direction X of the hollow member 10, it is preferable that the reinforcing member 20 is arranged within a range of 15%, 20%, or 30% in length from the end portion (front end 10a) on the load input side. More preferably, the number of reinforcing members 20 is 4 or more, 5 or more, or 6 or more.

In addition, in the above-described embodiment, the interval P between the reinforcing members 20 is constant along the member longitudinal direction X of the hollow member 10, but the interval P is the minimum width W _{min in} the outer dimension of the hollow member 10. If it is within the range of 0.74 to 1.84 times, the interval P does not have to be constant along the member longitudinal direction X as shown in FIG. In the example shown in FIG. 10, the interval between the reinforcing members 20 arranged in the front part of the hollow member 10 in the member longitudinal direction X and the interval between the reinforcing members 20 arranged in the rear part are different.

Further, the shape of the hollow member 10 is appropriately changed depending on the application of the structural member for a vehicle, but the portion that is likely to be bent and deformed depending on the shape of the hollow member 10 and the other portion are reinforced. By changing the interval P of the members 20, the plate thickness, the strength, etc., it is possible to reinforce the portion where bending deformation is likely to occur. As a result, it is possible to generate axial crush deformation with high energy absorption efficiency at a site where bending deformation has conventionally occurred and energy absorption efficiency was not necessarily high. In the present specification, a portion where such bending deformation is likely to occur is referred to as a "bending inducing portion".

It is preferable that the interval P between the reinforcing members 20 arranged in the bending inducing portion is narrower than the interval P between the reinforcing members 20 in the portions other than the bending inducing portion. As a result, the reinforcing effect in the bending inducing portion is enhanced, and the axial crush deformation can be generated more stably. For the same reason, it is preferable that the plate thickness of the reinforcing member 20 arranged in the bend inducing section is thicker than the plate thickness of the reinforcing member 20 arranged in the portion other than the bend inducing section. Further, for the same reason, it is preferable that the tensile strength of the reinforcing member 20 arranged in the bending inducing portion is higher than the tensile strength of the reinforcing member 20 arranged in the portion other than the bending inducing portion. Further, the above-described setting methods of the interval P, the plate thickness, the tensile strength, and the like in the bending inducing portion may be appropriately combined.

<4. Example of bending induction part>
Next, an example of the bending inducing portion provided in the hollow member 10 will be described. For example, a hole, a recess, a protrusion, a plate thickness changing portion, a different strength portion, etc. provided in the hollow member 10 realize the function as the bending inducing portion. The portion where any of the hole portion, 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 member longitudinal direction X of the hollow member 10. In the portion of the hollow member 10 where the section modulus changes in the member longitudinal direction X, the bending stress generated in the hollow member 10 changes due to the same bending moment, so that bending of the hollow member 10 is induced in that portion. More specifically, in the portion having a relatively small section modulus in the hollow member 10 in the member longitudinal direction X, the bending stress in that portion becomes relatively large, so that bending occurs in that portion. In addition, regarding a portion of the hollow member 10 having a relatively large section modulus in the member longitudinal direction X, the section modulus of a portion including a region before and after the hollow member 10 in the member longitudinal direction X is relatively small. .. Therefore, bending occurs at the boundary 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 member longitudinal direction X of the hollow member 10. In the portion of the hollow member 10 where the yield strength changes in the member longitudinal direction X, plastic deformation of the hollow member 10 in that portion is induced. For example, regarding the portion of the hollow member 10 in which the yield strength is relatively small in the member longitudinal direction X, the plastic deformation in that portion occurs first in the hollow member 10, so that bending occurs in that portion. Further, regarding the portion of the hollow member 10 having a relatively high yield strength in the member longitudinal direction X, the yield strength of the portion including the regions before and after the hollow member 10 in the member longitudinal direction X is relatively low. .. Therefore, bending occurs at the boundary between the region and the portion where the yield strength is relatively large.

Further, even if the hollow member 10 does not have a portion including a hole portion, a concave portion, a convex portion, a plate thickness changing portion, a different strength portion, etc. that realizes the function as the bending inducing portion described above, the load applied to the hollow member 10 When the input direction can be specified to some extent, there is a region in the hollow member where the bending moment is maximum due to the influence of the constraint of the peripheral member joined to the hollow member 10, and bending occurs in the region. Therefore, when the bending moment generated in the hollow member 10 can be specified, the region where the bending moment is maximum also has a function as a bending inducing portion.

Hereinafter, specific examples of the bending inducing portion provided in the hollow member 10 will be described.

(Hole)
FIG. 11 is a cross-sectional view of the hollow member 10A for explaining an example of a hole provided in the hollow member 10A according to this embodiment. As shown in FIG. 11, a hole 50 is provided in the side surface portion 11b. 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 hollow member 10A in the portion before and after the portion where the hole 50 is provided. Therefore, when the collision load F shown in FIG. 11 is input to the hollow member 10A, the hollow member 10A bends at the portion where the hole 50 is provided so that the hole 50 is on the inside of the bend. That is, in the member longitudinal direction X of the hollow member 10A, the portion of the hollow member 10A where the hole 50 is provided becomes the bending inducing portion provided in the hollow member 10A.

Further, the shape and arrangement of the hole are not limited to the above-mentioned example. 12 to 15 are schematic diagrams showing other examples of the hole provided in the hollow member 10A according to the present embodiment. As shown in FIG. 12, a circular hole 50a may be provided in the side surface portion 11b. Further, as shown in FIG. 13, a plurality of holes 50b may be provided in the side surface portion 11b. In this case, for example, the plurality of holes 50b may be provided side by side in the direction crossing the member longitudinal direction X of the hollow member 10A. In this case, when the collision load is input, the hollow member 10A easily bends and deforms toward the side surface portion 11b with the hole portion 50b as a bending starting point.

Further, as shown in FIG. 14, a hole 50c extending in a direction transverse to the member longitudinal direction X of the hollow member 10A may be provided in the side surface part 11b. In this case, when the collision load is input, the hollow member 10A is bent and deformed toward the side surface part 11b with the hole 50c as a starting point of bending. The shape of the hole 50c is not limited to the rounded rectangle shown in FIG. 14, and may be any shape. In addition, the direction crossing the member longitudinal direction X of the hollow member 10A described above is not limited to the direction orthogonal to the member longitudinal direction X of the hollow member 10A as shown in FIGS.
Further, the portion where the hole 50 is provided is not limited to the side surface portion 11b. For example, the hole 50 may be provided in the top surface portion 11a, the bottom surface portion 11c, or the side surface portion 11d.

Further, as shown in FIG. 15, the hole 50d may be provided in the ridge line portion 11e. As a result, the section modulus of the portion of the hollow member 10A in which the hole 50d is provided in the member longitudinal direction X is significantly reduced, so that the portion in which the hole 50d is provided is likely to be bent and deformed as a starting point of bending.

(Recess)
FIG. 16 is a cross-sectional view of the hollow member 10B for explaining an example of a bead portion provided in the hollow member according to this embodiment. The bead portion 51 is an example of the concave portion in the present embodiment. As shown in FIG. 16, a bead portion 51 is provided on the side surface portion 11b. 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 hollow member 10B in the portion before and after the portion where the bead portion 51 is provided. Therefore, when the collision load F shown in FIG. 16 is input to the hollow member 10B, the hollow member 10B bends at the portion where the bead portion 51 is provided so that the bead portion 51 is on the inside of the bend. That is, in the member longitudinal direction X of the hollow member 10B, the portion of the hollow member 10B where the bead portion 51 is provided becomes the bending inducing portion provided in the hollow member 10B.

Note that the shape and arrangement of the recesses are not limited to the examples described above. 17 to 20 are schematic diagrams showing other examples of the recesses provided in the hollow member 10B according to the present embodiment. The recessed portion here means a recessed portion such as an emboss or bead provided in the side surface portion 11b of the hollow member 10B. As shown in FIG. 17, a circular recess 51a may be provided in the side surface portion 11b.

Further, as shown in FIG. 18, a plurality of recesses 51b may be provided in the side surface portion 11b. In this case, for example, the plurality of recesses 51b may be provided side by side in the direction crossing the member longitudinal direction X of the hollow member 10B. In this case, when the collision load is input, the hollow members 10B are likely to be bent and deformed toward the side surface portion 11b with the plurality of recesses 51b serving as starting points of bending.

Further, as shown in FIG. 19, a bead portion 51c extending in a direction transverse to the member longitudinal direction X of the hollow member 10B may be provided on the side surface portion 11b. In this case, when the collision load is input, the hollow portion 10B is bent and deformed toward the side surface portion 11b with the bead portion 51c as a bending start point. The shape of the bead portion 51c is not limited to the rounded rectangle shown in FIG. 19, and may be any shape.
Note that the direction crossing the member longitudinal direction X of the hollow member 10B described above is not limited to the direction orthogonal to the member longitudinal direction X of the hollow member 10B as shown in FIG.
Further, the portion where the concave portion 51 is provided is not limited to the side surface portion 11b. For example, the recess 51 may be provided in the top surface portion 11a, the bottom surface portion 11c, or the side surface portion 11d.

Further, as shown in FIG. 20, the recess 51d may be provided in the ridge line portion 11e. As a result, the section modulus of the portion of the hollow member 10B where the recess 51d is provided in the longitudinal direction X of the member remarkably changes, so that the portion where the recess 51d is provided easily bends and deforms as the starting point of bending.

FIG. 21 is a schematic view showing another example of the recess provided in the hollow member 10B according to the present embodiment. As shown in FIG. 21, the recesses 51e and 51f extending in the member longitudinal direction X of the hollow member 10B may be provided side by side along the member longitudinal direction X of the hollow member 10B. In this case, the hollow member 10B is bent at a portion 510 between the recess 51e and the recess 51f in the member longitudinal direction X. That is, in the hollow member 10B, since the section coefficient is different between the portion provided with the recessed portions 51e and 51f and the portion 510 between the recessed portions 51e and 51f, when the collision load is input, the portion 510 is bent. Bending deformation occurs as the starting point of. In addition, a concave portion, a convex portion described later, a thin portion, a different strength portion, or the like may be formed in the portion 510. Note that the recesses 51e and the recesses 51f do not necessarily have to be arranged in series as shown in FIG. The recesses 51e and 51f do not necessarily have to extend in the member longitudinal direction X of the hollow member 10B.

(Projection)
FIG. 22 is a cross-sectional view of the hollow member 10C for explaining an example of the convex portion provided on the hollow member 10C according to the present embodiment. As shown in FIG. 22, a convex portion 52 is provided on the side surface portion 11b. The section modulus of the hollow member 10C in the portion where the protrusion 52 is provided is higher than the section modulus of the hollow member 10C in the portion before and after the portion where the protrusion 52 is provided. Therefore, when the collision load F shown in FIG. 22 is input to the hollow member 10C, in the region 6a or the region 6b before and after the convex portion 52 in the member longitudinal direction X of the hollow member 10C, the portion having the lowest section modulus is obtained. , So that the convex portion 52 is bent inward. The regions 6a and 6b are regions where the cross-sectional coefficient of the hollow member 10C changes in the Y direction. That is, in the member longitudinal direction X of the hollow member 10C, the portion of the hollow member 10C that includes the convex portion 52 and the regions 6a and 6b before and after the convex portion 52 becomes the bending inducing portion provided in the hollow member 10C.

Note that, in the example shown in FIG. 22, the convex portion 52 is provided on the side surface portion 11b, but the convex portion 52 may be provided on, for example, the top surface portion 11a, the bottom surface portion 11c, or the side surface portion 11d. More specifically, when the convex portion 52 is provided on the top surface portion 11a, the bottom surface portion 11c, or the side surface portion 11d on the same cross section in a part in the member longitudinal direction X of the hollow member 10C, the hollow member 10C Since the section modulus in the member longitudinal direction X changes in the portion where the convex portion 52 is provided, bending of the hollow member 10C may occur in the portion where the convex portion 52 is provided. Therefore, also in this case, the convex portion 52 becomes the bending inducing portion.

Further, the shape and arrangement of the convex portion are not limited to the above-mentioned example. 23 to 26 are schematic diagrams showing other examples of the convex portions provided in the hollow member 10C according to the present embodiment. The convex portion here is realized, for example, by processing the hollow member 10C. That is, such a convex portion may be provided by deforming a part of the steel plate forming the hollow member 10C. As shown in FIG. 23, a circular convex portion 52a may be provided on the side surface portion 11b.

Further, as shown in FIG. 24, a plurality of convex portions 52b may be provided on the side surface portion 11b. In this case, for example, the plurality of convex portions 52b may be provided side by side in the direction crossing the member longitudinal direction X of the hollow member 10C. In this case, when the collision load is input, the hollow member 10C is easily bent and deformed toward the side surface portion 11b with one of the regions in front of and behind the plurality of convex portions 52b in the member longitudinal direction X of the hollow member 10C as the bending start point. Become.

Further, as shown in FIG. 25, a convex portion 52c extending in a direction crossing the member longitudinal direction X of the hollow member 10C may be provided on the side surface portion 11b. In this case, when the collision load is input, the hollow member 10C is bent and deformed toward the side surface portion 11b with one of the regions before and after the convex portion 52c in the member longitudinal direction X of the hollow member 10C as the starting point of bending. The shape of the convex portion 52c is not limited to the rounded rectangle shown in FIG. 25, and may be any shape. Note that the direction crossing the member longitudinal direction X of the hollow member 10C described above is not limited to the direction orthogonal to the member longitudinal direction X of the hollow member 10C as shown in FIG. Further, the portion where the convex portion 52 is provided is not limited to the side surface portion 11b. For example, the convex portion 52 may be provided on the top surface portion 11a, the bottom surface portion 11c, or the side surface portion 11d.

Further, as shown in FIG. 26, the convex portion 52d may be provided on the ridge line portion 11e. As a result, the section modulus of the portion of the hollow member 10C where the convex portion 52d is provided in the member longitudinal direction X significantly changes, and therefore the portion where the convex portion 52d is provided easily bends and deforms as the starting point of bending.

FIG. 27 is a schematic diagram showing another example of the convex portion provided in the hollow member 10C according to the present embodiment. As shown in FIG. 27, the convex portions 52e and 52f extending in the member longitudinal direction X of the hollow member 10C may be provided side by side along the member longitudinal direction X of the hollow member 10C. In this case, the hollow member 10C is bent at a portion 520 between the convex portion 52e and the convex portion 52f in the member longitudinal direction X. That is, in the hollow member 10C, the section in which the projections 52e and 52f are provided and the section 520 between the projections 52e and the projections 52f have different cross-section coefficients, and therefore when the collision load is input, the sections concerned are different. Bending deformation occurs with 520 as the starting point of bending. Further, in the portion 520, the above-mentioned concave portion, convex portion, or thin portion or different strength portion described later may be formed. Note that the convex portions 52e and the convex portions 52f do not necessarily have to be arranged in series as shown in FIG. Further, the convex portion 52e and the convex portion 52f do not necessarily have to extend in the member longitudinal direction X of the hollow member 10C.

(Thickness change part, thin part)
Further, a plate thickness changing portion may be provided on the side surface portion 11b as a configuration that realizes the bending inducing portion. FIG. 28 is a schematic diagram showing an example of the plate thickness changing portion provided in the hollow member 10D according to the present embodiment. The plate thickness changing portion here means a portion where the plate thickness changes in the member longitudinal direction X of the hollow member 10D. As shown in FIG. 28, 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 member longitudinal direction X 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 relationship between the plate thicknesses is not particularly limited.

In this case, as shown in FIG. 28, the boundary 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 of the hollow member 10D in the member longitudinal direction X changes. That is, the plate thickness changing portion 113 corresponds to the bending inducing portion. Therefore, when the collision load is input to the hollow member 10D, the hollow member 10D bends at the plate thickness changing portion 113.

Further, the bending inducing portion may be realized by a thin portion, for example. FIG. 29 is a schematic diagram showing an example of a thin portion provided in the hollow member 10D according to this embodiment. As shown in FIG. 29, the side surface portion 11b is provided with a thin portion 114 that is relatively thinner than other portions in the member longitudinal direction X of the hollow member 10D. The cross-sectional modulus of the hollow member 10D in the portion including the thin portion 114 is lower than the cross-sectional modulus of the hollow member 10D in the portions before and after the portion where the thin portion 114 is provided. That is, the portion of the hollow member 10D where the thin portion 114 is provided corresponds to the bending inducing portion. Therefore, when the collision load is input to the hollow member 10D, the hollow member 10D bends at the portion where the thin portion 114 is provided so that the thin portion 114 is on the inside of the bend.

The hollow member 10D having such a plate thickness changing portion may be formed of, for example, a plate to be processed including cutting, pressing, and a tailored blank. The plate to be processed may be a tailor welded blank (TWB) having a welding line. Further, the plate to be processed may be a tailor rolled blank (TRB) which is provided by changing the plate thickness by a rolling roll. In TWB, the thickness difference at the thickness change portion can be 0.2 mm or more. Further, in the TRB, the plate thickness change amount in the plate thickness change portion per member longitudinal direction can be set to 0.1 mm/100 mm or more.

(Different strength part/strength change part)
FIG. 30 is a cross-sectional view of the hollow member 10E for explaining an example of the different strength portion provided in the hollow member 10E according to this embodiment. As shown in FIG. 30, a different strength portion 53 is provided on the side surface portion 11b. 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 provided with the different strength portion 53 is different from the yield strength of the hollow member 10E in the portions before and after the portion provided with the different strength portion 53. Therefore, when the collision load F shown in FIG. 30 is input to the hollow member 10E, the different strength portion 53 or the vicinity of the different strength portion 53 bends so that the different strength portion 53 is on the inside of the bend. That is, in the member longitudinal direction X of the hollow member 10E, the portion of the hollow member 10E including the different strength portion 53 becomes the bending inducing portion provided in the hollow member 10E. This bending is bending caused by plastic deformation of the different strength portion 53 or a region near the different strength portion 53.

In the example shown in FIG. 30, the different strength portion 53 is provided on the side surface portion 11b, but the different strength portion 53 may be provided on, for example, the top surface portion 11a, the bottom surface portion 11c, or the side surface portion 11d. .. More specifically, when the different-strength portion 53 is provided in the top surface portion 11a, the bottom surface portion 11c, or the side surface portion 11d on the same cross section in a part of the hollow member 10 in the member longitudinal direction X, on the cross section. In, the side surface portion 11b has the lowest strength. Then, the bending of the hollow member 10E with the side surface portion 11b on the inner side of the bending may occur in the different strength portion 53. Therefore, also in this case, the different strength portion 53 becomes the bending inducing portion.

Further, the disposition of the different strength portions is not limited to the above example. 31 and 32 are schematic views showing another example of the different strength portion provided in the hollow member 10E according to the present embodiment. The different-strength portion here is realized by welding, heat treatment, or the like to the plate to be processed forming the hollow member 10E.

As shown in FIG. 31, the different-strength portion 120 is provided along the circumferential direction of the cross section of the hollow member 10E with respect to the member longitudinal direction X. Also in this case, the portion of the hollow member 10E where the different strength portion 120 is provided corresponds to the bending inducing portion. Therefore, when the collision load is input to the hollow member 10E, the hollow member 10E bends at the portion where the different strength portion 120 is provided so that the different strength portion 120 is on the inside of the bend.

Note that, for example, as shown in FIG. 32, the different strength portion may be partially provided on at least one of the wall portions forming the cross section of the hollow member 10E, such as the side surface portion 11b. Even in such a case, when the collision load is input to the hollow member 10E, the hollow member 10E bends in the portion where the different strength portion 121 is provided so that the different strength portion 121 is on the inside of the bend.

Further, the bending inducing section may be realized by, for example, the strength changing section. FIG. 33 is a schematic diagram showing an example of the strength changing portion provided in the hollow member 10E according to the present embodiment. As shown in FIG. 33, 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 member longitudinal direction X of the hollow member 10E. The yield strength of the steel sheet differs between the first strength portion 122 and the second strength portion 123. There is no particular limitation on the magnitude relationship of the yield strength.

In this case, as shown in FIG. 33, 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 of the hollow member 10E in the member longitudinal direction X changes. That is, the strength changing portion 124 corresponds to the bending inducing portion. Therefore, when the collision load is input to the hollow member 10E, the hollow member 10E bends at the strength changing portion 124.

(combination)
A plurality of examples of the bending inducing portion described above may be combined. For example, the bending inducing portion may be realized by a combination of at least two or more of the above-mentioned concave portion, convex portion, hole portion, plate thickness changing portion, thin portion, different strength portion and strength changing portion.

(Example of applicable parts)
The hollow member of the present embodiment can be applied to, for example, a vehicle structural member that requires a shock absorbing function, such as a front side member, a rear side member, an extension, or a crash box.

Although one embodiment of the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to such an 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.

A collision simulation was performed to evaluate the energy absorption performance of the frame according to the present invention. The analysis model is composed of a bumper beam and a frame as shown in FIGS. 1 to 3, the hollow member has a rectangular cross section, and the external dimensions are a width of 76 mm and a height of 200 mm. In addition, a plurality of analysis models are created under the conditions shown in Table 1 below. The weight reduction rate in Table 1 is the weight of each structure normalized by the weight of the structure 1.

The structure 1 and the structure 2 in the above Table 1 are structures in which the reinforcing member 20 is not provided, and the structure 2 is intended to have a thinner plate and a higher tensile strength than the structure 1. Structures 3 to 10 are structures in which a plurality of reinforcing members 20 as shown in FIG. 4 are arranged along the member longitudinal direction X of the hollow member 10, the material of the reinforcing member 20 is CFRP, and the plate thickness thereof is Is 0.8 mm. In the structure 3, the intervals between the adjacent reinforcing members 20 are random, and the intervals between the reinforcing members 20 are different from each other. In Structure 4 to Structure 8, the reinforcing members 20 are arranged in the entire region of the hollow member 10 in the member longitudinal direction X, and the intervals between the reinforcing members 20 are constant. In the structure 9, as shown in FIG. 9, the reinforcing member 20 is arranged only in the front part of the hollow member 10 in the member longitudinal direction X, and the intervals between the reinforcing members 20 are constant. In the structure 10, as shown in FIG. 10, the reinforcing members 20 are arranged in the entire region in the member longitudinal direction X of the hollow member 10, but the space between the reinforcing members 20 arranged in the front part of the hollow member 10 and the hollow member The intervals of the reinforcing members 20 arranged in the rear part of 10 are different.

Further, the structure 11 uses a steel plate as a material of the reinforcing member 20. The structure 12 is a structure in which the plate thickness of the reinforcing member 20 is changed to 2.8 mm. The structure 13 is a structure in which the plate thickness of the reinforcing member 20 is changed to 0.6 mm. The structure 14 is a structure in which the plate thickness of the reinforcing member 20 is changed to 3.2 mm. The structure 15 uses GFRP as the material of the reinforcing member 20. In the structure 16, the reinforcing member 20 is arranged only in the front part of the hollow member 10 in the member longitudinal direction X, and the number of the reinforcing members 20 is two.

The mechanical properties of CFRP used as the reinforcing member 20 in the structures 3 to 10, 12 to 14 and 16 are as follows.
Vf (volume ratio of fiber content): 50%
Young's modulus: 102 GPa
Breaking strength: 1500 MPa
Elongation at break: 1.5%

The mechanical properties of the steel plate used as the reinforcing member 20 in the structure 11 are as follows.
Tensile strength: 440MPa
Elongation at break: 28%
The mechanical characteristics of GFRP used as the reinforcing member 20 in the structure 15 are as follows.
Vf (volume ratio of fiber content): 50%
Young's modulus: 13 GPa
Breaking strength: 200 MPa
Elongation at break: 3.0%

This simulation simulated a frontal collision test of an automobile, and was carried out by causing a rigid wall having a mass of 200 kg to collide with the bumper beam 40 shown in FIGS. 1 to 3 at 12 m/s. The rear end 10b of the hollow member 10 in each analysis model is constrained. The simulation results will be described below.

In addition, in Table 1, the deformation mode of each analysis model is shown as a simulation result. “Horizontal bending” in the deformation modes shown in Table 1 is a deformation mode in which the horizontal bending deformation occurs from the initial deformation of the hollow member 10. “Unstable axial crush” in the deformation modes shown in Table 1 means that the crush deformation of the hollow member 10 occurs irregularly in the member longitudinal direction X, and the crush deformation occurs from the front end 10a of the hollow member 10. The deformation mode is not continuous to the rear end 10b. “Stable axial crush” in the deformation modes shown in Table 1 means that the crush deformation of the hollow member 10 gradually progresses along the member longitudinal direction X, and the crush deformation occurs continuously from the front end 10a to the rear end 10b. Mode.

FIG. 34 is a plan view showing a state in which the analysis model of the structure 1 in the collision simulation is in the middle of deformation, and FIG. 35 is a plan view showing a state after deformation of the analysis model of the structure 1 in the collision simulation. As shown in FIGS. 34 and 35, in the structure 1 in which the reinforcing member is not provided, when the load is input, the hollow member is laterally bent. Such deformation of the hollow member also occurred in the structures 2, 3, 11, and 16.

FIG. 36 is a plan view showing a state where the analysis model of the structure 4 in the collision simulation is in the middle of deformation, and FIG. 37 is a plan view showing a state after the deformation of the analysis model of the structure 4 in the collision simulation. As shown in FIG. 36, in the initial stage of deformation, the hollow member was crushed not only near the front end but also near the rear end, and the deformation mode was unstable axial crushing. Further, as shown in FIG. 37, when the deformation of the hollow member further progressed, lateral bending occurred in the central portion of the hollow member. Such deformation of the hollow member also occurred in the structures 5, 13, and 14.

On the other hand, FIG. 38 is a plan view showing a state during the deformation of the analysis model of the structure 7 in the collision simulation, and FIG. 39 is a plan view showing a state after the deformation of the analysis model of the structure 7 in the collision simulation. As shown in FIGS. 38 and 39, in the structure 7, the crushing deformation is stably generated during the deformation process of the hollow member. When the deformation mode of the hollow member is horizontal bending deformation, since the plastic strain generated in the portion other than the horizontal bending portion of the hollow member is small, the portion other than the horizontal bending portion does not substantially contribute to the improvement of energy absorption performance, but the structure When the deformation mode is stable axial crushing as in No. 7, there are many portions where plastic strain occurs, and it is possible to improve energy absorption performance. Such deformation of the hollow member also occurred in the structures 6, 8 to 10, 12 and 15.

Next, the energy absorption amount at the time of 750 mm stroke of the rigid wall was calculated from the load-stroke diagram when the rigid wall collided, and the energy absorption performance of each analytical model was compared. The result is shown in FIG. The vertical axis of the graph in FIG. 40 represents the ratio of the energy absorption amount of each structure and the energy absorption amount of structure 1.

As shown in FIG. 40, in the structures 6 to 10 and the structures 12 and 15 in which the axial crush deformation was stably generated when the load was input, the energy absorption performance was improved with respect to the structure 1. Further, as shown in Table 1 above, in the structures 6 to 10, the weight reduction ratio with respect to the structure 1 is also large. Therefore, according to the result of this simulation, when the distance between the reinforcing members is within the range of 0.74 to 1.84 times the minimum width W _{min in} the outer dimension of the hollow member, the weight reduction is achieved. At the same time, it is possible to stably generate axial crush deformation and improve the energy absorption performance.

Further, as shown in Table 1 above, in Structure 11, in addition to the horizontal bending of the hollow member, the weight reduction rate relative to Structure 1 is low and the energy absorption performance is not improved. That is, in the configuration according to the present invention, it can be said that it is not preferable to use the steel plate as the material of the reinforcing member.

Further, comparing Structures 12 to 14, when the plate thickness of the reinforcing member is 2.8 mm (Structure 12), the deformation mode is stable axial crushing, while the plate thickness of the reinforcing member is 0.6 mm. In some cases (Structure 13) or 3.2 mm (Structure 14) the deformation mode is unstable axial crush. That is, in the configuration according to the present invention, it can be said that the plate thickness of the CFRP member as the reinforcing member is preferably 0.8 mm to 2.8 mm.

Further, in the structure 15, GFRP is used as the material of the reinforcing member. In this case, the deformation mode is stable axial crushing, and the energy absorption performance is improved with respect to the structure 1. That is, it can be said that it is also effective to use GFRP as the material of the reinforcing member in the configuration according to the present invention.

Further, in the structure 16, the number of reinforcing members arranged in the hollow member is two. In this case, the deformation mode is lateral bending, and the energy absorption performance is not improved. That is, in the structure according to the present invention, it can be said that the number of reinforcing members to be arranged is preferably three or more.

The present invention can be applied to a structural member for vehicles.

1 frame 10 hollow member 10a hollow member front end 10b hollow member rear end 11a hollow member top surface portion 11b, 11d hollow member side surface portion 11c hollow member bottom surface portion 11e to 11h hollow member ridge line portion 20 reinforcing member 20a reinforcing member Plate surfaces 21a to 21d of the flange 30 of the reinforcing member Crash box 40 Bumper beam W _max Maximum width of the outer dimension of the hollow member W _min Minimum width of the outer dimension of the hollow member

To solve the above problems, according to the present invention, a hollow member made of metal, and each side is joined to an inner surface of the hollow member, and a member longitudinal direction of the hollow member so as to separate an inner space of the hollow member. A plurality of plate-shaped reinforcing members made of FRP disposed at intervals along the hollow member , wherein the hollow member is a member extending so that the longitudinal direction of the hollow member coincides with the vehicle traveling direction, In a cross section of the hollow member perpendicular to the member longitudinal direction, the minimum width of the hollow member in external dimensions is 30% or more of the maximum width of the hollow member in external dimensions, and each reinforcing member is Three or more sheets in a direction in which the plate surface is perpendicular to the member longitudinal direction of the hollow member and at an interval of 0.74 times to 1.84 times the minimum width from the end portion of the hollow member in the member longitudinal direction. There is provided a structural member for a vehicle, wherein the reinforcing member is disposed and the plate thickness of the reinforcing member is 0.7 to 3.0 mm.

Claims (7)

A hollow member made of metal,
A plate-like reinforcing member made of FRP, in which each side is joined to the inner surface of the hollow member, and a plurality of FRPs are arranged at intervals along the member longitudinal direction of the hollow member so as to separate the inner space of the hollow member. With and
In a cross section perpendicular to the member longitudinal direction of the hollow member, the minimum width of the hollow member in external dimensions is 30% or more of the maximum width of the hollow member in external dimensions,
Each reinforcing member has an orientation in which the plate surface of the reinforcing member is perpendicular to the member longitudinal direction of the hollow member, and from the end of the hollow member in the member longitudinal direction, 0.74 times the minimum width to 1. Three or more are arranged at 84 times the interval,
The structural member for a vehicle, wherein the reinforcing member has a plate thickness of 0.7 to 3.0 mm. The hollow member has a bend inducing portion in a part in the member longitudinal direction,
The vehicle structural member according to claim 1, wherein an interval between the reinforcing members arranged in the bending inducing portion is narrower than an interval between the reinforcing members arranged in a portion other than the bending inducing portion. The hollow member has a bend inducing portion in a part in the member longitudinal direction,
The vehicle structural member according to claim 1 or 2, wherein a plate thickness of the reinforcing member arranged in the bend inducing portion is thicker than a plate thickness of the reinforcing member arranged in a portion other than the bend inducing portion. The hollow member has a bend inducing portion in a part in the member longitudinal direction,
The tensile strength of the reinforcing member arranged in the bending inducing portion is larger than the tensile strength of the reinforcing member arranged in a portion other than the bending inducing portion. Vehicle structural member. The vehicle structural member according to any one of claims 1 to 4, wherein the FRP is CFRP or GFRP. The structural member for a vehicle according to any one of claims 1 to 5, wherein the hollow member has a tensile strength of 980 MPa or more. The vehicle structural member according to any one of claims 1 to 6, which is one of a front side member, a rear side member, an extension, and a crash box.

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