JP7107055B2 - Vehicle structural member - Google Patents

Description

The present invention relates to structural members for vehicles.

In recent years, from the viewpoint of protecting the global environment, there is a demand for improving the fuel efficiency of automobiles. On the other hand, maintenance or improvement of collision safety of vehicles is required. In order to satisfy these demands, the development of high-strength and lightweight car body structures is underway. Frames, which are structural members for vehicles and form the frame of the vehicle body, are also being made stronger and thinner in the steel sheets that form the frame in order to reduce the weight of the vehicle body structure while maintaining conventional collision performance. ing.

In addition, in order to improve the collision safety of a vehicle, it is required to improve the energy absorption performance of the front and rear portions of the vehicle, which are also called "crushable zones." For example, there is a part called a front side member in the front crushable zone. For example, at the time of a frontal collision of a vehicle, a load is input to the front side member mainly from the longitudinal direction (axial direction) of the member. Absorbing energy is preferred.

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

Japanese Patent Application Laid-Open No. 2004-182189

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

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

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to reduce the weight of a vehicle structural member while maintaining or improving the energy absorption performance at the time of a vehicle collision.

One aspect of the present invention for solving the above problems is a structural member for a vehicle, comprising: a metallic hollow member having a tensile strength of 980 MPa or more; a plurality of plate-shaped reinforcing members arranged at intervals along the member longitudinal direction of the hollow member so as to separate spaces, and a planar portion of the hollow member in a cross section perpendicular to the member longitudinal direction of the hollow member Assuming that the length is defined as the plane width, each reinforcing member is oriented so that the plate surface of the reinforcing member is perpendicular to the member longitudinal direction of the hollow member, and over the entire length of the member longitudinal direction of the hollow member It is characterized by being arranged at intervals of 0.5 times or more and 0.8 times or less of the minimum plane width of the hollow member.

In the vehicle structural member described above, it is possible to suppress the collapse of the cross section of the hollow member when a high load is input from the longitudinal direction of the member. As a result, the reaction force of the vehicle structural member when a load is input can be increased, and the energy absorption performance can be enhanced.

ADVANTAGE OF THE INVENTION According to this invention, it is a structural member for vehicles. WHEREIN: While achieving weight reduction, the energy absorption performance at the time of a vehicle collision can be maintained or improved.

1 is a perspective view showing a state in which a vehicle frame and another member are joined together according to an embodiment of the present invention; FIG. FIG. 4 is a plan view showing a state in which the vehicle frame and another member are joined together according to the same embodiment; FIG. 4 is a side view showing a state in which the vehicle frame and another member are joined together according to the same embodiment; It is a perspective view showing a schematic configuration of a vehicle frame according to the same embodiment. It is a perspective view which shows the shape of the reinforcing member which concerns on the same embodiment. FIG. 4 is a view showing a cross section of the vehicle frame according to the same embodiment perpendicular to the member longitudinal direction of the hollow member; FIG. 7 is a sectional view taken along line aa in FIG. 6; FIG. 7 is a cross-sectional view taken along the line bb in FIG. 6; FIG. 4 is a cross-sectional view of a hollow member for explaining an example of holes provided in the hollow member according to the same embodiment; FIG. 4 is a schematic diagram showing another example of holes provided in the hollow member according to the same embodiment; FIG. 4 is a schematic diagram showing another example of holes provided in the hollow member according to the same embodiment; FIG. 4 is a schematic diagram showing another example of holes provided in the hollow member according to the same embodiment; FIG. 4 is a schematic diagram showing another example of holes provided in the hollow member according to the same embodiment; FIG. 4 is a cross-sectional view of a hollow member for explaining an example of bead portions provided in the hollow member according to the same embodiment; FIG. 5 is a schematic diagram showing another example of recesses provided in the hollow member according to the same embodiment. FIG. 5 is a schematic diagram showing another example of recesses provided in the hollow member according to the same embodiment. FIG. 5 is a schematic diagram showing another example of recesses provided in the hollow member according to the same embodiment. FIG. 5 is a schematic diagram showing another example of recesses provided in the hollow member according to the same embodiment. FIG. 5 is a schematic diagram showing another example of recesses provided in the hollow member according to the same embodiment. FIG. 5 is a cross-sectional view of a hollow member for explaining an example of convex portions provided on the hollow member according to the same embodiment; FIG. 10 is a schematic diagram showing another example of a convex portion provided on the hollow member according to the same embodiment; FIG. 10 is a schematic diagram showing another example of a convex portion provided on the hollow member according to the same embodiment; FIG. 10 is a schematic diagram showing another example of a convex portion provided on the hollow member according to the same embodiment; FIG. 10 is a schematic diagram showing another example of a convex portion provided on the hollow member according to the same embodiment; FIG. 10 is a schematic diagram showing another example of a convex portion provided on the hollow member according to the same embodiment; FIG. 4 is a schematic diagram showing an example of a plate thickness changing portion provided in the hollow member according to 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. 4 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; FIG. 5 is a schematic diagram showing another example of a different strength portion provided in the hollow member according to the same embodiment. FIG. 5 is a schematic diagram showing another example of a different strength portion provided in the hollow member according to the same embodiment. FIG. 4 is a schematic diagram showing an example of a strength varying portion provided in the hollow member according to the same embodiment; FIG. 11 is a plan view showing a deformed state of the vehicle frame of the comparative example (structure 2); FIG. 33 is a cross-sectional view of the hollow member along the cc cross section in FIG. 32; FIG. 33 is a cross-sectional view of the hollow member taken along line dd in FIG. 32; FIG. 11 is a plan view showing a deformed state of the vehicle frame of the comparative example (structure 3); FIG. 36 is a cross-sectional view of the hollow member along the cc cross section in FIG. 35; FIG. 36 is a cross-sectional view of the hollow member taken along line dd in FIG. 35; FIG. 11 is a plan view showing a deformed state of the vehicle frame of the invention example (structure 5); FIG. 39 is a cross-sectional view of the hollow member along the cc cross section in FIG. 38; FIG. 39 is a cross-sectional view of the hollow member taken along line dd in FIG. 38; FIG. 4 is a diagram comparing 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 drawings, elements having substantially the same functional configuration are denoted by the same reference numerals, thereby omitting redundant description.

<1. Application target of vehicle structural member>
Before describing the configuration of a vehicle frame, which 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 mitigating the impact on the vehicle (impact absorbing function) by collapsing themselves in the event of a vehicle collision. That is, in order to ensure the safety of passengers in the cabin in the event of a vehicle collision, the front structure and the rear structure are required to absorb as much energy as possible due to the collision (collision energy). Therefore, the frames forming the front structure and the rear structure are required to absorb a large amount of collision energy even when they are bent or crushed at the time of collision. The frames used for the front structure and the rear structure are, for example, front side members and rear side members. The front side member includes a front side member barrier forming a rear end portion and a front side member front forming a portion on the front side of the rear end portion. The rear side member includes a rear side member barrier forming a rear end portion and a rear side member front forming a portion on the front side of the rear end portion.

By the way, in order to achieve both the maintenance of collision safety and weight reduction of vehicles, steel sheets forming the vehicle body structure are being strengthened and thinned. The frames constituting the front structure, the rear structure, and the cabin structure are also being replaced with thin, high-strength steel plates. Specifically, the thickness of the frame made of high-strength steel plate is set to be greater than that of the conventional steel plate so that at least one of the amount of collision energy absorption and load bearing performance is equivalent to that of the frame made of conventional steel plate. It is set thinner than the frame to be formed. As a result, the weight of the frame can be reduced while maintaining the collision performance of the high-strength frame equivalent to that of the conventional frame.

<2. Configuration of Vehicle Frame>
(frame component)
FIG. 1 is a perspective view showing a state in which a vehicle frame 1 according to one embodiment of the present invention is joined to another member. 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 a bumper beam 40 via a crash box 30. As shown in FIG. Normally, two front side members are arranged symmetrically in front of the cabin, and FIGS. 1 to 3 show only one of them. The vehicle frame 1 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 members relating to the front structure and the rear structure, but it is also possible to apply the vehicle frame 1 to members relating to the cabin structure. Further, the vehicle structural member can be applied not only to automobiles 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 tractors, trailers, railroad vehicles, construction machinery, mining machinery, agricultural machinery, general machinery, and ships.

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

The hollow member 10 of the present embodiment is an example of a long structural member, and is a member having a rectangular cross section perpendicular to the longitudinal direction of the member (the X direction in the present embodiment). The hollow member 10 of the present embodiment is a rectangular tubular member formed as a single piece, and the hollow member 10 is formed by joining a flat plate-like closing plate and a member having a hat-shaped cross section, for example. may be That is, the configuration of the hollow member 10 is not particularly limited as long as the cross section perpendicular to the member longitudinal direction X is a closed cross section. For example, in the present embodiment, the hollow member 10 has a rectangular shape, which is an example of a polygonal shape, but the hollow member 10 may have a polygonal shape other than a rectangle.

As shown in FIG. 6, the hollow member 10 of this embodiment has four plane portions 11a to 11d. In the following description, of the four plane portions 11a to 11d, the plane portion located on the upper side in FIG. The plane portion located on the left side of the bottom portion 11c is called a side portion 11d. In addition, a ridgeline portion 11e is a connection portion between the flat surface portions 11a and 11b, which is a portion which is a boundary between the top surface portion 11a and the side surface portion 11b, and both flat surface portions 11b which is a portion which is a boundary between the side surface portion 11b and the bottom surface portion 11c. , 11c is a ridgeline portion 11f, the connection portion of both plane portions 11c and 11d as a boundary between the bottom surface portion 11c and the side surface portion 11d is a ridgeline portion 11g, and the connection portion between the side surface portion 11d and the top surface portion 11a is a ridgeline portion 11g. A connecting portion between the flat portions 11d and 11a is called a ridgeline portion 11h.

The hollow member 10 is made of a metal plate. Although the type of metal plate is not particularly limited, it is preferably formed of 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 for frame structures that are often used in large vehicles such as buses, and 3.0 mm for monocoque structures that are often used in normal size vehicles. It is preferably 2 mm or less. Moreover, the 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 compensate for the overall strength of the frame 1 that may be reduced due to weight reduction. Further, it is more preferable that the tensile strength of the hollow member 10 is 980 MPa or more.

The reinforcing member 20 is formed in a plate shape, and flanges 21a to 21d are formed on straight portions of a 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 orientation. The flange 21a of the reinforcing member 20 is attached to the inner surface of the top surface portion 11a of the hollow member 10, the flange 21b is attached to the inner surface of the side surface portion 11b of the hollow member 10, the flange 21c is attached to the inner surface of the bottom surface portion 11c of the hollow member 10, and the flange 21d is hollow. They are joined to the inner surfaces of the side portions 11d of the member 10, respectively. The reinforcing member 20 is thereby 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 longitudinal direction X of the member. The shape of the reinforcing member 20 is appropriately changed according to the shape of the hollow member 10, the joining method with the hollow member 10, etc. so that the reinforcing member 20 functions as a bulkhead.

(Example of reinforcing member)
An FRP member that can be used as a reinforcing member means a fiber-reinforced resin member composed of a matrix resin and a composite reinforcing fiber material contained in the matrix resin.

As the reinforcing fiber material, for example, carbon fiber and glass fiber can be used. In addition, boron fiber, silicon carbide fiber, aramid fiber, etc. can be used as the reinforcing fiber material. In the FRP used for the FRP member, the reinforcing fiber base material, which is the base material of the reinforcing fiber material, includes, for example, a nonwoven fabric base material using chopped fibers, a cloth material using continuous fibers, a unidirectional reinforcing fiber base material (UD material) etc. can be used. These reinforcing fiber substrates can be appropriately selected depending on the orientation of the reinforcing fiber material.

A CFRP member is an FRP member using carbon fiber as a reinforcing fiber material. For example, PAN-based or pitch-based carbon fibers can be used. By using carbon fiber, strength against weight can be efficiently improved.

A GFRP member is an FRP member using glass fiber as a reinforcing fiber material. It is inferior to carbon fiber in mechanical properties, but can suppress electric corrosion of metal members.

Both thermosetting resins and thermoplastic resins can be used as matrix resins used in FRP members. Thermosetting resins include epoxy resins, unsaturated polyester resins, vinyl ester resins, and the like. Thermoplastic resins 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, polycarbonates, and polyethersulfones. , polyphenylene ether and modified products thereof, polyarylates, polyetherketones, polyetheretherketones, polyetherketoneketones, styrene resins such as vinyl chloride and polystyrene, and phenoxy resins. In addition, the matrix resin may be formed of a plurality of types of resin materials.

Considering application to metal members, 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. In addition, since the phenoxy resin has a similar molecular structure to that of the epoxy resin, which is a thermosetting resin, it has heat resistance equivalent to that of the epoxy resin. Moreover, by further adding a curing component, application to a high-temperature environment becomes possible. When a hardening component is added, the amount to be added may be appropriately determined in consideration of the impregnating properties of 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 is formed of an FRP member or the like, an adhesive resin layer is provided between the FRP member and the metal member (the 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 type of 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. For example, thermoplastic resins include polyolefins and acid-modified products thereof, polystyrene, polymethyl methacrylate, AS resins, ABS resins, thermoplastic aromatic polyesters such as polyethylene terephthalate and polybutylene terephthalate, polycarbonates, polyimides, polyamides, and polyamides. Use one or more selected from imide, polyetherimide, polyethersulfone, polyphenylene ether and modified products thereof, polyphenylene sulfide, polyoxymethylene, polyarylate, polyetherketone, polyetheretherketone, and polyetherketoneketone, etc. can do. As the thermosetting resin, for example, one or more selected from epoxy resins, vinyl ester resins, phenol resins, and urethane resins can be used.

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

By bonding the FRP member to the metal member using the adhesive resin layer described above, the adhesion between the FRP member and the metal member can be improved. By doing so, it is possible to improve the deformation followability of the FRP member when a load is input to the metal member. In this case, the effect of the FRP member on the deformed body of the metal member can be exhibited more reliably.

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

A crosslinkable adhesive resin composition may also be formed by blending a crosslinkable curable resin and a crosslinker with the 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 cross-linkable curable resin, for example, a bifunctional or higher functional epoxy resin or a crystalline epoxy resin can be used. Amines, acid anhydrides, and the like can also be used as cross-linking agents. In addition, the adhesive resin composition may contain other additives such as various rubbers, inorganic fillers, solvents, etc., as long as the adhesiveness and physical properties are not impaired.

Combining the FRP member with the metal member is realized by various methods. For example, it can be obtained by bonding an FRP to be an FRP member or an FRP molding prepreg that is a precursor thereof and a metal member with the adhesive resin composition described above and solidifying (or curing) the adhesive resin composition. . In this case, the FRP member and the metal member can be combined by, for example, thermocompression bonding.

Adhesion of the FRP or FRP molding prepreg to the metal member may be performed before, during or after molding of the part. For example, after molding a metal material, which is a work material, into a metal member, FRP or a prepreg for FRP molding may be adhered to the metal member. Also, after bonding FRP or FRP molding prepreg to a work material by thermocompression bonding, 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 where the FRP member is adhered. In addition, when the matrix resin of the FRP member is a thermoplastic resin, composite batch molding may be performed in which the thermocompression bonding process and the molding process are integrated.

It should be noted that the method of joining the FRP member and the metal member is not limited to adhesion using the adhesive resin layer described above. For example, the FRP member and metal member may be mechanically joined. More specifically, fastening holes are formed in corresponding positions of the FRP member and the metal member, and the FRP member and the metal member are fastened by fastening means such as bolts and rivets through the holes. The member may be joined. Alternatively, the FRP member and the metal member may be joined by a known joining means. Also, the FRP member and the metal member may be joined in a composite manner by a plurality of joining means. For example, adhesion by the adhesive resin layer and fastening by fastening means may be used in combination.

Various materials other than the FRP member can be used as the reinforcing member. For example, the reinforcing member may be made of a resin composition other than the resin composition described above, such as a foaming resin made of rigid polyurethane foam or the like. Also, the reinforcing member may be a steel material, an aluminum alloy member, a magnesium alloy member, or the like. Also, the joining method to the metal member is not limited to welding, and various appropriate joining methods can be used.

(Metal member and its surface treatment)
The metal member according to the present invention may be plated. This improves corrosion resistance. In particular, it is more suitable when the metal member is steel. The type of plating is not particularly limited, and known plating can be used. For example, galvanized steel sheets (steel materials) include hot-dip galvanized steel sheets, hot-dip alloyed galvanized steel sheets, Zn-Al-Mg-based alloy-plated steel sheets, aluminum-plated steel sheets, electro-galvanized steel sheets, electro-Zn-Ni-based alloy-plated steel sheets, and the like. can be used.

In addition, the surface of the metal member may be coated with a film called chemical conversion treatment. This further improves corrosion resistance. As the chemical conversion treatment, generally known chemical conversion treatments can be used. For example, zinc phosphate treatment, chromate treatment, chromate-free treatment, or the like can be used as the chemical conversion treatment. Further, the film may be a known resin film.

Also, the metal member may be coated with a generally known coating. This further improves corrosion resistance. A known resin can be used as the coating. For example, as the coating, a coating made mainly of epoxy resin, urethane resin, acrylic resin, polyester resin, fluorine-based resin, or the like can be used. In addition, generally known pigments may be added to the coating as needed. Also, 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 compositing the FRP member, or may be applied to the metal member after compositing the FRP member. Alternatively, the metal member may be coated in advance, then the FRP member may be composited, and then coated. The paint used for coating may be a solvent-based paint, a water-based paint, a powder paint, or the like. As a coating method, a generally known method can be applied. For example, as a coating method, electrodeposition coating, spray coating, electrostatic coating, dip coating, or the like can be used. Electrodeposition coating is suitable for coating end faces and gaps of metal members, and is therefore excellent in corrosion resistance after coating. Further, 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, the coating film adhesion is improved.

<3. Arrangement example of reinforcing member>
As shown in FIG. 4, the plurality of reinforcing members 20 are arranged at intervals over the entire length in the member longitudinal direction X from the end of the hollow member 10 in the member longitudinal direction X. As shown in FIG. More specifically, 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, as shown in FIGS. are placed at

Here, in this specification, the length of the plane portion of the hollow member 10 in the cross section perpendicular to the member longitudinal direction X (the length of the straight portion in the cross section) is defined as the "plane width". In the case of this embodiment, the length of the top surface portion 11a in the cross section shown in FIG. The length of the bottom portion 11c is the plane width of the bottom portion 11c, and the length of the side portion 11d in the cross section is the plane width of the side portion 11d. In the hollow member 10 of this embodiment, the plane width of the top portion 11a and the plane width of the bottom portion 11c are equal to each other, and the plane widths of the pair of side portions 11b and 11d are equal to each other. In addition, the plane widths of the top surface portion 11a and the bottom surface portion 11c are shorter than the plane widths of the pair of side portions 11b and 11d.

The interval P between the reinforcing members 20 arranged inside the hollow member 10 is 0.8 times or less the minimum plane width W _min of the plane widths of the hollow member 10 . That is, in the present embodiment, among the plane widths of the plane portions 11a to 11d of the hollow member 10, the interval is 0.8 times or less of the plane width _Wmin of the top plane portion 11a and the bottom plane portion 11c, which is the shortest plane width. P, each reinforcing member 20 is arranged along the member longitudinal direction X of the hollow member 10 . The “minimum plane width W _min ” means the shortest plane width under conditions other than plane widths of 10% or less of the maximum plane width W _max . For example, in the cross section shown in FIG. 6, the plane width of the pair of side portions 11b and 11d is the _maximum plane width _Wmax . If there is, the shortest plane width among the plane widths other than the top surface portion 11a becomes the _minimum plane width Wmin. In addition, in the case of the hollow member 10 having a shape in which the plane width changes in the member longitudinal direction X, the minimum plane width W Define _min .

As will be described later in Examples, when the spacing P between the reinforcing members 20 is 0.8 times or less the _minimum plane width Wmin of the hollow member 10, a high load is input from the member longitudinal direction X of the hollow member 10. It is possible to suppress the collapse of the cross section of the hollow member 10 when the hollow member 10 is formed. As a result, the reaction force of the frame 1 when a load is input can be increased, and the energy absorption performance can be improved. Further, since the degree of improvement in energy absorption performance is large, the thickness of the hollow member 10 can be reduced, and the weight of the frame 1 as a whole can also be reduced. Therefore, according to the frame 1 of the present embodiment, weight reduction can be achieved and energy absorption performance can be maintained or improved.

Also, the interval P between the reinforcing members 20 is preferably less than 0.8 times the minimum planar width W _min of the hollow member 10, and more preferably 0.5 times or less. Thereby, the energy absorption performance of the frame 1 can be further enhanced. Although the lower limit of the spacing P between the reinforcing members 20 is not particularly limited, it is inevitably determined according to the shape of the reinforcing member 20 . For example, when the hollow member 10 and the reinforcing member 20 are joined by the flanges 21a to 21d of the reinforcing member 20 as in the present embodiment, the interval P between the reinforcing members 20 is the longitudinal direction of the flanges 21a to 21d. It is determined according to the length of X.

Moreover, from the viewpoint of increasing the weight efficiency of the energy absorption performance, the plate thickness of the reinforcing member is preferably 0.6 mm or less. Moreover, from the same point of view, the tensile strength of the reinforcing member is preferably 440 MPa or more.

In the present embodiment, the _spacing P between the reinforcing members 20 is constant along the member longitudinal direction X of the hollow member 10. If so, the spacing P between the reinforcing members 20 may not be constant along the longitudinal direction X of the members. For example, the shape of the hollow member 10 is appropriately changed according to the use of the vehicle structural member. By changing the interval P of 20, the plate thickness, the strength, etc., it is possible to selectively reinforce the portion where bending deformation is likely to occur. Thereby, the collapse of the cross section of the hollow member 10 can be effectively suppressed. In this specification, a portion where such bending deformation is likely to occur is called a "bending-inducing portion".

It is preferable that the interval P between the reinforcing members 20 in the bending-inducing portion is narrower than the interval P between the reinforcing members 20 in the portion other than the bending-inducing portion. As a result, it is possible to effectively suppress the collapse of the cross section in the bending induction portion, and to further improve the energy absorption performance. For the same reason, the thickness of the reinforcing member 20 in the bending-inducing portion is preferably greater than the thickness of the reinforcing member 20 in the portion other than the bending-inducing portion. For the same reason, it is preferable that the tensile strength of the reinforcing member 20 in the bending-inducing portion is greater than the tensile strength of the reinforcing member 20 in the portion other than the bending-inducing portion. In addition, the adjustment of the spacing P, the plate thickness and the tensile strength as described above may be combined as appropriate, thereby effectively suppressing the collapse of the cross section in the bending induction portion and further improving the energy absorption performance. It becomes possible.

<4. Example of bending induction part>
Next, an example of a bend inducing portion provided in the hollow member 10 will be described. For example, holes, recesses, protrusions, plate thickness change portions, different strength portions, and the like provided in the hollow member 10 function as bending induction portions. The portion provided with any one of the hole portion, the recessed portion, the convex portion, and the plate thickness change portion is the portion where the section modulus of the hollow member 10 changes in the member longitudinal direction X of the hollow member 10 . At the portion where the section modulus of the hollow member 10 changes in the longitudinal direction X of the member, the bending stress generated in the hollow member 10 changes due to the same bending moment, so bending of the hollow member 10 is induced at that portion. More specifically, a portion of the hollow member 10 having a relatively small section modulus in the member longitudinal direction X has a relatively large bending stress, so that bending occurs at that portion. In addition, for a portion of the hollow member 10 in the member longitudinal direction X where the section modulus is relatively large, the section modulus of the portion including the front and rear regions of the hollow member 10 in the member longitudinal direction X of the portion has a relatively small section modulus. . Therefore, bending occurs at the boundary portion between the region and the portion having a relatively large section modulus.

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 . At a portion where the yield strength changes in the member longitudinal direction X of the hollow member 10, plastic deformation of the hollow member 10 is induced at that portion. For example, at a portion of the hollow member 10 where the yield strength is relatively low in the member longitudinal direction X, plastic deformation occurs first in the hollow member 10, so bending occurs at that portion. In addition, for a portion of the hollow member 10 in which the yield strength is relatively large in the member longitudinal direction X, the yield strength of the portion including the regions before and after the member longitudinal direction X of the hollow member 10 of the portion is relatively small. . Therefore, bending occurs at the boundary portion between the region and the portion where the yield strength is relatively high.

In addition, even if the hollow member 10 does not have a portion including a hole portion, a recessed portion, a convex portion, a plate thickness change 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 If the input direction can be specified to some extent, there will be a region where the bending moment is maximum within the hollow member under the influence of the restraints of the peripheral members joined to the hollow member 10, and bending will occur in this 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 induction portion.

A specific example of the bending induction portion provided in the hollow member 10 will be described below.

(Hole)
FIG. 9 is a cross-sectional view of the hollow member 10A for explaining an example of holes provided in the hollow member 10A according to this embodiment. As shown in FIG. 9, a hole portion 50 is provided in the side portion 11b. The section modulus of the hollow member 10A at the portion where the hole portion 50 is provided is lower than the section modulus of the hollow member 10A at the portions before and after the portion where the hole portion 50 is provided. Therefore, when the collision load F shown in FIG. 9 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 provided with the hole portion 50 serves as the bending induction portion provided in the hollow member 10A.

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

Further, as shown in FIG. 12, a hole portion 50c extending in a direction crossing the member longitudinal direction X of the hollow member 10A may be provided in the side surface portion 11b. In this case, when a collision load is input, the hollow member 10A is bent toward the side surface portion 11b with the hole portion 50c as the starting point of bending. The shape of the hole portion 50c is not limited to the rounded rectangle shown in FIG. 12, and may be any shape. The direction crossing the member longitudinal direction X of the hollow member 10A described above is not limited to the direction perpendicular to the member longitudinal direction X of the hollow member 10A as shown in FIGS.
Further, the portion where the hole portion 50 is provided is not limited to the side surface portion 11b. For example, the hole portion 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. 13, a hole portion 50d may be provided in the ridgeline portion 11e. As a result, the section modulus of the portion of the hollow member 10A provided with the hole portion 50d in the longitudinal direction X of the member is significantly reduced, so that the portion provided with the hole portion 50d becomes a starting point of bending and is easily deformed.

(recess)
FIG. 14 is a cross-sectional view of a hollow member 10B for explaining an example of bead portions provided in the hollow member according to this embodiment. Note that the bead portion 51 is an example of the recess in this embodiment. As shown in FIG. 14, a bead portion 51 is provided on the side portion 11b. The section modulus of the hollow member 10B at the portion where the bead portion 51 is provided is lower than the section modulus of the hollow member 10B at the portions before and after the portion where the bead portion 51 is provided. Therefore, when the collision load F shown in FIG. 14 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 serves as the bending induction portion provided in the hollow member 10B.

Note that the shape and arrangement of the recesses are not limited to the examples described above. 15 to 18 are schematic diagrams showing other examples of recesses provided in the hollow member 10B according to this embodiment. The term "recessed portion" as used herein means a depressed portion, such as an emboss or bead, provided in the side surface portion 11b of the hollow member 10B or the like. As shown in FIG. 15, a circular recess 51a may be provided in the side surface portion 11b.

Also, as shown in FIG. 16, a plurality of recesses 51b may be provided in the side surface portion 11b. In this case, for example, a plurality of recesses 51b may be provided side by side in a direction crossing the member longitudinal direction X of the hollow member 10B. In this case, when a collision load is input, the plurality of concave portions 51b serve as starting points for bending, and the hollow member 10B is easily bent toward the side surface portion 11b.

Further, as shown in FIG. 17, a bead portion 51c extending in a direction crossing the member longitudinal direction X of the hollow member 10B may be provided on the side surface portion 11b. In this case, when a collision load is input, the hollow member 10B is bent toward the side surface portion 11b with the bead portion 51c as a starting point of bending. The shape of the bead portion 51c is not limited to the rounded rectangle shown in FIG. 17, and may be any shape.
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 recessed 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. 18, a recess 51d may be provided in the ridgeline portion 11e. As a result, the section modulus of the portion of the hollow member 10B provided with the recess 51d changes significantly in the longitudinal direction X of the member, so that the portion provided with the recess 51d becomes a starting point of bending and is easily deformed.

FIG. 19 is a schematic diagram showing another example of recesses provided in the hollow member 10B according to this embodiment. As shown in FIG. 19, concave portions 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, bending occurs in a portion 510 between the concave portion 51e and the concave portion 51f in the member longitudinal direction X of the hollow member 10B. That is, since the section modulus of the hollow member 10B provided with the recesses 51e and 51f and the section 510 between the recesses 51e and 51f are different, the section 510 is bent when a collision load is applied. Bending deformation occurs as the origin of 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. Note that the recess 51e and the recess 51f do not necessarily have to be arranged in series as shown in FIG. Further, the recessed portion 51e and the recessed portion 51f do not necessarily have to extend in the member longitudinal direction X of the hollow member 10B.

(Convex part)
FIG. 20 is a cross-sectional view of the hollow member 10C for explaining an example of convex portions provided on the hollow member 10C according to this embodiment. As shown in FIG. 20, a convex portion 52 is provided on the side portion 11b. The section modulus of the hollow member 10C at the portion where the protrusion 52 is provided is higher than the section modulus of the hollow member 10C at the portions before and after the portion at which the protrusion 52 is provided. Therefore, when the collision load F shown in FIG. 20 is input to the hollow member 10C, in the region 6a or region 6b before and after the convex portion 52 in the member longitudinal direction X of the hollow member 10C, the section modulus is the lowest. , the convex portion 52 is bent on the inner side. The regions 6a and 6b are regions in which the section modulus of the hollow member 10C changes in the Y direction. That is, in the member longitudinal direction X of the hollow member 10C, a portion of the hollow member 10C including the convex portion 52 and the regions 6a and 6b before and after the convex portion 52 serves as a bending induction portion provided in the hollow member 10C.

In the example shown in FIG. 20, the convex portion 52 is provided on the side surface portion 11b, but the convex portion 52 may be provided on 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 of a part of the hollow member 10C in the member longitudinal direction X, the hollow member 10C is Since the section modulus in the member longitudinal direction X changes at the portion where the convex portion 52 is provided, bending of the hollow member 10C may occur at the portion where the convex portion 52 is provided. Therefore, in this case as well, the convex portion 52 serves as a bend-inducing portion.

Moreover, the shape and arrangement of the protrusions are not limited to the examples described above. 21 to 24 are schematic diagrams showing other examples of convex portions provided on the hollow member 10C according to this embodiment. The convex portion referred to 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. 21, a circular protrusion 52a may be provided on the side surface portion 11b.

Also, as shown in FIG. 22, a plurality of protrusions 52b may be provided on the side surface portion 11b. In this case, for example, a plurality of protrusions 52b may be provided side by side in a direction crossing the member longitudinal direction X of the hollow member 10C. In this case, when a collision load is input, the hollow member 10C is likely to bend and deform toward the side surface portion 11b with any of the regions before and after the plurality of convex portions 52b in the member longitudinal direction X of the hollow member 10C as the starting point of bending. Become.

Further, as shown in FIG. 23, a convex portion 52c extending in a direction transverse to the member longitudinal direction X of the hollow member 10C may be provided on the side surface portion 11b. In this case, when a collision load is input, the hollow member 10C is bent toward the side surface portion 11b with any 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. 23, 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 perpendicular 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. 24, a convex portion 52d may be provided on the ridgeline portion 11e. As a result, the section modulus of the portion of the hollow member 10C provided with the convex portion 52d changes significantly in the longitudinal direction X of the member, so that the portion provided with the convex portion 52d becomes a starting point of bending and is easily deformed.

FIG. 25 is a schematic diagram showing another example of the convex portion provided on the hollow member 10C according to this embodiment. As shown in FIG. 25, 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, bending occurs at a portion 520 between the projections 52e and 52f in the member longitudinal direction X of the hollow member 10C. That is, of the hollow member 10C, the section provided with the protrusions 52e and 52f and the section 520 between the protrusions 52e and 52f have different section moduli. Bending deformation occurs with 520 as the starting point of bending. Further, the portion 520 may be formed with the above-described concave portions, convex portions, thin-walled portions, different-strength portions, or the like, which will be described later. 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, the side surface portion 11b may be provided with a plate thickness changing portion as a configuration for realizing the bending inducing portion. FIG. 26 is a schematic diagram showing an example of a plate thickness changing portion provided in the hollow member 10D according to this embodiment. The plate thickness change portion referred to here means a portion where the plate thickness changes in the member longitudinal direction X of the hollow member 10D. As shown in FIG. 26, the hollow member 10D includes a first thick plate portion 111 and a second thick plate portion 112. As shown in FIG. The first thick plate portion 111 is provided on the end portion side of the hollow member 10D, and the second thick plate portion 112 is provided continuously with the first thick plate portion 111 along the member longitudinal direction X of the hollow member 10D. The plate thickness of the steel plate differs between the first plate thickness portion 111 and the second plate thickness portion 112 . There are no particular restrictions on the size relationship of the plate thickness.

In this case, as shown in FIG. 26 , the boundary portion between the first plate thickness portion 111 and the second plate thickness portion 112 becomes the plate thickness change portion 113 . The section modulus of the hollow member 10</b>D in the member longitudinal direction X changes at the plate thickness changing portion 113 . That is, the plate thickness changing portion 113 corresponds to the bending induction portion. Therefore, when a collision load is input to the hollow member 10D, the hollow member 10D bends at the plate thickness changing portion 113. As shown in FIG.

Also, the bend-inducing portion may be realized by, for example, a thin-walled portion. FIG. 27 is a schematic diagram showing an example of the thin portion provided in the hollow member 10D according to this embodiment. As shown in FIG. 27, the side surface portion 11b is provided with a thin portion 114 having a thickness relatively smaller than that of other portions in the longitudinal direction X of the hollow member 10D. The section modulus of the hollow member 10D in the portion including the thin portion 114 is lower than the section 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 provided with the thin portion 114 corresponds to the bending induction portion. Therefore, when a 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 inner side of the bend.

The hollow member 10D having such plate thickness change portions may be formed from a work plate that is cut, pressed, and made from a tailored blank, for example. Such a work plate may be a Tailor Welded Blank (TWB) having weld seams. Further, the plate to be processed may be a tailor rolled blank (TRB) provided with different plate thicknesses by rolling rolls. In the TWB, the thickness difference at the plate thickness change portion can be 0.2 mm or more. Further, in the TRB, the amount of plate thickness change in the plate thickness changing portion per longitudinal direction of the member can be 0.1 mm/100 mm or more.

(Different strength part / strength change part)
FIG. 28 is a cross-sectional view of the hollow member 10E for explaining an example of different strength portions provided in the hollow member 10E according to this embodiment. As shown in FIG. 28, a different strength portion 53 is provided on the side 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 where the different strength portion 53 is provided differs from the yield strength of the hollow member 10E in the portions before and after the portion where the different strength portion 53 is provided. Therefore, when the collision load F shown in FIG. 28 is input to the hollow member 10E, the different strength portion 53 bends at or near the different strength portion 53 so that the different strength portion 53 is bent inside. 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 serves as the bending induction portion provided in the hollow member 10E. This bending is caused by plastic deformation of the different strength portion 53 or a region in the vicinity of the different strength portion 53 .

In the example shown in FIG. 28, 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 on the top surface portion 11a, the bottom surface portion 11c, or the side surface portion 11d on a part of the same cross section in the member longitudinal direction X of the hollow member 10, on the cross section , the strength of the side surface portion 11b is the lowest. As a result, bending of the hollow member 10E with the side surface portion 11b as the bending inner side may occur at the different strength portion 53 . Therefore, also in this case, the different-strength portion 53 serves as a bending-inducing portion.

Also, the arrangement of the different strength portions is not limited to the example described above. FIGS. 29 and 30 are schematic diagrams showing other examples of different strength portions provided in the hollow member 10E according to this embodiment. The different-strength portion referred to here is realized by welding, heat treatment, or the like to the plate to be processed that forms the hollow member 10E.

As shown in FIG. 29, a different strength portion 120 is provided along the cross-sectional circumferential direction with respect to the member longitudinal direction X of the hollow member 10E. In this case also, the portion of the hollow member 10E provided with the different strength portion 120 corresponds to the bending induction portion. Therefore, when a 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.

In addition, as shown in FIG. 30, for example, the different strength portion may be partially provided in 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 a collision load is input to the hollow member 10E, the hollow member 10E bends at the portion where the different strength portion 121 is provided so that the different strength portion 121 is on the inside of the bend.

Also, the bending induction portion may be implemented by, for example, a strength change portion. FIG. 31 is a schematic diagram showing an example of a strength changing portion provided in the hollow member 10E according to this embodiment. As shown in FIG. 31, the hollow member 10E includes a first strength portion 122 and a second strength portion 123. As shown in FIG. The first strength portion 122 is provided on the end portion 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 plate 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. 31 , the boundary portion between the first strength portion 122 and the second strength portion 123 becomes the strength change portion 124 . The yield strength in the member longitudinal direction X of the hollow member 10E changes at the strength changing portion 124 . That is, the strength changing portion 124 corresponds to the bending induction portion. Therefore, when a collision load is input to the hollow member 10E, the hollow member 10E bends at the strength change portion 124. As shown in FIG.

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

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 belongs can conceive of various modifications or modifications within the scope of the technical idea described in the claims. It is understood that these also naturally belong to the technical scope of the present invention.

A crash 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, and the hollow member has a rectangular cross section. A plurality of analytical models were created under the conditions shown in Table 1 below. The weight reduction rate in Table 1 is obtained by standardizing the weight of each structure by the weight of Structure 1.

Structures 1 and 2 in Table 1 above are structures in which the reinforcing member 20 is not provided, and Structure 2 is made thinner and higher in strength than Structure 1. Structures 3 to 9 are structures in which a plurality of reinforcing members 20 as shown in FIG. The tensile strength of the steel plate used as the material of the reinforcing member in Structures 3 to 6, Structures 8 and 9 is 440 MPa. In addition, the mechanical properties of CFRP used as the material of the reinforcing member in structure 7 are as follows.
Vf (fiber content volume fraction): 50%
Young's modulus: 102 GPa
Breaking strength: 1500MPa
Elongation at break: 1.5%

This simulation simulated a frontal collision test of an automobile, and was carried out by colliding a rigid wall with a mass of 200 kg against the bumper beam 40 shown in FIGS. 1 to 3 at 12 m/s. Note that the rear end 10b of the hollow member 10 in each analysis model is constrained.

32 is a plan view showing the deformation state of the analysis model of Structure 2 in the collision simulation, FIG. 33 is a cross-sectional view of the hollow member along the cc cross section in FIG. d is a cross-sectional view of the hollow member in section d. Structure 2 is a structure in which no reinforcing member is provided, and as shown in FIGS. 33 and 34, the hollow member deforms while collapsing its cross section, that is, collapsing or expanding at the break point. Such deformation of the hollow member also occurred in Structure 1.

35 is a plan view showing the deformation state of the analysis model of structure 3 in the collision simulation, FIG. 36 is a cross-sectional view of the hollow member along the cc cross section in FIG. d is a cross-sectional view of the hollow member in section d. Structure 3 is a structure provided with a reinforcing member, but as shown in FIGS. 36 and 37, the hollow member deformed while collapsing its cross section, that is, collapsing or expanding at the break point. Such deformation of the hollow member also occurred in Structure 4.

On the other hand, FIG. 38 is a plan view showing the deformation state of the analysis model of structure 5 in the collision simulation, FIG. FIG. 4 is a cross-sectional view of the hollow member taken along line dd. Structure 5 is a structure provided with reinforcing members similar to Structures 3 and 4, but as shown in FIGS. It was deformed in a state in which collapse was suppressed. Such deformation of the hollow member also occurred in Structures 6-9.

Next, from the load-stroke diagram when the rigid wall is colliding, the amount of energy absorbed by the rigid wall at a stroke of 700 mm was calculated, and the energy absorption performance of each analysis model was compared. The results are shown in FIG. Note that the vertical axis of the graph in FIG. 41 is the ratio of the energy absorption amount in each structure to the energy absorption amount in structure 1 .

As shown in FIG. 41 , structures 5 and 6 in which reinforcing members are arranged have improved energy absorption performance compared to structure 1 . Also, the energy absorption performance in structures 5 and 6 is improved over the energy absorption performance in structures 3 and 4 in which reinforcing members are arranged. As shown in Table 1 above, in Structures 5 and 6, the spacing between the reinforcing members is narrower than in Structures 3 and 4. According to the results of this simulation, it can be seen that when the spacing between the reinforcing members is 0.8 times or less the minimum planar width W _min of the hollow member, better energy absorption performance is exhibited. In addition, as shown in Table 1 above, Structures 5 and 6 have a greater weight reduction rate than Structure 1. Therefore, structural members for vehicles such as Structures 5 and 6 are advantageous in reducing weight while reducing energy consumption. Absorption performance can be improved.

Structure 7 is an analysis model using a CFRP member as a reinforcing member, and as shown in FIG. Also in the case of structure 7, since the weight reduction rate is large compared to structure 1, even in a vehicle structural member such as structure 7 provided with a reinforcing member made of CFRP, energy absorption performance is improved while achieving weight reduction. be able to.

In addition, the hollow members of Structures 8 and 9 are thinner than the hollow member of Structure 1, but the energy absorption performance of Structures 8 and 9 is that the energy absorption performance of Structure 1 is maintained or reduced. improving. Furthermore, in structure 8 and structure 9, the weight reduction rate of the entire frame is also large. Therefore, even in vehicle structural members such as the structures 8 and 9, it is possible to improve the energy absorption performance while reducing the weight.

1 frame 10 hollow member 10a front end 10b of hollow member rear end 11a of hollow member top surface portions 11b and 11d of hollow member side surface portions 11c of hollow member bottom portions 11e to 11h of hollow member ridge line portion 20 reinforcing member 20a reinforcing member Plate surfaces 21a to 21d of reinforcement member flange 30 crash box 40 bumper beam W _max maximum plane width of hollow member W _min minimum plane width of hollow member

Claims (5)

A metal hollow member having a tensile strength of 980 MPa or more ;
a plurality of plate-shaped reinforcing members joined to the inner surface of the hollow member and arranged at intervals along the member longitudinal direction of the hollow member so as to separate the inner space of the hollow member,
Assuming that the plane width is defined as the length of the planar portion of the hollow member in a cross section perpendicular to the member longitudinal direction of the hollow member, each reinforcing member has a plate surface extending in the member longitudinal direction of the hollow member. A structural member for a vehicle, which is oriented vertically and arranged at intervals of 0.5 times or more and 0.8 times or less of the minimum plane width of the hollow member over the entire longitudinal direction of the hollow member. 2. The structural member for a vehicle according to claim 1 , wherein said reinforcing member is a member made of FRP. 3. The structural member for a vehicle according to claim 2 , wherein said FRP is CFRP or GFRP. The reinforcing member is a member made of steel,
The structural member for a vehicle according to claim 1 , wherein the reinforcing member has a tensile strength of 440 MPa or more. The vehicle structural member according to any one of claims 1 to 4, wherein the reinforcing member has a plate thickness of 0.6 mm or less.

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