TECHNICAL FIELD OF THE INVENTION

The present invention relates to a hollow member.

RELATED ART

As a method of forming a structure such as a vehicle, a railway vehicle, an aircraft, or a building, there is a method of forming a structure using a frame corresponding to a skeleton and other structural members (such as a sheath). Such a frame typically requires high-strengthening and a reduction in weight from the viewpoint of improving the strength of the structure and suppressing costs. For example, regarding vehicles, high-strengthening and thinning of steel sheets forming a frame have proceeded from the viewpoint of maintaining or improving collision safety performance and improving fuel efficiency.

In addition, in order to suppress deformation of the frame in a collision of a vehicle or the like, the inside of the frame may be filled with a filling member formed of a foamed resin material or the like. For example, Patent Document 1 below discloses a technique in which a filling member is disposed inside a frame with no gap.

PRIOR ART DOCUMENT

Patent Document

[Patent Document 1] Japanese Unexamined Patent Application, First Publication No. 2002-18868

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

When a load is applied to a frame as in a collision of a vehicle, the frame is deformed. At this time, deformation occurs in the cross section of the frame. This deformation is called cross-sectional deformation. When the load applied to the frame exceeds a predetermined value, buckling occurs in the frame, and the load bearing performance of the frame is significantly reduced. Occurrence of buckling means bending. In this case, there is a possibility that the amount of absorbed energy postulated for the frame may not be secured.

It is considered that the cross-sectional deformation of the frame is suppressed by filling the inner space of the frame with a filling member. However, when the filling member is filled unnecessarily as in the technique described in Patent Document 1, the weight of the frame is increased in return for the improvement in the amount of absorbed energy.

For this reason, the present inventors considered that it is useful to further improve the mass efficiency for improving the amount of absorbed energy by the filling member and to suppress the out-of-plane deformation that causes a reduction in the amount of absorbed energy of the frame. However, no effective disposition of the filling member has been hitherto examined for suppressing out-of-plane deformation and improving the amount of absorbed energy of the frame.

The present invention has been made in view of the above problems. An object of the present invention is to provide a novel and improved hollow member that realizes energy absorption at the time of load input with high mass efficiency.

Means for Solving the Problem

In order to solve the above-described problems, according to the present invention, there is provided a hollow member including: a hollow metal member having a bending induction portion in a portion thereof in a longitudinal direction; and a resin material made of a resin having a Young's modulus of 20 MPa or more and disposed in the bending induction portion in close contact with the metal member.

The metal member may include a bottom wall part, a pair of side wall parts standing from both ends of the bottom wall part, and a top wall part facing the bottom wall part, and a closed cross section may be formed by the bottom wall part, the pair of side wall parts, and the top wall part.

The resin material may be disposed in close contact with an inner surface of at least one of the bottom wall part and the top wall part.

The resin material may be disposed in close contact with an inner surface of at least one of the pair of side wall parts.

A second metal sheet may be disposed on an inside of the metal member and joins to a first metal sheet forming the metal member.

The resin material may be disposed in close contact with the second metal sheet.

The first metal sheet forming the metal member may have a hole, the resin material may be made of a foamed resin, and the resin material may pass through the hole and be disposed in close contact with both an outer surface and an inner surface of the first metal sheet.

A hole edge end of the hole may be located inward of the metal member from the first metal sheet forming the metal member.

The hole may be a burring hole in which the hole edge end of the hole protrudes from an outside to the inside of the first metal sheet forming the metal member.

The hole may be provided with a recess portion recessed inward of the metal member from the first metal sheet forming the metal member, and the hole may be provided in an inner portion of the recess portion.

The bending induction portion may be a portion where a full plastic moment of the metal member changes in the longitudinal direction.

The bending induction portion may be a portion in which a radius of curvature of a locus of a center of mass along the longitudinal direction formed by the center of mass of a cross sections of the metal member is 260 mm or less.

The bending induction portion may be a sheet thickness changing portion.

The bending induction portion may be a portion provided with a recessed part.

The bending induction portion may be a portion provided with a protrusion.

The bending induction portion may be a portion provided with a hole.

The resin material may be disposed so as to cover the bending induction portion and peripheral portions of the bending induction portion on both sides in the longitudinal direction.

The resin material may be disposed so as to cover the bending induction portion and the peripheral portions of the bending induction portion on both sides in the longitudinal direction within a range in which a distance from the bending induction portion to an end portion of the resin material in the longitudinal direction is ½ or less of a cross-sectional height of the metal member.

In a cross section of the metal member, the resin material may be disposed on a side where the bending induction portion is present with respect to a boundary that halves the cross section in a height direction of the cross section defined by a direction from a center of mass of the cross section toward the bending induction portion.

The resin material may be disposed in a portion of the bending induction portion and is not disposed in another portion of the bending induction portion.

According to the above configuration, while bending deformation is induced by the bending induction portion at the time of load input, out-of-plane deformation that occurs in the bending induction portion when the bending deformation occurs can be suppressed by the resin material disposed in the bending induction portion. Accordingly, since the out-of-plane deformation of the hollow member at the time of load input is suppressed, the load bearing performance exhibited by the cross section of the hollow member can be maintained in a level postulated in a design stage. Therefore, the amount of absorbed energy at the time of load input can be improved. Moreover, since the place where out-of-plane deformation has to be suppressed is limited to the bending induction portion or the periphery thereof, the amount of absorbed energy at the time of load input can be improved with high mass efficiency.

Effects of the Invention

As described above, according to the present invention, energy absorption at the time of load input can be realized with high mass efficiency.

