Collision energy absorption device for vehicle and method for manufacturing collision energy absorption device for vehicle

Abstract

A collision energy absorption device (10) for a vehicle comprises: an energy absorption member (20); and a shell body (30). The shell body (30) includes a lower shell (31) and an upper shell (40). The upper shell (40) includes a foot portion (41), a neck portion (42), and a head portion (43). The neck portion (42) has a double plate structure. At least the lower shell (31) and the head portion (43) are positioned on the anti-input side. At the moment of collision, the head portion (43) and the neck portion (42) having the double plate structure serve to suppress the vertical collapse of the energy absorption member (20) with respect to a load on the input side.

Description

Vehicle collision energy absorption device and method for manufacturing vehicle collision energy absorption device

[0001] The present invention relates to an improvement in a vehicle collision energy absorbing device.

[0002] [Explanation of terms] "Roll forming" is a plastic processing method in which a roll forming machine with several sets of rolls is prepared, a metal sheet is inserted into the first roll, this metal sheet is gradually bent, and the desired cross section is obtained by the last roll.

[0003] "Press forming" is a plastic processing method in which a press equipped with a punch and a die is prepared, a metal plate is placed on the die, and the punch is moved relatively into the die to obtain a drawn product. Roll forming machines are large and expensive, while presses are smaller and less expensive.

[0004] The "input side" is the side on which the external force due to the collision is first applied, and the "anti-input side" is the side on which the external force due to the collision is last affected.

[0005] [Prior Art] Electric vehicles have become increasingly popular in recent years. Many electric vehicles have a battery case located under the floor. Demand for longer driving distances has led to the adoption of large battery cases. These large battery cases extend to the side sills. Collision energy absorption devices are provided around the side sills to protect the drive battery housed in the battery case. Vehicle collision energy absorption devices with various structures have been proposed (see, for example, Patent Document 1 (FIG. 2)).

[0006] Patent Document 1 will be described with reference to the following figure. Figure 18 is a diagram illustrating the basic configuration of a conventional vehicle collision energy absorption device. As shown in Figure 18, a cross frame 102 is connected to a side sill 101, which is part of the vehicle body. A floor panel 103 is placed below this cross frame 102, and a battery case 105 is disposed below this floor panel 103.

[0007] In addition, a first collision energy absorption device 106 is attached to the underside of the side sill 101, and a second collision energy absorption device 107 is attached between the side sill 101 and the battery case 105. Since the first collision energy absorption device 106 and the second collision energy absorption device 107 are separate from the battery case 105, their plate thicknesses and shapes can be set arbitrarily.

[0008] The side sill outer 109 has upper and lower flange portions 108. The side sill inner 112 has upper and lower flange portions 111. The flange portions 108 and 111 are joined together. Due to the presence of the flange portions 108 and 111, it is unavoidable that a gap T must be provided between the first collision energy absorption device 106 and the second collision energy absorption device 107.

[0009] When subjected to the collision force indicated by the white arrow, the first collision energy absorption device 106 collapses first, absorbing the collision energy. When the collision force exceeds a certain value, the first collision energy absorption device 106 collapses and approaches the second collision energy absorption device 107, causing contact. After this contact, the second collision energy absorption device 107 collapses and further absorbs the collision energy. In this way, the battery case 105 is protected.

[0010] However, the structure disclosed in Patent Document 1 has the following drawbacks. First, the presence of the gap T prevents smooth transmission of the collision force from the first collision energy absorption device 106 to the second collision energy absorption device 107. That is, if the gap T is small, the transmission is completed in a short time, but if the gap T is large, the transmission is delayed. As a result, the collision absorption mode becomes unstable.

[0011] Next, the first collision energy absorption device 106 is fixed to the side sill outer 109 with a bolt 113. When subjected to a collision force indicated by the white arrow, the first collision energy absorption device 106 rotates around the head 114 of the bolt 113. In FIG. 18 , it rotates clockwise. As it rotates, the lower end of the first collision energy absorption device 106 hits the second collision energy absorption device 107, and the other portions of the first collision energy absorption device 106 hit the second collision energy absorption device 107 with a delay. In this way, because the first collision energy absorption device 106 and the second collision energy absorption device 107 are separated, the collision absorption mode becomes even more unstable.

[0012] Stabilization of the collision absorption mode is important, and there is a demand for a vehicle collision energy absorption device that can further stabilize the collision absorption mode.

[0013] Patent No. 7325475

[0014] An object of the present invention is to provide a vehicle collision energy absorption device that can absorb a large amount of collision energy and further stabilize the collision absorption mode.

[0015] The invention of claim 1 is a vehicle collision energy absorption device that absorbs collision energy when a collision force is applied in one direction, the vehicle collision energy absorption device comprising: an energy absorbing member that is a long material extending in a direction perpendicular to the one direction and that absorbs the collision energy in one direction; and a shell body that encases the energy absorbing member, the shell body comprising a lower shell that covers a lower part of the energy absorbing member and an upper shell that covers an upper part of the energy absorbing member, the upper shell comprising, in a cross-sectional view, a foot that extends to the lower shell and encases the energy absorbing member, a neck portion located at the base of the foot, and a head portion located above the neck portion, the neck portion having a double plate structure, and at least the lower shell and the head portion are located on the anti-input side, and in the event of a collision, the head portion and the double plate structure neck portion play a role in suppressing the energy absorbing member from falling in the vertical direction in response to a load on the input side.

[0016] The invention of claim 2 is preferably a vehicle collision energy absorption device as described in claim 1, wherein the head and foot are fixed to a mounting surface formed on a part of the vehicle body or an accessory part of the vehicle body, and in cross-sectional view, the area surrounded by the head, neck, foot and mounting surface is a closed cross-sectional portion.

[0017] The invention according to claim 3 is preferably a vehicle collision energy absorption device according to claim 1 or claim 2, wherein the energy absorbing member is a long material extending along the longitudinal axis of the vehicle, and is a corrugated plate with alternating peaks and valleys along the longitudinal axis, or a porous structure having a plurality of polygonal holes extending in the vehicle width direction.

[0018] The invention according to claim 4 is preferably a vehicle collision energy absorption device according to claim 1 or claim 2, wherein the energy absorbing member comprises a first energy absorbing member and a second energy absorbing member arranged adjacent to the first energy absorbing member, the first energy absorbing member buckling in one direction to absorb collision energy, and the second energy absorbing member extending in a direction perpendicular to the one direction to absorb collision energy by bending deformation.

[0019] A fifth aspect of the present invention is preferably the vehicle collision energy absorbing device according to the first aspect, wherein the head portion has the same width as the lower shell portion in a cross-sectional view.

[0020] The invention according to claim 6 is preferably the vehicle collision energy absorption device according to claim 4, wherein the first energy absorbing member is housed in the shell, and the second energy absorbing member is arranged outside the shell and next to the head.

[0021] A seventh aspect of the present invention is preferably the vehicle collision energy absorbing device according to the fourth aspect, wherein the shell is formed with a convex portion or a concave portion on the input side, which serves as a starting point of deformation.

[0022] An eighth aspect of the present invention is preferably the vehicle collision energy absorbing device according to the seventh aspect, wherein the convex portion or the concave portion is formed at a portion that closes a groove of the second energy absorbing member.

[0023] The invention of claim 9 is preferably the vehicle collision energy absorption device of claim 1, wherein the lower shell has a protruding portion extending toward the anti-input side, and the upper shell has a folded flange portion overlapping the protruding portion, and this folded flange portion is joined to the lower shell, or is joined to the lower shell via an inner plate that is a separate member and has a folded flange portion overlapping the protruding portion.

[0024] The invention of claim 10 is preferably the vehicle collision energy absorption device of claim 2, wherein the accessory is a battery case, and the vehicle body is equipped with the battery case that houses a battery, and the battery case has a bottom plate that supports the battery and a frame body that surrounds the battery that rests on the bottom plate, and the frame body consists of left and right side frames and cross members that extend across the front and rear ends of these side frames, and the side frames are the vehicle collision energy absorption device of claim 2.

[0025] An eleventh aspect of the present invention is preferably the vehicle collision energy absorbing device according to the second aspect, wherein the mounting surface is an outer surface of a battery case that houses a battery.

[0026] The invention according to claim 12 is preferably the vehicle collision energy absorption device according to claim 2, wherein the lower shell has a downward extension portion extending downward along the mounting surface, and the upper shell has an upward extension portion extending upward along the mounting surface.

[0027] A thirteenth aspect of the present invention is preferably the vehicle collision energy absorbing device according to the first aspect, wherein the energy absorbing member, the lower shell, and the upper shell are made of aluminum alloy plates.

[0028] The invention according to claim 14 is preferably the vehicle collision energy absorption device according to claim 1, wherein the energy absorbing member comprises a first energy absorbing member and a second energy absorbing member, and the plate thickness of the first energy absorbing member is thicker than the lower shell and the upper shell.

[0029] A fifteenth aspect of the present invention is preferably the vehicle collision energy absorbing device according to the fourteenth aspect, wherein the second energy absorbing member has a thickness thinner than that of the first energy absorbing member.

[0030] The invention according to claim 16 is preferably the vehicle collision energy absorption device according to claim 4, wherein the first energy absorbing member is divided into a plurality of members for each of the second energy absorbing members, and a stay is attached between adjacent first energy absorbing members, extending upward from the lower shell while penetrating the upper shell and being fixed directly or indirectly to the vehicle body.

[0031] The invention of claim 17 provides a method for manufacturing a vehicle collision energy absorption device, comprising: a step of manufacturing an energy absorbing member; a lower shell manufacturing step of manufacturing a dish-shaped lower shell that houses the energy absorbing member by press forming; an upper shell manufacturing step of manufacturing an upper shell that is placed over the lower shell that houses the energy absorbing member, the upper shell comprising, in cross section, a foot portion that extends to the lower shell, a neck portion located at the base of the foot portion, and a head portion located above the neck portion, by roll forming; a neck joining step of joining double plates that make up the neck portion by a laser beam or by adhesive; and a step of obtaining a vehicle collision energy absorption device by joining the upper shell to the lower shell by a laser beam or by adhesive.

[0032] In the invention according to claim 1, the shell housing the energy absorbing member is composed of a lower shell and an upper shell, and the upper shell includes a neck and a head. During a collision, the head and neck serve to prevent the energy absorbing member from collapsing vertically. Since the energy absorbing member is crushed from the input side to the anti-input side while being prevented from collapsing, the amount of collision energy absorption is increased and the collision absorption mode is stabilized. In other words, the present invention provides a vehicle collision energy absorption device that can absorb a large amount of collision energy and further stabilize the collision absorption mode.

[0033] In the invention according to claim 2, the area surrounded by the head, neck, foot, and mounting surface is a closed cross-section. The closed cross-section has greater rigidity than an open cross-section. This rigid closed cross-section maintains the position of the neck in the early stages of a collision.

[0034] In the invention according to claim 3, the energy absorbing member is a corrugated plate with alternating peaks and valleys or a porous structure having a plurality of polygonal holes. The corrugated plate or polygonal holes form a ridgeline extending in the vehicle width direction. This ridgeline buckles when subjected to a lateral load, allowing the absorption of a sufficiently large amount of collision energy.

[0035] In the invention according to claim 4, a first energy absorbing member and a second energy absorbing member are housed in the shell so as to be perpendicular and adjacent to each other. The corrugated sheet or porous structure of the first energy absorbing member buckles when a load is applied from the ridge line direction to absorb energy. The second energy absorbing member is a longitudinal member having grooves or cavities, and bends and deforms when a load is applied in the longitudinal direction to absorb energy. By combining the first energy absorbing member and the second energy absorbing member, a variety of impact absorption modes can be set, including for pole impacts.

[0036] For example, if the second energy absorbing member is placed on the input side, a point load, i.e., a local load, is applied to the second energy absorbing member when the pole hits. This local load bends the second energy absorbing member. As the second energy absorbing member bends and deforms, it converts the local load into a distributed load. This distributed load is applied to the first energy absorbing member. The distributed load is applied along the ridges of the second energy absorbing member. Since all ridges of the first energy absorbing member are crushed from the input side to the anti-input side, the energy absorption performance is improved.

[0037] Furthermore, when the first energy absorbing member is placed on the input side, the second energy absorbing member can reliably support the first energy absorbing member, which allows the first energy absorbing member to reliably buckle along the ridgeline.

[0038] In the invention according to claim 5, the head is widened to the same width as the lower shell. By widening the head, the rigidity of the head can be increased. The increased rigidity of the head can further suppress the collapse of the vehicle collision energy absorption device. In addition, the increased rigidity of the head increases the amount of collision energy absorbed by the head, improving the collision energy absorption performance of the vehicle collision energy absorption device.

[0039] In the invention according to claim 6, the first energy absorbing member is housed in the shell, while the second energy absorbing member is disposed outside the shell and next to the head. Because the second energy absorbing member is disposed next to the head, the head is necessarily small. A smaller head size allows for smaller roll-forming equipment, reducing equipment costs. Furthermore, by providing a difference in energy absorption performance between the first energy absorbing member and the second energy absorbing member, it becomes possible to accommodate a wider variety of collision patterns. Additionally, the first energy absorbing member and the second energy absorbing member begin to collapse simultaneously in parallel.

[0040] In the invention according to claim 7, the shell is provided with convex or concave portions that serve as the starting points of deformation. During a collision, the convex or concave portions are preferentially subject to plastic deformation. By providing an appropriate number of convex or concave portions in appropriate locations, crushing deformation occurs from the input side, making it possible to control the collision mode.

[0041] In the invention according to claim 8, the convex portion or concave portion is formed at a position that closes the groove of the second energy absorbing member. The groove of the second energy absorbing member and the bent portion of the convex portion or concave portion act as triggers to start absorbing the collision energy, thereby making it possible to more stably control the collision mode.

[0042] In the invention according to claim 9, the upper shell or the lower shell has a protruding portion or a folded flange, and they are stacked to form the shell body. The upper shell can be manufactured by roll forming, and the lower shell can be manufactured by press forming, which are inexpensive manufacturing methods, thereby reducing costs. In addition, roll forming can easily be used to manufacture the upper shell of a long material with a complex cross section having a head, and press forming can easily be used to manufacture the long lower shell.

[0043] In the invention according to claim 10, the function of the vehicle collision energy absorption device of the present invention is added to the side frame of a battery case, which is an accessory to the body of an electric vehicle. By using the side frame as a vehicle collision energy absorption device, the manufacturing cost of the vehicle collision energy absorption device can be reduced compared to manufacturing the side frame and the vehicle collision energy absorption device separately.

[0044] In the invention according to claim 11, the mounting surface is the side wall of the battery case. That is, a closed cross section is added that is surrounded by the side wall, head, neck, and upper shell. Because the side frame is reinforced by the vehicle collision energy absorption device, the side frame can be made thinner and smaller, and the battery case can be made lighter.

[0045] In the invention according to claim 12, the lower shell is provided with a downward extension portion extending downward, and the upper shell is provided with an upward extension portion extending upward. The downward extension portion and the upper extension portion can be directly joined to the mounting surface without a bracket. This reduces the need for mounting members such as brackets. Furthermore, because the downward extension portion and the upper extension portion are spaced apart vertically, the vehicle collision energy absorption device is stably supported on the mounting surface. Because it is stably supported, the vehicle collision energy absorption device is effectively prevented from tilting up or down during a collision.

[0046] In the invention according to claim 13, the energy absorbing member, the lower shell, and the upper shell are made of an aluminum alloy. Since aluminum alloy plates are lightweight, the weight of the energy absorbing member can be reduced. In addition, by applying an appropriate heat treatment, the strength can be improved, providing an energy absorbing member with excellent performance in absorbing collision energy.

[0047] In the invention according to claim 14, the energy absorbing member is composed of a first energy absorbing member and a second energy absorbing member, and the plate thickness of the first energy absorbing member is made thicker than the lower shell and the upper shell. Increasing the plate thickness improves the energy absorption performance of the first energy absorbing member. Furthermore, by making the lower shell and the upper shell thinner, the weight of the vehicle collision energy absorption device can be reduced. The lower shell and the upper shell are made of steel plate to provide ductility, and the energy absorbing member is made of aluminum alloy (hereinafter abbreviated as aluminum alloy) to provide rigidity, thereby increasing the variety of collision modes.

[0048] In the invention according to claim 15, the plate thickness of the second energy absorbing member is thinner than that of the first energy absorbing member. When the second energy absorbing member is arranged on the input side, the second energy absorbing member collapses first, followed by the first energy absorbing member. However, since the second energy absorbing member is thin and has low strength, it collapses quickly, so that the collapse occurs sequentially from the input side, facilitating stabilization of the collision mode.

[0049] In the invention according to claim 16, the first energy absorbing member is divided into multiple pieces in the longitudinal direction (vehicle length direction) relative to one second energy absorbing member. By dividing the first energy absorbing member, stays can be arranged between adjacent first energy absorbing members. These stays can connect the lower shell to the vehicle body or vehicle accessories. The vehicle collision energy absorption device, which extends long along the longitudinal axis of the vehicle, is attached to the vehicle body by multiple stays. The multiple stays stabilize the vehicle collision energy absorption device.

[0050] A method for manufacturing a vehicle collision energy absorption device according to claim 17 includes a process for manufacturing an energy absorbing member, a process for manufacturing a lower shell by press molding, a process for manufacturing an upper shell by roll forming, a process for joining the neck using a laser beam or adhesive, and a process for joining other parts of the neck using a laser beam or adhesive. Vehicle collision energy absorption devices can be manufactured at low cost using general-purpose techniques such as press molding, roll forming, and laser welding (or adhesive). The energy absorbing member can be sandwiched between the lower shell and the upper shell to form an integrated structure, making manufacturing easier.

[0051] 13A and 13B are cross-sectional views of a vehicle collision energy absorption device according to the present invention; FIG. 14A is a perspective view of an energy absorbing member, which is one of the main elements of the vehicle collision energy absorption device; (a) and (b) are diagrams illustrating the operation of the vehicle collision energy absorption device; (a) to (c) are diagrams illustrating advantages of the vehicle collision energy absorption device according to the present invention; FIG. 14B is a perspective view showing a modified example of the energy absorbing member; (a) is a cross-sectional view of a vehicle collision energy absorption device including a first energy absorbing member and a second energy absorbing member; (a) to (c) are diagrams illustrating the operation of the first energy absorbing member and the second energy absorbing member; FIG. 14B is another cross-sectional view of a vehicle collision energy absorption device including a first energy absorbing member and a second energy absorbing member; (a) and (b) are diagrams illustrating a modified example of the vehicle collision energy absorption device; (a) to (c) are diagrams illustrating a modified example of the vehicle collision energy absorption device; FIG. 14B is an exploded perspective view of a battery case; and (b) is a cross-sectional view taken along line 14-14 of FIG. 13A. 1A is a diagram illustrating a modified example of a vehicle collision energy absorption device, and FIG. 1B is a view taken along the arrows bb in FIG. 1A. A diagram illustrating a modified example of a vehicle collision energy absorption device. A flow chart illustrating a manufacturing method of a vehicle collision energy absorption device. A diagram illustrating the basic configuration of a conventional vehicle collision energy absorption device.

[0052] An embodiment of the present invention will be described below with reference to the accompanying drawings.

[0053] Hereinafter, the configuration of the vehicle collision energy absorption device 10 attached to a vehicle will be described with reference to FIGS. 1, 2, and 5, and the operation of the vehicle collision energy absorption device 10 when a collision force is applied to the vehicle will be described with reference to FIGS. 3(a), 3(b), and 4(a) to 4(c).

[0054] 1, a vehicle collision energy absorption device 10 is attached to a vehicle body, for example, in a form housed in a side sill 11. The vehicle collision energy absorption device 10 mainly includes an energy absorbing member 20 and a shell 30 that encases the energy absorbing member 20.

[0055] [Shell] The shell 30 is a hollow body whose main elements are a lower shell 31 that covers the lower part of the energy absorbing member 20 and an upper shell 40 that covers the upper part of the energy absorbing member 20. Details of the energy absorbing member 20 will be described with reference to FIG. 2 .

[0056] [Lower Shell] The lower shell 31 is a dish-shaped tray. The dish shape has a cross section that is approximately Z-shaped, L-shaped, U-shaped, etc. The lower shell 31 is manufactured by press molding from a single metal plate (aluminum alloy or steel plate).

[0057] [Upper Shell] The upper shell 40 comprises a pair of foot portions 41 that extend and widen to the lower shell 31, a neck portion 42 located at the base of the foot portions 41, and a head portion 43 located above the neck portion 42. The upper shell 40 has an octopus shape in cross section. Although the upper shell 40 has a somewhat complex shape, it is manufactured by roll forming from a single metal plate.

[0058] [Neck] The neck 42 is a double-plate structure in which two metal plates are joined together with a welded metal 44 by laser welding or the like. Because it is a double-plate structure, the neck 42 has sufficient strength and rigidity, and has the advantage that it is less likely to lose its shape between the neck 42 and the head 43 even when subjected to an external force.

[0059] [Part of Vehicle Body or Vehicle Body Accessory Part] The part of the vehicle body is, for example, a side sill 11. The side sill 11 is a hollow body formed by joining together a side sill outer 12 and a side sill inner 13. In this example, the lower shell 31, the foot 41, and the head 43 are fixed to the side sill inner 13 by welding via an inner plate 14 of appropriate thickness and size.

[0060] The inner plate 14 may be omitted, and the lower shell 31, the foot portion 41, and the head portion 43 may be directly fixed to the side sill inner 13 by welding. That is, at least the lower shell 31 and the head portion 43 are fixed to the vehicle body (e.g., the side sill inner 13) directly or indirectly via the inner plate 14.

[0061] [Closed Cross-Section Portion] One surface of the inner plate 14 serves as the mounting surface 15 formed on a part of the vehicle body or an accessory to the vehicle body. Alternatively, the inner surface of the side sill inner 13 serves as the mounting surface 15 formed on a part of the vehicle body or an accessory to the vehicle body. The lower shell 31, the foot 41, and the head 43 are fixed to this mounting surface 15. At this time, the area surrounded by the head 43, the neck 42, the foot 41, and the mounting surface 15 serves as the closed cross-section portion 45. Compared to an open cross-section, the closed cross-section portion 45 has greater strength and rigidity. The presence of this closed cross-section portion 45 with greater strength and rigidity maintains the position of the neck 42 during a collision.

[0062] 2, the energy absorbing member 20 is an elongated member extending along the vehicle's longitudinal axis 21. Preferably, the elongated member is a corrugated plate having alternating peaks 22 and valleys 23 arranged along the vehicle's longitudinal axis 21.

[0063] The corrugated plate has ridges that are perpendicular to the longitudinal axis 21 of the vehicle. In the event of a side collision, such as a collision with a pole, the ridges buckle to absorb energy. The energy absorbing member 20 can absorb a sufficiently large amount of collision energy.

[0064] [Operation] In the case of a pole collision in Figure 3(a), assume that the pole 16 collides with the vehicle collision energy absorption device 10 as indicated by the white arrow. As shown in Figure 3(b), the ridges of the energy absorbing member 20 primarily buckle and undergo plastic deformation. At this time, the lower shell 31 and the upper shell 40 stabilize the plastic deformation. As a result, the energy absorbing member 20 absorbs the collision energy.

[0065] As shown in Figure 3(a), the head 43 is made of a relatively thin metal plate, but has large length and width dimensions, so it has high strength and rigidity as indicated by the section modulus and moment of inertia. In addition, the neck 42 has a double-plate structure, so it has a certain level of strength.

[0066] 4(a) to 4(c) , let us consider a case where the upper shell 40 does not have a neck 42, but is composed of a foot 41 and a U-shaped head 43, as shown in FIG.

[0067] In an actual collision, the white arrow is often displaced up or down or slightly tilted relative to the horizontal. For example, due to the tilt, a component force of the collision load is applied upward (or downward) to the vehicle collision energy absorption device 10. Then, as shown in Figure 4(b), the U-shaped head 43 easily deforms, and as a result, the vehicle collision energy absorption device 10 falls upward (or downward).

[0068] 4(c), in the embodiment of the present invention, collapse is suppressed by the supporting action between the head portion 43 and the neck portion 42, particularly the supporting action of the neck portion 42. As a result, collapse is suppressed, and the ridges of the vehicle collision energy absorption device 10 buckle and collapse (plastically deform) along their entire length, absorbing the collision energy.

[0069] That is, in FIG. 3( a ), the presence of the head portion 43 and neck portion 42 prevents the foot portion 41 and the lower shell 31 accommodating the energy absorbing member 20 from tipping over.

[0070] As a result, as shown in FIG. 3B, the vehicle collision energy absorption device 10 does not collapse vertically (even if it does collapse, it is sufficiently suppressed) and the energy absorbing member 20 undergoes plastic deformation.

[0071] At this time, the presence of the closed cross-sectional portion 45 contributes to improving the rigidity of the vehicle collision energy absorption device 10 and plays a role in promoting stable plastic deformation of the vehicle collision energy absorption device 10 .

[0072] [Modification of Energy Absorbing Member] As shown in Fig. 5, the energy absorbing member 20 may be a porous structure or a honeycomb structure having a plurality of polygonal holes 25 with polygonal cross sections including rectangular cross sections. In either case, the holes form ridges at the corners. That is, this energy absorbing member 20 is an elongated member extending along the longitudinal axis 21 of the vehicle, and has a plurality of polygonal holes 25 extending in a direction perpendicular to the longitudinal axis 21 of the vehicle (vehicle width direction).

[0073] Because it is a porous structure or a honeycomb structure, it is sufficiently lightweight. Despite its light weight, it has ridges in the direction perpendicular to the longitudinal axis 21 of the vehicle (the vehicle width direction), and can buckle to absorb a sufficiently large amount of collision energy.

[0074] The following describes modified examples of the vehicle collision energy absorbing device 10. In the following description, the same components as those in Fig. 1 will be designated by the same reference numerals as in Fig. 1, and detailed description thereof will be omitted.

[0075] [First Modification of Vehicle Collision Energy Absorption Device] As shown in Fig. 6, the energy absorbing member 20 comprises a first energy absorbing member 26 and a second energy absorbing member 27 arranged in contact with or adjacent to the first energy absorbing member 26. The second energy absorbing member 27 is arranged on the input side (outer side in the vehicle width direction). The first energy absorbing member 26 may be the one illustrated in Fig. 2 or Fig. 5.

[0076] [Second Energy Absorbing Member] As shown in FIG. 7, the second energy absorbing member 27 is an elongated member having a groove 28 with an open cross section (or a cavity with a closed cross section) extending along the longitudinal axis 21 of the vehicle.

[0077] [Operation of Modified Example 1] As shown in FIG. 8(a), the pole 16 collides with the vehicle collision energy absorption device 10 as indicated by the white arrow.

[0078] Figure 8(b) is a view taken along the arrows bb in Figure 8(a). The pole 16 first collides with the second energy absorbing member 27 at a point. The second energy absorbing member 27 bends and deforms, dispersing the impact force in a tree-like pattern along the longitudinal axis 21 of the vehicle. The dispersed impact force is applied to the ridge of the first energy absorbing member 26.

[0079] 8(c), the second energy absorbing member 27 is crushed first. The first energy absorbing member 26 comes into contact with this second energy absorbing member 27, and the first energy absorbing member 26 begins to crush. By creating a difference in energy absorption performance between the buckling deformation of the ridgeline of the first energy absorbing member 26 and the bending deformation of the second energy absorbing member 27, it becomes possible to respond to a variety of collision patterns.

[0080] 9, the energy absorbing member 20 comprises a first energy absorbing member 26 and a second energy absorbing member 27 arranged in contact with or adjacent to the first energy absorbing member 26. The second energy absorbing member 27 is arranged on the non-input side (the mounting surface 15 side).

[0081] 8(b) , the effect of dispersing the impact force cannot be obtained, but the second energy absorbing member 27 can reliably support the first energy absorbing member 26 and promote buckling of the ridges of the first energy absorbing member 26. If the second energy absorbing member 27 has a groove 28, the opening of the groove 28 is closed by the lower shell 31 (or upper shell 40). By closing it, a closed cross section is formed.

[0082] 10(a), the width (width in the vehicle width direction) of the head 43 may be increased so that the neck 42 is located near the center of the width of the head 43. Furthermore, as shown in FIG. 10(b), the width of the head 43 may be increased significantly so that it has the same width as the lower shell 31.

[0083] Increasing the width of the head portion 43 increases the strength and rigidity of the head portion 43. The increased strength and rigidity of the head portion 43 further suppresses collapse of the energy absorbing member 20. In addition, the increased rigidity of the head portion 43 increases the amount of collision energy absorbed by the head portion 43, improving the collision energy absorption performance of the vehicle collision energy absorption device 10.

[0084] [Variation 4 of Vehicle Collision Energy Absorption Device] As shown in Figure 11, the first energy absorbing member 26 may be housed in the shell 30, and the second energy absorbing member 27 may be arranged outside the shell 30 and next to the head 43.

[0085] In the configuration of Fig. 6, the first energy absorbing member 26 begins to collapse after the second energy absorbing member 27 has collapsed. In contrast, in the configuration of Fig. 11, the first energy absorbing member 26 and the second energy absorbing member 27 begin to collapse simultaneously. Because the energy absorption performance of the first energy absorbing member 26 and the second energy absorbing member 27 differs, it is possible to respond to a wider variety of collision patterns.

[0086] [Variation 5 of Vehicle Collision Energy Absorption Device] The vehicle collision energy absorption device 10 can be applied to the side frame of a battery case, which is an accessory to the vehicle body. In this case, as shown in Fig. 12(a), convex portions 46 (or concave portions) that serve as deformation starting points may be provided at any location on the shell 30. During a collision, the convex portions 46 are preferentially subject to plastic deformation. By providing an appropriate number of convex portions 46 at appropriate locations, it is possible to control the collision mode.

[0087] 12(b), the convex portion 46 (or the concave portion) may be provided at a position that closes the groove 28 of the second energy absorbing member 27. The groove 28 of the second energy absorbing member 27 and the bent portion of the convex portion 46 (or the concave portion) act as a trigger to start absorbing the collision energy, thereby making it possible to more stably control the collision mode.

[0088] 12( a), a protruding portion 32 extending toward the anti-input side is provided on the lower shell 31. A folded flange portion 47 overlapping the protruding portion 32 may be provided on the upper shell 40, and the folded flange portion 47 may be joined to the protruding portion 32 of the lower shell 31.

[0089] 12( c), a protruding portion 32 extending toward the side opposite to the input side is provided on the lower shell 31. An inner plate 14 is prepared as a separate member having a folded flange portion 47 that overlaps the protruding portion 32. The folded flange portion 47 may then be joined to the protruding portion 32 of the lower shell 31.

[0090] The upper shell 40 is manufactured by roll forming. Roll forming makes it possible to manufacture even complex cross sections. The lower shell 31 is manufactured by press forming. Press forming reduces manufacturing costs.

[0091] [Eighth Modification of Vehicle Collision Energy Absorption Device] Fig. 13 shows a battery case 50 mounted on a vehicle body. As shown in Fig. 13, the battery case 50 includes a bottom plate 52 that supports a battery 51, a frame 53 that surrounds the battery 51 placed on the bottom plate 52, a lid 54 that closes the upper opening of the frame 53, and a protection plate 55 that protects a cooler disposed below the bottom plate 52.

[0092] The frame 53 is made up of left and right side frames 56, cross members 57 respectively extending across the front and rear ends of these side frames 56, and sub-cross members 58 extending across the left and right side frames 56.

[0093] Figure 14 is a cross-sectional view taken along line 14-14 in Figure 13. As shown in Figure 14, the side frames 56 of the battery case 50 are the vehicle collision energy absorption device 10 of the present invention. In other words, the side frames 56 are also used as the vehicle collision energy absorption device 10.

[0094] Compared to manufacturing the side frame 56 and the vehicle collision energy absorption device 10 separately, by using the side frame 56 of the battery case 50 as both the vehicle collision energy absorption device 10, the manufacturing cost of the vehicle collision energy absorption device 10 can be reduced.

[0095] 15( a), the vehicle collision energy absorption device 10 may be later attached to the side frame 56 of the battery case 50. In other words, the attachment surface 15 of the vehicle collision energy absorption device 10 may be the side wall of the battery case 50 or the outer surface of the side frame 56.

[0096] Since the side frame 56 is reinforced by the vehicle collision energy absorption device 10, the side frame 56 can be made thinner and smaller, and the weight of the battery case 50 can be reduced.

[0097] [Modification 10 of Vehicle Collision Energy Absorption Device] As shown in FIG. 16 , the lower shell 31 may be provided with a downward extension 33 extending downward along the mounting surface 15, and the upper shell 40 may be provided with an upward extension 48 extending upward along the mounting surface 15.

[0098] The lower extension 33 and the upper extension 48 are joined to the mounting surface 15. Because the lower extension 33 and the upper extension 48 are spaced apart vertically, the vehicle collision energy absorption device 10 is stably supported on the mounting surface 15. Because the vehicle collision energy absorption device 10 is stably supported, it is effectively prevented from tilting up or down during a collision.

[0099] [Modification 11 of Vehicle Collision Energy Absorption Device] In Fig. 1 , the energy absorbing member 20, the lower shell 31, and the upper shell 40 are preferably made of aluminum alloy plates. Because aluminum alloy plates are lightweight, the weight of the energy absorbing member 20 can be reduced. In addition, by subjecting the aluminum alloy plates to an appropriate heat treatment, the strength can be improved. That is, by subjecting the aluminum alloy plates to heat treatment, the energy absorbing member 20 can be provided with excellent performance in absorbing collision energy.

[0100] 6 , the energy absorbing member 20 is made up of a first energy absorbing member 26 and a second energy absorbing member 27. The plate thickness of the first energy absorbing member 26 is made thicker than the lower shell 31 and the upper shell 40.

[0101] Increasing the plate thickness improves the energy absorption performance of the first energy absorbing member 26. In addition to using an aluminum alloy plate for the first energy absorbing member 26, the lower shell 31 and the upper shell 40 can be made of steel plate. Because steel plate has ductility, it can stabilize the plastic deformation of the energy absorbing member.

[0102] [Variation 13 of Vehicle Collision Energy Absorption Device] In Figure 6, the plate thickness of the second energy absorbing member 27 is thinner than that of the first energy absorbing member 26. If the second energy absorbing member 27 is arranged on the input side, the second energy absorbing member 27 will crush first, followed by the first energy absorbing member 26. Because the second energy absorbing member 27 is thin, it has low strength and will crush quickly. The energy absorbing members 20 will crush sequentially from the input side. As a result, the collision mode of the energy absorbing member 20 will be stabilized.

[0103] [Modification 14 of the vehicle collision energy absorption device] Fig. 15(b) is a view (partially omitted) taken along the line b-b in Fig. 15(a). As shown in Fig. 15(b), the first energy absorbing member 26 may be divided into a plurality of members for one second energy absorbing member 27.

[0104] By dividing the first energy absorbing members 26, a gap is created between adjacent first energy absorbing members 26, and a stay 59 can be placed in this gap. As shown in Fig. 15(a) , the stay 59 extends upward from the lower shell 31 while penetrating the upper shell 40, and is fixed to, for example, the side sill 11. The side sill 11 may be replaced by a part of the vehicle body or a vehicle body accessory.

[0105] The vehicle collision energy absorption device 10, which extends long along the longitudinal axis of the vehicle, is attached to the vehicle body by a plurality of stays 59. The vehicle collision energy absorption device 10 is stabilized by the plurality of stays 59.

[0106] [Method for manufacturing a vehicle collision energy absorption device] As shown in Figure 17, for example, in step (hereinafter referred to as ST) 01, an energy absorbing member is manufactured, in ST02 a lower shell is manufactured, the energy absorbing member is joined to the lower shell, in ST03 an upper shell is manufactured, in ST04 a neck is joined, and in ST05 the upper shell is joined to the lower shell and the energy absorbing member, thereby manufacturing a vehicle collision energy absorption device. Note that the shell body is divided into upper and lower parts by the lower shell and the upper shell. This makes it easy to accommodate the energy absorbing member in the shell body. The energy absorbing member can be easily joined to the shell body. The order of ST01 to ST03 may be reversed or may be performed simultaneously in parallel.

[0107] [Energy Absorption Member Manufacturing Process] For example, the energy absorption member 20 shown in FIG. 2 is manufactured by bending a single aluminum alloy plate or steel plate.

[0108] [Lower Shell Manufacturing Process] A single aluminum alloy plate or steel plate is press-formed to manufacture the dish-shaped lower shell 31 shown in Fig. 1. Press forming allows the lower shell 31 to be manufactured inexpensively.

[0109] [Upper shell manufacturing process] The upper shell 40 shown in Fig. 1 is manufactured by roll forming a single aluminum alloy plate or steel plate. By roll forming, it is possible to form a single-stroke shape and a complex shape.

[0110] [Neck Joining Step] The double plates constituting the neck 42 shown in Fig. 1 are joined by a laser beam, or by adhesive, or by spot welding or rivet joining.

[0111] [Joining Process] The energy absorbing member 20 is set at a desired position on the lower shell 31. They are joined using a laser beam (welding) or an adhesive. The lower shell 31 has an open top surface. This allows spot or linear welding to be easily performed, resulting in sufficiently strong joint strength. Furthermore, because the lower shell 31 has an open top surface, multiple energy absorbing members can be easily set on the lower shell 31. Furthermore, because the lower shell 31 has an open top surface, it is possible, for example, to set the energy absorbing member 20 on the lower shell 31 with a space left on the input side. Thereafter, the upper shell 40 is joined to the lower shell 31 to form the shell body 30. This facilitates integration of the shell body 30 and the energy absorbing member 20.

[0112] According to the method of the present invention, the vehicle collision energy absorption device 10 can be manufactured at low cost using general-purpose techniques such as press molding, die forming, and laser welding (or bonding).

[0113] The present invention is suitable for a vehicle collision energy absorbing device attached to a vehicle body.

[0114] 10...vehicle collision energy absorption device, 14...inner plate, 15...mounting surface, 20...energy absorbing member, 21...longitudinal axis (longitudinal axis of vehicle), 22...ridge, 23...valley, 25...polygonal hole, 26...first energy absorbing member, 27...second energy absorbing member, 28...groove, 30...shell, 31...lower shell, 32...projection portion, 33...downward extension portion, 40...upper shell, 41...foot portion, 42...neck portion, 43...head portion, 45...closed cross section portion, 46...convex portion, 48...upper extension portion, 50...battery case, 51...battery, 52...bottom plate, 53...frame body, 56...side frame, 57...cross member, 59...stay.

Claims

1. A vehicle collision energy absorption device that is attached to a vehicle body and absorbs collision energy when a collision force is applied to the vehicle, said vehicle collision energy absorption device comprising: an energy absorbing member that is a long material extending in a direction perpendicular to one direction and absorbs the collision energy in one direction; and a shell body that encases the energy absorbing member, said shell body comprising a lower shell that covers a lower part of the energy absorbing member and an upper shell that covers an upper part of the energy absorbing member, said upper shell comprising: a foot that extends to the lower shell and encases the energy absorbing member, a neck portion located at the base of the foot, and a head portion located on top of the neck portion, said neck portion having a double plate structure with at least the lower shell and the head portion located on the anti-input side, and in the event of a collision, said head portion and said double plate structured neck portion play a role in suppressing the vertical collapse of the energy absorbing member in response to a load on the input side.

2. A vehicle collision energy absorption device as described in claim 1, wherein the head and foot are fixed to a mounting surface formed on a part of the vehicle body or an accessory of the vehicle body, and in cross-sectional view, the area surrounded by the head, neck, foot and mounting surface is a closed cross-sectional portion.

3. A vehicle collision energy absorption device as claimed in claim 1 or 2, wherein the energy absorbing member is a long material extending along the longitudinal axis of the vehicle and is a corrugated plate having alternating peaks and valleys arranged along the longitudinal axis, or a porous structure having a plurality of polygonal holes extending in the vehicle width direction.

4. A vehicle collision energy absorption device as claimed in claim 1 or 2, wherein the energy absorbing member comprises a first energy absorbing member and a second energy absorbing member arranged adjacent to the first energy absorbing member, the first energy absorbing member buckles in one direction to absorb collision energy, and the second energy absorbing member extends in a direction perpendicular to the one direction and absorbs collision energy by bending deformation.

5. A vehicle collision energy absorbing device according to claim 1, wherein the head portion has the same width as the lower shell in a cross-sectional view.

6. A vehicle collision energy absorbing device according to claim 4, wherein the first energy absorbing member is housed in the shell, and the second energy absorbing member is disposed outside the shell and to the side of the head.

7. A vehicle collision energy absorbing device according to claim 4, wherein the shell has a convex or concave portion formed on the input side, the convex or concave portion being a starting point of deformation.

8. A vehicle collision energy absorbing device as set forth in claim 7, wherein the convex portion or the concave portion is formed in a portion that closes a groove of the second energy absorbing member.

9. A vehicle collision energy absorption device as described in claim 1, wherein the lower shell has a protruding portion extending toward the anti-input side, and the upper shell has a folded flange portion overlapping the protruding portion, and this folded flange portion is joined to the lower shell, or is joined to the lower shell via an inner plate that is a separate member and has a folded flange portion overlapping the protruding portion.

10. A vehicle collision energy absorption device as defined in claim 2, wherein the accessory part is a battery case, the vehicle body is provided with the battery case for housing a battery, the battery case is provided with a bottom plate for supporting the battery and a frame body for surrounding the battery placed on the bottom plate, the frame body being made up of left and right side frames and cross members respectively extending between the front and rear ends of these side frames, and the side frames are the vehicle collision energy absorption device as defined in claim 2.

11. A vehicle collision energy absorbing device according to claim 2, wherein the mounting surface is an outer surface of a battery case that houses a battery.

12. A vehicle collision energy absorption device as described in claim 2, wherein the lower shell has a downward extension portion extending downward along the mounting surface, and the upper shell has an upward extension portion extending upward along the mounting surface.

13. A vehicle collision energy absorbing device according to claim 1, wherein the energy absorbing member, the lower shell and the upper shell are made of aluminum alloy plates.

14. A vehicle collision energy absorption device as described in claim 1, wherein the energy absorbing member comprises a first energy absorbing member and a second energy absorbing member, and the plate thickness of the first energy absorbing member is thicker than the lower shell and the upper shell.

15. A vehicle collision energy absorbing device according to claim 14, wherein the plate thickness of the second energy absorbing member is thinner than that of the first energy absorbing member.

16. A vehicle collision energy absorption device as described in claim 4, wherein the first energy absorbing member is divided into a plurality of members for each of the second energy absorbing members, and a stay is attached between adjacent first energy absorbing members, extending upward from the lower shell while penetrating the upper shell, and fixed directly or indirectly to the vehicle body.

17. A method for manufacturing a vehicle collision energy absorption device comprising the steps of: a step of manufacturing an energy absorbing member; a lower shell manufacturing step of manufacturing a dish-shaped lower shell by press molding that houses the energy absorbing member; an upper shell manufacturing step of manufacturing an upper shell by roll forming to be placed over the lower shell in which the energy absorbing member is housed, the upper shell comprising, in cross-section, a foot extending to the lower shell, a neck located at the base of the foot, and a head located above the neck; a neck joining step of joining a double plate that constitutes the neck by a laser beam or by adhesive; and a step of obtaining a vehicle collision energy absorption device by joining the upper shell to the lower shell by a laser beam or by adhesive.

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