JP6184130B2 - Cylindrical structure for automobile frame structure and automobile frame structure - Google Patents

Description

  The present invention relates to a tubular structure and an automobile frame structure using the tubular structure.

  For example, as a cylindrical structure that absorbs energy generated when an automobile collides, a front side member of the automobile, a crash box disposed in front of the front side member, or the like is used. Such a cylindrical structure for energy absorption absorbs energy by crushing when energy is loaded.

  As such a cylindrical structure, for example, a prismatic member having a bead provided at a constant distance is known (Patent Documents 1, 2, etc.). For example, in the cylindrical structures described in Patent Documents 1 and 2, annular beads formed over the entire circumference of the rectangular tubular member are provided at regular intervals.

  In particular, in the cylindrical structure described in Patent Document 1, one of the two planar portions adjacent to the circumferential direction of the rectangular tubular member is formed in a concave shape on the one hand, and on the other side in a convex shape. The circumference of the cross section and the circumference of the cross section where no bead is provided are substantially the same. Moreover, in the cylindrical structure described in Patent Document 2, the bead is formed in a convex shape in two planar portions adjacent to the circumferential direction of the rectangular tubular member, and in the corner portion between these two planar portions. It is formed in a concave shape. Thus, by providing a bead on the surface of the rectangular tube-shaped member, when energy is loaded on the rectangular tube-shaped member, the bead is crushed from the bead as a starting point. For this reason, it is supposed that crushing of a rectangular tube-shaped member can be controlled, and as a result, energy can be effectively absorbed when energy is loaded on the rectangular tube-shaped member.

Further, a structure using origami engineering is known as a structure that can fold a structure very small in the load direction with a small load (for example, Patent Document 3 ). In particular, Patent Document 3 discloses a cylindrical structure including a plurality of cylindrical partial structures arranged in succession, and in this cylindrical structure, each partial structure is the same hexagon. It has a first end portion and a second end portion having a shape, and a side portion extending between the first end portion and the second end portion. In addition, in this cylindrical structure, the first end portion is twisted at a predetermined angle with respect to the second end portion, and between each side of the first end portion and each side of the second end portion corresponding to this side. A valley fold line is formed on a diagonal line in each of the partial side portions provided in FIG. According to Patent Document 3, by configuring the cylindrical structure in this way, the amount of energy absorption can be increased and the reaction force can be increased.

JP 2008-94309 A JP 2008-1005009 A JP 2011-104612 A

  By the way, when a car collides, it does not necessarily collide from the front, and may collide diagonally. Therefore, when the cylindrical structure as described above is used as, for example, a front side member of an automobile or a crash box disposed in front of the front side member, the collision load is not necessarily input in the axial direction of the cylindrical structure. However, it may be input from a direction inclined with respect to the axial direction.

  As described above, when a load is input from a direction inclined with respect to the axial direction, the cylindrical structures described in Patent Documents 1 to 4 tend to bend at the root portion. This is shown in FIG. In the illustrated example, the tubular structure 100 is used as a crush box disposed in front of the front side member 101. FIG. 1A shows the cylindrical structure 100 before the load is input, and FIG. 1B shows the cylindrical structure 100 after the load is input. The cylindrical structure 100 is fixed in front of the front side member 101, and a collision load in the direction indicated by the arrow X in FIG. When such a collision load is input, the cylindrical structure 100 bends at a location indicated by a point Y as shown in FIG.

  If the tubular structure 100 is bent in this manner, the tubular structure 100 can no longer absorb sufficient energy. As a result, when a load is input from a direction inclined with respect to the tubular structure, the amount of energy absorbed by the tubular structure 100 is small. For this reason, there is a need for a cylindrical structure having high robustness, which is a property of being deformed and crushed in the same way regardless of the load applied from any direction.

  In addition, when the cylindrical structure 100 is used as a crash box, if the reaction force fluctuation during the crushing of the cylindrical structure 100 increases, the front side member may be unexpectedly deformed or may absorb sufficient energy. It becomes impossible to do. That is, when the maximum value of the reaction force at the time of crushing of the cylindrical structure 100 becomes large, a large load is applied to the front side member coupled to the crash box, which causes unexpected deformation of the front side member. It will be. In addition, since the energy absorbed by the cylindrical structure 100 is proportional to the magnitude of the reaction force, if the minimum value of the reaction force when the cylindrical structure 100 is crushed is small, the energy is absorbed by the cylindrical structure 100. Energy is also reduced.

  Therefore, in view of the above problems, an object of the present invention is to provide a cylindrical structure having high robustness while suppressing reaction force fluctuation during crushing.

  The present inventor has studied various structures of the cylindrical structure regarding the reaction force fluctuation and robustness at the time of crushing the cylindrical structure, and among these, the cylindrical structure has the following structure. We also examined things. That is, it comprises a plurality of cylindrical partial structures arranged in succession, and each partial structure has the same hexagonal first end and second end, and these first end and second A cylindrical structure having a side portion extending between the first end portion and the second end portion, the first end portion being twisted by a predetermined angle, and each side of the first end portion and this side On each side portion of the second end corresponding to each side, a valley fold line is formed on a diagonal line, and hexagonal first end portions are formed on both sides of the side portion. A cylindrical structure in which a mountain fold line connecting the corner portion and the corner portion of the hexagonal second end corresponding to the corner portion was examined.

  As a result, the angle between the mountain fold line on each side portion and the plane on which the first end portion is located and the plane on which the two end portions are located are substantially the same at θ, and the cylindrical structure is configured. By setting the angle θ in the partial structure located at one end of the tubular structure among the plurality of partial structures to an appropriate value, the tubular structure can be crushed compared to the conventional tubular structure. It has been found that reaction force fluctuation and robustness are greatly improved.

This invention was made | formed based on the said knowledge, and the summary is as follows.
(1) In a cylindrical structure including a plurality of cylindrical partial structures arranged continuously, each partial structure has a polygonal first end and substantially the same shape as the first end. Having a second end located on a plane substantially parallel to the plane on which the first end is located, and a side extending between the first end and the second end. The polygonal first end is twisted at a predetermined angle with respect to the polygonal second end, and corresponds to each side of the polygonal first end and the side of the first end. Partial side portions that are a part of the side portions are provided between the sides of the second end portion of the polygonal shape, and valley fold lines are formed diagonally on the side portions of the respective side portions. Mountain fold lines connecting the corners of the first end of the polygon and the corners of the second end of the polygon corresponding to the corner are formed on both sides of the side, and each side part The angle between the mountain fold line and the plane on which the first end is located and the plane on which the second end is located are substantially the same at θ, and a plurality of partial structures constituting the cylindrical structure The angle θ in the partial structure located at one end of the cylindrical structure is smaller than the angle θ in the other partial structure, and for all the partial structures constituting the cylindrical structure A cylindrical structure for an automobile frame structure having an angle θ of 20 ° to 60 °.

(2) Of the plurality of partial structures constituting the cylindrical structure, all the angles θ in the partial structures other than the partial structure located at one end of the cylindrical structure are substantially the same, A cylindrical structure for the automobile frame structure according to (1).

(3) Of the plurality of partial structures constituting the tubular structure, the partial structure is moved from the partial structure located at one end of the tubular structure toward the partial structure located at the other end. The cylindrical structure for an automobile frame structure according to (1), wherein the angle θ in the body increases.

(4) The tubular structure for an automobile frame structure according to any one of the above (1) to (3), wherein an opening is provided in a planar portion of each side portion.

(5) A vehicle frame using the passenger-side main frame and the tubular structure for the vehicle frame structure according to any one of (1) to (4) coupled to the main frame. in structure, the tubular structure, the main frame at the opposite end of the room side of the end portion of the other substructures angle θ than a small portion structure provided tubular structure An automobile frame structure coupled to the vehicle .

(6) A vehicle frame using the cabin-side main frame and the tubular structure for the vehicle frame structure according to any one of (1) to (4) coupled to the main frame. In the structure, the tubular structure has an end opposite to the end of the tubular structure provided with the partial structure having an angle θ smaller than that of the other partial structure. A frame structure for an automobile that is used as a side member or a crash box.

  ADVANTAGE OF THE INVENTION According to this invention, a cylindrical structure with high robustness can be provided, suppressing the reaction force fluctuation | variation at the time of crushing.

FIG. 1 is a diagram illustrating a state when a collision load is input when a cylindrical structure is used as a crash box. FIG. 2 is a schematic perspective view of the cylindrical structure according to the first embodiment of the present invention. FIG. 3 is a schematic side view of the cylindrical structure according to the first embodiment. FIG. 4 is a view showing only a partial structure extracted from the cylindrical structure. FIG. 5 is a diagram illustrating the relationship between the displacement in the length between the end portions of the cylindrical structure and the reaction force per unit mass from the cylindrical structure. FIG. 6 is a diagram illustrating a state in which the cylindrical structure is deformed. FIG. 7 is a diagram illustrating a state in which the cylindrical structure is deformed. FIG. 8 is a diagram illustrating the relationship between the displacement in the length between the end portions of the cylindrical structure and the reaction force per unit mass from the cylindrical structure. FIG. 9 is a schematic perspective view of the cylindrical structure according to the first embodiment of the present invention. FIG. 10 is a diagram schematically showing an automobile frame structure using a cylindrical structure. FIG. 11 is a diagram schematically showing an automobile frame structure using a tubular structure.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are assigned to similar components.

  FIG. 2 is a schematic perspective view of the cylindrical structure of the first embodiment of the present invention, and FIG. 3 is a schematic side view of the cylindrical structure of the present invention. As shown in FIGS. 2 and 3, the cylindrical structure 10 of the present invention has an origami structure including a plurality of cylindrical partial structures 11 to 14 that are continuously arranged. In the illustrated example, the cylindrical structure 10 has four partial structures 11 to 14, but any number of partial structures may be provided as long as it has a plurality of partial structures.

  Of the plurality of partial structures 11 to 14, the uppermost partial structure 11 in FIGS. 2 and 3 will be described as an example. Each of the partial structures 11 includes an upper end portion 11a positioned on the upper side in FIGS. 2 and 3 and a lower end portion 11b positioned on the lower side in FIGS. The lower end portion 11b is located on a plane substantially parallel to the plane on which the upper end portion 11a is located. As can be seen from FIG. 2, in this embodiment, the upper end portion 11a and the lower end portion 11b are both hexagonal, but these ends may have any shape as long as they are substantially the same polygonal shape. .

  Similarly to the partial structure 11, the partial structures 12 to 14 also include upper end portions 12 a to 14 a and lower end portions 12 b to 14 b. In addition, the lower end portion 11b of the upper partial structure (for example, 11) and the upper end portion 12a of the lower partial structure (for example, 12) of the adjacent partial structures have the same shape. These end portions 11b and 12a are coupled to each other.

  The partial structure 11 includes a cylindrical side portion 11c extending between the upper end portion 11a and the lower end portion 11b. The side portion 11c includes the same number of partial side portions 21 as the polygonal corners of the upper end portion 11a and the lower end portion 11b. As for each partial side part 21, the upper end part corresponds to one side of the hexagonal upper end part 11a, and the lower end part thereof corresponds to one side of the hexagonal lower end part 11b. . In other words, the partial side portion 21 which is a part of the side portion 11c is provided between each side of the hexagonal upper end portion 11a and each side of the hexagonal lower end portion 11b corresponding to this side. It can be said that it is a thing. Accordingly, each partial side portion 21 includes each side of the hexagonal upper end portion 11a, each side of the hexagonal lower end portion 11b corresponding to this side, and corner portions located on one side of these sides. It can be said that the region is surrounded by the connected mountain fold line 22 and the mountain fold line 22 connecting the corners located on the other side of these sides.

  As can be seen from FIGS. 2 and 3, the partial structure 11 has a structure in which the lower end 11 b is twisted around the axis of the partial structure 11 with respect to the upper end 11 a. Therefore, each partial side portion 21 does not extend vertically in FIGS. 2 and 3 but extends in an inclined manner. On both sides of each partial side part, a mountain fold line 22 is formed connecting the corner of the hexagonal upper end 11a and the corner of the hexagonal lower end 11b corresponding to this corner, As the partial side portion 21 is inclined, these mountain fold lines 22 are also inclined. In addition, a valley fold line 23 is formed on each partial side portion 21 on the longer diagonal line.

  In the present embodiment, in the adjacent partial structures, the twist direction of the lower end with respect to the upper end is reversed. For example, in the partial structure 11 located at the uppermost position in FIGS. 2 and 3, the lower end portion 11b is twisted counterclockwise as viewed from below with respect to the upper end portion 11a. In the partial structure 12 positioned below the body 11, the lower end 12b is twisted clockwise with respect to the upper end 12a when viewed from below.

Here, considering the partial structure 11 again, since the upper end 11a and the lower end 11b of the partial structure 11 are substantially parallel to each other, the upper end 11a constituting one partial side 21 is the angle between the sides and the mountain fold line 22, and the angle between the sides and the mountain fold line 22 of the lower end portion 11b constituting the side, it is substantially the same at an angle theta ₁₁ together. This angle θ ₁₁ changes according to the angle at which the lower end 11b is twisted around the axis of the partial structure 11 with respect to the upper end 11a. When the partial structure 11 so that the twist angle of the lower end portion 11b increases with respect to the upper end 11a is configured, the angle theta ₁₁ becomes smaller, the torsion of the lower end portion 11b against the upper end portion 11a in the opposite When the partial structure 11 is configured so that the angle becomes small, the angle θ ₁₁ becomes large.

The other partial structures 12 to 14 are similarly configured. In particular, in the second partial structure 12 from the top, the angle between the side of the upper end 12a and the side of the lower end 12b constituting the one partial side part 21 and the mountain fold line 22 is θ _12. . Similarly, the angles of the edge sides and the mountain fold line 22 in the third partial structure 13 from the top and the fourth partial structure 14 from the top are θ ₁₃ and θ ₁₄ , respectively.

The angle θ ₁₁ described above will be described again with reference to FIG. FIG. 4 is a view showing only the partial structure 11 extracted from the cylindrical structure 10. 4A shows the partial structural body 11 in the case of a rectangular tube shape in which the lower end 11b is not twisted with respect to the upper end 11a, and FIG. 4B shows FIGS. Partial structures 11 similar to those shown in FIG.

  As shown to Fig.4 (a), when the partial structure 11 is a square cylinder shape where the lower end part 11b is not twisted with respect to the upper end part 11a, each partial side part 21 is a rectangle. In addition, a valley fold line is not formed on the diagonal line (in FIG. 4A, the line 23 is shown for convenience, but this is merely a diagonal line, not a valley fold line). Absent). At this time, the angle between one ridge line (mountain fold line) 22 that defines each partial side portion 21 and the side of the upper end portion 11 a that forms this partial side portion 21, and each partial side portion 21 are defined. An angle between one ridge line (mountain fold line) and the side of the lower end portion 11b forming the partial side portion 21 is defined as θ ′ (= 90 °).

From this state, when the upper end 11a is twisted by an angle α in the direction indicated by the arrow in FIG. 4A around the center O of the upper end 11a, the partial structure 11 is shown in FIG. 4B. Shape. That is, when the upper end portion 11a is twisted by the angle α with respect to the lower end portion 11b, the shape of the side portion 11c changes accordingly, and thus the shape of each partial side portion 21 changes. After such a change, the angle θ ₁₁ corresponds to the angle θ ′ in FIG.

In the present embodiment, the angle θ ₁₁ defined in this way is 20 ° or more and 60 ° or less, preferably 20 ° or more and 55 ° or less, and more preferably 20 ° or more and 50 ° or less. In addition, in the present embodiment, the angle θ ₁₁ is smaller than the angles θ _{12 to} θ ₁₄ .

In addition, in the present embodiment, the angles θ ₁₂ , θ ₁₃ , and θ ₁₄ are set to 20 ° to 60 °, preferably 20 ° to 55 °, for the other partial structures ₁₂ , ₁₃ , and _14. More preferably, the angle is 20 ° or more and 50 ° or less. In the present embodiment, the angles θ ₁₂ , θ ₁₃ , and θ ₁₄ are the same angle.

Below, the effect of setting the angles θ _{11 to} θ ₁₄ to 20 ° or more and 60 ° or less will be described first. By the way, when a load is applied to the tubular structure 10 from the longitudinal direction of the tubular structure 10, that is, when a load is applied in the direction of arrow A in FIG. 2, the length between the end portions of the tubular structure 10. The relationship between the displacement (more specifically, the displacement of the impactor that applies a load to the tubular structure) and the reaction force per unit mass from the tubular structure 10 is as shown by the solid line in FIG. As can be seen from the solid line in FIG. 5, the relationship between the displacement and the reaction force is not constant, and the reaction force repeatedly increases and decreases as the displacement increases. Among these, within a certain displacement, the maximum value of the reaction force per unit mass is Fmax, and the minimum value per unit mass is Fmin.

  When a load is applied to the cylindrical structure 10 from an angle of 10 ° with respect to the longitudinal direction of the cylindrical structure 10, that is, when a load is applied in the direction of arrow B in FIG. The relationship between the displacement in the length between the end portions of the tube and the reaction force per unit mass from the cylindrical structure 10 is as shown by the broken line in FIG. As can be seen from the broken line in FIG. 5, even when a load is applied at an angle with respect to the longitudinal direction, the reaction force repeatedly increases and decreases as the displacement increases, similarly to the solid line in FIG. 5. Also in this case, the maximum value of the reaction force per unit mass is Fmax and the minimum value per unit mass is Fmin within a certain displacement.

  Here, when the cylindrical structure 10 is used as a front side member or a crash box of an automobile, an allowable value of Fmax is determined. For example, when the cylindrical structure 10 is used as a crash box, when a collision load is applied to the cylindrical structure 10, the maximum value of the load transmitted to the front side member disposed behind the crash box is Fmax. Become. For this reason, if Fmax when a collision load is applied to the cylindrical structure 10 increases beyond the allowable value, a large load is applied to the front side member, which causes unexpected deformation of the front side member. . For this reason, it is necessary to design the cylindrical structure 10 so that the maximum value Fmax of the reaction force becomes a certain allowable value or less when a collision load is applied.

  On the other hand, the energy absorbed by the cylindrical structure 10 when a collision load is applied to the cylindrical structure 10 is proportional to the value obtained by integrating the reaction force per unit mass by displacement. For this reason, in order to increase the energy absorbed by the cylindrical structure 10, it is necessary to keep the reaction force per unit mass constantly high even if the cylindrical structure 10 is displaced.

  Here, Fmin / Fmax may be mentioned as an index indicating the reaction force fluctuation when the tubular structure 10 is displaced. When this Fmin / Fmax is small, the reaction force per unit mass fluctuates greatly, and as a result, the value obtained by integrating the reaction force per unit mass by displacement becomes small. On the contrary, when Fmin / Fmax is large, the fluctuation of the reaction force per unit mass is small, and as a result, the value obtained by integrating the reaction force per unit mass by displacement becomes large. Therefore, it can be said that the energy absorbed by the cylindrical structure 10 increases as Fmin / Fmax increases.

Table 1 shows the angles θ _{11 to} θ ₁₄ between the sides of the upper end portions 11 a to 14 a and the lower end portions ₁₁ b to ₁₄ b and the mountain fold line 22 in each of the partial structures 11 to 14 of the cylindrical structure 10 (hereinafter, these Are collectively referred to as “angle θ”) and Fmax, Fmin, and Fmin / Fmax. Table 1 shows a case where the material of the cylindrical structure 10 is a JSC440W equivalent material, the plate thickness is 1.0 mm, the diameter is about 48.6 mm, and the axial length is 210 mm.

As can be seen from Table 1, when the angle θ is larger than 60 °, Fmin / Fmax is 0.46. On the other hand, when the angle θ is 46.5 ° and 27 °, Fmin / Fmax is 0.5 or more. Here, when a hexagonal column is created from the same material having the same thickness as the cylindrical structure 10 (that is, when it is not an origami structure as in the present invention), as a method for increasing Fmin / Fmax, For example, beads may be provided on the side surface at regular intervals. In a structure provided with such a bead, Fmin / Fmax can generally be increased only to about 0.5. On the other hand, in the cylindrical structure 10 of the present invention, Fmin / Fmax can be set to 0.5 or more by setting the angle θ to 60 ° or less . Therefore, in the tubular structure 10 of the present invention, the energy absorbed by the tubular structure 10 is maintained while keeping the maximum value of the reaction force per unit mass low when the tubular structure 10 is displaced. Can be big.

In the tubular structure 10 of the present invention, the angles θ _{11 to} θ ₁₄ are set to 20 ° or more. This is because if the angles θ _{11 to} θ ₁₄ are further reduced, the angle between the surfaces located on both sides of the mountain fold line 22 and the angle between the surfaces located on both sides of the valley fold line 23 are reduced, and the fracture occurs during crushing. This is because it may occur. Thus, the tubular structure 10 of the present invention, the angle theta ₁₁ through? ₁₄ With 20 ° or more, so as to suppress the breakage.

Next, the effect of setting the angle θ ₁₁ in the partial structure ₁₁ to be smaller than the angles θ _{12 to} θ 14 in the partial structures 12 to ₁₄ will be described. As described above, for example, when a cylindrical structure is used as a crash box, the collision load is always input from the front, that is, in the axial direction of the cylindrical structure (direction of arrow A in FIG. 2) when the automobile collides. However, it may be input from the inclined direction, that is, in the direction inclined with respect to the axial direction of the cylindrical structure (for example, the direction of the arrow B in FIG. 2).

When the angles θ _{11 to} θ ₁₄ are the same for all the partial structures 11 to ₁₄ of the cylindrical structure 10, when a load is input to the cylindrical structure 10 from the inclined direction, the cylindrical structure 10 Stress concentrates at the root of 10. As a result, the cylindrical structure 10 is bent at the root, and as a result, the collision energy cannot be sufficiently absorbed.

This is shown in FIG. FIG. 6 shows a direction in which the cylindrical structures 10 having the same angles θ _{11 to} θ ₁₄ are inclined with respect to the axial direction of all the partial structures 11 to 14 as shown in FIG. The result of analyzing how the cylindrical structure 10 is deformed when a load is input in the direction indicated by arrow B in the drawing is shown. The leftmost side of the figure shows the state of the tubular structure 10 when the displacement of the entire length of the tubular structure 10 due to load is 30 mm, and the displacement is 60 mm toward the right from there. , 90 mm, 120 mm, and 150 mm are shown in the cylindrical structure.

  As can be seen from FIG. 6, when a load is input in the direction indicated by the arrow B, the partial structures 11 and 14 located at both ends of the cylindrical structure 10 are bent and crushed. The partial structural bodies 12 and 13 located between the two are left without being crushed so much. For this reason, depending on the partial structures 12 to 14, it is understood that sufficient energy is not absorbed, and as a result, the collision energy cannot be sufficiently absorbed.

On the other hand, FIG. 7 shows the cylindrical structure 10 in which the angle θ ₁₁ in the partial structure ₁₁ is smaller than the angles θ _{12 to} θ 14 in the partial structures 12 to ₁₄ with respect to the axial direction. The result of analyzing how the cylindrical structure 10 is deformed when a load is input in an inclined direction (direction indicated by an arrow B in the figure) is shown. Similar to FIG. 6, the leftmost side of the drawing shows the state of the cylindrical structure 10 when the displacement of the entire length of the cylindrical structure 10 due to load is 30 mm, and goes to the right from there. The state of the cylindrical structure when the displacement is 60 mm, 90 mm, 120 mm, and 150 mm is shown.

As can be seen from FIG. 7, when a load is input in the direction indicated by the arrow B, the partial structure ₁₁ having an angle θ ₁₁ smaller than the angles θ _{12 to} θ 14 of the other partial structures 12 to ₁₄ is crushed. (Refer to the figures when the displacement is 30 mm and 60 mm). At this time, the other partial structures 12 to 14 are hardly crushed. When the partial structure 11 arranged at one end is crushed, next, the partial structure 12 and the partial structure 13 adjacent to the crushed partial structure 11 start to be crushed (the displacement is 90 mm in the figure). Finally, the partial structure 14 will begin to collapse.

That is, according to the present invention, the partial structure 11 is first crushed because the angle θ ₁₁ in the partial structure ₁₁ is smaller than the angles θ _{12 to} θ 14 of the other partial structures 12 to ₁₄ . In addition, when a part of the cylindrical structure 10 is crushed, the crushing of the cylindrical structure 10 spreads from there, so that the partial structures 12, 13, and 14 are gradually crushed in this order. become. Thereby, according to the present invention, the cylindrical structure 10 is crushed without being broken in the middle, and thus, sufficient energy is absorbed by each of the partial structures 11 to 14. The collision energy can be absorbed.

FIG. 8 shows the relationship between the displacement of the cylindrical structure shown in FIG. 6 during crushing and the reaction force per unit mass (broken line in the figure) and the displacement of the cylindrical structure shown in FIG. It is a figure which shows the relationship (solid line in a figure) with the reaction force per unit mass. As it can be seen from FIG. 8, the broken line (tubular structure shown in FIG. 6) at Fmax is very large in the figure, as a result, with respect to Fmin / Fmax is small Ino, solid line in FIG. (FIG. 7 tubular structure) the Fmax is not so large as shown in, the result, Fmin / Fmax relatively large Kunar. Therefore, according to the cylindrical structure of the present invention shown in FIG. 7, the reaction force per unit mass when the cylindrical structure 10 is displaced relative to the cylindrical structure shown in FIG. It can be said that the energy absorbed by the cylindrical structure 10 can be increased while maintaining the maximum value low.

In the above embodiment, only the partial structure ₁₁ has an angle θ ₁₁ smaller than the other partial structures 12 to 14, and the angles θ _{12 to} θ 14 of the other partial structures 12 to ₁₄ are The angles are the same. However, the angles θ _{11 to} θ 14 of the other partial structures 11 to ₁₄ may be gradually increased from the angle θ ₁₁ toward the angle θ14. In other words, the angle θ in the partial structure may be increased from the partial structure 11 positioned at one end toward the partial structure 14 positioned at the other end.

  Next, a second embodiment of the present invention will be described with reference to FIG. The basic configuration of the cylindrical structure 30 in the second embodiment is the same as the configuration of the cylindrical structure in the first embodiment. However, in the cylindrical structure 30 of the present embodiment, an opening is provided in the planar portion of each partial side portion 21.

  As can be seen from FIG. 9, the cylindrical structure 30 of the second embodiment also has an origami structure including a plurality of cylindrical partial structures 11 to 14, and each of the partial structures 11 to 14 has a hexagonal shape. Upper end portions 11a to 14a, hexagonal lower end portions 11b to 14b, and side portions 11c to 14c. The side portions 11 c to 14 c have a plurality of partial side portions 21, mountain fold lines 22 are formed on both sides of each partial side portion 21, and valley fold lines 23 extending diagonally in the partial side portions 21. Is formed.

  In addition, in the present embodiment, the opening 31 is provided in a planar portion of each partial side portion 21, that is, a portion surrounded by the mountain fold line 22 and the valley fold line 23 of each partial side portion 21. In the present embodiment, the openings 31 are provided in all parts surrounded by the mountain fold line 22 and the valley fold line 23 of the partial side part 21, but the openings 31 are not necessarily formed in all parts. There is no need to be. For example, one opening 31 may be formed in one partial side portion 21.

  Here, in the cylindrical structure 30 having the origami structure as shown in FIG. 9, energy absorption when a collision load is applied or the like is mainly absorbed in the vicinity of the mountain fold line 22 and the valley fold line 23 of the partial side portion 21. Done by the region. In other words, much energy is not absorbed by the planar portion surrounded by the mountain fold line 22 and the valley fold line 23 of the partial side portion 21. For this reason, even if an opening is provided in the planar portion of the partial side portion 21, there is no significant change in absorbed energy. Therefore, according to this embodiment, the cylindrical structure 30 can be reduced in weight while maintaining the amount of energy absorbed when a collision load is applied.

  Next, the usage example of the cylindrical structures 10 and 30 comprised in this way is demonstrated. FIG. 10 is a view schematically showing an automobile frame structure using the tubular structure 10. In the example shown in FIG. 10, the automobile frame structure 40 includes a front side member 41 and a main frame that is located on the vehicle rear side of the front side member 41 and that defines a cabin of the vehicle. 43. In the example shown in FIG. 10, the cylindrical structures 10 and 30 are coupled to the vehicle front side of the front side member 41 and used as a crash box. In particular, the cylindrical structure 10 has a main frame 43 at the end opposite to the end of the cylindrical structure in which the partial structure 11 having a smaller angle θ than the other partial structures 12 to 14 is provided. In front of the front side member 41.

  FIG. 11 is a diagram schematically showing another example of an automobile frame structure using the tubular structure 10. In the example shown in FIG. 11, the automobile frame structure 40 is located on the rear side of the tubular structures 10, 30 used as the front side member, the tubular structures 10, 30 and the passenger compartment of the vehicle. And a cabin frame 42 that defines the room. In the example shown in FIG. 11, the cylindrical structures 10 and 30 are formed by the cylindrical structures 10 provided with the partial structures 11 having an angle θ smaller than those of the other partial structures 12 to 14. Is arranged so that its end faces the outside of the vehicle, that is, toward the front side of the vehicle.

  In this specification, a plurality of terms “almost” are used. The term “substantially” means that the value includes a variation due to a manufacturing error or the like. For example, the upper end portion 11a and the lower end portion 11b are substantially parallel to each other and have substantially the same polygonal shape. However, the upper end portion 11a and the lower end portion 11b are parallel to each other. In addition, when manufactured so as to have substantially the same polygonal shape, it includes cases where both are slightly deviated from parallel due to manufacturing errors or cases where both shapes are slightly different. is there.

10 Tubular structure 11, 12, 13, 14 Partial structure 11a, 12a, 13a, 14a Upper end part 11b, 12b, 13b, 14b Lower end part 11c, 12c, 13c, 14c Side part 21 Partial side part 22 Mountain Fold line (ridge line)
23 Valley fold line (diagonal line)

Claims (6)

In the cylindrical structure comprising a plurality of cylindrical partial structures arranged in succession,
Each partial structure has a polygonal first end and a second polygonal shape that is substantially the same shape as the first end and is positioned on a plane substantially parallel to the plane on which the first end is located. An end and a side extending between the first end and the second end,
The polygonal first end is twisted at a predetermined angle with respect to the polygonal second end, and each side of the polygonal first end and the polygon corresponding to the side of the first end. Partial side portions that are part of the side portions are provided between each side of the second end portion of the shape, and a valley fold line is formed diagonally on each partial side portion and the partial side portions On both sides, a fold line is formed connecting the corner of the first end of the polygon and the corner of the second end of the polygon corresponding to the corner,
The angle between the mountain fold line of each partial side and the plane on which the first end is located and the plane on which the second end is located are substantially the same at θ, and constitute the cylindrical structure. Of the plurality of partial structures, the angle θ in the partial structure located at one end of the cylindrical structure is smaller than the angle θ in the other partial structures and all the components constituting the cylindrical structure are included. A tubular structure for a frame structure for an automobile, wherein the angle θ is 20 ° or more and 60 ° or less for the partial structure.   The angles θ in the partial structures other than the partial structure located at one end of the cylindrical structure among the plurality of partial structures constituting the cylindrical structure are substantially the same. A tubular structure for the automobile frame structure as described.   The angle in the partial structure as it goes from the partial structure located at one end of the tubular structure to the partial structure located at the other end of the plurality of partial structures constituting the tubular structure The cylindrical structure for an automobile frame structure according to claim 1, wherein θ increases.   The cylindrical structure for a frame structure for an automobile according to any one of claims 1 to 3, wherein an opening is provided in a planar portion of each of the partial side portions. In the vehicle frame structure using the main frame on the cabin side and the tubular structure for the vehicle frame structure according to any one of claims 1 to 4 coupled to the main frame,
The end of the tubular structure opposite to the end of the tubular structure provided with the partial structure having an angle θ smaller than that of the other partial structure is coupled to the main frame on the passenger cabin side. , Automotive frame structure. In the vehicle frame structure using the main frame on the cabin side and the tubular structure for the vehicle frame structure according to any one of claims 1 to 4 coupled to the main frame ,
The tubular structure has an end opposite to the end of the tubular structure provided with a partial structure having a smaller angle θ than the other partial structures, coupled to the passenger-side main frame, Frame structure used as a side member or crash box.

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